1
|
Huang J, Tao H, Yancey PG, Leuthner Z, May-Zhang LS, Jung JY, Zhang Y, Ding L, Amarnath V, Liu D, Collins S, Davies SS, Linton MF. Scavenging dicarbonyls with 5'-O-pentyl-pyridoxamine increases HDL net cholesterol efflux capacity and attenuates atherosclerosis and insulin resistance. Mol Metab 2022; 67:101651. [PMID: 36481344 PMCID: PMC9792904 DOI: 10.1016/j.molmet.2022.101651] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE Oxidative stress contributes to the development of insulin resistance (IR) and atherosclerosis. Peroxidation of lipids produces reactive dicarbonyls such as Isolevuglandins (IsoLG) and malondialdehyde (MDA) that covalently bind plasma/cellular proteins, phospholipids, and DNA leading to altered function and toxicity. We examined whether scavenging reactive dicarbonyls with 5'-O-pentyl-pyridoxamine (PPM) protects against the development of IR and atherosclerosis in Ldlr-/- mice. METHODS Male or female Ldlr-/- mice were fed a western diet (WD) for 16 weeks and treated with PPM versus vehicle alone. Plaque extent, dicarbonyl-lysyl adducts, efferocytosis, apoptosis, macrophage inflammation, and necrotic area were measured. Plasma MDA-LDL adducts and the in vivo and in vitro effects of PPM on the ability of HDL to reduce macrophage cholesterol were measured. Blood Ly6Chi monocytes and ex vivo 5-ethynyl-2'-deoxyuridine (EdU) incorporation into bone marrow CD11b+ monocytes and CD34+ hematopoietic stem and progenitor cells (HSPC) were also examined. IR was examined by measuring fasting glucose/insulin levels and tolerance to insulin/glucose challenge. RESULTS PPM reduced the proximal aortic atherosclerosis by 48% and by 46% in female and male Ldlr-/- mice, respectively. PPM also decreased IR and hepatic fat and inflammation in male Ldlr-/- mice. Importantly, PPM decreased plasma MDA-LDL adducts and prevented the accumulation of plaque MDA- and IsoLG-lysyl adducts in Ldlr-/- mice. In addition, PPM increased the net cholesterol efflux capacity of HDL from Ldlr-/- mice and prevented both the in vitro impairment of HDL net cholesterol efflux capacity and apoAI crosslinking by MPO generated hypochlorous acid. Moreover, PPM decreased features of plaque instability including decreased proinflammatory M1-like macrophages, IL-1β expression, myeloperoxidase, apoptosis, and necrotic core. In contrast, PPM increased M2-like macrophages, Tregs, fibrous cap thickness, and efferocytosis. Furthermore, PPM reduced inflammatory monocytosis as evidenced by decreased blood Ly6Chi monocytes and proliferation of bone marrow monocytes and HSPC from Ldlr-/- mice. CONCLUSIONS PPM has pleotropic atheroprotective effects in a murine model of familial hypercholesterolemia, supporting the therapeutic potential of reactive dicarbonyl scavenging in the treatment of IR and atherosclerotic cardiovascular disease.
Collapse
Affiliation(s)
- Jiansheng Huang
- Department of Medicine, Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Huan Tao
- Department of Medicine, Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Patricia G. Yancey
- Department of Medicine, Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Zoe Leuthner
- Department of Medicine, Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Linda S. May-Zhang
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States
| | - Ju-Yang Jung
- Department of Medicine, Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Youmin Zhang
- Department of Medicine, Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Lei Ding
- Department of Medicine, Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Venkataraman Amarnath
- Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Dianxin Liu
- Department of Medicine, Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Sheila Collins
- Department of Medicine, Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN, United States,Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, United States
| | - Sean S. Davies
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States
| | - MacRae F. Linton
- Department of Medicine, Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN, United States,Department of Pharmacology, Vanderbilt University, Nashville, TN, United States,Corresponding author. Department of Cardiovascular Medicine, Atherosclerosis Research Unit, Vanderbilt University Medical Center, 2220 Pierce Avenue, Nashville, TN, United States.
| |
Collapse
|
2
|
Krieger NS, Bushinsky DA. Metabolic Acidosis Regulates RGS16 and G-protein Signaling in Osteoblasts. Am J Physiol Renal Physiol 2021; 321:F424-F430. [PMID: 34396788 DOI: 10.1152/ajprenal.00166.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chronic metabolic acidosis stimulates cell-mediated net calcium efflux from bone mediated by increased osteoblastic cyclooxygenase 2 (COX2), leading to prostaglandin E2-induced stimulation of RANKL-induced osteoclastic bone resorption. The osteoblastic H+-sensing G-protein coupled receptor (GPCR), OGR1, is activated by acidosis and leads to increased bne resorption. As regulators of G protein signaling (RGS) proteins limit GPCR signaling, we tested whether RGS proteins themselves are regulated by metabolic acidosis. Primary osteoblasts were isolated from neonatal mouse calvariae and incubated in physiological neutral (NTL) or acidic (MET) medium. Cells were collected and RNA extracted for real time PCR analysis with mRNA levels normalized to RPL13a. RGS1, RGS2, RGS3, RGS4, RGS10, RGS11 or RGS18mRNA did not differ between MET and NTL; however by 30' MET decreased RGS16 which persisted for 60' and 3h. Incubation of osteoblasts with the OGR1 inhibitor CuCl2 inhibited the MET induced increase in RGS16 mRNA. Gallein, a specific inhibitor of Gβγ signaling, was used to determine if downstream signaling by the βγ subunit was critical for the response to acidosis. Gallein decreased net Ca efflux from calvariae and COX2 and RANKL gene expression from isolated osteoblasts. These results indicate that regulation of RGS16 plays an important role in modulating the response of the osteoblastic GPCR, OGR1, to metabolic acidosis and subsequent stimulation of osteoclastic bone resorption.
Collapse
Affiliation(s)
- Nancy S Krieger
- Division of Nephrology, Department of Medicine, University of Rochester Medical Center, Rochester, NY, United States
| | - David A Bushinsky
- Division of Nephrology, Department of Medicine, University of Rochester Medical Center, Rochester, NY, United States
| |
Collapse
|
3
|
Yoon H, Lee Y, Kang HJ, Ju J, Ji Y, Park H, Park H, Lee H, Holzapfel WH. Two putative probiotic strains improve diet-induced hypercholesterolemia through modulating intestinal cholesterol uptake and hepatic cholesterol efflux. J Appl Microbiol 2021; 132:562-570. [PMID: 34133840 DOI: 10.1111/jam.15181] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 06/07/2021] [Accepted: 06/08/2021] [Indexed: 11/30/2022]
Abstract
AIMS Two putative probiotic strains, Lacticaseibacillus (Lc.) rhamnosus BFE5264 and Lactiplantibacillus (Lp.) plantarum NR74, have been shown to suppress cholesterol uptake and promote cholesterol efflux in Caco-2 cells. However, an in vivo beneficial effect of these strains on plasma cholesterol levels has not been verified yet; neither have the underlying mechanisms of regulating cholesterol metabolism clarified thus far. This study has focused on these two aspects. METHODS AND RESULTS A murine model has been used, and the animals receiving a high-fat/high-cholesterol diet showed elevated plasma cholesterol levels. However, supplementation of Lc. rhamnosus BFE5264 and Lp. plantarum NR74 resulted in the down regulation of Niemann-Pick C1-like 1 (NPC1L1) in the intestine in addition to counteracting the diet-induced suppression of low-density lipoprotein receptor expression in the liver. ATP Binding Cassette Subfamily A Member 1 (ABCA1) was only significantly increased upon administration of Lc. rhamnosus BFE5264. CONCLUSIONS The present findings demonstrate that supplementation with Lc. rhamnosus BFE5264 and Lp. plantarum NR74 may improve diet-induced hypercholesterolemia by suppression of cholesterol absorption in the small intestine and by supporting the regulation of cholesterol metabolism in the liver. SIGNIFICANCE AND IMPACT OF THE STUDY This work contributes to understanding the beneficial effects of probiotics on host cholesterol metabolism and underlying mechanisms related to hypercholesterolemia.
Collapse
Affiliation(s)
- Hongsup Yoon
- Department of Advanced Convergence, Handong Global University, Pohang, Republic of Korea
| | - Yuri Lee
- Department of Advanced Convergence, Handong Global University, Pohang, Republic of Korea
| | - Hye-Ji Kang
- Department of Advanced Convergence, Handong Global University, Pohang, Republic of Korea
| | - Jaehyun Ju
- Department of Advanced Convergence, Handong Global University, Pohang, Republic of Korea
| | - Yosep Ji
- Department of Advanced Convergence, Handong Global University, Pohang, Republic of Korea
| | - Hyunjoon Park
- Department of Advanced Convergence, Handong Global University, Pohang, Republic of Korea
| | - Haryung Park
- Department of Advanced Convergence, Handong Global University, Pohang, Republic of Korea
| | - Heejae Lee
- Department of Advanced Convergence, Handong Global University, Pohang, Republic of Korea
| | - Wilhelm H Holzapfel
- Department of Advanced Convergence, Handong Global University, Pohang, Republic of Korea
| |
Collapse
|
4
|
Clift CL, Su YR, Bichell D, Jensen Smith HC, Bethard JR, Norris-Caneda K, Comte-Walters S, Ball LE, Hollingsworth MA, Mehta AS, Drake RR, Angel PM. Collagen fiber regulation in human pediatric aortic valve development and disease. Sci Rep 2021; 11:9751. [PMID: 33963260 PMCID: PMC8105334 DOI: 10.1038/s41598-021-89164-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 04/19/2021] [Indexed: 02/03/2023] Open
Abstract
Congenital aortic valve stenosis (CAVS) affects up to 10% of the world population without medical therapies to treat the disease. New molecular targets are continually being sought that can halt CAVS progression. Collagen deregulation is a hallmark of CAVS yet remains mostly undefined. Here, histological studies were paired with high resolution accurate mass (HRAM) collagen-targeting proteomics to investigate collagen fiber production with collagen regulation associated with human AV development and pediatric end-stage CAVS (pCAVS). Histological studies identified collagen fiber realignment and unique regions of high-density collagen in pCAVS. Proteomic analysis reported specific collagen peptides are modified by hydroxylated prolines (HYP), a post-translational modification critical to stabilizing the collagen triple helix. Quantitative data analysis reported significant regulation of collagen HYP sites across patient categories. Non-collagen type ECM proteins identified (26 of the 44 total proteins) have direct interactions in collagen synthesis, regulation, or modification. Network analysis identified BAMBI (BMP and Activin Membrane Bound Inhibitor) as a potential upstream regulator of the collagen interactome. This is the first study to detail the collagen types and HYP modifications associated with human AV development and pCAVS. We anticipate that this study will inform new therapeutic avenues that inhibit valvular degradation in pCAVS and engineered options for valve replacement.
