The present study delves into the cellular mechanisms underlying the antiviral effects of dehydrodiisoeugenol(DEH) by focusing on the transcription factor EB(TFEB)/autophagy-lysosome pathway. The cell counting kit-8(CCK-8) was utilized to assess the impact of DEH on the viability of human non-small cell lung cancer cells(A549). The inhibitory effect of DEH on the replication of influenza A virus(H1N1) was determined by real-time quantitative polymerase chain reaction(RT-qPCR). Western blot was employed to evaluate the influence of DEH on the expression level of the H1N1 virus nucleoprotein(NP). The effect of DEH on the fluorescence intensity of NP was examined by the immunofluorescence assay. A mouse model of H1N1 virus infection was established via nasal inhalation to evaluate the therapeutic efficacy of 30 mg·kg~(-1) DEH on H1N1 virus infection. RNA sequencing(RNA-seq) was performed for the transcriptional profiling of mouse embryonic fibroblasts(MEFs) in response to DEH. The fluorescent protein-tagged microtubule-associated protein 1 light chain 3(LC3) was used to assess the autophagy induced by DEH. Western blot was employed to determine the effect of DEH on the autophagy flux of LC3Ⅱ/LC3Ⅰ under viral infection conditions. Lastly, the role of TFEB expression in the inhibition of DEH against H1N1 infection was evaluated in immortalized bone marrow-derived macrophage(iBMDM), both wild-type and TFEB knockout. The results revealed that the half-maximal inhibitory concentration(IC_(50)) of DEH for A549 cells was(87.17±0.247)μmol·L~(-1), and DEH inhibited H1N1 virus replication in a dose-dependent manner in vitro. Compared with the H1N1 virus-infected mouse model, the treatment with DEH significantly improved the body weights and survival time of mice. DEH induced LC3 aggregation, and the absence of TFEB expression in iBMDM markedly limited the ability of DEH to counteract H1N1 virus replication. In conclusion, DEH exerts its inhibitory activity against H1N1 infection by activating the TFEB/autophagy-lysosome pathway.
Influenza A Virus, H1N1 Subtype/genetics* ; Animals ; Autophagy/drug effects* ; Humans ; Mice ; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/genetics* ; Influenza, Human/metabolism* ; Lysosomes/metabolism* ; Orthomyxoviridae Infections/genetics* ; Eugenol/pharmacology* ; Antiviral Agents/pharmacology* ; Virus Replication/drug effects* ; A549 Cells ; Male

Objective To explore the effect of the knockdown of transmembrane 9 superfamily protein member 2 (TM9SF2) on the replication of vesicular stomatitis virus (VSV), and investigate its role in the mechanism of antiviral innate immunity. Methods Small interfering RNA (siRNA) was used to knock down the TM9SF2 gene in human non-small cell lung cancer A549 cells. The CCK-8 method was used to assess cell proliferation. A VSV-green fluorescent protein (VSV-GFP) infected cell model was established. The plaque assay was used to measure the viral titer in the supernatant. RT-qPCR and Western blotting were employed to quantify the mRNA and protein levels of VSV genome replication in A549 cells following VSV infection, as well as the expression of interferon β (IFN-β) mRNA and interferon regulatory factor 3 (IRF3) protein phosphorylation following polyinosinic-polycytidylic acid (poly(I:C)) stimulation. Results Compared to the negative control, the knockdown of TM9SF2 exhibited a significant effect, with no observed impact on A549 cell proliferation. The VSV-GFP infected A549 cell model was successfully established. After viral stimulation, fluorescence intensity was reduced following TM9SF2 knockdown, and the mRNA and protein levels of VSV were significantly downregulated. The viral titer of VSV was decreased. After poly(I:C) stimulation, TM9SF2 knockdown significantly upregulated the mRNA level of IFN-β and the phosphorylation level of IRF3 protein. Conclusion The knockdown of TM9SF2 inhibits the replication of vesicular stomatitis virus, and positively regulates the type I interferon signaling pathway, thus enhancing the host's antiviral innate immune response.
Humans ; Virus Replication/genetics* ; Signal Transduction ; Membrane Proteins/metabolism* ; A549 Cells ; Vesiculovirus/physiology* ; Interferon-beta/metabolism* ; Interferon Regulatory Factor-3/genetics* ; Interferon Type I/metabolism* ; Vesicular Stomatitis/immunology* ; Gene Knockdown Techniques ; Vesicular stomatitis Indiana virus/physiology* ; RNA, Small Interfering/genetics*

