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1.
目的:探讨培养新生大鼠皮层星形胶质细胞G蛋白偶联受体激酶5(GRK5)基因沉默后核因子κB(NF-κB)表达的变化及其与胶质细胞活化、炎症反应和氧化应激的关系。方法:采用分别或联合RNA干扰沉默GRK5基因表达与NF-κB抑制剂N-乙酰半胱氨酸干预进行实验分组。利用免疫荧光、实时定量PCR和Western blotting观察GFAP与活性caspase-3表达,细胞分泌TNF-α与NO的浓度,p65、TNF-α、IL-1β和iNOS的表达情况等。结果:GRK5 siRNA刺激星形胶质细胞活化,并检测到NF-κB表达增多(P0.01),TNF-α、IL-1β和iNOS mRNA表达水平增高(P0.01),细胞分泌TNF-α和NO增多(P0.01),活性caspase-3表达增多(P0.01)。采用GRK5 siRNA+NF-κB抑制剂联合干预可部分逆转GRK5 siRNA引起的上述变化(P0.05)。结论:GRK5基因沉默可能通过刺激NF-κB表达增多引起星形胶质细胞活化。GRK5的正常表达可能具有抑制星形胶质细胞活化相关炎症反应及氧化应激的作用。  相似文献   

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目的探讨法舒地尔(Fasudil)对脂多糖(LPS)诱导的星形胶质细胞活化和炎症反应及Toll样受体4(TLR4)/核因子κB(NF-κB)信号通路的影响。方法体外培养新生C57BL/6小鼠大脑皮质星形胶质细胞,细胞分为PBS对照组、1μg/m L LPS刺激组、1μg/m L LPS联合15μg/m L盐酸法舒地尔处理组,Griess法检测培养细胞上清液一氧化氮(NO)的水平,ELISA检测肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)、IL-10和IL-4的水平,免疫荧光细胞化学染色检测星形胶质细胞胶质原纤维酸性蛋白(GFAP)及TLR4的表达,Western blot法检测GFAP、TLR4和磷酸化的NF-κBp65(p-NF-κBp65)蛋白水平。结果与PBS组比较,LPS组NO、TNF-α和IL-6水平显著升高,IL-10和IL-4水平降低;法舒地尔能抑制LPS诱导的NO、TNF-α和IL-6的分泌,增加IL-10和IL-4的分泌。法舒地尔处理组星形胶质细胞GFAP表达显著降低,同时TLR4和NF-κB蛋白的水平也降低。结论法舒地尔阻断TLR4/NF-κB信号通路抑制LPS诱导的星形胶质细胞活化及炎性反应。  相似文献   

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目的:研究TRAIL诱导激素非依赖前列腺癌细胞株PC-3M过程中核因子kappa B(NF-κB)的活化和失活现象。方法: 当不同浓度的TRAIL和LPS作用于细胞后,我们通过细胞免疫组化染色和凝胶电泳迁移试验(EMSA)来检测NF-κB核转位的情况。并通过RT-PCR的方法粗略评定二硫代氨基甲酸吡咯烷(PDTC)对抑制蛋白IκB的影响。结果: EMSA和免疫组化分析显示PC-3M细胞中NF-κB的核转位可被TRAIL或LPS明显地激活。以PDTC预处理可以上调抑制蛋白IκB的表达,阻断NF-κB的核转位。结论: TRAIL的作用于激素非依赖前列腺癌细胞时主要的负作用在于其可以显著地刺激NF-κB的活化。另一方面,在PC-3M细胞凋亡过程中NF-κB的核转位可以被PDTC有力地抑制,同时IκB的表达升高和降解减少(PDTC引起的)是抑制NF-κB活化的潜在因素,为我们提出了增强TRAIL疗效的可能性方案。  相似文献   

