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  • 1. Abbara, Aula
    et al.
    Al-Harbat, Nizar
    Karah, Nabil
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Abo-Yahya, Bashar
    El-Amin, Wael
    Hatcher, James
    Gabbar, Omar
    Antimicrobial Drug Resistance among Refugees from Syria, Jordan2017Inngår i: Emerging Infectious Diseases, ISSN 1080-6040, E-ISSN 1080-6059, Vol. 23, nr 5, s. 885-886Artikkel i tidsskrift (Fagfellevurdert)
  • 2.
    Abdulamir, Dalia
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Evaluation of the Role of Histidines Regarding the Self-assembly and Fibrillar Stability of Amyloid βeta2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
  • 3.
    Abdullah Nasir, Ahmad
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Herdenberg, Carl
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Hedman, Håkan
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi. Oncology Research Laboratory, NUS M31, Umeå, Sweden.
    Netrin-1 functions as a suppressor of bone morphogenetic protein (BMP) signaling2021Inngår i: Scientific Reports, E-ISSN 2045-2322, Vol. 11, nr 1, artikkel-id 8585Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Netrin-1 is a secreted protein that is well known for its involvement in axonal guidance during embryonic development and as an enhancer of cancer cell metastasis. Despite extensive efforts, the molecular mechanisms behind many of the physiological functions of netrin-1 have remained elusive. Here, we show that netrin-1 functions as a suppressor of bone morphogenetic protein (BMP) signaling in various cellular systems, including a mutually inhibitory interaction with the BMP-promoting function of leucine-rich repeats and immunoglobulin-like domains (LRIG) proteins. The BMP inhibitory function of netrin-1 in mouse embryonic fibroblasts was dependent on the netrin receptor neogenin, with the expression level regulated by both netrin-1 and LRIG proteins. Our results reveal a previously unrecognized function of netrin-1 that may help to explain several of the developmental, physiological, and cancer-promoting functions of netrins at the signal transduction level.

    Fulltekst (pdf)
    fulltext
  • 4.
    Abidine, Yara
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi. Umeå universitet, Medicinska fakulteten, Wallenberg centrum för molekylär medicin vid Umeå universitet (WCMM).
    Liu, Lifeng
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi. Umeå universitet, Medicinska fakulteten, Wallenberg centrum för molekylär medicin vid Umeå universitet (WCMM).
    Wallén, Oskar
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi.
    Trybala, Edward
    Department of Infectious Diseases, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden.
    Olofsson, Sigvard
    Department of Infectious Diseases, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden.
    Bergström, Tomas
    Department of Infectious Diseases, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden.
    Bally, Marta
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi. Umeå universitet, Medicinska fakulteten, Wallenberg centrum för molekylär medicin vid Umeå universitet (WCMM).
    Cellular Chondroitin Sulfate and the Mucin-like Domain of Viral Glycoprotein C Promote Diffusion of Herpes Simplex Virus 1 While Heparan Sulfate Restricts Mobility2022Inngår i: Viruses, E-ISSN 1999-4915, Vol. 14, nr 8, artikkel-id 1836Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The diffusion of viruses at the cell membrane is essential to reach a suitable entry site and initiate subsequent internalization. Although many viruses take advantage of glycosaminoglycans (GAG) to bind to the cell surface, little is known about the dynamics of the virus–GAG interactions. Here, single-particle tracking of the initial interaction of individual herpes simplex virus 1 (HSV-1) virions reveals a heterogeneous diffusive behavior, regulated by cell-surface GAGs with two main diffusion types: confined and normal free. This study reports that different GAGs can have competing influences in mediating diffusion on the cells used here: chondroitin sulfate (CS) enhances free diffusion but hinders virus attachment to cell surfaces, while heparan sulfate (HS) promotes virus confinement and increases entry efficiency. In addition, the role that the viral mucin-like domains (MLD) of the HSV-1 glycoprotein C plays in facilitating the diffusion of the virus and accelerating virus penetration into cells is demonstrated. Together, our results shed new light on the mechanisms of GAG-regulated virus diffusion at the cell surface for optimal internalization. These findings may be extendable to other GAG-binding viruses.

    Fulltekst (pdf)
    fulltext
  • 5. Abraham, Nabil M.
    et al.
    Liu, Lei
    Jutras, Brandon Lyon
    Yadav, Akhilesh K.
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten). Umeå universitet, Medicinska fakulteten, Molekylär Infektionsmedicin, Sverige (MIMS).
    Narasimhan, Sukanya
    Gopalakrishnan, Vissagan
    Ansari, Juliana M.
    Jefferson, Kimberly K.
    Cava, Felipe
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten). Umeå universitet, Medicinska fakulteten, Molekylär Infektionsmedicin, Sverige (MIMS).
    Jacobs-Wagner, Christine
    Fikrig, Erol
    Pathogen-mediated manipulation of arthropod microbiota to promote infection2017Inngår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 114, nr 5, s. E781-E790Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Arthropods transmit diverse infectious agents; however, the ways microbes influence their vector to enhance colonization are poorly understood. Ixodes scapularis ticks harbor numerous human pathogens, including Anaplasma phagocytophilum, the agent of human granulocytic anaplasmosis. We now demonstrate that A. phagocytophilum modifies the I. scapularis microbiota to more efficiently infect the tick. A. phagocytophilum induces ticks to express Ixodes scapularis antifreeze glycoprotein (iafgp), which encodes a protein with several properties, including the ability to alter bacterial biofilm formation. IAFGP thereby perturbs the tick gut microbiota, which influences the integrity of the peritrophic matrix and gut barrier-critical obstacles for Anaplasma colonization. Mechanistically, IAFGP binds the terminal D-alanine residue of the pentapeptide chain of bacterial peptidoglycan, resulting in altered permeability and the capacity of bacteria to form biofilms. These data elucidate the molecular mechanisms by which a human pathogen appropriates an arthropod antibacterial protein to alter the gut microbiota and more effectively colonize the vector.

  • 6.
    Achour, Cyrinne
    et al.
    Umeå universitet, Medicinska fakulteten, Wallenberg centrum för molekylär medicin vid Umeå universitet (WCMM). Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Aguilo, Francesca
    Umeå universitet, Medicinska fakulteten, Wallenberg centrum för molekylär medicin vid Umeå universitet (WCMM). Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Long non-coding RNA and Polycomb: an intricate partnership in cancer biology2018Inngår i: Frontiers in Bioscience, ISSN 1093-9946, E-ISSN 1093-4715, Vol. 23, s. 2106-2132Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High-throughput analyses have revealed that the vast majority of the transcriptome does not code for proteins. These non-translated transcripts, when larger than 200 nucleotides, are termed long non-coding RNAs (lncRNAs), and play fundamental roles in diverse cellular processes. LncRNAs are subject to dynamic chemical modification, adding another layer of complexity to our understanding of the potential roles that lncRNAs play in health and disease. Many lncRNAs regulate transcriptional programs by influencing the epigenetic state through direct interactions with chromatin-modifying proteins. Among these proteins, Polycomb repressive complexes 1 and 2 (PRC1 and PRC2) have been shown to be recruited by lncRNAs to silence target genes. Aberrant expression, deficiency or mutation of both lncRNA and Polycomb have been associated with numerous human diseases, including cancer. In this review, we have highlighted recent findings regarding the concerted mechanism of action of Polycomb group proteins (PcG), acting together with some classically defined lncRNAs including X-inactive specific transcript (XIST), antisense non-coding RNA in the INK4 locus (ANRIL), metastasis associated lung adenocarcinoma transcript 1 (MALAT1), and HOX transcript antisense RNA (HOTAIR).

  • 7.
    Achour, Cyrinne
    et al.
    Umeå universitet, Medicinska fakulteten, Wallenberg centrum för molekylär medicin vid Umeå universitet (WCMM). Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Aguilo, Francesca
    Umeå universitet, Medicinska fakulteten, Wallenberg centrum för molekylär medicin vid Umeå universitet (WCMM). Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Long Noncoding RNAs as Players in Breast Tumorigenesis2020Inngår i: The chemical biology of long noncoding RNAs / [ed] Stefan Jurga, Jan Barciszewski, Springer, 2020, , s. 19s. 385-403Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Comprehensive analysis of the mammalian genome uncovered the discovery of pervasive transcription of large RNA transcripts that do not code for proteins, namely, long noncoding RNAs (lncRNAs). LncRNAs play important roles in the regulation of gene expression from integration of chromatin remodeling complexes to transcriptional and posttranscriptional regulation of protein-coding genes. Application of next-generation sequencing technologies to cancer transcriptomes has revealed that aberrant expression of lncRNAs is associated with tumor progression and metastasis. Although thousands of lncRNAs have been shown to be dysregulated in different cancer types, just few of them have been fully characterized. In this book chapter, we aim to highlight recent findings of the mechanistic function of lncRNAs in breast cancer and summarize key examples of lncRNAs that are misregulated during breast tumorigenesis. We have categorized breast cancer–associated lncRNA according to their contribution to tumor suppression or tumor progression based on recent studies. Because some of them are expressed in a specific molecular breast cancer subtype, we have outlined lncRNAs that can potentially serve as diagnostic and prognostic markers, in which expression is linked to chemotherapy resistance. Finally, we have discussed current limitations and perspectives on potential lncRNA targets for use in therapies against breast cancer.

  • 8. Agrawal, Ganesh Kumar
    et al.
    Sarkar, Abhijit
    Agrawal, Raj
    Ndimba, Bongani Kaiser
    Tanou, Georgia
    Dunn, Michael J
    Kieselbach, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Cramer, Rainer
    Wienkoop, Stefanie
    Chen, Sixue
    Rafudeen, Mohammed Suhail
    Deswal, Renu
    Barkla, Bronwyn J
    Weckwerth, Wolfram
    Heazlewood, Joshua L
    Renaut, Jenny
    Job, Dominique
    Chakraborty, Niranjan
    Rakwal, Randeep
    Boosting the Globalization of Plant Proteomics through INPPO: Current Developments and Future Prospects2012Inngår i: Proteomics, ISSN 1615-9853, E-ISSN 1615-9861, Vol. 12, nr 3, s. 359-368Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The International Plant Proteomics Organization (INPPO) is a non-profit-organization consisting of people who are involved or interested in plant proteomics. INPPO is constantly growing in volume and activity, which is mostly due to the realization among plant proteomics researchers worldwide for the need of such a global platform. Their active participation resulted in the rapid growth within the first year of INPPO's official launch in 2011 via its website (www.inppo.com) and publication of the 'Viewpoint paper' in a special issue of PROTEOMICS (May 2011). Here, we will be highlighting the progress achieved in the year 2011 and the future targets for the year 2012 and onwards. INPPO has achieved a successful administrative structure, the Core Committee (CC; composed of President, Vice-President, and General Secretaries), Executive Council (EC), and General Body (GB) to achieve INPPO objectives. Various committees and subcommittees are in the process of being functionalized via discussion amongst scientists around the globe. INPPO's primary aim to popularize the plant proteomics research in biological sciences has also been recognized by PROTEOMICS where a section dedicated to plant proteomics has been introduced starting January 2012, following the very first issue of this journal devoted to plant proteomics in May 2011. To disseminate organizational activities to the scientific community, INPPO has launched a biannual (in January and July) newsletter entitled 'INPPO Express: News & Views' with the first issue published in January 2012. INPPO is also planning to have several activities in 2012, including programs within the Education Outreach committee in different countries, and the development of research ideas and proposals with priority on crop and horticultural plants, while keeping tight interactions with proteomics programs on model plants such as Arabidopsis thaliana, rice, and Medicago truncatula. Altogether, the INPPO progress and upcoming activities are because of immense support, dedication, and hard work of all members of the INPPO community, and also due to the wide encouragement and support from the communities (scientific and non-scientific).

