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Abstract
AKI affects approximately 13.3 million people around the world each year, causing CKD and/or mortality. The mammalian kidney cannot generate new nephrons after postnatal renal damage and regenerative therapies for AKI are not available. Human kidney tissue culture systems can complement animal models of AKI and/or address some of their limitations. Donor-derived somatic cells, such as renal tubule epithelial cells or cell lines (RPTEC/hTERT, ciPTEC, HK-2, Nki-2, and CIHP-1), have been used for decades to permit drug toxicity screening and studies into potential AKI mechanisms. However, tubule cell lines do not fully recapitulate tubular epithelial cell properties in situ when grown under classic tissue culture conditions. Improving tissue culture models of AKI would increase our understanding of the mechanisms, leading to new therapeutics. Human pluripotent stem cells (hPSCs) can be differentiated into kidney organoids and various renal cell types. Injury to human kidney organoids results in renal cell-type crosstalk and upregulation of kidney injury biomarkers that are difficult to induce in primary tubule cell cultures. However, current protocols produce kidney organoids that are not mature and contain off-target cell types. Promising bioengineering techniques, such as bioprinting and "kidney-on-a-chip" methods, as applied to kidney nephrotoxicity modeling advantages and limitations are discussed. This review explores the mechanisms and detection of AKI in tissue culture, with an emphasis on bioengineered approaches such as human kidney organoid models.
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Affiliation(s)
- Julie Bejoy
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Eddie S. Qian
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Lauren E. Woodard
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee,Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
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2
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Deleersnijder D, Callemeyn J, Arijs I, Naesens M, Van Craenenbroeck AH, Lambrechts D, Sprangers B. Current Methodological Challenges of Single-Cell and Single-Nucleus RNA-Sequencing in Glomerular Diseases. J Am Soc Nephrol 2021; 32:1838-1852. [PMID: 34140401 PMCID: PMC8455274 DOI: 10.1681/asn.2021020157] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Single-cell RNA sequencing (scRNA-seq) and single-nucleus RNA-seq (snRNA-seq) allow transcriptomic profiling of thousands of cells from a renal biopsy specimen at a single-cell resolution. Both methods are promising tools to unravel the underlying pathophysiology of glomerular diseases. This review provides an overview of the technical challenges that should be addressed when designing single-cell transcriptomics experiments that focus on glomerulopathies. The isolation of glomerular cells from core needle biopsy specimens for single-cell transcriptomics remains difficult and depends upon five major factors. First, core needle biopsies generate little tissue material, and several samples are required to identify glomerular cells. Second, both fresh and frozen tissue samples may yield glomerular cells, although every experimental pipeline has different (dis)advantages. Third, enrichment for glomerular cells in human tissue before single-cell analysis is challenging because no effective standardized pipelines are available. Fourth, the current warm cell-dissociation protocols may damage glomerular cells and induce transcriptional artifacts, which can be minimized by using cold dissociation techniques at the cost of less efficient cell dissociation. Finally, snRNA-seq methods may be superior to scRNA-seq in isolating glomerular cells; however, the efficacy of snRNA-seq on core needle biopsy specimens remains to be proven. The field of single-cell omics is rapidly evolving, and the integration of these techniques in multiomics assays will undoubtedly create new insights in the complex pathophysiology of glomerular diseases.
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Affiliation(s)
- Dries Deleersnijder
- Department of Microbiology, Immunology and Transplantation, Laboratory of Molecular Immunology, Rega Institute, KU Leuven, Leuven, Belgium,Division of Nephrology, University Hospitals Leuven, Leuven, Belgium
| | - Jasper Callemeyn
- Division of Nephrology, University Hospitals Leuven, Leuven, Belgium,Department of Microbiology, Immunology and Transplantation, Nephrology and Renal Transplantation Research Group, KU Leuven, Leuven, Belgium
| | - Ingrid Arijs
- Laboratory for Translational Genetics, Department of Human Genetics, KU Leuven, Leuven, Belgium,Vlaams Instituut voor Biotechnologie Center for Cancer Biology, Leuven, Belgium
| | - Maarten Naesens
- Division of Nephrology, University Hospitals Leuven, Leuven, Belgium,Department of Microbiology, Immunology and Transplantation, Nephrology and Renal Transplantation Research Group, KU Leuven, Leuven, Belgium
| | - Amaryllis H. Van Craenenbroeck
- Division of Nephrology, University Hospitals Leuven, Leuven, Belgium,Department of Microbiology, Immunology and Transplantation, Nephrology and Renal Transplantation Research Group, KU Leuven, Leuven, Belgium
| | - Diether Lambrechts
- Laboratory for Translational Genetics, Department of Human Genetics, KU Leuven, Leuven, Belgium,Vlaams Instituut voor Biotechnologie Center for Cancer Biology, Leuven, Belgium
| | - Ben Sprangers
- Department of Microbiology, Immunology and Transplantation, Laboratory of Molecular Immunology, Rega Institute, KU Leuven, Leuven, Belgium,Division of Nephrology, University Hospitals Leuven, Leuven, Belgium,Correspondence: Prof. Ben Sprangers, Department of Microbiology, Immunology and Transplantation, Laboratory of Molecular Immunology (Rega Institute), KU Leuven, Herestraat 49, Leuven 3000, Belgium.
