MicroRNAs in lipid metabolism and atherosclerosis

Inhibiting MiR-33a-3p Expression Fails to Enhance ApoAI-Mediated Cholesterol Efflux in Pro-Inflammatory Endothelial Cells

Background and Objectives: Atherosclerosis is an inflammatory condition that results in cholesterol accumulating within vessel wall cells. Atherosclerotic cardiovascular disease is the leading cause of mortality worldwide due to this disease being a major contributor to myocardial infarctions and cerebrovascular accidents. Research suggests that cholesterol accumulation occurring precisely within arterial endothelial cells triggers atherogenesis and exacerbates atherosclerosis. Furthermore, inflamed endothelium acts as a catalyst for atherosclerotic development. Therefore, enhancing cholesterol removal specifically in pro-inflammatory endothelial cells may be a potential treatment option for atherosclerosis. While we have previously shown that inhibiting the microRNA guide strand miR-33a-5p within pro-inflammatory endothelial cells increases both ABCA1 expression and apoAI-mediated cholesterol efflux, it is unknown whether inhibiting the miR-33a-3p passenger strand in pro-inflammatory endothelial cells causes similar atheroprotective effects. In this study, this is what we aimed to test. Materials and Methods: We used plasmid transfection to knockdown miR-33a-3p expression within cultured pro-inflammatory immortalized mouse aortic endothelial cells (iMAECs). We compared ABCA1 expression and apoAI-mediated cholesterol efflux within these cells to cultured pro-inflammatory iMAECs transfected with a control plasmid. Results: The knockdown of miR-33a-3p expression within pro-inflammatory iMAECs resulted in a significant increase in ABCA1 mRNA expression. However, the inhibition of miR-33a-3p did not significantly increase ABCA1 protein expression within pro-inflammatory iMAECs. Moreover, we failed to detect a significant increase in apoAI-mediated cholesterol efflux within pro-inflammatory iMAECs from miR-33a-3p knockdown. Conclusions: Our results indicative that the knockdown of miR-33a-3p alone does not enhance ABCA1-dependent cholesterol efflux within pro-inflammatory endothelial cells. To gain any atheroprotective benefit from inhibiting miR-33a-3p within pro-inflammatory endothelium, additional anti-atherogenic strategies would likely be needed in unison.

Preliminary Evidence Supports that Long-Term Consumption of Higher-Protein Breakfast Promotes Higher Expression of Select miRNA Associated with Cardiometabolic Health in Adolescents

BACKGROUND

Increased dietary protein at breakfast promotes cardiometabolic health; however, whether these improvements occur at the molecular level is unknown.

OBJECTIVES

The objective was to examine whether long-term consumption of breakfast, varying in protein quantity, alters the expression of circulating microRNAs (miRNAs) associated with cardiometabolic health in "breakfast-skipping" adolescents.

METHODS

Thirty adolescents (age: 19 ± 1 y; body mass index: 25.4 ± 3 kg/m2) completed a 6-mo tightly controlled breakfast trial in which participants consumed 350 kcal normal-protein (NP, 10 g protein) or higher-protein (HP, 30 g protein) breakfasts or continued to BS for 6 mo. Fasting blood samples were collected at baseline (PRE) and 6 mo (POST) for assessment of 12 a priori circulating plasma miRNA expression levels (real-time quantitative polymerase chain reaction), glucose, insulin, IL-6, and C-reactive protein.

RESULTS

No main effects of group were observed for any miRNAs; however, a time-by-group interaction was detected for the expression of miR-126-3p (P = 0.05). HP breakfast tended to increase miR-126-3p expression throughout the study (POST-PRE, P = 0.09) leading to greater expression at POST compared with BS (P = 0.03), whereas NP breakfast did not. Additionally, several miRNAs predicted fasting concentrations of IL-6: miR-320a-3p, -146a-5p, -150-5p, -423-5p, -122-5p, glucose: miR-24-3p, -126-3p; insulin: miR-24-3p, -126-3p, -15b-5p; insulin sensitivity: miR-24-3p, -126-3p, -199a-5p, -15b-5p; and β-cell function: miR-15b-5p (R2 between 0.2 and 0.39; P < 0.05) from PRE and POST samples across groups.

CONCLUSIONS

These data support the daily consumption of a HP breakfast to promote cardiometabolic health, potentially through changes in miRNA expression, in a sensitive life-stage where early intervention strategies are critical to reduce the risk of adult-onset chronic disease.

TRIAL REGISTRATION NUMBER

NCT03146442.

Toxicity assessment of di(2-ethylhexyl) phthalate using zebrafish embryos: Cardiotoxic potential

Plasticizers are considered as newly emerged contaminants. They are added to plastics to increase their flexibility and softness. Phthalate plasticizers including the Di-2-ethylhexyl phthalates (DEHP) are toxic and induce adverse effects on the different organization levels of the environment. In the current study, we investigated the potential toxicity of DEHP using Zebrafish as a biological model. Five ascending concentrations of DEHP were tested in embryos throughout 96 hpf: 0.0086, 0.086, 0.86, 8.6, and 86 mg/L. Embryotoxicity assessments revealed limited lethal effects on DEHP-exposed embryos, yet notable anticipation of the hatching process was observed at 48 hpf. Although DEHP showed negligible influence on the length and pericardial area of exposed embryos, it led to multiple bodily deformities. Gene expression analyses of key cardiogenic and inflammatory genes evidenced alterations in tbx20, bcl2, and il1b expression in Zebrafish embryos at 96 h post-fertilization. Results from the cardiac function analysis displayed that DEHP significantly affected the arterial pulse and linear velocity within the Posterior Cardinal Vein (PCV) of exposed fish. These findings strongly advance that even at low concentrations, DEHP can be considered as potential toxic agent, capable of inducing cardiotoxic effects.

Mechanisms of Abnormal Lipid Metabolism in the Pathogenesis of Disease

Lipid metabolism is a critical component in preserving homeostasis and health, and lipids are significant chemicals involved in energy metabolism in living things. With the growing interest in lipid metabolism in recent years, an increasing number of studies have demonstrated the close relationship between abnormalities in lipid metabolism and the development of numerous human diseases, including cancer, cardiovascular, neurological, and endocrine system diseases. Thus, understanding how aberrant lipid metabolism contributes to the development of related diseases and how it works offers a theoretical foundation for treating and preventing related human diseases as well as new avenues for the targeted treatment of related diseases. Therefore, we discuss the processes of aberrant lipid metabolism in various human diseases in this review, including diseases of the cardiovascular system, neurodegenerative diseases, endocrine system diseases (such as obesity and type 2 diabetes mellitus), and other diseases including cancer.

CDKN2B-AS1 may act as miR-92a-3p sponge in coronary artery disease

BACKGROUND

LncRNAs, miRNAs, and the sponge effect between them exert diverse biological influences on the pathogenesis and progression of coronary artery disease (CAD), thus necessitating an exploration of the lncRNA-miRNA-gene regulatory network in CAD.

METHODS

Expression profile GSE98583 was obtained from NCBI, containing the data of 12 CAD patients and 6 controls. Limma package was utilized to determine the differentially expressed genes (DEGs). Functional enrichment analysis was performed by DAVID. The CAD-related miRNA-DEG associations were retrieved via HMDD and miRTarBase, and the CAD-related lncRNA-miRNA associations were retrieved via LncRNADisease and starBase. The CAD-related lncRNA-miRNA-DEG regulatory network was constructed by combining these associations. The dual luciferase test was carried out to validate the connections among lncRNA, miRNA, and gene.

