Antimicrobial peptides in the gut-brain axis: A straightforward review to unravel some missing links

Antimicrobial peptides (AMPs) are intriguing molecules, able to directly kill several microorganisms and to regulate multiple aspects of the immune response. Despite the extensive studies on the role of AMPs in the epithelial barrier, placing them as a pivotal line of defense against pathogen invasion, little attention has been directed to their role in the maintenance and modulation of the gut microbiota and, by consequence, of the homeostasis of extra intestinal tissues. Here, we review the recent literature about the microbiome-gut-brain axis, focusing on the role of AMPs in this scenario. We provide a straightforward revision of current data in order to provide an overview of the subject, discussing more in depth some points that, in our opinion, are crucial and have received little attention.