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Tang Y, Fan Y, Wang Y, Wang D, Huang Q, Chen T, Cao X, Wen C, Shen X, Li J, You Y. A Current Understanding of FXR in NAFLD: The multifaceted regulatory role of FXR and novel lead discovery for drug development. Biomed Pharmacother 2024; 175:116658. [PMID: 38701562 DOI: 10.1016/j.biopha.2024.116658] [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: 02/13/2024] [Revised: 04/16/2024] [Accepted: 04/24/2024] [Indexed: 05/05/2024] Open
Abstract
The global prevalence of nonalcoholic fatty liver disease (NAFLD) has reached 30 %, with an annual increase. The incidence of NAFLD-induced cirrhosis is rapidly rising and has become the leading indicator for liver transplantation in the US. However, there are currently no US Food and Drug Administration-approved drugs for NAFLD. Increasing evidence underscores the close association between NAFLD and bile acid metabolism disorder, highlighting the feasibility of targeting the bile acid signaling pathway for NAFLD treatment. The farnesoid X receptor (FXR) is an endogenous receptor for bile acids that exhibits favorable effects in ameliorating the metabolic imbalance of bile acids, lipid disorders, and disruption of intestinal homeostasis, all of which are key characteristics of NAFLD, making FXR a promising therapeutic target for NAFLD. The present review provides a comprehensive overview of the diverse mechanisms through which FXR improves NAFLD, with particular emphasis on its involvement in regulating bile acid homeostasis and the recent advancements in drug development targeting FXR for NAFLD treatment.
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Affiliation(s)
- Yuhong Tang
- School of Pharmacy & Minhang Hospital, Fudan University, Shanghai, China
| | - Yujuan Fan
- School of Pharmacy & Minhang Hospital, Fudan University, Shanghai, China
| | - Yiming Wang
- Department of Cardiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Dong Wang
- School of Pharmacy & Minhang Hospital, Fudan University, Shanghai, China
| | - Qingyu Huang
- Department of Cardiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Tongqing Chen
- School of Pharmacy & Minhang Hospital, Fudan University, Shanghai, China
| | - Xinyue Cao
- School of Pharmacy & Minhang Hospital, Fudan University, Shanghai, China
| | - Cailing Wen
- School of Pharmacy & Minhang Hospital, Fudan University, Shanghai, China
| | - Xiaoyan Shen
- School of Pharmacy & Minhang Hospital, Fudan University, Shanghai, China.
| | - Jian Li
- Department of Cardiology, Huashan Hospital, Fudan University, Shanghai, China.
| | - Yan You
- School of Pharmacy & Minhang Hospital, Fudan University, Shanghai, China.
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2
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Roumain M, Guillemot-Legris O, Ameraoui H, Alhouayek M, Muccioli GG. Identification and in vivo detection of side-chain hydroxylated metabolites of 4β-hydroxycholesterol. J Steroid Biochem Mol Biol 2023; 234:106376. [PMID: 37604319 DOI: 10.1016/j.jsbmb.2023.106376] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 08/13/2023] [Accepted: 08/18/2023] [Indexed: 08/23/2023]
Abstract
Oxysterols are oxidized derivatives of cholesterol that are formed by enzymatic processes or through the action of reactive oxygen species. Several of these bioactive lipids have been shown to be affected and/or play a role in inflammatory processes. 4β-hydroxycholesterol is one of the major oxysterols in mice and humans and its levels are affected by inflammatory diseases. However, apart from its long half-life, little is known about its catabolism. By incubating 4β-hydroxycholesterol with mouse mitochondria-enriched liver fractions, as well as 25-hydroxycholesterol and 27-hydroxycholesterol with recombinant CYP3A4, we identified 4β,25-dihydroxycholesterol and 4β,27-dihydroxycholesterol as 4β-hydroxycholesterol metabolites. Supporting the biological relevance of this metabolism, we detected both metabolites after incubation of J774, primary mouse peritoneal macrophages and PMA-differentiated THP-1 cells with 4β-hydroxycholesterol. Across our experiments, the incubation of cells with lipopolysaccharides differentially affected the levels of the 25- and 27-hydroxylated metabolites of 4β-hydroxycholesterol. Finally, 4β,27-dihydroxycholesterol was also detected in mice liver and plasma after intraperitoneal administration of 4β-hydroxycholesterol. To our knowledge, this is the first report of the in vitro and in vivo detection and quantification of 4β-hydroxycholesterol metabolites.
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Affiliation(s)
- Martin Roumain
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Belgium
| | - Owein Guillemot-Legris
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Belgium
| | - Hafsa Ameraoui
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Belgium
| | - Mireille Alhouayek
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Belgium
| | - Giulio G Muccioli
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Belgium.
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3
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Zhang J, Zhu Y, Wang X, Wang J. 25-hydroxycholesterol: an integrator of antiviral ability and signaling. Front Immunol 2023; 14:1268104. [PMID: 37781400 PMCID: PMC10533924 DOI: 10.3389/fimmu.2023.1268104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 08/29/2023] [Indexed: 10/03/2023] Open
Abstract
Cholesterol, as an important component in mammalian cells, is efficient for viral entry, replication, and assembly. Oxysterols especially hydroxylated cholesterols are recognized as novel regulators of the innate immune response. The antiviral ability of 25HC (25-Hydroxycholesterol) is uncovered due to its role as a metabolic product of the interferon-stimulated gene CH25H (cholesterol-25-hydroxylase). With the advancement of research, the biological functions of 25HC and its structural functions have been interpreted gradually. Furthermore, the underlying mechanisms of antiviral effect of 25HC are not only limited to interferon regulation. Taken up by the special biosynthetic ways and structure, 25HC contributes to modulate not only the cholesterol metabolism but also autophagy and inflammation by regulating signaling pathways. The outcome of modulation by 25HC seems to be largely dependent on the cell types, viruses and context of cell microenvironments. In this paper, we review the recent proceedings on the regulatory effect of 25HC on interferon-independent signaling pathways related to its antiviral capacity and its putative underlying mechanisms.
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Affiliation(s)
- Jialu Zhang
- College of Veterinary Medicine, China Agricultural University, Beijing, China
- College of Veterinary Medicine, Sanya Institute of China Agricultural University, Sanya, China
| | - Yaohong Zhu
- College of Veterinary Medicine, China Agricultural University, Beijing, China
- College of Veterinary Medicine, Sanya Institute of China Agricultural University, Sanya, China
| | - Xiaojia Wang
- College of Veterinary Medicine, China Agricultural University, Beijing, China
- College of Veterinary Medicine, Sanya Institute of China Agricultural University, Sanya, China
| | - Jiufeng Wang
- College of Veterinary Medicine, China Agricultural University, Beijing, China
- College of Veterinary Medicine, Sanya Institute of China Agricultural University, Sanya, China
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Kømurcu KS, Wilhelmsen I, Thorne JL, Krauss S, Wilson SR, Aizenshtadt A, Røberg-Larsen H. Mass spectrometry reveals that oxysterols are secreted from non-alcoholic fatty liver disease induced organoids. J Steroid Biochem Mol Biol 2023; 232:106355. [PMID: 37380087 DOI: 10.1016/j.jsbmb.2023.106355] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 06/12/2023] [Accepted: 06/20/2023] [Indexed: 06/30/2023]
Abstract
Oxysterols are potential biomarkers for liver metabolism that are altered under disease conditions such as non-alcoholic fatty liver disease (NAFLD). We here apply sterolomics to organoids used for disease modeling of NAFLD. Using liquid chromatography-mass spectrometry with on-line sample clean-up and enrichment, we establish that liver organoids produce and secrete oxysterols. We find elevated levels of 26-hydroxycholesterol, an LXR agonist and the first oxysterol in the acidic bile acid synthesis, in medium from steatotic liver organoids compared to untreated organoids. Other upregulated sterols in medium from steatotic liver organoids are dihydroxycholesterols, such as 7α,26-dihydroxycholesterol, and 7α,25-dihydroxycholesterol. Through 26-hydroxycholesterol exposure to human stem cell-derived hepatic stellate cells, we observe a trend of expressional downregulation of the pro-inflammatory cytokine CCL2, suggesting a protective role of 26-hydroxycholesterol during early-phased NAFLD disease development. Our findings support the possibility of oxysterols serving as NAFLD indicators, demonstrating the usefulness of combining organoids and mass spectrometry for disease modeling and biomarker studies.
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Affiliation(s)
- Kristina Sæterdal Kømurcu
- Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, 0315 Oslo, Norway; Hybrid Technology Hub - Centre of Excellence, Institute of Basic Medical Sciences, University of Oslo, P.O. Box 1110 Blindern, 0317 Oslo, Norway
| | - Ingrid Wilhelmsen
- Hybrid Technology Hub - Centre of Excellence, Institute of Basic Medical Sciences, University of Oslo, P.O. Box 1110 Blindern, 0317 Oslo, Norway; Department of Immunology and Transfusion Medicine, Oslo University Hospital, Rikshospitalet, P.O. box 4950 Nydalen, Oslo, Norway
| | - James L Thorne
- School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Stefan Krauss
- Hybrid Technology Hub - Centre of Excellence, Institute of Basic Medical Sciences, University of Oslo, P.O. Box 1110 Blindern, 0317 Oslo, Norway; Department of Immunology and Transfusion Medicine, Oslo University Hospital, Rikshospitalet, P.O. box 4950 Nydalen, Oslo, Norway
| | - Steven Ray Wilson
- Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, 0315 Oslo, Norway; Hybrid Technology Hub - Centre of Excellence, Institute of Basic Medical Sciences, University of Oslo, P.O. Box 1110 Blindern, 0317 Oslo, Norway
| | - Aleksandra Aizenshtadt
- Hybrid Technology Hub - Centre of Excellence, Institute of Basic Medical Sciences, University of Oslo, P.O. Box 1110 Blindern, 0317 Oslo, Norway
| | - Hanne Røberg-Larsen
- Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, 0315 Oslo, Norway; Hybrid Technology Hub - Centre of Excellence, Institute of Basic Medical Sciences, University of Oslo, P.O. Box 1110 Blindern, 0317 Oslo, Norway.
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Asano T, Wakabayashi T, Kondo Y, Okada K, Yamamuro D, Koga Y, Oka K, Sakurai M, Sawayama N, Takahashi M, Okazaki H, Ebihara K, Minami K, Morisawa Y, Hatakeyama S, Matsumura M, Ishibashi S. Serum 25-hydroxycholesterol levels are increased in patients with coronavirus disease 2019. J Clin Lipidol 2023; 17:78-86. [PMID: 36522261 PMCID: PMC9637049 DOI: 10.1016/j.jacl.2022.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 10/28/2022] [Accepted: 10/31/2022] [Indexed: 11/09/2022]
Abstract
BACKGROUND 25-hydroxycholesterol (25HC), produced by cholesterol 25-hydroxylase (CH25H) in macrophages, has been reported to inhibit the replication of viral pathogens such as severe acute respiratory syndrome coronavirus-2. Also, CH25H expression in macrophages is robustly induced by interferons (IFNs). OBJECTIVE To better understand the serum level increase of 25HC in coronavirus disease 2019 (COVID-19) and how it relates to the clinical picture. METHODS We measured the serum levels of 25HC and five other oxysterols in 17 hospitalized COVID-19 patients. RESULTS On admission, 25HC and 27-hydroxycholesterol (27HC) serum levels were elevated; however, 7-ketocholesterol (7KC) levels were lower in patients with COVID-19 than in the healthy controls. There was no significant correlation between 25HC serum levels and disease severity markers, such as interferon-gamma (IFN-γ) and interleukin 6. Dexamethasone effectively suppressed cholesterol 25-hydroxylase (CH25H) mRNA expression in RAW 264.7 cells, a murine leukemia macrophage cell line, with or without lipopolysaccharide or IFNs; therefore, it might mitigate the increasing effects of COVID-19 on the serum levels of 25HC. CONCLUSIONS Our results highlighted that 25HC could be used as a unique biomarker in severe COVID-19 and a potential therapeutic candidate for detecting the severity of COVID-19 and other infectious diseases.
