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  • 1. Amundsen, Brage Høyem
    et al.
    Ericsson, Madelene
    Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway.
    Seland, John Georg
    Pavlin, Tina
    Ellingsen, Øyvind
    Brekken, Christian
    A comparison of retrospectively self-gated magnetic resonance imaging and high-frequency echocardiography for characterization of left ventricular function in mice.2011In: Laboratory animals, ISSN 1758-1117, Vol. 45, no 1, p. 31-37Article in journal (Refereed)
    Abstract [en]

    Non-invasive imaging methods like echocardiography and magnetic resonance imaging (MRI) are very valuable in longitudinal follow-up studies of cardiac function in small animals. To be able to compare results from studies using different methods, and explain possible differences, it is important to know the agreement between these methods. As both self-gated high-field MRI and high-frequency echocardiography (hf-echo) M-mode are potential methods for evaluation of left ventricular (LV) function in healthy mice, our aim was to assess the agreement between these two methods. Fifteen healthy female C57BL/6J mice underwent both self-gated MRI and hf-echo during the same session of light isoflurane anaesthesia. LV dimensions were estimated offline, and agreement between the methods and reproducibility for the two methods assessed using Bland-Altman methods. In summary, hf-echo M-mode had better inter-observer repeatability than self-gated MRI for all measured parameters. Compared with hf-echo, systolic posterior wall thicknesses were significantly higher when measured by MRI, while diastolic anterior wall thicknesses were found to be significantly smaller. MRI measurements of diastolic LV diameter were also higher using MRI, resulting in larger fractional shortening values compared with the values obtained by hf-echo. In conclusion, hf-echo M-mode is easy to apply, has high temporal and spatial resolution, and good reproducibility. Self-gated MRI might be advantageous in cases of abnormal LV geometry and heterogeneous regional myocardial function, especially with improvements in spatial resolution. The moderate agreement between the methods must be taken into account when comparing studies using the two modalities.

  • 2. Andersen, Sonja
    et al.
    Ericsson, Madelene
    Department of Cancer Research and Molecular Medicine, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim.
    Dai, Hong Yan
    Peña-Diaz, Javier
    Slupphaug, Geir
    Nilsen, Hilde
    Aarset, Harald
    Krokan, Hans E
    Monoclonal B-cell hyperplasia and leukocyte imbalance precede development of B-cell malignancies in uracil-DNA glycosylase deficient mice2005In: DNA Repair, ISSN 1568-7864, E-ISSN 1568-7856, Vol. 4, no 12, p. 1432-1441Article in journal (Refereed)
    Abstract [en]

    Ung-deficient mice have reduced class switch recombination, skewed somatic hypermutation, lymphatic hyperplasia and a 22-fold increased risk of developing B-cell lymphomas. We find that lymphomas are of follicular (FL) and diffuse large B-cell type (DLBCL). All FLs and 75% of the DLBCLs were monoclonal while 25% were biclonal. Monoclonality was also observed in hyperplasia, and could represent an early stage of lymphoma development. Lymphoid hyperplasia occurs very early in otherwise healthy Ung-deficient mice, observed as a significant increase of splenic B-cells. Furthermore, loss of Ung also causes a significant reduction of T-helper cells, and 50% of the young Ung(-/-) mice investigated have no detectable NK/NKT-cell population in their spleen. The immunological imbalance is confirmed in experiments with spleen cells where the production of the cytokines interferon gamma, interleukin 6 and interleukin 2 is clearly different in wild type and in Ung-deficient mice. This suggests that Ung-proteins, directly or indirectly, have important functions in the immune system, not only in the process of antibody maturation, but also for production and functions of immunologically important cell types. The immunological imbalances shown here in the Ung-deficient mice may be central in the development of lymphomas in a background of generalised lymphoid hyperplasia.

  • 3. Arend, A
    et al.
    Aunapuu, M
    Masso, R
    Selstam, Gunnar
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Prostaglandins of the E-series inhibit connective tissue proliferation in the liver wound of the rat2005In: Annals of Anatomy, ISSN 0940-9602, E-ISSN 1618-0402, Vol. 187, no 1, p. 57-62Article in journal (Refereed)
    Abstract [en]

    The present study was undertaken to relate wound heating of an internal organ to prostaglandins of the E and F series. A small liver wound was induced by a galvanic cauter via the abdominal route under general anesthesia and prostaglandin E-1, E-2 and F-2 alpha were injected twice daily at a dose of 250 mu g/kg. Proliferation of the connective tissue in the liver wound was estimated morphometrically 6 days after liver wound infliction. Levels of prostaglandins E-2 and F-2 alpha were measured in the liver wound as well as in normal liver tissue from adjacent lobes using radioimmunoassay. The results show that exogenous prostaglandins of the E-series suppress connective tissue proliferation. Three minutes after the last prostaglandin E-2 injection, high prostaglandin concentrations were measured both in the tiver wound and in the liver tissue of the adjacent lobe. Prostaglandin F-2 alpha injections had no effect on wound heating. We believe that the rat thermic liver wound model can be used for different studies on wound heating mechanisms and that prostaglandins of the E-series are involved in wound heating in the specific time period studied.

  • 4.
    Bengtsson, Åsa
    Umeå University, Faculty of Science and Technology, Chemistry.
    Solubility and Surface Complexation Studies of Apatites2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Apatites are a diverse class of phosphate minerals that are important in a great variety of natural and industrial processes. They are, for example, used as raw material in fertiliser production and in the remediation of metal-contaminated soils. Hydroxyapatite Ca5(PO4)3OH, (HAP) and fluorapatite Ca5(PO4)3F, (FAP) are similar to the biological apatite that is the main constituent of mammalian bone and teeth, and they are therefore promising materials for artificial bone and tooth implants.

    This thesis is a summary of four papers with focus on dissolution and surface complexation reactions of HAP and FAP in the absence and presence of both organic ligands and the natural and commonly occurring iron oxide goethite (α-FeOOH).

    The dissolution and surface complexation of HAP and FAP was investigated with a combination of different techniques. Potentiometric acid/base titrations and batch experiments were combined with X-ray Photoelectron Spectroscopy (XPS) and Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) Spectroscopy to generate dissolution and surface complexation models for both apatites. The results from these studies showed that both apatites form surface layers that are different from their bulk compositions when equilibrated in aqueous solutions. The modeling efforts predicted speciation of these surfaces as well as the concentration of the dissolution products in the solution.

    The interaction between organic ligands and the apatite surfaces was also investigated and the results from this study show that the organic ligands form outer-sphere complexes on the apatite surfaces over a large pH interval, and that this adsorption enhances the dissolution of apatites.

    The presence of goethite also enhances the dissolution of FAP as it acts as a sink for the phosphate released from FAP. Phase transformation in this system was detected using ATR-FTIR as the phosphate adsorbed to the goethite surface precipitates as FePO4 (s) after approximately 15 days of reaction time. This changes the speciation, and possibly also the bioavailability of phosphate in this two-mineral system.

  • 5.
    Berglund, Anders
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kettaneh, Nouna
    Umetrics Inc., Kinnelon, NJ, USA.
    Uppgård, Lise-Lott
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wold, Svante
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bendwell, Nancy
    Tembec Inc., Temiscaming, Quebec, Canada.
    Cameron, Dave R
    Tembec Inc., Temiscaming, Quebec, Canada.
    The GIFI approach to non-linear PLS modeling2001In: Journal of Chemometrics, ISSN 0886-9383, E-ISSN 1099-128X, Vol. 15, no 4, p. 321-36Article in journal (Refereed)
    Abstract [en]

    The GIFI approach to non-linear modeling involves the transformation of quantitative variables to a set of 1/0 dummies in a similar manner to the way qualitative variables are coded. This is followed by analyzing the sets of 1/0 dummies by principal component analysis, multiple regression or, as discussed here, PLS. The patterns of the resulting coefficients indicate the nature of the non-linearities in the data. Here the potential uses and limitations of PLS regression, in combination with four variants of GIFI coding, are investigated using both simulated and empirical data sets.

  • 6.
    Bixo, Marie
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Ovarian steroids in rat and human brain: effects of different endocrine states1987Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Ovarian steroid hormones are known to produce several different effects in the brain. In addition to their role in gonadotropin release, ovulation and sexual behaviour they also seem to affect mood and emotions, as shown in women with the premenstrual tension syndrome. Some steroids have the ability to affect brain excitability. Estradiol decreases the electroshock threshold while progesterone acts as an anti-convulsant and anaesthetic in both animals and humans. Several earlier studies have shown a specific uptake of several steroids in the animal brain but only a few recent studies have established the presence of steroids in the human brain.

    In the present studies, the dissections of rat and human brains were carried out macroscopically and areas that are considered to be related to steroid effects were chosen. Steroid concentrations were measured by radioimmunoassay after extraction and separation with celite chromatography. The accuracy and specificity of these methods were estimated.

    In the animal studies, immature female rats were treated with Pregnant Mare's Serum Gonadotropin (PMSG) to induce simultaneous ovulations. Concentrations of estradiol and progesterone were measured in seven brain areas pre- and postovulatory. The highest concentration of estradiol, pre- and postovulatory, was found in the hypothalamus and differences between the two cycle phases were detected in most brain areas. The preovulatory concentrations of progesterone were low and the highest postovulatory concentration was found in the cerebral cortex.

    In one study, the rats were injected with pharmacological doses of progesterone to induce "anaesthesia". High uptake of progesterone was found and a regional variation in the formation of 5<*-pregnane-3,20-dione in the brain with the highest ratio in the medulla oblongata.

    Concentrations of progesterone, 5a-pregnane-3*20-dione, estradiol and testosterone were determined in 17 brain areas of fertile compared to postmenopausal women. All steroids displayed regional differences in brain concentrations. Higher concentrations of estradiol and progesterone were found in the fertile compared to the postmenopausal women.

    In summary, these studies show that the concentrations of ovarian steroids in the brain are different at different endocrine states in both rats and humans and that there are regional differences in brain steroid distribution.

  • 7.
    Broman, T
    et al.
    Department of CBRN Defence and Security, Swedish Defence Research Agency, Umeå.
    Thelaus, J
    Andersson, A-C
    Department of CBRN Defence and Security, Swedish Defence Research Agency, Umeå.
    Bäckman, S
    Department of CBRN Defence and Security, Swedish Defence Research Agency, Umeå.
    Wikström, P
    Department of CBRN Defence and Security, Swedish Defence Research Agency, Umeå.
    Larsson, E
    Department of CBRN Defence and Security, Swedish Defence Research Agency, Umeå.
    Granberg, M
    Department of CBRN Defence and Security, Swedish Defence Research Agency, Umeå.
    Karlsson, L
    Department of CBRN Defence and Security, Swedish Defence Research Agency, Umeå.
    Bäck, E
    Department of Infectious Diseases, Örebro University Hospital, Örebro.
    Eliasson, H
    Department of Infectious Diseases, Örebro University Hospital, Örebro.
    Mattsson, R
    National Veterinary Institute, Uppsala.
    Sjöstedt, Anders
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Forsman, M
    Department of CBRN Defence and Security, Swedish Defence Research Agency, Umeå.
    Molecular Detection of Persistent Francisella tularensis Subspecies holarctica in Natural Waters2011In: International Journal of Microbiology, ISSN 1687-918X, E-ISSN 1687-9198, Vol. 2011, p. Article ID 851946-Article in journal (Refereed)
    Abstract [en]

    Tularemia, caused by the bacterium Francisella tularensis, where F. tularensis subspecies holarctica has long been the cause of endemic disease in parts of northern Sweden. Despite this, our understanding of the natural life-cycle of the organism is still limited. During three years, we collected surface water samples (n = 341) and sediment samples (n = 245) in two areas in Sweden with endemic tularemia. Real-time PCR screening demonstrated the presence of F. tularenis lpnA sequences in 108 (32%) and 48 (20%) of the samples, respectively. The 16S rRNA sequences from those samples all grouped to the species F. tularensis. Analysis of the FtM19InDel region of lpnA-positive samples from selected sampling points confirmed the presence of F. tularensis subspecies holarctica-specific sequences. These sequences were detected in water sampled during both outbreak and nonoutbreak years. Our results indicate that diverse F. tularensis-like organisms, including F. tularensis subsp. holarctica, persist in natural waters and sediments in the investigated areas with endemic tularemia.

