Abstract
Purpose :
In corneal wound healing, the transformation of quiescent keratocytes to activated fibroblasts and subsequently myofibroblasts (KFM transformation) is promoted by transforming growth factor-β (TGF-β). This process is critical for wound healing; however, excessive numbers and/or prolonged persistence of myofibroblasts in the wound space has been associated with stromal haze formation. We hypothesized that hepatocyte growth factor (HGF), which can counteract TGF-β signaling, would decrease myofibroblast transformation. In this study, we tested this hypothesis by analyzing the expression of α-smooth muscle actin (α-SMA) as a marker of myofibroblast phenotype after exposure to TGF-β1 in the presence and absence of HGF.
Methods :
Human corneal fibroblasts (HCFs) were isolated and cultured on tissue culture plastic in media containing varying concentrations of TGF-β1 (0.5 to 10 ng/ml) ± HGF (5 to 50 ng/ml) for 24 hours. RNA and protein were collected from cells, and were analyzed for the expression of α-SMA, using quantitative PCR, Western blot and immunocytochemistry.
Results :
In primary HCFs, the mRNA expression of α-SMA showed a clear response to TGF-β1. Expression increased by 3.72 fold with 2 ng/ml TGF-β1 (p<0.001). Expression was suppressed to two-thirds when cells were incubated with 20 ng/ml HGF in the presence of 2 ng/ml of TGF-β1 (p<0.01). Using Western blot and immunocytochemistry, protein expression of α-SMA was also decreased by 20 ng/ml of HGF to less than half of that induced by TGF-β1 (p<0.01).
Conclusions :
We have demonstrated that HGF can decrease KFM transformation promoted by TGF-β1. These data suggest that HGF holds the potential as a therapeutic agent to minimize corneal fibrosis after wounding.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.