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Arif E, Solanki AK, Rahman B, Wolf B, Schnellmann RG, Nihalani D, Lipschutz JH. Role of the β 2-adrenergic receptor in podocyte injury and recovery. Pharmacol Rep 2024; 76:612-621. [PMID: 38668812 PMCID: PMC11126448 DOI: 10.1007/s43440-024-00594-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 03/28/2024] [Accepted: 04/03/2024] [Indexed: 05/25/2024]
Abstract
BACKGROUND Podocytes have a remarkable ability to recover from injury; however, little is known about the recovery mechanisms involved in this process. We recently showed that formoterol, a long-acting β2-adrenergic receptor (β2-AR) agonist, induced mitochondrial biogenesis (MB) in podocytes and led to renoprotection in mice. However, it is not clear whether this effect was mediated by formoterol acting through the β2-AR or if it occurred through "off-target" effects. METHODS We genetically deleted the β2-AR specifically in murine podocytes and used these mice to determine whether formoterol acting through the podocyte β2-AR alone is sufficient for recovery of renal filtration function following injury. The podocyte-specific β2-AR knockout mice (β2-ARfl/fl/PodCre) were generated by crossing β2-AR floxed mice with podocin Cre (B6.Cg-Tg(NPHS2-cre)295Lbh/J) mice. These mice were then subjected to both acute and chronic glomerular injury using nephrotoxic serum (NTS) and adriamycin (ADR), respectively. The extent of injury was evaluated by measuring albuminuria and histological and immunostaining analysis of the murine kidney sections. RESULTS A similar level of injury was observed in β2-AR knockout and control mice; however, the β2-ARfl/fl/PodCre mice failed to recover in response to formoterol. Functional evaluation of the β2-ARfl/fl/PodCre mice following injury plus formoterol showed similar albuminuria and glomerular injury to control mice that were not treated with formoterol. CONCLUSIONS These results indicate that the podocyte β2-AR is a critical component of the recovery mechanism and may serve as a novel therapeutic target for treating podocytopathies.
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Affiliation(s)
- Ehtesham Arif
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Clinical Science Building 822N, 96 Jonathan Lucas Street, Charleston, SC, 29425, USA
| | - Ashish K Solanki
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Clinical Science Building 822N, 96 Jonathan Lucas Street, Charleston, SC, 29425, USA
| | - Bushra Rahman
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Clinical Science Building 822N, 96 Jonathan Lucas Street, Charleston, SC, 29425, USA
| | - Bethany Wolf
- Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Rick G Schnellmann
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ, USA
- Southern Arizona VA Health Care System, Tucson, AZ, USA
| | - Deepak Nihalani
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Clinical Science Building 822N, 96 Jonathan Lucas Street, Charleston, SC, 29425, USA
| | - Joshua H Lipschutz
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Clinical Science Building 822N, 96 Jonathan Lucas Street, Charleston, SC, 29425, USA.
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2
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Reghuvaran AC, Lin Q, Basgen JM, Banu K, Shi H, Vashist A, Pell J, Perinchery S, He JC, Moledina D, Wilson FP, Menon MC. Comparative evaluation of glomerular morphometric techniques reveals differential technical artifacts between focal segmental glomerulosclerosis and normal glomeruli. Physiol Rep 2023; 11:e15688. [PMID: 37423891 PMCID: PMC10329935 DOI: 10.14814/phy2.15688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 04/18/2023] [Accepted: 04/21/2023] [Indexed: 07/11/2023] Open
Abstract
Morphometric estimates of mean or individual glomerular volume (MGV, IGV) have biological implications, over and above qualitative histologic data. However, morphometry is time-consuming and requires expertise limiting its utility in clinical cases. We evaluated MGV and IGV using plastic- and paraffin-embedded tissue from 10 control and 10 focal segmental glomerulosclerosis (FSGS) mice (aging and 5/6th nephrectomy models) using the gold standard Cavalieri (Cav) method versus the 2-profile and Weibel-Gomez (WG) methods and a novel 3-profile method. We compared accuracy, bias and precision, and quantified results obtained when sampling differing numbers of glomeruli. In both FSGS and controls, we identified an acceptable precision for MGV of 10-glomerular sampling versus 20-glomerular sampling using the Cav method, while 5-glomerular sampling was less precise. In plastic tissue, 2- or 3-profile MGVs showed greater concordance with MGV when using Cav, versus MGV with WG. IGV comparisons using the same glomeruli reported a consistent underestimation bias with both 2- or 3-profile methods versus the Cav method. FSGS glomeruli showed wider variations in bias estimation than controls. Our 3-profile method offered incremental benefit to the 2-profile method in both IGV and MGV estimation (improved correlation coefficient, Lin's concordance and reduced bias). In our control animals, we quantified a shrinkage artifact of 52% from tissue processed for paraffin-embedded versus plastic-embedded tissue. FSGS glomeruli showed overall reduced shrinkage albeit with variable artifact signifying periglomerular/glomerular fibrosis. A novel 3-profile method offers slightly improved concordance with reduced bias versus 2-profile. Our findings have implications for future studies using glomerular morphometry.
