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Guo P, Tai Y, Wang M, Sun H, Zhang L, Wei W, Xiang YK, Wang Q. Gα 12 and Gα 13: Versatility in Physiology and Pathology. Front Cell Dev Biol 2022; 10:809425. [PMID: 35237598 PMCID: PMC8883321 DOI: 10.3389/fcell.2022.809425] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/17/2022] [Indexed: 01/14/2023] Open
Abstract
G protein-coupled receptors (GPCRs), as the largest family of receptors in the human body, are involved in the pathological mechanisms of many diseases. Heterotrimeric G proteins represent the main molecular switch and receive cell surface signals from activated GPCRs. Growing evidence suggests that Gα12 subfamily (Gα12/13)-mediated signaling plays a crucial role in cellular function and various pathological processes. The current research on the physiological and pathological function of Gα12/13 is constantly expanding, Changes in the expression levels of Gα12/13 have been found in a wide range of human diseases. However, the mechanistic research on Gα12/13 is scattered. This review briefly describes the structural sequences of the Gα12/13 isoforms and introduces the coupling of GPCRs and non-GPCRs to Gα12/13. The effects of Gα12/13 on RhoA and other signaling pathways and their roles in cell proliferation, migration, and immune cell function, are discussed. Finally, we focus on the pathological impacts of Gα12/13 in cancer, inflammation, metabolic diseases, fibrotic diseases, and circulatory disorders are brought to focus.
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Affiliation(s)
- Paipai Guo
- Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Medical University, Hefei, China
| | - Yu Tai
- Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Medical University, Hefei, China
| | - Manman Wang
- Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Medical University, Hefei, China
| | - Hanfei Sun
- Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Medical University, Hefei, China
| | - Lingling Zhang
- Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Medical University, Hefei, China
| | - Wei Wei
- Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Medical University, Hefei, China
| | - Yang K Xiang
- Department of Pharmacology, University of California, Davis, Davis, CA, United States.,VA Northern California Health Care System, Mather, CA, United States
| | - Qingtong Wang
- Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Medical University, Hefei, China
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2
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tRNA-Derived Fragments in Podocytes with Adriamycin-Induced Injury Reveal the Potential Mechanism of Idiopathic Nephrotic Syndrome. BIOMED RESEARCH INTERNATIONAL 2020; 2020:7826763. [PMID: 32685525 PMCID: PMC7330628 DOI: 10.1155/2020/7826763] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/12/2020] [Accepted: 05/29/2020] [Indexed: 11/17/2022]
Abstract
Idiopathic nephrotic syndrome (INS) is a disease involving injury to podocytes in the glomerular filtration barrier, and its specific causes have not been elucidated. Transfer RNA-derived fragments (tRFs), products of precise tRNA cleavage, have been indicated to play critical roles in various diseases. Currently, there is no relevant research on the role of tRFs in INS. This study intends to explore the changes in and importance of tRFs during podocyte injury in vitro and to further analyze the potential mechanism of INS. Differentially expressed tRFs in the adriamycin-treated group were identified by high-throughput sequencing and further verified by quantitative RT-PCR. In total, 203 tRFs with significant differential expression were identified, namely, 102 upregulated tRFs and 101 downregulated tRFs (q < 0.05, ∣log2FC | ≥2). In particular, AS-tDR-008924, AS-tDR-011690, tDR-003634, AS-tDR-013354, tDR-011031, AS-tDR-001008, and AS-tDR-007319 were predicted to be involved in podocyte injury by targeting the Gpr, Wnt, Rac1, and other genes. Furthermore, gene ontology analysis showed that these differential tRFs were strongly associated with podocyte injury processes such as protein binding, cell adhesion, synapses, the actin cytoskeleton, and insulin-activate receptor activity. KEGG pathway analysis predicted that they participated in the PI3K-Akt signaling pathway, Wnt signaling pathway, and Ras signaling pathway. It was reported that these pathways contribute to podocyte injury. In conclusion, our study revealed that changes in the expression levels of tRFs might be involved in INS. Seven of the differentially expressed tRFs might play important roles in the process of podocyte injury and are worthy of further study.
