Functional coupling between MC4R and Kir7.1 contributes to clozapine-induced hyperphagia

Area of Science:

• Neuroscience
• Pharmacology
• Metabolic Research

Background:

• Antipsychotic drugs (APDs) commonly cause hyperphagia and weight gain, but underlying neural mechanisms remain unclear.
• Rodent models have struggled to fully replicate these metabolic effects, hindering research.
• Clozapine and risperidone are widely prescribed APDs known to induce significant weight gain.

Purpose of the Study:

• To establish a novel mouse model that accurately replicates clozapine-induced overeating.
• To elucidate the specific neural pathways and molecular interactions targeted by clozapine.
• To identify potential therapeutic targets for mitigating APD-associated metabolic side effects.

Main Methods:

• Development of a new mouse model for studying clozapine-induced hyperphagia.
• Investigation of clozapine's effects on melanocortin 4 receptor (MC4R) expressing neurons in the hypothalamus.
• Analysis of MC4R signaling pathways, including receptor-ligand binding and Gαs signaling.
• Assessment of the interaction between MC4R and Kir7.1 potassium channels.
• Genetic manipulation (Kir7.1 deletion) and pharmacological inhibition of Kir7.1.

Main Results:

• Clozapine administration significantly increased food intake in the novel mouse model.
• Clozapine inhibits MC4R-expressing neurons by enhancing MC4R-Kir7.1 coupling, independent of canonical Gαs signaling.
• Deletion of Kir7.1 in MC4R neurons abolished clozapine-induced weight gain.
• Pharmacological blockade of Kir7.1 reduced overeating in mice treated with clozapine.

Conclusions:

• A novel mouse model successfully recapitulates APD-induced hyperphagia.
• The MC4R-Kir7.1 pathway is a critical mediator of clozapine's effects on feeding behavior.
• Targeting the MC4R-Kir7.1 interaction presents a promising therapeutic strategy for managing APD-associated weight gain.