Sun Yanli, Zhang Huikai, Zavodnik Ilya B, Zhao Hucheng, Feng Xiqiao
Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, School of Aerospace Engineering, Tsinghua University, Beijing, 100084, China.
Department of Biochemistry, Yanka Kupala State University of Grodno, 230030, Grodno, Belarus.
Heliyon. 2024 Aug 15;10(17):e36265. doi: 10.1016/j.heliyon.2024.e36265. eCollection 2024 Sep 15.
Tunneling nanotubes (TNTs) that connect cells have been recognized as a pathway for long-range intercellular transport of diverse cargoes, including viruses, lysosomes or other organelles, Ca and electrical signals. TNTs can initially be formed from thin finger-like actin assembly-driven protrusions or cell contacts and dislodgment. However, it remains unclear whether the mechanical properties of TNTs formed by these two mechanisms are the same. Here, we developed novel microoperation methods to investigate the mechanical properties of TNTs in HEK293 cells, in which the TNTs form from thin finger-like actin assembly-driven protrusions and C2C12 cells, in which the TNTs form through contact and cell dislodgment. We found that TNTs formed by the two mechanisms represent elastic elements with similar tensile strength. In both the HEK and C2C12 cells, the tensile strength of TNTs exhibited a distinct size dependence on their lengths and diameters. Disturbing the cytoskeleton or removing extracellular Ca also changed their tensile strength. In addition, the stiffening of the extracellular matrix (ECM) enhanced the length, diameter and tensile strength of TNTs both in both HEK and C2C12 cells. Finally, a theoretical model was established to reveal the changes in the TNT's mechanical properties with its length, diameter and individual tunneling nanotubes (iTNT) number. This work not only gains insights into the properties of TNTs but also helps understand the dynamics of various cells.
连接细胞的隧道纳米管（TNTs）已被公认为是多种物质进行长距离细胞间运输的途径，这些物质包括病毒、溶酶体或其他细胞器、钙离子以及电信号。TNTs最初可由细指状肌动蛋白组装驱动的突起或细胞接触与脱离形成。然而，尚不清楚通过这两种机制形成的TNTs的力学性质是否相同。在此，我们开发了新的显微操作方法，以研究人胚肾293细胞（其中TNTs由细指状肌动蛋白组装驱动的突起形成）和C2C12细胞（其中TNTs通过接触和细胞脱离形成）中TNTs的力学性质。我们发现，由这两种机制形成的TNTs均为具有相似拉伸强度的弹性元件。在人胚肾细胞和C2C12细胞中，TNTs的拉伸强度均对其长度和直径呈现出明显的尺寸依赖性。扰乱细胞骨架或去除细胞外钙离子也会改变它们的拉伸强度。此外，细胞外基质（ECM）的硬化增强了人胚肾细胞和C2C12细胞中TNTs的长度、直径和拉伸强度。最后，建立了一个理论模型，以揭示TNTs力学性质随其长度、直径和单个隧道纳米管（iTNT）数量的变化。这项工作不仅深入了解了TNTs的性质，也有助于理解各种细胞的动态变化。
