scholarly journals Expression of Toll-Like Receptor 4 in Glomerular Endothelial Cells under Diabetic Conditions

2013 ◽  
Vol 46 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Shunsuke Takata ◽  
Yoshihiko Sawa ◽  
Takanobu Uchiyama ◽  
Hiroyuki Ishikawa
Keyword(s):  
Endothelial Cells ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Glomerular Endothelial Cells

scholarly journals TNF-α Activates High-Mobility Group Box 1 - Toll-Like Receptor 4 Signaling Pathway in Human Aortic Endothelial Cells

2016 ◽  
Vol 38 (6) ◽  
pp. 2139-2151 ◽  
Author(s):  
Won Seok Yang ◽  
Nam Jeong Han ◽  
Jin Ju Kim ◽  
Mee Jeong Lee ◽  
Su-Kil Park
Keyword(s):  
Signal Transduction ◽  
Endothelial Cells ◽  
High Mobility ◽  
Neutralizing Antibody ◽  
High Mobility Group ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Aortic Endothelial Cells ◽  
Tnf Α ◽  
Human Aortic Endothelial Cells

Background/Aims: Toll-like receptor 4 (TLR4) interacts with endogenous substances as well as lipopolysaccharide. We explored whether TLR4 is implicated in tumor necrosis factor-α (TNF-α) signal transduction in human aortic endothelial cells. Methods: The pathway was evaluated by transfection of siRNAs, immunoprecipitation and Western blot analysis. Results: TNF-α activated spleen tyrosine kinase (Syk) within 10 min, which led to endothelin-1 (ET-1) production. TLR4 was also rapidly activated by TNF-α stimulation, as shown by recruitment of interleukin-1 receptor-associated kinase 1 to TLR4 and its adaptor molecule, myeloid differentiation factor 88 (MyD88). siRNA depletion of TLR4 markedly attenuated TNF-α-induced Syk activation and ET-1 production. TLR4 inhibitor (CLI-095), TLR4-neutralizing antibody and siRNA depletion of MyD88 also attenuated TNF-α-induced Syk activation. Syk was co-immunoprecipitated with TLR4, and TNF-α activated Syk bound to TLR4. High-mobility group box 1 (HMGB1) was rapidly released and associated with TLR4 after TNF-α stimulation with a peak at 5 min, which was prevented by N-acetylcysteine, an antioxidant. Glycyrrhizin (HMGB1 inhibitor), HMGB1-neutralizing antibody and siRNA depletion of HMGB1 all suppressed TNF-α-induced Syk activation and ET-1 production. Conclusion: Upon TNF-α stimulation, TLR4 is activated by HMGB1 that is immediately released after the generation of reactive oxygen species, and plays a crucial role in the signal transduction.

scholarly journals ADAM17-Mediated Ectodomain Shedding of Toll-Like Receptor 4 as a Negative Feedback Regulation in Lipopolysaccharide-Activated Aortic Endothelial Cells

2018 ◽  
Vol 45 (5) ◽  
pp. 1851-1862 ◽  
Author(s):  
Won Seok Yang ◽  
Jin Ju Kim ◽  
Mee Jeong Lee ◽  
Eun Kyoung Lee ◽  
Su-Kil Park
Keyword(s):  
Endothelial Cells ◽  
P38 Mapk ◽  
Ectodomain Shedding ◽  
Toll Like Receptor ◽  
Tlr4 Expression ◽  
Toll Like Receptor 4 ◽  
Negative Feedback Regulation ◽  
Mapk Activation ◽  
Aortic Endothelial Cells ◽  
Aortic Endothelial

Background/Aims: Lipopolysaccharide (LPS)-activated monocytes/macrophages develop endotoxin tolerance in part by reducing cell surface toll-like receptor 4 (TLR4) through cluster of differentiation 14 (CD14)-dependent endocytosis. In case of endothelial cells, CD14 is expressed in low copy numbers as compared with monocytes/macrophages. Thus, we explored how endothelial cells regulate TLR4 expression after LPS stimulation. Methods: Cultured human aortic endothelial cells (HAECs) were treated with LPS. TLR4 expression was analyzed by Western blot analysis and immunofluorescence staining. A disintegrin and metalloprotease 17 (ADAM17) activity was measured using a fluorescent substrate. Results: TLR4 in cell lysate began to decrease within 30 min of LPS treatment with a maximal reduction at 2 h, and it was accompanied by an increase of N-terminal fragment of TLR4 in culture supernatant, indicating ectodomain shedding of the receptor. LPS activated p38 mitogen-activated protein kinase (p38 MAPK) and ADAM17, while LPS-induced ADAM17 activation was inhibited by SB203580, a p38 MAPK inhibitor. LPS-induced ectodomain shedding of TLR4 was attenuated by siRNA depletion of ADAM17 as well as TAPI-2 (an inhibitor of ADAM family) and SB203580. LPS pretreatment resulted in a blunted response of p38 MAPK activation to further LPS stimulation. In the cells depleted of ADAM17, LPS-induced p38 MAPK activation was prolonged and LPS-induced intercellular adhesion molecule-1 expression was potentiated. Conclusion: HAECs respond to LPS by rapid shedding of the ectodomain of TLR4 and thereby reduce the responsiveness to subsequent LPS exposure. ADAM17, downstream of p38 MAPK, is implicated in the ectodomain cleavage of TLR4.

