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Zhang J, Li Y, Gong A, Wang J. From proteome to pathogenesis: investigating polycystic ovary syndrome with Mendelian randomization analysis. Front Endocrinol (Lausanne) 2024; 15:1442483. [PMID: 39314522 PMCID: PMC11417002 DOI: 10.3389/fendo.2024.1442483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2024] [Accepted: 08/21/2024] [Indexed: 09/25/2024] Open
Abstract
Background Polycystic ovary syndrome (PCOS) is defined by oligo/anovulation, hyperandrogenism, and polycystic ovaries with uncertain pathogenesis. The proteome represents a substantial source of therapeutic targets, and their coding genes may elucidate the mechanisms underlying PCOS. However, reports on the profiles of the human plasma protein-coding genes and PCOS are limited. Here, we aimed to investigate novel biomarkers or drug targets for PCOS by integrating genetics and the human plasma proteome. Methods Our study acquired the protein quantitative trait loci from DECODE Genetics, offering 4,907 proteins in 35,559 individuals while obtaining PCOS summary statistics by accessing the FinnGen biobank (1,639 cases and 218,970 controls) and the genome-wide association study catalog (797 cases and 140,558 controls). Herein, we sequentially used two-sample Mendelian randomization (MR) analyses and colocalization to verify the causal link between candidate proteins, their coding genes, and PCOS. Further PCOS data download was conducted by accessing the Gene Expression Omnibus and Zenodo platforms. Gene expression level analysis, pathway enrichment analysis, immune cell infiltration, and transcription factor prediction were performed, aiming at detecting specific cell types with enriched expression and exploring potential optimized treatments for PCOS. Results MR analysis revealed 243 protein-coding genes with a causal relationship to PCOS risk, of which 12 were prioritized with the most significant evidence. Through colocalization analysis, three key genes, CUB domain-containing protein 1 (CDCP1), glutaredoxin 2 (GLRX2), and kirre-like nephrin family adhesion molecule 2 (KIRREL2), were identified. Subsequently, the three genes were strongly related to immune function and metabolism in terms of biological significance. In single-cell analysis, the expression levels of genes in ovarian theca cells were explored. Conclusion Overall, three protein-coding genes (CDCP1, GLRX2, and KIRREL2) may be related to a higher PCOS risk, suggesting that they may be entry points for exploration of PCOS pathogenesis and treatment, warranting further clinical investigations.
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Affiliation(s)
- Jiaqi Zhang
- Department of Digestive Endoscopy, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Yuqing Li
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Aixia Gong
- Department of Digestive Endoscopy, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Jingmin Wang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
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2
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Kameyama T, Miyata M, Shiotani H, Adachi J, Kakuta S, Uchiyama Y, Mizutani K, Takai Y. Heterogeneity of perivascular astrocyte endfeet depending on vascular regions in the mouse brain. iScience 2023; 26:108010. [PMID: 37829206 PMCID: PMC10565786 DOI: 10.1016/j.isci.2023.108010] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 07/14/2023] [Accepted: 09/18/2023] [Indexed: 10/14/2023] Open
Abstract
Astrocytes interact with not only synapses but also brain blood vessels through perivascular astrocyte endfeet (PV-AEF) to form the neurovascular unit (NVU). However, PV-AEF components have not been fully identified. Here, we biochemically isolated blood vessels from mouse brain homogenates and purified PV-AEF. The purified PV-AEF were observed in different sizes, similar to PV-AEF on brain blood vessels. Mass spectrometry analysis identified 9,762 proteins in the purified PV-AEF, including cell adhesion molecules, nectin-2δ, Kirrel2, and podoplanin. Immunofluorescence microscopic analysis revealed that nectin-2δ and podoplanin were concentrated mainly in arteries/arterioles and veins/venules of the mouse brain, whereas Kirrel2 was mainly in arteries/arterioles. Nectin-2α/δ, Kirrel2, and podoplanin were preferentially observed in large sizes of the purified PV-AEF. Furthermore, Kirrel2 potentially has cell adhesion activity of cultured astrocytes. Collectively, these results indicate that PV-AEF have heterogeneity in sizes and molecular components, implying different roles of PV-AEF in NVU function depending on vascular regions.
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Affiliation(s)
- Takeshi Kameyama
- Division of Pathogenetic Signaling, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe 650-0047, Japan
- Department of Immunology and Parasitology, Graduate School of Medicine, Tokushima University, Tokushima 770-8503, Japan
| | - Muneaki Miyata
- Division of Pathogenetic Signaling, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe 650-0047, Japan
- Division of Pathogenetic Signaling, Institute of Advanced Medical Sciences, Tokushima University, Tokushima 770-8503, Japan
| | - Hajime Shiotani
- Division of Pathogenetic Signaling, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe 650-0047, Japan
- Division of Pathogenetic Signaling, Institute of Advanced Medical Sciences, Tokushima University, Tokushima 770-8503, Japan
| | - Jun Adachi
- Laboratory of Proteomics for Drug Discovery, Center for Drug Design Research, National Institute of Biomedical Innovation, Health and Nutrition, Osaka 567-0085, Japan
- Laboratory of Clinical and Analytical Chemistry, Center for Drug Design Research, National Institute of Biomedical Innovation, Health and Nutrition, Osaka 567-0085, Japan
| | - Soichiro Kakuta
- Laboratory of Morphology and Image Analysis, Biomedical Research Core Facilities, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan
- Department of Cellular Molecular Neuropathology, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan
| | - Yasuo Uchiyama
- Department of Cellular Molecular Neuropathology, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan
| | - Kiyohito Mizutani
- Division of Pathogenetic Signaling, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe 650-0047, Japan
- Division of Pathogenetic Signaling, Institute of Advanced Medical Sciences, Tokushima University, Tokushima 770-8503, Japan
| | - Yoshimi Takai
- Division of Pathogenetic Signaling, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe 650-0047, Japan
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Eriksson M, Litwak SA, Yun Y, Stanley WJ, Thorn P, Ahlgren U, Gurzov EN. Insulin-Binding Peptide Probes Provide a Novel Strategy for Pancreatic β-Cell Imaging. Mol Pharm 2021; 18:4428-4436. [PMID: 34649437 DOI: 10.1021/acs.molpharmaceut.1c00616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Type 1 diabetes develops in childhood and adolescence, with peak incidence in the early teenage years. There is an urgent need for an accurate method to detect insulin-producing β-cells in patients that is not affected by alterations in β-cell function. As part of our research program to design specific probes to measure β-cell mass, we recently developed a novel insulin-binding peptide probe (IBPP) for the detection of β-cells in vivo. Here, we applied our innovative method to show specific labeling of this IBPP to human and mouse fixed β-cells in pancreatic islets. Importantly, we showed staining of human and mouse islets in culture without any negative functional or cell viability impact. Moreover, the IBPP-stained mouse islets after tail vein injection in vivo, albeit with batch differences in staining efficiency. In conclusion, we provide evidence showing that the IBPP can be used for future accurate detection of β-cell mass in a variety of preclinical models of diabetes.
