Displaying publications 1 - 20 of 21 in total

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  1. Arshad NF, Nordin FJ, Foong LC, In LLA, Teo MYM
    PLoS One, 2024;19(8):e0306111.
    PMID: 39146295 DOI: 10.1371/journal.pone.0306111
    The inability of existing vaccines to cope with the mutation rate has highlighted the need for effective preventative strategies for COVID-19. Through the secretion of immunoglobulin A, mucosal delivery of vaccines can effectively stimulate mucosal immunity for better protection against SARS-CoV-2 infection. In this study, various immunoinformatic tools were used to design a multi-epitope oral vaccine against SARS-CoV-2 based on its receptor-binding domain (RBD) and heptad repeat (HR) domains. T and B lymphocyte epitopes were initially predicted from the RBD and HR domains of SARS-CoV-2, and potential antigenic, immunogenic, non-allergenic, and non-toxic epitopes were identified. Epitopes that are highly conserved and have no significant similarity to human proteome were selected. The epitopes were joined with appropriate linkers, and an adjuvant was added to enhance the vaccine efficacy. The vaccine 3D structure constructs were docked with toll-like receptor 4 (TLR-4) and TLR1-TLR2, and the binding affinity was calculated. The designed multi-epitope vaccine construct (MEVC) consisted of 33 antigenic T and B lymphocyte epitopes. The results of molecular dockings and free binding energies confirmed that the MEVC effectively binds to TLR molecules, and the complexes were stable. The results suggested that the designed MEVC is a potentially safe and effective oral vaccine against SARS-CoV-2. This in silico study presents a novel approach for creating an oral multi-epitope vaccine against the rapidly evolving SARS-CoV-2 variants. These findings offer valuable insights for developing an effective strategy to combat COVID-19. Further preclinical and clinical studies are required to confirm the efficacy of the MEVC vaccine.
    Matched MeSH terms: Toll-Like Receptor 4/metabolism
  2. Paudel YN, Angelopoulou E, Piperi C, Othman I, Aamir K, Shaikh MF
    Cells, 2020 02 07;9(2).
    PMID: 32046119 DOI: 10.3390/cells9020383
    Alzheimer's disease (AD) is a devastating neurodegenerative disorder and a leading cause of dementia, with accumulation of amyloid-beta (Aβ) and neurofibrillary tangles (NFTs) as defining pathological features. AD presents a serious global health concern with no cure to date, reflecting the complexity of its pathogenesis. Recent evidence indicates that neuroinflammation serves as the link between amyloid deposition, Tau pathology, and neurodegeneration. The high mobility group box 1 (HMGB1) protein, an initiator and activator of neuroinflammatory responses, has been involved in the pathogenesis of neurodegenerative diseases, including AD. HMGB1 is a typical damage-associated molecular pattern (DAMP) protein that exerts its biological activity mainly through binding to the receptor for advanced glycation end products (RAGE) and toll-like receptor 4 (TLR4). RAGE and TLR4 are key components of the innate immune system that both bind to HMGB1. Targeting of HMGB1, RAGE, and TLR4 in experimental AD models has demonstrated beneficial effects in halting AD progression by suppressing neuroinflammation, reducing Aβ load and production, improving spatial learning, and inhibiting microglial stimulation. Herein, we discuss the contribution of HMGB1 and its receptor signaling in neuroinflammation and AD pathogenesis, providing evidence of its beneficial effects upon therapeutic targeting.
    Matched MeSH terms: Toll-Like Receptor 4/metabolism*
  3. Ilori NTO, Liew CX, Fang CM
    Mol Biol Rep, 2020 Dec;47(12):9883-9894.
    PMID: 33244664 DOI: 10.1007/s11033-020-06025-x
