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Karadayi R, Pallot C, Cabaret S, Mazzocco J, Gabrielle PH, Semama DS, Chantegret C, Ternoy N, Martin D, Donier A, Gregoire S, Creuzot-Garcher CP, Bron AM, Bretillon L, Berdeaux O, Acar N. Modification of erythrocyte membrane phospholipid composition in preterm newborns with retinopathy of prematurity: The omegaROP study. Front Cell Dev Biol 2022; 10:921691. [PMID: 36158214 PMCID: PMC9504055 DOI: 10.3389/fcell.2022.921691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 07/11/2022] [Indexed: 11/15/2022] Open
Abstract
N-3 polyunsaturated fatty acids (PUFAs) may prevent retinal vascular abnormalities observed in oxygen-induced retinopathy, a model of retinopathy of prematurity (ROP). In the OmegaROP prospective cohort study, we showed that preterm infants who will develop ROP accumulate the n-6 PUFA arachidonic acid (ARA) at the expense of the n-3 PUFA docosahexaenoic acid (DHA) in erythrocytes with advancing gestational age (GA). As mice lacking plasmalogens -That are specific phospholipids considered as reservoirs of n-6 and n-3 PUFAs- Display a ROP-like phenotype, the aim of this study was to determine whether plasmalogens are responsible for the changes observed in subjects from the OmegaROP study. Accordingly, preterm infants aged less than 29 weeks GA were recruited at birth in the Neonatal Intensive Care Unit of University Hospital Dijon, France. Blood was sampled very early after birth to avoid any nutritional influence on its lipid composition. The lipid composition of erythrocytes and the structure of phospholipids including plasmalogens were determined by global lipidomics using liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS). LC-HRMS data confirmed our previous observations by showing a negative association between the erythrocyte content in phospholipid esterified to n-6 PUFAs and GA in infants without ROP (rho = -0.485, p = 0.013 and rho = -0.477, p = 0.015 for ethanolamine and choline total phospholipids, respectively). Phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdEtn) species with ARA, namely PtdCho16:0/20:4 (rho = -0.511, p < 0.01) and PtdEtn18:1/20:4 (rho = -0.479, p = 0.015), were the major contributors to the relationship observed. On the contrary, preterm infants developing ROP displayed negative association between PtdEtn species with n-3 PUFAs and GA (rho = -0.380, p = 0.034). They were also characterized by a positive association between GA and the ratio of ethanolamine plasmalogens (PlsEtn) with n-6 PUFA to PlsEtn with n-3 PUFAs (rho = 0.420, p = 0.029), as well as the ratio of PlsEtn with ARA to PlsEtn with DHA (rho = 0.843, p = 0.011). Altogether, these data confirm the potential accumulation of n-6 PUFAs with advancing GA in erythrocytes of infants developing ROP. These changes may be partly due to plasmalogens.
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Affiliation(s)
- Rémi Karadayi
- Centre des Sciences du Goût et de l’Alimentation, Institut Agro, CNRS, INRAE, Université Bourgogne Franche-Comté, Eye and Nutrition Research Group, Dijon, France
| | - Charlotte Pallot
- Centre des Sciences du Goût et de l’Alimentation, Institut Agro, CNRS, INRAE, Université Bourgogne Franche-Comté, Eye and Nutrition Research Group, Dijon, France
- University Hospital, Department of Ophthalmology, Dijon, France
| | - Stéphanie Cabaret
- Centre des Sciences du Goût et de l’Alimentation, Institut Agro, CNRS, INRAE, Université Bourgogne Franche-Comté, ChemoSens Platform, Dijon, France
| | - Julie Mazzocco
- Centre des Sciences du Goût et de l’Alimentation, Institut Agro, CNRS, INRAE, Université Bourgogne Franche-Comté, Eye and Nutrition Research Group, Dijon, France
| | | | - Denis S. Semama
- University Hospital, Neonatal Intensive Care Unit, Dijon, France
| | | | - Ninon Ternoy
- University Hospital, Neonatal Intensive Care Unit, Dijon, France
| | - Delphine Martin
- University Hospital, Neonatal Intensive Care Unit, Dijon, France
| | - Aurélie Donier
- University Hospital, Neonatal Intensive Care Unit, Dijon, France
