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Sesquiterpene lactones from Ambrosia arborescens Mill. inhibit pro-inflammatory cytokine expression and modulate NF-κB signaling in human skin cells.
Svensson, D, Lozano, M, Almanza, GR, Nilsson, BO, Sterner, O, Villagomez, R
Phytomedicine : international journal of phytotherapy and phytopharmacology. 2018;:118-126
Abstract
BACKGROUND Ambrosia arborescens has been used in Andean traditional medicine to reduce problems associated with various inflammatory diseases and conditions, although the underlying mechanism is unknown. HYPOTHESIS/PURPOSE The sesquiterpene lactones (SLs) coronopilin and damsin, which are major secondary metabolites of A. arborescens, have anti-inflammatory activity by attenuation of IL-6 and MCP-1 expression and inhibition of NF-κB in human dermal fibroblasts (HDFa) and human keratinocytes (HaCaT). STUDY DESIGN In order to confirm a high concentration of damsin and coronopilin in the plant material, a quantitative method was developed. The effect of the pure compounds on cytokine and NF-κB expression was examined, as well as their effects on HDFa and HaCaT cell morphology and viability. METHODS Coronopilin and damsin were quantified by HPLC-DAD analysis, from EtOAc extracts of the aerial parts of A. arborescens. Cell morphology was investigated by phase-contrast microscopy and cell viability by the MTT assay. IL-6 and MCP-1 cytokine gene expression was assessed by quantitative real-time RT-PCR in LPS stimulated cells. The NF-κB pathway was studied through western blotting of the phosphorylated forms of p65 and p50/p105, as well as the non-phosphorylated IκB. Dexamethasone was used as positive control. RESULTS Dry aerial parts contained 12.3 mg/g and 13.4 mg/g of coronopilin and damsin, respectively. Treatment with either compound (1-10 µM) for 24 h attenuated LPS-induced mRNA expression of the pro-inflammatory cytokine IL-6 and the chemokine MCP-1 in HDFa cells. The down-regulation of MCP-1 mRNA induced by coronopilin and damsin was confirmed on the protein level. Damsin reduced phosphorylated p65 and p105 subunits in HDFa cells. Neither coronopilin nor damsin affected HDFa cell morphology and viability within the used concentration range (1-10 µM). Also, in HaCaT cells, treatment with damsin (1-10 µM) for 24 h inhibited the MCP-1 expression, and damsin thereby attenuated cytokine expression both in HDFa and HaCaT cells. CONCLUSION We show that coronopilin and damsin from A. arborescens inhibit pro-inflammatory IL-6 and MCP-1 expression in human skin cells via NF-κB inhibition, suggesting that they may be useful for antagonizing inflammatory conditions of the human skin.
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Functional domains of SP110 that modulate its transcriptional regulatory function and cellular translocation.
Leu, JS, Chang, SY, Mu, CY, Chen, ML, Yan, BS
Journal of biomedical science. 2018;(1):34
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Abstract
BACKGROUND SP110, an interferon-induced nuclear protein, belongs to the SP100/SP140 protein family. Very recently, we showed that SP110b, an SP110 isoform, controls host innate immunity to Mycobacterium tuberculosis infection by regulating nuclear factor-κB (NF-κB) activity. However, it remains unclear how the structure of SP110 relates to its cellular functions. In this study, we provide experimental data illustrating the protein domains that are responsible for its functions. METHODS We examined the effects of SP110 isoforms and a series of deletion mutants of SP110 on transcriptional regulation by luciferase reporter assays. We also employed confocal microscopy to determine the cellular distributions of enhanced green fluorescent protein-tagged SP110 isoforms and SP110 mutants. In addition, we performed immunoprecipitation and Western blotting analyses to identify the regions of SP110 that are responsible for protein interactions. RESULTS Using reporter assays, we first demonstrated that SP110 isoforms have different regulatory effects on NF-κB-mediated transcription, supporting the notion that SP110 isoforms may have distinct cellular functions. Analysis of deletion mutants of SP110 showed that the interaction of the N-terminal fragment (amino acids 1-276) of SP110 with p50, a subunit of NF-κB, in the cytoplasm plays a crucial role in the down-regulation of the p50-driven tumor necrosis factor-α (TNFα) promoter activity in the nucleus, while the middle and C-terminal regions of SP110 localize it to various cellular compartments. Surprisingly, a nucleolar localization signal (NoLS) that contains one monopartite nuclear localization signal (NLS) and one bipartite NLS was identified in the middle region of SP110. The identification of a cryptic NoLS in the SP110 suggests that although this protein forms nuclear speckles in the nucleoplasm, it may be directed into the nucleolus to carry out distinct functions under certain cellular conditions. CONCLUSIONS The findings from this study elucidating the multidomain structure of the SP110 not only identify functional domains of SP110 that are required for transcriptional regulation, cellular translocation, and protein interactions but also implicate that SP110 has additional functions through its unexpected activity in the nucleolus.
