Innate Immune Responses of a Scleractinian Coral to Vibriosis

• Published in: The Journal of biological chemistry Vol. 286; no. 25; pp. 22688 - 22698
• Main Authors: Vidal-Dupiol, Jeremie, Ladrière, Ophélie, Destoumieux-Garzón, Delphine, Sautière, Pierre-Eric, Meistertzheim, Anne-Leila, Tambutté, Eric, Tambutté, Sylvie, Duval, David, Fouré, Laurent, Adjeroud, Mehdi, Mitta, Guillaume
• Format: Journal Article Web Resource
• Language: English
• Published: United States Elsevier Inc 24-06-2011; American Society for Biochemistry and Molecular Biology
• Subjects: Amino Acid Sequence; Animals; Anthozoa - genetics; Anthozoa - immunology; Anthozoa - metabolism; Anthozoa - microbiology; Antimicrobial Cationic Peptides - chemistry; Antimicrobial Cationic Peptides - genetics; Antimicrobial Cationic Peptides - metabolism; Antimicrobial Cationic Peptides - pharmacology; Antimicrobial Peptides; Aquatic sciences & oceanology; Bacteria; Bacterial Toxins - chemistry; Base Sequence; Cnidaria; Defensins; Disulfides - chemistry; Earth Sciences; Gene Expression Regulation; Host-Vibrio Interaction; Immunity, Innate; Immunology; Innate Immunity; Invertebrate Species; Life Sciences; Microbiology; Molecular Sequence Data; Oceanography; Protein Transport; Sciences aquatiques & océanologie; Sciences du vivant; Sciences of the Universe; Vibrio - drug effects; Vibrio - pathogenicity; Vibrio - physiology; Immunology; Defensins; Microbiology; Invertebrate Species; Innate Immunity; Cnidaria; Host-Vibrio Interaction; Bacteria; Antimicrobial Peptides
• ISSN: 0021-9258; 1083-351X; 1083-351X
• DOI: 10.1074/jbc.M110.216358

Scleractinian corals are the most basal eumetazoan taxon and provide the biological and physical framework for coral reefs, which are among the most diverse of all ecosystems. Over the past three decades and coincident with climate change, these phototrophic symbiotic organisms have been subject to increasingly frequent and severe diseases, which are now geographically widespread and a major threat to these ecosystems. Although coral immunity has been the subject of increasing study, the available information remains fragmentary, especially with respect to coral antimicrobial responses. In this study, we characterized damicornin from Pocillopora damicornis, the first scleractinian antimicrobial peptide (AMP) to be reported. We found that its precursor has a segmented organization comprising a signal peptide, an acidic proregion, and the C-terminal AMP. The 40-residue AMP is cationic, C-terminally amidated, and characterized by the presence of six cysteine molecules joined by three intramolecular disulfide bridges. Its cysteine array is common to another AMP and toxins from cnidarians; this suggests a common ancestor, as has been proposed for AMPs and toxins from arthropods. Damicornin was active in vitro against Gram-positive bacteria and the fungus Fusarium oxysporum. Damicornin expression was studied using a combination of immunohistochemistry, reverse phase HPLC, and quantitative RT-PCR. Our data show that damicornin is constitutively transcribed in ectodermal granular cells, where it is stored, and further released in response to nonpathogenic immune challenge. Damicornin gene expression was repressed by the coral pathogen Vibrio coralliilyticus. This is the first evidence of AMP gene repression in a host-Vibrio interaction.