  • 8.
    Buckland, Robert J
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Watt, Danielle L
    Chittoor, Balasubramanyam
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Nilsson, Anna Karin
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Kunkel, Thomas A
    Chabes, Andrei
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Increased and Imbalanced dNTP Pools Symmetrically Promote Both Leading and Lagging Strand Replication Infidelity2014In: PLOS Genetics, ISSN 1553-7390, E-ISSN 1553-7404, Vol. 10, no 12, article id e1004846Article in journal (Refereed)
    Abstract [en]

    The fidelity of DNA replication requires an appropriate balance of dNTPs, yet the nascent leading and lagging strands of the nuclear genome are primarily synthesized by replicases that differ in subunit composition, protein partnerships and biochemical properties, including fidelity. These facts pose the question of whether imbalanced dNTP pools differentially influence leading and lagging strand replication fidelity. Here we test this possibility by examining strand-specific replication infidelity driven by a mutation in yeast ribonucleotide reductase, rnr1-Y285A, that leads to elevated dTTP and dCTP concentrations. The results for the CAN1 mutational reporter gene present in opposite orientations in the genome reveal that the rates, and surprisingly even the sequence contexts, of replication errors are remarkably similar for leading and lagging strand synthesis. Moreover, while many mismatches driven by the dNTP pool imbalance are efficiently corrected by mismatch repair, others are repaired less efficiently, especially those in sequence contexts suggesting reduced proofreading due to increased mismatch extension driven by the high dTTP and dCTP concentrations. Thus the two DNA strands of the nuclear genome are at similar risk of mutations resulting from this dNTP pool imbalance, and this risk is not completely suppressed even when both major replication error correction mechanisms are genetically intact.

  • 9.
    Carlsson, Lena
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Fischer, Christine
    Karoloinska Institute.
    Sjöberg, Gunnnar
    Karoloinska Institute.
    Robson, Richard M
    Iowa Statte University.
    Sejersen, Thomas
    Karoloinska Institute.
    Thornell, Lars-Eric
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Cytoskeletal derangements in hereditary myopathy with a desmin L345P mutation2002In: Acta Neuropathologica, ISSN 0001-6322, E-ISSN 1432-0533, Vol. 104, no 5, p. 493-504Article in journal (Refereed)
    Abstract [en]

    Patients with abnormal accumulations of desmin have been described in myopathies with or without cardiac involvement. Desmin deposits were sometimes associated with abnormal aggregates of other cytoskeletal proteins. In the present study we present how the cytoskeletal organisation of desmin, nestin, synemin, paranemin, plectin and alphaB-crystallin is altered in skeletal muscles from a patient with a L345P mutation in the desmin gene. In general, accumulations of desmin together with synemin, nestin, plectin and alphaB-crystallin were present between myofibrils and beneath the sarcolemma. However, as the biopsy samples were very myopathic, large variability in fibre size and fibre maturation was seen, thus the myofibrillar content and the cytoskeletal organisation varied considerably. In cultured satellite cells from the patient, desmin aggregates were not observed in initial passages, but occurred over time in culture in the form of perinuclear, peripheral or cytoplasmic deposits. Nestin colocalised to the abnormal desmin deposits to a larger extent than did vimentin. alphaB-Crystallin was only present in cells with a disrupted desmin network. Plectin was altered in a subset of cells with a disrupted desmin network, whereas synemin and paranemin were not detected. We conclude that the L345P desmin mutation has a profound influence on the cytoskeletal organisation both in vivo and in vitro, which reflects the pathogenesis of the desmin myopathy.

  • 10.
    Carlsson, Lena
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Li, Z L
    Université Paris.
    Paulin, D
    Université Paris.
    Price, M G
    Baylor College of Medicine.
    Breckler, J
    San Fransisco State University.
    Robson, R M
    Iowa State University.
    Wiche, G
    University of Vienna.
    Thornell, Lars-Eric
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Differences in the distribution of synemin, paranemin, and plectin in skeletal muscles of wild-type and desmin knock-out mice2000In: Histochemistry and Cell Biology, ISSN 0948-6143, E-ISSN 1432-119X, Vol. 114, no 1, p. 39-47Article in journal (Refereed)
    Abstract [en]

    Mice lacking the gene encoding for the intermediate filament protein desmin have a surprisingly normal myofibrillar organization in skeletal muscle fibers, although myopathy develops in highly used muscles. In the present study we examined how synemin, paranemin, and plectin, three key cytoskeletal proteins related to desmin, are organized in normal and desmin knock-out (K/O) mice. We show that in wild-type mice, synemin, paranemin, and plectin were colocalized with desmin in Z-disc-associated striations and at the sarcolemma. All three proteins were also present at the myotendinous junctions and in the postsynaptic area of motor endplates. In the desmin K/O mice the distribution of plectin was unaffected, whereas synemin and paranemin were partly affected. The Z-disc-associated striations were in general no longer present in between the myofibrils. In contrast, at the myotendinous and neuromuscular junctions synemin and paranemin were still present. Our study shows that plectin differs from synemin and paranemin in its binding properties to the myofibrillar Z-discs and that the cytoskeleton in junctional areas is particularly complex in its organization.

  • 11.
    Carlsson, Lena
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Thornell, Lars-Eric
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Desmin-related myopathies in mice and man2001In: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 171, no 3, p. 341-8Article in journal (Refereed)
    Abstract [en]

    Desmin, the main intermediate filament (IF) protein in skeletal and heart muscle cells, is of great importance as a part of the cytoskeleton. The IFs surround and interlink myofibrils, and connect the peripheral myofibrils with the sarcolemma. In myotendinous junctions and neuromuscular junctions of skeletal muscle fibres, desmin is enriched. In the heart, desmin is increased at intercalated discs, the attachment between cardiomyocytes, and it is the main component in Purkinje fibres of the conduction system. Desmin is the first muscle-specific protein to appear during myogenesis. Nevertheless, lack of desmin, as shown from experiments with desmin knockout (K/O) mice, does not influence myogenesis or myofibrillogenesis. However, the desmin knock-out mice postnatally develop a cardiomyopathy and a muscle dystrophy in highly used skeletal muscles. In other skeletal muscles the organization of myofibrils is remarkably unaffected. Thus, the main consequence of the lack of desmin is that the muscle fibres become more susceptible to damage. The loss of membrane integrity leads to a dystrophic process, with degeneration and fibrosis. In the heart cardiac failure develops, whereas in affected skeletal muscles regenerative attempts are seen. In humans, accumulations of desmin have been a hallmark for presumptive desmin myopathies. Recent investigations have shown that some families with such a myopathy have a defect in the gene coding for alphaB-crystallin, whereas others have mutations in the desmin gene. Typical features of these patients are cardiac affections and muscle weakness. Thus, mutations in the desmin gene is pathogenic for a distinct type of muscle disorder.

  • 12.
    Chorell, Elin
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Mapping the consequenses of physical exercise and nutrition on human health: A predictive metabolomics approach2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Human health is a complex and wide-ranging subject far beyond nutrition and physical exercise. Still, these factors have a huge impact on global health by their ability to prevent diseases and thus promote health. Thus, to identify health risks and benefits, it is necessary to reveal the underlying mechanisms of nutrition and exercise, which in many cases follows a complex chain of events. As a consequence, current health research is generating massive amounts of data from anthropometric parameters, genes, proteins, small molecules (metabolites) et cetera, with the intent to understand these mechanisms. For the study of health responses, especially related to physical exercise and nutrition, alterations in small molecules (metabolites) are in most cases immediate and located close to the phenotypic level and could therefore provide early signs of metabolic imbalances. Since there are roughly as many different responses to exercise and nutrients as there are humans, this quest is highly multifaceted and will benefit from an interpretation of treatment effects on a general as well as on an individual level. This thesis involves the application of chemometric methods to the study of global metabolic reactions, i.e. metabolomics, in a strategy coined predictive metabolomics. Via the application of predictive metabolomics an extensive hypothesis-free biological interpretation has been carried out of metabolite patterns in blood, acquired using gas chromatography-mass spectrometry (GC-MS), related to physical exercise, nutrition and diet, all in the context of human health. In addition, the chemometrics methodology have computational benefits concerning the extraction of relevant information from information-rich data as well as for interpreting general treatment effects and individual responses, as exemplified throughout this work. Health concerns all lifestages, thus this thesis presents a strategic framework in combination with comprehensive interpretations of metabolite patterns throughout life. This includes a broad range of human studies revealing metabolic patterns related to the impact of physical exercise, macronutrient modulation and different fitness status in young healthy males, short and long term dietary treatments in overweight post menopausal women as well as metabolic responses related to probiotics treatment and early development in infants. As a result, the studies included in the thesis have revealed metabolic patterns potentially indicative of an anti-catabolic response to macronutrients in the early recovery phase following exercise. Moreover, moderate differences in the metabolome associated with cardiorespiratory fitness level were detected, which could be linked to variation in the inflammatory and antioxidaive defense system. This work also highlighted mechanistic information that could be connected to dietary related weight loss in overweight and obese postmenopausal women in relation to short as well as long term dietary effects based on different macronutrient compositions. Finally, alterations were observed in metabolic profiles in relation to probiotics treatment in the second half of infancy, suggesting possible health benefits of probiotics supplementation at an early age.

     

  • 13. Crona, Mikael
    et al.
    Hofer, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Astorga-Wells, Juan
    Sjöberg, Britt-Marie
    Tholander, Fredrik
    Biochemical Characterization of the Split Class II Ribonucleotide Reductase from Pseudomonas aeruginosa2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 7, article id e0134293Article in journal (Refereed)
    Abstract [en]

    The opportunistic pathogen Pseudomonas aeruginosa can grow under both aerobic and anaerobic conditions. Its flexibility with respect to oxygen load is reflected by the fact that its genome encodes all three existing classes of ribonucleotides reductase (RNR): the oxygen-dependent class I RNR, the oxygen-indifferent class II RNR, and the oxygen-sensitive class III RNR. The P. aeruginosa class II RNR is expressed as two separate polypeptides (NrdJa and NrdJb), a unique example of a split RNR enzyme in a free-living organism. A split class II RNR is also found in a few closely related gamma-Proteobacteria. We have characterized the P. aeruginosa class II RNR and show that both subunits are required for formation of a biologically functional enzyme that can sustain vitamin B12-dependent growth. Binding of the B12 coenzyme as well as substrate and allosteric effectors resides in the NrdJa subunit, whereas the NrdJb subunit mediates efficient reductive dithiol exchange during catalysis. A combination of activity assays and activity-independent methods like surface plasmon resonance and gas phase electrophoretic macromolecule analysis suggests that the enzymatically active form of the enzyme is a (NrdJa-NrdJb) 2 homodimer of heterodimers, and a combination of hydrogen-deuterium exchange experiments and molecular modeling suggests a plausible region in NrdJa that interacts with NrdJb. Our detailed characterization of the split NrdJ from P. aeruginosa provides insight into the biochemical function of a unique enzyme known to have central roles in biofilm formation and anaerobic growth.

  • 14.
    Dahlgren, Markus K
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Zetterström, Caroline E
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gylfe, Åsa
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Linusson, Anna
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Elofsson, Mikael
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Statistical molecular design of a focused salicylidene acylhydrazide library and multivariate QSAR of inhibition of type III secretion in the Gram-negative bacterium Yersinia2010In: Bioorganic & Medicinal Chemistry, ISSN 0968-0896, E-ISSN 1464-3391, Vol. 18, no 7, p. 2686-2703Article in journal (Refereed)
    Abstract [en]

    A combined application of statistical molecular design (SMD), quantitative structure-activity relationship (QSAR) modeling and prediction of new active compounds was effectively used to develop salicylidene acylhydrazides as inhibitors of type III secretion (T3S) in the Gram-negative pathogen Yersinia pseudotuberculosis. SMD and subsequent synthesis furnished 50 salicylidene acylhydrazides in high purity. Based on data from biological evaluation in T3S linked assays 18 compounds were classified as active and 25 compounds showed a dose-dependent inhibition. The 25 compounds were used to compute two multivariate QSAR models and two multivariate discriminant analysis models were computed from both active and inactive compounds. Three of the models were used to predict 4416 virtual compounds in consensus and eight new compounds were selected as an external test set. Synthesis and biological evaluation of the test set in Y. pseudotuberculosis and the intracellular pathogen Chlamydia trachomatis validated the models. Y. pseudotuberculosis and C. trachomatis cell-based infection models showed that compounds identified in this study are selective and non-toxic inhibitors of T3S dependent virulence.

