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TP53-induced glycolysis and apoptosis regulator (TIGAR) is now characterized as a fructose-2,6-bisphosphatase to reduce glycolysis and protect against oxidative stress. Recent studies have demonstrated that TIGAR is associated with cardiovascular disease. However, little is known about its role in atherosclerogenesis. In this study, we aimed to investigate the effect of TIGAR on atherosclerosis and explore the underlying molecular mechanism. The Gene Expression Omnibus (GEO) datasets were used to analyze the differential expression of relative proteins. THP-1-derived macrophages were used as an in vitro model and apolipoprotein E-deficient (Apoe −/−) mice were used as an in vivo model. [3H] labeled cholesterol was used to assess the capacity of cholesterol efflux and reverse cholesterol transport (RCT). Both qPCR and Western blot were used to evaluate the mRNA and protein expression, respectively. Lentiviral vectors were used to disturb the expression of TIGAR in vitro and in vivo. Oil Red O, hematoxylin-eosin, and Masson staining were performed to evaluate atherosclerotic plaques in Apoe −/− mice fed a Western diet. Conventional assay kits were used to measure the levels of reactive oxygen species (ROS), plasma lipid profiles and 27-hydroxycholesterol (27-HC). Our results showed that TIGAR is increased upon the formation of macrophage foam cells and atherosclerosis. TIGAR knockdown markedly promoted lipid accumulation in macrophages. Silencing of TIGAR impaired cholesterol efflux and down-regulated the expression of ATP-binding cassette transporter A1 (ABCA1) and ABCG1 by interfering with liver X receptor α (LXRα) expression and activity, but did not influence cholesterol uptake by macrophages. Additionally, this inhibitory effect of TIGAR deficiency on cholesterol metabolism was mediated through the ROS/CYP27A1 pathway. In vivo experiments revealed that TIGAR deficiency decreased the levels of ABCA1 and ABCG1 in plaques and aorta and impaired the capacity of RCT, thereby leading to the progression of atherosclerosis in Apoe −/− mice. TIGAR mitigates the development of atherosclerosis by up-regulating ABCA1 and ABCG1 expression via the ROS/CYP27A1/LXRα pathway. [Display omitted] • TIGAR is involved in macrophage foam cells formation and atherosclerosis development. • TIGAR promotes ABCA1-and ABCG1-dependent cholesterol efflux, but does not influence cholesterol uptake in macrophages. • TIGAR increases ABCA1 and ABCG1 expression by reducing ROS and activating CYP27A1/LXRα pathway. • TIGAR facilitatesreverse cholesterol transport (RCT) and mitigates the development of atherosclerosis in Apoe −/− mice. [ABSTRACT FROM AUTHOR]

Background and aims Recent studies have suggested that heat shock protein 70 (HSP70) may play critical roles in cardiovascular disease. However, the effects of HSP70 on the development of atherosclerosis in apoE −/− mice remain largely unknown. This study was to investigate the role and potential mechanism of HSP70 in atherosclerosis. Methods HSP70 was overexpressed in apoE −/− mice and THP-1-derived macrophages with lentiviral vectors. Oil Red O, hematoxylin-eosin, and Masson staining were performed to evaluate atherosclerotic plaque in apoE −/− mice fed the Western type diet. Moreover, immunostaining was employed to detect the expression of relative proteins in aortic sinus. Reporter gene and chromatin immunoprecipitation were performed to analyze the effect of Elk-1 on the promoter activity of ABCA1 and ABCG1; [ 3 H] labeled cholesterol was used to assess the capacity of cholesterol efflux and reverse cholesterol transport (RCT). Results Our results showed that HSP70 increased lipid accumulation in arteries and promoted the formation of atherosclerotic lesion. The capacity of cholesterol efflux was reduced in peritoneal macrophages isolated from HSP70-overexpressed apoE −/− mice. The levels of ABCA1 and ABCG1 expression were also reduced in the peritoneal macrophages and the aorta from apoE −/− mice in response to HSP70. The c-Jun N-terminal kinase (JNK) and ETS transcription factor (Elk-1) played a critical role in HSP70-induced downregulation ABCA1 and ABCG1. Further, HSP70 reduced RCT from macrophages to plasma, liver, and feces in apoE −/− mice. Conclusions HSP70 promotes the progression of atherosclerosis in apoE −/− mice by suppressing the expression of ABCA1 and ABCG1 through the JNK/Elk-1 pathway. [ABSTRACT FROM AUTHOR]