Collapse
Affiliation(s)
- Cassandra L Clift
- Department of Cell and Molecular Pharmacology, MUSC Proteomics Center, Bruker-MUSC Clinical Glycomics Center of Excellence, Medical University of South Carolina, 173 Ashley Ave, BSB358, Charleston, SC, 29425, USA
| | - Yan Ru Su
- Division of Pediatric Cardiac Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - David Bichell
- Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Heather C Jensen Smith
- Eppley Institute for Cancer Research and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | | | | | | | | | - M A Hollingsworth
- Eppley Institute for Cancer Research and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Anand S Mehta
- Department of Cell and Molecular Pharmacology, MUSC Proteomics Center, Bruker-MUSC Clinical Glycomics Center of Excellence, Medical University of South Carolina, 173 Ashley Ave, BSB358, Charleston, SC, 29425, USA
| | - Richard R Drake
- Department of Cell and Molecular Pharmacology, MUSC Proteomics Center, Bruker-MUSC Clinical Glycomics Center of Excellence, Medical University of South Carolina, 173 Ashley Ave, BSB358, Charleston, SC, 29425, USA
| | - Peggi M Angel
- Department of Cell and Molecular Pharmacology, MUSC Proteomics Center, Bruker-MUSC Clinical Glycomics Center of Excellence, Medical University of South Carolina, 173 Ashley Ave, BSB358, Charleston, SC, 29425, USA.
| |
Collapse
|
5
|
Altered ADAMTS5 Expression and Versican Proteolysis: A Possible Molecular Mechanism in Barlow's Disease. Ann Thorac Surg 2018; 105:1144-1151. [DOI: 10.1016/j.athoracsur.2017.11.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 11/09/2017] [Accepted: 11/10/2017] [Indexed: 02/07/2023]
|
6
|
Do TM, Ouellet M, Calon F, Chimini G, Chacun H, Farinotti R, Bourasset F. Direct evidence of abca1-mediated efflux of cholesterol at the mouse blood-brain barrier. Mol Cell Biochem 2011; 357:397-404. [PMID: 21660464 DOI: 10.1007/s11010-011-0910-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 05/28/2011] [Indexed: 02/07/2023]
Abstract
We investigated the expression and function of Abca1 in wild-type C57BL/6, abca1(+/+), and abca1(-/-) mice brain capillaries forming the blood-brain barrier (BBB). We first demonstrated by quantitative RT-PCR and Western immunoblot that Abca1 was expressed and enriched in the wild-type mouse brain capillaries. In abca1(-/-) mice, we reported that the lack of Abca1 resulted in an 1.6-fold increase of the Abcg4 expression level compared to abca1(+/+) mice. Next, using the in situ brain perfusion technique, we showed that the [(3)H]cholesterol brain uptake clearance (Cl(up), μl/s/g brain), was significantly increased (107%) in abca1(-/-) mice compared to abca1(+/+) mice, meaning that the deficiency of Abca1 conducted to a significant decrease of the cholesterol efflux at the BBB level. In addition, the co-perfusion of probucol (Abca1 inhibitor) with [(3)H]cholesterol resulted in an increase of [(3)H]cholesterol Cl(up) (115%) in abca1(+/+) but not in abca1(-/-) mice, meaning that probucol inhibited selectively the efflux function of Abca1. In conclusion, our results demonstrated that Abca1 was expressed in the mouse brain capillaries and that Abca1 functions as an efflux transporter through the mouse BBB.
Collapse
Affiliation(s)
- Tuan Minh Do
- Laboratory of Clinical Pharmacy, EA4123, University of Paris Sud 11, 5 rue Jean-Baptiste Clément, 92296 Châtenay-Malabry, France
| | | | | | | | | | | | | |
Collapse
|
7
|
Krieger NS, Bushinsky DA. Pharmacological inhibition of intracellular calcium release blocks acid-induced bone resorption. Am J Physiol Renal Physiol 2010; 300:F91-7. [PMID: 21048027 DOI: 10.1152/ajprenal.00276.2010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In vivo chronic metabolic acidosis induces net Ca2+ efflux from bone, and incubation of neonatal mouse calvariae in medium simulating physiological metabolic acidosis induces bone resorption. It appears that activation of the proton (H+) receptor OGR1 in the osteoblast leads to an increase in intracellular Ca2+, which is associated with an increase in cyclooxygenase 2 (COX2) and PGE2-induced receptor activator of NF-κB ligand (RANKL) and H+-induced osteoclastic bone resorption. To support this hypothesis, we tested whether intracellular Ca2+ signaling was integral to H+-induced bone resorption by determining whether 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8) and 2-aminoethoxydiphenyl borate (2-APB), inhibitors of inositol trisphosphate-mediated Ca2+ signaling, would block H+-induced bone resorption in cultured neonatal calvariae and, if so, would do so by inhibiting H+-induced stimulation of COX2 and RANKL in osteoblastic cells. We found that H+-induced bone resorption is significantly inhibited by TMB-8 and 2-APB. Both compounds also inhibit H+-induced stimulation of COX2 protein in calvariae and COX2 mRNA and protein levels in primary osteoblasts. H+-induced stimulation of RANKL in calvarial cultures, as well as primary cells, is also completely inhibited by TMB-8 and 2-APB. These results support the hypothesis that H+ stimulation of net Ca2+ efflux from bone, mediated by COX2- and subsequent PGE2-induced RANKL production, is initiated in the osteoblast via activation of Ca2+ signaling.
Collapse
Affiliation(s)
- Nancy S Krieger
- University of Rochester School of Medicine and Dentistry, Division of Nephrology, Department of Medicine, 601 Elmwood Ave., Box 675, Rochester, NY 14642, USA.
| | | |
Collapse
|
8
|
Burke KT, Colvin PL, Myatt L, Graf GA, Schroeder F, Woollett LA. Transport of maternal cholesterol to the fetus is affected by maternal plasma cholesterol concentrations in the golden Syrian hamster. J Lipid Res 2009; 50:1146-55. [PMID: 19122238 PMCID: PMC2681396 DOI: 10.1194/jlr.m800538-jlr200] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2008] [Revised: 12/11/2008] [Indexed: 01/26/2023] Open
Abstract
The fetus has a high requirement for cholesterol and synthesizes cholesterol at elevated rates. Recent studies suggest that fetal cholesterol also can be obtained from exogenous sources. The purpose of the current study was to examine the transport of maternal cholesterol to the fetus and determine the mechanism responsible for any cholesterol-driven changes in transport. Studies were completed in pregnant hamsters with normal and elevated plasma cholesterol concentrations. Cholesterol feeding resulted in a 3.1-fold increase in the amount of LDL-cholesterol taken up by the fetus and a 2.4-fold increase in the amount of HDL-cholesterol taken up. LDL-cholesterol was transported to the fetus primarily by the placenta, and HDL-cholesterol was transported by the yolk sac and placenta. Several proteins associated with sterol transport and efflux, including those induced by activated liver X receptor, were expressed in hamster and human placentas: NPC1, NPC1L1, ABCA2, SCP-x, and ABCG1, but not ABCG8. NPC1L1 was the only protein increased in hypercholesterolemic placentas. Thus, increasing maternal lipoprotein-cholesterol concentrations can enhance transport of maternal cholesterol to the fetus, leading to 1) increased movement of cholesterol down a concentration gradient in the placenta, 2) increased lipoprotein secretion from the yolk sac (shown previously), and possibly 3) increased placental NPC1L1 expression.