  • 15.
    Dahlgren, Markus
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Kauppi, Anna
    Umeå University, Faculty of Science and Technology, Chemistry.
    Olsson, Ing-Marie
    Umeå University, Faculty of Science and Technology, Chemistry.
    Linusson Jonsson, Anna
    Umeå University, Faculty of Science and Technology, Chemistry.
    Elofsson, Mikael
    Umeå University, Faculty of Science and Technology, Chemistry.
    Design, Synthesis, and Multivariate Quantitative Structure-Activity Relationship of Salicylanilides-Potent Inhibitors of Type III Secretion in Yersinia2007In: Journal of Medicinal Chemistry, ISSN 0022-2623, E-ISSN 1520-4804, Vol. 50, no 24, p. 6177-6188Article in journal (Refereed)
    Abstract [en]

    Analogues to the salicylanilide N-(4-Chlorophenyl)-2-acetoxy-3,5-diiodobenzamide, 1a, an inhibitor of type III secretion (T3S) in Yersinia, were selected, synthesized, and biologically evaluated in three cycles. First, a set of analogues with variations in the salicylic acid ring moiety was synthesized to probe possible structural variation. A basic structure-activity relationship was established and then used to cherry-pick compounds from a principal component analysis score plot of salicylanilides to generate a second set. A third set with increased likelihood of biological activity was designed using D-optimal onion design. A quantitative structure-activity relationship model using hierarchical partial least-square regression to latent structures (Hi-PLS) was computed using PLS score vectors of building blocks correlated to the % inhibition of T3S as a response. A PLS discriminant analysis (PLS-DA) model was derived using the same descriptor set as that for the Hi-PLS model. Both models were validated with an external test set.

  • 16.
    Dahlin, Anna M
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Henriksson, Maria L
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Van Guelpen, Bethany
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Stenling, Roger
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Öberg, Åke
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Rutegård, Jörgen
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Palmqvist, Richard
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Colorectal cancer prognosis depends on T-cell infiltration and molecular characteristics of the tumor2011In: Modern Pathology, ISSN 0893-3952, E-ISSN 1530-0285, Vol. 24, p. 671-682Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to relate the density of tumor infiltrating T cells to cancer-specific survival in colorectal cancer, taking into consideration the CpG island methylator phenotype (CIMP) and microsatellite instability (MSI) screening status. The T-cell marker CD3 was stained by immunohistochemistry in 484 archival tumor tissue samples. T-cell density was semiquantitatively estimated and scored 1-4 in the tumor front and center (T cells in stroma), and intraepithelially (T cells infiltrating tumor cell nests). Total CD3 score was calculated as the sum of the three CD3 scores (range 3-12). MSI screening status was assessed by immunohistochemistry. CIMP status was determined by quantitative real-time PCR (MethyLight) using an eight-gene panel. We found that patients whose tumors were highly infiltrated by T cells (total CD3 score ≥7) had longer survival compared with patients with poorly infiltrated tumors (total CD3 score ≤4). This finding was statistically significant in multivariate analyses (multivariate hazard ratio, 0.57; 95% confidence interval, 0.31-1.00). Importantly, the finding was consistent in rectal cancer patients treated with preoperative radiotherapy. Although microsatellite unstable tumor patients are generally considered to have better prognosis, we found no difference in survival between microsatellite unstable and microsatellite stable (MSS) colorectal cancer patients with similar total CD3 scores. Patients with MSS tumors highly infiltrated by T cells had better prognosis compared with intermediately or poorly infiltrated microsatellite unstable tumors (log rank P=0.013). Regarding CIMP status, CIMP-low was associated with particularly poor prognosis in patients with poorly infiltrated tumors (multivariate hazard ratio for CIMP-low versus CIMP-negative, 3.07; 95% confidence interval, 1.53-6.15). However, some subset analyses suffered from low power and are in need of confirmation by independent studies. In conclusion, patients whose tumors are highly infiltrated by T cells have a beneficial prognosis, regardless of MSI, whereas the role of CIMP status in this context is less clear.

  • 17.
    Degerman, Sofie
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Josefsson, Maria
    Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR).
    Nordin Adolfsson, Annelie
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Wennstedt, Sigrid
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Landfors, Mattias
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Haider, Zahra
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Pudas, Sara
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Hultdin, Magnus
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Adolfsson, Rolf
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Maintained memory in aging is associated with young epigenetic age2017In: Neurobiology of Aging, ISSN 0197-4580, E-ISSN 1558-1497, Vol. 55, p. 167-171Article in journal (Refereed)
    Abstract [en]

    Epigenetic alterations during aging have been proposed to contribute to decline in physical and cognitive functions, and accelerated epigenetic aging has been associated with disease and all-cause mortality later in life. In this study, we estimated epigenetic age dynamics in groups with different memory trajectories (maintained high performance, average decline, and accelerated decline) over a 15-year period. Epigenetic (DNA-methylation [DNAm]) age was assessed, and delta age (DNAm age - chronological age) was calculated in blood samples at baseline (age: 55-65 years) and 15 years later in 52 age- and gender-matched individuals from the Betula study in Sweden. A lower delta DNAm age was observed for those with maintained memory functions compared with those with average (p = 0.035) or accelerated decline (p = 0.037). Moreover, separate analyses revealed that DNAm age at follow-up, but not chronologic age, was a significant predictor of dementia (p = 0.019). Our findings suggest that young epigenetic age contributes to maintained memory in aging.

  • 18.
    Domkin, Vladimir
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Chabes, Andrei
    Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS). Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Phosphines are ribonucleotide reductase reductants that act via C-terminal cysteines similar to thioredoxins and glutaredoxins2014In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 4, p. 5539-Article in journal (Refereed)
    Abstract [en]

    Ribonucleotide reductases (RNRs) catalyze the formation of 2'-deoxyribonucleotides. Each polypeptide of the large subunit of eukaryotic RNRs contains two redox-active cysteine pairs, one in the active site and the other at the C-terminus. In each catalytic cycle, the active-site disulfide is reduced by the C-terminal cysteine pair, which in turn is reduced by thioredoxins or glutaredoxins. Dithiols such as DTT are used in RNR studies instead of the thioredoxin or glutaredoxin systems. DTT can directly reduce the disulfide in the active site and does not require the C-terminal cysteines for RNR activity. Here we demonstrate that the phosphines tris(2-carboxyethyl)phosphine (TCEP) and tris(3-hydroxypropyl)phosphine (THP) are efficient non-thiol RNR reductants, but in contrast to the dithiols DTT, bis(2-mercaptoethyl)sulfone (BMS), and (S)-(1,4-dithiobutyl)-2-amine (DTBA) they act specifically via the C-terminal disulfide in a manner similar to thioredoxin and glutaredoxin. The simultaneous use of phosphines and dithiols results in ~3-fold higher activity compared to what is achieved when either type of reductant is used alone. This surprising effect can be explained by the concerted action of dithiols on the active-site cysteines and phosphines on the C-terminal cysteines. As non-thiol and non-protein reductants, phosphines can be used to differentiate between the redox-active cysteine pairs in RNRs.

  • 19.
    Eklöf, Vincy
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Van Guelpen, Bethany
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Hultdin, Johan
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Clinical chemistry.
    Johansson, Ingegerd
    Umeå University, Faculty of Medicine, Department of Odontology.
    Hallmans, Göran
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Nutritional Research.
    Palmqvist, Richard
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    The reduced folate carrier (RFC1) 80G>A and folate hydrolase 1 (FOLH1) 1561C>T polymorphisms and the risk of colorectal cancer: a nested case-referent study2008In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 68, no 5, p. 393-401Article in journal (Refereed)
    Abstract [en]

    Objective. Polymorphisms in genes involved in folate uptake and metabolism may affect folate status and, thereby, the risk of cancer. In this nested case‐referent study, we related two such polymorphisms, reduced folate carrier (RFC1) 80G>A and folate hydrolase 1 (FOLH1) 1561C>T, to the risk of colorectal cancer, taking into account pre‐diagnostic plasma folate and total homocysteine concentrations and the MTHFR 677C>T polymorphism, which were analysed in a previous study.

    Material and methods. Subjects were 220 cases and 414 matched referents from the population‐based Northern Sweden Health and Disease Study.

    Results. The RFC1 80A‐allele was associated with reduced plasma folate and elevated plasma total homocysteine concentrations, but the result was statistically significant only for folate. In contrast, the FOLH1 1561T‐allele was associated with higher plasma folate and reduced plasma total homocysteine concentrations, and the result was statistically significant only for homocysteine. Neither polymorphism was related to the risk of colorectal cancer, either in univariate analysis or after adjusting for body mass index, current smoking, recreational and occupational physical activity and alcohol intake. Further adjustment for folate or homocysteine status or the MTHFR 677C>T polymorphism did not affect risk estimates. Subjects with the RFC1 80AA genotype in combination with low plasma folate concentrations or the MTHFR 677TT genotype had a reduced risk of colorectal cancer of borderline statistical significance.

    Conclusions. These findings suggest that although the RFC1 80G>A and FOLH1 1561C>T polymorphisms may influence folate status, they are not likely to have a major independent role in the development of colorectal cancer.

    Read More: http://informahealthcare.com/doi/abs/10.1080/00365510701805431

  • 20.
    Ericsson, Madelene
    et al.
    Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, and Department of Medical Imaging, St. Olavs Hospital, Olav Kyrres gate 9, NO-7489 Trondheim, Norway.
    Andersson, Kristin B
    Amundsen, Brage H
    Torp, Sverre H
    Sjaastad, Ivar
    Christensen, Geir
    Sejersted, Ole M
    Ellingsen, Øyvind
    High-intensity exercise training in mice with cardiomyocyte-specific disruption of Serca22010In: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 108, no 5, p. 1311-1320Article in journal (Refereed)
    Abstract [en]

    Several lines of evidence indicate that the sarco(endo)plasmic reticulum ATPase type 2 (SERCA2) is essential for maintaining myocardial calcium handling and cardiac pump function. Hence, a reduction in SERCA2 abundance is expected to reduce work performance and maximal oxygen uptake (VO2max) and to limit the response to exercise training. To test this hypothesis, we compared VO2max and exercise capacity in mice with cardiac disruption of Serca2 (SERCA2 KO) with control mice (SERCA2 FF). We also determined whether the effects on VO2max and exercise capacity could be modified by high-intensity aerobic exercise training. Treadmill running at 85-90% of VO2max started 2 wk after Serca2 gene disruption and continued for 4 wk. VO2max and maximal running speed were measured weekly in a metabolic chamber. Cardiac function was assessed by echocardiography during light anesthesia. In sedentary SERCA2 KO mice, the aerobic capacity was reduced by 50% and running speed by 28%, whereas trained SERCA2 KO mice were able to maintain maximal running speed despite a 36% decrease in VO2max. In SERCA2 FF mice, both VO2max and maximal running speed increased by training, while no changes occurred in the sedentary group. Left ventricle dimensions remained unchanged by training in both genotypes. In contrast, training induced right ventricle hypertrophy in SERCA2 KO mice. In conclusion, the SERCA2 protein is essential for sustaining cardiac pump function and exercise capacity. Nevertheless, SERCA2 KO mice were able to maintain maximal running speed in response to exercise training despite a large decrease in VO2max.

  • 21.
    Ericsson, Madelene
    et al.
    Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
    Sjåland, Cecilie
    Andersson, Kristin B
    Sjaastad, Ivar
    Christensen, Geir
    Sejersted, Ole M
    Ellingsen, Øyvind
    Exercise training before cardiac-specific Serca2 disruption attenuates the decline in cardiac function in mice2010In: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 109, no 6, p. 1749-1755Article in journal (Refereed)
    Abstract [en]

    In the heart, function of the sarco(endo)plasmic Ca(2+)-ATPase (SERCA2) is closely linked to contractility, cardiac function, and aerobic fitness. SERCA2 function can be increased by high-intensity interval training, whereas reduced SERCA2 abundance is associated with impaired cardiac function. The working hypothesis was, therefore, that exercise training before cardiomyocyte-specific disruption of the Serca2 gene would delay the onset of cardiac dysfunction in mice. Before Serca2 gene disruption by tamoxifen, untreated SERCA2 knockout mice (Serca2(flox/flox) Tg-αMHC-MerCreMer; S2KO), and SERCA2 FF control mice (Serca2(flox/flox), S2FF) were exercise trained by high-intensity interval treadmill running for 6 wk. Both genotypes responded to training, with comparable increases in maximal oxygen uptake (Vo(2max); 17%), left ventricle weight (15%), and maximal running speed (40%). After exercise training, cardiac-specific Serca2 gene disruption was induced in both exercise trained and sedentary S2KO mice. In trained S2KO, cardiac function decreased less rapidly than in sedentary S2KO. Vo(2max) remained higher in trained S2KO the first 15 days after gene disruption. Six weeks after Serca2 disruption, cardiac output was higher in trained compared with sedentary S2KO mice. An exercise-training program attenuates the decline in cardiac performance induced by acute cardiac Serca2 gene disruption, indicating that mechanisms other than SERCA2 contribute to the favorable effect of exercise training.

