Non-Cell-Autonomous Cardiomyocyte Regulation Complicates Gene Supplementation Therapy for Lmna-Associated Cardiac...

Area of Science:

• Cardiovascular Biology
• Molecular Genetics
• Gene Therapy

Background:

• Truncating mutations in the Lamin A/C gene (LMNA) are a primary genetic cause of dilated cardiomyopathy and related cardiac disorders.
• LMNA mutations lead to cytoskeletal instability and cellular dysfunction, impacting cardiac structure and function.

Purpose of the Study:

• To investigate the role of LMNA in cardiac development and function using distinct mouse models of truncating LMNA mutations.
• To determine the cell-autonomous versus non-cell-autonomous effects of LMNA mutations on the heart.
• To evaluate the therapeutic potential of adeno-associated virus (AAV) mediated lamin-A addback strategies.

Main Methods:

• Generation and analysis of three mouse models with germline, cardiomyocyte-specific, or genetic mosaic truncating LMNA mutations.
• Administration of three types of adeno-associated virus (AAV) vectors for lamin-A addback: ubiquitous, cardiomyocyte-specific, and cardiomyocyte-excluded.
• Assessment of cardiac morphology, maturation, and function in response to genetic manipulation and gene therapy.

Main Results:

• Germline LMNA mutation caused cardiac maturation defects, while cardiomyocyte-specific mutation induced pathological hypertrophy.
• Genetic mosaic LMNA mutation did not result in observable morphological defects.
• Only ubiquitous and cardiomyocyte-excluded AAV vectors effectively mitigated cardiac defects, indicating a non-cell-autonomous mechanism.

Conclusions:

• LMNA regulates cardiac morphology and function through a non-cell-autonomous mechanism, impacting non-cardiomyocyte populations.
• Non-cardiomyocytes are critical therapeutic targets for AAV-mediated gene therapy aimed at treating LMNA-associated cardiac defects.