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Sachs W, Blume L, Loreth D, Schebsdat L, Hatje F, Koehler S, Wedekind U, Sachs M, Zieliniski S, Brand J, Conze C, Florea BI, Heppner F, Krüger E, Rinschen MM, Kretz O, Thünauer R, Meyer-Schwesinger C. The proteasome modulates endocytosis specifically in glomerular cells to promote kidney filtration. Nat Commun 2024; 15:1897. [PMID: 38429282 PMCID: PMC10907641 DOI: 10.1038/s41467-024-46273-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 02/16/2024] [Indexed: 03/03/2024] Open
Abstract
Kidney filtration is ensured by the interaction of podocytes, endothelial and mesangial cells. Immunoglobulin accumulation at the filtration barrier is pathognomonic for glomerular injury. The mechanisms that regulate filter permeability are unknown. Here, we identify a pivotal role for the proteasome in a specific cell type. Combining genetic and inhibitor-based human, pig, mouse, and Drosophila models we demonstrate that the proteasome maintains filtration barrier integrity, with podocytes requiring the constitutive and glomerular endothelial cells the immunoproteasomal activity. Endothelial immunoproteasome deficiency as well as proteasome inhibition disrupt the filtration barrier in mice, resulting in pathologic immunoglobulin deposition. Mechanistically, we observe reduced endocytic activity, which leads to altered membrane recycling and endocytic receptor turnover. This work expands the concept of the (immuno)proteasome as a control protease orchestrating protein degradation and antigen presentation and endocytosis, providing new therapeutic targets to treat disease-associated glomerular protein accumulations.
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Affiliation(s)
- Wiebke Sachs
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Hamburg Center of Kidney Health, Hamburg, Germany
| | - Lukas Blume
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Hamburg Center of Kidney Health, Hamburg, Germany
| | - Desiree Loreth
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Hamburg Center of Kidney Health, Hamburg, Germany
| | - Lisa Schebsdat
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Hamburg Center of Kidney Health, Hamburg, Germany
| | - Favian Hatje
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Hamburg Center of Kidney Health, Hamburg, Germany
| | - Sybille Koehler
- Hamburg Center of Kidney Health, Hamburg, Germany
- Nephrology, III Medical Clinic, Department of Internal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Uta Wedekind
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Hamburg Center of Kidney Health, Hamburg, Germany
| | - Marlies Sachs
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Hamburg Center of Kidney Health, Hamburg, Germany
| | - Stephanie Zieliniski
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Hamburg Center of Kidney Health, Hamburg, Germany
| | - Johannes Brand
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Hamburg Center of Kidney Health, Hamburg, Germany
| | | | - Bogdan I Florea
- Bio-Organic Synthesis Group, Leiden University, Leiden, The Netherlands
| | - Frank Heppner
- Institute of Neuropathology, Charité, Berlin, Germany
| | - Elke Krüger
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, Greifswald, Germany
| | - Markus M Rinschen
- Hamburg Center of Kidney Health, Hamburg, Germany
- Nephrology, III Medical Clinic, Department of Internal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Oliver Kretz
- Hamburg Center of Kidney Health, Hamburg, Germany
- Nephrology, III Medical Clinic, Department of Internal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Roland Thünauer
- Leibniz Institute of Virology, Hamburg, Germany
- Technology Platform Light Microscopy (TPLM), University Hamburg, Hamburg, Germany
- Advanced Light and Fluorescence Microscopy (ALFM) Facility at the Centre for Structural Systems Biology (CSSB), Hamburg, Germany
| | - Catherine Meyer-Schwesinger
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
- Hamburg Center of Kidney Health, Hamburg, Germany.
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Ma S, Qiu Y, Zhang C. Cytoskeleton Rearrangement in Podocytopathies: An Update. Int J Mol Sci 2024; 25:647. [PMID: 38203817 PMCID: PMC10779434 DOI: 10.3390/ijms25010647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 12/14/2023] [Accepted: 01/01/2024] [Indexed: 01/12/2024] Open
Abstract
Podocyte injury can disrupt the glomerular filtration barrier (GFB), leading to podocytopathies that emphasize podocytes as the glomerulus's key organizer. The coordinated cytoskeleton is essential for supporting the elegant structure and complete functions of podocytes. Therefore, cytoskeleton rearrangement is closely related to the pathogenesis of podocytopathies. In podocytopathies, the rearrangement of the cytoskeleton refers to significant alterations in a string of slit diaphragm (SD) and focal adhesion proteins such as the signaling node nephrin, calcium influx via transient receptor potential channel 6 (TRPC6), and regulation of the Rho family, eventually leading to the disorganization of the original cytoskeletal architecture. Thus, it is imperative to focus on these proteins and signaling pathways to probe the cytoskeleton rearrangement in podocytopathies. In this review, we describe podocytopathies and the podocyte cytoskeleton, then discuss the molecular mechanisms involved in cytoskeleton rearrangement in podocytopathies and summarize the effects of currently existing drugs on regulating the podocyte cytoskeleton.
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Affiliation(s)
| | | | - Chun Zhang
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; (S.M.); (Y.Q.)
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Reichelt J, Sachs W, Frömbling S, Fehlert J, Studencka-Turski M, Betz A, Loreth D, Blume L, Witt S, Pohl S, Brand J, Czesla M, Knop J, Florea BI, Zielinski S, Sachs M, Hoxha E, Hermans-Borgmeyer I, Zahner G, Wiech T, Krüger E, Meyer-Schwesinger C. Non-functional ubiquitin C-terminal hydrolase L1 drives podocyte injury through impairing proteasomes in autoimmune glomerulonephritis. Nat Commun 2023; 14:2114. [PMID: 37055432 PMCID: PMC10102022 DOI: 10.1038/s41467-023-37836-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 04/03/2023] [Indexed: 04/15/2023] Open
Abstract
Little is known about the mechanistic significance of the ubiquitin proteasome system (UPS) in a kidney autoimmune environment. In membranous nephropathy (MN), autoantibodies target podocytes of the glomerular filter resulting in proteinuria. Converging biochemical, structural, mouse pathomechanistic, and clinical information we report that the deubiquitinase Ubiquitin C-terminal hydrolase L1 (UCH-L1) is induced by oxidative stress in podocytes and is directly involved in proteasome substrate accumulation. Mechanistically, this toxic gain-of-function is mediated by non-functional UCH-L1, which interacts with and thereby impairs proteasomes. In experimental MN, UCH-L1 becomes non-functional and MN patients with poor outcome exhibit autoantibodies with preferential reactivity to non-functional UCH-L1. Podocyte-specific deletion of UCH-L1 protects from experimental MN, whereas overexpression of non-functional UCH-L1 impairs podocyte proteostasis and drives injury in mice. In conclusion, the UPS is pathomechanistically linked to podocyte disease by aberrant proteasomal interactions of non-functional UCH-L1.
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Affiliation(s)
- Julia Reichelt
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Wiebke Sachs
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sarah Frömbling
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Julia Fehlert
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Maja Studencka-Turski
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, Hamburg, Germany
| | - Anna Betz
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Desiree Loreth
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Lukas Blume
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Susanne Witt
- Protein production Core Facility, Centre for Structural Systems Biology, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - Sandra Pohl
- Skeletal Pathobiochemistry, Department of Osteology and Biomechanics, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Johannes Brand
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Maire Czesla
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jan Knop
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Bogdan I Florea
- Bio-organic synthesis group, Leiden University, Leiden, The Netherlands
| | - Stephanie Zielinski
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Marlies Sachs
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Elion Hoxha
- III Medical Clinic and Polyclinic, Nephrology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Irm Hermans-Borgmeyer
- Transgenic Animal Service Group, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Gunther Zahner
- III Medical Clinic and Polyclinic, Nephrology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Thorsten Wiech
- Institute of Pathology, Nephropathology Section, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Elke Krüger
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, Hamburg, Germany
| | - Catherine Meyer-Schwesinger
- Institute of Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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Wang X, Zhang N, Li M, Hong T, Meng W, Ouyang T. Ubiquitin C‑terminal hydrolase‑L1: A new cancer marker and therapeutic target with dual effects (Review). Oncol Lett 2023; 25:123. [PMID: 36844618 PMCID: PMC9950345 DOI: 10.3892/ol.2023.13709] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 12/08/2022] [Indexed: 02/11/2023] Open
Abstract
Ubiquitin C-terminal hydrolase-L1 (UCH-L1), a member of the lesser-known deubiquitinating enzyme family, has deubiquitinase and ubiquitin (Ub) ligase activity and the role of stabilizing Ub. UCH-L1 was first discovered in the brain and is associated with regulating cell differentiation, proliferation, transcriptional regulation and numerous other biological processes. UCH-L1 is predominantly expressed in the brain and serves a role in tumor promotion or inhibition. There is still controversy about the effect of UCH-L1 dysregulation in cancer and its mechanisms are unknown. Extensive research to investigate the mechanism of UCH-L1 in different types of cancer is key for the future treatment of UCH-L1-associated cancer. The present review details the molecular structure and function of UCH-L1. The role of UCH-L1 in different types of cancer is also summarized and how novel treatment targets provide a theoretical foundation in cancer research is discussed.
