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Guo L, Yan H, Gong Q, Zheng W, Zhong L, Gong T, Sun X, Zhang Z, Ping Y, Zhu Z, Xu J, Zhang Y. Glomerulus-Targeted ROS-Responsive Polymeric Nanoparticles for Effective Membranous Nephropathy Therapy. ACS APPLIED MATERIALS & INTERFACES 2024; 16:35447-35462. [PMID: 38940537 DOI: 10.1021/acsami.4c04345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/29/2024]
Abstract
Membranous nephropathy (MN) is a common immune-mediated glomerular disease that requires the development of safe and highly effective therapies. Celastrol (CLT) has shown promise as a therapeutic molecule candidate, but its clinical use is currently limited due to off-target toxicity. Given that excess levels of reactive oxygen species (ROS) contributing to podocyte damage is a key driver of MN progression to end-stage renal disease, we rationally designed ROS-responsive cationic polymeric nanoparticles (PPS-CPNs) with a well-defined particle size and surface charge by employing poly(propylene sulfide)-polyethylene glycol (PPS-PEG) and poly(propylene sulfide)-polyethylenimine (PPS-PEI) to selectively deliver CLT to the damaged glomerulus for MN therapy. Experimental results show that PPS-CPNs successfully crossed the fenestrated endothelium, accumulated in the glomerular basement membrane (GBM), and were internalized by podocytes where rapid drug release was triggered by the overproduction of ROS, thereby outperforming nonresponsive CLT nanotherapy to alleviate subepithelial immune deposits, podocyte foot process effacement, and GBM expansion in a rat MN model. Moreover, the ROS-responsive CLT nanotherapy was associated with significantly lower toxicity to major organs than free CLT. These results suggest that encapsulating CLT into PPS-CPNs can improve efficacy and reduce toxicity as a promising treatment option for MN.
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Affiliation(s)
- Ling Guo
- National Engineering Technology Research Center for Miao Medicine, Guizhou Engineering Technology Research Center for Processing and Preparation of Traditional Chinese Medicine and Ethnic Medicine, College of Pharmaceutical Sciences, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, P. R. China
| | - Hanyu Yan
- National Engineering Technology Research Center for Miao Medicine, Guizhou Engineering Technology Research Center for Processing and Preparation of Traditional Chinese Medicine and Ethnic Medicine, College of Pharmaceutical Sciences, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, P. R. China
| | - Qinqin Gong
- National Engineering Technology Research Center for Miao Medicine, Guizhou Engineering Technology Research Center for Processing and Preparation of Traditional Chinese Medicine and Ethnic Medicine, College of Pharmaceutical Sciences, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, P. R. China
| | - Weili Zheng
- National Engineering Technology Research Center for Miao Medicine, Guizhou Engineering Technology Research Center for Processing and Preparation of Traditional Chinese Medicine and Ethnic Medicine, College of Pharmaceutical Sciences, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, P. R. China
| | - Liang Zhong
- National Engineering Technology Research Center for Miao Medicine, Guizhou Engineering Technology Research Center for Processing and Preparation of Traditional Chinese Medicine and Ethnic Medicine, College of Pharmaceutical Sciences, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, P. R. China
| | - Tao Gong
- West China School of Pharmacy, Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, Sichuan University, Chengdu 610041, P. R. China
| | - Xun Sun
- West China School of Pharmacy, Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, Sichuan University, Chengdu 610041, P. R. China
| | - Zhirong Zhang
- West China School of Pharmacy, Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, Sichuan University, Chengdu 610041, P. R. China
| | - Yuan Ping
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, P. R. China
| | - Zilan Zhu
- UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, U.K
| | - Jian Xu
- National Engineering Technology Research Center for Miao Medicine, Guizhou Engineering Technology Research Center for Processing and Preparation of Traditional Chinese Medicine and Ethnic Medicine, College of Pharmaceutical Sciences, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, P. R. China
| | - Yongping Zhang
- National Engineering Technology Research Center for Miao Medicine, Guizhou Engineering Technology Research Center for Processing and Preparation of Traditional Chinese Medicine and Ethnic Medicine, College of Pharmaceutical Sciences, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, P. R. China
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Zhao YL, Zhang XH, Guo F, Wei Y, Shang JH, Luo XD. Yi Shen An, a Chinese traditional prescription, ameliorates membranous glomerulonephritis induced by cationic bovine serum albumin in rats. PHARMACEUTICAL BIOLOGY 2022; 60:163-174. [PMID: 35001799 PMCID: PMC8745358 DOI: 10.1080/13880209.2021.2021947] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 11/15/2021] [Accepted: 12/19/2021] [Indexed: 06/14/2023]
Abstract
CONTEXT Yi Shen An (YSA) is an investigational composite of traditional Chinese medicine (Reference: 2010L000974) for the treatment of renal disease. OBJECTIVE To investigate the protective effects of YSA against membranous glomerulonephritis (MGN). MATERIALS AND METHODS Male Sprague-Dawley rats were injected with cationic bovine serum albumin (C-BSA) to create a model of MGN. Then, rats were orally treated with YSA at doses of 0.25, 0.5, 1 and 2 g/kg for 35 successive days; prednisone (5 mg/kg) was used as a positive control. At the end of the experimental period, we performed a series of tests, including 24 h urinary protein, and biochemical, immunological, antioxidative, coagulation indices, and histopathological examination. RESULTS YSA-1 g/kg significantly lowered urinary protein from 68.37 to 30.74 mg (p < 0.01). Meantime, total protein (TP) and albumin (ALB) recovered from 66.26 and 20.51 g/L to 76.08 and 35.64 g/L (p < 0.01), respectively. YSA removed the deposition of immunoglobulin G (IgG) and complement 3c (C3c), prevented inter-capillary cell hyperplasia on the glomerular basement membrane (GBM), and reduced electron-dense deposits and fusion of podocytes. In addition, serum IgG and superoxide dismutase were significantly elevated. In contrast, malondialdehyde, total cholesterol, triglyceride, circulating immune complex (CIC), and immunoglobulin M decreased in the YSA-treated group. Moreover, the blood coagulation dysfunction was adjusted. DISCUSSION AND CONCLUSIONS These findings indicate YSA may exert a therapeutic effect against MGN through the inhibition of CIC formation, and the removal of IgG and C3c deposition from the GBM, thus supporting the development of further clinical trials.
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Affiliation(s)
- Yun-Li Zhao
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Provincial Center for Research & Development of Natural Products, School of Chemical Science and Technology, Yunnan University, Kunming, P. R. China
| | - Xiang-Hua Zhang
- New Drug R&D Department of Kunming Institute of Kidney Disease, Kunming, P. R. China
| | - Feng Guo
- New Drug R&D Department of Kunming Institute of Kidney Disease, Kunming, P. R. China
| | - Ying Wei
- Shang Hai University of Medicine & Health Sciences, Shang Hai, P. R. China
| | - Jian-Hua Shang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, P. R. China
| | - Xiao-Dong Luo
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Provincial Center for Research & Development of Natural Products, School of Chemical Science and Technology, Yunnan University, Kunming, P. R. China
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, P. R. China
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Membranous nephropathy: new pathogenic mechanisms and their clinical implications. Nat Rev Nephrol 2022; 18:466-478. [PMID: 35484394 DOI: 10.1038/s41581-022-00564-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2022] [Indexed: 12/24/2022]
Abstract
Membranous nephropathy (MN) is characterized histomorphologically by the presence of immune deposits in the subepithelial space of the glomerular filtration barrier; its clinical hallmarks are nephrotic range proteinuria with oedema. In patients with primary MN, autoimmunity is driven by circulating autoantibodies that bind to one or more antigens on the surface of glomerular podocytes. Compared with other autoimmune kidney diseases, the understanding of the pathogenesis of MN has substantially improved in the past decade, thanks to the discovery of pathogenic circulating autoantibodies against phospholipase A2 receptor 1 (PLA2R1) and thrombospondin type 1 domain-containing protein 7A (THSD7A). The subsequent identification of more proteins associated with MN, some of which are also endogenous podocyte antigens, might further advance the clinical characterization of MN, including its diagnosis, treatment and prognosis. Insights from studies in patients with MN, combined with the development of novel in vivo and in vitro experimental models, have potential to improve the management of patients with MN. Characterizing the interaction between autoimmunity and local glomerular lesions provides an opportunity to develop more specific, pathogenesis-based treatments.
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Möller-Hackbarth K, Dabaghie D, Charrin E, Zambrano S, Genové G, Li X, Wernerson A, Lal M, Patrakka J. Retinoic acid receptor responder1 promotes development of glomerular diseases via the Nuclear Factor-κB signaling pathway. Kidney Int 2021; 100:809-823. [PMID: 34147551 DOI: 10.1016/j.kint.2021.05.036] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 05/11/2021] [Accepted: 05/20/2021] [Indexed: 12/20/2022]
Abstract
Inflammatory pathways are activated in most glomerular diseases but molecular mechanisms driving them in kidney tissue are poorly known. We identified retinoic acid receptor responder 1 (Rarres1) as a highly podocyte-enriched protein in healthy kidneys. Studies in podocyte-specific knockout animals indicated that Rarres1 was not needed for the normal development or maintenance of the glomerulus filtration barrier and did not modulate the outcome of kidney disease in a model of glomerulonephritis. Interestingly, we detected an induction of Rarres1 expression in glomerular and peritubular capillary endothelial cells in IgA and diabetic kidney disease, as well as in ANCA-associated vasculitis. Analysis of publicly available RNA data sets showed that the induction of Rarres1 expression was a common molecular mechanism in chronic kidney diseases. A conditional knock-in mouse line, overexpressing Rarres1 specifically in endothelial cells, did not show any obvious kidney phenotype. However, the overexpression promoted the progression of kidney damage in a model of glomerulonephritis. In line with this, conditional knock-out mice, lacking Rarres1 in endothelial cells, were partially protected in the disease model. Mechanistically, Rarres1 promoted inflammation and fibrosis via transcription factor Nuclear Factor-κB signaling pathway by activating receptor tyrosine kinase Axl. Thus, induction of Rarres1 expression in endothelial cells is a prevalent molecular mechanism in human glomerulopathies and this seems to have a pathogenic role in driving inflammation and fibrosis via the Nuclear Factor-κB signaling pathway.
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Affiliation(s)
- Katja Möller-Hackbarth
- KI/AZ Integrated Cardio Metabolic Centre, Karolinska Institutet at Karolinska University Hospital, Huddinge, Stockholm, Sweden; Department of Laboratory Medicine, Division of Pathology, Karolinska Institutet at Karolinska University Hospital, Huddinge, Stockholm, Sweden
| | - Dina Dabaghie
- KI/AZ Integrated Cardio Metabolic Centre, Karolinska Institutet at Karolinska University Hospital, Huddinge, Stockholm, Sweden; Department of Laboratory Medicine, Division of Pathology, Karolinska Institutet at Karolinska University Hospital, Huddinge, Stockholm, Sweden
| | - Emmanuelle Charrin
- KI/AZ Integrated Cardio Metabolic Centre, Karolinska Institutet at Karolinska University Hospital, Huddinge, Stockholm, Sweden; Department of Laboratory Medicine, Division of Pathology, Karolinska Institutet at Karolinska University Hospital, Huddinge, Stockholm, Sweden
| | - Sonia Zambrano
- KI/AZ Integrated Cardio Metabolic Centre, Karolinska Institutet at Karolinska University Hospital, Huddinge, Stockholm, Sweden; Department of Laboratory Medicine, Division of Pathology, Karolinska Institutet at Karolinska University Hospital, Huddinge, Stockholm, Sweden
| | - Guillem Genové
- KI/AZ Integrated Cardio Metabolic Centre, Karolinska Institutet at Karolinska University Hospital, Huddinge, Stockholm, Sweden; Department of Medicine Huddinge, Division of Pathology, Karolinska Institutet at Karolinska University Hospital, Huddinge, Stockholm, Sweden
| | - Xidan Li
- KI/AZ Integrated Cardio Metabolic Centre, Karolinska Institutet at Karolinska University Hospital, Huddinge, Stockholm, Sweden; Department of Medicine Huddinge, Division of Pathology, Karolinska Institutet at Karolinska University Hospital, Huddinge, Stockholm, Sweden
| | - Annika Wernerson
- Department of Clinical Sciences, Division of Renal Medicine, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Mark Lal
- Bioscience Renal, Research and Early Development Cardiovascular, Renal and Metabolism (CVRM), R&D Biopharmaceuticals, AstraZeneca, Gothenburg, Sweden
| | - Jaakko Patrakka
- KI/AZ Integrated Cardio Metabolic Centre, Karolinska Institutet at Karolinska University Hospital, Huddinge, Stockholm, Sweden; Department of Laboratory Medicine, Division of Pathology, Karolinska Institutet at Karolinska University Hospital, Huddinge, Stockholm, Sweden.
