Physiological Fluid Flow Moderates Fibroblast Responses to TGF-β1

Area of Science:

• Cell Biology
• Biophysics
• Tissue Engineering

Background:

• Fibroblasts are key connective tissue cells responding to mechanical forces from matrix remodeling and fluid movement.
• Transforming growth factor β1 (TGF-β1) induces fibroblast differentiation into myofibroblasts, marked by α-smooth muscle actin (α-SMA).

Purpose of the Study:

• To investigate the impact of physiological fluid flow on human fibroblast differentiation.
• To determine how fluid flow influences fibroblast responses to TGF-β1.

Main Methods:

• Primary human oral and dermal fibroblasts were subjected to physiological fluid flow.
• Gene expression analysis and assessment of myofibroblast markers (α-SMA, collagen IA1) were performed.
• Internalization of caveolin and TGF-β receptor II was examined.

Main Results:

• Fluid flow induced significant gene expression changes, including upregulation of TGFβ signaling and endocytosis pathways.
• Flow increased TGF-β1, activin A, α-SMA, and collagen IA1.
• Combined flow and TGF-β1 led to reduced fibroblast differentiation, potentially due to increased caveolin and TGF-β receptor II internalization.

Conclusions:

• Low levels of fluid flow stimulate myofibroblast differentiation.
• Fluid flow antagonizes the pro-differentiation effects of TGF-β1 in fibroblasts.
• Mechanical forces may buffer cellular responses to chemical signals in vivo, maintaining fibroblast phenotype plasticity.