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 目的: 观察染料木黄酮对人口腔癌TCA8113细胞增殖的影响,并探讨其作用机制。方法: MTT法、细胞计数法及集落形成实验检测细胞增殖;蛋白质免疫印迹检测血管内皮生长因子(VEGF)、细胞外信号调节激酶(ERK)及p-ERK的蛋白水平。结果: 染料木黄酮能显著抑制TCA8113细胞的增殖,其抗增殖活性具有浓度依赖性;染料木黄酮还可剂量依赖性地降低VEGF、ERK及p-ERK的蛋白水平;VEGF的表达可被ERK特异性抑制剂U0126所抑制;VEGF受体拮抗剂阿西替尼及U0126均显著抑制TCA8113细胞的增殖。结论: 染料木黄酮可抑制人口腔癌TCA8113细胞的增殖,其机制可能与其抑制ERK表达及活化,进而抑制VEGF的表达有关。  相似文献   

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目的:探讨表皮生长因子受体(EGFR)在肺炎克雷伯杆菌(KP)荚膜多糖(CPS)诱导人正常支气管上皮BEAS-2B细胞分泌炎性细胞因子中的作用。方法:体外培养KP并提取CPS,用不同浓度的CPS刺激BEAS-2B细胞,通过ELISA检测细胞上清中肿瘤坏死因子α(TNF-α)和白细胞介素8(IL-8)的水平,并于刺激后不同时点通过Western blot检测EGFR的磷酸化水平;EGFR抑制剂AG1478预处理BEAS-2B细胞后,Western blot检测ERK磷酸化水平,间接免疫荧光染色检测p65的核转位,并观察细胞上清中TNF-α和IL-8的变化情况;最后经ERK抑制剂PD98059和NF-κB抑制剂PDTC分别预处理后用CPS刺激细胞,ELISA检测细胞上清中TNF-α和IL-8的水平。结果:10 mg/L CPS刺激BEAS-2B细胞12 h能够显著诱导其分泌TNF-α和IL-8;Western blot和间接免疫荧光染色检测结果显示,CPS刺激可显著诱导BEAS-2B细胞中EGFR和ERK的磷酸化及p65的核转位。经EGFR抑制剂AG1478预处理细胞后,ERK的磷酸化水平...  相似文献   

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目的 研究脂多糖(LPS)对大鼠星形胶质细胞Toll样受体表达的影响及其机制。方法 在原代培养的第3代星形胶质细胞中加入不同浓度的LPS作用24h,通过免疫荧光、western blot观察星形胶质细胞 Toll样受体的表达和NF-κB p65的表达,同时研究NF-κB通路抑制剂对其的影响。结果 在正常状况下,星形胶质细胞胞浆和胞膜表达大量的TLR3受体,很少的TLR4受体。在LPS的刺激下,星形胶质细胞的TLR3表达保持不变,TLR4受体的表达随予以LPS的量增加而增高。LPS可刺激星形胶质细胞NF-κB的表达升高,抑制NF-κB通路活化抑制TLR4受体的上调。 结论 星形胶质细胞Toll样受体的表达是不同源的,TLR4受体随环境的变化而改变,其分子机制可能与NF-κB信号途径有关。  相似文献   

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目的:探讨羌活水提取物(EN)对肥大细胞活化的影响及其机制。方法:体外获取大鼠腹腔肥大细胞(RPMC),观察EN不同剂量对anti-DNP IgE诱导肥大细胞活化的影响,酶联法检测anti-DNP IgE介导的肥大细胞组胺释放,酶联免疫吸附测定法检测肥大细胞肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)释放,免疫印迹检测丝氨酸/苏氨酸蛋白激酶(Akt)、核转录因子κB(NF-κB)p65蛋白的表达。结果:体外anti-DNP IgE明显促进RPMC组胺,肿瘤坏死因子-α(TNF-α)和白介素6(IL-6)的释放,诱导Akt磷酸化和NF-κB p65活化,羌活水提取物高(200μg/L)、中(100μg/L)浓度明显抑制肥大细胞组胺,TNF-α和IL-6的释放,并抑制Akt磷酸化和NF-κB p65活化。结论:羌活水提取物通过调节Akt,NF-κB p65信号通路抑制肥大细胞介导的过敏性炎症。  相似文献   

