Activation of NF-κB/MAPK signaling and induction of apoptosis by salicylate synthase NbtS in promotes neuroinflammation development.

UNLABELLED

can cause a rare, yet potentially fatal, central nervous system infection. NbtS protein may be a key virulence factor in infection of the brain. In this study, we investigated the function of the virulence-associated factor NbtS in microglial cells and in infected mice . We explored the interactions between NbtS and microglial cells (BV2 and human microglial clone 3), revealing that NbtS activates the toll-like receptor 4-dependent MyD88-IRAK4-IRAK1 and MAPK/nuclear factor kappa B (NF-κB) pathways, significantly enhancing pro-inflammatory responses as indicated by increased levels of tumor necrosis factor alpha (TNF-α) and interleukin-1β (IL-1β), as measured by ELISA and quantitative PCR. Apoptosis was elevated in these cells, as shown by increased expression of Bax and caspase-3 and decreased Bcl-2 levels. The terminal deoxynucleotidyl transferase dUTP nick end labeling assay also confirmed the occurrence of apoptosis. In vivo, mice infected with an -deficient strain of exhibited higher survival rates and reduced brain inflammation, suggesting a pivotal role for the NbtS protein in the pathogenesis of . Conservation of the gene across spp. was verified by PCR, and the immunogenic potential of NbtS was confirmed by Western blot analysis using sera from infected mice. These findings suggest that targeting NbtS may offer a novel therapeutic strategy against infection.

IMPORTANCE

The study presented in this article delves into the molecular underpinnings of -induced neuroinflammation. By focusing on the salicylate synthase gene, , and its encoded protein, NbtS, we uncover a pivotal virulence factor that triggers a cascade of immunological responses leading to apoptosis in microglial cells. This research not only enhances our comprehension of the pathogenesis of infections but also provides a potential therapeutic target. Given the rising importance of understanding host-microbe interactions within the context of the central nervous system, especially in immunocompromised individuals, the findings are of significant relevance to the field of microbiology and could inform future diagnostic and treatment modalities for -associated neurological disorders. Our work emphasizes the need for continued research into the intricate mechanisms of microbial pathogenesis and the development of novel strategies to combat life-threatening infections.