Adverse epigenetic signatures by histone methyltransferase Set7 contribute to vascular dysfunction in patients with type 2 diabetes mellitus

Cyproheptadine, a SET7/9 inhibitor, reduces hyperglycaemia-induced ER stress alleviating inflammation and fibrosis in renal tubular epithelial cells

CONTEXT

Persistent hyperglycaemia increases SET7/9 expression and endoplasmic reticulum (ER) stress which causes inflammation, apoptosis, and fibrosis in renal tubular epithelial cells leading to diabetic kidney disease (DKD).

OBJECTIVE

Current study explores the renoprotective potential of a novel SET7/9 inhibitor, Cyproheptadine, and the underlying molecular mechanisms in hyperglycaemia-induced renal tubular epithelial cell injury.

METHODS

Change in expression of SET7/9, histone H3 lysine (K4) monomethylation (H3K4Me1), inflammatory, fibrotic, and ER stress proteins were evaluated in-vivo and in-vitro. NRK-52E cells were used to study the preventive effect of Cyproheptadine against hyperglycaemia-induced ER stress and subsequent inflammation and fibrosis.

RESULTS

SET7/9 and H3K4Me1 expression significantly increased with ER stress, inflammation, apoptosis, and fibrosis, in-vivo and in-vitro under hyperglycaemia. However, the cells treated with Cyproheptadine showed significant suppression of H3K4Me1 and reduction in ER stress, inflammation, apoptosis, and fibrosis.

CONCLUSION

Cyproheptadine prevented hyperglycaemia-induced renal fibrosis and inflammation by reducing H3K4Me1 expression and ER stress.

Mechanisms of Vascular Inflammation and Potential Therapeutic Targets: A Position Paper From the ESH Working Group on Small Arteries

Inflammatory responses in small vessels play an important role in the development of cardiovascular diseases, including hypertension, stroke, and small vessel disease. This involves various complex molecular processes including oxidative stress, inflammasome activation, immune-mediated responses, and protein misfolding, which together contribute to microvascular damage. In addition, epigenetic factors, including DNA methylation, histone modifications, and microRNAs influence vascular inflammation and injury. These phenomena may be acquired during the aging process or due to environmental factors. Activation of proinflammatory signaling pathways and molecular events induce low-grade and chronic inflammation with consequent cardiovascular damage. Identifying mechanism-specific targets might provide opportunities in the development of novel therapeutic approaches. Monoclonal antibodies targeting inflammatory cytokines and epigenetic drugs, show promise in reducing microvascular inflammation and associated cardiovascular diseases. In this article, we provide a comprehensive discussion of the complex mechanisms underlying microvascular inflammation and offer insights into innovative therapeutic strategies that may ameliorate vascular injury in cardiovascular disease.

Set7 Methyltransferase and Phenotypic Switch in Diabetic Glomerular Endothelial Cells

Key Points

Set7 knockout improves diabetic glomerular structure and function and prevents diabetes-induced endothelial–mesenchymal transition (EDMT) by regulating Igfbp5. Set7 knockdown prevents, and (R)-PFI-2 hydrochloride reverses, diabetes-induced EDMT by regulating insulin growth factor binding protein 5. Set7 regulates the phenotypic EDMT switch, and inhibiting the methyltransferase attenuates glomerular injury in diabetic kidney disease.

Background

Hyperglycemia influences the development of glomerular endothelial cell damage, and nowhere is this more evident than in the progression of diabetic kidney disease (DKD). While the Set7 lysine methyltransferase is a known hyperglycemic sensor, its role in endothelial cell function in the context of DKD remains poorly understood.

Methods

Single-cell transcriptomics was used to investigate Set7 regulation in a mouse model of DKD, followed by validation of findings using pharmacological and short hairpin RNA inhibition inhibition of Set7.

Results

Set7 knockout (Set7KO) improved glomerular structure and albuminuria in a mouse model of diabetes. Analysis of single-cell RNA-sequencing data showed dynamic transcriptional changes in diabetic renal cells. Set7KO controls phenotype switching of glomerular endothelial cell populations by transcriptional regulation of the insulin growth factor binding protein 5 (IGFBP5). Chromatin immunoprecipitation assays confirmed that the expression of the IGFBP5 gene was associated with mono- and dimethylation of histone H3 lysine 4 (H3K4me1/2). This generalizability was investigated in human kidney and circulating hyperglycemic cells exposed to TGFβ 1. We showed that the highly selective Set7 inhibitor (R)-PFI-2 hydrochloride attenuated indices associated with renal cell damage and mesenchymal transition, specifically (1 ) reactive oxygen species production, (2 ) IGFBP5 gene regulation, and (3 ) expression of mesenchymal markers. Furthermore, renal benefit observed in Set7KO diabetic mice closely corresponded in human glomerular endothelial cells with (R)-PFI-2 hydrochloride inhibition or Set7 short hairpin RNA silencing.

Conclusions

Set7 regulates the phenotypic endothelial–mesenchymal transition switch and suggests that targeting the lysine methyltransferase could protect glomerular cell injury in DKD.

Podcast

This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/JASN/2024_04_25_ASN0000000000000345.mp3

Repressive H3K27me3 drives hyperglycemia-induced oxidative and inflammatory transcriptional programs in human endothelium

BACKGROUND

Histone modifications play a critical role in chromatin remodelling and regulate gene expression in health and disease. Histone methyltransferases EZH1, EZH2, and demethylases UTX, JMJD3, and UTY catalyse trimethylation of lysine 27 on histone H3 (H3K27me3). This study was designed to investigate whether H3K27me3 triggers hyperglycemia-induced oxidative and inflammatory transcriptional programs in the endothelium.

METHODS

We studied human aortic endothelial cells exposed to high glucose (HAEC) or isolated from individuals with diabetes (D-HAEC). RT-qPCR, immunoblotting, chromatin immunoprecipitation (ChIP-qPCR), and confocal microscopy were performed to investigate the role of H3K27me3. We determined superoxide anion (O2-) production by ESR spectroscopy, NF-κB binding activity, and monocyte adhesion. Silencing/overexpression and pharmacological inhibition of chromatin modifying enzymes were used to modulate H3K27me3 levels. Furthermore, isometric tension studies and immunohistochemistry were performed in aorta from wild-type and db/db mice.

RESULTS

Incubation of HAEC to high glucose showed that upregulation of EZH2 coupled to reduced demethylase UTX and JMJD3 was responsible for the increased H3K27me3. ChIP-qPCR revealed that repressive H3K27me3 binding to superoxide dismutase and transcription factor JunD promoters is involved in glucose-induced O2- generation. Indeed, loss of JunD transcriptional inhibition favours NOX4 expression. Furthermore, H3K27me3-driven oxidative stress increased NF-κB p65 activity and downstream inflammatory genes. Interestingly, EZH2 inhibitor GSK126 rescued these endothelial derangements by reducing H3K27me3. We also found that H3K27me3 epigenetic signature alters transcriptional programs in D-HAEC and aortas from db/db mice.

CONCLUSIONS

EZH2-mediated H3K27me3 represents a key epigenetic driver of hyperglycemia-induced endothelial dysfunction. Targeting EZH2 may attenuate oxidative stress and inflammation and, hence, prevent vascular disease in diabetes.

Persistent epigenetic signals propel a senescence-associated secretory phenotype and trained innate immunity in CD34+ hematopoietic stem cells from diabetic patients

BACKGROUND

Diabetes-induced trained immunity contributes to the development of atherosclerosis and its complications. This study aimed to investigate in humans whether epigenetic signals involved in immune cell activation and inflammation are initiated in hematopoietic stem/progenitor cells (HSPCs) and transferred to differentiated progeny.

