酪氨酸激酶在TNF-α诱导类风湿关节炎成纤维样滑膜细胞MAPKs活化中的作用

目的 研究在类风湿关节炎成纤维样滑膜细胞（RA FLS）信号转导中,酪氨酸激酶在TNF－α刺激下丝裂原活化蛋白激酶（mitogen-activated protein kinases,MAPKs)活化中的作用。方法 原代培养类风湿关节炎成纤维样滑膜细胞。应用Western blot检测TNF－α短时间内引起RA FLS蛋白质酪氨酸磷酸化状态改变,及其对MAPKs家族成员活化的浓度效应和时相特点;并应用genistein,酪氨酸激酶（PTK）抑制剂观察对MAPKs活化的抑制情况。结果 TNF－α可以瞬时引起RA FLS蛋白质酪氨酸磷酸化程度增加;并在短时间内激活MAPKs通路（ERK2、JNK2、P38）。不同浓度梯度TNF－α作用显示：10IU／ml时对ERK2、JNK2即可达到峰值活化,100IU／ml时P38达到最大活化。时间上,ERK2、JNK2、P38的活化分别在TNF－α作用后5min、15min、15min最明显;genistein对TNF－α诱导的ERK2活化抑制作用显著,而对于JNK2、P38的抑制则较弱。结论 TNF－α在RA FLS信号转导中,可以瞬时导致蛋白质酪氨酸磷酸化程度增加,并同时激活MAPKs 3条通路,但是对MAPKs 3个亚家族成员的活化具有异质性;PTK在TNF－α导致ERK活化中发挥作用,对JNK、P38活化无明显影响。     

三七皂苷Rg1抑制脂多糖诱导小胶质细胞激活的机制研究

目的:探讨中药有效成分三七皂苷Rg1(Ginsenoside Rg1,Rg1)对抑制脂多糖(lipopolysaccharide,LPS)诱导的小胶质细胞株BV-2细胞激活的机制。方法:用LPS刺激BV-2细胞构建激活模型,采用四甲基偶氮唑蓝比色法(MTT)检测Rg1对BV-2细胞的活力影响,蛋白质免疫印迹(Western Blot)方法检测不同浓度Rg1(10、20和40μmol/L)对磷酸化的核因子-κB抑制蛋白-α(inhibitorκB-α,IκB-α)和反应结合蛋白(cAMP-responseelement binding protein,CREB)以及促分裂原活化蛋白激酶(mitogen-activated protein kinases,MAPKs)家族的细胞外信号调节激酶(extracellular signal-regulated kinase 1/2,ERK1/2)、c-Jun氨基端激酶(c-Jun N-terminal kinase,JNK)和p38促分裂原活化蛋白激酶(p38 mitogen-activated protein kinase,p38 MAPK)等细胞信号通路蛋白的表达及其变化规律。结果:不同浓度的Rg1明显抑制了LPS诱导的磷酸化IκB-α和CREB蛋白表达以及MAPKs通路(ERK1/2,JNK,p38 MAPK)磷酸化蛋白表达,并且对p38 MAPK表达的影响呈剂量依赖性。结论:Rg1可能通过抑制MAPKs的磷酸化来调控LPS诱导的小胶质细胞株BV-2细胞激活,发挥其神经抗炎的作用。     

IL-1β诱导类风湿性关节炎滑膜细胞MAPKs通路的活化(英文)

目的研究类风湿性关节炎(rheumatoidarthritis,RA)成纤维样滑膜细胞(fibroblast likesynoviocyte,FLS)信号转导中 ,IL 1β 介导的丝裂原活化的蛋白激酶(mitogen activated proteinkinaseMAPKs)的激活情况。方法原代培养RFFLS ;应用Westernblot检测IL 1β对于RAFLS蛋白质酪氨酸磷酸化状态的影响 ,及其对MAPKs家族成员活化的浓度效应和时相特点。结果IL 1β可以瞬时增加RAFLS蛋白质酪氨酸磷酸化的程度 ,并在短时间内激活MAPKs通路(以ERK2 ,JNK2和P38为主)。不同浓度的IL 1β对MAPKs的活化无明显差异 ,但ERK2,JNK2和P38的活化分别在IL 1β作用后5min ,15min和1min最明显。结论IL 1β在RAFLS信号转导中 ,可以瞬时导致蛋白质酪氨酸化的程度增加 ,并同时激活MAPKs3条通路 ;但MAPKs3个亚家族成员的活化具有异质性。     

