Glucagon modulates proliferation and differentiation of human adipose precursors

Area of Science:

• Metabolic Research
• Adipose Biology
• Endocrinology

Background:

• Glucagon-like peptide 1 receptor agonists (GLP-1RAs) are used for type 2 diabetes and show anti-obesity effects.
• Dual GLP-1R/glucagon receptor (GCGR) agonists are being investigated for adiposity, but mechanisms require clarification.
• Previous studies showed GLP-1 and liraglutide affect human adipose precursor proliferation and differentiation.

Purpose of the Study:

• To investigate the direct effects of glucagon on human adipose-derived stem cells (ASCs) in vitro.
• To determine if glucagon influences ASC proliferation and adipogenesis.
• To identify the receptors involved in glucagon's action on adipose precursors.

Main Methods:

• Primary human ASCs were cultured and treated with glucagon.
• Cell proliferation was assessed via cell count and thymidine incorporation.
• Adipocyte differentiation was evaluated by intracellular fat content and marker gene expression (PPARγ, FABP4, HSL).
• Receptor antagonists for GLP-1R and GCGR were used to test inhibitory effects.
• Receptor presence was confirmed using Western blot, immunofluorescence, and flow cytometry.

Main Results:

• Glucagon significantly inhibited ASC proliferation in a dose- and time-dependent manner.
• Glucagon significantly reduced adipocyte differentiation, decreasing fat accumulation and altering adipocyte marker expression.
• Specific GLP-1R and GCGR antagonists reversed glucagon's inhibitory effects on proliferation and differentiation.
• Both GLP-1R and GCGR were confirmed to be present in ASCs.

Conclusions:

• Glucagon directly inhibits the proliferation and differentiation of human adipose precursors.
• These effects appear to be mediated through both GLP-1R and GCGR.
• The adipose stem cell compartment is identified as a novel target for glucagon.
• These findings may explain weight loss effects observed with dual GLP-1R/glucagon agonists.