Tunneling nanotubes (TNTs) are thin intercellular connections that facilitate the transport of diverse cargoes, ranging from ions to organelles. While TNT studies have predominantly been conducted in cell cultures, the existence of open-ended TNTs within live organisms remains unverified. Despite the observation of intercellular connections during embryonic development across various species, their functional role in facilitating material transfer between connected cells has not been confirmed. In this study, we performed mosaic labeling of gastrula cells in zebrafish embryos to demonstrate the coexistence of TNT-like structures alongside other cellular protrusions. These embryonic TNT-like connections exhibited a morphology similar to that of TNTs described in cell culture, appeared to have similar formation mechanisms, and could be induced by Eps8 overexpression and CK666 treatment. Most notably, we demonstrated their capability to transfer both soluble cargoes and organelles, thus confirming their open-endedness. This study demonstrates the existence of functional, open-ended TNTs in a living embryo.

中文翻译：

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隧道式纳米管可在斑马鱼胚胎中实现细胞间转移


隧道纳米管 （TNT） 是薄的细胞间连接，可促进从离子到细胞器的各种货物的运输。虽然 TNT 研究主要在细胞培养物中进行，但活体生物体内是否存在开放式 TNT 仍未得到证实。尽管在各种物种的胚胎发育过程中观察到细胞间连接，但它们在促进连接细胞之间物质转移方面的功能作用尚未得到证实。在这项研究中，我们对斑马鱼胚胎中的原肠胚细胞进行了马赛克标记，以证明 TNT 样结构与其他细胞突起共存。这些胚胎 TNT 样连接表现出与细胞培养中描述的 TNT 相似的形态，似乎具有相似的形成机制，并且可以由 Eps8 过表达和 CK666 处理诱导。最值得注意的是，我们证明了它们转移可溶性货物和细胞器的能力，从而证实了它们的开放性。本研究证明了活胚胎中存在功能性的开放式 TNT。