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Magny R, Regazzetti A, Kessal K, Christin O, Baudouin C, Roulland E, Brignole-Baudouin F, Laprévote O, Auzeil N. Identification of new Omega-3 very long chain poly-unsaturated fatty acids in meibomian gland secretions. Biochimie 2022; 203:3-10. [PMID: 35476941 DOI: 10.1016/j.biochi.2022.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 03/14/2022] [Accepted: 04/19/2022] [Indexed: 12/16/2022]
Abstract
Three new very long chain polyunsaturated fatty acids (VLC PUFA) belonging to the omega-3 family have been identified in meibum samples collected by Schirmer strips. These VLC PUFA, namely FA (32:3), FA (34:3) and FA (36:3), were detected in O-acyl-ω-hydroxy fatty acids using a molecular network approach, and as free fatty acids. Identification was supported by retention time prediction model, exact mass determination and isotopic patterns. Double bond location was determined using cross metathesis reaction associated to tandem mass spectrometry. In meibum, synthesis of these VLC PUFA is likely to be mediated by elongation of very long chain fatty acids 4 enzyme. The biological role of these newly VLC PUFA and their occurrence in other tissues and biological fluids remains to be elucidated.
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Affiliation(s)
- Romain Magny
- Sorbonne Université UM80, INSERM UMR 968, CNRS UMR 7210, Institut de la Vision, IHU ForeSight, 75012, Paris, France; Université Paris Cité, CNRS, CiTCoM, F-75006, Paris, France.
| | | | - Karima Kessal
- Sorbonne Université UM80, INSERM UMR 968, CNRS UMR 7210, Institut de la Vision, IHU ForeSight, 75012, Paris, France; CIC 1423, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, IHU ForeSight, 75012, Paris, France
| | - Orane Christin
- Université Paris Cité, CNRS, CiTCoM, F-75006, Paris, France
| | - Christophe Baudouin
- Sorbonne Université UM80, INSERM UMR 968, CNRS UMR 7210, Institut de la Vision, IHU ForeSight, 75012, Paris, France; CIC 1423, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, IHU ForeSight, 75012, Paris, France; Hôpital Ambroise Paré, AP-HP, Université Versailles St Quentin en Yvelines, Paris Saclay, 78180, Montigny-Le-Bretonneux, France
| | | | - Françoise Brignole-Baudouin
- Sorbonne Université UM80, INSERM UMR 968, CNRS UMR 7210, Institut de la Vision, IHU ForeSight, 75012, Paris, France; Université Paris Cité, CNRS, CiTCoM, F-75006, Paris, France; Laboratoire d'ophtalmobiologie, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, IHU ForeSight, 75012, Paris, France
| | - Olivier Laprévote
- Université Paris Cité, CNRS, CiTCoM, F-75006, Paris, France; Hôpital Européen Georges Pompidou, AP-HP, Service de Biochimie, 75015, Paris, France
| | - Nicolas Auzeil
- Université Paris Cité, CNRS, CiTCoM, F-75006, Paris, France.
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Zhang L, Borysenko CW, Albright TA, Bittner ER, Lee TR. The cis-trans isomerization of 1,2,5,6-tetrasilacycloocta-3,7-dienes: analysis by mechanistic probes and density functional theory. J Org Chem 2001; 66:5275-83. [PMID: 11485446 DOI: 10.1021/jo0014818] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A series of alkyl- and aryl-substituted derivatives of cis,cis-1,2,5,6-tetrasilacycloocta-3,7-diene were prepared. Isomerization of these compounds to the corresponding trans,trans-1,2,5,6-tetrasilacycloocta-3,7-dienes by exposure to Ru and Zr hydride complexes was explored. Experimental probes of the isomerization were consistent with a stepwise mechanism involving metal hydride addition/elimination rather than one involving radical intermediates. Analysis of the low energy conformers of the various cis and trans isomers of 1,1,2,2,5,5,6,6-octamethyl-1,2,5,6-tetrasilacycloocta-3,7-diene using density functional theory suggested the following trend in stability: trans,trans > cis,trans > cis,cis. The calculated trend in stability was consistent with the experimentally observed unidirectional isomerization of the carbon-carbon double bonds from all cis to all trans and supports a cis,trans isomer as a tenable intermediate.
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Affiliation(s)
- L Zhang
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, USA
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