Epitranscriptomic Mapping of Novel N6-Adenosine-based RNA Methylation in MDD Brain

重度抑郁症（MDD）目前仍然是全球残疾的主要原因之一。尽管 随着治疗选择的增加，MDD患者的缓解率非常低。因此，迫切需要确定 在MDD中沉淀的生物基质，以开发有效的治疗方法。众所周知，MDD 涉及对外部刺激的短期和长期适应不良过程，损害个体 适当地与环境互动。到目前为止，还没有一个连贯的假说可以完全解释这一点 现象越来越多的证据表明基因-环境对转录调控的微调 相互作用是MDD病因学的核心。在这方面，最近出现了一种范式转变现象， 引入了独特的概念，即通过表转录组学机制进行转录后基因调控 (most主要是N6-甲基腺苷[m6 A]），其不仅参与转录的调节， 丰富，但具有影响成熟度、稳定性、本地化以及最重要的可用性的深刻能力 的“选择”基因转录蛋白质翻译，尽管不同的转录率在一个高度“动态”， “可逆”的时尚。这种机制促进了对外部刺激的快速反应， 可访问性，并执行本地化的控制，这是刺激适应性基因表达的关键。他们的角色 最近在突触可塑性以及小鼠的压力应对行为中得到了证实。我们自己 初步的数据表明，不仅m6 A mRNA甲基化机制在小鼠中差异表达， 不同的大脑区域，但它们的表达和操纵m6 A甲基化和随后的功能， 特定转录物的表达在MDD脑中异常。这促使我们提出了一个总体的 基于m6 A甲基化mRNA表位转录组修饰可能作为一种动态调节因子的假设 基因的一个子集在大脑区域特定的方式，这是通过影响特定的分子途径， 协调方式，将参与MDD的发病机制。为了验证这一点，在健康人的dlPFC和海马体中， 对照组和匹配良好的MDD受试者，我们提出以下目的：1）检查MDD是否与 具有m6 A甲基化机制的差异调节和不同的m6 A甲基化谱 以脑区特异性方式的epitranscriptomic水平; 2）定义YTH家族阅读者的MDD相关作用 蛋白质编码基因的表型转录组转换中的蛋白质; 3）检查m6 A mRNA甲基化的影响 局部表转录组库的树突可用性及其对MDD发病机制的贡献。通过使用 高度创新的分子方法，通过精确识别转录本的命运， 通过检查m6 A甲基化的作用，通过特定m6 A阅读器蛋白介导的不可翻译池 在突触，并通过使用新的生物信息学工具分析数据，我们的研究是高度创新的;它具有 发现独特的基于表位转录组的基因调控作为MDD发病机制的潜力 并确定新的治疗干预靶点。

Major depressive disorder (MDD) currently remains one of the leading causes of global disability. Despite the rise in treatment options, remission rates in MDD patients are very low. Thus, there is critical need to identify the biological substrates that precipitate in MDD in order to develop effective therapy. It is widely known that MDD involves short- and long-term maladaptive processes to external stimuli, impairing the ability of individuals to appropriately interact with the environment. So far, there is no coherent hypothesis that can fully explain this phenomenon. Increasing evidence suggests that fine-tuning of transcriptional regulation by gene-environment interaction is central to the etiology of MDD. In this regard, a paradigm shifting phenomenon has recently been introduced with the unique concept of post-transcriptional gene regulation through epitranscriptomic mechanism (most prominently being N6-methyladenosine [m6A]) which is not only involved in the regulation of transcript abundance but has the profound ability to impact maturity, stability, localization, and most importantly, availability of “select” gene transcripts to protein translation despite varying transcription rates in a highly “dynamic” and “reversible” fashion. This mechanism facilitates quick response to external stimuli, fine-tunes protein accessibility, and executes localized control, which is critical to stimulus-adaptive gene expression. Their roles have recently been shown in synaptic plasticity as well as in the stress coping behavior of mice. Our own preliminary data demonstrate that not only is m6A mRNA methylation machinery differentially expressed in various brain areas, but their expression and functions in manipulating m6A methylation and subsequent expression of specific transcripts are aberrant in the MDD brain. This has led us to propose an overarching hypothesis that m6A methylation-based epitranscriptomic modification of mRNAs may act as a dynamic regulator of a subset of genes in a brain region specific manner, which, by affecting specific molecular pathways in a coordinated fashion, will participate in MDD pathogenesis. To test this, in dlPFC and hippocampus from healthy controls and well-matched MDD subjects, we propose the following aims: 1) Examine whether MDD is associated with differential regulation of m6A methylation machinery and distinctive m6A methylation profile at the epitranscriptomic level in brain region specific manner; 2) Define MDD associated role of YTH family of reader proteins in epitranscriptomic turnover of protein coding genes; 3) Examine the impact of m6A mRNA methylation on dendritic availability of local epitranscriptomic pool and their contribution to MDD pathogenesis. By using highly innovative molecular approaches, by precisely identifying the fate of the transcripts in translatable and non-translatable pools mediated through specific m6A reader proteins, by examining the role of m6A methylation at the synapse, and by analyzing data using novel bioinformatics tools, our study is highly innovative; it has the potential to discover unique epitranscriptome-based gene regulation as a mechanism in MDD etiopathogenesis and identify novel targets for therapeutic intervention.