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Reinhard L, Stahl RAK, Hoxha E. Is primary membranous nephropathy a complement mediated disease? Mol Immunol 2020; 128:195-204. [PMID: 33142137 DOI: 10.1016/j.molimm.2020.10.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/04/2020] [Accepted: 10/20/2020] [Indexed: 12/25/2022]
Abstract
Membranous nephropathy (MN) is an immune complex mediated disease. Although limited to the kidney, in up to 20% of patients MN is associated with other autoimmune, infectious or malignant diseases. The initial pathogenetic event in what is still considered "primary" MN is the binding of circulating autoantibodies to proteins (autoantigens) expressed in glomerular podocytes. This antibody binding leads to the formation of immune complexes in the glomerular basement membrane. There is clinical and experimental evidence that these immune deposits lead to the activation of the complement system. Experimental studies in the MN model of Heymann's nephritis show that the terminal membrane attack complex (MAC) of the complement system induces a disturbance of the glomerular filtration barrier and leads to proteinuria, the clinical hallmark of MN. After the discovery of the phospholipase A2 receptor 1 and thrombospondin type 1 domain containing protein 7A as endogenous antigens, it is assumed that IgG4 antibodies directed against these proteins induce MN in over 85% of patients with primary MN. As a result, the role of complement in the pathogenesis of MN needs to be defined in light of these developments. In this review we describe the current knowledge on the function of the complement system in primary MN and discuss the open questions, which have to be solved for a better understanding of the potential role of complement in the pathophysiology of primary MN.
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Affiliation(s)
- Linda Reinhard
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Rolf A K Stahl
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
| | - Elion Hoxha
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
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Lateb M, Ouahmi H, Payré C, Brglez V, Zorzi K, Dolla G, Zaidan M, Boyer-Suavet S, Knebelmann B, Crépin T, Courivaud C, Jourde-Chiche N, Esnault V, Lambeau G, Seitz-Polski B. Anti-PLA2R1 Antibodies Containing Sera Induce In Vitro Cytotoxicity Mediated by Complement Activation. J Immunol Res 2019; 2019:1324804. [PMID: 32083137 PMCID: PMC7012209 DOI: 10.1155/2019/1324804] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 11/08/2019] [Accepted: 11/13/2019] [Indexed: 12/13/2022] Open
Abstract
The phospholipase A2 receptor (PLA2R1) is the major autoantigen in idiopathic membranous nephropathy (MN). However, the pathogenic role of anti-PLA2R1 autoantibodies is unclear. Our aim was to evaluate the in vitro cytotoxicity of anti-PLA2R1 antibodies mediated by complement. Forty-eight patients with PLA2R1-related MN from the prospective cohort SOURIS were included. Anti-PLA2R1 titer, epitope profile, and anti-PLA2R1 IgG subclasses were characterized by ELISA. Cell cytotoxicity was evaluated by immunofluorescence in HEK293 cells overexpressing PLA2R1 incubated with patient or healthy donor sera in the presence or absence of rabbit complement or complement inhibitors. Mean cytotoxicity of anti-PLA2R1 sera for HEK293 cells overexpressing PLA2R1 was 2 ± 2%, which increased to 24 ± 6% after addition of rabbit complement (p < 0.001) (n = 48). GVB-EDTA, which inhibits all complement activation pathways, completely blocked cell cytotoxicity, whereas Mg-EGTA, which only inhibits the classical and lectin pathways, highly decreased suggesting a limited role of the alternative pathway. A higher diversity of IgG subclasses beyond IgG4 and high titer of total IgG anti-PLA2R1 were associated with increased cytotoxicity (p = 0.01 and p = 0.03 respectively). In a cohort of 37 patients treated with rituximab, high level of complement-mediated cytotoxicity was associated with less and delayed remission at month 6 after rituximab therapy (5/12 vs. 20/25 (p = 0.03) in 8.5 months ± 4.4 vs. 4.8 ± 4.0 (p = 0.02)). Kaplan-Meier analysis demonstrated that high level of cytotoxicity (≥40%) (p = 0.005), epitope spreading (defined by immunization beyond the immunodominant CysR domain) (p = 0.002), and high titer of anti-PLA2R1 total IgG (p = 0.01) were factors of poor renal prognosis. Anti-PLA2R1 antibodies containing sera can induce in vitro cytotoxicity mediated by complement activation, and the level of cytotoxicity increases with the diversity and the titer of anti-PLA2R1 IgG subclasses. These patients with high level of complement-mediated cytotoxicity could benefit from adjuvant therapy using complement inhibitor associated with rituximab to induce earlier remission and less podocyte injury.
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Affiliation(s)
- Maël Lateb
- Université Côte d'Azur, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275, Valbonne Sophia Antipolis, France
| | - Hajar Ouahmi
- Service de Néphrologie-Dialyse-Transplantation, Hôpital Pasteur, CHU de Nice, Université de Nice-Sophia Antipolis, France
| | - Christine Payré
- Université Côte d'Azur, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275, Valbonne Sophia Antipolis, France
| | - Vesna Brglez
- Centre de Référence Maladies Rares Syndrome Néphrotique Idiopathique, CHU de Nice, Université de Nice-Sophia Antipolis, France
| | - Kevin Zorzi
- Centre de Référence Maladies Rares Syndrome Néphrotique Idiopathique, CHU de Nice, Université de Nice-Sophia Antipolis, France
| | - Guillaume Dolla
- Université Côte d'Azur, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275, Valbonne Sophia Antipolis, France
| | - Mohamad Zaidan
- Service de Néphrologie-Transplantation, Hôpital de Bicêtre, AP-HM France, Université Paris-Saclay, Villejuif, Paris, France
| | - Sonia Boyer-Suavet
- Centre de Référence Maladies Rares Syndrome Néphrotique Idiopathique, CHU de Nice, Université de Nice-Sophia Antipolis, France
| | - Bertrand Knebelmann
- Université Paris Descartes, Sorbonne Paris Cité, Hôpital Necker-Enfants Malades, Paris, France
- INSERM U1151, Institut Necker Enfants Malades, Hôpital Necker-Enfants Malades, Paris, France
| | - Thomas Crépin
- Département de Néphrologie, Dialyse et Transplantation, Université de Franche-Comté, Besançon, France
| | - Cécile Courivaud
- Département de Néphrologie, Dialyse et Transplantation, Université de Franche-Comté, Besançon, France
| | - Noémie Jourde-Chiche
- Aix-Marseille Univ, C2VN, INSERM 1263, INRA 1260, AP-HM Hôpital de la Conception, Centre de Néphrologie et Transplantation Rénale, Marseille, France
| | - Vincent Esnault
- Service de Néphrologie-Dialyse-Transplantation, Hôpital Pasteur, CHU de Nice, Université de Nice-Sophia Antipolis, France
- Centre de Référence Maladies Rares Syndrome Néphrotique Idiopathique, CHU de Nice, Université de Nice-Sophia Antipolis, France
| | - Gérard Lambeau
- Université Côte d'Azur, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275, Valbonne Sophia Antipolis, France
| | - Barbara Seitz-Polski
- Université Côte d'Azur, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275, Valbonne Sophia Antipolis, France
- Service de Néphrologie-Dialyse-Transplantation, Hôpital Pasteur, CHU de Nice, Université de Nice-Sophia Antipolis, France
- Centre de Référence Maladies Rares Syndrome Néphrotique Idiopathique, CHU de Nice, Université de Nice-Sophia Antipolis, France
- Laboratoire d'Immunologie, Hôpital l'Archet, CHU de Nice, Université de Nice-Sophia Antipolis, France
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Stahl RAK, Hoxha E. [Membranous glomerulonephritis : An example of individualized medicine in nephrology]. Internist (Berl) 2019; 60:440-449. [PMID: 30859275 DOI: 10.1007/s00108-019-0573-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Membranous glomerulonephritis (MGN) is the most frequent cause of a nephrotic syndrome in adults. It is an autoimmune disease caused by binding of autoantibodies to endogenous proteins expressed on glomerular podocytes. Antibody binding and activation of inflammatory mediators result in the onset of proteinuria. Recently, two endogenous podocytic target antigens in MGN have been characterized and their clinical role is a main focus of research in nephrology. OBJECTIVE The discovery that antibodies against phospholipase A2 receptor 1 (PLA2R1) and thrombospondin type 1 domain containing 7A (THSD7A) mediate the pathogenesis of MGN leads to the question of what clinical role these antibodies have in patients with MGN. MATERIAL AND METHODS Evidence published in recent years on the role of the described antigens is analyzed and critically discussed. The clinical conclusions derived for patients with MGN are presented. RESULTS Antibodies against PLA2R1 are detectable in approximately 80% of patients with MGN, while 2-3% of patients have antibodies against THSD7A. Serum analyses of antibodies and immunohistological staining in kidney biopsies enable an almost 100% certain diagnosis of PLA2R1 and THSD7A-mediated MGN. Serum levels of PLA2R1 antibodies are predictors for the response to therapy, determine the prognosis and allow an exact individualized monitoring of treatment. The THSD7A antibodies are associated with an increased prevalence of malignant tumors and play a pathogenetic role in the genesis of this secondary form of MGN. CONCLUSION The characterization of the antibodies responsible for the development of MGN is an example of precision medicine in nephrology and the foundation for the development of new, curative treatments.
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Affiliation(s)
- Rolf A K Stahl
- Zentrum für Innere Medizin, lll. Medizinische Klinik, Universitätsklinikum Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Deutschland.
| | - Elion Hoxha
- Zentrum für Innere Medizin, lll. Medizinische Klinik, Universitätsklinikum Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Deutschland
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Stahl RA, Reinhard L, Hoxha E. Characterization of autoantibodies in primary membranous nephropathy and their clinical significance. Expert Rev Clin Immunol 2018; 15:165-175. [PMID: 30433832 DOI: 10.1080/1744666x.2019.1548934] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Introduction: Membranous nephropathy (MN) is the most common cause of a nephrotic syndrome in Caucasian adults. The identification of target antigens in MN in the last decade has had a major impact on the clinical approach to these patients. Areas covered: Since the discoveries in animal models in the 1980s that circulating autoantibodies induce disease upon in situ binding to glomerular podocytes, many attempts have been undertaken to define the human antigens responsible for disease induction. Only in 2009 was Phospholipase A2 Receptor 1 described as the major antigen responsible for MN onset in about 70% of patients. Subsequently, in 2014, Thrombospondin Type-1 Domain-Containing 7A was identified as a second antigen, accounting for 2-3% of patients with MN. The knowledge of the role of these antibodies in MN has improved the diagnosis and management of patients and helped to better define the need for immunosuppressive treatment. Expert commentary: These discoveries over the last 10 years in the discipline of nephrology have clearly shown the improvements a better understanding of disease pathogenesis can bring for patient care.
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Affiliation(s)
- Rolf Ak Stahl
- a III. Department of Medicine , University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| | - Linda Reinhard
- a III. Department of Medicine , University Medical Center Hamburg-Eppendorf , Hamburg , Germany
| | - Elion Hoxha
- a III. Department of Medicine , University Medical Center Hamburg-Eppendorf , Hamburg , Germany
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Liu YC, Chun J. Prospects for Precision Medicine in Glomerulonephritis Treatment. Can J Kidney Health Dis 2018; 5:2054358117753617. [PMID: 29449955 PMCID: PMC5808958 DOI: 10.1177/2054358117753617] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 11/12/2017] [Indexed: 02/06/2023] Open
Abstract
Background: Glomerulonephritis (GN) consists of a group of kidney diseases that are categorized based on shared histopathological features. The current classifications for GN make it difficult to distinguish the individual variability in presentation, disease progression, and response to treatment. GN is a significant cause of end-stage renal disease (ESRD), and improved therapies are desperately needed because current immunosuppressive therapies sometimes lack efficacy and can lead to significant toxicities. In recent years, the combination of high-throughput genetic approaches and technological advances has identified important regulators contributing to GN. Objectives: In this review, we summarize recent findings in podocyte biology and advances in experimental approaches that have opened the possibility of precision medicine in GN treatment. We provide an integrative basic science and clinical overview of new developments in GN research and the discovery of potential candidates for targeted therapies in GN. Findings: Advances in podocyte biology have identified many candidates for therapeutic targets and potential biomarkers of glomerular disease. The goal of precision medicine in GN is now being pursued with recent technological improvements in genetics, accessibility of biologic and clinical information with tissue biobanks, high-throughput analysis of large-scale data sets, and new human model systems such as kidney organoids. Conclusion: With advances in data collection, technologies, and experimental model systems, we now have vast tools available to pursue precision medicine in GN. We anticipate a growing number of studies integrating data from high-throughput analysis with the development of diagnostic tools and targeted therapies for GN in the near future.