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Tutunea-Fatan E, Lee JC, Denker BM, Gunaratnam L. Heterotrimeric Gα 12/13 proteins in kidney injury and disease. Am J Physiol Renal Physiol 2020; 318:F660-F672. [PMID: 31984793 DOI: 10.1152/ajprenal.00453.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Gα12 and Gα13 are ubiquitous members of the heterotrimeric guanine nucleotide-binding protein (G protein) family that play central and integrative roles in the regulation of signal transduction cascades within various cell types in the kidney. Gα12/Gα13 proteins enable the kidney to adapt to an ever-changing environment by transducing stimuli from cell surface receptors and accessory proteins to effector systems. Therefore, perturbations in Gα12/Gα13 levels or their activity can contribute to the pathogenesis of various renal diseases, including renal cancer. This review will highlight and discuss the complex and expanding roles of Gα12/Gα13 proteins on distinct renal pathologies, with emphasis on more recently reported findings. Deciphering how the different Gα12/Gα13 interaction networks participate in the onset and development of renal diseases may lead to the discovery of new therapeutic strategies.
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Affiliation(s)
- Elena Tutunea-Fatan
- Matthew Mailing Centre for Translational Transplant Studies, Lawson Health Research Institute, London, Ontario, Canada
| | - Jasper C Lee
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Bradley M Denker
- Beth Israel Deaconess Medical Center and Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Lakshman Gunaratnam
- Matthew Mailing Centre for Translational Transplant Studies, Lawson Health Research Institute, London, Ontario, Canada.,Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada.,Division of Nephrology, Department of Medicine, University of Western Ontario, London, Ontario, Canada
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4
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Ansermet C, Centeno G, Nikolaeva S, Maillard MP, Pradervand S, Firsov D. The intrinsic circadian clock in podocytes controls glomerular filtration rate. Sci Rep 2019; 9:16089. [PMID: 31695128 PMCID: PMC6838779 DOI: 10.1038/s41598-019-52682-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 10/21/2019] [Indexed: 12/20/2022] Open
Abstract
Glomerular filtration rate (GFR), or the rate of primary urine formation, is the key indicator of renal function. Studies have demonstrated that GFR exhibits significant circadian rhythmicity and, that these rhythms are disrupted in a number of pathologies. Here, we tested a hypothesis that the circadian rhythm of GFR is driven by intrinsic glomerular circadian clocks. We used mice lacking the circadian clock protein BMAL1 specifically in podocytes, highly specialized glomerular cells critically involved in the process of glomerular filtration (Bmal1lox/lox/Nphs2-rtTA/LC1 or, cKO mice). Circadian transcriptome profiling performed on isolated glomeruli from control and cKO mice revealed that the circadian clock controls expression of multiple genes encoding proteins essential for normal podocyte function. Direct assessment of glomerular filtration by inulin clearance demonstrated that circadian rhythmicity in GFR was lost in cKO mice that displayed an ultradian rhythm of GFR with 12-h periodicity. The disruption of circadian rhythmicity in GFR was paralleled by significant changes in circadian patterns of urinary creatinine, sodium, potassium and water excretion and by alteration in the diurnal pattern of plasma aldosterone levels. Collectively, these results indicate that the intrinsic circadian clock in podocytes participate in circadian rhythmicity of GFR.
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Affiliation(s)
- Camille Ansermet
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Gabriel Centeno
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Svetlana Nikolaeva
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.,Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St-Petersburg, Russia
| | - Marc P Maillard
- Service of Nephrology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Sylvain Pradervand
- Genomic Technologies Facility, University of Lausanne, Lausanne, Switzerland
| | - Dmitri Firsov
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.
