Development of genetically encoded sensors for real-time monitoring of GLP-1 dynamics in the paraventricular nucleus of the hypothalamus

Abstract

Glucagon-like peptide-1 (GLP-1) is a critical neuroendocrine signal involved in glucose homeostasis and appetite regulation. Here, we report the development of genetically encoded fluorescent GLP-1 sensors (GLP-1 RTGR) designed to monitor GLP-1 dynamics in real time within the paraventricular nucleus (PVN) of the hypothalamus in freely behaving mice. By engineering GLP-1 receptors fused to circularly permuted fluorescent proteins, we achieved highly specific and sensitive detection of endogenous GLP-1 release. In vitro, ex vivo, and in vivo validation confirmed that these sensors exhibit robust and selective responses, enabling precise spatiotemporal mapping of GLP-1 fluctuations. Fiber photometry measurements revealed dynamic GLP-1 signaling patterns that correlate with feeding states, increasing postprandially and potentially reflecting satiety signals. Furthermore, preproglucagon knockout models lacking endogenous GLP-1 showed disrupted feeding patterns, underscoring GLP-1’s role in appetite control. Using a moving average crossover analysis, we predicted feeding behavior from GLP-1 fluctuations with high accuracy. Our findings demonstrate that GLP-1 RTGR sensors provide a powerful tool for real-time neuropeptide imaging, offering new insights into the neuroendocrine mechanisms governing energy balance and highlighting potential targets for metabolic disorder therapies.M.S.Includes bibliographical reference