HUMAN KERATINOCYTE MIGRATION ON TYPE-IV COLLAGEN - ROLES OF HEPARIN-BINDING SITE AND ALPHA-2-BETA-1 INTEGRIN

BACKGROUND: The migration of human keratinocytes is an early and impor tant event in the reepithelialization of cutaneous wounds. Type IV col lagen, a ubiquitous basement membrane component, promotes keratinocyte migration. EXPERIMENTAL DESIGN: In this study, we sought to identify specific sites within the type IV collagen molecule that induce kerati nocyte locomotion and to characterize the cell surface receptors invol ved. We first examined purified fragments of the type IV collagen mole cule as substrates for keratinocytes in a phagokinetic migration assay . We then tested several synthetic peptides derived from the triple-he lical region of type IV collagen, as well as antibodies against specif ic integrin subunits, for their ability to either support or inhibit k eratinocyte migration on matrices of both type IV collagen and relevan t peptide derivatives. RESULTS: Keratinocytes migrated on the triple-h elical fragment to the same extent as they did on the native type IV c ollagen. The amino-terminal 7S and the carboxy-terminal NC1 regions of type IV collagen failed to support keratinocyte migration. In additio n, Hep III peptide was active both in inhibiting keratinocyte migratio n on type IV collagen and in serving as a substrate matrix for migrati on. Peptide containing the amino acid sequence RGD did not influence c ell migration on type IV collagen. A specific monoclonal antibody agai nst the alpha 2 beta 1 integrin receptor significantly inhibited kerat inocyte migration on matrices of both type IV collagen and Hep III pep tide. CONCLUSIONS: Keratinocyte migration on type IV collagen involves the interaction of the alpha 2 beta 1 receptor with the Hep III regio n of the type IV collagen molecule.