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Wen J, Lin X, Gao W, Qu B, Zuo Y, Liu R, Yu M. Inhibition of LPA1 Signaling Impedes Conversion of Human Tenon's Fibroblasts into Myofibroblasts Via Suppressing TGF-β/Smad2/3 Signaling. J Ocul Pharmacol Ther 2019; 35:331-340. [DOI: 10.1089/jop.2018.0120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Affiliation(s)
- Jiamin Wen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Xianchai Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Wuyou Gao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Bo Qu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Yajing Zuo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Rongjiao Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Minbin Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, People's Republic of China
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Parrish AR. The cytoskeleton as a novel target for treatment of renal fibrosis. Pharmacol Ther 2016; 166:1-8. [PMID: 27343756 DOI: 10.1016/j.pharmthera.2016.06.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 06/07/2016] [Indexed: 12/23/2022]
Abstract
The incidence of chronic kidney disease (CKD) is increasing, with an estimated prevalence of 12% in the United States (Synder et al., 2009). While CKD may progress to end-stage renal disease (ESRD), which necessitates renal replacement therapy, i.e. dialysis or transplantation, most CKD patients never reach ESRD due to the increased risk of death from cardiovascular disease. It is well-established that regardless of the initiating insult - most often diabetes or hypertension - fibrosis is the common pathogenic pathway that leads to progressive injury and organ dysfunction (Eddy, 2014; Duffield, 2014). As such, there has been extensive research into the molecular and cellular mechanisms of renal fibrosis; however, translation to effective therapeutic strategies has been limited. While a role for the disruption of the cytoskeleton, most notably the actin network, has been established in acute kidney injury over the past two decades, a role in regulating renal fibrosis and CKD is only recently emerging. This review will focus on the role of the cytoskeleton in regulating pro-fibrotic pathways in the kidney, as well as data suggesting that these pathways represent novel therapeutic targets to manage fibrosis and ultimately CKD.
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Affiliation(s)
- Alan R Parrish
- Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO 65212, USA.
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Liu J, Li QX, Wang XJ, Zhang C, Duan YQ, Wang ZY, Zhang Y, Yu X, Li NJ, Sun JP, Yi F. β-Arrestins promote podocyte injury by inhibition of autophagy in diabetic nephropathy. Cell Death Dis 2016; 7:e2183. [PMID: 27054338 PMCID: PMC4855668 DOI: 10.1038/cddis.2016.89] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 03/01/2016] [Accepted: 03/03/2016] [Indexed: 11/16/2022]
Abstract
β-Arrestins are multifunctional proteins originally identified as negative adaptors of G protein-coupled receptors (GPCRs). Emerging evidence has also indicated that β-arrestins can activate signaling pathways independent of GPCR activation. This study was to elucidate the role of β-arrestins in diabetic nephropathy (DN) and hypothesized that β-arrestins contribute to diabetic renal injury by mediating podocyte autophagic process. We first found that both β-arrestin-1 and β-arrestin-2 were upregulated in the kidney from streptozotocin-induced diabetic mice, diabetic db/db mice and kidney biopsies from diabetic patients. We further revealed that either β-arrestin-1 or β-arrestin-2 deficiency (Arrb1−/− or Arrb2−/−) ameliorated renal injury in diabetic mice. In vitro, we observed that podocytes increased both β-arrestin-1 and β-arrestin-2 expression levels under hyperglycemia condition and further demonstrated that β-arrestin-1 and β-arrestin-2 shared common mechanisms to suppress podocyte autophagy by negative regulation of ATG12–ATG5 conjugation. Collectively, this study for the first time demonstrates that β-arrestin-1 and β-arrestin-2 mediate podocyte autophagic activity, indicating that β-arrestins are critical components of signal transduction pathways that link renal injury to reduce autophagy in DN. Modulation of these pathways may be an innovative therapeutic strategy for treating patients with DN.
