1
|
Davidsen N, Lauvås AJ, Myhre O, Ropstad E, Carpi D, Gyves EMD, Berntsen HF, Dirven H, Paulsen RE, Bal-Price A, Pistollato F. Exposure to human relevant mixtures of halogenated persistent organic pollutants (POPs) alters neurodevelopmental processes in human neural stem cells undergoing differentiation. Reprod Toxicol 2021; 100:17-34. [PMID: 33333158 PMCID: PMC7992035 DOI: 10.1016/j.reprotox.2020.12.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 12/03/2020] [Accepted: 12/11/2020] [Indexed: 12/11/2022]
Abstract
Halogenated persistent organic pollutants (POPs) like perfluorinated alkylated substances (PFASs), brominated flame retardants (BFRs), organochlorine pesticides and polychlorinated biphenyls (PCBs) are known to cause cancer, immunotoxicity, neurotoxicity and interfere with reproduction and development. Concerns have been raised about the impact of POPs upon brain development and possibly neurodevelopmental disorders. The developing brain is a particularly vulnerable organ due to dynamic and complex neurodevelopmental processes occurring early in life. However, very few studies have reported on the effects of POP mixtures at human relevant exposures, and their impact on key neurodevelopmental processes using human in vitro test systems. Aiming to reduce this knowledge gap, we exposed mixed neuronal/glial cultures differentiated from neural stem cells (NSCs) derived from human induced pluripotent stem cells (hiPSCs) to reconstructed mixtures of 29 different POPs using concentrations comparable to Scandinavian human blood levels. Effects of the POP mixtures on neuronal proliferation, differentiation and synaptogenesis were evaluated using in vitro assays anchored to common key events identified in the existing developmental neurotoxicity (DNT) adverse outcome pathways (AOPs). The present study showed that mixtures of POPs (in particular brominated and chlorinated compounds) at human relevant concentrations increased proliferation of NSCs and decreased synapse number. Based on a mathematical modelling, synaptogenesis and neurite outgrowth seem to be the most sensitive DNT in vitro endpoints. Our results indicate that prenatal exposure to POPs may affect human brain development, potentially contributing to recently observed learning and memory deficits in children.
Collapse
Affiliation(s)
- Nichlas Davidsen
- Department of Environmental Health, Section for Toxicology and Risk Assessment, Norwegian Institute of Public Health, Oslo, Norway
| | - Anna Jacobsen Lauvås
- Department of Environmental Health, Section for Toxicology and Risk Assessment, Norwegian Institute of Public Health, Oslo, Norway
| | - Oddvar Myhre
- Department of Environmental Health, Section for Toxicology and Risk Assessment, Norwegian Institute of Public Health, Oslo, Norway
| | - Erik Ropstad
- Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Donatella Carpi
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | | | - Hanne Friis Berntsen
- Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway; National Institute of Occupational Health, Oslo, Norway
| | - Hubert Dirven
- Department of Environmental Health, Section for Toxicology and Risk Assessment, Norwegian Institute of Public Health, Oslo, Norway
| | - Ragnhild E Paulsen
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Norway
| | - Anna Bal-Price
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | | |
Collapse
|
2
|
Lindeman B, Johansson Y, Andreassen M, Husøy T, Dirven H, Hofer T, Knutsen HK, Caspersen IH, Vejrup K, Paulsen RE, Alexander J, Forsby A, Myhre O. Does the food processing contaminant acrylamide cause developmental neurotoxicity? A review and identification of knowledge gaps. Reprod Toxicol 2021; 101:93-114. [PMID: 33617935 DOI: 10.1016/j.reprotox.2021.02.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 01/11/2021] [Accepted: 02/16/2021] [Indexed: 12/15/2022]
Abstract
There is a worldwide concern on adverse health effects of dietary exposure to acrylamide (AA) due to its presence in commonly consumed foods. AA is formed when carbohydrate rich foods containing asparagine and reducing sugars are prepared at high temperatures and low moisture conditions. Upon oral intake, AA is rapidly absorbed and distributed to all organs. AA is a known human neurotoxicant that can reach the developing foetus via placental transfer and breast milk. Although adverse neurodevelopmental effects have been observed after prenatal AA exposure in rodents, adverse effects of AA on the developing brain has so far not been studied in humans. However, epidemiological studies indicate that gestational exposure to AA impair foetal growth and AA exposure has been associated with reduced head circumference of the neonate. Thus, there is an urgent need for further research to elucidate whether pre- and perinatal AA exposure in humans might impair neurodevelopment and adversely affect neuronal function postnatally. Here, we review the literature with emphasis on the identification of critical knowledge gaps in relation to neurodevelopmental toxicity of AA and its mode of action and we suggest research strategies to close these gaps to better protect the unborn child.
Collapse
Affiliation(s)
- Birgitte Lindeman
- Department of Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Ylva Johansson
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Mathilda Andreassen
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Trine Husøy
- Department of Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Hubert Dirven
- Department of Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Tim Hofer
- Department of Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Helle K Knutsen
- Department of Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Ida H Caspersen
- Centre for Fertility and Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Kristine Vejrup
- Department of Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Ragnhild E Paulsen
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Norway
| | - Jan Alexander
- Department of Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Anna Forsby
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Oddvar Myhre
- Department of Environmental Health, Norwegian Institute of Public Health, Oslo, Norway.
| |
Collapse
|
3
|
Affiliation(s)
- Sigvart Evjen
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
| | | | - Mona Gaarder
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, 0316 Oslo, Norway
| | - Ragnhild E. Paulsen
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, 0316 Oslo, Norway
| | - Anne Fiksdahl
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
| | - Hanna K. Knuutila
- Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), 7034 Trondheim, Norway
| |
Collapse
|
4
|
Fjelldal MF, Freyd T, Evenseth LM, Sylte I, Ring A, Paulsen RE. Exploring the overlapping binding sites of ifenprodil and EVT-101 in GluN2B-containing NMDA receptors using novel chicken embryo forebrain cultures and molecular modeling. Pharmacol Res Perspect 2019; 7:e00480. [PMID: 31164987 PMCID: PMC6543015 DOI: 10.1002/prp2.480] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 04/15/2019] [Accepted: 04/15/2019] [Indexed: 12/22/2022] Open
Abstract
N-methyl-d-aspartate receptors (NMDAR) are widely expressed in the brain. GluN2B subunit-containing NMDARs has recently attracted significant attention as potential pharmacological targets, with emphasis on the functional properties of allosteric antagonists. We used primary cultures from chicken embryo forebrain (E10), expressing native GluN2B-containing NMDA receptors as a novel model system. Comparing the inhibition of calcium influx by well-known GluN2B subunit-specific allosteric antagonists, the following rank order of potency was found: EVT-101 (EC 50 22 ± 8 nmol/L) > Ro 25-6981 (EC 50 60 ± 30 nmol/L) > ifenprodil (EC 50 100 ± 40 nmol/L) > eliprodil (EC 50 1300 ± 700 nmol/L), similar to previous observations in rat cortical cultures and cell lines overexpressing chimeric receptors. The less explored Ro 04-5595 had an EC 50 of 186 ± 32 nmol/L. Venturing to explain the differences in potency, binding properties were further studied by in silico docking and molecular dynamics simulations using x-ray crystal structures of GluN1/GluN2B amino terminal domain. We found that Ro 04-5595 was predicted to bind the recently discovered EVT-101 binding site, not the ifenprodil-binding site. The EVT-101 binding pocket appears to accommodate more structurally different ligands than the ifenprodil-binding site, and contains residues essential in ligand interactions necessary for calcium influx inhibition. For the ifenprodil site, the less effective antagonist (eliprodil) fails to interact with key residues, while in the EVT-101 pocket, difference in potency might be explained by differences in ligand-receptor interaction patterns.
