Development of an UNC13A antisense oligonucleotide treatment for ALS and FTD

开发用于ALS和FTD的UNC 13 A反义寡核苷酸治疗 项目摘要 背景：在97%的ALS病例中，以及大约一半的FTD病例中，TAR DNA结合蛋白43（TDP-43）是 从细胞核丢失到细胞质，在那里形成聚集体。TDP-43的一个主要功能是 在RNA剪接过程中，细胞核抑制隐蔽外显子（CE）的包含。最近的研究表明，CE 当TDP-43从神经元的核中耗尽时，包括在UNC 13 A mRNA中， UNC 13 A蛋白。UNC 13 A单核苷酸多态性（SNPs）是与癌症相关的最强命中之一。 与ALS和FTD在人类GWAS研究中的关系。CE位于与主要风险相同的内含子区域 苏格兰民族党风险SNP加剧了UNC 13 A CE入选-具有两种风险等位基因的ALS / FTD患者 CE入选率高于携带一个风险等位基因的患者，携带一个风险等位基因的患者的CE入选率高于携带 非风险等位基因。类似地，风险SNP携带者的存活率具有剂量依赖性降低。这种附加风险 这强烈表明靶向UNC 13 A以抑制CE包含可能具有实质性的治疗效果， 效益由于几乎所有的ALS患者都有TDP-43病理学，因此这种治疗将使他们受益，而不是使他们受益。 仅限于SNP携带者。UNC 13 A在突触传递中起关键作用，并且对于突触传递是必需的。 囊泡在大多数兴奋性突触和神经肌肉接头处释放。在所有已知的基因中 由于TDP-43从细胞核丢失而失调，只有UNC 13 A具有如此强的遗传验证。改变 TDP-43缺失背景下的STMN 2表达是ALS / FTD的标志，但ALS与FTD之间无关联。 风险和STMN 2变体已经确定。因此，应优先考虑UNC 13 A靶向治疗， 快速推进到临床概念验证研究。 AcuraStem的使命是确定拯救多种形式的ALS / FTD的目标。我这样 建立了遗传性和散发性疾病的患者特异性ALS / FTD疾病模型。我们 在这些模型中显示，来自具有风险SNP的ALS患者的皮质神经元具有更多的UNC 13 A， CE包含比来自ALS患者的非风险等位基因的神经元。当我们耗尽TDP-43 使用短干扰RNA（siRNA）的患者来源的神经元，它诱导了CE的稳健包含，并减少了 正常的UNC 13 A mRNA和蛋白质水平。反义寡核苷酸（ASO）是 CNS中遗传靶点（如UNC 13 A）的一种有吸引力的方法，取得了几项成功，包括nusinersen 治疗脊髓性肌萎缩症（SMA）和即将被批准用于治疗SOD 1-ALS的tofersen。我们用我们的专利 阿索设计平台，合成了>125个ASO，并鉴定了几个新的阿索序列， 阻断CE包涵体并恢复UNC 13 A mRNA和蛋白水平。AcuraStem定位独特， 有效的UNC 13 A阿索候选物，可用于ALS和FTD的临床。 目标和影响：这个直接进入第二阶段的项目旨在优化这些候选人并确定真正的候选人 在研究性新药（IND）的毒性研究中取得进展的开发候选人。这 该项目涉及与杰克逊实验室合作，以表征一种新的人类UNC 13 A TDP-43 ALS / FTD小鼠模型，该模型对于该领域至关重要。这个项目在商业上成功的可能性很大 因为目前还缺乏能够治疗散发性ALS的疾病缓解治疗方法 和FTD人群，这是一个巨大的未满足需求和商业机会。

Development of an UNC13A antisense oligonucleotide treatment for ALS and FTD Project Summary Background: In 97% of ALS cases, and roughly half of FTD cases, TAR DNA-binding protein 43 (TDP-43) is lost from the nucleus to the cytoplasm, where it forms into aggregates. A major function of TDP-43 in the nucleus is to repress cryptic exon (CE) inclusion during RNA splicing. Recent studies have shown that a CE is included in UNC13A mRNA when TDP-43 is depleted from the nucleus of neurons resulting in a loss of UNC13A protein. UNC13A single nucleotide polymorphisms (SNPs) are among the strongest hits associated with ALS and FTD in human GWAS studies. The CE is located in the same intronic region as the primary risk SNP. The risk SNP exacerbates the UNC13A CE inclusion - ALS / FTD patients with both risk alleles have more CE inclusion than patients with one risk allele, who have more CE inclusion than patients with the non-risk alleles. Similarly, risk SNP carriers have a dose-dependent reduction in survival. This additive risk strongly suggests that targeting UNC13A to suppress the CE inclusion could have a substantial therapeutic benefit. Since nearly all ALS patients have TDP-43 pathology, such a treatment would benefit them and not be limited to SNP carriers. UNC13A plays a critical role in synaptic transmission and is essential for synaptic vesicle release at most excitatory synapses and neuromuscular junctions. Among all the genes known to be dysregulated by the loss of TDP-43 from the nucleus, only UNC13A has such strong genetic validation. Altered STMN2 expression in the context of TDP-43 depletion is a hallmark of ALS / FTD, yet no link between ALS risk and STMN2 variants has been established. Thus, UNC13A targeting treatments should be prioritized for rapid advancement into clinical proof of concept studies. AcuraStem’s mission is to identify targets that rescue multiple forms of ALS / FTD. Thus we have established patient-specific ALS / FTD disease models of both genetically defined and sporadic diseases. We show in these models that cortical neurons derived from an ALS patient with the risk SNP have more UNC13A CE inclusion than neurons derived from ALS patients with non-risk alleles. When we depleted TDP-43 in patient-derived neurons using short interfering RNAs (siRNA) it induced a robust inclusion of CEs and reduced normal UNC13A mRNA and protein levels across many patient lines. Antisense oligonucleotides (ASOs) are an attractive approach for genetic targets in the CNS like UNC13A with several successes, including nusinersen for spinal muscular atrophy (SMA) and tofersen, soon to be approved for SOD1-ALS. We used our proprietary ASO design platform to synthesize >125 ASOs and identified several novel ASO sequences that potently blocked CE inclusion and restored UNC13A mRNA and protein levels. AcuraStem is uniquely positioned with potent UNC13A ASO candidates that can be advanced towards the clinic for ALS and FTD. Objectives & Impact: This Direct to Phase 2 project aims to optimize these candidates and identify a bona fide development candidate for advancement in investigational new drug (IND)-enabling toxicity studies. This project involves collaborating with the Jackson Laboratory to characterize a new human UNC13A TDP-43 ALS / FTD mouse model that will be essential for the field. This project has a high probability of commercial success because there is a dearth of disease-modifying treatments in development that could work for the sporadic ALS and FTD population, a large unmet need and commercial opportunity.