METHODS AND RESULTS

High glucose (HG)-exposure of cord blood (CB)-derived HSPCs induced a senescent-associated secretory phenotype (SASP) characterized by cell proliferation lowering, ROS production, telomere shortening, up-regulation of p21 and p27genes, upregulation of NFkB-p65 transcription factor and increased secretion of the inflammatory cytokines TNFα and IL6. Chromatin immunoprecipitation assay (ChIP) of p65 promoter revealed that H3K4me1 histone mark accumulation and methyltransferase SetD7 recruitment, along with the reduction of repressive H3K9me3 histone modification, were involved in NFkB-p65 upregulation of HG-HSPCs, as confirmed by increased RNA polymerase II engagement at gene level. The differentiation of HG-HSPCs into myeloid cells generated highly responsive monocytes, mainly composed of intermediate subsets (CD14hiCD16+), that like the cells from which they derive, were characterized by SASP features and similar epigenetic patterns at the p65 promoter. The clinical relevance of our findings was confirmed in sternal BM-derived HSPCs of T2DM patients. In line with our in vitro model, T2DM HSPCs were characterized by SASP profile and SETD7 upregulation. Additionally, they generated, after myeloid differentiation, senescent monocytes mainly composed of proinflammatory intermediates (CD14hiCD16+) characterized by H3K4me1 accumulation at NFkB-p65 promoter.

CONCLUSIONS

Hyperglycemia induces marked chromatin modifications in HSPCs, which, once transmitted to the cell progeny, contributes to persistent and pathogenic changes in immune cell function and composition.

Epigenetic regulation of inflammation in insulin resistance

Epigenetics focuses on the study of changes in gene expression based on modifications that do not interfere with the DNA sequence, such as DNA methylation, post-translational histone modification, and non-coding RNA. Epigenetic changes regulate the expression of many genes, including inflammatory ones. Chronic inflammation is often accompanied by insulin resistance (IR), which is characteristic of inter alia type 2 diabetes. Recently, it has been reported that altered epigenetic signature in the promoter regions of inflammatory genes may contribute to the development of IR. Therefore, the aim of this review is to present the current state of knowledge regarding the epigenetic regulation of inflammation in IR. It includes original papers published from 2014 to 2022. It appears that hypomethylation of the SOCS3 gene increases the risk of IR, while the alteration of H3K4me in the NF-kB promoter promotes changes in inflammatory phenotype. Finally, in hyperglycemic states associated with IR, altered levels of H3K4/K9m3 and H3K9/K14ac result in increased expression of the inflammatory cytokine IL-6. In addition, numerous miRNAs have been identified that may become a target in the fight against diseases related to inflammation and IR. Future studies should examine the epigenetic modifications of IR inflammatory markers associated with environmental factors.

An Updated Review on the Significance of DNA and Protein Methyltransferases and De-methylases in Human Diseases: From Molecular Mechanism to Novel Therapeutic Approaches

Epigenetic mechanisms are crucial in regulating gene expression. These mechanisms include DNA methylation and histone modifications, like methylation, acetylation, and phosphorylation. DNA methylation is associated with gene expression suppression; however, histone methylation can stimulate or repress gene expression depending on the methylation pattern of lysine or arginine residues on histones. These modifications are key factors in mediating the environmental effect on gene expression regulation. Therefore, their aberrant activity is associated with the development of various diseases. The current study aimed to review the significance of DNA and histone methyltransferases and demethylases in developing various conditions, like cardiovascular diseases, myopathies, diabetes, obesity, osteoporosis, cancer, aging, and central nervous system conditions. A better understanding of the epigenetic roles in developing diseases can pave the way for developing novel therapeutic approaches for affected patients.

Immunomodulation in diabetic wounds healing: The intersection of macrophage reprogramming and immunotherapeutic hydrogels

Diabetic wound healing presents a significant clinical challenge due to the interplay of systemic metabolic disturbances and local inflammation, which hinder the healing process. Macrophages undergo a phenotypic shift from M1 to M2 during wound healing, a transition pivotal for effective tissue repair. However, in diabetic wounds, the microenvironment disrupts this phenotypic polarization, perpetuating inflammation, and impeding healing. Reprograming macrophages to restore their M2 phenotype offers a potential avenue for modulating the wound immune microenvironment and promoting healing. This review elucidates the mechanisms underlying impaired macrophage polarization toward the M2 phenotype in diabetic wounds and discusses novel strategies, including epigenetic and metabolic interventions, to promote macrophage conversion to M2. Hydrogels, with their hydrated 3D cross-linked structure, closely resemble the physiological extracellular matrix and offer advantageous properties such as biocompatibility, tunability, and versatility. These characteristics make hydrogels promising candidates for developing immunomodulatory materials aimed at addressing diabetic wounds. Understanding the role of hydrogels in immunotherapy, particularly in the context of macrophage reprograming, is essential for the development of advanced wound care solutions. This review also highlights recent advancements in immunotherapeutic hydrogels as a step toward precise and effective treatments for diabetic wounds.

(R)-PFI-2 Analogues as Substrates and Inhibitors of Histone Lysine Methyltransferase SETD7

(R)-PFI-2 is a histone substrate-competitive inhibitor of the human histone lysine monomethyltransferase SETD7. Aimed at developing potent inhibitors of SETD7 that can also act as small molecule substrates, we replaced the pyrrolidine ring of (R)-PFI-2 with several side chains bearing nucleophilic functional groups. We explored the inhibitory activity of 20 novel (R)-PFI-2 analogues, and found that the most potent analogue has a hydroxyethyl side chain (7). SETD7's ability to catalyse methylation of (R)-PFI-2-based small molecules was evaluated by mass spectrometric assays, and we observed efficient methylation of analogues bearing lysine mimicking nucleophilic amines. The optimal side chain was found to be an aminoethyl group (1), which was surprisingly also dimethylated by SETD7. The work demonstrates that small molecules can act as both substrates and inhibitors of biomedically important SETD7.

Applicability of mesenchymal stem cell-derived exosomes as a cell-free miRNA therapy and epigenetic modifiers for diabetes

Given that exosome nanovesicles constitute various growth factors, miRNAs and lncRNAs, they have implications for epigenetic modifications. Few studies have shown that exosomes from mesenchymal stem cells (MSCs) exhibit therapeutic effects on diabetic complications by substituting miRNAs and regulating histone modifications. Therefore, reversing epigenetic aberrations in diabetes may provide new insight into its treatment. This review discusses the impact of DNA and histone methylations on the development of diabetes and its complications. Further, we talk about miRNAs dysregulated in diabetic conditions and the possibility of utilizing mesenchymal stem cell (MSC) exosomes for the development of miRNA cell-free therapy and epigenetic modifiers in reversing diabetic-induced epigenetic alterations.

Role of Epigenetics and Metabolomics in Predicting Endothelial Dysfunction in Type 2 Diabetes

Type 2 diabetes (T2D) is a worldwide health problem and cardiovascular disease (CVD) is a leading cause of morbidity and mortality in T2D patients, making the prevention of CVD onset a major priority. It is therefore crucial to optimize diagnosis and treatment to reduce this burden. Endothelial dysfunction is one of the most important prognostic factors for CVD progression, thus novel approaches to identify the early phase of endothelial dysfunction may lead to specific preventive measures to reduce the occurrence of CVD. Nowadays, multiomics approaches have provided unprecedented opportunities to stratify T2D patients into endotypes, improve therapeutic treatment and outcome and amend the survival prediction. Among omics strategies, epigenetics and metabolomics are gaining increasing interest. Recently, a dynamic correlation between metabolic pathways and gene expression through chromatin remodeling, such as DNA methylation, has emerged, indicating new perspectives on the regulatory networks impacting cellular processes. Thus, a better understanding of epigenetic-metabolite relationships can provide insight into the physiological processes altered early in the endothelium that ultimately head to disease development. Here, recent studies on epigenetics and metabolomics related to CVD prevention potentially useful to identify disease biomarkers, as well as new therapies hopefully targeting the early phase of endothelial dysfunction are highlighted.

How epigenetics impacts on human diseases

Epigenetics is a rapidly growing field of biology that studies the changes in gene expression that are not due to alterations in the DNA sequence but rather the chemical modifications of DNA and its associated proteins. Epigenetic mechanisms can profoundly influence gene expression, cell differentiation, tissue development, and disease susceptibility. Understanding epigenetic changes is essential to elucidate the mechanisms underlying the increasingly recognized role of environmental and lifestyle factors in health and disease and the intergenerational transmission of phenotypes. Recent studies suggest epigenetics may be critical in various diseases, from cardiovascular disease and cancer to neurodevelopmental and neurodegenerative disorders. Epigenetic modifications are potentially reversible and could provide new therapeutic avenues for treating these diseases using epigenetic modulators. Moreover, epigenetics provide insight into disease pathogenesis and biomarkers for disease diagnosis and risk stratification. Nevertheless, epigenetic interventions have the potential for unintended consequences and may potentially lead to increased risks of unexpected outcomes, such as adverse drug reactions, developmental abnormalities, and cancer. Therefore, rigorous studies are essential to minimize the risks associated with epigenetic therapies and to develop safe and effective interventions for improving human health. This article provides a synthetic and historical view of the origin of epigenetics and some of the most relevant achievements.

