scholarly journals ADAM17 Boosts Cholesterol Efflux and Downstream Effects of High-Density Lipoprotein on Inflammatory Pathways in Macrophages

2021 ◽  
Author(s):  
Vishal Kothari ◽  
Jingjing Tang ◽  
Yi He ◽  
Farah Kramer ◽  
Jenny E. Kanter ◽  
...  
Keyword(s):  
High Density Lipoprotein ◽  
Cholesterol Efflux ◽  
Density Lipoprotein ◽  
Myeloid Cell ◽  
Peritoneal Macrophages ◽  
High Density ◽  
Cholesterol Depletion ◽  
Proinflammatory Responses ◽  
Anti Inflammatory

Objective: HDL (high-density lipoprotein) can exert both anti-inflammatory and proinflammatory effects in macrophages due to its ability to induce cholesterol depletion. Because cholesterol depletion also increases sheddase activity of the membrane protease ADAM17 (ADAM metallopeptidase domain 17) in other cells, we examined if ADAM17 plays a role in HDL’s effects on inflammatory processes in macrophages in vitro and in vivo. Approach and Results: Sorted peritoneal macrophages from human APOA1 (apolipoprotein A1) transgenic LDL (low-density lipoprotein) receptor-deficient ( APOA1 Tg ; Ldlr −/− ) mice with and without myeloid cell-targeted ADAM17-deficiency were studied in parallel with wildtype and ADAM17-deficient bone marrow-derived macrophages stimulated with HDL in vitro. HDL increased ADAM17 expression and activity in macrophages. Furthermore, ADAM17-deficient macrophages exhibited reduced expression of ABCA1 (ATP-binding cassette A1) and reduced cholesterol efflux and were cholesterol loaded. This was caused by the absence of shedding of TNFα, a major ADAM17 substrate. Sorted thioglycollate-elicited peritoneal macrophages freshly isolated from APOA1 Tg ; Ldlr −/− mice, which have higher HDL levels than Ldlr −/− controls, showed reduced expression of interferon-inducible genes in response to lipopolysaccharide or interferon-β, but exacerbated proinflammatory responses to lipopolysaccharide for Tnfa , Cxcl1 , Ccl2 , and Il1b , phenocopying cells stimulated with HDL in vitro. These effects were all prevented in ADAM17-deficient macrophages and associated with lower concentrations of large HDL particles in APOA1 Tg ; Ldlr −/− mice with myeloid cell-targeted ADAM17-deficiency. Conclusions: The increased cholesterol loading of ADAM17-deficient macrophages prevents both anti-inflammatory and proinflammatory responses of HDL. Our findings demonstrate a novel role for ADAM17 in maintaining cholesterol efflux in macrophages, thereby regulating the immune functions of these cells.

scholarly journals Anti-Inflammatory Effects of HDL (High-Density Lipoprotein) in Macrophages Predominate Over Proinflammatory Effects in Atherosclerotic Plaques

2019 ◽  
Vol 39 (12) ◽  
Author(s):  
Panagiotis Fotakis ◽  
Vishal Kothari ◽  
David G. Thomas ◽  
Marit Westerterp ◽  
Matthew M. Molusky ◽  
...  
Keyword(s):  
Gene Expression ◽  
High Density Lipoprotein ◽  
Density Lipoprotein ◽  
High Density ◽  
Mitogen Activated Protein Kinase ◽  
Endoplasmic Reticulum Stress Response ◽  
Cholesterol Depletion ◽  
Inflammatory Gene Expression ◽  
Inflammatory Gene ◽  
Anti Inflammatory

