Neurovascular functions of a small RNA Snord118-mediated ribosome biogenesis

项目总结/摘要 神经血管单位（NVU）功能障碍导致与小血管相关的弥漫性白色物质障碍。 血管疾病（SVD），其影响约50%的所有痴呆症，包括阿尔茨海默病和 阿尔茨海默病相关性痴呆（AD/ADRD）。核糖体病是一组人类疾病引起的 通过核糖体蛋白质或核糖体生物发生因子的突变。一个通用核糖体的失调 生物发生过程导致的组织特异性表型仍然知之甚少。这项提案的目的是 开发两种新的SVD遗传小鼠模型，并使用它们来确定NVU细胞类型是如何 选择性地易受普遍存在的核糖体生物合成过程的破坏。我们将专注于 非编码RNA Snord 118，其编码核糖体生物发生因子。人类Snord 118点突变 导致SVD，称为伴有钙化和囊肿的白质脑病（LCC）， 核糖体病的神经系统疾病。我们收集了以下初步数据：1）生成两个 独立的疾病点突变敲入（KI）小鼠模型，其显示患者样运动和认知 行为异常; 2）确定周细胞损失，微血管和白色物质损伤，在这些 Snord 118 KI小鼠脑，其反映了血管单位受损而不引起致死性出血; 3） 开发了一种新的基于交联和测序的技术，称为巴黎，以高通量绘制RNA图谱 结构和RNA-RNA相互作用在单分子和全基因组水平与碱基对分辨率; 4） 使用巴黎和确定Snord 118在小鼠大脑中的早期发育阶段的目标。初步数据 使我们假设Snord 118突变介导的核糖体生物合成的破坏选择性地影响 NVU细胞通过靶向rRNA和非rRNA导致LCC样表型。为了验证这个假设，两个 提出了具体目标。目的1建立LCC小鼠模型，并鉴定NVU细胞在LCC中的表达， 选择性受Snord 118突变影响。目的2将使用巴黎与KI小鼠偶联以鉴定Snord 118 体内靶点并确定Snord 118 RNA结构-功能关系。使用我们的新KI鼠标和最新的 巴黎，这项研究将产生第一个易于处理的小鼠模型，目前还不存在Snord 118 LCC， 确定Snord 118作用和LCC疾病的机制，发现以前未知的 特异性NVU细胞破坏普遍存在的核糖体生物合成过程，因此有助于调和 核糖体病的神经学表型特异性与核糖体生物合成的整体要求 在所有的细胞。

PROJECT SUMMARY / ABSTRACT Dysfunction of neurovascular unit (NVU) contributes to diffuse white matter disorder associated with small- vessel disease (SVD), which affects approximately 50% of all dementia, including Alzheimer's disease and Alzheimer's disease-related dementias (AD/ADRD). Ribosomopathies are a group of human disorders caused by mutations in ribosomal proteins or ribosome biogenesis factors. How dysregulation of a universal ribosome biogenesis process leads to tissue-specific phenotypes remains poorly understood. The goal of this proposal is to develop two new genetic mouse models for SVD and use them to determine how NVU cell type(s) are selectively vulnerable to the disruption of a ubiquitous ribosome biogenesis process. We will focus on noncoding RNA Snord118, which encodes a ribosome biogenesis factor. Snord118 point mutations in humans lead to SVD named leukoencephalopathy with calcifications and cysts (LCC), which represents the first purely neurological disorder in ribosomopathies. We have assembled the following preliminary data: 1) generated two independent disease point mutation knock-in (KI) mouse models, which display patient-like motor and cognitive behavioral abnormalities; 2) identified pericyte loss, and microvascular and white matter injury in these Snord118 KI mouse brains, which reflects the vascular unit impairment without causing lethal hemorrhage; 3) developed a new crosslinking and sequencing based technology named PARIS to high throughput map RNA structures and RNA-RNA interactions at single molecule and genome-wide levels with base-pair resolution; 4) used PARIS and identified Snord118 targets in mouse brains at early developmental stage. Preliminary data led us to hypothesize that Snord118 mutation-mediated disruption of ribosome biogenesis selectively affects NVU cells via targeting rRNAs and non-rRNAs leading to LCC-like phenotypes. To test this hypothesis, two specific aims are proposed. Aim 1 will establish mouse models of LCC and identify how NVU cell(s) are selectively affected by Snord118 mutations. Aim 2 will use PARIS coupled with KI mice to identify Snord118 targets in vivo and determine Snord118 RNA structure-function relationships. Using our new KI mice and latest PARIS, this study will generate the first tractable mouse models that do not currently exist for Snord118 LCC, identify mechanisms of Snord118 action and LCC disease, uncover a previously unknown vulnerability of specific NVU cells to the disruption of a ubiquitous ribosome biogenesis process, therefore help to reconcile the neurological phenotype specificity of ribosomopathies with the global requirement of ribosome biogenesis in all cells.