Pei Xiaomeng, Liu Junchi, Liu Mingxing, Zhou Hong, Wang Xiaomin, Fan Hongjie
MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.
Department of Microbiology, Zunyi Medical University, No.6 West Xuefu Road, Xinpu District, Zunyi, China.
AMB Express. 2020 Oct 30;10(1):195. doi: 10.1186/s13568-020-01131-2.
Streptococcus suis serotype 2 (SS2) is a serious zoonotic pathogen; it can lead to symptoms of streptococcal toxic shock syndrome (STSS) in humans and sepsis in pigs, and poses a great threat to public health. The SS2 MetQ gene deletion strain has attenuated antiphagocytosis, although the mechanism of antiphagocytosis and pathogenesis of MetQ in SS2 has remained unclear. In this study, stable isotope labeling by amino acids in cell culture (SILAC) based liquid chromatography-mass spectrometry (LC-MS) and subsequent bioinformatics analysis was used to determine differentially expressed proteins of RAW264.7 cells infected with △MetQ and ZY05719. Proteomic results were verified by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting for selected proteins. Further research was focused mainly on immune system processes related to downregulated proteins, such as Src and Ccl9, and actin cytoskeleton and endocytosis related upregulated proteins, like Pstpip1 and Ppp1r9b. The proteomic results in this study shed light on the mechanism of antiphagocytosis and innate immunity of macrophages infected with △MetQ and ZY05719, which might provide novel targets to prevent or control the infection of SS2.
猪链球菌2型（SS2）是一种严重的人畜共患病原体；它可导致人类出现链球菌中毒性休克综合征（STSS）症状以及猪出现败血症，对公共卫生构成巨大威胁。SS2的MetQ基因缺失菌株的抗吞噬作用减弱，尽管MetQ在SS2中的抗吞噬作用和致病机制尚不清楚。在本研究中，基于细胞培养中氨基酸的稳定同位素标记（SILAC）的液相色谱-质谱联用（LC-MS）及随后的生物信息学分析，用于确定感染△MetQ和ZY05719的RAW264.7细胞的差异表达蛋白。通过定量实时聚合酶链反应（qRT-PCR）和对选定蛋白的蛋白质免疫印迹法验证蛋白质组学结果。进一步的研究主要集中在与下调蛋白（如Src和Ccl9）相关的免疫系统过程，以及与肌动蛋白细胞骨架和内吞作用相关的上调蛋白（如Pstpip1和Ppp1r9b）。本研究中的蛋白质组学结果揭示了感染△MetQ和ZY05719的巨噬细胞的抗吞噬作用和先天免疫机制，这可能为预防或控制SS2感染提供新的靶点。
