Altered mitochondrial epigenetics associated with subchronic doxorubicin cardiotoxicity

Area of Science:

• Cardiology
• Molecular Biology
• Pharmacology

Background:

• Doxorubicin (DOX) is a chemotherapy drug known to cause dose-dependent cardiotoxicity, leading to heart failure.
• The exact mechanisms of DOX-induced cardiotoxicity are not fully understood but involve mitochondrial dysfunction.
• Epigenetic modifications may play a role in the cardiac effects of DOX.

Purpose of the Study:

• To investigate the hypothesis that DOX cardiotoxicity results from epigenetic changes linked to mitochondrial dysfunction.
• To explore the impact of DOX on DNA methylation, gene expression, and protein acetylation in cardiac tissue.

Main Methods:

• Male Wistar rats received weekly DOX injections or saline control.
• Cardiac tissue was analyzed for gene expression (qPCR), global DNA methylation (ELISA), and protein acetylation (Western blot).
• Mitochondrial DNA levels and histone deacetylase activity were also assessed.

Main Results:

• DOX treatment significantly decreased global DNA methylation in rat hearts, but not in the liver.
• DOX disrupted cardiac mitochondrial biogenesis, evidenced by reduced mtDNA and altered mitochondrial gene expression.
• Changes in mRNA expression of lipid metabolism and epigenetic genes, alongside altered protein acetylation and increased histone deacetylase activity, were observed.

Conclusions:

• DOX-induced cardiotoxicity involves a complex interplay between mitochondrial dysfunction and epigenetic alterations.
• Decreased DNA methylation and disrupted mitochondrial function are suggested as primary drivers of DOX cardiotoxicity.
• These findings offer new insights into the mechanisms of chemotherapy-induced heart damage.