Collapse
Affiliation(s)
- Marthe F. Fjelldal
- Department of Pharmaceutical BiosciencesSchool of PharmacyUniversity of OsloOsloNorway
- Norwegian Defence Research EstablishmentKjellerNorway
- Realomics Strategic Research InitiativeOsloNorway
| | - Thibaud Freyd
- Molecular Pharmacology and ToxicologyDepartment of Medical BiologyUniversity of Tromsø—The Arctic University of NorwayTromsøNorway
- Department of ChemistryHylleraas Centre for Quantum Molecular SciencesUniversity of OsloOsloNorway
| | - Linn M. Evenseth
- Molecular Pharmacology and ToxicologyDepartment of Medical BiologyUniversity of Tromsø—The Arctic University of NorwayTromsøNorway
| | - Ingebrigt Sylte
- Molecular Pharmacology and ToxicologyDepartment of Medical BiologyUniversity of Tromsø—The Arctic University of NorwayTromsøNorway
| | - Avi Ring
- Norwegian Defence Research EstablishmentKjellerNorway
| | - Ragnhild E. Paulsen
- Department of Pharmaceutical BiosciencesSchool of PharmacyUniversity of OsloOsloNorway
- Realomics Strategic Research InitiativeOsloNorway
| |
Collapse
|
5
|
Stahl K, Rahmani S, Prydz A, Skauli N, MacAulay N, Mylonakou MN, Torp R, Skare Ø, Berg T, Leergaard TB, Paulsen RE, Ottersen OP, Amiry-Moghaddam M. Targeted deletion of the aquaglyceroporin AQP9 is protective in a mouse model of Parkinson's disease. PLoS One 2018; 13:e0194896. [PMID: 29566083 PMCID: PMC5864064 DOI: 10.1371/journal.pone.0194896] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Accepted: 03/12/2018] [Indexed: 12/21/2022] Open
Abstract
More than 90% of the cases of Parkinson’s disease have unknown etiology. Gradual loss of dopaminergic neurons of substantia nigra is the main cause of morbidity in this disease. External factors such as environmental toxins are believed to play a role in the cell loss, although the cause of the selective vulnerability of dopaminergic neurons remains unknown. We have previously shown that aquaglyceroporin AQP9 is expressed in dopaminergic neurons and astrocytes of rodent brain. AQP9 is permeable to a broad spectrum of substrates including purines, pyrimidines, and lactate, in addition to water and glycerol. Here we test our hypothesis that AQP9 serves as an influx route for exogenous toxins and, hence, may contribute to the selective vulnerability of nigral dopaminergic (tyrosine hydroxylase-positive) neurons. Using Xenopus oocytes injected with Aqp9 cRNA, we show that AQP9 is permeable to the parkinsonogenic toxin 1-methyl-4-phenylpyridinium (MPP+). Stable expression of AQP9 in HEK cells increases their vulnerability to MPP+ and to arsenite—another parkinsonogenic toxin. Conversely, targeted deletion of Aqp9 in mice protects nigral dopaminergic neurons against MPP+ toxicity. A protective effect of Aqp9 deletion was demonstrated in organotypic slice cultures of mouse midbrain exposed to MPP+in vitro and in mice subjected to intrastriatal injections of MPP+in vivo. Seven days after intrastriatal MPP+ injections, the population of tyrosine hydroxylase-positive cells in substantia nigra is reduced by 48% in Aqp9 knockout mice compared with 67% in WT littermates. Our results show that AQP9 –selectively expressed in catecholaminergic neurons—is permeable to MPP+ and suggest that this aquaglyceroporin contributes to the selective vulnerability of nigral dopaminergic neurons by providing an entry route for parkinsonogenic toxins. To our knowledge this is the first evidence implicating a toxin permeable membrane channel in the pathophysiology of Parkinson’s disease.
Collapse
MESH Headings
- 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/pharmacokinetics
- Animals
- Aquaporins/genetics
- Disease Models, Animal
- Dopaminergic Neurons/drug effects
- Dopaminergic Neurons/metabolism
- Female
- Gene Deletion
- HEK293 Cells
- Humans
- MPTP Poisoning/genetics
- MPTP Poisoning/metabolism
- MPTP Poisoning/pathology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mutagenesis, Site-Directed
- Neuroprotection/genetics
- Neuroprotective Agents/metabolism
- Parkinson Disease/genetics
- Parkinson Disease/pathology
- Parkinson Disease, Secondary/chemically induced
- Parkinson Disease, Secondary/genetics
- Parkinson Disease, Secondary/metabolism
- Parkinson Disease, Secondary/pathology
- Substantia Nigra/drug effects
- Substantia Nigra/metabolism
- Xenopus laevis
Collapse
Affiliation(s)
- Katja Stahl
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Soulmaz Rahmani
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Agnete Prydz
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Nadia Skauli
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Nanna MacAulay
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Maria N. Mylonakou
- Centre for Molecular Medicine Norway, Nordic EMBL Partnership, Norway Biotechnology Centre, University of Oslo, Oslo, Norway
| | - Reidun Torp
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Øivind Skare
- Department of Occupational Medicine and Epidemiology, National Institute of Occupational Health, Oslo, Norway
| | - Torill Berg
- Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Trygve B. Leergaard
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Ragnhild E. Paulsen
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Oslo, Oslo, Norway
| | - Ole P. Ottersen
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
- Karolinska Institutet, Stockholm, Sweden
| | - Mahmood Amiry-Moghaddam
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
- * E-mail:
| |
Collapse
|
6
|
Myhre O, Låg M, Villanger GD, Oftedal B, Øvrevik J, Holme JA, Aase H, Paulsen RE, Bal-Price A, Dirven H. Early life exposure to air pollution particulate matter (PM) as risk factor for attention deficit/hyperactivity disorder (ADHD): Need for novel strategies for mechanisms and causalities. Toxicol Appl Pharmacol 2018; 354:196-214. [PMID: 29550511 DOI: 10.1016/j.taap.2018.03.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 02/14/2018] [Accepted: 03/12/2018] [Indexed: 12/11/2022]
Abstract
Epidemiological studies have demonstrated that air pollution particulate matter (PM) and adsorbed toxicants (organic compounds and trace metals) may affect child development already in utero. Recent studies have also indicated that PM may be a risk factor for neurodevelopmental disorders (NDDs). A pattern of increasing prevalence of attention deficit/hyperactivity disorder (ADHD) has been suggested to partly be linked to environmental pollutants exposure, including PM. Epidemiological studies suggest associations between pre- or postnatal exposure to air pollution components and ADHD symptoms. However, many studies are cross-sectional without possibility to reveal causality. Cohort studies are often small with poor exposure characterization, and confounded by traffic noise and socioeconomic factors, possibly overestimating the study associations. Furthermore, the mechanistic knowledge how exposure to PM during early brain development may contribute to increased risk of ADHD symptoms or cognitive deficits is limited. The closure of this knowledge gap requires the combined use of well-designed longitudinal cohort studies, supported by mechanistic in vitro studies. As ADHD has profound consequences for the children affected and their families, the identification of preventable risk factors such as air pollution exposure should be of high priority.
