1
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Chen J, Wang X, He Q, Yang HC, Fogo AB, Harris RC. Inhibition of transcriptional coactivator YAP Impairs the expression and function of transcription factor WT1 in diabetic podocyte injury. Kidney Int 2024; 105:1200-1211. [PMID: 38423183 DOI: 10.1016/j.kint.2024.01.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 01/12/2024] [Accepted: 01/24/2024] [Indexed: 03/02/2024]
Abstract
Podocyte injury and loss are hallmarks of diabetic nephropathy (DN). However, the molecular mechanisms underlying these phenomena remain poorly understood. YAP (Yes-associated protein) is an important transcriptional coactivator that binds with various other transcription factors, including the TEAD family members (nuclear effectors of the Hippo pathway), that regulate cell proliferation, differentiation, and apoptosis. The present study found an increase in YAP phosphorylation at S127 of YAP and a reduction of nuclear YAP localization in podocytes of diabetic mouse and human kidneys, suggesting dysregulation of YAP may play a role in diabetic podocyte injury. Tamoxifen-inducible podocyte-specific Yap gene knockout mice (YappodKO) exhibited accelerated and worsened diabetic kidney injury. YAP inactivation decreased transcription factor WT1 expression with subsequent reduction of Tead1 and other well-known targets of WT1 in diabetic podocytes. Thus, our study not only sheds light on the pathophysiological roles of the Hippo pathway in diabetic podocyte injury but may also lead to the development of new therapeutic strategies to prevent and/or treat DN by targeting the Hippo signaling pathway.
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Affiliation(s)
- Jianchun Chen
- Department of Veterans Affairs, Nashville, Tennessee, USA; Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Vanderbilt Center for Kidney Disease, Nashville, Tennessee, USA.
| | - Xiaoyong Wang
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Qian He
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Hai-Chun Yang
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Agnes B Fogo
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Raymond C Harris
- Department of Veterans Affairs, Nashville, Tennessee, USA; Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Vanderbilt Center for Kidney Disease, Nashville, Tennessee, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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2
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Li L, Long J, Mise K, Poungavrin N, Lorenzi PL, Mahmud I, Tan L, Saha PK, Kanwar YS, Chang BH, Danesh FR. The transcription factor ChREBP links mitochondrial lipidomes to mitochondrial morphology and progression of diabetic kidney disease. J Biol Chem 2023; 299:105185. [PMID: 37611830 PMCID: PMC10506103 DOI: 10.1016/j.jbc.2023.105185] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 07/27/2023] [Accepted: 08/09/2023] [Indexed: 08/25/2023] Open
Abstract
A substantial body of evidence has established the contributions of both mitochondrial dynamics and lipid metabolism to the pathogenesis of diabetic kidney disease (DKD). However, the precise interplay between these two key metabolic regulators of DKD is not fully understood. Here, we uncover a link between mitochondrial dynamics and lipid metabolism by investigating the role of carbohydrate-response element-binding protein (ChREBP), a glucose-responsive transcription factor and a master regulator of lipogenesis, in kidney podocytes. We find that inducible podocyte-specific knockdown of ChREBP in diabetic db/db mice improves key biochemical and histological features of DKD in addition to significantly reducing mitochondrial fragmentation. Because of the critical role of ChREBP in lipid metabolism, we interrogated whether and how mitochondrial lipidomes play a role in ChREBP-mediated mitochondrial fission. Our findings suggest a key role for a family of ether phospholipids in ChREBP-induced mitochondrial remodeling. We find that overexpression of glyceronephosphate O-acyltransferase, a critical enzyme in the biosynthesis of plasmalogens, reverses the protective phenotype of ChREBP deficiency on mitochondrial fragmentation. Finally, our data also points to Gnpat as a direct transcriptional target of ChREBP. Taken together, our results uncover a distinct mitochondrial lipid signature as the link between ChREBP-induced mitochondrial dynamics and progression of DKD.
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Affiliation(s)
- Li Li
- Section of Nephrology, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA; Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jianyin Long
- Section of Nephrology, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Koki Mise
- Section of Nephrology, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA; Department of Nephrology, Rheumatology, Endocrinology and Metabolism, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Naravat Poungavrin
- Department of Clinical Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Philip L Lorenzi
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Iqbal Mahmud
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Lin Tan
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Pradip K Saha
- Division of Diabetes, Endocrinology & Metabolism, Department of Medicine, Diabetes Research Center, Baylor College of Medicine, Houston, Texas, USA
| | - Yashpal S Kanwar
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Benny H Chang
- Section of Nephrology, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Farhad R Danesh
- Section of Nephrology, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA; Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA.
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3
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Li L, Long J, Mise K, Galvan DL, Overbeek PA, Tan L, Kumar SV, Chan WK, Lorenzi PL, Chang BH, Danesh FR. PGC1α is required for the renoprotective effect of lncRNA Tug1 in vivo and links Tug1 with urea cycle metabolites. Cell Rep 2021; 36:109510. [PMID: 34380028 PMCID: PMC8369494 DOI: 10.1016/j.celrep.2021.109510] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 06/08/2021] [Accepted: 07/20/2021] [Indexed: 01/14/2023] Open
Abstract
lncRNA taurine-upregulated gene 1 (Tug1) is a promising therapeutic target in the progression of diabetic nephropathy (DN), but the molecular basis of its protection remains poorly understood. Here, we generate a triple-mutant diabetic mouse model coupled with metabolomic profiling data to interrogate whether Tug1 interaction with peroxisome proliferator-activated receptor gamma coactivator 1α (PGC1α) is required for mitochondrial remodeling and progression of DN in vivo. We find that, compared with diabetic conditional deletion of Pgc1α in podocytes alone (db/db; Pgc1αPod-f/f), diabetic Pgc1α knockout combined with podocyte-specific Tug1 overexpression (db/db; TugPodTg; Pgc1αPod-f/f) reverses the protective phenotype of Tug1 overexpression, suggesting that PGC1α is required for the renoprotective effect of Tug1. Using unbiased metabolomic profiling, we find that altered urea cycle metabolites and mitochondrial arginase 2 play an important role in Tug1/PGC1α-induced mitochondrial remodeling. Our work identifies a functional role of the Tug1/PGC1α axis on mitochondrial metabolic homeostasis and urea cycle metabolites in experimental models of diabetes.
