MicroRNA-200a Inhibits Inflammation and Atherosclerotic Lesion Formation by Disrupting EZH2-Mediated Methylation of STAT3

Interplay between epigenetic mechanisms and transcription factors in atherosclerosis

Cardiovascular diseases (CVD), including coronary heart disease and stroke, comprise the number one cause of mortality worldwide. A major contributor to CVD is atherosclerosis, which is a low-grade inflammatory disease of vasculature that involves a pathological build-up of plaque within the arterial walls. Studies have shown that regulation of gene expression via transcription factors and epigenetic mechanisms play a fundamental role in transcriptomic changes linked to the development of atherosclerosis. Chromatin remodeling is a reversible phenomenon and studies have supported the clinical application of chromatin-modifying agents for the prevention and treatment of CVD. In addition, pre-clinical studies have identified multiple transcription factors as potential therapeutic targets in combating atherosclerotic CVD. Although interaction between transcription factors and epigenetic mechanisms facilitate gene regulation, a limited number of studies appreciate this crosstalk in the context of CVD. Here, we reviewed this gene regulatory mechanism underappreciated in atherosclerosis, which will highlight the mechanisms underlying novel therapeutics targeting epigenetic modifiers and transcription factors in atherosclerosis.

Shear-Sensitive circRNA-LONP2 Promotes Endothelial Inflammation and Atherosclerosis by Targeting NRF2/HO1 Signaling

Hemodynamic shear stress is a frictional force that acts on vascular endothelial cells and is essential for endothelial homeostasis. Physiological laminar shear stress (LSS) suppresses endothelial inflammation and protects arteries from atherosclerosis. Herein, we screened differentially expressed circular RNAs (circRNAs) that were significantly altered in LSS-stimulated endothelial cells and found that circRNA-LONP2 was involved in modulating the flow-dependent inflammatory response. Furthermore, endothelial circRNA-LONP2 overexpression promoted endothelial inflammation and atherosclerosis in vitro and in vivo. Mechanistically, circRNA-LONP2 competitively sponged miR-200a-3p and subsequently promoted Kelch-like ECH-associated protein 1, Yes-associated protein 1, and enhancer of zeste homolog 2 expression, thereby inactivating nuclear factor erythroid 2-related factor 2/heme oxygenase-1 signaling, promoting oxidative stress and endothelial inflammation, and accelerating atherosclerosis. LSS-induced down-regulation of circRNA-LONP2 suppresses endothelial inflammation, at least in part, by activating the miR-200a-3p-mediated nuclear factor erythroid 2-related factor 2/heme oxygenase-1 signaling pathway. CircRNA-LONP2 may serve as a new therapeutic target for atherosclerosis.

Role of transcriptional cofactors in cardiovascular diseases

Cardiovascular disease is a main cause of mortality in the world and the highest incidence of all diseases. However, the mechanism of the pathogenesis of cardiovascular disease is still unclear, and we need to continue to explore its mechanism of action. The occurrence and development of cardiovascular disease is significantly associated with genetic abnormalities, and gene expression is affected by transcriptional regulation. In this complex process, the protein-protein interaction promotes the RNA polymerase II to the initiation site. And in this process of transcriptional regulation, transcriptional cofactors are responsible for passing cues from enhancers to promoters and promoting the binding of RNA polymerases to promoters, so transcription cofactors playing a key role in gene expression regulation. There is growing evidence that transcriptional cofactors play a critical role in cardiovascular disease. Transcriptional cofactors can promote or inhibit transcription by affecting the function of transcription factors. It can affect the initiation and elongation process of transcription by forming complexes with transcription factors, which are important for the stabilization of DNA rings. It can also act as a protein that interacts with other proteins to affect the expression of other genes. Therefore, the aim of this overview is to summarize the effect of some transcriptional cofactors such as BRD4, EP300, MED1, EZH2, YAP, SIRT6 in cardiovascular disease and to provide a promising therapeutic strategy for the treatment of cardiovascular disease.

Downregulation of HMGB1 carried by macrophage-derived extracellular vesicles delays atherosclerotic plaque formation through Caspase-11-dependent macrophage pyroptosis

BACKGROUND

Macrophage-derived extracellular vesicle (macrophage-EV) is highly studied for its regulatory role in atherosclerosis (AS). Our current study tried to elucidate the possible role of macrophage-EV loaded with small interfering RNA against high-mobility group box 1 (siHMGB1) affecting atherosclerotic plaque formation.

