umu.sePublications
Change search
Refine search result
2345678 201 - 250 of 419
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 201.
    Kumar, Keshav
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Cava, Felipe
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Constraint randomised non-negative factor analysis (CRNNFA): an alternate chemometrics approach for analysing the biochemical data sets2017In: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 142, no 11, p. 1916-1928Article in journal (Refereed)
    Abstract [en]

    The present work introduces an alternate chemometrics approach constraint randomised non-negative factor analysis (CRNNFA) for analysing the bioanalytical data sets. The CRNNFA algorithm provides the outputs that are easy to interpret and correlate with the real chromatograms. The CRNNFA algorithm achieves termination when the iteration limit is reached circumventing the premature convergence. Theoretical and computational aspects of the proposed method are also described. The analytical and computational potential of CRNNFA are successfully tested by analysing the complex chromatograms of the peptidoglycan samples belonging to the Alphaproteobacterium members. The obtained results clearly show that CRNNFA can easily trace the compositional variability of the peptidoglycan samples. In summary, the proposed method in general can be a potential alternate approach for analysing the data sets obtained from different analytical and clinical fields.

  • 202.
    Kumlin, Alfa
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    The metal-binding site of Pol2 is necessary for polymerisation activity Experimental studies on a unique structure in the catalytic subunit of DNA polymerase ε2017Independent thesis Basic level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 203. Kuzmenko, Anton
    et al.
    Derbikova, Ksenia
    Hauryliuk, Vasili
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Insitute of Technology, Tartu University, Tartu, Estonia.
    Kamenski, Piotr
    Aim23 is an yeast mitochondrial translation initiation factor 3 which is unnecessary for protein synthesis2015In: Yeast, ISSN 0749-503X, E-ISSN 1097-0061, Vol. 32, no Suppl. 1, p. S192-S193Article in journal (Other academic)
    Abstract [en]

    Mitochondria are essential organelles of virtually all eukaryotic cells. They have their own genome and are able to transcribe and translate their genetic material. The system of mitochondrial protein synthesis is organized in a manner close to that of prokaryotes. However, mitochondrial DNA contains just a few protein-coded genes (9 in yeast, 13 in humans), so the mitochondrial translation system deals with a limited number of mRNAs. The mitochondrial translation machinery is also somewhat lineage-specific, with various components being gained and lost in different taxonomic groups. The classical bacterial initiation factors (IFs) IF1, IF2 and IF3 are universal in prokaryotes, but only IF2 is universal in mitochondria (mIF2). No IF1 has been identified in mitochondria of any organism. An insertion in mIF2 has been suggested to functionally compensate for the absence of mIF1. Mitochondrial IF3 (mIF3), although known to be present in various eukaryotes, has not been identified for many years in budding yeast Saccharomyces cerevisiae, the model organism for studying mitochondrial translation in vivo. In 2012, we have proven that IF3 does present in yeast mitochondria, and it is Aim23 protein. In the present study, we have characterized the effects of AIM23 gene deletion on yeast mitochondrial function. One could suggest that such a deletion would lead to a complete loss of respiration, translation and other molecular processes in mitochondria. However, this was not the case: the growth of AIM23∆ yeast on clycerol-containing media was suppressed in first 1-2 days only and reached the levels of wild-type in 3-4 days. AIM23∆ cells also were able to respire. Interestingly, we observed a very unusual pattern of mitochondrially-synthesized proteins in the ΔAIM23 strain. The amount of several proteins is decreased in the mutants compared to the wild-type but the amount of some others is increased. We conclude that the yeast cells are able to adapt somehow to the absence of Aim23p.

  • 204.
    Köhn, Linda
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Johansson, Mikael
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Grankvist, Kjell
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Clinical chemistry.
    Nilsson, Jonas
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Liquid biopsies in lung cancer: time to implement research technologies in routine care?2017In: Annals of Translational Medicine, ISSN 2305-5839, E-ISSN 2305-5847, Vol. 5, no 13, article id 278Article, review/survey (Refereed)
    Abstract [en]

    Lung cancer is the leading cause of cancer mortality. A substantial progress in the understanding of lung cancer biology has resulted in several promising targeted therapies for advanced disease. Druggable targets today include point mutations such as EGFR, BRAF and re-arrangements in genes such as ALK and ROS1. Liquid biopsies collecting e.g., circulating tumor DNA (ctDNA) reflects overall tumor information and is not biased by analyzing of only a small fraction of the tumor and is always accessible in contrast to the lung cancer tissue. Technological advances in detection of low frequency mutation variants in ctDNA have made it the dominating liquid biopsy platform in terms of utility and sensitivity. Circulating DNA or RNA may possible be used to define populations with higher risk of developing lung cancer, thus reducing screening cohorts and increasing the positive predictive value of screening. Blood based-tests may also aid to identify genetic alterations several weeks prior to radiologically verified recurrence and may be of great value in the follow-up of lung cancer patients. Besides being an alternative to invasive biopsies in selected cases, liquid biopsies offer a unique possibility to monitor treatment response following medical treatment as well as treatment response and resistance development after targeted therapy, giving a possibility to modify the treatment after the genetic profile of the tumor. Ideally, genetic alterations found in ctDNA could be tracked in real-time discriminating between fast-growing life-threatening tumors from more indolent slow growing tumors or premalignant growth that are of no concern for the wellbeing of the patient. This review focuses on future perspectives of liquid biopsies in lung cancer care for different clinical settings and present current technological platforms for further discussion of possible strategies for implementation of liquid biopsies in lung cancer.

  • 205.
    Lagerkvist, Birgitta Json
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lundström, Nils-Göran
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lead- and cadmium levels in children living close to a copper and lead smelter in Sweden2004In: Biometals, ISSN 0966-0844, E-ISSN 1572-8773, Vol. 17, no 5, p. 593-594Article in journal (Other academic)
  • 206. Laitman, Yael
    et al.
    Feng, Bing-Jian
    Zamir, Itay M
    The Susanne Levy Gertner Oncogenetics Unit, The Danek Gertner Institute of Human Genetics, Chaim Sheba Medical Center, Tel-Hashomer, Israel.
    Weitzel, Jeffrey N
    Duncan, Paul
    Port, Danielle
    Thirthagiri, Eswary
    Teo, Soo-Hwang
    Evans, Gareth
    Latif, Ayse
    Newman, William G
    Gershoni-Baruch, Ruth
    Zidan, Jamal
    Shimon-Paluch, Shani
    Goldgar, David
    Friedman, Eitan
    Haplotype analysis of the 185delAG BRCA1 mutation in ethnically diverse populations2013In: European Journal of Human Genetics, ISSN 1018-4813, E-ISSN 1476-5438, Vol. 21, no 2, p. 212-216Article in journal (Refereed)
    Abstract [en]

    The 185delAG* BRCA1 mutation is encountered primarily in Jewish Ashkenazi and Iraqi individuals, and sporadically in non-Jews. Previous studies estimated that this is a founder mutation in Jewish mutation carriers that arose before the dispersion of Jews in the Diaspora ~2500 years ago. The aim of this study was to assess the haplotype in ethnically diverse 185delAG* BRCA1 mutation carriers, and to estimate the age at which the mutation arose. Ethnically diverse Jewish and non-Jewish 185delAG*BRCA1 mutation carriers and their relatives were genotyped using 15 microsatellite markers and three SNPs spanning 12.5 MB, encompassing the BRCA1 gene locus. Estimation of mutation age was based on a subset of 11 markers spanning a region of ~5 MB, using a previously developed algorithm applying the maximum likelihood method. Overall, 188 participants (154 carriers and 34 noncarriers) from 115 families were included: Ashkenazi, Iraq, Kuchin-Indians, Syria, Turkey, Iran, Tunisia, Bulgaria, non-Jewish English, non-Jewish Malaysian, and Hispanics. Haplotype analysis indicated that the 185delAG mutation arose 750-1500 years ago. In Ashkenazim, it is a founder mutation that arose 61 generations ago, and with a small group of founder mutations was introduced into the Hispanic population (conversos) ~650 years ago, and into the Iraqi-Jewish community ~450 years ago. The 185delAG mutation in the non-Jewish populations in Malaysia and the UK arose at least twice independently. We conclude that the 185delAG* BRCA1 mutation resides on a common haplotype among Ashkenazi Jews, and arose about 61 generations ago and arose independently at least twice in non-Jews.

  • 207. Lampe, Elisabeth O.
    et al.
    Brenz, Yannick
    Herrmann, Lydia
    Repnik, Urska
    Griffiths, Gareth
    Zingmark, Carl
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Sjöstedt, Anders
    Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS). Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Winther-Larsen, Hanne C.
    Hagedorn, Monica
    Dissection of Francisella-Host Cell Interactions in Dictyostelium discoideum2016In: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 82, no 5, p. 1586-1598Article in journal (Refereed)
    Abstract [en]

    Francisella bacteria cause severe disease in both vertebrates and invertebrates and include one of the most infectious human pathogens. Mammalian cell lines have mainly been used to study the mechanisms by which Francisella manipulates its host to replicate within a large variety of hosts and cell types, including macrophages. Here, we describe the establishment of a genetically and biochemically tractable infection model: the amoeba Dictyostelium discoideum combined with the fish pathogen Francisella noatunensis subsp. noatunensis. Phagocytosed F. noatunensis subsp. noatunensis interacts with the endosomal pathway and escapes further phagosomal maturation by translocating into the host cell cytosol. F. noatunensis subsp. noatunensis lacking IglC, a known virulence determinant required for Francisella intracellular replication, follows the normal phagosomal maturation and does not grow in Dictyostelium. The attenuation of the F. noatunensis subsp. noatunensis Delta iglC mutant was confirmed in a zebrafish embryo model, where growth of F. noatunensis subsp. noatunensis Delta iglC was restricted. In Dictyostelium, F. noatunensis subsp. noatunensis interacts with the autophagic machinery. The intracellular bacteria colocalize with autophagic markers, and when autophagy is impaired (Dictyostelium Delta atg1), F. noatunensis subsp. noatunensis accumulates within Dictyostelium cells. Altogether, the Dictyostelium-F. noatunensis subsp. noatunensis infection model recapitulates the course of infection described in other host systems. The genetic and biochemical tractability of the system allows new approaches to elucidate the dynamic interactions between pathogenic Francisella and its host organism.

