Nicotine instigates podocyte injury via NLRP3 inflammasomes activation.

Background/Aims: Recent studies have shown that nicotine induces podocyte damage. However, it remains unknown how nicotine induces podocyte injury. The present study tested whether nicotine induces NLRP3 inflammasomes activation and thereby contributes to podocyte injury. Results: Nicotine treatment significantly increased the colocalization of NLRP3 with Asc, caspase-1 activity, IL-beta production, cell permeability in podocytes compared to control cells. Pretreatment with caspase-1 inhibitor, WEHD significantly abolished the nicotine-induced colocalization of NLRP3 with Asc, caspase-1 activity, IL-1 beta production and cell permeability in podocytes. Immunofluorescence analysis showed that nicotine treatment significantly decreased the podocin and nephrin expression compared to control cells. However, prior treatment with WEHD attenuated the nicotine-induced podocin and nephrin reduction. In addition, we found that nicotine treatment significantly increased the O-2(center dot-) production compared to control cells. However, prior treatment with WEHD did not alter the nicotine-induced O-2(center dot-) production. Furthermore, prior treatment with ROS scavenger, NAC significantly attenuated the nicotine-induced caspase-1 activity, IL-1 beta production, podocin and nephrin reduction in podocytes. Conclusions: Nicotine-induced the NLRP3 inflammasome activation in podocytes and thereby results in podocyte injury. Methods: Inflammasome formation and immunofluorescence expressions were quantified by confocal microscopy. Caspase-1 activity, IL-1 beta production and O(2)(center dot-)production were measured by ELISA and ESR.