DNA hydroxymethylation controls cardiomyocyte gene expression in development and hypertrophy

Area of Science:

• Epigenetics
• Cardiovascular Biology
• Molecular Cardiology

Background:

• 5-methylcytosine (5-mC) is a key epigenetic DNA modification linked to cardiac disease.
• The role of 5-hydroxymethylcytosine (5-hmC), an oxidation product of 5-mC, in cardiac biology and disease remains largely unknown.

Purpose of the Study:

• To investigate the role and genome-wide distribution of 5-hmC in cardiomyocytes during cardiac development and in pathological hypertrophy.
• To understand the association between 5-hmC dynamics and transcriptional networks in the heart.

Main Methods:

• Genome-wide analysis of the hydroxymethylome in mouse cardiomyocytes across different developmental stages (embryonic, neonatal, adult) and in a model of cardiac hypertrophy.
• Correlation analysis between 5-hmC marks and gene expression patterns.
• Investigation of the ten-eleven translocation 2 (TET2) enzyme's role in regulating cardiac gene expression via 5-hmC.

Main Results:

• Dynamic modulation of DNA hydroxymethylation (5-hmC) is associated with specific transcriptional networks during heart development and failure.
• 5-hmC marks are enriched in the gene bodies of highly expressed genes and active distal regulatory regions.
• Pathological cardiac hypertrophy exhibits a shift in 5-hmC distribution patterns, resembling a neonatal profile.
• The TET2 enzyme regulates key cardiac genes, including Myh7, through 5-hmC deposition in gene bodies and enhancers.

Conclusions:

• This study provides the first genome-wide analysis of 5-hmC in cardiomyocytes.
• 5-hmC is dynamically regulated during heart development and disease, suggesting a significant role for this epigenetic modification in cardiac biology.
• The findings highlight 5-hmC as a potential regulator of cardiac gene expression and a biomarker for cardiac pathologies.