Collective Migration of Keratinocytes during Wound Healing
Fengrong Wang, Song Chen, Hans B. Liu, Carole A. Parent and Pierre A. Coulombe*, Keratins 6a/6b Regulate Keratinocyte Migration by Impacting Cell-cell and Cell-matrix Adhesion, J. Cell Biol 2018 217: jcb.201712130
After injury, the skin and the tissues under it are able to repair themselves. This process, termed as wound healing, is extremely complicated. It involves various cellular and noncellular elements. Over 90% of the epidermis, which is the outermost layer of the skin, consists of keratinocytes. They serve as a barrier to prevent the invasion of pathogenic bacteria, fungi, and other microorganisms. Upon injury, survived keratinocytes suspend terminal differentiation and undergo dramatic changes to prepare for migration to close the wound. These changes not only include changes in cell shape and size, but also the composition of keratin intermediate filaments. The previous studies have shown that the expression of a type II intermediate filament, keratin 6, is rapidly induced at the injury site, suggesting that keratin 6 has an import role during tissue repair. Although the mice without both isoforms of keratin 6 die during the first week of life, the keratinocytes from the newborn mice skin exhibit an enhanced migration ability compared with ones from wild type mice. This finding indicates that the induction of keratin 6 in the keratinocytes near injury site attenuates their migration potential. To understand the mechanism behind this phenomena, we carefully evaluated the cell-cell and cell-matrix adhesion during keratinocyte collective migration and found that the induction of keratin 6 may be critical to regulate the balance of cell-cell and cell-matrix adhesion to promote efficient collective migration and wound closure.