1
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Haydak J, Azeloglu EU. Role of biophysics and mechanobiology in podocyte physiology. Nat Rev Nephrol 2024; 20:371-385. [PMID: 38443711 DOI: 10.1038/s41581-024-00815-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2024] [Indexed: 03/07/2024]
Abstract
Podocytes form the backbone of the glomerular filtration barrier and are exposed to various mechanical forces throughout the lifetime of an individual. The highly dynamic biomechanical environment of the glomerular capillaries greatly influences the cell biology of podocytes and their pathophysiology. Throughout the past two decades, a holistic picture of podocyte cell biology has emerged, highlighting mechanobiological signalling pathways, cytoskeletal dynamics and cellular adhesion as key determinants of biomechanical resilience in podocytes. This biomechanical resilience is essential for the physiological function of podocytes, including the formation and maintenance of the glomerular filtration barrier. Podocytes integrate diverse biomechanical stimuli from their environment and adapt their biophysical properties accordingly. However, perturbations in biomechanical cues or the underlying podocyte mechanobiology can lead to glomerular dysfunction with severe clinical consequences, including proteinuria and glomerulosclerosis. As our mechanistic understanding of podocyte mechanobiology and its role in the pathogenesis of glomerular disease increases, new targets for podocyte-specific therapeutics will emerge. Treating glomerular diseases by targeting podocyte mechanobiology might improve therapeutic precision and efficacy, with potential to reduce the burden of chronic kidney disease on individuals and health-care systems alike.
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Affiliation(s)
- Jonathan Haydak
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Evren U Azeloglu
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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2
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Liu PJ, Sayeeda K, Zhuang C, Krendel M. Roles of myosin 1e and the actin cytoskeleton in kidney functions and familial kidney disease. Cytoskeleton (Hoboken) 2024. [PMID: 38708443 DOI: 10.1002/cm.21861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/21/2024] [Accepted: 04/04/2024] [Indexed: 05/07/2024]
Abstract
Mammalian kidneys are responsible for removing metabolic waste and maintaining fluid and electrolyte homeostasis via selective filtration. One of the proteins closely linked to selective renal filtration is myosin 1e (Myo1e), an actin-dependent molecular motor found in the specialized kidney epithelial cells involved in the assembly and maintenance of the renal filter. Point mutations in the gene encoding Myo1e, MYO1E, have been linked to familial kidney disease, and Myo1e knockout in mice leads to the disruption of selective filtration. In this review, we discuss the role of the actin cytoskeleton in renal filtration, the known and hypothesized functions of Myo1e, and the possible explanations for the impact of MYO1E mutations on renal function.
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Affiliation(s)
- Pei-Ju Liu
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Kazi Sayeeda
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Cindy Zhuang
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Mira Krendel
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
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3
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Wang Y, Peng L, Lu X, Zhang H, Zhao H, Zhao T, Yang L, Mao H, Ma F, Liu T, Li P, Zhan Y. Tangshen formula protects against podocyte apoptosis via enhancing the TFEB-mediated autophagy-lysosome pathway in diabetic nephropathy. JOURNAL OF ETHNOPHARMACOLOGY 2024; 324:117721. [PMID: 38199335 DOI: 10.1016/j.jep.2024.117721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 12/28/2023] [Accepted: 01/04/2024] [Indexed: 01/12/2024]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Diabetic nephropathy (DN) is the leading cause of end-stage kidney disease and currently there are no specific and effective drugs for its treatment. Podocyte injury is a detrimental feature and the major cause of albuminuria in DN. We previously reported Tangshen Formula (TSF), a Chinese herbal medicine, has shown therapeutic effects on DN. However, the underlying mechanisms remain obscure. AIM OF THE STUDY This study aimed to explore the protective effect of TSF on podocyte apoptosis in DN and elucidate the potential mechanism. MATERIALS AND METHODS The effects of TSF were assessed in a murine model using male KKAy diabetic mice, as well as in advanced glycation end products-stimulated primary mice podocytes. Transcription factor EB (TFEB) knockdown primary podocytes were employed for mechanistic studies. In vivo and in vitro studies were performed and results assessed using transmission electron microscopy, immunofluorescence staining, and western blotting. RESULTS TSF treatment alleviated podocyte apoptosis and structural impairment, decreased albuminuria, and mitigated renal dysfunction in KKAy mice. Notably, TSF extracted twice showed a more significant reduction in proteinuria than TSF extracted three times. Accumulation of autophagic biomarkers p62 and LC3, and aberrant autophagic flux in podocytes of DN mice were significantly altered by TSF therapy. Consistent with the in vivo results, TSF prevented the apoptosis of primary podocytes exposed to AGEs and activated autophagy. However, the anti-apoptosis capacity of TSF was countered by the autophagy-lysosome inhibitor chloroquine. We found that TSF increased the nuclear translocation of TFEB in diabetic podocytes, and thus upregulated transcription of its several autophagic target genes. Pharmacological activation of TFEB by TSF accelerated the conversion of autophagosome to autolysosome and lysosomal biogenesis, further augmented autophagic flux. Conversely, TFEB knockdown negated the favorable effects of TSF on autophagy in AGEs-stimulated primary podocytes. CONCLUSIONS These findings indicate TSF appears to attenuate podocyte apoptosis and promote autophagy in DN via the TFEB-mediated autophagy-lysosome system. Thus, TSF may be a therapeutic candidate for DN.
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Affiliation(s)
- Yuyang Wang
- Department of Nephrology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
| | - Liang Peng
- Beijing Key Laboratory for Immune-Mediated Inflammatory Diseases, Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, China.
| | - Xiaoguang Lu
- Department of Nephrology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
| | - Haojun Zhang
- Beijing Key Laboratory for Immune-Mediated Inflammatory Diseases, Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, China.
| | - Hailing Zhao
- Beijing Key Laboratory for Immune-Mediated Inflammatory Diseases, Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, China.
| | - Tingting Zhao
- Beijing Key Laboratory for Immune-Mediated Inflammatory Diseases, Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, China.
| | - Liping Yang
- Department of Nephrology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
| | - Huimin Mao
- Department of Nephrology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
| | - Fang Ma
- Department of Nephrology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
| | - Tongtong Liu
- Department of Nephrology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
| | - Ping Li
- Beijing Key Laboratory for Immune-Mediated Inflammatory Diseases, Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, China.
| | - Yongli Zhan
- Department of Nephrology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
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4
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Saito K, Yokawa S, Kurihara H, Yaoita E, Mizuta S, Tada K, Oda M, Hatakeyama H, Ohta Y. FilGAP controls cell-extracellular matrix adhesion and process formation of kidney podocytes. FASEB J 2024; 38:e23504. [PMID: 38421271 DOI: 10.1096/fj.202301691rr] [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: 08/21/2023] [Revised: 01/17/2024] [Accepted: 02/07/2024] [Indexed: 03/02/2024]
Abstract
The function of kidney podocytes is closely associated with actin cytoskeleton regulated by Rho small GTPases. Loss of actin-driven cell adhesions and processes is connected to podocyte dysfunction, proteinuria, and kidney diseases. FilGAP, a GTPase-activating protein for Rho small GTPase Rac1, is abundantly expressed in kidney podocytes, and its gene is linked to diseases in a family with focal segmental glomerulosclerosis. In this study, we have studied the role of FilGAP in podocytes in vitro. Depletion of FilGAP in cultured podocytes induced loss of actin stress fibers and increased Rac1 activity. Conversely, forced expression of FilGAP increased stress fiber formation whereas Rac1 activation significantly reduced its formation. FilGAP localizes at the focal adhesion (FA), an integrin-based protein complex closely associated with stress fibers, that mediates cell-extracellular matrix (ECM) adhesion, and FilGAP depletion decreased FA formation and impaired attachment to the ECM. Moreover, in unique podocyte cell cultures capable of inducing the formation of highly organized processes including major processes and foot process-like projections, FilGAP depletion or Rac1 activation decreased the formation of these processes. The reduction of FAs and process formations in FilGAP-depleted podocyte cells was rescued by inhibition of Rac1 or P21-activated kinase 1 (PAK1), a downstream effector of Rac1, and PAK1 activation inhibited their formations. Thus, FilGAP contributes to both cell-ECM adhesion and process formation of podocytes by suppressing Rac1/PAK1 signaling.
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Affiliation(s)
- Koji Saito
- Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, Sagamihara, Kanagawa, Japan
| | - Seiji Yokawa
- Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, Sagamihara, Kanagawa, Japan
| | - Hidetake Kurihara
- Department of Physical Therapy, Faculty of Health Sciences, Aino University, Osaka, Ibaraki, Japan
| | - Eishin Yaoita
- Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Niigata, Japan
| | - Sari Mizuta
- Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, Sagamihara, Kanagawa, Japan
| | - Kanae Tada
- Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, Sagamihara, Kanagawa, Japan
| | - Moemi Oda
- Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, Sagamihara, Kanagawa, Japan
| | - Hiroyasu Hatakeyama
- Department of Physiology, School of Medicine, Kitasato University, Sagamihara, Kanagawa, Japan
| | - Yasutaka Ohta
- Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, Sagamihara, Kanagawa, Japan
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5
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Wang Y, Huang H, Weng H, Jia C, Liao B, Long Y, Yu F, Nie Y. Talin mechanotransduction in disease. Int J Biochem Cell Biol 2024; 166:106490. [PMID: 37914021 DOI: 10.1016/j.biocel.2023.106490] [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: 07/29/2023] [Revised: 10/26/2023] [Accepted: 10/26/2023] [Indexed: 11/03/2023]
Abstract
Talin protein (Talin 1/2) is a mechanosensitive cytoskeleton protein. The unique structure of the Talin plays a vital role in transmitting mechanical forces. Talin proteins connect the extracellular matrix to the cytoskeleton by linking to integrins and actin, thereby mediating the conversion of mechanical signals into biochemical signals and influencing disease progression as potential diagnostic indicators, therapeutic targets, and prognostic indicators of various diseases. Most studies in recent years have confirmed that mechanical forces also have a crucial role in the development of disease, and Talin has been found to play a role in several diseases. Still, more studies need to be done on how Talin is involved in mechanical signaling in disease. This review focuses on the mechanical signaling of Talin in disease, aiming to summarize the mechanisms by which Talin plays a role in disease and to provide references for further studies.
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Affiliation(s)
- Yingzi Wang
- Department of Cardiovascular Surgery, The Affiliated Hospital of Southwest Medical University, China
| | - Haozhong Huang
- Department of Cardiovascular Surgery, The Affiliated Hospital of Southwest Medical University, China
| | - Huimin Weng
- Department of Cardiovascular Surgery, The Affiliated Hospital of Southwest Medical University, China
| | - Chunsen Jia
- Department of Cardiovascular Surgery, The Affiliated Hospital of Southwest Medical University, China
| | - Bin Liao
- Department of Cardiovascular Surgery, The Affiliated Hospital of Southwest Medical University, China; Metabolic Vascular Disease Key Laboratory of Sichuan Province, China; Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, China; Key Laboratory of Cardiovascular Remodeling and Dysfunction, Luzhou, China
| | - Yang Long
- Department of Endocrinology and Metabolism, The Affiliated Hospital of Southwest Medical University, Luzhou, China; Metabolic Vascular Disease Key Laboratory of Sichuan Province, Luzhou, China; Sichuan Clinical Research Center for Nephropathy, Luzhou, China
| | - Fengxu Yu
- Department of Cardiovascular Surgery, The Affiliated Hospital of Southwest Medical University, China; Metabolic Vascular Disease Key Laboratory of Sichuan Province, China; Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, China; Key Laboratory of Cardiovascular Remodeling and Dysfunction, Luzhou, China
| | - Yongmei Nie
- Department of Cardiovascular Surgery, The Affiliated Hospital of Southwest Medical University, China; Metabolic Vascular Disease Key Laboratory of Sichuan Province, China; Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, China; Key Laboratory of Cardiovascular Remodeling and Dysfunction, Luzhou, China.
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6
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Cybulsky AV, Papillon J, Bryan C, Navarro‐Betancourt JR, Sabourin LA. Role of the Ste20-like kinase SLK in podocyte adhesion. Physiol Rep 2024; 12:e15897. [PMID: 38163671 PMCID: PMC10758337 DOI: 10.14814/phy2.15897] [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: 10/13/2023] [Revised: 11/16/2023] [Accepted: 11/16/2023] [Indexed: 01/03/2024] Open
Abstract
SLK controls the cytoskeleton, cell adhesion, and migration. Podocyte-specific deletion of SLK in mice leads to podocyte injury as mice age and exacerbates injury in experimental focal segment glomerulosclerosis (FSGS; adriamycin nephrosis). We hypothesized that adhesion proteins may be substrates of SLK. In adriamycin nephrosis, podocyte ultrastructural injury was exaggerated by SLK deletion. Analysis of a protein kinase phosphorylation site dataset showed that podocyte adhesion proteins-paxillin, vinculin, and talin-1 may be potential SLK substrates. In cultured podocytes, deletion of SLK increased adhesion to collagen. Analysis of paxillin, vinculin, and talin-1 showed that SLK deletion reduced focal adhesion complexes (FACs) containing these proteins mainly in adriamycin-induced injury; there was no change in FAC turnover (focal adhesion kinase Y397 phosphorylation). In podocytes, paxillin S250 showed basal phosphorylation that was slightly enhanced by SLK; however, SLK did not phosphorylate talin-1. In adriamycin nephrosis, SLK deletion did not alter glomerular expression/localization of talin-1 and vinculin, but increased focal adhesion kinase phosphorylation modestly. Therefore, SLK decreases podocyte adhesion, but FAC proteins in podocytes are not major substrates of SLK in health and disease.
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Affiliation(s)
- Andrey V. Cybulsky
- Department of MedicineMcGill University Health Centre Research Institute, McGill UniversityMontrealQuebecCanada
| | - Joan Papillon
- Department of MedicineMcGill University Health Centre Research Institute, McGill UniversityMontrealQuebecCanada
| | - Craig Bryan
- Department of MedicineMcGill University Health Centre Research Institute, McGill UniversityMontrealQuebecCanada
| | - José R. Navarro‐Betancourt
- Department of MedicineMcGill University Health Centre Research Institute, McGill UniversityMontrealQuebecCanada
| | - Luc A. Sabourin
- Ottawa Hospital Research Institute, Cancer TherapeuticsOttawaOntarioCanada
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7
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Tian X, Pedigo CE, Li K, Ma X, Bunda P, Pell J, Lek A, Gu J, Zhang Y, Medina Rangel PX, Li W, Schwartze E, Nagata S, Lerner G, Perincheri S, Priyadarshini A, Zhao H, Lek M, Menon MC, Fu R, Ishibe S. Profilin1 is required for prevention of mitotic catastrophe in murine and human glomerular diseases. J Clin Invest 2023; 133:e171237. [PMID: 37847555 PMCID: PMC10721156 DOI: 10.1172/jci171237] [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: 04/05/2023] [Accepted: 10/12/2023] [Indexed: 10/18/2023] Open
Abstract
The progression of proteinuric kidney diseases is associated with podocyte loss, but the mechanisms underlying this process remain unclear. Podocytes reenter the cell cycle to repair double-stranded DNA breaks. However, unsuccessful repair can result in podocytes crossing the G1/S checkpoint and undergoing abortive cytokinesis. In this study, we identified Pfn1 as indispensable in maintaining glomerular integrity - its tissue-specific loss in mouse podocytes resulted in severe proteinuria and kidney failure. Our results suggest that this phenotype is due to podocyte mitotic catastrophe (MC), characterized histologically and ultrastructurally by abundant multinucleated cells, irregular nuclei, and mitotic spindles. Podocyte cell cycle reentry was identified using FUCCI2aR mice, and we observed altered expression of cell-cycle associated proteins, such as p21, p53, cyclin B1, and cyclin D1. Podocyte-specific translating ribosome affinity purification and RNA-Seq revealed the downregulation of ribosomal RNA-processing 8 (Rrp8). Overexpression of Rrp8 in Pfn1-KO podocytes partially rescued the phenotype in vitro. Clinical and ultrastructural tomographic analysis of patients with diverse proteinuric kidney diseases further validated the presence of MC podocytes and reduction in podocyte PFN1 expression within kidney tissues. These results suggest that profilin1 is essential in regulating the podocyte cell cycle and its disruption leads to MC and subsequent podocyte loss.