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目的:探讨抗p185c-erbB-2/neu基因工程抗体联合紫杉醇促进p185过表达的人乳腺癌细胞系BT474凋亡的效应及其机制。方法:采用MTS法检测基因工程抗体联合紫杉醇对BT474细胞增殖的抑制作用。用AnnexinV-FITC/PI法检测BT474细胞的凋亡率;以流式细胞术(FCM)分析DNA含量及细胞周期分布;用EMSA分析NF-κB的活化水平。结果:基因工程抗体联合紫杉醇对BT474细胞增殖的抑制作用具有协同效应,并可诱导细胞凋亡,将细胞阻滞在G1期;并可显著抑制BT474细胞中NF-κB的活化。结论:紫杉醇诱导乳腺癌细胞BT474凋亡的同时,可活化NF-κB。基因工程抗体联合紫杉醇是通过抑制NF-κB的活化而增强紫杉醇诱导癌细胞凋亡的作用。  相似文献   

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目的研究氧化的低密度脂蛋白(Ox-LDL)对体外培养的人肾小球系膜细胞(HMC)核因子-κB(NF-κB)活化的影响,以及抗氧化剂吡咯二硫氨基甲酸酯(PDTC)对NF-κB活化的抑制作用,探讨Ox-LDL介导肾损害的基因调控机制及抗氧化剂PDTC防治脂质肾损害的可能性.方法将Ox-LDL或PDTC与HMC共培养后,提取细胞核蛋白进行凝胶迁移率变动分析(EMSA)检测NF-κB的活化,用细胞ELISA法检测细胞内IκBα蛋白含量的变化,反映IκBα的降解及免疫组化染色检测细胞内的P65向核转位.结果正常对照组未见NF-κB活化,当用不同浓度(10、25、50及100mg/L)的Ox-LDL,刺激肾小球系膜细胞1h后,均可引起细胞NF-κB活化及IκBα降解.与对照组相比较差异显著(p<0.05),以50 mg/L的Ox-LDL刺激HMC1h,NF-κB活化及IκBα降解最明显.NF-κB活化的同时,伴有P65由胞浆向胞核的转位.100μmol/LPDTC,能明显抑制NF-κB的活化、IκBα降解(p<0.01)及P65的核转位.结论 Ox-LDL能诱导HMC的IκBα降解、P65的核转位,最终使NF-κB活化.提示NF-κB参与了脂质肾损害的发病过程,抗氧化剂PDTC能抑制NF-κB活化.  相似文献   

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Kao SJ  Lei HC  Kuo CT  Chang MS  Chen BC  Chang YC  Chiu WT  Lin CH 《Immunology》2005,115(3):366-374
We previously demonstrated that lipoteichoic acid (LTA) might activate phosphatidylcholine-phospholipase C (PC-PLC) and phosphatidylinositol-phospholipase C (PI-PLC) to induce protein kinase C activation, which in turn initiates nuclear factor-kappaB (NF-kappaB) activation and finally induces inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) release in RAW 264.7 macrophages. In this study, we further investigated the roles of tyrosine kinase, phosphatidylinositiol 3-kinase (PI3K)/Akt, and p38 mitogen-activated protein kinase (MAPK) in LTA-induced iNOS expression and NO release in RAW 264.7 macrophages. Tyrosine kinase inhibitors (genistein and tyrphostin AG126), PI3K inhibitors (wortmannin and LY 294002), and a p38 MAPK inhibitor (SB 203580) attenuated LTA-induced iNOS expression and NO release in concentration-dependent manners. Treatment of RAW 264.7 macrophages with LTA caused time-dependent activations of Akt and p38 MAPK. The LTA-induced Akt activation was inhibited by wortmannin, LY 294002, genistein, and tyrphostin AG126. The LTA-induced p38 MAPK activation was inhibited by genistein, tyrphostin AG126, wortmannin, LY 294002, and SB 203580. The LTA-induced formation of an NF-kappaB-specific DNA-protein complex in the nucleus was inhibited by wortmannin, LY 294002, genistein, tyrphostin AG126, and SB 203580. Treatment of macrophages with LTA caused an increase in kappaB-luciferase activity, and this effect was inhibited by tyrphostin AG126, wortmannin, LY 294002, the Akt dominant negative mutant (AktDN), and SB 203580. Based on those findings, we suggest that LTA might activate the PI3K/Akt pathway through tyrosine kinase to induce p38 MAPK activation, which in turn initiates NF-kappaB activation, and ultimately induces iNOS expression and NO release in RAW 264.7 macrophages.  相似文献   

