Ca(2+) fluxes involvement in gene expression during cardiac hypertrophy

Area of Science:

• Cardiovascular Biology
• Molecular Cardiology
• Cell Signaling

Background:

• Cardiac hypertrophy is a heart response to pathological stimuli, involving genetic reprogramming.
• Calcium (Ca2+) acts as a key signaling molecule in initiating this reprogramming.
• Excitation-transcription (ET) coupling describes Ca2+ regulation of cardiac growth via transcription factors.

Purpose of the Study:

• To review neurohormonal signaling pathways that activate cardiac excitation-transcription (ET) coupling.
• To elucidate the role of Ca2+-dependent enzymes like CaMKII and calcineurin in cardiac hypertrophy.
• To highlight the contribution of adrenergic and renin-angiotensin-aldosterone systems to cardiac growth.

Main Methods:

• Review of existing literature on cardiac hypertrophy and signaling pathways.
• Analysis of Ca2+ signaling mechanisms in cardiac growth.
• Focus on neurohormonal activators of ET coupling, including adrenergic and angiotensin receptors.

Main Results:

• Ca2+ influx and intracellular Ca2+ levels regulate cardiac growth through Ca2+-dependent enzymes.
• Adrenergic stimulation (β-AR, α1 AR) and angiotensin II activate pathways leading to hypertrophy.
• IP3 and DAG signaling mediate Ca2+ release and entry, activating CaMKII/MEF2 and calcineurin/NFAT pathways.

Conclusions:

• Neurohormonal pathways are critical activators of cardiac ET coupling.
• Ca2+ signaling, mediated by CaMKII and calcineurin, is central to hypertrophy.
• Understanding these pathways offers targets for managing cardiac hypertrophy.