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Affiliation(s)
- Xuefei Tian
- Section of Nephrology, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Christopher E. Pedigo
- Section of Nephrology, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Ke Li
- Department of Nephrology, Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Xiaotao Ma
- Department of Nephrology, Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Patricia Bunda
- Section of Nephrology, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - John Pell
- Section of Nephrology, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | | | - Jianlei Gu
- Department of Biostatistics, Yale School of Public Health, New Haven, Connecticut, USA
| | - Yan Zhang
- Bioinformation Department, Suzhou SITRI Institute of Immunology Co. Ltd., Suzhou, Jiangsu, China
| | - Paulina X. Medina Rangel
- Section of Nephrology, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Wei Li
- Section of Nephrology, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Eike Schwartze
- Section of Nephrology, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Soichiro Nagata
- Section of Nephrology, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Gabriel Lerner
- Departments of Surgical Pathology and Laboratory Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Sudhir Perincheri
- Departments of Surgical Pathology and Laboratory Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Anupama Priyadarshini
- Section of Nephrology, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Hongyu Zhao
- Department of Biostatistics, Yale School of Public Health, New Haven, Connecticut, USA
| | | | - Madhav C. Menon
- Section of Nephrology, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Rongguo Fu
- Department of Nephrology, Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Shuta Ishibe
- Section of Nephrology, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
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8
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Salemkour Y, Yildiz D, Dionet L, ‘t Hart DC, Verheijden KA, Saito R, Mahtal N, Delbet JD, Letavernier E, Rabant M, Karras A, van der Vlag J, Nijenhuis T, Tharaux PL, Lenoir O. Podocyte Injury in Diabetic Kidney Disease in Mouse Models Involves TRPC6-mediated Calpain Activation Impairing Autophagy. J Am Soc Nephrol 2023; 34:1823-1842. [PMID: 37678257 PMCID: PMC10631601 DOI: 10.1681/asn.0000000000000212] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 07/28/2023] [Indexed: 09/09/2023] Open
Abstract
SIGNIFICANCE STATEMENT Autophagy protects podocytes from injury in diabetic kidney disease (DKD). Restoring glomerular autophagy is a promising approach to limit DKD. This study demonstrates a novel regulatory mechanism of autophagy that blocks this critical protection of the glomerular filtration barrier. We demonstrated that TRPC6 induced in podocytes in mouse models of diabetes mediates calpain activation, thereby impairing podocyte autophagy, causing injury and accelerating DKD. Furthermore, this study provides proof of principle for druggable targets for DKD because restoration of podocyte autophagy by calpain inhibitors effectively limits glomerular destruction. BACKGROUND Diabetic kidney disease is associated with impaired podocyte autophagy and subsequent podocyte injury. The regulation of podocyte autophagy is unique because it minimally uses the mTOR and AMPK pathways. Thus, the molecular mechanisms underlying the impaired autophagy in podocytes in diabetic kidney disease remain largely elusive. METHODS This study investigated how the calcium channel TRPC6 and the cysteine protease calpains deleteriously affect podocyte autophagy in diabetic kidney disease in mice. We demonstrated that TRPC6 knockdown in podocytes increased the autophagic flux because of decreased cysteine protease calpain activity. Diabetic kidney disease was induced in vivo using streptozotocin with unilateral nephrectomy and the BTBR ob/ob mouse models. RESULTS Diabetes increased TRPC6 expression in podocytes in vivo with decreased podocyte autophagic flux. Transgenic overexpression of the endogenous calpain inhibitor calpastatin, as well as pharmacologic inhibition of calpain activity, normalized podocyte autophagic flux, reduced nephrin loss, and prevented the development of albuminuria in diabetic mice. In kidney biopsies from patients with diabetes, we further confirmed that TRPC6 overexpression in podocytes correlates with decreased calpastatin expression, autophagy blockade, and podocyte injury. CONCLUSIONS Overall, we discovered a new mechanism that connects TRPC6 and calpain activity to impaired podocyte autophagy, increased podocyte injury, and development of proteinuria in the context of diabetic kidney disease. Therefore, targeting TRPC6 and/or calpain to restore podocyte autophagy might be a promising therapeutic strategy for diabetic kidney disease.
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Affiliation(s)
| | - Dilemin Yildiz
- Department of Nephrology, Research Institute of Medical Innovations, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Léa Dionet
- Université Paris Cité, Inserm, PARCC, Paris, France
| | - Daan C. ‘t Hart
- Department of Nephrology, Research Institute of Medical Innovations, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Kim A.T. Verheijden
- Department of Nephrology, Research Institute of Medical Innovations, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Ryuta Saito
- Discovery Technology Laboratories, Sohyaku, Innovative Research Division, Mitsubishi Tanabe Pharma Corporation, Yokohama, Japan
| | | | - Jean-Daniel Delbet
- Université Paris Cité, Inserm, PARCC, Paris, France
- Pediatric Nephrology Department, Armand Trousseau Hospital, DMU Origyne, APHP, Paris and French Reference Center for Rare Diseases MARHEA, Paris, France
| | - Emmanuel Letavernier
- Sorbonne Université, Hôpital Tenon, Paris, France
- INSERM UMR S 1155, Hôpital Tenon, Paris, France
- Explorations Fonctionnelles Multidisciplinaires, AP-HP, Hôpital Tenon, Paris, France
| | - Marion Rabant
- Pathology Department, Necker-Enfants Malades Hospital - Paris, Paris, France
| | - Alexandre Karras
- Université Paris Cité, Inserm, PARCC, Paris, France
- Nephrology Unit, Georges Pompidou European Hospital - Paris, Paris, France
| | - Johan van der Vlag
- Department of Nephrology, Research Institute of Medical Innovations, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Tom Nijenhuis
- Department of Nephrology, Research Institute of Medical Innovations, Radboud University Medical Centre, Nijmegen, The Netherlands
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9
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Wu X, Chen M, Lin S, Chen S, Gu J, Wu Y, Qu M, Gong W, Yao Q, Li H, Zou X, Chen D, Xiao G. Loss of Pinch Proteins Causes Severe Degenerative Disc Disease-Like Lesions in Mice. Aging Dis 2023; 14:1818-1833. [PMID: 37196110 PMCID: PMC10529740 DOI: 10.14336/ad.2023.0212] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Accepted: 02/12/2023] [Indexed: 05/19/2023] Open
Abstract
Degenerative disc disease (DDD) is one of the most common skeletal disorders affecting aged populations. DDD is the leading cause of low back/neck pain, resulting in disability and huge socioeconomic burdens. However, the molecular mechanisms underlying DDD initiation and progression remain poorly understood. Pinch1 and Pinch2 are LIM-domain-containing proteins with crucial functions in mediating multiple fundamental biological processes, such as focal adhesion, cytoskeletal organization, cell proliferation, migration, and survival. In this study, we found that Pinch1 and Pinch2 were both highly expressed in healthy intervertebral discs (IVDs) and dramatically downregulated in degenerative IVDs in mice. Deleting Pinch1 in aggrecan-expressing cells and Pinch2 globally (AggrecanCreERT2; Pinch1fl/fl; Pinch2-/-) caused striking spontaneous DDD-like lesions in lumbar IVDs in mice. Pinch loss inhibited cell proliferation and promoted extracellular matrix (ECM) degradation and apoptosis in lumbar IVDs. Pinch loss markedly enhanced the production of pro-inflammatory cytokines, especially TNFα, in lumbar IVDs and exacerbated instability-induced DDD defects in mice. Pharmacological inhibition of TNFα signaling mitigated the DDD-like lesions caused by Pinch loss. In human degenerative NP samples, reduced expression of Pinch proteins was correlated with severe DDD progression and a markedly upregulated expression of TNFα. Collectively, we demonstrate the crucial role of Pinch proteins in maintaining IVD homeostasis and define a potential therapeutic target for DDD.
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Affiliation(s)
- Xiaohao Wu
- Department of Biochemistry, School of Medicine, Shenzhen Key Laboratory of Cell Microenvironment, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Southern University of Science and Technology, Shenzhen, China.
| | - Mingjue Chen
- Department of Biochemistry, School of Medicine, Shenzhen Key Laboratory of Cell Microenvironment, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Southern University of Science and Technology, Shenzhen, China.
| | - Sixiong Lin
- Guangdong Provincial Key Laboratory of Orthopaedics and Traumatology, Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
| | - Sheng Chen
- Department of Orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei, China.
| | - Jingliang Gu
- Department of Orthopedics, Shanghai municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, China.
| | - Yuchen Wu
- Department of Endocrinology, Chongqing Traditional Chinese Medicine Hospital, Chongqing, China.
| | - Minghao Qu
- Department of Biochemistry, School of Medicine, Shenzhen Key Laboratory of Cell Microenvironment, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Southern University of Science and Technology, Shenzhen, China.
| | - Weiyuan Gong
- Department of Biochemistry, School of Medicine, Shenzhen Key Laboratory of Cell Microenvironment, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Southern University of Science and Technology, Shenzhen, China.
| | - Qing Yao
- Department of Biochemistry, School of Medicine, Shenzhen Key Laboratory of Cell Microenvironment, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Southern University of Science and Technology, Shenzhen, China.
| | - Huiping Li
- Department of Respiratory and Critical Care Medicine, Shenzhen People’s Hospital, Southern University of Science and Technology, Shenzhen, China.
| | - Xuenong Zou
- Guangdong Provincial Key Laboratory of Orthopaedics and Traumatology, Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
| | - Di Chen
- Research Center for Human Tissues and Organs Degeneration, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
| | - Guozhi Xiao
- Department of Biochemistry, School of Medicine, Shenzhen Key Laboratory of Cell Microenvironment, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Southern University of Science and Technology, Shenzhen, China.
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10
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Batool L, Hariharan K, Xu Y, Kaßmann M, Tsvetkov D, Gohlke BO, Kaden S, Gossen M, Nürnberg B, Kurtz A, Gollasch M. An inactivating human TRPC6 channel mutation without focal segmental glomerulosclerosis. Cell Mol Life Sci 2023; 80:265. [PMID: 37615749 PMCID: PMC10449997 DOI: 10.1007/s00018-023-04901-w] [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: 03/24/2023] [Revised: 07/27/2023] [Accepted: 07/28/2023] [Indexed: 08/25/2023]
Abstract
Transient receptor potential cation channel-6 (TRPC6) gene mutations cause familial focal segmental glomerulosclerosis (FSGS), which is inherited as an autosomal dominant disease. In patients with TRPC6-related FSGS, all mutations map to the N- or C-terminal TRPC6 protein domains. Thus far, the majority of TRPC6 mutations are missense resulting in increased or decreased calcium influx; however, the fundamental molecular mechanisms causing cell injury and kidney pathology are unclear. We report a novel heterozygous TRPC6 mutation (V691Kfs*) in a large kindred with no signs of FSGS despite a largely truncated TRPC6 protein. We studied the molecular effects of V691Kfs* TRPC6 mutant using the tridimensional cryo-EM structure of the tetrameric TRPC6 protein. The results indicated that V691 is localized at the pore-forming transmembrane region affecting the ion conduction pathway, and predicted that V691Kfs* causes closure of the ion-conducting pathway leading to channel inactivation. We assessed the impact of V691Kfs* and two previously reported TRPC6 disease mutants (P112Q and G757D) on calcium influx in cells. Our data show that the V691Kfs* fully inactivated the TRCP6 channel-specific calcium influx consistent with a complete loss-of-function phenotype. Furthermore, the V691Kfs* truncation exerted a dominant negative effect on the full-length TRPC6 proteins. In conclusion, the V691Kfs* non-functional truncated TRPC6 is not sufficient to cause FSGS. Our data corroborate recently characterized TRPC6 loss-of-function and gain-of-function mutants suggesting that one defective TRPC6 gene copy is not sufficient to cause FSGS. We underscore the importance of increased rather than reduced calcium influx through TRPC6 for podocyte cell death.
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Affiliation(s)
- Lilas Batool
- BIH Center for Regenerative Therapies (BCRT), Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Krithika Hariharan
- BIH Center for Regenerative Therapies (BCRT), Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
- Fraunhofer-Institute for Biomedical Engineering (IBMT), Fraunhofer Project Center for Stem Cell Process Engineering, Würzburg, Germany
| | - Yao Xu
- Klinik und Poliklinik für Innere Medizin D-Geriatrie, Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, Greifswald, Germany
| | - Mario Kaßmann
- Klinik und Poliklinik für Innere Medizin D-Geriatrie, Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, Greifswald, Germany
| | - Dmitry Tsvetkov
- Klinik und Poliklinik für Innere Medizin D-Geriatrie, Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, Greifswald, Germany
| | - Björn-Oliver Gohlke
- Department of Information Technology, Science-IT, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Sylvia Kaden
- Electron Microscopy Core Facility, German Cancer Research Center, Heidelberg, Germany
| | - Manfred Gossen
- BIH Center for Regenerative Therapies (BCRT), Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
- Institut für Aktive Polymere, Hereon TeltowAbteilung Stammzellmodifikation und Biomaterialien, Teltow, Germany
| | - Bernd Nürnberg
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, University of Tübingen, Tübingen, Germany
| | - Andreas Kurtz
- BIH Center for Regenerative Therapies (BCRT), Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany.
- Biomedical Data and Bioethics, Fraunhofer-Institute for Biomedical Engineering (IBMT), Berlin, Germany.
| | - Maik Gollasch
- Klinik und Poliklinik für Innere Medizin D-Geriatrie, Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, Greifswald, Germany.
- Klinik für Nephrologie und Internistische Intensivmedizin, Charité-Universitätsmedizin Berlin, Berlin, Germany.
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11
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Ueda H, Tran QTH, Tran LNT, Higasa K, Ikeda Y, Kondo N, Hashiyada M, Sato C, Sato Y, Ashida A, Nishio S, Iwata Y, Iida H, Matsuoka D, Hidaka Y, Fukui K, Itami S, Kawashita N, Sugimoto K, Nozu K, Hattori M, Tsukaguchi H. Characterization of cytoskeletal and structural effects of INF2 variants causing glomerulopathy and neuropathy. Sci Rep 2023; 13:12003. [PMID: 37491439 PMCID: PMC10368640 DOI: 10.1038/s41598-023-38588-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 07/11/2023] [Indexed: 07/27/2023] Open
Abstract
Focal segmental glomerulosclerosis (FSGS) is a common glomerular injury leading to end-stage renal disease. Monogenic FSGS is primarily ascribed to decreased podocyte integrity. Variants between residues 184 and 245 of INF2, an actin assembly factor, produce the monogenic FSGS phenotype. Meanwhile, variants between residues 57 and 184 cause a dual-faceted disease involving peripheral neurons and podocytes (Charcot-Marie-Tooth CMT/FSGS). To understand the molecular basis for INF2 disorders, we compared structural and cytoskeletal effects of INF2 variants classified into two subgroups: One (G73D, V108D) causes the CMT/FSGS phenotype, and the other (T161N, N202S) produces monogenic FSGS. Molecular dynamics analysis revealed that all INF2 variants show distinct flexibility compared to the wild-type INF2 and could affect stability of an intramolecular interaction between their N- and C-terminal segments. Immunocytochemistry of cells expressing INF2 variants showed fewer actin stress fibers, and disorganization of cytoplasmic microtubule arrays. Notably, CMT/FSGS variants caused more prominent changes in mitochondrial distribution and fragmentation than FSGS variants and these changes correlated with the severity of cytoskeletal disruption. Our results indicate that CMT/FSGS variants are associated with more severe global cellular defects caused by disrupted cytoskeleton-organelle interactions than are FSGS variants. Further study is needed to clarify tissue-specific pathways and/or cellular functions implicated in FSGS and CMT phenotypes.