  • 22.
    Forsgren, Sture
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Recent studies using an overuse animal model show that signal substances are highly involved in muscle derangement and muscle inflammation2013In: Proceedings of the International Congress on Sports Science Research and Technology Support / [ed] Jan Cabri, Pedro Pezarat Correia, João Barreiros, SciTePress, 2013, Vol. 1, p. 64-70p. 64-70Conference paper (Other academic)
    Abstract [en]

    Muscle overuse is a frequent condition accompanying sports-related activities. There is a lack of knowledge concerning the importance of signal substances in situations when overuse leads to markedly affected muscle structure and muscle inflammation. Recent observations on signal substance systems for the muscle tissue in situations with muscle overuse, noted via the use of a rabbit model, are therefore here focused on. The signal substance systems are the tachykinin system, the TNF-alpha system and the glutamate system. The studies have shown that all three systems are involved in the myositis/muscle derangement processes that occur. A central finding is the notion that signal substances in all three systems become locally produced in the muscle tissue and that there is a marked presence of receptors for these in the inflammatory/affected muscle tissue. The relevance of the findings in relation to what is known for the systems and possibilities in treatment regimens are discussed. Th e findings suggest that signal substances, more than what has been previously considered, should be taken into consideration as factors of relevance in situations when overuse leads to structural derangement and muscle inflammation.

  • 23.
    Gharibyan, Anna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Amyloids here, amyloids there…What’s wrong with them?2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Amyloid formation is inherent property of proteins which under certain circumstances can become a pathologic feature of a group of diseases called amyloidosis. There are about 30 known human amyloidosis and more than 27 identified proteins involved in these pathologies.  Besides these proteins, there are a growing number of proteins non-related to diseases shown to form amyloid-like structures in vitro, which make them excellent tools for studying amyloid formation mechanisms, physicochemical properties of different amyloid species and the nature of their influence on tissues and cells.  It is important to understand the mechanisms by which amyloids interact with different types of cells, as the leading hypothesis in amyloid field suggests that amyloids and especially their intermediate states are the main harmful, toxic species causing tissue and cell degeneration.

    Using de-novo synthesized protein albebetin as a model of amyloidogenic protein, we demonstrated that it forms amyloid-like structures under physiological conditions (pH 7 and 37°C). During aggregation it forms 2 different types of intermediate oligomers — cross-b sheet containing and lacking β-sheet oligomers. Only the former induces cellular toxicity in a dose dependent manner. Further aggregation leads to the formation of fully mature amyloid-like fibrils, which are not toxic to the cells during studied period of incubation.

    Another model protein in our studies was hen egg white lysozyme, which readily forms amyloid under denaturing conditions (pH 2,2 and 57°C). In contrast to albebetin and many other proteins reported in the literature, we showed that both oligomers and mature fibrils from hen lysozyme affect cell viability. Targeting different mechanisms involved in cellular death, we revealed that oligomers induce slow and apoptotic-like cell death, while mature fibrils cause rapid and mainly necrotic-like cellular death.   

    One of the important aspects of amyloid studies is to develop measures for inhibiting or re-directing the process of amyloid formation to abolish or neutralize toxic amyloid species. Among the agents having inhibitory or modulatory properties small, phenol containing molecules are widely studied. We investigated the effect of the novel nootropic drug noopept on amyloid formation process of α-synuclein, as this drug is a small dipeptide containing a phenol ring. We showed that noopept is able to modulate amyloid formation process by accelerating it to rapid conversion of α-synuclein into fully mature fibrils, thus eliminating the stage of population of toxic oligomeric species.  Using wide range of cytotoxicity assays we showed that amyloid-like fibrils formed in the presence of noopept have no cytotoxic properties.  As this medicine is becoming popular and freely available in some countries as a cognitive enhancer, neuroprotective and nootropic agent, further detailed investigations and clinical trials are needed to assess the safety and benefit of noopept in particular for the patients with amyloid related neurodegenerative diseases (such as Parkinson’s or Alzheimer’s diseases).    

    While in vitro models are useful to study some specific aspects of protein aggregation, their properties and effects on cell viability, it is very difficult or practically impossible to create an absolutely accurate model of in vivo situation. Therefore, it is important to turn to in vivo/ex vivo studies to relate the knowledge accumulated from in vitro studies to the real situation in the body.

    Using human brain hippocampus tissues from individuals with Alzheimer’s disease, we found that besides well-known and widely accepted main pathological hallmark — Ab peptide deposition, S100A9 and S100A8 pro-inflammatory calcium-binding proteins are also localized in the plaques and in surrounding tissues and very explicitly co-localized with Ab. Moreover, we found the presence of S100A9 within the neuronal cells, which has not been reported before and can be an important clue for understanding the mechanisms of neurodegeneration. In vitro cytotoxicity studies showed that S100A9 protein can efficiently induce cytotoxicity when added exogenously to the neuronal cell culture. These findings suggest that S100A8 and S100A9 proteins play an important role in Alzheimer’s pathology, and potentially can be candidates for the amyloid plaque formation and neurodegeneration. Whether they are associated with inflammatory processes underlying the early onset of disease or produced and accumulated as a consequence of A-beta induced pathology remain to be clarified.

    We found that Alzheimer’s disease is not the only pathology associated with A-beta and S100A9 deposition in a form of plaques. Immunohistochemical studies of an aortic valve surgically removed from a patient with aortic stenosis revealed plaque-like structures positively stained with A-beta and S100A9 proteins. These areas are also positively stained with fibril-specific antibodies as well as with Congo red, which also shows very distinct apple-green birefringence under the polarized light. Besides, there is intracellular localization and co-localization of both proteins in interstitial cells throughout the whole fibrous tissue of the valve. The presented case report is the first finding suggesting inflammatory protein S100A9 as well as A-beta peptide as potential candidates for amyloid formation in aortic stenosis valves.  We suggest that there is a specific interaction between A-beta and S100A9 during amyloid formation, which can be involved in amyloid-associated pathology in various tissues and organs in the body, which can potentially be caused by inflammatory processes, particularly by its chronic, long lasting forms.

  • 24. Golyakov, A M
    et al.
    Shchukarev, Andrey V
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Pak, V N
    Shagisultanova, G A
    Borisov, A N
    Electrochemical Synthesis and Spectroscopy of the Polymeric Form of N,N '-Bis(3-methoxysalicylidene)-1,3-propylenediamine2011In: Russian journal of applied chemistry, ISSN 1070-4272, E-ISSN 1608-3296, Vol. 84, no 2, p. 317-324Article in journal (Refereed)
    Abstract [en]

    Electrochemical oxidation of N,N '-bis(3-methoxysalicylidene)-1,3-propylenediamine leads to the formation of a conducting polymer on the electrode surface. The diffusion coeffi cient and activation barrier of the charge transfer in the bulk of the polymer in an electrolyte medium were determined. The Schiff base and its polymeric form in the oxidized and reduced states were characterized by IR, X-ray photoelectron, and electronic absorption spectroscopy. Reversible changes in the polymer structure, accompanying its electrochemical oxidation–reduction, are substantiated.

  • 25. Gruden, Marina A
    et al.
    Davydova, Tatiana V
    Narkevich, Victor B
    Fomina, Valentina G
    Wang, Chao
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Kudrin, Vladimir S
    Morozova-Roche, Ludmilla A
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Sewell, Robert D E
    Noradrenergic and serotonergic neurochemistry arising from intranasal inoculation with α-synuclein aggregates which incite parkinsonian-like symptoms2015In: Behavioural Brain Research, ISSN 0166-4328, E-ISSN 1872-7549, Vol. 279, p. 191-201Article in journal (Refereed)
    Abstract [en]

    Alpha-synuclein (α-syn) toxic aggregates delivered by the nasal vector have been shown to modify the neurochemistry of dopamine (DA) which is associated with parkinsonian-like motor symptoms. The aim was therefore to study the intranasal effects of α-syn oligomers, fibrils or their combination on the motor behavior of aged mice in relation to possible noradrenergic and serotonergic correlates. In vitro generated α-syn oligomers and fibrils were verified using atomic force microscopy and the thioflavin T binding assay. Levels of noradrenaline (NA), serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were detected using HPLC with electrochemical detection in the substantia nigra (SN) and striatum. The oligomers or fibrils administered alone or in a 50:50 combination (total dose of 0.48mg/kg) were given intranasally for 14 days and "open-field" behaviour was tested on days 0, 15 and 28 of the protocol, at which time brain structures were sampled. Behavioral deficits at the end of the 14-day dosing regime and on day 28 (i.e. 14 days after treatment completion) induced hypokinesia and immobility whilst the aggregate combination additionally produced rigidity. The α-Syn oligomer/fibril mixture also instigated PD-like motor symptoms which correlated heterochronically with elevated NA levels in the striatum but then later in the SN while intranasal fibrils alone augmented 5-HT and 5-HIAA nigral concentrations throughout the protocol. In contrast, α-syn oligomers displayed a delayed serotonin upsurge in the SN. Neurodegenerative and/or actions on neurotransmitter transporters (such as NET, SERT and VMAT2) are discussed as being implicated in these α-syn amyloid induced neurochemical and motoric disturbances.

  • 26.
    Hadrévi, Jenny
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Applying proteomics and metabolomics for studying human skeletal muscle with a focus on chronic trapezius myalgia2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Work related musculoskeletal disorders are the dominating causes of reported ill-health in industrialized countries. These chronic pain conditions are one of the most costly public health problems in Europe and North America. When work related musculoskeletal disorders are considered to be of muscular origin and the trapezius muscle is affected, the common appellation is trapezius myalgia. Since little is known about the genesis or how it is maintained, it is of great importance to better understand the pathophysiology of trapezius myalgia; doing so will better enable recommendations for prevention, treatment and rehabilitation. Several hypotheses have been presented based on biochemical alterations in the muscle, suggesting increased signaling of inflammatory substances and altered metabolism. Previous research has not been able to present the comprehensive picture of the muscle in pain. Thus there is a demand for more comprehensive research regarding the biochemical milleu of the chronic trapezius muscle.

    Proteomic and metabolomic methods allow non-targeted simultaneous analyses of a large number of proteins and metabolites. The main emphasis in this thesis is on a proteomic method, two-dimensional differential gel electrophoresis (2D-DIGE). The method is validated to human skeletal muscle biopsy research with laboratory specific settings. In the baseline study, there were 14 metabolic, contractile, structural and regulatory proteins that differed significantly in abundance when trapezius and vastus lateralis muscles were compared. Using the validated 2D-DIGE method and the baseline study, a comparison between healthy and myalgic muscles was made. Biopsies from female cleaners with and without myalgia were compared to obtain results from women with the same type of work exposure. In the multivariate model, 28 identified unique proteins separated healthy and myalgic muscle and were grouped according to function: metabolic (n=10), contractile (n=9), regulatory (n=3), structural (n=4), and other (n=2). Finally, a second screening method, metabolomics, was introduced to analyze differences in metabolite content as a complement to and verification of the proteomic results. Gas chromatography-mass spectrometry (GC-MS) was performed on muscle interstitial fluid samples obtained with microdialysis, and differences in the abundance of extracellular metabolites were revealed.

     The 2D-DIGE method is a reliable method to analyze human skeletal muscle. The outcomes of the proteomic analyses were dependant on the statistical approach. Systematic differences in protein and metabolite content were detected using a multivariate approach. Univariate analyses were used to analyze individual proteins for their significance. The significant proteins in the baseline study were predominately related to muscle fiber type which correlated with the differences in fiber type content between trapezius and vastus lateralis. The proteomic and metabolomics studies where myalgic and healthy muscles were compared provide us with new clues and new aspects regarding the pathophysiology of the myalgic muscle.

