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Gonet-Surówka A, Ciechacka M, Kępczyński M, Dynarowicz-Latka P. Oxysterols in Cell Viability, Phospholipidosis and Extracellular Vesicles Production in a Lung Cancer Model. Cell Biochem Biophys 2024:10.1007/s12013-024-01255-3. [PMID: 38514528 DOI: 10.1007/s12013-024-01255-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 03/13/2024] [Indexed: 03/23/2024]
Abstract
The study carried out systematic research on the influence of selected oxysterols on cells viability, phospholipidosis and the level of secreted extracellular vesicles. Three oxidized cholesterol derivatives, namely 7α-hydroxycholesterol (7α-OH), 7- ketocholesterol (7-K) and 24(S)-hydroxycholesterol (24(S)-OH) were tested in three different concentrations: 50 μM, 100 μM and 200 μM for 24 h incubation with A549 lung cancer cell line. All the studied oxysterols were found to alter cells viability. The lowest survival rate of the cells was observed after 24 h of 7-K treatment, slightly better for 7α-OH while cells incubated with 24(S)-OH had the best survival rate among the oxysterols used. 7-K increased phospholipids accumulation in cells, however, most noticeable effect was noticed for 24(S)-OH. Changes in the level of extracellular vesicles secreted in cells culture after the treatment with oxysterols were also observed. It was found that all oxysterols used increased the level of secreted vesicles, both exosomes and ectosomes. The strongest effect was noticed for 24(S)-OH. Taken together, these results suggest that 7-K is the most potent inducer of cancer cell death, while 7α-OH is slightly less potent in this respect. The lower cytotoxic effect of 24(S)-OH correlates with greater phospholipids accumulation, extracellular vesicles production and better cells survival.
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Affiliation(s)
- Agnieszka Gonet-Surówka
- Faculty of Chemistry, Department of General Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland.
| | - Mariola Ciechacka
- Faculty of Chemistry, Department of General Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Mariusz Kępczyński
- Faculty of Chemistry, Department of Physical Chemistry and Electrochemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Patrycja Dynarowicz-Latka
- Faculty of Chemistry, Department of General Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
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2
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Lecis D, Prandi FR, Barone L, Belli M, Sergi D, Longo S, Muscoli S, Romeo F, Federici M, Lerakis S, Barillà F. Beyond the Cardiovascular Effects of Glucagon-like Peptide-1 Receptor Agonists: Body Slimming and Plaque Stabilization. Are New Statins Born? Biomolecules 2023; 13:1695. [PMID: 38136567 PMCID: PMC10741698 DOI: 10.3390/biom13121695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 11/19/2023] [Accepted: 11/20/2023] [Indexed: 12/24/2023] Open
Abstract
Atherosclerosis is a chronic inflammatory disease characterized by lipid and inflammatory cell deposits in the inner layer of large- and medium-sized elastic and muscular arteries. Diabetes mellitus (DM) significantly increases the risk of cardiovascular diseases and the overall and cardiovascular mortality, and it is a pro-atherogenic factor that induces atherosclerosis development and/or accelerates its progression through a multifactorial process. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are a new class of drugs, belonging to the armamentarium to fight type 2 DM, that have shown robust reductions in atherosclerotic events and all-cause mortality in all studies. Preclinical studies have shown that GLP-1RAs play a role in the immunomodulation of atherosclerosis, affecting multiple pathways involved in plaque development and progression. In this review, we wanted to explore the translational power of such preclinical studies by analyzing the most recent clinical trials investigating the atheroprotective effect of GLP-1RAs.
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Affiliation(s)
- Dalgisio Lecis
- Division of Cardiology, Department of Systems Medicine, Tor Vergata University, 00133 Rome, Italy; (F.R.P.); (L.B.); (M.B.); (D.S.); (S.M.); (F.B.)
| | - Francesca Romana Prandi
- Division of Cardiology, Department of Systems Medicine, Tor Vergata University, 00133 Rome, Italy; (F.R.P.); (L.B.); (M.B.); (D.S.); (S.M.); (F.B.)
- Division of Cardiology, Mount Sinai Hospital, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029, USA;
| | - Lucy Barone
- Division of Cardiology, Department of Systems Medicine, Tor Vergata University, 00133 Rome, Italy; (F.R.P.); (L.B.); (M.B.); (D.S.); (S.M.); (F.B.)
| | - Martina Belli
- Division of Cardiology, Department of Systems Medicine, Tor Vergata University, 00133 Rome, Italy; (F.R.P.); (L.B.); (M.B.); (D.S.); (S.M.); (F.B.)
- Cardiovascular Imaging Unit, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Domenico Sergi
- Division of Cardiology, Department of Systems Medicine, Tor Vergata University, 00133 Rome, Italy; (F.R.P.); (L.B.); (M.B.); (D.S.); (S.M.); (F.B.)
| | - Susanna Longo
- Department of Systems Medicine, Tor Vergata University, 00133 Rome, Italy; (S.L.); (M.F.)
| | - Saverio Muscoli
- Division of Cardiology, Department of Systems Medicine, Tor Vergata University, 00133 Rome, Italy; (F.R.P.); (L.B.); (M.B.); (D.S.); (S.M.); (F.B.)
| | - Francesco Romeo
- Faculty of Medicine, UniCamillus-Saint Camillus International University of Health and Medical Sciences, 00131 Rome, Italy;
| | - Massimo Federici
- Department of Systems Medicine, Tor Vergata University, 00133 Rome, Italy; (S.L.); (M.F.)
| | - Stamatios Lerakis
- Division of Cardiology, Mount Sinai Hospital, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029, USA;
| | - Francesco Barillà
- Division of Cardiology, Department of Systems Medicine, Tor Vergata University, 00133 Rome, Italy; (F.R.P.); (L.B.); (M.B.); (D.S.); (S.M.); (F.B.)
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7-Ketocholesterol Induces Lipid Metabolic Reprogramming and Enhances Cholesterol Ester Accumulation in Cardiac Cells. Cells 2021; 10:cells10123597. [PMID: 34944104 PMCID: PMC8700522 DOI: 10.3390/cells10123597] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 12/12/2021] [Accepted: 12/17/2021] [Indexed: 12/28/2022] Open
Abstract
7-Ketocholesterol (7KCh) is a major oxidized cholesterol product abundant in lipoprotein deposits and atherosclerotic plaques. Our previous study has shown that 7KCh accumulates in erythrocytes of heart failure patients, and further investigation centered on how 7KCh may affect metabolism in cardiomyocytes. We applied metabolomics to study the metabolic changes in cardiac cell line HL-1 after treatment with 7KCh. Mevalonic acid (MVA) pathway-derived metabolites, such as farnesyl-pyrophosphate and geranylgeranyl-pyrophosphate, phospholipids, and triacylglycerols levels significantly declined, while the levels of lysophospholipids, such as lysophosphatidylcholines (lysoPCs) and lysophosphatidylethanolamines (lysoPEs), considerably increased in 7KCh-treated cells. Furthermore, the cholesterol content showed no significant change, but the production of cholesteryl esters was enhanced in the treated cells. To explore the possible mechanisms, we applied mRNA-sequencing (mRNA-seq) to study genes differentially expressed in 7KCh-treated cells. The transcriptomic analysis revealed that genes involved in lipid metabolic processes, including MVA biosynthesis and cholesterol transport and esterification, were differentially expressed in treated cells. Integrated analysis of both metabolomic and transcriptomic data suggests that 7KCh induces cholesteryl ester accumulation and reprogramming of lipid metabolism through altered transcription of such genes as sterol O-acyltransferase- and phospholipase A2-encoding genes. The 7KCh-induced reprogramming of lipid metabolism in cardiac cells may be implicated in the pathogenesis of cardiovascular diseases.
