Acute cutaneous barrier disruption activates epidermal p44/42 and p38 mitogen-activated protein kinases in human and hairless guinea pig skin

Acute cutaneous barrier disruption of the skin elicits various homeostatic repair responses in the epidermis. Although several candidates for the signaling mechanisms that induce these responses have been reported, e.g. the calcium and ion concentration, peroxisome proliferator-activated receptor-alpha, and TNF-alpha signaling mediated by sphingomyelinases, the exact nature of the signals remains undertermined. Therefore, assuming that an important group of serine/threonine-signaling kinases, mitogen- and SAPK/JNK, might link the barrier disruption to the subsequent homeostatic responses, the activation of three MAPKs in hairless guinea pig or in human skin after barrier disruption was investigated. The epidermal barrier was insulated with tape stripping or organic solvents, and Western blotting, and immune complex kinase assay. In the skin of hairless guinea pigs, p44/42 MAPK and p38 MAPK, but nor SAPK/JNK, were continued to be activated for at least 180 min. The activation of p44/42 which positively correlated with the number of tape strippings, whereas K+ sucrose solution suppressed its activation. The activation of p44/42 MAPK was also induced by treatment of the skin with organic solvents. In similar fashion, p44/42 and p38 MAPKs were found to be activated in human skin after tape stripping. These results for strongly suggest that the activation of p44/42 and p38 MAPKs links the stimuli of barrier disruption to the subsequent homeostatic responses to repair the barrier defect.