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Affiliation(s)
- J Liu
- Department of Pharmacology, Shandong University School of Medicine, Jinan 250012, China
| | - Q X Li
- Department of Pharmacology, Shandong University School of Medicine, Jinan 250012, China
| | - X J Wang
- Department of Pharmacology, Shandong University School of Medicine, Jinan 250012, China
| | - C Zhang
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Y Q Duan
- Department of Pharmacology, Shandong University School of Medicine, Jinan 250012, China
| | - Z Y Wang
- Department of Pharmacology, Shandong University School of Medicine, Jinan 250012, China
| | - Y Zhang
- Department of Pharmacology, Shandong University School of Medicine, Jinan 250012, China
| | - X Yu
- Department of Physiology, Shandong University School of Medicine, Jinan 250012, China
| | - N J Li
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - J P Sun
- Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan 250012, China
| | - F Yi
- Department of Pharmacology, Shandong University School of Medicine, Jinan 250012, China.,Institute of Nephrology, Shandong University, Jinan 250012, China
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8
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Stimulation of Dopamine D3 Receptor Attenuates Renal Ischemia-Reperfusion Injury via Increased Linkage With Gα12. Transplantation 2016; 99:2274-84. [PMID: 25989500 DOI: 10.1097/tp.0000000000000762] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND Renal ischemia-reperfusion (I/R) injury causes renal tubular necrosis, apoptosis, and inflammation leading to acute renal dysfunction. Recent studies have revealed that deletion of Gα12 mitigates the renal damage due to I/R injury. Our previous study showed that activation of dopamine D3 receptor (D3R) increased its linkage with Gα12, and hampered Gα12-mediated stimulation of renal sodium transport. In the present study, we used an in-vivo rat model and an in vitro study of the renal epithelial cell line (NRK52E) to investigate whether or not an increased linkage between D3R and Gα12 contributes to the protective effect of D3R on renal I/R injury. METHODS For in vivo studies, I/R injury was induced in a rat renal unilateral clamping model. For in vitro studies, hypoxia/reoxygenation and cold storage/rewarming injuries were performed in NRK52E cells. PD128907, a D3R agonist, or vehicle, was administered 15 minutes before clamping (or hypoxia) in both the in vivo or in vitro studies. RESULTS In the rat renal unilateral clamping model, pretreatment with PD128907 (0.2 mg/kg, intravenous) protected against renal I/R injury and increased survival rate during a long-term follow-up after 7 days. A decrease in the generation of reactive oxygen species, apoptosis, and inflammation may be involved in the D3R-mediated protection because pretreatment with PD128907 increased renal glutathione and superoxide dismutase levels and decreased malondialdehyde levels in the I/R group. The increase in cytokines (TNF-α, IL-1β, and IL-10) and myeloperoxidase in I/R injured kidney was also prevented with a simultaneous decrease in the apoptosis of the epithelial cells and expression of apoptosis biomarkers in kidney harvested 1 day after I/R injury. The increase in the coimmunoprecipitation between D3R and Gα12 with D3R stimulation paralleled the observed renal protection from I/R injury. Moreover, in vitro studies showed that transient overexpression of Gα12 in the NRK52E cells attenuated the protective effect of PD128907 on hypoxia/reoxygenation injury. The protective effect of PD128907 might be of significance to renal transplantation because cold storage/rewarming induced injury increased lactate dehydrogenase release and decreased cell viability in NRK52E cells. Conversely, in the presence of PD128907, the increased lactate dehydrogenase release and decreased cell viability were reversed. CONCLUSIONS These results suggest that activation of D3R, by decreasing Gα12-induced renal damage, may exert a protective effect from I/R injury.
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9
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Park F. Accessory proteins for heterotrimeric G-proteins in the kidney. Front Physiol 2015; 6:219. [PMID: 26300785 PMCID: PMC4528294 DOI: 10.3389/fphys.2015.00219] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 07/20/2015] [Indexed: 11/17/2022] Open
Abstract
Heterotrimeric G-proteins play a fundamentally important role in regulating signal transduction pathways in the kidney. Accessory proteins are being identified as direct binding partners for heterotrimeric G-protein α or βγ subunits to promote more diverse mechanisms by which G-protein signaling is controlled. In some instances, accessory proteins can modulate the signaling magnitude, localization, and duration following the activation of cell membrane-associated receptors. Alternatively, accessory proteins complexed with their G-protein α or βγ subunits can promote non-canonical models of signaling activity within the cell. In this review, we will highlight the expression profile, localization and functional importance of these newly identified accessory proteins to control the function of select G-protein subunits under normal and various disease conditions observed in the kidney.
