scholarly journals Dok-1 and Dok-2 are negative regulators of lipopolysaccharide-induced signaling

2005 ◽  
Vol 201 (3) ◽  
pp. 333-339 ◽  
Author(s):  
Hisaaki Shinohara ◽  
Akane Inoue ◽  
Noriko Toyama-Sorimachi ◽  
Yoshinori Nagai ◽  
Tomoharu Yasuda ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Tyrosine Phosphorylation ◽  
Map Kinases ◽  
Adaptor Proteins ◽  
Mutant Mice ◽  
Poly I:C ◽  
Negative Regulators ◽  
Erk Activation ◽  
Cpg Oligodeoxynucleotides ◽  
Tnf Α

Endotoxin, a bacterial lipopolysaccharide (LPS), causes fatal septic shock via Toll-like receptor (TLR)4 on effector cells of innate immunity like macrophages, where it activates nuclear factor κB (NF-κB) and mitogen-activated protein (MAP) kinases to induce proinflammatory cytokines such as tumor necrosis factor (TNF)-α. Dok-1 and Dok-2 are adaptor proteins that negatively regulate Ras–Erk signaling downstream of protein tyrosine kinases (PTKs). Here, we demonstrate that LPS rapidly induced the tyrosine phosphorylation and adaptor function of these proteins. The stimulation with LPS of macrophages from mice lacking Dok-1 or Dok-2 induced elevated Erk activation, but not the other MAP kinases or NF-κB, resulting in hyperproduction of TNF-α and nitric oxide. Furthermore, the mutant mice showed hyperproduction of TNF-α and hypersensitivity to LPS. However, macrophages from these mutant mice reacted normally to other pathogenic molecules, CpG oligodeoxynucleotides, poly(I:C) ribonucleotides, or Pam3CSK4 lipopeptide, which activated cognate TLRs but induced no tyrosine phosphorylation of Dok-1 or Dok-2. Forced expression of either adaptor, but not a mutant having a Tyr/Phe substitution, in macrophages inhibited LPS-induced Erk activation and TNF-α production. Thus, Dok-1 and Dok-2 are essential negative regulators downstream of TLR4, implying a novel PTK-dependent pathway in innate immunity.

scholarly journals Characterization of UDP-Activated Purinergic Receptor P2Y6 Involved in Japanese Flounder Paralichthys olivaceus Innate Immunity

2018 ◽  
Vol 19 (7) ◽  
pp. 2095 ◽  
Author(s):  
Shuo Li ◽  
Jiafang Li ◽  
Nan Wang ◽  
Gaixiang Hao ◽  
Jinsheng Sun
Keyword(s):  
Gene Expression ◽  
Innate Immunity ◽  
Purinergic Receptor ◽  
Paralichthys Olivaceus ◽  
Japanese Flounder ◽  
Poly I:C ◽  
Pcr Analysis ◽  
Lps Challenge ◽  
Tnf Α ◽  
P2y6 Receptor

Uridine 5’-diphosphate (UDP)-activated purinergic receptor P2Y6 is a member of a G-protein-coupled purinergic receptor family that plays an important role in mammalian innate immunity. However, the role of the P2Y6 receptor (P2Y6R) in fish immunity has not been investigated. In this report, we characterized a P2Y6R gene from Japanese flounder (Paralichthys olivaceus) and examined its role in fish innate immunity. Sequence analysis reveals that the Japanese flounder P2Y6R protein is conserved and possesses four potential glycosylation sites. Quantitative real-time RT-PCR analysis shows that P2Y6R is broadly distributed in all examined Japanese flounder tissues with dominant expression in the liver. In addition, P2Y6R gene expression was up-regulated in head kidney macrophages (HKMs) upon lipopolysaccharides (LPS) and poly(I:C) stimulations but down-regulated by LPS challenge in peripheral blood leukocytes (PBLs). Furthermore, pharmacological inhibition of the endogenous P2Y6 receptor activity by the potently selective P2Y6R antagonist, MRS 2578, greatly up-regulated pro-inflammatory cytokine interleukin (IL)-1β, IL-6 and TNF-α gene expression in PBL cells treated with UDP. Moreover, LPS- and poly(I:C)-induced gene expression of IL-1β and TNF-α in Japanese flounder PBL cells was attenuated significantly by inhibition of P2Y6R activity with antagonist MRS 2578. Collectively, we, for the first time, showed the involvement of functional purinergic P2Y6R in fish innate immunity.

scholarly journals Differential Regulation of Proinflammatory Cytokine Expression by Mitogen-Activated Protein Kinases in Macrophages in Response to Intestinal Parasite Infection