Collapse
MESH Headings
- Animals
- Biological Transport, Active
- Cholesterol/blood
- Cholesterol/metabolism
- Cholesterol, Dietary/administration & dosage
- Cholesterol, HDL/blood
- Cholesterol, HDL/metabolism
- Cholesterol, LDL/blood
- Cholesterol, LDL/metabolism
- Cricetinae
- DNA-Binding Proteins/metabolism
- Female
- Fetus/metabolism
- Humans
- Infant, Newborn
- Liver X Receptors
- Male
- Maternal-Fetal Exchange/genetics
- Maternal-Fetal Exchange/physiology
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Membrane Transport Proteins
- Mesocricetus
- Orphan Nuclear Receptors
- Placenta/metabolism
- Pregnancy
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Cytoplasmic and Nuclear/metabolism
- Smith-Lemli-Opitz Syndrome/blood
- Smith-Lemli-Opitz Syndrome/metabolism
- Yolk Sac/metabolism
Collapse
Affiliation(s)
- Katie T. Burke
- Department of Pathology and Laboratory Medicine, University of Cincinnati Medical School, Cincinnati, OH 45237
| | - Perry L. Colvin
- Department of Internal Medicine and Division of Gerontology, University of Maryland School of Medicine and the Baltimore Veterans Affairs Medical Center, Geriatrics Research, Education, and Clinical Center, Baltimore, MD 21201
| | - Leslie Myatt
- Department of Obstetrics/Gynecology, University of Cincinnati Medical School, Cincinnati, OH 45237
| | - Gregory A. Graf
- Department of Pharmaceutical Sciences and Cardiovascular Research Center, University of Kentucky, Lexington, KY 40536
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX 77843
| | - Laura A. Woollett
- Department of Pathology and Laboratory Medicine, University of Cincinnati Medical School, Cincinnati, OH 45237
| |
Collapse
|
9
|
Su YR, Blakemore JL, Zhang Y, Linton MF, Fazio S. Lentiviral transduction of apoAI into hematopoietic progenitor cells and macrophages: applications to cell therapy of atherosclerosis. Arterioscler Thromb Vasc Biol 2008; 28:1439-46. [PMID: 18497309 PMCID: PMC2744493 DOI: 10.1161/atvbaha.107.160093] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE We used genetically engineered mouse hematopoietic progenitor cells (HPCs) to investigate the therapeutic effects of human apoAI on atherosclerosis in apoE(-/-) mice. METHODS AND RESULTS Lentiviral constructs expressing either human apoAI (LV-apoAI) or green fluorescent protein (LV-GFP) cDNA under a macrophage specific promoter (CD68) were generated and used for ex vivo transduction of mouse HPCs and macrophages. The transduction efficiency was >25% for HPCs and >70% for macrophages. ApoAI was found in the macrophage culture media, mostly associated with the HDL fraction. Interestingly, a significant increase in mRNA and protein levels for ATP binding cassette A1 (ABCA1) and ABCG1 were found in apoAI-expressing macrophages after acLDL loading. Expression of apoAI significantly increased cholesterol efflux in wild-type and apoE(-/-) macrophages. HPCs transduced with LV-apoAI ex vivo and then transplanted into apoE(-/-) mice caused a 50% reduction in atherosclerotic lesion area compared to GFP controls, without influencing plasma HDL-C levels. CONCLUSIONS Lentiviral transduction of apoAI into HPCs reduces atherosclerosis in apoE(-/-) mice. Expression of apoAI in macrophages improves cholesterol trafficking in wild-type apoE-producing macrophages and causes upregulation of ABCA1 and ABCG1. These novel observations set the stage for a cell therapy approach to atherosclerosis regression, exploiting the cooperation between apoE and apoAI to maximize cholesterol exit from the plaque.
Collapse
Affiliation(s)
- Yan Ru Su
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville TN 37232-6300, USA.
| | | | | | | | | |
Collapse
|
10
|
Kim WS, Weickert CS, Garner B. Role of ATP-binding cassette transporters in brain lipid transport and neurological disease. J Neurochem 2008; 104:1145-66. [DOI: 10.1111/j.1471-4159.2007.05099.x] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
11
|
Krieger NS, Frick KK, LaPlante Strutz K, Michalenka A, Bushinsky DA. Regulation of COX-2 mediates acid-induced bone calcium efflux in vitro. J Bone Miner Res 2007; 22:907-17. [PMID: 17352658 DOI: 10.1359/jbmr.070316] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
UNLABELLED Chronic metabolic acidosis induces net Ca efflux from bone; this osteoclastic bone resorption is mediated by increased osteoblastic prostaglandin synthesis. Cyclooxygenase, the rate-limiting enzyme in prostaglandin synthesis, is present in both constitutive (COX-1) and inducible (COX-2) forms. We report here that acidosis increases both osteoblastic RNA and protein levels for COX-2 and that genetic deficiency or pharmacologic inhibition of COX-2 significantly reduces acid-induced Ca efflux from bone. INTRODUCTION Incubation of neonatal mouse calvariae in medium simulating physiologic metabolic acidosis induces an increase in osteoblastic prostaglandin E2 (PGE2) release and net calcium (Ca) efflux from bone. Increased PGE2 is necessary for acid-induced bone resorption, because inhibition of cyclooxygenase activity with indomethacin significantly decreases not only PGE2 production but also Ca release. Cyclooxygenase is present in both constitutive (COX-1) and inducible (COX-2) forms. Because COX-2 activity has been implicated in several forms of pathological bone resorption, we tested the hypothesis that COX-2 is critical for acid-induced, cell-mediated bone Ca efflux. MATERIALS AND METHODS To determine the effect of metabolic acidosis on COX-2 RNA and protein, primary cells isolated from neonatal CD-1 mouse calvariae were cultured in neutral (Ntl) or physiologically acidic medium (Met). RNA levels for COX-2 and COX-1 were measured by quantitative real-time PCR. Levels of COX-2 and COX-1 protein were measured by immunoblot analysis. To determine the effect of acidosis on bone Ca efflux in genetically deficient COX-2 mice, mice heterozygous for the COX-2 knockout (strain B6;129S7-Ptgs2(tm1Jed)/J) were used as breeders, and neonatal calvariae were cultured in Ntl or Met. To determine the effects of the specific COX-2 inhibitor, NS398, on acid-induced bone resorption, CD-1 calvariae were incubated in Ntl or Met with or without NS398 (1 microM). Medium PGE2 was assayed by ELISA. RESULTS Incubation of mouse calvarial cells in Met significantly increased COX-2 RNA and protein levels without a change in COX-1. Increased COX-2 protein levels in response to Met were also observed in cultured calvariae. Acid-induced, cell-mediated Ca efflux from B6;129S7-Ptgs2(tm1Jed)/J calvariae was dependent on genotype. From 0 to 24 h, when physicochemical Ca efflux predominates, Met significantly increased net Ca efflux in all genotypes. After 24 h, when cell-mediated Ca efflux predominates, Met induced greater Ca efflux from (+/+) than from (+/-), and there was no increase from (-/-). In calvariae from CD-1 mice, NS398 significantly inhibited both the acid-induced increase in PGE2 and Ca release. CONCLUSIONS The specific acid-induced increase in COX-2 RNA and protein levels and the dependency of the increased Ca efflux on COX-2 activity, as determined by both genetic deficiency and pharmacologic inhibition, show that COX-2 is critical for acid-induced, cell-mediated bone resorption.
Collapse
Affiliation(s)
- Nancy S Krieger
- Department of Medicine, Division of Nephrology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
| | | | | | | | | |
Collapse
|
12
|
Zhuge X, Arai H, Xu Y, Murayama T, Kobayashi T, Narumiya S, Kita T, Yokode M. Protection of atherogenesis in thromboxane A2 receptor-deficient mice is not associated with thromboxane A2 receptor in bone marrow-derived cells. Biochem Biophys Res Commun 2006; 351:865-71. [PMID: 17097058 DOI: 10.1016/j.bbrc.2006.10.121] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Accepted: 10/23/2006] [Indexed: 10/24/2022]
Abstract
In the previous study, we generated mice lacking thromboxane A2 receptor (TP) and apolipoprotein E, apoE(-/-)TP(-/-) mice, and reported that the double knockout mice developed markedly smaller atherosclerotic lesions than those in apoE(-/-) mice. To investigate the mechanism responsible for reduced atherosclerosis in apoE(-/-)TP(-/-) mice, we examined the role of TP in bone marrow (BM)-derived cells in the development of the atherosclerotic lesions. When we compared the function of macrophages in apoE(-/-) and in apoE(-/-)TP(-/-) mouse in vitro, there was no difference in the expression levels of cytokines and chemokines after stimulation with lipopolysaccharide. We then transplanted the BM from either apoE(-/-) or apoE(-/-)TP(-/-) mice to either apoE(-/-) or apoE(-/-)TP(-/-) mice after sublethal irradiation. After 12 weeks with high fat diet, we analyzed the atherosclerotic lesion of aortic sinus. When the BM from apoE(-/-) or apoE(-/-)TP(-/-) mice was transplanted to apoE(-/-) mice, the lesion size was almost the same as that of apoE(-/-) mice without BM transplantation. In contrast, when the BM from apoE(-/-) or apoE(-/-)TP(-/-) mice was transplanted to apoE(-/-)TP(-/-) mice, the lesion size was markedly reduced. These results indicate that the protection of atherogenesis in TP(-/-) mice is not associated with TP in BM-derived cells.
