Role of polysialic acid for cortical interneuron migration and dissection of defective brain development in polysialic acid-deficient mice by conditional knock-out of St8sia2

聚唾液酸对皮质中间神经元迁移的作用以及条件性敲除 St8sia2 的聚唾液酸缺陷小鼠大脑发育缺陷的解剖

• 批准号: 269703561
• 负责人: Professor Dr. Herbert Hildebrandt
• 金额: --
• 依托单位: Institut für Klinische Biochemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/269703561?language=en
• 关键词: Role; polysialic; acid; cortical; interneuron

The neural cell adhesion molecule NCAM and its modification with the sugar polymer polysialic acid (polySia) are major determinants of brain development. PolySia is synthesized by the polysialyltransferases ST8SIA2 and ST8SIA4, which are independently regulated but often co-expressed in the same cell. In mice, ST8SIA2 seems to be the major polysialyltransferase during development, whereas ST8SIA4 prevails in the adult brain. Ablation of both enzymes generated mice that are completely devoid of polySia. These mice reproduce defects of the polySia- and NCAM-depleted Ncam-/- mice, but also show damage of major brain axon tracts, which can be rescued by additional deletion of the polySia carrier protein NCAM. Guided by the severe phenotype of the St8sia2, St8sia4 double knockout mice, we started to comparatively re-evaluate the two single knockout lines. Deficits of thalamocortical connectivity were found specifically in the St8sia2-/- line and may be linked to the observed cognitive impairments. In contrast, both lines displayed reduced interneuron densities in the prefrontal cortex as well as signs of impaired interneuron migration from the medial ganglionic eminence (MGE) into the cortex during embryonic development. Lines of polySia-deficient, GAD67-GFP transgenic mice with genetically labeled interneurons have been established with the aim to study the cellular and molecular mechanisms of polySia-dependent cortical interneuron development in vivo as well as in slice culture and MGE-cortex co-culture systems. High resolution time lapse imaging of GFP-labelled cells in these cultures will be used to study the impact of polySia expression on the dynamics of interneuron migration and on the response to motogenic factors. Other objectives of the current proposal are the dissection of mechanisms which lead to disturbed thalamus-cortex connectivity and interneuron deficits in the prefrontal cortex of St8sia2-/- mice. 'Floxed' St8Sia2Fx/Fx mice have been generated and have been crossed with lines expressing the Cre-recombinase under the Lhx6 promoter or under the Foxb1 promoter for specific deletion of St8Sia2 in MGE-derived cortical interneurons or in the developing thalamus, but not cortex. The interneuron-specific knockout will reveal cell-autonomous consequences of polySia-deficiency. Similarly, the thalamus-specific deletion will allow us to distinguish between the role of polySia on thalamocortical axons and polySia present in their environment. Deviant development due to loss of polySia from the thalamocortical but not the corticothalamic axons may shed light on longstanding questions over the mutual impact of these fibers in development. Finally, comparing behavioral traits between mice with thalamocortical or interneuron deficits, or both, will enable the assignment of defined neurodevelopmental defects to specific cognitive functions.

神经细胞粘附分子NCAM及其与糖聚合物聚唾液酸（polySia）的修饰是大脑发育的主要决定因素。PolySia是由多唾液基转移酶ST8SIA2和ST8SIA4合成的，它们是独立调控的，但经常在同一细胞中共表达。在小鼠中，ST8SIA2似乎是发育过程中主要的多唾液基转移酶，而ST8SIA4在成年大脑中普遍存在。这两种酶的消融产生了完全缺乏多囊性贫血的小鼠。这些小鼠复制了polySia-和Ncam-缺失的Ncam-/-小鼠的缺陷，但也表现出主要脑轴突束的损伤，这可以通过额外缺失polySia载体蛋白Ncam来修复。在St8sia2、St8sia4双敲除小鼠严重表型的指导下，我们开始对这两个单敲除系进行比较重新评价。丘脑皮质连通性缺陷在St8sia2-/-系中被发现，可能与观察到的认知障碍有关。相比之下，这两种系在胚胎发育过程中表现出前额叶皮层中间神经元密度降低，以及中间神经元从内侧神经节隆起（MGE）向皮层迁移受损的迹象。建立了具有遗传标记中间神经元的多囊症缺失、GAD67-GFP转基因小鼠系，目的是研究多囊症依赖的皮层中间神经元在体内以及在薄片培养和mge -皮层共培养系统中的细胞和分子机制。这些培养物中gfp标记细胞的高分辨率延时成像将用于研究polySia表达对神经元间迁移动力学和对运动因子的反应的影响。当前提案的其他目标是解剖导致St8sia2-/-小鼠丘脑皮层连接紊乱和前额叶皮层中间神经元缺陷的机制。已经产生了“Floxed”St8Sia2Fx/Fx小鼠，并与在Lhx6启动子或Foxb1启动子下表达Cre-recombinase的细胞系杂交，以特异性删除mge衍生的皮质中间神经元或发育中的丘脑中的St8Sia2，而不是皮质中的St8Sia2。神经元间特异性敲除将揭示多晶硅缺乏症的细胞自主后果。同样，丘脑特异性缺失将使我们能够区分丘脑皮质轴突上的polySia和其环境中存在的polySia的作用。由于丘脑皮质而非皮质丘脑轴突的polySia缺失而导致的异常发育可能揭示了这些纤维在发育过程中相互影响的长期问题。最后，比较具有丘脑皮质或中间神经元缺陷的小鼠的行为特征，或两者兼而有之，将能够将定义的神经发育缺陷分配到特定的认知功能。

项目成果

Polysialylation at Early Stages of Oligodendrocyte Differentiation Promotes Myelin Repair

• DOI: 10.1523/jneurosci.1147-17.2017
• 发表时间: 2017-08
• 期刊: The Journal of Neuroscience
• 作者: Sebastian Werneburg;Hazel L S Fuchs;I. Albers;H. Burkhardt;V. Gudi;T. Skripuletz;M. Stangel;R. Gerardy-Schahn;H. Hildebrandt

Effects of the Genetic Depletion of Polysialyltransferases on the Structure and Connectivity of Interneurons in the Adult Prefrontal Cortex

• DOI: 10.3389/fnana.2019.00006
• 发表时间: 2019-02-06
• 期刊: FRONTIERS IN NEUROANATOMY
• 影响因子: 2.9
• 作者: Curto, Yasmina;Alcaide, Julia;Nacher, Juan
• 通讯作者: Nacher, Juan

Deficits of olfactory interneurons in polysialyltransferase‐ and NCAM‐deficient mice

聚唾液酸转移酶â和NCAMâ缺陷小鼠的嗅觉中间神经元缺陷

• DOI: 10.1002/dneu.22324
• 发表时间: 2016
• 期刊: Developmental Neurobiology
• 影响因子: 3
• 作者: Röckle I;Hildebrandt H
• 通讯作者: Hildebrandt H

Transgenic overexpression of polysialyltransferase ST8SiaIV under the control of a neuron-specific promoter does not affect brain development but impairs exploratory behavior

• DOI: 10.1093/glycob/cwz040
• 发表时间: 2019-09-01
• 期刊: GLYCOBIOLOGY
• 影响因子: 4.3
• 作者: Fewou, Simon Ngamli;Roeckle, Iris;Eckhardt, Matthias
• 通讯作者: Eckhardt, Matthias