Collapse
Affiliation(s)
- Oddvar Myhre
- Department of Toxicology and Risk Assessment, Norwegian Institute of Public Health, Oslo, Norway.
| | - Marit Låg
- Department of Air pollution and Noise, Norwegian Institute of Public Health, Oslo, Norway
| | - Gro D Villanger
- Department of Child Health and Development, Norwegian Institute of Public Health, Oslo, Norway
| | - Bente Oftedal
- Department of Air pollution and Noise, Norwegian Institute of Public Health, Oslo, Norway
| | - Johan Øvrevik
- Department of Air pollution and Noise, Norwegian Institute of Public Health, Oslo, Norway
| | - Jørn A Holme
- Department of Air pollution and Noise, Norwegian Institute of Public Health, Oslo, Norway
| | - Heidi Aase
- Department of Child Health and Development, Norwegian Institute of Public Health, Oslo, Norway
| | - Ragnhild E Paulsen
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Norway
| | - Anna Bal-Price
- European Commission, Joint Research Centre, Ispra, Italy
| | - Hubert Dirven
- Department of Toxicology and Risk Assessment, Norwegian Institute of Public Health, Oslo, Norway
| |
Collapse
|
7
|
Sørvik IB, Solum EJ, Labba NA, Hansen TV, Paulsen RE. Differential effects of some novel synthetic oestrogen analogs on oxidative PC12 cell death caused by serum deprivation. Free Radic Res 2018; 52:273-287. [DOI: 10.1080/10715762.2018.1430363] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Irene B. Sørvik
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
| | - Eirik Johansson Solum
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, Oslo, Norway
| | - Nils A. Labba
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
- PharmaTox Strategic Research Initiative, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Trond Vidar Hansen
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, Oslo, Norway
| | - Ragnhild E. Paulsen
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
- PharmaTox Strategic Research Initiative, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| |
Collapse
|
8
|
|
9
|
Spildrejorde M, Falck M, Leithaug M, Gervin K, Fjerdingstad HB, Nordeng H, Paulsen RE, Eskeland R, Lyle R. Human embryonic stem cells as a model for paracetamol induced epigenetic deregulation and neurotoxicity. Reprod Toxicol 2017. [DOI: 10.1016/j.reprotox.2017.06.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
10
|
Sørvik IB, Paulsen RE. High and low concentration of 17α-estradiol protect cerebellar granule neurons in different time windows. Biochem Biophys Res Commun 2017. [DOI: 10.1016/j.bbrc.2017.06.100] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
11
|
Austdal LPE, Bjørnstad S, Mathisen GH, Aden PK, Mikkola I, Paulsen RE, Rakkestad KE. Glucocorticoid Effects on Cerebellar Development in a Chicken Embryo Model: Exploring Changes in PAX6 and Metalloproteinase-9 After Exposure to Dexamethasone. J Neuroendocrinol 2016; 28. [PMID: 27791298 DOI: 10.1111/jne.12438] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 10/25/2016] [Accepted: 10/25/2016] [Indexed: 12/22/2022]
Abstract
The developing cerebellum is vulnerable to effects of glucocorticoids and cerebellar dysfunction is associated with neurodevelopmental disorders (e.g. autism). Transcription factor PAX6 and matrix metalloproteinase-9 (MMP-9) are critical for normal cerebellar development and are highly expressed in migrating neurones. Alterations in MMP-9 and PAX6 are associated with altered cerebellar development. In the present study, we characterised the growth rate and development of the cortical layers, and further investigated how the levels of PAX6 and MMP-9, as well as glucocorticoid receptor (GR) and proliferating cell nuclear antigen (PCNA), change in the cerebellum during the foetal period [embryonic day (E)12-21] in chicken, which corresponds to the human perinatal period. Dexamethasone (DEX) was administered in ovo at E13 and E16, aiming to investigate how prenatal exposure to glucocorticoids interferes with normal development. DEX reduced foetal and cerebellar weight at E17 in a dose-dependent manner linked to a reduced level of PCNA and, over time, down-regulation of GR. We report that promoter activity of PAX6 and MMP-9 increased as a result of GR-stimulation in vitro. Prenatal DEX increased the protein level of PAX6 in a transient manner. PAX6 is reduced in mature granule neurones, and this occurred earlier in embryos exposed to DEX than in non-exposed controls. DEX exposure also led to a slow-onset down-regulation of MMP-9. Taken together, these findings indicate that excess prenatal glucocorticoid stimulation disturbs normal development of the cerebellum through mechanisms associated with reduced proliferation and accelerated maturation where PAX6 and MMP-9 play important roles.
Collapse
Affiliation(s)
- L P E Austdal
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
| | - S Bjørnstad
- Department of Pathology, Oslo University Hospital - Ullevål, Oslo, Norway
| | - G H Mathisen
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
| | - P K Aden
- Department of Neurosciences for Children, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - I Mikkola
- Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Norway, Tromsø, Norway
| | - R E Paulsen
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
| | - K E Rakkestad
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
| |
Collapse
|
12
|
Bjørnstad S, Samara A, Erichsen A, Paulsen RE, Glover JC, Roald B. Hampered Lung Maturation in Methimazole-Induced Hypothyroidism in Fetal Chicken: Morphological and Molecular Correlates to Human Fetal Development. Neonatology 2016; 110:83-92. [PMID: 27070722 DOI: 10.1159/000444656] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Accepted: 02/11/2016] [Indexed: 11/19/2022]
Abstract
BACKGROUND Molecular understanding of lung development is crucial for developing therapies and diagnostic tools. Animal models with altered thyroid hormone signaling provide mechanistic insight into thyroid-dependent neonatal lung disease. Repression of Klf2 (Krüppel-like factor 2), a suggested T3 target gene, is associated with disrupted lung development in mice. Klf2 is proposed to be specifically involved in type I pneumocyte differentiation. OBJECTIVES To explore mechanisms of thyroid-dependent lung disease, we studied developing chicken fetuses with experimentally induced hypothyroidism. METHODS Morphology and the expression of a panel of molecules linked to Klf2 were assessed using histology, immunohistochemistry, Western blot and qPCR. RESULTS Methimazole injections at E14 hampered lung maturation. The effects of methimazole were evident in several tissue compartments, and impacted on both pneumocyte and vascular differentiation, suggesting cellular and molecular pleiotropy. CONCLUSIONS Concomitant expression changes in a panel of selected microRNAs regulated by Klf2 suggest importance in lung development. These microRNAs may thus represent potential clinical targets and diagnostic and prognostic tools in thyroid-dependent lung disease.
