MicroRNA Mapping in Major Depression

描述(申请人提供)：MDD是影响全球数百万人的最严重和最令人衰弱的疾病之一。尽管在过去的几十年里取得了长足的进步，但对MDD的病因仍缺乏明确的了解。越来越多的证据表明，MDD可能源于细胞级联反应的损伤，这导致调节情绪、认知和神经营养功能的回路中的异常信息处理。近年来，microRNAs(MiRNAs)已成为一类重要的非编码小RNA，通过与mRNAs的3‘端非编码区结合，抑制特定信使核糖核酸靶标的翻译和/或稳定性。由于miRNAs表现出高度调控的表达，它们有助于特定转录组的发育和维持，因此具有影响生理和疾病表型的独特能力。我们最近的研究表明，在MDD患者的PFC中，一组miRNAs的表达发生了变化，这些miRNAs参与了应对压力的反应。此外，越来越多的证据表明miRNAs参与了神经可塑性。这些研究表明，miRNAs很有可能在MDD的发病机制中起着重要作用。我们假设，在协调调控的情况下，miRNAs及其变体的亚群将在MDD脑中显示差异共表达，这将通过影响特定的神经/突触mRNA靶点和细胞通路，参与MDD的发病。在从MDD和对照组获得的特征良好的死后脑标本中，我们建议：1)通过小RNA测序来分析miRNA的表达，识别新的miRNAs，并分析差异表达的miRNAs；2)通过RNA测序来分析mRNAs的表达，并通过定位共表达网络模块来确定mRNAs和miRNA之间的调控关系；3)分析miRNA-mRNA对，通过实验验证改变的miRNAs和特定的靶基因，并在细胞水平上定位这些变化；4)分析MDD中与差异共表达模块相关的通路；5)通过确定pri-/Pre-miRNAs、RISC复合体和生物发生机制的组件来研究miRNA的生物发生；6)通过对突触体内的小RNA测序确定miRNA的丰度，分析突触部分特异改变的miRNA-mRNA的靶基因和共表达模块，以及在突触水平上检测miRNA生物发生机制的原/前miRNAs和组件，以探讨突触miRNAs在MDD发病机制中的作用。通过结合使用最先进的高通量小分子核糖核酸和核糖核酸测序，利用新的生物信息学工具分析数据和验证，识别特定细胞类型(S)中miRNAs及其靶点的变化，并研究miRNAs在突触水平上与情绪和认知相关的大脑区域中的作用，我们拟议的研究在分子水平上推进MDD研究领域具有独特的地位。这些研究将为将miRNAs开发为“分子工具”提供新的途径，有可能产生新的基于分子的治疗方法来治疗这种毁灭性的疾病。

DESCRIPTION (provided by applicant): MDD is one of the most severe and debilitating illnesses that affects millions of individuals worldwide. Despite considerable advances over the past decades, a clear understanding of the etiology of MDD is still lacking. Accumulating evidence suggests that MDD may arise from impairments in cellular cascades, which lead to aberrant information processing in the circuits that regulate mood, cognition, and neurovegetative functions. Recently, microRNAs (miRNAs) have emerged as an important class of small non-coding RNAs that by binding to 3' UTR of mRNAs, suppress the translation and/or stability of specific mRNA targets. Since miRNAs show a highly regulated expression, they contribute in the development and maintenance of a specific transcriptome and thus have the unique ability to influence physiological and disease phenotypes. Our recent studies show that the expression of a group of miRNAs is altered in PFC of MDD subjects and that they are involved in coping response to stress. In addition, accumulative evidence points to the involvement of miRNAs in neural plasticity. These studies suggest a strong possibility that miRNAs may contribute significantly to the etiopathogenesis of MDD. We hypothesize that subsets of miRNAs and their variants, regulated in a coordinated fashion, will show differential co-expression in MDD brain, which by affecting specific neural/synaptic mRNA targets and cellular pathways, will participate in MDD pathogenesis. In well characterized postmortem brain samples obtained from MDD and control subjects, we propose to: 1) profile miRNA expression by small RNA sequencing, identify novel miRNAs, and analyze differentially expressed miRNAs; 2) profile mRNA expression by RNA sequencing and identify regulatory relationships between mRNA and miRNA by mapping co-expression network modules; 3) analyze miRNA-mRNA pairs, validate altered miRNAs and specific target genes experimentally, and localize these changes at the cellular level; 4) analyze pathway associated with differentially co-expressed modules in MDD; 5) examine miRNA biogenesis by determining pri-/pre-miRNAs, RISC complexes, and components of biogenesis machinery; and 6) examine the role of synaptic miRNAs in MDD pathogenesis by determining miRNA enrichment via small RNA sequencing in synaptosomes, analyzing target genes and co-expression modules of miRNA-mRNA specifically altered in the synaptic fraction, and examining pri-/pre-miRNAs and components of miRNA biogenesis machinery at synaptic level. By using a combination of the state-of-the-art high throughput small RNA and RNA sequencing, analyzing data by novel bioinformatics tools and validation, identifying changes in miRNAs and their targets in specific cell type(s), and examining the role of miRNAs at the synaptic level in brain regions implicated in mood and cognition, our proposed study is uniquely positioned to advance the field of MDD research at the molecular level. These investigations will provide novel avenues for the development of miRNAs as ''molecular tools'' with the potential to generate new molecular-based therapies to treat this devastating disorder.