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Abstract
Type IV collagen, a 500-kilodalton (alpha 1)2(alpha 2)1 heterotrimer with noncollagenous domains (NC1) is the major molecule in most basement membranes in the body. In addition to its structural role as scaffolding, type IV collagen is involved in promoting adhesion and migration of various cell types in vitro, including rabbit corneal epithelial cells. This study assessed the effect of purified proteolytic fragments of type IV collagen and selected synthetic peptides derived from the alpha 1 and alpha 2 chains that are related to the adhesion and directed migration of dissociated primary cultured rabbit epithelial cells. Two homologous peptides (HEP-1 and HEP-2) derived from alpha 1 and alpha 2 NC1 regions were found to promote epithelial cell adhesion. A peptide (HEP-3) derived from an interruption of the triple helix of type IV collagen was effective in promoting corneal epithelial cell migration in both chemotaxis and haptotaxis assays. The helical fragment of type IV collagen promoted both directed migration and ample adhesion, indicating that there may be at least another moiety in the helical region responsible for cell adhesion. The results with these peptides revealed to some extent how corneal epithelial cells react at the molecular level with type IV collagen. They could serve as the basis for therapeutic agents to modify corneal epithelial behavior in situations of perturbed wound healing.