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Bai X, Wang S, Shu L, Cao Q, Hu H, Zhu Y, Chen C. Hawthorn leaf flavonoids alleviate the deterioration of atherosclerosis by inhibiting SCAP-SREBP2-LDLR pathway through sPLA2-ⅡA signaling in macrophages in mice. JOURNAL OF ETHNOPHARMACOLOGY 2024; 327:118006. [PMID: 38442806 DOI: 10.1016/j.jep.2024.118006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/23/2024] [Accepted: 03/01/2024] [Indexed: 03/07/2024]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Hawthorn leaves are a combination of the dried leaves of the Rosaceae plants, i.e., Crataegus pinnatifida Bge. or Crataegus pinnatifida Bge. var. major N. E. Br., is primarily cultivated in East Asia, North America, and Europe. hawthorn leaf flavonoids (HLF) are the main part of extraction. The HLF have demonstrated potential in preventing hypertension, inflammation, hyperlipidemia, and atherosclerosis. However, the potential pharmacological mechanism behind its anti-atherosclerotic effect has yet to be explored. AIM OF THE STUDY The in vivo and in vitro effects of HLF on lipid-mediated foam cell formation were investigated, with a specific focus on the levels of secreted phospholipase A2 type IIA (sPLA2-II A) in macrophage cells. MATERIALS AND METHODS The primary constituents of HLF were analyzed using ultra-high performance liquid chromatography and liquid chromatography-tandem mass spectrometry. In vivo, HLF, at concentrations of 5 mg/kg, 20 mg/kg, and 40 mg/kg, were administered to apolipoprotein E knockout mice (ApoE-/-) fed by high-fat diet (HFD) for 16 weeks. Aorta and serum samples were collected to identify lesion areas and lipids through mass spectrometry analysis to dissect the pathological process. RAW264.7 cells were incubated with oxidized low-density lipoprotein (ox-LDL) alone, or ox-LDL combined with different doses of HLF (100, 50, and 25 μg/ml), or ox-LDL plus 24-h sPLA2-IIA inhibitors, for cell biology analysis. Lipids and inflammatory cytokines were detected using biochemical analyzers and ELISA, while plaque size and collagen content of plaque were assessed by HE and the Masson staining of the aorta. The lipid deposition in macrophages was observed by Oil Red O staining. The expression of sPLA2-IIA and SCAP-SREBP2-LDLR was determined by RT-qPCR and Western blot analysis. RESULTS The chemical profile of HLF was studied using UPLC-Q-TOF-MS/MS, allowing the tentative identification of 20 compounds, comprising 1 phenolic acid, 9 flavonols and 10 flavones, including isovitexin, vitexin-4″-O-glucoside, quercetin-3-O-robibioside, rutin, vitexin-2″-O-rhamnoside, quercetin, etc. HLF decreased total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and non-high-density lipoprotein cholesterol (non-HDL-C) levels in ApoE-/- mice (P < 0.05), reduced ox-LDL uptake, inhibited level of inflammatory factors, such as IL-6, IL-8, TNF-α, and IL-1ꞵ (P < 0.001), and alleviated aortic plaques with a thicker fibrous cap. HLF effectively attenuated foam cell formation in ox-LDL-treated RAW264.7 macrophages, and reduced levels of intracellular TC, free cholesterol (FC), cholesteryl ester (CE), IL-6, TNF-α, and IL-1β (P < 0.001). In both in vivo and in vitro experiments, HLF significantly downregulated the expression of sPLA2-IIA, SCAP, SREBP2, LDLR, HMGCR, and LOX-1 (P < 0.05). Furthermore, sPLA2-IIA inhibitor effectively mitigated inflammatory release in RAW264.7 macrophages and regulated SCAP-SREBP2-LDLR signaling pathway by inhibiting sPLA2-IIA secretion (P < 0.05). CONCLUSION HLF exerted a protective effect against atherosclerosis through inhibiting sPLA2-IIA to diminish SCAP-SREBP2-LDLR signaling pathway, to reduce LDL uptake caused foam cell formation, and to slow down the progression of atherosclerosis in mice.
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Affiliation(s)
- Xufeng Bai
- College of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, 330004, China
| | - Shuwen Wang
- College of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, 330004, China
| | - Limei Shu
- College of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, 330004, China
| | - Qingyu Cao
- College of Pharmacy, Nanchang Medical College, Nanchang, Jiangxi, 330052, China
| | - Huiming Hu
- College of Pharmacy, Nanchang Medical College, Nanchang, Jiangxi, 330052, China; Key Laboratory of Pharmacodynamics and Quality Evaluation on Anti-Inflammatory Chinese Herbs, Jiangxi Administration of Traditional Chinese Medicine, Jiangxi, 330052, China; School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, Queensland, 4072, Australia.
| | - Yanchen Zhu
- College of Computer Science, Jiangxi University of Chinese Medicine, Nanchang, Jiangxi, 330004, China.
| | - Chen Chen
- School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, Queensland, 4072, Australia.
