p38 MAPK信号转导通路参与NO诱导兔关节软骨细胞凋亡

目的探讨p38 MAPK信号转导通路在软骨细胞凋亡中的作用。方法体外培养兔关节软骨细胞,一氧化氮(NO)供体NOC-18和p38 MAPK抑制剂SB203580作用于细胞24 h,用AnnexinV-FITC/PI流式细胞术检测软骨细胞凋亡率,W estern b lot测定p38、磷酸化p38蛋白的表达水平。结果与对照组比较,SB203580显著降低了NOC-18诱导的软骨细胞凋亡率(P<0.05);NOC-18以浓度依赖的方式促进p38 MAPK的磷酸化,而SB203580能抑制其磷酸化(P<0.05)。结论p38 MAPK通路参与了NO诱导的兔关节软骨细胞凋亡的信号转导。     

p38MAPK信号转导通路在EGF诱导食管腺癌SEG-1细胞表达u-PA中的作用

目的:探讨表皮生长因子(epidermal growth factor,EGF)对人食管腺癌SEG-1细胞尿激酶型纤溶酶原激活物(urokinase-type plasminogen activator,u-PA)mRNA和蛋白表达的影响及p38MAPK信号转导通路在其中的作用.方法:以相同浓度的EGF(100g/L)按时间梯度刺激SEG-1细胞,应用Western blot法测定各时间点总p38MAPK蛋白、磷酸化p38MAPK蛋白、u-PA蛋白表达,并应用RT-PCR方法检测各时间点u-PAmRNA表达.用p38MAPK特异抑制剂SB203580预处理细胞后,观察上述指标变化.结果:EGF可明显增强SEG-1细胞(u-PA)mRNA和蛋白的表达,并可激活p38MAPK蛋白的磷酸化,具有时间依赖性.SB203580能明显抑制EGF诱导的p38MAPK蛋白的磷酸化,用其阻断p38MAPK信号转导通路后,EGF对u-PAmRNA和蛋白表达的诱导作用受到显著抑制,并且具有剂量依赖性.结论:EGF可通过p38MAPK信号转导通路诱导SEG-1细胞表达u-PA.     

铜绿假单胞菌感染诱导U937细胞凋亡的研究

目的 探讨铜绿假单胞菌 (Pseudomonas aeruginosa,PA) 感染与人巨噬细胞系U937细胞凋亡的关系. 方法 以U937细胞作为PA感染的体外细胞模型,使细胞与细菌浓度比分别为1∶10、1∶20、1∶50及1∶100, 用荧光染色技术、Annexin V/ PI双染流式细胞仪检测细胞凋亡率. 结果 细胞与细菌比例为1∶10时即可引起部分U937细胞发生凋亡,Hoechst 染色法和Annexin-V FITC/PI 双染流式细胞仪检测细胞凋亡率分别为(11.67±1.75)%和(11.68±2.58)%,且U937 细胞凋亡百分率随PA感染剂量增加而增加. 结论 铜绿假单胞菌感染可诱导U937 细胞凋亡,且呈剂量依赖.     

p38MAPK信号通路的抑制减轻缺氧复氧环境下心肌细胞凋亡

目的研究p38丝裂原活化蛋白激酶(p38MAPK)信号通路抑制剂对缺氧复氧诱导的心肌细胞凋亡的影响。方法心肌细胞H9C2分为对照组(Con组)、缺氧复氧组(H/R组)、p38MAPK信号通路抑制剂SB203580组(SB203580组),Con组细胞正常培养,H/R组、SB203580组进行缺氧复氧处理,SB203580组细胞在缺氧前用p38MAPK信号通路抑制剂SB203580预处理24 h。噻唑蓝(MTT)检测细胞存活情况,流式细胞术检测细胞凋亡,二硝基苯肼显色法检测上清中乳酸脱氢酶(LDH)含量,用硫代巴比妥酸比色法检测细胞中丙二醛(MDA)含量,用黄嘌呤氧化法检测细胞中超氧化物歧化酶(SOD)含量,二氯二氢荧光素-乙酰乙酸酯(DCFH-DA)法检测细胞中活性氧(ROS)含量,Western blot检测细胞中p38MAPK、磷酸化p38MAPK(p-p38MAPK)、活化的含半胱氨酸的天冬氨酸蛋白水解酶3(Cleaved Caspase-3)蛋白表达。结果 H/R组、SB203580组细胞存活率低于Con组,凋亡率高于Con组,细胞中MDA、ROS含量高于Con组,培养液上清中LDH高于Con组,细胞中SOD含量低于Con组,细胞中p-p38MAPK、Cleaved Caspase-3蛋白水平高于Con组。SB203580组细胞存活率高于H/R组,凋亡率低于H/R组,细胞中MDA、ROS含量低于H/R组,培养液上清中LDH低于H/R组,细胞中SOD含量高于H/R组,细胞中p-p38MAPK、Cleaved Caspase-3蛋白水平低于H/R组。结论 p38MAPK信号通路抑制剂能够减轻缺氧复氧环境下心肌细胞凋亡和氧化损伤。     