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Affiliation(s)
- Hiroko Ueda
- Division of Nephrology, Second Department of Internal Medicine, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, Osaka, 573-1191, Japan
| | - Quynh Thuy Huong Tran
- Division of Nephrology, Second Department of Internal Medicine, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, Osaka, 573-1191, Japan
| | - Linh Nguyen Truc Tran
- Division of Nephrology, Second Department of Internal Medicine, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, Osaka, 573-1191, Japan
| | - Koichiro Higasa
- Department of Genome Analysis, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Yoshiki Ikeda
- Department of Molecular Genetics, Kansai Medical University, Hirakata, Japan
| | - Naoyuki Kondo
- Department of Molecular Genetics, Kansai Medical University, Hirakata, Japan
| | - Masaki Hashiyada
- Department of Legal Medicine, Kansai Medical University, Hirakata, Japan
| | - Chika Sato
- Department of Gynecology and Obstetrics, Kansai Medical University, Hirakata, Japan
| | - Yoshinori Sato
- Division of Nephrology, Department of Medicine, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan
| | - Akira Ashida
- Department of Pediatrics, Osaka Medical and Pharmaceutical University, Takatsuki, Japan
| | - Saori Nishio
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Yasunori Iwata
- Department of Nephrology and Laboratory Medicine, Kanazawa University, Kanazawa, Japan
| | - Hiroyuki Iida
- Department of Internal Medicine, Toyama Prefectural Central Hospital, Toyama, Japan
- Toyama Transplantation Promotion Foundation, Toyama, Japan
| | - Daisuke Matsuoka
- Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Japan
| | - Yoshihiko Hidaka
- Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Japan
| | - Kenji Fukui
- Department of Biochemistry, Faculty of Medicine, Osaka Medical and Pharmaceutical University, Takatsuki, Japan
| | - Suzu Itami
- Major in Science, Graduate School of Science and Engineering, Kindai University, Higashiosaka, Japan
| | - Norihito Kawashita
- Department of Energy and Materials, Faculty of Science and Engineering, Kindai University, Higashiosaka, Japan
| | - Keisuke Sugimoto
- Department of Pediatrics, Kindai University Faculty of Medicine, Osakasayama, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Motoshi Hattori
- Department of Pediatric Nephrology, Tokyo Women's Medical University, Tokyo, Japan
| | - Hiroyasu Tsukaguchi
- Division of Nephrology, Second Department of Internal Medicine, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, Osaka, 573-1191, Japan.
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12
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Rogg M, Maier JI, Helmstädter M, Sammarco A, Kliewe F, Kretz O, Weißer L, Van Wymersch C, Findeisen K, Koessinger AL, Tsoy O, Baumbach J, Grabbert M, Werner M, Huber TB, Endlich N, Schilling O, Schell C. A YAP/TAZ-ARHGAP29-RhoA Signaling Axis Regulates Podocyte Protrusions and Integrin Adhesions. Cells 2023; 12:1795. [PMID: 37443829 PMCID: PMC10340513 DOI: 10.3390/cells12131795] [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: 05/23/2023] [Revised: 06/28/2023] [Accepted: 07/01/2023] [Indexed: 07/15/2023] Open
Abstract
Glomerular disease due to podocyte malfunction is a major factor in the pathogenesis of chronic kidney disease. Identification of podocyte-specific signaling pathways is therefore a prerequisite to characterizing relevant disease pathways and developing novel treatment approaches. Here, we employed loss of function studies for EPB41L5 (Yurt) as a central podocyte gene to generate a cell type-specific disease model. Loss of Yurt in fly nephrocytes caused protein uptake and slit diaphragm defects. Transcriptomic and proteomic analysis of human EPB41L5 knockout podocytes demonstrated impaired mechanotransduction via the YAP/TAZ signaling pathway. Further analysis of specific inhibition of the YAP/TAZ-TEAD transcription factor complex by TEADi led to the identification of ARGHAP29 as an EPB41L5 and YAP/TAZ-dependently expressed podocyte RhoGAP. Knockdown of ARHGAP29 caused increased RhoA activation, defective lamellipodia formation, and increased maturation of integrin adhesion complexes, explaining similar phenotypes caused by loss of EPB41L5 and TEADi expression in podocytes. Detection of increased levels of ARHGAP29 in early disease stages of human glomerular disease implies a novel negative feedback loop for mechanotransductive RhoA-YAP/TAZ signaling in podocyte physiology and disease.
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Affiliation(s)
- Manuel Rogg
- Institute of Surgical Pathology, Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Jasmin I. Maier
- Institute of Surgical Pathology, Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Martin Helmstädter
- Department of Medicine IV, Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Alena Sammarco
- Institute of Surgical Pathology, Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Felix Kliewe
- Department of Anatomy and Cell Biology, University Medicine Greifswald, 17489 Greifswald, Germany (N.E.)
| | - Oliver Kretz
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
- Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Lisa Weißer
- Institute of Surgical Pathology, Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Clara Van Wymersch
- Institute of Surgical Pathology, Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Karla Findeisen
- Institute of Surgical Pathology, Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Anna L. Koessinger
- Institute of Surgical Pathology, Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Olga Tsoy
- Institute for Computational Systems Biology, University of Hamburg, 22607 Hamburg, Germany; (O.T.)
| | - Jan Baumbach
- Institute for Computational Systems Biology, University of Hamburg, 22607 Hamburg, Germany; (O.T.)
- Department of Mathematics and Computer Science, University of Southern Denmark, 5230 Odense, Denmark
| | - Markus Grabbert
- Department of Urology, Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Martin Werner
- Institute of Surgical Pathology, Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Tobias B. Huber
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
- Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Nicole Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, 17489 Greifswald, Germany (N.E.)
| | - Oliver Schilling
- Institute of Surgical Pathology, Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
- Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, 79106 Freiburg, Germany
| | - Christoph Schell
- Institute of Surgical Pathology, Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
- Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, 79106 Freiburg, Germany
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13
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Kaga H, Matsumura H, Saito A, Saito M, Abe F, Suzuki T, Dohmae N, Odaka M, Komatsuda A, Wakui H, Takahashi N. Comparative proteomic analysis of glomerular proteins in IgA nephropathy and IgA vasculitis with nephritis. Clin Proteomics 2023; 20:21. [PMID: 37179321 PMCID: PMC10182656 DOI: 10.1186/s12014-023-09409-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
BACKGROUND IgA nephropathy (IgAN) and IgA vasculitis with nephritis (IgAVN) are related glomerular diseases characterized by marked similarities in immunological and histological findings. We herein performed a comparative proteomic analysis of glomerular proteins in IgAN and IgAVN. METHODS We used renal biopsy specimens from 6 IgAN patients without nephrotic syndrome (NS) (IgAN-I subgroup), 6 IgAN patients with NS (IgAN-II subgroup), 6 IgAVN patients with 0-8.0% of glomeruli with crescent formation (IgAVN-I subgroup), 6 IgAVN patients with 21.2-44.8% of glomeruli with crescent formation (IgAVN-II subgroup), 9 IgAVN patients without NS (IgAVN-III subgroup), 3 IgAVN patients with NS (IgAN-IV subgroup), and 5 control cases. Proteins were extracted from laser microdissected glomeruli and analyzed using mass spectrometry. The relative abundance of proteins was compared between groups. An immunohistochemical validation study was also performed. RESULTS More than 850 proteins with high confidence were identified. A principal component analysis revealed a clear separation between IgAN and IgAVN patients and control cases. In further analyses, 546 proteins that were matched with ≥ 2 peptides were selected. The levels of immunoglobulins (IgA, IgG, and IgM), complements (C3, C4A, C5, and C9), complement factor H-related proteins (CFHR) 1 and 5, vitronectin, fibrinogen chains, and transforming growth factor-β inducible gene-h3 were higher (> 2.6 fold) in the IgAN and IgAVN subgroups than in the control group, whereas hornerin levels were lower (< 0.3 fold). Furthermore, C9 and CFHR1 levels were significantly higher in the IgAN group than in the IgAVN group. The abundance of some podocyte-associated proteins and glomerular basement membrane (GBM) proteins was significantly less in the IgAN-II subgroup than in the IgAN-I subgroup as well as in the IgAVN-IV subgroup than in the IgAVN-III subgroup. Among the IgAN and IgAVN subgroups, talin 1 was not detected in the IgAN-II subgroup. This result was supported by immunohistochemical findings. CONCLUSIONS The present results suggest shared molecular mechanisms for glomerular injury in IgAN and IgAVN, except for enhanced glomerular complement activation in IgAN. Differences in the protein abundance of podocyte-associated and GBM proteins between IgAN and IgAVN patients with and without NS may be associated with the severity of proteinuria.
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Affiliation(s)
- Hajime Kaga
- Department of Hematology, Nephrology, and Rheumatology, Akita University Graduate School of Medicine, Akita, Japan
| | - Hirotoshi Matsumura
- Department of Life Science, Graduate School of Engineering Science, Akita University, Akita, Japan.
| | - Ayano Saito
- Department of Hematology, Nephrology, and Rheumatology, Akita University Graduate School of Medicine, Akita, Japan
| | - Masaya Saito
- Department of Hematology, Nephrology, and Rheumatology, Akita University Graduate School of Medicine, Akita, Japan
| | - Fumito Abe
- Department of Hematology, Nephrology, and Rheumatology, Akita University Graduate School of Medicine, Akita, Japan
| | - Takehiro Suzuki
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, Wako, Japan
| | - Naoshi Dohmae
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, Wako, Japan
| | - Masafumi Odaka
- Department of Life Science, Graduate School of Engineering Science, Akita University, Akita, Japan
| | - Atsushi Komatsuda
- Department of Internal Medicine, Ogachi Central Hospital, Yuzawa, Japan
| | - Hideki Wakui
- Emeritus Professor, Akita University, Akita, Japan
| | - Naoto Takahashi
- Department of Hematology, Nephrology, and Rheumatology, Akita University Graduate School of Medicine, Akita, Japan
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14
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Meliambro K, Yang Y, de Cos M, Rodriguez Ballestas E, Malkin C, Haydak J, Lee JR, Salem F, Mariani LH, Gordon RE, Basgen JM, Wen HH, Fu J, Azeloglu EU, He JC, Wong JS, Campbell KN. KIBRA upregulation increases susceptibility to podocyte injury and glomerular disease progression. JCI Insight 2023; 8:e165002. [PMID: 36853804 PMCID: PMC10132156 DOI: 10.1172/jci.insight.165002] [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: 09/01/2022] [Accepted: 02/21/2023] [Indexed: 03/01/2023] Open
Abstract
Despite recent progress in the identification of mediators of podocyte injury, mechanisms underlying podocyte loss remain poorly understood, and cell-specific therapy is lacking. We previously reported that kidney and brain expressed protein (KIBRA), encoded by WWC1, promotes podocyte injury in vitro through activation of the Hippo signaling pathway. KIBRA expression is increased in the glomeruli of patients with focal segmental glomerulosclerosis, and KIBRA depletion in vivo is protective against acute podocyte injury. Here, we tested the consequences of transgenic podocyte-specific WWC1 expression in immortalized human podocytes and in mice, and we explored the association between glomerular WWC1 expression and glomerular disease progression. We found that KIBRA overexpression in immortalized human podocytes promoted cytoplasmic localization of Yes-associated protein (YAP), induced actin cytoskeletal reorganization, and altered focal adhesion expression and morphology. WWC1-transgenic (KIBRA-overexpressing) mice were more susceptible to acute and chronic glomerular injury, with evidence of YAP inhibition in vivo. Of clinical relevance, glomerular WWC1 expression negatively correlated with renal survival among patients with primary glomerular diseases. These findings highlight the importance of KIBRA/YAP signaling to the regulation of podocyte structural integrity and identify KIBRA-mediated injury as a potential target for podocyte-specific therapy in glomerular disease.
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Affiliation(s)
- Kristin Meliambro
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Yanfeng Yang
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Marina de Cos
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | | | - Caroline Malkin
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Jonathan Haydak
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - John R. Lee
- Division of Nephrology and Hypertension, Department of Medicine, Weill Cornell Medicine, New York, New York, USA
| | - Fadi Salem
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Jacksonville, Florida, USA
| | - Laura H. Mariani
- Division of Nephrology, Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Ronald E. Gordon
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - John M. Basgen
- Stereology and Morphometry Laboratory, Charles R. Drew University of Medicine and Science, Los Angeles, California, USA
| | - Huei Hsun Wen
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Jia Fu
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Evren U. Azeloglu
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - John Cijiang He
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Jenny S. Wong
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Kirk N. Campbell
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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15
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Li D, Liu L, Murea M, Freedman BI, Ma L. Bioinformatics Analysis Reveals a Shared Pathway for Common Forms of Adult Nephrotic Syndrome. KIDNEY360 2023; 4:e515-e524. [PMID: 36763793 PMCID: PMC10278839 DOI: 10.34067/kid.0000000000000074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 01/20/2023] [Indexed: 02/12/2023]
Abstract
Key Points Dysregulation of the focal adhesion pathway is present in the three most common forms of glomerular disease, that is, Focal segmental glomerulosclerosis, membranous nephropathy, and minimal change disease. Zyxin is seen to be upregulated in the glomerular compartment of patients with the three most common forms of glomerular disease. Background Focal segmental glomerulosclerosis, membranous nephropathy, and minimal change disease are common causes of nephrotic syndrome. Although triggers for these diseases differ, disease progression may share common molecular mechanisms. The aim of this study was to investigate the presence of molecular pathways that are dysregulated across these glomerular diseases. Methods The gene expression dataset GSE200828 from the Nephrotic Syndrome Study Network study was obtained from the Gene Expression Omnibus database. R and Python packages, Cytoscape software, and online tools (DAVID and STRING) were used to identify core genes and topologically relevant nodes and molecular pathways. Single-cell RNA sequencing analysis was applied to identify the expression patterns of core genes across kidney cell types in glomerular compartments. Results A total of 1087 differentially expressed genes were identified, including 691 upregulated genes and 396 downregulated genes, which are common in all three forms of nephrotic syndrome compared with kidney donor controls (FDR P <0.01). A multiapproach bioinformatics analysis narrowed down to 28 similarly dysregulated genes across the three proteinuric glomerulopathies. The most topologically relevant nodes belonged to the adherens junction, focal adhesion, and cytoskeleton pathways, where zyxin covers all of those gene ontology terms. Conclusions We report that dysregulation of cell adhesion complexes was present in the three most common forms of glomerular disease. Zyxin could be a biomarker in all three common forms of nephrotic syndrome. If further functional studies confirm its role in their development, zyxin could be a potential therapeutic target.
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Affiliation(s)
- DengFeng Li
- Informatics and Analytics, The University of North Carolina at Greensboro, Greensboro, North Carolina
| | - Liang Liu
- Bioinformatics Shared Resource, Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - Mariana Murea
- Department of Internal Medicine—Nephrology, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - Barry I. Freedman
- Department of Internal Medicine—Nephrology, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - Lijun Ma
- Department of Internal Medicine—Nephrology, Wake Forest University School of Medicine, Winston-Salem, North Carolina
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16
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Medina Rangel PX, Tian X. Understanding Nephrotic Syndrome Using Kidney Transcriptome Profiling and Computational Studies. KIDNEY360 2023; 4:e431-e433. [PMID: 37103957 PMCID: PMC10371383 DOI: 10.34067/kid.0000000000000117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
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17
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Manera M, Casciano F, Giari L. Ultrastructural Alterations of the Glomerular Filtration Barrier in Fish Experimentally Exposed to Perfluorooctanoic Acid. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:5253. [PMID: 37047869 PMCID: PMC10094651 DOI: 10.3390/ijerph20075253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/17/2023] [Accepted: 03/22/2023] [Indexed: 06/19/2023]
Abstract
Per- and polyfluoroalkyl substances can be referred to as the most critical group of contaminants of emerging concern. They can accumulate in high concentration in the kidney and are known to potentially affect its function. Nonetheless, there is a lack of knowledge about their morphopathological effect on the glomerular filtration barrier. Since previous research suggests perfluorooctanoic acid (PFOA) induces glomerular protein leakage, the glomerular filtration barrier of 30 carp from the same parental stock (10 unexposed; 10 exposed to 200 ng L-1 of PFOA; and 10 exposed to 2 mg L-1 of PFOA for 56 days) was screened for possible PFOA-induced ultrastructural lesions in order to shed light on the related pathophysiology. PFOA exposure affected the glomerular filtration barrier in carp experimentally exposed to 2 mg L-1, showing ultrastructural alterations compatible with glomerulonephrosis: podocyte effacement, reduction of filtration slits and filtration slit diaphragms, basement membrane disarrangement, and occurrence of proteinaceous material in the urinary space. The results of the present research confirm the glomerular origin of the PFOA-induced protein leakage and can contribute to the mechanistic comprehension of PFOA's impact on renal function and to the assessment of the exposure effect of environmental pollutants on animals and humans, according to the One Health approach.
