Imbalanced OPA1 processing and mitochondrial fragmentation cause heart failure in mice

Area of Science:

• Mitochondrial biology
• Cardiovascular research
• Molecular cell biology

Background:

• Mitochondrial morphology is regulated by fusion and fission processes.
• The dynamin-like protein OPA1 plays a key role in mitochondrial fusion.
• Processing of OPA1 by peptidases YME1L and OMA1 is essential for its function.

Purpose of the Study:

• To investigate the role of OPA1 processing by YME1L and OMA1 in adult myocardial function.
• To determine the impact of altered mitochondrial morphology on cardiac metabolism and heart failure.

Main Methods:

• Cardiac-specific ablation of Yme1l in mice.
• Genetic deletion of Oma1 in mice.
• Analysis of mitochondrial morphology, OPA1 processing, cardiac metabolism, and heart function.
• High-fat diet intervention.

Main Results:

• Cardiac-specific Yme1l ablation led to OMA1 activation, accelerated OPA1 proteolysis, mitochondrial fragmentation, altered cardiac metabolism, dilated cardiomyopathy, and heart failure.
• Oma1 deletion rescued cardiac function and mitochondrial morphology by preventing OPA1 cleavage.
• High-fat diet or skeletal muscle Yme1l ablation restored cardiac metabolism and function without preventing mitochondrial fragmentation.

Conclusions:

• Unprocessed OPA1 is sufficient for maintaining heart function.
• OMA1 is a critical regulator of cardiomyocyte survival.
• Mitochondrial morphology and cardiac metabolism are intrinsically linked in maintaining heart health.