151
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Umeukeje EM, Young BA. Genetics and ESKD Disparities in African Americans. Am J Kidney Dis 2019; 74:811-821. [PMID: 31606237 PMCID: PMC7373097 DOI: 10.1053/j.ajkd.2019.06.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 06/09/2019] [Indexed: 12/22/2022]
Abstract
African Americans have a 2- to 4-fold greater incidence of end-stage kidney disease (ESKD) than whites, which has long raised the possibility of a genetic cause for this disparity. Recent advances in genetic studies have shown a causal association of polymorphisms at the apolipoprotein L1 gene (APOL1) with the markedly increased risk for the nondiabetic component of the overall disparity in ESKD in African Americans. Although APOL1-associated kidney disease is thought to account for a substantial proportion of ESKD in African Americans, not all the increased risk for ESKD is accounted for, and a complete cataloging of disparities in genetic causes of ESKD eludes our current understanding of genetic-associated kidney disease. Genetic testing aids the screening, diagnosis, prognosis, and treatment of diseases with a genetic basis. Widespread use of genetic testing in clinical practice is limited by the small number of actionable genetic variants, limited health literacy of providers and patients, and underlying complex ethical, legal, and social issues. This perspective reviews racial and ethnic differences associated with genetic diseases and the development of ESKD in African Americans and discusses potential uncertainties associated with our current understanding of penetrance of genetically linked kidney disease and population-attributable risk percent.
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Affiliation(s)
- Ebele M Umeukeje
- Division of Nephrology, Vanderbilt University Medical Center, Nashville, TN; Vanderbilt Center for Kidney Disease, Nashville, TN
| | - Bessie A Young
- Nephrology, Hospital and Specialty Medicine and Center for Innovation for Veteran-Centered and Value Driven Care, Veterans Affairs Puget Sound Health Care System, Seattle, WA; Kidney Research Institute and Division of Nephrology, University of Washington, Seattle, WA.
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152
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Kampf LL, Schneider R, Gerstner L, Thünauer R, Chen M, Helmstädter M, Amar A, Onuchic-Whitford AC, Loza Munarriz R, Berdeli A, Müller D, Schrezenmeier E, Budde K, Mane S, Laricchia KM, Rehm HL, MacArthur DG, Lifton RP, Walz G, Römer W, Bergmann C, Hildebrandt F, Hermle T. TBC1D8B Mutations Implicate RAB11-Dependent Vesicular Trafficking in the Pathogenesis of Nephrotic Syndrome. J Am Soc Nephrol 2019; 30:2338-2353. [PMID: 31732614 DOI: 10.1681/asn.2019040414] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/07/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Mutations in about 50 genes have been identified as monogenic causes of nephrotic syndrome, a frequent cause of CKD. These genes delineated the pathogenetic pathways and rendered significant insight into podocyte biology. METHODS We used whole-exome sequencing to identify novel monogenic causes of steroid-resistant nephrotic syndrome (SRNS). We analyzed the functional significance of an SRNS-associated gene in vitro and in podocyte-like Drosophila nephrocytes. RESULTS We identified hemizygous missense mutations in the gene TBC1D8B in five families with nephrotic syndrome. Coimmunoprecipitation assays indicated interactions between TBC1D8B and active forms of RAB11. Silencing TBC1D8B in HEK293T cells increased basal autophagy and exocytosis, two cellular functions that are independently regulated by RAB11. This suggests that TBC1D8B plays a regulatory role by inhibiting endogenous RAB11. Coimmunoprecipitation assays showed TBC1D8B also interacts with the slit diaphragm protein nephrin, and colocalizes with it in immortalized cell lines. Overexpressed murine Tbc1d8b with patient-derived mutations had lower affinity for endogenous RAB11 and nephrin compared with wild-type Tbc1d8b protein. Knockdown of Tbc1d8b in Drosophila impaired function of the podocyte-like nephrocytes, and caused mistrafficking of Sns, the Drosophila ortholog of nephrin. Expression of Rab11 RNAi in nephrocytes entailed defective delivery of slit diaphragm protein to the membrane, whereas RAB11 overexpression revealed a partial phenotypic overlap to Tbc1d8b loss of function. CONCLUSIONS Novel mutations in TBC1D8B are monogenic causes of SRNS. This gene inhibits RAB11. Our findings suggest that RAB11-dependent vesicular nephrin trafficking plays a role in the pathogenesis of nephrotic syndrome.
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Affiliation(s)
- Lina L Kampf
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Ronen Schneider
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Lea Gerstner
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Roland Thünauer
- Signalling Research Centres BIOSS and CIBSS and Faculty of Biology, University of Freiburg, Freiburg, Germany.,Advanced Light and Fluorescence Microscopy Facility, Centre for Structural Systems Biology (CSSB) and University of Hamburg, Hamburg, Germany
| | - Mengmeng Chen
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Martin Helmstädter
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Ali Amar
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Ana C Onuchic-Whitford
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts.,Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | | | - Afig Berdeli
- Department of Pediatrics, Molecular Medicine Laboratory, Ege University, Izmir, Turkey
| | - Dominik Müller
- Department of Pediatric Nephrology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Eva Schrezenmeier
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Klemens Budde
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Shrikant Mane
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut
| | - Kristen M Laricchia
- Broad Center for Mendelian Genomics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge
| | - Heidi L Rehm
- Broad Center for Mendelian Genomics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge
| | - Daniel G MacArthur
- Broad Center for Mendelian Genomics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge
| | - Richard P Lifton
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut.,Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, New York
| | - Gerd Walz
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Winfried Römer
- Signalling Research Centres BIOSS and CIBSS and Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Carsten Bergmann
- Center for Human Genetics, Mainz, Germany.,Center for Human Genetics, Bioscientia, Ingelheim, Germany; and.,Department of Medicine, University Hospital Freiburg, Freiburg, Germany
| | - Friedhelm Hildebrandt
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts;
| | - Tobias Hermle
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany;
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153
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Kim S, Kalappurakkal JM, Mayor S, Rosen MK. Phosphorylation of nephrin induces phase separated domains that move through actomyosin contraction. Mol Biol Cell 2019; 30:2996-3012. [PMID: 31599693 PMCID: PMC6857567 DOI: 10.1091/mbc.e18-12-0823] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 09/03/2019] [Accepted: 10/03/2019] [Indexed: 01/12/2023] Open
Abstract
The plasma membrane of eukaryotic cells is organized into lipid and protein microdomains, whose assembly mechanisms and functions are incompletely understood. We demonstrate that proteins in the nephrin/Nck/N-WASP actin-regulatory pathway cluster into micron-scale domains at the basal plasma membrane upon triggered phosphorylation of transmembrane protein nephrin. The domains are persistent but readily exchange components with their surroundings, and their formation is dependent on the number of Nck SH3 domains, suggesting they are phase separated polymers assembled through multivalent interactions among the three proteins. The domains form independent of the actin cytoskeleton, but acto-myosin contractility induces their rapid lateral movement. Nephrin phosphorylation induces larger clusters at the cell periphery, which are associated with extensive actin assembly and dense filopodia. Our studies illustrate how multivalent interactions between proteins at the plasma membrane can produce micron-scale organization of signaling molecules, and how the resulting clusters can both respond to and control the actin cytoskeleton.
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Affiliation(s)
- Soyeon Kim
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
- The HHMI/MBL Summer Institute, Marine Biological Laboratory, Woods Hole, MA 02543
| | - Joseph M. Kalappurakkal
- The HHMI/MBL Summer Institute, Marine Biological Laboratory, Woods Hole, MA 02543
- National Centre for Biological Sciences, Bangalore 560065, India
| | - Satyajit Mayor
- The HHMI/MBL Summer Institute, Marine Biological Laboratory, Woods Hole, MA 02543
- National Centre for Biological Sciences, Bangalore 560065, India
| | - Michael K. Rosen
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
- The HHMI/MBL Summer Institute, Marine Biological Laboratory, Woods Hole, MA 02543
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154
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Molecular stratification of idiopathic nephrotic syndrome. Nat Rev Nephrol 2019; 15:750-765. [DOI: 10.1038/s41581-019-0217-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2019] [Indexed: 01/03/2023]
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155
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Wakashin H, Seo E, Seo Y. Size-selective filtration of the atrial wall estimated from the accumulation of tracers in the kidney of the mussel Mytilus galloprovincialis. ACTA ACUST UNITED AC 2019; 222:jeb.209171. [PMID: 31548287 DOI: 10.1242/jeb.209171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 09/17/2019] [Indexed: 11/20/2022]
Abstract
In order to determine the molecular weight cut-off (MWCO) for the atrial wall filtration into kidneys of the Mytilus galloprovincialis, we employed five magnetic resonance (MR) tracers: manganese chloride (Mn2+), gadolinium chloride (Gd3+), manganese-ethylenediaminetetraacetic acid (MnEDTA), gadolinium-diethylenetriamine pentaacetic acid (GdDTPA) and oligomer-based contrast agent (CH3-DTPA-Gd). After injection of the MR tracers (1 or 2 mmol l-1×0.1 ml) into the visceral mass, T 1-weighted MR imaging (T 1w-MRI) and the longitudinal relaxation rates (1/T 1=R 1) were measured at 20°C. The MR tracers were distributed uniformly in the visceral mass within 1 h after injection. The T 1w-MRI intensity and R 1 of the kidney (R 1K) were increased by Mn2+ and MnEDTA, with urine concentrations estimated at 210 and 65 µmol l-1, respectively. The rest of the tracers showed only minimal or no increase. When the mussels were additionally incubated in seawater with 10 µmol l-1 MnCl2, R 1K was increased in the GdDTPA group, but not in the GdCl3 group. Therefore, Gd3+ might have inhibited renal accumulation of Mn2+ and Gd3+ Incubation in seawater with 10 µmol l-1 MnEDTA showed no increase in the R 1K, but additional incubation with 10 µmol l-1 MnCl2 caused an increase in R 1K It is suggested that injected MnEDTA was filtrated as MnEDTA per se, and not likely separated into free Mn2+ Thus, we concluded that the MWCO of the atrial wall of the M. galloprovincialis is around 0.5 kDa, which is almost 1/100 of that for vertebrate animals, and suggests a reduction in efforts to reabsorb metabolites and osmolytes from the urine.
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Affiliation(s)
- Hidefumi Wakashin
- Department of Regulatory Physiology, Dokkyo Medical University School of Medicine, Tochigi 321-0293, Japan
| | - Eriko Seo
- Department of Marine Ecosystem Dynamics, Division of Marine Life Science, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa 277-8564, Japan
| | - Yoshiteru Seo
- Department of Regulatory Physiology, Dokkyo Medical University School of Medicine, Tochigi 321-0293, Japan
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156
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Wang J, Fu D, Senouthai S, You Y. Critical roles of PI3K/Akt/NF‑κB survival axis in angiotensin II‑induced podocyte injury. Mol Med Rep 2019; 20:5134-5144. [PMID: 31638199 PMCID: PMC6854545 DOI: 10.3892/mmr.2019.10733] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 08/30/2019] [Indexed: 12/12/2022] Open
Abstract
Numerous studies have reported that angiotensin (Ang) II, nephrin, and podocin serve pivotal roles in podocyte injury, and thus can lead to the occurrence of proteinuria and the progression of kidney diseases. This study aimed to investigate the effects of Ang II on the production of nephrin and podocin, and their relationship with podocyte injury. We also aimed to determine whether nephrin, podocin and caspase-9 production depends on the PI3K/Akt/nuclear factor (NF)-κB signaling pathway in cultured mouse podocytes. We treated mouse podocytes with different doses of Ang II (10−9, 10−8, 10−7 and 10−6 mol/l) for 12, 24, and 48 h to analyse cell viability, and at 10−6 mol/l Ang II for 12, 24, and 48 h to evaluate cell apoptosis. Cells were treated with 10−6 mol/l of Ang II and/or LY294002 (inhibitor of Akt) or 740Y-P (activator of PI3K) for 48 h to detect Akt, phosphorylated (phospho)-Akt, p65 NF-κB, and phospho-p65 NF-κB, nephrin, podocin and caspase-9 expression, and podocyte apoptosis. Treatment with Ang II suppressed the viability and promoted the apoptosis of podocytes in a dose- and time-dependent manner. Ang II decreased phospho-Akt, phospho-p65 NF-κB, nephrin, and podocin and increased caspase-9 expression, while podocyte apoptosis was promoted. LY294002 further enhanced Ang II-induced downregulation of Akt and p65 NF-κB activation, as well as upregulation of caspase-9 mRNA and protein, and promoted the apoptosis of podocytes. Of note, 740Y-P restored Ang II-induced downregulation of Akt and p65 NF-κB activation, and upregulation of caspase-9, and decreased podocyte apoptosis. Interestingly, LY294002 and 740Y-P were determined to have no notable effects on the expression of nephrin and podocin. The data suggested that Ang II could regulate the expression of nephrin, podocin and caspase-9. Collectively, our findings suggested that the PI3K/Akt/NF-κB survival axis may serve a pivotal role in podocyte injury.
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Affiliation(s)
- Junjie Wang
- Department of Nephrology, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, Guangxi Zhuang Autonomous Region 533000, P.R. China
| | - Dongdong Fu
- Department of Nephrology, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, Guangxi Zhuang Autonomous Region 533000, P.R. China
| | - Soulixay Senouthai
- Department of Nephrology, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, Guangxi Zhuang Autonomous Region 533000, P.R. China
| | - Yanwu You
- Department of Nephrology, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, Guangxi Zhuang Autonomous Region 533000, P.R. China
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157
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Wang H, Sheng J, He H, Chen X, Li J, Tan R, Wang L, Lan HY. A simple and highly purified method for isolation of glomeruli from the mouse kidney. Am J Physiol Renal Physiol 2019; 317:F1217-F1223. [PMID: 31566437 DOI: 10.1152/ajprenal.00293.2019] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Highly purified mouse glomeruli are of great value for studying glomerulus-associated kidney diseases. Here, we developed a simple and rapid procedure for mouse glomerular isolation with large quantity and high purity based on the combination of size-selective sieving and differential adhesion techniques, which we termed the "differential adhesion method." In this method, mouse renal cortices were minced and digested with collagenase. Glomeruli were disassociated from tubules by successive sieving through 105-, 75-, and 40-μm cell strainers. The retained glomeruli-rich preparation on the 40-μm strainer was rinsed into a cell culture dish to allow tubules to adhere quickly to the dish while leaving most glomeruli floating (termed "differential adhesion"). The floating glomerular fraction was then subjected to another wash through the 40-μm strainer followed by an additional differential adhesion step to obtain highly purified glomeruli with yields of 8,357 ± 575 and purity of 96.1 ± 1.8% from one adult C57BL/6 mouse. The purity of the isolated glomeruli was further confirmed by high expression of the podocyte marker nephrin without detectable tubular marker cadherin-16. Importantly, we also found that although both the quantity and purity of the isolated glomeruli by this and the established Dynabeads method were comparable, glomeruli isolated by the current method showed much less inflammatory stress in terms of proinflammatory cytokine expression than the Dynabeads method. In conclusion, we established a newly mouse glomerular isolation method that is simple, rapid, cost effective, and productive. It provides an advanced methodology for research into glomerulus-related kidney diseases in the mouse.