| | - Stéphane Gregoire
- Centre des Sciences du Goût et de l’Alimentation, Institut Agro, CNRS, INRAE, Université Bourgogne Franche-Comté, Eye and Nutrition Research Group, Dijon, France
| | - Catherine P. Creuzot-Garcher
- Centre des Sciences du Goût et de l’Alimentation, Institut Agro, CNRS, INRAE, Université Bourgogne Franche-Comté, Eye and Nutrition Research Group, Dijon, France
- University Hospital, Department of Ophthalmology, Dijon, France
| | - Alain M. Bron
- Centre des Sciences du Goût et de l’Alimentation, Institut Agro, CNRS, INRAE, Université Bourgogne Franche-Comté, Eye and Nutrition Research Group, Dijon, France
- University Hospital, Department of Ophthalmology, Dijon, France
| | - Lionel Bretillon
- Centre des Sciences du Goût et de l’Alimentation, Institut Agro, CNRS, INRAE, Université Bourgogne Franche-Comté, Eye and Nutrition Research Group, Dijon, France
| | - Olivier Berdeaux
- Centre des Sciences du Goût et de l’Alimentation, Institut Agro, CNRS, INRAE, Université Bourgogne Franche-Comté, ChemoSens Platform, Dijon, France
| | - Niyazi Acar
- Centre des Sciences du Goût et de l’Alimentation, Institut Agro, CNRS, INRAE, Université Bourgogne Franche-Comté, Eye and Nutrition Research Group, Dijon, France
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Liu H, Zuo F, Wu H. Blockage of cytosolic phospholipase A2 alpha by monoclonal antibody attenuates focal ischemic brain damage in mice. Biosci Trends 2017; 11:439-449. [DOI: 10.5582/bst.2017.01046] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Hui Liu
- Department of Neurology, The Brain Branch of Heibei Province Cangzhou Central Hospital
| | - Fengtong Zuo
- Department of Neurology, The Brain Branch of Heibei Province Cangzhou Central Hospital
| | - Huijun Wu
- Department of Neurology, The Brain Branch of Heibei Province Cangzhou Central Hospital
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Bromoenol Lactone Attenuates Nicotine-Induced Breast Cancer Cell Proliferation and Migration. PLoS One 2015; 10:e0143277. [PMID: 26588686 PMCID: PMC4654479 DOI: 10.1371/journal.pone.0143277] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Accepted: 11/03/2015] [Indexed: 12/18/2022] Open
Abstract
Objectives Calcium independent group VIA phospholipase A2 (iPLA2β) and Matrix Metalloproteinase-9 (MMP-9) are upregulated in many disease states; their involvement with cancer cell migration has been a recent subject for study. Further, the molecular mechanisms mediating nicotine-induced breast cancer cell progression have not been fully investigated. This study aims to investigate whether iPLA2β mediates nicotine-induced breast cancer cell proliferation and migration through both in-vitro and in-vivo techniques. Subsequently, the ability of Bromoenol Lactone (BEL) to attenuate the severity of nicotine-induced breast cancer was examined. Method and Results We found that BEL significantly attenuated both basal and nicotine-induced 4T1 breast cancer cell proliferation, via an MTT proliferation assay. Breast cancer cell migration was examined by both a scratch and transwell assay, in which, BEL was found to significantly decrease both basal and nicotine-induced migration. Additionally, nicotine-induced MMP-9 expression was found to be mediated in an iPLA2β dependent manner. These results suggest that iPLA2β plays a critical role in mediating both basal and nicotine-induced breast cancer cell proliferation and migration in-vitro. In an in-vivo mouse breast cancer model, BEL treatment was found to significantly reduce both basal (p<0.05) and nicotine-induced tumor growth (p<0.01). Immunohistochemical analysis showed BEL decreased nicotine-induced MMP-9, HIF-1alpha, and CD31 tumor tissue expression. Subsequently, BEL was observed to reduce nicotine-induced lung metastasis. Conclusion The present study indicates that nicotine-induced migration is mediated by MMP-9 production in an iPLA2β dependent manner. Our data suggests that BEL is a possible chemotherapeutic agent as it was found to reduce both nicotine-induced breast cancer tumor growth and lung metastasis.
