Fang Jingde, Zhang Hao, Smith Zachary J, Chu Kaiqin
Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230027, China.
Suzhou Institute for Advanced Research, University of Science and Technology of China, Suzhou, Jiangsu 215123, China.
Biomed Opt Express. 2025 Mar 26;16(4):1602-1615. doi: 10.1364/BOE.557745. eCollection 2025 Apr 1.
Mitochondria plays an important role in cell death and undergoes dramatic changes in states of disequilibrium. As mitochondria respond sensitively to cell stress, their dynamics should be studied without affecting cell state. However, current methods rely on labeling cells with fluorescence and introduce additional stress to the cell due to photobleaching and phototoxicity. Here, we propose to use label-free organelle-specific phase contrast microscopy (OS-PCM) to achieve prolonged, specific observation and quantitative analysis of mitochondria dynamics during cell death with minimum perturbation to cells. Using apoptosis and ferroptosis as two examples of cell death, we show quantitatively that large mitochondria tend to increase in size through a combination of swelling and fusion in response to apoptosis, while they decrease in size through fission during ferroptosis. These results provide a new and deeper understanding of mitochondrial dynamics during cell death and demonstrate that OS-PCM is a powerful tool for the gentle, facile, and quantitative study of delicate organelles under stress.
线粒体在细胞死亡中起重要作用，并且在失衡状态下会发生显著变化。由于线粒体对细胞应激反应敏感，因此在不影响细胞状态的情况下研究其动态变化至关重要。然而，目前的方法依赖于用荧光标记细胞，并且由于光漂白和光毒性会给细胞带来额外的应激。在此，我们建议使用无标记的细胞器特异性相差显微镜（OS-PCM），以在对细胞造成最小扰动的情况下，对细胞死亡过程中的线粒体动态变化进行长时间、特异性的观察和定量分析。以细胞凋亡和铁死亡这两种细胞死亡为例，我们定量显示，大的线粒体在细胞凋亡时倾向于通过肿胀和融合的组合而增大尺寸，而在铁死亡期间则通过裂变减小尺寸。这些结果为细胞死亡过程中的线粒体动态变化提供了新的、更深入的理解，并证明OS-PCM是一种用于在应激条件下对精细细胞器进行温和、简便和定量研究的强大工具。
