Cocaine use disorder is a major health crisis that is associated with increased oxidative stress and
neuroinflammation. While the role of NLRP3
inflammasome in mediating
neuroinflammation is well-recognized, whether
cocaine induces this response remains unexplored. Based on the premise that
cocaine induces both
reactive oxygen species (ROS) as well as microglial activation, we hypothesized that
cocaine-mediated microglial activation involves both ROS and NLRP3 signaling pathways. We examined activation of the NLRP3 pathway in microglia exposed to
cocaine, followed by validation in mice administered either
cocaine or saline for 7 days, with or without pretreatment with the NLRP3 inhibitor,
MCC950, and in postmortem cortical brain tissues of chronic
cocaine-dependent humans. We found that microglia exposed to
cocaine exhibited significant induction of NLRP3 and mature IL-1β expression. Intriguingly, blockade of ROS (
Tempol) attenuated
cocaine-mediated priming of NLRP3 and microglial activation (CD11b). Blockade of NLRP3 by both pharmacological (
MCC950) as well as gene silencing (siNLRP3) approaches underpinned the critical role of NLRP3 in
cocaine-mediated activation of
inflammasome and microglial activation. Pretreatment of mice with
MCC950 followed by
cocaine administration for 7 days mitigated
cocaine-mediated upregulation of mature IL-1β and CD11b, in both the striatum and the cortical regions. Furthermore, cortical brain tissues of chronic
cocaine-dependent humans also exhibited upregulated expression of the NLRP3 pathway mediators compared with non-
cocaine dependent controls. Collectively, these findings suggest that
cocaine activates microglia involving the NLRP3
inflammasome pathway, thereby contributing to
neuroinflammation. NLRP3 can thus be considered as a potential therapeutic target for alleviating
cocaine-mediated
neuroinflammation.