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1.
Cdk4/cyclin D1通路异常参与C型Niemann-Pic病小鼠神经元变性   总被引:2,自引:0,他引:2  
以Balb/cnihnpc-1小鼠模型为对象,使用免疫组织化学和免疫印迹技术来研究cdk4/cyclin D1/Rb2通路的激活与神经元神经丝蛋白的过度磷酸化及神经元变性的相互关系,探讨C型Niemann-Pick病(NPC)病理性球状神经轴突形成的机制。实验表明,cdk4/cyclin D1在该小鼠模型脑白质球状神经轴突中异常聚集,其下游因子Rb2/p130呈现过度磷酸化并分布在上述病理性结构中。它们的分布随鼠龄增加而逐渐从脑干扩大到其他脑白质区域。球状神经轴突的主要成分之一为过度磷酸化神经丝蛋白,它与cdk4的分布在时空中具有高度的一致性。提示cdk4/cyclin D1/Rb2通路激活参与NPC神经元球状神经轴突形成,并与神经丝蛋白的异常磷酸化关系密切。该通路可作为干预神经元变性的一个新的靶点来挽救病损的神经元。  相似文献   

2.
细胞周期依赖性蛋白激酶5(cyclin-dependent kinase5,Cdk-5)及蛋白激酶A(protein kinaseA,PKA)是调节Tau蛋白磷酸化的重要激酶,其对糖尿病(diabetes mellitus,DM)大鼠脑内Tau蛋白磷酸化的作用如何,目前尚不明确.为探讨胰岛素缺乏的DM大鼠海马Cdk-5及PKA对Tau蛋白磷酸化的作用,用链脲佐菌素(streptozotocin,STZ)建立DM大鼠模型,Fura-2负载及荧光测定细胞内游离Ca2 浓度,免疫沉淀法测定Cdk-5活性,放射性配体结合实验检测PKA的活性,蛋白质印迹检测Tau蛋白磷酸化的水平.结果提示:在DM大鼠海马神经元,Ca2 浓度升高,Cdk-5及PKA活性升高,Tau蛋白在Ser198/Ser199/Ser202和Ser396/Ser404位点的磷酸化增强.Cdk-5的特异性抑制剂roscovitine可降低DM大鼠Cdk-5活性,但不能降低PKA活性,使Tau蛋白在Ser198/Ser199/Ser202位点磷酸化水平降低,但不降低Ser396/Ser404位点的磷酸化,roscovitine处理正常大鼠后,上述酶的活性及Tau蛋白的磷酸化无明显变化.首次从整体水平上证实DM大鼠海马Cdk-5及PKA活性升高,协同促进Tau蛋白在Ser198/Ser199/Ser202位点和Ser396/Ser404位点的磷酸化,神经元内游离Ca2 浓度升高可能起重要作用.  相似文献   

3.
目的 观察局灶性脑缺血后海马和缺血边缘区星形胶质细胞过度增殖对微循环的影响。方法将大鼠随机分为假手术组、缺血组和干预组,缺血组和干预组采用线栓法制备大脑中动脉栓塞模型,缺血组侧脑室采用ALZET微渗透泵给予0.2%DMSO,干预组给予细胞周期抑制剂roscovitine,假手术组不插入线栓,不给与任何药物干预。缺血7d后于股静脉注入FITC标记的葡聚糖标记血管,小鼠抗大鼠单克隆抗胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)抗体标记星形胶质细胞;激光共聚焦三维成像显示胶质细胞于微循环之间的关系。结果缺血同侧海马和缺血边缘区在GFAP阳性细胞增多的同时,局部微血管血流灌注明显减少,应用细胞周期抑制剂roscovitine抑制星形胶质细胞增生可以明显增加局部微血管的血流灌注。结论脑缺血后缺血边缘区和海马的反应性星形胶质细胞增生与微循环灌注减少密切相关。  相似文献   

4.
p27蛋白是周期蛋白依赖性激酶抑制剂家族的一员,通过抑制周期蛋白-周期蛋白依赖性激酶(cyclin-CDK)复合物活性对细胞周期进行负性调节,使细胞周期停滞在G1期。p27基因表达异常与多种恶性肿瘤的发生发展及预后有关。在p27基因发挥作用过程中,有众多的因素参与调控。本文简要介绍p27基因的结构与功能、表达调控以及与恶性肿瘤关系的研究进展。  相似文献   