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Affiliation(s)
- Xiaowei Wang
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China,Department of The Second Clinical Medical College of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Na Zhang
- Department of Neurology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Meihua Li
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Tao Hong
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Wei Meng
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China,Correspondence to: Dr Wei Meng or Dr Taohui Ouyang, Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, 17 Yongwai Street, Nanchang, Jiangxi 330006, P.R. China, E-mail:
| | - Taohui Ouyang
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China,Correspondence to: Dr Wei Meng or Dr Taohui Ouyang, Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, 17 Yongwai Street, Nanchang, Jiangxi 330006, P.R. China, E-mail:
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5
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Reinhard L, Machalitza M, Wiech T, Gröne HJ, Lassé M, Rinschen MM, Ferru N, Bräsen JH, Drömann F, Rob PM, Sethi S, Hoxha E, Stahl RA. Netrin G1 Is a Novel Target Antigen in Primary Membranous Nephropathy. J Am Soc Nephrol 2022; 33:1823-1831. [PMID: 35985817 PMCID: PMC9528326 DOI: 10.1681/asn.2022050608] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 06/07/2022] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Primary membranous nephropathy (MN) is caused by circulating autoantibodies binding to antigens on the podocyte surface. PLA2R1 is the main target antigen in 70%-80% of cases, but the pathogenesis is unresolved in 10%-15% of patients. METHODS We used native western blotting to identify IgG4 autoantibodies, which bind an antigen endogenously expressed on podocyte membranes, in the serum of the index patient with MN. These IgG4 autoantibodies were used to immunoprecipitate the target antigen, and mass spectrometry was used to identify Netrin G1 (NTNG1). Using native western blot and ELISA, NTNG1 autoantibodies were analyzed in cohorts of 888 patients with MN or other glomerular diseases. RESULTS NTNG1 was identified as a novel target antigen in MN. It is a membrane protein expressed in healthy podocytes. Immunohistochemistry confirmed granular NTNG1 positivity in subepithelial glomerular immune deposits. In prospective and retrospective MN cohorts, we identified three patients with NTNG1-associated MN who showed IgG4-dominant circulating NTNG1 autoantibodies, enhanced NTNG1 expression in the kidney, and glomerular IgG4 deposits. No NTNG1 autoantibodies were identified in 561 PLA2R1 autoantibodies-positive patients, 27 THSD7A autoantibodies-positive patients, and 77 patients with other glomerular diseases. In two patients with available follow-up of 2 and 4 years, both NTNG1 autoantibodies and proteinuria persisted. CONCLUSIONS NTNG1 expands the repertoire of target antigens in patients with MN. The clinical role of NTNG1 autoantibodies remains to be defined.
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Affiliation(s)
- Linda Reinhard
- III. Department of Medicine, University Medical Center Hamburg–Eppendorf, Hamburg, Germany
| | - Maya Machalitza
- III. Department of Medicine, University Medical Center Hamburg–Eppendorf, Hamburg, Germany
| | - Thorsten Wiech
- Institute of Pathology, Nephropathology Section, University Medical Center Hamburg–Eppendorf, Hamburg, Germany
| | - Hermann-Josef Gröne
- Institute of Pathology, Nephropathology Section, University Medical Center Hamburg–Eppendorf, Hamburg, Germany
- Institute of Pharmacology, Phillips University Marburg, Marburg, Germany
| | - Moritz Lassé
- III. Department of Medicine, University Medical Center Hamburg–Eppendorf, Hamburg, Germany
| | - Markus M. Rinschen
- III. Department of Medicine, University Medical Center Hamburg–Eppendorf, Hamburg, Germany
- Department of Biomedicine and Aarhus Institute of Advanced Studies, Aarhus University, Aarhus, Denmark
| | - Nicoletta Ferru
- III. Department of Medicine, University Medical Center Hamburg–Eppendorf, Hamburg, Germany
| | - Jan Hinrich Bräsen
- Institute of Pathology, Nephropathology Section, Hannover Medical School, Hannover, Germany
| | | | | | - Sanjeev Sethi
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Elion Hoxha
- III. Department of Medicine, University Medical Center Hamburg–Eppendorf, Hamburg, Germany
| | - Rolf A.K. Stahl
- III. Department of Medicine, University Medical Center Hamburg–Eppendorf, Hamburg, Germany
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Nieto-Gañán I, Iturrieta-Zuazo I, Rita C, Carrasco-Sayalero Á. Revisiting immunological and clinical aspects of membranous nephropathy. Clin Immunol 2022; 237:108976. [PMID: 35276323 DOI: 10.1016/j.clim.2022.108976] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 02/16/2022] [Accepted: 03/05/2022] [Indexed: 11/29/2022]
Abstract
Idiopathic or primary membranous nephropathy (IMN) is one of the most frequent causes of nephrotic syndrome in adults and the elderly. It is characterized by a thickening of the wall of the glomerular capillaries due to the presence of immune complex deposits. 85% of membranous nephropathy cases are classified as primary or idiopathic (IMN). The rest are of secondary origin (SMN), caused by autoimmune conditions or malignant tumors as lung cancer, colon and melanomas. It is an organ-specific autoimmune disease in which the complement system plays an important role with the formation of the membrane attack complex (MAC; C5b-9), which produces an alteration of the podocyte structure. The antigen responsible for 70-80% of IMN is a podocyte protein called M-type phospholipase A2 receptor (PLA2R). More recently, another podocyte antigen has been identified, the "Thrombospondin type-1 domain-containing 7A" (THSD7A), which is responsible for 10% of the cases of negative IMN for anti- PLA2R.
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Affiliation(s)
- Israel Nieto-Gañán
- Immunology Department, Hospital Universitario Ramón y Cajal, Madrid, Spain.
| | - Ignacio Iturrieta-Zuazo
- Immunology Department, Hospital Universitario Ramón y Cajal, Madrid, Spain; Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Spain
| | - Claudia Rita
- Immunology Department, Hospital Universitario Ramón y Cajal, Madrid, Spain
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Urinary Protein and Peptide Markers in Chronic Kidney Disease. Int J Mol Sci 2021; 22:ijms222212123. [PMID: 34830001 PMCID: PMC8625140 DOI: 10.3390/ijms222212123] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 10/28/2021] [Accepted: 11/03/2021] [Indexed: 12/21/2022] Open
Abstract
Chronic kidney disease (CKD) is a non-specific type of kidney disease that causes a gradual decline in kidney function (from months to years). CKD is a significant risk factor for death, cardiovascular disease, and end-stage renal disease. CKDs of different origins may have the same clinical and laboratory manifestations but different progression rates, which requires early diagnosis to determine. This review focuses on protein/peptide biomarkers of the leading causes of CKD: diabetic nephropathy, IgA nephropathy, lupus nephritis, focal segmental glomerulosclerosis, and membranous nephropathy. Mass spectrometry (MS) approaches provided the most information about urinary peptide and protein contents in different nephropathies. New analytical approaches allow urinary proteomic-peptide profiles to be used as early non-invasive diagnostic tools for specific morphological forms of kidney disease and may become a safe alternative to renal biopsy. MS studies of the key pathogenetic mechanisms of renal disease progression may also contribute to developing new approaches for targeted therapy.
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Differential Expression of Urinary Exosomal Small RNAs in Idiopathic Membranous Nephropathy. BIOMED RESEARCH INTERNATIONAL 2021; 2020:3170927. [PMID: 33457405 PMCID: PMC7785370 DOI: 10.1155/2020/3170927] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 12/02/2020] [Accepted: 12/13/2020] [Indexed: 11/18/2022]
Abstract
Background Idiopathic membranous nephropathy (IMN) is a major cause of adult nephrotic syndromes, and reliable noninvasive biomarkers for diagnosis and monitoring are urgently needed. In this study, we performed small RNA (sRNA) sequencing to explore sRNA profiles of urinary exosomes derived from IMN patients and healthy controls (CON) to provide clues for identifying novel noninvasive sRNA biomarkers for IMN. Methods Urine samples were collected from five healthy controls and six patients with IMN. High-throughput sequencing was used to screen sRNA expression profiles of urinary exosomes from patients with IMN in two independent cohorts. Results Urinary exosomes were successfully isolated and used to obtain exosomal sRNAs. We screened 131 differentially expressed miRNAs, including 28 specifically expressed miRNAs, then explored the top 10 specifically expressed miRNAs in all IMN individuals. The specifically expressed miRNAs and differentially expressed miRNAs provide potential biomarkers for IMN. Additionally, we discovered numerous sRNAs derived from genomic repetitive sequences, which could represent an exciting new area of research. Conclusion Herein, we revealed significant differences in expression profiles of urinary exosomal miRNAs and repetitive region-derived sRNAs between patients with IMN and healthy controls. The findings could facilitate the development of potential molecular targets for membranous nephropathy.
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Abstract
The lysosome represents an important regulatory platform within numerous vesicle trafficking pathways including the endocytic, phagocytic, and autophagic pathways. Its ability to fuse with endosomes, phagosomes, and autophagosomes enables the lysosome to break down a wide range of both endogenous and exogenous cargo, including macromolecules, certain pathogens, and old or damaged organelles. Due to its center position in an intricate network of trafficking events, the lysosome has emerged as a central signaling node for sensing and orchestrating the cells metabolism and immune response, for inter-organelle and inter-cellular signaling and in membrane repair. This review highlights the current knowledge of general lysosome function and discusses these findings in their implication for renal glomerular cell types in health and disease including the involvement of glomerular cells in lysosomal storage diseases and the role of lysosomes in nongenetic glomerular injuries.
