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Recent studies have demonstrated that commercially available lipid-lowering drugs cause various side effects; therefore, searching for anti-hyperlipidaemic compounds with lower toxicity is a research hotspot. This study was designed to investigate whether the marine-derived compound, 5-hydroxy-3-methoxy-5-methyl-4-butylfuran-2(5H)-one, has an anti-hyperlipidaemic activity, and the potential underlying mechanism in vitro. Results showed that the furanone had weaker cytotoxicity compared to positive control drugs. In RAW 264.7 cells, the furanone significantly lowered ox-LDL-induced lipid accumulation (~50%), and its triglyceride (TG)-lowering effect was greater than that of liver X receptor (LXR) agonist T0901317. In addition, it significantly elevated the protein levels of peroxisome proliferator-activated receptors (PPARα) and ATP-binding cassette (ABC) transporters, which could be partially inhibited by LXR antagonists, GSK2033 and SR9243. In HepG2 cells, it significantly decreased oleic acid-induced lipid accumulation, enhanced the protein levels of low-density lipoprotein receptor (LDLR), ABCG5, ABCG8 and PPARα, and reduced the expression of sterol regulatory element-binding protein 2 (~32%). PPARα antagonists, GW6471 and MK886, could significantly inhibit the furanone-induced lipid-lowering effect. Furthermore, the furanone showed a significantly lower activity on the activation of the expression of lipogenic genes compared to T0901317. Taken together, the furanone exhibited a weak cytotoxicity but had powerful TC- and TG-lowering effects most likely through targeting LXRα and PPARα, respectively. These findings indicate that the furanone has a potential application for the treatment of dyslipidaemia. Show less

Nobiletin (NOB), a functional ingredient found in citrus peel, is said to act against diabetes, obesity, and atherosclerosis. It has been reported to activate AMPK pathway, as well as increase SREBP1c, PPARα and PPARγ expression. However, no molecular mechanism has been elucidated to be able to integrate these sporadic findings with some controversies to lead to concrete outcomes. In this study, regulation of HDL biogenesis by NOB was investigated modulating ABCA1 and ABCG1 expression. Regulation of ABCA1/G1 by NOB was investigated in mouse macrophages J774.1. NOB increased mRNA and protein levels of ABCA1/G1, and cell cholesterol release by these factors. It also increased mRNA of PPARγ and LXRα but not PPARα. The increase in ABCA1/G1 mRNA levels by NOB was suppressed by antagonists of PPARγ and LXRα. The increase in PPARγ mRNA levels by NOB was suppressed by an LXRα antagonist, and the increase in LXRα mRNA levels was suppressed by a PPARγ antagonist. NOB increased CD36 mRNA and this was suppressed by an LXRα antagonist. The increase in ABCA1 mRNA by a PPARγ agonist was also suppressed by an LXRα antagonist. NOB did not influence LPL1 mRNA expression levels. NOB stimulated AMPK phosphorylation, and the increase in ABCA1/G1, LXRα and PPARγ mRNA levels and ABCA1/G1 protein levels by NOB was reversed by an AMPK inhibitor. AMPK siRNA suppressed ABCA1 expression. NOB activates AMPK and subsequently LXRα to promote the expression of ABCA1 and ABCG1, and an LXRα - PPARγ loop pathway amplifies these signals. Show less

We conducted a clinical trial with 22 healthy volunteers to investigate the effects of pregnane X receptor (PXR) agonist rifampin on blood pressure (BP). The study was randomized, crossover, single-blind, and placebo-controlled. Rifampin 600 mg or placebo once daily was administered for a week and the 24-hour ambulatory BP was monitored at the end of each arm on the eighth day. Rifampin elevated the mean systolic and diastolic 24-hour BP (4.7 mmHg, P < 0.0001, and 3.0 mmHg, P < 0.001, respectively) as well as the mean heart rate (3.5 bpm, P = 0.038). The serum renin concentration and the plasma renin activity were increased. Although rifampin increased circulating 4β-hydroxycholesterol (4βHC) as expected, the plasma 4βHC concentration strongly negatively correlated with 24-hour BP, especially systolic, in both rifampin and placebo arms (rifampin systolic BP, r = -0.69, P < 0.001; placebo systolic BP, r = -0.70, P < 0.001). The 4βHC, an agonist for liver X receptor (LXR), induced renin expression modestly in LXR-α expressing Calu-6 cells but only at unphysiologically high 4βHC concentrations. In conclusion, rifampin stimulates renin activity and has a hypertensive effect. This finding should be considered when designing interaction studies involving rifampin or other PXR agonists. Furthermore, PXR may represent a putative therapeutic target for the treatment of hypertension. Show less