Collapse
Affiliation(s)
- Sigrid Bjørnstad
- Department of Pathology, Oslo University Hospital HF, Ullevx00E5;l, Oslo, Norway
| | | | | | | | | | | |
Collapse
|
13
|
Solum EJ, Cheng JJ, Sørvik IB, Paulsen RE, Vik A, Hansen TV. Synthesis and biological evaluations of new analogs of 2-methoxyestradiol: Inhibitors of tubulin and angiogenesis. Eur J Med Chem 2014; 85:391-8. [DOI: 10.1016/j.ejmech.2014.08.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 07/28/2014] [Accepted: 08/01/2014] [Indexed: 12/20/2022]
|
14
|
Bjørnstad S, Paulsen RE, Erichsen A, Glover JC, Roald B. Type I and II pneumocyte differentiation in the developing fetal chicken lung: conservation of pivotal proteins from birds to human in the struggle for life at birth. Neonatology 2014; 105:112-20. [PMID: 24335141 DOI: 10.1159/000355346] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 08/29/2013] [Indexed: 11/19/2022]
Abstract
BACKGROUND Antenatal corticosteroids and surfactant replacement therapy have dramatically reduced mortality caused by lung disease in premature babies. Knowledge about mechanisms regulating epithelial differentiation of the respiratory membrane is limited, as are effects of pharmacological interventions. The chicken fetus is a valuable model for exploring pharmacological actions on developing organs. However, more precise information about the timing of developmental events in the chicken lung is needed for human correlation. OBJECTIVES Characterization of morphological development and protein expression in the respiratory membrane of the developing chicken lung to create a platform for pharmacological testing in a human context. METHODS Fetal chicken lungs, embryonic days (E) 7-20, were characterized by morphology and protein expression of epithelial differentiation markers. This was compared with publications on the same processes during human lung development. RESULTS The respiratory membranes of developing chicken and human lungs show basic similarities. In chicken, surfactant protein B is expressed in cuboidal type II epithelial cells from E17. Aquaporin 5 is expressed in the epithelium from E7 and selectively in type I pneumocytes from E17. The type I pneumocyte and endothelial marker, caveolin 1, is expressed in the endothelium from E7 to E20. CONCLUSION Despite phylogenetic distance, central aspects of cellular development in the chicken and human lung are similar. The fetal chicken model has important additional advantages to mammalian models, including fetal independence and short incubation, and is thus well suited for in vivo studies of lung maturation relevant to human development.
Collapse
Affiliation(s)
- Sigrid Bjørnstad
- Department of Pathology, Oslo University Hospital HF, Ullevål, Oslo, Norway
| | | | | | | | | |
Collapse
|
15
|
Åstrand OAH, Austdal LPE, Paulsen RE, Hansen TV, Rongved P. Synthesis and characterization of new selective Zn2+ fluorescent probes for functionalization: in vitro Cell imaging applications. Tetrahedron 2013. [DOI: 10.1016/j.tet.2013.07.049] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
|
16
|
Mathisen GH, Yazdani M, Rakkestad KE, Aden PK, Bodin J, Samuelsen M, Nygaard UC, Goverud IL, Gaarder M, Løberg EM, Bølling AK, Becher R, Paulsen RE. Prenatal exposure to bisphenol A interferes with the development of cerebellar granule neurons in mice and chicken. Int J Dev Neurosci 2013; 31:762-9. [DOI: 10.1016/j.ijdevneu.2013.09.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 09/12/2013] [Accepted: 09/23/2013] [Indexed: 11/30/2022] Open
Affiliation(s)
- Gro H. Mathisen
- Department of Pharmaceutical BiosciencesUniversity of OsloP.O. Box 1068BlindernN‐0316OsloNorway
| | - Mazyar Yazdani
- Department of Pharmaceutical BiosciencesUniversity of OsloP.O. Box 1068BlindernN‐0316OsloNorway
- Department of BiologyUniversity of OsloP.O. Box 1066 BlindernN‐0316OsloNorway
| | - Kirsten E. Rakkestad
- Department of Pharmaceutical BiosciencesUniversity of OsloP.O. Box 1068BlindernN‐0316OsloNorway
| | - Petra K. Aden
- Department of Neurosciences for ChildrenOslo University HospitalP.O. Box 4950 Nydalen0424OsloNorway
| | - Johanna Bodin
- Division of Environmental MedicineNorwegian Institute of Public HealthP.O. Box 4404 Nydalen0403OsloNorway
| | - Mari Samuelsen
- Division of Environmental MedicineNorwegian Institute of Public HealthP.O. Box 4404 Nydalen0403OsloNorway
| | - Unni C. Nygaard
- Division of Environmental MedicineNorwegian Institute of Public HealthP.O. Box 4404 Nydalen0403OsloNorway
| | - Ingeborg L. Goverud
- Department of PathologyUllevål University HospitalUniversity of OsloP.O. Box 4950 Nydalen0424OsloNorway
| | - Mona Gaarder
- Department of Pharmaceutical BiosciencesUniversity of OsloP.O. Box 1068BlindernN‐0316OsloNorway
| | - Else Marit Løberg
- Department of PathologyUllevål University HospitalUniversity of OsloP.O. Box 4950 Nydalen0424OsloNorway
| | - Anette K. Bølling
- Division of Environmental MedicineNorwegian Institute of Public HealthP.O. Box 4404 Nydalen0403OsloNorway
| | - Rune Becher
- Division of Environmental MedicineNorwegian Institute of Public HealthP.O. Box 4404 Nydalen0403OsloNorway
| | - Ragnhild E. Paulsen
- Department of Pharmaceutical BiosciencesUniversity of OsloP.O. Box 1068BlindernN‐0316OsloNorway
| |
Collapse
|
17
|
Åstrand OAH, Aziz G, Ali SF, Paulsen RE, Hansen TV, Rongved P. Synthesis and initial in vitro biological evaluation of two new zinc-chelating compounds: Comparison with TPEN and PAC-1. Bioorg Med Chem 2013; 21:5175-81. [DOI: 10.1016/j.bmc.2013.06.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 06/12/2013] [Accepted: 06/14/2013] [Indexed: 12/19/2022]
|
18
|
Aziz G, Odlo K, Hansen TV, Paulsen RE, Mathisen GH. Combretastatin A-4 and structurally related triazole analogues induce caspase-3 and reactive oxygen species-dependent cell death in PC12 cells. Eur J Pharmacol 2013; 703:25-32. [DOI: 10.1016/j.ejphar.2013.01.043] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 01/18/2013] [Accepted: 01/29/2013] [Indexed: 11/27/2022]