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Affiliation(s)
- Maurizio Manera
- Department of Biosciences, Food and Environmental Technologies, University of Teramo, St. R. Balzarini 1, 64100 Teramo, Italy
| | - Fabio Casciano
- Department of Translational Medicine and LTTA Centre, University of Ferrara, St. Fossato di Mortara 70, 44121 Ferrara, Italy
| | - Luisa Giari
- Department of Environmental and Prevention Sciences, University of Ferrara, St. Borsari 46, 44121 Ferrara, Italy
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18
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Medina Rangel PX, Cross E, Liu C, Pedigo CE, Tian X, Gutiérrez-Calabrés E, Nagata S, Priyadarshini A, Lerner G, Bunda P, Perincheri S, Gu J, Zhao H, Wang Y, Inoue K, Ishibe S. Cell Cycle and Senescence Regulation by Podocyte Histone Deacetylase 1 and 2. J Am Soc Nephrol 2023; 34:433-450. [PMID: 36414418 PMCID: PMC10103311 DOI: 10.1681/asn.2022050598] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 10/17/2022] [Accepted: 11/06/2022] [Indexed: 11/24/2022] Open
Abstract
SIGNIFICANCE STATEMENT The loss of integrity of the glomerular filtration barrier results in proteinuria that is often attributed to podocyte loss. Yet how damaged podocytes are lost remains unknown. Germline loss of murine podocyte-associated Hdac1 and Hdac2 ( Hdac1/2 ) results in proteinuria and collapsing glomerulopathy due to sustained double-stranded DNA damage. Hdac1/2 deletion induces loss of podocyte quiescence, cell cycle entry, arrest in G1, and podocyte senescence, observed both in vivo and in vitro . Through the senescence secretory associated phenotype, podocytes secrete proteins that contribute to their detachment. These results solidify the role of HDACs in cell cycle regulation and senescence, providing important clues in our understanding of how podocytes are lost following injury. BACKGROUND Intact expression of podocyte histone deacetylases (HDAC) during development is essential for maintaining a normal glomerular filtration barrier because of its role in modulating DNA damage and preventing premature senescence. METHODS Germline podocyte-specific Hdac1 and 2 ( Hdac1 / 2 ) double-knockout mice were generated to examine the importance of these enzymes during development. RESULTS Podocyte-specific loss of Hdac1 / 2 in mice resulted in severe proteinuria, kidney failure, and collapsing glomerulopathy. Hdac1 / 2 -deprived podocytes exhibited classic characteristics of senescence, such as senescence-associated β-galactosidase activity and lipofuscin aggregates. In addition, DNA damage, likely caused by epigenetic alterations such as open chromatin conformation, not only resulted in podocyte cell-cycle entry as shown in vivo by Ki67 expression and by FUCCI-2aR mice, but also in p21-mediated cell-cycle arrest. Through the senescence secretory associated phenotype, the damaged podocytes secreted proinflammatory cytokines, growth factors, and matrix metalloproteinases, resulting in subsequent podocyte detachment and loss, evidenced by senescent podocytes in urine. CONCLUSIONS Hdac1 / 2 plays an essential role during development. Loss of these genes in double knockout mice leads to sustained DNA damage and podocyte senescence and loss.
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Affiliation(s)
| | - Elizabeth Cross
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Chang Liu
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Christopher E. Pedigo
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Xuefei Tian
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | | | - Soichiro Nagata
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Anupama Priyadarshini
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Gabriel Lerner
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut
| | - Patricia Bunda
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Sudhir Perincheri
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut
| | - Jianlei Gu
- Department of Biostatistics, Yale University School of Public Health, New Haven, Connecticut
| | - Hongyu Zhao
- Department of Biostatistics, Yale University School of Public Health, New Haven, Connecticut
| | - Ying Wang
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Kazunori Inoue
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Shuta Ishibe
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
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19
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Guo C, Ding Y, Yang A, Geng Y, Liu C, Zhou L, Ma L, Yang Z, Hu F, Jiang K, Cai R, Bai P, Quan M, Deng Y, Wu C, Sun Y. CHILKBP protects against podocyte injury by preserving ZO-1 expression. Cell Mol Life Sci 2022; 80:18. [PMID: 36564652 PMCID: PMC11072396 DOI: 10.1007/s00018-022-04661-z] [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: 09/28/2022] [Revised: 11/30/2022] [Accepted: 12/02/2022] [Indexed: 12/25/2022]
Abstract
Glomerular diseases afflict millions of people and impose an enormous burden on public healthcare costs worldwide. Identification of potential therapeutic targets for preventing glomerular diseases is of considerable clinical importance. CHILKBP is a focal adhesion protein and modulates a wide array of biological functions. However, little is known about the role of CHILKBP in glomerular diseases. To investigate the function of CHILKBP in maintaining the structure and function of podocytes in a physiologic setting, a mouse model (CHILKBP cKO) was generated in which CHILKBP gene was conditionally deleted in podocytes using the Cre-LoxP system. Ablation of CHILKBP in podocytes resulted in massive proteinuria and kidney failure in mice. Histologically, typical podocyte injury including podocyte loss, foot process effacement, and glomerulosclerosis was observed in CHILKBP cKO mice. Mechanistically, we identified ZO-1 as a key junctional protein that interacted with CHILKBP. Loss of CHILKBP in podocytes exhibited a significant reduction of ZO-1 expression, leading to abnormal actin organization, aberrant slit diaphragm protein expression and compromised podocyte filtration capacity. Restoration of CHILKBP or ZO-1 in CHILKBP-deficient podocytes effectively alleviated podocyte injury induced by the loss of CHILKBP in vitro and in vivo. Finally, we showed the glomerular expression of CHILKBP and ZO-1 was decreased in patients with proteinuric kidney diseases. Our findings reveal a novel signaling pathway consisting of CHILKBP and ZO-1 that plays an essential role in maintaining podocyte homeostasis and suggest novel therapeutic approaches to alleviate glomerular diseases.
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Affiliation(s)
- Chen Guo
- Department of Biology, School of Life Sciences, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Southern University of Science and Technology, Shenzhen, 518055, China
- Greater Bay Biomedical InnoCenter, Shenzhen Bay Laboratory, Shenzhen, 518055, China
| | - Yanyan Ding
- Department of Biology, School of Life Sciences, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Aihua Yang
- Department of Biology, School of Life Sciences, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Yiqing Geng
- Department of Biology, School of Life Sciences, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Chengmin Liu
- Department of Biology, School of Life Sciences, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Li Zhou
- Department of Biology, School of Life Sciences, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Luyao Ma
- Department of Biology, School of Life Sciences, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Zhe Yang
- Department of Pathology, The First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Feng Hu
- National Clinical Research Center for Infectious Diseases, Shenzhen Third People's Hospital, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Ke Jiang
- Department of Biology, School of Life Sciences, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Renwei Cai
- Department of Biology, School of Life Sciences, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Panzhu Bai
- Department of Biology, School of Life Sciences, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Meiling Quan
- Department of Biology, School of Life Sciences, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Yi Deng
- Department of Biology, School of Life Sciences, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Chuanyue Wu
- Department of Pathology, School of Medicine, University of Pittsburgh Cancer Institute, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
| | - Ying Sun
- Department of Biology, School of Life Sciences, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Southern University of Science and Technology, Shenzhen, 518055, China.
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20
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Preston R, Meng QJ, Lennon R. The dynamic kidney matrisome - is the circadian clock in control? Matrix Biol 2022; 114:138-155. [PMID: 35569693 DOI: 10.1016/j.matbio.2022.05.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 04/21/2022] [Accepted: 05/10/2022] [Indexed: 02/06/2023]
Abstract
The circadian clock network in mammals is responsible for the temporal coordination of numerous physiological processes that are necessary for homeostasis. Peripheral tissues demonstrate circadian rhythmicity and dysfunction of core clock components has been implicated in the pathogenesis of diseases that are characterized by abnormal extracellular matrix, such as fibrosis (too much disorganized matrix) and tissue breakdown (too little matrix). Kidney disease is characterized by proteinuria, which along with the rate of filtration, displays robust circadian oscillation. Clinical observation and mouse studies suggest the presence of 24 h kidney clocks responsible for circadian oscillation in kidney function. Recent experimental evidence has also revealed that cell-matrix interactions and the biomechanical properties of extracellular matrix have key roles in regulating peripheral circadian clocks and this mechanism appears to be cell- and tissue-type specific. Thus, establishing a temporally resolved kidney matrisome may provide a useful tool for studying the two-way interactions between the extracellular matrix and the intracellular time-keeping mechanisms in this critical niche tissue. This review summarizes the latest genetic and biochemical evidence linking kidney physiology and disease to the circadian system with a particular focus on the extracellular matrix. We also review the experimental approaches and methodologies required to dissect the roles of circadian pathways in specific tissues and outline the translational aspects of circadian biology, including how circadian medicine could be used for the treatment of kidney disease.
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Affiliation(s)
- Rebecca Preston
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester M13 9PT, UK
| | - Qing-Jun Meng
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester M13 9PT, UK.
| | - Rachel Lennon
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester M13 9PT, UK; Department of Pediatric Nephrology, Royal Manchester Children's Hospital, Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9WL, UK.
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21
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Upregulation of OASIS/CREB3L1 in podocytes contributes to the disturbance of kidney homeostasis. Commun Biol 2022; 5:734. [PMID: 35869269 PMCID: PMC9307819 DOI: 10.1038/s42003-022-03709-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 07/12/2022] [Indexed: 12/02/2022] Open
Abstract
Podocyte injury is involved in the onset and progression of various kidney diseases. We previously demonstrated that the transcription factor, old astrocyte specifically induced substance (OASIS) in myofibroblasts, contributes to kidney fibrosis, as a novel role of OASIS in the kidneys. Importantly, we found that OASIS is also expressed in podocytes; however, the pathophysiological significance of OASIS in podocytes remains unknown. Upon lipopolysaccharide (LPS) treatment, there is an increase in OASIS in murine podocytes. Enhanced serum creatinine levels and tubular injury, but not albuminuria and podocyte injury, are attenuated upon podocyte-restricted OASIS knockout in LPS-treated mice, as well as diabetic mice. The protective effects of podocyte-specific OASIS deficiency on tubular injury are mediated by protein kinase C iota (PRKCI/PKCι), which is negatively regulated by OASIS in podocytes. Furthermore, podocyte-restricted OASIS transgenic mice show tubular injury and tubulointerstitial fibrosis, with severe albuminuria and podocyte degeneration. Finally, there is an increase in OASIS-positive podocytes in the glomeruli of patients with minimal change nephrotic syndrome and diabetic nephropathy. Taken together, OASIS in podocytes contributes to podocyte and/or tubular injury, in part through decreased PRKCI. The induction of OASIS in podocytes is a critical event for the disturbance of kidney homeostasis. Upregulation of transcription factor OASIS in podocytes contributes to podocyte and/or tubular injury through decreased PRKCi expression and is a critical event for the disturbance of kidney homeostasis.
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22
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CdGAP maintains podocyte function and modulates focal adhesions in a Src kinase-dependent manner. Sci Rep 2022; 12:18657. [PMID: 36333327 PMCID: PMC9636259 DOI: 10.1038/s41598-022-21634-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 09/29/2022] [Indexed: 11/06/2022] Open
Abstract
Rho GTPases are regulators of the actin cytoskeleton and their activity is modulated by GTPase-activating proteins (GAPs) and guanine nucleotide exchanging factors (GEFs). Glomerular podocytes have numerous actin-based projections called foot processes and their alteration is characteristic of proteinuric kidney diseases. We reported previously that Rac1 hyperactivation in podocytes causes proteinuria and glomerulosclerosis in mice. However, which GAP and GEF modulate Rac1 activity in podocytes remains unknown. Here, using a proximity-based ligation assay, we identified CdGAP (ARHGAP31) and β-PIX (ARHGEF7) as the major regulatory proteins interacting with Rac1 in human podocytes. CdGAP interacted with β-PIX through its basic region, and upon EGF stimulation, they both translocated to the plasma membrane in podocytes. CdGAP-depleted podocytes had altered cell motility and increased basal Rac1 and Cdc42 activities. When stimulated with EGF, CdGAP-depleted podocytes showed impaired β-PIX membrane-translocation and tyrosine phosphorylation, and reduced activities of Src kinase, focal adhesion kinase, and paxillin. Systemic and podocyte-specific CdGAP-knockout mice developed mild but significant proteinuria, which was exacerbated by Adriamycin. Collectively, these findings show that CdGAP contributes to maintain podocyte function and protect them from injury.
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23
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Ye Q, Lan B, Liu H, Persson PB, Lai EY, Mao J. A critical role of the podocyte cytoskeleton in the pathogenesis of glomerular proteinuria and autoimmune podocytopathies. Acta Physiol (Oxf) 2022; 235:e13850. [PMID: 35716094 DOI: 10.1111/apha.13850] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/23/2022] [Accepted: 06/13/2022] [Indexed: 01/19/2023]
Abstract
Selective glomerular filtration relies on the membrane separating the glomerular arterioles from the Bowman space. As a major component of the glomerular filtration barrier, podocytes form foot processes by the actin cytoskeleton, which dynamically adjusts in response to environmental changes to maintain filtration barrier integrity. The slit diaphragms bridge the filtration slits between neighboring foot processes and act as signaling hubs interacting with the actin cytoskeleton. Focal adhesions relay signals to regulate actin dynamics while allowing podocyte adherence to the basement membrane. Mutations in actin regulatory and signaling proteins may disrupt the actin cytoskeleton, resulting in foot process retraction, effacement, and proteinuria. Large-scale gene expression profiling platforms, transgenic animal models, and other in vivo gene delivery methods now enhance our understanding of the interactions among podocyte focal adhesions, slit diaphragms, and actin dynamics. In addition, our team found that at least 66% of idiopathic nephrotic syndrome (INS) children have podocyte autoantibodies, which was defined as a new disease subgroup-, autoimmune podocytopathies. This review outlines the pathophysiological mechanisms of podocyte cytoskeleton protein interactions in proteinuria and glomerular podocytopathy.
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Affiliation(s)
- Qing Ye
- Department of Clinical Laboratory, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, National Children's Regional Medical Center, Hangzhou, China
| | - Bing Lan
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, National Children's Regional Medical Center, Hangzhou, China
| | - Huihui Liu
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, National Children's Regional Medical Center, Hangzhou, China
| | - Pontus B Persson
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Translational Physiology, Berlin, Germany
| | - En Yin Lai
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Translational Physiology, Berlin, Germany.,Department of Physiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, China
| | - Jianhua Mao
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, National Children's Regional Medical Center, Hangzhou, China
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24
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Chen Y, Wang Z, Li Q, Tian M, Zhu Y, Yu L, Wang J, Sun S. CXCL16/ERK1/2 pathway regulates human podocytes growth, migration, apoptosis and epithelial mesenchymal transition. Mol Med Rep 2022; 25:212. [PMID: 35514316 PMCID: PMC9133949 DOI: 10.3892/mmr.2022.12728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Accepted: 04/13/2022] [Indexed: 11/12/2022] Open
Abstract
Primary nephrotic syndrome (PNS) is the commonest glomerular disease affecting children. Previous studies have confirmed that CXC motif chemokine ligand 16 (CXCL16) is involved in the pathogenesis of PNS. However, the exact mechanisms underlying the pathogenesis of PNS remain to be elucidated. Thus, the present study aimed to elucidate the role of CXCL16 in PNS. It was found that the expression of CXCL16 and extracellular signal‑regulated kinases 1 and 2 (ERK1/2) were significantly increased in clinical PNS renal tissues using reverse transcription‑quantitative PCR, western blot analysis and immunohistochemistry. Lentivirus overexpression or short hairpin RNA vector was used to induce the overexpression or knockdown of CXCL16 in podocytes, respectively. Overexpression of CXCL16 in podocytes could decrease the cell proliferation and increase the migration and apoptosis, whereas CXCL16 knockdown increased cell proliferation and decreased cell migration and apoptosis. Results of the present study further demonstrated that ERK2 protein expression was regulated by CXCL16. The knockdown of ERK2 expression reversed the effects of CXCL16 on the proliferation, apoptosis, migration and epithelial mesenchymal transition (EMT) of podocytes. Collectively, the findings of the present study highlighted that the CXCL16/ERK1/2 pathway regulates the growth, migration, apoptosis and EMT of human podocytes.