Increased cholesterol efflux from macrophage foam cells in the subendothelial space confers protection against atherosclerosis. Soraphen A, a myxobacterial macrolactone, is an inhibitor of acetyl coenzyme A carboxylases (ACC), which control fatty acid synthesis and oxidation. To assess a potential direct link between macrophage cholesterol efflux and ACC inhibition, we examined [ Show less

Osteoarthritis (OA) is the most common joint disease that characterized by the degradation of articular cartilage. In this study, we aimed to investigate the anti-inflammatory activity of dioscin on IL-1β-stimulated human osteoarthritis chondrocytes. The production of PGE2 and NO was measured in this study. MMP1 and MMP3 were detected by ELISA. The expression of LXRα and NF-κB were tested by western blot analysis. Treatment of dioscin suppressed the production of PGE2 and NO, as well as the expression of COX-2 and iNOS (their key regulatory genes). Dioscin also attenuated the secretion of MMP1 and MMP3. Furthermore, dioscin inhibited the phosphorylation of NF-κB p65 and IκBα induced by IL-1β. The degradation of IκBα induced by IL-1β was also suppressed by dioscin. Dioscin increased the expression of LXRα and pretreatment of GGPP, the LXRα inhibitor, blocked the anti-inflammatory effects of dioscin. In conclusion, this study indicated that dioscin-mediated anti-inflammatory effect may be involved in the activation of LXRα. Show less

Psoriasis is an immune-mediated chronic inflammatory skin disease. Keratinocyte hyperproliferation has been regarded as a significant event in psoriasis pathogenesis. Considering the vital role of miRNA-mediated mRNA repression in psoriasis pathogenesis, in the present study, we attempted to investigate the mechanism of keratinocyte overproliferation from the point of miRNA-mRNA regulation. Both online microarray expression profiles and experimental results indicated that the expression of LXR-α and PPAR-γ was downregulated in psoriasis lesion skin. LXR-α or PPAR-γ overexpression alone was sufficient to inhibit keratinocyte proliferation, decrease KRT5 and KRT14 protein levels and increase KRT1 and KRT10 protein levels. miR-203 negatively regulated LXR-α and PPAR-γ expression through direct targeting. miR-203 inhibition exerted the opposite effects to LXR-α or PPAR-γ overexpression on HaCaT cells. More importantly, LXR-α or PPAR-γ overexpression could markedly remarkably attenuate the effects of miR-203 overexpression in keratinocytes, indicating that miR-203 promotes keratinocyte proliferation by targeting LXR-α and PPAR-γ. In conclusion, the miR-203-LXR-α/PPAR-γ axis modulates the proliferation of keratinocytes and might be a novel target for psoriasis treatment, which needs further in vivo investigation. Show less

Effective treatments and animal models for the most prevalent neurodegenerative form of blindness in elderly people, called age-related macular degeneration (AMD), are lacking. Genome-wide association studies have identified lipid metabolism and inflammation as AMD-associated pathogenic pathways. Given liver X receptors (LXRs), encoded by the nuclear receptor subfamily 1 group H members 2 and 3 (NR1H3 and NR1H2), are master regulators of these pathways, herein we investigated the role of LXR in human and mouse eyes as a function of age and disease and tested the therapeutic potential of targeting LXR. We identified immunopositive LXR fragments in human extracellular early dry AMD lesions and a decrease in LXR expression within the retinal pigment epithelium (RPE) as a function of age. Aged mice lacking LXR presented with isoform-dependent ocular pathologies. Specifically, loss of the Nr1h3 isoform resulted in pathobiologies aligned with AMD, supported by compromised visual function, accumulation of native and oxidized lipids in the outer retina, and upregulation of ocular inflammatory cytokines, while absence of Nr1h2 was associated with ocular lipoidal degeneration. LXR activation not only ameliorated lipid accumulation and oxidant-induced injury in RPE cells but also decreased ocular inflammatory markers and lipid deposition in a mouse model, thereby providing translational support for pursuing LXR-active pharmaceuticals as potential therapies for dry AMD. Show less

Bisphenol A (BPA) and its replacement analog, bisphenol S (BPS), have been proposed as environmental obesogen to disrupt the lipid metabolism through regulating peroxisome proliferator-activated receptor gamma (PPARγ) receptor. However, there is a dearth of information on whether this biological effect can occur in human macrophage, a cell type which closely interacts with adipocytes and hepatocytes to control lipid metabolism. Here, we for the first time investigate the activity of BPA and BPS on PPARγ pathway in human macrophages. The results demonstrated that BPA and BPS served as activators of PPARγ in human macrophage cell line, and significantly induced the expression of lipid metabolism-related genes, including fatty acid binding protein 4 (FABP4), cluster of differentiation 36 (CD36) and nuclear receptor subfamily 1 group H member 3 (NR Show less

