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*

Virus-induced senescence (VIS) is a significant biological phenomenon, which is associated with declining immune function, accelerating aging process and causing aging-related diseases. A variety of common viruses, including RNA viruses (such as SARS-CoV-2), DNA viruses (such as herpesviruses and hepatitis B virus), and prions can cause VIS in host cells. The primary mechanisms include abnormal activation of the cGAS-STING signaling pathway, DNA damage response, and potential correlations with the integrated stress response due to intracellular phase separation. Viral infection and cellular senescence influence each other: cellular senescence serves as a defense to restrict viral replication and transmission, while some viruses exploit cellular senescence to enhance their infectivity and replication. Understanding the mechanisms of VIS is conducive to the development of therapeutic strategies for viral infections and promotion of healthy aging. However, there is lack of research on therapeutic targets and drug development in this field so far. Although senolytics may be effective for anti-senescent cells therapy, their efficacy for VIS needs evidence from further clinical trials. This article reviews the research progress on the connection between viral infection and cellular senescence, to provide insights for the prevention and treatment of aging related diseases.
Humans ; Cellular Senescence/physiology* ; Virus Diseases/physiopathology* ; Signal Transduction ; Nucleotidyltransferases/metabolism* ; DNA Damage ; Virus Replication ; COVID-19 ; Membrane Proteins/metabolism* ; SARS-CoV-2

Paramyxoviruses are important respiratory pathogens with substantial clinical relevance in pediatric infectious diseases. During infection, multiple forms of programmed cell death (PCD) may be induced, and this plays pivotal roles in viral replication, dissemination, and host immune responses, thereby profoundly influencing the viral life cycle and disease progression. On one hand, PCD facilitates the clearance of infected cells, restricts viral spread, and activates host immune defenses, thereby enhancing antiviral immunity. On the other hand, excessive or dysregulated cell death may lead to tissue damage and immune imbalance, creating a microenvironment conducive to viral replication and exacerbating disease severity. For instance, apoptosis-mediated by both extrinsic and intrinsic pathways-contributes to infection control but may also be hijacked by viruses to promote dissemination. Pyroptosis, driven by inflammasome activation, triggers lytic cell death and the release of pro-inflammatory cytokines. Necroptosis, mediated by the RIPK1-RIPK3-MLKL signaling axis, and pyroptosis both amplify innate immune responses but may concurrently induce inflammatory dysregulation. Immunogenic cell death (ICD), characterized by the release of damage-associated molecular patterns and neoantigens, activates antigen-specific immune responses and holds therapeutic potential for antiviral and antitumor interventions. Emerging evidence suggests that ferroptosis, through the modulation of iron metabolism and associated transporters, may also participate in viral replication and infected cell clearance. This review comprehensively summarizes the roles of apoptosis, pyroptosis, necroptosis, ICD, and ferroptosis in paramyxovirus infection, aiming to deepen the understanding of paramyxovirus pathogenesis and to provide insights for developing novel antiviral strategies.
Humans ; Paramyxoviridae Infections/pathology* ; Pyroptosis ; Apoptosis ; Virus Replication ; Necroptosis ; Inflammasomes ; Immunity, Innate ; Immunogenic Cell Death ; Paramyxoviridae/physiology* ; Signal Transduction