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Silencing LncRNA LOXL1-AS1 attenuates mesenchymal characteristics of glioblastoma via NF-κB pathway.
Wang, H, Li, L, Yin, L
Biochemical and biophysical research communications. 2018;(2):518-524
Abstract
The mesenchymal (MES) subtype of glioblastoma (GBM) suggested worse prognosis and a more malignant phenotype in comparison with their proneural (PN) counterpart. The plasticity between PN and MES transcriptome signatures provided clinical intervention with an manner. Few LncRNA, however, have been discovered to take part in the shift between subtypes. Here, we used transcriptomic data and experimental evidences to demonstrate that silencing LncRNA LOXL1-AS1 was a new regulator of NF-κB signaling pathway through repressing RELB directly, resulting in increased marker genes of PN subtype and decreased those of MES.GBM cell proliferation was functionally suppressed by LOXL1-AS1's knockdown expression,. Furthermore, RELB's rescue could reverse LOXL1-AS1's effects partially in GBM malignant behaviors. LOXL1-AS1 could clinically serve as a poor prognostic indicator for GBM patients. In conclusion, our results suggest that LOXL1-AS1 contributes to aggressive biological processes that are related with MES phenotype via NF-κB signaling, which expand our perceptions into the underlying mechanisms in LOXL1-AS1-based and subtype transition adapted medicine for GBM management.
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S-Nitrosylation in Regulation of Inflammation and Cell Damage.
Dasgupta, S, Gomez, JJ, Singh, I, Khan, M
Current drug targets. 2018;(15):1831-1838
Abstract
BACKGROUND Cell signaling through nitric oxide (NO) is a multifaceted mechanism, which regulates metabolic activities and fate in different tissues. The peroxynitrite (ONOO-) formed as reaction product of nitric oxide radical and superoxide interacts with cell membrane phospholipids and proteins causing damage. OBJECTIVE The reaction kinetics to form nitrotyrosine (ONOO-tyrosine) and/or nitrosylated cysteine (ONOO-cysteine) in protein molecules during posttranslational modification and nitration of lipids are therefore critical in determining cells' signaling mechanism for survival or apoptosis. RESULTS The nitrosylation was found to modulate GPCRs and activation of guanylate cyclase as well as regulate NF-κB activation. The recent findings have shown the neuroprotective effects of S- nitrosylation, though mechanism is unclear. CONCLUSION While keeping the background in mind, we address here the biological function of NO derivatives in medicine. We target four known compounds: SNAP, SIN- 1 chloride, SNP and GSNO to understand the effect of NO in different tissues. Here we analyze the existing findings to assess therapeutic relevance of NO-signaling during inflammation, vasodilation and tolerance.
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[Role of NF-κB in the protective effects of L-carnitine against oxidative injury in hepatocytes].
Li, J, Li, N, Dong, X, Yang, J, Luan, H
Wei sheng yan jiu = Journal of hygiene research. 2017;(4):533-537
Abstract
OBJECTIVE To investigate whether the protective effects of L-carnitine( LC) against hydrogen peroxide( H_2O_2)-induced injury in hepatocytes were related to nuclear factor-kappa B( NF-κB). METHODS CCK-8 and lactate dehydrogenase( LDH)methods were used to detect the influences of NF-κB inhibitors on the cell damage induced by H_2O_2. The effects of LC on the NF-κB expressions in H_2O_2-treated HL7702 cells were determined by Western blot. The translocation of NF-κB was observed by immunofluorescence staining. Electrophoretic mobility shift assay( EMSA) was used to evaluate NF-κB-DNA binding activities. RESULTS Compared with H_2O_2 group, NF-κB inhibitor groups showed increased cell activities and decreased LDH release( P < 0. 05, P < 0. 01). Western blot and immunofluorescence staining both demonstrated that the nucleus NF-κB expressions elevated in H_2O_2 group and LC had inhibitory effect on them( P < 0. 01). LC also inhibited H_2O_2-induced increase of NF-κB-DNA binding activity inHL7702 cells. CONCLUSION LC protects against H_2O_2-induced injury in HL7702 cells by inhibiting NF-κB activities.
