2016 Volume 62 Issue 2 Pages 120-131
In addition to functioning as a physical barrier, the skin has evolved several innate defense mechanisms for the rapid recognition of and protection against harmful microorganisms. As a part of this process, the skin releases a vast and powerful arsenal of antimicrobial peptides/proteins (AMPs), also called host defense peptides/proteins (HDPs), which are key players in the cutaneous immune system. Although originally named antimicrobial peptides, recent evidence has demonstrated that AMPs/HDPs play additional roles in orchestrating the adaptive immune response, such as the regulation of inflammation, induction of cell proliferation and differentiation, regulation of cytokine/chemokine production, facilitation of cell migration, promotion of wound healing and regulation of tight junction barriers. Additionally, numerous skin diseases show altered expression of AMPs/HDPs in the lesional skin, suggesting the crucial roles of these molecules in the pathophysiology of skin diseases. The purpose of this review is to describe the current knowledge regarding some of the most common and well-known AMPs/HDPs derived from the skin, to discuss the regulation of their expression and their antimicrobial and immunomodulatory functions, and to outline their roles in various skin diseases. We believe that understanding the basic knowledge of skin-derived AMPs/HDPs would provide new insight into the pathophysiology of skin disorders and offer novel therapeutic opportunities for skin infectious diseases.