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Sadeghi S, Nimtz L, Niebergall-Roth E, Norrick A, Hägele S, Vollmer L, Esterlechner J, Frank MH, Ganss C, Scharffetter-Kochanek K, Kluth MA. Potency assay to predict the anti-inflammatory capacity of a cell therapy product for macrophage-driven diseases: overcoming the challenges of assay development and validation. Cytotherapy 2024; 26:512-523. [PMID: 38441512 PMCID: PMC11065629 DOI: 10.1016/j.jcyt.2024.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 01/22/2024] [Accepted: 02/12/2024] [Indexed: 04/04/2024]
Abstract
BACKGROUND Given the high level of product complexity and limited regulatory guidance, designing and implementing appropriate potency assays is often the most challenging part of establishing a quality control testing matrix for a cell-based medicinal product. Among the most elusive tasks are the selection of suitable read-out parameters, the development of assay designs that most closely model the pathophysiological conditions, and the validation of the methods. Here we describe these challenges and how they were addressed in developing an assay that measures the anti-inflammatory potency of mesenchymal stromal cells (MSCs) in an M1 macrophage-dominated inflammatory environment. METHODS An in vitro inflammation model was established by coculturing skin-derived ABCB5+ MSCs with THP-1 monocyte-derived M1-polarized macrophages. Readout was the amount of interleukin 1 receptor antagonist (IL-1RA) secreted by the MSCs in the coculture, measured by an enzyme-linked immunosorbent assay. RESULTS IL-1RA was quantified with guideline-concordant selectivity, accuracy and precision over a relevant concentration range. Consistent induction of the macrophage markers CD36 and CD80 indicated successful macrophage differentiation and M1 polarization of THP-1 cells, which was functionally confirmed by release of proinflammatory tumor necrosis factor α. Testing a wide range of MSC/macrophage ratios revealed the optimal ratio for near-maximal stimulation of MSCs to secrete IL-1RA, providing absolute maximum levels per individual MSC that can be used for future comparison with clinical efficacy. Batch release testing of 71 consecutively manufactured MSC batches showed a low overall failure rate and a high comparability between donors. CONCLUSIONS We describe the systematic development and validation of a therapeutically relevant, straightforward, robust and reproducible potency assay to measure the immunomodulatory capacity of MSCs in M1 macrophage-driven inflammation. The insights into the challenges and how they were addressed may also be helpful to developers of potency assays related to other cellular functions and clinical indications.
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Affiliation(s)
| | | | | | | | | | | | | | - Markus H Frank
- Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts, USA; Transplant Research Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA; School of Medical and Health Sciences, Edith Cowan University, Perth, Western Australia, Australia
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He Y, Liu T. Oxidized low-density lipoprotein regulates macrophage polarization in atherosclerosis. Int Immunopharmacol 2023; 120:110338. [PMID: 37210916 DOI: 10.1016/j.intimp.2023.110338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/10/2023] [Accepted: 05/11/2023] [Indexed: 05/23/2023]
Abstract
Atherosclerosis is the pathological basis of acute cardiovascular and cerebrovascular diseases. Oxidized LDL has been recognized as a major atherogenic factor in the vessel wall for decades. A growing body of evidence suggests that oxidized LDL modulates macrophage phenotypes in atherosclerosis. This article reviews the research progress on the regulation of macrophage polarization by oxidized LDL. Mechanistically, oxidized LDL induces macrophage polarization via cell signaling, metabolic reprogramming, epigenetic regulation, and intercellular regulation. This review is expected to provide new targets for the treatment of atherosclerosis.
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Affiliation(s)
- Yonghang He
- The Second Clinical Medical College, Guangdong Medical University, Dongguan, 523808, China
| | - Tingting Liu
- The First Dongguan Affiliated Hospital, Guangdong Medical University, No. 42 Jiaoping Road, Tangxia Town, Dongguan City, Guangdong Province 523710, China; The Second Clinical Medical College, Guangdong Medical University, Dongguan, 523808, China.