The purpose of this study was to explore the role of long noncoding RNA (lncRNA) prostate cancer antigen 3 (PCA3) in atherosclerosis and the underlying mechanism. The Gene Expression Omnibus (GEO) datasets were used to divide differentially expressed lncRNAs, microRNAs (miRNAs), and mRNAs. The expression of PCA3, miR-140-5p, RFX7 and ABCA1 were determined by qPCR or Western blot in ox-LDL-treated macrophages. Macrophage lipid accumulation s was evaluated using the Oil Red O staining and high-performance liquid chromatography. Target relationships among PCA3, miR-140-5p, RFX7, and ABCA1 promoter area were validated via dual-luciferase reporter gene assay or chromatin immunoprecipitation assay. The apoE−/− mouse model in vivo was designed to evaluate the effect of PCA3 on the reverse cholesterol transport (RCT) and atherosclerosis. PCA3 was down-regulated in foam cells, whereas miR-140-5p was highly expressed. Overexpression of PCA3 promoted ABCA1-mediated cholesterol efflux and reduced lipid accumulation in macrophages. Besides, RFX7 bound to the ABCA1 promoter and increased ABCA1 expression. Targeted relationships and interactions on the expression between miR-140-5p and PCA3 or RFX7 were elucidated. PCA3 up-regulated ABCA1 expression by binding to miR-140-5p to up-regulate RFX7 and ABCA1 expression in macrophages. PCA3 promoted RCT and impeded the progression of atherosclerosis by sponging miR-140-5p in apoE−/− mice. Meanwhile, miR-140-5p also inhibit ABCA1 expression via downregulation of RFX7 to impede RCT and aggravate atherosclerosis. lncRNA PCA3 promotes ABCA1-mediated cholesterol efflux to inhibit atherosclerosis through sponging miR-140-5p and up-regulating RFX7. • LncRNA PCA3 facilitates RCT and mitigates the development of atherosclerosis in apoE−/− mice. • LncRNA PCA3 promotes ABCA1-dependent cholesterol efflux and reduced the lipid accumulation in macrophages-derived foam cells. • RFX7 is the new transcription factor to bind with ABCA1 promoter. • TIGAR as the ceRNA against miR-140-5p to upregulate RFX7 and promote ABCA1 expression. [ABSTRACT FROM AUTHOR]

It was reported that puerarin decreases the total cholesterol, low-density lipoprotein cholesterol (LDL-C), triglyceride (TG) and increases high-density lipoprotein cholesterol (HDL-C) level, but the underlying mechanism is unclear. This study was designed to determine whether puerarin decreased lipid accumulation via up-regulation of ABCA1-mediated cholesterol efflux in THP-1 macrophage-derived foam cells. Our results showed that puerarin significantly promoted the expression of ATP-binding cassette transporter A1 (ABCA1) mRNA and protein via the AMP-activated protein kinase (AMPK)-peroxisome proliferator-activated receptor gamma (PPARγ)-liver X receptor-alpha (LXR-α) pathway and decreased cellular lipid accumulation in human THP-1 macrophage-derived foam cells. The miR-7 directly targeted 3′ untranslated region of STK11 (Serine/Threonine Kinase 11), which activated the AMPK pathway. Transfection with miR-7 mimic significantly reduced STK11 expression in puerarin-treated macrophages, decreased the phosphorylation of AMPK, down-regulated the expression of the PPARγ-LXR-α-ABCA1 expression. Additionally, treatment with miR-7 decreased cholesterol efflux and increased cholesterol levels in THP-1 macrophage-derived foam cells. Our study demonstrates that puerarin promotes ABCA1-mediated cholesterol efflux and decreases intracellular cholesterol levels through the pathway involving miR-7, STK11, and the AMPK-PPARγ-LXR-α-ABCA1 cascade. [ABSTRACT FROM AUTHOR]

