Identification of a GABAergic neural circuit governing leptin signaling deficiency-induced obesity

Authors: HAN, YONG - Children'S Nutrition Research Center (CNRC); HE, YANG - Children'S Nutrition Research Center (CNRC); HARRIS, LAUREN - Children'S Nutrition Research Center (CNRC); XU, YONG - Children'S Nutrition Research Center (CNRC); WU, QI - Children'S Nutrition Research Center (CNRC)

Submitted to: eLife
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/24/2023
Publication Date: 4/12/2023
Citation: Han, Y., He, Y., Harris, L., Xu, Y., Wu, Q. 2023. Identification of a GABAergic neural circuit governing leptin signaling deficiency-induced obesity. eLife. 12. Article e82649. https://doi.org/10.7554/eLife.82649.
DOI: https://doi.org/10.7554/eLife.82649

Interpretive Summary: Leptin, a hormone, helps suppress food intake by acting on specific brain cells. However, using leptin as an obesity treatment faces challenges due to its complex effects. Our research reveals that certain brain neural network (namely GABAergic AgRP-DMH circuit) plays a crucial role in regulating leptin’s impact on feeding, blood glucose level, and body weight. By understanding this neural circuit, we open new possibilities for obesity treatment.

Technical Abstract: The hormone leptin is known to robustly suppress food intake by acting upon the leptin receptor (LepR) signaling system residing within the agouti-related protein (AgRP) neurons of the hypothalamus. However, clinical studies indicate that leptin is undesirable as a therapeutic regiment for obesity, which is at least partly attributed to the poorly understood complex secondary structure and key signaling mechanism of the leptin-responsive neural circuit. Here, we show that the LepR- expressing portal neurons send GABAergic projections to a cohort of a3- GABA A receptor expressing neurons within the dorsomedial hypothalamic nucleus (DMH) for the control of leptin-mediated obesity phenotype. We identified the DMH as a key brain region that contributes to the regulation of leptin- mediated feeding. Acute activation of the GABAergic AgRP-DMH circuit promoted food intake and glucose intolerance, while activation of post-synaptic MC4R neurons in the DMH elicited exactly opposite phenotypes. Rapid deletion of LepR from AgRP neurons caused an obesity phenotype which can be rescued by blockage of GABAA receptor in the DMH. Consistent with behavioral results, these DMH neurons displayed suppressed neural activities in response to hunger or hyperglycemia. Furthermore, we identified that a3- GABAA receptor signaling within the DMH exerts potent bi-directional regulation of the central effects of leptin on feeding and body weight. Together, our results demonstrate a novel GABAergic neural circuit governing leptin-mediated feeding and energy balance via a unique a3- GABAA signaling within the secondary leptin-responsive neural circuit, constituting a new avenue for therapeutic interventions in the treatment of obesity and associated comorbidities.