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UPR modulation of host immunity by Pseudomonas aeruginosa in cystic fibrosis. Clin Sci (Lond) 2020; 134:1911-1934. [PMID: 32537652 DOI: 10.1042/cs20200066] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 12/11/2022]
Abstract
Cystic fibrosis (CF) is a progressive multiorgan autosomal recessive disease with devastating impact on the lungs caused by derangements of the CF transmembrane conductance regulator (CFTR) gene. Morbidity and mortality are caused by the triad of impaired mucociliary clearance, microbial infections and chronic inflammation. Pseudomonas aeruginosa is the main respiratory pathogen in individuals with CF infecting most patients in later stages. Despite its recognized clinical impact, molecular mechanisms that underlie P. aeruginosa pathogenesis and the host response to P. aeruginosa infection remain incompletely understood. The nuclear hormone receptor peroxisome proliferator-activated receptor (PPAR) γ (PPARγ), has shown to be reduced in CF airways. In the present study, we sought to investigate the upstream mechanisms repressing PPARγ expression and its impact on airway epithelial host defense. Endoplasmic reticulum-stress (ER-stress) triggered unfolded protein response (UPR) activated by misfolded CFTR and P. aeruginosa infection contributed to attenuated expression of PPARγ. Specifically, the protein kinase RNA (PKR)-like ER kinase (PERK) signaling pathway led to the enhanced expression of the CCAAT-enhancer-binding-protein homologous protein (CHOP). CHOP induction led to the repression of PPARγ expression. Mechanistically, we showed that CHOP induction mediated PPARγ attenuation, impacted the innate immune function of normal and ∆F508 primary airway epithelial cells by reducing expression of antimicrobial peptide (AMP) and paraoxanse-2 (PON-2), as well as enhancing IL-8 expression. Furthermore, mitochondrial reactive oxygen species production (mt-ROS) and ER-stress positive feedforward loop also dysregulated mitochondrial bioenergetics. Additionally, our findings implicate that PPARγ agonist pioglitazone (PIO) has beneficial effect on the host at the multicellular level ranging from host defense to mitochondrial re-energization.
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Circulating Levels of CILP2 Are Elevated in Coronary Heart Disease and Associated with Atherosclerosis. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:1871984. [PMID: 33204392 PMCID: PMC7652603 DOI: 10.1155/2020/1871984] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 08/23/2020] [Accepted: 10/01/2020] [Indexed: 01/18/2023]
Abstract
Methods and Results Circulating CILP2 levels (measured by ELISA) were compared to various insulin resistance- and atherosclerosis-related parameters in normal subjects and newly diagnosed CHD patients. THP-1 cells were cultured and treated with indicated stimulators. Western blots and RT-PCR were performed to examine protein and mRNA expressions. The results showed that there were significantly higher circulating CILP2 levels in CHD patients relative to healthy controls. Circulating CILP2 correlated positively with waist-hip ratio (WHR), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), HbA1c, homeostasis model assessment of insulin resistance (HOMA-IR), and Gensini scores. In an in vitro study, we found that CILP2 increased oxidatively modified LDL-stimulated lipid accumulation in THP-1 macrophages via the upregulation of CD36 expression. Inhibition of PPARγ signaling eliminated the CILP2 regulation of CD36 expression in THP-1 macrophages. CILP2 positively regulated CD36 transcription through PPARγ-mediated action on two peroxisome-proliferator-responsive elements (PPREs) binding sites of CD36 promoter, PPRE-G, and PPRE-J. Conclusions Our findings have uncovered a novel role for CILP2 in lipid uptake and foam cell formation. This role is mediated by CD36 through the activation of PPARγ pathway.