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Affiliation(s)
- Maria Eriksson
- Umeå Centre for Molecular Medicine, Umeå University, Johan Bures väg 12, Umeå 901 87, Sweden
| | - Sara A Litwak
- St Vincent's Institute of Medical Research, 9 Princes Street, Melbourne 3065, Australia
| | - Yan Yun
- Charles Perkins Centre, Discipline of Physiology, School of Medical Sciences, University of Sydney, Johns Hopkins Dr, Sydney 2006, Australia
| | - William J Stanley
- St Vincent's Institute of Medical Research, 9 Princes Street, Melbourne 3065, Australia.,Department of Medicine, The University of Melbourne, Parkville, Melbourne 3065, Australia
| | - Peter Thorn
- Charles Perkins Centre, Discipline of Physiology, School of Medical Sciences, University of Sydney, Johns Hopkins Dr, Sydney 2006, Australia
| | - Ulf Ahlgren
- Umeå Centre for Molecular Medicine, Umeå University, Johan Bures väg 12, Umeå 901 87, Sweden
| | - Esteban N Gurzov
- Department of Medicine, The University of Melbourne, Parkville, Melbourne 3065, Australia.,Signal Transduction and Metabolism Laboratory, Laboratoire de Gastroentérologie Expérimental et Endotools, Université libre de Bruxelles, Route de Lennik 808, Brussels 1070, Belgium
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Park S, Kim Y, Lee J, Lee JY, Kim H, Lee S, Oh CM. A Systems Biology Approach to Investigating the Interaction between Serotonin Synthesis by Tryptophan Hydroxylase and the Metabolic Homeostasis. Int J Mol Sci 2021; 22:ijms22052452. [PMID: 33671067 PMCID: PMC7957782 DOI: 10.3390/ijms22052452] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/11/2021] [Accepted: 02/24/2021] [Indexed: 12/19/2022] Open
Abstract
Obesity has become a global public health and economic problem. Obesity is a major risk factor for a number of complications, such as type 2 diabetes, cardiovascular disease, fatty liver disease, and cancer. Serotonin (5-hydroxytryptamine [5-HT]) is a biogenic monoamine that plays various roles in metabolic homeostasis. It is well known that central 5-HT regulates appetite and mood. Several 5-HT receptor agonists and selective serotonin receptor uptake inhibitors (SSRIs) have shown beneficial effects on appetite and mood control in clinics. Although several genetic polymorphisms related to 5-HT synthesis and its receptors are strongly associated with obesity, there is little evidence of the role of peripheral 5-HT in human metabolism. In this study, we performed a systemic analysis of transcriptome data from the Genotype-Tissue Expression (GTEX) database. We investigated the expression of 5-HT and tryptophan hydroxylase (TPH), the rate-limiting enzyme of 5-HT biosynthesis, in the human brain and peripheral tissues. We also performed differential gene expression analysis and predicted changes in metabolites by comparing gene expressions of tissues with high TPH expression to the gene expressions of tissues with low TPH expression. Our analyses provide strong evidence that serotonin plays an important role in the regulation of metabolic homeostasis in humans.
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Affiliation(s)
- Suhyeon Park
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea; (S.P.); (Y.K.); (J.L); (J.Y.L.)
| | - Yumin Kim
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea; (S.P.); (Y.K.); (J.L); (J.Y.L.)
| | - Jibeom Lee
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea; (S.P.); (Y.K.); (J.L); (J.Y.L.)
| | - Jeong Yun Lee
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea; (S.P.); (Y.K.); (J.L); (J.Y.L.)
| | - Hail Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea;
| | - Sunjae Lee
- Department of School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
- Correspondence: (S.L.); (C.-M.O.); Tel.: +82-10-7304-1213 (S.L.)
| | - Chang-Myung Oh
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea; (S.P.); (Y.K.); (J.L); (J.Y.L.)
- Correspondence: (S.L.); (C.-M.O.); Tel.: +82-10-7304-1213 (S.L.)
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Bravatà V, Minafra L, Cammarata FP, Pisciotta P, Lamia D, Marchese V, Petringa G, Manti L, Cirrone GA, Gilardi MC, Cuttone G, Forte GI, Russo G. Gene expression profiling of breast cancer cell lines treated with proton and electron radiations. Br J Radiol 2018; 91:20170934. [PMID: 29888960 DOI: 10.1259/bjr.20170934] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
OBJECTIVE Technological advances in radiation therapy are evolving with the use of hadrons, such as protons, indicated for tumors where conventional radiotherapy does not give significant advantages or for tumors located in sensitive regions, which need the maximum of dose-saving of the surrounding healthy tissues. The genomic response to conventional and non-conventional linear energy transfer exposure is a poor investigated topic and became an issue of radiobiological interest. The aim of this work was to analyze and compare molecular responses in term of gene expression profiles, induced by electron and proton irradiation in breast cancer cell lines. METHODS We studied the gene expression profiling differences by cDNA microarray activated in response to electron and proton irradiation with different linear energy transfer values, among three breast cell lines (the tumorigenic MCF7 and MDA-MB-231 and the non-tumorigenic MCF10A), exposed to the same sublethal dose of 9 Gy. RESULTS Gene expression profiling pathway analyses showed the activation of different signaling and molecular networks in a cell line and radiation type-dependent manner. MCF10A and MDA-MB-231 cell lines were found to induce factors and pathways involved in the immunological process control. CONCLUSION Here, we describe in a detailed way the gene expression profiling and pathways activated after electron and proton irradiation in breast cancer cells. Summarizing, although specific pathways are activated in a radiation type-dependent manner, each cell line activates overall similar molecular networks in response to both these two types of ionizing radiation. Advances in knowledge: In the era of personalized medicine and breast cancer target-directed intervention, we trust that this study could drive radiation therapy towards personalized treatments, evaluating possible combined treatments, based on the molecular characterization.