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McArthur S, Gobbetti T, Kusters DHM, Reutelingsperger CP, Flower RJ, Perretti M. Definition of a Novel Pathway Centered on Lysophosphatidic Acid To Recruit Monocytes during the Resolution Phase of Tissue Inflammation. THE JOURNAL OF IMMUNOLOGY 2015; 195:1139-51. [PMID: 26101324 PMCID: PMC4505961 DOI: 10.4049/jimmunol.1500733] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 05/21/2015] [Indexed: 01/13/2023]
Abstract
Blood-derived monocytes remove apoptotic cells and terminate inflammation in settings as diverse as atherosclerosis and Alzheimer’s disease. They express high levels of the proresolving receptor ALX/FPR2, which is activated by the protein annexin A1 (ANXA1), found in high abundance in inflammatory exudates. Using primary human blood monocytes from healthy donors, we identified ANXA1 as a potent CD14+CD16− monocyte chemoattractant, acting via ALX/FPR2. Downstream signaling pathway analysis revealed the p38 MAPK-mediated activation of a calcium independent phospholipase A2 with resultant synthesis of lysophosphatidic acid (LPA) driving chemotaxis through LPA receptor 2 and actin cytoskeletal mobilization. In vivo experiments confirmed ANXA1 as an independent phospholipase A2–dependent monocyte recruiter; congruently, monocyte recruitment was significantly impaired during ongoing zymosan-induced inflammation in AnxA1−/− or alx/fpr2/3−/− mice. Using a dorsal air-pouch model, passive transfer of apoptotic neutrophils between AnxA1−/− and wild-type mice identified effete neutrophils as the primary source of soluble ANXA1 in inflammatory resolution. Together, these data elucidate a novel proresolving network centered on ANXA1 and LPA generation and identify previously unappreciated determinants of ANXA1 and ALX/FPR2 signaling in monocytes.
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Affiliation(s)
- Simon McArthur
- William Harvey Research Institute, Barts and London School of Medicine, Queen Mary University of London, London, EC1M 6BQ, United Kingdom;
| | - Thomas Gobbetti
- William Harvey Research Institute, Barts and London School of Medicine, Queen Mary University of London, London, EC1M 6BQ, United Kingdom
| | - Dennis H M Kusters
- CARIM School for Cardiovascular Diseases, Maastricht University, 6200 MD Maastricht, the Netherlands; and Department of Biochemistry, Maastricht University, 6200 MD Maastricht, the Netherlands
| | - Christopher P Reutelingsperger
- CARIM School for Cardiovascular Diseases, Maastricht University, 6200 MD Maastricht, the Netherlands; and Department of Biochemistry, Maastricht University, 6200 MD Maastricht, the Netherlands
| | - Roderick J Flower
- William Harvey Research Institute, Barts and London School of Medicine, Queen Mary University of London, London, EC1M 6BQ, United Kingdom
| | - Mauro Perretti
- William Harvey Research Institute, Barts and London School of Medicine, Queen Mary University of London, London, EC1M 6BQ, United Kingdom;
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Saab S, Mazzocco J, Creuzot-Garcher CP, Bron AM, Bretillon L, Acar N. Plasmalogens in the retina: From occurrence in retinal cell membranes to potential involvement in pathophysiology of retinal diseases. Biochimie 2014; 107 Pt A:58-65. [DOI: 10.1016/j.biochi.2014.07.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 07/26/2014] [Indexed: 10/24/2022]
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Saab S, Buteau B, Leclère L, Bron AM, Creuzot-Garcher CP, Bretillon L, Acar N. Involvement of plasmalogens in post-natal retinal vascular development. PLoS One 2014; 9:e101076. [PMID: 24963632 PMCID: PMC4071069 DOI: 10.1371/journal.pone.0101076] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 06/03/2014] [Indexed: 01/05/2023] Open
Abstract