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Affiliation(s)
- Anand C. Reghuvaran
- Division of Nephrology, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - Qisheng Lin
- Department of Nephrology, Renji Hospital, School of MedicineShanghai Jiao Tong UniversityShanghaiPeople's Republic of China
| | - John M. Basgen
- Morphometry and Stereology LaboratoryCharles R. Drew University of Medicine and ScienceLos AngelesCaliforniaUSA
| | - Khadija Banu
- Division of Nephrology, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - Hongmei Shi
- Division of Nephrology, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - Anushree Vashist
- Division of Nephrology, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - John Pell
- Division of Nephrology, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - Sudhir Perinchery
- Department of PathologyYale University School of MedicineNew HavenConnecticutUSA
| | - John C. He
- Division of Nephrology, Department of MedicineIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | - Dennis Moledina
- Division of Nephrology, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
- Clinical Translational Research Accelerator, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - F. Perry Wilson
- Division of Nephrology, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
- Clinical Translational Research Accelerator, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - Madhav C. Menon
- Division of Nephrology, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
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3
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Banu K, Lin Q, Basgen JM, Planoutene M, Wei C, Reghuvaran AC, Tian X, Shi H, Garzon F, Garzia A, Chun N, Cumpelik A, Santeusanio AD, Zhang W, Das B, Salem F, Li L, Ishibe S, Cantley LG, Kaufman L, Lemley KV, Ni Z, He JC, Murphy B, Menon MC. AMPK mediates regulation of glomerular volume and podocyte survival. JCI Insight 2021; 6:e150004. [PMID: 34473647 PMCID: PMC8525649 DOI: 10.1172/jci.insight.150004] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 09/01/2021] [Indexed: 12/20/2022] Open
Abstract
Herein, we report that Shroom3 knockdown, via Fyn inhibition, induced albuminuria with foot process effacement (FPE) without focal segmental glomerulosclerosis (FSGS) or podocytopenia. Interestingly, knockdown mice had reduced podocyte volumes. Human minimal change disease (MCD), where podocyte Fyn inactivation was reported, also showed lower glomerular volumes than FSGS. We hypothesized that lower glomerular volume prevented the progression to podocytopenia. To test this hypothesis, we utilized unilateral and 5/6th nephrectomy models in Shroom3-KD mice. Knockdown mice exhibited less glomerular and podocyte hypertrophy after nephrectomy. FYN-knockdown podocytes had similar reductions in podocyte volume, implying that Fyn was downstream of Shroom3. Using SHROOM3 or FYN knockdown, we confirmed reduced podocyte protein content, along with significantly increased phosphorylated AMPK, a negative regulator of anabolism. AMPK activation resulted from increased cytoplasmic redistribution of LKB1 in podocytes. Inhibition of AMPK abolished the reduction in glomerular volume and induced podocytopenia in mice with FPE, suggesting a protective role for AMPK activation. In agreement with this, treatment of glomerular injury models with AMPK activators restricted glomerular volume, podocytopenia, and progression to FSGS. Glomerular transcriptomes from MCD biopsies also showed significant enrichment of Fyn inactivation and Ampk activation versus FSGS glomeruli. In summary, we demonstrated the important role of AMPK in glomerular volume regulation and podocyte survival. Our data suggest that AMPK activation adaptively regulates glomerular volume to prevent podocytopenia in the context of podocyte injury.