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Affiliation(s)
- Yulu Cherry Liu
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Justin Chun
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.,Division of Nephrology, Department of Medicine, University of Calgary, Alberta, Canada
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Venkatareddy M, Verma R, Kalinowski A, Patel SR, Shisheva A, Garg P. Distinct Requirements for Vacuolar Protein Sorting 34 Downstream Effector Phosphatidylinositol 3-Phosphate 5-Kinase in Podocytes Versus Proximal Tubular Cells. J Am Soc Nephrol 2016; 27:2702-19. [PMID: 26825532 DOI: 10.1681/asn.2015050555] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 12/09/2015] [Indexed: 12/16/2022] Open
Abstract
The mechanisms by which the glomerular filtration barrier prevents the loss of large macromolecules and simultaneously, maintains the filter remain poorly understood. Recent studies proposed that podocytes have an active role in both the endocytosis of filtered macromolecules and the maintenance of the filtration barrier. Deletion of a key endosomal trafficking regulator, the class 3 phosphatidylinositol (PtdIns) 3-kinase vacuolar protein sorting 34 (Vps34), in podocytes results in aberrant endosomal membrane morphology and podocyte dysfunction. We recently showed that the vacuolation phenotype in cultured Vps34-deficient podocytes is caused by the absence of a substrate for the Vps34 downstream effector PtdIns 3-phosphate 5-kinase (PIKfyve), which phosphorylates Vps34-generated PtdIns(3)P to produce PtdIns (3,5)P2. PIKfyve perturbation and PtdIns(3,5)P2 reduction result in massive membrane vacuolation along the endosomal system, but the cell-specific functions of PIKfyve in vivo remain unclear. We show here that the genetic deletion of PIKfyve in endocytically active proximal tubular cells resulted in the development of large cytoplasmic vacuoles caused by arrested endocytic traffic progression at a late-endosome stage. In contrast, deletion of PIKfyve in glomerular podocytes did not significantly alter the endosomal morphology, even in age 18-month-old mice. However, on culturing, the PIKfyve-deleted podocytes developed massive cytoplasmic vacuoles. In summary, these data suggest that glomerular podocytes and proximal tubules have different requirements for PIKfyve function, likely related to distinct in vivo needs for endocytic flux.
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Affiliation(s)
- Madhusudan Venkatareddy
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; and
| | - Rakesh Verma
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; and
| | - Anne Kalinowski
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; and
| | - Sanjeevkumar R Patel
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; and
| | - Assia Shisheva
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Puneet Garg
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; and
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11
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Li TT, Zhang XH, Jing JF, Li X, Yang XQ, Zhu FH, Tang W, Zuo JP. Artemisinin analogue SM934 ameliorates the proteinuria and renal fibrosis in rat experimental membranous nephropathy. Acta Pharmacol Sin 2015; 36:188-99. [PMID: 25619396 DOI: 10.1038/aps.2014.134] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 10/27/2014] [Indexed: 12/14/2022] Open
Abstract
AIM SM934 is a novel water-soluble artemisinin derivative with immunoregulatory activities that has been used to treat murine lupus nephritis. In the current study, we investigated the effects of SM934 on rat experimental membranous nephropathy. METHODS Passive Heymann nephritis (PHN) was induced in SD rats by intraperitoneal injection of anti-Fx1A serum. The rats were orally administered SM934 (12.5 and 25 mg·kg(-1)·d(-1)) or prednisolone (5 mg·kg(-1)·d(-1)) for 28 d. Blood and urine sample, and kidney tissue were collected for analyses. Human complement C3a-induced injury of HK-2 cells was used for in vitro experiments. RESULTS Treatment of PHN rats with SM934 or prednisolone attenuated the progression of glomerulonephritis and renal fibrosis, as evidenced by the reduced level of proteinuria and circulating antibodies, as well as by the reduced immune complex deposition, reversed podocyte injuries, and attenuated tubulointerstitial fibrosis in the kidneys. Furthermore, the two drugs suppressed TGF-β1 expression and Smad2/3 phosphorylation, and increased Smad7 expression in the kidneys. The two doses of SM934 produced almost identical therapeutic effects on PHN rats. Pretreatment with SM934 or a C3a receptor antagonist blocked the C3a-induced epithelial-mesenchymal transition in HK-2 cells in vitro. CONCLUSION SM934 ameliorates kidney injury and attenuates the tubulointerstitial fibrosis in PHN rats by down-regulation of the TGF-β1/Smad signaling pathway.
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12
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Hoxha E, Thiele I, Zahner G, Panzer U, Harendza S, Stahl RAK. Phospholipase A2 receptor autoantibodies and clinical outcome in patients with primary membranous nephropathy. J Am Soc Nephrol 2014; 25:1357-66. [PMID: 24610926 DOI: 10.1681/asn.2013040430] [Citation(s) in RCA: 230] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Membranous nephropathy (MN) is the most common cause of nephrotic syndrome in adults, with an uncertain clinical outcome. The characterization of the phospholipase A2 receptor (PLA2R) as the major target antigen in primary MN and the detection of circulating autoantibodies in these patients is a major advance in understanding this disease. To test whether PLA2R antibody levels reflect disease activity or clinical outcome, we performed a prospective multicenter study of 133 adult patients with primary MN and detectable serum PLA2R antibodies who had not received immunosuppressive therapy. Patients were followed ≤24 months. PLA2R antibody levels associated with clinical disease activity (proteinuria) in patients with immunosuppressive therapy (n=101) or supportive care (n=32). Within 3 months, immunosuppressive therapy led to a sustained 81% reduction in PLA2R antibody levels paralleled by a 39% reduction in proteinuria. Patients who experienced remission of proteinuria after 12 months had significantly lower PLA2R antibody levels at the time of study inclusion compared with patients with no remission. Patients with high PLA2R antibody levels achieved remission of proteinuria significantly later than patients with low PLA2R antibody levels. PLA2R antibody levels fell over time in patients with spontaneous remission but remained elevated in patients who did not show a reduction in proteinuria. Multivariable Cox regression analysis confirmed PLA2R antibody level as an independent risk factor for not achieving remission of proteinuria. We conclude that a decrease in PLA2R antibody level is associated with a decrease of proteinuria in patients with primary MN.
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Affiliation(s)
- Elion Hoxha
- University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ina Thiele
- University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Gunther Zahner
- University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ulf Panzer
- University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sigrid Harendza
- University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Rolf A K Stahl
- University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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13
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ISN Forefronts Symposium 2010 in Sylt, Germany: 'Induction and Resolution of Renal Inflammation'. Kidney Int 2011; 79:807-13. [PMID: 21289596 DOI: 10.1038/ki.2010.560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The International Society of Nephrology (ISN) Forefronts Symposium 'Induction and Resolution of Renal Inflammation' took place in May 2010 on the Island of Sylt, Germany. The program included basic and clinical aspects of inflammation with a special focus on human and experimental glomerulonephritis. Distinguished scientists from different fields of inflammation research reported their recent discoveries and discussed emerging topics including the role of resolution for inflammatory processes; the 'new and old' cellular players of innate immunity and their mediators; the fundamental role of T-cell subtypes and chemokines; new aspects of B cell-mediated immune responses; and finally the potential implication of results from basic science for human inflammatory renal disease.
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14
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Murtas C, Bruschi M, Carnevali ML, Petretto A, Corradini E, Prunotto M, Candiano G, degl'Innocenti ML, Ghiggeri GM, Allegri L. In vivo characterization of renal auto-antigens involved in human auto-immune diseases: The case of membranous glomerulonephritis. Proteomics Clin Appl 2011; 5:90-7. [DOI: 10.1002/prca.201000079] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Revised: 10/25/2010] [Accepted: 11/08/2010] [Indexed: 11/06/2022]
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15
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Lefevre GM, Patel SR, Kim D, Tessarollo L, Dressler GR. Altering a histone H3K4 methylation pathway in glomerular podocytes promotes a chronic disease phenotype. PLoS Genet 2010; 6:e1001142. [PMID: 21060806 PMCID: PMC2965754 DOI: 10.1371/journal.pgen.1001142] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Accepted: 09/28/2010] [Indexed: 01/27/2023] Open
Abstract
Methylation of specific lysine residues in core histone proteins is essential for embryonic development and can impart active and inactive epigenetic marks on chromatin domains. The ubiquitous nuclear protein PTIP is encoded by the Paxip1 gene and is an essential component of a histone H3 lysine 4 (H3K4) methyltransferase complex conserved in metazoans. In order to determine if PTIP and its associated complexes are necessary for maintaining stable gene expression patterns in a terminally differentiated, non-dividing cell, we conditionally deleted PTIP in glomerular podocytes in mice. Renal development and function were not impaired in young mice. However, older animals progressively exhibited proteinuria and podocyte ultra structural defects similar to chronic glomerular disease. Loss of PTIP resulted in subtle changes in gene expression patterns prior to the onset of a renal disease phenotype. Chromatin immunoprecipitation showed a loss of PTIP binding and lower H3K4 methylation at the Ntrk3 (neurotrophic tyrosine kinase receptor, type 3) locus, whose expression was significantly reduced and whose function may be essential for podocyte foot process patterning. These data demonstrate that alterations or mutations in an epigenetic regulatory pathway can alter the phenotypes of differentiated cells and lead to a chronic disease state. While all cells contain essentially the same genome, adult differentiated cells have specific patterns of gene expression for unique physiological functions. Gene expression depends on specific proteins that activate some genes and repress others so that a stable pattern of expression is maintained. During embryonic development, epigenetic modifications of the genome may compartmentalize the genome into actively expressed or repressed domains through the methylation of specific histone residues on chromatin. We studied a specific pathway of histone H3 lysine 4 methylation by deleting the co-factor PTIP in a differentiated cell type. We then asked whether this epigenetic pathway is still important for maintaining the correct pattern of gene expression. Using the podocyte cells of the glomerulus as a model system, mice that carry deletions of the PTIP protein only in these podocytes show changes in gene expression patterns over time and exhibit a slowly progressing chronic disease phenotype. Chromatin immunoprecipitation showed a loss of PTIP binding and lower H3K4 methylation at the Ntrk3 locus, whose expression was significantly reduced. These data demonstrate the need for maintaining the correct epigenetic pattern in an aging, differentiated cell type and point to modifications in epigenetics as potential disease causing factors.
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Affiliation(s)
- Gaelle M. Lefevre
- Department of Pathology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Sanjeevkumar R. Patel
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Doyeob Kim
- Department of Pathology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Lino Tessarollo
- Neural Development Section, National Cancer Institute, Frederick, Maryland, United States of America
| | - Gregory R. Dressler
- Department of Pathology, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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16
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Triptolide reduces proteinuria in experimental membranous nephropathy and protects against C5b-9-induced podocyte injury in vitro. Kidney Int 2010; 77:974-88. [DOI: 10.1038/ki.2010.41] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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17
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Hauser PV, Perco P, Mühlberger I, Pippin J, Blonski M, Mayer B, Alpers CE, Oberbauer R, Shankland SJ. Microarray and bioinformatics analysis of gene expression in experimental membranous nephropathy. Nephron Clin Pract 2009; 112:e43-58. [PMID: 19390219 DOI: 10.1159/000213505] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Accepted: 01/12/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Passive Heymann nephritis (PHN), the best characterized animal model of experimental membranous nephropathy, is characterized by subepithelial immune deposits, podocyte foot processes effacement and massive proteinuria beginning 4 days following disease induction. Although single genes involved in PHN have been studied, no whole genome-wide expression analysis of kidney tissue has been performed. METHODS Microarray analysis was performed to identify gene expression changes in PHN rat kidneys during the onset of proteinuria. RESULTS Our results showed that 234 transcripts were differentially expressed in diseased animals compared to controls. Genes exclusively upregulated in diseased animals were mainly required for cell structure and motility, immunity and defense, cell cycle, and developmental processes. The single most increased gene was transgelin (Tagln) showing a 70-fold upregulation in animals with PHN. Protein-protein interaction analysis revealed the following four processes of major relevance in disease manifestation: (i) DNA damage and repair; (ii) changes in the extracellular matrix; (iii) deregulation of cytokines and growth factors, as well as (iv) rearrangements of the cytoskeleton. CONCLUSION We show for the first time the complex interplay between multiple different genes in experimental membranous nephropathy, supporting a role for genomic approaches to better understanding and defining specific disease processes.
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Affiliation(s)
- Peter V Hauser
- Division of Nephrology & Hypertension, University of Washington School of Medicine, Seattle, Wash. 98195, USA.
