Functional impact of collagens on the activity directed by the promoter of the a5 integrin subunit gene in corneal epithelial cells

ABSTRACT: Important remodeling of the extracellular matrix is a hallmark of corneal wound healing. Besides the massive secretion of fibronectin (FN) that characterizes the early step of that process, alterations in the secretion of collagens also occurs as part of this wound healingresponse. In this study, we examined whether expression of the gene encoding the α5 subunit from the FN binding integrin α5β1 changes as corneal epithelial cells (CECs) are cultured in the presence of collagens. Responsiveness of the α5 gene toward collagen was determined by transfection of recombinant plasmids bearing the CAT reporter gene under the control of various segments from the human α5 promoter into primary cultured rabbit (RCECs) and human (HCECs) CECs cultured on BSA or on collagens. Electrophoretic mobility shift assays (EMSAs) and Western blot analyses were used to monitor both the DNA binding and expression of the transcription factors required to ensure basal transcription of the α5 gene. The influence collagens on the patterns of genes expressed by HCECs was also studied be gene profiling on microarrays. All collagen types repressed the transcriptional activity directed by the full-length α5 promoter/CAT construct in confluent CECs. A moderate increase in α5 promoter activity was observed in subconfluent RCECs grown on CIV but not on CI. These collagen-dependent regulatory influences also correlated with alterations in either the expression or the DNA binding of the transcription factors Sp1/Sp3, NFI and AP-1 that ensure basal transcription of the α5 gene. Gene profiling on microarray revealed that CI more profoundly alter the pattern of genes expressed by HCECs than what is observed with CIV. Collagens considerably suppressed expression of the α5 gene in CECs at confluence suggesting that the sustained staining for CI and CIV after corneal injury may play a role in controlling adhesion to the temporary FN matrix and further differentiation of CECs into suprabasal epithelial cells through a mechanism involving the α5β1 integrin.

ORGANISM(S): Homo sapiens

PROVIDER: GSE65421 | GEO | 2015/01/30

SECONDARY ACCESSION(S): PRJNA273984

REPOSITORIES: GEO