METHODS

In silico analysis was performed to find critical factors in mouse atherosclerotic plaque formation. EVs secreted by RAW 264.7 cells were collected by ultracentrifugation and characterized, followed by the preparation of macrophage-EV-loaded siHMGB1 (macrophage-EV/siHMGB1). ApoE-/- mice were used to construct an AS mouse model by a high-fat diet, followed by injection of macrophage-EV/siHMGB1 to assess the in vivo effect of macrophage-EV/siHMGB1 on AS mice. RAW264.7 cells were subjected to ox-LDL, LPS or macrophage-EV/siHMGB1 for analyzing the in vitro effect of macrophage-EV/siHMGB1 on macrophage pyrophosis and inflammation.

RESULTS

In silico analysis found that HMGB1 was closely related to the development of AS. Macrophage-EV/siHMGB could inhibit the release of HMGB1 from macrophages to outside cells, and the reduced HMGB1 release could inhibit foam cell formation. Besides, macrophage-EV/siHMGB also inhibited the LPS-induced Caspase-11 activation, thus inhibiting macrophage pyroptosis and preventing atherosclerotic plaque formation.

CONCLUSION

Our results proved that macrophage-EV/siHMGB could inhibit foam cell formation and suppress macrophage pyroptosis, finally preventing atherosclerotic plaque formation in AS mice.

Two sides of the same coin: Non-alcoholic fatty liver disease and atherosclerosis

The prevalence of non-alcoholic fatty liver disease (NAFLD) and atherosclerosis remain high, which is primarily due to widespread adoption of a western diet and sedentary lifestyle. NAFLD, together with advanced forms of this disease such as non-alcoholic steatohepatitis (NASH) and cirrhosis, are closely associated with atherosclerotic-cardiovascular disease (ASCVD). In this review, we discussed the association between NAFLD and atherosclerosis and expounded on the common molecular biomarkers underpinning the pathogenesis of both NAFLD and atherosclerosis. Furthermore, we have summarized the mode of function and potential clinical utility of existing drugs in the context of these diseases.

Epigenetic Network in Immunometabolic Disease

Although a large amount of data consistently shows that genes affect immunometabolic characteristics and outcomes, epigenetic mechanisms are also heavily implicated. Epigenetic changes, including DNA methylation, histone modification, and noncoding RNA, determine gene activity by altering the accessibility of chromatin to transcription factors. Various factors influence these alterations, including genetics, lifestyle, and environmental cues. Moreover, acquired epigenetic signals can be transmitted across generations, thus contributing to early disease traits in the offspring. A closer investigation is critical in this aspect as it can help to understand the underlying molecular mechanisms further and gain insights into potential therapeutic targets for preventing and treating diseases arising from immuno-metabolic dysregulation. In this review, the role of chromatin alterations in the transcriptional modulation of genes involved in insulin resistance, systemic inflammation, macrophage polarization, endothelial dysfunction, metabolic cardiomyopathy, and nonalcoholic fatty liver disease (NAFLD), is discussed. An overview of emerging chromatin-modifying drugs and the importance of the individual epigenetic profile for personalized therapeutic approaches in patients with immuno-metabolic disorders is also presented.

EZH2 Promotes Corneal Endothelial Cell Apoptosis by Mediating H3K27me3 and Inhibiting HO-1 Transcription

PURPOSE

This paper aims to explore the molecular mechanism of Enhancer of Zeste Homolog 2 (EZH2)-mediated H3K27me3 in human corneal endothelial cells (HCEC) apoptosis by inhibiting Heme oxygenase-1 (HO-1) transcription to provide a potential target for the treatment of corneal apoptosis.

METHODS

HCECs were cultured in vitro and transfected with si-EZH2, pcDNA3.1-EZH2, pcDNA3.1-HO-1, GSK-J4 (an effective H3K27me3 demethylase inhibitor), and corresponding controls. Western Blot assay was used to detect the levels of EZH2, HO-1, H3K27me3, and apoptosis-related proteins (Bcl-2, Bax, and Cleaved-caspase-3) in HCECs; CCK-8 assay was conducted to detect cell viability and flow cytometry to analyze the apoptosis. HO-1 mRNA levels were detected by RT-qPCR and changes in H3K27me3 levels on the HO-1 promoter were detected by chromatin immunoprecipitation.