  • 208.
    Larsson, Göran
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Saarikettu, Juha
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Sveshnikova, Natalia
    Zdunek, Janusz
    Schleucher, Jürgen
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Grundström, Thomas
    Wijmenga, Sybren
    A third principle of protein:protein recognition: the calmodulin dimer interaction with basic-helix-loop-helix transcription factorsManuscript (Other academic)
  • 209.
    Larsson, Miriam
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Uvell, Hanna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Sandström, Jenny
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Rydén, Patrik
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Selth, Luke A.
    Mechanisms of Transcription Laboratory, Clare Hall Laboratories, Cancer Research UK London Research Institute.
    Björklund, Stefan
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Functional Studies of the Yeast Med5, Med15 and Med16 Mediator Tail Subunits2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 8, p. e73137-Article in journal (Refereed)
    Abstract [en]

    The yeast Mediator complex can be divided into three modules, designated Head, Middle and Tail. Tail comprises the Med2, Med3, Med5, Med15 and Med16 protein subunits, which are all encoded by genes that are individually non-essential for viability. In cells lacking Med16, Tail is displaced from Head and Middle. However, inactivation of MED5/MED15 and MED15/MED16 are synthetically lethal, indicating that Tail performs essential functions as a separate complex even when it is not bound to Middle and Head. We have used the N-Degron method to create temperature-sensitive (ts) mutants in the Mediator tail subunits Med5, Med15 and Med16 to study the immediate effects on global gene expression when each subunit is individually inactivated, and when Med5/15 or Med15/16 are inactivated together. We identify 25 genes in each double mutant that show a significant change in expression when compared to the corresponding single mutants and to the wild type strain. Importantly, 13 of the 25 identified genes are common for both double mutants. We also find that all strains in which MED15 is inactivated show down-regulation of genes that have been identified as targets for the Ace2 transcriptional activator protein, which is important for progression through the G1 phase of the cell cycle. Supporting this observation, we demonstrate that loss of Med15 leads to a G1 arrest phenotype. Collectively, these findings provide insight into the function of the Mediator Tail module.

  • 210. Lasswitz, Lisa
    et al.
    Chandra, Naresh
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Arnberg, Niklas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Gerold, Gisa
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology. Umeå University, Faculty of Medicine, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM). Institute for Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Medical School Hannover and the Helmholtz Centre for Infection Research, Hannover, Germany.
    Glycomics and Proteomics Approaches to Investigate Early Adenovirus-Host Cell Interactions2018In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 430, no 13, p. 1863-1882Article in journal (Refereed)
    Abstract [en]

    Adenoviruses as most viruses rely on glycan and protein interactions to attach to and enter susceptible host cells. The Adenoviridae family comprises more than 80 human types and they differ in their attachment factor and receptor usage, which likely contributes to the diverse tropism of the different types. In the past years, methods to systematically identify glycan and protein interactions have advanced. In particular sensitivity, speed and coverage of mass spectrometric analyses allow for high-throughput identification of glycans and peptides separated by liquid chromatography. Also, developments in glycan microarray technologies have led to targeted, high-throughput screening and identification of glycan-based receptors. The mapping of cell surface interactions of the diverse adenovirus types has implications for cell, tissue, and species tropism as well as drug development. Here we review known adenovirus interactions with glycan- and protein-based receptors, as well as glycomics and proteomics strategies to identify yet elusive virus receptors and attachment factors. We finally discuss challenges, bottlenecks, and future research directions in the field of non-enveloped virus entry into host cells.

  • 211.
    Lauvrud, Anne Therese
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Kelk, Peyman
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Wiberg, Mikael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Kingham, Paul J.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Characterization of human adipose tissue-derived stem cells with enhanced angiogenic and adipogenic properties2017In: Journal of Tissue Engineering and Regenerative Medicine, ISSN 1932-6254, E-ISSN 1932-7005, Vol. 11, no 9, p. 2490-2502Article in journal (Refereed)
    Abstract [en]

    Autologous fat grafting is a popular method for soft tissue reconstructions but graft survival remains highly unpredictable. Supplementation of the graft with the stromal vascular fraction (SVF) or cultured adipose tissue-derived stem cells (ASCs) can enhance graft viability. In this study we have examined the phenotypic properties of a selected population of cells isolated from ASCs, with a view to determining their suitability for transplantation into grafts. ASCs were isolated from the SVF of human abdominal fat (n = 8 female patients) and CD146(+) cells were selected using immunomagnetic beads. The angiogenic and adipogenic properties of the positively selected cells were compared with the negative fraction. CD146(+) cells expressed the immunophenotypic characteristics of pericytes. With prolonged in vitro expansion, CD146(-) cells exhibited increased population doubling times and morphological signs of senescence, whereas CD146(+) cells did not. CD146(+) cells expressed higher levels of the angiogenic molecules VEGF-A, angiopoietin-1 and FGF-1. Conditioned medium taken from CD146(+) cells significantly increased formation of in vitro endothelial cell tube networks, whereas CD146(-) cells did not. CD146(+) cells could be differentiated into adipocytes in greater numbers than CD146(-) cells. Consistent with this, differentiated CD146(+) cells expressed higher levels of the adipocyte markers adiponectin and leptin. These results suggest that CD146(+) cells selected from a heterogeneous mix of ASCs have more favourable angiogenic and adipogenic properties, which might provide significant benefits for reconstructive and tissue-engineering applications. Copyright © 2016 John Wiley & Sons, Ltd.

  • 212. Lemor, Mélanie
    et al.
    Kong, Ziqing
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Henry, Etienne
    Brizard, Raphaël
    Laurent, Sébastien
    Bossé, Audrey
    Henneke, Ghislaine
    Differential Activities of DNA Polymerases in Processing Ribonucleotides during DNA Synthesis in Archaea2018In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 430, no 24, p. 4908-4924Article in journal (Refereed)
    Abstract [en]

    Consistent with the fact that ribonucleotides (rNTPs) are in excess over deoxyribonucleotides (dNTPs) in vivo, recent findings indicate that replicative DNA polymerases (DNA Pols) are able to insert ribonucleotides (rNMPs) during DNA synthesis, raising crucial questions about the fidelity of DNA replication in both Bacteria and Eukarya. Here, we report that the level of rNTPs is 20-fold higher than that of dNTPs in Pyrococcus abyssi cells. Using dNTP and rNTP concentrations present in vivo, we recorded rNMP incorporation in a template specific manner during in vitro synthesis, with the family-D DNA Pol (PolD) having the highest propensity compared with the family-B DNA Pol and the p41/p46 complex. We also showed that ribonucleotides accumulate at a relatively high frequency in the genome of wild-type Thermococcales cells, and this frequency significantly increases upon deletion of RNase HII, the major enzyme responsible for the removal of RNA from DNA. Because ribonucleotides remain in genomic DNA, we then analyzed the effects on polymerization activities by the three DNA Pols. Depending on the identity of the base and the sequence context, all three DNA Pols bypass rNMP-containing DNA templates with variable efficiency and nucleotide (mis)incorporation ability. Unexpectedly, we found that PoID correctly base-paired a single ribonucleotide opposite rNMP-containing DNA templates. An evolutionary scenario is discussed concerning rNMP incorporation into DNA and genome stability.

  • 213. Licciardello, Marco P.
    et al.
    Ringler, Anna
    Markt, Patrick
    Klepsch, Freya
    Lardeau, Charles-Hugues
    Sdelci, Sara
    Schirghuber, Erika
    Mueller, Andre C.
    Caldera, Michael
    Wagner, Anja
    Herzog, Rebecca
    Penz, Thomas
    Schuster, Michael
    Boidol, Bernd
    Duernberger, Gerhard
    Folkvaljon, Yasin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Urology and Andrology.
    Stattin, Pär
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Urology and Andrology. Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
    Ivanov, Vladimir
    Colinge, Jacques
    Bock, Christoph
    Kratochwill, Klaus
    Menche, Joerg
    Bennett, Keiryn L.
    Kubicek, Stefan
    A combinatorial screen of the CLOUD uncovers a synergy targeting the androgen receptor2017In: Nature Chemical Biology, ISSN 1552-4450, E-ISSN 1552-4469, Vol. 13, no 7, p. 771-778Article in journal (Refereed)
    Abstract [en]

    Approved drugs are invaluable tools to study biochemical pathways, and further characterization of these compounds may lead to repurposing of single drugs or combinations. Here we describe a collection of 308 small molecules representing the diversity of structures and molecular targets of all FDA-approved chemical entities. The CeMM Library of Unique Drugs (CLOUD) covers prodrugs and active forms at pharmacologically relevant concentrations and is ideally suited for combinatorial studies. We screened pairwise combinations of CLOUD drugs for impairment of cancer cell viability and discovered a synergistic interaction between flutamide and phenprocoumon (PPC). The combination of these drugs modulates the stability of the androgen receptor (AR) and resensitizes AR-mutant prostate cancer cells to flutamide. Mechanistically, we show that the AR is a substrate for gamma-carboxylation, a post-translational modification inhibited by PPC. Collectively, our data suggest that PPC could be repurposed to tackle resistance to antiandrogens in prostate cancer patients.

  • 214. Lindahl, Anna
    et al.
    Saaf, Siv
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Lehtio, Janne
    Nordström, Anders
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Karolinska Inst, Sci Life Lab, Dept Oncol Pathol, Stockholm, Sweden.
    Tuning Metabolome Coverage in Reversed Phase LC-MS Metabolomics of MeOH Extracted Samples Using the Reconstitution Solvent Composition2017In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 89, no 14, p. 7356-7364Article in journal (Refereed)
    Abstract [en]

    Considering the physicochemical diversity of the metabolome, untargeted metabolomics will inevitably discriminate against certain compound classes. Efforts are nevertheless made to maximize the metabolome coverage. Contrary to the main steps of a typical liquid chromatography-mass spectrometry (LC-MS) metabolomics workflow, such as metabolite extraction, the sample reconstitution step has not been optimized for maximal metabolome coverage. This sample concentration step typically occurs after metabolite extraction, when dried samples are reconstituted in a solvent for injection on column. The aim of this study was to evaluate the impact of the sample reconstitution solvent composition on metabolome coverage in untargeted LCMS metabolomics. Lysogeny Broth medium samples reconstituted in MeOH/H2O ratios ranging from 0 to 100% MeOH and analyzed with untargeted reversed phase LC-MS showed that the highest number of metabolite features (n = 1500) was detected in samples reconstituted in 100% H2O. As compared to a commonly used reconstitution solvent mixture of 50/50 MeOH/H2O, our results indicate that the small fraction of compounds increasing in peak area response by the addition of MeOH to H2O, 5%, is outweighed by the fraction of compounds with decreased response, 57%. We evaluated our results on human serum samples from lymphoma patients and healthy control subjects. Reconstitution in 100% H2O resulted in a higher number of significant metabolites discriminating between these two groups than both 50% and 100% MeOH. These findings show that the sample reconstitution step has a clear impact on the metabolome coverage of MeOH extracted biological samples, highlighting the importance of the reconstitution solvent composition for untargeted discovery metabolomics.