    Technically advanced methods employed in the thesis enabled an explorative screening of proteins of relevance for the pathophysiology of the myalgic muscle. The results of these analyses may contribute to the formulation of future hypothesis that need to be further evaluated.

  • 27.
    Hadrévi, Jenny
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Ghafouri, Bijar
    Rehabilitation Medicine, Department of Medicine and Health Sciences (IMH), Faculty of Health Sciences, Linköping University and Pain and Rehabilitation Centre, County Council of Östergötland, SE 581 85 Linköping, Sweden.
    Sjörs, Anna
    Rehabilitation Medicine, Department of Medicine and Health Sciences (IMH), Faculty of Health Sciences, Linköping University and Pain and Rehabilitation Centre, County Council of Östergötland, SE 581 85 Linköping, Sweden; Institute of Stress Medicine, Carl Skottsbergs gata 22B, SE 41319 Gothenburg, Sweden.
    Antti, Henrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Larsson, Britt
    Rehabilitation Medicine, Department of Medicine and Health Sciences (IMH), Faculty of Health Sciences, Linköping University and Pain and Rehabilitation Centre, County Council of Östergötland, SE 581 85 Linköping, Sweden.
    Crenshaw, A. G.
    Centre for Musculoskeletal Research, Department of Occupational and Public Health Sciences, Faculty of Health and Occupational Studies , University of Gävle, Umeå, Sweden.
    Gerdle, Björn
    Rehabilitation Medicine, Department of Medicine and Health Sciences (IMH), Faculty of Health Sciences, Linköping University and Pain and Rehabilitation Centre, County Council of Östergötland, SE 581 85 Linköping, Sweden.
    Hellström, Fredrik
    Centre for Musculoskeletal Research, Department of Occupational and Public Health Sciences, Faculty of Health and Occupational Studies , University of Gävle, Umeå, Sweden.
    Comparative metabolomics of muscle interstitium fluid in human trapezius myalgia: an in vivo microdialysis study2013In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 113, no 12, p. 2977-2989Article in journal (Other academic)
    Abstract [en]

    The mechanisms behind trapezius myalgia are unclear. Many hypotheses have been presented suggesting an altered metabolism in the muscle. Here, muscle microdialysate from healthy and myalgic muscle is analysed using metabolomics. Metabolomics analyse a vast number of metabolites, enabling a comprehensive explorative screening of the cellular processes in the muscle.

    Microdialysate samples were obtained from the shoulder muscle of healthy and myalgic subjects that performed a work and stress test. Samples from the baseline period and from the recovery period were analysed using gas chromatography-mass spectrometry (GC-MS) together with multivariate analysis to detect differences in extracellular content of metabolites between groups. Systematic differences in metabolites between groups were identified using multivariate analysis and orthogonal partial least square discriminate analysis (OPLS-DA). A complementary Mann-Whitney U test of group difference in individual metabolites was also performed.

    A large number of metabolites were detected and identified in this screening study. At baseline, no systematic differences between groups were observed according to the OPLS-DA. However, two metabolites, l-leucine and pyroglutamic acid, were significantly more abundant in the myalgic muscle compared to the healthy muscle. In the recovery period, systematic difference in metabolites between the groups was observed according to the OPLS-DA. The groups differed in amino acids, fatty acids and carbohydrates. Myristic acid and putrescine were significantly more abundant and beta-d-glucopyranose was significantly less abundant in the myalgic muscle.

    This study provides important information regarding the metabolite content, thereby presenting new clues regarding the pathophysiology of the myalgic muscle.

  • 28.
    Hammarsten, Peter
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Winther, Johanna
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Pharmacology.
    Rudolfsson, Stina H
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Urology and Andrology.
    Häggström, Jenny
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Karalija, Amar
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Egevad, Lars
    Department of Pathology and Cytology, Karolinska University Hospital, Stockholm.
    Granfors, Torvald
    Department of Urology, Central Hospital, Västerås, Sweden.
    Fowler, Christopher
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Pharmacology.
    ErbB2 Receptor Immunoreactivity in Prostate Cancer: Relationship to the Androgen Receptor, Disease Severity at Diagnosis and Disease Outcome2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 9, article id e105063Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: ErbB2 is a member of the epidermal growth factor family of tyrosine kinases that is centrally involved in the pathogenesis of prostate cancer and several studies have reported that a high expression of this protein has prognostic value. In the present study, we have investigated whether tumour ErbB2 immunoreactivity (ErbB2-IR) has clinically useful prognostic value, i.e. that it provides additional prognostic information to that provided by routine clinical tests (Gleason score, tumour stage).

    METHODOLOGY/PRINCIPAL FINDINGS: ErbB2-IR was measured in a well-characterised tissue microarray of tumour and non-malignant samples obtained at diagnosis. Additionally, mRNA levels of ErbB2-IR in the prostate were determined in the rat following manipulation of circulating androgen levels. Tumour ErbB2-IR was significantly associated with the downstream signalling molecule phosphorylated-Akt and with the cell proliferation marker Ki-67. The significant association of tumour ErbB2-IR with the Gleason score at diagnosis was lost when controlled for the association of both parameters with Ki-67. In the rat prostate, mRNA for ErbB2 was inversely associated with circulating androgen levels. There was no association between ErbB2-IR and the androgen receptor (AR)-IR in the tumours, but an interaction between the two parameters was seen with respect to their association with the tumour stage. Tumour ErbB2-IR was confirmed to be a prognostic marker for disease-specific survival, but it did not provide significant additive information to the Gleason score or to Ki-67.

    CONCLUSIONS/SIGNIFICANCE: It is concluded that tumour ErbB2-IR is of limited clinical value as a prognostic marker to aid treatment decisions, but could be of pathophysiological importance in prostate cancer.

  • 29.
    Hellström, Sten
    et al.
    Department of CLINTEC/Otorhinolaryngology, Karolinska Medical University.
    Shen, Yue
    University of British Columbia.
    Ny, Tor
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    A reply to the commentary on "Animal models of chronic tympanic membrane perforation: in response to plasminogen initiates and potentiates the healing of acute and chronic tympanic membrane perforations in mice" by Wang AY, Shen Y, Wang JT, Eikelboom RH and Dilley RJ; Clin Translat Med, 2014; 32015In: Clinical and translational medicine, ISSN 2001-1326, Vol. 4, no 8Article in journal (Refereed)
  • 30. Hepburn, Lucy
    et al.
    Prajsnar, Tomasz K
    Klapholz, Catherine
    Moreno, Pablo
    Loynes, Catherine A
    Ogryzko, Nikolay V
    Brown, Karen
    Schiebler, Mark
    Hegyi, Krisztina
    Antrobus, Robin
    Hammond, Katherine L
    Connolly, John
    Ochoa, Bernardo
    Bryant, Clare
    Otto, Michael
    Surewaard, Bas
    Seneviratne, Suranjith L
    Grogono, Dorothy M
    Cachat, Julien
    Ny, Tor
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Kaser, Arthur
    Török, M Estée
    Peacock, Sharon J
    Holden, Matthew
    Blundell, Tom
    Wang, Lihui
    Ligoxygakis, Petros
    Minichiello, Liliana
    Woods, C Geoff
    Foster, Simon J
    Renshaw, Stephen A
    Floto, R Andres
    A Spaetzle-like role for nerve growth factor beta in vertebrate immunity to Staphylococcus aureus2014In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 346, no 6209, p. 641-646Article in journal (Refereed)
    Abstract [en]

    Many key components of innate immunity to infection are shared between Drosophila and humans. However, the fly Toll ligand Spaetzle is not thought to have a vertebrate equivalent. We have found that the structurally related cystine-knot protein, nerve growth factor β (NGFβ), plays an unexpected Spaetzle-like role in immunity to Staphylococcus aureus infection in chordates. Deleterious mutations of either human NGFβ or its high-affinity receptor tropomyosin-related kinase receptor A (TRKA) were associated with severe S. aureus infections. NGFβ was released by macrophages in response to S. aureus exoproteins through activation of the NOD-like receptors NLRP3 and NLRP4 and enhanced phagocytosis and superoxide-dependent killing, stimulated proinflammatory cytokine production, and promoted calcium-dependent neutrophil recruitment. TrkA knockdown in zebrafish increased susceptibility to S. aureus infection, confirming an evolutionarily conserved role for NGFβ-TRKA signaling in pathogen-specific host immunity.

  • 31.
    Hillgren, Mikael J
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Dahlgren, Markus K
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    To, Tam M
    Elofsson, Mikael
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Synthesis of [4-(2-Hydroxyphenyl)thiazol-2-yl]methanones as Potential Bioisosteres of Salicylidene Acylhydrazides2010In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 15, no 9, p. 6019-34Article in journal (Refereed)
    Abstract [en]

    A focused library of [4-(2-hydroxyphenyl)thiazol-2-yl]methanones was prepared in a four-step synthesis with the aim to obtain potent inhibitors of type III secretion in Gram-negative bacteria. The compounds are potential bioisosteres of salicylidene acylhydrazides that are a known class of type III secretion inhibitors.

  • 32.
    Hofer, Per-Åke
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Urbach-Wiethe disease1974Doctoral thesis, comprehensive summary (Other academic)
  • 33. Honkanen, Juuso
    et al.
    Turunen, Mikael
    Freedman, Jonathan
    Saarakkala, Simo
    Grinstaff, Mark
    Ylärinne, Janne
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Jurvelin, Jukka
    Töyräs, Juha
    Cationic contrast agent diffusion differs between cartilage and meniscus2016In: Annals of Biomedical Engineering, ISSN 0090-6964, E-ISSN 1573-9686, Vol. 44, no 10, p. 2913-2921Article in journal (Refereed)
    Abstract [en]

    Contrast enhanced computed tomography (CECT) is a non-destructive imaging technique used for the assessment of composition and structure of articular cartilage and meniscus. Due to structural and compositional differences between these tissues, diffusion and distribution of contrast agents may differ in cartilage and meniscus. The aim of this study is to determine the diffusion kinematics of a novel iodine based cationic contrast agent (CA(2+)) in cartilage and meniscus. Cylindrical cartilage and meniscus samples (d = 6 mm, h ≈ 2 mm) were harvested from healthy bovine knee joints (n = 10), immersed in isotonic cationic contrast agent (20 mgI/mL), and imaged using a micro-CT scanner at 26 time points up to 48 h. Subsequently, normalized X-ray attenuation and contrast agent diffusion flux, as well as water, collagen and proteoglycan (PG) contents in the tissues were determined. The contrast agent distributions within cartilage and meniscus were different. In addition, the normalized attenuation and diffusion flux were higher (p < 0.05) in cartilage. Based on these results, diffusion kinematics vary between cartilage and meniscus. These tissue specific variations can affect the interpretation of CECT images and should be considered when cartilage and meniscus are assessed simultaneously.

  • 34.
    Hörnblad, Andreas
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Imaging the pancreas: new aspects on lobular development and adult constitution2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The mouse pancreas is a mixed exocrine and endocrine glandconsisting of three lobular compartments: the splenic, duodenal and gastric lobes. During embryogenesis, the pancreas forms from two progenitor populations located on the dorsal and ventral side of the primitive gut tube. These anlagen are brought in close proximity as the gut elongates and rotates, and fuse to form a single organ. The splenic and duodenal lobes develop from the dorsal and ventral anlagen, respectively.

    In the adult pancreas, exocrine tissue secretes digestive enzymes intothe gut lumen to support nutrient uptake. The endocrine Islets of Langerhans are scattered throughout the exocrine tissue and aid in regulation of energy homeostasis through the secretion of hormones. One of the key players in energy homeostasis is the pancreatic ß-cell, which is the most abundant cell type of the islets. The β-cells regulates blood glucose levels through the action of insulin. Conditions where this regulation does not function properly are gathered under the common name of Diabetes mellitus.

    Type 1 diabetes (T1D) is characterized by insulin deficiency due to autoimmune destruction of the ß-cells. Using recently developed protocols for optical projection tomography (OPT) whole-organ imaging, we have revealed new spatial and quantitative aspects on ß-cell mass dynamics and immune infiltration during the course of T1D development in the non-obese diabetic (NOD) mouse model. We show that although immune infiltration appears to occur asynchronously throughout the organ, smaller islets, mainly located in the periphery of the organ, preferentially loose their ß-cells during early stages of disease progression. Larger islets appear more resistant to the autoimmune attack and our data indicate the existence of a compensatory proliferative capacity within these islets. We also report the appearance of structures resembling tertiary lymphoid organs (TLOs) in association with the remaining islets during later phases of T1D progression.