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Affiliation(s)
- Takumi Asano
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan (Drs Asano, Wakabayashi, Kondo, Okada, Yamamuro, Koga, Oka, Sakurai, Sawayama, Takahashi, Okazaki, Ebihara and Ishibashi)
| | - Tetsuji Wakabayashi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan (Drs Asano, Wakabayashi, Kondo, Okada, Yamamuro, Koga, Oka, Sakurai, Sawayama, Takahashi, Okazaki, Ebihara and Ishibashi)
| | - Yasuyuki Kondo
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan (Drs Asano, Wakabayashi, Kondo, Okada, Yamamuro, Koga, Oka, Sakurai, Sawayama, Takahashi, Okazaki, Ebihara and Ishibashi)
| | - Kenta Okada
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan (Drs Asano, Wakabayashi, Kondo, Okada, Yamamuro, Koga, Oka, Sakurai, Sawayama, Takahashi, Okazaki, Ebihara and Ishibashi)
| | - Daisuke Yamamuro
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan (Drs Asano, Wakabayashi, Kondo, Okada, Yamamuro, Koga, Oka, Sakurai, Sawayama, Takahashi, Okazaki, Ebihara and Ishibashi)
| | - Yukiko Koga
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan (Drs Asano, Wakabayashi, Kondo, Okada, Yamamuro, Koga, Oka, Sakurai, Sawayama, Takahashi, Okazaki, Ebihara and Ishibashi)
| | - Kiyonori Oka
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan (Drs Asano, Wakabayashi, Kondo, Okada, Yamamuro, Koga, Oka, Sakurai, Sawayama, Takahashi, Okazaki, Ebihara and Ishibashi)
| | - Momoe Sakurai
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan (Drs Asano, Wakabayashi, Kondo, Okada, Yamamuro, Koga, Oka, Sakurai, Sawayama, Takahashi, Okazaki, Ebihara and Ishibashi)
| | - Nagisa Sawayama
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan (Drs Asano, Wakabayashi, Kondo, Okada, Yamamuro, Koga, Oka, Sakurai, Sawayama, Takahashi, Okazaki, Ebihara and Ishibashi)
| | - Manabu Takahashi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan (Drs Asano, Wakabayashi, Kondo, Okada, Yamamuro, Koga, Oka, Sakurai, Sawayama, Takahashi, Okazaki, Ebihara and Ishibashi)
| | - Hiroaki Okazaki
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan (Drs Asano, Wakabayashi, Kondo, Okada, Yamamuro, Koga, Oka, Sakurai, Sawayama, Takahashi, Okazaki, Ebihara and Ishibashi)
| | - Ken Ebihara
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan (Drs Asano, Wakabayashi, Kondo, Okada, Yamamuro, Koga, Oka, Sakurai, Sawayama, Takahashi, Okazaki, Ebihara and Ishibashi)
| | - Kensuke Minami
- Division of Infectious Diseases, Jichi Medical University Hospital, Shimotsuke, Tochigi, Japan (Drs Minami and Morisawa)
| | - Yuji Morisawa
- Division of Infectious Diseases, Jichi Medical University Hospital, Shimotsuke, Tochigi, Japan (Drs Minami and Morisawa)
| | - Shuji Hatakeyama
- Division of General Medicine, Center for Community Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan (Drs Hatakeyama and Matsumura)
| | - Masami Matsumura
- Division of General Medicine, Center for Community Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan (Drs Hatakeyama and Matsumura)
| | - Shun Ishibashi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan (Drs Asano, Wakabayashi, Kondo, Okada, Yamamuro, Koga, Oka, Sakurai, Sawayama, Takahashi, Okazaki, Ebihara and Ishibashi).
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6
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Jiao TY, Ma YD, Guo XZ, Ye YF, Xie C. Bile acid and receptors: biology and drug discovery for nonalcoholic fatty liver disease. Acta Pharmacol Sin 2022; 43:1103-1119. [PMID: 35217817 PMCID: PMC9061718 DOI: 10.1038/s41401-022-00880-z] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 01/25/2022] [Indexed: 02/07/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD), a series of liver metabolic disorders manifested by lipid accumulation within hepatocytes, has become the primary cause of chronic liver diseases worldwide. About 20%-30% of NAFLD patients advance to nonalcoholic steatohepatitis (NASH), along with cell death, inflammation response and fibrogenesis. The pathogenesis of NASH is complex and its development is strongly related to multiple metabolic disorders (e.g. obesity, type 2 diabetes and cardiovascular diseases). The clinical outcomes include liver failure and hepatocellular cancer. There is no FDA-approved NASH drug so far, and thus effective therapeutics are urgently needed. Bile acids are synthesized in hepatocytes, transported into the intestine, metabolized by gut bacteria and recirculated back to the liver by the enterohepatic system. They exert pleiotropic roles in the absorption of fats and regulation of metabolism. Studies on the relevance of bile acid disturbance with NASH render it as an etiological factor in NASH pathogenesis. Recent findings on the functional identification of bile acid receptors have led to a further understanding of the pathophysiology of NASH such as metabolic dysregulation and inflammation, and bile acid receptors are recognized as attractive targets for NASH treatment. In this review, we summarize the current knowledge on the role of bile acids and the receptors in the development of NAFLD and NASH, especially the functions of farnesoid X receptor (FXR) in different tissues including liver and intestine. The progress in the development of bile acid and its receptors-based drugs for the treatment of NASH including bile acid analogs and non-bile acid modulators on bile acid metabolism is also discussed.
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Affiliation(s)
- Ting-Ying Jiao
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Yuan-di Ma
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiao-Zhen Guo
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Yun-Fei Ye
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Cen Xie
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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7
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Griffiths WJ, Wang Y. Cholesterol metabolism: from lipidomics to immunology. J Lipid Res 2022; 63:100165. [PMID: 34953867 PMCID: PMC8953665 DOI: 10.1016/j.jlr.2021.100165] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 12/10/2021] [Accepted: 12/13/2021] [Indexed: 12/15/2022] Open
Abstract
Oxysterols, the oxidized forms of cholesterol or of its precursors, are formed in the first steps of cholesterol metabolism. Oxysterols have interested chemists, biologists, and physicians for many decades, but their exact biological relevance in vivo, other than as intermediates in bile acid biosynthesis, has long been debated. However, in the first quarter of this century, a role for side-chain oxysterols and their C-7 oxidized metabolites has been convincingly established in the immune system. 25-Hydroxycholesterol has been shown to be synthesized by macrophages in response to the activation of Toll-like receptors and to offer protection against microbial pathogens, whereas 7α,25-dihydroxycholesterol has been shown to act as a chemoattractant to lymphocytes expressing the G protein-coupled receptor Epstein-Barr virus-induced gene 2 and to be important in coordinating the action of B cells, T cells, and dendritic cells in secondary lymphoid tissue. There is a growing body of evidence that not only these two oxysterols but also many of their isomers are of importance to the proper function of the immune system. Here, we review recent findings related to the roles of oxysterols in immunology.
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Affiliation(s)
| | - Yuqin Wang
- Swansea University Medical School, Swansea, Wales, United Kingdom.
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Kakiyama G, Marques D, Takei H, Nittono H, Erickson S, Fuchs M, Rodriguez-Agudo D, Gil G, Hylemon PB, Zhou H, Bajaj JS, Pandak WM. Mitochondrial oxysterol biosynthetic pathway gives evidence for CYP7B1 as controller of regulatory oxysterols. J Steroid Biochem Mol Biol 2019; 189:36-47. [PMID: 30710743 DOI: 10.1016/j.jsbmb.2019.01.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 01/17/2019] [Accepted: 01/22/2019] [Indexed: 12/13/2022]
Abstract
The aim of this paper was to more completely study the mitochondrial CYP27A1 initiated acidic pathway of cholesterol metabolism. The mitochondrial CYP27A1 initiated pathway of cholesterol metabolism (acidic pathway) is known to synthesize two well-described vital regulators of cholesterol/lipid homeostasis, (25R)-26-hydroxycholesterol (26HC) and 25-hydroxycholesterol (25HC). Both 26HC and 25HC have been shown to be subsequently 7α-hydroxylated by Cyp7b1; reducing their regulatory abilities and furthering their metabolism to chenodeoxycholic acid (CDCA). Cholesterol delivery into the inner mitochondria membrane, where CYP27A1 is located, is considered the pathway's only rate-limiting step. To further explore the pathway, we increased cholesterol transport into mitochondrial CYP27A1 by selectively increased expression of the gene encoding the steroidogenic acute transport protein (StarD1). StarD1 overexpression led to an unanticipated marked down-regulation of oxysterol 7α-hydroxylase (Cyp7b1), a marked increase in 26HC, and the formation of a third vital regulatory oxysterol, 24(S)-hydroxycholesterol (24HC), in B6/129 mice livers. To explore the further metabolism of 24HC, as well as, 25HC and 26HC, characterizations of oxysterols and bile acids using three murine models (StarD1 overexpression, Cyp7b1-/-, Cyp27a1-/-) and human Hep G2 cells were conducted. This report describes the discovery of a new mitochondrial-initiated pathway of oxysterol/bile acid biosynthesis. Just as importantly, it provides evidence for CYP7B1 as a key regulator of three vital intracellular regulatory oxysterol levels.
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Affiliation(s)
- Genta Kakiyama
- Department of Internal Medicine, Virginia Commonwealth University, United States; Department of Veterans Affairs, Richmond, VA, United States.
| | - Dalila Marques
- Department of Internal Medicine, Virginia Commonwealth University, United States; Department of Veterans Affairs, Richmond, VA, United States
| | - Hajime Takei
- Junshin Clinic Bile Acid Institute, Tokyo, Japan
| | | | - Sandra Erickson
- School of Medicine, University of California, San Francisco, United States
| | - Michael Fuchs
- Department of Internal Medicine, Virginia Commonwealth University, United States; Department of Veterans Affairs, Richmond, VA, United States
| | - Daniel Rodriguez-Agudo
- Department of Internal Medicine, Virginia Commonwealth University, United States; Department of Veterans Affairs, Richmond, VA, United States
| | - Gregorio Gil
- Department of Biochemistry & Molecular Biology, Virginia Commonwealth University, United States
| | - Phillip B Hylemon
- Department of Microbiology and Immunology, Virginia Commonwealth University, United States; Department of Veterans Affairs, Richmond, VA, United States
| | - Huiping Zhou
- Department of Microbiology and Immunology, Virginia Commonwealth University, United States; Department of Veterans Affairs, Richmond, VA, United States
| | - Jasmohan S Bajaj
- Department of Internal Medicine, Virginia Commonwealth University, United States; Department of Veterans Affairs, Richmond, VA, United States
| | - William M Pandak
- Department of Internal Medicine, Virginia Commonwealth University, United States; Department of Veterans Affairs, Richmond, VA, United States
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9
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Caridis AM, Lightbody RJ, Tarlton JMR, Dolan S, Graham A. Genetic obesity increases pancreatic expression of mitochondrial proteins which regulate cholesterol efflux in BRIN-BD11 insulinoma cells. Biosci Rep 2019; 39:BSR20181155. [PMID: 30819824 PMCID: PMC6430727 DOI: 10.1042/bsr20181155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 01/29/2019] [Accepted: 02/26/2019] [Indexed: 11/24/2022] Open
Abstract
Pancreatic β-cells are sensitive to fluctuations in cholesterol content, which can damage the insulin secretion pathway, contributing to the aetiology of type 2 diabetes mellitus. Cholesterol efflux to (apo)lipoproteins, via ATP-binding cassette (ABC) transporter A1 (ABCA1), can prevent intracellular cholesterol accumulation; in some peripheral cells, ABCA1-dependent efflux is enhanced by promotion of cholesterol trafficking to, and generation of Liver X receptor (LXR) ligands by, mitochondrial sterol 27-hydroxylase (Cyp27A1 (cytochrome P450 27 A1/sterol 27-hydroxylase)) and its redox partners, adrenodoxin (ADX) and ADX reductase (ADXR). Despite this, the roles of mitochondrial cholesterol trafficking (steroidogenic acute regulatory protein [StAR] and 18-kDa translocator protein [TSPO]) and metabolising proteins in insulin-secreting cells remain wholly uncharacterised. Here, we demonstrate an increase in pancreatic expression of Cyp27A1, ADXR, TSPO and LXRα, but not ADX or StAR, in obese (fa/fa) rodents compared with lean (Fa/?) controls. Overexpression of Cyp27A1 alone in BRIN-BD11 cells increased INS2 expression, without affecting lipid metabolism; however, after exposure to low-density lipoprotein (LDL), cholesterol efflux to (apo)lipoprotein acceptors was enhanced in Cyp27A1-overexpressing cells. Co-transfection of Cyp27A1, ADX and ADXR, at a ratio approximating that in pancreatic tissue, stimulated cholesterol efflux to apolipoprotein A-I (apoA-I) in both basal and cholesterol-loaded cells; insulin release was stimulated equally by all acceptors in cholesterol-loaded cells. Thus, genetic obesity increases pancreatic expression of Cyp27A1, ADXR, TSPO and LXRα, while modulation of Cyp27A1 and its redox partners promotes cholesterol efflux from insulin-secreting cells to acceptor (apo)lipoproteins; this response may help guard against loss of insulin secretion caused by accumulation of excess intracellular cholesterol.