    This appraisal is comprised of the inflammatory studies that have been conducted on Clinacanthus nutans, Acanthus ebracteatus, and Barleria lupulina. The review aims to provide a comprehensive evaluation of the supporting and contradictory evidence on each plants' anti-inflammatory properties, whilst addressing the gaps in the current literature. The databases used to obtain relevant studies were Google Scholar, ResearchGate, PubMed and Nusearch (University of Nottingham). A total of 13 articles were selected for this review. A. ebracteatus was found to suppress neutrophil migration and weakly inhibits chronic inflammatory cytokines. Furthermore, B. lupulina and C. nutans were shown to possess very similar anti-inflammatory properties. The studies on C. nutans indicated that its anti-inflammatory effect is strongly related to the inhibition of toll-like receptor 4 (TLR4). Moreover, several phytoconstituents isolated from B. lupulina were shown to activate the anti-inflammatory Nrf2 pathway. Overall, all the studies have provided evidence to support the use of these plants as anti-inflammatory herbal remedies. However, their exact mechanism of action and the responsible phytoconstituents are yet to be established.
    Matched MeSH terms: Toll-Like Receptor 4/metabolism
  4. Sangaran PG, Ibrahim ZA, Chik Z, Mohamed Z, Ahmadiani A
    Mol Neurobiol, 2021 May;58(5):2407-2422.
    PMID: 33421016 DOI: 10.1007/s12035-020-02227-3
    Neuroinflammation, an inflammatory response within the nervous system, has been shown to be implicated in the progression of various neurodegenerative diseases. Recent in vivo studies showed that lipopolysaccharide (LPS) preconditioning provides neuroprotection by activating Toll-like receptor 4 (TLR4), one of the members for pattern recognition receptor (PRR) family that play critical role in host response to tissue injury, infection, and inflammation. Pre-exposure to low dose of LPS could confer a protective state against cellular apoptosis following subsequent stimulation with LPS at higher concentration, suggesting a role for TLR4 pre-activation in the signaling pathway of LPS-induced neuroprotection. However, the precise molecular mechanism associated with this protective effect is not well understood. In this article, we provide an overall review of the current state of our knowledge about LPS preconditioning in attenuating apoptosis mechanism and conferring neuroprotection via TLR4 signaling pathway.
    Matched MeSH terms: Toll-Like Receptor 4/metabolism*
  5. Ng WL, Marinov GK, Chin YM, Lim YY, Ea CK
    Sci Rep, 2017 09 25;7(1):12227.
    PMID: 28947785 DOI: 10.1038/s41598-017-12550-w
    Circular RNAs (circRNAs) have recently emerged as a large class of novel non-coding RNA species. However, the detailed functional significance of the vast majority of them remains to be elucidated. Most functional characterization studies targeting circRNAs have been limited to resting cells, leaving their role in dynamic cellular responses to stimuli largely unexplored. In this study, we focus on the LPS-induced cytoplasmic circRNA, mcircRasGEF1B, and combine targeted mcircRasGEF1B depletion with high-throughput transcriptomic analysis to gain insight into its function during the cellular response to LPS stimulation. We show that knockdown of mcircRasGEF1B results in altered expression of a wide array of genes. Pathway analysis revealed an overall enrichment of genes involved in cell cycle progression, mitotic division, active metabolism, and of particular interest, NF-κB, LPS signaling pathways, and macrophage activation. These findings expand the set of functionally characterized circRNAs and support the regulatory role of mcircRasGEF1B in immune response during macrophage activation and protection against microbial infections.
    Matched MeSH terms: Toll-Like Receptor 4/metabolism*
  6. Aamir K, Sethi G, Afrin MR, Hossain CF, Jusuf PR, Sarker SD, et al.
    Life Sci, 2023 Aug 15;327:121856.
    PMID: 37307966 DOI: 10.1016/j.lfs.2023.121856
    BACKGROUND: Arjunolic acid (AA) is a potent phytochemical with multiple therapeutics effects. In this study, AA is evaluated on type 2 diabetic (T2DM) rats to understand the mechanism of β-cell linkage with Toll-like receptor 4 (TLR-4) and canonical Wnt signaling. However, its role in modulating TLR-4 and canonical Wnt/β-catenin crosstalk on insulin signaling remains unclear during T2DM. Aim The current study is aimed to examine the potential role of AA on insulin signaling and TLR-4-Wnt crosstalk in the pancreas of type 2 diabetic rats.