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Affiliation(s)
- Li Li
- Section of Nephrology, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Jianyin Long
- Section of Nephrology, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Koki Mise
- Section of Nephrology, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Department of Nephrology, Rheumatology, Endocrinology and Metabolism, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Daniel L Galvan
- Section of Nephrology, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Paul A Overbeek
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lin Tan
- Metabolomics Core Facility, Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Shwetha V Kumar
- Metabolomics Core Facility, Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Wai Kin Chan
- Metabolomics Core Facility, Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Phillip L Lorenzi
- Metabolomics Core Facility, Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Benny H Chang
- Section of Nephrology, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Farhad R Danesh
- Section of Nephrology, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, TX 77030, USA.
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4
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Drake KA, Fessler AR, Carroll TJ. Methods for renal lineage tracing: In vivo and beyond. Methods Cell Biol 2019; 154:121-143. [PMID: 31493814 DOI: 10.1016/bs.mcb.2019.06.002] [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] [Indexed: 02/07/2023]
Abstract
Lineage tracing has resulted in fundamental discoveries in kidney development and disease and remains a powerful technique to study mechanisms of organogenesis, homeostasis, and repair/regeneration. Following decades of research on the cellular and molecular regulation of renal organogenesis, the kidney has become one of the most well-characterized organs, resulting in exciting advancements in pluripotent stem cell differentiation, tissue bioengineering, and the potential for developing novel regenerative therapies for kidney disease. Lineage tracing, or the labeling of progeny cells arising from a single cell or group of cells, allows for spatial and temporal analyses of dynamic in vivo and in vitro processes. As lineage tracing techniques expand across disciplines of developmental biology, stem cell biology, and regenerative medicine, careful experimental design and interpretation, along with an understanding of the basic principles and technical limitations, are essential for utilizing genetically complex lineage tracing models to further understand kidney development and disease.
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Affiliation(s)
- Keri A Drake
- Division of Pediatric Nephrology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Alicia R Fessler
- Department of Internal Medicine (Nephrology), University of Texas Southwestern Medical Center, Dallas, TX, United States; Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Thomas J Carroll
- Department of Internal Medicine (Nephrology), University of Texas Southwestern Medical Center, Dallas, TX, United States; Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, United States.
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5
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Verma R, Venkatareddy M, Kalinowski A, Li T, Kukla J, Mollin A, Cara-Fuentes G, Patel SR, Garg P. Nephrin is necessary for podocyte recovery following injury in an adult mature glomerulus. PLoS One 2018; 13:e0198013. [PMID: 29924795 PMCID: PMC6010211 DOI: 10.1371/journal.pone.0198013] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 05/12/2018] [Indexed: 11/28/2022] Open
Abstract
Nephrin (Nphs1) is an adhesion protein that is expressed at the podocyte intercellular junction in the glomerulus. Nphs1 mutations in humans or deletion in animal genetic models results in a developmental failure of foot process formation. A number of studies have shown decrease in expression of nephrin in various proteinuric kidney diseases as well as in animal models of glomerular disease. Decrease in nephrin expression has been suggested to precede podocyte loss and linked to the progression of kidney disease. Whether the decrease in expression of nephrin is related to loss of podocytes or lead to podocyte detachment is unclear. To answer this central question we generated an inducible model of nephrin deletion (Nphs1Tam-Cre) in order to lower nephrin expression in healthy adult mice. Following tamoxifen-induction there was a 75% decrease in nephrin expression by 14 days. The Nphs1Tam-Cre mice had normal foot process ultrastructure and intact filtration barriers up to 4-6 weeks post-induction. Despite the loss of nephrin expression, the podocyte number and density remained unchanged during the initial period. Unexpectedly, nephrin expression, albeit at low levels persisted at the slit diaphragm up to 16-20 weeks post-tamoxifen induction. The mice became progressively proteinuric with glomerular hypertrophy and scarring reminiscent of focal and segmental glomerulosclerosis at 20 weeks. Four week-old Nphs1 knockout mice subjected to protamine sulfate model of podocyte injury demonstrated failure to recover from foot process effacement following heparin sulfate. Similarly, Nphs1 knockout mice failed to recover following nephrotoxic serum (NTS) with persistence of proteinuria and foot process effacement. Our results suggest that as in development, nephrin is necessary for maintenance of a healthy glomerular filter. In contrast to the developmental phenotype, lowering nephrin expression in a mature glomerulus resulted in a slowly progressive disease that histologically resembles FSGS a disease linked closely with podocyte depletion. Podocytes with low levels of nephrin expression are both susceptible and unable to recover following perturbation. Our results suggest that decreased nephrin expression independent of podocyte loss occurring as an early event in proteinuric kidney diseases might play a role in disease progression.
