Antimicrobial peptides: old molecules with new ideas

Abstract

Almost 90 years have passed since Alexander Fleming discovered the antimicrobial activity of lysozyme, the first natural antibiotic isolated from our body. Since then, various types of molecules with antibiotic activity have been isolated from animals, insects, plants, and bacteria, and their use has revolutionized clinical medicine. So far, more than 1,200 types of peptides with antimicrobial activity have been isolated from various cells and tissues, and it appears that all living organisms use these antimicrobial peptides (AMPs) in their host defense. In the past decade, innate AMPs produced by mammals have been shown to be essential for the protection of skin and other organs. Their importance is because of their pleiotrophic functions to not only kill microbes but also control host physiological functions such as inflammation, angiogenesis, and wound healing. Recent advances in our understanding of the function of AMPs have associated their altered production with various human diseases such as psoriasis, atopic dermatitis, and rosacea. In this review, we summarize the history of AMP biology and provide an overview of recent research progress in this field.

Figure 1. The layered antimicrobial peptides of human skin

A representative partial list of AMPs produced by skin-residing cells is shown. The composition, location, timing of expression and post-translational processing of AMPs in the skin are all important variables that enable them to serve a wide range of functions in defense of the skin. These functions are not only limited to action as a natural antibiotic shield but also include the capacity to trigger cell recruitment, growth and differentiation. Numbers in parentheses indicate references. ⁽¹⁾, (Ganz et al., 1985; Harder et al., 2001; Johnston et al., 2011); ⁽²⁾, (Frohm et al., 1997); ⁽³⁾, (Harder and Schroder, 2002); ⁽⁴⁾, (Glaser et al., 2005); ⁽⁵⁾, (Cumberbatch et al., 2000); ⁽⁶⁾, (Marchini et al., 2002); ⁽⁷⁾, (Wingens et al., 1998); ⁽⁸⁾, (Meyer-Hoffert et al., 2003); ⁽⁹⁾, (Cutuli et al., 2000; Schauer et al., 1994); ⁽¹⁰⁾, (Radek et al., 2008); ⁽¹¹⁾, (Abtin et al., 2010); ⁽¹²⁾, (Cogen et al., 2010b); ⁽¹³⁾, (Di Nardo et al., 2003); ⁽¹⁴⁾, (Ganz, 2003); ⁽¹⁵⁾, (Agerberth et al., 1995; Cowland et al., 1995); ⁽¹⁶⁾, (Caccavo et al., 2002); ⁽¹⁷⁾, (Belaaouaj et al., 2000); ⁽¹⁸⁾, (Murakami et al., 2004); ⁽¹⁹⁾, (Schittek et al., 2001); ⁽²⁰⁾, (Ali et al., 2001; Oono et al., 2006); ⁽²¹⁾, (Stenger et al., 1998); ⁽²²⁾, (Chronnell et al., 2001; Nagy et al., 2006; Nakatsuji et al., 2010); ⁽²³⁾, (Lee et al., 2009b); ⁽²⁴⁾, (Glaser et al., 2005); ⁽²⁵⁾, (Lee et al., 2008).