Exendin-4 attenuates cardiac hypertrophy via AMPK/mTOR signaling pathway activation

Area of Science:

• Cardiology
• Endocrinology
• Molecular Biology

Background:

• Diabetes mellitus is a major risk factor for cardiovascular diseases, particularly diabetic cardiomyopathy.
• Diabetic cardiomyopathy is characterized by cardiac hypertrophy, a precursor to heart failure.
• Glucagon-like peptide 1 (GLP-1) has known cardiovascular benefits, but its role in cardiac hypertrophy is unclear.

Purpose of the Study:

• To investigate the role of GLP-1 signaling in cardiac hypertrophy.
• To determine the effects of exendin-4, a GLP-1 receptor agonist, on cardiac hypertrophy.
• To elucidate the underlying molecular mechanisms, including signaling pathways involved.

Main Methods:

• Phenylephrine (PE)-induced cardiac hypertrophy model in vitro.
• Treatment with exendin-4 and GLP-1 receptor antagonist exendin9-39.
• Assessment of cardiac hypertrophic markers (ANP, BNP, β-MHC) and cell surface area.
• Analysis of Erk1/2 and AMPK signaling pathways.
• Investigation of the mTOR/p70S6K/4-EBP1 pathway and rapamycin effects.

Main Results:

• Exendin-4 treatment significantly ameliorated PE-induced cardiac hypertrophy, reducing hypertrophic markers and cell size.
• The anti-hypertrophic effect of exendin-4 was reversed by exendin9-39.
• Exendin-4 activated the AMPK signaling pathway, which was crucial for its anti-hypertrophic effect.
• Exendin-4's action involved the mTOR/p70S6K/4-EBP1 pathway, and it enhanced rapamycin's effect.

Conclusions:

• Exendin-4 inhibits cardiac hypertrophy by upregulating GLP-1 receptor expression.
• The AMPK/mTOR signaling pathway is a key mediator of exendin-4's anti-hypertrophic effects.
• Exendin-4 represents a potential therapeutic agent for diabetic cardiomyopathy and related cardiac hypertrophy.