Endophilin B1 is essential for maintaining cardiac function by regulating mitocytosis

Area of Science:

• Cardiovascular Biology
• Mitochondrial Dynamics
• Cellular Stress Response

Background:

• Endophilin B1, a member of the Endophilin family, is implicated in apoptosis, mitochondrial morphology, and autophagy.
• While highly expressed in the heart, Endophilin B1's specific roles in cardiac function and ischemia-reperfusion (I/R) injury are not well understood.

Purpose of the Study:

• To investigate the role of Endophilin B1 in maintaining normal cardiac function.
• To determine the impact of Endophilin B1 on myocardial ischemia and reperfusion (I/R) injury.

Main Methods:

• Utilized Endophilin B1 deletion mouse models at different ages (8 and 16 weeks).
• Assessed cardiac function, hypertrophy, fibrosis, and cardiomyocyte death.
• Investigated mitochondrial structure, function, and localization using microscopy and biochemical assays.
• Examined the process of mitocytosis and extracellular vesicle involvement.

Main Results:

• Endophilin B1 deletion led to spontaneous cardiac dysfunction, hypertrophy, and fibrosis in aged mice.
• Deletion exacerbated I/R-induced cardiac dysfunction and cardiomyocyte death, while restoration ameliorated injury.
• Endophilin B1 is crucial for mitochondrial integrity and function, and its absence impairs mitocytosis via extracellular vesicles.

Conclusions:

• Endophilin B1 is essential for maintaining mitochondrial homeostasis and normal cardiac function.
• Endophilin B1 regulates mitocytosis, a key process for clearing damaged mitochondria.
• Endophilin B1 represents a novel therapeutic target for cardiac disorders, including I/R injury, myocardial infarction, and heart failure.