Role of epidermal growth factor and epidermal growth factor receptor on hemidesmosome complex formation and integrin subunit β4

Abstract

Epidermal growth factor (EGF) stimulates integrin b4 expression and synthesis in corneal epithelium through ligand binding to the EGF receptor, receptor dimerization and activation of the intracellular domain. We hypothesized that inhibition of EGF receptor messenger RNA (mRNA) would block integrin b4 expression, which is induced by EGF. We also tested the hypothesis that EGF would cause the degradation of hemidesmosomes in control and injured corneal organ cultures. Primary rabbit corneal epithelial cell cultures or corneas were cultured in keratinocyte medium in the presence or absence of an antisense 20-mer phosphorothioate oligonucleotide complementary to the initiation codon region of EGF receptor mRNA. Cells were also cultured in the presence or absence of EGF. Sense and scrambled oligonucleotides similarly modified were used as controls. The concentration of EGF receptor mRNA was semiquantitatively determined by reverse transcriptase/polymerase chain reaction (RT-PCR). We found that transfection did inhibit EGFR expression and migration of epithelial cells and also demonstrated that EGFR mediated expression of integrin b4 mRNA. Injury induced a decrease in hemidesmosomes that was enhanced with EGF but was not caused by the presence of growth factor in unwounded tissue. These results indicate that injury causes the activation of EGFR but that EGF alone is not responsible for the degradation of hemidesmosomes and that other growth factors play a role in the complex repair of wounds in an avascular tissue.

The roles of calcium signaling and ERK1/2 phosphorylation in a Pax6 +/-mouse model of epithelial wound-healing delay

“…EGF receptors are upregulated following corneal injury [ 20 , 44 , 45 ]. We proposed that the EGF response might mediate the rate of wound healing.…”

Therapeutic Effects of Epidermal Growth Factor on Benzalkonium Chloride–Induced Dry Eye in a Mouse Model

“…Other functions of EGF, such as modulation of cell migration, adhesion, and immune response, might also be present. 27,28 Goblet cells are highly specialized epithelial cells located in the apical surface of the conjunctiva. The main functions of goblet cells are synthesizing, storing, and secreting MUC5AC for the mucous component of the tear film.…”

Communication between Corneal Epithelial Cells and Trigeminal Neurons Is Facilitated by Purinergic (P2) and Glutamatergic Receptors

“…The repair requires a controlled and collaborative system of communication between epithelial and neuronal cells to resynthesize the damaged matrix [1], [2], migrate into the wound bed [3]–[5], and return the epithelium to its original architecture. Previous studies have shown that damage to corneal epithelial cells results in release of nucleotides into the extracellular space at the wound site [6]–[8].…”