    METHOD: Multiple methods were used to determine molecular cognizance of AA in T2DM rats, when treated with different dosage levels. Histopathological and histomorphometry analysis was conducted using masson trichrome and H&E stains. While, protein and mRNA expressions of TLR-4/Wnt and insulin signaling were assessed using automated Western blotting (jess), immunohistochemistry, and RT-PCR.

    RESULTS: Histopathological findings revealed that AA had reversed back the T2DM-induced apoptosis and necrosis caused to rats pancreas. Molecular findings exhibited prominent effects of AA in downregulating the elevated level of TLR-4, MyD88, NF-κB, p-JNK, and Wnt/β-catenin by blocking TLR-4/MyD88 and canonical Wnt signaling in diabetic pancreas, while IRS-1, PI3K, and pAkt were all upregulated by altering the NF-κB and β-catenin crosstalk during T2DM.

    CONCLUSION: Overall results, indicate that AA has potential to develop as an effective therapeutic in the treatment of T2DM associated meta-inflammation. However, future preclinical research at multiple dose level in a long-term chronic T2DM disease model is warranted to understand its clinical relevance in cardiometabolic disease.

    Matched MeSH terms: Toll-Like Receptor 4/metabolism
  7. Hasan MM, Madhavan P, Ahmad Noruddin NA, Lau WK, Ahmed QU, Arya A, et al.
    Pharm Biol, 2023 Dec;61(1):1135-1151.
    PMID: 37497554 DOI: 10.1080/13880209.2023.2230251
    CONTEXT: Arjunolic acid (AA) is a triterpenoid saponin found in Terminalia arjuna (Roxb.) Wight & Arn. (Combretaceae). It exerts cardiovascular protective effects as a phytomedicine. However, it is unclear how AA exerts the effects at the molecular level.

    OBJECTIVE: This study investigates the cardioprotective effects of arjunolic acid (AA) via MyD88-dependant TLR4 downstream signaling marker expression.

    MATERIALS AND METHODS: The MTT viability assay was used to assess the cytotoxicity of AA. LPS induced in vitro cardiovascular disease model was developed in H9C2 and C2C12 myotubes. The treatment groups were designed such as control (untreated), LPS control, positive control (LPS + pyrrolidine dithiocarbamate (PDTC)-25 µM), and treatment groups were co-treated with LPS and three concentrations of AA (50, 75, and 100 µM) for 24 h. The changes in the expression of TLR4 downstream signaling markers were evaluated through High Content Screening (HCS) and Western Blot (WB) analysis.

    RESULTS: After 24 h of co-treatment, the expression of TLR4, MyD88, MAPK, JNK, and NF-κB markers were upregulated significantly (2-6 times) in the LPS-treated groups compared to the untreated control in both HCS and WB experiments. Evidently, the HCS analysis revealed that MyD88, NF-κB, p38, and JNK were significantly downregulated in the H9C2 myotube in the AA treated groups. In HCS, the expression of NF-κB was downregulated in C2C12. Additionally, TLR4 expression was downregulated in both H9C2 and C2C12 myotubes in the WB experiment.

    DISCUSSION AND CONCLUSIONS: TLR4 marker expression in H9C2 and C2C12 myotubes was subsequently decreased by AA treatment, suggesting possible cardioprotective effects of AA.

    Matched MeSH terms: Toll-Like Receptor 4/metabolism
  8. Abdo Qaid EY, Abdullah Z, Zakaria R, Long I
    Neurol Res, 2024 Mar;46(3):261-271.
    PMID: 38122814 DOI: 10.1080/01616412.2023.2296754
    INTRODUCTION: The neuroinflammatory response was seen to impact the formation of phosphorylated tau protein in Alzheimer's disease (AD). This study aims to investigate the molecular mechanism of minocycline in reducing phosphorylated tau protein formation in the hippocampus of lipopolysaccharide (LPS)-induced rats.

