Chromogranin A (CHGA) belongs to the granin family of acidic proteins enclosed in secretory vesicles of nervous, endocrine and immune cells. The proteolytic cleveages of specific CHGA sequences by the pro-hormone convertases generate bioactive fragments that exert a broad spectrum of regulatory activities by influencing the endocrine, cardiovascular and immune systems and affect glucose and calcium homeostasis (Helle KB et al. 2007; Aslam R et al. 2012; D'amico MA et al. 2014; Aung G et al. 2011; Tota B et al. 2014).
Several CHGA-derived peptides such as vasostatin-1 (CHGA(19-94) ) and catestatin (CHGA(370-390)) display antimicrobial activities against bacteria, fungi and yeasts (Lugardon K et al. 2000; Briolat J et al. 2005; Radek KA et al. 2008; Aslam R et al. 2013; Shooshtarizadeh P et al. 2010). These peptides are found in biological fluids involved in defence mechanisms (human serum and saliva) and in supernatants of stimulated human neutrophils (Lugardon K et al. 2000; Briolat J et al. 2005). In addition, catestatin (CHGA(370-390) exhibits antimicrobial activity against skin pathogens suggesting a function in cutaneous antimicrobial defense (Radek KA et al. 2008). Biophysical and structural analysis of human catestatin and bovine cateslytin suggests that cationic CHGA-derived peptides interact with anionic phospholipids on the bacterial surface (Sugawara M et al. 2010; Jean-Francois F et al. 2008). However, It remains to be clarified whether catestatin functions as a pore-forming or cell-penetrating agent.