Abstract
Purpose :
The role of activated focal adhesion kinase (FAK) signaling pathway in posterior capsule pacification (PCO) remains unclear. Fibronectin, a component of the extracellular matrix, was previously reported to secrete increasingly induced by transforming growth factor (TGF-β2) and interact with integrins on the cell surface. We tested the hypothesis that FAK plays a role in TGF-β2 induced migration in human lens epithelial cells, which was mediated by fibronectin.
Methods :
The HLE-B3 cells, a human lens epithelial cell line, was incubated with TGF-β2 (5ng/ml). The expression of fibronectin , p-FAK and FAK were determined by western-blot analysis and expression of integrin α5β1 on the cell surface were detected by flow cytometry. HLE-B3 cells were seeded on culture surface coated with fibronectin (10μg/ml,50μg/ml), polylysine or collagen. Cell adhesion were quantified by crystal violet staining (0.5%). Cell migration capacity were measured by wound-healing assay and transwell migration assay in presence or absence of a FAK inhibitor, fibronectin RNA interference or RGD, which inhibits interaction of integrin and fibronectin. T-test was used for statistical analysis.
Results :
TGF-β2 promoted HLE-B3 cell migration in a dose-dependent manner. TGF-β2 upregulated fibronectin expression (p = 0.007), which was followed by increased phosphorylation of FAK (p = 0.001). Meanwhile, we found that integrin α5β1 was abundantly expressed on cell surface. Disrupting intergrin-fibronection interaction by RGD reduced TGF-β2-induced cell migration. Moreover, cell adhesion (1.50±0.17, p = 0.030), migration (2.25±0.10, p = 0.0007) and p-FAK expression (2.64±0.03, p = 0.0002) were markedly increased on a fibronectin-coated surface compared to polylysine-coated or collagen-coated ones, which was abolished by RGD treatment. Suppression of FAK signaling by its inhibitor or fibronectin SiRNA attenuated TGF-β2-induced HLE-B3 migration (p = 0.0001).
Conclusions :
Our results are consistent with our hypothesis that TGF-β2 can induce phosphorylation of FAK and, subsequently, promote cell migration, which was mediated by fibronectin in human lens epithelial cells.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.