1
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Castro CA, Buzinari TC, Lino RLB, Araújo HSSD, Aníbal FDF, Verzola RMM, Bagnato VS, Inada NM, Rodrigues GJ. Profile of IL-6 and TNF in Foam Cell Formation: An Improved Method Using Fluorescein Isothiocyanate (FITC) Probe. Arq Bras Cardiol 2022; 119:533-541. [PMID: 35946754 PMCID: PMC9563877 DOI: 10.36660/abc.20210682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 03/09/2022] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The formation of foam cells occurs due to the increase in low-density plasma lipoprotein (LDL) and dysregulation of inflammation, which is important for the development of atherosclerosis. OBJECTIVE To evaluate the profile of tumor necrosis factor-alpha (TNF-α) and Interleukin-6 (IL-6) in the existing foam cell formation method, optimizing this protocol. METHODS The LDL was isolated, oxidized, and labeled with a Fluorescein isothiocyanate (FITC) probe. Foam cells were generated from THP-1 human monocyte-derived cells and incubated in the absence (control) or presence of FITC-ox-LDL (10, 50, 100, 150, or 200 μg/mL), for 12, 24, 48, or 72 hours. The accumulated FITC-ox-LDL in the cell was quantified by microscopy. The enzyme-linked immunosorbent assay was evaluated to quantify the IL-6 and TNF-α, with p < 0.05 considered significant. RESULTS All the FITC-ox-LDL concentrations tested showed a higher fluorescence when compared to the control, showing a greater accumulation of lipoprotein in cells. The higher the concentration of FITC-ox-LDL, the greater the production of TNF-α and IL-6. The production of IL-6 by foam cells was detected up to the value of 150 µg/mL of the maximum stimulus for LDL. Concentrations above 50 μg/mL LDL stimulated greater release of TNF-α compared to control. CONCLUSIONS Our model contributes to the understanding of the release of IL-6 and TNF-α in response to different concentrations of ox-LDL, using an optimized method for the formation of foam cells.
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Affiliation(s)
- Cynthia Aparecida Castro
- Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP - Brasil.,Departamento de Morfologia e Patologia - Universidade Federal de São Carlos, São Carlos, SP - Brasil
| | - Tereza Cristina Buzinari
- Departamento de Ciências Fisiológicas - Universidade Federal de São Carlos, São Carlos, SP - Brasil
| | | | | | | | | | | | - Natalia Mayumi Inada
- Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP - Brasil
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2
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Li J, Meng Q, Fu Y, Yu X, Ji T, Chao Y, Chen Q, Li Y, Bian H. Novel insights: Dynamic foam cells derived from the macrophage in atherosclerosis. J Cell Physiol 2021; 236:6154-6167. [PMID: 33507545 DOI: 10.1002/jcp.30300] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/22/2020] [Accepted: 01/15/2021] [Indexed: 12/12/2022]
Abstract
Atherosclerosis can be regarded as a chronic disease derived from the interaction between disordered lipoproteins and an unsuitable immune response. The evolution of foam cells is not only a significant pathological change in the early stage of atherosclerosis but also a key stage in the occurrence and development of atherosclerosis. The formation of foam cells is mainly caused by the imbalance among lipids uptake, lipids treatment, and reverse cholesterol transport. Although a large number of studies have summarized the source of foam cells and the mechanism of foam cells formation, we propose a new idea about foam cells in atherosclerosis. Rather than an isolated microenvironment, the macrophage multiple lipid uptake pathways, lipid internalization, lysosome, mitochondria, endoplasmic reticulum, neutral cholesterol ester hydrolase (NCEH), acyl-coenzyme A-cholesterol acyltransferase (ACAT), and reverse cholesterol transport are mutually influential, and form a dynamic process under multi-factor regulation. The macrophage takes on different uptake lipid statuses depending on multiple uptake pathways and intracellular lipids, lipid metabolites versus pro-inflammatory factors. Except for NCEH and ACAT, the lipid internalization of macrophages also depends on multicellular organelles including the lysosome, mitochondria, and endoplasmic reticulum, which are associated with each other. A dynamic balance between esterification and hydrolysis of cholesterol for macrophages is essential for physiology and pathology. Therefore, we propose that the foam cell in the process of atherosclerosis may be dynamic under multi-factor regulation, and collate this study to provide a holistic and dynamic idea of the foam cell.
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Affiliation(s)
- Jun Li
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China
| | - Qinghai Meng
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China
| | - Yu Fu
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China
| | - Xichao Yu
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China
| | - Tingting Ji
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China
| | - Ying Chao
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China
| | - Qi Chen
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China
| | - Yu Li
- School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Huimin Bian
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China.,Jiangsu Key Laboratory of Therapeutic Material of Chinese Medicine, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China
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3
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Haritha VH, George A, Shaji BV, Anie Y. NET-associated citrullinated histones promote LDL aggregation and foam cell formation in vitro. Exp Cell Res 2020; 396:112320. [PMID: 33058833 DOI: 10.1016/j.yexcr.2020.112320] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/06/2020] [Accepted: 10/08/2020] [Indexed: 11/16/2022]
Abstract
Neutrophils have been recently identified in the atherosclerotic lesion and they can release neutrophil extracellular trap (NET) under the pro-inflammatory conditions prevailing in the lesion. Citrullinated histones (Cit-histones) are the major type of citrullinated proteins associated with NET release. Since elevated levels of citrullinated proteins have been detected in inflammatory diseases including atherosclerosis, this study analysed the role played by NET and Cit-histones in different atherogenic events in vitro. First, neutrophil recruitment and NET release in the presence of low-density lipoprotein (LDL) and oxidised LDL (Ox-LDL) were analysed by Boyden's chamber method and microscopy respectively. Then, LDL oxidation and LDL aggregation in the presence of NET and Cit-histones were analysed spectroscopically. Foam cell formation in the presence of NET or Cit-histone was studied by both microscopic and spectroscopic methods. While neutrophil recruitment was facilitated by Ox-LDL and not by LDL, the extent of NET release was significantly increased in the presence of both LDL and Ox-LDL. In the presence of NET, LDL oxidation, aggregation and foam cell formation were found to be increased. Cit-histones were found to accelerate LDL aggregation and foam cell formation at higher citrulline levels. Altogether, the results suggest that both NET and NET-associated Cit-histone released at the lesion can play major roles as pro-atherogenic mediators. Inhibiting the action of NET or Cit-histone would, therefore, be beneficial in slowing down atherosclerotic progression.
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Affiliation(s)
- V H Haritha
- School of Biosciences, Mahatma Gandhi University, Kottayam, Kerala, 686560, India.
| | - Anjana George
- School of Biosciences, Mahatma Gandhi University, Kottayam, Kerala, 686560, India.
| | - Binchu V Shaji
- School of Biosciences, Mahatma Gandhi University, Kottayam, Kerala, 686560, India.
| | - Y Anie
- School of Biosciences, Mahatma Gandhi University, Kottayam, Kerala, 686560, India.
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4
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Vedder VL, Aherrahrou Z, Erdmann J. Dare to Compare. Development of Atherosclerotic Lesions in Human, Mouse, and Zebrafish. Front Cardiovasc Med 2020; 7:109. [PMID: 32714944 PMCID: PMC7344238 DOI: 10.3389/fcvm.2020.00109] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 05/26/2020] [Indexed: 12/19/2022] Open
Abstract
Cardiovascular diseases, such as atherosclerosis, are the leading cause of death worldwide. Although mice are currently the most commonly used model for atherosclerosis, zebrafish are emerging as an alternative, especially for inflammatory and lipid metabolism studies. Here, we review the history of in vivo atherosclerosis models and highlight the potential for future studies on inflammatory responses in lipid deposits in zebrafish, based on known immune reactions in humans and mice, in anticipation of new zebrafish models with more advanced atherosclerotic plaques.
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Affiliation(s)
- Viviana L Vedder
- Institute for Cardiogenetics, University of Lübeck, Lübeck, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Lübeck, Germany.,University Heart Centre Lübeck, Lübeck, Germany
| | - Zouhair Aherrahrou
- Institute for Cardiogenetics, University of Lübeck, Lübeck, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Lübeck, Germany.,University Heart Centre Lübeck, Lübeck, Germany
| | - Jeanette Erdmann
- Institute for Cardiogenetics, University of Lübeck, Lübeck, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Lübeck, Germany.,University Heart Centre Lübeck, Lübeck, Germany
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5
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Zhang X, Xue C, Xu Q, Zhang Y, Li H, Li F, Liu Y, Guo C. Caprylic acid suppresses inflammation via TLR4/NF-κB signaling and improves atherosclerosis in ApoE-deficient mice. Nutr Metab (Lond) 2019; 16:40. [PMID: 31182969 PMCID: PMC6555760 DOI: 10.1186/s12986-019-0359-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Accepted: 05/01/2019] [Indexed: 12/23/2022] Open
Abstract
Background As reported previously by our group, medium-chain triglycerides can ameliorate atherosclerosis. Given that TLR4 is closely related to atherosclerosis, we hypothesized herein that caprylic acid (C8:0) would suppress inflammation via TLR4/NF-κB signaling and further promote the amelioration of atherosclerosis in apoE- deficient (apoE-/-) mice. Methods Fifty 6-week male apoE-/- mice were randomly allocated into five diet groups: a high-fat diet (HFD) without or with 2% caprylic acid (C8:0), capric acid (C10:0), stearic acid (C18:0), or linolenic acid (C18:3). RAW246.7 cells were treated with caprylic acid (C8:0), docosahexenoic acid (DHA), palmitic acid (C16:0), and lipopolysaccharide (LPS) with or without TLR4 knock-down (TLR4-KD). The serum lipid profiles, inflammatory biomolecules, and mRNA and protein expression levels were measured. Atherosclerotic lesions that occurred in the aorta and aortic sinuses were evaluated and quantified. Results Our results indicated that C8:0 reduced body fat, improved the lipid profiles, suppressed inflammatory cytokine production, downregulated aortic TLR4, MyD88, NF-κB, TNF-α, IKKα, and IKKβ mRNA expression, and alleviated atherosclerosis in the apoE-/- mice (P < 0.05). In RAW 264.7 cells, C8:0 diminished the inflammatory response and both mRNA and protein expression of TLR4, MyD88, NF-κB, and TNF-α compared to those in the LPS and C16:0 groups (P < 0.05). However, in the TLR4-KD RAW 264.7 cells, C8:0 significantly upregulated NF-κB mRNA and protein expression compared to those in the C16:0 and DHA groups. Conclusions These results suggest that C8:0 functions via TLR4/NF-κB signaling to improve the outcomes of apoE-/- mice through suppressing inflammation and ameliorating atherosclerosis. Thus, C8:0 may represent as a promising nutrient against chronic inflammatory diseases.
