Dataset Information

Oxidized LDL triggers changes in oxidative stress and inflammatory biomarkers in human macrophages.

ABSTRACT: Oxidized low-density lipoprotein (oxLDL) is a well-recognized proatherogenic particle that functions in atherosclerosis. In this study, we established conditions to generate human oxLDL, characterized according to the grade of lipid and protein oxidation, particle size and oxylipin content. The induction effect of the cellular proatherogenic response was assessed in foam cells by using an oxLDL-macrophage interaction model. Uptake of oxLDL, reactive oxygen species production and expression of oxLDL receptors (CD36, SR-A and LOX-1) were significantly increased in THP-1 macrophages. Analyses of 35 oxylipins revealed that isoprostanes (IsoP) and prostaglandins (PGs) derived from the oxidation of arachidonic, dihomo gamma-linolenic and eicosapentaenoic acids were strongly and significantly induced in macrophages stimulated with oxLDL. Importantly, the main metabolites responsible for the THP1-macrophage response to oxLDL exposure were the oxidative stress markers 5-epi-5-F2t-IsoP, 15-E1t-IsoP, 8-F3t-IsoP and 15-keto-15-F2t-IsoP as well as inflammatory markers PGDM, 17-trans-PGF3?, and 11?-PGF2?, all of which are reported here, for the first time, to function in the interaction of oxLDL with THP-1 macrophages. By contrast, a salvage pathway mediated by anti-inflammatory PGs (PGE1 and 17-trans-PGF3?) was also identified, suggesting a response to oxLDL-induced injury. In conclusion, when THP-1 macrophages were treated with oxLDL, a specific induction of biomarkers related to oxidative stress and inflammation was triggered. This work contributes to our understanding of initial atherogenic events mediated by oxLDL-macrophage interactions and helps to generate new approaches for their modulation.

SUBMITTER: Lara-Guzman OJ

PROVIDER: S-EPMC5723280 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature

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Oxidized LDL triggers changes in oxidative stress and inflammatory biomarkers in human macrophages.

Lara-Guzmán Oscar J OJ Gil-Izquierdo Ángel Á Medina Sonia S Osorio Edison E Álvarez-Quintero Rafael R Zuluaga Natalia N Oger Camille C Galano Jean-Marie JM Durand Thierry T Muñoz-Durango Katalina K

Redox biology 20171122

Oxidized low-density lipoprotein (oxLDL) is a well-recognized proatherogenic particle that functions in atherosclerosis. In this study, we established conditions to generate human oxLDL, characterized according to the grade of lipid and protein oxidation, particle size and oxylipin content. The induction effect of the cellular proatherogenic response was assessed in foam cells by using an oxLDL-macrophage interaction model. Uptake of oxLDL, reactive oxygen species production and expression of ox ...[more]

PMID: 29195136

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Project description:Neutrophil extracellular traps (NETs) are web-like structures, which are released upon neutrophil activation. It has previously been demonstrated that NETs are present in atherosclerotic lesions of both humans and animal models thus playing a decisive role in atherosclerosis. Besides, macrophages have a crucial role in disease progression, whereby classically activated M1 macrophages sustain inflammation and alternatively activated M2 macrophages display anti-inflammatory effects. Although NETs and macrophages were found to colocalize in atherosclerotic lesions, the impact of NETs on macrophage function is not fully understood. In the present study, we aimed to investigate the effect of NETs on human and murine macrophages in respect to the expression of pro-inflammatory cytokines, matrix metalloproteinases (MMPs) and uptake of oxidized LDL (oxLDL) in vitro. Human THP-1 and murine bone marrow-derived macrophages were cultured under M1 (LPS + IFN-γ)- and M2a (IL-4)-polarizing culture conditions and treated with NETs. To mimic intraplaque regions, cells were additionally cultured under hypoxic conditions. NETs significantly increased the expression of IL-1β, TNF-α and IL-6 in THP-M1 macrophages under normoxia but suppressed their expression in murine M1 macrophages under hypoxic conditions. Notably, NETs increased the number of oxLDL-positive M1 and M2 human and murine macrophages under normoxia, but did not influence formation of murine foam cells under hypoxia. However, oxLDL uptake did not strongly correlate with the expression of the LDL receptor CD36. Besides, upregulated MMP-9 expression and secretion by macrophages was detected in the presence of NETs. Again, hypoxic culture conditions dampened NETs effects. These results suggest that NETs may favor foam cell formation and plaque vulnerability, but exert opposite effects in respect to the inflammatory response of human and murine M1 macrophages. Moreover, effects of NETs on macrophages' phenotype are altered under hypoxia.

Project description:The function of human circulating proangiogenic cells (PACs) has been described extensively. However, little focus has been placed on understanding how these cells differ in their functions in the presence of microenvironments mimicking vascular inflammation. We hypothesized that exposure to proinflammatory cytokines or the oxLDL, an autoantigen abundant in advanced atherosclerotic plaques, converts PACs into immune-modulating/proinflammatory cells. Hence, we examined the effect of oxLDL and inflammatory stimuli on their phenotype by use of a functional genomics model based on secretome and whole genome transcriptome profiling. PACs obtained from culturing a PBMC fraction in angiogenic medium were primed with DC differentiation cytokines for 3 days and then exposed to proinflammatory cytokines or oxLDL for 2 days. Under these conditions, PACs converted into APCs (APCcy and APCox, respectively), expressed maturation markers CD80 and CD83, and showed an up-regulation of CD86. APCcy and APCox induced a robust T cell BrdU incorporation. Despite a similar ability to induce lymphocyte proliferation, APCcy and APCox differed for the secretory pathway and mRNA expression. Analysis of the differentially expressed genes identified 4 gene "clusters", showing reciprocal modulation in APCcy vs. APCox justifying, according to functional genomics analyses, a different putative function of the cells in antigen processing. Together, these data show that treatment with inflammatory cytokines or oxLDL converts human PAC phenotype and function into that of APCs with similar lymphocyte-activating ability but distinct maturation degree and paracrine functions. PBMC-derived PACs were committed with GM-CSF and IL-4 to a dendritic phenotype, and then exposed to proinflammatory cytokines (IL-1β and TNF-α) or to the oxidized form of LDL (oxLDL). Functional assays and whole genome gene expression profiling were performed both on PACs (n=6) and or resulting cytokine- (APCcy, n=6) and oxLDL-induced APCs (APCox, n=6). RNA was reverse transcribed, labeled, and linearly amplified, and then hybridized to HumanHT-12 v.4 Expression BeadChip microarrays. To estimate technical variability, ≈20% of the samples (n=4) were hybridized in duplicate.

Dataset Information

Oxidized LDL triggers changes in oxidative stress and inflammatory biomarkers in human macrophages.

Publications

Oxidized LDL triggers changes in oxidative stress and inflammatory biomarkers in human macrophages.

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