Porcine circovirus type 2 (PCV2) is a globally prevalent viral pathogen that causes substantial economic losses in the swine industry. Rapid and accurate on-site diagnosis is critical for controlling the spread of PCV2. In recent years, RNA-guided CRISPR/Cas12a nucleases combined with recombinase polymerase amplification (RPA) have emerged as a promising approach for nucleic acid detection. This study aimed to develop a novel RPA-CRISPR-based method for the rapid and sensitive detection of PCV2 in field settings. We designed and optimized CRISPR RNAs (crRNAs) targeting conserved regions of the PCV2 Cap and Rep genes. Upon recognition of the target sequence, the Cas12a nuclease was activated to cleave a single-stranded DNA-fluorophore quencher (ssDNA-FQ) reporter, generating a fluorescent signal detectable either by a fluorescence detector or via visual readout. The entire procedure was performed at 37 °C and completed within one hour. The assay achieved a detection limit as low as 10 copies/µL and showed no cross-reactivity with other major porcine viruses. Furthermore, a rapid-release reagent was used to replace conventional DNA extraction from serum samples, facilitating efficient on-site detection. The assay was validated using clinical samples, and the results showed strong concordance with those obtained by PCR. The RPA-CRISPR-based assay developed in this study is highly sensitive and specific, enabling detection of PCV2 within one hour. Its simplicity, rapidity, and ease of use in the field offer significant practical advantages, making it a valuable tool for the on-site diagnosis of PCV2. This method represents a promising alternative for the early and rapid detection of PCV2 infections and holds potential for contributing to the prevention and control of the disease in the swine industry.

The role of the cAMP/PKA pathway in antiviral innate immunity, including during coronavirus infections, remains unclear. We discovered coronavirus N proteins initiate cAMP-ADCY10-PKA cascade. Cytoplasmic PKA activates STAT1 independently of canonical JAK/TYR2 signaling. Coronavirus N proteins, via a conserved arginine (e.g., PEDV R58, SARS-CoV-2 R92), directly bind and sequester PKA Cα into the nucleus to evade STAT1 activation. Using PEDV as a model, mutant viruses with NmutNLS and NR58A were generated. Wildtype PEDV infection suppressed STAT1 activation in cells expressing PKA Cα/PKA CαS339A deficient in STAT1 phosphorylation. However, in rXS0101mutNLS- or rXS0101R58A-infected cells, only PKA CαS339A expression inhibited STAT1 activation. Downregulation of STAT1 activation is accompanied with increased viral replication. This study first elaborates that PKA Cα activates STAT1 in the cytoplasm of infected cells distinctly from canonical JAK/STAT1 signaling, while coronaviruses evade this antiviral response by sequestering PKA Cα into the nucleus via direct N protein interaction.

Cap VLPs (virus-like-particles) are self-assembling nanoparticles (NPs) derived from PCV2 ORF2 with ordered and repetitive antigen display, which have been widely used as a landmark veterinary vaccine in the swine industry. Building upon the pivotal role of virus-activated autophagy in antigen presentation and immune regulation, efforts were made to identify the key molecular elements and mechanisms by which Cap NPs activate autophagy to enhance immunogenicity and expand their application as a vaccine platform. Self-assembled Cap NPs exhibited efficient cell internalization, upregulated various immune regulatory cytokines, particularly TNF-α, and promoted the expression of molecules involved in antigen presentation. Cap NPs induced autophagy by activating the CaMKKβ-AMPK-mTOR pathway and elevating intracellular ROS, which facilitated the processing and degradation of the Cap antigen and led to subsequent activation of TNF-α signaling. Inhibition of either autophagy or TNF-α downregulated antigen presentation. The animal immunization experiment confirmed that Cap NP-induced autophagy and TNF-α signaling promoted humoral and cellular immune responses. To further investigate the key components affecting immunogenicity, truncated Cap peptides were displayed on self-assembled mi3 nanoparticles. Among these, the chimeric mC-9-10 NPs autonomously induced autophagy-TNF-α signaling and stimulated immune responses, suggesting potential adjuvant-like activity. More importantly, Cap NPs were able to enter and activate autophagy-TNF-α signaling in multiple cell lines across different species, making them candidates for a broad-spectrum antigen delivery nano-vaccine platform. Overall, this work not only systematically elucidates the complete molecular mechanisms by which Cap NPs enhance immune responses through cellular internalization, autophagy induction, TNF-α signaling activation, and antigen presentation, but also highlights the great potential of Cap NPs and their functional peptides as multi-species nano-vaccine carriers and novel immune adjuvants. These findings provide a solid theoretical foundation and technical feasibility for the design of next-generation nano-delivery platforms and the development of immune-enhancing tools.