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Affiliation(s)
- Xinsheng Zhang
- Department of Nutrition, Tianjin Institute of Environmental & Operational Medicine, Tianjin, 300050 China.,2Department of Nutrition, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 China
| | - Changyong Xue
- 2Department of Nutrition, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 China
| | - Qing Xu
- 2Department of Nutrition, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 China
| | - Yong Zhang
- 2Department of Nutrition, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 China
| | - Huizi Li
- 3Department of Nutrition, PLA Rocket Force Characteristic Medical Center, Beijing, 100088 China
| | - Feng Li
- 4Department of Nutrition, Air Force Medical Center, PLA, Beijing, 100142 China
| | - Yinghua Liu
- 2Department of Nutrition, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 China
| | - Changjiang Guo
- Department of Nutrition, Tianjin Institute of Environmental & Operational Medicine, Tianjin, 300050 China
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6
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Yu LE, Lai CL, Lee CT, Wang JY. Highly electronegative low-density lipoprotein L5 evokes microglial activation and creates a neuroinflammatory stress via Toll-like receptor 4 signaling. J Neurochem 2017; 142:231-245. [PMID: 28444734 DOI: 10.1111/jnc.14053] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 03/30/2017] [Accepted: 04/19/2017] [Indexed: 12/23/2022]
Abstract
Atherogenic risk factors, such as hypercholesterolemia, are associated with increased risk of neurodegeneration, especially Alzheimer's dementia. Human plasma electronegative low-density lipoprotein [LDL(-)], especially L5, may serve as an important contributing factor. L5 promoting an inflammatory action in atherosclerosis has been extensively studied. However, the role of L5 in inducing neuroinflammation remains unknown. Here, we examined the impact of L5 on immune activation and cell viability in cultured BV-2 microglia. BV-2 cells treated with lipopolysaccharide or human LDLs (L1, L5, or oxLDL) were subjected to molecular/biochemical assays for measuring microglial activation, levels of inflammatory factors, and cell survival. A transwell BV-2/N2a co-culture was used to assess N2a cell viability following BV-2 cell exposure to L5. We found that L5 enables the activation of microglia and elicits an inflammatory response, as evidenced by increased oxygen/nitrogen free radicals (nitric oxide, reactive oxygen species, and peroxides), elevated tumor necrosis factor-α levels, decreased basal interleukin-10 levels, and augmented production of pro-inflammatory proteins (inducible nitric oxide synthase and cyclooxygenase-2). L5 also triggered BV-2 cell death primarily via apoptosis. These effects were markedly disrupted by the application of signaling pathway inhibitors, thus demonstrating that L5 interacts with Toll-like receptor 4 to modulate multiple pathways, including MAPKs, PI3K/Akt, and NF-κB. Decreased N2a cell viability in a transwell co-culture was mainly ascribed to L5-induced BV-2 cell activation. Together, our data suggest that L5 creates a neuroinflammatory stress via microglial Toll-like receptor 4, thereby leading to the death of BV-2 microglia and coexistent N2a cells. Atherogenic L5 possibly contributes to neuroinflammation-related neurodegeneration.
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Affiliation(s)
- Liang-En Yu
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chiou-Lian Lai
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Neurology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Ching-Tien Lee
- Department of Nursing, Hsin-Sheng College of Medical Care and Management, Taoyuan, Taiwan
| | - Jiz-Yuh Wang
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
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7
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Nègre-Salvayre A, Augé N, Camaré C, Bacchetti T, Ferretti G, Salvayre R. Dual signaling evoked by oxidized LDLs in vascular cells. Free Radic Biol Med 2017; 106:118-133. [PMID: 28189852 DOI: 10.1016/j.freeradbiomed.2017.02.006] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Revised: 01/30/2017] [Accepted: 02/02/2017] [Indexed: 12/12/2022]
Abstract
The oxidative theory of atherosclerosis relies on the modification of low density lipoproteins (LDLs) in the vascular wall by reactive oxygen species. Modified LDLs, such as oxidized LDLs, are thought to participate in the formation of early atherosclerotic lesions (accumulation of foam cells and fatty streaks), whereas their role in advanced lesions and atherothrombotic events is more debated, because antioxidant supplementation failed to prevent coronary disease events and mortality in intervention randomized trials. As oxidized LDLs and oxidized lipids are present in atherosclerotic lesions and are able to trigger cell signaling on cultured vascular cells and macrophages, it has been proposed that they could play a role in atherogenesis and atherosclerotic vascular remodeling. Oxidized LDLs exhibit dual biological effects, which are dependent on extent of lipid peroxidation, nature of oxidized lipids (oxidized phospholipids, oxysterols, malondialdehyde, α,β-unsaturated hydroxyalkenals), concentration of oxidized LDLs and uptake by scavenger receptors (e.g. CD36, LOX-1, SRA) that signal through different transduction pathways. Moderate concentrations of mildly oxidized LDLs are proinflammatory and trigger cell migration and proliferation, whereas higher concentrations induce cell growth arrest and apoptosis. The balance between survival and apoptotic responses evoked by oxidized LDLs depends on cellular systems that regulate the cell fate, such as ceramide/sphingosine-1-phosphate rheostat, endoplasmic reticulum stress, autophagy and expression of pro/antiapoptotic proteins. In vivo, the intimal concentration of oxidized LDLs depends on the influx (hypercholesterolemia, endothelial permeability), residence time and lipid composition of LDLs, oxidative stress intensity, induction of defense mechanisms (antioxidant systems, heat shock proteins). As a consequence, the local cellular responses to oxidized LDLs may stimulate inflammatory or anti-inflammatory pathways, angiogenic or antiangiogenic responses, survival or apoptosis, thereby contributing to plaque growth, instability, complication (intraplaque hemorrhage, proteolysis, calcification, apoptosis) and rupture. Finally, these dual properties suggest that oxLDLs could be implicated at each step of atherosclerosis development, from early fatty streaks to advanced lesions, depending on the nature and concentration of their oxidized lipid content.
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Affiliation(s)
| | | | - Caroline Camaré
- Inserm UMR-1048, France; University of Toulouse, Faculty of Medicine, Biochemistry Dept, Toulouse, France; CHU Toulouse, Rangueil, Toulouse, France
| | | | | | - Robert Salvayre
- Inserm UMR-1048, France; University of Toulouse, Faculty of Medicine, Biochemistry Dept, Toulouse, France; CHU Toulouse, Rangueil, Toulouse, France.
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8
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Howard JC, Florentinus-Mefailoski A, Bowden P, Trimble W, Grinstein S, Marshall JG. OxLDL receptor chromatography from live human U937 cells identifies SYK(L) that regulates phagocytosis of oxLDL. Anal Biochem 2016; 513:7-20. [PMID: 27510553 DOI: 10.1016/j.ab.2016.07.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Revised: 06/21/2016] [Accepted: 07/19/2016] [Indexed: 11/16/2022]
Abstract
The binding and activation of macrophages by microscopic aggregates of oxLDL in the intima of the arteries may be an important step towards atherosclerosis leading to heart attack and stroke. Microbeads coated with oxLDL were used to activate, capture and isolate the oxLDL receptor complex from the surface of live cells. Analysis of the resulting tryptic peptides by liquid chromatography and tandem mass spectrometry revealed the Spleen Tyrosine Kinase (SYK), and many of SYK's known interaction network including Fc receptors (FCGR2A, FCER1G and FCGR1A) Toll receptor 4 (TLR4), receptor kinases like EGFRs, as well as RNA binding and metabolism proteins. High-intensity precursor ions (∼9*E3 to 2*E5 counts) were correlated to peptides and specific phosphopeptides from long isoform of SYK (SYK-L) by the SEQUEST, OMSSA and X!TANDEM algorithms. Peptides or phosphopeptides from SYK were observed with the oxLDL-microbeads. Pharmacological inhibitors of SYK activity significantly reduced the engulfment of oxLDL microbeads in the presence of serum factors, but had little effect on IgG phagocytosis. Anti SYK siRNA regulated oxLD engulfment in the context of serum factors and or SYK-L siRNA significantly inhibited engulfment of oxLDL microbeads, but not IgG microbeads.
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Affiliation(s)
- Jeffrey C Howard
- Department of Chemistry and Biology, Ryerson University, Toronto, ON M5B 2K3, Canada
| | | | - Peter Bowden
- Department of Chemistry and Biology, Ryerson University, Toronto, ON M5B 2K3, Canada
| | - William Trimble
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - John G Marshall
- Department of Chemistry and Biology, Ryerson University, Toronto, ON M5B 2K3, Canada.
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9
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Manso-Calderón R, González-Sarmiento R. Genetic susceptibility to vascular cognitive impairment: a pathophysiological view. FUTURE NEUROLOGY 2016. [DOI: 10.2217/fnl-2016-0002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The heterogeneity of the vascular cognitive impairment (VCI) creates challenges for research on its genetic basis and pathophysiology. Despite well-known monogenic forms may be useful to understand some pathogenic mechanisms leading to VCI, most of VCIs are sporadic disorders resulting from the interaction between environmental, vascular and genetic factors. Genetic investigation for VCI may encompass both candidate genes that affect critical biological processes to VCI and common and rare genetic variants identified across the entire genome study technology, thereby enabling us to confirm or expose new biological mechanisms in VCI and develop new therapeutic and preventive approaches. Notwithstanding genetic susceptibility to VCI remains largely unknown owing to methodological issues. Collaborative efforts emerge as an interesting strategy to overcome these problems.
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Affiliation(s)
- Raquel Manso-Calderón
- Department of Neurology, University Hospital of Salamanca, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), University of Salamanca-CSIC-SACYL, Salamanca, Spain
| | - Rogelio González-Sarmiento
- Institute of Biomedical Research of Salamanca (IBSAL), University of Salamanca-CSIC-SACYL, Salamanca, Spain
- Molecular Medicine Unit, Department of Medicine & Institute of Molecular & Cellular Biology of Cancer (IBMCC). University of Salamanca-CSIC, Salamanca, Spain
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10
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Qin L, Zhu N, Ao BX, Liu C, Shi YN, Du K, Chen JX, Zheng XL, Liao DF. Caveolae and Caveolin-1 Integrate Reverse Cholesterol Transport and Inflammation in Atherosclerosis. Int J Mol Sci 2016; 17:429. [PMID: 27011179 PMCID: PMC4813279 DOI: 10.3390/ijms17030429] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 03/16/2016] [Accepted: 03/16/2016] [Indexed: 01/18/2023] Open
Abstract
Lipid disorder and inflammation play critical roles in the development of atherosclerosis. Reverse cholesterol transport is a key event in lipid metabolism. Caveolae and caveolin-1 are in the center stage of cholesterol transportation and inflammation in macrophages. Here, we propose that reverse cholesterol transport and inflammation in atherosclerosis can be integrated by caveolae and caveolin-1.
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Affiliation(s)
- Li Qin
- School of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China.
| | - Neng Zhu
- Department of Urology, The First Hospital of Hunan University of Chinese Medicine, Changsha 410208, China.
| | - Bao-Xue Ao
- School of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China.
| | - Chan Liu
- School of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China.
| | - Ya-Ning Shi
- School of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China.
| | - Ke Du
- School of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China.
| | - Jian-Xiong Chen
- School of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China.
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, School of Medicine, Jackson, MS 39216, USA.
| | - Xi-Long Zheng
- School of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China.
- Department of Biochemistry & Molecular Biology, the Libin Cardiovascular Institute of Alberta, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada.
| | - Duan-Fang Liao
- School of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China.
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11
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The Toll of Vascular Insufficiency: Implications for the Management of Peripheral Arterial Disease. J Immunol Res 2016; 2016:8249015. [PMID: 26998496 PMCID: PMC4779544 DOI: 10.1155/2016/8249015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 01/19/2016] [Accepted: 01/21/2016] [Indexed: 01/17/2023] Open
Abstract
Peripheral artery disease (PAD) can result in limb loss within six months of diagnosis in a subset of patients who cannot undergo endovascular or surgical revascularization yet continues to maintain a marginal position in cardiovascular research. While a body of literature continues to grow describing the role of danger signaling and innate immunity in cardiac biology, the role of these pathways in the ischemic myopathy associated with PAD has not been extensively studied. The following report will review the current literature on the role of Toll-like receptor (TLR) signaling in cardiovascular biology as well as in nonischemic myopathy. While attenuation of TLR signaling has not been shown to be clinically useful in the treatment of infectious inflammation, it may show promise in the management of severe arterial insufficiency.
