Molecular cloning of MDA5, phylogenetic analysis of RIG‐I‐like receptors (RLRs) and differential gene expression of RLRs, interferons and proinflammatory cytokines after in vitro challenge with IPNV, ISAV and SAV in the salmonid cell line TO

Abstract

The RIG-I receptors RIG-I, MDA5 and LGP2 are involved in viral recognition, and they have different ligand specificity and recognize different viruses. Activation of RIG-I-like receptors (RLRs) leads to production of cytokines essential for antiviral immunity. In fish, most research has focused on interferons, and less is known about the production of proinflammatory cytokines during viral infections. In this study, we have cloned the full-length MDA5 sequence in Atlantic salmon, and compared it with RIG-I and LGP2. Further, the salmonid cell line TO was infected with three fish pathogenic viruses, infectious pancreatic necrosis virus (IPNV), infectious salmon anaemia virus (ISAV) and salmonid alphavirus (SAV), and differential gene expression (DEG) analyses of RLRs, interferons (IFNa-d) and proinflammatory cytokines (TNF-α1, TNF-α2, IL-1β, IL-6, IL-12 p40s) were performed. The DEG analyses showed that the responses of proinflammatory cytokines in TO cells infected with IPNV and ISAV were profoundly different from SAV-infected cells. In the two aforementioned, TNF-α1 and TNF-α2 were highly upregulated, while in SAV-infected cells these cytokines were downregulated. Knowledge of virus recognition by the host and the immune responses during infection may help elucidate why and how some viruses can escape the immune system. Such knowledge is useful for the development of immune prophylactic measures.

Addressing viral and bacterial threats to salmon farming in Chile: historical contexts and perspectives for management and control

“…Comparative analyses of differentially expressed genes for RIG-I-like receptors, interferons (INFa-d) and pro-inflammatory cytokines (TNF-a1, TNF-a2, IL-1b, IL-6, IL-12 and p40s) in the TO cell line infected with different salmonid viruses revealed that proinflammatory cytokine responses in cell lines infected with IPNv and ISAv were proudly different from responses in cells infected by the salmonid alphavirus. In cases of IPNv and ISAv infections, TNF-a1 and TNF-a2 were positively regulated, whereas cells infected with the salmonid alphavirus evidenced a negative regulation of these transferons (Nerbøvik et al 2017).…”

“…In cases of IPNv and ISAv infections, TNF‐α1 and TNF‐α2 were positively regulated, whereas cells infected with the salmonid alphavirus evidenced a negative regulation of these transferons (Nerbøvik et al . ).…”

Potential Therapies for Infectious Diseases Based on Targeting Immune Evasion Mechanisms That Pathogens Have in Common With Cancer Cells

“…Immune surveillance of viral pathogens is largely accomplished via intracellular sensors that detect viral RNA and DNA (Ma and Damania, 2016; Roy et al, 2016; Nerbøvik et al, 2017). Viruses can suppress the immune response by interfering with antiviral signaling pathways, particularly by modifying their nucleic acids, inhibiting proper expression of PRRs and their adaptors (Chan and Gack, 2016), and suppressing the production of antiviral cytokines (Zou et al, 2016).…”

Dual RNA-Seq Unveils Pseudomonas plecoglossicida htpG Gene Functions During Host-Pathogen Interactions With Epinephelus coioides

“…Interleukins (ILs) are the largest group of cytokines and play crucial roles in host innate/acquired immune response (49). To date, more than 30 ILs have been identified in fish (50). IL-6 as a key member of cytokines plays key roles in immune process, including acute phase response, hematopoiesis, energy sensor, and immune cell differentiation through modulating immune-signaling pathways (51, 52).…”