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Affiliation(s)
- Rakesh Verma
- Division of Nephrology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - Madhusudan Venkatareddy
- Division of Nephrology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - Anne Kalinowski
- Division of Nephrology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - Theodore Li
- Division of Nephrology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - Joanna Kukla
- Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | | | - Gabriel Cara-Fuentes
- Division of Pediatric Nephrology, Motts Children Hospital, Ann Arbor, Michigan, United States of America
| | - Sanjeevkumar R. Patel
- Division of Nephrology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
- Veterans Administration, VAMC, Ann Arbor, Michigan, United States of America
| | - Puneet Garg
- Division of Nephrology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
- Veterans Administration, VAMC, Ann Arbor, Michigan, United States of America
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6
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Chen L, Gao C, Zhang L, Zhang Y, Chen E, Zhang W. Highly tamoxifen-inducible principal cell-specific Cre mice with complete fidelity in cell specificity and no leakiness. Am J Physiol Renal Physiol 2018; 314:F572-F583. [PMID: 29357435 PMCID: PMC5966762 DOI: 10.1152/ajprenal.00436.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 12/11/2017] [Accepted: 12/13/2017] [Indexed: 11/22/2022] Open
Abstract
An ideal inducible system should be cell specific and have absolutely no background recombination without induction (i.e., no leakiness), a high recombination rate after induction, and complete fidelity in cell specificity (i.e., restricted recombination exclusively in cells where the driver gene is expressed). However, such an ideal mouse model remains unavailable for collecting duct research. Here, we report a mouse model that meets these criteria. In this model, a cassette expressing ERT2CreERT2 ( ECE) is inserted at the ATG of the endogenous Aqp2 locus to disrupt Aqp2 function and to express ECE under the control of the Aqp2 promoter. The resulting allele is named Aqp2ECE. There was no indication of a significant impact of disruption of a copy of Aqp2 on renal function and blood pressure control in adult Aqp2ECE/+ heterozygotes. Without tamoxifen, Aqp2ECE did not activate a Cre-dependent red fluorescence protein (RFP) reporter in adult kidneys. A single injection of tamoxifen (2 mg) to adult mice enabled Aqp2ECE to induce robust RFP expression in the whole kidney 24 h postinjection, with the highest recombination efficiency of 95% in the inner medulla. All RFP-labeled cells expressed principal cell markers (Aqp2 and Aqp3), but not intercalated cell markers (V-ATPase B1B2, and carbonic anhydrase II). Hence, Aqp2ECE confers principal cell-specific tamoxifen-inducible recombination with absolutely no leakiness, high inducibility, and complete fidelity in cell specificity, which should be an important tool for temporospatial control of target genes in the principal cells and for Aqp2+ lineage tracing in adult mice.
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Affiliation(s)
- Lihe Chen
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute , Bethesda, Maryland
| | - Chao Gao
- Department of Regenerative and Cancer Cell Biology, Albany Medical College , Albany, New York
| | - Long Zhang
- Department of Regenerative and Cancer Cell Biology, Albany Medical College , Albany, New York
| | - Ye Zhang
- Department of Regenerative and Cancer Cell Biology, Albany Medical College , Albany, New York
| | - Enuo Chen
- Department of Regenerative and Cancer Cell Biology, Albany Medical College , Albany, New York
| | - Wenzheng Zhang
- Department of Regenerative and Cancer Cell Biology, Albany Medical College , Albany, New York
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7
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Wang H, Feng Z, Xie J, Wen F, Jv M, Liang T, Li J, Wang Y, Zuo Y, Li S, Li R, Li Z, Zhang B, Liang X, Liu S, Shi W, Wang W. Podocyte-specific knockin of PTEN protects kidney from hyperglycemia. Am J Physiol Renal Physiol 2018; 314:F1096-F1107. [PMID: 29361670 DOI: 10.1152/ajprenal.00575.2017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) has proven to be downregulated in podocytes challenged with high glucose (HG), and knockout of PTEN in podocytes aggravated the progression of diabetic kidney disease (DKD). However, whether podocyte-specific knockin of PTEN protects the kidney against hyperglycemia in vivo remains unknown. The inducible podocyte-specific PTEN knockin (PPKI) mice were generated by crossing newly created transgenic loxP-stop- loxP-PTEN mice with podocin-iCreERT2 mice. Diabetes mellitus was induced in mice by intraperitoneal injection of streptozotocin at a dose of 150 mg/kg. In vitro, small interfering RNA and adenovirus interference were used to observe the role of PTEN in HG-treated podocytes. Our data demonstrated that PTEN was markedly reduced in the podocytes of patients with DKD and focal segmental glomerulosclerosis, as well as in those of db/db mice. Interestingly, podocyte-specific knockin of PTEN significantly alleviated albuminuria, mesangial matrix expansion, effacement of podocyte foot processes, and incrassation of glomerular basement membrane in diabetic PPKI mice compared with wild-type diabetic mice, whereas no alteration was observed in the level of blood glucose. The potential renal protection of overexpressed PTEN in podocytes was partly attributed with an improvement in autophagy and motility and the inhibition of apoptosis. Our results showed that podocyte-specific knockin of PTEN protected the kidney against hyperglycemia in vivo , suggesting that targeting PTEN might be a novel and promising therapeutic strategy against DKD.
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Affiliation(s)
- Huizhen Wang
- Division of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences , Guangzhou , China
| | - Ziwei Feng
- Division of Urology, Guangdong General Hospital, Guangdong Academy of Medical Sciences , Guangzhou , China
| | - Jianteng Xie
- Division of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences , Guangzhou , China
| | - Feng Wen
- Division of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences , Guangzhou , China
| | - Menglei Jv
- Division of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences , Guangzhou , China
| | - Tiantian Liang
- Division of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences , Guangzhou , China
| | - Jing Li
- Division of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences , Guangzhou , China
| | - Yanhui Wang
- Division of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences , Guangzhou , China
| | - Yangyang Zuo
- Division of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences , Guangzhou , China
| | - Sheng Li
- Division of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences , Guangzhou , China
| | - Ruizhao Li
- Division of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences , Guangzhou , China
| | - Zhilian Li
- Division of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences , Guangzhou , China
| | - Bin Zhang
- Division of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences , Guangzhou , China
| | - Xinling Liang
- Division of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences , Guangzhou , China
| | - Shuangxin Liu
- Division of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences , Guangzhou , China
| | - Wei Shi
- Division of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences , Guangzhou , China
| | - Wenjian Wang
- Division of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences , Guangzhou , China
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8
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Song K, Fu J, Song J, Herzog BH, Bergstrom K, Kondo Y, McDaniel JM, McGee S, Silasi-Mansat R, Lupu F, Chen H, Bagavant H, Xia L. Loss of mucin-type O-glycans impairs the integrity of the glomerular filtration barrier in the mouse kidney. J Biol Chem 2017; 292:16491-16497. [PMID: 28842487 DOI: 10.1074/jbc.m117.798512] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 08/14/2017] [Indexed: 12/14/2022] Open
Abstract
The kidney's filtration activity is essential for removing toxins and waste products from the body. The vascular endothelial cells of the glomerulus are fenestrated, flattened, and surrounded by podocytes, specialized cells that support glomerular endothelial cells. Mucin-type core 1-derived O-glycans (O-glycans) are highly expressed on both glomerular capillary endothelial cells and their supporting podocytes, but their biological role is unclear. Biosynthesis of core 1-derived O-glycans is catalyzed by the glycosyltransferase core 1 β1,3-galactosyltransferase (C1galt1). Here we report that neonatal or adult mice with inducible deletion of C1galt1 (iC1galt1-/-) exhibit spontaneous proteinuria and rapidly progressing glomerulosclerosis. Ultrastructural analysis of the glomerular filtration barrier components revealed that loss of O-glycans results in altered podocyte foot processes. Further analysis indicated that O-glycan is essential for the normal signaling function of podocalyxin, a podocyte foot process-associated glycoprotein. Our results reveal a new function of O-glycosylation in the integrity of the glomerular filtration barrier.