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Mühlig AK, Keir LS, Abt JC, Heidelbach HS, Horton R, Welsh GI, Meyer-Schwesinger C, Licht C, Coward RJ, Fester L, Saleem MA, Oh J. Podocytes Produce and Secrete Functional Complement C3 and Complement Factor H. Front Immunol 2020; 11:1833. [PMID: 32922395 PMCID: PMC7457071 DOI: 10.3389/fimmu.2020.01833] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 07/08/2020] [Indexed: 12/20/2022] Open
Abstract
Podocytes are an important part of the glomerular filtration barrier and the key player in the development of proteinuria, which is an early feature of complement mediated renal diseases. Complement factors are mainly liver-born and present in circulation. Nevertheless, there is a growing body of evidence for additional sites of complement protein synthesis, including various cell types in the kidney. We hypothesized that podocytes are able to produce complement components and contribute to the local balance of complement activation and regulation. To investigate the relevant balance between inhibiting and activating sides, our studies focused on complement factor H (CFH), an important complement regulator, and on C3, the early key component for complement activation. We characterized human cultured podocytes for the expression and secretion of activating and regulating complement factors, and analyzed the secretion pathway and functional activity. We studied glomerular CFH and C3 expression in puromycin aminonucleoside (PAN) -treated rats, a model for proteinuria, and the physiological mRNA-expression of both factors in murine kidneys. We found, that C3 and CFH were expressed in cultured podocytes and expression levels differed from those in cultivated glomerular endothelial cells. The process of secretion in podocytes was stimulated with interferon gamma and located in the Golgi apparatus. Cultured podocytes could initiate the complement cascade by the splitting of C3, which can be shown by the generation of C3a, a functional C3 split product. C3 contributed to external complement activation. Podocyte-secreted CFH, in conjunction with factor I, was able to split C3b. Podocytes derived from a patient with a CFH mutation displayed impaired cell surface complement regulation. CFH and C3 were synthesized in podocytes of healthy C57Bl/6-mice and were upregulated in podocytes of PAN treated rats. These data show that podocytes produce functionally active complement components, and could therefore influence the local glomerular complement activation and regulation. This modulating effect should therefore be considered in all diseases where glomerular complement activation occurs. Furthermore, our data indicate a potential novel role of podocytes in the innate immune system.
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Affiliation(s)
- Anne K. Mühlig
- University Children's Research@Kinder-UKE, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Department of Pediatric Nephrology, University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Lindsay S. Keir
- Bristol Renal and Children's Renal Unit, University of Bristol, Bristol, United Kingdom
| | - Jana C. Abt
- Department of Pediatric Nephrology, University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Hannah S. Heidelbach
- Department of Pediatric Nephrology, University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Rachel Horton
- Bristol Renal and Children's Renal Unit, University of Bristol, Bristol, United Kingdom
| | - Gavin I. Welsh
- Bristol Renal and Children's Renal Unit, University of Bristol, Bristol, United Kingdom
| | - Catherine Meyer-Schwesinger
- Center of Experimental Medicine, Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christoph Licht
- Division of Pediatric Nephrology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Richard J. Coward
- Bristol Renal and Children's Renal Unit, University of Bristol, Bristol, United Kingdom
| | - Lars Fester
- Department of Neuroanatomy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Institute for Anatomy and Cell Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Moin A. Saleem
- Bristol Renal and Children's Renal Unit, University of Bristol, Bristol, United Kingdom
| | - Jun Oh
- University Children's Research@Kinder-UKE, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Department of Pediatric Nephrology, University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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11
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Fang Y, Li F, Qi C, Mao X, Xu Y, Zhao Z, Wu H, Zhang Z. Plakoglobin is involved in cytoskeletal rearrangement of podocytes under the regulation of UCH-L1. Biochem Biophys Res Commun 2020; 529:112-118. [PMID: 32560811 DOI: 10.1016/j.bbrc.2020.05.093] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 05/14/2020] [Indexed: 11/25/2022]
Abstract
UCH-L1 is a de-ubiquitination enzyme comprehensively distributed in neural cells and podocytes, which is involved in several kinds of nervous system and kidney related diseases. Our previous studies have demonstrated the aberrant up-regulation of UCH-L1 in podocytes of renal diseases, but how dose podocytes are injured by up-regulated UCH-L1 is waiting to be elucidated. Here, we observed the cytoskeleton rearrangement in podocytes with over-expression of UCH-L1, accompanied with a down-regulation of synaptopodin and RhoA, which are closely related to cytoskeletal stabilization. However, we did not see any alteration of RhoA ubiquitination level under the stimulation of UCH-L1 in podocytes. Subsequently, mass spectrum was applied in UCH-L1-flag immunoprecipitation and plakoglobin was screened out, which was among the UCH-L1-combined proteins and most likely related to cytoskeleton rearrangement. Our experiment demonstrates UCH-L1 may not injure podocytes cytoskeleton through a direct regulation on RhoA/Synaptopodin, but through the regulation of plakoglobin, which could be a promising target for treatment of renal disease in the future.
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Affiliation(s)
- Yili Fang
- Department of Pathology, Shanghai Medical College, Fudan University, Shanghai, 200032, PR China
| | - Fang Li
- Department of Pathology, Shanghai Medical College, Fudan University, Shanghai, 200032, PR China
| | - Chenyang Qi
- Department of Pathology, Shanghai Medical College, Fudan University, Shanghai, 200032, PR China
| | - Xing Mao
- Department of Pathology, Shanghai Medical College, Fudan University, Shanghai, 200032, PR China
| | - Yuyin Xu
- Department of Pathology, Shanghai Medical College, Fudan University, Shanghai, 200032, PR China
| | - Zhonghua Zhao
- Department of Pathology, Shanghai Medical College, Fudan University, Shanghai, 200032, PR China
| | - Huijuan Wu
- Department of Pathology, Shanghai Medical College, Fudan University, Shanghai, 200032, PR China.
| | - Zhigang Zhang
- Department of Pathology, Shanghai Medical College, Fudan University, Shanghai, 200032, PR China.
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Sun L, Zou LX, Han YC, Zhu DD, Chen T, Wang J. Role of A20/TNFAIP3 deficiency in lupus nephritis in MRL/lpr mice. Clin Exp Nephrol 2019; 24:107-118. [PMID: 31811410 DOI: 10.1007/s10157-019-01826-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 11/20/2019] [Indexed: 10/25/2022]
Abstract
BACKGROUND The activation of the nuclear factor-κB (NF-κB) signaling pathway gives rise to inflammation in the pathogenesis of lupus nephritis (LN), with A20 serving as a negative feedback regulator and ubiquitin C‑terminal hydrolase L1 (UCH-L1) acting as a downstream target protein. However, their roles in the mechanism of LN remain undetermined. METHODS In the present study, the expression of A20 and UCH-L1, the activity of NF-κB and ubiquitin-proteasome system (UPS) were measured in MRL/lpr mice and A20 gene silenced podocytes. The severity of podocyte injury and immune complex deposits were detected by transmission electron microscopy. RESULTS The in vivo experiments revealed that A20 failed to terminate the activation of NF-κB, which was accompanied by UCH-L1 overexpression, ubiquitin accumulation, and glomerular injury in LN mice. Immunosuppression therapy did improve LN progression by attenuating A20 deficiency. In vitro experiments confirmed that tumor necrosis factor-α induced NF-κB activation, which led to UCH-L1 overexpression, UPS impairment, the upregulation of desmin and the downregulation of synaptopodin in A20 gene silenced podocytes. CONCLUSION Thus, the results of the present study suggest that A20 regulates UCH-L1 expression via the NF-κB signaling pathway and A20 deficiency might play an important role in LN pathogenesis. Therefore, the A20 protein may serve as a promising therapeutic target for LN.
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Affiliation(s)
- Ling Sun
- Department of Nephrology, Xuzhou Central Hospital, Medical College of Southeast University, Xuzhou, Jiangsu, People's Republic of China.
| | - Lu-Xi Zou
- Zhejiang University, Hangzhou, Zhejiang, People's Republic of China.
| | - Yu-Chen Han
- Institute of Nephrology, Zhongda Hospital, Medical College of Southeast University, Jiangsu, People's Republic of China
| | - Dong-Dong Zhu
- Institute of Nephrology, Zhongda Hospital, Medical College of Southeast University, Jiangsu, People's Republic of China
| | - Ting Chen
- Department of Nephrology, Xuzhou Central Hospital, Medical College of Southeast University, Xuzhou, Jiangsu, People's Republic of China
| | - Jie Wang
- Department of Pathology, Xuzhou Central Hospital, Medical College of Southeast University, Xuzhou, Jiangsu, People's Republic of China
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Molecular stratification of idiopathic nephrotic syndrome. Nat Rev Nephrol 2019; 15:750-765. [DOI: 10.1038/s41581-019-0217-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2019] [Indexed: 01/03/2023]
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Xu Y, Gao H, Hu Y, Fang Y, Qi C, Huang J, Cai X, Wu H, Ding X, Zhang Z. High glucose-induced apoptosis and necroptosis in podocytes is regulated by UCHL1 via RIPK1/RIPK3 pathway. Exp Cell Res 2019; 382:111463. [PMID: 31247189 DOI: 10.1016/j.yexcr.2019.06.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/06/2019] [Accepted: 06/10/2019] [Indexed: 02/06/2023]
Abstract
Diabetic nephrology (DN) is attributed largely to the depletion of podocytes, which is closely associated to apoptosis. However, the complex mechanism of podocyte loss in DN pathogenesis remains unclear. Recently, necroptosis has emerged as an important cell death model in many pathological conditions, which is regulated through RIPK1/RIPK3 pathway. In addition, necroptosis was found to share several upstream signaling pathways with apoptosis. Therefore, it was speculated that both apoptosis and necroptosis may occur in podocytes during the process of podocyte injury in DN. Herein, necroptosis and apoptosis were shown to be involved in podocyte injury induced by high glucose (HG), both in vitro and in vivo, with a high level of positive signaling markers RIPK1 (298.4 ± 17.35), cleaved caspase 3 (497.1 ± 23.09), RIPK3 (108.4 ± 14.92), and MLKL (470.4 ± 15.73) than the control groups. Scaning electron microscopy examination revealed the morphological characteristics of necroptotic and apoptotic cells, which differed remarkably. z-VAD-fmk, a pan-inhibitor of apoptosis, could block apoptosis and enhance necroptosis. Furthermore, UCHL1 was found to play a major role in promoting podocyte necroptosis by regulating the ubiquitination state of the RIPK1/RIPK3 pathway. The half-life of RIPK1 and RIPK3 proteins reduced and the expression of RIPK1, RIPK3, and MLKL decreased significantly after the knockdown of UCHL1. It was shown that UCHL1 exerted a more regulatory response to necroptosis. These data suggested that necroptosis may have more effect on the loss of podocytes than apoptosis in DN with the regulation of UCHL1. Thus, inhibiting UCHL1 to downregulate the RIPK1/RIPK3 pathway may be a novel strategy to protect the podocytes in DN patients.
