Role of selective autophagy in aging and neurodegeneration: a small molecule approach

项目摘要/摘要 衰老的一个假说是，细胞损伤的积累会导致组织功能障碍和器官损伤。 恶化。维持细胞动态平衡和保持细胞功能的关键机制是自噬， 一种水解性细胞循环过程，在这个过程中，胞浆物质，称为货物，包括脂滴 (LDS)和受损的蛋白质在溶酶体中降解。反过来，自噬过程中的异常会导致 不同毒性胞浆内容物的积累，这是许多与年龄相关的疾病的分子特征， 包括神经退行性变。虽然自噬、衰老和疾病之间存在显著的功能联系， 导致自噬与年龄相关的减少的分子机制尚不清楚。 值得注意的是，自噬也可以选择性地招募一种类型的分子进行降解。最近的研究支持 认为选择性自噬在对抗慢性病中起关键作用的假说。几个人脑 尸检研究发现阿尔茨海默病患者大脑中积聚的脂类物质 (AD)，可能阻碍神经元功能，从而导致神经退行性变。因此，发现 不同的干预措施可以用来选择性地影响脂噬作用(LD更替)，这可能是解决问题的理想方法 脂质毒性相关的阿尔茨海默病然而，目前还没有这样的药理或遗传工具。此外， 促进LD募集以促进吞脂作用的选择性细胞因子仍不清楚。在这项提议中，我的目标是 为了解决这些在理解脂噬调节机制及其功能方面的更大需求 与衰老和神经退行性疾病有关。 我们实验室最近进行了细胞LD清除高通量筛查，以识别小分子和 诱导选择性清除脂类自噬以减缓年龄相关疾病的途径。其中，我们 鉴定了化合物A20，它以自噬依赖的方式清除线虫体内的脂类至 促进健康长寿。新出现的证据表明，A20可能通过吞脂作用来清除脂质。我 假设发现A20利用的吞脂机制将有助于我们识别新的吞脂性 监管者。此外，由于脂质堆积现在与阿尔茨海默病有关，我将雇用一名新的人类AD患者- 衍生器官模型(星形胶质细胞3D神经元培养)以确定A20是否使脂质正常化。 关联致病特征并使致病分子表型正常化。最后，我将描述 使用这些人源性有机体模型研究AD期间吞脂性和脂质动态平衡的功能变化。 我的研究意义重大，因为它们将帮助我们对吞脂性激活产生新的机械论见解 在衰老过程中与AD有关。这些知识对于加深我们对呈现吞脂性疾病的理解至关重要。 放松管制的组成部分。此外，这些研究的完成可能会揭示出可能 被用来对抗神经退行性疾病。

PROJECT SUMMARY/ABSTRACT A hypothesis of aging is that the accumulation of cellular damage can lead to tissue malfunction and organismal deterioration. A key mechanism for maintaining cellular homeostasis and preserving cell function is autophagy, a hydrolytic cellular recycling process whereby cytosolic materials, referred to as cargo, including lipid droplets (LDs) and damaged proteins, are degraded in the lysosome. In turn, aberrations in autophagy can result in the accumulation of different toxic cytosolic contents, which is a molecular signature of many age-related disorders, including neurodegeneration. While there is a prominent functional link between autophagy, aging and diseases, the molecular mechanisms that cause the age-dependent decreases in autophagy remain unclear. Notably, autophagy can also selectively recruit one type of molecule for degradation. Recent studies support the hypothesis that selective autophagy plays a crucial role in combating chronic diseases. Several human brain post-mortem studies have uncovered lipid species that accumulate in brains affected by Alzheimer’s disease (AD), possibly impeding neuronal function and thereby contributing to neurodegeneration. Therefore, discovering different interventions that can be used to affect lipophagy (LD turnover) selectively may be ideal for tackling lipidotoxicity-linked AD. However, such pharmacological or genetic tools are currently unavailable. Furthermore, selective cellular factors that can facilitate LD recruitment for lipophagy remain unknown. In this proposal, I aim to address these greater needs in understanding the regulatory mechanisms of lipophagy and its function relevant to aging and neurodegenerative disorders. Our lab recently performed a cellular LD clearance high-throughput screen to identify small molecules and pathways that induce selective lipid clearing autophagy for slowing age-related diseases. Among these, we identified compound A20 that clears lipids in an autophagy-dependent manner in the nematode C. elegans to promote healthspan and lifespan. Emerging evidence suggests that A20 may act via lipophagy to clear lipids. I hypothesize that uncovering the lipophagy mechanism utilized by A20 will help us identify novel lipophagy regulators. Furthermore, since lipid accumulation is now linked to AD, I will employ a novel human AD patient- derived organoid model (3D neuronal culture with astrocytes) to determine whether A20 normalizes the lipid- linked pathogenic signature and normalizes pathogenic molecular phenotypes. Finally, I will characterize the functional changes in lipophagy and lipid homeostasis during AD using these human-derived organoid models. My studies are significant, as they will help us generate new mechanistic insights towards lipophagy activation during aging linked to AD. Such knowledge is vital to further our understanding of diseases exhibiting a lipophagy deregulation component. Furthermore, completion of these studies may potentially reveal strategies that could be used to combat neurodegenerative diseases.