Benidipine Hydrochloride Inhibits NLRP3 Inflammasome Activation by Inhibiting LPS-Induced NF-κB Signaling in THP-1 Macrophages.

Introduction: NLRP3, ASC, and procaspase-1 form the multiprotein complex known as the NLRP3 inflammasome. Following the priming of NLRP3 by TLR4 ligand, the activation of the NLRP3 inflammasome causes caspase-1 maturation, which results in the release of IL-1β. Calcium channel antagonists are commonly employed as antihypertensive medications and have anti-inflammatory properties through the inhibition of cytokine release, specifically IL-1β. The impact of calcium channel antagonists on NLRP3 inflammasomes, however, has not been well studied. This study aimed to investigate the effect of the calcium channel blocker benidipine hydrochloride on LPS-induced NLRP3 inflammasome activation in THP-1 macrophages and its possible mechanism.

Methods: Firstly, the cytotoxicity of benidipine hydrochloride was determined by MTT. The effect of benidipine hydrochloride on LPS-induced IL-1β release was determined by ELISA. Then, the effect of benidipine hydrochloride on the expression of IL-1β, NLRP3, ASC, and Caspase-1 induced by LPS was determined by QPCR, and the expression of IL-1β, GSDMD, Caspase-1, and their active forms was determined by Western blot, and the activation of NF-κB was determined by Western blot and immunofluorescence. Finally, the production of ROS was determined by flow cytometry and fluorescence microscopy.

Results: Benidipine hydrochloride was found to drastically lower the expression of NLRP3, ASC, and caspase 1, which in turn decreased the amount of IL-1β secreted by THP-1 macrophages. Benidipine hydrochloride dramatically reduced the phosphorylation level of NF-κB p65 and its nuclear translocation in THP-1 macrophages. Furthermore, benidipine hydrochloride significantly decreased the generation of ROS.

Discussion: Based on these results, we deduced that benidipine hydrochloride prevents ROS formation in THP-1 macrophages and LPS-induced NF-κB signaling, which in turn prevents the activation of NLRP3 inflammasomes and the release of IL-1β.