Validating Secretory Autophagy as a Therapeutic Strategy for Diverse Forms of ALS and FTD

ALS、FTD和阿尔茨海默氏症是复杂的疾病，每种疾病都是由许多不同的遗传病因引起的。 尽管靶向特定因果突变（例如SOD 1 ASO）的治疗策略可能被证明是有效的， 针对个别形式的ALS和FTD，这些方法不能解决绝大多数病例， 遗传病因不明。此外，考虑到大量不同的基因可能有助于 ALS和FTD以及每种遗传形式相对罕见的事实，这种策略可能难以实施 对于所有情况。因此，迫切需要新的治疗策略，以挽救多种形式的癌症。 ALS和FTD，尤其是那些遗传病因不明的患者。确定新的治疗靶点， 拯救多种形式的ALS，我们进行了公正的化学筛选，以寻找可以拯救的目标， 来自多个C9 ORF 72和散发性ALS患者的iPSC运动神经元的变性。的抑制剂 PIKFYVE激酶是跨患者线的最有效和最广泛有效的化合物之一。 令人惊讶的是，数据显示PIKFYVE抑制通过阻断自噬体来挽救神经变性。 溶酶体融合，其诱导分泌性自噬以清除包括C9 ORF 72二肽在内的错误折叠蛋白 重复蛋白和TDP-43通过外泌体分泌。错误折叠蛋白的积累可以诱导 神经元死亡并且是神经变性疾病的共同特征。尽管研究试图 刺激已知的蛋白质稳定途径，包括蛋白体和自噬，这些途径下降 在老化期间，可能难以有效地抢救。有趣的是，最近的研究表明， 外泌体分泌作为第三种蛋白质稳态途径。然而，目前尚不清楚这一途径是否可以 用于治疗ALS和相关的神经退行性疾病。这项研究的核心假设是 分泌性自噬是防止ALS、FTD和 阿尔茨海默病不同于该领域的主流思想。评估这一假设至关重要，因为 激活蛋白酶体和自噬在神经变性模型中具有混合的结果。拟议 研究将1）证实分泌性自噬是PIKFYVE抑制的治疗机制，2） 确定分泌性自噬在ALS、FTD和阿尔茨海默病患者来源的 神经元，和3）在体内验证用反义寡核苷酸抑制PIKFYVE的功效。 该申请试图通过验证分泌性自噬的诱导作为一种免疫调节剂来改变当前的研究。 针对各种形式的ALS、FTD和阿尔茨海默病的高效治疗策略。的 拟议的研究将建立PIKFYVE抑制和分泌性自噬作为关键治疗 ALS和相关神经退行性疾病的靶点。更广泛地说，这种治疗策略可能 对其他由异常蛋白质积累引起的疾病有效。

ALS, FTD, and Alzheimer’s are complex diseases that each result from many diverse genetic etiologies. Although therapeutic strategies that target specific causal mutations (e.g. SOD1 ASOs) may prove effective against individual forms of ALS and FTD, these approaches cannot address the vast majority of cases that have unknown genetic etiology. Moreover, given the large number of different genes that likely contribute to ALS and FTD and the fact that each genetic form is relatively rare, this strategy may be difficult to implement for all cases. Thus, there is a pressing need for new therapeutic strategies that rescue multiple forms of ALS and FTD, particularly those with unknown genetic etiologies. To identify new therapeutic targets that rescue multiple forms of ALS, we performed unbiased chemical screens to search for targets that can rescue the degeneration of iPSC motor neurons from multiple C9ORF72 and sporadic ALS patients. Inhibitors of PIKFYVE kinase were among the most potent and broadly-efficacious compounds across patient lines. Surprisingly, the data show that PIKFYVE inhibition rescues neurodegeneration by blocking autophagosome- lysosome fusion, which induces secretory autophagy to clear misfolded proteins including C9ORF72 dipeptide repeat proteins and TDP-43 through exosomal secretion. The accumulation of misfolded proteins can induce neuron death and is a common feature of neurodegenerative diseases. Although studies have sought to stimulate known proteostasis pathways including the proteosome and autophagy, these pathways decline during aging and may be difficult to rescue effectively. Intriguingly, recent studies have shown that neurons use exosomal secretion as a third proteostasis pathway. However, it remains unknown if this pathway can be harnessed to treat ALS and related neurodegenerative diseases. The central hypothesis of the proposed study that secretory autophagy is one of the most potent ways to prevent neurodegeneration in ALS, FTD, and Alzheimer’s disease differs from mainstream thinking in the field. Evaluating this hypothesis is crucial because activating the proteasome and autophagy has had mixed results in neurodegeneration models. The proposed study will 1) confirm that secretory autophagy is the therapeutic mechanism of PIKFYVE inhibition, 2) determine the efficacy of secretory autophagy in ALS, FTD, and Alzheimer’s disease patient-derived neurons, and 3) validate the efficacy of PIKFYVE suppression with antisense oligonucleotides in vivo. This application seeks to shift current research by validating the induction of secretory autophagy as a highly effective therapeutic strategy for diverse forms of ALS, FTD, and Alzheimer’s disease. The proposed study will establish PIKFYVE suppression and secretory autophagy as critical therapeutic targets for ALS and related neurodegenerative diseases. More broadly, this therapeutic strategy may be effective for other diseases driven by aberrant protein accumulation.