LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.
PLoS One. 2013 Jul 3;8(7):e67708. doi: 10.1371/journal.pone.0067708. Print 2013.
Recent studies indicate that the cell membrane, interacting with its attached cytoskeleton, is an important regulator of cell function, exerting and responding to forces. We investigate this relationship by looking for connections between cell membrane elastic properties, especially surface tension and bending modulus, and cell function. Those properties are measured by pulling tethers from the cell membrane with optical tweezers. Their values are determined for all major cell types of the central nervous system, as well as for macrophage. Astrocytes and glioblastoma cells, which are considerably more dynamic than neurons, have substantially larger surface tensions. Resting microglia, which continually scan their environment through motility and protrusions, have the highest elastic constants, with values similar to those for resting macrophage. For both microglia and macrophage, we find a sharp softening of bending modulus between their resting and activated forms, which is very advantageous for their acquisition of phagocytic functions upon activation. We also determine the elastic constants of pure cell membrane, with no attached cytoskeleton. For all cell types, the presence of F-actin within tethers, contrary to conventional wisdom, is confirmed. Our findings suggest the existence of a close connection between membrane elastic constants and cell function.
最近的研究表明，细胞膜与其附着的细胞骨架相互作用，是细胞功能的重要调节者，能够施加和响应力。我们通过寻找细胞膜弹性特性（特别是表面张力和弯曲模量）与细胞功能之间的联系来研究这种关系。这些特性是通过用光学镊子从细胞膜上拉动系绳来测量的。我们测量了中枢神经系统的所有主要细胞类型以及巨噬细胞的这些特性。与神经元相比，具有较大动态性的星形胶质细胞和神经胶质瘤细胞具有较大的表面张力。静止的小神经胶质细胞通过运动和突起不断扫描其环境，具有最高的弹性常数，其值与静止的巨噬细胞相似。对于小神经胶质细胞和巨噬细胞，我们发现它们的弯曲模量在静止和激活两种状态之间明显变软，这对于它们在激活后获得吞噬功能非常有利。我们还确定了没有附着细胞骨架的纯细胞膜的弹性常数。对于所有细胞类型，都证实了在系绳内存在 F-肌动蛋白，这与传统观点相反。我们的发现表明，膜弹性常数与细胞功能之间存在密切联系。
