Promoter methylation changes in ALOX12 and AIRE1: novel epigenetic markers for atherosclerosis

Upregulation of ALOX12-12-HETE pathway impairs AMPK-dependent modulation of vascular metabolism in ApoE/LDLR-/- mice

Mitochondrial dysfunction and 12-lipoxygenase (ALOX12)-derived 12(S)-HETE production have been associated with vascular inflammation and the pathogenesis of atherosclerosis. However, the role of ALOX12 in regulating vascular energy metabolism in vascular inflammation has not been studied to date. Using mitochondrial and glycolysis functional profiling with the Seahorse extracellular flux analyzer, metabolipidomics, and proteomic analysis (LC-MS/MS), we characterized alterations in vascular energy metabolism in 2- and 6-month-old ApoE/LDLR-/- vs. control C57BL/6 mice. We identified that aorta of 6-month-old ApoE/LDLR-/- mice displayed compromised mitochondrial metabolism manifested by the reduced expression of mitochondrial enzymes, impaired mitochondrial respiration, and consequently diminished respiratory reserve capacity. An increased flux through the glycolysis/lactate shuttle, the hexosamine biosynthetic pathway (HBP), and the pentose phosphate pathway (PPP) was also recognized. Interestingly, ALOX12-12-HETE was the most upregulated axis in eicosanoid metabolism and histological examinations indicated that ApoE/LDLR-/- mice showed increased aortic expression of ALOX12, particularly in early atherosclerotic plaque areas. Remarkably, the joint blocking of ALOX12 and activation of AMPK, but not AMPK activation alone, resulted in the reprogramming of vascular metabolism, with improved mitochondrial respiration and suppressed auxiliary pathways (HBP, PPP, itaconate shunt). In conclusion, excessive activation of the ALOX12-12-HETE pathway in vascular inflammation in early atherosclerosis inhibits AMPK-dependent regulation of vascular metabolism. Consequently, ALOX12 may represent a novel target to boost impaired vascular mitochondrial function in pro-atherosclerotic vascular inflammation.

Zhilong Huoxue Tongyu capsule protects against atherosclerosis by suppressing EndMT via modulating Hippo/YAP signaling pathway

Background and aim

Zhilong Huoxue Tongyu Capsule (ZL capsule) has been demonstrated to be an effective and widely-used traditional Chinese medicine (TCM) formula for the treatment of various diseases, especially for atherosclerosis (AS) related cardiovascular and cerebrovascular diseases. Reversal of endothelial-mesenchymal transition (EndMT) plays a crucial role in the cure of AS. But the curative impact of ZL capsule on EndMT remains obscure during the development of AS. The purpose of this study is to explore the effect of ZL capsule on AS and to study the regulation mechanism on EndMT in AS by ZL capsule in vivo and in vitro.

Experimental procedure

An in vivo model of AS was induced in ApoE-/- mice by administrating them with an 8-week period of high-fat diet (HFD). After oral gavage of different doses of ZL capsule and Atorvastatin calcium tablets (ATO) for 4 weeks, the lipid levels, plaque area, lipid deposition, and EndMT were evaluated using standard assays. In order to simulate EndMT in vitro, human umbilical vein endothelial cells (HUVECs) were subjected to oxidized low-density lipoprotein (ox-LDL). Western blotting (WB) and immunofluorescence techniques were used to evaluate the intervention effect of ZL capsule on EndMT and Hippo/YAP pathways.

Results and conclusion

ZL capsule demonstrated therapeutic effects on dyslipidemia and EndMT among atherosclerotic mice. To be specific, ZL capusle diminished the total cholesterol (TC), total triglyceride (TG) and low-density lipoprotein (LDL-C) levels, whereas increased that of high-density lipoproteins (HDL-C). Meanwhile, ZL capusle upregulated the expression of endothelial markers (CD31 and VE-cadherin) and reduced that of mesenchymal markers (ɑ-SMA and FSP1), indicating that ZL capusle could inhibit EndMT during the development of AS. Furthermore, molecular docking results indicated that active ingredients including formononetin, calycosin, astragaloside III, astragaloside A in ZL capsule have strong affinity with YAP proteins, and ZL capsule can significantly repress the initiation of Hippo/YAP pathway during AS. In conclusion, ZL capsule effectively attenuated AS progression by exerting inhibitory effects on EndMT through modulation of the Hippo/YAP signaling pathway.