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Affiliation(s)
- Anna-Maria Caridis
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom
| | - Richard J Lightbody
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom
| | - Jamie M R Tarlton
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom
| | - Sharron Dolan
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom
| | - Annette Graham
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom
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10
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Vigne S, Chalmin F, Duc D, Clottu AS, Apetoh L, Lobaccaro JMA, Christen I, Zhang J, Pot C. IL-27-Induced Type 1 Regulatory T-Cells Produce Oxysterols that Constrain IL-10 Production. Front Immunol 2017; 8:1184. [PMID: 28993775 PMCID: PMC5622150 DOI: 10.3389/fimmu.2017.01184] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 09/07/2017] [Indexed: 01/09/2023] Open
Abstract
The behaviors of lymphocytes, including CD4+ T helper cells, are controlled on many levels by internal metabolic properties. Lipid metabolites have recently been ascribed a novel function as immune response modulators and perturbation of steroids pathways modulates inflammation and potentially promotes a variety of diseases. However, the impact of lipid metabolism on autoimmune disease development and lymphocyte biology is still largely unraveled. In this line, oxysterols, oxidized forms of cholesterol, have pleiotropic roles on the immune response aside from their involvements in lipid metabolism. The oxysterols 25-hydroxycholesterol (25-OHC) and 7α,25-dihydroxycholesterol (7α,25-OHC) regulate antiviral immunity and immune cell chemotaxis. However, their physiological effects on adaptive immune response in particular on various subset CD4+ T lymphocytes are largely unknown. Here, we assessed oxysterol levels in subset of CD4+ T cells and demonstrated that 25-OHC and transcript levels of its synthesizing enzyme, cholesterol 25-hydroxylase, were specifically increased in IL-27-induced type 1 regulatory T (TR1) cells. We further showed that 25-OHC acts as a negative regulator of TR1 cells in particular of IL-10 secretion via liver X receptor signaling. Not only do these findings unravel molecular mechanisms accounting for IL-27 signaling but also they highlight oxysterols as pro-inflammatory mediators that dampens regulatory T cell responses and thus unleash a pro-inflammatory response.
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Affiliation(s)
- Solenne Vigne
- Laboratories of Neuroimmunology, Division of Neurology and Neuroscience Research Center, Department of Clinical Neurosciences, Lausanne University Hospital, Lausanne, Switzerland
| | - Fanny Chalmin
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Donovan Duc
- Laboratories of Neuroimmunology, Division of Neurology and Neuroscience Research Center, Department of Clinical Neurosciences, Lausanne University Hospital, Lausanne, Switzerland
| | - Aurélie S Clottu
- Laboratories of Neuroimmunology, Division of Neurology and Neuroscience Research Center, Department of Clinical Neurosciences, Lausanne University Hospital, Lausanne, Switzerland
| | - Lionel Apetoh
- Faculté de Médecine, University of Bourgogne, INSERM U866, Centre Georges François Leclerc, Dijon, France
| | - Jean-Marc A Lobaccaro
- GReD, Université Clermont Auvergne, CNRS, INSERM, CRNH Auvergne, Clermont-Ferrand, France
| | - Isabelle Christen
- Analytical Sciences and Imaging, Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Juan Zhang
- Analytical Sciences and Imaging, Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Caroline Pot
- Laboratories of Neuroimmunology, Division of Neurology and Neuroscience Research Center, Department of Clinical Neurosciences, Lausanne University Hospital, Lausanne, Switzerland.,Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
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11
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Mutemberezi V, Guillemot-Legris O, Muccioli GG. Oxysterols: From cholesterol metabolites to key mediators. Prog Lipid Res 2016; 64:152-169. [PMID: 27687912 DOI: 10.1016/j.plipres.2016.09.002] [Citation(s) in RCA: 235] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 09/13/2016] [Accepted: 09/23/2016] [Indexed: 12/13/2022]
Abstract
Oxysterols are cholesterol metabolites that can be produced through enzymatic or radical processes. They constitute a large family of lipids (i.e. the oxysterome) involved in a plethora of physiological processes. They can act through GPCR (e.g. EBI2, SMO, CXCR2), nuclear receptors (LXR, ROR, ERα) and through transporters or regulatory proteins. Their physiological effects encompass cholesterol, lipid and glucose homeostasis. Additionally, they were shown to be involved in other processes such as immune regulatory functions and brain homeostasis. First studied as precursors of bile acids, they quickly emerged as interesting lipid mediators. Their levels are greatly altered in several pathologies and some oxysterols (e.g. 4β-hydroxycholesterol or 7α-hydroxycholestenone) are used as biomarkers of specific pathologies. In this review, we discuss the complex metabolism and molecular targets (including binding properties) of these bioactive lipids in human and mice. We also discuss the genetic mouse models currently available to interrogate their effects in pathophysiological settings. We also summarize the levels of oxysterols reported in two key organs in oxysterol metabolism (liver and brain), plasma and cerebrospinal fluid. Finally, we consider future opportunities and directions in the oxysterol field in order to gain a better insight and understanding of the complex oxysterol system.
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Affiliation(s)
- Valentin Mutemberezi
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Université catholique de Louvain, Belgium
| | - Owein Guillemot-Legris
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Université catholique de Louvain, Belgium
| | - Giulio G Muccioli
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Université catholique de Louvain, Belgium.
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12
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Graham A. Mitochondrial regulation of macrophage cholesterol homeostasis. Free Radic Biol Med 2015; 89:982-92. [PMID: 26416507 DOI: 10.1016/j.freeradbiomed.2015.08.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 07/28/2015] [Accepted: 08/11/2015] [Indexed: 12/19/2022]
Abstract
This review explores the relationship between mitochondrial structure and function in the regulation of macrophage cholesterol metabolism and proposes that mitochondrial dysfunction contributes to loss of the elegant homeostatic mechanisms which normally maintain cellular sterol levels within defined limits. Mitochondrial sterol 27-hydroxylase (CYP27A1) can generate oxysterol activators of liver X receptors which heterodimerise with retinoid X receptors, enhancing the transcription of ATP binding cassette transporters (ABCA1, ABCG1, and ABCG4), that can remove excess cholesterol via efflux to apolipoproteins A-1, E, and high density lipoprotein, and inhibit inflammation. The activity of CYP27A1 is regulated by the rate of supply of cholesterol substrate to the inner mitochondrial membrane, mediated by a complex of proteins. The precise identity of this dynamic complex remains controversial, even in steroidogenic tissues, but may include steroidogenic acute regulatory protein and the 18 kDa translocator protein, together with voltage-dependent anion channels, ATPase AAA domain containing protein 3A, and optic atrophy type 1 proteins. Certainly, overexpression of StAR and TSPO proteins can enhance macrophage cholesterol efflux to apoA-I and/or HDL, while perturbations in mitochondrial function, or changes in the expression of mitochondrial fusion proteins, alter the efficiency of cholesterol efflux. Molecules which can sustain or improve mitochondrial function or increase the activity of the protein complex involved in cholesterol transfer may have utility in resolving the problem of dysregulated macrophage cholesterol homeostasis, a condition which may contribute to inflammation, atherosclerosis, nonalcoholic steatohepatitis, osteoblastic bone resorption, and some disorders of the central nervous system.
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Affiliation(s)
- Annette Graham
- Department of Life Sciences, School of Health and Life Sciences, and Institute for Applied Health Research, Glasgow Caledonian University, 70 Cowcaddens Road, Glasgow G4 0BA, United Kingdom.
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13
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John C, Werner P, Worthmann A, Wegner K, Tödter K, Scheja L, Rohn S, Heeren J, Fischer M. A liquid chromatography-tandem mass spectrometry-based method for the simultaneous determination of hydroxy sterols and bile acids. J Chromatogr A 2014; 1371:184-95. [DOI: 10.1016/j.chroma.2014.10.064] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 10/20/2014] [Accepted: 10/21/2014] [Indexed: 01/07/2023]
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14
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Lathe R, Sapronova A, Kotelevtsev Y. Atherosclerosis and Alzheimer--diseases with a common cause? Inflammation, oxysterols, vasculature. BMC Geriatr 2014; 14:36. [PMID: 24656052 PMCID: PMC3994432 DOI: 10.1186/1471-2318-14-36] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 02/26/2014] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Aging is accompanied by increasing vulnerability to pathologies such as atherosclerosis (ATH) and Alzheimer disease (AD). Are these different pathologies, or different presentations with a similar underlying pathoetiology? DISCUSSION Both ATH and AD involve inflammation, macrophage infiltration, and occlusion of the vasculature. Allelic variants in common genes including APOE predispose to both diseases. In both there is strong evidence of disease association with viral and bacterial pathogens including herpes simplex and Chlamydophila. Furthermore, ablation of components of the immune system (or of bone marrow-derived macrophages alone) in animal models restricts disease development in both cases, arguing that both are accentuated by inflammatory/immune pathways. We discuss that amyloid β, a distinguishing feature of AD, also plays a key role in ATH. Several drugs, at least in mouse models, are effective in preventing the development of both ATH and AD. Given similar age-dependence, genetic underpinnings, involvement of the vasculature, association with infection, Aβ involvement, the central role of macrophages, and drug overlap, we conclude that the two conditions reflect different manifestations of a common pathoetiology. MECHANISM Infection and inflammation selectively induce the expression of cholesterol 25-hydroxylase (CH25H). Acutely, the production of 'immunosterol' 25-hydroxycholesterol (25OHC) defends against enveloped viruses. We present evidence that chronic macrophage CH25H upregulation leads to catalyzed esterification of sterols via 25OHC-driven allosteric activation of ACAT (acyl-CoA cholesterol acyltransferase/SOAT), intracellular accumulation of cholesteryl esters and lipid droplets, vascular occlusion, and overt disease. SUMMARY We postulate that AD and ATH are both caused by chronic immunologic challenge that induces CH25H expression and protection against particular infectious agents, but at the expense of longer-term pathology.