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Affiliation(s)
- Yuyin Xu
- The Department of Pathology, School of Basic Medical Science, Fudan University, China; The Department of Pathology, Fudan University Shanghai Cancer Center, China
| | - Hongyang Gao
- The Department of Pathology, School of Basic Medical Science, Fudan University, China
| | - Yuan Hu
- The Department of Pathology, School of Basic Medical Science, Fudan University, China
| | - Yili Fang
- The Department of Pathology, School of Basic Medical Science, Fudan University, China
| | - Chenyang Qi
- The Department of Pathology, School of Basic Medical Science, Fudan University, China
| | - Jiebo Huang
- The Department of Nephrology, Putuo District Central Hospital, Shanghai, China
| | - Xiaofan Cai
- The Department of Nephrology, Longhua Hospital, Shanghai, China
| | - Huijuan Wu
- The Department of Pathology, School of Basic Medical Science, Fudan University, China
| | - Xiaoqiang Ding
- Shanghai Key Laboratory of Renal Diseases and Blood Purification, Zhongshan Hospital, Fudan University, China
| | - Zhigang Zhang
- The Department of Pathology, School of Basic Medical Science, Fudan University, China; Shanghai Key Laboratory of Renal Diseases and Blood Purification, Zhongshan Hospital, Fudan University, China.
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Tamaki M, Tominaga T, Fujita Y, Koezuka Y, Ichien G, Murakami T, Kishi S, Yamamoto K, Abe H, Nagai K, Doi T. All-trans retinoic acid suppresses bone morphogenetic protein 4 in mouse diabetic nephropathy through a unique retinoic acid response element. Am J Physiol Endocrinol Metab 2019; 316:E418-E431. [PMID: 30601699 DOI: 10.1152/ajpendo.00218.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Diabetic nephropathy (DN) causes mesangial matrix expansion, which results in glomerulosclerosis and renal failure. Collagen IV (COL4) is a major component of the mesangial matrix that is positively regulated by bone morphogenetic protein 4 (BMP4)/suppressor of mothers against decapentaplegic (Smad1) signaling. Because previous studies showed that retinoids treatment had a beneficial effect on kidney disease, we investigated the therapeutic potential of retinoids in DN, focusing especially on the regulatory mechanism of BMP4. Diabetes was induced with streptozotocin in 12-wk-old male Crl:CD1(ICR) mice, and, 1 mo later, we initiated intraperitoneal injection of all-trans retinoic acid (ATRA) three times weekly. Glomerular matrix expansion, which was associated with increased BMP4, phosphorylated Smad1, and COL4 expression, worsened in diabetic mice at 24 wk of age. ATRA administration alleviated DN and downregulated BMP4, phosopho-Smad1, and COL4. In cultured mouse mesangial cells, treatment with ATRA or a retinoic acid receptor-α (RARα) agonist significantly decreased BMP4 and COL4 expression. Genomic analysis suggested two putative retinoic acid response elements (RAREs) for the mouse Bmp4 gene. Chromatin immunoprecipitation analysis and reporter assays indicated a putative RARE of the Bmp4 gene, located 11,488-11,501 bp upstream of exon 1A and bound to RARα and retinoid X receptor (RXR), which suppressed BMP4 expression after ATRA addition. ATRA suppressed BMP4 via binding of a RARα/RXR heterodimer to a unique RARE, alleviating glomerular matrix expansion in diabetic mice. These findings provide a novel regulatory mechanism for treatment of DN.
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Affiliation(s)
- Masanori Tamaki
- Department of Nephrology, Institute of Biomedical Sciences, Tokushima University Graduate School , Tokushima , Japan
| | - Tatsuya Tominaga
- Department of Nephrology, Institute of Biomedical Sciences, Tokushima University Graduate School , Tokushima , Japan
| | - Yui Fujita
- Department of Nephrology, Institute of Biomedical Sciences, Tokushima University Graduate School , Tokushima , Japan
| | | | | | - Taichi Murakami
- Department of Nephrology, Institute of Biomedical Sciences, Tokushima University Graduate School , Tokushima , Japan
| | - Seiji Kishi
- Department of Nephrology, Institute of Biomedical Sciences, Tokushima University Graduate School , Tokushima , Japan
| | | | - Hideharu Abe
- Department of Nephrology, Institute of Biomedical Sciences, Tokushima University Graduate School , Tokushima , Japan
| | - Kojiro Nagai
- Department of Nephrology, Institute of Biomedical Sciences, Tokushima University Graduate School , Tokushima , Japan
| | - Toshio Doi
- Department of Nephrology, Institute of Biomedical Sciences, Tokushima University Graduate School , Tokushima , Japan
- Research Institute for Production Development , Kyoto , Japan
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Membranous Nephropathy and Anti-Podocytes Antibodies: Implications for the Diagnostic Workup and Disease Management. BIOMED RESEARCH INTERNATIONAL 2018; 2018:6281054. [PMID: 29511687 PMCID: PMC5817285 DOI: 10.1155/2018/6281054] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Revised: 08/31/2017] [Accepted: 10/15/2017] [Indexed: 12/11/2022]
Abstract
The discovery of circulating antibodies specific for native podocyte antigens has transformed the diagnostic workup and greatly improved management of idiopathic membranous nephropathy (iMN). In addition, their identification has clearly characterized iMN as a largely autoimmune disorder. Anti-PLA2R1 antibodies are detected in approximately 70% to 80% and anti-THSD7A antibodies in only 2% of adult patients with iMN. The presence of anti-THSD7A antibodies is associated with increased risk of malignancy. The assessment of PLA2R1 and THSD7A antigen expression in glomerular immune deposits has a better sensitivity than measurement of the corresponding autoantibodies. Therefore, in the presence of circulating anti-podocytes autoantibodies and/or enhanced expression of PLA2R1 and THSD7A antigens MN should be considered as primary MN (pMN). Anti-PLA2R1 or anti-THSD7A autoantibodies have been proposed as biomarkers of autoimmune disease activity and their blood levels should be regularly monitored in pMN to evaluate disease activity and predict outcomes. We propose a revised clinical workup flow for patients with MN that recommends assessment of kidney biopsy for PLA2R1 and THSD7A antigen expression, screening for circulating anti-podocytes antibodies, and assessment for secondary causes, especially cancer, in patients with THSD7A antibodies. Persistence of anti-podocyte antibodies for 6 months or their increase in association with nephrotic proteinuria should lead to the introduction of immunosuppressive therapies. Recent data have reported the efficacy and safety of new specific therapies targeting B cells (anti-CD20 antibodies, inhibitors of proteasome) in pMN which should lead to an update of currently outdated treatment guidelines.
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Radón V, Czesla M, Reichelt J, Fehlert J, Hammel A, Rosendahl A, Knop JH, Wiech T, Wenzel UO, Sachs M, Reinicke AT, Stahl RA, Meyer-Schwesinger C. Ubiquitin C-Terminal Hydrolase L1 is required for regulated protein degradation through the ubiquitin proteasome system in kidney. Kidney Int 2018; 93:110-127. [DOI: 10.1016/j.kint.2017.05.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 05/08/2017] [Accepted: 05/11/2017] [Indexed: 11/30/2022]
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Fuchslocher Chico J, Saggau C, Adam D. Proteolytic control of regulated necrosis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:2147-2161. [DOI: 10.1016/j.bbamcr.2017.05.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 05/27/2017] [Accepted: 05/30/2017] [Indexed: 12/20/2022]
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Cybulsky AV. Endoplasmic reticulum stress, the unfolded protein response and autophagy in kidney diseases. Nat Rev Nephrol 2017; 13:681-696. [DOI: 10.1038/nrneph.2017.129] [Citation(s) in RCA: 244] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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21
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Liu WJ, Li ZH, Chen XC, Zhao XL, Zhong Z, Yang C, Wu HL, An N, Li WY, Liu HF. Blockage of the lysosome-dependent autophagic pathway contributes to complement membrane attack complex-induced podocyte injury in idiopathic membranous nephropathy. Sci Rep 2017; 7:8643. [PMID: 28819100 PMCID: PMC5561110 DOI: 10.1038/s41598-017-07889-z] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 07/05/2017] [Indexed: 11/21/2022] Open
Abstract
Dysregulation of autophagy-mediated podocyte homeostasis is proposed to play a role in idiopathic membranous nephropathy (IMN). In the present study, autophagic activity and lysosomal alterations were investigated in podocytes of IMN patients and in cultured podocytes exposed to sublytic terminal complement complex, C5b-9. C5b-9 upregulated the number of LC3 positive puncta and the expression of p62 in patient podocytes and in C5b-9 injuried podocyte model. The lysosomal turnover of LC3-II was not influenced, although the BECN1 expression level was upregulated after exposure of podocytes to C5b-9. C5b-9 also caused a significant increase in the number of autophagosomes but not autolysosomes, suggesting that C5b-9 impairs the lysosomal degration of autophagosomes. Moreover, C5b-9 exacerbated the apoptosis of podocytes, which could be mimicked by chloroquine treatment, indicating that C5b-9 triggered podocyte injury, at least partially through inhibiting autophagy. Subsequent studies revealed that C5b-9 triggered lysosomal membrane permeabilization, which likely caused the decrease in enzymatic activity, defective acidification of lysosomes, and suppression of DQ-ovalbumin degradation. Taken together, our results suggest that the lysosomal-dependent autophagic pathway is blocked by C5b-9, which may play a key role in podocyte injury during the development of IMN.
