Institut Pasteur, Unit of Technology and Service Ultra-structural Bio-Imaging, 28 rue du Docteur Roux, 75015, Paris, France.
Institut Pasteur, Membrane Traffic and Pathogenesis, 28 rue du Docteur Roux, 75015, Paris, France.
Nat Commun. 2019 Jan 21;10(1):342. doi: 10.1038/s41467-018-08178-7.
The orchestration of intercellular communication is essential for multicellular organisms. One mechanism by which cells communicate is through long, actin-rich membranous protrusions called tunneling nanotubes (TNTs), which allow the intercellular transport of various cargoes, between the cytoplasm of distant cells in vitro and in vivo. With most studies failing to establish their structural identity and examine whether they are truly open-ended organelles, there is a need to study the anatomy of TNTs at the nanometer resolution. Here, we use correlative FIB-SEM, light- and cryo-electron microscopy approaches to elucidate the structural organization of neuronal TNTs. Our data indicate that they are composed of a bundle of open-ended individual tunneling nanotubes (iTNTs) that are held together by threads labeled with anti-N-Cadherin antibodies. iTNTs are filled with parallel actin bundles on which different membrane-bound compartments and mitochondria appear to transfer. These results provide evidence that neuronal TNTs have distinct structural features compared to other cell protrusions.
细胞间通讯的协调对于多细胞生物至关重要。细胞间通讯的一种机制是通过长而富含肌动蛋白的膜状突起，称为隧道纳米管（TNTs），它允许各种货物在体外和体内的远距离细胞质之间进行细胞间运输。由于大多数研究未能确定其结构特征并检查它们是否真正是无末端的细胞器，因此需要在纳米分辨率下研究 TNTs 的解剖结构。在这里，我们使用相关的 FIB-SEM、光镜和冷冻电镜方法来阐明神经元 TNTs 的结构组织。我们的数据表明，它们由一束由抗 N-钙粘蛋白抗体标记的线连接在一起的开放式个体隧道纳米管（iTNTs）组成。iTNTs 内充满了平行的肌动蛋白束，不同的膜结合区室和线粒体似乎在其上转移。这些结果提供了证据，表明神经元 TNTs 与其他细胞突起具有明显不同的结构特征。