2014 ◽  
Vol 82 (11) ◽  
pp. 4789-4801 ◽  
Author(s):  
Mei Xing Lim ◽  
Chin Wen Png ◽  
Crispina Yan Bing Tay ◽  
Joshua Ding Wei Teo ◽  
Huipeng Jiao ◽  
...  
Keyword(s):  
Protein Expression ◽  
Proinflammatory Cytokines ◽  
Proinflammatory Cytokine ◽  
Map Kinases ◽  
Cytokine Expression ◽  
Content Type ◽  
Erk Activation ◽  
Proinflammatory Cytokine Expression ◽  
Tnf Α ◽  
Mitogen Activated Protein

ABSTRACTBlastocystisis a common enteric protistan parasite that can cause acute, as well as chronic, infection and is associated with irritable bowel syndrome (IBS). However, the pathogenic status ofBlastocystisinfection remains unclear. In this study, we found thatBlastocystisantigens induced abundant expression of proinflammatory cytokines, including interleukin 1β (IL-1β), IL-6, and tumor necrosis factor alpha (TNF-α), in mouse intestinal explants, in mouse colitis colon, and in macrophages. Further investigation utilizing RAW264.7 murine macrophages showed thatBlastocystistreatment in RAW264.7 macrophages induced the activation of ERK, JNK, and p38, the three major groups of mammalian mitogen-activated protein (MAP) kinases that play essential roles in the expression of proinflammatory cytokines. ERK inhibition in macrophages significantly suppressed both mRNA and protein expression of IL-6 and TNF-α and mRNA expression of IL-1β. On the other hand, JNK inhibition resulted in reductions in both c-Jun and ERK activation and significant suppression of all three proinflammatory cytokines at both the mRNA and protein levels. Inhibition of p38 suppressed only IL-6 protein expression with no effect on the expression of IL-1β and TNF-α. Furthermore, we found that serine proteases produced byBlastocystisplay an important role in the induction of ERK activation and proinflammatory cytokine expression by macrophages. Our study thus demonstrated for the first time thatBlastocystiscould induce the expression of various proinflammatory cytokines via the activation of MAP kinases and that infection withBlastocystismay contribute to the pathogenesis of inflammatory intestinal diseases through the activation of inflammatory pathways in host immune cells, such as macrophages.

ERK signaling mediates the induction of inflammatory cytokines by bufalin in human monocytic cells

2000 ◽  
Vol 278 (3) ◽  
pp. C500-C508 ◽  
Author(s):  
Masahiro Kurosawa ◽  
Satoshi Numazawa ◽  
Yoshihiro Tani ◽  
Takemi Yoshida
Keyword(s):  
Map Kinase ◽  
Inflammatory Cytokines ◽  
Map Kinases ◽  
Human Leukemia ◽  
Gene Expressions ◽  
Monocytic Cells ◽  
Erk Activation ◽  
Tnf Α ◽  
Kinase Cascade ◽  
Erk Kinase

Treatment of human leukemia THP-1 cells with bufalin, a specific inhibitor of Na+-K+-ATPase, sequentially induces c- fos and inflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) gene expressions before the appearance of mature phenotypes of monocytic cells. In this study we examined the signal transduction leading to bufalin-induced gene expressions. Bufalin selectively activated extracellular signal-regulated kinase (ERK), compared with other mitogen-activated protein (MAP) kinase family members. Pretreatment of THP-1 cells with PD-98059, an inhibitor of the ERK-kinase cascade, abolished bufalin-induced c- fos and IL-1β gene expressions, indicating that the ERK-kinase cascade mediates the induction of inflammatory cytokines by bufalin. Inhibition of the Na+/Ca2+ exchanger by KB-R7943 and of protein kinase C (PKC) by Ro-31-8220 suppressed ERK activation and gene expressions of c- fos and IL-1β. These findings suggest that Na+-K+-ATPase inhibition by bufalin induces calcium influx and thereby activates PKC and ERK. In cells treated with an inhibitor of p38 MAP kinases, SB-203580, bufalin-mediated ERK activation became persistent and the induction of IL-1β and TNF-α expressions was significantly augmented. These results suggest that cross talk in bufalin-mediated ERK activation is negatively regulated by endogenous p38 MAP kinase activations.