Collapse
Affiliation(s)
- Xin Zhuge
- Department of Clinical Innovative Medicine, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Yanagihara H, Ando H, Hayashi Y, Obi Y, Fujimura A. High-fat feeding exerts minimal effects on rhythmic mRNA expression of clock genes in mouse peripheral tissues. Chronobiol Int 2006; 23:905-14. [PMID: 17050208 DOI: 10.1080/07420520600827103] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Recent studies have suggested that the impairment of the circadian molecular clock in peripheral tissues, including adipose tissue, is involved in the development of metabolic syndrome. Although the disorder is often caused by dietary obesity, it remains to be elucidated whether dietary obesity or high-caloric intake per se affects the molecular clock system. To address this issue, this study investigated the effect of high-fat feeding on the rhythmic mRNA expression of clock genes (Clock, Bmal1, Per1, Per2, Cry1, Cry2, and Dbp) in mouse visceral adipose tissue and liver. Mice fed a high-fat diet for 8 wks developed a mild but overt metabolic syndrome of obesity, hyperlipidemia, and hyperglycemia. However, the high-fat feeding had only minimal effects on the rhythmic expression of the clock genes examined in both tissues. On the other hand, daily rhythmicity in the transcript level of cholesterol 7alpha-hydroxylase, a hepatic enzyme controlling circadian cholesterol homeostasis, disappeared in the mice on high-fat chow. These results suggest that high-fat feeding and mild metabolic syndrome scarcely alter the molecular clock system in mouse peripheral tissues, and that physiological circadian rhythms could be affected without altering the system. Further studies are needed to better understand the role of the circadian molecular clock in the development of metabolic syndrome. The first two authors contributed equally to this study.
Collapse
Affiliation(s)
- Hayato Yanagihara
- Division of Clinical Pharmacology, Department of Pharmacology, Jichi Medical School, Shimotsuke, Tochigi 329-0498, Japan
| | | | | | | | | |
Collapse
|
14
|
Yamamoto H, Tsuruoka S, Ioka T, Ando H, Ito C, Akimoto T, Fujimura A, Asano Y, Kusano E. Indoxyl sulfate stimulates proliferation of rat vascular smooth muscle cells. Kidney Int 2006; 69:1780-5. [PMID: 16612331 DOI: 10.1038/sj.ki.5000340] [Citation(s) in RCA: 195] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Vascular smooth muscle cell (VSMC) proliferation is a key event in the progression of arteriosclerosis. Clinical studies show that uremic toxins deteriorate the arteriosclerosis in renal failure patients. Indoxyl sulfate (IS) is a strong protein-bound uremic toxin, but the effect of IS on VSMC proliferation has not been studied. We examined the effect of IS on rat VSMC proliferation, assessed by a cell counting kit (4-[3-[4-lodophenyl]-2-4(4-nitrophenyl)-2H-5-tetrazolio-1,3-benzene disulfonate] assay) and by [(3)H]thymidine incorporation in vitro. We further evaluated a contribution of mitogen-activated protein kinase (MAPK; p44/42 MAPK) to VSMC proliferation by IS. Immunohistochemical staining was performed for VSMCs using antirat organic anion transporter (OAT)3 antibody. The mRNA expressions of platelet-derived growth factor (PDGF)-A and -C chains, and PDGF-beta receptor were evaluated by real-time PCR. IS stimulated the proliferation of VSMCs in a concentration-dependent manner and activated p44/42 MAPK. Concentration of IS needed to stimulate the proliferation of rat VSMC was about 250 microM, which is compatible with that in the serum of end-stage renal failure patients. PD98059 (10 microM), a selective inhibitor of MAPK/extracellular signal-regulated kinase, inhibited the IS-induced (250 microM) VSMC proliferation and phosphorylation of MAPK. Probenecid (0.5 mM), an inhibitor and substrate of OAT, inhibited the IS-induced (250 microM) VSMC proliferation. Rat OAT3 was detected in VSMCs. The mRNA expressions of PDGF-C chain and PDGF-beta receptor were significantly increased by IS. We conclude that IS directly stimulates rat VSMC proliferation and activates MAPK in vitro. This might be one of the mechanisms underlying the progression of atherosclerotic lesions in end-stage renal disease patients.
Collapse
Affiliation(s)
- H Yamamoto
- Department of Nephrology, Jichi Medical School, Tochigi, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Gigante B, Morlino G, Gentile MT, Persico MG, De Falco S. Plgf−/−eNos−/−mice show defective angiogenesis associated with increased oxidative stress in response to tissue ischemia. FASEB J 2006; 20:970-2. [PMID: 16608872 DOI: 10.1096/fj.05-4481fje] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Neo-angiogenesis is a complex phenomenon modulated by the concerted action of several molecular factors. We have generated a congenic line of knockout mice carrying null mutations of both placental growth factor (PlGF) and endothelial nitric oxide synthase (eNOS), two genes that play a pivotal role in the regulation of pathological angiogenesis. In the present study, we describe the phenotype of this new experimental animal model after surgically induced hind-limb ischemia. Plgf-/-, eNos-/-, Plgf-/- eNos-/-, and wild-type C57BL/6J mice were studied. Plgf-/- eNos-/- mice showed the most severe phenotype: self-amputation, and death occurred in up to 47% of the animals studied; in ischemic legs, capillary density was severely reduced; macrophage infiltration and oxidative stress increased as compared to the other groups of animals. These changes were associated with an up-regulation of both inducible NOS (iNOS) expression and vascular endothelial growth factor (VEGF) protein levels in ischemic limbs, and to an increased extent of protein nitration. Our results demonstrate that the deletion of these two genes, Plgf, which acts in synergism with VEGF, and eNos, a downstream mediator of VEGF, determines a significant change in the vascular response to an ischemic stimulus and that oxidative stress within the ischemic tissue represents a crucial factor to maintain tissue homeostasis.
Collapse
Affiliation(s)
- Bruna Gigante
- Institute of Genetics and Biophysics Adriano Buzzati-Traverso, Consiglio Nazionale delle Ricerche, Via P. Castellino, 111, Naples 80131, Italy
| | | | | | | | | |
Collapse
|
16
|
Wakaumi M, Ishibashi K, Ando H, Kasanuki H, Tsuruoka S. Acute digoxin loading reduces ABCA8A mRNA expression in the mouse liver. Clin Exp Pharmacol Physiol 2006; 32:1034-41. [PMID: 16445568 DOI: 10.1111/j.1440-1681.2005.04301.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Human ABCA8, a new member of the ATP binding cassette (ABC) transporter family, transports certain lipophilic drugs, such as digoxin. To investigate the roles of this transporter, we cloned a mouse homologue of ABCA8, from a mouse heart cDNA library, named ABCA8a. The deduced mouse ABCA8a protein is 66% identical with that of human ABCA8 and possesses features common to the ABC superfamily. It was found that ABCA8a was mainly expressed in the liver and heart, similar to human ABCA8. We further evaluated the effect of acute digoxin (a substrate for ABCA8) intoxication on the mRNA expression of ABCA8 using northern blotting with a 3' non-coding region as a probe to avoid cross-hybridization with other ABCA genes. Following acute digoxin infusion, the mRNA expression of ABCA8 was significantly reduced in the liver 12-24 h after injection (14.7% of vehicle treatment), but not in the heart and kidney. Real-time quantitative polymerase chain reaction analysis confirmed the reduction in ABCA8a mRNA. Similar reductions in ABCA5, ABCA7, ABCA8b and ABCA9 mRNA were also observed. A comparable amount of digitoxin did not affect ABCA8a mRNA expression in the liver. The results suggest that ABCA8 may play a role in digoxin metabolism in the liver.
Collapse
Affiliation(s)
- Michi Wakaumi
- Department of Pharmacology, Division of Clinical Pharmacology, Jichi Medical School, Kawachi, Tochigi, Japan
| | | | | | | | | |
Collapse
|
17
|
Nishimura M, Naito S. Tissue-specific mRNA expression profiles of human ATP-binding cassette and solute carrier transporter superfamilies. Drug Metab Pharmacokinet 2006; 20:452-77. [PMID: 16415531 DOI: 10.2133/dmpk.20.452] [Citation(s) in RCA: 296] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pairs of forward and reverse primers and TaqMan probes specific to each of 46 human ATP-binding cassette (ABC) transporters and 108 human solute carrier (SLC) transporters were prepared. The mRNA expression level of each target transporter was analyzed in total RNA from single and pooled specimens of various human tissues (adrenal gland, bone marrow, brain, colon, heart, kidney, liver, lung, pancreas, peripheral leukocytes, placenta, prostate, salivary gland, skeletal muscle, small intestine, spinal cord, spleen, stomach, testis, thymus, thyroid gland, trachea, and uterus) by real-time reverse transcription PCR using an ABI PRISM 7700 sequence detector system. In contrast to previous methods for analyzing the mRNA expression of single ABC and SLC genes such as Northern blotting, our method allowed us to perform sensitive, semiautomatic, rapid, and complete analysis of ABC and SLC transporters in total RNA samples. Our newly determined expression profiles were then used to study the gene expression in 23 different human tissues, and tissues with high transcriptional activity for human ABC and SLC transporters were identified. These results are expected to be valuable for establishing drug transport-mediated screening systems for new chemical entities in new drug development and for research concerning the clinical diagnosis of disease.
