National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, VA 20110, USA.
Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
Viruses. 2021 May 12;13(5):892. doi: 10.3390/v13050892.
Venezuelan equine encephalitis virus (VEEV) is an alphavirus that causes encephalitis. Previous work indicated that VEEV infection induced early growth response 1 (EGR1) expression, leading to cell death via the protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK) arm of the unfolded protein response (UPR) pathway. Loss of PERK prevented EGR1 induction and decreased VEEV-induced death. The results presented within show that loss of PERK in human primary astrocytes dramatically reduced VEEV and eastern equine encephalitis virus (EEEV) infectious titers by 4-5 log. Loss of PERK also suppressed VEEV replication in primary human pericytes and human umbilical vein endothelial cells, but it had no impact on VEEV replication in transformed U87MG and 293T cells. A significant reduction in VEEV RNA levels was observed as early as 3 h post-infection, but viral entry assays indicated that the loss of PERK minimally impacted VEEV entry. In contrast, the loss of PERK resulted in a dramatic reduction in viral nonstructural protein translation and negative-strand viral RNA production. The loss of PERK also reduced the production of Rift Valley fever virus and Zika virus infectious titers. These data indicate that PERK is an essential factor for the translation of alphavirus nonstructural proteins and impacts multiple RNA viruses, making it an exciting target for antiviral development.
委内瑞拉马脑炎病毒（VEEV）是一种引起脑炎的甲病毒。先前的工作表明，VEEV 感染诱导早期生长反应 1（EGR1）表达，通过未折叠蛋白反应（UPR）途径中的蛋白激酶 R（PKR）样内质网激酶（PERK）臂导致细胞死亡。PERK 的缺失阻止了 EGR1 的诱导，并减少了 VEEV 诱导的死亡。本文中的结果表明，在人原代星形胶质细胞中缺失 PERK 可使 VEEV 和东部马脑炎病毒（EEEV）的感染滴度降低 4-5 个对数级。PERK 的缺失也抑制了原代人周细胞和人脐静脉内皮细胞中的 VEEV 复制，但对转化的 U87MG 和 293T 细胞中的 VEEV 复制没有影响。在感染后 3 小时即可观察到 VEEV RNA 水平的显著降低，但病毒进入实验表明 PERK 的缺失对 VEEV 进入的影响最小。相比之下，PERK 的缺失导致病毒非结构蛋白翻译和负链病毒 RNA 产生的显著减少。PERK 的缺失也降低了裂谷热病毒和寨卡病毒感染滴度。这些数据表明 PERK 是甲病毒非结构蛋白翻译的必需因素，并影响多种 RNA 病毒，使其成为抗病毒药物开发的一个令人兴奋的靶点。