RESULTS

HCECs transfected with si-EZH2 showed significantly lower EZH2 mRNA and protein levels, higher HCEC viability, lower apoptosis rates, higher antiapoptotic protein Bcl-2 expression, lower proapoptotic protein (Bax and Cleaved-caspase-3) levels, and significantly higher HO-1 expression. HCECs transfected with pcDNA3.1-EZH2 showed the opposite results. EZH2 repressed HO-1 transcription by mediating H3K27me3. H3K27me27 was enriched in the HO-1 promoter and overexpression of EZH2 increased H3K27me27 levels. Promotion of H3K27me3 partially reversed the mitigating effect of si-EZH2 on HCEC apoptosis. Overexpression of HO-1 partially reversed the apoptosis-promoting effects of EZH2 and H3K27me3 on HCECs.

CONCLUSIONS

EZH2 promotes HCE cell apoptosis by mediating H3K27me3 to inhibit HO-1 transcription.

EZH2 can be used as a therapeutic agent for inhibiting endothelial dysfunction

Enhancer of zeste homolog 2 (EZH2) is a catalytic subunit of polycomb repressor complex 2 and plays important roles in endothelial cell homeostasis. EZH2 functionally methylates lysine 27 of histone H3 and represses gene expression through chromatin compaction. EZH2 mediates the effects of environmental stimuli by regulating endothelial functions, such as angiogenesis, endothelial barrier integrity, inflammatory signaling, and endothelial mesenchymal transition. Numerous studies have been conducted to determine the significance of EZH2 in endothelial function. The aim of this review is to provide a concise summary of the roles EZH2 plays in endothelial function and elucidate its therapeutic potential in cardiovascular diseases.

Role and therapeutic potential of gelsolin in atherosclerosis

Atherosclerosis is the major pathophysiological basis of a variety of cardiovascular diseases and has been recognized as a lipid-driven chronic inflammatory disease. Gelsolin (GSN) is a member of the GSN family. The main function of GSN is to cut and seal actin filaments to regulate the cytoskeleton and participate in a variety of biological functions, such as cell movement, morphological changes, metabolism, apoptosis and phagocytosis. Recently, more and more evidences have demonstrated that GSN is Closely related to atherosclerosis, involving lipid metabolism, inflammation, cell proliferation, migration and thrombosis. This article reviews the role of GSN in atherosclerosis from inflammation, apoptosis, angiogenesis and thrombosis.

Abnormally elevated EZH2-mediated H3K27me3 enhances osteogenesis in aortic valve interstitial cells by inhibiting SOCS3 expression

BACKGROUND AND AIMS

The osteogenic transition of aortic valve interstitial cells (AVICs) plays a critical role for the progression of calcific aortic valve disease (CAVD). Enhancer of zeste homolog 2 (EZH2) is an important methyltransferase for histone H3 Lys27 (H3K27) that has been found to be involved in osteogenesis. Here, we investigated the effect and mechanism of EZH2 in CAVD progression.

METHODS

High throughout mRNA sequencing, qRT-PCR and immunoblot were performed to screen differentially expressed genes in non-CAVD and CAVD aortic valves. To investigate the role of EZH2 and SOCS3 in osteogenesis, AVICs were treated with siRNA, adenovirus and specific inhibitors, then osteogenic markers and mineralized deposits were examined. In vivo, the morphology and function of aortic valves were investigated by HE stain and echocardiography in ApoE^-/- mice fed a long-term western diet (WD).

RESULTS

We discovered that EZH2 was upregulated and SOCS3 was downregulated in calcified aortic valves. In AVICs, inhibition or silencing of EZH2 attenuated the osteogenic responses. On the other hand, demethylases inhibitor (GSK-J4) enhanced osteogenic transition of AVICs. Moreover, SOCS3 knockdown enhanced the expression of osteogenic markers, while SOCS3 overexpression suppressed osteogenesis and calcification. The chromatin immunoprecipitation and restored experiments indicated that EZH2 directly targeted SOCS3 to promote osteogenic responses of AVICs. In vivo, treatment with EZH2 inhibitor through intraperitoneal injection attenuated aortic valve thickening, calcification and dysfunction induced by WD.

