共查询到20条相似文献,搜索用时 31 毫秒
1.
The failure of chondrocytes to replace the lost extracellular matrix contributes to the progression of degenerative disorders of cartilage. Inflammatory mediators present in the joint regulate the breakdown of the established matrix and the synthesis of new extracellular matrix molecules. In the present study, we investigated the effects of tumor necrosis factor alpha (TNF-alpha) and epidermal growth factor (EGF) on chondrocyte morphology and matrix gene expression. Chondrocytes were isolated from distal femoral condyles of neonatal rats. Cells in primary culture displayed a cobblestone appearance. EGF, but not TNF-alpha, increased the number of cells exhibiting an elongated morphology. TNF-alpha potentiated the effect of EGF on chondrocyte morphology. Individually, TNF-alpha and EGF diminished levels of aggrecan and type II collagen mRNA. In combination, the effects of TNF-alpha and EGF were additive, indicating the involvement of discrete signaling pathways. Cell viability was not compromised by TNF-alpha or by EGF, alone or in combination. EGF alone did not activate NF-kappaB or alter NF-kappaB activation by TNF-alpha. Pharmacologic studies indicated that the effects of TNF-alpha and EGF alone or in combination were independent of protein kinase C signaling, but were dependent on MEK1/2 activity. Finally, we analyzed the involvement of Sox-9 using a reporter construct of the 48 base pair minimal enhancer of type II collagen. TNF-alpha attenuated enhancer activity as expected; in contrast, EGF did not alter either the effect of TNF-alpha or basal activity. TNF-alpha and EGF, acting through distinct signaling pathways, thus have additive adverse effects on chondrocyte function. These findings provide critical insights into the control of chondrocytes through the integration of multiple extracellular signals. 相似文献
2.
3.
4.
Nakaizumi A Horie T Kida T Kurimoto T Sugiyama T Ikeda T Oku H 《Cellular and molecular neurobiology》2012,32(1):95-106
Modulation of enzyme activity through nitrosylation has recently been identified as a new physiological activity of nitric
oxide (NO). We hypothesized that NO enhances the TNF-α-induced death of retinal neurons through a suppression of nuclear factor-κB
(NF-κB) by nitrosylation. In this study, cells from the RGC-5 line were exposed to different concentrations (2.0, 10, and
50 ng/ml) of TNF-α, and the degree of TNF-α-induced cell death was determined by the WST-8 assay and by flow cytometric measurements
of the externalization of phosphatidylserine. The effects of etanercept, a soluble TNFR-Fc fusion protein, and S-nitroso-N-penicillamine (SNAP), an NO donor, on the toxicity were determined. Experiments were also performed to determine whether
nitric oxide synthase (NOS) was associated with the toxicity of TNF-α. The activation of NF-κB was determined by the detection
of the p65 subunit in the nuclear extracts. Our results showed that exposure of RGC-5 cells to different concentrations of
TNF-α significantly decreased the number of living cells in a dose-dependent way. The death was partially due to apoptosis
with an externalization of phosphatidylserine, and the death was suppressed by etanercept. Exposure to TNF-α increased the
activation of NF-κB and the expression of iNOS. Although NF-κB inhibitors suppressed the increase of iNOS, they also potentiated
the TNF-α-induced death. Both L-NAME and aminoguanidine, both NOS inhibitors, rescued the cells from death. In contrast, addition
of SNAP caused nitrosylation of the inhibitory κB kinase, and suppressed the NF-κB activation and potentiated the TNF-α-induced
neurotoxicity. These results indicate that NO potentiates the neurotoxicity of TNF-α by suppressing NF-κB. 相似文献
5.
The present study attempts to investigate the effects of S-propargyl-cysteine (SPRC), a sulfur-containing amino acid, on lipopolysaccharide (LPS)-induced inflammatory response in H9c2
cardiac myocytes. We found that SPRC prevented nuclear factor-κB (NF-κB) activation assessed by NF-κB p65 phosphorylation
and IκBα degradation, suppressed LPS-induced extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation and intracellular
reactive oxygen species (ROS) production. Furthermore, incubation of H9c2 cells with SPRC induced phosphorylation of Akt in
a time- and concentration-dependent manner. In addition, SPRC attenuated LPS-induced mRNA and protein expression of tumor
necrosis factor-α (TNF-α), and mRNA expression of intercellular adhesion molecule-1 (ICAM-1) and inducible nitric oxide synthase
(iNOS). The effects of SPRC were abolished by cystathionine γ-lyase [CSE-an enzyme that synthesizes hydrogen sulfide (H2S)] inhibitor, dl-propargylglycine (PAG), SPRC-induced Akt phosphorylation and TNF-α release was also abolished by the phosphoinositide 3-kinase
(PI3K) inhibitor LY294002. Furthermore, SPRC also increased LPS-induced down-regulation expression of CSE and H2S level in H9c2 cells. PAG abolished SPRC-induced up-regulation of H2S level. Therefore, we concluded that SPRC produced an anti-inflammatory effect in LPS-stimulated H9c2 cells partly through
the CSE/H2S pathway by impairing IκBα/NF-κB signaling and by activating PI3K/Akt signaling pathway. 相似文献
6.
