Epigenetics in atherosclerosis: key features and therapeutic implications

In silico and in vitro analysis of microRNAs with therapeutic potential in atherosclerosis

Atherosclerosis is a chronic inflammatory disease in which aberrant lipid metabolism plays a key role. MicroRNAs (miRNAs), micro-coordinators of gene expression, have been recently proposed as novel clinical biomarkers and potential therapeutic tools for a broad spectrum of diseases. This study aimed to identify miRNAs with therapeutic potential in atherosclerosis. Bioinformatic databases, including experimentally validated and computational prediction tools as well as a novel combination method, were used to identify miRNAs that are able to simultaneously inhibit key genes related to the pathogenesis of atherosclerosis. Further validation of genes and miRNAs was conducted using the STRING online tool, KEGG pathway analysis and DIANA-miRPath. The inhibitory effects of the identified miRNAs in HepG2 and Huh7 cells were verified by real-time PCR. The MTT assay was utilized to evaluate cell cytotoxicity effects of miRNAs. Atherosclerotic drug-targeted genes were selected as key genes. Strong interactions between genes were confirmed using STRING. These genes were shown to be integral to critical pathological processes involved in atherosclerosis. A novel combined method of validated and predicted tools for the identification of effective miRNAs was defined as the combination score (C-Score). Bioinformatic analysis showed that hsa-miR-124-3p and hsa-miR-16-5p possessed the best C-Score (0.68 and 0.62, respectively). KEGG and DIANA-miRPath analysis showed that selected genes and identified miRNAs were involved in atherosclerosis-related pathways. Compared with the controls in both HepG2 and Huh7 cell lines, miR-124 significantly reduced the expression of CETP, PCSK9, MTTP, and APOB, and miR-16 significantly reduced the expression of APOCIII, CETP, HMGCR, PCSK9, MTTP, and APOB, respectively. The cytotoxicity assay showed that miR-124 reduced cell viability, especially after 72 h; however, miR-16 did not show any significant cytotoxicity in either cell line. Our findings indicate that hsa-miR-124 and miR-16 have potential for use as therapeutic candidates in the treatment of atherosclerosis.

Vulnerable Atherosclerotic Plaque: Is There a Molecular Signature?

Atherosclerosis and its clinical manifestations, coronary and cerebral artery diseases, are the most common cause of death worldwide. The main pathophysiological mechanism for these complications is the rupture of vulnerable atherosclerotic plaques and subsequent thrombosis. Pathological studies of the vulnerable lesions showed that more frequently, plaques rich in lipids and with a high level of inflammation, responsible for mild or moderate stenosis, are more prone to rupture, leading to acute events. Identifying the vulnerable plaques helps to stratify patients at risk of developing acute vascular events. Traditional imaging methods based on plaque appearance and size are not reliable in prediction the risk of rupture. Intravascular imaging is a novel technique able to identify vulnerable lesions, but it is invasive and an operator-dependent technique. This review aims to summarize the current data from literature regarding the main biomarkers involved in the attempt to diagnose vulnerable atherosclerotic lesions. These biomarkers could be the base for risk stratification and development of the new therapeutic drugs in the treatment of patients with vulnerable atherosclerotic plaques.

Clinical Parameters and Epigenetic Biomarkers of Plaque Vulnerability in Patients with Carotid Stenosis

Atheromatous disease is the first cause of death and dependency in developed countries and carotid artery atherosclerosis is one of the main causes of severe ischaemic strokes. Current management strategies are mainly based on the degree of stenosis and patient selection has limited accuracy. This information could be complemented by the identification of biomarkers of plaque vulnerability, which would permit patients at greater and lesser risk of stroke to be distinguished, thus enabling a better selection of patients for surgical or intensive medical treatment. Although several circulating protein-based biomarkers with significance for both the diagnosis of carotid artery disease and its prognosis have been identified, at present, none have been clinically implemented. This review focuses especially on the most relevant clinical parameters to take into account in routine clinical practice and summarises the most up-to-date data on epigenetic biomarkers of carotid atherosclerosis and plaque vulnerability.

The critical role of epigenetic mechanism in PM2.5-induced cardiovascular diseases

Cardiovascular disease (CVD) has become the leading cause of death worldwide, which seriously threatens human life and health. Epidemiological studies have confirmed the occurrence and development of CVD are closely related to air pollution. In particular, fine particulate matter (PM_2.5) is recognized as an important environmental factor contributing to increased morbidity, mortality and hospitalization rates among adults and children. However, the underlying mechanism by which PM_2.5 promotes CVD development remains unclear. With the development of epigenetics, recent studies have shown that PM_2.5 exposure may induce or aggravate CVD through epigenetic changes. In order to better understand the potential mechanisms, this paper reviews the epigenetic changes of CVD caused by PM_2.5. We summarized the epigenetic mechanisms of PM_2.5 causing cardiovascular pathological damage and functional changes, mainly involving DNA methylation, non-coding RNA, histone modification and chromosome remodeling. It will provide important clues for exploring the biological mechanisms affecting cardiovascular health.