SARS-CoV-2 Nsp5 Activates NF-κB Pathway by Upregulating SUMOylation of MAVS.
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ABSTRACT:
SUBMITTER: Li W
PROVIDER: S-EPMC8631293 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leads to NF-κB activation and induction of pro-inflammatory cytokines, though the underlying mechanism for this activation is not fully understood. Our results reveal that the SARS-CoV-2 Nsp14 protein contributes to the viral activation of NF-κB signaling. Nsp14 caused the nuclear translocation of NF-κB p65. Nsp14 induced the upregulation of IL-6 and IL-8, which also occurred in SARS-CoV-2 infected cells. IL-8 upregulation was further confirmed in lung tissue samples from COVID-19 patients. A previous proteomic screen identified the putative interaction of Nsp14 with host Inosine-5'-monophosphate dehydrogenase 2 (IMPDH2) protein, which is known to regulate NF-κB signaling. We confirmed the Nsp14-IMPDH2 protein interaction and found that IMPDH2 knockdown or chemical inhibition using ribavirin (RIB) and mycophenolic acid (MPA) abolishes Nsp14-mediated NF-κB activation and cytokine induction. Furthermore, IMDPH2 inhibitors (RIB, MPA) efficiently blocked SARS-CoV-2 infection, indicating that IMDPH2, and possibly NF-κB signaling, is beneficial to viral replication. Overall, our results identify a novel role of SARS-CoV-2 Nsp14 in causing the activation of NF-κB.
| S-EPMC8168382 | biostudies-literature
Project description:Pathogenesis of COVID-19 is associated with a hyperinflammatory response; however, the precise mechanism of SARS-CoV-2-induced inflammation is poorly understood. Here we investigated direct inflammatory functions of major structural proteins of SARS-CoV-2. We observed that spike (S) protein potently induces inflammatory cytokines and chemokines including IL-6, IL-1ß, TNFa, CXCL1, CXCL2, and CCL2, but not IFNs in human and mouse macrophages. No such inflammatory response was observed in response to membrane (M), envelope (E), and neucleocapsid (N) proteins. When stimulated with extracellular S protein, human lung epithelial cells A549 also produce inflammatory cytokines and chemokines. Interestingly, epithelial cells expressing S protein intracellularly are non-inflammatory, but elicit an inflammatory response in macrophages when co-cultured. Biochemical studies revealed that S protein triggers inflammation via activation of the NF-κB pathway in a MyD88-dependent manner. Further, such an activation of the NF-κB pathway is abrogated in Tlr2-deficient macrophages. Consistently, administration of S protein induces IL-6, TNF-a, and IL-1 ß in wild-type, but not Tlr2-deficient mice. Together these data reveal a mechanism for the cytokine storm during SARS-CoV-2 infection and suggest that TLR2 could be a potential therapeutic target for COVID-19.
| S-EPMC7987013 | biostudies-literature
Project description:The pathogenesis of COVID-19 is associated with a hyperinflammatory response; however, the precise mechanism of SARS-CoV-2-induced inflammation is poorly understood. Here, we investigated direct inflammatory functions of major structural proteins of SARS-CoV-2. We observed that spike (S) protein potently induced inflammatory cytokines and chemokines, including IL-6, IL-1β, TNFα, CXCL1, CXCL2, and CCL2, but not IFNs in human and mouse macrophages. No such inflammatory response was observed in response to membrane (M), envelope (E), and nucleocapsid (N) proteins. When stimulated with extracellular S protein, human and mouse lung epithelial cells also produced inflammatory cytokines and chemokines. Interestingly, epithelial cells expressing S protein intracellularly were non-inflammatory, but elicited an inflammatory response in macrophages when co-cultured. Biochemical studies revealed that S protein triggers inflammation via activation of the NF-κB pathway in a MyD88-dependent manner. Further, such an activation of the NF-κB pathway was abrogated in Tlr2-deficient macrophages. Consistently, administration of S protein-induced IL-6, TNF-α, and IL-1β in wild-type, but not Tlr2-deficient mice. Notably, upon recognition of S protein, TLR2 dimerizes with TLR1 or TLR6 to activate the NF-κB pathway. Taken together, these data reveal a mechanism for the cytokine storm during SARS-CoV-2 infection and suggest that TLR2 could be a potential therapeutic target for COVID-19.