  • 9. Aguilo, Francesca
    et al.
    Avagyan, Serine
    Labar, Amy
    Sevilla, Ana
    Lee, Dung-Fang
    Kumar, Parameet
    Lemischka, Ihor R
    Zhou, Betty Y
    Snoeck, Hans-Willem
    Prdm16 is a physiologic regulator of hematopoietic stem cells.2011Inngår i: Blood, ISSN 0006-4971, E-ISSN 1528-0020, Vol. 117, nr 19Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fetal liver and adult bone marrow hematopoietic stem cells (HSCs) renew or differentiate into committed progenitors to generate all blood cells. PRDM16 is involved in human leukemic translocations and is expressed highly in some karyotypically normal acute myeloblastic leukemias. As many genes involved in leukemogenic fusions play a role in normal hematopoiesis, we analyzed the role of Prdm16 in the biology of HSCs using Prdm16-deficient mice. We show here that, within the hematopoietic system, Prdm16 is expressed very selectively in the earliest stem and progenitor compartments, and, consistent with this expression pattern, is critical for the establishment and maintenance of the HSC pool during development and after transplantation. Prdm16 deletion enhances apoptosis and cycling of HSCs. Expression analysis revealed that Prdm16 regulates a remarkable number of genes that, based on knockout models, both enhance and suppress HSC function, and affect quiescence, cell cycling, renewal, differentiation, and apoptosis to various extents. These data suggest that Prdm16 may be a critical node in a network that contains negative and positive feedback loops and integrates HSC renewal, quiescence, apoptosis, and differentiation.

  • 10.
    Aguilo, Francesca
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi. Departments of Structural and Chemical Biology, Genetics and Genomic Sciences and Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
    Di Cecilia, Serena
    Walsh, Martin J
    Long Non-coding RNA ANRIL and Polycomb in Human Cancers and Cardiovascular Disease2016Inngår i: Long non-coding RNAs in human disease, Springer, 2016, Vol. 394, s. 29-39Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    The long non-coding RNA CDKN2B-AS1, commonly referred to as the Antisense Non-coding RNA in the INK4 Locus (ANRIL), is a 3.8-kb-long RNA transcribed from the short arm of human chromosome 9 on p21.3 that overlaps a critical region encompassing three major tumor suppressor loci juxtaposed to the INK4b-ARF-INK4a gene cluster and the methyl-thioadenosine phosphorylase (MTAP) gene. Genome-wide association studies have identified this region with a remarkable and growing number of disease-associated DNA alterations and single nucleotide polymorphisms, which corresponds to increased susceptibility to human disease. Recent attention has been devoted on whether these alterations in the ANRIL sequence affect its expression levels and/or its splicing transcript variation, and in consequence, global cellular homeostasis. Moreover, recent evidence postulates that ANRIL not only can regulate their immediate genomic neighbors in cis, but also has the capacity to regulate additional loci in trans. This action would further increase the complexity for mechanisms imposed through ANRIL and furthering the scope of this lncRNA in disease pathogenesis. In this chapter, we summarize the most recent findings on the investigation of ANRIL and provide a perspective on the biological and clinical significance of ANRIL as a putative biomarker, specifically, its potential role in directing cellular fates leading to cancer and cardiovascular disease.

  • 11.
    Aguilo, Francesca
    et al.
    Icahn School of Medicine at Mount Sinai, New York, NY, USA.
    Li, SiDe
    Balasubramaniyan, Natarajan
    Sancho, Ana
    Benko, Sabina
    Zhang, Fan
    Vashisht, Ajay
    Rengasamy, Madhumitha
    Andino, Blanca
    Chen, Chih-hung
    Zhou, Felix
    Qian, Chengmin
    Zhou, Ming-Ming
    Wohlschlegel, James A
    Zhang, Weijia
    Suchy, Frederick J
    Walsh, Martin J
    Deposition of 5-Methylcytosine on Enhancer RNAs Enables the Coactivator Function of PGC-1α2016Inngår i: Cell Reports, E-ISSN 2211-1247, Vol. 14, nr 3, s. 479-492Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α) is a transcriptional co-activator that plays a central role in adapted metabolic responses. PGC-1α is dynamically methylated and unmethylated at the residue K779 by the methyltransferase SET7/9 and the Lysine Specific Demethylase 1A (LSD1), respectively. Interactions of methylated PGC-1α[K779me] with the Spt-Ada-Gcn5-acetyltransferase (SAGA) complex, the Mediator members MED1 and MED17, and the NOP2/Sun RNA methytransferase 7 (NSUN7) reinforce transcription, and are concomitant with the m(5)C mark on enhancer RNAs (eRNAs). Consistently, loss of Set7/9 and NSun7 in liver cell model systems resulted in depletion of the PGC-1α target genes Pfkl, Sirt5, Idh3b, and Hmox2, which was accompanied by a decrease in the eRNAs levels associated with these loci. Enrichment of m(5)C within eRNA species coincides with metabolic stress of fasting in vivo. Collectively, these findings illustrate the complex epigenetic circuitry imposed by PGC-1α at the eRNA level to fine-tune energy metabolism.

  • 12.
    Aguilo, Francesca
    et al.
    Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
    Zakirova, Zuchra
    Nolan, Katie
    Wagner, Ryan
    Sharma, Rajal
    Hogan, Megan
    Wei, Chengguo
    Sun, Yifei
    Walsh, Martin J.
    Kelley, Kevin
    Zhang, Weijia
    Ozelius, Laurie J.
    Gonzalez-Alegre, Pedro
    Zwaka, Thomas P.
    Ehrlich, Michelle E.
    THAP1: role in mouse embryonic stem cell survival and differentiation2017Inngår i: Stem Cell Reports, ISSN 2213-6711, Vol. 9, nr 1, s. 92-107Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    THAP1 (THAP [Thanatos-associated protein] domain-containing, apoptosis-associated protein 1) is a ubiquitously expressed member of a family of transcription factors with highly conserved DNA-binding and protein-interacting regions. Mutations in THAP1 cause dystonia, DYT6, a neurologic movement disorder. THAP1 downstream targets and the mechanism via which it causes dystonia are largely unknown. Here, we show that wild-type THAP1 regulates embryonic stem cell (ESC) potential, survival, and proliferation. Our findings identify THAP1 as an essential factor underlying mouse ESC survival and to some extent, differentiation, particularly neuroectodermal. Loss of THAP1 or replacement with a disease-causing mutation results in an enhanced rate of cell death, prolongs Nanog, Prdm14, and/or Rex1 expression upon differentiation, and results in failure to upregulate ectodermal genes. ChIP-Seq reveals that these activities are likely due in part to indirect regulation of gene expression.

    Fulltekst (pdf)
    fulltext
  • 13. Aguilo, Francesca
    et al.
    Zhang, Fan
    Sancho, Ana
    Fidalgo, Miguel
    Di Cecilia, Serena
    Vashisht, Ajay
    Lee, Dung-Fang
    Chen, Chih-Hung
    Rengasamy, Madhumitha
    Andino, Blanca
    Jahouh, Farid
    Roman, Angel
    Krig, Sheryl R
    Wang, Rong
    Zhang, Weijia
    Wohlschlegel, James A
    Wang, Jianlong
    Walsh, Martin J
    Coordination of m(6)A mRNA Methylation and Gene Transcription by ZFP217 Regulates Pluripotency and Reprogramming.2015Inngår i: Cell Stem Cell, ISSN 1934-5909, E-ISSN 1875-9777, Vol. 17, nr 6, s. 689-704Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Epigenetic and epitranscriptomic networks have important functions in maintaining the pluripotency of embryonic stem cells (ESCs) and somatic cell reprogramming. However, the mechanisms integrating the actions of these distinct networks are only partially understood. Here we show that the chromatin-associated zinc finger protein 217 (ZFP217) coordinates epigenetic and epitranscriptomic regulation. ZFP217 interacts with several epigenetic regulators, activates the transcription of key pluripotency genes, and modulates N6-methyladenosine (m(6)A) deposition on their transcripts by sequestering the enzyme m(6)A methyltransferase-like 3 (METTL3). Consistently, Zfp217 depletion compromises ESC self-renewal and somatic cell reprogramming, globally increases m(6)A RNA levels, and enhances m(6)A modification of the Nanog, Sox2, Klf4, and c-Myc mRNAs, promoting their degradation. ZFP217 binds its own target gene mRNAs, which are also METTL3 associated, and is enriched at promoters of m(6)A-modified transcripts. Collectively, these findings shed light on how a transcription factor can tightly couple gene transcription to m(6)A RNA modification to ensure ESC identity.

  • 14. Aguilo, Francesca
    et al.
    Zhou, Ming-Ming
    Walsh, Martin J
    Long noncoding RNA, polycomb, and the ghosts haunting INK4b-ARF-INK4a expression.2011Inngår i: Cancer Research, ISSN 0008-5472, E-ISSN 1538-7445, Vol. 71, nr 16Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Polycomb group proteins (PcG) function as transcriptional repressors of gene expression. The important role of PcG in mediating repression of the INK4b-ARF-INK4a locus, by directly binding to the long noncoding RNA (lncRNA) transcript antisense noncoding RNA in the INK4 locus (ANRIL), was recently shown. INK4b-ARF-INK4a encodes 3 tumor-suppressor proteins, p15(INK4b), p14(ARF), and p16(INK4a), and its transcription is a key requirement for replicative or oncogene-induced senescence and constitutes an important barrier for tumor growth. ANRIL gene is transcribed in the antisense orientation of the INK4b-ARF-INK4a gene cluster, and different single-nucleotide polymorphisms are associated with increased susceptibility to several diseases. Although lncRNA-mediated regulation of INK4b-ARF-INK4a gene is not restricted to ANRIL, both polycomb repressive complex-1 (PRC1) and -2 (PRC2) interact with ANRIL to form heterochromatin surrounding the INK4b-ARF-INK4a locus, leading to its repression. This mechanism would provide an increased advantage for bypassing senescence, sustaining the requirements for the proliferation of stem and/or progenitor cell populations or inappropriately leading to oncogenesis through the aberrant saturation of the INK4b-ARF-INK4a locus by PcG complexes. In this review, we summarize recent findings on the underlying epigenetic mechanisms that link PcG function with ANRIL, which impose gene silencing to control cellular homeostasis as well as cancer development.

  • 15. Aguiló, Francesca
    et al.
    Camarero, Nuria
    Relat, Joana
    Marrero, Pedro F
    Haro, Diego
    Transcriptional regulation of the human acetoacetyl-CoA synthetase gene by PPARgamma.2010Inngår i: Biochemical Journal, ISSN 0264-6021, E-ISSN 1470-8728, Vol. 427, nr 2Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the cytosol of lipogenic tissue, ketone bodies are activated by AACS (acetoacetyl-CoA synthetase) and incorporated into cholesterol and fatty acids. AACS gene expression is particularly abundant in white adipose tissue, as it is induced during adipocyte differentiation. In order to elucidate the mechanism controlling the gene expression of human AACS and to clarify its physiological role, we isolated the human promoter, characterized the elements required to initiate transcription and analysed the expression of the gene in response to PPARgamma (peroxisome-proliferator-activated receptor gamma), an inducer of adipogenesis. We show that the human AACS promoter is a PPARgamma target gene and that this nuclear receptor is recruited to the AACS promoter by direct interaction with Sp1 (stimulating protein-1).