OBJECTIVE: To analyze the Epstein-Barr virus (EBV) load in different lymphocyte subsets, as well as clinical characteristics and outcomes in patients with hematologic malignancies experiencing EBV reactivation. METHODS: Peripheral blood samples from patients were collected. B, T, and NK cells were isolated sorting with magnetic beads by flow cytometry. The EBV load in each subset was quantitated by real-time quantitative polymerase chain reaction (RT-qPCR). Clinical data were colleted from electronic medical records. Survival status was followed up through outpatient visits and telephone calls. Statistical analyses were performed using SPSS 25.0. RESULTS: A total of 39 patients with hematologic malignancies were included, among whom 35 patients had undergone allogeneic hematopoietic stem cell transplantation (allo-HSCT). The median time to EBV reactivation was 4.8 months (range: 1.7-57.1 months) after allo-HSCT. EBV was detected in B, T, and NK cells in 20 patients, in B and T cells in 11 patients, and only in B cells in 4 patients. In the 35 patients, the median EBV load in B cells was 2.19×10⁴ copies/ml, significantly higher than that in T cells (4.00×10³ copies/ml, P <0.01) and NK cells (2.85×10² copies/ml, P <0.01). Rituximab (RTX) was administered for 32 patients, resulting in EBV negativity in 32 patients with a median time of 8 days (range: 2-39 days). Post-treatment analysis of 13 patients showed EBV were all negative in B, T, and NK cells. In the four non-transplant patients, the median time to EBV reactivation was 35 days (range: 1-328 days) after diagnosis of the primary disease. EBV was detected in one or two subsets of B, T, or NK cells, but not simultaneously in all three subsets. These patients received a combination chemotherapy targeting at the primary disease, with 3 patients achieving EBV negativity, and the median time to be negative was 40 days (range: 13-75 days). CONCLUSION In hematologic malignancy patients after allo-HSCT, EBV reactivation commonly involves B, T, and NK cells, with a significantly higher viral load in B cells compared to T and NK cells. Rituximab is effective for EBV clearance. In non-transplant patients, EBV reactivation is restricted to one or two lymphocyte subsets, and clearance is slower, highlighting the need for prompt anti-tumor therapy.
Humans ; Hematologic Neoplasms/virology* ; Herpesvirus 4, Human/physiology* ; Epstein-Barr Virus Infections ; Hematopoietic Stem Cell Transplantation ; Virus Activation ; Lymphocyte Subsets/virology* ; Flow Cytometry ; Killer Cells, Natural/virology* ; Male ; Female ; B-Lymphocytes/virology* ; Viral Load ; Adult ; T-Lymphocytes/virology* ; Middle Aged

OBJECTIVE: This study aimed to investigate the prevalence of HIV pretreatment drug resistance (PDR) and the transmission clusters associated with PDR-related mutations in newly diagnosed, treatment-naive patients between 2020 and 2023 in Dehong prefecture, Yunnan province, China. METHODS: Demographic information and plasma samples were collected from study participants. PDR was assessed using the Stanford HIV Drug Resistance Database. The Tamura-Nei 93 model within HIV-TRACE was employed to compute pairwise matches with a genetic distance of 0.015 substitutions per site. RESULTS: Among 948 treatment-naive individuals with eligible sequences, 36 HIV subtypes were identified, with unique recombinant forms (URFs) being the most prevalent (18.8%, 178/948). The overall prevalence of PDR was 12.4% (118/948), and resistance to non-nucleotide reverse transcriptase inhibitors (NNRTIs), nucleotide reverse transcriptase inhibitors (NRTIs), and protease inhibitors (PIs) was 10.7%, 1.3%, and 1.6%, respectively. A total of 91 clusters were identified, among which eight showed evidence of PDR strain transmission. The largest PDR-associated cluster consisted of six CRF01_AE drug-resistant strains carrying K103N and V179T mutations; five of these individuals had initial CD4+ cell counts < 200 cells/μL. CONCLUSION The distribution of HIV subtypes in Dehong is diverse and complex. PDR was moderately prevalent (12.4%) between 2020 and 2023. Evidence of transmission of CRF01_AE strains carrying K103N and V179T mutations was found. Routine surveillance of PDR and the strengthening of control measures are essential to limit the spread of drug-resistance HIV strains.
Humans ; HIV Infections/virology* ; China/epidemiology* ; Drug Resistance, Viral ; Male ; Adult ; Female ; Middle Aged ; HIV-1/genetics* ; Anti-HIV Agents/therapeutic use* ; Myanmar/epidemiology* ; Young Adult ; Prevalence ; Adolescent ; Mutation

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

Porcine reproductive and respiratory syndrome (PRRS), caused by the porcine reproductive and respiratory syndrome virus (PRRSV), is one of the major diseases threatening the swine industry. This study aims to rationally design and optimize natural antimicrobial peptides to identify antiviral candidates with potent inhibitory activity against PRRSV, thereby establishing a foundation for the development of novel preventive and therapeutic agents targeting PRRS. In this study, with cecropin D (CD) as the parent peptide, three derivatives (CD-2, CD-3, and CD-4) were designed through amino acid substitutions. CD and derived peptides were obtained by solid-phase peptide synthesis. MS and reversed-phase (RP)-HPLC were employed for sequence identification, purification, and purity analysis. The secondary structures of the peptides were investigated by circular dichroism spectroscopy. CellTiter 96^® AQueous one solution cell proliferation assay was used to evaluate the cytotoxicity of the peptides. The inhibitory activities and mechanisms of the peptides against PRRSV were studied by Western blotting, RT-qPCR, and indirect immunofluorescence assay. The MS and RP-HPLC results showed that CD and derived peptides were successfully synthesized, with the purity reaching up to 95%. Circular dichroism analysis revealed that the CD derivatives exhibited more stable and abundant α-helices in a cell membrane-mimicking environment. The MTS assay indicated that all tested peptides at 100 μg/mL had negligible cytotoxicity. The experimental results of the action phase of the peptide against PRRSV demonstrated that the derived peptides significantly enhanced antiviral activities at the viral entry stage compared with the parent peptide. This enhancement was attributed to the introduction of lysine, tryptophan, and phenylalanine, which increased the hydrophobicity and positive charge of the peptides. These findings provide a theoretical basis for the application and structural optimization of antiviral peptides and may offer a new strategy for preventing and controlling PRRSV.
Porcine respiratory and reproductive syndrome virus/physiology* ; Animals ; Swine ; Antiviral Agents/chemistry* ; Porcine Reproductive and Respiratory Syndrome/virology* ; Virus Internalization/drug effects* ; Antimicrobial Peptides/chemistry*