Protein posttranslational modifications in health and diseases: Functions, regulatory mechanisms, and therapeutic implications

Protein posttranslational modifications (PTMs) refer to the breaking or generation of covalent bonds on the backbones or amino acid side chains of proteins and expand the diversity of proteins, which provides the basis for the emergence of organismal complexity. To date, more than 650 types of protein modifications, such as the most well-known phosphorylation, ubiquitination, glycosylation, methylation, SUMOylation, short-chain and long-chain acylation modifications, redox modifications, and irreversible modifications, have been described, and the inventory is still increasing. By changing the protein conformation, localization, activity, stability, charges, and interactions with other biomolecules, PTMs ultimately alter the phenotypes and biological processes of cells. The homeostasis of protein modifications is important to human health. Abnormal PTMs may cause changes in protein properties and loss of protein functions, which are closely related to the occurrence and development of various diseases. In this review, we systematically introduce the characteristics, regulatory mechanisms, and functions of various PTMs in health and diseases. In addition, the therapeutic prospects in various diseases by targeting PTMs and associated regulatory enzymes are also summarized. This work will deepen the understanding of protein modifications in health and diseases and promote the discovery of diagnostic and prognostic markers and drug targets for diseases.

Targeting protein modifications in metabolic diseases: molecular mechanisms and targeted therapies

The ever-increasing prevalence of noncommunicable diseases (NCDs) represents a major public health burden worldwide. The most common form of NCD is metabolic diseases, which affect people of all ages and usually manifest their pathobiology through life-threatening cardiovascular complications. A comprehensive understanding of the pathobiology of metabolic diseases will generate novel targets for improved therapies across the common metabolic spectrum. Protein posttranslational modification (PTM) is an important term that refers to biochemical modification of specific amino acid residues in target proteins, which immensely increases the functional diversity of the proteome. The range of PTMs includes phosphorylation, acetylation, methylation, ubiquitination, SUMOylation, neddylation, glycosylation, palmitoylation, myristoylation, prenylation, cholesterylation, glutathionylation, S-nitrosylation, sulfhydration, citrullination, ADP ribosylation, and several novel PTMs. Here, we offer a comprehensive review of PTMs and their roles in common metabolic diseases and pathological consequences, including diabetes, obesity, fatty liver diseases, hyperlipidemia, and atherosclerosis. Building upon this framework, we afford a through description of proteins and pathways involved in metabolic diseases by focusing on PTM-based protein modifications, showcase the pharmaceutical intervention of PTMs in preclinical studies and clinical trials, and offer future perspectives. Fundamental research defining the mechanisms whereby PTMs of proteins regulate metabolic diseases will open new avenues for therapeutic intervention.

Essential Oils from Mediterranean Plants Inhibit In Vitro Monocyte Adhesion to Endothelial Cells from Umbilical Cords of Females with Gestational Diabetes Mellitus

Essential oils (EOs) are mixtures of volatile compounds belonging to several chemical classes derived from aromatic plants using different distillation techniques. Recent studies suggest that the consumption of Mediterranean plants, such as anise and laurel, contributes to improving the lipid and glycemic profile of patients with diabetes mellitus (DM). Hence, the aim of the present study was to investigate the potential anti-inflammatory effect of anise and laurel EOs (AEO and LEO) on endothelial cells isolated from the umbilical cord vein of females with gestational diabetes mellitus (GDM-HUVEC), which is a suitable in vitro model to reproduce the pro-inflammatory phenotype of a diabetic endothelium. For this purpose, the Gas Chromatographic/Mass Spectrometric (GC-MS) chemical profiles of AEO and LEO were first analyzed. Thus, GDM-HUVEC and related controls (C-HUVEC) were pre-treated for 24 h with AEO and LEO at 0.025% v/v, a concentration chosen among others (cell viability by MTT assay), and then stimulated with TNF-α (1 ng/mL). From the GC-MS analysis, trans-anethole (88.5%) and 1,8-cineole (53.9%) resulted as the major components of AEO and LEO, respectively. The results in C- and GDM-HUVEC showed that the treatment with both EOs significantly reduced: (i) the adhesion of the U937 monocyte to HUVEC; (ii) vascular adhesion molecule-1 (VCAM-1) protein and gene expression; (iii) Nuclear Factor-kappa B (NF-κB) p65 nuclear translocation. Taken together, these data suggest the anti-inflammatory efficacy of AEO and LEO in our in vitro model and lay the groundwork for further preclinical and clinical studies to study their potential use as supplements to mitigate vascular endothelial dysfunction associated with DM.

Vascular Aging and COVID-19

Vascular age is determined by functional and structural changes in the arterial wall. When measured by its proxy, pulse wave velocity, it has been shown to predict cardiovascular and total mortality. Disconcordance between chronological and vascular age might represent better or worse vascular health. Cell senescence is caused by oxidative stress and sustained cell replication. Senescent cells acquire senescence-associated secretory phenotype. Oxidative stress, endothelial dysfunction, dysregulation of coagulation and leucocyte infiltration are observed in the aging endothelium. All of these mechanisms lead to increased vascular calcification and stiffness. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can involve the vascular endothelium. It enters cells using angiotensin-converting enzyme 2 (ACE-2) receptors, which are abundant in endothelial cells. The damage this virus does to the endothelium can be direct or indirect. Indirect damage is caused by hyperinflammation. Direct damage results from effects on ACE-2 receptors. The reduction of ACE-2 levels seen during coronavirus disease 2019 (COVID-19) infection might cause vasoconstriction and oxidative stress. COVID-19 and vascular aging share some pathways. Due to the novelty of the virus, there is an urgent need for studies that investigate its long-term effects on vascular health.

The Role of Histone Modifications in the Pathogenesis of Diabetic Kidney Disease

Diabetic kidney disease (DKD) is the leading cause of chronic kidney disease. The pathogenesis of DKD is multifactorial, with several molecular pathways implicated. Recent data suggest that histone modification plays an important role in the development and progression of DKD. Histone modification appears to induce oxidative stress, inflammation and fibrosis in the diabetic kidney. In the present review, we summarize the current knowledge on the association between histone modification and DKD.

Methylation of the Hippo effector YAP by the methyltransferase SETD7 drives myocardial ischaemic injury: a translational study

AIMS

Methylation of non-histone proteins is emerging as a central regulatory mechanism in health and disease. The methyltransferase SETD7 has shown to methylate and alter the function of a variety of proteins in vitro; however, its function in the heart is poorly understood. The present study investigates the role of SETD7 in myocardial ischaemic injury.

METHODS AND RESULTS

Experiments were performed in neonatal rat ventricular myocytes (NRVMs), SETD7 knockout mice (SETD7-/-) undergoing myocardial ischaemia/reperfusion (I/R) injury, left ventricular (LV) myocardial samples from patients with ischaemic cardiomyopathy (ICM), and peripheral blood mononuclear cells (PBMCs) from patients with ST-elevation MI (STEMI). We show that SETD7 is activated upon energy deprivation in cultured NRVMs and methylates the Hippo pathway effector YAP, leading to its cytosolic retention and impaired transcription of antioxidant genes manganese superoxide dismutase (MnSOD) and catalase (CAT). Such impairment of antioxidant defence was associated with mitochondrial reactive oxygen species (mtROS), organelle swelling, and apoptosis. Selective pharmacological inhibition of SETD7 by (R)-PFI-2 restored YAP nuclear localization, thus preventing mtROS, mitochondrial damage, and apoptosis in NRVMs. In mice, genetic deletion of SETD7 attenuated myocardial I/R injury, mtROS, and LV dysfunction by restoring YAP-dependent transcription of MnSOD and CAT. Moreover, in cardiomyocytes isolated from I/R mice and ICM patients, (R)-PFI-2 prevented mtROS accumulation, while improving Ca2+-activated tension. Finally, SETD7 was up-regulated in PBMCs from STEMI patients and negatively correlated with MnSOD and CAT.

CONCLUSION

We show a methylation-dependent checkpoint regulating oxidative stress during myocardial ischaemia. SETD7 inhibition may represent a valid therapeutic strategy in this setting.