Assessment of Key Elements in the Innate Immunity System Among Patients with HIV, HCV, and Coinfections of HIV/HCV

2020 ◽  
Vol 18 (3) ◽  
pp. 194-200
Author(s):  
Maryam Moradi ◽  
Alireza Tabibzadeh ◽  
Davod Javanmard ◽  
Saied Ghorbani ◽  
Farah Bokharaei-Salim ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Mononuclear Cells ◽  
Hiv Infections ◽  
Control Group ◽  
Peripheral Blood Mononuclear ◽  
Hiv Coinfection ◽  
Tnf Α ◽  
Immunity Genes ◽  
Healthy Control ◽  
Hcv Coinfection

Background: Coinfection of Hepatitis C virus (HCV) with human immunodeficiency virus (HIV) has a higher risk of mortality than HCV or HIV monoinfection. HCV and HIV infections are specified by systemic inflammation, but the inflammation process in HCV/HIV coinfection is much complicated and is not well characterized. Objective: The aim of this study was to analyze the expression of TLR-3, TLR-7, IL-10, IFN-1 (IFN-α, IFN-β), and TNF-α in HIV, HCV and HIV/HCV co-infected patients. Methods: Forty-five patients including HIV group (n=15), HCV group (n=15), HIV/HCV coinfection group (n=15) and healthy control group (n=15) participated. Peripheral blood mononuclear cells (PBMCs) were obtained. PBMC-RNA, HCV and HIV RNA were extracted from all subjects and cDNA was synthesized. The viral load analyzed by reverse transcription-quantitative PCR (RT-qPCR), and the expression levels of IFN-α, IFN-β, TLR-3, TLR-7, TNF, and IL-10 mRNA were quantified in PBMCs. Results: The levels of IFN-I, IL-10, and TNF-α were overexpressed in all patients’ groups (P<0.05), TLR-7 was upregulated in all groups, but this upregulation was not statistically significant (p>0.05). TLR-3 showed a decrease in all patient groups (P<0.05). The statistical analysis demonstrated that TLR-3 has a negative correlation with HIV load, whereas other genes positively correlated with HIV load. In addition, TLR-3, TNF-α, and IFN-I were negatively correlated with HCV load, whereas TLR-7 and IL-10 s were positively correlated with HCV load. Conclusion: Our results showed a significant relationship between the expression level of innate immunity genes and inflammation in HCV, HIV, and HIV/HCV coinfected patients.

scholarly journals Duck RIG-I CARD Domain Induces the Chicken IFN-βby Activating NF-κB

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Yang Chen ◽  
Zhengyang Huang ◽  
Bin Wang ◽  
Qinming Yu ◽  
Ran Liu ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Eukaryotic Expression ◽  
Poly I:C ◽  
Expression Vectors ◽  
Luciferase Reporter ◽  
Enzyme Linked Immunosorbent Assay ◽  
Regulatory Domains ◽  
Polycytidylic Acid ◽  
Card Domain ◽  
Inducible Gene

Retinoic acid-inducible gene I- (RIG-I-) like receptors (RLRs) have recently been identified as cytoplasmic sensors for viral RNA. RIG-I, a member of RLRs family, plays an important role in innate immunity. Although previous investigations have proved that RIG-I is absent in chickens, it remains largely unknown whether the chicken can respond to RIG-I ligand. In this study, the eukaryotic expression vectors encoding duRIG-I full length (duck RIG-I, containing all domains), duRIG-I N-terminal (containing the two caspase activation and recruitment domain, CARDs), and duRIG-I C-terminal (containing helicase and regulatory domains) labeled with 6*His tags were constructed successfully and detected by western blotting. Luciferase reporter assay and enzyme-linked immunosorbent assay (ELISA) detected the duRIG-I significantly activated NF-κB and induced the expression of IFN-βwhen polyinosinic-polycytidylic acid (poly[I:C], synthetic double-stranded RNA) challenges chicken embryonic fibroblasts cells (DF1 cells), while the duRIG-I was inactive in the absence of poly[I:C]. Further analysis revealed that the CARDs (duRIG-I-N) induced IFN-βproduction regardless of the presence of poly[I:C], while the CARD-lacking duRIG-I (duRIG-I-C) was not capable of activating downstream signals. These results indicate that duRIG-I CARD domain plays an important role in the induction of IFN-βand provide a basis for further studying the function of RIG-I in avian innate immunity.