p38MAPK-eNOS-N0信号通路在人脐静脉内皮细胞凋亡中的保护作用

目的探讨p38MAPK信号通路在胰高血糖素样肽1(GLP-1)拮抗人脐静脉内皮细胞凋亡中的作用。方法实验分为对照组、糖基化终末产物(AGE)组、GLP-1组、AGE+GLP-1组、AGE+SB203580组、AGE+GLP-1+SB203580组及AGE+GLP-1+L-NAME组,Western blot检测p-p38MAPK/p38MAPK、磷酸化内皮型一氧化氮合酶/内皮型一氧化氮合酶(p-eNOS/eNOS)蛋白表达情况,NO检测试剂盒(一步法)检测NO含量,DCFH-DA荧光探针检测细胞活性氧(ROS)含量,Annexin V/PI流式检测细胞凋亡率。结果与AGE组相比,GLP-1预处理可诱导p-p38MAPK蛋白表达下降(P=0.000);与对照组比较,GLP-1或p38 MAPK抑制剂(SB203580)预处理后,受AGE抑制的eNOS蛋白表达或诱导的ROS水平分别显著升高(P=0.004)或下降(P=0.000);GLP-1预处理后,因AGE诱导的细胞凋亡率显著降低(P=0.000),而加入L-NAME后,GLP-1的抗凋亡作用显著减弱(P=0.002);GLP-1预处理后,细胞NO含量较单纯AGE组明显升高(P=0.000),而予以L-NAME后,细胞NO含量显著降低(P=0.011)。结论GLP-1可抑制p38 MAPK信号通路的活化,拮抗AGE对血管内皮细胞的氧化损伤;上调eNOS蛋白的表达,拮抗AGE诱导的内皮细胞NO生成障碍及细胞凋亡,从而延缓糖尿病合并动脉粥样硬化的发生发展。     

硫化氢通过p38MAPK信号通路对肝纤维化大鼠肝细胞增殖、凋亡的影响

目的:探讨硫化氢(hydrogen sulfide,H2S)对肝纤维化大鼠肝细胞增殖、凋亡的调节作用以及P-p38丝裂原活化蛋白激酶(p38mitogen-activated protein kinase,p38MAPK)蛋白的表达的影响.方法:用四氯化碳诱导肝纤维化SD大鼠模型,将提取的肝纤维化大鼠肝细胞分组:对照组、H2S组(对照组基础上加H2S的供体N a H S至最适浓度)、S B组(对照组基础上加SB203580至最适浓度)、SB+H2S组(对照组基础上加Na HS、SB203580至最适浓度).M T T法检测N a H S及S B203580对肝纤维化大鼠肝细胞的增殖、增殖抑制率的影响;Annexin V-FITC/PI双染流式细胞术检测肝纤维化大鼠肝细胞凋亡率;Western blot技术检测P-p38MAPK蛋白在各组中的表达水平.结果:与对照组相比,低浓度H2S(50μmol/L)促进肝纤维化大鼠肝细胞增殖明显(P=0.000),对肝纤维化大鼠肝细胞凋亡无影响;SB203580可抑制肝纤维化大鼠肝细胞的增殖,伴随药物浓度的升高细胞存活率降低(P=0.000),并诱导肝纤维化大鼠肝细胞凋亡(P=0.000);P-p38MAPK蛋白在各组中均有表达,H2S组表达水平高于对照组(P=0.000),SB组、SB+H2S组与对照组、H2S组相比,P-p38MAPK蛋白的表达量均减少(均P=0.000).结论:低浓度H2S对肝纤维化大鼠肝细胞凋亡无诱导作用,但能通过激活p38MAPK信号转导通路促进其细胞增殖.     

