p38MAK基因诱导胶质瘤细胞凋亡机制的初步研究

目的 初步探讨p38MAPK基因诱导大鼠胶质瘤细胞C6发生凋亡的机制。方法 利用脂质体介导法将p38MAPK基因导入C6细胞中,用夹心法ELISA检测细胞培养液中sTNF-α水平的变化,用流式细胞仪检测膜TNF-α和膜TNFRI水平的变化。结果 转染pCMV5-p38MAPK后,细胞培养液中sTNF-α水平明显升高,膜TNF-α水平无明显变化,膜TNFRI表达升高。结论 p38MAPK可能通过上调sTNF-α和膜TNFRI水平而诱导C6细胞凋亡。     

p38MAPK信号通路与应力介导成肌细胞的凋亡*

背景：在体内条件下,细胞力学的功能研究因其所处生理环境的复杂性、实验条件的不易控制而很难得到满意结果。 目的：在成功构建成肌细胞体外培养-力学刺激模型的基础上,研究p38MAPK信号通路在成肌细胞凋亡中的作用及其机制。 方法：将体外培养的C2C12细胞分为对照组和SB203580组,SB203580组中加入 20 mmol/L的p38MAPK抑制剂SB203580。应用细胞应力加载装置Flecell Strain Unit-5000T给细胞提供15%的力值,分别施加0,6,12,24 h的周期性张应力。每分钟10个循环,每循环包括3 s牵张,3 s松弛。Hoechst 33258染色观察细胞的形态学变化;流式细胞仪检测细胞凋亡情况;RT-PCR法检测促凋亡基因bax mRNA的表达;Western blot检测信号通路中p38MAPK和p-p38MAPK蛋白的表达。 结果与结论：随着加力时间的延长,细胞逐渐出现核固缩及凋亡小体,凋亡率增加(P < 0.05),bax mRNA表达增多(P < 0.05);细胞p38MAPK和p-p38MAPK蛋白均在加力6 h达到最低,此后逐渐升高。p38MAPK抑制剂SB203580可抑制加力引起的细胞凋亡,减少bax mRNA及p38MAPK和p-p38MAPK蛋白的表达(P < 0.05)。说明p38MAPK信号通路在应力介导的成肌细胞凋亡中起到重要的作用。     

p53基因、PTEN基因协同对胶质瘤U251细胞系生长抑制作用的研究

目的探讨p53基因和PTEN基因在脑胶质瘤细胞系U251发生发展过程中的作用机制。方法用不同MOI的p53腺病毒表达载体pAdCMV-p53及空载体pAdCMV-lacZ分别感染表达野生型PTEN基因和突变型PTEN基因的细胞系,RT-PCR及Westernblot方法检测转染效率;并通过MTT检测生长抑制率、流式细胞仪检测细胞周期及TUNEL检测分析细胞凋亡等指标观察p53基因及PTEN基因对U251细胞生长的影响。结果MOI为100时,p53基因可引起U251细胞G0G1期阻滞、诱导细胞凋亡,生长抑制;MOI为50时,U251-p53 PTEN生长抑制率明显高于U251-p53,并能出现细胞凋亡,而U251-p53仅出现少量细胞凋亡。结论p53基因可以通过细胞周期G0G1期阻滞及诱导细胞凋亡抑制胶质瘤细胞系U251的生长;PTEN基因可以促进p53基因对胶质瘤细胞系U251的生长抑制作用,并能增加U251细胞对p53基因诱导凋亡的敏感性。     

