Project description:Atherosclerosis is the leading underlying cause of death worldwide. We reported a mouse model of atherosclerosis regression that involves transplanting an atherosclerotic aortic arch into a normolipidemic mouse. There, emigration of plaque foam cells occurred in a CCR7 (dendritic cell migration factor) dependent manner. It was obvious, though, that other pathways are likely to be involved in this process. We therefore performed microarrays on laser captured macrophages isolated from the progression and regression environments. This yielded two major findings. Firstly, genes associated with the contractile apparatus (such as actin and myosin) that are responsible for cellular movement were differentially up-regulated under regression conditions with members of the cadherin family (serves in adhesion functions) being significantly down-regulated. Secondly, the most highly up-regulated gene under regression was arginase I, a classical marker of the M2 alternative activated macrophage. Further examination revealed that regression was characterized by macrophages displaying other M2 markers such as CD163, C-lectin receptor, mannose receptor, and Fizz-1. In addition, we applied recently introduced local causal pathway discovery methods to our microarray data that revealed that genes such as vinculin and ApoCII may play a role in the pathophysiology of atherosclerosis regression. Ultimately, the insights gained from the regression model and the different modes of analyses should lead to new therapeutic targets against cardiovascular disease. We performed microarrays on laser captured macrophages isolated from aortic arch from mouse in atherosclerosis progression and regression environments (C57Bl/6, ApoE -/-). Study was performed in two batches, with three treatment groups each: progression, regression and baseline. Profiled in the Merck/Agilent 3.0
Project description:In atherosclerosis progression and regression, monocytes or monocyte-derived macrophages are the major immune cells in the plaque. It is important to understand the fate and characteristics of monocyte/macrophage during the plaque progression and regression. To characterize the fate of monocytes/macrophages, we performed single cell RNA sequencing of fate-mapped aortic CX3CR1-derived monocytes/macrophages from Cx3cr1CreERT2-IRES-YFP/+Rosa26floxed-tdTomato/+ mice with AAV-PCSK9 injection and fed a Western Diet. The single cell RNA-seq analyses revealed the heterogeneity of aortic macrophages and identified a stem-like cell cluster in atherosclerotic aorta.
Project description:Regression of atherosclerosis is an important clinical goal, however the pathways that mediate the resolution of atherosclerotic inflammation and reversal of plaques are poorly understood. Regulatory T cells (Tregs) have been shown to be atheroprotective, however numbers of these immunosuppressive cells decrease with disease progression. Using multiple independent mouse models of atherosclerosis regression, we demonstrate that an increase in plaque Tregs is a common signature of regressing plaques. To test if Tregs are required for the resolution of atherosclerotic inflammation and plaque regression during lipid-lowering therapy, we combined CD25 monoclonal antibody (PC61 mAb)-mediated Treg depletion with single-cell RNA-sequencing of immune cells in the plaque and conventional analyses of atherosclerosis. Single cell RNA-sequencing revealed that Tregs from aortic plaques shared some similarity with splenic Tregs, but were distinct from skin and colon Tregs supporting recent findings of tissue-dependent Treg heterogeneity. Furthermore, Tregs from progressing plaques expressed markers of natural Tregs derived from the thymus, whereas Tregs in regressing plaques lacked Nrp1 and Helios expression, suggesting that they are induced in the periphery during lipid lowering. Treatment of atherosclerotic mice with PC61 mAb effectively depleted Tregs in the blood and peripheral tissues, including plaques, and blocked the regression of atherosclerosis induced by apoB anti-sense oligonucleotides. Morphometric analyses revealed that control antibody-treated mice showed a 40% decrease in plaque burden and macrophage content under regression conditions, whereas PC61 mAb-treated mice showed no change in plaque size or inflammatory cell content compared to baseline. Moreover, Treg depletion enhanced inflammatory signaling and blocked tissue reparative functions of macrophages in the regressing plaque, including M2-polarization, efferocytosis and sensing of specialized pro-resolving lipid mediators. Together, these data establish essential roles for Tregs in the resolution of atherosclerotic inflammation and plaque remodeling during regression.
Project description:The project was designed to identify genes with an altered expression in macrophages from subjects with atherosclerosis compared to macrophages from control subjects. Experiment Overall Design: We used monocyte-derived macrophages from peripheral blood cultured in the absence or presence of oxidized LDL, baseline macrophages or foam cells. The macrophages were obtained from 15 subjects with subclinical atherosclerosis and a family history of CHD. Macrophages from 15 age and sexmatched subjects with no atherosclerosis and no family history of CHD were used as control.
Project description:Atherosclerosis is the leading underlying cause of death worldwide. We reported a mouse model of atherosclerosis regression that involves transplanting an atherosclerotic aortic arch into a normolipidemic mouse. There, emigration of plaque foam cells occurred in a CCR7 (dendritic cell migration factor) dependent manner. It was obvious, though, that other pathways are likely to be involved in this process. We therefore performed microarrays on laser captured macrophages isolated from the progression and regression environments. This yielded two major findings. Firstly, genes associated with the contractile apparatus (such as actin and myosin) that are responsible for cellular movement were differentially up-regulated under regression conditions with members of the cadherin family (serves in adhesion functions) being significantly down-regulated. Secondly, the most highly up-regulated gene under regression was arginase I, a classical marker of the M2 alternative activated macrophage. Further examination revealed that regression was characterized by macrophages displaying other M2 markers such as CD163, C-lectin receptor, mannose receptor, and Fizz-1. In addition, we applied recently introduced local causal pathway discovery methods to our microarray data that revealed that genes such as vinculin and ApoCII may play a role in the pathophysiology of atherosclerosis regression. Ultimately, the insights gained from the regression model and the different modes of analyses should lead to new therapeutic targets against cardiovascular disease.