Objective: HDL (high-density lipoprotein) infusion reduces atherosclerosis in animal models and is being evaluated as a treatment in humans. Studies have shown either anti- or proinflammatory effects of HDL in macrophages, and there is no consensus on the underlying mechanisms. Here, we interrogate the effects of HDL on inflammatory gene expression in macrophages. Approach and Results: We cultured bone marrow–derived macrophages, treated them with reconstituted HDL or HDL isolated from APOA1 Tg ;Ldlr −/− mice, and challenged them with lipopolysaccharide. Transcriptional profiling showed that HDL exerts a broad anti-inflammatory effect on lipopolysaccharide-induced genes and proinflammatory effect in a subset of genes enriched for chemokines. Cholesterol removal by POPC (1-palmitoyl-2-oleoyl-glycero-3-phosphocholine) liposomes or β-methylcyclodextrin mimicked both pro- and anti-inflammatory effects of HDL, whereas cholesterol loading by POPC/cholesterol-liposomes or acetylated LDL (low-density lipoprotein) before HDL attenuated these effects, indicating that these responses are mediated by cholesterol efflux. While early anti-inflammatory effects reflect reduced TLR (Toll-like receptor) 4 levels, late anti-inflammatory effects are due to reduced IFN (interferon) receptor signaling. Proinflammatory effects occur late and represent a modified endoplasmic reticulum stress response, mediated by IRE1a (inositol-requiring enzyme 1a)/ASK1 (apoptosis signal-regulating kinase 1)/p38 MAPK (p38 mitogen-activated protein kinase) signaling, that occurs under conditions of extreme cholesterol depletion. To investigate the effects of HDL on inflammatory gene expression in myeloid cells in atherosclerotic lesions, we injected reconstituted HDL into Apoe −/− or Ldlr −/− mice fed a Western-type diet. Reconstituted HDL infusions produced anti-inflammatory effects in lesion macrophages without any evidence of proinflammatory effects. Conclusions: Reconstituted HDL infusions in hypercholesterolemic atherosclerotic mice produced anti-inflammatory effects in lesion macrophages suggesting a beneficial therapeutic effect of HDL in vivo.

Abstract 389: Covalent Modifications of Apolipoproteins in High Density Lipoprotein by Oxidized Phospholipids Impair the Cholesterol Efflux Function of High Density Lipoprotein and are Detected in Hyperlipidemic Plasma

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Detao Gao ◽  
Lifang Zhang ◽  
Eugene Podrez
Keyword(s):  
High Density Lipoprotein ◽  
Human Plasma ◽  
Protein Function ◽  
Cholesterol Efflux ◽  
Density Lipoprotein ◽  
High Density ◽  
Oxidized Phospholipids ◽  
Protein Adduction ◽  
Covalent Modifications

Oxidized phospholipids (oxPLs) accumulate at sites of oxidative stress and contribute significantly to atherosclerosis and thrombosis. Most oxPLs have electrophilic substituents and are highly likely to form covalent adducts with proteins, thus compromising protein function. Detection of covalent interactions between oxPLs and proteins could provide important information regarding the type of proteins preferentially modified by oxPLs. However, to date, such studies are extremely limited due to significant technical challenges. We now carry out systematic studies on the protein adduction by oxPLs formed in murine and human plasma. Plasma samples were exposed to a physiologically relevant myeloperoxidase/H 2 O 2 /NO 2 – oxidizing system of phagocytes. Protein adduction by the oxPLs generated in plasma was assessed using LC-MS/MS after tryptic digestion and peptide enrichment using a novel method that we developed. We found that HDL apolipoproteins are the major targets of modification by oxPLs in both murine and human plasma. For apoA-I, the most abundant apolipoprotein in HDL, the major modification sites of oxPLs were located in the region (AA144-186), which is critical for the ABCA1 mediated cholesterol efflux to HDL. We further demonstrated that human apoA-I was also heavily crosslinked by specific oxPLs via histidine and lysine residues located in the region (AA144-186) with apoA-I, or other apolipoproteins, including apoA-II, apoA-IV and apoC-I. In vitro experiments demonstrated that oxPLs modification on lipid free apoA-I or nascent HDL (HDL3) dramatically impairs their function as cholesterol efflux mediators. Using hyperlipidemic LDLr-/- mice, we detected a crosslink adduct of apoA-II with apoE by oxPL in murine plasma. To the best of our knowledge, this is the first report for the detection of endogenous protein adducts with oxPLs.