|
19
|
Boldingh Debernard KA, Mathisen GH, Paulsen RE. Differences in NGFI-B, Nurr1, and NOR-1 expression and nucleocytoplasmic translocation in glutamate-treated neurons. Neurochem Int 2012; 61:79-88. [PMID: 22525717 DOI: 10.1016/j.neuint.2012.04.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 03/21/2012] [Accepted: 04/05/2012] [Indexed: 11/30/2022]
Abstract
NGFI-B (NR4A1, Nur77 or TR3) together with Nurr1 (NR4A2) and NOR-1 (NR4A3) constitute the NR4A subgroup of orphan nuclear receptors. They play critical roles in proliferation, differentiation, survival and apoptosis in different cell types, including neurons, immature T-cells, and different cancer cells. As ligand-independent and constitutively active receptors, the diverse biological activities of NGFI-B, Nurr1 and NOR-1 depend on their levels of expression, post-translational modifications and subcellular localization. Nuclear localization of the NR4A proteins leads to transcriptional activity, whereas NGFI-B and recently also NOR-1 have been shown to induce apoptosis by a more direct mechanism when localized at mitochondria. In the present study we investigated mRNA expression and subcellular translocation of the NR4A proteins during glutamate excitotoxicity in rat cerebellar granule neurons. NGFI-B and Nurr1 mRNA, but not NOR-1 mRNA, were induced by treatments associated with calcium influx, although their regulation seemed to be different. NR4A(gfp) fusion proteins showed a predominant nuclear localization in untreated cells. After glutamate treatment NGFI-B(gfp) translocated to cytosol and mitochondria within a few hours, whereas Nurr1(gfp) translocation was delayed, and NOR-1(gfp) mainly stayed in the nucleus. Subcellular targeting of NGFI-B seems to be tightly regulated, as a single mutation of threonine 142 altered NGFI-B(gfp) localization. Differences in expression and subcellular translocation of NGFI-B, Nurr1, and NOR-1 may reflect different functions in neurons in glutamate excitotoxicity.
Collapse
|
20
|
Strøm BO, Paulsen RE. Apoptosis inducer NGFI-B is degraded by the proteasome and stabilized by treatment with EGF. Biochem Biophys Res Commun 2012; 417:1292-7. [PMID: 22234305 DOI: 10.1016/j.bbrc.2011.12.132] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 12/25/2011] [Indexed: 11/26/2022]
Abstract
NGFI-B is a nuclear receptor and immediate early gene that is upregulated in many different tumour cell lines. As it is involved in cell death and survival, it has been suggested as a target for anti-cancer drugs. The protein level of NGFI-B is important for its functions and may be regulated through induction or stabilization. NGFI-B protein stability was studied using the protein synthesis inhibitor cycloheximide in CV1 cells transiently transfected with NGFI-B. Inhibiting the proteasome with MG132 stabilized NGFI-B, indicating that the proteasome is responsible for break-down of NGFI-B, as it is for many nuclear receptors. In order to determine regions responsible for the break-down of NGFI-B two N-terminal regions with high PEST-scores were deleted. Deletion of amino acids 122-195 containing a PEST-sequence which includes an ERK2 phosphorylation target, gave a more stable protein. In addition, treatment of the cells with the ERK2 activator EGF increased the stability of wild type NGFI-B. We then tested whether a mutation at threonine 142 influenced the stability of NGFI-B. We found that the phosphorylation-mimicking mutant NGFI-B T142E had an increased stability, while the non-phosphorylable mutant (T142A) showed similar stability to the wild type. Thus, EGF-stimulation of cells may be a mechanism for priming the cells for effects of NGFI-B by increasing its stability.
Collapse
Affiliation(s)
- Bjørn O Strøm
- Department of Pharmaceutical Biosciences, University of Oslo, P.O. Box 1068 Blindern, N-0316 Oslo, Norway
| | | |
Collapse
|
21
|
Bølling AK, Ovrevik J, Samuelsen JT, Holme JA, Rakkestad KE, Mathisen GH, Paulsen RE, Korsnes MS, Becher R. Mono-2-ethylhexylphthalate (MEHP) induces TNF-α release and macrophage differentiation through different signalling pathways in RAW264.7 cells. Toxicol Lett 2011; 209:43-50. [PMID: 22143055 DOI: 10.1016/j.toxlet.2011.11.016] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 11/18/2011] [Accepted: 11/19/2011] [Indexed: 11/16/2022]
Abstract
Epidemiological studies have associated indoor phthalate exposure with increased incidences and severity of asthma in children and adults, and inflammatory effects have been suggested as a possible mechanism. Recent studies report that phthalates may activate mitogen-activated protein (MAP) kinase p38 and various peroxisome proliferator-activated receptor (PPAR) isoforms. Here we confirm and extend these findings by investigating possible signalling pathways activated in the murine monocyte-macrophage cell line RAW264.7, using mono-2-ethylhexylphthalate (MEHP) as a model compound. MEHP exposure (0.3-1.0 mM) for 3h increased tumour necrosis factor (TNF)-α release and changed the cellular morphology into elongated spindle-like appearance, resembling more differentiated anti-inflammatory macrophages (M2). This was accompanied by increased expression of the macrophage differentiation marker CD163. Western analysis showed phosphorylation of p38 and Akt after 30 min exposure. Experiments using specific inhibitors suggested that MEHP-induced activation of both p38 and the phosphoinositide-3 (PI3) kinase/Akt pathway were involved in the release of TNF-α; whereas only PI3kinase seemed to be involved in differentiation. In contrast, inhibitors of PPARα and γ reduced differentiation, but did not affect TNF-α release. In conclusion, MEHP induced cytokine release and triggered differentiation of RAW264.7 cells, possibly into M2-like macrophages, but different signalling pathways appear to be involved in these responses.
