1-甲基-4-苯基吡啶离子调控线粒体自噬对线粒体氧化应激损伤的影响

目的 探讨1-甲基-4-苯基吡啶离子(MPP+)诱导线粒体自噬在帕金森病(PD)发病机制中的作用.方法 将细胞分为MPP+(0 mmol/L)对照组、MPP+(1 mmol/L)处理组和MPP+ (2 mmol/L)处理组,共同转染EGFP-LC3和RFP-MI-TO后加入MPP+处理48 h.Western blot检测细胞自噬水平的变化,甲丹磺酸尸胺(MDC)检测自噬空泡聚集,免疫荧光法检测EGFP-LC3和RFP-MITO亚细胞共定位,流式技术检测线粒体膜电位及活性氧.结果 MPP+1 mmol/L及MPP+2 mmol/L组LAMP2A、Beclin1和LC3-Ⅱ/LC3-Ⅰ的灰度值与对照组相比均上调,差异有统计学意义(P＜0.05).与对照组相比,MPP+处理组自噬水平增加,自噬空泡增加,外源性LC3表达上调,EGFP-LC3和RFP-MITO存在亚细胞共定位.MPP+1 mmol/L及MPP+2 mmol/L组线粒体膜电位较对照组降低;MPP+1 mmol/L及MPP+2 mmol/L组线粒体活性氧较对照组增加,差异均有统计学意义(P＜0.05).结论 MPP+通过调控线粒体自噬水平致线粒体氧化应激损伤.     

突变型α-核突触蛋白的自噬性降解途径及可能机制

目的 观察突变型α-核突触蛋白对PC12细胞增殖的影响和可能的降解途径,探讨其在帕金森病发病机制中的作用.方法 对转染了α-核突触蛋白(A30P)的PC12细胞进行药物干预,检测细胞的增殖活性,并采用透射电镜观察细胞超微结构改变以及自噬的特征性改变,同时检测α-核突触蛋白的表达和超氧化物歧化酶(SOD)的水平.结果 (1)Western Blot法检测α-核突触蛋白的表达:A30P+渥曼青霉素组(A30P+W组)、A30P+1-甲基4-苯基吡啶组(A30P+MPP+组)较A30P组明显增高,以A30P+W组最为明显;而A30P+雷帕霉素组(A30P+R组)条带较A30P组减低(P＜0.01);(2)不同时间点细胞培养液中SOD水平(U/ml)的测定:用MPP+处理转染了突变型α-核突触蛋白的PC12细胞后,培养液中SOD水平(A30P+MPP+组:3 h:97.49±13.8;12 h:102.7±12.7:24 h:101.5±11.8;48 h:104.3±12.4)较A30P组在各时间点显著下调(t=3.7721,P=0.0017);A30P+R组在给药12 h以后,培养液中SOD水平逐渐升高,其中在24 h(121.2±13.0)、48 h(124.3±14.1)和72 h(127.7±13.7)时与A30P+W组比较差异有统计学意义(t=2.9746,P=0.0083);突变型α-核突触蛋白激活了自噬途径,并介导了MPP+的毒性作用,自噬抑制剂渥曼青霉素可通过抑制自噬而加剧α-核突触蛋白积聚,导致细胞死亡;而自噬诱导剂雷帕霉素则可以通过诱导自噬的发生而促进α-核突触蛋白的降解和细胞生长.结论 α-核突触蛋白的异常积聚导致PC12细胞的自噬性细胞死亡,促进自噬有助于突变型α-核突触蛋白降解,对细胞具有保护作用.     

