To investigate the mechanism of the major capsid protein VP5 (encoded by the UL19 gene) of oncolytic herpes simplex virus type Ⅱ (oHSV2) in regulating the antitumor function of immune cells, we constructed a mouse breast cancer cell line 4T1-iRFP-VP5-GFP stably expressing VP5 protein, near-infrared fluorescent protein (iRFP), and green fluorescent protein (GFP) by using the PiggyBac transposon system. Flow cytometry and Western blotting were employed to screen the monoclonal cell lines expressing both GFP and VP5 and examine the expression stability of UL19 in the constructed cell line. The results of SYBR Green I real-time PCR and Western blotting showed that the copies of UL19 and the expression level of VP5 protein in the 15th passage of 4T1-iRFP-VP5-GFP cells were significantly higher than those in the 4T1 cells transiently transfected with UL19, demonstrating the stable insertion of UL19 into the 4T1 cell genome. The real-time cell analysis (RTCA) was employed to monitor the proliferation of 4T1-iRFP-VP5-GFP cells, which showed similar proliferation activity to their parental 4T1 cells. Further studies confirmed that NK92 cells exhibited stronger cytotoxicity against 4T1-iRFP-VP5-GFP cells than against 4T1 cells. This study layed a foundation for elucidating the role of VP5 protein in regulating immune cells, including T cells and NK cells, via HLA-E in 4T1 cells to exert the anti-tumor function.
Animals ; Mice ; DNA Transposable Elements/genetics* ; Cell Line, Tumor ; Capsid Proteins/biosynthesis* ; Transfection ; Green Fluorescent Proteins/metabolism* ; Oncolytic Viruses/genetics* ; Female ; Simplexvirus/genetics*

Endosomal sorting complex required for transport (ESCRT) system drives various cellular processes, including endosome sorting, organelle biogenesis, vesicle transport, maintenance of plasma membrane integrity, membrane fission during cytokinesis, nuclear membrane reformation after mitosis, closure of autophagic vacuoles, and enveloped virus budding. Increasing evidence suggests that the ESCRT system can be hijacked by different family viruses for their proliferation. At different stages of the virus life cycle, viruses can interfere with or exploit ESCRT-mediated physiological processes in various ways to maximize their chance of infecting the host. In addition, many retroviral and RNA viral proteins possess "late domain" motifs, which can recruit host ESCRT subunit proteins to assist in virus endocytosis, transport, replicate, budding and efflux. Therefore, the "late domain" motifs of viruses and ESCRT subunit proteins could serve as promising drug targets in antiviral therapy. This review focuses on the composition and functions of the ESCRT system, the effects of ESCRT subunits and virus "late domain" motifs on viral replication, and the antiviral effects mediated by the ESCRT system, aiming to provide a reference for the development and utilization of antiviral drugs.
Endosomal Sorting Complexes Required for Transport/metabolism* ; Viruses/metabolism* ; Protein Transport ; Virus Replication ; Endosomes/metabolism* ; Virus Release

N⁶-methyladenine (m⁶A) is the most abundant RNA modification in mammalian messenger RNAs (mRNAs), which participates in and regulates many important biological activities, such as tissue development and stem cell differentiation. Due to an improved understanding of m⁶A, researchers have discovered that the biological function of m⁶A can be linked to many stages of mRNA metabolism and that m⁶A can regulate a variety of complex biological processes. In addition to its location on mammalian mRNAs, m⁶A has been identified on viral transcripts. m⁶A also plays important roles in the life cycle of many viruses and in viral replication in host cells. In this review, we briefly introduce the detection methods of m⁶A, the m⁶A-related proteins, and the functions of m⁶A. We also summarize the effects of m⁶A-related proteins on viral replication and infection. We hope that this review provides researchers with some insights for elucidating the complex mechanisms of the epitranscriptome related to viruses, and provides information for further study of the mechanisms of other modified nucleobases acting on processes such as viral replication. We also anticipate that this review can stimulate collaborative research from different fields, such as chemistry, biology, and medicine, and promote the development of antiviral drugs and vaccines.
Animals ; Viruses/genetics* ; RNA, Messenger/metabolism* ; Adenosine/metabolism* ; Cell Differentiation ; Mammals/metabolism*