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Affiliation(s)
- Wei Jing Liu
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China.,Renal Research Institution of Beijing University of Chinese Medicine, and Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing, 100700, China
| | - Zhi-Hang Li
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China
| | - Xiao-Cui Chen
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China
| | - Xiao-Lu Zhao
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China
| | - Zhen Zhong
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China
| | - Chen Yang
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China
| | - Hong-Luan Wu
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China
| | - Ning An
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China
| | - Wei-Yan Li
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China
| | - Hua-Feng Liu
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China.
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Goru SK, Kadakol A, Gaikwad AB. Hidden targets of ubiquitin proteasome system: To prevent diabetic nephropathy. Pharmacol Res 2017; 120:170-179. [PMID: 28363724 DOI: 10.1016/j.phrs.2017.03.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Accepted: 03/21/2017] [Indexed: 12/21/2022]
Abstract
Diabetic nephropathy (DN) is the major cause of end stage renal failure. Although, several therapeutic targets have emerged to prevent the progression of DN, the number of people with DN still continues to rise worldwide, suggesting an urgent need of novel targets to prevent DN completely. Currently, the role of ubiquitin proteasome system (UPS) has been highlighted in the pathogenesis and progression of various diseases like obesity, insulin resistance, atherosclerosis, cancers, neurodegerative disorders and including secondary complications of diabetes. UPS mainly involves in protein homeostatis through ubiquitination (post translational modification) and proteasomal degradation of various proteins. Ubiquitination, not only involves in proteasomal degradation, but also directs the substrate proteins to participate in multitude of cell signalling pathways. However, very little is known about ubiquitination and UPS in the progression of DN. This review mainly focuses on UPS and its components including E2 conjugating enzymes, E3 ligases and deubiquitinases (DUBs) in the development of DN and thus may help us to find novel therapeutic targets with in UPS to prevent DN completely in future.
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Affiliation(s)
- Santosh Kumar Goru
- Laboratory of Molecular Pharmacology, Department of Pharmacy, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan 333031, India
| | - Almesh Kadakol
- Laboratory of Molecular Pharmacology, Department of Pharmacy, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan 333031, India
| | - Anil Bhanudas Gaikwad
- Laboratory of Molecular Pharmacology, Department of Pharmacy, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan 333031, India.
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Cui JH, Xie X. UCH-L1 Expressed by Podocytes: a Potentially Therapeutic Target for Lupus Nephritis? Inflammation 2017; 40:657-665. [DOI: 10.1007/s10753-017-0512-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Sareen-Khanna K, Papillon J, Wing SS, Cybulsky AV. Role of the deubiquitinating enzyme ubiquitin-specific protease-14 in proteostasis in renal cells. Am J Physiol Renal Physiol 2016; 311:F1035-F1046. [DOI: 10.1152/ajprenal.00252.2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 09/07/2016] [Indexed: 01/02/2023] Open
Abstract
Kidney cell injury may be associated with protein misfolding and induction of endoplasmic reticulum (ER) stress. Examples include complement-induced glomerular epithelial cell (GEC)/podocyte injury in membranous nephropathy and ischemia-reperfusion injury. Renal cell injury can also result from mutations in integral proteins, which lead to their misfolding and accumulation. Certain nephrin missense mutants misfold, accumulate in the ER, and induce ER stress. We examined if enhancement of ubiquitin-proteasome system function may facilitate proteostasis and confer protection against injury. Ubiquitin-specific protease 14 (Usp14) is reported to retard proteasomal protein degradation. Thus inhibition of Usp14 may enhance degradation of misfolded proteins and attenuate cell injury. In GEC, the reporter proteins GFPu (a “misfolded” protein) and CD3δ (an ER-associated degradation substrate) undergo time-dependent proteasomal degradation. Complement did not affect degradation of CD3δ-yellow fluorescent protein (YFP), but accelerated degradation of GFPu, and the Usp14-directed inhibitor IU1 further accelerated this degradation. Conversely, overexpression of Usp14 reduced degradation of GFPu and CD3δ-YFP. In 293T cells, IU1 did not enhance degradation of disease-associated nephrin missense mutants I171N and S724C, whereas overexpression of Usp14 reduced degradation. IU1 was cytoprotective after injury induced by the ER stressor tunicamycin and in vitro ischemia-reperfusion, but did not affect complement-induced cytotoxicity. In conclusion, Usp14 controls proteasomal degradation of some misfolded proteins. In addition, a Usp14-directed inhibitor reduces cytotoxicity in the context of global protein misfolding during certain types of renal cell injury.
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Affiliation(s)
- Kapil Sareen-Khanna
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
| | - Joan Papillon
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
| | - Simon S. Wing
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
| | - Andrey V. Cybulsky
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
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Wnt/β-Catenin Signaling Mediated-UCH-L1 Expression in Podocytes of Diabetic Nephropathy. Int J Mol Sci 2016; 17:ijms17091404. [PMID: 27571062 PMCID: PMC5037684 DOI: 10.3390/ijms17091404] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 08/07/2016] [Accepted: 08/18/2016] [Indexed: 02/07/2023] Open
Abstract
Increasing studies identified podocyte injury as a key early risk factor resulting in diabetic nephropathy (DN). The ubiquitin carboxy-terminal hydrolase 1 (UCH-L1) participates in podocyte differentiation and injury, which is elevated in the podocytes of a variety of nephritis. Whether UCH-L1 expression is positively related to podocyte injury of DN remains unclear. In this study, elevated expression of UCH-L1 and its intrinsic mechanism in high glucose (HG)-stimulated murine podocytes were investigated using western blot and real-time quantitative PCR. Kidney biopsies of DN patients and health individuals were stained by immunofluorescence (IF) method. The morphological and functional changes of podocytes were tested by F-actin staining and cell migration assay. Results demonstrated that HG induced upregulation of UCH-L1 and activation of the Wnt/β-catenin signaling pathway in podocytes. However, blocking of the Wnt pathway by dickkopf related protein 1 (DKK1) eliminated the above changes. Furthermore, IF staining confirmed that, compared with healthy individuals, the expression of UCH-L1 and β-catenin were obviously increased in kidney biopsy of DN patients. Overexpression of UCH-L1 remodeled its actin cytoskeleton, increased its cell migration and impacted its important proteins. All the findings manifested that Wnt/β-catenin/UCH-L1 may be a new potential therapy method in the treatment of DN in future.
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26
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Wilson CL, Murphy LB, Leslie J, Kendrick S, French J, Fox CR, Sheerin NS, Fisher A, Robinson JH, Tiniakos DG, Gray DA, Oakley F, Mann DA. Ubiquitin C-terminal hydrolase 1: A novel functional marker for liver myofibroblasts and a therapeutic target in chronic liver disease. J Hepatol 2015; 63:1421-8. [PMID: 26264933 PMCID: PMC4866442 DOI: 10.1016/j.jhep.2015.07.034] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 07/23/2015] [Accepted: 07/24/2015] [Indexed: 01/07/2023]
Abstract
BACKGROUND & AIMS Ubiquitination is a reversible protein modification involved in the major cellular processes that define cell phenotype and behaviour. Ubiquitin modifications are removed by a large family of proteases named deubiquitinases. The role of deubiquitinases in hepatic stellate cell (HSC) activation and their contribution to fibrogenesis are poorly defined. We have identified that the deubiquitinase ubiquitin C-terminal hydrolase 1 (UCHL1) is highly induced following HSC activation, determined its function in activated HSC and its potential as a therapeutic target for fibrosis. METHODS Deubiquitinase expression was determined in day 0 and day 10 HSC. Increased UCHL1 expression was confirmed in human HSC and in an alcoholic liver disease (ALD) patient liver. The importance of UCHL1 in hepatic fibrosis was investigated in CCl4 and bile duct ligation injured mice using a pharmacological inhibitor (LDN 57444). The effects of UCHL1 inhibition on HSC proliferation were confirmed by Western blot and 3H thymidine incorporation. RESULTS Here we report that pharmacological inhibition of UCHL1 blocks progression of established fibrosis in CCl4 injured mice. UCHL1 siRNA knockdown, LDN 57444 treatment, or HSC isolated from UCHL1(-/-) mice show attenuated proliferation in response to the mitogen, platelet-derived growth factor. Additionally, we observed changes in the phosphorylation of the cell cycle regulator retinoblastoma protein (Rb) in the absence of UCHL1 highlighting a potential mechanism for the reduced proliferative response. CONCLUSIONS UCHL1 expression is highly upregulated upon HSC activation and is involved in the regulation of HSC proliferation. This study highlights therapeutic opportunities for pharmacological targeting of UCHL1 in chronic liver disease.