  • 215.
    Lindhagen Persson, Malin
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Diez, I
    Vestling, M
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Cytotoxic properties of transthyretin as a function of thermodynamic and kinetic stabilityManuscript (preprint) (Other academic)
  • 216.
    Lindhagen-Persson, Malin
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Brännström, Kristoffer
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Vestling, Monika
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Steinitz, Michael
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Amyloid-β oligomer specificity mediated by the IgM isotype: implications for a specific protective mechanism exerted by endogenous auto-antibodies2010In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 5, no 11, p. e13928-Article in journal (Refereed)
    Abstract [en]

    Background Alzheimers disease (AD) has been strongly linked to an anomalous self-assembly of the amyloid-β peptide (Aβ). The correlation between clinical symptoms of AD and Aβ depositions is, however, weak. Instead small and soluble Aβ oligomers are suggested to exert the major pathological effects. In strong support of this notion, immunological targeting of Aβ oligomers in AD mice-models shows that memory impairments can be restored without affecting the total burden of Aβ deposits. Consequently a specific immunological targeting of Aβ oligomers is of high therapeutic interest.

    Methodology/Principal Findings Previously the generation of conformational-dependent oligomer specific anti-Aβ antibodies has been described. However, to avoid the difficult task of identifying a molecular architecture only present on oligomers, we have focused on a more general approach based on the hypothesis that all oligomers expose multiple identical epitopes and therefore would have an increased binding to a multivalent receptor. Using the polyvalent IgM immunoglobulin we have developed a monoclonal anti-Aβ antibody (OMAB). OMAB only demonstrates a weak interaction with Aβ monomers and dimers having fast on and off-rate kinetics. However, as an effect of avidity, its interaction with Aβ-oligomers results in a strong complex with an exceptionally slow off-rate. Through this mechanism a selectivity towards Aβ oligomers is acquired and OMAB fully inhibits the cytotoxic effect exerted by Aβ(1-42) at highly substoichiometric ratios. Anti-Aβ auto-antibodies of IgM isotype are frequently present in the sera of humans. Through a screen of endogenous anti-Aβ IgM auto-antibodies from a group of healthy individuals we show that all displays a preference for oligomeric Aβ.

    Conclusions/Significance Taken together we provide a simple and general mechanism for targeting of oligomers without the requirement of conformational-dependent epitopes. In addition, our results suggest that IgM anti-Aβ auto-antibodies may exert a more specific protective mechanism in vivo than previously anticipated.

  • 217.
    Lindhagen-Persson, Malin
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Vestling, M
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Reixach, N
    Division of Rheumatology Research, W.M. Keck Autoimmune Disease Center, The Scripps Research Institute, La Jolla, CA, USA.
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Formation of cytotoxic transthyretin is not dependent on inter-molecular disulphide bridges commonly found within the amyloid form2008In: Amyloid: Journal of Protein Folding Disorders, ISSN 1350-6129, E-ISSN 1744-2818, Vol. 15, no 4, p. 240-245Article in journal (Refereed)
    Abstract [en]

    Familial amyloidotic polyneuropathy (FAP) is linked to destabilising point mutations in the human plasma protein transthyretin (TTR). Consistent with similar amyloid disorders, low molecular weight TTR oligomers have been shown to exert the major cytotoxic effect. The amyloid structure of TTR contains non-native inter-molecular disulphide linkages via the cysteine at position 10 (Cys10). Moreover, substitution of Cys10 in a mouse model for TTR-amyloidosis abolishes TTR deposits, indicating an important role of Cys10 in FAP pathogenesis. However, the role of disulphide bridges in TTR cytotoxicity has not been elucidated. By probing Cys10Ser TTR variants to the human neuroblastoma SH-SY5Y cell line, we have addressed this question, and our results clearly show that formation of an inter-molecular disulphide bridge is not a pre-requisite for TTR cytotoxicity. This finding suggests that prevention of inter-molecular TTR disulphide bridges as a therapeutic intervention will not impair the cytotoxic potential of TTR.

  • 218.
    Liu, Huan
    et al.
    School of Public Health, Health Science Center, Xi'an Jiaotong University, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission of PR China, Xi'an, China.
    Yang, Lei
    School of Public Health, Health Science Center, Xi'an Jiaotong University, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission of PR China, Xi'an, China.
    Yu, Fang Fang
    School of Public Health, Health Science Center, Xi'an Jiaotong University, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission of PR China, Xi'an, China.
    Wang, Sen
    School of Public Health, Health Science Center, Xi'an Jiaotong University, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission of PR China, Xi'an, China.
    Wu, Cuiyan
    School of Public Health, Health Science Center, Xi'an Jiaotong University, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission of PR China, Xi'an, China.
    Qu, Chengjuan
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Lammi, Mikko
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). School of Public Health, Health Science Center, Xi'an Jiaotong University, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission of PR China, Xi'an, China.
    Guo, Xiong
    School of Public Health, Health Science Center, Xi'an Jiaotong University, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission of PR China, Xi'an, China.
    The potential of induced pluripotent stem cells as a tool to study skeletal dysplasias and cartilage-related pathologic conditions2017In: Osteoarthritis and Cartilage, ISSN 1063-4584, E-ISSN 1522-9653, Vol. 25, no 5, p. 616-624, article id 27919783Article, review/survey (Refereed)
    Abstract [en]

    The development of induced pluripotent stem cells (iPSCs) technology has opened up new horizons for development of new research tools especially for skeletal dysplasias, which often lack human disease models. Regenerative medicine and tissue engineering could be the next areas to benefit from refinement of iPSC methods to repair focal cartilage defects, while applications for osteoarthritis (OA) and drug screening have evolved rather slowly. Although the advances in iPSC research of skeletal dysplasias and repair of focal cartilage lesions are not directly relevant to OA, they can be considered to pave the way to future prospects and solutions to OA research, too. The same problems which face the present cell-based treatments of cartilage injuries concern also the iPSC-based ones. However, established iPSC lines, which have no genomic aberrations and which efficiently differentiate into extracellular matrix secreting chondrocytes, could be an invaluable cell source for cell transplantations in the future. The safety issues concerning the recipient risks of teratoma formation and immune response still have to be solved before the potential use of iPSCs in cartilage repair of focal cartilage defects and OA.

  • 219.
    Liu, Huan
    et al.
    School of Public Health, Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission of People's Republic of China, Xi'an Jiaotong University, Xi'an, China..
    Yu, Fangfang
    School of Public Health, Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission of People's Republic of China, Xi'an Jiaotong University, Xi'an, China..
    Shao, Wanzhen
    School of Public Health, Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission of People's Republic of China, Xi'an Jiaotong University, Xi'an, China..
    Ding, Dexiu
    School of Public Health, Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission of People's Republic of China, Xi'an Jiaotong University, Xi'an, China..
    Yu, Zhidao
    School of Public Health, Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission of People's Republic of China, Xi'an Jiaotong University, Xi'an, China..
    Chen, Fengshi
    School of Public Health, Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission of People's Republic of China, Xi'an Jiaotong University, Xi'an, China..
    Geng, Dong
    School of Public Health, Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission of People's Republic of China, Xi'an Jiaotong University, Xi'an, China..
    Tan, Xiwang
    School of Public Health, Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission of People's Republic of China, Xi'an Jiaotong University, Xi'an, China..
    Lammi, Mikko J
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). School of Public Health, Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission of People's Republic of China, Xi'an Jiaotong University, Xi'an, China..
    Guo, Xiong
    School of Public Health, Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission of People's Republic of China, Xi'an Jiaotong University, Xi'an, China..
    Associations between selenium content in hair and Kashin-Beck Disease/Keshan Disease in children in Northwestern China: a prospective cohort study2018In: Biological Trace Element Research, ISSN 0163-4984, E-ISSN 1559-0720, Vol. 184, no 1, p. 16-23, article id 28983831Article in journal (Refereed)
    Abstract [en]

    The objective of this study was to investigate the relationship between selenium content in hair and the incidence of Kashin-Beck disease (KBD) and Keshan disease (KD) in China. A prospective cohort study was conducted among children aged 5-12 years with different levels of low-selenium (group 1, Se ≤ 110 ng/g; group 2, 110 < Se ≤ 150 ng/g; and group 3, 150 < Se ≤ 200 ng/g) or selenium-supplemented (group 4, Se > 200 ng/g) exposure. A person-years approach was used to calculate the incidence and rate of positive clinical signs. Relative risk (RR), attributable risk, and etiologic fraction were used to determine the strength of association between selenium and disease incidence. Seven new KBD cases were diagnosed during 3-year follow-up. Positive clinical signs of KBD were found in 17.78 (95% confidence interval [CI] 14.27-21.29) cases per 100 person-years in group 1, 13.28 (9.82-16.74) in group 2, 12.95 (9.34-16.56) in group 3, and 8.18 (5.50-10.85) in group 4. Compared with group 4, the RR (95% CI) of groups 1, 2, and 3 were 2.17 (1.48-3.19), 1.62 (1.07-2.47), and 1.58 (1.03-2.43), respectively. Positive clinical signs of KD were 25.90 (18.62-33.18) cases per 100 person-years in group 1, 5.66 (1.26-10.06) in group 2, 4.60 (0.20-9.00) in group 3, and 14.62 (8.54-20.69) in group 4. Compared with group 4, the RR (95% CI) were 1.77 (1.07-2.93), 0.39 (0.16-0.93), and 0.31 (0.11-0.89), respectively. In children, the onset of KBD was negatively correlated with selenium content within a certain range. However, there may be a U-shaped association between selenium content and KD in children.