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Affiliation(s)
- Richard Lathe
- State University of Pushchino, Prospekt Nauki, Pushchino 142290, Moscow Region, Russia
- Pushchino Branch of the Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino 142290 Moscow Region, Russia
- Pieta Research, PO Box 27069, Edinburgh EH10 5YW, UK
| | - Alexandra Sapronova
- State University of Pushchino, Prospekt Nauki, Pushchino 142290, Moscow Region, Russia
- Pushchino Branch of the Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino 142290 Moscow Region, Russia
- Optical Research Group, Laboratory of Evolutionary Biophysics of Development, Institute of Developmental Biology of the Russian Academy of Sciences, Moscow, Russia
| | - Yuri Kotelevtsev
- State University of Pushchino, Prospekt Nauki, Pushchino 142290, Moscow Region, Russia
- Pushchino Branch of the Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino 142290 Moscow Region, Russia
- Biomedical Centre for Research Education and Innovation (CREI), Skolkovo Institute of Science and Technology, Skolkovo 143025, Russia
- Centre for Cardiovascular Science, Queens Medical Research Institute, University of Edinburgh, Little France, Edinburgh EH16 4TJ, UK
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15
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Endo-Umeda K, Yasuda K, Sugita K, Honda A, Ohta M, Ishikawa M, Hashimoto Y, Sakaki T, Makishima M. 7-Dehydrocholesterol metabolites produced by sterol 27-hydroxylase (CYP27A1) modulate liver X receptor activity. J Steroid Biochem Mol Biol 2014; 140:7-16. [PMID: 24269243 DOI: 10.1016/j.jsbmb.2013.11.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 10/26/2013] [Accepted: 11/12/2013] [Indexed: 01/06/2023]
Abstract
7-Dehydrocholesterol (7-DHC) is a common precursor of vitamin D3 and cholesterol. Although various oxysterols, oxygenated cholesterol derivatives, have been implicated in cellular signaling pathways, 7-DHC metabolism and potential functions of its metabolites remain poorly understood. We examined 7-DHC metabolism by various P450 enzymes and detected three metabolites produced by sterol 27-hydroxylase (CYP27A1) using high-performance liquid chromatography. Two were further identified as 25-hydroxy-7-DHC and 26/27-hydroxy-7-DHC. These 7-DHC metabolites were detected in serum of a patient with Smith-Lemli-Opitz syndrome. Luciferase reporter assays showed that 25-hydroxy-7-DHC activates liver X receptor (LXR) α, LXRβ and vitamin D receptor and that 26/27-hydroxy-7-DHC induces activation of LXRα and LXRβ, although the activities of both compounds on LXRs were weak. In a mammalian two-hybrid assay, 25-hydroxy-7-DHC and 26/27-hydroxy-7-DHC induced interaction between LXRα and a coactivator fragment less efficiently than a natural LXR agonist, 22(R)-hydroxycholesterol. These 7-DHC metabolites did not oppose agonist-induced LXR activation and interacted directly to LXRα in a manner distinct from a potent agonist. These findings indicate that the 7-DHC metabolites are partial LXR activators. Interestingly, 25-hydroxy-7-DHC and 26/27-hydroxy-7-DHC suppressed mRNA expression of sterol regulatory element-binding protein 1c, an LXR target gene, in HepG2 cells and HaCaT cells, while they weakly increased mRNA levels of ATP-binding cassette transporter A1, another LXR target, in HaCaT cells. Thus, 7-DHC is catabolized by CYP27A1 to metabolites that act as selective LXR modulators.
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Affiliation(s)
- Kaori Endo-Umeda
- Division of Biochemistry, Department of Biomedical Sciences, Nihon University School of Medicine, Itabashi-ku, Tokyo 173-8610, Japan
| | - Kaori Yasuda
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Kazuyuki Sugita
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Akira Honda
- Joint Research Center, Tokyo Medical University Ibaraki Medical Center, Ami, Ibaraki 300-0395, Japan
| | - Miho Ohta
- Department of Nutrition and Health, Faculty of Human Development, Soai University, Suminoe-ku, Osaka 559-0033, Japan
| | - Minoru Ishikawa
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Yuichi Hashimoto
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Toshiyuki Sakaki
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Makoto Makishima
- Division of Biochemistry, Department of Biomedical Sciences, Nihon University School of Medicine, Itabashi-ku, Tokyo 173-8610, Japan.
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16
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Kannenberg F, Gorzelniak K, Jäger K, Fobker M, Rust S, Repa J, Roth M, Björkhem I, Walter M. Characterization of cholesterol homeostasis in telomerase-immortalized Tangier disease fibroblasts reveals marked phenotype variability. J Biol Chem 2013; 288:36936-47. [PMID: 24196952 DOI: 10.1074/jbc.m113.500256] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
We compared the consequences of an ABCA1 mutation that produced an apparent lack of atherosclerosis (Tangier family 1, N935S) with an ABCA1 mutation with functional ABCA1 knockout that was associated with severe atherosclerosis (Tangier family 2, Leu(548):Leu(575)-End), using primary and telomerase-immortalized fibroblasts. Telomerase-immortalized Tangier fibroblasts of family 1 (TT1) showed 30% residual cholesterol efflux capacity in response to apolipoprotein A-I, whereas telomerase-immortalized Tangier fibroblasts of family 2 (TT2) showed only 20%. However, there were a number of secondary differences that were often stronger and may help to explain the more rapid development of atherosclerosis in family 2. First, the total cellular cholesterol content increase was 2-3-fold and 3-5-fold in TT1 and TT2 cells, respectively. The corresponding increase in esterified cholesterol concentration was 10- and 40-fold, respectively. Second, 24-, 25-, and 27-hydroxycholesterol concentrations were moderately increased in TT1 cells, but were increased as much as 200-fold in TT2 cells. Third, cholesterol biosynthesis was moderately decreased in TT1 cells, but was markedly decreased in TT2 cells. Fourth, potentially atheroprotective LXR-dependent SREBP1c signaling was normal in TT1, but was rather suppressed in TT2 cells. Cultivated primary Tangier fibroblasts were characterized by premature aging in culture and were associated with less obvious biochemical differences. In summary, these results may help to understand the differential atherosclerotic susceptibility in Tangier disease and further demonstrate the usefulness of telomerase-immortalized cells in studying this cellular phenotype. The data support the contention that side chain-oxidized oxysterols are strong suppressors of cholesterol biosynthesis under specific pathological conditions in humans.
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Affiliation(s)
- Frank Kannenberg
- From the Center for Laboratory Medicine, University of Münster, 48149 Münster, Germany
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17
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Dasari B, Prasanthi JRP, Meiers C, Singh BB, Ghribi O. Differential effects of the estrogen receptor agonist estradiol on toxicity induced by enzymatically-derived or autoxidation-derived oxysterols in human ARPE-19 cells. Curr Eye Res 2013; 38:1159-71. [PMID: 23841471 DOI: 10.3109/02713683.2013.811257] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
PURPOSE/AIM OF THE STUDY Disturbances in cholesterol metabolism and increased levels of cholesterol oxidation products (oxysterols) in retina may contribute to age-related macular degeneration (AMD). The role of oxysterols or of their target receptors liver X receptors (LXRs) and estrogen receptors (ERs) in the pathogenesis of MD is ill-known. The purpose of this study is to determine the extent to which the oxysterols 27-hydroxycholesterol (27-OHC), 25-hydroxycholesterol (25-OHC) and 7-ketocholesterol (7-KC) affect the transcriptional activity of LXR and ER. MATERIALS AND METHODS ARPE-19 cells, untreated or incubated with 27-OHC, 25-OHC or 7-KC for 24 h were harvested. We used Western blot analyses for detecting ERs and LXRs expression, dual luciferase assays for measuring LXRs and ERs transcriptional activity, cytotox-ONE homogeneous membrane integrity assay for measuring cytotoxicity, JC-1 method for measuring mitochondrial membrane potential changes and ELISA for measuring cytokine levels. RESULTS Both LXRs and ERs are expressed and are transcriptionally active in ARPE-19 cells. 27-OHC, 25-OHC and 7-KC inhibited ER-mediated transcriptional activity, whereas 27-OHC and 25-OHC increased LXR-mediated transcription. E2 reduced 25-OHC and 27-OHC-induced cytotoxicity, mitochondrial permeability potential decline, and cytokine secretion. The LXR agonist GW3965 or the LXR antagonist 5α-6α-epoxycholesterol-3-sulfate (ECHS) did not offer protection against either 27-OHC and 25-OHC or 7-KC. CONCLUSIONS Increased levels of oxysterols can decrease ER and increase LXR signaling. ER agonists can offer protection against cytotoxic effects of 27-OHC and 25-OHC, two oxysterols derived by enzymatic reactions. Although they exert similar toxicity, the cellular mechanisms involved in the toxic effects of oxysterols whether derived by enzymatic or autoxidation reactions appear to be different.
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Affiliation(s)
- Bhanu Dasari
- Department of Pharmacology, Physiology and Therapeutics and
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18
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Hashimoto M, Kobayashi K, Watanabe M, Kazuki Y, Takehara S, Inaba A, Nitta SI, Senda N, Oshimura M, Chiba K. Knockout of mouse Cyp3a gene enhances synthesis of cholesterol and bile acid in the liver. J Lipid Res 2013; 54:2060-2068. [PMID: 23709690 DOI: 10.1194/jlr.m033464] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Here, we studied the effects of cytochrome P450 (CYP)3A deficiency on the mRNA expression of genes encoding regulators of hepatic cholesterol levels using Cyp3a-knockout (Cyp3a(-/-)) mice. The mRNA expression levels of genes encoding enzymes involved in cholesterol biosynthesis in the livers of Cyp3a(-/-) mice were higher than those of wild-type (WT) mice. Nuclear levels of sterol regulatory element-binding protein-2 (SREBP-2), which enhances cholesterol biosynthesis, were also higher in the livers of Cyp3a(-/-) mice. Binding of SREBP-2 to the Hmgcs1 gene promoter was more abundant in the livers of Cyp3a(-/-) mice. These results suggest that deficiency of CYP3A enzymes enhances transcription of genes encoding enzymes involved in cholesterol biosynthesis via activation of SREBP-2. On the other hand, hepatic cholesterol levels in Cyp3a(-/-) mice were 20% lower than those in WT mice. The mRNA expression levels of genes encoding enzymes involved in bile acid synthesis, plasma levels of 7α-hydroxy-4-cholesten-3-one and hepatic levels of total bile acid were significantly higher in Cyp3a(-/-) mice than in WT mice. These findings suggest that reduction of hepatic total cholesterol in Cyp3a(-/-) mice would be the consequence of enhanced bile acid synthesis. Therefore, CYP3A enzymes appear to play roles in the synthesis of cholesterol and bile acid in vivo.
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Affiliation(s)
- Mari Hashimoto
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 260-8675, Japan
| | - Kaoru Kobayashi
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 260-8675, Japan
| | - Mio Watanabe
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 260-8675, Japan
| | - Yasuhiro Kazuki
- Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, Tottori 683-8503, Japan; Chromosome Engineering Research Center (CERC), Tottori University, Tottori 683-8503, Japan
| | - Shoko Takehara
- Chromosome Engineering Research Center (CERC), Tottori University, Tottori 683-8503, Japan
| | - Asumi Inaba
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 260-8675, Japan
| | - Shin-Ichiro Nitta
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 260-8675, Japan; Mitsubishi Chemical Medience Corporation, Ibaraki 305-0047, Japan
| | - Naoto Senda
- Mitsubishi Chemical Medience Corporation, Ibaraki 305-0047, Japan
| | - Mitsuo Oshimura
- Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, Tottori 683-8503, Japan; Chromosome Engineering Research Center (CERC), Tottori University, Tottori 683-8503, Japan
| | - Kan Chiba
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 260-8675, Japan
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19
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Pannu PS, Allahverdian S, Francis GA. Oxysterol generation and liver X receptor-dependent reverse cholesterol transport: not all roads lead to Rome. Mol Cell Endocrinol 2013; 368:99-107. [PMID: 22884520 DOI: 10.1016/j.mce.2012.07.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 06/30/2012] [Accepted: 07/27/2012] [Indexed: 12/31/2022]
Abstract
Cell cholesterol metabolism is a tightly regulated process, dependent in part on activation of nuclear liver X receptors (LXRs) to increase expression of genes mediating removal of excess cholesterol from cells in the reverse cholesterol transport pathway. LXRs are thought to be activated predominantly by oxysterols generated enzymatically from cholesterol in different cell organelles. Defects resulting in slowed release of cholesterol from late endosomes and lysosomes or reduction in sterol-27-hydroxylase activity lead to specific blocks in oxysterol production and impaired LXR-dependent gene activation. This block does not appear to be compensated by oxysterol production in other cell compartments. The purpose of this review is to summarize current knowledge about oxysterol-dependent activation by LXR of genes involved in reverse cholesterol transport, and what these defects of cell cholesterol homeostasis can teach us about the critical pathways of oxysterol generation for expression of LXR-dependent genes.
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Affiliation(s)
- Parveer S Pannu
- Department of Medicine, UBC James Hogg Research Centre, Institute of Heart and Lung Health at St. Paul's Hospital, Vancouver, BC, Canada V6Z 1Y6.