| S-EPMC8709575 | biostudies-literature
Project description:In Drosophila, Toll/NF-κB signaling plays key roles in both animal development and in host defense. The activation, intensity, and kinetics of Toll signaling are regulated by posttranslational modifications such as phosphorylation, SUMOylation, or ubiquitination that target multiple proteins in the Toll/NF-κB cascade. Here, we have generated a CRISPR-Cas9 edited Dorsal (DL) variant that is SUMO conjugation resistant. Intriguingly, embryos laid by dlSCR mothers overcome dl haploinsufficiency and complete the developmental program. This ability appears to be a result of higher transcriptional activation by DLSCR. In contrast, SUMOylation dampens DL transcriptional activation, ultimately conferring robustness to the dorso-ventral program. In the larval immune response, dlSCR animals show an increase in crystal cell numbers, stronger activation of humoral defense genes, and high cactus levels. A mathematical model that evaluates the contribution of the small fraction of SUMOylated DL (1-5%) suggests that it acts to block transcriptional activation, which is driven primarily by DL that is not SUMO conjugated. Our findings define SUMO conjugation as an important regulator of the Toll signaling cascade, in both development and host defense. Our results broadly suggest that SUMO attenuates DL at the level of transcriptional activation. Furthermore, we hypothesize that SUMO conjugation of DL may be part of a Ubc9-dependent mechanism that restrains Toll/NF-κB signaling.
| S-EPMC9252280 | biostudies-literature
Project description:BackgroundOsteoarthritis (OA), a disease with whole-joint damage and dysfunction, is the leading cause of disability worldwide. The progressive loss of hyaline cartilage extracellular matrix (ECM) is considered as its hallmark, but its exact pathogenesis needs to be further clarified. MicroRNA(miRNA) contributes to OA pathology and may help to identify novel biomarkers and therapies against OA. Here we identified miR-214-3p as an important regulator of OA.MethodsqRT-PCR and in situ hybridization were used to detect the expression level of miR-214-3p. The function of miR-214-3p in OA, as well as the interaction between miR-214-3p and its downstream mRNA target (IKBKB), was evaluated by western blotting, immunofluorescence, qRT-PCR and luciferase assay. Mice models were introduced to examine the function and mechanism of miR-214-3p in OA in vivo.FindingsIn our study, we found that miR-214-3p, while being down-regulated in inflamed chondrocytes and OA cartilage, regulated ECM metabolism and cell apoptosis in the cartilage. Mechanically, the protective effect of miR-214-3p downregulated the IKK-β expression and led to the dysfunction of NF-κB signaling pathway. Furthermore, intra-articular injection of miR-214-3p antagomir in mice joints triggered spontaneous cartilage loss while miRNA-214-3p agomir alleviated OA in the experimental mouse models.InterpretationDecreased miR-214-3p activates the NF-κB signaling pathway and aggravates OA development through targeting IKKβ, suggesting miR-214-3p may be a novel therapeutic target for OA.FundingThis study was financially supported by grants from the National Natural Science Foundation of China (81,773,532, 81,974,342).
| S-EPMC7957119 | biostudies-literature
Project description:Shigella dysenteriae (S.dysenteriae) the causative agent of bacillary dysentery invades the human colonic epithelium resulting in severe intestinal inflammatory response and epithelial destruction. However, the mechanism by which S.dysenteriae infection regulates proinflammatory cytokines during intestinal inflammation is still obscure. In this study, we evaluated whether the interaction of β-catenin and NF-κB regulates proinflammatory cytokines TNF-α and IL-8 by modulating GSK-3β activity during S.dysenteriae infection in rat ileal loop model. Here we demonstrated that S.dysenteriae infection stimulate β-catenin degradation which in turn decreased the association between NF-κB and β-catenin. Also, we showed that S.dysenteriae infection increased GSK-3β kinase activity which in turn phosphorylates β-catenin for its degradation by ubiquitination and upregulates IL-8 through NF-κB activation thereby leading to inflammation. Thus these findings revealed the role of β-catenin/ NF-κB and GSK-3β in modulating the inflammatory response during bacterial infection and also showed that β-catenin acts as a critical regulator of inflammation.
| S-EPMC5400225 | biostudies-literature
Project description:BackgroundConstitutively activated nuclear factor kappa B (NF-κB) signalling plays vital roles in bladder urothelial carcinoma (BC) progression. We investigate the effect of receptor-interacting protein kinase 4 (RIPK4) on NF-κB activation and BC progression.MethodsThe expression of RIPK4 was examined in 25 cryopreserved paired bladder samples and 112 paraffin BC specimens. In vivo and in vitro assays were performed to validate effect of RIPK4 on NF-κB pathway-mediated BC progression.ResultsHigh expression of RIPK4 was observed in BC tissues and was an independent predictor for poor overall survival. Up or downregulating the expression of RIPK4 enhanced or inhibited, respectively, the migration and invasion of BC cells in vitro and in vivo. Mechanistically, RIPK4 promoted K63-linked polyubiquitination of tumour necrosis factor receptor-associated factor 2 (TRAF2), receptor-interacting protein (RIP) and NF-κB essential modulator (NEMO). RIPK4 also promoted nuclear localisation of NF-κB-p65, and maintained activation of NF-κB substantially, leading to upregulation of VEGF-A, ultimately promoting BC cell aggressiveness.ConclusionsOur data highlighted the molecular aetiology and clinical significance of RIPK4 in BC: upregulation of RIPK4 contributes to NF-κB activation, and upregulates VEGF-A, and BC progression. Targeting RIPK4 might represent a new therapeutic strategy to improve survival for patients with BC.
