Purchase this article with an account.
L. Shelton, J. S. Rada; Transforming Growth Factor Beta-induced Protein (TGFBIp/βig-h3) Expression in Human Scleral Fibroblasts. Invest. Ophthalmol. Vis. Sci. 2009;50(13):3844.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Transforming growth factor beta-induced protein, 68kD (TGFBIp, βig-h3) is a secreted extracellular matrix protein that has been demonstrated to regulate cell adhesion in a variety of cell types. TGFBIp expression in the sclera was recently described and we hypothesize that TGFBIp is expressed by human scleral fibroblasts (HSFs) and is likely to play an important role in scleral fibroblast - extracellular matrix interactions.
TGFBI/TGFBIp expression was determined using RTPCR and immunoblot from 48 hr HSF conditioned media. Liquid-phase cell attachment assays were performed in HSFs, human foreskin fibroblasts (HFFs) and human corneal stroma fibroblasts (HCFs) to assess the affect of cell adhesion to collagen-type I treated with TGFBIp, fibronectin or bovine serum albumin (0 - 50 µg/ml). Binding assays using biotinylated TGFBIp were used to assess TGFBIp binding to the surface of HSFs. Flow cytometric analysis were used to determine integrin expression on HSFs. Immunocytochemistry was used to determine the localization of TGFBIp and integrins on HSFs.
HSFs were found to synthesize and secrete TGFBI/TGFBIp in 48 hour conditioned medium. Treatment of HSFs with TGFBIp (25 µg/ml) resulted in a significant decrease (p ≤ 0.05, two-tailed t-test) of HSF attachment, whereas treatment of HFFs and HCFs had no significant effects as compared to BSA (p = 0.4965 and p = 0.2386, respectively). Integrins vβ3 and vβ5 inhibited binding of TGFBIp to HSFs by 80% and 50%, respectively (p ≤ 0.01, p ≤ 0.05, two-tailed t-test).
The results of this study show that TGFBIp is synthesized and secreted by HSFs. TGFBIp specifically inhibits scleral fibroblast attachment to collagen and may function to regulate the biomechanical properties of the sclera by integrin mediated scleral fibroblast - matrix interactions.
This PDF is available to Subscribers Only