7.
8.
Jung Ha Kim Kabsun Kim Hye Mi Jin Insun Song Bang Ung Youn Junwon Lee Nacksung Kim 《Molecules and cells》2009,28(3):201-207
Silibinin is a polyphenolic flavonoid compound isolated from milk thistle (Silybum marianum), with known hepatoprotective, anticarcinogenic, and antioxidant effects. Herein, we show that silibinin inhibits receptor
activator of NF-κB ligand (RANKL)-induced osteoclastogenesis from RAW264.7 cells as well as from bone marrow-derived monocyte/macrophage
cells in a dose-dependent manner. Silibinin has no effect on the expression of RANKL or the soluble RANKL decoy receptor osteoprotegerin
(OPG) in osteoblasts. However, we demonstrate that silibinin can block the activation of NF-κB, c-Jun N-terminal kinase (JNK),
p38 mitogen-activated protein (MAP) kinase, and extracellular signal-regulated kinase (ERK) in osteoclast precursors in response
to RANKL. Furthermore, silibinin attenuates the induction of nuclear factor of activated T cells (NFAT) c1 and osteoclast-associated
receptor (OSCAR) expression during RANKL-induced osteoclastogenesis. We demonstrate that silibinin can inhibit TNF-α-induced
osteoclastogenesis as well as the expression of NFATc1 and OSCAR. Taken together, our results indicate that silibinin has
the potential to inhibit osteoclast formation by attenuating the downstream signaling cascades associated with RANKL and TNF-α. 相似文献
9.
To determine the contribution of IL-1β, tumor necrosis factor alpha (TNF-α) and IL-17 to AP-1, NF-κB and Egr-1 activation
in rheumatoid arthritis, the effect of the cytokines used alone or in combination was measured on TF expression in rheumatoid
synoviocytes. Effects on mRNA expression were measured by RT-PCR and effects on nuclear translocation were measured by immunocytochemistry.
To assess the functional consequences of cytokine induction, osteoprotegerin levels were measured in synoviocyte supernatants. 相似文献
10.
11.
Although the pericellular matrix (PCM) plays a central role in the communication between chondrocytes and extracellular matrix,
its composition is largely unknown. In this study, the PCM was investigated with a proteomic approach using chondrons, which
are enzymatically isolated constructs including the chondrocyte and its surrounding PCM. Chondrons and chondrocytes alone
were isolated from human articular cartilage. Proteins extracted from chondrons and chondrocytes were used for two-dimensional
electrophoresis. Protein spots were quantitatively compared between chondron and chondrocyte gels. Cellular proteins, which
had similar density between chondron and chondrocyte gels, did not proceed for analysis. Since chondrons only differ from
chondrocytes in association of the PCM, protein spots in the chondron gels that had higher quantity than that in the chondrocyte
gels were selected as candidates of the PCM components and processed for mass spectrometry. Among 15 identified peptides,
several were fragments of the three type VI collagen chains (α-1, α-2, and α-3). Other identified PCM proteins included triosephosphate
isomerase, transforming growth factor-β induced protein, peroxiredoxin-4, ADAM (A disintegrin and metalloproteinases) 28,
and latent-transforming growth factor beta-binding protein-2. These PCM components were verified with immunohisto(cyto)chemistry
for localization in the PCM region of articular cartilage. The abundance of type VI collagen in the PCM emphasizes its importance
to the microenvironment of chondrocytes. Several proteins were localized in the PCM of chondrocytes for the first time and
that warrants further investigation for their functions in cartilage biology. 相似文献
12.
