Secreted peptides from sea anemones are of interest as novel therapeutic leads for the treatment of autoimmune, as well as other, diseases. One such peptide is proving successful in clinical trials as the basis of a drug to treat psoriasis.1 Despite the growing interest in sea anemone peptides, there is a lack of knowledge regarding those found in endemic Australian species. Moreover, little is known regarding the distribution of peptides in discrete morphological regions of sea anemones, and the correlation, if any, between distribution and bioactivity of those peptides.
Pharmacologically active peptides are located in the venom of sea anemones, which is contained in microscopic organelles known as cnidae. Cnidae are distributed throughout the ectodermal tissue, and each type of cnidae performs a specific biological function: prey capture, aggression or adherence. In turn, each discrete morphological region of a sea anemone, e.g. tentacles, acrorhagi and actinopharynx (throat), has a unique complement of cnidae. We hypothesised that significant morphological regions may have a unique peptide profile owing to the cnidae contained therein and the biological function associated with each region.
Initial proof-of-concept peptidomics, using whole tissue preparations for five discrete morphological regions of Oulactis sp., showed that each region has a unique peptide profile. Using MALDI-IMS we examined the same Regions of Interest (ROI’s) in Oulactis muscosa. Average spectra for each ROI were again shown to be unique. Imaging allowed us to examine individual masses from ROI’s; some peptide masses were found ubiquitously throughout the tissue, whilst others were restricted to discrete ROI’s.2 MALDI-IMS data has allowed us to infer biological function of peptides based on tissue distribution, whilst providing us with new regions of interest to examine for their venom components in conjunction with transcriptomics/peptidomics.