Abstract
Purpose:
Factors that maintain the limbal epithelial stem/progenitor cells in vitro have not been completely defined. In this study we examined the effect of rapamycin, an inhibitor of the mTOR pathway, on the colony forming efficiency of corneal epithelial cells.
Methods:
Primary human corneal epithelial cells were grown in KSFM (keratinocyte serum free media) and at the same time treated with a range of concentrations of Rapamycin. Control cultures were treated with the vehicle (DMSO). After growing in Rapamycin or DMSO for 7-10 days, the cells were passaged and plated on mitomycin C treated fibroblasts (no further rapamycin or DMSO treatment given). Colony forming efficiency was determined by counting the number of colonies visualized by crystal violet.
Results:
Rapamycin appeared to have toxic effects at higher concentrations but at low concentrations it appeared to reduce the proliferation of corneal epithelial cells compared to DMSO. Cells that were treated with Rapamycin subsequently demonstrated higher colony forming efficiency compared to DMSO.
Conclusions:
These results suggest that rapamycin helps to maintain colony forming efficiency in corneal epithelial cells. It is unclear at this time whether these effects are simply due to the fact that rapamycin also reduces proliferation. Further gene expression studies are needed to determine whether rapamycin helps to maintain cells in a less differentiated state.
Keywords: 482 cornea: epithelium •
449 cell survival •
721 stem cells