    OPT has already proven to be a useful tool for assessments of ß-cellmass in the adult mouse pancreas. However, as with other techniques, previous protocols have relied on a tedious degree of manual postivacquisition editing. To further refine OPT-based assessment of pancreatic ß-cell mass distribution in the murine pancreas, we implemented a computational statistical approach, Contrast-Limited Adaptive Histogram Normalisation (CLAHE), to the OPT projection data of pancreata from C57Bl/6 mice. This methodology provided increased islet detection sensitivity, improved islet morphology and diminished subjectivity in thresholding for reconstruction and quantification. Using this approach, we could report a substantially higher number of islets than previously described for this strain and provide evidence of significant differences in islet mass distribution between the pancreatic lobes. The gastric lobe stood out in particular and contained a 75% higher islet density as compared to the splenic lobe.

    Although the development of the early pancreatic buds has been relatively well studied, later morphogenetic events are less clear and information regarding the formation of the gastric lobe has largely been missing. Using OPT we have generated a quantitative three-dimensional road map of pancreatic morphogenesis in the mouse. We show that the gastric lobe forms as a perpendicular outgrowth fromthe stem of the dorsal pancreas at around embryonic day (e) 13.5, which grows into a mesenchymal domain overlaying the pyloric sphincter and proximal part of the glandular stomach. By analyzing mutant mice with aberrant spleen development, we further demonstrate that proper formation of the gastric lobe is dependent on the initial formation of the closely positioned spleen, indicating a close interplay between pancreatic and splenic mesenchyme during development. Additionally, we show that the expression profile of markers for pancreatic multipotent progenitors within the pancreas is heterogenous with regards to lobular origin. Altogether, our studies regarding the morphogenesis and adult constitution of the mouse pancreas recognize lobular heterogeneities that add important information for future interpretations of this organ.

  • 35.
    Iakovleva, Irina
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Selection of transthyretin amyloid inhibitors2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Amyloidosis is a group of clinical disorders caused by the aggregation of specific proteins into abnormal extracellular deposits. Today, 31 different proteins have been linked to amyloid diseases including transthyretin-related amyloidosis (ATTR). ATTR occurs through the aggregation of either wild-type plasma protein transthyretin (TTR) or a mutated form. TTR is a homotetramer that under normal circumstances functions as a carrier of thyroxine and retinol binding protein. The aggregation cascade requires dissociation of the tetramer into monomers, and preventing this dissociation represents a potential mode of intervention. Interestingly, small molecules, referred as kinetic stabilizers, can bind to TTR’s thyroxine-binding site (TBS) and such molecules are currently being used as a therapeutic approach to impair tetramer dissociation.

    The efficacy of TTR stabilization is directly correlated to the binding affinity of the ligand to TBS. However, the binding of the ligand to TTR in vivo can be affected by other plasma components resulting in poor efficacy. Thus, the selectivity of ligands is an important parameter. We have designed an assay where the ability to stabilize TTR can be directly evaluated in plasma and we have investigated the stabilizing effect of nine potential TTR binders (Paper I). The results, surprisingly, revealed that the binding affinity of molecules has a poor correlation to its selectivity. However, the nature of protein-ligand complex formation can also be described by enthalpic (∆H) and entropic (∆S) energy contributions. ∆H represents the change in chemical bonds and frequently requires a higher order of orientation compared to the ∆S component, which mainly represents the hydrophobic effect via the exclusion of water. We hypothesized that ligands possessing high ΔH in binding to their co-partner would also be more specific in a complex environment such as plasma. By applying a thermodynamic analysis using isothermal titration calorimetry, we found that the selectivity in plasma correlates well with the ∆H contribution and might, therefore, be a better predictor for selectivity.

    Luteolin was found to be a highly selective stabilizer of TTR and was investigated further (Paper II). The ligand displayed a significant rescuing effect in both cell culture and animal models. However, luteolin undergoes rapid enzymatic degradation in the liver and this impairs its use as a potential therapeutic drug. To attempt to circumvent this issue, we modified the most exposed hydroxyl group thus rendering the molecule inert towards glucuronidation (Paper III). The substitutions resulted in higher stability in the face of hepatic degradation molecules, but they also affected the selectivity in a negative manner.

    The screening for new TTR stabilizers resulted in the discovery of tetrabromobisphenol A, which displayed a very high selectivity (Paper IV). This study also included a comparison with the drug Vyndaqel™ which currently is in clinically use, and showed how the dosage could be altered to acquire a better level of saturation and possibly also a better clinical effect.

    Taken together we present new molecules with the ability to stabilize TTR, and these can serve as scaffolds for the design of new drugs. We present a method to measure the efficacy of a TTR-stabilizing drugs in a complex matrix and as well as a way to adjust the dosage of existing drugs. We also show that the selectivity of a drug is affected by the relative proportion of ∆H and ∆S, and this is of interest for drug design in general.

  • 36.
    Jernberg, Emma
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Mechanisms behind growth of castration-resistant prostate cancer bone metastases2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background: The first-line treatment for patients with advanced prostate cancer (PC) is androgen deprivation therapy. This therapy is initially effective, but after some time tumors relapse, predominantly within the bone, and are then termed castration-resistant prostate cancer (CRPC). The majority of CRPC tumors show androgen receptor (AR) activity despite castrate levels of circulating testosterone. AR activity could be caused by several mechanisms including; intratumoral androgen synthesis, AR amplification, AR mutations and expression of AR splice variants. The mechanisms controlling CRPC growth in the clinically most relevant metastatic site, the bone, are not fully identified. The purpose of this thesis was therefore to explore AR expression and possible mechanisms behind CRPC growth in PC bone metastases in order to find mechanisms that could be targeted for treatment and/or predict response to certain therapies.

    Materials and Methods: We have examined hormone-naïve and CRPC bone metastases samples obtained from patients at metastasis surgery, non-malignant and malignant prostate samples obtained from patients at radical prostatectomy, and PC cell lines cultured in vitro. Analysis has been performed using RT-PCR, whole-genome expression arrays, immunohistochemistry, western blotting, FISH, copy number assays and gene ontology analysis. Functional studies have been made by protein overexpression and knock-down in PC cells in vitro and effects studied by evaluation of cell viability, migration, and invasion.

    Results: We found that high nuclear AR immunostaining (presumed to reflect high AR activity) in bone metastases from CRPC patients was associated with a particularly poor prognosis, while no difference in AR staining was observed between hormone-naïve and CRPC metastases. Further, expression of AR splice variants (AR-V7, AR-V567es) was associated with a high nuclear AR immunostaining score and shown to be increased in CRPC compared to hormone-naïve bone metastases. High levels (levels in the upper quartile) of AR splice variants in CRPC bone metastases was related to disturbed cell cycle regulation and short patients survival. No differences in steroidogenic enzyme levels were detected between CRPC and hormone-naïve bone metastases. Higher levels of enzymes involved in late steps of androgen synthesis (adrenal gland steroid conversion) were observed in bone metastases than in non-malignant and/or malignant prostate tissue, while the enzyme levels in earlier steps (de novo steroidogenesis) were lower in bone metastases. A subgroup of metastases expressed very high levels of AKR1C3, indicating that this group may have an induced capacity of converting adrenal-gland derived steroids into more potent androgens. This was not associated to CRPC but merely with the advanced stage of metastasis. High protein levels of AR splice variants were found in bone metastases with low AKR1C3 levels, while metastases with high AKR1C3 levels primarily contained low AR variant levels. Furthermore, about half of the CRPC bone metastases showed androgen receptor gene amplification which was associated with co-amplification of YIPF6, and a gene expression pattern that pointed at decreased osteoclast activity, and consequently decreased bone resorption.

    Conclusions: The majority of CRPC bone metastases show high nuclear AR immunostaining that seems to be associated with a particularly unfavorable outcome after metastasis surgery. Subgroups of CRPC bone metastases could be identified according to presence of AR amplification and expression levels of AKR1C3 or AR splice variants, which might have clinical relevance for treatment of PC patients.

  • 37.
    Jones, Iwan
    et al.
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Hägglund, Anna-Carin
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Törnqvist, Gunilla
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Nord, Christoffer
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Ahlgren, Ulf
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Carlsson, Leif
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    A novel mouse model of tuberous sclerosis complex (TSC): eye-specific Tsc1-ablation disrupts visual-pathway development2015In: Disease Models and Mechanisms, ISSN 1754-8403, E-ISSN 1754-8411, Vol. 8, no 12, p. 1517-1529Article in journal (Refereed)
    Abstract [en]

    Tuberous sclerosis complex (TSC) is an autosomal dominant syndrome that is best characterised by neurodevelopmental deficits and the presence of benign tumours (called hamartomas) in affected organs. This multi-organ disorder results from inactivating point mutations in either the TSC1 or the TSC2 genes and consequent activation of the canonical mammalian target of rapamycin complex 1 signalling (mTORC1) pathway. Because lesions to the eye are central to TSC diagnosis, we report here the generation and characterisation of the first eye-specific TSC mouse model. We demonstrate that conditional ablation of Tsc1 in eye-committed progenitor cells leads to the accelerated differentiation and subsequent ectopic radial migration of retinal ganglion cells. This results in an increase in retinal ganglion cell apoptosis and consequent regionalised axonal loss within the optic nerve and topographical changes to the contra- and ipsilateral input within the dorsal lateral geniculate nucleus. Eyes from adult mice exhibit aberrant retinal architecture and display all the classic neuropathological hallmarks of TSC, including an increase in organ and cell size, ring heterotopias, hamartomas with retinal detachment, and lamination defects. Our results provide the first major insight into the molecular etiology of TSC within the developing eye and demonstrate a pivotal role for Tsc1 in regulating various aspects of visual-pathway development. Our novel mouse model therefore provides a valuable resource for future studies concerning the molecular mechanisms underlying TSC and also as a platform to evaluate new therapeutic approaches for the treatment of this multi-organ disorder.

  • 38.
    Jonsson, Samuel
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Wiberg, Rebecca
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    McGrath, Aleksandra M
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy. Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Novikov, Lev N
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Wiberg, Mikael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy. Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Novikova, Liudmila N
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Kingham, Paul J
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Effect of delayed peripheral nerve repair on nerve regeneration, Schwann cell function and target muscle recovery2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 2, article id e56484Article in journal (Refereed)
    Abstract [en]

    Despite advances in surgical techniques for peripheral nerve repair, functional restitution remains incomplete. The timing of surgery is one factor influencing the extent of recovery but it is not yet clearly defined how long a delay may be tolerated before repair becomes futile. In this study, rats underwent sciatic nerve transection before immediate (0) or 1, 3, or 6 months delayed repair with a nerve graft. Regeneration of spinal motoneurons, 13 weeks after nerve repair, was assessed using retrograde labeling. Nerve tissue was also collected from the proximal and distal stumps and from the nerve graft, together with the medial gastrocnemius (MG) muscles. A dramatic decline in the number of regenerating motoneurons and myelinated axons in the distal nerve stump was observed in the 3- and 6-months delayed groups. After 3 months delay, the axonal number in the proximal stump increased 2-3 folds, accompanied by a smaller axonal area. RT-PCR of distal nerve segments revealed a decline in Schwann cells (SC) markers, most notably in the 3 and 6 month delayed repair samples. There was also a progressive increase in fibrosis and proteoglycan scar markers in the distal nerve with increased delayed repair time. The yield of SC isolated from the distal nerve segments progressively fell with increased delay in repair time but cultured SC from all groups proliferated at similar rates. MG muscle at 3- and 6-months delay repair showed a significant decline in weight (61% and 27% compared with contra-lateral side). Muscle fiber atrophy and changes to neuromuscular junctions were observed with increased delayed repair time suggestive of progressively impaired reinnervation. This study demonstrates that one of the main limiting factors for nerve regeneration after delayed repair is the distal stump. The critical time point after which the outcome of regeneration becomes too poor appears to be 3-months.

