Genome-wide expression analysis of ischemic neuronal injury based on functional genomics and proteomics

短暂性脑缺血导致易感海马CA1区选择性和延迟性神经元死亡。多项研究表明，脑缺血可诱导多种基因的转录激活，尤其是与应激反应、细胞死亡或存活相关的基因，提示其与神经元缺血易感性密切相关。DNA微阵列技术的最新进展为在单个杂交实验中分析数千个基因的表达提供了工具。利用这些技术，利用包含8,799个探针的寡核苷酸DNA微阵列，在大鼠全身缺血模型中对海马CA1区域进行了延迟神经元死亡和诱导缺血耐受的全基因组基因表达分析。结果表明，246个转录本在缺血后表达水平升高，213个转录本表达水平降低，占所代表探针组的5.1%。使用分层聚类分析将这些变化分为七个表达簇，每个表达簇具有不同的条件和特定的时间模式。缺血耐受与转录因子（c-Fos, JunB Egr-1,-2,-4, NGFI-B）， Hsp70和MAP激酶级联相关基因（MKP-1）的短暂上调有关，这些基因与细胞存活有关。延迟神经元死亡表现出复杂的长期表达变化，如促凋亡基因（GADD 153、Smad2、Dral、Caspase-2和-3）的上调和与生存信号相关的基因（MKK2、PI4激酶、DAG/PKC信号通路）的下调，表明死亡和生存信号之间的不平衡。我们的研究在全基因组分析中提供了延迟神经元死亡和诱导缺血耐受之间的差异基因表达谱，有助于进一步了解脑缺血复杂的分子病理生理。

Transient cerebral ischemia causes selective and delayed neuronal death in the vulnerable hippocampal CA1 region. Various studies have provided evidence that cerebral ischemia induces transcriptional activation of a variety of genes, particularly those related to stress response, cell death or survival, suggesting a close relationship with neuronal ischemic vulnerability. Recent advances in DNA microarray technology have provided tools to analyze the expression of thousands of genes in a single hybridization experiment. Employing these techonogies, genome-wide gene expression analysis of the hippocampal CA1 region was conducted in a rat global ischemia model for delayed neuronal death and induced ischemic tolerance using an oligonucleotide-based DNA microarray containing 8,799 probes.The results showed that expression levels of 246 transcripts were increased and 213 were decreased following ischemia, corresponding to 5.1% of the represented probe sets. These changes were divided into seven expression clusters using hierarchical cluster analysis, each with distinct conditions and time-specific patterns. Ischemic tolerance was associated with transient up-regulation of transcription factors (c-Fos, JunB Egr-1,-2,-4, NGFI-B), Hsp70 and MAP kinase cascaderelated genes (MKP-1), which are implicated cell survival. Delayed neuronal death exhibited complex long-lasting changes of expression, such as up-regulation of proapoptotic genes (GADD 153, Smad2, Dral, Caspase-2 and -3) and downregulation of genes implicated in survival signaling (MKK2, and PI4 kinase, DAG/PKC signaling pathways), suggesting an imbalance between death and survival signals.Our study provides a differential gene expression profile between delayed neuronal death and induced ischemic tolerance in a genomewide analysis, and contributes to further understanding of the complex molecular pathophysiology in cerebral ischemia.