The study aims to investigate the impacts of prolyl oligopeptidase (POP) on the replication of foot-and-mouth disease virus (FMDV) in BHK-21 cells. Firstly, the effects of FMDV replication on POP expression in BHK-21 cells were analyzed by Western blotting and Real-time reverse transcription polymerase chain reaction (RT-qPCR). Secondly, a eukaryotic expression plasmid for POP was constructed, and the effects of POP overexpression on the replication of two different serotypes of FMDV were assessed by Western blotting, RT-qPCR, and virus titer assays. Thirdly, specific small interfering RNAs (siRNAs) targeting POP were synthesized, and their efficiency in interfering with endogenous POP expression was identified by RT-qPCR. The impacts of downregulating endogenous POP expression on FMDV replication were further evaluated by Western blotting, RT-qPCR, and virus titer assays. The results indicated that FMDV infection did not significantly affect POP expression in BHK-21 cells. Overexpression of POP dose-dependently enhanced the replication of both FMDV/O and FMDV/A serotypes. Conversely, siRNA-mediated downregulation of endogenous POP expression markedly suppressed FMDV/O replication. This study is the first to demonstrated that the role of the host POP protein in promoting FMDV replication in BHK-21 cells, thereby providing a critical theoretical foundation and potential molecular targets for developing efficient candidate cell strains for foot-and-mouth disease inactivated vaccines.
Foot-and-Mouth Disease Virus/genetics* ; Virus Replication/genetics* ; Prolyl Oligopeptidases ; Serine Endopeptidases/physiology* ; Animals ; Cell Line ; RNA, Small Interfering/genetics* ; Foot-and-Mouth Disease/virology* ; Cricetinae

The small G-protein Rac1 is the main regulatory factor of the actin cytoskeleton. Rac1 cycles between the inactive GDP-bound form and the active GTP-bound form. Rac1 not only promotes viral replication and infection, but also regulates the actin cytoskeleton rearrangement, adhesion, and invasion of glioma cells. In addition, Rac1 is implicated in human diseases such as tumors and epilepsy. This article reviews the latest research on the small G-protein Rac1 in virology, cell biology, and human pathology. It is found that the existence of Rac1 is closely related to the replication and infection of viruses, that is, inhibiting the existence of Rac1 can effectively reduce the replication and transportation of viruses, providing new ideas for the development of various therapeutic drugs targeting Rac1.
Humans ; rac1 GTP-Binding Protein/genetics* ; Virus Replication ; Glioma/pathology* ; Actin Cytoskeleton/metabolism* ; Animals

To screen and identify the key host proteins interacting with the non-structural protein 15 (Nsp15) of porcine epidemic diarrhea virus (PEDV). The IP/pull-down assay and mass spectrometry were employed to screen and identify the host proteins interacting with Nsp15. The interaction between the host protein and Nsp15 was studied by co-immunoprecipitation and laser scanning confocal microscopy. Finally, Western blotting and RT-qPCR were employed to examine the interaction between SLC25a3 and PEDV. The recombinant eukaryotic expression vector pcDNA3.1(+)-Flag-Nsp15 was successfully constructed, and the host protein SLC25a3 interacting with PEDV Nsp15 was screened out. An interaction existed between SLC25a3 and Nsp15, and SLC25a3 significantly inhibited PEDV replication in a dose-dependent manner. SLC25a3 inhibits PEDV replication. The results of this study provide a basis for deciphering the role and mechanism of SLC25a3 in the host immune response to PEDV infection.
Porcine epidemic diarrhea virus/genetics* ; Viral Nonstructural Proteins/metabolism* ; Animals ; Swine ; Virus Replication ; Coronavirus Infections/veterinary* ; Swine Diseases/metabolism*