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20
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Abstract
Cholesterol trafficking from the outer to the cholesterol-poor inner mitochondrial membrane requires energized, polarized and actively respiring mitochondria, mediated by a highly regulated multimeric (140-200 kDa) protein complex comprising StAR (steroidogenic acute regulatory protein), mitochondrial TSPO (translocator protein), VDAC (voltage-dependent anion channel), ANT (adenine nucleotide transporter) and associated regulatory proteins. Mitochondrial cholesterol transport is rate-limiting in the CYP27A1 (sterol 27-hydroxylase)-dependent generation of oxysterol ligands for LXR (liver X receptor) transcription factors that regulate the expression of genes encoding proteins in the cholesterol efflux pathway, such as ABC transporters (ATP-binding cassette transporters) ABCA1 and ABCG1. These transporters transfer cholesterol and/or phospholipids across the plasma membrane to (apo)lipoprotein acceptors, generating nascent HDLs (high-density lipoproteins), which can safely transport excess cholesterol through the bloodstream to the liver for excretion in bile. Utilizing information from steroidogenic tissues, we propose that perturbations in mitochondrial function may reduce the efficiency of the cholesterol efflux pathway, favouring accumulation of cholesteryl ester 'foam cells' and allowing the toxic accumulation of free cholesterol at the interface between the endoplasmic reticulum and the mitochondrial membrane. In turn, this will trigger opening of the permeability transition pore, allowing unregulated production of oxysterols via CYP27A1, allowing the accumulation of esterified forms of this oxysterol within human atherosclerotic lesions. Defective cholesterol efflux also induces endoplasmic reticulum stress, proteasomal degradation of ABCA1 and Fas-dependent apoptosis, replicating findings in macrophages in advanced atherosclerotic lesions. Small molecules targeted to mitochondria, capable of sustaining mitochondrial function or improving cholesterol trafficking may aid cholesterol efflux from macrophage 'foam' cells, regressing and stabilizing the atherosclerotic plaque.
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21
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On the formation and possible biological role of 25-hydroxycholesterol. Biochimie 2013; 95:455-60. [DOI: 10.1016/j.biochi.2012.06.016] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 06/14/2012] [Indexed: 11/22/2022]
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22
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Ali Z, Heverin M, Olin M, Acimovic J, Lövgren-Sandblom A, Shafaati M, Båvner A, Meiner V, Leitersdorf E, Björkhem I. On the regulatory role of side-chain hydroxylated oxysterols in the brain. Lessons from CYP27A1 transgenic and Cyp27a1(-/-) mice. J Lipid Res 2013; 54:1033-43. [PMID: 23284090 DOI: 10.1194/jlr.m034124] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The two oxysterols, 27-hydroxycholesterol (27OH) and 24S-hydroxycholesterol (24OH), are both inhibitors of cholesterol synthesis and activators of the liver X receptor (LXR) in vitro. Their role as physiological regulators under in vivo conditions is controversial, however. In the present work, we utilized a previously described mouse model with overexpressed human sterol 27-hydroxylase (CYP27A1). The levels of 27OH were increased about 12-fold in the brain. The brain levels of HMG-CoA reductase mRNA and HMG-CoA synthase mRNA levels were increased. In accordance with increased cholesterol synthesis, most of the cholesterol precursors were also increased. The level of 24OH, the dominating oxysterol in the brain, was decreased by about 25%, most probably due to increased metabolism by CYP27A1. The LXR target genes were unaffected or slightly changed in a direction opposite to that expected for LXR activation. In the brain of Cyp27(-/-) mice, cholesterol synthesis was slightly increased, with increased levels of cholesterol precursors but normal mRNA levels of HMG-CoA reductase and HMG-CoA synthase. The mRNA levels corresponding to LXR target genes were not affected. The results are consistent with the possibility that both 24OH and 27OH are physiological suppressors of cholesterol synthesis in the brain. The results do not support the contention that 27OH is a general activator of LXR target genes in this organ.
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Affiliation(s)
- Zeina Ali
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institute, Sweden
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23
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Meljon A, Theofilopoulos S, Shackleton CHL, Watson GL, Javitt NB, Knölker HJ, Saini R, Arenas E, Wang Y, Griffiths WJ. Analysis of bioactive oxysterols in newborn mouse brain by LC/MS. J Lipid Res 2012; 53:2469-83. [PMID: 22891291 DOI: 10.1194/jlr.d028233] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Unesterified cholesterol is a major component of plasma membranes. In the brain of the adult, it is mostly found in myelin sheaths, where it plays a major architectural role. In the newborn mouse, little myelination of neurons has occurred, and much of this sterol comprises a metabolically active pool. In the current study, we have accessed this metabolically active pool and, using LC/MS, have identified cholesterol precursors and metabolites. Although desmosterol and 24S-hydroxycholesterol represent the major precursor and metabolite, respectively, other steroids, including the oxysterols 22-oxocholesterol, 22R-hydroxycholesterol, 20R,22R-dihydroxycholesterol, and the C(21)-neurosteroid progesterone, were identified. 24S,25-epoxycholesterol formed in parallel to cholesterol was also found to be a major sterol in newborn brain. Like 24S- and 22R-hydroxycholesterols, and also desmosterol, 24S,25-epoxycholesterol is a ligand to the liver X receptors, which are expressed in brain. The desmosterol metabolites (24Z),26-, (24E),26-, and 7α-hydroxydesmosterol were identified in brain for the first time.
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Affiliation(s)
- Anna Meljon
- Institute of Mass Spectrometry, College of Medicine, Swansea, UK
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24
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Hannedouche S, Zhang J, Yi T, Shen W, Nguyen D, Pereira JP, Guerini D, Baumgarten BU, Roggo S, Wen B, Knochenmuss R, Noël S, Gessier F, Kelly LM, Vanek M, Laurent S, Preuss I, Miault C, Christen I, Karuna R, Li W, Koo DI, Suply T, Schmedt C, Peters EC, Falchetto R, Katopodis A, Spanka C, Roy MO, Detheux M, Chen YA, Schultz PG, Cho CY, Seuwen K, Cyster JG, Sailer AW. Oxysterols direct immune cell migration via EBI2. Nature 2011; 475:524-7. [PMID: 21796212 PMCID: PMC4297623 DOI: 10.1038/nature10280] [Citation(s) in RCA: 352] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 06/09/2011] [Indexed: 12/20/2022]
Abstract
Epstein-Barr virus-induced gene 2 (EBI2, also known as GPR183) is a G-protein-coupled receptor that is required for humoral immune responses; polymorphisms in the receptor have been associated with inflammatory autoimmune diseases. The natural ligand for EBI2 has been unknown. Here we describe the identification of 7α,25-dihydroxycholesterol (also called 7α,25-OHC or 5-cholesten-3β,7α,25-triol) as a potent and selective agonist of EBI2. Functional activation of human EBI2 by 7α,25-OHC and closely related oxysterols was verified by monitoring second messenger readouts and saturable, high-affinity radioligand binding. Furthermore, we find that 7α,25-OHC and closely related oxysterols act as chemoattractants for immune cells expressing EBI2 by directing cell migration in vitro and in vivo. A critical enzyme required for the generation of 7α,25-OHC is cholesterol 25-hydroxylase (CH25H). Similar to EBI2 receptor knockout mice, mice deficient in CH25H fail to position activated B cells within the spleen to the outer follicle and mount a reduced plasma cell response after an immune challenge. This demonstrates that CH25H generates EBI2 biological activity in vivo and indicates that the EBI2-oxysterol signalling pathway has an important role in the adaptive immune response.
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Affiliation(s)
| | - Juan Zhang
- Analytical Sciences; Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Tangsheng Yi
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California San Francisco, CA, USA
| | - Weijun Shen
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
| | - Deborah Nguyen
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - João P. Pereira
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California San Francisco, CA, USA
| | - Danilo Guerini
- Autoimmunity, Transplantation and Inflammation; Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Birgit U. Baumgarten
- Developmental and Molecular Pathways; Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Silvio Roggo
- Global Discovery Chemistry; Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Ben Wen
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Richard Knochenmuss
- Analytical Sciences; Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Francois Gessier
- Global Discovery Chemistry; Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Lisa M. Kelly
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California San Francisco, CA, USA
| | - Mirka Vanek
- Developmental and Molecular Pathways; Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Stephane Laurent
- Developmental and Molecular Pathways; Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Inga Preuss
- Developmental and Molecular Pathways; Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Charlotte Miault
- Global Discovery Chemistry; Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Isabelle Christen
- Analytical Sciences; Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Ratna Karuna
- Analytical Sciences; Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Wei Li
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Dong-In Koo
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
| | - Thomas Suply
- Developmental and Molecular Pathways; Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Christian Schmedt
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Eric C. Peters
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Rocco Falchetto
- Analytical Sciences; Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Andreas Katopodis
- Autoimmunity, Transplantation and Inflammation; Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Carsten Spanka
- Global Discovery Chemistry; Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | | | - Yu Alice Chen
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Peter G. Schultz
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Charles Y. Cho
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Klaus Seuwen
- Developmental and Molecular Pathways; Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Jason G. Cyster
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California San Francisco, CA, USA
| | - Andreas W. Sailer
- Developmental and Molecular Pathways; Novartis Institutes for BioMedical Research, Basel, Switzerland
- Corresponding author: Andreas W. Sailer, Ph. D. Developmental & Molecular Pathways Novartis Institutes for BioMedical Research Forum 1, Novartis Campus, WSJ-355.4.025.8 4056 Basel, Switzerland Phone: +41 79 5500941 Fax: +41 61 6968714
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25
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Pathways of cholesterol oxidation via non-enzymatic mechanisms. Chem Phys Lipids 2011; 164:457-68. [PMID: 21703250 DOI: 10.1016/j.chemphyslip.2011.06.006] [Citation(s) in RCA: 191] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 05/12/2011] [Accepted: 06/08/2011] [Indexed: 12/31/2022]
Abstract
Cholesterol has many functions, including those that affect biophysical properties of membranes, and is a precursor to hormone synthesis. These actions are governed by enzymatic pathways that modify the sterol nucleus or the isooctyl tail. The addition of oxygen to the cholesterol backbone produces its derivatives known as oxysterols. In addition to having an enzymatic origin, oxysterols can be formed in the absence of enzymatic catalysis in a pathway usually termed "autoxidation," which has been known for almost a century and observed under various experimental conditions. Autoxidation of cholesterol can occur through reactions initiated by free radical species, such as those arising from the superoxide/hydrogen peroxide/hydroxyl radical system and by non-radical highly reactive oxygen species such as singlet oxygen, HOCl, and ozone. The susceptibility of cholesterol to non-enzymatic oxidation has raised considerable interest in the function of oxysterols as biological effectors and potential biomarkers for the non-invasive study of oxidative stress in vivo.
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26
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Diczfalusy U, Björkhem I. Still another activity by the highly promiscuous enzyme CYP3A4: 25-hydroxylation of cholesterol. J Lipid Res 2011; 52:1447-9. [PMID: 21652732 DOI: 10.1194/jlr.e017806] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Ulf Diczfalusy
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden
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27
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Honda A, Miyazaki T, Ikegami T, Iwamoto J, Maeda T, Hirayama T, Saito Y, Teramoto T, Matsuzaki Y. Cholesterol 25-hydroxylation activity of CYP3A. J Lipid Res 2011; 52:1509-16. [PMID: 21576599 DOI: 10.1194/jlr.m014084] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To date, many studies have been conducted using 25-hydroxycholesterol, which is a potent regulator of lipid metabolism. However, the origins of this oxysterol have not been entirely elucidated. Cholesterol 25-hydroxylase is one of the enzymes responsible for the metabolism of 25-hydroxycholesterol, but the expression of this enzyme is very low in humans. This oxysterol is also synthesized by sterol 27-hydroxylase (CYP27A1) and cholesterol 24-hydroxylase(CYP46A1), but it is only a minor product of these enzymes. We now report that CYP3A synthesizes a significant amount of 25-hydroxycholesterol and may participate in the regulation of lipid metabolism. Induction of CYP3A by pregnenolone-16α-carbonitrile caused the accumulation of 25-hydroxycholesterol in a cell line derived from mouse liver. Furthermore, treatment of the cells with troleandomycin, a specific inhibitor of CYP3A, significantly reduced cellular 25-hydroxycholesterol concentrations. In cells that overexpressed human recombinant CYP3A4, the activity of cholesterol 25-hydroxylation was found to be higher than that of cholesterol 4β-hydroxylation, a known marker activity of CYP3A4. In addition, 25-hydroxycholesterol concentrations in normal human sera correlated positively with the levels of 4β-hydroxycholesterol (r = 0.650, P < 0.0001, n = 78), but did not significantly correlate with the levels of 27-hydroxycholesterol or 24S-hydroxycholesterol. These results demonstrate the significance of CYP3A on the production of 25-hydroxycholesterol.
