The role of acetylation in regulating pathophysiology of tau

描述(由申请人提供)：我们试图确定组蛋白脱乙酰酶6(HDAC6)和应激颗粒(SGS)相互作用的分子机制，通过这些分子机制，组蛋白脱乙酰酶6(HDAC6)和应激颗粒(SGS)相互作用，推动额颞叶痴呆等疾病的病理生理学。在这样做的时候，我们将检验这样的假设，即HDAC6活性的丧失会增加位点特异性的tau乙酰化，防止tau的病理性募集到应激颗粒，并减缓疾病的进展。我们最近报道了HDAC6介导的tau去乙酰化增强了tau的聚集和聚集，我们现在已经确定了受HDAC6调控的tau上的乙酰化位点。我们最近还报道，在人类和小鼠模型中，tau病理与SG病理发展一致。了解HDAC6在调节tau中的作用具有额外的意义，因为HDAC6调节SGS，SGS是响应翻译抑制而形成的蛋白质/RNA复合体。因此，HDAC6作为一个纽带发挥作用，将tau的乙酰化、SG的形成和疾病的进展联系起来。这项工作将阐明HDAC6调节tau向SGS募集的机制，特别是tau乙酰化，并评估反义寡核苷酸(ASOS)降低HDAC6表达是否足以缓解tau和SG的病理。我们已经确定了针对HDAC6的ASO有效地减少了小鼠初级神经元的表达，并通过与Isis制药公司的积极合作，正在努力识别将在体内进展的ASO 测试。由于HDAC6的抑制或敲除对细胞或小鼠没有明显的毒性，HDAC6作为治疗靶点具有很强的翻译吸引力。我们的建议是为了更好地理解HDAC6和tau之间复杂的动态关系，以及阐明HDAC6和tau乙酰化在SG动力学中的作用。我们将在HDAC6反应部位产生乙酰tau抗体，以研究在我们的细胞培养和rTg4510小鼠模型中，这些关键部位上的乙酰化如何影响tau生物学和SG动力学，以及来自tau病病例的死后脑组织(目标1)。我们还将通过使用ASOS来确定HDAC6的调制是否减少了在体内的直立性反常并保留了认知(目标2)。利用小鼠的原代神经元、来自人类脊椎病患者的成纤维细胞衍生的神经元(我们发现这些神经元在应激反应中显示出强大的SG形成)，以及用HDAC6 ASOS处理的rTg4510小鼠，我们将进一步确定HDAC6、tau和乙酰化在调节应激颗粒动力学中的作用(目标3)。这些研究的完成将从根本上扩大我们对肌萎缩侧索硬化症的病理生理学的了解，并为HDAC6 ASO作为一种新的治疗策略的临床前疗效提供关键的见解。

DESCRIPTION (provided by applicant): We seek to define the molecular mechanisms by which histone deacetylase 6 (HDAC6) and stress granules (SGs) interactively drive the pathophysiology of tauopathies, such as Frontotemporal Dementia. In so doing, we will test the hypothesis that loss of HDAC6 activity augments site-specific tau acetylation, preventing the pathological recruitment of tau to stress granules, and slowing disease progression. We recently reported that HDAC6-mediated deacetylation of tau enhances accumulation and aggregation, and we have now identified the acetylation sites on tau that are regulated by HDAC6. We also recently reported that tau pathology develops in concert with SG pathology in human and mouse models. Understanding the role of HDAC6 in regulating tau acquires added significance because HDAC6 regulates SGs, which are protein/RNA complexes that form in response to translational inhibition. Thus, HDAC6 functions as a nexus, linking acetylation of tau, SG formation and disease progression. The work in this proposal will elucidate the mechanisms by which HDAC6 regulates tau recruitment to SGs, with a particular focus on tau acetylation, and also assess whether decreasing HDAC6 expression with antisense oligonucleotides (ASOs) is sufficient to alleviate both tau and SG pathology. We have already identified ASOs targeting HDAC6 that effectively decrease expression in mouse primary neurons, and through an active collaboration with Isis Pharmaceuticals, are working to identify ASOs that will progress to in vivo testing. Given HDAC6 inhibition or knockout produces no obvious toxicity in cells or in mice, HDAC6 as a therapeutic target possesses strong translational appeal. Our proposal is structured to provide a greater understanding of the intricate and dynamic relationship between HDAC6 and tau, as well as elucidate the role of HDAC6 and tau acetylation in SG dynamics. We will generate acetyl tau antibodies on HDAC6-responsive sites to investigate how acetylation on these key sites affects tau biology and SG dynamics in our cell culture and rTg4510 mouse models as well as postmortem brain tissue from tauopathy cases (Aim 1). We will also determine whether modulation of HDAC6, through the use of ASOs, diminishes tauopathy and preserves cognition in vivo (Aim 2). Using mouse primary neurons, fibroblast-derived neurons from human tauopathy patients, which we show exhibit robust SG formation in response to stress, and rTg4510 mice treated with HDAC6 ASOs, we will further determine the roles of HDAC6, tau and acetylation in regulating stress granule dynamics (Aim 3). Completion of these studies in tandem will fundamentally expand our knowledge of the pathophysiology of tauopathies, and provide key insights into the pre-clinical efficacy of HDAC6 ASOs as a novel therapeutic strategy.