Search

Atherosclerosis (AS) is a progressive disease of multifactorial origin, which occurs in response to endothelial injury. Increased homocysteine (Hcy) is considered a major cause of endothelial dysfunction, oxidative stress and DNA methylation; however, the mechanisms remain to be fully elucidated. The aim of the present study was to investigate whether Hcy causes injury to endothelial cells (ECs) by the effect of lectin-like oxidized-low density lipoprotein receptor-1 (LOX-1) DNA methylation through toll-like receptor 4(TLR4)/nuclear factor (NF)-κB/DNA methyltransferase (DNMT)1. The ECs were treated with different concentrations of Hcy, and it was found that Hcy promoted the expression of TLR4, leading to EC injury. The effect of oxidative stress was analyzed by measuring superoxide dismutase, malondialdehyde and hydrogen peroxide in the ECs. In addition, the association between NF-κB and DNMT1 was examined by treatment of the ECs with pyrrolidine dithiocarbamate (PDTC). The results suggested that Hcy induced LOX-1 DNA hypomethyaltion to promote the expression levels of LOX-1. Taken together, Hcy injured the ECs through the effect of methylation and trans-sulfuration metabolism of LOX-1 through TLR4/NF-κB/DNMT1. Following injury to the ECs, lipids, particularly ox-LDL, accumulated in the sub-endothelial layer to promote the formation of AS. [ABSTRACT FROM AUTHOR]

Vascular smooth muscle cell (VSMC) proliferation is a primary pathological event in atherosclerosis (AS), and homocysteine (Hcy) is an independent risk factor for AS. However, the underlying mechanisms are still lagging. Studies have used the combination of methylation of promoters of multiple genes to diagnose tumors, thus the aim of the current study was to investigate the role of methylation status of several genes in VSMCs treated with Hcy. CpG islands were identified in the promoters of platelet‑derived growth factor (PDGF), p53, phosphatase and tensin homologue on chromosome 10 (PTEN) and mitofusin 2 (MFN2). Hypomethylation was observed to occur in the promoter region of PDGF, hypermethylation in p53, PTEN and MFN2, and hypomethylation in two global methylation indicators, aluminium (Alu) and long interspersed nucleotide element‑1 (Line‑1). This was accompanied by an increase in the expression of PDGF, and reductions of p53, PTEN and MFN2, both in mRNA and protein levels. An elevation of S‑adenosylmethionine (SAM) and a reduction of S‑adenosylhomocysteine (SAH) and the SAM/SAH ratio were also identified. In conclusion, Hcy impacted methylation the of AS‑associated genes and global methylation status that mediate the cell proliferation, which may be a character of VSMCs treated with Hcy. The data provided evidence for mechanisms of VSMCs proliferation in AS induced by Hcy and may provide a new perspective for AS induced by Hcy. [ABSTRACT FROM AUTHOR]

The aim of the present study was to identify an effective method for detecting early-phase atherosclerosis (AS), as well as to provide useful DNA methylation profiles to serve as biomarkers for the detection of AS. A total of 300 individuals (150 AS patients and 150 healthy subjects) were recruited for peripheral blood DNA methylation analyses at 12 gene promoter loci using nested methylation-specific polymerase chain reaction in a test set. Based on the test set, the promoter methylation of TIMP metallopeptidase inhibitor 1 (TIMP1), ATP binding cassette subfamily A member 1 (ABCA1), and acetyl-CoA acetyltransferase 1 (ACAT1) were determined to be candidate biomarkers; demonstrating the highest sensitivity (88%) and specificity (90%). The biomarkers that were candidates for early AS detection were validated in an independent validation set (n=100). In the validation set, the combination of T1MP1, ABCA1 and ACAT1 methylation achieved sensitivity, specificity and coincidence rate values of 88, 70 and 79%, respectively. In the current pilot study, the patterns of DNA methylation of AS-associated genes were observed to be significantly altered in the peripheral blood of AS patients. Thus, the AS-specific methylation of the three-gene panel (TIMP1, ABCA1, and ACAT1) may serve as a valuable biomarker for the early detection of AS. [ABSTRACT FROM AUTHOR]

Accumulating evidence has suggested that homocysteine (Hcy) is an independent risk factor for atherosclerosis (AS). Hcy can promote vascular smooth muscle cell (VSMC) proliferation, which is pivotal in the pathogenesis and progression of AS. The aim of the present study was to investigate the epigenetic regulatory mechanism of microRNA (miR).143.mediated VSMCs proliferation induced by Hcy. The results of a 3.(4,5.dimethylthiazol.2.yl).2,5.diphe.nyltetrazolium bromide assay revealed that VSMC proliferation was increased by 1.39.fold following treatment with 100 mM Hcy, compared with the control group. The levels of miR.143 were markedly downregulated in the Hcy group, compared with the control group, as determined using reverse transcription.quantitative polymerase chain reaction analysis. In addition, the level of miR.143 methylation was increased markedly in the VSMCs treated with Hcy, compared with the control, and was reduced following transfection with DNA methyltransferase (DNMT)3a small interfering RNA, determined using methylation.specific.PCR. The activities of DNMT3a luciferase were also altered accordingly in VSMCs transfected with pre-miR-143 and miR-143 inhibitor, respectively. In addition, the expression of miR-143 was observed to be inversely correlated with the mRNA and protein expression of DNMT3 in the VSMCs. Taken together, these findings suggest that DNMT3a is a direct target of miR-143, and that the upregulation of DNMT3 is responsible for the hypermethylation of miR-143 in Hcy-induced VSMC proliferation. [ABSTRACT FROM AUTHOR]