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Vangaveti V, Shashidhar V, Collier F, Hodge J, Rush C, Malabu U, Baune B, Kennedy RL. 9- and 13-HODE regulate fatty acid binding protein-4 in human macrophages, but does not involve HODE/GPR132 axis in PPAR-γ regulation of FABP4. Ther Adv Endocrinol Metab 2018; 9:137-150. [PMID: 29796244 PMCID: PMC5958425 DOI: 10.1177/2042018818759894] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 01/25/2018] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Both activation of monocytes and increased serum fatty acid binding protein-4 (FABP4) occur in diabetes and are associated with increased atherosclerosis. The oxidized lipid, 9-hydroxyoctadecadienoic acid (9-HODE) increases FABP4 in macrophages, and is a ligand for G protein-coupled receptor 132 (GPR132). We investigated the involvement of GPR132 in mediating the 9-, 13-HODE stimulation of FABP4 secretion, and whether GPR132 expression is increased in monocytes from patients with type 2 diabetes. METHODS The effects of siRNA silencing of GPR132 gene and of the PPAR-γ antagonist T0070907 were studied in THP-1 cells. Serum levels of FABP4 and other adipokines were measured in patients with diabetes, and monocyte subpopulations were analyzed using flow cytometry. GPR132 mRNA was quantified in isolated CD14+ cells. RESULTS 9-HODE and 13-HODE increased FABP4 expression in THP-1 monocytes and macrophages, and also increased GPR132 expression. Silencing of GPR132 did not influence the increase in FABP4 with 9-HODE, 13-HODE, or rosiglitazone (ROSI). By contrast, T0070907 inhibited the effect of all three ligands on FABP4 expression. Diabetic subjects had increased serum FABP4, and activated monocytes. They also expressed higher levels of GPR132 mRNA in CD14+ cells. CONCLUSIONS We conclude that GPR132 is an independent monocyte activation marker in diabetes, but does not contribute to PPAR-γ-mediated induction of FABP4 by HODEs.
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Affiliation(s)
| | | | - Fiona Collier
- School of Medicine, Deakin University, Victoria, Australia
| | - Jason Hodge
- School of Medicine, Deakin University, Victoria, Australia
| | - Catherine Rush
- College of Public Health, Medical & Vet Sciences, James Cook University, Queensland, Australia
| | - Usman Malabu
- College of Medicine and Dentistry, James Cook University, Queensland, Australia
| | - Bernhard Baune
- Department of Psychiatry, University of Adelaide, South Australia
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Voloshyna I, Kasselman LJ, Carsons SE, Littlefield MJ, Gomolin IH, De Leon J, Reiss AB. COX-2-dependent and independent effects of COX-2 inhibitors and NSAIDs on proatherogenic changes in human monocytes/macrophages. J Investig Med 2016; 65:694-704. [PMID: 27940550 DOI: 10.1136/jim-2016-000259] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2016] [Indexed: 12/14/2022]
Abstract
It is the second decade of controversy regarding the cardiovascular effects of cyclo-oxygenase-2 (COX-2) inhibitors. At this time, celecoxib is the only available COX-2-specific inhibitor for treatment of pain and inflammation. Therefore, the present study was designed primarily to determine the impact of celecoxib on cholesterol handling (uptake via scavenger receptors and efflux from the cells) and foam cell formation in human THP-1 macrophages, followed by comparison to rofecoxib and other non-steroidal anti-inflammatory drugs (NSAIDs). THP-1 human macrophages and peripheral blood mononuclear cells were incubated with: celecoxib, rofecoxib, naproxen (at 5, 10, 25 µM) and acetaminophen (0.5 mM, 1 mM)±oxidized low-density lipoprotein (oxLDL, 25 µg/mL). Scavenger receptors: CD36, LOX-1, SR-A1, and CXCL16 and cholesterol efflux proteins: ATP-binding cassette transporter (ABC) A1 and G1, and 27-hydroxylase were detected. The adhesion of monocytes to cultured endothelial cells with/ without COX-2 inhibitors/NSAIDs was also analyzed. The presence of celecoxib and rofecoxib (at high concentrations) significantly decreased expression of 27-hydroxylase and ABCA1, interfering with normal cholesterol outflow from macrophages. Acetaminophen and the non-specific COX inhibitor naproxen had no significant effect on these proteins. Only celecoxib had a profound effect on the class B scavenger receptor CD36 and the class E receptor LOX1. We demonstrate that in contrast to celecoxib, rofecoxib and naproxen increased adhesive properties of monocytes to endothelial cells. This work might contribute to our understanding of multiple mechanisms underlying elevated cardiovascular risk upon the use of COX-2 inhibitors and uncover new possibilities to enhance the safety profile of existing COX-2 inhibitors.
