TNF,p38 MAPK与细胞凋亡

丝裂素活化的蛋白激酶(MAPK)是细胞内主要的信号转导系统之一.细胞运用这一系统将胞外信号传递给胞核,参与和影响细胞的多种生理病理过程.近年来发现一类新的MAPK通路--p38 MAPK信号通路,它不仅在炎症、应激反应中具有重要作用,还参与细胞的存活、分化和凋亡等过程.p38 MAPK信号通路与TNF共同参与了对细胞凋亡的调控.p38 MAPK可以上调TNF的表达,进而诱导细胞凋亡;同时TNF可以激活p38 MAPK通路,但活化后的p38 MAPK在细胞凋亡中的作用还不明确.此通路为临床治疗疾病提供了新思路.     

P38MAPK、Caspase-8在Fas—AD诱导Bel-7402细胞凋亡中的作用

目的通过P38MAPK抑制剂SB203580及caspase-8抑制剂Ac-IEFD-cho的作用,确定P38MAPK、caspase-8的相互作用关系,进一步揭示Fas—AD诱导Bel-7402细胞凋亡的信号转导机制。方法通过RT—PCR法检测培养的Bel-7402细胞中P38MAPK mRNA、caspase．8 mRNA在Fas．AD、SB203580及Ac—IEFD—cho作用下的表达情况。结果在Fas-AD诱导Bel-7402细胞凋亡中,SB203580和Ac—IEFD—cho能分别抑制p38MAPK mRNA、caspase-8 mRNA的表达。结论在Bel-7402细胞凋亡中,P38MAPK与easpase-8参与Fas—AD凋亡途径,并且在mRNA水平进行相互调节。     

P38丝裂原活化蛋白激酶在紫外线诱导角质形成细胞凋亡中的作用

目的 探讨中波紫外线(UVB)诱导角质形成细胞凋亡机制.方法 使用0、20、30、40、60、70、90 mJ/cm2 UVB辐射人角质形成细胞(HaCaT),辐射后0、1、2、3、4、6、24、48 h收集细胞和上清.流式细胞仪检测细胞周期和凋亡;ELISA检测上清液中TNF-α水平;Western blot检测P38丝裂原活化蛋白激酶(P38MAPK)和磷酸化P38丝裂原活化蛋白激酶(p-P38MAPK)的表达.结果 UVB(30 mJ/cm2)辐射后,HaCaT细胞分泌TNF-α逐渐增加,24 h达高峰;P38抑制剂SB203580完全抑制TNF-α的分泌,部分阻止了细胞凋亡;以不同剂量UVB辐射HacaT细胞,在30 mJ/cm2时p-P38 MAPK表达量最高,且辐射后即可检测到p-P38 MAPK的表达,1 h时达高峰,以后逐渐下降,而P38MAPK表达量没有明显变化.结论 紫外线可通过激活P38 MAPK途经,促进TNF-α分泌来诱导角质形成细胞凋亡.     

p38 MAPK在顺铂诱导肾小管上皮细胞凋亡中的作用

目的:探讨p38 MAPK在顺铂诱导大鼠近端肾小管上皮细胞(RPTC)凋亡中的作用。方法:首先采用Western blot实验检测0、5、10和20μmol/L顺铂处理24 h对细胞凋亡的影响,确定最佳处理剂量;而后采用20μmol/L顺铂联合50 mg/L p38 MAPK抑制剂SB203580刺激RPTC,实验分为对照组、顺铂组及顺铂+SB203580(加入SB203580处理RPTC 1 h后再给予顺铂处理24 h)。采用相差荧光显微镜观察和流式细胞术分析顺铂处理后RPTC的凋亡情况;采用Ac-DEVD-AFC试剂盒检测RPTC裂解液中的caspase活性;Western blot实验检测p38、磷酸化p38、cleaved PARP和cleaved caspase-3等的蛋白水平;pH计检测顺铂处理后RPTC外环境pH值改变。结果:20μmol/L顺铂处理RPTC 24 h,可以明显诱导细胞凋亡;顺铂处理15 min后RPTC中p38 MAPK开始磷酸化并达到高峰。顺铂处理后12.08%的RPTC呈凋亡形态,具有增强的caspase活性,并且cleaved PARP和cleaved caspase-3水平明显升高(P0.05);p38 MAPK抑制剂SB203580可抑制p38的磷酸化,降低RPTC的凋亡率和caspase活性,并减少cleaved PARP和cleaved caspase-3的蛋白水平。同时,SB203580可逆转顺铂诱导的RPTC培养基pH值的改变。结论:p38 MAPK的磷酸化在顺铂诱导的RPTC凋亡中发挥作用。顺铂诱导RPTC凋亡后,可改变细胞外酸性环境,并可被p38 MAPK抑制剂SB203580所抑制。     