p38 MAPK在阿尔茨海默病患者中的表达及作用机制

目的探讨p38丝裂原活化蛋白激酶(MAPK)在阿尔茨海默病(AD)患者中的表达及作用机制。方法收集82例AD患者及20例健康志愿者外周血,采用Western印迹检测p38 MAPK表达及激活情况;将PC12细胞随机分为正常组、模型组、SB203580组、模型组及SB203580组采用20μmol/L的β淀粉样蛋白(Aβ25~35)构建PC12细胞损伤模型。四甲基偶氮唑盐(MTT)法检测细胞活力,Annexin V-FITC/PI流式双染法检测细胞凋亡,紫外分光光度法检测细胞中天冬氨酸蛋白水解酶(Caspase)3活性,Western印迹检测B淋巴细胞瘤(Bcl)-2、Bcl-2相关X蛋白(Bax)、p53、酶切Caspase 3蛋白表达。结果 p38MAPK在AD患者及健康志愿者外周血淋巴细胞中的表达量差异无统计学意义(P>0.05);而pp38 MAPK在AD患者外周血淋巴细胞中的表达量显著高于健康志愿者(P<0.01)。与正常组比较,模型组细胞活力降低,细胞早期凋亡率、晚期凋亡率、Caspase3活性均显著提高,Bax、p53、酶切Caspase3表达量上调,Bcl-2表达量下调(均P<0.01)。与模型组比较,SB203580组细胞活力上升,细胞早期凋亡率、晚期凋亡率、Caspase 3活性均显著降低,Bax、p53、酶切Caspase 3表达量上调,Bcl-2表达量下调(均P<0.01)。结论pp38 MAPK在AD患者外周血中高表达,pp38 MAPK抑制剂SB203580能通过调控细胞凋亡相关蛋白表达抵抗Aβ25-35诱导的PC12细胞凋亡。     

金葡菌对U937细胞XIAP和cIAP1/2表达的影响

目的探讨X 相关凋亡抑制蛋白（XIAP）和cIAP1/2在金黄色葡萄球菌（简称金葡菌）诱导的人巨噬细胞系U937细胞凋亡中的作用。方法采用Western 印迹分析检测金葡菌感染不同时间后XIAP和cIAP1/2的表达水平;预先用不同浓度的Embelin（XIAP抑制剂）处理U937细胞60 min,观察金葡菌感染30 min后U937细胞的凋亡情况。结果随着感染时间的延长,XIAP和cIAP1/2的表达逐渐下降。加入XIAP的抑制剂Embelin后,U937细胞的凋亡率随着Embelin的浓度增加而逐渐升高。结论XIAP和cIAP1/2参与了金葡菌诱导的U937细胞凋亡过程。Embelin通过特异性地抑制XIAP表达增加金葡菌诱导的U937细胞凋亡率。     

p38在二硫苏糖醇与顺铂诱导食管癌Eca109细胞凋亡中的作用

将人食管癌Eca109细胞分为七组,其中三组分别加二硫苏糖醇(DTT,Ds)、顺铂(Cs)及二药联合(Ds Cs)处理细胞,另三组则先用磷酸化p38特异性抑制剂SB203580孵育,再分别加Ds、Cs及Ds Cs处理细胞,未加药组作为对照(C′).采用流式细胞仪技术检测细胞凋亡率.结果与C′比较,各组均存在明显差异(P均＜0.01); SB203580孵育细胞后,与相应组别比较,Ds 、Cs 、Ds Cs凋亡率均明显下降(P均＜0.01).证实p38 MAPK在Ds 和Cs诱导食管癌Eca109细胞凋亡中被显著激活,p38 MAPK的激活可能是多种上游凋亡信号传导必经的共同通路.     

阻断p38信号转导通路对血管平滑肌细胞增殖和凋亡的影响

目的:研究老年大鼠血管平滑肌细胞（VSMCs）增殖和凋亡与p38信号转导通路的关系,明确以p38为靶向的信号转导在VSMCs中的分子调控机制。方法: 将p38特异性抑制剂SB203580(25 μmol/L)作用于大鼠VSMCs,运用MTT比色法检测细胞增殖状态,流式细胞术检测SB203580对细胞凋亡的影响,Western blot法检测药物作用前后p38通路相关蛋白p38α、MKK3、GADD153和c-myc的表达及相关蛋白磷酸化活性。结果: SB203580可以时间、剂量依赖的方式抑制VSMCs增殖促进其凋亡。加入SB203580的VSMCs中p-p38α、GADD153和c-myc表达的水平,随作用时间的延长而下降（P<0.01）。结论: 阻断p38信号转导通路可能通过下调其下游靶基因GADD153和C-myc的表达,抑制血管平滑肌细胞增殖,促进其凋亡。     

