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

ALS、FTD 和阿尔茨海默病都是复杂的疾病，每种疾病均由多种不同的遗传病因引起。 尽管针对特定因果突变（例如 SOD1 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，这些方法无法解决绝大多数病例 具有未知的遗传病因。此外，考虑到大量不同的基因可能有助于 ALS 和 FTD 以及每种遗传形式都相对罕见，这一策略可能难以实施 对于所有情况。因此，迫切需要新的治疗策略来挽救多种形式的疾病 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 为了拯救多种形式的 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 C9ORF72 和散发性 ALS 患者的 iPSC 运动神经元退化。抑制剂 PIKFYVE 激酶是跨患者系列最有效且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退行性变 溶酶体融合，诱导分泌性自噬清除错误折叠的蛋白质，包括 C9ORF72 二肽 通过外泌体分泌重复蛋白和 TDP-43。错误折叠蛋白质的积累可诱导 神经元死亡是神经退行性疾病的一个共同特征。尽管研究试图 刺激已知的蛋白质稳态途径，包括蛋白酶体和自噬，这些途径会下降 老化过程中，可能难以有效抢救。有趣的是，最近的研究表明神经元使用 外泌体分泌作为第三种蛋白质稳态途径。但这条途径能否成功仍不得而知 用于治疗 ALS 和相关的神经退行性疾病。拟议研究的中心假设 分泌性自噬是预防 ALS、FTD 和 FTD 神经退行性变的最有效方法之一 阿尔茨海默病与该领域的主流思维不同。评估这个假设至关重要，因为 激活蛋白酶体和自噬在神经退行性变模型中产生了不同的结果。拟议的 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中的功效 神经元，3) 验证体内反义寡核苷酸抑制 PIKFYVE 的功效。 该应用旨在通过验证分泌性自噬的诱导作为一种方法来改变当前的研究 针对多种形式的 ALS、FTD 和阿尔茨海默病的高效治疗策略。的 拟议的研究将确定 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目标。更广泛地说，这种治疗策略可能 对由异常蛋白质积累引起的其他疾病有效。

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.