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Affiliation(s)
- Valentina Bravatà
- 1 Institute of Molecular Bioimaging and Physiology, National Research Council (IBFM-CNR) , Cefalù , Italy
| | - Luigi Minafra
- 1 Institute of Molecular Bioimaging and Physiology, National Research Council (IBFM-CNR) , Cefalù , Italy
| | - Francesco Paolo Cammarata
- 1 Institute of Molecular Bioimaging and Physiology, National Research Council (IBFM-CNR) , Cefalù , Italy
| | - Pietro Pisciotta
- 1 Institute of Molecular Bioimaging and Physiology, National Research Council (IBFM-CNR) , Cefalù , Italy.,2 National Institute for Nuclear Physics, Laboratori Nazionali del Sud, INFN-LNS , Catania , Italy.,3 Department of Physics and Astronomy, University of Catania , Catania , Italy
| | - Debora Lamia
- 1 Institute of Molecular Bioimaging and Physiology, National Research Council (IBFM-CNR) , Cefalù , Italy
| | - Valentina Marchese
- 2 National Institute for Nuclear Physics, Laboratori Nazionali del Sud, INFN-LNS , Catania , Italy
| | - Giada Petringa
- 2 National Institute for Nuclear Physics, Laboratori Nazionali del Sud, INFN-LNS , Catania , Italy
| | - Lorenzo Manti
- 4 Department of Physics, University of Naples Federico II, via Cintia, I-80126 Naples , Italy
| | - Giuseppe Ap Cirrone
- 2 National Institute for Nuclear Physics, Laboratori Nazionali del Sud, INFN-LNS , Catania , Italy
| | - Maria Carla Gilardi
- 1 Institute of Molecular Bioimaging and Physiology, National Research Council (IBFM-CNR) , Cefalù , Italy.,5 Department of Health Sciences, Tecnomed Foundation, University of Milano-Bicocca , Milan , Italy
| | - Giacomo Cuttone
- 2 National Institute for Nuclear Physics, Laboratori Nazionali del Sud, INFN-LNS , Catania , Italy
| | - Giusi Irma Forte
- 1 Institute of Molecular Bioimaging and Physiology, National Research Council (IBFM-CNR) , Cefalù , Italy
| | - Giorgio Russo
- 1 Institute of Molecular Bioimaging and Physiology, National Research Council (IBFM-CNR) , Cefalù , Italy.,2 National Institute for Nuclear Physics, Laboratori Nazionali del Sud, INFN-LNS , Catania , Italy
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6
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A functional variant in NEPH3 gene confers high risk of renal failure in primary hematuric glomerulopathies. Evidence for predisposition to microalbuminuria in the general population. PLoS One 2017; 12:e0174274. [PMID: 28334007 PMCID: PMC5363870 DOI: 10.1371/journal.pone.0174274] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 03/06/2017] [Indexed: 01/06/2023] Open
Abstract
Background Recent data emphasize that thin basement membrane nephropathy (TBMN) should not be viewed as a form of benign familial hematuria since chronic renal failure (CRF) and even end-stage renal disease (ESRD), is a possible development for a subset of patients on long-term follow-up, through the onset of focal and segmental glomerulosclerosis (FSGS). We hypothesize that genetic modifiers may explain this variability of symptoms. Methods We looked in silico for potentially deleterious functional SNPs, using very strict criteria, in all the genes significantly expressed in the slit diaphragm (SD). Two variants were genotyped in a cohort of well-studied adult TBMN patients from 19 Greek-Cypriot families, with a homogeneous genetic background. Patients were categorized as “Severe” or “Mild”, based on the presence or not of proteinuria, CRF and ESRD. A larger pooled cohort (HEMATURIA) of 524 patients, including IgA nephropathy patients, was used for verification. Additionally, three large general population cohorts [Framingham Heart Study (FHS), KORAF4 and SAPHIR] were used to investigate if the NEPH3-V353M variant has any renal effect in the general population. Results and conclusions Genotyping for two high-scored variants in 103 TBMN adult patients with founder mutations who were classified as mildly or severely affected, pointed to an association with variant NEPH3-V353M (filtrin). This promising result prompted testing in the larger pooled cohort (HEMATURIA), indicating an association of the 353M variant with disease severity under the dominant model (p = 3.0x10-3, OR = 6.64 adjusting for gender/age; allelic association: p = 4.2x10-3 adjusting for patients’ kinships). Subsequently, genotyping 6,531 subjects of the Framingham Heart Study (FHS) revealed an association of the homozygous 353M/M genotype with microalbuminuria (p = 1.0x10-3). Two further general population cohorts, KORAF4 and SAPHIR confirmed the association, and a meta-analysis of all three cohorts (11,258 individuals) was highly significant (p = 1.3x10-5, OR = 7.46). Functional studies showed that Neph3 homodimerization and Neph3-Nephrin heterodimerization are disturbed by variant 353M. Additionally, 353M was associated with differential activation of the unfolded protein response pathway, when overexpressed in stressed cultured undifferentiated podocyte cells, thus attesting to its functional significance. Genetics and functional studies support a “rare variant-strong effect” role for NEPH3-V353M, by exerting a negative modifier effect on primary glomerular hematuria. Additionally, genetics studies provide evidence for a role in predisposing homozygous subjects of the general population to micro-albuminuria.
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7
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Grahammer F, Wigge C, Schell C, Kretz O, Patrakka J, Schneider S, Klose M, Kind J, Arnold SJ, Habermann A, Bräuniger R, Rinschen MM, Völker L, Bregenzer A, Rubbenstroth D, Boerries M, Kerjaschki D, Miner JH, Walz G, Benzing T, Fornoni A, Frangakis AS, Huber TB. A flexible, multilayered protein scaffold maintains the slit in between glomerular podocytes. JCI Insight 2016; 1:86177. [PMID: 27430022 DOI: 10.1172/jci.insight.86177] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Vertebrate life critically depends on renal filtration and excretion of low molecular weight waste products. This process is controlled by a specialized cell-cell contact between podocyte foot processes: the slit diaphragm (SD). Using a comprehensive set of targeted KO mice of key SD molecules, we provided genetic, functional, and high-resolution ultrastructural data highlighting a concept of a flexible, dynamic, and multilayered architecture of the SD. Our data indicate that the mammalian SD is composed of NEPHRIN and NEPH1 molecules, while NEPH2 and NEPH3 do not participate in podocyte intercellular junction formation. Unexpectedly, homo- and heteromeric NEPHRIN/NEPH1 complexes are rarely observed. Instead, single NEPH1 molecules appear to form the lower part of the junction close to the glomerular basement membrane with a width of 23 nm, while single NEPHRIN molecules form an adjacent junction more apically with a width of 45 nm. In both cases, the molecules are quasiperiodically spaced 7 nm apart. These structural findings, in combination with the flexibility inherent to the repetitive Ig folds of NEPHRIN and NEPH1, indicate that the SD likely represents a highly dynamic cell-cell contact that forms an adjustable, nonclogging barrier within the renal filtration apparatus.