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Affiliation(s)
- Caroline L. Wilson
- Institute of Cellular Medicine, Faculty of Medical Sciences, 4th Floor, William Leech Building, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Lindsay B. Murphy
- Institute of Cellular Medicine, Faculty of Medical Sciences, 4th Floor, William Leech Building, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Jack Leslie
- Institute of Cellular Medicine, Faculty of Medical Sciences, 4th Floor, William Leech Building, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Stuart Kendrick
- Institute of Cellular Medicine, Faculty of Medical Sciences, 4th Floor, William Leech Building, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Jeremy French
- Institute of Cellular Medicine, Faculty of Medical Sciences, 4th Floor, William Leech Building, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Christopher R. Fox
- Institute of Cellular Medicine, Faculty of Medical Sciences, 4th Floor, William Leech Building, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Neil S. Sheerin
- Institute of Cellular Medicine, Faculty of Medical Sciences, 4th Floor, William Leech Building, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Andrew Fisher
- Institute of Cellular Medicine, Faculty of Medical Sciences, 4th Floor, William Leech Building, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - John H. Robinson
- Institute of Cellular Medicine, Faculty of Medical Sciences, 4th Floor, William Leech Building, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Dina G. Tiniakos
- Institute of Cellular Medicine, Faculty of Medical Sciences, 4th Floor, William Leech Building, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Douglas A. Gray
- Ottawa Hospital Research Institute, 501 Smyth Rd, Ottawa K1H 8L6, Canada
| | - Fiona Oakley
- Institute of Cellular Medicine, Faculty of Medical Sciences, 4th Floor, William Leech Building, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Derek A. Mann
- Institute of Cellular Medicine, Faculty of Medical Sciences, 4th Floor, William Leech Building, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK,Corresponding author. Address: Institute of Cellular Medicine, Faculty of Medical Sciences, 4th Floor, William Leech Building, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK. Tel.: +44 191 222 3851, fax: +44 191 222 0723, (D.A. Mann)
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Guo C, Liu Y, Zhao W, Wei S, Zhang X, Wang W, Zeng X. Apelin promotes diabetic nephropathy by inducing podocyte dysfunction via inhibiting proteasome activities. J Cell Mol Med 2015; 19:2273-85. [PMID: 26103809 PMCID: PMC4568931 DOI: 10.1111/jcmm.12619] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 04/15/2015] [Indexed: 12/12/2022] Open
Abstract
Podocyte injuries are associated with progression of diabetic nephropathy (DN). Apelin, an adipocyte-derived peptide, has been reported to be a promoting factor for DN. In this study, we aim to determine whether apelin promotes progression of DN by inducing podocyte dysfunction. kk-Ay mice were used as models for DN. Apelin and its antagonist, F13A were intraperitoneally administered for 4 weeks, respectively. Renal function and foot process proteins were analysed to evaluate the effects of apelin on kk-Ay mice and podocytes. Apelin increased albuminuria and decreased podocyte foot process proteins expression in kk-Ay mice, which is consistent with the results that apelin receptor (APLNR) levels increased in glomeruli of patients or mice with DN. In cultured podocytes, high glucose increased APLNR expression and apelin administration was associated with increased permeability and decreased foot process proteins levels. All these dysfunctions were associated with decreased 26S proteasome activities and increased polyubiquitinated proteins in both kk-Ay mice and cultured podocytes, as demonstrated by 26S proteasome activation with cyclic adenosine monophosphate (cAMP) or oleuropein. These effects seemed to be related to endoplasmic reticulum (ER) stress, as apelin increased C/EBP homologous protein (CHOP) and peiFα levels while cAMP or oleuropein reduced it in high glucose and apelin treated podocytes. These results suggest that apelin induces podocyte dysfunction in DN through ER stress which was induced by decreased proteasome activities in podocytes.
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Affiliation(s)
- Caixia Guo
- Department of Pathophysiology and Pathology, Capital Medical University, Beijing, China.,Department of Cardiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yu Liu
- Department of Pathophysiology and Pathology, Capital Medical University, Beijing, China
| | - Wenjie Zhao
- Department of Pathophysiology and Pathology, Capital Medical University, Beijing, China
| | - Shengnan Wei
- Department of Pathophysiology and Pathology, Capital Medical University, Beijing, China
| | - Xiaoli Zhang
- Department of Pathophysiology and Pathology, Capital Medical University, Beijing, China
| | - Wenying Wang
- Department of Urology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Xiangjun Zeng
- Department of Pathophysiology and Pathology, Capital Medical University, Beijing, China
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ZHANG HONGXIA, MAO XING, SUN YU, HU RUIMIN, LUO WEILI, ZHAO ZHONGHUA, CHEN QI, ZHANG ZHIGANG. NF-κB upregulates ubiquitin C-terminal hydrolase 1 in diseased podocytes in glomerulonephritis. Mol Med Rep 2015; 12:2893-901. [DOI: 10.3892/mmr.2015.3780] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 04/10/2015] [Indexed: 11/05/2022] Open
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Abstract
Complement activation and recruitment of inflammatory leukocytes is an important defense mechanism against bacterial infection. However, complement also can mediate cellular injury and contribute to the pathogenesis of various diseases. With the appreciation that the C5b-9 membrane attack complex can injure cells in the absence of leukocytes, a role for the terminal complement pathway in inducing cell injury and kidney disease was shown in several experimental models, including the rat passive Heymann nephritis model of human membranous nephropathy. In podocytes, sublytic C5b-9 activates a variety of downstream pathways including protein kinases, lipid metabolism, reactive oxygen species, growth factors/gene transcription, endoplasmic reticulum stress, and the ubiquitin-proteasome system, and it impacts the integrity of the cytoskeleton and slit diaphragm proteins. C5b-9 also injures other kidney cells, including mesangial, glomerular endothelial, and tubular epithelial cells, and it contributes to the pathogenesis of mesangial-proliferative glomerulonephritis, thrombotic microangiopathy, and acute kidney injury. Conversely, certain C5b-9 signals limit complement-induced injury, or promote recovery of cells. In addition to C5b-9, complement cleavage products, such as C5a and C1q, can injure kidney cells. Thus, the complement system contributes to various kidney pathologies by causing cellular damage in both an inflammation-dependent and inflammation-independent manner.
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Affiliation(s)
- Tomoko Takano
- Department of Medicine, McGill University Health Centre, McGill University, Montreal, Quebec, Canada.
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Abstract
As recently as 2002, most cases of primary membranous nephropathy (MN), a relatively common cause of nephrotic syndrome in adults, were considered idiopathic. We now recognize that MN is an organ-specific autoimmune disease in which circulating autoantibodies bind to an intrinsic antigen on glomerular podocytes and form deposits of immune complexes in situ in the glomerular capillary walls. Here we define the clinical and pathological features of MN and describe the experimental models that enabled the discovery of the major target antigen, the M-type phospholipase A2 receptor 1 (PLA2R). We review the pathophysiology of experimental MN and compare and contrast it with the human disease. We discuss the diagnostic value of serological testing for anti-PLA2R and tissue staining for the redistributed antigen, and their utility for differentiating between primary and secondary MN, and between recurrent MN after kidney transplant and de novo MN. We end with consideration of how knowledge of the antigen might direct future therapeutic strategies.
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Beeken M, Lindenmeyer MT, Blattner SM, Radón V, Oh J, Meyer TN, Hildebrand D, Schlüter H, Reinicke AT, Knop JH, Vivekanandan-Giri A, Münster S, Sachs M, Wiech T, Pennathur S, Cohen CD, Kretzler M, Stahl RAK, Meyer-Schwesinger C. Alterations in the ubiquitin proteasome system in persistent but not reversible proteinuric diseases. J Am Soc Nephrol 2014; 25:2511-25. [PMID: 24722446 DOI: 10.1681/asn.2013050522] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Podocytes are the key cells affected in nephrotic glomerular kidney diseases, and they respond uniformly to injury with cytoskeletal rearrangement. In nephrotic diseases, such as membranous nephropathy and FSGS, persistent injury often leads to irreversible structural damage, whereas in minimal change disease, structural alterations are mostly transient. The factors leading to persistent podocyte injury are currently unknown. Proteolysis is an irreversible process and could trigger persistent podocyte injury through degradation of podocyte-specific proteins. We, therefore, analyzed the expression and functional consequence of the two most prominent proteolytic systems, the ubiquitin proteasome system (UPS) and the autophagosomal/lysosomal system, in persistent and transient podocyte injuries. We show that differential upregulation of both proteolytic systems occurs in persistent human and rodent podocyte injury. The expression of specific UPS proteins in podocytes differentiated children with minimal change disease from children with FSGS and correlated with poor clinical outcome. Degradation of the podocyte-specific protein α-actinin-4 by the UPS depended on oxidative modification in membranous nephropathy. Notably, the UPS was overwhelmed in podocytes during experimental glomerular disease, resulting in abnormal protein accumulation and compensatory upregulation of the autophagosomal/lysosomal system. Accordingly, inhibition of both proteolytic systems enhanced proteinuria in persistent nephrotic disease. This study identifies altered proteolysis as a feature of persistent podocyte injury. In the future, specific UPS proteins may serve as new biomarkers or therapeutic targets in persistent nephrotic syndrome.
