Targeting GLP-1 receptor trafficking to improve agonist efficacy

Area of Science:

• Pharmacology
• Endocrinology
• Molecular Biology

Background:

• Glucagon-like peptide-1 receptor (GLP-1R) activation is key for insulin secretion and weight management, making it a target for type 2 diabetes (T2D).
• GLP-1R, a G protein-coupled receptor, undergoes endocytosis upon agonist binding, but the impact of this trafficking on therapeutic outcomes remains unclear.

Purpose of the Study:

• To investigate how biased GLP-1R agonists with varying internalization and recycling propensities affect receptor function.
• To determine if modulating GLP-1R endocytic trafficking can lead to improved efficacy and tolerability in T2D treatment.

Main Methods:

• Studied a series of biased GLP-1R agonists with differential effects on receptor internalization and recycling.
• Compared these novel agonists to FDA-approved GLP-1 mimetics in vitro and in vivo mouse models.
• Assessed insulin release, β-arrestin recruitment, agonist dissociation rates, and glycemic control.

Main Results:

• Compounds that maintain GLP-1R at the plasma membrane promoted sustained insulin release compared to standard GLP-1 mimetics.
• This enhanced effect correlated with reduced β-arrestin recruitment and faster agonist dissociation.
• Agents with specific GLP-1R trafficking profiles demonstrated glycemic benefits in mice without increasing nausea-related side effects.

Conclusions:

• Modulating GLP-1R endocytic trafficking offers a promising strategy for developing more effective and tolerable T2D therapies.
• Biased agonists that limit receptor internalization may provide sustained insulinotropic effects and reduce adverse events like nausea.
• This research identifies novel therapeutic agents with distinct GLP-1R trafficking characteristics for potential T2D treatment.