The Competitive Endogenous RNA (ceRNA) Regulation in Porcine Alveolar Macrophages (3D4/21) Infected by Swine Influenza Virus (H1N1 and H3N2)

CD46 inhibits the replication of swine influenza viruses by promoting the production of type I IFNs in PK-15 cells

Swine flu caused by swine influenza A virus (swIAV) is an acute respiratory viral disease that is spreading in swine herds worldwide. Although the effect of some host factors on replication of swIAV has been identified, the role of CD46 in this process is unclear. Here, we report that CD46 inhibits the replication of swIAV by promoting the production of type I interferons (IFNs) in porcine kidney (PK-15) cells. CD46 knockout (CD46-KO) and stably expressing (CD46-overexpression) PK-15 cells were prepared using lentivirus-mediated CRISPR/Cas9 gene editing and seamless cloning technology. The results of virus infection in CD46-overexpression PK-15 cells showed that the replication of H1N1 and H3N2 swIAVs were inhibited, and the production of type I IFNs (IFN-α, IFN-β), interferon regulatory factor (IRF) 3, and mitochondrial antiviral-signaling protein (MAVS) was enhanced. Virus infection in CD46-KO PK-15 cells showed the opposite results. Further results showed that CD46-KO PK-15 cells have a favorable ability to proliferate influenza viruses compared to Madin-Darby canine kidney (MDCK) and PK-15 cells. These findings indicate that CD46 acts as promising target regulating the replication of swIAV, and help to develop new agents against infection and replication of the virus.

Advances in the understanding of circRNAs that influence viral replication in host cells

Circular RNAs (circRNAs) are non-coding RNAs discovered in recent years, which are produced by back-splicing involving the 3' and 5' ends of RNA molecules. There is increasing evidence that circRNAs have important roles in cancer, neurological diseases, cardiovascular and cerebrovascular diseases, and other diseases. In addition, host circRNAs and virus-encoded circRNAs participate in the body's immune response, with antiviral roles. This review summarizes the mechanisms by which host and viral circRNAs interact during the host immune response. Comprehensive investigations have revealed that host circRNAs function as miRNA sponges in a particular manner, primarily by inhibiting viral replication. Viral circRNAs have more diverse functions, which generally involve promoting viral replication. In addition, in contrast to circRNAs from RNA viruses, circRNAs from DNA viruses can influence host cell migration, proliferation, and apoptosis, along with their effects on viral replication. In summary, circRNAs have potential as diagnostic and therapeutic targets, offering a foundation for the diagnosis and treatment of viral diseases.

A replicative recombinant HPV16 E7 expression virus upregulates CD36 in C33A cells

Objective

In past decades, the role of high-risk HPV (HR-HPV) infection in cancer pathogenesis has been extensively studied. The viral E7 protein expressed in pre-malignant cells has been identified as an ideal target for immunological intervention. However, the cultivation of HPV in vitro remains a significant challenge, as well as the lack of methods for expressing the HPV E7 protein and generating replication-competent recombinant viral particles, which posed a major obstacle to further exploration of the function and carcinogenic mechanisms of the E7 oncoprotein. Therefore, it is imperative to investigate novel methodologies to construct replication-competent recombinant viral particles that express the HPV E7 protein to facilitate the study of its function.

Methods

We initiated the construction of recombinant viral particles by utilizing the ccdB-Kan forward/reverse screening system in conjunction with the Red/ExoCET recombinant system. We followed the infection of C33A cells with the obtained recombinant virus to enable the continuous expression of HPV16 E7. Afterwards, the total RNA was extracted and performed transcriptome sequencing using RNA-Seq technology to identify differentially expressed genes associated with HPV-induced oncogenicity.

Results

We successfully established replicative recombinant viral particles expressing HPV16 E7 stably and continuously. The C33A cells were infected with recombinant viral particles to achieve overexpression of the E7 protein. Subsequently, RNA-Seq analysis was conducted to assess the changes in host cell gene expression. The results revealed an upregulation of the CD36 gene, which is associated with the HPV-induced oncogenic pathways, including PI3K-Akt and p53 signaling pathway. qRT-PCR analysis further identified that the upregulation of the CD36 gene due to the expression of HPV16 E7.

