Zhang Yuxing, Zhang Xiliang, Cao Zhen, Huang Yun, Zheng Yuexin, Yang Xiaodong
Department of General Surgery, The Sixth Medical Center of PLA General Hospital, Beijing 100048, People's Republic of China.
Open Life Sci. 2021 Oct 21;16(1):1141-1150. doi: 10.1515/biol-2021-0114. eCollection 2021.
Vascular hyporesponsiveness in the shock decompensation period is an important factor leading to death. Myosin light chain 20 (MLC) is the main effector protein that regulates vascular reactivity. However, whether the change in semicarbazide-sensitive amine oxidase (SSAO) expression during hypoxia can change the MLC phosphorylation level, and its underlying mechanism were not clear. The amine oxidase copper containing 3 (AOC3) overexpressing adenovirus vector was constructed and transfected into rat intestinal microvascular endothelial cells (RIMECs) to overexpress SSAO, and the RIMECs were co-cultured with rat intestinal microvascular smooth muscle cells (RIMSCs). The changes in SSAO/inducible nitric oxide synthase (iNOS)/Rho associate coiled-coil containing protein kinase 1 (ROCK1) expression levels and MLC phosphorylation level were detected. Here we found that the increased SSAO by AOC3 overexpression can decrease the iNOS expression level and its activity after hypoxia. In addition, RIMSCs co-cultured with RIMECs overexpressed with AOC3 gene had significantly higher ROCK1 protein level and MLC phosphorylation level than RIMSCs co-cultured with normal RIMECs. Our study demonstrated that SSAO overexpression can significantly inhibit iNOS activity, promote RhoA/ROCK pathway activation, and increase the phosphorylation level of MLC, which might be the potential mechanism in relieving the vascular hyporesponsiveness during shock decompensation.
休克失代偿期的血管低反应性是导致死亡的重要因素。肌球蛋白轻链20（MLC）是调节血管反应性的主要效应蛋白。然而，缺氧期间氨基脲敏感胺氧化酶（SSAO）表达的变化是否会改变MLC磷酸化水平及其潜在机制尚不清楚。构建含胺氧化酶铜3（AOC3）过表达腺病毒载体并转染至大鼠肠微血管内皮细胞（RIMECs）以过表达SSAO，并将RIMECs与大鼠肠微血管平滑肌细胞（RIMSCs）共培养。检测SSAO/诱导型一氧化氮合酶（iNOS）/Rho相关卷曲螺旋蛋白激酶1（ROCK1）表达水平及MLC磷酸化水平的变化。在此我们发现，AOC3过表达导致的SSAO增加可降低缺氧后iNOS表达水平及其活性。此外，与过表达AOC3基因的RIMECs共培养的RIMSCs比与正常RIMECs共培养的RIMSCs具有显著更高的ROCK1蛋白水平和MLC磷酸化水平。我们的研究表明，SSAO过表达可显著抑制iNOS活性，促进RhoA/ROCK途径激活，并增加MLC磷酸化水平，这可能是缓解休克失代偿期血管低反应性的潜在机制。