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Affiliation(s)
- Frank Park
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center Memphis, TN, USA
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10
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Abstract
Heterotrimeric G proteins play a crucial role in regulating signal processing to maintain normal cellular homeostasis, and subtle perturbations in its activity can potentially lead to the pathogenesis of renal disorders or diseases. Cell-surface receptors and accessory proteins, which normally modify and organize the coupling of individual G protein subunits, contribute to the regulation of heterotrimeric G protein activity and their convergence and/or divergence of downstream signaling initiated by effector systems. Activators of G protein signaling (AGS) are a family of accessory proteins that intervene at multiple distinct points during the activation-inactivation cycle of G proteins, even in the absence of receptor stimulation. Perturbations in the expression of individual AGS proteins have been reported to modulate signal transduction pathways in a wide array of diseases and disorders within the brain, heart, immune system, and more recently, the kidney. This review will provide an overview of the expression profile, localization, and putative biologic role of the AGS family in the context of normal and diseased states of the kidney.
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Affiliation(s)
- Frank Park
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee
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11
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Woo SH, Sigdel TK, Dinh VT, Vu MT, Sarwal MM, Lafayette RA. Mapping novel immunogenic epitopes in IgA nephropathy. Clin J Am Soc Nephrol 2014; 10:372-81. [PMID: 25542908 DOI: 10.2215/cjn.02390314] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND OBJECTIVES IgA plays a key role in IgA nephropathy (IgAN) by forming immune complexes and depositing in the glomeruli, leading to an inflammatory response. However, the antigenic targets and functional characterization of IgA have been incompletely defined in this disease. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This study was performed in sera from patients who were studied as part of a prospective, observational study of IgAN. These patients (n=22) all had biopsy-proven IgAN within 3 years of study initiation, complete clinical data, annual urinary inulin clearance for GFRs, and at least 5 years of follow-up. Progression was defined as loss of >5 ml/min per 1.73 m(2) per year of inulin clearance measured over at least 5 years. A protein microarray was used for detection of IgAN-specific IgA autoantibodies in blood across approximately 9000 human antigens to specifically identify the most immunogenic protein targets that drive IgA antibodies in IgAN (n=22), healthy controls (n=10), and non-IgAN glomerular diseases (n=17). Results were validated by ELISA assays in sera and by immunohistochemistry in IgAN kidney biopsies. IgA-specific antibodies were correlated with clinical and histologic variables to assess their effect on disease progression and prognosis. RESULTS Fifty-four proteins mounted highly significant IgA antibody responses in patients with IgAN with a false discovery rate (q value) of ≤10%; 325 antibodies (P≤0.05) were increased overall. Antitissue transglutaminase IgA was significantly elevated in IgAN (P<0.001, q value of 0%). IgA antibodies to DDX4 (r=-0.55, P=0.01) and ZADH2 (r=-0.48, P=0.02) were significantly correlated with the decline of renal function. Specific IgA autoantibodies are elevated in IgAN compared with normal participants and those with other glomerular diseases. CONCLUSIONS In this preliminary study, IgA autoantibodies target novel proteins, highly expressed in the kidney glomerulus and tubules. These IgA autoantibodies may play important roles in the pathogenesis of IgAN.
