Involvement of Periostin in Skin Function and the Pathogenesis of Skin Diseases.

Skin is a large organ that is susceptible to damage by external forces, chronic inflammation, and autoimmune reactions. In general, tissue damage causes alterations in both the configuration and type of cells in lesional skin. This phenomenon, called tissue remodeling, is a universal biological response elicited by programmed cell death, inflammation, immune disorders, and tumorigenic, tumor proliferative, and cytoreductive activity. During this process, changes in the components that comprise the extracellular matrix are required to provide an environment that facilitates tissue remodeling. Among these extracellular matrix components, periostin (a glycoprotein secreted predominantly by dermal fibroblasts) has attracted much attention. In normal skin, periostin localizes mainly in the papillary dermis and basement membrane of the epidermis. However, it is expressed at higher levels in the dermis of lesional skin of those with atopic dermatitis, scars, systemic/limited scleroderma, melanoma, and cutaneous T cell lymphoma; expression is also increased by damage caused by allergic/autoimmune responses. Furthermore, periostin induces processes that result in development of dermal fibrosis; it also activates or protracts the immune response. The aim of this review is to summarize recent knowledge about the role of periostin in the pathogenesis of dermatoses.