Conclusion

The successful expression of HPV16 E7 in cells demonstrates that the replicated recombinant virus retains the replication and infection abilities of Ad4, while also upregulating the CD36 gene involved in the PI3K-Akt signaling and p53 pathways, thereby promoting cell proliferation. The outcome of this study provides a novel perspective and serves as a solid foundation for further exploration of HPV-related carcinogenesis and the development of replicative HPV recombinant vaccines capable of inducing protective immunity against HPV.

Transcriptome-Wide lncRNA and mRNA Profiling of Spleens from Meishan Pigs at Different Development Stages

Simple Summary

Meishan pig is a local pig breed in China, which has higher immunity than commercial pig breeds for some diseases. The spleen has hematopoietic and immune response functions, making it a good organ model for studying immunity. We depicted the expression profiles of lncRNA-mRNA in the spleen of Meishan pigs at different developmental time points (7 d, 21 d, 35 d, 120 d and 180 d). In addition, we found that AKT3, CBL and PTK2B may be involved in immune regulation in Meishan pigs through a competing endogenous RNA network. This result provides valuable genomic resources for studying immune regulation in animals and finds potential molecular markers for pig disease resistance breeding.

Abstract

Meishan is a well-established local Chinese breed known for its high fecundity, strong immune response and high meat quality. However, the molecular mechanism of immune regulation during the development of Meishan pigs still remains unclear. Here, we performed the transcriptional sequencing of spleen tissues from Meishan pigs at different development stages. In total, 10,268 lncRNAs were identified, including 1254 novel lncRNAs and 9014 known lncRNAs. Time series analysis revealed that genes of the up-regulated module were enriched in pathways associated with transport, immunity, and histone acetylation modifications, while genes of the down-regulated module were enriched in DNA metabolic process and cell cycle. Weighted gene co-expression network analysis (WGCNA) showed the functional linkage between mRNAs and lncRNAs, indicating that lncRNAs are important regulatory elements of mRNAs. Notably, a lncRNA-miRNA-mRNA competing endogenous RNA (ceRNA) network that contained 3 mRNAs (AKT3, CBL and PTK2B), 17 lncRNAs and 67 miRNAs were screened out, which probably plays a critical role in immune regulation of Meishan pigs. Our findings not only revealed the transcriptome profile of spleen development, but also provide novel insights into the mechanism of lncRNA-miRNA-mRNA axis in the immune response in Meishan pigs.

Effects of swine microRNA mimics on lipopolysaccharide (LPS) induced inflammatory changes in 3D4/21 cells

There have been limited studies focused on validation of swine microRNAs (miRNA) with mRNA targets. The objective of this study was to validate a defined set of targets using artificial miRNA mimics transfected into cell lines to confirm specific targets of endogenous miRNAs after administration of Escherichia coli lipopolysaccharide (LPS). Sixteen hours after mimic transfection of 3D4/21 cell lines, the cells were stimulated with 1 μg/ml LPS or phosphate-buffered saline (PBS). The cells were harvested and collected at 0, 1, 3, and 8 h post administration. The selected genes DAD1, IL8, and ESR, which are involved in known pathways of inflammation. and are predicted or validated human targets of either miR-146a, let-7a, or miR-22-3p. These were then evaluated by quantitative real-time-PCR (qRT-PCR) to verify microRNA-mRNA interaction in swine. Using the ROX reference dye, mRNA changes in expression were assessed using the comparative CT Method (ΔΔCT method) for normalization against the PBS control group. DAD1 and ESR1 were negatively regulated by miR-22-3p and miR-146a-5p, respectively in 3D4/21 cells after LPS stimulation. However, miR-146a-5p may play an indirect positive regulatory role of both DAD1 and IL8 mRNA expression. Furthermore, we found an inverse relationship between LPS stimulation compared with the let-7a-5p overexpression with DAD1. Our inflammation study provides new evidence on the roles and predicted targets of miR-146a, let-7a, and miR-22-3p in swine.