The Ebola virus (EBOV), a member of the Filoviridae family, is a highly pathogenic agent responsible for severe hemorrhagic fever in humans. Understanding the molecular mechanisms governing its replication is critical for developing effective antiviral strategies. VP35-TurboID immunosuppression coupled with quantitative mass spectrometry identified Septin9, the host GTP-binding protein which played a role in cytoskeletal regulation, as a novel interactor of VP35. Western blotting and Far-Western blotting confirmed the direct interaction and demonstrated that the C-terminal region of VP35 was the critical binding domain. Functionally, EBOV replication as well as the formation of viral inclusion bodies (VIBs) was demonstrated to be significantly suppressed by Septin9 knockdown and depletion, as shown by the EBOV minigenome (EBOV MG) and the transcription- and replication-competent virus-like particles (trVLPs) system. This study reveals that VP35 engages in a specific interaction with the GTP-binding protein Septin9, thereby impeding EBOV replication through the disruption of inclusion bodies. The overarching objective of this study is to significantly enhance our understanding about the pathogenic mechanism of EBOV and offer a robust theoretical foundation and solid empirical support for the formulation of innovative therapeutic strategies against EBOV.
Virus Replication/physiology* ; Septins/physiology* ; Humans ; Ebolavirus/physiology* ; Inclusion Bodies, Viral/metabolism* ; Viral Regulatory and Accessory Proteins/metabolism* ; Hemorrhagic Fever, Ebola/virology*

Geminiviruses cause substantial crop yield losses worldwide. The replication initiator protein (Rep) encoded by geminiviruses is indispensable for geminiviral replication. The Rep protein encoded by beet severe curly top virus (BSCTV, genus Curtovirus, family Geminiviridae) induces VARIANT IN METHYLATION 5 (VIM5) expression in Arabidopsis leaves upon BSCTV infection. VIM5 functions as a ubiquitination-related E3 ligase to promote the proteasomal degradation of methyltransferases, resulting in reduction of methylation levels in the BSCTV C2-3 promoter. However, the specific domains of Rep responsible for VIM5 induction remain poorly characterized. Although Rep proteins from several geminiviruses act as viral suppressors of RNA silencing (VSRs), whether BSCTV Rep also possesses VSR activity remains to be illustrated. In this study, we employed a transient expression system in the 16c-GFP transgenic and the wild-type Nicotiana benthamiana plants to analyze the VSR and the VIM5-inducing activities of different truncated Rep proteins haboring distinct domains. We found that the N-terminal domain (amino acids 1-180) of Rep suppressed GFP silencing in 16c-GFP transgenic N. benthamiana leaves. The minimal N-terminal fragment (amino acids 1-104) induced VIM5 expression upon co-infiltration, while C-terminal truncations lacked VIM5-inducing activity. Our results indicate that the N-terminal domain of Rep encoded by BSCTV mediates the suppression of RNA silencing and induces VIM5 expression. Thus, our findings contribute to a better understanding of interactions between geminiviral Rep and plant hosts.
Geminiviridae/genetics* ; Nicotiana/metabolism* ; Arabidopsis/metabolism* ; RNA Interference ; Viral Proteins/metabolism* ; Arabidopsis Proteins/metabolism* ; Plants, Genetically Modified/metabolism* ; Protein Domains ; Plant Diseases/virology* ; Methyltransferases/metabolism* ; Ubiquitin-Protein Ligases/metabolism* ; DNA Helicases/genetics*