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Affiliation(s)
- Honglian Wang
- Research Center for Integrated Medicine, Affiliated Traditional Medicine Hospital of Southwest Medical University, Luzhou, Sichuan, China.,Department of Medicine and Therapeutics and Li Ka Shing Institute of Health Sciences, the Chinese University of Hong Kong, Hong Kong, China
| | - Jingyi Sheng
- Department of Medicine and Therapeutics and Li Ka Shing Institute of Health Sciences, the Chinese University of Hong Kong, Hong Kong, China
| | - Huijun He
- Department of Medicine and Therapeutics and Li Ka Shing Institute of Health Sciences, the Chinese University of Hong Kong, Hong Kong, China
| | - Xiaocui Chen
- Department of Medicine and Therapeutics and Li Ka Shing Institute of Health Sciences, the Chinese University of Hong Kong, Hong Kong, China
| | - Jinhong Li
- Department of Nephrology, the Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Ruizhi Tan
- Research Center for Integrated Medicine, Affiliated Traditional Medicine Hospital of Southwest Medical University, Luzhou, Sichuan, China
| | - Li Wang
- Research Center for Integrated Medicine, Affiliated Traditional Medicine Hospital of Southwest Medical University, Luzhou, Sichuan, China
| | - Hui-Yao Lan
- Department of Medicine and Therapeutics and Li Ka Shing Institute of Health Sciences, the Chinese University of Hong Kong, Hong Kong, China
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158
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Tsai IJ, Lin WC, Yang YH, Tseng YL, Lin YH, Chou CH, Tsau YK. High Concentration of C5a-Induced Mitochondria-Dependent Apoptosis in Murine Kidney Endothelial Cells. Int J Mol Sci 2019; 20:ijms20184465. [PMID: 31510052 PMCID: PMC6770645 DOI: 10.3390/ijms20184465] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 09/02/2019] [Accepted: 09/09/2019] [Indexed: 12/22/2022] Open
Abstract
Patients with a relapse of idiopathic nephrotic syndrome have significantly increased levels of serum complement component 5a (C5a), and proteinuria has been noted in mice treated with C5a via changes in permeability of kidney endothelial cells (KECs) in established animal models. However, the apoptosis of KECs treated with high concentrations of C5a has also been observed. As mitochondrial damage is known to be important in cell apoptosis, the aim of this study was to examine the association between C5a-induced mouse KEC apoptosis and mitochondrial damage. Mouse KECs were isolated and treated with different concentrations of C5a. Cell viability assays showed that a high-concentration mouse recombinant protein C5a (rmC5a) treatment reduced mouse KEC growth. Cell cycle phase analysis, including apoptosis (sub-G1 phase) showed an increased percentage of the subG1 phase with a high-concentration rmC5a treatment. Cytochrome c and caspase 3/9 activities were significantly induced in the mouse KECs after a high-dose rmC5a (50 ng/mL) treatment, and this was rescued by pretreatment with the C5a receptor (C5aR) inhibitor (W-54011) and N-acetylcysteine (NAC). Reactive oxygen species (ROS) formation was detected in C5a-treated mouse KECs; however, W-54011 or NAC pretreatment inhibited high-dose rmC5a-induced ROS formation and also reduced cytochrome c release, apoptotic cell formation, and apoptotic DNA fragmentation. These factors determined the apoptosis of mouse KECs treated with high-dose C5a through C5aR and subsequently led to apoptosis via ROS regeneration and cytochrome c release. The results showed that high concentrations of C5a induced mouse KEC apoptosis via a C5aR/ROS/mitochondria-dependent pathway. These findings may shed light on the potential mechanism of glomerular sclerosis, a process in idiopathic nephrotic syndrome causing renal function impairment.
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Affiliation(s)
- I-Jung Tsai
- Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei 100, Taiwan.
| | - Wei-Chou Lin
- Department of Pathology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei 100, Taiwan.
| | - Yao-Hsu Yang
- Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei 100, Taiwan.
| | - Yu-Lin Tseng
- Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei 100, Taiwan.
| | - Yen-Hung Lin
- Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei 100, Taiwan.
| | - Chia-Hung Chou
- Department of Obstetrics and Gynecology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei 100, Taiwan.
| | - Yong-Kwei Tsau
- Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei 100, Taiwan.
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159
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Wang Y, Zhao S, Gu Y, Lewis DF. Loss of slit protein nephrin is associated with reduced antioxidant superoxide dismutase expression in podocytes shed from women with preeclampsia. Physiol Rep 2019; 6:e13785. [PMID: 29981208 PMCID: PMC6035334 DOI: 10.14814/phy2.13785] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 06/13/2018] [Indexed: 01/19/2023] Open
Abstract
Recent findings of podocyte shedding/podocyturia highlight the central significance of podocyte injury in preeclampsia, a hypertensive disorder unique to human pregnancy. To test the hypothesis that oxidative stress contributes to kidney podocyte injury in preeclampsia, we specifically examined expression and distribution of antioxidant CuZn‐SOD with nephrin and podoplanin in shed podocytes from women with preeclampsia. Human podocyte AB 8/13 cells served as control. We found that CuZn‐SOD was localized at the front/outreach region of nephrin at the cell periphery (foot process areas) in control podocytes and expression of CuZn‐SOD, nephrin, and podoplanin were all dislocated or lost in shed podocytes from preeclamptic patients. We further tested oxidative stress‐induced nephrin shedding in podocytes, in which AB 8/13 podocytes were cultured under lowered oxygen condition (2%O2) or treated with hypoxic mimicking agent cobalt chloride. Our results showed that reduced nephrin and podoplanin expression were associated with downregulation of CuZn‐SOD expression in podocytes when cells were cultured under lowered oxygen or hypoxic conditions. Nephrin shed in urinary specimen from preeclamptic women was also determined by immunoprecipitation/immunoblotting. The molecular sizes of nephrin that corresponded to that were lost when cells were cultured under hypoxic conditions. We concluded that increased oxidative stress plays a significant role in inducing podocyte protein shedding in preeclampsia.
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Affiliation(s)
- Yuping Wang
- Department of Obstetrics and Gynecology, Louisiana State University Health Sciences Center, Shreveport, Louisiana
| | - Shuang Zhao
- Department of Obstetrics and Gynecology, Louisiana State University Health Sciences Center, Shreveport, Louisiana
| | - Yang Gu
- Department of Obstetrics and Gynecology, Louisiana State University Health Sciences Center, Shreveport, Louisiana
| | - David F Lewis
- Department of Obstetrics and Gynecology, Louisiana State University Health Sciences Center, Shreveport, Louisiana
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160
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Li L, Yi Z, Xi H, Ma L, Shao H, Wang W, Pan H, Li M, Jiang H. Congenital nephrotic syndrome associated with 22q11.2 duplication syndrome in a Chinese family and functional analysis of the intronic NPHS1 c. 3286 + 5G > A mutation. Ital J Pediatr 2019; 45:109. [PMID: 31443662 PMCID: PMC6708249 DOI: 10.1186/s13052-019-0690-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 07/25/2019] [Indexed: 12/04/2022] Open
Abstract
Background Congenital nephrotic syndrome (CNS), which is defined as heavy proteinuria, hypoalbuminemia, hyperlipidemia and edema, is most caused by monogenic defects in structural proteins of the glomerular filtration barrier in the kidneys. 22q11.2 duplication syndrome was a chromosomal disease with variable clinical featuresranging from normal to mental retardation and with congenital defects. Co-occurrence of two genetic disorders in a single patient is rare. Case presentation The proband was born at 36 weeks of gestational age spontaneously and weighed 2350 g at birth. Six days after birth, the proband was admitted to our hospital due to fever of 38.5 °C lasting for 6 h. Physical examination at admission time showed dysmorphic features of hypertelorism, palpebral edema, broad nose bridge, upturned nose, dysmorphic auricle, long philtrum, and a thin upper lip. Additionally, we found left wrist drop and bilateral strephexopodia, bilateral knee joint flexion contracture in this patient. A series of indicators were detected and showed abnormalities. Albumin was used to remit the hypoproteinemia and edema. However, the parents refused to accept further therapy and the boy died at age 3 months due to cachexy. To confirm the pathogenesis, genetic analysis were performed and revealed two mutations of NPHS1 gene: Exon18: c.2386G > C; p. (Gly796Arg) inherited from mother, and intron24: c.3286 + 5G > A; p.? inherited from father. And he also had a 22q11.2 duplication which was inherited from his mild affected mother. The pathogenesis of the intronic mutation has been further identified that it can defect alternative splicing of NPHS1. Conclusions We present a patient who was caught in congenital nephrotic syndrome and 22q11.2 duplication syndrome simultaneously, emphasizing the importance of new sequencing technology on diagnosis of different genetic disorders.
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Affiliation(s)
- Liangliang Li
- Neonatal Department, The Affiliated Hospital of Qingdao University, NO.16 Jiangsu Road, Shinan District, Qingdao, 266003, Shandong, China
| | - Zhi Yi
- Neurological and Endocrine Department of Pediatric Center, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Hongmin Xi
- Neonatal Department, The Affiliated Hospital of Qingdao University, NO.16 Jiangsu Road, Shinan District, Qingdao, 266003, Shandong, China
| | - Lili Ma
- Neonatal Department, The Affiliated Hospital of Qingdao University, NO.16 Jiangsu Road, Shinan District, Qingdao, 266003, Shandong, China
| | - Hui Shao
- Neonatal Department, The Affiliated Hospital of Qingdao University, NO.16 Jiangsu Road, Shinan District, Qingdao, 266003, Shandong, China
| | - Wenwen Wang
- Intensive Care Unit, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Hong Pan
- Department of Central Laboratory, Peking University First Hospital, Beijing, China
| | - Miaomiao Li
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Hong Jiang
- Neonatal Department, The Affiliated Hospital of Qingdao University, NO.16 Jiangsu Road, Shinan District, Qingdao, 266003, Shandong, China.
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161
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Zhu X, Ye Y, Xu C, Gao C, Zhang Y, Zhou J, Lin W, Mao J. Protein phosphatase 2A modulates podocyte maturation and glomerular functional integrity in mice. Cell Commun Signal 2019; 17:91. [PMID: 31387591 PMCID: PMC6685276 DOI: 10.1186/s12964-019-0402-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 07/22/2019] [Indexed: 01/08/2023] Open
Abstract
Background Protein phosphorylation & dephosphorylation are ubiquitous cellular processes that allow for the nuanced and reversible regulation of protein activity. Protein phosphatase 2A (PP2A) is a multifunction phosphatase that is well expressed in all cell types of kidney during early renal development, though its functions in kidney remains to be elucidated. Methods PP2A conditional knock-out mice was generated with PP2A fl/fl mice that were crossed with Podocin-Cre mice. The phenotype of Pod-PP2A–KO mice (homozygous for the floxed PP2A allele with Podocin-Cre) and littermate PP2A fl/fl controls (homozygous for the PP2A allele but lacking Podocin-Cre) were further studied. Primary podocytes isolated from the Pod-PP2A-KO mice were cultured and they were then employed with sing label-free nano-LC − MS/MS technology on a Q-exactive followed by SIEVE processing to identify possible target molecular entities for the dephosphorylation effect of PP2A, in which Western blot and immunofluorescent staining were used to analyze further. Results Pod-PP2A–KO mice were developed with weight loss, growth retardation, proteinuria, glomerulopathy and foot process effacement, together with reduced expression of some slit diaphragm molecules and cytoskeleton rearrangement of podocytes. Y box protein 1 (YB-1) was identified to be the target molecule for dephosphorylation effect of PP2A. Furthermore, YB-1 phosphorylation was up-regulated in the Pod-PP2A–KO mice in contrast to the wild type controls, while total and un-phosphorylated YB-1 both was moderately down-regulated in podocytes from the Pod-PP2A-KO mice. Conclusion Our study revealed the important role of PP2A in regulating the development of foot processes and fully differentiated podocytes whereas fine-tuning of YB-1 via a post-translational modification by PP2A regulating its activity might be crucial for the functional integrity of podocytes and glomerular filtration barrier. Graphic abstract ![]()
Electronic supplementary material The online version of this article (10.1186/s12964-019-0402-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xiujuan Zhu
- Department of Nephrology, The Children Hospital of Zhejiang University School of Medicine, #57 Zhugan Lane, Hangzhou, 310003, Zhejiang Province, People's Republic of China
| | - Yuhong Ye
- Department of Nephrology, The Children Hospital of Zhejiang University School of Medicine, #57 Zhugan Lane, Hangzhou, 310003, Zhejiang Province, People's Republic of China
| | - Chengxian Xu
- Department of Nephrology, The Children Hospital of Zhejiang University School of Medicine, #57 Zhugan Lane, Hangzhou, 310003, Zhejiang Province, People's Republic of China
| | - Cunji Gao
- Chronic Disease Research Institute, Department of Nutrition and Food Hygiene, Zhejiang University School of Public Health, Hangzhou, 310058, Zhejiang Province, People's Republic of China
| | - Yingying Zhang
- Department of Nephrology, The Children Hospital of Zhejiang University School of Medicine, #57 Zhugan Lane, Hangzhou, 310003, Zhejiang Province, People's Republic of China
| | - Jing Zhou
- Harvard Center for Polycystic Kidney Disease Research and Renal Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA02115, USA
| | - Weiqiang Lin
- Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou, 310058, Zhejiang Province, People's Republic of China.
| | - Jianhua Mao
- Department of Nephrology, The Children Hospital of Zhejiang University School of Medicine, #57 Zhugan Lane, Hangzhou, 310003, Zhejiang Province, People's Republic of China.
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Kalantari S, Naji M, Nafar M, Yazdani-Kachooei H, Borumandnia N, Parvin M. Chondroitin sulfate degradation and eicosanoid metabolism pathways are impaired in focal segmental glomerulosclerosis: Experimental confirmation of an in silico prediction. ACTA ACUST UNITED AC 2019; 9:89-95. [PMID: 31334040 PMCID: PMC6637215 DOI: 10.15171/bi.2019.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 12/16/2018] [Accepted: 12/22/2018] [Indexed: 11/09/2022]
Abstract
Introduction: Focal segmental glomerulosclerosis (FSGS), the most common primary glomerular disease, is a diverse clinical entity that occurs after podocyte injury. Although numerous studies have suggested molecular pathways responsible for the development of FSGS, many still remain unknown about its pathogenic mechanisms. Two important pathways were predicted as candidates for the pathogenesis of FSGS in our previous in silico analysis, whom we aim to confirm experimentally in the present study. Methods: The expression levels of 4 enzyme genes that are representative of "chondroitin sulfate degradation" and "eicosanoid metabolism" pathways were investigated in the urinary sediments of biopsy-proven FSGS patients and healthy subjects using real-time polymerase chain reaction (RT-PCR). These target genes were arylsulfatase, hexosaminidase, cyclooxygenase-2 (COX-2), and prostaglandin I2 synthase. The patients were sub-divided into 2 groups based on the range of proteinuria and glomerular filtration rate and were compared for variation in the expression of target genes. Correlation of target genes with clinical and pathological characteristics of the disease was calculated and receiver operating characteristic (ROC) analysis was performed. Results: A combined panel of arylsulfatase, hexosaminidase, and COX-2 improved the diagnosis of FSGS by 76%. Hexosaminidase was correlated with the level of proteinuria, while COX-2 was correlated with interstitial inflammation and serum creatinine level in the disease group. Conclusion: Our data supported the implication of these target genes and pathways in the pathogenesis of FSGS. In addition, these genes can be considered as non-invasive biomarkers for FSGS.