IL-1β and TNF-α Regulate IL-6-type Cytokines in Gingival Fibroblasts

2008 ◽  
Vol 87 (6) ◽  
pp. 558-563 ◽  
Author(s):  
P. Palmqvist ◽  
P. Lundberg ◽  
I. Lundgren ◽  
L. Hänström ◽  
U.H. Lerner
Keyword(s):  
Tumor Necrosis Factor ◽  
Interleukin 6 ◽  
Leukemia Inhibitory Factor ◽  
Tumor Necrosis ◽  
Map Kinases ◽  
Tumor Necrosis Factor Receptor ◽  
Oncostatin M ◽  
Gingival Fibroblasts ◽  
Tnf Α ◽  
Necrosis Factor

Interleukin-6 (IL-6)-type cytokines are pleiotropic molecules capable of stimulating bone resorption and expressed by numerous cell types. In the present study, we tested the hypothesis that gingival fibroblasts may exert local osteotropic effects through production of IL-6 and related cytokines. IL-6-type cytokine expression and regulation by IL-1β and tumor necrosis factor-α (TNF-α) were studied in fibroblasts from the non-inflamed gingiva of healthy individuals. Constitutive mRNA expression of IL-6, IL-11, and leukemia inhibitory factor (LIF), but not of oncostatin M (OSM), was demonstrated, as was concentration-dependent stimulation of IL-6 and LIF mRNA and of protein by IL-1β and TNF-α. IL-11 mRNA and protein were concentration-dependently stimulated by IL-1β. The signaling pathway involved in IL-6 and LIF mRNA stimulation involved MAP kinases, but not NF-κB. The findings support the view that resident cells may influence the pathogenesis of periodontal disease through osteotropic IL-6-type cytokine production mediated by activation of MAP kinases. Abbreviations: IL-1α (interleukin-1α); IL-1β (interleukin-1β); IL-6 (interleukin-6); IL-11 (interleukin-11); LIF (leukemia inhibitory factor); OSM (oncostatin M); α(1)-coll. I (α(1)-collagen I); ALP (alkaline phosphatase); BMP-2 (bone morphogenetic protein-2); OC (osteocalcin); BSP (bone sialoprotein); TNFR I (tumor necrosis factor receptor I); TNFR II (tumor necrosis factor receptor II); IL-1R1 (interleukin-1 receptor 1); GAPDH (glyceraldehyde-3-phosphate dehydrogenase); RPL13A (ribosomal protein L13A); mRNA (messenger ribonucleic acid); cDNA (complementary deoxyribonucleic acid); PCR (polymerase chain-reaction); BCA (bicinchoninic acid); ELISA (enzyme-linked immunosorbent assay); α-MEM (α modification of Minimum Essential Medium); and FCS (fetal calf serum).

scholarly journals Activation of Nuclear Factor κb and bcl-x Survival Gene Expression by Nerve Growth Factor Requires Tyrosine Phosphorylation of IκBα

2001 ◽  
Vol 152 (4) ◽  
pp. 753-764 ◽  
Author(s):  
Nguyen Truc Bui ◽  
Antonia Livolsi ◽  
Jean-Francois Peyron ◽  
Jochen H.M. Prehn
Keyword(s):  
Gene Expression ◽  
Tyrosine Phosphorylation ◽  
Fluorescent Protein ◽  
Nuclear Translocation ◽  
Nuclear Factor Κb ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Nuclear Factor ◽  
Human Neuroblastoma ◽  
Tnf Α

NGF has been shown to support neuron survival by activating the transcription factor nuclear factor-κB (NFκB). We investigated the effect of NGF on the expression of Bcl-xL, an anti–apoptotic Bcl-2 family protein. Treatment of rat pheochromocytoma PC12 cells, human neuroblastoma SH-SY5Y cells, or primary rat hippocampal neurons with NGF (0.1–10 ng/ml) increased the expression of bcl-xL mRNA and protein. Reporter gene analysis revealed a significant increase in NFκB activity after treatment with NGF that was associated with increased nuclear translocation of the active NFκB p65 subunit. NGF-induced NFκB activity and Bcl-xL expression were inhibited in cells overexpressing the NFκB inhibitor, IκBα. Unlike tumor necrosis factor-α (TNF-α), however, NGF-induced NFκB activation occurred without significant degradation of IκBs determined by Western blot analysis and time-lapse imaging of neurons expressing green fluorescent protein–tagged IκBα. Moreover, in contrast to TNF-α, NGF failed to phosphorylate IκBα at serine residue 32, but instead caused significant tyrosine phosphorylation. Overexpression of a Y42F mutant of IκBα potently suppressed NFG-, but not TNF-α–induced NFκB activation. Conversely, overexpression of a dominant negative mutant of TNF receptor-associated factor-6 blocked TNF-α–, but not NGF-induced NFκB activation. We conclude that NGF and TNF-α induce different signaling pathways in neurons to activate NFκB and bcl-x gene expression.

