LKB1表达下调对培养海马神经元突触mEPSC的影响

目的研究离体培养的海马神经元LKB1表达下调对于神经元微小兴奋性突触后电流(mEP-SC)的影响。方法选用17d的胚胎大鼠培养海马神经元,分别用电穿孔的方法转染CAG-RE质粒和LKB1RNAi质粒,培养10~12d后进行电生理记录,选用全细胞膜片钳方式及自由记录模式,细胞外液加TTX阻断动作电位,加Bicucullin抑制GABA电流,记录神经元的mEPSC,比较2组神经元的mEPSC频率和幅度的差别。结果转染CAG-RE的神经元mEPSC幅度平均为25.6pA,频率平均为(5.21±0.25)Hz,是基线的99.8%;转染LKB1RNAi的神经元mEPSC幅度平均为35.1pA,频率平均为(5.79±0.27)Hz,是基线的127.1%;比较2组间频率、幅度变化,差别有显著性意义(P<0.05)。结论LKB1基因表达下调增强了培养海马神经元突触传递的效率。     

大鼠半胱氨酸蛋白水解酶-3基因真核表达质粒和RNA干扰质粒的构建及鉴定

目的 构建SD大鼠半胱氨酸蛋白水解酶(Caspase)-3的真核表达质粒和干扰质粒,探究干扰质粒对Caspase-3表达的干预效应。方法 从SD大鼠软骨终板细胞中获得模板cDNA并扩增,约834 bp。克隆至载体pEGFP-N1,获得重组质粒pEGFP-N1-Caspase-3。针对Caspase-3设计4对RNAi靶点序列,克隆至载体pcDNA6.2。成功构建pcDNA6.2-Caspase-3-1、pcDNA6.2-Caspase-3-2、pcDNA6.2-Caspase-3-3、pcDNA6.2-Caspase-3-4,构建对照质粒pcDNA6.2-miRNA。将5个干扰质粒分别与pEGFP-N1-Caspase-3(用量比为7:1)共转染至293T细胞,qPCR检测转染48h后对Caspase-3表达的干预效应。结果 通过菌落聚合酶链反应(PCR)、酶切及测序表明pEGFP-N1-Caspase-3和干扰质粒构建成功;共转293T细胞后,qPCR示pcDNA6.2-Caspase-3-2、pcDNA6.2-Caspase-3-3干预组的Caspase-3的表达高于对照组,分别为33％和8％,而pcDNA6.2-Caspase-3-1、pcDNA6.2-Caspase-3-4干预组的Caspase-3的表达与对照组比较明显减少,抑制效率分别为24％和67％ (P ＜0.05)。结论 成功构建了Caspase-3的表达质粒和干扰质粒,并证实pcDNA6.2-Caspase-3-4对Caspase-3的表达具有明显的抑制效应。     

利用RNAi沉默KIAA0280后对缺氧诱导大鼠神经元凋亡的影响

目的利用RNA干扰(RNAi)技术,观察脑缺血相关新蛋白KIAA0280被特异性沉默后对正常神经元和缺氧诱导神经元凋亡的影响。方法取新生大鼠培养至5~7 d的神经元,经由密闭容器引起缺氧诱导神经元凋亡模型。采用RNAi技术封闭KIAA0280的表达,观察该基因被封闭后对正常神经元的生长以及缺氧诱导神经元凋亡的作用和影响。结果脂质体转染KIAA0280基因特异性siRNA12、24 h后对正常细胞生长具有一定的影响;在此基础上缺氧4、8 h,发现RNAi组的神经元对缺氧诱导的神经元凋亡比对照组对缺氧更加敏感,更易受损伤。结论KIAA0280对正常神经元具有一定的作用,并且对缺氧诱导凋亡神经元具有一定的保护作用。     

Blockade of SDF-1/CXCR4 signalling inhibits pancreatic cancer progression in vitro via inactivation of canonical Wnt pathway

