C1型尼曼-匹克氏症轴突发育异常的病理机制

Niemann-Pick disease type C1 (NPD) is neurological genetic disease caused by mutation in the NPC1 gene, resulting in abnormal accumulation of lipids in the neurons. Until now, the pathological mechanism of this disease is still unknown and there is no effective treatment for this disease. Our preliminary data have shown that axonal growth is defected, and therefore, in this presented proposal, we will focus on the function of NPC1 in the axonal growth and investigate mechanisms involving in anatomical alteration and endogenous gene regulation during the early pathological stage of NPD. In present project, we will use different advanced bio-techniques, such as gene transfection, fluorescent tracer, electron microscope, confocal scanning microscope, living cell imaging and patch clamp, in the in vivo NPC1 mutant mouse model and in vitro cell culture. The findings in this study will help understand pathological effects and mechanisms of NPD in the developing central nerve system and provide basic research data for the potential clinic treatment of NPD.

C1 型尼曼-匹克氏症（Niemann-Pick disease type C1, NPD）是一种遗传性的，由于NPC1基因突变而引起的神经元脂质储积病。因其发病机制并不清楚，导致目前临床上还没有找到有效的治疗方法。本项目是在NPD小鼠轴突发育异常的前期实验基础上，研究NPC1基因对神经元轴突的影响。我们将利用多种现代生物学前沿技术，如基因转染、免疫荧光示踪、扫描电镜、活细胞成像和多通道膜片钳等技术，结合体内外实验（in vivo and in vitro），从形态学变化和内源性基因调控两个方面系统分析NPC1突变对轴突发育的影响，揭示NPD病变发生的分子机制，为进一步的研究和临床治疗提供基础性资料。

本课题通过免疫组化、神经元分离培养、神经纤维示踪、qRT-PCR、Western blot等技术，从形态学差异和内源性基因调控两个方面研究NPC1突变对轴突发育的影响，揭示NPD病变发生的分子机制。通过我们的研究发现：（1）NPC1基因突变抑制神经元突起的发育；（2）NPC1基因突变降低神经元的分支复杂性，影响突起的形态；（3）NPC1基因突变引起胆固醇在胞体中聚集，影响PSD95蛋白的表达，导致神经元轴突发育受损；（4）NPC1神经元突起脂筏中的胆固醇水平明显降低，导致突触的分布和形态改变，影响神经元的突触传递；（5）对NPC1鼠脑进行生物信息学分析，证实miRNAs表达发生变化并参与到髓鞘形成过程的调控。综合以上结果，证实NPC1基因突变影响了轴突发育和突触传递，这将为神经系统疾病的早期预防和治疗提供理论依据。