  • 220. Lokk, Kaie
    et al.
    Modhukur, Vijayachitra
    Rajashekar, Balaji
    Märtens, Kaspar
    Mägi, Reedik
    Kolde, Raivo
    Koltšina, Marina
    Nilsson, Torbjörn K
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Clinical chemistry.
    Vilo, Jaak
    Salumets, Andres
    Tõnisson, Neeme
    DNA methylome profiling of human tissues identifies global and tissue-specific methylation patterns2014In: Genome Biology, ISSN 1465-6906, E-ISSN 1474-760X, Vol. 15, no 4, p. r54-Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: DNA epigenetic modifications, such as methylation, are important regulators of tissue differentiation, contributing to processes of both development and cancer. Profiling the tissue-specific DNA methylome patterns will provide novel insights into normal and pathogenic mechanisms, as well as help in future epigenetic therapies. In this study, 17 somatic tissues from four autopsied humans were subjected to functional genome analysis using the Illumina Infinium HumanMethylation450 BeadChip, covering 486 428 CpG sites. RESULTS: Only 2% of the CpGs analyzed are hypermethylated in all 17 tissue specimens; these permanently methylated CpG sites are located predominantly in gene-body regions. In contrast, 15% of the CpGs are hypomethylated in all specimens and are primarily located in regions proximal to transcription start sites. A vast number of tissue-specific differentially methylated regions are identified and considered likely mediators of tissue-specific gene regulatory mechanisms since the hypomethylated regions are closely related to known functions of the corresponding tissue. Finally, a clear inverse correlation is observed between promoter methylation within CpG islands and gene expression data obtained from publicly available databases. CONCLUSIONS: This genome-wide methylation profiling study identified tissue-specific differentially methylated regions in 17 human somatic tissues. Many of the genes corresponding to these differentially methylated regions contribute to tissue-specific functions. Future studies may use these data as a reference to identify markers of perturbed differentiation and disease-related pathogenic mechanisms.

  • 221. Lundgren, Erik
    Amino acid naphthylamidase isozymes in human cells grown in vitro: Hormonal regulation and isozyme differentiation in cancer cells and normal cells1972Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The elucidation of regulatory mechanisms in higher organisms represents a front line problem in biochemical genetics. In Man the only material available for experimental studies of regulatory mechanisms is cells cultured in vitro. Enzymes which are differentiated into isozymes may have a complexgenetic background involving the action of more than one gene locus. The study of isozyme systems in cultured cells has developed into a valuable tool of increasing importance for the understanding of the genetic regulatorymechanisms in normal cells as well as in cancer cells.

    The purposes of this investigation were:

    1. to elucidate the isozyme differentiation of amino acid naphthylamidasein cultured human cancer cells and normal cells.

    2. to study the regulatory effects of steroid hormones especially hydrocortisoneon the levels of the different isozymes.

  • 222.
    Långsjö, Teemu
    et al.
    Department of Anatomy, Institute of Biomedicine, University of Kuopio, Kuopio, Finland; Department of Radiology, Vaasa Central Hospital, Vaasa, Finland.
    Vasara, Anna
    Department of Orthopaedics and Traumatology, Helsinki University Hospital, Helsinki, Finland.
    Hyttinen, Mika
    Department of Anatomy, Institute of Biomedicine, University of Kuopio, Kuopio, Finland.
    Lammi, Mikko
    Department of Biosciences, Applied Biotechnology, University of Kuopio, Kuopio, Finland.
    Kaukinen, Antti
    Department of Anatomy, Institute of Biomedicine, University of Kuopio, Kuopio, Finland.
    Helminen, Heikki
    Department of Anatomy, Institute of Biomedicine, University of Kuopio, Kuopio,.
    Kiviranta, Ilkka
    Department of Orthopaedics and Traumatology, Helsinki University Hospital, Helsinki, Finland; Department of Orthopaedics and Traumatology, Jyväskylä Central Hospital, Jyväskylä, Finland.
    Quantitative analysis of collagen network structure and fibril dimensions in cartilage repair with autologous chondrocyte transplantation.2010In: Cells Tissues Organs, ISSN 1422-6405, E-ISSN 1422-6421, Vol. 192, no 6, p. 351-360, article id 20664251Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: The aim of this study was to undertake a stereological analysis to quantify the dimensions of the collagen network in the repair tissue of porcine joints after they had been subjected to autologous chondrocyte transplantation (ACT).

    METHOD: ACT was used to repair cartilage lesions in knee joints of pigs. Electron-microscopic stereology, immunostaining for type II collagen, and quantitative polarized-light microscopy were utilized to study the collagen fibrils in the repair tissue 3 and 12 months after the operation.

    RESULTS: The collagen volume density (V(V)) was lower in the repair tissue than in normal cartilage at 3 months (20.4 vs. 23.7%) after the operation. The collagen surface density (S(V), 1.5·10(-2) vs. 3.1·10(-2) nm(2)/nm(3)) and V(V) increased with time in the repair tissue (20.4 vs. 44.7%). Quantitative polarized-light microscopy detected a higher degree of collagen parallelism in the repair tissue at 3 months after the operation (55.7 vs. 49.7%). In contrast, 1 year after the operation, fibril parallelism was lower in the repair tissue than in the control cartilage (47.5 vs. 69.8%).

    CONCLUSION: Following ACT, V(V) and S(V) increased in the repair tissue with time, reflecting maturation of the tissue. One year after the operation, there was a lower level of fibril organization in the repair tissue than in the control cartilage. Thus, the newly synthesized collagen fibrils in the repair tissue appeared to form a denser network than in the control cartilage, but the fibrils remained more randomly oriented.

  • 223. Macagno, Juan Pablo
    et al.
    Vera, Jesica Diaz
    Yu, Yachuan
    MacPherson, Iain
    Sandilands, Emma
    Palmer, Ruth
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Norman, Jim C.
    Frame, Margaret
    Vidal, Marcos
    FAK Acts as a Suppressor of RTK-MAP Kinase Signalling in Drosophila melanogaster Epithelia and Human Cancer Cells2014In: PLoS Genetics, ISSN 1553-7390, E-ISSN 1553-7404, Vol. 10, no 3, p. e1004262-Article in journal (Refereed)
    Abstract [en]

    Receptor Tyrosine Kinases (RTKs) and Focal Adhesion Kinase (FAK) regulate multiple signalling pathways, including mitogen-activated protein (MAP) kinase pathway. FAK interacts with several RTKs but little is known about how FAK regulates their downstream signalling. Here we investigated how FAK regulates signalling resulting from the overexpression of the RTKs RET and EGFR. FAK suppressed RTKs signalling in Drosophila melanogaster epithelia by impairing MAPK pathway. This regulation was also observed in MDA-MB-231 human breast cancer cells, suggesting it is a conserved phenomenon in humans. Mechanistically, FAK reduced receptor recycling into the plasma membrane, which resulted in lower MAPK activation. Conversely, increasing the membrane pool of the receptor increased MAPK pathway signalling. FAK is widely considered as a therapeutic target in cancer biology; however, it also has tumour suppressor properties in some contexts. Therefore, the FAK-mediated negative regulation of RTK/MAPK signalling described here may have potential implications in the designing of therapy strategies for RTK-driven tumours.

  • 224.
    Madhushani, Anjana
    et al.
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    del Peso-Santos, Teresa
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Moreno, Renata
    Rojo, Fernando
    Shingler, Victoria
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Transcriptional and translational control through the 5 '-leader region of the dmpR master regulatory gene of phenol metabolism2015In: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 17, no 1, p. 119-133Article in journal (Refereed)
    Abstract [en]

    Expression of pathways for dissimilation of toxic aromatic compounds such as (methyl)phenols interfaces both stress-response and carbon catabolite repression control cascades. In Pseudomonas putida, carbon catabolite repression is mediated by the protein Crc - a translational repressor that counteracts utilization of less-preferred carbon sources as growth substrates until they are needed. In this work we dissect the regulatory role of the 5-leader region (5-LR) of the dmpR gene that encodes the master regulator of (methyl)phenol catabolism. Using deletion and substitution mutants combined with artificial manipulations of Crc availability in P.putida, we present evidence that a DNA motif within the 5-leader region is critical for inhibition of the output from the Pr promoter that drives transcription of dmpR, while the RNA chaperone Hfq facilitates Crc-mediated translation repression through the 5-leader region of the dmpR mRNA. The results are discussed in the light of a model in which Hfq assists Crc to target a sequence within a loop formed by secondary structure of the 5-LR mRNA. Our results support the idea that Crc functions as a global translational inhibitor to co-ordinate hierarchical carbon utilization in Pseudomonads.

  • 225.
    Madsen, Rasmus Kirkegaard
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Rantapää-Dahlqvist, Solbritt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Reumatology.
    Lundstedt, Torbjörn
    AcureOmics AB, Tvistevägen 48, 907 36 Umeå, Sweden.
    Moritz, Thomas
    Umeå Plant Science Center, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-90183 Umeå, Sweden.
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Metabolic responses to change in disease activity during tumor necrosis factor inhibition in patients with rheumatoid arthritis2012In: Journal of Proteome Research, ISSN 1535-3893, E-ISSN 1535-3907, Vol. 11, no 7, p. 3796-3804Article in journal (Refereed)
    Abstract [en]

    Assessment of disease activity in patients with rheumatoid arthritis (RA) is of importance in the evaluation of treatment. The most important measure of disease activity is the Disease Activity Score counted in 28 joints (DAS28). In this study, we evaluated whether metabolic profiling could complement current measures of disease activity. Fifty-six patients, in two separate studies, were followed for two years after commencing anti-TNF therapy. DAS28 was assessed, and metabolic profiles were recorded at defined time points. Correlations between metabolic profile and DAS28 scores were analyzed using multivariate statistics. The metabolic responses to lowering DAS28 scores varied in different patients but could predict DAS28 scores at the individual and subgroup level models. The erythrocyte sedimentation rate (ESR) component in DAS28 was most correlated to the metabolite data, pointing to inflammation as the primary effect driving metabolic profile changes. Patients with RA had differing metabolic response to changes in DAS28 following anti-TNF therapy. This suggests that discovery of new metabolic biomarkers for disease activity will derive from studies at the individual and subgroup level. Increased inflammation, measured as ESR, was the main common effect seen in metabolic profiles from periods associated with high DAS28.