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Anderson AM, Kirtadze T, Malanga M, Dinh D, Barnes C, Campo A, Clemens DM, Garcia-Fandiño R, Piñeiro Á, O'Connor MS. Cyclodextrin dimers: A versatile approach to optimizing encapsulation and their application to therapeutic extraction of toxic oxysterols. Int J Pharm 2021; 606:120522. [PMID: 33839224 DOI: 10.1016/j.ijpharm.2021.120522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 03/17/2021] [Accepted: 03/21/2021] [Indexed: 12/13/2022]
Abstract
We have developed a novel class of specifically engineered, dimerized cyclodextrin (CD) nanostructures for the encapsulation of toxic biomolecules such as 7-ketocholesterol (7KC). 7KC accumulates over time and causes dysfunction in many cell types, linking it to several age-related diseases including atherosclerosis and age-related macular degeneration (AMD). Presently, treatments for these diseases are invasive, expensive, and show limited benefits. CDs are cyclic glucose oligomers utilized to capture small, hydrophobic molecules. Here, a combination of in silico, in vitro, and ex vivo methods is used to implement a synergistic rational drug design strategy for developing CDs to remove atherogenic 7KC from cells and tissues. Mechanisms by which CDs encapsulate sterols are discussed, and we conclude that covalently linked head-to-head dimers of βCDs have substantially improved affinity for 7KC compared to monomers. We find that inclusion complexes can be stabilized or destabilized in ways that allow the design of CD dimers with increased 7KC selectivity while maintaining an excellent safety profile. These CD dimers are being developed as therapeutics to treat atherosclerosis and other debilitating diseases of aging.
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Affiliation(s)
- Amelia M Anderson
- Underdog Pharmaceuticals Inc., 110 Pioneer Way, Suite J, Mountain View, CA 94041, USA; SENS Research Foundation, 110 Pioneer Way, Suite J, Mountain View, CA, USA
| | - Tamari Kirtadze
- Underdog Pharmaceuticals Inc., 110 Pioneer Way, Suite J, Mountain View, CA 94041, USA
| | - Milo Malanga
- Cyclolab Cyclodextrin Research and Development Ltd., Budapest, Illatos út 7 1097, Hungary
| | - Darren Dinh
- Underdog Pharmaceuticals Inc., 110 Pioneer Way, Suite J, Mountain View, CA 94041, USA
| | - Carolyn Barnes
- SENS Research Foundation, 110 Pioneer Way, Suite J, Mountain View, CA, USA
| | - Angielyn Campo
- SENS Research Foundation, 110 Pioneer Way, Suite J, Mountain View, CA, USA
| | - Daniel M Clemens
- Underdog Pharmaceuticals Inc., 110 Pioneer Way, Suite J, Mountain View, CA 94041, USA
| | - Rebeca Garcia-Fandiño
- Underdog Pharmaceuticals Inc., 110 Pioneer Way, Suite J, Mountain View, CA 94041, USA; MD.USE Innovative Solutions S.L., Edificio Emprendia, Campus Vida, 15782 Santiago de Compostela (A Coruña), Spain; Centro Singular de Investigación en Química Biolóxica e, Materiais Moleculares (CIQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Ángel Piñeiro
- Underdog Pharmaceuticals Inc., 110 Pioneer Way, Suite J, Mountain View, CA 94041, USA; MD.USE Innovative Solutions S.L., Edificio Emprendia, Campus Vida, 15782 Santiago de Compostela (A Coruña), Spain; Departamento de Física Aplicada, Facultade de Física, Universidade de Santiago de Compostela, Spain
| | - Matthew S O'Connor
- Underdog Pharmaceuticals Inc., 110 Pioneer Way, Suite J, Mountain View, CA 94041, USA; SENS Research Foundation, 110 Pioneer Way, Suite J, Mountain View, CA, USA.
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Abe A, Hiraoka M, Matsuzawa F, Aikawa SI, Niimura Y. Esterification of side-chain oxysterols by lysosomal phospholipase A2. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158787. [PMID: 32777483 DOI: 10.1016/j.bbalip.2020.158787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/15/2020] [Accepted: 08/02/2020] [Indexed: 11/30/2022]
Abstract
Side-chain oxysterols produced from cholesterol either enzymatically or non-enzymatically show various bioactivities. Lecithin-cholesterol acyltransferase (LCAT) esterifies the C3-hydroxyl group of these sterols as well as cholesterol. Lysosomal phospholipase A2 (LPLA2) is related to LCAT but does not catalyze esterification of cholesterol. First, esterification of side-chain oxysterols by LPLA2 was investigated using recombinant mouse LPLA2 and dioleoyl-PC/sulfatide/oxysterol liposomes under acidic conditions. TLC and LC-MS/MS showed that the C3 and C27-hydroxyl groups of 27-hydroxycholesterol could be individually esterified by LPLA2 to form a monoester with the C27-hydroxyl preference. Cholesterol did not inhibit this reaction. Also, LPLA2 esterified other side-chain oxysterols. Their esterifications by mouse serum containing LCAT supported the idea that their esterifications by LPLA2 occur at the C3-hydroxyl group. N-acetylsphingosine (NAS) acting as an acyl acceptor in LPLA2 transacylation inhibited the side-chain oxysterol esterification by LPLA2. This suggests a competition between hydroxycholesterol and NAS on the acyl-LPLA2 intermediate formed during the reaction. Raising cationic amphiphilic drug concentration or ionic strength in the reaction mixture evoked a reduction of the side-chain oxysterol esterification by LPLA2. This indicates that the esterification could progress via an interfacial interaction of LPLA2 with the lipid membrane surface through an electrostatic interaction. The docking model of acyl-LPLA2 intermediate and side-chain oxysterol provided new insight to elucidate the transacylation mechanism of sterols by LPLA2. Finally, exogenous 25-hydroxycholesterol esterification within alveolar macrophages prepared from wild-type mice was significantly higher than that from LPLA2 deficient mice. This suggests that there is an esterification pathway of side-chain oxysterols via LPLA2.
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Affiliation(s)
- Akira Abe
- Department of Molecular Science of Bacteria, Tokyo University of Agriculture, Tokyo, Japan.
| | - Miki Hiraoka
- Department of Ophthalmology, Health Science University of Hokkaido, Sapporo, Japan
| | | | | | - Youichi Niimura
- Department of Molecular Science of Bacteria, Tokyo University of Agriculture, Tokyo, Japan
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Anderson A, Campo A, Fulton E, Corwin A, Jerome WG, O'Connor MS. 7-Ketocholesterol in disease and aging. Redox Biol 2020; 29:101380. [PMID: 31926618 PMCID: PMC6926354 DOI: 10.1016/j.redox.2019.101380] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/06/2019] [Accepted: 11/10/2019] [Indexed: 02/08/2023] Open
Abstract
7-Ketocholesterol (7KC) is a toxic oxysterol that is associated with many diseases and disabilities of aging, as well as several orphan diseases. 7KC is the most common product of a reaction between cholesterol and oxygen radicals and is the most concentrated oxysterol found in the blood and arterial plaques of coronary artery disease patients as well as various other disease tissues and cell types. Unlike cholesterol, 7KC consistently shows cytotoxicity to cells and its physiological function in humans or other complex organisms is unknown. Oxysterols, particularly 7KC, have also been shown to diffuse through membranes where they affect receptor and enzymatic function. Here, we will explore the known and proposed mechanisms of pathologies that are associated with 7KC, as well speculate about the future of 7KC as a diagnostic and therapeutic target in medicine.
