Vibrio aestuarianus zinc metalloprotease causes lethality in the Pacific oyster Crassostrea gigas and impairs the host cellular immune defenses

• Published in: Fish & Shellfish Immunology
• Main Authors: Labreuche, Yannick, Le Roux, Frédérique, Henry, Joël, Zatylny-Gaudin, Céline, Huvet, Arnaud, Lambert, Christophe, Soudant, Philippe, Mazel, Didier, Nicolas, Jean-Louis
• Other Authors: Physiologie et Ecophysiologie des Mollusques Marins (PE2M), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS), Unité Lagons, Ecosystèmes et Aquaculture Durable en Nouvelle-Calédonie (LEADNC), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Unité Amélioration génétique, Santé animale et Environnement (AGSAE), Plasticité du Génome Bactérien (PGB), Institut Pasteur Paris (IP)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), This work was supported by the MOREST national project funded by IFREMER and by the Régions Basse-Normandie, Bretagne, Pays de la Loire and Poitou-Charentes and the Conseil Général du Calvados. We thank Patricia Mirella Da Silva and Philippe Miner for technical assistance and helpful discussions during the course of this work.
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2010
• Subjects: Metalloprotease; Hemocytes; Extracellular products; Crassostrea gigas; Oyster; Vibrio aestuarianus; MESH: Amino Acid Sequence; MESH: Analysis of Variance; MESH: Open Reading Frames/genetics; MESH: Ostreidae/drug effects; MESH: Ostreidae/genetics; MESH: Ostreidae/immunology; MESH: Sequence Analysis; DNA; MESH: Vibrio/enzymology; MESH: Animals; MESH: Base Sequence; MESH: DNA Primers/genetics; MESH: Enterotoxins/toxicity; MESH: Extracellular Space/chemistry; MESH: Immunity; Cellular/drug effects; MESH: Metalloendopeptidases/toxicity; MESH: Molecular Sequence Data; [SDE]Environmental Sciences; [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology; Pacific; Pacific oyster
• Online Access: https://hal.univ-brest.fr/hal-00670371; https://doi.org/10.1016/j.fsi.2010.07.007

International audience Extracellular products (ECPs) of the pathogenic Vibrio aestuarianus 01/32 were previously reported to display lethality in Crassostrea gigas oysters and to cause morphological changes and immunosuppression in oyster hemocytes. To identify the source of this toxicity, biochemical and genetic approaches were developed. ECP protease activity and lethality were shown to be significantly reduced following incubation with metal chelators, suggesting the involvement of a zinc metalloprotease. An open reading frame of 1836 bp encoding a 611-aa metalloprotease (designated yam) was identified. The deduced protein sequence showed high homology to other Vibrio metalloproteases reported to be involved in pathogenicity. To further confirm the role of this enzyme in ECP toxicity, a plasmid carrying the yarn gene under the control of an araC-P(BAD) expression cassette was transferred to a Vibrio splendidus related strain, LMC20012(T), previously characterized as non-pathogenic to oysters. Expression of Vam conferred a toxic phenotype to LMG20012(T) ECPs in vivo and cytotoxicity to oyster hemocytes in vitro. Collectively, these data suggest that the Vam metalloprotease is a major contributor to the toxicity induced by V aestuarianus ECPs and is involved in the impairment of oyster hemocyte functions.