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Xi G, Lamba SA, Mysh M, Poulton JS. Oxidative Stress Contributes to Slit Diaphragm Defects Caused by Disruption of Endocytosis. Kidney Int Rep 2024; 9:451-463. [PMID: 38344712 PMCID: PMC10851022 DOI: 10.1016/j.ekir.2023.11.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 10/27/2023] [Accepted: 11/20/2023] [Indexed: 03/04/2024] Open
Abstract
Introduction Podocyte slit diaphragms are an important component of the glomerular filtration barrier. Podocyte injury frequently includes defects in slit diaphragms, and various mechanisms for these defects have been described, including altered endocytic trafficking of slit diaphragm proteins or oxidative stress. However, the potential relationship between endocytosis and oxidative stress in the context of slit diaphragm integrity has not been extensively considered. Methods To examine the potential relationships between endocytosis, oxidative stress, and slit diaphragm integrity, we induced genetic or pharmacological disruption of endocytosis in Drosophila nephrocytes (the insect orthologue of podocytes) and cultured human podocytes. We then employed immunofluorescence microscopy to analyze protein localization and levels, and to quantify signal from reactive oxygen species (ROS) dyes. Immunoprecipitation from podocyte cell lysates was used to examine effects on slit diaphragm protein complex formation (i.e., nephrin/podocin and nephrin/ZO-1). Results Disruption of endocytosis in nephrocytes and podocytes led to slit diaphragm defects, elevated levels of ROS (oxidative stress), and activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant pathway. In nephrocytes with defective endocytosis, perturbation of Nrf2 signaling exacerbated slit diaphragm defects. Conversely, overexpression of Nrf2 target genes catalase or glucose-6-phosphate dehydrogenase (G6PD) significantly ameliorated slit diaphragm defects caused by disruption of endocytosis. Conclusion Oxidative stress is an important consequence of defective endocytosis and contributes to the defects in slit diaphragm integrity associated with disruption of endocytic trafficking.
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Affiliation(s)
- Gang Xi
- UNC Kidney Center, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Sajan A. Lamba
- UNC Kidney Center, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Michael Mysh
- UNC Kidney Center, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - John S. Poulton
- UNC Kidney Center, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Zhang J, Jiang Z, Chen C, Yao L, Gao Z, Cheng Z, Yan Y, Liu H, Shi A. Age-associated decline in RAB-10 efficacy impairs intestinal barrier integrity. NATURE AGING 2023; 3:1107-1127. [PMID: 37640905 DOI: 10.1038/s43587-023-00475-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 07/24/2023] [Indexed: 08/31/2023]
Abstract
The age-related decline in the ability of the intestinal barrier to maintain selective permeability can lead to various physiological disturbances. Adherens junctions play a vital role in regulating intestinal permeability, and their proper assembly is contingent upon endocytic recycling. However, how aging affects the recycling efficiency and, consequently, the integrity of adherens junctions remains unclear. Here we show that RAB-10/Rab10 functionality is reduced during senescence, leading to impaired adherens junctions in the Caenorhabditis elegans intestine. Mechanistic analysis reveals that SDPN-1/PACSINs is upregulated in aging animals, suppressing RAB-10 activation by competing with DENN-4/GEF. Consistently, SDPN-1 knockdown alleviates age-related abnormalities in adherens junction integrity and intestinal barrier permeability. Of note, the inhibitory effect of SDPN-1 on RAB-10 requires KGB-1/JUN kinase, which presumably enhances the potency of SDPN-1 by altering its oligomerization state. Together, by examining age-associated changes in endocytic recycling, our study sheds light on how aging can impact intestinal barrier permeability.
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Affiliation(s)
- Jing Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology, Wuhan, China
| | - Zongyan Jiang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology, Wuhan, China
| | - Changling Chen
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology, Wuhan, China
| | - Longfeng Yao
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology, Wuhan, China
| | - Ziwei Gao
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology, Wuhan, China
| | - Zihang Cheng
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology, Wuhan, China
| | - Yanling Yan
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology, Wuhan, China
| | - Hang Liu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology, Wuhan, China.
| | - Anbing Shi
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology, Wuhan, China.
- Cell Architecture Research Center, Huazhong University of Science and Technology, Wuhan, China.
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Bouslama R, Dumont V, Lindfors S, Paavolainen L, Tienari J, Nisen H, Mirtti T, Saleem MA, Gordin D, Groop PH, Suetsugu S, Lehtonen S. Phosphorylation of PACSIN2 at S313 Regulates Podocyte Architecture in Coordination with N-WASP. Cells 2023; 12:1487. [PMID: 37296607 PMCID: PMC10252800 DOI: 10.3390/cells12111487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 05/16/2023] [Accepted: 05/23/2023] [Indexed: 06/12/2023] Open
Abstract
Changes in the dynamic architecture of podocytes, the glomerular epithelial cells, lead to kidney dysfunction. Previous studies on protein kinase C and casein kinase 2 substrates in neurons 2 (PACSIN2), a known regulator of endocytosis and cytoskeletal organization, reveal a connection between PACSIN2 and kidney pathogenesis. Here, we show that the phosphorylation of PACSIN2 at serine 313 (S313) is increased in the glomeruli of rats with diabetic kidney disease. We found that phosphorylation at S313 is associated with kidney dysfunction and increased free fatty acids rather than with high glucose and diabetes alone. Phosphorylation of PACSIN2 emerged as a dynamic process that fine-tunes cell morphology and cytoskeletal arrangement, in cooperation with the regulator of the actin cytoskeleton, Neural Wiskott-Aldrich syndrome protein (N-WASP). PACSIN2 phosphorylation decreased N-WASP degradation while N-WASP inhibition triggered PACSIN2 phosphorylation at S313. Functionally, pS313-PACSIN2 regulated actin cytoskeleton rearrangement depending on the type of cell injury and the signaling pathways involved. Collectively, this study indicates that N-WASP induces phosphorylation of PACSIN2 at S313, which serves as a mechanism whereby cells regulate active actin-related processes. The dynamic phosphorylation of S313 is needed to regulate cytoskeletal reorganization.
