Project description:Atherosclerosis is a serious and very common condition where plaque builds up inside arteries and that can lead to heart attack or stroke. The development and rupture of the plaque is a complex process, involving the interplay of many cell types and the extracellular environment. We performed RNAseq on stable and unstable regions dissected from fresh human carotid plaques obtained at carotid endarterectomy in symptomatic patients. The dissection of the plaques into stable and unstable regions was based on macroscopic appearance, with unstable regions characterised as the visible zone of plaque rupture.
Project description:The rupture of unstable atherosclerotic plaques, leading to debilitating or fatal thrombotic events, is a major health burden worldwide. Limited understanding as to the molecular drivers of plaque instability and rupture hinders efforts in diagnosis and treatment prior to thrombotic events. Utilising an advanced pre-clinical mouse model (Tandem stenosis (TS) model), which presents human-like unstable atherosclerotic disease, we apply high-end omic methods to characterize the molecular signatures associated with plaque instability in atherosclerotic arteries. Through quantitative proteomic profiling, we depict unique proteome signatures of unstable plaques compared to stable plaques and healthy arteries. Coupled with single-cell RNA-sequencing of leukocytes, we describe the heterodimer complex S100a8/S100a9 as unique to unstable plaque, with neutrophils implicated as the transcriptional drivers of S100a8/a9 expression. We confirm S100a9 expression in human carotid atherosclerotic plaques and we further utilise the TS pre-clinical model to pharmacologically inhibit S100a8/S100a9, resulting in plaque stabilisation. Thus, we establish the TS model as a sophisticated translational tool for the profiling of unstable atherosclerotic plaques and demonstrate that unstable and stable atherosclerosis are highly different disease entities.
Project description:Transcriptional profiling of stable and unstable atherosclerotic plaque segments from human carotid endatrerectomies Objective Comparison of gene expression in stable versus unstable atherosclerotic plaque may be confounded by interpatient variability. The aim of this study was to identify differences in gene expression between stable and unstable segments of plaque obtained from the same patient. Human carotid endarterectomy specimens were segmented and macroscopically classified using a morphological classification system. Two analytical methods, an intraplaque and an interplaque analysis, revealed 170 and 1916 differentially expressed genes, respectively using Affymetrix gene chip analysis. A total of 115 genes were identified from both analyses. The differential expression of 27 genes was also confirmed using quantitative-polymerase chain reaction on a larger panel of samples. Eighteen of these genes have not been associated previously with plaque instability, including the metalloproteinase, ADAMDEC1 (37-fold), retinoic acid receptor responder-1 (5-fold), and cysteine protease legumain (3-fold). Matrix metalloproteinase-9 (MMP-9), cathepsin B, and a novel gene, legumain, a potential activator of MMPs and cathepsins, were also confirmed at the protein level. The differential expression of 18 genes not previously associated with plaque rupture has been confirmed in stable and unstable regions of the same atherosclerotic plaque. These genes may represent novel targets for the treatment of unstable plaque or useful diagnostic markers of plaque instability. Differential gene expression in stable and unstable plaque was assessed by whole transcriptome analysis. Intraplaque analysis by QT-PCR confirmed the differential expression of 18 genes not associated previously with plaque rupture. These genes may represent novel targets for the treatment of unstable plaque or useful diagnostic markers of plaque instability
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:The rupture of unstable atherosclerotic plaques, leading to debilitating or fatal thrombotic events, are a major health concern worldwide. Limited understanding as to the molecular drivers of plaque destabilisation and rupture hinders efforts in diagnosis and treatment prior to thrombotic events. Using an advanced pre-clinical model (tandem stenosis), we characterise the molecular signatures associated with plaque instability in atherosclerotic vessels.
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: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: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:To investigate the expression profiles of miRNA in atherosclerotic plaques, the global features of miRNAs expression of three normal coronary artery tissues sample pools and three sample pools of advanced atherosclerosis plaques of coronary artery were studied using microarray technology,
Project description:Cardiovascular disease (CVD) is the leading cause of death, with atherosclerosis a major underlying cause. While often asymptomatic for decades, plaque destabilisation and rupture can arise suddenly and cause acute arterial occlusion or peripheral embolisation resulting in acute myocardial infarction, stroke and lower limb ischaemia. Hard plaques are typically considered as stable, and soft plaques as unstable. Extracellular matrix (ECM) remodelling can result in plaque destabilisation, but the mechanisms that drive the development of unstable lipid-rich plaques with a thin fibrous cap, versus stable fibrotic plaques with a thick cap, are not fully understood. We hypothesised that there would be significant differences in ECM composition between hard (stable) and soft (unstable and rupture-prone) plaques. We identified and quantified >46700 proteins, including 367 ECM proteins, with unprecedented coverage and high reproducibility. We identified 575 proteins with differential abundances between hard (stable) and soft (unstable) plaques. Proteins involved in inflammation and ECM remodeling, including multiple proteases were enriched, and ECM proteins decreased, in soft plaques. These data provide a unique insight into inflammatory mechanisms and ECM remodelling as an explanation for plaque destabilization. Furthermore they provide a first step towards identifying circulating biomarkers for individualised risk profiling of arteriosclerosis.