Transcriptomics data integration reveals Jak-STAT as a common pathway affected by pathogenic intracellular bacteria in natural reservoir hosts

Abstract

The study of the host-pathogen interface in natural reservoir hosts is essential to identify host-cell mechanisms affected by bacterial infection and persistence. Herein we used the Database for Annotation, Visualization and Integrated Discovery (DAVID) to integrate transcriptomics data and find common host-cell biological processes, molecular functions and pathways affected by pathogenic intracellular bacteria of the genera Anaplasma, Brucella and Mycobacterium during infection and persistence in two natural reservoir hosts, wild boar and sheep. The results showed that the upregulation of host innate immune pro-inflammatory genes and signaling pathways constitutes a general antibacterial mechanism in response to intracellular bacteria. Pathway focused analysis revealed a role for the Jak-STAT pathway during bacterial intracellular infection, a fact reported before in Mycobacterium infected cells but not during Brucella spp. and A. phagocytophilum infection. A clear activation of the Jak-STAT pathway was observed in A. phagocytophilum infected wild boar and sheep when compared to uninfected controls. Brucella spp. infection resulted in a balanced regulation of the Jak-STAT signaling and M. bovis infection of wild boar clearly produced a downregulation of some of the Jak-STAT effectors such as IL5 and TKY2. These results suggested that mycobacteria and brucellae induce host innate immune responses while manipulating adaptive immunity to circumvent host-cell defenses and establish infection. In contrast, A. phagocytophilum infection induces both innate and adaptive immunity, those suggesting that this pathogen uses other mechanisms to circumvent host-cell defenses by downregulating other adaptive immune genes and delaying the apoptotic death of neutrophils through activation of the Jak-STAT pathway among other mechanisms.