Rationale Previous studies have shown that apolipoprotein-1 (apoA-1) binding protein (AIBP) is highly associated with the regulation of apoA-1 metabolism, suggesting its role in the treatment of atherosclerosis. However, how AIBP regulates foam cell formation remains largely unexplored. Objective To investigate the mechanisms underlying AIBP inhibition of foam cell formation from macrophages. Methods and results THP-1-derived macrophages were incubated without or with apoA-1 and AIBP, followed by assessing the formation of foam cells and the potential mechanisms. Our results showed that AIBP and apoA-1 enhanced cholesterol efflux, altered the levels of cellular free cholesterol and cholesterol ester and prevented lipid accumulation so as to reduce the formation of foam cells. Meanwhile, lack of AIBP 115–123 amino acids resulted in the loss of AIBP binding to apoA-1. Moreover, our chemiluminescent analysis showed that AIBP promoted biotin-labeled apoA-1 binding to macrophages. Besides with AIBP, more apoA-1 bound to ABCA1, a key transporter responsible for cholesterol efflux to apoA-1, as indicated by our co-immunoprecipitation assay. Our results also showed that AIBP did not regulate ABCA1 mRNA expression, but stabilized its protein from CSN2-mediated degradation. Conclusions AIBP promotes apoA-1 binding to ABCA1 on the cell membrane of macrophages and prevents ABCA1 protein from CSN2-mediated degradation so as to prevent foam cell formation. AIBP 115–123 amino acids is at least partially responsible for its binding to apoA-1. [ABSTRACT FROM AUTHOR]

This study was designed to evaluate whether CSE/H 2 S system, which is regulated by miR-216a, regulated ABCA1-mediated cholesterol efflux and cholesterol contents in THP-1 macrophages-derived foam cells. Our qPCR and western blotting results showed that CSE/H 2 S significantly up-regulated the expression of ATP-binding cassette transporter A1 (ABCA1) mRNA and protein via PI3K/AKT pathway in foam cells derived from human THP-1 macrophages. The miR-216a directly targeted 3′ untranslated region of CSE. It significantly reduced CSE and ABCA1 expression, and also decreased the phosphorylation of PI3K and AKT. Additionally, cholesterol efflux decreased, and cholesterol levels increased in THP-1 macrophage-derived foam cells in response to treatment with miR-216a. Our study demonstrates that CSE/H 2 S system is regulated by miR-216a, and regulates ABCA1-mediated cholesterol efflux and cholesterol levels through the PI3K/AKT pathway. [ABSTRACT FROM AUTHOR]

Myocardin (MYOCD) plays an important role in cardiovascular disease. However, its underlying impact on atherosclerosis remains to be elucidated. ATP binding cassette transporter A1 (ABCA1), a key membrane-associated lipid transporter which maintains intracellular lipid homeostasis, has a protective function in atherosclerosis progress. The purpose of this study was to investigate whether and how the effect of MYOCD on atherosclerosis is associated with ABCA1 in vascular smooth muscle cells (VSMCs). We found both MYOCD and ABCA1 expression were dramatically decreased in atherosclerotic patient aortas compared to control. MYOCD knockdown inhibited ABCA1 expression in human aortic vascular smooth muscle cells (HAVSMCs), leading to reduced cholesterol efflux and increased intracellular cholesterol contents. MYOCD overexpression exerted the opposite effect. Mechanistically, MYOCD regulates ABCA1 expression in an SRF-dependent manner. Consistently, apolipoprotein E-deficient mice treated with MYOCD shRNA developed more plaques in the aortic sinus, which is associated with reduced ABCA1 expression, increased cholesterol retention in the aorta, and decreased high-density lipoprotein cholesterol levels in the plasma. Our data suggest that MYOCD deficiency exacerbates atherosclerosis by downregulating ABCA1 dependent cholesterol efflux from VSMCs, thereby providing a novel strategy for the therapeutic treatment of atherosclerotic cardiovascular disease. • MYOCD and ABCA1 expressions are decreased in aortic atherosclerosis patients. • MYOCD regulates ABCA1 expression in an SRF-dependent manner in VSMCs. • MYOCD suppression exacerbates atherosclerosis in rodent model. [ABSTRACT FROM AUTHOR]

