Biology subjects

Renault, T.

Publications and source records attributed to Renault, T..

3 recordsLinked to original sources

bioRxiv2025

Dynamic of the transcriptomic landscape of OsHV-1 replication in haemocytes of Pacific oyster

Since the 1990s, the Pacific oyster (Magallana gigas) has experienced repeated mortality events associated with Ostreid herpesvirus 1 (OsHV-1). Although the virus has been genomically characterised, its replication cycle and its interactions with the oyster immune system are still not well understood. In particular, little is known about the dynamics of OsHV-1 gene expression and the immune responses of haemocytes from oysters with varying susceptibility to the virus. While some studies have focused on the expression of specific viral and host genes on whole oysters, none have provided a comprehensive analysis of genomes-wide expression across multiple post-infection time points in haemocytes. The lack of oyster cell lines makes studying virus-host interactions in vitro challenging. However, haemocytes, the key immune cells circulating in hemolymph, can be maintained in vitro in the short term and represent a relevant model for analyzing infection dynamics. In this study, haemocytes from two M. gigas families, one highly susceptible and one less susceptible to OsHV-1, were infected in vitro. We tracked the viral and host transcriptomes over a 24-hour period post-infection using high-throughput dual transcriptomics. Our results provide a detailed overview of the OsHV-1 transcriptomic landscape in haemocytes from high and low susceptible M. gigas over time. In addition, WGCNA analysis of host genes expression provided insights into the haemocytes response to infection, and highlighted family-specific immune responses. This comprehensive transcriptomic study is the first to describe virus-host interactions across multiple stages of infection in haemocytes from Pacific oysters showing contrasted survival when exposed to OsHV-1. IMPORTANCEThis study provides valuable insights into the interaction between M. gigas and OsHV-1 by analyzing viral expression and host immune response at the cellular level. By focusing on haemocytes, the key immune cells in Pacific oysters, the results reveal a link between host genotype and viral transcriptomic activity, providing new perspectives on molecular basis of natural susceptibility levels to OsHV-1 infection depending of the genetic background. Overall, our findings deepen the understanding of OsHV-1 gene expression dynamics and antiviral defense mechanisms in key species cultivated worldwide.

bioinformatics↗

bioRxiv2023

Antiviral protection in the Pacific oyster Crassostrea (Magallana) gigas against OsHV-1 infection using UV-inactivated virus

The increase of the frequency and severity of marine diseases affecting farmed marine mollusks are currently threatening the sustainability of this aquaculture sector, with few available prophylactic or therapeutic solutions. Recent advances have shown that the innate immune system of invertebrates can develop memory mechanisms allowing for efficient protection against pathogens. These properties have been called innate immune memory, immune priming or trained immunity. Previous results demonstrated the possibility to elicit antiviral immune priming to protect Pacific oysters against the ostreid herpes virus 1 (OsHV-1), currently plaguing M. gigas production worldwide. Here, we demonstrate that UV-inactivated OsHV-1 is also a potent elicitor of immune priming. Previous exposure to the inactivated virus was able to efficiently protect oysters against OsHV-1, significantly increasing oyster survival. We demonstrate that this exposure blocked viral replication and was able to induce antiviral gene expression potentially involved in controlling the infection. Finally, we show that this phenomenon can persist for at least 3 months, suggesting the induction of innate immune memory mechanisms. This study unravels new ways to train the Pacific oyster immune system that could represent an opportunity to develop new prophylactic strategies to improve health and to sustain the development of marine mollusk aquaculture.

immunology↗

bioRxiv2023

Genetic differentiation and host specialization among OsHV-1 infecting two oyster species in France

AbstractCross-species transmission is a major driver of disease emergence in humans and animals. The Ostreavirus ostreidmalaco1 (OsHV-1) is mainly associated with mortality in the Pacific oyster Magallana gigas, but has also been found in other mollusks, including the European flat oyster Ostrea edulis. This raises questions about OsHV-1 host specificity. This study explored the genetic differentiation of OsHV-1 in M. gigas and O. edulis and the underlying mechanisms. Using high-throughput sequencing, 40 OsHV-1 genomes were obtained from both O. edulis and M. gigas and were analyzed to assess viral diversity, lineage isolation, and cross-species transmission. Comparative genomics, population genetics, phylogenetic and phylodynamic methods revealed that host species significantly influence viral genetic structure. The data suggest that OsHV-1 was introduced in Europe with M. gigas, followed by a cross-species transmission event and divergence into two distinct lineages. Selection signals were identified in genomic regions involved in key viral functions, including host binding, DNA replication, and membrane-associated proteins, indicating possible adaptation to different hosts. Future research should investigate coevolution between OsHV-1 and a broader range of host species using phylogenetic approaches to better understand host-virus dynamics.

evolutionary biology↗