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Affiliation(s)
- Florian Grahammer
- Department of Medicine, Division of Nephrology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Christoph Wigge
- Buchmann Institute for Molecular Life Sciences and Institute for Biophysics, Goethe University Frankfurt, Frankfurt, Germany
| | - Christoph Schell
- Department of Medicine, Division of Nephrology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine.,Faculty of Biology, and
| | - Oliver Kretz
- Department of Medicine, Division of Nephrology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BIOSS Center for Biological Signalling Studies, Albert-Ludwigs University of Freiburg, Freiburg, Germany.,Institute of Anatomy, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jaakko Patrakka
- KI/AZ Integrated Cardio-Metabolic Center (ICMC), Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Simon Schneider
- Department of Medicine, Division of Nephrology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Martin Klose
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,German Cancer Consortium and.,German Cancer Research Center, Heidelberg, Germany
| | - Julia Kind
- Department of Medicine, Division of Nephrology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Sebastian J Arnold
- Department of Medicine, Division of Nephrology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BIOSS Center for Biological Signalling Studies, Albert-Ludwigs University of Freiburg, Freiburg, Germany.,Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Anja Habermann
- Buchmann Institute for Molecular Life Sciences and Institute for Biophysics, Goethe University Frankfurt, Frankfurt, Germany
| | - Ricarda Bräuniger
- Buchmann Institute for Molecular Life Sciences and Institute for Biophysics, Goethe University Frankfurt, Frankfurt, Germany
| | - Markus M Rinschen
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Linus Völker
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Andreas Bregenzer
- Department of Medicine, Division of Nephrology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Dennis Rubbenstroth
- Institute of Virology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Melanie Boerries
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,German Cancer Consortium and.,German Cancer Research Center, Heidelberg, Germany
| | | | - Jeffrey H Miner
- Renal Division, Washington University, St. Louis, Missouri, USA
| | - Gerd Walz
- Department of Medicine, Division of Nephrology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Thomas Benzing
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Alessia Fornoni
- Division of Nephrology and Katz Family Drug Discovery Center, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Achilleas S Frangakis
- Buchmann Institute for Molecular Life Sciences and Institute for Biophysics, Goethe University Frankfurt, Frankfurt, Germany
| | - Tobias B Huber
- Department of Medicine, Division of Nephrology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine.,BIOSS Center for Biological Signalling Studies, Albert-Ludwigs University of Freiburg, Freiburg, Germany.,FRIAS, Freiburg Institute for Advanced Studies and ZBSA, Center for Biological System Analysis, Albert-Ludwigs-University of Freiburg, Germany
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8
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Morales Diaz H, Mejares E, Newman-Smith E, Smith WC. ACAM, a novel member of the neural IgCAM family, mediates anterior neural tube closure in a primitive chordate. Dev Biol 2016; 409:288-296. [PMID: 26542009 DOI: 10.1016/j.ydbio.2015.10.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 10/30/2015] [Accepted: 10/30/2015] [Indexed: 01/18/2023]
Abstract
The neural IgCAM family of cell adhesion molecules, which includes NCAM and related molecules, has evolved via gene duplication and alternative splicing to allow for a wide range of isoforms with distinct functions and homophilic binding properties. A search for neural IgCAMs in ascidians (Ciona intestinalis, Ciona savignyi, and Phallusia mammillata) has identified a novel set of truncated family members that, unlike the known members, lack fibronectin III domains and consist of only repeated Ig domains. Within the tunicates this form appears to be unique to the ascidians, and it was designated ACAM, for Ascidian Cell Adhesion Molecule. In C. intestinalis ACAM is expressed in the developing neural plate and neural tube, with strongest expression in the anterior sensory vesicle precursor. Unlike the two other conventional neural IgCAMs in C. intestinalis, which are expressed maternally and throughout the morula and blastula stages, ACAM expression initiates at the gastrula stage. Moreover, C. intestinalis ACAM is a target of the homeodomain transcription factor OTX, which plays an essential role in the development of the anterior central nervous system. Morpholino (MO) knockdown shows that ACAM is required for neural tube closure. In MO-injected embryos neural tube closure was normal caudally, but the anterior neuropore remained open. A similar phenotype was seen with overexpression of a secreted version of ACAM. The presence of ACAM in ascidians highlights the diversity of this gene family in morphogenesis and neurodevelopment.
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Affiliation(s)
- Heidi Morales Diaz
- Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA, United States
| | - Emil Mejares
- Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA, United States
| | - Erin Newman-Smith
- Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA, United States
| | - William C Smith
- Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA, United States.
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9
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Yesildag B, Bock T, Herrmanns K, Wollscheid B, Stoffel M. Kin of IRRE-like Protein 2 Is a Phosphorylated Glycoprotein That Regulates Basal Insulin Secretion. J Biol Chem 2015; 290:25891-906. [PMID: 26324709 DOI: 10.1074/jbc.m115.684704] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Indexed: 12/17/2022] Open
Abstract
Direct interactions among pancreatic β-cells via cell surface proteins inhibit basal and enhance stimulated insulin secretion. Here, we functionally and biochemically characterized Kirrel2, an immunoglobulin superfamily protein with β-cell-specific expression in the pancreas. Our results show that Kirrel2 is a phosphorylated glycoprotein that co-localizes and interacts with the adherens junction proteins E-cadherin and β-catenin in MIN6 cells. We further demonstrate that the phosphosites Tyr(595-596) are functionally relevant for the regulation of Kirrel2 stability and localization. Analysis of the extracellular and intracellular domains of Kirrel2 revealed that it is cleaved and shed from MIN6 cells and that the remaining membrane spanning cytoplasmic domain is processed by γ-secretase complex. Kirrel2 knockdown with RNA interference in MIN6 cells and ablation of Kirrel2 from mice with genetic deletion resulted in increased basal insulin secretion from β-cells, with no immediate influence on stimulated insulin secretion, total insulin content, or whole body glucose metabolism. Our results show that in pancreatic β-cells Kirrel2 localizes to adherens junctions, is regulated by multiple post-translational events, including glycosylation, extracellular cleavage, and phosphorylation, and engages in the regulation of basal insulin secretion.