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Abstract
All mammalian cell membranes contain cholesterol to maintain membrane integrity. The transport of this hydrophobic lipid is mediated by lipoproteins. Cholesterol is especially enriched in the brain, particularly in synaptic and myelin membranes. Aging involves changes in sterol metabolism in peripheral organs and also in the brain. Some of those alterations have the potential to promote or to counteract the development of neurodegenerative diseases during aging. Here, we summarize the current knowledge of general principles of sterol metabolism in humans and mice, the most widely used model organism in biomedical research. We discuss changes in sterol metabolism that occur in the aged brain and highlight recent developments in cell type-specific cholesterol metabolism in the fast-growing research field of aging and age-related diseases, focusing on Alzheimer's disease. We propose that cell type-specific cholesterol handling and the interplay between cell types critically influence age-related disease processes.
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Affiliation(s)
- Gesine Saher
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany;
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Sunwoo JY, Eliasberg CD, Carballo CB, Rodeo SA. The role of the macrophage in tendinopathy and tendon healing. J Orthop Res 2020; 38:1666-1675. [PMID: 32190920 DOI: 10.1002/jor.24667] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 03/12/2020] [Indexed: 02/04/2023]
Abstract
The role of the macrophage is an area of emerging interest in tendinopathy and tendon healing. The macrophage has been found to play a key role in regulating the healing process of the healing tendon. The specific function of the macrophage depends on its functional phenotype. While the M1 macrophage phenotype exhibits a phagocytic and proinflammatory function, the M2 macrophage phenotype is associated with the resolution of inflammation and tissue deposition. Several studies have been conducted on animal models looking at enhancing or suppressing macrophage function, targeting specific phenotypes. These studies include the use of exogenous biological and pharmacological substances and more recently the use of transgenic and genetically modified animals. The outcomes of these studies have been promising. In particular, enhancement of M2 macrophage activity in the healing tendon of animal models have shown decreased scar formation, accelerated healing, decreased inflammation and even enhanced biomechanical strength. Currently our understanding of the role of the macrophage in tendinopathy and tendon healing is limited. Furthermore, the roles of therapies targeting macrophages to enhance tendon healing is unclear. Clinical Significance: An increased understanding of the significance of the macrophage and its functional phenotypes in the healing tendon may be the key to enhancing tendon healing. This review will present the current literature on the function of macrophages in tendinopathy and tendon healing and the potential of therapies targeting macrophages to enhance tendon healing.
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Affiliation(s)
- Joo Y Sunwoo
- Orthopaedic Soft Tissue Research Program, Hospital for Special Surgery, New York, New York
| | - Claire D Eliasberg
- Orthopaedic Soft Tissue Research Program, Hospital for Special Surgery, New York, New York
| | - Camila B Carballo
- Orthopaedic Soft Tissue Research Program, Hospital for Special Surgery, New York, New York
| | - Scott A Rodeo
- Orthopaedic Soft Tissue Research Program, Hospital for Special Surgery, New York, New York
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4
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Zhong Y, Liu C, Feng J, Li JF, Fan ZC. Curcumin affects ox-LDL-induced IL-6, TNF-α, MCP-1 secretion and cholesterol efflux in THP-1 cells by suppressing the TLR4/NF-κB/miR33a signaling pathway. Exp Ther Med 2020; 20:1856-1870. [PMID: 32782494 PMCID: PMC7401289 DOI: 10.3892/etm.2020.8915] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 02/26/2020] [Indexed: 12/21/2022] Open
Abstract
The aim of the present study was to study the molecular mechanism of how curcumin decreases the formation of ox-LDL induced human monocyte macrophage foam cells, promotes the efflux of cholesterol and reduces the secretion of inflammatory cytokines. In vitro cultured THP-1 cells were induced to become macrophages using phorbol-12-myristate-13-acetate. The cells were then pre-treated with curcumin before inducing the foam cell model by addition of oxidized low-density lipoprotein (ox-LDL). Western blot assays were used to detect expression levels of toll-like receptor (TLR)4, nuclear factor κB (NF-κB), NF-κB inhibitor α (IκBα), phosphorylated-IκBα and ATP binding cassette transporter (ABC)A1. Reverse transcription-quantitative PCR was employed to examine mRNA levels of TLR4, microRNA (miR)33a and ABCA1. ELISAs were used to detect inflammatory factors, including tumor necrosis factor (TNF)-α, monocyte chemotactic protein (MCP)-1 and interleukin (IL)-6. ox-LDL successfully induced the foam cell model, promoted phosphorylation of IκBα, promoted nuclear translocation of NF-κB, promoted the expression of TLR4 and miR33a, and promoted the secretion of TNF-α, MCP-1 and Il-6. Additionally, ox-LDL reduced the expression of ABCA1 and cholesterol efflux. However, pretreatment with curcumin increased the expression of ABCA1 and cholesterol efflux and suppressed secretion of TNF-α, MCP-1 and Il-6. TLR4 antibodies, the NF-κB blocker, PDTC, and the miR33a inhibitor also reduced the abnormal transformations induced by ox-LDL. Curcumin promoted cholesterol efflux by suppressing the TLR4/NF-κB/miR33a signaling pathway, and reduced the formation of foam cells and the secretion of inflammatory factors.