miR-520e and its promoter region DNA methylation as potential biomarkers in atherosclerosis

In atherosclerosis, DNA methylation plays a key regulatory role in the expression of related genes. However, the molecular mechanisms of these processes in human umbilical vein endothelial cells (HUVECs) are unclear. Here, using high-throughput sequencing from the Infinium HumanMethylation450 assay, we manifested that the cg19564375 methylation of miR-520e promoter region in the peripheral blood of acute coronary syndrome (ACS) patients was higher than that of healthy controls. As shown by RQ-MSP, the upstream DNA methylation level of the miR-520e promoter region was considerably increased in ACS patients. miR-520e was markedly downregulated in ACS patients compared with healthy controls. In the oxidized low-density lipoprotein (ox-LDL)-induced HUVECs injury model, DNA methylation of the upstream region of miR-520e was significantly increased. With increasing concentrations of the methylase inhibitor 5-Aza, miR-520e expression was upregulated. The silence of methyltransferase DNMT1, rather than DNMT3a or DNMT3b, abolished the influence of miR-520e expression by ox-LDL treatment in HUVECs. A dual luciferase reporter assay revealed that miR-520e regulated the TGFBR2 3'-untranslated region region. After silencing TGFBR2, the promoting effect of miR-520e inhibitor on cell proliferation and migration may be attenuated. In conclusion, the expression of miR-520e is modified by its promoter region DNA methylation, and miR-520e and its promoter region DNA methylation may be potential biomarkers in atherosclerosis.

Genetic effects on the skin methylome in healthy older twins

Whole-skin DNA methylation variation has been implicated in several diseases, including melanoma, but its genetic basis has not yet been fully characterized. Using bulk skin tissue samples from 414 healthy female UK twins, we performed twin-based heritability and methylation quantitative trait loci (meQTL) analyses for >400,000 DNA methylation sites. We find that the human skin DNA methylome is on average less heritable than previously estimated in blood and other tissues (mean heritability: 10.02%). meQTL analysis identified local genetic effects influencing DNA methylation at 18.8% (76,442) of tested CpG sites, as well as 1,775 CpG sites associated with at least one distal genetic variant. As a functional follow-up, we performed skin expression QTL (eQTL) analyses in a partially overlapping sample of 604 female twins. Colocalization analysis identified over 3,500 shared genetic effects affecting thousands of CpG sites (10,067) and genes (4,475). Mediation analysis of putative colocalized gene-CpG pairs identified 114 genes with evidence for eQTL effects being mediated by DNA methylation in skin, including in genes implicating skin disease such as ALOX12 and CSPG4. We further explored the relevance of skin meQTLs to skin disease and found that skin meQTLs and CpGs under genetic influence were enriched for multiple skin-related genome-wide and epigenome-wide association signals, including for melanoma and psoriasis. Our findings give insights into the regulatory landscape of epigenomic variation in skin.

The roles of B cells in cardiovascular diseases

Damage to the heart can start the repair process and cause cardiac remodeling. B cells play an important role in this process. B cells are recruited to the injured place and activate cardiac remodeling through secreting antibodies and cytokines. Different types of B cells showed specific functions in the heart. Among all types of B cells, heart-associated B cells play a vital role in the heart by secreting TGFβ1. B cells participate in the activation of fibroblasts and promote cardiac fibrosis. Four subtypes of B cells in the heart revealed the relationship between the B cells' heterogeneity and cardiac remodeling. Many cardiovascular diseases like atherosclerosis, heart failure (HF), hypertension, myocardial infarction (MI), and dilated cardiomyopathy (DCM) are related to B cells. The primary mechanisms of these B cell-related activities will be discussed in this review, which may also suggest potential novel therapeutic targets.

Molecular genomic and epigenomic characteristics related to aspirin and clopidogrel resistance

BACKGROUND

Mediators, genomic and epigenomic characteristics involving in metabolism of arachidonic acid by cyclooxygenase (COX) and lipoxygenase (ALOX) and hepatic activation of clopidogrel have been individually suggested as factors associated with resistance against aspirin and clopidogrel. The present multi-center prospective cohort study evaluated whether the mediators, genomic and epigenomic characteristics participating in arachidonic acid metabolism and clopidogrel activation could be factors that improve the prediction of the aspirin and clopidogrel resistance in addition to cardiovascular risks.