1-methyl-4-phenylpyridinium ion induced autophagic stress and caused autophagic clearance impairment of α-synuclein in pheochromocytoma cells

Objective To investigate the role of autophagie stress induced by 1-methyl-4-phenylpyridinium (MPP+) in pheochromocytoma (PC12) cell injury,and the mechanism of autophagic clearance impairment and abnormal aggregation of α-synuelein.Methods Before and after treatment of MPP+,the viability was measured through the MTT assay,and the expression of α-synuclein and microtubule-associated protein light chsin 3-Ⅱ(LC3.Ⅱ)in the level of protein was detected through Western blot.In addition,MDC staining and immunofluorescence microscopy were performed to observe the alterations of autophagy and the signals for α-synuelein,LC3-Ⅱ,lysosomal-associated membrane protein 1(LAMP-1)and their co-localization in PC12 and A30P cells.Results After treatment of MPP+ for 24 h,cell viability decreased in PC12 + MPP+ group and A30P + MPP+ group.Theincrease in α-synuelein was significant in the level of protein in PC12 + MPP+ group (0.66±0.07,t=5.7271,P＝0.0023) and A30P + MPP+ group(1.71±0.40,t=8.6100,P=0.0005),especially in A30P + MPP+ group,compared with the untreated groups (PC12 group:0.20±0.08;A30P:O.76±0.09).In MPP+ -treated groups,LC3-Ⅱ protein and the average number of late autophagic vacuoles per cell increased compared with untreated ones.Besides,the signals for LC3-Ⅱ and α-synuclein and the extent of their co-localization increased in MPP+ -treated groups.Though the signals for LAMP-1 that labeles lysosome increased,the extent of co-localization between LAMP-1 and LC3-Ⅱ was reduced after treated with MPP+ for 24 h.Conclusions MPP+impaires the fusion of autophagosomes and lysosomes,leading to the autophagicclearance impairment of α-synuclein and autophagic stress,and finally causes the cell damage even death.     

Aβ_(1-42)寡聚体对α-syn过表达SHSY5Y~(A53T)细胞自噬功能的影响

目的构建人A53T突变型α-突触核蛋白过表达的SHSY5Y细胞模型,观察Aβ_(1-42)寡聚体对细胞的毒性作用和自噬功能的影响。方法利用慢病毒稳转方法构建A53T突变型α-突触核蛋白过表达的SHSY5Y细胞及空载体对照细胞,RT-qPCR方法检测SHSY5Y细胞中α-突触核蛋白mRNA的表达。用Aβ_(1-42)寡聚体干预两组细胞24 h,CCK-8法检测Aβ_(1-42)寡聚体对细胞增殖的影响,Western Blot检测细胞自噬相关蛋白的表达水平。结果慢病毒转染SHSY5Y细胞后,过表达组细胞内α-突触核蛋白表达水平较正常细胞组及开载体对照组增加,差异有统计学意义(P0.001);人A53T突变型α-突触核蛋白过表达不影响细胞的增殖;不同浓度Aβ_(1-42)寡聚体(0、0.5μmol/L、1.25μmol/L、2.5μmol/L、5μmol/L、10μmol/L)处理细胞24 h后,细胞增殖抑制率成浓度依赖性;Aβ_(1-42)寡聚体处理后,α-突触核蛋白过表达组细胞LC3-Ⅱ,Beclin-1自噬蛋白表达水平较对照组细胞显著降低(P0.05)。结论人A53T突变型α-突触核蛋白过表达不影响的SHSY5Y细胞增殖,Aβ_(1-42)寡聚体对α-突触核蛋白过表达细胞具有显著毒性,对细胞的损伤机制可能通过抑制细胞自噬功能。     