Collapse
Affiliation(s)
- Masuhiro Nishimura
- Division of Pharmacology, Drug Safety and Metabolism, Otsuka Pharmaceutical Factory, Inc., Tokushima, Japan.
| | | |
Collapse
|
18
|
Ando H, Yanagihara H, Hayashi Y, Obi Y, Tsuruoka S, Takamura T, Kaneko S, Fujimura A. Rhythmic messenger ribonucleic acid expression of clock genes and adipocytokines in mouse visceral adipose tissue. Endocrinology 2005; 146:5631-6. [PMID: 16166217 DOI: 10.1210/en.2005-0771] [Citation(s) in RCA: 236] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Various peripheral tissues show circadian rhythmicity, which is generated at the cellular level by their own core oscillators that are composed of transcriptional/translational feedback loops involving a set of clock genes. Although the circulating levels of some adipocytokines, i.e. bioactive substances secreted by adipocytes, are on a 24-h rhythmic cycle, it remains to be elucidated whether the clock gene system works in adipose tissue. To address this issue, we investigated the daily mRNA expression profiles of the clock genes and adipocytokines in mouse perigonadal adipose tissues. In C57BL/6J mice, all transcript levels of the clock genes (Bmal1, Per1, Per2, Cry1, Cry2, and Dbp) and adipocytokines (adiponectin, resistin, and visfatin) clearly showed 24-h rhythms. On the other hand, the rhythmic expression of these genes was mildly attenuated in obese KK mice and greatly attenuated in more obese, diabetic KK-A(y) mice. Obese diabetes also diminished the rhythmic expression of the clock genes in the liver. Interestingly, a 2-wk treatment of KK and KK-A(y) mice with pioglitazone impaired the 24-h rhythmicity of the mRNA expression of the clock genes and adipocytokines despite the antidiabetic effect of the drug. In contrast, pioglitazone improved the attenuated rhythmicity in the liver. These findings suggest that the intracellular clock gene system acts in visceral adipose tissues as well as liver and is influenced by the conditions of obesity/type 2 diabetes and pioglitazone treatment.
Collapse
Affiliation(s)
- Hitoshi Ando
- Division of Clinical Pharmacology, Department of Pharmacology, Jichi Medical School, Tochigi, Japan
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Ando H, Yanagihara H, Sugimoto KI, Hayashi Y, Tsuruoka S, Takamura T, Kaneko S, Fujimura A. Daily rhythms of P-glycoprotein expression in mice. Chronobiol Int 2005; 22:655-65. [PMID: 16147897 DOI: 10.1080/07420520500180231] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Recent studies have shown the gene expression of several transporters to be circadian rhythmic. However, it remains to be elucidated whether the expression of P-glycoprotein, which is involved in the transport of many medications, undergoes 24 h rhythmicity. To address this issue, we investigated daily profiles of P-glycoprotein mRNA and protein levels in peripheral mouse tissues. In the liver and intestine, but not in the kidney, Abcb1a mRNA expression showed clear 24 h rhythmicity. On the other hand, Abcb1b and Abcb4, the other P-glycoprotein genes, did not exhibit significant rhythmic expression in the studied tissues. In the intestine, levels of whole P-glycoprotein also exhibited a daily rhythm, with a peak occurring in the latter half of the light phase and a trough at the onset of the light phase. Consistent with the day-night change of P-glycoprotein level, the ex vivo accumulation of digoxin, an Abcb1a P-glycoprotein substrate, into the intestinal segments at the onset of dark phase was significantly lower than it was at the onset of the light phase. Thus, Abcb1a P-glycoprotein expression, and apparently its function, are 24 h rhythmic at least in mouse intestine tissue. This circadian variation might be involved in various chronopharmacological phenomena.
Collapse
Affiliation(s)
- Hitoshi Ando
- Division of Clinical Pharmacology, Department of Pharmacology, Jichi Medical School, Minami-kawachi, Tochigi, Japan
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Sabol SL, Brewer HB, Santamarina-Fojo S. The human ABCG1 gene: identification of LXR response elements that modulate expression in macrophages and liver. J Lipid Res 2005; 46:2151-67. [PMID: 16024918 DOI: 10.1194/jlr.m500080-jlr200] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ABC transporter ABCG1 (ATP binding cassette transporter G1), expressed in macrophages, liver, and other tissues, has been implicated in the efflux of cholesterol to high density lipoprotein. The ABCG1 gene is transcriptionally activated by cholesterol loading and activators of liver X receptors (LXRs) and retinoid X receptors (RXRs) through genomic sequences that have not been fully characterized. Here we show that ABCG1 mRNA is induced by LXR agonists in RAW264.7 macrophage cells, HepG2 hepatoma cells, and primary mouse hepatocytes. We identify two evolutionarily highly conserved LXR response elements (LXREs), LXRE-A and LXRE-B, located in the first and second introns of the human ABCG1 gene. Each element conferred robust LXR-agonist responsiveness to ABCG1 promoter-directed luciferase gene constructs in RAW264.7 and HepG2 cells. Overexpression of LXR/RXR activated the ABCG1 promoter in the presence of LXRE-A or LXRE-B sequences. In gel-shift assays, LXR/RXR heterodimers bound to wild-type but not to mutated LXRE-A and LXRE-B sequences. In chromatin immunoprecipitation assays, LXR and RXR were detected at LXRE-A and -B regions of DNA of human THP-1 macrophages. These studies clarify the mechanism of transcriptional upregulation of the ABCG1 gene by oxysterols in macrophages and liver, two key tissues where ABCG1 expression may affect cholesterol balance and atherogenesis.
Collapse
Affiliation(s)
- Steven L Sabol
- Molecular Disease Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | | | | |
Collapse
|
21
|
Viveiros M, Jesus A, Brito M, Leandro C, Martins M, Ordway D, Molnar AM, Molnar J, Amaral L. Inducement and reversal of tetracycline resistance in Escherichia coli K-12 and expression of proton gradient-dependent multidrug efflux pump genes. Antimicrob Agents Chemother 2005; 49:3578-82. [PMID: 16048990 PMCID: PMC1196278 DOI: 10.1128/aac.49.8.3578-3582.2005] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Expression of eight transporter genes of Escherichia coli K-12 and its DeltaacrAB mutant prior to and after induction of both strains to tetracycline resistance and after reversal of induced resistance were analyzed by quantitative reverse transcriptase PCR. All transporter genes were overexpressed after induced resistance with acrF being 80-fold more expressed in the DeltaacrAB tetracycline-induced strain.
Collapse
Affiliation(s)
- Miguel Viveiros
- Unit of Mycobacteriology, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua Junqueira 96, 1349-008 Lisbon, Portugal
| | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Dove DE, Su YR, Swift LL, Linton MF, Fazio S. ACAT1 deficiency increases cholesterol synthesis in mouse peritoneal macrophages. Atherosclerosis 2005; 186:267-74. [PMID: 16144700 DOI: 10.1016/j.atherosclerosis.2005.08.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2004] [Revised: 07/20/2005] [Accepted: 08/01/2005] [Indexed: 11/30/2022]
Abstract
Acyl-coenzyme A:cholesterol acyltransferase (ACAT) esterifies free cholesterol and stores cholesteryl esters in lipid droplets. Macrophage ACAT1 deficiency results in increased atherosclerotic lesion area in hyperlipidemic mice via disrupted cholesterol efflux, increased lipoprotein uptake, accumulation of intracellular vesicles, and accelerated apoptosis. The objective of this study was to determine whether lipid synthesis is affected by ACAT1. The synthesis, esterification, and efflux of new cholesterol were measured in peritoneal macrophages from ACAT1(-/-) mice. Cholesterol synthesis was increased by 134% (p=0.001) in ACAT1(-/-) macrophages compared to wildtype macrophages. Increased synthesis resulted in a proportional increase in the efflux of newly synthesized cholesterol. Although the esterification of new cholesterol was reduced by 93% (p<0.001) in ACAT1(-/-) macrophages, trace amounts of newly synthesized cholesteryl esters were detectable. Furthermore, the expression of SREBP1a mRNA was increased 6-fold in ACAT1(-/-) macrophages compared to wildtype macrophages, suggesting an up-regulation of cholesterol and fatty acid synthesis in ACAT1(-/-) macrophages. Increased cholesterol synthesis and up-regulation of SREBP in ACAT1(-/-) macrophages suggests that ACAT1 affects the regulation of lipid metabolism in macrophages. This change in cholesterol homeostasis may contribute to the atherogenic potential of ACAT1(-/-) macrophages.
Collapse
Affiliation(s)
- Dwayne E Dove
- Department of Pathology, Vanderbilt University Medical Center, Nashville, TN 37232-6300, USA
| | | | | | | | | |
Collapse
|
23
|
Swift LL, Kakkad B, Boone C, Jovanovska A, Jerome WG, Mohler PJ, Ong DE. Microsomal triglyceride transfer protein expression in adipocytes: a new component in fat metabolism. FEBS Lett 2005; 579:3183-9. [PMID: 15922333 DOI: 10.1016/j.febslet.2005.05.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2005] [Revised: 04/29/2005] [Accepted: 05/09/2005] [Indexed: 11/26/2022]
Abstract
Microsomal triglyceride transfer protein (MTP) is a carrier of triglyceride essential for the assembly of apolipoprotein (apo)B-containing lipoproteins by the liver and the small intestine. Its role in triglyceride transfer in tissues that do not secrete lipoproteins has not been explored. In particular, MTP would seem to be a candidate for a role in triglyceride metabolism within the adipocyte. To test this hypothesis, we probed adipocytes for the presence of MTP. Immunohistochemical and biochemical studies demonstrate MTP in adipocytes from brown and white fat depots of mice and human, as well as in 3T3-L1 cells. Confocal microscopy revealed MTP throughout 3T3 cells; however, MTP fluorescence was prominent in juxtanuclear areas. In differentiated 3T3 cells MTP fluorescence was very striking around lipid droplets. In vitro lipid transfer assays demonstrated the presence of triglyceride transfer activity within microsomal fractions isolated from rat adipose tissue. In addition, quantitative rtPCR studies showed that MTP expression in mouse white fat depots was approximately 1% of MTP expression in mouse liver. MTP mRNA in differentiated 3T3 cells was approximately 13% of liver expression. Our results provide unequivocal evidence for the presence of MTP in adipocytes and present new possibilities for defining the mechanisms by which triglyceride is stored and/or hydrolyzed and mobilized.