This work aims to explore the effect of glycolysis on the replication of porcine reproductive and respiratory syndrome virus (PRRSV) in porcine alveolar macrophages (PAMs). The changes of glucose metabolism, PRRSV protein levels, PRRSV titers, and the relative expression levels of genes and proteins in PAMs were analyzed by ELISA, qPCR, virus titration, and Western blotting after PRRSV infection. The effect of hypoxia-inducible factor-1α (HIF-1α) on PRRSV replication was subsequently assessed by specific siRNAs targeting to HIF-1α. The results showed that PRRSV infection enhanced glycolysis, elevated the levels of glucose uptake and lactate in the supernatant (P<0.05 and 0.01, respectively), reduced ATP production (P<0.05), and up-regulated the expression of hexokinase 2 (HK2), 6-phosphofructo-2-kinase/fructose-2, 6-biphosphatase 3 (PFKFB3), and pyruvate kinase isozyme type M2 (PKM2) in PAMs (P<0.05 and 0.01, respectively). Glycolysis inhibitors down-regulated the expression of PRRSV proteins and reduced virus titers (P<0.01). The knockdown of HIF-1α by siRNAs inhibited glycolysis and lowered PRRSV titers (P<0.05). In addition, the interferon pathways inhibited by PRRSV infection were reversed by the inhibition of glycolysis. These findings may facilitate further investigation of the role of glycolysis in PRRSV replication.
Porcine respiratory and reproductive syndrome virus/physiology* ; Glycolysis ; Swine ; Animals ; Virus Replication ; Hypoxia-Inducible Factor 1, alpha Subunit/genetics* ; Macrophages, Alveolar/metabolism* ; Porcine Reproductive and Respiratory Syndrome/virology* ; Cells, Cultured ; RNA, Small Interfering/genetics*

BACKGROUND: Previous studies have examined the bulk transcriptome of peripheral blood immune cells in acquired immunodeficiency syndrome patients experiencing immunological non-responsiveness. This study aimed to investigate the characteristics of specific immune cell subtypes in acquired immunodeficiency syndrome patients who exhibit immunological non-responsiveness. METHODS: A single-cell transcriptome sequencing of peripheral blood mononuclear cells obtained from both immunological responders (IRs) (CD4 + T-cell count >500) and immunological non-responders (INRs) (CD4 + T-cell count <300) was conducted. The transcriptomic profiles were used to identify distinct cell subpopulations, marker genes, and differentially expressed genes aiming to uncover potential genetic factors associated with immunological non-responsiveness. RESULTS: Among the cellular subpopulations analyzed, the ratios of monocytes, CD16 + monocytes, and exhausted B cells demonstrated the most substantial differences between INRs and IRs, with fold changes of 39.79, 11.08, and 2.71, respectively. In contrast, the CD4 + T cell ratio was significantly decreased (0.39-fold change) in INRs compared with that in IRs. Similarly, the ratios of natural killer cells and terminal effector CD8 + T cells were also lower (0.37-fold and 0.27-fold, respectively) in the INRs group. In addition to several well-characterized immune cell-specific markers, we identified a set of 181 marker genes that were enriched in biological pathways associated with human immunodeficiency virus (HIV) replication. Notably, ISG15 , IFITM3 , PLSCR1 , HLA-DQB1 , CCL3L1 , and DDX5 , which have been demonstrated to influence HIV replication through their interaction with viral proteins, emerged as significant monocyte marker genes. Furthermore, the differentially expressed genes in natural killer cells were also enriched in biological pathways associated with HIV replication. CONCLUSIONS We generated an atlas of immune cell transcriptomes in HIV-infected IRs and INRs. Host genes associated with HIV replication were identified as markers of, and were found to be differentially expressed in, different types of immune cells.
Humans ; Acquired Immunodeficiency Syndrome ; Transcriptome/genetics* ; HIV ; HIV Infections/genetics* ; Leukocytes, Mononuclear/metabolism* ; CD4-Positive T-Lymphocytes/metabolism* ; Virus Replication ; Membrane Proteins/metabolism* ; RNA-Binding Proteins/metabolism*

