Comparative transcriptomic analysis of porcine epidemic diarrhea virus epidemic and classical strains in IPEC-J2 cells

The effect of asparagine-13 in porcine epidemic diarrhea virus envelope protein on pathogenicity

The pathogenesis of porcine epidemic diarrhea virus (PEDV) has not been fully clarified, which seriously hinders the prevention of the disease. The envelope (E) protein of PEDV induces the expression of pro-inflammatory cytokines, but the role of these inflammatory reactions in PEDV pathogenicity is still unknown. In this study, the asparagine at position 13 was found to be crucial to PEDV E protein induced inflammatory response. Exogenously expressing the parent E protein, rather than the E mutant carrying N13A, induces the activation of NF-κB and expression of inflammatory factors, including IL-6, IL-8, and TNF-α. Compared with the parental rPEDV strain, the recombinant strain rPEDV-EN13A exhibited a significantly lower infectious titer and formed smaller plaques. In addition, rPEDV-EN13A induced lower expression of inflammatory factors in vitro and in vivo. The pathogenicity assay shows that the rPEDV-EN13A strain caused diminished fecal PEDV RNA shedding, delayed death time, and milder histopathological lesions to intestinal villi. Our data provide a unique perspective for exploring the pathogenic mechanism of PEDV and a new target for the development of attenuated PEDV live vaccines.

Rapid on-site diagnosis of PEDV and PoRV co-infection by gold magnetic nanoparticles-based SERS immunochromatography

Porcine epidemic diarrhea virus (PEDV) and porcine rotavirus (PoRV) are the two main pathogens causing porcine diarrhea, which are characterized by high morbidity and mortality. Most of the diagnostic methods available are limited to the laboratory or fail to highlight their advantages in terms of target species, detection time, sensitivity, and stability. To meet the demand for rapid on-site diagnosis of PEDV and PoRV co-infection, a surface-enhanced Raman scattering (SERS) immunochromatographic sensor based on gold magnetic nanoparticles (MNPs) was developed. The sensor is dual-mode, detecting on the basis of color signals by the naked eye and Raman signals. After a series of optimizations, the constructed sensor could perform simultaneous qualitative and quantitative detection of PEDV and PoRV in just 18 min, with visualized (color signals observed by the naked eye) limits of detection (LOD) of 3.13 × 102 TCID50/mL and 4.69 × 102 copies/μL, respectively. The LOD based on Raman signal analysis was as low as 4.63 × 101 TCID50/mL and 3.30 × 102 copies/μL for PEDV and PoRV, respectively. In addition, the sensor exhibited excellent specificity without cross-reactivity with common pathogens. The overall compliance rate with RT-PCR was 92.1 % (35/38) for 38 clinical samples. Therefore, the sensor is characterized by high sensitivity, specificity, reproducibility, and accuracy, making it suitable for the simultaneous rapid on-site detection of PEDV and PoRV.

Butyrate induces higher host transcriptional changes to inhibit porcine epidemic diarrhea virus strain CV777 infection in porcine intestine epithelial cells

Newborn piglets' health is seriously threatened by the porcine epidemic diarrhea virus (PEDV), which also has a significant effect on the pig industry. The gut microbiota produces butyrate, an abundant metabolite that modulates intestinal function through many methods to improve immunological and intestinal barrier function. The objective of this investigation was to ascertain how elevated butyrate concentrations impacted the host transcriptional profile of PEDV CV777 strain infection. Our findings showed that higher concentrations of butyrate have a stronger inhibitory effect on PEDV CV777 strain infection. According to RNA-seq data, higher concentrations of butyrate induced more significant transcriptional changes in IPEC-J2 cells, and signaling pathways such as PI3K-AKT may play a role in the inhibition of PEDV CV777 strain by high concentrations of butyrate. Ultimately, we offer a theoretical and experimental framework for future research and development of novel approaches to harness butyrate's antiviral infection properties.

Isolation and Identification of a Tibetan Pig Porcine Epidemic Diarrhoea Virus Strain and Its Biological Effects on IPEC-J2 Cells

Porcine epidemic diarrhoea virus (PEDV) is a coronavirus that can cause severe watery diarrhoea in piglets, with high morbidity and mortality rates, seriously hindering the healthy development of the global swine industry. In this study, we isolated a strain of PEDV from Tibetan pigs and named it CH/GS/2022. Subsequently, we screened the apoptosis signals of PEDV-infected IPEC-J2 cells and studied the correlation between apoptosis signals and cell apoptosis. The results showed that different infections of PEDV induced different degrees of apoptosis in cells, and PEDV-induced cell apoptosis was dose-dependent. We then detected the expression of the p53, p38, JNK, Bax, and Bcl-2 genes in the apoptosis signal pathway. The results showed that 24 h after PEDV infection, the expression of the p53, p38, JNK, and Bax genes in IPEC-J2 cells increased significantly, while the expression of the Bcl-2 gene decreased significantly (p < 0.05). Subsequently, we used Western blot to detect the protein levels of these five genes, and the results showed that PEDV infection upregulated the expression of p53, p38, JNK, and Bax proteins (p < 0.05) while downregulating the expression of Bcl-2 protein (p < 0.05). Thus, it was initially inferred that PEDV infection could regulate cell apoptosis by activating the p53, p38, and JNK signalling pathways. Finally, we further investigated the apoptosis of the cells through the use of inhibitors. The results indicated that the p53 inhibitor Pifithrin-α has a significant inhibitory effect on the expression of the p53 protein after PEDV infection and can reverse the expression levels of Bax and Bcl-2 proteins. This suggested that p53 is involved in PEDV-induced cell apoptosis. Similarly, the p38 MAPK inhibitor SB203580 has an inhibitory effect on the expression of the p38 protein and can reverse the expression levels of Bax and Bcl-2 proteins. This suggested that p38 is also involved in PEDV-induced cell apoptosis. On the other hand, the JNK inhibitor SP600125 has no inhibitory effect on the expression of the JNK protein after PEDV infection, but the expression levels of Bax and Bcl-2 proteins have changed. Furthermore, it is noteworthy that SP600125 can inhibit the activity of apoptotic proteins but not their levels, resulting in reduced cell apoptosis. These preliminary results indicated that JNK may be involved in PEDV-induced IPEC-J2 cell apoptosis.