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Updated: Dec 12, 2025
A Flow Cytometry-based Assay for Measuring Mitochondrial Membrane Potential in Cardiac Myocytes After Hypoxia/Reoxygenation
Published on: July 13, 2018
Inner mitochondrial membrane protein MPV17 mutant mice display increased myocardial injury after ischemia/reperfusion
Ngonidzashe B Madungwe1,2, Yansheng Feng1, Abdulhafiz Imam Aliagan1
1Department of Cellular and Integrative Physiology, School of Medicine, University of Texas Health Science Center at San Antonio TX 78229, USA.
Abstract:
MPV17 is an inner mitochondrial membrane protein whose mutation results in mitochondrial DNA (mtDNA) depletion diseases such as neurohepatopathy. MPV17 is expressed in several organs including the liver and kidneys. Here, we investigated its role and mechanism of action in cardiac ischemia/reperfusion (I/R) injury. Using isolated hearts from wild type and Mpv17 mutant (Mpv17mut) mice, we found that mtDNA levels and normal cardiac function were similar between the groups. Furthermore, reactive oxygen species (ROS) generation, mitochondrial morphology, and calcium levels required to trigger mitochondrial permeability transition pore (mPTP) opening were all similar in normal/non-ischemic animals. However, following I/R, we found that mutant mice had poorer cardiac functional recovery and exhibited more mitochondrial structural damage. We also found that after I/R, Mpv17mut heart mitochondria did not produce more ROS than wild type hearts but that calcium retention capacity was gravely compromised. Using immunoprecipitation and mass spectrometry, we identified ATP synthase, Cyclophilin D, MIC60 and GRP75 as proteins critical to mitochondrial cristae organization and calcium handling that interact with MPV17, and this interaction is reduced by I/R. Together our results suggest that MPV17 has a protective function in the heart and is necessary for recovery following insults to the heart.
Insights
MPV17 protein protects the heart from damage during ischemia/reperfusion injury. Mutations impair cardiac recovery and mitochondrial function after heart insults.
Area of Science:
- Mitochondrial biology
- Cardiovascular research
- Cellular stress response
Background:
- MPV17 is an inner mitochondrial membrane protein linked to mtDNA depletion diseases.
- Its role in cardiac ischemia/reperfusion (I/R) injury is not well understood.
Purpose of the Study:
- To investigate the function and mechanism of MPV17 in cardiac I/R injury.
- To determine if MPV17 deficiency compromises heart function and mitochondrial integrity post-insult.
Main Methods:
- Comparison of cardiac function and mitochondrial parameters between wild type and Mpv17 mutant mice under normal and I/R conditions.
- Assessment of reactive oxygen species (ROS) generation, mitochondrial morphology, and calcium handling.
- Identification of interacting proteins using immunoprecipitation and mass spectrometry.
Main Results:
- Mpv17 mutant hearts showed poorer functional recovery and increased mitochondrial damage after I/R compared to wild type.
- Mutant mitochondria exhibited compromised calcium retention capacity post-I/R, but not increased ROS production.
- MPV17 interacts with ATP synthase, Cyclophilin D, MIC60, and GRP75, crucial for mitochondrial structure and calcium handling; this interaction decreases after I/R.
Conclusions:
- MPV17 plays a protective role in the heart.
- MPV17 is essential for cardiac recovery following I/R injury.
- MPV17's interaction with key mitochondrial proteins is vital for maintaining cardiac function under stress.