Extra-pancreatic metastasis is a difficult problem for surgical intervention in pancreatic cancer. CXC chemokine receptor 4 (CXCR4) was considered to have an important role in this process. We hypothesized it may contribute to the pancreatic cancer progression through influencing canonical Wnt pathway. The purpose of this study was to examine the functional role of CXCR4 in the progression of pancreatic cancers and explore the possible mechanism. To this end, the relation between CXCR4 and clinical characteristics was analysed. shRNA against CXCR4 was applied to disrupt the SDF-1/CXCR4 signal transduction pathways in pancreatic cancer cell lines. Our results showed that overall survival in the case of patients positive for CXCR4 expression was significantly lower than that in the case of patients negative for CXCR4 expression. Notably, in vitro studies we observed that the abrogation of CXCR4 could obviously influence the pancreatic cancer cell phenotype including cell proliferation, colony formation, cell invasion and also inhibit the TOPflash activity. In addition, Wnt target genes and mesenchymal markers such as Vimentin and Slug were also inhibited in CXCR4 knockdown cells. Collectively, these data reported here demonstrate CXCR4 could modulate the canonical Wnt pathway and perhaps be a promising therapeutic target for pancreatic cancer progression.     

慢病毒介导的Survivin基因稳定干扰PC-3细胞系的建立

目的：构建生存素（Survivin）基因稳定干扰的PC-3细胞系。方法：设计针对Survivin基因的shR—NA序列，构建Survivin shRNA慢病毒载体并感染PC-3细胞，采用RT-PCR和流式细胞技术分别检测Survivin mRNA和蛋白表达水平，并与阴性对照组和空白对照PC-3细胞进行比较。结果：Survivin shRNA慢病毒载体感染PC-3细胞后，Survivin mRNA和蛋白水平分别为（5．89±0．12）％和（11．82±0．32）％，明显低于阴性对照组（55．17±0．87）％、（95．70±1．56）％和空白对照PC-3细胞（58．21±0．68）％、（95．90±1．78）％。结论：采用shR—NA慢病毒载体成功构建了Survivin基因稳定干扰的PC-3细胞系。     

稳定转染CDK2干扰RNA的人肝癌HepG2细胞系的建立

目的建立稳定转染CDK2干扰RNA的人肝癌HepG2细胞系。方法用Lipofectamine^TM 2000法将已构建好的特异性的携带绿色荧光蛋白的CDK2干扰RNA的重组质粒P^Genesil-1-CDK2转染入HepG2细胞，经G418筛选后获得稳定转染细胞株，并用倒置荧光显微镜观察转染细胞的绿色荧光蛋白，利用逆转录-聚合酶链反应（RT-PCR）检测转染后的HepG2细胞CDK2 mRNA的表达。结果倒置荧光显微镜观察与KT-PCR检测，结果显示获得重组质粒P^Genesil-1-CDK2稳定转染的细胞克隆。结论建立了可稳定转染CDK2干扰RNA的人肝癌HepG2细胞系，为进一步研究细胞周期调控蛋白激酶对肝细胞癌的治疗与开发新的特异性药物提供了实验依据。     

Can we increase the speed and efficacy of antidepressant treatments? Part II. Glutamatergic and RNA interference strategies

In the second part we focus on two treatment strategies that may overcome the main limitations of current antidepressant drugs. First, we review the experimental and clinical evidence supporting the use of glutamatergic drugs as fast-acting antidepressants. Secondly, we review the involvement of microRNAs (miRNAs) in the pathophysiology of major depressive disorder (MDD) and the use of small RNAs (e.g.., small interfering RNAs or siRNAs) to knockdown genes in monoaminergic and non-monoaminergic neurons and induce antidepressant-like responses in experimental animals.The development of glutamatergic agents is a promising venue for antidepressant drug development, given the antidepressant properties of the non-competitive NMDA receptor antagonist ketamine. Its unique properties appear to result from the activation of AMPA receptors by a metabolite [(2 S,6 S;2 R,6 R)-hydroxynorketamine (HNK)] and mTOR signaling. These effects increase synaptogenesis in prefrontal cortical pyramidal neurons and enhance serotonergic neurotransmission via descending inputs to the raphe nuclei. This view is supported by the cancellation of ketamine's antidepressant-like effects by inhibition of serotonin synthesis.We also review existing evidence supporting the involvement of miRNAs in MDD and the preclinical use of RNA interference (RNAi) strategies to target genes involved in antidepressant response. Many miRNAs have been associated to MDD, some of which e.g., miR-135 targets genes involved in antidepressant actions. Likewise, SSRI-conjugated siRNA evokes faster and/or more effective antidepressant-like responses. Intranasal application of sertraline-conjugated siRNAs directed to 5-HT_1A receptors and SERT evoked much faster changes of pre- and postsynaptic antidepressant markers than those produced by fluoxetine.