Emerging and re-emerging RNA viruses occasionally cause epidemics and pandemics worldwide, such as the on-going outbreak of the novel coronavirus SARS-CoV-2. Herein, we identified two potent inhibitors of human DHODH, S312 and S416, with favorable drug-likeness and pharmacokinetic profiles, which all showed broad-spectrum antiviral effects against various RNA viruses, including influenza A virus, Zika virus, Ebola virus, and particularly against SARS-CoV-2. Notably, S416 is reported to be the most potent inhibitor so far with an EC of 17 nmol/L and an SI value of 10,505.88 in infected cells. Our results are the first to validate that DHODH is an attractive host target through high antiviral efficacy in vivo and low virus replication in DHODH knock-out cells. This work demonstrates that both S312/S416 and old drugs (Leflunomide/Teriflunomide) with dual actions of antiviral and immuno-regulation may have clinical potentials to cure SARS-CoV-2 or other RNA viruses circulating worldwide, no matter such viruses are mutated or not.
Animals ; Antiviral Agents ; pharmacology ; therapeutic use ; Betacoronavirus ; drug effects ; physiology ; Binding Sites ; drug effects ; Cell Line ; Coronavirus Infections ; drug therapy ; virology ; Crotonates ; pharmacology ; Cytokine Release Syndrome ; drug therapy ; Drug Evaluation, Preclinical ; Gene Knockout Techniques ; Humans ; Influenza A virus ; drug effects ; Leflunomide ; pharmacology ; Mice ; Mice, Inbred BALB C ; Orthomyxoviridae Infections ; drug therapy ; Oseltamivir ; therapeutic use ; Oxidoreductases ; antagonists & inhibitors ; metabolism ; Pandemics ; Pneumonia, Viral ; drug therapy ; virology ; Protein Binding ; drug effects ; Pyrimidines ; biosynthesis ; RNA Viruses ; drug effects ; physiology ; Structure-Activity Relationship ; Toluidines ; pharmacology ; Ubiquinone ; metabolism ; Virus Replication ; drug effects

The respiratory syncytial virus (RSV) is one of the most common causes of acute infection of the lower respiratory tract among children. For viruses in the Paramyxoviridae subfamily, membrane fusion requires a specific interaction between two glycoproteins: the fusion protein and attachment protein. Membrane fusion of the RSV appears to be unique among paramyxoviruses in that fusion is accomplished by the fusion protein alone without help from the attachment protein. Here, we review recent achievements and advances in the study of membrane fusion triggered by the RSV published in high-impact-factor journals. We also review and make a comparative analysis of the popular hypotheses regarding membrane fusion of the RSV. Finally, we discuss the "hot topics" in current research and controversial data published in recent years in the hope of providing references for Chinese researchers.
Animals ; Humans ; Respiratory Syncytial Virus Infections ; virology ; Respiratory Syncytial Viruses ; genetics ; physiology ; Viral Fusion Proteins ; genetics ; metabolism ; Virus Internalization

MicroRNA (miRNA) are small non-coding molecules of ribonucleic acid. They are about 22 nucleotides in length, single-stranded, and mediate post-translational regulation by the repression or degradation of messenger RNA(mRNA). miRNA play a key part in the proliferation, differentiation and death of cells. Viral infection is one of the most common causes of human disease. Some studies have found that miRNA has a very close relationship with viral infection, which has an effect on viral replication, the immune response and antiviral immunity. Use of miRNA may become the cornerstone of new methods for the diagnosis and treatment of viral infection. This article summarizes the progress of research into miRNA and viral infection.
Animals ; Humans ; MicroRNAs ; genetics ; metabolism ; Virus Diseases ; genetics ; metabolism ; virology ; Virus Physiological Phenomena ; Virus Replication ; Viruses ; genetics

OBJECTIVES: An outbreak of acute febrile illness occurred in the Republic of Korea Air Force boot camp from May to July 2011. An epidemiological investigation of the causative agent, which was of a highly infective nature, was conducted. METHODS: Throat swabs were carried out and a multiplex reverse transcriptase-polymerase chain reaction (RT-PCR) assay was performed to identify possible causative factors. RESULTS: The mean age of patients who had febrile illness during the study period was 20.24 years. The multiplex RT-PCR assay identified respiratory syncytial virus (RSV) as the causative agent. The main symptoms were sore throat (76.0%), sputum (72.8%), cough (72.1%), tonsillar hypertrophy (67.9%), and rhinorrhea (55.9%). The mean temperature was 38.75degreesC and the attack rate among the recruits was 15.7% (588 out of 3750 recruits), while the mean duration of fever was 2.3 days. The prognosis was generally favorable with supportive care but recurrent fever occurred in 10.1% of the patients within a month. CONCLUSIONS: This is the first epidemiological study of an RSV outbreak that developed in a healthy young adult group. In the event of an outbreak of an acute febrile illness of a highly infective nature in facilities used by a young adult group, RSV should be considered among the possible causative agents.
Adolescent ; Adult ; Antiviral Agents/therapeutic use ; Body Temperature ; Disease Outbreaks ; Humans ; Male ; Military Personnel ; Multiplex Polymerase Chain Reaction ; Oseltamivir/therapeutic use ; Pharynx/virology ; RNA, Viral/chemistry/genetics/metabolism ; Republic of Korea/epidemiology ; Respiratory Syncytial Virus Infections/drug therapy/*epidemiology/virology ; Respiratory Syncytial Viruses/*genetics/isolation & purification ; Sputum/virology ; Young Adult

