Asprosin promotes feeding through SK channel–dependent activation of AgRP neurons

Abstract

Asprosin, a recently identified adipokine, activates agouti-related peptide (AgRP) neurons in the arcuate nucleus of the hypothalamus (ARH) via binding to protein tyrosine phosphatase receptor δ (Ptprd) to increase food intake. However, the intracellular mechanisms responsible for asprosin/Ptprd-mediated activation of AgRP ARH neurons remain unknown. Here, we demonstrate that the small-conductance calcium-activated potassium (SK) channel is required for the stimulatory effects of asprosin/Ptprd on AgRP ARH neurons. Specifically, we found that deficiency or elevation of circulating asprosin increased or decreased the SK current in AgRP ARH neurons, respectively. AgRP ARH -specific deletion of SK3 (an SK channel subtype highly expressed in AgRP ARH neurons) blocked asprosin-induced AgRP ARH activation and overeating. Furthermore, pharmacological blockade, genetic knockdown, or knockout of Ptprd abolished asprosin’s effects on the SK current and AgRP ARH neuronal activity. Therefore, our results demonstrated an essential asprosin-Ptprd-SK3 mechanism in asprosin-induced AgRP ARH activation and hyperphagia, which is a potential therapeutic target for the treatment of obesity.