R.D. Müller T. John B. Kohl A. Oberholzer T. Gust A. Hostmann M. Hellmuth D. LaFace B. Hutchins G. Laube R.W. Veh S.K. Tschoeke W. Ertel G. Schulze-Tanzil 《Cytokine》2008,44(3):377-385
Cartilage-specific extracellular matrix synthesis is the prerequisite for chondrocyte survival and cartilage function, but is affected by the pro-inflammatory cytokine TNF-α in arthritis. The aim of the present study was to characterize whether the immunoregulatory cytokine IL-10 might modulate cartilage matrix and cytokine expression in response to TNF-α. Primary human articular chondrocytes were treated with either recombinant IL-10, TNF-α or a combination of both (at 10 ng/mL each) or transduced with an adenoviral vector overexpressing human IL-10 and subsequently stimulated with 10 ng/ml TNF-α for 6 or 24 h. The effects of IL-10 on the cartilage-specific matrix proteins collagen type II, aggrecan, matrix-metalloproteinases (MMP)-3, -13 and pro-inflammatory cytokines were evaluated by real-time RT-PCR and immunohistochemistry. Transduced chondrocytes overexpressed high levels of IL-10 which significantly up-regulated collagen type II expression. TNF-α suppressed collagen type II and aggrecan, but increased MMP and cytokine expression in chondrocytes compared to the non-stimulated controls. The TNF-α mediated down-regulation of aggrecan expression was significantly antagonized by IL-10 overexpression, whereas the suppression of collagen type II was barely affected. The MMP-13 and IL-1β expression by TNF-α was slightly reduced by IL-10. These results suggest that IL-10 overexpression modulates some catabolic features of TNF-α in chondrocytes. 相似文献
13.
14.
15.
H2 is a therapeutic antioxidant that can reduce oxidative stress. Oxidized low-density lipoprotein, which plays roles in atherosclerosis,
may promote endothelial dysfunction by binding the cell-surface receptor LOX-1. LOX-1 expression can be upregulated by various
stimuli, including TNF-α. Thus, we aimed to examine whether the upregulation of LOX-1 by different stimuli could be blocked
by H2 in endothelial cells. H2 significantly abolished the upregulation of LOX-1 by different stimuli, including TNF-α, at the protein and mRNA levels.
The TNF-α-induced upregulation of LOX-1 was also attenuated by the NF-κB inhibitor N-acetyl-l-cysteine. H2 inhibited the TNF-α-induced activation of NF-κB and the phosphorylation of IκB-α. Furthermore, H2 inhibited the expression of LOX-1 and the activation of NF-κB in apolipoprotein E knockout mice, an animal model of atherosclerosis.
Thus, H2 probably inhibits cytokine-induced LOX-1 gene expression by suppressing NF-κB activation. 相似文献
16.
Michael Hoffmann Mathias Schmidt Winfried Wels 《Cancer immunology, immunotherapy : CII》1998,47(3):167-175
Tumor necrosis factor (TNF)-α has a broad range of biological activities, which depend heavily on cell type and physiological
condition. In a panel of human tumor cell lines we analyzed expression of the receptor tyrosine kinases EGFR, ErbB2 and ErbB3,
and the response to TNF-α. Among the cell lines tested those resistant to TNF-α were found to express high levels of either
EGFR, or ErbB2 and ErbB3. In TNF-sensitive breast and cervical carcinoma cells activation of EGFR or ErbB2 by the exogenous
growth factors EGF and heregulin β1 resulted in a significant increase in the number of cells surviving TNF-α treatment. In
contrast, inhibition of EGFR activation in TNF-resistant breast carcinoma cells by the novel antagonistic anti-EGFR antibody
14E1 sensitized the cells to the cytotoxic effects of TNF-α. A bacterially expressed fusion protein consisting of a 14E1 single-chain
(sc) Fv antibody fragment linked to human TNF-α retained TNF-α activity. This scFv(14E1)-TNF-α molecule localized specifically
to EGFR on the surface of tumor cells and activated the NF-κB pathway in co-cultured T cells, as demonstrated by electrophoretic
mobility shift assays.
Received: 6 May 1998 / Accepted: 16 July 1998 相似文献
17.
Rainer Voisard Nicola Huber Regine Baur Milorat Susa Oliver Ickrath Anton Both Wolfgang Koenig Vinzenz Hombach 《BMC molecular biology》2001,2(1):7-7
Background
Activation of nuclear factor-κB (NF-κB) is one of the key events in early atherosclerosis and restenosis. We hypothesized that tumor necrosis factor-α (TNF-α) induced and NF-κB mediated expression of intercellular adhesion molecule-1 (ICAM-1) can be inhibited by antisense RelA p65 and NF-κB1 p50 oligonucleotides (RelA p65 and NF-κB1 p50). 相似文献18.