PI3K/AKT途径在HGF介导肝干细胞抗凋亡调控中的作用

目的研究PI3K(磷脂酰肌醇3激酶)和MAPK(丝裂原活化蛋白激酶)途径如何参与肝干细胞的凋亡调控；探讨PI3K和MAPK信号途径在HGF介导的抗凋亡信号中的调控。方法用大鼠肝干细胞系WBF-344细胞进行实验；用流式细胞仪检测细胞及DNA凝胶电泳及流式细胞仪检测细胞凋亡；用Western blot方法检测磷酸化MAPK及PI3K蛋白的表达。结果发现TNF-α对ActD致敏的WBF-344细胞能诱导凋亡，并且这种细胞凋亡呈现剂量效应关系；HGF对ActD／TNF—α诱导Vd3F-344细胞凋亡具有保护作用，并且这种保护作用呈剂量效应关系；Western blot结果显示，在WB细胞，HGF确实能够激活ERK、p38MAPK、PI3K／AKT信号转导途径；进一步用特异的抑制剂阻断ERK及p38MAPK途径后，并不能改变HGF对TNF-α诱导凋亡的拮抗作用，而阻断PI3K／AKT途径后，HGF的抗凋亡作用被抑制。结论TNF-α能诱导ActD致敏的肝干细胞发生凋亡，而HGF则对这种细胞凋亡有明显的拮抗作用；ERK1／2和p38MAPK途径的激活并不参与HGF介导的抗凋亡作用，HGF的抗凋亡作用是通过PI3K途径转导的。     

Manumycin通过诱导细胞凋亡抑制人胰腺导管癌细胞Panc-1活性

目的：观察manumycin对人胰腺导管癌细胞Panc-1的抑制效应，并探讨其诱导细胞凋亡是否经p38MAPK介导。 方法： 用MTT法检测manumycin对Panc-1细胞的抑癌作用。用caspase-3活性检测试剂盒定量检测manumycin诱导细胞凋亡的水平及评估特异性的p38MAPK抑制剂SB203580对它的影响。 结果： 经manumycin(6 μmol/L、18 μmol/L、54 μmol/L)处理Panc-1细胞24 h,对Panc-1细胞生长具有明显的抑制作用，其抑制率分别为8.9%、21.9%和67.0%，其中后二者的细胞活性与对照组相比有显著差异(P<0.01)，呈量效关系。用药24 h的IC50为34.7 μmol/L。同时，此药物可明显增加caspase-3的活性，且这一效应可部分地被p38抑制剂SB203580阻断。 结论： Manumycin可通过诱导Panc-1细胞凋亡而产生抑癌作用，p38MAPK是manumycin诱导细胞凋亡的通路之一。     

抑制免疫抑制因子COX-2 对视网膜神经节细胞凋亡的影响及 p38MAPK 信号的调控作用

目的:探讨环氧合酶-2(COX-2)抑制剂NS-398对H_2O_2诱导的视网膜神经节RGC-5细胞活力和凋亡及p38MAPK信号通路的调控作用。方法:200、300、400、600、800μmol/L的H_2O_2刺激视网膜神经节RGC-5细胞建立H_2O_2损伤模型,根据半数抑制浓度选择H_2O_2的浓度; COX-2抑制剂NS-398处理H_2O_2诱导的RGC-5细胞7 h,SB203580作为p38MAPK信号通路抑制剂,通过MTT法及流式细胞术分别检测细胞的活力和凋亡率; Western blot检测细胞增殖核抗原(PCNA)、p53、p38丝裂原活化蛋白激酶(p38MAPK)、p-p38的蛋白表达。结果:不同浓度的H_2O_2均可抑制RGC-5细胞活力,且随H_2O_2浓度升高细胞活力降低,由于400μmol/L的H_2O_2可抑制一半的细胞活力,选择作为研究对象;与空白对照组比较,H_2O_2组细胞活力及PCNA蛋白表达均显著降低,细胞凋亡率及p53和p-p38的蛋白表达均显著升高,与H_2O_2组比较,H_2O_2+NS-398组细胞活力及PCNA蛋白表达均显著升高,细胞凋亡率及p53和p-p38的蛋白表达均显著降低(P0. 05);与H_2O_2+NS-398组比较,H_2O_2+NS-398+SB203580组细胞活力及PCNA蛋白表达均显著升高,细胞凋亡率及p53和p-p38的蛋白表达均显著降低(P0. 05)。结论:抑制免疫抑制因子COX-2表达可通过调控p38MAPK信号通路提高视网膜神经节细胞活力和抑制细胞凋亡。     