p38 MAPK、Caspase-s介导PTH诱导PC12细胞凋亡机制的研究

目的甲状旁腺激素(PTH1-34)对PC12细胞作用和p38MAPK、Caspase-s在PTH1-34对PC12细胞凋亡中作用机制。方法应用CCK-8法测定PTH对PC12细胞生长抑制率,通过细胞形态学、乳酸脱氢酶(LDH)和流式细胞仪方法检测细胞损伤,RT-PCR测定p38 mRNA的表达,通过Western blot检测细胞中p38磷酸化丝裂原活化蛋白激酶(MAPK)及caspase-3蛋白的变化。结果 CCK-8法测定PTH抑制PC12细胞生长;透射电镜可见细胞核呈固缩状、凋亡小体出现等典型的凋亡形态学改变;流式细胞仪可见细胞凋亡率增多;LDH渗出量增多等。PTH1-34可明显上调p38 mRNA的表达,并可明显地促进PC12细胞磷酸化p38MAPK与Caspase-3的蛋白表达。结论 PTH可诱导PC12细胞凋亡,p38MAPK和Caspase-s共同介导参与PTH致PC12细胞凋亡。     

雷公藤红素对C6胶质瘤细胞凋亡及细胞周期阻滞的影响

目的 探讨雷公藤红素对体外C6胶质瘤细胞凋亡及细胞周期阻滞的影响及机制.方法 雷公藤红素处理体外培养的C6胶质瘤细胞,MTT法检测细胞增殖,Hochest33342染色荧光显微镜观察以及锇铀铅染色透射电镜观察胶质瘤细胞形态变化,流式细胞术分析细胞凋亡率及细胞周期改变.蛋白印迹分析检测凋亡相关蛋白及细胞周期调控蛋白的表达变化.结果 雷公藤红素对C6胶质瘤细胞的增殖抑制作用呈浓度和时间依赖性;2.56 μmol/L雷公藤红素处理C6胶质瘤细胞24h后,荧光显微镜、透射电镜下均可见凋亡形态学改变.流式细胞术检查显示,凋亡细胞比例由1.32％升高到19.34％;并且,处于G0/G1期的细胞比例由76.42％降低到54.52％,G2/M期细胞比例由9.29％升高到30.50％.蛋白印迹分析显示,雷公藤红素降低了Bcl -2及XIAP蛋白表达,促进了Bax及Caspase -3的表达以及PARP的剪切;雷公藤红素在诱导细胞周期调控蛋白p21、p27及cyclin B1蛋白表达增加的同时抑制了cdk2蛋白的表达.结论 雷公藤红素能够通过调节凋亡相关蛋白及细胞周期相关因子的表达影响C6胶质瘤细胞的凋亡及细胞周期阻滞.     

转染热休克蛋白70对p38MAPK信号通路的影响

目的：探讨热休克蛋白（HSP70）在人胶质瘤细胞BT-325p38MAPK信号通路中的作用。方法：用脂质体介导法将hsp70基因导入人胶质瘤细胞BT-325中，倒置显微镜观察转染细胞的形态学及粘附性变化，紫外线照射30min后，采用免疫组化和Western-blot方法测定转染前后HSP70的表达水平及照射前后p38MAPK表达情况。结果：免疫组化和Western-blot证实hsp70基因成功转染入BT-325中，转染细胞受到紫外线照射后p38MAPK表达减弱。结论：体外转染hsp70基因可抑制紫外线照射后BT-325细胞p38MAPK的表达。     