  • 226. Maguire, Casey A.
    et al.
    Balaj, Leonora
    Sivaraman, Sarada
    Crommentuijn, Matheus H. W.
    Ericsson, Maria
    Mincheva-Nilsson, Lucia
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Immunology.
    Baranov, Vladimir
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Immunology.
    Gianni, Davide
    Tannous, Bakhos A.
    Sena-Esteves, Miguel
    Breakefield, Xandra O.
    Skog, Johan
    Microvesicle-associated AAV Vector as a Novel Gene Delivery System2012In: Molecular Therapy, ISSN 1525-0016, E-ISSN 1525-0024, Vol. 20, no 5, p. 960-971Article in journal (Refereed)
    Abstract [en]

    Adeno-associated virus (AAV) vectors have shown remarkable efficiency for gene delivery to cultured cells and in animal models of human disease. However, limitations to AAV vectored gene transfer exist after intravenous transfer, including off-target gene delivery (e.g., liver) and low transduction of target tissue. Here, we show that during production, a fraction of AAV vectors are associated with microvesicles/exosomes, termed vexosomes (vector-exosomes). AAV capsids associated with the surface and in the interior of microvesicles were visualized using electron microscopy. In cultured cells, vexosomes outperformed conventionally purified AAV vectors in transduction efficiency. We found that purified vexosomes were more resistant to a neutralizing anti-AAV antibody compared to conventionally purified AAV. Finally, we show that vexosomes bound to magnetic beads can be attracted to a magnetized area in cultured cells. Vexosomes represent a unique entity which offers a promising strategy to improve gene delivery.

  • 227. Mahdavi, Jafar
    et al.
    Pirinccioglu, Necmettin
    Oldfield, Neil J.
    Carlsohn, Elisabet
    Stoof, Jeroen
    Aslam, Akhmed
    Self, Tim
    Cawthraw, Shaun A.
    Petrovska, Liljana
    Colborne, Natalie
    Sihlbom, Carina
    Borén, Thomas
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Wooldridge, Karl G.
    Ala'Aldeen, Dlawer A. A.
    A novel O-linked glycan modulates Campylobacter jejuni major outer membrane protein-mediated adhesion to human histo-blood group antigens and chicken colonization2014In: Open Biology, ISSN 2046-2441, E-ISSN 2046-2441, Vol. 4, no 1, p. 130202-Article in journal (Refereed)
    Abstract [en]

    Campylobacter jejuni is an important cause of human foodborne gastroenteritis; strategies to prevent infection are hampered by a poor understanding of the complex interactions between host and pathogen. Previous work showed that C. jejuni could bind human histo-blood group antigens (BgAgs) in vitro and that BgAgs could inhibit the binding of C. jejuni to human intestinal mucosa ex vivo. Here, the major flagella subunit protein (FlaA) and the major outer membrane protein (MOMP) were identified as BgAg-binding adhesins in C. jejuni NCTC11168. Significantly, the MOMP was shown to be O-glycosylated at Thr(268); previously only flagellin proteins were known to be O-glycosylated in C. jejuni. Substitution of MOMP Thr(268) led to significantly reduced binding to BgAgs. The O-glycan moiety was characterized as Gal(beta 1-3)-GalNAc(beta 1-4)-GalNAc(beta 1-4)-GalNAca1-Thr(268); modelling suggested that O-glycosylation has a notable effect on the conformation of MOMP and this modulates BgAg-binding capacity. Glycosylation of MOMP at Thr(268) promoted cell-to-cell binding, biofilm formation and adhesion to Caco-2 cells, and was required for the optimal colonization of chickens by C. jejuni, confirming the significance of this O-glycosylation in pathogenesis.

  • 228.
    Mahdavi, Jafar
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Microbiology.
    Sondén, B
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Microbiology.
    Hurtig, Marina
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Microbiology.
    Olfat, Farzad O
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Microbiology.
    Forsberg, Lina
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Microbiology.
    Roche, Niamh
    Ångström, Jonas
    Larsson, Thomas
    Teneberg, Susann
    Karlsson, Karl-Anders
    Altraja, Siiri
    Wadström, Torkel
    Kersulyte, Dangeruta
    Berg, Douglas E
    Dubois, Andre
    Petersson, Christoffer
    Magnusson, Karl-Eric
    Norberg, Thomas
    Lindh, Frank
    Lundskog, Bertil B
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Arnqvist, Anna
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Microbiology. Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Hammarström, Lennart
    Borén, Thomas
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Microbiology.
    Helicobacter pylori SabA adhesin in persistent infection and chronic inflammation2002In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 297, no 5581, p. 573-578Article in journal (Refereed)
    Abstract [en]

    Helicobacter pylori adherence in the human gastric mucosa involves specific bacterial adhesins and cognate host receptors. Here, we identify sialyl-dimeric-Lewis x glycosphingolipid as a receptor for H. pylori and show that H. pylori infection induced formation of sialyl-Lewis x antigens in gastric epithelium in humans and in a Rhesus monkey. The corresponding sialic acid-binding adhesin (SabA) was isolated with the "retagging" method, and the underlying sabA gene (JHP662/HP0725) was identified. The ability of many H. pylori strains to adhere to sialylated glycoconjugates expressed during chronic inflammation might thus contribute to virulence and the extraordinary chronicity of H. pylori infection.

  • 229. Majhen, Dragomira
    et al.
    Calderon, Hugo
    Chandra, Naresh
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Alberto Fajardo, Carlos
    Rajan, Anandi
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Alemany, Ramon
    Custers, Jerome
    Adenovirus-based vaccines for fighting infectious diseases and cancer: progress in the field2014In: Human Gene Therapy, ISSN 1043-0342, E-ISSN 1557-7422, Vol. 25, no 4, p. 301-317Article, review/survey (Refereed)
    Abstract [en]

    The field of adenovirology is undergoing rapid change in response to increasing appreciation of the potential advantages of adenoviruses as the basis for new vaccines and as vectors for gene and cancer therapy. Substantial knowledge and understanding of adenoviruses at a molecular level has made their manipulation for use as vaccines and therapeutics relatively straightforward in comparison with other viral vectors. In this review we summarize the structure and life cycle of the adenovirus and focus on the use of adenovirus-based vectors in vaccines against infectious diseases and cancers. Strategies to overcome the problem of preexisting antiadenovirus immunity, which can hamper the immunogenicity of adenovirus-based vaccines, are discussed. When armed with tumor-associated antigens, replication-deficient and oncolytic adenoviruses can efficiently activate an antitumor immune response. We present concepts on how to use adenoviruses as therapeutic cancer vaccines and consider some of the strategies used to further improve antitumor immune responses. Studies that explore the prospect of adenoviruses as vaccines against infectious diseases and cancer are underway, and here we give an overview of the latest developments.

  • 230.
    Makoveichuk, Elena
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Physiological chemistry.
    Vorrsjö, Evelina
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Physiological chemistry.
    Olivecrona, Thomas
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Physiological chemistry.
    Olivecrona, Gunilla
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Physiological chemistry.
    Inactivation of lipoprotein lipase in 3T3-L1 adipocytes by angiopoietin-like protein 4 requires that both proteins have reached the cell surface2013In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 441, no 4, p. 941-946Article in journal (Refereed)
    Abstract [en]

    Lipoprotein lipase (LPL) and angiopoietin-like protein 4 (Angptl4) were studied in 3T3-L1 adipocytes. Transfections of the adipocytes with Angptl4 esiRNA caused reduction of the expression of Angptl4 to about one fourth of that in cells treated with vehicle only. This resulted in higher levels of LPL activity both on cell surfaces (heparin-releasable) and in the medium, while LPL activity within the cells remained unaffected. This demonstrated that even though both proteins are made in the same cell, Angptl4 does not inactivate LPL during intracellular transport. Most of the Angptl4 protein was present as covalent dimers and tetramers on cell surfaces, while within the cells there were only monomers. LPL gradually lost activity when incubated in medium, but there was no marked difference between conditioned medium from normal cells (rich in Angptl4) and medium after knockdown of Angptl4. Hence Angptl4 did not markedly accelerate inactivation of LPL in the medium. Experiments with combinations of different cells and media indicated that inactivation of LPL occurred on the surfaces of cells producing Angptl4. (C) 2013 Elsevier Inc. All rights reserved.

  • 231.
    Malisauskas, Mantas
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    The amyloid: structure, properties and application2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Protein aggregation, leading to the formation and depositions of amyloids, is a cause for a number of diseases such as Alzheimer’s and Creutzfeld-Jacob’s disease, systemic amyloidoses, type II diabetes and others . More than 20 proteins are associated with protein misfolding diseases and even a larger number of proteins can self-assemble into amyloid in vitro. Relating structural and functional properties of amyloid is of particular interest, as this will lead to the identification of the main factors and mechanisms involved in the process of protein misfolding and aggregation; consequently, this will provide a basis for developing new strategies to treat protein misfolding diseases. The aim of the thesis is to investigate structural aspects of amyloid formation and relate that to the functional properties of amyloid. The first paper describes the amyloid formation of equine lysozyme (EL). We have demonstrated that EL enters an amyloid forming pathways under conditions where the molten globule state is populated. We have found that the morphology of the amyloids depend on the calcium-binding to lysozyme, specifically the holo-protein assembles into short, linear protofilaments, while the apo-EL forms ring-shaped structures. The morphology of EL amyloid significantly differs from the amyloid fibrils of human and hen lysozymes. We have suggested that the stable alpha-helical core of EL, which remains structured in the molten globule intermediate, may obstruct the formation of fibrilar interface and therefore leads to assembly of short, curly fibrils and rings.In the second paper, we describe the cytotoxicity of EL amyloids. We have analysed the amyloid intermediates on the pathway towards amyloid fibrils. The sizes of amyloid oligomers were determined by atomic force microscopy (AFM) and the formation of cross-beta sheet was shown by thioflavin T (ThT) binding. The toxicity studies show that the oligomers formed during amyloid growth phase are toxic to a range of cell lines and cultures and the toxicity is size-dependant.The last manuscript describes a novel method for manufacturing of silver nanowires by the biotemplating using amyloid fibrils. The amyloid assembled from an abundant and cheap hen egg white lysozyme was used as a scaffold for casting ultrathin silver nanowires. We have manufactured nanowires with a diameter of 1.0-2.5 nm and up to 2 micrometers in length. Up to date, it is the thinnest silver nanowires produced by using biotemplating and at least one order of magnitude thinner than nanowires manufactured by chemical synthesis.

