Department of Biochemistry, Basic Medicine College, Hebei University of Chinese Medicine, Shijiazhuang, People's Republic of China.
Hebei Key Laboratory of Chinese Medicine Research on Cardio-Cerebrovascular Disease, Shijiazhuang, People's Republic of China.
Am J Physiol Heart Circ Physiol. 2021 Jan 1;320(1):H458-H468. doi: 10.1152/ajpheart.00366.2020. Epub 2020 Oct 23.
Coronary artery spasm (CAS) is an intense vasoconstriction of coronary arteries that causes total or subtotal vessel occlusion. The cardioprotective effect of sirtuin-1 (SIRT1) has been extensively highlighted in coronary artery diseases. The aims within this study include the investigation of the molecular mechanism by which SIRT1 alleviates CAS. SIRT1 expression was first determined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blot analysis in an endothelin-1 (ET-1)-induced rat CAS model. Interaction among SIRT1, nuclear factor-kappaB (NF-κB), myosin light chain kinase/myosin light chain-2 (MLCK/MLC2), and ET-1 was analyzed using luciferase reporter assay, RT-qPCR, and Western blot analysis. After ectopic expression and depletion experiments in vascular smooth muscle cells (VSMCs), contraction and proliferation of VSMCs and expression of contraction-related proteins (α-SMA, calponin, and SM22α) were measured by collagen gel contraction, 5-ethynyl-2'-deoxyuridine (EdU) assay, RT-qPCR, and Western blot analysis. The obtained results showed that SIRT1 expression was reduced in rat CAS models. However, overexpression of SIRT1 inhibited the contraction and proliferation of VSMCs in vitro. Mechanistic investigation indicated that SIRT1 inhibited NF-κB expression through deacetylation. Moreover, NF-κB could activate the MLCK/MLC2 pathway and upregulate ET-1 expression by binding to their promoter regions, thus inducing VSMC contraction and proliferation in vitro. In vivo experimental results also revealed that SIRT1 alleviated CAS through regulation of the NF-κB/MLCK/MLC2/ET-1 signaling axis. Collectively, our data suggested that SIRT1 could mediate the deacetylation of NF-κB, disrupt the MLCK/MLC2 pathway, and inhibit the expression of ET-1 to relieve CAS, providing a theoretical basis for the prospect of CAS treatment and prevention. Rat coronary artery spasm models exhibit reduced expression of SIRT1. Overexpression of SIRT1 inhibits contraction and proliferation of VSMCs. SIRT1 inhibits NF-κB through deacetylation to modulate VSMC contraction and proliferation. NF-κB activates the MLCK/MLC2 pathway. NF-κB upregulates ET-1 to modulate VSMC contraction and proliferation.
冠状动脉痉挛（CAS）是冠状动脉的强烈血管收缩，导致血管完全或部分闭塞。Sirtuin-1（SIRT1）的心脏保护作用已在冠状动脉疾病中得到广泛强调。本研究的目的包括研究 SIRT1 缓解 CAS 的分子机制。通过逆转录定量聚合酶链反应（RT-qPCR）和 Western blot 分析，首先确定内皮素-1（ET-1）诱导的大鼠 CAS 模型中 SIRT1 的表达。通过荧光素酶报告基因分析、RT-qPCR 和 Western blot 分析，分析 SIRT1、核因子-κB（NF-κB）、肌球蛋白轻链激酶/肌球蛋白轻链-2（MLCK/MLC2）和 ET-1 之间的相互作用。通过胶原凝胶收缩、5-乙炔基-2'-脱氧尿苷（EdU）测定、RT-qPCR 和 Western blot 分析，在血管平滑肌细胞（VSMCs）中进行异位表达和耗尽实验后，测量 VSMCs 的收缩和增殖以及收缩相关蛋白（α-SMA、钙调蛋白和 SM22α）的表达。结果表明，SIRT1 在大鼠 CAS 模型中的表达降低。然而，SIRT1 的过表达抑制了体外 VSMCs 的收缩和增殖。机制研究表明，SIRT1 通过去乙酰化抑制 NF-κB 的表达。此外，NF-κB 可以通过与启动子区域结合激活 MLCK/MLC2 途径并上调 ET-1 的表达，从而在体外诱导 VSMC 收缩和增殖。体内实验结果还表明，SIRT1 通过调节 NF-κB/MLCK/MLC2/ET-1 信号轴缓解 CAS。总之，我们的数据表明，SIRT1 可以介导 NF-κB 的去乙酰化，破坏 MLCK/MLC2 途径，并抑制 ET-1 的表达，从而缓解 CAS，为 CAS 的治疗和预防提供了理论依据。大鼠冠状动脉痉挛模型中 SIRT1 的表达降低。SIRT1 的过表达抑制 VSMCs 的收缩和增殖。SIRT1 通过去乙酰化抑制 NF-κB 来调节 VSMC 的收缩和增殖。NF-κB 激活 MLCK/MLC2 途径。NF-κB 上调 ET-1 来调节 VSMC 的收缩和增殖。