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Nobiletin inhibits oxidized-LDL mediated expression of Tissue Factor in human endothelial cells through inhibition of NF-κB.
Cirillo, P, Conte, S, Cimmino, G, Pellegrino, G, Ziviello, F, Barra, G, Sasso, FC, Borgia, F, De Palma, R, Trimarco, B
Biochemical pharmacology. 2017;:26-33
Abstract
INTRODUCTION Flavonoids are nutrients usually included in human diet with several significant biological activities. Nobiletin is a flavonoid that, besides having anti-inflammatory and anti-tumoral activity, seems to exert protective effects on cardiovascular system. Several studies investigated nobiletin as a natural drug to antagonize the atherosclerotic disease. On the contrary, literature about its potential role in modulating the main acute complication of atherosclerosis, thrombosis, is still scanty. Several studies have indicated that Tissue Factor (TF) plays a pivotal role in the pathophysiology of cardiovascular thrombotic events by triggering the formation of intracoronary thrombi. Oxidized-LDL have an important role in promoting athero-thrombotic events. This study investigates whether nobiletin might exert protective cardiovascular effects by preventing the oxidized-LDL mediated expression of TF in human endothelial cells in vitro. Moreover, we have studied whether the nobiletin effects might be modulated by the inhibition of the NF-κB pathway. METHODS AND RESULTS In HUVEC, ox-LDL induced TF-mRNA transcription as demonstrated by real time PCR and expression of functionally active TF as demonstrated by Western-blot, FACS analysis and pro-coagulant activity assay. Nobiletin prevented these ox-LDL-mediated effects by exerting antioxidant effects, finally leading to inhibition of the transcription factor NF-κB. CONCLUSIONS These data suggest that nobiletin might be a potential antithrombotic agent of dietary origin. This flavonoid, through its antioxidant proprieties, might potentially exert an antithrombotic activity by inhibiting TF expression/activity in a cell population never investigated before in this context and that is normally represented in vessel wall such as endothelial cells.
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MED28 Regulates Epithelial-Mesenchymal Transition Through NFκB in Human Breast Cancer Cells.
Huang, CY, Hsieh, NT, Li, CI, Weng, YT, Liu, HS, Lee, MF
Journal of cellular physiology. 2017;(6):1337-1345
Abstract
MED28, a mammalian Mediator subunit, was found highly expressed in several types of malignancy, including breast cancer. Recently, we have identified a role of MED28 in regulating both cell growth and migration in human breast cancer cells. In epithelium-derived solid tumor, migration and invasion are preceded by the progression of epithelial-mesenchymal transition (EMT) which calls for downregulation of epithelial markers as well as upregulation of mesenchymal markers, among other features. The objective of this study was to investigate a putative role of MED28 in the progression of EMT in human breast cancer cells. In fibroblast-like MDA-MB-231 cells, suppression of MED28 attenuated the mesenchymal morphology, concomitantly with a reduction of several mesenchymal biomarkers and Snail, a transcriptional repressor of E-cadherin. The suppression effect was also accompanied by downregulation of p-NFκB/p65. However, overexpression of MED28 exhibited in an opposite manner. In epithelial MCF7 cells, administration of Adriamycin®, an experimental EMT induction system, led to a mesenchyme-like appearance correlated with increased expression of MED28, p-p65, and Snail, and a reciprocal change of epithelial and mesenchymal markers. Furthermore, suppression of MED28 attenuated the experimental EMT effect and restored the original expression status of E-cadherin and MMP9 in MCF7 cells. Our data indicate that MED28 modulates the development of EMT through NFκB in human breast cancer cells, further reinforcing the significance of MED28 in the progression of breast cancer on top of its role in cell growth and migration. J. Cell. Physiol. 232: 1337-1345, 2017. © 2016 Wiley Periodicals, Inc.
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Class I histone deacetylases regulate p53/NF-κB crosstalk in cancer cells.
