Claudin-5a在斑马鱼中枢神经系统屏障形成中的作用与机制研究

血液脑脊液、血脑屏障等中枢神经系统屏障对维持脑组织正常的生理功能至关重要，但领域内对其发育调控网络特别是血液脑脊液屏障及其主要结构单元脉络丛的功能形成机制仍知之甚少。我们前期研究发现，斑马鱼紧密连接蛋白Claudin-5a (Cldn5a)在脑血管内皮细胞和脉络丛上皮细胞中均有表达；敲除cldn5a后的斑马鱼在亚成鱼阶段呈现脑水肿及脊椎弯曲等中枢神经系统缺陷，预示其在血脑屏障和血液脑脊液屏障形成和功能维持中的重要作用。本课题拟结合体内外屏障功能分析、cldn5a内皮特异性拯救等遗传学手段分别探讨Cldn5a在血脑屏障（内皮屏障）与血液脑脊液屏障（上皮屏障）中的功能；重点研究Cldn5a的缺失对脑血管内皮和脉络丛上皮细胞间连接结构和功能的影响；同时探讨Cldn5a在脉络丛上皮细胞极性维持、游离端微绒毛功能等中的作用。本研究将为血液脑脊液等中枢神经系统屏障的形成和稳态维持机制提供更深入的认识。

The central nervous system (CNS) is protected by several specialized barriers such as blood-cerebrospinal fluid barrier (BCSFB) and blood-brain barrier (BBB). However, little is known about the developmental mechanisms of the CNS barriers, especially the BCSFB and its main structural unit of choroid plexus (ChP). Our primary studies revealed that as one of the essential tight junction proteins, zebrafish Claudin-5a (Cldn5a) was expressed in both cerebrovascular endothelial cells and the epithelial cells of ChP. Knock out of cldn5a caused severe CNS defects in zebrafish juveniles, such as brain edema and bent spinal cord, indicating an involvement of Cldn5a on the functional formation and maintenance of BBB and BCSFB. In this study, we will apply the barrier function analyses assay and tissue specific rescue of cldn5a strategies etc. to investigate the developmental roles of Cldn5a on both the BBB (endothelial barrier) and the BCSFB (epithelial barrier), with a special focus on the stucture and function of the ChP epithelial cells and the vascular endothelial cells after loss of Cldn5a. We will also study the epithelial cell polarity maintenance and the microvillus functions of ChP in the cldn5a mutant. Our study will extend the scientific knowledges of the functional formation and physiological functions of CNS barriers such as BCSFB.