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3
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Abstract
The kidney contains a network of lymphatic vessels that clear fluid, small molecules, and cells from the renal interstitium. Through modulating immune responses and via crosstalk with surrounding renal cells, lymphatic vessels have been implicated in the progression and maintenance of kidney disease. In this Review, we provide an overview of the development, structure, and function of lymphatic vessels in the healthy adult kidney. We then highlight the contributions of lymphatic vessels to multiple forms of renal pathology, emphasizing CKD, transplant rejection, and polycystic kidney disease and discuss strategies to target renal lymphatics using genetic and pharmacologic approaches. Overall, we argue the case for lymphatics playing a fundamental role in renal physiology and pathology and treatments modulating these vessels having therapeutic potential across the spectrum of kidney disease.
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Affiliation(s)
- Daniyal J Jafree
- Developmental Biology and Cancer Programme, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom.,MB/PhD Programme, Faculty of Medical Sciences, University College London, London, United Kingdom
| | - David A Long
- Developmental Biology and Cancer Programme, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
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4
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Farmer LK, Rollason R, Whitcomb DJ, Ni L, Goodliff A, Lay AC, Birnbaumer L, Heesom KJ, Xu SZ, Saleem MA, Welsh GI. TRPC6 Binds to and Activates Calpain, Independent of Its Channel Activity, and Regulates Podocyte Cytoskeleton, Cell Adhesion, and Motility. J Am Soc Nephrol 2019; 30:1910-1924. [PMID: 31416818 DOI: 10.1681/asn.2018070729] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 06/17/2019] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Mutations in the transient receptor potential channel 6 (TRPC6) gene are associated with an inherited form of FSGS. Despite widespread expression, patients with TRPC6 mutations do not present with any other pathologic phenotype, suggesting that this protein has a unique yet unidentified role within the target cell for FSGS, the kidney podocyte. METHODS We generated a stable TRPC6 knockout podocyte cell line from TRPC6 knockout mice. These cells were engineered to express wild-type TRPC6, a dominant negative TRPC6 mutation, or either of two disease-causing mutations of TRPC6, G109S or K874*. We extensively characterized these cells using motility, detachment, and calpain activity assays; immunofluorescence; confocal or total internal reflection fluorescence microscopy; and western blotting. RESULTS Compared with wild-type cells, TRPC6-/- podocytes are less motile and more adhesive, with an altered actin cytoskeleton. We found that TRPC6 binds to ERK1/2 and the actin regulatory proteins, caldesmon (a calmodulin- and actin-binding protein) and calpain 1 and 2 (calcium-dependent cysteine proteases that control the podocyte cytoskeleton, cell adhesion, and motility via cleavage of paxillin, focal adhesion kinase, and talin). Knockdown or expression of the truncated K874* mutation (but not expression of the gain-of-function G019S mutation or dominant negative mutant of TRPC6) results in the mislocalization of calpain 1 and 2 and significant downregulation of calpain activity; this leads to altered podocyte cytoskeleton, motility, and adhesion-characteristics of TRPC6 -/- podocytes. CONCLUSIONS Our data demonstrate that independent of TRPC6 channel activity, the physical interaction between TRPC6 and calpain in the podocyte is important for cell motility and detachment and demonstrates a scaffolding role of the TRPC6 protein in disease.
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Affiliation(s)
| | | | - Daniel J Whitcomb
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Bristol Medical School, and
| | - Lan Ni
- Bristol Renal, Bristol Medical School
| | | | | | - Lutz Birnbaumer
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina.,Faculty of Medical Sciences, Institute of Biomedical Research, Catholic University of Argentina, Buenos Aires, Argentina; and
| | - Kate J Heesom
- Proteomics Facility, University of Bristol, Bristol, United Kingdom
| | - Shang-Zhong Xu
- Centre for Cardiovascular and Metabolic Research, Hull York Medical School, University of Hull, Hull, United Kingdom
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5
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Dlugos CP, Picciotto C, Lepa C, Krakow M, Stöber A, Eddy ML, Weide T, Jeibmann A, P Krahn M, Van Marck V, Klingauf J, Ricker A, Wedlich-Söldner R, Pavenstädt H, Klämbt C, George B. Nephrin Signaling Results in Integrin β1 Activation. J Am Soc Nephrol 2019; 30:1006-1019. [PMID: 31097607 DOI: 10.1681/asn.2018040362] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 03/18/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Patients with certain mutations in the gene encoding the slit diaphragm protein Nephrin fail to develop functional slit diaphragms and display severe proteinuria. Many adult-onset glomerulopathies also feature alterations in Nephrin expression and function. Nephrin signals from the podocyte slit diaphragm to the Actin cytoskeleton by recruiting proteins that