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Affiliation(s)
- Kai Song
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104.,the Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Jianxin Fu
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Jianhua Song
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Brett H Herzog
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Kirk Bergstrom
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Yuji Kondo
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - J Michael McDaniel
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Samuel McGee
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Robert Silasi-Mansat
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Florea Lupu
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Hong Chen
- the Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Harini Bagavant
- the Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Lijun Xia
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, .,the Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu, China, and.,the Department of Molecular Biology and Biochemistry, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma 73104
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9
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Yi M, Zhang L, Liu Y, Livingston MJ, Chen JK, Nahman NS, Liu F, Dong Z. Autophagy is activated to protect against podocyte injury in adriamycin-induced nephropathy. Am J Physiol Renal Physiol 2017; 313:F74-F84. [PMID: 28404589 DOI: 10.1152/ajprenal.00114.2017] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 04/04/2017] [Accepted: 04/06/2017] [Indexed: 11/22/2022] Open
Abstract
Podocytes are highly differentiated epithelial cells wrapping glomerular capillaries to form the filtration barrier in kidneys. As such, podocyte injury or dysfunction is a critical pathogenic event in glomerular disease. Autophagy plays an important role in the maintenance of the homeostasis and function of podocytes. However, it is less clear whether and how autophagy contributes to podocyte injury in glomerular disease. Here, we have examined the role of autophagy in adriamycin-induced nephropathy, a classic model of glomerular disease. We show that autophagy was induced by adriamycin in cultured podocytes in vitro and in podocytes in mice. In cultured podocytes, activation of autophagy with rapamycin led to the suppression of adriamycin-induced apoptosis, whereas inhibition of autophagy with chloroquine enhanced podocyte apoptosis during adriamycin treatment. To determine the role of autophagy in vivo, we established an inducible podocyte-specific autophagy-related gene 7 knockout mouse model (Podo-Atg7-KO). Compared with wild-type littermates, Podo-Atg7-KO mice showed higher levels of podocyte injury, glomerulopathy, and proteinuria during adriamycin treatment. Together, these observations support an important role of autophagy in protecting podocytes under the pathological conditions of glomerular disease, suggesting the therapeutic potential of autophagy induction.
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Affiliation(s)
- Mixuan Yi
- Department of Nephrology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China.,Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University and Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia; and
| | - Lei Zhang
- Department of Nephrology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China.,Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University and Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia; and
| | - Yu Liu
- Department of Nephrology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China.,Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University and Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia; and
| | - Man J Livingston
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University and Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia; and
| | - Jian-Kang Chen
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University and Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia; and
| | - N Stanley Nahman
- Department of Medicine, Medical College of Georgia at Augusta University and Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia
| | - Fuyou Liu
- Department of Nephrology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zheng Dong
- Department of Nephrology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China; .,Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University and Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia; and
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10
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Woodard LE, Cheng J, Welch RC, Williams FM, Luo W, Gewin LS, Wilson MH. Kidney-specific transposon-mediated gene transfer in vivo. Sci Rep 2017; 7:44904. [PMID: 28317878 PMCID: PMC5357952 DOI: 10.1038/srep44904] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 02/14/2017] [Indexed: 12/18/2022] Open
Abstract
Methods enabling kidney-specific gene transfer in adult mice are needed to develop new therapies for kidney disease. We attempted kidney-specific gene transfer following hydrodynamic tail vein injection using the kidney-specific podocin and gamma-glutamyl transferase promoters, but found expression primarily in the liver. In order to achieve kidney-specific transgene expression, we tested direct hydrodynamic injection of a DNA solution into the renal pelvis and found that luciferase expression was strong in the kidney and absent from extra-renal tissues. We observed heterogeneous, low-level transfection of the collecting duct, proximal tubule, distal tubule, interstitial cells, and rarely glomerular cells following injection. To assess renal injury, we performed the renal pelvis injections on uninephrectomised mice and found that their blood urea nitrogen was elevated at two days post-transfer but resolved within two weeks. Although luciferase expression quickly decreased following renal pelvis injection, the use of the piggyBac transposon system improved long-term expression. Immunosuppression with cyclophosphamide stabilised luciferase expression, suggesting immune clearance of the transfected cells occurs in immunocompetent animals. Injection of a transposon expressing erythropoietin raised the haematocrit, indicating that the developed injection technique can elicit a biologic effect in vivo. Hydrodynamic renal pelvis injection enables transposon mediated-kidney specific gene transfer in adult mice.
