Cryptoporus volvatus Extract Inhibits Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) In Vitro and In Vivo

Abstract

Porcine reproductive and respiratory syndrome virus (PRRSV) is an important arterivirus that can cause significant losses in swine industry. At present, there are no adequate control strategies against PRRSV. Thus, there is an urgent need for new treatment regimens that have efficacious antiviral activity to compensate for vaccines. Cryptoporus volvatus commonly serves as an anti-infective agent in Tradational Chinese Medicines. In this report, we exploited whether the aqueous extract from the fruiting body of Cryptoporus volvatus had the potential to inhibit PRRSV infection. Our results showed that the extract significantly inhibited PRRSV infection by repressing virus entry, viral RNA expression, and possibly viral protein synthesis, cell-to-cell spread, and releasing of virus particles. However, it did not block PRRSV binding to cells. Further studies confirmed that the extract directly inhibited PRRSV RNA-dependent RNA polymerase (RdRp) activity, thus interfering with PRRSV RNA and protein synthesis. More importantly, the extract efficiently inhibited highly pathologic PRRSV (HP-PRRSV) infection in vivo, reduced virus load in serum, and increased the survival rate of pigs inoculated with HP-PRRSV strain. Collectively, our findings imply that the aqueous extract from the fruiting body of Cryptoporus volvatus has the potential to be used for anti-PRRSV therapies.

Effects of Armillariella tabescens mycelia on the growth performance and intestinal immune response and microflora of early‐weaned pigs

“…Similarly, administration of Shiitake mushroom‐extracted lentinan and fermentation products of S. cerevisiae have been shown to have an inhibitory effect on E. coli in the small intestine of piglets (van Nevel et al ). In addition, the levels of Streptococci in the intestinal lumen, porcine reproductive and respiratory syndrome virus in the serum, and porcine circovirus in lymphoid tissues, were significantly decreased after piglets were fed Shiitake mushroom‐extracted lentinan, Cryptoporus volvatus and fermentation products of Ganoderma lucidum , respectively (van Nevel et al ; Chen et al ; Gao et al ).…”

HP-PRRSV is attenuated by de-optimization of codon pair bias in its RNA-dependent RNA polymerase nsp9 gene

“…Cell culture supernatant obtained at 48 h post-transfection was inoculated on primary cultured PAMs and immunofluorescence assay was performed for virus detection as described previously (Fig. S1) (Gao et al, 2013). Briefly, cells were fixed with cold methanol-acetone (1:1) for 10 min at 4 1C, washed with phosphate-buffered saline (PBS), and then blocked with 5% normal goat serum for 30 min at room temperature.…”

“…The ORF1a/ORF1b ribosomal frame shift site was removed as described before (Gao et al, 2013). Briefly, nucleotides T-7600 and A-7602 were mutated to C, and a nucleotide C was inserted between A-7604 and C-7605.…”

“…The etiological agent, PRRS virus (PRRSV), is a $15.4 kb positive-sense RNA virus belonging to the family Arteriviridae, the order Nidovirales (Gorbalenya et al, 2006). Comparative genome sequence analysis has revealed that PRRSV has two distinct genotypes, type 1 (European type) and type 2 (North American type) (Benfield et al, 1992;Nelsen et al, 1999).…”

Characterization of polyclonal antibodies against nonstructural protein 9 from the porcine reproductive and respiratory syndrome virus

“…An RT-qPCR based technique was developed which targets the viral RNA-dependent RNA polymerase gene (Nsp9), which is unique to genomic RNA, and has the ability to assess and compare PRRSV replication in a variety of tissues and between divergent strains, including highly pathogenic strains of considerable concern to the global swine industry [14] . A previous study [15] showed that Cryptoporus volvatus extract inhibits the PRRSV RNA and protein synthesis by directly inhibiting PRRSV RdRp activity, which indicates that RdRp can be used as a target protein for drug discovery and antiviral research.…”