Objective Proper development of retinal blood vessels is essential to ensure sufficient oxygen and nutrient supplies to the retina. It was shown that polyunsaturated fatty acids (PUFAs) could modulate factors involved in tissue vascularization. A congenital deficiency in ether-phospholipids, also termed “plasmalogens”, was shown to lead to abnormal ocular vascularization. Because plasmalogens are considered to be reservoirs of PUFAs, we wished to improve our understanding of the mechanisms by which plasmalogens regulate retinal vascular development and whether the release of PUFAs by calcium-independent phospholipase A2 (iPLA2) could be involved. Methods and Results By characterizing the cellular and molecular steps of retinal vascular development in a mouse model of plasmalogen deficiency, we demonstrated that plasmalogens modulate angiogenic processes during the early phases of retinal vascularization. They influence glial activity and primary astrocyte template formation, endothelial cell proliferation and retinal vessel outgrowth, and impact the expression of the genes involved in angiogenesis in the retina. These early defects led to a disorganized and dysfunctional retinal vascular network at adult age. By comparing these data to those obtained on a mouse model of retinal iPLA2 inhibition, we suggest that these processes may be mediated by PUFAs released from plasmalogens and further signalling through the angiopoietin/tie pathways. Conclusions These data suggest that plasmalogens play a crucial role in retinal vascularization processes.
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Affiliation(s)
- Sarah Saab
- CNRS, UMR6265 Centre des Sciences du Goût et de l’Alimentation, Dijon, France
- INRA, UMR1324 Centre des Sciences du Goût et de l’Alimentation, Dijon, France
- Université de Bourgogne, UMR Centre des Sciences du Goût et de l’Alimentation, Dijon, France
| | - Bénédicte Buteau
- CNRS, UMR6265 Centre des Sciences du Goût et de l’Alimentation, Dijon, France
- INRA, UMR1324 Centre des Sciences du Goût et de l’Alimentation, Dijon, France
- Université de Bourgogne, UMR Centre des Sciences du Goût et de l’Alimentation, Dijon, France
| | - Laurent Leclère
- CNRS, UMR6265 Centre des Sciences du Goût et de l’Alimentation, Dijon, France
- INRA, UMR1324 Centre des Sciences du Goût et de l’Alimentation, Dijon, France
- Université de Bourgogne, UMR Centre des Sciences du Goût et de l’Alimentation, Dijon, France
| | - Alain M. Bron
- CNRS, UMR6265 Centre des Sciences du Goût et de l’Alimentation, Dijon, France
- INRA, UMR1324 Centre des Sciences du Goût et de l’Alimentation, Dijon, France
- Université de Bourgogne, UMR Centre des Sciences du Goût et de l’Alimentation, Dijon, France
- Department of Ophthalmology, University Hospital, Dijon, France
| | - Catherine P. Creuzot-Garcher
- CNRS, UMR6265 Centre des Sciences du Goût et de l’Alimentation, Dijon, France
- INRA, UMR1324 Centre des Sciences du Goût et de l’Alimentation, Dijon, France
- Université de Bourgogne, UMR Centre des Sciences du Goût et de l’Alimentation, Dijon, France
- Department of Ophthalmology, University Hospital, Dijon, France
| | - Lionel Bretillon
- CNRS, UMR6265 Centre des Sciences du Goût et de l’Alimentation, Dijon, France
- INRA, UMR1324 Centre des Sciences du Goût et de l’Alimentation, Dijon, France
- Université de Bourgogne, UMR Centre des Sciences du Goût et de l’Alimentation, Dijon, France
| | - Niyazi Acar
- CNRS, UMR6265 Centre des Sciences du Goût et de l’Alimentation, Dijon, France
- INRA, UMR1324 Centre des Sciences du Goût et de l’Alimentation, Dijon, France
- Université de Bourgogne, UMR Centre des Sciences du Goût et de l’Alimentation, Dijon, France
- * E-mail:
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7
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Tyurina YY, Poloyac SM, Tyurin VA, Kapralov AA, Jiang J, Anthonymuthu TS, Kapralova VI, Vikulina AS, Jung MY, Epperly MW, Mohammadyani D, Klein-Seetharaman J, Jackson TC, Kochanek PM, Pitt BR, Greenberger JS, Vladimirov YA, Bayır H, Kagan VE. A mitochondrial pathway for biosynthesis of lipid mediators. Nat Chem 2014; 6:542-52. [PMID: 24848241 PMCID: PMC4201180 DOI: 10.1038/nchem.1924] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 03/16/2014] [Indexed: 01/20/2023]
Abstract
The central role of mitochondria in metabolic pathways and in cell-death mechanisms requires sophisticated signalling systems. Essential in this signalling process is an array of lipid mediators derived from polyunsaturated fatty acids. However, the molecular machinery for the production of oxygenated polyunsaturated fatty acids is localized in the cytosol and their biosynthesis has not been identified in mitochondria. Here we report that a range of diversified polyunsaturated molecular species derived from a mitochondria-specific phospholipid, cardiolipin (CL), is oxidized by the intermembrane-space haemoprotein, cytochrome c. We show that a number of oxygenated CL species undergo phospholipase A2-catalysed hydrolysis and thus generate multiple oxygenated fatty acids, including well-known lipid mediators. This represents a new biosynthetic pathway for lipid mediators. We demonstrate that this pathway, which includes the oxidation of polyunsaturated CLs and accumulation of their hydrolysis products (oxygenated linoleic, arachidonic acids and monolysocardiolipins), is activated in vivo after acute tissue injury.