狼疮肾炎PBMC高表达抗ds-DNA抗体和IL-6由MAPKERK1/2通路介导

目的：探讨有丝分裂原激活的蛋白激酶-细胞外调节激酶1/2（MAPKERK1/2）信号通路在系统性红斑狼疮合并肾炎（LN）患者外周血单个核细胞（PBMC）中自发高水平表达白细胞介素6（IL-6）和抗双链DNA抗体（抗ds-DNA抗体）中的作用。 方法： 分离培养患者PBMC，利用蛋白免疫印迹法、逆转录PCR 法和酶联免疫吸附法分别检测MAPKERK1/2磷酸化活化程度、IL-6表达和抗ds-DNA抗体水平，并与正常对照组比较。 结果： 26例LN患者与21例健康对照者比较，体外培养LN患者PBMC MAPKERK1/2信号通路呈高度活化状态，并自发表达高水平IL-6和抗ds-DNA抗体，组间有显著差异(P<0.05)。应用特异性阻断剂PD98059阻断LN患者PBMC MAPKERK1/2信号通路活化可显著抑制IL-6 和抗ds-DNA抗体的自发高表达。 结论： LN患者PBMC中MAPKERK1/2信号通路异常活化，并介导PBMC自发高水平表达IL-6 和抗ds-DNA抗体。     

脊髓星形胶质细胞通过调控Cx43-JNK通路介导吗啡耐受

目的探讨脊髓星形胶质细胞是否通过调控Cx43-JNK通路介导大鼠慢性吗啡耐受。方法采用SD成年大鼠,连续7 d鞘内注射吗啡(15μg/10μl)建立慢性吗啡镇痛耐受动物模型。采用热水甩尾法测定甩尾潜伏期以观察吗啡的镇痛效果。应用Western blot法检测脊髓Cx43、磷酸化JNK(p-JNK)、磷酸化c-Jun(p-c-Jun)和GFAP的表达;免疫组织荧光染色法检测脊髓GFAP的免疫反应性。结果在吗啡耐受形成的过程中,慢性鞘内注射吗啡引起大鼠脊髓GFAP表达逐渐增多,吗啡耐受时脊髓p-JNK、p-c-Jun和Cx43的表达明显增多;氟代柠檬酸(Fluorocitric acid,1 nmol/10μL)可以拮抗吗啡镇痛耐受,并且明显地抑制慢性吗啡所致的脊髓Cx43的上调,以及JNK及c-Jun的激活。结论脊髓Cx43-JNK通路参与星形胶质细胞介导的大鼠慢性吗啡镇痛耐受。     

依达拉奉经MAPKs通路对脂多糖激活的小胶质细胞Sirt3表达调控

目的 探究依达拉奉对LPS激活的小胶质细胞Sirt3和MAPKs通路相关蛋白的作用及其调控机制。方法 采用Western blot和免疫荧光双标染色检测LPS激活的BV2小胶质细胞中Sirt3和MAPKs通路相关蛋白ERK1/2、P38、JNK及p-ERK1/2、p-P38和p-JNK的表达;检测ERK1/2通路抑制剂处理后p-ERK1/2和Sirt3的表达。结果 LPS激活的BV细胞中Sirt3、p-ERK1/2、p-P38和p-JNK表达显著增高,依达拉奉能促进Sirt3和p-ERK1/2过表达,并降低p-P38和p-JNK表达;ERK1/2抑制后p-ERK1/2和Sirt3的蛋白表达降低。依达拉奉可促进激活的BV2细胞中Sirt3和p-ERK1/2过表达,并下调过表达的pP38和p-JNK。结论 依达拉奉可调节BV2细胞中MAPKs信号通路并促进Sirt3生成,可能经ERK/Sirt3通路发挥抗炎作用。     

ERK信号转导通路与类风湿关节炎

丝裂原活化蛋白激酶(mitogen-activated protein kinases,MAPKs)信号转导通路是细胞外信号引起细胞核内反应的重要通路,而细胞外信号调节激酶(extracellular signal-regulated kinase, ERK)通路是MAPKs家族中的重要成员,其异常活化与类风湿关节炎(rheumatoid arthritis,RA)关节破坏的病理过程密切相关.     

