FoxO1 mediates TGF-beta1-dependent cardiac myofibroblast differentiation

Area of Science:

• Cardiovascular biology
• Cellular signaling
• Fibrosis research

Background:

• Cardiac fibroblast differentiation to myofibroblasts drives cardiac fibrosis.
• Transforming growth factor beta-1 (TGF-β1) is a key regulator of this process.
• The role of transcription factor forkhead box O1 (FoxO1) in this context is not fully understood.

Purpose of the Study:

• To investigate the role of FoxO1 in TGF-β1-mediated cardiac fibroblast differentiation.
• To elucidate the regulatory mechanisms of FoxO1 by TGF-β1.

Main Methods:

• Cultured cardiac fibroblasts were treated with TGF-β1.
• FoxO1 expression, localization, and activity were assessed.
• Cardiac fibroblast differentiation markers (α-smooth muscle actin, CTGF, pro-collagen I) and proliferation were measured.
• Cell cycle arrest (p21waf/cip) and contractile capacity were evaluated.
• FoxO1 was manipulated (down-regulation/overexpression) to assess its functional impact.

Main Results:

• TGF-β1 increased FoxO1 expression, dephosphorylation, nuclear translocation, and transcriptional activity.
• TGF-β1 promoted cardiac fibroblast differentiation markers and contractile capacity.
• TGF-β1 reduced cardiac fibroblast proliferation and increased p21waf/cip levels.
• FoxO1 manipulation directly influenced TGF-β1's effects on differentiation.

Conclusions:

• FoxO1 is a key mediator of TGF-β1-induced cardiac fibroblast differentiation.
• FoxO1 is regulated by TGF-β1 signaling.
• FoxO1 represents a potential therapeutic target for anti-fibrotic strategies.