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Affiliation(s)
- Sang Hoon Woo
- Division of Hospital Medicine, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Tara K Sigdel
- Department of Surgery, University of California, San Francisco, California
| | - Van T Dinh
- Department of Surgery, University of California, San Francisco, California
| | - Minh-Thien Vu
- Department of Surgery, University of California, San Francisco, California
| | - Minnie M Sarwal
- Department of Surgery, University of California, San Francisco, California;
| | - Richard A Lafayette
- Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Stanford University, Stanford, California
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12
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Gao N, Wang H, Zhang X, Yang Z. The inhibitory effect of angiotensin II on BKCa channels in podocytes via oxidative stress. Mol Cell Biochem 2014; 398:217-22. [PMID: 25234195 DOI: 10.1007/s11010-014-2221-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 09/13/2014] [Indexed: 01/11/2023]
Abstract
Angiotensin II (Ang II) is an important active substance of the renin-angiotensin system (RAS). The present study has confirmed that abnormalities of Ang II may be related with cerebrovascular diseases, endocrine diseases, cardiovascular diseases, liver diseases, such as: cerebral hypoxia, diabetes, obesity, atrial fibrillation, and liver cirrhosis. However, understanding effects of Ang II on podocytes is not enough. This study was to investigate the effects of oxidative stress on the large conductance, Ca(2+)-activated K(+) channels (BKCa). Results from the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay showed that Ang II induced podocyte death in a concentration-dependent manner. The measurement of superoxide dismutase (SOD) generation demonstrated that Ang II decreased the total SOD of cellular levels. Meaningfully, pretreatment of a type of ROS scavenger formulations named N-(mercaptopropionyl)-glycine (N-MPG) could inhibit podocyte apoptosis induced by Ang II. Meanwhile, patch-clamp technique was used in this study to detect the effects of Ang II on currents of BKCa channel in podocytes. The results indicated that Ang II inhibited the current amplitude of BKCa channel and decreased the slope of I-V curve. Ang II also made the activation curves of BKCa channel shift to the left. These results may provide a theoretical basis for potential treatment of chronic glomerular disease in the future.
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Affiliation(s)
- Na Gao
- School of Medicine, State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Tumor Microenvironment and Neurovascular Regulation, Nankai University, Tianjin, 300071, China
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Pro-fibrotic activity of lysophosphatidic acid in adipose tissue: in vivo and in vitro evidence. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:88-96. [PMID: 24120919 DOI: 10.1016/j.bbalip.2013.10.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 09/05/2013] [Accepted: 10/01/2013] [Indexed: 02/06/2023]
Abstract
Lysophosphatidic acid (LPA) is a pro-fibrotic mediator acting via specific receptors (LPARs) and is synthesized by autotaxin, that increases with obesity. We tested whether LPA could play a role in adipose tissue (AT)-fibrosis associated with obesity. Fibrosis [type I, III, and IV collagens (COL), fibronectin (FN), TGFβ, CTGF and αSMA] and inflammation (MCP1 and F4/80) markers were quantified: (i) in vivo in inguinal (IAT) and perigonadic (PGAT) AT from obese-diabetic db/db mice treated with the LPAR antagonist Ki16425 (5mg/kg/day ip for 7 weeks); and (ii) in vitro in human AT explants in primary culture for 72h in the presence of oleoyl-LPA (10μM) and/or Ki16425 (10μM) and/or the HIF-1α inhibitor YC-1 (100μM). Treatment of db/db mice with Ki16425 reduced Col I and IV mRNAs in IAT and PGAT while Col III mRNAs were only reduced in IAT. This was associated with reduction of COL protein staining in both IAT and PGAT. AT explants showed a spontaneous and time-dependent increase in ATX expression and production of LPA in the culture medium, along with increased levels of Col I and III, TGFβ and αSMA mRNAs and of COL protein staining. In vitro fibrosis was blocked by Ki16425 and was further amplified by oleoyl-LPA. LPA-dependent in vitro fibrosis was blocked by co-treatment with YC1. Our results show that endogenous and exogenous LPA exert a pro-fibrotic activity in AT in vivo and in vitro. This activity could be mediated by an LPA1R-dependent pathway and could involve HIF-1α.