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Affiliation(s)
- Yulia Y. Tyurina
- Center for Free Radical and Antioxidant Health, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
| | - Samuel M. Poloyac
- Department of Pharmaceutical Sciences, School of Pharmacy, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
| | - Vladimir A. Tyurin
- Center for Free Radical and Antioxidant Health, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
- Department of Environmental Health, Graduate School of Public Health, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
| | - Alexander A. Kapralov
- Center for Free Radical and Antioxidant Health, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
- Department of Environmental Health, Graduate School of Public Health, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
| | - Jianfei Jiang
- Center for Free Radical and Antioxidant Health, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
- Department of Environmental Health, Graduate School of Public Health, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
| | - Tamil Selvan Anthonymuthu
- Center for Free Radical and Antioxidant Health, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
- Department of Critical Care Medicine, Safar Center for Resuscitation Research, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
| | - Valentina I. Kapralova
- Center for Free Radical and Antioxidant Health, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
- Department of Environmental Health, Graduate School of Public Health, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
| | - Anna S. Vikulina
- Center for Free Radical and Antioxidant Health, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
- Department of Environmental Health, Graduate School of Public Health, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
- Department of Biophysics, MV Lomonosov Moscow State University, Moscow, Russia
| | - Mi-Yeon Jung
- Center for Free Radical and Antioxidant Health, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
- Department of Environmental Health, Graduate School of Public Health, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
| | - Michael W. Epperly
- Department of Radiation Oncology, School of Medicine, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
| | - Dariush Mohammadyani
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
| | | | - Travis C. Jackson
- Department of Critical Care Medicine, Safar Center for Resuscitation Research, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
| | - Patrick M. Kochanek
- Department of Critical Care Medicine, Safar Center for Resuscitation Research, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
| | - Bruce R. Pitt
- Department of Environmental Health, Graduate School of Public Health, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
| | - Joel S. Greenberger
- Department of Radiation Oncology, School of Medicine, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
| | - Yury A. Vladimirov
- Department of Biophysics, MV Lomonosov Moscow State University, Moscow, Russia
| | - Hülya Bayır
- Center for Free Radical and Antioxidant Health, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
- Department of Critical Care Medicine, Safar Center for Resuscitation Research, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
| | - Valerian E. Kagan
- Center for Free Radical and Antioxidant Health, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
- Department of Environmental Health, Graduate School of Public Health, Swanson School of Engineering, University of Pittsburgh, Pittsburgh PA 15213, USA
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Lupo G, Motta C, Giurdanella G, Anfuso CD, Alberghina M, Drago F, Salomone S, Bucolo C. Role of phospholipases A2 in diabetic retinopathy: in vitro and in vivo studies. Biochem Pharmacol 2013; 86:1603-13. [PMID: 24076420 DOI: 10.1016/j.bcp.2013.09.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 09/09/2013] [Accepted: 09/09/2013] [Indexed: 12/13/2022]