RESULTS

Overall, 534 DEGs were identified between CAD samples and controls, including 243 up-regulated and 291 down-regulated, and were enriched in various gene ontology biological processes and KEGG pathways. The CAD-related miRNAs targeting DEGs included hsa-miR-206, has-miR-320b, has-miR-4513, has-miR-765, and has-miR-92a-3p, and hsa-miR-92a-3p regulated the most DEGs. In the lncRNA-miRNA associations, only CDKN2B-AS1 regulated the CAD-related miRNA, hsa-miR-92a-3p, which was validated using the dual luciferase test.

CONCLUSIONS

CDKN2B-AS1 may act as an hsa-miR-92a-3p sponge to regulate the downstream DEGs in CAD. CDKN2B-AS1/ hsa-miR-92a-3p/GATA2 might be a novel mechanism for CAD.

Analysis of the therapeutic potential of miR-124 and miR-16 in non-alcoholic fatty liver disease

BACKGROUNDS

Non-alcoholic fatty liver disease (NAFLD) is a common condition affecting >25 % of the population worldwide. This disorder ranges in severity from simple steatosis (fat accumulation) to severe steatohepatitis (inflammation), fibrosis and, at its end-stage, liver cancer. A number of studies have identified overexpression of several key genes that are critical in the initiation and progression of NAFLD. MiRNAs are potential therapeutic agents that can regulate several genes simultaneously. Therefore, we transfected cell lines with two key miRNAs involved in targeting NAFLD-related genes.

METHODS

The suppression effects of the investigated miRNAs (miR-124 and miR-16) and genes (TNF, TLR4, SCD, FASN, SREBF2, and TGFβ-1) from our previous study were investigated by real-time PCR in Huh7 and HepG2 cells treated with oleic acid. Oil red O staining and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay were utilized to assess cell lipid accumulation and cytotoxic effects of the miRNAs, respectively. The pro-oxidant-antioxidant balance (PAB) assay was undertaken for miR-16 and miR-124 after cell transfection.

RESULTS

Following transfection of miRNAs into HepG2, oil red O staining showed miR-124 and miR-16 reduced oleic acid-induced lipid accumulation by 35.2 % and 28.6 % respectively (p < 0.05). In Huh7, miR-124 and miR-16 reduced accumulation by 23.5 % and 31.3 % respectively (p < 0.05) but without impacting anti-oxidant activity. Real-time PCR in HepG2 revealed miR-124 decreased expression of TNF by 0.13-fold, TLR4 by 0.12-fold and SREBF2 by 0.127-fold (p < 0.05). miR-16 decreased TLR4 by 0.66-fold and FASN by 0.3-fold (p < 0.05). In Huh7, miR-124 decreased TNF by 0.12-fold and FASN by 0.09-fold (p < 0.05). miR-16 decreased SCD by 0.28-fold and FASN by 0.64-fold (p < 0.05). MTT assays showed, in HepG2, viability was decreased 24.7 % by miR-124 and decreased 33 % by miR-16 at 72 h (p < 0.05). In Huh7, miR-124 decreased viability 42 % at 48 h and 29.33 % at 72 h (p < 0.05), while miR-16 decreased viability by 32.3 % (p < 0.05).

CONCLUSION

These results demonstrate the ability of miR-124 and miR-16 to significantly reduce lipid accumulation and expression of key pathogenic genes associated with NAFLD through direct targeting. Though this requires further in vivo investigation.

The effective constituent puerarin, from Pueraria lobata, inhibits the proliferation and inflammation of vascular smooth muscle in atherosclerosis through the miR-29b-3p/IGF1 pathway

CONTEXT

Atherosclerosis (AS) is the main cause of cardiovascular and cerebrovascular diseases. Pueraria lobata (Willd.) Ohwi (Fabaceae) has a positive effect on improving these diseases.

OBJECTIVE

The P. lobata effect on the proliferation and inflammation of vascular smooth muscle in AS and the potential mechanism were investigated.

MATERIALS AND METHODS

By feeding a high-fat diet to 8-week-old apolipoprotein E knockout mice, an atherosclerosis model was created. H&E and IHC staining were used to analyse the histopathology of mice. CCK-8, TUNEL, and scratch tests were used to detect cell proliferation, apoptosis, and migration after 24 h treatment, respectively. ELISA was performed to evaluate the level of IL-6 and IL-8. The target miRNA and its downstream target gene were screened by the bioinformatics method; RT-qPCR has conducted to analyse the expression of these genes.

RESULTS

In the aortic tissue and serum of AS mice, puerarin can lower the expression of α-SMA and the inflammatory proteins IL-6 and IL-8. Puerarin (200 M) decreased hVSMC proliferation, migration, and IL-6 and IL-8 secretion by more than half. The inhibitory impact of puerarin on hVSMC was decreased by overexpression of miR-29b-3p. IGF1 was miR-29b-3p's downstream target gene. IGF1 expression increased almost 3-fold in AS mice and hVSMC, but miR-29b-3p mimic inhibited it. The effect of miR-29b-3p on hVSMC was reversed when IGF1 was overexpressed.

DISCUSSION AND CONCLUSIONS

Puerarin inhibits the proliferation and inflammation of vascular smooth muscle in AS through the miR-29b-3p/IGF1 pathway. Puerarin may have a beneficial effect in the treatment of atherosclerosis and offer a novel therapy option.

microRNA-223 and microRNA-126 are clinical indicators for predicting the plaque stability in carotid atherosclerosis patients

Studies have demonstrated the essential functions of microRNAs (miRNAs) in cardiovascular disease. Herein, we explored the roles of miR-126 and miR-223 in the prediction of plaque stability in carotid atherosclerosis (CA).Patients with CA (N = 52) and healthy volunteers (N = 25) were recruited as the study subjects and controls. First, a miRNA microarray was performed to analyze the differentially expressed miRNAs in the serum of normal controls and patients with CA. Next, the correlations of miR-223 and miR-126 expression with plaque stability-related factors were analyzed. Then, the predictive efficacy of miR-223 and miR-126 on plaque stability was analyzed by the ROC curve, and the targeting relationships of miR-223 and miR-126 with COX2 were verified. Finally, the relationship between COX2 expression and CA plaque stability was analyzed. miR-223 and miR-126 were decreased in the serum of CA patients and had good diagnostic efficacy for CA. miR-223 and miR-126 in the serum of CA patients with unstable plaques were lower than that in patients with stable plaques. miR-223 and miR-126 were negatively correlated with plaque instability-related indicators, while COX2, a direct target of miR-223 and miR-126, was positively related to plaque instability-related indicators. Lowly expressed miR-223 and miR-126 in the serum of CA patients can be used as indicators for plaque stability.

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

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

Mechanoimmunology: Are inflammatory epigenetic states of macrophages tuned by biophysical factors?

