Abstract
PURPOSE
Proliferation and degeneration of ocular fibroblasts are major obstacles to pterygium treatment, which involves a variety of important proteins and signaling pathways; however, the underlying mechanisms are largely unknown. The aim of this study was to investigate the role and potential mechanisms of P53 and mammalian target of rapamycin (mTOR) in transforming growth factor beta 1 (TGF-β1)-induced proliferation and transdifferentiation of pterygium fibroblasts (HPFs).
METHODS
The proliferation and transdifferentiation indexes of HPFs cultured in vitro and normal conjunctival fibroblasts (HCFs) were compared, and their differences in TGF-β1, P53, and mTOR expression were determined. Further, HPFs were induced with TGF-β1 in vitro and treated with combined knockdown of P53, P53 activator Nutlin-3, or mTOR inhibitor rapamycin to observe cell proliferation, migration, and transdifferentiation.
RESULTS
TGF-β1, P53, mTOR, proliferating cell nuclear antigen (PCNA), and alpha smooth muscle actin (α-SMA) were up-regulated in the expression of HPFs. TGF-β1 treatment induced the proliferation and transdifferentiation of HPFs. TGF-β1 combined with rapamycin treatment substantially inhibited the proliferation and transdifferentiation process of HPFs induced by TGF-β1. TGF-β1 combined with the knockdown of P53 treatment showed that the proliferative ability of HPFs was enhanced, whereas the expression of α-SMA was weakened; in the TGF-β1 combined with Nutlin-3 treatment, the proliferation ability of HPFs was weakened, whereas the expression of α-SMA was enhanced. In TGF-β1-induced HPFs, knockdown or activation of P53 affected the expression of AMP-activated protein kinase (AMPK), phosphorylated AMPK (p-AMPK), mTOR, and phosphorylated mTor (p-mTOR); therefore, the P53/AMPK/mTOR route may be partially involved in the proliferation and transdifferentiation process of TGF-β1-induced HPFs.
CONCLUSIONS
There may be some kind of crosstalk between P53 and mTOR in the proliferation and transdifferentiation of TGF-β1-induced HPFs, and the P53/AMPK/mTOR route may be partially involved in the proliferation and transdifferentiation of TGF-β1-induced HPFs.