1
|
Haas MJ, Parekh S, Kalidas P, Richter A, Warda F, Wong NCW, Tokuda M, Mooradian AD. Insulin mimetic effect of D-allulose on apolipoprotein A-I gene. J Food Biochem 2022; 46:e14064. [PMID: 34984676 DOI: 10.1111/jfbc.14064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/23/2021] [Accepted: 12/17/2021] [Indexed: 12/07/2022]
Abstract
Several nutrients modulate the transcriptional activity of the apolipoprotein A-I (apo A-I) gene. To determine the influence of rare sugars on apo A-I expression in hepatic (HepG2) and intestinal derived (Caco-2) cell lines, apo A-I, albumin, and SP1 were quantified with enzyme immunoassay and Western blots while mRNA levels were quantified with real-time polymerase chain reaction. The promoter activity was measured using transient transfection assays with plasmids containing various segments and mutations in the promoter. D-allulose and D-tagatose, increased apo A-I concentration in culture media while D-sorbose and D-allose did not have any measurable effects. D-allulose did not increase apo A-I levels in Caco-2 cells. These changes paralleled the increased mRNA levels and promoter activity. D-allulose-response was mapped at the insulin response core element (IRCE). Mutation of the IRCE decreased the ability of D-allulose and insulin to activate the promoter. Treatment of HepG2 cells, but not Caco-2 cells, with D-alluose and insulin increased SP1 expression relative to control cells. D-allulose augmented the expression and IRCE binding of SP1, an essential transcription factor for the insulin on apo A-I promoter activity. D-allulose can modulate some insulin-responsive genes and may have anti-atherogenic properties, in part due to increasing apo A-I production. PRACTICAL APPLICATIONS: Coronary artery disease (CAD) is the number one cause of mortality in industrialized countries. A risk factor associated with CAD is low high-density lipoprotein (HDL) cholesterol and apolipoprotein A-I (apo A-I) concentrations in plasma. Thus, novel therapeutic agents or nutrients that upregulate apo A-I production should be identified. D-allulose and D-tagatose are used as sweeteners and may have favorable effects on insulin resistance and diabetes. This study shows that D-allulose and D-tagatose increases apo A-I production through increased transcription factor SP1-binding to insulin response element of the promoter. These sweeteners modulate some insulin responsive genes, increase the production of apo-A-I, and therefore may have anti-atherogenic properties.
Collapse
Affiliation(s)
- Michael J Haas
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida College of Medicine, Jacksonville, Florida, USA
| | - Shrina Parekh
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida College of Medicine, Jacksonville, Florida, USA
| | - Poonam Kalidas
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida College of Medicine, Jacksonville, Florida, USA
| | - Angela Richter
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida College of Medicine, Jacksonville, Florida, USA
| | - Firas Warda
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida College of Medicine, Jacksonville, Florida, USA
| | | | - Masaaki Tokuda
- Department of Cell Physiology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Arshag D Mooradian
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida College of Medicine, Jacksonville, Florida, USA
| |
Collapse
|
2
|
Abstract
Earlier epidemiological studies have shown an inverse correlation between high-density lipoprotein cholesterol (HDLc) and coronary heart disease (CHD). This observation along with the finding that reverse cholesterol transport is mediated by HDL, supported the hypothesis that the HDL molecule has a cardioprotective role. More recently, epidemiological data suggest a U-shaped curve correlating HDLc and CHD. In addition, randomized clinical trials of drugs that significantly increase plasma HDLc levels, such as nicotinic acid and cholesterol ester transfer protein (CETP) inhibitors failed to show a reduction in major adverse cardiovascular events. These observations challenge the hypothesis that HDL has a cardioprotective role. It is possible that HDL quality and function is optimal only when de novo synthesis of apo A-I occurs. Inhibition of turnover of HDL with currently available agents yields HDL molecules that are ineffective in reverse cholesterol transport. To test this hypothesis, newer therapeutic drugs that increase de novo production of HDL and apo A-I should be tested in clinical trials.