scholarly journals Cytosolic Sensors of Viral RNA Are Involved in the Production of Interleukin-6 via Toll-Like Receptor 3 Signaling in Human Glomerular Endothelial Cells

2019 ◽  
Vol 44 (1) ◽  
pp. 62-71 ◽  
Author(s):  
Qiang Liu ◽  
Tadaatsu Imaizumi ◽  
Tomomi Aizawa ◽  
Koji Hirono ◽  
Shogo Kawaguchi ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Signaling Pathway ◽  
Interleukin 6 ◽  
Viral Rna ◽  
Pivotal Role ◽  
Toll Like Receptor ◽  
Polycytidylic Acid ◽  
Glomerular Endothelial Cells ◽  
Human Glomerular Endothelial Cells ◽  
Tlr3 Signaling

Background/Aims: Dysregulation of interleukin-6 (IL-6) production in residual renal cells may play a pivotal role in the development of glomerulonephritis (GN). Given that Toll-like receptor 3 (TLR3) signaling has been implicated in the pathogenesis of some forms of GN, we examined activated TLR3-mediated IL-6 signaling in cultured normal human glomerular endothelial cells (GECs). Methods: We treated GECs with polyinosinic-polycytidylic acid (poly IC), an authentic double-stranded RNA, and analyzed the expression of IL-6 and the cytosolic viral RNA sensors retinoic acid-inducible gene-I (RIG-I) and melanoma differentiation associated gene 5 (MDA5) using reverse transcription quantitative real-time polymerase chain reaction, western blotting, and enzyme-linked immunosorbent assays. To further elucidate the effects of poly IC on this signaling pathway, we subjected the cells to small interfering RNA (siRNA) against TLR3, interferon (IFN)-β, RIG-I, and MDA5. Results: We found that poly IC induced the expression of RIG-I, MDA5 and IL-6 via TLR3/IFN-β signaling in GECs. siRNA experiments revealed that both MDA5 and RIG-I were involved in the poly IC-induced expression of IL-6, with MDA5 being upstream of RIG-I. Conclusion: Interestingly, cytosolic sensors of viral RNA were found to be involved in IL-6 production via TLR3 signaling in GECs. Regional activation of TLR3/IFN-β/ MDA5/RIG-I/IL-6 axis due to viral and “pseudoviral” infections is involved in innate immunity and inflammatory reactions in GECs. We believe this signaling pathway also plays a pivotal role in the development of some forms of GN.

scholarly journals Double-Stranded DNA Activates Glomerular Endothelial Cells and Enhances Albumin Permeability via a Toll-Like Receptor-Independent Cytosolic DNA Recognition Pathway

2009 ◽  
Vol 175 (5) ◽  
pp. 1896-1904 ◽  
Author(s):  
Holger Hägele ◽  
Ramanjaneyulu Allam ◽  
Rahul D. Pawar ◽  
Christoph A. Reichel ◽  
Fritz Krombach ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Dna Recognition ◽  
Toll Like Receptor ◽  
Double Stranded Dna ◽  
Glomerular Endothelial Cells

Atorvastatin suppresses LPS-induced rapid upregulation of Toll-like receptor 4 and its signaling pathway in endothelial cells

2011 ◽  
Vol 300 (5) ◽  
pp. H1743-H1752 ◽  
Author(s):  
Ying Wang ◽  
Ming Xiang Zhang ◽  
Xiao Meng ◽  
Fu Qiang Liu ◽  
Guang Sheng Yu ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Mrna Expression ◽  
Signaling Pathways ◽  
P38 Mapk ◽  
Umbilical Vein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Mapk Phosphorylation ◽  
Tlr4 Mrna

In the present study, we tested our hypothesis that atorvastatin exerts its anti-inflammation effect via suppressing LPS-induced rapid upregulation of Toll-like receptor 4 (TLR4) mRNA and its downstream p38, ERK, and NF-κB signaling pathways in human umbilical-vein endothelial cells (HUVECs) and human aortic endothelial cells (HAECs). TLR4 mRNA expression and its downstream kinase activities induced by LPS alone or atorvastatin + LPS in endothelial cells were quantified using quantitative real-time PCR and enzyme-linked immunosorbent assay. Preincubation of LPS-stimulated endothelial cells with TLR4 siRNA was conducted to identify the target of the anti-inflammatory effects of atorvastatin. Atorvastatin incubation resulted in the reduction of LPS-induced TLR4 mRNA expression, ERK1/2 and P38 MAPK phosphorylation, and NF-κB binding activity. Pretreatment with MEK/ERK1/2 inhibitor PD98059 attenuated atorvastatin + LPS-induced NF-κB activity but had no effect on P38 MAPK phosphorylation. In contrast, pretreatment with P38 MAPK inhibitor SB203580 resulted in upregulation of atorvastatin + LPS-induced ERK1/2 phosphorylation but had no significant effects on NF-κB activity. On the other hand, blocking NF-κB with SN50 produced no effects on atorvastatin + LPS-induced ERK1/2 and P38 MAPK phosphorylation. Moreover, TLR4 gene silencing produced the same effects as the atorvastatin treatment. In conclusion, atorvastatin downregulated TLR4 mRNA expression by two distinct signaling pathways. First, atorvastatin stabilized Iκ-Bα, which directly inhibited NF-κB activation. Second, atorvastatin inactivated ERK phosphorylation, which indirectly inhibited NF-κB activation. Suppression of p38 MAPK by atorvastatin upregulates ERK but exerts no effect on NF-κB.