有氧锻炼通过TFEB-自噬溶酶体途径减轻慢性脑缺血大鼠认知功能障碍的研究

目的观察有氧锻炼对慢性脑缺血大鼠TFEB-自噬溶酶体途径及认知功能障碍的影响。方法 SD大鼠随机分为3组:对照组、慢性脑缺血组和慢性脑缺血+有氧锻炼组。用双侧颈总动脉结扎的方法建立慢性脑缺血模型。有氧锻炼组进行跑步锻炼12w。用Morris水迷宫比较各组大鼠的空间学习能力。用苏木精-伊红染色比较各组大鼠海马神经元损伤的状况。用Western-blotting比较各组大鼠海马组织LC3Ⅱ/LC3Ⅰ、p62、LAMP-1、CTSD以及核内TFEB的含量。结果与对照组相比,慢性脑缺血组大鼠平均逃避潜伏期显著延长,隐匿平台象限停留时间显著缩短,通过隐匿平台次数显著降低;形态异常的海马神经元显著增加,Western-blotting显示,LC3/LC3、LAMP-1、CTSD以及核内TFEB显著降低,p62显著升高,差异具有统计学意义(P 0.05);与慢性脑缺血组相比,有氧锻炼组大鼠平均逃避潜伏期显著缩短,隐匿平台象限停留时间显著延长,通过隐匿平台次数显著增加;形态异常的海马神经元显著减少,LC3Ⅱ/LC3Ⅰ、LAMP-1、CTSD以及核内TFEB显著升高,p62显著降低;差异有统计学意义(P 0.05)。结论有氧锻炼通过激活TFEB-自噬溶酶体途径减轻慢性脑缺血所致的大鼠认知功能障碍。     

重症肌无力外周血调节性T细胞线粒体自噬异常的研究

目的探讨线粒体自噬对重症肌无力(myasthenia Gravis,MG)患者外周血调节性T细胞(CD4~+CD25~+regulatory T cell,Treg)功能的影响及关系。方法选择首次确诊、尚未接受治疗的15例MG患者,以15名健康人作为对照,分别采集外周血,以磁珠分选法获得Treg细胞,经流式细胞仪鉴定纯度后,分别通过透射电镜检测Treg细胞线粒体自噬情况、Western Blot法检测微管相关蛋白轻链3-Ⅱ(microtubule associated protein light chain 3-Ⅱ,LC3-Ⅱ)的表达水平、JC-10荧光探针检测线粒体膜电位(以红色荧光细胞数/绿色荧光细胞数比值表示)变化、羧基荧光素琥珀酰亚胺酯(CFDA-SE,CFSE)检测Treg对正常CD4~+T细胞增殖抑制能力(荧光强度越强,增殖抑制能力越强)。结果与对照组比较,MG组电镜下线粒体自噬明显减少[(25.60±7.81)个、(19.20±5.49)个,t=-2.596,P0.05],且变形线粒体较多;MG组LC3-Ⅱ表达明显减少(0.450±0.137、0.334±0.124,t=-2.413,P0.05);MG组Treg细胞线粒体膜电位下降(2.153±0.537,1.726±0.494,t=2.126,P0.05);MG组CFSE检测平均荧光强度减弱(34.82±10.64、26.49±5.94,t=2.646,P0.05)。结论 MG患者有Treg细胞的线粒体自噬功能降低,这可能与其增殖抑制功能降低相关。     

1-甲基-4-苯基吡啶离子对人神经母细胞瘤细胞株哺乳动物雷帕霉素靶位信号通路的影响

目的研究1-甲基-4-苯基吡啶离子(MPP+)对人骨髓神经母细胞瘤细胞株SH-SY5Y细胞哺乳动物雷帕霉素靶位(mTOR)信号通路相关蛋白表达的影响。方法体外培养的SH-SY5Y细胞分为正常对照组、MPP+0.25 mmol/L组、0.5 mmol/L组及1 mmol/L组,各MPP+组细胞与含相应浓度的MPP+培养24 h。采用四甲基偶氮唑盐(MTT)法检测各组细胞相对存活率;应用免疫印迹法检测各组细胞中mTOR蛋白、核糖体蛋白S6激酶(p70S6K)、mTOR调控相关蛋白(Raptor)、雷帕霉素不敏感的mTOR伴侣蛋白(Rictor)以及与自噬相关的微管相关蛋白1轻链3(LC3Ⅱ)、Beclin1蛋白表达水平。结果与正常对照组比较,各MPP+组细胞相对存活率显著降低(P<0.05～0.001);mTOR、p70S6K、Raptor、Rictor表达明显降低(P<0.05～0.001);LC3Ⅱ和Beclin1表达显著升高(P<0.05～0.001),均呈现出明显的量效关系。结论 MPP+通过抑制细胞中mTOR信号通路,诱导SH-SY5Y细胞自噬性死亡,并且与MPP+的浓度相关;这可能是MPP+导致PD动物模型发病的机制。     