Collapse
Affiliation(s)
- Larry L Swift
- Department of Pathology, C-3321 Medical Center North, Vanderbilt University School of Medicine, Nashville, TN 37232-2561, USA.
| | | | | | | | | | | | | |
Collapse
|
24
|
Ando H, Tsuruoka S, Yamamoto H, Takamura T, Kaneko S, Fujimura A. Regulation of cholesterol 7alpha-hydroxylase mRNA expression in C57BL/6 mice fed an atherogenic diet. Atherosclerosis 2005; 178:265-9. [PMID: 15694933 DOI: 10.1016/j.atherosclerosis.2004.09.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2004] [Revised: 08/31/2004] [Accepted: 09/10/2004] [Indexed: 10/26/2022]
Abstract
The nuclear receptors liver X receptor (LXR) alpha and farnesoid X receptor (FXR) are positive and negative regulators of cholesterol 7alpha-hydroxylase (CYP7A1) transcription, respectively. To clarify their roles in the regulation of CYP7A1 in mice, we investigated mRNA expression of their target genes in the livers of C57BL/6 mice fed the following five diets for 2 weeks: a standard diet, cholic acid, cholesterol, cholesterol+high fat, or an atherogenic diet (cholic acid+cholesterol+high fat). The mRNA level of ATP-binding cassette transporter (ABC) A1 gene, one of LXRalpha target genes, significantly increased on the diets containing cholic acid and/or cholesterol+high fat, but not on the diet containing cholesterol alone. On the other hand, the mRNA levels of the FXR target genes ABCB11, ABCC2, and short heterodimer partner increased only on the diet containing cholic acid with or without cholesterol+high fat. Surprisingly, cholesterol alone or cholesterol+high fat did not affect CYP7A1 mRNA level, whereas cholic acid with or without cholesterol+high fat greatly reduced the level. Thus, in the atherogenic diet-fed mice, cholic acid component is needed for the FXR activation, and FXR dominantly regulates CYP7A1 transcription.
Collapse
Affiliation(s)
- Hitoshi Ando
- Division of Clinical Pharmacology, Department of Pharmacology, Jichi Medical School, Tochigi 329-0498, Japan
| | | | | | | | | | | |
Collapse
|
25
|
Ile KE, Davis W, Boyd JT, Soulika AM, Tew KD. Identification of a novel first exon of the human ABCA2 transporter gene encoding a unique N-terminus. ACTA ACUST UNITED AC 2005; 1678:22-32. [PMID: 15093135 DOI: 10.1016/j.bbaexp.2004.01.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2003] [Revised: 01/23/2004] [Accepted: 01/23/2004] [Indexed: 11/16/2022]
Abstract
The human ABCA2 transporter is a member of a large family of ATP-binding proteins that transport a variety of molecules across biological membranes. Using RNA ligation-mediated PCR (RLM-PCR), we have identified a novel first exon, which we designate 1B that is located 699 bp upstream of the previously characterized first exon, which we designate 1A. These first exons are alternatively spliced to the second exon of the ABCA2 transcript resulting in a protein that has a unique amino terminus. For exon 1B, the new amino terminus encoded by the first exon is 52 amino acids and for exon 1A, 22 amino acids. We observed that among adult tissues examined, the highest expression of the 1B isoform was in peripheral blood leukocytes (PBL). Laser scanning confocal microscopy revealed that the 1A isoform and the 1B isoform co-localize with lysosome-associated membrane proteins-1 and -2 (LAMP-1 and -2). Cytotoxicity assays suggested a role for ABCA2 in estramustine and estradiol resistance, and overexpression of ABCA2 is seen in an estramustine-resistant prostate carcinoma line. Since both isoforms of the ABCA2 transporter have identical subcellular localization and both are overexpressed in a resistant cell line, we propose that they are also functionally redundant. It is likely that expression of ABCA2 by two independent promoters constitutes locus of regulation controlling expression of the protein to meet requirements in different tissues.
Collapse
Affiliation(s)
- Kristina E Ile
- Department of Pharmacology, Fox Chase Cancer Center, 333 Cottman Ave., Philadelphia, PA 19111, USA
| | | | | | | | | |
Collapse
|
26
|
Su YR, Dove DE, Major AS, Hasty AH, Boone B, Linton MF, Fazio S. Reduced ABCA1-Mediated Cholesterol Efflux and Accelerated Atherosclerosis in Apolipoprotein E–Deficient Mice Lacking Macrophage-Derived ACAT1. Circulation 2005; 111:2373-81. [PMID: 15851589 DOI: 10.1161/01.cir.0000164236.19860.13] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
Macrophage acyl-coenzyme A:cholesterol acyltransferase 1 (ACAT1) and apolipoprotein E (apoE) have been implicated in regulating cellular cholesterol homeostasis and therefore play critical roles in foam cell formation. Deletion of either ACAT1 or apoE results in increased atherosclerosis in hyperlipidemic mice, possibly as a consequence of altered cholesterol processing. We have studied the effect of macrophage ACAT1 deletion on atherogenesis in apoE-deficient (apoE
−/−
) mice with or without the restoration of macrophage apoE.
Methods and Results—
We used bone marrow transplantation to generate apoE
−/−
mice with macrophages of 4 genotypes: apoE
+/+
/ACAT1
+/+
(wild type), apoE
+/+
/ACAT1
−/−
(ACAT
−/−
), apoE
−/−
/ACAT1
+/+
(apoE
−/−
), and apoE
−/−
/ACAT1
−/−
(2KO). When macrophage apoE was present, plasma cholesterol levels normalized, and ACAT1 deficiency did not have significant effects on atherogenesis. However, when macrophage apoE was absent, ACAT1 deficiency increased atherosclerosis and apoptosis in the proximal aorta. Cholesterol efflux to apoA-I was significantly reduced (30% to 40%;
P
<0.001) in ACAT1
−/−
peritoneal macrophages compared with ACAT1
+/+
controls regardless of apoE expression. 2KO macrophages had a 3- to 4-fold increase in ABCA1 message levels but decreased ABCA1 protein levels relative to ACAT1
+/+
macrophages. Microarray analyses of ACAT1
−/−
macrophages showed increases in proinflammatory and procollagen genes and decreases in genes regulating membrane integrity, protein biosynthesis, and apoptosis.
Conclusions—
Deficiency of macrophage ACAT1 accelerates atherosclerosis in hypercholesterolemic apoE
−/−
mice but has no effect when the hypercholesterolemia is corrected by macrophage apoE expression. However, ACAT1 deletion impairs ABCA1-mediated cholesterol efflux in macrophages regardless of apoE expression. Changes in membrane stability, susceptibility to apoptosis, and inflammatory response may also be important in this process.
Collapse
Affiliation(s)
- Yan Ru Su
- Atherosclerosis Research Unit, Department of Medicine, Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tenn 37232-6300, USA.
| | | | | | | | | | | | | |
Collapse
|
27
|
Zhang B, Groffen J, Heisterkamp N. Resistance to farnesyltransferase inhibitors in Bcr/Abl-positive lymphoblastic leukemia by increased expression of a novel ABC transporter homolog ATP11a. Blood 2005; 106:1355-61. [PMID: 15860663 PMCID: PMC1895195 DOI: 10.1182/blood-2004-09-3655] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Resistance to cytotoxic drugs frequently emerges during treatment of leukemia with conventional chemotherapy. New classes of anticancer drugs, such as the farnesyltransferase inhibitors (FTIs), show therapeutic promise, but whether cells will easily develop resistance against them is not known. Here, we grew breakpoint cluster region/Abelson murine leukemia (Bcr/Abl) P190 lymphoblasts on stroma and made them resistant to the FTI SCH66336/lonafarnib to model emerging drug resistance in a patient. These cells exhibited greatly increased (> 100-fold) expression levels of a novel ATP (adenosine triphosphate)-binding cassette (ABC) transporter-homologous gene, ATP11A. We showed that overexpression of this gene provided protection against the effects of SCH66336, whereas knockdown of endogenous ATP11a using small interfering RNA (siRNA) made cells more sensitive to this drug. The lymphoblasts that were resistant to this FTI were also more resistant to FTI-276 and to GGTI-298, 2 other structurally similar inhibitors. Surprisingly, the cells were also able to survive higher concentrations of imatinib mesylate, the Bcr/Abl tyrosine kinase inhibitor. However, the cells remained sensitive to vincristine. Our results show that elevated levels of ATP11a can protect malignant lymphoblastic leukemia cells against several novel small molecule signal transduction inhibitors. A determination of the expression levels of this gene may have prognostic value when treatment with such classes of drugs is contemplated.
