Cardiac myocyte miR-29 promotes pathological remodeling of the heart by activating Wnt signaling

Area of Science:

• Cardiovascular Biology
• Molecular Cardiology
• MicroRNA Therapeutics

Background:

• Chronic cardiac stress leads to pathological cardiac hypertrophy and fibrosis.
• The microRNA-29 (miR-29) family typically inhibits collagen production in fibroblasts.
• The specific role of miR-29 in cardiac myocytes during stress-induced remodeling was unclear.

Purpose of the Study:

• To investigate the role of miR-29 in cardiac myocytes during pathological cardiac remodeling.
• To determine if miR-29 contributes to cardiac hypertrophy, fibrosis, and dysfunction.
• To explore miR-29 as a potential therapeutic target for heart disease.

Main Methods:

• Utilized a mouse model of cardiac pressure overload.
• Generated global miR-29 knockout mice and performed antimiR-29 infusion.
• Conducted targeted deletion of miR-29 specifically in cardiac myocytes.
• Analyzed cardiac function, hypertrophy, and fibrosis.
• Investigated molecular mechanisms involving Wnt signaling pathway factors.

Main Results:

• Global deletion of miR-29 or antimiR-29 treatment prevented cardiac hypertrophy and fibrosis in pressure-overloaded hearts.
• Targeted deletion of miR-29 in cardiac myocytes was sufficient to prevent cardiac hypertrophy and fibrosis.
• miR-29 directly targets four Wnt signaling pathway factors, de-repressing Wnt signaling in cardiac myocytes.
• These findings indicate miR-29's dominant role in cardiac myocytes drives pathological remodeling.

Conclusions:

• miR-29 promotes pathological cardiac hypertrophy and fibrosis by de-repressing Wnt signaling in cardiac myocytes.
• Inhibition of miR-29 in cardiac myocytes ameliorates cardiac dysfunction and fibrosis.
• Cell- or tissue-specific antimiR-29 delivery represents a promising therapeutic strategy for pathological cardiac remodeling.