帕金森病细胞模型中维生素C调控SIRT3影响自噬水平的研究

目的探讨维生素C(Vit C)通过调控沉默信息调解转录因子3(SIRT3)影响帕金森病模型中PC12细胞自噬的意义和作用机制。方法培养拟神经元PC12细胞株,随机分组为:正常对照组(Control组)、单纯Vit C组(Vit C组)、帕金森病组(MPP~+组)和Vit C治疗组(Vit C+MPP~+组),在含有Vit C组中分别加入400μmol/L Vit C孵育6 h后,在含有MPP~+组中均加入700μmol/L MPP~+,模拟帕金森病的神经细胞损伤,孵育48 h后,利用细胞增殖-毒性检测试剂盒(cell counting Kit-8,CCK-8)检测细胞存活率;利用小鼠乳酸脱氢酶(LDH)试剂盒检测LDH变化; Western blot(WB)检测PC12细胞中SIRT3、微管相关蛋白1轻链3(LC3-Ⅱ)的表达变化情况,免疫荧光检测细胞SIRT3、LC3-Ⅱ的表达变化情况。结果 CCK-8和LDH检测结果提示,Vit C能改善细胞生存环境,明显减轻帕金森病PC12细胞损伤,提高细胞活力;同样的,WB结果提示,与MPP~+组比较,Vit C上调SIRT3和LC3-Ⅱ的表达,促进神经元自噬的发生,组间差异有统计学意义(P 0. 05);同样的,免疫荧光结果显示,Vit C+MPP~+组中SIRT3和LC3-Ⅱ荧光强度均较MPP~+组增加。结论 Vit C可以激活SIRT3表达,并提高细胞自噬,发挥一种内源性的神经保护作用,拮抗MPP~+对PC12细胞的损伤。     

自噬和蛋白酶体降解途径在突变型α-突触核蛋白PC12细胞凋亡中的作用

目的 利用建立好的转染A53T突变型α-突触核蛋白的大鼠嗜铬细胞瘤(PC12)细胞株,探讨自噬和泛素-蛋白酶体通路在细胞凋亡途径中的具体作用.方法 选择特异性蛋白酶体抑制剂和大自噬抑制剂及诱导剂作用于稳定转染的A53T细胞株,四甲基偶氮唑盐法和流式细胞仪检测细胞活力和各组细胞凋亡率,电镜观察超微结构,并测定细胞培养液中NO的活力和热休克蛋白70(Hsp70)及Caspase-3蛋白表达.结果 蛋白酶体抑制剂环氧霉素(100 nmol/L)和(或)大自噬抑制剂3-MA(10 mmol/L)处理A53T细胞24 h后环氧霉素组、3-MA组和环氧霉素+3-MA组细胞活力(A值分别为0.23±0.01、0.19±0.01、0.17±0.01)较对照A53T细胞组(A值为0.32±0.06)明显下降(P<0.05);而大自噬诱导剂雷帕霉素(0.2 μg/ml)处理后细胞存活率(A值为0.44±0.08)显著高于其余用药组.与对照组(1.55%±1.15%)相比,3-MA、环氧霉素、环氧霉素+3-MA组作用24 h后A53T细胞的凋亡百分率(分别为4.74%±0.91%、4.59%±1.18%、5.40%±1.75%)显著增高(P<0.05),而大自噬诱导剂下调蛋白酶体抑制剂导致的凋亡;蛋白酶体抑制剂组NO和Hsp70蛋白含量也明显高于对照组.结论 大自噬和蛋白酶体途径障碍促进了凋亡发生,抑制或诱导自噬对Hsp70和NO的影响不如蛋白酶体途径对其影响大.     