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7
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Pariente A, Peláez R, Pérez-Sala Á, Larráyoz IM. Inflammatory and cell death mechanisms induced by 7-ketocholesterol in the retina. Implications for age-related macular degeneration. Exp Eye Res 2019; 187:107746. [DOI: 10.1016/j.exer.2019.107746] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 07/25/2019] [Accepted: 07/25/2019] [Indexed: 12/16/2022]
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8
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Urano Y, Ho Vo DK, Hirofumi A, Noguchi N. 24( S)-Hydroxycholesterol induces ER dysfunction-mediated unconventional cell death. Cell Death Discov 2019; 5:113. [PMID: 31285856 PMCID: PMC6611791 DOI: 10.1038/s41420-019-0192-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 05/20/2019] [Accepted: 05/30/2019] [Indexed: 02/06/2023] Open
Abstract
Endoplasmic reticulum (ER) stress induced by disruption of protein folding activates the unfolded protein response (UPR), which while generally pro-survival in effect can also induce cell death under severe ER stress. 24(S)-hydroxycholesterol (24S-OHC), which is enzymatically produced in the ER of neurons, plays an important role in maintaining brain cholesterol homeostasis but also shows neurotoxicity when subjected to esterification by acyl-CoA:cholesterol acyltransferase 1 (ACAT1) in the ER. In this study, we demonstrated that the accumulation of 24S-OHC esters in human neuroblastoma SH-SY5Y cells evoked the UPR with substantially no pro-survival adaptive response but with significant activation of pro-death UPR signaling via regulated IRE1-dependent decay (RIDD). We further found that accumulation of 24S-OHC esters caused disruption of ER membrane integrity and release of ER luminal proteins into cytosol. We also found that de novo synthesis of global proteins was robustly suppressed in 24S-OHC-treated cells. Collectively, these results show that ER dysfunction and the accompanying RIDD-mediated pro-death UPR signaling and global protein synthesis inhibition are responsible for 24S-OHC ester-induced unconventional cell death.
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Affiliation(s)
- Yasuomi Urano
- Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyoto, 610-0394 Japan
| | - Diep-Khanh Ho Vo
- Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyoto, 610-0394 Japan
| | - Araki Hirofumi
- Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyoto, 610-0394 Japan
| | - Noriko Noguchi
- Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyoto, 610-0394 Japan
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Qiao Y, Guo D, Meng L, Liu Q, Liu X, Tang C, Yi G, Wang Z, Yin W, Tian G, Yuan Z. Oxidized-low density lipoprotein accumulates cholesterol esters via the PKCα-adipophilin-ACAT1 pathway in RAW264.7 cells. Mol Med Rep 2015; 12:3599-3606. [PMID: 26017812 DOI: 10.3892/mmr.2015.3864] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 04/30/2015] [Indexed: 11/06/2022] Open
Abstract
Oxidized low‑density lipoprotein (ox‑LDL) can increase the expression of adipophilin and the accumulation of intracellular lipid droplets. However, the detailed mechanisms remain to be fully elucidated. The present study aimed to investigate the mechanism underlying the effect of ox‑LDL on the expression of adipophilin and the accumulation of intracellular cholesterol esters. The results revealed that ox‑LDL increased the activation of protein kinase C α (PKCα), expression of adipophilin and acyl‑coenzymeA: cholesterol acyltransferse 1 (ACAT1) and increased accumulation of intracellular cholesterol esters. In addition, PKCα siRNA abrogated ox‑LDL‑induced adipophilin, expression of ATAC1 and accumulation of cholesterol esters. Furthermore, ox‑LDL increased the accumulation of intracellular cholesterol esters and expression of ACAT1, and this effect were reversed by transfection with adipophilin siRNA. Taken together, these results demonstrated that ox‑LDL induces the accumulation of cholesterol esters, which is mediated by the PKCα‑adipophilin‑ACAT1 pathway.
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Affiliation(s)
- Yuncheng Qiao
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan, University of South China, Hengyang, Hunan 421001, P.R. China
| | - Dongming Guo
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan, University of South China, Hengyang, Hunan 421001, P.R. China
| | - Lei Meng
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan, University of South China, Hengyang, Hunan 421001, P.R. China
| | - Qingnan Liu
- Department of Basic Nursing, Yiyang Medical College, Yiyang, Hunan 413000, P.R. China
| | - Xiaohui Liu
- Cyrus Tang Hematology Center (Research Partnership), Jiangsu Institute of Hematology, The First Affiliated Hospital, Soochow University, Suzhou, Jiangsu 215400, P.R. China
| | - Chaoke Tang
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan, University of South China, Hengyang, Hunan 421001, P.R. China
| | - Guanghui Yi
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan, University of South China, Hengyang, Hunan 421001, P.R. China
| | - Zuo Wang
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan, University of South China, Hengyang, Hunan 421001, P.R. China
| | - Weidong Yin
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan, University of South China, Hengyang, Hunan 421001, P.R. China
| | - Guoping Tian
- Department of Cardiovascular Medicine, The Second Affiliated Hospital, University of South China, Hengyang, Hunan 421001, P.R. China
| | - Zhonghua Yuan
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan, University of South China, Hengyang, Hunan 421001, P.R. China
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Rogers MA, Liu J, Song BL, Li BL, Chang CCY, Chang TY. Acyl-CoA:cholesterol acyltransferases (ACATs/SOATs): Enzymes with multiple sterols as substrates and as activators. J Steroid Biochem Mol Biol 2015; 151:102-7. [PMID: 25218443 PMCID: PMC4851438 DOI: 10.1016/j.jsbmb.2014.09.008] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 08/13/2014] [Accepted: 09/06/2014] [Indexed: 01/18/2023]
Abstract
Cholesterol is essential to the growth and viability of cells. The metabolites of cholesterol include: steroids, oxysterols, and bile acids, all of which play important physiological functions. Cholesterol and its metabolites have been implicated in the pathogenesis of multiple human diseases, including: atherosclerosis, cancer, neurodegenerative diseases, and diabetes. Thus, understanding how cells maintain the homeostasis of cholesterol and its metabolites is an important area of study. Acyl-coenzyme A:cholesterol acyltransferases (ACATs, also abbreviated as SOATs) converts cholesterol to cholesteryl esters and play key roles in the regulation of cellular cholesterol homeostasis. ACATs are most unusual enzymes because (i) they metabolize diverse substrates including both sterols and certain steroids; (ii) they contain two different binding sites for steroidal molecules. In mammals, there are two ACAT genes that encode two different enzymes, ACAT1 and ACAT2. Both are allosteric enzymes that can be activated by a variety of sterols. In addition to cholesterol, other sterols that possess the 3-beta OH at C-3, including PREG, oxysterols (such as 24(S)-hydroxycholesterol and 27-hydroxycholesterol, etc.), and various plant sterols, could all be ACAT substrates. All sterols that possess the iso-octyl side chain including cholesterol, oxysterols, various plant sterols could all be activators of ACAT. PREG can only be an ACAT substrate because it lacks the iso-octyl side chain required to be an ACAT activator. The unnatural cholesterol analogs epi-cholesterol (with 3-alpha OH in steroid ring B) and ent-cholesterol (the mirror image of cholesterol) contain the iso-octyl side chain but do not have the 3-beta OH at C-3. Thus, they can only serve as activators and cannot serve as substrates. Thus, within the ACAT holoenzyme, there are site(s) that bind sterol as substrate and site(s) that bind sterol as activator; these sites are distinct from each other. These features form the basis to further pursue ACAT structure-function analysis, and can be explored to develop novel allosteric ACAT inhibitors for therapeutic purposes. This article is part of a Special Issue entitled 'Steroid/Sterol signaling'.
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Affiliation(s)
- Maximillian A Rogers
- Department of Biochemistry, Geisel School of Medicine, Dartmouth HB7200, Hanover, NH 03755, United States; Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Jay Liu
- Department of Biochemistry, Geisel School of Medicine, Dartmouth HB7200, Hanover, NH 03755, United States
| | - Bao-Liang Song
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Bo-Liang Li
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Catherine C Y Chang
- Department of Biochemistry, Geisel School of Medicine, Dartmouth HB7200, Hanover, NH 03755, United States.
| | - Ta-Yuan Chang
- Department of Biochemistry, Geisel School of Medicine, Dartmouth HB7200, Hanover, NH 03755, United States.