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Affiliation(s)
- Khadija Banu
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Division of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Qisheng Lin
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Nephrology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - John M Basgen
- Morphometry and Stereology Laboratory, Charles R. Drew University of Medicine and Science, Los Angeles, California, USA
| | - Marina Planoutene
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Chengguo Wei
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Anand C Reghuvaran
- Division of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Xuefei Tian
- Division of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Hongmei Shi
- Division of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Felipe Garzon
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Aitor Garzia
- Laboratory of RNA Molecular Biology, The Rockefeller University, New York, New York, USA
| | - Nicholas Chun
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Arun Cumpelik
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Andrew D Santeusanio
- Division of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Weijia Zhang
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Bhaskar Das
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Fadi Salem
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Li Li
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Shuta Ishibe
- Division of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Lloyd G Cantley
- Division of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Lewis Kaufman
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Kevin V Lemley
- Department of Pediatrics, Children's Hospital Los Angeles, University of Southern California, Los Angeles, California, USA
| | - Zhaohui Ni
- Department of Nephrology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - John Cijiang He
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Barbara Murphy
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Madhav C Menon
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Division of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
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4
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Marahrens B, Schulze A, Wysocki J, Lin MH, Ye M, Kanwar YS, Bader M, Velez JCQ, Miner JH, Batlle D. Knockout of aminopeptidase A in mice causes functional alterations and morphological glomerular basement membrane changes in the kidneys. Kidney Int 2020; 99:900-913. [PMID: 33316280 DOI: 10.1016/j.kint.2020.11.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 10/28/2020] [Accepted: 11/19/2020] [Indexed: 11/29/2022]
Abstract
Aminopeptidase A is one of the most potent enzymes within the renin-angiotensin system in terms of angiotensin II degradation. Here, we examined whether there is a kidney phenotype and any compensatory changes in other renin angiotensin system enzymes involved in the metabolism of angiotensin II associated with aminopeptidase A deficiency. Kidneys harvested from aminopeptidase A knockout mice were examined by light and electron microscopy, immunohistochemistry and immunofluorescence. Kidney angiotensin II levels and the ability of renin angiotensin system enzymes in the glomerulus to degrade angiotensin II ex vivo, their activities, protein and mRNA levels in kidney lysates were evaluated. Knockout mice had increased blood pressure and mild glomerular mesangial expansion without significant albuminuria. By electron microscopy, knockout mice exhibited a mild increase of the mesangial matrix, moderate thickening of the glomerular basement membrane but a striking appearance of knob-like structures. These knobs were seen in both male and female mice and persisted after the treatment of hypertension. In isolated glomeruli from knockout mice, the level of angiotensin II was more than three-fold higher as compared to wild type control mice. In kidney lysates from knockout mice angiotensin converting enzyme activity, protein and mRNA levels were markedly decreased possibly as a compensatory mechanism to reduce angiotensin II formation. Thus, our findings support a role for aminopeptidase A in the maintenance of glomerular structure and intra-kidney homeostasis of angiotensin peptides.
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Affiliation(s)
- Benedikt Marahrens
- Division of Nephrology and Hypertension, Department of Medicine, Northwestern University/Feinberg School of Medicine, Chicago, Illinois, USA; Charité University Medicine Berlin, Berlin, Germany
| | - Arndt Schulze
- Division of Nephrology and Hypertension, Department of Medicine, Northwestern University/Feinberg School of Medicine, Chicago, Illinois, USA; Charité University Medicine Berlin, Berlin, Germany
| | - Jan Wysocki
- Division of Nephrology and Hypertension, Department of Medicine, Northwestern University/Feinberg School of Medicine, Chicago, Illinois, USA
| | - Meei-Hua Lin
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Minghao Ye
- Division of Nephrology and Hypertension, Department of Medicine, Northwestern University/Feinberg School of Medicine, Chicago, Illinois, USA
| | - Yashpal S Kanwar
- Department of Pathology, Northwestern University/Feinberg School of Medicine, Chicago, Illinois, USA
| | - Michael Bader
- Charité University Medicine Berlin, Berlin, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin, Germany; Max-Delbrück-Center for Molecular Medicine, Berlin, Germany; Institute for Biology, University of Lübeck, Lübeck, Germany
| | - Juan Carlos Q Velez
- Department of Nephrology, Ochsner Clinic Foundation, New Orleans, Louisiana, USA
| | - Jeffrey H Miner
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Daniel Batlle
- Division of Nephrology and Hypertension, Department of Medicine, Northwestern University/Feinberg School of Medicine, Chicago, Illinois, USA.
