Mechanisms underlying circular RNA biogenesis in Alzheimer’s disease related genes

阿尔茨海默病相关基因中环状 RNA 生物发生的机制

基本信息

批准号：
10665204
负责人：
Paul Nils Valdmanis
金额：
$ 22.77万
依托单位：
UNIVERSITY OF WASHINGTON
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-04-01 至 2025-03-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10665204
关键词：
Affect Alternative Splicing Alzheimer&apos s Disease Alzheimer&apos s Disease Pathway Alzheimer&apos s disease brain Alzheimer&apos s disease patient Amyloid beta-Protein Biogenesis Brain Cell Line Cells Code Complement Disease Etiology Evaluation Event Exons Generations Genes Genetic Transcription High-Throughput RNA Sequencing Hippocampus Human Hypoxia In Vitro Individual Knowledge Large-Scale Sequencing Late Onset Alzheimer Disease Mediating Messenger RNA Neurodegenerative Disorders Neurons Oxidative Stress Pathogenesis Pathogenicity Pathology Patients Prevalence Process Production Protein Isoforms Proteins RNA RNA Helicase RNA Splicing Regulation Regulatory Element Repetitive Sequence Role Sampling Series Study models Synapses Synaptosomes Testing Therapeutic Tissues Transcript Translations Untranslated RNA Variant abeta accumulation brain tissue circular RNA design differential expression effective therapy frontal lobe glycogen synthase kinase 3 beta glycogen synthase kinase 3 beta inhibitor mRNA Translation mouse model novel novel therapeutic intervention physiologic stressor presenilin-2 preservation prevent repository tau Proteins tau aggregation tau expression tau-1 transcriptome transcriptome sequencing vector

项目摘要

Alzheimer’s disease (AD) is a debilitating and pervasive neurodegenerative disorder with no effective treatments and is predicted to double in prevalence over the next 30 years. One of the first hallmarks of AD is loss of synapses followed by amyloid beta aggregation and tau neurofibrillary tangles. The steps leading to these aggregation events, especially in individuals with late-onset AD, are poorly understood. To better comprehend the transcriptional mechanisms associated with synapse loss, we isolated synapses in the form of synaptosomes and performed high throughput RNA sequencing. We found differentially expressed mRNAs associated with the synapse in AD patients with implications for synaptic transport and local mRNA translation. Notably, when interrogating the noncoding transcriptome, we found a widespread shift of distribution of circular RNAs (circRNAs) from cell bodies to synapses. CircRNAs are stable molecules formed from covalent linkages of conserved back-spliced exon junctions that can compete with linear counterparts. Interestingly among the top differentially expressed circRNAs were two circRNAs from GSK3β, which underwent a switch from one isoform significantly upregulated in AD to another significantly downregulated. GSK3β phosphorylation of tau is essential for its aggregation and GSK3β inhibitors have actively been pursued as translational targets for AD. Further evaluation of GSK3β and other circular RNAs in a large RNAseq repository revealed differentially expressed circRNAs in PSEN2 surrounding exons associated with hypoxia mediated alternative splicing. Therefore, key AD associated proteins have RNA counterparts at the synapse that are differentially expressed that may have critical modulatory roles. Our findings point to a novel mode of regulation at the RNA level. Through a series of in vitro studies and mouse models of tau pathology, we propose to therapeutically modulate the expression of circGSK3B and circPSEN2 isoforms to restore appropriate regulation of tau. We propose to ascertain whether regulatory features surrounding alternative GSK3β exons affect circRNA production and whether RNA helicases influence the GSK3β circRNA isoform switch that we observe. In addition, we will evaluate the relationship between PSEN2 circRNA biogenesis and the role of oxidative stress in affecting aberrant PSEN2 alternative splicing – a phenomenon we observe to be significantly enriched in sporadic AD. Collectively, we will leverage our understanding of the rules governing circRNA biogenesis and regulation to generate molecules capable of preserving appropriate expression of GSK3β and prevent tau aggregation.

阿尔茨海默病（AD）是一种使人衰弱的普遍性神经退行性疾病，目前尚无有效的治疗方法预计未来 30 年患病率将翻一番，这是该病的首要标志之一。 AD 是突触丧失，随后出现β 淀粉样蛋白聚集和tau 神经原纤维缠结。导致这些聚集事件的原因，特别是在患有迟发性 AD 的个体中，人们知之甚少。为了更好地理解与突触丢失相关的转录机制，我们分离了突触我们发现了突触体形式的差异并进行了高通量RNA测序。 AD 患者中表达的与突触相关的 mRNA 对突触运输和值得注意的是，当研究非编码转录组时，我们发现了一种广泛存在的现象。环状RNA（circRNA）从细胞体到突触的分布转移是稳定的。由保守的反向剪接外显子连接的共价连接形成的分子，可以与差异表达最高的 circRNA 中的线性成员是来自 GSK3β，从 AD 中显着上调的一种异构体转变为另一种显着上调的异构体 tau 蛋白的 GSK3β 磷酸化对其聚集至关重要，GSK3β 抑制剂具有抑制作用。正在积极寻求将 GSK3β 和其他环状 RNA 作为 AD 的转化靶标。在大型 RNAseq 存储库中揭示了 PSEN2 外显子周围差异表达的 circRNA 与缺氧介导的选择性剪接有关，因此，关键的 AD 相关蛋白具有 RNA。突触上差异表达的位置可能具有关键的调节作用。通过一系列体外研究和研究发现，RNA 水平上存在一种新的调控模式。在 tau 病理学小鼠模型中，我们建议治疗性调节 circGSK3B 和 circPSEN2 同种型恢复 tau 的适当调节我们建议确定是否有调节作用。围绕替代 GSK3β 外显子的特征影响 circRNA 的产生以及 RNA 解旋酶是否影响我们观察到的 GSK3β circRNA 同工型开关。此外，我们将评估这种关系。 PSEN2 circRNA生物合成与氧化应激在影响异常PSEN2中的作用之间的关系选择性剪接——我们观察到这种现象在散发性 AD 中显着丰富。我们将利用我们对 circRNA 生物发生和调控规则的理解来生成能够保持 GSK3β 适当表达并防止 tau 聚集的分子。