2/2-Measuring translational dynamics and the proteome to identify potential brain biomarkers for psychiatric disease

摘要 为了进一步确定双相情感障碍和精神分裂症的分子基础，我们建议研究 来自300名患者大脑的额叶皮层组织中全基因组水平的蛋白质翻译和丰度 健康的对照。我们已经从这些大脑中收集了大量的数据，包括 基因型、转录组谱和染色质状态。下一步是寻找蛋白质功能的改变， 同样的大脑，因为蛋白质是基因表达的最终产物，也是遗传之间的关键联系。 变异和更高级的表型，包括疾病诊断。因为蛋白质是由mRNA编码的 在转录本中，似乎蛋白质水平应该与转录本水平大致相关。然而，衡量 mRNA及其相应蛋白质的表达水平通常是不一致的，它们各自的表达水平图也是如此。 数量性状基因座由于我们无法解释这些差异， 潜在的精神疾病显然不完整 以前大多数基于人群的神经精神病学蛋白质研究仅限于候选蛋白质， 哪些抗体已经存在例如，在我们的PsychENCODE项目中，我们使用 microwestern阵列分析~1000蛋白质。在这项研究中，我们将使用最近开发的技术， 核糖体分析和下一代蛋白质组学，以确定哪些转录本在大脑中被积极翻译 并对超过12,000种蛋白质的丰度进行量化。通过综合数据分析， 补充技术，以检测翻译产物并测量它们的定量关系。 此外，将评估这些蛋白质及其翻译效率与疾病的相关性。到 为了进一步提高定量的特异性，我们将使用最先进的去卷积方法来定量细胞 类型的翻译效率和蛋白质产物的具体措施。这将允许蛋白质翻译， 丰富的特定主要脑细胞类型，以研究它们在受影响大脑中的变化。 这项研究是创新的，因为它是第一个全基因组，基于人群的蛋白质翻译研究， 在精神病患者的大脑中大量存在。它提供了一个独特的机会，以填补转录组之间的差距， 蛋白质组数据，以及遗传变异和高阶表型之间的关系。这将是一个巨大的进步， 研究人类大脑的蛋白质和与精神疾病相关的调节变化， 最终会导致更好的诊断和治疗这些疾病。

Abstract To further our efforts in identifying the molecular bases of bipolar disorder and schizophrenia, we propose to study protein translation and abundances at the genome-wide level in frontal cortex tissue from 300 brains from patients and healthy controls. We have already amassed an enormous amount of data from these brains, including genotypes, transcriptome profiles and chromatin states. The next step is to look for alterations in protein function in the same brains, since proteins are the ultimate products of gene expression and a critical link between genetic variants and higher order phenotypes, including disease diagnosis. Since proteins are encoded by mRNA transcripts, it appears that protein levels should roughly correlate with transcript levels. However, measured expression levels of mRNAs and their corresponding proteins are often discordant, as are maps of their respective quantitative trait loci. Since we are unable to explain these discrepancies, our picture of molecular changes underlying psychiatric disorders is clearly incomplete. Most previous population-based studies of proteins in neuropsychiatry have been limited to candidate proteins, for which antibodies are already available. For example, in our PsychENCODE project, we are the process of using microwestern arrays to assay ~1000 proteins. In this study, we will use the recently developed technique of ribosome profiling and next-generation proteomics to identify which transcripts are actively being translated in brain and to quantify the abundance of more than 12,000 proteins. Through integrative data analysis, we use the two complementary technologies to detect translational products and to measure their quantitative relationships. Furthermore, these proteins and their translation efficiencies will be assessed for association with disorders. To further improve the specificity of quantification, we will use state-of-the-art deconvolution methods to quantify cell type specific measures of translation efficiency and protein products. This will allow protein translation and abundance in specific major brain cell types to be studied for their changes in affected brains. This study is innovative for being the first genome-wide, population-based study of protein translation and abundance in brains of psychiatric patients. It offers a unique opportunity to fill the gaps between transcriptome and proteome data, and between genetic variants and higher-order phenotypes. It will be a huge step forward in studying the proteins of human brains and the regulatory changes associated with psychiatric disorders, which should ultimately lead to better diagnosis and treatment of these diseases.