Liver X receptor alpha (Lxrα) is a sterol-regulated transcription factor that limits atherogenesis by regulating cholesterol homeostasis and inflammation in macrophages. Transcriptional profiling identified the reverse cholesterol transport protein Arf-like 7 (Arl7, Arl4c) as a Lxrα target gene. We hypothesized that the LXR response element (LXRE) sequence on the murine macrophage Arl7 promoter may play a critical role in Lxrα's atherosuppressive effects. Employing low density lipoprotein receptor-deficient mice with macrophage-specific Lxrα overexpression (Ldlr Ldlr Lxrα's anti-atherosclerotic effects in Ldlr Show less

Sorafenib resistance is a major obstacle to the treatment of advanced hepatocellular carcinoma (HCC). MicroRNAs (miRNAs) are multifunctional regulators of gene expression with profound impact for human disease. Therefore, better understanding of the biological mechanisms of abnormally expressed miRNAs is critical to discovering novel, promising therapeutic targets for HCC treatment. This study aimed to investigate the role of miR-378a-3p in the sorafenib resistance of HCC and elucidate the underlying molecular mechanisms. Show less

Silicosis, a severe and irreversible form of pulmonary fibrosis (PF) caused by long-term exposure to dust particles in production environments, is the biggest occupational health concern in China and most low-income countries. The transdifferentiation of pulmonary fibroblasts is the terminal event in silicosis, and specific transcription factors (TFs) play a crucial role in this condition. However, the relationship between TF-mediated regulation and silicosis remains unknown. We performed a transcriptomic analysis to elucidate this relationship, and our results revealed that two TFs, EGR2 and BHLHE40, were upregulated and five, i.e., TBX2, NR1H3 (LXRα), NR2F1, PPARG (PPARγ), and EPAS1, were downregulated in activated fibroblasts. Notably, PPARγ and LXRα expression was also decreased in an experimental mouse model of silicosis. The mechanism underlying these changes may involve TGF-β1 secretion from silica-exposed alveolar macrophages, causing PPARγ and LXRα downregulation, which in turn would result in aberrant α-SMA transcription. Our results suggest that LXRα is a potential target for the prevention of silicosis and PF. Show less

The uptake of modified low-density lipoprotein (LDL) and the accumulation of lipid droplets induce the formation of vascular smooth muscle cells (VSMCs)-derived foam cells, thereby promoting the development and maturation of plaques and accelerating the progression of atherosclerosis. Celastrol is a quinine methide triterpenoid isolated from the root bark of traditional Chinese herb Tripterygium wilfordii. It possesses various biological properties, including anti-obesity, cardiovascular protection, anti-inflammation, etc. In the present study, we found that celastrol significantly reduced lipid accumulation induced by oxidized LDL (ox-LDL) in VSMCs. Mechanistically, celastrol up-regulated adenosine triphosphate-binding cassette transporter A1 (ABCA1) expression through activating liver X receptor α (LXRα) expression, which contributed to inhibit lipid accumulation in VSMCs. Meanwhile, celastrol decreased lipid accumulation by triggering autophagy in VSMCs. Therefore, these findings supported celastrol as a potentially effective agent for the prevention and therapy of atherosclerosis. Show less

Compared to other mammalian species, porcine oocytes and embryos are characterized by large amounts of lipids stored mainly in the form of droplets in the cytoplasm. The amount and the morphology of lipid droplets (LD) change throughout the preimplantation development, however, relatively little is known about expression of genes involved in lipid metabolism of early embryos. We compared porcine and bovine blastocyst stage embryos as well as dissected inner cell mass (ICM) and trophoblast (TE) cell populations with regard to lipid droplet storage and expression of genes functionally annotated to selected lipid gene ontology terms using RNA-seq. Comparing the number and the volume occupied by LD between bovine and porcine blastocysts, we have found significant differences both at the level of single embryo and a single blastomere. Aside from different lipid content, we found that embryos regulate the lipid metabolism differentially at the gene expression level. Out of 125 genes, we found 73 to be differentially expressed between entire porcine and bovine blastocyst, and 36 and 51 to be divergent between ICM and TE cell lines. We noticed significant involvement of cholesterol and ganglioside metabolism in preimplantation embryos, as well as a possible shift towards glucose, rather than pyruvate dependence in bovine embryos. A number of genes like Show less