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5
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Pugh D, Dhaun N. Hypertension and Vascular Inflammation: Another Piece of the Genetic Puzzle. Hypertension 2020; 77:190-192. [PMID: 33296247 DOI: 10.1161/hypertensionaha.120.16420] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Dan Pugh
- University/BHF Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of Edinburgh, United Kingdom
| | - Neeraj Dhaun
- University/BHF Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of Edinburgh, United Kingdom
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6
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Vargas F, Wangesteen R, Rodríguez-Gómez I, García-Estañ J. Aminopeptidases in Cardiovascular and Renal Function. Role as Predictive Renal Injury Biomarkers. Int J Mol Sci 2020; 21:E5615. [PMID: 32764495 PMCID: PMC7460675 DOI: 10.3390/ijms21165615] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/23/2020] [Accepted: 08/03/2020] [Indexed: 01/08/2023] Open
Abstract
Aminopeptidases (APs) are metalloenzymes that hydrolyze peptides and polypeptides by scission of the N-terminus amino acid and that also participate in the intracellular final digestion of proteins. APs play an important role in protein maturation, signal transduction, and cell-cycle control, among other processes. These enzymes are especially relevant in the control of cardiovascular and renal functions. APs participate in the regulation of the systemic and local renin-angiotensin system and also modulate the activity of neuropeptides, kinins, immunomodulatory peptides, and cytokines, even contributing to cholesterol uptake and angiogenesis. This review focuses on the role of four key APs, aspartyl-, alanyl-, glutamyl-, and leucyl-cystinyl-aminopeptidases, in the control of blood pressure (BP) and renal function and on their association with different cardiovascular and renal diseases. In this context, the effects of AP inhibitors are analyzed as therapeutic tools for BP control and renal diseases. Their role as urinary biomarkers of renal injury is also explored. The enzymatic activities of urinary APs, which act as hydrolyzing peptides on the luminal surface of the renal tubule, have emerged as early predictive renal injury biomarkers in both acute and chronic renal nephropathies, including those induced by nephrotoxic agents, obesity, hypertension, or diabetes. Hence, the analysis of urinary AP appears to be a promising diagnostic and prognostic approach to renal disease in both research and clinical settings.
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Affiliation(s)
- Félix Vargas
- Depto. Fisiologia, Fac. Medicina, Universidad de Granada, 18071 Granada, Spain
| | | | | | - Joaquín García-Estañ
- Depto. Fisiologia, Fac. Medicina, IMIB, Universidad de Murcia, 30120 Murcia, Spain
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7
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Zhang YY, Yu Y, Yu C. Antifibrotic Roles of RAAS Blockers: Update. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1165:671-691. [PMID: 31399990 PMCID: PMC7121580 DOI: 10.1007/978-981-13-8871-2_33] [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] [Indexed: 02/08/2023]
Abstract
The rennin-angiotensin-aldosterone system (RAAS) has been well documented in regulating blood pressure, fluid volume, and sodium balance. Overactivity of RAAS promotes both systemic and regional glomerular capillary hypertension, which could induce hemodynamic injury to the glomerulus, leading to kidney damage and renal fibrosis via profibrotic and proinflammatory pathway. Therefore, the use of RAAS inhibitors (i.e., ACEIs, ARBs, and MRAs) as the optional therapy has been demonstrated to prevent proteinuria, and kidney fibrosis and slow the decline of renal function effectively in the process of kidney disease during the last few decades. Recently, several new components of the RAAS have been discovered, including ACE2 and the corresponding ACE2/Ang (1-7)/Mas axis, which are also present in the kidney. Besides the classic RAAS inhibitors target the angiotensin-AT1-aldosterone axis, with the expanding knowledge about RAAS, a number of potential therapeutic targets in this system is emerging. Newer agents that are more specific are being developed. The present chapter outlines the insights of the RAAS agents (classic RAAS antagonists/the new RAAS drugs), and discusses its clinical application in the combat of renal fibrosis.
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Affiliation(s)
- Ying-Ying Zhang
- Department of Nephrology, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Ying Yu
- Department of Nephrology, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Chen Yu
- Department of Nephrology, Tongji Hospital, Tongji University School of Medicine, Shanghai, China.