溶酶体自噬途径降解α—synuclein蛋白作用研究

目的探讨α—synuclein蛋白细胞内溶酶体途径降解机制。方法用神经生长因子NGF诱导分化PCI2细胞作为研究多巴胺能神经元的细胞载体,应用鱼藤酮处理PCI2细胞建立α-synuclein蛋白细胞模型。使用溶酶体途径降解抑制剂E64处理神经元样分化的PCI2细胞,应用免疫荧光双标方法观察PCI2细胞内硫黄素S、α—synuclein蛋白阳性聚集包涵体形成情况,比较各组的差异。结果用E64处理鱼藤酮预处理过的PCI2细胞后α—synuclein蛋白聚集且较多包涵体形成（15．36±0．85）％,与对照组相比差异有统计学意义（P〈0．05）。结论溶酶体自噬途径可能在α—synuclein蛋白降解、聚集和多巴胺神经元死亡过程中发挥重要作用。     

β淀粉样蛋白_（1-42）促进转染人α-突触核蛋白A53T突变基因的PC12细胞内α-突触核蛋白的表达

目的：探讨β淀粉样蛋白1-42（Aβ1-42）促进转染人α-突触核蛋白（α-Syn）A53T突变基因的PC12细胞（A53T细胞）内α-Syn的表达及维生素C对A53T细胞保护作用的机制。方法：对高表达α-Syn的A53T细胞分别采用PBS、Aβ1-42和Aβ1-42＋维生素C干预。用MTT法检测细胞活性和Western blot检测不同干预后A53T细胞α-Syn表达量。结果：①随着Aβ1-42浓度增加,细胞活性呈浓度依赖性降低;维生素C可减轻细胞损伤。②Western blot检测结果提示维生素C可减轻α-Syn的谱带密度;Aβ1-42干预后A53T细胞内α-Syn表达量相对值为（0.76±0.13）,维生素C干预后α-Syn表达量相对值为（0.23±0.08）,两者差异有统计学意义（P〈0.01）。结论：Aβ1-42可导致高表达α-Syn的A53T细胞损伤,并促进α-Syn的表达;维生素C可部分拮抗该效应,对神经细胞具有一定的保护作用。     

The effect of α-synuclein knockdown on MPP+ toxicity in models of human neurons

The protein α-synuclein is central to the pathophysiology of Parkinson’s disease (PD) but its role in the development of neurodegeneration remains unclear. α-Synuclein-knockout mice develop without gross abnormality and are resistant to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a mitochondrial inhibitor widely used to model parkinsonism. Here we show that differentiated human dopaminergic neuron-like cells also have increased resistance to 1-methyl-4-phenylpyridine (MPP+), the active metabolite of MPTP, when α-synuclein is knocked down using RNA interference. In attempting to understand how this occurred we found that lowering α-synuclein levels caused changes to intracellular vesicles, dopamine transporter (DAT) and vesicular monoamine transporter (VMAT2), each of which is known to be an important component of the early events leading to MPP+ toxicity. Knockdown of α-synuclein reduced the availability of DAT on the neuronal surface by 50%, decreased the total number of intracellular vesicles by 37% but increased the density of VMAT2 molecules per vesicle by 2.8-fold. However, these changes were not associated with any reduction in MPP+-induced superoxide production, suggesting that α-synuclein knockdown may have other downstream effects which are important. We then showed that α-synuclein knockdown prevented MPP+-induced activation of nitric oxide synthase (NOS). Activation of NOS is an essential step in MPTP toxicity and increasing evidence points to nitrosative stress as being important in neurodegeneration. Overall, these results show that as well as having a number of effects on cellular events upstream of mitochondrial dysfunction α-synuclein affects pathways downstream of superoxide production, possibly involving regulation of NOS activity.     