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Affiliation(s)
- Burcak Yesildag
- From the Department of Biology, Institute of Molecular Health Sciences, Swiss Federal Institute of Technology (ETH) Zurich, Otto-Stern-Weg 7, 8093 Zurich
| | - Thomas Bock
- the Department of Health Sciences and Technology, Institute of Molecular Systems Biology, Swiss Federal Institute of Technology Zurich, Auguste-Piccard-Hof 1, 8093 Zurich, and
| | - Karolin Herrmanns
- From the Department of Biology, Institute of Molecular Health Sciences, Swiss Federal Institute of Technology (ETH) Zurich, Otto-Stern-Weg 7, 8093 Zurich
| | - Bernd Wollscheid
- the Department of Health Sciences and Technology, Institute of Molecular Systems Biology, Swiss Federal Institute of Technology Zurich, Auguste-Piccard-Hof 1, 8093 Zurich, and
| | - Markus Stoffel
- From the Department of Biology, Institute of Molecular Health Sciences, Swiss Federal Institute of Technology (ETH) Zurich, Otto-Stern-Weg 7, 8093 Zurich, the Department of Health Sciences and Technology, Institute of Molecular Systems Biology, Swiss Federal Institute of Technology Zurich, Auguste-Piccard-Hof 1, 8093 Zurich, and the Faculty of Medicine, University of Zurich, 8091 Zurich, Switzerland
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10
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Lüthy K, Ahrens B, Rawal S, Lu Z, Tarnogorska D, Meinertzhagen IA, Fischbach KF. The irre cell recognition module (IRM) protein Kirre is required to form the reciprocal synaptic network of L4 neurons in the Drosophila lamina. J Neurogenet 2014; 28:291-301. [PMID: 24697410 DOI: 10.3109/01677063.2014.883390] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Each neuropil module, or cartridge, in the fly's lamina has a fixed complement of cells. Of five types of monopolar cell interneurons, only L4 has collaterals that invade neighboring cartridges. In the proximal lamina, these collaterals form reciprocal synapses with both the L2 of their own cartridge and the L4 collateral branches from two other neighboring cartridges. During synaptogenesis, L4 collaterals strongly express the cell adhesion protein Kirre, a member of the irre cell recognition module (IRM) group of proteins ( Fischbach et al., 2009 , J Neurogenet, 23, 48-67). The authors show by mutant analysis and gene knockdown techniques that L4 neurons develop their lamina collaterals in the absence of this cell adhesion protein. Using electron microscopy (EM), the authors demonstrate, however, that without Kirre protein these L4 collaterals selectively form fewer synapses. The collaterals of L4 neurons of various genotypes reconstructed from serial-section EM revealed that the number of postsynaptic sites was dramatically reduced in the absence of Kirre, almost eliminating any synaptic input to L4 neurons. A significant reduction of presynaptic sites was also detected in kirre(0) mutants and gene knockdown flies using RNA interference. L4 neuron reciprocal synapses are thus almost eliminated. A presynaptic marker, Brp-short(GFP) confirmed these data using confocal microscopy. This study reveals that removing Kirre protein specifically disrupts the functional L4 synaptic network in the Drosophila lamina.
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Affiliation(s)
- Kevin Lüthy
- Faculty of Biology, Albert-Ludwigs University Freiburg , Germany
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11
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Ex vivo expansion of functional human UCB-HSCs/HPCs by coculture with AFT024-hkirre cells. BIOMED RESEARCH INTERNATIONAL 2014; 2014:412075. [PMID: 24719861 PMCID: PMC3955665 DOI: 10.1155/2014/412075] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 11/30/2013] [Accepted: 12/16/2013] [Indexed: 01/05/2023]
Abstract
Kiaa1867 (human Kirre, hKirre) has a critical role in brain development and/or maintenance of the glomerular slit diaphragm in kidneys. Murine homolog of this gene, mKirre expressed in OP9 and AFT024 cells could support hematopoietic stem cells/hematopoietic progenitor cells (HSC/HPC) expansion in vitro. HKirre is also expressed in human FBMOB-hTERT cell line and fetal liver fibroblast-like cells but its function has remained unclear. In this paper, we cloned a hKirre gene from human fetal liver fibroblast-like cells and established a stably overexpressing hKirre-AFT024 cell line. Resultant cells could promote self-renewal and ex vivo expansion of HSCs/HPCs significantly higher than AFT024-control cells transformed with mock plasmid. The Expanded human umbilical cord blood (hUCB) CD34+ cells retained the capacity of multipotent differentiation as long as 8 weeks and successfully repopulated the bone marrow of sublethally irradiated NOD/SCID mice, which demonstrated the expansion of long-term primitive transplantable HSCs/HPCs. Importantly, hkirre could upregulate the expressions of Wnt-5A, BMP4, and SDF-1 and downregulate TGF-β with other hematopoietic growth factors. By SDS-PAGE and Western Blot analysis, a ~89 kDa protein in total lysate of AFT024-hKirre was identified. Supernatants from AFT024-hkirre could also support CD34+CD38− cells expansion. These results demonstrated that the AFT024-hKirre cells have the ability to efficiently expand HSCs/HPCs.
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12
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Identification and expression of immune genes in the flat oyster Ostrea edulis in response to bonamiosis. Gene 2012; 492:81-93. [DOI: 10.1016/j.gene.2011.11.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 10/25/2011] [Accepted: 11/01/2011] [Indexed: 12/26/2022]
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13
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Babu K, Hu Z, Chien SC, Garriga G, Kaplan JM. The immunoglobulin super family protein RIG-3 prevents synaptic potentiation and regulates Wnt signaling. Neuron 2011; 71:103-16. [PMID: 21745641 DOI: 10.1016/j.neuron.2011.05.034] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/12/2011] [Indexed: 11/15/2022]
Abstract
Cell surface Ig superfamily proteins (IgSF) have been implicated in several aspects of neuron development and function. Here, we describe the function of a Caenorhabditis elegans IgSF protein, RIG-3. Mutants lacking RIG-3 have an exaggerated paralytic response to a cholinesterase inhibitor, aldicarb. Although RIG-3 is expressed in motor neurons, heightened drug responsiveness was caused by an aldicarb-induced increase in muscle ACR-16 acetylcholine receptor (AChR) abundance, and a corresponding potentiation of postsynaptic responses at neuromuscular junctions. Mutants lacking RIG-3 also had defects in the anteroposterior polarity of the ALM mechanosensory neurons. The effects of RIG-3 on synaptic transmission and ALM polarity were both mediated by changes in Wnt signaling, and in particular by inhibiting CAM-1, a Ror-type receptor tyrosine kinase that binds Wnt ligands. These results identify RIG-3 as a regulator of Wnt signaling, and suggest that RIG-3 has an anti-plasticity function that prevents activity-induced changes in postsynaptic receptor fields.
