Bovine viral diarrhea virus (BVDV) causes a severe threat to the cattle industry due to ineffective control measures. Gypenoside is the primary component of Gynostemma pentaphyllum, which has potential medicinal value and has been widely applied as a food additive and herbal supplement. However, little is known about the antiviral effects of gypenoside. The present study aimed to explore the antiviral activities of gypenoside against BVDV infection. The inhibitory activity of gypenoside against BVDV was assessed by using virus titration and performing Western blotting, quantitative reverse transcription PCR (RT-qPCR), and immunofluorescence assays in MDBK cells. We found that gypenoside exhibited high anti-BVDV activity by interfering with the viral attachment to and internalization in cells. The study showed that BVDV infection inhibits apoptosis of infected cells from escaping the innate defense of host cells. Our data further demonstrated that gypenoside inhibited BVDV infection by electively activating the apoptosis of BVDV-infected cells for execution, as evidenced by the regulation of the expression of the apoptosis-related protein, promotion of caspase-3 activation, and display of positive TUNEL staining; no toxicity was observed in non-infected cells. Collectively, the data identified that gypenoside exerts an anti-BVDV-infection role by inhibiting viral attachment and internalization and selectively purging virally infected cells. Therefore, our study will contribute to the development of a novel prophylactic and therapeutic strategy against BVDV infection.

Bovine viral diarrhea virus (BVDV) is a pathogen associated with substantial economic losses in the dairy cattle industry. Currently, there are no effective vaccines against BVDV. Melatonin (MT) has been shown to have anti-inflammatory and anti-viral properties, and the use of MF59 in vaccines significantly enhances vaccine efficiency. Here, MT and MF59 were added into the E^rns-LTB vaccine. Subsequently, their inhibitory activity on the NF-κB signaling pathway in Mardin-Darby Bovine Kidney cells and the hippocampus was assessed using western blot and quantitative reverse transcription PCR. The findings revealed that MT in the E^rns-LTB vaccine decreases the phosphorylation of p65 proteins caused by BVDV infection. In addition, MT decreased the mRNA levels of IL-1β and IL-6 in vitro, but increased the production of IFN-α, IFN-β, Mx1 in vitro, brain-derived neurotrophic factor, cyclic amp response element-binding protein, and the stem cell factor in vivo. Furthermore, treatment with E^rns-LTB + MF59 + MT stimulated the production of T lymphocytes, alleviated pathological damage, decreased expressions of BVDV antigen, and tight junction proteins in mice. These findings imply that MT has potential for use in the E^rns-LTB vaccine to inhibit BVDV infection and regulate the immune responses of T-cells by inhibiting the NF-κB signaling pathway.

Salmonella enterica serovar Infantis (S. Infantis) is an intracellular bacterial pathogen. It is prevalent but resistant to antibiotics. Therefore, the therapeutic effect of antibiotics on Salmonella infection is limited. In this study, we used the piglet diarrhea model and the Caco2 cell model to explore the mechanism of probiotic Lactobacillus johnsonii L531 (L. johnsonii L531) against S. Infantis infection. L. johnsonii L531 attenuated S. Infantis-induced intestinal structural and cellular ultrastructural damage. The expression of NOD pathway-related proteins (NOD1/2, RIP2), autophagy-related key proteins (ATG16L1, IRGM), and endoplasmic reticulum (ER) stress markers (GRP78, IRE1) were increased after S. Infantis infection. Notably, L. johnsonii L531 pretreatment not only inhibited the activation of the above signaling pathways but also played an anti-S. Infantis infection role in accelerating autophagic degradation. However, RIP2 knockdown did not interfere with ER stress and the activation of autophagy induced by S. Infantis in Caco2 cells. Our data suggest that L. johnsonii L531 pretreatment alleviates the intestinal damage caused by S. Infantis by inhibiting NOD activation and regulating ER stress, as well as promoting autophagic degradation.

Bovine viral diarrhea virus (BVDV) is a highly contagious viral disease which causes economic losses to the cattle industry. Ethyl gallate (EG) is a phenolic acid derivative which has various potentials to modulate the host response to pathogens, such as via antioxidant activity, antibacterial activity, inhibition of the production of cell adhesion factors, and so on. This study aimed to evaluate if EG influences BVDV infection in Madin-Darby Bovine Kidney (MDBK) cells, and to understand the antiviral mechanism. Data indicated that EG effectively inhibited BVDV infection by co-treatment and post-treatment in MDBK cells with noncytotoxic doses. In addition, EG suppressed BVDV infection at an early stage of the viral life cycle by blocking entry and replication steps but not viral attachment and release. Moreover, EG strongly inhibited BVDV infection by promoting interferon-induced transmembrane protein 3 (IFITM3) expression, which localized to the cytoplasm. The protein level of cathepsin B was significantly reduced by BVDV infection, whereas with treatment with EG, it was significantly enhanced. The fluorescence intensities of acridine orange (AO) staining were significantly decreased in BVDV-infected cells but increased in EG-treated cells. Finally, Western blot and immunofluorescence analyses demonstrated that EG treatment significantly enhanced the protein levels of autophagy markers LC3 and p62. Chloroquine (CQ) significantly increased IFITM3 expression, and Rapamycin significantly decreased it. Thus, EG may regulate IFITM3 expression through autophagy. Our results showed that EG could have a solid antiviral activity on BVDV replication in MDBK cells via increased IFITM3 expression, lysosomal acidification, protease activity, and regulated autophagy. EG might have value for further development as an antiviral agent.

Bovine viral diarrhea virus (BVDV) is a critical animal pathogen that leads to cattle production losses associated with acute disease, immune dysregulation, reproductive failure, and respiratory disease. Due to the monotonous control technique and neglect of BVDV, increasing prevalence of BVDV has caused significant economic losses in the cattle industry worldwide. Therefore, novel anti-BVDV drugs are essential to prevent and control BVDV. Our previous studies have found that Forsythoside A (FTA) could inhibit the replication of BVDV via TRAF2-dependent CD28-4-1BB signaling in bovine peripheral blood mononuclear cells (PBMCs), but whether they can directly inhibit the BVDV remains unclear. Here, we further investigated the effects of FTA on BVDV and its underlying mechanisms of action. We found that FTA significantly inhibited the replication of BVDV in the MDBK cell directly. The results demonstrated that FTA could reduce the functional activation of Caspase-1 to inhibit the inflammatory response caused by BVDV infection and increase the expression of type I interferon (IFN-I) to clear the virus in vitro. The animal experiment was performed to evaluate the antiviral effect of FTA in vivo. Notably, after challenged with BVDV, mice with FTA + E^rns-E2 protein displayed alleviated pathological damage and decreased the viral load in the spleen compared with mice inoculated with E^rns-E2 protein. Furthermore, treatment with FTA enhanced body defense and delayed infection by the BVDV. Our results reveal that FTA suppresses BVDV replication both in vitro and in vivo and therefore shows promise as an anti-BVDV agent.