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Affiliation(s)
- Lauren E Woodard
- Department of Veterans Affairs, Nashville, TN 37212 USA.,Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232 USA.,Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jizhong Cheng
- Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Richard C Welch
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232 USA
| | - Felisha M Williams
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232 USA
| | - Wentian Luo
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232 USA
| | - Leslie S Gewin
- Department of Veterans Affairs, Nashville, TN 37212 USA.,Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232 USA.,Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232 USA
| | - Matthew H Wilson
- Department of Veterans Affairs, Nashville, TN 37212 USA.,Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232 USA.,Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA.,Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232 USA.,Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232 USA.,Department of Veterans Affairs, Houston, TX 77030 USA
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11
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miR-93 regulates Msk2-mediated chromatin remodelling in diabetic nephropathy. Nat Commun 2016; 7:12076. [PMID: 27350436 PMCID: PMC4931323 DOI: 10.1038/ncomms12076] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 05/26/2016] [Indexed: 01/15/2023] Open
Abstract
How the kidney responds to the metabolic cues from the environment remains a central question in kidney research. This question is particularly relevant to the pathogenesis of diabetic nephropathy (DN) in which evidence suggests that metabolic events in podocytes regulate chromatin structure. Here, we show that miR-93 is a critical metabolic/epigenetic switch in the diabetic milieu linking the metabolic state to chromatin remodelling. Mice with inducible overexpression of a miR-93 transgene exclusively in podocytes exhibit significant improvements in key features of DN. We identify miR-93 as a regulator of nucleosomal dynamics in podocytes. miR-93 has a critical role in chromatin reorganization and progression of DN by modulating its target Msk2, a histone kinase, and its substrate H3S10. These findings implicate a central role for miR-93 in high glucose-induced chromatin remodelling in the kidney, and provide evidence for a previously unrecognized role for Msk2 as a target for DN therapy. Podocyte injury is central to kidney dysfunction in diabetic nephropathy. Here the authors show that Msk2 is a target of miR-93 and this interaction mediates pathogenic chromatin remodelling in diabetic nephropathy.
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12
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Ayanga BA, Badal SS, Wang Y, Galvan DL, Chang BH, Schumacker PT, Danesh FR. Dynamin-Related Protein 1 Deficiency Improves Mitochondrial Fitness and Protects against Progression of Diabetic Nephropathy. J Am Soc Nephrol 2016; 27:2733-47. [PMID: 26825530 DOI: 10.1681/asn.2015101096] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 12/09/2015] [Indexed: 11/03/2022] Open
Abstract
Mitochondrial fission has been linked to the pathogenesis of diabetic nephropathy (DN). However, how mitochondrial fission affects progression of DN in vivo is unknown. Here, we report the effect of conditional podocyte-specific deletion of dynamin-related protein 1 (Drp1), an essential component of mitochondrial fission, on the pathogenesis and progression of DN. Inducible podocyte-specific deletion of Drp1 in diabetic mice decreased albuminuria and improved mesangial matrix expansion and podocyte morphology. Ultrastructure analysis revealed a significant increase in fragmented mitochondria in the podocytes of wild-type diabetic mice but a marked improvement in mitochondrial structure in Drp1-null podocytes of diabetic mice. When isolated from diabetic mice and cultured in high glucose, Drp1-null podocytes had more elongated mitochondria and better mitochondrial fitness associated with enhanced oxygen consumption and ATP production than wild-type podocytes. Furthermore, administration of a pharmacologic inhibitor of Drp1, Mdivi1, significantly blunted mitochondrial fission and rescued key pathologic features of DN in mice. Taken together, these results provide novel correlations between mitochondrial morphology and the progression of DN and point to Drp1 as a potential therapeutic target in DN.
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Affiliation(s)
- Bernard A Ayanga
- Section of Nephrology, Department of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Shawn S Badal
- Section of Nephrology, Department of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Yin Wang
- Section of Nephrology, Department of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Daniel L Galvan
- Section of Nephrology, Department of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | | | - Paul T Schumacker
- Department of Pediatrics, Division of Neonatology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Farhad R Danesh
- Section of Nephrology, Department of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas; Pharmacology, Baylor College of Medicine, Houston, Texas; and
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13
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Ising C, Koehler S, Brähler S, Merkwirth C, Höhne M, Baris OR, Hagmann H, Kann M, Fabretti F, Dafinger C, Bloch W, Schermer B, Linkermann A, Brüning JC, Kurschat CE, Müller RU, Wiesner RJ, Langer T, Benzing T, Brinkkoetter PT. Inhibition of insulin/IGF-1 receptor signaling protects from mitochondria-mediated kidney failure. EMBO Mol Med 2015; 7:275-87. [PMID: 25643582 PMCID: PMC4364945 DOI: 10.15252/emmm.201404916] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mitochondrial dysfunction and alterations in energy metabolism have been implicated in a variety of human diseases. Mitochondrial fusion is essential for maintenance of mitochondrial function and requires the prohibitin ring complex subunit prohibitin-2 (PHB2) at the mitochondrial inner membrane. Here, we provide a link between PHB2 deficiency and hyperactive insulin/IGF-1 signaling. Deletion of PHB2 in podocytes of mice, terminally differentiated cells at the kidney filtration barrier, caused progressive proteinuria, kidney failure, and death of the animals and resulted in hyperphosphorylation of S6 ribosomal protein (S6RP), a known mediator of the mTOR signaling pathway. Inhibition of the insulin/IGF-1 signaling system through genetic deletion of the insulin receptor alone or in combination with the IGF-1 receptor or treatment with rapamycin prevented hyperphosphorylation of S6RP without affecting the mitochondrial structural defect, alleviated renal disease, and delayed the onset of kidney failure in PHB2-deficient animals. Evidently, perturbation of insulin/IGF-1 receptor signaling contributes to tissue damage in mitochondrial disease, which may allow therapeutic intervention against a wide spectrum of diseases.