姜黄素通过诱导热休克蛋白70保护多巴胺能细胞

目的 探讨姜黄素通过诱导热休克蛋白70(Hsp70)高表达,抑制α-突触核蛋白的异常表达和聚集,促进蛋白酶体系统降解异常α-突触核蛋白对多巴胺能细胞的保护作用.方法 选用大鼠嗜铬细胞瘤细胞株(PCI2细胞),鱼藤酮诱导其损伤建立帕金森病细胞模型,利用姜黄素进行干预:采用MTT法检测细胞活力,荧光酶标仪检测蛋白酶体水解酶活性,Western blot检测Hsp70和α-突触核蛋白的表达,免疫荧光法检测细胞内Hsp70的表达和α-突触核蛋白的聚集.结果 鱼藤酮组PC12细胞活力及蛋白酶体水解酶活性明显降低,Hsp70的表达轻度增加,α-突触核蛋白表达和聚集明显增加,与对照组比较差异有统计学意义(P<0.05).经不同浓度姜黄素预处理4h后与0.1 μmol/L鱼藤酮共同孵育PC12细胞24 h,与鱼藤酮组比较,0.5 μmol/L和1.0 μmol/L姜黄素使细胞活力以及蛋白酶体水解酶活性明显升高,Hsp70表达明显升高,α-突触核蛋白的表达和聚集明显减少,差异有统计学意义(P<0.05);5.0 μmol/L和10 μmol/L姜黄素对鱼藤酮的拮抗作用明显减弱,细胞活力与鱼藤酮组比较差异均无统计学意义(P>0.05),胰蛋白酶、多肽-谷氨酰-多肽水解酶活性与鱼藤酮组比较差异均无统计学意义(P>0.05);10 μmol/L姜黄素组糜蛋白酶样水解酶活性进一步降低,与鱼藤酮组比较差异有统计学意义(P<0.05).结论 低浓度姜黄素能够通过诱导PC12细胞表达Hsp70,诱导蛋白酶体水解酶活性表达,进而抑制α-突触核蛋白的表达和聚集,从而拮抗鱼藤酮诱导的PC12细胞的损伤.     

H2O2预处理通过ERK1/2和p38 MAPK信号通路上调14-3-3蛋白在PC12

OBJECTIVE: To investigate the protective effects of hydrogen peroxide preconditioning (HPP) on the pheochromocytoma (PC12) cells treated with 1-methyl-4-phenylpyridinium (MPP(+)) and to explore the potential mechanisms. METHODS: The viability and apoptosis of PC12 cells were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and 4',6'-diamidino-2-phenylindole (DAPI) staining, respectively. The expressions of 14-3-3 protein and phosphorylated p38 mitogen-activated protein kinase (MAPK) were determined by Western blot. Enzyme-linked immunosorbent assay (ELISA) was used to measure the activity of extracellular signal-regulated protein kinase 1/2 (ERK1/2). RESULTS: The cell viability decreased and the number of apoptotic cells increased dramatically in MPP(+) group compared with that in Control group. HPP induced a significant increase in cell viability and a marked decrease in population of apoptotic cells of the MPP(+)-treated PC12 cells, accompanied with up-regulation of 14-3-3 protein and increase of ERK1/2 and p38 MAPK activities. The 14-3-3 protein expression was positively correlated with the phosphorylation of ERK1/2. Furthermore, inhibition of the ERK1/2 with PD98059 abolished the 14-3-3 protein up-regulation in PC12 cells induced by HPP. CONCLUSION: HPP protects PC12 cells against MPP(+) toxicity by up-regulating 14-3-3 protein expression through the ERK1/2 and p38 MAPK signaling pathways.     

活化素A对MPP^＋所诱导的PC12细胞损伤的保护作用

目的观察重组人活化素A(rhAcT)对MPP+所诱导的PC12细胞损伤的保护作用.方法将MMP+或活化素A,L-deprenyl加入体外培养的PC12细胞,用四甲基偶氮唑盐(MTT)法检测细胞活力的变化;用免疫细胞化学法和RT-PCR评价细胞的酪氨酸羟化酶和bcl-2蛋白及mRNA含量的变化,用脱氧核苷酸末端转移酶介导的缺口末端标记法(TUNEL)检测细胞凋亡的变化,比较各组的差异.结果预先给予rhAcT和L-deprenyl的两组细胞活力明显高于MPP+损害组,酪氨酸羟化酶和bcl-2的蛋白及mRNA表达强于损害组,同时两组的凋亡细胞明显减少,rhAcT和L-deprenyl两组间无显著差异.结论rhAcT和L-deprenyl通过上调bcl-2的表达,抑制凋亡的发生,而对MMP+所诱导的PC12细胞的损伤具有保护作用.     

