Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian 271000, China; Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, Taian 271000, China, China.
Analytic Laboratory, Institute of Preclinical Medicine, Taishan Medical University, Taian 271000, China.
Vet Microbiol. 2018 Jan;213:5-14. doi: 10.1016/j.vetmic.2017.11.003. Epub 2017 Nov 6.
H9N2 subtype low pathogenic avian influenza virus (LPAIV) is distributed worldwide and causes great economic losses in the poultry industry, especially when complicated with other bacterial infections. Tissue damages caused by virus infection provide an opportunity for bacteria invasion, but this mechanism is not sufficient for low pathogenic strains. Moreover, although H9N2 virus infection was demonstrated to promote bacterial infection in several studies, its mechanism remained unclear. In this study, infection experiments in vivo and in vitro demonstrated that the adhesion of Escherichia coli (E. coli) to host cells significantly increased after H9N2 virus infection, and this increase was not caused by pathological damages. Subsequently, we constructed a late chicken embryo infection model and used proteomics techniques to analyze the expression of proteins associated with bacterial adhesion after H9N2 virus infection. A total of 279 significantly differential expressed proteins were detected through isobaric tags for relative and absolute quantitation (iTRAQ) coupled with nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) analysis. The results of Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis showed that differentially expressed proteins were enriched in host innate immunity; cell proliferation, differentiation, and apoptosis; and pathogenicity-related signaling pathways. Finally, we screened out several proteins, such as TGF-β1, integrins, cortactin, E-cadherin, vinculin, and fibromodulin, which were probably associated with bacterial adhesion. The study analyzed the mechanism of secondary bacterial infection induced by H9N2 virus infection from a novel perspective, which provided theoretical and data support for investigating the synergistic infection mechanism between the H9N2 virus and bacteria.
H9N2 亚型低致病性禽流感病毒（LPAIV）分布广泛，给家禽业造成了巨大的经济损失，尤其是当与其他细菌感染合并时。病毒感染引起的组织损伤为细菌入侵提供了机会，但这一机制对于低致病性株并不充分。此外，尽管有几项研究表明 H9N2 病毒感染会促进细菌感染，但其机制仍不清楚。在本研究中，体内和体外感染实验表明，H9N2 病毒感染后大肠杆菌（E. coli）与宿主细胞的黏附显著增加，而这种增加不是由病理损伤引起的。随后，我们构建了晚期鸡胚感染模型，并使用蛋白质组学技术分析了 H9N2 病毒感染后与细菌黏附相关的蛋白质表达。通过相对和绝对定量同位素标记（iTRAQ）与纳升液相色谱-串联质谱（nano-LC-MS/MS）分析共检测到 279 个差异表达蛋白。京都基因与基因组百科全书（KEGG）富集分析的结果表明，差异表达蛋白富集于宿主固有免疫、细胞增殖、分化和凋亡以及与致病性相关的信号通路。最后，我们筛选出了几个可能与细菌黏附相关的蛋白，如 TGF-β1、整合素、桩蛋白、E-钙黏蛋白、纽蛋白和纤维蛋白。该研究从新的角度分析了 H9N2 病毒感染引起继发细菌感染的机制，为研究 H9N2 病毒与细菌的协同感染机制提供了理论和数据支持。