Bacillus amyloliquefaciens SC06 (BaSC06) has emerged as a promising probiotic for improving animal gut health and immuno-protection. However, the underlying molecular mechanisms remain incompletely understood. In this study, we employed porcine intestinal organoids as an ex vivo model and induced oxidative stress using diquat to systematically evaluate the protective effects of BaSC06. We evaluated antioxidant capacity, apoptosis-related markers, intestinal stem cells differentiation markers, and associated signaling pathways. Pretreatment with BaSC06 significantly alleviated oxidative damage by reducing intracellular reactive oxygen species levels and resultant apoptosis. Cellularly, BaSC06 promoted intestinal stem cells proliferation and favored differentiation toward Paneth cells while suppressing differentiation into other epithelial lineages. Mechanistically, these effects were mediated by the activation of the Wnt signaling pathway, and it was further confirmed by using a specific Wnt inhibitor. Overall, our findings uncover a probiotic-Wnt axis through which BaSC06 confers protection against oxidative stress, involving modulation of intestinal stem cells fate and enhancement of epithelial barrier function.

Diseases associated with porcine circovirus type 2 (PCV2) and pseudorabies virus (PRV) significantly affect the economy of pig farms, particularly when combined infections lead to bacterial co-infections. Antigens from the pseudorabies variant strain gB and gD proteins and PCV2 (genotyped) Cap protein were mixed with the pattern recognition receptor (PRR) agonist FLICd as adjuvants and formulated with a micro-hydrogel adjuvant into PCV2 and PRV bivalent subunit vaccines. Twenty pigs, aged 30-35 days, were divided into groups A (received bivalent subunit vaccine) and B (received bivalent subunit vaccines with recombinant FLICd adjuvant), as well as C (non-vaccinated challenge control) and D (blank control). Groups A and B showed no significant difference in average daily weight gain compared to the unvaccinated controls. Fourteen days post-second vaccination, groups A and B exhibited significantly higher levels of PRV and PCV2 antibodies than groups C and D. Group B showed significantly higher average titers of PRV-specific neutralizing antibodies than group A. Fourteen days post-second vaccination, a PRV (ZJM-1 strain) challenge test was conducted. The vaccinated group achieved 100% protection. Vaccination effectively reduced virus load post-challenge and shortened the PRV shedding period. Vaccination with PCV2 and PRV bivalent subunit vaccines effectively prevents the onset of PCV2-related diseases and infections by wild pseudorabies strains.

ETHNOPHARMACOLOGICAL RELEVANCE:The Zhimu-Huangbai herb-pair (ZB) is one of the most widely accepted prescriptions for treating Alzheimer's disease (AD) in traditional Chinese medicine. However, the effective components and mechanism of ZB for treating AD have not been fully understood. AIM OF THE STUDY:This study aims to reveal the active components of ZB in the treatment of AD through serum pharmacochemistry, identify the potential targets and pathways of ZB in treating AD through metabolomics, and subsequently verify its mechanism through in vivo experiments. MATERIALS AND METHODS:The components of ZB in both blood and cerebrospinal fluid were determined by using UPLC-Q-TOF-MS. The efficacy of ZB was assessed in a mouse model of AD induced by D-galactose. Metabolomics methods were used for screening and identification of differential metabolites and enrichment analysis of metabolic pathways. The enzyme-linked immunosorbent assay (ELISA) was used to detect the activities of enzyme complexes I-IV, as well as the levels of ATP and ROS in hippocampal mitochondria of mice. Additionally, the expression of key genes and proteins in the signaling pathway was examined by utilizing immunohistochemistry, real-time quantitative PCR, and Western blot. RESULTS:A total of 27 prototype components were identified from the serum of rats given ZB, of which 8 components were simultaneously detected in the cerebrospinal fluid. A total of 20 different metabolites were identified from mouse plasma using a metabolomics technique. The enrichment analysis results revealed that the pathway of ZB treatment for AD mainly involves glycerophospholipid metabolism, arachidonic acid metabolism, and unsaturated fatty acid biosynthesis. In vivo experiments have shown that ZB can improve the energy metabolism of the brain and increase the production of ATP by improving mitochondrial dysfunction. In addition, ZB could promote the release of brain-derived neurotrophic factor (BDNF), increase the density of postsynaptic density protein (PSD95), and enhance the expression of synaptophysin (SYN). CONCLUSION:Our study demonstrates that ZB can improve mitochondrial and synaptic function in AD mice induced by D-gal, providing experimental support for the clinical application and drug development for the prevention and treatment of AD.

