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Updated: May 3, 2026
In Vitro and In Vivo Detection of Mitophagy in Human Cells, C. Elegans, and Mice
Published on: November 22, 2017
Dual-Modality Imaging Unveil Inner Mitochondrial Membrane Viscosity and Respiratory Dynamics in Mitophagy
Fei Peng1, Xiangnan Ai1, Bin Hao2
1College of Chemistry and Materials Science, Hebei University, Baoding 071002, China.
Abstract:
Mitophagy is a vital lysosome-dependent process that maintains mitochondrial integrity and cellular homeostasis, where respiration and inner mitochondrial membrane (IMM) viscosity play key roles. Despite its critical importance, achieving a high-resolution and dynamic visualization of respiration and IMM viscosity during mitophagy remains a significant challenge. In this study, we designed two innovative fluorescent probes: SiR-C8, a viscosity-sensitive rotor-type probe based on silicon-rhodamine, specifically targeting the IMM, and OR-ATP, a rhodamine-derived probe utilizing an intramolecular spirolactam structure to respond to mitochondrial ATP levels. Leveraging fluorescence intensity and lifetime dual-modality imaging, we successfully enabled the high-resolution, real-time monitoring of lysosome-dependent mitophagy. Remarkably, our results unveiled a progressive increase in IMM viscosity alongside a significant attenuation in mitochondrial respiration during mitophagy induced by starvation, carbonyl cyanide, m-chlorophenyl hydrazone (CCCP), and Oligomycin. Significantly, utilizing structured illumination microscopy super-resolution imaging, we have uncovered a novel mitochondrial quality control mechanism by which lysosomes selectively engulf locally damaged mitochondrial regions. This discovery provides novel insights into the intricate processes governing mitophagy and introduces an innovative platform for studying mitochondrial dynamics, dysfunction, and their implications for cellular homeostasis and pathology.
Insights
Researchers developed new fluorescent probes to visualize mitochondrial viscosity and respiration during mitophagy. This revealed lysosomes selectively engulf damaged mitochondrial regions, offering new insights into cellular quality control.
Area of Science:
- Cell Biology
- Mitochondrial Dynamics
- Lysosome Function
Background:
- Mitophagy is crucial for maintaining cellular homeostasis by removing damaged mitochondria.
- Visualizing mitochondrial respiration and inner mitochondrial membrane (IMM) viscosity during mitophagy is challenging.
- Existing methods lack the resolution and dynamic capabilities to study mitophagy in real-time.
Purpose of the Study:
- To develop novel fluorescent probes for high-resolution, real-time monitoring of mitophagy.
- To investigate changes in IMM viscosity and mitochondrial respiration during mitophagy.
- To uncover novel mechanisms of mitochondrial quality control.
Main Methods:
- Design and synthesis of two novel fluorescent probes: SiR-C8 (IMM viscosity) and OR-ATP (ATP levels).
- Utilized fluorescence intensity and lifetime dual-modality imaging for real-time mitophagy monitoring.
- Employed structured illumination microscopy super-resolution imaging to visualize mitochondrial-lysosome interactions.
Main Results:
- Successfully enabled high-resolution, real-time monitoring of lysosome-dependent mitophagy.
- Observed increased IMM viscosity and decreased mitochondrial respiration during mitophagy.
- Discovered a novel mechanism where lysosomes selectively engulf damaged mitochondrial regions.
Conclusions:
- The developed probes provide an innovative platform for studying mitophagy and mitochondrial dynamics.
- Mitophagy involves increased IMM viscosity and reduced respiration, coupled with selective lysosomal engulfment of damaged regions.
- This study offers new insights into mitochondrial quality control and cellular homeostasis.
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