The mechanisms of
homocysteine-mediated cardiac threats are poorly understood.
Homocysteine, being the precursor to S-adenosyl
methionine (a methyl donor) through
methionine, is indirectly involved in methylation phenomena for
DNA,
RNA, and
protein. We reported previously that cardiac-specific deletion of
N-methyl-d-aspartate receptor-1 (
NMDAR1) ameliorates
homocysteine-posed cardiac threats, and in this study, we aim to explore the role of
NMDAR1 in epigenetic mechanisms of
heart failure, using cardiomyocytes during
hyperhomocysteinemia (HHcy). High
homocysteine levels activate
NMDAR1, which consequently leads to abnormal DNA methylation vs.
histone acetylation through modulation of
DNA methyltransferase 1 (DNMT1), HDAC1,
miRNAs, and MMP9 in cardiomyocytes. HL-1 cardiomyocytes cultured in Claycomb media were treated with 100 μM
homocysteine in a dose-dependent manner.
NMDAR1 antagonist (
MK801) was added in the absence and presence of
homocysteine at 10 μM in a dose-dependent manner. The expression of DNMT1,
histone deacetylase 1 (HDAC1),
NMDAR1,
microRNA (miR)-133a, and miR-499 was assessed by real-time PCR as well as Western blotting. Methylation and acetylation levels were determined by checking 5'-methylcytosine DNA methylation and
chromatin immunoprecipitation. Hyperhomocysteinemic mouse models (CBS+/-) were used to confirm the results in vivo. In HHcy, the expression of
NMDAR1, DNMT1, and
matrix metalloproteinase 9 increased with increase in H3K9 acetylation, while HDAC1, miR-133a, and miR-499 decreased in cardiomyocytes. Similar results were obtained in heart tissue of CBS+/- mouse. High
homocysteine levels instigate cardiovascular remodeling through
NMDAR1, miR-133a, miR-499, and DNMT1. A decrease in HDAC1 and an increase in H3K9 acetylation and DNA methylation are suggestive of chromatin remodeling in HHcy.