Institut Pasteur, Université Paris Cité, CNRS UMR 3691, Membrane Traffic and Pathogenesis, Paris, France.
Université Paris Saclay, Gif-sur-Yvette, Paris, France.
Cell Death Dis. 2023 May 18;14(5):329. doi: 10.1038/s41419-023-05835-8.
Tunnelling Nanotubes (TNTs) facilitate contact-mediated intercellular communication over long distances. Material transfer via TNTs can range from ions and intracellular organelles to protein aggregates and pathogens. Prion-like toxic protein aggregates accumulating in several neurodegenerative pathologies, such as Alzheimer's, Parkinson's, and Huntington's diseases, have been shown to spread via TNTs not only between neurons, but also between neurons-astrocytes, and neurons-pericytes, indicating the importance of TNTs in mediating neuron-glia interactions. TNT-like structures were also reported between microglia, however, their roles in neuron-microglia interaction remain elusive. In this work, we quantitatively characterise microglial TNTs and their cytoskeletal composition, and demonstrate that TNTs form between human neuronal and microglial cells. We show that α-Synuclein (α-Syn) aggregates increase the global TNT-mediated connectivity between cells, along with the number of TNT connections per cell pair. Homotypic TNTs formed between microglial cells, and heterotypic TNTs between neuronal and microglial cells are furthermore shown to be functional, allowing movement of both α-Syn and mitochondria. Quantitative analysis shows that α-Syn aggregates are transferred predominantly from neuronal to microglial cells, possibly as a mechanism to relieve the burden of accumulated aggregates. By contrast, microglia transfer mitochondria preferably to α-Syn burdened neuronal cells over the healthy ones, likely as a potential rescue mechanism. Besides describing novel TNT-mediated communication between neuronal and microglial cells, this work allows us to better understand the cellular mechanisms of spreading neurodegenerative diseases, shedding light on the role of microglia.
隧道纳米管 (TNTs) 促进了长距离的细胞间接触介导的通讯。通过 TNTs 的物质转移范围从离子和细胞内细胞器到蛋白质聚集体和病原体。在几种神经退行性疾病中积累的类朊病毒毒性蛋白聚集体,如阿尔茨海默病、帕金森病和亨廷顿病,已经被证明可以通过 TNTs 在神经元之间传播,也可以在神经元-星形胶质细胞和神经元-周细胞之间传播,这表明 TNTs 在介导神经元-胶质细胞相互作用中的重要性。也有报道称在小胶质细胞之间存在 TNT 样结构,然而,它们在神经元-小胶质细胞相互作用中的作用仍不清楚。在这项工作中,我们定量表征了小胶质细胞 TNTs 及其细胞骨架组成,并证明 TNTs 可以在人神经元和小胶质细胞之间形成。我们表明,α-突触核蛋白 (α-Syn) 聚集体增加了细胞间的整体 TNT 介导的连接,以及每个细胞对的 TNT 连接数。还显示小胶质细胞之间形成同源 TNTs,神经元和小胶质细胞之间形成异源 TNTs 是功能性的,允许 α-Syn 和线粒体的运动。定量分析表明,α-Syn 聚集体主要从神经元转移到小胶质细胞,这可能是一种减轻积累聚集体负担的机制。相比之下,小胶质细胞更倾向于将线粒体转移到受 α-Syn 影响的神经元细胞,而不是健康的神经元细胞,这可能是一种潜在的挽救机制。除了描述神经元和小胶质细胞之间新的 TNT 介导的通讯外,这项工作使我们能够更好地理解神经退行性疾病传播的细胞机制,揭示小胶质细胞的作用。