Collapse
Affiliation(s)
- Bin Zhang
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology, Ms#54, Childrens Hospital Los Angeles Saban Research Institute, 4650 Sunset Blvd, Los Angeles, CA 90027, USA
| | | | | |
Collapse
|
28
|
Ragozin S, Niemeier A, Laatsch A, Loeffler B, Merkel M, Beisiegel U, Heeren J. Knockdown of hepatic ABCA1 by RNA interference decreases plasma HDL cholesterol levels and influences postprandial lipemia in mice. Arterioscler Thromb Vasc Biol 2005; 25:1433-8. [PMID: 15845910 DOI: 10.1161/01.atv.0000166616.86723.d0] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE To investigate the impact of hepatic ABCA1 on systemic lipoprotein metabolism in vivo by an adenovirus-mediated RNA interference approach. METHODS AND RESULTS Efficiency of plasmid-based small interference RNA (siRNA)-induced knockdown of cotransfected murine ATP binding cassette transporter A1 (mABCA1) in HEK-293 cells was judged by RT-polymerase chain reaction, immunofluorescence, and Western blot analysis. The most effective plasmid was used to generate a recombinant adenovirus as a tool to selectively downregulate ABCA1 expression in mouse liver (C57BL/6). In comparison to controls, Western blot analysis from liver membrane proteins of Ad-anti-ABCA1 infected mice resulted in an approximately 50% reduction of endogenous ABCA1 and a clear upregulation of apolipoprotein E. Fast protein liquid chromatography analysis of plasma revealed that hepatic ABCA1 protein reduction was associated with an approximately 40% decrease of HDL cholesterol and a reduction of HDL-associated apolipoprotein A-I and E. In the fasted state, other lipoprotein classes were not affected. To analyze the influence of ABCA1 downregulation on postprandial lipemia, infected mice were given a gastric load of radiolabeled trioleate in olive oil. In Ad-anti-ABCA1 infected mice, the postprandial increase of chylomicrons and chylomicron-associated apolipoproteins B and E was significantly reduced as compared with controls. CONCLUSIONS Hepatic ABCA1 contributes to HDL plasma levels and influences postprandial lipemia.
Collapse
Affiliation(s)
- Sergei Ragozin
- Institute for Biochemistry and Molecular Biology II, Molecular Cell Biology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | | | | | | | | | | | | |
Collapse
|
29
|
Dove DE, Su YR, Zhang W, Jerome WG, Swift LL, Linton MF, Fazio S. ACAT1 deficiency disrupts cholesterol efflux and alters cellular morphology in macrophages. Arterioscler Thromb Vasc Biol 2004; 25:128-34. [PMID: 15499044 DOI: 10.1161/01.atv.0000148323.94021.e5] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Acyl-coenzyme A: cholesterol acyltransferase (ACAT) converts intracellular free cholesterol (FC) into cholesteryl esters (CE) for storage in lipid droplets. Recent studies in our laboratory have shown that the deletion of the macrophage ACAT1 gene results in apoptosis and increased atherosclerotic lesion area in the aortas of hyperlipidemic mice. The objective of the current study was to elucidate the mechanism of the increased atherosclerosis. METHODS AND RESULTS CE storage and FC efflux were studied in ACAT1(-/-) peritoneal macrophages that were treated with acetylated low-density lipoprotein (acLDL). Our results show that efflux of cellular cholesterol was reduced by 25% in ACAT1-deficient cells compared with wild-type controls. This decrease occurred despite the upregulated expression of ABCA1, an important mediator of cholesterol efflux. In contrast, ACAT1 deficiency increased efflux of the cholesterol derived from acLDL by 32%. ACAT1-deficient macrophages also showed a 26% increase in the accumulation of FC derived from acLDL, which was associated with a 75% increase in the number of intracellular vesicles. CONCLUSIONS Together, these data show that macrophage ACAT1 influences the efflux of both cellular and lipoprotein-derived cholesterol and propose a pathway for the pro-atherogenic transformation of ACAT1(-/-) macrophages.
Collapse
MESH Headings
- ATP Binding Cassette Transporter 1
- ATP-Binding Cassette Transporters/biosynthesis
- ATP-Binding Cassette Transporters/metabolism
- Acetyl-CoA C-Acetyltransferase
- Animals
- Biological Transport, Active/physiology
- Cholesterol/metabolism
- Cholesterol/toxicity
- Cholesterol Esters/metabolism
- Cholesterol, LDL/chemistry
- Cholesterol, LDL/metabolism
- Endosomes/chemistry
- Foam Cells/metabolism
- Lysosomes/chemistry
- Macrophages, Peritoneal/chemistry
- Macrophages, Peritoneal/enzymology
- Macrophages, Peritoneal/metabolism
- Macrophages, Peritoneal/ultrastructure
- Mice
- Microscopy, Electron, Transmission/methods
- Microscopy, Fluorescence/methods
- RNA, Messenger/metabolism
- Sterol O-Acyltransferase/deficiency
- Sterol O-Acyltransferase/physiology
- Tritium/metabolism
Collapse
Affiliation(s)
- Dwayne E Dove
- Department of Pathology, Vanderbilt University Medical Center, Nashville, Tenn 37232-6300, USA
| | | | | | | | | | | | | |
Collapse
|
30
|
Ando H, Tsuruoka S, Yamamoto H, Takamura T, Kaneko S, Fujimura A. Effects of pravastatin on the expression of ATP-binding cassette transporter A1. J Pharmacol Exp Ther 2004; 311:420-5. [PMID: 15210833 DOI: 10.1124/jpet.104.068213] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In vitro inhibition of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase causes the suppression of liver X receptor (LXR) activity. Because LXR regulates the expression of ATP-binding cassette transporter (ABC) A1, which is involved in the high-density lipoprotein-related reverse cholesterol transport pathway, we examined the effects of an HMG-CoA reductase inhibitor pravastatin on ABCA1 expression in vitro and in vivo. Pravastatin (10 microM) significantly reduced the transcript levels of murine ABCA1 gene by 35% in RAW264.7 macrophages under a lipoprotein-deficient condition. The inhibition was due to the decreased mevalonic acid production because addition of exogenous mevalonic acid restored ABCA1 mRNA levels. In addition, cholesterol and 22(R)-hydroxycholesterol thoroughly blunted the inhibition. Furthermore, pravastatin did not decrease ABCA1 mRNA and protein levels in HepG2 hepatocytes even in the absence of exogenous LXR agonists. Oral dosing of pravastatin (0.1% concentration in drinking water) for 24 h or 2 weeks to mice did not decrease ABCA1 mRNA and protein levels in the liver and leukocytes. Interestingly, pravastatin significantly increased both hepatic and leukocyte LXRalpha mRNA levels. Thus, although HMG-CoA reductase inhibitors suppress ABCA1 mRNA expression in the absence of LXR agonists, in vivo inhibition of HMG-CoA reductase is unlikely to cause such suppression.
Collapse
Affiliation(s)
- Hitoshi Ando
- Division of Clinical Pharmacology, Department of Pharmacology, Jichi Medical School, Tochigi 329-0498, Japan
| | | | | | | | | | | |
Collapse
|
31
|
Su YR, Ishiguro H, Major AS, Dove DE, Zhang W, Hasty AH, Babaev VR, Linton MF, Fazio S. Macrophage apolipoprotein A-I expression protects against atherosclerosis in ApoE-deficient mice and up-regulates ABC transporters. Mol Ther 2004; 8:576-83. [PMID: 14529830 DOI: 10.1016/s1525-0016(03)00214-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
The antiatherogenic effect of high-density lipoprotein (HDL) and its major protein component apolipoprotein A-I (apoA-I) has been largely attributed to their key roles in reverse cholesterol transport (RCT) and cellular cholesterol efflux. Substantial evidence shows that overexpression of human apoA-I reduces atherosclerosis in animal models. However, it is uncertain whether this protection is due to an increase in plasma HDL level or to a local effect in the artery wall. To test the hypothesis that expression of human apoA-I in macrophages can promote RCT in the artery wall, we used a retroviral construct expressing human apoA-I cDNA (MFG-HAI) to transduce ApoE(-/-) bone marrow cells and then transplanted these cells into ApoE(-/-) mice with preexisting atherosclerosis. ApoE(-/-) mice reconstituted with MFG-HAI marrow had a significant reduction (30%) in atherosclerotic lesions in the proximal aorta compared to control mice that received marrow expressing MFG parental virus. Peritoneal macrophages isolated from MFG-HAI mice showed a four- to fivefold increase in mRNA expression levels of both ATP-binding cassette (ABC) A1 and ABCG1 compared to controls. Our data demonstrate that gene transfer-mediated expression of human apoA-I in macrophages can compensate in part for apoE deficiency and delay the progression of atherosclerotic lesions by stimulating ABC-dependent cholesterol efflux and RCT.
Collapse
Affiliation(s)
- Yan Ru Su
- Atherosclerosis Research Unit, Division of Cardiology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232-6300, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Chen ZJ, Vulevic B, Ile KE, Soulika A, Davis W, Reiner PB, Connop BP, Nathwani P, Trojanowski JQ, Tew KD. Association of ABCA2 expression with determinants of Alzheimer's disease. FASEB J 2004; 18:1129-31. [PMID: 15155565 DOI: 10.1096/fj.03-1490fje] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
With the use of a novel method for detecting differential gene expression, alterations in functional gene clusters related to transport or oxidative stress response and beta-amyloid (Abeta) peptide metabolism were identified in a HEK293 cell line engineered to overexpress the human ATP binding cassette transporter ABCA2. These included fatty acid binding protein, phospholipid binding protein, phospholipid synthesis protein, transporter cofactors, seladin-1, Abeta precursor protein (APP), vimentin, and low-density lipoprotein receptor-related protein. ABCA2 was highly expressed in neuroblastoma cells and colocalized with Abeta and APP. Additionally, increased APP protein levels were detected within ABCA2/APP double-transfected cells, and increased Abeta was detected in the media of ABCA2-transfected cells relative to controls. The transporter was abundant in the temporal and frontal regions of both normal and Alzheimer's disease (AD) brain but was detected at lower concentrations in the parietal, occipital, and cerebellar regions. The ABCA2 transfected cell line expressed resistance to a free radical initiator, confirming involvement in protection against reactive oxygen species and suggesting a further possible link to AD.
