金属蛋白酶组织抑制剂-4(一种新型过氧化物酶体增殖物激活受体γ靶基因)在醋酸脱氧皮质酮-盐性高血压中对平滑肌的保护作用

Protective Role for Tissue Inhibitor of Metalloproteinase-4, a Novel Peroxisome Proliferator-Activated Receptor-γ Target Gene, in Smooth Muscle in Deoxycorticosterone Acetate-Salt Hypertension.

作者信息

Ketsawatsomkron Pimonrat, Keen Henry L, Davis Deborah R, Lu Ko-Ting, Stump Madeliene, De Silva T Michael, Hilzendeger Aline M, Grobe Justin L, Faraci Frank M, Sigmund Curt D

机构信息

From the Department of Pharmacology, Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City; and Iowa City Veterans Affairs Healthcare System, IA.

出版信息

Hypertension. 2016 Jan;67(1):214-22. doi: 10.1161/HYPERTENSIONAHA.115.06391. Epub 2015 Nov 23.

Abstract

Loss of peroxisome proliferator-activated receptor-γ (PPARγ) function causes hypertension, whereas its activation lowers blood pressure. Evidence suggests that these effects may be attributable to PPARγ activity in the vasculature. However, the specific transcriptional targets of PPARγ in vessels remain largely unidentified. In this study, we examined the role of smooth muscle PPARγ during salt-sensitive hypertension and investigated its transcriptional targets and functional effect. Transgenic mice expressing dominant-negative PPARγ (S-P467L) in smooth muscle cells were more prone to deoxycorticosterone acetate-salt-induced hypertension and mesenteric arterial dysfunction compared with nontransgenic controls. Despite similar morphometry at baseline, vascular remodeling in conduit and small arteries was enhanced in S-P467L after deoxycorticosterone acetate-salt treatment. Gene expression profiling in aorta and mesenteric arteries revealed significantly decreased expression of tissue inhibitor of metalloproteinase-4 (TIMP-4) in S-P467L. Expression of TIMP-4 was increased by deoxycorticosterone acetate-salt treatment, but this increase was ablated in S-P467L. Interference with PPARγ activity either by treatment with a PPARγ inhibitor, GW9662, or by expressing P467L PPARγ markedly suppressed TIMP-4 in primary smooth muscle cells. PPARγ binds to a PPAR response element (PPRE) in chromatin close to the TIMP-4 gene in smooth muscle cells, suggesting that TIMP-4 is a novel target of PPARγ. The interference with PPARγ and decrease in TIMP-4 were accompanied by an increase in total matrix metalloproteinase activity. PPARγ-mediated loss of TIMP-4 increased, whereas overexpression of TIMP-4 decreased smooth muscle cell migration in a scratch assay. Our findings highlight a protective mechanism induced by PPARγ in deoxycorticosterone acetate-salt treatment, establishing a novel mechanistic link between PPARγ and TIMP-4.

摘要

过氧化物酶体增殖物激活受体γ(PPARγ)功能丧失会导致高血压,而其激活则会降低血压。有证据表明,这些效应可能归因于PPARγ在脉管系统中的活性。然而,PPARγ在血管中的具体转录靶点仍 largely 未被确定。在本研究中,我们研究了平滑肌PPARγ在盐敏感性高血压中的作用,并调查了其转录靶点和功能效应。与非转基因对照相比,在平滑肌细胞中表达显性负性PPARγ(S-P467L)的转基因小鼠更易患醋酸脱氧皮质酮-盐诱导的高血压和肠系膜动脉功能障碍。尽管在基线时形态测量相似,但在醋酸脱氧皮质酮-盐处理后,S-P467L中导管和小动脉的血管重塑增强。主动脉和肠系膜动脉的基因表达谱显示,S-P467L中金属蛋白酶组织抑制剂-4(TIMP-4)的表达显著降低。醋酸脱氧皮质酮-盐处理可增加TIMP-4的表达,但在S-P467L中这种增加被消除。用PPARγ抑制剂GW9662处理或表达P467L PPARγ干扰PPARγ活性,均显著抑制原代平滑肌细胞中的TIMP-4。PPARγ与平滑肌细胞中靠近TIMP-4基因的染色质中的PPAR反应元件(PPRE)结合,表明TIMP-4是PPARγ的一个新靶点。对PPARγ的干扰和TIMP-4的减少伴随着总基质金属蛋白酶活性的增加。PPARγ介导的TIMP-4缺失增加,而TIMP-4的过表达在划痕试验中降低了平滑肌细胞迁移。我们的发现突出了PPARγ在醋酸脱氧皮质酮-盐处理中诱导的一种保护机制,建立了PPARγ与TIMP-4之间的一种新的机制联系。

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