Porcine GPX1 enhances GP5-based DNA vaccination against porcine reproductive and respiratory syndrome virus

Genome-wide identification and analysis of TMT-based proteomes in longissimus dorsi tissue from Kazakh cattle and Xinjiang brown cattle

With the gradual completion of the human genome project, proteomes have gained extremely important value in the fields of human disease and biological process research. In our previous research, we performed transcriptomic analyses of longissimus dorsi tissue from Kazakh cattle and Xinjiang brown cattle and conducted in-depth studies on the muscles of both species through epigenetics. However, it is unclear whether differentially expressed proteins in Kazakh cattle and Xinjiang brown cattle regulate muscle production and development. In this study, a proteomic analysis was performed on Xinjiang brown cattle and Kazakh cattle by using TMT markers, HPLC classification, LC/MS and bioinformatics analysis. A total of 13,078 peptides were identified, including 11,258 unique peptides. We identified a total of 1874 proteins, among which 1565 were quantifiable. Compared to Kazakh cattle, Xinjiang brown cattle exhibited 75 upregulated proteins and 44 downregulated proteins. These differentially expressed proteins were enriched for the functions of adrenergic signaling in cardiomyocytes, fatty acid degradation and glutathione metabolism. In our research, we found differentially expressed proteins in longissimus dorsi tissue between Kazakh cattle and Xinjiang brown cattle. We predict that these proteins regulate muscle production and development through select enriched signaling pathways. This study provides novel insights into the roles of proteomes in cattle genetics and breeding.

Research Progress on Glycoprotein 5 of Porcine Reproductive and Respiratory Syndrome Virus

Porcine reproductive and respiratory syndrome (PRRS) is an acute, febrile, and highly contagious disease caused by the porcine reproductive and respiratory syndrome virus (PRRSV). Glycoprotein 5 (GP5) is a glycosylated envelope protein encoded by the PRRSV ORF5, which has good immunogenicity and can induce the body to produce neutralizing antibodies. Therefore, study of GP5 protein is of great significance in the diagnosis, prevention, and control of PRRSV and the development of new vaccines. We reviewed GP5 protein genetic variation, immune function, interaction with viral protein and host proteins, induction of cell apoptosis, and stimulation of neutralizing antibodies. GP5 protein's influence on virus replication and virulence, as well as its use as a target for viral detection and immunization are reviewed.

Structural Characterization of the Helicase nsp10 Encoded by Porcine Reproductive and Respiratory Syndrome Virus

Currently, an effective therapeutic treatment for porcine reproductive and respiratory syndrome virus (PRRSV) remains elusive. PRRSV helicase nsp10 is an important component of the replication transcription complex that plays a crucial role in viral replication, making nsp10 an important target for drug development. Here, we report the first crystal structure of full-length nsp10 from the arterivirus PRRSV, which has multiple domains: an N-terminal zinc-binding domain (ZBD), a 1B domain, and helicase core domains 1A and 2A. Importantly, our structural analyses indicate that the conformation of the 1B domain from arterivirus nsp10 undergoes a dynamic transition. The polynucleotide substrate channel formed by domains 1A and 1B adopts an open state, which may create enough space to accommodate and bind double-stranded RNA (dsRNA) during unwinding. Moreover, we report a unique C-terminal domain structure that participates in stabilizing the overall helicase structure. Our biochemical experiments also showed that deletion of the 1B domain and C-terminal domain significantly reduced the helicase activity of nsp10, indicating that the four domains must cooperate to contribute to helicase function. In addition, our results indicate that nidoviruses contain a conserved helicase core domain and key amino acid sites affecting helicase function, which share a common mechanism of helicase translocation and unwinding activity. These findings will help to further our understanding of the mechanism of helicase function and provide new targets for the development of antiviral drugs.IMPORTANCE Porcine reproductive and respiratory syndrome virus (PRRSV) is a major respiratory disease agent in pigs that causes enormous economic losses to the global swine industry. PRRSV helicase nsp10 is a multifunctional protein with translocation and unwinding activities and plays a vital role in viral RNA synthesis. Here, we report the first structure of full-length nsp10 from the arterivirus PRRSV at 3.0-Å resolution. Our results show that the 1B domain of PRRSV nsp10 adopts a novel open state and has a unique C-terminal domain structure, which plays a crucial role in nsp10 helicase activity. Furthermore, mutagenesis and structural analysis revealed conservation of the helicase catalytic domain across the order Nidovirales (families Arteriviridae and Coronaviridae). Importantly, our results will provide a structural basis for further understanding the function of helicases in the order Nidovirales.

A flagellin-adjuvanted inactivated porcine epidemic diarrhea virus (PEDV) vaccine provides enhanced immune protection against PEDV challenge in piglets

Since late 2010, outbreaks of porcine epidemic diarrhea (PED) have been reported in the swine industry in China. A variant PEDV strain that differs from strain CV777 causes prevalent PEDV infections which commercial vaccines based on CV777 cannot provide complete protection. In this study, we designed a new vaccine based on the epidemic PEDV strain AH2012/12, adjuvanted with flagellin, a mucosal adjuvant that induces mucosal and systemic production of IgA. Three groups of pregnant sows were immunized twice, with a 14-day interval, with PEDV adjuvanted with flagellin, PEDV alone, or PBS before farrowing, and newborn piglets from each group were selected and challenged with PEDV. Immunization with this vaccine elicited high levels of IgG, IgA, and neutralizing antibodies in the serum and colostrum of sows, and newborn piglets were protected against PEDV while suckling. This study should guide the prevention and control strategies for PEDV infection, thereby reducing the losses associated with this virus.