In the present study, we investigated the effects of xanthine oxidase (XO) inhibition on cholesterol-induced renal dysfunction in chronic kidney disease (CKD) mice, and in low-density lipoprotein (LDL)-treated human kidney proximal tubule epithelial (HK-2) cells. ApoE knockout (KO) mice underwent uninephrectomy to induce CKD, and were fed a normal diet or high-cholesterol (HC) diet along with the XO inhibitor topiroxostat (1 mg/kg/day). HK-2 cells were treated with LDL (200 µg/mL) and topiroxostat (5 µM) or small interfering RNA against xanthine dehydrogenase (siXDH; 20 nM). In uninephrectomized ApoE KO mice, the HC diet increased cholesterol accumulation, oxidative stress, XO activity, and kidney damage, while topiroxostat attenuated the hypercholesterolemia-associated renal dysfunction. The HC diet induced cholesterol accumulation by regulating the expressions of genes involved in cholesterol efflux ( Show less

Atherosclerosis (AS) is the most common cardiovascular disease, and reverse cholesterol transport (RCT) plays an important role in maintaining cholesterol homeostasis. Both endoplasmic reticulum (ER) stress and LXRα can affect the metabolism of cholesterol. However, whether ER stress can modulate cholesterol metabolism by LXRα in hepatocytes and macrophages remains unclear. Therefore, in this study, we aimed to explore the relationship between ER stress induced by tunicamycin and LXRα in hepatocytes and macrophages and clarify their possible mechanisms and roles in AS. C57BL/6 mice and Huh-7 and THP-1 cells were treated with tunicamycin and LXR-623 (an agonist of LXRα) alone or in combination. Tunicamycin-induced ER stress caused liver injury; promoted the accumulation of cholesterol and triglycerides; inhibited the expression of LXRα, ABCA1 and ABCG1 in the livers of mice, thus reducing serum high-density lipoprotein (HDL)-C, low-density lipoprotein (LDL)-C, total cholesterol and triglyceride levels; however, LXR-623 could attenuate ER stress and reverse these changes. We also obtained the same results in Huh-7 and THP-1 cells. ER stress induced by tunicamycin could clearly be reversed by activating LXRα because it promoted cholesterol efflux by enhancing the expression of ABCA1 and ABCG1 in hepatocytes and macrophages, contributing to attenuation of the development of AS. Show less

Nonalcoholic fatty liver disease (NAFLD) is regarded as a threat to public health; however, the pathologic mechanism of NAFLD is not fully understood. We attempted to identify abnormally expressed long noncoding RNA (lncRNAs) and messenger RNA that may affect the occurrence and development of NAFLD in this study. The expression of differentially expressed lncRNAs in NAFLD was determined in oleic acid (OA)-treated L02 cells, and the functions of CCAT1 in lipid droplet formation were evaluated in vitro. Differentially expressed genes (DEGs) were analyzed by microarray analysis, and DEGs related to CCTA1 were selected and verified by weighted correlation network analysis. The dynamic effects of LXRα and CCTA1 on lipid droplet formation and predicted binding was examined. The binding between miR-631 and CCAT1 and LXRα was verified. The dynamic effects of miR-613 inhibition and CCTA1 silencing on lipid droplet formation were examined. The expression and correlations of miR-631, CCAT1, and LXRα were determined in tissue samples. As the results show, CCAT1 was induced by OA and upregulated in NAFLD clinical samples. CCAT1 silencing significantly suppressed lipid droplet accumulation in vitro. LXRα was positively correlated with CCAT1. By inhibiting miR-613, CCAT1 increased the transcription of LXRα and promoted LXRα expression. The expression of LXRα was significantly increased in NAFLD tissues and was positively correlated with CCAT1. In conclusion, CCAT1 increases LXRα transcription by serving as a competing endogenous RNA for miR-613 in an LXRE-dependent manner, thereby promoting lipid droplet formation and NAFLD. CCAT1 and LXRα might be potent targets for NAFLD treatment. Show less

Atherosclerosis (AS) is the killer of human health and longevity, which is majorly caused by oxidized lipoproteins that attack macrophages in the endarterium. The Shen-Hong-Tong-Luo (SHTL) formula has shown great clinical efficacy and vascular protective effect for over 30 years in China, to attenuate AS progression. However, its pharmacological mechanism needs more investigation. In this study, we first investigated the chemical composition of SHTL by fingerprint analysis using high-performance liquid chromatography. In primary mouse peritoneal macrophages induced by lipopolysaccharide (LPS), we found that SHTL pretreatment suppressed reactive oxygen species accumulation and reversed the increases of the inflammatory factors, TNF- Show less