Epigenetics in the primary and secondary prevention of cardiovascular disease: influence of exercise and nutrition

Increasing evidence links changes in epigenetic systems, such as DNA methylation, histone modification, and non-coding RNA expression, to the occurrence of cardiovascular disease (CVD). These epigenetic modifications can change genetic function under influence of exogenous stimuli and can be transferred to next generations, providing a potential mechanism for inheritance of behavioural intervention effects. The benefits of exercise and nutritional interventions in the primary and secondary prevention of CVD are well established, but the mechanisms are not completely understood. In this review, we describe the acute and chronic epigenetic effects of physical activity and dietary changes. We propose exercise and nutrition as potential triggers of epigenetic signals, promoting the reshaping of transcriptional programmes with effects on CVD phenotypes. Finally, we highlight recent developments in epigenetic therapeutics with implications for primary and secondary CVD prevention.

Bromocriptine-QR Therapy Reduces Sympathetic Tone and Ameliorates a Pro-Oxidative/Pro-Inflammatory Phenotype in Peripheral Blood Mononuclear Cells and Plasma of Type 2 Diabetes Subjects

Bromocriptine-QR is a sympatholytic dopamine D2 agonist for the treatment of type 2 diabetes that has demonstrated rapid (within 1 year) substantial reductions in adverse cardiovascular events in this population by as yet incompletely delineated mechanisms. However, a chronic state of elevated sympathetic nervous system activity and central hypodopaminergic function has been demonstrated to potentiate an immune system pro-oxidative/pro-inflammatory condition and this immune phenotype is known to contribute significantly to the advancement of cardiovascular disease (CVD). Therefore, the possibility exists that bromocriptine-QR therapy may reduce adverse cardiovascular events in type 2 diabetes subjects via attenuation of this underlying chronic pro-oxidative/pro-inflammatory state. The present study was undertaken to assess the impact of bromocriptine-QR on a wide range of immune pro-oxidative/pro-inflammatory biochemical pathways and genes known to be operative in the genesis and progression of CVD. Inflammatory peripheral blood mononuclear cell biology is both a significant contributor to cardiovascular disease and also a marker of the body’s systemic pro-inflammatory status. Therefore, this study investigated the effects of 4-month circadian-timed (within 2 h of waking in the morning) bromocriptine-QR therapy (3.2 mg/day) in type 2 diabetes subjects whose glycemia was not optimally controlled on the glucagon-like peptide 1 receptor agonist on (i) gene expression status (via qPCR) of a wide array of mononuclear cell pro-oxidative/pro-inflammatory genes known to participate in the genesis and progression of CVD (OXR1, NRF2, NQO1, SOD1, SOD2, CAT, GSR, GPX1, GPX4, GCH1, HMOX1, BiP, EIF2α, ATF4, PERK, XBP1, ATF6, CHOP, GSK3β, NFkB, TXNIP, PIN1, BECN1, TLR2, TLR4, TLR10, MAPK8, NLRP3, CCR2, GCR, L-selectin, VCAM1, ICAM1) and (ii) humoral measures of sympathetic tone (norepinephrine and normetanephrine), whole-body oxidative stress (nitrotyrosine, TBARS), and pro-inflammatory factors (IL-1β, IL-6, IL-18, MCP-1, prolactin, C-reactive protein [CRP]). Relative to pre-treatment status, 4 months of bromocriptine-QR therapy resulted in significant reductions of mRNA levels in PBMC endoplasmic reticulum stress-unfolded protein response effectors [GRP78/BiP (34%), EIF2α (32%), ATF4 (29%), XBP1 (25%), PIN1 (14%), BECN1 (23%)], oxidative stress response proteins [OXR1 (31%), NRF2 (32%), NQO1 (39%), SOD1 (52%), CAT (26%), GPX1 (33%), GPX4 (31%), GCH1 (30%), HMOX1 (40%)], mRNA levels of TLR pro-inflammatory pathway proteins [TLR2 (46%), TLR4 (20%), GSK3β (19%), NFkB (33%), TXNIP (18%), NLRP3 (32%), CCR2 (24%), GCR (28%)], mRNA levels of pro-inflammatory cellular receptor proteins CCR2 and GCR by 24% and 28%, and adhesion molecule proteins L-selectin (35%) and VCAM1 (24%). Relative to baseline, bromocriptine-QR therapy also significantly reduced plasma levels of norepinephrine and normetanephrine by 33% and 22%, respectively, plasma pro-oxidative markers nitrotyrosine and TBARS by 13% and 10%, respectively, and pro-inflammatory factors IL-18, MCP1, IL-1β, prolactin, and CRP by 21%,13%, 12%, 42%, and 45%, respectively. These findings suggest a unique role for circadian-timed bromocriptine-QR sympatholytic dopamine agonist therapy in reducing systemic low-grade sterile inflammation to thereby reduce cardiovascular disease risk.

Epigenetic Reprogramming of the Inflammatory Response in Obesity and Type 2 Diabetes

For the past several decades, the prevalence of obesity and type 2 diabetes (T2D) has continued to rise on a global level. The risk contributing to this pandemic implicates both genetic and environmental factors, which are functionally integrated by epigenetic mechanisms. While these conditions are accompanied by major abnormalities in fuel metabolism, evidence indicates that altered immune cell functions also play an important role in shaping of obesity and T2D phenotypes. Interestingly, these events have been shown to be determined by epigenetic mechanisms. Consistently, recent epigenome-wide association studies have demonstrated that immune cells from obese and T2D individuals feature specific epigenetic profiles when compared to those from healthy subjects. In this work, we have reviewed recent literature reporting epigenetic changes affecting the immune cell phenotype and function in obesity and T2D. We will further discuss therapeutic strategies targeting epigenetic marks for treating obesity and T2D-associated inflammation.

Studying Epigenetics of Cardiovascular Diseases on Chip Guide

Epigenetics is defined as the study of inheritable changes in the gene expressions and phenotypes that occurs without altering the normal DNA sequence. These changes are mainly due to an alteration in chromatin or its packaging, which changes the DNA accessibility. DNA methylation, histone modification, and noncoding or microRNAs can best explain the mechanism of epigenetics. There are various DNA methylated enzymes, histone-modifying enzymes, and microRNAs involved in the cause of various CVDs (cardiovascular diseases) such as cardiac hypertrophy, heart failure, and hypertension. Moreover, various CVD risk factors such as diabetes mellitus, hypoxia, aging, dyslipidemia, and their epigenetics are also discussed together with CVDs such as CHD (coronary heart disease) and PAH (pulmonary arterial hypertension). Furthermore, different techniques involved in epigenetic chromatin mapping are explained. Among these techniques, the ChIP-on-chip guide is explained with regard to its role in cardiac hypertrophy, a final form of heart failure. This review focuses on different epigenetic factors that are involved in causing cardiovascular diseases.

Genetics and Epigenetics in Personalized Nutrition: Evidence, Expectations and Experiences

With the presentation of the blueprint of the first human genome in 2001 and the advent of technologies for high-throughput genetic analysis, personalized nutrition (PN) became a new scientific field and the first commercial offerings of genotype-based nutrition advice emerged at the same time. Here, we summarize the state of evidence for the effect of genetic and epigenetic factors in the development of obesity, the metabolic syndrome and resulting illnesses such as non-insulin-dependent diabetes mellitus and cardiovascular diseases. We also critically value the concepts of PN that were built around the new genetic avenue from both the academic and a commercial perspective and their effectiveness in causing sustained changes in diet, lifestyle and for improving health. Despite almost 20 years of research and commercial direct-to-consumer offerings, evidence for the success of gene-based dietary recommendations is still generally lacking. This calls for new concepts of future PN solutions that incorporate more phenotypic measures and provide a panel of instruments (e.g., self- and bio-monitoring tools, feedback systems, algorithms based on artificial intelligence) that increases compliance based on the individual´s physical and social environment and value system. This article is protected by copyright. All rights reserved.