Many inflammatory diseases that are responsible for a majority of deaths are still uncurable, in part as the underpinning pathomechanisms and how to combat them is still poorly understood. Tissue-resident macrophages play pivotal roles in the maintenance of tissue homeostasis, but if they gradually convert to proinflammatory phenotypes, or if blood-born proinflammatory macrophages persist long-term after activation, they contribute to chronic inflammation and fibrosis. While biochemical factors and how they regulate the inflammatory transcriptional response of macrophages have been at the forefront of research to identify targets for therapeutic interventions, evidence is increasing that physical factors also tune the macrophage phenotype. Recently, several mechanisms have emerged as to how physical factors impact the mechanobiology of macrophages, from the nuclear translocation of transcription factors to epigenetic modifications, perhaps even DNA methylation. Insight into the mechanobiology of macrophages and associated epigenetic modifications will deliver novel therapeutic options going forward, particularly in the context of increased inflammation with advancing age and age-related diseases. We review here how biophysical factors can co-regulate pro-inflammatory gene expression and epigenetic modifications and identify knowledge gaps that require urgent attention if this therapeutic potential is to be realized.

Integrated investigation of DNA methylation, gene expression and immune cell population revealed immune cell infiltration associated with atherosclerotic plaque formation

BACKGROUND

The clinical consequences of atherosclerosis are significant source of morbidity and mortality throughout the world, while the molecular mechanisms of the pathogenesis of atherosclerosis are largely unknown.

METHODS

In this study, we integrated the DNA methylation and gene expression data in atherosclerotic plaque samples to decipher the underlying association between epigenetic and transcriptional regulation. Immune cell classification was performed on the basis of the expression pattern of detected genes. Finally, we selected ten genes with dysregulated methylation and expression levels for RT-qPCR validation.

RESULTS

Global DNA methylation profile showed obvious changes between normal aortic and atherosclerotic lesion tissues. We found that differentially methylated genes (DMGs) and differentially expressed genes (DEGs) were highly associated with atherosclerosis by being enriched in atherosclerotic plaque formation-related pathways, including cell adhesion and extracellular matrix organization. Immune cell fraction analysis revealed that a large number of immune cells, especially macrophages, activated mast cells, NK cells, and Tfh cells, were specifically enriched in the plaque. DEGs associated with immune cell fraction change showed that they were mainly related to the level of macrophages, monocytes, resting NK cells, activated CD4 memory T cells, and gamma delta T cells. These genes were highly enriched in multiple pathways of atherosclerotic plaque formation, including blood vessel remodeling, collagen fiber organization, cell adhesion, collagen catalogic process, extractable matrix assembly, and platelet activation. We also validated the expression alteration of ten genes associated with infiltrating immune cells in atherosclerosis.

CONCLUSIONS

In conclusion, these findings provide new evidence for understanding the mechanisms of atherosclerotic plaque formation, and provide a new and valuable research direction based on immune cell infiltration.

miR-1290 promotes IL-8-mediated vascular endothelial cell adhesion by targeting GSK-3β

BACKGROUND

MicroRNA-1290 (miR-1290) has been reported to be involved in many diseases and play a key role during the development process. However, the role of miR-1290 in atherosclerosis (AS) is still unclear.

METHODS AND RESULTS

The current study showed that the expressions of miR-1290 were high in serum of patients with hyperlipidemia. The functional role of miR-1290 were then investigated in human umbilical vein endothelial cells (HUVECs). Here, we found that miR-1290 expressions were notably enhanced in HUVECs mediated by IL-8. miR-1290 inhibitor repressed monocytic THP-1 cells adhesion to HUVECs by regulating ICAM-1 and VCAM-1, inhibited proliferation through regulating cyclinD1 and PCNA, and inhibited inflammatory response by regulating IL-1β. Mechanistically, we verified that miR-1290 mimic was able to directly target the 3'-UTR of GSK-3β mRNA using luciferase reporter assay. Knockdown of GSK-3β (si-GSK-3β) promoted HUVECs adhesion and the expression of IL-1β, and partially restore the depression effect of miR-1290 inhibitor on HUVECs adhesion and inflammation. In contrast, si-GSK-3β inhibited the proliferation of HUVECs and the expression of cyclinD1 and PCNA.

CONCLUSIONS

In summary, our study revealed that miR-1290 promotes IL-8-mediated the adhesion of HUVECs by targeting GSK-3β. However, GSK-3β is not the target protein for miR-1290 to regulate the proliferation of HUVECs. Our findings may provide potential target in atherosclerosis treatment.

Mechanosensitive pathways are regulated by mechanosensitive miRNA clusters in endothelial cells

Shear stress is known to affect many processes in (patho-) physiology through a complex, multi-molecular mechanism, termed mechanotransduction. The sheer complexity of the process has raised questions how mechanotransduction is regulated. Here, we comprehensively evaluate the literature about the role of small non-coding miRNA in the regulation of mechanotransduction. Regulation of mRNA by miRNA is rather complex, depending not only on the concentration of mRNA to miRNA, but also on the amount of mRNA competing for a single mRNA. The only mechanism to counteract the latter factor is through overarching structures of miRNA. Indeed, two overarching structures are present miRNA families and miRNA clusters, and both will be discussed in details, regarding the latest literature and a previous conducted study focussed on mechanotransduction. Both the literature and our own data support a new hypothesis that miRNA-clusters predominantly regulate mechanotransduction, affecting 65% of signalling pathways. In conclusion, a new and important mode of regulation of mechanotransduction is proposed, based on miRNA clusters. This finding implicates new avenues for treatment of mechanotransduction and atherosclerosis.

Induction of microRNA hsa-let-7d-5p, and repression of HMGA2, contribute protection against lipid accumulation in macrophage 'foam' cells

Accumulation of excess cholesterol and cholesteryl ester in macrophage 'foam' cells within the arterial intima characterises early 'fatty streak' atherosclerotic lesions, and is accompanied by epigenetic changes, including altered expression of microRNA sequences which determine of gene and protein expression. This study established that exposure to lipoproteins, including acetylated LDL, induced macrophage expression of microRNA hsa-let-7d-5p, a sequence previously linked with tumour suppression, and repressed expression of one of its target genes, high mobility group AT hook 2 (HMGA2). A let-7d-5p mimic repressed expression of HMGA2 (18%; p < 0.05) while a marked increase (2.9-fold; p < 0.05) in expression of HMGA2 was noted in the presence of let-7d-5p inhibitor. Under these conditions, let-7d-5p mimic significantly (p < 0.05) decreased total (10%), free (8%) and cholesteryl ester (21%) mass, while the inhibitor significantly (p < 0.05) increased total (29%) and free cholesterol (29%) mass, compared with the relevant controls. Let-7d-5p inhibition significantly (p < 0.05) increased endogenous biosynthesis of cholesterol (38%) and cholesteryl ester (39%) pools in macrophage 'foam' cells, without altering the cholesterol efflux pathway, or esterification of exogenous radiolabelled oleate. Let-7d-5p inhibition in sterol-loaded cells increased the level of HMGA2 protein (32%; p < 0.05), while SiRNA knockdown of this protein (29%; p < 0.05) resulted in a (21%, p < 0.05) reduction in free cholesterol mass. Thus, induction of let-7d-5p, and repression of its target HMGA2, in macrophages is a protective response to the challenge of increased cholesterol influx into these cells; dysregulation of this response may contribute to atherosclerosis and other disorders such as cancer.

miR-141-5p suppresses vascular smooth muscle cell inflammation, proliferation, and migration via inhibiting the HMGB1/NF-κB pathway