  • 16.
    Ahlgren, Ulf
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Gotthardt, Martin
    Department of Nuclear Medicine, Nijmegen, Netherlands.
    Approaches for imaging islets2010Inngår i: Advances in Experimental Medicine and Biology, ISSN 0065-2598, E-ISSN 2214-8019, Vol. 654, s. 39-57Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The establishment of improved technologies for imaging of the pancreas is a key element in addressing several aspects of diabetes pathogenesis. In this respect, the development of a protocol that allows for non-invasive scoring of human islets, or islet beta-cells, is of particular importance. The development of such a technology would have profound impact on both clinical and experimental medicine, ranging from early diagnosis of diabetes to the evaluation of therapeutic regimes. Another important task is the development of modalities for high-resolution imaging of experimental animal models for diabetes. Rodent models for diabetes research have for decades been instrumental to the diabetes research community. The ability to image, and to accurately quantify, key players of diabetogenic processes with molecular specificity will be of great importance for elucidating mechanistic aspects of the disease. This chapter aims to overview current progress within these research areas.

  • 17.
    Ahmed, Heba A.
    et al.
    Department of Biological and Geological Sciences, University of Alexandria, Egypt.
    Ibrahim, Lidia L.
    Department of Biological and Geological Sciences, University of Alexandria, Egypt.
    El Mekkawy, Desouki A.
    Department of Zoology, University of Alexandria, Egypt.
    El Wakil, Abeer
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten). Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet). Department of Biological and Geological Sciences, University of Alexandria, Egypt.
    Expression pattern of the orphan nuclear receptor, nurr1, in the developing mouse forelimb and its relationship to limb skeletogenesis and osteogenesis2015Inngår i: OnLine Journal of Biological Sciences, ISSN 1608-4217, Vol. 15, nr 3, s. 162-169Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The NR4A orphan nuclear receptor, Nurr1, has been shown to regulate the expression of osteoblastic genes and osteoblastic differentiation. However, the expression profile of Nurr1 in the developing mouse forelimb and its relationship to skeletogenesis has not, to the best of our knowledge, been previously analyzed. In this study, the relationship between Nurr1 expression pattern, skeletogenesis and osteogenesis in the developing mouse forelimb was investigated. The expression level of Nurr1 during development was also quantified by real time-polymerase chain reaction. Our results revealed that Nurr1 is expressed in the mesenchyme cells that will form the skeleton. Nurr1 is aabundantly expressed in the primary ossification centers of the forelimb skeletal elements and its expression level is gradually increased during limb development, particularly, at the onset of ossification. Collectively, these data suggested that Nurr1 plays an important role in skeletogenesis and patterning of the developing mouse forelimb.

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  • 18.
    Akhunzianov, Almaz A.
    et al.
    Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russian Federation.
    Nesterova, Alfiya I.
    Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russian Federation; Republican Clinical Oncology Dispensary Named after Prof. M.Z. Sigal, Kazan, Russian Federation.
    Wanrooij, Sjoerd
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Filina, Yulia V.
    Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russian Federation.
    Rizvanov, Albert A.
    Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russian Federation.
    Miftakhova, Regina R.
    Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russian Federation.
    Unravelling the Therapeutic Potential of Antibiotics in Hypoxia in a Breast Cancer MCF-7 Cell Line Model2023Inngår i: International Journal of Molecular Sciences, ISSN 1661-6596, E-ISSN 1422-0067, Vol. 24, nr 14, artikkel-id 11540Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Antibiotics inhibit breast cancer stem cells (CSCs) by suppressing mitochondrial biogenesis. However, the effectiveness of antibiotics in clinical settings is inconsistent. This inconsistency raises the question of whether the tumor microenvironment, particularly hypoxia, plays a role in the response to antibiotics. Therefore, the goal of this study was to evaluate the effectiveness of five commonly used antibiotics for inhibiting CSCs under hypoxia using an MCF-7 cell line model. We assessed the number of CSCs through the mammosphere formation assay and aldehyde dehydrogenase (ALDH)-bright cell count. Additionally, we examined the impact of antibiotics on the mitochondrial stress response and membrane potential. Furthermore, we analyzed the levels of proteins associated with therapeutic resistance. There was no significant difference in the number of CSCs between cells cultured under normoxic and hypoxic conditions. However, hypoxia did affect the rate of CSC inhibition by antibiotics. Specifically, azithromycin was unable to inhibit sphere formation in hypoxia. Erythromycin and doxycycline did not reduce the ratio of ALDH-bright cells, despite decreasing the number of mammospheres. Furthermore, treatment with chloramphenicol, doxycycline, and tetracycline led to the overexpression of the breast cancer resistance protein. Our findings suggest that hypoxia may weaken the inhibitory effects of antibiotics on the breast cancer model.

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  • 19. Akkaya, Munir
    et al.
    Bansal, Abhisheka
    Sheehan, Patrick W.
    Pena, Mirna
    Cimperman, Clare K.
    Qi, Chen Feng
    Yazew, Takele
    Otto, Thomas D.
    Billker, Oliver
    Umeå universitet, Medicinska fakulteten, Molekylär Infektionsmedicin, Sverige (MIMS). Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet).
    Miller, Louis H.
    Pierce, Susan K.
    Testing the impact of a single nucleotide polymorphism in a Plasmodium berghei ApiAP2 transcription factor on experimental cerebral malaria in mice2020Inngår i: Scientific Reports, E-ISSN 2045-2322, Vol. 10, nr 1, artikkel-id 13630Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cerebral malaria (CM) is the deadliest form of severe Plasmodium infections. Currently, we have limited understanding of the mechanisms by which Plasmodium parasites induce CM. The mouse model of CM, experimental CM (ECM), induced by infection with the rodent parasite, Plasmodium berghei ANKA (PbANKA) has been extensively used to study the pathophysiology of CM. Recent genomic analyses revealed that the coding regions of PbANKA and the closely related Plasmodium berghei NK65 (PbNK65), that does not cause ECM, differ in only 21 single nucleotide polymorphysims (SNPs). Thus, the SNP-containing genes might contribute to the pathogenesis of ECM. Although the majority of these SNPs are located in genes of unknown function, one SNP is located in the DNA binding site of a member of the Plasmodium ApiAP2 transcription factor family, that we recently showed functions as a virulence factor alternating the host's immune response to the parasite. Here, we investigated the impact of this SNP on the development of ECM. Our results using CRISPR-Cas9 engineered parasites indicate that despite its immune modulatory function, the SNP is neither necessary nor sufficient to induce ECM and thus cannot account for parasite strain-specific differences in ECM phenotypes.

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  • 20. Akkaya, Munir
    et al.
    Bansal, Abhisheka
    Sheehan, Patrick W.
    Pena, Mirna
    Molina-Cruz, Alvaro
    Orchard, Lindsey M.
    Cimperman, Clare K.
    Qi, Chen-Feng
    Ross, Philipp
    Yazew, Takele
    Sturdevant, Daniel
    Anzick, Sarah L.
    Thiruvengadam, Girija
    Otto, Thomas Dan
    Billker, Oliver
    Umeå universitet, Medicinska fakulteten, Molekylär Infektionsmedicin, Sverige (MIMS). Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet).
    Llinas, Manuel
    Miller, Louis H.
    Pierce, Susan K.
    A single-nucleotide polymorphism in a Plasmodium berghei ApiAP2 transcription factor alters the development of host immunity2020Inngår i: Science Advances, E-ISSN 2375-2548, Vol. 6, nr 6, artikkel-id eaaw6957Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The acquisition of malaria immunity is both remarkably slow and unpredictable. At present, we know little about the malaria parasite genes that influence the host's ability to mount a protective immune response. Here, we show that a single-nucleotide polymorphism (SNP) resulting in a single amino acid change (S to F) in an ApiAP2 transcription factor in the rodent malaria parasite Plasmodium berghei (Pb) NK65 allowed infected mice to mount a T helper cell 1 (T(H)1)-type immune response that controlled subsequent infections. As compared to PbNK65(S), PbNK65(F) parasites differentially expressed 46 genes, most of which are predicted to play roles in immune evasion. PbNK65(F) infections resulted in an early interferon-gamma response and a later expansion of germinal centers, resulting in high levels of infected red blood cell-specific T(H)1-type immunoglobulin G2b (IgG2b) and IgG2c antibodies. Thus, the Pb ApiAP2 transcription factor functions as a critical parasite virulence factor in malaria infections.

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  • 21. Akram, Neelam
    et al.
    Palovaara, Joakim
    Forsberg, Jeremy
    Lindh, Markus V.
    Milton, Debra L.
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Luo, Haiwei
    Gonzalez, Jose M.
    Pinhassi, Jarone
    Regulation of proteorhodopsin gene expression by nutrient limitation in the marine bacterium Vibrio sp AND42013Inngår i: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 15, nr 5, s. 1400-1415Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Proteorhodopsin (PR), a ubiquitous membrane photoprotein in marine environments, acts as a light-driven proton pump and can provide energy for bacterial cellular metabolism. However, knowledge of factors that regulate PR gene expression in different bacteria remains strongly limited. Here, experiments with Vibrio sp. AND4 showed that PR phototrophy promoted survival only in cells from stationary phase and not in actively growing cells. PR gene expression was tightly regulated, with very low values in exponential phase, a pronounced peak at the exponential/stationary phase intersection, and a marked decline in stationary phase. Thus, PR gene expression at the entry into stationary phase preceded, and could therefore largely explain, the stationary phase light-induced survival response in AND4. Further experiments revealed nutrient limitation, not light exposure, regulated this differential PR expression. Screening of available marine vibrios showed that the PR gene, and thus the potential for PR phototrophy, is found in at least three different clusters in the genus Vibrio. In an ecological context, our findings suggest that some PR-containing bacteria adapted to the exploitation of nutrient-rich micro-environments rely on a phase of relatively slowly declining resources to mount a cellular response preparing them for adverse conditions dispersed in the water column.

  • 22.
    Alakpa, Enateri V.
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Jayawarna, Vineetha
    Burgess, Karl E. V.
    West, Christopher C.
    Peault, Bruno
    Ulijn, Rein V.
    Dalby, Matthew J.
    Improving cartilage phenotype from differentiated pericytes in tunable peptide hydrogels2017Inngår i: Scientific Reports, E-ISSN 2045-2322, Vol. 7, artikkel-id 6895Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Differentiation of stem cells to chondrocytes in vitro usually results in a heterogeneous phenotype. This is evident in the often detected over expression of type X collagen which, in hyaline cartilage structure is not characteristic of the mid-zone but of the deep-zone ossifying tissue. Methods to better match cartilage developed in vitro to characteristic in vivo features are therefore highly desirable in regenerative medicine. This study compares phenotype characteristics between pericytes, obtained from human adipose tissue, differentiated using diphenylalanine/serine (F2/S) peptide hydrogels with the more widely used chemical induced method for chondrogenesis. Significantly higher levels of type II collagen were noted when pericytes undergo chondrogenesis in the hydrogel in the absence of induction media. There is also a balanced expression of collagen relative to aggrecan production, a feature which was biased toward collagen production when cells were cultured with induction media. Lastly, metabolic profiles of each system show considerable overlap between both differentiation methods but subtle differences which potentially give rise to their resultant phenotype can be ascertained. The study highlights how material and chemical alterations in the cellular microenvironment have wide ranging effects on resultant tissue type.

