Article Impact Level: HIGH Data Quality: STRONG Summary of Nature Metabolism. https://doi.org/10.1038/s42255-025-01342-6 Dr. Anne de Bray et al.
Points
- Researchers created fluorescent probes called daLUXendins to track the interaction of GLP1R/GIPR dual agonist drugs, such as tirzepatide, with specific cells throughout the body.
- In the pancreas, the probes demonstrated strong binding to insulin-producing beta cells, as well as significant engagement with both alpha and delta cells, thereby clarifying their broad metabolic effects.
- The drugs successfully reached appetite-regulating neurons in brain regions with a porous blood-brain barrier but did not penetrate deeper into the brain than single-agonist drugs.
- At the molecular level, super-resolution microscopy showed that dual agonists target unique clusters of receptors, known as nanodomains, which differ from those engaged by single agonists.
- This evidence suggests that the superior efficacy of dual agonists is driven by their unique action in the pancreas and accessible brain areas, rather than by deep-brain access.
Summary
A recent study investigated the cellular and molecular mechanisms underlying the superior efficacy of dual glucagon-like peptide-1 receptor (GLP-1R) and glucose-dependent insulinotropic polypeptide receptor (GIPR) agonists compared to single GLP-1R agonists. To delineate in situ drug targets, researchers developed and validated novel non-lipidated (daLUXendin) and lipidated (daLUXendin+) fluorescent dual agonist probes. These probes act as potent GLP1R/GIPR agonists and were used to visualize drug engagement in rodent and human tissues, addressing a key challenge posed by the unreliability of antibody-based receptor detection methods.
In ex vivo studies of pancreatic islets, daLUXendins labeled multiple endocrine cell types, demonstrating a signal intensity hierarchy of β cells > α cells = δ cells. Following systemic administration in murine models, the probes accumulated in GLP1R+ and GIPR+ neurons within circumventricular organs, which are characterized by an incomplete blood-brain barrier. However, the study found no evidence of enhanced brain penetration beyond these accessible regions when compared to single-target (ant)agonists, suggesting that superior central nervous system access is not the primary driver of the dual agonists’ enhanced therapeutic effects for weight reduction and glucose control.
Using super-resolution microscopy, the investigation revealed that daLUXendin targets endogenous GLP1R–GIPR nanodomains on the cell surface. The distinct organization and composition of these clusters, compared to those targeted by single agonists, point to a different mode of signal amplification. These findings provide a high-resolution map of dual agonist targets, clarifying their mode of action in the pancreas and accessible brain regions while excluding a central role for deep brain penetration in their superior clinical efficacy.
Link to the article: https://www.nature.com/articles/s42255-025-01342-6
References De Bray, A., Roberts, A. G., Armour, S., Tong, J., Huhn, C., Gatin-Fraudet, B., Roßmann, K., Shilleh, A. H., Jiang, W., Figueredo Burgos, N. S., Trott, J. P. P., Viloria, K., Nasteska, D., Pearce, A., Miyazaki, S., Tomlinson, J. W., Owen, D. M., Nieves, D. J., Ast, J., … Hodson, D. J. (2025). Fluorescent GLP1R/GIPR dual agonist probes reveal cell targets in the pancreas and brain. Nature Metabolism. https://doi.org/10.1038/s42255-025-01342-6
