Project description:African swine fever virus (ASFV) is a large DNA virus that poses a major threat to the global swine industry. Its virion is encapsulated by an icosahedral capsid predominantly composed of the structural protein p72, which constitutes approximately one-third of the total virion mass. Despite its abundance, the mechanisms regulating p72 stability remain poorly understood. Here, we demonstrate that host-mediated stabilization of p72 is essential for efficient ASFV replication. Mass spectrometry of p72 co-precipitates identified host cyclophilin A (CypA, also known as PPIA) as a key binding partner of p72. CypA interacts with p72 both in vitro and in vivo, specifically engaging exposed regions of p72 via its hydrophobic cavity. CypA interaction stabilizes p72 by reducing K63-linked ubiquitination and preventing proteasomal degradation, whereas cyclic CypA inhibitors destabilize p72 by disrupting this interaction and promoting its ubiquitination. Importantly, genetic or pharmacological inhibition of CypA markedly impairs ASFV replication. Mechanistically, CypA inhibition disrupts viral factory formation and virion assembly by decreasing p72 protein accumulation without affecting its transcription. Together, our findings uncover a previously unrecognized host-dependent mechanism regulating capsid protein stability and highlight host CypA as a promising target for antiviral strategies against ASFV.
Project description:To explore the potential mechanisms regulating p72 stability, we performed co-immunoprecipitation using an anti-p72 antibody in ASFV-infected PAMs, followed by mass spectrometry analysis to identify host factors interacting with p72.
Project description:In field studies and carefully controlled artificial infections, there is host variation in response to ASF infections. To better understand the mechanisms underlying this diversity and distinguish between resilient and susceptible pigs to African Swine Fever (ASF), the differentially expressed genes (DEGs) were studied between the recovered versus non-recovered pigs before and after an infection challenge and also among non-recovered animals over time. In total, 17 Babraham pigs were sampled. Twelve animals were randomly immunized with low virulent ASFV isolate, and the others received the sham vaccine. All animals were then challenged with the virulent ASFV isolate 18 days after the immunization. Except for five animals, all showed clinical signs and dead between 4 and 6 days later. RNA sequencing was done for whole blood samples collected pre-infection, one day, and one week post-infection.
Project description:Large DNA viruses are known to manipulate and modify host miRNAs during infection. Therefore the aim of this study was to investigate the impact of infection with the large DNA virus; African swine fever virus (ASFV) on host miRNAs. Small RNA sequencing libraries were prepared from RNA extracted from ASFV (Benin 97/1) infected primary porcine macrophages at 0, 6 and 16 hours post infection. Libraries were pooled and sequenced on 1 lane of an Illumina HiSeq, yielding sequences aligning to a total of 247 different mature Sus scrofa miRNAs. On average, 3779095 (± 1911525) miRNA reads were obtained per sample. The results revealed no widespread modification to host miRNAs, though a number of specific miRNAs were differentially expressed during ASFV infection. Notably, a small number of miRNAs (Ssc-miR-10b, Ssc-miR-144 and Ssc-miR-486) were rapidly upregulated 2-6 fold within the first hour of infection.
Project description:African swine fever virus (ASFV) is a highly infectious and lethal swine pathogen that causes severe socio-economic consequences in affected countries. Unfortunately, effective vaccine for combating ASF is unavailable so far, and the prevention and control strategies for ASFV are still very limited. Toosendanin (TSN), a triterpenoid saponin extracted from the medicinal herb Melia toosendan Sieb. Et Zucc, has been demonstrated to possess analgesic, anti-inflammatory, anti-botulism and anti-microbial activities, and was used clinically as an anthelmintic, while the antiviral effect of TSN on ASFV has not been reported. In this study, we revealed that TSN exhibited a potent inhibitory effect on ASFV GD955-38 strain in porcine alveolar macrophages (PAMs) (EC50=0.085 μM, SI = 365) in a dose-dependent manner. TSN showed robust antiviral activity in different doses of ASFV infection and reduced the transcription and translation levels of ASFV p30 protein, viral genomic DNA quantity as well as viral titer at 24 and 48 hours post-infection. In addition, TSN did not affect virion attachment and release but intervened in its internalization in PAMs. Further investigations disclosed that TSN played its antiviral role by upregulating the host IFN-stimulated gene (ISG) IRF1 rather than by directly inactivating the virus particles. Overall, our results suggest that TSN is an effective antiviral agent against ASFV replication in vitro and may have the potential for clinical use.
Project description:Long noncoding RNAs (lncRNAs) participate in regulating many biological processes. However, their roles in African swine fever virus(ASFV) pathogenicity are largely unknown. Here, we analyzed the expression profile of lncRNAs and mRNAs in the ASFV-infected or uninfected PAMs by high-throughput sequencing