Abstract
Purpose :
We previously reported that 6 transcription factors including ovo-like zinc finger 2 (OVOL2) were able to be directly induced corneal epithelial cells (CECs) from skin fibroblasts. (ARVO 2015) The purpose of this present study was to clarify how OVOL2 regulates the cell identity of human corneal epithelial cells (hCECs).We previously reported that 6 transcription factors including ovo-like zinc finger 2 (OVOL2) were able to be directly induce corneal epithelial cells (CECs) from skin fibroblasts. (ARVO 2015). The purpose of this present study was to clarify how OVOL2 regulates the cell identity of human corneal epithelial cells (hCECs).
Methods :
To perform a functional analysis of OVOL2, we examined the expression pattern of OVOL2 in the human corneal epithelium using an in vivo human cornea. Next, we examined the OVOL2 function using siRNA targeted for OVOL2 in primary hCECs in regard to the gene expression changes and barrier function. Finally, ChiP-seq analysis for OVOL2 was performed in order to analyze global gene regulation.
Results :
Immunohistochemistry examination of the corneal epithelium showed that OVOL2 was expressed throughout all layers. Morphologically, hCECs with siOVOL2 became elongated fibroblastic cells. Immunocytochemistry of hCECs with siOVOL2 showed reduction of K12 and E-cadherin proteins. Moreover, OVOL2 knockdown significantly reduced barrier function of primary hCECs measured by transepithelial electrical resistance. Global expression analyses between hCECs and hCECs treated with siOVOL2 by microarray revealed that among the 42,545 genes analyzed, 805 genes were differentially expressed by more than 1.5 fold, and 320 genes upregulated and 485 genes downregulated in hCECs with siOVOL2. Downregulated genes enriched Gene Ontology terms related to epithelial functions. ChIP-seq analysis using hCECs showed OVOL2 peaks on ZEB1 and ZEB2, which are mesenchymal-related genes.
Conclusions :
The findings of this study show that OVOL2 maintains the transcriptional program of human corneal epithelium by suppressing epithelial-to-mesenchymal transition.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.