miR-497 accelerates oxidized low-density lipoprotein-induced lipid accumulation in macrophages by repressing the expression of apelin

The dysregulation of plasma miR-497/FGF23 axis, and its association with clinical characteristics and major adverse cardiovascular event in female premature acute coronary syndrome patients

AIM

MicroRNA-497 (miR-497) directly targets fibroblast growth factor 23 (FGF23) to participate in the pathology of acute coronary syndrome (ACS) by regulating atherosclerosis, inflammatory response, lipid metabolism, etc. This study intended to investigate the dysregulation of the miR-497/FGF23 axis, and its association with the major adverse cardiovascular event (MACE) in female premature ACS.

METHODS

MiR-497 and FGF23 from plasma samples were detected by RT-qPCR and ELISA in 979 newly diagnosed female premature ACS patients and 100 healthy controls (HCs). MACE was recorded during follow-up (median: 27.0, range: 1.0-54.0 months) in female premature ACS patients.

RESULTS

MiR-497/FGF23 axis was reduced in female premature ACS patients versus HCs [median (interquartile range): 0.7 (0.1-1.2) versus 1.9 (1.1-3.4)] (P < 0.001). Meanwhile, miR-497 negatively correlated with FGF23 in femal e premature ACS patients (P < 0.001), but not in HCs (P = 0.157). In female premature ACS patients, the miR-497/FGF23 axis was negatively associated with serum creatinine (P < 0.001), serum uric acid (P = 0.003), high-sensitivity C-reactive protein (P < 0.001), total cholesterol (P = 0.031), and low-density lipoprotein cholesterol (P = 0.003). The 1-year, 2-year, 3-year, and 4-year accumulating MACE rate was 2.9%, 8.6%, 16.7%, and 26.0%, respectively. Interestingly, a high level of miR-497/FGF23 axis predicted decreased accumulating MACE risk (P < 0.001). After adjustment by multivariate Cox's regression analysis, the high miR-497/FGF23 axis (hazard ratio (HR) = 0.005, P = 0.001) independently correlated with reduced accumulating MACE risk.

CONCLUSION

The plasma miR-497/FGF23 axis represents favorable kidney function, decreased inflammation, and reduced lipid level; meanwhile, this axis possesses prognostic value in predicting decreased accumulating MACE risk in female premature ACS patients.

Polarization of rheumatoid macrophages is regulated by the CDKN2B-AS1/ MIR497/TXNIP axis

The polarization of macrophages plays a critical role in the pathophysiology of rheumatoid arthritis. The macrophages can have pro-inflammatory M1 polarization and various types of alternative anti-inflammatory M2 polarization. Our preliminary results showed that the CDKN2B-AS1/MIR497/TXNIP axis might regulate macrophages of rheumatoid arthritis patients. Therefore, we hypothesized that this axis regulated the polarization of rheumatoid macrophages. Flow cytometry was used to determine the surface polarization markers in M1 or M2 macrophages from healthy donors and rheumatoid arthritis patients. The QPCR and Western Blotting were used to compare the expression of the CDKN2B-AS1/MIR497/TXNIP axis in these macrophages. We Knocked down and overexpressed the axis in the macrophage cell line MD to test its roles in macrophage polarization. Compared to cells from healthy donors, cells from rheumatoid arthritis patients expressed higher levels of CD40 and CD80 and lower levels of CD16, CD163, CD206, and CD200R after polarization, they also expressed higher CDKN2B-AS1, lower MIR497, and higher TXNIP. In macrophages from healthy donors, there was no correlation among CDKN2B-AS1, MIR497, and TXNIP. But in macrophages from patients, there were significant correlations. The CDKN2B-AS1 knockdown, MIR497 mimics suppressed the M1 polarization but promoted the M2 polarization in MD cells, while the MIR497 knockdown and the TXNIP overexpression did the opposite. This study demonstrated that elevated CDKN2B-AS1 in macrophages promotes the M1 polarization and inhibited the M2 polarization of macrophages by the CDKN2B-AS1/ MIR497/TXNIP axis.

The Role of Serum miR-497 on the Predictive Index of Early Diagnosis and Poor Prognosis of Atherosclerosis Cerebral Infarction

Background:

Serum miR-497 can be used as a predictive index of the early diagnosis and poor prognosis of atherosclerosis cerebral infarction (ATCI).

Methods:

Overall, 135 ATCI patients, treated in The Second Affiliated Hospital of Nantong University, Nantong 226001, P.R.China from Apr 2012 to Jan 2015, were included in ATCI group. Whereas, 77 patients with non-atherosclerosis cerebral infarction were put in the control group. RT-qPCR was performed for detecting serum miR-497 expression, whose relationship with the patients’ clinicopathological parameters was analyzed. Receiver operating characteristic (ROC) curves were plotted to evaluate values of serum miR-497 for diagnosing ATCI patients and their 3-year and 5-year overall survival rates (OSRs). Cox regression analysis was conducted on prognostic factors of ATCI patients.