METHODS

We enrolled 988 patients with transient ischemic attack and ischemic stroke who were evaluated for a recurrence of ischemic stroke to confirm clinical resistance, and measured aspirin (ARU) and P2Y12 reaction units (PRU) using VerifyNow to assess laboratory resistance 12 weeks after aspirin and clopidogrel administration. We investigated whether mediators, genotypes, and promoter methylation of genes involved in COX and ALOX metabolisms and clopidogrel activation could synergistically improve the prediction of ischemic stroke recurrence and the ARU and PRU levels by integrating to the established cardiovascular risk factors.

RESULTS

The logistic model to predict the recurrence used thromboxane A synthase 1 (TXAS1, rs41708) A/A genotype and ALOX12 promoter methylation as independent variables, and, improved sensitivity of recurrence prediction from 3.4% before to 13.8% after adding the mediators, genomic and epigenomic variables to the cardiovascular risks. The linear model we used to predict the ARU level included leukotriene B4, COX2 (rs20417) C/G and thromboxane A2 receptor (rs1131882) A/A genotypes with the addition of COX1 and ALOX15 promoter methylations as variables. The linear PRU prediction model included G/A and prostaglandin I receptor (rs4987262) G/A genotypes, COX2 and TXAS1 promoter methylation, as well as cytochrome P450 2C19*2 (rs4244285) A/A, G/A, and *3 (rs4986893) A/A genotypes as variables. The linear models for predicting ARU (r = 0.291, R2 = 0.033, p < 0.01) and PRU (r = 0.503, R2 = 0.210, p < 0.001) levels had improved prediction performance after adding the genomic and epigenomic variables to the cardiovascular risks.

CONCLUSIONS

This study demonstrates that different mediators, genomic and epigenomic characteristics of arachidonic acid metabolism and clopidogrel activation synergistically improved the prediction of the aspirin and clopidogrel resistance together with the cardiovascular risk factors.

TRIAL REGISTRATION

URL: https://www.

CLINICALTRIALS

gov ; Unique identifier: NCT03823274.

DNA methylation and stroke prognosis: an epigenome-wide association study

BACKGROUND AND AIMS

Stroke is the leading cause of adult-onset disability. Although clinical factors influence stroke outcome, there is a significant variability among individuals that may be attributed to genetics and epigenetics, including DNA methylation (DNAm). We aimed to study the association between DNAm and stroke prognosis.

METHODS AND RESULTS

To that aim, we conducted a two-phase study (discovery-replication and meta-analysis) in Caucasian patients with ischemic stroke from two independent centers (BasicMar [discovery, N = 316] and St. Pau [replication, N = 92]). Functional outcome was assessed using the modified Rankin Scale (mRS) at three months after stroke, being poor outcome defined as mRS > 2. DNAm was determined using the 450K and EPIC BeadChips in whole-blood samples collected within the first 24 h. We searched for differentially methylated positions (DMPs) in 370,344 CpGs, and candidates below p-value < 10-5 were subsequently tested in the replication cohort. We then meta-analyzed DMP results from both cohorts and used them to identify differentially methylated regions (DMRs). After doing the epigenome-wide association study, we found 29 DMPs at p-value < 10-5 and one of them was replicated: cg24391982, annotated to thrombospondin-2 (THBS2) gene (p-valuediscovery = 1.54·10-6; p-valuereplication = 9.17·10-4; p-valuemeta-analysis = 6.39·10-9). Besides, four DMRs were identified in patients with poor outcome annotated to zinc finger protein 57 homolog (ZFP57), Arachidonate 12-Lipoxygenase 12S Type (ALOX12), ABI Family Member 3 (ABI3) and Allantoicase (ALLC) genes (p-value < 1·10-9 in all cases).

DISCUSSION

Patients with poor outcome showed a DMP at THBS2 and four DMRs annotated to ZFP57, ALOX12, ABI3 and ALLC genes. This suggests an association between stroke outcome and DNAm, which may help identify new stroke recovery mechanisms.

Hypomethylation in MTNR1B: a novel epigenetic marker for atherosclerosis profiling using stenosis radiophenotype and blood inflammatory cells

BACKGROUND

Changes in gene-specific promoter methylation may result from aging and environmental influences. Atherosclerosis is associated with aging and environmental effects. Thus, promoter methylation profiling may be used as an epigenetic tool to evaluate the impact of aging and the environment on atherosclerosis development. However, gene-specific methylation changes are currently inadequate epigenetic markers for predicting atherosclerosis and cardiovascular disease pathogenesis.

