GLP1R

Overview

The glucagon-like peptide-1 receptor (GLP-1R), encoded by the gene GLP1R (Wikidata: Q14909910), is a class B G protein-coupled receptor (GPCR) expressed predominantly in pancreatic β-cells, the gastrointestinal tract, the heart, the kidneys, and select regions of the central nervous system. Upon binding its endogenous ligand, glucagon-like peptide-1 (GLP-1), the receptor activates intracellular cyclic AMP (cAMP) signaling and downstream effectors including cAMP-dependent protein kinase catalytic subunit (PKA), thereby stimulating glucose-dependent insulin secretion, suppressing glucagon release, slowing gastric emptying, and reducing food intake. These pleiotropic metabolic effects have made GLP-1R one of the most clinically important drug targets of the past two decades. Pharmacological agonists such as liraglutide and related analogs are now in widespread use for the management of type 2 diabetes and obesity, while the receptor's broader roles in cardiovascular protection, oncology, neuropsychiatry, and β-cell mass quantification have become active frontiers of translational research.

The receptor's expression on pancreatic β-cells has particular physiological relevance: GLP-1R density serves as a surrogate marker for functional β-cell mass, an insight that has catalyzed the development of non-invasive imaging strategies for staging metabolic disease. Beyond the pancreas, GLP-1R is increasingly recognized as a mediator at the gut-brain axis, linking intestinal microbiota composition and peripheral hormonal signals to central mood and behavior regulation. Its emerging roles in heart failure risk reduction, anticancer signaling, and multi-target drug design underscore the receptor's centrality across multiple disease areas.

Focus of Latest Publications

Recent publications on GLP1R continue to emphasize its central role in metabolic disease therapeutics, with most studies focusing on GLP-1 receptor agonism, antagonism, or receptor-targeted delivery strategies. Several reports examined liraglutide or exendin-4–based approaches in diabetes, obesity, and related complications, while others explored GLP1R as a molecular target for imaging, computational screening, or drug design. Collectively, these studies highlight GLP1R as a versatile target for improving glycemic control, extending peptide drug exposure, and enabling tissue-specific delivery or diagnosis.

In type 2 diabetes research, GLP1R was used to support multiple therapeutic innovations. One study developed a subcutaneous nanoplatform for sitagliptin delivery by conjugating exenatide to chitosan-selenium nanoparticles, explicitly leveraging GLP-1 receptor affinity for pancreatic targeting and reporting controlled biphasic release with high encapsulation efficiency. Another engineered IgG Fc-binding motif-conjugated exendin-4 analogues to prolong plasma half-life through endogenous IgG engagement; the lead compound retained robust GLP1R activation, lowered glucose acutely, and in db/db mice produced a hypoglycemic duration comparable to semaglutide, with chronic dosing reducing HbA1c and protecting pancreatic islets without toxicity. In parallel, computational work identified oral candidate molecules and natural products with predicted or validated GLP1R activity, including Fmol021 in an in silico obesity study and xanthohumol and cirsilineol in a combined computational-experimental screen, where the latter increased glucose-stimulated insulin secretion in MIN6 cells to levels comparable to exendin-4.

Beyond glucose lowering, GLP1R-targeted studies also extended into imaging and broader disease biology. A PET tracer based on exendin-4, [18F]FB(ePEG12)12-exendin-4, was evaluated for noninvasive assessment of pancreatic β-cell mass in type 1 diabetes, showing lower pancreatic uptake in affected individuals and correlations with fasting C-peptide index, HbA1c, and insulin dose. Another study used GLP1R-targeted imaging to help redefine disease staging and glycemic control. In cardiovascular and hepatic contexts, a clinical study examined dapagliflozin and dulaglutide in patients with type 2 diabetes and metabolic dysfunction–associated steatotic liver disease, reflecting continued interest in GLP-1 receptor agonists for cardiometabolic outcomes. Mendelian randomization work also suggested novel beneficial effects of GLP-1 receptor agonists in heart failure.

Several recent papers explored GLP1R signaling in nontraditional settings. In rodent neurobiology, systemic liraglutide was reported to act through GLP-1 receptor-expressing neurons in a lateral septum GABAergic microcircuit to inhibit alcohol intake and seeking. In aged mice, liraglutide improved postoperative cognitive impairment, with effects linked to activation of the GLP-1R/NRF2/NLRP3 axis, reduced reactive oxygen species, suppression of NLRP3 inflammasome components, and microglia-dependent neuroprotection. In cancer cell models, liraglutide increased GLP1R expression and cAMP/PKA signaling in MCF7 and PC-3 cells, promoted apoptosis and cell-cycle arrest, suppressed PI3K/Akt/mTOR and glycolytic regulators, and altered adipokines and oxidative stress markers. Finally, a GLP1R antagonist, imapextide, was described as a sustained-action, selective, reversible agent intended for once-weekly treatment of postbariatric hypoglycemia, underscoring that both agonism and antagonism of GLP1R are being actively pursued for distinct clinical indications.