OBJECTIVETo investigate the regulation trend of Jinxin Oral Liquid (JXOL) on the expression of negative regulatory factor of TLR3 signaling pathway SOCS1 in the lung tissue of RSV infected BALB/c mice at different time points.

METHODSTotally 75 BALB/c mice were randomly divided into 5 groups, i.e., the normal control group, the model group, the ribavirin group, the high dose JXOL group, and the equivalent dose JXOL group, 15 in each group. Each group had 3 intervention ways (I, II, and III) with 5 mice treated in each group. BALB/c mice were nasally infected with respiratory syncytial virus (RSV), and treated by different intervention ways. After intervention, mice were killed and their lung tissues were sampled, mRNA expression levels of RSV-M, SOCS1, and IFN-β were detected by Real time PCR. The expression of SOCSl at the protein level was detected by Western blot.

RESULTSCompared with the normal control group, the mRNA expression level of SOCS1 and IFN-β, and the protein expression level of SOCS1 increased significantly in the model group intervened by intervention I and II (all P < 0.01), but the mRNA expression level of IFN-β decreased significantly in model group intervened by intervention III (P < 0.01). Compared with the model group, the mRNA expression level of RSV-M all significantly decreased in the high dose JXOL group and the equivalent dose JXOL group intervened by 3 intervention ways (all P < 0.01). The mRNA expression level of SOCS1 significantly decreased in the high dose JXOL group intervened by intervention I and III and the equivalent dose JXOL group intervened by 3 intervention ways (all P < 0.01). The mRNA expression level of IFN-β significantly decreased in the high dose JXOL group intervened by intervention I and II and the equivalent dose JXOL group intervened by intervention I (all P < 0.01), while it significantly increased in the high dose JXOL group intervened by intervention III and the equivalent dose JXOL group intervened by intervention III (all P < 0.01). The protein expression level of SOCS1 significantly decreased in the high dose JXOL group intervened by intervention I and the equivalent dose JXOL group intervened by 3 intervention ways (all P < 0.01), while it significantly increased in the high dose JXOL group intervened by intervention III (all P < 0.01). Compared with the high dose JXOL group, the mRNA expression level of RSV-M decreased significantly in the equivalent dose JXOL group intervened by intervention I and II (P < 0.01). The mRNA expression level of SOCS1 and IFN-β decreased significantly in the equivalent dose JXOL group intervened by intervention I (P < 0.01), but the mRNA expression level of IFN-β increased significantly in the equivalent dose JXOL group intervened by intervention II and III (all P < 0.01). The protein expression level of SOCS1 decreased significantly in the equivalent dose JXOL group intervened by 3 intervention ways (all P < 0.01).

CONCLUSIONSJXOL could inhibit the expression of SOCS1 in the lung tissue of RSV infected BALB/c mice at different time points. Its regulatory effect might be associated with promoting the expression of interferon type I and further fighting against RSV.

Animals ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Lung ; metabolism ; Mice ; Mice, Inbred BALB C ; RNA, Messenger ; Respiratory Syncytial Virus Infections ; drug therapy ; metabolism ; Respiratory Syncytial Viruses ; Ribavirin ; Signal Transduction ; Suppressor of Cytokine Signaling 1 Protein ; Suppressor of Cytokine Signaling Proteins ; metabolism ; Toll-Like Receptor 3 ; metabolism

OBJECTIVETo explore the anti-tumor effect and its mechanism of Sendai virus Tianjin strain defective interfering particles (DIP) on mouse models of colon carcinoma.