Collapse
Affiliation(s)
- Julien J Feghaly
- Department of Medicine, School of Medicine, Saint Louis University, Saint Louis, MO, USA
| | - Arshag D Mooradian
- Department of Medicine, University of Florida College of Medicine, 653-1 West 8th Street, 4th Floor-LRC, Jacksonville, FL, 32209, USA.
| |
Collapse
|
3
|
Sulaiman RA. Inherited metabolic disorders and dyslipidaemia. J Clin Pathol 2019; 73:384-390. [PMID: 31757783 DOI: 10.1136/jclinpath-2019-205910] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 09/23/2019] [Accepted: 10/07/2019] [Indexed: 11/04/2022]
Abstract
Monogenic dyslipidaemia is a diverse group of multisystem disorders. Patients may present to various specialities from early childhood to late in adult life, and it usually takes longer before the diagnosis is established. Increased awareness of these disorders among clinicians is imperative for early diagnosis. This best practice review provides an overview of primary dyslipidaemias, highlighting their clinical presentation, relevant biochemical and molecular tests. It also addresses the emerging role of genetics in the early diagnosis and prevention of these disorders.
Collapse
Affiliation(s)
- Raashda A Sulaiman
- Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| |
Collapse
|
4
|
Haas MJ, Onstead-Haas L, Kurban W, Shah H, Plazarte M, Chamseddin A, Mooradian AD. High-Throughput Analysis Identifying Drugs That Regulate Apolipoprotein A-I Synthesis. Assay Drug Dev Technol 2017; 15:362-371. [DOI: 10.1089/adt.2017.782] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Michael J. Haas
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida College of Medicine—Jacksonville, Jacksonville, Florida
| | - Luisa Onstead-Haas
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida College of Medicine—Jacksonville, Jacksonville, Florida
| | - William Kurban
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida College of Medicine—Jacksonville, Jacksonville, Florida
| | - Harshit Shah
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida College of Medicine—Jacksonville, Jacksonville, Florida
| | - Monica Plazarte
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida College of Medicine—Jacksonville, Jacksonville, Florida
| | - Ayham Chamseddin
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida College of Medicine—Jacksonville, Jacksonville, Florida
| | - Arshag D. Mooradian
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida College of Medicine—Jacksonville, Jacksonville, Florida
| |
Collapse
|
5
|
Mooradian AD, Haas MJ. Targeting high-density lipoproteins: increasing de novo production versus decreasing clearance. Drugs 2016; 75:713-22. [PMID: 25895465 DOI: 10.1007/s40265-015-0390-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Although cardiovascular mortality has been decreasing in industrialized countries, there continues to be a substantial residual risk; thus, novel therapeutic agents and new targets of therapy have been sought. One highly plausible therapeutic target is high-density lipoprotein (HDL). HDL is a key player in reverse cholesterol transport and possesses a slew of other cardioprotective properties; however, recent trials with agents known to increase HDL levels have generally not shown any reduction in cardiovascular events. Further analysis of these trials suggest that fibrates have consistently reduced some cardiovascular outcomes, at least in the subgroup of patients with high serum triglycerides and low HDL cholesterol (HDLc) levels. Since fibrates, unlike niacin or cholesterol ester transfer protein inhibitors, increase HDLc level mostly through the stimulation of apolipoprotein A-I production, it is suggested that the quality and functionality of HDL are enhanced when de novo synthesis rather than inhibition of turnover is the mechanism of increasing HDL level. In this communication, the evidence for and against the cardioprotective properties of HDL is reviewed and the contemporary clinical trials are discussed.
