MicroRNAs: important modulators of oxLDL-mediated signaling in atherosclerosis

Tanshinone IIA: a Chinese herbal ingredient for the treatment of atherosclerosis

Tanshinone IIA (Tan IIA) is a fat-soluble compound extracted from Salvia miltiorrhiza, which has a protective effect against atherosclerosis (AS). Tan IIA can inhibit oxidative stress and inflammatory damage of vascular endothelial cells (VECs) and improve endothelial cell dysfunction. Tan IIA also has a good protective effect on vascular smooth muscle cells (VSMCs). It can reduce vascular stenosis by inhibiting the proliferation and migration of vascular smooth muscle cells (VSMCs), and improve the stability of the fibrous cap of atherosclerotic plaque by inhibiting apoptosis and inflammation of VSMCs. In addition, Tan IIA inhibits the inflammatory response of macrophages and the formation of foam cells in atherosclerotic plaques. In summary, Tan IIA improves AS through a complex pathway. We propose to further study the specific molecular targets of Tan IIA using systems biology methods, so as to fundamentally elucidate the mechanism of Tan IIA. It is worth mentioning that there is a lack of high-quality evidence-based medical data on Tan IIA treatment of AS. We recommend that a randomized controlled clinical trial be conducted to evaluate the exact efficacy of Tan IIA in improving AS. Finally, sodium tanshinone IIA sulfonate (STS) can cause adverse drug reactions in some patients, which needs our attention.

Inclisiran inhibits oxidized low-density lipoprotein-induced foam cell formation in Raw264.7 macrophages via activating the PPARγ pathway

Proprotein convertase subtilisin kexin type 9 (PCSK9) is a well-known proprotein convertase that influences foam cell formation and modulates atherosclerosis. Inclisiran is a novel chemosynthetic small interfering RNA that inhibits PCSK9 synthesis. This study aimed to explore the effect of inclisiran on oxidized low-density lipoprotein (ox-LDL)-induced foam cell formation in Raw264.7 macrophages and to investigate the underlying mechanisms. Raw264.7 cells were treated with ox-LDL to induce the formation of macrophage-derived foam cells. Oil Red O staining and high-performance liquid chromatography were performed to detect lipid accumulation and cholesterol levels. Dil-ox-LDL uptake assay, CCK-8, RT-qPCR, and Western blotting analysis were performed to examine ox-LDL uptake, cell viability, and expression of scavenger receptor-related factors. Inclisiran reduced lipid accumulation in ox-LDL-treated macrophages in a dose-dependent manner. Inclisiran significantly inhibited the levels of total cholesterol, free cholesterol, and cholesterol ester in the supernatant of Raw264.7 cells. Inclisiran reduced ox-LDL uptake and increased Raw264.7 cell viability. Meanwhile, inclisiran downregulated the expression of SR-A, LOX-1, and CD36 and upregulated SR-BI, ApoE, and ABCA1. Furthermore, inclisiran increased PPARγ activity and decreased NF-κB activity. An inhibitor of PPARγ (T0070907) reversed the beneficial effects of inclisiran on ox-LDL uptake, NF-κB inactivation, and cytokine expression. In conclusion, these data suggested that inclisiran inhibited the formation of macrophage-derived foam cells by activating the PPARγ pathway.HighlightsInclisiran reduces lipid accumulation in Raw264.7 cells;Inclisiran reduces ox-LDL uptake and increases Raw264.7 cell viability;Inclisiran inhibits foam cell formation by activating the PPARγ pathway.

Role and Mechanism of mir-5189-3p in Deep Vein Thrombosis of Lower Extremities

BACKGROUND

This study is to investigate the role and mechanism of mir-5189-3p in deep vein thrombosis (DVT) in lower extremity.

METHODS

The blood samples were collected from Kazakh patients with DVT in lower extremity and were subjected to microRNA sequencing. Bioinformatics were used to identify mir-5189-3p and its target genes. Dual luciferase reporter assay was used to determine the regulatory effect of mir-5189-3p on JAG1. SD rats were randomly divided into normal control, DVT model, hsa-miR-5189-3p mimics and hsa-miR-5189-3p negative control groups. HE staining was used to observe the pathological changes. TUNEL method was used to observe apoptosis. Western blot was used to detect Bax and Bcl-2 protein expression. Real-time quantitative PCR was used to detect JAG1, Notch1 and Hes1 mRNA.