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Affiliation(s)
- Yi Zhong
- Department of Cardiology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, P.R. China
| | - Cheng Liu
- Department of Cardiovascular Ultrasound and Cardiac Function, Sichuan Provincial People's Hospital, Chengdu, Sichuan 610000, P.R. China.,Ultrasound in Cardiac Electrophysiology and Biomechanics Key Laboratory of Sichuan Province, Chengdu, Sichuan 610000, P.R. China
| | - Jian Feng
- Department of Cardiology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, P.R. China
| | - Jia-Fu Li
- Department of Cardiology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, P.R. China
| | - Zhong-Cai Fan
- Department of Cardiology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, P.R. China
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The cellular function of SCAP in metabolic signaling. Exp Mol Med 2020; 52:724-729. [PMID: 32385422 PMCID: PMC7272406 DOI: 10.1038/s12276-020-0430-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 03/26/2020] [Accepted: 03/31/2020] [Indexed: 12/16/2022] Open
Abstract
Sterol regulatory element binding protein (SREBP) cleavage activating protein (SCAP) is a key regulator of SREBP maturation. SCAP induces translocation of SREBP from the endoplasmic reticulum to the Golgi apparatus, allowing it to regulate cellular triglyceride and cholesterol levels. Previous studies have shown that suppression of SREBP activation in SCAP conditional knockout mice reduced the accumulation of intracellular triglycerides, which eventually causes the development of metabolic diseases such as atherosclerosis, diabetes, hepatic steatosis, and insulin resistance. However, despite the significance of SCAP as a regulator of SREBP, its function has not been thoroughly discussed. In this review, we have summarized the function of SCAP and its regulatory proteins. Furthermore, we discuss recent studies regarding SCAP as a possible therapeutic target for hypertriglyceridemia and hyperlipidemia.
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Opazo-Ríos L, Mas S, Marín-Royo G, Mezzano S, Gómez-Guerrero C, Moreno JA, Egido J. Lipotoxicity and Diabetic Nephropathy: Novel Mechanistic Insights and Therapeutic Opportunities. Int J Mol Sci 2020; 21:E2632. [PMID: 32290082 PMCID: PMC7177360 DOI: 10.3390/ijms21072632] [Citation(s) in RCA: 170] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/07/2020] [Accepted: 04/08/2020] [Indexed: 02/06/2023] Open
Abstract
Lipotoxicity is characterized by the ectopic accumulation of lipids in organs different from adipose tissue. Lipotoxicity is mainly associated with dysfunctional signaling and insulin resistance response in non-adipose tissue such as myocardium, pancreas, skeletal muscle, liver, and kidney. Serum lipid abnormalities and renal ectopic lipid accumulation have been associated with the development of kidney diseases, in particular diabetic nephropathy. Chronic hyperinsulinemia, often seen in type 2 diabetes, plays a crucial role in blood and liver lipid metabolism abnormalities, thus resulting in increased non-esterified fatty acids (NEFA). Excessive lipid accumulation alters cellular homeostasis and activates lipogenic and glycogenic cell-signaling pathways. Recent evidences indicate that both quantity and quality of lipids are involved in renal damage associated to lipotoxicity by activating inflammation, oxidative stress, mitochondrial dysfunction, and cell-death. The pathological effects of lipotoxicity have been observed in renal cells, thus promoting podocyte injury, tubular damage, mesangial proliferation, endothelial activation, and formation of macrophage-derived foam cells. Therefore, this review examines the recent preclinical and clinical research about the potentially harmful effects of lipids in the kidney, metabolic markers associated with these mechanisms, major signaling pathways affected, the causes of excessive lipid accumulation, and the types of lipids involved, as well as offers a comprehensive update of therapeutic strategies targeting lipotoxicity.
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Affiliation(s)
- Lucas Opazo-Ríos
- Renal, Vascular and Diabetes Research Laboratory, IIS-Fundación Jiménez Díaz, Universidad Autónoma de Madrid, Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), 28040 Madrid, Spain; (L.O.-R.); (G.M.-R.); (C.G.-G.); (J.E.)
| | - Sebastián Mas
- Renal, Vascular and Diabetes Research Laboratory, IIS-Fundación Jiménez Díaz, Universidad Autónoma de Madrid, Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), 28040 Madrid, Spain; (L.O.-R.); (G.M.-R.); (C.G.-G.); (J.E.)
| | - Gema Marín-Royo
- Renal, Vascular and Diabetes Research Laboratory, IIS-Fundación Jiménez Díaz, Universidad Autónoma de Madrid, Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), 28040 Madrid, Spain; (L.O.-R.); (G.M.-R.); (C.G.-G.); (J.E.)