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Affiliation(s)
- Rim Bouslama
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | - Vincent Dumont
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | - Sonja Lindfors
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | - Lassi Paavolainen
- Institute for Molecular Medicine Finland (FIMM), Helsinki Institute of Life Science (HiLIFE), University of Helsinki, 00290 Helsinki, Finland
| | - Jukka Tienari
- Department of Pathology, University of Helsinki, Helsinki, and Helsinki University Hospital, 05850 Hyvinkää, Finland
| | - Harry Nisen
- Department of Urology, Helsinki University Hospital, 00029 HUS, Finland
| | - Tuomas Mirtti
- Department of Pathology, Helsinki University Hospital, 00290 Helsinki, Finland
- Research Program in Systems Oncology, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | - Moin A. Saleem
- Children’s Renal Unit, Bristol Medical School, University of Bristol, Bristol BS8 1TS, UK
| | - Daniel Gordin
- Minerva Foundation Institute for Medical Research, 00290 Helsinki, Finland
- Abdominal Center, Nephrology, University of Helsinki and Helsinki University Hospital, 00290 Helsinki, Finland
- Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA
| | - Per-Henrik Groop
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, 00290 Helsinki, Finland
- Department of Nephrology, University of Helsinki, Helsinki, and Helsinki University Hospital, 00290 Helsinki, Finland
- Department of Diabetes, Central Clinical School, Monash University, Melbourne, VIC 3800, Australia
| | - Shiro Suetsugu
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0192, Japan
- Data Science Center, Nara Institute of Science and Technology, Ikoma 630-0192, Japan
- Center for Digital Green-Innovation, Nara Institute of Science and Technology, Ikoma 630-0192, Japan
| | - Sanna Lehtonen
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
- Department of Pathology, University of Helsinki, 00290 Helsinki, Finland
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Sun H, Weidner J, Allamargot C, Piper RC, Misurac J, Nester C. Dynein-Mediated Trafficking: A New Mechanism of Diabetic Podocytopathy. KIDNEY360 2023; 4:162-176. [PMID: 36821608 PMCID: PMC10103215 DOI: 10.34067/kid.0006852022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022]
Abstract
Key Points The expression of dynein is increased in human and rodent models of diabetic nephropathy (DN), eliciting a new dynein-driven pathogenesis. Uncontrolled dynein impairs the molecular sieve of kidney by remodeling the postendocytic triage and homeostasis of nephrin. The delineation of the dynein-driven pathogenesis promises a broad spectrum of new therapeutic targets for human DN. Background Diabetic nephropathy (DN) is characterized by increased endocytosis and degradation of nephrin, a protein that comprises the molecular sieve of the glomerular filtration barrier. While nephrin internalization has been found activated in diabetes-stressed podocytes, the postinternalization trafficking steps that lead to the eventual depletion of nephrin and the development of DN are unclear. Our work on an inherited podocytopathy uncovered that dysregulated dynein could compromise nephrin trafficking, leading us to test whether and how dynein mediates the pathogenesis of DN. Methods We analyzed the transcription of dynein components in public DN databases, using the Nephroseq platform. We verified altered dynein transcription in diabetic podocytopathy by quantitative PCR. Dynein-mediated trafficking and degradation of nephrin was investigated using an in vitro nephrin trafficking model and was demonstrated in a mouse model with streptozotocin (STZ)-induced DN and in human kidney biopsy sections. Results Our transcription analysis revealed increased expression of dynein in human DN and diabetic mouse kidney, correlated significantly with the severity of hyperglycemia and DN. In diabetic podocytopathy, we observed that dynein-mediated postendocytic sorting of nephrin was upregulated, resulting in accelerated nephrin degradation and disrupted nephrin recycling. In hyperglycemia-stressed podocytes, Dynll1 , one of the most upregulated dynein components, is required for the recruitment of dynein complex that mediates the postendocytic sorting of nephrin. This was corroborated by observing enhanced Dynll1-nephrin colocalization in podocytes of diabetic patients, as well as dynein-mediated trafficking and degradation of nephrin in STZ-induced diabetic mice with hyperglycemia. Knockdown of Dynll1 attenuated lysosomal degradation of nephrin and promoted its recycling, suggesting the essential role of Dynll1 in dynein-mediated mistrafficking. Conclusions Our studies show that hyperglycemia stimulates dynein-mediated trafficking of nephrin to lysosomes by inducing its expression. The decoding of dynein-driven pathogenesis of diabetic podocytopathy offers a spectrum of new dynein-related therapeutic targets for DN.
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Affiliation(s)
- Hua Sun
- Division of Nephrology, Stead Family Department of Pediatrics, The University of Iowa, Iowa City, Iowa
- Carver College of Medicine, The University of Iowa, Iowa City, Iowa
| | - Jillian Weidner
- Division of Nephrology, Stead Family Department of Pediatrics, The University of Iowa, Iowa City, Iowa
- Carver College of Medicine, The University of Iowa, Iowa City, Iowa
| | - Chantal Allamargot
- Central Microscopy Research Facility, The University of Iowa, Iowa City, Iowa
| | - Robert C. Piper
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, The University of Iowa, Iowa City, Iowa
| | - Jason Misurac
- Division of Nephrology, Stead Family Department of Pediatrics, The University of Iowa, Iowa City, Iowa
- Carver College of Medicine, The University of Iowa, Iowa City, Iowa
| | - Carla Nester
- Division of Nephrology, Stead Family Department of Pediatrics, The University of Iowa, Iowa City, Iowa
- Carver College of Medicine, The University of Iowa, Iowa City, Iowa
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Popov LD. Deciphering the relationship between caveolae-mediated intracellular transport and signalling events. Cell Signal 2022; 97:110399. [PMID: 35820545 DOI: 10.1016/j.cellsig.2022.110399] [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: 05/30/2022] [Revised: 07/02/2022] [Accepted: 07/05/2022] [Indexed: 11/30/2022]
Abstract
The caveolae-mediated transport across polarized epithelial cell barriers has been largely deciphered in the last decades and is considered the second essential intracellular transfer mechanism, after the clathrin-dependent endocytosis. The basic cell biology knowledge was supplemented recently, with the molecular mechanisms beyond caveolae generation implying the key contribution of the lipid-binding proteins (the structural protein Caveolin and the adapter protein Cavin), along with the bulb coat stabilizing molecules PACSIN-2 and Eps15 homology domain protein-2. The current attention is focused also on caveolae architecture (such as the bulb coat, the neck, the membrane funnel inside the bulb, and the associated receptors), and their specific tasks during the intracellular transport of various cargoes. Here, we resume the present understanding of the assembly, detachment, and internalization of caveolae from the plasma membrane lipid raft domains, and give an updated view on transcytosis and endocytosis, the two itineraries of cargoes transport via caveolae. The review adds novel data on the signalling molecules regulating caveolae intracellular routes and on the transport dysregulation in diseases. The therapeutic possibilities offered by exploitation of Caveolin-1 expression and caveolae trafficking, and the urgent issues to be uncovered conclude the review.
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Affiliation(s)
- Lucia-Doina Popov
- Institute of Cellular Biology and Pathology "Nicolae Simionescu" of the Romanian Academy, 8, B.P. Hasdeu Street, 050568 Bucharest, Romania.
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6
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Dumont V, Lehtonen S. PACSIN proteins in vivo: Roles in development and physiology. Acta Physiol (Oxf) 2022; 234:e13783. [PMID: 34990060 PMCID: PMC9285741 DOI: 10.1111/apha.13783] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 11/15/2021] [Accepted: 01/01/2022] [Indexed: 12/22/2022]
Abstract
Protein kinase C and casein kinase substrate in neurons (PACSINs), or syndapins (synaptic dynamin‐associated proteins), are a family of proteins involved in the regulation of cell cytoskeleton, intracellular trafficking and signalling. Over the last twenty years, PACSINs have been mostly studied in the in vitro and ex vivo settings, and only in the last decade reports on their function in vivo have emerged. We first summarize the identification, structure and cellular functions of PACSINs, and then focus on the relevance of PACSINs in vivo. During development in various model organisms, PACSINs participate in diverse processes, such as neural crest cell development, gastrulation, laterality development and neuromuscular junction formation. In mouse, PACSIN2 regulates angiogenesis during retinal development and in human, PACSIN2 associates with monosomy and embryonic implantation. In adulthood, PACSIN1 has been extensively studied in the brain and shown to regulate neuromorphogenesis, receptor trafficking and synaptic plasticity. Several genetic studies suggest a role for PACSIN1 in the development of schizophrenia, which is also supported by the phenotype of mice depleted of PACSIN1. PACSIN2 plays an essential role in the maintenance of intestinal homeostasis and participates in kidney repair processes after injury. PACSIN3 is abundant in muscle tissue and necessary for caveolar biogenesis to create membrane reservoirs, thus controlling muscle function, and has been linked to certain genetic muscular disorders. The above examples illustrate the importance of PACSINs in diverse physiological or tissue repair processes in various organs, and associations to diseases when their functions are disturbed.
