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Guo B, Lyu Q, Slivano OJ, Dirkx R, Christie CK, Czyzyk J, Hezel AF, Gharavi AG, Small EM, Miano JM. Serum Response Factor Is Essential for Maintenance of Podocyte Structure and Function. J Am Soc Nephrol 2017; 29:416-422. [PMID: 29114040 DOI: 10.1681/asn.2017050473] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 10/11/2017] [Indexed: 01/15/2023] Open
Abstract
Podocytes contain an intricate actin cytoskeleton that is essential for the specialized function of this cell type in renal filtration. Serum response factor (SRF) is a master transcription factor for the actin cytoskeleton, but the in vivo expression and function of SRF in podocytes are unknown. We found that SRF protein colocalizes with podocyte markers in human and mouse kidneys. Compared with littermate controls, mice in which the Srf gene was conditionally inactivated with NPHS2-Cre exhibited early postnatal proteinuria, hypoalbuminemia, and azotemia. Histologic changes in the mutant mice included glomerular capillary dilation and mild glomerulosclerosis, with reduced expression of multiple canonical podocyte markers. We also noted tubular dilation, cell proliferation, and protein casts as well as reactive changes in mesangial cells and interstitial inflammation. Ultrastructure analysis disclosed foot process effacement with loss of slit diaphragms. To ascertain the importance of SRF cofactors in podocyte function, we disabled the myocardin-related transcription factor A and B genes. Although loss of either SRF cofactor alone had no observable effect in the kidney, deficiency of both recapitulated the Srf-null phenotype. These results establish a vital role for SRF and two SRF cofactors in the maintenance of podocyte structure and function.
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Affiliation(s)
- Bing Guo
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York.,Department of Hepatobiliary Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qing Lyu
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Orazio J Slivano
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Ronald Dirkx
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Christine K Christie
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Jan Czyzyk
- Department of Pathology and Laboratory Medicine and
| | - Aram F Hezel
- James P. Wilmot Cancer Center, University of Rochester School of Medicine and Dentistry, Rochester, New York; and
| | - Ali G Gharavi
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, New York
| | - Eric M Small
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Joseph M Miano
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York;
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Abstract
Lysophosphatidic acid (LPA) is a bioactive phospholipid that can exert diverse biological effects in various diseased states of the kidney by activating at least six cognate G protein-coupled receptors and its complex network of heterotrimeric G proteins. In many models of acute and chronic kidney injury, pathological elevations in LPA promotes abnormal changes in renal tubular epithelial cell architecture by activating apoptotic signaling, recruits immune cells to the site of injury, and stimulates profibrotic signaling by increasing gene transcription. In renal cancers, LPA can promote vascular cell proliferation and tumor cell invasion. In this review, a summary will be provided to describe the involvement of LPA, its synthetic enzymes, and its associated receptors in normal and diseased kidneys. Further elucidation of the LPA system may open new doors in developing a lipid-receptor therapeutic platform for kidney diseases.
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Affiliation(s)
- Frank Park
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Duane D Miller
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee
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53
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Sakai N, Nakamura M, Lipson KE, Miyake T, Kamikawa Y, Sagara A, Shinozaki Y, Kitajima S, Toyama T, Hara A, Iwata Y, Shimizu M, Furuichi K, Kaneko S, Tager AM, Wada T. Inhibition of CTGF ameliorates peritoneal fibrosis through suppression of fibroblast and myofibroblast accumulation and angiogenesis. Sci Rep 2017; 7:5392. [PMID: 28710437 PMCID: PMC5511333 DOI: 10.1038/s41598-017-05624-2] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 05/31/2017] [Indexed: 01/06/2023] Open
Abstract
Peritoneal fibrosis (PF) is a serious complication in various clinical settings, but the mechanisms driving it remain to be fully determined. Connective tissue growth factor (CTGF) is known to regulate fibroblast activities. We therefore examined if CTGF inhibition has anti-fibrotic effects in PF. PF was induced by repetitive intraperitoneal injections of chlorhexidine gluconate (CG) in mice with type I pro-collagen promoter-driven green fluorescent protein (GFP) expression to identify fibroblasts. FG-3019, an anti-CTGF monoclonal antibody, was used to inhibit CTGF. CG-induced PF was significantly attenuated in FG-3019-treated mice. CG challenges induced marked accumulations of proliferating fibroblasts and of myofibroblasts, which were both reduced by FG-3019. Levels of peritoneal CTGF expression were increased by CG challenges, and suppressed in FG-3019-treated mice. FG-3019 treatment also reduced the number of CD31+ vessels and VEGF-A-positive cells in fibrotic peritoneum. In vitro studies using NIH 3T3 fibroblasts and peritoneal mesothelial cells (PMCs) showed that CTGF blockade suppressed TGF-β1-induced fibroblast proliferation and myofibroblast differentiation, PMC mesothelial-to-mesenchymal transition, and VEGF-A production. These findings suggest that the inhibition of CTGF by FG-3019 might be a novel treatment for PF through the regulation of fibroblast and myofibroblast accumulation and angiogenesis.
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Affiliation(s)
- Norihiko Sakai
- Division of Nephrology, Kanazawa University Hospital, Kanazawa, 920-8641, Japan. .,Division of Blood Purification, Kanazawa University Hospital, Kanazawa, 920-8641, Japan.
| | - Miki Nakamura
- Department of Nephrology and Laboratory Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-8641, Japan
| | | | - Taito Miyake
- Division of Nephrology, Kanazawa University Hospital, Kanazawa, 920-8641, Japan
| | - Yasutaka Kamikawa
- Division of Nephrology, Kanazawa University Hospital, Kanazawa, 920-8641, Japan
| | - Akihiro Sagara
- Division of Nephrology, Kanazawa University Hospital, Kanazawa, 920-8641, Japan
| | - Yasuyuki Shinozaki
- Division of Nephrology, Kanazawa University Hospital, Kanazawa, 920-8641, Japan
| | - Shinji Kitajima
- Division of Nephrology, Kanazawa University Hospital, Kanazawa, 920-8641, Japan
| | - Tadashi Toyama
- Division of Nephrology, Kanazawa University Hospital, Kanazawa, 920-8641, Japan
| | - Akinori Hara
- Division of Nephrology, Kanazawa University Hospital, Kanazawa, 920-8641, Japan
| | - Yasunori Iwata
- Division of Nephrology, Kanazawa University Hospital, Kanazawa, 920-8641, Japan
| | - Miho Shimizu
- Division of Nephrology, Kanazawa University Hospital, Kanazawa, 920-8641, Japan
| | - Kengo Furuichi
- Division of Nephrology, Kanazawa University Hospital, Kanazawa, 920-8641, Japan.,Division of Blood Purification, Kanazawa University Hospital, Kanazawa, 920-8641, Japan
| | - Shuichi Kaneko
- Department of System Biology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-8641, Japan
| | - Andrew M Tager
- Center for Immunology and Inflammatory Diseases, Harvard Medical School, Boston, MA, 02114, USA.,Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Takashi Wada
- Division of Nephrology, Kanazawa University Hospital, Kanazawa, 920-8641, Japan.,Department of Nephrology and Laboratory Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-8641, Japan
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