Project description:We report that bone marrow transplantation suppresses atherosclerosis by reducing LDL accumulation in the intima. Radiation exposure enhances endothelial endolysosomal trafficking and cholesterol efflux pathways, thus preventing reducing the abundance of LDL particles that traverse the endothelial layer to deposit in the sub-endothelial space.
Project description:Purpose: To investigate the effects of high cholesterol diet on the intimal transcriptome related to atherosclerosis. Methods: 3-week-old LDLR-/- male mice were fed a high cholesterol or low cholesterol diet for 9 weeks. Intimal RNA was extracted by injecting Trizol into the aorta and collecting the flow through for further processing. Results: Mice fed a high cholesterol revealed upregulation in atherosclerosis and immune/inflammatory related genes.
Project description:Background: Myeloid cells (MCs) reside in the aortic intima at regions predisposed to atherosclerosis. Systemic inflammation triggers reverse transendothelial migration (RTM) of intimal MCs into arterial blood, which orchestrates a protective immune response that clears intracellular pathogens from the arterial intima. Molecular pathways that regulate RTM remain poorly understood. Sphingosine-1-phosphate (S1P) is a lipid mediator that regulates immune cell trafficking by signaling via five G protein-coupled receptors (S1PRs). We investigated the role of S1P in the RTM of aortic intimal MCs. Methods: Intravenous injection of lipopolysaccharide (LPS) was used to model a systemic inflammatory stimulus that triggers RTM. CD11c+ intimal MCs in the lesser curvature of the ascending aortic arch were enumerated by en face confocal microscopy. Local gene expression was evaluated by transcriptomic analysis of microdissected intimal cells. Results: In wild-type C57BL/6 mice, LPS induced intimal cell expression of S1pr1, S1pr3, and sphingosine kinase 1 (Sphk1, a kinase responsible for S1P production). Pharmacological modulation of multiple S1PRs blocked LPS-induced RTM and modulation of S1PR1 and S1PR3 reduced RTM in an additive manner. Cre-mediated deletion of S1pr1 in MCs blocked LPS-induced RTM, confirming a role for myeloid-specific S1PR1 signaling. Global or hematopoietic deficiency of Sphk1 reduced plasma S1P levels, the abundance of CD11c+ MCs in the aortic intima and blunted LPS-induced RTM. In contrast, plasma S1P levels, the abundance of intimal MCs, and LPS-induced RTM were rescued in Sphk1-/- mice transplanted with Sphk1+/+ or mixed Sphk1 +/+ and -/- bone marrow. Stimulation with LPS increased endothelial permeability and intimal MC exposure to circulating factors such as S1P. Conclusions: Functional and expression studies support a novel role for S1P signaling in the regulation of LPS-induced RTM as well as the homeostatic maintenance of aortic intimal MCs. Our data provides insight into how circulating plasma mediators help orchestrate intimal MC dynamics.
Project description:Analysis of mouse thioglycollate-elicited peritoneal macrophages incubated in presence of acetylated low density lipoprotein (Ac-LDL) (120 μg/ml) for 24 h vs. mock-treated controls. Lipid accumulation in macrophages has profound effects on macrophage gene expression and contributes to the development of atherosclerosis. Angiopoietin-like protein 4 (ANGPTL4) is the most up-regulated gene in foamy macrophages and its absence in hematopoietic cells results in larger atherosclerotic plaques, characterized by bigger necrotic core areas and increased macrophage apoptosis.
Project description:Dysregulation of microRNAs (miRNAs) expression has been implicated in molecular genetics events leading to the progression and development of atherosclerosis. We hypothesized that miRNA expression profiles differ between baboons with low and high serum low-density lipoprotein cholesterol (LDL-C) concentrations in response to diet, and that a subset of these miRNAs regulate genes relevant to dyslipidemia and risk of atherosclerosis. We generated small RNA libraries from baboons differing in their LDL-C response to dietary fat and cholesterol (low LDL-C, n = 3; high LDL-C, n = 3) using liver biopsies collected before and after a high-cholesterol, high-fat (HCHF) challenge diet. We sequenced the libraries using Next-Generation Illumina sequencing methods, analyzed the data using mirTools software and identified 517 baboon miRNAs: 490 homologous to human and 27 novel miRNAs. HCHF diet elicited expression of more miRNAs compared to baseline (chow) diet for both low and high LDL-C baboons. Seventeen miRNAs exhibited significant differential expression in response to HCHF diet in high LDL-C baboons compared to nine miRNAs in low LDL-C baboons. Putative miRNA targets were identified with TargetScan/Base tools. miRNAs significantly targeted more genes in high LDL-C baboons compared to low LDL-C responders. Further, we identified miRNA isomers and other non-coding RNAs that were differentially expressed in response to the challenge diet.Our discovery of differentially expressed baboon miRNAs and their targets is a fundamental step in understanding the role of non-coding RNAs in the modulation of dsylipidemia.
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:LDL or Ox-LDL 200ug/ml, which showed no loss of viability after a 48 hour exposure, induced a physiological and pathological transcriptional response, respectively. LDL induced a downregulation of genes associated with cholesterol biosynthesis while ox-LDL induced transcriptional alterations in genes related to inflammation, matrix expansion, lipid metabolism and processing, and apoptosis. Pentraxin-3 was secreted into the culture medium after RPE cells were stimulated with ox-LDL, and immunohistochemically evident in Bruchs membrane of human macular samples with age-related macular degeneration. ARPE-19 cells exposed to 200ug/ml ox-LDL had a 38% apoptosis rate compared to less than 1% when exposed to LDL or untreated controls (p<0.0001). While LDL induced a physiologic response by RPE cells, a pathological phenotypic response was seen after treatment with oxidatively modified LDL. The transcriptional, biochemical, and functional data provide initial support of a role for the hypothesis that modified LDLs are one trigger for initiating events that contribute to the development of age-related macular degeneration. Keywords: treatment with non-treatment control Human ARPE-19 cells were exposed to LDL or oxidatively modified LDL (ox-LDL) for 48 hours for RNA extraction and hybridization on Affymetrix microarrays. We sought to determine whether retina, pigment epithelial cells develop a pathologic phenotype after exposure to low density lipoproteins (LDL) that are oxidatively modified.We have made two comparsions: LDL treatment versus non-treatment; ox-LDL treatment versus non-treatment.
Project description:We used microarrays to detail transcriptional changes in cultured human smooth muscle cells in response to acute and chronic 2-methoxyestradiol treatment 2-ME, an endogenous metabolite. of estradiol, not only exerts cytotoxic effects on cancer cells but it also protects against multiple proliferative disorders, including atherosclerosis and injury-induced intimal thickening Keywords: treatment vs. control Human aortic smooth muscle cells cultures with/without 2-methoxyestradiol (acute/chronic treatment)