p38 MAPK在细胞内的定位及其对LPS刺激的反应

丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)转导通路调节着生长、分化、凋亡、细胞周期、应激反应等多种细胞过程.p38通路是新近鉴定的一条MAPK信号转导通路,参与了炎症、应激、细胞周期和凋亡等病理生理过程.蛋白激酶特定的细胞内定位及其在特定刺激作用下的移位是细胞信号维持特异性转导的重要机制之一.为了探讨p38信号转导的过程及其特异性机制,本研究应用激光共聚焦显微镜对p38MAPK4种不同的亚型在单核细胞、平滑肌细胞、心肌细胞和内皮细胞在静息和受到不同刺激的条件下的细胞内定位进行了观察,发现未受刺激的静止单核细胞,p38(α)蛋白激酶处于未激活状态,弥漫性地分布于细胞中;单核细胞、平滑肌细胞、心肌细胞和内皮细胞在受到LPS刺激后,p38(α)由胞浆移位到胞核;LPS刺激单核细胞15min后,p38开始出现明显的细胞核移位,于LPS刺激后45min入核量(核区荧光强度)达到峰值,之后维持于平台期.LPS诱导RAW细胞p38激酶活性呈一过性增强,在LPS刺激后2h其活性逐渐恢复到接近基础水平.LPS刺激RAW细胞p38移位入核明显滞后p38激活过程,提示p38移位后入细胞核依赖于p38磷酸化活化,p38磷酸化活化及由细胞浆移位到细胞核是一系列相继发生的连续事件.用p38-红色荧光蛋白融合表达载体在哺乳动物细胞的转染实验也证实了上述结果.     

Manumycin诱导细胞凋亡抑制乳腺癌细胞SK-BR-3活性

目的:研究manumycin对乳腺癌腹腔转移癌细胞株SK-BR-3的抑癌效应及其诱导凋亡。方法:用MTT法检测manumycin对SK-BR-3细胞的抑癌作用。免疫印迹方法检测p38 MAPK蛋白表达。用caspase-3活性检测试剂盒定量检测manumycin诱导细胞凋亡的水平及评估特异性的p38 MAPK抑制剂SB203580对凋亡的影响。结果:经6 μmol/L、18 μmol/L、54 μmol/L manumycin处理SK-BR-3细胞24 h时,其抑制率分别为(7.4±3.9)%、(21.0±4.4)%和(64.7±4.1)%,呈量效关系。其中后2者的细胞活性与对照组比有显著差异(P<0.01)。用药24 h的IC₅₀为42.5 μmol/L。同时此药物可明显增加caspase-3的活性,且这一效应可部分地被p38抑制剂SB203580阻断。免疫印迹结果显示manumycin促进p38的磷酸化。结论:manumycin可通过诱导SK-BR-3细胞凋亡而产生抑癌作用,p38 MAPK是manumycin诱导细胞凋亡的通路之一。     