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Affiliation(s)
- Kavita Babu
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
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14
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Rochlin K, Yu S, Roy S, Baylies MK. Myoblast fusion: when it takes more to make one. Dev Biol 2009; 341:66-83. [PMID: 19932206 DOI: 10.1016/j.ydbio.2009.10.024] [Citation(s) in RCA: 177] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2009] [Revised: 10/14/2009] [Accepted: 10/14/2009] [Indexed: 01/09/2023]
Abstract
Cell-cell fusion is a crucial and highly regulated event in the genesis of both form and function of many tissues. One particular type of cell fusion, myoblast fusion, is a key cellular process that shapes the formation and repair of muscle. Despite its importance for human health, the mechanisms underlying this process are still not well understood. The purpose of this review is to highlight the recent literature pertaining to myoblast fusion and to focus on a comparison of these studies across several model systems, particularly the fly, zebrafish and mouse. Advances in technical analysis and imaging have allowed identification of new fusion genes and propelled further characterization of previously identified genes in each of these systems. Among the cellular steps identified as critical for myoblast fusion are migration, recognition, adhesion, membrane alignment and membrane pore formation and resolution. Importantly, striking new evidence indicates that orthologous genes govern several of these steps across these species. Taken together, comparisons across three model systems are illuminating a once elusive process, providing exciting new insights and a useful framework of genes and mechanisms.
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Affiliation(s)
- Kate Rochlin
- Program in Developmental Biology, Sloan-Kettering Institute, New York, NY 10065, USA
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15
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Nishida K, Hoshino M, Kawaguchi Y, Murakami F. Ptf1a directly controls expression of immunoglobulin superfamily molecules Nephrin and Neph3 in the developing central nervous system. J Biol Chem 2009; 285:373-80. [PMID: 19887377 DOI: 10.1074/jbc.m109.060657] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ptf1a, a basic helix-loop-helix transcription factor, plays an indispensable role for cell fate specification of subsets of neurons in the developing central nervous system. However, downstream molecules induced by Ptf1a during neural development have not been well characterized. In the present study, we identified immunoglobulin superfamily molecules, Nephrin and Neph3, as direct downstream targets of Ptf1a. First, the expression domains of Nephrin and Neph3 closely resembled those of Ptf1a in the developing retina, hypothalamus, cerebellum, hindbrain, and spinal cord. Second, Ptf1a bound directly to a PTF-binding motif in the 5'-flanking region of Nephrin and Neph3 genes. Third, Ptf1a activated transcription driven by the 5'-flanking region of these genes. Finally, the expression of Nephrin and Neph3 was lost in Ptf1a-null mice, whereas ectopic expression of Nephrin and Neph3 was induced by forced expression of Ptf1a. We provided further evidence that Nephrin and Neph3 could interact homophilically and heterophilically, suggesting that Nephrin and Neph3 might regulate certain developmental aspects of Ptf1a-positive neurons as homo- or heterooligomers.
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Affiliation(s)
- Kazuhiko Nishida
- Graduate School of Frontier Biosciences, Osaka University, Yamadaoka 1-3, Suita, Osaka 565-0871, Japan.
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16
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Hayata T, Blitz IL, Iwata N, Cho KWY. Identification of embryonic pancreatic genes using Xenopus DNA microarrays. Dev Dyn 2009; 238:1455-66. [PMID: 19191222 DOI: 10.1002/dvdy.21868] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The pancreas is both an exocrine and endocrine endodermal organ involved in digestion and glucose homeostasis. During embryogenesis, the anlagen of the pancreas arise from dorsal and ventral evaginations of the foregut that later fuse to form a single organ. To better understand the molecular genetics of early pancreas development, we sought to isolate markers that are uniquely expressed in this tissue. Microarray analysis was performed comparing dissected pancreatic buds, liver buds, and the stomach region of tadpole stage Xenopus embryos. A total of 912 genes were found to be differentially expressed between these organs during early stages of organogenesis. K-means clustering analysis predicted 120 of these genes to be specifically enriched in the pancreas. Of these, we report on the novel expression patterns of 24 genes. Our analyses implicate the involvement of previously unsuspected signaling pathways during early pancreas development. Developmental Dynamics 238:1455-1466, 2009. (c) 2009 Wiley-Liss, Inc.
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Affiliation(s)
- Tadayoshi Hayata
- Department of Developmental and Cell Biology, University of California, Irvine, California, USA
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17
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Ristola M, Arpiainen S, Saleem MA, Mathieson PW, Welsh GI, Lehtonen S, Holthöfer H. Regulation of Neph3 gene in podocytes--key roles of transcription factors NF-kappaB and Sp1. BMC Mol Biol 2009; 10:83. [PMID: 19703278 PMCID: PMC2736951 DOI: 10.1186/1471-2199-10-83] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2008] [Accepted: 08/24/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Neph3 (filtrin) is expressed in the glomerular podocytes where it localizes at the specialized cell adhesion structures of the foot processes called slit diaphragms which form the outermost layer of the glomerular filtration barrier. Neph3 protein shows homology and structural similarity to Neph1, Neph2 and nephrin, which all are crucial for maintaining the normal glomerular ultrafiltration function. The exact function of Neph3 in the kidney is not known but we have previously shown that the level of Neph3 mRNA is decreased in proteinuric diseases. This suggests that Neph3 may play a role in the pathogenesis of kidney damage, and emphasizes the need to analyze the regulatory mechanisms of Neph3 gene. In this study we investigated the transcriptional regulation of Neph3 gene by identifying transcription factors that control Neph3 expression. RESULTS We cloned and characterized approximately 5 kb fragment upstream of the Neph3 gene. Neph3 proximal promoter near the transcription start site was found to be devoid of TATA and CAAT boxes, but to contain a highly GC-rich area. Using promoter reporter gene constructs, we localized the main activating regulatory region of Neph3 gene in its proximal promoter region from -105 to -57. Within this region, putative transcription factor binding sites for NF-kappaB and Sp1 were found by computational analysis. Mutational screening indicated that NF-kappaB and Sp1 response elements are essential for the basal transcriptional activity of the Neph3 promoter. Co-transfection studies further showed that NF-kappaB and Sp1 regulate Neph3 promoter activity. In addition, overexpression of NF-kappaB increased endogenous Neph3 gene expression. Chromatin immunoprecipitation assay using cultured human podocytes demonstrated that both NF-kappaB and Sp1 interact with the Neph3 promoter. CONCLUSION Our results show that NF-kappaB and Sp1 are key regulators of Neph3 expression at the basal level in podocytes, therefore providing new insight into the molecular mechanisms that contribute to the expression of Neph3 gene.
