scholarly journals Upregulated Expression of Toll-Like Receptor 4 in Monocytes Correlates with Severity of Acute Cerebral Infarction

2008 ◽  
Vol 28 (9) ◽  
pp. 1588-1596 ◽  
Author(s):  
Qing-wu Yang ◽  
Jing-cheng Li ◽  
Feng-lin Lu ◽  
Wen Ai-qing ◽  
Jing Xiang ◽  
...  
Keyword(s):  
Cerebral Infarction ◽  
Cerebral Edema ◽  
Gene Knockout ◽  
Signal Pathway ◽  
Control Group ◽  
Toll Like Receptor ◽  
Tlr4 Expression ◽  
Toll Like Receptor 4 ◽  
Neurologic Impairment ◽  
Gene Knockout Mice

In the present study, we observed the expression of toll-like receptor 4 (TLR4) and its downstream signal pathway in peripheral blood monocytes (PBMs) from patients with acute cerebral infarct (ACI). The expression of TLR4 and MyD88 by PBMs was determined by flow cytometry and reverse transcriptase-polymerase chain reaction, and nuclear factor-κB (NF-κB) activity was detected by electrophoretic mobility shift assay. Ischemia/reperfusion injury-induced cerebral edema, infarction area, and neurologic impairment scores were determined in MyD88 gene knockout mice. The results indicated a significant increase in circulating TLR4+ monocytes in ACI patients as compared with the control group and the transient ischemia attack (TIA) group. This change paralleled an elevation in TLR4mRNA transcription and serum tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 in the ACI and TIA groups. Correlation analysis showed TLR4 expression to significantly correlate with cytokine levels and stroke severity. MyD88mRNA differed insignificantly among the three groups. Compared with wild-type mice, 6 h of cerebral ischemia followed by 24 h of reperfusion did not significantly change cerebral edema, cerebral infarction area, and neurologic impairment scores in MyD88 gene knockout mice. Compared with the control group, serum heat shock protein (HSP) 60 increased significantly in the ACI and TIA groups, leading to NF-κB activation in TLR4/CD14-transfected HEK293 cells. It is suggested that upregulated TLR4 expression on PMBs may act as one of the peripheral mechanisms of inflammatory injury after ACI. Moreover, circulating HSP60 may be a ligand for TLR4, which is involved in the peripheral mechanism of inflammatory injury after ACI, possibly through an MyD88-independent signal pathway.

scholarly journals Intestinal Epithelial Toll-Like Receptor 4 Signaling Affects Epithelial Function and Colonic Microbiota and Promotes a Risk for Transmissible Colitis

2016 ◽  
Vol 84 (3) ◽  
pp. 798-810 ◽  
Author(s):  
Rishu Dheer ◽  
Rebeca Santaolalla ◽  
Julie M. Davies ◽  
Jessica K. Lang ◽  
Matthew C. Phillips ◽  
...  
Keyword(s):  
Intestinal Inflammation ◽  
Gene Knockout ◽  
Intestinal Bacteria ◽  
Intestinal Epithelial ◽  
Toll Like Receptor ◽  
Tlr4 Expression ◽  
Toll Like Receptor 4 ◽  
Tlr4 Signaling ◽  
Altered Expression ◽  
Innate Immune Signaling

Evidence obtained from gene knockout studies supports the role of Toll-like receptor 4 (TLR4) in intestinal inflammation and microbiota recognition. Increased epithelial TLR4 expression is observed in patients with inflammatory bowel disease. However, little is known of the effect of increased TLR4 signaling on intestinal homeostasis. Here, we examined the effect of increased TLR4 signaling on epithelial function and microbiota by using transgenic villin-TLR4 mice that overexpress TLR4 in the intestinal epithelium. Our results revealed that villin-TLR4 mice are characterized by increases in the density of mucosa-associated bacteria and bacterial translocation. Furthermore, increased epithelial TLR4 signaling was associated with an impaired epithelial barrier, altered expression of antimicrobial peptide genes, and altered epithelial cell differentiation. The composition of the colonic luminal and mucosa-associated microbiota differed between villin-TLR4 and wild-type (WT) littermates. Interestingly, WT mice cohoused with villin-TLR4 mice displayed greater susceptibility to acute colitis than singly housed WT mice did. The results of this study suggest that epithelial TLR4 expression shapes the microbiota and affects the functional properties of the epithelium. The changes in the microbiota induced by increased epithelial TLR4 signaling are transmissible and exacerbate dextran sodium sulfate-induced colitis. Together, our findings imply that host innate immune signaling can modulate intestinal bacteria and ultimately the host's susceptibility to colitis.

