MiR-218 regulatory networks in adult mice and its relationship to ALS

项目摘要/摘要 肌萎缩侧索硬化症(ALS)是一种相对罕见的疾病，可导致运动神经元变性。 美国有1：5万人。由于大约50种不同基因的突变与肌萎缩侧索硬化症有关，因此存在令人望而生畏的 治疗将需要开发许多单独的治疗方法的可能性。因此，身份识别 在多种形式的散发性和家族性肌萎缩侧索硬化症中，受影响的共享通路和关键结点可以提供 对整个肌萎缩侧索硬化症社区的影响更大。在这方面，目前许多努力都集中在路径上。 与蛋白质停滞、自噬和细胞应激有关，因为蛋白质聚集是肌萎缩侧索硬化症的共同特征。 这项建议采用了一种互补的方法，通过检查基本马达所起的机械作用。 受ALS影响的神经元特异性microRNA(miR-218)。 持续检测散发性和家族性肌萎缩侧索硬化症的基因表达研究 下调miR-218的表达。最近对ALS患者的一项分析发现，一组患者存在miR-218突变， 提示miR-218水平/活性不足可能是该病的一个危险因素。因为许多与肌萎缩侧索硬化症有关 影响RNA代谢和microRNA加工复合体的基因，推测miR-218的活性是 多种类型的肌萎缩侧索硬化症中基因表达下调，导致基因失调模式，无法维持运动 神经元。相反，据预测，异位miR-218可能恢复运动神经元的适当基因表达 并对抗肌萎缩侧索硬化症。虽然先前的研究已经证实miR-218控制运动神经元的连接 在胚胎中，这项资助的目标是确定成年运动神经元中由miR-218控制的基因网络。 利用遗传学通过精确的时空控制来降低(目标1)和升高(目标2)miR-218。一个有牙线的- 在成年运动神经元中产生了MIR-218等位基因，并在Cre介导的缺失后发现 出现神经肌肉缺陷-表明miR-218是成熟运动神经元中的关键调节分子。在……里面 目的1在成年小鼠运动神经元和下一代RNA测序中有条件地缺失miR-218 来自单核的将被用来(1a)揭示成年运动神经元中的miR-218基因网络，以及(1b)交叉 肌萎缩侧索硬化症小鼠模型中miR-218调节基因与失调基因的相关性。在目标2中，miR-218将 在小鼠中有条件地(异位)表达以(2a)确定mir-218的非细胞自主效应，以及(2b) 模型运动神经元miR-218的基线水平，这将是潜在的肌萎缩侧索硬化症治疗可以耐受的。 这些研究将为未来直接测试miR-218是否可用于衰减的实验铺平道路 肌萎缩侧索硬化。为了实现这一点，提交了一份独立但互补的R03(见补充 应用)，以允许其他使用ALS模型的人使用我们的miR-218试剂探索这一有希望的可能性。这 R21授权是了解miR-218的作用机制及其可能的机制的重要一步 用来减轻肌萎缩侧索硬化症。

PROJECT SUMMARY/ABSTRACT Amyotrophic lateral sclerosis (ALS) is a relatively-rare disease that leads to motor neuron degeneration in 1:50,000 people in the US. Since mutations in ~50 different genes have been linked to ALS, there is the daunting possibility that treatments will require the development of many separate therapies. Consequently, identification of the shared pathways and key nodal points affected in multiple forms of sporadic and familial ALS could provide greater impact for the overall ALS community. In this regard much effort is currently focused on pathways relevant to protein-stasis, autophagy and cell stress, since protein aggregates are a common feature of ALS. This proposal takes a complimentary approach by examining the mechanistic role played by an essential motor neuron-specific microRNA (miR-218) that is affected by ALS. Gene expression studies to identify microRNAs dysregulated in sporadic and familial ALS consistently detect downregulation of miR-218. A recent analysis of ALS patients found a cohort with mutations in miR-218, suggesting insufficient miR-218 levels/activity may be a risk factor for the disease. Because many ALS-linked genes affect RNA metabolism and microRNA processing complexes, it is hypothesized that miR-218 activity is downregulated in many types of ALS leading to a pattern of gene dysregulation that fails to sustain motor neurons. Conversely, it is predicted that ectopic miR-218 may restore proper gene expression in motor neurons and counteract ALS. While previous studies have established that miR-218 controls motor neuron connectivity in embryos, the goal of this grant is to identify the gene networks controlled by miR-218 in adult motor neurons using genetics to decrease (aim 1) and elevate (aim 2) miR-218 with precise spatiotemporal control. A floxed- miR-218 allele was created and following Cre-mediated deletion in adult motor neurons it was found that neuromuscular defects arose - indicating miR-218 is a critical regulatory molecule in mature motor neurons. In Aim 1 miR-218 will be conditionally deleted in adult mouse motor neurons and next generation RNA sequencing from single-nuclei will be used to (1a) uncover the miR-218 gene network in adult motor neurons, and (1b) cross- correlate miR-218-regulated genes with dysregulated genes in mouse models of ALS. In Aim 2, miR-218 will be conditionally (ectopically) expressed in mice to (2a) define non-cell-autonomous effects of mir-218, and (2b) model baseline levels of miR-218 in motor neurons that would be tolerable for potential ALS-therapies. These studies will pave the way for future experiments to directly test whether miR-218 can be used to attenuate ALS. To make this possible an independent but complementary R03 was submitted (see complimentary application) to allow others with ALS-models to explore this promising possibility with our miR-218 reagents. This R21 grant is an important step toward understanding the mechanism-of-action of miR-218 and how it might be used to attenuate ALS.