RESULTS

The target of Has-miR-5189-3p was JAG1. Co-transfection of miR-5189-3p mimics and pmirGLO/JAG1 wild-type plasmid induced significantly decreased luciferase activity. In hsa-miR-5189-3p mimics and hsa-miR-5189-3p negative control groups, there were more nucleated cells in the thrombus tissues, and the organization degree obviously increased. Signs of blood flow recanalization were observed. The apoptosis of hsa-miR-5189-3p mimics and hsa-miR-5189-3p negative control groups was lower than that in DVT model group. Furthermore, mir-5189-3p mimics significantly increased the mRNA levels of JAG1, Notch1 and Hes1. Additionally, mir-5189-3p mimics significantly increased Bcl-2 while decreased Bax protein.

CONCLUSIONS

mir-5189-3p could inhibit apoptosis and promote thrombus organization in DVT possibly via Notch signaling pathway. Mir-5189-3p can be used as a potential target for DVT treatment.

MiR-296-5p ameliorates deep venous thrombosis by inactivating S100A4

Deep venous thrombosis is one of the most common venous thromboembolic diseases and has a low cure rate and a high postoperative recurrence rate. Furthermore, emerging evidence indicates that microRNAs are involved in deep venous thrombosis. miR-296-5p is an important microRNA that plays a critical role in various cellular functions, and S100A4 is closely related to vascular function. miR-296-5p is downregulated in deep venous thrombosis patients, and its predicted target S100A4 is upregulated in deep venous thrombosis patients. Therefore, it was hypothesized that miR-296-5p may play a vital role in the development of deep venous thrombosis by targeting S100A4. An Ox-LDL-stimulated HUVEC and deep venous thrombosis mouse model was employed to detect the biological functions of miR-296-5p and S100A4. Dual luciferase reporter assays and pull-down assays were used to authenticate the interaction between miR-296-5p and S100A4. ELISA and Western blotting were employed to detect the protein levels of thrombosis-related factors and the endothelial-to-mesenchymal transition (EndMT)-related factors. The miR-296-5p levels were reduced, while the S100A4 levels were enhanced in deep venous thrombosis patients, and the miR-296-5p levels were negatively correlated with the S100A4 levels in deep venous thrombosis patients. miR-296-5p suppressed S100A4 expression by targeting the 3' UTR of S100A4. MiR-296-5p knockdown accelerated ox-LDL-induced HUVEC apoptosis, oxidative stress, thrombosis-related factor expression, and EndMT, while S100A4 knockdown antagonized these effects in ox-LDL-induced HUVECs. S100A4 knockdown reversed the effect induced by miR-296-5p knockdown. Moreover, the in vivo studies revealed that miR-296-5p knockdown in deep venous thrombosis mice exacerbated deep venous thrombosis formation, whereas S100A4 knockdown had the opposite effect. These results indicate that elevated miR-296-5p inhibits deep venous thrombosis formation by inhibiting S100A4 expression. Both miR-296-5p and S100A4 may be potential diagnostic markers and therapeutic targets for deep venous thrombosis.

Foxc2 Alleviates Ox-LDL-Induced Lipid Accumulation, Inflammation, and Apoptosis of Macrophage via Regulating the Expression of Angptl2

The present study aimed to investigate the role of Forkhead box protein C2 (Foxc2) in oxidized low-density lipoprotein (ox-LDL)-induced macrophages and identify the potential mechanisms. RAW264.7 cells, the murine macrophage cell line, were stimulated by ox-LDL, and cell proliferation was examined. The levels of inflammation- and oxidative stress-related markers were detected using kits after induction with ox-LDL. Subsequently, the expression of Foxc2 was measured using Western blotting. After transfection with Foxc2 pcDNA3.1, intracellular lipid droplets were examined using oil red O staining. The levels of total cholesterol (TC), free cholesterol (FC), inflammatory cytokines, and oxidative stress markers were determined. Moreover, apoptosis of RAW264.7 cells was detected using flow cytometry, and apoptosis-related proteins were measured using Western blotting. Angiopoietin-like protein 2 (Angptl2) was predicted as a target gene of Foxc2. Therefore, the expression of Angptl2 was examined after Foxc2 overexpression in ox-LDL-induced RAW264.7 cells. Then, the changes of intracellular lipid droplets, TC, FC, inflammatory cytokines, oxidative stress factors, and cell apoptosis were detected after Angptl2 overexpression or co-transfection with Foxc2 and Angptl2 pcDNA3.1. The results revealed that ox-LDL induction inhibited proliferation of RAW264.7 cells and promoted the release of inflammatory factors. Importantly, the expression of Foxc2 was obviously decreased after stimulation by ox-LDL. Foxc2 overexpression suppressed lipid accumulation, TC, FC levels, inflammation, oxidative stress, and apoptosis induced by ox-LDL, whereas these inhibitory effects were relieved after co-transfection with Angptl2 pcDNA3.1. These findings demonstrated that Foxc2 can alleviate ox-LDL-induced lipid accumulation, inflammation, and apoptosis of macrophage via regulating the expression of Angptl2.

