A20 Attenuates the Fibrotic Response in the Trabecular Meshwork

Area of Science:

• Ophthalmology
• Molecular Biology
• Cell Biology

Background:

• The extracellular matrix (ECM) in trabecular meshwork (TM) is crucial for regulating intraocular pressure (IOP).
• Molecular mechanisms driving glaucomatous TM fibrosis are not fully understood.
• Transforming growth factor beta 2 (TGFβ2)-toll-like receptor 4 (TLR4) signaling crosstalk is implicated in TM fibrosis and glaucomatous damage.

Purpose of the Study:

• To investigate the role of A20 (TNFAIP3) as a novel molecular target to inhibit pathological TGFβ2-TLR4 signaling in TM.
• To evaluate A20's potential to counteract fibrotic responses in the TM.

Main Methods:

• Primary human TM cells were treated with TGFβ2 to analyze A20 and fibronectin expression.
• A20 was overexpressed in TM cells to assess its effect on TGFβ2, lipopolysaccharide (LPS), or cellular fibronectin extra domain A (cFN-EDA) treatment.
• In situ hybridization was used to examine A20 RNA expression in a novel mouse model of glaucoma.

Main Results:

• TGFβ2 treatment decreased A20 expression while increasing fibronectin, a marker of fibrosis.
• Overexpression of A20 in TM cells rescued the fibrotic response induced by TGFβ2, LPS, or cFN-EDA.
• A20 RNA expression showed cyclic increases in a mouse model of glaucoma at specific ages.

Conclusions:

• A20 may act as a negative feedback regulator, attenuating TGFβ2-TLR4 signaling-induced fibrosis in the TM.
• Targeting A20 presents a potential therapeutic strategy for managing glaucomatous fibrosis.
• Further research into A20's mechanism could elucidate novel approaches for glaucoma treatment.