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de Medina P, Ayadi S, Diallo K, Buñay J, Pucheu L, Soulès R, Record M, Brillouet S, Vija L, Courbon F, Silvente-Poirot S, Poirot M. The Cholesterol-5,6-Epoxide Hydrolase: A Metabolic Checkpoint in Several Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1440:149-161. [PMID: 38036879 DOI: 10.1007/978-3-031-43883-7_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Cholesterol-5,6-epoxides (5,6-ECs) are oxysterols (OS) that have been linked to several pathologies including cancers and neurodegenerative diseases. 5,6-ECs can be produced from cholesterol by several mechanisms including reactive oxygen species, lipoperoxidation, and cytochrome P450 enzymes. 5,6-ECs exist as two different diastereoisomers: 5,6α-EC and 5,6β-EC with different metabolic fates. They can be produced as a mixture or as single products of epoxidation. The epoxide ring of 5,6α-EC and 5,6β-EC is very stable and 5,6-ECs are prone to hydration by the cholesterol-5,6-epoxide hydrolase (ChEH) to give cholestane-3β,5α,6β-triol, which can be further oxidized into oncosterone. 5,6α-EC is prone to chemical and enzymatic conjugation reactions leading to bioactive compounds such as dendrogenins, highlighting the existence of a new metabolic branch on the cholesterol pathway centered on 5,6α-EC. We will summarize in this chapter current knowledge on this pathway which is controlled by the ChEH.
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Affiliation(s)
- Philippe de Medina
- Cancer Research Center of Toulouse (CRCT), Inserm, CNRS, University of Toulouse, Team INOV: "Cholesterol Metabolism and Therapeutic Innovations", Toulouse, France
- Equipe labellisée par la Ligue Nationale contre le Cancer, Toulouse, France
- French Network for Nutrition Physical Activity and Cancer Research (NACRe Network), Jouy-en-Josas, France
| | - Silia Ayadi
- Cancer Research Center of Toulouse (CRCT), Inserm, CNRS, University of Toulouse, Team INOV: "Cholesterol Metabolism and Therapeutic Innovations", Toulouse, France
- Equipe labellisée par la Ligue Nationale contre le Cancer, Toulouse, France
- French Network for Nutrition Physical Activity and Cancer Research (NACRe Network), Jouy-en-Josas, France
| | - Khadijetou Diallo
- Cancer Research Center of Toulouse (CRCT), Inserm, CNRS, University of Toulouse, Team INOV: "Cholesterol Metabolism and Therapeutic Innovations", Toulouse, France
- Equipe labellisée par la Ligue Nationale contre le Cancer, Toulouse, France
- French Network for Nutrition Physical Activity and Cancer Research (NACRe Network), Jouy-en-Josas, France
| | - Julio Buñay
- Cancer Research Center of Toulouse (CRCT), Inserm, CNRS, University of Toulouse, Team INOV: "Cholesterol Metabolism and Therapeutic Innovations", Toulouse, France
- Equipe labellisée par la Ligue Nationale contre le Cancer, Toulouse, France
- French Network for Nutrition Physical Activity and Cancer Research (NACRe Network), Jouy-en-Josas, France
| | - Laly Pucheu
- Cancer Research Center of Toulouse (CRCT), Inserm, CNRS, University of Toulouse, Team INOV: "Cholesterol Metabolism and Therapeutic Innovations", Toulouse, France
- Equipe labellisée par la Ligue Nationale contre le Cancer, Toulouse, France
- French Network for Nutrition Physical Activity and Cancer Research (NACRe Network), Jouy-en-Josas, France
| | - Regis Soulès
- Cancer Research Center of Toulouse (CRCT), Inserm, CNRS, University of Toulouse, Team INOV: "Cholesterol Metabolism and Therapeutic Innovations", Toulouse, France
- Equipe labellisée par la Ligue Nationale contre le Cancer, Toulouse, France
- French Network for Nutrition Physical Activity and Cancer Research (NACRe Network), Jouy-en-Josas, France
| | - Michel Record
- Cancer Research Center of Toulouse (CRCT), Inserm, CNRS, University of Toulouse, Team INOV: "Cholesterol Metabolism and Therapeutic Innovations", Toulouse, France
- Equipe labellisée par la Ligue Nationale contre le Cancer, Toulouse, France
- French Network for Nutrition Physical Activity and Cancer Research (NACRe Network), Jouy-en-Josas, France
| | - Severine Brillouet
- Cancer Research Center of Toulouse (CRCT), Inserm, CNRS, University of Toulouse, Team INOV: "Cholesterol Metabolism and Therapeutic Innovations", Toulouse, France
- Equipe labellisée par la Ligue Nationale contre le Cancer, Toulouse, France
- French Network for Nutrition Physical Activity and Cancer Research (NACRe Network), Jouy-en-Josas, France
- Department of Radiopharmacy, Institut Universitaire du Cancer Toulouse - Oncopole, Toulouse, France
| | - Lavinia Vija
- Cancer Research Center of Toulouse (CRCT), Inserm, CNRS, University of Toulouse, Team INOV: "Cholesterol Metabolism and Therapeutic Innovations", Toulouse, France
- Equipe labellisée par la Ligue Nationale contre le Cancer, Toulouse, France
- French Network for Nutrition Physical Activity and Cancer Research (NACRe Network), Jouy-en-Josas, France
- Department of Medical Imaging, Institut Universitaire du Cancer Toulouse - Oncopole, Toulouse, France
| | - Frederic Courbon
- Cancer Research Center of Toulouse (CRCT), Inserm, CNRS, University of Toulouse, Team INOV: "Cholesterol Metabolism and Therapeutic Innovations", Toulouse, France
- Equipe labellisée par la Ligue Nationale contre le Cancer, Toulouse, France
- French Network for Nutrition Physical Activity and Cancer Research (NACRe Network), Jouy-en-Josas, France
- Department of Medical Imaging, Institut Universitaire du Cancer Toulouse - Oncopole, Toulouse, France
| | - Sandrine Silvente-Poirot
- Cancer Research Center of Toulouse (CRCT), Inserm, CNRS, University of Toulouse, Team INOV: "Cholesterol Metabolism and Therapeutic Innovations", Toulouse, France
- Equipe labellisée par la Ligue Nationale contre le Cancer, Toulouse, France
- French Network for Nutrition Physical Activity and Cancer Research (NACRe Network), Jouy-en-Josas, France
| | - Marc Poirot
- Cancer Research Center of Toulouse (CRCT), Inserm, CNRS, University of Toulouse, Team INOV: "Cholesterol Metabolism and Therapeutic Innovations", Toulouse, France.