IL (Interleukin)-6 Contributes to Deep Vein Thrombosis and Is Negatively Regulated by miR-338-5p

Supplemental Digital Content is available in the text.

Objective:

Deep venous thrombosis (DVT), one of the most common venous thromboembolic disorders, is closely linked with pulmonary embolism and post-thrombotic syndrome, both of which have a high mortality. However, the factors that trigger DVT formation are still largely unknown. Elevated expression of IL (interleukin)-6—an important inflammatory cytokine—has been linked with DVT formation. However, the molecular mechanisms leading to the elevated IL-6 in DVT remain unclear. Here, we proposed that epigenetic modification of IL-6 at the post-transcriptional level may be a crucial trigger for IL-6 upregulation in DVT.

Approach and Results:

To explore the association between microRNAs and IL-6 in DVT, we performed microRNA microarray analysis and experiments both in vitro and in vivo. Microarray and quantitative real-time polymerase chain reaction results showed that IL-6 expression was increased while miR-338-5p level was decreased substantially in peripheral blood mononuclear cells of patients with DVT, and there was significant negative correlation between miR-338-5p and IL-6. Experiments in vitro showed that overexpressed miR-338-5p reduced IL-6 expression, while miR-338-5p knockdown increased IL-6 expression. Moreover, our in vivo study found that mice with anti–IL-6 antibody or agomiR-338-5p delivery resulted in decreased IL-6 expression and alleviated DVT formation, whereas antagomiR-338-5p acted inversely. Most of miR-338-5p was found located in cytoplasm by fluorescence in situ hybridization. Dual-luciferase reporter assay identified direct binding between miR-338-5p and IL-6.

Conclusions:

Our results suggest that decreased miR-338-5p promotes DVT formation by increasing IL-6 expression.

Regulatory Factor X1 Downregulation Contributes to Monocyte Chemoattractant Protein-1 Overexpression in CD14+ Monocytes via Epigenetic Mechanisms in Coronary Heart Disease

Monocyte chemoattractant protein 1 (MCP1) affects the chemotaxis of monocytes and is a key chemokine closely related to the development of atherosclerosis (AS). Compared with healthy controls, coronary heart disease (CAD) patients show significantly upregulated plasma concentrations and mRNA expression of MCP1 in CD14+ monocytes. However, the specific regulatory mechanism of MCP1 overexpression in AS is still unclear. Our previous research indicated that there was no significant difference in the H3K4 and H3K27 tri-methylation of the MCP1 promoter in CD14+ monocytes from CAD versus non-CAD patients, but the H3 and H4 acetylation of the MCP1 promoter was increased in CD14+ monocytes from CAD patients. We further found that the H3K9 tri-methylation of the MCP1 promoter in CD14+ monocytes from CAD patients was decreased, but the DNA methylation levels did not differ markedly from those in non-CAD patients. Our previous work showed that the level of regulatory factor X1 (RFX1) was markedly reduced in CD14+ monocytes from CAD patients and played an important role in the progression of AS by regulating epigenetic modification. In this study, we investigated whether RFX1 and epigenetic modifications mediated by RFX1 contribute to the overexpression of MCP1 in activated monocytes in CAD patients. We found that the enrichment of RFX1, histone deacetylase 1 (HDAC1), and suppressor of variegation 3–9 homolog 1 (SUV39H1) in the MCP1 gene promoter region were decreased in CD14+ monocytes from CAD patients and in healthy CD14+ monocytes treated with low-density lipoprotein (LDL). Chromatin immunoprecipitation (ChIP) assays identified MCP1 as a target gene of RFX1. Overexpression of RFX1 increased the recruitments of HDAC1 and SUV39H1 and inhibited the expression of MCP1 in CD14+ monocytes. In contrast, knockdown of RFX1 in CD14+ monocytes reduced the recruitments of HDAC1 and SUV39H1 in the MCP1 promoter region, thereby facilitating H3 and H4 acetylation and H3K9 tri-methylation in this region. In conclusion, our results indicated that RFX1 expression deficiency in CD14+ monocytes from CAD patients contributed to MCP1 overexpression via a deficiency of recruitments of HDAC1 and SUV39H1 in the MCP1 promoter, which highlighted the vital role of RFX1 in the pathogenesis of CAD.