  • 39. Kalkunte, Satyan S.
    et al.
    Neubeck, Stefan
    Norris, Wendy E.
    Cheng, Shi-Bin
    Kostadinov, Stefan
    Vu Hoang, Dang
    Ahmed, Aftab
    von Eggeling, Ferdinand
    Shaikh, Zahir
    Padbury, James
    Berg, Goran
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Markert, Udo R.
    Sharma, Surendra
    Transthyretin is dysregulated in preeclampsia, and its native form prevents the onset of disease in a preclinical mouse model2013In: American Journal of Pathology, ISSN 0002-9440, E-ISSN 1525-2191, Vol. 183, no 5, p. 1425-1436Article in journal (Refereed)
    Abstract [en]

    Preeclampsia is a major pregnancy complication with potential short- and long-term consequences for both mother and fetus. Understanding its pathogenesis and causative biomarkers is likely to yield insights for prediction and treatment. Herein, we provide evidence that transthyretin, a transporter of thyroxine and retinol, is aggregated in preeclampsia and is present at reduced levels in sera of preeclamptic women, as detected by proteomic screen. We demonstrate that transthyretin aggregates form deposits in preeclampsia placental tissue and cause apoptosis. By using in vitro approaches and a humanized mouse model, we provide evidence for a causal link between dysregulated transthyretin and preeclampsia. Native transthyretin inhibits all preeclampsia-like features in the humanized mouse model, including new-onset proteinuria, increased blood pressure, glomerular endotheliosis, and production of anti-angiogenic factors. Our findings suggest that a focus on transthyretin structure and function is a novel strategy to understand and combat preeclampsia.

  • 40. Kerje, Susanne
    et al.
    Hellman, Urban
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Do, Lan
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Larsson, Göran
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Kämpe, Olle
    Engström-Laurent, Anna
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Lindqvist, Ulla
    Is low molecular hyaluronan an early indicator of disease in avian systemic sclerosis?2016In: Connective Tissue Research, ISSN 0300-8207, E-ISSN 1607-8438, Vol. 57, no 5, p. 337-346Article in journal (Refereed)
    Abstract [en]

    AIM OF THE STUDY: To further elucidate the pathogenesis of systemic sclerosis (SSc) an experimental avian model was used. University of California at Davies line 200-chicken (UCD-200) spontaneously develops a SSc like disease that has most features of human SSc with vascular effects, inflammation, autoimmunity and fibrosis. The first signs of disease in UCD-200 are swelling and ischemic lesions of the comb, a tissue containing high amounts of the glycosaminoglycan hyaluronan. The aim was to evaluate inflammatory and fibrotic processes of the disease with regard to the molecular weight of hyaluronan.

    MATERIAL AND METHODS: Comb biopsies from UCD-200 and healthy White Leghorn (WL) chickens as controls at different ages were studied with histochemical localization of hyaluronan, hyaluronidase 1, CD3, IgY and collagen I and III. Hyaluronan molecular weight distribution was estimated with gas phase electrophoretic analysis.

    RESULTS: At 2 days of age hyaluronan was visualized in UCD-200 at the dermal part of the comb with no simultaneous staining of Hyal-1. In adult UCD-200 the comb skin was almost totally devoid of hyaluronan compared to WL of the same age. An increase of low molecular weight (LMW) hyaluronan was detected in comb tissue from UCD-200 at 1 day, 1, 2, 4 weeks in contrast to adult animals.

    CONCLUSIONS: An early inflammatory process involving LMW hyaluronan was confirmed as a possible profibrotic process. This indicates that hyaluronan might be an important participant in early inflammatory events of SSc in UCD-200 chicken and that disappearance of hyaluronan in skin predisposes to fibrosis.

  • 41. Klingenberg, Roland
    et al.
    Gerdes, Norbert
    Badeau, Robert M
    Gisterå, Anton
    Strodthoff, Daniela
    Ketelhuth, Daniel FJ
    Lundberg, Anna M
    Rudling, Mats
    Nilsson, Stefan K
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Physiological chemistry.
    Olivecrona, Gunilla
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Physiological chemistry.
    Zoller, Stefan
    Lohmann, Christine
    Luescher, Thomas F
    Jauhiainen, Matti
    Sparwasser, Tim
    Hansson, Göran K
    Depletion of FOXP3(+) regulatory T cells promotes hypercholesterolemia and atherosclerosis2013In: Journal of Clinical Investigation, ISSN 0021-9738, E-ISSN 1558-8238, Vol. 123, no 3, p. 1323-1334Article in journal (Refereed)
    Abstract [en]

    Atherosclerosis is a chronic inflammatory disease promoted by hyperlipidemia. Several studies support FOXP3-positive regulatory T cells (Tregs) as inhibitors of atherosclerosis; however, the mechanism underlying this protection remains elusive. To define the role of FOXP3-expressing Tregs in atherosclerosis, we used the DEREG mouse, which expresses the diphtheria toxin (DT) receptor under control of the Treg-specific Foxp3 promoter, allowing for specific ablation of FOXP3(+) Tregs. Lethally irradiated, atherosclerosis-prone, low-density lipoprotein receptor-deficient (Ldlr(-/-)) mice received DEREG bone marrow and were injected with DT to eliminate FOXP3(+) Tregs. Depletion of Tregs caused a 2.1-fold increase in atherosclerosis without a concomitant increase in vascular inflammation. These mice also exhibited a 1.7-fold increase in plasma cholesterol and an atherogenic lipoprotein profile with increased levels of VLDL. Clearance of VLDL and chylomicron remnants was hampered, leading to accumulation of cholesterol-rich particles in the circulation. Functional and protein analyses complemented by gene expression array identified reduced protein expression of sortilin-1 in liver and increased plasma enzyme activity of lipoprotein lipase, hepatic lipase, and phospholipid transfer protein as mediators of the altered lipid phenotype. These results demonstrate that FOXP3(+) Tregs inhibit atherosclerosis by modulating lipoprotein metabolism.

  • 42.
    Larsson, Elin
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Medical and Clinical Genetics.
    The use of monogenic disease to study basal and disease associated mechanisms with focus on NGF dependent pain insensitivity and ISCU myopathy2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Monogenic diseases make excellent models for the study of gene functions and basal cellular mechanisms in humans. The aim of this thesis was to elucidate how genetic mutations affect the basal cellular mechanisms in the monogenic diseases Nerve growth factor (NGF) dependent pain insensitivity and Iron-Sulphur cluster assembly protein U (ISCU) myopathy.

    NGF dependent pain insensitivity is a rare genetic disorder with clinical manifestations that include insensitivity to deep pain, development of Charcot joints, and impaired temperature sensation but with no effect on mental abilities. The disease is caused by a missense mutation in the NGFβ gene causing a drastic amino acid substitution (R221W) in a well-conserved region of the protein. NGF is secreted in limited amounts by its target tissues and is important for the development and maintenance of the cholinergic forebrain neurons as well as the sensory and sympathetic neurons. To reveal the underlying mechanisms of disease we performed functional studies of the mutant NGF protein. We could show that mutant NGF was unable to induce differentiation of PC12 cells as a consequence of impaired secretion. Furthermore, mutant NGF had different intracellular localisation compared to normal NGF and resided mostly in its unprocessed form proNGF. Mature NGF and proNGF have different binding properties to the receptors TrkA and p75. Individuals with mutations in TRKA are, aside from pain insensitive mentally affected; therefore it has been proposed that the R221W mutation mainly affects the interaction with p75. In agreement with this, we could show that R221W NGF was able to bind and activate TrkA whereas the interaction with p75 was impaired as compared to normal NGF.

    ISCU myopathy is a monogenic disease where the affected patients suffer from severe exercise intolerance resulting in muscle cramps and sometimes severe lactic acidosis. The disease is caused by a point mutation in the last intron of the Iron sulphur cluster assembly gene, ISCU, resulting in the inclusion of a part of the intron in the mRNA. ISCU functions as a scaffold protein in the assembly of iron-sulphur (Fe-S) clusters important for electron transport in Kreb’s cycle and the respiratory chain. We have shown that ISCU is vital in mammals since complete knock-down of Iscu in mice results in early embryonic death. The deletion of ISCU homologous in lower organisms has also been shown fatal. In spite this central role in energy metabolism the disease is restricted to the patient’s skeletal muscles while other energy demanding organs seem unaffected. To address this contradiction we examined if tissue-specific differences in the splicing of mutant ISCU could explain the muscle-specific phenotype. We could show that the splicing pattern did, indeed, differ with more incorrectly spliced ISCU in muscle compared to other tissues. This was accompanied by a decrease in Fe-S containing proteins in muscle, while no decrease was observed in other tissues. Alternative splicing is more common then previously thought and may depend upon interacting factors and/or differences in the surrounding milieu. To reveal plausible mechanisms involved in the tissue-specific splicing we identified nuclear factors that interacted with the region where the mutation was located. Five interacting factors were identified, out of which three affected the splicing of ISCU. PTBP1 was shown to repress the incorrect splicing while IGF2BP1 and RBM39 repressed the formation of normal transcript and could also counteract the effect of PTBP1. IGF2BP1 was the only factor that showed higher affinity to the mutant sequence making it a possible key factor in the incorrect splicing of the mutant ISCU gene.

    Together, these results offer important insights into the cellular mechanisms causing these diseases. We found impaired secretion and inaccurate sorting of NGF to be cellular mechanisms contributing to NGF dependent pain insensitivity while tissue-specific splicing of ISCU was found to be the event contributing to the phenotype of ISCU myopathy.

  • 43.
    Limé, Fredrik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Irgum, Knut
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Hydrobromination of residual vinyl groups on divinylbenzene polymer particles followed by atom transfer radical surface graft polymerization2009In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 47, no 5, p. 1259-1265Article in journal (Refereed)
    Abstract [en]

    Rigid and monodisperse spherical polymer particles with 2.36 ± 0.18 m diameter containing residual surface vinyl groups were prepared by photoinitiated precipitation polymerization of divinylbenzene. Anti-Markovnikov addition of HBr to the surface vinyl groups yielded a 2-bromoethyl functionality that was used as macroinitiator for atom transfer radical polymerization (ATRP), providing the possibility for further functionalization by controlled grafting from processes. This was demonstrated by grafting of glycidyl methacrylate brushes from the particle surface, using an ATRP system based on CuBr and pentamethyl diethylenetriamine. Existence of a methacrylic overlayer was verified by FTIR and XPS measurements, and the grafted particles were easily dispersed in water, confirming conversion of the particle surface from hydrophobic to hydrophilic. Hydrobromination of residual vinyl groups yields a macroinitiator that can be used for grafting of glycidyl methacrylate by ATRP.

  • 44. Lin, Chia-Yeh
    et al.
    Wu, Meng-Ying
    Gay, Sophie
    Marjavaara, Lisette
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Lai, Mong Sing
    Hsiao, Wei-Chun
    Hung, Shih-Hsun
    Tseng, Hsin-Yi
    Wright, Duncan Edward
    Wang, Chen-Yi
    Hsu, Guoo-Shyng W
    Devys, Didier
    Chabes, Andrei
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Kao, Cheng-Fu
    H2B Mono-ubiquitylation Facilitates Fork Stalling and Recovery during Replication Stress by Coordinating Rad53 Activation and Chromatin Assembly2014In: PLOS Genetics, ISSN 1553-7390, E-ISSN 1553-7404, Vol. 10, no 10, p. e1004667-Article in journal (Refereed)
    Abstract [en]

    The influence of mono-ubiquitylation of histone H2B (H2Bub) on transcription via nucleosome reassembly has been widely documented. Recently, it has also been shown that H2Bub promotes recovery from replication stress; however, the underling molecular mechanism remains unclear. Here, we show that H2B ubiquitylation coordinates activation of the intra-S replication checkpoint and chromatin re-assembly, in order to limit fork progression and DNA damage in the presence of replication stress. In particular, we show that the absence of H2Bub affects replication dynamics (enhanced fork progression and reduced origin firing), leading to γH2A accumulation and increased hydroxyurea sensitivity. Further genetic analysis indicates a role for H2Bub in transducing Rad53 phosphorylation. Concomitantly, we found that a change in replication dynamics is not due to a change in dNTP level, but is mediated by reduced Rad53 activation and destabilization of the RecQ helicase Sgs1 at the fork. Furthermore, we demonstrate that H2Bub facilitates the dissociation of the histone chaperone Asf1 from Rad53, and nucleosome reassembly behind the fork is compromised in cells lacking H2Bub. Taken together, these results indicate that the regulation of H2B ubiquitylation is a key event in the maintenance of genome stability, through coordination of intra-S checkpoint activation, chromatin assembly and replication fork progression.

  • 45.
    Lindhagen Persson, Malin
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Targeting cytotoxic species in amyloid diseases2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Amyloid diseases are a world-wide problem causing great human suffer and large economical costs. Although amyloid deposits, a common denominator in all amyloid disorders, are detrimental to the surrounding tissue, there is a poor correlation between total amyloid burden and clinical symptoms. Soluble oligomers are much more potent to exert a tissue damaging effect. 

