A gene expression study of regional vulnerability in Alzheimer's disease

描述(由申请人提供)：神经退行性疾病的一个重要问题是区域性脆弱性问题。为什么在大多数潜在致病基因普遍表达的情况下，特定大脑区域的特定细胞类型首先成为靶点？在阿尔茨海默病(AD)的病例中，PSEN1、PSEN2和APP突变在大多数情况下会导致典型的神经变性模式，首先是CA1海马区锥体细胞的变性，然后是结构相似的CAS锥体神经元、后顶叶和顶上叶的变性，最后是大部分大脑皮层的变性，保留小脑和初级感觉皮质。散发性阿尔茨海默病，其特定的孟德尔突变尚未被识别，导致基本上相同的疾病进展。我们假设，对AD病理相对不敏感的区域表达提供相对保护的基因模式，而更脆弱区域的基因表达变化反映了它们的脆弱性。同样，神经退行性变的易感性不是在整个组织水平上发生，而是在特定类型的细胞中发生。因此，通过比较结构相似的神经元或海马区(CA1和CAS)中不同易受AD病理影响的基因表达，将揭示AD神经保护和易感性的靶点。在对照组和晚期AD患者中，使用激光捕获显微切割将从易受AD病理影响的CA1和相对较不脆弱的CAS中提取健康的锥体细胞。然后，从这些区域的细胞池中扩增出的cRNA将被杂交到定制的微阵列中，并使用标准方法分析差异表达基因。此外，每个区域特有的转录网络将使用加权基因共表达网络分析(WGCNA)来识别，这是一种揭示转录组织的强大新方法。总而言之，将在六种情况下收集表达数据：1)对照CA1、2)CAS和3)视杆，以及4)患病的CA1、5)CAS和6)视杆，其中视杆被包括为基本上不受AD影响的对照大脑区域。这些数据将被用来通过地区比较和控制/疾病比较来确定与AD的相对保护和易感性相关的转录网络。通过围绕寻找神经保护基因设计实验，该实验计划将发现AD的新靶基因，这可能有可能用于AD的早期诊断和治疗。

DESCRIPTION (provided by applicant): An important issue in neurodegenerative disorders is the issue of regional vulnerability. Why are specific cell types in specific brain regions targeted first, when most of the underlying disease-causing genes are expressed ubiquitously? In the case of Alzheimer's disease (AD), PSEN1, PSEN2, and APP mutations lead to a typical pattern of neurodegeneration in most cases, starting with degeneration of CA1 hippocampal pyramidal cells, followed later by degeneration of the structurally similar CAS pyramidal neurons, posterior, superior parietal lobe, and eventually by degeneration of most of the cerebral cortices, sparing cerebellum and primary sensory cortices. Sporadic AD, where specific Mendelian mutations have not been identified, leads to essentially the same disease progression. We hypothesize that regions relatively invulnerable to AD pathology express patterns of genes that provide relative protection, and that gene expression changes in more vulnerable regions reflect their vulnerability. Similarly, susceptibility to neurodegeneration does not occur on a whole tissue level, but rather in specific cell types. Therefore, by comparing gene expression in structurally similar neurons or regions of the hippocampus (CA1 and CAS) that are differentially vulnerable to AD pathology, targets for AD neuroprotection and susceptibility will be uncovered. Healthy pyramidal cells will be extracted from both CA1, which is vulnerable to AD pathology, and CAS, which is relatively less vulnerable, in both controls and individuals with advanced AD using laser capture microdissection. Amplified cRNA from pools of cells in these regions will then be hybridized to custom microarrays, and analyzed for differentially expressed genes using standard methods. Additionally, the transcriptional networks specific to each region will be identified using weighted gene co-expression network analysis (WGCNA), a powerful new method for uncovering transcriptomic organization. In all, expression data will be collected under six conditions: 1) Control CA1, 2) CAS, and 3) visual pole, as well as 4) diseased CA1, 5) CAS, and 6) visual pole, where visual pole is included as a control brain region that remains essentially unaffected by AD. These data will be used to determine the transcriptional network related to relative protection and susceptibility in AD through regional comparisons and control/disease comparisons. By designing our experiment around finding neuroprotective genes, this experimental plan will uncover novel target genes for AD, which may have the potential for early diagnoses and treatment of AD.