- Equipe labellisée par la Ligue Nationale contre le Cancer, Toulouse, France.
- French Network for Nutrition Physical Activity and Cancer Research (NACRe Network), Jouy-en-Josas, France.
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Abstract
Abstract
CX3CR1 is a chemokine receptor with a single ligand, the membrane-tethered chemokine CX3CL1 (fractalkine). All blood monocytes express CX3CR1, but its levels differ between the main 2 subsets, with human CD16+ and murine Gr1low monocytes being CX3CR1hi. Here, we report that absence of either CX3CR1 or CX3CL1 results in a significant reduction of Gr1low blood monocyte levels under both steady-state and inflammatory conditions. Introduction of a Bcl2 transgene restored the wild-type phenotype, suggesting that the CX3C axis provides an essential survival signal. Supporting this notion, we show that CX3CL1 specifically rescues cultured human monocytes from induced cell death. Human CX3CR1 gene polymorphisms are risk factors for atherosclerosis and mice deficient for the CX3C receptor or ligand are relatively protected from atherosclerosis development. However, the mechanistic role of CX3CR1 in atherogenesis remains unclear. Here, we show that enforced survival of monocytes and plaque-resident phagocytes, including foam cells, restored atherogenesis in CX3CR1-deficent mice. The fact that CX3CL1-CX3CR1 interactions confer an essential survival signal, whose absence leads to increased death of monocytes and/or foam cells, might provide a mechanistic explanation for the role of the CX3C chemokine family in atherogenesis.
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Lordan S, Mackrill JJ, O'Brien NM. Involvement of Fas signalling in 7beta-hydroxycholesterol-and cholesterol-5beta,6beta-epoxide-induced apoptosis. Int J Toxicol 2008; 27:279-85. [PMID: 18569169 DOI: 10.1080/10915810802208616] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The induction of apoptosis in cells of the arterial wall is a critical event in the development of atheroma. 7beta-Hydroxycholesterol (7beta-OH) and cholesterol-5beta,6beta-epoxide (beta-epoxide) are components of oxLDL and have previously been shown to be potent inducers of apoptosis. However, the exact mechanisms through which these oxysterols induce apoptosis remains to be fully elucidated. The specific interaction of the Fas death receptor with Fas ligand (FasL) initiates a caspase cascade culminating in apoptosis. The purpose of the present study was to determine the involvement of Fas signalling in 7beta-OH-and beta-epoxide-induced apoptosis. To this end we employed the Fas/FasL antagonist, Kp7-6, and examined the effect of Fas inhibition on oxysterol-induced cell death in U937 cells. Fas levels were increased following 24 h exposure to 30 micro M 7beta-OH while treatment with 30 micro M beta-epoxide had no effect. Kp7-6 reduced the Fas content of 7beta-OH-treated cells to control levels and partially protected against 7beta-OH-induced apoptosis. This coincided with a decrease in cytochrome c release along with a reduction in caspase-3 and caspase-8 activity. Our data implicate Fas signalling in the apoptotic pathway induced by 7beta-OH and also highlight differences between apoptosis induced by 7beta-OH and beta-epoxide.
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Affiliation(s)
- Sinead Lordan
- Department of Food and Nutritional Sciences, University College, Cork, Republic of Ireland
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Abstract
Oxysterols are naturally occurring oxidized derivatives of cholesterol, or by-products of cholesterol biosynthesis, with multiple biologic functions. These compounds display cytotoxic, pro-apoptotic, and pro-inflammatory activities and may play a role in the pathology of atherosclerosis. Their functions as intermediates in the synthesis of bile acids and steroid hormones, and as readily transportable forms of sterol are well established. During the past decade, however, novel physiologic activities of oxysterols have emerged. They are now thought to act as endogenous regulators of gene expression in lipid metabolism. Recently, new intracellular oxysterol receptors have been identified and novel functions of oxysterols in cell signaling discovered, evoking novel interest in these compounds in several branches of biomedical research.
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Affiliation(s)
- Vesa M. Olkkonen
- National Public Health Institute and FIMM, Institute for Molecular Medicine Finland, Biomedicum, Helsinki, Finland
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