Dopamine-inhibited POMCDrd2+ neurons in the ARC acutely regulate feeding and body temperature

Dopamine acts on neurons in the arcuate nucleus of the hypothalamus (ARC) which control homeostatic feeding responses. Here we demonstrate a differential enrichment of Drd1 expression in food intake-promoting AgRP/NPY neurons and a large proportion of Drd2-expressing anorexigenic POMC neurons. This translates into a predominant activation of AgRP/NPY neurons upon dopamine stimulation and a larger proportion of dopamine-inhibited POMC neurons. Employing intersectional targeting of Drd2-expressing POMC neurons, we reveal, that dopamine-mediated POMC neuron inhibition is Drd2-dependent and that POMCDrd2+ neurons exhibit differential expression of neuropeptide signaling mediators, which manifests in enhanced somatostatin responsiveness of these neurons compared to the global POMC neuron population. Retrograde pseudorabies mapping reveals predominant synaptic input onto these cells from within the ARC as well as characterized dopaminergic cell groups within the hypothalamus and subthalamic areas. Finally, selective chemogenetic activation of POMCDrd2+ neurons uncovers their ability to acutely suppress feeding and to preserve body temperature. Collectively, the present study provides the molecular and functional characterization of POMCDrd2+ neurons and aids to our understanding of dopamine-dependent control of homeostatic energy regulatory neurocircuits. Overall design: In order to characterize the translational profile of POMCDrd2+ neuronal subpopulation, we crossed POMCDre Drd2Cre double transgenic mice with those allowing for restricted expression of a fusion protein of the ribosomal protein L10a and EGFP solely in presence of both Cre and Dre recombinases (R26-lx-rx-EGFP-L10a). Pull-down of EGFP-tagged ribosomes from POMCDrd2+ neurons and subsequent mRNA sequencing of ribosome-associated mRNAs allowed for enrichment of actively translated mRNAs originating from Drd2-expressing POMC neurons. Analogous, we also performed RNA sequencing of ribosome-associated mRNA from the global POMC neuronal population targeted by the POMCDre transgene. To this end, we crossed POMCDre mice with those expressing EGFP-L10a in a Dre-only dependent manner (R26-rx-EGFP-L10a) to obtain a translational profile of the entire POMC neuron population targeted in POMCDre mice.