NOS反义RNA重组腺相关病毒载体体内提高脑细胞耐缺血能力的实验研究

目的 探讨二种分别携带神经元型一氧化氮合酶(nNOS)、诱导型一氧化氮合酶(iNOS)反义RNA重组腺相关病毒载体(rAAV-AsnNOS和rAAV-AsiNOS)提高脑细胞耐受缺血能力的作用机制.方法 应用立体定位技术将预处理好的病毒载体转染至将要梗死侧的基底节区,转染病毒滴度为2×109mL-1,并将SD大鼠分为4组即rAAV-AsnNOS组,rAAV-AsiNOS组,rAAV-LacZ组和对照组;处理后运用MACO建立缺血模型,每组分为缺血早期和缺血晚期,流式细胞术(FCM)检测NT阳性细胞百分比和细胞凋亡率,逆转录反应系统(RT-PCR)分析nNOS、iNOS,p38MAPK,Caspase-3 mRNA的表达.结果 一定剂量的重组病毒载体转染到大鼠海马区域,无神经损伤症状;转染rAAV-AsnNOS病毒载体的脑神经细胞在缺血早期(缺血1～6 h),NT阳性细胞百分比、细胞凋亡率以及nNOS、p38MAPK和Caspase-3 mRNA表达量均较对照组、rAAV-LacZ组和rAAV-AsiNOS组降低;转染rAAV-AsiNOS病毒载体的脑神经细胞在缺血晚期(缺血24～72 h),NT阳性细胞百分比、细胞凋亡率以及nNOS、p38MAPK和caspase-3 mRNA表达量均较对照组、rAAV-LacZ组和rAAV-AsnNOS组降低,差异有统计学意义.结论 转染重组病毒载体后动物模型脑神经细胞能够耐受缺血损伤,转染rAAV-AsnNOS病毒载体的脑神经细胞能够在缺血早期抑制nNOS、p38MAPK和Caspase-3的表达,转染rAAV-AsiNOS病毒载体的脑神经细胞能够在缺血晚期抑制iNOS、p38MAPK和Caspase-3的表达,从而在缺血后抑制神经细胞凋亡的发生.     

NOS、p38MAPK、Caspase-3介导大鼠脑缺血神经细胞凋亡可能通路的实验研究

目的探讨脑缺血后细胞凋亡发生的可能机制以及神经元型一氧化氮合酶(neuronal nitric oxide synthase,nNOS)、诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)、p38丝裂原活化蛋白激酶(mitogen activated proteinkinasep38,p38MAPK)和半光氨酸蛋白酶-3(caspase-3)在脑缺血后神经细胞凋亡中的共同作用机制。方法采用线栓法闭塞大鼠大脑中动脉(middle cerebral artery occlusion,MACO)建立脑缺血SD大鼠模型,应用透射电镜观察脑缺血对脑组织超微结构的影响,流式细胞仪方法(FCM)分别定量检测细胞凋亡率,半定量RT-PCR检测nNOS、iNOS,p38MAPK和Caspase-3mRNA表达水平。结果透视电镜下脑缺血6h出现核固缩,缺血12h出现细胞核分裂,缺血24h出现凋亡小体;FCM检测细胞凋亡百分率随着缺血时间延长而增加,缺血72h达到高峰,约70.37%;RT-PCR产物的琼脂糖凝胶电泳显示nNOS、iNOS、p38MAPK和Caspase-3mRNA的特异性片段大小分别为501、342、250和342bp,但mRNA表达量不一致,nNOS mRNA主要在缺血早期表达,iNOS、p38MAPK和Caspase-3mRNA在缺血中晚期表达,并在缺血3~5d,后三种基因的表达量达到高峰。结论脑缺血区域发生典型的神经细胞凋亡现象,nNOS来源的NOS在缺血早期发挥神经毒性作用,iNOS来源的NOS在缺血晚期发挥神经毒性作用;NOS,p38MAPK和Caspase-3三种基因的相互关系可能构成介导缺血神经细胞凋亡的通路之一。     

