Abstract 372: Role of Redox-Sensitive Calcium Channel TRPM2 and Oxidative Stress in Vascular Smooth Muscle Cell Differentiation to an Osteogenic Phenotype: Implications in Hypertension.

Hypertension ◽  
2012 ◽  
Vol 60 (suppl_1) ◽  
Author(s):  
Augusto C Montezano ◽  
Hiba Yusuf ◽  
Glaucia E Callera ◽  
Rhian M Touyz

Vascular smooth muscle cell (VSMC) transformation to an osteoblast-like phenotype is a major factor contributing to vascular calcification, often associated with chronic kidney disease and hypertension. Exact molecular mechanisms underlying VSMC transformation remain unclear but intracellular calcium and ROS have been implicated. Whether these factors are interlinked is unknown. Here, we tested the hypothesis that ROS and redox-sensitive calcium channels (TRPM2) induce an osteogenic phenotype transition in VSMCs from WKY and SHRSP rats. Cultured VSMCs from WKY and SHRSP rats were exposed to calcification medium (CaM) (Ca2+ 1.8 mmol/L, PO4 2.0 mmol/L) for 10 days in the presence/absence of tempol (superoxide dismutase mimetic), and N-(p-amylcinnamoyl)anthranilic acid (ACA, TRPM2 inhibitor). Osteocalcin (OC), BMP-2, BMP-7, TRPM2 and TRPM2-S expression, as well as p47 phox translocation (cytosol:membrane), were determined by immunoblotting. ROS generation was evaluated by chemioluminescence. ROS production (Ctl: 30 AU/ug protein; CaM: 60 AU/ug protein, p<0.05) and p47 translocation (Ctl: 0.7 AU; CaM: 1.1AU, p<0.05) were increased by the CaM in VSMCs from WKY. CaM-induced increase in OC (Ctl: 5 AU; CaM: 13 AU) and BMP-2 (Ctl: 0.60 AU; CaM: 0.75AU) (p<0.05), followed by a decrease in BMP-7 (Ctl: 1.12 AU; CaM: 0.7 AU) (p<0.05), expression in VSMCs from WKY; an effect that was inhibited by tempol and ACA. In SHRSP, the increase in OC (Ctl: 1.25 AU; CaM: 2 AU) and BMP-2 (Ctl: 0.6 AU; CaM: 0.85 AU, p<0.05) expression induced by the CaM was also blocked by tempol. TRPM2 expression was higher in SHRSP (1.40 AU) than in WKY (1.05 AU) VSMCs (p<0.05). However, TRPM2-S expression, an intracellular inhibitor of TRPM2, was decreased in SHRSP compared to WKY VSMCs (SHRSP: 0.9 AU; WKY: 1.5 AU; p<0.05), and it was further decreased by the CaM (0.6 AU). In conclusion, ROS, through TRPM-2 sensitive mechanisms, seems to play an important role in VSMC transformation to an osteogenic, a phenomenon that may be exacerbated in hypertension.

2020 ◽  
Vol 28 (1) ◽  
pp. 152-168
Author(s):  
Zhi-Xiang Zhou ◽  
Zhong Ren ◽  
Bin-Jie Yan ◽  
Shun-Lin Qu ◽  
Zhi-Han Tang ◽  
...  

: Atherosclerosis is a chronic inflammatory vascular disease. Atherosclerotic cardiovascular disease is the main cause of death in both developed and developing countries. Many pathophysiological factors, including abnormal cholesterol metabolism, vascular inflammatory response, endothelial dysfunction and vascular smooth muscle cell proliferation and apoptosis, contribute to the development of atherosclerosis and the molecular mechanisms underlying the development of atherosclerosis are not fully understood. Ubiquitination is a multistep post-translational protein modification that participates in many important cellular processes. Emerging evidence suggests that ubiquitination plays important roles in the pathogenesis of atherosclerosis in many ways, including regulation of vascular inflammation, endothelial cell and vascular smooth muscle cell function, lipid metabolism and atherosclerotic plaque stability. This review summarizes important contributions of various E3 ligases to the development of atherosclerosis. Targeting ubiquitin E3 ligases may provide a novel strategy for the prevention of the progression of atherosclerosis.


2010 ◽  
Vol 107 (6) ◽  
pp. 787-799 ◽  
Author(s):  
Takashi Ashino ◽  
Varadarajan Sudhahar ◽  
Norifumi Urao ◽  
Jin Oshikawa ◽  
Gin-Fu Chen ◽  
...  

2010 ◽  
Vol 344 (1-2) ◽  
pp. 81-89 ◽  
Author(s):  
Wei-Wen Kuo ◽  
Jing-Ru Weng ◽  
Chih-Yang Huang ◽  
Chang-Hai Tsai ◽  
Wei-Hung Liu ◽  
...  

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Mengxue Zhang ◽  
Bowen Wang ◽  
Craig Kent ◽  
Lian-Wang Guo

Introduction: Intimal hyperplasia (IH) occurs primarily due to vascular smooth muscle cell (SMC) transformation from quiescent to pathogenic phenotypes (e.g. proliferation and inflammation). Identification and effective targeting of key epigenetic factors governing SMC pathogenic transformation may lead to novel therapeutic methods for prevention of IH. We previously found that globally blocking the bromo- and extra-terminal (BET) epigenetic “reader” family abrogated SMC phenotype transformation and IH. We further investigated the functions of the two BET bromodomains (Bromo1 and Bromo2). Hypothesis: Bromo1 and Bromo2 play different roles in SMC pathogenic transformation. Methods and Results: We pre-treated rat primary aortic SMCs (for 2h) with Olinone or RVX208, inhibitors specific for Bromo1 and Bromo2 respectively, and then stimulated SMC phenotype transformation. Whereas RVX208 abrogated PDGF-BB-stimulated SMC proliferation (BrdU assay) in a dose dependent manner, Olinone enhanced SMC proliferation at high concentrations (>20 μM). RVX208 at 50 μM reduced TNFα-induced SMC inflammation (MCP-1 ELISA) by 80%,but Olinone at the same concentration slightly increased MCP-1. Furthermore, whereas RVX208 abolished PDGF-BB or TNFα-induced STAT3 phosphorylation (Western blotting), Olinone slightly increased phospho-STAT3. Conclusions: Our results reveal that blocking two BET bromodomains respectively produces distinct effects on SMC phenotype transformation, suggesting their differential epigenetic functions. Further elucidation of the underlying molecular mechanisms should contribute to precise targeting of the BET family for optimal mitigation of IH.


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