Graphene Oxide Nanoparticles Combined with CRISPR/Cas9 System Enable Efficient Inhibition of Pseudorabies Virus.

We describe an application where graphene oxide nanoparticles (GONs) enable combined inhibition of Pseudorabies Virus (PRV) through delivery of a CRISPR/Cas9 system for targeted cleaving of a PRV genome and direct interaction with viral particles. The sheeted GONs could load CRISPR plasmid DNA (pDNA) to form a small sized, near-spheroidal GONs-CRISPR complex, which enables CRISPR pDNA efficient intracellular delivery and transient expression under serum conditions. Cell studies showed that GONs-CRISPR could allow rapid cellular uptake, endolysosomes escape, and nucleus transport within 3 h. Virus studies demonstrated that the pure GONs have antiviral activity and GONs-CRISPR could significantly inhibit PRV replication and result in progeny PRV decreasing by approximately 4000 times in infected host cells. Transmission electron microscopy (TEM) imaging showed that GONs-CRISPR could destroy the PRV structures by directly interacting with viral particles. This GONs-based strategy may extend the advanced application of the CRISPR system for antiviral action.

Host-virus interactions in PK-15 cells infected with Pseudorabies virus Becker strain based on RNA-seq.

Pseudorabies is a highly contagious viral disease caused by the pseudorabies virus (PRV), and it is one of the most devastating diseases for the swine industry worldwide. However, the host-virus interaction and virus-related host factors at the mRNA level in virus natural host (pig) cells, are not fully understood. Here, we performed time-course RNA sequencing of the PK-15 cells infected with a recombinant strain PRV-Becker-GFP to study the dynamic competition between the host and the virus. At early stage of infection (3 hpi), our results suggested that the activation of cytosolic DNA-sensing pathway and NOD-like receptor signaling pathway might play a role in recognition of PRV, and the activation of NF-kappa B signaling pathway and TNF signaling pathway might be involved in immune response against the virus. However, all these pathways were subsequently inhibited by PRV. Additionally, our data indicated the fatty acid degradation pathway was significantly downregulated during late stage of infection (9 hpi), which was likely to accumulate fatty acids for viral envelope synthesis. Moreover, we verified the expression of 5 representative genes (ALDH1B1, ACAA2, ACSL3, ADH5, and EHHADH) related to fatty acid degradation pathway by RT-qPCR. Overall, our findings provide valuable information to better understand host-virus interactions and the immune escape mechanism of PRV-Becker as a virulent strain, offering novel targets for porcine anti-PRV breeding research and potential clinical treatment.

Genome-wide CRISPR/Cas9 screen identifies host factors important for porcine reproductive and respiratory syndrome virus replication.

Porcine reproductive and respiratory syndrome (PRRS), a viral infection caused by PRRS virus (PRRSV) can result in severe reproductive failure, and respiratory disease in the pigs thus causing enormous economic losses to the global swine industry. Although the cellular receptors for PRRSV have been identified, but mechanisms underlying PPRSV replication remain obscure. Here, we have performed a genome-scale CRISPR/Cas9 knockout screen in the pig kidney cells with PRRSV. Several genes were found to be highly enriched post-PRRSV selection, just like KxDL Motif Containing 1(KXD1), Proteasome 26S Subunit, Non-ATPase 3 (PSMD3) and Galectin 2 (LGALS2) and soon on. Importantly, we have identified that loss of KXD1 resulted in the restricted autophagy and inhibited replication of PRRSV. Therefore, our study demonstrates that CRISPR/Cas9 system can be effectively used for the screening of pig factors responsible for PRRSV replication.

Quercetin as an antiviral agent inhibits the Pseudorabies virus in vitro and in vivo.