PEX基因修饰骨髓间质干细胞对C6胶质瘤细胞增殖和凋亡的影响

目的探讨PEX基因修饰的骨髓间质干细胞（mesenchymal stem cells,MSC）对C6胶质瘤细胞的作用及机制。方法分子克隆技术构建PEX基因真核表达载体并转染MSC,G418筛选获取稳定表达PEX基因的MSC（MSC-PEX）,将不同数量的MSC-PEX细胞与C6胶质瘤细胞进行共培养试验,用水溶性四氮唑法（WST-1）观察MSC-PEX对C6胶质瘤细胞增殖的影响,用Annexin-Ⅴ-FITC/PI双染荧光观察C6胶质瘤细胞凋亡的形态学变化,并用Annexin-Ⅴ-FITC/PI双标记法通过流式细胞仪检测胶质瘤细胞凋亡率。结果成功获得稳定表达PEX基因的MSC-PEX,MSC-PEX抑制C6胶质瘤细胞的生长作用较明显,Annexin-Ⅴ-FITC/PI双染荧光发现C6胶质瘤细胞发生凋亡形态改变;流式细胞仪检测显示：MSC-PEX转染组和DMEM对照组的凋亡率分别为16.7%和1.3%,差异有统计学意义（P〈0.05）。结论PEX基因修饰的骨髓间质干细胞抑制胶质瘤细胞增殖并诱导其凋亡,为胶质瘤的治疗奠定理论基础。     

氧化应激对大鼠髓核细胞凋亡的影响*

细胞凋亡在椎间盘退变过程中发挥重要作用,而导致细胞凋亡的因素很多,氧化应激是导致细胞凋亡的一个重要因素。 目的：从细胞内信号转导水平验证过氧化氢对大鼠髓核细胞氧化应激损伤的影响。 设计、时间及地点：单一样本观察,试验于2008-03/10在山东省创伤骨科研究所完成。 材料：p38MAPK特异性阻断剂(SB203580)、JNK特异性阻断剂(SP600125)购自碧云天生物技术有限公司;大鼠椎间盘来自2只新生24 h SD大鼠。 方法：原代培养大鼠髓核细胞,将生长良好的髓核细胞制成细胞悬液,随即分为4组：H202组：用0,50,100,200,400,800 μmol/L H2O2刺激;对照组：不加刺激的细胞;SB203580+H2O2组：给予特异性p38MAPK阻断剂SB203580预孵育细胞,再给予H2O2刺激;SP600125+H2O2组：给予特异性JNK阻断剂SP600125预孵育细胞,再给予H2O2刺激。上述处理后检测相关指标。 主要观察指标：以免疫组织化学检测P-p38和P-JNK的表达情况及表达位置;Western印迹法检测SAPK/JNK、p38MAPK及其磷酸化组分的表达。 结果：H2O2能够激活髓核细胞内p38和JNK的活性;SB203580能够有效地抑制p38MAPK的活性,而SP600125则能够有效的抑制JNK的活性;免疫荧光显示P-p38MAPK和P-JNK在细胞质和细胞核均有表达中,而对照组未发现。 结论：大鼠髓核细胞受氧化应激后可通过p38MAPK和JNK通路导致细胞凋亡。     

HSP27 mediates SPARC-induced changes in glioma morphology, migration, and invasion

Secreted protein acidic and rich in cysteine (SPARC) regulates cell-extracellular matrix interactions that influence cell adhesion and migration. We have demonstrated that SPARC is highly expressed in human gliomas, and it promotes brain tumor invasion in vitro and in vivo. To further our understanding regarding SPARC function in glioma migration, we transfected SPARC-green fluorescent protein (GFP) and control GFP vectors into U87MG cells, and assessed the effects of SPARC on cell morphology, migration, and invasion after 24 h. The expression of SPARC was associated with elongated cell morphology, and increased migration and invasion. The effects of SPARC on downstream signaling were assessed from 0 to 6 h and 24 h. SPARC increased the levels of total and phosphorylated HSP27; the latter was preceded by activation of p38 MAPK and inhibited by the p38 MAPK inhibitor SB203580. Augmented expression of SPARC was correlated with increased levels of HSP27 mRNA. In a panel of glioma cell lines, increasing levels of SPARC correlated with increasing total and phosphorylated HSP27. SPARC and HSP27 were colocalized to invading cells in vivo. Inhibition of HSP27 mRNA reversed the SPARC-induced changes in cell morphology, migration, and invasion in vitro. These data indicate that HSP27, a protein that regulates actin polymerization, cell contraction, and migration, is a novel downstream effector of SPARC-regulated cell morphology and migration. As such, it is a potential therapeutic target to inhibit SPARC-induced glioma invasion.     