Inflammation-Related Epigenetic Modification: The Bridge Between Immune and Metabolism in Type 2 Diabetes

T2DM, as a typical metabolic inflammatory disease, is under the joint regulation of environmental factors and genetics, combining with a variety of epigenetic changes. Apart from epigenetic changes of islet β cells and glycometabolic tissues or organs, the inflammation-related epigenetics is also the core pathomechanism leading to β-cell dysfunction and insulin resistance. In this review, we focus on the epigenetic modification of immune cells’ proliferation, recruitment, differentiation and function, providing an overview of the key genes which regulated by DNA methylation, histone modifications, and non-coding RNA in the respect of T2DM. Meanwhile, we further summarize the present situation of T2DM epigenetic research and elucidate its prospect in T2DM clinical diagnosis and treatment.

Epigenetic Modifications and Non-Coding RNA in Diabetes-Mellitus-Induced Coronary Artery Disease: Pathophysiological Link and New Therapeutic Frontiers

Diabetes mellitus (DM) is a glucose metabolism disorder characterized by chronic hyperglycemia resulting from a deficit of insulin production and/or action. DM affects more than 1 in 10 adults, and it is associated with an increased risk of cardiovascular morbidity and mortality. Cardiovascular disease (CVD) accounts for two thirds of the overall deaths in diabetic patients, with coronary artery disease (CAD) and ischemic cardiomyopathy as the main contributors. Hyperglycemic damage on vascular endothelial cells leading to endothelial dysfunction represents the main initiating factor in the pathogenesis of diabetic vascular complications; however, the underlying pathophysiological mechanisms are still not entirely understood. This review addresses the current knowledge on the pathophysiological links between DM and CAD with a focus on the role of epigenetic modifications, including DNA methylation, histone modifications and noncoding RNA control. Increased knowledge of epigenetic mechanisms has contributed to the development of new pharmacological treatments (“epidrugs”) with epigenetic targets, although these approaches present several challenges. Specific epigenetic biomarkers may also be used to predict or detect the development and progression of diabetes complications. Further studies on diabetes and CAD epigenetics are needed in order to identify possible new therapeutic targets and advance personalized medicine with the prediction of individual drug responses and minimization of adverse effects.

Metaboloepigenetics in cancer, immunity and cardiovascular disease

The influence of cellular metabolism on epigenetic pathways are well documented but misunderstood. Scientists have long known of the metabolic impact on epigenetic determinants. More often than not, that title role for DNA methylation was portrayed by the metabolite SAM or S-adenosylmethionine. Technically speaking there are many other metabolites that drive epigenetic processes that instruct seemingly distant - yet highly connect pathways - and none more so than our understanding of the cancer epigenome. Recent studies have shown that available energy link the extracellular environment to influence cellular responses. This focused review examines the recent interest in epigenomics and casts cancer, metabolism and immunity in unfamiliar roles - cooperating. There are not only language lessons from cancer research, we have come round to appreciate that reaching into areas previously thought of as too distinct are also object lessons in understanding health and disease. The Warburg effect is one such signature of how glycolysis influences metabolic shift during oncogenesis. That shift in metabolism - now recognised as central to proliferation in cancer biology - influence core enzymes that not only control gene expression but are also central to replication, condensation and the repair of nucleic acid. These nuclear processes rely on metabolism and with glucose at center stage the role of respiration and oxidative metabolism are now synonymous with the mitochondria as the powerhouses of metaboloepigenetics. The emerging evidence for metaboloepigenetics in trained innate immunity has revealed recognisable signalling pathways with antecedent extracellular stimulation. With due consideration to immunometabolism we discuss the striking signalling similarities influencing these core pathways. The immunometabolic-epigenetic axis in cardiovascular disease has deeply etched connections with inflammation and we examine the chromatin template as a carrier of epigenetic indices that determine the expression of genes influencing atherosclerosis and vascular complications of diabetes.

The BET Protein Inhibitor Apabetalone Rescues Diabetes-Induced Impairment of Angiogenic Response by Epigenetic Regulation of Thrombospondin-1

Aims: Therapeutic modulation of blood vessel growth holds promise for the prevention of limb ischemia in diabetic (DM) patients with peripheral artery disease (PAD). Epigenetic changes, namely, posttranslational histone modifications, participate in angiogenic response suggesting that chromatin-modifying drugs could be beneficial in this setting. Apabetalone (APA), a selective inhibitor of bromodomain (BRD) and bromodomain and extraterminal containing protein family (BET) proteins, prevents bromodomain-containing protein 4 (BRD4) interactions with chromatin thus modulating transcriptional programs in different organs. We sought to investigate whether APA affects angiogenic response in diabetes. Results: Compared with vehicle, APA restored tube formation and migration in human aortic endothelial cells (HAECs) exposed to high-glucose (HG) levels. Expression profiling of angiogenesis genes showed that APA prevents HG-induced upregulation of the antiangiogenic molecule thrombospondin-1 (THBS1). ChIP-seq and chromatin immunoprecipitation (ChIP) assays in HG-treated HAECs showed the enrichment of both BRD4 and active marks (H3K27ac) on THBS1 promoter, whereas BRD4 inhibition by APA prevented chromatin accessibility and THBS1 transcription. Mechanistically, we show that THBS1 inhibits angiogenesis by suppressing vascular endothelial growth factor A (VEGFA) signaling, while APA prevents these detrimental changes. In diabetic mice with hind limb ischemia, epigenetic editing by APA restored the THBS1/VEGFA axis, thus improving limb vascularization and perfusion, compared with vehicle-treated animals. Finally, epigenetic regulation of THBS1 by BRD4/H3K27ac was also reported in DM patients with PAD compared with nondiabetic controls. Innovation: This is the first study showing that BET protein inhibition by APA restores angiogenic response in experimental diabetes. Conclusions: Our findings set the stage for preclinical studies and exploratory clinical trials testing APA in diabetic PAD. Antioxid. Redox Signal. 36, 667-684.

Histone Methylation and Oxidative Stress in Cardiovascular Diseases

Oxidative stress occurs when ROS overproduction overwhelms the elimination ability of antioxidants. Accumulated studies have found that oxidative stress is regulated by histone methylation and plays a critical role in the development and progression of cardiovascular diseases. Targeting the underlying molecular mechanism to alter the interplay of oxidative stress and histone methylation may enable creative and effective therapeutic strategies to be developed against a variety of cardiovascular disorders. Recently, some drugs targeting epigenetic modifiers have been used to treat specific types of cancers. However, the comprehensive signaling pathways bridging oxidative stress and histone methylation need to be deeply explored in the contexts of cardiovascular physiology and pathology before clinical therapies be developed. In the present review, we summarize and update information on the interplay between histone methylation and oxidative stress during the development of cardiovascular diseases such as atherosclerosis, coronary artery disease, pulmonary hypertension, and diabetic macro- and microvascular pathologies.

Old and New Biomarkers Associated with Endothelial Dysfunction in Chronic Hyperglycemia

Chronic hyperglycemia and vascular damage are strictly related. Biomarkers of vascular damage have been intensively studied in the recent years in the quest of reliable cardiovascular risk assessment tools able to facilitate risk stratification and early detection of vascular impairment. The present study is a narrative review with the aim of revising the available evidence on current and novel markers of hyperglycemia-induced vascular damage. After a discussion of classic tools used to investigate endothelial dysfunction, we provide an in-depth description of novel circulating biomarkers (chemokines, extracellular vesicles, and epigenetic and metabolomic biomarkers). Appropriate use of a single as well as a cluster of the discussed biomarkers might enable in a near future (a) the prompt identification of targeted and customized treatment strategies and (b) the follow-up of cardiovascular treatment efficacy over time in clinical research and/or in clinical practice.

Non-histone methylation of SET7/9 and its biological functions

BACKGROUND

(su(var)-3-9,enhancer-of-zeste,trithorax) domain-containing protein 7/9 (SET7/9) is a member of the protein lysine methyltransferases (PLMTs or PKMTs) family. It contains a SET domain. Recent studies demonstrate that SET7/9 methylates both lysine 4 of histone 3 (H3-K4) and lysine(s) of non-histone proteins, including transcription factors, tumor suppressors, and membrane-associated receptors.

OBJECTIVE

This article mainly reviews the non-histone methylation effects of SET7/9 and its functions in tumorigenesis and development.

METHODS

PubMed was screened for this information.

RESULTS

SET7/9 plays a key regulatory role in various biological processes such as cell proliferation, transcription regulation, cell cycle, protein stability, cardiac morphogenesis, and development. In addition, SET7/9 is involved in the pathogenesis of hair loss, breast cancer progression, human carotid plaque atherosclerosis, chronic kidney disease, diabetes, obesity, ovarian cancer, prostate cancer, hepatocellular carcinoma, and pulmonary fibrosis.