5.
目的: 评估二肽基肽酶4(DPP-4)抑制剂利格列汀对小鼠脑缺血/再灌注(I/R)损伤的神经保护作用。方法: BALB/c小鼠随机分为Sham组、I/R组和利格列汀(2.5、5和10 mg/kg) +I/R组,每组均为8只小鼠。不同剂量利格列汀组小鼠均在I/R前3周连续灌胃给药。采用小鼠脑中动脉闭塞(MCAO)1 h诱导I/R损伤模型,再灌注24 h评估神经功能缺损(n=8)和及梗死体积(n=4);再灌注48 h处死小鼠,检测脑组织中谷胱甘肽(GSH)、丙二醛(MDA)、磷酸化肌醇3激酶(PI3K)、磷酸化蛋白激酶 B(p-Akt)和雷帕霉素靶蛋白(mTOR)含量(n=4)。结果: 与I/R组相比,利他列汀预处理组小鼠再灌注24 h后,神经功能缺损评分和梗死体积明显降低(P<0.05);小鼠再灌注48 h后,脑内MDA含量明显降低(P<0.05),而GSH、PI3K、p-Akt和mTOR水平明显升高(P<0.05)。结论: 利格列汀对I/R小鼠具有神经保护作用,可能是通过激活PI3K/AKT/mTOR通路发挥的作用。  相似文献   

6.
吲哚丁酸通过蛋白磷酸化激活湖北海棠根系Ca2+-ATP酶   总被引:3,自引:2,他引:1  
以湖北海棠(Malus hupehensis Rhed.)实生苗为试材,通过在砂培液中加入吲哚丁酸(IBA)和蛋白激酶抑制剂3,3’,4’,5,7-五羟黄酮(quercetin)研究了IBA对根系膜蛋白磷酸化和Ca2 -ATPase活性的影响.试验表明根系膜蛋白磷酸化反应主要发生在丝氨酸残基上100 μmol/L的IBA使蛋白激酶和Ca2 -ATPase活性在2~3h内升高数十倍,之后很快下降,蛋白激酶活性变化明显早于Ca2 -ATPase;蛋白激酶抑制剂quercetin不仅抑制根系膜蛋白的磷酸化,也显著削弱IBA对Ca2 -ATPase的激活作用.结果显示,在对IBA响应中Caa2 -ATPase是信号转导途径中的成员,IBA可能通过蛋白磷酸化激活根系Ca2 -ATPase而起作用.  相似文献   

7.
抑制大鼠褪黑素的合成对神经细丝过度磷酸化的影响   总被引:1,自引:0,他引:1  
目的探讨抑制褪黑素的生物合成对大鼠海马神经细丝过度磷酸化的影响及其可能机制.方法侧脑室注射氟哌啶醇并腹腔注射加强,HPLC检测血清中褪黑素水平;利用免疫组化检测大鼠海马区域神经细丝磷酸化情况;微量测定法测定超氧化物歧化酶(SOD)活性和脂质过氧化产物丙二醛的含量.结果①模型组大鼠血清中褪黑素的含量明显下降.②海马区域神经细丝发生聚集和异常过度磷酸化,补充不同剂量的褪黑素的治疗组较模型组的磷酸化程度有所改善.③模型组SOD活性降低,丙二醛(MDA)含量明显升高.结论褪黑素水平的降低引起AD-样神经细丝异常过度磷酸化,外源性补充褪黑素可以一定程度上减轻神经细丝的异常过度磷酸化.  相似文献   

