A neural basis for melanocortin-4 receptor-regulated appetite.

Pro-opiomelanocortin (POMC)- and agouti-related peptide (AgRP)-expressing neurons of the arcuate nucleus of the hypothalamus (ARC) are oppositely regulated by caloric depletion and coordinately stimulate and inhibit homeostatic satiety, respectively. This bimodality is principally underscored by the antagonistic actions of these ligands at downstream melanocortin-4 receptors (MC4R) in the paraventricular nucleus of the hypothalamus (PVH). Although this population is critical to energy balance, the underlying neural circuitry remains unknown. Using mice expressing Cre recombinase in MC4R neurons, we demonstrate bidirectional control of feeding following real-time activation and inhibition of PVH(MC4R) neurons and further identify these cells as a functional exponent of ARC(AgRP) neuron-driven hunger. Moreover, we reveal this function to be mediated by a PVH(MC4R)?lateral parabrachial nucleus (LPBN) pathway. Activation of this circuit encodes positive valence, but only in calorically depleted mice. Thus, the satiating and appetitive nature of PVH(MC4R)?LPBN neurons supports the principles of drive reduction and highlights this circuit as a promising target for antiobesity drug development. Overall design: Single-neuron mRNA-seq was performed on fluorescently-labeled or -unlabeled cells that were manually isolated from dissociated adult mouse paraventricular and arcuate hypothalamus: Mc4r-2a-Cre::L10-GFP+ or Mc4r-2a-Cre::AAV-XFP+ or Mc4r-2a-Cre::AAV-XFP-negative PVH neurons; Agrp-IRES-Cre::L10-GFP+ ARC neurons; Pomc-hrGFP+ ARC neurons; and vGLUT2-IRES-Cre::AAV-XFP+ ARC neurons Note: Raw files unavailable for samples GSM2413312 GSM2413313 GSM2413314 GSM2413346 GSM2413347

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Garfield AS, Li C, Madara JC, Shah BP, Webber E, Steger JS, Campbell JN, Gavrilova O, Lee CE, Olson DP, Elmquist JK, Tannous BA, Krashes MJ, Lowell BB