MicroRNAs (miRNAs) have been identified as significant modulators in the pathogenesis of atherosclerosis (AS). Additionally, the dysregulation of vascular smooth muscle cells (VSMCs) is a crucial biological event during AS. Our study aimed to explore the functional roles and molecular mechanisms of miR-141-5p in VSMCs dysfunction. C57BL/6 mice were used to establish AS animal model. Human VSMCs were treated by oxidized low-density lipoprotein (ox-LDL) to establish AS cell model. Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to probe miR-141-5p and high-mobility group box 1 (HMGB1) mRNA expressions in VSMCs or plasma samples of the mice. Inflammatory cytokines were detected by enzyme-linked immunosorbent assay kits. Cell counting kit-8 and bromodeoxyuridine assays were performed to evaluate cell proliferation. Cell migration and apoptosis were detected with Transwell assay and flow cytometry analysis, respectively. The target gene of miR-141-5p was predicted with the TargetScan database, and the interaction between miR-141-5p and HMGB1/nuclear factor-κB (NF-κB) was further validated by dual-luciferase reporter assay, qRT-PCR, and Western blot analysis. miR-141-5p was found to be decreased in the plasma of patients and mice model with AS. Its expression was also downregulated in VSMCs treated by ox-LDL. miR-141-5p overexpression inhibited the inflammation, proliferation, migration of VSMCs, and promoted the apoptosis of VSMCs. HMGB1 was identified as a direct target of miR-141-5p, and miR-141-5p could repress the activity of HMGB1/NF-κB signaling. HMGB1 restoration reversed the effects of miR-141-5p, and NF-κB inhibitor JSH-23 showed similar effects with miR-141-5p mimics. miR-141-5p inhibits VSMCs' dysfunction by targeting the HMGB1/NF-κB pathway, which probably functions as a protective factor during the development of AS.

miR-21-5p Regulates the Proliferation and Differentiation of Skeletal Muscle Satellite Cells by Targeting KLF3 in Chicken

The proliferation and differentiation of skeletal muscle satellite cells (SMSCs) play an important role in the development of skeletal muscle. Our previous sequencing data showed that miR-21-5p is one of the most abundant miRNAs in chicken skeletal muscle. Therefore, in this study, the spatiotemporal expression of miR-21-5p and its effects on skeletal muscle development of chickens were explored using in vitro cultured SMSCs as a model. The results in this study showed that miR-21-5p was highly expressed in the skeletal muscle of chickens. The overexpression of miR-21-5p promoted the proliferation of SMSCs as evidenced by increased cell viability, increased cell number in the proliferative phase, and increased mRNA and protein expression of proliferation markers including PCNA, CDK2, and CCND1. Moreover, it was revealed that miR-21-5p promotes the formation of myotubes by modulating the expression of myogenic markers including MyoG, MyoD, and MyHC, whereas knockdown of miR-21-5p showed the opposite result. Gene prediction and dual fluorescence analysis confirmed that KLF3 was one of the direct target genes of miR-21-5p. We confirmed that, contrary to the function of miR-21-5p, KLF3 plays a negative role in the proliferation and differentiation of SMSCs. Si-KLF3 promotes cell number and proliferation activity, as well as the cell differentiation processes. Our results demonstrated that miR-21-5p promotes the proliferation and differentiation of SMSCs by targeting KLF3. Collectively, the results obtained in this study laid a foundation for exploring the mechanism through which miR-21-5p regulates SMSCs.

Long non-coding RNA GAS5 knockdown facilitates proliferation and impedes apoptosis by regulating miR-128-3p/FBLN2 axis in ox-LDL-induced THP-1 cells

BACKGROUND

Long non-coding RNAs (lncRNAs) are found to involve in modulating the development of atherosclerosis (AS). But the molecular mechanism of lncRNA growth-arrest specific transcript 5 (GAS5) in AS is not fully understood.

METHODS

QRT-PCR was performed to measure the abundances of GAS5, miR-128-3p and fibulin 2 (FBLN2). Oxidized low-density lipoprotein (ox-LDL)-treated THP-1 cells were employed as cell models of AS. The cell proliferation and apoptosis were analyzed using CCK-8 and Flow cytometry assays, respectively. Levels of all protein were examined by western blot. The interaction among GAS5, miR-128-3p and FBLN2 was confirmed via dual-luciferase reporter and RNA immunoprecipitation (RIP) assays.

RESULTS

GAS5 was elevated and miR-128-3p was decreased in the serum of patients with AS and ox-LDL-stimulated THP-1 cells. Ox-LDL stimulation inhibited proliferation and induced apoptosis of THP-1 cells. Meanwhile, GAS5 directly targeted miR-128-3p and inversely modulated its expression. Importantly, GAS5 depletion facilitated cell proliferation and impaired apoptosis in ox-LDL-induced THP-1 cells. Additionally, GAS5 augmented FBLN2 expression through sponging miR-128-3p, and miR-128-3p facilitated proliferation and retarded apoptosis of ox-LDL-induced THP-1 cells by targeting FBLN2.

CONCLUSION

GAS5 knockdown promoted the growth of ox-LDL-induced THP-1 cells through down-modulating FBLN2 and increasing miR-128-3p, suggesting the potential value of GAS5 for treatment of AS.

Responses of functional miRNA-mRNA regulatory modules to a high-fat diet in the liver of hybrid yellow catfish (Pelteobagrus fulvidraco × P. vachelli)

Fatty liver disease is common in cultured yellow catfish as a result of high fat contents in feeds. However, little is known about the mechanism by which the excessive deposition of liver fat causes fatty liver disease. Hybrid yellow catfish (Pelteobagrus fulvidraco♀ × P. vachelli♂) were fed a high-fat diet (HFD) or a normal-fat diet (NFD) for 60 days. Compared with the NFD group, the HFD group showed lower growth performance, higher hepatosomatic and viscerosomatic indexes, increased hepatic triglyceride and cholesterol contents, and more and larger lipid droplets in liver tissue. Whole transcriptome mRNA libraries and microRNA libraries from fish in the NFD and HFD groups were constructed by high-throughput sequencing. Twelve miRNAs were differentially expressed (DE) between the HFD and NFD groups. Seven negatively correlated DE miRNA-DE mRNA pairs were selected, and the expression patterns of both were confirmed using qRT-PCR. Hybrid yellow catfish showed mediated oxidative degradation of liver glucose and fatty acid peroxidation, regulation of antioxidant enzyme activity, and various immune and inflammatory responses to fat deposition and stress. These findings have important biological significance for protecting the liver against stress, as well as economic significance for establishing healthy aquaculture conditions.

Lipolysis by downregulating miR-92a activates the Wnt/β-catenin signaling pathway in hypoxic rats

The aim of the present study was to investigate the role of miR-92a in lipid metabolism in hypoxic rats. Microarray analysis and reverse transcription-quantitative (RT-q)PCR were used to detect changes in the mRNA expression levels of miR-92a in the epididymal fat of hypoxic and normoxic rats. The downstream target mRNA of miR-92a was predicted using bioinformatics analysis and verified using a dual luciferase reporter assay. Changes in the expression of frizzled (Fzd)10 and c-Myc in the epididymal fat were detected using RT-qPCR and western blotting. Microarray analysis and RT-qPCR results showed that the expression of miR-92a was significantly lower in the fat tissues of the hypoxic rats compared with the normoxic rats. The results of the dual luciferase reporter assay showed that the target gene of miR-92a was Fzd10, which is an acceptor in the Wnt pathway. Fzd10 expression was upregulated in the hypoxic rats. The mRNA expression levels of c-Myc, which is located downstream of the Wnt pathway, was increased significantly. The increase in the mRNA and protein expression levels of Fzd10 and c-Myc may be associated with miR-92a downregulation. Downregulation of miR-92a in-turn may result in lipolysis through the regulation of the Wnt/β-catenin signaling pathway, and thus weight loss in the rats.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and Polychlorinated Biphenyl Coexposure Alters the Expression Profile of MicroRNAs in the Liver Associated with Atherosclerosis