8.
Alzheimer病(AD)中, 异常过度磷酸化的tau蛋白会导致细胞骨架的异常并与神经元的死亡有关. 在体外, 细胞周期蛋白依赖性蛋白激酶5(cdk-5)能在大多数AD相关位点磷酸化tau蛋白. 旨在整体水平研究cdk-5过度表达对大鼠微管相关蛋白 tau的磷酸化及空间记忆的影响. 结果显示, 在大鼠海马区转染cdk-5基因, 24 h后其局部表达增加, 并使得抗体tau-1显色减弱, PHF-1和12e8显色增强, 提示tau蛋白在Ser199/202, Ser396/404和Ser262/356位点过度磷酸化. 此外, 在水迷宫测试中, cdk-5转染鼠寻找安全平台所需时间比对照鼠明显延长, 而转染后48 h cdk-5的表达较24 h时下降, 同时伴有tau蛋白磷酸化程度的下降和空间记忆能力的改善. 这些结果提示整体水平的cdk-5的过度表达会导致大鼠的空间记忆损伤, 而过度磷酸化的tau蛋白可能参与了该病理过程.  相似文献   

9.
本研究旨在阐明猪miR-331-3p对细胞增殖的影响,探讨其对细胞增殖的作用机制首先构建了miR-331-3p的过表达载体pcDNA 3.1 (+)-miR-331-3p,并将将PK15细胞分为4组,分别为实验组、实验组对照组、抑制剂组和抑制剂对照组。实验组和对照组分别转染pcDNA 3.1(+)-miR-331-3p和pcDNA 3.1(+)。抑制剂组和抑制剂对照组分别转染miR-331-3p Inhibitor和miR-331-3p阴性对照(miR-331-3p NC)。通过在各组添加CCK-8试剂绘制细胞增殖曲线,并使用PI染色检测细胞所处周期比例。同时,利用实时荧光定量PCR(Quantitative real-time PCR,qPCR)检测生长抑制蛋白家族成员5 (Inhibitor of growth family member 5,ING5)、细胞周期蛋白依赖性激酶2 (Cyclin dependent kinase 2,CDK2)、细胞周期蛋白依赖性激酶3 (Cyclin dependent kinase 3,CDK3)、细胞周期蛋白依赖性激酶4 (Cyclin dependent kinase 4,CDK4)、细胞周期蛋白B (Cyclin B)和细胞周期蛋白依赖性激酶抑制剂1A(Cyclindependentkinaseinhibitor1A,CDKN1A)的表达变化。结果表明,实验组miR-331-3p表达量显著升高,细胞增殖曲线表明48 h和72 h时细胞数目均呈现出实验组实验对照组和抑制剂对照组抑制剂组的趋势(P0.05)。与实验对照组相比,实验组处于G0/G1期的细胞比例下调,S期和G2/M细胞的比例上调,抑制剂对照组趋势与之相反;同时,实验组中与促进增殖的基因CDK2、CDK3、CDK4和CyclinB的mRNA表达水平均显著升高,而抑制增殖的基因ING5和CDKN1A均表现出显著下降的趋势。本研究成功构建了miR-331-3p过表达载体,且发现miR-331-3p具有促进猪肾上皮细胞增殖的能力,研究结果为深入研究miR-331-3p在猪生长发育中的作用机制奠定了基础。  相似文献   

10.
为探讨兴奋性神经传递系统是否参与冷水应激引起的tau蛋白磷酸化,将小鼠于4℃冷水应激5min.采用免疫印迹和免疫组织化学方法分析应激后脑内c-fos和磷酸化tau蛋白的表达情况;运用HPLC检测冷水应激后小鼠脑内兴奋性或抑制性神经递质的变化;同时分析兴奋性氨基酸受体和L-型钙通道拮抗剂预处理后冷水应激小鼠脑内磷酸化tau蛋白的水平.冷水应激后1h,海马内磷酸化tau蛋白的水平显著升高,同时伴c-fos的染色增加.HPLC检测显示,兴奋性和抑制性神经递质呈现急剧上升而后又下降的趋势.冷水应激后15min,天冬氨酸和甘氨酸水平显著升高,1h后天冬氨酸、谷氨酸、牛磺酸和γ-氨基丁酸显著下降.NMDA受体拮抗剂MK-801(5mg/kg)和AMPA受体拮抗剂DNQX(0.5,5mg/kg)可显著抑制冷水应激引起的磷酸化tau蛋白水平的升高,代谢性谷氨酸受体拮抗剂MAP-4不影响tau蛋白的磷酸化,另外,L-型钙通道阻断剂尼莫地平可抑制冷水应激引起的磷酸化tau蛋白水平的升高.这些结果表明,冷水应激可影响兴奋性神经传递系统,通过离子型兴奋性氨基酸受体和异常神经激活来调节tau蛋白的磷酸化.兴奋性神经传递系统的激活在冷水...  相似文献   