Collapse
Affiliation(s)
- Arshag D Mooradian
- Department of Medicine, University of Florida College of Medicine, 655 West 11th Street, Jacksonville, FL, 32209, USA,
| | | |
Collapse
|
6
|
Kardassis D, Gafencu A, Zannis VI, Davalos A. Regulation of HDL genes: transcriptional, posttranscriptional, and posttranslational. Handb Exp Pharmacol 2015; 224:113-179. [PMID: 25522987 DOI: 10.1007/978-3-319-09665-0_3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
HDL regulation is exerted at multiple levels including regulation at the level of transcription initiation by transcription factors and signal transduction cascades; regulation at the posttranscriptional level by microRNAs and other noncoding RNAs which bind to the coding or noncoding regions of HDL genes regulating mRNA stability and translation; as well as regulation at the posttranslational level by protein modifications, intracellular trafficking, and degradation. The above mechanisms have drastic effects on several HDL-mediated processes including HDL biogenesis, remodeling, cholesterol efflux and uptake, as well as atheroprotective functions on the cells of the arterial wall. The emphasis is on mechanisms that operate in physiologically relevant tissues such as the liver (which accounts for 80% of the total HDL-C levels in the plasma), the macrophages, the adrenals, and the endothelium. Transcription factors that have a significant impact on HDL regulation such as hormone nuclear receptors and hepatocyte nuclear factors are extensively discussed both in terms of gene promoter recognition and regulation but also in terms of their impact on plasma HDL levels as was revealed by knockout studies. Understanding the different modes of regulation of this complex lipoprotein may provide useful insights for the development of novel HDL-raising therapies that could be used to fight against atherosclerosis which is the underlying cause of coronary heart disease.
Collapse
Affiliation(s)
- Dimitris Kardassis
- Department of Biochemistry, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology of Hellas, Heraklion, Crete, 71110, Greece,
| | | | | | | |
Collapse
|
7
|
Haas MJ, Onstead-Haas LM, Naem E, Wong NCW, Mooradian AD. Induction of apolipoprotein A-I gene expression by black seed (Nigella sativa) extracts. PHARMACEUTICAL BIOLOGY 2014; 52:1119-1127. [PMID: 24635344 DOI: 10.3109/13880209.2013.879187] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
CONTEXT Black seed [Nigella sativa L. (Ranunculaceae)] has been shown in animal models to lower serum cholesterol levels. OBJECTIVES In order to determine if extracts from black seed have any effects on high-density lipoprotein (HDL), we characterized the effects of black seed extract on apolipoprotein A-I (apo A-I) gene expression, the primary protein component of HDL. MATERIALS AND METHODS Hepatocytes (HepG2) and intestinal cells (Caco-2) were treated with black seed extracts, and Apo A-I, peroxisome proliferator-activated receptor α (PPARα), and retinoid-x-receptor α (RXRα) were measured by Western blot analysis. Apo A-I mRNA levels were measured by quantitative real-time polymerase chain reaction and apo A-I gene transcription was measured by transient transfection of apo A-I reporter plasmids. RESULTS Extracts from black seeds significantly increased hepatic and intestinal apo A-I secretion, as well as apo A-I mRNA and gene promoter activity. This effect required a PPARα binding site in the apo A-I gene promoter. Treatment of the extract with either heat or trypsin had no effect on its ability to induce apo A-I secretion. Treatment with black seed extract induced PPARα expression 9-fold and RXRα expression 2.5-fold. Furthermore, the addition of PPARα siRNA but not a control siRNA prevented some but not all the positive effects of black seed on apo A-I secretion. DISCUSSION Black seed extract is a potent inducer of apo A-I gene expression, presumably by enhancing PPARα/RXRα expression. CONCLUSIONS We conclude that black seed may have beneficial effects in treating dyslipidemia and coronary heart disease.
