Cadmium (Cd) has been reported to induce kidney damage by triggering oxidative stress and
inflammation. The NLR family Pyrin Domain Containing 3 (NLRP3)
inflammasome has been implicated a role in the pathogenesis of
inflammation. However, the connection between Cd and NLRP3
inflammasome in the development of renal
inflammation remains unknown. In this study, in vitro experiments based on the
telomerase-immortalized human renal proximal-tubule epithelial cell line (RPTEC/TERT1) were carried out. Results revealed that
CdCl2 (2-8 μM) increased ROS production and activated NLRP3, thereby enhancing secretion of IL-1β and
IL-18 (P < 0.05). Knock-down of NLRP3 rescued the RPTEC/TERT1 cells from Cd-induced inflammatory damage. Cd activated the MAPK/NF-κB signaling pathway in RPTEC/TERT1 cells (P < 0.05). In addition, treatment with
N-acetylcysteine (NAC) improved
inflammation and blocked the upregulation of the MAPK/NF-κB signaling pathway. Pre-treatment with MAPK and NF-κB inhibitors also suppressed NLRP3
inflammasome activation (P < 0.05). Moreover,
CdCl2 (25-00 mg/L) stimulated the MAPK/NF-κB signaling pathway, activated the NLRP3
inflammasome, and increased inflammatory response (P < 0.05) leading to renal injury in rats. Exposure to
cadmium elevated serum levels of NLRP3 and IL-1β in populations (P < 0.05). Further analysis found that serum NLRP3 and IL-1β levels were positively correlated with urine
cadmium (UCd) and urine N-acetyl-β-D-
glucosaminidase (UNAG). Overall, Cd induced renal
inflammation through the ROS/MAPK/NF-κB signaling pathway by activating the NLRP3
inflammasome. Our research thus provides new insights into the molecular mechanism that NLRP3 contributes to Cd-induced kidney damage.