硫化氢在p38MAPK信号通路对大鼠肝星状细胞凋亡中的作用

目的探讨硫化氢(H2S)在p38MAPK信号通路对大鼠肝星状细胞(hepatic stellate cell,HSC)凋亡中的作用及磷酸化P38、Caspase-3蛋白表达的变化。方法实验设对照组(HSC加含10%胎牛血清的DMEM培养液)、二甲基亚砜(DMSO)组(对照组基础上加DMSO,使其终浓度为0.1%)、NaHS组(对照组基础上加NaHS,使其终浓度为50μmol/L)、SB组(DMSO组基础上加SB203580,使其终浓度为75μmol/L)、SB加NaHS(SB+NaHS)组;采用Hoechst荧光染色检测细胞凋亡;Western blotting法检测磷酸化p38MAPK表达及Caspase-3蛋白表达水平。结果与对照组比较,SB组和SB+NaHS组HSC-T6的凋亡率增加(P0.05),NaHS组p38MAPK磷酸化水平及Caspase-3表达均明显增高(P0.01);与NaHS组比较,SB组和SB+NaHS组细胞凋亡率增加明显(P0.01),p38MAPK磷酸化水平表达降低(P0.01);SB+NaHS组较SB组Caspase-3蛋白表达升高(P0.05)。结论 p38MAPK及Caspase-3在H2S刺激的HSC-T6中表达增强,H2S能促使SB203580诱导的HSC-T6细胞凋亡,其作用机制可能与活化p38MAPK的磷酸化途径,进而激活Caspase-3的表达有关。     

Inhibition of p38 mitogen-activated protein kinase decreases cardiomyocyte apoptosis and improves cardiac function after myocardial ischemia and reperfusion

BACKGROUND: Activation of p38 mitogen-activated protein kinase (MAPK) plays an important role in apoptotic cell death. The role of p38 MAPK in myocardial injury caused by ischemia/reperfusion, an extreme stress to the heart, is unknown. METHODS AND RESULTS: Studies were performed with isolated, Langendorff-perfused rabbit hearts. Ischemia alone caused a moderate but transient increase in p38 MAPK activity (3.5-fold increase, P<0.05 versus basal). Ischemia followed by reperfusion further activated p38 MAPK, and the maximal level of activation (6.3-fold, P<0.01) was reached 10 minutes after reperfusion. Administration of SB 203580, a p38 MAPK inhibitor, decreased myocardial apoptosis (14.7+/-3.2% versus 30.6+/-3.5% in vehicle, P<0.01) and improved postischemic cardiac function. The cardioprotective effects of SB 203580 were closely related to its inhibition of p38 MAPK. Administering SB 203580 before ischemia and during reperfusion completely inhibited p38 MAPK activation and exerted the most cardioprotective effects. In contrast, administering SB 203580 10 minutes after reperfusion (a time point when maximal MAPK activation had already been achieved) failed to convey significant cardioprotection. Moreover, inhibition of p38 MAPK attenuated myocardial necrosis after a prolonged reperfusion. CONCLUSIONS: These results demonstrate that p38 MAPK plays a pivotal role in the signal transduction pathway mediating postischemic myocardial apoptosis and that inhibiting p38 MAPK may attenuate reperfusion injury.     

Conditional expression of mitogen-activated protein kinase phosphatase-1, MKP-1, is cytoprotective against UV-induced apoptosis

UV irradiation induces apoptosis in U937 human leukemic cells that is accompanied by the activation of both the stress-activated protein kinase (SAPK) and p38 mitogen-activated protein kinase (MAPK) signal transduction pathways. The MAPK phosphatase, MKP-1, is capable of inactivating both SAPK and p38 MAPK in vivo. To determine whether MKP-1-mediated inhibition of SAPK and/or p38 MAPK activity provided cytoprotection against UV-induced apoptosis, a U937 cell line conditionally expressing MKP-1 from the human metallothionein IIa promoter was established. Conditional expression of MKP-1 was found to abolish UV-induced SAPK and p38 MAPK activity, and inhibit UV-induced apoptosis as judged by both morphological criteria and DNA fragmentation. MKP-1 was also found to inhibit other biochemical events associated with apoptosis, including activation of caspase-3 and the proteolytic cleavage of the caspase-3 substrate, poly(ADP ribose) polymerase. These findings demonstrate that MKP-1 acts at a site upstream of caspase activation within the apoptotic program. The cytoprotective properties of MKP-1 do not appear to be mediated by its ability to inhibit p38 MAPK because the p38 MAPK specific inhibitor SB203580 had no effect on UV-induced apoptosis in U937 cells. Furthermore, by titrating the level of MKP-1 expression it was found that MKP-1 inhibited UV-induced SAPK activity, DNA fragmentation, and caspase-3 activation in a similar dose-dependent manner. The dual-specificity phosphatase, PAC1, which does not inhibit UV-induced activation of SAPK, did not provide a similar cytoprotection against UV-induced apoptosis. These results are consistent with a model whereby MKP-1 provides cytoprotection against UV-induced apoptosis by inhibiting UV-induced SAPK activity.     

