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: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.
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.
2021-03-05 | MTBLS2159 | MetaboLights
Project description:Next-Generation Sequencing of ruptured atherosclerotic plaques
Project description:In order to identify potential new biomarkers of atherosclerotic plaque composition we performed a large scale analysis of gene expression patterns in human atherosclerotic lesions. Whole genome expression analysis of 101 peripheral plaques identified a robust gene signature (1514 genes) dominated by inflammatory processes, and cholesterol metabolism and storage genes. Specific pathways enriched in this signature included activation of the Toll-like receptor signaling pathway, T-cell activation, cholesterol efflux, oxidative stress response, inflammatory cytokine production, vasoconstriction and lysosomal activity. Analysis of gene expression in plaque micro-dissected material revealed that the signature is strongly up-regulated in macrophage-rich regions and down-regulated in regions with high smooth muscle cell content. A smaller qPCR biomarker panel and inflammatory composite score (ICS) were developed to facilitate clinical translation of discoveries from gene expression profiling. We found that ICS correlates with histological features related to plaque vulnerability. In addition, ICS is able to separate groups of plaques obtained from symptomatic and asymptomatic patients undergoing carotid endarerectomy. In summary, we identified a robust mRNA biomarker panel associated with histo-pathological as well as clinical hallmarks of vulnerable atherosclerotic plaque. This panel may be used as a diagnostic and prognostic tool in clinical setting to evaluate novel anti-atherosclerotic therapies. Laser captured smooth muscle cells and macrophages from carotid plaque sections (n=3) profiled in the Merck/Agilent 44k v1.1. The reference sample was a pool RNA from whole sections.
Project description:Inhibition of STAT5 was recently reported to reduce mouse atherosclerosis. However, the regulatory role of STAT5 isoforms STAT5A and STAT5B in human disease and more specifically in macrophages remains unknown. Here, we demonstrate reciprocal expression regulation of STAT5A and B in human atherosclerotic lesions. The former was highly upregulated in ruptured over stable plaque and correlated with macrophage presence, a finding that was corroborated by the high chromosomal accessibility of STAT5A but not B gene in plaque macrophages. Phosphorylated STAT5 correlated with macrophages confirming its activation status. As macrophage STAT5 is activated by GM-CSF, we studied the effects of its silencing in GM-CSF differentiated human macrophages. STAT5A knockdown blunted NF-kB pathway, phagocytosis, cholesterol metabolism, and apoptosis terms. These changes at transcriptional level could be confirmed at functional level, with significant increases in apoptosis and phagocytosis and decreases in lipid uptake and IL-6, IL8, and TNFa cytokine secretion after STAT5A knockdown. Finally, inhibition of general and isoform A specific STAT5 inhibitor significantly reduced the secretion of TNFa, IL-8 and IL-10 in ex vivo tissue slices of advanced human atherosclerotic plaques. In summary, we identify STAT5A as important determinant of macrophage functions and inflammation in the context of atherosclerosis and show its promise as therapeutic target for human atherosclerotic plaque inflammation.
Project description:Atherosclerotic plaque rupture is the etiology of ischemic stroke and myocardial infarction. Ribosome-depleted total RNA was sequenced from carotid plaques obtained from patients undergoing carotid endarterectomy with high-grade stenosis and either 1) a carotid-related ischemic cerebrovascular event within the previous 5 days ('recently ruptured,' n=6) or 2) an absence of a cerebrovascular event ('asymptomatic,' n=5). Examination of the differentially expressed genes supported the importance of inflammation and inhibition of proliferation and migration coupled with an increase in apoptosis. Thus, the transcriptome of recently ruptured plaques is enriched with transcripts associated with inflammation and fibrous cap thinning and support further examination of the role of B lymphocytes and interferons in atherosclerotic plaque rupture.
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.