Alteration of high-density lipoprotein functionality in Alzheimer’s disease patients

2017 ◽  
Vol 95 (8) ◽  
pp. 894-903 ◽  
Author(s):  
Paméla Camponova ◽  
Aurélie Le Page ◽  
Hicham Berrougui ◽  
Julie Lamoureux ◽  
Graham Pawelec ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
High Density Lipoprotein ◽  
Healthy Subjects ◽  
Cholesterol Efflux ◽  
Density Lipoprotein ◽  
High Density ◽  
Elderly Subjects ◽  
The Difference

The aims of the present study were to determine whether high-density lipoprotein (HDL) functionality-mediated cholesterol efflux is altered in Alzheimer’s disease and to investigate the role and effect of amyloid-beta (Aβ) in the regulation of the anti-atherogenic activity of HDL. Eighty-seven elderly subjects were recruited, of whom 27 were healthy, 27 had mild cognitive impairment (MCI), and 33 had mild Alzheimer’s disease (mAD). Our results showed that total cholesterol levels are negatively correlated with the Mini-Mental State Examination (MMSE) score (r = –0.2602, p = 0.0182). HDL from the mAD patients was less efficient at mediating cholesterol efflux from J774 macrophages (p < 0.05) than HDL from the healthy subjects and MCI patients. While HDL from the MCI patients was also less efficient at mediating cholesterol efflux than HDL from the healthy subjects, the difference was not significant. Interestingly, the difference between the healthy subjects and the MCI and mAD patients with respect to the capacity of HDL to mediate cholesterol efflux disappeared when ATP-binding cassette transporter A1 (ABCA1)-enriched J774 macrophages were used. HDL fluidity was significantly inversely correlated with the MMSE scores (r = –0.4137, p < 0.009). In vitro measurements of cholesterol efflux using J774 macrophages showed that neither Aβ1-40nor Aβ1-42stimulate cholesterol efflux from unenriched J774 macrophages in basal or ABCA1-enriched J774 macrophages.

scholarly journals High-density lipoprotein 3 physicochemical modifications induced by interaction with human polymorphonuclear leucocytes affect their ability to remove cholesterol from cells

1996 ◽  
Vol 314 (1) ◽  
pp. 285-292 ◽  
Author(s):  
Anne COGNY ◽  
Véronique ATGER ◽  
Jean-Louis PAUL ◽  
Théophile SONI ◽  
Nicole MOATTI
Keyword(s):  
High Density Lipoprotein ◽  
Cholesterol Efflux ◽  
Density Lipoprotein ◽  
High Density ◽  
Molar Ratio ◽  
Polymorphonuclear Leucocytes ◽  
Partial Loss ◽  
Apo Ai

1. We have recently reported that a short incubation (60 min) in vitro of high-density lipoprotein (HDL) 3 with human polymorphonuclear leucocytes (PMNs) leads to a proteolytic cleavage of apolipoprotein (apo) AII and to a change in the distribution of apo AI isoforms [Cogny, Paul, Atger, Soni and Moatti (1994) Eur. J. Biochem. 222, 965–973]. Since PMNs have been observed to be present in the earliest atherosclerotic lesions for a number of days, we investigated the HDL3 physicochemical modifications induced by in vitro interaction for a long period of time (24 h) with PMNs and the consequences of the changes on the ability of HDL3 to remove cholesterol from cells. 2. The stimulated PMN modification of HDL3 over 24 h resulted in a partial loss of protein with no variation in lipid molar ratio and a loss of 50% of HDL α-tocopherol content. The decrease in total protein was due first to a complete degradation of apo AII, and secondly to a partial loss of apo AI. The apo AI remaining on the particles was in part hydrolysed and the apo AI-1 isoform was completely shifted to the apo AI-2 isoform. These apo changes were accompanied by a displacement of the native HDL3 apparent size toward predominantly larger particles. 3. The ability of PMN-modified HDL3 to remove 3H-labelled free cholesterol from cells was measured in two cell lines: Fu5AH rat hepatoma cells and J774 mouse macrophages. HDL3 which had only a limited contact with PMNs (60 min) showed only a small non-significant reduction in the efficiency of cholesterol efflux. On the other hand, compared with native HDL3, HDL3 modified by PMNs for 24 h had a markedly reduced ability to remove cholesterol from cells, regardless of the type of cell. 4. The results suggest that PMN-modified HDL3, if occurring in vivo, could contribute to acceleration of the atherogenic process by decreasing the cholesterol efflux from cells.