399 INVOLVEMENT OF TOLL LIKE RECEPTOR-4 IN INFLAMMATORY RESPONSES OF ENDOTHELIAL CELLS

2011 ◽  
Vol 12 (1) ◽  
pp. 85
Author(s):  
R. Menghini ◽  
M. Tesauro ◽  
V. Rovella ◽  
A. Marino ◽  
R. Lauro ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Inflammatory Responses ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4

Toll-like receptor 4 and β2 glycoprotein I interaction on endothelial cells

Lupus ◽  
2014 ◽  
Vol 23 (12) ◽  
pp. 1302-1304 ◽  
Author(s):  
MO Borghi ◽  
E Raschi ◽  
C Grossi ◽  
CB Chighizola ◽  
PL Meroni
Keyword(s):  
Endothelial Cells ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Glycoprotein I

Toll-like receptor 4 mediates pro-inflammatory effects of visfatin on endothelial cells

2008 ◽  
Vol 32 (3) ◽  
pp. S17-S17
Author(s):  
Zhe Shi ◽  
De Jian Jiang ◽  
Qiong Yuan ◽  
Yuan Jian Li ◽  
Han Wu Deng
Keyword(s):  
Endothelial Cells ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4

Toll like Receptor 4 Is Involved in In VIvo Antiphospholipid-Mediated Thrombosis and Endothelial Cell Activation.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 133-133
Author(s):  
Silvia S. Pierangeli ◽  
Mariano E. Vega-Ostertag ◽  
Elena Raschi ◽  
Xiaowei Liu ◽  
Maria O. Borghi ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Antiphospholipid Syndrome ◽  
Cell Activation ◽  
Spontaneous Mutation ◽  
Toll Like Receptor ◽  
Endothelial Cell Activation ◽  
Toll Like Receptor 4 ◽  
Control Serum

Abstract Background: Antiphospholipid antibodies (aPL) are associated with thrombosis and pregnancy loss in patients with Antiphospholipid Syndrome (APS). aPL and bacterial lipopolysaccharide (LPS) bind to and activate endothelial cells (EC) through NFκB and p38 MAPK pathways. Recent studies suggest that aPL might interact with toll-like receptor-4 (TLR-4), the receptor for LPS. Aim: to investigate the role of TLR-4 in antiphospholipid syndrome (APS). Methods: we examined: i) the aPL effects on thrombosis and EC activation in LPS non-responsive (LPS−/−) mice that display a spontaneous mutation of TLR-4 vs LPS-responsive (LPS+/+) mice displaying wild type TLR-4, ii) the prevalence of TLR-4 Asp299gly and Thr399Ile polymorphisms - both associated with decreased response to LPS - in 110 APS patients (with arterial and/or venous thrombosis) vs 220 controls (of same ethnic background). IgGs were purified from a patient with APS (IgG-APS) and from control serum (IgG-NHS). LPS −/− and LPS +/+ mice, in groups of nine, were treated with IgG-APS or with IgG-NHS twice intraperitoneally. Size of induced thrombi and # of leukocyte (WBC) adhering to endothelial cells in the microcirculation of endothelium of the cremaster muscle of mice (as a means to measure endothelial cell activation) were determined in vivo, seventy-two hours after the first injection. TLR-4 Asp299gly & Thr399Ile polymorphisms were evaluated by Allele-Specific PCR. Results: LPS +/+ mice treated with IgG-APS produced significantly larger thrombi when compared to mice treated with IgG-NHS (2166 ± 1419 μm2 vs 1176 ± 841 μm2) and significantly larger number of WBC adherence to ECs (4.5 ± 1.9 vs 2.2 ±1.1). Thrombus size and number of adhering WBC to ECs were significantly lower in LPS −/− mice treated with IgG-APS compared to LPS +/+ mice treated with IgG-APS [thrombus size: 779 ± 628 μm2 vs 2166 ± 1419 μm2 (p<0.05) and number of adherent WBC to EC: 1.0 ± 0.5 vs 4.5 1.9 (p<0.05)], respectively. The titer of anticardiolipin antibodies in the sera of mice injected with aPL was 48.2 ± 17.1 GPL (for LPS −/− mice) and 50.8 ± 11.2 GPL (for LPS +/+ mice), respectively (NS). A significant reduction in TLR-4 Asp 299gly & Thr399Ile polymorphisms was observed in APS patients (5%) compared to controls (11.4%) (p<0.05). Conclusions: These findings strongly suggest that TLR-4 is involved in aPL interaction with endothelial cells and mediates their pathogenic effects.

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