Identification of Inhibitory Compounds Against Singapore Grouper Iridovirus Infection by Cell Viability-Based Screening Assay and Droplet Digital PCR

Abstract

Singapore grouper iridovirus (SGIV) is one of the major causative agents of fish diseases and has caused significant economic losses in the aquaculture industry. There is currently no commercial vaccine or effective antiviral treatment against SGIV infection. Annually, an increasing number of small molecule compounds from various sources have been produced, and many are proved to be potential inhibitors against viruses. Here, a high-throughput in vitro cell viability-based screening assay was developed to identify antiviral compounds against SGIV using the luminescent-based CellTiter-Glo reagent in cultured grouper spleen cells by quantificational measurement of the cytopathic effects induced by SGIV infection. This assay was utilized to screen for potential SGIV inhibitors from five customized compounds which had been reported to be capable of inhibiting other viruses and 30 compounds isolated from various marine organisms, and three of them [ribavirin, harringtonine, and 2-hydroxytetradecanoic acid (2-HOM)] were identified to be effective on inhibiting SGIV infection, which was further confirmed with droplet digital PCR (ddPCR). In addition, the ddPCR results revealed that ribavirin and 2-HOM inhibited SGIV replication and entry in a dose-dependent manner, and harringtonine could reduce SGIV replication rather than entry at the working concentration without significant toxicity. These findings provided an easy and reliable cell viability-based screening assay to identify compounds with anti-SGIV effect and a way of studying the anti-SGIV mechanism of compounds.

Cephalotaxine inhibits Zika infection by impeding viral replication and stability

“…Previous studies demonstrated that HT and HHT inhibit replication of CHIKV, VZV [19], and the Sindbis virus (SINV) [28]. HHT has further been shown to exert antiviral effects against coronavirus (CoV) [20] and HBV [16].…”

Palmitic Acid Promotes Virus Replication in Fish Cell by Modulating Autophagy Flux and TBK1-IRF3/7 Pathway

“…Increasing research on lipids in aquaculture had been illuminating. 2-HOM has been characterized as an inhibitor of SGIV that benefits from its interfering with SGIV-ORF088L myristoylation, and resistance against SGIV entry and replication (76). Exploiting specific lipid requirements of pathogens, and delineating the intricate interactions of these pathogens with cellular lipids and the modification of their metabolism, might provide new approaches for antiviral therapies (50).…”

Establishment and characterization of a fin tissue cell line derived from silver pomfret, Pampus argenteus

“…For now, fish cell lines have been established from a variety of different fish species and tissues, which collectively are referred to as the fish invitrome (Bols, Pham, Dayeh, & Lee, ). The fish invitrome is widely used in developing antiviral strategies and comprehending the interaction between virus and the cells of hosts (Jia et al, ; Le et al, ; Zhang et al, ) and non‐hosts (Pham, Lai, Lee, Bols, & Chiou, ). Kim and colleagues reported that VHSV was detected in wild silver pomfret in Korea, indicating silver pomfret was the natural host of VHSV (Kim, Choi, Kim, & Oh, ).…”