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Affiliation(s)
- Shiva Kalantari
- Chronic Kidney Disease Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Naji
- Urology-Nephrology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohsen Nafar
- Urology-Nephrology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hootan Yazdani-Kachooei
- Department of Biology, Faculty of Basic Sciences, Islamic Azad University, Science and Research Branch, Tehran, Iran
| | - Nasrin Borumandnia
- Urology-Nephrology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mahmoud Parvin
- Department of Pathology, Shahid Labbafinejad Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Rachubik P, Piwkowska A. The role of vasodilator‐stimulated phosphoprotein in podocyte functioning. Cell Biol Int 2019; 43:1092-1101. [DOI: 10.1002/cbin.11149] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 04/06/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Patrycja Rachubik
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research CentrePolish Academy of Sciences Wita Stwosza 63, 80‐308 Gdańsk Poland
| | - Agnieszka Piwkowska
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research CentrePolish Academy of Sciences Wita Stwosza 63, 80‐308 Gdańsk Poland
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164
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Evaluation of the urinary podocalyxin and nephrin excretion levels to determine a safe time interval between two sessions of SWL for renal stones: a non randomized exploratory study. Int Urol Nephrol 2019; 51:1727-1734. [PMID: 31321677 DOI: 10.1007/s11255-019-02229-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 07/05/2019] [Indexed: 10/26/2022]
Abstract
OBJECTIVES We aimed to evaluate the role of nephrin and podocalyxin in determining the intervals between shock wave lithotripsy (SWL) sessions and how soon the kidney damage was recovered. METHODS This work was a prospective study that included 30 patients with unilateral kidney stones. The patients' midflow urine samples were collected before SWL and 1 h, 1 day and 1 week after the procedure. Nephrin and podocalyxin levels in the urine samples were measured by the enzyme-linked immunosorbent assay method. RESULTS Among the 30 patients who underwent SWL, 19 were males and 11 were females. The mean age of the SWL group was 34.7 ± 13.2. Both biomarkers did not correlate with age, creatinine values, body mass index, stone side, stone size, energy, frequency and shock numbers. Nephrin and podocalyxin levels were significantly higher at the pre-SWL point (p < 0.05). After the procedure, a significant decrease was observed in both biomarker levels (p < 0.05). At the end of first day, these levels started to increase progressively up to the end of the first week (p > 0.05). CONCLUSIONS Nephrin and podocalyxin may help to determine early period kidney damage associated with SWL. Post-SWL podocalyxin and nephrin values may be used to determine the interval between SWL sessions.
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165
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Tossidou I, Teng B, Worthmann K, Müller-Deile J, Jobst-Schwan T, Kardinal C, Schroder P, Bolanos-Palmieri P, Haller H, Willerding J, Drost DM, de Jonge L, Reubold T, Eschenburg S, Johnson RI, Schiffer M. Tyrosine Phosphorylation of CD2AP Affects Stability of the Slit Diaphragm Complex. J Am Soc Nephrol 2019; 30:1220-1237. [PMID: 31235616 DOI: 10.1681/asn.2018080860] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 04/18/2019] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND CD2-associated protein (CD2AP), a slit diaphragm-associated scaffolding protein involved in survival and regulation of the cytoskeleton in podocytes, is considered a "stabilizer" of the slit diaphragm complex that connects the slit diaphragm protein nephrin to the cytoskeleton of the cell. Tyrosine phosphorylation of slit diaphragm molecules can influence their surface expression, but it is unknown whether tyrosine phosphorylation events of CD2AP are also physiologically relevant to slit diaphragm stability. METHODS We used isoelectric focusing, western blot analysis, and immunofluorescence to investigate phosphorylation of CD2AP, and phospho-CD2AP antibodies and site-directed mutagenesis to define the specific phosphorylated tyrosine residues. We used cross-species rescue experiments in Cd2apKD zebrafish and in Drosophila cindrRNAi mutants to define the physiologic relevance of CD2AP phosphorylation of the tyrosine residues. RESULTS We found that VEGF-A stimulation can induce a tyrosine phosphorylation response in CD2AP in podocytes, and that these phosphorylation events have an important effect on slit diaphragm protein localization and functionality in vivo. We demonstrated that tyrosine in position Y10 of the SH3-1 domain of CD2AP is indispensable for CD2AP function in vivo. We found that the binding affinity of nephrin to CD2AP is significantly enhanced in the absence of Y10; however, unexpectedly, this increased affinity leads not to stabilization but to functional impairment of the glomerular filtration barrier. CONCLUSIONS Our findings provide insight into CD2AP and its phosphorylation in the context of slit diaphragm functionality, and indicate a fine-tuned affinity balance of CD2AP and nephrin that is influenced by receptor tyrosine kinase stimulation.
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Affiliation(s)
- Irini Tossidou
- Division of Nephrology and Hypertension, Department of Medicine
| | - Beina Teng
- Department of Nephrology and Hypertension, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | | | - Janina Müller-Deile
- Division of Nephrology and Hypertension, Department of Medicine.,Department of Nephrology and Hypertension, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Tilman Jobst-Schwan
- Department of Nephrology and Hypertension, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | | | - Patricia Schroder
- Division of Nephrology and Hypertension, Department of Medicine.,Mount Desert Island Biological Laboratory, Salisbury Cove, Maine; and
| | - Patricia Bolanos-Palmieri
- Department of Nephrology and Hypertension, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Hermann Haller
- Division of Nephrology and Hypertension, Department of Medicine.,Mount Desert Island Biological Laboratory, Salisbury Cove, Maine; and
| | - Jonas Willerding
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Dana M Drost
- Department of Biology, Wesleyan University, Middletown, Connecticut
| | - Laura de Jonge
- Department of Biology, Wesleyan University, Middletown, Connecticut
| | - Thomas Reubold
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Susanne Eschenburg
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Ruth I Johnson
- Department of Biology, Wesleyan University, Middletown, Connecticut
| | - Mario Schiffer
- Division of Nephrology and Hypertension, Department of Medicine, .,Department of Nephrology and Hypertension, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Mount Desert Island Biological Laboratory, Salisbury Cove, Maine; and
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166
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Zhuo L, Huang L, Yang Z, Li G, Wang L. A comprehensive analysis of NPHS1 gene mutations in patients with sporadic focal segmental glomerulosclerosis. BMC MEDICAL GENETICS 2019; 20:111. [PMID: 31216994 PMCID: PMC6585123 DOI: 10.1186/s12881-019-0845-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Accepted: 06/06/2019] [Indexed: 01/01/2023]
Abstract
BACKGROUND Focal segmental glomerulosclerosis (FSGS) is still one of the common causes of refractory nephrotic syndrome. Nephrin, encoded by podocyte-specific NPHS1 gene, participated in the pathogenesis of FSGS. The sites of NPHS1 mutations in FSGS is not clarified very well. In this study, we investigated the specific mutations of NPHS1 gene in Chinese patients with sporadic FSGS. METHODS A total of 309 patients with sporadic FSGS were collected and screened for NPHS1 mutations by second-generation sequencing. The variants were compared with those extracted from 2504 healthy controls in the 1000 Genomes Project. The possible pathogenic roles of missense variants were predicted by three different software. We also compared these candidate causal mutations with those summarized from the previous studies. RESULTS Thirty-two genetic mutations of NPHS1 gene were identified in FSGS patients, including 12 synonymous mutations, 17 missense mutations, 1 splicing mutation, and 2 intron mutations, of which c.G3315A (p.S1105S) was the most common variant (261/309). A novel missense mutation c.G2638 T (p.V880F) and a novel splicing mutation 35830957 C > T were identified in FSGS patients. The frequencies of the four synonymous mutations (c.C294T [p.I98I], c.C2223T [p.T741 T], c.C2289T [p.V763 V], c.G3315A [p.S1105S]) were much higher in FSGS patients than in controls. The frequencies of the four missense mutations (c.G349A [p.E117K], c.G1339A [p.E447K], c.G1802C [p.G601A], c.C2398T [p.R800C]) were much higher and one (c.A3230G [p.N1077S]) was lower in FSGS patients than in controls. Five missense mutations, c.C616A (p.P206T), c.G1802C (p.G601A), c.C2309T (p.P770L), c.G2869C (p.V957 L), and c.C3274T (p.R1092C), were predicted to be pathogenic mutations by software analysis. CONCLUSIONS NPHS1 gene mutations were quite common in sporadic FSGS patients. We strongly recommend mutation analysis of the NPHS1 gene in the clinical management of FSGS patients.
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Affiliation(s)
- Ling Zhuo
- Renal Department and Institute of Nephrology, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, No. 32, West 2nd Duan, 1st Circle Road, Qingyang District, Chengdu, Sichuan, 610072, People's Republic of China
| | - Lulin Huang
- Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072, China
| | - Zhenglin Yang
- Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072, China
| | - Guisen Li
- Renal Department and Institute of Nephrology, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, No. 32, West 2nd Duan, 1st Circle Road, Qingyang District, Chengdu, Sichuan, 610072, People's Republic of China.
| | - Li Wang
- Renal Department and Institute of Nephrology, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, No. 32, West 2nd Duan, 1st Circle Road, Qingyang District, Chengdu, Sichuan, 610072, People's Republic of China
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167
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Yoshimura Y, Nishinakamura R. Podocyte development, disease, and stem cell research. Kidney Int 2019; 96:1077-1082. [PMID: 31420196 DOI: 10.1016/j.kint.2019.04.044] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 04/04/2019] [Accepted: 04/23/2019] [Indexed: 12/18/2022]
Abstract
The glomerular podocyte is one of the major targets of kidney research. Recent establishment of kidney organoids from pluripotent stem cells has enabled the detailed analysis of human podocytes in both development and disease. The podocytes in organoids express slit diaphragm-related genes and proteins and exhibit characteristic morphology, especially upon experimental transplantation. Organoid technology is now used to reproduce hereditary podocyte diseases, and selective podocyte induction methods have also been reported. Moreover, single-cell RNA-sequencing of human fetal and adult kidneys has revealed the detailed molecular features of this cell lineage, as well as serving as references for kidney organoids in which podocytes are still immature. Here, we discuss the recent progress and limitations of podocyte research from the viewpoint of developmental biology and kidney organoids.
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Affiliation(s)
- Yasuhiro Yoshimura
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Japan; Department of Nephrology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Ryuichi Nishinakamura
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Japan.
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Espiritu EB, Jiang H, Moreau-Marquis S, Sullivan M, Yan K, Beer Stolz D, Sampson MG, Hukriede NA, Swiatecka-Urban A. The human nephrin Y 1139RSL motif is essential for podocyte foot process organization and slit diaphragm formation during glomerular development. J Biol Chem 2019; 294:10773-10788. [PMID: 31152064 DOI: 10.1074/jbc.ra119.008235] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 05/16/2019] [Indexed: 11/06/2022] Open
Abstract
Nephrin is an immunoglobulin-type cell-adhesion molecule with a key role in the glomerular interpodocyte slit diaphragm. Mutations in the nephrin gene are associated with defects in the slit diaphragm, leading to early-onset nephrotic syndrome, typically resistant to treatment. Although the endocytic trafficking of nephrin is essential for the assembly of the slit diaphragm, nephrin's specific endocytic motifs remain unknown. To search for endocytic motifs, here we performed a multisequence alignment of nephrin and identified a canonical YXXØ-type motif, Y1139RSL, in the nephrin cytoplasmic tail, expressed only in primates. Using site-directed mutagenesis, various biochemical methods, single-plane illumination microscopy, a human podocyte line, and a human nephrin-expressing zebrafish model, we found that Y1139RSL is a novel endocytic motif and a structural element for clathrin-mediated nephrin endocytosis that functions as a phosphorylation-sensitive signal. We observed that Y1139RSL motif-mediated endocytosis helps to localize nephrin to specialized plasma membrane domains in podocytes and is essential for normal foot process organization into a functional slit diaphragm between neighboring foot processes in zebrafish. The importance of nephrin Y1139RSL for healthy podocyte development was supported by population-level analyses of genetic variations at this motif, revealing that such variations are very rare, suggesting that mutations in this motif have autosomal-recessive negative effects on kidney health. These findings expand our understanding of the mechanism underlying nephrin endocytosis and may lead to improved diagnostic tools or therapeutic strategies for managing early-onset, treatment-resistant nephrotic syndrome.
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Affiliation(s)
- Eugenel B Espiritu
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15201
| | - Huajun Jiang
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15224
| | - Sophie Moreau-Marquis
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755
| | - Mara Sullivan
- Department of Nephrology, UPMC Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15201
| | - Kunimasa Yan
- Department of Pediatrics, Kyorin University School of Medicine, Mitaka, Tokyo 181-8611, Japan, and
| | - Donna Beer Stolz
- Department of Nephrology, UPMC Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15201
| | - Matthew G Sampson
- Department of Pediatrics-Nephrology University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Neil A Hukriede
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15201
| | - Agnieszka Swiatecka-Urban
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15224,.
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Mulukala Narasimha SK, Kar PP, Vadrevu R, Pasupulati AK. Intrinsically disordered regions mediate macromolecular assembly of the Slit diaphragm proteins associated with Nephrotic syndrome. MOLECULAR SIMULATION 2019. [DOI: 10.1080/08927022.2019.1570508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
| | - Prajna Parimita Kar
- Laboratory of Molecular Interactions, National Institute of Animal Biotechnology, Hyderabad, India
| | - Ramakrishna Vadrevu
- Department of Biological Sciences, BITS-Pilani, Hyderabad Campus, Hyderabad, India
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170
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Angiotensin II-mediated MYH9 downregulation causes structural and functional podocyte injury in diabetic kidney disease. Sci Rep 2019; 9:7679. [PMID: 31118506 PMCID: PMC6531474 DOI: 10.1038/s41598-019-44194-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 05/10/2019] [Indexed: 12/26/2022] Open
Abstract
MYH9, a widely expressed gene encoding nonmuscle myosin heavy chain, is also expressed in podocytes and is associated with glomerular pathophysiology. However, the mechanisms underlying MYH9-related glomerular diseases associated with proteinuria are poorly understood. Therefore, we investigated the role and mechanism of MYH9 in diabetic kidney injury. MYH9 expression was decreased in glomeruli from diabetic patients and animals and in podocytes treated with Ang II in vitro. Ang II treatment and siRNA-mediated MYH9 knockdown in podocytes resulted in actin cytoskeleton reorganization, reduced cell adhesion, actin-associated protein downregulation, and increased albumin permeability. Ang II treatment increased NOX4 expression and ROS generation. The Ang II receptor blocker losartan and the ROS scavenger NAC restored MYH9 expression in Ang II-treated podocytes, attenuated disrupted actin cytoskeleton and decreased albumin permeability. Furthermore, MYH9 overexpression in podocytes restored the effects of Ang II on the actin cytoskeleton and actin-associated proteins. Ang II-mediated TRPC6 activation reduced MYH9 expression. These results suggest that Ang II-mediated MYH9 depletion in diabetic nephropathy may increase filtration barrier permeability by inducing structural and functional podocyte injury through TRPC6-mediated Ca2+ influx by NOX4-mediated ROS generation. These findings reveal a novel MYH9 function in maintaining urinary filtration barrier integrity. MYH9 may be a potential target for treating diabetic nephropathy.