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8
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Arif E, Solanki AK, Srivastava P, Rahman B, Fitzgibbon WR, Deng P, Budisavljevic MN, Baicu CF, Zile MR, Megyesi J, Janech MG, Kwon SH, Collier J, Schnellmann RG, Nihalani D. Mitochondrial biogenesis induced by the β2-adrenergic receptor agonist formoterol accelerates podocyte recovery from glomerular injury. Kidney Int 2019; 96:656-673. [PMID: 31262488 PMCID: PMC6708766 DOI: 10.1016/j.kint.2019.03.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 03/07/2019] [Accepted: 03/28/2019] [Indexed: 01/14/2023]
Abstract
Podocytes have limited ability to recover from injury. Here, we demonstrate that increased mitochondrial biogenesis, to meet the metabolic and energy demand of a cell, accelerates podocyte recovery from injury. Analysis of events induced during podocyte injury and recovery showed marked upregulation of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), a transcriptional co-activator of mitochondrial biogenesis, and key components of the mitochondrial electron transport chain. To evaluate our hypothesis that increasing mitochondrial biogenesis enhanced podocyte recovery from injury, we treated injured podocytes with formoterol, a potent, specific, and long-acting β2-adrenergic receptor agonist that induces mitochondrial biogenesis in vitro and in vivo. Formoterol increased mitochondrial biogenesis and restored mitochondrial morphology and the injury-induced changes to the organization of the actin cytoskeleton in podocytes. Importantly, β2-adrenergic receptors were found to be present on podocyte membranes. Their knockdown attenuated formoterol-induced mitochondrial biogenesis. To determine the potential clinical relevance of these findings, mouse models of acute nephrotoxic serum nephritis and chronic (Adriamycin [doxorubicin]) glomerulopathy were used. Mice were treated with formoterol post-injury when glomerular dysfunction was established. Strikingly, formoterol accelerated the recovery of glomerular function by reducing proteinuria and ameliorating kidney pathology. Furthermore, formoterol treatment reduced cellular apoptosis and increased the expression of the mitochondrial biogenesis marker PGC-1α and multiple electron transport chain proteins. Thus, our results support β2-adrenergic receptors as novel therapeutic targets and formoterol as a therapeutic compound for treating podocytopathies.
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Affiliation(s)
- Ehtesham Arif
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Ashish K Solanki
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Pankaj Srivastava
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Bushra Rahman
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Wayne R Fitzgibbon
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Peifeng Deng
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Milos N Budisavljevic
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Catalin F Baicu
- Division of Cardiology, Medical University of South Carolina, Charleston, South Carolina, USA; Ralph H. Johnson VA Medical Center, Charleston, South Carolina, USA
| | - Michael R Zile
- Division of Cardiology, Medical University of South Carolina, Charleston, South Carolina, USA; Ralph H. Johnson VA Medical Center, Charleston, South Carolina, USA
| | - Judit Megyesi
- John C McClelland VA Hospital, Little Rock, Arkansas, USA
| | | | - Sang-Ho Kwon
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, Georgia, USA
| | - Justin Collier
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Rick G Schnellmann
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona, USA; Southern Arizona VA Health Care System, Tucson, Arizona, USA.
| | - Deepak Nihalani
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA.
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9
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Nihalani D, Solanki AK, Arif E, Srivastava P, Rahman B, Zuo X, Dang Y, Fogelgren B, Fermin D, Gillies CE, Sampson MG, Lipschutz JH. Disruption of the exocyst induces podocyte loss and dysfunction. J Biol Chem 2019; 294:10104-10119. [PMID: 31073028 PMCID: PMC6664173 DOI: 10.1074/jbc.ra119.008362] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/06/2019] [Indexed: 11/06/2022] Open
Abstract
Although the slit diaphragm proteins in podocytes are uniquely organized to maintain glomerular filtration assembly and function, little is known about the underlying mechanisms that participate in trafficking these proteins to the correct location for development and homeostasis. Identifying these mechanisms will likely provide novel targets for therapeutic intervention to preserve podocyte function following glomerular injury. Analysis of structural variation in cases of human nephrotic syndrome identified rare heterozygous deletions of EXOC4 in two patients. This suggested that disruption of the highly-conserved eight-protein exocyst trafficking complex could have a role in podocyte dysfunction. Indeed, mRNA profiling of injured podocytes identified significant exocyst down-regulation. To test the hypothesis that the exocyst is centrally involved in podocyte development/function, we generated homozygous podocyte-specific Exoc5 (a central exocyst component that interacts with Exoc4) knockout mice that showed massive proteinuria and died within 4 weeks of birth. Histological and ultrastructural analysis of these mice showed severe glomerular defects with increased fibrosis, proteinaceous casts, effaced podocytes, and loss of the slit diaphragm. Immunofluorescence analysis revealed that Neph1 and Nephrin, major slit diaphragm constituents, were mislocalized and/or lost. mRNA profiling of Exoc5 knockdown podocytes showed that vesicular trafficking was the most affected cellular event. Mapping of signaling pathways and Western blot analysis revealed significant up-regulation of the mitogen-activated protein kinase and transforming growth factor-β pathways in Exoc5 knockdown podocytes and in the glomeruli of podocyte-specific Exoc5 KO mice. Based on these data, we propose that exocyst-based mechanisms regulate Neph1 and Nephrin signaling and trafficking, and thus podocyte development and function.
