LEAP2 mediates long-term inhibition of orexigenic neurons of the hypothalamus in mice

Liver-expressed antimicrobial peptide 2 (LEAP2) acts via the growth hormone secretagogue receptor (GHSR) to reduce food intake, yet the central mechanisms underlying its anorectic effects remain unclear. Here, we show that circulating LEAP2 accesses discrete brain regions, including the arcuate nucleus of the hypothalamus (ARH), where it targets orexigenic AgRP/NPY neurons. Despite the negligible local expression in the hypothalamus, LEAP2 peptide is detectable in this brain region and in the cerebrospinal fluid, suggesting peripheral origin and central retention. Using fluorescent tracers, in vivo, ex vivo, and in vitro approaches indicate that LEAP2 exhibits prolonged binding to GHSR at the plasma membrane without promoting receptor internalization, thereby limiting subsequent ghrelin action. Using male mice, we found that central or systemic LEAP2 pretreatment results in a sustained inhibition of ghrelin-induced feeding that lasts for several hours after pretreatment. Notably, LEAP2 also suppresses food intake and c-Fos induction triggered by pharmacogenetic activation of AgRP neurons, indicating a broader inhibitory control over these circuits. Together, our findings establish that LEAP2 acts as a persistent inhibitor of hypothalamic orexigenic centers, providing a mechanistic framework for its long-lasting anorectic effects. These results highlight LEAP2 as a key regulator of energy balance and support its potential as a therapeutic target for obesity and metabolic disorders.