Collapse
Affiliation(s)
- Michael J Haas
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida , Jacksonville, FL , USA and
| | | | | | | | | |
Collapse
|
8
|
Is High-Density Lipoprotein Cardioprotective or Simply a Marker of Cardiovascular Disease? Am J Ther 2014; 21:438-9. [DOI: 10.1097/mjt.0b013e3182838e47] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
9
|
Mooradian AD, Haas MJ. The effect of nutritional supplements on serum high-density lipoprotein cholesterol and apolipoprotein A-I. Am J Cardiovasc Drugs 2014; 14:253-74. [PMID: 24604774 DOI: 10.1007/s40256-014-0068-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
One of the factors contributing to the increased risk of developing premature atherosclerosis is low plasma concentrations of high-density lipoprotein (HDL) cholesterol. Multiple potential mechanisms account for the cardioprotective effects of HDL and its main protein apolipoprotein A-I (apo A-I). Diet has an important role in modulating HDL cholesterol level. The widespread use of nutritional supplements may also alter the biology of HDL. In this review, we discuss the effect of select nutritional supplements on serum HDL cholesterol and apo A-I levels. Some nutritional supplements, such as phytosterols, soy proteins, and black seed extracts, may increase HDL cholesterol levels, while others such as cholic acid and high doses of commonly used antioxidant vitamins may downregulate HDL cholesterol levels and reduce its cardioprotection. Multiple mechanisms are involved in the regulation of HDL levels, so changes in production and clearance of HDL may have different clinical implications. The clinical relevance of the changes in HDL and apo A-I caused by nutrient supplementation needs to be tested in controlled clinical trials.
Collapse
Affiliation(s)
- Arshag D Mooradian
- Department of Medicine, University of Florida College of Medicine, 653-1 West 8th Street, 4th Floor, LRC, Jacksonville, FL, 32209, USA,
| | | |
Collapse
|
10
|
LaFramboise WA, Dhir R, Kelly LA, Petrosko P, Krill-Burger JM, Sciulli CM, Lyons-Weiler MA, Chandran UR, Lomakin A, Masterson RV, Marroquin OC, Mulukutla SR, McNamara DM. Serum protein profiles predict coronary artery disease in symptomatic patients referred for coronary angiography. BMC Med 2012; 10:157. [PMID: 23216991 PMCID: PMC3566965 DOI: 10.1186/1741-7015-10-157] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Accepted: 12/05/2012] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND More than a million diagnostic cardiac catheterizations are performed annually in the US for evaluation of coronary artery anatomy and the presence of atherosclerosis. Nearly half of these patients have no significant coronary lesions or do not require mechanical or surgical revascularization. Consequently, the ability to rule out clinically significant coronary artery disease (CAD) using low cost, low risk tests of serum biomarkers in even a small percentage of patients with normal coronary arteries could be highly beneficial. METHODS Serum from 359 symptomatic subjects referred for catheterization was interrogated for proteins involved in atherogenesis, atherosclerosis, and plaque vulnerability. Coronary angiography classified 150 patients without flow-limiting CAD who did not require percutaneous intervention (PCI) while 209 required coronary revascularization (stents, angioplasty, or coronary artery bypass graft surgery). Continuous variables were compared across the two patient groups for each analyte including calculation of false discovery rate (FDR ≤ 1%) and Q value (P value for statistical significance adjusted to ≤ 0.01). RESULTS Significant differences were detected in circulating proteins from patients requiring revascularization including increased apolipoprotein B100 (APO-B100), C-reactive protein (CRP), fibrinogen, vascular cell adhesion molecule 1 (VCAM-1), myeloperoxidase (MPO), resistin, osteopontin, interleukin (IL)-1β, IL-6, IL-10 and N-terminal fragment protein precursor brain natriuretic peptide (NT-pBNP) and decreased apolipoprotein A1 (APO-A1). Biomarker classification signatures comprising up to 5 analytes were identified using a tunable scoring function trained against 239 samples and validated with 120 additional samples. A total of 14 overlapping signatures classified patients without significant coronary disease (38% to 59% specificity) while maintaining 95% sensitivity for patients requiring revascularization. Osteopontin (14 times) and resistin (10 times) were most frequently represented among these diagnostic signatures. The most efficacious protein signature in validation studies comprised osteopontin (OPN), resistin, matrix metalloproteinase 7 (MMP7) and interferon γ (IFNγ) as a four-marker panel while the addition of either CRP or adiponectin (ACRP-30) yielded comparable results in five protein signatures. CONCLUSIONS Proteins in the serum of CAD patients predominantly reflected (1) a positive acute phase, inflammatory response and (2) alterations in lipid metabolism, transport, peroxidation and accumulation. There were surprisingly few indicators of growth factor activation or extracellular matrix remodeling in the serum of CAD patients except for elevated OPN. These data suggest that many symptomatic patients without significant CAD could be identified by a targeted multiplex serum protein test without cardiac catheterization thereby eliminating exposure to ionizing radiation and decreasing the economic burden of angiographic testing for these patients.