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12
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Al-Sharea A, Lee MKS, Moore XL, Fang L, Sviridov D, Chin-Dusting J, Andrews KL, Murphy AJ. Native LDL promotes differentiation of human monocytes to macrophages with an inflammatory phenotype. Thromb Haemost 2015; 115:762-72. [PMID: 26676845 DOI: 10.1160/th15-07-0571] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 11/13/2015] [Indexed: 11/05/2022]
Abstract
Recruitment of monocytes in atherosclerosis is dependent upon increased levels of plasma lipoproteins which accumulate in the blood vessel wall. The extracellular milieu can influence the phenotype of monocyte subsets (classical: CD14++CD16-, intermediate: CD14+CD16+ and non-classical: CD14dimCD16++) and macrophages (M1 or M2) and consequently the initiation, progression and/or regression of atherosclerosis. However, it is not known what effect lipoproteins, in particular native low-density lipoproteins (nLDL), have on the polarisation of monocyte-derived macrophages. Monocytes were differentiated into macrophages in the presence of nLDL. nLDL increased gene expression of the inflammatory cytokines TNFα and IL-6 in macrophages polarised towards the M1 phenotype while decreasing the M2 surface markers, CD206 and CD200R and the anti-inflammatory cytokines TGFβ and IL-10. Compared to the classical and intermediate subsets, the non-classical subset-derived macrophages had a reduced ability to respond to M1 stimuli (LPS and IFNγ). nLDL enhanced the TNFα and IL-6 gene expression in macrophages from all monocyte subsets, indicating an inflammatory effect of nLDL. Further, the classical and intermediate subsets both responded to M2 stimuli (IL-4) with upregulation of TGFβ and SR-B1 mRNA; an effect, which was reduced by nLDL. In contrast, the non-classical subset failed to respond to IL-4 or nLDL, suggesting it may be unable to polarise into M2 macrophages. Our data suggests that monocyte interaction with nLDL significantly affects macrophage polarisation and that this interaction appears to be subset dependent.
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Affiliation(s)
| | | | | | | | | | | | | | - Andrew J Murphy
- Dr. Andrew J. Murphy, Baker IDI Heart and Diabetes Institute, PO Box 6492, St Kilda Road central, Melbourne, VIC 8008, Australia, Tel.: +61 3 8532 1292, Fax: +61 3 8532 1100, E-mail:
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13
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Gargiulo S, Gamba P, Testa G, Rossin D, Biasi F, Poli G, Leonarduzzi G. Relation between TLR4/NF-κB signaling pathway activation by 27-hydroxycholesterol and 4-hydroxynonenal, and atherosclerotic plaque instability. Aging Cell 2015; 14:569-81. [PMID: 25757594 PMCID: PMC4531071 DOI: 10.1111/acel.12322] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/03/2015] [Indexed: 01/22/2023] Open
Abstract
It is now thought that atherosclerosis, although due to increased plasma lipids, is mainly the consequence of a complicated inflammatory process, with immune responses at the different stages of plaque development. Increasing evidence points to a significant role of Toll-like receptor 4 (TLR4), a key player in innate immunity, in the pathogenesis of atherosclerosis. This study aimed to determine the effects on TLR4 activation of two reactive oxidized lipids carried by oxidized low-density lipoproteins, the oxysterol 27-hydroxycholesterol (27-OH) and the aldehyde 4-hydroxynonenal (HNE), both of which accumulate in atherosclerotic plaques and play a key role in the pathogenesis of atherosclerosis. Secondarily, it examined their potential involvement in mediating inflammation and extracellular matrix degradation, the hallmarks of high-risk atherosclerotic unstable plaques. In human promonocytic U937 cells, both 27-OH and HNE were found to enhance cell release of IL-8, IL-1β, and TNF-α and to upregulate matrix metalloproteinase-9 (MMP-9) via TLR4/NF-κB-dependent pathway; these actions may sustain the inflammatory response and matrix degradation that lead to atherosclerotic plaque instability and to their rupture. Using specific antibodies, it was also demonstrated that these inflammatory cytokines increase MMP-9 upregulation, thus enhancing the release of this matrix-degrading enzyme by macrophage cells and contributing to plaque instability. These innovative results suggest that, by accumulating in atherosclerotic plaques, the two oxidized lipids may contribute to plaque instability and rupture. They appear to do so by sustaining the release of inflammatory molecules and MMP-9 by inflammatory and immune cells, for example, macrophages, through activation of TLR4 and its NF-κB downstream signaling.
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Affiliation(s)
- Simona Gargiulo
- Department of Clinical and Biological Sciences School of Medicine University of Turin, Orbassano Turin Italy
| | - Paola Gamba
- Department of Clinical and Biological Sciences School of Medicine University of Turin, Orbassano Turin Italy
| | - Gabriella Testa
- Department of Clinical and Biological Sciences School of Medicine University of Turin, Orbassano Turin Italy
| | - Daniela Rossin
- Department of Clinical and Biological Sciences School of Medicine University of Turin, Orbassano Turin Italy
| | - Fiorella Biasi
- Department of Clinical and Biological Sciences School of Medicine University of Turin, Orbassano Turin Italy
| | - Giuseppe Poli
- Department of Clinical and Biological Sciences School of Medicine University of Turin, Orbassano Turin Italy
| | - Gabriella Leonarduzzi
- Department of Clinical and Biological Sciences School of Medicine University of Turin, Orbassano Turin Italy
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Jia SJ, Niu PP, Cong JZ, Zhang BK, Zhao M. TLR4 signaling: A potential therapeutic target in ischemic coronary artery disease. Int Immunopharmacol 2014; 23:54-9. [DOI: 10.1016/j.intimp.2014.08.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 08/06/2014] [Accepted: 08/13/2014] [Indexed: 01/12/2023]
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Potential cardiovascular risk protection of bilirubin in end-stage renal disease patients under hemodialysis. BIOMED RESEARCH INTERNATIONAL 2014; 2014:175286. [PMID: 25276769 PMCID: PMC4174976 DOI: 10.1155/2014/175286] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 08/19/2014] [Indexed: 12/18/2022]
Abstract
We evaluated the potential cardiovascular risk protection of bilirubin in hemodialysis (HD) patients. An enlarged set of studies were evaluated in 191 HD patients, including hematological study, lipid profile, iron metabolism, nutritional, inflammatory markers, and dialysis adequacy. The TA duplication screening in the UDP-glucuronosyltransferase 1 A1 (UGT1A1) promoter region was also performed. The UGT1A1 genotype frequencies in HD patients were 49.2%, 42.4%, and 8.4% for 6/6, 6/7, and 7/7 genotypes, respectively. Although no difference was found in UGT1A1 genotype distribution between the three tertiles of bilirubin, significant differences were found with increasing bilirubin levels, namely, a decrease in platelet, leukocyte, and lymphocyte counts, transferrin, oxidized low-density lipoprotein (ox-LDL), ox-LDL/low-density lipoprotein cholesterol ratio, apolipoprotein (Apo) A, Apo B, and interleukin-6 serum levels and a significant increased concentration of hemoglobin, hematocrit, erythrocyte count, iron, transferrin saturation, Apo A/Apo B ratio, adiponectin, and paraoxonase 1 serum levels. After adjustment for age these results remained significant. Our data suggest that higher bilirubin levels are associated with beneficial effects in HD patients, by improving lipid profile and reducing the inflammatory grade, which might contribute to increase in iron availability. These results suggest a potential cardiovascular risk protection of bilirubin in HD patients.
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Lugrin J, Rosenblatt-Velin N, Parapanov R, Liaudet L. The role of oxidative stress during inflammatory processes. Biol Chem 2014; 395:203-30. [PMID: 24127541 DOI: 10.1515/hsz-2013-0241] [Citation(s) in RCA: 430] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 10/09/2013] [Indexed: 12/22/2022]
Abstract
Abstract The production of various reactive oxidant species in excess of endogenous antioxidant defense mechanisms promotes the development of a state of oxidative stress, with significant biological consequences. In recent years, evidence has emerged that oxidative stress plays a crucial role in the development and perpetuation of inflammation, and thus contributes to the pathophysiology of a number of debilitating illnesses, such as cardiovascular diseases, diabetes, cancer, or neurodegenerative processes. Oxidants affect all stages of the inflammatory response, including the release by damaged tissues of molecules acting as endogenous danger signals, their sensing by innate immune receptors from the Toll-like (TLRs) and the NOD-like (NLRs) families, and the activation of signaling pathways initiating the adaptive cellular response to such signals. In this article, after summarizing the basic aspects of redox biology and inflammation, we review in detail the current knowledge on the fundamental connections between oxidative stress and inflammatory processes, with a special emphasis on the danger molecule high-mobility group box-1, the TLRs, the NLRP-3 receptor, and the inflammasome, as well as the transcription factor nuclear factor-κB.
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Ayyappan JP, Abraham A. Targeting TLR4/MAPKs signaling pathway: A better option for therapeutic inhibition of atherosclerosis. World J Immunol 2014; 4:116-121. [DOI: 10.5411/wji.v4.i2.116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 05/10/2014] [Accepted: 06/27/2014] [Indexed: 02/05/2023] Open
Abstract
Cardiovascular diseases, especially atherosclerosis, found to be the dreadful diseases worldwide. There are diverse pathways associated with the progression of atherosclerosis. One of the important signaling pathways to target atherosclerotic plaque rupture is toll-like receptor 4 (TLR4) Pathway. Several studies are available for illustrating the role of TLR4 in health and diseases. Different types of immune cell are activated in atherosclerosis but primary cells that are activated by the TLR4 signaling are macrophages and endothelial cells. Mechanisms by which macrophages uptake lipids are diverse and it is very important to target signaling pathway responsible for controlling foam cell formation. The process of macrophages transformed foam cell formation is the critical event in progression of atherosclerotic lesion and TLR4 found to have actively participate in the event through mitogen activated protein kinases (MAPKs) activation. The activation of MAPKs signaling pathway leads to the accumulation of cholesterol in the macrophages and also contribute to the dissociation of IκB and the nuclear translocation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) p65 subunit, thereby activating key inflammatory cascade activation by MAPKs/NF-κB signaling pathway to induce toxicity by activating different inflammatory parameters. Hence, the review focussed on exploring the role of TLR4/MAPKs signaling pathway for the therapeutic inhibition of atherosclerosis.
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Fornoni A, Merscher S, Kopp JB. Lipid biology of the podocyte--new perspectives offer new opportunities. Nat Rev Nephrol 2014; 10:379-88. [PMID: 24861084 DOI: 10.1038/nrneph.2014.87] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In the past 15 years, major advances have been made in understanding the role of lipids in podocyte biology. First, susceptibility to focal segmental glomerulosclerosis (FSGS) and glomerular disease is associated with an APOL1 sequence variant, is expressed in podocytes and encodes apolipoprotein L1, an important component of HDL. Second, acid sphingomyelinase-like phosphodiesterase 3b encoded by SMPDL3b has a role in the conversion of sphingomyelin to ceramide and its levels are reduced in renal biopsy samples from patients with recurrent FSGS. Furthermore, decreased SMPDL3b expression is associated with increased susceptibility of podocytes to injury after exposure to sera from these patients. Third, in many individuals with membranous nephropathy, autoantibodies against the phospholipase A2 (PLA2) receptor, which is expressed in podocytes, have been identified. Whether these autoantibodies affect the activity of PLA2, which liberates arachidonic acid from glycerophospholipids and modulates podocyte function, is unknown. Fourth, clinical and experimental evidence support a role for ATP-binding cassette sub-family A member 1-dependent cholesterol efflux, free fatty acids and glycerophospolipids in the pathogenesis of diabetic kidney disease. An improved understanding of lipid biology in podocytes might provide insights to develop therapeutic targets for primary and secondary glomerulopathies.
