Cardiac fibroblasts counterbalance cardiomyocytes in LMNA cardiomyopathy pathogenesis

Area of Science:

• Cardiovascular Biology
• Cellular Biology
• Genetics

Background:

• Mutations in the LMNA gene lead to genetic cardiomyopathies with unpredictable severity and fibrosis.
• The role of lamin A/C in cardiac fibroblast function, crucial for fibrosis, remains largely unknown.
• Understanding cellular mechanisms driving disease variability is essential for effective treatment.

Purpose of the Study:

• To investigate the function of lamin A/C in cardiac fibroblasts.
• To determine how LMNA mutations affect cardiac fibroblast behavior in response to myocyte damage.
• To elucidate the role of lamin A/C in mediating interactions between cardiomyocytes and cardiac fibroblasts in disease pathogenesis.

Main Methods:

• Primary cardiac fibroblast culture and manipulation of lamin A/C expression (depletion and point mutants).
• Assessment of cardiac fibroblast proliferation, contraction, and migration.
• In vivo studies using mouse models with simultaneous lamin A/C depletion in cardiomyocytes and cardiac fibroblasts.
• Evaluation of cardiac function, disease progression, and survival in mouse models.

Main Results:

• Lamin A/C depletion and mutant expression impaired cardiac fibroblast proliferation and contraction.
• Cell migration was affected in a mutation-dependent manner.
• Simultaneous in vivo depletion of lamin A/C in both cell types significantly delayed disease progression, improved cardiac function, and prolonged survival.
• Lamin A/C plays a critical role in balancing cardiomyocyte and cardiac fibroblast contributions to disease.

Conclusions:

• Lamin A/C has previously unrecognized functions in cardiac fibroblasts.
• LMNA mutations impact cardiac fibroblast behavior, influencing cardiomyopathy progression.
• Targeting lamin A/C in both cardiomyocytes and cardiac fibroblasts may offer a therapeutic strategy for LMNA cardiomyopathy by modulating cell-cell interactions.