TIPE2 suppresses atherosclerosis by exerting a protective effect on macrophages via the inhibition of the Akt signaling pathway

Macrophage apoptosis and inflammation serve pivotal roles in the occurrence of atherosclerosis. However, the detailed underlying mechanism of macrophage action during atherosclerosis is poorly understood. Tumor necrosis factor-α-induced protein 8-like 2 (TIPE2) is a well-known negative regulator of the immune response. The current study assessed the association between TIPE2 and apoptosis-associated molecules in macrophages during atherosclerosis, as well as the role of TIPE2 in macrophage inflammation. RAW264.7 macrophages were subsequently transfected with a TIPE2 expression plasmid. Following oxidized low-density lipoprotein (oxLDL) induction (100 µg/m1) for 48 h, macrophage apoptosis was assessed via Annexin V/propidium iodide dual staining. The apoptosis-associated factors and Akt signaling pathway-associated factors were also evaluated via western blot analysis. The expression of inflammatory factors was determined via a reverse transcription-quantitative polymerase chain reaction assay and western blotting. Furthermore, a transwell assay was performed to test cell invasion ability. NF-κB phosphorylation and nuclear translocation were also assessed via western blotting. The results demonstrated that TIPE2 overexpression may promote oxLDL-induced RAW264.7 macrophage apoptosis by inhibiting the protein kinase B (Akt) signaling pathway. Furthermore, it was demonstrated that TIPE2 significantly reduced oxLDL-induced tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and monocyte chemoattractant protein 1 expression (MCP-1), and increased IL-10 expression by suppressing NF-κB phosphorylation and nuclear translocation in RAW264.7 macrophages. These results indicated that TIPE2 serves a protective role in oxLDL-induced RAW264.7 macrophages, and its mechanism may partly be exerted via the inhibition of the PI3K/Akt signaling pathway and the reduction of the macrophage inflammatory response achieved via the suppression of NF-κB signal activation.

Circulating low density lipoprotein (LDL)

Low-density lipoprotein (LDL) particles are known as atherogenic agents in coronary artery diseases. They modify to other electronegative forms and may be the subject for improvement of inflammatory events in vessel subendothelial spaces. The circulating LDL value is associated with the plasma PCSK-9 level. They internalize into macrophages using the lysosomal receptor-mediated pathways. LDL uptake is related to the membrane scavenger receptors, modifications of lipid and protein components of LDL particles, vesicular maturation and lipid stores of cells. Furthermore, LDL vesicular trafficking is involved with the function of some proteins such as Rab and Lamp families. These proteins also help in the transportation of free cholesterol from lysosome into the cytosol. The aggregation of lipids in the cytosol is a starting point for the formation of foam cells so that they may participate in the primary core of atherosclerosis plaques. The effects of macrophage subclasses are different in the formation and remodeling of plaques. This review is focused on the cellular and molecular events involved in cholesterol homeostasis.

Nuclear PTEN enhances the maturation of a microRNA regulon to limit MyD88-dependent susceptibility to sepsis

Sepsis-induced organ damage is caused by systemic inflammatory response syndrome (SIRS), which results in substantial comorbidities. Therefore, it is of medical importance to identify molecular brakes that can be exploited to dampen inflammation and prevent the development of SIRS. We investigated the role of phosphatase and tensin homolog (PTEN) in suppressing SIRS, increasing microbial clearance, and preventing lung damage. Septic patients and mice with sepsis exhibited increased PTEN expression in leukocytes. Myeloid-specific Pten deletion in an animal model of sepsis increased bacterial loads and cytokine production, which depended on enhanced myeloid differentiation primary response gene 88 (MyD88) abundance and resulted in mortality. PTEN-mediated induction of the microRNAs (miRNAs) miR125b and miR203b reduced the abundance of MyD88. Loss- and gain-of-function assays demonstrated that PTEN induced miRNA production by associating with and facilitating the nuclear localization of Drosha-Dgcr8, part of the miRNA-processing complex. Reconstitution of PTEN-deficient mouse embryonic fibroblasts with a mutant form of PTEN that does not localize to the nucleus resulted in retention of Drosha-Dgcr8 in the cytoplasm and impaired production of mature miRNAs. Thus, we identified a regulatory pathway involving nuclear PTEN-mediated miRNA generation that limits the production of MyD88 and thereby limits sepsis-associated mortality.