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171
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Zhang WN, Yang L, He SS, Qin XM, Li AP. Metabolomics coupled with integrative pharmacology reveal the protective effect of FangjiHuangqi Decoction against adriamycin-induced rat nephropathy model. J Pharm Biomed Anal 2019; 174:525-533. [PMID: 31252309 DOI: 10.1016/j.jpba.2019.05.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 04/16/2019] [Accepted: 05/11/2019] [Indexed: 01/23/2023]
Abstract
With the development of the society, the number of people who got the nephrotic syndrome (NS) is going up roughly. Therefore, finding a better way to treat NS is becoming a major global public health issue. As we all know, traditional Chinese medicine (TCM), especially Fangji Huangqi Decoction (FHD), has a long history and has good curative effects on NS. However, the mechanism of FHD treating NS has not been clearly elucidated. To address this problem, a feasible system was developed by metabolomics and integrative pharmacology approach. To study the mechanisms of Chinese medical formula FHD treating NS based on metabolomics and integrative pharmacology. In this study, a NMR based metabolomics approach coupled with biochemical assay and Western Blot had been employed to study the protective effect of FHD against adriamycin-induced nephropathy using rat model. And we proposed a integrative pharmacology-based method, which combined chemical ingredients database building, target identification and network analysis. These were aimed to decipher the mechanisms of action for the FHD in NS treatment. Multivariate analysis revealed that 13 of 16 perturbed metabolites could be reversed by FHD, and the MetaboAnalyst analysis revealed that the anti-nephrotic syndrome effect of FHD was probably related with regulation of alanine, aspartate and glutamate metabolism, citrate cycle, pyruvate metabolism, cysteine and methionine metabolism and glyoxylate and dicarboxylate metabolism. The integrative pharmacology analysis revealed 93 potential targets for FHD, and suggested that the protective effect of FHD on the nephrotic syndrome was probably related with the regulation of immune, and energy metabolic and fatty acid metabolic. In addition, both the metabolomics and the integrative pharmacology are focus together on the alanine, aspartate and glutamate metabolism pathway. These metabolites changes and the core targets changes, as well as the metabolite-target pathway network provide insights into the mechanisms of FHD treating nephrotic syndrome, and further studies are needed to validate the bioactive compounds responsible for the anti-nephrotic syndrome effect of FHD.
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Affiliation(s)
- Wang-Ning Zhang
- Modern Research Center for Traditional Chinese Medicine of Shanxi University, No. 92, Wucheng Road, Taiyuan, 030006, Shanxi, People's Republic of China
| | - Liu Yang
- College of Chemistry and Chemical Engineering of Shanxi University, No. 92, Wucheng Road, Taiyuan, 030006, Shanxi, People's Republic of China
| | - Sheng-Sheng He
- College of Chemistry and Chemical Engineering of Shanxi University, No. 92, Wucheng Road, Taiyuan, 030006, Shanxi, People's Republic of China
| | - Xue-Mei Qin
- Modern Research Center for Traditional Chinese Medicine of Shanxi University, No. 92, Wucheng Road, Taiyuan, 030006, Shanxi, People's Republic of China.
| | - Ai-Ping Li
- Modern Research Center for Traditional Chinese Medicine of Shanxi University, No. 92, Wucheng Road, Taiyuan, 030006, Shanxi, People's Republic of China.
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Ji L, Chen Y, Wang H, Zhang W, He L, Wu J, Liu Y. Overexpression of Sirt6 promotes M2 macrophage transformation, alleviating renal injury in diabetic nephropathy. Int J Oncol 2019; 55:103-115. [PMID: 31115579 PMCID: PMC6561622 DOI: 10.3892/ijo.2019.4800] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 03/01/2019] [Indexed: 02/06/2023] Open
Abstract
In this study, we aimed to investigate the associations between Sirt6, macrophages and diabetic nephropathy (DN). Immunohistochemical, western blot and RT-qPCR analyses were performed to detect the expression levels of Sirt6, the markers of podocytes and monocytes and related inflammatory factors in the tissues of rats with streptozocin-induced DN. A series of cell experiments in isolated culture or the co-culture of macrophages and podocytes were conducted to examine the effects of the overexpression of Sirt6 on macrophage transformation, podocyte apoptosis and associated genes, and analyses were performed using RT-qPCR, flow cytometry and western blot analysis, where appropriate. In the rat model of DN, injured podocytes were represented by the decreased protein expression levels of Nephrin and Sirt6, and by an increased Desmin expression. Additionally, the M1 phenotype transformation of macrophages was evidenced by the increased expression levels of CD86, tumor necrosis factor (TNF)-α and inducible nitric oxide synthase (iNOS), and by the decreased expression levels of CD206, Sirt6, interleukin (IL)-4 and IL-10. In vitro assays of macrophages and podocytes demonstrated that glucose promoted macrophage M1 transformation and podocyte apoptosis in a dose-dependent manner and attenuated Sirt6 expression. Macrophages transformed into the M2 phenotype following the overexpression of Sirt6 by the successful transfection of macrophages with a Sirt6 overexpression plasmid. Sirt6 was also overexpressed in podocytes. In a Transwell co-culture system, the overexpression of Sirt6 in macrophages (but not the overexpression of Sirt6 in podocytes) protected the podocytes from high-glucose-induced injury. However, the apoptosis of the podocytes overexpressing Sirt6 (induced by transfection with a Sirt6 overexpression plasmid) still increased when these podocytes were co-cultured with macrophages in high-glucose medium. These protective effects were evidenced by the inhibition of apoptosis, the upregulation of the expression levels of Bcl-2 and CD206, as well as by the decreased expression levels of Bax and CD86. On the whole, the findings of this study suggest that Sirt6 protects podocytes against injury in a mimicked diabetic kidney microenvironment by activating M2 macrophages, indicating that Sirt6 can act as an immune response regulatory factor in DN-associated renal inflammatory injury.
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Affiliation(s)
- Liqiang Ji
- Department of Pharmacy, The First People's Hospital of Yuhang District, Hangzhou, Zhejiang 311100, P.R China
| | - Yifang Chen
- Department of Pharmacy, The First People's Hospital of Yuhang District, Hangzhou, Zhejiang 311100, P.R China
| | - Hongqiang Wang
- Department of Pharmacy, Hangzhou Yuhang TCM Hospital, Hangzhou, Zhejiang 311106, P.R China
| | - Wei Zhang
- Department of Pharmacy, The First People's Hospital of Yuhang District, Hangzhou, Zhejiang 311100, P.R China
| | - Lanxiang He
- Department of Pharmacy, The First People's Hospital of Yuhang District, Hangzhou, Zhejiang 311100, P.R China
| | - Jingmin Wu
- Department of Pharmacy, The First People's Hospital of Yuhang District, Hangzhou, Zhejiang 311100, P.R China
| | - Yinghui Liu
- Department of Endocrinology, Zhejiang Provincial Integrated Chinese and Western Medicine Hospital, Hangzhou Red Cross Hospital, Hangzhou, Zhejiang 310003, P.R China
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173
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Kawasaki Y, Matsumoto A, Miyaki T, Kinoshita M, Kakuta S, Sakai T, Ichimura K. Three-dimensional architecture of pericardial nephrocytes in Drosophila melanogaster revealed by FIB/SEM tomography. Cell Tissue Res 2019; 378:289-300. [PMID: 31089884 DOI: 10.1007/s00441-019-03037-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 04/15/2019] [Indexed: 01/07/2023]
Abstract
Nephrocytes are similar in structure to podocytes and play a role in the isolation of toxic substances from hemolymph in insects. Drosophila melanogaster nephrocytes have recently been used to study podocyte function and disease. However, the three-dimensional ultrastructure of nephrocytes is not clearly understood because their surrounding basement membrane makes it difficult to observe using conventional scanning electron microscopy. We reconstructed the three-dimensional ultrastructure of Drosophila pericardial nephrocytes using serial focused-ion beam/scanning electron microscopy (FIB/SEM) images. The basal surfaces were occupied by foot processes and slit-like spaces between them. The slit-like spaces corresponded to the podocyte filtration slits and were formed by longitudinal infolding/invagination of the basal plasma membrane. The basal surface between the slit-like spaces became the foot processes, which ran almost linearly, and had a "washboard-like" appearance. Both ends of the foot processes were usually anastomosed to neighboring foot processes and thus free ends were rarely observed. We demonstrated that FIB/SEM is a powerful tool to better understand the three-dimensional architecture of nephrocytes.
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Affiliation(s)
- Yuto Kawasaki
- Department of Anatomy and Life Structure, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Akira Matsumoto
- Department of Biology, Juntendo University School of Medicine, Inzai, Chiba, Japan
| | - Takayuki Miyaki
- Department of Anatomy and Life Structure, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Mui Kinoshita
- Department of Anatomy and Life Structure, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Soichiro Kakuta
- Laboratory of Morphology and Image Analysis, Center for Biomedical Research Resources, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Tatsuo Sakai
- Department of Anatomy and Life Structure, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Koichiro Ichimura
- Department of Anatomy and Life Structure, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan. .,Laboratory of Morphology and Image Analysis, Center for Biomedical Research Resources, Juntendo University Graduate School of Medicine, Tokyo, Japan.
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174
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Anigilaje EA, Olutola A. Prospects of genetic testing for steroid-resistant nephrotic syndrome in Nigerian children: a narrative review of challenges and opportunities. Int J Nephrol Renovasc Dis 2019; 12:119-136. [PMID: 31190951 PMCID: PMC6512787 DOI: 10.2147/ijnrd.s193874] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The prevalence of childhood steroid-resistant nephrotic syndrome (SRNS) ranges from 35% to 92%. This steroid resistance among Nigerian children also reflects underlying renal histopathology, revealing a rare minimal-change disease and a varying burden of membranoproliferative glomerulonephritis and focal segmental glomerulosclerosis (FSGS). FSGS tends to progress to end-stage kidney disease, which requires dialysis and/or renal transplantation. While knowledge of the molecular basis of NS is evolving, recent data support the role of mutant genes that otherwise maintain the structural and functional composition of the glomerular filtration barrier to account for many monogenic forms of FSGS. With the advent of next-generation sequencing, >39 genes are currently associated with SRNS, and the number is likely to increase in the near future. Monogenic FSGS is primarily resistant to steroids, and this foreknowledge obviates the need for steroids, other immunosuppressive therapy, and renal biopsy. Therefore, a multidisciplinary collaboration among cell biologists, molecular physiologists, geneticists, and clinicians holds prospects of fine-tuning the management of SRNS caused by known mutant genes. This article describes the genetics of NS/SRNS in childhood and also gives a narrative review of the challenges and opportunities for molecular testing among children with SRNS in Nigeria. For these children to benefit from genetic diagnosis, Nigeria must aspire to have and develop the manpower and infrastructure required for medical genetics and genomic medicine, leveraging on her existing experiences in genomic medicine. Concerted efforts can be put in place to increase the number of enrollees in Nigeria’s National Health Insurance Scheme (NHIS). The scope of the NHIS can be expanded to cater for the expensive bill of genetic testing within or outside the structure of the National Renal Care Policy proposed by Nigerian nephrologists.
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Affiliation(s)
- Emmanuel Ademola Anigilaje
- Nephrology Unit, Department of Paediatrics, Faculty of Clinical Sciences, College of Health Sciences, University of Abuja, Abuja, Nigeria,
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175
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Odenthal J, Brinkkoetter PT. Drosophila melanogaster and its nephrocytes: A versatile model for glomerular research. Methods Cell Biol 2019; 154:217-240. [PMID: 31493819 DOI: 10.1016/bs.mcb.2019.03.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Glomerular disorders are a predominant cause of chronic kidney diseases and end-stage renal failure. Especially podocytes, epithelial cells which represent the outermost part of the filtration barrier, are affected by disease and experience a gradual loss of function. Despite recent advances in identifying potential pathways underlying podocyte injury, treatment remains challenging. It is therefore desirable to employ suitable model organisms in order to study glomerular disease and elucidate affected pathways. Due to its diverse ways of genetic manipulation and high genomic conservation, Drosophila melanogaster is a powerful model organism for biomedical research. The fly was recently used to assess podocytopathies by exploiting the nephrocyte system. Nephrocytes are spherical cells within the body cavity of the fly responsible for detoxification and clearance of unwanted substances. More importantly, they share many characteristics with mammalian podocytes. Here, we summarize how to use Drosophila as a model organism for podocyte research. We discuss examples of techniques that can be used to genetically manipulate nephrocytes and provide protocols for nephrocyte isolation and for morphological as well as functional analysis.
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Affiliation(s)
- Johanna Odenthal
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; CECAD, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Paul Thomas Brinkkoetter
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; CECAD, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
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The Role of p.Ser1105Ser (in NPHS1 Gene) and p.Arg548Leu (in PLCE1 Gene) with Disease Status of Vietnamese Patients with Congenital Nephrotic Syndrome: Benign or Pathogenic? ACTA ACUST UNITED AC 2019; 55:medicina55040102. [PMID: 31013750 PMCID: PMC6524047 DOI: 10.3390/medicina55040102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 04/11/2019] [Accepted: 04/11/2019] [Indexed: 11/20/2022]
Abstract
Background and Objectives: Congenital nephrotic syndrome (CNS), a genetic disease caused by mutations in genes on autosomes, usually occurs in the first three months after birth. A number of genetic mutations in genes, which encode for the components of the glomerular filtration barrier have been identified. We investigated mutations in NPHS1, NPHS2, PLCE1 (NPHS3), and WT1 genes that relate to the disease in Vietnamese patients. Materials and Methods: We performed genetic analysis of two unrelated patients, who were diagnosed with CNS in the Vietnam National Children’s Hospital with different disease status. The entire coding region and adjacent splice sites of these genes were amplified and sequenced using the Sanger method. The sequencing data were analyzed and compared with the NPHS1, NPHS2, PLCE1, and WT1 gene sequences published in Ensembl (ENSG00000161270, ENSG00000116218, ENSG00000138193, and ENSG00000184937, respectively) using BioEdit software to detect mutations. Results: We detected a new variant p.Ser607Arg and two other (p.Glu117Lys and p.Ser1105Ser) in the NPHS1 gene, as well as two variants (p.Arg548Leu, p.Pro1575Arg) in the PLCE1 gene. No mutations were detected in the NPHS2 and WT1 genes. Patient 1, who presented a heterozygous genotype of p.Ser1105Ser and p.Arg548Leu had a mild disease status but patient 2, who presented a homozygous genotype of these alleles, had a severe phenotype. Conclusions: These results suggest that variants p.Ser1105Ser (in NPHS1 gene) and p.Arg548Leu (in PLCE1 gene) in the homozygous form might play a role in the development of the disease in patients.