Collapse
Affiliation(s)
- William A LaFramboise
- University of Pittsburgh, Department of Pathology, 5230 Centre Avenue, Pittsburgh, PA 15232, USA
- University of Pittsburgh, Department of Biomedical Informatics, 5150 Centre Avenue, Pittsburgh, PA 15232, USA
| | - Rajiv Dhir
- University of Pittsburgh, Department of Pathology, 5230 Centre Avenue, Pittsburgh, PA 15232, USA
- University of Pittsburgh, Department of Biomedical Informatics, 5150 Centre Avenue, Pittsburgh, PA 15232, USA
| | - Lori A Kelly
- University of Pittsburgh, Department of Pathology, 5230 Centre Avenue, Pittsburgh, PA 15232, USA
| | - Patricia Petrosko
- University of Pittsburgh, Department of Pathology, 5230 Centre Avenue, Pittsburgh, PA 15232, USA
| | - John M Krill-Burger
- University of Pittsburgh, Department of Pathology, 5230 Centre Avenue, Pittsburgh, PA 15232, USA
| | - Christin M Sciulli
- University of Pittsburgh, Department of Pathology, 5230 Centre Avenue, Pittsburgh, PA 15232, USA
| | - Maureen A Lyons-Weiler
- University of Pittsburgh, Department of Pathology, 5230 Centre Avenue, Pittsburgh, PA 15232, USA
| | - Uma R Chandran
- University of Pittsburgh, Department of Biomedical Informatics, 5150 Centre Avenue, Pittsburgh, PA 15232, USA
| | - Aleksey Lomakin
- Materials Processing Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Oscar C Marroquin
- University of Pittsburgh, Division of Cardiology, Department of Medicine, 200 Lothrop Street, Pittsburgh, PA 15213, USA
- UPMC Heart and Vascular Institute, 200 Lothrop Street, Pittsburgh, PA 15213, USA
- University of Pittsburgh, Department of Epidemiology, Graduate School of Public Health, Pittsburgh PA, 15213, USA
| | - Suresh R Mulukutla
- University of Pittsburgh, Division of Cardiology, Department of Medicine, 200 Lothrop Street, Pittsburgh, PA 15213, USA
- UPMC Heart and Vascular Institute, 200 Lothrop Street, Pittsburgh, PA 15213, USA
- University of Pittsburgh, Department of Epidemiology, Graduate School of Public Health, Pittsburgh PA, 15213, USA
| | - Dennis M McNamara
- University of Pittsburgh, Division of Cardiology, Department of Medicine, 200 Lothrop Street, Pittsburgh, PA 15213, USA
- UPMC Heart and Vascular Institute, 200 Lothrop Street, Pittsburgh, PA 15213, USA
| |
Collapse
|
11
|
Naem E, Haas MJ, Wong NCW, Mooradian AD. Endoplasmic reticulum stress in HepG2 cells inhibits apolipoprotein A-I secretion. Life Sci 2012; 92:72-80. [PMID: 23154241 DOI: 10.1016/j.lfs.2012.11.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 10/03/2012] [Accepted: 10/30/2012] [Indexed: 10/27/2022]
Abstract
AIMS Endoplasmic reticulum (ER) stress modulates gene expression and has been implicated in causing dyslipidemias. To determine if ER stress may contribute to hypoalphalipoproteinemia through suppression of apo A-I gene expression, human hepatoma cell line Hep G2 was treated with ER stress inducers and the changes in apo A-I gene expression were compared to albumin gene expression. MAIN METHODS HepG2 cells were treated with tunicamycin (TM) and thapsigargin (TG), two potent inducers of ER stress, and apo A-I and albumin protein levels, mRNA levels, and promoter activity were measured. ER stress was measured using the ER stress-responsive alkaline phosphatase assay and by Western blot quantitation of ER stress markers such as glucose-regulated protein-78 (GRP-78), phosphorylated Jun N-terminal kinase (phospho-JNK), total JNK, phosphorylated eukaryotic initiation factor 2 alpha (phospho eIF2α), and total eIF2α. KEY FINDINGS TM and TG induced ER stress in HepG2 cells and reduced apo A-I and albumin secretion in a dose-dependent manner. Intracellular albumin levels increased in cells treated with TM and TG while intracellular apo A-I levels decreased. Albumin mRNA and albumin gene promoter activity were reduced in proportion to the decrease in albumin secreted while changes in the apo A-I mRNA levels and promoter activity were modest and did not account for the reduction in apo A-I secretion. SIGNIFICANCE These results indicate that apo A-I secretion is inhibited by ER stress possibly by affecting cellular degradation pathways. However, ER stress does not affect apo A-I secretion by regulating gene expression.