Results:

miR-497 remarkably rose in the serum of ATCI patients, and was correlated with histories of hypertension, smoking and diabetes mellitus (DM). Its areas under curves (AUCs) for diagnosing these pathological parameters were 0.803, 0.817 and 0.819, respectively. Its expression was higher in the serum of the patients with recurrence and poor prognoses. Its AUCs for predicting the two conditions were 0.924 and 0.937, respectively. The 3- and 5-year OSRs of patients with low expression were remarkably higher than those of patients with high expression.

Conclusion:

miR-497 and histories of hypertension, smoking and DM were independent prognostic factors affecting the 3-year OSR of ATCI patients. miR-497 expression rises in ATCI patients, so this miR is expected to become a serum diagnostic marker for ATCI.

Foam Cells as Therapeutic Targets in Atherosclerosis with a Focus on the Regulatory Roles of Non-Coding RNAs

Atherosclerosis is a major cause of human cardiovascular disease, which is the leading cause of mortality around the world. Various physiological and pathological processes are involved, including chronic inflammation, dysregulation of lipid metabolism, development of an environment characterized by oxidative stress and improper immune responses. Accordingly, the expansion of novel targets for the treatment of atherosclerosis is necessary. In this study, we focus on the role of foam cells in the development of atherosclerosis. The specific therapeutic goals associated with each stage in the formation of foam cells and the development of atherosclerosis will be considered. Processing and metabolism of cholesterol in the macrophage is one of the main steps in foam cell formation. Cholesterol processing involves lipid uptake, cholesterol esterification and cholesterol efflux, which ultimately leads to cholesterol equilibrium in the macrophage. Recently, many preclinical studies have appeared concerning the role of non-encoding RNAs in the formation of atherosclerotic lesions. Non-encoding RNAs, especially microRNAs, are considered regulators of lipid metabolism by affecting the expression of genes involved in the uptake (e.g., CD36 and LOX1) esterification (ACAT1) and efflux (ABCA1, ABCG1) of cholesterol. They are also able to regulate inflammatory pathways, produce cytokines and mediate foam cell apoptosis. We have reviewed important preclinical evidence of their therapeutic targeting in atherosclerosis, with a special focus on foam cell formation.

miR-188-3p Inhibits Vascular Smooth Muscle Cell Proliferation and Migration by Targeting Fibroblast Growth Factor 1 (FGF1)

Background

As one of the crucial causes leading to cardiovascular disease, atherosclerosis (AS) develops in association with the dysfunction of vascular smooth muscle cells (VSMCs). However, the associated mechanism of the proliferation and migration in VSMCs requires further elucidation.

Material/Methods

Human VSMCs and ApoE-knockout (ApoE^−/−) mice were used to establish AS cell and animal models, respectively. Expression levels of miR-188-3p and fibroblast growth factor 1 (FGF1) mRNA were detected using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Western blot was used to assess FGF1 protein expression. The proliferation, migration, and apoptosis of the cells were determined using MTT, BrdU, and Transwell assays, as well as flow cytometry analysis. The interaction between miR-188-3p and FGF1 was validated using dual-luciferase reporter gene assay, qRT-PCR, and Western blot analysis.

Results

MiR-188-3p was found to be significantly decreased in the serum of AS patients and ApoE^−/− mice as well as VSMCs of ApoE^−/− mice and human VSMCs treated with oxidized low-density lipoprotein. MiR-188-3p repressed the proliferation and migration of VSMCs but promoted apoptosis of VSMCs. The binding site between miR-188-3p and 3′ untranslated region (3′-UTR) of FGF1 was identified, and FGF1 was verified as a target gene of miR-188-3p. Restoration of FGF1 reversed the effects of miR-188-3p on VSMCs.

Conclusions

MiR-188-3p suppresses the proliferation and migration of VSMCs and induces their apoptosis through targeting FGF1.

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.