  • 232.
    Malisauskas, Mantas
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Darinskas, A
    Zamotin, Vladimir
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Gharibyan, Anna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Kostanyan, IA
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Intermediate amyloid oligomers of lysozyme: is their cytotoxicity a particular case or general rule for amyloid?2006In: Biochemistry (Mosc), ISSN 0006-2979, Vol. 71, no 5, p. 505-512Article in journal (Refereed)
  • 233.
    Malisauskas, Mantas
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Meskys, Rolandas
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Ultrathin silver nanowires produced by amyloid biotemplating2008In: Biotechnology progress (Print), ISSN 8756-7938, E-ISSN 1520-6033, Vol. 24, no 5, p. 1166-1170Article in journal (Refereed)
    Abstract [en]

    By using a self-assembled amyloid from lysozyme as biotemplate we produced an ultrathin silver wire of 1 nm diameter and up to 2 μm in length, which is at the limit attainable in nanobiotechnological manufacturing. We showed that 2,2,2-trifluoroethanol produces a dual effect: it reduces ionic silver to colloidal nanoparticles with a regular size, depending on the length of incubation, and induces fibrillar assembly into the amyloid scaffold, forming the hollow channel filled with silver.

  • 234.
    Malisauskas, Mantas
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Ostman, Johan
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Darinskas, Adas
    Zamotin, Vladimir
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Liutkevicius, Evaldas
    Lundgren, Erik
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Does the cytotoxic effect of transient amyloid oligomers from common equine lysozyme in vitro imply innate amyloid toxicity?2005In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 280, no 8, p. 6269-6275Article in journal (Refereed)
    Abstract [en]

    In amyloid diseases, it is not evident which protein aggregates induce cell death via specific molecular mechanisms and which cause damage because of their mass accumulation and mechanical properties. We showed that equine lysozyme assembles into soluble amyloid oligomers and protofilaments at pH 2.0 and 4.5, 57 degrees C. They bind thioflavin-T and Congo red similar to common amyloid structures, and their morphology was monitored by atomic force microscopy. Molecular volume evaluation from microscopic measurements allowed us to identify distinct types of oligomers, ranging from tetramer to octamer and 20-mer. Monomeric lysozyme and protofilaments are not cytotoxic, whereas the oligomers induce cell death in primary neuronal cells, primary fibroblasts, and the neuroblastoma IMR-32 cell line. Cytotoxicity was accessed by ethidium bromide staining, MTT reduction, and TUNEL assays. Primary cultures were more susceptible to the toxic effect induced by soluble amyloid oligomers than the neuroblastoma cell line. The cytotoxicity correlates with the size of oligomers; the sample incubated at pH 4.5 and containing larger oligomers, including 20-mer, appears to be more cytotoxic than the lysozyme sample kept at pH 2.0, in which only tetramers and octamers were found. Soluble amyloid oligomers may assemble into rings; however, there was no correlation between the quantity of rings in the sample and its toxicity. The cytotoxicity of transient oligomeric species of the ubiquitous protein lysozyme indicates that this is an intrinsic feature of protein amyloid aggregation, and therefore soluble amyloid oligomers can be used as a primary therapeutic target and marker of amyloid disease.

  • 235.
    Malisauskas, Mantas
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Zamotin, Vladimir
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Jass, Jana
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Noppe, Wim
    Dobson, Christopher M
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Amyloid protofilaments from the calcium-binding protein equine lysozyme: formation of ring and linear structures depends on pH and metal ion concentration2003In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 330, no 4, p. 879-890Article in journal (Refereed)
    Abstract [en]

    The calcium-binding equine lysozyme has been found to undergo conversion into amyloid fibrils during incubation in solution at acidic pH. At pH 4.5 and 57 °C, where equine lysozyme forms a partially unfolded molten globule state, the protein forms protofilaments with a width of ca. 2 nm. In the absence of Ca2+ the protofilaments are present as annular structures with a diameter of 40–50 nm. In the presence of 10 mM CaCl2 the protofilaments of equine lysozyme are straight or curved; they can assemble into thicker threads, but they do not appear to undergo circularisation. At pH 2.0, where the protein is more destabilised compared to pH 4.5, fibril formation occurs at 37 °C and 57 °C. At pH 2.0, both ring-shaped and linear protofilaments are formed, in which periodic repeats of ca 35 nm can be distinguished clearly. The rings constitute about 10% of all fibrillar species under these conditions and they are characterised by a larger diameter of 70–80 nm. All the structures bind Congo red and thioflavine T in a manner similar to fibrils associated with a variety of amyloid diseases. At pH 2.0, fibril formation is accompanied by some acidic hydrolysis, producing specific fragmentation of the protein, leading to the accumulation of two peptides in particular, consisting of residues 1–80 and 54–125. At the initial stages of incubation, however, full-length equine lysozyme represents the dominant species within the fibrils. We propose that the ring-shaped structures observed here, and in the case of disease-associated proteins such as -synuclein, could be a second generic type of amyloid structure in addition to the more common linear fibrils.

  • 236.
    Malm, Linus
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Size determination of hyaluronan and multivariate analysis of amyloid prone proteins2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background.The extracellular matrix surrounds all cells within our bodies. The glycosaminoglycan hyaluronan is a major component in the extracellular matrix. Despite its structural simplicity it has been shown to be involved in several important functions. It is a lubricant and shock absorber, as well as an important player in inflammation and tumor invasion. Many of its functions are closely related to its size and concentration in tissues. Therefore methods for measuring these properties are of great importance to properly understand the role that hyaluronan play in different events. Proteins are found both inside and outside cells, and they have a wide variety of functions. The protein structure and function is determined by the properties of their building blocks, the amino acids. Several diseases have been linked to changes in the amino acid sequence of certain proteins by mutations, causing the proteins to form extracellular deposits of structures called amyloid aggregates. The aim of this thesis is to investigate the function of hyaluronan in cell cultures, develop new methods for size determination hyaluronan and to use multivariate methods to provide prediction and better understanding of factors driving protein amyloid aggregation.

    Methods.Cardiomyocytes and fibroblast were cultured and stimulated by different growth factors. Hyaluronan was purified and its size and concentration were measured. Crosstalk between cardiomyocytes and fibroblast were investigated and gene expression of hyaluronan synthases was determined. A new method for size measurement of hyaluronan was developed. The amyloid aggregation rate of different mutants of acylphosphatase was predicted by multivariate analysis.

    Results. Cardiomyocytes stimulated by PDGF-BB produced hyaluronan. Cardiomyocytes could induce fibroblast to increase its hyaluronan production, through an unknown soluble factor. The cardiomyocyte gene expression changed when stimulated by hyaluronan. GEMMA was presented as a new method for size determination of hyaluronan. Amyloid aggregation of different acylphosphatase mutants could be predicted using a multivariate regression model of the physicochemical and structural properties of the amino acid sequence.

    Conclusion. It was shown that cardiomyocytes are not only able to produce hyaluronan, but also induce an increased hyaluronan production in other cells. GEMMA was proven suitable for size determination of hyaluronan at very low concentrations. Multivariate analysis showed that hydrophobic patterns and charge where the most important factors for amyloid aggregation of acylphosphatase.

  • 237.
    Mandel, Anna
    et al.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Larsson, Per
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Sarwar, Martuza
    Semenas, Julius
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Khaja, Azharuddin Sajid Syed
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Persson, Jenny L.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    The interplay between AR, EGF receptor and MMP-9 signaling pathways in invasive prostate cancer2018In: Molecular medicine (Cambridge, Mass. Print), ISSN 1076-1551, E-ISSN 1528-3658, Vol. 24, p. 1-13, article id UNSP 34Article in journal (Refereed)
    Abstract [en]

    Background: Metastatic Prostate cancer (PCa) cells have gained survival and invasive advantages. Epidermal growth factor (EGA) receptor is a receptor tyrosine kinase, which may mediate signalling to promote progression and invasion of various cancers. In this study, we uncovered the molecular mechanisms underlying the interconnection among the androgen receptor (AR), matrix metalloproteinase-9 (MMP9) and EGFR in promoting PCa progression. Methods: Immunohistochemical analysis of the tissue microarrays consisting of primary and metastatic PCa tissues was performed. The clinical importance of EGFR and its association with survivals were analyzed using three cohorts from MSKCC Prostate Oncogenome Project dataset (For primary tumors, n = 181; for metastatic tumors n = 37) and The Cancer Genome Atlas Prostate Adenocarcinoma Provisional dataset (n = 495). Targeted overexpression or inhibition of the proteins of interests was introduced into PCa cell lines. Treatment of PCa cell lines with the compounds was conducted. Immunoblot analysis was performed. Results: We showed that AR, MMP-9 and EGFR are interconnect factors, which may cooperatively promote PCa progression. Altered EGFR expression was associated with poor disease-free survival in PCa patients. Induced overexpression of AR led to an increase in the expression of EGFR, p-GSK-313 and decrease in p27 expression in PCa cell lines in the presence of androgen stimulation. Overexpression of MMP9 significantly induced EGFR expression in PCa cells. Inhibition of PIP5K1a, a lipid kinase that acts upstream of PI3K/AKT greatly reduced expressions of AR, MMP-9 and EGFR. Conclusions: Our findings also suggest that PCa cells may utilize AR, EGFR and MMP-9 pathways in androgen-dependent as well as in castration-resistant conditions. Our data suggest a new therapeutic potential to block cancer metastasis by targeting AR, EGFR and MMP-9 pathways in subsets of PCa patients.

  • 238.
    Mantovani, Cristina
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Mahay, Daljeet
    Kingham, Paul J
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Terenghi, Giorgio
    Shawcross, Susan G
    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.
    Bone marrow- and adipose-derived stem cells show expression of myelin mRNAs and proteins2010In: Regenerative medicine, ISSN 1746-076X, Vol. 5, no 3, p. 403-410Article in journal (Refereed)
    Abstract [en]

    Aims: PNS myelin is formed by Schwann cells (SCs). In this study, we applied an in vitro model to study myelin formation, using bone marrow mesenchymal stem cells and adipose-derived stem cells differentiated into SC-like cells and co-cultured with dissociated adult dorsal root ganglia neurons.

    Methods: Immunocytochemistry, reverse transcription-PCR and western blotting techniques were used to investigate the expression of myelin proteins at both the transcriptional and translational level.