can interact with C3G, a guanine nucleotide exchange factor of the small GTPase Rap1. Because Rap activity affects formation of focal adhesions, we hypothesized that Nephrin transmits signals to the Integrin receptor complex, which mediates podocyte adhesion to the extracellular matrix. METHODS To investigate Nephrin's role in transmitting signals to the Integrin receptor complex, we conducted genetic studies in Drosophila nephrocytes and validated findings from Drosophila in a cultured human podocyte model. RESULTS Drosophila nephrocytes form a slit diaphragm-like filtration barrier and express the Nephrin ortholog Sticks and stones (Sns). A genetic screen identified c3g as necessary for nephrocyte function. In vivo, nephrocyte-specific gene silencing of sns or c3g compromised nephrocyte filtration and caused nephrocyte diaphragm defects. Nephrocytes with impaired Sns or C3G expression displayed an altered localization of Integrin and the Integrin-associated protein Talin. Furthermore, gene silencing of c3g partly rescued nephrocyte diaphragm defects of an sns overexpression phenotype, pointing to genetic interaction of sns and c3g in nephrocytes. We also found that activated Nephrin recruited phosphorylated C3G and resulted in activation of Integrin β1 in cultured podocytes. CONCLUSIONS Our findings suggest that Nephrin can mediate a signaling pathway that results in activation of Integrin β1 at focal adhesions, which may affect podocyte attachment to the extracellular matrix.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | - Christian Klämbt
- Neurobiology, Westfälische-Wilhelms University Münster, Münster, Germany
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6
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Vukićević T, Hinze C, Baltzer S, Himmerkus N, Quintanova C, Zühlke K, Compton F, Ahlborn R, Dema A, Eichhorst J, Wiesner B, Bleich M, Schmidt-Ott KM, Klussmann E. Fluconazole Increases Osmotic Water Transport in Renal Collecting Duct through Effects on Aquaporin-2 Trafficking. J Am Soc Nephrol 2019; 30:795-810. [PMID: 30988011 DOI: 10.1681/asn.2018060668] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 02/13/2019] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Arginine-vasopressin (AVP) binding to vasopressin V2 receptors promotes redistribution of the water channel aquaporin-2 (AQP2) from intracellular vesicles into the plasma membrane of renal collecting duct principal cells. This pathway fine-tunes renal water reabsorption and urinary concentration, and its perturbation is associated with diabetes insipidus. Previously, we identified the antimycotic drug fluconazole as a potential modulator of AQP2 localization. METHODS We assessed the influence of fluconazole on AQP2 localization in vitro and in vivo as well as the drug's effects on AQP2 phosphorylation and RhoA (a small GTPase, which under resting conditions, maintains F-actin to block AQP2-bearing vesicles from reaching the plasma membrane). We also tested fluconazole's effects on water flow across epithelia of isolated mouse collecting ducts and on urine output in mice treated with tolvaptan, a VR2 blocker that causes a nephrogenic diabetes insipidus-like excessive loss of hypotonic urine. RESULTS Fluconazole increased plasma membrane localization of AQP2 in principal cells independent of AVP. It also led to an increased AQP2 abundance associated with alterations in phosphorylation status and ubiquitination as well as inhibition of RhoA. In isolated mouse collecting ducts, fluconazole increased transepithelial water reabsorption. In mice, fluconazole increased collecting duct AQP2 plasma membrane localization and reduced urinary output. Fluconazole also reduced urinary output in tolvaptan-treated mice. CONCLUSIONS Fluconazole promotes collecting duct AQP2 plasma membrane localization in the absence of AVP. Therefore, it might have utility in treating forms of diabetes insipidus (e.g., X-linked nephrogenic diabetes insipidus) in which the kidney responds inappropriately to AVP.
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Affiliation(s)
- Tanja Vukićević
- Max Delbrück Center for Molecular Medicine Berlin, (MDC), Research area Cardiovascular & Metabolic Disease, Berlin, Germany
| | - Christian Hinze
- Max Delbrück Center for Molecular Medicine Berlin, (MDC), Research area Cardiovascular & Metabolic Disease, Berlin, Germany.,Department of Nephrology and Medical Intensive Care and.,Berlin Institute of Health, Berlin, Germany
| | - Sandrine Baltzer
- Max Delbrück Center for Molecular Medicine Berlin, (MDC), Research area Cardiovascular & Metabolic Disease, Berlin, Germany
| | - Nina Himmerkus
- Institute of Physiology, Christian Albrechts University Kiel, Kiel, Germany
| | | | - Kerstin Zühlke
- Max Delbrück Center for Molecular Medicine Berlin, (MDC), Research area Cardiovascular & Metabolic Disease, Berlin, Germany
| | - Friederike Compton
- Department of Nephrology and Medical Intensive Care and.,Berlin Institute of Health, Berlin, Germany
| | - Robert Ahlborn
- Information Technology Department, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Alessandro Dema
- Max Delbrück Center for Molecular Medicine Berlin, (MDC), Research area Cardiovascular & Metabolic Disease, Berlin, Germany
| | - Jenny Eichhorst
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Cellular Imaging, Berlin, Germany
| | - Burkhard Wiesner