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Affiliation(s)
- Deepak Nihalani
- From the Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425,
| | - Ashish K Solanki
- From the Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Ehtesham Arif
- From the Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Pankaj Srivastava
- From the Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Bushra Rahman
- From the Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Xiaofeng Zuo
- From the Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Yujing Dang
- From the Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Ben Fogelgren
- the Department of Anatomy, Biochemistry, and Physiology, University of Hawaii at Manoa, Honolulu, Hawaii 96813
| | | | | | - Matthew G Sampson
- the Department of Pediatrics-Nephrology and.,Center for Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109, and
| | - Joshua H Lipschutz
- From the Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425.,the Department of Medicine, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina 29401
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Arif E, Solanki AK, Srivastava P, Rahman B, Tash BR, Holzman LB, Janech MG, Martin R, Knölker HJ, Fitzgibbon WR, Deng P, Budisavljevic MN, Syn WK, Wang C, Lipschutz JH, Kwon SH, Nihalani D. The motor protein Myo1c regulates transforming growth factor-β-signaling and fibrosis in podocytes. Kidney Int 2019; 96:139-158. [PMID: 31097328 DOI: 10.1016/j.kint.2019.02.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 02/07/2019] [Accepted: 02/14/2019] [Indexed: 01/19/2023]
Abstract
Transforming growth factor-β (TGF-β) is known to play a critical role in the pathogenesis of many progressive podocyte diseases. However, the molecular mechanisms regulating TGF-β signaling in podocytes remain unclear. Using a podocyte-specific myosin (Myo)1c knockout, we demonstrate whether Myo1c is critical for TGF-β-signaling in podocyte disease pathogenesis. Specifically, podocyte-specific Myo1c knockout mice were resistant to fibrotic injury induced by Adriamycin or nephrotoxic serum. Further, loss of Myo1c also protected from injury in the TGF-β-dependent unilateral ureteral obstruction mouse model of renal interstitial fibrosis. Mechanistic analyses showed that loss of Myo1c significantly blunted TGF-β signaling through downregulation of canonical and non-canonical TGF-β pathways. Interestingly, nuclear rather than the cytoplasmic Myo1c was found to play a central role in controlling TGF-β signaling through transcriptional regulation. Differential expression analysis of nuclear Myo1c-associated gene promoters showed that nuclear Myo1c targeted the TGF-β responsive gene growth differentiation factor (GDF)-15 and directly bound to the GDF-15 promoter. Importantly, GDF15 was found to be involved in podocyte pathogenesis, where GDF15 was upregulated in glomeruli of patients with focal segmental glomerulosclerosis. Thus, Myo1c-mediated regulation of TGF-β-responsive genes is central to the pathogenesis of podocyte injury. Hence, inhibiting this process may have clinical application in treating podocytopathies.
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Affiliation(s)
- Ehtesham Arif
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Ashish K Solanki
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Pankaj Srivastava
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Bushra Rahman
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Brian R Tash
- Department of Medicine, Renal Electrolyte and Hypertension Division, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Lawrence B Holzman
- Department of Medicine, Renal Electrolyte and Hypertension Division, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Michael G Janech
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA; College of Charleston, Charleston, South Carolina, USA
| | - René Martin
- Department of Chemistry, TU Dresden, Dresden, Germany
| | | | - Wayne R Fitzgibbon
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Peifeng Deng
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Milos N Budisavljevic
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Wing-Kin Syn
- Department of Gastroenterology & Hepatology, Medical University of South Carolina, Charleston, South Carolina, USA; Section of Gastroenterology, Ralph H Johnson VA Medical Center, Charleston, South Carolina, USA; Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country, (UPV/EHU), Vizcaya, Spain
| | - Cindy Wang
- Department of Gastroenterology & Hepatology, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Joshua H Lipschutz
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Sang-Ho Kwon
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, Georgia, USA
| | - Deepak Nihalani
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA.
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