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It has been known that growth factors such as fibroblast growth factor (FGF) and platelet-derived growth factor (PDGF) can promote proliferation and migration in a variety of cell types including osteoblastic cells. However, the mechanism underlying their action has not been clearly defined. The present study was undertaken to examine the effect of FGF and PDGF on cell proliferation and migration and to determine the role of extracellular signal-regulated kinase (ERK) and Akt in action of FGF and PDGF in osteoblastic cells. FGF enhanced proliferation in a dose- and time-dependent manner, whereas it did not affect cell migration. FGF induced a transient activation of ERK, but not Akt, which was inhibited by an inhibitor of MEK, the upstream kinase of ERK, but not by inhibitors of PI3K/Akt (LY294002), epidermal growth factor receptor (EGFR, AG1478), and Src (PP2). FGF-induced proliferation was inhibited by inhibitors of MEK/ERK and Src pathways. Exposure of cells to FGF stimulated transition of cell cycle from the G1 phase to S phase and increased phosphorylation of Rb. FGF-induced phosphorylation of Rb was attenuated by inhibitors of MEK/ERK and Src pathways. Cell migration studies indicated that PDGF stimulated migration, but it had no effect on cell proliferation. PDGF induced activation of ERK and Akt. The ERK activatin was inhibited by the Src inhibitor and the Akt activation was inhibited by inhibitors of EGFR and Src. PDGF-induced migration was inhibited by inhibitors of MEK/ERK, PI3K/Akt, EGFR and Src pathways. Taken together, these findings suggest that the MEK/ERK and Src pathways play an important role in the FGF-induced proliferation and signaling pathways involving MEK/ERK, EGFR, Src and PI3K/Akt mediate the PDGF-induced migration. These data are of importance in understanding the roles of these growth factors in osteoblastic cell proliferation and migration.  相似文献   

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INTRODUCTION: Chronic activation of the angiotensin II (AngII) type 1 receptor (AT-1) is a central event in the development of chronic kidney disease (CKD), in part through enhanced expression of TGF-beta, and AT-1 receptor blockade inhibits the progression to CKD in a variety of disease states. The AT-1 receptor is a heptahelical Gaq/11-coupled receptor that initiates phospholipase C activity and release of intracellular calcium; recent data suggest that the AT-1 receptor can also activate the epidermal growth factor receptor (EGFR), although the roles of specific EGF-mediated signaling cascades in AT-1 effects on mesangial cell biology are uncertain. We hypothesized that 2 EGFR-activated pathways, PI3 kinase and MAP kinase, are stimulated by the AT-1 receptor and, in part, regulate the effects of AngII on TGF-beta1 levels in mesangial cells. METHODS: We examined the effects of AT-1 receptor activation on EGFR, PI3 kinase, and MAP kinase activation in murine mesangial cells. Upon achieving 60-80% confluence, the medium was changed to low-serum for 48 hr and cells were exposed to either the AT-1 receptor blocker, losartan, the EGFR blocker, AG1478, or control medium, and then stimulated with AngII. Similar experiments were performed using LY294002 and U0126, specific inhibitors of PI3 kinase and MEK, respectively. Total cellular protein lysates and RNA were isolated. Activation of the receptors and pathways was evaluated by immunoblotting and levels of TGF-beta mRNA were measured using real-time quantitative RT-PCR. RESULTS: AngII induced autophosphorylation of EGFR (pY1068) and activated Akt and ERK, downstream targets of PI3 kinase and MAP kinase, respectively. AngII-mediated EGFR autophosphorylation was inhibited by losartan and AG1478. AG1478 also inhibited both basal and AngII-mediated activation of Akt and ERK. Finally, AngII-mediated increase in TGF-beta mRNA was inhibited by losartan, AG1478, LY249002, and U0126. CONCLUSIONS: Stimulation of the AT-1 receptor in murine mesangial cells results in activation of the EGF receptor with subsequent signaling through PI3 kinase and MAP kinase, thereby regulating TGF-beta mRNA levels. These data suggest that AT-1 receptor signaling pathways through EGFR may serve as a therapeutic target to inhibit the development of CKD.  相似文献   