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Affiliation(s)
- Iryna Voloshyna
- Department of Medicine, Winthrop Research Institute and Winthrop-University Hospital, Mineola, New York, USA
| | - Lora J Kasselman
- Department of Medicine, Winthrop Research Institute and Winthrop-University Hospital, Mineola, New York, USA
| | - Steven E Carsons
- Department of Medicine, Winthrop Research Institute and Winthrop-University Hospital, Mineola, New York, USA
| | - Michael J Littlefield
- Department of Medicine, Winthrop Research Institute and Winthrop-University Hospital, Mineola, New York, USA
| | - Irving H Gomolin
- Department of Medicine, Winthrop Research Institute and Winthrop-University Hospital, Mineola, New York, USA
| | - Joshua De Leon
- Department of Medicine, Winthrop Research Institute and Winthrop-University Hospital, Mineola, New York, USA
| | - Allison B Reiss
- Department of Medicine, Winthrop Research Institute and Winthrop-University Hospital, Mineola, New York, USA
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Yuan M, Fu H, Ren L, Wang H, Guo W. Soluble CD40 ligand promotes macrophage foam cell formation in the etiology of atherosclerosis. Cardiology 2015; 131:1-12. [PMID: 25825037 DOI: 10.1159/000374105] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 01/08/2015] [Indexed: 11/19/2022]
Abstract
OBJECTIVE High levels of soluble CD40 ligand (sCD40L) in the circulation have been suggested as an important indicator of cardiovascular diseases such as atherosclerosis and acute coronary syndromes. In the present study, we explored the role of sCD40L in the formation of foam cells. METHODS Lipid deposition and foam cell formation was measured by high-performance liquid chromatography and Nile Red staining, respectively. Gene expressions were detected by quantitative real-time PCR and Western blot analysis. The interaction between CD40 and sCD40L were blocked by CD40 small interfering RNA or anti-CD40 antibody. RESULTS sCD40L significantly increased lipid deposition and foam cell formation associated with upregulation of scavenger receptor type A and CD36. Additionally, sCD40L increased adipocyte enhancer-binding protein 1 and cholesterol efflux, and activated NF-κB in macrophages. sCD40L promoted foam cell formation via CD40 ligation and disruption of the ligation between CD40 and CD40L either by small interfering RNA or by a blocking anti-CD40 antibody apparently inhibiting foam cell formation in response to sCD40L. CONCLUSION Our data suggests a novel insight into the role of sCD40L in foam cell formation during atherosclerosis, which further confirms the importance of sCD40L in atherosclerosis and as a target for the treatment of this disease.
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Affiliation(s)
- Ming Yuan
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
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Babaahmadi Rezaei H, Doosti M, Aminian M, Shabani P. Compare the effect of eicosapentaenoic acid and oxidized low-density lipoprotein on the expression of CD36 and peroxisome proliferator-activated receptor gamma. IRANIAN BIOMEDICAL JOURNAL 2014; 17:84-92. [PMID: 23567850 DOI: 10.6091/ibj.11322.2013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND There is evidence that CD36 promotes foam cell formation through internalizing oxidized LDL (ox-LDL) into macrophages; therefore, it plays a key role in pathogenesis of atherosclerosis. In addition, CD36 expression seems to be mediated by nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR-γ). The aim of the present study was to evaluate and compare the effect of PPAR-γ ligands, eicosapentaenoic acid (EPA) as an anti-atherogenic factor and ox-LDL as an atherogenic factor on CD36 expression. Mechanism of PPAR- γ action and its ligands in CD36 expression were also investigated. METHODS Raw 264.7 macrophage cell line was treated with ox-LDL (100 and 150 μg protein/LDL) and EPA (100 and 200 μM) for 24 and 48 hours in absence or presence of PPAR-γ inhibitor, T0070907. Quantitative real-time PCR and Western-blotting were used for analysis of gene and protein expression, respectively. RESULTS Raw 264.7 exposures to ox-LDL and EPA resulted in increased expression of CD36 mRNA and protein; however, mRNA and PPAR-γ protein were not up-regulated significantly. Pre-incubation of cells with T0070907 led to decreased expression of CD36 when treated with ox-LDL and EPA. CONCLUSION It was confirmed that both EPA and ox-LDL increased CD36 expression but not PPAR-γ, and also co-treatment with PPAR-γ inhibitor decreased CD36 expression. We concluded that up-regulation of CD36 depends on PPAR-γ activation and is not related to increased expression of PPAR-γ. Induction of CD36 by EPA showed that CD36 suppression is not the means by which ω-3 fatty acids (EPA) provide protection against formation of atherosclerotic plaque.
