scholarly journals SARS-CoV-2 Nsp14 activates NF-κB signaling and induces IL-8 upregulation

2021 ◽  
Author(s):  
Tai-Wei Li ◽  
Adam D. Kenney ◽  
Helu Liu ◽  
Guillaume N. Fiches ◽  
Dawei Zhou ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Nuclear Translocation ◽  
Underlying Mechanism ◽  
Tissue Samples ◽  
Proteomic Screen ◽  
Cytokine Induction ◽  
Infected Cells ◽  
Chemical Inhibition ◽  
Pro Inflammatory Cytokines

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.

scholarly journals Down Regulation Of IL-1β Secretion By Tgf-β1 In Macrophages Infected With Dengue Virus

2021 ◽  
Author(s):  
Brenda Ramírez-Aguero ◽  
Javier Serrato-Salas ◽  
José Luis Montiel-Hernández ◽  
Judith González-Christen
Keyword(s):  
Immune Response ◽  
Dengue Virus ◽  
Inflammatory Cytokines ◽  
Denv Infection ◽  
Inhibitory Effect ◽  
Microvascular Endothelium ◽  
Infected Cells ◽  
Tgf Β1 ◽  
Pro Inflammatory Cytokines

AbstractSeveral pathogenic mechanisms have been linked to the severity of dengue virus infection, like viral cytotoxicity, underlying host genetics and comorbidities such as diabetes and dyslipidemia. It has been observed that patients with severe manifestations develop an uncontrolled immune response, with an increase in pro-inflammatory cytokines such as TNF, IL-1β, IL-8, IL-6 and chemokines that damage the human microvascular endothelium, and also in anti-inflammatory cytokines IL-4, IL-10 and TGF-β1. The role of TGF-β1 on dengue is not clear; few studies have been published, and most of them from patient sera data, with both protective and pathological roles have described. The aim of this study was to evaluate the ability of TGF-β1 to regulate the secretion of IL-1β in macrophages infected by DENV using THP-1 cells treated with recombinant TGF-β1 before or after DENV infection. By RT-PCR we did not observe a difference in IL-1β expression between infected cells pretreated with TGF-β1 and those that were not. However, secretion of IL-1β was reduced only in cells stimulated with TGF-β1 before infection, and not in those treated 2 hours post-infection. TGF-β1 receptor blockage with SB505124 inhibitor, prior to the addition of TGF-β1 and infection, abrogated the inhibitory effect of TGF-β1. Our results suggest that DENV could regulate the function of TGF-β1 on macrophages. This negative regulation of the TGF-β1 pathway could be used by DENV to evade the immune response and could contribute to the immunopathology.

scholarly journals 4R Tau Modulates Cocaine-Associated Memory Through Adult Hippocampal Neurogenesis

2020 ◽  
Author(s):  
Hongchun Li ◽  
Wei Xu ◽  
Denian Wang ◽  
Qiyao Fang ◽  
Liang Wang ◽  
...  
Keyword(s):  
Nuclear Translocation ◽  
Underlying Mechanism ◽  
Memory Formation ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Self Administration ◽  
New Strategy ◽  
Contextual Stimuli ◽  
Phosphoinositide 3 Kinase

Abstract Background: Drug memory that generally develops with drug-paired contextual stimuli and drug administration is critical for the development, persistence and relapse of drug addiction. Previous studies have suggested that adult hippocampal neurogenesis (AHN) plays a role in cocaine memory formation; however, the underlying mechanism is not fully understood.Methods: Conditioned place preference (CPP), self-administration and locomotor activity were used to investigate the role of Tau in cocaine-associated memory formation. Virus-mediated gene transfer, western blot, immunohistochemistry, flow cytometry analysis, Tau-interacting proteomics, co-immunoprecipitation, and mutation of 4R Tau were performed. Results: Hippocampal expression of Tau was significantly decreased during the cocaine-associated memory formation. Genetic overexpression of four microtubule-binding repeats Tau (4R Tau) in the hippocampus disrupted cocaine memory by suppressing AHN. Furthermore, 4R Tau directly interacted with phosphoinositide 3-kinase (PI3K)-p85 and impaired its nuclear translocation and PI3K-AKT signaling, processes required for hippocampal neuron proliferation. Conclusions: 4R Tau modulates cocaine memory formation by disrupting AHN, suggesting a novel mechanism underlying cocaine memory formation and provide a new strategy for the treatment of cocaine addiction.