Association of the CD14 C159T and the Toll-like receptor 4 Asp299Gly polymorphisms with various phenotypes of asthma in adults from Crimea

2020 ◽  
Vol 41 (2) ◽  
pp. 134-140
Author(s):  
Yuriy Bisyuk ◽  
Andrew Dubovyi ◽  
Ilona DuBuske ◽  
Viktor Litus ◽  
Lawrence M. DuBuske
Keyword(s):  
Late Onset ◽  
Adult Population ◽  
Additive Models ◽  
Atopic Asthma ◽  
Control Group ◽  
Nucleotide Polymorphisms ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Single Nucleotide ◽  
Gender And Age

Background: This study assessed gene polymorphisms of the CD14 receptor (C-159T) and Toll-like receptor 4 (Asp299Gly) in a patient population in Crimea, Ukraine, stratified by clinical (early versus late onset; frequent versus occasional relapses; fixed versus reversible obstruction) and immunologic (atopic versus nonatopic; eosinophilic; neutrophilic or paucigranulocytic inflammation) subtype. Methods: Two polymorphisms, CD14 C-159T and TLR4 Asp299Gly, were assessed in 331 patients with asthma. The control group included 285 volunteers who were nonatopic. The single nucleotide polymorphisms were studied by using polymerase chain reaction with electrophoretic detection. Results: There were increased odds of asthma development in patients with the Asp299Gly TLR4 mutation compared with the general population underdominant odds ratio (OR) 1.52 [95% confidence interval (CI), 1.00‐2.32] and overdominant (OR 1.55 [95% CI, 1.01‐2.38]) models after adjustment for gender and age. In addition, mutations in this gene decreased the odds of nonatopic asthma in underdominant (OR 0.26 [95% CI, 0.07‐0.93]; p = 0.027), overdominant (OR 0.27 [95% CI, 0.07‐0.96]; p = 0.033), and log-additive models (OR 0.26 [95% CI, 0.07‐0.93]; p = 0.026) compared with the atopic subgroup after adjustment for gender, age, number of exacerbations, and type of airway inflammation. Allele frequencies for CD14 and TLR4 polymorphisms did not show statistical differences between the patients with asthma and the control subjects. Conclusion: CD14 C-159T polymorphisms were not associated with asthma in the adult population in Crimea. TLR4 Asp299Gly polymorphisms were associated with asthma and with decreased odds of nonatopic asthma compared with atopic asthma in the adult population in Crimea.

scholarly journals FTO (Fat-Mass and Obesity-Associated Protein) Participates in Hemorrhage-Induced Thalamic Pain by Stabilizing Toll-Like Receptor 4 Expression in Thalamic Neurons

Stroke ◽  
2021 ◽  
Author(s):  
Ganglan Fu ◽  
Shibin Du ◽  
Tianfeng Huang ◽  
Minghui Cao ◽  
Xiaozhou Feng ◽  
...  
Keyword(s):  
Fat Mass ◽  
Rna Binding ◽  
Intraperitoneal Administration ◽  
Toll Like Receptor ◽  
Tlr4 Expression ◽  
Toll Like Receptor 4 ◽  
Thalamic Neurons ◽  
Adeno Associated Virus ◽  
Meclofenamic Acid ◽  
Thalamic Pain

Background and Purpose: Hemorrhage-caused gene changes in the thalamus likely contribute to thalamic pain genesis. RNA N 6 -methyladenosine modification is an additional layer of gene regulation. Whether FTO (fat-mass and obesity-associated protein), an N 6 -methyladenosine demethylase, participates in hemorrhage-induced thalamic pain is unknown. Methods: Expression of Fto mRNA and protein was assessed in mouse thalamus after hemorrhage caused by microinjection of Coll IV (type IV collagenase) into unilateral thalamus. Effect of intraperitoneal administration of meclofenamic acid (a FTO inhibitor) or microinjection of adeno-associated virus 5 (AAV5) expressing Cre into the thalamus of Fto fl/fl mice on the Coll IV microinjection–induced TLR4 (Toll-like receptor 4) upregulation and nociceptive hypersensitivity was examined. Effect of thalamic microinjection of AAV5 expressing Fto (AAV5- Fto ) on basal thalamic TLR4 expression and nociceptive thresholds was also analyzed. Additionally, level of N 6 -methyladenosine in Tlr4 mRNA and its binding to FTO or YTHDF2 (YTH N 6 -methyladenosine RNA binding protein 2) were observed. Results: FTO was detected in neuronal nuclei of thalamus. Level of FTO protein, but not mRNA, was time-dependently increased in the ipsilateral thalamus on days 1 to 14 after Coll IV microinjection. Intraperitoneal injection of meclofenamic acid or adeno-associated virus-5 expressing Cre microinjection into Fto fl/fl mouse thalamus attenuated the Coll IV microinjection–induced TLR4 upregulation and tissue damage in the ipsilateral thalamus and development and maintenance of nociceptive hypersensitivities on the contralateral side. Thalamic microinjection of AAV5- Fto increased TLR4 expression and elicited hypersensitivities to mechanical, heat and cold stimuli. Mechanistically, Coll IV microinjection produced an increase in FTO binding to Tlr4 mRNA, an FTO-dependent loss of N 6 -methyladenosine sites in Tlr4 mRNA and a reduction in the binding of YTHDF2 to Tlr4 mRNA in the ipsilateral thalamus. Conclusions: Our findings suggest that FTO participates in hemorrhage-induced thalamic pain by stabilizing TLR4 upregulation in thalamic neurons. FTO may be a potential target for the treatment of this disorder.

