Cardiomyocyte Homeodomain-Interacting Protein Kinase 2 Maintains Basal Cardiac Function via Extracellular...

Area of Science:

• Cardiovascular Biology
• Molecular Cardiology
• Biochemistry

Background:

• Cardiac kinases are crucial in heart failure development and represent therapeutic targets.
• The cardiac kinome remains largely unexplored, necessitating the identification of novel kinases.
• Homeodomain-Interacting Protein Kinase 2 (HIPK2) was identified as a novel candidate kinase involved in cardiac function.

Purpose of the Study:

• To investigate the role of HIPK2 in cardiac biology and its potential involvement in heart failure.
• To elucidate the molecular mechanisms underlying HIPK2's function in cardiomyocytes.
• To assess the therapeutic potential of targeting HIPK2 in cardiovascular disease.

Main Methods:

• Utilized transcriptomics and bioinformatics for kinase target screening (Expression2Kinase algorithm).
• Generated cardiomyocyte-specific HIPK2 knockout and heterozygous mouse models.
• Assessed cardiac function via echocardiography and molecular analyses; employed AAV-mediated gene delivery for rescue experiments.

Main Results:

• Loss of HIPK2 in cardiomyocytes leads to age-dependent cardiac dysfunction, indicating a causal role in heart failure.
• A gene dose-response relationship was observed between HIPK2 levels and cardiac function.
• Reduced HIPK2 expression in human end-stage ischemic cardiomyopathy suggests clinical relevance.
• HIPK2 deficiency impairs extracellular signal-regulated kinase 1/2 (ERK1/2) signaling, leading to apoptosis and cardiac dysfunction.
• Rescue experiments targeting MEK1-CA partially restored cardiac function in HIPK2-deficient mice.

Conclusions:

• Cardiomyocyte HIPK2 is essential for maintaining normal cardiac function.
• HIPK2 regulates cardiac function through the extracellular signal-regulated kinase (ERK) signaling pathway.
• HIPK2 represents a potential therapeutic target for heart failure.