Zhang Chengcheng, Hu Jiashu, Wang Xiuling, Wang Yuyang, Guo Mengjiao, Zhang Xiaorong, Wu Yantao
College of Veterinary Medicine, Yangzhou University, Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, Jiangsu, 225009, PR China.
College of Veterinary Medicine, Yangzhou University, Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, Jiangsu, 225009, PR China.
Virus Res. 2021 May;297:198346. doi: 10.1016/j.virusres.2021.198346. Epub 2021 Mar 16.
Avian reovirus (ARV) infection induced apoptosis in vitro and vivo; nevertheless, the intracellular molecular mechanisms have not been sufficiently revealed. In the previous studies, there have been shown that cellular apoptosis caused by ARV were related with GRP78/IRE1/XBP1 pathway. Protein kinase RNA-like endoplasmic reticulum kinase (PERK), inositol-requiring enzyme 1 (IRE1) and activating transcription factor 6 (ATF6) are core molecules in unfold protein response (UPR) and play critical role in ER stress related apoptosis, as well as downstream regulation factors, as Caspase-12 and C/EBP homologous protein (CHOP). In this study, we investigated with a focus on the contribution of UPR related signal pathways in the mechanism of ARV mediated apoptosis. Our results showed that the key molecules of UPR pathways proteins, ATF6, PERK and IRE1 as well as Caspase-12 and cleaved-Caspase-3 expression significant increased both in transcript and protein level in ARV infected cultured Vero cells. In the same time, the ARV induces apoptosis was observed by flow cytometric analysis. Further study revealed that when inhibit the UPR effect by 4PBA pretreated or knockdown of ATF6 by lentivirus mediated shRNA abolished the activation effect of UPR, Caspase-12, cleaved-Caspase-3 activation, as well as the apoptosis induction by ARV infection. The present study provides mechanistic insights into that UPR particular ATF6 played critical roles and works upstream of caspase in the process of cellular apoptosis induced by ARV infection.
禽呼肠孤病毒（ARV）感染在体外和体内均可诱导细胞凋亡；然而，其细胞内分子机制尚未得到充分揭示。在先前的研究中，已表明ARV引起的细胞凋亡与GRP78/IRE1/XBP1途径有关。蛋白激酶RNA样内质网激酶（PERK）、肌醇需求酶1（IRE1）和活化转录因子6（ATF6）是未折叠蛋白反应（UPR）中的核心分子，在与内质网应激相关的细胞凋亡以及下游调节因子（如半胱天冬酶-12和C/EBP同源蛋白（CHOP））中发挥关键作用。在本研究中，我们重点研究了UPR相关信号通路在ARV介导的细胞凋亡机制中的作用。我们的结果表明，在ARV感染的培养Vero细胞中，UPR通路蛋白的关键分子ATF6、PERK和IRE1以及半胱天冬酶-12和裂解的半胱天冬酶-3的表达在转录水平和蛋白水平均显著增加。同时，通过流式细胞术分析观察到ARV诱导的细胞凋亡。进一步的研究表明，当用4-苯基丁酸（4PBA）预处理抑制UPR效应或通过慢病毒介导的短发夹RNA（shRNA）敲低ATF6时，可消除UPR的激活效应、半胱天冬酶-12、裂解的半胱天冬酶-3的激活以及ARV感染诱导的细胞凋亡。本研究为UPR特别是ATF6在ARV感染诱导的细胞凋亡过程中发挥关键作用且在半胱天冬酶上游起作用提供了机制性见解。