Collapse
Affiliation(s)
- Zhijian J Chen
- Department of Pharmacology, Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Fu Y, Hoang A, Escher G, Parton RG, Krozowski Z, Sviridov D. Expression of Caveolin-1 Enhances Cholesterol Efflux in Hepatic Cells. J Biol Chem 2004; 279:14140-6. [PMID: 14729661 DOI: 10.1074/jbc.m311061200] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
HepG2 cells were stably transfected with human caveolin-1 (HepG2/cav cells). Transfection resulted in expression of caveolin-1 mRNA, a high abundance of caveolin-1 protein, and the formation of caveolae on the plasma membrane. Cholesterol efflux from HepG2/cav cells was 280 and 45% higher than that from parent HepG2 cells when human plasma and human apoA-I, respectively, were used as acceptors. The difference in efflux was eliminated by treatment of cells with progesterone. There was no difference in cholesterol efflux to cyclodextrin. Cholesterol efflux from plasma membrane vesicles was similar for the two cell types. Transfection led to a 40% increase in the amount of plasma membrane cholesterol in cholesterol-rich domains (caveolae and/or rafts) and a 67% increase in the rate of cholesterol trafficking from intracellular compartments to these domains. Cholesterol biosynthesis in HepG2/cav cells was increased by 2-fold, and cholesterol esterification was reduced by 50% compared with parent HepG2 cells. The proliferation rate of transfected cells was significantly lower than that of non-transfected cells. Transfection did not affect expression of ABCA1 or the abundance of ABCA1 protein, but decreased secretion of apoA-I. We conclude that overexpression of caveolin-1 in hepatic cells stimulates cholesterol efflux by enhancing transfer of cholesterol to cholesterol-rich domains in the plasma membrane.
Collapse
Affiliation(s)
- Ying Fu
- Wynn Domain, Baker Heart Research Institute, Melbourne, Victoria 8008, Australia
| | | | | | | | | | | |
Collapse
|
34
|
Gate L, Majumdar RS, Lunk A, Tew KD. Increased myeloproliferation in glutathione S-transferase pi-deficient mice is associated with a deregulation of JNK and Janus kinase/STAT pathways. J Biol Chem 2003; 279:8608-16. [PMID: 14684749 DOI: 10.1074/jbc.m308613200] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
It has been shown that glutathione S-transferase pi (GSTpi) interacts with and suppresses the activity of c-Jun NH(2)-terminal kinase (JNK). GST-deficient mice (GSTpi(-/-)) have higher levels of circulating white blood cells, with similar proportions of lymphocytes, monocytes, and granulocytes. Interestingly, a selective expansion of splenic B lymphocytes was observed in GSTpi(-/-) animals but no change in T lymphocytes or natural killer cells. A peptidomimetic inhibitor of GSTpi that disrupts the interaction between GSTpi and JNK mimics in wild type mice the increased myeloproliferation observed in GSTpi(-/-) animals. Until now, the molecular basis for this effect has not been defined. In an in vitro hematopoiesis assay, interleukin-3, granulocyte colony-stimulating factor, and granulocyte/macrophage colony-stimulating factor were more effective at stimulating proliferation of hematopoietic cells in GSTpi(-/-) mice than in wild type. The JNK inhibitor SP600125 which caused little inhibition of cytokine-induced myeloproliferation in wild type mice, decreased the number of colonies in GSTpi(-/-) animals. A more sustained phosphorylation of the STAT family of proteins was also observed in GSTpi(-/-) bone marrow-derived mast cells exposed to interleukin-3. This was associated with an increased proliferation and a down-regulation of expression of negative regulators of the Janus kinase-STAT pathway SHP, Src homology 2 domain-containing tyrosine phosphatase-1 and -2. The increased activation of JNK and STATs in GSTpi-deficient mice provides a viable mechanism for the increased myeloproliferation in these animals. These data also confirm the important role that GSTpi plays in the regulation of cell signaling pathways in a myeloproliferative setting.
Collapse
Affiliation(s)
- Laurent Gate
- Department of Pharmacology, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA
| | | | | | | |
Collapse
|
35
|
Zhang W, Yancey PG, Su YR, Babaev VR, Zhang Y, Fazio S, Linton MF. Inactivation of Macrophage Scavenger Receptor Class B Type I Promotes Atherosclerotic Lesion Development in Apolipoprotein E–Deficient Mice. Circulation 2003; 108:2258-63. [PMID: 14581413 DOI: 10.1161/01.cir.0000093189.97429.9d] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Scavenger receptor class B type I (SR-BI) is expressed in macrophages, where it has been proposed to facilitate cholesterol efflux. However, direct evidence that the expression of macrophage SR-BI is protective against atherosclerosis is lacking. In this study, we examined the in vivo role of macrophage SR-BI in atherosclerotic lesion development in the apolipoprotein (apo) E-deficient mouse model. METHODS AND RESULTS ApoE-deficient mice with (n=16) or without (n=15) expression of macrophage SR-BI were created by transplanting lethally irradiated apoE-deficient mice with bone marrow cells collected from SR-BI-/- apoE-/- mice or SR-BI+/+ apoE-/- mice. The recipient mice were fed a chow diet for 12 weeks after transplantation for analysis of atherosclerosis. Quantification of macrophage SR-BI mRNA by real-time reverse transcription-polymerase chain reaction indicated successful engraftment of donor bone marrow and inactivation of macrophage SR-BI in recipient mice reconstituted with SR-BI-/- apoE-/- bone marrow. There were no significant differences in plasma lipid levels, lipoprotein distributions, and HDL subpopulations between the 2 groups. Analysis of the proximal aorta demonstrated an 86% increase in mean atherosclerotic lesion area in SR-BI-/- apoE-/- --> apoE-/- mice compared with SR-BI+/+ apoE-/- --> apoE-/- mice (109.50+/-18.08 versus 58.75+/-9.58x10(3) microm2; mean+/-SEM, P=0.017). No difference in cholesterol efflux from SR-BI+/+ apoE-/- or SR-BI-/- apoE-/- macrophages to HDL or apoA-I discs was detected. CONCLUSIONS Expression of macrophage SR-BI protects mice against atherosclerotic lesion development in apoE-deficient mice in vivo without influencing plasma lipids, HDL subpopulations, or cholesterol efflux. Thus, macrophage SR-BI plays an antiatherogenic role in vivo, providing a new therapeutic target for the design of strategies to prevent and treat atherosclerosis.
Collapse
MESH Headings
- ATP Binding Cassette Transporter 1
- ATP-Binding Cassette Transporters/biosynthesis
- Animals
- Aorta/pathology
- Apolipoproteins E/deficiency
- Apolipoproteins E/genetics
- Arteriosclerosis/genetics
- Arteriosclerosis/pathology
- Blotting, Western
- Bone Marrow Transplantation
- CD36 Antigens/biosynthesis
- CD36 Antigens/genetics
- Cells, Cultured
- Cholesterol/metabolism
- Disease Models, Animal
- Disease Progression
- Female
- Lipoproteins, HDL/blood
- Macrophages, Peritoneal/metabolism
- Membrane Proteins
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Radiation Chimera
- Receptors, Immunologic
- Receptors, Lipoprotein
- Receptors, Scavenger
- Scavenger Receptors, Class B
Collapse
Affiliation(s)
- Wenwu Zhang
- Atherosclerosis Research Unit, Division of Cardiovascular Medicine, Departments of Medicine, Vanderbilt University Medical Center, Nashville, Tenn 37232-6300, USA
| | | | | | | | | | | | | |
Collapse
|
36
|
Weng S, Zemany L, Standley KN, Novack DV, La Regina M, Bernal-Mizrachi C, Coleman T, Semenkovich CF. Beta3 integrin deficiency promotes atherosclerosis and pulmonary inflammation in high-fat-fed, hyperlipidemic mice. Proc Natl Acad Sci U S A 2003; 100:6730-5. [PMID: 12746502 PMCID: PMC164515 DOI: 10.1073/pnas.1137612100] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Hyperlipidemia promotes the chronic inflammatory disease atherosclerosis through poorly understood mechanisms. Atherogenic lipoproteins activate platelets, but it is unknown whether platelets contribute to early inflammatory atherosclerotic lesions. To address the role of platelet aggregation in diet-induced vascular disease, we studied beta3 integrin-deficient mice (lacking platelet integrin alphaIIbbeta3 and the widely expressed nonplatelet integrin alphavbeta3) in two models of atherosclerosis, apolipoprotein E (apoE)-null and low-density lipoprotein receptor (LDLR)-null mice. Unexpectedly, a high-fat, Western-type (but not a low-fat) diet caused death in two-thirds of the beta3-/-apoE-/- and half of the beta3-/-LDLR-/- mice due to noninfectious pneumonitis. In animals from both models surviving high-fat feeding, pneumonitis was absent, but aortic atherosclerosis was 2- to 6-fold greater in beta3-/- compared with beta+/+ littermates. Expression of CD36, CD40L, and CD40 was increased in lungs of beta3-/-LDLR-/- mice. Each was also increased in smooth muscle cells cultured from beta3-deficient mice and suppressed by retroviral reconstitution of beta3. These data show that the platelet defect caused by alphaIIbbeta3 deficiency does not impair atherosclerotic lesion initiation. They also suggest that alphavbeta3 has a suppressive effect on inflammation, the loss of which induces atherogenic mediators that are amplified by diet-induced hyperlipidemia.
Collapse
Affiliation(s)
- Sherry Weng
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | | | | | | | | | | | | | | |
Collapse
|