    METHODS: Fifty adult male Sprague Dawley (SD) rats were randomly allocated to 1 of 5 groups: control, LPS (5 mg/kg), LPS + minocycline (25 mg/kg), LPS + minocycline (50 mg/kg) and LPS + memantine (10 mg/kg). Minocycline and memantine were administered intraperitoneally (i.p) for two weeks, and LPS was injected i.p. once on day 5. ELISA was used to determine the level of phosphorylated tau protein in SD rats' hippocampal tissue. The density and expression of Toll-like receptor-4 (TLR-4), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-кβ), tumour necrosis factor-alpha (TNF-α), and cyclooxygenase (COX)-2 were determined using Western blot and immunohistochemistry.

    RESULTS: Minocycline, like memantine, prevented LPS-induced increasein phosphorylated tau protein level suggested via reduced density and expression of TLR-4, NF-кβ, TNF-αand COX-2 proteins in rat hippocampal tissue. Interestingly, higher doses were shown to be more neuroprotective than lower doses.

    CONCLUSION: This study suggests that minocycline suppresses the neuroinflammation signalling pathway and decreased phosphorylated tau protein formation induced by LPS in a dose-dependent manner. Minocycline can be used as a preventative and therapeutic drug for neuroinflammatory diseases such as AD.

    Matched MeSH terms: Toll-Like Receptor 4/metabolism
  9. Vallance TM, Ravishankar D, Albadawi DAI, Layfield H, Sheard J, Vaiyapuri R, et al.
    Sci Rep, 2019 12 03;9(1):18258.
    PMID: 31796818 DOI: 10.1038/s41598-019-54617-w
    Platelets are small circulating blood cells that play essential roles in the maintenance of haemostasis via blood clotting. However, they also play critical roles in the regulation of innate immune responses. Inflammatory receptors, specifically Toll-like receptor (TLR)-4, have been reported to modify platelet reactivity. A plethora of studies have reported controversial functions of TLR4 in the modulation of platelet function using various chemotypes and preparations of its ligand, lipopolysaccharide (LPS). The method of preparation of LPS may explain these discrepancies however this is not fully understood. Hence, to determine the impact of LPS on platelet activation, we used ultrapure preparations of LPS from Escherichia coli (LPSEC), Salmonella minnesota (LPSSM), and Rhodobacter sphaeroides (LPSRS) and examined their actions under diverse experimental conditions in human platelets. LPSEC did not affect platelet activation markers such as inside-out signalling to integrin αIIbβ3 or P-selectin exposure upon agonist-induced activation in platelet-rich plasma or whole blood whereas LPSSM and LPSRS inhibited platelet activation under specific conditions at supraphysiological concentrations. Overall, our data demonstrate that platelet activation is not largely influenced by any of the ultrapure LPS chemotypes used in this study on their own except under certain conditions.
    Matched MeSH terms: Toll-Like Receptor 4/metabolism
  10. Marlini M, Mabuchi A, Mallard BL, Hairulhisyam N, Akashi-Takamura S, Harper JL, et al.
    Exp Physiol, 2016 12 01;101(12):1492-1505.
    PMID: 27634415 DOI: 10.1113/EP085727
    NEW FINDINGS: What is the central question of this study? The liver regenerative process is complex and involves a sequence of signalling events, but the possible involvement of structural and haemodynamic changes in vivo during this process has never been explored. What is the main finding and its importance? Normal sinusoidal blood flow and velocity are crucial for a normal regenerative response, and delays in these haemodynamic events resulted in impaired liver regeneration in lipopolysaccharide-insensitive, C3H/HeJ mice. Toll-like receptor 4 signalling is required for restoration of normal liver architecture during the liver regenerative process. Liver regeneration is delayed in mice with a defective Toll-like receptor 4 (TLR4; C3H/HeJ mice) but is normal in TLR4 knockouts (TLR4-/- ). Here, we investigated the possible involvement of structural