SB239063,新一代p38丝裂原活化蛋白激酶抑制剂在缺氧缺糖所致SHSY5Y细胞损伤中的作用

目的 探讨SB239063,新一代p38丝裂原活化蛋白激酶(p38MAPK)抑制剂在缺氧缺糖(OGD)所致SHSY5Y细胞损伤中的作用.方法 体外培养SHSY5Y神经母细胞瘤株,以OGD、SB239063(10μmol/L)处理,以MTT检测SHSY5Y细胞活性,以Western blot方法检测p38MAPK活性,应用HEt和fluo-3/AM的荧光强度测定OGD后SHSY5Y细胞超氧化物阴离子和钙离子的浓度.结果 SB239063能提高OGD后SHSY5Y细胞的活性(P<0.01),降低OGD后p38MAPK活性(P<0.05),HEt(P<0.05)和fluo-3/AM荧光强度(P<0.01).结论 SB239063通过抑制p38MAPK的激活,降低细胞内超氧阴离子的浓度,进而抑制细胞内钙超载,从而达到保护SHSY5Y细胞对抗OGD的细胞损害的作用.

Abstract：

Objective To investigate the neuroprotective effect of SB239063,the new p38 mitogen—activated protein kinase (MAPK) inhibitor on SHSY5Y neuronal cells against oxygen-glucose deprivation(OGD),and the mechanisms of the neuroprotective effect.Methods SHSY5Y neuroblastoma cells were exposed to OGD with or without SB239063 (10μmol/L),cell viability was measured by the MTF assay,activity of p38MAPK was measured by western blot,intracellular concentration of superoxide anion and calcium were evaluated via the fluorescence intensity of Het and fluo-3/AM. Resuits Compared with the OGD group.The MTT value was elevated significantly in the SB239063 group(P<0.01),the activitv of p38MAPK decreased significantly in the SB239063 group(P<0.01),the fluorescence intensity of Het(P<0.05)and fluo-3/AM(P<0.01)decreased significantly in the SB239063 group.Conclusion SB239063 protects SHSY5Y neuronal cells against OGD by inhibiting the activity of p38MAPK,then reducing the intracellular concentration of superoxide anion and calcium.     

Activated protein C downregulates p38 mitogen-activated protein kinase and improves clinical parameters in an in-vivo model of septic shock

Despite the success of the anti-coagulant protease protein C (PC) in treating septic shock in humans, the signaling pathways used are still unclear. To explore the effects of treatment with PC zymogen and its activated form aPC in a setting of sepsis, we employed a piglet model of endotoxic shock. In the aPC group, we observed a 65%-90% reduction in plasma TNF-alpha levels and a concomitant clinical improvement. Unexpectedly, administration of aPC also resulted in stabilization of the plasma pH above 7.2. Moreover, phosphorylated p38 mitogen-activated protein kinase (p38MAPK) was virtually absent in the livers of those piglets receiving aPC. In cultured human umbilical vein endothelial cells, we observed that nanomolar concentrations of PC and aPC inhibited the phosphorylation of p38MAPK. Furthermore, we showed that the regulation of the pro-apoptotic cell cycle regulator p53 by PC and aPC is dependent on the reduction of p38MAPK activation. The transduction of these effects involves all three receptors associated with protein C signaling, namely endothelial protein C receptor, protease-activated receptor 1, and sphingosine 1-phosphate receptor 1. Ultimately, this study elucidates novel signaling pathways regulated by protein C and emphasises the pivotal importance of its multiple modes of action beyond anticoagulation. APC's clinical success may, in part, be due to p38MAPK inhibition.     

