PDF(Pubmed)
Abstract：
A primary cilium is a thin membrane-bound extension off a cell surface that contains receptors for perceiving and transmitting signals that modulate cell state and activity. While many cell types have a primary cilium, little is known about primary cilia in the brain, where they are less accessible than cilia on cultured cells or epithelial tissues and protrude from cell bodies into a deep, dense network of glial and neuronal processes. Here, we investigated cilia frequency, internal structure, shape, and position in large, high-resolution transmission electron microscopy volumes of mouse primary visual cortex. Cilia extended from the cell bodies of nearly all excitatory and inhibitory neurons, astrocytes, and oligodendrocyte precursor cells (OPCs), but were absent from oligodendrocytes and microglia. Structural comparisons revealed that the membrane structure at the base of the cilium and the microtubule organization differed between neurons and glia. OPC cilia were distinct in that they were the shortest and contained pervasive internal vesicles only occasionally observed in neuron and astrocyte cilia. Investigating cilia-proximal features revealed that many cilia were directly adjacent to synapses, suggesting cilia are well poised to encounter locally released signaling molecules. Cilia proximity to synapses was random, not enriched, in the synapse-rich neuropil. The internal anatomy, including microtubule changes and centriole location, defined key structural features including cilium placement and shape. Together, the anatomical insights both within and around neuron and glia cilia provide new insights into cilia formation and function across cell types in the brain.
摘要：
初级纤毛是细胞表面的薄膜结合延伸,其含有用于感知和传递调节细胞状态和活性的信号的受体。虽然许多细胞类型都有初级纤毛，对大脑中的初级纤毛知之甚少，在培养细胞或上皮组织上，它们比纤毛更难以接近，并从细胞体突出到深处，神经胶质和神经元过程的密集网络。这里,我们调查了纤毛频率,内部结构,形状,和大的位置，小鼠初级视觉皮层的高分辨率透射电子显微镜体积。纤毛从几乎所有兴奋性和抑制性神经元的细胞体中延伸出来，星形胶质细胞,和少突胶质细胞前体细胞（OPC），但少突胶质细胞和小胶质细胞不存在。结构比较表明，神经元和神经胶质之间纤毛和微管组织底部的膜结构不同。OPC纤毛的独特之处在于它们最短，并且仅在神经元和星形胶质细胞纤毛中偶尔观察到普遍存在的内部囊泡。调查纤毛近端特征显示，许多纤毛与突触直接相邻，表明纤毛已经准备好遇到局部释放的信号分子。纤毛接近突触是随机的，不丰富，在富含突触的神经纤维里.内部解剖学，包括微管变化和中心位置，定义的关键结构特征，包括纤毛位置和形状。一起,神经元和神经胶质纤毛内部和周围的解剖学见解提供了对脑内纤毛形成和功能的新见解。
