Expanding the chemical diversity of therapeutic oligonucleotides to treat neurodegenerative disorders

摘要： 治疗性寡核苷酸（例如，小干扰RNA（siRNA）和反义）有希望作为 用于治疗遗传定义的神经退行性疾病的转化药物，包括 亨廷顿病（HD）和肌萎缩侧索硬化（ALS）。siRNA沉默致病基因， 靶向它们的同源mRNA进行降解，从而防止有毒基因产物的表达。 它们固有的序列特异性和延长的活性提供了强大的治疗平台，只要 该疾病是由遗传学确定的，并且可实现向相关靶组织的递送。然而，siRNA 通过注射不能穿过血脑屏障和局部CNS递送， 或毒性。因此，有效且无毒的递送代表了基于RNAi的靶向药物开发中的主要障碍。 治疗神经退行性疾病的药物。 该提案的目标是开发和表征新型化学支架， 寡核苷酸的高效和无毒递送以及中枢神经系统中治疗靶标的有效沉默， 神经系统我们描述了一类完全化学稳定的疏水siRNA（hsiRNAs）， 在推注脑脊液（CSF）输注后整个脑中持久且有效的沉默。 修饰包括寡核苷酸结构、核糖、骨架和添加亲脂性缀合物- 例如，在一个实施方式中，神经活性类固醇，内源性大麻素样脂质，神经节苷脂。广泛构效关系 研究表明，结合物的类型决定了药物的分布、滞留、效力、作用持续时间， HsiRNA-缀合物在中枢神经系统中的毒性。 完成这项提案将（i）定义和表征两种新型化学支架， 中枢神经系统中靶基因的有效、特异性和持久沉默，以及（ii）验证这一点 HD和ALS动物模型的新平台，为两种疾病的新型治疗方法建立了途径。 神经退行性疾病该提案建立了一个平台，允许直接靶向任何基因 在啮齿动物中枢神经系统的任何区域中表达。这项工作的顺利完成将 使中枢神经系统中基因功能的研究成为可能，并为开发新的 基于阿昔单抗的遗传定义的神经退行性疾病的治疗。

ABSTRACT: Therapeutic oligonucleotides (e.g., small interfering RNAs (siRNAs) and antisense) hold promise as transformative drugs for the treatment of genetically defined neurodegenerative disorders, including Huntington's disease (HD) and amyotrophic lateral sclerosis (ALS). siRNAs silence disease-causing genes by targeting their cognate mRNAs for degradation, thereby preventing the expression of toxic gene products. Their inherent sequence specificity and prolonged activity provide a powerful therapeutic platform, as long as the disease is genetically defined and delivery to the relevant target tissue is achievable. However, siRNAs do not cross the blood–brain barrier and local CNS delivery by injection often results in poor retention, distribution or toxicity. Thus, efficient and non-toxic delivery represents a major hurdle in the development of RNAi-based drugs to treat neurodegenerative disorders. The goal of this proposal is to develop and characterize novel chemical scaffolds that promote simple, efficient, and non-toxic delivery of oligonucleotides and potent silencing of therapeutic targets in the central nervous system. We describe a class of fully chemically stabilized hydrophobic siRNAs (hsiRNAs) that elicit durable and potent silencing throughout the brain following bolus cerebrospinal fluid (CSF) infusion. Modifications include oligonucleotides structure, ribose, backbone and the addition of lipophilic conjugates— e.g., neuroactive steroids, endocannabinoid-like lipids, gangliosides. Extensive structure-activity relationship studies reveal that the type of conjugate defines the distribution, retention, efficacy, duration of effect, and toxicity of hsiRNA-conjugates in the central nervous system. Completion of this proposal will (i) define and characterize two novel chemical scaffolds that support potent, specific, and long-lasting silencing of target genes in the central nervous system, and (ii) validate this new platform in animal models of HD and ALS, establishing a path towards novel treatments for two neurodegenerative diseases. This proposal establishes a platform that allows direct targeting of any gene expressed in any region of the central nervous system in a rodent. Successful completion of this work will enable studies of gene function in the central nervous system and pave the way towards development of novel oligonucleotide-based therapies for genetically defined neurodegenerative diseases.