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目的:研究慢性移植物抗宿主病(GvHD)狼疮小鼠肾组织Akt信号通路蛋白在体内是否存在异常活化及泼尼松对Akt信号通路蛋白活化的调控作用。方法:肾组织Akt和磷酸化IκBα蛋白检测采用Western blot方法, NF-κB活性检测采用电泳迁移率改变实验(EMSA)。结果:注射单细胞悬液后第8周和第12周, 狼疮鼠肾组织Akt活性、磷酸化IκBα及NF-κB活性均显著高于正常对照组(P<0.05), 第16周, 狼疮鼠肾组织Akt活性、磷酸化IκBα及NF-κB活性均与正常对照组无显著差别(P>0.05);第8周和第12周时, 狼疮小鼠肾组织Akt活性与NF-κB活性均呈正相关 (分别为r=0.523和r=0.574, P<0.05)。 泼尼松对狼疮小鼠外周血抗dsDNA抗体滴度和尿蛋白具有显著的抑制作用, 对肾脏病理改变有显著的改善作用, 同时, 泼尼松亦显著抑制狼疮小鼠肾组织Akt活性、磷酸化IκBα和NF-κB活性。结论:GvHD狼疮小鼠肾组织存在Akt-NF-κB信号通路异常活化, 泼尼松对该模型具有治疗作用可能与其抑制体内Akt-NF-κB信号通路异常活化有关。  相似文献   

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The diarrheagenic pathogen enteropathogenic Escherichia coli (EPEC) is responsible for significant infant mortality and morbidity, particularly in developing countries. EPEC pathogenesis relies on a type III secretion system-mediated transfer of virulence effectors into host cells. EPEC modulates host cell survival and inflammation, although the proximal signaling pathways have not been well defined. We therefore examined the effect of EPEC on the epidermal growth factor receptor (EGFR), a known upstream activator of both the prosurvival phosphoinositide 3-kinase/Akt and proinflammatory mitogen-activated protein (MAP) kinase pathways. EPEC induced the autophosphorylation of EGFR in intestinal epithelial cells within 15 min postinfection, with maximal phosphorylation being observed at 4 h. Filter-sterilized supernatants of EPEC cultures also stimulated EGFR phosphorylation, suggesting that a secreted component(s) contributes to this activity. EPEC-induced EGFR phosphorylation was blocked by the pharmacological inhibitor tyrphostin AG1478, as well as by EGFR-neutralizing antibodies. Inhibition of EGFR phosphorylation by AG1478 had no effect on bacterial adherence, actin recruitment to sites of attachment, or EPEC-induced epithelial barrier function alteration. EPEC-mediated Akt phosphorylation, however, was inhibited by both AG1478 and EGFR-neutralizing antibodies. Correspondingly, inhibition of EGFR activation increased the apoptosis/necrosis of infected epithelial cells. Inhibition of EGFR phosphorylation also curtailed EPEC-induced ERK1/2 (MAP kinase) phosphorylation and, correspondingly, the production of the proinflammatory cytokine interleukin-8 by infected epithelial cells. Our studies suggest that EGFR is a key proximal signaling molecule during EPEC pathogenesis.  相似文献   