and haemodynamic changes in vivo in the underlying mechanism. In lipopolysaccharide-sensitive (C3H/HeN and C57BL/6) and lipopolysaccharide-insensitive (C3H/HeJ and TLR4-/- ) mice, a 70% partial hepatectomy (PH) was performed under inhalational anaesthesia. At days 3 and 7 after PH, the hepatic microcirculation was interrogated using intravital microscopy. Delayed liver regeneration was confirmed in C3H/HeJ, but not in C3H/HeN, C57BL/6 (WT) or TLR4-/- mice by liver weight-to-body-weight ratio, the percentage of proliferating cell nuclear antigen (PCNA)-positive cells and mitotic index data. At day 3 after PH, sinusoidal red blood cell velocity increased by 100% in C3H/HeN mice, but by only 40% in C3H/HeJ mice. Estimated sinusoidal blood flow was significantly higher at day 7 after PH in C3H/HeN than in C3H/HeJ mice. The hepatic cord width was significantly larger in C3H/HeN than in C3H/HeJ mice at day 3 and it was significantly larger in TLR4-/- than in C57BL/6 WT mice at day 7 after PH. Hepatocyte nucleus density and functional sinusoidal density was significantly reduced at days 3 and 7 after PH in all mouse strains compared with their zero-time controls. Functional sinusoidal density was significantly lower in C3H/HeJ compared with C3H/HeN mice at day 7 after PH. The present study indicates that altered sinusoidal blood flow and velocity in C3H/HeJ mice may contribute to the observed delay in the regenerative response in these mice. In addition, restoration of normal liver architecture may be delayed in TLR4-/- mice.
    Matched MeSH terms: Toll-Like Receptor 4/metabolism
  11. Mahita J, Harini K, Rao Pichika M, Sowdhamini R
    J Biomol Struct Dyn, 2016 Jun;34(6):1345-62.
    PMID: 26264972 DOI: 10.1080/07391102.2015.1079243
    Precise functioning and fine-tuning of Toll-like receptor 4 (TLR4) signaling is a critical requirement for the smooth functioning of the innate immune system, since aberrant TLR4 activation causes excessive production of pro-inflammatory cytokines and interferons. This can result in life threatening conditions such as septic shock and other inflammatory disorders. The TRIF-related adaptor molecule (TRAM) adaptor protein is unique to the TLR4 signaling pathway and abrogation of TRAM-mediated TLR4 signaling is a promising strategy for developing therapeutics aimed at disrupting TRAM interactions with other components of the TLR4 signaling complex. The VIPER motif from the vaccinia virus-producing protein, A46 has been reported to disrupt TRAM-TLR4 interactions. We have exploited this information, in combination with homology modeling and docking approaches, to identify a potential binding site on TRAM lined by the BB loop and αC helix. Virtual screening of commercially available small molecules targeting the binding site enabled to short-list 12 small molecules to abrogate TRAM-mediated TLR4 signaling. Molecular dynamics and molecular mechanics calculations have been performed for the analysis of these receptor-ligand interactions.
    Matched MeSH terms: Toll-Like Receptor 4/metabolism
  12. Paudel YN, Angelopoulou E, Piperi C, Othman I, Shaikh MF
    Pharmacol Res, 2020 06;156:104792.
    PMID: 32278047 DOI: 10.1016/j.phrs.2020.104792
    Amyotrophic lateral sclerosis (ALS) is a devastating and rapidly progressing neurodegenerative disorder with no effective disease-modifying treatment up to date. The underlying molecular mechanisms of ALS are not yet completely understood. However, the critical role of the innate immune system and neuroinflammation in ALS pathogenesis has gained increased attention. High mobility group box 1 (HMGB1) is a typical damage-associated molecular pattern (DAMP) molecule, acting as a pro-inflammatory cytokine mainly through activation of its principal receptors, the receptor for advanced glycation end products (RAGE) and toll-like receptor 4 (TLR4) which are crucial components of the innate immune system. HMGB1 is an endogenous ligand for both RAGE and TLR4 that mediate its biological