| | - Sergio Mezzano
- Laboratorio de Nefrología, Facultad de Medicina, Universidad Austral de Chile, 5090000 Valdivia, Chile;
| | - Carmen Gómez-Guerrero
- Renal, Vascular and Diabetes Research Laboratory, IIS-Fundación Jiménez Díaz, Universidad Autónoma de Madrid, Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), 28040 Madrid, Spain; (L.O.-R.); (G.M.-R.); (C.G.-G.); (J.E.)
| | - Juan Antonio Moreno
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, 14004 Cordoba, Spain
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), University of Cordoba, 14004 Cordoba, Spain
- Hospital Universitario Reina Sofía, 14004 Cordoba, Spain
| | - Jesús Egido
- Renal, Vascular and Diabetes Research Laboratory, IIS-Fundación Jiménez Díaz, Universidad Autónoma de Madrid, Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), 28040 Madrid, Spain; (L.O.-R.); (G.M.-R.); (C.G.-G.); (J.E.)
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7
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Ouyang N, Gan H, He Q, Lei H, Wang SY, Liu Q, Zhou C. Dysfunction of cholesterol sensor SCAP promotes inflammation activation in THP-1 macrophages. Exp Cell Res 2018; 367:162-169. [PMID: 29596892 DOI: 10.1016/j.yexcr.2018.03.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 03/15/2018] [Accepted: 03/24/2018] [Indexed: 01/19/2023]
Abstract
Crosstalk occurs between dyslipidemia and chronic inflammation, which are both precipitants of atherosclerosis. Sterol regulatory element binding proteins cleavage-activating protein (SCAP) plays a key role in regulating cholesterol homeostasis. The present study investigated the effects of SCAP dysfunction on the expression of inflammatory cytokines and lipid metabolism in THP-1 macrophages. Intracellular cholesterol content was assessed by Oil Red O staining and quantitative assays. The expression of SCAP, HMGCR, pro-IL-1β and N-SREBP2, p65(N) in the nucleus were examined by real-time quantitative RT-PCR and Western blotting. The level of secretary proteins IL-1β, TNF-α and MCP-1 in the supernatants were determined by ELISA. The translocation of SCAP from the endoplasmic reticulum (ER) to the Golgi was detected by confocal microscopy. Our results demonstrated that over-expression of SCAP significantly increased the expression of HMGCR, pro-IL-1β in the cytoplasm, and mature IL-1β, TNF-α, MCP-1 in the supernatants, while knocking down SCAP dramatically decreased the expression of these molecules. Betulin effectively suppressed the accumulation of intracellular cholesterol in the SCAP over-expressed THP-1 macrophages, but did not affect the expression of inflammatory cytokines, indicating that the pro-inflammatory effect of SCAP was independent of its routine role in regulating cholesterol homeostasis. Furthermore, we investigated the molecular mechanisms mediating the crosstalk between dyslipidemia and inflammatory responses. Knocking down SCAP attenuated LPS-induced IκB phosphorylation and reduced the nuclear level of p65, while over-expression of SCAP increased the nuclear level of p65. Knocking down p65 abolished the proinflammatory effect represented by elevated expression of the inflammatory mediators in the SCAP over-expressed THP-1 macrophages, suggesting that SCAP dysfunction stimulated inflammatory responses via activating the NF-κB signaling pathway. In conclusion, the cholesterol sensor SCAP plays a role in regulating the expression of inflammatory factors such as IL-1β, TNF-α, and MCP-1 in THP-1 macrophages. SCAP mediates the inflammatory response via activating the NF-κB pathway. This new function of SCAP is independent of its role in lipid metabolism.
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Affiliation(s)
- Nan Ouyang
- Department of Nephrology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, PR China
| | - Hua Gan
- Department of Nephrology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, PR China
| | - Quan He
- Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, PR China
| | - Han Lei
- Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, PR China; Centre for Lipid Research, Key Laboratory of Metabolism on Lipid and Glucose, Chongqing Medical University, Chongqing 400016, PR China
| | - Stephen Y Wang
- Geisel School of Medicine at Dartmouth, 1 Rope Ferry Rd, Hanover, NH 03755, USA
| | - Qing Liu
- Centre for Clinical Research, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, PR China
| | - Chao Zhou
- Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, PR China; Centre for Lipid Research, Key Laboratory of Metabolism on Lipid and Glucose, Chongqing Medical University, Chongqing 400016, PR China.
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GP73 regulates Hepatic Steatosis by enhancing SCAP-SREBPs interaction. Sci Rep 2017; 7:14932. [PMID: 29097707 PMCID: PMC5668365 DOI: 10.1038/s41598-017-06500-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 05/25/2017] [Indexed: 11/09/2022] Open
Abstract
Elevated Golgi phosphoprotein 2 (GP73, also known as GOLPH2 or GOLM1) expression in serum and liver, which can be induced by viral infection and cytokine treatments, is intimately connected with liver disease, including acute hepatitis, cirrhosis and hepatocellular carcinoma (HCC). However, its pathogenic roles in hepatic diseases have never been clarified in detail. Here, we showed that the upregulated GP73 is indispensable for SREBPs activation and lipogenesis. Notably, GP73 overexpression enhanced SCAP-SREBPs binding and its Golgi trafficking even under cholesterol sufficiency. Consistent with these functional findings, GP73 blockage could alleviate tunicamycin-induced liver steatosis by reducing SREBPs activation. A significant positive correlation of GP73 with genes in lipid metabolism pathway was also identified in liver cancer based on data from The Cancer Genome Atlas (TCGA) dataset. Our findings revealed previously unrecognized role of GP73 in lipid metabolism.
