Peste des petits ruminants virus (PPRV) causes an acute and highly contagious disease in domestic and wild small ruminants throughout the world, mainly by invoking immunosuppression in its natural hosts. It has been suggested that the non-structural C protein of PPRV helps in evading host responses but the molecular mechanisms by which it antagonizes the host responses have not been fully characterized. Here, we report the antagonistic effect of PPRV C protein on the expression of interferon-β (IFN-β) through both MAVS and RIG-I mediated pathways in vitro. Dual luciferase reporter assay and direct expression of IFN-β mRNA analysis indicated that PPRV C significantly down regulates IFN-β via its potential interaction with MAVS and RIG-I signaling molecules. Results further indicated that PPRV C protein significantly suppresses endogenous and exogenous IFN-β-induced anti-viral effects in PPRV, EMCV and SVS infections in vitro. Moreover, PPRV C protein not only down regulates IFN-β but also the downstream cytokines of interferon stimulated genes 56 (ISG56), ISG15, C-X-C motif chemokine (CXCL10) and RIG-I mediated activation of IFN promoter elements of ISRE and NF-κB. Further, this study deciphers that PPRV C protein could significantly inhibit the phosphorylation of STAT1 and interferes with the signal transmission in JAK-STAT signaling pathway. Collectively, this study indicates that PPRV C protein is important for innate immune evasion and disease progression.

Background: Encephalomyocarditis virus, member of Cardiovirus genus within Picornaviridae family, is an important pathogen that infects different domestic and wild animals. However, the molecular mechanism of its entry remains unclear. In this study, we investigated the mechanism of EMCV infectivity in relation to endocytic pathway using BHK-21 cells. Methods: The function of numerous cellular key factors implicated in the various endocytic mechanisms were systematically explored using chemical inhibitors. Furthermore, RNA interference (RNAi) as well as the overexpression of dominant protein combined to virus infectivity assays, and confocal microscopy was used to examine EMCV infection in details. Results: The results indicated that the EMCV entry into BHK-21 cells depends on caveolin, dynamin, and actin but not clathrin nor macropinocytosis pathways. The effects of overexpression and knockdown of caveolin-1, one components of the caveolae, was examined on EMCV infection. The results showed that EMCV infection was positive correlation with caveolin-1 expression. Confocal microscopy analysis and internalization assay showed that caveolin-1 is required at the early stage of EMCV infection. Conclusions: Caveolin-1, dynamin, and actin-dependent endocytosis pathways are necessary for EMCV infection in vitro.

Bovine respiratory syncytial virus (BRSV) is an enveloped RNA virus that utilizes clathrin-mediated endocytosis for cell entry and is a significant pathogen in bovine respiratory disease (BRD). Heat shock protein family A member 4 (HSPA4), a member of the HSP70 family, is known to be involved in the progression of various cancers. However, its role in virus entry has not been previously explored. Through experiments involving Western blot analysis, virus titer, and virus copies analysis, we demonstrated that HSPA4 can regulate BRSV entry and replication. The specific regulation mode is to enhance BRSV entry by promoting clathrin-mediated endocytosis. We used Western blot, virus titer, virus copies analysis, and IFA to demonstrate that HSPA4 can promote clathrin heavy chain protein (CHC) expression and further promote BRSV entry by activating the PI3K–Akt signaling pathway. Furthermore, we observed that HSPA4 boosts the efficiency of clathrin-mediated endocytosis by increasing the ATPase activity of heat shock cognate protein 70 (HSC70), thereby facilitating BRSV entry. Additionally, our investigation into the impact of HSPA4 on the entry of other viruses revealed that HSPA4 can facilitate the entry of a variety of viruses into host cells.

Encephalomyocarditis virus (EMCV) has been discovered on pig farms worldwide and can cause myocarditis in piglets and reproductive failure in sows. However, little is known about the host transcriptional responses to infection and host-pathogen interactions. In this study, transcription profiling was performed by Illumina RNA-Sequencing (RNA-seq) to identify EMCV induced differentially expressed genes in BHK-21 cells at serial time points (12, 24, and 30 h post infection (hpi)), using mock infected cells as control. We identified 237, 241, and 207 differentially expressed genes (DEGs) respectively, majority of which were up-regulated. A large number of DEGs clustered into host defense, cellular signaling and metabolism categories. Moreover, short time series expression analysis revealed that 12 hpi was an important time point for expression change, indicating host virus resistance. This RNA-seq analysis provides the first data for understanding the network of virus host interactions under EMCV infection in vitro, and for identifying host components which involved in the virus infection course.

Excessive adipose tissue accumulation in sheep disrupts insulin signaling, inducing insulin resistance, and alters energy partitioning mechanisms. These changes adversely affect both ovine health and production efficiency. This study employed whole-genome resequencing to conduct selection signal analysis in long-fat-tailed (Lanzhou fat-tailed sheep) and short-fat-tailed (Hu sheep) breeds, investigating the genetic basis underlying divergent lipid metabolism-related traits between these distinct tail phenotypes. Fifteen healthy adult individuals, each from long-fat-tailed (Lanzhou Large-tailed sheep) and short-fat-tailed (Hu sheep) breeds, underwent whole-genome resequencing. Whole-genome resequencing analyses via F_ST, XP-CLR, and XP-EHH identified 75 significantly selected regions (p < 0.01), revealing eight key candidate genes (DAB1, DPP10, EPHA6, GPC5, KLF12, PAK7, PTPN3, TENM3). Subsequent functional enrichment analysis demonstrated significant enrichment of DAB1 and GPC5 in lipid metabolic processes (GO:0006629). Employing whole-genome resequencing-based selection signal analysis in long-fat-tailed (Lanzhou Large-tailed sheep) and short-fat-tailed (Hu sheep) breeds, this study identified two key lipid metabolism-associated genes (DAB1 and GPC5). These findings provide critical insights for conserving genetic resources and informing molecular breeding strategies targeting divergent tail phenotypes.

Background: Rabbit hemorrhagic disease (RHD) is an acute, hemorrhagic and highly lethal infectious disease caused by rabbit hemorrhagic disease virus (RHDV), which causes huge economic losses to the rabbit breeding industry. Moreover, there is limited cross-protection between the two different serotypes of classic RHDV (GI.1) and RHDV2 (GI.2). The shortcomings of traditional inactivated vaccines have led to the development of novel subunit vaccines that can protect against both strains, and the VP60 capsid protein is the ideal antigenic protein. This study focused on developing a bivalent RHDV vaccine that can prevent infection with both GI.1 and GI.2 strains. Methodology: Baculovirus vectors containing classic RHDV and RHDV2 VP60 were co-transfected with linearized baculovirus into sf9 cells and transferred to baculovirus via homologous recombination of the VP60 gene. Infected sf9 cells were lysed, and after purification via Ni-NTA chromatography, VLPs were observed using transmission electron microscopy (TEM). In order to evaluate the immunogenicity of the chimeric RHDV VLP vaccine in rabbits, the RHDV VP60-specific antibody, IL-4, IFN-γ and neutralizing antibody titers were analyzed in serum using ELISA and HI. Results: The recombinant baculovirus system successfully expressed chimeric RHDV VLPs with a diameter of 32–40 nm. After immunization, it could produce specific antibodies, IL-4 and IFN-γ. Following the second immunization, neutralizing antibodies, determined using hemagglutination inhibition (HI) assays, were elicited. Conclusions: These data show that the chimeric RHDV VLP bivalent vaccine for immunized New Zealand rabbits can induce humoral immunity and cellular immunity in vivo, and the immunization effect of the high-dose group is similar to that of the current commercial vaccine.