11.
Hyperphosphorylation of neurofilament and tau, and formation of cytoskeletal lesions, are notable features of several human neurodegenerative diseases, including Niemann-Pick Disease Type C (NPC). Previous studies suggested that the MAPKs, extracellular signal regulated kinase 1 and 2 (ERK1/2) may play a significant role in this aspect of NPC. To test this idea, we treated npc mice with PD98059, a specific and potent inhibitor of MAPK activation. Although activity of ERK1/2 was inhibited by 40%, a 2-week intracerebroventricular infusion of PD98059 just prior to onset of cytoskeletal pathology and symptoms in npc mice did not delay or inhibit prominent hallmarks of NPC. Unexpectedly, ERK1/2 inhibition led to aggravation of tau hyperphosphorylation, particularly in oligodendroctyes, in a manner similar to that of certain human tauopathies. Our results suggest that ERK1/2 does not play a major role in NPC neuropathology, and therefore, that MAPK inhibition is unlikely to be a useful strategy for managing the disease.  相似文献   

12.
In all systems examined so far, the G2/M phase transition is controlled by the M-phase promoting factor (MPF), a complex of cdc2 (CDK1) and cyclin B1. Histone H1 kinase activity and MPF components are present in pachytene spermatocytes (PS). However, it has not been demonstrated yet that direct inhibition of MPF activity prevents the G2/M transition in these cells. When roscovitine, a potent inhibitor of CDK1, CDK2, and CDK5 activities, was added to cocultures of PS with Sertoli cells, the number of both secondary spermatocytes and round spermatids formed were lower than in control cultures, despite similar cell viability. This effect of roscovitine was reversible, did not involve the Sertoli cells, and was dependent on the concentration of the inhibitor. Roscovitine did not modify the amount of MPF in these germ cells but inhibited the CDK1- or CDK2-associated histone H1 kinase activity of PS. Hence a functional relationship between cyclin-dependent kinase activity and the spontaneous processing of the first meiotic division and, for the first time, of the second meiotic division of male germ cells is shown.  相似文献   

13.
Caspase-3在roscovitine诱发PC12细胞凋亡中发挥重要作用   总被引:6,自引:0,他引:6  
Gao JX  Zhou YQ  Zhang RH  Ma XL  Liu KJ 《生理学报》2005,57(6):755-760
我们已证实周期蛋白激酶(cyclin-dependent kinases)cdk2、cdc2和cdk5抑制剂roscovitine诱导PC12细胞凋亡。本实验应用caspase-3免疫细胞化学与hoechst 33342荧光化学双标、MTT比色法细胞活性测定和Western blot方法,研究了caspase-3在roscovitine所致PC12细胞凋亡中的作用。结果显示,roscovitine(50μmol/L)处理PC12细胞12h,细胞核染色质凝缩及核碎片形成,同时胞浆中出现caspase-3阳性标志,caspase-3阳性细胞占细胞总数的42%。非特异性caspases抑制剂Z-VAD-FMK(50μmol/L)和caspase-3特异性抑制剂Z-DEVD-FMK(100μmol/L)可部分降低roscovitine所致的细胞死亡,使细胞存活率分别由29.03%(roscovitine)增至58.06%(Z-VAD-FMK+roscovitine)和45.16%(Z-DEVD-FMK+roscovitine):用单克隆non-erythroid α-spectrin抗体检测roscovitine处理组细胞匀浆提取液,表明caspase-3裂解的特异性spectfin 120kDa蛋白产物较对照组显著增加。提示细胞凋亡成分caspases参与roscovitine所敛的细胞凋亡,其中caspase-3发挥重要作用。  相似文献   

