Characterization of host factors associated with the internal ribosomal entry sites of foot-and-mouth disease and classical swine fever viruses

Abstract

Foot-and-mouth disease virus (FMDV) and classical swine fever virus (CSFV) possess positive-sense single-stranded RNA genomes and an internal ribosomal entry site (IRES) element within their 5′-untranslated regions. To investigate the common host factors associated with these IRESs, we established cell lines expressing a bicistronic luciferase reporter plasmid containing an FMDV-IRES or CSFV-IRES element between the Renilla and firefly luciferase genes. First, we treated FMDV-IRES cells with the French maritime pine extract, Pycnogenol (PYC), and examined its suppressive effect on FMDV-IRES activity, as PYC has been reported to have antiviral properties. Next, we performed microarray analysis to identify the host factors that modified their expression upon treatment with PYC, and confirmed their function using specific siRNAs. We found that polycystic kidney disease 1-like 3 (PKD1L3) and ubiquitin-specific peptidase 31 (USP31) were associated with FMDV-IRES activity. Moreover, silencing of these factors significantly suppressed CSFV-IRES activity. Thus, PKD1L3 and USP31 are host factors associated with the functions of FMDV- and CSFV-IRES elements.

Suppression of dengue virus replication by the French maritime pine extract Pycnogenol®

“…We previously performed a comprehensive characterization of host factors whose gene expression was modified in response to PYC treatment, using microarray analysis ( Ide et al., 2022 ). The greatest suppression was observed for lnc-IFI44-2 , followed by Pkd1l3 and Usp31 ( Fig.…”

“…5 A, Online Resource 1). siRNAs targeting these genes suppress FMDV-IRES and CSFV-IRES activity ( Ide et al., 2022 ). Therefore, we designed siRNAs targeting these genes, to treat DENV2-infected cells.…”

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Fig 5 Microarray analysis results, and gene silencing using siRNAs. ( A ) Fold changes in lnc-IFI44-2, PKD1l3 , and USP31 gene expression are indicated ( Ide et al., 2022 ). ( B ) siRNAs targeting lnc-IFI44-2, PKD1l3 , and USP31 were transfected into HuH-7 cells challenged with DENV2.

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“…RNA was isolated from PYC-treated cells and microarray analysis was performed as previously described ( Ide et al., 2022 ). The most significantly or commonly suppressed internal ribosomal entry sites (IRESs) were selected, and their siRNAs were designed using BLOCK-iT RNAi Designer (Thermo Fisher Scientific, Waltham, MA, USA).…”

“…We have previously described the antiviral effect of the French maritime pine extract, pycnogenol® (PYC), both in vitro and in vivo . PYC improves the efficacy of antiviral agents against hepatitis C virus ( Ezzikouri et al., 2015 ) and inhibits the replication of classical swine fever virus ( Ide et al., 2022 ). It is a natural product used as a health food by humans (American Botanical Council, 2010 ).…”