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Affiliation(s)
- Christina Ising
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Sybille Koehler
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Sebastian Brähler
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Carsten Merkwirth
- Institute for Genetics, University of Cologne, Cologne, Germany Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA, USA
| | - Martin Höhne
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Systems Biology of Ageing Cologne (Sybacol) University of Cologne, Cologne, Germany
| | - Olivier R Baris
- Center for Physiology and Pathophysiology, Institute for Vegetative Physiology, University of Cologne, Cologne, Germany
| | - Henning Hagmann
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Martin Kann
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Francesca Fabretti
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Claudia Dafinger
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Wilhelm Bloch
- Department of Molecular and Cellular Sport Medicine, Institute of Cardiovascular Research and Sport Medicine, German Sport University Cologne, Cologne, Germany
| | - Bernhard Schermer
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Systems Biology of Ageing Cologne (Sybacol) University of Cologne, Cologne, Germany
| | - Andreas Linkermann
- Division of Nephrology and Hypertension, Christian-Albrechts-University, Kiel, Germany
| | - Jens C Brüning
- Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Systems Biology of Ageing Cologne (Sybacol) University of Cologne, Cologne, Germany Max Planck Institute for Metabolism Research, Cologne, Germany Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany
| | - Christine E Kurschat
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Systems Biology of Ageing Cologne (Sybacol) University of Cologne, Cologne, Germany
| | - Roman-Ulrich Müller
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Systems Biology of Ageing Cologne (Sybacol) University of Cologne, Cologne, Germany
| | - Rudolf J Wiesner
- Center for Physiology and Pathophysiology, Institute for Vegetative Physiology, University of Cologne, Cologne, Germany
| | - Thomas Langer
- Institute for Genetics, University of Cologne, Cologne, Germany Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Systems Biology of Ageing Cologne (Sybacol) University of Cologne, Cologne, Germany
| | - Thomas Benzing
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Systems Biology of Ageing Cologne (Sybacol) University of Cologne, Cologne, Germany
| | - Paul Thomas Brinkkoetter
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
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14
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In vivo RNA interference models of inducible and reversible Sirt1 knockdown in kidney cells. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 184:1940-56. [PMID: 24952428 DOI: 10.1016/j.ajpath.2014.03.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 02/26/2014] [Accepted: 03/06/2014] [Indexed: 02/07/2023]
Abstract
The silent mating type information regulation 2 homolog 1 gene (Sirt1) encodes an NAD-dependent deacetylase that modifies the activity of well-known transcriptional regulators affected in kidney diseases. Sirt1 is expressed in the kidney podocyte, but its function in the podocyte is not clear. Genetically engineered mice with inducible and reversible Sirt1 knockdown in widespread, podocyte-specific, or tubular-specific patterns were generated. We found that mice with 80% knockdown of renal Sirt1 expression have normal glomerular function under the basal condition. When challenged with doxorubicin (Adriamycin), these mice develop marked albuminuria, glomerulosclerosis, mitochondrial injury, and impaired autophagy of damaged mitochondria. Reversal of Sirt1 knockdown during the early phase of Adriamycin-induced nephropathy prevented the progression of glomerular injury and reduced the accumulation of dysmorphic mitochondria in podocytes but did not reverse the progression of albuminuria and glomerulosclerosis. Sirt1 knockdown mice with diabetes mellitus, which is known to cause mitochondrial dysfunction in the kidney, developed more albuminuria and mitochondrial dysfunction compared with diabetic mice without Sirt1 knockdown. In conclusion, these results demonstrate that our RNA interference-mediated Sirt1 knockdown models are valid and versatile tools for characterizing the function of Sirt1 in the kidney; Sirt1 plays a role in homeostatic maintenance of podocytes under the condition of mitochondrial stress/injury.
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15
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Lin J, Shi Y, Peng H, Shen X, Thomas S, Wang Y, Truong LD, Dryer SE, Hu Z, Xu J. Loss of PTEN promotes podocyte cytoskeletal rearrangement, aggravating diabetic nephropathy. J Pathol 2015; 236:30-40. [PMID: 25641678 DOI: 10.1002/path.4508] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 12/21/2014] [Accepted: 01/08/2015] [Indexed: 12/17/2022]
Abstract
In diabetic nephropathy (DN), podocyte cytoskeletal rearrangement occurs followed by podocyte effacement and the development of proteinuria. PTEN (phosphatase and tensin homologue) is a ubiquitously expressed phosphatase that plays a critical role in cell proliferation, cytoskeletal rearrangement, and motility. In mouse models of diabetes mellitus, PTEN expression is reportedly decreased in mesangial cells, contributing to expansion of the mesangial matrix, but how PTEN in the podocyte influences the development of DN is unknown. We observed that PTEN expression is down-regulated in the podocytes of diabetic db/db mice and patients with DN. In cultured podocytes, PTEN inhibition caused actin cytoskeletal rearrangement and this response was associated with unbalanced activation of the small GTPases Rac1/Cdc42 and RhoA. In mice treated with PTEN inhibitor, actin cytoskeletal rearrangement occurred in podocytes and was accompanied by increased albumin excretion. We also created mice with an inducible deletion of PTEN selectively in podocytes. These mice exhibited increased albumin excretion and moderate foot process effacement. When the mice were challenged with a high fat diet, podocyte-specific knockout of PTEN resulted in substantially increased proteinuria and glomeruloclerosis compared to control mice fed a high fat diet or mice with PTEN deletion fed a normal diet. These results indicate that PTEN is involved in the regulation of cytoskeletal rearrangement in podocytes and that loss of PTEN predisposes to the development of proteinuria and DN.