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Affiliation(s)
- Alessia Fornoni
- Peggy and Harold Katz Family Drug Discovery Center, Division of Nephrology and Hypertension, University of Miami Miller School of Medicine, 1580 North West 10th Avenue, Miami, FL 33136, USA
| | - Sandra Merscher
- Peggy and Harold Katz Family Drug Discovery Center, Division of Nephrology and Hypertension, University of Miami Miller School of Medicine, 1580 North West 10th Avenue, Miami, FL 33136, USA
| | - Jeffrey B Kopp
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, 10 Center Drive, 3N116 Bethesda, MD 20892-1268, USA
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Fang L, Liu C, Miller YI. Zebrafish models of dyslipidemia: relevance to atherosclerosis and angiogenesis. Transl Res 2014; 163:99-108. [PMID: 24095954 PMCID: PMC3946603 DOI: 10.1016/j.trsl.2013.09.004] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 09/07/2013] [Accepted: 09/10/2013] [Indexed: 01/07/2023]
Abstract
Lipid and lipoprotein metabolism in zebrafish and in humans are remarkably similar. Zebrafish express all major nuclear receptors, lipid transporters, apolipoproteins and enzymes involved in lipoprotein metabolism. Unlike mice, zebrafish express cetp and the Cetp activity is detected in zebrafish plasma. Feeding zebrafish a high cholesterol diet, without any genetic intervention, results in significant hypercholesterolemia and robust lipoprotein oxidation, making zebrafish an attractive animal model to study mechanisms relevant to early development of human atherosclerosis. These studies are facilitated by the optical transparency of zebrafish larvae and the availability of transgenic zebrafish expressing fluorescent proteins in endothelial cells and macrophages. Thus, vascular processes can be monitored in live animals. In this review article, we discuss recent advances in using dyslipidemic zebrafish in atherosclerosis-related studies. We also summarize recent work connecting lipid metabolism with regulation of angiogenesis, the work that considerably benefited from using the zebrafish model. These studies uncovered the role of aibp, abca1, abcg1, mtp, apoB, and apoC2 in regulation of angiogenesis in zebrafish and paved the way for future studies in mammals, which may suggest new therapeutic approaches to modulation of excessive or diminished angiogenesis contributing to the pathogenesis of human disease.
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Affiliation(s)
- Longhou Fang
- Department of Medicine, University of California, San Diego, La Jolla, Calif
| | - Chao Liu
- Department of Medicine, University of California, San Diego, La Jolla, Calif
| | - Yury I Miller
- Department of Medicine, University of California, San Diego, La Jolla, Calif.
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20
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Feng X, Yuan Y, Wang C, Feng J, Yuan Z, Zhang X, Sui W, Hu P, Zheng P, Ye J. Autophagy involved in lipopolysaccharide-induced foam cell formation is mediated by adipose differentiation-related protein. Lipids Health Dis 2014; 13:10. [PMID: 24405744 PMCID: PMC3896829 DOI: 10.1186/1476-511x-13-10] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 01/07/2014] [Indexed: 02/02/2023] Open
Abstract
Background Autophagy is an essential process for breaking down macromolecules and aged/damaged cellular organelles to maintain cellular energy balance and cellular nutritional status. The idea that autophagy regulates lipid metabolism is an emerging concept with important implications for atherosclerosis. However, the potential role of autophagy and its relationship with lipid metabolism in foam cell formation remains unclear. In this study, we found that autophagy was involved in the lipopolysaccharide (LPS)-induced the formation of foam cells and was at least partially dependent on adipose differentiation-related protein (ADRP). Method Foam cell formation was evaluated by Oil red O staining. Autophagic activity was determined by immunofluorescence and Western blotting. ADRP gene expression of ADRP was examined by real-time PCR (RT-PCR). The protein expression of ADRP and LC3 was measured using Western blotting analysis. Intracellular cholesterol and triglyceride levels in foam cells were quantitatively measured by enzymatic colorimetric assays. Results LPS promoted foam cell formation by inducing lipid accumulation in macrophages. The activation of autophagy with rapamycin (Rap) decreased intracellular cholesterol and triglyceride levels, whereas the inhibition of autophagy with 3-methyladenine (3MA) enhanced the accumulation of lipid droplets. Overexpression of ADRP alone increased the formation of foam cells and consequently autophagic activity. In contrast, the inhibitory effects of ADRP activity with siRNA suppressed the activation of autophagy. Taken together, we propose a novel role for ADRP in the regulation of macrophage autophagy during LPS stimulation. Conclusion We defined a new molecular pathway in which LPS-induced foam cell formation is regulated through autophagy. These findings facilitate the understanding of the role of autophagy in the development of atherosclerosis.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Jing Ye
- Department of Pathology, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China.
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21
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Lu Z, Li Y, Samuvel DJ, Jin J, Zhang X, Lopes-Virella MF, Huang Y. MD-2 is involved in the stimulation of matrix metalloproteinase-1 expression by interferon-γ and high glucose in mononuclear cells - a potential role of MD-2 in Toll-like receptor 4-independent signalling. Immunology 2013; 140:301-13. [PMID: 23800176 DOI: 10.1111/imm.12138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 05/20/2013] [Accepted: 06/20/2013] [Indexed: 11/27/2022] Open
Abstract
We reported recently that treatment of diabetic apolipoprotein E-deficient mice with the Toll-like receptor 4 (TLR4) antagonist Rs-LPS, a lipopolysaccharide isolated from Rhodobacter sphaeroides, inhibited atherosclerosis. Since it is known that Rs-LPS antagonizes TLR4 by targeting TLR4 co-receptor MD-2, this finding indicates that MD-2 is a potential target for the treatment of atherosclerosis. In this study, we determined if MD-2 is involved in the gene expression regulated by signalling pathways independent of TLR4. Given that interferon-γ (IFNγ) and hyperglycaemia play key roles in atherosclerosis, we determined if MD-2 is involved in IFN-γ and high-glucose-regulated gene expression in mononuclear cells. Results showed that IFN-γ and high glucose synergistically stimulated matrix metalloproteinase 1 (MMP-1), a proteinase essential for vascular tissue remodelling and atherosclerosis, in U937 mononuclear cells, but Rs-LPS inhibited the MMP-1 stimulation. To provide more evidence for a role of MD-2 in IFN-γ-stimulated MMP-1, studies using antibodies and small interfering RNA demonstrated that MD-2 blockade or knockdown attenuated the effect of IFN-γ on MMP-1. Furthermore, studies using PCR arrays showed that MD-2 blockade had a similar effect as IFN-γ receptor blockade on the inhibition of IFN-γ-stimulated pro-inflammatory molecules. Although these findings indicate the involvement of MD-2 in IFN-γ signalling, we also observed that MD-2 was up-regulated by IFN-γ and high glucose. We found that MD-2 up-regulation by IFN-γ played an essential role in the synergistic effect of IFN-γ and LPS on MMP-1 expression. Taken together, these findings indicate that MD-2 is involved in IFN-γ signalling and IFN-γ-augmented MMP-1 up-regulation by LPS.
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Affiliation(s)
- Zhongyang Lu
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, College of Medicine, Medical University of South Carolina, Charleston, SC, USA
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22
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Neves AL, Coelho J, Couto L, Leite-Moreira A, Roncon-Albuquerque R. Metabolic endotoxemia: a molecular link between obesity and cardiovascular risk. J Mol Endocrinol 2013; 51:R51-64. [PMID: 23943858 DOI: 10.1530/jme-13-0079] [Citation(s) in RCA: 150] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Obesity is associated with significantly increased cardiovascular (CV) risk and mortality. Several molecular mechanisms underlying this association have been implied, among which the intestinal barrier has gained a growing interest. In experimental models of obesity, significant alterations in the intestinal barrier lead to increased intestinal permeability, favoring translocation of microbiome-derived lipopolysaccharide to the bloodstream. This has been shown to result in a two- to threefold increase in its serum concentrations, a threshold named 'metabolic endotoxemia' (ME). ME may trigger toll-like receptor 4-mediated inflammatory activation, eliciting a chronic low-grade proinflammatory and pro-oxidative stress status, which may result in high CV risk and target-organ damage. In this review, we discuss the potential molecular implications of ME on several CV risk factors, such as obesity, insulin resistance, dyslipidemia, and oxidative stress, as well as its potential impact on the development of CV target-organ disease.
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Affiliation(s)
- Ana Luísa Neves
- Departments of Physiology and Cardiothoracic Surgery General Practice, Faculty of Medicine, University of Porto, Al. Prof. Hernâni Monteiro; 4200-319 Porto, Portugal
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Brüne B, Dehne N, Grossmann N, Jung M, Namgaladze D, Schmid T, von Knethen A, Weigert A. Redox control of inflammation in macrophages. Antioxid Redox Signal 2013; 19:595-637. [PMID: 23311665 PMCID: PMC3718318 DOI: 10.1089/ars.2012.4785] [Citation(s) in RCA: 275] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 12/14/2012] [Accepted: 01/11/2013] [Indexed: 12/13/2022]
Abstract
Macrophages are present throughout the human body, constitute important immune effector cells, and have variable roles in a great number of pathological, but also physiological, settings. It is apparent that macrophages need to adjust their activation profile toward a steadily changing environment that requires altering their phenotype, a process known as macrophage polarization. Formation of reactive oxygen species (ROS), derived from NADPH-oxidases, mitochondria, or NO-producing enzymes, are not necessarily toxic, but rather compose a network signaling system, known as redox regulation. Formation of redox signals in classically versus alternatively activated macrophages, their action and interaction at the level of key targets, and the resulting physiology still are insufficiently understood. We review the identity, source, and biological activities of ROS produced during macrophage activation, and discuss how they shape the key transcriptional responses evoked by hypoxia-inducible transcription factors, nuclear-erythroid 2-p45-related factor 2 (Nrf2), and peroxisome proliferator-activated receptor-γ. We summarize the mechanisms how redox signals add to the process of macrophage polarization and reprogramming, how this is controlled by the interaction of macrophages with their environment, and addresses the outcome of the polarization process in health and disease. Future studies need to tackle the option whether we can use the knowledge of redox biology in macrophages to shape their mediator profile in pathophysiology, to accelerate healing in injured tissue, to fight the invading pathogens, or to eliminate settings of altered self in tumors.
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Affiliation(s)
- Bernhard Brüne
- Faculty of Medicine, Institute of Biochemistry I-Pathobiochemistry, Goethe-University Frankfurt, Frankfurt, Germany.
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24
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Ronda N, Favari E, Borghi MO, Ingegnoli F, Gerosa M, Chighizola C, Zimetti F, Adorni MP, Bernini F, Meroni PL. Impaired serum cholesterol efflux capacity in rheumatoid arthritis and systemic lupus erythematosus. Ann Rheum Dis 2013; 73:609-15. [PMID: 23562986 DOI: 10.1136/annrheumdis-2012-202914] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES The marked cardiovascular risk in autoimmune diseases is only partly explained. The capacity of high-density lipoproteins (HDL) to promote cell cholesterol efflux is a property with a well-known anti-atherogenic significance, but is also involved in functional modulation of endothelial and immune cells. The aim of this work was to evaluate HDL functionality with respect to cell cholesterol efflux in rheumatoid arthritis (RA) and systemic lupus erythemathosus (SLE) patients. METHODS We evaluated serum cholesterol efflux capacity (CEC) of apoB-depleted serum, which mainly reflects HDL activity, from 30 RA and 30 SLE patients, and from 30 healthy controls by radioisotopic ex-vivo systems discriminating between the specific pathways of cholesterol efflux. RESULTS RA patients presented impairment of ATP-binding cassette G1-mediated CEC that correlated with disease activity. SLE patients showed a more complex pattern of modifications unrelated to disease activity, with marked reduction of ATP-binding cassette G1-mediated CEC and impairment of ATP-binding cassette A1-mediated CEC. The relationship between specific pathways of CEC values and serum total HDL differed between groups and there was no relationship with autoantibody profile or current therapy. CONCLUSIONS CEC is impaired in RA and SLE, with a specific mechanism pattern in each disease not depending on serum HDL levels. These findings provide a new mechanism for the increased atherosclerotic risk in RA and SLE patients.