Abstract 14785: Oral Administration of Eicosapentaenoic Acid Ameliorates Anti-inflammatory Functions of High-Density Lipoprotein in Dyslipidemic Patients

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Nobuaki Tanaka ◽  
Tatsuro Ishida ◽  
Manabu Nagao ◽  
Takeshige Mori ◽  
Tomoko Monguchi ◽  
...  
Keyword(s):  
Oral Administration ◽  
Eicosapentaenoic Acid ◽  
High Density Lipoprotein ◽  
Cholesterol Efflux ◽  
Density Lipoprotein ◽  
High Density ◽  
Endothelial Cell Migration ◽  
High Dose ◽  
Cholesterol Efflux Capacity ◽  
Anti Inflammatory

Objective: Previous studies have reported that inflammation converts high-density lipoprotein (HDL) to dysfunctional form lacking its anti-inflammatory properties. However, little is known about pharmacological therapy to improve HDL function. It has been recently postulated that fatty acid component in HDL-phospholipids modulates HDL functions. We investigated the effect of oral administration of high dose eicosapentaenoic acid (EPA) on HDL functions. Methods: Patients with dyslipidemia were treated with 1800 mg/day EPA for 4 weeks, and HDL fractions were isolated by ultracentrifuge before and after the EPA treatment. HDL functions were evaluated by multiple in vitro cell-based assays. Results: The EPA treatment did not affect the quantity in the serum lipid profile including serum cholesterol, triglyceride and apolipoprotein levels, but significantly increased EPA concentrations both in the serum and HDL fraction. The EPA/arachidonic acid ratio in the HDL was in proportion to that in the serum, suggesting that EPA was incorporated in HDL particles. The HDL after EPA treatment possessed high activity of paraoxonase-1, an HDL-associated anti-oxidative enzyme, compared to HDL before EPA treatment. In addition, the EPA-rich HDL significantly improved endothelial cell migration, and markedly inhibited cytokine-induced expression of vascular cell adhesion molecule-1 in human umbilical vein endothelial cells, compared to HDL before the EPA treatment. Moreover, the EPA-rich HDL had high capacity of cholesterol efflux capacity from macrophages. Conclusion: Administration of high dose EPA improves anti-inflammatory, anti-oxidative, and cholesterol efflux capacity of HDL in dyslipidemic patients. Thus, EPA may transform “dysfunctional HDL” to “functional”, in patients with coronary risk factors.

scholarly journals Nascent HDL (High-Density Lipoprotein) Discs Carry Cholesterol to HDL Spheres

2020 ◽  
Vol 40 (5) ◽  
pp. 1182-1194 ◽  
Author(s):  
Alexei V. Navdaev ◽  
Lorenzo Sborgi ◽  
Samuel D. Wright ◽  
Svetlana A. Didichenko
Keyword(s):  
High Density Lipoprotein ◽  
Cholesterol Efflux ◽  
Density Lipoprotein ◽  
Fluorescent Labeling ◽  
High Density ◽  
Atp Binding Cassette Transporter ◽  
Spherical Plasma ◽  
Apo Ai