scholarly journals The Role of Mcl-1 inS. aureus-Induced Cytoprotection of Infected Macrophages

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Joanna Koziel ◽  
Katarzyna Kmiecik ◽  
Daniela Chmiest ◽  
Katarzyna Maresz ◽  
Danuta Mizgalska ◽  
...  
Keyword(s):  
De Novo ◽  
Myeloid Cell ◽  
Underlying Mechanism ◽  
Host Cells ◽  
Intracellular Pathogen ◽  
Dependent Inhibition ◽  
Infected Cells ◽  
The Stability

As a facultative intracellular pathogen,Staphylococcus aureusinvades macrophages and then promotes the cytoprotection of infected cells thus stabilizing safe niche for silent persistence. This process occurs through the upregulation of crucial antiapoptotic genes, in particular,myeloid cell leukemia-1 (MCL-1). Here, we investigated the underlying mechanism and signal transduction pathways leading to increasedMCL-1expression in infected macrophages. LiveS. aureusnot only stimulatedde novosynthesis of Mcl-1, but also prolonged the stability of this antiapoptotic protein. Consistent with this, we proved a crucial role of Mcl-1 inS. aureus-induced cytoprotection, since silencing ofMCL1by siRNA profoundly reversed the cytoprotection of infected cells leading to apoptosis. IncreasedMCL1expression in infected cells was associated with enhanced NFκB activation and subsequent IL-6 secretion, since the inhibition of both NFκB and IL-6 signalling pathways abrogated Mcl-1 induction and cytoprotection. Finally, we confirmed our observationin vivoin murine model of septic arthritis showing the association between the severity of arthritis and Mcl-1 expression. Therefore, we propose thatS. aureusis hijacking the Mcl-1-dependent inhibition of apoptosis to prevent the elimination of infected host cells, thus allowing the intracellular persistence of the pathogen, its dissemination by infected macrophages, and the progression of staphylococci diseases.

scholarly journals Niacin Ameliorates Neuro-Inflammation in Parkinson’s Disease via GPR109A

2019 ◽  
Vol 20 (18) ◽  
pp. 4559 ◽  
Author(s):  
Banabihari Giri ◽  
Kasey Belanger ◽  
Marissa Seamon ◽  
Eric Bradley ◽  
Sharad Purohit ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Molecular Mechanism ◽  
Inflammatory Cytokines ◽  
Nuclear Translocation ◽  
Raw264.7 Cells ◽  
Anti Inflammatory ◽  
Neuro Inflammation ◽  
Precise Molecular Mechanism ◽  
Pro Inflammatory Cytokines

In this study, we used macrophage RAW264.7 cells to elucidate the molecular mechanism underlying the anti-inflammatory actions of niacin. Anti-inflammatory actions of niacin and a possible role of its receptor GPR109A have been studied previously. However, the precise molecular mechanism of niacin’s action in reducing inflammation through GPR109A is unknown. Here we observed that niacin reduced the translocation of phosphorylated nuclear kappa B (p-NF-κB) induced by lipopolysaccharide (LPS) in the nucleus of RAW264.7 cells. The reduction in the nuclear translocation in turn decreased the expression of pro-inflammatory cytokines IL-1β, IL-6 in RAW264.7 cells. We observed a decrease in the nuclear translocation of p-NF-κB and the expression of inflammatory cytokines after knockdown of GPR109A in RAW264.7 cells. Our results suggest that these molecular actions of niacin are mediated via its receptor GPR109A (also known as HCAR2) by controlling the translocation of p-NF-κB to the nucleus. Overall, our findings suggest that niacin treatment may have potential in reducing inflammation by targeting GPR109A.

scholarly journals Essential Role of Interferon Regulatory Factor 3 in Direct Activation of RANTES Chemokine Transcription

1999 ◽  
Vol 19 (2) ◽  
pp. 959-966 ◽  
Author(s):  
Rongtuan Lin ◽  
Christophe Heylbroeck ◽  
Pierre Genin ◽  
Paula M. Pitha ◽  
John Hiscott
Keyword(s):  
Virus Infection ◽  
Gene Transcription ◽  
Target Genes ◽  
Nuclear Translocation ◽  
Dominant Negative ◽  
Transactivation Potential ◽  
Infected Cells ◽  
Systemic Cytokine Production ◽  
Rantes Promoter