    Alzheimer’s disease (AD) is strongly linked to self-assembly of the amyloid-β (Aβ) peptide. Antibodies selectively targeting cytotoxic Aβ-species are useful both for understanding oligomer formation and for their therapeutic abilities. We hypothesized that the effect of avidity would compensate for a low single site affinity and be enough to selectively target oligomers. To evaluate this hypothesis, we focused on the IgM isotype having ten antigen-binding sites. In accordance with the hypothesis, the IgM isotype effectively bound oligomeric Aβ also in presence of a vast excess of its monomeric counterpart, clearly illustrating the potentiating effect of avidity. As a continuation of this work, we have shown that the avidity effect from a bivalent binding is enough to induce oligomer specificity. This finding facilitates a direct application on the clinically more useful IgG isotype, where the binding properties now can be controlled in detail. The method is general and we have, using this technique, also designed oligomer specific antibodies targeting α-synuclein.

    Transthyretin (TTR) is an amyloidogenic protein involved in both hereditary and sporadic amyloidosis. The cytotoxicity of TTR is intriguing since studies have shown cytotoxic potential from oligomers, tetramers and even monomers. Elucidation of the molecular properties associated with TTR cytotoxicity is hence of interest. By preventing tetramer dissociation, TTR aggregation and TTR-induced cytotoxicity is abolished. Based on this rationale, a current therapeutic strategy is to stabilize the TTR tetramer with small molecules. The kinetic stability within the spectra of known TTR mutations spans more than three orders of magnitude. However, although the most stable mutants are inert, a poor correlation within the group of cytotoxic variants exists where the cytotoxic effect is not potentiated in proportion to their kinetic stability. Through analysis of a large spectra of TTR variants, our results indicate that TTR induced cytotoxicity requires an intermediate stability of the TTR molecule. The kinetic stability should be low enough to permit tetramer dissociation and the thermodynamic stability high enough to prevent instant aggregation and to allow formation of the cytotoxic fold. 

  • 46.
    Maicher, André
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Gazy, Inbal
    Sharma, Sushma
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Marjavaara, Lisette
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Grinberg, Gilad
    Shemesh, Keren
    Chabes, Andrei
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Kupiec, Martin
    Rnr1, but not Rnr3, facilitates the sustained telomerase-dependent elongation of telomeres2017In: PLoS Genetics, ISSN 1553-7390, E-ISSN 1553-7404, Vol. 13, no 10, article id e1007082Article in journal (Refereed)
    Abstract [en]

    Ribonucleotide reductase (RNR) provides the precursors for the generation of dNTPs, which are required for DNA synthesis and repair. Here, we investigated the function of the major RNR subunits Rnr1 and Rnr3 in telomere elongation in budding yeast. We show that Rnr1 is essential for the sustained elongation of short telomeres by telomerase. In the absence of Rnr1, cells harbor very short, but functional, telomeres, which cannot become elongated by increased telomerase activity or by tethering of telomerase to telomeres. Furthermore, we demonstrate that Rnr1 function is critical to prevent an early onset of replicative senescence and premature survivor formation in telomerase-negative cells but dispensable for telomere elongation by Homology-Directed-Repair. Our results suggest that telomerase has a "basal activity" mode that is sufficient to compensate for the "end-replication-problem" and does not require the presence of Rnr1 and a different "sustained activity" mode necessary for the elongation of short telomeres, which requires an upregulation of dNTP levels and dGTP ratios specifically through Rnr1 function. By analyzing telomere length and dNTP levels in different mutants showing changes in RNR complex composition and activity we provide evidence that the Mec1ATR checkpoint protein promotes telomere elongation by increasing both dNTP levels and dGTP ratios through Rnr1 upregulation in a mechanism that cannot be replaced by its homolog Rnr3.

  • 47. McDonald, Karin R.
    et al.
    Guise, Amanda J.
    Pourbozorgi-Langroudi, Parham
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Cristea, Ileana M.
    Zakian, Virginia A.
    Capra, John A.
    Sabouri, Nasim
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Pfh1 Is an Accessory Replicative Helicase that Interacts with the Replisome to Facilitate Fork Progression and Preserve Genome Integrity2016In: PLoS Genetics, ISSN 1553-7390, E-ISSN 1553-7404, Vol. 12, no 9, article id e1006238Article in journal (Refereed)
    Abstract [en]

    Replicative DNA helicases expose the two strands of the double helix to the replication apparatus, but accessory helicases are often needed to help forks move past naturally occurring hard-to-replicate sites, such as tightly bound proteins, RNA/DNA hybrids, and DNA secondary structures. Although the Schizosaccharomyces pombe 5'-to-3' DNA helicase Pfh1 is known to promote fork progression, its genomic targets, dynamics, and mechanisms of action are largely unknown. Here we address these questions by integrating genome-wide identification of Pfh1 binding sites, comprehensive analysis of the effects of Pfh1 depletion on replication and DNA damage, and proteomic analysis of Pfh1 interaction partners by immunoaffinity purification mass spectrometry. Of the 621 high confidence Pfh1-binding sites in wild type cells, about 40% were sites of fork slowing (as marked by high DNA polymerase occupancy) and/or DNA damage (as marked by high levels of phosphorylated H2A). The replication and integrity of tRNA and 5S rRNA genes, highly transcribed RNA polymerase II genes, and nucleosome depleted regions were particularly Pfh1-dependent. The association of Pfh1 with genomic integrity at highly transcribed genes was S phase dependent, and thus unlikely to be an artifact of high transcription rates. Although Pfh1 affected replication and suppressed DNA damage at discrete sites throughout the genome, Pfh1 and the replicative DNA polymerase bound to similar extents to both Pfh1-dependent and independent sites, suggesting that Pfh1 is proximal to the replication machinery during S phase. Consistent with this interpretation, Pfh1 co-purified with many key replisome components, including the hexameric MCM helicase, replicative DNA polymerases, RPA, and the processivity clamp PCNA in an S phase dependent manner. Thus, we conclude that Pfh1 is an accessory DNA helicase that interacts with the replisome and promotes replication and suppresses DNA damage at hard-to-replicate sites. These data provide insight into mechanisms by which this evolutionarily conserved helicase helps preserve genome integrity.

  • 48. McDonald, Karin R
    et al.
    Sabouri, Nasim
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Webb, Christopher J
    Zakian, Virginia A
    The Pif1 family helicase Pfh1 facilitates telomere replication and has an RPA-dependent role during telomere lengthening2014In: DNA Repair, ISSN 1568-7864, E-ISSN 1568-7856, Vol. 24, p. 80-86Article in journal (Refereed)
    Abstract [en]

    Pif1 family helicases are evolutionary conserved 5'-3' DNA helicases. Pfh1, the sole Schizosaccharomyces pombe Pif1 family DNA helicase, is essential for maintenance of both nuclear and mitochondrial DNAs. Here we show that its nuclear functions include roles in telomere replication and telomerase action. Pfh1 promoted semi-conservative replication through telomeric DNA, as replication forks moved more slowly through telomeres when Pfh1 levels were reduced. Unlike other organisms, S. pombe cells overexpressing Pfh1 displayed markedly longer telomeres. Because this lengthening occurred in the absence of homologous recombination but not in a replication protein A mutant (rad11-D223Y) that has defects in telomerase function, it is probably telomerase-mediated. The effects of Pfh1 on telomere replication and telomere length are likely direct as Pfh1 exhibited high telomere binding in cells expressing endogenous levels of Pfh1. These findings argue that Pfh1 is a positive regulator of telomere length and telomere replication.

  • 49. Miralles Fusté, Javier
    et al.
    Shi, Yonghong
    Wanrooij, Sjoerd
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Zhu, Xuefeng
    Jemt, Elisabeth
    Persson, Orjan
    Sabouri, Nasim
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Gustafsson, Claes M
    Falkenberg, Maria
    In vivo occupancy of mitochondrial single-stranded DNA binding protein supports the strand displacement mode of DNA replication2014In: PLOS Genetics, ISSN 1553-7390, E-ISSN 1553-7404, Vol. 10, no 12, p. e1004832-Article in journal (Refereed)
    Abstract [en]

    Mitochondrial DNA (mtDNA) encodes for proteins required for oxidative phosphorylation, and mutations affecting the genome have been linked to a number of diseases as well as the natural ageing process in mammals. Human mtDNA is replicated by a molecular machinery that is distinct from the nuclear replisome, but there is still no consensus on the exact mode of mtDNA replication. We here demonstrate that the mitochondrial single-stranded DNA binding protein (mtSSB) directs origin specific initiation of mtDNA replication. MtSSB covers the parental heavy strand, which is displaced during mtDNA replication. MtSSB blocks primer synthesis on the displaced strand and restricts initiation of light-strand mtDNA synthesis to the specific origin of light-strand DNA synthesis (OriL). The in vivo occupancy profile of mtSSB displays a distinct pattern, with the highest levels of mtSSB close to the mitochondrial control region and with a gradual decline towards OriL. The pattern correlates with the replication products expected for the strand displacement mode of mtDNA synthesis, lending strong in vivo support for this debated model for mitochondrial DNA replication.

  • 50.
    Mörén, Lina
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Metabolomics and proteomics studies of brain tumors: a chemometric bioinformatics approach2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The WHO classification of brain tumors is based on histological features and the aggressiveness of the tumor is classified from grade I to IV, where grade IV is the most aggressive. Today, the correlation between prognosis and tumor grade is the most important component in tumor classification. High grade gliomas, glioblastomas, are associated with poor prognosis and a median survival of 14 months including all available treatments. Low grade meningiomas, usually benign grade I tumors, are in most cases cured by surgical resection. However despite their benign appearance grade I meningiomas can, without any histopathological signs, in some cases develop bone invasive growth and become lethal. Thus, it is necessary to improve conventional treatment modalities, develop new treatment strategies and improve the knowledge regarding the basic pathophysiology in the classification and treatment of brain tumors.

    In this thesis, both proteomics and metabolomics have been applied in the search for biomarkers or biomarker patterns in two different types of brain tumors, gliomas and meningiomas. Proteomic studies were carried out mainly by surface enhanced laser desorption ionization time of flight mass spectrometry (SELDI-TOF-MS). In one of the studies, isobaric tags for relative and absolute quantitation (iTRAQ) labeling in combination with high-performance liquid chromatography (HPLC) was used for protein detection and identification. For metabolomics, gas-chromatography time-of-flight mass spectrometry (GC-TOF-MS) has been the main platform used throughout this work for generation of robust global metabolite profiles in tissue, blood and cell cultures. To deal with the complexity of the generated data, and to be able to extract relevant biomarker patters or latent biomarkers, for interpretation, prediction and prognosis, bioinformatic strategies based on chemometrics were applied throughout the studies of the thesis.

    In summary, we detected differentiating protein profiles between invasive and non-invasive meningiomas, in both fibrous and meningothelial tumors. Furthermore, in a different study we discovered treatment induce protein pattern changes in a rat glioma model treated with an angiogenesis inhibitor. We identified a cluster of proteins linked to angiogenesis. One of those proteins, HSP90, was found elevated in relation to treatment in tumors, following ELISA validation. An interesting observation in a separate study was that it was possible to detect metabolite pattern changes in the serum metabolome, as an effect of treatment with radiotherapy, and that these pattern changes differed between different patients, highlighting a possibility for monitoring individual treatment response.  In the fourth study of this work, we investigated tissue and serum from glioma patients that revealed differences in the metabolome between glioblastoma and oligodendroglioma, as well as between oligodendroglioma grade II and grade III. In addition, we discovered metabolite patterns associated to survival in both glioblastoma and oligodendroglioma. In our final work, we identified metabolite pattern differences between cell lines from a subgroup of glioblastomas lacking argininosuccinate synthetase (ASS1) expression, (ASS1 negative glioblastomas), making them auxotrophic for arginine, a metabolite required for tumor growth and proliferation, as compared to glioblastomas with normal ASS1 expression (ASS1 positive). From the identified metabolite pattern differences we could verify the hypothesized alterations in the arginine biosynthetic pathway. We also identified additional interesting metabolites that may provide clues for future diagnostics and treatments. Finally, we were able to verify the specific treatment effect of ASS1 negative cells by means of arginine deprivation on a metabolic level.

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