ABCG subfamily of human ATP-binding cassette proteins

2002 ◽  
Vol 74 (11) ◽  
pp. 2057-2081 ◽  
Author(s):  
Stefan Lorkowski ◽  
Paul Cullen
Keyword(s):  
Abc Transporters ◽  
Foam Cell ◽  
Current Knowledge ◽  
Cell Formation ◽  
Evolutionary Relationship ◽  
The Body ◽  
High Density Lipoproteins ◽  
Foam Cell Formation ◽  
Atp Binding ◽  
Atp Binding Cassette

ATP-binding cassette (ABC) proteins form one of the largest known protein families and have been found in all known organisms. Most members of the human ABC protein family are membrane-spanning transporters that use energy derived from the hydrolysis of ATP to transport specific substrates across cell membranes. Mutations in certain human ABC transporters of the subfamilies A, B, C, and D have been shown to cause a wide variety of inherited diseases such as the lung condition cystic fibrosis, the nervous degenerative condition adrenoleukodystrophy (of Lorenzo’s Oil fame), hereditary macular degeneration of the eye (Stargardt’s disease), and inherited deficiency of circulating high-density lipoproteins (Tangier disease or familial hypoalphalipoproteinemia). Very recent studies showed that mutations in two members of the subfamily G of human ABC transporters (ABCG5 and ABCG8) cause a condition called sitosterolemia in which plant sterols accumulate in the body and may be responsible for influencing total body sterol homeostasis. In addition, other members of the subfamily G, namely ABCG1 and ABCG4, have also been shown to be involved in cellular lipid trafficking and are thought to play important roles during foam cell formation of human macrophages. By contrast, ABCG2 is a multidrug resistance transporter.In this review, we focus on the current knowledge and physiological background of the members of the subfamily G. We also present new insights on the evolutionary relationship of human and nonhuman ABCG proteins.

Abstract 276: Shockwave Reduces Macrophage Foam Cell Formation Via Increased Expression of ATP Binding Cassette Transporters.

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Wonkyoung Cho ◽  
Young Eun Yoon ◽  
Kihwan Kwon ◽  
Young Mi Park
Keyword(s):  
Western Blot ◽  
Foam Cell ◽  
Cell Formation ◽  
Foam Cell Formation ◽  
Atp Binding ◽  
Mrna Levels ◽  
Macrophage Foam Cell ◽  
Migration Assay ◽  
Intracellular Cholesterol ◽  
Atp Binding Cassette

Background: Excessive lipid accumulation by macrophages plays a crucial role in atherosclerosis. Foam cells are generated by uncontrolled uptake of modified LDL, especially oxidized LDL (oxLDL), and/or impaired cholesterol efflux mediated by ATP-binding cassette (ABC) family transporters, ABCA-1 and ABCG-1. Shockwave, elicited by transient pressure disturbance, have been used for extracorporeal lithotripsy or for treating musculoskeletal disorders. Our current study suggests an evidence that shockwave may have anti-atherogenic effect by inhibiting foam cell formation. Methods/Results: Murine peritoneal macrophages were exposed to shockwaves at 0.04 mJ/mm 2 with 1000 impulses, lysed after 6, 18 and 24 hours, and tested for expression of ABCA-1 and ABCG-1. The western blot showed that shockwave induced 2.0-2.8 fold increase of ABCA-1 and ABCG-1 within 18-24 hours. mRNA levels of ABCA-1 and ABCG-1 were also increased by shockwave with 2.0 fold of peak increase in 18 hours. The increased expression of ABCA-1 and ABCG-1 was mediated by phosphorylation of ERK 1/2 (Tyr204). Western blot analysis revealed that shockwave induced phosphorylation of ERK 1/2 (Tyr204) in murine macrophages. Shockwave-induced increase of ABCA-1 and ABCG-1 was blocked by U0126 (40µM), a specific inhibitor for ERK. Oil-red O staining showed that macrophages exposed to shockwave had 25% less intracellular lipid droplets. Intracellular cholesterol measured by cholesterol oxidase and esterase revealed that macrophages exposed to shockwave had 23% less intracellular cholesterol when incubated with oxLDL (50µg/ml) for 16 hours. In vitro migration assays including modified Boyden chamber migration assay and scratch wound healing migration assay showed that macrophages exposed to shockwave had 1.2 fold more migration and had diminished migration-inhibitory effect of oxLDL. Conclusions: Shockwave reduces macrophage foam cell formation via ERK-mediated increase of ABCA-1 and ABCG-1 mediating lipid efflux and promotes macrophage migration which may induce macrophage egress from atherosclerotic lesion. Our study suggests anti-atherogenic effects of shockwave as a potential treatment modality for atherosclerosis.