RESULTS

We profiled and validated changes in gene-specific promoter methylation associated with atherosclerosis using stenosis radiophenotypes of cranial vessels and blood inflammatory cells rather than direct sampling of atherosclerotic plaques. First, we profiled gene-specific promoter methylation changes using digital restriction enzyme analysis of methylation (DREAM) sequencing in peripheral blood mononuclear cells from eight samples each of cranial vessels with and without severe-stenosis radiophenotypes. Using DREAM sequencing profiling, 11 tags were detected in the promoter regions of the ACVR1C, ADCK5, EFNA2, ENOSF1, GLS2, KNDC1, MTNR1B, PACSIN3, PAX8-AS1, TLDC1, and ZNF7 genes. Using methylation evaluation, we found that EFNA2, ENOSF1, GLS2, KNDC1, MTNR1B, PAX8-AS1, and TLDC1 showed > 5% promoter methylation in non-plaque intima, atherosclerotic vascular tissues, and buffy coats. Using logistic regression analysis, we identified hypomethylation of MTNR1B as an independent variable for the stenosis radiophenotype prediction model by combining it with traditional atherosclerosis risk factors including age, hypertension history, and increases in creatinine, lipoprotein (a), and homocysteine. We performed fivefold cross-validation of the prediction model using 384 patients with ischemic stroke (50 [13%] no-stenosis and 334 [87%] > 1 stenosis radiophenotype). For the cross-validation, the training dataset included 70% of the dataset. The prediction model showed an accuracy of 0.887, specificity to predict stenosis radiophenotype of 0.940, sensitivity to predict no-stenosis radiophenotype of 0.533, and area under receiver operating characteristic curve of 0.877 to predict stenosis radiophenotype from the test dataset including 30% of the dataset.

CONCLUSIONS

We identified and validated MTNR1B hypomethylation as an epigenetic marker to predict cranial vessel atherosclerosis using stenosis radiophenotypes and blood inflammatory cells rather than direct atherosclerotic plaque sampling.

Detection of Ferroptosis by Immunohistochemistry and Immunofluorescence

Ferroptosis is a type of regulated cell death driven by oxidative damage, characterized by iron overload and lipid peroxidation, and regulated by a network of distinct molecules and organelles. Impaired ferroptotic response is implicated in multiple physiological and pathological processes, including tumorigenesis, neurodegeneration, and ischemia-reperfusion damage. Classical techniques of immunohistochemistry (IHC) and immunofluorescence (IF) can be employed to exhibit antigen expression and location in tissues observed with microscopy, making them powerful tools in studying the ferroptosis process. In this chapter, we introduce commonly used protocols and summarize typical markers used in IHC and IF to monitor ferroptosis.

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.

Ambient air pollution during pregnancy and DNA methylation in umbilical cord blood, with potential mediation of associations with infant adiposity: The Healthy Start study

BACKGROUND

Prenatal exposure to ambient air pollution has been associated with adverse offspring health outcomes. Childhood health effects of prenatal exposures may be mediated through changes to DNA methylation detectable at birth.

METHODS

Among 429 non-smoking women in a cohort study of mother-infant pairs in Colorado, USA, we estimated associations between prenatal exposure to ambient fine particulate matter (PM2.5) and ozone (O3), and epigenome-wide DNA methylation of umbilical cord blood cells at delivery (2010-2014). We calculated average PM2.5 and O3 in each trimester of pregnancy and the full pregnancy using inverse-distance-weighted interpolation. We fit linear regression models adjusted for potential confounders and cell proportions to estimate associations between air pollutants and methylation at each of 432,943 CpGs. Differentially methylated regions (DMRs) were identified using comb-p. Previously in this cohort, we reported positive associations between 3rd trimester O3 exposure and infant adiposity at 5 months of age. Here, we quantified the potential for mediation of that association by changes in DNA methylation in cord blood.

RESULTS

We identified several DMRs for each pollutant and period of pregnancy. The greatest number of significant DMRs were associated with third trimester PM2.5 (21 DMRs). No single CpGs were associated with air pollutants at a false discovery rate <0.05. We found that up to 8% of the effect of 3rd trimester O3 on 5-month adiposity may be mediated by locus-specific methylation changes, but mediation estimates were not statistically significant.

