Lack of apoA-I in apoEKO mice causes skin xanthomas, worsening of inflammation and increased coronary atherosclerosis in the absence of hyperlipidemia
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE202237 | GEO | 2022/05/07
REPOSITORIES: GEO
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Project description:HDL particles are known to possess several anti-atherogenic properties that include the removal of excess cholesterol from peripheral tissues, the maintenance of endothelial integrity, antioxidant and antiinflammatory activities. ApoA-I overexpression in apoE-deficient (EKO) mice has been shown to increase HDL levels and to strongly reduce atherosclerosis development. The aim of the study was to investigate gene expression patterns associated with atherosclerosis development in the aorta of EKO mice and how HDL plasma levels relate to gene expression patterns at different stages of atherosclerosis development and with different dietary treatments. Methods Eight weeks old EKO mice, EKO mice overexpressing human apoA-I (EKO/hA-I) and wild-type mice as controls were fed either Chow or Western diet for 6 or 22 weeks. Cholesterol distribution among lipoproteins was evaluated and atherosclerosis of the aorta was quantified. High-throughput sequencing technologies were used to analyse the transcriptome of the aorta of the three genotypes in each experimental condition. Results: In addition to the well-known activation of inflammation and immune response, the impairment of sphingolipid metabolism, phagosome-lysosome system and osteoclast differentiation emerged as relevant players in atherosclerosis development. The reduced atherosclerotic burden in the aorta of EKO mice expressing high levels of apoA-I was accompanied by a reduced activation of the immune system markers, as well as reduced perturbation of lysosomal activity and a better regulation of the sphingolipid synthesis pathway Conclusions. ApoA-I modulates atherosclerosis development in the aorta of EKO mice affecting the expression of pathways additional to those associated with inflammation and immune response
2020-12-22 | GSE163657 | GEO
Project description:Specific mutations in Apolipoprotein A-I (ApoA-I) of high-density lipoprotein (HDL) are responsible for a late-onset systemic amyloidosis. Carriers do not exhibit increased cardiovascular disease risk despite reduced levels of ApoA-I/ HDL-cholesterol. To explain this paradox, we show that the HDL particle profile of L75P and L174S patients presents a higher relative abundance of the 8.4 nm vs 9.6 nm particles, and that serum from patients, as well as reconstituted 8.4 and 9.6 nm HDL particles (rHDL), possess increased capacity to catalyze cholesterol efflux from macrophages. Synchrotron radiation circular dichroism and hydrogen-deuterium exchange revealed that the variants in 8.4 nm rHDL have altered secondary structure composition and display a more flexible binding to lipids compared to their native counterpart. The reduced HDL-cholesterol levels of patients carrying ApoA-I amyloidogenic variants are thus balanced by higher proportion of small, dense HDL particles and better cholesterol efflux due to altered, region-specific protein structure dynamics.
2020-11-20 | PXD021266 | Pride
Project description:Purpose: To clarify cellular and molecular mechanisms underlying impaired post-ischemic adaptive vascular responses and to evaluate reconstituted HDL (rHDL)-ApoA-I nanotherapy to rescue the defect in type 2 diabetic (T2DM) mouse model of hindlimb ischemia (HLI). Methods: Mice with beta-cell specific over-expression of insulin-like growth factor-2 in atherosclerotic background (IGF-II/ LDLR-/-ApoB100/100) with T2DM features were used in the study with C57BL/6J mice fed with a regular chow-diet (R36, Lactamin) serving as controls. Mice aged between 16 to 20 weeks were used in the study . Mice were anaesthetized with 1.5-2% isoflurane/air mixture during the surgical procedure. Hair was removed from the operation site and cleaned with sterile water. Single incision was made just above medial thigh and superficial femoral artery was separated from femoral vein and nerve. HLI was induced by unilateral ligation of femoral artery distal to the origin of the profunda femoral artery. The skin was closed with interrupted silk sutures. Mice were were administered with reconstituted ApoA-I nanoparticles with phosphatidyl serine core (rHDL) intravenously starting 2 days post-HLI with doses every 2 days until scarification with Saline injections serving as controls. Adductors muscle aortic endothelial cells (AECs) and Ischemic muscle Macrophages and Endothelial Cells (ECs) were isolated using a combination of magnetic assisted cell sorting and flow Cytometry using Macrophage (F4/80) and EC (CD-31) specific markers. Total RNA isolated from FACS sorted cells were used for RNA seq library preparation. Results: Cell-specific gene expression, flow cytometry and immunohistochemistry revealed a persistent Macrophage and Endothelial cell inflammation and a reduced anti-inflammatory M2-macrophage activation associated with impaired collateral remodelling and sprouting angiogenesis in T2DM mice. Furthermore, reconstituted HDL (rHDL)- ApoA-I was found to rescue impaired collateral remodelling and angiogenesis in T2DM mice through modulating EC and macrophage phenotypes. Conclusions: Our results suggest that an impaired collateral remodelling and sprouting angiogenesis in T2DM mice after HLI is associated with a persistent EC and macrophage inflammation and a reduced activation of anti-inflammatory M2-macrophage. Skewing the macrophage phenotype towards the pro-arteriogenic and pro-angiogenic anti-inflammatory M2-macrophages using reconstituted HDL (rHDL)-ApoA-I nanotherapy may serve as a potential therapeutic modality for T2DM PAD.