Collapse
Affiliation(s)
- Emad Naem
- The Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Florida, Jacksonville College of Medicine, Jacksonville, FL 32209, USA
| | | | | | | |
Collapse
|
12
|
Naem E, Alcalde R, Gladysz M, Mesliniene S, Jaimungal S, Sheikh-Ali M, Haas MJ, Wong NCW, Mooradian AD. Inhibition of apolipoprotein A-I gene by the aryl hydrocarbon receptor: a potential mechanism for smoking-associated hypoalphalipoproteinemia. Life Sci 2012; 91:64-9. [PMID: 22727790 DOI: 10.1016/j.lfs.2012.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 05/29/2012] [Accepted: 06/07/2012] [Indexed: 10/28/2022]
Abstract
AIMS Smokers have lower plasma concentrations of high-density lipoprotein (HDL) cholesterol and apolipoprotein A-I (apo A-I) compared with nonsmokers. To determine the molecular basis of this observation, the effect of activation of the aryl hydrocarbon receptor (AhR) on apo A-I gene expression was examined. MAIN METHODS HepG2 cells were treated with AhR receptor agonists benzo(a)pyrene (BaP) and CAY10465, and AhR receptor antagonist CAY10464 and apo A-I protein, mRNA levels and promoter activity were measured. The effect of nicotine on apo A-I protein secretion was also tested. Using a series or apo A-I gene promoter deletion constructs, a xenobiotic response element (XRE) was identified. KEY FINDINGS Treatment of HepG2 cells with the AhR receptor agonists BaP and CAY10465, inhibited apo A-I protein synthesis while nicotine, which does not bind AhR had no effect. Benzo(a)pyrene treatment also suppressed apo A-I mRNA and gene promoter activity. Treatment of HepG2 cells with the AhR receptor antagonist CAY10464 reversed the suppressive effect of BaP on apo A-I gene expression. A putative xenobiotic response element (XRE) was identified between nucleotides -325 and -186 (relative to the transcriptional start site, +1). SIGNIFICANCE These results suggest that the cigarette smoking related environmental contaminant BaP promotes hypoalphalipoproteinemia in part through activation of the hepatic AhR.
Collapse
Affiliation(s)
- Emad Naem
- Department of Medicine, University of Florida, Jacksonville College of Medicine, Jacksonville, FL, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Haas MJ, Mooradian AD. What evidence is there for the role of vitamin D and apoA-1 in atheroprotection? ACTA ACUST UNITED AC 2012. [DOI: 10.2217/clp.12.25] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
14
|
Michael DR, Ashlin TG, Buckley ML, Ramji DP. Macrophages, lipid metabolism and gene expression in atherogenesis: a therapeutic target of the future? ACTA ACUST UNITED AC 2012. [DOI: 10.2217/clp.11.73] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
|
15
|
|