Abstract
Weight loss medications are emerging candidates for pharmacotherapy of sleep-disordered breathing (SDB). A melanocortin 4 receptor (MC4R) agonist, setmelanotide (Set), is used to treat obesity caused by abnormal melanocortin and leptin signaling. We hypothesized that Set can treat SDB in mice with diet-induced obesity. We performed a proof-of-concept randomized crossover trial of a single dose of Set versus vehicle and a 2-week daily Set versus vehicle trial, examined colocalization of Mc4r mRNAs with the markers of CO2-sensing neurons Phox2b and neuromedin B in the brainstem, and expressed Cre-dependent designer receptors exclusively activated by designer drugs (DREADDs) or caspase in obese Mc4r-Cre mice. Set increased minute ventilation across sleep/wake states, enhanced the hypercapnic ventilatory response (HCVR), and abolished apneas during sleep. Phox2b+ neurons in the nucleus of the solitary tract (NTS) and the parafacial region expressed Mc4r. Chemogenetic stimulation of the MC4R+ neurons in the parafacial region, but not in the NTS, augmented HCVR without any changes in metabolism. Caspase elimination of the parafacial MC4R+ neurons abolished effects of Set on HCVR. Parafacial MC4R+ neurons projected to the respiratory premotor neurons retrogradely labeled from C3–C4. In conclusion, MC4R agonists enhance the HCVR and treat SDB by acting on the parafacial MC4R+ neurons.
Authors
Mateus R. Amorim, Noah R. Williams, O. Aung, Melanie Alexis Ruiz, Frederick Anokye-Danso, Junia L. de Deus, Jiali Xiong, Olga Dergacheva, Shannon Bevans-Fonti, Sean M. Lee, Jeffrey S. Berger, Mark N. Wu, Rexford S. Ahima, David Mendelowitz, Vsevolod Y. Polotsky
Figure 2
A single dose of Set increases total oxygen consumption (VO2) and carbon dioxide production (VCO2) compared with Veh, but
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ISSN: 0021-9738 (print), 1558-8238 (online)