Chlamydia evasion of neutrophil host defense results in macrophage-associated sterile inflammation through the purinergic P2X7 receptor

Chlamydia trachomatis infection causes severe inflammatory disease resulting in blindness and infertility. The pathophysiology of these diseases remains elusive but myeloid cell-associated inflammation have been implicated. We show NLPR3 inflammasome activation is essential for driving a macrophage-associated endometritis resulting in infertility by using a female mouse genital tract chlamydial infection model. We found the chlamydial parasitophorous vacuole protein CT135 triggered NLRP3 inflammasome activation via TLR2/MyD88 signaling as a pathogenic strategy to evade neutrophil host defense. Paradoxically, a consequence of CT135 mediated neutrophil killing resulted in a submucosal macrophage-associated endometritis driven by ATP/P2X7R induced NLRP3 inflammasome activation. Importantly, macrophage-associated immunopathology occurred independent of macrophage infection. We show chlamydial infection of neutrophils and epithelial cells produce elevated levels of extracellular ATP. We propose this source of ATP serves as a DAMP to activate submucosal macrophage NLRP3 inflammasome that drive damaging immunopathology. These findings offer a novel paradigm of sterile inflammation in infectious disease pathogenesis.