Project description:This SuperSeries is composed of the following subset Series: GSE23303: Gene expression profiling of human atherosclerotic plaque: Laser capture microscopy of smooth muscle cells and macrophages GSE23304: Gene expression profiling of human atherosclerotic plaque: 101 peripheral plaques GSE24495: Gene expression profiling of human atherosclerotic plaque: Carotid plaque GSE24702: Gene expression profiling of human atherosclerotic plaque: 290 peripheral plaques Refer to individual Series
Project description:Macrophages represent a major immune cell population in atherosclerotic plaques and play central role in the progression of this lipid-driven chronic inflammatory disease. Targeting immunometabolism is proposed as a strategy to revert aberrant macrophage activation to improve disease outcome. Here, we show ATP citrate lyase (Acly) to be activated in inflammatory macrophages and human atherosclerotic plaques. We demonstrate that myeloid Acly deficiency induces a stable plaque phenotype characterized by increased collagen deposition and fibrous cap thickness, along with a smaller necrotic core. In-depth functional, lipidomic, and transcriptional characterization indicate deregulated fatty acid and cholesterol biosynthesis and reduced liver X receptor activation within the macrophages in vitro. This results in macrophages that are more prone to undergo apoptosis, whilst maintaining their capacity to phagocytose apoptotic cells. Together, our results indicate that targeting macrophage metabolism improves atherosclerosis outcome and we reveal Acly as a promising therapeutic target to stabilize atherosclerotic plaques.
Project description:Objective: Resident macrophages play an important role in atheromatous plaque rupture. The macrophage gene expression signature associated with plaque rupture is incompletely defined due to the complex cellular heterogeneity in the plaque. We aimed to characterise differential gene expression in resident plaque macrophages from ruptured and stable human atheromatous lesions. A cell-specific approach has the potential to address the question of gene expression differences between particular cell types in stable and unstable plaques with greater precision than approaches based on the study of whole plaques. Using laser micro-dissection, we isolated total RNA from macrophage-rich regions of stable and ruptured human atheromatous plaques derived from carotid endarterectomy samples which were comprehensively characterized using clinical, radiological and histological criteria, and carried out genome-wide gene expression profiling using microarrays. Results: The profiles were characteristic of activated macrophages. At a false discovery rate of 10%, 914 genes were differentially expressed between stable and ruptured plaques. The findings were confirmed in fourteen further stable and ruptured samples for a subset of eleven genes with the highest expression differences (p<0.05). Pathway analysis revealed that components of the PPAR/Adipocytokine signaling pathway were the most significantly upregulated in ruptured compared to stable plaques (p=5.4x10-7). Two key components of the pathway, fatty-acid binding-protein 4 (FABP4) and leptin, showed nine-fold (p=0.0086) and five-fold (p=0.0012) greater expression respectively in macrophages from ruptured plaques. Conclusions: We found differences in gene expression signatures between macrophages isolated from stable and ruptured human atheromatous plaques. Our findings indicate the involvement of FABP4 and leptin in the progression of atherosclerosis and plaque rupture, and suggest that down-regulation of PPAR/adipocytokine signaling within plaques may have therapeutic potential. Methods: We performed genome-wide expression analyses of isolated macrophage-rich regions of stable and ruptured human atherosclerotic plaques. Plaques present in carotid endarterectomy specimens were designated as stable or ruptured using clinical, radiological and histopathological criteria. Macrophage-rich regions were excised from 5 ruptured and 6 stable plaques by laser micro-dissection. Total RNA were subjected to two cycles of linear amplification. Transcriptional profiling was performed using Affymetrix HG-U133 plus 2.0 GeneChip arrays.
Project description:Recent studies suggest the presence of both âclassically activatedâ M1 and âalternatively activatedâ M2 macrophages in human atherosclerotic tissue, yet due to the lack of validated markers the reported localization patterns of these macrophage phenotypes within plaques are ambiguous. In the present study, we searched for markers that indisputably can identify differentiated M1 and M2 macrophages independently of stimuli that affect the activation status of the two subpopulations. We used these validated markers to assess the presence of M1 and M2 macrophages in different zones of human carotid artery atherosclerotic plaques obtained from 12 patients. Using microarray and qPCR technology we show that the frequently used macrophage subpopulation markers MCP-1 and CD206 do not discriminate between M1 and M2 macrophages. However, we confirm the subtype specificity of the classical M2 marker CD163 and we report that the genes INHBA and DSP (both M1) and SEPP1 and MARCKS (both M2) are highly suitable for macrophage phenotyping. mRNA expression of the pan-macrophage marker CD68 in the shoulder zones of the plaques and in adjacent tissue segments correlated positively with mRNA expression levels of SEPP1, MARCKS and CD163 (r=0.86, 0.94 and 0.96, and r= 0.86, 0.98 and 0.69, respectively) but not with the expression of the M1 markers DSP and INHBA. In contrast, mRNA expression of CD68 in the core of the plaques correlated positively with expression of DSP and INHBA (r=0.73 and 0.49) but not with SEPP1, MARCKS and CD163. These findings suggest that M1 macrophages predominate in the core of human carotid atherosclerotic plaques while M2 macrophages prevail at the periphery of the plaque. Keywords: Expression profiling by array Monocytes from healthy volunteers were differentiated into M1 and M2 macrophages by incubation with granulocyte-macrophage colony-stimulating factor (GM-CSF) or macrophage colony-stimulating factor (M-CSF), respectively. After 5 days cells were exposed to oxidized LDL. Total RNA was isolated and subjected to gene expression profiling.
Project description:Macrophages represent a major immune cell population in atherosclerotic plaques and play central role in the progression of this lipid-driven chronic inflammatory disease. Targeting immunometabolism is proposed as a strategy to revert aberrant macrophage activation to improve disease outcome. Here, we show ATP citrate lyase (Acly) to be activated in inflammatory macrophages and human atherosclerotic plaques. We demonstrate that myeloid Acly deficiency induces a stable plaque phenotype characterized by increased collagen deposition and fibrous cap thickness, along with a smaller necrotic core. In-depth functional, lipidomic, and transcriptional characterization indicate deregulated fatty acid and cholesterol biosynthesis and reduced liver X receptor (LXR) activation within the macrophages in vitro. This results in macrophages that are more prone to undergo apoptosis, whilst presenting increased phagocytosis of apoptotic cells. Together, our results indicate that targeting macrophage metabolism improves atherosclerosis outcome and we reveal Acly as a promising therapeutic target to stabilize atherosclerotic plaques.
Project description:Ischemia exists in many diseased tissues including arthritic joints, atherosclerotic plaques and malignant tumors. Macrophages accumulate in these sites and upregulate genes in response to the hypoxia present. We used microarrays to detail the hypoxia upregulated gene in human primary macrophages. Experiment Overall Design: Primary macrophages were differentiated for 7 days in vitro from human peripheral blood (monocyte-derived macrophages, MDMs) and were subjected to severe hypoxia (< 0.5% O2) or normoxia (20.9% O2) in 5% CO2 humidified multi-gas incubators.
Project description:Ischemia exists in many diseased tissues including arthritic joints, atherosclerotic plaques and malignant tumors. Macrophages accumulate in these sites and upregulate genes in response to the hypoxia present. We used microarrays to detail the hypoxia upregulated gene in human primary macrophages.