细胞DNA损伤应激反应中丝裂原活化蛋白激酶的信号通路

丝裂原活化蛋白激酶 (MAPKs)途径是细胞遗传毒性应激反应中主要的信号转导途径之一 ,它主要包括ERK ,JNK/SAPK ,p38等通路。各条通路都通过特异的MAPK信号级联放大反应使细胞形成应对DNA损伤的应激反应 ,从而保证细胞的正常生长和DNA复制的保真度。综述DNA损伤应激反应中的各条MAPK信号通路的激活机制     

p38MAPK参与千金藤素诱导的心肌细胞凋亡

目的: 探讨千金藤素(CEP)致Sprague-Dawley(SD)乳大鼠心肌细胞的凋亡作用及其信号途径。方法: 应用MTT法检测千金藤素对心肌细胞活性的抑制作用;利用Hoechst 33342染色及Western blotting方法检测凋亡相关信号分子caspase-3,观察CEP致心肌细胞凋亡的作用;采用Western blotting法观测 CEP对有丝分裂原活化蛋白激酶(MAPKs)家族3个主要信号分子c-Jun氨基端激酶(JNK)、细胞外信号调节激酶(ERK)、p38 MAPK磷酸化水平的影响,并利用ERK和p38 MAPK的特异性抑制剂,分别验证两种分子所介导的信号通路在CEP致心肌细胞凋亡中的作用。结果: (1)CEP能够剂量依赖和时间依赖地抑制心肌细胞的活性。(2)CEP作用于心肌细胞,出现细胞核碎裂现象和caspase-3激活。(3)CEP作用下p38 MAPK和ERK磷酸化水平显著增强,JNK的磷酸化状态未发生显著改变。(4)p38 MAPK磷酸化抑制剂SB203580显著减轻CEP对心肌细胞活性的抑制作用;ERK磷酸化抑制剂PD98059不能影响CEP对心肌细胞活性的抑制作用。结论: p38 MAPK参与CEP致心肌细胞凋亡作用。     

LPS诱导胰腺癌细胞Panc-1表达B7-H1

目的: 研究胰腺癌细胞株Panc-1在应用脂多糖(LPS)刺激前后B7-H1表达的变化,并探讨其可能的分子机制。方法: LPS刺激以及丝裂原活化蛋白激酶(MAPKs)的特异性抑制剂处理Panc-1细胞前后,应用Western blotting检测MAPKs信号通路中p38丝裂原活化蛋白激酶(p38)、细胞外信号调节蛋白激酶(ERK)和c-Jun氨基端激酶(JNK)磷酸化水平的变化,real-time PCR和Western blotting检测B7-H1 mRNA和蛋白的表达变化。结果: LPS刺激后B7-H1的表达显著上调,p38、ERK和JNK的磷酸化水平也明显上调,加入MAPKs特异性的抑制剂后,LPS诱导的p38、ERK和JNK的磷酸化被抑制,并且在p38和ERK的抑制剂处理后,B7-H1的表达也明显被抑制,而在JNK的抑制剂处理后B7-H1的表达没有显著变化。结论: LPS可以诱导胰腺癌细胞株Panc-1表达B7-H1,并且p38和ERK的活化在LPS诱导的B7-H1的表达过程中起着重要作用。     

JNK phosphorylation, induced during dengue virus infection, is important for viral infection and requires the presence of cholesterol

Infection with a broad diversity of viruses often activates host cell signaling pathways including the mitogen-activated protein kinase pathway. The present study established that dengue virus infection of human macrophages activates Jun NH(2)-terminal kinase (JNK) and the p38 MAPKs pathways. The activation was observed at early times after infection and occurs when either infectious or UV-inactivated dengue virus was used. The role of these activated kinases in dengue virus infection was evaluated using specific inhibitors. Inhibition of JNK and p38 kinases did result in a significant reduction in viral protein synthesis and in viral yield. Additionally, lipid rafts disruption induced a strong inhibition of JNK activation. These results suggest that, at early stages after dengue virus infection, MAPKs are activated and that activation of JNK and p38 is required for dengue virus infection.     

