Genomes and Genes
MOLECULAR ASPECTS OF CORNEAL EPITHELIAL MIGRATION
Principal Investigator: MARY STEPP
Affiliation: George Washington University
Abstract: The corneal epithelium has a variety of cell:cell and cell:substrate contacts which maintain much of its integrity even as it migrates in response to injury. Among the cell:substrate junctions, the hemidesmosomes (HDs) are responsible for most of the adhesion of the epithelium to its substrate. HDs contain the alpha6beta4 integrin as one of their components and other integrin heterodimers are present in cell:cell boundaries of the corneal epithelium. Aim 1 of this proposal is to determine whether the expression and structure of beta1, beta4, alpha3, alpha5 and alpha6 integrin mRNAs are altered during migration by a) amplifying rat integrin cDNAs from a rat corneal epithelial cell library, b) determining if the expression of rat integrin mRNAs is altered during migration, c) determining the relative abundance of the cytoplasmic integrin mRNA alternative splicing variants and whether there are changes during migration, and d) correlating the data on integrin mRNA expression with data on integrin protein synthesis. Aim 2 is to determine if the delay in corneal epithelial migration induced by addition of extracts from rat polymorphonuclear leukocytes (PMNs) to debridement wounded corneal organ cultures involves alterations in the amounts or the localization of integrins by a) using immunoblotting, immunoprecipitation, and mRNA quantitation to discover if the PMN extract added to debridement wounds affects protein synthesis in the epithelium by determining the level of integrins, vinculin, alpha-actin, alpha- enolase, and ICAM-1 and b) determining if the addition of purified inflammatory cytokines to corneal organ cultures with epithelial debridement wounds results in a delay in epithelial migration by a mechanism similar to PMN extract. Aim 3 is to determine whether the disassembly of hemidesmosomes and migration of the corneal epithelium involves phosphorylation and/or proteolytic cleavage of the beta4 subunit by a) determining whether the HD alpha6 and beta4 subunits are phosphorylated on tyrosine in the unwounded cornea and if their phosphorylation state is altered during migration, b) developing polyclonal antisera with specificity against either the entire extracellular domain or the entire cytoplasmic portion of the beta4 molecule, and c) using the antisera to determine if the beta4 molecule undergoes cleavage during epithelial cell migration. Aim 4 is to determine if integrins at regions of cell:cell interaction are functionally important in maintaining cell:cell contacts in the corneal epithelium by a) establishing cell culture conditions for bovine corneal epithelial cells, b) determining the state of assembly of desmosomes, adherins junctions, and alphav- and the beta1-containing cell:cell junctions in cells cultured in low calcium and after shifting cells to high calcium medium, c) determining the effect of adhesion blocking integrin peptides and antibodies on the ability of cultured corneal epithelial cells to maintain cell:cell contact in low and in high calcium media, and d) determining whether addition of PMN extract to cultured cells disrupts cell:cell contacts and the cell:cell localization of alphav and the beta1 integrins in low and high calcium media. These experiments will help accomplish our goal of obtaining a better understanding, at the molecular level, of the role of integrins in the normal cornea and in epithelial cell migration during wound healing.
Funding Period: 1992-07-01 - 1998-04-30
more information: NIH RePORT
- Effect of wound type on Smad 2 and 4 translocationAudrey E K Hutcheon
Schepens Eye Research Institute and Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114, USA
Invest Ophthalmol Vis Sci 46:2362-8. 2005..The Smad pathway does not appear to be essential for migration; rather, it may play a role in resynthesis of the basement membrane...
- Regulation by P2X7: epithelial migration and stromal organization in the corneaCourtney Mayo
Departments of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
Invest Ophthalmol Vis Sci 49:4384-91. 2008..The goal here was to characterize the role of the P2X(7) receptor in the repair of in vivo corneal epithelial debridement wounds and in the structural organization of the corneal stroma...
- BALB/c and C57BL6 mouse strains vary in their ability to heal corneal epithelial debridement woundsSonali Pal-Ghosh
Department of Anatomy and Regenerative Biology, The George Washington University Medical Center, Washington, DC 20037, USA
Exp Eye Res 87:478-86. 2008..These data prove that strain-specific differences in cell migration rate in vivo are present in the cornea and are accompanied by differences in the frequencies of recurrent erosions and corneal epithelial stem cell deficiency...
- Primary dermal fibroblasts derived from sdc-1 deficient mice migrate faster and have altered alphav integrin functionRosalyn A Jurjus
Department of Anatomy and Regenerative Biology, George Washington University Medical School, 2300 I Street NW, Washington, DC 20037, USA
Wound Repair Regen 16:649-60. 2008....
- Reduced migration, altered matrix and enhanced TGFbeta1 signaling are signatures of mouse keratinocytes lacking Sdc1Mary Ann Stepp
Department of Anatomy and Cell Biology, George Washington University Medical School, Washington, DC 20037, USA
J Cell Sci 120:2851-63. 2007..Thus, our results identify TGFbeta1 signaling and Sdc1 expression as important factors regulating integrin surface expression, activity and migration in keratinocyte and provide new insight into the functions regulated by Sdc1...
- The Cdk5 inhibitor olomoucine promotes corneal debridement wound closure in vivoBrajendra K Tripathi
Laboratory of Molecular and Developmental Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
Mol Vis 14:542-9. 2008..To investigate the effect of the Cdk5 inhibitor olomoucine on corneal debridement wound healing in vivo...