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Affiliation(s)
| | - Maja T Lindenmeyer
- Institute of Physiology and Division of Nephrology, University of Zurich, Zurich, Switzerland
| | - Simone M Blattner
- Department of Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan; and
| | | | | | - Tobias N Meyer
- Department of Internal Medicine, Nephrology, University Affiliated Asklepios Clinic Hamburg Barmbek, Hamburg, Germany
| | - Diana Hildebrand
- Clinical Chemistry, Mass Spectrometry and Proteome Analysis, and
| | - Hartmut Schlüter
- Clinical Chemistry, Mass Spectrometry and Proteome Analysis, and
| | | | | | - Anuradha Vivekanandan-Giri
- Department of Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan; and
| | | | | | - Thorsten Wiech
- Pathology, Division of Renal Pathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Subramaniam Pennathur
- Department of Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan; and
| | - Clemens D Cohen
- Institute of Physiology and Division of Nephrology, University of Zurich, Zurich, Switzerland
| | - Matthias Kretzler
- Department of Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan; and
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Immunopathogenesis of membranous nephropathy: an update. Semin Immunopathol 2014; 36:381-97. [PMID: 24715030 DOI: 10.1007/s00281-014-0423-y] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 03/17/2014] [Indexed: 10/25/2022]
Abstract
Membranous nephropathy (MN) is a non-inflammatory organ-specific autoimmune disease which affects the kidney glomerulus, resulting in the formation of immune deposits on the outer aspect of the glomerular basement membrane, complement-mediated proteinuria, and severe renal failure in 30% of patients. In the last 10 years, substantial advances have been made in the understanding of the molecular bases of MN, with the identification of several antigens and predisposing genes in children and adults. These ground-breaking findings already have a major impact on diagnosis and monitoring and to some extent on therapies. However, there is evidence that the disease is more complex and involves a variety of antigen-antibody systems and genes involved in immune response, progression, recovery, and protective mechanisms. We herein review these recent findings which open new perspectives of research. Understanding the complex pathogenesis of MN will offer many opportunities for future therapeutic interventions and will hopefully have a major impact on patient care. New insights into the molecular mechanisms of MN may also enlighten the pathogenesis of organ-specific autoimmune diseases.
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Sun Y, Zhang H, Hu R, Sun J, Mao X, Zhao Z, Chen Q, Zhang Z. The expression and significance of neuronal iconic proteins in podocytes. PLoS One 2014; 9:e93999. [PMID: 24699703 PMCID: PMC3974844 DOI: 10.1371/journal.pone.0093999] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 03/10/2014] [Indexed: 11/18/2022] Open
Abstract
Growing evidence suggests that there are many common cell biological features shared by neurons and podocytes; however, the mechanism of podocyte foot process formation remains unclear. Comparing the mechanisms of process formation between two cell types should provide useful guidance from the progress of neuron research. Studies have shown that some mature proteins of podocytes, such as podocin, nephrin, and synaptopodin, were also expressed in neurons. In this study, using cell biological experiments and immunohistochemical techniques, we showed that some neuronal iconic molecules, such as Neuron-specific enolase, nestin and Neuron-specific nuclear protein, were also expressed in podocytes. We further inhibited the expression of Neuron-specific enolase, nestin, synaptopodin and Ubiquitin carboxy terminal hydrolase-1 by Small interfering RNA in cultured mouse podocytes and observed the significant morphological changes in treated podocytes. When podocytes were treated with Adriamycin, the protein expression of Neuron-specific enolase, nestin, synaptopodin and Ubiquitin carboxy terminal hydrolase-1 decreased over time. Meanwhile, the morphological changes in the podocytes were consistent with results of the Small interfering RNA treatment of these proteins. The data demonstrated that neuronal iconic proteins play important roles in maintaining and regulating the formation and function of podocyte processes.
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Affiliation(s)
- Yu Sun
- Department of Pathology, Key Laboratory of Molecular Medicine, Chinese Ministry of Education, Shanghai Medical College, School of Basic Medical Science, Fudan University, Shanghai, P.R. China
| | - Hongxia Zhang
- Department of Pathology, Weifang Medical University, Weifang, Shandong, P.R. China
| | - Ruimin Hu
- Department of Pathology, Key Laboratory of Molecular Medicine, Chinese Ministry of Education, Shanghai Medical College, School of Basic Medical Science, Fudan University, Shanghai, P.R. China
| | - Jianyong Sun
- Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, P.R. China
| | - Xing Mao
- Department of Pathology, Key Laboratory of Molecular Medicine, Chinese Ministry of Education, Shanghai Medical College, School of Basic Medical Science, Fudan University, Shanghai, P.R. China
| | - Zhonghua Zhao
- Department of Pathology, Key Laboratory of Molecular Medicine, Chinese Ministry of Education, Shanghai Medical College, School of Basic Medical Science, Fudan University, Shanghai, P.R. China
| | - Qi Chen
- Department of Pathology, Key Laboratory of Molecular Medicine, Chinese Ministry of Education, Shanghai Medical College, School of Basic Medical Science, Fudan University, Shanghai, P.R. China
| | - Zhigang Zhang
- Department of Pathology, Key Laboratory of Molecular Medicine, Chinese Ministry of Education, Shanghai Medical College, School of Basic Medical Science, Fudan University, Shanghai, P.R. China
- * E-mail:
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Read NC, Gutsol A, Holterman CE, Carter A, Coulombe J, Gray DA, Kennedy CRJ. Ubiquitin C-terminal hydrolase L1 deletion ameliorates glomerular injury in mice with ACTN4-associated focal segmental glomerulosclerosis. Biochim Biophys Acta Mol Basis Dis 2014; 1842:1028-40. [PMID: 24662305 DOI: 10.1016/j.bbadis.2014.03.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 03/13/2014] [Accepted: 03/15/2014] [Indexed: 11/19/2022]
Abstract
Renal ubiquitin C-terminal hydrolase L1 (UCHL1) is upregulated in a subset of human glomerulopathies, including focal segmental glomerulosclerosis (FSGS), where it may serve to promote ubiquitin pools for degradation of cytotoxic proteins. In the present study, we tested whether UCHL1 is expressed in podocytes of a mouse model of ACTN4-associated FSGS. Podocyte UCHL1 protein was detected in glomeruli of K256E-ACTN4(pod+)/UCHL1+/+ mice. UCHL1+/- mice were intercrossed with K256E-ACTN4(pod+) mice and monitored for features of glomerular disease. 10-week-old K256E-ACTN4(pod+)/UCHL1-/- mice exhibited significantly ameliorated albuminuria, glomerulosclerosis, tubular pathology and blood pressure. Interestingly, while UCHL1 deletion diminished both tubular and glomerular apoptosis, WT1-positive nuclei were unchanged. Finally, UCHL1 levels correlated positively with poly-ubiquitinated proteins but negatively with K256E-α-actinin-4 levels, implying reduced K256E-α-actinin-4 proteolysis in the absence of UCHL1. Our data suggest that UCHL1 upregulation in ACTN4-associated FSGS fuels the proteasome and that UCHL1 deletion may impair proteolysis and thereby preserve K256E/wt-α-actinin-4 heterodimers, maintaining podocyte cytoskeletal integrity and protecting the glomerular filtration barrier.
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Affiliation(s)
- Naomi C Read
- Kidney Research Centre, The Ottawa Hospital, Ottawa, Ontario, Canada; Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada; Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Alex Gutsol
- Kidney Research Centre, The Ottawa Hospital, Ottawa, Ontario, Canada; Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada
| | - Chet E Holterman
- Kidney Research Centre, The Ottawa Hospital, Ottawa, Ontario, Canada; Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada
| | - Anthony Carter
- Kidney Research Centre, The Ottawa Hospital, Ottawa, Ontario, Canada; Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada
| | - Josée Coulombe
- Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada
| | - Douglas A Gray
- Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada; Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Chris R J Kennedy
- Kidney Research Centre, The Ottawa Hospital, Ottawa, Ontario, Canada; Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada; Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
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35
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Lohmann F, Sachs M, Meyer TN, Sievert H, Lindenmeyer MT, Wiech T, Cohen CD, Balabanov S, Stahl RAK, Meyer-Schwesinger C. UCH-L1 induces podocyte hypertrophy in membranous nephropathy by protein accumulation. Biochim Biophys Acta Mol Basis Dis 2014; 1842:945-58. [PMID: 24583340 DOI: 10.1016/j.bbadis.2014.02.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Revised: 02/18/2014] [Accepted: 02/21/2014] [Indexed: 11/18/2022]
Abstract
Podocytes are terminally differentiated cells of the glomerular filtration barrier that react with hypertrophy in the course of injury such as in membranous nephropathy (MGN). The neuronal deubiquitinase ubiquitin C-terminal hydrolase L1 (UCH-L1) is expressed and activated in podocytes of human and rodent MGN. UCH-L1 regulates the mono-ubiquitin pool and induces accumulation of poly-ubiquitinated proteins in affected podocytes. Here, we investigated the role of UCH-L1 in podocyte hypertrophy and in the homeostasis of the hypertrophy associated "model protein" p27(Kip1). A better understanding of the basic mechanisms leading to podocyte hypertrophy is crucial for the development of specific therapies in MGN. In human and rat MGN, hypertrophic podocytes exhibited a simultaneous up-regulation of UCH-L1 and of cytoplasmic p27(Kip1) content. Functionally, inhibition of UCH-L1 activity and knockdown or inhibition of UCH-L1 attenuated podocyte hypertrophy by decreasing the total protein content in isolated glomeruli and in cultured podocytes. In contrast, UCH-L1 levels and activity increased podocyte hypertrophy and total protein content in culture, specifically of cytoplasmic p27(Kip1). UCH-L1 enhanced cytoplasmic p27(Kip1) levels by nuclear export and decreased poly-ubiquitination and proteasomal degradation of p27(Kip1). In parallel, UCH-L1 increased podocyte turnover, migration and cytoskeletal rearrangement, which are associated with known oncogenic functions of cytoplasmic p27(Kip1) in cancer. We propose that UCH-L1 induces podocyte hypertrophy in MGN by increasing the total protein content through altered degradation and accumulation of proteins such as p27(Kip1) in the cytoplasm of podocytes. Modification of both UCH-L1 activity and levels could be a new therapeutic avenue to podocyte hypertrophy in MGN.