scholarly journals Human ATP-Binding Cassette Transporter TaqMan Low-Density Array: Analysis of Macrophage Differentiation and Foam Cell Formation

2006 ◽  
Vol 52 (2) ◽  
pp. 310-313 ◽  
Author(s):  
Thomas Langmann ◽  
Richard Mauerer ◽  
Gerd Schmitz
Keyword(s):  
Multidrug Resistance ◽  
Abc Transporter ◽  
Abc Transporters ◽  
Metabolic Regulation ◽  
Foam Cell ◽  
Expression Patterns ◽  
Foam Cell Formation ◽  
Atp Binding ◽  
Low Density ◽  
Atp Binding Cassette

Abstract Background: ATP-binding cassette (ABC) transporters cause various diseases and regulate many physiologic processes, such as lipid homeostasis, iron transport, and immune mechanisms. Several ABC transporters are involved in bile acid, phospholipid, and sterol transport, and their expression is itself controlled by lipids. In addition, ABC proteins mediate drug export in tumor cells and promote the development of multidrug resistance. Methods: We created an ABC Transporter TaqMan Low-Density Array based on an Applied Biosystems 7900HT Micro Fluidic Card. We used a 2-μL reaction well with 2 ng of sample. To evaluate this method for lipidomic research and to characterize expression patterns of ABC transporters in cells relevant for atherosclerosis research, we monitored mRNA expression in human primary monocytes, in vitro–differentiated macrophages, and cells stimulated with the liver-X-receptor and retinoid-X-receptor agonists T0901317 and 9-cis retinoic acid, mimicking sterol loading. Results: The method enabled simultaneous analysis of 47 human ABC transporters and the reference gene 18S rRNA in 2 replicates of 4 samples per run. Conclusions: The new system uses only 2 ng of sample and small volumes of reagent, and the precaptured primers and probes avoided labor-intensive pipetting steps. The ABC Transporter TaqMan Low-Density Array may be a useful tool to monitor dysregulated ABC transporter mRNA profiles in human lipid disorders and cancer-related multidrug resistance and to analyze the pharmacologic and metabolic regulation of ABC transporter expression important for drug development in large-scale screening approaches.

scholarly journals Perivascular Adipose-Derived Exosomes Reduce Foam Cell Formation by Regulating Expression of Cholesterol Transporters

2021 ◽  
Vol 8 ◽  
Author(s):  
Yan Liu ◽  
Yan Sun ◽  
Xuze Lin ◽  
Dai Zhang ◽  
Chengping Hu ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Lipid Accumulation ◽  
Foam Cell ◽  
Cell Formation ◽  
Density Lipoprotein ◽  
Foam Cell Formation ◽  
Atp Binding ◽  
Macrophage Foam Cell ◽  
Atp Binding Cassette Transporter ◽  
Atp Binding Cassette