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Affiliation(s)
- Akira Honda
- Department of Gastroenterology, Center for Collaborative Research, Ibaraki 300-0395, Japan
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28
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Listeria monocytogenes infection induces prosurvival metabolic signaling in macrophages. Infect Immun 2011; 79:1526-35. [PMID: 21263022 DOI: 10.1128/iai.01195-10] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Host cells use metabolic signaling through the LXRα nuclear receptor to defend against Listeria monocytogenes infection. 25-Hydroxycholesterol is a natural ligand of LXRs that is produced by the enzyme cholesterol 25-hydroxylase (CH25H). We found that expression of Ch25h is upregulated following L. monocytogenes infection in a beta interferon (IFN-β)-dependent fashion. Moreover, increased Ch25h expression promotes survival of L. monocytogenes-infected cells and increases sensitivity of the host to infection. We determined that expression of Cd5l, a prosurvival gene, is controlled by CH25H. In addition, we found that CD5L inhibits activation of caspase-1, promoting survival of infected macrophages. Our results reveal a mechanism by which an intracellular pathogen can prolong survival of infected cells, thus providing itself with a protected environment in which to replicate.
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29
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24S-hydroxycholesterol effects on lipid metabolism genes are modeled in traumatic brain injury. Brain Res 2010; 1319:1-12. [PMID: 20053345 DOI: 10.1016/j.brainres.2009.12.080] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 12/16/2009] [Accepted: 12/23/2009] [Indexed: 12/22/2022]
Abstract
Membrane damage during traumatic brain injury (TBI) alters the brain homeostasis of cholesterol and other lipids. Cholesterol 24S-hydroxylase (Cyp46) is a cholesterol metabolic enzyme that is increased after TBI. Here, we systematically examined the effects of the enzymatic product of Cyp46, 24S-hydroxycholesterol, on the cholesterol regulatory genes, SREBP-1 and 2, their posttranslational regulation, and their effects on gene transcription. 24S-hydroxycholesterol increased levels of SREBP-1 mRNA and full-length protein but did not change levels of cleaved SREBP-1, consistent with the role of 24-hydroxycholesterol as an LXR agonist. In contrast, 24S-hydroxycholesterol decreased levels of LXR-independent SREBP-2 mRNA, full-length protein, and SREBP-2 active cleavage product. We examined the downstream effects of changes to these lipid regulatory factors by studying cholesterol and fatty acid synthesis genes. In neuroblastoma cells, 24S-hydroxycholesterol decreased mRNA levels of the cholesterol synthesis genes HMG CoA reductase, squalene synthase, and FPP synthase but did not alter levels of the mRNA of fatty acid synthesis genes acetyl CoA carboxylase or fatty acid synthase. After TBI, as after 24S-hydroxycholesterol treatment in vitro, SREBP-1 mRNA levels were increased while SREBP-2 mRNA levels were decreased. Also similar to the in vitro results with 24S-hydroxycholesterol, HMG CoA reductase and squalene synthase mRNA levels were significantly decreased. Fatty acid synthase mRNA levels were not altered but acetyl CoA carboxylase mRNA levels were significantly decreased. Thus, changes to transcription of cholesterol synthesis genes after TBI were consistent with increases in Cyp46 activity, but changes to fatty acid synthesis genes must be regulated by other mechanisms.
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30
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Russell DW, Halford RW, Ramirez DMO, Shah R, Kotti T. Cholesterol 24-hydroxylase: an enzyme of cholesterol turnover in the brain. Annu Rev Biochem 2009; 78:1017-40. [PMID: 19489738 DOI: 10.1146/annurev.biochem.78.072407.103859] [Citation(s) in RCA: 216] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cholesterol 24-hydroxylase is a highly conserved cytochrome P450 that is responsible for the majority of cholesterol turnover in the vertebrate central nervous system. The enzyme is expressed in neurons, including hippocampal and cortical neurons that are important for learning and memory formation. Disruption of the cholesterol 24-hydroxylase gene in the mouse reduces both cholesterol turnover and synthesis in the brain but does not alter steady-state levels of cholesterol in the tissue. The decline in synthesis reduces the flow of metabolites through the cholesterol biosynthetic pathway, of which one, geranylgeraniol diphosphate, is required for learning in the whole animal and for synaptic plasticity in vitro. This review focuses on how the link between cholesterol metabolism and higher-order brain function was experimentally established.
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Affiliation(s)
- David W Russell
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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31
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Diczfalusy U, Olofsson KE, Carlsson AM, Gong M, Golenbock DT, Rooyackers O, Fläring U, Björkbacka H. Marked upregulation of cholesterol 25-hydroxylase expression by lipopolysaccharide. J Lipid Res 2009; 50:2258-64. [PMID: 19502589 DOI: 10.1194/jlr.m900107-jlr200] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
During screening of genes upregulated by lipopolysaccharide (LPS; endotoxin) treatment of bone marrow-derived mouse macrophages, it was unexpectedly found that cholesterol 25-hydroxylase (Ch25h) was strongly upregulated. Treatment of macrophages with 10 ng/ml of LPS for 2 h resulted in a 35-fold increase in the expression of Ch25h. In contrast, LPS treatment did not increase the expression of Cyp27a1 or Cyp7b1. The increased Ch25h expression was found to be independent of Myeloid differentiation protein 88 signaling but dependent on Toll-like receptor 4 signaling. LPS treatment of macrophages caused a 6- to 7-fold increase in cellular 25-hydroxycholesterol concentration. When macrophages were treated with increasing concentrations of 25-hydroxycholesterol, a dose-dependent release of CCL5 into the culture medium was observed. Intravenous injection of LPS in eight healthy volunteers resulted in an increase in plasma 25-hydroxycholesterol concentration. The possibility is discussed that 25-hydroxycholesterol may have a role in the inflammatory response, in addition to its more established role in the regulation of cholesterol homeostasis.
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Affiliation(s)
- Ulf Diczfalusy
- Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden
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32
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Alnouti Y. Bile Acid sulfation: a pathway of bile acid elimination and detoxification. Toxicol Sci 2009; 108:225-46. [PMID: 19131563 DOI: 10.1093/toxsci/kfn268] [Citation(s) in RCA: 277] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Sulfotransferase-2A1 catalyzes the formation of bile acid-sulfates (BA-sulfates). Sulfation of BAs increases their solubility, decreases their intestinal absorption, and enhances their fecal and urinary excretion. BA-sulfates are also less toxic than their unsulfated counterparts. Therefore, sulfation is an important detoxification pathway of BAs. Major species differences in BA sulfation exist. In humans, only a small proportion of BAs in bile and serum are sulfated, whereas more than 70% of BAs in urine are sulfated, indicating their efficient elimination in urine. The formation of BA-sulfates increases during cholestatic diseases. Therefore, sulfation may play an important role in maintaining BA homeostasis under pathologic conditions. Farnesoid X receptor, pregnane X receptor, constitutive androstane receptor, and vitamin D receptor are potential nuclear receptors that may be involved in the regulation of BA sulfation. This review highlights current knowledge about the enzymes and transporters involved in the formation and elimination of BA-sulfates, the effect of sulfation on the pharmacologic and toxicologic properties of BAs, the role of BA sulfation in cholestatic diseases, and the regulation of BA sulfation.
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Affiliation(s)
- Yazen Alnouti
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198, USA
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33
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Li X, Pandak WM, Erickson SK, Ma Y, Yin L, Hylemon P, Ren S. Biosynthesis of the regulatory oxysterol, 5-cholesten-3beta,25-diol 3-sulfate, in hepatocytes. J Lipid Res 2007; 48:2587-96. [PMID: 17890683 DOI: 10.1194/jlr.m700301-jlr200] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cellular cholesterol homeostasis is maintained through coordinated regulation of cholesterol synthesis, degradation, and secretion. Nuclear receptors for oxygenated cholesterol derivatives (oxysterols) are known to play key roles in the regulation of cholesterol homeostasis. We recently identified a sulfated oxysterol, 5-cholesten-3beta,25-diol 3-sulfate (25HC3S), that is localized to liver nuclei. The present study reports a biosynthetic pathway for 25HC3S in hepatocytes. Assays using mitochondria isolated from rats and sterol 27-hydroxylase (Cyp27A1) gene knockout mice indicated that 25-hydroxycholesterol (25HC) is synthesized by CYP27A1. Incubation of cholesterol or 25HC with mitochondrial and cytosolic fractions in the presence of 3'-phosphoadenosyl 5'-phosphosulfate resulted in the synthesis of 25HC3S. Real-time RT-PCR and Western blot analysis showed the presence of insulin-regulated hydroxycholesterol sulfotransferase 2B1b (SULT2B1b) in hepatocytes. 25HC3S, but not 25HC, decreased SULT2B1b mRNA and protein levels. Specific small interfering RNA decreased SULT2B1b mRNA, protein, and activity levels. These findings demonstrate that mitochondria synthesize 25HC, which is subsequently 3beta-sulfated to form 25HC3S.
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Affiliation(s)
- Xiaobo Li
- Department of Medicine Veterans Affairs McGuire Medical Center, Virginia Commonwealth University, Richmond, VA 23249, USA
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34
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Abstract
During the last three to four decades there has been an increasing interest in the interaction of circulating and brain cholesterol. Recent in vivo and in vitro studies have furthered our knowledge of cholesterol metabolism in the central nervous system (CNS). As the CNS matures and cholesterol pools in the brain become constant, the rate of de novo synthesis of cholesterol in the brain markedly declines. Besides some excretion of apoE-bound cholesterol via the CSF, another quantitatively more important mechanism has been described - the conversion of cholesterol into 24S-hydroxycholesterol, that is, in contrast to cholesterol, able to traverse the blood-brain barrier (BBB). The enzyme (CYP46a1) mediating this conversion has been characterized at the molecular level and is mainly located in neurons. Like other oxysterols, 24S-hydroxycholesterol is efficiently converted into normal bile acids or excreted in bile in its sulfated and glucuronidated form. Within the last 10 years the interest in studying the mechanisms of this and other cholesterol transport systems has increased and the results from these in vivo and in vitro investigations are reviewed.
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Affiliation(s)
- D Lütjohann
- Department of Clinical Pharmacology, University of Bonn, Germany.
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35
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Davies L, Williams DR, Turner PC, Rees HH. Characterization in relation to development of an ecdysteroid agonist-responsive cytochrome P450, CYP18A1, in Lepidoptera. Arch Biochem Biophys 2006; 453:4-12. [PMID: 16884680 DOI: 10.1016/j.abb.2006.06.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Revised: 06/06/2006] [Accepted: 06/15/2006] [Indexed: 11/28/2022]
Abstract
Cytochrome P450 enzymes are involved in a number of steps in ecdysteroid (moulting hormone) homeostasis in insects. We report the cloning and characterization of an ecdysteroid agonist-responsive cytochrome P450, CYP18A1, from the cotton leafworm, Spodoptera littoralis. Northern blot analysis showed that the mRNA transcript was expressed at times of increasing ecdysteroid titre in final instar S. littoralis larvae and was induced by the ecdysteroid receptor agonist, RH-5992, in midgut and fat body. In addition, transcript expression was also detected in the prothoracic glands, a major ecdysteroid biosynthetic tissue, in both S. littoralis and the tobacco hornworm, Manduca sexta, at a time of increasing ecdysteroid titre. The exact significance of the temporal and spatial expression of CYP18A1 is unclear. The characterization of a P450 that is ecdysteroid agonist-responsive may provide a future target for exploitation in the development of novel insect control strategies.