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  • 23.
    Alam, Athar
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi. Umeå universitet, Medicinska fakulteten, Molekylär Infektionsmedicin, Sverige (MIMS).
    Bröms, Jeanette E
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi. Umeå universitet, Medicinska fakulteten, Molekylär Infektionsmedicin, Sverige (MIMS).
    Kumar, Rajender
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi. Umeå universitet, Medicinska fakulteten, Molekylär Infektionsmedicin, Sverige (MIMS).
    Sjöstedt, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi. Umeå universitet, Medicinska fakulteten, Molekylär Infektionsmedicin, Sverige (MIMS).
    The Role of ClpB in Bacterial Stress Responses and Virulence2021Inngår i: Frontiers in Molecular Biosciences, E-ISSN 2296-889X, Vol. 8, artikkel-id 668910Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Bacterial survival within a mammalian host is contingent upon sensing environmental perturbations and initiating an appropriate counter-response. To achieve this, sophisticated molecular machineries are used, where bacterial chaperone systems play key roles. The chaperones are a prerequisite for bacterial survival during normal physiological conditions as well as under stressful situations, e.g., infection or inflammation. Specific stress factors include, but are not limited to, high temperature, osmolarity, pH, reactive oxidative species, or bactericidal molecules. ClpB, a member of class 1 AAA+ proteins, is a key chaperone that via its disaggregase activity plays a crucial role for bacterial survival under various forms of stress, in particular heat shock. Recently, it has been reported that ClpB also regulates secretion of bacterial effector molecules related to type VI secretion systems. In this review, the roles of ClpB in stress responses and the mechanisms by which it promotes survival of pathogenic bacteria are discussed.

    Fulltekst (pdf)
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  • 24. Alavi, Y.
    et al.
    Arai, M.
    Mendoza, J.
    Tufet-Bayona, M.
    Sinha, R.
    Fowler, K.
    Billker, Oliver
    Department of Biological Sciences, Imperial College London, London SW7 2AZ, UK.
    Franke-Fayard, B
    Janse, C J
    Waters, A
    Sinden, R E
    The dynamics of interactions between Plasmodium and the mosquito: a study of the infectivity of Plasmodium berghei and Plasmodium gallinaceum, and their transmission by Anopheles stephensi, Anopheles gambiae and Aedes aegypti2003Inngår i: International Journal of Parasitology, ISSN 0020-7519, E-ISSN 1879-0135, Vol. 33, nr 9, s. 933-943Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Knowledge of parasite–mosquito interactions is essential to develop strategies that will reduce malaria transmission through the mosquito vector. In this study we investigated the development of two model malaria parasites, Plasmodium berghei and Plasmodium gallinaceum, in three mosquito species Anopheles stephensi, Anopheles gambiae and Aedes aegypti. New methods to study gamete production in vivo in combination with GFP-expressing ookinetes were employed to measure the large losses incurred by the parasites during infection of mosquitoes. All three mosquito species transmitted P. gallinaceumP. berghei was only transmitted by Anopheles spp. Plasmodium gallinaceum initiates gamete production with high efficiency equally in the three mosquito species. By contrast P. berghei is less efficiently activated to produce gametes, and in Ae. aegypti microgamete formation is almost totally suppressed. In all parasite/vector combinations ookinete development is inefficient, 500–100,000-fold losses were encountered. Losses during ookinete-to-oocyst transformation range from fivefold in compatible vector parasite combinations (P. berghei/An. stephensi), through >100-fold in poor vector/parasite combinations (P. gallinaceum/An. stephensi), to complete blockade (>1,500 fold) in others (P. berghei/Ae. aegypti). Plasmodium berghei ookinetes survive poorly in the bloodmeal of Ae. aegypti and are unable to invade the midgut epithelium. Cultured mature ookinetes of P. berghei injected directly into the mosquito haemocoele produced salivary gland sporozoites in An. stephensi, but not in Ae. aegypti, suggesting that further species-specific incompatibilities occur downstream of the midgut epithelium in Ae. aegypti. These results show that in these parasite–mosquito combinations the susceptibility to malarial infection is regulated at multiple steps during the development of the parasites. Understanding these at the molecular level may contribute to the development of rational strategies to reduce the vector competence of malarial vectors.

  • 25.
    Alenius, Mattias
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet).
    Bohm, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet). Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Differential function of RNCAM isoforms in precise target selection of olfactory sensory neurons2003Inngår i: Development, ISSN 0950-1991, E-ISSN 1477-9129, Vol. 130, nr 5, s. 917-927Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Olfactory sensory neurons (OSNs) are individually specified to express one odorant receptor (OR) gene among similar to1000 different and project with precision to topographically defined convergence sites, the glomeruli, in the olfactory bulb. Although ORs partially determine the location of convergence sites, the mechanism ensuring that axons with different OR identities do not co-converge is unknown. RNCAM (OCAM, NCAM2) is assumed to regulate a broad zonal segregation of projections by virtue of being a homophilic cell adhesion molecule that is selectively expressed on axons terminating in a defined olfactory bulb region. We have identified NADPH diaphorase activity as being an independent marker for RNCAM-negative axons. Analyses of transgenic mice that ectopically express RNCAM in NADPH diaphorasepositive OSNs show that the postulated function of RNCAM in mediating zone-specific segregation of axons is unlikely. Instead, analyses of one OR-specific OSN subpopulation (P2) reveal that elevated RNCAM levels result in an increased number of P2 axons that incorrectly co-converge with axons of other OR identities. Both Gpianchored and transmembrane-bound RNCAM isoforms are localized on axons in the nerve layer, while the transmembrane-bound RNCAM is the predominant isoform on axon terminals within glomeruli. Overexpressing transmembrane-bound RNCAM results in co-convergence events close to the correct target glomeruli. By contrast, overexpression of Gpi-anchored RNCAM results in axons that can bypass the correct target before co-converging on glomeruli located at a distance. The phenotype specific for Gpi-anchored RNCAM is suppressed in mice overexpressing both isoforms, which suggests that two distinct RNCAM isoform-dependent activities influence segregation of OR-defined axon subclasses.

  • 26.
    Al-Furoukh, Natalie
    et al.
    Max-Planck-Institute for Heart and Lung Research, Ludwigstrasse 43, 61231 Bad Nauheim, Germany.
    Goffart, Steffi
    Szibor, Marten
    Wanrooij, Sjoerd
    Braun, Thomas
    Binding to G-quadruplex RNA activates the mitochondrial GTPase NOA1.2013Inngår i: Biochimica et Biophysica Acta, ISSN 0006-3002, E-ISSN 1878-2434, Vol. 1833, nr 12Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    NOA1 is an evolutionary conserved, nuclear encoded GTPase essential for mitochondrial function and cellular survival. The function of NOA1 for assembly of mitochondrial ribosomes and regulation of OXPHOS activity depends on its GTPase activity, but so far no ligands have been identified that regulate the GTPase activity of NOA1. To identify nucleic acids that bind to the RNA-binding domain of NOA1 we employed SELEX (Systemic Evolution of Ligands by EXponential Enrichment) using recombinant mouse wildtype NOA1 and the GTPase mutant NOA1-K353R. We found that NOA1 binds specifically to oligonucleotides that fold into guanine tetrads (G-quadruplexes). Binding of G-quadruplex oligonucleotides stimulated the GTPase activity of NOA1 suggesting a regulatory link between G-quadruplex containing RNAs, NOA1 function and assembly of mitochondrial ribosomes.

  • 27.
    Al-Furoukh, Natalie
    et al.
    Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany.
    Kardon, Julia R
    Krüger, Marcus
    Szibor, Marten
    Baker, Tania A
    Braun, Thomas
    NOA1, a novel ClpXP substrate, takes an unexpected nuclear detour prior to mitochondrial import.2014Inngår i: PLOS ONE, E-ISSN 1932-6203, Vol. 9, nr 7Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The mitochondrial matrix GTPase NOA1 is a nuclear encoded protein, essential for mitochondrial protein synthesis, oxidative phosphorylation and ATP production. Here, we demonstrate that newly translated NOA1 protein is imported into the nucleus, where it localizes to the nucleolus and interacts with UBF1 before nuclear export and import into mitochondria. Mutation of the nuclear localization signal (NLS) prevented both nuclear and mitochondrial import while deletion of the N-terminal mitochondrial targeting sequence (MTS) or the C-terminal RNA binding domain of NOA1 impaired mitochondrial import. Absence of the MTS resulted in accumulation of NOA1 in the nucleus and increased caspase-dependent apoptosis. We also found that export of NOA1 from the nucleus requires a leptomycin-B sensitive, Crm1-dependent nuclear export signal (NES). Finally, we show that NOA1 is a new substrate of the mitochondrial matrix protease complex ClpXP. Our results uncovered an unexpected, mandatory detour of NOA1 through the nucleolus before uptake into mitochondria. We propose that nucleo-mitochondrial translocation of proteins is more widespread than previously anticipated providing additional means to control protein bioavailability as well as cellular communication between both compartments.

  • 28.
    Ali, Haytham
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi. Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi. Department of Pathology, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt.
    Ohlsson, Lina
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Lindmark, Gudrun
    Institution of Clinical Sciences, Lund University, SE, Lund, Sweden.
    Hammarström, Marie-Louise
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Hammarström, Sten
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Sitohy, Basel
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi. Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    The myeloid cell biomarker EMR1 is ectopically expressed in colon cancer2021Inngår i: Tumor Biology, ISSN 1010-4283, E-ISSN 1423-0380, Vol. 43, nr 1, s. 209-223Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE: The microenvironment of colon cancer (CC) is heterogeneous including cells of myeloid lineage affecting tumor growth and metastasis. Two functional subtypes of myeloid cells have been identified; one (M1) is tumor-inhibitory and the other one (M2) is tumor-promoting. Whether the three myeloid markers EMR1, CD206 and CD86 are expressed only in the infiltrating myeloid cells or also in the tumor cells was investigated.

    METHODS: Expression of the myeloid markers was investigated in CC at the mRNA and protein levels in primary tumors and lymph nodes. mRNA expression was also determined in 5 CC cell lines. Protein expression was investigated by two-color immunofluorescence and consecutive-sections-immune-staining combined with morphometry using specific antibodies for the myeloid cell markers and the epithelial cell markers CEACAM5 and EpCAM.

    RESULTS: EMR1 and CD86, but not CD206, mRNA levels were significantly higher in CC primary tumors compared to apparently normal colon tissue (P <  0.0001). EMR1 mRNA levels were significantly higher in both hematoxylin-eosin positive (H&E(+)) and H&E(-) lymph nodes of CC patients compared to control nodes (P = 0.03 and P = 0.01, respectively). EMR1 and CD206 mRNAs were expressed in 4/5 and 5/5 CC cell lines, respectively, while CD86 mRNA was not expressed. Immuno-morphometry revealed that about 20% of the tumor cells expressed EMR1 and CD206. Positive cells were tumor cells as revealed by anti-CEACAM5 and anti-EpCAM staining. The number of EMR1, CD206 and CD86 positive cells were significantly increased in CC primary tumors compared to normal colon tissue (P <  0.0001). However, CD206 was also expressed in normal colonocytes. Only EMR1 showed significantly increased numbers of positive tumor cells in H&E(+) nodes compared to H&E(-) nodes (P = 0.001). EMR1 expression in CC tumor cells correlated with CXCL17 expressing tumor cells.