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Affiliation(s)
- Hossein Babaahmadi Rezaei
- Dept. of Clinical Biochemistry, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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Rios FJO, Ferracini M, Pecenin M, Koga MM, Wang Y, Ketelhuth DFJ, Jancar S. Uptake of oxLDL and IL-10 production by macrophages requires PAFR and CD36 recruitment into the same lipid rafts. PLoS One 2013; 8:e76893. [PMID: 24130805 PMCID: PMC3793910 DOI: 10.1371/journal.pone.0076893] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 08/28/2013] [Indexed: 01/24/2023] Open
Abstract
Macrophage interaction with oxidized low-density lipoprotein (oxLDL) leads to its differentiation into foam cells and cytokine production, contributing to atherosclerosis development. In a previous study, we showed that CD36 and the receptor for platelet-activating factor (PAFR) are required for oxLDL to activate gene transcription for cytokines and CD36. Here, we investigated the localization and physical interaction of CD36 and PAFR in macrophages stimulated with oxLDL. We found that blocking CD36 or PAFR decreases oxLDL uptake and IL-10 production. OxLDL induces IL-10 mRNA expression only in HEK293T expressing both receptors (PAFR and CD36). OxLDL does not induce IL-12 production. The lipid rafts disruption by treatment with βCD reduces the oxLDL uptake and IL-10 production. OxLDL induces co-immunoprecipitation of PAFR and CD36 with the constitutive raft protein flotillin-1, and colocalization with the lipid raft-marker GM1-ganglioside. Finally, we found colocalization of PAFR and CD36 in macrophages from human atherosclerotic plaques. Our results show that oxLDL induces the recruitment of PAFR and CD36 into the same lipid rafts, which is important for oxLDL uptake and IL-10 production. This study provided new insights into how oxLDL interact with macrophages and contributing to atherosclerosis development.
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Affiliation(s)
- Francisco J O Rios
- Department of Immunology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil ; BHF-Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
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Rios FJ, Koga MM, Pecenin M, Ferracini M, Gidlund M, Jancar S. Oxidized LDL induces alternative macrophage phenotype through activation of CD36 and PAFR. Mediators Inflamm 2013; 2013:198193. [PMID: 24062612 PMCID: PMC3767076 DOI: 10.1155/2013/198193] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Accepted: 07/22/2013] [Indexed: 12/14/2022] Open
Abstract
OxLDL is recognized by macrophage scavenger receptors, including CD36; we have recently found that Platelet-Activating Factor Receptor (PAFR) is also involved. Since PAFR in macrophages is associated with suppressor function, we examined the effect of oxLDL on macrophage phenotype. It was found that the presence of oxLDL during macrophage differentiation induced high mRNA levels to IL-10, mannose receptor, PPAR γ and arginase-1 and low levels of IL-12 and iNOS. When human THP-1 macrophages were pre-treated with oxLDL then stimulated with LPS, the production of IL-10 and TGF- β significantly increased, whereas that of IL-6 and IL-8 decreased. In murine TG-elicited macrophages, this protocol significantly reduced NO, iNOS and COX2 expression. Thus, oxLDL induced macrophage differentiation and activation towards the alternatively activated M2-phenotype. In murine macrophages, oxLDL induced TGF- β , arginase-1 and IL-10 mRNA expression, which were significantly reduced by pre-treatment with PAFR antagonists (WEB and CV) or with antibodies to CD36. The mRNA expression of IL-12, RANTES and CXCL2 were not affected. We showed that this profile of macrophage activation is dependent on the engagement of both CD36 and PAFR. We conclude that oxLDL induces alternative macrophage activation by mechanisms involving CD36 and PAFR.
