Integrin α3β1 inhibits directional migration and wound re-epithelialization in the skin

Abstract

Re-epithelialization after skin wounding requires both migration and hyperproliferation of keratinocytes. Laminin-332 is deposited during migration over the provisional matrix. To investigate the function of the laminin-332 binding integrin α3α1 in wound re-epithelialization, we generated Itga3flox/flox; K14-Cre mice lacking the α3 subunit specifically in the basal layer of the epidermis. These mice are viable but display several skin defects, including local inflammation, hair loss, basement membrane duplication and microblistering at the dermal-epidermal junction, whereas hemidesmosome assembly and keratinocyte differentiation are not impaired. Wound healing is slightly faster in the absence of integrin α3α1, whereas proliferation, the distribution of other integrins and the deposition of basement membrane proteins in the wound bed are unaltered. In vitro, cell spreading is rescued by increased surface expression of α6α1 integrin in the absence of integrin α3. The α3-deficient keratinocytes migrate with an increased velocity and persistence, whereas proliferation, growth factor signaling, hemidesmosome assembly, and laminin-332 deposition appeared to be normal. We suggest that integrin α3β1 delays keratinocyte migration during wound re-epithelialization, by binding to the laminin-332 that is newly deposited on the wound bed.