CONCLUSIONS

Collectively, we found that EZH2-mediated H3K27me3 enhanced osteogenesis and microcalcification of AVICs via inhibiting SOCS3 expression, which provides potential targets for future therapeutic interventions of CAVD.

MicroRNAs as Biomarkers for Coronary Artery Disease Related to Type 2 Diabetes Mellitus-From Pathogenesis to Potential Clinical Application

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease with still growing incidence among adults and young people worldwide. Patients with T2DM are more susceptible to developing coronary artery disease (CAD) than non-diabetic individuals. The currently used diagnostic methods do not ensure the detection of CAD at an early stage. Thus, extensive research on non-invasive, blood-based biomarkers is necessary to avoid life-threatening events. MicroRNAs (miRNAs) are small, endogenous, non-coding RNAs that are stable in human body fluids and easily detectable. A number of reports have highlighted that the aberrant expression of miRNAs may impair the diversity of signaling pathways underlying the pathophysiology of atherosclerosis, which is a key player linking T2DM with CAD. The preclinical evidence suggests the atheroprotective and atherogenic influence of miRNAs on every step of T2DM-induced atherogenesis, including endothelial dysfunction, endothelial to mesenchymal transition, macrophage activation, vascular smooth muscle cells proliferation/migration, platelet hyperactivity, and calcification. Among the 122 analyzed miRNAs, 14 top miRNAs appear to be the most consistently dysregulated in T2DM and CAD, whereas 10 miRNAs are altered in T2DM, CAD, and T2DM-CAD patients. This up-to-date overview aims to discuss the role of miRNAs in the development of diabetic CAD, emphasizing their potential clinical usefulness as novel, non-invasive biomarkers and therapeutic targets for T2DM individuals with a predisposition to undergo CAD.

HMGB1 promotes Ox-LDL-induced endothelial cell damage by inhibiting PI3K/Akt signaling pathway

BACKGROUND

Atherosclerosis is the pathological basis of cardio-cerebrovascular diseases. Oxidized low-density lipoprotein (ox-LDL) is an important risk factor for atherosclerosis. Ox-LDL leads to endothelial cell (EC) damage and dysfunction through various processes and promotes the occurrence and deterioration of atherosclerosis. High mobility group box-1 (HMGB1) is a protein associated with cellular damage. In the present study, the effect of HMGB1 on ox-LDL-induced EC damage was determined and the underlying mechanism explored.

MATERIALS AND METHODS

Human umbilical vein ECs (HUVECs) were exposed to ox-LDL to induce endothelial damage and changes in HMGB1 expression level were detected using western blotting analysis and reverse transcription-quantitative PCR. To observe the effect of HMGB1 on ox-LDL-induced damage, the HMGB1 expression was downregulated with siRNA, and cell viability, cytotoxicity, and apoptosis rate were assessed. HUVECs were pretreated with LY294002, an inhibitor of the PI3K/Akt pathway, to determine whether the effect of HMGB1 on damage is via the PI3K-Akt pathway.

RESULTS

The results showed that ox-LDL can upregulate HMGB1 expression in HUVECs and downregulation of HMGB1 expression can prevent ox-LDL-induced damage in HUVECs. Furthermore, the effect of HMGB1 on ox-LDL-induced damage could be promoted by inhibiting the PI3K/Akt signaling pathway.

CONCLUSION

The results indicate HMGB1 may be a promising research target to alleviate ox-LDL-induced EC damage.

