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; Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou, Jiangsu 225009, PR China; Jiangsu Research Centre of Engineering and Technology for Prevention and Control of Poultry Disease, 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; Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou, Jiangsu 225009, PR China; Jiangsu Research Centre of Engineering and Technology for Prevention and Control of Poultry Disease, Yangzhou, Jiangsu 225009, PR China.
Infect Genet Evol. 2021 Jan;87:104672. doi: 10.1016/j.meegid.2020.104672. Epub 2020 Dec 9.
H5N8 subtype highly pathogenic avian influenza viruses (HPAIVs) pose a huge threat to poultry industry and general public health. Our previous study demonstrated that synergistic effect of 283M and 526R in PB2 gene was a critical factor for viral high pathogenicity in mammals. However, the potential pathogenic mechanism of the mutant virus is still unclear. Here, RNA-seq method was used to analyze the global host response of murine lungs after infecting with parental r-JY virus and JY-PB2-I283M-K526R mutant virus. We found that both amounts and the expression levels of host differentially expressed genes (DEGs) were higher in mutant virus-infected mice compared with the group of parental virus. Furthermore, the DEGs mainly related with innate immune response by GO and KEGG analysis. Especially, PB2-I283M-K526R mutation strongly induced a sharp expression of cytokine storm-related genes, including MX1, CXCL10, and IFN-γ, performed by qRT-PCR. We also found that PB2-I283M-K526R mutation accelerated the level of cell apoptosis by heat map analysis of apoptosis-related DEGs in lungs and apoptosis assay in vitro. Taken together, our data demonstrated that PB2-I283M-K526R of H5N8 subtype HPAIV exacerbated the innate immune response and the level of cell apoptosis, which might be a key pathogenic mechanism for the enhanced pathogenicity of mutants in mammals.
H5N8 亚型高致病性禽流感病毒（HPAIVs）对家禽业和公众健康构成巨大威胁。我们之前的研究表明，PB2 基因中的 283M 和 526R 的协同作用是病毒在哺乳动物中高致病性的关键因素。然而，突变病毒的潜在致病机制仍不清楚。在这里，我们使用 RNA-seq 方法分析了感染亲本 r-JY 病毒和 JY-PB2-I283M-K526R 突变病毒后小鼠肺部的宿主全基因组反应。我们发现，与亲本病毒感染组相比，突变病毒感染组的宿主差异表达基因（DEGs）数量和表达水平更高。此外，通过 GO 和 KEGG 分析，DEGs 主要与先天免疫反应有关。特别是，PB2-I283M-K526R 突变强烈诱导细胞因子风暴相关基因（包括 MX1、CXCL10 和 IFN-γ）的急剧表达，通过 qRT-PCR 进行验证。我们还发现，PB2-I283M-K526R 突变通过肺部细胞凋亡相关 DEGs 的热图分析和体外细胞凋亡实验加速了细胞凋亡水平。综上所述，我们的数据表明，H5N8 亚型 HPAIV 的 PB2-I283M-K526R 增强了先天免疫反应和细胞凋亡水平，这可能是突变体在哺乳动物中增强致病性的关键致病机制。