Porcine deltacoronavirus (PDCoV) is a newly discovered porcine intestinal coronavirus that can pose a significant threat to the global commercial swine industry. We established an enzyme-linked immunosorbent assay (ELISA) detection method for the detection of PDCoV antibodies, based on the recombinant nucleocapsid (N) protein expressed using a baculovirus system. The assay was validated using positive and negative serum samples obtained from experimentally immunized rabbits and demonstrated an absence of cross-reactivity with either transmissible gastroenteritis virus (TGEV) or porcine epidemic diarrhea virus (PEDV). The recombinant PDCoV N protein antigen dilution (0.8 μg/mL), sample serum (1:400), and the enzyme-labeled secondary antibody (1:50) were used in this assay. The cut-off value was 0.355, without cross-reactivity including TGEV and PEDV. The ELISA method shows good sensitivity (96.67%), specificity (85.51%), and reproductivity (CV < 10%). We utilized the method to detect PDCoV antibodies in 600 pig serums collected from Zhejiang Province in the last four years (2021–2024). The results showed significant differences in antibody levels between regions and considerable fluctuation in positivity rates across the four-year period. As shown in the results, we developed a sensitive and specific ELISA method for detecting anti-PDCoV N antibodies, which provides a rapid and reliable diagnostic tool for PDCoV surveillance and control. This assay demonstrates significant potential for both epidemiological investigations and commercial applications in swine disease management.

Coronaviruses are capable of inducing diverse infectious diseases that pose significant threats to the public health and the economic development. With a single positive-stranded RNA genome, coronaviruses utilize viral proteins to execute diverse immune escape strategies to facilitate their replication. Of all the identified structural proteins and non-structural proteins within the coronaviruses, nucleocapsid (N) protein is highly conserved and is the most abundant viral protein in infected host cells. N protein regulates the more complex and diverse mechanisms through which viruses suppress host immunity. In this review, we analyzed the basic structure of coronavirus N protein, and further elaborate on its multifaceted regulatory functions in the virion assembly, pathogenesis, host innate immune responses, as well as the innate immunity-related programmed cell death and cell cycle, and also other cell processes. A better understanding of the immune evasion strategy regulated by N protein will help to provide a theoretical basis for the development of broad-spectrum anti-coronavirus drugs targeting N proteins.

Porcine epidemic diarrhea virus (PEDV), a member of the Coronaviridae family, responsible for substantial morbidity and mortality in neonatal piglets, representing an ongoing threat to the swine industry. The type I interferon (IFN) response is integral to the innate immune system, playing a critical role in host defense against viral infection. However, viruses have evolved diverse strategies to evade or suppress host immune responses to facilitate their replication. In this study, we demonstrate that PEDV targets Caspase-1 to enhance its replication and suppress IFN-β production. PEDV infection increases the expression of Caspase-1 in both tissues and cells. Overexpression of Caspase-1 significantly reduces IFN-β production while promoting PEDV replication. The suppression of IFN-β production by Caspase-1 is mediated through the cleavage of mitochondrial antiviral signaling (MAVS). Specifically, Caspase-1 cleaves MAVS at Asp182, facilitating viral replication and inhibiting IFN-β production. The resulting MAVS fragments, once cleaved, lose their ability to both inhibit viral replication and induce IFN-β production, thereby enabling PEDV proliferation. Additionally, we observe that Caspase-1 exhibits species-specific cleavage effects on MAVS, though its impact on MAVS cleavage remains consistent. This study provides a novel target for anti-PEDV therapeutic strategies.