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11
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Lee JW, Huang JD, Rodriguez IR. Extra-hepatic metabolism of 7-ketocholesterol occurs by esterification to fatty acids via cPLA2α and SOAT1 followed by selective efflux to HDL. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:605-19. [PMID: 25617738 DOI: 10.1016/j.bbalip.2015.01.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 12/24/2014] [Accepted: 01/15/2015] [Indexed: 12/31/2022]
Abstract
Accumulation of 7-ketocholesterol (7KCh) in tissues has been previously associated with various chronic aging diseases. Orally ingested 7KCh is readily metabolized by the liver and does not pose a toxicity threat. However, 7KCh formed in situ, usually associated with lipoprotein deposits, can adversely affect surrounding tissues by causing inflammation and cytotoxicity. In this study we have investigated various mechanisms for extra-hepatic metabolism of 7KCh (e.g. hydroxylation, sulfation) and found only esterification to fatty acids. The esterification of 7KCh to fatty acids involves the combined action of cytosolic phospholipase A2 alpha (cPLA2α) and sterol O-acyltransferase (SOAT1). Inhibition of either one of these enzymes ablates 7KCh-fatty acid ester (7KFAE) formation. The 7KFAEs are not toxic and do not induce inflammatory responses. However, they can be unstable and re-release 7KCh. The higher the degree of unsaturation, the more unstable the 7KFAE (e.g. 18:0>18:1>18:2>18:3≫20:4). Biochemical inhibition and siRNA knockdown of SOAT1 and cPLA2α ablated the 7KFAE synthesis in cultured ARPE19 cells, but had little effect on the 7KCh-induced inflammatory response. Overexpression of SOAT1 reduced the 7KCh-induced inflammatory response and provided some protection from cell death. This effect is likely due to the increased conversion of 7KCh to 7KFAEs, which reduced the intracellular 7KCh levels. Addition of HDL selectively increased the efflux of 7KFAEs and enhanced the effect of SOAT1 overexpression. Our data suggests an additional function for HDL in aiding extra-hepatic tissues to eliminate 7KCh by returning 7KFAEs to the liver for bile acid formation.
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Affiliation(s)
- Jung Wha Lee
- Mechanisms of Retinal Diseases Section, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD, USA.
| | - Jiahn-Dar Huang
- Mechanisms of Retinal Diseases Section, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ignacio R Rodriguez
- Mechanisms of Retinal Diseases Section, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
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Sekiya M, Yamamuro D, Ohshiro T, Honda A, Takahashi M, Kumagai M, Sakai K, Nagashima S, Tomoda H, Igarashi M, Okazaki H, Yagyu H, Osuga JI, Ishibashi S. Absence of Nceh1 augments 25-hydroxycholesterol-induced ER stress and apoptosis in macrophages. J Lipid Res 2014; 55:2082-92. [PMID: 24891333 DOI: 10.1194/jlr.m050864] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
An excess of cholesterol and/or oxysterols induces apoptosis in macrophages, contributing to the development of advanced atherosclerotic lesions. In foam cells, these sterols are stored in esterified forms, which are hydrolyzed by two enzymes: neutral cholesterol ester hydrolase 1 (Nceh1) and hormone-sensitive lipase (Lipe). A deficiency in either enzyme leads to accelerated growth of atherosclerotic lesions in mice. However, it is poorly understood how the esterification and hydrolysis of sterols are linked to apoptosis. Remarkably, Nceh1-deficient thioglycollate-elicited peritoneal macrophages (TGEMs), but not Lipe-deficient TGEMs, were more susceptible to apoptosis induced by oxysterols, particularly 25-hydroxycholesterol (25-HC), and incubation with 25-HC caused massive accumulation of 25-HC ester in the endoplasmic reticulum (ER) due to its defective hydrolysis, thereby activating ER stress signaling such as induction of CCAAT/enhancer-binding protein-homologous protein (CHOP). These changes were nearly reversed by inhibition of ACAT1. In conclusion, deficiency of Nceh1 augments 25-HC-induced ER stress and subsequent apoptosis in TGEMs. In addition to reducing the cholesteryl ester content of foam cells, Nceh1 may protect against the pro-apoptotic effect of oxysterols and modulate the development of atherosclerosis.
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Affiliation(s)
- Motohiro Sekiya
- Departments of Diabetes and Metabolic Diseases, University of Tokyo, Tokyo 113-8655, Japan
| | - Daisuke Yamamuro
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi 329-0498, Japan
| | - Taichi Ohshiro
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi 329-0498, Japan
| | - Akira Honda
- Joint Research Center, Tokyo Medical University Ibaraki Medical Center, Ibaraki 300-0395, Japan
| | - Manabu Takahashi
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi 329-0498, Japan
| | - Masayoshi Kumagai
- Departments of Diabetes and Metabolic Diseases, University of Tokyo, Tokyo 113-8655, Japan
| | - Kent Sakai
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi 329-0498, Japan
| | - Shuichi Nagashima
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi 329-0498, Japan
| | - Hiroshi Tomoda
- Department of Microbial Chemistry, Graduate School of Pharmaceutical Sciences, Kitasato University, Tokyo 108-8641, Japan
| | - Masaki Igarashi
- Departments of Diabetes and Metabolic Diseases, University of Tokyo, Tokyo 113-8655, Japan
| | - Hiroaki Okazaki
- Departments of Diabetes and Metabolic Diseases, University of Tokyo, Tokyo 113-8655, Japan
| | - Hiroaki Yagyu
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi 329-0498, Japan
| | - Jun-ichi Osuga
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi 329-0498, Japan
| | - Shun Ishibashi
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi 329-0498, Japan
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Maeda T, Takeuchi K, Xiaoling P, P Zankov D, Takashima N, Fujiyoshi A, Kadowaki T, Miura K, Ueshima H, Ogita H. Lipoprotein-associated phospholipase A2 regulates macrophage apoptosis via the Akt and caspase-7 pathways. J Atheroscler Thromb 2014; 21:839-53. [PMID: 24717759 DOI: 10.5551/jat.21386] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
AIM Mutations in lipoprotein-associated phospholipase A2 (Lp-PLA2) are related to atherosclerosis. However, the molecular effects of Lp-PLA2 on atherosclerosis have not been fully investigated. Therefore, this study attempted to elucidate this issue. METHODS Monocytes were isolated from randomly selected healthy male volunteers according to each Lp-PLA2 genotype (wild-type Lp-PLA2 [Lp-PLA2 (V/V)], the heterozygous V279F mutation [LpPLA2 (V/F)] and the homozygous V279F mutation [Lp-PLA2 (F/F)]) and differentiated into macrophages. The level of apoptosis in the macrophages following incubation without serum was measured using the annexin V/propidium iodide double staining method, and the underlying mechanisms were further examined using a culture cell line. RESULTS The average plasma Lp-PLA2 concentration [Lp-PLA2 (V/V): 129.4 ng/mL, Lp-PLA2 (V/F): 70.7 ng/mL, Lp-PLA2 (F/F): 0.4 ng/mL] and activity [Lp-PLA2 (V/V): 164.3 nmol/min/mL, LpPLA2 (V/F): 100.9 nmol/min/mL, Lp-PLA2 (F/F): 11.6 nmol/min/mL] were significantly different between each genotype, although the basic clinical characteristics were similar. The percentage of apoptotic cells was significantly higher among the Lp-PLA2 (F/F) macrophages compared with that observed in the Lp-PLA2 (V/V) macrophages. This induction of apoptosis was independent of the actions of acetylated low-density lipoproteins. In addition, the transfection of the expression plasmid of V279F mutant Lp-PLA2 into Cos-7 cells or monocyte/macrophage-like U937 cells promoted apoptosis. The knockdown of Lp-PLA2 also increased the number of apoptotic cells. Among the cells expressing mutant Lp-PLA2, the caspase-7 activity was increased, while the activated Akt level was decreased. CONCLUSIONS The V279F mutation of Lp-PLA2 positively regulates the induction of apoptosis in macrophages and Cos-7 cells. An increase in the caspase-7 activity and a reduction in the activated Akt level are likely to be involved in this phenomenon.