Background: Accumulating evidence demonstrates that perivascular adipose tissue (PVAT) plays an important role in maintaining vascular homeostasis. The formation of macrophage foam cells is a central feature of atherosclerosis. This study aimed to evaluate the effect of PVAT-derived exosomes (EXOs) on the lipid accumulation of macrophages and verify the anti-atherogenic characteristics of PVAT.Methods and Results: We extracted EXOs from the PVAT and subcutaneous adipose tissue (SCAT) of wild-type C57BL/6J mice. After coincubation, the EXOs were taken up by RAW264.7 cells. Oil Red O staining revealed that macrophage foam cell formation and intracellular lipid accumulation were ameliorated by PVAT-EXOs. Flow cytometry showed that PVAT-EXOs significantly reduced macrophage uptake of fluorescence-labelled oxidised low-density lipoprotein (ox-LDL). In addition, high-density lipoprotein-induced cholesterol efflux was promoted by PVAT-EXOs. Western blot analysis showed the downregulation of macrophage scavenger receptor A and the upregulation of ATP-binding cassette transporter A1 and ATP-binding cassette transporter G1, which could be mediated by the overexpression of peroxisome proliferator-activated receptor γ and was independent of liver X receptor α.Conclusion: Our findings suggest that PVAT-EXOs reduce macrophage foam cell formation by regulating the expression of cholesterol transport proteins, which provides a novel mechanism by which PVAT protects the vasculature from atherosclerosis.

scholarly journals Human ATP–Binding Cassette G1 Controls Macrophage Lipoprotein Lipase Bioavailability and Promotes Foam Cell Formation

2012 ◽  
Vol 32 (9) ◽  
pp. 2223-2231 ◽  
Author(s):  
Maryline Olivier ◽  
Michael W. Tanck ◽  
Ruud Out ◽  
Elise F. Villard ◽  
Bart Lammers ◽  
...  
Keyword(s):  
Lipoprotein Lipase ◽  
Foam Cell ◽  
Cell Formation ◽  
Foam Cell Formation ◽  
Atp Binding ◽  
Atp Binding Cassette

scholarly journals Ablation of Galectin-12 Inhibits Atherosclerosis through Enhancement of M2 Macrophage Polarization

2020 ◽  
Vol 21 (15) ◽  
pp. 5511
Author(s):  
En-Shyh Lin ◽  
Yu-An Hsu ◽  
Ching-Yao Chang ◽  
Hui-Ju Lin ◽  
Chih Sheng Chen ◽  
...  
Keyword(s):  
Foam Cell ◽  
Macrophage Polarization ◽  
Cell Formation ◽  
Foam Cell Formation ◽  
Atp Binding ◽  
M2 Macrophage ◽  
Murine Macrophages ◽  
M2 Macrophage Polarization ◽  
Atp Binding Cassette

The formation of foam cells, which are macrophages that have engulfed oxidized low-density lipoprotein (OxLDL), constitutes the first stage in the development of atherosclerosis. Previously, we found that knocking down galectin-12, a negative regulator of lipolysis, leads to reduced secretion of monocyte chemoattractant protein-1 (MCP-1), a chemokine that plays an important role in atherosclerosis. This prompted us to study the role of galectin-12 in atherosclerosis. With that aim, we examined foam cell formation in Gal12‒/‒ murine macrophages exposed to OxLDL and acetylated LDL (AcLDL). Then, we generated an LDL receptor and galectin-12 double knockout (DKO) mice and studied the effect of galectin-12 on macrophage function and atherosclerosis. Lastly, we evaluated the role of galectin-12 in human THP-1 macrophages using a doxycycline-inducible conditional knockdown system. Galectin-12 knockout significantly inhibited foam cell formation in murine macrophages through the downregulation of cluster of differentiation 36 (CD36), and the upregulation of ATP Binding Cassette Subfamily A Member 1 (ABCA1), ATP Binding Cassette Subfamily G Member 1 (ABCG1), and scavenger receptor class B type 1 (SRB1). Consistent with this, galectin-12 knockdown inhibited foam cell formation in human macrophages. In addition, the ablation of galectin-12 promoted M2 macrophage polarization in human and murine macrophages as evidenced by the upregulation of the M2 marker genes, CD206 and CD163, and downregulation of the M1 cytokines, tumor necrosis factor α (TNF- α), interleukin-6 (IL-6), and MCP-1. Moreover, the ablation of galectin-12 decreased atherosclerosis formation in DKO mice. Based on these results, we propose galectin-12 as a potential therapeutic target for atherosclerosis.

