TRIM32 Drives Pathogenesis in Streptococcal Toxic Shock-Like Syndrome and Streptococcus suis Meningitis by Regulating Innate Immune Responses.

Streptococcus suis is an emerging zoonotic agent that causes streptococcal toxic shock-like syndrome (STSLS) and meningitis in humans, with high mortality and morbidity. The pathogenesis of both STSLS and central nervous system (CNS) infections caused by S. suis is not well understood. TRIM32, a member of the tripartite motif (TRIM) protein family, has been reported to regulate host inflammatory responses. In this study, we showed that TRIM32 deficiency significantly reduced the level of bacteremia and the production of proinflammatory cytokines following severe S. suis infection, protecting infected mice from STSLS. The influence of TRIM32 gene deletion on a range of processes known to be involved in S. suis meningitis was also examined. Both levels of bacterial loads and indications of brain hemorrhage were reduced in infected Trim32-/- mice compared with infected wild-type (WT) controls. We also found that TRIM32 deficiency increased the permeability of the blood-brain barrier (BBB) and the recruitment of inflammatory monocytes during the early course of S. suis infection, potentially limiting the development of S. suis meningitis. Our results suggest that TRIM32 sensitizes S. suis-induced infection via innate immune response regulation.