CONCLUSIONS

Differentially methylated regions in cord blood were identified in association with maternal exposure to PM2.5 and O3. Genes annotated to the significant sites played roles in cardiometabolic disease, immune function and inflammation, and neurologic disorders. We found limited evidence of mediation by DNA methylation of associations between third trimester O3 exposure and 5-month infant adiposity.

Theories and Molecular Basis of Vascular Aging: A Review of the Literature from VascAgeNet Group on Pathophysiological Mechanisms of Vascular Aging

Vascular aging, characterized by structural and functional alterations of the vascular wall, is a hallmark of aging and is tightly related to the development of cardiovascular mortality and age-associated vascular pathologies. Over the last years, extensive and ongoing research has highlighted several sophisticated molecular mechanisms that are involved in the pathophysiology of vascular aging. A more thorough understanding of these mechanisms could help to provide a new insight into the complex biology of this non-reversible vascular process and direct future interventions to improve longevity. In this review, we discuss the role of the most important molecular pathways involved in vascular ageing including oxidative stress, vascular inflammation, extracellular matrix metalloproteinases activity, epigenetic regulation, telomere shortening, senescence and autophagy.

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.

Making sense of the ageing methylome

Over time, the human DNA methylation landscape accrues substantial damage, which has been associated with a broad range of age-related diseases, including cardiovascular disease and cancer. Various age-related DNA methylation changes have been described, including at the level of individual CpGs, such as differential and variable methylation, and at the level of the whole methylome, including entropy and correlation networks. Here, we review these changes in the ageing methylome as well as the statistical tools that can be used to quantify them. We detail the evidence linking DNA methylation to ageing phenotypes and the longevity strategies aimed at altering both DNA methylation patterns and machinery to extend healthspan and lifespan. Lastly, we discuss theories on the mechanistic causes of epigenetic ageing.

A Signature for Smoking Status of Coronary Heart Disease Patients through Weighted Gene Coexpression Network Analysis

Background. Smoking is one of the risk factors of coronary heart disease (CHD), while its underlying mechanism is less well defined. Purpose. To identify and testify 6 key genes of CHD related to smoking through weighted gene coexpression network analysis (WGCNA), protein-protein interaction (PPI) network analysis, and pathway analysis. Methods. CHD patients’ samples were first downloaded from Gene Expression Omnibus (GEO). Then, genes of interest were obtained after analysis of variance (ANOVA). Thereafter, 23 coexpressed modules that were determined after genes with similar expression were incorporated via WGCNA. The biological functions of genes in the modules were researched by enrichment analysis. Pearson correlation analysis and PPI network analysis were used to screen core genes related to smoking in CHD. Results. The violet module was the most significantly associated with smoking ( $r=-0.28$ , $p=0.006$ ). Genes in this module mainly participated in biological functions related to the heart. Altogether, 6 smoking-related core genes were identified through bioinformatics analyses. Their expressions in animal models were detected through the animal experiment. Conclusion. This study identified 6 core genes to serve as underlying biomarkers for monitoring and predicting smoker’s CHD risk.

DNA methylome profiling reveals epigenetic regulation of lipoprotein-associated phospholipase A2 in human vulnerable atherosclerotic plaque

BACKGROUND

Atherosclerotic plaque vulnerability is a key feature of atheroprogression and precipitating acute cardiovascular events. Although the pivotal role of epigenetic regulation in atherosclerotic plaque destabilization is being recognized, the DNA methylation profile and its potential role in driving the progression and destabilization of atherosclerotic cardiovascular disease remains largely unknown. We conducted a genome-wide analysis to identify differentially methylated genes in vulnerable and non-vulnerable atherosclerotic lesions to understand more about pathogenesis.

