Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China.
Department of intensive Care Unit, Affiliated People' Hospital of Jiangsu University, Zhenjiang, China.
J Physiol Biochem. 2020 Feb;76(1):147-157. doi: 10.1007/s13105-020-00729-1. Epub 2020 Feb 10.
Low shear stress (LSS) occurs in areas where atherosclerosis is prevalent. Many studies have revealed that signal transducer and activator of transcription 1 (STAT1) plays a significant role in cardiovascular disease. Nonetheless, the mechanism underlying the connection between STAT1 and LSS is not fully understood. The purpose of this study was to investigate the link between LSS and STAT1 in endothelial cells (ECs). Monolayer endothelial cells were stimulated or not stimulated by LSS. Protein expression and phosphorylation levels were determined by western blotting. Immunofluorescence was used to compare the protein expression differences in bifurcated and non-bifurcated human coronary arteries. Endothelial function was assessed by using a dihydroethidium assay, real-time PCR, western blotting and nitric oxide (NO)-sensitive fluorophore. Results showed that STAT1 played a key role in LSS-induced endothelium damage. Firstly, LSS activated STAT1, as evidenced by LSS-induced STAT1 (Tyr701) phosphorylation in ECs in vitro and the increased intimal STAT1 expression at bifurcation of human coronary arteries. Secondly, LSS-induced STAT1 phosphorylation was positively regulated by inhibitor of nuclear factor kappa-B kinase ε (IKKε). Additionally, LSS-promoted inflammatory factor expression was markedly reversed by silencing STAT1 (siSTAT1). LSS also increased reactive oxygen species (ROS) level and decreased endogenous NO release: however, siSTAT1 reversed these adverse effects through upregulating the antioxidant gene heme oxygenase-1(HO-1) and downregulating endothelial nitric oxide synthase (eNOS) Thr495 phosphorylation. According to our results, LSS-mediated EC injury may be associated with the activation of STAT1. Strategies designed to reduce STAT1 expression or inhibit STAT1 activation may be effective approaches for reducing the incidence of atherosclerosis.
低切应力（LSS）发生在动脉粥样硬化普遍存在的区域。许多研究表明，信号转导和转录激活因子 1（STAT1）在心血管疾病中起着重要作用。然而，STAT1 与 LSS 之间的联系的机制尚不完全清楚。本研究旨在探讨 LSS 与内皮细胞（ECs）中 STAT1 之间的联系。单层内皮细胞是否受到 LSS 的刺激。通过 Western blot 测定蛋白质表达和磷酸化水平。免疫荧光比较分叉和非分叉人冠状动脉中蛋白质表达的差异。通过二氢乙啶测定、实时 PCR、Western blot 和一氧化氮（NO）敏感荧光探针评估内皮功能。结果表明，STAT1 在 LSS 诱导的内皮损伤中起关键作用。首先，LSS 激活了 STAT1，这可以从体外 ECs 中 LSS 诱导的 STAT1（Tyr701）磷酸化以及人冠状动脉分叉处内膜 STAT1 表达增加得到证明。其次，LSS 诱导的 STAT1 磷酸化受核因子 kappa-B 激酶ε（IKKε）抑制剂的正向调节。此外，沉默 STAT1（siSTAT1）显著逆转了 LSS 诱导的炎症因子表达。LSS 还增加了活性氧（ROS）水平并降低了内源性 NO 释放：然而，siSTAT1 通过上调抗氧化基因血红素加氧酶-1（HO-1）和下调内皮型一氧化氮合酶（eNOS）Thr495 磷酸化逆转了这些不利影响。根据我们的结果，LSS 介导的 EC 损伤可能与 STAT1 的激活有关。设计降低 STAT1 表达或抑制 STAT1 激活的策略可能是减少动脉粥样硬化发生率的有效方法。