Dual signaling evoked by oxidized LDLs in vascular cells

The oxidative theory of atherosclerosis relies on the modification of low density lipoproteins (LDLs) in the vascular wall by reactive oxygen species. Modified LDLs, such as oxidized LDLs, are thought to participate in the formation of early atherosclerotic lesions (accumulation of foam cells and fatty streaks), whereas their role in advanced lesions and atherothrombotic events is more debated, because antioxidant supplementation failed to prevent coronary disease events and mortality in intervention randomized trials. As oxidized LDLs and oxidized lipids are present in atherosclerotic lesions and are able to trigger cell signaling on cultured vascular cells and macrophages, it has been proposed that they could play a role in atherogenesis and atherosclerotic vascular remodeling. Oxidized LDLs exhibit dual biological effects, which are dependent on extent of lipid peroxidation, nature of oxidized lipids (oxidized phospholipids, oxysterols, malondialdehyde, α,β-unsaturated hydroxyalkenals), concentration of oxidized LDLs and uptake by scavenger receptors (e.g. CD36, LOX-1, SRA) that signal through different transduction pathways. Moderate concentrations of mildly oxidized LDLs are proinflammatory and trigger cell migration and proliferation, whereas higher concentrations induce cell growth arrest and apoptosis. The balance between survival and apoptotic responses evoked by oxidized LDLs depends on cellular systems that regulate the cell fate, such as ceramide/sphingosine-1-phosphate rheostat, endoplasmic reticulum stress, autophagy and expression of pro/antiapoptotic proteins. In vivo, the intimal concentration of oxidized LDLs depends on the influx (hypercholesterolemia, endothelial permeability), residence time and lipid composition of LDLs, oxidative stress intensity, induction of defense mechanisms (antioxidant systems, heat shock proteins). As a consequence, the local cellular responses to oxidized LDLs may stimulate inflammatory or anti-inflammatory pathways, angiogenic or antiangiogenic responses, survival or apoptosis, thereby contributing to plaque growth, instability, complication (intraplaque hemorrhage, proteolysis, calcification, apoptosis) and rupture. Finally, these dual properties suggest that oxLDLs could be implicated at each step of atherosclerosis development, from early fatty streaks to advanced lesions, depending on the nature and concentration of their oxidized lipid content.

Myeloperoxidase-Oxidized LDLs Enhance an Anti-Inflammatory M2 and Antioxidant Phenotype in Murine Macrophages

Macrophages and oxidized LDLs play a key role in atherogenesis but their heterogeneity has been neglected up to now. Macrophages are prone to polarization and subsets of polarized macrophages have been described in atheromas. LDLs can be oxidized not only chemically by copper (Ox-LDLs) but also enzymatically by myeloperoxidase (MpOx-LDLs) resulting in oxidized LDLs poor in lipid peroxides. The effects of physiologically relevant myeloperoxidase-oxidized LDLs on macrophage polarization or on polarized macrophages remain largely unknown. In this study, the effects of LDLs on macrophage polarization were investigated by monitoring the expression of M1 and M2 genes following stimulation with native LDLs, Ox-LDLs, or MpOx-LDLs in RAW 264.7 cells. Except for MRC1, which is induced only by Ox-LDLs, MpOx-LDLs induced an overexpression of most of the selected marker genes at the mRNA level. MpOx-LDLs also modulate marker gene expression in polarized macrophages favoring notably anti-inflammatory Arg1 expression in M2 cells and also in the other phenotypes. Noteworthy, MpOx-LDLs were the most efficient to accumulate lipids intracellularly in (un)polarized macrophages whatever the phenotype. These data were largely confirmed in murine bone marrow-derived macrophages. Our data suggest that MpOx-LDLs were the most efficient to accumulate within cells and to enhance an anti-inflammatory and antioxidant phenotype in M2 cells and also in the other macrophage phenotypes.