Collapse
Affiliation(s)
- Anette Kocbach Bølling
- Division of Environmental Medicine, Norwegian Institute of Public Health, P.O. Box 4404 Nydalen, N-0403 Oslo, Norway.
| | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Aden P, Paulsen RE, Mæhlen J, Løberg EM, Goverud IL, Liestøl K, Lømo J. Glucocorticoids dexamethasone and hydrocortisone inhibit proliferation and accelerate maturation of chicken cerebellar granule neurons. Brain Res 2011; 1418:32-41. [DOI: 10.1016/j.brainres.2011.08.053] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Revised: 07/27/2011] [Accepted: 08/22/2011] [Indexed: 11/16/2022]
|
23
|
Strøm BO, Aden P, Mathisen GH, Lømo J, Davanger S, Paulsen RE. Transfection of chicken cerebellar granule neurons used to study glucocorticoid receptor regulation by nuclear receptor 4A (NR4A). J Neurosci Methods 2010; 193:39-46. [DOI: 10.1016/j.jneumeth.2010.08.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 07/30/2010] [Accepted: 08/08/2010] [Indexed: 10/19/2022]
|
24
|
Aziz G, Akselsen ØW, Hansen TV, Paulsen RE. Procaspase-activating compound 1 induces a caspase-3-dependent cell death in cerebellar granule neurons. Toxicol Appl Pharmacol 2010; 247:238-42. [PMID: 20638399 DOI: 10.1016/j.taap.2010.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 06/16/2010] [Accepted: 07/04/2010] [Indexed: 11/26/2022]
Abstract
Procaspase-activating compound 1, PAC-1, has been introduced as a direct activator of procaspase-3 and has been suggested as a therapeutic agent against cancer. Its activation of procaspase-3 is dependent on the chelation of zinc. We have tested PAC-1 and an analogue of PAC-1 as zinc chelators in vitro as well as their ability to activate caspase-3 and induce cell death in chicken cerebellar granule neuron cultures. These neurons are non-dividing, primary cells with normal caspase-3. The results reported herein show that PAC-1 chelates zinc, activates procaspase-3, and leads to caspase-3-dependent cell death in neurons, as the specific caspase-3-inhibitor Ac-DEVD-cmk inhibited both the caspase-3 activity and cell death. Thus, chicken cerebellar granule neurons is a suitable model to study mechanisms of interference with apoptosis of PAC-1 and similar compounds. Furthermore, the present study also raises concern about potential neurotoxicity of PAC-1 if used in cancer therapy.
Collapse
Affiliation(s)
- Gulzeb Aziz
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Norway
| | | | | | | |
Collapse
|
25
|
Rakkestad KE, Holme JA, Paulsen RE, Schwarze PE, Becher R. Mono(2-ethylhexyl) phthalate induces both pro- and anti-inflammatory responses in rat alveolar macrophages through crosstalk between p38, the lipoxygenase pathway and PPARalpha. Inhal Toxicol 2010; 22:140-50. [PMID: 19938896 DOI: 10.3109/08958370903019885] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Airway inflammation is important in asthma pathogenesis. Recent epidemiological data have indicated an association between asthma symptoms in children and exposure to di(2-ethylhexyl) phthalate (DEHP). Thus, we have studied inflammatory responses in primary rat alveolar macrophages (AMs) after exposure to mono(2-ethylhexyl) phthalate (MEHP), the major primary metabolite of DEHP. First, we show that MEHP induces a dose-dependent release of the pro-inflammatory tumour necrosis factor-alpha (TNF-alpha) in AMs, giving a maximal (5-fold) increase at 0.7 mM. This concentration also induced some cell death. MEHP also induced phosphorylation of MAPK p38, while the p38 inhibitor SB 202190 reduced MEHP-induced TNF-alpha, suggesting a p38-dependent cytokine production. Next, we elucidated possible effects of MEHP on the 5-lipoxygenase (5-LO) pathway and found that MEHP caused increased leukotriene (LTB(4)) release. Further, we found that the 5-LO inhibitor nordihydrogualaretic acid (NDGA) significantly reduced both MEHP-induced TNF-alpha release and MEHP-induced formation of reactive oxygen species (ROS), supporting an involvement of the 5-LO pathway in MEHP induced inflammatory reactions. Last, we found that MK-886, a known inhibitor of peroxisome proliferator-activated receptor alpha (PPARalpha), increased the MEHP-induced TNF-alpha response. This indicates that MEPH-PPARalpha binding mediates an anti-inflammatory signal.
Collapse
Affiliation(s)
- Kirsten E Rakkestad
- Department of Air Pollution and Noise, Division of Environmental Medicine, Norwegian Institute of Public Health, Oslo, Norway
| | | | | | | | | |
Collapse
|
26
|
Aden P, Goverud I, Liestøl K, Løberg EM, Paulsen RE, Maehlen J, Lømo J. Low-potency glucocorticoid hydrocortisone has similar neurotoxic effects as high-potency glucocorticoid dexamethasone on neurons in the immature chicken cerebellum. Brain Res 2008; 1236:39-48. [PMID: 18706896 DOI: 10.1016/j.brainres.2008.07.095] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Revised: 06/20/2008] [Accepted: 07/18/2008] [Indexed: 11/15/2022]
Abstract
High-potency glucocorticoids (GC) are used in the prophylaxis and treatment of neonatal bronchopulmonal dysplasia, but there is concern about side effects on the developing brain. Recently, the low-potency GC hydrocortisone (HC) has been suggested as an alternative to high-potency GC. We compared the neurotoxic effects of HC with the high-potency GC dexamethasone (DEX) in chicken cerebellum. A single dose of GC was injected into the egg at embryonic day 16 and the death of granule neurons in histologic sections of the cerebellar cortex was examined 24 h later. DEX and HC showed a similar dose-dependent induction of morphological apoptosis and caspase-3 activation in the internal granular layer. A doubling of the apoptosis rate compared to the basal rate was seen for the highest dose of DEX (5 mg/kg) and medium dose of HC (1 mg/kg). In cultures of embryonic chicken cerebellar granule cells, DEX and HC increased cell death and induced rapid caspase-3 activation in a similar dose-dependent manner. Transfection of granule cells with a luciferase reporter gene revealed that the dose needed for the activation of gene transcription (classical signalling pathway) with DEX was much lower than for HC. In conclusion, HC does not present itself as a safer drug than DEX in this model. In addition, it appears that DEX and HC induce apoptosis in immature granule neurons via a non-genomic (non-classical) mechanism.