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Affiliation(s)
- Toshinaga Maeda
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science
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14
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Afonso MDS, Castilho G, Lavrador MSF, Passarelli M, Nakandakare ER, Lottenberg SA, Lottenberg AM. The impact of dietary fatty acids on macrophage cholesterol homeostasis. J Nutr Biochem 2014; 25:95-103. [DOI: 10.1016/j.jnutbio.2013.10.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2013] [Revised: 09/11/2013] [Accepted: 10/03/2013] [Indexed: 11/16/2022]
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15
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Induction of apoptosis and necroptosis by 24(S)-hydroxycholesterol is dependent on activity of acyl-CoA:cholesterol acyltransferase 1. Cell Death Dis 2014; 5:e990. [PMID: 24407243 PMCID: PMC4040651 DOI: 10.1038/cddis.2013.524] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 11/18/2013] [Accepted: 11/25/2013] [Indexed: 02/08/2023]
Abstract
24(S)-hydroxycholesterol (24S-OHC), which is enzymatically produced in the brain, has an important role in maintaining brain cholesterol homeostasis. We have previously reported that 24S-OHC induces necroptosis in human neuroblastoma SH-SY5Y cells. In the present study, we investigated the mechanisms by which 24S-OHC-induced cell death occurs. We found that lipid droplets formed at the early stages in the treatment of SH-SY5Y cells with 24S-OHC. These lipid droplets could be almost completely eliminated by treatment with a specific inhibitor or by siRNA knockdown of acyl-CoA:cholesterol acyltransferase 1 (ACAT1). In association with disappearance of lipid droplets, cell viability was recovered by treatment with the inhibitor or siRNA for ACAT1. Using gas chromatography–mass spectrometry, we confirmed that 24S-OHC-treated cells exhibited accumulation of 24S-OHC esters but not of cholesteryl esters and confirmed that accumulation of 24S-OHC esters was reduced when ACAT1 was inhibited. 24S-OHC induced apoptosis in T-lymphoma Jurkat cells, which endogenously expressed caspase-8, but did not induce apoptosis in SH-SY5Y cells, which expressed no caspase-8. In Jurkat cells treated with the pan-caspase inhibitor ZVAD and in caspase-8-deficient Jurkat cells, 24S-OHC was found to induce caspase-independent cell death, and this was partially but significantly inhibited by Necrostatin-1. Similarly, knockdown of receptor-interacting protein kinase 3, which is one of the essential kinases for necroptosis, significantly suppressed 24S-OHC-induced cell death in Jurkat cells treated with ZVAD. These results suggest that 24S-OHC can induce apoptosis or necroptosis, which of the two is induced being determined by caspase activity. Regardless of the presence or absence of ZVAD, 24S-OHC treatment induced the formation of lipid droplets and cell death in Jurkat cells, and this was suppressed by treatment with ACAT1 inhibitor. Collectively, these results suggest that it is ACAT1-catalyzed 24S-OHC esterification and the resulting lipid droplet formation that is the initial key event which is responsible for 24S-OHC-induced cell death.
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16
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de Weille J, Fabre C, Bakalara N. Oxysterols in cancer cell proliferation and death. Biochem Pharmacol 2013; 86:154-60. [PMID: 23500545 DOI: 10.1016/j.bcp.2013.02.029] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Revised: 02/27/2013] [Accepted: 02/27/2013] [Indexed: 12/21/2022]
Abstract
Oxysterols have been shown to interfere with proliferation and cause the death of many cancer cell types, such as leukaemia, glioblastoma, colon, breast and prostate cancer cells, while they have little or no effect on senescent cells. The mechanisms by which oxysterols may influence proliferation are manifold: they control the transcription and the turnover of the key enzyme in cholesterol synthesis, 3-hydroxy-3-methylglutaryl CoA reductase, by binding to Insig-1, Insig-2 and liver X receptors. Oxysterols are thought to be generated in proportion to the rate of cholesterol synthesis. Although there is no consensus about the mechanism by which these oxysterols are generated in vivo, it clearly has to be ubiquitous. The 25- and the 27-cholesterol hydroxylases, present in almost all tissues, are possible candidates. Cholesterol uptake from lipoproteins, intracellular vesicle transport and lipid transfer are also modified by oxysterols. Oxysterols interfere with ERK, hedgehog and wnt pathways of proliferation and differentiation. When administered in vitro to cancer cell lines, oxysterols invariably both slow down proliferation and provoke cell death. Perhaps is it sufficient to stop proliferation of a cancer to provoke its eradication. Therefore, the two facets of oxysterol action that seem important for cancer treatment, cytostaticity and cytotoxicity, will be discussed.
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Affiliation(s)
- Jan de Weille
- Institut des Neurosciences de Montpellier, U1051 INSERM, 80 rue Augustin Fliche, 34295 Montpellier Cedex 05, France.
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17
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Mitić T, Shave S, Semjonous N, McNae I, Cobice DF, Lavery GG, Webster SP, Hadoke PWF, Walker BR, Andrew R. 11β-Hydroxysteroid dehydrogenase type 1 contributes to the balance between 7-keto- and 7-hydroxy-oxysterols in vivo. Biochem Pharmacol 2013; 86:146-53. [PMID: 23415904 PMCID: PMC3694296 DOI: 10.1016/j.bcp.2013.02.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 02/01/2013] [Accepted: 02/04/2013] [Indexed: 01/19/2023]
Abstract
11β-Hydroxysteroid dehydrogenase 1 (11βHSD1; EC 1.1.1.146) generates active glucocorticoids from inert 11-keto metabolites. However, it can also metabolize alternative substrates, including 7β-hydroxy- and 7-keto-cholesterol (7βOHC, 7KC). This has been demonstrated in vitro but its consequences in vivo are uncertain. We used genetically modified mice to investigate the contribution of 11βHSD1 to the balance of circulating levels of 7KC and 7βOHC in vivo, and dissected in vitro the kinetics of the interactions between oxysterols and glucocorticoids for metabolism by the mouse enzyme. Circulating levels of 7KC and 7βOHC in mice were 91.3 ± 22.3 and 22.6 ± 5.7 nM respectively, increasing to 1240 ± 220 and 406 ± 39 nM in ApoE−/− mice receiving atherogenic western diet. Disruption of 11βHSD1 in mice increased (p < 0.05) the 7KC/7βOHC ratio in plasma (by 20%) and also in isolated microsomes (2 fold). The 7KC/7βOHC ratio was similarly increased when NADPH generation was restricted by disruption of hexose-6-phosphate dehydrogenase. Reduction and oxidation of 7-oxysterols by murine 11βHSD1 proceeded more slowly and substrate affinity was lower than for glucocorticoids. in vitro 7βOHC was a competitive inhibitor of oxidation of corticosterone (Ki = 0.9 μM), whereas 7KC only weakly inhibited reduction of 11-dehydrocorticosterone. However, supplementation of 7-oxysterols in cultured cells, secondary to cholesterol loading, preferentially slowed reduction of glucocorticoids, rather than oxidation. Thus, in mouse, 11βHSD1 influenced the abundance and balance of circulating and tissue levels of 7βOHC and 7KC, promoting reduction of 7KC. In health, 7-oxysterols are unlikely to regulate glucocorticoid metabolism. However, in hyperlipidaemia, 7-oxysterols may inhibit glucocorticoid metabolism and modulate signaling through corticosteroid receptors.
