EO-FAD和LOAD小鼠模型的构建及其原代神经细胞中TYROBP对Tau蛋白磷酸化的影响研究

TYROBP, expressed mainly in microglia in the brain, was reported to be a key regulator in late-onset Alzheimer’s disease, while the relationship between TYROBP and Tau hyperphosphorylation has not been demonstrated. Our prior work has shown the mutation of PSEN1 p.G378E in one Chinese early-onset familial Alzheimer’s disease (EO-FAD) families. Neuron loss, gliosis, SPs, NFTs and neuropil were all observed microscopically in the brain of the proband. In order to investigate the relationship between TYROBP and Tau hyperphosphorylation and whether they play the same role in EO-FAD and LOAD, PSEN1G378E/TYROBP-/- double transgenic mouse model and ICV-STZ/TYROBP-/- mouse model will be established. Furthermore, in order to investigate the possible molecular mechanisms, TREM2/TYROBP—TLR2/4/9—NFκB/MAP/GSK3/JAK—IL-1β/IL-6/TNF-α, TREM2/TYROBP—Syk—Pyk2/CaMK—NFAT and IL-1R/IL-6R/TNFR—p38MAPK/CDK5/GSK3β pathways will be studied in primary cultured microglia cells and neurons, respectively. The present study will help us to understand the pathogenesis of AD and may provide potential targets for treatment of AD.

TYROBP是2013年发现的与LOAD具有明显相关性的基因，在脑内主要表达于小胶质细胞，其与Tau过磷酸化的关系尚无报道。前期研究工作中我们在一个EO-FAD家系发现了PSEN1 p.G378E突变，对先证者进行尸检，结果发现胶质细胞激活及Tau蛋白过磷酸化。为了研究TYROBP对Tau过磷酸的影响及其在EO-FAD和LOAD中发挥的作用，我们拟在前期研究工作基础上构建PSEN1G378E/TYROBP-/-和ICV-STZ/TYROBP-/-小鼠模型，并进一步原代培养其小胶质细胞和神经元，运用信号通路PCR芯片筛选出小胶质细胞内炎性因子释放的可能通路及神经元内炎性因子导致Tau过磷酸化的可能通路，最终运用Western Blots进行验证。研究结果可帮助我们理解AD的发病机制，可能为AD的治疗提供新的靶点。

阿尔茨海默病（Alzheimer disease，AD）是最常见的痴呆类型，临床表现为记忆力逐渐下降、高级认知功能逐渐丧失，病理学表现老年斑（主要成分是Aβ）和神经纤维缠结（主要成分是磷酸化的Tau）为主，目前尚无有效的疾病修饰药物。TYROBP是2013年发现的与LOAD具有明显相关性的基因，其与Tau过磷酸化的关系尚无报道，我们运用TYROBP KO(基因敲除)、PSEN1 G378E KI（基因突变）小鼠从分子水平研究TYROBP与Tau过磷酸化的关系，结果发现，TYROBP KO可直接导致小胶质细胞、星形胶质细胞激活；总Tau表达水平升高、Tau多个位点磷酸化（Ser202, Thr205、T181、T231），且发现Tau蛋白磷酸化是通过CDK5/ERK/GSK3β信号通路所致。研究结果可帮助我们理解AD的发病机制，所以TYROBP蛋白可能做为新的治疗靶点。

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