Abstract
Purpose :
To examine if expression of amphiregulin in healing mouse conjunctiva after incision and if TGFb1 upregulates its expression in cultured fibroblasts. Effect of adding an EGFR inhibitor, PD168393, on fibrogenic gene expression and in vitro defect closure in the cells was also examined.
Methods :
Expression pattern of amphiregulin and phospho-EGFR (pEGFR) in healing conjunctiva following circumferential incision at until day 7 by using immunohistochemistry. Effects of adding an EGFR inhibitor, PD168393, and/or TGFb1 on the closure of a liner defect produced in a confluent fibroblast culture were evaluated. Effects of adding TGFb1 on protein expression of EGFR ligands; EGF, amphiregulin, TGFα, were examined. Effects of adding TGFb1 and/or PD168393 on mRNA expression of collagen Ia1 and a-smooth muscle actin, a myofibroblast marker, were finally studied.
Results :
Protein expression of amphiregulin and pEGFR was upregulated in healing conjunctiva upto until day 7. Inhibition of EGFR by PD168393 delayed defect closure of fibroblast monolayer culture. Adding TGFb1 upregulated protein expression of EGF, amphiregulin and TGFα in fibroblast culture. Myofibroblast generation by adding TGFb1 was counteracted by further addition of PD168393, while collagen Ia1 upregulation by TGFb1 was not affected by adding PD168393.
Conclusions :
In vivo wounding upregulates expression of amphiregulin and phosphorylation of EGFR and the situation was mimicked in cell culture with TGFb1. Inhibition of EGFR counteracted TGFb1-induced myofibroblst generation in vitro was not affected by EGFR inhibition. Amphiregulin-EGFR system is considered to have a significant role in conjunctival wound healing.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.