Remdesivir inhibits Porcine epidemic diarrhea virus infection in vitro.

Porcine Epidemic Diarrhea Virus (PEDV) is a highly contagious and pathogenic virus that causes symptoms such as diarrhea, vomiting, weight loss, and even death in piglets. Due to its high transmission rate, PEDV has resulted in significant global losses. Although some vaccines have been developed and utilized to prevent PEDV, their effectiveness is limited due to the virus's mutations. Therefore, it is imperative to investigate new strategies to combat PEDV. Remdesivir, a classic antiviral drug for coronaviruses, has been proven in our experiment to effectively suppress PEDV replication in Vero and LLC-PK1 cells. Additionally, the cell experiment demonstrated its direct inhibition of PEDV RNA-dependent RNA polymerase (RdRp) enzyme activity. Molecular docking simulations were employed to predict the binding site of remdesivir and PEDV RdRp. Moreover, we observed that remdesivir does not impact the production of inflammatory factors and exhibits antagonistic effects with exogenous nucleosides. Furthermore, we conducted RNA-Seq analysis to investigate the global changes in transcriptome of infected cells treated with remdesivir. Overall, our findings indicate that remdesivir holds promise as a potential candidate for the treatment of PEDV infection.

Molnupiravir Inhibits Porcine Epidemic Diarrhea Virus Infection In Vitro.

Porcine epidemic diarrhea virus (PEDV) is a swine coronavirus that is highly infectious and prone to variation. Vaccines derived from traditional PEDV strains provide less protection against PEDV-variant strains. Furthermore; there is a complex diversity of sequences among various PEDV-variant strains. Therefore; there is an urgent need to develop alternative antiviral strategies to defend against PEDV. Molnupiravir is a nucleotide analogue that could replace natural nucleosides to restrain viral RNA replication. Our study provided evidence for the dose-dependent inhibition of PEDV replication by molnupiravir in Vero cells. Molnupiravir also exhibited a strong inhibitory effect on viral RNA and protein production. Our results demonstrated that molnupiravir inhibits PEDV RNA-dependent RNA polymerase (RdRp) activity and induces a high frequency of mutations in the PEDV genome. Further studies revealed that molnupiravir can reverse changes in the transcriptome caused by viral infection. In conclusion, our results indicated that molnupiravir has the potential to be an effective treatment for PEDV infection.

Porcine Epidemic Diarrhoea Virus Induces Cell-cycle Arrest through the DNA Damage-signalling Pathway.

INTRODUCTION: Porcine epidemic diarrhoea virus (PEDV) infection causes watery diarrhoea, vomiting, anorexia, and weight loss, especially among neonatal piglets, inflicting on them morbidity and mortality potentially reaching 90%-100%. Despite it being known that certain mammalian cell phases are arrested by PEDV, the mechanisms have not been elucidated, and PEDV pathogenesis is poorly understood. This study determined the effect of an epidemic PEDV strain on cell cycle progression. MATERIAL AND METHODS: We observed the effect of the PEDV SHpd/2012 strain on an infected Vero cell cycle through flow cytometry and Western blot, investigating the interrelationships of cell-cycle arrest, the DNA damage-signalling pathway caused by PEDV and the phosphorylation levels of the key molecules Chk.2 and H2A.X involved upstream and downstream in this pathway. RESULTS: PEDV induced Vero cell-cycle arrest at the G1/G0 phase. The phosphorylation levels of Chk.2 and H2A.X increased with the prolongation of PEDV infection, and no significant cell-cycle arrest was observed after treatment with ATM or Chk.2 inhibitors. The proliferation of PEDV was also inhibited by treatment with ATM or Chk.2 inhibitors. CONCLUSION: PEDV-induced cell-cycle arrest is associated with activation of DNA damage-signalling pathways. Our findings elucidate the molecular basis of PEDV replication and provide evidence to support further evaluation of PEDV pathogenesis.

Effects of water-borne copper on the Y-organ and content of 20-hydroxyecdysone in Eriocheir sinensis.

The effects of water-borne copper (Cu2+) (0.01, 0.10, 1.00, and 5.00 mg/L) on Y-organ (YO) microstructure and ultrastructure and on the content of 20-hydroxyecdysone (20-HE) in Eriocheir sinensis were studied using single gradient factor experiments. Results demonstrated that there was no significant difference in YO microstructure and ultrastructure when E. sinensis was exposed to 0.01, 0.10, and 1.00 mg/L water-borne Cu2+. However, exposure to 5.00 mg/L Cu2+ caused serious damage to the YO microstructure, with an obvious decrease in hemocoel and the disappearance of the basement membrane between cell fibers. In addition, there was an intumescence of cells around the hemocoel, the cell nucleus became enlarged or even rounded, and some cells around the hemocoel crumpled with only the cell nucleus isolated or even huddled in the hemocoel. Similarly, effects of water-borne Cu2+ on the YO ultrastructure were observed: obvious enlargement and rounding of the cell nucleus, high heterochromatinization of the nucleus chromatin, disappearance of the YO cell membrane in some severely damaged cells, and varied damage in cellular organelles, such as the disappearance of cristae in mitochondria and disruption of the nucleus membrane. The hemocyte nucleus showed considerable heterochromatinization. In addition, when the Cu2+ concentration increased, the content of 20-hydroxyecdysone (20-HE) decreased in all Cu2+ treatment groups (P < 0.05). Results of this study indicate that high water-borne Cu2+ concentration impaired the basic structure of YO, which is regarded as the secretion site of 20-HE, and hence decreased the content of 20-HE in hemolymph. Therefore, molting frequency as well as the growth of E. sinensis is inhibited when exposed to high concentrations of water-borne Cu2+.

Effect of waterborne copper on the microstructures of gill and hepatopancreas in Eriocheir sinensis and its induction of metallothionein synthesis.

Effects of different waterborne copper concentrations (0.00, 0.01, 0.10, 1.00, and 5.00 mg/l) on microstructures of gill and hepatopancreas, and in inducing metallothionein (MT) synthesis were studied in Chinese mitten crab Eriocheir sinennsis. The results indicated that copper accumulation caused histologic damage to gill and hepatopancreas and induced MT synthesis in hepatopancreas. No significant differences were found in microstructures between 0.01 mg/l copper treatment and the control group. Exposure to copper concentrations ranging from 0.1 to 5.0 mg/l for 10 days resulted in irregularly thickened lamella, enlarged haemocoels, increased hemocytes, and damaged or disassembled epithelia in gill. Similarly, in hepatopancreas, the spaces of the small blind tubules decreased, and nuclei of the epithelia were karyopycnosised or karyorhexised. Also, the basement membranes were rumpled or even ruptured, with new vacuoles formed between the basement membrane and the simple columnar epithelia. MT measurements showed no significant differences in MT contents between the control group and the group treated with 0.01 mg/l waterborne copper. Maximum MT content was observed at the treatment level of 0.10 mg/l waterborne copper.