Department of Cardiology, Zhongda Hospital, School of Medicine, Southeast University, 87 Dingjiaqiao, Nanjing, Jiangsu 210009, China.
Clin Sci (Lond). 2021 Feb 12;135(3):447-463. doi: 10.1042/CS20201235.
Abnormal vascular smooth muscle cell (VSMC) proliferation is a critical step in the development of atherosclerosis. Serpina3c is a serine protease inhibitor (serpin) that plays a key role in metabolic diseases. The present study aimed to investigate the role of serpina3c in atherosclerosis and regulation of VSMC proliferation and possible mechanisms. Serpina3c is down-regulated during high-fat diet (HFD)-induced atherosclerosis. An Apoe-/-/serpina3c-/--double-knockout mouse model was used to determine the role of serpina3c in atherosclerosis after HFD for 12 weeks. Compared with Apoe-/- mice, the Apoe-/-/serpina3c-/- mice developed more severe atherosclerosis, and the number of VSMCs and macrophages in aortic plaques was significantly increased. The present study revealed serpina3c as a novel thrombin inhibitor that suppressed thrombin activity. In circulating plasma, thrombin activity was high in the Apoe-/-/serpina3c-/- mice, compared with Apoe-/- mice. Immunofluorescence staining showed thrombin and serpina3c colocalization in the liver and aortic cusp. In addition, inhibition of thrombin by dabigatran in serpina3c-/- mice reduced neointima lesion formation due to partial carotid artery ligation. Moreover, an in vitro study confirmed that thrombin activity was also decreased by serpina3c protein, supernatant and cell lysate that overexpressed serpina3c. The results of experiments showed that serpina3c negatively regulated VSMC proliferation in culture. The possible mechanism may involve serpina3c inhibition of ERK1/2 and JNK signaling in thrombin/PAR-1 system-mediated VSMC proliferation. Our results highlight a protective role for serpina3c as a novel thrombin inhibitor in the development of atherosclerosis, with serpina3c conferring protection through the thrombin/PAR-1 system to negatively regulate VSMC proliferation through ERK1/2 and JNK signaling.
异常的血管平滑肌细胞（VSMC）增殖是动脉粥样硬化发展的关键步骤。Serpina3c 是一种丝氨酸蛋白酶抑制剂（丝氨酸蛋白酶抑制剂），在代谢性疾病中发挥关键作用。本研究旨在探讨 Serpina3c 在动脉粥样硬化中的作用以及对 VSMC 增殖的调节作用及其可能的机制。Serpina3c 在高脂肪饮食（HFD）诱导的动脉粥样硬化中下调。使用 Apoe-/-/serpina3c-/-双敲除小鼠模型来确定 HFD 12 周后 Serpina3c 在动脉粥样硬化中的作用。与 Apoe-/-小鼠相比，Apoe-/-/serpina3c-/-小鼠发生更严重的动脉粥样硬化，主动脉斑块中的 VSMC 和巨噬细胞数量明显增加。本研究揭示了 Serpina3c 作为一种新的凝血酶抑制剂，抑制凝血酶活性。在循环血浆中，Apoe-/-/serpina3c-/-小鼠的凝血酶活性高于 Apoe-/-小鼠。免疫荧光染色显示，肝脏和主动脉瓣中凝血酶和 Serpina3c 共定位。此外，在 Serpina3c-/-小鼠中，通过达比加群抑制凝血酶可减少由于颈动脉部分结扎引起的新生内膜损伤形成。此外，体外研究证实，Serpina3c 蛋白、上清液和过表达 Serpina3c 的细胞裂解物也降低了凝血酶活性。实验结果表明，Serpina3c 在培养物中负调控 VSMC 增殖。可能的机制可能涉及 Serpina3c 在凝血酶/PAR-1 系统介导的 VSMC 增殖中抑制 ERK1/2 和 JNK 信号通路。我们的研究结果强调了 Serpina3c 作为一种新的凝血酶抑制剂在动脉粥样硬化发展中的保护作用，Serpina3c 通过凝血酶/PAR-1 系统负调控 VSMC 增殖，通过 ERK1/2 和 JNK 信号通路发挥保护作用。