Fargesin mainly functions in the improvement of lipid metabolism and the inhibition of inflammation, but the role of fargesin in atherogenesis and the molecular mechanisms have not been defined. We aimed to explore if and how fargesin affects atherosclerosis by regulating lipid metabolism and inflammatory response. ApoE−/− mice were fed a high-fat diet to form atherosclerotic plaques and then administrated with fargesin or saline via gavage. Oil Red O, HE and Masson staining were performed to assess atherosclerostic plaques in apoE−/− mice. [3H] labeled cholesterol was used to detect cholesterol efflux and reverse cholesterol transport (RCT) efficiency. Enzymatic methods were performed to analyze plasma lipid profile in apoE−/− mice. Immunohistochemistry was used to analyze macrophage infiltration. THP-1-derived macrophages were incubated with fargesin or not. Both Western blot and qRT-PCR were applied to detect target gene expression. Oil Red O staining was applied to examine lipid accumulation in THP-1-derived macrophages. ELISA and qRT-PCR were used to examine the levels of inflammatory mediotors. We found that fargesin reduced atherosclerotic lesions by elevating efficiency of RCT and decreasing inflammatory response via upregulation of ABCA1 and ABCG1 expression in apoE−/− mice. Further, fargesin reduced lipid accumulation in THP-1-derived macrophages. Besides, fargesin increased phosphorylation of CEBPα in Ser21 and then upregulated LXRα, ABCA1 and ABCG1 expression in THP-1-derived macrophages. In addition, fargesin could reduce ox-LDL-induced inflammatory response by inactivation of the TLR4/NF-κB pathway. These results suggest that fargesin inhibits atherosclerosis by promoting RCT process and reducing inflammatory response via CEBPαS21/LXRα and TLR4/NF-κB pathways, respectively. • Fargesin reduces atherogenesis in apoE−/− mice. • Fargesin promotes RCT via CEBPαS21/LXRα pathway. • Fargesin inhibits inflammation via TLR4/NF-κB pathway. [ABSTRACT FROM AUTHOR]

Angiopoietin-1 (Ang-1), a secreted protein, mainly regulates angiogenesis. Ang-1 has been shown to promote the development of atherosclerosis, whereas little is known about its effects on lipid metabolism and inflammation in this process. Ang-1 was transfected into ApoE−/− mice via lentiviral vector or incubated with THP-1 derived macrophages. Oil red O and HE staining were performed to measure the size of atherosclerotic plaques in ApoE−/− mice. Immunofluorescence was employed to show the expression of target proteins in aorta. [3H] labeled cholesterol was performed to examine the efficiency of cholesterol efflux and reverse cholesterol transport (RCT) both in vivo and vitro. Western blot and qPCR were used to quantify target proteins both in vivo and vitro. ELISA detected the levels of pro-inflammatory cytokines in mouse peritoneal macrophage. Our data showed that Ang-1 augmented atherosclerotic plaques formation and inhibited cholesterol efflux. The binding of Ang-1 to Tie2 resulted in downregulation of LXRα, ABCA1 and ABCG1 expression via inhibiting the translocation of TFE3 into nucleus. In addition, Ang-1 decreased serum HDL-C levels and reduced reverse cholesterol transport (RCT) in ApoE−/− mice. Furthermore, Ang-1 induced lipid accumulation followed by increasing TNF-α, IL-6, IL-1β，and MCP-1 produced by MPMs, as well as inducing M1 phenotype macrophage marker iNOS and CD86 expression in aorta of ApoE−/− mice. Ang-1 has an adverse effect on cholesterol efflux by decreasing the expression of ABCA1 and ABCG1 via Tie2/TFE3/LXRα pathway, thereby promoting inflammation and accelerating atherosclerosis progression. • Angiopoietin-1 inhibits reverse cholesterol transport via Tie2/LXRα/TFE3/pathway • Angiopoietin-1 promotes vascular inflammation • Angiopoietin-1 accelerates atherogenesis [ABSTRACT FROM AUTHOR]

Previous studies suggest that IL-8 has an important role in the regulation of cholesterol efflux, but whether miRNAs are involved in this process is still unknown. The purpose of this study is to explore whether IL-8 promotes cholesterol accumulation by enhancing miR-183 expression in macrophages and its underlying mechanism. Treatment of THP-1 macrophage-derived foam cells with IL-8 decreased ABCA1 expression and cholesterol efflux. Using bioinformatics analyses and dual-luciferase reporter assays, we found that miR-183 was highly conserved during evolution and directly inhibited ABCA1 protein and mRNA expression by targeting ABCA1 3′UTR. MiR-183 directly regulated endogenous ABCA1 expression levels. Furthermore, IL-8 enhanced the expression of miR-183 and decrease ABCA1 expression. Cholesterol transport assays confirmed that IL-8 dramatically inhibited apolipoprotein AI-mediated ABCA1-dependent cholesterol efflux by increasing miR-183 expression. In contrast, treatment with anti-IL-8 antibody reversed these effects. IL-8 enhances the expression of miR-183, which then inhibits ABCA1 expression and cholesterol efflux. Our studies suggest that the IL-8-miR-183-ABCA1 axis may play an intermediary role in the development of atherosclerosis. [ABSTRACT FROM AUTHOR]