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Affiliation(s)
- Tijana Mitić
- Endocrinology, University/British Heart Foundation Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of Edinburgh, Edinburgh, EH16 4TJ, UK.
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18
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Mitić T, Andrew R, Walker BR, Hadoke PWF. 11β-Hydroxysteroid dehydrogenase type 1 contributes to the regulation of 7-oxysterol levels in the arterial wall through the inter-conversion of 7-ketocholesterol and 7β-hydroxycholesterol. Biochimie 2012; 95:548-55. [PMID: 22940536 PMCID: PMC3585959 DOI: 10.1016/j.biochi.2012.08.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 08/13/2012] [Indexed: 11/29/2022]
Abstract
The atherogenic 7-oxysterols, 7-ketocholesterol (7-KC) and 7β-hydroxycholesterol (7βOHC), can directly impair arterial function. Inter-conversion of 7-KC and 7βOHC has recently been shown as a novel role for the glucocorticoid-metabolizing enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). Since this enzyme is expressed in vascular smooth muscle cells, we addressed the hypothesis that inter-conversion of 7-KC and 7βOHC by 11β-HSD1 may contribute to regulation of arterial function. Incubation (4–24 h) of aortic rings with either 7-KC (25 μM) or 7βOHC (20 μM) had no effect on endothelium-dependent (acetylcholine) or -independent (sodium nitroprusside) relaxation. In contrast, exposure to 7-KC (but not to 7βOHC) attenuated noradrenaline-induced contraction (Emax) after 4 h (0.78 ± 0.28 vs 0.40 ± 0.08 mN/mm; p < 0.05) and 24 h (2.28 ± 0.34 vs 1.56 ± 0.48 mN/mm; p < 0.05). Both 7-oxysterols were detected by GCMS in the aortic wall of chow-fed C57Bl6/J mice, with concentrations of 7-KC (1.41 ± 0.81 ng/mg) higher (p = 0.05) than 7βOHC (0.16 ± 0.06 ng/mg). In isolated mouse aortic rings 11β-HSD1 was shown to act as an oxo-reductase, inter-converting 7-KC and 7βOHC. This activity was lost in aorta from 11β-HSD1−/− mice, which had low oxysterol levels. Renal homogenates from 11β-HSD1−/− mice were used to confirm that the type 2 isozyme of 11β-HSD does not inter-convert 7-KC and 7βOHC. These results demonstrate that 7-KC has greater effects than 7βOHC on vascular function, and that 11β-HSD1 can inter-convert 7-KC and 7βOHC in the arterial wall, contributing to the regulation of 7-oxysterol levels and potentially influencing vascular function. This mechanism may be important in the cardioprotective effects of 11β-HSD1 inhibitors.
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Affiliation(s)
- Tijana Mitić
- Endocrinology Unit, University/BHF Centre for Cardiovascular Science, College of Medicine and Veterinary Medicine, University of Edinburgh, The Queen's Medical Research Institute, Edinburgh, Scotland, UK
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19
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PARK SINHYE, KIM JUNGLYE, KANG MINKYUNG, GONG JUHYUN, HAN SEONYOUNG, SHIM JAEHOON, LIM SOONSUNG, KANG YOUNGHEE. Sage weed (Salvia plebeia) extract antagonizes foam cell formation and promotes cholesterol efflux in murine macrophages. Int J Mol Med 2012; 30:1105-12. [DOI: 10.3892/ijmm.2012.1103] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 07/27/2012] [Indexed: 11/05/2022] Open
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20
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Ohta M, Kawano H, Notsu T, Naba H, Imada K. Eicosapentaenoic acid attenuates statin-induced ER stress and toxicity in myoblast. Biochem Biophys Res Commun 2012; 424:301-7. [DOI: 10.1016/j.bbrc.2012.06.111] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 06/21/2012] [Indexed: 11/29/2022]
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21
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Leonarduzzi G, Gamba P, Gargiulo S, Biasi F, Poli G. Inflammation-related gene expression by lipid oxidation-derived products in the progression of atherosclerosis. Free Radic Biol Med 2012; 52:19-34. [PMID: 22037514 DOI: 10.1016/j.freeradbiomed.2011.09.031] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 09/16/2011] [Accepted: 09/24/2011] [Indexed: 12/31/2022]
Abstract
Vascular areas of atherosclerotic development persist in a state of inflammation, and any further inflammatory stimulus in the subintimal area elicits a proatherogenic response; this alters the behavior of the artery wall cells and recruits further inflammatory cells. In association with the inflammatory response, oxidative events are also involved in the development of atherosclerotic plaques. It is now unanimously recognized that lipid oxidation-derived products are key players in the initiation and progression of atherosclerotic lesions. Oxidized lipids, derived from oxidatively modified low-density lipoproteins (LDLs), which accumulate in the intima, strongly modulate inflammation-related gene expression, through involvement of various signaling pathways. In addition, considerable evidence supports a proatherogenic role of a large group of potent bioactive lipids called eicosanoids, which derive from oxidation of arachidonic acid, a component of membrane phospholipids. Of note, LDL lipid oxidation products might regulate eicosanoid production, modulating the enzymatic degradation of arachidonic acid by cyclooxygenases and lipoxygenases; these enzymes might also directly contribute to LDL oxidation. This review provides a comprehensive overview of current knowledge on signal transduction pathways and inflammatory gene expression, modulated by lipid oxidation-derived products, in the progression of atherosclerosis.
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22
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Lemaire-Ewing S, Lagrost L, Néel D. Lipid rafts: a signalling platform linking lipoprotein metabolism to atherogenesis. Atherosclerosis 2011; 221:303-10. [PMID: 22071358 DOI: 10.1016/j.atherosclerosis.2011.10.016] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 09/22/2011] [Accepted: 10/12/2011] [Indexed: 01/16/2023]
Abstract
Lipid rafts are microdomains of the plasma membrane which are enriched in cholesterol and sphingolipids. They serve as a platform for signal transduction, in particular during immune and inflammatory responses. As hypercholesterolemia and inflammation are two key elements of atherogenesis, it is conceivable that the cholesterol and cholesterol oxide content of lipid rafts might influence the inflammatory signalling pathways, thus modulating the development of atherosclerosis. In support of this emerging view, lipid rafts have been shown to be involved in several key steps of atherogenesis, such as the oxysterol-mediated apoptosis of vascular cells, the blunted ability of high density lipoproteins (HDL) to exert anti-inflammatory effects, and the exacerbated secretion of pro-inflammatory cytokines by immune cells. Additional studies are now required to address the relative contribution of lipid raft abnormalities to the pathophysiology of atherosclerosis and cardiovascular disease.