CONCLUSION

SET7/9 is an important methyltransferase, which can catalyze the methylation of a variety of proteins. Its substrates are closely related to the occurrence and development of tumors.

Gene regulation of intracellular adhesion molecule-1 (ICAM-1): A molecule with multiple functions

Intracellular adhesion molecule 1 (ICAM-1) is one of the most extensively studied inducible cell adhesion molecules which is responsible for several immune functions like T cell activation, extravasation, inflammation, etc. The molecule is constitutively expressed over the cell surface and is regulated up / down in response to inflammatory mediators like cellular stress, proinflammatory cytokines, viral infection. These stimuli modulate the expression of ICAM-1 primarily through regulating the ICAM-1 gene transcription. On account of the presence of various binding sites for NF-κB, AP-1, SP-1, and many other transcription factors, the architecture of the ICAM-1 promoter become complex. Transcription factors in union with other transcription factors, coactivators, and suppressors promote their assembly in a stereospecific manner on ICAM-1 promoter which mediates ICAM-1 regulation in response to different stimuli. Along with transcriptional regulation, epigenetic modifications also play a pivotal role in controlling ICAM-1 expression on different cell types. In this review, we summarize the regulation of ICAM-1 expression both at the transcriptional as well as post-transcriptional level with an emphasis on transcription factors and signaling pathways involved.

Insulin Resistance and Cancer: In Search for a Causal Link

Insulin resistance (IR) is a condition which refers to individuals whose cells and tissues become insensitive to the peptide hormone, insulin. Over the recent years, a wealth of data has made it clear that a synergistic relationship exists between IR, type 2 diabetes mellitus, and cancer. Although the underlying mechanism(s) for this association remain unclear, it is well established that hyperinsulinemia, a hallmark of IR, may play a role in tumorigenesis. On the other hand, IR is strongly associated with visceral adiposity dysfunction and systemic inflammation, two conditions which favor the establishment of a pro-tumorigenic environment. Similarly, epigenetic modifications, such as DNA methylation, histone modifications, and non-coding RNA, in IR states, have been often associated with tumorigenesis in numerous types of human cancer. In addition to these observations, it is also broadly accepted that gut microbiota may play an intriguing role in the development of IR-related diseases, including type 2 diabetes and cancer, whereas potential chemopreventive properties have been attributed to some of the most commonly used antidiabetic medications. Herein we provide a concise overview of the most recent literature in this field and discuss how different but interrelated molecular pathways may impact on tumor development.

The β Cell in Diabetes: Integrating Biomarkers With Functional Measures

The pathogenesis of hyperglycemia observed in most forms of diabetes is intimately tied to the islet β cell. Impairments in propeptide processing and secretory function, along with the loss of these vital cells, is demonstrable not only in those in whom the diagnosis is established but typically also in individuals who are at increased risk of developing the disease. Biomarkers are used to inform on the state of a biological process, pathological condition, or response to an intervention and are increasingly being used for predicting, diagnosing, and prognosticating disease. They are also proving to be of use in the different forms of diabetes in both research and clinical settings. This review focuses on the β cell, addressing the potential utility of genetic markers, circulating molecules, immune cell phenotyping, and imaging approaches as biomarkers of cellular function and loss of this critical cell. Further, we consider how these biomarkers complement the more long-established, dynamic, and often complex measurements of β-cell secretory function that themselves could be considered biomarkers.

Histone Methylation Related Therapeutic Challenge in Cardiovascular Diseases

The epidemic of cardiovascular diseases (CVDs) is predicted to spread rapidly in advanced countries accompanied by the high prevalence of risk factors. In terms of pathogenesis, the pathophysiology of CVDs is featured by multiple disorders, including vascular inflammation accompanied by simultaneously perturbed pathways, such as cell death and acute/chronic inflammatory reactions. Epigenetic alteration is involved in the regulation of genome stabilization and cellular homeostasis. The association between CVD progression and histone modifications is widely known. Among the histone modifications, histone methylation is a reversible process involved in the development and homeostasis of the cardiovascular system. Abnormal methylation can promote CVD progression. This review discusses histone methylation and the enzymes involved in the cardiovascular system and determine the effects of histone methyltransferases and demethylases on the pathogenesis of CVDs. We will further demonstrate key proteins mediated by histone methylation in blood vessels and review histone methylation-mediated cardiomyocytes and cellular functions and pathways in CVDs. Finally, we will summarize the role of inhibitors of histone methylation and demethylation in CVDs and analyze their therapeutic potential, based on previous studies.

Intermittent High Glucose Elevates Nuclear Localization of EZH2 to Cause H3K27me3-Dependent Repression of KLF2 Leading to Endothelial Inflammation

Epigenetic mechanisms have emerged as one of the key pathways promoting diabetes-associated complications. Herein, we explored the role of enhancer of zeste homolog 2 (EZH2) and its product histone 3 lysine 27 trimethylation (H3K27me3) in high glucose-mediated endothelial inflammation. To examine this, we treated cultured primary endothelial cells (EC) with different treatment conditions-namely, constant or intermittent or transient high glucose. Intermittent high glucose maximally induced endothelial inflammation by upregulating transcript and/or protein-level expression of ICAM1 and P-selectin and downregulating eNOS, KLF2, and KLF4 protein levels. We next investigated the underlining epigenetic mechanisms responsible for intermittent hyperglycemia-dependent endothelial inflammation. Compared with other high glucose treatment groups, intermittent high glucose-exposed EC exhibited an increased level of H3K27me3 caused by reduction in EZH2 threonine 367 phosphorylation and nuclear retention of EZH2. Intermittent high glucose also promoted polycomb repressive complex-2 (PRC2) assembly and EZH2's recruitment to histone H3. Abrupt enrichment of H3K27me3 on KLF2 and KLF4 gene promoters caused repression of these genes, further supporting endothelial inflammation. In contrast, reducing H3K27me3 through small molecule and/or siRNA-mediated inhibition of EZH2 rescued KLF2 level and inhibited endothelial inflammation in intermittent high glucose-challenged cultured EC and isolated rat aorta. These findings indicate that abrupt chromatin modifications cause high glucose-dependent inflammatory switch of EC.

Multi-omics profiling: the way towards precision medicine in metabolic diseases

Metabolic diseases including type 2 diabetes mellitus (T2DM), non-alcoholic fatty liver disease (NAFLD), and metabolic syndrome (MetS) are alarming health burdens around the world, while therapies for these diseases are far from satisfying as their etiologies are not completely clear yet. T2DM, NAFLD, and MetS are all complex and multifactorial metabolic disorders based on the interactions between genetics and environment. Omics studies such as genetics, transcriptomics, epigenetics, proteomics, and metabolomics are all promising approaches in accurately characterizing these diseases. And the most effective treatments for individuals can be achieved via omics pathways, which is the theme of precision medicine. In this review, we summarized the multi-omics studies of T2DM, NAFLD, and MetS in recent years, provided a theoretical basis for their pathogenesis and the effective prevention and treatment, and highlighted the biomarkers and future strategies for precision medicine.

Assessment and pathophysiology of microvascular disease: recent progress and clinical implications

The development of novel, non-invasive techniques and standardization of protocols to assess microvascular dysfunction have elucidated the key role of microvascular changes in the evolution of cardiovascular (CV) damage, and their capacity to predict an increased risk of adverse events. These technical advances parallel with the development of novel biological assays that enabled the ex vivo identification of pathways promoting microvascular dysfunction, providing novel potential treatment targets for preventing cerebral-CV disease. In this article, we provide an update of diagnostic testing strategies to detect and characterize microvascular dysfunction and suggestions on how to standardize and maximize the information obtained from each microvascular assay. We examine emerging data highlighting the significance of microvascular dysfunction in the development CV disease manifestations. Finally, we summarize the pathophysiology of microvascular dysfunction emphasizing the role of oxidative stress and its regulation by epigenetic mechanisms, which might represent potential targets for novel interventions beyond conventional approaches, representing a new frontier in CV disease reduction.