Functional lncRNA-miRNA-mRNA networks in rabbit carotid atherosclerosis

Atherosclerosis is one of the most common clinical cardiovascular disorders. Accumulating evidence indicates that lncRNAs exert critical functions in atherosclerosis; however, their functional roles and regulatory mechanisms remain unclear. In this study, we induced atherosclerotic plaques in three rabbit carotid arteries through an atherogenic diet and balloon injury; three age-matched rabbits were fed normal chow and served as controls. We thoroughly investigated the RNA (mRNA, lncRNA and miRNA) expression profiles in atherosclerotic rabbit carotid models with deep RNA sequencing. We identified several significantly differentially expressed RNAs. The corresponding lncRNA-miRNA-mRNA network was constructed, and the significantly dysregulated network was selected. Furthermore, Gene Ontology and  Kyoto Encyclopedia of Genes and Genomes analyses indicated that the mRNAs in the network were involved in leukocyte activation, cell proliferation, cell adhesion molecules and cytokine-cytokine receptor interaction. After rigorous screening, we obtained a differentially expressed lncRNA-miRNA-mRNA interaction network associated with atherosclerosis. In the network, XLOC_054118 and XLOC_030217 upregulate the CHI3L1, SOAT, CTSB and CAPG genes by competitively binding to the miRNA ocu-miR-96-5p. XLOC_062719 and XLOC_063297 upregulate CTSS, CTSB and EDNRA genes by competitively binding to the miRNA ocu-miR-185-5p.

1, 25-Dihydroxyvitamin D3 activates Apelin/APJ system and inhibits the production of adhesion molecules and inflammatory mediators in LPS-activated RAW264.7 cells

BACKGROUND

1, 25-Dihydroxyvitamin D3 (1, 25(OH)2D3), an active form of vitamin D3, plays a crucial role in the mitigation of inflammation damage. Recent studies have revealed that apelin and its receptor (apelin/APJ system) could significantly ameliorate LPS-induced inflammation-response. This investigation aimed to appraise the effects of 1, 25(OH)2D3 on the apelin/APJ system and production of adhesion molecules and inflammatory mediators in LPS-activated RAW264.7 macrophage cells.

METHODS

Murine RAW264.7 cells were pretreated with 1, 25(OH)2D3, followed stimulation with LPS (1 μg/mL) for 24 h. The effect of 1, 25(OH)2D3 on LPS-induced cell injury was determined by MTT assay, whereas, enzyme-linked immunosorbent assay (ELISA), qPCR and western blotting were used to evaluate cytokine production and apelin/APJ system expression. Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) protein expression were measured by flow cytometry.

RESULTS

The levels of IL-1β, IL-6, and TNF-α cytokines were significantly increased by incubation with LPS. LPS also increased the protein expression of adhesion molecules, including VCAM-1 and ICAM-1. However, pretreatment with 1, 25(OH)2D3 markedly inhibited LPS-induced production of inflammatory cytokines and adhesion molecules. Moreover, we found that 1, 25(OH)2D3 could induced the apelin/APJ system expression. Further experiments demonstrated the significant increase of apelin/APJ system expression at both the protein and mRNA levels in LPS-activated cells when pretreated with 1, 25(OH)2D3.

CONCLUSION

Taken together, our results indicated that 1, 25(OH)2D3 confers an anti-inflammatory effect through a likely mechanism involving a reduction in pro-inflammatory mediators and adhesion molecules via up-regulation of the apelin/APJ system in RAW264.7 cells.

The cross-talk between adipokines and miRNAs in health and obesity-mediated diseases

BACKGROUND

Multiple studies have revealed a direct correlation between obesity and the development of multiple comorbidities, including metabolic diseases, cardiovascular disorders, chronic inflammatory disease, and cancers. However, the molecular mechanism underlying the link between obesity and the progression of these diseases is not completely understood. Adipokines are factors that are secreted by adipocytes and play a key role in whole body homeostasis. Collaboratively, miRNAs are suggested to have key functions in the development of obesity and obesity-related disorders. Based on recently emerging evidence, obesity leads to the dysregulation of both adipokines and obesity-related miRNAs. In the present study, we described the correlations between obesity and its related diseases that are mediated by the mutual regulatory effects of adipokines and miRNAs.

METHODS

We reviewed current knowledge of the modulatory effects of adipokines on miRNAs activity and their relevant functions in pathological conditions and vice versa.

RESULTS

Our research reveals the ability of adipokines and miRNAs to control the expression and activity of the other class of molecules, and their effects on obesity-related diseases.

CONCLUSIONS

This study may help researchers develop a roadmap for future investigations and provide opportunities to develop new therapeutic and diagnostic methods for treating obesity-related diseases.

APLN/APJ pathway: The key regulator of macrophage functions

Macrophages play key roles during cardiovascular diseases (CVD) and their related complications. Apelin (APLN) is a key molecule, whose roles during CVD have been documented previously. Therefore, it has been hypothesized that APLN may perform its roles via modulation of macrophages. Additionally, due to the widespread distribution of the CVD, more effective therapeutic strategies need to be developed to overcome the related complications. This review article collected recent information regarding the roles of APLN on the macrophages and discusses its potential chance to be a target for molecular/cellular therapy of APLN and the APLN treated macrophages for CVD.