Porcine epidemic diarrhea virus (PEDV) is a highly pathogenic virus that can cause acute intestinal infectious diseases in both piglets and fattening pigs. The virus encodes at least 16 non-structural proteins, including nsp9, which has been shown to bind to single-stranded RNA. However, its function and mechanism remain unclear. In this study, we aimed to identify potential host proteins that interact with PEDV nsp9 using immunoprecipitation combined with mass spectrometry. The interactions were then confirmed by co-immunoprecipitation (Co-IP) and confocal laser scanning fluorescence techniques. The results showed that nsp9 interacts with HSPA8, Tollip, HSPA9 and TOMM70. Among them, overexpression of HSPA8 resulted in caused first upregulated and then down-regulated expression of nsp9, and promoted the proliferation of PEDV. Overexpression of Tollip significantly upregulated the expression of nsp9 and inhibited the proliferation of PEDV. Overexpression of TOMM70 significantly reduced the expression of nsp9, but did not show significant effect on the proliferation of PEDV. Overexpression of HSPA9 did not show significant effect on the expression of nsp9 and the proliferation of PEDV. These findings may facilitate further investigating the role of nsp9-interacting proteins in PEDV infection.
Animals ; Swine ; Porcine epidemic diarrhea virus/genetics* ; Virus Replication ; Proteins ; Swine Diseases

BACKGROUND: The hepatitis B virus (HBV) vaccine has been efficiently used for decades. However, hepatocellular carcinoma caused by HBV is still prevalent globally. We previously reported that interferon (IFN)-induced tripartite motif-containing 25 (TRIM25) inhibited HBV replication by increasing the IFN expression, and this study aimed to further clarify the anti-HBV mechanism of TRIM25. METHODS: The TRIM25-mediated degradation of hepatitis B virus X (HBx) protein was determined by detecting the expression of HBx in TRIM25-overexpressed or knocked-out HepG2 or HepG2-NTCP cells via Western blotting. Co-immunoprecipitation was performed to confirm the interaction between TRIM25 and HBx, and colocalization of TRIM25 and HBx was identified via immunofluorescence; HBV e-antigen and HBV surface antigen were qualified by using an enzyme-linked immunosorbent assay (ELISA) kit from Kehua Biotech. TRIM25 mRNA, pregenomic RNA (pgRNA), and HBV DNA were detected by quantitative real-time polymerase chain reaction. The retinoic acid-inducible gene I (RIG-I) and pgRNA interaction was verified by RNA-binding protein immunoprecipitation assay. RESULTS: We found that TRIM25 promoted HBx degradation, and confirmed that TRIM25 could enhance the K90-site ubiquitination of HBx as well as promote HBx degradation by the proteasome pathway. Interestingly, apart from the Really Interesting New Gene (RING) domain, the SPRY domain of TRIM25 was also indispensable for HBx degradation. In addition, we found that the expression of TRIM25 increased the recognition of HBV pgRNA by interacting with RIG-I, which further increased the IFN production, and SPRY, but not the RING domain is critical in this process. CONCLUSIONS The study found that TRIM25 interacted with HBx and promoted HBx-K90-site ubiquitination, which led to HBx degradation. On the other hand, TRIM25 may function as an adaptor, which enhanced the recognition of pgRNA by RIG-I, thereby further promoting IFN production. Our study can contribute to a better understanding of host-virus interaction.
Humans ; Hepatitis B virus ; DEAD Box Protein 58/metabolism* ; RNA ; Liver Neoplasms ; Virus Replication ; Tripartite Motif Proteins/genetics* ; Transcription Factors ; Ubiquitin-Protein Ligases/genetics*

The resolution of the hepatitis C issue has raised expectations for a chronic hepatitis B cure, driving the industry to expand investment in research and development efforts to strengthen functional cure strategies. These strategies have a wide variety of types, and the published research findings are heterogeneous. The theoretical analysis of these strategies is of great significance for determining prioritized research orientations as well as sensibly allocating research and development resources. However, due to a paucity of necessary conceptual models, current theoretical analysis has not been able to unify various therapeutic strategies into a proper theoretical framework. In view of the fact that the decrease in the quantity of cccDNA is an inevitable core event accompanied by the process of functional cure, this paper intends to analyze several chronic hepatitis B cure strategies using cccDNA dynamics as a framework. Furthermore, there are currently few studies on the dynamics of the cccDNA field, hoping that this article can promote recognition and research in this field.
Humans ; Hepatitis B virus/genetics* ; Hepatitis B, Chronic/drug therapy* ; Antiviral Agents/therapeutic use* ; Virus Replication ; DNA, Circular/therapeutic use* ; DNA, Viral/genetics* ; Hepatitis B/drug therapy*