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177
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Chen Y, Lin L, Tao X, Song Y, Cui J, Wan J. The role of podocyte damage in the etiology of ischemia-reperfusion acute kidney injury and post-injury fibrosis. BMC Nephrol 2019; 20:106. [PMID: 30922260 PMCID: PMC6438002 DOI: 10.1186/s12882-019-1298-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 03/17/2019] [Indexed: 01/07/2023] Open
Abstract
Background To establish a model of chronic renal fibrosis following acute kidney injury (AKI) in BALB/c mice and to observe the effect of AKI on podocyte injury and chronic fibrosis of the kidney. Additional aims included using the model to explore the role of podocyte injury in AKI and post-injury fibrosis. Methods Fifty BALB/C mice were randomly divided into control group (Ctr), sham group (sham), AKI 20 group (renal ischemia, 20 min reperfusion), AKI 30 group (renal ischemia, 30 min reperfusion) and AKI 40 group (renal ischemia, 40 min reperfusion). Mice serum and 24-h urine were collected on the 8th, 9th, 10th, 14th, and 28th days for urinary protein, serum creatinine (Scr) and blood urea nitrogen (BUN) analysis. HE staining, transmission electron microscopy (TEM), Masson staining, Q-PCR, Western Blot and immunohistochemistry were applied. Results Serum Scr and BUN levels across all AKI groups at the 9th day were significantly higher (P < 0.05) than controls, with higher reperfusion groups maintaining that increase up to 28 days (P < 0.05). Compared with Ctr group, the urinary protein of the AKI 40 group significantly rose on the 9th day (P < 0.05), normalizing immediately on the 10th day (P < 0.05). In contrast, the AKI 30 group rose significantly on the 14th day (P < 0.05) maintaining elevated levels for two weeks (P < 0.05). HE staining demonstrated ischemia-dependent renal tissue damage was aggravated in the mild to aggravated AKI groups. Mesangial proliferation, glomerulosclerosis, and tubulointerstitial pathology were also significantly increased in these groups (P < 0.05). Masson staining further showed that glomerular, renal tubular, and interstitial collagen were increased by ischemia in a time-dependent manner. Transmission EM additionally that podocytes of the mild to severe AKI groups displayed extensive fusion, exfoliation and GBM exposure. Synaptopodin, Nephrin, and CD2AP mRNA and protein expression demonstrated ischemic time-dependent decreases, while the TRPC6 was increased. There was a significant difference in the levels of Synaptopodin, Nephrin, CD2AP, and TRPC6 between the mild and severe AKI groups (P < 0.05). Conclusions 1) During the AKI process mice podocyte injury, proteinuria and the subsequent progression into chronic renal fibrosis is observed.2) Podocyte injury may be one of the causes of ischemia-reperfusion acute kidney injury and post-injury fibrosis. Electronic supplementary material The online version of this article (10.1186/s12882-019-1298-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yi Chen
- Department of Nephrology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350005, China
| | - Liyu Lin
- Department of Nephrology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350005, China
| | - Xuan Tao
- Department of Pathology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Yankun Song
- Department of Pathology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Jiong Cui
- Department of Nephrology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350005, China
| | - Jianxin Wan
- Department of Nephrology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350005, China.
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178
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Zhao F, Zhu JY, Richman A, Fu Y, Huang W, Chen N, Pan X, Yi C, Ding X, Wang S, Wang P, Nie X, Huang J, Yang Y, Yu Z, Han Z. Mutations in NUP160 Are Implicated in Steroid-Resistant Nephrotic Syndrome. J Am Soc Nephrol 2019; 30:840-853. [PMID: 30910934 DOI: 10.1681/asn.2018080786] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 02/02/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Studies have identified mutations in >50 genes that can lead to monogenic steroid-resistant nephrotic syndrome (SRNS). The NUP160 gene, which encodes one of the protein components of the nuclear pore complex nucleoporin 160 kD (Nup160), is expressed in both human and mouse kidney cells. Knockdown of NUP160 impairs mouse podocytes in cell culture. Recently, siblings with SRNS and proteinuria in a nonconsanguineous family were found to carry compound-heterozygous mutations in NUP160. METHODS We identified NUP160 mutations by whole-exome and Sanger sequencing of genomic DNA from a young girl with familial SRNS and FSGS who did not carry mutations in other genes known to be associated with SRNS. We performed in vivo functional validation studies on the NUP160 mutations using a Drosophila model. RESULTS We identified two compound-heterozygous NUP160 mutations, NUP160R1173× and NUP160E803K . We showed that silencing of Drosophila NUP160 specifically in nephrocytes (fly renal cells) led to functional abnormalities, reduced cell size and nuclear volume, and disorganized nuclear membrane structure. These defects were completely rescued by expression of the wild-type human NUP160 gene in nephrocytes. By contrast, expression of the NUP160 mutant allele NUP160R1173× completely failed to rescue nephrocyte phenotypes, and mutant allele NUP160E803K rescued only nuclear pore complex and nuclear lamin localization defects. CONCLUSIONS Mutations in NUP160 are implicated in SRNS. Our findings indicate that NUP160 should be included in the SRNS diagnostic gene panel to identify additional patients with SRNS and homozygous or compound-heterozygous NUP160 mutations and further strengthen the evidence that NUP160 mutations can cause SRNS.
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Affiliation(s)
- Feng Zhao
- Department of Pediatrics, Fuzhou Dongfang Hospital, Fujian, People's Republic of China.,Center for Genetic Medicine Research, Children's National Health System, Washington, DC.,Department of Pediatrics, Affiliated Dongfang Hospital, Xiamen University, Fujian, People's Republic of China.,Department of Pediatrics, Fuzhou Clinical Medical College, Fujian Medical University, Fujian, People's Republic of China
| | - Jun-Yi Zhu
- Center for Genetic Medicine Research, Children's National Health System, Washington, DC
| | - Adam Richman
- Center for Genetic Medicine Research, Children's National Health System, Washington, DC
| | - Yulong Fu
- Center for Genetic Medicine Research, Children's National Health System, Washington, DC
| | - Wen Huang
- Center for Genetic Medicine Research, Children's National Health System, Washington, DC
| | - Nan Chen
- Department of Nephrology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China; and
| | - Xiaoxia Pan
- Department of Nephrology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China; and
| | - Cuili Yi
- Department of Pediatrics, Fuzhou Dongfang Hospital, Fujian, People's Republic of China
| | - Xiaohua Ding
- Department of Pediatrics, Fuzhou Dongfang Hospital, Fujian, People's Republic of China
| | - Si Wang
- Department of Pediatrics, Fuzhou Dongfang Hospital, Fujian, People's Republic of China
| | - Ping Wang
- Department of Pediatrics, Fuzhou Dongfang Hospital, Fujian, People's Republic of China
| | - Xiaojing Nie
- Department of Pediatrics, Fuzhou Dongfang Hospital, Fujian, People's Republic of China.,Department of Pediatrics, Affiliated Dongfang Hospital, Xiamen University, Fujian, People's Republic of China.,Department of Pediatrics, Fuzhou Clinical Medical College, Fujian Medical University, Fujian, People's Republic of China
| | - Jun Huang
- Department of Pediatrics, Fuzhou Dongfang Hospital, Fujian, People's Republic of China.,Department of Pediatrics, Affiliated Dongfang Hospital, Xiamen University, Fujian, People's Republic of China.,Department of Pediatrics, Fuzhou Clinical Medical College, Fujian Medical University, Fujian, People's Republic of China
| | - Yonghui Yang
- Department of Pediatrics, Fuzhou Dongfang Hospital, Fujian, People's Republic of China.,Department of Pediatrics, Affiliated Dongfang Hospital, Xiamen University, Fujian, People's Republic of China.,Department of Pediatrics, Fuzhou Clinical Medical College, Fujian Medical University, Fujian, People's Republic of China
| | - Zihua Yu
- Department of Pediatrics, Fuzhou Dongfang Hospital, Fujian, People's Republic of China; .,Department of Pediatrics, Affiliated Dongfang Hospital, Xiamen University, Fujian, People's Republic of China.,Department of Pediatrics, Fuzhou Clinical Medical College, Fujian Medical University, Fujian, People's Republic of China
| | - Zhe Han
- Center for Genetic Medicine Research, Children's National Health System, Washington, DC; .,Department of Genomics and Precision Medicine, The George Washington University School of Medicine and Health Sciences, Washington, DC
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179
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Schulz A, Müller NV, van de Lest NA, Eisenreich A, Schmidbauer M, Barysenka A, Purfürst B, Sporbert A, Lorenzen T, Meyer AM, Herlan L, Witten A, Rühle F, Zhou W, de Heer E, Scharpfenecker M, Panáková D, Stoll M, Kreutz R. Analysis of the genomic architecture of a complex trait locus in hypertensive rat models links Tmem63c to kidney damage. eLife 2019; 8:42068. [PMID: 30900988 PMCID: PMC6478434 DOI: 10.7554/elife.42068] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Accepted: 03/20/2019] [Indexed: 12/23/2022] Open
Abstract
Unraveling the genetic susceptibility of complex diseases such as chronic kidney disease remains challenging. Here, we used inbred rat models of kidney damage associated with elevated blood pressure for the comprehensive analysis of a major albuminuria susceptibility locus detected in these models. We characterized its genomic architecture by congenic substitution mapping, targeted next-generation sequencing, and compartment-specific RNA sequencing analysis in isolated glomeruli. This led to prioritization of transmembrane protein Tmem63c as a novel potential target. Tmem63c is differentially expressed in glomeruli of allele-specific rat models during onset of albuminuria. Patients with focal segmental glomerulosclerosis exhibited specific TMEM63C loss in podocytes. Functional analysis in zebrafish revealed a role for tmem63c in mediating the glomerular filtration barrier function. Our data demonstrate that integrative analysis of the genomic architecture of a complex trait locus is a powerful tool for identification of new targets such as Tmem63c for further translational investigation. The human kidneys filter the entire volume of the blood about 300 times each day. This ability depends on specialized cells, known as podocytes, which wrap around some of the blood vessels in the kidney. These cells control which molecules leave the blood based on their size. Normally large molecules like proteins are blocked, while smaller molecules including waste products, toxins, excess water and salts pass through into the urine. If this filtration system is damaged, by high blood pressure, for example, it can lead to chronic kidney disease. A hallmark of this disease, often called CKD for short, is high levels of the protein albumin in the urine. Previous studies involving rats with high blood pressure have found several regions of the genome that contribute to high levels of albumin in the urine, including one on chromosome 6. However, this region contains several genes and it was unclear which genes affected the condition. Schulz et al. set out to narrow down the list and find specific genes that might contribute to elevated albumin in the urine of rats with high blood pressure. This search identified the gene for a protein called TMEM63c as a likely candidate. This protein spans the outer membrane of podocyte cells. Analysis of kidney biopsies showed that patients with chronic kidney disease also had low levels of this protein in their podocytes. Further experiments, this time in zebrafish, showed that reducing the activity of the gene for tmem63c led to damaged podocytes and a leakier filter in the kidneys. The results suggest that this gene plays an important role in the integrity of the kidneys filtration barrier. It is possible that faulty versions of this gene are behind some cases of chronic kidney disease. If this proves to be the case, a better understanding of the role of this gene may lead to new treatments for the condition.
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Affiliation(s)
- Angela Schulz
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany.,Institute of Clinical Pharmacology and Toxicology, Berlin Institute of Health, Berlin, Germany
| | - Nicola Victoria Müller
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany.,Institute of Clinical Pharmacology and Toxicology, Berlin Institute of Health, Berlin, Germany.,Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Electrochemical Signaling in Development and Disease, Berlin, Germany
| | - Nina Anne van de Lest
- Department of Pathology, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | - Andreas Eisenreich
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany.,Institute of Clinical Pharmacology and Toxicology, Berlin Institute of Health, Berlin, Germany
| | - Martina Schmidbauer
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany.,Institute of Clinical Pharmacology and Toxicology, Berlin Institute of Health, Berlin, Germany
| | - Andrei Barysenka
- Westfälische Wilhelms University, Genetic Epidemiology, Institute for Human Genetics, Münster, Germany
| | - Bettina Purfürst
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Core Facility Electron Microscopy, Berlin, Germany
| | - Anje Sporbert
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Advanced Light Microscopy, Berlin, Germany
| | - Theodor Lorenzen
- Institute of Clinical Pharmacology and Toxicology, Berlin Institute of Health, Berlin, Germany
| | | | - Laura Herlan
- Institute of Clinical Pharmacology and Toxicology, Berlin Institute of Health, Berlin, Germany
| | - Anika Witten
- Westfälische Wilhelms University, Genetic Epidemiology, Institute for Human Genetics, Münster, Germany
| | - Frank Rühle
- Westfälische Wilhelms University, Genetic Epidemiology, Institute for Human Genetics, Münster, Germany
| | - Weibin Zhou
- Division of Nephrology, Department of Medicine, Center for Human Disease Modeling, Duke University School of Medicine, Durham, United States
| | - Emile de Heer
- Department of Pathology, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | - Marion Scharpfenecker
- Department of Pathology, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | - Daniela Panáková
- DZHK (German Centre for Cardiovascular Research), Partner site Berlin, Berlin, Germany
| | - Monika Stoll
- Westfälische Wilhelms University, Genetic Epidemiology, Institute for Human Genetics, Münster, Germany.,Department of Biochemistry, Maastricht University, Genetic Epidemiology and Statistical Genetics, Maastricht, The Netherlands
| | - Reinhold Kreutz
- Institute of Clinical Pharmacology and Toxicology, Berlin Institute of Health, Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), Partner site Berlin, Berlin, Germany
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180
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Ben-Zvi DS, Volk T. Escort cell encapsulation of Drosophila germline cells is maintained by irre cell recognition module proteins. Biol Open 2019; 8:bio039842. [PMID: 30837217 PMCID: PMC6451344 DOI: 10.1242/bio.039842] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Accepted: 02/06/2019] [Indexed: 12/17/2022] Open
Abstract
Differentiation of germline stem cells (GSCs) in the Drosophila ovary is induced by somatic escort cells (ECs), which extend membrane protrusions encapsulating the germline cells (GCs). Germline encapsulation requires activated epidermal growth factor receptor (Egfr) signaling within the ECs, following secretion of its ligands from the GCs. We show that the conserved family of irre cell recognition module (IRM) proteins is essential for GC encapsulation by ECs, with a requirement for roughest (rst) and kin of irre (kirre) in the germline and for sticks and stones (sns) and hibris (hbs) in ECs. In the absence of IRM components in their respective cell types, EC extensions are reduced concomitantly with a decrease in Egfr signaling in these cells. Reintroducing either activated Egfr in the ECs, or overexpressing its ligand Spitz (Spi) from the germline, rescued the requirement for IRM proteins in both cell types. These experiments introduce novel essential components, the IRM proteins, into the process of inductive interactions between GCs and ECs, and imply that IRM-mediated activity is required upstream of the Egfr signaling.
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Affiliation(s)
- Doreen S Ben-Zvi
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Talila Volk
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
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181
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Song CC, Hong Q, Geng XD, Wang X, Wang SQ, Cui SY, Guo MD, Li O, Cai GY, Chen XM, Wu D. New Mutation of Coenzyme Q 10 Monooxygenase 6 Causing Podocyte Injury in a Focal Segmental Glomerulosclerosis Patient. Chin Med J (Engl) 2019; 131:2666-2675. [PMID: 30425193 PMCID: PMC6247592 DOI: 10.4103/0366-6999.245158] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Background: Focal segmental glomerulosclerosis (FSGS) is a kidney disease that is commonly associated with proteinuria and the progressive loss of renal function, which is characterized by podocyte injury and the depletion and collapse of glomerular capillary segments. The pathogenesis of FSGS has not been completely elucidated; however, recent advances in molecular genetics have provided increasing evidence that podocyte structural and functional disruption is central to FSGS pathogenesis. Here, we identified a patient with FSGS and aimed to characterize the pathogenic gene and verify its mechanism. Methods: Using next-generation sequencing and Sanger sequencing, we screened the causative gene that was linked to FSGS in this study. The patient's total blood RNA was extracted to validate the messenger RNA (mRNA) expression of coenzyme Q10 monooxygenase 6 (COQ6) and validated it by immunohistochemistry. COQ6 knockdown in podocytes was performed in vitro with small interfering RNA, and then, F-actin was determined using immunofluorescence staining. Cell apoptosis was evaluated by flow cytometry, the expression of active caspase-3 was determined by Western blot, and mitochondrial function was detected by MitoSOX. Results: Using whole-exome sequencing and Sanger sequencing, we screened a new causative gene, COQ6, NM_182480: exon1: c.G41A: p.W14X. The mRNA expression of COQ6 in the proband showed decreased. Moreover, the expression of COQ6, which was validated by immunohistochemistry, also had the same change in the proband. Finally, we focused on the COQ6 gene to clarify the mechanism of podocyte injury. Flow cytometry showed significantly increased in apoptotic podocytes, and Western blotting showed increases in active caspase-3 in si-COQ6 podocytes. Meanwhile, reactive oxygen species (ROS) levels were increased and F-actin immunofluorescence was irregularly distributed in the si-COQ6 group. Conclusions: This study reported a possible mechanism for FSGS and suggested that a new mutation in COQ6, which could cause respiratory chain defect, increase the generation of ROS, destroy the podocyte cytoskeleton, and induce apoptosis. It provides basic theoretical basis for the screening of FSGS in the future.