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Affiliation(s)
- Francisco J Rios
- Department of Immunology, Institute of Biomedical Sciences, University of Sao Paulo, Avenida Professor Lineu Prestes 1730, ICB IV-Sala 140/146, 05508-900 Sao Paulo, SP, Brazil.
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Zhang L, Ovchinnikova O, Jönsson A, Lundberg AM, Berg M, Hansson GK, Ketelhuth DF. The tryptophan metabolite 3-hydroxyanthranilic acid lowers plasma lipids and decreases atherosclerosis in hypercholesterolaemic mice. Eur Heart J 2012; 33:2025-34. [DOI: 10.1093/eurheartj/ehs175] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Rios FJO, Koga MM, Ferracini M, Jancar S. Co-stimulation of PAFR and CD36 is required for oxLDL-induced human macrophages activation. PLoS One 2012; 7:e36632. [PMID: 22570732 PMCID: PMC3343035 DOI: 10.1371/journal.pone.0036632] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 04/04/2012] [Indexed: 11/18/2022] Open
Abstract
The oxidative process of LDL particles generates molecules which are structurally similar to platelet-activating factor (PAF), and some effects of oxidized LDL (oxLDL) have been shown to be dependent on PAF receptor (PAFR) activation. In a previous study, we showed that PAFR is required for upregulation of CD36 and oxLDL uptake. In the present study we analyzed the molecular mechanisms activated by oxLDL in human macrophages and the contribution of PAFR to this response. Human adherent monocytes/macrophages were stimulated with oxLDL. Uptake of oxLDL and CD36 expression were determined by flow cytometry; MAP kinases and Akt phosphorylation by Western blot; IL-8 and MCP-1 concentration by ELISA and mRNA expression by real-time PCR. To investigate the participation of the PI3K/Akt pathway, Gαi-coupled protein or PAFR, macrophages were treated with LY294002, pertussis toxin or with the PAFR antagonists WEB2170 and CV3988, respectively before addition of oxLDL. It was found that the addition of oxLDL to human monocytes/macrophages activates the PI3K/Akt pathway which in turn activates the MAPK (p38 and JNK). Phosphorylation of Akt requires the engagement of PAFR and a Gαi-coupled protein. The upregulation of CD36 protein and the uptake of oxLDL as well as the IL-8 production are dependent on PI3K/Akt pathway activation. The increased CD36 protein expression is dependent on PAFR and Gαi-coupled protein. Transfection studies using HEK 293t cells showed that oxLDL uptake occurs with either PAFR or CD36, but IL-8 production requires the co-transfection of both PAFR and CD36. These findings show that PAFR has a pivotal role in macrophages response to oxLDL and suggest that pharmacological intervention at the level of PAFR activation might be beneficial in atherosclerosis.
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Affiliation(s)
- Francisco J O Rios
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, Sao Paulo, Brazil.
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Peroxisome Proliferator-Activated Receptor-γ-Mediated Polarization of Macrophages in Leishmania Infection. PPAR Res 2012; 2012:796235. [PMID: 22448168 PMCID: PMC3289877 DOI: 10.1155/2012/796235] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 10/19/2011] [Indexed: 01/01/2023] Open
Abstract
Infection is the outcome of a contest between a pathogen and its host. In the disease leishmaniasis, the causative protozoan parasites are harbored inside the macrophages. Leishmania species adapt strategies to make the infection chronic, keeping a balance between their own and the host's defense so as to establish an environment that is favorable for survival and propagation. Activation of peroxisome proliferator-activated receptor (PPAR) is one of the tactics used. This ligand-activated nuclear factor curbs inflammation to protect the host from excessive injuries by setting a limit to its destructive force. In this paper, we report the interaction of host PPARs and the pathogen for visceral leishmaniasis, Leishmania donovani, in vivo and in vitro. PPAR expression is induced by parasitic infection. Leishmanial activation of PPARγ promotes survival, whereas blockade of PPARγ facilitates removal of the parasite. Thus, Leishmania parasites harness PPARγ to increase infectivity.
