Effect of a loss of the mda5/ifih1 gene on the antiviral resistance in a Chinook salmon Oncorhynchus tshawytscha cell line

• Published in: PloS one 2024-10, Vol.19 (10), p.e0311283
• Main Authors: Collins, Catherine, Chaumont, Lise, Peruzzi, Mathilde, Jamak, Nedim, Boudinot, Pierre, Béjar, Julia, Moreno, Patricia, Álvarez Torres, Daniel, Collet, Bertrand
• Format: Article
• Language: English
• Subjects: Analysis; Animals; Biological response modifiers; Biology and Life Sciences; Carp; Cell Line; Cells; Chinook salmon; Cloning; CRISPR; CRISPR-Cas Systems; DNA helicase; Double-stranded RNA; Drug resistance; Enzymes; Fish diseases; Fish Diseases - genetics; Fish Diseases - immunology; Fish Diseases - virology; Fish Proteins - genetics; Fish Proteins - metabolism; Fishes; Genes; Genetic aspects; Genome editing; Genomes; Genomics; Health aspects; Infection; Infections; Infectious pancreatic necrosis; Interferon; Interferon Type I - metabolism; Interferon-Induced Helicase, IFIH1 - genetics; Interferon-Induced Helicase, IFIH1 - metabolism; Life Sciences; Maximum likelihood method; Melanoma; Necrosis; Oncorhynchus tshawytscha; Plant virus diseases; Plant viruses; Proteins; Redundancy; Research and Analysis Methods; RNA; Salmon; Salmon - virology; Trout; Viral infections; Viruses
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0311283

Cells are equipped with intracellular RIG-like Receptors (RLRs) detecting double stranded (ds)RNA, a molecule with Pathogen-Associated Molecular Pattern (PAMPs) generated during the life cycle of many viruses. Melanoma Differentiation-Associated protein 5 (MDA5), a helicase enzyme member of the RLRs encoded by the ifih1 gene, binds to long dsRNA molecules during a viral infection and initiates production of type I interferon (IFN1) which orchestrates the antiviral response. In order to understand the contribution of MDA5 to viral resistance in fish cells, we have isolated a clonal Chinook salmon Oncorhynchus tshawytscha epithelial-like cell line invalidated for the ifih1 gene by CRISPR/Cas9 genome editing. We demonstrated that IFN1 induction is impaired in this cell line after infection with the Snakehead Rhabdovirus (SHRV), the Salmon Alphavirus (SAV) or Nervous Necrosis Virus (NNV). The cell line, however, did not show any increase in cytopathic effect when infected with SHRV or SAV. Similarly, no cytopathic effect was observed in the ifih1-/- cell line when infected with Infectious Pancreatic Necrosis Virus (IPNV), Infectious Haemorrhagic Necrotic Virus (IHNV). These results indicate the redundancy of the antiviral innate defence system in CHSE-derived cells, which helps with circumventing viral evasion strategies.