MELANOCYTE MOVEMENT IN-VITRO - ROLE OF MATRIX PROTEINS AND INTEGRIN RECEPTORS

During the repigmentation of vitiliginous skin, melanocytes migrate fr om the outer root sheath of the hair follicle into the depigmented ski n. We hypothesize that this requires changes in the local microenviron ment that are conducive to melanocyte migration. One important change in the micro-environment could be the localized production of matrix p roteins. We have previously employed time-lapse photography to evaluat e the effect of inflammatory mediators and cytokines on melanocyte mov ement. We have adapted this system to study the effect of matrix prote ins on melanocyte movement in vitro. Type IV collagen significantly in creases melanocyte migration, whereas laminin and fibronectin have no effect. Cell/matrix interactions are in part controlled by cell-surfac e integrins. Integrins have been demonstrated to be important in contr olling the migration of many cell types. We demonstrate that melanocyt es express cell-membrane alpha2, alpha3, and alpha5 integrins and that the enhanced melanocyte migration on type IV collagen is inhibited by specific function-blocking antibodies to integrins alpha2 and alpha3, but not to alpha5 integrins.