Cold Exposure-Induced Up-Regulation of Hsp70 Positively Regulates PEDV mRNA Synthesis and Protein Expression In Vitro

Abstract

Porcine epidemic diarrhea (PED) is a highly contagious, intestinal infectious disease caused by porcine epidemic diarrhea virus (PEDV). PEDV as an emerging and re-emerging epizootic virus of swine causes substantial economic losses to the pig industry in China and other countries. In China, the occurrence of PED shows significant seasonal variations, usually outbreak during the winter season. The epidemic characteristics of PED may be highly correlated with the changes of ambient temperature. However, molecular mechanism on the seasonal occurrence of PED still remains unclear. It has been widely observed that low ambient temperature up-regulates the expression of host heat shock protein 70 (Hsp70). Here, we showed that nucleotide and protein levels of Hsp70 were up-regulated in the intestinal of cold exposed pig and cold exposed Vero E6 cells. We found that overexpression of Hsp70 could increase PEDV mRNA synthesis and protein expression in Vero E6 and IPEC-J2 cells, while the siRNAs mediated knockdown of Hsp70 and VER155008 mediated inhibition of Hsp70 resulted in inhibition of viral mRNA synthesis and protein expression in Vero E6 cells. These data suggested that Hsp70 positively regulated PEDV mRNA synthesis and protein expression, which being helpful for understanding the seasonality of PED epidemics and development of novel antiviral therapies in the future.

Estimated quantity of swine virus genomes based on quantitative PCR analysis in spray-dried porcine plasma samples collected from multiple manufacturing plants

“…Although the present study was not designed to elucidate seasonal differences in the estimated quantity for PEDV genome in the different parts of the world, the results suggest a higher frequency of detection and viral loads during the winter, while it was lower in summertime ( S1 and S2 Tables). These results are consistent with the observation that PEDV is more stable in cold environments [ 50 ] and has a lower incidence of clinical diarrhea cases at farms during the summer season [ 51 ].…”

Heat shock protein 70 could enhance porcine epidemic diarrhoea virus replication by interacting with membrane proteins

“…They concluded that HSP70 positively regulated PEDV mRNA synthesis and protein expression. These results are similar to our results in the correlation between HSP70 and PEDV replication [ 39 ].…”

Estimated quantity of swine virus genomes based on quantitative PCR analysis in spray-dried porcine plasma samples collected from multiple manufacturing plants

“…Although the present study was not designed to elucidate seasonal differences in the estimated quantity for PEDV genome in the different parts of the world, obtained results suggest higher frequency of detection and viral loads during the winter, while it was lower in summertime (S1 and S2 Tables). These results are in line with the fact that PEDV is more stable in cold environments [50] and has lower incidence of clinical diarrhea cases at farms during the summer season [51].…”