Theragnosis Research Center, Biomedical Research Division, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea.
Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02792, Republic of Korea.
J Phys Chem B. 2021 Sep 16;125(36):10182-10194. doi: 10.1021/acs.jpcb.1c05403. Epub 2021 Sep 2.
Cellular senescence is the irreversible cell cycle arrest in response to various types of stress. Although the plasma membrane and its composition are significantly affected by cellular senescence, detailed studies on the physical properties of the plasma membrane have shown inconclusive results. In this study, we utilized both ensemble and single-molecule fluorescence imaging to investigate how membrane properties, such as fluidity, hydrophobicity, and ganglioside GM1 level are affected by cellular senescence. The diffusion coefficient of lipid probes, as well as the type of diffusion determined by an exponent α, which is the slope of the log-log plot of mean squared displacement as a function of time lag, were analyzed. We found that the number of molecules with a lower diffusion coefficient increased as cells became senescent. The changes in the population with a lower diffusion coefficient, observed after methyl-β-cyclodextrin treatment, and the increase in ceramide levels, detected using a ceramide-specific antibody, suggest that ceramide-rich lipid rafts were enhanced in senescent cells. Our results emphasize the importance of membrane properties in cellular senescence and might serve as a base for in-depth studies to determine how such domains facilitate the signaling pathway specific to cellular senescence.
细胞衰老（Cellular senescence）是细胞对各种类型的应激而产生的不可逆的细胞周期停滞。尽管质膜及其组成受到细胞衰老的显著影响，但对质膜物理性质的详细研究结果并不一致。在这项研究中，我们利用集体和单分子荧光成像来研究细胞膜性质（如流动性、疏水性和神经节苷脂 GM1 水平）如何受到细胞衰老的影响。我们分析了脂质探针的扩散系数以及扩散的类型，通过扩散指数 α 来确定，它是均方位移随时间滞后的对数-对数图的斜率。我们发现，随着细胞衰老，具有较低扩散系数的分子数量增加。用甲基-β-环糊精处理后观察到具有较低扩散系数的群体的变化，以及使用神经节苷脂特异性抗体检测到的神经节苷脂水平的增加，表明衰老细胞中富含神经节苷脂的脂筏增强。我们的研究结果强调了膜性质在细胞衰老中的重要性，并可能为深入研究确定这些结构域如何促进细胞衰老特有的信号通路提供基础。
