Multimodal Characterization of the Role of Circular RNAs in Alzheimer's Disease

摘要 临床和生物医学研究中的转录学研究主要集中在线性转录本的变化上。 以提供与疾病有关的基因和共表达网络的知识。然而，很少有 已知环状RNA(CircRNAs)在阿尔茨海默病(AD)中的作用。CircRNA是一个新的类别 来自前mRNA外显子和内含子的反向剪接和共价连接的非编码RNA。我们 最近进行了一项转录组范围的CircRNA差异表达分析，从更多的 来自两个独立的大型晚发性散发性AD病例队列的621个大脑样本 没有神经病变的个体。我们确定了特定的CircRNA，包括与AD相关的CircHOMER1 风险和神经病理特征。该项目将使用脑组织来识别与之有关的其他脑组织环状RNA。 在AD中，来自于一个队列，该队列比我们之前研究的队列大四倍。我们还计划调查 阿尔茨海默病患者与对照组血液环状RNA的差异表达以确定其生物标志物的作用 用于创建新的预测模型。我们将建立体外和体内功能的框架 CircRNA在阿尔茨海默病中作用的表征。作为原则的证明，我们将从定义 CircHOMER1在AD相关基因表达和相关细胞表型中的作用。我们已经找到了那个圆环。 在诱导多能干细胞(IPSC)来源的神经元中高表达。我们将使用CRISPR/Cas9来敲门 下调CircHOMER1和利用CircHOMER1过表达(OE)IPSC来源的同源神经元 APP，PSEN1，PSEN2，APP，PSEN1，PSEN2， 和MAPT基因。为了确定CircHmer 1是否在体内加速/增加AD相关的病理，我们将 制备Hmer-1基因敲除转基因小鼠，与5XFAD和MAPT-P301S小鼠杂交。我们会 在5XFAD和MAPT-P301S小鼠的大脑皮层和海马区也使用AAV2/9介导的CircHmer 1 OE。 我们最近发现，7个月大的5XFAD小鼠的CircHmer 1表达显著减少， 与阿尔茨海默病患者死后大脑相似。我们将恢复海马区和大脑皮层的CircHmer 1水平 使用AAV2/9载体对5XFAD和P301S小鼠进行免疫抑制。这份提案将是第一个系统地分析 脑和血液环状RNA在阿尔茨海默病中的作用及体外和体内功能研究 CircRNAs在AD中的作用。

Abstract Transcriptomic studies in clinical and biomedical research have mainly focused on changes in linear transcripts to provide knowledge of the genes and co-expression networks implicated in the disease. However, very little is known about the role of circular RNAs (circRNAs) in Alzheimer's disease (AD). CircRNAs are a novel category of non-coding RNAs derived from the back-splicing and covalent joining of pre-mRNA exons and introns. We recently performed a transcriptome-wide analysis of circRNA differential expression in the brain cortex from more than 621 brain samples from two independent and large cohorts of late-onset sporadic AD cases and neuropathology-free individuals. We identified specific circRNAs, including circHOMER1, associated with AD risk and neuropathological traits. This project will use brain tissue to identify additional brain circRNAs implicated in AD from a cohort that is four-fold larger than the cohort in our previous study. We also plan to investigate differentially expressed blood circRNAs in AD cases compared with controls to determine their biomarker utility for creating new prediction models. We will establish a framework for in vitro and in vivo functional characterization of the role of circRNAs in AD. As proof of principle, we will start by defining the role of circHOMER1 in AD-related gene expression and related cellular phenotypes. We have found that circHOMER1 is highly expressed in induced pluripotent stem cell (iPSC)-derived neurons. We will use CRISPR/Cas9 to knock down circHOMER1 as well as use circHOMER1 overexpression (OE) in iPSC-derived neurons from isogenic controls and AD patient-derived neuronal cultures from pathogenic mutation carriers of APP, PSEN1, PSEN2, and MAPT genes. To determine whether circHomer1 accelerate/increase AD-related pathology in vivo, we will generate circHomer1-knockout transgenic mice and cross them with 5XFAD and MAPT-P301S mice. We will also use AAV2/9-mediated circHomer1 OE in the cortex and hippocampus of 5XFAD and MAPT-P301S mice. We recently found that seven-month-old 5XFAD mice display significant reductions of circHomer1 expression, similar to the postmortem brains of AD patients. We will restore circHomer1 levels in the hippocampus and cortex of 5XFAD and P301S mice using AAV2/9 vectors. This proposal will be the first to systematically analyze the role of brain and blood circRNAs in AD and to perform in vitro and in vivo functional studies to characterize the role of circRNAs in AD.