The metabolic-epigenetic nexus in type 2 diabetes mellitus

The prevalence of type 2 diabetes mellitus (T2DM) continues to rise globally. Yet the aetiology and pathophysiology of this noncommunicable, polygenic disease, is poorly understood. Lifestyle factors, such as poor dietary intake, lack of exercise, and abnormal glycaemia, are purported to play a role in disease onset and progression, and these environmental factors may disrupt specific epigenetic mechanisms, leading to a reprogramming of gene transcription. The hyperglycaemic cell per se, alters epigenetics through chemical modifications to DNA and histones via metabolic intermediates such as succinate, α-ketoglutarate and O-GlcNAc. To illustrate, α-ketoglutarate is considered a salient co-factor in the activation of the ten-eleven translocation (TET) dioxygenases, which drives DNA demethylation. On the contrary, succinate and other mitochondrial tricarboxylic acid cycle intermediates, inhibit TET activity predisposing to a state of hypermethylation. Hyperglycaemia depletes intracellular ascorbic acid, and damages DNA by enhancing the production of reactive oxygen species (ROS); this compromised cell milieu exacerbates the oxidation of 5-methylcytosine alongside a destabilisation of TET. These metabolic connections may regulate DNA methylation, affecting gene transcription and pancreatic islet β-cell function in T2DM. This complex interrelationship between metabolism and epigenetic alterations may provide a conceptual foundation for understanding how pathologic stimuli modify and control the intricacies of T2DM. As such, this narrative review will comprehensively evaluate and detail the interplay between metabolism and epigenetic modifications in T2DM.

Epigenetic Remodeling in Obesity-Related Vascular Disease

Significance: The prevalence of obesity and cardiometabolic phenotypes is alarmingly increasing across the globe and is associated with atherosclerotic vascular complications and high mortality. In spite of multifactorial interventions, vascular residual risk remains high in this patient population, suggesting the need for breakthrough therapies. The mechanisms underpinning obesity-related vascular disease remain elusive and represent an intense area of investigation. Recent Advances: Epigenetic modifications-defined as environmentally induced chemical changes of DNA and histones that do not affect DNA sequence-are emerging as a potent modulator of gene transcription in the vasculature and might significantly contribute to the development of obesity-induced endothelial dysfunction. DNA methylation and histone post-translational modifications cooperate to build complex epigenetic signals, altering transcriptional networks that are implicated in redox homeostasis, mitochondrial function, vascular inflammation, and perivascular fat homeostasis in patients with cardiometabolic disturbances. Critical Issues: Deciphering the epigenetic landscape in the vasculature is extremely challenging due to the complexity of epigenetic signals and their function in regulating transcription. An overview of the most important epigenetic pathways is required to identify potential molecular targets to treat or prevent obesity-related endothelial dysfunction and atherosclerotic disease. This would enable the employment of precision medicine approaches in this setting. Future Directions: Current and future research efforts in this field entail a better definition of the vascular epigenome in obese patients as well as the unveiling of novel, cell-specific chromatin-modifying drugs that are able to erase specific epigenetic signals that are responsible for maladaptive transcriptional alterations and vascular dysfunction in obese patients. Antioxid. Redox Signal. 34, 1165-1199.

Cell-specific epigenetic changes in atherosclerosis

Atherosclerosis is a disease of large and medium arteries that can lead to life-threatening cerebrovascular and cardiovascular consequences such as heart failure and stroke and is a major contributor to cardiovascular-related mortality worldwide. Atherosclerosis development is a complex process that involves specific structural, functional and transcriptional changes in different vascular cell populations at different stages of the disease. The application of single-cell RNA sequencing (scRNA-seq) analysis has discovered not only disease-related cell-specific transcriptomic profiles but also novel subpopulations of cells once thought as homogenous cell populations. Vascular cells undergo specific transcriptional changes during the entire course of the disease. Epigenetics is the instruction-set-architecture in living cells that defines and maintains the cellular identity by regulating the cellular transcriptome. Although different cells contain the same genetic material, they have different epigenomic signatures. The epigenome is plastic, dynamic and highly responsive to environmental stimuli. Modifications to the epigenome are driven by an array of epigenetic enzymes generally referred to as writers, erasers and readers that define cellular fate and destiny. The reversibility of these modifications raises hope for finding novel therapeutic targets for modifiable pathological conditions including atherosclerosis where the involvement of epigenetics is increasingly appreciated. This article provides a critical review of the up-to-date research in the field of epigenetics mainly focusing on in vivo settings in the context of the cellular role of individual vascular cell types in the development of atherosclerosis.

Epigenetics, microRNA and Metabolic Syndrome: A Comprehensive Review

Epigenetics refers to the DNA chemistry changes that result in the modification of gene transcription and translation independently of the underlying DNA coding sequence. Epigenetic modifications are reported to involve various molecular mechanisms, including classical epigenetic changes affecting DNA methylation and histone modifications and small RNA-mediated processes, particularly that of microRNAs. Epigenetic changes are reversible and are closely interconnected. They are recognised to play a critical role as mediators of gene regulation, and any alteration in these mechanisms has been identified to mediate various pathophysiological conditions. Moreover, genetic predisposition and environmental factors, including dietary alterations, lifestyle or metabolic status, are identified to interact with the human epigenome, highlighting the importance of epigenetic factors as underlying processes in the aetiology of various diseases such as MetS. This review will reflect on how both the classical and microRNA-regulated epigenetic changes are associated with the pathophysiology of metabolic syndrome. We will then focus on the various aspects of epigenetic-based strategies used to modify MetS outcomes, including epigenetic diet, epigenetic drugs, epigenome editing tools and miRNA-based therapies.

Diabetes and Metabolic Drivers of Trained Immunity

Accumulating evidence shows how diverse physiological functions, such as metabolism, immunity, tissue homeostasis, and hematopoiesis, are intricately and profoundly intertwined at multiple levels. This brief review will present evidence from a rapidly expanding field of immunometabolism, highlighting how cells that are relevant to processes at play in determining vascular health and disease can be programmed by changes in their metabolic environment. It will focus on how such changes can be imprinted or trained, particularly through epigenetic modifications, such that adaptations driven by metabolic signals can cause persistent changes in cell function, even after the original stimulus has been corrected or removed. Recognition of these processes and elucidation of the mechanisms underlying them stand to have far-reaching implications for the diagnosis and treatment of diabetes and related metabolic states.

Methyltransferase SET domain family and its relationship with cardiovascular development and diseases

Abnormal epigenetic modification is closely related to the occurrence and development of cardiovascular diseases. The SET domain (SETD) family is an important epigenetic modifying enzyme containing SETD. They mainly affect gene expression by methylating H3K4, H3K9, H3K36 and H4K20. Additionally, the SETD family catalyzes the methylation of non-histone proteins, thereby affects the signal transduction of signal transduction and activator of transcription (STAT) 1, Wnt/β-catenin, hypoxia-inducible factor (HIF)-1α and Hippo/YAP pathways. The SETD family has the following regulatory effects on cardiovascular development and diseases: regulating coronary artery formation and cardiac development; protecting cardiac tissue from ischemia reperfusion injury; regulating inflammation, oxidative stress and apoptosis in cardiovascular complications of diabetes; participating in the formation of pulmonary hypertension; regulating thrombosis, cardiac hypertrophy and arrhythmia. This article summarizes the basic structures, expression regulation mechanisms and the role of existing SETD family members in cardiovascular development and diseases, in order to provide a basis for understanding the molecular mechanism of cardiovascular disease and exploring the therapeutic targets.

The Diabetes Syndrome - A Collection of Conditions with Common, Interrelated Pathophysiologic Mechanisms

The four basic pathophysiologic mechanisms which damage the β-cell within diabetes (ie, genetic and epigenetic changes, inflammation, an abnormal environment, and insulin resistance [IR]) also contribute to cell and tissue damage and elevate the risk of developing all typical diabetes-related complications. Genetic susceptibility to damage from abnormal external and internal environmental factors has been described including inflammation and IR. All these mechanisms can promote epigenetic changes, and in total, these pathophysiologic mechanisms interact and react with each other to cause damage to cells and tissues ultimately leading to disease. Importantly, these pathophysiologic mechanisms also serve to link other common conditions including cancer, dementia, psoriasis, atherosclerotic cardiovascular disease (ASCVD), nonalcoholic fatty liver disease (NAFLD), and nonalcoholic steatohepatitis (NASH). The “Diabetes Syndrome”, an overarching group of interrelated conditions linked by these overlapping mechanisms, can be viewed as a conceptual framework that can facilitate understanding of the inter-relationships of superficially disparate conditions. Recognizing the association of the conditions within the Diabetes Syndrome due to common pathophysiologies has the potential to provide both benefit to the patient (eg, prevention, early detection, precision medicine) and to the advancement of medicine (eg, driving education, research, and dynamic decision-based medical practice).

