The Mycobacterium tuberculosis ESX effector promotes pyroptosis-dependent pathogenicity and dissemination

Abstract

O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=126 SRC="FIGDIR/small/653593v1_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@8cd5e5org.highwire.dtl.DTLVardef@2ec22forg.highwire.dtl.DTLVardef@1ceb773org.highwire.dtl.DTLVardef@6dfba4_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphic AbstractC_FLOATNO C_FIG Mycobacterium tuberculosis (Mtb) remains a major global health threat, partly due to the extensive cytotoxicity induced during infection. Although GSDMD-mediated excessive pyroptosis promotes pathogen dissemination and tissue damage in tuberculosis, the mechanism remains poorly understood. Here, we identify the effector EccB5, a component of the Mtb ESX-5 secretion system, as a key driver of pyroptosis and hyperinflammatory responses. EccB5 enhances Mtb virulence by inducing pyroptosis of macrophages, promoting bacterial dissemination and exacerbating lung pathology. Conditional knockdown EccB5 increases host cell viability. Mechanistically, EccB5 directly interacts with GSDMD, strengthens its association with caspase-1, and facilitates caspase-1-mediated cleavage of GSDMD both in vitro and in vivo. In summary, our findings uncover a precise mechanism by which Mtb modulates host responses and advances its pathogenicity.