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Affiliation(s)
- Yuan Chen
- Department of Pediatrics, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong 250021, P.R. China
- Department of Pediatrics, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, P.R. China
| | - Zhiyi Wang
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong 250021, P.R. China
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, P.R. China
| | - Qian Li
- Department of Pediatrics, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong 250021, P.R. China
- Department of Pediatrics, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, P.R. China
| | - Minle Tian
- Department of Pediatrics, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong 250021, P.R. China
| | - Yanji Zhu
- Department of Pediatrics, People's Hospital of Rizhao, Rizhao, Shandong 276800, P.R. China
| | - Lichun Yu
- Department of Pediatrics, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong 250021, P.R. China
- Department of Pediatrics, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, P.R. China
| | - Jing Wang
- Department of Pediatrics, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong 250021, P.R. China
- Department of Pediatrics, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, P.R. China
| | - Shuzhen Sun
- Department of Pediatrics, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong 250021, P.R. China
- Department of Pediatrics, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, P.R. China
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25
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Sasaki H, Sasaki N. Tensin 2-deficient nephropathy - mechanosensitive nephropathy, genetic susceptibility. Exp Anim 2022; 71:252-263. [PMID: 35444113 PMCID: PMC9388341 DOI: 10.1538/expanim.22-0031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Tensin 2 (TNS2), a focal adhesion protein, is considered to anchor focal adhesion proteins to β integrin as an integrin adaptor protein and/or serve as a scaffold to facilitate the
interactions of these proteins. In the kidney, TNS2 localizes to the basolateral surface of glomerular epithelial cells, i.e., podocytes. Loss of TNS2 leads to the development of glomerular
basement membrane lesions and abnormal accumulation of extracellular matrix in maturing glomeruli during the early postnatal stages. It subsequently results in podocyte foot process
effacement, eventually leading to glomerulosclerosis. Histopathological features of the affected glomeruli in the middle stage of the disease include expansion of the mesangial matrix
without mesangial cell proliferation. In this review, we provide an overview of TNS2-deficient nephropathy and discuss the potential mechanism underlying this mechanosensitive nephropathy,
which may be applicable to other glomerulonephropathies, such as CD151-deficient nephropathy and Alport syndrome. The onset of TNS2-deficient nephropathy strictly depends on the genetic
background, indicating the presence of critical modifier genes. A better understanding of molecular mechanisms of mechanosensitive nephropathy may open new avenues for the management of
patients with glomerulonephropathies.
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Affiliation(s)
- Hayato Sasaki
- Laboratory of Laboratory Animal Science and Medicine, School of Veterinary Medicine, Kitasato University
| | - Nobuya Sasaki
- Laboratory of Laboratory Animal Science and Medicine, School of Veterinary Medicine, Kitasato University
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26
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Vaughan RH, Kresse J, Farmer LK, Thézénas ML, Kessler BM, Lindeman JHN, Sharples EJ, Welsh GI, Nørregaard R, Ploeg RJ, Kaisar M. Cytoskeletal protein degradation in brain death donor kidneys associates with adverse posttransplant outcomes. Am J Transplant 2022; 22:1073-1087. [PMID: 34878723 PMCID: PMC9305475 DOI: 10.1111/ajt.16912] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 11/16/2021] [Accepted: 11/17/2021] [Indexed: 01/25/2023]
Abstract
In brain death, cerebral injury contributes to systemic biological dysregulation, causing significant cellular stress in donor kidneys adversely impacting the quality of grafts. Here, we hypothesized that donation after brain death (DBD) kidneys undergo proteolytic processes that may deem grafts susceptible to posttransplant dysfunction. Using mass spectrometry and immunoblotting, we mapped degradation profiles of cytoskeletal proteins in deceased and living donor kidney biopsies. We found that key cytoskeletal proteins in DBD kidneys were proteolytically cleaved, generating peptide fragments, predominantly in grafts with suboptimal posttransplant function. Interestingly, α-actinin-4 and talin-1 proteolytic fragments were detected in brain death but not in circulatory death or living donor kidneys with similar donor characteristics. As talin-1 is a specific proteolytic target of calpain-1, we investigated a potential trigger of calpain activation and talin-1 degradation using human ex vivo precision-cut kidney slices and in vitro podocytes. Notably, we showed that activation of calpain-1 by transforming growth factor-β generated proteolytic fragments of talin-1 that matched the degradation fragments detected in DBD preimplantation kidneys, also causing dysregulation of the actin cytoskeleton in human podocytes; events that were reversed by calpain-1 inhibition. Our data provide initial evidence that brain death donor kidneys are more susceptible to cytoskeletal protein degradation. Correlation to posttransplant outcomes may be established by future studies.
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Affiliation(s)
- Rebecca H. Vaughan
- Research and DevelopmentNHS Blood and TransplantBristol & OxfordUK,Nuffield Department of Surgical SciencesOxford University Hospital OxfordBiomedical Research CentreUniversity of OxfordOxfordUK
| | | | - Louise K. Farmer
- Bristol RenalBristol Medical SchoolUniversity of BristolBristolUK
| | - Marie L. Thézénas
- Nuffield Department of MedicineTarget Discovery InstituteUniversity of OxfordOxfordUK
| | - Benedikt M. Kessler
- Nuffield Department of MedicineTarget Discovery InstituteUniversity of OxfordOxfordUK
| | - Jan H. N. Lindeman
- Department of SurgeryLeiden University Medical CentreLeidenThe Netherlands
| | | | - Gavin I. Welsh
- Bristol RenalBristol Medical SchoolUniversity of BristolBristolUK
| | | | - Rutger J. Ploeg
- Research and DevelopmentNHS Blood and TransplantBristol & OxfordUK,Nuffield Department of Surgical SciencesOxford University Hospital OxfordBiomedical Research CentreUniversity of OxfordOxfordUK,Department of SurgeryLeiden University Medical CentreLeidenThe Netherlands
| | - Maria Kaisar
- Research and DevelopmentNHS Blood and TransplantBristol & OxfordUK,Nuffield Department of Surgical SciencesOxford University Hospital OxfordBiomedical Research CentreUniversity of OxfordOxfordUK
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27
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Fang Y, Chen B, Liu Z, Gong AY, Gunning WT, Ge Y, Malhotra D, Gohara AF, Dworkin LD, Gong R. Age-related GSK3β overexpression drives podocyte senescence and glomerular aging. J Clin Invest 2022; 132:141848. [PMID: 35166234 PMCID: PMC8843754 DOI: 10.1172/jci141848] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 12/21/2021] [Indexed: 12/12/2022] Open
Abstract
As life expectancy continues to increase, clinicians are challenged by age-related renal impairment that involves podocyte senescence and glomerulosclerosis. There is now compelling evidence that lithium has a potent antiaging activity that ameliorates brain aging and increases longevity in Drosophila and Caenorhabditis elegans. As the major molecular target of lithium action and a multitasking protein kinase recently implicated in a variety of renal diseases, glycogen synthase kinase 3β (GSK3β) is overexpressed and hyperactive with age in glomerular podocytes, correlating with functional and histological signs of kidney aging. Moreover, podocyte-specific ablation of GSK3β substantially attenuated podocyte senescence and glomerular aging in mice. Mechanistically, key mediators of senescence signaling, such as p16INK4A and p53, contain high numbers of GSK3β consensus motifs, physically interact with GSK3β, and act as its putative substrates. In addition, therapeutic targeting of GSK3β by microdose lithium later in life reduced senescence signaling and delayed kidney aging in mice. Furthermore, in psychiatric patients, lithium carbonate therapy inhibited GSK3β activity and mitigated senescence signaling in urinary exfoliated podocytes and was associated with preservation of kidney function. Thus, GSK3β appears to play a key role in podocyte senescence by modulating senescence signaling and may be an actionable senostatic target to delay kidney aging.
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Affiliation(s)
- Yudong Fang
- Division of Nephrology, Department of Medicine and.,Center for Hypertension and Precision Medicine, University of Toledo College of Medicine, Toledo, Ohio, USA.,Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Bohan Chen
- Division of Nephrology, Department of Medicine and.,Division of Kidney Disease and Hypertension, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - Zhangsuo Liu
- Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | | | | | - Yan Ge
- Division of Nephrology, Department of Medicine and
| | | | | | - Lance D Dworkin
- Division of Nephrology, Department of Medicine and.,Center for Hypertension and Precision Medicine, University of Toledo College of Medicine, Toledo, Ohio, USA.,Division of Kidney Disease and Hypertension, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - Rujun Gong
- Division of Nephrology, Department of Medicine and.,Center for Hypertension and Precision Medicine, University of Toledo College of Medicine, Toledo, Ohio, USA.,Division of Kidney Disease and Hypertension, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA.,Department of Physiology and Pharmacology, University of Toledo College of Medicine, Toledo, Ohio, USA
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28
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Qu C, Roth R, Puapatanakul P, Loitman C, Hammad D, Genin GM, Miner JH, Suleiman HY. Three-Dimensional Visualization of the Podocyte Actin Network Using Integrated Membrane Extraction, Electron Microscopy, and Machine Learning. J Am Soc Nephrol 2022; 33:155-173. [PMID: 34758982 PMCID: PMC8763187 DOI: 10.1681/asn.2021020182] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 10/19/2021] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Actin stress fibers are abundant in cultured cells, but little is known about them in vivo. In podocytes, much evidence suggests that mechanobiologic mechanisms underlie podocyte shape and adhesion in health and in injury, with structural changes to actin stress fibers potentially responsible for pathologic changes to cell morphology. However, this hypothesis is difficult to rigorously test in vivo due to challenges with visualization. A technology to image the actin cytoskeleton at high resolution is needed to better understand the role of structures such as actin stress fibers in podocytes. METHODS We developed the first visualization technique capable of resolving the three-dimensional cytoskeletal network in mouse podocytes in detail, while definitively identifying the proteins that comprise this network. This technique integrates membrane extraction, focused ion-beam scanning electron microscopy, and machine learning image segmentation. RESULTS Using isolated mouse glomeruli from healthy animals, we observed actin cables and intermediate filaments linking the interdigitated podocyte foot processes to newly described contractile actin structures, located at the periphery of the podocyte cell body. Actin cables within foot processes formed a continuous, mesh-like, electron-dense sheet that incorporated the slit diaphragms. CONCLUSIONS Our new technique revealed, for the first time, the detailed three-dimensional organization of actin networks in healthy podocytes. In addition to being consistent with the gel compression hypothesis, which posits that foot processes connected by slit diaphragms act together to counterbalance the hydrodynamic forces across the glomerular filtration barrier, our data provide insight into how podocytes respond to mechanical cues from their surrounding environment.
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Affiliation(s)
- Chengqing Qu
- Department of Mechanical Engineering, National Science Foundation Science and Technology Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, Missouri
| | - Robyn Roth
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri
| | | | - Charles Loitman
- Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri
| | - Dina Hammad
- Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri
| | - Guy M. Genin
- Department of Mechanical Engineering, National Science Foundation Science and Technology Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, Missouri
| | - Jeffrey H. Miner
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri,Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri
| | - Hani Y. Suleiman
- Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri
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29
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Ding Y, Tang X, Wang Y, Yu D, Zhu C, Yu J. Tetrandrine alleviates podocyte injury via calcium-dependent calpain-1 signaling blockade. BMC Complement Med Ther 2021; 21:296. [PMID: 34906112 PMCID: PMC8670271 DOI: 10.1186/s12906-021-03469-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 11/26/2021] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Podocytes have become a crucial target for interventions in proteinuric kidney diseases. Many studies have reported that overexpression of transient receptor potential cation channel protein 6 (TRPC6) in podocyte injury upregulates intracellular Ca2+ influx and stimulates Ca2+-dependent protease calpain-1 signaling. The traditional Chinese drug, tetrandrine, a nonselective Ca2+ channel blocker, has long been used to treat chronic kidney disease. This research aimed to explore the possible mechanisms underlying the anti-proteinuric properties of tetrandrine. METHODS We investigated the involvement of tetrandrine in Ca2+ dependent calpain-1 signaling in mouse podocytes and adriamycin-induced nephropathy rats. Cyclosporine A (CsA) and U73122 were used as positive controls. Cell viability, cytotoxicity, Ca2+ concentration, calpain activity, and mRNA and protein expression levels of calpain-1 signaling pathways were examined. The clinical and pathological changes were measured. RESULTS Tetrandrine decreased intracellular Ca2+ influx in cultured TRPC6-overexpressing podocytes. In both in vitro and in vivo studies, the administration of tetrandrine downregulated calpain activity and the expression of calpain-1 and restored the expression of downstream Talin-1 and nephrin. Compared to CsA, tetrandrine treatment exhibited superior inhibitory effects on calpain activity and calpain-1 expression. CONCLUSIONS Tetrandrine has therapeutic potential in podocyte damage by blocking Ca2+-dependent activation of the calpain-1 signaling pathway. Tetrandrine reduced proteinuria, improved renal function, and alleviate renal pathological damage.
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Affiliation(s)
- Yin Ding
- Department of Nephrology (Key laboratory of Management of Kidney Disease in Zhejiang Province), Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University, Tiyuchang Road 453, Hangzhou, 310007, People's Republic of China
| | - Xuanli Tang
- Department of Nephrology (Key laboratory of Management of Kidney Disease in Zhejiang Province), Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University, Tiyuchang Road 453, Hangzhou, 310007, People's Republic of China
| | - Yuhui Wang
- Department of Nephrology (Key laboratory of Management of Kidney Disease in Zhejiang Province), Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University, Tiyuchang Road 453, Hangzhou, 310007, People's Republic of China
| | - Dongrong Yu
- Department of Nephrology (Key laboratory of Management of Kidney Disease in Zhejiang Province), Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University, Tiyuchang Road 453, Hangzhou, 310007, People's Republic of China
| | - Caifeng Zhu
- Department of Nephrology (Key laboratory of Management of Kidney Disease in Zhejiang Province), Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University, Tiyuchang Road 453, Hangzhou, 310007, People's Republic of China
| | - Jin Yu
- Department of Nephrology (Key laboratory of Management of Kidney Disease in Zhejiang Province), Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University, Tiyuchang Road 453, Hangzhou, 310007, People's Republic of China.
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30
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Yin L, Yu L, He JC, Chen A. Controversies in Podocyte Loss: Death or Detachment? Front Cell Dev Biol 2021; 9:771931. [PMID: 34881244 PMCID: PMC8645964 DOI: 10.3389/fcell.2021.771931] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 11/03/2021] [Indexed: 12/21/2022] Open
Abstract
Glomerular podocytes are characterized by terminally differentiated epithelial cells with limited proliferating ability; thus, podocyte loss could not be fully compensated by podocyte regeneration. A large body of clinical studies collectively demonstrated that podocyte loss correlated with glomerular diseases progression. Both podocyte death and podocyte detachment lead to podocyte loss; however, which one is the main cause remains controversial. Up to date, multiple mechanisms are involved in podocyte death, including programmed apoptotic cell death (apoptosis and anoikis), programmed nonapoptotic cell death (autophagy, entosis, and podoptosis), immune-related cell death (pyroptosis), and other types of cell death (necroptosis and mitotic catastrophe-related cell death). Apoptosis is considered a common mechanism of podocyte loss; however, most of the data were generated in vitro and the evidence of in vivo podocyte apoptosis is limited. The isolation of podocytes in the urine and subsequent culture of urinary podocytes in vitro suggest that detachment of viable podocytes could be another important mechanism for podocyte loss. In this review, we summarize recent advances that address this controversial topic on the specific circumstances of podocyte loss.
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Affiliation(s)
- Lijun Yin
- Hunan Key Laboratory of Kidney Disease and Blood Purification, Department of Nephrology, Institute of Nephrology, The Second Xiangya Hospital at Central South University, Changsha, China
| | - Lu Yu
- Hunan Key Laboratory of Kidney Disease and Blood Purification, Department of Nephrology, Institute of Nephrology, The Second Xiangya Hospital at Central South University, Changsha, China.,Department of Health Sciences, Boston University College of Health and Rehabilitation Sciences: Sargent College, Boston University, Boston, MA, United States
| | - John Cijiang He
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States.,Renal Program, James J. Peters Veterans Affairs Medical Center at Bronx, New York, NY, United States
| | - Anqun Chen
- Hunan Key Laboratory of Kidney Disease and Blood Purification, Department of Nephrology, Institute of Nephrology, The Second Xiangya Hospital at Central South University, Changsha, China
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31
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Gao H, Zhong Y, Ding Z, Lin S, Hou X, Tang W, Zhou X, Zou X, Shao J, Yang F, Bai X, Liu C, Cao H, Xiao G. Pinch Loss Ameliorates Obesity, Glucose Intolerance, and Fatty Liver by Modulating Adipocyte Apoptosis in Mice. Diabetes 2021; 70:2492-2505. [PMID: 34380695 DOI: 10.2337/db21-0392] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 08/05/2021] [Indexed: 11/13/2022]
Abstract
The mammalian focal adhesion proteins Pinch1/2 activate integrins and promote cell-extracellular matrix adhesion and migration; however, their roles in adipose tissue and metabolism are unclear. Here we find that high-fat diet (HFD) feeding dramatically increases expression of Pinch1/2 proteins in white adipose tissue (WAT) in mice. Furthermore, expression of Pinch1 is largely upregulated in WAT in leptin-deficient ob/ob type 2 diabetic mice and obese humans. While mice with loss of Pinch1 in adipocytes or global Pinch2 do not display any notable phenotypes, deleting Pinch1 in adipocytes and Pinch2 globally significantly decreases body weight and WAT mass, but not brown adipose tissue mass, in HFD-fed, but not normal chow diet-fed, mice. Pinch loss ameliorates HFD-induced glucose intolerance and fatty liver. After HFD challenge, Pinch loss slightly but significantly accelerates energy expenditure. While Pinch loss decreases adipocyte size and alters adipocyte size distribution, it greatly accelerates cell apoptosis primarily in epididymal WAT and to a lesser extent in subcutaneous WAT. In vitro studies demonstrate that Pinch loss accelerates adipocyte apoptosis by activating the Bim/Caspase-8 pathway. In vivo, genetic ablation of Caspase-8 expression in adipocytes essentially abolishes the ameliorating effects of Pinch deficiency on obesity, glucose intolerance, and fatty liver in mice. Thus, we demonstrate a previously unknown function of Pinch in control of adipose mass, glucose, and fat metabolism via modulation of adipocyte apoptosis. We may define a novel target for the prevention and treatment of metabolic diseases, such as obesity and diabetes.