Genome-wide post-transcriptional regulation of bovine mammary gland response to Streptococcus uberis

MicroRNAs (miRNAs) as post-transcriptionally regulators of gene expression have been shown to be critical regulators to fine-tuning immune responses, besides their criteria for being an ideal biomarker. The regulatory role of miRNAs in responses to most mastitis-causing pathogens is not well understood. Gram-positive Streptococcus uberis (Str. uberis), the leading pathogen in dairy herds, cause both clinical and subclinical infections. In this study, a system biology approach was used to better understand the main post-transcriptional regulatory functions and elements of bovine mammary gland response to Str. uberis infection. Publicly available miRNA-Seq data containing 50 milk samples of the ten dairy cows (five controls and five infected) were retrieved for this current research. Functional enrichment analysis of predicted targets revealed that highly confident responsive miRNAs (4 up- and 19 downregulated) mainly regulate genes involved in the regulation of transcription, apoptotic process, regulation of cell adhesion, and pro-inflammatory signaling pathways. Time series analysis showed that six gene clusters significantly differed in comparisons between Str. uberis-induced samples with controls. Additionally, other bioinformatic analysis, including upstream network analysis, showed essential genes, including TP53 and TGFB1 and some small molecules, including glucose, curcumin, and LPS, commonly regulate most of the downregulated miRNAs. Upregulated miRNAs are commonly controlled by the most important genes, including IL1B, NEAT1, DICER1 enzyme and small molecules including estradiol, tamoxifen, estrogen, LPS, and epigallocatechin. Our study used results of next-generation sequencing to reveal key miRNAs as the main regulator of gene expression responses to a Gram-positive bacterial infection. Furthermore, by gene regulatory network (GRN) analysis, we can introduce the common upregulator transcription factor of these miRNAs. Such milk-based miRNA signature(s) would facilitate risk stratification for large-scale prevention programs and provide an opportunity for early diagnosis and therapeutic intervention.

Lnc-C2orf63-4-1 Confers VSMC Homeostasis and Prevents Aortic Dissection Formation via STAT3 Interaction

Emerging evidence indicates that long non-coding RNAs (lncRNAs) serve as a critical molecular regulator in various cardiovascular diseases. Here, we aimed to identify and functionally characterize lncRNAs as potential mediators in the development of thoracic aortic dissection (TAD). We identified that a novel lncRNA, lnc-C2orf63-4-1, was lowly expressed in aortic samples of TAD patients and angiotensin II (Ang II)-challenged vascular smooth muscle cells (VSMCs), which was correlated with clinically aortic expansion. Besides, overexpression of lnc-C2orf63-4-1 significantly attenuated Ang II-induced apoptosis, phenotypic switching of VSMCs and degradation of extracellular matrix both in vitro and in vivo. A customized transcription factor array identified that signal transducer and activator of transcription 3 (STAT3) functioned as the main downstream effector. Mechanistically, dual-luciferase report analysis and RNA antisense purification (RAP) assay indicated that lnc-C2orf63-4-1 directly decreased the expression of STAT3, which was depend on the reduced stabilization of STAT3 mRNA. Importantly, up-regulation of STAT3 efficiently reversed the protective role of lnc-C2orf63-4-1 against Ang II-mediated vascular remodeling. Therefore, lnc-C2orf63-4-1 negatively regulated the expression of STAT3 and prevented the development of aortic dissection. Our study revealed that lnc-C2orf63-4-1 played a critical role in vascular homeostasis, and its dysfunction exacerbated Ang II-induced pathological vascular remodeling.

Dysfunctional Vascular Endothelium as a Driver of Atherosclerosis: Emerging Insights Into Pathogenesis and Treatment

Atherosclerosis, the chronic accumulation of cholesterol-rich plaque within arteries, is associated with a broad spectrum of cardiovascular diseases including myocardial infarction, aortic aneurysm, peripheral vascular disease, and stroke. Atherosclerotic cardiovascular disease remains a leading cause of mortality in high-income countries and recent years have witnessed a notable increase in prevalence within low- and middle-income regions of the world. Considering this prominent and evolving global burden, there is a need to identify the cellular mechanisms that underlie the pathogenesis of atherosclerosis to discover novel therapeutic targets for preventing or mitigating its clinical sequelae. Despite decades of research, we still do not fully understand the complex cell-cell interactions that drive atherosclerosis, but new investigative approaches are rapidly shedding light on these essential mechanisms. The vascular endothelium resides at the interface of systemic circulation and the underlying vessel wall and plays an essential role in governing pathophysiological processes during atherogenesis. In this review, we present emerging evidence that implicates the activated endothelium as a driver of atherosclerosis by directing site-specificity of plaque formation and by promoting plaque development through intracellular processes, which regulate endothelial cell proliferation and turnover, metabolism, permeability, and plasticity. Moreover, we highlight novel mechanisms of intercellular communication by which endothelial cells modulate the activity of key vascular cell populations involved in atherogenesis, and discuss how endothelial cells contribute to resolution biology - a process that is dysregulated in advanced plaques. Finally, we describe important future directions for preclinical atherosclerosis research, including epigenetic and targeted therapies, to limit the progression of atherosclerosis in at-risk or affected patients.

