Regulation of adiponectin receptor 2 expression via PPAR-α in NIT-1 cells

Adiponectin receptors mediate the antidiabetic effects of adiponectin. Although suggested to be mainly expressed in muscle, liver, and adipocyte cells, the expression of adiponectin receptors in β cells is unclear. Given the primary involvement of this cell type in diabetes mellitus, we presently examined the expression level of adiponectin receptor 2 (AdiR2) in β cells. Expression was significantly increased under acute hyperlipidemic conditions but impaired under chronic conditions. The impaired AdiR2 expression may play a role in worsened β cell function. Clofibrate, an agonist of peroxisome proliferator-activated receptor-alpha (PPAR-α) delayed the palmitate-induced impairment of AdiR2 expression and PPAR-α; this delay was abolished by PPAR-α targeted small interfering RNA. The results suggest that AdiR2 expression is regulated by palmitate via PPAR-α.