Project description:Atherosclerosis is an inflammatory disease linked to elevated blood cholesterol levels. Despite ongoing advances in the prevention and treatment of atherosclerosis 1, cardiovascular disease remains the leading cause of death worldwide 2. Continuous retention of apolipoprotein B-containing lipoproteins in the subendothelial space causes a local overabundance of free cholesterol. Since cholesterol accumulation and deposition of cholesterol crystals (CCs) triggers a complex inflammatory response 3 4, we tested the therapeutic potential of increasing cholesterol solubility in experimental atherogenesis. Here we show that treatment of murine atherosclerosis with the cyclic oligosaccharide 2-hydroxypropyl-β-cyclodextrin (CD), a compound that solubilizes lipophilic substances, reduced atherosclerotic plaque size, cholesterol crystal load and promoted plaque regression even under continuing Western diet. CD solubilized CCs and promoted cholesterylester and oxysterol production in macrophages leading to liver X receptor (LXR)-mediated transcriptional reprogramming. CD increased cholesterol efflux from macrophages and substantially augmented reverse cholesterol transport in vivo. Furthermore, CD reduced proinflammatory cytokines in vivo and decreased macrophage responsiveness towards TLR and inflammasome activation. Since CD treatment in humans is safe and CD beneficially affects key pathogenetic factors in atherogenesis it may thus be used clinically to prevent or treat human atherosclerosis .
Project description:Atherosclerosis is an inflammatory disease linked to elevated blood cholesterol levels. Despite ongoing advances in the prevention and treatment of atherosclerosis 1, cardiovascular disease remains the leading cause of death worldwide 2. Continuous retention of apolipoprotein B-containing lipoproteins in the subendothelial space causes a local overabundance of free cholesterol. Since cholesterol accumulation and deposition of cholesterol crystals (CCs) triggers a complex inflammatory response 3 4, we tested the therapeutic potential of increasing cholesterol solubility in experimental atherogenesis. Here we show that treatment of murine atherosclerosis with the cyclic oligosaccharide 2-hydroxypropyl-β-cyclodextrin (CD), a compound that solubilizes lipophilic substances, reduced atherosclerotic plaque size, cholesterol crystal load and promoted plaque regression even under continuing Western diet. CD solubilized CCs and promoted cholesterylester and oxysterol production in macrophages leading to liver X receptor (LXR)-mediated transcriptional reprogramming. CD increased cholesterol efflux from macrophages and substantially augmented reverse cholesterol transport in vivo. Furthermore, CD reduced proinflammatory cytokines in vivo and decreased macrophage responsiveness towards TLR and inflammasome activation. Since CD treatment in humans is safe and CD beneficially affects key pathogenetic factors in atherogenesis it may thus be used clinically to prevent or treat human atherosclerosis .
Project description:Atherosclerosis is an inflammatory disease linked to elevated blood cholesterol levels. Since cholesterol retention and cholesterol crystals in arterial walls are key pathogenetic factors for atherogenesis, we assessed the therapeutic potential of increasing cholesterol solubility in vivo. Here we show that treatment of murine atherosclerosis with the cyclic oligosaccharide 2-hydroxypropyl-β-cyclodextrin (CD), a compound that solubilizes lipophilic substances, reduced atherosclerotic plaque size, cholesterol crystal (CC) load and promoted plaque regression even under continuing Western diet. CD solubilized CC and promoted cholesterylester and oxysterol production in macrophages leading to liver X receptor-mediated transcriptional reprogramming with increased cholesterol efflux and decreased inflammation. CD treatment may thus be used to increase cholesterol solubility and clearance to prevent or treat atherosclerosis.