    CONCLUSION: EMR1, like the chemokine CXCL17, is ectopically expressed in colon cancer possibly in the same cancer cells.

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  • 29.
    ALi, Kassem
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Henning, Petra
    Lundberg, Pernilla
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Movérare-Skrtic, Sofia
    Souza, Pedro
    Lindholm, Catharina
    Lerner, Ulf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Toll-like receptor induced inflammation causes local bone formationManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    It is well established that inflammatory processes in the vicinity of bone often induce osteoclast formation and bone resorption. Effects on bone formation by inflammatory processes are much less studied and available information is partly contradictory. In the present study, we have assessed the effect on bone formation by locally induced inflammation. LPS from Porphyromonas gingivalis and Pam2, used as Toll-like receptor (TLR) 2 agonists, and flagellin from Salmonella typhimurium, used as TLR5 agonist, were injected subcutaneously on the top of mouse skull bones. After 1-5 days, the calvarial bones were dissected and processed either for histological or gene expression analyses. Femur was dissected for analysis with microCT and histology. At day 5, all three agonists induced bone formation on periosteal and endosteal sites, as well as in the bone marrow compartment of the calvaria. This response was seen both in close vicinity to, but also apart from, osteoclasts and bone resorption cavities. In areas close to new bone formation, abundance of proliferating cells was observed as assessed by Ki67 labelling. Gene expression analyses showed that Pam2 treatment resulted in increased mRNA expression at day 5 of genes encoding bone matrix proteins, alkaline phosphatase and of the osteoblastic transcription factors Runx2 and osterix. Robust Runx2 protein was observed in osteoblasts in areas with new bone formation. Pam2 treatment also increased the mRNA expression of cytokines in the IL-6 family, as well as of their cognate receptors and common signaling transduction subunit gp130. At day 5, the mRNA expression of Bmp2, Bmp4, Tgfb1, Lrp5, Lrp6 and Wnt7b was increased, whereas Sost was decreased. In the femur, excessive osteoclast formation and trabecular bone loss was found at day 5, but new bone formation was not observed. In conclusion, these data show that inflammatory processes not only induce osteoclastogenesis but also have the capacity to activate osteoblasts and stimulate new bone formation distinct from bone remodeling sites. Stimulation of inflammation- induced new bone formation may be due to enhanced gp130 signaling. Osteoblast activation in the inflammatory processes may also involve the BMP and WNT signaling systems.

  • 30. Ali, Yusuf
    et al.
    Diez, Juan
    Selander, Lars
    Zheng, Xiaofeng
    Edlund, Helena
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM). Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, FL, USA.
    Berggren, Per-Olof
    The anterior chamber of the eye is a transplantation site that supports and enables visualisation of beta cell development in mice2016Inngår i: Diabetologia, ISSN 0012-186X, E-ISSN 1432-0428, Vol. 59, nr 5, s. 1007-1011Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In vivo imaging of the developing pancreas is challenging due to the inaccessibility of the tissue. To circumvent this, on embryonic day 10.5 (E10.5) we transplanted a mouse developing pancreatic bud into the anterior chamber of the eye (ACE) to determine whether the eye is a useful transplant site to support pancreas development. We transplanted an E10.5 dorsal pancreatic bud into the ACE of a syngeneic recipient mouse. Using a mouse insulin promoter-green fluorescent protein (MIP-GFP) mouse as the tissue donor, we non-invasively imaged the pancreatic bud as it develops at single beta cell resolution across time. The transplanted pancreatic bud rapidly engrafts and vascularises when transplanted into the ACE. The pancreatic progenitor cells differentiate into exocrine and endocrine cells, including cells expressing insulin, glucagon and somatostatin. The morphology of the transplanted pancreatic bud resembles that of the native developing pancreas. Beta cells within the transplanted pancreatic bud respond to glucose in a manner similar to that of native fetal beta cells and superior to that of in vitro developed beta cells. Unlike in vitro grown pancreatic explants, pancreatic tissue developing in the ACE is vascularised, providing the developing pancreatic tissue with a milieu resembling the native situation. Altogether, we show that the ACE is able to support growth, differentiation and function of a developing pancreatic bud across time in vivo.

  • 31. Alkaitis, Matthew S.
    et al.
    Wang, Honghui
    Ikeda, Allison K.
    Rowley, Carol A.
    MacCormick, Ian J. C.
    Chertow, Jessica H.
    Billker, Oliver
    Wellcome Trust Sanger Institute, Hinxton, UK.
    Suffredini, Anthony F.
    Roberts, David J.
    Taylor, Terrie E.
    Seydel, Karl B.
    Ackerman, Hans C.
    Decreased Rate of Plasma Arginine Appearance in Murine Malaria May Explain Hypoargininemia in Children With Cerebral Malaria2016Inngår i: Journal of Infectious Diseases, ISSN 0022-1899, E-ISSN 1537-6613, Vol. 214, nr 12, s. 1840-1849Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND:  Plasmodium infection depletes arginine, the substrate for nitric oxide synthesis, and impairs endothelium-dependent vasodilation. Increased conversion of arginine to ornithine by parasites or host arginase is a proposed mechanism of arginine depletion.

    METHODS:  We used high-performance liquid chromatography to measure plasma arginine, ornithine, and citrulline levels in Malawian children with cerebral malaria and in mice infected with Plasmodium berghei ANKA with or without the arginase gene. Heavy isotope-labeled tracers measured by quadrupole time-of-flight liquid chromatography-mass spectrometry were used to quantify the in vivo rate of appearance and interconversion of plasma arginine, ornithine, and citrulline in infected mice.

    RESULTS:  Children with cerebral malaria and P. berghei-infected mice demonstrated depletion of plasma arginine, ornithine, and citrulline. Knock out of Plasmodium arginase did not alter arginine depletion in infected mice. Metabolic tracer analysis demonstrated that plasma arginase flux was unchanged by P. berghei infection. Instead, infected mice exhibited decreased rates of plasma arginine, ornithine, and citrulline appearance and decreased conversion of plasma citrulline to arginine. Notably, plasma arginine use by nitric oxide synthase was decreased in infected mice.

    CONCLUSIONS:  Simultaneous arginine and ornithine depletion in malaria parasite-infected children cannot be fully explained by plasma arginase activity. Our mouse model studies suggest that plasma arginine depletion is driven primarily by a decreased rate of appearance.

  • 32.
    Alkhori, Liza
    et al.
    Linköpings universitet, Avdelningen för cellbiologi.
    Öst, Anita
    Linköpings universitet, Avdelningen för cellbiologi.
    Alenius, Mattias
    Linköpings universitet, Avdelningen för cellbiologi.
    The corepressor Atrophin specifies odorant receptor expression in Drosophila2014Inngår i: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 28, nr 3, s. 1355-1364Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In both insects and vertebrates, each olfactory sensory neuron (OSN) expresses one odorant receptor (OR) from a large genomic repertoire. How a receptor is specified is a tantalizing question addressing fundamental aspects of cell differentiation. Here, we demonstrate that the corepressor Atrophin (Atro) segregates OR gene expression between OSN classes in Drosophila. We show that the knockdown of Atro result in either loss or gain of a broad set of ORs. Each OR phenotypic group correlated with one of two opposing Notch fates, Notch responding, Nba (N(on)), and nonresponding, Nab (N(off)) OSNs. Our data show that Atro segregates ORs expressed in the Nba OSN classes and helps establish the Nab fate during OSN development. Consistent with a role in recruiting histone deacetylates, immunohistochemistry revealed that Atro regulates global histone 3 acetylation (H3ac) in OSNs and requires Hdac3 to segregate OR gene expression. We further found that Nba OSN classes exhibit variable but higher H3ac levels than the Nab OSNs. Together, these data suggest that Atro determines the level of H3ac, which ensures correct OR gene expression within the Nba OSNs. We propose a mechanism by which a single corepressor can specify a large number of neuron classes.-Alkhori, L., Öst, A., Alenius, M. The corepressor Atrophin specifies odorant receptor expression in Drosophila.

  • 33.
    Amjad, Asma
    et al.
    Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, Italy.
    Hernandez-Clavijo, Andres
    Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, 34136 Trieste, Italy.
    Pifferi, Simone
    Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, Italy.
    Maurya, Devendra Kumar
    Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, Italy.
    Boccaccio, Anna
    Istituto di Biofisica, National Research Council, Genova, Italy.
    Franzot, Jessica
    Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, Italy.
    Rock, Jason
    Department of Anatomy, University of California, San Francisco, School of Medicine, San Francisco, USA.
    Menini, Anna
    Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, Italy.
    Conditional knockout of TMEM16A/anoctamin1 abolishes the calcium-activated chloride current in mouse vomeronasal sensory neurons2015Inngår i: The Journal of General Physiology, ISSN 0022-1295, E-ISSN 1540-7748, Vol. 145, nr 4, s. 285-301Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Pheromones are substances released from animals that, when detected by the vomeronasal organ of other individuals of the same species, affect their physiology and behavior. Pheromone binding to receptors on microvilli on the dendritic knobs of vomeronasal sensory neurons activates a second messenger cascade to produce an increase in intracellular Ca2+ concentration. Here, we used whole-cell and inside-out patch-clamp analysis to provide a functional characterization of currents activated by Ca2+ in isolated mouse vomeronasal sensory neurons in the absence of intracellular K+. In whole-cell recordings, the average current in 1.5 µM Ca2+ and symmetrical Cl− was −382 pA at −100 mV. Ion substitution experiments and partial blockade by commonly used Cl− channel blockers indicated that Ca2+ activates mainly anionic currents in these neurons. Recordings from inside-out patches from dendritic knobs of mouse vomeronasal sensory neurons confirmed the presence of Ca2+-activated Cl− channels in the knobs and/or microvilli. We compared the electrophysiological properties of the native currents with those mediated by heterologously expressed TMEM16A/anoctamin1 or TMEM16B/anoctamin2 Ca2+-activated Cl− channels, which are coexpressed in microvilli of mouse vomeronasal sensory neurons, and found a closer resemblance to those of TMEM16A. We used the Cre–loxP system to selectively knock out TMEM16A in cells expressing the olfactory marker protein, which is found in mature vomeronasal sensory neurons. Immunohistochemistry confirmed the specific ablation of TMEM16A in vomeronasal neurons. Ca2+-activated currents were abolished in vomeronasal sensory neurons of TMEM16A conditional knockout mice, demonstrating that TMEM16A is an essential component of Ca2+-activated Cl− currents in mouse vomeronasal sensory neurons.

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  • 34.
    Andersson, Christopher
    Umeå universitet, Medicinska fakulteten, Molekylär Infektionsmedicin, Sverige (MIMS). Umeå universitet, Medicinska fakulteten, Umeå Centre for Microbial Research (UCMR). Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Regulatory pathways and virulence inhibition in Listeria monocytogenes2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Listeria monocytogenes is a rod-shaped Gram positive bacterium. It generally exist ubiquitously in nature, where it lives as a saprophyte. Occasionally it however enters the food chain, from where it can be ingested by humans and cause gastro-intestinal distress. In immunocompetent individuals L. monocytogenes is generally cleared within a couple of weeks, but in immunocompromised patients it can progress to listeriosis, a potentially life-threatening infection in the central nervous system. If the infected individual is pregnant, the bacteria can cross the placental barrier and infect the fetus, possibly leading to spontaneous abortion.