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Affiliation(s)
- Vincent Dumont
- Department of Pathology and Research Program for Clinical and Molecular Metabolism Faculty of Medicine University of Helsinki Helsinki Finland
| | - Sanna Lehtonen
- Department of Pathology and Research Program for Clinical and Molecular Metabolism Faculty of Medicine University of Helsinki Helsinki Finland
- Department of Pathology University of Helsinki Helsinki Finland
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7
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Wu H, Norton V, Cui K, Zhu B, Bhattacharjee S, Lu YW, Wang B, Shan D, Wong S, Dong Y, Chan SL, Cowan D, Xu J, Bielenberg DR, Zhou C, Chen H. Diabetes and Its Cardiovascular Complications: Comprehensive Network and Systematic Analyses. Front Cardiovasc Med 2022; 9:841928. [PMID: 35252405 PMCID: PMC8891533 DOI: 10.3389/fcvm.2022.841928] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 01/18/2022] [Indexed: 12/12/2022] Open
Abstract
Diabetes mellitus is a worldwide health problem that usually comes with severe complications. There is no cure for diabetes yet and the threat of these complications is what keeps researchers investigating mechanisms and treatments for diabetes mellitus. Due to advancements in genomics, epigenomics, proteomics, and single-cell multiomics research, considerable progress has been made toward understanding the mechanisms of diabetes mellitus. In addition, investigation of the association between diabetes and other physiological systems revealed potentially novel pathways and targets involved in the initiation and progress of diabetes. This review focuses on current advancements in studying the mechanisms of diabetes by using genomic, epigenomic, proteomic, and single-cell multiomic analysis methods. It will also focus on recent findings pertaining to the relationship between diabetes and other biological processes, and new findings on the contribution of diabetes to several pathological conditions.
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Affiliation(s)
- Hao Wu
- Department of Surgery, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital, Boston, MA, United States
| | - Vikram Norton
- Department of Surgery, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital, Boston, MA, United States
| | - Kui Cui
- Department of Surgery, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital, Boston, MA, United States
| | - Bo Zhu
- Department of Surgery, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital, Boston, MA, United States
| | - Sudarshan Bhattacharjee
- Department of Surgery, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital, Boston, MA, United States
| | - Yao Wei Lu
- Department of Surgery, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital, Boston, MA, United States
| | - Beibei Wang
- Department of Surgery, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital, Boston, MA, United States
| | - Dan Shan
- Department of Surgery, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital, Boston, MA, United States
| | - Scott Wong
- Department of Surgery, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital, Boston, MA, United States
| | - Yunzhou Dong
- Department of Surgery, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital, Boston, MA, United States
| | - Siu-Lung Chan
- Department of Surgery, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital, Boston, MA, United States
| | - Douglas Cowan
- Department of Surgery, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital, Boston, MA, United States
| | - Jian Xu
- Department of Medicine, Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma, OK, United States
| | - Diane R. Bielenberg
- Department of Surgery, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital, Boston, MA, United States
| | - Changcheng Zhou
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, United States
| | - Hong Chen
- Department of Surgery, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital, Boston, MA, United States
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Tian X, Bunda P, Ishibe S. Podocyte Endocytosis in Regulating the Glomerular Filtration Barrier. Front Med (Lausanne) 2022; 9:801837. [PMID: 35223901 PMCID: PMC8866310 DOI: 10.3389/fmed.2022.801837] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 01/06/2022] [Indexed: 12/26/2022] Open
Abstract
Endocytosis is a mechanism that internalizes and recycles plasma membrane components and transmembrane receptors via vesicle formation, which is mediated by clathrin-dependent and clathrin-independent signaling pathways. Podocytes are specialized, terminally differentiated epithelial cells in the kidney, located on the outermost layer of the glomerulus. These cells play an important role in maintaining the integrity of the glomerular filtration barrier in conjunction with the adjacent basement membrane and endothelial cell layers within the glomerulus. An intact podocyte endocytic machinery appears to be necessary for maintaining podocyte function. De novo pathologic human genetic mutations and loss-of-function studies of critical podocyte endocytosis genes in genetically engineered mouse models suggest that this pathway contributes to the pathophysiology of development and progression of proteinuria in chronic kidney disease. Here, we review the mechanism of cellular endocytosis and its regulation in podocyte injury in the context of glomerular diseases. A thorough understanding of podocyte endocytosis may shed novel insights into its biological function in maintaining a functioning filter and offer potential targeted therapeutic strategies for proteinuric glomerular diseases.
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Affiliation(s)
| | | | - Shuta Ishibe
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT, United States
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Xiong Y, Zhu W, Xu Q, Ruze R, Yan Z, Li J, Hu S, Zhong M, Cheng Y, Zhang G. Sleeve Gastrectomy Attenuates Diabetic Nephropathy by Upregulating Nephrin Expressions in Diabetic Obese Rats. Obes Surg 2021; 30:2893-2904. [PMID: 32399849 DOI: 10.1007/s11695-020-04611-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
PURPOSE Diabetic nephropathy (DN) is the leading cause of end-stage renal disease, and sleeve gastrectomy (SG) is considered to be an effective strategy to improve pre-existing DN. However, the mechanism remains unknown. MATERIALS AND METHODS Animal model of DN was induced by high-fat diet (HFD) and streptozotocin (STZ). SG or sham surgery was performed and rats were sacrificed at 4, 8, and 12 weeks after surgery. The basic parameters (blood glucose, body weight, kidney weight), indicators of renal function including serum creatinine (Scr), blood urea nitrogen (BUN), urine microalbumin, urine creatinine (Ucr), microalbumin creatinine ratio (UACR), ultrastructural changes of glomerulus, and the expression of nephrin gene and protein in glomerular podocytes were compared among groups. RESULTS Blood glucose and body weight of SG rats were significantly lower than those of the sham-operated rats, and renal function of SG groups were also significantly improved within the postoperative period of 12 weeks. The results of periodic acid-Schiff staining (PAS) and transmission electron microscopy (TEM) showed that glomerular hypertrophy and accumulation of extracellular matrix proteins were significantly alleviated after SG, and the thickness of basement membrane and the fusion or effacement of foot processes were also significantly improved. The mRNA and protein expression of nephrin in SG groups was significantly higher than that in the sham group. CONCLUSION These results suggest that SG attenuates DN by upregulating the expression of nephrin and improving the ultrastructure of glomerular filtration membrane. This study indicates that SG can be used as an available therapeutic intervention for DN.
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Affiliation(s)
- Yacheng Xiong
- Department of General Surgery, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, 250014, Shandong Province, People's Republic of China
| | - Wei Zhu
- Shandong Medical College, Jucai 6# Road, Linyi, 276000, Shandong Province, People's Republic of China
| | - Qian Xu
- Department of General Surgery, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, 250014, Shandong Province, People's Republic of China
| | - Rexiati Ruze
- Department of General Surgery, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, 250014, Shandong Province, People's Republic of China
| | - Zhibo Yan
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, 250012, Shandong Province, People's Republic of China
| | - Jianwen Li
- Department of General Surgery, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200025, People's Republic of China
| | - Sanyuan Hu
- Department of General Surgery, The First Affiliated Hospital of Shandong First Medical University, 16766#, Jingshi Road, Jinan, 250014, Shandong Province, China
| | - Mingwei Zhong
- Department of General Surgery, The First Affiliated Hospital of Shandong First Medical University, 16766#, Jingshi Road, Jinan, 250014, Shandong Province, China
| | - Yugang Cheng
- Department of General Surgery, The First Affiliated Hospital of Shandong First Medical University, 16766#, Jingshi Road, Jinan, 250014, Shandong Province, China
| | - Guangyong Zhang
- Department of General Surgery, The First Affiliated Hospital of Shandong First Medical University, 16766#, Jingshi Road, Jinan, 250014, Shandong Province, China.
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10
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Kondapi K, Kumar NL, Moorthy S, Silambanan S. A Study of Association of Urinary Nephrin with Albuminuria in Patients with Diabetic Nephropathy. Indian J Nephrol 2021; 31:142-148. [PMID: 34267436 PMCID: PMC8240926 DOI: 10.4103/ijn.ijn_305_19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 12/13/2019] [Accepted: 12/23/2019] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND AND AIMS Diabetes mellitus and its complications are associated with high mortality and morbidity. Early detection is mandatory to improve quality of life years in patients with diabetic nephropathy. Hyperglycaemia disrupts podocytes, both structurally and functionally, leading to excretion of nephrin which is present in the glomerular filtration barrier. This study was undertaken to find out whether urinary nephrin is a better indicator of podocyte injury than albuminuria in patients with diabetic nephropathy. METHODS The study included 125 type 2 diabetes mellitus patients as cases categorized into three groups, depending upon albumin excretion. Age and sex matched 45 individuals without diabetes mellitus were chosen as the control group. The study protocol was approved by Institutional Ethics committee. Microalbumin was estimated by immunoturbidometry and urinary nephrin by ELISA. ANOVA and Tukey post-hoc tests were done to compare the data between the groups. Correlation studies were done. Odds ratio for nephrin was calculated. P value less than 0.05 was considered statistically significant. The statistical analyses were performed with SPSS software version 13.0. RESULTS The urinary nephrin was found to be proportionately increased from normoalbuminuria to macroalbuminuria and it was statistically significant, with sensitivity of 92.5% and specificity of 76.7%, the cut-off value of urinary nephrin was 97.5ng/mL. CONCLUSION Albuminuria has been used as an independent predictor of diabetic nephropathy. The statistical significant difference between the groups inferred that urinary nephrin excretion increased even in the stage of normoalbuminuria. Nephrin expression and its phosphorylation get altered by hyperglycaemia, contributing to renal damage. Nephrin was found to be a sensitive marker of early kidney dysfunction in diabetic patients.
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Affiliation(s)
- Kishore Kondapi
- Department of Biochemistry, SRMC & RI, Sri Ramachandra Institute of Higher Education Research (Deemed to be University), Porur, Chennai 600116, Chennai, Tamil Nadu, India
| | - N. Lakshmana Kumar
- Department of Biochemistry, GSL Medical College, Rajahmundry, Andhra Pradesh, India
| | - Swathi Moorthy
- Department of General Medicine, SRMC & RI, Sri Ramachandra Institute of Higher Education Research (Deemed to be University), Porur, Chennai 600116, Chennai, Tamil Nadu, India
| | - Santhi Silambanan
- Department of Biochemistry, SRMC & RI, Sri Ramachandra Institute of Higher Education Research (Deemed to be University), Porur, Chennai 600116, Chennai, Tamil Nadu, India
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11
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Sun H, Perez-Gill C, Schlöndorff JS, Subramanian B, Pollak MR. Dysregulated Dynein-Mediated Trafficking of Nephrin Causes INF2-related Podocytopathy. J Am Soc Nephrol 2021; 32:307-322. [PMID: 33443052 PMCID: PMC8054882 DOI: 10.1681/asn.2020081109] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 10/20/2020] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND FSGS caused by mutations in INF2 is characterized by a podocytopathy with mistrafficked nephrin, an essential component of the slit diaphragm. Because INF2 is a formin-type actin nucleator, research has focused on its actin-regulating function, providing an important but incomplete insight into how these mutations lead to podocytopathy. A yeast two-hybridization screen identified the interaction between INF2 and the dynein transport complex, suggesting a newly recognized role of INF2 in regulating dynein-mediated vesicular trafficking in podocytes. METHODS Live cell and quantitative imaging, fluorescent and surface biotinylation-based trafficking assays in cultured podocytes, and a new puromycin aminoglycoside nephropathy model of INF2 transgenic mice were used to demonstrate altered dynein-mediated trafficking of nephrin in INF2 associated podocytopathy. RESULTS Pathogenic INF2 mutations disrupt an interaction of INF2 with dynein light chain 1, a key dynein component. The best-studied mutation, R218Q, diverts dynein-mediated postendocytic sorting of nephrin from recycling endosomes to lysosomes for degradation. Antagonizing dynein-mediated transport can rescue this effect. Augmented dynein-mediated trafficking and degradation of nephrin underlies puromycin aminoglycoside-induced podocytopathy and FSGS in vivo. CONCLUSIONS INF2 mutations enhance dynein-mediated trafficking of nephrin to proteolytic pathways, diminishing its recycling required for maintaining slit diaphragm integrity. The recognition that dysregulated dynein-mediated transport of nephrin in R218Q knockin podocytes opens an avenue for developing targeted therapy for INF2-mediated FSGS.
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Affiliation(s)
- Hua Sun
- Division of Nephrology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
- Renal Division, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
- Stead Family Department of Pediatrics, University of Iowa, Iowa City, Iowa
| | - Chandra Perez-Gill
- Division of Nephrology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Johannes S Schlöndorff
- Division of Nephrology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Balajikarthick Subramanian
- Division of Nephrology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Martin R. Pollak
- Division of Nephrology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
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12
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Nakamichi R, Hayashi K, Itoh H. Effects of High Glucose and Lipotoxicity on Diabetic Podocytes. Nutrients 2021; 13:nu13010241. [PMID: 33467659 PMCID: PMC7830342 DOI: 10.3390/nu13010241] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/11/2020] [Accepted: 01/11/2021] [Indexed: 01/19/2023] Open
Abstract
Glomerular podocytes are highly differentiated cells that cover glomerular capillaries from the outside and have a characteristic morphology with numerous foot processes. The formation of slit membranes between the foot processes serves as a final filtration barrier for urine filtration from the blood. Podocyte damage causes disruption of the slit membrane, subsequent proteinuria and finally glomerulosclerosis, which is a common pathway in various types of chronic kidney disease (CKD). In recent years, there has been an increase in diabetes, due to rapid lifestyle changes, which is the main cause of CKD. Therefore, understanding the effect of diabetic status on podocytes is of great importance to establish a strategy for preventing CKD progression. In this review, we summarize altered glucose and lipid metabolism in diabetic podocytes and also discuss the reversibility of the changes in podocyte phenotype.
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Affiliation(s)
| | - Kaori Hayashi
- Correspondence: ; Tel.: +81-3-5363-3796; Fax: +81-3-3359-2745
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13
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Lehtonen S. Metformin Protects against Podocyte Injury in Diabetic Kidney Disease. Pharmaceuticals (Basel) 2020; 13:ph13120452. [PMID: 33321755 PMCID: PMC7764076 DOI: 10.3390/ph13120452] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/06/2020] [Accepted: 12/08/2020] [Indexed: 02/07/2023] Open
Abstract
Metformin is the most commonly prescribed drug for treating type 2 diabetes mellitus (T2D). Its mechanisms of action have been under extensive investigation, revealing that it has multiple cellular targets, either direct or indirect ones, via which it regulates numerous cellular pathways. Diabetic kidney disease (DKD), the serious complication of T2D, develops in up to 50% of the individuals with T2D. Various mechanisms contribute to the development of DKD, including hyperglycaemia, dyslipidemia, oxidative stress, chronic low-grade inflammation, altered autophagic activity and insulin resistance, among others. Metformin has been shown to affect these pathways, and thus, it could slow down or prevent the progression of DKD. Despite several animal studies demonstrating the renoprotective effects of metformin, there is no concrete evidence in clinical settings. This review summarizes the renoprotective effects of metformin in experimental settings. Special emphasis is on the effects of metformin on podocytes, the glomerular epithelial cells that are central in maintaining the glomerular ultrafiltration function.
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Affiliation(s)
- Sanna Lehtonen
- Research Program for Clinical and Molecular Metabolism and Department of Pathology, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
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14
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Nguyen LP, Tran SC, Suetsugu S, Lim YS, Hwang SB. PACSIN2 Interacts with Nonstructural Protein 5A and Regulates Hepatitis C Virus Assembly. J Virol 2020; 94:e01531-19. [PMID: 31801866 PMCID: PMC7022371 DOI: 10.1128/jvi.01531-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 11/26/2019] [Indexed: 12/12/2022] Open
Abstract
Hepatitis C virus (HCV) is a major etiologic agent of chronic liver diseases. HCV is highly dependent on cellular machinery for viral propagation. Using protein microarray analysis, we previously identified 90 cellular proteins as nonstructural 5A (NS5A) interacting partners. Of these, protein kinase C and casein kinase substrate in neurons protein 2 (PACSIN2) was selected for further study. PACSIN2 belongs to the PACSIN family, which is involved in the formation of caveolae. Protein interaction between NS5A and PACSIN2 was confirmed by pulldown assay and further verified by both coimmunoprecipitation and immunofluorescence assays. We showed that PACSIN2 interacted with domain I of NS5A and the Fer-CIP4 homology (FCH)-Bin/amphiphysin/Rvs (F-BAR) region of PACSIN2. Interestingly, NS5A specifically attenuated protein kinase C alpha (PKCα)-mediated phosphorylation of PACSIN2 at serine 313 by interrupting PACSIN2 and PKCα interaction. In fact, mutation of the serine 313 to alanine (S313A) of PACSIN2 increased protein interaction with NS5A. Silencing of PACSIN2 decreased both viral RNA and protein expression levels of HCV. Ectopic expression of the small interfering RNA (siRNA)-resistant PACSIN2 recovered the viral infectivity, suggesting that PACSIN2 was specifically required for HCV propagation. PACSIN2 was involved in viral assembly without affecting other steps of the HCV life cycle. Indeed, overexpression of PACSIN2 promoted NS5A and core protein (core) interaction. We further showed that inhibition of PKCα increased NS5A and core interaction, suggesting that phosphorylation of PACSIN2 might influence HCV assembly. Moreover, PACSIN2 was required for lipid droplet formation via modulating extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation. Taken together, these data indicate that HCV modulates PACSIN2 via NS5A to promote virion assembly.IMPORTANCE PACSIN2 is a lipid-binding protein that triggers the tubulation of the phosphatidic acid-containing membranes. The functional involvement of PACSIN2 in the virus life cycle has not yet been demonstrated. We showed that phosphorylation of PACSIN2 displayed a negative effect on NS5A and core interaction. The most significant finding is that NS5A prevents PKCα from binding to PACSIN2. Therefore, the phosphorylation level of PACSIN2 is decreased in HCV-infected cells. We showed that HCV NS5A interrupted PKCα-mediated PACSIN2 phosphorylation at serine 313, thereby promoting NS5A-PACSIN2 interaction. We further demonstrated that PACSIN2 modulated lipid droplet formation through ERK1/2 phosphorylation. These data provide evidence that PACSIN2 is a proviral cellular factor required for viral propagation.
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Affiliation(s)
- Lap P Nguyen
- Laboratory of RNA Viral Diseases, Korea Zoonosis Research Institute, Chonbuk National University, Iksan, South Korea
- National Research Laboratory of Hepatitis C Virus and Ilsong Institute of Life Science, Hallym University, Anyang, South Korea
| | - Si C Tran
- National Research Laboratory of Hepatitis C Virus and Ilsong Institute of Life Science, Hallym University, Anyang, South Korea
| | - Shiro Suetsugu
- Laboratory of Molecular Medicine and Cell Biology, Graduate School of Biosciences, Nara Institute of Science and Technology, Ikoma, Japan
| | - Yun-Sook Lim
- Laboratory of RNA Viral Diseases, Korea Zoonosis Research Institute, Chonbuk National University, Iksan, South Korea
- National Research Laboratory of Hepatitis C Virus and Ilsong Institute of Life Science, Hallym University, Anyang, South Korea
| | - Soon B Hwang
- Laboratory of RNA Viral Diseases, Korea Zoonosis Research Institute, Chonbuk National University, Iksan, South Korea
- National Research Laboratory of Hepatitis C Virus and Ilsong Institute of Life Science, Hallym University, Anyang, South Korea
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15
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Rahman MH, Peng S, Hu X, Chen C, Rahman MR, Uddin S, Quinn JM, Moni MA. A Network-Based Bioinformatics Approach to Identify Molecular Biomarkers for Type 2 Diabetes that Are Linked to the Progression of Neurological Diseases. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17031035. [PMID: 32041280 PMCID: PMC7037290 DOI: 10.3390/ijerph17031035] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/02/2020] [Accepted: 02/02/2020] [Indexed: 12/21/2022]
Abstract
Neurological diseases (NDs) are progressive disorders, the progression of which can be significantly affected by a range of common diseases that present as comorbidities. Clinical studies, including epidemiological and neuropathological analyses, indicate that patients with type 2 diabetes (T2D) have worse progression of NDs, suggesting pathogenic links between NDs and T2D. However, finding causal or predisposing factors that link T2D and NDs remains challenging. To address these problems, we developed a high-throughput network-based quantitative pipeline using agnostic approaches to identify genes expressed abnormally in both T2D and NDs, to identify some of the shared molecular pathways that may underpin T2D and ND interaction. We employed gene expression transcriptomic datasets from control and disease-affected individuals and identified differentially expressed genes (DEGs) in tissues of patients with T2D and ND when compared to unaffected control individuals. One hundred and ninety seven DEGs (99 up-regulated and 98 down-regulated in affected individuals) that were common to both the T2D and the ND datasets were identified. Functional annotation of these identified DEGs revealed the involvement of significant cell signaling associated molecular pathways. The overlapping DEGs (i.e., seen in both T2D and ND datasets) were then used to extract the most significant GO terms. We performed validation of these results with gold benchmark databases and literature searching, which identified which genes and pathways had been previously linked to NDs or T2D and which are novel. Hub proteins in the pathways were identified (including DNM2, DNM1, MYH14, PACSIN2, TFRC, PDE4D, ENTPD1, PLK4, CDC20B, and CDC14A) using protein-protein interaction analysis which have not previously been described as playing a role in these diseases. To reveal the transcriptional and post-transcriptional regulators of the DEGs we used transcription factor (TF) interactions analysis and DEG-microRNAs (miRNAs) interaction analysis, respectively. We thus identified the following TFs as important in driving expression of our T2D/ND common genes: FOXC1, GATA2, FOXL1, YY1, E2F1, NFIC, NFYA, USF2, HINFP, MEF2A, SRF, NFKB1, USF2, HINFP, MEF2A, SRF, NFKB1, PDE4D, CREB1, SP1, HOXA5, SREBF1, TFAP2A, STAT3, POU2F2, TP53, PPARG, and JUN. MicroRNAs that affect expression of these genes include mir-335-5p, mir-16-5p, mir-93-5p, mir-17-5p, mir-124-3p. Thus, our transcriptomic data analysis identifies novel potential links between NDs and T2D pathologies that may underlie comorbidity interactions, links that may include potential targets for therapeutic intervention. In sum, our neighborhood-based benchmarking and multilayer network topology methods identified novel putative biomarkers that indicate how type 2 diabetes (T2D) and these neurological diseases interact and pathways that, in the future, may be targeted for treatment.