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.

Oxidized LDL-regulated microRNAs for evaluating vascular endothelial function: molecular mechanisms and potential biomarker roles in atherosclerosis

As a simple monolayer, vascular endothelial cells can respond to physicochemical stimuli. In addition to promoting the formation of foam cells, oxidized low-density lipoprotein (ox-LDL) contributes to the atherosclerotic process through different mechanisms, including endothelial cell dysfunction. As conserved noncoding RNAs, microRNAs (miRNAs) naturally lie in different genomic positions and post-transcriptionally regulate the expression of many genes. They participate in integrated networks formed under stress to maintain cellular homeostasis, vascular inflammation, and metabolism. These small RNAs constitute therapeutic targets in different diseases, including atherosclerosis, and their role as biomarkers is crucial given their detectability even years before the emergence of diseases. This review was performed to investigate the role of ox-LDL-regulated miRNAs in atherosclerosis, their molecular mechanisms, and their application as biomarkers of vascular endothelial cell dysfunction.

microRNA-193-3p attenuates myocardial injury of mice with sepsis via STAT3/HMGB1 axis

Objective

Little is known regarding the functional role of microRNA-193-3p (miR-193-3p) in sepsis. Hence, the aim of the present study was to investigate the effect of miR-193-3p on myocardial injury in mice with sepsis and its mechanism through the regulation of signal transducers and activators of transcription 3 (STAT3).

Methods

The mice model of sepsis was established by cecal ligation and puncture (CLP), septic mice were injected with miR-193-3p agomir, miR-193-3p antagomir or siRNA-STAT3. The expression of miR-193-3p, STAT3 and HMGB1 in the myocardial tissue of septic mice were detected. Cardiac ultrasound, hemodynamics, myocardial injury markers, inflammatory factors and cardiomyocyte apoptosis in septic mice were measured.

Results

MiR-193-3p expression was reduced while STAT3 expression was increased in septic mice. Down-regulated STAT3 or up-regulated miR-193-3p improved cardiac function, attenuated myocardial injury, inflammation and cardiomyocyte apoptosis in septic mice. Knockdown STAT3 reversed the role of inhibited miR-193-3p for mice with sepsis. miR-193-3p targeted STAT3, thereby inhibiting HMGB1 expression.

Conclusion

This study provides evidence that miR-193-3p targets STAT3 expression to reduce HMGB1 expression, thereby reducing septic myocardial damage. MiR-193-3p might be a potential candidate marker and therapeutic target for sepsis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03022-x.

Inflammatory Mechanisms Contributing to Endothelial Dysfunction

Maintenance of endothelial cell integrity is an important component of human health and disease since the endothelium can perform various functions including regulation of vascular tone, control of hemostasis and thrombosis, cellular adhesion, smooth muscle cell proliferation, and vascular inflammation. Endothelial dysfunction is encompassed by complex pathophysiology that is based on endothelial nitric oxide synthase uncoupling and endothelial activation following stimulation from various inflammatory mediators (molecular patterns, oxidized lipoproteins, cytokines). The downstream signaling via nuclear factor-κB leads to overexpression of adhesion molecules, selectins, and chemokines that facilitate leukocyte adhesion, rolling, and transmigration to the subendothelial space. Moreover, oscillatory shear stress leads to pro-inflammatory endothelial activation with increased monocyte adhesion and endothelial cell apoptosis, an effect that is dependent on multiple pathways and flow-sensitive microRNA regulation. Moreover, the role of neutrophil extracellular traps and NLRP3 inflammasome as inflammatory mechanisms contributing to endothelial dysfunction has recently been unveiled and is under further investigation. Consequently, and following their activation, injured endothelial cells release inflammatory mediators and enter a pro-thrombotic state through activation of coagulation pathways, downregulation of thrombomodulin, and an increase in platelet adhesion and aggregation owing to the action of von-Willebrand factor, ultimately promoting atherosclerosis progression.