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Nishi H, Inagi R, Kato H, Tanemoto M, Kojima I, Son D, Fujita T, Nangaku M. Hemoglobin is expressed by mesangial cells and reduces oxidant stress. J Am Soc Nephrol 2008; 19:1500-8. [PMID: 18448584 DOI: 10.1681/asn.2007101085] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Hemoglobin (Hb) serves as the main oxygen transporter in erythrocytes, but it is also expressed in nonhematopoietic organs, where it serves an unknown function. In this study, microarray and proteomic analyses demonstrated Hb expression in the kidney. Rat kidneys were perfused extensively with saline, and glomeruli were isolated by several techniques (sieving, manual dissection, and laser capture-microdissection). Reverse transcriptase-PCR revealed glomerular alpha- and beta-globin expression, and immunoblotting demonstrated expression of the protein. In situ hybridization studies showed expression of the globin subunits in the mesangium, and immunostaining confirmed this localization of Hb. Furthermore, globin mRNA expression was detected in primary cultures of rat mesangial cells but not in cultured glomerular endothelial or epithelial cells. For investigation of Hb function in mesangial cells, the SV40-MES13 murine mesangial cell line was transfected with a vector expressing alpha- and beta-globins; this overexpression reduced production of hydrogen peroxide-induced intracellular radical oxygen species and enhanced cell viability against oxidative stress. In summary, Hb is expressed by rat mesangial cells, and its potential functions may include antioxidative defense.
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Affiliation(s)
- Hiroshi Nishi
- Division of Nephrology and Endocrinology, University of Tokyo School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan
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19
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Candiano G, Musante L, Bruschi M, Petretto A, Santucci L, Del Boccio P, Pavone B, Perfumo F, Urbani A, Scolari F, Ghiggeri GM. Repetitive fragmentation products of albumin and alpha1-antitrypsin in glomerular diseases associated with nephrotic syndrome. J Am Soc Nephrol 2006; 17:3139-48. [PMID: 17005933 DOI: 10.1681/asn.2006050486] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Even if nephrotic syndrome is characterized by massive urinary loss of major plasma proteins, a clear structural characterization based on proteomics has never been reported. Urine and plasma of 23 patients with different idiopathic nephrotic syndromes (10 steroid-sensitive minimal-change nephropathy, seven steroid-resistant FSGS, and six membranous glomerulonephritis) were analyzed with two-dimensional electrophoresis in soft gel, Western blot, and matrix-assisted laser desorption/ionization time of flight mass spectrometry; 72 urinary components corresponded to fragments of albumin and/or of alpha1-antitrypsin. Several repetitive fragmentation motives and a few differences among different pathologies were found. Several (21 of 72) urinary albumin fragments also were detected in plasma, although in lower concentration, suggesting a preferential excretion. The bulk of components with low molecular weight were detected only in urine, suggesting an in situ formation; zymograms with albumin as substrate showed the presence in urine of specific proteases. A final but not secondary point was the characterization of albumin adducts that harbor both the COOH and NH2 terminal parts of the protein, suggesting the formation of new covalent chemical groups. Altogether, these new findings reveal unexpected structural and functional aspects of proteinuria that may play a key role in pathogenesis. Characterization of urinary fragmentation patterns should be extended to other renal diseases.
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Affiliation(s)
- Giovanni Candiano
- Laboratory on Pathophysiology of Uremia, G. Gaslini Children Hospital, Genova, Italy
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20
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Rastaldi MP, Candiano G, Musante L, Bruschi M, Armelloni S, Rimoldi L, Tardanico R, Sanna-Cherchi S, Cherchi SS, Ferrario F, Montinaro V, Haupt R, Parodi S, Carnevali ML, Allegri L, Camussi G, Gesualdo L, Scolari F, Ghiggeri GM. Glomerular clusterin is associated with PKC-alpha/beta regulation and good outcome of membranous glomerulonephritis in humans. Kidney Int 2006; 70:477-85. [PMID: 16775601 DOI: 10.1038/sj.ki.5001563] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Mechanisms for human membranous glomerulonephritis (MGN) remain elusive. Most up-to-date concepts still rely on the rat model of Passive Heymann Nephritis that derives from an autoimmune response to glomerular megalin, with complement activation and membrane attack complex assembly. Clusterin has been reported as a megalin ligand in immunodeposits, although its role has not been clarified. We studied renal biopsies of 60 MGN patients by immunohistochemistry utilizing antibodies against clusterin, C5b-9, and phosphorylated-protien kinase C (PKC) isoforms (pPKC). In vitro experiments were performed to investigate the role of clusterin during podocyte damage by MGN serum and define clusterin binding to human podocytes, where megalin is known to be absent. Clusterin, C5b-9, and pPKC-alpha/beta showed highly variable glomerular staining, where high clusterin profiles were inversely correlated to C5b-9 and PKC-alpha/beta expression (P=0.029), and co-localized with the low-density lipoprotein receptor (LDL-R). Glomerular clusterin emerged as the single factor influencing proteinuria at multivariate analysis and was associated with a reduction of proteinuria after a follow-up of 1.5 years (-88.1%, P=0.027). Incubation of podocytes with MGN sera determined strong upregulation of pPKC-alpha/beta that was reverted by pre-incubation with clusterin, serum de-complementation, or protein-A treatment. Preliminary in vitro experiments showed podocyte binding of biotinilated clusterin, co-localization with LDL-R and specific binding inhibition with anti-LDL-R antibodies and with specific ligands. These data suggest a central role for glomerular clusterin in MGN as a modulator of inflammation that potentially influences the clinical outcome. Binding of clusterin to the LDL-R might offer an interpretative key for the pathogenesis of MGN in humans.
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Affiliation(s)
- M P Rastaldi
- Renal Immunopathology Laboratory, Fondazione D'Amico per la Ricerca sulle Malattie Renali, Nuova Nefrologia Research Association, c/o San Carlo Borromeo Hospital, Milan, Italy
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Inagi R, Nangaku M, Onogi H, Ueyama H, Kitao Y, Nakazato K, Ogawa S, Kurokawa K, Couser WG, Miyata T. Involvement of endoplasmic reticulum (ER) stress in podocyte injury induced by excessive protein accumulation. Kidney Int 2005; 68:2639-50. [PMID: 16316340 DOI: 10.1111/j.1523-1755.2005.00736.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND An imbalance between protein load and folding capacity is referred to as endoplasmic reticulum (ER) stress. As a defense mechanism, cells express ER stress inducible chaperons, such as oxygen-regulated proteins 150 (ORP150) and glucose-regulated proteins (GRPs). While ER stress is important in various diseases, a pathophysiologic role for ER stress in kidney disease remains elusive. Here we investigate expression of ER stress proteins in cultured rat podocytes as well as in our recently developed animal model of abnormal protein retention within the ER of podocytes (i.e., megsin transgenic rat). METHODS The expression of ER stress inducible proteins (ORP150, GRP78, or GRP94) in cultured podocytes treated with tunicamycin, A23187, SNAP, hypoxia, or hyperglycemia, and the renal tissues or isolated glomeruli from megsin transgenic rats was analyzed by Western blotting analysis, immunohistochemistry, or confocal microscopy. RESULTS Cultured podocytes demonstrated that treatment with tunicamycin, A23187, and SNAP, but not hypoxia or hyperglycemia, up-regulate expression of ER stress proteins. Extracts of isolated glomeruli from megsin transgenic rats reveal marked up-regulation of ER stress chaperones in podocytes, which was supported by immunohistochemical analysis. Confocal microscopy revealed that ER stress in podocytes was associated with cellular injury. Podocytes of transgenic rats overexpressing a mutant megsin, without the capacity for polymerization within the ER, do not exhibit ER stress or podocyte damage, suggesting a pathogenic role of ER retention of polymerized megsin. CONCLUSION This paper implicates a crucial role for the accumulation of excessive proteins in the podocyte ER in the induction of ER stress and associated podocyte injury.
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Affiliation(s)
- Reiko Inagi
- Molecular and Cellular Nephrology, Institute of Medical Sciences, Tokai University, Kanagawa, Japan
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Milovanceva-Popovska M, Kunter U, Ostendorf T, Petermann A, Rong S, Eitner F, Kerjaschki D, Barnett A, Floege J. R-roscovitine (CYC202) alleviates renal cell proliferation in nephritis without aggravating podocyte injury. Kidney Int 2005; 67:1362-70. [PMID: 15780088 DOI: 10.1111/j.1523-1755.2005.00213.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Cyclin-dependent kinase (CDK) inhibition is a new therapeutic approach to proliferative glomerulonephritides. CDK2 is required for G(1)/S transition and DNA synthesis and is inhibited by CYC202 (R-roscovitine). Since podocytes express CDK2 in nephritis and since loss of podocytes contributes to glomerulosclerosis, the rationale of the present study was to test whether CDK2 inhibition is safe in instances of podocyte injury. METHODS Rats with passive Heymann nephritis, a model of membranous glomerulonephritis, were treated (day 3 to 30) with vehicle, low (25 mg/kg/day), or high (50 mg/kg/day) doses of CYC202. RESULTS On day 27, blood pressure was normal in nephritic controls and was dose-dependently reduced by CYC202. Urinary albumin excretion did not differ between the groups on days 9, 16, 23, and 30. To investigate podocyte injury, we assessed the glomerular de novo expression of desmin, which was markedly up-regulated in almost all passive Heymann nephritis glomeruli but was not significantly different between the three groups. No tubulointerstitial de novo expression of desmin or alpha-smooth muscle actin (alpha-SMA), or tubulointerstitial monocyte/macrophage infiltration was noted in any group. Biologic activity of CYC202 was evident in the form of a dose-dependent decrease in the number of glomerular and tubulointerstitial mitotic figures as compared to vehicle alone. Glomerular immunostaining for cyclin D1, a marker for G(0) to G(1) transition, was significantly decreased in CYC202 treated groups at day 9. CONCLUSION Whereas inhibition of CDKs by CYC202 reduced intrarenal cell proliferation in passive Heymann nephritis it did not aggravate podocyte damage, suggesting that this novel therapeutic approach is safe in renal diseases characterized by podocyte injury.
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Nagahama K, Maru K, Kanzaki S, Chai HL, Nakai T, Miura S, Yamaguchi A, Yamanaka S, Nagashima Y, Aoki I. Possible role of autoantibodies against nephrin in an experimental model of chronic graft-versus-host disease. Clin Exp Immunol 2005; 141:215-22. [PMID: 15996185 PMCID: PMC1809431 DOI: 10.1111/j.1365-2249.2005.02838.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Nephrin, a product of the NPHS1 gene, is a component of the slit diaphragms that are found between glomerular foot processes and is a crucial element for glomerular filtration barrier. Recently, nephrin has been focused in a number of studies of proteinuria development including various types of acquired glomerular diseases including minimal change nephrotic syndrome and membranous nephropathy. However, the precise role of nephrin in such acquired glomerular diseases is still unknown. To analyse the role of nephrin further, two kinds of anti-nephrin antibodies were raised in the rabbits and applied to an experimental mouse model of chronic graft-versus-host disease, in which (C57BL/10 x DBA/2) F1 mice developed clinically apparent severe proteinuria with significant glomerular lesions 7 weeks after parental DBA/2 cell transfer. Antibody-sandwich ELISA detected anti-nephrin antibodies during week 2 to week 6, with the peak at week 2 or week 4. Colocalization of nephrin and IgG on week 4, week 6, and week 8 was revealed by confocal microscopic analysis, suggesting that in situ immune complex formation with nephrin in glomerular lesion. Taken together, it seems to be suggested nephrin and its autoantibody have a certain role in the development of glomerular lesion in our model mice.
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Affiliation(s)
- K Nagahama
- Department of Pathology, Yokohama City University School of Medicine, Kanagawa 236-0004, Japan
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Blume C, Heise G, Hess A, Waldner C, Grabensee B, Schroer K, Heering P. Different effect of cyclosporine A and mycophenolate mofetil on passive Heymann nephritis in the rat. Nephron Clin Pract 2005; 100:e104-12. [PMID: 15855806 DOI: 10.1159/000085029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2004] [Accepted: 09/29/2004] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND While cyclosporine A (CsA) is an effective therapy for nephrotic syndrome, it has nephrotoxic side effects. We compared the anti-proteinuric effects and nephrotoxicity in rats with passive Heymann nephritis (PHN) of CsA and mycophenolate mofetil (MMF). METHODS PHN was induced in female Wistar rats. Two treatment groups consisting of 8 rats each received either 25 mg of CsA or 25 mg of MMF/kg body weight/day and were compared with untreated controls. Kidney function and proteinuria were monitored over 4 weeks. Western blots were used for densitometric analysis of renal cyclooxygenase-2 (COX-2) protein expression. Thromboxane B2 (TxB2) and 6-keto-PGF(1alpha) were determined by radioimmunoassays (RIAs) in renal tissue and urine. RESULTS Rats with PHN exhibited a marked proteinuria of 12.76 +/- 4.42 vs. 0.73 +/- 0.28 mg/24 h (p < 0.01) and showed increased glomerular concentrations of TxB2 and 6-keto-PGF(1alpha) (992.6 +/- 216.9 and 1,187.0 +/- 54.2 pg/mg protein, respectively) compared with healthy controls (595 +/- 196.17 and 729 +/- 297.84, respectively) and a strongly induced COX-2 protein expression. CsA and MMF treatment reduced PHN-related proteinuria to 2.10 +/- 1.47 and 1.47 +/- 7.2 mg/24 h, respectively. In rats with PHN, CsA induced a significant deterioration of renal function and enhanced urine excretion of thromboxane A2, paralleled by a significant, twofold increase in COX-2 protein expression and renal prostaglandins. By contrast, MMF treatment in rats with PHN was not nephrotoxic and had no effect on prostaglandin production. COX-2 protein expression under MMF was suppressed. CONCLUSION While the antiproteinuric efficacy of MMF and CsA in PHN was comparable, the absence of nephrotoxicity might favor MMF in the treatment of nephrotic syndrome. The CsA-induced increase in COX-2 expression and COX-2-dependent prostacyclin may indicate a mechanism that compensates nephrotoxicity in the diseased and CsA-exposed kidney.
