Leptin signaling in the dorsomedial hypothalamus couples breathing and metabolism in obesity

SUMMARY Mismatch between CO2 production (VCO2) and respiration underlies the pathogenesis of obesity hypoventilation. Leptin-mediated CNS pathways stimulate both metabolism and breathing, but interactions between these functions remain elusive. We hypothesized that LEPRb+ neurons of the dorsomedial hypothalamus (DMH) regulate metabolism and breathing in obesity. In diet-induced obese LeprbCre mice, chemogenetic activation of LEPRb+ DMH neurons increases minute ventilation (VE) during sleep, the hypercapnic ventilatory response, VCO2, and VE/VCO2, indicating that breathing is stimulated out of proportion to metabolism. The effects of chemogenetic activation are abolished by a serotonin blocker. Optogenetic stimulation of the LEPRb+ DMH neurons evokes excitatory postsynaptic currents in downstream serotonergic neurons of the dorsal raphe (DR). Administration of retrograde AAV harboring Cre-dependent caspase to the DR deletes LEPRb+ DMH neurons and abolishes metabolic and respiratory responses to leptin. These findings indicate that LEPRb+ DMH neurons match breathing to metabolism through serotonergic pathways to prevent obesity-induced hypoventilation.


Figure S3 :
Figure S3: Activation of LEPR b neurons in the dorsomedial hypothalamus (DMH) did not affect body weight, food intake and body temperature.Body weight (A), food intake (B) and body temperature (C).

Figure S4 :
Figure S4: Ventilation during sleep in mice during activation of LEPR b neurons in the dorsomedial hypothalamus (DMH).Respiratory rate (RR) and tidal volume (VT) during REM sleep (Ai and Aii) in diet-induced obese Lepr b -Cre-GFP mice transfected with DREADD virus to the DMH (n = 16 -17).* p ≤ 0.05, using Wilcoxon matched-pairs signed rank.

Figure S5 :
Figure S5: Activation of LEPR b neurons in the dorsomedial hypothalamus (DMH) reduced apnea index and oxyhemoglobin desaturation index (ODI).Apnea frequency during NREM sleep (A) and total sleep (B).ODI was defined as a number of oxyhemoglobin desaturations ≥4% from baseline per hour of NREM sleep (C) and total sleep (D).* p ≤ 0.05, using Wilcoxon matched-pairs signed rank.

Figure S6 :
Figure S6: The lack of correlation between percentage of % of LEPR b + mCherry+ cells and minute veltination (V E ) in NREM sleep.Pearson correlation test was used for statistical comparisons.

Figure S7 :
Figure S7: Ventilation during sleep in mice treated with the control virus.Minute ventilation (VE) during NREM sleep (left, A).Maximal inspiratory flow (Vimax, center, B) and VE during REM sleep (right, C) in diet-induced obese Lepr b -Cre mice transfected with Control (n = 7 -8) virus.

Table S1 :
Sleep architecture and flow limited breaths of diet-induced obese Lepr b -Cre mice transfected with Control or floxed DREADD virus to the DMH.

Table S2 :
Sleep architecture of diet-induced obese Lepr b -Cre mice transfected with DREADD into the DMH plus retrograde Credependent AAV harboring caspase to the dorsal raphe nucleus