Primary cilia regulate GLP-1 signaling in pancreatic β cells

Area of Science:

• Cell Biology
• Endocrinology
• Metabolic Diseases

Background:

• Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are key treatments for diabetes and obesity.
• The role of primary cilia in beta-cell incretin response was previously unknown.

Purpose of the Study:

• To investigate the role of primary cilia in GLP-1 receptor (GLP-1R) signaling within beta cells.
• To determine if primary cilia are essential for GLP-1R-mediated insulin secretion.

Main Methods:

• Studied beta-cell primary cilia function in mouse and human islets.
• Utilized immunofluorescence and immunogold scanning electron microscopy to localize GLP-1R.
• Investigated the effect of Tulp3 knockdown on ciliary GPCR trafficking and signaling.

Main Results:

• Loss of beta-cell cilia significantly impaired GLP-1-potentiated insulin secretion.
• Blunted cAMP and Ca²⁺ responses were observed in cells lacking cilia.
• GLP-1R was found to localize to the primary cilium.
• Disrupting ciliary GPCR trafficking mimicked the signaling deficits.

Conclusions:

• Primary cilia are a critical, non-redundant signaling compartment for GLP-1R.
• This highlights a novel subcellular organization mechanism in incretin action within beta cells.
• Findings offer new insights into the cellular basis of diabetes and obesity therapies.