Oxidized Low-density Lipoprotein (ox-LDL) Cholesterol Induces the Expression of miRNA-223 and L-type Calcium Channel Protein in Atrial Fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia causing high morbidity and mortality. While changing of the cellular calcium homeostasis plays a critical role in AF, the L-type calcium channel α1c protein has suggested as an important regulator of reentrant spiral dynamics and is a major component of AF-related electrical remodeling. Our computational modeling predicted that miRNA-223 may regulate the CACNA1C gene which encodes the cardiac L-type calcium channel α1c subunit. We found that oxidized low-density lipoprotein (ox-LDL) cholesterol significantly up-regulates both the expression of miRNA-223 and L-type calcium channel protein. In contrast, knockdown of miRNA-223 reduced L-type calcium channel protein expression, while genetic knockdown of endogenous miRNA-223 dampened AF vulnerability. Transfection of miRNA-223 by adenovirus-mediated expression enhanced L-type calcium currents and promoted AF in mice while co-injection of a CACNA1C-specific miR-mimic counteracted the effect. Taken together, ox-LDL, as a known factor in AF-associated remodeling, positively regulates miRNA-223 transcription and L-type calcium channel protein expression. Our results implicate a new molecular mechanism for AF in which miRNA-223 can be used as an biomarker of AF rheumatic heart disease.

Clinical Significance of Determining Plasma MicroRNA33b in Type 2 Diabetic Patients with Dyslipidemia

Aim: Sterol regulatory element-binding protein (SREBP)-1c is the dominant liver insulin-stimulated isoform and strongly correlates with diabetic dyslipidemia characterized by hyperinsulinemia [i.e., high-density lipoprotein cholesterol (HDL-C) levels and hypertriglyceridemia]. MicroRNA (miRNA) 33b is harbored in the intron of SREBP-1c and represses ATP-binding cassette, sub-family A, and member 1 (ABCA1) expression, essential for HDL formation. We measured plasma miRNA33b levels as possible biomarkers for diabetic dyslipidemia in patients with type 2 diabetes mellitus (T2DM) showing insulin resistance.

Methods: The participants included 50 patients with T2DM (M/F 31/19) enrolled in an educational program for controlling blood glucose levels at Hirosaki University Hospital. HbA1c, fasting plasma glucose, insulin, and lipid levels were determined. Plasma miRNA33b, miRNA33a and miRNA148a were quantified using a TaqMan^® MicroRNA Assay, and values were corrected with reference to miRNA16.

Results: Mean BMI of participants were 28.2 ± 6.6 (kg/m²) and the Homeostasis Model Assessment of Insulin Resistance was 4.3 ± 2.7. Patients' laboratory findings indicated diabetic dyslipidemia with insulin resistance. Plasma miRNA33b/16 levels revealed a positive correlation with plasma insulin level (r = 0.326, P = 0.021), serum C-peptide (r = 0.280, P = 0.049), and triglyceride (r = 0.351, P = 0.012), but no association with HDL-C (r = −0.210, P = 0.143). The blood level of miRNA33a was approximately 1/150th of that of miRNA33b and was not correlated with the above parameters.

Conclusion: We postulated that plasma miRNA33b may be useful as a new metabolic biomarker of dyslipidemia in patients with T2DM as well as metabolic syndrome via an insulin/SREBP-1c/miRNA33b/ABCA1 pathway.

Nutrigenomics, the Microbiome, and Gene-Environment Interactions: New Directions in Cardiovascular Disease Research, Prevention, and Treatment: A Scientific Statement From the American Heart Association

Cardiometabolic diseases are the leading cause of death worldwide and are strongly linked to both genetic and nutritional factors. The field of nutrigenomics encompasses multiple approaches aimed at understanding the effects of diet on health or disease development, including nutrigenetic studies investigating the relationship between genetic variants and diet in modulating cardiometabolic risk, as well as the effects of dietary components on multiple "omic" measures, including transcriptomics, metabolomics, proteomics, lipidomics, epigenetic modifications, and the microbiome. Here, we describe the current state of the field of nutrigenomics with respect to cardiometabolic disease research and outline a direction for the integration of multiple omics techniques in future nutrigenomic studies aimed at understanding mechanisms and developing new therapeutic options for cardiometabolic disease treatment and prevention.