2023-01-30 | GSE197392 | GEO
Project description:Apolipoprotein A-I is well known to play a role in cholesterol efflux, but our studies suggest that apoA-I may also induce proinflammatory signaling. The molecular mechanisms behind apoA-I-mediated proinflammatory signaling have not yet been explored, nor has the link between this signaling and cholesterol efflux. We hypothesize that apoA-I is a novel TLR agonist, signaling through the MyD88 proinflammatory signaling adaptor to induce cytokines. Microarray analysis confirmed that a suite of pro-inflammatory genes are induced by apoA-I with varying dependence upon MyD88, and that MyD88 regulates >6% of the apoA-I-induced transcriptome.
2010-06-15 | GSE13772 | GEO
Project description:Lack of apoA-I in apoEKO mice causes skin xanthomas, worsening of inflammation and increased coronary atherosclerosis in the absence of hyperlipidemia
| PRJNA835106 | ENA
Project description:Apolipoprotein A-I (apoA-I) is cross-linked and dysfunctional in human atheroma. Although multiple mechanisms of apoA-1 cross-linking have been demonstrated in vitro, the in vivo mechanisms of cross-linking are not well established. We have recently demonstrated the highly selective and efficient modification of high-density lipoprotein (HDL) apoproteins by endogenous oxidized phospholipids (oxPLs), including oxoalkenal phospholipids. In the current study, we report that oxoalkenal phospholipids effectively cross-link apoproteins in HDL. We further demonstrate that cross-linking impairs the cholesterol efflux mediated by apoA-I or HDL3 in vitro and in vivo. Using LC-MS/MS analysis, we analyzed the pattern of apoprotein cross-linking in isolated human HDL either by synthetic oxoalkenal phospholipids or by oxPL generated during HDL oxidation in plasma by the physiologically relevant MPO-H2O2-NO2- system. We found that five histidine residues in helices 5-8 of apoA-I are preferably cross-linked by oxPL, forming stable pyrrole adducts with lysine residues in the helices 3-4 of another apoA-I or in the central domain of apoA-II. We also identified cross-links of apoA-I and apoA-II with two minor HDL apoproteins, apoA-IV and apoE. We detected a similar pattern of apoprotein cross-linking in oxidized murine HDL. We further detected oxPL cross-link adducts of HDL apoproteins in plasma and aorta of hyperlipidemic LDLR-/- mice, including cross-link adducts of apoA-I His-165--apoA-I Lys-93, apoA-I His-154--apoA-I Lys-105, apoA-I His-154--apoA-IV Lys-149, and apoA-II Lys-30/apoE His-227. These findings suggest an important mechanism that contributes to the loss of HDL's atheroprotective function in vivo.
2019-12-13 | MSV000084689 | MassIVE
Project description:Human mesenchymal stem cells are differentiated into osteoblasts in the presence or absence of ApoA-I treatment, the global gene profiles of MSCs with different time-points are compared. Day 0 is primary human MSCs without induction was used the baseline for comparision. We used microarrays to investigate the global gene expression profiles in hBM-MSCs with ApoA-I treatment for 1, 3, 5 days during osteogenesis
2018-09-15 | GSE73087 | GEO
Project description:Eight weeks old double apolipoprotein E and apolipoprotein A-I knockout mice (DKO) were fed either normal laboratory diet (chow) or high-fat (Western) diet for 6 or 22 weeks. High-throughput sequencing technologies were used to analyse the transcriptome of the aorta of apolipoprotein E knockout (EKO, GSE163657) and DKO mice to showcase the use of the software reString (https://github.com/Stemanz/restring), a functional enrichment results aggregator.