RESULTS

We compared genome-wide DNA methylation profiling between carotid artery plaques of patients with clinically symptomatic (recent stroke or transient ischemic attack) and asymptomatic disease (no recent stroke) using Infinium Methylation BeadChip arrays, which revealed 90,368 differentially methylated sites (FDR < 0.05, |delta beta|> 0.03) corresponding to 14,657 annotated genes. Among these genomic sites, 30% were located at the promoter regions and 14% in the CpG islands, according to genomic loci and genomic proximity to the CpG islands, respectively. Moreover, 67% displayed hypomethylation in symptomatic plaques, and the differentially hypomethylated genes were found to be involved in various aspects of inflammation. Subsequently, we focus on CpG islands and revealed 14,596 differentially methylated sites (|delta beta|> 0.1) located at the promoter regions of 7048 genes. Integrated analysis of methylation and gene expression profiles identified that 107 genes were hypomethylated in symptomatic plaques and showed elevated expression levels in both advanced plaques and ruptured plaques. The imprinted gene PLA2G7, which encodes lipoprotein-associated phospholipase A₂ (Lp-PLA₂), was one of the top hypomethylated genes with an increased expression upon inflammation. Further, the hypomethylated CpG site at the promoter region of PLA2G7 was identified as cg11874627, demethylation of which led to increased binding of Sp3 and expression of Lp-PLA₂ through bisulfate sequencing, chromatin immunoprecipitation assay and enzyme-linked immunosorbent assay. These effects were further enhanced by deacetylase.

CONCLUSION

Extensive DNA methylation modifications serve as a new and critical layer of biological regulation that contributes to atheroprogression and destabilization via inflammatory processes. Revelation of this hitherto unknown epigenetic regulatory mechanism could rejuvenate the prospects of Lp-PLA₂ as a therapeutic target to stabilize the atherosclerotic plaque and reduce clinical sequelae.

Ferroptosis: the potential value target in atherosclerosis

In advanced atherosclerosis (AS), defective function-induced cell death leads to the formation of the characteristic necrotic core and vulnerable plaque. The forms and mechanisms of cell death in AS have recently been elucidated. Among them, ferroptosis, an iron-dependent form of necrosis that is characterized by oxidative damage to phospholipids, promotes AS by accelerating endothelial dysfunction in lipid peroxidation. Moreover, disordered intracellular iron causes damage to macrophages, vascular smooth muscle cells (VSMCs), vascular endothelial cells (VECs), and affects many risk factors or pathologic processes of AS such as disturbances in lipid peroxidation, oxidative stress, inflammation, and dyslipidemia. However, the mechanisms through which ferroptosis initiates the development and progression of AS have not been established. This review explains the possible correlations between AS and ferroptosis, and provides a reliable theoretical basis for future studies on its mechanism.

LncRNA-TCONS_00034812 is upregulated in atherosclerosis and upregulates miR-21 through methylation in vascular smooth muscle cells

Background

LncRNA-TCONS_00034812 is a critical player in the proliferation of aortic smooth muscle cells. It is known that artery injury plays an important role in atherosclerosis. However, the potential implication of LncRNA-TCONS_00034812 in atherosclerosis remains unclear. In this study, we collected artery specimens from patients with atherosclerosis and healthy controls to investigate the involvement of LncRNA-TCONS_00034812 in atherosclerosis.

Methods

Sixty patients with atherosclerosis and 60 controls, admitted at The First Hospital of Changsha (Changsha, China), between March 2017 and March 2019, were included. An artery biopsy was performed on all participants to obtain the artery specimens. Real-time quantitative PCR were performed to quantify the relative expression level of LncRNA-TCONS_00034812. Its role in atherosclerotic lesion was evaluated in (high fat diet) HFD-induced ApoE^−/− mice. Moreover, human aortic smooth muscle cells (HAOSMCs) was employed to study functional role of LncRNA-TCONS_00034812 overexpression and knockdown by methylation-specific PCR and cell proliferation assay.

Results

Overexpression of TCONS_00034812 resulted in miR-21 upregulation and a decrease of miR-21 gene methylation. In contrast, silencing of TCONS_00034812 caused miR-21 downregulation and an increase of miR-21 gene methylation. Cell proliferation analysis indicated that the overexpression of TCONS_00034812 and miR-21 promoted cell proliferation, while silencing of TCONS_00034812 played an opposite role. Moreover, miR-21 overexpression weakened the effects of silencing TCONS_00034812 on cell proliferation.

Conclusions

In summary, LncRNA-TCONS_00034812 is upregulated in atherosclerotic samples, and its overexpression upregulates miR-21 through methylation in human aortic smooth muscle cells (HAOSMCs). Our study indicates that LncRNA-TCONS_00034812 could serve as a potential biomarker for diagnosis of atherosclerosis.