Abstract
Purpose :
Hepatocyte growth factor (HGF) is a mitogen and motility factor that regulates epithelial cell function. In the present study, we investigated the effect of HGF on corneal epithelial cell regeneration in inflamed conditions both in vitro and in vivo in a mouse model of corneal injury.
Methods :
Immortalized human corneal epithelial cells (HCEC) were grown in supplemented keratinocyte serum-free medium (KSFM) in the presence or absence of IL1β with or without 100ng/ml HGF, and cell proliferation was evaluated using bromodeoxyuridine labeling. The in vitro effect of HGF on inflammatory cell activation was evaluated by stimulating CD11b+ immune cells with IL1β, with or without HGF, and assessing expression of MHC-II, IL1β, and TNFα using flow cytometry and RT-PCR. Corneal injury was induced in C57BL/6 mice by mechanical removal of the epithelium, and either 0.1% murine recombinant HGF or mouse serum albumin was applied topically to mice twice a day for 7 days. Corneal fluorescein staining was performed daily to evaluate epithelial regeneration. Corneas were harvested on day 3 post-injury to evaluate CD45+ cell infiltration, proliferating Ki67+ epithelial cells, and inflammatory cytokine expression using immunohistochemistry and RT-PCR.
Results :
HCEC proliferation was significantly increased in cells cultured in supplemented KSFM in the presence of HGF compared to supplemented KSFM alone (p<0.02). While the addition of IL1β to the culture medium suppressed HCEC proliferation (p<0.016), HGF significantly reversed the inhibitory effect of IL1β on epithelial cell proliferation (p<0.01). Furthermore, HGF substantially inhibited upregulation of MHC-II activation marker and significantly suppressed the expression of IL1β and TNFα by CD11b+ inflammatory cells (p< 0.01). Finally, mice treated with topical HGF demonstrated faster corneal epithelial regeneration as elucidated by smaller area of corneal fluorescein uptake, higher numbers of proliferating Ki67+ cells (p<0.02), less CD45+ cell infiltration into the cornea and lower IL1β and TNFα expression levels compared to serum albumin-treated controls (p<0.01).
Conclusions :
Our data provide evidence that HGF exerts anti-inflammatory function and promotes corneal epithelial repair during injury and inflammation. These findings suggest that HGF may serve as a potential novel therapeutic modality for epithelial defects.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.