Collapse
Affiliation(s)
- Petra Aden
- Department of Pathology, Ullevål University Hospital, N-0407 Oslo, Norway.
| | | | | | | | | | | | | |
Collapse
|
27
|
Mathisen GH, Thorkildsen IH, Paulsen RE. Secretory PLA2-IIA and ROS generation in peripheral mitochondria are critical for neuronal death. Brain Res 2007; 1153:43-51. [PMID: 17462609 DOI: 10.1016/j.brainres.2007.03.067] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2006] [Revised: 03/16/2007] [Accepted: 03/21/2007] [Indexed: 12/21/2022]
Abstract
In this study the role of mitochondrial secretory PLA2-IIA in glutamate-induced cell death in cultured cerebellar granule neurons has been investigated. Inhibition of secretory PLA2-IIA blocked glutamate-induced cell death. Since PLA2 may generate reactive oxygen species (ROS), we have investigated ROS production, detected as dihydrorhodamine 123 oxidation and nitrotyrosine modifications of proteins, following glutamate treatment in the absence or presence of an inhibitor of secretory PLA2-IIA. There was an increased generation of ROS in both glutamate- and buffer-treated neurons compared to untreated neurons. Scavenging with dihydrorhodamine 123 reduced glutamate-induced death (60%), showing that ROS detected in glutamate-treated neurons were associated with cell death. However, ROS detected in buffer-treated neurons were not associated with toxicity. Glutamate treatment led to ROS production predominantly in peripheral mitochondria, whereas buffer treatment led to ROS production in somal mitochondria. Inhibition of secretory PLA2-IIA (i) reduced the generation of ROS after glutamate treatment, (ii) reduced the ROS production in peripheral mitochondria in glutamate-treated neurons, consistent with the fact that calcium entry through glutamate (NMDA) receptors has a privileged access to peripheral mitochondria, and (iii) did not reduce the generation of ROS after buffer treatment. In conclusion, activation of NMDA receptors induces ROS, which is critical for neuronal death, due to secretory PLA2-IIA associated with peripheral mitochondria.
Collapse
Affiliation(s)
- Gro H Mathisen
- Department of Pharmaceutical Biosciences, University of Oslo, Blindern, N-0316 Oslo, Norway
| | | | | |
Collapse
|
28
|
Fallgren AB, Mathisen GH, Maehlen J, Blomhoff R, Paulsen RE. Preconditioning with estradiol abolishes its neuroprotection in cerebellar neurons. Biochem Biophys Res Commun 2007; 352:966-72. [PMID: 17157803 DOI: 10.1016/j.bbrc.2006.11.139] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Accepted: 11/29/2006] [Indexed: 11/21/2022]
Abstract
Certain steroids are neuroprotective because they are modulators of neuronal activity or ROS scavengers. We examined neuroprotection following glutamate-induced excitotoxicity in cerebellar granule neuron cultures. 17beta-Estradiol, 17alpha-estradiol (nonestrogenic), or vitamins C+E were equally neuroprotective when coadministered with glutamate, consistent with protection by ROS scavenging. Progesterone protected mainly by an action on GABA-A receptors. Since exogenous antioxidants may influence the level of glutathione, the main endogenous antioxidant in neurons, we investigated if a preconditioning period with the neuroprotectors changed their efficacy as protectors. The neuroprotection by 17beta-estradiol and 17alpha-estradiol, but not progesterone or vitamins C+E, was almost abolished following a preconditioning period of 24h. This reduction was accompanied by an inhibition of the gamma-glutamylcysteine synthetase promoter, and a reduced level of glutathione when preconditioning was combined with the subsequent glutamate exposure. Thus, vitamins C+E and progesterone were more effective long-term neuroprotectors, since preconditioning did not reduce glutathione.
Collapse
Affiliation(s)
- Asa B Fallgren
- Department of Pharmaceutical Biosciences, University of Oslo, P.O. Box 1068 Blindern, N-0316 Oslo, Norway
| | | | | | | | | |
Collapse
|
29
|
Jacobs CM, Aden P, Mathisen GH, Khuong E, Gaarder M, Løberg EM, Lømo J, Maehlen J, Paulsen RE. Chicken cerebellar granule neurons rapidly develop excitotoxicity in culture. J Neurosci Methods 2006; 156:129-35. [PMID: 16564575 DOI: 10.1016/j.jneumeth.2006.02.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 02/10/2006] [Accepted: 02/13/2006] [Indexed: 01/22/2023]
Abstract
Rat cerebellar granule cell culture is widely used as a model to study factors that control neuronal differentiation and death (e.g. excitotoxicity). However, a main drawback of this model is its dependence on depolarizing culture condition (25 mM potassium). In addition, it is quite expensive to maintain and requires animal facilities. Here we report that cerebellar granule neuron cultures from chicken may be used as an alternative model to study excitotoxicity. Surprisingly, fetal chicken cells may be grown in a physiological potassium concentration (5 mM potassium). They develop excitotoxicity rapidly in culture (fully developed at 3 days in vitro), and respond to glutamate excitotoxicity similar to rat cultures (ROS production and activation of caspase-3).
Collapse
Affiliation(s)
- Chris M Jacobs
- Department of Pharmaceutical Biosciences, University of Oslo, Norway
| | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Jacobs CM, Trinh MD, Rootwelt T, Lømo J, Paulsen RE. Dexamethasone induces cell death which may be blocked by NMDA receptor antagonists but is insensitive to Mg2+ in cerebellar granule neurons. Brain Res 2006; 1070:116-23. [PMID: 16403471 DOI: 10.1016/j.brainres.2005.10.093] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2005] [Revised: 10/18/2005] [Accepted: 10/20/2005] [Indexed: 11/20/2022]
Abstract
Since dexamethasone may elevate the Ca2+ influx through NMDA receptors, we have investigated mechanisms of dexamethasone toxicity in rat cerebellar granule neurons. Dexamethasone concentrations over 0.1 microM induced cell death that reached about 20% of the death induced by glutamate. Dexamethasone-induced cell death was reduced by more than 80% by the mineralocorticoid antagonist RU 28318 or the NMDA receptor antagonists MK 801 and CGP 39551, whereas RU 28318 rescued only approximately 30% of cells treated with glutamate, indicating that dexamethasone requires NMDA receptors to induce acute neuronal toxicity and that a fraction of the neurons showed this toxicity. Mg2+ reduced the cell death induced by glutamate at potassium concentrations of 1 mM and 5 mM, but not at 25 mM. In contrast, cell death induced by dexamethasone was not significantly reduced by Mg2+ in any of the potassium concentrations. Both glutamate and dexamethasone induced toxicity with translocation of the apoptosis inducer NGFI-B to the mitochondria seen after 30 min-2 h concomitant with activation of apoptosis inducing factor (AIF) and caspase-3. In conclusion, dexamethasone induces a rapid toxicity which is blocked by NMDA receptor antagonists other than Mg2+, and involves mitochondrial apoptosis inducer NGFI-B.