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Affiliation(s)
- Jamie Lin
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Yuanyuan Shi
- Nephrology Division, Second Hospital of Shanxi Medical University, Taiyuan, China
| | - Hui Peng
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Xiaojie Shen
- Renal Sections, Changhai Hospital, Shanghai, China
| | - Sandhya Thomas
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Yanlin Wang
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Luan D Truong
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Stuart E Dryer
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA.,Departments of Biology and Biochemistry, University of Houston, Houston, Texas, USA
| | - Zhaoyong Hu
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA.,Nephrology Division, Second Hospital of Shanxi Medical University, Taiyuan, China
| | - Jing Xu
- Renal Sections, Changhai Hospital, Shanghai, China
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16
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Ihara KI, Asanuma K, Fukuda T, Ohwada S, Yoshida M, Nishimori K. MAGI-2 is critical for the formation and maintenance of the glomerular filtration barrier in mouse kidney. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:2699-708. [PMID: 25108225 DOI: 10.1016/j.ajpath.2014.06.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 05/29/2014] [Accepted: 06/26/2014] [Indexed: 11/20/2022]
Abstract
Membrane-associated guanylate kinase inverted 2 (MAGI-2) is a tight junction protein in epithelial tissues. We previously reported the detailed expression patterns of MAGI-2 in mouse tissues, including kidney podocytes, based on results obtained from Venus knock-in mice for Magi2 locus. In the present study, homozygous deletion of the Magi2 gene in mice caused neonatal lethality, which was explained by podocyte morphological abnormalities and anuria. Immunohistological analysis showed that loss of MAGI-2 function induced a significant decrease in nephrin and dendrin at the slit diaphragm of the kidney, although other components of the slit diaphragm were unchanged. Furthermore, nuclear translocation of dendrin was observed in the podocytes of the MAGI-2-null mutants, along with enhanced expression of cathepsin L, which is reported to be critical for rearrangement of the actin cytoskeleton in podocytes. Expression analysis of the null mutants showed that loss of MAGI-2 function induces abnormal expression of various types of adhesion-related molecules. The present study is the first to demonstrate that MAGI-2 has a critical role in maintaining the functional structure of the slit diaphragm and that this molecule has an essential role in the functioning of the kidney filtration barrier.
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Affiliation(s)
- Kan-Ichiro Ihara
- Laboratory of Molecular Biology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, Sendai
| | - Katsuhiko Asanuma
- Division of Nephrology, Department of Internal Medicine, Juntendo University School of Medicine, Tokyo; Laboratory for Kidney Research, Medical Innovation Center, Graduate School of Medicine, Kyoto University, Kyoto
| | - Tomokazu Fukuda
- Laboratory of Animal Breeding and Genetics, Department of Animal Biology, Graduate School of Agricultural Science, Tohoku University, Sendai
| | - Shyuichi Ohwada
- Laboratory of Functional Morphology, Department of Animal Biology, Graduate School of Agricultural Science, Tohoku University, Sendai
| | - Midori Yoshida
- Division of Pathology, National Institute of Health Sciences, Tokyo, Japan
| | - Katsuhiko Nishimori
- Laboratory of Molecular Biology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, Sendai.
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17
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A multicolor podocyte reporter highlights heterogeneous podocyte changes in focal segmental glomerulosclerosis. Kidney Int 2013; 85:972-80. [PMID: 24284512 PMCID: PMC3987991 DOI: 10.1038/ki.2013.463] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 08/19/2013] [Accepted: 09/19/2013] [Indexed: 02/06/2023]
Abstract
In contrast to most glomerular diseases, the injury pattern in focal segmental glomerulosclerosis (FSGS) is highly heterogeneous, even though podocytes are genetically identical and exposed to the same environmental factors. To understand changes in individual podocytes, we generated and analyzed a stochastic multicolor Cre-reporter, encoding four fluorescent proteins. In these animals podocytes were randomly labeled allowing individual cells and their foot processes to be distinguished. In healthy animals podocyte size and structure showed little cell to cell variability. In the doxorubicin-induced FSGS model, fluorescent-labeled glomerular podocyte numbers decreased and fluorescent cells could be recovered from the urine. The size of the remaining podocytes showed a high degree of heterogeneity, some cells remained small, while others enlarged. Both enlarged and non-enlarged podocytes showed alterations in their foot process morphology. Thus, by the virtue of a multicolor cre-reporter, individual podocytes could be viewed in real time at a cellular resolution indicating a heterogeneous podocyte injury response during the pathogenesis of FSGS.
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18
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Hackl MJ, Burford JL, Villanueva K, Lam L, Suszták K, Schermer B, Benzing T, Peti-Peterdi J. Tracking the fate of glomerular epithelial cells in vivo using serial multiphoton imaging in new mouse models with fluorescent lineage tags. Nat Med 2013; 19:1661-6. [PMID: 24270544 PMCID: PMC3884556 DOI: 10.1038/nm.3405] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 10/07/2013] [Indexed: 12/13/2022]
Abstract
Podocytes are critical in the maintenance of a healthy glomerular filter, however they have been difficult to study in the intact kidney due to technical limitations. Here we report the development of serial multiphoton microscopy (MPM) of the same glomeruli over several days to visualize the motility of podocytes and parietal epithelial cells (PEC) in vivo. In Podocin-GFP mice podocytes formed sporadic multi-cellular clusters after unilateral ureteral ligation (UUO) and migrated into the parietal Bowman’s capsule. The tracking of single cells in Podocin-confetti mice featuring cell-specific expression of CFP, GFP, YFP, or RFP revealed the simultaneous migration of multiple podocytes. In PEPCK-GFP mice serial MPM found PEC-to-podocyte migration and nanotubule connections. Our data support the highly dynamic rather than static nature of the glomerular environment and cellular composition. Future application of this new approach promises to advance our understanding of the mechanisms of glomerular injury and regeneration.