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目的: 观察促性腺激素释放激素类似物(GnRHa)处理后青春期大鼠生长板体外培养的软骨细胞内是否存在生长激素(GH)与表皮生长因子受体(EGFR)之间的信号交联(cross-talk)。方法: 3周龄雌性SD大鼠开始注射GnRHa至7周龄;随后分离培养5-8只大鼠胫骨生长板软骨细胞,在GH作用前分别加入JAK2阻断剂AG490(1 nmol/L、10 nmol/L和100 nmol/L)、EGFR酪氨酸激酶阻断剂AG1478(0.1 nmol/L、1 nmol/L和10 nmol/L)和表皮生长因子(EGF)中和抗体(0.1 mg/L、1 mg/L和10 mg/L);采用四氮甲基唑蓝(MTT)以及免疫组化法测定增殖细胞核抗原(PCNA),观察不同阻断剂对软骨细胞增殖的影响;采用Western blotting检测软骨细胞p-ERK1/2及p-EGFR的表达。结果: GH作用后具有浓度依赖性地促进软骨细胞增殖和增加p-ERK1/2及p-EGFR水平的作用,100 μg/L时作用最为明显。AG490及AG1478几乎能完全抑制GH促进软骨细胞增殖和激活ERK1/2及EGFR的作用。 而EGF中和抗体仅能部分抑制GH的作用。结论: GH通过激活JAK2而激活其下游的ERK通路,实现其直接促细胞增殖效应。GH亦能通过激活EGFR及其信号转导通路促进细胞增殖效应,表明GH通路和EGF通路间存在相互作用。  相似文献   

18.
The relaxin receptor has so far avoided molecular cloning and characterization. We have therefore characterized the signalling events activated by relaxin (RLX), using two different cell culture-based bioassay systems: primary human endometrial stromal cells from the cycle (ESC) and the human monocyte cell line THP-1. Upon RLX stimulation, both cell types showed a rapid increase in cAMP accumulation, which could be inhibited by an inhibitor of G-protein activation, GDP-beta-S. However, evolutionarily one would expect the RLX receptor, like those for the structurally related hormones insulin and insulin-like growth factor-I, to involve tyrosine kinase activity. The specific tyrphostins AG 1478, AG 527 and AG 879 inhibited the RLX-stimulated cAMP response in human ESC and THP-1 cells in a dose-dependent manner, though the potent broad range tyrphostin AG 213 had no effect. Also, treatment of THP-1 cells with the potent phosphotyrosine phosphatase inhibitors bpV(phen) and mpV(pic) increased RLX-stimulated cAMP accumulation in a dose-dependent manner. The effect of the general tyrosine kinase inhibitor genistein (which can also inhibit some phosphodiesterases) on RLX-mediated cAMP accumulation strongly depended on the activity status of phosphodiesterase. In the absence of a phosphodiesterase inhibitor, genistein enhanced RLX-stimulated cAMP accumulation in both bioassays. When phosphodiesterase was inhibited by isobutylmethylxanthine, this effect was not observed. The results imply that activation of the RLX receptor uses tyrosine kinase signalling to control phosphodiesterase activity, and hence to up-regulate intracellular cAMP.  相似文献   

19.
目的: 观察树突状细胞(DCs)成熟过程中MAPKs和NF-κB信号分子表达情况,探讨尿酸刺激DCs成熟的分子机制。方法: 用尿酸体外刺激大鼠未成熟 DCs,在不同时点(0~45 min),免疫印迹方法检测p- p38、p-ERK1/2、p-JNK和NF-κB p65表达情况;以MAPKs和NF-κB信号分子抑制剂分别联合尿酸刺激DCs 48 h后,用流式细胞术检测表面分子CD83、CD86、IA/IE的表达;ELISA法测定IL-12 p70的水平。结果: (1)尿酸刺激后15 min,DCs p- p38、p-ERK1/2、p-JNK和NF-κB p65表达量明显增加,30 min时达到最大值;使用相应信号分子抑制剂后,相关蛋白表达均不能测出。(2)经p38、JNK、NF-κB p65等信号通路抑制剂预处理后,与单独尿酸刺激相比,DCs CD83、CD86、IA/IE等表面分子表达及IL-12 p70分泌水平均出现下降(P<0.05或P<0.01),ERK1/2抑制剂预处理者,则出现表达上升(P<0.05)。结论: 尿酸可以调节DCs p38、ERK1/2、JNK、 NF-κB等信号分子的活化,从而促进DCs表面分子表达及IL-12 p70分泌。这可能为尿酸能诱导DCs成熟及提高免疫功能的分子机制之一。  相似文献   

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