NLRP3 Inflammasome Activation Through Heart-Brain Interaction Initiates Cardiac Inflammation and Hypertrophy During...

Area of Science:

• Cardiovascular Biology
• Neuroimmunology
• Molecular Cardiology

Background:

• Mechanical stress on the heart, like high blood pressure, triggers inflammation and cardiac hypertrophy.
• The precise mechanisms regulating inflammation in stressed hearts are not fully understood.
• Interleukin-1β (IL-1β) is a key proinflammatory cytokine implicated in cardiac hypertrophy and heart failure.

Purpose of the Study:

• To investigate the role of neural signals in activating the NLRP3 inflammasome and IL-1β production in the stressed heart.
• To elucidate the regulatory mechanisms of inflammation and cardiac hypertrophy under mechanical stress.
• To explore the therapeutic potential of targeting neural pathways in hypertensive heart disease.

Main Methods:

• Utilized various mouse models, including NLRP3 and P2RX7 knockouts, and adrenergic neuron-specific knockouts.
• Induced pressure overload via transverse aortic constriction and employed pharmacological interventions.
• Assessed cardiac function, morphology, gene expression, inflammasome activity, and extracellular ATP levels.
• Conducted in vitro experiments on primary cardiomyocytes, fibroblasts, and endothelial cells.

Main Results:

• Genetic deletion of NLRP3 significantly reduced IL-1β production, cardiac hypertrophy, and contractile dysfunction.
• The ATP/P2X7 axis was crucial for NLRP3 inflammasome activation, cardiac inflammation, and hypertrophy.
• Sympathetic efferent nerves were identified as a major source of extracellular ATP, mediating hypertrophic responses.
• Targeting neural signals, such as reducing sympathetic efferent nerve activity, inhibited NLRP3 inflammasome activation and adaptive cardiac hypertrophy.

Conclusions:

• Cardiac inflammation and hypertrophy are intricately regulated by heart-brain interactions.
• Neural signals play a critical role in initiating adaptive cardiac hypertrophy via the NLRP3 inflammasome pathway.
• Modulating neural signals presents a potential therapeutic strategy for managing hypertensive heart disease.