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Kim Y, Kong M, Lee C. Association of intronic sequence variant in the gene encoding spleen tyrosine kinase with susceptibility to vascular dementia. World J Biol Psychiatry 2013; 14:220-6. [PMID: 23480133 DOI: 10.3109/15622975.2011.559272] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES This study was aimed to identify a novel strong candidate gene for the susceptibility to vascular dementia (VaD) with comprehensive evidences. METHODS A preliminary genome-wide association study (GWAS) was conducted to identify nucleotide sequence variants susceptible to VaD. Literature-based analysis and network analysis were conducted to single out the best candidate gene, and its association was thoroughly examined over its whole sequences. Functions of the most probable variant were predicted by in silico alternative splicing analysis and evaluated by minigene assay. RESULTS The GWAS showed the most significant variant in spleen tyrosine kinase (SYK) gene. This concurred with the suggestions from both literature-based analysis and network analysis. Further association analysis over the whole SYK gene revealed that rs290227 in intron 8 was the most significant (P = 7.38 × 10(-11)). The subsequent in silico analysis showed that the intronic variant played potential roles in alternative splicing by skipping exon 8 or by truncating exon 9. It was validated by in vivo minigene assay that the G allele of rs290227 induced the delayed splicing. CONCLUSIONS We suggested a novel association of the VaD susceptibility with an intronic variant of rs290227 in the SYK gene. Its Gallele could render mature transcripts inappropriately by intron retention and thus lead to a genetic risk for VaD.
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Affiliation(s)
- Younyoung Kim
- Department of Bioinformatics and Life Science, Soongsil University, Seoul, Korea
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26
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Miller YI, Choi SH, Wiesner P, Bae YS. The SYK side of TLR4: signalling mechanisms in response to LPS and minimally oxidized LDL. Br J Pharmacol 2013; 167:990-9. [PMID: 22776094 DOI: 10.1111/j.1476-5381.2012.02097.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Spleen tyrosine kinase (SYK) is the best known for its involvement in immune receptor signalling, mediated by binding of SYK tandem Src-homology 2 domains to tandem phosphotyrosine in immunoreceptor tyrosine-based activation motifs (ITAMs). ITAM adaptors or ITAM-containing receptor tails mediate signalling from B- and T-cell receptors, Fc receptors and many C-type lectins, including dectin-1. Recent data point to constitutive binding of SYK to the cytoplasmic domain of toll-like receptor-4 (TLR4). This SYK-TLR4 binding increases upon TLR4 dimerization and phosphorylation, and SYK plays a prominent role in TLR4 signalling in response to LPS in neutrophils and monocytes. SYK also plays an important role in TLR4-mediated macrophage responses to minimally oxidized low-density lipoprotein (mmLDL), which is a form of oxidized LDL relevant to development of human atherosclerosis. Interestingly, mmLDL-induced effects in macrophages, which occur via TLR4, are predominantly MyD88 independent. This unmasks the role of the SYK branch of TLR4 signalling, which mediates modest cytokine release via activation of AP-1 transcription and robust reactive oxygen species generation and cytoskeletal rearrangements. The latter results in extensive membrane ruffling and macropinocytosis, leading to lipoprotein uptake and foam cell formation, a hallmark of atherosclerotic lesions. Because inhibitors of SYK activity, such as fostamatinib, are in advanced clinical trials for rheumatoid arthritis and other autoimmune diseases, understanding the role of SYK in signalling via TLR4 is of immediate importance. This signalling pathway seems to be particularly important in TLR4 activation by host-derived, damage-associated molecular pattern ligands, such as mmLDL, relevant to development of atherosclerosis and other chronic inflammatory diseases.
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Affiliation(s)
- Yury I Miller
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
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27
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Kelly C, Canning P, Buchanan PJ, Williams MT, Brown V, Gruenert DC, Elborn JS, Ennis M, Schock BC. Toll-like receptor 4 is not targeted to the lysosome in cystic fibrosis airway epithelial cells. Am J Physiol Lung Cell Mol Physiol 2013; 304:L371-82. [PMID: 23316065 PMCID: PMC4073939 DOI: 10.1152/ajplung.00372.2011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 01/03/2013] [Indexed: 01/13/2023] Open
Abstract
The innate immune response to bacterial infection is mediated through Toll-like receptors (TLRs), which trigger tightly regulated signaling cascades through transcription factors including NF-κB. LPS activation of TLR4 triggers internalization of the receptor-ligand complex which is directed toward lysosomal degradation or endocytic recycling. Cystic fibrosis (CF) patients display a robust and uncontrolled inflammatory response to bacterial infection, suggesting a defect in regulation. This study examined the intracellular trafficking of TLR4 in CF and non-CF airway epithelial cells following stimulation with LPS. We employed cells lines [16hBE14o-, CFBE41o- (CF), and CFTR-complemented CFBE41o-] and confirmed selected experiments in primary nasal epithelial cells from non-CF controls and CF patients (F508del homozygous). In control cells, TLR4 expression (surface and cytoplasmic) was reduced after LPS stimulation but remained unchanged in CF cells and was accompanied by a heightened inflammatory response 24 h after stimulation. All cells expressed markers of the early (EEA1) and late (Rab7b) endosomes at basal levels. However, only CF cells displayed persistent expression of Rab7b following LPS stimulation. Rab7 variants may directly internalize bacteria to the Golgi for recycling or to the lysosome for degradation. TLR4 colocalized with the lysosomal marker LAMP1 in 16 hBE14o- cells, suggesting that TLR4 is targeted for lysosomal degradation in these cells. However, this colocalization was not observed in CFBE41o- cells, where persistent expression of Rab7 and release of proinflammatory cytokines was detected. Consistent with the apparent inability of CF cells to target TLR4 toward the lysosome for degradation, we observed persistent surface and cytoplasmic expression of this pathogen recognition receptor. This defect may account for the prolonged cycle of chronic inflammation associated with CF.
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Affiliation(s)
- Catriona Kelly
- Centre for Infection and Immunity, Queen's University of Belfast, Belfast, UK
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28
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García RA, Search DJ, Lupisella JA, Ostrowski J, Guan B, Chen J, Yang WP, Truong A, He A, Zhang R, Yan M, Hellings SE, Gargalovic PS, Ryan CS, Watson LM, Langish RA, Shipkova PA, Carson NL, Taylor JR, Yang R, Psaltis GC, Harrity TW, Robl JA, Gordon DA. 11β-hydroxysteroid dehydrogenase type 1 gene knockout attenuates atherosclerosis and in vivo foam cell formation in hyperlipidemic apoE⁻/⁻ mice. PLoS One 2013; 8:e53192. [PMID: 23383297 PMCID: PMC3562192 DOI: 10.1371/journal.pone.0053192] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 11/29/2012] [Indexed: 11/22/2022] Open
Abstract
Background Chronic glucocorticoid excess has been linked to increased atherosclerosis and general cardiovascular risk in humans. The enzyme 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) increases active glucocorticoid levels within tissues by catalyzing the conversion of cortisone to cortisol. Pharmacological inhibition of 11βHSD1 has been shown to reduce atherosclerosis in murine models. However, the cellular and molecular details for this effect have not been elucidated. Methodology/Principal Findings To examine the role of 11βHSD1 in atherogenesis, 11βHSD1 knockout mice were created on the pro-atherogenic apoE−/− background. Following 14 weeks of Western diet, aortic cholesterol levels were reduced 50% in 11βHSD1−/−/apoE−/− mice vs. 11βHSD1+/+/apoE−/− mice without changes in plasma cholesterol. Aortic 7-ketocholesterol content was reduced 40% in 11βHSD1−/−/apoE−/− mice vs. control. In the aortic root, plaque size, necrotic core area and macrophage content were reduced ∼30% in 11βHSD1−/−/apoE−/− mice. Bone marrow transplantation from 11βHSD1−/−/apoE−/− mice into apoE−/− recipients reduced plaque area 39–46% in the thoracic aorta. In vivo foam cell formation was evaluated in thioglycollate-elicited peritoneal macrophages from 11βHSD1+/+/apoE−/− and 11βHSD1−/−/apoE−/− mice fed a Western diet for ∼5 weeks. Foam cell cholesterol levels were reduced 48% in 11βHSD1−/−/apoE−/− mice vs. control. Microarray profiling of peritoneal macrophages revealed differential expression of genes involved in inflammation, stress response and energy metabolism. Several toll-like receptors (TLRs) were downregulated in 11βHSD1−/−/apoE−/− mice including TLR 1, 3 and 4. Cytokine release from 11βHSD1−/−/apoE−/−-derived peritoneal foam cells was attenuated following challenge with oxidized LDL. Conclusions These findings suggest that 11βHSD1 inhibition may have the potential to limit plaque development at the vessel wall and regulate foam cell formation independent of changes in plasma lipids. The diminished cytokine response to oxidized LDL stimulation is consistent with the reduction in TLR expression and suggests involvement of 11βHSD1 in modulating binding of pro-atherogenic TLR ligands.
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Affiliation(s)
- Ricardo A. García
- Cardiovascular Drug Discovery, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Debra J. Search
- Cardiovascular Drug Discovery, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - John A. Lupisella
- Cardiovascular Drug Discovery, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Jacek Ostrowski
- Cardiovascular Drug Discovery, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Bo Guan
- Applied Genomics, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Jian Chen
- Applied Genomics, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Wen-Pin Yang
- Applied Genomics, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Amy Truong
- Applied Genomics, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Aiqing He
- Applied Genomics, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Rongan Zhang
- Cardiovascular Drug Discovery, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Mujing Yan
- Cardiovascular Drug Discovery, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Samuel E. Hellings
- Cardiovascular Drug Discovery, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Peter S. Gargalovic
- Cardiovascular Drug Discovery, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Carol S. Ryan
- Cardiovascular Drug Discovery, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Linda M. Watson
- Pharmaceutical Compound Optimization: Discovery Toxicology, Bristol-Myers Squibb Company, Lawrenceville, New Jersey, United States of America
| | - Robert A. Langish
- Pharmaceutical Compound Optimization: Discovery Analytical Sciences, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Petia A. Shipkova
- Pharmaceutical Compound Optimization: Discovery Analytical Sciences, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Nancy L. Carson
- Cardiovascular Drug Discovery, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Joseph R. Taylor
- Metabolic Diseases, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Richard Yang
- Cardiovascular Drug Discovery, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - George C. Psaltis
- Veterinary Sciences, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Thomas W. Harrity
- Cardiovascular Drug Discovery, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - Jeffrey A. Robl
- Discovery Chemistry, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
| | - David A. Gordon
- Cardiovascular Drug Discovery, Bristol-Myers Squibb Company, Pennington, New Jersey, United States of America
- * E-mail:
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Ruotsalainen AK, Inkala M, Partanen ME, Lappalainen JP, Kansanen E, Mäkinen PI, Heinonen SE, Laitinen HM, Heikkilä J, Vatanen T, Hörkkö S, Yamamoto M, Ylä-Herttuala S, Jauhiainen M, Levonen AL. The absence of macrophage Nrf2 promotes early atherogenesis. Cardiovasc Res 2013; 98:107-15. [PMID: 23341579 DOI: 10.1093/cvr/cvt008] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
AIMS The loss of nuclear factor E2-related factor 2 (Nrf2) has been shown to protect against atherogenesis in apoE-deficient mice. The mechanism by which Nrf2 deficiency affords atheroprotection in this model is currently unknown, but combined systemic and local vascular effects on lesion macrophages have been proposed. We investigated the effect of bone marrow-specific loss of Nrf2 on early atherogenesis in low-density lipoprotein (LDL) receptor-deficient (LDLR(-/-)) mice, and assessed the effect of Nrf2 on cellular accumulation of modified LDLs and the expression of inflammatory markers in macrophages. METHODS AND RESULTS The effect of bone marrow-specific loss of Nrf2 on atherogenesis was studied using bone marrow transplantation of wild-type (WT) or Nrf2(-/-) bone marrow to LDLR(-/-) mice. Mice transplanted with Nrf2(-/-) bone marrow and fed a high-fat diet for 6 weeks exhibited significantly larger atherosclerotic lesions than WT bone marrow transplanted mice. Moreover, in thioglycollate-elicited Nrf2(-/-) macrophages, the uptake of acetylated and malondialdehyde-modified LDLs was increased in comparison with WT controls, with the concomitant increase in the expression of scavenger receptor A and toll-like receptor 4. In addition, the expression of pro-inflammatory monocyte chemoattractant protein-1 and interleukin-6 were increased in Nrf2(-/-) vs. WT macrophages. CONCLUSION Nrf2 deficiency specific to bone marrow-derived cells aggravates atherosclerosis in LDLR(-/-) mice. Furthermore, the loss of Nrf2 in macrophages enhances foam cell formation and promotes the pro-inflammatory phenotype.