大黄素甲醚对PC12细胞缺氧损伤的保护作用

目的探讨大黄素甲醚对PC12细胞缺氧损伤的影响。方法体外培养PC12细胞,缺氧处理后给予小同溶浓度大黄素甲醚下预;四甲基偶氮唑盐（MTT）法检测PCI2细胞增殖活性的变化,油镜观察PC12细胞核形态变化,测定上清液中超氧化物歧化酶（SOD）含量,PCR分析丝裂原活化蛋白激酶p38（p38MAPK）和半胱氨酸蛋白酶-3（Caspase-3）的表达。结果缺氧24h后,大黄素甲醚干预后细胞核形态较清楚,偶有肿胀皱缩,少见颗粒样物质形成;大黄素甲醚干预后细胞活性明显增加（P〈0．05）;大黄素甲醚显著增加上清液中SOD含量（P〈0．05）。缺氧12h后PCR结果分析显示,大黄素甲醚显著降低p38MAPK和Caspase-3mRNA表达量（P〈0．01）。结论大黄素甲醚能增强缺氧所致神经元抗损伤能力,对神经元起保护作用。     

Neuroprotective effect of N-acetylcysteine on neuronal apoptosis induced by a synthetic gingerdione compound: involvement of ERK and p38 phosphorylation

Besides being used as a spice, ginger has been applied in oriental medicine to ameliorate symptoms such as inflammatory, rheumatic disorders, and gastrointestinal discomforts. The effects of ginger on neuronal cells, however, have not been explored. We investigate the effect of 1-(3,4-dimethoxyphenyl)-3,5-dodecenedione (I(6)), a derivative of gingerdione, on cultured cortical neurons. After a 5-day maturation period in vitro, cortical neurons were treated with I(6) for 24 hr and cell viability was assessed using MTT assay. I(6) induced neuronal death in a concentration-dependent manner. Hoechst 33342, propidium iodide (PI), and TUNEL staining confirmed that the reduced cell viability by I(6) was due to apoptosis. Pre-treatment of cell with N-acetylcysteine (NAC) prevented cell death in a concentration-dependent manner. N-acetylcysteine increased phosphorylated levels of p42 and p44 extracellular signal-regulated kinases (ERKs). In parallel, farnesyltransferase and MEK inhibitors blocked ERK phosphorylation and neuroprotective effect of NAC. Unexpectedly, NAC also increased phosphorylated level of p38 mitogen-activated protein kinase (MAPK) and p38 specific inhibitors dose-dependently attenuated the effect of NAC. Farnesyltransferase and MEK inhibitors completely abolished NAC-induced p38 phosphorylation whereas p38 inhibitor did not influence NAC-induced ERK phosphorylation. These results show that NAC serially activates ERKs and p38 MAPK, and ERKs and p38 work together to mediate the neuroprotective effect of NAC.     

Neuronal COX-2 expression and phosphorylation of pRb precede p38 MAPK activation and neurofibrillary changes in AD temporal cortex

In Alzheimer's disease (AD) brain, increased levels of cyclooxygenase-2 (COX-2), cell cycle markers, and p38 MAP kinase (MAPK) can be detected in neuronal cells. Besides mediating COX-2 expression, p38 MAPK is suggested to mediate cell cycle progression through phosphorylation of the retinoblastoma protein (pRb). In this study, we show that neuronal immunoreactivity for phosphorylated p38 MAPK does not correlate with COX-2 or phosphorylated pRb (ppRb) in control and AD temporal cortex. Immunoreactivity for activated p38 MAPK co-localizes with AT8 immunoreactivity and increases with the occurrence of neurofibrillary tangles and plaques. On the other hand, COX-2 immunoreactivity co-localizes and correlates with ppRb immunoreactivity in pyramidal neurons. COX-2 and ppRb do not co-localize with AT8 and decrease with increasing pathology. These results suggest that p38 MAPK does not mediate COX-2 expression and pRb inactivation, which are involved in cellular changes in pyramidal neurons early in AD pathogenesis.     