MicroRNAs (miRNAs) are a class of small RNAs that regulate gene expression. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and polychlorinated biphenyls (PCBs) are persistent organic pollutants that exist as complex mixtures in vivo. When humans are simultaneously exposed to these compounds, the development of atherosclerosis is known to be enhanced. However, the roles of miRNA in TCDD- and PCB-induced atherosclerosis are largely unknown. Therefore, the present study is aimed at elucidating the possible dysregulation of miRNAs in atherogenesis induced by coexposure to TCDD and PCBs. Eight-week-old male ApoE^−/− mice were coexposed to TCDD (15 μg/kg) and Aroclor1254 (55 mg/kg, a representative mixture of PCBs) by intraperitoneal injection four times over a 6-week period. Microarray analysis of miRNAs and mRNAs in the liver of ApoE^−/− mice with or without TCDD and Aroclor1254 coexposure was performed. We discovered that 68 miRNAs and 1312 mRNAs exhibited significant expression changes in response to TCDD and PCB coexposure and revealed that both changed miRNAs and mRNAs are involved in cardiovascular disease processes. An integrated miRNA-mRNA approach indicated that miRNA-26a-5p, miRNA-193a-3p, and miRNA-30c-5p participated in specific TCDD and Aroclor1254 coresponsive networks which are relevant to the cardiovascular system development and function network. Furthermore, our results also indicated that miRNA-130a-3p and miRNA-376a-3p were novel players in the regulation of TCDD- and Aroclor1254-induced atherosclerosis pathways. In summary, our finding provided new insights into the mechanism of atherosclerosis in response to TCDD and PCB coexposure.

MicroRNA sequences modulating inflammation and lipid accumulation in macrophage “foam” cells: Implications for atherosclerosis

Accumulation of macrophage “foam” cells, laden with cholesterol and cholesteryl ester, within the intima of large arteries, is a hallmark of early “fatty streak” lesions which can progress to complex, multicellular atheromatous plaques, involving lipoproteins from the bloodstream and cells of the innate and adaptive immune response. Sterol accumulation triggers induction of genes encoding proteins mediating the atheroprotective cholesterol efflux pathway. Within the arterial intima, however, this mechanism is overwhelmed, leading to distinct changes in macrophage phenotype and inflammatory status. Over the last decade marked gains have been made in understanding of the epigenetic landscape which influence macrophage function, and in particular the importance of small non-coding micro-RNA (miRNA) sequences in this context. This review identifies some of the miRNA sequences which play a key role in regulating “foam” cell formation and atherogenesis, highlighting sequences involved in cholesterol accumulation, those influencing inflammation in sterol-loaded cells, and novel sequences and pathways which may offer new strategies to influence macrophage function within atherosclerotic lesions.

CTBP1‑AS2 inhibits proliferation and induces autophagy in ox‑LDL‑stimulated vascular smooth muscle cells by regulating miR‑195‑5p/ATG14

Atherosclerosis (AS) is a chronic progressive disease caused by injury and functional changes in vascular smooth muscle cells (VSMCs). Long non‑coding RNAs (lncRNAs) are pivotal regulators in AS development. The present study aimed to explore the roles and molecular mechanisms of lncRNA CTBP1‑AS2 in AS progression. A dual‑luciferase reporter assay confirmed that miR‑195‑5p is a downstream target miRNA of lncRNA CTBP1‑AS2 and miR‑195‑5p was increased in AS. The expression levels of miR‑195‑5p and CTBP1‑AS2 in the serums of patients with AS and human aorta vascular smooth muscle cells was increased or decreased, respectively, following treatment with oxidized low‑density lipoprotein (ox‑LDL). Functional experiments showed that the overexpression of lncRNA CTBP1‑AS2 inhibited the proliferation of HA‑VSMCs and promoted their autophagy following ox‑LDL treatment. This effect could be reversed by treatment with ROC‑325, the inhibitor of autophagy, or miR‑195‑5p mimics. Autophagy related 14 (ATG14) was identified to be a target of miR‑195‑5p, and lncRNA CTBP1‑AS2 promoted ATG14 expression by serving as a competing endogenous RNA of miR‑195‑5p. The present study revealed that lncRNA CTBP1‑AS2 may serve a role in AS by inhibiting the proliferation and promoting the autophagy of VSMCs through ATG14 modulation via miR‑195‑5p. These data may provide a novel therapeutic target for AS.

MicroRNAs as the actors in the atherosclerosis scenario

Atherosclerosis is considered as the most common cardiovascular disease and a leading cause of global mortality, which develops through consecutive steps. Various cellular and molecular biomarkers such as microRNAs are identified to be involved in atherosclerosis progression. MicroRNAs are a group of endogenous, short, non-coding RNAs, which are able to bind to specific sequences on target messenger RNAs and thereby modulate gene expression post-transcriptionally. MicroRNAs are key players in wide range of biological processes; thus, their expression level is regulated in pathophysiological conditions. Ample evidences including in vitro and in vivo studies approved a critical role of microRNAs in epigenetic and the sequential processes of atherosclerosis from risk factors to plaque formation, progression, and rupture. Based on these findings, miRNAs seems to be promising candidates for therapeutic approach. This review summarizes the role of miRNAs in atherosclerosis development, epigenetic, and therapy. Moreover, the application of exosomes in miRNA delivery, and/or their prognostic and diagnostic values are also discussed.

Effect of microRNA-144-5p on the proliferation, invasion and migration of human umbilical vein endothelial cells by targeting SMAD1

Atherosclerosis is a multifactorial chronic disease that is a major cause of death and injury worldwide. Apoptosis of endothelial cells (ECs) serves an important role in the occurrence and development of atherosclerosis. MicroRNAs (miRNAs) serve a key role in atherosclerosis though regulating the function of ECs. At present, the role of miRNA-144-5p (miR-144-5p) in atherosclerosis is unclear. The aim of this study was to investigate the effect of miR-144-5p on atherosclerosis in oxidized low-density lipoprotein (ox-LDL)-stimulated human umbilical vein endothelial cells (HUVECs). Results from the present study demonstrated that miR-144-5p overexpression could inhibit proliferation and induce apoptosis in HUVECs. To further study the biological function of miR-144-5p, the effects of modulating miR-144-5p expression on the invasion and migration of HUVECs were also examined. The results demonstrated that miR-144-5p upregulation suppressed HUVEC migration and invasion. TargetScan and dual luciferase reporter assay results demonstrated that SMAD1 was a direct target gene of miR-144-5p. miR-144-5p upregulation inhibited the expression of phosphorylated-SMAD1/5/8 in the SMAD pathway. In conclusion, the data indicated that miR-144-5p serves an important role in the development of atherosclerosis through regulating the function of HUVECs by targeting SMAD1.