Fractalkine通过激活p38MAPK信号通路调控狼疮性肾炎小鼠Treg细胞凋亡北大核心CSCD

目的:探讨趋化因子Fractalkine(FKN)对狼疮性肾炎(LN)小鼠Treg细胞凋亡的影响及机制。方法:构建LN小鼠模型,使用FKN中和抗体(Anti-FKN)、p38MAPK信号通路的抑制剂(SB203580)、p38MAPK信号通路的激活剂(U-46619)作用于正常小鼠及模型小鼠,采用免疫组化检测小鼠肾组织中FKN、磷酸化p38(p-p38)及Foxp3的蛋白表达;采用免疫磁珠法分选模型小鼠脾脏CD4^(+)CD25^(+)Treg细胞,使用腺病毒转染细胞的方式敲低FKN的表达水平,同时使用p38MAPK信号通路抑制剂(SB203580)及激活剂(U-46619)干预细胞。采用Western blot验证FKN敲低的成功转染、检测p38、p-p38、Foxp3、凋亡相关因子(Bax、Bcl-2及Cyt-c)的蛋白表达。结果:LN小鼠肾组织中的FKN及磷酸化p38MAPK的表达明显上调,低表达FKN可降低LN小鼠肾组织及Treg细胞中FKN和p-p38的表达,增加Foxp3的表达,同时增加细胞内抗凋亡因子Bcl-2蛋白的表达,而减少促凋亡因子Bax及Cyt-c蛋白的表达。p38MAPK信号通路抑制剂对上述因子的作用与低表达FKN相似,其激活剂可以逆转这些因子在LN小鼠Treg细胞中的表达。结论:FKN可能通过激活p38MAPK信号通路参与调控LN小鼠Treg细胞凋亡,为阐明LN的发病机制提供了实验依据。     

MAPK信号通路与神经系统损伤的研究进展

丝裂酶原活化蛋白激酶(Mitogen-activated protein kinase,MAPK)是生物体内重要的信号转导通路之一,主要有ERK、p38和JNK三条途径,参与调控多种细胞应答和生理病理过程。ERK和p38在神经损伤的区域迅速激活,减少神经损伤对机体带来的影响;磷酸化JNK在神经损伤部位聚集,促进神经细胞的凋亡,加重神经损伤发生的过程。MAPK信号通路与神经系统损伤的发生、修复存在着紧密的联系     

Apoptosis-induced inhibition of CD1d-mediated antigen presentation: different roles for caspases and signal transduction pathways

The stimulation of programmed cell death can either enhance or inhibit antigen presentation by classic major histocompatibility complex molecules. In the current study, we report that the induction of apoptosis by topoisomerase I inhibition or elevation of intracellular ceramide levels substantially impairs CD1d-mediated antigen presentation. In the former case, such a reduction occurred via the regulation of both the p38 mitogen-activated protein kinases and protein kinase C delta signal transduction pathways as well as the caspase cascade, whereas the latter was p38-(but not caspase)-dependent. Confocal microscopic analysis showed an altered intracellular distribution of CD1d following the inhibition topoisomerase I or by an increase in intracellular ceramide levels, that was prevented by p38 and caspase inhibitors. Thus, the induction of apoptosis in antigen presenting cells severely compromises CD1d-mediated antigen presentation by multiple mechanisms.     

Involvement of MAP kinases in apoptosis of macrophage treated with Trichomonas vaginalis

A primitive protozoan parasite Trichomonas vaginalis selectively activates the signal transduction pathways in macrophages (RAW264.7). This study evaluated the correlation of these signaling pathways and T. vaginalis-induced cell apoptosis. In macrophages infected with T. vaginalis, apoptosis was assessed on the basis of DNA fragmentation on agarose gel electrophoresis. Infection of macrophages with T. vaginalis induced tyrosine phosphorylation of several proteins. Infected cells with T. vaginalis were shown to associate with phosphorylation of the extracellular signal-regulated (ERK)1/2 kinase, p38, c-Jun N-terminal kinase (JNK) mitogen-activated protein (MAP) kinases on Western blot analysis. The present finding also demonstrated a link between the ERK1/2, JNK and p38 apoptotic pathways that was modulated by T. vaginalis infection.     

P38丝裂原活化蛋白激酶在炎症因子诱导糖尿病肾病中的作用

近年来的研究发现,丝裂原活化蛋白激酶(mitogen-activated protein kinase, MAPK)是细胞将信号从细胞膜传递到细胞核的主要通路.其中p38MAPK可通过调节转化生长因子β1、核因子-κB及血管内皮生长因子等炎症因子的表达影响糖尿病肾病的进程.研究p38MAPK及其信号转导通路机制可能为糖...     

