β淀粉样蛋白和α1-抗糜蛋白酶对星形胶质细胞激活的作用

Microarray analysis of human primary astrocytes activated by β amyloid peptide and α1- antichyraotrypsin

目的研究星形胶质细胞在β淀粉样蛋白1-42（Aβ1-42）和α1-抗糜蛋白酶（ACT）作用下的基因表达变化，探索AD脑组织中胶质细胞炎症反应的特征。方法人原代星形胶质细胞培养至第二代后，分别加入脂多糖（LPS）、Aβ1-42（50μmol／L）或Aβ1-42／ACT（50：5μmol／L）复合物，24h后提取总RNA。用基因芯片方法检测胶质细胞的基因表达谱，并分析差异表达基因在功能和信号传导通路方面的关系。结果Aβ1-42和Aβ1-42／ACT对胶质细胞基因表达的影响较LPS广泛，以上调作用为主；且各组间基因表达的变化明显不同。Gene Ontology分析显示Aβ1-42使炎症应激反应、免疫调节相关基因表达增加；而Aβ1-42／ACT对线粒体损害和细胞凋亡、氧化应激反应、上皮分化和脉管发生等相关基因都有显著影响。以Aβ1-42、Aβ1-42／ACT实验组中表达上调的白介素6（IL-6）、肿瘤坏死因子α（TNFα）等关键基因进行相关信号传导通路分析显示下游转录因子和基因可进一步诱导炎症因子生成、细胞凋亡并影响Aβ的产生。结论基因芯片研究证实Aβ1-42可诱导胶质细胞的炎症反应，与ACT结合后产生不同的作用，提示Aβ1-42、ACT都是参与AD病理过程的重要物质。Aβ1-42诱导胶质细胞产生的IL-6、TNFα及其信号传导通路在介导AD的发病中发挥重要作用。

Objective To investigate gene expression of astrocytes under the actions of amyloid peptide Aβ1-42 and α1-antichymotrypsin （ACT） and to explore the characteristics of inflammatory reactions occurring in brain of Alzheimer＇s patients. Methods Human primary astrocytes were cultured to the second passage and then treated with lipopolysaccharide （LPS）, Aβ1-42 （50 μmol/L） and Aβ1-42/ACT （50：5μmol/L） respectively. At 24 h, ceils were harvested for total RNA extraction. Gene expression profile was screened by microarray technique. And the function ,enrichment of differentially expressed genes and the signal transduction pathways involved were analyzed. Results In comparison with LPS, both Aβ1-42 and Aβ1-42/ACT had demonstrated marked effects on altering the astrocyte gene expression. And the gene up- regulation was predominant. But the gene expression spectrum varied between different groups. Gene ontology analysis showed thatAβ1-42 up-regulated genes modulated inflammation, oxidative stress and immune response. But Aβ1-42/ACT had significant effects on genes related with mitochondrial impairment, apoptosis, oxidative stress, epithelial differentiation and vasculogenesis. The analysis of up-regulated genes, such as interleukin 6 （IL-6） and tumor necrosis factor α（TNFα）, showed that transcriptional factors and downstream genes of signal transduction pathways potentiated further the inflammatory response and cell apoptosis and increased the production of abnormal Aβ. Conclusion Aβ1-42 induces the inflammation of astrocytes. And the Aβ1-42/ACT complex has diverse effects on the gene expression of astrocytes. Thus both proteins play important roles in the activation of astrocytes. In addition, IL-6, TNFα and their signal pathways are important in the pathogenic process of Alzheimer＇s disease.