微管相关蛋白LC3B-Ⅱ和自噬基因Beclin1在星形细胞肿瘤中的表达及其意义

目的 探讨微管相关蛋白1轻链3B(MAP1-LC3B)和自噬相关基因Beclin1在星形细胞肿瘤中的表达及其与星形细胞肿瘤病理和临床表现的相关性及意义.方法 选择上海长征医院神经外科2006年1月至2006年12月住院手术治疗的初发性星形细胞肿瘤患者62例,其中Ⅰ级(毛细胞性星形细胞瘤)4例,Ⅱ级(星形细胞瘤)23例,Ⅲ级(间变性星形细胞瘤)12例,Ⅳ级(胶母细胞瘤)23例.免疫组织化学染色检测肿瘤标本中Beclin 1的表达,免疫印迹法检测Beclin 1和MAP1-LC3B的表达并统计Beclin 1、MAP1-LC3B的表达与星形细胞肿瘤临床病理表现的关系.结果免疫组化显示Ⅰ～Ⅳ级星形细胞肿瘤中Beclin 1的表达随肿瘤级别的升高而降低,差异有统计学意义(P＜0.05).免疫印迹检测结果显示不同病理分级、生存期患者Beclin 1的表达差异有统计学意义(P＜0.05),不同病理分级患者MAP1-LC3B-Ⅱ表达的差异有统计学意义(P＜0.05);相关性分析显示MAP1-LC3B-Ⅱ、Beclin 1在星形细胞肿瘤中的表达与病理分级呈负相关关系(r=-0.334,P=0.007;r=-0.448,P=0.000),MAP1-LC3B-Ⅱ、Beclin 1在星形细胞肿瘤中的表达与生存时间呈正相关关系(r=0.285,P=0.027;r=0.359,P=0.005).MAP1-LC3B-Ⅱ和Beclin 1的表达之间也呈正相关关系(r=0.272,P=0.035).结论 MAP1-LC3B-Ⅱ和Beclin 1在胶母细胞瘤中的表达下调,自噬活性的改变可能与星形细胞肿瘤的发生、发展相关.

Abstract：

Objective To investigate the expressions of microtubule -associated protein 1 (MAP1) light chain 3B (LC3B) and autophagy-related gene Beclin1 in astrocytic tumors, and explore their correlations with the pathological features and clinical manifestations of astrocytic tumors to further reveal their roles in tumorigenesis and development of astrocytic tumors. Methods Sixty-two specimens with different-grade astrocytic tumors, including 4 with grade Ⅰ (pilocytic astrocytoma), 23 with grade Ⅱ (astrocytoma), 12 with grade Ⅲ (anaplastic astrocytoma) and 23 with grade Ⅳ (glioblastoma multiforme), were selected in our study. Immunohistochemistry was employed to detect the expression of Beclin1; the expressions of MAP 1-LC3B and Beclin1 were detected by Western blotting.The correlations between expressions of MAP 1-LC3B and Beclin 1 and both the pathological features and clinical manifestations of astrocytic tumors were analyzed. Results Immunohistochemistry showed decreased Beclin1 expression in the astrocytic tumors following the increase of tumor grades (P＜0.05).Western blotting indicated that the expressions of Beclin1 in tumors with different grades and these patients with different life cycles were significantly different (P＜0.05) and the average optical density ratio of Beclin1 in high-grade astrocytic tumors (grade Ⅲ/Ⅳ) was obviously lower than that in low-grade astrocytic tumors (grade Ⅰ/Ⅱ, P＜0.05). The expressions of LC3B-Ⅰ showed significant differences in different-grade astrocytic tumors, and the expression of LC3B-Ⅰ of grade Ⅳ tumor was statistically lower than that of grade Ⅰ, Ⅱ and Ⅲ tumors(P＜0.05). The expressions of LC3B-Ⅱ and Beclin 1 were negatively correlated to the pathological grade of the tumors (r=-0.334, P=0.007; r=-0.448, P=0.000), but positively correlated to the survival time(r=0.285, P=0.027; r=0.359, P=0.005). The expressions of LC3B-Ⅱ and Beclin 1 had a positive correlation (r=0.272, P=0.035). Conclusion Expressions of LC3B-Ⅱ and Beclin1 are down-regulated in glioblastoma multiforme; the decrease of autophagic capacity may relate to the tumorigenesis and development of astrocytic tumors.     