Cell shrinkage as a signal to apoptosis in NIH 3T3 fibroblasts

Cell shrinkage is a hallmark of the apoptotic mode of programmed cell death, but it is as yet unclear whether a reduction in cell volume is a primary activation signal of apoptosis. Here we studied the effect of an acute elevation of osmolarity (NaCl or sucrose additions, final osmolarity 687 mosmol l⁻¹) on NIH 3T3 fibroblasts to identify components involved in the signal transduction from shrinkage to apoptosis. After 1.5 h the activity of caspase-3 started to increase followed after 3 h by the appearance of many apoptotic-like bodies. The caspase-3 activity increase was greatly enhanced in cells expressing a constitutively active G protein, Rac (RacV₁₂A₃ cell), indicating that Rac acts upstream to caspase-3 activation. The stress-activated protein kinase, p38, was significantly activated by phosphorylation within 30 min after induction of osmotic shrinkage, the phosphorylation being accelerated in fibroblasts overexpressing Rac. Conversely, the activation of the extracellular signal-regulated kinase (Erk1/2) was initially significantly decreased. Subsequent to activation of p38, p53 was activated through serine-15 phosphorylation, and active p53 was translocated from the cytosol to the nucleus. Inhibition of p38 in Rac cells reduced the activation of both p53 and caspase-3. After 60 min in hypertonic medium the rate constants for K⁺ and taurine efflux were increased, particular in Rac cells. We suggest the following sequence of events in the cell shrinkage-induced apoptotic response: cellular shrinkage activates Rac, with activation of p38, followed by phosphorylation and nuclear translocation of p53, resulting in permeability increases and caspase-3 activation.     

地塞米松诱导成骨细胞凋亡的蛋白激酶C途径

背景：地塞米松以增加细胞周期时间的方法提高细胞凋亡来减少成骨细胞和骨细胞的数量。蛋白激酶C是细胞内信号传导通路的一种,与细胞凋亡有关已有相关文献报道。 目的：探讨地塞米松诱导成骨细胞凋亡在蛋白激酶C细胞内信号转导途径方向的机制。 方法：取胎鼠骨髓间充质干细胞进行成骨诱导,分为塞米松模型组、佛波醇组和星型胞菌素组。地塞米松模型组加入1×10^-6 mol/L地塞米松,佛波醇组加入1×10^-6 mol/L地塞米松和1×10^-7 mol/L佛波醇,星型胞菌素组加入1×10^-6 mol/L地塞米松和1×10^-7 mol/L星型胞菌素,观察不同干预组细胞的增殖或抑制,并对细胞膜及细胞质中蛋白激酶C含量的变化进行检测。 结果与结论：地塞米松可明显的诱导凋亡,加入佛波醇后凋亡明显增加,加入星形孢菌素后凋亡明显减少。加入地塞米松后胞浆的蛋白激酶C明显减少,包膜明显增加。加入地塞米松不同时间,胞浆和胞膜的蛋白激酶C变化在30 min最明显。说明地塞米松诱导成骨细胞凋亡的机制与蛋白激酶C有关,地塞米松为蛋白激酶C激动剂。细胞受到刺激后,胞浆的蛋白激酶C转移至包膜,胞浆中的蛋白激酶C量减少,包膜中的增加。     

The protein kinase C inhibitor,H7, inhibits tumor cell invasion and metastasis in mouse melanoma via suppression of ERK1/2

Protein kinase C (PKC) has been shown to be a signal transducer during tumorigenesis, tumor cell invasion, and metastasis. Recent studies have reported that the PKC inhibitor, 7-hydroxystaurosporine, inhibits tumor cell invasion. However, the molecular mechanisms of this inhibition of invasion and metastasis are not well understood. In the present study, we attempt to clarify the mechanism by which H7, a PKC inhibitor, inhibits tumor cell invasion and metastasis in the melanoma cell line B16BL6. It was found that H7 inhibits B16BL6 cell invasion and metastasis. We also observed that H7 inhibits the mRNA expression and protein activities of matrix metalloproteinase (MMP)-1, -2, -9 and MT1-MMP. Furthermore, H7 suppresses phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2). However, other signal transduction factors, such as p38 mitogen-activated protein kinase (p38MAPK) and c-Jun N-terminal kinase 1/2 (JNK1/2), were unaffected. Moreover, U0126, a MEK1/2 inhibitor, also inhibited B16BL6 cell invasion and metastasis, as well as the mRNA expression and protein activities of MMP-1, -2, -9 and MT1-MMP. This indicates that H7 inhibits signal transduction through the PKC/MEK/ERK pathway, thereby inhibiting B16BL6 cell invasion and metastasis. These results suggest that PKC inhibitors have potential clinical applications in the treatment of tumor cell metastasis.