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Affiliation(s)
- Huanqing Gao
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Yiming Zhong
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Zhen Ding
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Sixiong Lin
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen, China
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Department of Spinal Surgery, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Xiaoting Hou
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Wanze Tang
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Xiaoqian Zhou
- Department of Gastroenterology, First People's Hospital of Guiyang, Guiyang, China
| | - Xuenong Zou
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Department of Spinal Surgery, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Jie Shao
- Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Fan Yang
- Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Xiaochun Bai
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Chuanju Liu
- Departments of Orthopedic Surgery and Cell Biology, New York University School of Medicine, New York, NY
| | - Huiling Cao
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Guozhi Xiao
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen, China
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32
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van Leeuwen LL, Spraakman NA, Brat A, Huang H, Thorne AM, Bonham S, van Balkom BWM, Ploeg RJ, Kessler BM, Leuvenink HGD. Proteomic analysis of machine perfusion solution from brain dead donor kidneys reveals that elevated complement, cytoskeleton and lipid metabolism proteins are associated with 1-year outcome. Transpl Int 2021; 34:1618-1629. [PMID: 34448265 PMCID: PMC9292651 DOI: 10.1111/tri.13984] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/14/2021] [Accepted: 07/15/2021] [Indexed: 11/29/2022]
Abstract
Assessment of donor kidney quality is based on clinical scores or requires biopsies for histological assessment. Noninvasive strategies to identify and predict graft outcome at an early stage are, therefore, needed. We evaluated the perfusate of donation after brain death (DBD) kidneys during nonoxygenated hypothermic machine perfusion (HMP). In particular, we compared perfusate protein profiles of good outcome (GO) and suboptimal outcome (SO) 1‐year post‐transplantation. Samples taken 15 min after the start HMP (T1) and before the termination of HMP (T2) were analysed using quantitative liquid chromatography–tandem mass spectrometry (LC‐MS/MS). Hierarchical clustering of the 100 most abundant proteins showed discrimination between grafts with a GO and SO at T1. Elevated levels of proteins involved in classical complement cascades at both T1 and T2 and a reduced abundance of lipid metabolism at T1 and of cytoskeletal proteins at T2 in GO versus SO was observed. ATP‐citrate synthase and fatty acid‐binding protein 5 (T1) and immunoglobulin heavy variable 2‐26 and desmoplakin (T2) showed 91% and 86% predictive values, respectively, for transplant outcome. Taken together, DBD kidney HMP perfusate profiles can distinguish between outcome 1‐year post‐transplantation. Furthermore, it provides insights into mechanisms that could play a role in post‐transplant outcomes.
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Affiliation(s)
- L Leonie van Leeuwen
- Department of Surgery, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands.,Nuffield Department of Medicine, Target Discovery Institute, Centre for Medicines Discovery, University of Oxford, Oxford, UK
| | - Nora A Spraakman
- Department of Anaesthesiology, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
| | - Aukje Brat
- Department of Surgery, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands.,Nuffield Department of Medicine, Target Discovery Institute, Centre for Medicines Discovery, University of Oxford, Oxford, UK
| | - Honglei Huang
- Nuffield Department of Medicine, Target Discovery Institute, Centre for Medicines Discovery, University of Oxford, Oxford, UK.,Nuffield Department of Surgical Sciences, University of Oxford, BRC Oxford and NHS Blood and Transplant, Oxford, UK
| | - Adam M Thorne
- Department of Surgery, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands.,Nuffield Department of Medicine, Target Discovery Institute, Centre for Medicines Discovery, University of Oxford, Oxford, UK
| | - Sarah Bonham
- Nuffield Department of Medicine, Target Discovery Institute, Centre for Medicines Discovery, University of Oxford, Oxford, UK
| | - Bas W M van Balkom
- Department of Nephrology and Hypertension, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Rutger J Ploeg
- Department of Surgery, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands.,Nuffield Department of Surgical Sciences, University of Oxford, BRC Oxford and NHS Blood and Transplant, Oxford, UK
| | - Benedikt M Kessler
- Nuffield Department of Medicine, Target Discovery Institute, Centre for Medicines Discovery, University of Oxford, Oxford, UK
| | - Henri G D Leuvenink
- Department of Surgery, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
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33
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Wang D, Sant S, Ferrell N. A Biomimetic In Vitro Model of the Kidney Filtration Barrier Using Tissue-Derived Glomerular Basement Membrane. Adv Healthc Mater 2021; 10:e2002275. [PMID: 34218528 DOI: 10.1002/adhm.202002275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 05/24/2021] [Indexed: 01/28/2023]
Abstract
The glomerular filtration barrier (GFB) filters the blood to remove toxins while retaining high molecular weight proteins in the circulation. The glomerular basement membrane (GBM) and podocytes, highly specialized epithelial cells, are critical components of the filtration barrier. The GBM serves as a physical barrier to passage of molecules into the filtrate. Podocytes adhere to the filtrate side of the GBM and further restrict passage of high molecular weight molecules into the filtrate. Here, a 3D cell culture model of the glomerular filtration barrier to evaluate the role of the GBM and podocytes in mediating molecular diffusion is developed. GBM is isolated from mammalian kidneys to recapitulate the composition and mechanics of the in vivo basement membrane. The GFB model exhibits molecular selectivity that is comparable to the in vivo filtration barrier. The GBM alone provides a stringent barrier to passage of albumin and Ficoll. Podocytes further restrict molecular diffusion. Damage to the GBM that is typical of diabetic kidney disease is simulated using hypochlorous acid and results in increased molecular diffusion. This system can serve as a platform to evaluate the effects of GBM damage, podocyte injury, and reciprocal effects of altered podocyte-GBM interactions on kidney microvascular permeability.
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Affiliation(s)
- Dan Wang
- Department of Medicine, Division of Nephrology, Vanderbilt University Medical Center, 1161 21st Ave. South, Nashville, TN, 37232, USA
| | - Snehal Sant
- Department of Medicine, Division of Nephrology, Vanderbilt University Medical Center, 1161 21st Ave. South, Nashville, TN, 37232, USA
| | - Nicholas Ferrell
- Department of Medicine, Division of Nephrology, Vanderbilt University Medical Center, 1161 21st Ave. South, Nashville, TN, 37232, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
- Vanderbilt Center for Kidney Disease, S3223 Medical Center North, Nashville, TN, 37232, USA
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34
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Zhou J, Yang J, Wang YM, Ding H, Li TS, Liu ZH, Chen L, Jiao RQ, Zhang DM, Kong LD. IL-6/STAT3 signaling activation exacerbates high fructose-induced podocyte hypertrophy by ketohexokinase-A-mediated tristetraprolin down-regulation. Cell Signal 2021; 86:110082. [PMID: 34252535 DOI: 10.1016/j.cellsig.2021.110082] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/25/2021] [Accepted: 07/06/2021] [Indexed: 02/07/2023]
Abstract
Glomerular hypertrophy is a crucial factor of severe podocyte damage and proteinuria. Our previous study showed that high fructose induced podocyte injury. The current study aimed to explore a novel molecular mechanism underlying podocyte hypertrophy induced by high fructose. Here we demonstrated for the first time that high fructose significantly initiated the hypertrophy in rat glomeruli and differentiated human podocytes (HPCs). Consistently, it induced inflammatory response with the down-regulation of anti-inflammatory factor zinc-finger protein tristetraprolin (TTP) and the activation of interleukin-6 (IL-6)/signal transducer and activator of transcription 3 (STAT3) signaling in these animal and cell models. Subsequently, high-expression of microRNA-92a-3p (miR-92a-3p) and its target protein cyclin-dependent kinase inhibitor p57 (P57) down-regulation, representing abnormal proliferation and apoptosis, were observed in vivo and in vitro. Moreover, high fructose increased ketohexokinase-A (KHK-A) expression in rat glomeruli and differentiated HPCs. Exogenous IL-6 stimulation up-regulated IL-6/STAT3 signaling and miR-92a-3p, reduced P57 expression and promoted podocyte proliferation, apoptosis and hypertrophy in vitro. The data from anti-inflammatory agent maslinic acid treatment or TTP siRNA transfection showed that high fructose may decrease TTP to activate IL-6/STAT3 signaling in podocyte overproliferation and apoptosis, causing podocyte hypertrophy. Whereas, KHK-A siRNA transfection remarkably restored high fructose-induced TTP down-regulation, IL-6/STAT3 signaling activation, podocyte overproliferation, apoptosis and hypertrophy in differentiated HPCs. Taken together, these results suggested that high fructose possibly increased KHK-A expression to down-regulate TTP, subsequently activated IL-6/STAT3 signaling to interfere with podocyte proliferation and apoptosis by up-regulating miR-92a-3p to suppress P57 expression, causing podocyte hypertrophy. Therefore, the inactivation of IL-6/STAT3 to relieve podocyte hypertrophy mediated by inhibiting KHK-A to increase TTP may be a novel strategy for high fructose diet-associated podocyte injury and proteinuria.
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Affiliation(s)
- Jie Zhou
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Jie Yang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Yu-Meng Wang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Hong Ding
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Tu-Shuai Li
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Zhi-Hong Liu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Li Chen
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Rui-Qing Jiao
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Dong-Mei Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Ling-Dong Kong
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China.
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Cytoskeleton Rearrangements Modulate TRPC6 Channel Activity in Podocytes. Int J Mol Sci 2021; 22:ijms22094396. [PMID: 33922367 PMCID: PMC8122765 DOI: 10.3390/ijms22094396] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 04/16/2021] [Accepted: 04/20/2021] [Indexed: 12/15/2022] Open
Abstract
The actin cytoskeleton of podocytes plays a central role in the functioning of the filtration barrier in the kidney. Calcium entry into podocytes via TRPC6 (Transient Receptor Potential Canonical 6) channels leads to actin cytoskeleton rearrangement, thereby affecting the filtration barrier. We hypothesized that there is feedback from the cytoskeleton that modulates the activity of TRPC6 channels. Experiments using scanning ion-conductance microscopy demonstrated a change in migration properties in podocyte cell cultures treated with cytochalasin D, a pharmacological agent that disrupts the actin cytoskeleton. Cell-attached patch-clamp experiments revealed that cytochalasin D increases the activity of TRPC6 channels in CHO (Chinese Hamster Ovary) cells overexpressing the channel and in podocytes from freshly isolated glomeruli. Furthermore, it was previously reported that mutation in ACTN4, which encodes α-actinin-4, causes focal segmental glomerulosclerosis and solidifies the actin network in podocytes. Therefore, we tested whether α-actinin-4 regulates the activity of TRPC6 channels. We found that co-expression of mutant α-actinin-4 K255E with TRPC6 in CHO cells decreases TRPC6 channel activity. Therefore, our data demonstrate a direct interaction between the structure of the actin cytoskeleton and TRPC6 activity.
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36
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Fukusumi Y, Yasuda H, Zhang Y, Kawachi H. Nephrin-Ephrin-B1-Na +/H + Exchanger Regulatory Factor 2-Ezrin-Actin Axis Is Critical in Podocyte Injury. THE AMERICAN JOURNAL OF PATHOLOGY 2021; 191:1209-1226. [PMID: 33887216 DOI: 10.1016/j.ajpath.2021.04.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/13/2021] [Accepted: 04/05/2021] [Indexed: 10/21/2022]
Abstract
Ephrin-B1 is one of the critical components of the slit diaphragm of kidney glomerular podocyte. However, the precise function of ephrin-B1 is unclear. To clarify the function of ephrin-B1, ephrin-B1-associated molecules were studied. RNA-sequencing analysis suggested that Na+/H+ exchanger regulatory factor 2 (NHERF2), a scaffolding protein, is associated with ephrin-B1. NHERF2 was expressed at the apical area and the slit diaphragm, and interacted with the nephrin-ephrin-B1 complex at the slit diaphragm. The nephrin-ephrin-B1-NHERF2 complex interacted with ezrin bound to F-actin. NHERF2 bound ephrin-B1 via its first postsynaptic density protein-95/disks large/zonula occludens-1 domain, and podocalyxin via its second postsynaptic density protein-95/disks large/zonula occludens-1 domain. Both in vitro analyses with human embryonic kidney 293 cells and in vivo study with rat nephrotic model showed that stimulaiton of the slit diaphragm, phosphorylation of nephrin and ephrin-B1, and dephosphorylation of NHERF2 and ezrin, disrupted the linkages of ephrin-B1-NHERF2 and NHERF2-ezrin. It is conceivable that the linkage of nephrin-ephrin-B1-NHERF2-ezrin-actin is a novel critical axis in the podocytes. Ephrin-B1 phosphorylation also disrupted the linkage of an apical transmembrane protein, podocalyxin, with NHERF2-ezrin-actin. The phosphorylation of ephrin-B1 and the consequent dephosphorylation of NHERF2 are critical initiation events leading to podocyte injury.
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Affiliation(s)
- Yoshiyasu Fukusumi
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hidenori Yasuda
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Ying Zhang
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hiroshi Kawachi
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
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Wang L, Wang P, Li X, Dong Y, Wu S, Xu M, Chen X, Wang S, Zheng C, Zou C. Combination CTLA-4 immunoglobulin treatment and ultrasound microbubble-mediated exposure improve renal function in a rat model of diabetic nephropathy. Aging (Albany NY) 2021; 13:8524-8540. [PMID: 33714204 PMCID: PMC8034886 DOI: 10.18632/aging.202664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 02/01/2021] [Indexed: 12/17/2022]
Abstract
OBJECTIVE This study explored the therapeutic impact of combined cytotoxic T lymphocyte-associated antigen 4 immunoglobulin (CTLA-4-Ig) treatment and microbubble-mediated exposure in a rat model of diabetic nephropathy (DN). METHOD We treated rats using CTLA-4-Ig and/or microbubble exposure. At 8 weeks post-intervention, key parameters were evaluated including blood biochemistry, damage to renal tissue, renal parenchymal elasticity, ultrastructural changes in podocytes, and renal parenchymal expression of CD31, CD34, IL-6, Fn, Collagen I, Talin, Paxillin, α3β1, podocin, nephrin, and B7-1. RESULT We found that renal function in the rat model of DN can be significantly improved by CTLA-4-Ig and CTLA-4-Ig + ultrasound microbubble treatment. Treatment efficacy was associated with reductions in renal parenchymal hardness, decreases in podocyte reduction, decreased IL-6, Fn and Collagen I expression, increased Talin, Paxillin and α3β1 expression, elevated podocin and nephrin expression, and decreased B7-1 expression. In contrast, these treatments did not impact CD31 or CD34 expression within the renal parenchyma. CONCLUSION These findings clearly emphasize that CTLA-4-Ig can effectively prevent podocyte damage, inhibiting inflammation and fibrosis, and thereby treating and preventing DN. In addition, ultrasound microbubble exposure can improve the ability of CTLA-4-Ig to pass through the glomerular basement membrane in order to access podocytes such that combination CTLA-4-Ig + microbubble exposure treatment is superior to treatment with CTLA-4-Ig only.