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Affiliation(s)
- Anna-Kaisa Ruotsalainen
- Department of Biotechnology and Molecular Medicine, A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland, Neulaniementie 2, Kuopio FIN-70211, Finland
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Karagiannis GS, Weile J, Bader GD, Minta J. Integrative pathway dissection of molecular mechanisms of moxLDL-induced vascular smooth muscle phenotype transformation. BMC Cardiovasc Disord 2013; 13:4. [PMID: 23324130 PMCID: PMC3556327 DOI: 10.1186/1471-2261-13-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 12/29/2012] [Indexed: 01/08/2023] Open
Abstract
Background Atherosclerosis (AT) is a chronic inflammatory disease characterized by the accumulation of inflammatory cells, lipoproteins and fibrous tissue in the walls of arteries. AT is the primary cause of heart attacks and stroke and is the leading cause of death in Western countries. To date, the pathogenesis of AT is not well-defined. Studies have shown that the dedifferentiation of contractile and quiescent vascular smooth muscle cells (SMC) to the proliferative, migratory and synthetic phenotype in the intima is pivotal for the onset and progression of AT. To further delineate the mechanisms underlying the pathogenesis of AT, we analyzed the early molecular pathways and networks involved in the SMC phenotype transformation. Methods Quiescent human coronary artery SMCs were treated with minimally-oxidized LDL (moxLDL), for 3 hours and 21 hours, respectively. Transcriptomic data was generated for both time-points using microarrays and was subjected to pathway analysis using Gene Set Enrichment Analysis, GeneMANIA and Ingenuity software tools. Gene expression heat maps and pathways enriched in differentially expressed genes were compared to identify functional biological themes to elucidate early and late molecular mechanisms of moxLDL-induced SMC dedifferentiation. Results Differentially expressed genes were found to be enriched in cholesterol biosynthesis, inflammatory cytokines, chemokines, growth factors, cell cycle control and myogenic contraction themes. These pathways are consistent with inflammatory responses, cell proliferation, migration and ECM production, which are characteristic of SMC dedifferentiation. Furthermore, up-regulation of cholesterol synthesis and dysregulation of cholesterol metabolism was observed in moxLDL-induced SMC. These observations are consistent with the accumulation of cholesterol and oxidized cholesterol esters, which induce proinflammatory reactions during atherogenesis. Our data implicate for the first time IL12, IFN-α, HGF, CSF3, and VEGF signaling in SMC phenotype transformation. GPCR signaling, HBP1 (repressor of cyclin D1 and CDKN1B), and ID2 and ZEB1 transcriptional regulators were also found to have important roles in SMC dedifferentiation. Several microRNAs were observed to regulate the SMC phenotype transformation via an interaction with IFN-γ pathway. Also, several “nexus” genes in complex networks, including components of the multi-subunit enzyme complex involved in the terminal stages of cholesterol synthesis, microRNAs (miR-203, miR-511, miR-590-3p, miR-346*/miR- 1207-5p/miR-4763-3p), GPCR proteins (GPR1, GPR64, GPRC5A, GPR171, GPR176, GPR32, GPR25, GPR124) and signal transduction pathways, were found to be regulated. Conclusions The systems biology analysis of the in vitro model of moxLDL-induced VSMC phenotype transformation was associated with the regulation of several genes not previously implicated in SMC phenotype transformation. The identification of these potential candidate genes enable hypothesis generation and in vivo functional experimentation (such as gain and loss-of-function studies) to establish causality with the process of SMC phenotype transformation and atherogenesis.
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Affiliation(s)
- George S Karagiannis
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, and Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, M5S 1A8, Canada
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31
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Nazari-Jahantigh M, Wei Y, Noels H, Akhtar S, Zhou Z, Koenen RR, Heyll K, Gremse F, Kiessling F, Grommes J, Weber C, Schober A. MicroRNA-155 promotes atherosclerosis by repressing Bcl6 in macrophages. J Clin Invest 2012; 122:4190-202. [PMID: 23041630 DOI: 10.1172/jci61716] [Citation(s) in RCA: 406] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 08/20/2012] [Indexed: 12/14/2022] Open
Abstract
Macrophages in atherosclerotic plaques drive inflammatory responses, degrade lipoproteins, and phagocytose dead cells. MicroRNAs (miRs) control the differentiation and activity of macrophages by regulating the signaling of key transcription factors. However, the functional role of macrophage-related miRs in the immune response during atherogenesis is unknown. Here, we report that miR-155 is specifically expressed in atherosclerotic plaques and proinflammatory macrophages, where it was induced by treatment with mildly oxidized LDL (moxLDL) and IFN-γ. Leukocyte-specific Mir155 deficiency reduced plaque size and number of lesional macrophages after partial carotid ligation in atherosclerotic (Apoe-/-) mice. In macrophages stimulated with moxLDL/IFN-γ in vitro, and in lesional macrophages, loss of Mir155 reduced the expression of the chemokine CCL2, which promotes the recruitment of monocytes to atherosclerotic plaques. Additionally, we found that miR-155 directly repressed expression of BCL6, a transcription factor that attenuates proinflammatory NF-κB signaling. Silencing of Bcl6 in mice harboring Mir155-/- macrophages enhanced plaque formation and CCL2 expression. Taken together, these data demonstrated that miR-155 plays a key role in atherogenic programming of macrophages to sustain and enhance vascular inflammation.
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32
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Fang L, Miller YI. Emerging applications for zebrafish as a model organism to study oxidative mechanisms and their roles in inflammation and vascular accumulation of oxidized lipids. Free Radic Biol Med 2012; 53:1411-20. [PMID: 22906686 PMCID: PMC3448821 DOI: 10.1016/j.freeradbiomed.2012.08.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 07/16/2012] [Accepted: 08/02/2012] [Indexed: 10/28/2022]
Abstract
With the advent of genetic engineering, zebrafish (Danio rerio) were recognized as an attractive model organism to study many biological processes. Remarkably, the small size and optical transparency of zebrafish larvae enable high-resolution imaging of live animals. Zebrafish respond to various environmental and pathological factors with robust oxidative stress. In this article, we provide an overview of the molecular mechanisms involved in oxidative stress and antioxidant response in zebrafish. Existing applications of genetically encoded fluorescent sensors allow imaging, in real time, of the production of H(2)O(2) and studying its involvement in inflammatory responses, as well as activation of the oxidation-sensitive transcription factors HIF and NRF2. Oxidative stress, combined with hyperlipidemia, leads to oxidation of lipoproteins, the process that contributes significantly to the development of atherosclerosis in humans. Recent work found that feeding zebrafish a high-cholesterol diet results in hypercholesterolemia, vascular lipid accumulation, and extreme lipoprotein oxidation. Generation of a transgenic zebrafish expressing a green fluorescent protein-tagged human antibody to malondialdehyde (MDA)-modified LDL makes possible the in vivo visualization of MDA epitopes in the vascular wall and testing of the efficacy of antioxidants and dietary interventions. Thus, using zebrafish as a model organism provides important advantages in studying the roles of reactive oxygen species and lipid oxidation in basic biologic and pathologic processes.
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Affiliation(s)
- Longhou Fang
- Department of Medicine, University of California at San Diego, La Jolla, CA 92093, USA.
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33
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Radhika A, Sudhakaran PR. Upregulation of macrophage-specific functions by oxidized LDL: lysosomal degradation-dependent and -independent pathways. Mol Cell Biochem 2012; 372:181-90. [PMID: 23054190 DOI: 10.1007/s11010-012-1459-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 09/14/2012] [Indexed: 02/02/2023]
Abstract
Formation of foam cells from macrophages, which are formed by the differentiation of blood-borne monocytes, is a critical early event in atherogenesis. To examine how pre-exposure of monocytes to modified proteins, such as oxLDL, influences their differentiation to macrophages, an in vitro model system using isolated PBMC maintained in culture in the presence of oxLDL was used. Pretreatment of monocytes with oxLDL caused a faster rate of expression of macrophage-specific functions and loss of monocyte-specific functions compared to unmodified LDL. The effect of oxidation of lipid component of LDL by CuSO(4) and its protein component by HOCl, on mo-mϕ differentiation was studied by monitoring the upregulation of macrophage-specific functions, particularly MMP-9. Chloroquine, a lysosomal degradation blocker, significantly reversed the effect mediated by CuSO(4) oxLDL, indicating the involvement of lysosomal degradation products, while no such effect was observed in HOCl oxLDL-treated cells, indicating the existence of a pathway independent of its lysosomal degradation products. Reversal of the effect of oxLDL by NAC and Calphostin C, an inhibitor of PKC, suggested the activation of RO-mediated signaling pathways. Use of inhibitors of signaling pathways showed that CuSO(4) oxLDL upregulated mϕ-specific MMP-9 through p38 MAPK and Akt-dependent pathways, while HOCl oxLDL utilized ERK ½ and Akt. Further analysis showed the activation of PPARγ and AP-1 in CuSO(4) oxLDL, while HOCl-oxLDL-mediated effect involved NFκB and AP-1. These results suggest that lipid oxLDL- and protein oxLDL-mediated upregulation of mo-mϕ-specific functions involve lysosomal degradation-dependent and -independent activation of intracellular signaling pathways.
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Affiliation(s)
- A Radhika
- Department of Biochemistry, University of Kerala, Kariavattom, Trivandrum 695 581, India
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34
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Laguna JC, Alegret M. Regulation of gene expression in atherosclerosis: insights from microarray studies in monocytes/macrophages. Pharmacogenomics 2012; 13:477-95. [PMID: 22380002 DOI: 10.2217/pgs.12.9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Atherosclerosis is a pathological phenomenon in which the walls of large arteries thicken and lose elasticity as a result of the growth of atheromatous lesions. It is a complex, multifactorial disease that involves several cell types and various pathobiological processes. Its genetic basis has not yet been deciphered, but it is related to complex multigene patterns influenced by environmental interactions. In this review, we focus specifically on the application of microarrays to atherosclerosis research using monocytes and monocyte-derived macrophages, as these are key cells in all phases of atherosclerosis, from the formation of foam cells to the destabilization and rupture of the atherosclerotic plaque. These studies have provided relevant information on genes involved in atherosclerosis development, contributing to our understanding of the molecular mechanisms that underlie this complex disease.
