Interplay of bacteria and host-derived bioactive peptides in microbe host interaction

01.01.2014 bis 31.12.2016

Keratinocytes in the epidermal layer of skin actively participate in the innate immune response by production of several cytokines and chemokines able to attract immune cells into the skin and antimicrobial peptides or proteins (AMPs). Skin-colonizing bacteria are constantly exposed to host peptides such as defensins and chemokines, which combine proinflammatory and antimicrobial properties. In parallel, skin-colonizing bacteria are known to be a rich source of bioactive peptides most of which have hardly been studied in the context of colonization and infection. The peptides include antibacterial bacteriocins whose potential immunomodulatory properties have never been analyzed. The recent discovery by our and other groups that host and bacteria-derived peptides can cooperate raises the question of how such synergisms or antagonisms may affect immune reactions during bacterial colonization and infection. We assume that synergistic and or antagonistic activities between bacterial and host peptides is a common phenomenon that warrants a detailed study to better understand the complex interplay of microbes and host. Starting from our long-standing expertise and collaboration in antimicrobial peptides we plan to study how the various host and bacterial peptides affect each other in killing bacteria and in influencing keratinocytes and immune cells. Studies on ligand/receptor interaction and on subsequent signal transduction events will help to obtain a clear picture of molecular events that may help to clarify why skin infectious disorders can develop. Our studies should pave the way for utilizing bioactive peptides in immunomodulatory antiinfective therapies.