14.
Elastase-mediated cleavage of cyclin E generates low molecular weight cyclin E (LMW-E) isoforms exhibiting enhanced CDK2-associated kinase activity and resistance to inhibition by CDK inhibitors p21 and p27. Approximately 27% of breast cancers express high LMW-E protein levels, which significantly correlates with poor survival. The objective of this study was to identify the signaling pathway(s) deregulated by LMW-E expression in breast cancer patients and to identify pharmaceutical agents to effectively target this pathway. Ectopic LMW-E expression in nontumorigenic human mammary epithelial cells (hMECs) was sufficient to generate xenografts with greater tumorigenic potential than full-length cyclin E, and the tumorigenicity was augmented by in vivo passaging. However, cyclin E mutants unable to interact with CDK2 protected hMECs from tumor development. When hMECs were cultured on Matrigel, LMW-E mediated aberrant acinar morphogenesis, including enlargement of acinar structures and formation of multi-acinar complexes, as denoted by reduced BIM and elevated Ki67 expression. Similarly, inducible expression of LMW-E in transgenic mice generated hyper-proliferative terminal end buds resulting in enhanced mammary tumor development. Reverse-phase protein array assay of 276 breast tumor patient samples and cells cultured on monolayer and in three-dimensional Matrigel demonstrated that, in terms of protein expression profile, hMECs cultured in Matrigel more closely resembled patient tissues than did cells cultured on monolayer. Additionally, the b-Raf-ERK1/2-mTOR pathway was activated in LMW-E-expressing patient samples, and activation of this pathway was associated with poor disease-specific survival. Combination treatment using roscovitine (CDK inhibitor) plus either rapamycin (mTOR inhibitor) or sorafenib (a pan kinase inhibitor targeting b-Raf) effectively prevented aberrant acinar formation in LMW-E-expressing cells by inducing G1/S cell cycle arrest. LMW-E requires CDK2-associated kinase activity to induce mammary tumor formation by disrupting acinar development. The b-Raf-ERK1/2-mTOR signaling pathway is aberrantly activated in breast cancer and can be suppressed by combination treatment with roscovitine plus either rapamycin or sorafenib.  相似文献   

15.
16.
Although the developmental programs of plants and animals differ, key regulatory components of their cell cycle have been conserved. Particular attention has been paid to the role of the complexes between highly conserved cyclin and cyclin-dependent kinases in regulating progression through the cell cycle. The recent demonstration that roscovitine is a potent and selective inhibitor of the animal cyclin-dependent kinases cdc2 (CDK1), CDK2 and CDK5 prompted an investigation into its effects on progression through the plant cell cycle. Roscovitine induced arrests both in late G1 and late G2 phase in BY-2 tobacco cell suspensions. Both blocks were fully reversible when roscovitine was used at concentrations similar to those used in the animal system. Stationary-phase cells subcultured in the presence of roscovitine were arrested at a 2C DNA content. This arrest was more efficient without exogenous addition of plant growth regulator. Roscovitine induced a block in G1 earlier than that induced by aphidicolin. S-phase synchronized cells treated with roscovitine were arrested at a 4C DNA content at the G2/ M transition. The expression analysis of a mitotic cyclin (NTCYC1) indicated that the roscovitine-induced G2 block probably occurs in late G2. Finally, cells in metaphase were insensitive to roscovitine. The purified CDK/cyclin kinase activities of late G1 and early M arrested cells were inhibited in vitro by roscovitine. The implications of these experimental observations for the requirement for CDK activity during progression through the plant cell cycle are discussed.  相似文献   

17.
目的:探讨细胞周期蛋白依赖激酶(CDK)抑制剂Roscovitine(Ros)诱导非小细胞肺癌(NSCLC)A549细胞凋亡及其作用机制。方法:以不同浓度Ros(10μM、20μM、40μM)处理细胞24h,采用Annexin V-PI染色以流式细胞仪检测细胞凋亡,Westernblot法检测胞浆中和线粒体促凋亡蛋白Bax和Bad的表达,流式细胞仪检测线粒体膜电位(MMP)变化。结果:Ros以剂量依赖的方式诱导A549细胞凋亡,同时Bad和Bax在胞浆的含量随着Ros剂量的增加而减少,而在线粒体中却出现相反的结果,线粒体膜电位随Ros剂量的增大而降低。结论:Ros可通过促进Bax和Bad由胞浆向线粒体易位,诱导NSCLC A549细胞由线粒体途径发生凋亡。  相似文献   