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Digenic mutations on SCAP and AGXT2 predispose to premature myocardial infarction. Oncotarget 2017; 8:100141-100149. [PMID: 29245966 PMCID: PMC5725008 DOI: 10.18632/oncotarget.22045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 07/18/2017] [Indexed: 01/03/2023] Open
Abstract
Genetic factors play a vital role in the pathogenesis of premature myocardial infarction (PMI). However, current studies explained only small amounts of genetic risk in MI. In this study, we started from a PMI pedigree with three MI patients occurred at the age of 43, 45 and 53 respectively. Sanger sequencing revealed 6 LDLR mutation carriers in the family, but only one was diagnosed with PMI, indicating that the LDLR mutation may not be the reason for PMI. Upon exome-sequencing and bioinformatics analysis, two variants in SCAP and AGXT2 were identified as potential causative mutation for PMI. Further observation revealed that only patients that meet the diagnosis of PMI harbored two variants meantime, while other MI patients or members with no MI carried no more than one of the variants. Screening of the two genes in an independent PMI population identified another variant on SCAP (c.1403 T>C, p.Val468Ala), which was absent in 28, 000 east-Asian population. Further, the two variants on SCAP and AGXT2 were introduced into H293T and EA. hy926 cell lines respectively utilizing CRISPR-Cas9. Functional study revealed that the SCAP mutation impaired SCAP-SREBP feedback mechanism which may lead to a “constitutive activation” effect of cholesterol synthesis related genes, while the AGXT2 mutation reduced its aminotransferase activity leading to a down-regulation of NO production by ADMA accumulation. This study indicates that SCAP and AGXT2 are potential causative genes for PMI. Digenic mutation carriers may manifest a more severe phenotype, namely premature MI.
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Regulation of SREBP-2 intracellular trafficking improves impaired autophagic flux and alleviates endoplasmic reticulum stress in NAFLD. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:337-350. [PMID: 28011404 DOI: 10.1016/j.bbalip.2016.12.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 12/14/2016] [Accepted: 12/18/2016] [Indexed: 02/07/2023]
Abstract
Sterol regulatory element-binding protein 2 (SREBP-2), is a well-known transcriptional regulator of cholesterol metabolism. SREBP-2 is activated unconventionally to promote excessive cholesterol accumulation in non-alcoholic fatty liver disease (NAFLD). In addition, recent studies suggested that excessive lipid and cholesterol accumulation can weaken cellular autophagy function and promote endoplasmic reticulum stress (ERS). However, it remains unknown whether regulation of SREBP-2 processing modulates autophagy and ERS. In this study, we demonstrated that inhibition of SREBP-2 intracellular trafficking by site-1 protease (S1P) and site-2 protease (S2P) specific inhibitors, or shRNAs targeting S1P and S2P, upregulated gene and protein expression of autophagy markers, and improved the impaired autophagic flux induced in both cell and mouse models of NAFLD. Furthermore, increased lipid degradation by autophagy could repress PERK-P-EIF2α signaling. Taken together, these findings suggest that regulating the nuclear transport of SREBP-2 reduces lipid deposition and ERS via an autophagy-dependent pathway.
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Archer AM, Saber R, Rose S, Shaffer A, Misharin AV, Tsai F, Haines Iii GK, Dominguez S, Eren M, Vaughan DE, Cuda CM, Perlman H. ApoE deficiency exacerbates the development and sustainment of a semi-chronic K/BxN serum transfer-induced arthritis model. J Transl Med 2016; 14:170. [PMID: 27287704 PMCID: PMC4901400 DOI: 10.1186/s12967-016-0912-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 05/16/2016] [Indexed: 02/01/2023] Open
Abstract
Background The risk for developing cardiovascular disease is greater in patients with rheumatoid arthritis (RA) than in the general population. While patients with RA also have dyslipidemia, the impact of dyslipidemia on the severity of inflammatory arthritis and associated cardiovascular disease is unclear. Currently, there are conflicting results regarding arthritis incidence in apolipoprotein E (ApoE) deficient mice, which spontaneously exhibit both hyperlipidemia and atherosclerosis. Here, we utilize a distinct approach to investigate the contribution of a hyperlipidemic environment on the development of arthritis and atherosclerosis in mice lacking ApoE. Methods K/BxN serum transfer-induced arthritis (STIA) was assessed in C57BL/6 (control) and ApoE−/− mice using clinical indices and immunohistochemical staining. Ankle synoviums were processed for flow cytometry. Aortic atherosclerosis was quantitated using Sudan IV staining. Serum cholesterol and cytokine levels were determined via enzymatic and luminex bead-based assays, respectively. Results ApoE−/− mice developed a sustained and enhanced semi-chronic inflammatory arthritis as