阿尔茨海默病（AD）是危害人类健康的重大疾病。铜暴露是促发AD的关键环境因素。铜暴露（尤其低剂量）对AD特征性病变-凋亡性神经退化的影响未见报道。本课题组前期研究发现：低剂量慢性铜暴露诱导AD神经退化，上调tubby转录因子及miR-195；抑制tubby下调miR-195表达，抑制miR-195显著改善铜致AD神经退化。生物信息学分析发现，tubby与pre-miR-195，miR-195与经典瞬时受体电位通道蛋白1（TRPC1）基因均存在结合位点。因此，我们推测：低剂量铜暴露，通过增加脑内tubby/pre-miR-195基因启动子的结合， 上调miR-195表达，miR-195靶向下调TRPC1表达，激发内质网应激，导致AD神经退化。本项目拟采用基因长效抑制和过表达、染色质免疫共沉淀等手段，阐明低剂量铜暴露促进AD神经退化的表观遗传学调控机制，为AD的防治提供新的策略和药物开发靶点。

Alzheimer’s disease (AD) is a common neurodegenerative disease with severe health impact. Copper may be a key environmental factor contributing to the development of AD. However, the effects of copper exposure (especially low-dose) on AD characteristic pathology-apoptotic neurodegeneration remain elusive. Our preliminary study has demonstrated that trace amount of copper in drinking water (below the copper standard in drinking water set by The U.S. Environmental Protection Agency) caused apoptotic neurodegeneration of hippocampal neurons of AD transgenic mice with concurrent up-regulation of transcriptional factor tubby and miR-195. Inhibition of tubby down-regulated the expression of miR-195, and inhibition of miR-195 expression prevented neurodegeneration in AD caused by low-dose chronic copper exposure. Informatics analysis revealed that there are binding sites between tubby and pre-miR-195 gene, and transient receptor potential canonical type 1 (TRPC1) may be an ideal target gene of miR-195. These findings lead us to raise a hypothesis as follows: low-dose chronic copper exposure may promote the binding of tubby with promoter of pre-miR-195 gene, and therefore up-regulate the expression of miR-195; the latter would down-regulate the expression of its target gene TRPC1, thereby triggering endoplasmic reticulum (ER) stress. ER stress would therefore result in neurodegeneration in AD. We will use the techniques such as recombinant adeno-associated virus (rAAV)-mediated long-term silencing and over-expression of genes and chromatin immunoprecipitation to elucidate the epigenetic regulatory mechanisms by which copper exposure caused neurodegeneration in AD. The accomplishment of this project would be expected to provide new strategies for the prevention and treatment of AD as well as novel molecular targets for the development of AD drugs.