Ren Wei, Ge Xichuan, Li Meiqi, Sun Jing, Li Shiyi, Gao Shu, Shan Chunyan, Gao Baoxiang, Xi Peng
Department of Biomedical Engineering, National Biomedical Imaging Center, College of Future Technology, Peking University, Beijing, 100871, China.
Key Laboratory of Analytical Science and Technology of Hebei Province, College of Chemistry and Material Science, Hebei University, Baoding, 071002, China.
Light Sci Appl. 2024 May 24;13(1):116. doi: 10.1038/s41377-024-01463-9.
Mitochondria are crucial organelles closely associated with cellular metabolism and function. Mitochondrial DNA (mtDNA) encodes a variety of transcripts and proteins essential for cellular function. However, the interaction between the inner membrane (IM) and mtDNA remains elusive due to the limitations in spatiotemporal resolution offered by conventional microscopy and the absence of suitable in vivo probes specifically targeting the IM. Here, we have developed a novel fluorescence probe called HBmito Crimson, characterized by exceptional photostability, fluorogenicity within lipid membranes, and low saturation power. We successfully achieved over 500 frames of low-power stimulated emission depletion microscopy (STED) imaging to visualize the IM dynamics, with a spatial resolution of 40 nm. By utilizing dual-color imaging of the IM and mtDNA, it has been uncovered that mtDNA tends to habitat at mitochondrial tips or branch points, exhibiting an overall spatially uniform distribution. Notably, the dynamics of mitochondria are intricately associated with the positioning of mtDNA, and fusion consistently occurs in close proximity to mtDNA to minimize pressure during cristae remodeling. In healthy cells, >66% of the mitochondria are Class III (i.e., mitochondria >5 μm or with >12 cristae), while it dropped to <18% in ferroptosis. Mitochondrial dynamics, orchestrated by cristae remodeling, foster the even distribution of mtDNA. Conversely, in conditions of apoptosis and ferroptosis where the cristae structure is compromised, mtDNA distribution becomes irregular. These findings, achieved with unprecedented spatiotemporal resolution, reveal the intricate interplay between cristae and mtDNA and provide insights into the driving forces behind mtDNA distribution.
线粒体是与细胞代谢和功能密切相关的关键细胞器。线粒体DNA(mtDNA)编码多种对细胞功能至关重要的转录本和蛋白质。然而,由于传统显微镜在时空分辨率上的局限性以及缺乏专门针对内膜(IM)的合适体内探针,内膜与mtDNA之间的相互作用仍不清楚。在此,我们开发了一种名为HBmito Crimson的新型荧光探针,其特点是具有出色的光稳定性、在脂质膜内的荧光生成能力以及低饱和功率。我们成功实现了超过500帧的低功率受激发射损耗显微镜(STED)成像,以可视化内膜动态,空间分辨率为40纳米。通过对内膜和mtDNA进行双色成像,发现mtDNA倾向于栖息在线粒体的尖端或分支点,呈现出整体空间均匀分布。值得注意的是,线粒体的动态与mtDNA的定位密切相关,并且融合始终在靠近mtDNA的位置发生,以在嵴重塑过程中最小化压力。在健康细胞中,>66%的线粒体属于III类(即线粒体>5微米或有>12个嵴),而在铁死亡中这一比例降至<18%。由嵴重塑协调的线粒体动态促进了mtDNA的均匀分布。相反,在凋亡和铁死亡条件下,嵴结构受损,mtDNA分布变得不规则。这些以前所未有的时空分辨率获得的发现,揭示了嵴与mtDNA之间复杂的相互作用,并为mtDNA分布背后的驱动力提供了见解。