ABSTRACT Localized and systemic cytokine production in virus-infected cells play an important role in the outcome of viral infection and pathogenicity. Activation of the interferon regulatory factors (IRF) in turn is a critical mediator of cytokine gene transcription. Recent studies have focused on the 55-kDa IRF-3 gene product as a direct transcriptional regulator of type 1 interferon (IFN-α and IFN-β) activation in response to virus infection. Virus infection induces phosphorylation of IRF-3 on specific C-terminal serine residues and permits cytoplasmic-to-nuclear translocation of IRF-3, activation of DNA binding and transactivation potential, and association with the CBP/p300 coactivator. We previously generated constitutively active [IRF-3(5D)] and dominant-negative forms of IRF-3 that control IFN-β and IFN-α gene expression. In an effort to characterize the range of immunoregulatory genes controlled by IRF-3, we now demonstrate that endogenous human RANTES gene transcription is directly induced in tetracycline-inducible IRF-3(5D)-expressing cells or paramyxovirus-infected cells. We also show that a dominant-negative IRF-3 mutant inhibits virus-induced expression of the RANTES promoter. Specific mutagenesis of overlapping ISRE-like sites located between nucleotides −123 and −96 in the RANTES promoter reduces virus-induced and IRF-3-dependent activation. These studies broaden the range of IRF-3 immunoregulatory target genes to include at least one member of the chemokine superfamily.

scholarly journals Role for Nonstructural Protein 1 of Severe Acute Respiratory Syndrome Coronavirus in Chemokine Dysregulation

2006 ◽  
Vol 81 (1) ◽  
pp. 416-422 ◽  
Author(s):  
Anna H. Y. Law ◽  
Davy C. W. Lee ◽  
Benny K. W. Cheung ◽  
Howard C. H. Yim ◽  
Allan S. Y. Lau
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Nonstructural Protein ◽  
Lung Epithelial Cells ◽  
Sars Coronavirus ◽  
Cytokine Induction ◽  
Nonstructural Protein 1 ◽  
Lung Epithelial ◽  
Novel Coronavirus ◽  
Factor Interactions

ABSTRACT Severe acute respiratory syndrome (SARS) is an emerging infectious disease caused by a novel coronavirus. Since its associated morbidity and mortality have been postulated to be due to immune dysregulation, we investigated which of the viral proteins is responsible for chemokine overexpression. To delineate the viral and cellular factor interactions, the role of four SARS coronavirus proteins, including nonstructural protein 1 (nsp-1), nsp-5, envelope, and membrane, were examined in terms of cytokine induction. Our results showed that the SARS coronavirus nsp-1 plays an important role in CCL5, CXCL10, and CCL3 expression in human lung epithelial cells via the activation of NF-κB.

scholarly journals Severe Acute Respiratory Syndrome Coronavirus 2 and the Use of Biologics in Patients With Psoriasis

2020 ◽  
Vol 24 (6) ◽  
pp. 625-632 ◽  
Author(s):  
Matthew Ladda ◽  
Charles Lynde ◽  
Patrick Fleming
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Inflammatory Cytokines ◽  
Biologic Therapy ◽  
Elevated Serum ◽  
Biologic Agents ◽  
World Health ◽  
Individual Risk ◽  
The Impact ◽  
Pro Inflammatory Cytokines

Coronavirus disease (COVID-19), a respiratory disease caused by a novel coronavirus designated severe acute respiratory syndrome coronavirus 2, has rapidly spread worldwide and has been recognized as a pandemic by the World Health Organization. Patients with altered immunologic function are at higher risk of acquiring COVID-19. In patients with psoriasis, inhibition of select pro-inflammatory cytokines through the use of biologic agents has been shown to be an effective treatment option. Pro-inflammatory cytokines have key immunomodulatory effects and are known to be involved in the hosts’ immune response to a variety of viral infections. Though little is currently known about the role of inflammatory cytokines in COVID-19, early reports have shown patients with severe disease to have elevated serum levels of select inflammatory cytokines such as tumor necrosis factor alpha. This review will summarize key information that is currently known about COVID-19, the role of select cytokines in viral defense, and important considerations for patients with psoriasis using biologic agents during this pandemic. Currently, there is insufficient evidence to discontinue biologic therapy in patients with psoriasis who have not tested positive for COVID-19. The decision to pause biologic therapy should be considered on a case-by-case basis in patients in higher risk populations, and should take into account individual risk and benefit. Until more is known about the impact of biologic therapy on COVID-19 outcomes, we recommend patients with psoriasis who test positive for COVID-19 be instructed to discontinue or postpone biologic treatment until they have recovered from infection.