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Affiliation(s)
- Matthias J Hackl
- 1] Department of Physiology and Biophysics, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, USA. [2] Department of Medicine, University of Southern California, Los Angeles, California, USA. [3] Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
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19
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Höhne M, Ising C, Hagmann H, Völker LA, Brähler S, Schermer B, Brinkkoetter PT, Benzing T. Light microscopic visualization of podocyte ultrastructure demonstrates oscillating glomerular contractions. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 182:332-8. [PMID: 23246153 DOI: 10.1016/j.ajpath.2012.11.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 10/17/2012] [Accepted: 11/01/2012] [Indexed: 12/23/2022]
Abstract
Podocytes, the visceral epithelial cells of the kidney glomerulus, elaborate primary and interdigitating secondary extensions to enwrap the glomerular capillaries. A hallmark of podocyte injury is the loss of unique ultrastructure and simplification of the cell shape, called foot process effacement, which is a classic feature of proteinuric kidney disease. Although several key pathways have been identified that control cytoskeletal regulation, actin dynamics, and polarity signaling, studies into the dynamic regulation of the podocyte structure have been hampered by the fact that ultrastructural analyses require electron microscopic imaging of fixed tissue. We developed a new technique that allows for visualization of podocyte foot processes using confocal laser scanning microscopy. The combination of inducible and mosaic expression of membrane-tagged fluorescent proteins in a small subset of podocytes enabled us to acquire light microscopic images of podocyte foot processes in unprecedented detail, even in living podocytes of freshly isolated glomeruli. Moreover, this technique visualized oscillatory glomerular contractions and confirmed the morphometric evaluations obtained in static electron microscopic images of podocyte processes. These data suggest that the new technique will provide an extremely powerful tool for studying the dynamics of podocyte ultrastructure.
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Affiliation(s)
- Martin Höhne
- Department II of Internal Medicine and the Center for Molecular Medicine Cologne, University of Cologne, 50937 Cologne, Germany
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20
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Wang W, Wang Y, Long J, Wang J, Haudek SB, Overbeek P, Chang BH, Schumacker PT, Danesh FR. Mitochondrial fission triggered by hyperglycemia is mediated by ROCK1 activation in podocytes and endothelial cells. Cell Metab 2012; 15:186-200. [PMID: 22326220 PMCID: PMC3278719 DOI: 10.1016/j.cmet.2012.01.009] [Citation(s) in RCA: 363] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 10/16/2011] [Accepted: 01/10/2012] [Indexed: 11/18/2022]
Abstract
Several lines of evidence suggest that mitochondrial dysfunction plays a critical role in the pathogenesis of microvascular complications of diabetes, including diabetic nephropathy. However, the signaling pathways by which hyperglycemia leads to mitochondrial dysfunction are not fully understood. Here we examined the role of Rho-associated coiled coil-containing protein kinase 1 (ROCK1) on mitochondrial dynamics by generating two diabetic mouse models with targeted deletions of ROCK1 and an inducible podocyte-specific knockin mouse expressing a constitutively active (cA) mutant of ROCK1. Our findings suggest that ROCK1 mediates hyperglycemia-induced mitochondrial fission by promoting dynamin-related protein-1 (Drp1) recruitment to the mitochondria. Deletion of ROCK1 in diabetic mice prevented mitochondrial fission, whereas podocyte-specific cA-ROCK1 mice exhibited increased mitochondrial fission. Importantly, we found that ROCK1 triggers mitochondrial fission by phosphorylating Drp1 at serine 600 residue. These findings provide insights into the unexpected role of ROCK1 in a signaling cascade that regulates mitochondrial dynamics.
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Affiliation(s)
- Wenjian Wang
- Department of Medicine-Nephrology, Baylor College of Medicine, Houston, TX
| | - Yin Wang
- Department of Medicine-Nephrology, Baylor College of Medicine, Houston, TX
| | - Jianyin Long
- Department of Medicine-Nephrology, Baylor College of Medicine, Houston, TX
| | - Jinrong Wang
- Department of Medicine-Nephrology, Baylor College of Medicine, Houston, TX
| | - Sandra B. Haudek
- Department of Medicine-Division of Cardiovascular Sciences, Baylor College of Medicine, Houston, TX
| | - Paul Overbeek
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX
| | - Benny H.J. Chang
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX
| | - Paul T. Schumacker
- Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Farhad R. Danesh
- Department of Medicine-Nephrology, Baylor College of Medicine, Houston, TX
- Department of Pharmacology, Baylor College of Medicine, Houston, TX
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21
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Long J, Wang Y, Wang W, Chang BHJ, Danesh FR. Identification of microRNA-93 as a novel regulator of vascular endothelial growth factor in hyperglycemic conditions. J Biol Chem 2010; 285:23457-65. [PMID: 20501654 DOI: 10.1074/jbc.m110.136168] [Citation(s) in RCA: 218] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Vascular endothelial growth factor (VEGF) is a dimeric glycoprotein that plays a crucial role in microvascular complications of diabetes, including diabetic nephropathy. However, the precise regulatory mechanisms governing VEGF expression in the diabetic milieu are still poorly understood. Here, we provide evidence that microRNA-93 (miR-93) regulates VEGF expression in experimental models of diabetes both in vitro and in vivo. Comparative microRNA expression profile arrays identified miR-93 as a signature microRNA in hyperglycemic conditions. We identified VEGF-A as a putative target of miR-93 in the kidney with a perfect complementarity between miR-93 and the 3'-untranslated region of vegfa in several species. When cotransfected with a luciferase reporter construct containing the mouse vegfa 3'-untranslated region, expression of miR-93 markedly decreased the luciferase activity. We showed that forced expression of miR-93 in cells abrogated VEGF protein secretion. Conversely, anti-miR-93 inhibitors increased VEGF release. Transfection of miR-93 also prevented the effect of high glucose on VEGF downstream targets. Using transgenic mice containing VEGF-LacZ bicistronic transcripts, we found that inhibition of glomerular miR-93 by peptide-conjugated morpholino oligomers elicited increased expression of VEGF. Our findings also indicate that high glucose decreases miR-93 expression by down-regulating the promoter of the host MCM7 gene. Taken together, our findings provide new insights into the role of miR-93 in VEGF signaling pathway and offer a potentially novel target in preventing the progression of diabetic nephropathy.
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Affiliation(s)
- Jianyin Long
- Division of Nephrology, Department of Medicine, Baylor College of Medicine, Houston, Texas 77030, USA
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