Schäfer, C, Göder, A, Beyer, M, Kiweler, N, Mahendrarajah, N, Rauch, A, Nikolova, T, Stojanovic, N, Wieczorek, M, Reich, TR, et al
Cellular signalling. 2017;:218-225
Abstract
The transcription factors NF-κB and p53 as well as their crosstalk determine the fate of tumor cells upon therapeutic interventions. Replicative stress and cytokines promote signaling cascades that lead to the co-regulation of p53 and NF-κB. Consequently, nuclear p53/NF-κB signaling complexes activate NF-κB-dependent survival genes. The 18 histone deacetylases (HDACs) are epigenetic modulators that fall into four classes (I-IV). Inhibitors of histone deacetylases (HDACi) become increasingly appreciated as anti-cancer agents. Based on their effects on p53 and NF-κB, we addressed whether clinically relevant HDACi affect the NF-κB/p53 crosstalk. The chemotherapeutics hydroxyurea, etoposide, and fludarabine halt cell cycle progression, induce DNA damage, and lead to DNA fragmentation. These agents co-induce p53 and NF-κB-dependent gene expression in cell lines from breast and colon cancer and in primary chronic lymphatic leukemia (CLL) cells. Using specific HDACi, we find that the class I subgroup of HDACs, but not the class IIb deacetylase HDAC6, are required for the hydroxyurea-induced crosstalk between p53 and NF-κB. HDACi decrease the basal and stress-induced expression of p53 and block NF-κB-regulated gene expression. We further show that class I HDACi induce senescence in pancreatic cancer cells with mutant p53.
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Effect of vitamin D supplementation on inflammation and nuclear factor kappa-B activity in overweight/obese adults: a randomized placebo-controlled trial.
Mousa, A, Naderpoor, N, Johnson, J, Sourris, K, de Courten, MPJ, Wilson, K, Scragg, R, Plebanski, M, de Courten, B
Scientific reports. 2017;(1):15154
Abstract
In-vitro studies suggest that vitamin D reduces inflammation by inhibiting nuclear factor kappa-B (NFκB) activity. Yet, no trials have examined the effects of vitamin D supplementation on NFκB activity in-vivo in humans. We conducted a double-blind randomized trial (RCT) examining effects of vitamin D supplementation on inflammatory markers and NFκB activity in peripheral blood mononuclear cells (PBMCs). Sixty-five overweight/obese, vitamin D-deficient (25-hydroxyvitamin D [25(OH)D] ≤ 50 nmol/L) adults were randomized to a single 100,000 IU bolus followed by 4,000 IU daily cholecalciferol or matching placebo for 16 weeks. We measured BMI, % body fat, serum 25(OH)D, high-sensitivity C-reactive protein (hsCRP), tumour necrosis factor (TNF), monocyte chemoattractant protein-1 (MCP-1), interferon-gamma (IFN-γ), several interleukins, and NFκB activity in PBMCs. Fifty-four participants completed the study. Serum 25(OH)D concentrations increased with vitamin D supplementation compared to placebo (p < 0.001). Vitamin D and placebo groups did not differ in any inflammatory markers or NFκB activity (all p > 0.05). Results remained non-significant after adjustment for age, sex, and % body fat, and after further adjustment for sun exposure, physical activity, and dietary vitamin D intake. Although in-vitro studies report anti-inflammatory effects of vitamin D, our RCT data show no effect of vitamin D supplementation on inflammatory markers or NFκB activity in-vivo in humans.
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The Importance of Toll-like Receptors in NF-κB Signaling Pathway Activation by Helicobacter pylori Infection and the Regulators of this Response.
Hu, Y, Liu, JP, Zhu, Y, Lu, NH
Helicobacter. 2016;(5):428-40
Abstract
Helicobacter pylori (H. pylori) is a common pathogenic bacterium in the stomach that infects almost half of the population worldwide and is closely related to gastric diseases and some extragastric diseases, including iron-deficiency anemia and idiopathic thrombocytopenic purpura. Both the Maastricht IV/Florence consensus report and the Kyoto global consensus report have proposed the eradication of H. pylori to prevent gastric cancer as H.pylori has been shown to be a major cause of gastric carcinogenesis. The interactions between H. pylori and host receptors induce the release of the proinflammatory cytokines by activating proinflammatory signaling pathways such as nuclear factor kappa B (NF-κB), which plays a central role in inflammation, immune response, and carcinogenesis. Among these receptors, Toll-like receptors (TLRs) are classical pattern recognition receptors in the recognition of H. pylori and the mediation of the host inflammatory and immune responses to H. pylori. TLR polymorphisms also contribute to the clinical consequences of H. pylori infection. In this review, we focus on the functions of TLRs in the NF-κB signaling pathway activated by H. pylori, the regulators modulating this response, and the functions of TLR polymorphisms in H.pylori-related diseases.