Host derived mechanisms controlling bacterial colonization at the epithelial interface in the basal metazoan Hydra

• Applicant: Professor Dr. Sebastian Fraune
• Subject Area: Evolutionary Cell and Developmental Biology (Zoology)
• Term: from 2012 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 214842927

Epithelia in all animals, which are exposed to the environment, are colonized by diverse communities of microbes. Since Hydra is an early-branching metazoan and has preserved much of the genetic complexity of the common metazoan ancestor it promises to be highly informative to discover evolutionary conserved mechanisms controlling epithelial host-microbe interactions. Previous work has identified receptors, signal transduction cascades and effector molecules involved in epithelial defence. It was shown that the Hydra epithelium actively selects and shapes its microbial community indicating distinct selective pressures imposed on and within the epithelium. Therefore, I hypothesize that a stable bacterial colonization is mainly controlled by host-derived mechanisms. The proposed project will focus on two potential mechanisms maintaining the epithelial host-microbe homeostasis: (i) the influence of the species-specific antimicrobial peptide family arminin on the composition and maintenance of a specific bacterial colonisation and (ii) host derived interference mechanisms with the communication system (quorum sensing) of potential bacterial colonizers (quorum quenching). Together, these insights will unveil ancient mechanisms derived from the in vivo context of a whole epithelial organism controlling epithelial host-microbe homeostasis.

• DFG Programme: Research Grants