Adiponectin, an adipokine with insulin-sensitizing effect, is secreted from adipocytes into circulation as high, medium, and low molecular weight (HMW, MMW, and LMW) forms. The HMW adiponectin is more metabolically active and the ratio of HMW adiponectin to total adiponectin directly correlates with insulin sensitivity. Evodiamine is an indole alkaloid found in the traditional Chinese medicinal plant Evodia rutaecarpa. In this study, evodiamine was found to activate AMP-activated protein kinase (AMPK) in both 3T3-L1 adipocytes and 293T cells. Activation of AMPK by evodiamine promoted the assembly of HMW adiponectin and increased the HMW/total ratio of adiponectin in 3T3-L1 adipocytes. The Ca(2+)-dependent PI3K/Akt/CaMKII-signaling pathway was demonstrated to be involved in evodiamine-induced AMPK activation. This study revealed a novel role of this Ca(2+)-mediated signaling pathway in promoting the multimerization of adiponectin.
Keywords: AMPK; CaMKII; adiponectin; evodiamine; multimerization.