Octyl gallate targeting the 3C-like protease exhibits highly efficient antiviral activity against swine enteric coronavirus PEDV

Repurposing Vancomycin as a Potential Antiviral Agent Against PEDV via nsp13 Helicase Inhibition

Porcine epidemic diarrhea virus (PEDV) causes a highly contagious intestinal disease with severe economic impacts on the global swine industry. The non-structural protein 13 (nsp13), a viral helicase, is essential for viral replication, making it a promising target for antiviral drug development. In this study, through virtual screening and molecular dynamics simulations, Vancomycin, a small-molecule drug also clinically used as an antibacterial agent, was identified to exhibit a stable binding affinity for PEDV nsp13. The NTPase and ATP-dependent RNA helicase activities of PEDV nsp13 were confirmed in vitro, and the optimal biochemical reaction conditions for its dsRNA unwinding activity were established. Further experiments demonstrated that Vancomycin effectively inhibited the dual enzymatic activities of PEDV nsp13 and reduced PEDV infections in vitro. This research highlights Vancomycin as a novel inhibitor of PEDV nsp13, providing valuable mechanistic insights and serving as a model for antiviral drug discovery. While this study suggests its potential for repurposing as a therapeutic agent against PEDV, further investigations are required to evaluate its feasibility in vivo, particularly in terms of safety, efficacy, and practical applicability.

Ethyl caffeate as a novel targeted inhibitor of 3CLpro with antiviral activity against porcine epidemic diarrhea virus

Porcine epidemic diarrhea virus (PEDV) can cause severe diarrhea death in newborn piglets, resulting in significant economic losses for the pig industry. Therefore, the advancement of safe and effective anti-PEDV drugs for the treatment of PEDV is of paramount importance. In this study, molecular docking was used to screen natural drugs that can target PEDV 3C like protease (3CLpro). As well, the anti-PEDV effects of the screened drugs were evaluated in vitro and in vivo. Molecular docking and molecular dynamics (MD) simulation results showed that ethyl caffeate (EC) could efficiently bind to the active cavity of PEDV 3CLpro. Biolayer interferometry (BLI) and fluorescence resonance energy transfer (FRET) analyses demonstrated that EC directly interacts with PEDV 3CLpro (KD = 1650 μM) and inhibits the activity of 3CLpro (IC50 = 33.87 μM). EC has been shown to significantly inhibit the replication of PEDV in Vero E6 cells. The half maximal inhibitory concentration (CC50) and half-effective concentration (EC50) were determined to be 283.1 μM and 8.641 μM, respectively, yielding a selectivity index as high as 32.7. Furthermore, EC was evaluated using a piglet infection model for PEDV. It demonstrated the ability to inhibit PEDV infection in vivo and improve the survival rate of piglets (3/5, 60%). Compared to the control group, oral administration of EC significantly reduced intestinal pathological damage and viral load. Our study indicated that EC, targeting PEDV 3CLpro, is a safe and effective anti-PEDV drug with promising clinical application prospects.

Swine Acute Diarrhea Syndrome Coronavirus: An Overview of Virus Structure and Virus-Host Interactions

SADS-CoV, a recently identified Rhinolophus bat coronavirus HKU2-associated swine coronavirus, is a malignant pathogen that causes acute diarrhea, severe diarrhea, and weight loss in infected piglets. The virus was first detected in Guangdong Province, China, in 2017 and has since been observed in Jiangxi, Fujian, and Guangxi Provinces. In 2023, the virus was detected in Henan Province, in inland China. This virus can infect various cell lines, including human cell lines, showing significant potential for cross-species transmission and posing a possible zoonotic threat. However, the molecular biology of SADS-CoV remains largely unknown, and there are no commercially available therapeutics or vaccines to prevent SADS-CoV infection. In this review, an update on progress in SADS-CoV research is provided, with a focus on the history of outbreaks, the characteristics of the virus, its interactions with the host, and developments in therapeutics and vaccines.

Advances research in porcine enteric coronavirus therapies and antiviral drugs

The porcine enteric coronaviruses (PECs) currently reported include porcine epidemic diarrhea virus (PEDV), porcine deltacoronavirus (PDCoV), transmissible gastroenteritis virus (TGEV), and swine acute diarrhea syndrome coronavirus (SADS-CoV). In the absence of effective treatment, they can cause similar clinical characteristics including weight loss, sleepiness, vomiting, anorexia and fatal diarrhea in neonatal piglets, resulting in significant economic losses to the global pig industry. Although many studies on drugs for treating and combating PECs have been issued. There are still no specific drug targeting PECs and used in clinical production. Therefore, it is necessary to sort out and summarize the research on the treatment and anti PECs drugs, and further development of low toxicity and high efficiency drugs is needed. Here, we review the latest progress of anti PECs drugs, focus on the mechanism of anti PECs reaction of drug components, and try to clarify new strategies for effective control and elimination of PECs. These comprehensive and profound insights will help to further investigate, prevent and control the transmission of PECs infection.

