NLRP3-inflammasome activation in male reproductive system diseases

The nucleotide-binding domain, leucine-rich containing family, pyrin domain-containing-3 (NLRP3) inflammasome, a multiprotein complex belonging to the innate immune system, plays a key role in the chronic inflammatory response through the production of pro-inflammatory cytokines, IL-1β and IL-18, which can elicit their effects through receptor activation, both locally and systemically. Furthermore, it has been demonstrated the interaction of NLRP3 inflammasome components with redox signaling, endoplasmic reticulum stress, and mitochondrial function. A growing literature reported the involvement of NLRP3 platform dysregulation in the pathophysiology of different chronic diseases so it has been proposed that the inhibition of NLRP3 inflammasome could represent a new potential therapeutic target in the management of autoimmune and chronic inflammatory diseases, including cancer. In addition, it has been demonstrated that SARS-CoV-2 preferentially activates NLRP3 inflammasome, strongly contributing to the hyperinflammatory state responsible for COVID-19. Recently, in-vitro and animal models of both infectious and non-infectious male genital tract diseases affecting fertility, demonstrated the activation of the innate immune system, leading to increased levels of pro-inflammatory cytokines, as well as apoptosis and pyroptosis and that it was likely mediated by activation of the NLRP3 inflammasome. The objective of this review was to analyze the evidence on the role and the mechanisms by which NLRP3-inflammasome pathway activation may exert detrimental effects on the male reproductive system. Furthermore, although the literature data are still discordant, this review also highlighted the possible connection between SARS-CoV-2 infection/NLRP3 activation/oxidative stress and male infertility.