摘要
星形胶质细胞在突触形成中发挥重要作用,但星形胶质细胞突起如何在发育过程中与突触结构相联系还不是很清楚。本文分析在小脑突触发生过程中Bergmann胶质细胞(BG)突起生长的类型。本文发现在这个过程中,BG突起向外生长与树突棘增多的包被作用相关。此外,双光子时间分辩显像显示BG突起是高度动态的,在棘包被过程中突起趋于稳定。虽然突触活力依赖于肌动蛋白的聚合作用,但细胞骨架调节器Rac1和RhoG的活动在胶质细胞突起的动力或密度上并未发挥作用,而是对于保持突起长度起关键性作用。本文扩展这个发现,探查突起形态和包被之间的关系,发现缩短的突起导致棘覆盖的减少。本文进一步发现在BG表达dn-Rac1和低水平突触包被的区域,显示突触数量的增加。这些分析提示BG突起如何生长并包围突触结构,阐明BG突起结构对突触包被适当发育的重要性,并提示包被在突触形成中的作用。
Astrocytes have an important role in synaptic formation and function but how astrocytic processes become associated with synaptic structures during development is not well understood.Here we analyzed the pattern of growth of the processes extending off the main Bergmann glial（BG） shafts during synaptogenesis in the cerebellum.We found that during this period,BG process outgrowth was correlated with increased ensheathment of dendritic spines.Inaddition,two-photon time-lapse imaging revealed that BG processes were highly dynamic,and processes became more stable as the period of spine ensheathment progressed.While process motility was dependent on actin polymerization,activity of cytoskeletal regulators Rac1 and RhoG did not play a role in glial process dynamics or density,but was critical for maintaining process length.We extended this finding to probe the relationship between process morphology and ensheathment,finding that shortened processes result in decreased coverage of the spine.Furthermore,we found that areas in which BG expressed dn-Rac1,and therefore had a lower level of synaptic ensheathment,showed an overall increase in synapse number.These analyses reveal how BG processes grow to surround synaptic structures,elucidate the importance of BG process structure for proper development of synaptic ensheathment,and reveal a role for ensheathment in synapse formation.V 2008 Wiley-Liss,Inc.
出处
《神经损伤与功能重建》
2008年第5期328-341,共14页
Neural Injury and Functional Reconstruction
基金
Whitehall Foundation and NINDS(1R01NS057667)