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 Expressions of TOLL-like receptor 4 (TLR-4) and matrix metalloproteinase 9 (MMP-9)/Tissue inhibitor of metalloproteinase 1 (TIMP-1) in pulmonary blood vessels with chronic obstructive pulmonary diseases and their relationships with pulmonary vascular remodelling

2018 ◽  
Vol 64 (4) ◽  
pp. 361-367 ◽  
Author(s):  
Wen-Cheng Yu ◽  
Jin-Peng Cong ◽  
Li-Yun Mi
Keyword(s):  
Smooth Muscle ◽  
Matrix Metalloproteinase ◽  
Tissue Inhibitor Of Metalloproteinase ◽  
Control Group ◽  
Chronic Obstructive ◽  
Toll Like Receptor ◽  
Vascular Remodelling ◽  
Toll Like Receptor 4 ◽  
Metalloproteinase 9 ◽  
Pulmonary Vascular Remodelling

SUMMARY OBJECTIVE: This study aims at investigating the expressions of TOLL-like receptor 4 (TLR-4) and matrix metalloproteinase 9 (MMP-9)/ tissue inhibitor of metalloproteinase 1 (TIMP-1) in pulmonary blood vessels with chronic obstructive pulmonary disease (COPD) and their relationships with pulmonary vascular remodelling (PVR). METHODS: 60 para-tumour tissues were divided into the COPD group and the control group (n=30); the inflammations, pulmonary artery wall area/total artery area (WA%), and wall thickness/vascular outer diameter (WT%) were compared. The expressions of TLR-4, MMP-9/TIMP-1, and PCNA in pulmonary vascular smooth muscle cells were detected, and their relationships with PVR were then analysed. RESULTS: The inflammations (1.6±0.8), WA% (44.0±6.4), and WT% (27.3±3.3) in the COPD group were higher than in the control group (0.3±0.5, 26.1±2.8, 15.6±1.8), and the expressions of TLR-4 (31.4±147) and MMP-9/TIMP-1 (2.2±2.6) were increased compared to the control group (4.7±4.5, 1.9±12). Correlation analysis: TLR-4 and MMP-9/TIMP-1 were positively correlated with the inflammations (r=0.18, P<0.01), WA% (r=0.68, P<0.01), and WT% (r=0.73, P<0.01), as well as positively correlated with the expression of PCNA (r=0.44, P<0.01); the upregulation of TLR-4 was positively correlated with the expressions of MMP-9 and TIMP-1. CONCLUSIONS: The upregulation of TLR-4 in the pulmonary arterial smooth muscle cells of COPD patients could promote the inflammations and the MMP-9 expression, thus causing abnormal degradation of extracellular matrix, so it played an important role in the process of PVR.

scholarly journals Toll-Like Receptor 4 (TLR4) Expression Affects Schwann Cell Behavior in vitro

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Huanhuan Zhang ◽  
Zhiwei Shao ◽  
Yun Zhu ◽  
Lingyu Shi ◽  
Zhihao Li ◽  
...  
Keyword(s):  
Schwann Cell ◽  
Cell Behavior ◽  
Toll Like Receptor ◽  
Tlr4 Expression ◽  
Toll Like Receptor 4

scholarly journals Downregulation of Lung Toll-Like Receptor 4 Could Effectively Attenuate Liver Transplantation-Induced Pulmonary Damage at the Early Stage of Reperfusion

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Xinjin Chi ◽  
Weifeng Yao ◽  
Ailan Zhang ◽  
Mian Ge ◽  
Jun Cai ◽  
...  
Keyword(s):  
Liver Transplantation ◽  
Polymorphonuclear Leukocytes ◽  
Early Stage ◽  
Pulmonary Inflammation ◽  
Toll Like Receptor ◽  
Tlr4 Expression ◽  
Toll Like Receptor 4 ◽  
Pulmonary Damage ◽  
Autologous Liver

Acute lung injury (ALI) is a severe complication of orthotopic liver transplantation (OLT) with unclear underline mechanism. Toll-like receptor 4 (TLR4) has been identified as a key receptor mediating inflammation. We hypothesized that TLR4-mediated pulmonary inflammation may contribute to development of ALI during OLT. Patients with or without ALI were observed for serum cytokines and expression of TLR4 on peripheral blood polymorphonuclear leukocytes (PMNs). Next, rats which underwent orthotopic autologous liver transplantation (OALT) were divided into sham and model groups. Pulmonary function and the level of TLR4 expression and cytokines were analyzed. Furthermore, the role of TLR4 in OALT-mediated ALI was assessed in rats treated with TLR4-siRNA before OALT. The PMNs TLR4 expression and the serum TNF-αand IL-βlevel were higher in patients with ALI than those with non-ALI. Interestingly, lung TLR4 expression was significantly increased after 8 hours of OALT with increased levels of TNF-αand IL-β, which lead to lung pathological damage and an increase of lung myeloperoxidase content. Moreover, knockdown of TLR4 reduced lung cytokines release and reversed the above pathologic changes after OALT and finally improved rats’ survival rate. In conclusion, TLR4 overexpression, potentially by stimulating proinflammatory cytokine overproduction, contributes to the development of ALI after OLT.

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