Endothelial Dysfunction in Atherosclerotic Cardiovascular Diseases and Beyond: From Mechanism to Pharmacotherapies

The endothelium, a cellular monolayer lining the blood vessel wall, plays a critical role in maintaining multiorgan health and homeostasis. Endothelial functions in health include dynamic maintenance of vascular tone, angiogenesis, hemostasis, and the provision of an antioxidant, anti-inflammatory, and antithrombotic interface. Dysfunction of the vascular endothelium presents with impaired endothelium-dependent vasodilation, heightened oxidative stress, chronic inflammation, leukocyte adhesion and hyperpermeability, and endothelial cell senescence. Recent studies have implicated altered endothelial cell metabolism and endothelial-to-mesenchymal transition as new features of endothelial dysfunction. Endothelial dysfunction is regarded as a hallmark of many diverse human panvascular diseases, including atherosclerosis, hypertension, and diabetes. Endothelial dysfunction has also been implicated in severe coronavirus disease 2019. Many clinically used pharmacotherapies, ranging from traditional lipid-lowering drugs, antihypertensive drugs, and antidiabetic drugs to proprotein convertase subtilisin/kexin type 9 inhibitors and interleukin 1β monoclonal antibodies, counter endothelial dysfunction as part of their clinical benefits. The regulation of endothelial dysfunction by noncoding RNAs has provided novel insights into these newly described regulators of endothelial dysfunction, thus yielding potential new therapeutic approaches. Altogether, a better understanding of the versatile (dys)functions of endothelial cells will not only deepen our comprehension of human diseases but also accelerate effective therapeutic drug discovery. In this review, we provide a timely overview of the multiple layers of endothelial function, describe the consequences and mechanisms of endothelial dysfunction, and identify pathways to effective targeted therapies. SIGNIFICANCE STATEMENT: The endothelium was initially considered to be a semipermeable biomechanical barrier and gatekeeper of vascular health. In recent decades, a deepened understanding of the biological functions of the endothelium has led to its recognition as a ubiquitous tissue regulating vascular tone, cell behavior, innate immunity, cell-cell interactions, and cell metabolism in the vessel wall. Endothelial dysfunction is the hallmark of cardiovascular, metabolic, and emerging infectious diseases. Pharmacotherapies targeting endothelial dysfunction have potential for treatment of cardiovascular and many other diseases.

EZH2 as an epigenetic regulator of cardiovascular development and diseases

ABSTRACT

Enhancer of zeste homolog 2(EZH2) is an enzymatic subunit of polycomb repressive complex 2 (PRC2) and is responsible for catalyzing mono-, di-, and trimethylation of histone H3 at lysine-27(H3K27me1/2/3). Many noncoding RNAs or signaling pathways are involved in EZH2 functional alterations. This new epigenetic regulation of target genes is able to silence downstream gene expression and modify physiological and pathological processes in heart development, cardiomyocyte regeneration and cardiovascular diseases such as hypertrophy, ischemic heart diseases, atherosclerosis and cardiac fibrosis. Targeting the function of EZH2 could be a potential therapeutic approach for cardiovascular diseases.

Electroacupuncture promotes the recovery of rats with spinal cord injury by suppressing the Notch signaling pathway via the H19/EZH2 axis

Background

Spinal cord injury (SCI) is a life-changing event with an extremely poor prognosis. In our preliminary studies, electroacupuncture (EA) was found to promote the repair of SCI, which was closely related to the Notch signaling pathway. Therefore, in the present study, we hypothesized that EA protects against SCI by inhibiting the Notch signaling pathway and sought to investigate the underlying molecular mechanisms.

Methods

Rat and cell models of SCI were established. The expression of long non-coding RNA H19 was measured by real-time quantitative polymerase chain reaction. The expression levels of EZH2, Notch1, Notch3, Notch4, Hes1, and PS1 protein were measured by western blot. Cell apoptosis and viability were analyzed using flow cytometry and Cell Counting Kit-8 assays, respectively. The expressions of glial fibrillary acidic protein (GFAP) and nestin were detected by immunofluorescence staining.

