Histone H2A.Z Deacetylation and Dedifferentiation in Infarcted/Tip60-depleted Cardiomyocytes

Area of Science:

• Cardiovascular Biology
• Molecular Cardiology
• Epigenetics

Background:

• Myocardial infarction (MI) causes significant cardiomyocyte (CM) loss, leading to cardiac dysfunction.
• Regenerating the heart requires CM proliferation, but current approaches are insufficient.
• The acetyltransferase Tip60 (encoded by Kat5) is a potential target to promote CM proliferation.

Purpose of the Study:

• To investigate the role of Tip60 in regulating cardiomyocyte differentiation and proliferation post-MI.
• To determine if Tip60 depletion affects cardiomyocyte dedifferentiation markers and epigenetic modifications.

Main Methods:

• Genetic depletion of Tip60 in a mouse model of myocardial infarction.
• Assessment of cardiomyocyte cell-cycle activation, dedifferentiation markers (EMT, metabolism), and extracellular matrix.
• Analysis of acetylated H2A.Z levels and its genomic targets using CUT&Tag.

Main Results:

• Tip60 depletion post-MI led to near obliteration of acetylated H2A.Z in CM nuclei.
• Depletion induced markers of epithelial-mesenchymal transition (EMT), extracellular matrix softening, and metabolic shifts.
• CUT&Tag revealed enrichment of acetylated H2A.Z in motifs related to CM transcription and muscle development.

Conclusions:

• Tip60 plays a critical role in maintaining cardiomyocyte differentiation and preventing proliferation.
• Tip60-mediated acetylation of H2A.Z is crucial for preserving the mature, differentiated state of cardiomyocytes.
• Targeting Tip60 may offer a novel strategy for cardiac regeneration after myocardial infarction.