Anti-microbial Peptides (AMPs) in Skin Barrier

Abstract

As the name implies, role of anti-microbial peptides (AMPs) has been mainly considered as providing anti-microbial defense against exogenous infections of bacteria, fungi and virus. Through the extensive researches, however, the roles of AMPs are continuously extending; including the regulation of adaptive immune responses and inflammatory responses. In animals, AMPs expression is generally localized in epithelial tissues, such as skin and gastrointestinal tracts. In skin, along with the acid mantle and anti-microbial lipids, epidermal AMPs are responsible for the skin’s anti-microbial barrier function. Recently reported studies have suggested that the AMPs are closely interrelated with other barrier functions exerted by skin, including epidermal permeability barrier function and immune barrier function. While it is still controversial, down-regulated expression of AMPs in atopic dermatitis is, at least in part, responsible for the increased susceptibility of AD skins against secondary infections, usually observed as S. aureus infection. In this review, the brief explanation of AMPs in terms of their structure, function, and regulation of expressions are discussed. In addition, role of AMPs in skin diseases is also explored and the effects of Defensamide™, a recently developed small molecule compound that stimulates the epidermal expression of AMPs, on oxazolone-induced atopic dermatitis animal model is provided. Results of clinical studies performed with Defensamide™ are also introduced.