Abstract
Purpose::
The barrier function of corneal epithelial cells is important for maintenance of corneal homeostasis. Furthermore, the functions of corneal epithelial cells and corneal fibroblasts are regulated reciprocally through the production of various cytokines and growth factors. We have now examined the effects of corneal fibroblasts on the expression of tight-junction proteins in corneal epithelial cells.
Methods::
Simian virus 40-transformed human corneal epithelial (HCE) cells and human corneal fibroblasts were cultured on opposite sides of a collagen vitrigel membrane. Expression of the tight-junction proteins ZO-1, occludin, and claudin in HCE cells was examined by reverse transcription-polymerase chain reaction (RT-PCR) and immunoblot analyses.
Results::
RT-PCR analysis revealed that the abundance of ZO-1, occludin, and claudin mRNAs in HCE cells was increased in the presence of corneal fibroblasts compared with that apparent in their absence. Immunoblot analysis also showed that the amounts of the corresponding proteins were increased by the presence of corneal fibroblasts. The increases in the amounts of these mRNAs and proteins were maximal 24 hours after the onset of coculture of the two cell types.
Conclusions::
Coculture of HCE cells and human corneal fibroblasts separated by a collagen membrane provides an in vitro model for studies of the interactions between these two cell types in vivo. Corneal fibroblasts were shown to increase the expression of tight-junction proteins in HCE cells at both the mRNA and protein levels, suggesting that corneal fibroblasts may play a role in the differentiation of corneal epithelial cells.
Keywords: cornea: basic science • differentiation • cell-cell communication