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Affiliation(s)
- Liang Wang
- Department of Ultrasonic Diagnosis, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Pengfei Wang
- Department of Ultrasonic Diagnosis, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Xiuyun Li
- Department of Ultrasonic Diagnosis, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Yanyan Dong
- Department of Ultrasonic Diagnosis, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Senmin Wu
- Department of Ultrasonic Diagnosis, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Maosheng Xu
- Department of Ultrasonic Diagnosis, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Xiu Chen
- Department of Ultrasonic Diagnosis, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Shijia Wang
- Department of Ultrasonic Diagnosis, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Chao Zheng
- Department of Endocrinology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310000, Zhejiang, China
| | - Chunpeng Zou
- Department of Ultrasonic Diagnosis, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
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38
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EPB41L5 controls podocyte extracellular matrix assembly by adhesome-dependent force transmission. Cell Rep 2021; 34:108883. [PMID: 33761352 DOI: 10.1016/j.celrep.2021.108883] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 12/21/2020] [Accepted: 02/25/2021] [Indexed: 12/14/2022] Open
Abstract
The integrity of the kidney filtration barrier essentially relies on the balanced interplay of podocytes and the glomerular basement membrane (GBM). Here, we show by analysis of in vitro and in vivo models that a loss of the podocyte-specific FERM-domain protein EPB41L5 results in impaired extracellular matrix (ECM) assembly. By using quantitative proteomics analysis of the secretome and matrisome, we demonstrate a shift in ECM composition characterized by diminished deposition of core GBM components, such as LAMA5. Integrin adhesome proteomics reveals that EPB41L5 recruits PDLIM5 and ACTN4 to integrin adhesion complexes (IACs). Consecutively, EPB41L5 knockout podocytes show insufficient maturation of integrin adhesion sites, which translates into impaired force transmission and ECM assembly. These observations build the framework for a model in which EPB41L5 functions as a cell-type-specific regulator of the podocyte adhesome and controls a localized adaptive module in order to prevent podocyte detachment and thereby ensures GBM integrity.
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39
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Müller-Deile J, Sarau G, Kotb AM, Jaremenko C, Rolle-Kampczyk UE, Daniel C, Kalkhof S, Christiansen SH, Schiffer M. Novel diagnostic and therapeutic techniques reveal changed metabolic profiles in recurrent focal segmental glomerulosclerosis. Sci Rep 2021; 11:4577. [PMID: 33633212 PMCID: PMC7907124 DOI: 10.1038/s41598-021-83883-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 02/09/2021] [Indexed: 12/19/2022] Open
Abstract
Idiopathic forms of Focal Segmental Glomerulosclerosis (FSGS) are caused by circulating permeability factors, which can lead to early recurrence of FSGS and kidney failure after kidney transplantation. In the past three decades, many research endeavors were undertaken to identify these unknown factors. Even though some potential candidates have been recently discussed in the literature, "the" actual factor remains elusive. Therefore, there is an increased demand in FSGS research for the use of novel technologies that allow us to study FSGS from a yet unexplored angle. Here, we report the successful treatment of recurrent FSGS in a patient after living-related kidney transplantation by removal of circulating factors with CytoSorb apheresis. Interestingly, the classical published circulating factors were all in normal range in this patient but early disease recurrence in the transplant kidney and immediate response to CytoSorb apheresis were still suggestive for pathogenic circulating factors. To proof the functional effects of the patient's serum on podocytes and the glomerular filtration barrier we used a podocyte cell culture model and a proteinuria model in zebrafish to detect pathogenic effects on the podocytes actin cytoskeleton inducing a functional phenotype and podocyte effacement. We then performed Raman spectroscopy in the < 50 kDa serum fraction, on cultured podocytes treated with the FSGS serum and in kidney biopsies of the same patient at the time of transplantation and at the time of disease recurrence. The analysis revealed changes in podocyte metabolome induced by the FSGS serum as well as in focal glomerular and parietal epithelial cell regions in the FSGS biopsy. Several altered Raman spectra were identified in the fractionated serum and metabolome analysis by mass spectrometry detected lipid profiles in the FSGS serum, which were supported by disturbances in the Raman spectra. Our novel innovative analysis reveals changed lipid metabolome profiles associated with idiopathic FSGS that might reflect a new subtype of the disease.
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Affiliation(s)
- Janina Müller-Deile
- Department of Nephrology and Hypertension, Friedrich-Alexander-University (FAU) Erlangen-Nuremberg, Erlangen, Germany.
| | - George Sarau
- Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Dresden, Germany.,Leuchs Emeritus Group, Max Planck Institute for the Science of Light, Erlangen, Germany.,Institute for Nanotechnology and Correlative Microscopy eV INAM, Forchheim, Germany
| | - Ahmed M Kotb
- Department of Nephrology and Hypertension, Friedrich-Alexander-University (FAU) Erlangen-Nuremberg, Erlangen, Germany.,Department of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, Asyût, Egypt
| | - Christian Jaremenko
- Institute for Nanotechnology and Correlative Microscopy eV INAM, Forchheim, Germany.,Institute of Optics, Information and Photonics, Friedrich-Alexander-University (FAU) Erlangen-Nuremberg, Erlangen, Germany
| | - Ulrike E Rolle-Kampczyk
- Department Molecular Systems Biology, Helmholtz Centre for Environmental Research, Leipzig, Germany
| | - Christoph Daniel
- Department of Nephropathology, Friedrich-Alexander-University (FAU) Erlangen-Nuremberg, Erlangen, Germany
| | - Stefan Kalkhof
- Institute for Bioanalysis, University of Applied Sciences Coburg, Coburg, Germany.,Department of Molecular Systems Biology, Helmholtz-Centre for Environmental Research-UFZ, Leipzig, Germany
| | - Silke H Christiansen
- Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Dresden, Germany.,Leuchs Emeritus Group, Max Planck Institute for the Science of Light, Erlangen, Germany.,Institute for Nanotechnology and Correlative Microscopy eV INAM, Forchheim, Germany.,Physics Department, Freie Universität Berlin, Berlin, Germany
| | - Mario Schiffer
- Department of Nephrology and Hypertension, Friedrich-Alexander-University (FAU) Erlangen-Nuremberg, Erlangen, Germany
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40
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Li Q, Gulati A, Lemaire M, Nottoli T, Bale A, Tufro A. Rho-GTPase Activating Protein myosin MYO9A identified as a novel candidate gene for monogenic focal segmental glomerulosclerosis. Kidney Int 2021; 99:1102-1117. [PMID: 33412162 DOI: 10.1016/j.kint.2020.12.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 12/04/2020] [Accepted: 12/10/2020] [Indexed: 01/18/2023]
Abstract
Focal segmental glomerulosclerosis (FSGS) is a podocytopathy leading to kidney failure, whose molecular cause frequently remains unresolved. Here, we describe a rare MYO9A loss of function nonsense heterozygous mutation (p.Arg701∗) as a possible contributor to disease in a sibling pair with familial FSGS/proteinuria. MYO9A variants of uncertain significance were identified by whole exome sequencing in a cohort of 94 biopsy proven patients with FSGS. MYO9A is an unconventional myosin with a Rho-GAP domain that controls epithelial cell junction assembly, crosslinks and bundles actin and deactivates the small GTPase protein encoded by the RHOA gene. RhoA activity is associated with cytoskeleton regulation of actin stress fiber formation and actomyosin contractility. Myo9A was detected in mouse and human podocytes in vitro and in vivo. Knockin mice carrying the p.Arg701∗MYO9A (Myo9AR701X) generated by gene editing developed proteinuria, podocyte effacement and FSGS. Kidneys and podocytes from Myo9AR701X/+ mutant mice revealed Myo9A haploinsufficiency, increased RhoA activity, decreased Myo9A-actin-calmodulin interaction, impaired podocyte attachment and migration. Our results indicate that Myo9A is a novel component of the podocyte cytoskeletal apparatus that regulates RhoA activity and podocyte function. Thus, Myo9AR701X/+ knock-in mice recapitulate the proband FSGS phenotype, demonstrate that p.R701X Myo9A is an FSGS-causing mutation in mice and suggest that heterozygous loss-of-function MYO9A mutations may cause a novel form of human autosomal dominant FSGS. Hence, identification of MYO9A pathogenic variants in additional individuals with familial or sporadic FSGS is needed to ascertain the gene contribution to disease.
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Affiliation(s)
- Qi Li
- Department of Pediatrics, Nephrology Section, Yale School of Medicine, New Haven, Connecticut, USA
| | - Ashima Gulati
- Department of Internal Medicine, Nephrology Section, Yale School of Medicine, New Haven, Connecticut, USA
| | - Mathieu Lemaire
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut, USA
| | - Timothy Nottoli
- Yale Gene Editing Center, Yale School of Medicine, New Haven, Connecticut, USA
| | - Allen Bale
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut, USA
| | - Alda Tufro
- Department of Pediatrics, Nephrology Section, Yale School of Medicine, New Haven, Connecticut, USA; Department of Cell and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut, USA.
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41
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Bai L, Zhuang J, Zhang C, Lu C, Tian X, Jiang H. Case Report: The Monogenic Familial Steroid-Resistant Nephrotic Syndrome Caused by a Novel Missense Mutation of NPHS2 Gene A593C in a Chinese Family. Front Pediatr 2021; 9:692727. [PMID: 34631609 PMCID: PMC8497038 DOI: 10.3389/fped.2021.692727] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 08/31/2021] [Indexed: 12/04/2022] Open
Abstract
Background: Pathogenic variants in the NPHS2 gene encoding podocin in kidney podocytes are associated with autosomal recessive steroid-resistant nephrotic syndrome (SRNS) by disrupting podocyte function and the integrity of the glomerular filtration barrier. The outcome is generally poor by progressing into end-stage kidney disease (ESKD). With the help of gene diagnostics, we can further understand the role of podocin of podocytes in the development and progression of SRNS. However, the pathological mutation of NPHS2 and clinical relevance remain further elusive. Case Presentation: Two siblings, a 15-year-old girl and her 10-year-old younger brother from a consanguineous Chinese family, presented with nephrotic syndrome. Both of them developed progressive proteinuria starting from the 5-year-old of age. The renal pathological lesions for them revealed focal segmental glomerulosclerosis (FSGS). There was no response to the glucocorticoid, calcineurin inhibitors, and rituximab treatment. The female affected patient received the hemodialysis treatment due to ESKD in June 2020; the male patient was still in follow-up presenting with SRNS. The mutational screening of the two patients and their parents using Trio whole-exome sequencing showed the NPHS2 gene de novo missense mutation in exon 5 (A593C), for which the two siblings were homozygous and their parents confirmed heterozygous asymptomatic carriers. No other SRNS-related gene variants with the SRNS were determined. Conclusion: Pathological gene variants screening in children clinically suspected with SRNS might be helpful in the diagnosis as well as appropriate decisions on treatment strategies and prediction of prognosis.
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Affiliation(s)
- Ling Bai
- Department of Nephrology and Rheumatology, Children's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, China
| | - Jing Zhuang
- Division of Nephrology, Department of Internal Medicine, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, China
| | - Changrong Zhang
- Division of Nephrology, Department of Internal Medicine, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, China
| | - Chen Lu
- Division of Nephrology, Department of Internal Medicine, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Xuefei Tian
- Section of Nephrology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Hong Jiang
- Division of Nephrology, Department of Internal Medicine, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, China
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42
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Schneider R, Deutsch K, Hoeprich GJ, Marquez J, Hermle T, Braun DA, Seltzsam S, Kitzler TM, Mao Y, Buerger F, Majmundar AJ, Onuchic-Whitford AC, Kolvenbach CM, Schierbaum L, Schneider S, Halawi AA, Nakayama M, Mann N, Connaughton DM, Klämbt V, Wagner M, Riedhammer KM, Renders L, Katsura Y, Thumkeo D, Soliman NA, Mane S, Lifton RP, Shril S, Khokha MK, Hoefele J, Goode BL, Hildebrandt F. DAAM2 Variants Cause Nephrotic Syndrome via Actin Dysregulation. Am J Hum Genet 2020; 107:1113-1128. [PMID: 33232676 DOI: 10.1016/j.ajhg.2020.11.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 11/05/2020] [Indexed: 01/10/2023] Open
Abstract
The discovery of >60 monogenic causes of nephrotic syndrome (NS) has revealed a central role for the actin regulators RhoA/Rac1/Cdc42 and their effectors, including the formin INF2. By whole-exome sequencing (WES), we here discovered bi-allelic variants in the formin DAAM2 in four unrelated families with steroid-resistant NS. We show that DAAM2 localizes to the cytoplasm in podocytes and in kidney sections. Further, the variants impair DAAM2-dependent actin remodeling processes: wild-type DAAM2 cDNA, but not cDNA representing missense variants found in individuals with NS, rescued reduced podocyte migration rate (PMR) and restored reduced filopodia formation in shRNA-induced DAAM2-knockdown podocytes. Filopodia restoration was also induced by the formin-activating molecule IMM-01. DAAM2 also co-localizes and co-immunoprecipitates with INF2, which is intriguing since variants in both formins cause NS. Using in vitro bulk and TIRF microscopy assays, we find that DAAM2 variants alter actin assembly activities of the formin. In a Xenopus daam2-CRISPR knockout model, we demonstrate actin dysregulation in vivo and glomerular maldevelopment that is rescued by WT-DAAM2 mRNA. We conclude that DAAM2 variants are a likely cause of monogenic human SRNS due to actin dysregulation in podocytes. Further, we provide evidence that DAAM2-associated SRNS may be amenable to treatment using actin regulating compounds.
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43
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Wang Y, Pedigo CE, Inoue K, Tian X, Cross E, Ebenezer K, Li W, Wang Z, Shin JW, Schwartze E, Groener M, Ishibe S. Murine Epsins Play an Integral Role in Podocyte Function. J Am Soc Nephrol 2020; 31:2870-2886. [PMID: 33051360 PMCID: PMC7790213 DOI: 10.1681/asn.2020050691] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 08/30/2020] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Epsins, a family of evolutionarily conserved membrane proteins, play an essential role in endocytosis and signaling in podocytes. METHODS Podocyte-specific Epn1, Epn2, Epn3 triple-knockout mice were generated to examine downstream regulation of serum response factor (SRF) by cell division control protein 42 homolog (Cdc42). RESULTS Podocyte-specific loss of epsins resulted in increased albuminuria and foot process effacement. Primary podocytes isolated from these knockout mice exhibited abnormalities in cell adhesion and spreading, which may be attributed to reduced activation of cell division control protein Cdc42 and SRF, resulting in diminished β1 integrin expression. In addition, podocyte-specific loss of Srf resulted in severe albuminuria and foot process effacement, and defects in cell adhesion and spreading, along with decreased β1 integrin expression. CONCLUSIONS Epsins play an indispensable role in maintaining properly functioning podocytes through the regulation of Cdc42 and SRF-dependent β1 integrin expression.
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Affiliation(s)
- Ying Wang
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
- Centre for Evidence-Based Chinese Medicine, Beijing University of Chinese Medicine, Chaoyang District, Beijing, 100029, China
| | - Christopher E Pedigo
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Kazunori Inoue
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Xuefei Tian
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Elizabeth Cross
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Karen Ebenezer
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Wei Li
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Zhen Wang
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Jee Won Shin
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Eike Schwartze
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Marwin Groener
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Shuta Ishibe
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
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44
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Tian X, Inoue K, Zhang Y, Wang Y, Sperati CJ, Pedigo CE, Zhao T, Yan M, Groener M, Moledina DG, Ebenezer K, Li W, Zhang Z, Liebermann DA, Greene L, Greer P, Parikh CR, Ishibe S. Inhibiting calpain 1 and 2 in cyclin G associated kinase-knockout mice mitigates podocyte injury. JCI Insight 2020; 5:142740. [PMID: 33208557 PMCID: PMC7710277 DOI: 10.1172/jci.insight.142740] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/08/2020] [Indexed: 12/27/2022] Open
Abstract
Evidence for reduced expression of cyclin G associated kinase (GAK) in glomeruli of patients with chronic kidney disease was observed in the Nephroseq human database, and GAK was found to be associated with the decline in kidney function. To examine the role of GAK, a protein that functions to uncoat clathrin during endocytosis, we generated podocyte-specific Gak-knockout mice (Gak-KO), which developed progressive proteinuria and kidney failure with global glomerulosclerosis. We isolated glomeruli from the mice carrying the mutation to perform messenger RNA profiling and unearthed evidence for dysregulated podocyte calpain protease activity as an important contributor to progressive podocyte damage. Treatment with calpain inhibitor III specifically inhibited calpain-1/-2 activities, mitigated the degree of proteinuria and glomerulosclerosis, and led to a striking increase in survival in the Gak-KO mice. Podocyte-specific deletion of Capns1, essential for calpain-1 and calpain-2 activities, also improved proteinuria and glomerulosclerosis in Gak-KO mice. Increased podocyte calpain activity-mediated proteolysis of IκBα resulted in increased NF-κB p65-induced expression of growth arrest and DNA-damage-inducible 45 beta in the Gak-KO mice. Our results suggest that loss of podocyte-associated Gak induces glomerular injury secondary to calcium dysregulation and aberrant calpain activation, which when inhibited, can provide a protective role.