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Affiliation(s)
- Cheng-Cheng Song
- Department of Nephrology, Chinese People's Liberation Army General Hospital, Chinese People's Liberation Army Institute of Nephrology, State Key Laboratory of Kidney Diseases (2011DAV00088), National Clinical Research Center for Kidney Diseases, Beijing Key Laboratory of Kidney Diseases, Beijing 100853, China
| | - Quan Hong
- Department of Nephrology, Chinese People's Liberation Army General Hospital, Chinese People's Liberation Army Institute of Nephrology, State Key Laboratory of Kidney Diseases (2011DAV00088), National Clinical Research Center for Kidney Diseases, Beijing Key Laboratory of Kidney Diseases, Beijing 100853, China
| | - Xiao-Dong Geng
- Department of Nephrology, Chinese People's Liberation Army General Hospital, Chinese People's Liberation Army Institute of Nephrology, State Key Laboratory of Kidney Diseases (2011DAV00088), National Clinical Research Center for Kidney Diseases, Beijing Key Laboratory of Kidney Diseases, Beijing 100853, China
| | - Xu Wang
- Department of Nephrology, Chinese People's Liberation Army General Hospital, Chinese People's Liberation Army Institute of Nephrology, State Key Laboratory of Kidney Diseases (2011DAV00088), National Clinical Research Center for Kidney Diseases, Beijing Key Laboratory of Kidney Diseases, Beijing 100853, China
| | - Shu-Qiang Wang
- Department of Nephrology, Chinese People's Liberation Army General Hospital, Chinese People's Liberation Army Institute of Nephrology, State Key Laboratory of Kidney Diseases (2011DAV00088), National Clinical Research Center for Kidney Diseases, Beijing Key Laboratory of Kidney Diseases, Beijing 100853, China
| | - Shao-Yuan Cui
- Department of Nephrology, Chinese People's Liberation Army General Hospital, Chinese People's Liberation Army Institute of Nephrology, State Key Laboratory of Kidney Diseases (2011DAV00088), National Clinical Research Center for Kidney Diseases, Beijing Key Laboratory of Kidney Diseases, Beijing 100853, China
| | - Man-Di Guo
- Department of Nephrology, Chinese People's Liberation Army General Hospital, Chinese People's Liberation Army Institute of Nephrology, State Key Laboratory of Kidney Diseases (2011DAV00088), National Clinical Research Center for Kidney Diseases, Beijing Key Laboratory of Kidney Diseases, Beijing 100853, China
| | - Ou Li
- Department of Nephrology, Chinese People's Liberation Army General Hospital, Chinese People's Liberation Army Institute of Nephrology, State Key Laboratory of Kidney Diseases (2011DAV00088), National Clinical Research Center for Kidney Diseases, Beijing Key Laboratory of Kidney Diseases, Beijing 100853, China
| | - Guang-Yan Cai
- Department of Nephrology, Chinese People's Liberation Army General Hospital, Chinese People's Liberation Army Institute of Nephrology, State Key Laboratory of Kidney Diseases (2011DAV00088), National Clinical Research Center for Kidney Diseases, Beijing Key Laboratory of Kidney Diseases, Beijing 100853, China
| | - Xiang-Mei Chen
- Department of Nephrology, Chinese People's Liberation Army General Hospital, Chinese People's Liberation Army Institute of Nephrology, State Key Laboratory of Kidney Diseases (2011DAV00088), National Clinical Research Center for Kidney Diseases, Beijing Key Laboratory of Kidney Diseases, Beijing 100853, China
| | - Di Wu
- Department of Nephrology, Chinese People's Liberation Army General Hospital, Chinese People's Liberation Army Institute of Nephrology, State Key Laboratory of Kidney Diseases (2011DAV00088), National Clinical Research Center for Kidney Diseases, Beijing Key Laboratory of Kidney Diseases, Beijing 100853, China
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182
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Generation of pluripotent stem cell-derived mouse kidneys in Sall1-targeted anephric rats. Nat Commun 2019; 10:451. [PMID: 30723213 PMCID: PMC6363802 DOI: 10.1038/s41467-019-08394-9] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 01/08/2019] [Indexed: 12/14/2022] Open
Abstract
Regeneration of human kidneys in animal models would help combat the severe shortage of donors in transplantation therapy. Previously, we demonstrated by interspecific blastocyst complementation between mouse and rats, generation of pluripotent stem cell (PSC)-derived functional pancreas, in apancreatic Pdx1 mutant mice. We, however, were unable to obtain rat PSC-derived kidneys in anephric Sall1 mutant mice, likely due to the poor contribution of rat PSCs to the mouse metanephric mesenchyme, a nephron progenitor. Here, conversely, we show that mouse PSCs can efficiently differentiate into the metanephric mesenchyme in rat, allowing the generation of mouse PSC-derived kidney in anephric Sall1 mutant rat. Glomerular epithelium and renal tubules in the kidneys are entirely composed of mouse PSC-derived cells expressing key functional markers. Importantly, the ureter-bladder junction is normally formed. These data provide proof-of-principle for interspecific blastocyst complementation as a viable approach for kidney generation.
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183
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Hiratsuka K, Monkawa T, Akiyama T, Nakatake Y, Oda M, Goparaju SK, Kimura H, Chikazawa-Nohtomi N, Sato S, Ishiguro K, Yamaguchi S, Suzuki S, Morizane R, Ko SBH, Itoh H, Ko MSH. Induction of human pluripotent stem cells into kidney tissues by synthetic mRNAs encoding transcription factors. Sci Rep 2019; 9:913. [PMID: 30696889 PMCID: PMC6351687 DOI: 10.1038/s41598-018-37485-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 12/05/2018] [Indexed: 01/10/2023] Open
Abstract
The derivation of kidney tissues from human pluripotent stem cells (hPSCs) and its application for replacement therapy in end-stage renal disease have been widely discussed. Here we report that consecutive transfections of two sets of synthetic mRNAs encoding transcription factors can induce rapid and efficient differentiation of hPSCs into kidney tissues, termed induced nephron-like organoids (iNephLOs). The first set - FIGLA, PITX2, ASCL1 and TFAP2C, differentiated hPSCs into SIX2+SALL1+ nephron progenitor cells with 92% efficiency within 2 days. Subsequently, the second set - HNF1A, GATA3, GATA1 and EMX2, differentiated these cells into PAX8+LHX1+ pretubular aggregates in another 2 days. Further culture in both 2-dimensional and 3-dimensional conditions produced iNephLOs containing cells characterized as podocytes, proximal tubules, and distal tubules in an additional 10 days. Global gene expression profiles showed similarities between iNephLOs and the human adult kidney, suggesting possible uses of iNephLOs as in vitro models for kidneys.
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Affiliation(s)
- Ken Hiratsuka
- Department of Systems Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
- Department of Nephrology, Endocrinology, and Metabolism, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Toshiaki Monkawa
- Department of Nephrology, Endocrinology, and Metabolism, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
- Medical Education Center, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Tomohiko Akiyama
- Department of Systems Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Yuhki Nakatake
- Department of Systems Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Mayumi Oda
- Department of Systems Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Sravan Kumar Goparaju
- Department of Systems Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Hiromi Kimura
- Department of Systems Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Nana Chikazawa-Nohtomi
- Department of Systems Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Saeko Sato
- Department of Systems Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Keiichiro Ishiguro
- Department of Systems Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
- Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Chuo-ku, Kumamoto, 860-0811, Japan
| | - Shintaro Yamaguchi
- Department of Nephrology, Endocrinology, and Metabolism, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Sayuri Suzuki
- Department of Nephrology, Endocrinology, and Metabolism, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Ryuji Morizane
- Department of Nephrology, Endocrinology, and Metabolism, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
- Renal Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
- Harvard Stem Cell Institute, Cambridge, Massachusetts, USA
| | - Shigeru B H Ko
- Department of Systems Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Hiroshi Itoh
- Department of Nephrology, Endocrinology, and Metabolism, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Minoru S H Ko
- Department of Systems Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan.
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184
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Yao T, Udwan K, John R, Rana A, Haghighi A, Xu L, Hack S, Reich HN, Hladunewich MA, Cattran DC, Paterson AD, Pei Y, Barua M. Integration of Genetic Testing and Pathology for the Diagnosis of Adults with FSGS. Clin J Am Soc Nephrol 2019; 14:213-223. [PMID: 30647093 PMCID: PMC6390925 DOI: 10.2215/cjn.08750718] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 11/27/2018] [Indexed: 12/15/2022]
Abstract
BACKGROUND AND OBJECTIVES FSGS and nephrotic syndrome studies have shown that single gene causes are more likely to be found in pediatric cases than adults. Consequently, many studies have examined limited gene panels in largely pediatric cohorts. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Whole-exome sequencing was performed in adults with FSGS diagnosed between 1976 and 2017 in the Toronto GN Registry. An expanded panel of 109 genes linked to FSGS, glomerular basement membrane abnormalities, as well as causes of pediatric ESKD including congenital abnormalities of the kidney and urinary tract (CAKUT) and nephronophthisis, were examined. RESULTS The cohort was composed of 193 individuals from 179 families. Nearly half (49%) developed ESKD at a mean age of 47±17 years. The genetic diagnostic rate was 11%. Of definitely pathogenic variants, 55% were in COL4A (A3/A4/A5), 40% were in podocyte genes, and 5% were in CAKUT genes. Many, but not all individuals with COL4A definitely pathogenic variants had some evidence of glomerular basement membrane abnormalities. The estimated mean survival/age of kidney failure for individuals with COL4A definitely pathogenic variants was 58 years (95% confidence interval, 49 to 69), far later than what has been reported in the literature. Likely pathogenic variants were identified in an additional 9% of the cohort, with most in COL4A. Correlation with glomerular basement membrane morphology suggested a causal role for at least some of these likely pathogenic variants. CONCLUSIONS Even with an expanded gene panel, we find that COL4A disorders are the leading monogenic cause in adults diagnosed with FSGS. PODCAST This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2019_01_15_CJASNPodcast_19_02_.mp3.
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Affiliation(s)
- Tony Yao
- Division of Nephrology and.,Toronto General Hospital Research Institute, Toronto General Hospital, Toronto, Canada
| | - Khalil Udwan
- Division of Nephrology and.,Toronto General Hospital Research Institute, Toronto General Hospital, Toronto, Canada
| | - Rohan John
- Department of Pathology, University Health Network, Toronto, Canada
| | - Akanchaya Rana
- Division of Nephrology and.,Toronto General Hospital Research Institute, Toronto General Hospital, Toronto, Canada.,Institute of Medical Sciences
| | | | | | - Saidah Hack
- Division of Nephrology and.,Toronto General Hospital Research Institute, Toronto General Hospital, Toronto, Canada
| | - Heather N Reich
- Division of Nephrology and.,Toronto General Hospital Research Institute, Toronto General Hospital, Toronto, Canada.,Institute of Medical Sciences.,Department of Medicine, and
| | | | - Daniel C Cattran
- Division of Nephrology and.,Toronto General Hospital Research Institute, Toronto General Hospital, Toronto, Canada.,Institute of Medical Sciences.,Department of Medicine, and
| | - Andrew D Paterson
- Institute of Medical Sciences.,Department of Medicine, and.,Genetics and Genome Biology, Research Institute at Hospital for Sick Children, Toronto, Canada; and.,Division of Epidemiology and Biostatistics, Dalla Lana School of Public Health, Toronto, Ontario, Canada
| | - York Pei
- Division of Nephrology and.,Toronto General Hospital Research Institute, Toronto General Hospital, Toronto, Canada.,Institute of Medical Sciences.,Department of Medicine, and
| | - Moumita Barua
- Division of Nephrology and .,Toronto General Hospital Research Institute, Toronto General Hospital, Toronto, Canada.,Institute of Medical Sciences.,Department of Medicine, and
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185
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Stone H, Magella B, Bennett MR. The Search for Biomarkers to Aid in Diagnosis, Differentiation, and Prognosis of Childhood Idiopathic Nephrotic Syndrome. Front Pediatr 2019; 7:404. [PMID: 31681707 PMCID: PMC6805718 DOI: 10.3389/fped.2019.00404] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 09/18/2019] [Indexed: 12/13/2022] Open
Abstract
Identification of genes associated with childhood-onset nephrotic syndrome has significantly advanced our understanding of the pathogenesis of this complex disease over the past two decades, however the precise etiology in many cases remains unclear. At this time, we still rely on invasive kidney biopsy to determine the underlying cause of nephrotic syndrome in adults. In children, response to steroid therapy has been shown to be the best indicator of prognosis, and therefore all children are treated initially with corticosteroids. Because this strategy exposes a large number of children to the toxicities of steroids without providing any benefit, many researchers have sought to find a marker that could predict a patient's response to steroids at the time of diagnosis. Additionally, the identification of such a marker could provide prognostic information about a patient's response to medications, progression to end stage renal disease, and risk of disease recurrence following transplantation. Major advances have been made in understanding how genetic biomarkers can be used to predict a patient's response to therapies and disease course, especially after transplantation. Research attempting to identify urine- and serum-based biomarkers which could be used for the diagnosis, differentiation, and prognosis of nephrotic syndrome has become an area of emphasis. In this review, we explore the most exciting biomarkers and their potential clinical applications.
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Affiliation(s)
- Hillarey Stone
- Division of Nephrology and Hypertension, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Bliss Magella
- Division of Nephrology and Hypertension, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Michael R Bennett
- Division of Nephrology and Hypertension, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
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186
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Genetic testing in steroid-resistant nephrotic syndrome: why, who, when and how? Pediatr Nephrol 2019; 34:195-210. [PMID: 29181713 PMCID: PMC6311200 DOI: 10.1007/s00467-017-3838-6] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 10/24/2017] [Accepted: 10/25/2017] [Indexed: 12/23/2022]
Abstract
Steroid-resistant nephrotic syndrome (SRNS) is a common cause of chronic kidney disease in childhood and has a significant risk of rapid progression to end-stage renal disease. The identification of over 50 monogenic causes of SRNS has revealed dysfunction in podocyte-associated proteins in the pathogenesis of proteinuria, highlighting their essential role in glomerular function. Recent technological advances in high-throughput sequencing have enabled indication-driven genetic panel testing for patients with SRNS. The availability of genetic testing, combined with the significant phenotypic variability of monogenic SRNS, poses unique challenges for clinicians when directing genetic testing. This highlights the need for clear clinical guidelines that provide a systematic approach for mutational screening in SRNS. The likelihood of identifying a causative mutation is inversely related to age at disease onset and is increased with a positive family history or the presence of extra-renal manifestations. An unequivocal molecular diagnosis could allow for a personalised treatment approach with weaning of immunosuppressive therapy, avoidance of renal biopsy and provision of accurate, well-informed genetic counselling. Identification of novel causative mutations will continue to unravel the pathogenic mechanisms of glomerular disease and provide new insights into podocyte biology and glomerular function.
