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.
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
This file is in Adobe Acrobat (PDF) format. If you have not installed and configured the Adobe Acrobat Reader on your system.
PDFs are designed to be printed out and read, but if you prefer to read them online, you may find it easier if you increase the view size to 125%.
Many versions of the free Acrobat Reader do not allow Save. You must instead save the PDF from the JCI Online page you downloaded it from. PC users: Right-click on the Download link and choose the option that says something like "Save Link As...". Mac users should hold the mouse button down on the link to get these same options.