Rapamycin Alleviates Heart Failure Caused by Mitochondrial Dysfunction and SERCA Hypoactivity in Syntaxin 12/13...

Area of Science:

• Cardiovascular Biology
• Mitochondrial Physiology
• Cellular Metabolism

Background:

• Syntaxin 12/13 (STX12) is a protein family member found in the brain and heart, crucial for vesicle recycling.
• The specific role of STX12 in cardiovascular physiology is not well understood.

Purpose of the Study:

• To investigate the function of STX12 in cardiovascular health.
• To elucidate the molecular mechanisms underlying STX12 deficiency-induced cardiac dysfunction.
• To explore potential therapeutic interventions for STX12-related cardiomyopathies.

Main Methods:

• Utilized zebrafish and mouse models to study STX12 loss-of-function.
• Analyzed cardiac morphology, mitochondrial function, and cellular calcium handling.
• Investigated the effects of rapamycin treatment on STX12-deficient models.

Main Results:

• STX12 loss resulted in pericardial edema, cardiac malformations, and heart failure.
• Depletion of STX12 impaired mitochondrial morphology, reduced iron and zinc levels, and decreased ATP production.
• STX12-deficient cardiomyocytes showed prolonged repolarization due to reduced sarcoplasmic reticulum Ca2+-ATPase (SERCA) activity.
• Rapamycin treatment improved mitochondrial function, enhanced SERCA activity, and reduced stress markers.

Conclusions:

• STX12 is vital for cardiomyocyte energy metabolism and metal homeostasis.
• Rapamycin shows promise in treating cardiomyopathies by enhancing mitochondrial function, autophagy, and SERCA activity via specific molecular pathways (TFEB-PGC1α and CAMKII-phospholamban).