Tumor microenvironments are strongly related to tumor development, and immune-infiltrating cells and immune-related molecules are potential prognostic markers. However, the shortcomings of traditional measurement methods limit the accurate evaluation of various components in tumor microenvironments. With the rapid advancement of Next-Generation RNA Sequencing technology, dedicated and in-depth analyses of immune filtration within the tumor microenvironment has been achieved. In this study, we combined the bioinformatics analysis methods ESTIMATE, CIBERSORT, and ssGSEA to characterize the immune infiltration of sarcomas and to identify specific immunomodulators of different pathological subtypes. We further extracted a functional enrichment of significant immune-related genes related to improved prognosis, including NR1H3, VAMP5, GIMAP2, GBP2, HLA-E and CRIP1. Overall, the immune microenvironment is an important prognostic determinant of sarcomas and may be a potential resource for developing effective immunotherapy. Show less

Sorghum bicolor (SB) is rich in protective phytoconstituents with health benefits and regarded as a promising source of natural anti-diabetic substance. However, its comprehensive bioactive compound(s) and mechanism(s) against type-2 diabetes mellitus (T2DM) have not been exposed. Hence, we implemented network pharmacology to identify its key compounds and mechanism(s) against T2DM. Compounds in SB were explored through GC-MS and screened by Lipinski's rule. Genes associated with the selected compounds or T2DM were extracted from public databases, and the overlapping genes between SB-compound related genes and T2DM target genes were identified using Venn diagram. Then, the networking between selected compounds and overlapping genes was constructed, visualized, and analyzed by RStudio. Finally, affinity between compounds and genes was evaluated via molecular docking. GC-MS analysis of SB detected a total of 20 compounds which were accepted by the Lipinski's rule. A total number of 16 compounds-related genes and T2DM-related genes (4,763) were identified, and 81 overlapping genes between them were selected. Gene set enrichment analysis exhibited that the mechanisms of SB against T2DM were associated with 12 signaling pathways, and the key mechanism might be to control blood glucose level by activating PPAR signaling pathway. Furthermore, the highest affinities were noted between four main compounds and six genes (FABP3-Propyleneglyco monoleate, FABP4-25-Oxo-27-norcholesterol, NR1H3-Campesterol, PPARA-β-sitosterol, PPARD-β-sitosterol, and PPARG-β-sitosterol). Our study overall suggests that the four key compounds detected in SB might ameliorate T2DM severity by activating the PPAR signaling pathway. Show less

Apolipoprotein A-I mimetic peptides are amphipathic alpha-helix peptides that display similar functions to apolipoprotein A-I. Preclinical and clinical studies have demonstrated the safety and efficacy of apolipoprotein A-I mimetic peptides in multiple indications associated with inflammatory processes. In this study, we evaluated the effect of the long-term expression of L37pA in the liver by an adeno-associated virus (AAV-L37pA) on the expression of an adeno-associated virus encoding interferon-alpha (AAV-IFNα). Long-term IFNα expression in the liver leads to lethal hematological toxicity one month after AAV administration. Concomitant administration of AAV-L37pA prevented the lethal toxicity since the IFNα expression was reduced one month after AAV administration. To identify the mechanism of action of L37pA, a genomic and proteomic analysis was performed 15 days after AAV administration when a similar level of IFNα and interferon-stimulated genes were observed in mice treated with AAV-IFNα alone and in mice treated with AAV-IFNα and AAV-L37pA. The coexpression of the apolipoprotein A-I mimetic peptide L37pA with IFNα modulated the gene expression program of IFNα, inducing a significant reduction in inflammatory pathways affecting pathogen-associated molecular patterns receptor, dendritic cells, NK cells and Th1 immune response. The proteomic analysis confirmed the impact of the L37pA activity on several inflammatory pathways and indicated an activation of LXR/RXR and PPPARα/γ nuclear receptors. Thus, long-term expression of L37pA induces an anti-inflammatory effect in the liver that allows silencing of IFNα expression mediated by an adeno-associated virus. Show less

Biochanin A (BCA), a dietary isoflavone extracted from red clover and cabbage, has been shown to antagonize hypertension and myocardial ischemia/reperfusion injury. However, very little is known about its role in atherogenesis. The aim of this study was to observe the effects of BCA on atherosclerosis and explore the underlying mechanisms. Our results showed that administration of BCA promoted reverse cholesterol transport (RCT), improved plasma lipid profile, and decreased serum proinflammatory cytokine levels and atherosclerotic lesion area in apoE Show less

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 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 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. Show less