MiR-590 Inhibits Endothelial Cell Apoptosis by Inactivating the TLR4/NF-κB Pathway in Atherosclerosis

PURPOSE

Previous study has well documented the anti-apoptotic effects of miR-590 on oxidized low-density lipoprotein (ox-LDL)-treated endothelial cells (ECs). However, the mechanism underlying the anti-apoptotic effects of miR-590 in ox-LDL-treated ECs remains to be further addressed.

MATERIALS AND METHODS

ApoE^-/- mice fed with a high-fat diet (HFD) and human aortic endothelial cells (HAECs) treated with ox-LDL were used as in vivo and in vitro models of atherosclerosis. The expressions of miR-590 and toll-like receptor 4 (TLR4) were detected by quantitative real-time PCR and Western blot, respectively. Atherosclerotic lesion analysis was performed using Evans blue and hematoxylin-eosin staining. Cell proliferation was assessed by MTT assay. Apoptosis was examined using flow cytometry analysis and Western blot analysis of Cleaved poly (ADP-ribose) polymerase (PARP) and Cleaved Caspase-3 levels. The effect of miR-590 on TLR4/nuclear factor kappa B (NF-κB) pathway was evaluated by Western blot. Binding between miR-590 and TLR4 was confirmed by luciferase reporter assay and Western blot.

RESULTS

miR-590 was downregulated in the aorta tissues from HFD-fed apoE^-/- mice and ox-LDL-treated HAECs. miR-590 overexpression inhibited atherosclerotic lesion in HFD-induced apoE^-/- mice and promoted proliferation and inhibited apoptosis of ox-LDL-treated HAECs. Additionally, TLR4 was identified as a direct target of miR-590 in ox-LDL-treated HAECs. Moreover, anti-miR-590 reversed TLR4 knockdown-mediated promotion of cell proliferation and suppression of apoptosis in ox-LDL-treated HAECs. miR-590 overexpression suppressed the TLR4/NF-κB pathway, and inhibition of the TLR4/NF-κB pathway promoted cell proliferation and impeded apoptosis in ox-LDL-treated HAECs.

CONCLUSION

miR-590 promoted proliferation and blocked ox-LDL-induced apoptosis in HAECs through inhibition of the TLR4/NF-κB pathway.

Dysregulation of cardiac lipid parameters in high-fat high-cholesterol diet-induced rat model

Background

Lipid dysregulation is a classical risk factor for cardiovascular disease (CVD), yet scanty evidence existed regarding cardiac lipid metabolism that is directly related to heart damage. Recently, the relationship between dyslipidemia and pro-inflammatory insults has led to further understanding on the CVD-predisposing effects of dyslipidemia. The aims of the present study were to investigate whether high-fat high-cholesterol (HFHC) diet-induced hyperlipidemia would cause heart damage and to study the potential role of local cardiac lipid dysregulation in the occurrence of cellular injury.

Methods

Male Sprague–Dawley rats were divided into normal chow or HFHC diet groups, and sacrificed after 2 or 4 weeks, respectively. Lipid peroxidation marker level was measured. Lipid parameters in the rat hearts were detected. Cardiac damage was evaluated.

Results

HFHC diet increased serum levels of cholesterol and free fatty acids (FFAs) and led to systemic oxidative stress and pro-inflammatory status. Cardiac lipid dysregulation, which was characterized by elevated levels of cholesterol and adipocyte (A)- and heart (H)-fatty acid binding proteins (FABPs), occurred after HFHC diet for 4 weeks. Cardiac damage was further evident with elevated circulating H-FABP levels, increased cardiac interstitial fibrosis and the loss of troponin I.

Conclusion

Our data demonstrated that HFHC diet led to systemic and cardiac lipid dysregulation, accompanied by systemic oxidative and pro-inflammatory stresses, and these may finally cooperate to cause a series of pathological changes of the heart tissue. Our findings suggest that maintenance of lipid regulation may be essential in the prevention of heart damage.

Usefulness of the Adipokines as Biomarkers of Ischemic Cardiac Dysfunction

Cardiovascular disease is the leading cause of death among both women and men, but there is still a great percentage of misdiagnosis and lack of clearly defined criteria. Advances in biomolecular science have proven the crucial role of inflammation and, more importantly, the role of adipokines in mediating all stages of coronary artery disease. It has also been suggested that regional fat deposits, more precisely from thoracic region, have a major influence on the development of coronary artery disease by creating a local proatherogenic environment. The immune system closely interacts with metabolic risk factors to initiate, promote, and further aggravate the atherosclerotic lesions on the arterial wall all with the "help" of adipokines. So nowadays, research extensively focuses on uncovering biomarkers that would provide an increased chance of detecting subclinical cardiac distress and also add a consistent value to current guideline-imposed risk criteria.