Abstract
The nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP-3) inflammasome has recently emerged as a pivotal regulator of chronic inflammation. The present study investigated the expression of NLRP3 inflammasome in phorbol 12-myristate 13-acetate (PMA)-induced macrophages, and aimed to identify the effects of berberine on the inflammasome. Human monocytic THP-1 cells were pretreated with berberine for 1 h and then induced with PMA for 48 h. Total RNA and protein were collected for reverse transcription-quantitative polymerase chain reaction and western blot analysis, respectively. Supernatants were collected to determine IL-1β levels by using ELISA. The present study demonstrated that NLRP3 inflammasome and IL-1β were activated in PMA-induced macrophages in a time-dependent manner, whereas berberine significantly inhibited their expression in a dose-dependent manner in PMA-induced macrophages. Furthermore, berberine also suppressed the toll-like receptor 4 (TLR4)/myeloid differentiation primary response gene 88 (Myd88)/nuclear factor (NF)-κB signaling pathway which was activated during the conversion of THP-1 cells to macrophages by PMA. In conclusion, berberine reduced NLRP3 inflammasone expression by suppressing the activation of the TLR4/Myd88/NF-κB signaling pathway in PMA-induced macrophages. This inhibitory effect may imply an important role of berberine on chronic inflammation and atherogenic progression in coronary artery disease.