Functional coupling between MC4R and Kir7.1 contributes to clozapine-induced weight gain in female mice.

Abstract

Most antipsychotic drugs (APDs) cause hyperphagia and weight gain, yet the neural mechanisms underlying these metabolic side effects remain elusive, in part due to difficulties in modeling them in rodents. Here, we establish a mouse model that recapitulates clozapine-induced metabolic syndrome, enabling mechanistic investigation of this widely prescribed APD. We show that clozapine promotes obesity in female mice by driving hyperphagia, which requires functional coupling between the melanocortin 4 receptor (MC4R) and the Kir7.1 potassium channel. Within the broader context of clozapine's polypharmacology, this signaling axis emerges as a critical downstream convergence node for APD-induced metabolic dysfunction. Mechanistically, clozapine inhibits MC4R-expressing neurons in the paraventricular nucleus of the hypothalamus by enhancing MC4R-Kir7.1 coupling, thereby increasing inward potassium currents. Notably, clozapine produces this inhibition without binding the MC4R orthosteric site and without engaging canonical Gαs signaling. Genetic deletion of Kir7.1 in MC4R neurons or pharmacological inhibition of Kir7.1 reverses clozapine-induced weight gain while preserving its behavioral efficacy in established antipsychotic assays. Together, these findings reveal a G-protein-independent mechanism by which clozapine disrupts energy balance and identify MC4R-Kir7.1 coupling as a therapeutically tractable pathway for mitigating APD-associated metabolic dysfunction.