Epigenetic associations in relation to cardiovascular prevention and therapeutics

Cardiovascular diseases (CVD) increasingly burden societies with vast financial and health care problems. Therefore, the importance of improving preventive and therapeutic measures against cardiovascular diseases is continually growing. To accomplish such improvements, research must focus particularly on understanding the underlying mechanisms of such diseases, as in the field of epigenetics, and pay more attention to strengthening primary prevention. To date, preliminary research has found a connection between DNA methylation, histone modifications, RNA-based mechanisms and the development of CVD like atherosclerosis, cardiac hypertrophy, myocardial infarction, and heart failure. Several therapeutic agents based on the findings of such research projects are currently being tested for use in clinical practice. Although these tests have produced promising data so far, no epigenetically active agents or drugs targeting histone acetylation and/or methylation have actually entered clinical trials for CVDs, nor have they been approved by the FDA. To ensure the most effective prevention and treatment possible, further studies are required to understand the complex relationship between epigenetic regulation and the development of CVD. Similarly, several classes of RNA therapeutics are currently under development. The use of miRNAs and their targets as diagnostic or prognostic markers for CVDs is promising, but has not yet been realized. Further studies are necessary to improve our understanding of the involvement of lncRNA in regulating gene expression changes underlying heart failure. Through the data obtained from such studies, specific therapeutic strategies to avoid heart failure based on interference with incRNA pathways could be developed. Together, research and testing findings raise hope for enhancing the therapeutic armamentarium. This review presents the currently available data concerning epigenetic mechanisms and compounds involved in cardiovascular diseases, as well as preventive and therapeutic approaches against them.

MiR-126 inhibits vascular endothelial cell apoptosis through targeting PI3K/Akt signaling

BACKGROUND

MiR-126 is likely to be closely associated with the threatening disease deep venous thrombosis (DVT).

AIM

This study aims to investigate the influence of aberrantly expressed miR-126 on vascular endothelial cell (VEC) apoptosis during DVT and explore how miR-126 functions in it.

METHODS

MiR-126 inhibition and overexpression in vivo were respectively performed with antagomir and agomir of miR-126. Using a rat traumatic femoral DVT model, VEC apoptosis and miR-126 expression were detected by TUNEL assay and qRT-PCR before thrombogenesis and at different time phases of thrombogenesis. Protein levels of MMPs, Akt, Bcl-2, Bad, and caspase-9 in vascular tissue were measured by western blotting. In vitro, miR-126 interference, and overexpression were performed on human umbilical vein endothelial cells (HUVECs) using miR-126 inhibitor and mimics. After HUVECs were pretreated with CoCl2, cell apoptosis was analyzed using flow cytometry, and RNA/protein levels of miR-126, PIK3R2, PTEN, and phosphorylated Akts were measured with qRT-PC/western blotting.

RESULTS

The apoptosis of VECs was increased by miR-126 inhibition and obviously rescued by miR-126 overexpression. PI3K/Akt signal transduction was suppressed by miR-126 inhibition and evidently enhanced by miR-126 overexpression. Consistent with these findings, the downstream proteins (Bcl-2, Bad, and cleaved caspase-9) in PI3K/Akt pathway and the MMPs were remarkably changed by inhibition or overexpression of miR-126. In vitro experiments also showed that PI3K/Akt signaling was strengthened when miR-126 expression was upregulated or inhibited when miR-126 was knockdown.

CONCLUSION

Overexpressed miR-126 inhibits apoptosis of VECs and DVT through targeting the anti-apoptotic pathway PI3K/Akt via PIK3R2.

GENERAL SIGNIFICANCE

These findings may provide a new target for the therapy of DVT.

Oxidized low-density lipoprotein is a common risk factor for cardiovascular diseases and gastroenterological cancers via epigenomical regulation of microRNA-210

Hyperlipidemia, including the oxidized low-density lipoprotein (oxLDL) accumulation, is a risk and highly associated with the development of cancers and cardiovascular diseases. microRNA-210 (miR-210), a hypoxia-responsive microRNA regulated by HIF-1α, has been implicated in cancer and cardiovascular disease formation. Furthermore, Bioinformatics analysis revealed that the promoter of the miR-210 gene contains CpG-rich regions. It is unclear whether miR-210 expression could be epigenetically regulated in these disease progresses. The study aimed to explore the relationships between lipid and miR-210 in the context of cardiovascular disease and gastrointestinal cancer. We demonstrated oxLDL can decrease methylation in the miR-210 promoter to up-regulate miR-210. HIF-1α can bind to miR-210 promoter, but this HIF-1α binding site can be blocked by methylation. We showed that subjects of carotid atherosclerosis, stroke patients and cancer patients had hypomethylation in the miR-210 promoter, especially the HIF-1α binding site. Furthermore, miR-210 can directly inhibit sprouty-related EVH1 domain 2 (SPRED2) expressions, and SPRED2 reduces cell migration via ERK/c-Fos/MMPs pathways. Increased miR-210 and reduced SPRED2 levels were found in aorta of mice under high-fat diet and tumor tissues, which implied that miR-210 can be an underlying mechanism to explain oxLDL as a common risk factor for cardiovascular disease and gastrointestinal cancer.

