Liu Xiaoran, Cao Yanyan, Hu Xiucai, Lv Aijun
Tianjin Key Lab of Aqua-Ecology and Aquaculture, College of Fisheries, Tianjin Agricultural University, Tianjin, 300392, China.
Tianjin Key Lab of Aqua-Ecology and Aquaculture, College of Fisheries, Tianjin Agricultural University, Tianjin, 300392, China.
Fish Shellfish Immunol. 2025 Mar;158:110155. doi: 10.1016/j.fsi.2025.110155. Epub 2025 Jan 24.
Rahnella aquatilis is an emerging opportunistic pathogen that usually causes septicemia in fish and poses a potential threat to human health. VgrG gene is an important virulence factor of type VI secretion system in R. aquatilis, but its regulatory mechanism underlying PANoptosis is still unknown. Here, VgrG deletion mutant strain of R. aquatilis (ΔVgrG-RA) and recombinant plasmid pET32a-VgrG were respectively constructed, and immunohistochemistry for VgrG as well as PANoptosis features were evaluated. Moreover, the interaction transcriptome of ΔVgrG-mediated pathogen and host was determined by dual RNA-seq using an in vitro model of the primary macrophage cells from crucian carp Carassius auratus, and a total of 889 and 3765 differentially expressed genes (DEGs) were identified in pathogen-host interaction genes, respectively. Notably, GO and KEGG enrichment analysis were significantly involved in the PANoptosis pathways in ΔVgrG mutant-infected macrophages. The regulatory relationship of potential PANoptosis-related genes (PRGs) were analysed comprehensively, and their binding interaction of several hub proteins (eg., YcgR, Bcl2a, Calr3a, IL-1β) were determined by molecular docking analysis. To our best knowledge, this is first report of R. aquatilis VgrG-mediated interactions between pathogen and host macrophage cells, which will provide a new reference for understanding of molecular mechanism underlying PANoptosis in fish.
水生拉恩菌是一种新出现的机会致病菌，通常会导致鱼类败血症，并对人类健康构成潜在威胁。VgrG基因是水生拉恩菌VI型分泌系统的一个重要毒力因子，但其在PAN凋亡中的调控机制仍不清楚。在此，分别构建了水生拉恩菌VgrG缺失突变株（ΔVgrG-RA）和重组质粒pET32a-VgrG，并对VgrG进行了免疫组织化学以及PAN凋亡特征评估。此外，利用鲫鱼原代巨噬细胞的体外模型，通过双RNA测序确定了ΔVgrG介导的病原体与宿主的相互作用转录组，在病原体-宿主相互作用基因中分别鉴定出889个和3765个差异表达基因（DEG）。值得注意的是，GO和KEGG富集分析显著涉及ΔVgrG突变体感染巨噬细胞中的PAN凋亡途径。全面分析了潜在的PAN凋亡相关基因（PRG）的调控关系，并通过分子对接分析确定了几种枢纽蛋白（如YcgR、Bcl2a, Calr3a、IL-1β）的结合相互作用。据我们所知，这是关于水生拉恩菌VgrG介导的病原体与宿主巨噬细胞之间相互作用的首次报道，这将为理解鱼类PAN凋亡的分子机制提供新的参考。