Objective: To characterize the fate of protein and lipid in nascent HDL (high-density lipoprotein) in plasma and explore the role of interaction between nascent HDL and mature HDL in promoting ABCA1 (ATP-binding cassette transporter 1)-dependent cholesterol efflux. Approach and Results: Two discoidal species, nascent HDL produced by RAW264.7 cells expressing ABCA1 (LpA-I [apo AI containing particles formed by incubating ABCA1-expressing cells with apo AI]), and CSL112, human apo AI (apolipoprotein AI) reconstituted with phospholipids, were used for in vitro incubations with human plasma or purified spherical plasma HDL. Fluorescent labeling and biotinylation of HDL were employed to follow the redistribution of cholesterol and apo AI, cholesterol efflux was measured using cholesterol-loaded cells. We show that both nascent LpA-I and CSL112 can rapidly fuse with spherical HDL. Redistribution of the apo AI molecules and cholesterol after particle fusion leads to the formation of (1) enlarged, remodeled, lipid-rich HDL particles carrying lipid and apo AI from LpA-I and (2) lipid-poor apo AI particles carrying apo AI from both discs and spheres. The interaction of discs and spheres led to a greater than additive elevation of ABCA1-dependent cholesterol efflux. Conclusions: These data demonstrate that although newly formed discs are relatively poor substrates for ABCA1, they can interact with spheres to produce lipid-poor apo AI, a much better substrate for ABCA1. Because the lipid-poor apo AI generated in this interaction can itself become discoid by the action of ABCA1, cycles of cholesterol efflux and disc-sphere fusion may result in net ABCA1-dependent transfer of cholesterol from cells to HDL spheres. This process may be of particular importance in atherosclerotic plaque where cholesterol acceptors may be limiting.

scholarly journals Site-specific 5-hydroxytryptophan incorporation into apolipoprotein A-I impairs cholesterol efflux activity and high-density lipoprotein biogenesis

2020 ◽  
Vol 295 (15) ◽  
pp. 4836-4848 ◽  
Author(s):  
Maryam Zamanian-Daryoush ◽  
Valentin Gogonea ◽  
Anthony J. DiDonato ◽  
Jennifer A. Buffa ◽  
Ibrahim Choucair ◽  
...  
Keyword(s):  
High Density Lipoprotein ◽  
Cholesterol Efflux ◽  
Density Lipoprotein ◽  
Trna Synthetase ◽  
High Density ◽  
Oxidative Modification ◽  
Paraoxonase 1 ◽  
Site Specific ◽  
Apolipoprotein A

Apolipoprotein A-I (apoA-I) is the major protein constituent of high-density lipoprotein (HDL) and a target of myeloperoxidase-dependent oxidation in the artery wall. In atherosclerotic lesions, apoA-I exhibits marked oxidative modifications at multiple sites, including Trp72. Site-specific mutagenesis studies have suggested, but have not conclusively shown, that oxidative modification of Trp72 of apoA-I impairs many atheroprotective properties of this lipoprotein. Herein, we used genetic code expansion technology with an engineered Saccharomyces cerevisiae tryptophanyl tRNA-synthetase (Trp-RS):suppressor tRNA pair to insert the noncanonical amino acid 5-hydroxytryptophan (5-OHTrp) at position 72 in recombinant human apoA-I and confirmed site-specific incorporation utilizing MS. In functional characterization studies, 5-OHTrp72 apoA-I (compared with WT apoA-I) exhibited reduced ABC subfamily A member 1 (ABCA1)-dependent cholesterol acceptor activity in vitro (41.73 ± 6.57% inhibition; p < 0.01). Additionally, 5-OHTrp72 apoA-I displayed increased activation and stabilization of paraoxonase 1 (PON1) activity (μmol/min/mg) when compared with WT apoA-I and comparable PON1 activation/stabilization compared with reconstituted HDL (WT apoA-I, 1.92 ± 0.04; 5-OHTrp72 apoA-I, 2.35 ± 0.0; and HDL, 2.33 ± 0.1; p < 0.001, p < 0.001, and p < 0.001, respectively). Following injection into apoA-I–deficient mice, 5-OHTrp72 apoA-I reached plasma levels comparable with those of native apoA-I yet exhibited significantly reduced (48%; p < 0.01) lipidation and evidence of HDL biogenesis. Collectively, these findings unequivocally reveal that site-specific oxidative modification of apoA-I via 5-OHTrp at Trp72 impairs cholesterol efflux and the rate-limiting step of HDL biogenesis both in vitro and in vivo.

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