Differential activation and regulation of mitogen-activated protein kinases through the antigen receptor and CD40 in human B cells.

In human B cells, antigen receptor ligation and CD40 ligation are known to activate the extracellular-regulated kinases (ERK) and c-Jun N-terminal kinase (JNK) pathways, which in turn regulate many important B cell functions. We previously reported that antigen receptor ligation activated the ERK pathway whereas CD40 ligation activated the JNK/stress-activated protein kinase (SAPK) pathway. Here, we demonstrate that another SAPK, p38/Hog1, is activated by both antigen receptor ligation or CD40 ligation in a human B-lymphoblastoid cell line and tonsillar B cells. Wortmannin, an inhibitor of phosphatidylinositol 3-kinase, partially inhibited ERK2 and p38 activation triggered through the B cell receptor whereas activation of JNK1 and p38 through CD40 was not affected. PD98059, a specific inhibitor of mitogen-activated extracellular response kinase kinase (MEK), significantly inhibited ERK2 activation and partially inhibited p38 activation triggered by anti-IgM antibody treatment, but did not affect CD40-dependent signaling events. In addition, anti-IgM antibody-induced signaling pathways were shown to be PKC-dependent in contrast to the CD40-induced signaling pathways. Thus, the B cell receptor and CD40 recruit the ERK, JNK and p38 pathways by using different upstream effectors.     

Enhanced TLR4 reactivity following injury is mediated by increased p38 activation

Severe injury primes the innate-immune system for increased Toll-like receptor 4 (TLR4)-induced proinflammatory cytokine production by macrophages. In this study, we examined changes in TLR4 signaling pathways in splenic macrophages from burn-injured or sham mice to determine the molecular mechanism(s) responsible for the increased TLR4 responsiveness. Using flow cytometry and specific antibodies, we first looked for injury-induced changes in the expression levels of several TLR-associated signaling molecules. We found similar levels of myeloid differentiation primary-response protein 88 (MyD88) and interleukin-1 receptor-associated kinase-M (IRAK-M) and somewhat lower levels of total p38, extracellular signal-regulated kinase (ERK), and stress-activated protein kinase (SAPK)/c-jun N-terminal kinase (JNK) mitogen-activated protein kinases (MAPKs) in burn compared with sham macrophages. However, with the use of antibodies specific for the phosphorylated (activated) forms of the three MAPKs, we found that macrophages from burn mice showed a twofold increase in purified lipopolysaccharide (LPS)-stimulated p38 activation as compared with cells from sham mice on days 1 and 7 post-injury, whereas ERK and SAPK/JNK activation was increased by burn injury only on day 1. Using the specific p38 inhibitor (SB203580), we confirmed that the increase in tumor necrosis factor alpha production by LPS-stimulated burn macrophages requires p38 activation. Although we demonstrated that injury increases macrophage TLR4 mRNA expression and intracellular expression of TLR4-myeloid differentiation protein-2 (MD-2) protein, macrophage cell-surface expression of TLR4-MD-2 was not changed by burn injury. Our results suggest that the injury-induced increase in TLR4 reactivity is mediated, at least in part, by enhanced activation of the p38 signaling pathway.     

Paclitaxel causes mouse splenic lymphocytes to a state hyporesponsive to lipopolysaccharide stimulation