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Affiliation(s)
- Juan C Laguna
- Pharmacology Department, Faculty of Pharmacy & Institute of Biomedicine (IBUB), University of Barcelona, Spain
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35
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Crittenden DB, Lehmann RA, Schneck L, Keenan RT, Shah B, Greenberg JD, Cronstein BN, Sedlis SP, Pillinger MH. Colchicine use is associated with decreased prevalence of myocardial infarction in patients with gout. J Rheumatol 2012; 39:1458-64. [PMID: 22660810 DOI: 10.3899/jrheum.111533] [Citation(s) in RCA: 132] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE The ability of antiinflammatory strategies to alter cardiovascular risk has not been rigorously examined. Colchicine is an antiinflammatory agent that affects macrophages, neutrophils, and endothelial cells, all of which are implicated in the pathogenesis of cardiovascular disease. We examined whether colchicine use was associated with a reduced risk of myocardial infarction (MI) in patients with gout. METHODS We conducted a retrospective, cross-sectional study of all patients with an International Classification of Diseases, 9th ed, code for gout in the electronic medical record (EMR) of the New York Harbor Healthcare System Veterans Affairs network and ≥ 1 hospital visit between August 2007 and August 2008. Hospital pharmacy data were used to identify patients who had filled at least 1 colchicine prescription versus those who had not. Demographics and CV comorbidities were collected by EMR review. The primary outcome was diagnosis of MI. Secondary outcomes included all-cause mortality and C-reactive protein (CRP) level. RESULTS In total, 1288 gout patients were identified. Colchicine (n = 576) and no colchicine (n = 712) groups had similar baseline demographics and serum urate levels. Prevalence of MI was 1.2% in the colchicine versus 2.6% in the no-colchicine group (p = 0.03). Colchicine users also had fewer deaths and lower CRP levels, although these did not achieve statistical significance. Colchicine effects persisted when allopurinol users were excluded from the analysis. CONCLUSION In this hypothesis-generating study, gout patients who took colchicine had a significantly lower prevalence of MI and exhibited trends toward reduced all-cause mortality and lower CRP level versus those who did not take colchicine.
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Affiliation(s)
- Daria B Crittenden
- Crystal Diseases Study Group, Division of Rheumatology, New York University School of Medicine, New York, New York 10003, USA.
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Minimally modified low-density lipoprotein induces macrophage endoplasmic reticulum stress via toll-like receptor 4. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:954-63. [PMID: 22480542 DOI: 10.1016/j.bbalip.2012.03.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 03/06/2012] [Accepted: 03/12/2012] [Indexed: 01/21/2023]
Abstract
Minimally modified low-density lipoprotein (mm-LDL) induces intimal foam cell formation, which is promoted by endoplasmic reticulum stress (ERS), a cross-point to link cellular processes with multiple risk factors that exist in all stages of atherosclerosis. However, it remains unclear whether mm-LDL-induced lipid accumulation in macrophages involves ERS and its underlying mechanisms. We showed that mm-LDL induced the accumulation of lipid droplets in RAW264.7 macrophages with increased free cholesterol in the endoplasmic reticulum, which was markedly attenuated by pretreatment with an antibody against toll-like receptor 4 (TLR4). Additionally, mm-LDL stimulated the transport of Cy3-labeled activating transcription factor 6 (ATF6), a key sensor to the unfolded protein response (UPR), from cytoplasm into nucleus. The expression of phosphorylated inositol-requiring enzyme 1 (p-IRE1), another sensor to the UPR, and its two downstream molecules, X box binding protein 1 and glucose-regulated protein 78 (GRP78), were significantly upregulated by mm-LDL. The alterations induced by mm-LDL were all significantly inhibited by antibodies against TLR4 or CD36. In addition, the upregulation of p-IRE1 and GRP78 and the nuclear translocation of ATF6 induced by mm-LDL were significantly attenuated by TLR4 siRNA. These results suggest that mm-LDL may induce free cholesterol accumulation in the endoplasmic reticulum and subsequently stimulate ERS and activate the UPR signaling pathway mediated by ATF6 and IRE1 in macrophages, a process that is potentially mediated by TLR4.
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Choi SH, Wiesner P, Almazan F, Kim J, Miller YI. Spleen tyrosine kinase regulates AP-1 dependent transcriptional response to minimally oxidized LDL. PLoS One 2012; 7:e32378. [PMID: 22384232 PMCID: PMC3284564 DOI: 10.1371/journal.pone.0032378] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 01/28/2012] [Indexed: 12/16/2022] Open
Abstract
Oxidative modification of low-density lipoprotein (LDL) turns it into an endogenous ligand recognized by pattern-recognition receptors. We have demonstrated that minimally oxidized LDL (mmLDL) binds to CD14 and mediates TLR4/MD-2-dependent responses in macrophages, many of which are MyD88-independent. We have also demonstrated that the mmLDL activation leads to recruitment of spleen tyrosine kinase (Syk) to TLR4 and TLR4 and Syk phosphorylation. In this study, we produced a macrophage-specific Syk knockout mouse and used primary Syk(-/-) macrophages in our studies. We demonstrated that Syk mediated phosphorylation of ERK1/2 and JNK, which in turn phosphorylated c-Fos and c-Jun, respectively, as assessed by an in vitro kinase assay. c-Jun phosphorylation was also mediated by IKKε. c-Jun and c-Fos bound to consensus DNA sites and thereby completed an AP-1 transcriptional complex and induced expression of CXCL2 and IL-6. These results suggest that Syk plays a key role in TLR4-mediated macrophage responses to host-generated ligands, like mmLDL, with subsequent activation of an AP-1 transcription program.
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Affiliation(s)
| | | | | | | | - Yury I. Miller
- Department of Medicine, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
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Leonarduzzi G, Gamba P, Gargiulo S, Biasi F, Poli G. Inflammation-related gene expression by lipid oxidation-derived products in the progression of atherosclerosis. Free Radic Biol Med 2012; 52:19-34. [PMID: 22037514 DOI: 10.1016/j.freeradbiomed.2011.09.031] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 09/16/2011] [Accepted: 09/24/2011] [Indexed: 12/31/2022]
Abstract
Vascular areas of atherosclerotic development persist in a state of inflammation, and any further inflammatory stimulus in the subintimal area elicits a proatherogenic response; this alters the behavior of the artery wall cells and recruits further inflammatory cells. In association with the inflammatory response, oxidative events are also involved in the development of atherosclerotic plaques. It is now unanimously recognized that lipid oxidation-derived products are key players in the initiation and progression of atherosclerotic lesions. Oxidized lipids, derived from oxidatively modified low-density lipoproteins (LDLs), which accumulate in the intima, strongly modulate inflammation-related gene expression, through involvement of various signaling pathways. In addition, considerable evidence supports a proatherogenic role of a large group of potent bioactive lipids called eicosanoids, which derive from oxidation of arachidonic acid, a component of membrane phospholipids. Of note, LDL lipid oxidation products might regulate eicosanoid production, modulating the enzymatic degradation of arachidonic acid by cyclooxygenases and lipoxygenases; these enzymes might also directly contribute to LDL oxidation. This review provides a comprehensive overview of current knowledge on signal transduction pathways and inflammatory gene expression, modulated by lipid oxidation-derived products, in the progression of atherosclerosis.
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Yu M, Kang X, Xue H, Yin H. Toll-like receptor 4 is up-regulated by mTOR activation during THP-1 macrophage foam cells formation. Acta Biochim Biophys Sin (Shanghai) 2011; 43:940-7. [PMID: 22015781 DOI: 10.1093/abbs/gmr093] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Macrophage foam cells formation is the most important process in atherosclerotic plaque formation and development. Toll-like receptor 4 (TLR4) is one of the important innate immune sensors of endogenous damage signals and crucial for regulating inflammation. Growing evidence indicates that TLR4 plays a very important role in macrophage foam cells formation. However, the underlying mechanisms regulating TLR4 expression in macrophage are not fully understood. In this study, we induced THP-1 macrophage foam cells formation with oxidative modified low-density lipoprotein (ox-LDL). We observed that TLR4 mRNA and protein expression were markedly up-regulated, and the phosphorylation of mammalian target of rapamycin (mTOR) and its downstream target p70S6K were promoted during foam cells formation. The mTOR inhibitor rapamycin blocked mTOR phosphorylation and inhibited TLR4 expression induced by ox-LDL. Silencing mTOR, rictor or raptor protein expression by small interfering RNA, also inhibited the up-regulation of TLR4 expression, respectively. Inhibition of mTOR with rapamycin reversed the down-regulation of cellular lipid efflux mediator ABCA1, which resulted from the activation of TLR4 by ligands. These data suggested that TRL4 expression was up-regulated by a mechanism dependent on mTOR signal pathway activation during THP-1 macrophage foam cells formation. Inhibition of ox-LDL induced mTOR activation reduced TLR4 expression, and improved the impaired lipid efflux.
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Affiliation(s)
- Miao Yu
- Key laboratory of Endocrinology, Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
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Kruth HS. Receptor-independent fluid-phase pinocytosis mechanisms for induction of foam cell formation with native low-density lipoprotein particles. Curr Opin Lipidol 2011; 22:386-93. [PMID: 21881499 PMCID: PMC4174540 DOI: 10.1097/mol.0b013e32834adadb] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
PURPOSE OF REVIEW Because early findings indicated that native low-density lipoprotein (LDL) did not substantially increase macrophage cholesterol content during in-vitro incubations, investigators presumed that LDL must be modified in some way to trigger its uptake by the macrophage. The purpose of this review is to discuss recent findings showing that native unmodified LDL can induce massive macrophage cholesterol accumulation mimicking macrophage foam cell formation that occurs within atherosclerotic plaques. RECENT FINDINGS Macrophages that show high rates of fluid-phase pinocytosis also show similar high rates of uptake of native unmodified LDL through nonreceptor mediated uptake within both macropinosomes and micropinosomes. Nonsaturable fluid-phase uptake of LDL by macrophages converts the macrophages into foam cells. Different macrophage phenotypes demonstrate either constitutive fluid-phase pinocytosis or inducible fluid-phase pinocytosis. Fluid-phase pinocytosis has been demonstrated by macrophages within mouse atherosclerotic plaques indicating that this pathway contributes to plaque macrophage cholesterol accumulation. SUMMARY Contrary to what has been believed previously, macrophages can take up large amounts of native unmodified LDL by receptor-independent, fluid-phase pinocytosis converting these macrophages into foam cells. Thus, targeting macrophage fluid-phase pinocytosis should be considered when investigating strategies to limit macrophage cholesterol accumulation in atherosclerotic plaques.
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Affiliation(s)
- Howard S Kruth
- Section of Experimental Atherosclerosis, National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland 20892-1422, USA.
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41
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Zhao L, Lee JY, Hwang DH. Inhibition of pattern recognition receptor-mediated inflammation by bioactive phytochemicals. Nutr Rev 2011; 69:310-20. [PMID: 21631512 DOI: 10.1111/j.1753-4887.2011.00394.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Emerging evidence reveals that pattern-recognition receptors (PRRs), Toll-like receptors (TLRs), and nucleotide-binding oligomerization domain proteins (NODs) mediate both infection-induced and sterile inflammation by recognizing pathogen-associated molecular patterns and endogenous molecules, respectively. PRR-mediated chronic inflammation is a determinant for the development and progression of chronic diseases including cancer, atherosclerosis, and insulin resistance. Recent studies demonstrated that certain phytochemicals inhibit PRR-mediated pro-inflammation. Curcumin, helenalin, and cinnamaldehyde with α, β-unsaturated carbonyl groups, or sulforaphane with an isothiocyanate group, inhibit TLR4 activation by interfering with cysteine residue-mediated receptor dimerization, while resveratrol, with no unsaturated carbonyl group, did not. Similarly, curcumin, parthenolide, and helenalin, but not resveratrol and (-)-epigallocatechin-3-gallate (EGCG), also inhibit NOD2 activation by interfering with NOD2 dimerization. In contrast, resveratrol, EGCG, luteolin, and structural analogs of luteolin specifically inhibit TLR3 and TLR4 signaling by targeting TANK binding kinase 1 (TBK1) and receptor interacting protein 1 (RIP1) in Toll/IL-1 receptor domain-containing adaptor inducing IFN-β (TRIF) complex. Together, these results suggest that PRRs and downstream signaling components are molecular targets for dietary strategies to reduce PRR-mediated chronic inflammation and consequent risks of chronic diseases.