    Results: Transcripts for protein zero, peripheral myelin protein 22 and myelin basic protein were detected in differentiated stem cells following co-culture with neuronal cells. Furthermore, protein zero, peripheral myelin protein 22 and myelin basic proteins were recognized in the co-cultures. These results were consistent with immunostaining of myelin proteins and with observation by electron microscopy.

    Conclusion: Both types of adult stems cells differentiated into SC-like cells have potential to myelinate neuronal cells during regeneration, being functionally identical to SCs of the PNS.

  • 239.
    Mantovani, Cristina
    et al.
    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. University of Manchester.
    Raimondo, Stefania
    University of Turin.
    Haneef, Maryam S.
    University of Manchester.
    Geuna, Stefano
    University of Turin.
    Terenghi, Giorgio
    University of Manchester.
    Shawcross, Susan G.
    University of Manchester.
    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.
    Morphological, molecular and functional differences of adult bone marrow- and adipose-derived stem cells isolated from rats of different ages2012In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 318, no 16, p. 2034-2048Article in journal (Refereed)
    Abstract [en]

    Adult mesenchymal stem cells have self-renewal and multiple differentiation potentials, and play important roles in regenerative medicine. However, their use may be limited by senescence or age of the donor, leading to changes in stem cell functionality. We investigated morphological, molecular and functional differences between bone marrow-derived (MSC) and adipose-derived (ASC) stem cells isolated from neonatal, young and old rats compared to Schwann cells from the same animals. Immunocytochemistry, RT-PCR, proliferation assays, western blotting and transmission electron microscopy were used to investigate expression of senescence markers. Undifferentiated and differentiated ASC and MSC from animals of different ages expressed Notch-2 at similar levels; protein-38 and protein-53 were present in all groups of cells with a trend towards increased levels in cells from older animals compared to those from neonatal and young rats. Following co-culture with adult neuronal cells, dMSC and dASC from animals of all ages elicited robust neurite outgrowth. Mitotracker (R) staining was consistent with ultrastructural changes seen in the mitochondria of cells from old rats, indicative of senescence. In conclusion, this study showed that although the cells from aged animals expressed markers of senescence, aged MSC and ASC differentiated into SC-like cells still retain potential to support axon regeneration.

  • 240.
    Mantovani, Maria Cristina
    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.
    Schwann cells and mesenchymal stem cells as promoter of peripheral nerve regeneration2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The transplantation of primary Schwann cells (SC) has been shown to improve nerve regeneration. However, to monitor the survival of transplanted cells within the host, a stable labelling method is required. The in vitro characteristics of green fluorescent protein labelled SC (GFP SC) and their effects in an in vivo peripheral nerve injury model were investigated.   The GFP-SC were readily visualised ex vivo and stimulated significantly better axonal regeneration compared to controls. Clinical use of autologous SC for the treatment of nerve injuries is of limited use due to difficulty in obtaining clinically useful numbers. However, bone marrow mesenchymal stem cells (MSC) can trans-differentiate into SC like cells (dMSC). The in vitro and in vivo differentiation of MSC was explored, and the study extended to include the easily-accessible adipose stem cells (ASC).  In vitro, glial growth factor stimulated MSC express S100, a SC marker, and its expression is maintained following in vivo transplantation.  Similarly, untreated MSC transplanted in vivo also expressed S100, which indicates glial differentiation in response to local cytokines and growth factors. Using an in vitro model, comprising dMSC or dASC co-cultured with adult dorsal root ganglia (DRG) neurons, the capacity of the dMSC and SC like differentiated ASC (dASC) to promote axon myelination was verified: both cell types expressed transcripts for protein zero, peripheral myelin protein-22 and myelin basic protein.

    The potential of stem cells in nerve repair may be limited by innate cellular senescence or donor age affecting cell functionality thus it was essential to determine the effects of donor age on morphology and functionality of stem cells.  The proliferation rates, expression of senescence markers (p38 and p53) and the stimulation of neurite outgrowth from DRG neurons by stem cells isolated from neonatal, young or old rats were very similar. However, the distribution and ultrastructure of mitochondria in dMSC and dASC from young and old rats were quite different, and seem to indicate physiological senescence of the aged cells.  Given the wide-ranging influence of Notch signalling in cell differentiation, including the neural crest to a glial cell type switch, and self-renewal in mammals, its role in the differentiation of stem cells to SC was investigated. The mRNA for notch-1 and -2 receptors were expressed in the dASC, blockage of notch signaling did not affect the neurotrophic and myelination potential of dASC. 

    In conclusion, these findings show that GFP labelling has no deleterious effect on SC survival and function. MSC and ASC differentiated into glial-type cells acquire SC morphology, and express characteristic SC markers, and the differentiation process was independent of the Notch signaling pathway. Also, following transplantation into a nerve gap injury dMSC improve regeneration. This study established that following co-culture with DRG neurons, dMSC and dASC were able to express peripheral myelin proteins.  Also, the functional bioactivity of these cells is independent of the donor animal age. Finally, although the glial lineage differentiated aged cells characterized in this study expressed markers typical of senescence they retained the potential to support axon regeneration.

  • 241.
    Marklund, Stefan
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Hydroxymethylhydroperoxide and bis(hydroxymethyl)peroxide and their effects on certain enzymes, especially horseradish peroxidase.1972Doctoral thesis, comprehensive summary (Other academic)
  • 242. Martinez, Nancy E.
    et al.
    Zimmermann, Tobias J.
    Goosmann, Christian
    Alexander, Tobias
    Hedberg, Christian
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Ziegler, Slava
    Zychlinsky, Arturo
    Waldmann, Herbert
    Tetrahydroisoquinolines: New Inhibitors of Neutrophil Extracellular Trap (NET) Formation2017In: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 18, no 10, p. 888-893Article in journal (Refereed)
    Abstract [en]

    Neutrophils are short-lived leukocytes that migrate to sites of infection as part of the acute immune response, where they phagocytose, degranulate, and form neutrophil extracellular traps (NETs). During NET formation, the nuclear lobules of neutrophils disappear and the chromatin expands and, accessorized with neutrophilic granule proteins, is expelled. NETs can be pathogenic in, for example, sepsis, cancer, and autoimmune and cardiovascular diseases. Therefore, the identification of inhibitors of NET formation is of great interest. Screening of a focused library of natural-product-inspired compounds by using a previously validated phenotypic NET assay identified a group of tetrahydroisoquinolines as new NET formation inhibitors. This compound class opens up new avenues for the study of cellular death through NET formation (NETosis) at different stages, and might inspire new medicinal chemistry programs aimed at NET-dependent diseases.

  • 243.
    Matilda, Rentoft
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    The use of formalin fixed paraffin embedded tissue and global gene expression profiling for increased understanding of squamous cell carcinoma of the tongue2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Head and neck cancer is the 6th most common malignancy worldwide, with tumours of the tongue being one of the most prevalent sites. Despite advances in surgery and radiotherapy, the five-year survival has not changed during the last decades and remains at approximately 50%. Identification of novel biomarkers for more personalized treatment is important for increasing survival in these patients. One of the most commonly used methods in the search for new biomarkers is microarray analysis. A substantial limitation with this technique is the requirement for fresh frozen samples from which high quality RNA can be extracted. This becomes particularly problematic when attempting to discover differences associated with individual sub-types or rare cancers. Recent developments, including the DASL microarray platform, have provided the possibility of analysing RNA of poorer quality from formalin fixed paraffin embedded (FFPE) samples. FFPE is the standard way of preserving tissue from patients and millions of samples are stored around the world. In this thesis we have evaluated the use of FFPE samples and global gene expression profiling for increasing basic knowledge in a subgroup of oral cancer patients with tumours of the tongue.

    As confirmation of microarray results using qPCR is of outmost importance for conclusive data evaluation, we first aimed at finding a housekeeping gene stably expressed across malignant and non-malignant FFPE oral tissue. TUBA6, which belongs to the tubulin family was detected as being the most stable out of eight possible genes and was thus used for qPCR normalization throughout the following studies.

    We have performed three separate microarray experiments. Initially only a focused DASL array covering 502 cancer related genes was available and we used it to analyze a smaller cohort of patients and controls (n=36). A similar cohort (n=29) was also analyzed for expression of 836 micoRNAs. In 2009 a whole genome DASL array was launched, covering over 20,000 genes, and all tongue tumour samples available between 1997 and 2010 (n=87) were analysed using this array.

    Similar to other research groups we observed very high replicate reproducibility using both DASL arrays. When using the microRNA array and the whole genome DASL array an effect of sample quality on the detected expression level of individual genes was noticed. While the expression of some genes severely decreased with a decrease in sample quality others were not changed. This will impair normalization, leading to a residual non-biological variation within the data. Based on our findings we have presented some recommendations for minimizing the effect of sample quality and maximizing the level of biologically relevant information obtained from these experiments, e.g. ensuring that samples in groups to be compared are of the same quality range. For the microRNA data we also introduced an additional normalization step to the standard normalizations. We could show that lists of differentially expressed genes generated when taking these precautions were enriched for genes involved in cancer related processes and contained for tongue carcinoma previously identified changes. A number of differentially expressed genes, novel for tongue carcinoma, were also confirmed in high quality fresh frozen samples, including BCL2A1 (apoptosis), CXCL10 (immune response), SLC2A6 (energy transport) and miR-424 (angiogenesis).

    In conclusion microarrays can be used to analyze FFPE samples but should be performed with care. Standard normalization methods will not remove the variation introduced by samples being of different quality, leading to spurious results. Taking a few precautions, however, led to the identification of differentially expressed genes relevant in tumour development and maintenance. The recommendations we make can facilitate design of future studies using FFPE samples. The genes we identified as being differentially expressed in tumour tissue now need to be further evaluated for their potential as biomarkers in tongue carcinoma.