effects. Herein, on the ground of pre-clinical findings we unravel the underlying mechanisms behind the plausible contribution of HMGB1 and its receptors (RAGE and TLR4) in the ALS pathogenesis. Furthermore, we provide an account of the therapeutic outcomes associated with inhibition/blocking of HMGB1 receptor signalling in preventing motor neuron's death and delaying disease progression in ALS experimental models. There is strong evidence that HMGB1, RAGE and TLR4 signaling axes might present potential targets against ALS, opening a novel headway in ALS research that could plausibly bridge the current treatment gap.
    Matched MeSH terms: Toll-Like Receptor 4/metabolism*
  13. Ng WL, Marinov GK, Liau ES, Lam YL, Lim YY, Ea CK
    RNA Biol, 2016 09;13(9):861-71.
    PMID: 27362560 DOI: 10.1080/15476286.2016.1207036
    Circular RNAs (circRNAs) constitute a large class of RNA species formed by the back-splicing of co-linear exons, often within protein-coding transcripts. Despite much progress in the field, it remains elusive whether the majority of circRNAs are merely aberrant splicing by-products with unknown functions, or their production is spatially and temporally regulated to carry out specific biological functions. To date, the majority of circRNAs have been cataloged in resting cells. Here, we identify an LPS-inducible circRNA: mcircRasGEF1B, which is predominantly localized in cytoplasm, shows cell-type specific expression, and has a human homolog with similar properties, hcircRasGEF1B. We show that knockdown of the expression of mcircRasGEF1B reduces LPS-induced ICAM-1 expression. Additionally, we demonstrate that mcircRasGEF1B regulates the stability of mature ICAM-1 mRNAs. These findings expand the inventory of functionally characterized circRNAs with a novel RNA species that may play a critical role in fine-tuning immune responses and protecting cells against microbial infection.
    Matched MeSH terms: Toll-Like Receptor 4/metabolism*
  14. Mi Y, Chin YX, Cao WX, Chang YG, Lim PE, Xue CH, et al.
    Int J Biol Macromol, 2020 Mar 15;147:284-294.
    PMID: 31926226 DOI: 10.1016/j.ijbiomac.2020.01.072
    Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, has gradually emerged as a public health challenge worldwide. Carrageenan is a popular food additive that has been in use for decades. However, controversy exists regarding to the safety of carrageenan due to its exacerbation of colitis in experimental models. In this study, we studied the effects of vehicle and host intestinal microflora on carrageenan inflammatory properties in C57BL/6 J mice. We found that in high-fat diet model, native carrageenan in drinking water increased the disease activity index (DAI), myeloperoxidase (MPO) activity and the mRNA expression of TLR4 in colon, whereas carrageenan-supplemented diet has no visible effects. However, no signs of colitis were observed under low-fat diet regardless of the mode of vehicle used. Moreover, we discovered that carrageenan-induced colitis in high-fat diet model was robustly correlated with changes in the composition of gut microbiota, specifically Alistipes finegoldii and Bacteroides acidifaciens. Hence, we propose that the inflammatory property of carrageenan is influenced greatly by its intake form via modification of host intestinal microecology.
    Matched MeSH terms: Toll-Like Receptor 4/metabolism
  15. Abbas MA, Suppian R
    J Infect Dev Ctries, 2019 11 30;13(11):1057-1061.
    PMID: 32087079 DOI: 10.3855/jidc.11331
    INTRODUCTION: An earlier constructed recombinant BCG expressing the MSP-1C of Plasmodium falciparum, induced inflammatory responses leading to significant production of nitric oxide (NO) alongside higher expression of the enzyme inducible nitric oxide synthase (iNOS) and significant production of the regulatory cytokine, IL-10, indicating significant immunomodulatory effects of the construct. The mechanism of these responses had not been established but is thought to involve toll-like receptor 4 (TLR-4).