Lui KE Panchal AS Santhanagopal A Dixon SJ Bernier SM 《Journal of cellular physiology》2002,192(1):102-112
Proton efflux from chondrocytes alters the extracellular pH and ionic composition of cartilage, and influences the synthesis and degradation of extracellular matrix. Epidermal growth factor (EGF) promotes chondrocyte proliferation during skeletal development and accumulates in the synovial fluid in rheumatoid arthritis. The purpose of this study was to investigate the effect of EGF on proton efflux from chondrocytes. When monitored using a Cytosensor microphysiometer, EGF was found to rapidly activate proton efflux from CFK2 chondrocytic cells and rat articular chondrocytes. The actions of EGF were concentration-dependent with half-maximal effects at 0.3-0.7 ng/ml. Partial desensitization and time-dependent recovery of the response were observed following repeated exposures to EGF. EGF-induced proton efflux was dependent on extracellular glucose, and inhibitors of Na(+)/H(+) exchange (NHE) markedly attenuated the initial increase in proton efflux. The response was diminished by inhibitors of phosphatidylinositol 3-kinase and phospholipase C, but not by inhibitors of MEK (MAPK/ERK kinase) or protein kinase A or C. Thus, EGF-induced proton efflux involves glucose metabolism and NHE, and is regulated by a discrete subset of EGF-activated signaling pathways. In vivo, proton efflux induced by EGF may lead to an acidic environment, enhancing turnover of cartilage matrix during development and in rheumatoid arthritis. 相似文献
19.
Gypenoside XLIX isolated from Gynostemma pentaphyllum inhibits nuclear factor-kappaB activation via a PPAR-alpha-dependent pathway 总被引:2,自引:0,他引:2
Huang TH Li Y Razmovski-Naumovski V Tran VH Li GQ Duke CC Roufogalis BD 《Journal of biomedical science》2006,13(4):535-548
Summary Nuclear factor (NF)-κB is important in the generation of inflammation. Besides regulating lipid metabolism, peroxisome proliferator-activated receptor (PPAR)-α activators also reduce NF-κB activation to terminate activation of inflammatory pathways. Gynostemma pentaphyllum (GP) has been used to treat various inflammatory diseases and hyperlipidemia. Here, we demonstrate that GP extract and one of its main components, Gypenoside XLIX (Gyp-XLIX) inhibited LPS-induced NF-κB activation in murine macrophages. Furthermore, Gyp-XLIX restored the LPS- and TNF-α-induced decrease in cytosolic I-κBα protein expression and inhibited the translocation of NF-κB(p65) to the nucleus in THP-1 monocyte and HUVEC cells. The inhibition of LPS- and TNF-α-induced NF-κB luciferase activity in macrophages was abolished by MK-886, a selective PPAR-α antagonist. GP extract and Gyp-XLIX (EC50: 10.1 μM) enhanced PPAR-α luciferase activity in HEK293 cells transfected with the tK-PPREx3-Luc reporter plasmid and expression vectors for PPAR-α. Additionally, Gyp-XLIX specifically enhanced PPAR-α mRNA and protein expression in THP-1-derived macrophage cells. The selectivity of Gyp-XLIX for PPAR-α was demonstrated by the activation of only PPAR-α in HEK293 cells transfected with expression vectors for PPAR-α, PPAR-β/δ or PPAR-γ1 plasmids and in THP-1-derived macrophage naturally expressing all three PPAR isoforms. The present study demonstrates that Gyp-XLIX, a naturally occurring gynosaponin, inhibits NF-κB activation via a PPAR-α-dependent pathway.Tom Hsun-Wei Huang and Yuhao Li contributed equally. 相似文献
20.
Fei Guo Xiang Guo An Xie Yuan Lei Lou Yang Wang 《Biological trace element research》2011,142(3):693-703
Lanthanide ions have been proven to have various biologic effects. Lanthanum with extremely active physical and chemical property
was evidenced to possess antibacterial and immune adjustment effects. In the present study, the anti-inflammatory effects
of lanthanum chloride (LaCl3) on lipopolysaccharide (LPS)-challenged mice were examined in vivo and in vitro. The results indicated that LaCl3 can greatly decrease the secretion of tumor necrosis factor alpha (TNF-α) and interleukin (IL)-1β as well as TNF-α mRNA expression
in the mice challenged with LPS. To clarify the mechanism involved, the effects of LaCl3 on the activation of nuclear factor (NF)-κB were examined both in liver and in peritoneal macrophages. The LPS-induced activation
of NF-κB was significantly blocked by LaCl3. These findings demonstrate that the inhibition of the LPS-induced inflammatory media, such as TNF-α and IL-1β, by LaCl3, is due to the inhibition of NF-κ B activation. 相似文献