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Affiliation(s)
- Mervi Ristola
- Department of Bacteriology and Immunology, Haartman Institute, P,O, Box 21, 00014 University of Helsinki, Finland.
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18
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Srinivas BP, Woo J, Leong WY, Roy S. A conserved molecular pathway mediates myoblast fusion in insects and vertebrates. Nat Genet 2007; 39:781-6. [PMID: 17529975 DOI: 10.1038/ng2055] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2006] [Accepted: 04/27/2007] [Indexed: 01/31/2023]
Abstract
Skeletal muscles arise by fusion of precursor cells, myoblasts, into multinucleated fibers. In vertebrates, mechanisms controlling this essential step in myogenesis remain poorly understood. Here we provide evidence that Kirrel, a homolog of receptor proteins that organize myoblast fusion in Drosophila melanogaster, is necessary for muscle precursor fusion in zebrafish. Within developing somites, Kirrel expression localized to membranes of fusion-competent myoblasts of the fast-twitch lineage. Unlike wild-type myoblasts that form spatially arrayed syncytial (multinucleated) fast myofibers, those deficient in Kirrel showed a significant reduction in fusion capacity. Inhibition of Rac, a GTPase and the most downstream intracellular transducer of the fusion signal in D. melanogaster, also compromised fast-muscle precursor fusion in zebrafish. However, unlike in D. melanogaster, constitutive Rac activation in zebrafish led to hyperfused giant syncytia, highlighting an entirely new function for this protein in zebrafish for gating the number and polarity of fusion events. These findings uncover a substantial degree of evolutionary conservation in the genetic regulation of myoblast fusion.
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Affiliation(s)
- Bhylahalli P Srinivas
- Institute of Molecular and Cell Biology, Proteos, 61 Biopolis Drive, Singapore 138673
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19
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Rinta-Valkama J, Aaltonen P, Lassila M, Palmén T, Tossavainen P, Knip M, Holthöfer H. Densin and filtrin in the pancreas and in the kidney, targets for humoral autoimmunity in patients with type 1 diabetes. Diabetes Metab Res Rev 2007; 23:119-26. [PMID: 16741999 DOI: 10.1002/dmrr.655] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND AIM The development of autoantibodies against antigens of the pancreatic islet cells is a typical phenomenon in patients with type 1 diabetes. The expression of densin, recently shown to be present in kidney podocytes, was explored in the pancreas. Additionally, we studied whether densin and filtrin, another molecule shared between the kidney podocytes and pancreatic islet cells, can act as autoantigens and whether autoantibodies against these can be detected in patients with type 1 diabetes. METHODS Expression of pancreatic densin was studied with reverse transcription polymerase chain reaction (RT-PCR) and immunofluorescence. Children and adolescents (n = 66) with type 1 diabetes and control subjects were analysed for densin autoantibodies (DAA) and filtrin autoantibodies (FAA) using radioimmunoprecipitation assay. The serum samples were obtained at the time of diagnosis and after a duration of 2, 5 and 10 years. RESULTS Densin expression was observed in the pancreas, localising to the beta cells. DAA were detected in 33% of the patients and the positivity was typically seen already at diagnosis. FAA were observed in 11% of the patients. The proportion of islet cell antibody (ICA) positive, GADA positive and protein tyrosine phosphatase-related islet antigen 2 antibody (IA-2A)-positive patients decreased during the follow-up period, and a similar trend was seen for DAA but not for FAA. Among the 14 patients with signs of renal injury, four tested positive for DAA and two for FAA. CONCLUSIONS Densin is a novel molecule shared by the kidney glomerular podocytes and pancreatic islet cells. Densin and filtrin can act as autoantigens, and autoantibodies against these can be detected in patients with type 1 diabetes.
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Affiliation(s)
- Johanna Rinta-Valkama
- Biomedicum Helsinki, Department of Bacteriology and Immunology, University of Helsinki, Finland
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20
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Mann CJ, Hinits Y, Hughes SM. Comparison of neurolin (ALCAM) and neurolin-like cell adhesion molecule (NLCAM) expression in zebrafish. Gene Expr Patterns 2006; 6:952-63. [PMID: 16750657 DOI: 10.1016/j.modgep.2006.03.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2006] [Revised: 03/19/2006] [Accepted: 03/24/2006] [Indexed: 11/24/2022]
Abstract
Many immunoglobulin (Ig)-superfamily cell adhesion molecules influence skeletal muscle formation. In Drosophila, dumbfounded (duf/kirre), irreC, sticks and stones and hibris encode related Ig-family proteins expressed in subsets of neurons and muscle precursor cells. The family mediates cell migration, axon guidance and fusion of myoblasts. Despite the importance of these genes in invertebrate myogenesis, no obvious functional parallels are known in vertebrate myogenesis. Here we investigate the gene expression pattern and phylogenetic and protein-structural relationships of the duf-related molecules neurolin and neurolin-like cell adhesion molecule (NLCAM), members of the activated leukocyte cell adhesion molecule (ALCAM) sub-family of Ig-molecules. These proteins are among the closest to Duf/Kirre by sequence. During zebrafish development, neurolin is expressed in subsets of somite and muscle cells, heart and numerous sites of neuronal maturation. The new ALCAM-family member, NLCAM, appears to have arisen by duplication of neurolin/ALCAM. NLCAM is expressed widely during gastrulation, particularly in the nascent neural plate, but later becomes predominantly expressed in sites of muscle and nerve maturation and in the fin fold. The expression of each gene is often in groups of cells in similar parts of the embryo; for example, in the region of Rohon Beard neurons, trigeminal ganglion and fusing fast and migrating slow muscle fibres. However, expression can also be distinct and dynamic; for example, muscle pioneer fibres express neurolin but not NLCAM at high level. Both molecules are expressed in subsets of muscle precursors at times prior to fusion.