    The infectivity of L. monocytogenes requires a certain set of genes, and the majority of them is dependent on the transcriptional regulator PrfA. The expression and activity of PrfA is controlled at several levels, and has traditionally been viewed to be active at 37 °C (virulence conditions) where it bind as a homodimer to a “PrfA-box” and induces the expression of the downstream gene.

    One of these genes is ActA, which enables intracellular movement by recruiting an actin polymerizing protein complex. When studying the effects of a blue light receptor we surprisingly found an effect of ActA at non-virulent conditions, where it is required for the bacteria to properly react to light exposure.

    To further study the PrfA regulon we tested deletion mutants of several PrfA-regulated virulence genes in chicken embryo infection studies. Based on these studies we could conclude that the chicken embryo model is a viable complement to traditional murine models, especially when investigating non-traditional internalin pathogenicity pathways. We have also studied the effects of small molecule virulence inhibitors that, by acting on PrfA, can inhibit L. monocytogenes infectivity in cell cultures with concentrations in the low micro-molar range.

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  • 35.
    Andersson, Elisabet
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    The evolutionary study of the immunoglobulin heavy chain genes of a bony fish, rainbow trout (Oncorhynchus mykiss)1995Doktoravhandling, med artikler (Annet vitenskapelig)
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    The evolutionary study of the immunoglobulin heavy chain genes of a bony fish, rainbow trout (Oncorhynchus mykiss)
  • 36.
    Andersson, Gustav
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi. Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Idrottsmedicin.
    Influences of paratendinous innervation and non-neuronal substance P in tendinopathy: studies on human tendon tissue and an experimental model of Achilles tendinopathy2010Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Pain of the musculoskeletal system is one of the most common reasons for people seeking medical attention, and is also one of the major factors that prevent patients from working. Chronic tendon pain, tendinopathy, affects millions of workers world-wide, and the Achilles tendon is an important structure often afflicted by this condition. The pathogenesis of tendinopathy is poorly understood, but it is thought to be of multifactoral aetiology. It is known that tendon pain is often accompanied not only by impaired function but also by structural tissue changes, like vascular proliferation, irregular collagen organisation, and hypercellularity, whereby the condition is called tendinosis. In light of the poor knowledge of tendinosis pathophysiology and recent findings of a non-neuronal signalling system in tendon tissue, the contributory role of neuropeptides such as substance P (SP) has gained increased interest. SP, known for afferent pain signalling in the nervous system, also has multiple efferent functions and has been described to be expressed by non-neuronal cells. As pain is the most prominent symptom of tendinopathy, the focus of the studies in this thesis was the innervation patterns of the tissue ventral to the Achilles tendon (i.e. the tissue targeted in many contemporary treatment methods) as well as the distribution of SP and its preferred receptor, the neurokinin-1 receptor (NK-1R), in the tendon tissue itself. It was hereby hypothesised that the source of SP affecting the Achilles tendon might be the main cells of the tendon tissue (the tenocytes) as well as paratendinous nerves, and that SP might be involved in tendinosis- development. The studies were conducted, via morphological staining methods including immunohistochemistry and in situ hybridisation, on tendon biopsies from patients suffering from Achilles tendinosis and on those from healthy volunteers. The hypothesis of the thesis was furthermore tested using an experimental animal model (rabbit) of Achilles tendinopathy, which was first validated. The model was based on a previously established overuse protocol of repetitive exercise. In the human biopsies of the tissue ventral to the Achilles tendon, there was a marked occurrence of sympathetic innervation, but also sensory, SP-containing, nerve fibres. NK-1R was expressed on blood vessels and nerve fascicles of the paratendinous tissue, but also on the tenocytes of the tendon tissue proper itself, and notably more so in patients suffering from tendinosis. Furthermore, the human tenocytes displayed not only NK-1R mRNA but also mRNA for SP. The animal model was shown to produce objectively verified tendinosis-like changes, such as hypercellularity and increased vascularity, in the rabbit Achilles tendons, after a minimum of three weeks of the exercise protocol. The contralateral leg of the animals in the model was found to be an unreliable control, as bilateral changes occured. The model furthermore demonstrated that exogenously administered SP triggers an inflammatory response in the paratendinous tissue and accelerates the intratendinous tendinosis-like changes such that they now occur after only one week of the protocol. Injections of saline as a control showed similar results as SP concerning hypercellularity, but did not lead to vascular changes or pronounced paratendinous inflammation. In summary, this thesis concludes that interactions between the peripheral sympathetic and sensory nervous systems may occur in Achilles tendinosis at the level of the ventral paratendinous tissue, a region thought to be of great importance in chronic tendon pain since many successful treatments are directed toward it. Furthermore, the distribution of NK-1R:s in the Achilles tendon described in these studies gives a basis for SP, whether produced by nerves mainly outside the tendon or by tenocytes within the tendon, to affect blood vessels, nerve structures, and/or tendon cells, especially in tendinosis patients. In light of this and of previously known SP-effects, such as stimulation of angiogenesis, pain signalling, and cell proliferation, the proposed involvement of SP in tendinosis development seems likely. Indeed, the animal model of Achilles tendon overuse confirms that SP does induce vascular proliferation and hypercellularity in tendon tissue, thus strengthening theories of SP playing a role in tendinosis pathology.

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  • 37.
    Andersson, Gustav
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi. Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Handkirurgi.
    Backman, Ludvig J.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Christensen, Jens
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Alfredson, Håkan
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Idrottsmedicin.
    Nerve distributions in insertional Achilles tendinopathy - a comparison of bone, bursae and tendon2017Inngår i: Histology and Histopathology, ISSN 0213-3911, E-ISSN 1699-5848, Vol. 32, nr 3, s. 263-270Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background/Aim. In a condition of pain in the Achilles tendon insertion there are multiple structures involved, such as the Achilles tendon itself, the retrocalcaneal bursa and a bony protrusion at the calcaneal tuberosity called Haglund's deformity. The innervation patterns of these structures are scarcely described, and the subcutaneous calcaneal bursa is traditionally not considered to be involved in the pathology. This study aimed at describing the innervation patterns of the four structures described above to provide a better understanding of possible origins of pain at the Achilles tendon insertion.

    Methods. Biopsies were taken from 10 patients with insertional Achilles tendinopathy, which had pathological changes in the subcutaneous and retrocalcaneal bursae, a Haglund deformity and Achilles tendon tendinopathy as verified by ultrasound. The biopsies were stained using immunohistochemistry in order to delineate the innervation patterns in the structures involved in insertional Achilles tendinopathy.

    Results. Immunohistochemical examinations found that the subcutaneous bursa scored the highest using a semi-quantitative evaluation of the degree of innervation when compared to the retrocalcaneal bursa, the Achilles tendon, and the calcaneal bone.

    Conclusions. These findings suggest that the subcutaneous bursa, which is traditionally not included in surgical treatment, may be a clinically important factor in insertional Achilles tendinopathy.

  • 38.
    Andersson, Gustav
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Backman, Ludvig
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Scott, Alexander
    Department of Physical Therapy, University of British Columbia, Vancouver, BC, Canada.
    Lorentzon, Ronny
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Idrottsmedicin.
    Forsgren, Sture
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Danielson, Patrik
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Substance P induces tendinosis-like changes in a rabbit model of Achilles tendon overuseManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    BACKGROUND: In previous studies we found evidence favouring that human Achilles tendon cells (tenocytes) are capable of producing the neuropeptide substance P (SP). Furthermore, the preferred receptor for SP (the neurokinin-1 receptor, NK-1 R) was widely expressed throughout the tendon, especially in patients suffering from chronic tendon pain (tendinopathy) with tissue changes (tendinosis) including hypercellularity and vascular proliferation. Considering known effects of SP, one might ask whether SP contributes to tendon cell proliferation and neovascularisation in tendinosis. We have an established animal (rabbit) model of Achilles tendinopathy based on overuse in the form of repetitive exercise. Recent studies with this model have shown that tendinosis-like changes are present after 3 weeks of exercise, but not after only 1 week. The current study aimed to test whether the development of tendinosis-like changes would be accelerated during a 1 week course of exercise with repetitive local administration of SP.

    MATERIAL AND METHODS: Four groups of animals (5-6 New Zealand white rabbits per group) were used. Three groups were subjected to the previously established protocol of Achilles tendon overuse for 1 week. One of these groups was given repetitive SP injections in the paratendinous tissue of the Achilles tendon, whereas one group (‘NaCl controls’) was given an equivalent schedule of saline injections. Two additional control groups existed: One in which the animals were neither subjected to the overuse protocol nor to any injections (‘untrained controls’), and one in which the animals trained for 1 week but were not given any injections (‘1 week controls’). Tenocyte number, vascular density, and the possible occurrence of paratendinous inflammation were evaluated. Immunohistochemistry and in situ hybridisation to detect NK-1 R were also conducted.

    RESULTS: There was a significant increase in tenocyte number in the SP-injected group compared to both untrained controls and 1 week controls. However, the same phenomenon was noticed for NaCl controls, i.e. tenocyte number was significantly increased in response to NaCl injections compared to untrained controls. There was an increase in the number of tendon blood vessels in the SP-injected group as compared to untrained controls, and this increase in vascularity was not seen for the NaCl controls or the 1 week controls. Paratendinous inflammation, as evidenced by invasion of inflammatory cells in the paratenon, was clearly more pronounced in the SP-injected group than in the NaCl controls. NK-1 R was detected in blood vessel walls, on nerves, on inflammatory cells, and on tenocytes.

    DISCUSSION AND CONCLUSIONS: The observations suggest that SP induces tenocyte proliferation and angiogenesis in the rabbit Achilles tendon, thus supporting a potential role of this neuropeptide in the processes that occur in tendinosis. The study corroborates findings on the human Achilles tendon in that NK-1 R was expressed on tenocytes and tendon blood vessel walls, thereby providing a potential anatomic basis for the observed effects of SP on the development of tendinosis. The hypercellularity observed in response to NaCl injections might be due increased tissue pressure or to stimulation of endogenous SPproduction, a phenomenon not unheard of. The angiogenic effect of SP injections, on the other hand, appeared to be more specifically related to an induction of inflammation in the paratendon.