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187
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Abstract
Zusammenfassung
Das steroid-resistente nephrotische Syndrom (SRNS) mit dem histomorphologischen Korrelat der fokal-segmentalen Glomerulosklerose (FSGS) stellt eine bedeutende Ursache für eine terminale Niereninsuffizienz im Kindesalter, aber auch bei erwachsenen Patienten dar. Das Erkrankungsspektrum zeichnet sich durch eine große genetische Heterogenität aus, wobei auch nicht genetische Ursachen bei der FSGS beobachtet werden. Die genetische Grundlage des SRNS/FSGS-Komplexes ist v. a. für ältere Kinder/Jugendliche und Erwachsene bisher noch unzureichend verstanden. Die eindeutige Abgrenzung genetischer SRNS/FSGS-Ursachen ist unerlässlich, da sich bereits heute hieraus eine Vielzahl an klinischen Implikationen ergeben. Die Identifikation unbekannter Erkrankungsallele oder Erkrankungsgene kann zudem Erkenntnisse bringen, die ein gänzlich neues Verständnis der Pathomechanismen ermöglichen. Durch umfassende genetische Untersuchungen besteht die Möglichkeit, die ungelöste genetische Basis der Rekurrenz der FSGS-Erkrankung bei bislang Varianten-negativen Patienten zu finden.
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Affiliation(s)
- Julia Hoefele
- Aff1 Institut für Humangenetik Klinikum rechts der Isar, Technische Universität München Trogerstr. 32 81675 München Deutschland
| | - Bodo B. Beck
- Aff2 0000 0000 8852 305X grid.411097.a Institut für Humangenetik Uniklinik Köln Kerpener Str. 34 50937 Köln Deutschland
| | - Lutz T. Weber
- Aff3 0000 0000 8852 305X grid.411097.a Klinik und Poliklinik für Kinder- und Jugendmedizin Uniklinik Köln Kerpener Str. 62 50937 Köln Deutschland
| | - Paul Brinkkötter
- Aff4 0000 0000 8852 305X grid.411097.a Klinik II für Innere Medizin Uniklinik Köln Kerpener Str. 62 50937 Köln Deutschland
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188
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Zhai S, Zhao L, Zhang Y, Ma Q. Interleukin-7 stimulation inhibits nephrin activation and induces podocyte injury. Biochem Biophys Res Commun 2018; 507:100-105. [PMID: 30454893 DOI: 10.1016/j.bbrc.2018.10.173] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 10/28/2018] [Indexed: 12/26/2022]
Abstract
The glomerular podocytes control filtration barrier permeability in the kidney, and their disturbance underlies the pathogenesis of idiopathic nephrotic syndrome (INS), a kidney disease that predominantly occurs in children. In this study, we found that the interleukin-7 receptor (IL-7R) was induced in the glomeruli of adriamycin (ADR)-induced mouse nephropathy, a rodent model of nephrotic syndrome. In addition, IL-7R was also induced by ADR in mouse podocytes cultured in vitro. Functionally, we discovered that IL-7R activation through the stimulation of recombinant IL-7 induced apoptosis of podocytes, and moreover, IL-7 stimulation inhibited nephrin activation and caused actin cytoskeleton disorganization, indicating that IL-7 stimulation induces podocyte injury. Furthermore, IL-7 stimulation impaired the filtration barrier function of podocyte monolayer. Together, these results identify IL-7 and its receptor IL-7R as potential regulators of podocyte function, which might offer a novel therapeutic target in the treatment of INS.
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Affiliation(s)
- Shubo Zhai
- Department of Pediatric Nephropathy, The First Hospital of Jilin University, China
| | - Lengyue Zhao
- Department of Pediatric Nephropathy, The First Hospital of Jilin University, China
| | - Yan Zhang
- Department of Pediatric Nephropathy, The First Hospital of Jilin University, China
| | - Qingshan Ma
- Department of Pediatric Nephropathy, The First Hospital of Jilin University, China.
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189
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Artelt N, Siegerist F, Ritter AM, Grisk O, Schlüter R, Endlich K, Endlich N. Comparative Analysis of Podocyte Foot Process Morphology in Three Species by 3D Super-Resolution Microscopy. Front Med (Lausanne) 2018; 5:292. [PMID: 30425988 PMCID: PMC6218959 DOI: 10.3389/fmed.2018.00292] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 09/25/2018] [Indexed: 12/12/2022] Open
Abstract
Since the size selectivity of the filtration barrier and kidney function are highly dependent on podocyte foot process morphology, visualization of foot processes is important. However, the size of foot processes is below the optical resolution of light microscopy. Therefore, electron microcopy has been indispensable to detect changes in foot process morphology so far, but it is a sophisticated and time-consuming technique. Recently, our group has shown that 3D structured illumination microscopy (3D-SIM), a super-resolution microscopy (SRM) technique, can visualize individual foot processes in human biopsies. Moreover, we have developed a software-based approach to directly quantify the structure of podocyte foot processes named Podocyte Exact Morphology Measurement Procedure (PEMP). As shown in patients suffering from minimal change disease (MCD), PEMP allows the quantification of changes of the foot process morphology by measuring the filtration slit density (FSD). Since rodents are frequently used in basic research, we have applied PEMP to quantify foot processes of mice and rats. Comparative analysis of nephrin-stained kidneys from humans, rats, and mice showed significant differences of the FSD. The highest FSD was measured in mice (3.83 ± 0.37 μm−1; mean ± SD) followed by rats (3.36 ± 0.42 μm−1) and humans (3.11 ± 0.26 μm−1). To demonstrate that PEMP can be used to determine foot process morphology also in affected animals, we measured the FSD in palladin-knockout mice on a 129S1 genetic background compared to wild-type littermates. Taken together, we established a method for the quick and exact quantification of podocyte foot process morphology which can be applied to diagnosis and basic research.
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Affiliation(s)
- Nadine Artelt
- Institute for Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Florian Siegerist
- Institute for Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Alina M Ritter
- Institute for Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Olaf Grisk
- Institute for Physiology, University Medicine Greifswald, Karlsburg, Germany
| | - Rabea Schlüter
- Imaging Center of the Department of Biology, University of Greifswald, Greifswald, Germany
| | - Karlhans Endlich
- Institute for Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Nicole Endlich
- Institute for Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
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190
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Amplification of the Melanocortin-1 Receptor in Nephrotic Syndrome Identifies a Target for Podocyte Cytoskeleton Stabilization. Sci Rep 2018; 8:15731. [PMID: 30356069 PMCID: PMC6200758 DOI: 10.1038/s41598-018-34004-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 10/05/2018] [Indexed: 12/21/2022] Open
Abstract
The melanocortin-1 receptor (MC1R) in podocytes has been suggested as the mediator of the ACTH renoprotective effect in patients with nephrotic syndrome with the mechanism of action beeing stabilization of the podocyte actin cytoskeleton. To understand how melanocortin receptors are regulated in nephrotic syndrome and how they are involved in restoration of filtration barrier function, melanocortin receptor expression was evaluated in patients and a rat model of nephrotic syndrome in combination with cell culture analysis. Phosphoproteomics was applied and identified MC1R pathways confirmed using biochemical analysis. We found that glomerular MC1R expression was increased in nephrotic syndrome, both in humans and in a rat model. A MC1R agonist protected podocytes from protamine sulfate induced stress fiber loss with the top ranked phoshoproteomic MC1R activated pathway beeing actin cytoskeleton signaling. Actin stabilization through the MC1R consisted of ERK1/2 dependent phosphorylation and inactivation of EGFR signaling with stabilization of synaptopodin and stressfibers in podocytes. These results further explain how patients with nephrotic syndrome show responsiveness to MC1R receptor activation by decreasing EGFR signaling and as a consequence restore filtration barrier function by stabilizing the podocyte actin cytoskeleton.
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191
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Korolj A, Laschinger C, James C, Hu E, Velikonja C, Smith N, Gu I, Ahadian S, Willette R, Radisic M, Zhang B. Curvature facilitates podocyte culture in a biomimetic platform. LAB ON A CHIP 2018; 18:3112-3128. [PMID: 30264844 DOI: 10.1039/c8lc00495a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Most kidney diseases begin with abnormalities in glomerular podocytes, motivating the need for podocyte models to study pathophysiological mechanisms and new treatment options. However, podocytes cultured in vitro face a limited ability to maintain appreciable extents of differentiation hallmarks, raising concerns over the relevance of study results. Many key properties such as nephrin expression and morphology reach plateaus that are far from the in vivo levels. Here, we demonstrate that a biomimetic topography, consisting of microhemispheres arrayed over the cell culture substrate, promotes podocyte differentiation in vitro. We define new methods for fabricating microscale curvature on various substrates, including a thin porous membrane. By growing podocytes on our topographic substrates, we found that these biophysical cues augmented nephrin gene expression, supported full-size nephrin protein expression, encouraged structural arrangement of F-actin and nephrin within the cell, and promoted process formation and even interdigitation compared to the flat substrates. Furthermore, the topography facilitated nephrin localization on curved structures while nuclei lay in the valleys between them. The improved differentiation was also evidenced by tracking barrier function to albumin over time using our custom topomembranes. Overall, our work presents accessible methods for incorporating microcurvature on various common substrates, and demonstrates the importance of biophysical stimulation in supporting higher-fidelity podocyte cultivation in vitro.
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Affiliation(s)
- Anastasia Korolj
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Canada.
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192
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Hashmi JA, Safar RA, Afzal S, Albalawi AM, Abdu-Samad F, Iqbal Z, Basit S. Whole exome sequencing identification of a novel insertion mutation in the phospholipase C ε‑1 gene in a family with steroid resistant inherited nephrotic syndrome. Mol Med Rep 2018; 18:5095-5100. [PMID: 30280192 DOI: 10.3892/mmr.2018.9528] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Accepted: 03/27/2018] [Indexed: 11/05/2022] Open
Abstract
Nephrotic syndrome (NS) represents a heterogeneous group of kidney disorders characterized by excessive proteinuria, hypoalbuminemia and edema. Defects in the filtration barrier of the glomeruli results in the development of NS. The genetic cause of NS remains to be fully elucidated. However, previous studies based on positional cloning of genes mutated in NS have provided limited insight into the pathogenesis of this disease. Mutations in phospholipase C ε‑1 (PLCE1) have been reported as a cause of early onset NS characterized by histology of diffuse mesangial sclerosis. In the present study, the underlying cause of NS in a consanguineous family was identified. Clinical and molecular aspects of a consanguineous Saudi family comprised of five individuals with steroid resistant NS were examined. Seven healthy individuals from the same family were also studied. Whole exome sequencing (WES) was performed to detect the genetic defect underlying NS. WES identified a homozygous novel insertion mutation (c.6272_6273insT) in the PLCE1 gene. Pedigree and segregation analysis confirmed an autosomal recessive inheritance pattern. This mutation may result in a bi‑allelic loss of the C‑terminal Ras‑associating domain in PLCE1 that results in NS. The present study expanded the mutational spectrum of PLCE1 in NS. In addition, the present study provided further evidence that supports the important involvement of PLCE1 in the physiological function of the glomerular filtration barrier.
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Affiliation(s)
- Jamil Amjad Hashmi
- Center for Genetics and Inherited Diseases, Taibah University, Medina 42318, Kingdom of Saudi Arabia
| | - Ramziah Ahmed Safar
- Department of Nephrology, Madinah Maternity and Children Hospital, Medina 42319, Kingdom of Saudi Arabia
| | - Sibtain Afzal
- Prince Naif Centre for Immunology Research, College of Medicine, King Khalid University Hospital, King Saud University, Riyadh 12372, Kingdom of Saudi Arabia
| | - Alia M Albalawi
- Center for Genetics and Inherited Diseases, Taibah University, Medina 42318, Kingdom of Saudi Arabia
| | - Feroz Abdu-Samad
- Center for Genetics and Inherited Diseases, Taibah University, Medina 42318, Kingdom of Saudi Arabia
| | - Zafar Iqbal
- College of Applied Medical Sciences, National Guard Health Affairs, Al‑Ahsa 36428, Kingdom of Saudi Arabia
| | - Sulman Basit
- Center for Genetics and Inherited Diseases, Taibah University, Medina 42318, Kingdom of Saudi Arabia
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193
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Cooper CJ, Dutta NT, Martin CE, Piscione TD, Thorner PS, Jones N. Characterization of a novel disease-associated mutation within NPHS1 and its effects on nephrin phosphorylation and signaling. PLoS One 2018; 13:e0203905. [PMID: 30212551 PMCID: PMC6136785 DOI: 10.1371/journal.pone.0203905] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 08/29/2018] [Indexed: 12/22/2022] Open
Abstract
Mutations in the transmembrane protein nephrin (encoded by NPHS1) underlie nearly half of all cases of congenital nephrotic syndrome (CNS), which is caused by aberrations in the blood filtering function of glomerular podocytes. Nephrin directly contributes to the structure of the filtration barrier, and it also serves as a signaling scaffold in podocytes, undergoing tyrosine phosphorylation on its cytoplasmic tail to recruit intracellular effector proteins. Nephrin phosphorylation is lost in several human and experimental models of glomerular disease, and genetic studies have confirmed its importance in maintenance of the filtration barrier. To date, however, the effect of CNS-associated NPHS1 variants on nephrin phosphorylation remains to be determined, which hampers genotype-phenotype correlations. Here, we have characterized a novel nephrin sequence variant, A419T, which is expressed along with C623F in a patient presenting with CNS. Nephrin localization is altered in kidney biopsies, and we further demonstrate reduced surface expression and ER retention of A419T and C623F in cultured cells. Moreover, we show that both mutations impair nephrin tyrosine phosphorylation, and they exert dominant negative effects on wildtype nephrin signaling. Our findings thus reveal that missense mutations in the nephrin extracellular region can impact nephrin signaling, and they uncover a potential pathomechanism to explain the spectrum of clinical severity seen with mild NPHS1 mutations.
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Affiliation(s)
- C. James Cooper
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Nikkita T. Dutta
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Claire E. Martin
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Tino D. Piscione
- Division of Nephrology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Paul S. Thorner
- Department of Pathology and Laboratory Medicine, The Hospital for Sick Children and University of Toronto, Toronto, ON, Canada
| | - Nina Jones
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
- * E-mail:
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194
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Yu SMW, Nissaisorakarn P, Husain I, Jim B. Proteinuric Kidney Diseases: A Podocyte's Slit Diaphragm and Cytoskeleton Approach. Front Med (Lausanne) 2018; 5:221. [PMID: 30255020 PMCID: PMC6141722 DOI: 10.3389/fmed.2018.00221] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 07/18/2018] [Indexed: 01/19/2023] Open
Abstract
Proteinuric kidney diseases are a group of disorders with diverse pathological mechanisms associated with significant losses of protein in the urine. The glomerular filtration barrier (GFB), comprised of the three important layers, the fenestrated glomerular endothelium, the glomerular basement membrane (GBM), and the podocyte, dictates that disruption of any one of these structures should lead to proteinuric disease. Podocytes, in particular, have long been considered as the final gatekeeper of the GFB. This specialized visceral epithelial cell contains a complex framework of cytoskeletons forming foot processes and mediate important cell signaling to maintain podocyte health. In this review, we will focus on slit diaphragm proteins such as nephrin, podocin, TRPC6/5, as well as cytoskeletal proteins Rho/small GTPases and synaptopodin and their respective roles in participating in the pathogenesis of proteinuric kidney diseases. Furthermore, we will summarize the potential therapeutic options targeting the podocyte to treat this group of kidney diseases.