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Affiliation(s)
- Cornelia Blume
- Klinik fur Nephrologie und Rheumatologie, Dusseldorf, Deutschland.
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Cunningham PN, Quigg RJ. Contrasting roles of complement activation and its regulation in membranous nephropathy. J Am Soc Nephrol 2005; 16:1214-22. [PMID: 15800113 DOI: 10.1681/asn.2005010096] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The complement system is involved in defense against microorganisms, the processing of immune complexes and apoptotic debris, and the development of an appropriate immune response. Along with these physiologic effects, complement activation has the potential to result in tissue pathology. To limit this, various complement regulatory proteins (CRP) are present on host cells, including the glomerular podocyte. Experimental data from the Heymann nephritis (HN) rat model of human membranous nephropathy (MN) have shown that IgG antibodies in subepithelial immune deposits initiate complement activation and C5b-9-mediated damage of the overlying podocyte. Although IgG can activate the classical pathway, there also is evidence that alternative pathway activation occurs in MN, which could occur because of absent, dysfunctional, or inhibited podocyte CRP. Related to this are experimental data in HN showing the presence of antibodies that bind and inhibit podocyte CRP; although such antibodies have not been documented in human MN, a decrease in CR1 quantity on the podocyte has been observed. A s a result of a relative lack of CRP and the exposure of activating complement proteins to tubular cells, alternative complement pathway activation and C5b-9-mediated tubular injury can occur in MN and other proteinuric diseases. Overall, in a disease such as MN, the balance between complement regulation and activation is tipped toward its being activated. Therefore, a number of therapeutic approaches have been developed to counteract this, including recombinant forms of endogenous CRP and complement-inhibitory monoclonal antibodies. There is good reason to be optimistic that approaches to block complement activation will become viable therapy for human MN in the future.
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Affiliation(s)
- Patrick N Cunningham
- Section of Nephrology, The University of Chicago, AMB-S523, MC 5100, 5841 South Maryland Avenue, Chicago, IL 60637, USA
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Fujita Y, Maruyama S, Kogo H, Matsuo S, Fujimoto T. Caveolin-1 in mesangial cells suppresses MAP kinase activation and cell proliferation induced by bFGF and PDGF. Kidney Int 2004; 66:1794-804. [PMID: 15496150 DOI: 10.1111/j.1523-1755.2004.00954.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Caveolin is a principal component of caveolae and regulates signaling in caveolae. Mesangial cells contain many caveolae, and thus manipulation of caveolin-1 expression level might be useful to control mesangial cell proliferation, which is an important aggravating factor in many renal diseases. METHODS In the present study, we transfected caveolin-1 cDNA to rat primary mesangial cells and MES13 cells, and examined the effects on Raf-extracellular signal-regulated protein kinase (ERK) kinase (MEK)-mitogen-activated protein (MAP) kinase pathway and cell proliferation stimulated by basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF). Activity of the kinases was analyzed by immunofluorescence labeling and Western blot analysis. RESULTS The overexpression of caveolin-1 inhibited the activation of Raf-1, MEK-1/2, and MAP kinase induced by either bFGF or PDGF. Furthermore, it suppressed the cell proliferation caused by the cytokines. The effect was specific to the Raf-MEK-MAP kinase pathway, because it did not influence activation of Smad2 induced by transforming growth factor-beta (TGF-beta). On the contrary, expression of a dominant-negative caveolin mutant, DGV-caveolin, augmented activation of MAP kinase. CONCLUSION The result showed that overexpression of caveolin-1 in mesangial cells suppresses MAP kinase activation and cell proliferation induced by bFGF and PDGF. Because bFGF and PDGF are two major cytokines involved in the mesangioproliferative nephritis, the result implies that introduction of caveolin-1 expression vector is a potential therapeutic tool for the disease.
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Affiliation(s)
- Yutaka Fujita
- Division of Clinical Immunology, Department of Internal Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan.
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Griffin SV, Pichler R, Wada T, Vaughan M, Durvasula R, Shankland SJ. The role of cell cycle proteins in Glomerular disease. Semin Nephrol 2004; 23:569-82. [PMID: 14631565 DOI: 10.1053/s0270-9295(03)00133-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Although initially identified and characterized as regulators of the cell cycle and hence proliferation, an extended role for cell cycle proteins has been appreciated more recently in a number of physiologic and pathologic processes, including development, differentiation, hypertrophy, and apoptosis. Their precise contribution to the cellular response to injury appears to be dependent on both the cell type and the nature of the initiating injury. The glomerulus offers a remarkable situation in which to study the cell cycle proteins, as each of the 3 major resident cell types (the mesangial cell, podocyte, and glomerular endothelial cell) has a specific pattern of cell cycle protein expression when quiescent and responds uniquely after injury. Defining their roles may lead to potential therapeutic strategies in glomerular disease.
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Affiliation(s)
- Siân V Griffin
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
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Ren G, Doshi M, Hack BK, Alexander JJ, Quigg RJ. Rat glomerular epithelial cells produce and bear factor H on their surface that is up-regulated under complement attack. Kidney Int 2003; 64:914-22. [PMID: 12911541 DOI: 10.1046/j.1523-1755.2003.00188.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Factor H is a potent complement inhibitory molecule that is primarily produced by the liver and appears in plasma as a soluble protein. Yet there is evidence that other cells, including those in the kidney, can produce factor H, and that it can be cell-associated as well as present as a plasma protein. Here we studied factor H in rat glomerular epithelial cells (GEC). METHODS A polyclonal antibody to factor H was used to identify factor H protein. A polymerase chain reaction (PCR)-based strategy was utilized to clone the full-length cDNA of GEC factor H. The relative quantity of factor H mRNA was measured by quantitative reverse transcription (RT)-PCR in cultured GEC exposed to complement activation and in the passive Heymann nephritis (PHN) model of membranous nephropathy. RESULTS By immunofluorescence microscopy, factor H protein was present on the plasma membranes of cultured GEC. Based upon Western blot studies, this appeared to be the full-length 150 kD factor H protein. Factor H cDNA cloned from GEC was identical to the newly deposited sequence for rat liver factor H cDNA. In cultured GEC in which complement was activated, factor H mRNA increased over time. Similarly, in the PHN model in which complement was activated on GEC in vivo, factor H mRNA and protein also increased over time. CONCLUSION Cultured GEC and glomeruli express factor H mRNA and protein. As modeled both in vitro and in vivo in the rat, factor H is up-regulated in membranous nephropathy. This is likely to be a direct response of GEC to complement attack and may represent a protective response of this cell.
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Affiliation(s)
- Guohui Ren
- Section of Nephrology, The University of Chicago, Chicago, Illinois, USA
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Barletta GM, Kovari IA, Verma RK, Kerjaschki D, Holzman LB. Nephrin and Neph1 co-localize at the podocyte foot process intercellular junction and form cis hetero-oligomers. J Biol Chem 2003; 278:19266-71. [PMID: 12646566 DOI: 10.1074/jbc.m301279200] [Citation(s) in RCA: 141] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Glomerular visceral epithelial cells (podocytes) appear to play a central role in maintaining the selective filtration barrier of the renal glomerulus. While the immunoglobulin superfamily member Nephrin was proposed to act as a cell adhesion molecule at the podocyte intercellular junction necessary for maintaining glomerular perm selectivity, the Nephrin ligand has not been identified. The existence of a new subfamily of Nephrin-like molecules including Neph1 was recently described. Genetic deletion of Nephrin or Neph1 resulted in similar phenotypes of podocyte foot process effacement and proteinuria. The subcellular localization of Neph1 and the possibility that Nephrin and Neph1 interact was investigated. Polyclonal antiserum for Neph1 was raised and characterized. Neph1 migrated as a 90-kDa protein on SDS-PAGE under reducing conditions. Neph1 was identified in a glomerular and podocyte-specific distribution in adult rat kidney. Like Nephrin and Podocin, Neph1 was enriched in Triton X-100 detergent-resistant membrane fractions. Consistent with this observation, immunogold electron microscopy demonstrated that Neph1 localized exclusively to lateral margins of podocyte foot processes at the insertion of the slit diaphragm. Neph1 and Nephrin participate in a direct cis-interaction involving their cytoplasmic domains. In addition, interactions between the extracellular domain of Nephrin and itself and between the extracellular domain of Nephrin and that of Neph1 were detected. Neph1 did not interact via a homophilic interaction. These observations suggest that Nephrin and Neph1 form a hetero-oligomeric receptor complex in the plane of the membrane that might interact across the foot process intercellular junction through interactions between Nephrin with itself and Neph1.
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Affiliation(s)
- Gina-Marie Barletta
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, Michigan 48109-0676,USA
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Johnson ACM, Yabu JM, Hanson S, Shah VO, Zager RA. Experimental glomerulopathy alters renal cortical cholesterol, SR-B1, ABCA1, and HMG CoA reductase expression. THE AMERICAN JOURNAL OF PATHOLOGY 2003; 162:283-91. [PMID: 12507911 PMCID: PMC1851117 DOI: 10.1016/s0002-9440(10)63819-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/30/2002] [Indexed: 11/16/2022]
Abstract
Previous studies indicate that acute tubular injury causes free cholesterol (FC) and cholesteryl ester (CE) accumulation within renal cortex/proximal tubules. This study assessed whether similar changes occur with glomerulopathy/nephrotic syndrome, in which high-circulating/filtered lipoprotein levels increase renal cholesterol supply. Potential adaptive changes in cholesterol synthetic/transport proteins were also assessed. Nephrotoxic serum (NTS) or passive Heymann nephritis (PHN) was induced in Sprague-Dawley rats. Renal injury (blood urea nitrogen, proteinuria) was assessed 2 and 7 days (NTS), or 10 and 30 days (PHN) later. FC and CE levels in renal cortex, isolated glomeruli, and proximal tubule segments were determined. SR-B1 (a CE influx protein), ABCA1 (a FC exporter), and HMG CoA reductase protein/mRNA levels were also assessed. FC was minimally elevated in renal cortex (0 to 15%), the majority apparently localizing to proximal tubules. More dramatic CE elevations were found ( approximately 5 to 15x), correlating with the severity of proteinuria at any single time point (r >/= 0.85). Cholesterol increments were associated with decreased SR-B1, increased ABCA1, and increased HMG CoA reductase (HMGCR) protein and its mRNA. Tubule (HK-2) cell culture data indicated that SR-B1 and ABCA1 levels are responsive to cholesterol supply. Experimental nephropathy can increase renal FC, and particularly CE, levels, most notably in proximal tubules. These changes are associated with adaptations in SR-B1 and ABCA1 expression, which are physiologically appropriate changes for a cholesterol overload state. However, HMGCR protein/mRNA increments can also result. These seem to reflect a maladaptive response, potentially contributing to a cell cholesterol overload state.
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MESH Headings
- ATP Binding Cassette Transporter 1
- ATP-Binding Cassette Transporters/metabolism
- Animals
- Blotting, Western
- CD36 Antigens/metabolism
- Cell Line
- Cholesterol/metabolism
- Cholesterol Esters/metabolism
- Disease Models, Animal
- Disease Progression
- Glomerulonephritis/metabolism
- Glomerulonephritis/pathology
- Humans
- Hydroxymethylglutaryl CoA Reductases/genetics
- Hydroxymethylglutaryl CoA Reductases/metabolism
- Kidney Cortex/metabolism
- Kidney Cortex/pathology
- Kidney Function Tests
- Kidney Tubules, Proximal/cytology
- Kidney Tubules, Proximal/metabolism
- Male
- Membrane Proteins
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Immunologic
- Receptors, Lipoprotein
- Receptors, Scavenger
- Scavenger Receptors, Class B
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Affiliation(s)
- Ali C M Johnson
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
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Ren G, Doshi M, Hack BK, Alexander JJ, Quigg RJ. Isolation and characterization of a novel rat factor H-related protein that is up-regulated in glomeruli under complement attack. J Biol Chem 2002; 277:48351-8. [PMID: 12374811 DOI: 10.1074/jbc.m205135200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The factor H family in humans is composed of seven distinct proteins, including factor H-related proteins (FHR) 1-5. All members contain tandemly arranged short consensus repeats (SCR) typical of the regulators of complement activation gene family. FHR-5 is unusual for this group of proteins, as it was initially identified as a component of immune deposits in glomerular diseases. During our cloning of the cDNA for rat factor H from glomerular epithelial cells (GEC), we identified an alternative 2729-bp cDNA transcript. The translated sequence encoded a protein containing 11 SCRs, most similar to SCRs 7-15 and 19-20 in native rat factor H, which is the same basic structure of human FHR-5. As such, this rat protein was termed FHR. Recombinant rat FHR produced in a eukaryotic expression system had a molecular mass of 78 kDa. In functional studies, recombinant FHR bound C3b and inhibited the complement alternative pathway in a dose-dependent fashion. Given the prominent expression of FHR-5 in human membranous nephropathy, a disease in which complement activation occurs in the vicinity of GEC, the expression of FHR in a rat model of this disease was evaluated. In both in vitro and in vivo models of complement activation on the GEC, FHR mRNA was up-regulated by a factor of 3-6-fold compared with controls in which complement could not be activated. Thus, we have identified a novel factor H family member in rats. This FHR protein is analogous to human FHR-5, both in structure and in potential involvement in glomerular immune complex diseases.