大鼠蛛网膜下腔出血后细胞外调节蛋白激酶1/2激活介导海马区神经细胞自噬

目的探讨大鼠蛛网膜下腔出血(subarachnoid hemorrhage,SAH)后海马区细胞外调节蛋白激酶1/2(extracellular regulated protein kinases,ERK1/2)激活与神经细胞自噬的关系。方法 120只雄性SD大鼠随机分成假手术组、SAH组、ERK1/2抑制剂U0126组、自噬诱导剂雷帕霉素(rapamycin,Rap)组。采用枕大池二次注血法制作SAH大鼠模型;U0126组和Rap组分别于造模前30min侧脑室注射U0126(5μg/μL)和Rap(10nmol/μL)。光镜观察海马区神经细胞形态结构;免疫组化法和实时荧光定量PCR法检测海马区磷酸化ERK1/2(p-ERK1/2)、ERK1/2 mRNA和自噬标志蛋白(Beclin-1和Beclin-1mRNA、LC3-Ⅱ和LC3mRNA)表达水平。结果与假手术组比较,SAH组神经细胞死亡率增加(14.9%±5.7%,28.3%±9.8%,44.2%±10.9%)(q值依次为27.56、35.65、44.81;均P0.05),ERK1/2 mRNA、Beclin-1 mRNA和LC3 mRNA水平增加(1.83±0.01,2.82±0.06,1.34±0.04;1.46±0.02,1.76±0.02,1.35±0.02;1.52±0.04,1.89±0.01,1.31±0.04)(q值依次为42.99、60.66、48.08,71.26、72.46、49.50,48.49、82.40、41.18;均P0.05),p-ERK1/2、Beclin-1和LC3–Ⅱ蛋白水平增加(均P0.05);与SAH组比较,U0126组神经细胞死亡率增加(19.6±6.5%,36.2±7.7%,58.2±12.7%)(q值依次为9.59、10.43、14.66;均P0.05),U0126组ERK1/2 mRNA、Beclin-1 mRNA和LC3 mRNA表达降低(1.23±0.02,1.40±0.02,1.12±0.02;1.22±0.04,1.48±0.06,1.24±0.03;1.34±0.04,1.33±0.02,1.14±0.04)(q值依次为75.66、65.35、31.11,37.18、26.70、15.56,16.79、51.85、22.58;P0.05),p-ERK1/2、Beclin-1和LC3–Ⅱ蛋白水平降低(P0.05);与SAH组比较,Rap组神经细胞死亡率降低(9.1%±4.6%,18.8%±8.6%,28.21%±9.2%)(q值依次为11.86、12.54、16.74;均P0.05),Rap组Beclin-1mRNA和LC3mRNA增加(1.78±0.02,2.27±0.05,1.86±0.04;1.97±0.06,2.31±0.08,1.85±0.00)(q值依次为49.57、48.63、72.12、41.96、38.88、71.73;P0.05),Beclin-1和LC3-Ⅱ蛋白增加(P0.05),ERK1/2 mRNA变化差异无统计学意义(q值依次为2.63、2.65、2.83,P0.05),p-ERK1/2蛋白变化差异无统计学意义(P0.05)。结论 SAH后激活的ERK1/2激活,可促进Beclin-1和LC3-Ⅱ表达介导神经细胞丢失。