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23
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Mast cell death induced by 24(S),25-epoxycholesterol. Exp Cell Res 2010; 316:3272-81. [DOI: 10.1016/j.yexcr.2010.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Revised: 08/11/2010] [Accepted: 09/06/2010] [Indexed: 11/23/2022]
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24
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Netherland CD, Pickle TG, Bales A, Thewke DP. Cannabinoid receptor type 2 (CB2) deficiency alters atherosclerotic lesion formation in hyperlipidemic Ldlr-null mice. Atherosclerosis 2010; 213:102-8. [PMID: 20846652 DOI: 10.1016/j.atherosclerosis.2010.07.060] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 06/27/2010] [Accepted: 07/30/2010] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To determine if cannabinoid receptor 2 (CB2) plays a role in atherosclerosis, we investigated the effects of systemic CB2 gene deletion on hyperlipidemia-induced atherogenesis in low density lipoprotein receptor-deficient (Ldlr(-/-)) mice. METHODS AND RESULTS Ldlr(-/-) and CB2/Ldlr double knockout (CB2(-/-)Ldlr(-/-)) mice were fed an atherogenic diet for 8 and 12 weeks. Morphometric analysis revealed no significant difference between the atherosclerotic lesion area in the proximal aortas of Ldlr(-/-) and CB2(-/-)Ldlr(-/-) mice after 8 or 12 weeks on the atherogenic diet. The macrophage and smooth muscle cell (SMC) content, as revealed by immunohistochemical staining, did not differ significantly between Ldlr(-/-) and CB2(-/-)Ldlr(-/-) lesions after 8 weeks. However, after 12 weeks, CB2(-/-)Ldlr(-/-) lesions displayed greater macrophage content (86.6 ± 4.1 versus 75.2 ± 7.5%, P<0.05) and SMC content (11.1 ± 5.1 versus 4.2 ± 2.4%, P<0.05) compared to controls. Lesional apoptosis, as determined by in situ TUNEL analysis, was reduced ~50% in CB2(-/-)Ldlr(-/-) lesions after 12 weeks. CB2(-/-)Ldlr(-/-) lesions displayed significantly reduced collagen content and increased elastin fiber fragmentation after 12 weeks, which was associated with an ~57% increase in matrix metalloproteinase 9 (MMP) levels. In vitro, CB2(-/-) macrophages secreted ~1.8-fold more MMP9 activity than CB2(+/+) macrophages. CONCLUSIONS CB2 receptor deficiency affects atherogenesis in Ldlr-null mice by increasing lesional macrophage and SMC content, reducing lesional apoptosis and altering extracellular matrix components, in part, by upregulating MMP9. These results suggest that pharmacological manipulation of CB2 receptors might exert multiple and complex effects on atherogenesis and plaque stability.
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Affiliation(s)
- Courtney D Netherland
- Department of Biochemistry and Molecular Biology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614-0581, USA
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25
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Netherland C, Thewke DP. Rimonabant is a dual inhibitor of acyl CoA:cholesterol acyltransferases 1 and 2. Biochem Biophys Res Commun 2010; 398:671-6. [PMID: 20609360 PMCID: PMC2918681 DOI: 10.1016/j.bbrc.2010.06.134] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Accepted: 06/30/2010] [Indexed: 11/27/2022]
Abstract
Acyl coenzyme A:cholesterol acyltransferase (ACAT) catalyzes the intracellular synthesis of cholesteryl esters (CE). Both ACAT isoforms, ACAT1 and ACAT2, play key roles in the pathophysiology of atherosclerosis and ACAT inhibition retards atherosclerosis in animal models. Rimonabant, a type 1 cannabinoid receptor (CB1) antagonist, produces anti-atherosclerotic effects in humans and animals by mechanisms which are not completely understood. Rimonabant is structurally similar to two other cannabinoid receptor antagonists, AM251 and SR144528, recently identified as potent inhibitors of ACAT. Therefore, we examined the effects of Rimonabant on ACAT using both in vivo cell-based assays and in vitro cell-free assays. Rimonabant dose-dependently reduced ACAT activity in Raw 264.7 macrophages (IC(50)=2.9+/-0.38 microM) and isolated peritoneal macrophages. Rimonabant inhibited ACAT activity in intact CHO-ACAT1 and CHO-ACAT2 cells and in cell-free assays with approximately equal efficiency (IC(50)=1.5+/-1.2 microM and 2.2+/-1.1 microM for CHO-ACAT1 and CHO-ACAT2, respectively). Consistent with ACAT inhibition, Rimonabant treatment blocked ACAT-dependent processes in macrophages, oxysterol-induced apoptosis and acetylated-LDL induced foam cell formation. From these results we conclude that Rimonabant is an ACAT1/2 dual inhibitor and suggest that some of the atherosclerotic beneficial effects of Rimonabant are, at least partly, due to inhibition of ACAT.
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Affiliation(s)
- Courtney Netherland
- Department of Biochemistry and Molecular Biology, Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614
| | - Douglas P. Thewke
- Department of Biochemistry and Molecular Biology, Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614
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26
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Rodríguez IR, Larrayoz IM. Cholesterol oxidation in the retina: implications of 7KCh formation in chronic inflammation and age-related macular degeneration. J Lipid Res 2010; 51:2847-62. [PMID: 20567027 DOI: 10.1194/jlr.r004820] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
This review will discuss the formation and potential implications of 7-ketocholesterol (7KCh) in the retina. 7KCh is a proinflammatory oxysterol known to be present in high amounts in oxidized LDL deposits associated with atheromatous plaques. 7KCh is generated in situ in these lipoprotein deposits where it can accumulate and reach very high concentrations. In normal primate retina, 7KCh has been found associated with lipoprotein deposits in the choriocapillaris, Bruch's membrane, and the retinal pigment epithelium (RPE). In photodamaged rats, 7KCh has been found in the neural retina in areas of high mitochondrial content, ganglion cells, photoreceptor inner segments and synapses, and the RPE. Intermediates found by LCMS indicate 7KCh is formed via a free radical-mediated mechanism catalyzed by iron. 7KCh seems to activate several kinase signaling pathways that work via nuclear factor κB and cause the induction of vascular endothelial growth factor, interleukin (IL)-6, and IL-8. There seems to be little evidence of 7KCh metabolism in the retina, although some form of efflux mechanism may be active. The chronic mode of formation and the potent inflammatory properties of 7KCh indicate it may be an "age-related" risk factor in aging diseases such as atherosclerosis, Alzheimer's, and age-related macular degeneration.
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Affiliation(s)
- Ignacio R Rodríguez
- Mechanisms of Retinal Diseases Section, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, Bethesda, MD 20892, USA.
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27
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Schloendorn J, Webb T, Kemmish K, Hamalainen M, Jackemeyer D, Jiang L, Mathieu J, Rebo J, Sankman J, Sherman L, Tontson L, Qureshi A, Alvarez P, Rittmann B. Medical Bioremediation: A Concept Moving Toward Reality. Rejuvenation Res 2009; 12:411-9. [DOI: 10.1089/rej.2009.0917] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- John Schloendorn
- Biodesign Institute at Arizona State University, Tempe, Arizona
- SENS Foundation Research Center, Sunnyvale, California
| | - Tim Webb
- SENS Foundation Research Center, Sunnyvale, California
| | | | | | | | - Lijing Jiang
- Biodesign Institute at Arizona State University, Tempe, Arizona
| | - Jacques Mathieu
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas
| | - Justin Rebo
- SENS Foundation Research Center, Sunnyvale, California
- Department of Microbiology, St. George's University School of Medicine, Grenada, Wisconsin
| | | | - Lindsey Sherman
- Biodesign Institute at Arizona State University, Tempe, Arizona
| | - Lauri Tontson
- Biodesign Institute at Arizona State University, Tempe, Arizona
| | - Ateef Qureshi
- Department of Microbiology, St. George's University School of Medicine, Grenada, Wisconsin
| | - Pedro Alvarez
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas
| | - Bruce Rittmann
- Biodesign Institute at Arizona State University, Tempe, Arizona
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Liu J, Netherland C, Pickle T, Sinensky MS, Thewke DP. Stimulation of Akt poly-ubiquitination and proteasomal degradation in P388D1 cells by 7-ketocholesterol and 25-hydroxycholesterol. Arch Biochem Biophys 2009; 487:54-8. [PMID: 19464253 DOI: 10.1016/j.abb.2009.05.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 04/30/2009] [Accepted: 05/14/2009] [Indexed: 01/29/2023]
Abstract
Akt plays a role in protecting macrophages from apoptosis induced by some oxysterols. Previously we observed enhanced degradation of Akt in P388D1 moncocyte/macrophages following treatment with 25-hydroxycholesterol (25-OH) or 7-ketocholesterol (7-KC). In the present report we examine the role of the ubiquitin proteasomal pathway in this process. We show that treatment with 25-OH or 7-KC results in the accumulation of poly-ubiquitinated Akt, an effect that is enhanced by co-treatment with the proteasome inhibitor MG-132. Modification of Akt by the addition of a Gly-Ala repeat (GAr), a domain known to block ubiquitin-dependent targeting of proteins to the proteasome, resulted in a chimeric protein that is resistant to turn-over induced by 25-OH or 7-KC and provides protection from apoptosis induced by these oxysterols. These results uncover a new aspect of oxysterol regulation of Akt in macrophages; oxysterol-stimulated poly-ubiquitination of Akt and degradation by the proteasomal pathway.