METHODSCT26 cells (5×10(6)/0.1 ml) were subcutaneously injected into the back of Bal B/c mice to establish murine colon carcinoma model. After the tumors reached 5 mm in diameter, the mice were randomly divided into Tianjin strain DIP group and saline control group. The former was intratumorally injected with Tianjin strain DIP (0.1 ml) once a day on day 4, 7, 10 and 13 after CT26 cell inoculation. The latter was intratumorally injected with the same volume of saline. Tumor volume and survival rate of the mice were calculated to confirm the anti-tumor effect of DIP. Flow cytometry and ELISA were used to examine the maturation and release of cytokines IL-6, IFN-α and TNF-α from murine myeloid dendritic cells (DCs) induced by Tianjin strain DIP. Moreover, real-time RT-PCR and immunohistochemistry were performed to identify whether the Tianjin strain DIP could induce infiltration of CD11c(+) DCs, CD4(+) and CD8(+) T cells in the tumors.

RESULTSOn day 22 after CT26 cell inoculation, the average tumor volume of the Tianjin strain DIP group was (33.2 ± 2.0) mm(3), significantly smaller than that of the control group [(2 376.0 ± 130.8)mm(3), P < 0.01]. On day 50 after CT26 cell inoculation, the survival rate of mice was 90.0% in the Tianjin strain DIP group, much higher than that of the control group (30.0%, P < 0.01). Flow cytometry analysis showed that the expression of markers of DCs maturation, including CD40, CD80 and CD86, was dose-dependently increased by DIP or intact virus. No statistically significant difference was found betweent the DIP and intact virus groups. ELISA results showed that DIP could stimulate the secretion of IL-6, IFN-α and TNF-α from mouse DCs. The secretion of all of the cytokines was dose-dependently increased by DIP or intact virus. Real-time RT-PCR revealed that the expression of CD4, CD8 and CD11c mRNAs was increased in tumors treated with DIP compared with that of the saline group at all time points. Moreover, the expression level of all of them remained maximal at 120 h after the last treatment. Immunohistochemical staining revealed that the ratios of CD4(+), CD8(+) T cells or CD11c(+) DCs to total cells were (21.60 ± 1.49)%, (22.12 ± 2.84)% and (23.05 ± 2.91)%, respectively, in the DIP-treated tumors. In the tumors treated by saline, the ratios were (2.62 ± 0.60)%, (4.05 ± 0.12)% and (3.10 ± 0.09)%, respectively. The difference between experimental group and control group had statistical significance.

CONCLUSIONSTianjin strain DIP may exert anti-tumor effect on tumor-bearing mice. The mechanism is related with the antitumor immunity induced by DCs and T cells.

Animals ; Cell Line, Tumor ; Colonic Neoplasms ; metabolism ; pathology ; Cytokines ; metabolism ; Defective Viruses ; immunology ; Dendritic Cells ; metabolism ; Female ; Interferon-alpha ; metabolism ; Interleukin-6 ; metabolism ; Mice ; Mice, Inbred BALB C ; Neoplasm Transplantation ; Random Allocation ; Sendai virus ; immunology ; T-Lymphocytes ; metabolism ; Tumor Burden ; Tumor Necrosis Factor-alpha ; metabolism

During virus infection, viral RNAs and mRNAs function as blueprints for viral protein synthesis and possibly as pathogen-associated molecular patterns (PAMPs) in innate immunity. Here, considering recent research progress in microRNAs (miRNAs) and competitive endogenous RNAs (ceRNAs), we speculate that viral RNAs act as sponges and can sequester endogenous miRNAs within infected cells, thus cross-regulating the stability and translational efficiency of host mRNAs with shared miRNA response elements. This cross-talk and these reciprocal interactions between viral RNAs and host mRNAs are termed "competitive viral and host RNAs" (cvhRNAs). We further provide recent experimental evidence for the existence of cvhRNAs networks in hepatitis B virus (HBV), as well as Herpesvirus saimiri (HVS), lytic murine cytomegalovirus (MCMV) and human cytomegalovirus (HCMV) infections. In addition, the cvhRNA hypothesis also predicts possible cross-regulation between host and other viruses, such as hepatitis C virus (HCV), HIV, influenza virus, human papillomaviruses (HPV). Since the interaction between miRNAs and viral RNAs also inevitably leads to repression of viral RNA function, we speculate that virus may evolve either to employ cvhRNA networks or to avoid miRNA targeting for optimal fitness within the host. CvhRNA networks may therefore play a fundamental role in the regulation of viral replication, infection establishment, and viral pathogenesis.
Animals ; DNA Viruses ; genetics ; physiology ; Host-Pathogen Interactions ; physiology ; Humans ; MicroRNAs ; metabolism ; RNA Viruses ; genetics ; physiology ; RNA, Messenger ; metabolism ; RNA, Viral ; metabolism ; Virus Diseases ; immunology ; physiopathology ; virology ; Virus Replication