Bidimensional analysis of desmoglein 1 distribution on the outermost corneocytes provides the structural and functional information of the stratum corneum

BackgroundThe stratum corneum (SC) plays an important role in cutaneous barrier function. Recent clarification of the pathophysiology of several keratoses has suggested that adhesive molecules contribute not only to SC construction but also to SC barrier function.ObjectiveThe purpose of this study is to clarify how the distribution of adhesion molecules on corneocytes contributes to the construction of the SC and the overall organization and function of the cutaneous barrier.MethodsTo investigate the distribution of desmoglein 1 (Dsg1), which may be a main component of corneodesmosomes (CDSs) in the SC, we used a bidimensional observation method using tape-stripped corneocytes and several immunohistochemical techniques to demonstrate the distribution of Dsg1 and to deduce internal events in the SC.ResultsImmunofluorescence labeling showed that Dsg1 distributed on corneocytes of the outermost SC with a characteristic pattern at the periphery, or over the entire surface, and differences in this distribution pattern correlated with the transepidermal water loss (TEWL). Furthermore, electron microscopic analysis showed that (1) Dsg1 was localized on CDSs involved in adhesion, and (2) CDSs on the periphery of corneocytes contributed to the generation of the characteristic basket-weave structure.ConclusionWe explored the distribution pattern of Dsg1 in the SC via a non-invasive investigation tool. Our findings indicate the significance of adhesion molecules in the formation and function of the SC, and suggest that adhesion molecules are one of the important elements in barrier formation in addition to corneocytes, which act as bricks, and intercellular lipids, which act as mortar.