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Affiliation(s)
- June Liu
- Department of Urology, University of Pittsburg School of Medicine, Pittsburg, PA 15232, USA
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29
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AM-251 and SR144528 are acyl CoA:cholesterol acyltransferase inhibitors. Biochem Biophys Res Commun 2009; 381:181-6. [PMID: 19338772 DOI: 10.1016/j.bbrc.2009.02.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2009] [Accepted: 02/03/2009] [Indexed: 11/21/2022]
Abstract
Oxysterol-induced macrophage apoptosis may have a role in atherosclerosis. Macrophages lacking the type 2 cannabinoid receptor (CB2) are partially resistant to apoptosis induced by 7-ketocholesterol (7KC). AM-251 and SR144528 are selective antagonists of CB1 and CB2 receptors, respectively. We observed that both compounds reduce 7KC-induced apoptosis in Raw 264.7 macrophages. As oxysterol-induced macrophage apoptosis requires acyl-coenzymeA:cholesterol acyltransferase (ACAT) activity, we tested their affects on ACAT activity. AM-251 and SR144528 both reduced cholesteryl ester synthesis in unstimulated and acetylated LDL-stimulated Raw 264.7 macrophages, CB2(+/+) and CB2(-/-) peritoneal macrophages, as well as in vitro, in mouse liver microsomes. Consistent with inhibition of ACAT, the development of foam cell characteristics in macrophages by treatment with acetylated LDL was reduced by both compounds. This work is the first evidence that AM-251 and SR144528 are inhibitors of ACAT and as a result, might have anti-atherosclerotic activities independent of their affect on cannabinoid signaling.
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Freeman-Anderson NE, Pickle TG, Netherland CD, Bales A, Buckley NE, Thewke DP. Cannabinoid (CB2) receptor deficiency reduces the susceptibility of macrophages to oxidized LDL/oxysterol-induced apoptosis. J Lipid Res 2008; 49:2338-46. [PMID: 18614816 DOI: 10.1194/jlr.m800105-jlr200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Macrophage apoptosis is an important process in the pathophysiology of atherosclerosis. Oxidized low-density lipoproteins (OxLDL) are a major component of lesions and potently induce macrophage apoptosis. Cannabinoid receptor 2 (CB2), the predominant macrophage cannabinoid receptor, modulates several macrophage processes associated with ongoing atherosclerosis; however, the role of CB2 in macrophage apoptosis is unknown. To determine if CB2 influences a macrophage apoptotic pathway relevant to atherosclerosis, we examined the effect of CB2 deficiency on OxLDL-induced macrophage apoptosis. In situ terminal transferase-mediated dUTP nick end labeling (TUNEL) analysis of resident peritoneal macrophages detected significantly fewer apoptotic CB2(-/-) macrophages than CB2(+/+) macrophages after incubation with OxLDL (27.9 +/- 4.7% vs. 61.9 +/- 8.5%, P < 0.001) or 7-ketocholesterol (7KC) (18.9 +/- 10.5% vs. 54.1 +/- 6.9%, P < 0.001), an oxysterol component of OxLDL. Caspase-3 activity; proteolytic conversion of procaspase-3; and cleavage of a caspase-3 substrate, PARP, were also diminished in 7KC-treated CB2(-/-) macrophages. Furthermore, the deactivation of the prosurvival kinase, Akt, in response to 7KC was impaired in CB2(-/-) macrophages. These results suggest that CB2 expression increases the susceptibility of macrophages to OxLDL-induced apoptosis, in part, by modulating the effect of oxysterols on the Akt survival pathway and that CB2 may influence atherosclerosis by modulating lesional macrophage apoptosis.
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Affiliation(s)
- Natalie E Freeman-Anderson
- Department of Biochemistry and Molecular Biology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
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Massey JB, Pownall HJ. Structures of biologically active oxysterols determine their differential effects on phospholipid membranes. Biochemistry 2006; 45:10747-58. [PMID: 16939227 DOI: 10.1021/bi060540u] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Oxysterols, derivatives of cholesterol that contain a second oxygen moiety, are intermediates in cholesterol catabolism, regulators of lipid metabolism, and toxic sterols with proatherogenic effects. In model membranes, cholesterol and eight selected oxysterols were compared by fluorescence probe techniques that measure changes in bilayer order and phase behavior and by the formation of detergent-resistant membranes (DRM). The oxysterols were modified on the sterol nucleus or on the isooctyl side chain. The model membranes consisted of dipalmitoyl phosphatidylcholine (DPPC) and mixtures of dioleoyl phosphatidylcholine with DPPC and with sphingomyelin. The different oxysterols induced changes in membrane properties according to the differences in their structures. Whereas the effects of some oxysterols on membrane order, fluorescence probe microenvironment, and DRM formation were similar to those of cholesterol, others had little or no effect. An empirical correlation ranking the oxysterols by their ability to modify membrane biophysical properties when compared to cholesterol led to a significant structure/function relationship between the biophysical measurements and an important cellular phenomenon, apoptosis. 7beta-Hydroxycholesterol, which is the most cytotoxic of the eight selected oxysterols, was one of the least cholesterol-like with respect to modification of membrane properties. The results suggest that an underlying mechanism for oxysterol-induced apoptosis in cells, e.g., monocyte/macrophages, should include their biophysical effects on membranes, such as the regulation of the formation and composition of sterol-rich membrane domains.
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Affiliation(s)
- John B Massey
- Section of Atherosclerosis and Lipoprotein Research, Department of Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.
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Abstract
PURPOSE OF REVIEW Oxysterols, oxidation products of cholesterol, mediate numerous and diverse biological processes. The objective of this review is to explain some of the biochemical and cell biological properties of oxysterols based on their membrane biophysical properties and their interaction with integral and peripheral membrane proteins. RECENT FINDINGS According to their biophysical properties, which can be distinct from those of cholesterol, oxysterols can promote or inhibit the formation of membrane microdomains or lipid rafts. Oxysterols that inhibit raft formation are cytotoxic. The stereo-specific binding of cholesterol to sterol-sensing domains in cholesterol homeostatic pathways is not duplicated by oxysterols, and some oxysterols are poor substrates for the pathways that detoxify cells of excess cholesterol. The cytotoxic roles of oxysterols are, at least partly, due to a direct physical effect on membranes involved in cholesterol-induced cell apoptosis and raft mediated cell signaling. Oxysterols regulate cellular functions by binding to oxysterol binding protein and oxysterol binding protein-related proteins. Oxysterol binding protein is a sterol-dependent scaffolding protein that regulates the extracellular signal-regulated kinase signaling pathway. According to a recently solved structure for a yeast oxysterol binding protein-related protein, Osh4, some members of this large family of proteins are likely sterol transporters. SUMMARY Given the association of some oxysterols with atherosclerosis, it is important to identify the mechanisms by which their association with cell membranes and intracellular proteins controls membrane structure and properties and intracellular signaling and metabolism. Studies on oxysterol binding protein and oxysterol binding protein-related proteins should lead to new understandings about sterol-regulated signal transduction and membrane trafficking pathways in cells.
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Affiliation(s)
- John B Massey
- Section of Atherosclerosis and Lipoprotein Research, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA.
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