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Affiliation(s)
- Guohui Ren
- Section of Nephrology, Department of Medicine, the University of Chicago, Illinois 60637, USA
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Bao L, Spiller OB, St John PL, Haas M, Hack BK, Ren G, Cunningham PN, Doshi M, Abrahamson DR, Morgan BP, Quigg RJ. Decay-accelerating factor expression in the rat kidney is restricted to the apical surface of podocytes. Kidney Int 2002; 62:2010-21. [PMID: 12427125 DOI: 10.1046/j.1523-1755.2002.t01-1-00652.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Decay-accelerating factor (DAF) has inhibitory activity toward complement C3 and C5 convertases. DAF is present in human glomeruli and on cultured human glomerular visceral epithelial cells (GEC). We studied the distribution and function of rat DAF. METHODS Function-neutralizing antibodies (Abs) were raised against DAF. The distribution of DAF in vivo was determined by immunoelectron microscopy. Functional studies were performed in cultured GEC and following IV injection of anti-DAF Abs into rats. RESULTS DAF was present exclusively on the apical surfaces of GEC, and was not present on the basal surfaces of GEC, nor other glomerular or kidney cells. DAF was functionally active on cultured GEC, and served to limit complement activation in concert with CD59, an inhibitor of C5b-9 formation. Upon injection into normal rats, anti-DAF F(ab')2 Abs bound to GEC in vivo, yet there was no evidence for complement activation and animals did not develop abnormal albuminuria. Anti-megalin complement-activating IgG Abs were "planted" on GEC, which activated complement as evidenced by the presence of C3d on GEC. Attempts to inhibit DAF function with anti-DAF Abs did not affect the quantity of complement activation by these anti-megalin Abs, nor did it lead to development of abnormal albuminuria. In contrast, in the puromycin aminonucleoside model of GEC injury and proteinuria, anti-DAF Abs slowed the recovery from renal failure that occurs in this model. CONCLUSION In cultured rat GEC, DAF is an effective complement regulator. In vivo, DAF is present on GEC apical surfaces. Yet, it appears that DAF is not essential to prevent complement activation from occurring under normal circumstances and in those cases in which complement-activating Abs are present on the basal surfaces of GEC in vivo. However, in proteinuric conditions, DAF appears to be protective to GEC.
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Affiliation(s)
- Lihua Bao
- Section of Nephrology, The University of Chicago, Chicago, Illinois 60637, USA.
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Eitner F, Ostendorf T, Van Roeyen C, Kitahara M, Li X, Aase K, Gröne HJ, Eriksson U, Floege J. Expression of a novel PDGF isoform, PDGF-C, in normal and diseased rat kidney. J Am Soc Nephrol 2002; 13:910-917. [PMID: 11912250 DOI: 10.1681/asn.v134910] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Platelet-derived growth factor-C (PDGF-C) is a new member of the PDGF family. Its expression in normal and diseased kidney is unknown. Rabbit antisera were generated against human full-length, core domain, and mouse PDGF-C, and their specificity was confirmed by Western blot analyses. Renal PDGF-C expression was analyzed by immunohistochemistry in normal rats (n = 8), mesangioproliferative anti-Thy 1.1 nephritis (n = 4 each at days 1, 4, 6, and 85), passive Heymann nephritis (PHN, n = 4), puromycin nephrosis (PAN, n = 2), Milan normotensive rats (MN, n = 2), and obese Zucker rats (n = 3). PDGF-C expression was also studied in anti-Thy 1.1 rats treated with PDGF-B aptamer antagonists (n = 5) or irrelevant control aptamers (n = 5). PDGF-C was constitutively expressed in arterial smooth muscle cells and collecting duct epithelial cells. Mesangial PDGF-C was markedly upregulated in anti-Thy 1.1 nephritis in parallel with the peak mesangial cell proliferation. Furthermore, PDGF-CC acted as a potent growth factor for mesangial cells in vitro. Inhibition of PDGF-B via specific aptamers reduced the injury in anti-Thy 1.1 nephritis but did not affect the glomerular PDGF-C overexpression or the mitogenicity of PDGF-CC in vitro. In PHN, PAN, and obese Zucker rats, glomeruli remained negative for PDGF-C despite severe glomerular injury. PDGF-C localized to podocytes at sites of focal and segmental sclerosis in MN. Interstitial PDGF-C expression was increased at sites of fibrosing injury in obese Zucker rats. The use of the different antisera resulted in virtually identical findings. It is concluded that PDGF-C is a novel mesangial cell mitogen that is constitutively expressed in the kidney and specifically upregulated in mesangial, visceral epithelial, and interstitial cells after predominant injury to these cells. PDGF-C may therefore be involved in the pathogenesis of renal scarring.
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Affiliation(s)
- Frank Eitner
- *Division of Nephrology and Immunology, University of Aachen, Aachen, Germany; †Ludwig Institute for Cancer Research, Stockholm, Sweden; and ‡German Cancer Research Institute, DKFZ Heidelberg, Germany
| | - Tammo Ostendorf
- *Division of Nephrology and Immunology, University of Aachen, Aachen, Germany; †Ludwig Institute for Cancer Research, Stockholm, Sweden; and ‡German Cancer Research Institute, DKFZ Heidelberg, Germany
| | - Claudia Van Roeyen
- *Division of Nephrology and Immunology, University of Aachen, Aachen, Germany; †Ludwig Institute for Cancer Research, Stockholm, Sweden; and ‡German Cancer Research Institute, DKFZ Heidelberg, Germany
| | - Masashi Kitahara
- *Division of Nephrology and Immunology, University of Aachen, Aachen, Germany; †Ludwig Institute for Cancer Research, Stockholm, Sweden; and ‡German Cancer Research Institute, DKFZ Heidelberg, Germany
| | - Xuri Li
- *Division of Nephrology and Immunology, University of Aachen, Aachen, Germany; †Ludwig Institute for Cancer Research, Stockholm, Sweden; and ‡German Cancer Research Institute, DKFZ Heidelberg, Germany
| | - Karin Aase
- *Division of Nephrology and Immunology, University of Aachen, Aachen, Germany; †Ludwig Institute for Cancer Research, Stockholm, Sweden; and ‡German Cancer Research Institute, DKFZ Heidelberg, Germany
| | - Hermann-Josef Gröne
- *Division of Nephrology and Immunology, University of Aachen, Aachen, Germany; †Ludwig Institute for Cancer Research, Stockholm, Sweden; and ‡German Cancer Research Institute, DKFZ Heidelberg, Germany
| | - Ulf Eriksson
- *Division of Nephrology and Immunology, University of Aachen, Aachen, Germany; †Ludwig Institute for Cancer Research, Stockholm, Sweden; and ‡German Cancer Research Institute, DKFZ Heidelberg, Germany
| | - Jürgen Floege
- *Division of Nephrology and Immunology, University of Aachen, Aachen, Germany; †Ludwig Institute for Cancer Research, Stockholm, Sweden; and ‡German Cancer Research Institute, DKFZ Heidelberg, Germany
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Yuan H, Takeuchi E, Taylor GA, McLaughlin M, Brown D, Salant DJ. Nephrin dissociates from actin, and its expression is reduced in early experimental membranous nephropathy. J Am Soc Nephrol 2002; 13:946-956. [PMID: 11912254 DOI: 10.1681/asn.v134946] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
These studies examined the expression of the podocyte slit diaphragm protein nephrin and its association with actin at the onset of proteinuria in passive Heymann nephritis (PHN), a rat model of human membranous nephropathy. Four days after immunization, 58% of PHN rats had mild proteinuria. At that time, most slit diaphragms were still visible on electron microscopy; however, in those locations where the deposits encroached on the filtration slits, the slit diaphragms were either displaced or absent. On day 7, the PHN rats were severely proteinuric, and most slit diaphragms were either absent, displaced, or replaced by occluding-type junctions. Immunofluorescence microscopy with antibodies to the external and cytoplasmic domains of nephrin showed a progressive loss of staining and a change in the distribution of nephrin from an interrupted linear pattern in normal controls to a more dispersed and clustered pattern in PHN. In contrast, the intensity of staining for ZO-1 and CD2-associated protein (CD2AP), two other proteins that are located on the cytoplasmic face of the slit diaphragm, was undiminished. Immunogold electron microscopy confirmed the progressive disappearance of nephrin from podocyte foot processes and retention of CD2AP. Glomeruli and glomerular cell membranes were extracted sequentially with Triton X-100, followed by DNase I or potassium iodide to depolymerize actin. Western blot analysis of the extracts showed a progressive decline of total nephrin on days 4 and 7 of PHN as well as a reduction in the actin-associated fraction. These findings show that nephrin partly dissociates from actin at the onset of podocyte injury in PHN. This is accompanied by a progressive loss of nephrin from the podocyte foot processes and prominent changes in the morphology of the slit diaphragms. These events may underlie the loss of podocyte barrier function in membranous nephropathy.
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Affiliation(s)
- Huaiping Yuan
- *Renal Section and Department of Medicine, Evans Biomedical Research Center, Boston University Medical Center, and Renal Unit and Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Emiko Takeuchi
- *Renal Section and Department of Medicine, Evans Biomedical Research Center, Boston University Medical Center, and Renal Unit and Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Gregory A Taylor
- *Renal Section and Department of Medicine, Evans Biomedical Research Center, Boston University Medical Center, and Renal Unit and Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Margaret McLaughlin
- *Renal Section and Department of Medicine, Evans Biomedical Research Center, Boston University Medical Center, and Renal Unit and Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Dennis Brown
- *Renal Section and Department of Medicine, Evans Biomedical Research Center, Boston University Medical Center, and Renal Unit and Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - David J Salant
- *Renal Section and Department of Medicine, Evans Biomedical Research Center, Boston University Medical Center, and Renal Unit and Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
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Wada T, Miyata T, Inagi R, Nangaku M, Wagatsuma M, Suzuki D, Wadzinski BE, Okubo K, Kurokawa K. Cloning and characterization of a novel subunit of protein serine/threonine phosphatase 4 from mesangial cells. J Am Soc Nephrol 2001; 12:2601-2608. [PMID: 11729228 DOI: 10.1681/asn.v12122601] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Mesangial cells play an important role in maintaining glomeruli structure and function and in the pathogenesis of glomerular diseases. With a novel approach using a rapid large-scale DNA sequencing strategy and computerized data processing, a new human gene, PP4(Rmeg) was cloned. The full-length cDNA clone of human PP4(Rmeg) coded for a novel 950-amino acid protein, which was similar to a subunit of protein serine/threonine phosphatase 4 (PP4). Recombinant PP4(Rmeg) produced in COS-7 cells bound to the catalytic subunit of PP4. PP4(Rmeg) is therefore structurally and functionally related to the recently reported regulatory subunit of PP4, PP4(R1). Amino acid sequence analysis of rat PP4(Rmeg) homologue revealed that the sequences were well conserved between human and rat (86.3% identity). Northern blot analyses of human tissues and cultured cells demonstrated that the regulatory subunits were expressed abundantly in human cultured mesangial cells, although their expression was relatively ubiquitous. In situ hybridization studies in normal human renal tissues confirmed their expression in glomeruli in vivo. The expression was upregulated in glomeruli of anti-Thy1 glomerulonephritis rats before mesangial proliferation. These data demonstrate that PP4(Rmeg) is a novel regulatory subunit of PP4, which is expressed ubiquitously but abundantly in mesangial cells. Its pathophysiologic role in mesangial cells and glomerulus remains unknown. As PP4 is an essential protein for nucleation, growth, and stabilization of microtubules at centrosomes/spindle pole bodies during cell division, PP4(Rmeg) may play a role in regulation of mitosis in mesangial cells.