Triptolide inhibits angiogenesis in microvascular endothelial cells through regulation of miR-92a

Atherosclerosis is one common chronic inflammatory disease in which angiogenesis is involved. Here we established an in vitro cell model of angiogenesis made by human dermal microvascular endothelial cells (HMEC-1) and work to investigate the role of triptolide (TPL) in this model. To induce angiogenesis, HMEC-1 cells were cultured in Matrigel-conditioned medium. The ratio of tubes to nucleus was detected. To evaluate angiogenesis, Western blot assay was carried out to detect endothelial nitric oxide synthase (eNOS), vascular endothelial growth factor receptor-2 (VEGFR2) and VEGF. Cell counting kit-8 was utilized to estimate the viability of HMEC-1 cells. microRNA (miR)-92a was analyzed by qRT-PCR. The targeting relationship between integrin subunit alpha 5 (ITGA5) and miR-92a was verified through luciferase activity assay. The effects of ITGA5 on signaling transducers (ERK, PI3K, and AKT) in a phosphorylated form were valued using Western blot method. After stimulated by TPL, LY294002 and PD98059, the alteration in phosphorylation of the signaling transducers was evaluated by Western blot assay. The ratio of tubes to nucleus and angiogenesis related factors were increased with the delaying of culture time. TPL decreased the expression of angiogenesis factors. Furthermore, miR-92a was upregulated by TPL and miR-92a silence upregulated angiogenesis factors. In addition, TPL decreased ITGA5 which was proved as a target of miR-92a. ITGA5 overexpression resulted in the abundance of angiogenesis factors while ITGA5 silence led to the opposite results. Meanwhile, ITGA5 overexpression increased phosphorylation of ERK, PI3K and AKT while ITGA5 silence reversed the trend. TPL (as an anti-angiogenesis agent) suppressed angiogenesis by upregulating miR-92a, and miR-92a-mediated down-regulation of ITGA5 blocked the signaling transduction of ERK and PI3K/AKT pathways.

MicroRNA-148a-3p promotes survival and migration of endothelial cells isolated from Apoe deficient mice through restricting circular RNA 0003575

The incidence of atherosclerosis is greatly increased, which becomes the leading cause for the death and disability worldwide. Endothelial cells dysfunction plays a substantial role in the pathogenesis of atherosclerosis. MicroRNA-148a-3p (miR-148a-3p) and circular RNA 0003575 (circ_0003575) modulated lipid metabolism and proliferative function of endothelial cells, respectively. However, the role of them in modulation of endothelial cell function and progression of atherosclerosis remains unknown. Endothelial cells were isolated from the aorta of Apoe^-/- mice. miR-148a-3p in atherosclerosis patients and healthy controls were measured by qRT-PCR. Overexpression and knockdown of miR-148a-3p in endothelial cells were established. The proliferation, migration and apoptosis of endothelial cells were measured by MTT, Transwell, and fluorescence microscope, respectively. Online software (miRWalk 2.0 and RegRNA2.0) and databases (miRWalk, miRanda, RNA22, and Targetscan) were used to predict potential target genes of miR-148a-3p and circ_0003575. The expression of target genes was detected through western blotting. The expression of miR-148a-3p was significantly upregulated in patients with atherosclerosis as relative to healthy people. Overexpression of miR-148a-3p exhibited stimulatory effects on endothelial cell proliferation and migration and inhibited programmed cell death. Six intersection target genes, c-MAF, FOXO4, FOXO3, MITF, ETV7, and CRX, were predicted between miR-148a-3p and circ_0003575. The opposite effects of circ_0003575 and miR-148a-3p on the expression of FOXO4 and FOXO3, which are essential for lipid metabolism. We demonstrate that miR-148a-3p suppresses FOXO4 and FOXO3 expression via interruption of circ_0003575 function, which in turn impairs the proliferative and migratory function of endothelial cells, eventually exacerbating the atherosclerosis.

Metformin promotes proliferation and suppresses apoptosis in Ox-LDL stimulated macrophages by regulating the miR-34a/Bcl2 axis

Background: Metformin, an antidiabetic drug, has been reported to be involved in atherosclerosis (AS). In this study, the effects of metformin on oxidized low-density lipoprotein (Ox-LDL)-induced macrophage apoptosis were investigated, and the mechanisms involved in this process were examined. Methods: qRT-qPCR analysis was performed to detect the expression of miR-34a in macrophage cells. Cell proliferation was determined by MTT assays and colony formation assays. Cell apoptosis was assessed by the detection of apoptotic rate and caspase 3 activity. Western blot analysis was performed to evaluate the expression of Bcl2 protein. Results: Metformin treatment promoted proliferation and suppressed apoptosis in macrophages following the treatment of oxidized low-density lipoprotein (Ox-LDL). Metformin could inhibit miR-34a in macrophages. miR-34a overexpression could reverse the effect of metformin on proliferation and apoptosis in Ox-LDL-treated macrophages. Moreover, metformin could increase the expression of the miR-34a target gene Bcl2. Furthermore, metformin treatment exerted the pro-proliferation and anti-apoptosis effect through regulating Bcl2 expression in Ox-LDL-stimulated macrophages. Conclusion: Metformin facilitated proliferation and inhibited apoptosis of macrophages treated with Ox-LDL through the miR-34a/Bcl2 axis, indicating the potential value of metformin in AS therapy.

MicroRNA-92a promotes vascular smooth muscle cell proliferation and migration through the ROCK/MLCK signalling pathway

To identify the interaction between known regulators of atherosclerosis, microRNA-92a (miR-92a), Rho-associated coiled-coil-forming kinase (ROCK) and myosin light chain kinase (MLCK), we examined their expressions during proliferation and migration of platelet-derived growth factor-BB (PDGF-BB)-regulated vascular smooth muscle cells (VSMCs), both in vivo and in vitro. During the formation of atherosclerosis plaque in mice, a parallel increase in expression levels of MLCK and miR-92a was observed while miR-92a expression was reduced in ML-7 (an inhibitor of MLCK) treated mice and in MLCK-deficient VSMCs. In vitro results indicated that both MLCK and miR-92a shared the same signalling pathway. Transfection of miR-92a mimic partially restored the effect of MLCK's deficiency and antagonized the effect of Y27632 (an inhibitor of ROCK) on the down-regulation of VSMCs activities. ML-7 increased the expression of Kruppel-like factor 4 (KLF4, a target of miR-92a), and siRNA-KLF4 increased VSMCs' activity level. Consistently, inhibition of either MLCK or ROCK enhanced the KLF4 expression. Moreover, we observed that ROCK/MLCK up-regulated miR-92a expression in VSMCs through signal transducer and activator of transcription 3 (STAT3) activation. In conclusion, the activation of ROCK/STAT3 and/or MLCK/STAT3 may up-regulate miR-92a expression, which subsequently inhibits KLF4 expression and promotes PDGF-BB-mediated proliferation and migration of VSMCs. This new downstream node in the ROCK/MLCK signalling pathway may offer a potential intervention target for treatment of atherosclerosis.

Circulating microRNA-92a level predicts acute coronary syndrome in diabetic patients with coronary heart disease

PURPOSE

This study was designed to explore the value of monitoring miR-92a in T2DM patients with coronary heart disease (CHD).

MATERIALS AND METHODS

40 ACS patients with prior history of CHD and diabetes while the onset time of diabetes preceded that of CHD by more than 2 years were enrolled as the DACS group(diabetic ACS group). 40 ACS subjects who had had a definite diagnosis of CHD for more than 2 years with no history of T2DM were recuited as the CACS group(chronic CHD with ACS group). All enrolled subjects from DACS and CACS group came from an emergency basis and diagnosed with ACS by coronary angiography. Another 68 age- and sex-matched volunteers with chronic stable CHD without diabetes history were assigned as the control group (CHD group). We examined the serum levels of miR-92a and analyzed their correlations with blood pressure, glucose level, and lipid level.