Results

The expressions of H19, EZH2, and GFAP were significantly increased after SCI but were inhibited by EA; in contrast, nestin expression was significantly decreased by SCI but was restored by EA. Moreover, oxygen-glucose deprivation (OGD) treatment elevated the expression of H19, EZH2, and Notch-related factors as well as apoptosis in PC-12 cells, while suppressing cell viability. Suppressing H19 alleviated the effects of OGD on cell viability and apoptosis, and inhibited the expression of EZH2 and Notch-related factors expression; these effects were reversed by EZH2 overexpression. Finally, EA promoted the recovery of SCI rats and neural stem cell (NSC) proliferation by inhibiting the Notch signaling pathway, which was reversed by H19 overexpression.

Conclusions

Our results demonstrated that EA promotes the recovery of SCI rats and increases the proliferation and differentiation of NSCs by suppressing the Notch signaling pathway via modulating the H19/EZH2 axis.

Toward the Effective Bioengineering of a Pathological Tissue for Cardiovascular Disease Modeling: Old Strategies and New Frontiers for Prevention, Diagnosis, and Therapy

Cardiovascular diseases (CVDs) still represent the primary cause of mortality worldwide. Preclinical modeling by recapitulating human pathophysiology is fundamental to advance the comprehension of these diseases and propose effective strategies for their prevention, diagnosis, and treatment. In silico, in vivo, and in vitro models have been applied to dissect many cardiovascular pathologies. Computational and bioinformatic simulations allow developing algorithmic disease models considering all known variables and severity degrees of disease. In vivo studies based on small or large animals have a long tradition and largely contribute to the current treatment and management of CVDs. In vitro investigation with two-dimensional cell culture demonstrates its suitability to analyze the behavior of single, diseased cellular types. The introduction of induced pluripotent stem cell technology and the application of bioengineering principles raised the bar toward in vitro three-dimensional modeling by enabling the development of pathological tissue equivalents. This review article intends to describe the advantages and disadvantages of past and present modeling approaches applied to provide insights on some of the most relevant congenital and acquired CVDs, such as rhythm disturbances, bicuspid aortic valve, cardiac infections and autoimmunity, cardiovascular fibrosis, atherosclerosis, and calcific aortic valve stenosis.

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.

Enhancer of zeste homolog 2 participates in the process of atherosclerosis by modulating microRNA-139-5p methylation and signal transducer and activator of transcription 1 expression

Atherosclerosis (AS) is the main cause of coronary heart disease, in which enhancer of zeste homolog 2 (EZH2) has been implied to participate in this process. Thus, this work proposed to explore the effect of EZH2 on AS from microRNA-139-5p (miR-139-5p)/signal transducer and activator of transcription 1 (STAT1) axis. EZH2, miR-139-5p, and STAT1 expression in arterial tissues of AS patients were detected. Human arterial smooth muscle cells (HASMCs) induced with oxidized low-density lipoprotein (ox-LDL) and the mice fed with high fat diet were treated with silenced EZH2 or upregulated miR-139-5p to explore their roles in proliferation and apoptosis of HASMCs, together with inflammation response and oxidative stress of mice. Chromatin immunoprecipitation experiment was applied to verify the regulatory effect of EZH2 on miR-139-5p through methylation of H3K27me3. The targeting relationship between miR-139-5p and STAT1 was verified by online website and luciferase activity assay. Reduced miR-139-5p and overexpressed EHZ2 and STAT1 were found in AS. Silenced EZH2 or elevated miR-139-5p decreased the production of cholesterol and inhibited inflammation reaction in serum of mice with AS. Silenced EZH2 or elevated miR-139-5p facilitated proliferation and restrained apoptosis of ox-LDL-treated HASMCs, and restrained oxidative stress and cell apoptosis in arterial tissues of AS mice. EZH2 regulated miR-139-5p through H3K27me3, and miR-139-5p targeted STAT1. miR-139-5p silencing antagonized the effects of EZH2 down-regulation on AS. This study manifests that down-regulated EZH2 or elevated miR-139-5p inhibits ox-LDL-induced HASMCs apoptosis, plaque formation, and inflammatory response in AS mice, which may be related to down-regulated STAT1.