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Cellular Imaging, Berlin, Germany
| | - Markus Bleich
- Institute of Physiology, Christian Albrechts University Kiel, Kiel, Germany
| | - Kai M Schmidt-Ott
- Max Delbrück Center for Molecular Medicine Berlin, (MDC), Research area Cardiovascular & Metabolic Disease, Berlin, Germany; .,Department of Nephrology and Medical Intensive Care and.,Berlin Institute of Health, Berlin, Germany
| | - Enno Klussmann
- Max Delbrück Center for Molecular Medicine Berlin, (MDC), Research area Cardiovascular & Metabolic Disease, Berlin, Germany; .,German Centre for Cardiovascular Research (DZHK), Partner Site Berlin, Berlin, Germany; and.,Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Vegetative Physiology, Berlin, Germany
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7
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Fang W, Wang Z, Li Q, Wang X, Zhang Y, Sun Y, Tang W, Ma C, Sun J, Li N, Yi F. Gpr97 Exacerbates AKI by Mediating Sema3A Signaling. J Am Soc Nephrol 2018. [PMID: 29531097 DOI: 10.1681/asn.2017080932] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Background G protein-coupled receptors (GPCRs) participate in a variety of physiologic functions, and several GPCRs have critical physiologic and pathophysiologic roles in the regulation of renal function. We investigated the role of Gpr97, a newly identified member of the adhesion GPCR family, in AKI.Methods AKI was induced by ischemia-reperfusion or cisplatin treatment in Gpr97-deficient mice. We assessed renal injury in these models and in patients with acute tubular necrosis by histologic examination, and we conducted microarray analysis and in vitro assays to determine the molecular mechanisms of Gpr97 function.Results Gpr97 was upregulated in the kidneys from mice with AKI and patients with biopsy-proven acute tubular necrosis compared with healthy controls. In AKI models, Gpr97-deficient mice had significantly less renal injury and inflammation than wild-type mice. Gpr97 deficiency also attenuated the AKI-induced expression of semaphorin 3A (Sema3A), a potential early diagnostic biomarker of renal injury. In NRK-52E cells subjected to oxygen-glucose deprivation, siRNA-mediated knockdown of Gpr97 further increased the expression of survivin and phosphorylated STAT3 and reduced toll-like receptor 4 expression. Cotreatment with recombinant murine Sema3A protein counteracted these effects. Finally, additional in vivo and in vitro studies, including electrophoretic mobility shift assays and luciferase reporter assays, showed that Gpr97 deficiency attenuates ischemia-reperfusion-induced expression of the RNA-binding protein human antigen R, which post-transcriptionally regulates Sema3A expression.Conclusions Gpr97 is an important mediator of AKI, and pharmacologic targeting of Gpr97-mediated Sema3A signaling at multiple levels may provide a novel approach for the treatment of AKI.
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Affiliation(s)
| | | | | | | | | | - Yu Sun
- Departments of Pharmacology
| | | | | | - Jinpeng Sun
- Biochemistry and Molecular Biology, The Key Laboratory of Infection and Immunity of Shandong Province, School of Basic Medical Science, and
| | - Ningjun Li
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia
| | - Fan Yi
- Departments of Pharmacology, .,The State Key Laboratory of Microbial Technology, Shandong University, Jinan, China; and
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Hickmann L, Steglich A, Gerlach M, Al-Mekhlafi M, Sradnick J, Lachmann P, Sequeira-Lopez MLS, Gomez RA, Hohenstein B, Hugo C, Todorov VT. Persistent and inducible neogenesis repopulates progenitor renin lineage cells in the kidney. Kidney Int 2017; 92:1419-1432. [PMID: 28688581 DOI: 10.1016/j.kint.2017.04.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/23/2017] [Accepted: 04/06/2017] [Indexed: 10/19/2022]
Abstract
Renin lineage cells (RLCs) serve as a progenitor cell reservoir during nephrogenesis and after renal injury. The maintenance mechanisms of the RLC pool are still poorly understood. Since RLCs were also identified as a progenitor cell population in bone marrow we first considered that these may be their source in the kidney. However, transplantation experiments in adult mice demonstrated that bone marrow-derived cells do not give rise to RLCs in the kidney indicating their non-hematopoietic origin. Therefore we tested whether RLCs develop in the kidney through neogenesis (de novo differentiation) from cells that have never expressed renin before. We used a murine model to track neogenesis of RLCs by flow cytometry, histochemistry, and intravital kidney imaging. During nephrogenesis RLCs first appear at e14, form a distinct population at e16, and expand to reach a steady state level of 8-10% of all kidney cells in adulthood. De novo differentiated RLCs persist as a clearly detectable population through embryogenesis until at least eight months after birth. Pharmacologic stimulation of renin production with enalapril or glomerular injury induced the rate of RLC neogenesis in the adult mouse kidney by 14% or more than three-fold, respectively. Thus, the renal RLC niche is constantly filled by local de novo differentiation. This process could be stimulated consequently representing a new potential target to beneficially influence repair and regeneration after kidney injury.