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Affiliation(s)
- Takehiko Wada
- *Molecular and Cellular Nephrology, Institute of Medical Sciences and Department of Internal Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Department of Internal Medicine, University of Tokyo, Tokyo, and Institute for Molecular and Cellular Biology, Osaka University, Suita, Osaka, Japan; and Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Toshio Miyata
- *Molecular and Cellular Nephrology, Institute of Medical Sciences and Department of Internal Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Department of Internal Medicine, University of Tokyo, Tokyo, and Institute for Molecular and Cellular Biology, Osaka University, Suita, Osaka, Japan; and Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Reiko Inagi
- *Molecular and Cellular Nephrology, Institute of Medical Sciences and Department of Internal Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Department of Internal Medicine, University of Tokyo, Tokyo, and Institute for Molecular and Cellular Biology, Osaka University, Suita, Osaka, Japan; and Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Masaomi Nangaku
- *Molecular and Cellular Nephrology, Institute of Medical Sciences and Department of Internal Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Department of Internal Medicine, University of Tokyo, Tokyo, and Institute for Molecular and Cellular Biology, Osaka University, Suita, Osaka, Japan; and Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Masako Wagatsuma
- *Molecular and Cellular Nephrology, Institute of Medical Sciences and Department of Internal Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Department of Internal Medicine, University of Tokyo, Tokyo, and Institute for Molecular and Cellular Biology, Osaka University, Suita, Osaka, Japan; and Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Daisuke Suzuki
- *Molecular and Cellular Nephrology, Institute of Medical Sciences and Department of Internal Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Department of Internal Medicine, University of Tokyo, Tokyo, and Institute for Molecular and Cellular Biology, Osaka University, Suita, Osaka, Japan; and Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Brian E Wadzinski
- *Molecular and Cellular Nephrology, Institute of Medical Sciences and Department of Internal Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Department of Internal Medicine, University of Tokyo, Tokyo, and Institute for Molecular and Cellular Biology, Osaka University, Suita, Osaka, Japan; and Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Kousaku Okubo
- *Molecular and Cellular Nephrology, Institute of Medical Sciences and Department of Internal Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Department of Internal Medicine, University of Tokyo, Tokyo, and Institute for Molecular and Cellular Biology, Osaka University, Suita, Osaka, Japan; and Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Kiyoshi Kurokawa
- *Molecular and Cellular Nephrology, Institute of Medical Sciences and Department of Internal Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Department of Internal Medicine, University of Tokyo, Tokyo, and Institute for Molecular and Cellular Biology, Osaka University, Suita, Osaka, Japan; and Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
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Cunningham PN, Hack BK, Ren G, Minto AW, Morgan BP, Quigg RJ. Glomerular complement regulation is overwhelmed in passive Heymann nephritis. Kidney Int 2001; 60:900-9. [PMID: 11532085 DOI: 10.1046/j.1523-1755.2001.060003900.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND An injection of anti-Fx1A antibodies in rats leads to passive Heymann nephritis (PHN), a model of membranous nephropathy. Fx1A is a crude extract of renal cortex that contains megalin as a principal component. However, when rats are given anti-megalin antibodies, abnormal proteinuria does not occur. Because of the established complement dependence of PHN, we hypothesized that antibodies neutralizing complement regulatory proteins in the rat glomerulus also were required to induce PHN. Two likely targets are Crry and CD59, proteins abundant on the rat podocyte and contained within Fx1A that inhibit the C3 convertase and C5b-9 assembly, respectively. METHODS Rats were injected with anti-megalin monoclonal antibodies, followed by anti-Crry and/or anti-CD59 F(ab')(2) antibodies five days later. In a second group of experiments, rats were injected with anti-Fx1A or anti-Fx1A immunodepleted of reactivity against Crry and/or CD59. RESULTS In the setting of podocyte-associated anti-megalin monoclonal antibodies, simultaneous neutralization of Crry and CD59 function led to the development of significant proteinuria (11.0 +/- 2.1 mg/day, P < 0.001 vs. all other groups). In contrast, animals that had neither or only one of these complement regulators inhibited had normal urinary protein excretion (< or =6 mg/day). In animals given anti-Fx1A depleted of anti-Crry and/or anti-CD59, all groups developed typical PHN, characterized by heavy proteinuria and extensive glomerular deposition of C3 and C5b-9. CONCLUSION Crry and CD59 play an important role in restraining complement-mediated injury following subepithelial immune complex deposition; however, in PHN, their regulatory capacity is overwhelmed.
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Affiliation(s)
- P N Cunningham
- Section of Nephrology, The University of Chicago, Chicago, Illinois 60637, USA.
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Nangaku M, Miyata T, Suzuki D, Umezono T, Hashimoto T, Wada T, Yagi M, Nagano N, Inagi R, Kurokawa K. Cloning of rodent megsin revealed its up-regulation in mesangioproliferative nephritis. Kidney Int 2001; 60:641-52. [PMID: 11473647 DOI: 10.1046/j.1523-1755.2001.060002641.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND We recently cloned a new human mesangium-predominant gene, megsin. Megsin is a novel member of the serine protease inhibitor (serpin) superfamily. To elucidate functional roles of this gene, we cloned megsin in rodents and investigated its role in a rat nephritis model. METHODS Megsin homologues were cloned from cultured rat and mouse mesangial cDNAs utilizing polymerase chain reaction (PCR) with degenerative primers. Expression of megsin in three different types of resident glomerular cells was investigated by PCR. Levels of megsin mRNA expression at various time points in the anti-Thy1 rat nephritis model were studied by semiquantitative PCR and Northern blotting analysis. In order to investigate megsin protein expression in anti-Thy1 nephritis rats, we raised antibody against rat megsin-specific synthetic peptide, with which immunohistochemical studies were performed. RESULTS Rat and mouse megsins were composed of 380 amino acids, which revealed 75.3 and 73.9% identity, respectively, with human megsin at the amino acid level. Characteristic features as an inhibitory serpin were conserved in both rat and megsin megsins. PCR analysis revealed expression of megsin in cultured mesangial cells but not in glomerular epithelial or endothelial cells. In anti-Thy1 nephritis rats, semiquantitative PCR and Northern blotting showed that expression of megsin mRNA was up-regulated in glomeruli at day 8. Immunohistochemical studies demonstrated the prominent accumulation of megsin in glomeruli at the same time point. Megsin was mainly localized in mesangial area. The megsin expression level returned to the basal level at day 28. CONCLUSION Sequences of megsin were well conserved among different species. Rat megsin was also predominantly expressed in mesangial cells. Expression of megsin was up-regulated at the peak of hypercellularity and matrix accumulation in the mesangioproliferative glomerulonephritis model, suggesting that megsin may participate in the process of glomerulosclerosis by modulating extracellular matrix deposition or cell survival.
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Affiliation(s)
- M Nangaku
- Molecular and Cellular Nephrology, Institute of Medical Sciences Tokai University School of Medicine, Kanagawa, Japan.
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40
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Mostoslavsky G, Fischel R, Yachimovich N, Yarkoni Y, Rosenmann E, Monestier M, Baniyash M, Eilat D. Lupus anti-DNA autoantibodies cross-react with a glomerular structural protein: a case for tissue injury by molecular mimicry. Eur J Immunol 2001; 31:1221-7. [PMID: 11298348 DOI: 10.1002/1521-4141(200104)31:4<1221::aid-immu1221>3.0.co;2-p] [Citation(s) in RCA: 161] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Anti-DNA autoantibodies are the hallmark of human and murine systemic lupus erythematosus (SLE), an autoimmune rheumatic disease of unknown etiology. Some of these antibodies are believed to be pathogenic for kidney tissue and to initiate immune glomerulonephritis. However, the mechanisms by which anti-DNA antibodies participate in tissue injury remain controversial. We have studied the in vivo pathogenicity of anti-DNA monoclonal antibodies in immune deficient mice, using a panel of murine B cell hybridomas. No consistent genetic or immunochemical differences were found between pathogenic and non-pathogenic anti-DNA antibodies. However, the two antibody populations differed in their cross-reaction with the acidic actin-binding protein, alpha-actinin, that is known to play a major role in the structural integrity of glomerular filtration components. These results suggest that kidney dysfunction in SLE may be facilitated by protein-nucleic acid antigenic mimicry.
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MESH Headings
- Actinin/immunology
- Actinin/metabolism
- Animals
- Antibodies, Antinuclear/immunology
- Antibodies, Monoclonal/immunology
- B-Lymphocytes
- Cross Reactions/immunology
- Fluorescent Antibody Technique, Indirect
- Gene Deletion
- Genes, RAG-1/genetics
- Hybridomas
- Kidney Glomerulus/chemistry
- Kidney Glomerulus/immunology
- Kidney Glomerulus/metabolism
- Kidney Glomerulus/pathology
- Lupus Erythematosus, Systemic/immunology
- Lupus Erythematosus, Systemic/metabolism
- Lupus Erythematosus, Systemic/pathology
- Lupus Nephritis/immunology
- Lupus Nephritis/metabolism
- Lupus Nephritis/pathology
- Mice
- Mice, Knockout
- Microscopy, Electron
- Molecular Mimicry
- Rats
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
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Affiliation(s)
- G Mostoslavsky
- Department of Medicine, Hadassah University Hospital, Jerusalem, Israel
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41
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Mostoslavsky G, Fischel R, Yachimovich N, Yarkoni Y, Rosenmann E, Monestier M, Baniyash M, Eilat D. Lupus anti-DNA autoantibodies cross-react with a glomerular structural protein: a case for tissue injury by molecular mimicry. Eur J Immunol 2001. [DOI: 10.1002/1521-4141(200104)31:4%3c1221::aid-immu1221%3e3.0.co;2-p] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Blume C, Heise G, Mühlfeld A, Bach D, Schrör K, Gerhardz CD, Grabensee B, Heering P. Effect of flosulide, a selective cyclooxygenase 2 inhibitor, on passive heymann nephritis in the rat. Kidney Int 1999; 56:1770-8. [PMID: 10571785 DOI: 10.1046/j.1523-1755.1999.00742.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Nonsteroidal anti-inflammatory drugs (NSAIDs) induce an inhibition of cyclooxygenase (COX), an enzyme that makes prostaglandins. Two isoforms of COX exist: COX-1 represents the constitutively expressed enzyme, whereas COX-2 is the inducible isoform. This study investigated the role of COX-2 in the inflammatory processes of the kidneys of rats with passive Heymann nephritis (PHN), and focused of the effect of a selective COX-2 inhibitor, flosulide. COX-2-selective inhibitors are thought to represent potent anti-inflammatory agents without major renal side effects. METHODS PHN was induced by injecting heterologous Fx1A antiserum into female Wistar rats. Two treatment groups, each consisting of 12 rats with PHN, received either 3 or 9 mg of flosulide/kg body wt/day and were compared with untreated controls. After four weeks, the generation of thromboxane B2 (TxB2) and 6-keto-PGF1alpha were determined in renal tissue and in urine. COX-2 protein expression was investigated by Western blotting using a selective antibody. RESULTS Rats with PHN exhibited a marked proteinuria of 71 +/- 8 mg/24 hr as compared with 2.0 +/- 0.3 mg/24 hr in healthy controls (P < 0.01). Treatment with flosulide reduced the proteinuria to 26.1 +/- 9 mg/24 hr at 3 mg flosulide/kg body wt/day and 35.5 +/- 6 mg/24 hr at 9 mg/kg body wt/day, which was equivalent to a reduction of proteinuria by a maximum of 65% (P < 0.05). This was accompanied by an increase in glomerular TxB2 from 3073 +/- 355 to 5255 +/- 1041 pg/mg glomerular protein and 6-keto-PGF1alpha from 1702 +/- 161 to 2724 +/- 770 pg/mg glomerular protein in rats with PHN. COX-2 protein expression was also highly elevated in comparison to healthy controls. Low-dose flosulide treatment had no effect on COX protein expression and renal prostaglandin formation. High-dose flosulide treatment reduced renal prostaglandin production and caused a marked decline in COX-1 and COX-2 protein expression. Urine prostanoid excretion remained unchanged in all therapeutic groups. There was a small though significant reduction in renal creatinine clearance from 0.86 ml +/- 0.2/min in untreated controls to 0.6 ml +/- 0.1/min in flosulide-treated rats with PHN (P < 0.01) after four weeks. CONCLUSIONS Under the influence of flosulide, a highly COX-2-selective inhibitor, we observed an antiproteinuric drug effect. The inflammation in PHN induced COX-2 protein expression that was not affected by low-dose flosulide. COX-1 and COX-2 protein expression was affected by high-dose flosulide, which therefore might lose its selectivity. High-dose flosulide induced a decrease in glomerular prostanoid production possibly because of COX-1 inhibition. Our results suggest that the therapeutic use of flosulide in proteinuria seems advantageous and deserves further studies because the basal prostaglandin levels remain unchanged in the low-dose-treated group, indicating that the compensatory capacity of prostaglandin production, which is essential for the regulation of renal hemodynamics, is maintained.