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MESH Headings
- Animals
- Calpain/antagonists & inhibitors
- Diabetic Nephropathies/etiology
- Diabetic Nephropathies/metabolism
- Diabetic Nephropathies/pathology
- Diabetic Nephropathies/therapy
- Female
- Glomerulosclerosis, Focal Segmental/etiology
- Glomerulosclerosis, Focal Segmental/metabolism
- Glomerulosclerosis, Focal Segmental/pathology
- Glomerulosclerosis, Focal Segmental/therapy
- Humans
- Intracellular Signaling Peptides and Proteins/genetics
- Intracellular Signaling Peptides and Proteins/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Podocytes/metabolism
- Podocytes/pathology
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/metabolism
- Protein Serine-Threonine Kinases/physiology
- Renal Insufficiency, Chronic/etiology
- Renal Insufficiency, Chronic/metabolism
- Renal Insufficiency, Chronic/pathology
- Renal Insufficiency, Chronic/therapy
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Affiliation(s)
- Xuefei Tian
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Kazunori Inoue
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Yan Zhang
- State Key Laboratory of Organ Failure Research, Southern Medical University, Nanfang Hospital, Guangzhou, China
- Center for Bioinformatics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Ying Wang
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - C. John Sperati
- Division of Nephrology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Christopher E. Pedigo
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Tingting Zhao
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Meihua Yan
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Marwin Groener
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Dennis G. Moledina
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Karen Ebenezer
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Wei Li
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Zhenhai Zhang
- State Key Laboratory of Organ Failure Research, Southern Medical University, Nanfang Hospital, Guangzhou, China
- Center for Bioinformatics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Dan A. Liebermann
- Fels Institute of Cancer Research and Molecular Biology and Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania USA
| | - Lois Greene
- Laboratory of Cell Biology, National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland, USA
| | - Peter Greer
- Queen’s Cancer Research Institute, Kingston, Ontario, Canada
| | - Chirag R. Parikh
- Division of Nephrology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Shuta Ishibe
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
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45
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Wang Q, Tian X, Zhou W, Wang Y, Zhao H, Li J, Zhou X, Zhang H, Zhao T, Li P. Protective Role of Tangshen Formula on the Progression of Renal Damage in db/db Mice by TRPC6/Talin1 Pathway in Podocytes. J Diabetes Res 2020; 2020:3634974. [PMID: 33015191 PMCID: PMC7519445 DOI: 10.1155/2020/3634974] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 08/11/2020] [Accepted: 08/29/2020] [Indexed: 12/16/2022] Open
Abstract
Tangshen Formula (TSF) is a Chinese Medicine formula that has been reported to alleviate proteinuria and protect renal function in humans and animals with diabetic kidney disease (DKD). However, little is known about its mechanism in improving proteinuria. The dysregulation of podocyte cell-matrix adhesion has been demonstrated to play an important role in the pathogenesis and progression of proteinuric kidney diseases including DKD. In the present study, the underlying protective mechanism of TSF on podocytes was investigated using the murine model of type 2 DKD db/db mice in vivo and advanced glycation end products (AGEs)-stimulated primary mice podocytes in vitro. Results revealed that TSF treatment could significantly mitigate reduction of podocyte numbers and foot process effacement, reduce proteinuria, and protect renal function in db/db mice. There was a significant increase in expression of transient receptor potential canonical channel 6 (TRPC6) and a decrease in expression of talin1 in podocytes of db/db mice. The results of AGEs-stimulated primary mice podocytes showed increased cell migration and actin-cytoskeleton rearrangement. Moreover, primary mice podocytes stimulated by AGEs displayed an increase in TRPC6-dependent Ca2+ influx, a loss of talin1, and translocation of nuclear factor of activated T cell (NFATC) 2. These dysregulations in mice primary podocytes stimulated by AGEs could be significantly attenuated after TSF treatment. 1-Oleoyl-2-acetyl-sn-glycerol (OAG), a TRPC6 agonist, blocked the protective role of TSF on podocyte cell-matrix adherence. In conclusion, TSF could protect podocytes from injury and reduce proteinuria in DKD, which may be mediated by the regulation of the TRPC6/Talin1 pathway in podocytes.
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Affiliation(s)
- Qian Wang
- Beijing University of Chinese Medicine, Beijing 100029, China
- Beijing Key Laboratory for Immune-Mediated Inflammatory Diseases, Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, China
| | - Xuefei Tian
- Section of Nephrology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Wei'e Zhou
- Beijing Key Laboratory for Immune-Mediated Inflammatory Diseases, Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, China
| | - Yan Wang
- Beijing Key Laboratory of Diabetes Research and Care, Center for Endocrine Metabolism and Immune Diseases, Lu He Hospital, Capital Medical University, Beijing 101149, China
| | - Hailing Zhao
- Beijing Key Laboratory for Immune-Mediated Inflammatory Diseases, Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, China
| | - Jialin Li
- Beijing University of Chinese Medicine, Beijing 100029, China
- Beijing Key Laboratory for Immune-Mediated Inflammatory Diseases, Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, China
| | - Xuefeng Zhou
- Beijing University of Chinese Medicine, Beijing 100029, China
- Beijing Key Laboratory for Immune-Mediated Inflammatory Diseases, Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, China
| | - Haojun Zhang
- Beijing Key Laboratory for Immune-Mediated Inflammatory Diseases, Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, China
| | - Tingting Zhao
- Beijing Key Laboratory for Immune-Mediated Inflammatory Diseases, Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, China
| | - Ping Li
- Beijing Key Laboratory for Immune-Mediated Inflammatory Diseases, Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, China
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Ning L, Suleiman HY, Miner JH. Synaptopodin Is Dispensable for Normal Podocyte Homeostasis but Is Protective in the Context of Acute Podocyte Injury. J Am Soc Nephrol 2020; 31:2815-2832. [PMID: 32938649 DOI: 10.1681/asn.2020050572] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 07/27/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Synaptopodin (Synpo) is an actin-associated protein in podocytes and dendritic spines. Many functions in regulating the actin cytoskeleton via RhoA and other pathways have been ascribed to Synpo, yet no pathogenic mutations in the SYNPO gene have been discovered in patients. Naturally occurring Synpo isoforms are known (Synpo-short and -long), and a novel truncated version (Synpo-T) is upregulated in podocytes from Synpo mutant mice. Synpo-T maintains some Synpo functions, which may prevent a podocyte phenotype from emerging in unchallenged mutant mice. METHODS Novel mouse models were generated to further investigate the functions of Synpo. In one, CRISPR/Cas9 deleted most of the Synpo gene, preventing production of any detectable Synpo protein. Two other mutant strains made truncated versions of the protein. Adriamycin injections were used to challenge the mice, and Synpo functions were investigated in primary cultured podocytes. RESULTS Mice that could not make detectable Synpo (Synpo -/- ) did not develop any kidney abnormalities up to 12 months of age. However, Synpo -/- mice were more susceptible to Adriamycin nephropathy. In cultured primary podocytes from mutant mice, the absence of Synpo caused loss of stress fibers, increased the number and size of focal adhesions, and impaired cell migration. Furthermore, loss of Synpo led to decreased RhoA activity and increased Rac1 activation. CONCLUSIONS In contrast to previous findings, podocytes can function normally in vivo in the absence of any Synpo isoform. Synpo plays a protective role in the context of podocyte injury through its involvement in actin reorganization and focal adhesion dynamics.
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Affiliation(s)
- Liang Ning
- Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri
| | - Hani Y Suleiman
- Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri
| | - Jeffrey H Miner
- Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri
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Nagayama Y, Isoo N, Nakashima A, Suzuki K, Yamano M, Nariyama T, Yagame M, Matsui K. Renoprotective effects of paramylon, a β-1,3-D-Glucan isolated from Euglena gracilis Z in a rodent model of chronic kidney disease. PLoS One 2020; 15:e0237086. [PMID: 32764782 PMCID: PMC7413521 DOI: 10.1371/journal.pone.0237086] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 07/20/2020] [Indexed: 12/25/2022] Open
Abstract
Paramylon is a novel β-glucan that is stored by Euglena gracilis Z, which is a unicellular photosynthesizing green alga with characteristics of both animals and plants. Recent studies have indicated that paramylon functions as an immunomodulator or a dietary fiber. Currently, chronic kidney disease (CKD) is a global health problem, and there is no effective preventive treatment for CKD progression. However, paramylon may suppress the progression of CKD via the elimination of uremic toxins or modulation of gut microbiota, leading to the alleviation of inflammation. The aim of this study was to evaluate the effect of paramylon in CKD rat model. Eight-week-old male Wistar rats with a 5/6 nephrectomy were given either a normal diet or a diet containing 5% paramylon for 8 weeks. Proteinuria was measured intermittently. Serum and kidney tissues were harvested after sacrifice. We performed a renal molecular and histopathological investigation, serum metabolome analysis, and gut microbiome analysis. The results showed that paramylon attenuated renal function, glomerulosclerosis, tubulointerstitial injury, and podocyte injury in the CKD rat model. Renal fibrosis, tubulointerstitial inflammatory cell infiltration, and proinflammatory cytokine gene expression levels tended to be suppressed with paramylon treatment. Further, paramylon inhibited the accumulation of uremic toxins, including tricarboxylic acid (TCA) cycle-related metabolites and modulated a part of CKD-related gut microbiota in the CKD rat model. In conclusion, we suggest that paramylon mainly inhibited the absorption of non-microbiota-derived uremic solutes, leading to protect renal injury via anti-inflammatory and anti-fibrotic effects. Paramylon may be a novel compound that can act against CKD progression.
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Affiliation(s)
- Yoshikuni Nagayama
- Department of Internal Medicine IV, Teikyo University School of Medicine, University Hospital, Mizonokuchi, Kawasaki, Japan
- * E-mail:
| | - Naoyuki Isoo
- Department of Internal Medicine IV, Teikyo University School of Medicine, University Hospital, Mizonokuchi, Kawasaki, Japan
| | | | | | - Mizuki Yamano
- Department of Internal Medicine IV, Teikyo University School of Medicine, University Hospital, Mizonokuchi, Kawasaki, Japan
| | - Tomoyuki Nariyama
- Department of Internal Medicine IV, Teikyo University School of Medicine, University Hospital, Mizonokuchi, Kawasaki, Japan
| | - Motoka Yagame
- Department of Internal Medicine IV, Teikyo University School of Medicine, University Hospital, Mizonokuchi, Kawasaki, Japan
| | - Katsuyuki Matsui
- Department of Internal Medicine IV, Teikyo University School of Medicine, University Hospital, Mizonokuchi, Kawasaki, Japan
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Blaine J, Dylewski J. Regulation of the Actin Cytoskeleton in Podocytes. Cells 2020; 9:cells9071700. [PMID: 32708597 PMCID: PMC7408282 DOI: 10.3390/cells9071700] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 06/30/2020] [Accepted: 07/07/2020] [Indexed: 12/13/2022] Open
Abstract
Podocytes are an integral part of the glomerular filtration barrier, a structure that prevents filtration of large proteins and macromolecules into the urine. Podocyte function is dependent on actin cytoskeleton regulation within the foot processes, structures that link podocytes to the glomerular basement membrane. Actin cytoskeleton dynamics in podocyte foot processes are complex and regulated by multiple proteins and other factors. There are two key signal integration and structural hubs within foot processes that regulate the actin cytoskeleton: the slit diaphragm and focal adhesions. Both modulate actin filament extension as well as foot process mobility. No matter what the initial cause, the final common pathway of podocyte damage is dysregulation of the actin cytoskeleton leading to foot process retraction and proteinuria. Disruption of the actin cytoskeleton can be due to acquired causes or to genetic mutations in key actin regulatory and signaling proteins. Here, we describe the major structural and signaling components that regulate the actin cytoskeleton in podocytes as well as acquired and genetic causes of actin dysregulation.
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Affiliation(s)
- Judith Blaine
- Renal Division, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA;
| | - James Dylewski
- Renal Division, University of Colorado Anschutz Medical Campus and Denver Health Medical Center, Aurora, CO 80045, USA
- Correspondence: ; Tel.: +303-724-4841
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Groener M, Wang Y, Cross E, Tian X, Ebenezer K, Baik E, Pedigo C, Schiffer M, Inoue K, Ishibe S. Identification of Podocyte Cargo Proteins by Proteomic Analysis of Clathrin-Coated Vesicles. KIDNEY360 2020; 1:480-490. [PMID: 35368594 PMCID: PMC8809311 DOI: 10.34067/kid.0000212020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 04/13/2020] [Indexed: 04/20/2023]
Abstract
Background Clathrin-mediated endocytosis (CME) plays a fundamental role in podocyte health. Genetic ablation of genes implicated in CME has been shown to cause severe proteinuria and foot process effacement in mice. However, little is known about the cargo of clathrin-coated vesicles (CCVs) in podocytes. The goal of this study was to isolate CCVs from podocytes and identify their cargo by proteomic analysis. Methods Glomeruli isolated from Podocin-Cre Rosa-DTRflox mouse kidneys were seeded and treated with diphtheria toxin to obtain pure primary podocyte cultures. CCVs were isolated by differential gradient ultracentrifugation, and enrichment of CCVs was assessed by immunoblotting and electron microscopy (EM). Liquid chromatography-mass spectrometry (LC-MS) was performed for proteomic analysis. Proteins with higher abundance than transferrin receptor protein 1 were evaluated for CCV cargo potential against previously published literature. Immunofluorescence staining of identified cargo proteins and CCVs was performed in podocytes for further verification. Results Immunoblotting for multiple protein markers of CME revealed enrichment in the CCV fraction. Enrichment of CCVs among other small vesicles was observed via EM. Proteomics yielded a total of >1200 significant proteins. Multiple-step data analysis revealed 36 CCV-associated proteins, of which 10 represent novel, highly abundant cargo proteins in podocytes. Colocalization of cargo proteins and CCVs on immunostaining was observed. Conclusions Our identification of podocyte CCV cargo proteins helps to elucidate the importance of endocytic trafficking for podocyte health and maintenance of the glomerular environment.
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Affiliation(s)
- Marwin Groener
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
- Department of Nephrology and Hypertension, University Hospital Erlangen, Erlangen, Germany
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Ying Wang
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Elizabeth Cross
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Xuefei Tian
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Karen Ebenezer
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Eunice Baik
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Christopher Pedigo
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Mario Schiffer
- Department of Nephrology and Hypertension, University Hospital Erlangen, Erlangen, Germany
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
- Mount Desert Island Biological Laboratories, Salisbury Cove, Maine
| | - Kazunori Inoue
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Shuta Ishibe
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
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tRNA-Derived Fragments in Podocytes with Adriamycin-Induced Injury Reveal the Potential Mechanism of Idiopathic Nephrotic Syndrome. BIOMED RESEARCH INTERNATIONAL 2020; 2020:7826763. [PMID: 32685525 PMCID: PMC7330628 DOI: 10.1155/2020/7826763] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/12/2020] [Accepted: 05/29/2020] [Indexed: 11/17/2022]
Abstract
Idiopathic nephrotic syndrome (INS) is a disease involving injury to podocytes in the glomerular filtration barrier, and its specific causes have not been elucidated. Transfer RNA-derived fragments (tRFs), products of precise tRNA cleavage, have been indicated to play critical roles in various diseases. Currently, there is no relevant research on the role of tRFs in INS. This study intends to explore the changes in and importance of tRFs during podocyte injury in vitro and to further analyze the potential mechanism of INS. Differentially expressed tRFs in the adriamycin-treated group were identified by high-throughput sequencing and further verified by quantitative RT-PCR. In total, 203 tRFs with significant differential expression were identified, namely, 102 upregulated tRFs and 101 downregulated tRFs (q < 0.05, ∣log2FC | ≥2). In particular, AS-tDR-008924, AS-tDR-011690, tDR-003634, AS-tDR-013354, tDR-011031, AS-tDR-001008, and AS-tDR-007319 were predicted to be involved in podocyte injury by targeting the Gpr, Wnt, Rac1, and other genes. Furthermore, gene ontology analysis showed that these differential tRFs were strongly associated with podocyte injury processes such as protein binding, cell adhesion, synapses, the actin cytoskeleton, and insulin-activate receptor activity. KEGG pathway analysis predicted that they participated in the PI3K-Akt signaling pathway, Wnt signaling pathway, and Ras signaling pathway. It was reported that these pathways contribute to podocyte injury. In conclusion, our study revealed that changes in the expression levels of tRFs might be involved in INS. Seven of the differentially expressed tRFs might play important roles in the process of podocyte injury and are worthy of further study.
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