The role of keratinocytes in inflammation

The epidermis is the external layer of the skin and is composed mainly of keratinocytes. Therefore, keratinocytes play an indispensable role as inherent constituents of the skin barrier in physical defenses against environmental threats. Keratinocytes also exert an active protective role against invasion by pathogens. This competency is of particular importance when physical defenses fail as a consequence of skin injury. During the inflammatory phase of healing, keratinocytes act as immuno-modulators, managing inflammation via a rigorously coordinated network of inflammatory cascades, triggered by keratinocyte-receptor communication with the surroundings in a paracrine and autocrine manner. This review summarizes current understandings of the coordinated inflammatory network and focuses on recent progress regarding the role of keratinocytes in early phases of skin wound healing.