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Affiliation(s)
- Linda Hickmann
- Experimental Nephrology and Division of Nephrology, Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Anne Steglich
- Experimental Nephrology and Division of Nephrology, Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Michael Gerlach
- Experimental Nephrology and Division of Nephrology, Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Moath Al-Mekhlafi
- Experimental Nephrology and Division of Nephrology, Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Jan Sradnick
- Experimental Nephrology and Division of Nephrology, Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Peter Lachmann
- Experimental Nephrology and Division of Nephrology, Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | | | - R Ariel Gomez
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Bernd Hohenstein
- Experimental Nephrology and Division of Nephrology, Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Christian Hugo
- Experimental Nephrology and Division of Nephrology, Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
| | - Vladimir T Todorov
- Experimental Nephrology and Division of Nephrology, Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
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9
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Zhu JY, Fu Y, Richman A, Zhao Z, Ray PE, Han Z. A Personalized Model of COQ2 Nephropathy Rescued by the Wild-Type COQ2 Allele or Dietary Coenzyme Q 10 Supplementation. J Am Soc Nephrol 2017; 28:2607-2617. [PMID: 28428331 DOI: 10.1681/asn.2016060626] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 03/09/2017] [Indexed: 12/26/2022] Open
Abstract
Clinical studies have identified patients with nephrotic syndrome caused by mutations in genes involved in the biosynthesis of coenzyme Q10 (CoQ10), a lipid component of the mitochondrial electron transport chain and an important antioxidant. However, the cellular mechanisms through which these mutations induce podocyte injury remain obscure. Here, we exploited the striking similarities between Drosophila nephrocytes and human podocytes to develop a Drosophila model of these renal diseases, and performed a systematic in vivo analysis assessing the role of CoQ10 pathway genes in renal function. Nephrocyte-specific silencing of Coq2, Coq6, and Coq8, which are genes involved in the CoQ10 pathway that have been associated with genetic nephrotic syndrome in humans, induced dramatic adverse changes in these cells. In particular, silencing of Coq2 led to an abnormal localization of slit diaphragms, collapse of lacunar channels, and more dysmorphic mitochondria. In addition, Coq2-deficient nephrocytes showed elevated levels of autophagy and mitophagy, increased levels of reactive oxygen species, and increased sensitivity to oxidative stress. Dietary supplementation with CoQ10 at least partially rescued these defects. Furthermore, expressing the wild-type human COQ2 gene specifically in nephrocytes rescued the defective protein uptake, but expressing the mutant allele derived from a patient with COQ2 nephropathy did not. We conclude that transgenic Drosophila lines carrying mutations in the CoQ10 pathway genes are clinically relevant models with which to explore the pathogenesis of podocyte injury and could serve as a new platform to test novel therapeutic approaches.
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Affiliation(s)
- Jun-Yi Zhu
- Centers for Cancer and Immunology Research and
| | - Yulong Fu
- Centers for Cancer and Immunology Research and
| | | | - Zhanzheng Zhao
- Department of Nephrology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China; and
| | - Patricio E Ray
- Genetic Medicine Research, Children's National Health System, Washington, DC.,Department of Pediatrics, The George Washington University School of Medicine and Health Sciences, Washington, DC
| | - Zhe Han
- Centers for Cancer and Immunology Research and .,Department of Pediatrics, The George Washington University School of Medicine and Health Sciences, Washington, DC
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10
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Melis N, Rubera I, Cougnon M, Giraud S, Mograbi B, Belaid A, Pisani DF, Huber SM, Lacas-Gervais S, Fragaki K, Blondeau N, Vigne P, Frelin C, Hauet T, Duranton C, Tauc M. Targeting eIF5A Hypusination Prevents Anoxic Cell Death through Mitochondrial Silencing and Improves Kidney Transplant Outcome. J Am Soc Nephrol 2017; 28:811-822. [PMID: 27612998 PMCID: PMC5328152 DOI: 10.1681/asn.2016010012] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 07/20/2016] [Indexed: 11/03/2022] Open
Abstract
The eukaryotic initiation factor 5A (eIF5A), which is highly conserved throughout evolution, has the unique characteristic of post-translational activation through hypusination. This modification is catalyzed by two enzymatic steps involving deoxyhypusine synthase (DHPS) and deoxyhypusine hydroxylase (DOHH). Notably, eIF5A may be involved in regulating the lifespan of Drosophila during long-term hypoxia. Therefore, we investigated the possibility of a link between eIF5A hypusination and cellular resistance to hypoxia/anoxia. Pharmacologic targeting of DHPS by N1-guanyl-1,7-diaminoheptane (GC7) or RNA interference-mediated inhibition of DHPS or DOHH induced tolerance to anoxia in immortalized mouse renal proximal cells. Furthermore, GC7 treatment of cells reversibly induced a metabolic shift toward glycolysis as well as mitochondrial remodeling and led to downregulated expression and activity of respiratory chain complexes, features characteristic of mitochondrial silencing. GC7 treatment also attenuated anoxia-induced generation of reactive oxygen species in these cells and in normoxic conditions, decreased the mitochondrial oxygen consumption rate of cultured cells and mice. In rats, intraperitoneal injection of GC7 substantially reduced renal levels of hypusinated eIF5A and protected against ischemia-reperfusion-induced renal injury. Finally, in the preclinical pig kidney transplant model, intravenous injection of GC7 before kidney removal significantly improved graft function recovery and late graft function and reduced interstitial fibrosis after transplant. This unconventional signaling pathway offers an innovative therapeutic target for treating hypoxic-ischemic human diseases and organ transplantation.
