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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 play an important role in the formation of synapses, but it is unclear how astroglial protrusions associate with synaptic structures during development. This article analyzes the types of Bergmann glia (BG) neurite outgrowth during cerebellar synapses. This paper found that in this process, the outgrowth of BG protuberances is associated with the coating of dendritic spines. In addition, two-photon time-resolved imaging showed that BG protrusions are highly dynamic and tend to stabilize during echinodesis. Although synaptic activity depends on the actin polymerization, the activities of the cytoskeleton regulators Rac1 and RhoG do not play a role in the motility or density of glial processes, but rather are crucial for maintaining the length of the processes. This article extends this discovery to explore the relationship between the morphology of the protrusions and the coating and to find that the shortened protrusions result in a reduction in the coverage of the spines. We further find that in areas where BG expresses dn-Rac1 and low levels of synaptic coating, an increase in the number of synapses is shown. These analyzes suggest how BG protrusions grow and surround the synapse structure, elucidate the importance of the BG protrusion structure for the proper development of synaptic sheath, and suggest the role of the coating in synaptic formation.