Human ABCA1 BAC Transgenic Mice Show Increased High Density Lipoprotein Cholesterol and ApoAI-dependent Efflux Stimulated by an Internal Promoter Containing Liver X Receptor Response Elements in Intron 1

Singaraja, Roshni R.; Bocher, Virginie; James, E.; Clee, Susanne M.; Zhang, Linhua; Leavitt, Blair R.; Teng, Bing; Brooks‐Wilson, Angela; Kwok, Anita; Bissada, Nagat; Yang, Yuzhou; Liu, Guoqing; Tafuri, Sherrie R.; Fiévet, Catherine; Wellington, Cheryl L.; Staels, Bart; Hayden, Michael R.

doi:10.1074/jbc.m102503200

Cited by 180 publications

(169 citation statements)

References 48 publications

Supporting

Mentioning

152

Contrasting

Unclassified

Order By: Relevance

“…On the other hand, in vitro overexpression of functional ABCA1 in the cells (10,11) and induction of ABCA1 expression by cyclic AMP analogues (12,13) or by the ligands for the liver X receptor or retinoid X receptor (14,15) enhanced the release of cellular cholesterol and phospholipid by apolipoprotein. The transgenic mice for ABCA1 had a significant increase in plasma HDL (16,17). These results indicate that this protein is a regulating factor for the plasma HDL level through generation of HDL by the apolipoproteincell interaction.…”

mentioning

confidence: 60%

Probucol Inactivates ABCA1 in the Plasma Membrane with Respect to Its Mediation of Apolipoprotein Binding and High Density Lipoprotein Assembly and to Its Proteolytic Degradation

Chengai

Tsujita

Hayashi

et al. 2004

Journal of Biological Chemistry

View full text Add to dashboard Cite

Probucol has been shown to inhibit the release of cellular lipid by helical apolipoprotein and thereby to reduce plasma high density lipoprotein. We attempted to explore the underlying mechanism for this effect in human fibroblast WI-38. Probucol inhibited the apoA-Imediated cellular lipid release and binding of apoA-I to the cells in a dose-dependent manner. It did not influence cellular uptake of low density lipoprotein, transport of cholesterol to the cell surface whether de novo synthesized or delivered as low density lipoprotein, and overall cellular content of cholesterol, although biosynthesis of lipids from acetate was somewhat increased. Probucol did not affect the mRNA level of ABCA1, and ABCA1 was recovered along with marker proteins for plasma membrane regardless of the presence of probucol. However, the protein level of ABCA1 increased, and the rate of its decay in the presence of cycloheximide was slower in the probucol-treated cells. ABCA1 in the probucol-treated cells was resistant to digestion by calpain but not by trypsin. We concluded that probucol inactivates ABCA1 in the plasma membrane with respect to its function in mediating binding of and lipid release by apolipoprotein and with respect to proteolytic degradation by calpain.Cholesterol is an essential molecule for animal cells to maintain and regulate function and structure of the biomembrane. It is synthesized in most somatic cells, whereas its catabolic site is limited to the liver and to the steroidogenic cells except for partial hydroxylation in some somatic cells. Accordingly, cholesterol is removed from the cells and transported to the liver for its conversion to bile acids, and this is one of the essential events in cholesterol homeostasis for the body and for the cells (1). High density lipoprotein (HDL) 1 is believed to play a central role in this system, and this is thought to be one of the antiatherogenic characteristics of HDL. This reaction takes place through at least two distinct mechanisms: 1) physicochemical release of cholesterol from the cell surface, which is driven by cholesterol esterification on HDL, and 2) the apolipoprotein-mediated pathway to remove cellular cholesterol and phospholipid to generate new HDL particles (2). HDL thus plays a central role in both mechanisms.Apolipoprotein-dependent cellular cholesterol release is absent in fibroblasts from patients with Tangier disease (3, 4), and mutations in the gene encoding the ATP-binding cassette transporter A1 (ABCA1) are the underlying cause of this disease (5-9). On the other hand, in vitro overexpression of functional ABCA1 in the cells (10, 11) and induction of ABCA1 expression by cyclic AMP analogues (12, 13) or by the ligands for the liver X receptor or retinoid X receptor (14, 15) enhanced the release of cellular cholesterol and phospholipid by apolipoprotein. The transgenic mice for ABCA1 had a significant increase in plasma HDL (16,17). These results indicate that this protein is a regulating factor for the plasma HDL level through generation of HDL b...

show abstract

mentioning

confidence: 60%

Probucol Inactivates ABCA1 in the Plasma Membrane with Respect to Its Mediation of Apolipoprotein Binding and High Density Lipoprotein Assembly and to Its Proteolytic Degradation

Chengai

Tsujita

Hayashi

et al. 2004

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…In animal models, genetic deletion of ABCA1 results in the pathophysiologic conditions similar to those found in Tangier disease patients, such as reduced plasma cholesterol levels, which is mainly due to decreased HDL levels and the accumulation of lipid-laden macrophage/foam cells (34). In contrast, overexpression of ABCA1 leads to increased macrophage free cholesterol efflux, improved plasma lipid profiles, and reduced lesions in proatherogenic mice (6,17,35,36). Interestingly, alteration of ABCA1 expression tissue specifically leads to different observations: 1) either overexpression or inactivation of hepatic ABCA1 can lead to the development of atherosclerosis (37,38) and 2) activation of macrophage ABCA1 can inhibit atherosclerosis, whereas inactivation of macrophage ABCA1 can increase atherosclerosis (18,37,39).…”

Section: Discussionmentioning

confidence: 99%

Inhibition of ERK1/2 and Activation of Liver X Receptor Synergistically Induce Macrophage ABCA1 Expression and Cholesterol Efflux

