Expression of P-cadherin distinct from that of E-cadherin in re-epithelialization in neonatal rat skin.

Our previous study showed that an open wound made in neonatal rat skin was covered by migration of certain undifferentiated populations of keratinocytes as a multilayered cell sheet. In this study, the expression of the components of adherens junctions (AJ), E- and P-cadherins, and beta-catenin, was examined to understand the underlying mechanisms. Both E- and P-cadherins were downregulated in the basal layer at 6 h post-wounding (PW), indicating a reduction in the intercellular adhesiveness. The expression of P-cadherin but not E-cadherin was expanded to the suprabasal layers at the wound margin at 12 h PW. Moreover, the expression pattern of P-cadherin at sites of cell-cell contact was punctate rather than linear. By 24 h PW, cells accumulated beta-catenin in the cytoplasm in a suprabasal layer contacting the basal layer at the wound margin. Both the E- and P-cadherins showed a punctate AJ pattern at the confined suprabasal layer. Such differential expression of the E- and P-cadherins strongly suggests that these two classic cadherins play distinct roles in re-epithelialization. The changing of the E- and/or P-cadherin expression may participate in a delay of terminal differentiation of keratinocytes for cell supply toward a wound.