Interactions between virus and vibrio and oyster antiviral response

Impact of tripartite interaction between bacteria, virus and host antiviral response in the C. gigas oyser


Project supported by the scientific direction of  Ifremer (2019-2020)
Coordinators: Caroline Montagnani & Yannick Labreuche
Partners :
Ifremer UMR 8227 Equipe Génomique des vibrios, Station Biologique de Roscoff
Laboratoire Ifremer SG2M La Tremblade


Quorum-sensing (QS) is a cellular signaling mechanism based on the emission by bacteria of mediating molecules called « self-inducers », implicated in intra and inter-specific bacterial communication and coordinating multiple activities in bacteria ( formation of biofilms, bioluminescence, etc …). Recent data have shown that a peptide (cyclo Phe-Pro or cFP) implicated in QS in Vibrio vulnificus bacteria inhibited antiviral response and increased susceptibility of the host to viral infections. This cFP peptide interacts directly with a major receptor of the RIG-1 (RIG-like recognition receptors) antiviral response called RIG-1, thus blocking the interferon’s pathway and antiviral response. These results are particularly original as very little data is currently available (i) on the potential interactions between QS signal molecules and the antiviral response and (ii) more broadly, on the interactions between bacterial microorganisms and viruses in hosts and the impact of these interactions on their susceptibility to disease.
The objective of the CORRUPT project is to explore the impact of virus-bacteria interactions in the Crassostrea gigas oyster in the context of juvenile mortality syndrome. The polymicrobial etiology of this syndrome has recently been decrypted in our laboratory. It is based on a succession of events from a first step of infection and active replication of the OsHV-1 μVar virus, resulting from an inefficient antiviral response of the host, to immunosuppression and secondary infections by opportunistic bacteria, and amongst them vibrios. In this context, we address the question of factors that may influence the antiviral response of the host, promote viral infection and permissiveness to bacterial infections. To answer this question, in light of the data obtained from V. vulnificus, we will study the role of the cFP peptide on the antiviral immune response of the oyster. In addition, the antiviral defense mechanisms decrypted in oysters show the involvement of highly conserved immune pathways, including the interferon pathway and the involvement of RIG-1 receptors. We will therefore look at whether, in the oyster, such interactions between the vibrios QS molecules and the antiviral response receptors may be at the origin of hitherto unknown mechanisms of inhibition of the antiviral system leading to the increase susceptibility of oysters to juvenile mortality syndrome.