18.
The Niemann-Pick C1 (NPC1) protein regulates cholesterol transport from late endosomes-lysosomes to other intracellular compartments. In this article, cholesterol transport to caveolin-1 and caveolin-2 containing compartments, such as the trans-Golgi network (TGN) and plasma membrane caveolae, was examined in normal (NPC+/+), NPC heterozygous (NPC+/-), and NPC homozygous (NPC-/-) human fibroblasts. The expression and distribution of NPC1 in each cell type were similar, and characterized by a finely dispersed, granular staining pattern. The expression of caveolin-1 and caveolin-2 was increased in NPC+/- and NPC-/- fibroblasts, although the distribution in each cell type was similar and characterized by predominant staining of the TGN and plasma membrane. The TGN in NPC+/+ fibroblasts was relatively cholesterol-enriched, whereas the TGN in NPC+/- and NPC-/- fibroblasts was partially or completely cholesterol-deficient, respectively. Consistent with studies demonstrating the transport of cholesterol from the TGN to plasma membrane caveolae, the concentration of cholesterol in plasma membrane caveolae isolated from NPC+/- and NPC-/- fibroblasts was significantly decreased, even though the total concentration of plasma membrane cholesterol in each cell type was similar.These studies demonstrate that NPC1 regulates cholesterol transport to caveolin-1 and caveolin-2 containing compartments such as the TGN and plasma membrane caveolae.  相似文献   

19.
Roscovitine, a specific inhibitor of MPF kinase activity, has been shown to block efficiently and reversibly the meiotic resumption of oocytes from different species, including cattle. In view to verify that oocytes maintain germinal vesicle like molecular activities under roscovitine treatment, we compared in the present study the M-phase Promoting Factor (MPF) and Mitogen Activated Protein (MAP) kinase activities; protein synthesis and phosphorylation patterns in oocytes and cumulus cells; and CDK1 and Cyclin B messengers storage under control culture and under roscovitine inhibition. We observed that roscovitine induced a full and reversible inhibition of MPF kinase activity and of the activating phosphorylation of both ERK1/2 MAPK. During in vivo maturation, there was a highly significant increase in the relative mRNA level of both cyclin B1 and CDK1 whereas during in vitro culture, the relative amount of CDK1 messenger was reduced. These messengers may be used as markers for the optimization of in vitro maturation treatment. Roscovitine reversibly prevented this drop in relative quantities of CDK1 messenger. Oocytes cultured in the presence of roscovitine maintained a GV like profile of protein synthesis except that two proteins of 48 and 64 kDa specific of matured oocytes also appeared under roscovitine treatment. However, roscovitine did not prevent most of the modifications of protein phosphorylation pattern observed during maturation. In conclusion, results of this study revealed that the use of roscovitine did not prevent all the events related to maturation of bovine oocytes.  相似文献   

20.
In carcinogenesis, inflammasomes may play contradictory roles through facilitating anti-tumor immunity or inducing oncogenic factors. Their function in cancer remains poorly characterized. In this study, we explored the effect of interleukin-17A (IL-17A) on the migration and invasion activity of nasopharyngeal carcinoma (NPC) cell lines and account for related mechanisms. Our results revealed that exogenous IL-17A promoted cell migration and invasion significantly in both NPC-039 and CNE-2Z cell lines. In addition, the expression of matrix metalloproteinase-2 (MMP-2)/-9 and Vimentin could be elevated by IL-17A stimulation; meanwhile the expression of E-cadherin was decreased. The results also show that IL-17A could activate the p38 signaling pathway in IL-17A-stimulated NPC-039 and CNE-2Z cell lines. Combining treatment with a p38 inhibitor (SB203580) resulted in decreased invasion capabilities of NPC-039 and CNE-2Z cell lines. SB203580 also inhibited the expression of MMP-2/-9 and increased the expression of E-cadherin in IL-17A-stimulated NPC-039 and CNE-2Z cell lines. IL-17A also could activate NF-κB in NPC-039 and CNE-2Z cell lines. In summary, our data show that IL-17A promote the cell migration and invasion of NPC cells. The effect of IL-17A on cell migration and invasion may be mediated via regulation of the expression of MMP-2/-9 and epithelial-mesenchymal transition (EMT) via p38-NF-κB signaling pathway. Thus, IL-17A or its related signaling pathways may be a promising target for preventing and inhibiting NPC metastasis.  相似文献   

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