scholarly journals SARS-CoV-2 Nsp5 Activates NF-κB Pathway by Upregulating SUMOylation of MAVS

2021 ◽  
Vol 12 ◽  
Author(s):  
Weiling Li ◽  
Jialu Qiao ◽  
Qiang You ◽  
Shan Zong ◽  
Qian Peng ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Cytokine Production ◽  
Rapid Development ◽  
Signal Pathway ◽  
High Level Expression ◽  
Cytokine Induction ◽  
Tnf Α ◽  
High Level ◽  
Pro Inflammatory Cytokines

The COVID-19 is an infectious disease caused by SARS-CoV-2 infection. A large number of clinical studies found high-level expression of pro-inflammatory cytokines in patients infected with SARS-CoV-2, which fuels the rapid development of the disease. However, the specific molecular mechanism is still unclear. In this study, we found that SARS-CoV-2 Nsp5 can induce the expression of cytokines IL-1β, IL-6, TNF-α, and IL-2 in Calu-3 and THP1 cells. Further research found that Nsp5 enhances cytokine expression through activating the NF-κB signaling pathway. Subsequently, we investigated the upstream effectors of the NF-κB signal pathway on Nsp5 overexpression and discovered that Nsp5 increases the protein level of MAVS. Moreover, Nsp5 can promote the SUMOylation of MAVS to increase its stability and lead to increasing levels of MAVS protein, finally triggering activation of NF-κB signaling. The knockdown of MAVS and the inhibitor of SUMOylation treatment can attenuate Nsp5-mediated NF-κB activation and cytokine induction. We identified a novel role of SARS-CoV-2 Nsp5 to enhance cytokine production by activating the NF-κB signaling pathway.

scholarly journals HIF-1α promotes SARS-CoV-2 infection and aggravates inflammatory responses to COVID-19

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Mingfu Tian ◽  
Weiyong Liu ◽  
Xiang Li ◽  
Peiyi Zhao ◽  
Muhammad Adnan Shereen ◽  
...  
Keyword(s):  
Immune Response ◽  
Virus Infection ◽  
Severe Acute Respiratory Syndrome ◽  
Inflammatory Responses ◽  
Hypoxia Inducible Factor ◽  
Pathological Feature ◽  
Ros Production ◽  
Cytokine Storm ◽  
Infected Cells ◽  
Pro Inflammatory Cytokines

AbstractCytokine storm induced by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a major pathological feature of Coronavirus Disease 2019 (COVID-19) and a crucial determinant in COVID-19 prognosis. Understanding the mechanism underlying the SARS-CoV-2-induced cytokine storm is critical for COVID-19 control. Here, we identify that SARS-CoV-2 ORF3a and host hypoxia-inducible factor-1α (HIF-1α) play key roles in the virus infection and pro-inflammatory responses. RNA sequencing shows that HIF-1α signaling, immune response, and metabolism pathways are dysregulated in COVID-19 patients. Clinical analyses indicate that HIF-1α production, inflammatory responses, and high mortalities occurr in elderly patients. HIF-1α and pro-inflammatory cytokines are elicited in patients and infected cells. Interestingly, SARS-CoV-2 ORF3a induces mitochondrial damage and Mito-ROS production to promote HIF-1α expression, which subsequently facilitates SARS-CoV-2 infection and cytokines production. Notably, HIF-1α also broadly promotes the infection of other viruses. Collectively, during SARS-CoV-2 infection, ORF3a induces HIF-1α, which in turn aggravates viral infection and inflammatory responses. Therefore, HIF-1α plays an important role in promoting SARS-CoV-2 infection and inducing pro-inflammatory responses to COVID-19.

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