Rahnella aquatilis VgrG-mediated PANoptosis in macrophages of Carassius auratus by dual RNA-seq analysis

Abstract

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.