PKD1调控tau蛋白聚集及外泌体依赖的tau传播机制研究

Tau蛋白异常聚集和传播是导致阿尔茨海默病（AD）患者认知功能受损的重要原因，然而其分子机制尚不明确。申请者在前期研究中发现：蛋白激酶D1（PKD1）激活并结合tau蛋白，可能是引起tau过度磷酸化和外泌体依赖性tau传播的重要原因。本项目将从分子、细胞和动物三个层面，研究PKD1对tau病变过程的调控机制：通过质谱和点突变技术探究PKD1-tau结合的分子基础；采用转基因小鼠研究PKD1对tau聚集、突触可塑性和认知功能等关键生理病理过程的作用。采用外泌体分析技术在原代神经元中探讨二酰甘油-PKD1-外泌体通路对tau的质膜转位和外泌体依赖性释放的作用；并进一步在C57小鼠内嗅皮层-海马tau传播模型中研究PKD1对脑内tau传播的调控机制。基此，本项目拟探索干预PKD1-tau结合对tau聚集、tau释放和传播、及认知功能障碍的挽救效果，揭示AD的新病理机制，为AD防治提供新分子靶标。

Abnormal tau accumulation and propagation contribute to cognitive impairments in patients with Alzheimer's disease (AD). However, the underlying mechanisms of tau accumulation and propagation remain to be elucidated. Our primary results revealed that neuronal PKD1 activation and PKD1-tau protein interaction contribute to both tau hyperphosphorylation and exosome-dependent tau propagation. In the present study, the molecular basis of PKD1-tau interaction will be further explored through mass spectrometry and point mutation technology, and the crucial effect of PKD1 on tau aggregation, synaptic plasticity and cognitive function will be studied in transgenic mice. The mechanisms of tau plasma membrane translocation and exosome-dependent tau release mediated by DAG-PKD1-exosome pathway will be explored in primary neurons, and the function of PKD1 on regulating tau propagation will be verified in an in vivo entorhinal cortex-hippocampus tau propagation model. Based on above, we will explore the attenuating effects of disrupting the PKD-tau interaction on tau aggregation, tau release and propagation, and cognitive dysfunction, to bring new insights into the pathological mechanisms of AD, and provide novel molecular targets for AD prevention and treatment.