RESULTS

The levels of miR-92a were significantly elevated in the DACS group compared with those of the CACS and CHD groups. Multivariate analysis showed that miR-92a, systolic blood pressure (SBP), and glycosylated hemoglobin (HbA1c) were significantly related to ACS events in patients with T2DM. Forward stepwise binary logistic regression analysis identified miR-92a as an independent predictive factor for ACS events in the patients with T2DM.

CONCLUSION

An elevated circulating miR-92a level was associated with an increased risk of ACS in CHD patients with T2DM. Thus the level of miR-92a, especially combined with elevated SBP and HbA1c, may be helpful in the detection of ACS in patients with T2DM.

Retracted Article: MicroRNA-135a alleviates lipid accumulation and inflammation of atherosclerosis through targeting lipoprotein lipase

MicroRNAs (miRNAs) have recently attracted increasing attention for their involvement in atherosclerosis (AS). The purpose of this study was to further explore the function and underlying mechanism of miR-135a in AS progression. The expression levels of miR-135a and lipoprotein lipase (LPL) mRNA were detected by qRT-PCR, and LPL protein expression was measured by western blotting. The levels of blood lipids and inflammatory cytokines, and LPL activity were assessed using corresponding Assay Kits, and an HPLC assay was used to determine the levels of free cholesterol (FC), total cholesterol (TC) and cholesterol ester (CE). A Dil-oxLDL binding assay was performed to evaluate the ability of cholesterol uptake. The direct interaction between miR-135a and LPL was confirmed by a dual-luciferase reporter assay and RNA immunoprecipitation assay. Our data indicated that miR-135a was downregulated in serum samples of AS patients and mice. Upregulation of miR-135a alleviated lipid metabolic disorders and inflammation in AS mice. Moreover, miR-135a negatively regulated lipid accumulation and inflammation in ox-LDL-treated THP-1 macrophages. Mechanistically, miR-135a directly targeted LPL and repressed LPL expression. LPL mediated the regulatory effect of miR-135a on lipid accumulation and inflammation in ox-LDL-treated THP-1 macrophages. In conclusion, our study indicated that miR-135a upregulation ameliorated lipid accumulation and inflammation at least partly by targeting LPL in THP-1 macrophages, highlighting miR-135a as a potential antiatherogenic agent.

MicroRNAs (miRNAs) have recently attracted increasing attention for their involvement in atherosclerosis (AS).

Cholesterol transport system: An integrated cholesterol transport model involved in atherosclerosis

Atherosclerosis, the pathological basis of most cardiovascular disease (CVD), is closely associated with cholesterol accumulation in the arterial intima. Excessive cholesterol is removed by the reverse cholesterol transport (RCT) pathway, representing a major antiatherogenic mechanism. In addition to the RCT, other pathways are required for maintaining the whole-body cholesterol homeostasis. Thus, we propose a working model of integrated cholesterol transport, termed the cholesterol transport system (CTS), to describe body cholesterol metabolism. The novel model not only involves the classical view of RCT but also contains other steps, such as cholesterol absorption in the small intestine, low-density lipoprotein uptake by the liver, and transintestinal cholesterol excretion. Extensive studies have shown that dysfunctional CTS is one of the major causes for hypercholesterolemia and atherosclerosis. Currently, several drugs are available to improve the CTS efficiently. There are also several therapeutic approaches that have entered into clinical trials and shown considerable promise for decreasing the risk of CVD. In recent years, a variety of novel findings reveal the molecular mechanisms for the CTS and its role in the development of atherosclerosis, thereby providing novel insights into the understanding of whole-body cholesterol transport and metabolism. In this review, we summarize the latest advances in this area with an emphasis on the therapeutic potential of targeting the CTS in CVD patients.

High Fat Diet-Induced miR-122 Regulates Lipid Metabolism and Fat Deposition in Genetically Improved Farmed Tilapia (GIFT, Oreochromis niloticus) Liver

The liver is an important organ for the regulation of lipid metabolism. In genetically improved farmed tilapia (GIFT, Oreochromis niloticus), fat deposition in the liver occurs when they are fed high-lipid diets over a long term. This can affect their growth, meat quality, and disease resistance. MicroRNAs (miRNAs) are known to be crucial regulatory factors involved in lipid metabolism; however, the mechanism by which they regulate lipid deposition in GIFT remains unclear. Comparative miRNA expression profiling between GIFT fed a normal diet and those fed a high-lipid diet showed that miR-122 is closely related to lipid deposition. Using miR-122 as a candidate, we searched for a binding site for miR-122 in the 3'-untranslated region (UTR) of the stearoyl-CoA desaturase gene (SCD) using bioinformatics tools, and then confirmed its functionality using the luciferase reporter gene system. Then, the regulatory relationship between this miRNA and its target gene SCD was analyzed using real-time polymerase chain reaction (qRT-PCR) and western blotting analyses. Last, we investigated the effect of the loss of miR-122 expression on lipid metabolism in GIFT. The results showed that a sequence in the 3'-UTR region of SCD of GIFT was complementary to the miR-122 seed region, and there was a negative relationship between the expression of miRNA and SCD expression. Inhibition of miR-122 up-regulated SCD, increased the expression of fat synthesis-related genes, increased hepatic triglyceride and cholesterol contents, and promoted weight gain in fish. Our results showed that miR-122 targets SCD to mediate hepatic fat metabolism. These results provide new insights for the prevention and treatment of fatty liver disease in GIFT.

MicroRNA-296: a promising target in the pathogenesis of atherosclerosis?

Atherosclerosis has been recognized as an inflammatory disease involving the vascular wall. MicroRNAs are a group of small noncoding RNAs to regulate gene expression at the transcriptional level through mRNA degradation or translation repression. Recent studies suggest that miR-296 may play crucial roles in the regulation of angiogenesis, inflammatory response, cholesterol metabolism, hypertension, cellular proliferation and apoptosis. In this review, we primarily discussed the molecular targets of miR-296 involved in the development of atherosclerosis, which may provide a basis for future investigation and a better understanding of the biological functions of miR-296 in atherosclerosis.

MicroRNA-134 Promotes the Development of Atherosclerosis Via the ANGPTL4/LPL Pathway in Apolipoprotein E Knockout Mice

AIMS

Atherosclerosis is the most common cause of cardiovascular disease, such as myocardial infarction and stroke. Previous study revealed that microRNA (miR)-134 promotes lipid accumulation and proinflammatory cytokine secretion through angiopoietin-like 4 (ANGPTL4)/lipid lipoprotein (LPL) signaling in THP-1 macrophages.

METHODS

ApoE KO male mice on a C57BL/6 background were fed a high-fat/high-cholesterol Western diet, from 8 to 16 weeks of age. Mice were divided into four groups, and received a tail vein injection of miR-134 agomir, miR-134 antagomir, or one of the corresponding controls, respectively, once every 2 weeks after starting the Western diet. After 8 weeks we measured aortic atherosclerosis, LPL Activity, mRNA and protein levels of ANGPTL4 and LPL, LPL/ low-density lipoprotein receptor related protein 1 Complex Formation, proinflammatory cytokine secretion and lipid levels.

