Zhang Jing, Liu Fei, He Yu-Bin, Zhang Wei, Ma Wen-Rui, Xing Jie, Wang Li-Xin
Department of Cardiovascular Surgery, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China.
Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
Front Physiol. 2020 Sep 24;11:548055. doi: 10.3389/fphys.2020.548055. eCollection 2020.
Polycystin-1 (PC-1) is a protein encoded by the gene of polycystic kidney disease-1 (PKD-1). This study was designed to investigate the regulatory mechanisms of PC-1 on phenotypes of aortic vascular smooth muscle cells (VSMCs) and functions of extracellular matrix (ECM) in thoracic aortic dissection (TAD).
Aortic tissues from patients with TAD and healthy controls were collected, primary aortic VSMCs were also isolated. Immunohistochemistry, immunofluorescence, and immunocytochemistry was used to visualize the target proteins. Western blot and RT-qPCR were used to examine the expression of mRNA and proteins. Lentivirus infection was used to downregulate or overexpress PC-1.
Compared with the control group, expression of PC-1 and the contractile phenotypic markers of VSMCs were decreased in TAD group, whereas expression of the synthetic markers of VSMCs, matrix metalloproteinase (MMP)-2, collagen I and collagen III were increased. The phosphorylation of mTOR, S6K and S6 were also elevated in TAD group. PC-1 downregulation of aortic VSMCs inhibited the expression of the contractile markers, but elevated the expression of the synthetic markers, MMP-2, collagen I and collagen III compared with the control group. The phosphorylation of mTOR, S6K and S6 were also increased in PKD-1-knockdown VSMCs. PC-1 upregulation reversed all these expression characteristics in aortic VSMCs. Furthermore, rapamycin treatment to PKD-1-knockdown VSMCs inhibited the effects caused by PC-1 downregulation.
Our study revealed PC-1 downregulation induces aortic VSMCs phenotypic alteration and ECM remodeling via activation of mTOR/S6K/S6 signaling pathway. Downregulation of PC-1 might be a potential mechanism for the development and progression of TAD. Rapamycin might be a potential inhibitor to attenuate the development and progression of TAD.
多囊蛋白-1（PC-1）是由多囊肾病-1（PKD-1）基因编码的一种蛋白质。本研究旨在探讨PC-1对胸主动脉夹层（TAD）中主动脉血管平滑肌细胞（VSMCs）表型及细胞外基质（ECM）功能的调控机制。
收集TAD患者及健康对照者的主动脉组织，同时分离原代主动脉VSMCs。采用免疫组织化学、免疫荧光和免疫细胞化学方法观察目标蛋白。运用蛋白质免疫印迹法（Western blot）和逆转录定量聚合酶链反应（RT-qPCR）检测mRNA和蛋白质表达。通过慢病毒感染下调或上调PC-1。
与对照组相比，TAD组PC-1及VSMCs收缩表型标志物的表达降低，而VSMCs合成标志物、基质金属蛋白酶（MMP）-2、Ⅰ型胶原和Ⅲ型胶原的表达增加。TAD组中雷帕霉素靶蛋白（mTOR）、核糖体蛋白S6激酶（S6K）和核糖体蛋白S6（S6）的磷酸化水平也升高。与对照组相比，下调主动脉VSMCs的PC-1可抑制收缩标志物的表达，但增加合成标志物、MMP-2、Ⅰ型胶原和Ⅲ型胶原的表达。PKD-1基因敲低的VSMCs中mTOR、S6K和S6的磷酸化水平也升高。上调PC-1可逆转主动脉VSMCs的所有这些表达特征。此外，对PKD-1基因敲低的VSMCs进行雷帕霉素处理可抑制PC-1下调所引起的效应。
我们的研究表明，PC-1下调通过激活mTOR/S6K/S6信号通路诱导主动脉VSMCs表型改变和ECM重塑。PC-1下调可能是TAD发生发展的潜在机制。雷帕霉素可能是减轻TAD发生发展的潜在抑制剂。
