Identifying kinase signaling pathways linked to tau-mediated neurodegeneration

项目总结 在阿尔茨海默病(AD)的发病机制中，tau的病理与神经退行性变和认知有关 拒绝。在过去的十年里，我们一直在研究tau在AD中是如何发挥其毒性的。在众多的Tau帖子中- 翻译修饰(PTM)，现在已知同时发生和靶向tau，tau的赖氨酸的乙酰化， 从最近的低温EM和质谱学研究中发现的，是一个特别相关的和 吸引人的目标。再加上乙酰化加速了tau的聚集，防止了正常 微管结合，并导致突出的AD样缺陷，包括突触功能障碍和认知功能障碍 ，这些性质似乎使这种特殊的PTM有别于许多其他tau PTM 是已知的调节tau的。虽然乙酰化tau在几乎所有散发性AD脑中都很常见，但仍然很少 可靠的模型可以解开汇聚在这一想法上的信号事件和酶。在我们看来，这一差距 如果我们希望揭示驱动tau发病的机制，就需要克服这些问题。我们发现了一种新的 帕金森病相关蛋白LRRK2上游调控的信号通路 HDAC，因此间接控制tau乙酰化。我们假设LRRK2和其他相关的“HDAC” 激酶“作为HDAC功能的主要调节者，其最终目标是防止 乙酰化的tau，从而防止tau的毒性。在AIM-1中，我们开发了一个新的模型，该模型基于一个 工程化胞浆CBP乙酰转移酶精确靶向胞浆tau，然后评估其程度 Tau病理、突触功能障碍、tau播种和tau繁殖。将HDAC 3/6的范围缩小为 在所有人类HDAC中唯一与tau相关的HDAC，我们将把它们传递给神经元并确定 HDAC之间的协同作用是否会聚到tau上以抑制其毒性。在AIM-2中，我们重点介绍 协调HDAC活动的上游激酶。我们探索LRRK2作为一个非常有吸引力的热门在一个迷你 调制HDAC3/6功能的屏幕。我们将在小鼠神经元、小鼠和 评估人类IPSC神经元对HDAC和tau的下游影响。我们的提议将会揭示真相， 不仅针对与AD相关的HDAC，而且还开辟了新的治疗途径(例如，针对上游 激酶)来抑制大脑中有毒的tau物种。因此，这一建议既具有创新性，又具有重要意义。 由于包括LRRK2和PKC在内的上游HDAC调节激酶有望成为意想不到的调节因子 HDAC活动的数量。这将扩大我们在包括AD和AD在内的tauopathy中的靶向通路的曲目 甚至连警察也是。

PROJECT SUMMARY At the heart of Alzheimer’s (AD) pathogenesis, tau pathology is linked to neurodegeneration and cognitive decline. We have spent the last decade addressing how tau exerts its toxicity in AD. Among the many tau post- translational modifications (PTMs) that are now known to co-occur and target tau, acetylation of tau’s lysines, which have emerged from recent cryo-EM and mass spectrometry studies, is a particularly relevant and attractive target. Coupled with the fact that acetylation accelerates tau aggregation, prevents normal microtubule binding, and induces prominent AD-like deficits including synaptic dysfunction and cognitive decline, these properties would appear to set this particular PTM apart from many of the other tau PTMs that are known to regulate tau. While acetylated tau is common to virtually all sporadic AD brains, there remain few reliable models to unravel the signaling events and enzymes that converge on this idea. In our view, this gap needs to be overcome if we hope to unravel mechanisms that drive tau pathogenesis. We identified a new signaling pathway in which the Parkinson’s disease (PD)-relevant kinase LRRK2 acts upstream to regulate HDACs and therefore indirectly controls tau acetylation. We hypothesize that LRRK2 and other related “HDAC kinases” act as master regulators of HDAC function, with their end goal of preventing the accumulation of acetylated tau and thereby protecting against tau toxicity. In Aim-1, we develop a new model based on an engineered cytoplasmic CBP acetyltransferase to precisely target cytoplasmic tau and then assess the extent of tau pathology, synaptic dysfunction, tau seeding, and tau propagation. Having narrowed in on HDACs 3/6 as the only tau-associated HDACs among all human HDACs, we will deliver them to neurons and determine whether synergism among HDACs converges onto tau to suppress its toxicity. In Aim-2, we focus on the upstream kinases that coordinate HDAC activity. We explore LRRK2 as a very attractive hit identified in a mini screen that modulates HDAC3/6 function. We will manipulate LRRK2 function in mouse neurons, mice, and human iPSC neurons to evaluate downstream consequences on HDACs and tau. Our proposal will shed light, not only on AD-relevant HDACs, but also open up new therapeutic avenues (e.g., the targeting of upstream kinases) to suppress toxic tau species in the brain. This proposal is therefore both innovative and significant since upstream HDAC regulatory kinases including LRRK2 and PKC hold promise as unanticipated regulators of HDAC activity. This will expand our repertoire of targetable pathways in tauopathies that include AD and even PD as well.