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 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.

Statin treatment is associated with reduced toll-like receptor 4 immunohistochemical expression on carotid atherosclerotic plaques: a novel effect of statins

Vascular ◽  
2011 ◽  
Vol 19 (6) ◽  
pp. 320-326 ◽  
Author(s):  
Athanasios Katsargyris ◽  
Chris Klonaris ◽  
Sotirios Tsiodras ◽  
Elias Bastounis ◽  
Athanasios Giannopoulos ◽  
...  
Keyword(s):  
Carotid Plaque ◽  
Statin Treatment ◽  
Atherosclerotic Plaques ◽  
Toll Like Receptor ◽  
Tlr4 Expression ◽  
Immunohistochemical Expression ◽  
Toll Like Receptor 4 ◽  
Over Expression ◽  
Plaque Stabilization ◽  
Plaque Destabilization

Toll-like receptor 4 (TLR4) has been recently implicated in inflammatory pathways involved in carotid plaque destabilization. Given that statins have plaque stabilization and inflammation reduction effects, we investigated whether TLR4 expression on carotid atherosclerotic plaques correlates with statin intake. Carotid atherosclerotic plaques were obtained on 140 patients (preoperative statin intake, n = 70). TLR4 immunohistochemical expression was investigated in endothelial cells (ECs), macrophages (MACs) and smooth muscle cells (SMCs) of carotid atheroma. TLR4 positivity, over-expression and intensity of immunostaining were compared in statin versus no-statin users. The results of this study showed that statin users had a significantly lower expression of TLR4 in ECs ( P = 0.02, 0.001, 0.006 for TLR4 positivity, increased intensity and over-expression, respectively). Similarly, TLR4 positivity was less pronounced in carotid plaque MACs of statin users ( P = 0.03). No carotid specimen with increased EC TLR4 intensity or over-expression was observed among statin users. The prevalence of any cerebrovascular accident was 61.4% in the ‘no statin’ versus 18.6% in the ‘statin’ group (odds ratio for statin use: 0.14, 95% CI: 0.07–0.31, P < 0.001). In conclusion, statin treatment is associated with attenuated TLR4 expression on human carotid atherosclerotic plaques and a reduced risk of carotid-related cerebrovascular events. TLR4 may potentially mediate statins' plaque stabilization effects. Further investigation is necessary.

scholarly journals Toll-Like Receptor 4 as a Favorable Prognostic Marker in Bladder Cancer: A Multi-Omics Analysis

2021 ◽  
Vol 9 ◽  
Author(s):  
Jun-Lin Lu ◽  
Qi-Dong Xia ◽  
Yi Sun ◽  
Yang Xun ◽  
Heng-Long Hu ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
Survival Rate ◽  
Prognostic Marker ◽  
Promoter Methylation ◽  
Methylation Level ◽  
Prognostic Value ◽  
Toll Like Receptor ◽  
Tlr4 Expression ◽  
Toll Like Receptor 4 ◽  
Tumor Tissues

BackgroundThe toll-like receptor 4 (TLR4) agonist, Bacille Calmette-Guérin, has exhibited gratifying effects in treating bladder cancer. The study aims to explore the expression pattern, prognostic value, and potential mechanism of TLR4 in bladder cancer.MethodsThe transcriptome file from the GSE13507 dataset in the Gene Expression Omnibus database and the promoter methylation file from the bladder cancer dataset in The Cancer Genome Atlas database were downloaded for analysis. The prognostic value of the TLRs was assessed by univariate Cox regression. Immunohistochemistry was applied to verify the expression of TLR4 in bladder cancer. The drug response is estimated through the R package “pRRophetic.” The CIBERSORT algorithm was carried out to estimate the infiltrating immune cells of samples. Gene Set Enrichment Analysis (GSEA) was performed to identify the pathways involved under varied TLR4 expression levels.ResultsTLR4 is decreased in tumor tissues compared with surrounding tumor tissues or normal tissue, which is also positively correlated to the overall survival rate (hazard ratio [HR] = 0.38) and cancer-specific survival rate (HR = 0.15) of patients with bladder cancer. Low expression of TLR4 is observed in tumors with malignant performance (high pathological grade, higher tumor stage, and progression). Patients with low TLR4 levels are more sensitive to gemcitabine rather than cisplatin. The promoter methylation level of TLR4 is positively associated with TLR4 expression (P &lt; 0.001). The cg14629571 methylation site largely contributes to the overall methylation level. The CIBERSORT analysis shows that high TLR4 expression is associated with lower levels of plasma cells, M0 macrophages, and M1 macrophages. The GSEA results indicate that the TGF-β pathway and apoptosis are activated in high TLR4 bladder cancer, while G2M checkpoint and E2F targets pathways are enriched in low TLR4 bladder cancer.ConclusionThis research discusses the abnormal expression and prognostic value of TLR4 in bladder cancer. The TLR4 expression can effectively predict oncological outcomes and drug sensitivity of bladder cancer patients. TLR4 is also associated with infiltrating immune cell variation and cancer pathway dysregulation. The results provide a novel prognostic marker and potential drug targets for bladder cancer.

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 Toll-Like Receptor 4 Reduces Oxidative Injury via Glutathione Activity in Sheep

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Shoulong Deng ◽  
Kun Yu ◽  
Qian Wu ◽  
Yan Li ◽  
Xiaosheng Zhang ◽  
...  
Keyword(s):  
Oxidative Injury ◽  
Innate Immune ◽  
Gram Negative Bacteria ◽  
Superoxide Dismutase 1 ◽  
Toll Like Receptor ◽  
Tlr4 Expression ◽  
Toll Like Receptor 4 ◽  
Transgenic Sheep ◽  
Glutamylcysteine Synthetase ◽  
Inflammatory Infiltrates

Toll-like receptor 4 (TLR4) is an important sensor of Gram-negative bacteria and can trigger activation of the innate immune system. Increased activation of TLR4 can lead to the induction of oxidative stress. Herein, the pathway whereby TLR4 affects antioxidant activity was studied. In TLR4-overexpressing sheep, TLR4 expression was found to be related to the integration copy number when monocytes were challenged with lipopolysaccharide (LPS). Consequently, production of malondialdehyde (MDA) was increased, which could increase the activation of prooxidative stress enzymes. Meanwhile, activation of an antioxidative enzyme, glutathione peroxidase (GSH-Px), was increased. Real-time PCR showed that expression of activating protein-1 (AP-1) and the antioxidative-related genes was increased. By contrast, the expression levels of superoxide dismutase 1 (SOD1) and catalase (CAT) were reduced. In transgenic sheep, glutathione (GSH) levels were dramatically reduced. Furthermore, transgenic sheep were intradermally injected with LPS in each ear. The amounts of inflammatory infiltrates were correlated with the number of TLR4 copies that were integrated in the genome. Additionally, the translation ofγ-glutamylcysteine synthetase (γ-GCS) was increased. Our findings indicated that overexpression of TLR4 in sheep could ameliorate oxidative injury through GSH secretion that was induced by LPS stimulation. Furthermore, TLR4 promotedγ-GCS translation through the AP-1 pathway, which was essential for GSH synthesis.

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