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Affiliation(s)
- Ling Zhao
- Department of Nutrition, The University of Tennessee, Knoxville, Tennessee, USA
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42
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Orsó E, Grandl M, Schmitz G. Oxidized LDL-induced endolysosomal phospholipidosis and enzymatically modified LDL-induced foam cell formation determine specific lipid species modulation in human macrophages. Chem Phys Lipids 2011; 164:479-87. [DOI: 10.1016/j.chemphyslip.2011.06.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 05/31/2011] [Accepted: 06/01/2011] [Indexed: 01/01/2023]
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Aspartame-fed zebrafish exhibit acute deaths with swimming defects and saccharin-fed zebrafish have elevation of cholesteryl ester transfer protein activity in hypercholesterolemia. Food Chem Toxicol 2011; 49:2899-905. [PMID: 21855599 DOI: 10.1016/j.fct.2011.08.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 08/02/2011] [Accepted: 08/03/2011] [Indexed: 11/20/2022]
Abstract
Although many artificial sweeteners (AS) have safety issues, the AS have been widely used in industry. To determine the physiologic effect of AS in the presence of hyperlipidemia, zebrafish were fed aspartame or saccharin with a high-cholesterol diet (HCD). After 12 days, 30% of zebrafish, which consumed aspartame and HCD, died with exhibiting swimming defects. The aspartame group had 65% survivability, while the control and saccharin groups had 100% survivability. Under HCD, the saccharin-fed groups had the highest increase in the serum cholesterol level (599 mg/dL). Aspartame-fed group showed a remarkable increase in serum glucose (up to 125 mg/dL), which was 58% greater than the increase in the HCD alone group. The saccharin and HCD groups had the highest cholesteryl ester transfer protein (CETP) activity (52% CE-transfer), while the HCD alone group had 42% CE-transfer. Histologic analysis revealed that the aspartame and HCD groups showed more infiltration of inflammatory cells in the brain and liver sections. Conclusively, under presence of hyperlipidemia, aspartame-fed zebrafish exhibited acute swimming defects with an increase in brain inflammation. Saccharin-fed zebrafish had an increased atherogenic serum lipid profile with elevation of CETP activity.
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Howell KW, Meng X, Fullerton DA, Jin C, Reece TB, Cleveland JC. Toll-like receptor 4 mediates oxidized LDL-induced macrophage differentiation to foam cells. J Surg Res 2011; 171:e27-31. [PMID: 21920554 DOI: 10.1016/j.jss.2011.06.033] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 06/03/2011] [Accepted: 06/15/2011] [Indexed: 11/19/2022]
Abstract
BACKGROUND Macrophage foam cells are central in the development of atherosclerosis, but the mechanism of foam cell formation is unclear. Toll-like receptor 4 (TLR4) signaling is known to participate in the pathogenesis of atherosclerosis. Further, oxidized low density lipoprotein (oxLDL) enhances TLR4 expression in macrophages. We hypothesized that TLR4 mediates macrophage differentiation to foam cells. METHODS Peritoneal macrophages were isolated by lavage from TLR4 competent C3H/HeN mice and TLR4 defective C3H/HeJ mice. Cells were treated with oxLDL, lipopolysaccharide (LPS), or oxLDL plus LPS. Cells were also treated with a TLR4 blocking antibody before oxLDL treatment. Foam cells were identified by Oil red O staining for intracellular lipids. Percent macrophage differentiation into foam cells were compared between C3H/HeN and C3H/HeJ macrophages. RESULTS Following oxLDL treatment 29% of TLR4 competent macrophages differentiated into foam cells compared to 5.8% of TLR4 defective macrophages (P < 0.01). Pretreatment with a TLR4 blocking antibody decreased the differentiation of TLR4 competent cells to foam cells from 29% to 13% (P < 0.01). Stimulation of TLR4 with LPS in the presence of oxLDL increased differentiation of TLR4 competent cells to foam cells from 29% to 60% (P < 0.01). In addition, there was a pattern in the spatial relationship between foam cells that were consistently observed in clusters rather than as isolated cells. CONCLUSIONS TLR4 is necessary for oxLDL-induced macrophage differentiation to foam cells. Macrophage foam cell clustering may indicate an underlying intercellular signaling mechanism that facilitates foam cell formation. We conclude that TLR4 contributes to the pathogenesis of atherosclerosis by promoting foam cell formation.
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Affiliation(s)
- Kenneth W Howell
- Department of Surgery, Division of Cardiothoracic Surgery, University of Colorado Anschutz Medical Center, Aurora, Colorado 80045, USA
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45
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Abstract
Vascular inflammation is associated with and in large part driven by changes in the leukocyte compartment of the vessel wall. Here, we focus on monocyte influx during atherosclerosis, the most common form of vascular inflammation. Although the arterial wall contains a large number of resident macrophages and some resident dendritic cells, atherosclerosis drives a rapid influx of inflammatory monocytes (Ly-6C(+) in mice) and other monocytes (Ly-6C(-) in mice, also known as patrolling monocytes). Once in the vessel wall, Ly-6C(+) monocytes differentiate to a phenotype consistent with inflammatory macrophages and inflammatory dendritic cells. The phenotype of these cells is modulated by lipid uptake, Toll-like receptor ligands, hematopoietic growth factors, cytokines, and chemokines. In addition to newly recruited macrophages, it is likely that resident macrophages also change their phenotype. Monocyte-derived inflammatory macrophages have a short half-life. After undergoing apoptosis, they may be taken up by surrounding macrophages or, if the phagocytic capacity is overwhelmed, can undergo secondary necrosis, a key event in forming the necrotic core of atherosclerotic lesions. In this review, we discuss these and other processes associated with monocytic cell dynamics in the vascular wall and their role in the initiation and progression of atherosclerosis.
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Affiliation(s)
- Klaus Ley
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA.
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Wu Y, Tang K, Huang RQ, Zhuang Z, Cheng HL, Yin HX, Shi JX. Therapeutic potential of peroxisome proliferator-activated receptor gamma agonist rosiglitazone in cerebral vasospasm after a rat experimental subarachnoid hemorrhage model. J Neurol Sci 2011; 305:85-91. [DOI: 10.1016/j.jns.2011.03.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2010] [Revised: 02/18/2011] [Accepted: 03/01/2011] [Indexed: 10/18/2022]
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Badimon L, Storey RF, Vilahur G. Update on lipids, inflammation and atherothrombosis. Thromb Haemost 2011; 105 Suppl 1:S34-42. [PMID: 21479344 DOI: 10.1160/ths10-11-0717] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 01/03/2011] [Indexed: 12/21/2022]
Abstract
Atherosclerosis is an inflammatory disease that involves the arterial wall and is characterised by the progressive accumulation of lipids in the vessel wall. The first step is the internalisation of lipids (LDL) in the intima with endothelial activation which enhances the permeability of the endothelial layer and the expression of cytokines/chemokines and adhesion molecules. These events increase LDL particles accumulation in the extracellular matrix where they aggregate/fuse, are retained by proteoglycans and become targets for oxidative and enzymatic modifications. In turn, retained pro-atherogenic LDLs enhance selective leukocyte recruitment and attachment to the endothelial layer inducing their transmigration across the endothelium into the intima. While smooth muscle cell numbers decline with the severity of plaque progression, monocytes differentiate into macrophages, a process associated with the upregulation of pattern recognition receptors including scavenger receptors and Toll-like receptors leading to foam cell formation. Foam cells release growth factors, cytokines, metalloproteinases and reactive oxygen species all of which perpetuate and amplify the vascular remodelling process. In addition, macrophages release tissue factor that, upon plaque rupture, contributes to thrombus formation. Smooth muscle cells exposed in eroded lesions are also able to internalise LDL through LRP-1 receptors acquiring a pro-thrombotic phenotype and releasing tissue factor. Platelets recognise ligands in the ruptured or eroded atherosclerotic plaque, initiate platelet activation and aggregation leading to thrombosis and to the clinical manifestation of the atherothrombotic disease. Additionally, platelets contribute to the local inflammatory response and may also participate in progenitor cell recruitment.
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Affiliation(s)
- Lina Badimon
- Cardiovascular Research Center, c/Sant Antoni Ma. Claret 167, Barcelona, Spain.
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Megens RTA, Kemmerich K, Pyta J, Weber C, Soehnlein O. Intravital imaging of phagocyte recruitment. Thromb Haemost 2011; 105:802-10. [PMID: 21437362 DOI: 10.1160/th10-11-0735] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Accepted: 03/02/2011] [Indexed: 12/28/2022]
Abstract
Extravasation of neutrophils and monocytes is a hallmark event in acute and chronic inflammation. Owing to recent improvements in optical imaging techniques, the classical leukocyte extravasation cascade has been refined with intermediate steps being added. Further studies have shown tissue specific leukocyte recruitment patterns, thus allowing for more selective targeting. Here we focus on recent advances in intravital imaging of leukocyte recruitment by means of optical imaging techniques and emphasise the translation thereof into tissue-specific recruitment to the lungs, the liver and large arteries.
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Affiliation(s)
- R T A Megens
- Institute for Cardiovascular Prevention, Ludwig-Maximilians-University Munich, Munich, Germany.
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49
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Abstract
Cholesterol-engorged macrophage foam cells are a critical component of the atherosclerotic lesion. Reducing the sterol deposits in lesions reduces clinical events. Sterol accumulations within lysosomes have proven to be particularly hard to mobilize out of foam cells. Moreover, excess sterol accumulation in lysosomes has untoward effects, including a complete disruption of lysosome function. Recently, we demonstrated that treatment of sterol-engorged macrophages in culture with triglyceride-containing particles can reverse many of the effects of cholesterol on lysosomes and dramatically reduce the sterol burden in these cells. This article describes what is known about lysosomal sterol engorgement, discusses the possible mechanisms by which triglyceride could produce its effects, and evaluates the possible positive and negative effects of reducing the lysosomal cholesterol levels in foam cells.
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Affiliation(s)
- W Gray Jerome
- Department of Pathology, U-2206 Medical Center North Vanderbilt University School of Medicine 1161 21st Avenue, South Nashville, TN 37232-32561, USA, Tel.: +1 615 322 5530
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50
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Abstract
Chronic inflammation is a key feature of insulin resistance and obesity. Toll-Like Receptor 4 (TLR4), involved in modulating innate immunity, is an important mediator of insulin resistance and its comorbidities. TLR4 contributes to the development of insulin resistance and inflammation through its activation by elevated exogenous ligands (e.g., dietary fatty acids and enteric lipopolysaccharide) and endogenous ligands (e.g., free fatty acids) which are elevated in obese states. TLR4, expressed in insulin target tissues, activates proinflammatory kinases JNK, IKK, and p38 that impair insulin signal transduction directly through inhibitory phosphorylation of insulin receptor substrate (IRS) on serine residues. TLR4 activation also leads to increased transcription of pro-inflammatory genes, resulting in elevation of cytokine, chemokine, reactive oxygen species, and eicosanoid levels that promote further insulin-desensitization within the target cell itself and in other cells via paracrine and systemic effects. Increased understanding of cell type-specific TLR4-mediated effects on insulin action present the opportunity and challenge of developing related therapeutic approaches for improving insulin sensitivity while preserving innate immunity.
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