GPx1-mediated DNMT1 expression is involved in the blocking effects of selenium on OTA-induced cytotoxicity and DNA damage

Ochratoxin A (OTA) is a potent nephrotoxin. Selenium (Se) is an essential micronutrient for humans and animals, and plays a key role in antioxidant defense. To date, little is known about the effect of Se on OTA-induced DNA damage. In this study, the protective effects of Se (from selenomethionine) against OTA-induced cytotoxicity and DNA damage were investigated by using PK15 cells as a model. The results showed that OTA at 4.0 μg/mL induced cytotoxicity and DNA damage. Se at 0.5, 1, 2 and 4 μM significantly blocked OTA-induced cytotoxicity and DNA damage. Furthermore, Se blocked the increases of DNMT1, DNMT3a and HDAC1 mRNA and protein expression, reversed the decreases of glutathione peroxidase 1 (GPx1) mRNA and protein expression, and promoted the increases of SOCS3 mRNA and protein expression induced by OTA. Overexpression of GPx1 by pcDNA3.1-GPx1 inhibited the OTA-induced DNMT1 expression, promoted OTA-induced SOCS3 expression, and prevented the OTA-induced cytotoxicity and DNA damage. In contrast, knock-down of GPx1 by using a GPx1-specific siRNA had the opposite effects. The results suggest that GPx1-mediated DNMT1 expression is involved in the blocking effects of selenium on OTA-induced cytotoxicity and DNA damage.

Identification of two antiviral inhibitors targeting 3C-like serine/3C-like protease of porcine reproductive and respiratory syndrome virus and porcine epidemic diarrhea virus

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Identification of antiviral inhibitors that target PRRSV nsp4 (3CLSP).

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Suppression of PRRSV replication by compounds 2, 3 and 5.

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Compounds 2 and 3 exhibit broad-spectrum antiviral activity against PEDV.

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Compounds 2 and 3 may block the combination of proteases and substrates.

Porcine reproductive and respiratory syndrome virus (PRRSV) and porcine epidemic diarrhea virus (PEDV) are highly virulent and contagious porcine pathogens that cause tremendous economic losses to the swine industry worldwide. Currently, there is no effective treatment for PRRSV and PEDV, and commercial vaccines do not induce sterilizing immunity. In this study, we screened a library of 1000 compounds and identified two specific inhibitors, designated compounds 2 and 3, which target the PRRSV 3C-like serine protease (3CLSP). First, we evaluated the inhibitory effects of compounds 2 and 3 on PRRSV 3CLSP activity. Next, we determined the anti-PRRSV capacity of compounds 2 and 3 in MARC-145 cells and obtained EC₅₀ and CC₅₀ values of 57 μM (CC₅₀ = 479.9 μM) and 56.8 μM (CC₅₀ = 482.8 μM), respectively. Importantly, compounds 2 and 3 also targeted the PEDV 3C-like protease (3CL protease) and inhibited PEDV replication, showing EC₅₀ and CC₅₀ values of 100 μM (CC₅₀ = 533.8 μM) and 57.9 μM (CC₅₀ = 522.3 μM), respectively. Finally, our results indicated that the active sites (His39 in 3CLSP and His41 in 3CL protease) were conservative, and contacted compounds 2 and 3 via hydrogen bonds and hydrophobic forces in the putative substrate-binding models. In summary, compounds 2 and 3 exhibit broad-spectrum antiviral activity and may facilitate the development of antiviral drugs against PRRSV and PEDV.

Poly (d,l-lactide-co-glycolide) nanoparticle-entrapped vaccine induces a protective immune response against porcine epidemic diarrhea virus infection in piglets

Porcine epidemic diarrhea (PED) causes 80-100% mortality in neonatal piglets, and its causative agent, the porcine epidemic diarrhea virus (PEDV), poses an important threat to the swine industry worldwide. In this study, we prepared biodegradable poly (d,l-lactide-co-glycolide) (PLGA) nanoparticle-entrapped PEDV killed vaccine antigens (KAg) (PLGA-KAg). Late-term pregnant sows were intranasally inoculated with PLGA-KAg, and the mortality resulting from challenge with highly virulent PEDV was investigated in their passively immunized suckling piglets. PEDV-specific IgG and IgA antibody titers were enhanced in pregnant sows immunized with PLGA-KAg relative to the titers in sows inoculated with KAg. Similar results were seen in the passively immunized suckling piglets of these sows. Improved lymphocyte proliferation responses and IFN-γ levels were induced in pregnant sows immunized with PLGA-KAg compared with those vaccinated with KAg or with Montanide™ ISA 201 VG emulsified killed PEDV vaccine (201-KAg). Importantly, there was less piglet mortality in the group vaccinated with PLGA-KAg than in the groups vaccinated with KAg or 201-KAg. These results demonstrate that PLGA-KAg is a promising candidate vaccine that can provide protective immunity against PEDV infection in suckling piglets.

Complete Genome Sequence of a Novel Subgenotype of Porcine Reproductive and Respiratory Syndrome Virus Strain JX/CH/2016, Isolated in Jiangxi, China

We sequenced the complete genome of porcine reproductive and respiratory syndrome virus (PRRSV) strain JX/CH/2016. Phylogenetic analysis based on the sequences of the open reading frame 5 (ORF5) gene revealed that this strain belongs to subgenotype IV. This is the first report of the complete genome sequence of PRRSV-IV.