Dicarbonyl stress, protein glycation and the unfolded protein response

The reactive dicarbonyl metabolite, methylglyoxal (MG), is increased in obesity and diabetes and is implicated in the development of insulin resistance, type 2 diabetes mellitus and vascular complications of diabetes. Dicarbonyl stress is the metabolic state of abnormal high MG concentration. MG is an arginine-directed glycating agent and precursor of the major advanced glycation endproduct, arginine-derived hydroimidazolone MG-H1. MG-H1 is often formed on protein surfaces and an uncharged hydrophobic residue, inducing protein structural distortion and misfolding. Recent studies indicate that dicarbonyl stress in human endothelial cells and fibroblasts in vitro induced a proteomic response consistent with activation of the unfolded protein response (UPR). The response included: increased abundance of heat shock proteins and ubiquitin ligases catalysing the removal of proteins with unshielded surface hydrophobic patches and formation of polyubiquitinated chains to encapsulate misfolded proteins; and increased low grade inflammation. Activation of the UPR is implicated in insulin resistance. An effective strategy to counter increased MG is inducing increased expression of glyoxalase-1 (Glo1). An optimized inducer of Glo1 expression, trans-resveratrol and hesperetin combination, normalized increased MG concentration, corrected insulin resistance and decreased low grade inflammation in overweight and obese subjects. We propose that dicarbonyl stress, through increased formation of MG-glycated proteins, may be an important physiological stimulus of the UPR and Glo1 inducers may provide a route to effective suppression and therapy. With further investigation and validation, this may provide key new insight into physiological activators of the UPR and association with dicarbonyl stress.

The Endothelium as a Target for Anti-Atherogenic Therapy: A Focus on the Epigenetic Enzymes EZH2 and SIRT1

Endothelial cell inflammatory activation and dysfunction are key events in the pathophysiology of atherosclerosis, and are associated with an elevated risk of cardiovascular events. Yet, therapies specifically targeting the endothelium and atherosclerosis are lacking. Here, we review how endothelial behaviour affects atherogenesis and pose that the endothelium may be an efficacious cellular target for antiatherogenic therapies. We discuss the contribution of endothelial inflammatory activation and dysfunction to atherogenesis and postulate that the dysregulation of specific epigenetic enzymes, EZH2 and SIRT1, aggravate endothelial dysfunction in a pleiotropic fashion. Moreover, we propose that commercially available drugs are available to clinically explore this postulation.

The Epigenome in Atherosclerosis

Emerging evidence suggests the growing importance of "nongenetic factors" in the pathogenesis of atherosclerotic vascular disease. Indeed, the inherited genome determines only part of the risk profile as genomic approaches do not take into account additional layers of biological regulation by "epi"-genetic changes. Epigenetic modifications are defined as plastic chemical changes of DNA/histone complexes which critically affect gene activity without altering the DNA sequence. These modifications include DNA methylation, histone posttranslational modifications, and non-coding RNAs and have the ability to modulate gene expression at both transcriptional and posttranscriptional level. Notably, epigenetic signals are mainly induced by environmental factors (i.e., pollution, smoking, noise) and, once acquired, may be transmitted to the offspring. The inheritance of adverse epigenetic changes may lead to premature deregulation of pathways involved in vascular damage and endothelial dysfunction. Here, we describe the emerging role of epigenetic modifications as fine-tuners of gene transcription in atherosclerosis. Specifically, the following aspects are described in detail: (1) discovery and impact of the epigenome in cardiovascular disease, (2) the epigenetic landscape in atherosclerosis; (3) inheritance of epigenetic signals and premature vascular disease; (4) epigenetic control of lipid metabolism, vascular oxidative stress, inflammation, autophagy, and apoptosis; (5) epigenetic biomarkers in patients with atherosclerosis; (6) novel therapeutic strategies to modulate epigenetic marks. Understanding the individual epigenetic profile may pave the way for new approaches to determine cardiovascular risk and to develop personalized therapies to treat atherosclerosis and its complications.

Phytochemicals as Potential Epidrugs in Type 2 Diabetes Mellitus

Type 2 diabetes Mellitus (T2DM) prevalence has significantly increased worldwide in recent years due to population age, obesity, and modern sedentary lifestyles. The projections estimate that 439 million people will be diabetic in 2030. T2DM is characterized by an impaired β-pancreatic cell function and insulin secretion, hyperglycemia and insulin resistance, and recently the epigenetic regulation of β-pancreatic cells differentiation has been underlined as being involved. It is currently known that several bioactive molecules, widely abundant in plants used as food or infusions, have a key role in histone modification and DNA methylation, and constituted potential epidrugs candidates against T2DM. In this sense, in this review the epigenetic mechanisms involved in T2DM and protein targets are reviewed, with special focus in studies addressing the potential use of phytochemicals as epidrugs that prevent and/or control T2DM in vivo and in vitro. As main findings, and although some controversial results have been found, bioactive molecules with epigenetic regulatory function, appear to be a potential replacement/complementary therapy of pharmacological hypoglycemic drugs, with minimal side effects. Indeed, natural epidrugs have shown to prevent or delay the T2DM development and the morbidity associated to dysfunction of blood vessels, eyes and kidneys due to sustained hyperglycemia in T2DM patients.

Epigenetic Histone Modifications in the Pathogenesis of Diabetic Kidney Disease

Diabetic kidney disease (DKD), as the main complication of diabetes mellitus, is the primary cause of the end-stage renal disease (ESRD) and the most common chronic kidney disease. Overall, 30-40% of patients with type 1 and type 2 diabetes eventually develop DKD. Although some diabetes patients have intensified glycemic control, they still develop diabetic kidney disease. Current treatment methods can alleviate but do not markedly halt disease development, resulting in renal failure and severe complications, even contributing to elevated morbidity and mortality rates. DKD is a disease with interactions of genes and the environment. Emerging evidence indicates that DKD-associated key genes are also regulated by the epigenetic mechanism. Recently, increasing researches involving cells and experimental animals demonstrated that histone post-translational modifications can mediate gene expression, which correlated with diabetic kidney disease. Novel therapeutic strategies for epigenetic events could be beneficial for the early detection and treatment of DKD to prevent it from developing into end-stage renal disease (ESRD). In this review, we discuss prior findings in the field of histone modifications in DKD, especially histone acetylation and histone methylation. We then focus on recent developments in histone acetylation and methylation involved in the pathogenesis of DKD.

Differential epigenetic factors in the prediction of cardiovascular risk in diabetic patients

Hyperglycaemia can strongly alter the epigenetic signatures in many types of human vascular cells providing persistent perturbations of protein–protein interactions both in micro- and macro-domains. The establishment of these epigenetic changes may precede cardiovascular (CV) complications and help us to predict vascular lesions in diabetic patients. Importantly, these epigenetic marks may be transmitted across several generations (transgenerational effect) and increase the individual risk of disease. Aberrant DNA methylation and imbalance of histone modifications, mainly acetylation and methylation of H3, represent key determinants of vascular lesions and, thus, putative useful biomarkers for prevention and diagnosis of CV risk in diabetics. Moreover, a differential expression of some micro-RNAs (miRNAs), mainly miR-126, may be a useful prognostic biomarker for atherosclerosis development in asymptomatic subjects. Recently, also environmental-induced chemical perturbations in mRNA (epitranscriptome), mainly the N⁶-methyladenosine, have been associated with obesity and diabetes. Importantly, reversal of epigenetic changes by modulation of lifestyle and use of metformin, statins, fenofibrate, and apabetalone may offer useful therapeutic options to prevent or delay CV events in diabetics increasing the opportunity for personalized therapy. Network medicine is a promising molecular-bioinformatic approach to identify the signalling pathways underlying the pathogenesis of CV lesions in diabetic patients. Moreover, machine learning tools combined with tomography are advancing the individualized assessment of CV risk in these patients. We remark the need for combining epigenetics and advanced bioinformatic platforms to improve the prediction of vascular lesions in diabetics increasing the opportunity for CV precision medicine.