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Affiliation(s)
- Frithjof Lohmann
- Department of Internal Medicine, Nephrology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Marlies Sachs
- Department of Internal Medicine, Nephrology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tobias N Meyer
- Department of Internal Medicine, Nephrology, Asklepios Klinikum Barmbek, Hamburg, Germany
| | - Henning Sievert
- Department of Oncology, Haematology and Bone Marrow Transplantation with Section Pneumology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Maja T Lindenmeyer
- Institute of Physiology and Division of Nephrology, University of Zurich, Switzerland
| | - Thorsten Wiech
- Department of Pathology, Division of Renal Pathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Clemens D Cohen
- Institute of Physiology and Division of Nephrology, University of Zurich, Switzerland
| | | | - R A K Stahl
- Department of Internal Medicine, Nephrology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Sosna J, Voigt S, Mathieu S, Kabelitz D, Trad A, Janssen O, Meyer-Schwesinger C, Schütze S, Adam D. The proteases HtrA2/Omi and UCH-L1 regulate TNF-induced necroptosis. Cell Commun Signal 2013; 11:76. [PMID: 24090154 PMCID: PMC3850939 DOI: 10.1186/1478-811x-11-76] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 10/01/2013] [Indexed: 11/23/2022] Open
Abstract
Background In apoptosis, proteolysis by caspases is the primary mechanism for both initiation and execution of programmed cell death (PCD). In contrast, the impact of proteolysis on the regulation and execution of caspase-independent forms of PCD (programmed necrosis, necroptosis) is only marginally understood. Likewise, the identity of the involved proteases has remained largely obscure. Here, we have investigated the impact of proteases in TNF-induced necroptosis. Results The serine protease inhibitor TPKC protected from TNF-induced necroptosis in multiple murine and human cells systems whereas inhibitors of metalloproteinases or calpain/cysteine and cathepsin proteases had no effect. A screen for proteins labeled by a fluorescent TPCK derivative in necroptotic cells identified HtrA2/Omi (a serine protease previously implicated in PCD) as a promising candidate. Demonstrating its functional impact, pharmacological inhibition or genetic deletion of HtrA2/Omi protected from TNF-induced necroptosis. Unlike in apoptosis, HtrA2/Omi did not cleave another protease, ubiquitin C-terminal hydrolase (UCH-L1) during TNF-induced necroptosis, but rather induced monoubiquitination indicative for UCH-L1 activation. Correspondingly, pharmacologic or RNA interference-mediated inhibition of UCH-L1 protected from TNF-induced necroptosis. We found that UCH-L1 is a mediator of caspase-independent, non-apoptotic cell death also in diseased kidney podocytes by measuring cleavage of the protein PARP-1, caspase activity, cell death and cell morphology. Indicating a role of TNF in this process, podocytes with stably downregulated UCH-L1 proved resistant to TNF-induced necroptosis. Conclusions The proteases HtrA2/Omi and UCH-L1 represent two key components of TNF-induced necroptosis, validating the relevance of proteolysis not only for apoptosis, but also for caspase-independent PCD. Since UCH-L1 clearly contributes to the non-apoptotic death of podocytes, interference with the necroptotic properties of HtrA2/Omi and UCH-L1 may prove beneficial for the treatment of patients, e.g. in kidney failure.
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Affiliation(s)
- Justyna Sosna
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr, 5, 24105 Kiel, Germany.
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Cybulsky AV. The intersecting roles of endoplasmic reticulum stress, ubiquitin–proteasome system, and autophagy in the pathogenesis of proteinuric kidney disease. Kidney Int 2013; 84:25-33. [DOI: 10.1038/ki.2012.390] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 08/27/2012] [Accepted: 09/07/2012] [Indexed: 12/12/2022]
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The expression of podocyte-specific proteins in parietal epithelial cells is regulated by protein degradation. Kidney Int 2013; 84:532-44. [PMID: 23615505 DOI: 10.1038/ki.2013.115] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 01/23/2013] [Accepted: 01/24/2013] [Indexed: 11/08/2022]
Abstract
The role of parietal epithelial cells (PECs) in glomerular disease is unclear because they also express podocyte proteins under pathophysiological conditions. To help resolve this, we established a novel PEC isolation technique in rats and mice to investigate which regulatory mechanisms lead to podocyte protein expression in PECs. This pure pool of naive PECs was then compared with PECs in primary culture and immortalized PECs in permanent culture. The naive PECs expressed low levels of podocyte-specific mRNA. Accordingly, in crescentic glomerulonephritis, single PECs activated the podocin promoter in vivo. In primary culture, PECs expressed a distinct morphology from podocytes but with high transcript and protein levels of PEC markers. In contrast to naive PECs, cultured PECs also expressed podocyte proteins, and this correlated with reduced proteolytic activity but not with increased transcript levels. Activation of autophagy or proteasomal degradation decreased the levels of podocyte proteins in PECs, whereas inhibition of proteasomal degradation led to the stabilization of podocyte proteins in PECs. Thus, naive PECs express podocyte transcripts physiologically and these podocyte proteins are stable under pathological conditions through decreased proteolysis.
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Zhang H, Sun Y, Hu R, Luo W, Mao X, Zhao Z, Chen Q, Zhang Z. The regulation of the UCH-L1 gene by transcription factor NF-κB in podocytes. Cell Signal 2013; 25:1574-85. [PMID: 23567262 DOI: 10.1016/j.cellsig.2013.03.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 03/23/2013] [Accepted: 03/28/2013] [Indexed: 11/19/2022]
Abstract
In kidney, the ubiquitin carboxy-terminal hydrolase 1 (UCH-L1) is involved in podocyte injury and proteinuria but details of the mechanism underlying its regulation are not known. Activation of NF-κB is thought to be the predominant risk factor for kidney disease; therefore, it is postulated that UCH-L1 may be one of the NF-κB target genes. In this study, we investigated the involvement of NF-κB activation in the regulation of UCH-L1 expression and the function of murine podocytes. Stimulation of podocytes with the cytokines TNF-α and IL-1β up-regulated UCH-L1 expression rapidly at the mRNA and protein levels and the NF-κB-specific inhibitor pyrrolidine dithiocarbamate resulted in down-regulation. NF-κB up-regulates UCH-L1 via binding the --300 bp and --109 bp sites of its promoter, which was confirmed by the electrophoretic mobility shift assay of DNA-nuclear protein binding. In the renal biopsy from lupus nephritis patients, the expressions of NF-κB and UCH-L1 increased in immunohistochestry staining and were positively correlated. Activation of NF-κB up-regulates UCH-L1 expression following changing of other podocytes molecules, such as nephrin and snail. These results suggest that activation of the NF-κB signaling pathway could be the major pathogenesis to up-regulate UCH-L1 in podocyte injury, followed by the turnover of other molecules, which might result in morphological changes and dysfunction of podocytes. This work help us to understand the effect of NF-κB on specific target molecules of podocytes, and suggest that targeting the NF-κB-UCH-L1 interaction could be a novel therapeutic strategy for the treatment of podocyte lesions and proteinuria.
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Affiliation(s)
- Hongxia Zhang
- Department of Pathology and Key Laboratory of Molecular Medicine, School of Basic Medical Sciences, Fudan University, Shanghai, People's Republic of China.
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Gopalakrishnan K, Kumarasamy S, Yan Y, Liu J, Kalinoski A, Kothandapani A, Farms P, Joe B. Increased Expression of Rififylin in A < 330 Kb Congenic Strain is Linked to Impaired Endosomal Recycling in Proximal Tubules. Front Genet 2012; 3:138. [PMID: 22891072 PMCID: PMC3413941 DOI: 10.3389/fgene.2012.00138] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2012] [Accepted: 07/11/2012] [Indexed: 11/13/2022] Open
Abstract
Cell surface proteins are internalized into the cell through endocytosis and either degraded within lysosomes or recycled back to the plasma membrane. While perturbations in endosomal internalization are known to modulate renal function, it is not known whether similar alterations in recycling affect renal function. Rififylin is a known regulator of endocytic recycling with E3 ubiquitin protein ligase activity. In this study, using two genetically similar strains, the Dahl Salt-sensitive rat and an S.LEW congenic strain, which had allelic variants within a < 330 kb segment containing rififylin, we tested the hypothesis that alterations in endosomal recycling affect renal function. The congenic strain had 1.59-fold higher renal expression of rififylin. Transcriptome analysis indicated that components of both endocytosis and recycling were upregulated in the congenic strain. Transcription of Atp1a1 and cell surface content of the protein product of Atp1a1, the alpha subunit of Na+K+ATPase were increased in the proximal tubules from the congenic strain. Because rififylin does not directly regulate endocytosis and it is also a differentially expressed gene within the congenic segment, we reasoned that the observed alterations in the transcriptome of the congenic strain constitute a feedback response to the primary functional alteration of recycling caused by rififylin. To test this, recycling of transferrin was studied in isolated proximal tubules. Recycling was significantly delayed within isolated proximal tubules of the congenic strain, which also had a higher level of polyubiquitinated proteins and proteinuria compared with S. These data provide evidence to suggest that delayed endosomal recycling caused by excess of rififylin indirectly affects endocytosis, enhances intracellular protein polyubiquitination and contributes to proteinuria.
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Affiliation(s)
- Kathirvel Gopalakrishnan
- Center for Hypertension and Personalized Medicine, University of Toledo College of Medicine and Life Sciences Toledo, OH, USA
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Kitzler TM, Papillon J, Guillemette J, Wing SS, Cybulsky AV. Complement modulates the function of the ubiquitin–proteasome system and endoplasmic reticulum-associated degradation in glomerular epithelial cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:1007-16. [DOI: 10.1016/j.bbamcr.2012.03.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 03/01/2012] [Accepted: 03/01/2012] [Indexed: 11/29/2022]
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