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Affiliation(s)
- Christopher J Mann
- MRC Centre for Developmental Neurobiology and Randall Division of Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, London SE1 1UL, UK
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21
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Rinta-Valkama J, Palmén T, Lassila M, Holthöfer H. Podocyte-associated proteins FAT, alpha-actinin-4 and filtrin are expressed in Langerhans islets of the pancreas. Mol Cell Biochem 2006; 294:117-25. [PMID: 16841182 DOI: 10.1007/s11010-006-9251-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Accepted: 06/01/2006] [Indexed: 02/02/2023]
Abstract
Nephrin is a crucial podocyte molecule in the kidney glomerular filtration barrier and it is also expressed in Langerhans islet beta cells of the pancreas. Recently, genetic mapping of proteinuric kidney disease genes and animal models have revealed further important molecules for the kidney filtration function including alpha-actinin-4, podocin, FAT, and NEPH1. This study was addressed to explore the pancreatic expression of the podocyte molecules podocin, FAT, alpha-actinin-4, NEPH1, NEPH2, filtrin/NEPH3, synaptopodin and CD2 associated protein (CD2AP). The mRNA and protein expressions were studied by RT-PCR and immunoblotting, and localization in the pancreas was investigated by immunofluorescence. Of the nephrin-associated podocyte proteins, filtrin/NEPH3, FAT, and alpha-actinin-4 were found to be expressed in the pancreas at the gene and protein level and localized to Langerhans islets. Immunoreactivity with the podocin antibody was detected mostly in the exocrine pancreas. NEPH1 and synaptopodin expression was detected only at the mRNA level. Further studies are needed to unravel the functional role of these podocyte-associated molecules in the pancreatic Langerhans islets.
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Affiliation(s)
- Johanna Rinta-Valkama
- Research Program in Molecular Medicine, Biomedicum Helsinki, Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, PB 63, 00014, Helsinki, Finland
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22
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Holland AM, Góñez LJ, Naselli G, Macdonald RJ, Harrison LC. Conditional expression demonstrates the role of the homeodomain transcription factor Pdx1 in maintenance and regeneration of beta-cells in the adult pancreas. Diabetes 2005; 54:2586-95. [PMID: 16123346 DOI: 10.2337/diabetes.54.9.2586] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The homeodomain transcription factor Pdx1 is essential for pancreas development. To investigate the role of Pdx1 in the adult pancreas, we employed a mouse model in which transcription of Pdx1 could be reversibly repressed by administration of doxycycline. Repression of Pdx1 in adult mice impaired expression of insulin and glucagon, leading to diabetes within 14 days. Pdx1 repression was associated with increased cell proliferation predominantly in the exocrine pancreas and upregulation of genes implicated in pancreas regeneration. Following withdrawal of doxycycline and derepression of Pdx1, normoglycemia was restored within 28 days; during this period, Pdx1(+)/Ins(+) and Pdx(+)/Ins(-) cells were observed in association with the duct epithelia. These findings confirm that Pdx1 is required for beta-cell function in the adult pancreas and indicate that in the absence of Pdx1 expression, a regenerative program is initiated with the potential for Pdx1-dependent beta-cell neogenesis.
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Affiliation(s)
- Andrew M Holland
- Autoimmunity and Transplantation Division, Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3050, Australia
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23
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Gerke P, Sellin L, Kretz O, Petraschka D, Zentgraf H, Benzing T, Walz G. NEPH2 Is Located at the Glomerular Slit Diaphragm, Interacts with Nephrin and Is Cleaved from Podocytes by Metalloproteinases. J Am Soc Nephrol 2005; 16:1693-702. [PMID: 15843475 DOI: 10.1681/asn.2004060439] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The NEPH family comprises three transmembrane proteins of the Ig superfamily interacting with the glomerular slit diaphragm proteins podocin and ZO-1. NEPH1 binds to nephrin, another component of the slit diaphragm, and loss of either partner causes heavy proteinuria. NEPH2, which is strongly conserved among a large number of species, is also expressed in the kidney; however, its function is unknown. The authors raised NEPH2 antisera to demonstrate NEPH2 expression in a variety of mouse tissues, including the kidney and a podocyte cell line. The authors localized the expression of NEPH2 to the glomerular slit diaphragm by electron microscopy and show NEPH2 homodimerization and specific interactions with the extracellular domain of nephrin in vitro and in vivo. NEPH1, however, failed to interact with NEPH2. The authors detected immunoreactive NEPH2 in urine of healthy subjects, suggesting that the extracellular domain is cleaved under physiologic conditions. These findings were confirmed in vitro in podocyte cell culture. Shedding is increased by tyrosine phosphatase inhibitors and diminished by GM6001, an inhibitor of metalloproteinases. Overexpression experiments indicate an involvement of the MT1-matrix metalloproteinase. The results suggest a role for NEPH2 in the organization and/or maintenance of the glomerular slit diaphragm that may differ from the functions of NEPH1 and nephrin.
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Affiliation(s)
- Peter Gerke
- Renal Division, University Hospital Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
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24
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Kuusniemi AM, Kestilä M, Patrakka J, Lahdenkari AT, Ruotsalainen V, Holmberg C, Karikoski R, Salonen R, Tryggvason K, Jalanko H. Tissue expression of nephrin in human and pig. Pediatr Res 2004; 55:774-81. [PMID: 14764915 DOI: 10.1203/01.pdr.0000117842.10241.2c] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Nephrin is a major component of the glomerular filtration barrier. Mutations in the nephrin gene (NPHS1) are responsible for congenital nephrotic syndrome of the Finnish type (NPHS1). Nephrin was at first thought to be podocyte specific, but recent studies have suggested that nephrin is also expressed in nonrenal tissues such as pancreas and CNS. We studied the expression of nephrin in human and porcine tissues at different stages of development and correlated these findings to clinical characteristics of NPHS1 children. Immunofluorescence staining and Western blotting were used to detect nephrin protein in frozen tissue samples. Polyclonal antibodies against the intracellular part of nephrin were used in these analyses. In situ hybridization was used to detect nephrin mRNA in specimens from normal human subjects and patients with NPHS1. Nephrin protein was not detected in nonrenal tissues obtained from human and porcine fetuses, newborns, and infants. Likewise, nephrin mRNA expression was not observed outside kidney glomerulus in normal or NPHS1 children. The phenotype analysis of NPHS1 children with severe nephrin gene mutations supported the findings in the tissue expression studies and revealed no impairment of the neurologic, testicular, or pancreatic function in a great majority of the patients. The studies suggest that nephrin has no major clinical significance outside the kidney.
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Affiliation(s)
- Arvi-Matti Kuusniemi
- Hospital for Children and Adolescents and Biomedicum Helsinki, University of Helsinki, 00290 Helsinki, Finland
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25
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Ostendorp R, Frisch C, Urban M. Generation, Engineering and Production of Human Antibodies Using Hucal®. Antibodies (Basel) 2004. [DOI: 10.1007/978-1-4419-8877-5_2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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