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Zhou TB, Wu WF, Qin YH, Yin SS. Association of all-trans retinoic acid treatment with the renin-angiotensin aldosterone system expression in glomerulosclerosis rats. J Renin Angiotensin Aldosterone Syst 2012; 14:299-307. [PMID: 23144044 DOI: 10.1177/1470320312465220] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND AND OBJECTIVE All-trans retinoic acid (ATRA), a promising therapeutic agent, has been confirmed in animal experiments as playing a protective role against renal diseases. The renin-angiotensin aldosterone system (RAAS) plays a key role in the pathogenesis of renal diseases, and RAAS inhibitors can prevent the progression of kidney diseases. In our previous study, we found that ATRA could play a protective role against glomerulosclerosis (GS) lesions in rats, and its effect was similar to RAAS inhibitors. However, whether ATRA treatment was associated with RAAS expression was not clear. METHODS Six-week-old male Wistar rats were divided into three groups: sham operation group (SHO), glomerulosclerosis model group without treatment (GS) and GS model group treated with ATRA (GA). At the end of 13 weeks, the relevant samples were collected and analyzed. RESULTS The mRNA and protein expression of angiotensin-converting enzyme 1 (ACE1) in the GS group was notably higher when compared with the SHO group. However, mRNA and protein expression of ACE1 in the ATRA treatment group was markedly down-regulated when compared with the GS group. Angiotensin-converting enzyme 2 (ACE2) expression (mRNA or protein) in the GS group was reduced compared with that in the SHO group, and ATRA markedly increased the mRNA and protein expression of ACE2 compared with the GS group. The levels of protein expression of angiotensin I and angiotensin II were significantly up-regulated in the GS group compared with those in the SHO group, and ATRA reduced their expression in the GA group when compared with the GS group. CONCLUSION ATRA is associated with RAAS expression in GS rats, but its detailed mechanism needs to be elucidated by further research.
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Affiliation(s)
- Tian-Biao Zhou
- 1Department of Pediatric Nephrology, The First Affiliated Hospital of GuangXi Medical University, Nanning, Guangxi, China
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H2O2 activates G protein, α 12 to disrupt the junctional complex and enhance ischemia reperfusion injury. Proc Natl Acad Sci U S A 2012; 109:6680-5. [PMID: 22493269 DOI: 10.1073/pnas.1116800109] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The epithelial cell tight junction separates apical and basolateral domains and is essential for barrier function. Disruption of the tight junction is a hallmark of epithelial cell damage and can lead to end organ damage including renal failure. Herein, we identify Gα12 activation by H(2)O(2) leading to tight junction disruption and demonstrate a critical role for Gα12 activation during bilateral renal ischemia/reperfusion injury. Madin-Darby canine kidney (MDCK) cells with inducible Gα12 (Gα12-MDCK) and silenced Gα12 (shGα12-MDCK) were subjected to ATP depletion/repletion and H(2)O(2)/catalase as models of tight junction disruption and recovery by monitoring transepithelial resistance. In ATP depleted cells, barrier disruption and recovery was not affected by Gα12, but reassembly was accelerated by Gα12 depletion. In contrast, silencing of Gα12 completely protected cells from H(2)O(2)-stimulated barrier disruption, a response that rapidly occurred in control cells. H(2)O(2) activated Src and Rho, and Src inhibition (by PP2), but not Rho (by Y27632), protected cells from H(2)O(2)-mediated barrier disruption. Immunofluorescent and biochemical analysis showed that H(2)O(2) led to increased tyrosine phosphorylation of numerous proteins and altered membrane localization of tight junction proteins through Gα12/Src signaling pathway. Gα12 and Src were activated in vivo during ischemia/reperfusion injury, and transgenic mice with renal tubular QLα12 (activated mutant) expression were delayed in recovery and showed more extensive injury. Conversely, Gα12 knockout mice were nearly completely protected from ischemia/reperfusion injury. Taken together, these studies reveal that ROS stimulates Gα12 to activate injury pathways and identifies a therapeutic target for ameliorating ROS mediated injury.
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