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Affiliation(s)
- C Blume
- Klinik für Nephrologie und Rheumatologie, Institut für Pharmakologie,Universität Düsseldorf, Germany
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Abstract
Evidence is accumulating that directly responsible for the rate of progression of glomerular disease are specific positive (cyclins and cyclin-dependent kinases) and negative (cyclin-kinase inhibitors) cell cycle regulatory proteins. The challenge for nephrologists is to determine which ones are expressed in renal disease and their precise role in glomerular cell proliferation, hypertrophy and differentiation. Ultimately the goal is to find ever more appropriate therapeutic strategies to arrest or prevent progressive renal disease.
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Affiliation(s)
- S J Shankland
- Division of Nephrology, University of Washington, Seattle 98195, USA.
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Ostendorf T, Kunter U, Eitner F, Loos A, Regele H, Kerjaschki D, Henninger DD, Janjic N, Floege J. VEGF(165) mediates glomerular endothelial repair. J Clin Invest 1999; 104:913-23. [PMID: 10510332 PMCID: PMC408553 DOI: 10.1172/jci6740] [Citation(s) in RCA: 220] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
VEGF(165), the most abundant isoform in man, is an angiogenic cytokine that also regulates vascular permeability. Its function in the renal glomerulus, where it is expressed in visceral epithelial and mesangial cells, is unknown. To assess the role of VEGF(165) in glomerular disease, we administered a novel antagonist - a high-affinity, nuclease-resistant RNA aptamer coupled to 40-kDa polyethylene glycol (PEG) - to normal rats and to rats with mesangioproliferative nephritis, passive Heymann nephritis (PHN), or puromycin aminonucleoside nephrosis (PAN). In normal rats, antagonism of VEGF(165) for 21 days failed to induce glomerular pathology or proteinuria. In rats with mesangioproliferative nephritis, the VEGF(165) aptamer (but not a sequence-scrambled control RNA or PEG alone) led to a reduction of glomerular endothelial regeneration and an increase in endothelial cell death, provoking an 8-fold increase in the frequency of glomerular microaneurysms by day 6. In contrast, early leukocyte influx and the proliferation, activation, and matrix accumulation of mesangial cells were not affected in these rats. In rats with PHN or PAN, administration of the VEGF(165) aptamer did not influence the course of proteinuria using various dosages and administration routes. These data identify VEGF(165) as a factor of central importance for endothelial cell survival and repair in glomerular disease, and point to a potentially novel way to influence the course of glomerular diseases characterized by endothelial cell damage, such as various glomerulonephritides, thrombotic microangiopathies, or renal transplant rejection.
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Affiliation(s)
- T Ostendorf
- Division of Nephrology, Medizinische Hochschule, 30623 Hannover, Germany
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46
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Holzman LB, St John PL, Kovari IA, Verma R, Holthofer H, Abrahamson DR. Nephrin localizes to the slit pore of the glomerular epithelial cell. Kidney Int 1999; 56:1481-91. [PMID: 10504499 DOI: 10.1046/j.1523-1755.1999.00719.x] [Citation(s) in RCA: 237] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Recognition that mutation of the protein nephrin, encoded by the NPHS1 gene, singly results in the cellular alterations that result in foot process effacement, and nephrotic range proteinuria emphasizes the pivotal role that this protein plays in regulating glomerular filter integrity. This article reports the development of reagents necessary to study the biology of nephrin in mouse, and describes the initial characterization of the nephrin protein. METHODS A cDNA including the full-length mouse nephrin open reading frame was cloned and sequenced. Immuno-affinity purified polyclonal antiserum directed against the cytoplasmic domain of mouse nephrin was developed. RESULTS Nephrin identified in mouse glomerular extract was found to be a glycoprotein with an apparent molecular mass of 185 kDa. As detected by indirect immunofluorescence microscopy and immunogold electron microscopy, nephrin was located only in visceral glomerular epithelial cells, where it was targeted to intercellular junctions of mature podocyte foot processes. In developing glomeruli of newborn mouse, antinephrin immunolocalized to the earliest slit pore regions between differentiating podocytes, sites where slit diaphragms first become visible. CONCLUSION As a putative cell adhesion molecule of the immunoglobulin superfamily, nephrin likely participates in cell-cell interactions between podocyte foot processes and may represent a component of the slit diaphragm.
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Affiliation(s)
- L B Holzman
- University of Michigan Medical School, 1560 Medical Science Research Building II, Ann Arbor 48109-0676, USA.
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47
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Shankland SJ, Pippin JW, Couser WG. Complement (C5b-9) induces glomerular epithelial cell DNA synthesis but not proliferation in vitro. Kidney Int 1999; 56:538-48. [PMID: 10432393 DOI: 10.1046/j.1523-1755.1999.00560.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The C5b-9 membrane attack complex of complement is the principal mediator of injury induced experimentally by antibodies directed at glomerular cell membranes. In experimental membranous nephropathy, C5b-9 induced injury to the glomerular visceral epithelial cell (VEC) is associated with DNA synthesis, but not cytokinesis. In the current study we determined if C5b-9 increases DNA synthesis in VEC in vitro, and defined the mechanisms involved. METHODS Rat VEC in vitro were divided into three groups: (1) sensitized with anti-VEC antibody and exposed to sublytic concentrations of C +/PVG serum (normal complement components); (2) anti-VEC antibody and control C-/PVG serum (C6 deficient); (3) no anti-VEC antibody. DNA synthesis (BrdU staining), mitosis (mitotic figures) and cytokinesis (cell counts) were measured at 24 and 48 hours. To examine the expression of specific S-phase and M-phase cell cycle regulatory proteins and their inhibitors, immunostaining and Western blot analysis was performed for cyclin A, CDK2, p21 and p27, cyclin B and cdc2. RESULTS In the absence of growth factors, sublytic C5b-9 attack did not increase proliferation. In contrast, sublytic C5b-9 attack (group 1) augmented growth factor induced DNA synthesis by 50% compared to controls (groups 2 and 3; P < 0.001), and was accompanied by increased levels of cyclin A and CDK2, and a decrease in the cyclin kinase inhibitor p27 (but not p21). Sublytic C5b-9 attack reduced the expression of the M phase cell cycle proteins, cyclin B and cdc2, accompanied by reduced mitosis (mitotic figures) and cytokinesis (cell number). CONCLUSIONS Our results show that the C5b-9 augmented growth factor entry into the S phase in VEC is regulated by changes in specific cell cycle regulatory proteins. However, antibody and complement decreased the M phase cell cycle proteins, and prevented VEC mitosis and cytokinesis, suggesting a delay or arrest at the G2/M phase.
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Affiliation(s)
- S J Shankland
- Department of Medicine, University of Washington, Seattle 98195, USA.
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48
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Kim YG, Alpers CE, Brugarolas J, Johnson RJ, Couser WG, Shankland SJ. The cyclin kinase inhibitor p21CIP1/WAF1 limits glomerular epithelial cell proliferation in experimental glomerulonephritis. Kidney Int 1999; 55:2349-61. [PMID: 10354282 DOI: 10.1046/j.1523-1755.1999.00504.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND During glomerulogenesis, visceral glomerular epithelial cells (VECs) exit the cell cycle and become terminally differentiated and quiescent. In contrast to other resident glomerular cells, VECs undergo little if any proliferation in response to injury. However, the mechanisms for this remain unclear. Cell proliferation is controlled by cell-cycle regulatory proteins where the cyclin-dependent kinase inhibitor p21Cip1,WAF1 (p21) inhibits cell proliferation and is required for differentiation of many nonrenal cell types. METHODS To test the hypothesis that p21 is required to maintain a differentiated and quiescent VEC phenotype, experimental glomerulonephritis was induced in p21 knockout (-/-) and p21 wild-type (+/+) mice with antiglomerular antibody. DNA synthesis (proliferating cell nuclear antigen, bromodeoxyuridine staining), VEC proliferation (multilayers of cells in Bowman's space), matrix accumulation (periodic acid-Schiff, silver staining), apoptosis (TUNEL), and renal function (serum urea nitrogen) were studied on days 5 and 14 (N = 6 per time point). VECs were identified by location, morphology, ezrin staining, and electron microscopy. VEC differentiation was measured by staining for Wilms' tumor-1 gene. RESULTS Kidneys from unmanipulated p21-/- mice were histologically normal and did not have increased DNA synthesis, suggesting that p21 was not required for the induction of VEC terminal differentiation. Proliferating cell nuclear antigen and bromodeoxyuridine staining was increased 4.3- and 3.3-fold, respectively, in p21-/- mice with glomerulonephritis (P < 0.0001 vs. p21+/+ mice). At each time point, VEC proliferation was also increased in nephritic p21-/- mice (P < 0.0001 vs. p21+/+ mice). VEC re-entry into the cell cycle was associated with the loss of Wilms' tumor-1 gene staining. Nephritic p21-/- mice had increased extracellular matrix protein accumulation and apoptosis and decreased renal function (serum urea nitrogen) compared with p21+/+ mice (P < 0.001). CONCLUSION These results show that the cyclin kinase inhibitor p21 is not required by VECs to attain a terminally differentiated VEC phenotype. However, the loss of p21, in disease states, is associated with VEC re-entry into the cell cycle and the development of a dedifferentiated proliferative phenotype.
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Affiliation(s)
- Y G Kim
- Department of Medicine, University of Washington School of Medicine, Seattle, Washington, USA
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49
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Ophascharoensuk V, Fero ML, Hughes J, Roberts JM, Shankland SJ. The cyclin-dependent kinase inhibitor p27Kip1 safeguards against inflammatory injury. Nat Med 1998; 4:575-80. [PMID: 9585231 DOI: 10.1038/nm0598-575] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The cyclin-dependent kinase inhibitor p27Kip1 controls cell proliferation in response to normal mitogenic stimuli. We show here that p27Kip1 also safeguards against excessive cell proliferation in specific pathophysiologic settings. We used experimental glomerulonephritis as a paradigm for immune mediated inflammation and ureteral obstruction as a model for non-immune mediated inflammation. Renal function was substantially decreased in nephritic p27-/- mice compared with control mice, and this was associated with increased glomerular cell proliferation, apoptosis and matrix protein accumulation. Tubular epithelial cell proliferation and apoptosis was also increased in p27-/- mice following ureteral obstruction. p27Kip1 may have a general role in protecting cells and tissues from inflammatory injury.
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Affiliation(s)
- V Ophascharoensuk
- Department of Medicine, University of Washington School of Medicine, Seattle 98195-6521, USA
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50
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Valentin JP, Ying WZ, Couser WG, Humphreys MH. Extrarenal resistance to atrial natriuretic peptide in rats with experimental nephrotic syndrome. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:F556-63. [PMID: 9530272 DOI: 10.1152/ajprenal.1998.274.3.f556] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nephrotic syndrome is associated with resistance to the renal actions of atrial natriuretic peptide (ANP). We performed experiments in anesthetized, acutely nephrectomized rats 21-28 days after injection of adriamycin (7-8 mg/kg i.v.) or 9-14 days after injection of anti-Fx1A antiserum (5 ml/kg i.p.) (passive Heymann nephritis; PHN) to test whether extrarenal resistance also occurred. Proteinuria was significantly elevated in both models compared with controls before study. ANP infusion (1 microgram.kg-1.min-1) caused arterial pressure to decrease similarly in control rats, adriamycin-treated rats, and rats with PHN (by 8.2 +/- 1.0, 9.4 +/- 2.3, and 9.0 +/- 2.0%, respectively; all P < 0.05 vs. both baseline and vehicle-infused control rats). In control rats, hematocrit increased progressively to a maximal value 9.5 +/- 0.9% over baseline as a result of the infusion, an increase corresponding to a reduction in plasma volume of 16.1 +/- 0.9%. The ANP-induced increase in hematocrit was preserved in adriamycin-treated rats (9.2 +/- 1.3%) but was markedly blunted in rats with PHN (2.4 +/- 1.3%; P < 0.0001 vs. ANP infusion in control rats). ANP infusion increased plasma ANP levels to the same extent in the three groups, whereas plasma guanosine 3',5'-cyclic monophosphate was significantly lower in rats with PHN compared with both control and adriamycin-treated rats. Infusion of a subpressor dose of angiotensin II (ANG II, 2.5 ng.kg-1.min-1) fully restored the ANP-induced increase in hematocrit in rats with PHN. This study demonstrates that 1) the hemoconcentrating and hypotensive actions of ANP are preserved in adriamycin-treated rats, 2) the effect of ANP on hematocrit and fluid distribution is blunted in rats with PHN while its hypotensive action is preserved, and 3) low-level ANG II infusion normalizes the hemoconcentrating effect of exogenously infused ANP in rats with PHN. Thus deficient ANG II generation in rats with PHN, but not adriamycin nephrosis, may contribute to extrarenal ANP resistance.
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Affiliation(s)
- J P Valentin
- Division of Nephrology, San Francisco General Hospital, University of California San Francisco 94143, USA
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