    METHODOLOGY: The present study was carried out to determine the role of TLR-4 on eliciting the immunomodulatory effects of recombinant BCG expressing MSP-1C of Plasmodium falciparum leading to the production of NO and IL-10, as well as the expression of iNOS. Six groups of mice (n = 6 per group) were immunised thrice, three weeks apart with intraperitoneal phosphate buffered saline T80 (PBS-T80), BCG or rBCG in the presence or absence of a TLR-4 inhibitor; TAK-242, given one hour prior to each immunisation. Peritoneal macrophages were harvested from the mice and cultured for the determination of NO, iNOS and IL-10 via Griess assay, ELISA and Western blot respectively.

    RESULTS: The results showed significant inhibition of the production of NO and IL-10 and the expression of iNOS in all groups of mice in the presence of TAK-242.

    CONCLUSIONS: These results presented evidence of the role of TLR-4/rBCG attachment mechanism in modulating the production of NO and IL-10 and the expression of iNOS in response to our rBCG-based malaria vaccine candidate expressing MSP-1C of P. falciparum.

    Matched MeSH terms: Toll-Like Receptor 4/metabolism
  16. Choy KW, Lau YS, Murugan D, Vanhoutte PM, Mustafa MR
    J. Pharmacol. Exp. Ther., 2018 03;364(3):420-432.
    PMID: 29259041 DOI: 10.1124/jpet.117.245217
    Inflammatory injury of the endothelium leads to apoptosis and endothelial dysfunction. The current study explored the effect and mechanisms of paeonol in inflammation-induced apoptosis and endothelial dysfunction induced by lipopolysaccharides (LPSs). The effects of paeonol on LPS-induced inflammatory injury were assessed by Western blotting, flow cytometry and reactive oxygen species (ROS) measurement in human umbilical vein endothelial cells (HUVECs) and C57BL/6J mice. Vascular reactivity of isolated mouse aortae was examined using wire myographs. The exposure of HUVECs to LPS increased the protein presence of Toll-like receptor 4 (TLR4), bone morphogenic protein 4 (BMP4), BMP receptor type 1A, nicotinamide adenine dinucleotide phosphate oxidase subunit 2, mitogen-activated protein kinase (MAPK), inducible nitric oxide synthase (iNOS), and cleaved caspase 3, as well as decreased it in phosphorylated endothelial nitric oxide synthase; these effects were prevented by treatment with paeonol. Similarly, cotreatment with paeonol reversed BMP4-induced apoptosis in HUVECs. Relaxation in response to the endothelium-dependent vasodilator acetylcholine were impaired in mouse aortae after exposure to LPSs; this endothelial dysfunction was reversed by cotreatment with paeonol, noggin (a BMP4 inhibitor), TAK242 (TLR4 antagonist), apocynin (an ROS scavenger), MAPK inhibitors, and AG (an iNOS inhibitor). BMP4 small interfering RNAs (siRNAs) abolished LPS-induced upregulation of BMP4 and cleaved caspase 3 protein, but not in cells treated with TLR4 siRNA and vice versa. The silencing of TLR4 and BMP4 abolished the inhibitory effects of paeonol on LPS-induced activation of cleaved caspase 3. The present results demonstrate that paeonol reduces LPS-induced endothelial dysfunction and apoptosis by inhibiting TLR4 and BMP4 signaling independently.
    Matched MeSH terms: Toll-Like Receptor 4/metabolism*
  17. Arshad L, Haque MA, Harikrishnan H, Ibrahim S, Jantan I
    Mol Biol Rep, 2024 Jul 11;51(1):789.
    PMID: 38990383 DOI: 10.1007/s11033-024-09722-z
    BACKGROUND: Syringin, a phenylpropanoid glycoside, has exhibited numerous biological properties including inhibitory activities against various immune and inflammatory disorders. In this study, syringin isolated from Tinospora crispa was evaluated for its ability to down-regulate activated nuclear factor-kappa B (NF-κB), phosphoinositide-3-kinase-Akt (PI3K-Akt) and mitogen-activated protein kinases (MAPKs) signal transducing networks in U937 macrophages activated by lipopolysaccharide.

    METHODS: The attenuating effects of syringin on the productions of prostaglandin E2 (PGE2), cyclooxygenase-2 (COX-2), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α), and the expressions of signaling molecules of the signaling pathways were investigated by using ELISA, Western blot, and qRT-PCR.

    RESULTS: Syringin downregulated the NF-κB, MAPKs, and PI3K-Akt signal networks by significantly reducing PGE2 production in the macrophages via suppression of COX-2 gene and protein expression levels. It also reduced TNF-α and IL-1β secretion and their mRNA expression, suppressed phosphorylation of NF-κB (p65), IKKα/β, and IκBα, and restored ability of IκBα to degrade. Syringin dose-dependently attenuated Akt, p38 MAPKs, JNK, and ERK phosphorylation. Also, the expression of corresponding upstream signaling molecules toll-like receptor 4 (TLR4) and myeloid differentiation primary response gene 88 (MyD88) were down-regulated in response to syringin treatment.