  • 39.
    Andersson, Gustav
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Danielson, Patrik
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Alfredson, Håkan
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Idrottsmedicin.
    Forsgren, Sture
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Nerve-related characteristics of ventral paratendinous tissue in chronic Achilles tendinosis2007Inngår i: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 15, nr 10, s. 1272-1279Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ultrasound and Doppler examination has shown high blood flow-neovascularisation inside and outside the ventral Achilles tendon in chronic painful tendinosis, but not in pain-free normal Achilles tendons. In patients with Achilles tendinosis, injections with the sclerosing substance polidocanol, targeting the areas with increased blood flow, have been demonstrated to give pain relief. A drawback when interpreting these findings is the fact that the pattern of nerve supply in the target area, i.e. the ventral area of the tendon, is so far unknown. In this study, therefore, tissue specimens from this area, obtained during surgical treatment of patients with chronic painful midportion Achilles tendinosis, were examined. In the examined area, containing loose connective tissue, the general finding was a presence of large and small arteries and nerve fascicles. The nerve fascicles were distinguished in sections processed for the pan-neural marker protein gene-product 9.5. The nerve fascicles contain sensory nerve fibers, as shown via staining for the sensory markers substance P (SP) and calcitonin gene-related peptide, and sympathetic nerve fibers as seen via processing for tyrosine hydroxylase. In addition, there were immunoreactions for the SP-preferred receptor, the neurokinin-1 receptor, in blood vessel walls and nerve fascicles. Some of the blood vessels were supplied by an extensive peri-vascular innervation, sympathetic nerve fibers being a distinct component of this innervation. There was also a marked occurrence of immunoreactions for the alpha1-adrenoreceptor in arterial walls as well as in the nerve fascicles. Altogether, these findings suggest that the area investigated is under marked influence by the nervous system, including sympathetic and sensory components. Thus, sympathetic/sensory influences may be involved in the pain mechanisms from this area. In conclusion, the nerve-related characteristics of the area targeted by the polidicanol injection treatment for Achilles tendinosis, are shown here for the first time.

  • 40.
    Andersson, Gustav
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Danielson, Patrik
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Alfredson, Håkan
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Idrottsmedicin.
    Forsgren, Sture
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Presence of substance P and the neurokinin-1 receptor in tenocytes of the human Achilles tendon2008Inngår i: Regulatory Peptides, ISSN 0167-0115, E-ISSN 1873-1686, Vol. 150, nr 1-3, s. 81-87Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nerve signal substances, such as the tachykinin substance P (SP), may be involved in the changes that occur in response to tendinopathy (tendinosis). It is previously known that the level of SP innervation within tendon tissue is limited, but results of experimental studies have suggested that SP may have stimulatory, angiogenetic and healing effects in injured tendons. Therefore, it would be of interest to know if there is a local SP-supply in tendon tissue. In the present study, the patterns of expression of SP and its preferred receptor, the neurokinin-1 receptor (NK-1 R), in normal and tendinosis human Achilles tendons were analyzed by use of both immunohistochemistry and in situ hybridization. We found that there was expression of SP mRNA in tenocytes, and that tenocytes showed expression of NK-1 R at protein as well as mRNA levels. The observations concerning both SP and NK-1 R were most evident for tenocytes in tendinosis tendons. Our findings suggest that SP is produced in tendinosis tendons, and furthermore that SP has marked effects on the tenocytes via the NK-1 R. It cannot be excluded that the SP effects are of importance concerning the processes of reorganization and healing that occur for tendon tissue in tendinosis. In conclusion, it appears as if SPergic autocrine/paracrine effects occur in tendon tissue during the processes of tendinosis, hitherto unknown effects for human tendons.

  • 41.
    Andersson, Gustav
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Forsgren, Sture
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Scott, Alexander
    University of British Columbia, Vancouver, Vancouver Coastal Health and Research Institute.
    Gaida, James Edmund
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Stjernfeldt, Johanna Elgestad
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Lorentzon, Ronny
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Idrottsmedicin.
    Alfredson, Håkan
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Idrottsmedicin.
    Backman, Clas
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Handkirurgi.
    Danielson, Patrik
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Tenocyte hypercellularity and vascular proliferation in a rabbit model of tendinopathy: contralateral effects suggest the involvement of central neuronal mechanisms2011Inngår i: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 45, nr 5, s. 399-406Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objective To determine whether there are objective findings of tendinosis in a rabbit tendinopathy model on exercised and contralateral (non-exercised) Achilles tendons. Design Four groups of six New Zealand white rabbits per group were used. The animals of one (control) group were not subjected to exercise/stimulation. Interventions Animals were subjected to a protocol of electrical stimulation and passive flexion-extension of the right triceps surae muscle every second day for 1, 3 or 6 weeks. Main Outcome Measures Tenocyte number and vascular density were calculated. Morphological evaluations were also performed as well as in-situ hybridisation for vascular endothelial growth factor (VEGF) messenger RNA. Results There was a significant increase in the tenocyte number after 3 and 6 weeks of exercise, but not after 1 week, in comparison with the control group. This was seen in the Achilles tendons of both legs in experimental animals, including the unexercised limb. The pattern of vascularity showed an increase in the number of tendon blood vessels in rabbits that had exercised for 3 weeks or more, compared with those who had exercised for 1 week or not at all. VEGF-mRNA was detected in the investigated tissue, with the reactions being more clearly detected in the tendon tissue with tendinosis-like changes (6-week rabbits) than in the normal tendon tissue (control rabbits). Conclusions There were bilateral tendinosis-like changes in the Achilles tendons of rabbits in the current model after 3 weeks of training, suggesting that central neuronal mechanisms may be involved and that the contralateral side is not appropriate as a control.

  • 42.
    Andersson, Karin
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Olofsson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Holm Nielsen, Ellen
    Svehag, SvenErik
    Lundgren, Erik
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Only amyloidogenic inermediates of transthyretin induce apoptosis2002Inngår i: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 294, nr 2, s. 309-314Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In diseases like Alzheimer's disease and familial amyloidotic polyneuropathy (FAP) amyloid deposits co-localize with areas of neurodegeneration. FAP is associated with mutations of the plasma protein transthyretin (TTR). We can here show an apoptotic effect of amyloidogenic mutants of TTR on a human neuroblastoma cell line. Toxicity could be blocked by catalase indicating a free oxygen radical dependent mechanism. The toxic effect was dependent on the state of aggregation and unexpectedly mature fibrils from FAP-patients who failed to exert an apoptotic response. Morphological studies revealed a correlation between toxicity and the presence of immature amyloid. Thus, we can show that toxicity is associated with early stages of fibril formation and propose that mature full-length fibrils represent an inert end stage, which might serve as a rescue mechanism. 

  • 43. Andersson, Karin
    et al.
    Pokrzywa, M
    Dacklin, Ingrid
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Lundgren, Erik
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Inhibition of TTR aggregation-induced cell death: a new role for serum amyloid P component2013Inngår i: PLOS ONE, E-ISSN 1932-6203, Vol. 8, nr 2Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: Serum amyloid P component (SAP) is a glycoprotein that is universally found associated with different types of amyloid deposits. It has been suggested that it stabilizes amyloid fibrils and therefore protects them from proteolytic degradation.

    METHODOLOGY/PRINCIPAL FINDINGS: In this paper, we show that SAP binds not only to mature amyloid fibrils but also to early aggregates of amyloidogenic mutants of the plasma protein transthyretin (TTR). It does not inhibit fibril formation of TTR mutants, which spontaneously form amyloid in vitro at physiological pH. We found that SAP prevents cell death induced by mutant TTR, while several other molecules that are also known to decorate amyloid fibrils do not have such effect. Using a Drosophila model for TTR-associated amyloidosis, we found a new role for SAP as a protective factor in inhibition of TTR-induced toxicity. Overexpression of mutated TTR leads to a neurological phenotype with changes in wing posture. SAP-transgenic flies were crossed with mutated TTR-expressing flies and the results clearly confirmed a protective effect of SAP on TTR-induced phenotype, with an almost complete reduction in abnormal wing posture. Furthermore, we found in vivo that binding of SAP to mutated TTR counteracts the otherwise detrimental effects of aggregation of amyloidogenic TTR on retinal structure.

    CONCLUSIONS/SIGNIFICANCE: Together, these two approaches firmly establish the protective effect of SAP on TTR-induced cell death and degenerative phenotypes, and suggest a novel role for SAP through which the toxicity of early amyloidogenic aggregates is attenuated.

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  • 44.
    Andersson, Åsa
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    B cell repertoire development in normal physiology and autoimmune disease1993Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The B cell repertoire in the neonatal immune system (IS) is characterised by reactivity towards self-components, including other immunoglobulin (Ig) V-regions. These properties have been suggested to be a requirement for the development of a normal immune system. DNA sequencing of two interacting Ig idiotypes, derived from neonatal, preimmune mice, demonstrated that such idiotypic connectivity is germ- line encoded and devoid of VDJ junctional diversity. The serum levels of the same Ig idiotypes were studied in normal mice and demonstrated that the expression in serum fluctuated over time in a pattern compatible with a complex dynamic system. In contrast, similar analyses in autoimmune mice or humans demonstrated fluctuations in Ig titers that differed significantly from the healthy individuals. These findings suggested that pathological autoimmunity may be associated with fundamental alterations in the dynamics of natural antibody (ab) expression. This was further investigated in the nonobese diabetic (NOD) mouse, an animal model for human Type I diabetes. Suppression of the early B cell development in the NOD mouse prevented the development of diabetes, suggesting a role for B cells/Igs in the development of diabetes in these mice. Furthermore, neonatal injections of polyclonal Ig preparations or single, monoclonal natural abs inhibited disease induction. The prevention of diabetes development by one such natural ab was demonstrated to be dependent on both the dose injected and the timing of administration. Studies of the B cell repertoire development in NOD mice, compared to normal mice, by DNA-sequence analyses of IgVH rearrangements utilising genes from the most D-proximal Vh family, Vh7183, supported the idea of an aberrant B cell repertoire in this mouse model. Thus, the adult NOD mouse retained a neonatal pattern of Vh7183 rearrangements. This pattern could, however, be "normalised" by neonatal injection of a natural antibody, previously demonstrated to prevent the development of T cell dependent autoimmunity in the NOD mouse.

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  • 45.
    Andrade-Talavera, Yuniesky
    et al.
    Neuronal Oscillations Laboratory, Center for Alzheimer Research, Departments of NVS and KBH, Karolinska Institutet, Solna, Sweden.
    Chen, Gefei
    Department of Biosciences and Nutrition, Neo, Karolinska Institutet, 141 83 Huddinge, Sweden.
    Pansieri, Jonathan
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Arroyo-García, Luis Enrique
    Neuronal Oscillations Laboratory, Center for Alzheimer Research, Departments of NVS and KBH, Karolinska Institutet, Solna, Sweden.
    Toleikis, Zigmantas
    Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania.
    Smirnovas, Vytautas
    Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania.
    Johansson, Jan
    Department of Biosciences and Nutrition, Neo, Karolinska Institutet, 141 83 Huddinge, Sweden.
    Morozova-Roche, Ludmilla
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Fisahn, André
    Neuronal Oscillations Laboratory, Center for Alzheimer Research, Departments of NVS and KBH, Karolinska Institutet, Solna, Sweden.
    S100A9 amyloid growth and S100A9 fibril-induced impairment of gamma oscillations in area CA3 of mouse hippocampus ex vivo is prevented by Bri2 BRICHOS2022Inngår i: Progress in Neurobiology, ISSN 0301-0082, E-ISSN 1873-5118, Vol. 219, artikkel-id 102366Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The pro-inflammatory and highly amyloidogenic protein S100A9 is central to the amyloid-neuroinflammatory cascade in neurodegenerative diseases leading to cognitive impairment. Molecular chaperone activity of Bri2 BRICHOS has been demonstrated against a range of amyloidogenic polypeptides. Using a combination of thioflavin T fluorescence kinetic assay, atomic force microscopy and immuno electron microscopy we show here that recombinant Bri2 BRICHOS effectively inhibits S100A9 amyloid growth by capping amyloid fibrils. Using ex-vivo neuronal network electrophysiology in mouse brain slices we also show that both native S100A9 and amyloids of S100A9 disrupt cognition-relevant gamma oscillation power and rhythmicity in hippocampal area CA3 in a time- and protein conformation-dependent manner. Both effects were associated with Toll-like receptor 4 (TLR4) activation and were not observed upon TLR4 blockade. Importantly, S100A9 that had co-aggregated with Bri2 BRICHOS did not elicit degradation of gamma oscillations. Taken together, this work provides insights on the potential influence of S100A9 on cognitive dysfunction in Alzheimer's disease (AD) via gamma oscillation impairment from experimentally-induced gamma oscillations, and further highlights Bri2 BRICHOS as a chaperone against detrimental effects of amyloid self-assembly.