Porcine circoviruses 3 (PCV3) and 4 (PCV4) are emerging pathogens with global implications for swine industry, disturbing the diagnosis of PCVs associated diseases due to a range of similar clinical symptoms and increasingly coinfections. A rapid and accurate method for detection of PCV3 and PCV4 is critical for controlling the transmission of associated disease. We developed a duplex real-time recombinase aided amplification (RAA) assay for detection of both PCV3 and PCV4 simultaneously. The assay was completed within 20 min at 39℃ with the designed optimal primers and probes. The established assay was more convenient and simpler operation compared with conventional molecular biological assays. The assay achieved a detection limit of 73.67 copies/reaction for each circovirus (at 95

Porcine enteric coronaviruses (CoVs), including swine acute diarrhea syndrome coronavirus (SADS-CoV), porcine epidemic diarrhea virus (PEDV), porcine deltacoronavirus (PDCoV), and porcine transmissible gastroenteritis virus (TGEV), are major pathogens causing porcine viral diarrhea syndrome (VDS), which brings significant economic losses to the swine industry; distinguishing between these clinically similar viruses has become a serious challenge. We developed a highly specific and interference-resistant porcine CoV multiplex digital PCR (dPCR) assay. The assay exhibited robust anti-interference capabilities, as the concentrations of the four viruses did not affect their accurate quantification. The coefficients of variation (CV%) of intra-batch and inter-batch repeatability for all target viruses were less than 11%. The limit of quantification (LoQ) of this dPCR assay reached 7.5 copies/reaction for each target, and it was one order of magnitude more sensitive than qPCR. The limits of detection (LoD) for SADS-CoV, PEDV, PDCoV, and TGEV were 2.72, 3.00, 3.56, and 3.19 copies/reaction, respectively. A total of 408 known samples were used for validation tests, and the results were highly consistent with the known conditions, showing a compliance rate of 97-100%. The diagnostic specificity (Dsp) of the method was 99-100%. In conclusion, the developed multiplex dPCR assay is highly suitable for early detection and quarantine in four porcine CoVs. The results indicate that this dPCR method is characterized by high specificity, anti-interference capabilities, repeatability, and high sensitivity. It also demonstrates a high compliance rate and diagnostic specificity in sample detection. This multiplex dPCR will contribute to the control of porcine enteric CoV-caused VDS and provide clues for subsequent research.

Porcine reproductive and respiratory syndrome virus (PRRSV) is an immune-suppressive pathogen that poses a significant challenge to the global swine industry. The mechanism by which PRRSV regulating host inflammation to evade innate immunity remains unclear. Here, Na+/K+-ATPase beta1 subunit (ATP1B1), a pivotal antiviral protein, was shown to interact with PRRSV nsp6, a tiny viral protein encoded by ORF1a. ATP1B1 stabilized the protein level of TRAF6 by downregulating K48-linked ubiquitination of TRAF6, thus triggering NF-κB signaling and inflammatory response. Moreover, PRRSV nsp6 competetively interacted with ATP1B1 via the site of Leu 3 and impaired the formation of ATP1B1-TRAF6 complex, leading to TRAF6 proteasomal degradation and compromised inflammatory response. PRRSV with the corresponding mutation in nsp6 L3S was successfully rescued but presented defective virus growth in the late stage of infection, especially under the inflammation condition induced by either ATP1B1 overexpression or poly (I:C) stimulation. In addition, the halt in PRRSV replication was induced by treatment with autophagy inhibitor BafA1 during virus passage. L3S mutant virus impaired the recovery of virus growth even after the removal of BafA1, indicating the key role of nsp6 in sustaining virus vitality under innate immunity. Taken together, these results elucidate the functional mechanism by which PRRSV alleviates the inflammatory response to promote successful virus proliferation and growth recovery from the host innate immune response.

Viral infections trigger inflammasome-mediated caspase-1 activation. Nevertheless, limited understanding exists regarding how viruses use the active caspase-1 to evade host immune response. Here, we use porcine epidemic diarrhea virus (PEDV) as a model of coronaviruses (CoVs) to illustrate the intricate regulation of CoVs to combat IFN-I signaling and pyroptosis. Our findings demonstrate that PEDV infection stabilizes caspase-1 expression via papain-like protease PLP2's deubiquitinase activity. This stabilization of caspase-1 disrupts IFN-I signaling by cleaving RIG-I at the D189 residue. Furthermore, we demonstrate that 6-thioguanine (6TG), a PLP2 inhibitor, reverses the inhibitory effect on IFN-I signaling mediated by PLP2 and significantly reduces PEDV replication. Additionally, PLP2 degrades GSDMD-p30 by removing its K27-linked ubiquitin chain at K275 to restrain pyroptosis. Papain-like proteases from other genera of CoVs (PDCoV and SARS-CoV-2) have the similar activity to degrade GSDMD-p30. We further demonstrate that SARS-CoV-2 N protein induced NLRP3 inflammasome activation also uses the active caspase-1 to counter IFN-I signaling by cleaving RIG-I. Therefore, our work unravels a novel antagonistic mechanism employed by CoVs to evade host antiviral response.