compared to control mice. ApoE−/− mice had increased numbers of foamy macrophages, enhanced joint inflammation and amplified collagen deposition versus controls. The presence of arthritis did not exacerbate serum cholesterol levels or significantly augment the level of atherosclerosis in ApoE−/− mice. However, arthritic ApoE−/− mice exhibited a marked elevation of IL-6 as compared to non-arthritic ApoE−/− mice and arthritic C57BL/6 mice. Conclusions Loss of ApoE potentiates a semi-chronic inflammatory arthritis. This heightened inflammatory response was associated with an increase in circulating IL-6 and in the number of foamy macrophages within the joint. Moreover, the foamy macrophages within the arthritic joint are reminiscent of those within unstable atherosclerotic lesions and suggest a pathologic role for foamy macrophages in propagating arthritis. Electronic supplementary material The online version of this article (doi:10.1186/s12967-016-0912-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Amy M Archer
- Division of Rheumatology, Department of Medicine, Northwestern University Feinberg School of Medicine, 240 East Huron Street, McGaw M338, Chicago, IL, 60611, USA
| | - Rana Saber
- Division of Rheumatology, Department of Medicine, Northwestern University Feinberg School of Medicine, 240 East Huron Street, McGaw M338, Chicago, IL, 60611, USA
| | - Shawn Rose
- Division of Rheumatology, Department of Medicine, Northwestern University Feinberg School of Medicine, 240 East Huron Street, McGaw M338, Chicago, IL, 60611, USA.,Immunoscience Exploratory Clinical and Translational Research, Bristol-Myers Squibb, Lawrenceville, NJ, USA
| | - Alexander Shaffer
- Division of Rheumatology, Department of Medicine, Northwestern University Feinberg School of Medicine, 240 East Huron Street, McGaw M338, Chicago, IL, 60611, USA
| | - Alexander V Misharin
- Division of Rheumatology, Department of Medicine, Northwestern University Feinberg School of Medicine, 240 East Huron Street, McGaw M338, Chicago, IL, 60611, USA.,Division of Pulmonary and Critical Care, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - FuNien Tsai
- Division of Rheumatology, Department of Medicine, Northwestern University Feinberg School of Medicine, 240 East Huron Street, McGaw M338, Chicago, IL, 60611, USA
| | | | - Salina Dominguez
- Division of Rheumatology, Department of Medicine, Northwestern University Feinberg School of Medicine, 240 East Huron Street, McGaw M338, Chicago, IL, 60611, USA
| | - Mesut Eren
- Division of Cardiology, Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Douglas E Vaughan
- Division of Cardiology, Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Carla M Cuda
- Division of Rheumatology, Department of Medicine, Northwestern University Feinberg School of Medicine, 240 East Huron Street, McGaw M338, Chicago, IL, 60611, USA.
| | - Harris Perlman
- Division of Rheumatology, Department of Medicine, Northwestern University Feinberg School of Medicine, 240 East Huron Street, McGaw M338, Chicago, IL, 60611, USA.
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Yang H, Yan L, Qian P, Duan H, Wu J, Li B, Wang S. Icariin inhibits foam cell formation by down-regulating the expression of CD36 and up-regulating the expression of SR-BI. J Cell Biochem 2016; 116:580-8. [PMID: 25389062 DOI: 10.1002/jcb.25009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 11/06/2014] [Indexed: 12/21/2022]
Abstract
Icariin is an important pharmacologically active flavonol diglycoside that can inhibit inflammation in lipopolysaccharide (LPS)-stimulated macrophages. However, little is known about the molecular mechanisms underlying the inhibitory effect of Icariin in the formation of foam cells. In this study, macrophages were cultured with LPS and oxidized low-density lipoprotein (oxLDL) in the presence or absence of Icariin. RT-PCR and western blot were used to detect the levels of mRNA and protein expression of CD36, scavenger receptor class B type I (SR-BI) and the phosphorylation of p38MAPK. It was demonstrated that 4 µM or 20 µM Icariin treatment significantly inhibited the cholesterol ester (CE)/total cholesterol (TC) and oxLDL-mediated foam cell formation (P < 0.05). The binding of oxLDL to LPS-activated macrophages was also significantly hindered by Icariin (P < 0.05). Furthermore, Icariin down-regulated the expression of CD36 in LPS-activated macrophages in a dose-dependent manner and CD36 over-expression restored the inhibitory effect of Icariin on foam cell formation. The phosphorylation of p38MAPK was reduced by Icariin, indicating that Icariin reduced the expression of CD36 through the p38MAPK pathway. In addition, Icariin up-regulated SR-BI protein expression in a dose-dependent manner, and SR-BI gene silencing restored the inhibitory effect of Icariin on foam cell formation. These data demonstrate that Icariin inhibited foam cell formation by down-regulating the expression of CD36 and up-regulating the expression of SR-BI. Therefore, our findings provide a new explanation as to why Icariin could inhibit atherosclerosis.
