Mitochondrial protein OPA3 sustains cardiac function by regulating calcium handling in male mice

Area of Science:

• Cardiology
• Mitochondrial Biology
• Molecular Mechanisms of Heart Failure

Background:

• Heart failure (HF) is a major global health challenge.
• Impaired cardiac contractility, remodeling, calcium (Ca2+) handling, and mitochondrial dysfunction characterize HF.
• The molecular regulators of these processes are not fully understood.

Purpose of the Study:

• To investigate the role of Opa3 in heart failure.
• To elucidate the molecular mechanisms by which Opa3 influences cardiac function.

Main Methods:

• Studied OPA3 levels in human and murine HF.
• Generated cardiomyocyte-specific Opa3 knockout mice.
• Assessed cardiac function, Ca2+ handling, and mitochondrial function.
• Investigated OPA3 interactions with phospholamban (PLN) and SERCA2a.
• Utilized pressure overload and doxorubicin HF models in mice.

Main Results:

• OPA3 levels were reduced in human and murine HF.
• Cardiomyocyte-specific Opa3 deletion induced dilated cardiomyopathy (DCM) with impaired cardiac function, Ca2+ cycling, and mitochondrial function.
• OPA3 is crucial for PLN interaction, maintaining SERCA2a activity and Ca2+ handling.
• OPA3 deficiency impairs mitochondrial outer membrane function.
• Opa3 overexpression ameliorated cardiac dysfunction in HF models.

Conclusions:

• OPA3 plays a critical role in maintaining cardiac function.
• The OPA3-PLN-SERCA2a axis regulates both mitochondrial and sarcoplasmic reticulum function.
• OPA3 represents a potential therapeutic target for heart failure.