Drp1 regulates transcription of ribosomal protein genes in embryonic hearts

Area of Science:

• Developmental Biology
• Mitochondrial Biology
• Cardiovascular Research

Background:

• Mitochondrial dysfunction is linked to congenital heart defects and lethality.
• Understanding mitochondrial roles in cardiogenesis is crucial for treating cardiomyopathies.
• Mitochondrial morphology, regulated by fission and fusion, impacts cellular activity.

Purpose of the Study:

• To investigate the role of dynamin-related protein 1 (Drp1) in heart development.
• To elucidate the impact of Drp1-mediated mitochondrial fission on cardiogenesis.
• To understand the molecular mechanisms linking mitochondrial dysfunction to cardiac defects.

Main Methods:

• Specific inactivation of Dnm1l (encoding Drp1) in second heart field-derived cells in mice.
• Analysis of mitochondrial morphology, ultrastructure, and activity in mutant cardiomyocytes.
• Characterization of molecular pathways, including the AMPK-SIRT7-GABPB axis.

Main Results:

• Inactivation of Dnm1l led to severe mitochondrial defects in right ventricle (RV) cardiomyocytes.
• Mutant cardiomyocytes exhibited increased cell death, reduced survival, and disorganized structure.
• A novel AMPK-SIRT7-GABPB axis was identified, linking energy levels to ribosomal gene transcription.

Conclusions:

• Drp1 is essential for proper RV development in mice.
• Mitochondrial dysfunction, caused by impaired fission, leads to cardiac abnormalities and embryonic lethality.
• This study provides mechanistic insights into mitochondrial dysfunction-induced cardiomyopathies.