| S-EPMC6008479 | biostudies-literature
Project description:SARS-CoV-2, the etiological agent of COVID-19, is characterized by a delay in type I interferon (IFN-I)-mediated antiviral defenses alongside robust cytokine production. Here, we investigate the underlying molecular basis for this imbalance and implicate virus-mediated activation of NF-κB in the absence of other canonical IFN-I-related transcription factors. Epigenetic and single-cell transcriptomic analyses show a selective NF-κB signature that was most prominent in infected cells. Disruption of NF-κB signaling through the silencing of the NF-κB transcription factor p65 or p50 resulted in loss of virus replication that was rescued upon reconstitution. These findings could be further corroborated with the use of NF-κB inhibitors, which reduced SARS-CoV-2 replication in vitro. These data suggest that the robust cytokine production in response to SARS-CoV-2, despite a diminished IFN-I response, is the product of a dependency on NF-κB for viral replication. IMPORTANCE The COVID-19 pandemic has caused significant mortality and morbidity around the world. Although effective vaccines have been developed, large parts of the world remain unvaccinated while new SARS-CoV-2 variants keep emerging. Furthermore, despite extensive efforts and large-scale drug screenings, no fully effective antiviral treatment options have been discovered yet. Therefore, it is of the utmost importance to gain a better understanding of essential factors driving SARS-CoV-2 replication to be able to develop novel approaches to target SARS-CoV-2 biology.
| S-EPMC8577386 | biostudies-literature
Project description:SARS-CoV-2, the etiological agent of COVID-19, is characterized by a delay in Type I interferon (IFN-I)-mediated antiviral defenses alongside robust cytokine production. Here we investigate the underlying molecular basis for this imbalance and implicate virus-mediated activation of NF-κB in the absence of other canonical IFN-I-related transcription factors. Epigenetic and single cell transcriptomic analyses show a selective NF-κB signature that was most prominent in infected cells. Disruption of NF-κB signaling through the silencing of the NF-κB transcription factors p65 or p50 resulted in loss of virus replication that was rescued upon reconstitution. These findings could be further corroborated with the use of NF-κB inhibitors, which reduced SARS-CoV-2 replication in vitro. These data suggest that the robust cytokine production in response to SARS-CoV-2, despite a diminished IFN-I response, is the product of a dependency on NF-κB for viral replication.
2021-09-28 | GSE184536 | GEO
Project description:BACKGROUND:Porcine parvovirus (PPV) is a single-stranded DNA virus that causes porcine reproductive failure. It is of critical importance to study PPV pathogenesis for the prevention and control of the disease. NS1, a PPV non-structural protein, is participated in viral DNA replication, transcriptional regulation, and cytotoxicity. Our previous research showed that PPV can activate nuclear factor kappa B (NF-κB) signaling pathway and then up-regulate the expression of interleukin (IL)-6. OBJECTIVES:Herein, the purpose of this study is to determine whether the non-structural protein NS1 of PPV also has the same function. METHODS:Real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR), enzyme-linked immunosorbent assay, western blot, immunofluorescence assay and small interfering RNA (siRNA) were used. RESULTS:Our findings demonstrated that PPV NS1 protein can up-regulate the expression levels of IL-6 and tumor necrosis factor-alpha in a dose-dependent manner. Moreover, PPV NS1 protein was found to induce the phosphorylation of IκBα, then leading to the phosphorylation and nuclear translocation of NF-κB. In addition, the NS1 protein activated the upstream pathways of NF-κB. Meanwhile, TLR2-siRNA assay showed TLR2 plays an important role in the activation of NF-κB signaling pathway induced by PPV-NS1. CONCLUSIONS:These findings indicated that PPV NS1 protein induced the up-regulated of IL-6 expression through activating the TLR2 and NF-κB signaling pathways. In conclusion, these findings provide a new avenue to study the innate immune mechanism of PPV infection.
| S-EPMC7263913 | biostudies-literature