  • 244.
    Mayans, Sofia
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Medical and Clinical Genetics.
    Lackovic, Kurt
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Medical and Clinical Genetics.
    Lindgren, Petter
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Medical and Clinical Genetics.
    Ruikka, Karin
    Department of Medicine, Sunderby Hospital, Luleå.
    Ågren, Åsa
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Nutritional Research. Umeå University, Faculty of Medicine, Department of Biobank Research.
    Eliasson, Mats
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine. Department of Medicine, Sunderby Hospital, Luleå.
    Holmberg, Dan
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Medical and Clinical Genetics. Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    TCF7L2 polymorphisms are associated with type 2 diabetes in northern Sweden2007In: European Journal of Human Genetics, ISSN 1018-4813, E-ISSN 1476-5438, Vol. 15, no 3, p. 342-346Article in journal (Refereed)
    Abstract [en]

    A recent study found association of one microsatellite and five single nucleotide polymorphisms (SNPs) in intron 3 of the TCF7L2 gene with type 2 diabetes (T2D) in the Icelandic, Danish and American populations. The aim of the present study was to investigate if those SNPs were associated to T2D in two (family- and population-based) cohorts from northern Sweden. We genotyped four of the associated SNPs in a case-control cohort consisting of 872 T2D cases and 857 controls matched with respect to age, sex and geographical origin and in a sample of 59 extended families (148 affected and 83 unaffected individuals). Here, we report replication of association between T2D and three SNPs in the case-control (rs7901695, P=0.003; rs7901346, P=0.00002; and rs12255372, P=0.000004) and two SNPs in the family-based (rs7901695, P=0.01 and rs7901346, P=0.04) samples from northern Sweden. This replication strengthens the evidence for involvement of TCF7L2 in T2D.

  • 245.
    Medini, Paolo
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Experience-dependent plasticity of visual cortical microcircuits2014In: Neuroscience, ISSN 0306-4522, E-ISSN 1873-7544, Vol. 278, p. 367-384Article, review/survey (Refereed)
    Abstract [en]

    The recent decade testified a tremendous increase in our knowledge on how cell-type-specific microcircuits process sensory information in the neocortex and on how such circuitry reacts to manipulations of the sensory environment. Experience-dependent plasticity has now been investigated with techniques endowed with cell resolution during both postnatal development and in adult animals. This review recapitulates the main recent findings in the field using mainly the primary visual cortex as a model system to highlight the more important questions and physiological principles (such as the role of non-competitive mechanisms, the role of inhibition in excitatory cell plasticity, the functional importance of spine and axonal plasticity on a microscale level). I will also discuss on which scientific problems the debate and controversies are more pronounced. New technologies that allow to perturbate cell-type-specific subcircuits will certainly shine new light in the years to come at least on some of the still open questions. (C) 2014 The Author. Published by Elsevier Ltd. on behalf of IBRO.

  • 246.
    Mei, Ya-Fang
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Silver, Jim
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Completely replication-competent adenovirus 11p GFP (RCAd11pGFP) vector with an insertion upstream of the full-length E1 regionArticle in journal (Other academic)
  • 247. Melo, Arthur Alves
    et al.
    Hegde, Balachandra G.
    Shah, Claudio
    Larsson, Elin
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Isas, J. Mario
    Kunz, Severine
    Lundmark, Richard
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Langen, Ralf
    Daumke, Oliver
    Structural insights into the activation mechanism of dynamin-like EHD ATPases2017In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 114, no 22, p. 5629-5634Article in journal (Refereed)
    Abstract [en]

    Eps15 (epidermal growth factor receptor pathway substrate 15)homology domain containing proteins (EHDs) comprise a family of dynamin-related mechano-chemical ATPases involved in cellular membrane trafficking. Previous studies have revealed the structure of the EHD2 dimer, but the molecular mechanisms of membrane recruitment and assembly have remained obscure. Here, we determined the crystal structure of an amino-terminally truncated EHD4 dimer. Compared with the EHD2 structure, the helical domains are 50 degrees rotated relative to the GTPase domain. Using electron paramagnetic spin resonance (EPR), we show that this rotation aligns the two membrane-binding regions in the helical domain toward the lipid bilayer, allowing membrane interaction. A loop rearrangement in GTPase domain creates a new interface for oligomer formation. Our results suggest that the EHD4 structure represents the active EHD conformation, whereas the EHD2 structure is autoinhibited, and reveal a complex series of domain rearrangements accompanying activation. A comparison with other peripheral membrane proteins elucidates common and specific features of this activation mechanism.

  • 248. Messing, Jutta
    et al.
    Niehues, Michael
    Shevtsova, Anna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Boren, Thomas
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Hensel, Andreas
    Antiadhesive Properties of Arabinogalactan Protein from Ribes nigrum Seeds against Bacterial Adhesion of Helicobacter pylori2014In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 19, no 3, p. 3696-3717Article in journal (Refereed)
    Abstract [en]

    Fruit extracts from black currants (Ribes nigrum L.) are traditionally used for treatment of gastritis based on seed polysaccharides that inhibit the adhesion of Helicobacter pylori to stomach cells. For detailed investigations an arabinogalactan protein (F2) was isolated from seeds and characterized concerning molecular weight, carbohydrate, amino acid composition, linkage, configuration and reaction with beta-glucosyl Yariv. Functional testing of F2 was performed by semiquantitative in situ adhesion assay on sections of human gastric mucosa and by quantitative in vitro adhesion assay with FITC-labled H. pylori strain J99 and human stomach AGS cells. Bacterial adhesins affected were identified by overlay assay with immobilized ligands. I-125-radiolabeled F2 served for binding studies to H. pylori and interaction experiments with BabA and SabA. F2 had no cytotoxic effects against H. pylori and AGS cells; but inhibited bacterial binding to human gastric cells. F2 inhibited the binding of BabA and fibronectin-binding adhesin to its specific ligands. Radiolabeled F2 bound non-specifically to different strains of H. pylori; and to BabA deficient mutant. F2 did not lead to subsequent feedback regulation or increased expression of adhesins or virulence factors. From these data the non-specific interactions between F2 and the H. pylori lead to moderate antiadhesive effects.

  • 249. Metzler, Veronika M.
    et al.
    de Brot, Simone
    Robinson, Robert S.
    Jeyapalan, Jennie N.
    Rakha, Emad
    Walton, Thomas
    Gardner, David S.
    Lund, Emma F.
    Whitchurch, Jonathan
    Haigh, Daisy
    Lochray, Jack M.
    Robinson, Brian D.
    Allegrucci, Cinzia
    Fray, Rupert G.
    Persson, Jenny L.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Department of Translational Medicine, Lund University, Malmo, Sweden.
    Odum, Niels
    Miftakhova, Regina R.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Kazan Federal University, Kazan, Republic of Tatarstan, Russian Federation.
    Rizvanov, Albert A.
    Hughes, Ieuan A.
    Tadokoro-Cuccaro, Rieko
    Heery, David M.
    Rutland, Catrin S.
    Mongan, Nigel P.
    Androgen dependent mechanisms of pro-angiogenic networks in placental and tumor development2017In: Placenta, ISSN 0143-4004, E-ISSN 1532-3102, Vol. 56, p. 79-85Article in journal (Refereed)
    Abstract [en]

    The placenta and tumors share important characteristics, including a requirement to establish effective angiogenesis. In the case of the placenta, optimal angiogenesis is required to sustain the blood flow required to maintain a successful pregnancy, whereas in tumors establishing new blood supplies is considered a key step in supporting metastases. Therefore the development of novel angiogenesis inhibitors has been an area of active research in oncology. A subset of the molecular processes regulating angiogenesis are well understood in the context of both early placentation and tumorigenesis. In this review we focus on the well-established role of androgen regulation of angiogenesis in cancer and relate these mechanisms to placental angiogenesis. The physiological actions of androgens are mediated by the androgen receptor (AR), a ligand dependent transcription factor. Androgens and the AR are essential for normal male embryonic development, puberty and lifelong health. Defects in androgen signalling are associated with a diverse range of clinical disorders in men and women including disorders of sex development (DSD), polycystic ovary syndrome in women and many cancers. We summarize the diverse molecular mechanisms of androgen regulation of angiogenesis and infer the potential significance of these pathways to normal and pathogenic placental function. Finally, we offer potential research applications of androgen-targeting molecules developed to treat cancer as investigative tools to help further delineate the role of androgen signalling in placental function and maternal and offspring health in animal models.

  • 250. Meyer, Barbara J.
    et al.
    Stewart, Frances M.
    Brown, Elizabeth A.
    Cooney, Josephine
    Nilsson, Solveig
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Physiological chemistry.
    Olivecrona, Gunilla
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Physiological chemistry.
    Ramsay, Jane E.
    Griffin, Bruce A.
    Caslake, Muriel J.
    Freeman, Dilys J.
    Maternal Obesity Is Associated With the Formation of Small Dense LDL and Hypoadiponectinemia in the Third Trimester2013In: Journal of Clinical Endocrinology and Metabolism, ISSN 0021-972X, E-ISSN 1945-7197, Vol. 98, no 2, p. 643-652Article in journal (Refereed)
    Abstract [en]

    Context: Maternal obesity is associated with high plasma triglyceride, poor vascular function, and an increased risk for pregnancy complications. In normal-weight pregnant women, higher triglyceride is associated with increased small, dense low-density lipoprotein (LDL). Hypothesis: In obese pregnancy, increased plasma triglyceride concentrations result in triglyceride enrichment of very low-density lipoprotein-1 particles and formation of small dense LDL via lipoprotein lipase. Design: Women (n = 55) of body mass index of 18-46 kg/m(2) were sampled longitudinally at 12, 26, and 35 weeks' gestation and 4 months postnatally. Setting: Women were recruited at hospital antenatal appointments, and study visits were in a clinical research suite. Outcome Measures: Plasma concentrations of lipids, triglyceride-rich lipoproteins, lipoprotein lipase mass, estradiol, steroid hormone binding globulin, insulin, glucose, leptin, and adiponectin were determined. Results: Obese women commenced pregnancy with higher plasma triglyceride, reached the same maximum, and then returned to higher postnatal levels than normal-weight women. Estradiol response to pregnancy (trimester 1-3 incremental area under the curve) was positively associated with plasma triglyceride response (r(2) adjusted 25%, P < .001). In the third trimester, the proportion of small, dense LDL was 2-fold higher in obese women than normal-weight women[mean (SD) 40.7 (18.8) vs 21.9 (10.9)%, P = .014], and 35% of obese, 14% of overweight, and none of the normal-weight women displayed an atherogenic LDL subfraction phenotype. The small, dense LDL mass response to pregnancy was inversely associated with adiponectin response (17%, P = .013). Conclusions: Maternal obesity is associated with an atherogenic LDL subfraction phenotype and may provide a mechanistic link to poor vascular function and adverse pregnancy outcome.

2345678 201 - 250 of 419
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf