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Raulien N, Friedrich K, Strobel S, Raps S, Hecker F, Pierer M, Schilling E, Lainka E, Kallinich T, Baumann S, Fritz-Wallace K, Rolle-Kampczyk U, von Bergen M, Aigner A, Ewe A, Schett G, Cross M, Rossol M, Wagner U. Glucose-oxygen deprivation constrains HMGCR function and Rac1 prenylation and activates the NLRP3 inflammasome in human monocytes. Sci Signal 2024; 17:eadd8913. [PMID: 39012939 DOI: 10.1126/scisignal.add8913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 11/03/2023] [Accepted: 06/26/2024] [Indexed: 07/18/2024]
Abstract
Hypoxia and low glucose abundance often occur simultaneously at sites of inflammation. In monocytes and macrophages, glucose-oxygen deprivation stimulates the assembly of the NLRP3 inflammasome to generate the proinflammatory cytokine IL-1β. We found that concomitant glucose deprivation and hypoxia activated the NLRP3 inflammasome by constraining the function of HMG-CoA reductase (HMGCR), the rate-limiting enzyme of the mevalonate kinase pathway. HMGCR is involved in the synthesis of geranylgeranyl pyrophosphate (GGPP), which is required for the prenylation and lipid membrane integration of proteins. Under glucose-oxygen deprivation, GGPP synthesis was decreased, leading to reduced prenylation of the small GTPase Rac1, increased binding of nonprenylated Rac1 to the scaffolding protein IQGAP1, and enhanced activation of the NLRP3 inflammasome. In response to restricted oxygen and glucose supply, patient monocytes with a compromised mevalonate pathway due to mevalonate kinase deficiency or Muckle-Wells syndrome released more IL-1β than did control monocytes. Thus, reduced GGPP synthesis due to inhibition of HMGCR under glucose-oxygen deprivation results in proinflammatory innate responses, which are normally kept in check by the prenylation of Rac1. We suggest that this mechanism is also active in inflammatory autoimmune conditions.
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Affiliation(s)
- Nora Raulien
- Division of Rheumatology, Department of Endocrinology, Nephrology, Rheumatology, Leipzig University, Leipzig, Germany
- Institute of Anatomy, University Leipzig, Leipzig, Germany
| | - Kathleen Friedrich
- Division of Rheumatology, Department of Endocrinology, Nephrology, Rheumatology, Leipzig University, Leipzig, Germany
| | - Sarah Strobel
- Division of Rheumatology, Department of Endocrinology, Nephrology, Rheumatology, Leipzig University, Leipzig, Germany
| | - Stefanie Raps
- Division of Rheumatology, Department of Endocrinology, Nephrology, Rheumatology, Leipzig University, Leipzig, Germany
| | - Friederike Hecker
- Division of Rheumatology, Department of Endocrinology, Nephrology, Rheumatology, Leipzig University, Leipzig, Germany
| | - Matthias Pierer
- Division of Rheumatology, Department of Endocrinology, Nephrology, Rheumatology, Leipzig University, Leipzig, Germany
| | - Erik Schilling
- Division of Rheumatology, Department of Endocrinology, Nephrology, Rheumatology, Leipzig University, Leipzig, Germany
| | - Elke Lainka
- Department of Pediatric Gastroenterology, Hepatology and Liver Transplantation, University Children's Hospital Essen, Essen, Germany
| | - Tilmann Kallinich
- Department of Pediatric Respiratory Medicine, Immunology and Critical Care Medicine, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Sven Baumann
- Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research GmbH, Leipzig, Germany
| | - Katarina Fritz-Wallace
- Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research GmbH, Leipzig, Germany
| | - Ulrike Rolle-Kampczyk
- Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research GmbH, Leipzig, Germany
| | - Martin von Bergen
- Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research GmbH, Leipzig, Germany
- Institute for Biochemistry, Faculty of Life Sciences, Leipzig University, Leipzig, Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Achim Aigner
- Rudolf-Boehm-Institute for Pharmacology and Toxicology, Clinical Pharmacology, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Alexander Ewe
- Rudolf-Boehm-Institute for Pharmacology and Toxicology, Clinical Pharmacology, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Georg Schett
- Department of Internal Medicine 3 - Rheumatology and Immunology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
- Deutsches Zentrum Immuntherapie, Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
| | - Michael Cross
- Leipzig Medical Center, Clinic for Hematology and Cell Therapy, University Clinic Leipzig, Leipzig, Germany
| | - Manuela Rossol
- Division of Rheumatology, Department of Endocrinology, Nephrology, Rheumatology, Leipzig University, Leipzig, Germany
- Molecular Immunology, Faculty of Health Sciences, Brandenburg Technische Universität Cottbus-Senftenberg, Senftenberg, Germany
| | - Ulf Wagner
- Division of Rheumatology, Department of Endocrinology, Nephrology, Rheumatology, Leipzig University, Leipzig, Germany
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Diao M, Tao Y, Liu Q, Huang L, Li H, Lin X. Rac1 promotes the lipopolysaccharide-induced inflammatory response and contraction-associated proteins (CAPs) expression in mouse uterine smooth muscle cells. Reprod Biol 2024; 24:100896. [PMID: 38833837 DOI: 10.1016/j.repbio.2024.100896] [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: 09/04/2023] [Revised: 05/11/2024] [Accepted: 05/15/2024] [Indexed: 06/06/2024]
Abstract
Activation of the maternal immune system leads to a downstream cascade of proinflammatory events that culminate in the activation of spontaneous uterine contractions, which is associated with preterm birth. Ras-related C3 botulinum toxin substrate 1 (Rac1) is a crucial protein related to cell contraction and inflammation. The main purpose of this study was to explore the role and function of Rac1's regulation of inflammation through in- vivo and in-vitro experiments. Rac1 inhibitor was used in animal model of preterm birth and cells isolated from the uterine tissues of pregnant mice on gestational day 16 were transfected with adenovirus to knockdown or overexpress Rac1 and treated with the Calcium-calmodulin-dependent protein kinase II (CaMKII) inhibitor KN93. The expression of Rac1, uterine contraction-associated proteins (CAPs) (COX-2 and Connexin43), and inflammatory cytokines, were assessed by Western blotting and RTPCR. LPS upregulated Rac1, COX-2 and Connexin43 expression in uterine smooth muscle cells (USMCs). The expression of inflammatory cytokines, COX-2, and Connexin43 was significantly decreased in shRac1-transfected cells compared with cells stimulated with LPS only. Rac1 overexpression led to an increase in the expression of inflammatory cytokines, COX-2, and Connexin43. Furthermore, after Rac1 overexpression, KN93 reduced the expression of uterine contraction-associated proteins and inflammatory cytokines. It is thought that the effect of Rac1 on inflammatory cytokine and contraction-associated protein expression in USMCs is mediated by CaMKII. Rac1 can modulate the expression of contraction-associated proteins and inflammatory cytokines through the CaMKII pathway. Rac1 could be an effective therapeutic target for improving the outcome of preterm birth.
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Affiliation(s)
- Min Diao
- Department of Anesthesiology, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China; Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, Sichuan, China
| | - Yunkai Tao
- Department of Anesthesiology, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China; Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, Sichuan, China
| | - Qian Liu
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China; Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, Sichuan, China
| | - Lu Huang
- Department of Anesthesiology, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China; Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, Sichuan, China
| | - Hao Li
- Department of Anesthesiology, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China; Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, Sichuan, China
| | - Xuemei Lin
- Department of Anesthesiology, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China; Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, Sichuan, China.
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3
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Zhu M, Liu Y, Chen C, Chen H, Ni W, Song Y, Lv B, Hua F, Cui G, Zhang Z. TLR4/Rac1/NLRP3 Pathway Mediates Amyloid-β-Induced Neuroinflammation in Alzheimer's Disease. J Alzheimers Dis 2024; 99:911-925. [PMID: 38728187 DOI: 10.3233/jad-240012] [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] [Indexed: 05/12/2024]
Abstract
Background Neuroinflammation plays a crucial part in the initial onset and progression of Alzheimer's disease (AD). NLRP3 inflammasome was demonstrated to get involved in amyloid-β (Aβ)-induced neuroinflammation. However, the mechanism of Aβ-triggered activation of NLRP3 inflammasome remains poorly understood. Objective Based on our previous data, the study aimed to identify the downstream signals that bridge the activation of TLR4 and NLRP3 inflammasome associated with Aβ. Methods BV-2 cells were transfected with TLR4siRNA or pretreated with a CLI-095 or NSC23766, followed by Aβ1-42 treatment. APP/PS1 mice were injected intraperitoneally with CLI-095 or NSC23766. NLRP3 inflammasome and microglia activation was detected with immunostaining and western blot. G-LISA and Rac1 pull-down activation test were performed to investigate the activation of Rac1. Real-time PCR and ELISA were used to detect the inflammatory cytokines. Aβ plaques were assessed by western blotting and immunofluorescence staining. Morris water maze test was conducted to determine the spatial memory in mice. Results Rac1 and NLRP3 inflammasome were activated by Aβ in both in vitro and in vivo experiments. Inhibition of TLR4 reduced the activity of Rac1 and NLRP3 inflammasome induced by Aβ1-42. Furthermore, inhibition of Rac1 blocked NLRP3 inflammasome activation mediated by TLR4. Blocking the pathway by CLI095 or NSC23766 suppressed Aβ1-42-triggered activation of microglia, reduced the expression of pro-inflammatory mediators and ameliorated the cognition deficits in APP/PS1 mice. Conclusions Our study demonstrated that TLR4/Rac1/NLRP3 pathway mediated Aβ-induced neuroinflammation, which unveiled a novel pathway and key contributors underlying the pathogenic mechanism of Aβ.
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Affiliation(s)
- Mengxin Zhu
- Institute of Neurological Diseases, Xuzhou Medical University, Xuzhou, China
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Yang Liu
- Institute of Neurological Diseases, Xuzhou Medical University, Xuzhou, China
- Department of Neurology, Xi'an People's hospital, Xi'an, China
| | - Chen Chen
- Department of Neurosurgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Hao Chen
- Institute of Neurological Diseases, Xuzhou Medical University, Xuzhou, China
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Wanyan Ni
- Institute of Neurological Diseases, Xuzhou Medical University, Xuzhou, China
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Yuanjian Song
- Department of Genetics, Xuzhou Medical University, Xuzhou, China
| | - Bingchen Lv
- Institute of Neurological Diseases, Xuzhou Medical University, Xuzhou, China
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Fang Hua
- Institute of Neurological Diseases, Xuzhou Medical University, Xuzhou, China
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Guiyun Cui
- Institute of Neurological Diseases, Xuzhou Medical University, Xuzhou, China
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Zuohui Zhang
- Institute of Neurological Diseases, Xuzhou Medical University, Xuzhou, China
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
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Sinha SK, Nicholas SB. Pathomechanisms of Diabetic Kidney Disease. J Clin Med 2023; 12:7349. [PMID: 38068400 PMCID: PMC10707303 DOI: 10.3390/jcm12237349] [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: 10/10/2023] [Revised: 11/15/2023] [Accepted: 11/22/2023] [Indexed: 03/15/2024] Open
Abstract
The worldwide occurrence of diabetic kidney disease (DKD) is swiftly rising, primarily attributed to the growing population of individuals affected by type 2 diabetes. This surge has been transformed into a substantial global concern, placing additional strain on healthcare systems already grappling with significant demands. The pathogenesis of DKD is intricate, originating with hyperglycemia, which triggers various mechanisms and pathways: metabolic, hemodynamic, inflammatory, and fibrotic which ultimately lead to renal damage. Within each pathway, several mediators contribute to the development of renal structural and functional changes. Some of these mediators, such as inflammatory cytokines, reactive oxygen species, and transforming growth factor β are shared among the different pathways, leading to significant overlap and interaction between them. While current treatment options for DKD have shown advancement over previous strategies, their effectiveness remains somewhat constrained as patients still experience residual risk of disease progression. Therefore, a comprehensive grasp of the molecular mechanisms underlying the onset and progression of DKD is imperative for the continued creation of novel and groundbreaking therapies for this condition. In this review, we discuss the current achievements in fundamental research, with a particular emphasis on individual factors and recent developments in DKD treatment.
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Affiliation(s)
- Satyesh K. Sinha
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA;
- College of Medicine, Charles R Drew University of Medicine and Science, Los Angeles, CA 90059, USA
| | - Susanne B. Nicholas
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA;
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Staruschenko A, Ma R, Palygin O, Dryer SE. Ion channels and channelopathies in glomeruli. Physiol Rev 2023; 103:787-854. [PMID: 36007181 PMCID: PMC9662803 DOI: 10.1152/physrev.00013.2022] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/15/2022] [Accepted: 08/21/2022] [Indexed: 11/22/2022] Open
Abstract
An essential step in renal function entails the formation of an ultrafiltrate that is delivered to the renal tubules for subsequent processing. This process, known as glomerular filtration, is controlled by intrinsic regulatory systems and by paracrine, neuronal, and endocrine signals that converge onto glomerular cells. In addition, the characteristics of glomerular fluid flow, such as the glomerular filtration rate and the glomerular filtration fraction, play an important role in determining blood flow to the rest of the kidney. Consequently, disease processes that initially affect glomeruli are the most likely to lead to end-stage kidney failure. The cells that comprise the glomerular filter, especially podocytes and mesangial cells, express many different types of ion channels that regulate intrinsic aspects of cell function and cellular responses to the local environment, such as changes in glomerular capillary pressure. Dysregulation of glomerular ion channels, such as changes in TRPC6, can lead to devastating glomerular diseases, and a number of channels, including TRPC6, TRPC5, and various ionotropic receptors, are promising targets for drug development. This review discusses glomerular structure and glomerular disease processes. It also describes the types of plasma membrane ion channels that have been identified in glomerular cells, the physiological and pathophysiological contexts in which they operate, and the pathways by which they are regulated and dysregulated. The contributions of these channels to glomerular disease processes, such as focal segmental glomerulosclerosis (FSGS) and diabetic nephropathy, as well as the development of drugs that target these channels are also discussed.
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Affiliation(s)
- Alexander Staruschenko
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida
- Hypertension and Kidney Research Center, University of South Florida, Tampa, Florida
- James A. Haley Veterans Hospital, Tampa, Florida
| | - Rong Ma
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Oleg Palygin
- Division of Nephrology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Stuart E Dryer
- Department of Biology and Biochemistry, University of Houston, Houston, Texas
- Department of Biomedical Sciences, Tilman J. Fertitta Family College of Medicine, University of Houston, Houston, Texas
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Yu Y, Dong H, Zhang Y, Sun J, Li B, Chen Y, Feng M, Yang X, Gao S, Jiang W. MicroRNA-223 downregulation promotes HBx-induced podocyte pyroptosis by targeting the NLRP3 inflammasome. Arch Virol 2022; 167:1841-1854. [PMID: 35731327 DOI: 10.1007/s00705-022-05499-3] [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] [Received: 12/27/2021] [Accepted: 04/21/2022] [Indexed: 11/02/2022]
Abstract
Hepatitis B virus (HBV) and its related protein, HBV X (HBx), play an important role in podocyte injury in HBV-associated glomerulonephritis (HBV-GN). The microRNA MiR-223 is expressed in several diseases, including HBV-associated disease, while the nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome plays a major role in pyroptosis. In this study, we investigated the function and mechanism of action of miR-223 in HBx-induced podocyte pyroptosis. A quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) assay showed that miR-223 was downregulated in HBx-transfected podocytes. Transfection with an miR-223 mimic abolished the expression of the NLRP3 inflammasome and the cytokines that are released as a result of NLRP3 overexpression. Moreover, transfection with HBx and NLRP3 overexpression plasmids increased the expression of pyroptosis-related proteins, especially in the presence of miR-223 inhibitors. Thus, miR-223 downregulation plays an important role in HBx-induced podocyte pyroptosis by targeting the NLRP3 inflammasome, suggesting that miR-223 is a potential therapeutic target for alleviating HBV-GN inflammation.
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Affiliation(s)
- Yani Yu
- Department of Nephrology, The Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong, China
| | - Hui Dong
- Health Management Center, The Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong, China
| | - Yue Zhang
- Department of Stomatology, Qingdao Municipal Hospital Group, Qingdao, 266003, Shandong, China
| | - Jingyi Sun
- Department of Nephrology, The Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong, China
| | - Baoshuang Li
- Department of Nephrology, The Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong, China
| | - Yueqi Chen
- Department of Nephrology, The Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong, China
| | - Moxuan Feng
- Department of Nephrology, The Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong, China
| | - Xiaoqian Yang
- Department of Nephrology, The Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong, China
| | - Shengbo Gao
- Department of Nephrology, The People's Hospital of Changle County, Weifang, 262400, Shandong, China
| | - Wei Jiang
- Department of Nephrology, The Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong, China.
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Curran CS, Kopp JB. RAGE pathway activation and function in chronic kidney disease and COVID-19. Front Med (Lausanne) 2022; 9:970423. [PMID: 36017003 PMCID: PMC9395689 DOI: 10.3389/fmed.2022.970423] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 07/21/2022] [Indexed: 12/23/2022] Open
Abstract
The multi-ligand receptor for advanced glycation end-products (RAGE) and its ligands are contributing factors in autoimmunity, cancers, and infectious disease. RAGE activation is increased in chronic kidney disease (CKD) and coronavirus disease 2019 (COVID-19). CKD may increase the risk of COVID-19 severity and may also develop in the form of long COVID. RAGE is expressed in essentially all kidney cell types. Increased production of RAGE isoforms and RAGE ligands during CKD and COVID-19 promotes RAGE activity. The downstream effects include cellular dysfunction, tissue injury, fibrosis, and inflammation, which in turn contribute to a decline in kidney function, hypertension, thrombotic disorders, and cognitive impairment. In this review, we discuss the forms and mechanisms of RAGE and RAGE ligands in the kidney and COVID-19. Because various small molecules antagonize RAGE activity in animal models, targeting RAGE, its co-receptors, or its ligands may offer novel therapeutic approaches to slowing or halting progressive kidney disease, for which current therapies are often inadequate.
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Affiliation(s)
- Colleen S. Curran
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Jeffrey B. Kopp
- Kidney Disease Section, NIDDK (National Institute of Diabetes and Digestive and Kidney Diseases), National Institutes of Health, Bethesda, MD, United States
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Rysz J, Franczyk B, Rysz-Górzyńska M, Gluba-Brzózka A. Are Alterations in DNA Methylation Related to CKD Development? Int J Mol Sci 2022; 23:ijms23137108. [PMID: 35806113 PMCID: PMC9267048 DOI: 10.3390/ijms23137108] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/17/2022] [Accepted: 06/18/2022] [Indexed: 12/29/2022] Open
Abstract
The modifications in genomic DNA methylation are involved in the regulation of normal and pathological cellular processes. The epigenetic regulation stimulates biological plasticity as an adaptive response to variations in environmental factors. The role of epigenetic changes is vital for the development of some diseases, including atherogenesis, cancers, and chronic kidney disease (CKD). The results of studies presented in this review have suggested that altered DNA methylation can modulate the expression of pro-inflammatory and pro-fibrotic genes, as well those essential for kidney development and function, thus stimulating renal disease progression. Abnormally increased homocysteine, hypoxia, and inflammation have been suggested to alter epigenetic regulation of gene expression in CKD. Studies of renal samples have demonstrated the relationship between variations in DNA methylation and fibrosis and variations in estimated glomerular filtration rate (eGFR) in human CKD. The unravelling of the genetic–epigenetic profile would enhance our understanding of processes underlying the development of CKD. The understanding of multifaceted relationship between DNA methylation, genes expression, and disease development and progression could improve the ability to identify individuals at risk of CKD and enable the choice of appropriate disease management.
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Affiliation(s)
- Jacek Rysz
- Department of Nephrology, Hypertension and Family Medicine, Medical University of Lodz, 113 Żeromskego Street, 90-549 Lodz, Poland; (J.R.); (B.F.)
| | - Beata Franczyk
- Department of Nephrology, Hypertension and Family Medicine, Medical University of Lodz, 113 Żeromskego Street, 90-549 Lodz, Poland; (J.R.); (B.F.)
| | - Magdalena Rysz-Górzyńska
- Department of Otolaryngology, Laryngological Oncology, Audiology and Phoniatrics, Medical Univesity of Lodz, 113 Żeromskego Street, 90-549 Lodz, Poland;
| | - Anna Gluba-Brzózka
- Department of Nephrology, Hypertension and Family Medicine, Medical University of Lodz, 113 Żeromskego Street, 90-549 Lodz, Poland; (J.R.); (B.F.)
- Correspondence:
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Ying C, Zhou Z, Dai J, Wang M, Xiang J, Sun D, Zhou X. Activation of the NLRP3 inflammasome by RAC1 mediates a new mechanism in diabetic nephropathy. Inflamm Res 2022; 71:191-204. [PMID: 35028708 DOI: 10.1007/s00011-021-01532-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 12/02/2021] [Accepted: 12/02/2021] [Indexed: 12/28/2022] Open
Abstract
OBJECTIVE Inflammation is central to the development and progression of diabetic nephropathy (DN). Although the exact mechanisms of inflammation in the kidney have not been well elucidated, pyrin domain containing 3 (NLRP3) inflammasome activation is involved in the onset and progression of DN. Here, we investigated the underlying regulatory mechanisms of hyperglycaemia-induced NLRP3 inflammasome activation in the kidney. METHODS HEK293T cells received high glucose, and the cell proliferation and apoptosis were detected. Biochemical indicators in db/db mice were tested by kits, and the morphological changes in the kidney were observed using staining methods and transmission electron microscopy. The interaction of Ras-related C3 botulinum toxin substrate 1 (RAC1) and NLRP3 inflammasome in cells and in mice was assessed by co-immunoprecipitation (Co-IP) and immunofluorescence. Expression of all proteins was examined by western blotting and immunohistochemistry. In additional, the directly combination of RAC1 and NLRP3 was evaluated by GST Pulldown. RESULTS High-glucose and hyperglycaemia conditions resulted in Ras-related C3 botulinum toxin substrate 1 (RAC1) and NLRP3 inflammasome interactions in cells and in mice. Additionally, RAC1 promoted NLRP3 inflammasome activation and then induced cell damage, and morphological and functional abnormalities in the kidney. We also observed that RAC1 activates the NLRP3 inflammasome by directly binding to NLRP3. CONCLUSION In the present study, we confirmed that RAC1 binding to NLRP3 is sufficient to activate the NLRP3 inflammasome in the kidney and accelerate DN pathological processes. These results elucidate the upstream cellular and molecular mechanisms of NLRP3 inflammasome activation and provide new therapeutic strategies for the treatment of DN.
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Affiliation(s)
- Changjiang Ying
- Department of Endocrinology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221002, Jiangsu, People's Republic of China
| | - Zhongyuan Zhou
- The Graduate School, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China
| | - Jiao Dai
- The Graduate School, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China
| | - Meng Wang
- The Graduate School, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China
| | - Jie Xiang
- Department of Rehabilitation, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221002, Jiangsu, People's Republic of China
| | - Dong Sun
- Department of Nephrology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221002, Jiangsu, People's Republic of China.
| | - Xiaoyan Zhou
- Department of Genetics, School of Life Sciences, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China.
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10
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Zhao W, Zhou L, Novák P, Shi X, Lin CB, Zhu X, Yin K. Metabolic Dysfunction in the Regulation of the NLRP3 Inflammasome Activation: A Potential Target for Diabetic Nephropathy. J Diabetes Res 2022; 2022:2193768. [PMID: 35719709 PMCID: PMC9203236 DOI: 10.1155/2022/2193768] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 03/31/2022] [Accepted: 05/27/2022] [Indexed: 11/18/2022] Open
Abstract
Metabolic dysfunction plays a key role in the development of diabetic nephropathy (DN). However, the exact effects and mechanisms are still unclear. The pyrin domain-containing protein 3 (NLRP3) inflammasome, a member of the nod-like receptor family, is considered a crucial inflammatory regulator and plays important roles in the progress of DN. A growing body of evidence suggests that high glucose, high fat, or other metabolite disorders can abnormally activate the NLRP3 inflammasome. Thus, in this review, we discuss the potential function of abnormal metabolites such as saturated fatty acids (SFAs), cholesterol crystals, uric acid (UA), and homocysteine in the NLRP3 inflammasome activation and explain the potential function of metabolic dysfunction regulation of NLRP3 activation in the progress of DN via regulation of inflammatory response and renal interstitial fibrosis (RIF). In addition, the potential mechanisms of metabolism-related drugs, such as metformin and sodium glucose cotransporter (SGLT2) inhibitors, which have served as the suppressors of the NLRP3 inflammasomes, in DN, are also discussed. A better understanding of NLRP3 inflammasome activation in abnormal metabolic microenvironment may provide new insights for the prevention and treatment of DN.
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Affiliation(s)
- Wenli Zhao
- Department of Cardiology, The Second Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
- Guangxi Key Laboratory of Diabetic Systems Medicine, Guilin Medical University, Guilin, Guangxi, China
- Guangxi Health Commission Key Laboratory of Glucose and Lipid Metabolism Disorders, The Second Affiliated Hospital of Guilin Medical University, Guilin, Guangxi 541199, China
| | - Le Zhou
- Guangxi Key Laboratory of Diabetic Systems Medicine, Guilin Medical University, Guilin, Guangxi, China
| | - Petr Novák
- Guangxi Key Laboratory of Diabetic Systems Medicine, Guilin Medical University, Guilin, Guangxi, China
| | - Xian Shi
- Guangxi Key Laboratory of Diabetic Systems Medicine, Guilin Medical University, Guilin, Guangxi, China
| | - Chuang Biao Lin
- Department of Cardiology, The Second Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
| | - Xiao Zhu
- Guangxi Key Laboratory of Diabetic Systems Medicine, Guilin Medical University, Guilin, Guangxi, China
| | - Kai Yin
- Department of Cardiology, The Second Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
- Guangxi Key Laboratory of Diabetic Systems Medicine, Guilin Medical University, Guilin, Guangxi, China
- Guangxi Health Commission Key Laboratory of Glucose and Lipid Metabolism Disorders, The Second Affiliated Hospital of Guilin Medical University, Guilin, Guangxi 541199, China
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11
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miR-30a-5p promotes glomerular podocyte apoptosis via DNMT1-mediated hypermethylation under hyperhomocysteinemia. Acta Biochim Biophys Sin (Shanghai) 2021; 54:126-136. [PMID: 35130620 PMCID: PMC9909319 DOI: 10.3724/abbs.2021005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Abnormal elevation of homocysteine (Hcy) level is closely related to the development and progression of chronic kidney disease (CKD), with the molecular mechanisms that are not fully elucidated. Given the demonstration that miR-30a-5p is specifically expressed in glomerular podocytes, in the present study we aimed to investigate the role and potential underlying mechanism of miR-30a-5p in glomerular podocyte apoptosis induced by Hcy. We found that elevated Hcy downregulates miR-30a-5p expression in the mice and Hcy-treated podocytes, and miR-30a-5p directly targets the 3'-untranslated region (3'-UTR) of the forkhead box A1 (FOXA1) and overexpression of miR-30a-5p inhibits FOXA1 expression. By nMS-PCR and MassARRAY quantitative methylation analysis, we showed the increased DNA methylation level of miR-30a-5p promoter both and . Meanwhile, dual-luciferase reporter assay showed that the region between --1400 and --921 bp of miR-30a-5p promoter is a possible regulatory element for its transcription. Mechanistic studies indicated that DNA methyltransferase enzyme 1 (DNMT1) is the key regulator of miR-30a-5p, which in turn enhances miR-30a-5p promoter methylation level and thereby inhibits its expression. Taken together, our results revealed that epigenetic modification of miR-30a-5p is involved in glomerular podocyte injury induced by Hcy, providing a diagnostic marker candidate and novel therapeutic target in CKD induced by Hcy.
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12
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Xiong W, Meng XF, Zhang C. NLRP3 Inflammasome in Metabolic-Associated Kidney Diseases: An Update. Front Immunol 2021; 12:714340. [PMID: 34305953 PMCID: PMC8297462 DOI: 10.3389/fimmu.2021.714340] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 06/28/2021] [Indexed: 12/19/2022] Open
Abstract
Metabolic syndrome (MS) is a group of complex metabolic disorders syndrome, which refers to the pathological state of metabolism disorder of protein, fat, carbohydrate and other substances in human body. The kidney is an important organ of metabolism, and various metabolic disorders can lead to the abnormalities in the structure and function of the kidney. The recognition of pathogenesis and treatment measures of renal damage in MS is a very important part for the renal function preserve. Inflammatory response caused by various metabolic factors is a protective mechanism of the body, but persistent inflammation will become a harmful factor and aggravate kidney damage. Inflammasomes are sensors of the innate immune system that play crucial roles in initiating inflammation in response to acute infections and chronic diseases. They are multiprotein complex composed of cytoplasmic sensors (mainly NLR family members), apoptosis-associated speck-like protein (ASC or PYCARD) and pro-caspase-1. After receiving exogenous and endogenous stimuli, the sensors begin to assemble inflammasome and then promote the release of inflammatory cytokines IL-1β and IL-18, resulting in a special way of cell death named pyroptosis. In the kidney, NLRP3 inflammasome can be activated by a variety of pathways, which eventually leads to inflammatory infiltration, renal intrinsic cell damage and renal function decline. This paper reviews the function and specific regulatory mechanism of inflammasome in kidney damage caused by various metabolic disorders, which will provide a new therapeutic perspective and targets for kidney diseases.
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Affiliation(s)
- Wei Xiong
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xian-Fang Meng
- Department of Neurobiology, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chun Zhang
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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13
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Jiang M, Zhao M, Bai M, Lei J, Yuan Y, Huang S, Zhang Y, Ding G, Jia Z, Zhang A. SIRT1 Alleviates Aldosterone-Induced Podocyte Injury by Suppressing Mitochondrial Dysfunction and NLRP3 Inflammasome Activation. KIDNEY DISEASES (BASEL, SWITZERLAND) 2021; 7:293-305. [PMID: 34395544 DOI: 10.1159/000513884] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 12/08/2020] [Indexed: 01/02/2023]
Abstract
BACKGROUND Podocyte injury contributes to progressive glomerulosclerosis. Previously, we demonstrated the important role of the NLR family pyrin domain containing 3 (NLRP3) inflammasome in mediating the podocyte injury induced by aldosterone. Silent mating type information regulation 2 homolog 1 (SIRT1) is an NAD+-dependent deacetylase that is associated with the regulation of cellular inflammation. However, whether the activation of the NLRP3 inflammasome in podocytes is regulated by SIRT1, and the mechanism involved, remains unknown. METHODS In this study, we detected SIRT1 expression in patients with podocyte disease and performed an aldosterone infusion model in podocyte-specific Sirt1 knockout mice. In cultured podocytes, we used plasmids to overexpress SIRT1 and treated the podocyte with aldosterone. RESULTS SIRT1 was significantly decreased in the glomeruli of patients with podocyte disease. Sirt1-deficient mice showed significant urinary albumin excretion after aldosterone infusion, and the severity of the glomerular injury was significantly greater in podocyte-specific Sirt1 knockout mice than in the wild-type mice. Moreover, podocyte conditional Sirt1 knockout aggravated NLRP3 inflammasome activation and mitochondrial dysfunction (MtD). In vitro, overexpression of SIRT1 inhibited NLRP3 activation, protected against MtD and podocyte injury. CONCLUSION Taken together, these findings revealed a novel regulatory mechanism of the NLRP3 inflammasome by SIRT1 by promoting mitochondrial function, which provides some potential targets for the treatment of glomerular diseases.
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Affiliation(s)
- Mingzhu Jiang
- Department of Nephrology, Children's Hospital of Nanjing Medical University, Nanjing, China.,Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
| | - Min Zhao
- Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China.,Department of Nephrology, Nanjing Drum Tower Hospital, Nanjing, China
| | - Mi Bai
- Department of Nephrology, Children's Hospital of Nanjing Medical University, Nanjing, China.,Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
| | - Juan Lei
- Department of Nephrology, Children's Hospital of Nanjing Medical University, Nanjing, China.,Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
| | - Yanggang Yuan
- Department of Nephrology, The First Affiliated Hospital of Nanjing Medical University, Jiangsu Province Hospital, Nanjing, China
| | - Songming Huang
- Department of Nephrology, Children's Hospital of Nanjing Medical University, Nanjing, China.,Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
| | - Yue Zhang
- Department of Nephrology, Children's Hospital of Nanjing Medical University, Nanjing, China.,Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
| | - Guixia Ding
- Department of Nephrology, Children's Hospital of Nanjing Medical University, Nanjing, China.,Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
| | - Zhanjun Jia
- Department of Nephrology, Children's Hospital of Nanjing Medical University, Nanjing, China.,Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
| | - Aihua Zhang
- Department of Nephrology, Children's Hospital of Nanjing Medical University, Nanjing, China.,Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
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14
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Gao W, Liu Y, Fan L, Zheng B, Jefferson JR, Wang S, Zhang H, Fang X, Nguyen BV, Zhu T, Roman RJ, Fan F. Role of γ-adducin in actin cytoskeleton rearrangements in podocyte pathophysiology. Am J Physiol Renal Physiol 2021; 320:F97-F113. [PMID: 33308016 PMCID: PMC7847051 DOI: 10.1152/ajprenal.00423.2020] [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: 08/10/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 12/16/2022] Open
Abstract
We recently reported that the enhanced susceptibility to chronic kidney disease (CKD) in the fawn-hooded hypertensive (FHH) rat is caused, at least in part, by a mutation in γ-adducin (ADD3) that attenuates renal vascular function. The present study explored whether Add3 contributes to the modulation of podocyte structure and function using FHH and FHH.Add3 transgenic rats. The expression of ADD3 on the membrane of primary podocytes isolated from FHH was reduced compared with FHH.Add3 transgenic rats. We found that F-actin nets, which are typically localized in the lamellipodia, replaced unbranched stress fibers in conditionally immortalized mouse podocytes transfected with Add3 Dicer-substrate short interfering RNA (DsiRNA) and primary podocytes isolated from FHH rats. There were increased F/G-actin ratios and expression of the Arp2/3 complexes throughout FHH podocytes in association with reduced synaptopodin and RhoA but enhanced Rac1 and CDC42 expression in the renal cortex, glomeruli, and podocytes of FHH rats. The expression of nephrin at the slit diaphragm and the levels of focal adhesion proteins integrin-α3 and integrin-β1 were decreased in the glomeruli of FHH rats. Cell migration was enhanced and adhesion was reduced in podocytes of FHH rats as well as in immortalized mouse podocytes transfected with Add3 DsiRNA. Mean arterial pressures were similar in FHH and FHH.Add3 transgenic rats at 16 wk of age; however, FHH rats exhibited enhanced proteinuria associated with podocyte foot process effacement. These results demonstrate that reduced ADD3 function in FHH rats alters baseline podocyte pathophysiology by rearrangement of the actin cytoskeleton at the onset of proteinuria in young animals.
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Affiliation(s)
- Wenjun Gao
- Department of Urology, Zhongshan Hospital, Fudan University, Shanghai, China
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Yedan Liu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Letao Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Baoying Zheng
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Joshua R Jefferson
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Shaoxun Wang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Huawei Zhang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Xing Fang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Bond V Nguyen
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Tongyu Zhu
- Department of Urology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
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15
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Xiong W, Meng XF, Zhang C. Inflammasome activation in podocytes: a new mechanism of glomerular diseases. Inflamm Res 2020; 69:731-743. [PMID: 32448973 DOI: 10.1007/s00011-020-01354-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 03/22/2020] [Accepted: 05/05/2020] [Indexed: 12/14/2022] Open
Abstract
INTRODUCTION Inflammasome is a multi-protein complex which is an important constituent of innate immunity. It mainly consists of three parts, apoptosis-associated speck-like protein containing caspase recruitment domain (ASC), caspase protease, and a NOD-like receptor (NLR) family protein (such as NLRP1) or an HIN200 family protein (such as AIM2). Inflammasome is widely studied in many autoimmune diseases and chronic inflammatory reactions, such as familial periodic autoinflammatory response, type 2 diabetes, Alzheimer's disease, and atherosclerosis. Activation of inflammasome in the kidney has been widely reported in glomerular and tubular-interstitial diseases. Podocytes play a critical role in maintaining the normal structure and function of glomerular filtration barrier. Recently, it has been demonstrated that podocytes, as a group of renal residential cells, can express all necessary components of NLRP3 inflammasome, which is activated and contribute to inflammatory response in the local kidney. METHODS Literature review was conducted to further summarize current evidence of podocyte NLRP3 inflammasome activation and related molecular mechanisms under different disease conditions. RESULTS Podocytes are a key component of the glomerular filtration barrier, and the loss of podocyte regeneration is a major limiting factor in the recovery of proteinuria. Through a more comprehensive study of inflammasome in podocytes, it will provide new targets and possibilities for the treatment of kidney diseases.
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Affiliation(s)
- Wei Xiong
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Xian-Fang Meng
- Department of Neurobiology, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
| | - Chun Zhang
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
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Nitrative Stress-Related Autophagic Insufficiency Participates in Hyperhomocysteinemia-Induced Renal Aging. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:4252047. [PMID: 32047576 PMCID: PMC7007752 DOI: 10.1155/2020/4252047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 12/25/2019] [Accepted: 01/10/2020] [Indexed: 11/26/2022]
Abstract
The kidneys are important organs that are susceptible to aging. Hyperhomocysteinemia (HHcy) is a risk factor for nephropathy and is associated with chronic nephritis, purpuric nephritis, and nephrotic syndrome. Numerous studies have shown that elevated serum homocysteine levels can damage the kidneys; however, the underlying mechanism of HHcy on kidney damage remains unclear. In this study, we make use of a diet-induced HHcy rat model and in vitro cell culture to explore the role of autophagy in HHcy-induced renal aging and further explored the underlying mechanism. We demonstrated that HHcy led to the development of renal aging. Promoted kidney aging and autophagic insufficiency were involved in HHcy-induced renal aging. HHcy decreased the expression of transcription factor EB (TFEB), the key transcription factor of autophagy-related genes in renal tissue. Further experiments showed that nitrative stress levels were increased in the kidney of HHcy rats. Interestingly, pretreatment with the peroxynitrite (ONOO−) scavenger FeTMPyP not only reduced the Hcy-induced nitrative stress in vitro but also partially attenuated the decrease in TFEB in both protein and mRNA levels. Moreover, our results indicated that HHcy reduced TFEB expression and inhibited TFEB-mediated autophagy activation by elevating nitrative stress. In conclusion, this study showed an important role of autophagic insufficiency in HHcy-induced renal aging, in which downregulation of TFEB plays a major role. Furthermore, downexpression of TFEB was associated with increased nitrative stress in HHcy. This study provides a novel insight into the mechanism and therapeutic strategy for renal aging.
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