The aim of this study was to establish a rapid method for constructing infectious clones of porcine circovirus type 2 (PCV2). In this study, we constructed circular infectious clones of PCV2 by seamless cloning technology, using the clinically isolated strain PCV2-LX as a template. Meanwhile, this method was compared with the conventional restriction-ligation approach, focusing on the in vitro circularization (self-ligation) process of the genome and the growth characteristics of rescued viruses. The results showed that this method eliminates the need to analyze and introduce restriction endonuclease sites, thus avoiding the complexities associated with traditional restriction enzyme-based cloning steps. It offers a simple and rapid operation, enabling more efficient editing of the PCV2 genome. The infectious clones constructed using this method could be successfully rescued through liposome transfection, resulting in the production of recombinant viruses that could be stably passaged. Moreover, the recombinant viruses rescued by this method exhibited enhanced proliferative capacity in PK-15 cells and 3D4/31 cells (immortalized porcine alveolar macrophages). In conclusion, this study has established a novel reverse genetics system for PCV2, providing a new strategy for the development of PCV2 genetic engineering vaccines. Additionally, it serves as a reference for the construction of infectious clones for other emerging circoviruses such as PCV3 and PCV4.

Porcine epidemic diarrhea virus (PEDV) is an enteric coronavirus that causes acute enteric disease in piglets and severely threatens the pig industry all over the world. Death domain-associated protein (DAXX) is a classical chaperone protein involved in multiple biological processes, such as cell apoptosis, transcriptional regulation, DNA damage repair, and host innate immunity. However, whether DAXX functions in the anti-PEDV innate immune responses remains unclear. In this study, we found that PEDV infection upregulated DAXX expression and induced its nucleocytoplasmic translocation in IPEC-J2 cells. Furthermore, we found that DAXX overexpression was inhibitory to PEDV replication, while downregulation of DAXX by RNA interference facilitated PEDV replication. The antiviral activity of DAXX was due to its positive effect on IFN-λ3-STAT1 signaling, as DAXX positively regulated STAT1 activation through their interaction in cytoplasm and enhancing the downstream ISG15 expression. Mutation of tryptophan at 621 to alanine in DAXX increased its abundance in the cytoplasm, leading to the upregulation of STAT1 phosphorylation and ISG15 expression. It indicated that cytoplasmic fraction of DAXX was advantageous for the STAT1-ISG15 signaling axis and PEDV inhibition. In summary, these results show that DAXX inhibits PEDV infection by increasing IFN-λ3-induced STAT1 phosphorylation and the downstream ISG15 expression.

Classical swine fever virus (CSFV) can dampen the host innate immunity by destabilizing IRF3 upon its binding with viral Npro. High mobility group box 1 (HMGB1), a non-histone nuclear protein, has diverse functions, including inflammation, innate immunity, etc., which are closely related to its cellular localization. We investigated potential mutual interactions between CSFV and HMGB1 and their effects on virus replication. We found that HMGB1 at the protein level, but not at mRNA level, was markedly reduced in CSFV-infected or Npro-expressing IPEC-J2 cells. HMGB1 in the nuclear compartment is anti-CSFV by promoting IFN-mediated innate immune response, as evidenced by overexpression of nuclear or cytoplasmic dominant HMGB1 mutant in IPEC-J2 cells stimulated with poly(I:C). However, CSFV Npro upregulates HMGB1 acetylation, a modification that promotes HMGB1 translocation into the cytoplasmic compartment where it is degraded by lysosomes. Ethyl pyruvate could downregulate HMGB1 acetylation and prevent Npro-mediated HMGB1 reduction. Inhibition of deacetylase HDAC1 with MS275 or by RNA silencing could promote Npro-mediated HMGB1 degradation. Taken together, our study elucidates the mechanism with which HMGB1 in the nuclei initiates antiviral innate immune response to suppress CSFV replication and elaborates the pathway by which CSFV uses its Npro to evade from HMGB1-mediated antiviral immunity through upregulating HMGB1 acetylation with subsequent translocation into cytoplasm for lysosomal degradation.