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Affiliation(s)
- Lyndsay Davies
- Cell Regulation and Signalling Division, School of Biological Sciences, University of Liverpool, Biosciences Building, Crown Street, Liverpool, L69 7ZB, UK
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36
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Murtazina DA, Andersson U, Hahn IS, Bjorkhem I, Ansari GAS, Pikuleva IA. Phospholipids modify substrate binding and enzyme activity of human cytochrome P450 27A1. J Lipid Res 2004; 45:2345-53. [PMID: 15342675 DOI: 10.1194/jlr.m400300-jlr200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cytochrome P450 27A1 (P450 27A1) is an important metabolic enzyme involved in bile acid biosynthesis and the activation of vitamin D3 in mammals. Recombinant P450 27A1 heterologously expressed in Escherichia coli was found to be copurified with phospholipids (PLs). The PL content varied in different preparations and was dependent on the purification protocol. A link between the increased amounts of PLs and deterioration of the enzyme substrate binding properties was also observed. Tandem negative ionization mass spectrometry identified phosphatidylglycerol (PG) as the major PL copurified with P450 27A1. Subsequent reconstitution of P450 into exogenous PG vesicles assessed the effect of this contamination on substrate binding and enzyme activity. Two other PLs, phosphatidylethanolamine (PE) and phosphatidylserine (PS), were also tested. PG and PE increased the Kd for 5beta-cholestane-3alpha,7alpha,12alpha-triol and cholesterol binding, whereas PS had no effect on either substrate binding. PG and PE did not significantly alter 5beta-cholestane-3alpha,7alpha,12alpha-triol hydroxylase activity and even stimulated cholesterol hydroxylase activity. PS inhibited 5beta-cholestane-3alpha,7alpha,12alpha-triol hydrolyase activity and had no effect on cholesterol hydroxylase activity. Our study shows the potential for PLs to regulate the activity of P450 27A1 in vivo and alter the amount of cholesterol degraded through the "classical" and "alternative" bile acid biosynthetic pathways.
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Affiliation(s)
- Dilyara A Murtazina
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555-1031, USA
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37
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Zhang J, Dudley-Rucker N, Crowley JR, Lopez-Perez E, Issandou M, Schaffer JE, Ory DS. The steroidal analog GW707 activates the SREBP pathway through disruption of intracellular cholesterol trafficking. J Lipid Res 2004; 45:223-31. [PMID: 14617742 DOI: 10.1194/jlr.m300409-jlr200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recently, a new class of lipid-lowering agents has been described that upregulate LDL receptor (LDLr) activity. These agents are proposed to activate sterol-regulated gene expression through binding to the sterol regulatory element binding protein (SREBP) cleavage-activating protein (SCAP). Here, we show that the steroidal LDLr upregulator, GW707, induces accumulation of lysosomal free cholesterol and inhibits LDL-stimulated cholesterol esterification, similar to that observed in U18666A-treated cells and in Niemann-Pick type C1 (NPC1) mutants. Moreover, we demonstrate that induction of the NPC-like phenotype by GW707 is independent of SCAP function. We find that treatment with GW707 does not increase SREBP-dependent gene expression above that observed in lipoprotein-starved cells. Rather, we show that the apparent increase in SREBP-dependent activity in GW707-treated cells is attributable to a failure to appropriately suppress sterol-regulated gene expression, as has been shown previously for U18666A-treated cells and NPC mutant fibroblasts. We further demonstrate that cells treated with either GW707 or U18666A fail to appropriately generate 27-hydroxycholesterol in response to LDL cholesterol. Taken together, these findings support a mechanism in which GW707 exerts its hypolipidemic effects through disruption of late endosomal/lysosomal sterol trafficking and subsequent stimulation of LDLr activity.
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Affiliation(s)
- Jessie Zhang
- Center for Cardiovascular Research, 91951 Les Ulis, France
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38
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Abstract
The synthesis and excretion of bile acids comprise the major pathway of cholesterol catabolism in mammals. Synthesis provides a direct means of converting cholesterol, which is both hydrophobic and insoluble, into a water-soluble and readily excreted molecule, the bile acid. The biosynthetic steps that accomplish this transformation also confer detergent properties to the bile acid, which are exploited by the body to facilitate the secretion of cholesterol from the liver. This role in the elimination of cholesterol is counterbalanced by the ability of bile acids to solubilize dietary cholesterol and essential nutrients and to promote their delivery to the liver. The synthesis of a full complement of bile acids requires 17 enzymes. The expression of selected enzymes in the pathway is tightly regulated by nuclear hormone receptors and other transcription factors, which ensure a constant supply of bile acids in an ever changing metabolic environment. Inherited mutations that impair bile acid synthesis cause a spectrum of human disease; this ranges from liver failure in early childhood to progressive neuropathy in adults.
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Affiliation(s)
- David W Russell
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9046, USA.
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Lund EG, Xie C, Kotti T, Turley SD, Dietschy JM, Russell DW. Knockout of the cholesterol 24-hydroxylase gene in mice reveals a brain-specific mechanism of cholesterol turnover. J Biol Chem 2003; 278:22980-8. [PMID: 12686551 DOI: 10.1074/jbc.m303415200] [Citation(s) in RCA: 302] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Most cholesterol turnover takes place in the liver and involves the conversion of cholesterol into soluble and readily excreted bile acids. The synthesis of bile acids is limited to the liver, but several enzymes in the bile acid biosynthetic pathway are expressed in extra-hepatic tissues and there also may contribute to cholesterol turnover. An example of the latter type of enzyme is cholesterol 24-hydroxylase, a cytochrome P450 (CYP46A1) that is expressed at 100-fold higher levels in the brain than in the liver. Cholesterol 24-hydroxylase catalyzes the synthesis of the oxysterol 24(S)-hydroxycholesterol. To assess the relative contribution of the 24-hydroxylation pathway to cholesterol turnover, we performed balance studies in mice lacking the cholesterol 24-hydroxylase gene (Cyp46a1-/- mice). Parameters of hepatic cholesterol and bile acid metabolism in the mutant mice remained unchanged relative to wild type controls. In contrast to the liver, the synthesis of new cholesterol was reduced by approximately 40% in the brain, despite steady-state levels of cholesterol being similar in the knockout mice. These data suggest that the synthesis of new cholesterol and the secretion of 24(S)-hydroxycholesterol are closely coupled and that at least 40% of cholesterol turnover in the brain is dependent on the action of cholesterol 24-hydroxylase. We conclude that cholesterol 24-hydroxylase constitutes a major tissue-specific pathway for cholesterol turnover in the brain.
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Affiliation(s)
- Erik G Lund
- Department of Molecular Genetics, The University of Texas Southwestern Medical Center, Dallas, Texas 75390-9046, USA
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40
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Sinal CJ, Yoon M, Gonzalez FJ. Antagonism of the actions of peroxisome proliferator-activated receptor-alpha by bile acids. J Biol Chem 2001; 276:47154-62. [PMID: 11606578 DOI: 10.1074/jbc.m107000200] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The peroxisome proliferator-activated receptor-alpha (PPARalpha) is a ligand-activated transcription factor that regulates the expression of a number of genes critical for fatty acid beta-oxidation. Because a number of substrates and intermediates of this metabolic pathway serve as ligand activators of this receptor, homeostatic control of fatty acid metabolism is achieved. Evidence also exists for PPARalpha-dependent regulation of genes encoding critical enzymes of bile acid biosynthesis. To determine whether the primary products of bile acid biosynthesis, cholic acid and chenodeoxycholic acid, were capable of modulating PPARalpha function, a variety of in vivo and in vitro approaches were utilized. Feeding a bile acid-enriched diet significantly reduced the degree of hepatomegaly and induction of target genes encoding enzymes of fatty acid beta-oxidation caused by treatment with the potent PPARalpha ligand Wyeth-14,643. Convergent data from mechanistic studies indicate that bile acids interfere with transactivation by PPARalpha at least in part by impairing the recruitment of transcriptional coactivators. The results of this study provide the first evidence in favor of the existence of compounds, normally found within the body, that are capable of antagonizing the physiological actions of PPARalpha. The impact of PPARalpha antagonism by endogenous bile acids is likely to be limited under normal conditions and to have only minimal effects on bile acid homeostasis. However, during certain pathophysiological states where intracellular bile acid concentrations are elevated, meaningful effects on PPARalpha-dependent target gene regulation are possible.
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Affiliation(s)
- C J Sinal
- Laboratory of Metabolism, Division of Basic Sciences, NCI, National Institutes of Health, Bethesda, MD 20892, USA
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41
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Honda A, Salen G, Matsuzaki Y, Batta AK, Xu G, Leitersdorf E, Tint GS, Erickson SK, Tanaka N, Shefer S. Side chain hydroxylations in bile acid biosynthesis catalyzed by CYP3A are markedly up-regulated in Cyp27-/- mice but not in cerebrotendinous xanthomatosis. J Biol Chem 2001; 276:34579-85. [PMID: 11454857 DOI: 10.1074/jbc.m103025200] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The accumulation of various 25-hydroxylated C(27)-bile alcohols in blood and their excretion in urine are characteristic features of cerebrotendinous xanthomatosis (CTX) a recessively inherited inborn error of bile acid synthesis caused by mutations in the mitochondrial sterol 27-hydroxylase (CYP27) gene. These bile alcohols may be intermediates in the alternative cholic acid side chain cleavage pathway. The present study was undertaken to identify enzymes and reactions responsible for the formation of these bile alcohols and to explain why Cyp27(-/-) mice do not show CTX-related abnormalities. Microsomal activities of 5beta-cholestane-3alpha,7alpha,12alpha-triol 25- and 26-hydroxylases, 5beta-cholestane-3alpha,7alpha,12alpha,25-tetrol 23R-, 24S-, and 27-hydroxylases and testosterone 6beta-hydroxylase, a marker enzyme for CYP3A, in Cyp27(-/-) mice livers were markedly up-regulated (5.5-, 3.5-, 6.5-, 7.5-, 2.9-, and 5.4-fold, respectively). In contrast, these enzyme activities were not increased in CTX. The activities of 5beta-cholestane-3alpha,7alpha,12alpha-triol 25- and 26-hydroxylases and 5beta-cholestane-3alpha,7alpha,12alpha,25-tetrol 23R-, 24R-, 24S-, and 27-hydroxylases were strongly correlated with the activities of testosterone 6beta-hydroxylase in control human liver microsomes from eight unrelated donors. Troleandomycin, a specific inhibitor of CYP3A, markedly suppressed these microsomal side chain hydroxylations in both mouse and human livers in a dose-dependent manner. In addition, experiments using recombinant overexpressed human CYP3A4 confirmed that these microsomal side chain hydroxylations were catalyzed by a single enzyme, CYP3A4. The results demonstrate that microsomal 25- and 26-hydroxylations of 5beta-cholestane-3alpha,7alpha,12alpha-triol and microsomal 23R-, 24R-, 24S-, and 27-hydroxylations of 5beta-cholestane-3alpha,7alpha,12alpha,25-tetrol are mainly catalyzed by CYP3A in both mice and humans. Unlike Cyp27(-/-) mice, CYP3A activity was not up-regulated despite marked accumulation of 5beta-cholestane-3alpha,7alpha,12alpha-triol in CTX.
