Gonorrhea is a type III legal
communicable disease caused by Neisseria gonorrhoeae (NG), one of the most common sexually transmitted bacteria worldwide. NG
infection can cause
urethritis or systemic
inflammation and may lead to
infertility or other complications. The
NACHT, LRR, and PYD domains-containing protein 3 (NLRP3)
inflammasome is a
protein complex composed of NLRP3, apoptosis-associated speck-like
protein and caspase-1 and is an important part of the cellular machinery controlling the release of
interleukin (IL)-1β and
IL-18 and the pathogenesis of numerous
infectious diseases. It has been reported that NG
infection activates the NLRP3
inflammasome; however, the underlying mechanism remain unclear. In this report, the signaling pathways involved in the regulation of NG-mediated NLRP3
inflammasome activation in macrophages were studied. The results indicated that viable NG, but not heat-killed or freeze/thaw-killed NG, activated the NLRP3
inflammasome in macrophages through
toll-like receptor 2, but not
toll-like receptor 4. NG
infection provided the priming signal to the NLRP3
inflammasome that induced the expression of NLRP3 and IL-1β precursor through the
nuclear factor kappa B and
mitogen-activated protein kinase pathways. In addition, NG
infection provided the activation signal to the NLRP3
inflammasome that activated caspase-1 through
P2X7 receptor-dependent
potassium efflux, lysosomal acidification,
mitochondrial dysfunction, and
reactive oxygen species production pathways. Furthermore, we demonstrated that NLRP3 knockout increased phagocytosis of bacteria by macrophages and increases the bactericidal activity of macrophages against NG. These findings provide potential molecular targets for the development of anti-inflammatory drugs that could ameliorate NG-mediated
inflammation.