    CONCLUSION: The suppressive effect of syringin on the inflammatory signaling molecules in MyD88-dependent pathways suggested it's potential as a drug candidate for development into an agent for treatment of various immune-mediated inflammatory disorders.

    Matched MeSH terms: Toll-Like Receptor 4/metabolism
  18. Sosroseno W, Musa M, Ravichandran M, Fikri Ibrahim M, Bird PS, Seymour GJ
    Oral Microbiol. Immunol., 2006 Jun;21(3):145-50.
    PMID: 16626370
    The aim of the present study was to determine whether or not lipopolysaccharide from Actinobacillus actinomycetemcomitans could stimulate arginase activity in a murine macrophage cell line (RAW264.7 cells).
    Matched MeSH terms: Toll-Like Receptor 4/metabolism
  19. Zulaziz N, Azhim A, Himeno N, Tanaka M, Satoh Y, Kinoshita M, et al.
    Hum. Cell, 2015 Oct;28(4):159-66.
    PMID: 25997703 DOI: 10.1007/s13577-015-0118-2
    Antibacterial photodynamic therapy (PDT) has come to attract attention as an alternative therapy for drug-resistant bacteria. Recent reports revealed that antibacterial PDT induces innate immune response and stimulates abundant cytokine secretion as a part of inflammatory responses. However, the underlying mechanism how antibacterial PDT interacts with immune cells responsible for cytokine secretion has not been well outlined. In this study, we aimed to clarify the difference in gene expression and cytokine secretion between combined culture of fibroblasts and macrophages and their independent cultures. SCRC-1008, mouse fibroblast cell line and J774, mouse macrophage-like cell line were co-cultured and PDT treatments with different parameters were carried out. After various incubation periods (1-24 h), cells and culture medium were collected, and mRNA and protein levels for cytokines were measured using real-time PCR and ELISA, respectively. Our results showed that fibroblasts and macrophages interact with each other to mediate the immune response. We propose that fibroblasts initially respond to PDT by expressing Hspa1b, which regulates the NF-κB pathway via Tlr2 and Tlr4. Activation of the NF-κB pathway then results in an enhanced secretion of pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β) and neutrophil chemoattractant MIP-2 and KC from macrophages.
    Matched MeSH terms: Toll-Like Receptor 4/metabolism
  20. Khan HU, Aamir K, Jusuf PR, Sethi G, Sisinthy SP, Ghildyal R, et al.
    Life Sci, 2021 Jan 15;265:118750.
    PMID: 33188836 DOI: 10.1016/j.lfs.2020.118750
    BACKGROUND: Lipopolysaccharide (LPS) is an endotoxin that leads to inflammation in many organs, including liver. It binds to pattern recognition receptors, that generally recognise pathogen expressed molecules to transduce signals that result in a multifaceted network of intracellular responses ending up in inflammation. Aim In this study, we used lauric acid (LA), a constituent abundantly found in coconut oil to determine its anti-inflammatory role in LPS-induced liver inflammation in Sprague Dawley (SD) rats.

    METHOD: Male SD rats were divided into five groups (n = 8), injected with LPS and thereafter treated with LA (50 and 100 mg/kg) or vehicle orally for 14 days. After fourteen days of LA treatment, all the groups were humanely killed to investigate biochemical parameters followed by pro-inflammatory cytokine markers; tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1β. Moreover, liver tissues were harvested for histopathological studies and evaluation of targeted protein expression with western blot and localisation through immunohistochemistry (IHC).

    RESULTS: The study results showed that treatment of LA 50 and 100 mg/kg for 14 days were able to reduce the elevated level of pro-inflammatory cytokines, liver inflammation, and downregulated the expression of TLR4/NF-κB mediating proteins in liver tissues.

    CONCLUSION: These findings suggest that treatment of LA has a protective role against LPS-induced liver inflammation in rats, thus, warrants further in-depth investigation through mechanistic approaches in different study models.

    Matched MeSH terms: Toll-Like Receptor 4/metabolism
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