Pseudorabies virus (PRV) accounts for a critical swine disease incurring economic losses worldwide. Several PRV vaccines are commercially available but these vaccines are effective against only certain prevalent PRV strains in China. To prevent PRV-induced latent infection and decrease the pathogenicity, novel anti-PRV drugs are required to prevent PRV infection. Natural products show exceptional structural diversity representing an important source for developing novel therapeutic agents. Quercetin is a flavonoid with anti-oxidant, anti-cancer, anti-bacterial and anti-viral activities. This study involved quercetin for studying the anti-PRV function in vitro and in vivo. Quercetin was found to significantly decrease the PRV virulent strain HNX at a half-maximal inhibitory concentration (IC50) of 2.618 µM and selectivity index 229. This anti-PRV activity of quercetin was found to be dose-dependent. Furthermore, quercetin also inhibited a wide the infections by a spectrum of PRV strains like HNX, Ea, Bartha and Fa strain. These virucidal effects of quercetin suggest the interaction between these molecules and viral particles, and quercetin is responsible for inhibiting the adsorption of PRV infections. The silico assays suggesting that quercetin might interact with the gD-protein on the surface of the PRV important for viral infection. Additional, the quercetin plantar injection protected the mice from the lethal challenge, decreasing the PRV-infected mice's brain viral loads and mortality. These results provides a anti-PRV strategy and contribute to drug discovery and development.

Differences in small noncoding RNAs profile between bull X and Y sperm.

The differences in small noncoding RNAs (sncRNAs), including miRNAs, piRNAs, and tRNA-derived fragments (tsRNAs), between X and Y sperm of mammals remain unclear. Here, we employed high-throughput sequencing to systematically compare the sncRNA profiles of X and Y sperm from bulls (n = 3), which may have a wider implication for the whole mammalian class. For the comparison of miRNA profiles, we found that the abundance of bta-miR-652 and bta-miR-378 were significantly higher in X sperm, while nine miRNAs, including bta-miR-204 and bta-miR-3432a, had greater abundance in Y sperm (p < 0.05). qPCR was then used to further validate their abundances. Subsequent functional analysis revealed that their targeted genes in sperm were significantly involved in nucleosome binding and nucleosomal DNA binding. In contrast, their targeted genes in mature oocyte were significantly enriched in 11 catabolic processes, indicating that these differentially abundant miRNAs may trigger a series of catabolic processes for the catabolization of different X and Y sperm components during fertilization. Furthermore, we found that X and Y sperm showed differences in piRNA clusters distributed in the genome as well as piRNA and tsRNA abundance, two tsRNAs (tRNA-Ser-AGA and tRNA-Ser-TGA) had lower abundance in X sperm than Y sperm (p < 0.05). Overall, our work describes the different sncRNA profiles of X and Y sperm in cattle and enhances our understanding of their potential roles in the regulation of sex differences in sperm and early embryonic development.

Cryopreservation Induces Alterations of miRNA and mRNA Fragment Profiles of Bull Sperm.

Although cryopreservation of bull semen is widely used commercially in the livestock breeding industry, cryopreservation results in low fertility of bull sperm. As an important regulatory factor, the alteration of small non-coding RNA (sncRNA) profile during cryopreservation of bull sperm is not yet completely known. In the present study, we sequenced sncRNAs of frozen and fresh sperm to study the link of alteration of the sncRNA profiles (particularly in miRNAs and mRNA fragments) with low sperm fertility caused by cryopreservation. We identified 55 miRNAs and 526 mRNA fragments differentially expressed (DE) between frozen and fresh sperm. Subsequently, the functional analysis revealed that targeted genes of DE miRNAs in sperm had roles in the fertilization, ATP, and apoptosis. Instead, targeted genes of DE miRNAs in cow metaphase II oocyte were significantly enriched in the MAPK signaling pathway, autophagy-animal pathway, and mitophagy-animal pathway. Additionally, biological processes of DNA repair, spermatid development, response to temperature stimulus, and cellular response to DNA damage stimulus were enriched by mRNA fragments. In conclusion, we found that DE miRNAs or DE mRNA fragments in cryopreservation may influence the fertility of sperm, these findings will provide the reference to improve the cryopreservation technology of bull semen.