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Affiliation(s)
- A Honda
- Department of Gastroenterology, University of Tsukuba, Tsukuba-city 305-8575, Japan
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42
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Zhang Z, Li D, Blanchard DE, Lear SR, Erickson SK, Spencer TA. Key regulatory oxysterols in liver: analysis as Δ4-3-ketone derivatives by HPLC and response to physiological perturbations. J Lipid Res 2001. [DOI: 10.1016/s0022-2275(20)31174-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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43
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Meaney S, Hassan M, Sakinis A, Lütjohann D, von Bergmann K, Wennmalm Å, Diczfalusy U, Björkhem I. Evidence that the major oxysterols in human circulation originate from distinct pools of cholesterol: a stable isotope study. J Lipid Res 2001. [DOI: 10.1016/s0022-2275(20)32337-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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44
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Sinal CJ, Tohkin M, Miyata M, Ward JM, Lambert G, Gonzalez FJ. Targeted disruption of the nuclear receptor FXR/BAR impairs bile acid and lipid homeostasis. Cell 2000; 102:731-44. [PMID: 11030617 DOI: 10.1016/s0092-8674(00)00062-3] [Citation(s) in RCA: 1336] [Impact Index Per Article: 55.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Mice lacking the nuclear bile acid receptor FXR/BAR developed normally and were outwardly identical to wild-type littermates. FXR/BAR null mice were distinguished from wild-type mice by elevated serum bile acid, cholesterol, and triglycerides, increased hepatic cholesterol and triglycerides, and a proatherogenic serum lipoprotein profile. FXR/BAR null mice also had reduced bile acid pools and reduced fecal bile acid excretion due to decreased expression of the major hepatic canalicular bile acid transport protein. Bile acid repression and induction of cholesterol 7alpha-hydroxylase and the ileal bile acid binding protein, respectively, did not occur in FXR/BAR null mice, establishing the regulatory role of FXR/BAR for the expression of these genes in vivo. These data demonstrate that FXR/BAR is critical for bile acid and lipid homeostasis by virtue of its role as an intracellular bile acid sensor.
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Affiliation(s)
- C J Sinal
- Laboratory of Metabolism, Division of Basic Sciences, National Institutes of Health, Bethesda, Maryland 20892, USA
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45
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Meaney S, Lütjohann D, Diczfalusy U, Björkhem I. Formation of oxysterols from different pools of cholesterol as studied by stable isotope technique: cerebral origin of most circulating 24S-hydroxycholesterol in rats, but not in mice. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1486:293-8. [PMID: 10903480 DOI: 10.1016/s1388-1981(00)00070-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In order to study the origin of different oxysterols in the circulation, in particular 24S-hydroxycholesterol, different pools of cholesterol in rat and mouse were labelled by feeding the animals with a diet supplemented with 0.3 or 0.5% hexadeuterium-labelled cholesterol, respectively, for 10 days. The incorporation of deuterium label in cholesterol and different oxysterols was measured by combined gas chromatography-mass spectrometry in selected tissues and in the circulation. In both rat and mouse, a high incorporation of label was found in cholesterol present in serum and liver (up to 77%). Incorporation of label was similar in 7 alpha- and 7 beta-hydroxycholesterol of the same origin. There was no significant incorporation of deuterium in brain cholesterol, and little or no incorporation in the brain oxysterols investigated, in both animals. In the testis, the incorporation of the deuterium label in cholesterol was less than half of that in the liver, with similarly reduced labelling of the testicular oxysterols. 24S-Hydroxycholesterol in the circulation contained a deuterium content that was about 50% of that of serum and liver cholesterol in the mouse experiment and about 30% in the rat experiment. Thus, about 50% of circulating 24S-hydroxycholesterol in the mouse and about 70% of this fraction in the rat must originate from pools of cholesterol that are not in equilibrium with plasma and liver cholesterol. The liver is probably responsible for a considerable part of the extracerebral formation of 24S-hydroxycholesterol, since this organ contained detectable amounts of 24S-hydroxycholesterol with a relatively high incorporation of deuterium in both animal species. The results are consistent with a cerebral origin of more than half of the 24S-hydroxycholesterol in the circulation of rats, but not in mice.
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Affiliation(s)
- S Meaney
- Division of Clinical Chemistry, Karolinska Institutet at Huddinge University Hospital, Huddinge, Sweden
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46
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Postlind H, Hosseinpour F, Norlin M, Wikvall K. 27-Oxygenation of C27-sterols and 25-hydroxylation of vitamin D3 in kidney: cloning, structure and expression of pig kidney CYP27A. Biochem J 2000; 347:349-56. [PMID: 10749662 PMCID: PMC1220965 DOI: 10.1042/0264-6021:3470349] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This paper describes the molecular cloning of a cytochrome P450 enzyme in pig kidney that catalyses the hydroxylations of vitamin D(3) (cholecalciferol) and C(27)-sterols. DNA sequence analysis of the cDNA revealed that the enzyme belongs to the CYP27 family. The first 36 amino acids have many hallmarks of a mitochondrial signal sequence. The mature pig kidney CYP27 protein contains 498 amino acids. The M(r) of the mature protein was calculated to be 56607. The structure of pig kidney CYP27, as deduced by DNA sequence analysis, shows 77-83% identity with CYP27A in rat, rabbit and human liver. Transfection of the renal CYP27A cDNA into simian COS cells resulted in the synthesis of an enzyme that catalysed the 25-hydroxylation of vitamin D(3) and the 27-hydroxylation of 5beta-cholestane-3alpha,7alpha,12alpha-triol, and the further oxidation of the product into the corresponding C(27)-acid 3alpha,7alpha,12alpha-trihydroxy-5beta-cholestanoic acid. As part of these studies, the enzymic activities of cultured human embryonic kidney cells were examined using vitamin D(3) and C(27)-sterols as substrates. The cells were found to express CYP27A mRNA and to convert the respective substrates into the same products as recombinantly expressed CYP27A, i.e. 25-hydroxyvitamin D(3) and 27-oxygenated C(27)-sterols. The results of the present study describing the structure and expression of CYP27A in kidney suggest that this enzyme is involved in the renal metabolism of vitamin D(3) and that the kidney plays a role in the metabolism of cholesterol and other C(27)-sterols.
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Affiliation(s)
- H Postlind
- Division of Biochemistry, Department of Pharmaceutical Biosciences, University of Uppsala, Box 578, S-751 23 Uppsala, Sweden
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Abstract
Oxygenated derivatives of cholesterol (oxysterols) present a remarkably diverse profile of biological activities, including effects on sphingolipid metabolism, platelet aggregation, apoptosis, and protein prenylation. The most notable oxysterol activities center around the regulation of cholesterol homeostasis, which appears to be controlled in part by a complex series of interactions of oxysterol ligands with various receptors, such as the oxysterol binding protein, the cellular nucleic acid binding protein, the sterol regulatory element binding protein, the LXR nuclear orphan receptors, and the low-density lipoprotein receptor. Identification of the endogenous oxysterol ligands and elucidation of their enzymatic origins are topics of active investigation. Except for 24, 25-epoxysterols, most oxysterols arise from cholesterol by autoxidation or by specific microsomal or mitochondrial oxidations, usually involving cytochrome P-450 species. Oxysterols are variously metabolized to esters, bile acids, steroid hormones, cholesterol, or other sterols through pathways that may differ according to the type of cell and mode of experimentation (in vitro, in vivo, cell culture). Reliable measurements of oxysterol levels and activities are hampered by low physiological concentrations (approximately 0.01-0.1 microM plasma) relative to cholesterol (approximately 5,000 microM) and by the susceptibility of cholesterol to autoxidation, which produces artifactual oxysterols that may also have potent activities. Reports describing the occurrence and levels of oxysterols in plasma, low-density lipoproteins, various tissues, and food products include many unrealistic data resulting from inattention to autoxidation and to limitations of the analytical methodology. Because of the widespread lack of appreciation for the technical difficulties involved in oxysterol research, a rigorous evaluation of the chromatographic and spectroscopic methods used in the isolation, characterization, and quantitation of oxysterols has been included. This review comprises a detailed and critical assessment of current knowledge regarding the formation, occurrence, metabolism, regulatory properties, and other activities of oxysterols in mammalian systems.
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Affiliation(s)
- G J Schroepfer
- Departments of Biochemistry, Rice University, Houston, Texas, USA.
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48
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Wohlfeil ER, Campbell WB. 25-hydroxycholesterol increases eicosanoids and alters morphology in cultured pulmonary artery smooth muscle and endothelial cells. Arterioscler Thromb Vasc Biol 1999; 19:2901-8. [PMID: 10591667 DOI: 10.1161/01.atv.19.12.2901] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
25-hydroxycholesterol (25-OHC) is an oxidized derivative of cholesterol that has been implicated in the early development of arteriosclerosis. Changes in arterial smooth muscle cell (SMC) migration and proliferation have also been linked to the pathophysiology of arteriosclerosis. SMCs undergo "activation" in response to vascular injury by changing phenotypically and by increasing prostaglandin G/H synthase-2 (PGHS-2) protein levels and eicosanoid release. Activation is thought to be important in atheroma formation and arteriosclerosis progression. 25-OHC induces SMCs to change morphologically, increase PGHS-2, and increase eicosanoid release. Confluent monolayers were treated with 25-OHC (10 microg/mL) or the PGHS-2 inducer interleukin-1beta (1 ng/mL) for 18 hours at 37 degrees C. The 18-hour treatment resulted in morphological changes. After uptake of [(14)C]arachidonic acid, released radiolabeled arachidonic acid products were extracted and chromatographed by both normal and reverse-phase high-performance liquid chromatography systems. 25-OHC-treated cells increased their prostaglandin production, with the major component comigrating with a prostaglandin-E(2) standard. HETEs and epoxyeicosatrienoic acids were not affected. Immunoprecipitation analysis of treated and control cell lysates using anti-PGHS-1 and -2 and anti-alpha-actin primary antibodies indicated PGHS-2 induction over control and no change in contractile proteins. These changes are consistent with SMC activation, which occurs in vascular injury models. The notion that oxysterols can activate vascular SMCs may be important in ultimately understanding the pathophysiology of atheroma formation.
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MESH Headings
- Actins/analysis
- Actins/metabolism
- Animals
- Arachidonic Acid/metabolism
- Arachidonic Acid/pharmacology
- Carbon Radioisotopes
- Cells, Cultured
- Chromatography, High Pressure Liquid
- Cyclooxygenase 2
- Endothelium, Vascular/cytology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/enzymology
- Hydroxycholesterols/pharmacology
- Hydroxyeicosatetraenoic Acids/analysis
- Hydroxyeicosatetraenoic Acids/biosynthesis
- Isoenzymes/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Prostaglandin-Endoperoxide Synthases/metabolism
- Prostaglandins/analysis
- Prostaglandins/biosynthesis
- Pulmonary Artery/cytology
- Rabbits
- Subcellular Fractions/chemistry
- Subcellular Fractions/metabolism
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Affiliation(s)
- E R Wohlfeil
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee 53226, USA.
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49
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Furster C, Bergman T, Wikvall K. Biochemical characterization of a truncated form of CYP27A purified from rabbit liver mitochondria. Biochem Biophys Res Commun 1999; 263:663-6. [PMID: 10512735 DOI: 10.1006/bbrc.1999.1426] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
During purification of CYP27A from rabbit liver mitochondria, a cytochrome P450 of different molecular size was co-isolated. The latter enzyme has an apparent M(r) 51,000 which is slightly lower than that of CYP27A. The 51,000-M(r) protein was found to be present in mitochondria from liver, small intestine, kidney, and spleen but not in lung, testis, heart, or brain mitochondria. Determination of the N-terminal sequence revealed that the 51,000-M(r) protein is a truncated form of CYP27A lacking the first 12 residues. The truncated enzyme was less efficient than the full-length CYP27A in the 27-hydroxylation of C(27)-sterols and much less efficient in the 25-hydroxylation of 1alpha-hydroxyvitamin D(3). The K(m) values for cholesterol and 5beta-cholestane-3alpha,7alpha,12alpha-triol were about the same with both enzymes whereas the K(m) for 1alpha-hydroxyvitamin D(3) was much higher with the truncated CYP27A. The results strongly indicate that the 51,000-M(r) protein is formed via proteolytic processing of CYP27A by endogenous protease(s) in some of the tissues examined. The truncation at the N terminus markedly impairs the ability of CYP27A to use 1alpha-hydroxyvitamin D(3) as substrate and to catalyze 25-hydroxylation in the bioactivation of vitamin D(3).
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Affiliation(s)
- C Furster
- Department of Pharmaceutical Biosciences, University of Uppsala, Uppsala, S-751 23, Sweden
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50
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Abstract
This article provides a review of the pathways through which cholesterol is degraded to bile acids. Regulation of key enzymes in the bile acid biosynthestic pathways is discussed. The important role of these pathways in the maintenance of cholesterol homeostasis and the possible therapeutic implications for the treatment of hypercholesterolemia are emphasized.
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Affiliation(s)
- Z R Vlahcevic
- Division of Gastroenterology, Medical College of Virginia, Virginia Commonwealth University, Richmond, USA
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