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Affiliation(s)
- Md Habibur Rahman
- Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China; (M.H.R.); (S.P.); (X.H.); (C.C.)
- University of Chinese Academy of Sciences, Beijing 100190, China
- Department of Computer Science and Engineering, Islamic University, Kushtia 7003, Bangladesh
| | - Silong Peng
- Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China; (M.H.R.); (S.P.); (X.H.); (C.C.)
- University of Chinese Academy of Sciences, Beijing 100190, China
| | - Xiyuan Hu
- Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China; (M.H.R.); (S.P.); (X.H.); (C.C.)
- University of Chinese Academy of Sciences, Beijing 100190, China
| | - Chen Chen
- Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China; (M.H.R.); (S.P.); (X.H.); (C.C.)
- University of Chinese Academy of Sciences, Beijing 100190, China
| | - Md Rezanur Rahman
- Department of Biochemistry and Biotechnology, Khwaja Yunus Ali University, Enayetpur, Sirajgonj 6751, Bangladesh;
| | - Shahadat Uddin
- Complex Systems Research Group & Project Management Program, Faculty of Engineering, The University of Sydney, Sydney, NSW 2006, Australia;
| | - Julian M.W. Quinn
- Bone Biology Division, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia;
| | - Mohammad Ali Moni
- Bone Biology Division, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia;
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
- Correspondence:
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16
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Criscitiello MF, Kraev I, Lange S. Deiminated proteins in extracellular vesicles and serum of llama (Lama glama)-Novel insights into camelid immunity. Mol Immunol 2020; 117:37-53. [PMID: 31733447 PMCID: PMC7112542 DOI: 10.1016/j.molimm.2019.10.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 10/05/2019] [Accepted: 10/23/2019] [Indexed: 02/07/2023]
Abstract
Peptidylarginine deiminases (PADs) are phylogenetically conserved calcium-dependent enzymes which post-translationally convert arginine into citrulline in target proteins in an irreversible manner, causing functional and structural changes in target proteins. Protein deimination causes generation of neo-epitopes, affects gene regulation and also allows for protein moonlighting. Furthermore, PADs have been found to be a phylogenetically conserved regulator for extracellular vesicle (EVs) release. EVs are found in most body fluids and participate in cellular communication via transfer of cargo proteins and genetic material. In this study, post-translationally deiminated proteins in serum and serum-EVs are described for the first time in camelids, using the llama (Lama glama L. 1758) as a model animal. We report a poly-dispersed population of llama serum EVs, positive for phylogenetically conserved EV-specific markers and characterised by TEM. In serum, 103 deiminated proteins were overall identified, including key immune and metabolic mediators including complement components, immunoglobulin-based nanobodies, adiponectin and heat shock proteins. In serum, 60 deiminated proteins were identified that were not in EVs, and 25 deiminated proteins were found to be unique to EVs, with 43 shared deiminated protein hits between both serum and EVs. Deiminated histone H3, a marker of neutrophil extracellular trap formation, was also detected in llama serum. PAD homologues were identified in llama serum by Western blotting, via cross reaction with human PAD antibodies, and detected at an expected 70 kDa size. This is the first report of deiminated proteins in serum and EVs of a camelid species, highlighting a hitherto unrecognized post-translational modification in key immune and metabolic proteins in camelids, which may be translatable to and inform a range of human metabolic and inflammatory pathologies.
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Affiliation(s)
- Michael F Criscitiello
- Comparative Immunogenetics Laboratory, Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843, USA; Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M Health Science Center, Texas A&M University, College Station, TX, 77843, USA.
| | - Igor Kraev
- Electron Microscopy Suite, Faculty of Science, Technology, Engineering and Mathematics, Open University, Milton Keynes, MK7 6AA, UK.
| | - Sigrun Lange
- Tissue Architecture and Regeneration Research Group, School of Life Sciences, University of Westminster, London W1W 6UW, UK.
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17
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Lehtonen S. SHIPping out diabetes-Metformin, an old friend among new SHIP2 inhibitors. Acta Physiol (Oxf) 2020; 228:e13349. [PMID: 31342643 PMCID: PMC6916339 DOI: 10.1111/apha.13349] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 07/15/2019] [Accepted: 07/19/2019] [Indexed: 02/06/2023]
Abstract
SHIP2 (Src homology 2 domain‐containing inositol 5′‐phosphatase 2) belongs to the family of 5′‐phosphatases. It regulates the phosphoinositide 3‐kinase (PI3K)‐mediated insulin signalling cascade by dephosphorylating the 5′‐position of PtdIns(3,4,5)P3 to generate PtdIns(3,4)P2, suppressing the activity of the pathway. SHIP2 mouse models and genetic studies in human propose that increased expression or activity of SHIP2 contributes to the pathogenesis of the metabolic syndrome, hypertension and type 2 diabetes. This has raised great interest to identify SHIP2 inhibitors that could be used to design new treatments for metabolic diseases. This review summarizes the central mechanisms associated with the development of diabetic kidney disease, including the role of insulin resistance, and then moves on to describe the function of SHIP2 as a regulator of metabolism in mouse models. Finally, the identification of SHIP2 inhibitors and their effects on metabolic processes in vitro and in vivo are outlined. One of the newly identified SHIP2 inhibitors is metformin, the first‐line medication prescribed to patients with type 2 diabetes, further boosting the attraction of SHIP2 as a treatment target to ameliorate metabolic disorders.
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Affiliation(s)
- Sanna Lehtonen
- Department of Pathology and Research Program for Clinical and Molecular Metabolism, Faculty of Medicine University of Helsinki Helsinki Finland
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18
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Yu J, Zong GN, Wu H, Zhang KQ. Podoplanin mediates the renoprotective effect of berberine on diabetic kidney disease in mice. Acta Pharmacol Sin 2019; 40:1544-1554. [PMID: 31270434 PMCID: PMC7470856 DOI: 10.1038/s41401-019-0263-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Accepted: 05/22/2019] [Indexed: 11/29/2022] Open
Abstract
Hyperglycemia-caused podocyte injury plays a crucial role in the progress of diabetic kidney disease. Podoplanin, one of the podocyte-associated molecules, is closely related to the integrity of the glomerular filtration barrier. A number of studies demonstrate that berberine could ameliorate renal dysfunction in diabetic mice with nephropathy, but the molecular mechanisms have not been fully elucidated. In this study, we explored the relationship between the renoprotective effect of berberine and podoplanin expression in streptozotocin (STZ)-induced diabetic mice as well as mouse podocytes (MPC5 cells) cultured in high glucose (HG, 30 mM) medium. We found that the expression levels of podoplanin were significantly decreased both in the renal glomerulus of STZ-induced diabetic mice and HG-cultured MPC5 cells. We also demonstrated that NF-κB signaling pathway was activated in MPC5 cells under HG condition, which downregulated the expression level of podoplanin, thus leading to increased podocyte apoptosis. Administration of berberine (100, 200 mg/kg every day, ig, for 8 weeks) significantly improved hyperglycemia and the renal function of STZ-induced diabetic mice and restored the expression level of podoplanin in renal glomerulus. In high glucose-cultured MPC5 cells, treatment with berberine (30–120 μM) dose-dependently decreased the apoptosis rate, increased the expression of podoplanin, and inhibited the activation of NF-κB signaling pathway. When podoplanin expression was silenced with shRNA, berberine treatment still inhibited the NF-κB signaling pathway, but its antiapoptotic effect on podocytes almost disappeared. Our results suggest that berberine inhibits the activation of NF-κB signaling pathway, thus increasing the podoplanin expression to exert renoprotective effects.
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19
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IQGAP1 mediates podocyte injury in diabetic kidney disease by regulating nephrin endocytosis. Cell Signal 2019; 59:13-23. [DOI: 10.1016/j.cellsig.2019.03.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 03/07/2019] [Accepted: 03/08/2019] [Indexed: 01/02/2023]
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20
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Torban E, Braun F, Wanner N, Takano T, Goodyer PR, Lennon R, Ronco P, Cybulsky AV, Huber TB. From podocyte biology to novel cures for glomerular disease. Kidney Int 2019; 96:850-861. [PMID: 31420194 DOI: 10.1016/j.kint.2019.05.015] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 04/23/2019] [Accepted: 05/13/2019] [Indexed: 01/20/2023]
Abstract
The podocyte is a key component of the glomerular filtration barrier. Podocyte dysfunction is central to the underlying pathophysiology of many common glomerular diseases, including diabetic nephropathy, glomerulonephritis and genetic forms of nephrotic syndrome. Collectively, these conditions affect millions of people worldwide, and account for the majority of kidney diseases requiring dialysis and transplantation. The 12th International Podocyte Conference was held in Montreal, Canada from May 30 to June 2, 2018. The primary aim of this conference was to bring together nephrologists, clinician scientists, basic scientists and their trainees from all over the world to present their research and to establish networks with the common goal of developing new therapies for glomerular diseases based on the latest advances in podocyte biology. This review briefly highlights recent advances made in understanding podocyte structure and metabolism, experimental systems in which to study podocytes and glomerular disease, disease mediators, genetic and immune origins of glomerulopathies, and the development of novel therapeutic agents to protect podocyte and glomerular injury.
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Affiliation(s)
- Elena Torban
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada.
| | - Fabian Braun
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nicola Wanner
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tomoko Takano
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
| | - Paul R Goodyer
- Department of Pediatrics, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
| | - Rachel Lennon
- Wellcome Centre for Cell-Matrix Research, University of Manchester, Manchester, UK
| | - Pierre Ronco
- Sorbonne University, INSERM UMR_S 1155, and Nephrology and Dialysis Department, Hôpital Tenon, Paris France
| | - Andrey V Cybulsky
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
| | - Tobias B Huber
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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21
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Bovo S, Mazzoni G, Bertolini F, Schiavo G, Galimberti G, Gallo M, Dall'Olio S, Fontanesi L. Genome-wide association studies for 30 haematological and blood clinical-biochemical traits in Large White pigs reveal genomic regions affecting intermediate phenotypes. Sci Rep 2019; 9:7003. [PMID: 31065004 PMCID: PMC6504931 DOI: 10.1038/s41598-019-43297-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 04/16/2019] [Indexed: 12/20/2022] Open
Abstract
Haematological and clinical-biochemical parameters are considered indicators of the physiological/health status of animals and might serve as intermediate phenotypes to link physiological aspects to production and disease resistance traits. The dissection of the genetic variability affecting these phenotypes might be useful to describe the resilience of the animals and to support the usefulness of the pig as animal model. Here, we analysed 15 haematological and 15 clinical-biochemical traits in 843 Italian Large White pigs, via three genome-wide association scan approaches (single-trait, multi-trait and Bayesian). We identified 52 quantitative trait loci (QTLs) associated with 29 out of 30 analysed blood parameters, with the most significant QTL identified on porcine chromosome 14 for basophil count. Some QTL regions harbour genes that may be the obvious candidates: QTLs for cholesterol parameters identified genes (ADCY8, APOB, ATG5, CDKAL1, PCSK5, PRL and SOX6) that are directly involved in cholesterol metabolism; other QTLs highlighted genes encoding the enzymes being measured [ALT (known also as GPT) and AST (known also as GOT)]. Moreover, the multivariate approach strengthened the association results for several candidate genes. The obtained results can contribute to define new measurable phenotypes that could be applied in breeding programs as proxies for more complex traits.
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Affiliation(s)
- Samuele Bovo
- Department of Agricultural and Food Sciences, Division of Animal Sciences, University of Bologna, Viale G. Fanin 46, 40127, Bologna, Italy
| | - Gianluca Mazzoni
- Department of Health Technology, Technical University of Denmark (DTU), Lyngby, 2800, Denmark
| | - Francesca Bertolini
- National Institute of Aquatic Resources, Technical University of Denmark (DTU), Lyngby, 2800, Denmark
| | - Giuseppina Schiavo
- Department of Agricultural and Food Sciences, Division of Animal Sciences, University of Bologna, Viale G. Fanin 46, 40127, Bologna, Italy
| | - Giuliano Galimberti
- Department of Statistical Sciences "Paolo Fortunati", University of Bologna, Via delle Belle Arti 41, 40126, Bologna, Italy
| | - Maurizio Gallo
- Associazione Nazionale Allevatori Suini (ANAS), Via Nizza 53, 00198, Roma, Italy
| | - Stefania Dall'Olio
- Department of Agricultural and Food Sciences, Division of Animal Sciences, University of Bologna, Viale G. Fanin 46, 40127, Bologna, Italy
| | - Luca Fontanesi
- Department of Agricultural and Food Sciences, Division of Animal Sciences, University of Bologna, Viale G. Fanin 46, 40127, Bologna, Italy.
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22
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Luo J, Chen J, Sun Y, Zhou H, Xu K, Huang F, Huang P. Quantitative contrast-enhanced ultrasound of renal perfusion: a technology for the assessment of early diabetic nephropathy in cynomolgus macaques with type 2 diabetes mellitus. Abdom Radiol (NY) 2019; 44:1850-1857. [PMID: 30694370 DOI: 10.1007/s00261-019-01908-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
PURPOSE The aim of this study was to investigate the effectiveness of contrast-enhanced ultrasound (CEUS) in predicting early nephropathy in cynomolgus macaques with spontaneous type 2 diabetes mellitus (T2DM). METHODS Six cynomolgus macaques with spontaneous T2DM and six normal cynomolgus macaques (Group 1) were included in this study. The time-intensity curve was used to obtain parameters such as peak values, red blood volume (RBV), red blood flow (RBF), time to peak (TTP), and mean transit time (MTT). Biopsy renal tissue samples were assessed histopathologically. Six cynomolgus macaques with spontaneous T2DM were subgrouped into T2DM without nephropathy group (Group 2) and T2DM with nephropathy group (Group 3) based on histopathological findings. RESULTS Peak value had the largest area under the curve comparing with RBF, RBV, TTP, MTT. The sensitivity and specificity of peak value with cut-off value of 38.65 dB for the diagnosis of DN were 98.3% and 83%, respectively. Peak value, RBV, and RBF in Group 3 was significantly decreased compared with Group 1 and Group 2 (P = 0.000, x2 = 23.99; P = 0.003, x2 = 9.14; P = 0.02, x2 = 5.14). CONCLUSIONS The perfusion parameter of peak value in CEUS might be useful in predicting early diabetic nephropathy in spontaneous T2DM cynomolgus macaques.
