IGF-1 Counteracts TGF-β-Mediated Enhancement of Fibronectin for in Vitro Human Lens Epithelial Cells

Abstract

PURPOSE: To determine whether insulin-like growth factor (IGF-1) affects transforming growth factor (TGF-beta)- mediated fibronectin accumulation in human lens epithelial cell line (HLE B-3) cells.

MATERIALS AND METHODS: HLE B-3 cells were incubated for 24 hours with TGF-beta (10 ng/ mL), IGF-1 (10 ng/mL), or both. Expression of the fibronectin gene was determined using a real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Fibronectin levels were examined using western blot analysis and immunofluorescence staining.

RESULTS: Expression of the fibronectin gene was not different between the TGF-beta/IGF-1 treated group and the TGF-beta treated group (p= 0.116). However, western blot analysis demonstrated decreased fibronectin levels in human lens epithelial cells treated with TGF-beta and IGF-1 compared to those treated with TGF-beta only (p < 0.01). Immunofluorescence staining disclosed inhibition of TGF-beta-induced fibronectin in the presence of IGF-1.

CONCLUSION: This study suggests that IGF-1 counteracts TGF-beta-mediated fibronectin accumulation in human lens epithelial cells.