Extracellular matrix gene expression in human trabecular meshwork cells following mechanical fluid flow stimulation

Area of Science:

• Ocular biology
• Cellular mechanotransduction
• Extracellular matrix dynamics

Background:

• The trabecular meshwork (TM) is crucial for regulating intraocular pressure (IOP).
• Mechanical forces from aqueous humor flow are hypothesized to influence TM cell behavior.
• Understanding TM cell response to mechanical stimuli is key to IOP regulation.

Purpose of the Study:

• To examine how mechanical fluid flow affects extracellular matrix (ECM) gene expression in human trabecular meshwork (HTM) cells.
• To investigate the role of Smad2 signaling in response to mechanical stimulation.

Main Methods:

• HTM cells were subjected to varying levels of shear stress (0-1.0 dyne/cm²) on collagen-coated plates.
• Gene expression changes related to ECM were quantified using real-time RT-PCR.
• Smad2 protein phosphorylation was assessed via Western blotting.

Main Results:

• Mechanical stimulation significantly upregulated mRNA for COL4A2, COL6A1, and fibronectin-1.
• Metalloproteinase-2 and plasminogen activator inhibitor-1 mRNA levels also increased significantly.
• Smad2 protein phosphorylation was elevated following mechanical stimulation.

Conclusions:

• Mechanical fluid flow significantly alters ECM gene expression in HTM cells.
• These changes indicate that mechanical stimulation promotes ECM turnover.
• This ECM remodeling may play a role in maintaining intraocular pressure homeostasis.