2021-11-22 | GSE173974 | GEO
Project description:Background: High density lipoprotein (HDL) protects the artery wall by removing cholesterol from lipid-laden macrophages. However, recent evidence suggests that it might also inhibit atherogenesis by combating inflammation. Methods and Results: To identify potential anti-inflammatory mechanisms, we challenged macrophages with lipopolysaccharide (LPS), an inflammatory microbial ligand for Toll-like receptor 4 (TLR4). HDL inhibited the expression of 33% (301 of 911) of the genes normally induced by LPS, microarray analysis revealed. One of its major targets was the type I interferon response pathway, a family of potent viral immunoregulators controlled by TLR4 and the TRAM/TRIF signaling pathway. Unexpectedly, HDL’s ability to inhibit gene expression was independent of cellular cholesterol stores. Moreover, it was unaffected by downregulation of two ATP-binding cassette transporters, ABCA1 and ABCG1, that promote cholesterol efflux. To examine the pathway’s potential in vivo relevance, we used mice deficient in apolipoprotein (apo) A-I, HDL’s major protein. After infection with Salmonella (a Gram-negative bacterium that expresses LPS), apoA-I–deficient mice had 6-fold higher plasma levels of interferon-beta-a key regulator of the type I interferon response than did wild-type mice. Conclusions: HDL inhibits a subset of LPS-stimulated macrophage genes that regulate the type I interferon response, and its action is independent of sterol metabolism. These findings raise the possibility that regulation of macrophage genes by HDL might link innate immunity and cardioprotection. 12 arrays, 3 experimental groups, mMncN (no treatment), mMncL (LPS treated, exposed for 4 h to serum-free medium or serum-free medium supplemented with 100 ng/mL of LPS), and mMwtL (HDL treated, Macrophages were treated for 4 h with serum-free medium or serum-free medium supplemented with 50 mg/mL of HDL, washed twice with PBS).
2010-10-01 | E-GEOD-19340 | biostudies-arrayexpress
Project description:Protein lysine residue carbamylation is an irreversible post-translational modification, resulting in the generation of protein-bound homocitrulline (N--carbamyllysine). Carbamylation alters protein structure and can thus also alter protein function because of the loss of the charged -amino lysine moiety. Two distinct pathways can promote protein carbamylation. The first pathway occurs as a result of urea decomposition forming an equilibrium mixture of cyanate (CNO-) and the reactive electrophile isocyanate; the second (enzymatic) pathway occurs from myeloperoxidase (MPO)–catalyzed oxidation of thiocyanate (SCN-), yielding CNO- and isocyanate. We and others have previously shown that apolipoprotein A-I (apoA-I), the major protein constituent of high density lipoprotein (HDL), is a target for MPO-catalyzed modification in vivo altering its function, converting the traditionally cardio-protective lipoprotein into a pro-atherogenic and pro-apoptotic one. We hypothesized that insights into the chemical environment within the human artery wall could be gained by monitoring site-specific carbamylation patterns of apoA-I recovered from human atherosclerotic aorta. Toward testing this hypothesis, we first mapped and quantified carbamyllysine obtained from in vitro carbamylation of apoA-I by: (i) the urea driven (cyanate) vs. the inflammatory driven (MPO) pathways; as well as (ii) in lipid-poor vs. lipidated apoA-I (reconstituted nascent HDL). Our in vitro studies, interpreted in the context of existing structural models, suggest lysine residues within regional proximity of the known MPO binding sites on HDL are preferentially targeted by the enzymatic (MPO) carbamylation pathway, whereas the non-enzymatic (cyanate) pathway leads to nearly uniform distribution of carbamylated lysine residues along the apoA-I polypeptide chain. Quantitative proteomic analyses of apoA-I recovered from human aortic atheroma identified 16 of the 21 total lysine residues as carbamylated and suggests that the majority of apoA-I carbamylation in vivo occurs via the non-enzymatic cyanate pathway, and on ‘lipid-poor’ apoA-I forms. Monitoring the patterns of post translational modification of apoA-I lysine residues in vivo can provide insights into the chemical environment within human atheroma.
2022-04-06 | PXD027881 | Pride