Isolation and characterization of a novel S-gene mutation porcine deltacoronavirus with high pathogenicity from diarrhea piglet in Zhejiang Province, China, 2022

Porcine deltacoronavirus (PDCoV) is a coronavirus that causes diarrhea in suckling piglets and has the potential for cross-species transmission. Monitoring PDCoV evolution and identifying potential vaccine candidates are crucial due to its high mutation rates in pig populations. In this study, a Chinese PDCoV strain named ZD2022 was successfully isolated from diarrhea piglets in Zhejiang province, followed by genetic evolutionary analysis, assessment of S proteins' biological functions, in vitro cellular adaptation analysis and pathogenicity evaluation. Phylogenetic analyses placed the PDCoV ZD2022 strain within the Southeast Asia Lineage. Sequence analysis revealed 23 mutations in the S protein of ZD2022 compared to most of other Chinese PDCoV strains, including 8 unique mutations (T529I, L579F, Q614H, V709G, S959L, P1010S, V1016F, A1068V). In addition, bioinformatic predictions indicated these mutations impact the hydrophilicity/hydrophobicity, antigenic epitopes and N-glycosylation sites of the ZD2022 S protein. The virus growth curve of ZD2022 showed good cellular adaptation, with peak viral titers of 8.92 ± 0.31 Log10 TCID50/mL in ST cells. Furthermore, ZD2022 exhibited high virulence in suckling piglets, causing severe diarrhea in piglets at 60 h post-inoculation (hpi) and a mortality rate of 40 % (2/5) within 96 hpi. In summary, our findings indicate that the Chinese PDCoV strains continue to mutate, and the novel S gene mutation in strain ZD2022 offers strong cellular adaptation and high pathogenicity, making it a potential candidate strain for vaccine development.

Construction and immune effect evaluation of the S protein heptad repeat-based nanoparticle vaccine against porcine epidemic diarrhea virus

Porcine epidemic diarrhea virus (PEDV), a highly virulent enteropathogenic coronavirus, is a significant threat to the pig industry. High frequency mutations in the PEDV genome have limited the effectiveness of current vaccines in providing immune protection. Developing efficient vaccines that can quickly adapt to mutant strains is a challenging but crucial task. In this study, we chose the pivotal protein heptad repeat (HR) responsible for coronavirus entry into host cells, as the vaccine antigen. HR-Fer nanoparticles prepared using ferritin were evaluated them as PEDV vaccine candidates. Nanoparticle vaccines elicited stronger neutralizing antibody responses in mice compared to monomer vaccines. Additionally, HR protein delivered via nanoparticles increased antigen uptake by antigen-presenting cells in vitro by 2.75-fold. The collective results suggest that HR can be used as antigens for vaccines, and the HR vaccine based on ferritin nanoparticles significantly enhances immunogenicity.

Natural hyperoside extracted from hawthorn exhibits antiviral activity against porcine epidemic diarrhea virus in vitro and in vivo

Porcine epidemic diarrhea virus (PEDV) causes severe diarrhea and death in piglets, resulting in significant economic losses for the pork industry. There is an urgent need for new treatment strategies. Here, we focused on optimizing the process of purifying natural hyperoside (nHYP) from hawthorn and evaluating its effectiveness against PEDV both in vitro and in vivo. Our findings demonstrated that nHYP with a purity >98% was successfully isolated from hawthorn with an extraction rate of 0.42 mg/g. Furthermore, nHYP exhibited strong inhibitory effects on PEDV replication in cells, with a selection index of 9.72. nHYP significantly reduced the viral load in the intestines of piglets and protected three of four piglets from death caused by PEDV infection. Mechanistically, nHYP could intervene in the interaction of PEDV N protein and p53. The findings implicate nHYP as having promising therapeutic potential for combating PEDV infections.

Licorice extract inhibits porcine epidemic diarrhea virus in vitro and in vivo

Porcine epidemic diarrhea virus (PEDV) causes severe diarrhea and even death in piglets, resulting in significant economic losses to the pig industry. Because of the ongoing mutation of PEDV, there might be variations between the vaccine strain and the prevailing strain, causing the vaccine to not offer full protection against different PEDV variant strains. Therefore, it is necessary to develop anti-PEDV drugs to compensate for vaccines. This study confirmed the anti-PEDV effect of licorice extract (Le) in vitro and in vivo. Le inhibited PEDV replication in a dose-dependent manner in vitro. By exploring the effect of Le on the life cycle of PEDV, we found that Le inhibited the attachment, internalization, and replication stages of the virus. In vivo, all five piglets in the PEDV-infected group died within 72 h. In comparison, the Le-treated group had a survival rate of 80 % at the same time, with significant relief of clinical symptoms, pathological damage, and viral loads in the jejunum and ileum. Our results suggested that Le can exert anti-PEDV effects in vitro and in vivo. Le is effective and inexpensive; therefore it has the potential to be developed as a new anti-PEDV drug.