Regulation of a Ca2+-activated K+ channel by calcium-sensing receptor involves p38 MAP kinase

By using pharmacological and molecular approaches, we previously showed that the G-protein-coupled, extracellular calcium (Ca2+(o))-sensing receptor (CaR) regulates a large-conductance (approximately 140 pS), Ca(2+)-activated K+ channel [IK(Ca); CAKC] in U87 astrocytoma cells. Here we show that elevated Ca2+(o) stimulates extracellular-signal-regulated kinase (ERK1/2) and p38 MAP kinase (MAPK). The effect of high Ca2+(o) on p38 MAPK but not ERK1/2 is CaR mediated, insofar as transduction with a dominant-negative CaR (R185Q) using recombinant adeno-associated virus (rAAV) attenuated the activation of p38 MAPK but not of ERK1/2. p38 MAPK activation by the CaR is likely to be protein kinase C (PKC) independent, in that the pan-PKC inhibitor GF109203X failed to abolish the high-Ca2+(o)-induced phosphorylation of p38 MAPK. Consistently with our data on the activation of this kinase, we observed that inhibiting p38 MAPK blocked the activation of the CAKC induced by the specific pharmacological CaR activator NPS R-467. In contrast, inhibiting MEK1 only transiently inhibited the activation of this K+ channel by NPS R-467, despite the continued presence of the antagonist. Similarly to the lack of any effect of the PKC inhibitor on the activation of ERK1/2 and p38 MAPK, inhibiting PKC had no effect on NPS R-467-induced activation of this channel. Therefore, our data show that the CaR, acting via p38 MAPK, regulates a large-conductance CAKC in U87 cells, a process that is PKC independent. Large-conductance CAKCs play an important role in the regulation of cellular volume, so our results have important implications for glioma cell volume regulation.     

Heat shock induces neurite outgrowth in PC12m3 cells via the p38 mitogen-activated protein kinase pathway

We investigated the role of the p38 mitogen-activated protein kinase (MAPK) pathway in heat-shock-induced neurite outgrowth of PC12 mutant cells in which nerve growth factor (NGF)-induced neurite outgrowth is impaired. When cultures of the PC12 mutant (PC12m3) cells were exposed to heat stress at 44 degrees C for 10 min, activity of p38 MAPK increased and neurite outgrowth was greatly enhanced. The neurite extension was inhibited by the p38 MAPK inhibitor BS203580. Longer heat treatment of PC12m3 cells provoked cell death, which was enhanced by SB203580. These findings suggest that heat-induced activation of p38 MAPK is responsible for the neurite outgrowth and survival of PC12m3 cells.     

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine has a transient proliferative effect on PC12h cells and nerve growth factor additively promotes this effect: possible involvement of distinct mechanisms of activation of MAP kinase family proteins

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a potent inducer of cell death, producing reactive oxygen species (ROS) and causing apoptosis in PC12h cells at 1 mM [Shimoke et al., J. Neurosci. Res. 63 (2001) 402-409]. We showed here that MPTP also had a weak proliferative effect on PC12h at 500 microM when treated for 24 h. The proliferative effect was additive within 24 h cells when nerve growth factor (NGF) was present in the culture medium, but NGF promoted cell differentiation 2 or 3 days after. Use of PD98059, a specific inhibitor of MEK1 located upstream of extracellular signal-regulated kinases (ERKs), revealed that the NGF- and MPTP-induced proliferative effect depends on the MEK1 pathway because PD98059 diminished the proliferation completely, and interestingly, NGF and MPTP promoted sustained activation of ERKs. Moreover, we observed that MPTP increased the activity of p38 MAPK but not c-jun N-terminal kinase (JNK) in 30 min. We also observed that SB203580, a specific inhibitor of p38 MAPK, decreased cell viability. These results suggest that NGF and MPTP cooperate to promote acute cell proliferation via the sustained ERKs and the p38 MAPK pathway within 24 h in PC12h cells.