Fibroblasts modulate cardiomyocyte excitability: implications for cardiac gene therapy

Area of Science:

• Cardiovascular Biology
• Cellular Electrophysiology
• Biomedical Engineering

Background:

• Myotubes engineered for gene therapy can exhibit reduced excitability.
• This phenomenon may involve interactions with supporting fibroblast cells.
• Connexin43 (Cx43) is a key protein in cell-to-cell communication.

Purpose of the Study:

• To investigate the role of fibroblast connexin43 (Cx43) in modulating cardiomyocyte excitability.
• To determine if Cx43-mediated heterologous coupling impacts cardiac function.
• To inform gene transfer strategies for myocardial repair.

Main Methods:

• Co-culture of neonatal rat cardiomyocytes with mouse fibroblasts.
• Manipulation of Cx43 expression in fibroblasts (wild-type, knockout, dominant-negative).
• Measurement of cardiomyocyte intrinsic beat frequency.

Main Results:

• Cardiomyocytes on wild-type fibroblasts beat significantly slower than those on Cx43-deficient fibroblasts.
• Suppression of Cx43 function in fibroblasts reduced cardiomyocyte excitability.
• Restoring Cx43 expression in knockout fibroblasts normalized cardiomyocyte beat frequency.

Conclusions:

• Fibroblasts modulate cardiomyocyte excitability in a connexin43 (Cx43)-dependent manner.
• Cx43-mediated heterologous coupling can significantly impact cardiac electrical activity.
• Understanding this interaction is vital for developing effective gene therapies for heart conditions.