Contamination of meats and meat products by pathogenic microorganisms is responsible for a significant percentage of outbreaks of foodborne illness. There are also concerns over the carcinogenic potential of dietary nitrate and nitrite in processed meat products. The past few decades have seen an extensive search for novel technologies alternative to synthetic chemical preservatives to reduce the level of contamination of foods by pathogenic and spoilage microbes. This review provides a general overview of natural preservatives with potential applications in the meat industry, including phages and their endolysins, bacteriocins, microbial lipopeptides, antimicrobial peptides of plant or insect origin, and essential oils or extracts of plant origins. Instead of providing summary data from the published literature, we attempt to elaborate the challenges facing the development of novel natural preservatives as antimicrobial hurdles, taking into consideration the sharp contrast between extensive studies in this particular field and very limited industrial use. More specifically, we emphasize the great importance of having streamlined approaches and methodological guidelines in the research and development of natural preservatives so that the journey to their industrial use for safer meats and meat products could be shortened or made easier.

高校兽医实验室是从事实验教学、培养高素质技能型人才的重要基地.随着高校兽医学科快速发展,兽医实验室生物安全管理逐渐暴露出了许多问题,迫切需要建立健全高校兽医实验室生物安全管理体系,全面保障生物安全.总结了兽医实验室在生物安全管理体系建设中的经验,阐述了高校兽医实验室生物安全管理体系建设的必要性,分析了当前管理不当存在的安全漏洞,并针对此提出了应对措施,根据"1+3+3"(一套体系、三级责任制、三道防护)原则,构建兽医实验室生物安全管理体系,为高校兽医实验室生物安全管理体系建设工作提供参考.

次氯酸钠是鸡肉储藏过程中常用的消毒制剂,不规范使用可能造成残留,影响鸡肉品质并造成食品安全问题.研究使用最新的太赫兹光谱技术,针对鸡肉低温储藏前的消毒杀菌过程,本文提出了鸡肉中次氯酸钠残留的快速检测方法.采集了不同浓度浸泡处理前后的鸡胸肉的太赫兹光谱,并对光谱数据进行处理.结果显示,在1.25 THz附近发现了次氯酸钠的特征峰,可以用于对次氯酸钠残留进行定性定量分析.根据吸收峰强度,建立了吸收峰与不同浓度次氯酸钠之间的线性关系,相关系数高达0.97.结果证明,太赫兹光谱技术可以替代传统方法,用于鸡肉中次氯酸钠残留的快速检测.

ABSTRACT Classical swine fever virus (CSFV) poses a major threat to the pig industry. The mechanisms that CSFV uses to evade host innate immunity are not fully understood. Acetylation of histones and non-histone proteins is involved in modulating innate immune responses. Histone deacetylase 1 (HDAC1) could be proviral or antiviral by modulating the acetylation status of histones, viral proteins or non-histone host proteins, depending on the type of viruses involved. First, we found that CSFV infection in IPEC-J2 cells resulted in reduced expression of HDAC1. By chemical inhibition, gene silencing, and overexpression, we revealed that HDAC1 acts as a negative regulator of CSFV replication in IPEC-J2 cells probably through activation of poly(I:C) and IFN-λ3-induced IFN-I/III innate immunity. Mechanistically, CSFV N pro downregulated HDAC1 and its transcriptional regulator specificity protein 1 (Sp1). N pro interacted with Sp1 to facilitate its degradation through the ubiquitin-proteasome pathway via its N-terminal domain, a region that does not have significant effect on IRF3 stability. Thus, it is clear that CSFV deploys the two domains of its N pro to counteract the innate immune responses, the C-terminal one targeting the IRF3 pathway as previously reported, and the N-terminal one targeting the Sp1-HDAC1 axis. IMPORTANCE Of the flaviviruses, only CSFV and bovine viral diarrhea virus express N pro as the non-structural protein which is not essential for viral replication but functions to dampen host innate immunity. We have deciphered a novel mechanism with which CSFV uses to evade the host antiviral immunity by the N-terminal domain of its N pro to facilitate proteasomal degradation of Sp1 with subsequent reduction of HDAC1 and ISG15 expression. This is distinct from earlier findings involving N pro -mediated IRF3 degradation via the C-terminal domain. This study provides insights for further studies on how HDAC1 plays its role in antiviral immunity, and if and how other viral proteins, such as the core protein of CSFV, the nucleocapsid protein of porcine epidemic diarrhea virus, or even other coronaviruses, exert antiviral immune responses via the Sp1-HDAC1 axis. Such research may lead to a deeper understanding of viral immune evasion strategies as part of their pathogenetic mechanisms.