原代培养大鼠脊髓神经元损伤前后Fos、TH及PNMT表达变化的研究

为了探讨多巴胺及肾上腺素在神经元损伤和修复过程中的作用,我们通过锐器切割原代培养的纯化大鼠胚胎脊髓神经元,模拟脊髓全横断后脊髓神经元损伤状态,观察了损伤前后Fos蛋白与儿茶酚胺类神经递质合成酶的表达变化。分离、培养、纯化孕14d的Wistar大鼠脊髓神经元,10d后在直视下进行脊髓神经元的锐器切割损伤。用免疫组化及Western blot技术研究损伤前后神经元内Fos蛋白与酪氨酸羟化酶(TH)、苯乙醇胺氮位甲基移位酶(PNMT)的共定位情况及表达水平变化。结果发现:脊髓神经元损伤10min后Fos蛋白开始表达,2h后Fos阳性达到最高并同时表达TH及PNMT;Western blot结果也证实损伤后Fos、TH和PNMT表达均较损伤前上调。上述结果提示,神经元经损伤后激活的即刻早期基因c-fos,可作为信号分子活化受损神经元内儿茶酚胺类神经递质(TH和PNMT),多个分子共同作用可能参与了神经元的损伤和修复过程,其生物学意义有待进一步探讨。

翻译认知视角下的神经网络翻译研究——以Systran PNMT为例

基于人工神经网络技术的机器翻译技术,是目前世界上新兴的机器翻译技术,备受学界、业界乃至全球很多大型实体企业、组织机构的关注和青睐。本文对Systran PNMT(Pure Neural Machine Translation)的研究背景、翻译系统应用价值、翻译效果等方面进行了分析,进一步阐明与认知相结合的信息翻译技术对翻译实践的辅助作用,并基于翻译认知理论对神经网络翻译技术的进一步发展提出建议和展望。

鳖甲煎丸含药血清抑制肝癌细胞的miRNA-mRNA调控机制分析

目的探讨鳖甲煎丸干预肝癌细胞后miRNA/mRNA的表达变化和分子机制。方法 CCK-8法检测鳖甲煎丸含药血清干预肝癌细胞后的增殖活性变化,流式细胞术检测鳖甲煎丸含药血清对肝癌细胞细胞周期和凋亡率的影响,全细胞转录组学分析miRNA/mRNA表达变化,差异表达的miRNA和mRNA进行KEGG富集分析,构建miRNA-mRNA调控网络,通过荧光定量PCR和Western blot法验证PNMT和ST8SIA5表达。结果鳖甲煎丸含药血清可抑制肝癌细胞增殖活性,阻滞细胞生长于G_0/G_1期,还可促进细胞凋亡。全细胞转录组学分析找到差异表达的48个miRNA和168个mRNA。通过KEGG富集分析发现代谢通路是主要通路,PNMT和ST8SIA5是其调控的核心基因。鳖甲煎丸含药血清可抑制PNMT的表达和上调ST8SIA5的表达。结论 miRNA-mRNA调控网络是鳖甲煎丸抑制肝癌细胞增殖的分子机制,其中代谢通路是主要调控通路,PNMT和ST8SIA5是调控的核心基因。

Gene Regulation of Catecholamine Biosynthetic Enzymes by Nitric Oxide in PC12 Cells

Nitric oxide (NO) regulates a wide range of physiological processes. Recent studies show that NO can regulate the release of catecholamines (CA) from the adrenal medulla. In the current study, the PC12 cell line was used to examine the effect of NO on the regulation of the CA biosynthetic enzymes: tyrosine hydroxylase (TH), dopamine-β-hydroxylase (DBH) and phenylethanolamine Nmethyltransferase (PNMT). Treatment of PC12 cells with the NO donor, sodium nitroprusside (SNP) for 6 hours significantly increased TH, DBH and PNMT mRNA levels. In addition, NO potentiates the regulation of gene expression of all three CA biosynthetic enzymes by glucocorticoids and cholinergic agonists. The signaling pathways involved in NO regulation of CA biosynthetic enzymes were investigated with the use of specific kinase activators and inhibitors, with results supporting a contributing role of PKA, PKC and PKG in SNP-mediated induction for all three CA genes (p < 0.01). In addition, inhibitors of transcription and translation inhibited SNP-mediated induction of all three genes (p < 0.001) suggesting that both transcriptional and translational mechanisms may be involved in CA gene regulation by NO. Results from this study show that in addition to regulating CA biosynthetic enzymes, NO can also potentiate cholinergic and glucocorticoid activation of CA genes.

肾上腺嗜铬细胞的超微结构与多巴胺-β-羟化酶,苯乙胺-N-甲基转移酶的免疫细胞化学定位

以一般电镜技术,及用抗大鼠多巴胺-β-羟化酶(DβH)、苯乙胺-N-甲基转移酶(PNMT)血清作免疫细胞化学染色后,对大鼠、猫和豚鼠肾上腺嗜铬细胞进行电镜观察。结果显示:大鼠和猫嗜铬细胞,按所含颗粒的不同电子密度,可明显区分为肾上腺素细胞、去甲肾上腺素细胞和混合颗粒细胞。猫还有小颗粒嗜铬样细胞。DβH和PNMT阳性反应产物均定位于大鼠、豚鼠和猫嗜铬细胞的嗜铬颗粒内,颗粒形状有环形和致密两种。细胞基质和细胞器均无免疫反应产物沉着。