TrpC3 regulates hypertrophy-associated gene expression without affecting myocyte beating or cell size.

Area of Science:

• Cardiovascular Biology
• Molecular Cardiology
• Ion Channel Physiology

Background:

• Pathological cardiac hypertrophy increases heart failure risk and mortality.
• Calcium (Ca2+) signaling is crucial for hypertrophy, but distinct Ca2+ signals for contraction versus gene expression remain unclear.
• Understanding the molecular basis of Ca2+-dependent hypertrophic gene expression is vital.

Purpose of the Study:

• To identify ion channels mediating Ca2+-dependent gene expression in cardiac hypertrophy.
• To investigate the role of Transient Receptor Potential C3 (TrpC3) in pathological cardiac hypertrophy.
• To differentiate TrpC3's role in hypertrophic gene expression from its role in myocyte contraction and size.

Main Methods:

• In vitro neonatal rat ventricular myocytes were used for an RNA interference (RNAi) screen.
• RNAi was employed to knock down TrpC3 expression and assess its impact on hypertrophic gene markers.
• TrpC3 overexpression studies were conducted to confirm its role in gene expression.

Main Results:

• Transient Receptor Potential C3 (TrpC3) was identified as a key ion channel involved in hypertrophic gene expression.
• TrpC3 knockdown significantly reduced expression of hypertrophy-associated genes like natriuretic peptides (ANP, BNP).
• TrpC3 knockdown did not significantly affect myocyte cell size or beating, suggesting a specific role in gene transcription.

Conclusions:

• Ca2+ influx through TrpC3 channels selectively enhances the transcription of hypertrophy-associated genes.
• TrpC3 plays a critical role in mediating hypertrophic gene expression distinct from regulating cell size or contraction.
• TrpC3 represents a potential therapeutic target for treating cardiac hypertrophy and preventing heart failure.