Metyrapone, an inhibitor of cytochrome oxidases, does not affect viability in a neuroblastoma cell model of bilirubin toxicity
Background: Unconjugated hyperbilirubinemia may cause brain damage in infants, and globally remains a source of neonatal morbidity and mortality. A significant inter-individual variability in vulnerability to bilirubin toxicity remains largely unexplained. An enzyme located in mitochondria oxidizes...
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| Format: | Article |
| Language: | English |
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Elsevier
2014-01-01
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| Series: | Molecular Genetics and Metabolism Reports |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2214426914000305 |
| _version_ | 1818385334973497344 |
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| author | Maria N. Naguib Leerberg Tomas N. Alme Thor W.R. Hansen |
| author_facet | Maria N. Naguib Leerberg Tomas N. Alme Thor W.R. Hansen |
| author_sort | Maria N. Naguib Leerberg |
| collection | DOAJ |
| description | Background: Unconjugated hyperbilirubinemia may cause brain damage in infants, and globally remains a source of neonatal morbidity and mortality. A significant inter-individual variability in vulnerability to bilirubin toxicity remains largely unexplained. An enzyme located in mitochondria oxidizes bilirubin. We hypothesized that inhibiting bilirubin oxidation in human neuronal cell cultures exposed to bilirubin would increase cell death.
Methods: The ability of mitochondrial membranes from CHP-212 human neuroblastoma cells to oxidize bilirubin was verified by spectrophotometry. Intact cells in culture were exposed to bilirubin (75 μM) with or without metyrapone (250 μM) for 24 h, stained with Annexin-V and Propidium iodide and analyzed for apoptosis and necrosis by flow cytometry.
Results: Bilirubin caused a significant reduction of viability, from 84 ± 2.0% (mean ± SEM) vs 67 ± 2.7% (p < 0.05), but adding metyrapone to the bilirubin-exposed cells did not further impact cell viability. Metyrapone alone did not influence cell viability.
Conclusion: Herein we have shown that metyrapone does not increase cell death in neuroblastoma cells in culture exposed to bilirubin. Our results question the relationship between the oxidative mechanism evaluated by spectrophotometry and cell viability. Our findings add to the discussion on whether bilirubin oxidation represents a potentially important protective mechanism in neurons challenged by hyperbilirubinemia. |
| first_indexed | 2024-12-14T03:36:31Z |
| format | Article |
| id | doaj.art-ebc442da1dd84278b8e884c9dc63138e |
| institution | Directory Open Access Journal |
| issn | 2214-4269 |
| language | English |
| last_indexed | 2024-12-14T03:36:31Z |
| publishDate | 2014-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Molecular Genetics and Metabolism Reports |
| spelling | doaj.art-ebc442da1dd84278b8e884c9dc63138e2022-12-21T23:18:36ZengElsevierMolecular Genetics and Metabolism Reports2214-42692014-01-011C19720210.1016/j.ymgmr.2014.04.002Metyrapone, an inhibitor of cytochrome oxidases, does not affect viability in a neuroblastoma cell model of bilirubin toxicityMaria N. Naguib Leerberg0Tomas N. Alme1Thor W.R. Hansen2Department of Pediatric Research, Oslo University Hospital, University of Oslo, NorwayDepartment of Pediatric Research, Oslo University Hospital, University of Oslo, NorwayDepartment of Neonatology, Women & Children's Division, Oslo University Hospital, Rikshospitalet, Oslo, NorwayBackground: Unconjugated hyperbilirubinemia may cause brain damage in infants, and globally remains a source of neonatal morbidity and mortality. A significant inter-individual variability in vulnerability to bilirubin toxicity remains largely unexplained. An enzyme located in mitochondria oxidizes bilirubin. We hypothesized that inhibiting bilirubin oxidation in human neuronal cell cultures exposed to bilirubin would increase cell death. Methods: The ability of mitochondrial membranes from CHP-212 human neuroblastoma cells to oxidize bilirubin was verified by spectrophotometry. Intact cells in culture were exposed to bilirubin (75 μM) with or without metyrapone (250 μM) for 24 h, stained with Annexin-V and Propidium iodide and analyzed for apoptosis and necrosis by flow cytometry. Results: Bilirubin caused a significant reduction of viability, from 84 ± 2.0% (mean ± SEM) vs 67 ± 2.7% (p < 0.05), but adding metyrapone to the bilirubin-exposed cells did not further impact cell viability. Metyrapone alone did not influence cell viability. Conclusion: Herein we have shown that metyrapone does not increase cell death in neuroblastoma cells in culture exposed to bilirubin. Our results question the relationship between the oxidative mechanism evaluated by spectrophotometry and cell viability. Our findings add to the discussion on whether bilirubin oxidation represents a potentially important protective mechanism in neurons challenged by hyperbilirubinemia.http://www.sciencedirect.com/science/article/pii/S2214426914000305BilirubinNeurotoxicityCell cultureKernicterusCytochrome P450 oxidaseMetyrapone |
| spellingShingle | Maria N. Naguib Leerberg Tomas N. Alme Thor W.R. Hansen Metyrapone, an inhibitor of cytochrome oxidases, does not affect viability in a neuroblastoma cell model of bilirubin toxicity Molecular Genetics and Metabolism Reports Bilirubin Neurotoxicity Cell culture Kernicterus Cytochrome P450 oxidase Metyrapone |
| title | Metyrapone, an inhibitor of cytochrome oxidases, does not affect viability in a neuroblastoma cell model of bilirubin toxicity |
| title_full | Metyrapone, an inhibitor of cytochrome oxidases, does not affect viability in a neuroblastoma cell model of bilirubin toxicity |
| title_fullStr | Metyrapone, an inhibitor of cytochrome oxidases, does not affect viability in a neuroblastoma cell model of bilirubin toxicity |
| title_full_unstemmed | Metyrapone, an inhibitor of cytochrome oxidases, does not affect viability in a neuroblastoma cell model of bilirubin toxicity |
| title_short | Metyrapone, an inhibitor of cytochrome oxidases, does not affect viability in a neuroblastoma cell model of bilirubin toxicity |
| title_sort | metyrapone an inhibitor of cytochrome oxidases does not affect viability in a neuroblastoma cell model of bilirubin toxicity |
| topic | Bilirubin Neurotoxicity Cell culture Kernicterus Cytochrome P450 oxidase Metyrapone |
| url | http://www.sciencedirect.com/science/article/pii/S2214426914000305 |
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