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Affiliation(s)
- Nicolas Melis
- Laboratoire de Physio-Médecine Moléculaire, Centre National de la Recherche Scientifique-UMR7370
| | - Isabelle Rubera
- Laboratoire de Physio-Médecine Moléculaire, Centre National de la Recherche Scientifique-UMR7370
| | - Marc Cougnon
- Laboratoire de Physio-Médecine Moléculaire, Centre National de la Recherche Scientifique-UMR7370
| | - Sébastien Giraud
- Centre Hospitalo Universitaire Poitiers, Service de Biochimie, Poitiers, France
- Institut National de la Santé et de la Recherche Médicale U1082 Ischémie Reperfusion en Transplantation d'Organes Mécanismes et Innovations Thérapeutiques, Poitiers, France
- Faculté de Médecine et de Pharmacie, Université de Poitiers, Poitiers, France; and
| | - Baharia Mograbi
- Institut de Recherche sur le Cancer, Centre National de la Recherche Scientifique-UMR7284, Institut National de la Santé et de la Recherche Médicale U1081
| | - Amine Belaid
- Institut de Recherche sur le Cancer, Centre National de la Recherche Scientifique-UMR7284, Institut National de la Santé et de la Recherche Médicale U1081
| | - Didier F Pisani
- Institute of Biology Valrose, Centre National de la Recherche Scientifique-UMR7277 Institut National de la Santé et de la Recherche Médicale U1091
| | - Stephan M Huber
- Department of Radiation Oncology, University of Tübingen, Tuebingen, Germany
| | | | - Konstantina Fragaki
- Institut de Recherche sur le Cancer, Centre National de la Recherche Scientifique-UMR7284, Institut National de la Santé et de la Recherche Médicale U1081
| | - Nicolas Blondeau
- Institut de Physiologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique Unité Mixte de Recherche UMR7275, University Nice-Sophia Antipolis, Nice, France
| | - Paul Vigne
- Institute of Biology Valrose, Centre National de la Recherche Scientifique-UMR7277 Institut National de la Santé et de la Recherche Médicale U1091
| | - Christian Frelin
- Institute of Biology Valrose, Centre National de la Recherche Scientifique-UMR7277 Institut National de la Santé et de la Recherche Médicale U1091
| | - Thierry Hauet
- Centre Hospitalo Universitaire Poitiers, Service de Biochimie, Poitiers, France
- Institut National de la Santé et de la Recherche Médicale U1082 Ischémie Reperfusion en Transplantation d'Organes Mécanismes et Innovations Thérapeutiques, Poitiers, France
- Faculté de Médecine et de Pharmacie, Université de Poitiers, Poitiers, France; and
| | - Christophe Duranton
- Laboratoire de Physio-Médecine Moléculaire, Centre National de la Recherche Scientifique-UMR7370
| | - Michel Tauc
- Laboratoire de Physio-Médecine Moléculaire, Centre National de la Recherche Scientifique-UMR7370,
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11
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Bohnenpoll T, Feraric S, Nattkemper M, Weiss AC, Rudat C, Meuser M, Trowe MO, Kispert A. Diversification of Cell Lineages in Ureter Development. J Am Soc Nephrol 2016; 28:1792-1801. [PMID: 28028137 DOI: 10.1681/asn.2016080849] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 11/08/2016] [Indexed: 02/06/2023] Open
Abstract
The mammalian ureter consists of a mesenchymal wall composed of smooth muscle cells and surrounding fibrocytes of the tunica adventitia and the lamina propria and an inner epithelial lining composed of layers of basal, intermediate, and superficial cells. How these cell types arise from multipotent progenitors is poorly understood. Here, we performed marker analysis, cell proliferation assays, and genetic lineage tracing to define the lineage relations and restrictions of the mesenchymal and epithelial cell types in the developing and mature mouse ureter. At embryonic day (E) 12.5, the mesenchymal precursor pool began to subdivide into an inner and outer compartment that began to express markers of smooth muscle precursors and adventitial fibrocytes, respectively, by E13.5. Smooth muscle precursors further diversified into lamina propria cells directly adjacent to the ureteric epithelium and differentiated smooth muscle cells from E16.5 onwards. Uncommitted epithelial progenitors of the ureter differentiated into intermediate cells at E14.5. After stratification into two layers at E15.5 and three cell layers at E18.5, intermediate cells differentiated into basal cells and superficial cells. In homeostasis, proliferation of all epithelial and mesenchymal cell types remained low but intermediate cells still gave rise to basal cells, whereas basal cells divided only into basal cells. These studies provide a framework to further determine the molecular mechanisms of cell differentiation in the tissues of the developing ureter.
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Affiliation(s)
- Tobias Bohnenpoll
- Institut für Molekularbiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Sarah Feraric
- Institut für Molekularbiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Marvin Nattkemper
- Institut für Molekularbiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Anna-Carina Weiss
- Institut für Molekularbiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Carsten Rudat
- Institut für Molekularbiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Max Meuser
- Institut für Molekularbiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Mark-Oliver Trowe
- Institut für Molekularbiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Andreas Kispert
- Institut für Molekularbiologie, Medizinische Hochschule Hannover, Hannover, Germany
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12
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Yao Y, Wang J, Yoshida S, Nada S, Okada M, Inoki K. Role of Ragulator in the Regulation of Mechanistic Target of Rapamycin Signaling in Podocytes and Glomerular Function. J Am Soc Nephrol 2016; 27:3653-3665. [PMID: 27032892 DOI: 10.1681/asn.2015010032] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 02/17/2016] [Indexed: 02/03/2023] Open
Abstract
Aberrant activation of mechanistic target of rapamycin complex 1 (mTORC1) in glomerular podocytes leads to glomerular insufficiency and may contribute to the development of glomerular diseases, including diabetic nephropathy. Thus, an approach for preventing mTORC1 activation may allow circumvention of the onset and progression of mTORC1-dependent podocyte injury and glomerular diseases. mTORC1 activation requires inputs from both growth factors and nutrients that inactivate the tuberous sclerosis complex (TSC), a key suppressor of mTORC1, on the lysosome. Previous studies in mice revealed that the growth factor-phosphatidylinositol 3-kinase pathway and mTORC1 are essential for maintaining normal podocyte function, suggesting that direct inhibition of the phosphatidylinositol 3-kinase pathway or mTORC1 may not be an ideal approach to sustaining physiologic podocyte functions under certain disease conditions. Here, we report the role of the Ragulator complex, which recruits mTORC1 to lysosomes in response to nutrient availability in podocytes. Notably, podocytes lacking Ragulator maintain basal mTORC1 activity. Unlike podocyte-specific mTORC1-knockout mice, mice lacking functional Ragulator in podocytes did not show abnormalities in podocyte or glomerular function. However, aberrant mTORC1 activation induced by active Rheb in podocyte-specific TSC1-knockout (podo-TSC1 KO) mice did require Ragulator. Moreover, ablation of Ragulator in the podocytes of podo-TSC1 KO mice or streptozotocin-induced diabetic mice significantly blocked the development of pathologic renal phenotypes. These observations suggest that the blockade of mTORC1 recruitment to lysosomes may be a useful clinical approach to attenuate aberrant mTORC1 activation under certain disease conditions.
