Abortive Infection of Snakehead Fish Vesiculovirus in ZF4 Cells Was Associated with the RLRs Pathway Activation by Viral Replicative Intermediates

Abstract

Snakehead fish vesiculovirus (SHVV) is a negative strand RNA virus which can cause great economic losses in fish culture. To facilitate the study of SHVV-host interactions, the susceptibility of zebrafish embryonic fibroblast cell line (ZF4) to the SHVV was investigated in this report. The results showed that high amount of viral mRNAs and cRNAs were detected at the 3 h post-infection. However, the expressions of the viral mRNAs and cRNA were decreased dramatically after 6 h post-infection. In addition, the expressions of interferon (IFN) and interferon-induced GTP-binding protein Mx were all up regulated significantly at the late stage of the infection. Meanwhile, the expressions of Retinoic acid-inducible gene I (RIG-I) and Melanoma differentiation-associated gene 5 (MDA5) were also all up-regulated significantly during the infection. Two isoforms of DrLGP2 from zebrafish were also cloned and analyzed. Interestingly, the expression of DrLGP2a but not DrLGP2b was significantly up-regulated at both mRNA and protein levels, indicating that the two DrLGP2 isoforms might play different roles during the SHVV infection. Transfection experiment showed that viral replicative intermediates were required for the activation of IFN-α expression. Taken together, the abortive infection of SHVV in ZF4 cells was associated with the activation of RLRs pathway, which was activated by viral replicative intermediates.

Beta-glucan enhances the response to SVCV infection in zebrafish

“…The cells used in this work were zebrafish embryonic fibroblast ZF4 cells (Wang, 2015) purchased from the American Type Culture Collection (ATCC number CRL-2050). The cells were maintained under RPMI-1640 Dutch modified culture medium (Gibco, Invitrogen Corporation, UK) at 28ºC in a 5% CO 2 containing 10% fetal calf serum (Sigma, St Louis, USA), 1mM pyruvate, 2mM glutamine, 50µg/mL gentamicin and 2µg/mL fungizone.…”

“…Disease caused by SVCV is a threat to carp and other cyprinid species in aquaculture industry. Adult zebrafish (Danio rerio) is susceptible to SVCV infection, showing clinical signs and experiencing mortality (Encinas, 2013;Sanders, 2003).The availability of the whole genome sequence as well as established cell lines susceptible to viral infection (Wang, 2015) have made zebrafish, also a cyprinid fish, an attractive experimental model for studies of infectious disease and immunity in teleosts (Varela, 2017).…”

Pattern recognition receptors in zebrafish provide functional and evolutionary insight into innate immune signaling pathways

“…86, 87 Because this molecule has both inhibitory and stimulatory effects, the role of LGP2 in the innate antiviral response is still unclear in fish as well as in mammals. Zebrafish LGP2 has a domain structure similar to zMDA5.…”

Retinoic acid‐inducible gene I (RIG‐I)‐like receptors (RLRs) in fish: current knowledge and future perspectives

“…Induction of RLR family members was observed in ZF4 cells infected with three kinds of single‐stranded RNA (ssRNA) viruses, i.e. snakehead fish vesiculovirus, nervous necrosis virus and spring viraemia of carp virus (SVCV), except that LGP2 has not been studied in SVCV‐infected cells . In grass carp, RIG‐I, MDA5 and LGP2 were induced in vivo at mRNA level in several tissues or organs when healthy fish were challenged with a dsRNA viral pathogen, the grass carp reovirus .…”