软脂酸通过丝裂原活化蛋白激酶通路促进血管内皮细胞凋亡

目的探讨软脂酸(PA)诱导的血管内皮细胞凋亡中丝裂原活化蛋白激酶(MAPK)通路的作用。方法将人脐静脉内皮细胞(HUVEC)分对照组、PA组、MAPK通路干预组[分别先用p38抑制剂SB203580、氨基末端激酶(JNK)抑制剂PD98059、细胞外信号调节激酶(ERK)抑制剂SP600125干预]再分为PA+SB组、PA+PD组、PA+SP组。流式细胞仪检测细胞凋亡率;Western blot法检测caspase-3、磷酸化p38、JNK和ERK1/2表达水平;分光光度法检测caspase-3的活性。结果与对照组比较,PA组、PA+SB组、PA+PD组、PA+SP组HUVEC凋亡及caspase-3表达和活性明显增加,PA组磷酸化p38MAPK表达明显增加(P<0.05)。与PA组比较,PA+SB组HUVEC细胞凋亡率、caspase-3表达和活性明显降低(P<0.05);而PA+PD组和PA+SP组HUVEC凋亡率、caspase-3表达和活性无明显变化(P>0.05)。结论 PA通过p38MAPK通路促进内皮细胞凋亡。     

P38 MAPK inhibition enhancing ATO-induced cytotoxicity against multiple myeloma cells

The resistance to arsenic trioxide (ATO) treatment is relatively common (55–80%) in multiple myeloma patients. This study found that ATO at clinically achievable concentrations (2–7 μmol/l) activated p38 mitogen-activated protein kinase (MAPK) in both myeloma cell lines and primary myeloma cells, a finding not previously well-documented in myeloma cells. Inhibition of p38 MAPK activation by pharmacological inhibitors (SB203580) or downregulation of p38 MAPK by siRNA significantly increased the apoptosis and/or growth inhibition induced by ATO treatment in myeloma cells. Combination of ATO and p38 MAPK inhibition abolished the interleukin-6 enhanced protection of myeloma cells against ATO treatment. The ATO-resistant cell line developed in our laboratory showed an increase in p38 MAPK activation. The increase of apoptosis by the combination of ATO and SB203580 was accompanied by the activation of caspase-9 and caspase-8 suggesting that both extrinsic and intrinsic apoptotic pathways are involved. Additionally, the p38 MAPK activation by ATO was associated with increased phosphorylation and upregulated expression of Heat shock protein 27. These results suggest that ATO-induced p38 MAPK activation plays an important role in the resistance to ATO in myeloma cells and that p38 MAPK inhibition may overcome resistance to ATO treatment in myeloma patients.     

Lysophosphatidylcholine induces apoptosis in human endothelial cells through a p38-mitogen-activated protein kinase-dependent mechanism

Lysophosphatidylcholine (lysoPC) is a component of oxidized low density lipoprotein (LDL) and is involved in the pathogenesis of atherosclerosis and inflammation. Previous studies demonstrated that lysoPC can induce various protein kinases including tyrosine kinases, protein kinase C (PKC), and mitogen-activated protein kinases (MAPK) in vascular endothelial cells. However, the role of lysoPC-activated kinases remains undefined. In this study, we examined the effect of lysoPC on apoptosis and investigated the role of lysoPC-activated protein kinases in human umbilical vein endothelial cells (HUVEC). The presence of apoptosis was evaluated by morphological criteria, MTT assay, and electrophoresis of DNA fragments showing the characteristic apoptotic ladder, TUNEL analysis, and quantified as the proportion of hypodiploid cells by flow cytometry. The lysoPC induced apoptosis in a time- and dose-dependent manner. It stimulated the phosphorylation of extracellular signal-regulated kinase1/2 (ERK1/2) and p38-MAPK in HUVEC. The use of specific pharmacologic inhibitors indicated that the p38-MAPK-signaling pathway (SB203580) is required for lysoPC-induced apoptotic signals. Furthermore, lysoPC-induced apoptosis was inhibited by DEVD-FMK (a caspas-3/CPP32 inhibitor), suggesting involvement of an important segment in the apoptosis. These results demonstrate that lysoPC induces apoptosis in human endothelial cells through a p38-MAPK-dependent pathway.