CXCL16 in Vascular Pathology Research: from Macro Effects to microRNAs

Chemokines and their receptors have become significant factors in atherosclerosis research. CXCL16 is a multifunctional agent located on a separate locus to all other known chemokines and binds only to its "unique" receptor named CXCR6. As a scavenger receptor, adhesion molecule, and chemokine, it quickly became an interesting target in atherosclerosis research as all its functions have a role in vascular pathology. The investigation of the role of CXCL16 in atherosclerosis, although shown in in vitro studies, animal knockout models, and CXCL16 gene polymorphisms, haplotypes, and circulating levels, still shows puzzling results. Genetic and epigenetic studies have just scratched the surface of research necessary for a better assessment of the significance and perspective of this marker in plaque development and progression. In this review, we will summarize current knowledge about CXCL16 in atherosclerosis. Additionally, we will point out the importance of bioinformatics tools for the detection of potentially new CXCL16 regulatory networks through microRNA activity. This review aims to provide a better understanding of the underlying mechanisms, define more specific biomarkers, and discover new therapeutic targets.

Upregulation of miR-142-5p in atherosclerotic plaques and regulation of oxidized low-density lipoprotein-induced apoptosis in macrophages

MicroRNA (miR)-142-5p is a member of the miR-142 family, which have been shown to be associated with tumors, stem cells and disorders of the immune system. However, the role of miR-142-5p in atherosclerosis has yet to be investigated. In the present study, an atherosclerotic apolipoprotein E-deficient (apoE−/−) mouse model was constructed and fed a high-fat diet. The expression levels of miR-142-5p in the murine atherosclerotic plaques were detected by gene microarray analysis. In addition, an in vitro assay was used to determine the expression levels of miR-142-5p in human endothelial cells, smooth muscle cells and macrophages, which were treated with oxidized low-density lipoprotein (ox-LDL). Furthermore, a miR-142-5p inhibitor and mimic was transfected into cultured human macrophages, in order to observe the effects on transforming growth factor-β2 (TGF-β2) expression. The effects of co-transfection of the miR-142-5p inhibitor or mimic with TGF-β2, in human macrophages, on the rate of apoptosis was analyzed. The expression levels of miR-142-5p were 6.84-fold higher in mice with stable atherosclerotic plaques, and 2.69-fold higher in mice with vulnerable atherosclerotic plaques, as compared with the controls. Furthermore, the expression levels of miR-142-5p were upregulated in the cultured human macrophages. The percentage of apoptotic cells was lowest in the macrophages transfected with both TGF-β2 and miR-142-5p inhibitors and treated with ox-LDL. The expression levels of miR-142-5p were upregulated in the atherosclerotic plaques of the apoE−/− mice. The findings of the present study have shown that the upregulation of miR-142-5p expression may regulate apoptosis in human macrophages by targeting TGF-β2. This effect may have an important role in the progression of atherosclerosis.

Epigenetic reprogramming in atherosclerosis

Recent data support the involvement of epigenetic alterations in the pathogenesis of atherosclerosis. The most widely investigated epigenetic mechanism is DNA methylation although also histone code changes occur during the diverse steps of atherosclerosis, such as endothelial cell proliferation, vascular smooth muscle cell (SMC) differentiation, and inflammatory pathway activation. In this review, we focus on the main genes that are epigenetically modified during the atherogenic process, particularly nitric oxide synthase (NOS), estrogen receptors (ERs), collagen type XV alpha 1 (COL15A1), vascular endothelial growth factor receptor (VEGFR), and ten-eleven translocation (TET), which are involved in endothelial dysfunction; gamma interferon (IFN-γ), forkhead box p3 (FOXP3), and tumor necrosis factor-α (TNF-α), associated with atherosclerotic inflammatory process; and p66shc, lectin-like oxLDL receptor (LOX1), and apolipoprotein E (APOE) genes, which are regulated by high cholesterol and homocysteine (Hcy) levels. Furthermore, we also discuss the role of non-coding RNAs (ncRNA) in atherosclerosis. NcRNAs are involved in epigenetic regulation of endothelial function, SMC proliferation, cholesterol synthesis, lipid metabolism, and inflammatory response.