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Affiliation(s)
- Haitao Yang
- Department of Cardiology, Henan Provincial People's Hospital, Zhengzhou, 450003, China
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Mastrocola R, Nigro D, Chiazza F, Medana C, Dal Bello F, Boccuzzi G, Collino M, Aragno M. Fructose-derived advanced glycation end-products drive lipogenesis and skeletal muscle reprogramming via SREBP-1c dysregulation in mice. Free Radic Biol Med 2016; 91:224-35. [PMID: 26721591 DOI: 10.1016/j.freeradbiomed.2015.12.022] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 12/07/2015] [Accepted: 12/19/2015] [Indexed: 12/21/2022]
Abstract
Advanced Glycation End-Products (AGEs) have been recently related to the onset of metabolic diseases and related complications. Moreover, recent findings indicate that AGEs can endogenously be formed by high dietary sugars, in particular by fructose which is widely used as added sweetener in foods and drinks. The aim of the present study was to investigate the impact of a high-fructose diet and the causal role of fructose-derived AGEs in mice skeletal muscle morphology and metabolism. C57Bl/6J mice were fed a standard diet (SD) or a 60% fructose diet (HFRT) for 12 weeks. Two subgroups of SD and HFRT mice received the anti-glycative compound pyridoxamine (150 mg/kg/day) in the drinking water. At the end of protocol high levels of AGEs were detected in both plasma and gastrocnemius muscle of HFRT mice associated to impaired expression of AGE-detoxifying AGE-receptor 1. In gastrocnemius, AGEs upregulated the lipogenesis by multiple interference on SREBP-1c through downregulation of the SREBP-inhibiting enzyme SIRT-1 and increased glycation of the SREBP-activating protein SCAP. The AGEs-induced SREBP-1c activation affected the expression of myogenic regulatory factors leading to alterations in fiber type composition, associated with reduced mitochondrial efficiency and muscular strength. Interestingly, pyridoxamine inhibited AGEs generation, thus counteracting all the fructose-induced alterations. The unsuspected involvement of diet-derived AGEs in muscle metabolic derangements and proteins reprogramming opens new perspectives in pathogenic mechanisms of metabolic diseases.
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Affiliation(s)
- R Mastrocola
- Department of Clinical and Biological Sciences, University of Turin, Italy.
| | - D Nigro
- Department of Clinical and Biological Sciences, University of Turin, Italy
| | - F Chiazza
- Department of Drug Science and Technology, University of Turin, Italy
| | - C Medana
- Department of Molecular Biotechnology and Health Sciences, University of Turin, Italy
| | - F Dal Bello
- Department of Molecular Biotechnology and Health Sciences, University of Turin, Italy
| | - G Boccuzzi
- Department of Medical Sciences, University of Turin, Italy
| | - M Collino
- Department of Drug Science and Technology, University of Turin, Italy
| | - M Aragno
- Department of Clinical and Biological Sciences, University of Turin, Italy
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Cheng Z, Oguejiofor CF, Swangchan-Uthai T, Carr S, Wathes DC. Relationships between Circulating Urea Concentrations and Endometrial Function in Postpartum Dairy Cows. Animals (Basel) 2015; 5:748-73. [PMID: 26479384 PMCID: PMC4598704 DOI: 10.3390/ani5030382] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 07/24/2015] [Accepted: 08/07/2015] [Indexed: 12/22/2022] Open
Abstract
Simple Summary Dairy cows fed high levels of protein to increase milk yield tend to have reduced fertility but the reasons behind this are unclear. Differing dietary protein levels are reflected in altered urea concentrations in both blood and other tissues including the uterus. We showed that the circulating urea concentration was highly correlated to changed expression levels of many genes in the endometrium shortly after calving. These were predominantly associated with tissue repair, innate immunity and lipid metabolism. A subsequent study found no effect of altered urea concentration on endometrial gene expression in vitro implying that the dietary influence is indirect. Abstract Both high and low circulating urea concentrations, a product of protein metabolism, are associated with decreased fertility in dairy cows through poorly defined mechanisms. The rate of involution and the endometrial ability to mount an adequate innate immune response after calving are both critical for subsequent fertility. Study 1 used microarray analysis to identify genes whose endometrial expression 2 weeks postpartum correlated significantly with the mean plasma urea per cow, ranging from 3.2 to 6.6 mmol/L. The biological functions of 781 mapped genes were analysed using Ingenuity Pathway Analysis. These were predominantly associated with tissue turnover (e.g., BRINP1, FOXG1), immune function (e.g., IL17RB, CRISPLD2), inflammation (e.g., C3, SERPINF1, SERPINF2) and lipid metabolism (e.g., SCAP, ACBD5, SLC10A). Study 2 investigated the relationship between urea concentration and expression of 6 candidate genes (S100A8, HSP5A, IGF1R, IL17RB, BRINP1, CRISPLD2) in bovine endometrial cell culture. These were treated with 0, 2.5, 5.0 or 7.5 mmol/L urea, equivalent to low, medium and high circulating values with or without challenge by bacterial lipopolysaccharide (LPS). LPS increased S100A8 expression as expected but urea treatment had no effect on expression of any tested gene. Examination of the genes/pathways involved suggests that plasma urea levels may reflect variations in lipid metabolism. Our results suggest that it is the effects of lipid metabolism rather than the urea concentration which probably alter the rate of involution and innate immune response, in turn influencing subsequent fertility.