  • 46. Arai, M
    et al.
    Billker, Oliver
    Department of Biology,Imperial College of Science, Technology and Medicine, London, UK.
    Morris, H R
    Panico, M
    Delcroix, M
    Dixon, D
    Ley, S V
    Sinden, R E
    Both mosquito-derived xanthurenic acid and a host blood-derived factor regulate gametogenesis of Plasmodium in the midgut of the mosquito2001Inngår i: Molecular and biochemical parasitology (Print), ISSN 0166-6851, E-ISSN 1872-9428, Vol. 116, nr 1, s. 17-24Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Gametogenesis of Plasmodium in vitro can be induced by the combined stimulus of a 5 degrees C fall in temperature and the presence of xanthurenic acid (XA). In-vitro experiments showed that P. gallinaceum (EC(50)=80 nM) is much more sensitive to XA than P. berghei (9 microM), P. yoelii (8 microM), and P. falciparum (2 microM). However, in the mosquito vector, we do not know whether the temperature shift and XA are the only gametocyte-activating factors (GAF), nor do we know with certainty the true source(s) of XA in the mosquito blood meal. Previous studies indicate that XA is the only source of GAF in the mosquito. By defining, and then contrasting, the ability of an XA-deficient mutant of Aedes aegypti, with the wild-type mosquito to support exflagellation and ookinete formation in vivo, we determined the roles of parasite-, mosquito- and host blood-derived GAF in the regulation of gametogenesis of P. gallinaceum. Removal of both host and vector sources of GAF totally inhibited both exflagellation and ookinete production, whilst the lack of either single source resulted in only a partial reduction of exflagellation and ookinete formation in the mosquito gut. Both sources can be effectively replaced/substituted by synthetic XA. This suggests (1) both mosquito- and vertebrate-derived factors act as GAF in the mosquito gut in vivo; (2) the parasite itself is unable to produce any significant GAF activity. Studies are underway to determine whether vertebrate-derived GAF is XA. These data may form the basis of further studies of the development of new methods of interrupting malarial transmission.

  • 47. Arai, Meiji
    et al.
    Alavi, Yasmene I H
    Mendoza, Jacqueline
    Billker, Oliver
    Sinden, Robert E
    Isonicotinic acid hydrazide: an anti-tuberculosis drug inhibits malarial transmission in the mosquito gut2004Inngår i: Experimental parasitology, ISSN 0014-4894, E-ISSN 1090-2449, Vol. 106, nr 1-2, s. 30-36Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We studied the transmission-blocking effect of isonicotinic acid hydrazide (INH), a widely used anti-tuberculosis drug, against Plasmodium gallinaceum and Plasmodium berghei. INH-treatment of infected animals did not inhibit parasite development in the blood of the vertebrate host, but did inhibit exflagellation, ookinete formation, and oocyst development in the mosquito. Oocyst development was inhibited in a dose-dependent manner. The ED(50) in the P. gallinaceum/chicken/Aedes aegypti model and P. berghei/mouse/Anopheles stephensi model was 72 and 109 mg/kg, respectively. In marked contrast, in vitro exflagellation and ookinete development were not directly affected by physiological concentrations of INH. We suggest that INH exerts its inhibitory effects on the mosquito stages of the malaria parasite by an indirect, and at present undefined mechanism. Further elucidation of the mechanism how INH inhibits parasite development specifically on mosquito stages may allow us to identify new targets for malaria control strategy.

  • 48.
    Arasu, Uma Thanigai
    et al.
    Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland.
    Kärnä, Riikka
    Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland.
    Härkönen, Kai
    Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland.
    Oikari, Sanna
    Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland.
    Koistinen, Arto
    SIB Labs, University of Eastern Finland, Kuopio, Finland.
    Kröger, Heikki
    Department of Orthopaedics and Traumatology, Kuopio University Hospital, Kuopio, Finland; Bone and Cartilage Research Unit, Surgery, Institute of Clinical Medicine, University of Eastern, Finland.
    Qu, Chengjuan
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Lammi, Mikko
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). School of Public Health, Health Science Center of Xi'an Jiaotong University, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, Xi'an, PR China.
    Rilla, Kirsi
    Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland.
    Human mesenchymal stem cells secrete hyaluronan-coated extracellular vesicles2017Inngår i: Matrix Biology, ISSN 0945-053X, E-ISSN 1569-1802, Vol. 64, s. 54-68Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Extracellular vesicles (EVs) secreted by stem cells are potential factors mediating tissue regeneration. They travel from bone marrow stem cells into damaged tissues, suggesting that they can repair tissue injuries without directly replacing parenchymal cells. We have discovered that hyaluronan (HA) synthesis is associated with the shedding of HA-coated EVs. The aim of this study was to test whether bone marrow-derived hMSCs secrete HA-coated EVs. The EVs secreted by MSCs were isolated by differential centrifugation and characterized by nanoparticle tracking analysis. Their morphology and budding mechanisms were inspected by confocal microscopy and correlative light and electron microscopy. Hyaluronan synthesis of hMSCs was induced by lipopolysaccharide and inhibited by RNA interference and 4-methylumbelliferone. It was found that the MSCs have extremely long apical and lateral HA-coated filopodia, typical for cells with an active HA secretion. Additionally, they secreted HA-coated EVs carrying mRNAs for CD44 and all HAS isoforms. The results show that stem cells have a strong intrinsic potential for HA synthesis and EV secretion, and the amount of HA carried on EVs reflects the HA content of the original cells. These results show that the secretion of HA-coated EVs by hMSCs is a general process, that may contribute to many of the mechanisms of HA-mediated tissue regeneration. Additionally, an HA coat on EVs may regulate their interactions with target cells and participate in extracellular matrix remodeling.

  • 49. Arend, Andres
    et al.
    Masso, Raivo
    Masso, Marika
    Selstam, Gunnar
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Electron microscope immunocytochemical localization of cyclooxygenase-1 and-2 in pseudopregnant rat corpus luteum during luteolysis2004Inngår i: Prostaglandins & other lipid mediators, ISSN 1098-8823, E-ISSN 2212-196X, Vol. 74, nr 1-4, s. 1-10Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Prostaglandins converted from arachidonic acid by cyclooxygenases play an important regulatory role in regression of the corpus luteum. To reveal luteal distribution of cyclooxygenase isoforms during luteolysis, an electron microscope immunocytochemical study was performed. Cyclooxygenase-1 and -2 were found both in luteal steroid-producing and interstitial cells on days 13, 15 and 18 of the adult pseudopregnant rat. Cyclooxygenase-2 immunolabelling was predominantly seen in non-luteal cells. The two enzymes were localized in similar fashion to the plasma membrane, rough and smooth endoplasmic reticulum, lipid bodies and mitochondria, but differently in the nuclear compartment. Cyclooxygenase-1 labelling was found only in the perinuclear region, while cyclooxygenase-2 was localized to the nuclear envelope, region of condensed heterochromatin as well as at the perimeter of the heterochromatin. Nuclear residence may indicate additional roles for cyclooxygenase-2 in regulating gene expression. Identification of both enzymes on lipid bodies suggests that these inclusions may be involved in luteal prostanoid production.

  • 50.
    Aripaka, Karthik
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap.
    Studies on the biological functions of interaction between components in Wnt, TGF-β and HIF pathways for cancer progression2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Cancer is a disease that involves aggressive changes in the genome and aberrant signals between the living cells. Signalling pathways such as TGF-β (Transforming growth factor-β), Wnt, EGF (epidermal growth factor) and HIF (Hypoxia-inducible factor) evolved to regulate growth and development in mammals. These factors are also implicated for tumorigenesis due to failure or aberrant expression of components in these pathways. Cancer progression is a multistep process, and these steps reflect genetic alterations driving the progressive transformation of healthy human cells into highly malignant derivatives. Many types of cancers are diagnosed in the human population, such as head & neck, cervical, brain, liver, colon, prostate, uterine, breast, and renal cell cancer.

    Prostate cancer is the second most common cancer and one of the foremost leading cancer-related deaths in men in the world. Aberrant Wnt3a signals promote cancer progression through the accumulation of β-Catenin. In the first paper, we have elucidated intriguing functions for Tumour necrosis factor receptor-associated factor 6 (TRAF6) as a coregulatory factor for the expression of Wnt-target genes which was confirmed in vivo by using CRISPR/Cas9 genomic editing, in zebrafish. Our data suggest that Wnt3a promotes TRAF6 interaction with Wnt components, and TRAF6 is required for gene expression of β-Catenin as well as for the Wnt-ligand co-receptor LRP5. From the in vivo studies, we elucidated positive regulation of TRAF6, which is crucial for survival and development of zebrafish. This study identifies TRAF6 as an evolutionary conserved co-regulatory protein in the Wnt pathway that also promotes the progression of prostate and colorectal cancer due to its positive effects on Wnt3a signalling.

    Hypoxia is a condition due to O2 deprivation, and Hypoxia-inducible factors (HIF) transcription factors are responsible for the maintenance of oxygen homeostasis in living cells. Irregularities in these HIF transcription factors trigger pathological cellular responses for initiation and progression of malignant cancers. Renal cell carcinoma, malignant cancer arising in renal parenchyma and renal pelvis and, hypoxia plays a vital role in its progression. In the second paper, we have investigated the clinicopathological relevance of several hypoxic and TGF-β component proteins such as HIF-1α/2α/3α, TGF-β type 1 receptor (ALK5-FL) and the intracellular domain of ALK5 (ALK5-ICD), SNAI1 and PAI-1 with patient survival in clear cell renal cell carcinoma (ccRCC). We showed that HIF-2α associated with low cancer-specific survival. HIF-2α and SNAI1 positively correlated with ALK5-ICD, pSMAD2/3, PAI-1 and SNAI1 with HIF-2α; HIF-1α positively correlated with pSMAD2/3. Further, under normoxic conditions, our data suggest that ALK5 interacts with HIF-1α and HIF-2α, and promotes their expression and target genes such as GLUT1 and CA9, in a VHL dependent manner through its kinase activity. These findings shed light on the critical aspect of cross-talk between TGF-β signalling and hypoxia pathway, and also the novel finding of an interaction between ALK5 and HIF-α might provide a more in-depth understanding of mechanisms behind tumour progression

    In the third paper, an ongoing study, we investigated the role of HIF-3α in the progression of Renal cell carcinoma and its association with the components of TGF-β and HIF pathways. We have observed increased levels of HIF-3α in ccRCC and pRCC (papillary renal cell carcinoma) which are associated with advanced tumour stage, metastasis and larger tumours. Also, we found HIF-3α show a significant positive association with pro-invasive gene SNAI1, which is a crucial regulator of epithelial to mesenchymal transition. TRAF6 an E3 ligase known to be a prognostic marker in RCC and we observed HIF-3α associates with TRAF6.

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