scholarly journals Tumor Necrosis Factor α Regulates Responses to Nerve Growth Factor, Promoting Neural Cell Survival but Suppressing Differentiation of Neuroblastoma Cells

2008 ◽  
Vol 19 (3) ◽  
pp. 855-864 ◽  
Author(s):  
Yoshinori Takei ◽  
Ronald Laskey
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Α ◽  
Neuroblastoma Cells ◽  
Erk Activation ◽  
Tnf Α ◽  
Factor Α ◽  
Necrosis Factor

Although nerve growth factor (NGF) promotes survival of neurons, tumor necrosis factor α (TNF-α) contributes to cell death triggered by NGF depletion, through TNF-α receptor (TNFR) 1. In contrast to this effect, TNF-α can promote neural cell survival via TNF-α receptor TNFR2. Although these findings demonstrate pivotal roles of TNF-α and NGF in cell fate decisions, cross-talk between these signaling pathways has not been clarified. We find that NGF can induce TNF-α synthesis through the nuclear factor-κB transcription factor. This provides a new basis for examining the cross-talk between NGF and TNF-α. Inhibition of TNFR2 shows opposite effects on two downstream kinases of NGF, extracellular signal-regulated kinase (Erk) and Akt. It increases Erk activation by NGF, and this increased activation induces differentiation of neuroblastoma cell lines. Reciprocally, inhibition of TNFR2 decreases Akt activation by NGF. Consistent with an essential role of Akt in survival signaling, inhibition of TNF-α signaling decreases NGF-dependent survival of neurons from rat dorsal root ganglia. Thus, NGF and NGF-induced TNF-α cooperate to activate Akt, promoting survival of normal neural cells. However, the NGF-induced TNF-α suppresses Erk activation by NGF, blocking NGF-induced differentiation of neuroblastoma cells. TNFR2 signaling could be a novel target to modulate cell responses to NGF.

Differential Mechanisms of Plasminogen Activator Inhibitor-1 Gene Activation by Transforming Growth Factor-β and Tumor Necrosis Factor-α in Endothelial Cells

2001 ◽  
Vol 86 (12) ◽  
pp. 1563-1572 ◽  
Author(s):  
Yan Chen ◽  
Joanne Sloan-Lancaster ◽  
David Berg ◽  
Mark Richardson ◽  
Brian Grinnell ◽  
...  
Keyword(s):  
Map Kinases ◽  
Transforming Growth Factor ◽  
Gene Activation ◽  
Plasminogen Activator Inhibitor ◽  
Transforming Growth Factor Β ◽  
Promoter Activation ◽  
Plasminogen Activator Inhibitor 1 ◽  
Tnf Α ◽  
Factor Α ◽  
Pai 1

SummaryPlasminogen activator inhibitor-1 (PAI-1) is a serine protease inhibitor (SERPIN) specific for tissue-type and urokinase-like plasminogen activators. High plasma PAI-1 activity is a risk factor for thrombotic diseases. Due to the short half-life of PAI-1, regulation of PAI-1 gene expression and secretion of active PAI-1 into the blood stream is important for hemostatic balance. We have investigated transcriptional control of PAI-1 gene expression in bovine aortic endothelial cells (BAECs) and human cell lines using PAI-1 5’ promoter-luciferase reporter assays. Contrary to the cytokine-induced up-regulation of PAI-1 mRNA and protein levels, we found that only transforming growth factor-β (TGF-β) was efficient in inducing PAI-1 promoter activation. Tissue necrosis factor-α (TNF-α) induced a small luciferase activity with the 2.5 kb PAI-1 promoter, but not with the PAI-800/4G/5G and p3TP-lux promoters. Next we investigated whether a lack of response to TNF-α was due to deficient signaling pathways. BAECs responded to TNF-α with robust NFκB promoter activation. TGF-β activated the p38 MAP kinase, while TNF-α activated both the SAPK/JNK and p38 MAP kinases. The ERK1/2 MAP kinases were constitutively activated in BAECs. BAEC therefore responded to TNF-α stimulation with activation of the MAP kinases and the NFκB transcriptional factors. We further measured the messenger RNA stability under the influence by TGF-β and TNF-α and found no difference. PAI-1 gene activation by TNF-α apparently is yet to be defined for the location of the response element and/or the signaling pathway, while TGF-β is the most important cytokine for PAI-1 transcriptional activation through its 5’ proximal promoter.

Sign in / Sign up

Export Citation Format

Share Document