Abstract 450: Modification of HDL by Reactive Aldehydes Impairs HDL's Athero-protective Functions

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Rebecca L Holme ◽  
Alexandra C Chadwick ◽  
Sarah C Proudfoot ◽  
Yiliang Chen ◽  
Devi Prasadh Ramakrishnan ◽  
...  
Keyword(s):  
Foam Cell ◽  
Cell Formation ◽  
Oxidative Modification ◽  
High Density Lipoproteins ◽  
Foam Cell Formation ◽  
Macrophage Migration ◽  
Mrna Levels ◽  
Protective Effects ◽  
Impaired Ability ◽  
Reactive Aldehydes

High density lipoproteins (HDL) are athero-protective particles that promote the removal of excess cholesterol from lipid-loaded macrophages and stimulate their migration in order to protect against foam cell formation, a precursor to atherosclerotic plaque build-up. Recently, studies have shown that oxidative modification of HDL prevents HDL from protecting against atherosclerosis; however, the exact mechanisms by which this occurs are not well defined. We hypothesize that oxidative modification of HDL by reactive aldehydes such as acrolein (a major component of cigarette smoke) and 4-hydroxynonenal (HNE; a product of lipid peroxidation) impairs HDL’s athero-protective effects in macrophages. We tested our hypothesis using three different assays. First, we determined that modified forms of HDL upregulate mRNA levels of pro-atherogenic scavenger receptors such as cluster of differentiation 36 (CD36), a known oxidized LDL receptor. Incubation of macrophages with native HDL did not exert similar effects. Second, we tested the ability of oxidized HDL to prevent foam cell formation. Peritoneal macrophages isolated from WT C57Bl/J mice were cholesterol-loaded and incubated with native HDL, acrolein-modified HDL (acro-HDL), or HNE-modified HDL (HNE-HDL). Oil Red-O staining demonstrated that 24% of macrophages had foam cell formation upon incubation with native HDL, whereas 61% and 49% foam cell formation was observed for acro- and HNE-HDL, respectively. Preliminary data suggests this may be CD36-dependent. Finally, using a Boyden chamber assay, we demonstrated that both acro- and HNE-HDL, but not native HDL, had an impaired ability to promote macrophage migration (43% and 72% of HDL cell migration levels, respectively). We determined that the inability of acro- and/or HNE-HDL to stimulate macrophage migration may be due to an impaired ability of these modified lipoproteins to activate the PI3K pathway, as shown by decreased levels of phosphorylated protein kinase B (Akt). In conclusion, we have identified three independent mechanisms by which modification of HDL with acrolein or HNE impairs HDL’s cardio-protective effects and, instead, generates a particle that promotes pathways that lead to atherosclerosis.

scholarly journals Chronic stress: a critical risk factor for atherosclerosis

2019 ◽  
Vol 47 (4) ◽  
pp. 1429-1440 ◽  
Author(s):  
Bo-chen Yao ◽  
Ling-bing Meng ◽  
Meng-lei Hao ◽  
Yuan-meng Zhang ◽  
Tao Gong ◽  
...  
Keyword(s):  
Risk Factor ◽  
Chronic Stress ◽  
Vascular System ◽  
Foam Cell ◽  
Cell Formation ◽  
Systemic Reaction ◽  
Epidemiological Studies ◽  
The Body ◽  
Foam Cell Formation ◽  
Signal Pathways

Chronic stress refers to the non-specific systemic reaction that occurs when the body is stimulated by various internal and external negative factors over a long time. The physiological response to chronic stress exposure has long been recognized as a potent modulator in the occurrence of atherosclerosis. Furthermore, research has confirmed the correlation between atherosclerosis and cardiovascular events. Chronic stress is pervasive during negative life events and may lead to the formation of plaque. Several epidemiological studies have shown that chronic stress is an independent risk factor for the development of vascular disease and for increased morbidity and mortality in patients with pre-existing coronary artery disease. One possible mechanism for this process is that chronic stress causes endothelial injury, directly activating macrophages, promoting foam cell formation and generating the formation of atherosclerotic plaque. This mechanism involves numerous variables, including inflammation, signal pathways, lipid metabolism and endothelial function. The mechanism of chronic stress in atherosclerosis should be further investigated to provide a theoretical basis for efforts to eliminate the effect of chronic stress on the cardiocerebral vascular system.

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