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Eicosapentaenoic Acid and Docosahexaenoic Acid Regulate Modified LDL Uptake and Macropinocytosis in Human Macrophages. Lipids 2011; 46:1053-61. [DOI: 10.1007/s11745-011-3598-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Accepted: 07/13/2011] [Indexed: 11/26/2022]
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Rios FJO, Gidlund M, Jancar S. Pivotal role for platelet-activating factor receptor in CD36 expression and oxLDL uptake by human monocytes/macrophages. Cell Physiol Biochem 2011; 27:363-72. [PMID: 21471725 DOI: 10.1159/000327962] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2011] [Indexed: 11/19/2022] Open
Abstract
The uptake of oxLDL by CD36 is not regulated by intracellular levels of cholesterol, leading to macrophage differentiation into foam cells which play a major role in atherosclerosis. Furthermore, oxLDL competes with PAF in macrophages for binding to PAF receptors (PAFR). Here we investigated the involvement of PAFR in CD36 expression and uptake of oxLDL by human monocytes/macrophages. Adherent peripheral blood mononuclear cells were treated with PAFR-antagonists (WEB2170, CV3988); inhibitors of ERK1/2 (PD98059), p38 (SB203580), JNK (SP600125) or diluents, before stimulation with oxLDL or PAF. After 24 h, uptake of FITC-oxLDL and expression of CD36 was determined by flow cytometry and phosphorylation of MAP-kinases by Western blot. It was shown that the uptake of oxLDL was reduced by PAFR antagonists. CD36 expression was up-regulated by oxLDL, an effect reversed by PAFR antagonists. The up-regulation of CD36 and oxLDL uptake both required MAP-kinases activation. The oxLDL-induced ERK1/2 and JNK but not p38 phosphorylation was reversed by PAFR-antagonists suggesting that oxLDL signalling involves PAFR dependent and independent pathways. In macrophages from PAFR(-/-) mice, oxLDL was unable to up-regulate CD36 expression and the oxLDL uptake was reduced compared to wild type. These results suggest that oxLDL interacts with PAFR in macrophages to increase CD36 expression and oxLDL uptake. Whereas pharmacological intervention at the level of PAFR would be beneficial in atherosclerosis remains to be determined.
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Affiliation(s)
- Francisco J O Rios
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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Levitan I, Volkov S, Subbaiah PV. Oxidized LDL: diversity, patterns of recognition, and pathophysiology. Antioxid Redox Signal 2010; 13:39-75. [PMID: 19888833 PMCID: PMC2877120 DOI: 10.1089/ars.2009.2733] [Citation(s) in RCA: 302] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Revised: 10/09/2009] [Accepted: 11/02/2009] [Indexed: 02/06/2023]
Abstract
Oxidative modification of LDL is known to elicit an array of pro-atherogenic responses, but it is generally underappreciated that oxidized LDL (OxLDL) exists in multiple forms, characterized by different degrees of oxidation and different mixtures of bioactive components. The variable effects of OxLDL reported in the literature can be attributed in large part to the heterogeneous nature of the preparations employed. In this review, we first describe the various subclasses and molecular composition of OxLDL, including the variety of minimally modified LDL preparations. We then describe multiple receptors that recognize various species of OxLDL and discuss the mechanisms responsible for the recognition by specific receptors. Furthermore, we discuss the contentious issues such as the nature of OxLDL in vivo and the physiological oxidizing agents, whether oxidation of LDL is a prerequisite for atherogenesis, whether OxLDL is the major source of lipids in foam cells, whether in some cases it actually induces cholesterol depletion, and finally the Janus-like nature of OxLDL in having both pro- and anti-inflammatory effects. Lastly, we extend our review to discuss the role of LDL oxidation in diseases other than atherosclerosis, including diabetes mellitus, and several autoimmune diseases, such as lupus erythematosus, anti-phospholipid syndrome, and rheumatoid arthritis.
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Affiliation(s)
- Irena Levitan
- Section of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
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Carvalho MDT, Vendrame CMV, Ketelhuth DFJ, Yamashiro-Kanashiro EH, Goto H, Gidlund M. High-Density Lipoprotein Inhibits the Uptake of Modified Low- Density Lipoprotein and the Expression of CD36 and FcγRI. J Atheroscler Thromb 2010; 17:844-57. [DOI: 10.5551/jat.3905] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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