内质网至高尔基体运输网络在神经发育中的重要功能及机制研究

The anterograde transport from ER to Golgi apparatus is essential for neural development. Meningioma Expressed Antigen 6 (MEA6), an ER membrane protein, plays an important role in the transport of collagen and VLDL. Mutation of MEA6 is associated with Fahr’s disease. However, the role of MEA6 in neural development is still unknown..We generated mice with conditional knockout of Mea6 in the brain (cKO mice), and found that cKO mice were lethal around postnatal 21 days, which could be rescued by expression of human MEA6. We found that MEA6 is primarily located in the ER exit site, ER-Golgi intermediate compartment (ERGIC) and Golgi apparatus. Through the quantitative mass-spec analysis, we observed that many proteins associated with the structure and function of ER and Golgi apparatus, and some ion channel proteins and receptors were down-regulated in the cerebral cortex of cKO mice. We hypothesize that MEA6 is involved in the vesicle transportation during brain development. In order to test this hypothesis, we will study the processes of neural development and synapse formation, vesicle formation and transport, the integrity of the organelles, using cellular and molecular techniques both in vivo and in vitro, in Mea6 cKO mouse model. Finally, the in vivo function of MEA6 will be investigated through electrophysiology and behavior tests. Further study of MEA6 function would help us to learn more about the roles of ER to Golgi transport pathway and the pathogenesis of associated diseases.

内质网至高尔基体的正向囊泡运输为神经系统的发育，尤其是形态发生提供了保障。MEA6是一个内质网膜蛋白，在胶原蛋白和低密度脂蛋白的运输中起着重要的作用。另外，MEA6突变可能与Fahr’s disease的发病相关，但是其在神经发育中的功能还未知。.我们在大脑中条件性敲除Mea6的小鼠，发现该小鼠出生后出现运动功能障碍。MEA6蛋白主要定位于内质网释放位点上，也有部分定位在内质网高尔基体中间体，以及高尔基体上。定量质谱结果表明，Mea6敲除小鼠大脑皮层中，与内质网和高尔基体的结构和功能相关的蛋白，还有一些离子通道蛋白与细胞膜受体表达下调。我们推测Mea6可能通过囊泡运输，参与神经形态发生和突触囊泡的形成。为了验证该假设，我们将利用Mea6敲除小鼠模型，研究神经形态发生与突触形成过程；突触小泡的形成和运输；以及细胞器的整体连续性是否发生异常，最后将通过电生理和行为学实验进行功能验证。

内质网至高尔基体的正向囊泡运输为神经系统的发育，尤其是形态发生提供了保障。MEA6是一个内质网膜蛋白，在胶原蛋白和低密度脂蛋白的运输中起着重要的作用。我们在大脑中条件性敲除Mea6，发现该小鼠出生后出现运动功能障碍，小鼠在出生后21天左右死亡。定量质谱结果表明，Mea6敲除小鼠大脑皮层中，与内质网和高尔基体的结构和功能相关的蛋白，还有一些离子通道蛋白与细胞膜受体表达下调。免疫荧光染色证明MEA6蛋白主要定位于内质网释放位点上，也有部分定位在内质网高尔基体中间体，以及高尔基体上。Mea6蛋白功能缺失通过影响囊泡的正向运输，以及细胞器的整体连续性，从而影响了神经形态发生和突触囊泡的形成，并最终影响了小鼠的行为学。人源化的hMea6转基因小鼠能够挽救Mea6基因敲除小鼠的表型。