Zhou

Yin

Guo

et al. 2010

Journal of Biological Chemistry

View full text Add to dashboard Cite

ATP-binding cassette transporter A1 (ABCA1), a molecule mediating free cholesterol efflux from peripheral tissues to apoAI and high density lipoprotein (HDL), inhibits the formation of lipid-laden macrophage/foam cells and the development of atherosclerosis. ERK1/2 are important signaling molecules regulating cellular growth and differentiation. The ERK1/2 signaling pathway is implicated in cardiac development and hypertrophy. However, the role of ERK1/2 in the development of atherosclerosis, particularly in macrophage cholesterol homeostasis, is unknown. In this study, we investigated the effects of ERK1/2 activity on macrophage ABCA1 expression and cholesterol efflux. Compared with a minor effect by inhibition of other kinases, inhibition of ERK1/2 significantly increased macrophage cholesterol efflux to apoAI and HDL. In contrast, activation of ERK1/2 reduced macrophage cholesterol efflux and ABCA1 expression. The increased cholesterol efflux by ERK1/2 inhibitors was associated with the increased ABCA1 levels and the binding of apoAI to cells. The increased ABCA1 by ERK1/2 inhibitors was due to increased ABCA1 mRNA and protein stability. The induction of ABCA1 expression and cholesterol efflux by ERK1/2 inhibitors was concentration-dependent. The mechanism study indicated that activation of liver X receptor (LXR) had little effect on ERK1/2 expression and activation. ERK1/2 inhibitors had no effect on macrophage LXR␣/␤ expression, whereas they did not influence the activation or the inhibition of the ABCA1 promoter by LXR or sterol regulatory element-binding protein (SREBP). However, inhibition of ERK1/2 and activation of LXR synergistically induced macrophage cholesterol efflux and ABCA1 expression. Our data suggest that ERK1/2 activity can play an important role in macrophage cholesterol trafficking.Development of atherosclerotic lesions in coronary arteries is an underlying cause of coronary heart disease. Lipid-laden macrophage/foam cells are a prominent part of atherosclerotic lesions (1). Cellular cholesterol content in macrophages is determined by uptake and efflux of cholesterol (2). The type A scavenger receptor and type B scavenger receptor (CD36) mediate the binding and internalization of modified low density lipoprotein (LDL), 3 thus, demonstrating pro-atherogenic properties (3, 4). In contrast, type BI scavenger receptor and ATPbinding cassette transporter A1 (ABCA1) can mediate cellular free cholesterol efflux to extracellular high density lipoprotein (HDL) or lipid-free apolipoprotein AI (apoAI) thereby inhibiting the development of atherosclerosis (5, 6). Compared with bi-directional cholesterol transport across cellular membranes that are mediated by type BI scavenger receptor (7, 8), ABCA1 stimulates free cholesterol efflux from macrophages and other peripheral cell types to apoAI and/or HDL by using the energy from ATP hydrolysis (9). The binding of free cholesterol and phospholipids to apoAI also leads to the generation of nascent HDL (10). ABCA1 can also mediate cholesterol efflux to exog...

show abstract

“…Additional experiments to find new physiological targets of miR-33 are needed to confirm this hypothesis. Finally, because hepatic ABCA1 is critical to the generation of plasma HDL (34,35), it seems likely that a combination therapy that includes statins and miR-33 antagomirs might result in both decreased LDL levels and increased HDL levels, thus improving the prognosis for patients with hypercholesterolemia and cardiovascular disease.…”

Section: Discussionmentioning

confidence: 99%

miR-33 links SREBP-2 induction to repression of sterol transporters

Marquart

Allen

Ory

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

505

501

View full text Add to dashboard Cite

The sterol regulatory element binding protein 2 (SREBP-2) and the liver X receptor (LXR) control antagonistic transcriptional programs that stimulate cellular cholesterol uptake and synthesis, and cholesterol efflux, respectively. The clinical importance of SREBP-2 is revealed in patients with hypercholesterolemia treated with statins, which reduce low-density lipoprotein (LDL) cholesterol levels by increasing hepatic expression of SREBP-2 and its target, the LDL receptor. Here we show that miR-33 is encoded within SREBP-2 and that both mRNAs are coexpressed. We also identify sequences in the 3′ UTR of ABCA1 and ABCG1, sterol transporter genes both previously shown to be regulated by LXR, as targets for miR-33-mediated silencing. Our data show that LXR-dependent cholesterol efflux to both ApoAI and serum is ameliorated by miR-33 overexpression and, conversely, stimulated by miR-33 silencing. Finally, we show that ABCA1 mRNA and protein and plasma HDL levels decline after hepatic overexpression of miR-33, whereas they increase after hepatic miR-33 silencing. These results suggest novel ways to manage hypercholesterolemic patients.

show abstract

Human ABCA1 BAC Transgenic Mice Show Increased High Density Lipoprotein Cholesterol and ApoAI-dependent Efflux Stimulated by an Internal Promoter Containing Liver X Receptor Response Elements in Intron 1

Cited by 180 publications

References 48 publications

Probucol Inactivates ABCA1 in the Plasma Membrane with Respect to Its Mediation of Apolipoprotein Binding and High Density Lipoprotein Assembly and to Its Proteolytic Degradation

Probucol Inactivates ABCA1 in the Plasma Membrane with Respect to Its Mediation of Apolipoprotein Binding and High Density Lipoprotein Assembly and to Its Proteolytic Degradation

Inhibition of ERK1/2 and Activation of Liver X Receptor Synergistically Induce Macrophage ABCA1 Expression and Cholesterol Efflux

miR-33 links SREBP-2 induction to repression of sterol transporters

Contact Info

Product

Resources

About