Abstract
Diabetic retinopathy is one of the leading causes of blindness and the most common complication of diabetes with no cure available. We investigated the role of phospholipases A2 (PLA2) in diabetic retinopathy using an in vitro blood-retinal barrier model (BRB) and an in vivo streptozotocin (STZ)-induced diabetic model. Mono- and co-cultures of endothelial cells (EC) and pericytes (PC), treated with high or fluctuating concentrations of glucose, to mimic the diabetic condition, were used. PLA2 activity, VEGF and PGE2 levels and cell proliferation were measured, with or without PLA2 inhibition. Diabetes was induced in rats by STZ injection and PLA2 activity along with VEGF, TNFα and ICAM-1 levels were measured in retina. High or fluctuating glucose induced BRB breakdown, and increased PLA2 activity, PGE2 and VEGF in EC/PC co-cultures; inhibition of PLA2 in mono- or co-cultures treated with high or fluctuating glucose dampened PGE2 and VEGF production down to the levels of controls. High or fluctuating glucose increased EC number and reduced PC number in co-cultures; these effects were reversed after transfecting EC with small interfering RNA targeted to PLA2. PLA2 and COX-2 protein expressions were significantly increased in microvessels from retina of diabetic rats. Diabetic rats had also high retinal levels of VEGF, ICAM-1 and TNFα that were reduced by treatment with a cPLA2 inhibitor. In conclusion, the present findings indicate that PLA2 upregulation represents an early step in glucose-induced alteration of BRB, possibly upstream of VEGF; thus, PLA2 may be an interesting target in managing diabetic retinopathy.
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Affiliation(s)
- Gabriella Lupo
- Department of Clinical and Molecular Biomedicine, Section of Pharmacology and Biochemistry, School of Medicine, University of Catania, Catania, Italy
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Jenkins CM, Yang J, Gross RW. Mechanism-based inhibition of iPLA2β demonstrates a highly reactive cysteine residue (C651) that interacts with the active site: mass spectrometric elucidation of the mechanisms underlying inhibition. Biochemistry 2013; 52:4250-63. [PMID: 23701211 DOI: 10.1021/bi4004233] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The multifaceted roles of calcium-independent phospholipase A2β (iPLA2β) in numerous cellular processes have been extensively examined through utilization of the iPLA2-selective inhibitor (E)-6-(bromomethylene)-3-(1-naphthalenyl)-2H-tetrahydropyran-2-one (BEL). Herein, we employed accurate mass/high resolution mass spectrometry to demonstrate that the active site serine (S465) and C651 of iPLA2β are covalently cross-linked during incubations with BEL demonstrating their close spatial proximity. This cross-link results in macroscopic alterations in enzyme molecular geometry evidenced by anomalous migration of the cross-linked enzyme by SDS-PAGE. Molecular models of iPLA2β constructed from the crystal structure of iPLA2α (patatin) indicate that the distance between S465 and C651 is approximately 10 Å within the active site of iPLA2β. Kinetic analysis of the formation of the 75 kDa iPLA2β-BEL species with the (R) and (S) enantiomers of BEL demonstrated that the reaction of (S)-BEL with iPLA2β was more rapid than for (R)-BEL paralleling the enantioselectivity for the inhibition of catalysis by each inhibitor with iPLA2β. Moreover, we demonstrate that the previously identified selective acylation of iPLA2β by oleoyl-CoA occurs at C651 thereby indicating the importance of active site architecture for acylation of this enzyme. Collectively, these results identify C651 as a highly reactive nucleophilic residue within the active site of iPLA2β which is thioesterified by BEL, acylated by oleoyl-CoA, and located in close spatial proximity to the catalytic serine thereby providing important chemical insights on the mechanisms through which BEL inhibits iPLA2β and the topology of the active site.
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Affiliation(s)
- Christopher M Jenkins
- Division of Bioorganic Chemistry and Molecular Pharmacology, Washington University School of Medicine , St. Louis, Missouri 63110, USA
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