能量感受分子AMPK调控AD样tau病理和行为改变的分子机制

Alzheimer’s disease (AD) is a common neurodegeneration disease. T2DM is an independent risk factor of AD， our previous data has also shown that there were AD-like tau hyperphosphorylation and AMPK activity decrease in insulin-resistance rodent model , but its underlying mechanisms of T2DM inducing AD-like tauopathies still remain elusive. The preliminary experimental results demonstrated that AMPK activity is negative relation with tau acetylation level. It has been reported that the abnormal acetylation of tau is early tauopathies. So we proposed that AMPK activity decrease induced acetylation of tau and tau-related protein kinases and phosphatases and then resulted in tauopathies and brain functional impairment in insulin-resistance development. In current study, the models of brain insulin resistance will be established with drug or high fat diet in HA-Ribo-Tag LoxP mice. The AVV-Cre-GFP virus will be injected into brain of model mice with stereotaxic technology. The levels (including mRAN and protein) and distribution of AMPK/Sirt1, tau and its associated phosphorylated or acetylated enzymes (including phosphorylation and acetylation of these molecular) will be measured and the brain function also will be tested in the project. The mechanisms of AMPK regulating tauopathies and brain function impairment also will be explored in cell of insulin resistance, these results will disclose the roles of metabolism-related target in AD prevention and therapy.

阿尔茨海默病（Alzheimer Disease，AD）是一种最常见的神经退行性疾病。Ⅱ型糖尿病是AD发病的独立危险因素，我们前期的研究也证实，脑胰岛素抵抗鼠模型出现AD样tau磷酸化和AMPK活性降低，但机制不清。预实验发现，AMPK与tau乙酰化密切相关；研究发现tau蛋白异常乙酰化是AD早期病变。由此可见，胰岛素抵抗增加AD危险性的机制可能是由于AMPK活性降低，导致tau及其修饰酶乙酰化，进而引起tau病变和脑功能损伤。研究拟采用HA-Ribo-Tag LoxP小鼠，建立脑胰岛素抵抗动物模型，脑注射AVV-Cre-GFP病毒，分析不同脑区特定神经元AMPK/Sirt1、tau病理和脑功能变化的时间和空间变化规律；在细胞胰岛素抵抗模型，探讨AMPK调控脑tau病理和功能损伤的机制；干预AMPK改善模型鼠AD样tau病理和脑功能损伤的效果评价，研究为早期防治AD提供基础研究资料。

AMPK作为细胞能量代谢的感受分子，调节细胞的能量代谢平衡，其功能异常参与代谢相关疾病的发生，如糖尿病、动脉粥样硬化及神经推行性疾病（AD），也是这些疾病发生的重要分子交汇点。因此，阐明AMPK在AD发病中的作用和机制，对理解能量平衡障碍引起脑功能损伤和增加AD风险具有理论指导，同时也为以AMPK为分子靶点开发新的AD诊疗药物提供新策略。研究证明1）AMPK的表达和活性依赖性磷酸化水平降低，在APP/PS1 转基因AD模型鼠，代谢相关AD模型和CB1 KO小鼠模型，而且在野生型小鼠呈现年龄依赖性。2）AMPK活性降低与tau病理改变，包括p-tau水平和乙酰化水平呈现正相关性在APP/PS1转基因小鼠、CB1 KO小鼠及STZ诱导的代谢相关AD模型。 3）在APP/PS1、STZ和CB1 KO小鼠不同实验AD动物模型进行AMPK干预实验。通过AAV或化学药物介导的AMPK过表达/下调或激活/抑制，可以有效的逆转两种动物模型的AD样病理变化，包括降低p-tau, ac-tau水平和增加Aβ降解，同时改善模型鼠的学习记忆损伤。4）AMPK调节ptau和tau乙酰化修饰的机制研究证明AMPK调节ptau和tau乙酰化分别通过GSKβ和Sirt1参加。5）AMPK对Aβ降解的调节作用，初步的研究提示AMPK激活可以降低Aβ1-42通过激活ACE和IDE。课题通过不同动物和细胞模型发现AMPK活性的降低与脑AD样病理损伤和脑学习记忆降低，其机制通过调节GSKβ, Sirt1, ACE和IDE, 证明AMPK参与AD发生和发展，是一个很好的潜在AD诊疗的靶分子。未来的研究应当阐明AMPK活性调节反应异常的机制，这样有助于解释AMPK药物反应性降低及不同AMPK药物诊疗产生不同结果的原因。