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Affiliation(s)
| | | | - Sei Yoshida
- Life Sciences Institute.,Department of Microbiology and Immunology
| | - Shigeyuki Nada
- Department of Oncogene Research, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Masato Okada
- Department of Oncogene Research, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Ken Inoki
- Life Sciences Institute, .,Department of Molecular and Integrative Physiology, and.,Department of Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan; and
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13
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Mami I, Bouvier N, El Karoui K, Gallazzini M, Rabant M, Laurent-Puig P, Li S, Tharaux PL, Beaune P, Thervet E, Chevet E, Hu GF, Pallet N. Angiogenin Mediates Cell-Autonomous Translational Control under Endoplasmic Reticulum Stress and Attenuates Kidney Injury. J Am Soc Nephrol 2015. [PMID: 26195817 DOI: 10.1681/asn.2015020196] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Endoplasmic reticulum (ER) stress is involved in the pathophysiology of kidney disease and aging, but the molecular bases underlying the biologic outcomes on the evolution of renal disease remain mostly unknown. Angiogenin (ANG) is a ribonuclease that promotes cellular adaptation under stress but its contribution to ER stress signaling remains elusive. In this study, we investigated the ANG-mediated contribution to the signaling and biologic outcomes of ER stress in kidney injury. ANG expression was significantly higher in samples from injured human kidneys than in samples from normal human kidneys, and in mouse and rat kidneys, ANG expression was specifically induced under ER stress. In human renal epithelial cells, ER stress induced ANG expression in a manner dependent on the activity of transcription factor XBP1, and ANG promoted cellular adaptation to ER stress through induction of stress granules and inhibition of translation. Moreover, the severity of renal lesions induced by ER stress was dramatically greater in ANG knockout mice (Ang(-/-)) mice than in wild-type mice. These results indicate that ANG is a critical mediator of tissue adaptation to kidney injury and reveal a physiologically relevant ER stress-mediated adaptive translational control mechanism.
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Affiliation(s)
- Iadh Mami
- Institut National de la Sante et de la Recherche Médicale (INSERM) U1147, Saints-Pères Research Center Paris, France; Paris Descartes University Paris, France
| | | | - Khalil El Karoui
- Paris Descartes University Paris, France; INSERM U1151, Sick Childrens Necker Institute Paris, France
| | - Morgan Gallazzini
- Paris Descartes University Paris, France; INSERM U1151, Sick Childrens Necker Institute Paris, France
| | - Marion Rabant
- Paris Descartes University Paris, France; Pathology Department, Necker Hospital Paris, France
| | - Pierre Laurent-Puig
- Institut National de la Sante et de la Recherche Médicale (INSERM) U1147, Saints-Pères Research Center Paris, France; Paris Descartes University Paris, France; Clinical Chemistry and
| | - Shuping Li
- Molecular Oncology Research Institute, Tufts Medical Center, Boston, Massachusetts
| | | | - Philippe Beaune
- Institut National de la Sante et de la Recherche Médicale (INSERM) U1147, Saints-Pères Research Center Paris, France; Paris Descartes University Paris, France; Clinical Chemistry and
| | - Eric Thervet
- Paris Descartes University Paris, France; Nephrology Departments, Georges Pompidou European Hospital Paris, France
| | - Eric Chevet
- INSERM, UMR-U1053, Team Endoplasmic Reticulum Stress and Cancer, Bordeaux, France
| | - Guo-Fu Hu
- Molecular Oncology Research Institute, Tufts Medical Center, Boston, Massachusetts
| | - Nicolas Pallet
- Institut National de la Sante et de la Recherche Médicale (INSERM) U1147, Saints-Pères Research Center Paris, France; Paris Descartes University Paris, France; Clinical Chemistry and Nephrology Departments, Georges Pompidou European Hospital Paris, France;
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14
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Han SH, Malaga-Dieguez L, Chinga F, Kang HM, Tao J, Reidy K, Susztak K. Deletion of Lkb1 in Renal Tubular Epithelial Cells Leads to CKD by Altering Metabolism. J Am Soc Nephrol 2015; 27:439-53. [PMID: 26054542 DOI: 10.1681/asn.2014121181] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 04/12/2015] [Indexed: 12/30/2022] Open
Abstract
Renal tubule epithelial cells are high-energy demanding polarized epithelial cells. Liver kinase B1 (LKB1) is a key regulator of polarity, proliferation, and cell metabolism in epithelial cells, but the function of LKB1 in the kidney is unclear. Our unbiased gene expression studies of human control and CKD kidney samples identified lower expression of LKB1 and regulatory proteins in CKD. Mice with distal tubule epithelial-specific Lkb1 deletion (Ksp-Cre/Lkb1(flox/flox)) exhibited progressive kidney disease characterized by flattened dedifferentiated tubule epithelial cells, interstitial matrix accumulation, and dilated cystic-appearing tubules. Expression of epithelial polarity markers β-catenin and E-cadherin was not altered even at later stages. However, expression levels of key regulators of metabolism, AMP-activated protein kinase (Ampk), peroxisome proliferative activated receptor gamma coactivator 1-α (Ppargc1a), and Ppara, were significantly lower than those in controls and correlated with fibrosis development. Loss of Lkb1 in cultured epithelial cells resulted in energy depletion, apoptosis, less fatty acid oxidation and glycolysis, and a profibrotic phenotype. Treatment of Lkb1-deficient cells with an AMP-activated protein kinase (AMPK) agonist (A769662) or a peroxisome proliferative activated receptor alpha agonist (fenofibrate) restored the fatty oxidation defect and reduced apoptosis. In conclusion, we show that loss of LKB1 in renal tubular epithelial cells has an important role in kidney disease development by influencing intracellular metabolism.