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Hinze C, Boucrot E. Endocytosis in proliferating, quiescent and terminally differentiated cells. J Cell Sci 2018; 131:131/23/jcs216804. [PMID: 30504135 DOI: 10.1242/jcs.216804] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Endocytosis mediates nutrient uptake, receptor internalization and the regulation of cell signaling. It is also hijacked by many bacteria, viruses and toxins to mediate their cellular entry. Several endocytic routes exist in parallel, fulfilling different functions. Most studies on endocytosis have used transformed cells in culture. However, as the majority of cells in an adult body have exited the cell cycle, our understanding is biased towards proliferating cells. Here, we review the evidence for the different pathways of endocytosis not only in dividing, but also in quiescent, senescent and terminally differentiated cells. During mitosis, residual endocytosis is dedicated to the internalization of caveolae and specific receptors. In non-dividing cells, clathrin-mediated endocytosis (CME) functions, but the activity of alternative processes, such as caveolae, macropinocytosis and clathrin-independent routes, vary widely depending on cell types and functions. Endocytosis supports the quiescent state by either upregulating cell cycle arrest pathways or downregulating mitogen-induced signaling, thereby inhibiting cell proliferation. Endocytosis in terminally differentiated cells, such as skeletal muscles, adipocytes, kidney podocytes and neurons, supports tissue-specific functions. Finally, uptake is downregulated in senescent cells, making them insensitive to proliferative stimuli by growth factors. Future studies should reveal the molecular basis for the differences in activities between the different cell states.
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Affiliation(s)
- Claudia Hinze
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, UK
| | - Emmanuel Boucrot
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, UK .,Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, London WC1E 7HX, UK
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Verma R, Venkatareddy M, Kalinowski A, Li T, Kukla J, Mollin A, Cara-Fuentes G, Patel SR, Garg P. Nephrin is necessary for podocyte recovery following injury in an adult mature glomerulus. PLoS One 2018; 13:e0198013. [PMID: 29924795 PMCID: PMC6010211 DOI: 10.1371/journal.pone.0198013] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 05/12/2018] [Indexed: 11/28/2022] Open
Abstract
Nephrin (Nphs1) is an adhesion protein that is expressed at the podocyte intercellular junction in the glomerulus. Nphs1 mutations in humans or deletion in animal genetic models results in a developmental failure of foot process formation. A number of studies have shown decrease in expression of nephrin in various proteinuric kidney diseases as well as in animal models of glomerular disease. Decrease in nephrin expression has been suggested to precede podocyte loss and linked to the progression of kidney disease. Whether the decrease in expression of nephrin is related to loss of podocytes or lead to podocyte detachment is unclear. To answer this central question we generated an inducible model of nephrin deletion (Nphs1Tam-Cre) in order to lower nephrin expression in healthy adult mice. Following tamoxifen-induction there was a 75% decrease in nephrin expression by 14 days. The Nphs1Tam-Cre mice had normal foot process ultrastructure and intact filtration barriers up to 4-6 weeks post-induction. Despite the loss of nephrin expression, the podocyte number and density remained unchanged during the initial period. Unexpectedly, nephrin expression, albeit at low levels persisted at the slit diaphragm up to 16-20 weeks post-tamoxifen induction. The mice became progressively proteinuric with glomerular hypertrophy and scarring reminiscent of focal and segmental glomerulosclerosis at 20 weeks. Four week-old Nphs1 knockout mice subjected to protamine sulfate model of podocyte injury demonstrated failure to recover from foot process effacement following heparin sulfate. Similarly, Nphs1 knockout mice failed to recover following nephrotoxic serum (NTS) with persistence of proteinuria and foot process effacement. Our results suggest that as in development, nephrin is necessary for maintenance of a healthy glomerular filter. In contrast to the developmental phenotype, lowering nephrin expression in a mature glomerulus resulted in a slowly progressive disease that histologically resembles FSGS a disease linked closely with podocyte depletion. Podocytes with low levels of nephrin expression are both susceptible and unable to recover following perturbation. Our results suggest that decreased nephrin expression independent of podocyte loss occurring as an early event in proteinuric kidney diseases might play a role in disease progression.
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Affiliation(s)
- Rakesh Verma
- Division of Nephrology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - Madhusudan Venkatareddy
- Division of Nephrology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - Anne Kalinowski
- Division of Nephrology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - Theodore Li
- Division of Nephrology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - Joanna Kukla
- Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | | | - Gabriel Cara-Fuentes
- Division of Pediatric Nephrology, Motts Children Hospital, Ann Arbor, Michigan, United States of America
| | - Sanjeevkumar R. Patel
- Division of Nephrology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
- Veterans Administration, VAMC, Ann Arbor, Michigan, United States of America
| | - Puneet Garg
- Division of Nephrology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
- Veterans Administration, VAMC, Ann Arbor, Michigan, United States of America
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Membrane re-modelling by BAR domain superfamily proteins via molecular and non-molecular factors. Biochem Soc Trans 2018. [PMID: 29540508 DOI: 10.1042/bst20170322] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Lipid membranes are structural components of cell surfaces and intracellular organelles. Alterations in lipid membrane shape are accompanied by numerous cellular functions, including endocytosis, intracellular transport, and cell migration. Proteins containing Bin-Amphiphysin-Rvs (BAR) domains (BAR proteins) are unique, because their structures correspond to the membrane curvature, that is, the shape of the lipid membrane. BAR proteins present at high concentration determine the shape of the membrane, because BAR domain oligomers function as scaffolds that mould the membrane. BAR proteins co-operate with various molecular and non-molecular factors. The molecular factors include cytoskeletal proteins such as the regulators of actin filaments and the membrane scission protein dynamin. Lipid composition, including saturated or unsaturated fatty acid tails of phospholipids, also affects the ability of BAR proteins to mould the membrane. Non-molecular factors include the external physical forces applied to the membrane, such as tension and friction. In this mini-review, we will discuss how the BAR proteins orchestrate membrane dynamics together with various molecular and non-molecular factors.
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Wasik AA, Lehtonen S. Glucose Transporters in Diabetic Kidney Disease-Friends or Foes? Front Endocrinol (Lausanne) 2018; 9:155. [PMID: 29686650 PMCID: PMC5900043 DOI: 10.3389/fendo.2018.00155] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 03/22/2018] [Indexed: 12/16/2022] Open
Abstract
Diabetic kidney disease (DKD) is a major microvascular complication of diabetes and a common cause of end-stage renal disease worldwide. DKD manifests as an increased urinary protein excretion (albuminuria). Multiple studies have shown that insulin resistance correlates with the development of albuminuria in non-diabetic and diabetic patients. There is also accumulating evidence that glomerular epithelial cells or podocytes are insulin sensitive and that insulin signaling in podocytes is essential for maintaining normal kidney function. At the cellular level, the mechanisms leading to the development of insulin resistance include mutations in the insulin receptor gene, impairments in the phosphoinositide 3-kinase (PI3K)/AKT signaling pathway, or perturbations in the trafficking of glucose transporters (GLUTs), which mediate the uptake of glucose into cells. Podocytes express several GLUTs, including GLUT1, GLUT2, GLUT3, GLUT4, and GLUT8. Of these, the most studied ones are GLUT1 and GLUT4, both shown to be insulin responsive in podocytes. In the basal state, GLUT4 is preferentially located in perinuclear and cytosolic vesicular structures and to a lesser extent at the plasma membrane. After insulin stimulation, GLUT4 is sorted into GLUT4-containing vesicles (GCVs) that translocate to the plasma membrane. GCV trafficking consists of several steps, including approaching of the GCVs to the plasma membrane, tethering, and docking, after which the lipid bilayers of the GCVs and the plasma membrane fuse, delivering GLUT4 to the cell surface for glucose uptake into the cell. Studies have revealed novel molecular regulators of the GLUT trafficking in podocytes and unraveled unexpected roles for GLUT1 and GLUT4 in the development of DKD, summarized in this review. These findings pave the way for better understanding of the mechanistic pathways associated with the development and progression of DKD and aid in the development of new treatments for this devastating disease.
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