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Affiliation(s)
- Samuel Mon-Wei Yu
- Department of Medicine, Jacobi Medical Center, Bronx, NY, United States
| | | | - Irma Husain
- Department of Medicine, James J. Peters VA Medical Center, Bronx, NY, United States
| | - Belinda Jim
- Department of Medicine, Jacobi Medical Center, Bronx, NY, United States.,Renal Division, Jacobi Medical Center, Bronx, NY, United States
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195
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Weng Z, Shang Y, Ji Z, Ye F, Lin L, Zhang R, Zhu J. Structural Basis of Highly Specific Interaction between Nephrin and MAGI1 in Slit Diaphragm Assembly and Signaling. J Am Soc Nephrol 2018; 29:2362-2371. [PMID: 30006415 PMCID: PMC6115659 DOI: 10.1681/asn.2017121275] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 06/19/2018] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND The slit diaphragm is a specialized adhesion junction between opposing podocytes, establishing the final filtration barrier that prevents passage of proteins from the capillary lumen into the urinary space. Nephrin, the key structural and signaling adhesion molecule expressed in the slit diaphragm, contains an evolutionally conserved, atypical PDZ-binding motif (PBM) reported to bind to a variety of proteins in the slit diaphragm. Several mutations in NPHS1 (the gene encoding nephrin) that result in nephrin lacking an intact PBM are associated with glomerular diseases. However, the molecular basis of nephrin-PBM-mediated protein complexes is still unclear. METHODS Using a combination of biochemic, biophysic, and cell biologic approaches, we systematically investigated the interactions between nephrin-PBM and PDZ domain-containing proteins in the slit diaphragm. RESULTS We found that nephrin-PBM specifically binds to one member of the membrane-associated guanylate kinase family of scaffolding proteins, MAGI1, but not to another, MAGI2. The complex structure of MAGI1-PDZ3/nephrin-PBM reveals that the Gly at the -3 position of nephrin-PBM is the determining feature for MAGI1-PDZ3 recognition, which sharply contrasts with the typical PDZ/PBM binding mode. A single gain-of-function mutation within MAGI2 enabled nephrin-PBM binding. In addition, using our structural analysis, we developed a highly efficient inhibitory peptide capable of specifically blocking the nephrin/MAGI1 interaction. CONCLUSIONS MAGI1 interacts with nephrin-PBM with exquisite specificity. A newly developed, potent inhibitory peptide that blocks this interaction may be useful for future functional investigations in vivo. Our findings also provide possible explanations for the diseases caused by NPHS1 mutations.
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Affiliation(s)
- Zhuangfeng Weng
- State Key Laboratory of Molecular Biology, Shanghai Science Research Center, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China;,School of Life Science and Technology, ShanghaiTech University, Shanghai, China; and
| | - Yuan Shang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, and
| | - Zeyang Ji
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, and
| | - Fei Ye
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, and,Center of Systems Biology and Human Health, Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - Lin Lin
- State Key Laboratory of Molecular Biology, Shanghai Science Research Center, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Rongguang Zhang
- State Key Laboratory of Molecular Biology, Shanghai Science Research Center, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China;,School of Life Science and Technology, ShanghaiTech University, Shanghai, China; and
| | - Jinwei Zhu
- State Key Laboratory of Molecular Biology, Shanghai Science Research Center, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
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196
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AL-Ghamdi MA, Huwait EA, Kumosani TA, Qari M, Moselhy SS, Kumosani AT. Serum proteins C and S levels as early biomarkers for kidney dysfunction in hemophilic patients. Afr Health Sci 2018; 18:681-688. [PMID: 30603001 PMCID: PMC6307028 DOI: 10.4314/ahs.v18i3.26] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Hemophilia is an inherited genetic disease characterized by the inability to coagulate blood after injury. The rationale of the current study was to evaluate serum proteins S and C and correlate to kidney function test in hemophilic patients for early diagnosis of abnormality in renal function. SUBJECTS AND METHODS This study was conducted on 80 males subjects divided into four groups. Group I: Control: Healthy subjects. Group II: Renal dysfunction (serum Creatinine >2mg/dl): Group III: Hemophilic patients. Group IV: Hemophilic patients with renal disorder. Serum urea, creatinine, sodium, potassium, protein C and protein S level were determined. RESUTS Protein C and S levels showed a significant decrease in hemophilic/and with renal dysfunction (P < 0.001, p<0.001). The level of plasma protein C and S levels were positively correlated with increased urinary albumin (P < 0.01). Urinary albumin was increased about 15 folds in hemophilic patients with renal dysfunction and nephrotic patients as compared with the control group. The cut-off value in 90% patients at the hemophilic patients with renal dysfunction 70%. Positive correlations were observed between urinary albumin (r=0.66), and creatinine (r=0.73). CONCLUSION These biomarkers showed good predictive values with regard to ROC-AUC (0.41 and 0.75 for Proteins C and S, respectively).
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Affiliation(s)
- Maryam A AL-Ghamdi
- Biochemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
| | - Etimad A Huwait
- Biochemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
- Experimental Biochemistry Unit, King Fahad Medical Research center (KFMRC), Jeddah, Kingdom of Saudi Arabia
| | - Taha A Kumosani
- Biochemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
- Experimental Biochemistry Unit, King Fahad Medical Research center (KFMRC), Jeddah, Kingdom of Saudi Arabia
- Production of bio products for industrial applications research Group, KAU
| | - M Qari
- Hematology Department, Faculty of Medical Science, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
| | - Said S Moselhy
- Biochemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
- Experimental Biochemistry Unit, King Fahad Medical Research center (KFMRC), Jeddah, Kingdom of Saudi Arabia
- Bioactive Natural Products Research Group, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
- Biochemistry Department, Faculty of Science, Ain Shams University, Cairo, Egypt
| | - Afnan T Kumosani
- Department of Pathology and Laboratory Medicine, Blood Bank Transfusion Medicine, King Abdulaziz Medical City, Jeddah, National Guards, Jeddah, 21423
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197
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Tanigawa S, Islam M, Sharmin S, Naganuma H, Yoshimura Y, Haque F, Era T, Nakazato H, Nakanishi K, Sakuma T, Yamamoto T, Kurihara H, Taguchi A, Nishinakamura R. Organoids from Nephrotic Disease-Derived iPSCs Identify Impaired NEPHRIN Localization and Slit Diaphragm Formation in Kidney Podocytes. Stem Cell Reports 2018; 11:727-740. [PMID: 30174315 PMCID: PMC6135868 DOI: 10.1016/j.stemcr.2018.08.003] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/02/2018] [Accepted: 08/03/2018] [Indexed: 12/19/2022] Open
Abstract
Mutations in the NPHS1 gene, which encodes NEPHRIN, cause congenital nephrotic syndrome, resulting from impaired slit diaphragm (SD) formation in glomerular podocytes. However, methods for SD reconstitution have been unavailable, thereby limiting studies in the field. In the present study, we established human induced pluripotent stem cells (iPSCs) from a patient with an NPHS1 missense mutation, and reproduced the SD formation process using iPSC-derived kidney organoids. The mutant NEPHRIN failed to become localized on the cell surface for pre-SD domain formation in the induced podocytes. Upon transplantation, the mutant podocytes developed foot processes, but exhibited impaired SD formation. Genetic correction of the single amino acid mutation restored NEPHRIN localization and phosphorylation, colocalization of other SD-associated proteins, and SD formation. Thus, these kidney organoids from patient-derived iPSCs identified SD abnormalities in the podocytes at the initial phase of congenital nephrotic disease. iPSCs are established from a patient with a missense NPHS1 mutation The induced podocytes exhibit impaired NEPHRIN localization The slit diaphragm is lacking in the mutant podocytes Genetic correction of the point mutation restores the phenotypes
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Affiliation(s)
- Shunsuke Tanigawa
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
| | - Mazharul Islam
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
| | - Sazia Sharmin
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
| | - Hidekazu Naganuma
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan; Department of Urology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Yasuhiro Yoshimura
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
| | - Fahim Haque
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
| | - Takumi Era
- Department of Cell Modulation, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
| | - Hitoshi Nakazato
- Department of Pediatrics, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| | - Koichi Nakanishi
- Department of Child Health and Welfare (Pediatrics), Graduate School of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan
| | - Tetsushi Sakuma
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Hiroshima 739-8526, Japan
| | - Takashi Yamamoto
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Hiroshima 739-8526, Japan
| | - Hidetake Kurihara
- Department of Anatomy and Life Structure, Juntendo University School of Medicine, Tokyo 113-8421, Japan
| | - Atsuhiro Taguchi
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
| | - Ryuichi Nishinakamura
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan.
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198
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Dumas De La Roque C, Combe C, Rigothier C. [Up to date of pathophysiology mechanism of idiopathic nephrotic syndromes: Minimal change disease and focal and segmental glomerulosclerosis]. Nephrol Ther 2018; 14:501-506. [PMID: 30150079 DOI: 10.1016/j.nephro.2018.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 06/03/2018] [Indexed: 01/27/2023]
Abstract
Idiopathic nephrotic syndrome represents up to 30% of adult glomerulopathies. However, its prognosis according to remission, relapse and renal failure remains unchanged since the 80s and prediction remains difficult. Physiopathology of adult idiopathic nephrotic syndrome is complex and multifactorial, including immunologic and environmental factors and a putative permeability-circulating factor, still unknown. In this point of view, we propose to summarize actual knowledge about idiopathic minimal change disease and focal and segmental glomerulosclerosis physiopathology.
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Affiliation(s)
- Charlotte Dumas De La Roque
- Service de néphrologie transplantation et dialyse, centre hospitalier universitaire de Bordeaux, 33076 Bordeaux, France.
| | - Christian Combe
- Service de néphrologie transplantation et dialyse, centre hospitalier universitaire de Bordeaux, 33076 Bordeaux, France; Inserm U1026, université de Bordeaux, 33076 Bordeaux, France
| | - Claire Rigothier
- Service de néphrologie transplantation et dialyse, centre hospitalier universitaire de Bordeaux, 33076 Bordeaux, France; Inserm U1026, université de Bordeaux, 33076 Bordeaux, France
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199
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Empitu MA, Kadariswantiningsih IN, Aizawa M, Asanuma K. MAGI-2 and scaffold proteins in glomerulopathy. Am J Physiol Renal Physiol 2018; 315:F1336-F1344. [PMID: 30110567 DOI: 10.1152/ajprenal.00292.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
In many cells and tissues, including the glomerular filtration barrier, scaffold proteins are critical in optimizing signal transduction by enhancing structural stability and functionality of their ligands. Recently, mutations in scaffold protein membrane-associated guanylate kinase inverted 2 (MAGI-2) encoding gene were identified among the etiology of steroid-resistant nephrotic syndrome. MAGI-2 interacts with core proteins of multiple pathways, such as transforming growth factor-β signaling, planar cell polarity pathway, and Wnt/β-catenin signaling in podocyte and slit diaphragm. Through the interaction with its ligand, MAGI-2 modulates the regulation of apoptosis, cytoskeletal reorganization, and glomerular development. This review aims to summarize recent findings on the role of MAGI-2 and some other scaffold proteins, such as nephrin and synaptopodin, in the underlying mechanisms of glomerulopathy.
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Affiliation(s)
- Maulana A Empitu
- Department of Nephrology, Graduate School of Medicine, Chiba University , Chiba , Japan.,Department of Pharmacology and Therapeutics, Faculty of Medicine, Universitas Airlangga , Surabaya , Indonesia
| | - Ika N Kadariswantiningsih
- Department of Nephrology, Graduate School of Medicine, Chiba University , Chiba , Japan.,Department of Medical Microbiology, Faculty of Medicine, Universitas Airlangga , Surabaya , Indonesia
| | - Masashi Aizawa
- Department of Nephrology, Graduate School of Medicine, Chiba University , Chiba , Japan
| | - Katsuhiko Asanuma
- Department of Nephrology, Graduate School of Medicine, Chiba University , Chiba , Japan
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200
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Hermle T, Schneider R, Schapiro D, Braun DA, van der Ven AT, Warejko JK, Daga A, Widmeier E, Nakayama M, Jobst-Schwan T, Majmundar AJ, Ashraf S, Rao J, Finn LS, Tasic V, Hernandez JD, Bagga A, Jalalah SM, El Desoky S, Kari JA, Laricchia KM, Lek M, Rehm HL, MacArthur DG, Mane S, Lifton RP, Shril S, Hildebrandt F. GAPVD1 and ANKFY1 Mutations Implicate RAB5 Regulation in Nephrotic Syndrome. J Am Soc Nephrol 2018; 29:2123-2138. [PMID: 29959197 PMCID: PMC6065084 DOI: 10.1681/asn.2017121312] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 05/24/2018] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Steroid-resistant nephrotic syndrome (SRNS) is a frequent cause of CKD. The discovery of monogenic causes of SRNS has revealed specific pathogenetic pathways, but these monogenic causes do not explain all cases of SRNS. METHODS To identify novel monogenic causes of SRNS, we screened 665 patients by whole-exome sequencing. We then evaluated the in vitro functional significance of two genes and the mutations therein that we discovered through this sequencing and conducted complementary studies in podocyte-like Drosophila nephrocytes. RESULTS We identified conserved, homozygous missense mutations of GAPVD1 in two families with early-onset NS and a homozygous missense mutation of ANKFY1 in two siblings with SRNS. GAPVD1 and ANKFY1 interact with the endosomal regulator RAB5. Coimmunoprecipitation assays indicated interaction between GAPVD1 and ANKFY1 proteins, which also colocalized when expressed in HEK293T cells. Silencing either protein diminished the podocyte migration rate. Compared with wild-type GAPVD1 and ANKFY1, the mutated proteins produced upon ectopic expression of GAPVD1 or ANKFY1 bearing the patient-derived mutations exhibited altered binding affinity for active RAB5 and reduced ability to rescue the knockout-induced defect in podocyte migration. Coimmunoprecipitation assays further demonstrated a physical interaction between nephrin and GAPVD1, and immunofluorescence revealed partial colocalization of these proteins in rat glomeruli. The patient-derived GAPVD1 mutations reduced nephrin-GAPVD1 binding affinity. In Drosophila, silencing Gapvd1 impaired endocytosis and caused mistrafficking of the nephrin ortholog. CONCLUSIONS Mutations in GAPVD1 and probably in ANKFY1 are novel monogenic causes of NS. The discovery of these genes implicates RAB5 regulation in the pathogenesis of human NS.
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Affiliation(s)
- Tobias Hermle
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
- Renal Division, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ronen Schneider
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - David Schapiro
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Daniela A Braun
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Amelie T van der Ven
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Jillian K Warejko
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Ankana Daga
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Eugen Widmeier
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Makiko Nakayama
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Tilman Jobst-Schwan
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Amar J Majmundar
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Shazia Ashraf
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Jia Rao
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Laura S Finn
- Department of Pathology, Seattle Children's Hospital, University of Washington, Seattle, Washington
| | - Velibor Tasic
- Department of Pediatric Nephrology, Medical Faculty Skopje, University Children's Hospital, Skopje, Macedonia
| | - Joel D Hernandez
- Department of Pediatric Nephrology, Providence Sacred Heart Medical Center and Children's Hospital, Spokane, Washington
| | - Arvind Bagga
- Division of Nephrology, All India Institute of Medical Sciences, New Delhi, India
| | | | - Sherif El Desoky
- Pediatric Nephrology Center of Excellence and Pediatric Department, Faculty of Medicine, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
| | - Jameela A Kari
- Pediatric Nephrology Center of Excellence and Pediatric Department, Faculty of Medicine, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
| | - Kristen M Laricchia
- Broad Center for Mendelian Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Monkol Lek
- Broad Center for Mendelian Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Heidi L Rehm
- Broad Center for Mendelian Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Daniel G MacArthur
- Broad Center for Mendelian Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Shrikant Mane
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut; and
| | - Richard P Lifton
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut; and
- Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, New York
| | - Shirlee Shril
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Friedhelm Hildebrandt
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts;
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