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Affiliation(s)
- Seung Hyeok Han
- Renal Electrolyte and Hypertension Division, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Laura Malaga-Dieguez
- Renal Electrolyte and Hypertension Division, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Frank Chinga
- Renal Electrolyte and Hypertension Division, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Hyun Mi Kang
- Renal Electrolyte and Hypertension Division, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jianling Tao
- Renal Electrolyte and Hypertension Division, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Division of Nephrology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Kimberly Reidy
- Renal Electrolyte and Hypertension Division, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, New York; and
| | - Katalin Susztak
- Renal Electrolyte and Hypertension Division, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania;
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15
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Dere R, Perkins AL, Bawa-Khalfe T, Jonasch D, Walker CL. β-catenin links von Hippel-Lindau to aurora kinase A and loss of primary cilia in renal cell carcinoma. J Am Soc Nephrol 2014; 26:553-64. [PMID: 25313256 DOI: 10.1681/asn.2013090984] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
von Hippel-Lindau (VHL) gene mutations are associated with clear cell renal cell carcinoma (ccRCC). A hallmark of ccRCC is loss of the primary cilium. Loss of this key organelle in ccRCC is caused by loss of VHL and associated with increased Aurora kinase A (AURKA) and histone deacetylase 6 (HDAC6) activities, which drive disassembly of the primary cilium. However, the underlying mechanism by which VHL loss increases AURKA levels has not been clearly elucidated, although it has been suggested that hypoxia-inducible factor-1α (HIF-1α) mediates increased AURKA expression in VHL-null cells. By contrast, we found that elevated AURKA expression is not increased by HIF-1α, suggesting an alternate mechanism for AURKA dysregulation in VHL-null cells. We report here that AURKA expression is driven by β-catenin transcription in VHL-null cells. In a panel of RCC cell lines, we observed nuclear accumulation of β-catenin and increased AURKA signaling to HDAC6. Moreover, HIF-1α inhibited AURKA expression by inhibiting β-catenin transcription. VHL knockdown activated β-catenin and elevated AURKA expression, decreased primary cilia formation, and caused significant shortening of cilia length in cells that did form cilia. The β-catenin responsive transcription inhibitor iCRT14 reduced AURKA levels and rescued ciliary defects, inducing a significant increase in primary cilia formation in VHL-deficient cells. These data define a role for β-catenin in regulating AURKA and formation of primary cilia in the setting of VHL deficiency, opening new avenues for treatment with β-catenin inhibitors to rescue ciliogenesis in ccRCC.
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Affiliation(s)
- Ruhee Dere
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, Texas; and
| | - Ashley Lyn Perkins
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, Texas; and
| | - Tasneem Bawa-Khalfe
- Department of Cardiology, University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Darius Jonasch
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, Texas; and
| | - Cheryl Lyn Walker
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, Texas; and
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16
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Abstract
Renal epithelial cells must maintain distinct protein compositions in their apical and basolateral membranes in order to perform their transport functions. The creation of these polarized protein distributions depends on sorting signals that designate the trafficking route and site of ultimate functional residence for each protein. Segregation of newly synthesized apical and basolateral proteins into distinct carrier vesicles can occur at the trans-Golgi network, recycling endosomes, or a growing assortment of stations along the cellular trafficking pathway. The nature of the specific sorting signal and the mechanism through which it is interpreted can influence the route a protein takes through the cell. Cell type-specific variations in the targeting motifs of a protein, as are evident for Na,K-ATPase, demonstrate a remarkable capacity to adapt sorting pathways to different developmental states or physiologic requirements. This review summarizes our current understanding of apical and basolateral trafficking routes in polarized epithelial cells.
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Affiliation(s)
- Emily H Stoops
- Departments of Cellular & Molecular Physiology and Cell Biology, Yale University School of Medicine, New Haven, Connecticut
| | - Michael J Caplan
- Departments of Cellular & Molecular Physiology and Cell Biology, Yale University School of Medicine, New Haven, Connecticut
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