Multiple immune system actions have been ascribed to paclitaxel (taxol), a novel anticancer drug, including the capacity to induce macrophage antitumor cytotoxic molecule production. In the present studies, we demonstrated that paclitaxel produced a selective inhibition of lipopolysaccharide (LPS)-induced B cell proliferation. Similarly, in vitro polyclonal antibody-forming cell responses also were found to be inhibited by paclitaxel. Conversely, paclitaxel exhibited no inhibitory effects on concanavalin A (Con A)-induced T cell proliferation. To study the pathway leading to paclitaxel-induced immunosuppression, we analyzed Raf-1/ERK and JNK/p38 MAPK pathways, both of which have been reported to be involved in LPS signaling. Our results indicate that taxol treatment inhibits Raf-1 kinase activation while having no effect on ERK activation suggesting that ERK activation is distinct from upstream Raf-1 kinase in taxol-induced immunomodulation. Furthermore, paclitaxel pretreatment caused down-regulation of stress-activated MAPKs, JNK and p38 MAPK in lipopolysaccharide (LPS)-stimulated mouse splenic lymphocytes, demonstrating that spleen cells are induced to a state hyporesponsive to LPS stimulation by pre-exposing them to paclitaxel. Taken together, these results suggest that down-regulation of JNK/p38 MAP kinase may contribute to paclitaxel-induced immunosuppression in mouse splenic lymphocytes.     

Differential modulation of MAP kinases by zinc deficiency in IMR-32 cells: role of H(2)O(2)

The influence of zinc deficiency on the modulation of the mitogen-activated protein kinases (MAPKs) extracellular signal-regulated kinase (ERK1/2), p38, and c-Jun N-terminal kinase (JNK) was studied. Using human IMR-32 cells as a model of neuronal cells, the role of oxidants on MAPKs and activator protein-1 (AP-1) activation in zinc deficiency was investigated, characterizing the participation of these events in the triggering of apoptosis. Relative to controls, cells incubated in media with low zinc concentrations showed increased cell oxidants and hydrogen peroxide (H(2)O(2)) release, increased JNK and p38 activation, high nuclear AP-1-DNA binding activity, and AP-1-dependent gene expression. Catalase addition to the media prevented the increase of cellular oxidants and inhibited JNK, p38, and AP-1 activation. Low levels of ERK1/2 phosphorylation were observed in the zinc-deficient cells in association with a reduction in cell proliferation. Catalase treatment did not prevent the above events nor the increased rate of apoptosis in the zinc-deficient cells. It is first demonstrated that a decrease in cellular zinc triggers H(2)O(2)-independent, as well as H(2)O(2)-dependent effects on MAPKs. Zinc deficiency-induced increases in cellular H(2)O(2) can trigger the activation of JNK and p38, leading to AP-1 activation, events that are not involved in zinc deficiency-induced apoptosis.     

Differential activation of mitogen-activated protein kinase signalling pathways in the hippocampus of CRND8 transgenic mouse, a model of Alzheimer's disease

Transgenic Centre for Research in Neurodegenerative Diseases 8 (TgCRND8) mice expressing a double mutant form of human amyloid precursor protein represent a good model of Alzheimer's disease, and can be useful to clarify the involvement of mitogen-activated protein kinases (MAPK) dysregulation in the pathophysiology of this neurodegenerative disorder. Activation of extracellular regulated kinase (ERK) 1/2, jun kinase (JNK) and p38MAPK was studied in the hippocampus of 7-month-old TgCRND8 mice by immunohistochemistry and Western blot analysis using antibodies selective for the phosphorylated, and thus active, forms of the enzymes. We demonstrated that the three main MAPK pathways were differentially activated in cells of the hippocampus of TgCRND8 mice in comparison to wild type (Wt) littermates, p38MAPK and JNK being more activated, while ERK less activated. p38MAPK was significantly activated in microglia, astrocytes and neurons, around and distant from the plaques. JNK was highly activated in cells closely surrounding the plaques. No difference was observed in the activation of the two major bands of JNK, at a molecular weight of 46 kDa and 54 kDa. These data indicate the possible involvement of p38MAPK and JNK pathways dysregulation in the pathogenesis of Alzheimer's disease. The ERK2 isoform of the ERK pathway was less activated in the hippocampal dentate gyrus of Tg mice in basal conditions. Furthermore activation of the ERK pathway by ex vivo cholinergic stimulation with carbachol caused significantly higher activation of ERK in the hippocampus of Wt mice than in Tg mice. These findings may pose a molecular basis for the memory disruption of Alzheimer's disease, since proper functioning of the basal forebrain cholinergic neurons and of ERK2 is critical for memory formation.