RESULTS

Despite this finding, the influence of miR-134 on atherosclerosis in vivo remains to be determined. Using the well-characterized mouse atherosclerosis model of apolipoprotein E knockout, we found that systemic delivery of miR-134 agomir markedly enhanced the atherosclerotic lesion size, together with a significant increase in proinflammatory cytokine secretion and peritoneal macrophages lipid contents. Moreover, overexpression of miR-134 decreased ANGPTL4 expression but increased LPL expression and activity in both aortic tissues and peritoneal macrophages, which was accompanied by increased formation of LPL/low-density lipoprotein receptor-related protein 1 complexes in peritoneal macrophages. However, an opposite effect was observed in response to miR-134 antagomir.

CONCLUSIONS

These findings suggest that miR-134 accelerates atherogenesis by promoting lipid accumulation and proinflammatory cytokine secretion via the ANGPTL4/LPL pathway. Therefore, targeting miR-134 may offer a promising strategy for the prevention and treatment of atherosclerotic cardiovascular disease.

Expression Profiles of Six Atherosclerosis-Associated microRNAs That Cluster in Patients with Hyperhomocysteinemia: A Clinical Study

The aim of this study is to discuss the hypothesis that expression of plasma atherosclerosis-associated microRNAs (miRNAs) in hyperhomocysteinemia (Hhcy) patients could predict the presence of atherosclerosis from different channels. Six plasma miRNAs (miR-145, miR-155, miR-222, miR-133, miR-217, and miR-30) selected for our study have been confirmed as critical gene regulators involved in atherosclerosis and can be steadily determined in plasma. Expression of the above six plasma circulating miRNAs revealed significant upregulation of two miRNAs (miR-133 and miR-217) and downregulation of three miRNAs (miR-145, miR-155, and miR-222). Six candidate miRNAs showed a significant correlation with homocysteine (Hcy) or lipid parameters. The results of this study indicated that miR-217 was further significantly upregulated in Hhcy + ATH groups than in normal control, Hhcy-, and atherosclerosis-alone (ATH) groups and it showed a significant negative correlation with Hcy and triglycerides. More specifically, miR-217 showed the most specific expression patterns in all patients with atherosclerosis (ATH and Hhcy + ATH groups), which may have been a diagnostic value for Hhcy complicated with atherosclerosis, and predicted the progress of atherosclerosis in Hhcy patients effectively.

H19 knockdown suppresses proliferation and induces apoptosis by regulating miR-148b/WNT/β-catenin in ox-LDL -stimulated vascular smooth muscle cells

Background

Long non-coding RNAs (lncRNAs) have been identified as critical regulators in the development of atherosclerosis (AS). Here, we focused on discussing roles and molecular mechanisms of lncRNA H19 in vascular smooth muscle cells (VSMCs) progression.

Methods

RT-qPCR assay was used to detect the expression patterns of H19 and miR-148b in clinical samples and cells. Cell proliferative ability was evaluated by CCK-8 and colony formation assays. Cell apoptotic capacity was assessed by apoptotic cell percentage and the caspase-3 activity. Bioinformatics analysis, luciferase and RNA immunoprecipitation (RIP) assays were employed to demonstrate cell percentage and the relationship among H19, miR-148b and wnt family member 1 (WNT1). Western blot assay was performed to determine expressions of proliferating cell nuclear antigen (PCNA), ki-67, Bax, Bcl-2, WNT1, β-catenin, C-myc and E-cadherin.

Results

The level of H19 was increased and miR-148b expression was decreased in human AS patient serums and oxidized low-density lipoprotein (ox-LDL)-stimulated human aorta vascular smooth muscle cells (HA-VSMCs). H19 knockdown suppressed proliferation and promoted apoptosis in HA-VSMCs following the treatment of ox-LDL. H19 inhibited miR-148b expression by direct interaction. Moreover, miR-148b inhibitor could reverse the effects of H19 depletion on proliferation and apoptosis in ox-LDL-stimulated HA-VSMCs. Further mechanical explorations showed that WNT1 was a target of miR-148b and H19 acted as a competing endogenous RNA (ceRNA) of miR-148b to enhance WNT1 expression. Furthermore, miR-148 inhibitor exerted its pro-proliferation and anti-apoptosis effects through activating WNT/β-catenin signaling in ox-LDL-stimulated HA-VSMCs.

Conclusion

H19 facilitated proliferation and inhibited apoptosis through modulating WNT/β-catenin signaling pathway via miR-148b in ox-LDL-stimulated HA-VSMCs, implicating the potential values of H19 in AS therapy.

miR-26a inhibits atherosclerosis progression by targeting TRPC3

Background

Atherosclerosis, a chronic multi-factorial vascular disease, has become a predominant cause of a variety of cardiovascular disorders. miR-26a was previously reported to be involved in atherosclerosis progression. However, the underlying mechanism of miR-26a in atherosclerosis remains to be further explained.

Methods

High-fat diet (HFD)-fed apolipoprotein E (apoE)^-/- mice and oxidized low-density lipoprotein (ox-LDL)-stimulated human aortic endothelial cells (HAECs) were established as in vivo and in vitro models of atherosclerosis. RT-qPCR and western blot analysis were performed to measure the expression of miR-26a and transient receptor potential canonical 3 (TRPC3), respectively. Binding between miR-26a and TRPC3 was predicted with bioinformatics software and verified using a dual luciferase reporter assay. The effects of miR-26a on the lipid accumulation, atherosclerotic lesion, and inflammatory response in HFD-fed apoE^-/- mice were investigated by a colorimetric enzymatic assay system, hematoxylin-eosin and oil-Red-O staining, and ELISA, respectively. Additionally, the effects of miR-26a or combined with TRPC3 on cell viability, apoptosis and the nuclear factor-kappa B (NF-κB) pathway in ox-LDL-stimulated HAECs were evaluated by MTT assay, TUNEL assay, and western blot, respectively.

Results

miR-26a was downregulated in HFD-fed apoE^-/- mice and ox-LDL-stimulated HAECs. miR-26a overexpression inhibited the pathogenesis of atherosclerosis by attenuating hyperlipidemia, atherosclerotic lesion and suppressing inflammatory response in HFD-fed apoE^-/- mice. Moreover, miR-26a overexpression suppressed inflammatory response and the NF-κB pathway, promoted cell viability and inhibited apoptosis in ox-LDL-stimulated HAECs. Additionally, TRPC3 was demonstrated to be a direct target of miR-26a. Enforced expression of TRPC3 reversed the effects of miR-26a on cell viability, apoptosis, and the NF-κB pathway in ox-LDL-treated HAECs.

Conclusions

miR-26a alleviated the development of atherosclerosis by regulating TRPC3, providing a potential target for atherosclerosis treatment.

MicroRNA-126 participates in lipid metabolism in mammary epithelial cells

Lipids are a major component of milk and are important for infant growth and development. MicroRNA-126 (miR-126) has previously been observed in mammary glands and adipocytes and is known to be involved in lipid metabolism during the process of atherosclerosis. However, it remains unknown whether miR-126 also participates in lipid metabolism in mammary luminal epithelial cells (MECs). In the current investigation, miR-126-3p inhibition stimulated lipid synthesis in MECs in part through increasing levels of the lipid synthesis enzymes FASN, ACSL1, and Insig1. Overexpression of miR-126-3p decreased lipid content in MECs with a reduction in FASN and Insig1. Furthermore, the expression of miR-126-3p was diminished by the steroid hormones estradiol and progesterone with a subsequent elevation of lipid formation in MECs. We also noted that miR-126-3p was expressed differentially at various stages of murine mammary gland development, exhibiting a negative correlation with FASN. Together these findings suggest that miR-126-3 might be involved in lipid metabolism in mammary gland.