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Affiliation(s)
- Zhangrui Cheng
- Department of Production and Population Health, Royal Veterinary College, North Mymms, Hertfordshire AL9 7TA, UK.
| | - Chike F Oguejiofor
- Department of Production and Population Health, Royal Veterinary College, North Mymms, Hertfordshire AL9 7TA, UK.
| | - Theerawat Swangchan-Uthai
- Department of Production and Population Health, Royal Veterinary College, North Mymms, Hertfordshire AL9 7TA, UK.
| | - Susan Carr
- Department of Production and Population Health, Royal Veterinary College, North Mymms, Hertfordshire AL9 7TA, UK.
| | - D Claire Wathes
- Department of Production and Population Health, Royal Veterinary College, North Mymms, Hertfordshire AL9 7TA, UK.
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Mao M, Lei H, Liu Q, Chen Y, Zhao L, Li Q, Luo S, Zuo Z, He Q, Huang W, Zhang N, Zhou C, Ruan XZ. Effects of miR-33a-5P on ABCA1/G1-mediated cholesterol efflux under inflammatory stress in THP-1 macrophages. PLoS One 2014; 9:e109722. [PMID: 25329888 PMCID: PMC4201478 DOI: 10.1371/journal.pone.0109722] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 09/04/2014] [Indexed: 01/23/2023] Open
Abstract
The present study is to investigate whether inflammatory cytokines inhibit ABCA1/ABCG1-mediated cholesterol efflux by regulating miR-33a-5P in THP-1 macrophages. We used interleukin-6 and tumor necrosis factor-alpha in the presence or absence of native low density lipoprotein (LDL) to stimulate THP-1 macrophages. THP-1 macrophages were infected by either control lentivirus vectors or lentivirus encoding miR-33a-5P or antisense miR-33a-5P. The effects of inflammatory cytokines, miR-33a-5P and antisense miR-33a-5P on intracellular lipids accumulation and intracellular cholesterol contents were assessed by oil red O staining and quantitative intracellular cholesterol assay. ApoA-I-mediated cholesterol efflux was examined using the fluorescent sterol (BODIPY-cholesterol). The gene and protein expressions of the molecules involved in cholesterol trafficking were examined using quantitative real-time polymerase chain reaction and Western blotting. Inflammatory cytokines or miR-33a-5P increased intracellular lipid accumulation and decreased apoA-I-mediated cholesterol efflux via decreasing the expression of ABCA1 and ABCG1 in the absence or presence of LDL in THP-1 macrophages. However, antisense miR-33a-5P reversed the effects of inflammatory cytokines on intracellular lipid accumulation, cholesterol efflux, and the expression of miR-33a-5P, ABCA1 and ABCG1 in the absence or presence of LDL in THP-1 macrophages. This study indicated that inflammatory cytokines inhibited ABCA1/ABCG1-mediated cholesterol efflux by up-regulating miR-33a-5P in THP-1 macrophages.
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Affiliation(s)
- Min Mao
- Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P.R. China
- Centre for Lipid Research, Key Laboratory of Metabolism on Lipid and Glucose, Chongqing Medical University, Chongqing, P.R. China
- Centre for Clinical Research, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P.R. China
| | - Han Lei
- Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P.R. China
- Centre for Lipid Research, Key Laboratory of Metabolism on Lipid and Glucose, Chongqing Medical University, Chongqing, P.R. China
- * E-mail:
| | - Qing Liu
- Centre for Clinical Research, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P.R. China
| | - Yaxi Chen
- Centre for Lipid Research, Key Laboratory of Metabolism on Lipid and Glucose, Chongqing Medical University, Chongqing, P.R. China
| | - Lei Zhao
- Centre for Lipid Research, Key Laboratory of Metabolism on Lipid and Glucose, Chongqing Medical University, Chongqing, P.R. China
| | - Qing Li
- Centre for Lipid Research, Key Laboratory of Metabolism on Lipid and Glucose, Chongqing Medical University, Chongqing, P.R. China
| | - Suxin Luo
- Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P.R. China
| | - Zhong Zuo
- Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P.R. China
| | - Quan He
- Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P.R. China
| | - Wei Huang
- Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P.R. China
| | - Nan Zhang
- Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P.R. China
| | - Chao Zhou
- Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P.R. China
- Centre for Lipid Research, Key Laboratory of Metabolism on Lipid and Glucose, Chongqing Medical University, Chongqing, P.R. China
| | - Xiong Z. Ruan
- Centre for Lipid Research, Key Laboratory of Metabolism on Lipid and Glucose, Chongqing Medical University, Chongqing, P.R. China
- John Moorhead Research Laboratory, Centre for Nephrology, University College London Medical School, Royal Free Campus, London, United Kingdom
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