Project description:Nuclear receptors are important conduits between environmental cues and gene expression, but the molecular events governing spatial variation in their responses remain poorly understood. Here we outline an important role for a non-coding RNA in modulating the cell type-specific actions of the cholesterol-activated nuclear receptor LXR. LXR regulates the expression of genes involved in responses to excess cholesterol and has been causally linked to the pathogenesis and treatment of prevention and atherosclerosis in animals. We identify the lncRNA MeXis as an amplifier of LXR-dependent transcription of the critical cholesterol efflux gene Abca1. MeXis interacts with and guides the promoter binding of the nuclear receptor transcriptional coactivator DDX17. Loss of MeXis in murine immune cells has a marked impact on chromosome architecture at the Abca1 locus, impairs cellular responses to cholesterol overload, and accelerates the development of atherosclerosis. Our findings define MeXis as a lncRNA gatekeeper that modifies the actions of LXR in lipid-dependent control of macrophage gene expression. This has important implications for mechanisms that underlie spatial activation patterns of nuclear receptors. Our work opens a new gateway to targeting reverse cholesterol transport since it is conceivable that therapeutic approaches that enhance MeXis activity might reduce foam cell formation and atherogenesis.
Project description:Nuclear receptors are important conduits between environmental cues and gene expression, but the molecular events governing spatial variation in their responses remain poorly understood. Here we outline an important role for a non-coding RNA in modulating the cell type-specific actions of the cholesterol-activated nuclear receptor LXR. LXR regulates the expression of genes involved in responses to excess cholesterol and has been causally linked to the pathogenesis and treatment of prevention and atherosclerosis in animals. We identify the lncRNA MeXis as an amplifier of LXRdependent transcription of the critical cholesterol efflux gene Abca1. MeXis interacts with and guides the promoter binding of the nuclear receptor transcriptional coactivator DDX17. Loss of MeXis in murine immune cells has a marked impact on chromosome architecture at the Abca1 locus, impairs cellular responses to cholesterol overload, and accelerates the development of atherosclerosis. Our findings define MeXis as a lncRNA gatekeeper that modifies the actions of LXR in lipid-dependent control of macrophage gene expression. This has important implications for mechanisms that underlie spatial activation patterns of nuclear receptors. Our work opens a new gateway to targeting reverse cholesterol transport since it is conceivable that therapeutic approaches that enhance MeXis activity might reduce foam cell formation and atherogenesis
Project description:Lipid rafts are cholesterol-rich cell signaling platforms and their physiological role can be explored by cholesterol depletion. To dress a global picture of transcriptional changes ongoing after lipid raft disruption, we performed whole-genome expression profiling in epidermal keratinocytes, a cell type which synthesizes its cholesterol in situ. We used microarrays to identify transcriptional changes in gene expression of cholesterol-depleted keratinocytes. Cholesterol depletion by methyl-beta-cyclodextrin disrupts the organization of lipid rafts, which are cholesterol- and sphingolipid-rich membrane microdomains. Transcript levels were measured in autocrine confluent cultures of normal human epidermal keratinocytes were either left untreated (Ctrl), cholesterol-depleted for 1h with 7.5mM methyl-beta-cyclodextrin (MBCD), or mock cholesterol-depleted for 1h with 7.5mM cholesterol-charged methyl-beta-cyclodextrin complexes (MBCD/chol) (Mock cholesterol depletion is a suppementary negative control as this treatment does not extract cholesterol from cell membranes). Samples are analysed either immediately after the treatment (R0h) or after recovery times of 1h (R1h) respectively 8h (R8h). in total 9 samples are analysed and no replicates are performed.
Project description:Endothelial progenitor cells (EPCs) promote the maintenance of the endothelium by secreting vasoreparative factors. A population of EPCs known as early outgrowth cells (EOCs) are being investigated as novel cell-based therapies for the treatment of cardiovascular disease. We previously demonstrated that the absence of liver x receptors (LXRs) is detrimental to the formation and function of EOCs under hypercholesterolemic conditions. Here, we investigate whether LXR activation in EOCs is beneficial for the treatment of atherosclerosis. EOCs were differentiated from the bone marrow of wildtype (WT) and LXR-knockout (Lxrαβ-/-) mice in the presence of vehicle or LXR agonist (GW3965). This data set is a proteomic comparison of EPCs at day 1 after isolation and day 9 of GW39565 treatment compared to day 9 of vehicle treatment.