DNAmethylation is an epigenetic mechanism regulating gene expression. In this study, we observed that DNAmethyltransferase 3a (Dnmt3a) expression is decreased after muscle atrophy.Wemade skeletalmuscle-specific Dnmt3a-knockout (Dnmt3a-KO) mice. The regeneration capacity after muscle injury was markedly decreased in Dnmt3a-KOmice.DiminishedmRNAand protein expression of Dnmt3awere observed in skeletalmuscles aswell as in satellite cells, which are important formuscle regeneration, in Dnmt3a-KOmice. Dnmt3a-KO satellite cell showed smaller in size (length/area), suggesting suppressed myotube differentiation. Microarray analysis of satellite cells showed that expression of growth differentiation factor 5 (Gdf5)mRNAwasmarkedly increased in Dnmt3a-KOmice. TheDNA methylation level of the Gdf5 promoter wasmarkedly decreased in Dnmt3a-KO satellite cells. In addition, DNA methylation inhibitor azacytidine treatment increased Gdf5 expression in wild-type satellite cells, suggesting Gdf5 expression is regulated byDNAmethylation. Also, we observed increased inhibitor of differentiation (a target of Gdf5)mRNA expression in Dnmt3a-KO satellite cells. Thus, Dnmt3a appears to regulate satellite cell differentiation viaDNAmethylation. Thismechanism may play a role in the decreased regeneration capacity during atrophy such as in aged sarcopenia.
All Science Journal Classification (ASJC) codes
- Molecular Biology