Collapse
Affiliation(s)
- Chris M Jacobs
- Department of Pharmaceutical Biosciences, Ullevål University Hospital, University of Oslo, P.O. Box 1068 Blindern, N-0316 Oslo, Norway
| | | | | | | | | |
Collapse
|
31
|
Jacobs CM, Paulsen RE. Crosstalk between ERK2 and RXR regulates nuclear import of transcription factor NGFI-B. Biochem Biophys Res Commun 2005; 336:646-52. [PMID: 16140267 DOI: 10.1016/j.bbrc.2005.08.143] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Accepted: 08/17/2005] [Indexed: 11/21/2022]
Abstract
Transcription factor NGFI-B initiates apoptosis when allowed to translocate to mitochondria. Retinoid-X receptor (RXR), another member of the nuclear receptor family, regulates NGFI-B signaling through heterodimerization and nuclear export. Growth factor EGF activates ERK2, which phosphorylates NGFI-B and determines if NGFI-B is allowed to translocate to mitochondria. In the present study, EGF treatment resulted in an increased nuclear import of NGFI-B. Likewise, active ERK2 resulted in a preferential nuclear localization of NGFI-B. When coexpressed with RXR the nuclear import and nuclear localization induced by active ERK2 were strongly reduced. In the presence of its ligand 9-cis-retinoic acid, RXR no longer inhibited ERK2-induced nuclear import. Thus, RXR serves a permissive role for ERK2-mediated nuclear accumulation of NGFI-B. This finding represents a novel crosstalk between ERK2 and RXR signaling pathways, and explains how two independent inhibitors of apoptosis (EGF and 9-cis-retinoic acid) may cooperate to regulate nuclear targeting of apoptosis inducer NGFI-B.
Collapse
Affiliation(s)
- Chris M Jacobs
- Department of Pharmaceutical Biosciences, University of Oslo, Norway
| | | |
Collapse
|
32
|
Rosseland CM, Wierød L, Oksvold MP, Werner H, Ostvold AC, Thoresen GH, Paulsen RE, Huitfeldt HS, Skarpen E. Cytoplasmic retention of peroxide-activated ERK provides survival in primary cultures of rat hepatocytes. Hepatology 2005; 42:200-7. [PMID: 15962331 DOI: 10.1002/hep.20762] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Reactive oxygen species (ROS) are implicated in tissue damage causing primary hepatic dysfunction following ischemia/reperfusion injury and during inflammatory liver diseases. A potential role of extracellular signal-regulated kinase (ERK) as a mediator of survival signals during oxidative stress was investigated in primary cultures of hepatocytes exposed to ROS. Hydrogen peroxide (H(2)O(2)) induced a dose-dependent activation of ERK, which was dependent on MEK activation. The ERK activation pattern was transient compared with the ERK activation seen after stimulation with epidermal growth factor (EGF). Nuclear accumulation of ERK was found after EGF stimulation, but not after H(2)O(2) exposure. A slow import/rapid export mechanism was excluded through the use of leptomycin B, an inhibitor of nuclear export sequence-dependent nuclear export. Reduced survival of hepatocytes during ROS exposure was observed when ERK activation was inhibited. Ribosomal S6 kinase (RSK), a cytoplasmic ERK substrate involved in cell survival, was activated and located in the nucleus of H(2)O(2)-exposed hepatocytes. The activation was abolished when ERK was inhibited with U0126. In conclusion, our results indicate that activity of ERK in the cytoplasm is important for survival during oxidative stress in hepatocytes and that RSK is activated downstream of ERK. Supplementary material for this article can be found on the HEPATOLOGY website (http://www.interscience.wiley.com/jpages/0270-9139/suppmat/index.html).
Collapse
Affiliation(s)
- Carola M Rosseland
- Laboratory for Toxicopathology, Institute of Pathology, Rikshospitalet University Hospital, Norway
| | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Jacobs CM, Boldingh KA, Slagsvold HH, Thoresen GH, Paulsen RE. ERK2 Prohibits Apoptosis-induced Subcellular Translocation of Orphan Nuclear Receptor NGFI-B/TR3. J Biol Chem 2004; 279:50097-101. [PMID: 15448159 DOI: 10.1074/jbc.m409145200] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transcription factor NGFI-B (neuronal growth factor-induced clone B), also called Nur77 or TR3, is an immediate early gene and an orphan member of the nuclear receptor family. The NGFI-B protein also has a function distinct from that of a transcription factor; it translocates to mitochondria to initiate apoptosis. Recently, it was demonstrated that NGFI-B interacts with Bcl-2 by inducing a conformational change in Bcl-2, converting it from protector to a killer. After exposing rat cerebellar granule neurons to glutamate (100 mum, 15 min), NGFI-B translocated to the mitochondria. Growth factors such as the epidermal growth factor activate the MAP kinase ERK, the activity of which may determine whether a cell survives or undergoes apoptosis. In the present study we found that the epidermal growth factor activated ERK2 in cerebellar granule neurons and that this activation prohibited glutamate-induced subcellular translocation of NGFI-B. Likewise, overexpressed active ERK2 resulted in a predominant nuclear localization of green fluorescent protein-tagged NGFI-B. Thus, activation of ERK2 may overcome apoptosis-induced subcellular translocation of NGFI-B. This finding represents a novel and rapid growth factor survival pathway that is independent of gene regulation.
Collapse
Affiliation(s)
- Chris M Jacobs
- Institute of Pharmacy, University of Oslo, N-0316 Oslo, Norway
| | | | | | | | | |
Collapse
|
34
|
Slagsvold HH, Østvold AC, Fallgren AB, Paulsen RE. Nuclear receptor and apoptosis initiator NGFI-B is a substrate for kinase ERK2. Biochem Biophys Res Commun 2002; 291:1146-50. [PMID: 11883936 DOI: 10.1006/bbrc.2002.6579] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
NGFI-B is an inducible orphan nuclear receptor that initiates apoptosis. Growth factors such as EGF activate the MAP kinase ERK, whose activity may determine if a cell survives or undergoes apoptosis. EGF stimulation of cells leads to phosphorylation of threonine in NGFI-B. Thr-142 of NGFI-B is comprised in a consensus MAP kinase site and was identified as a preferred substrate for ERK2 (but not ERK1) in vitro. These results suggest that NGFI-B may be a molecular target for ERK2 signals and thereby a substrate for crosstalk between a growth factor survival pathway and an inducible regulator of apoptosis.
Collapse
Affiliation(s)
- Hege H Slagsvold
- Institute of Pharmacy, University of Oslo, P.O. Box 1068 Blindern, N-0316 Oslo, Norway
| | | | | | | |
Collapse
|
35
|
Oksvold MP, Skarpen E, Wierød L, Paulsen RE, Huitfeldt HS. Re-localization of activated EGF receptor and its signal transducers to multivesicular compartments downstream of early endosomes in response to EGF. Eur J Cell Biol 2001; 80:285-94. [PMID: 11370743 DOI: 10.1078/0171-9335-00160] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The rapid internalization of receptor tyrosine kinases after ligand binding has been assumed to be a negative modulation of signal transduction. However, accumulating data indicate that signal transduction from internalized cell surface receptors also occurs from endosomes. We show that a substantial fraction of tyrosine-phosphorylated epidermal growth factor receptor (EGFR) and Shc, Grb2 and Cbl after internalization relocates from early endosomes to compartments which are negative for the early endosomes, recycling vesicle markers EEA1 and transferrin in EGF-stimulated cells. These compartments contained the multivesicular body and late endosome marker CD63, and the late endosome and lysosome marker LAMP-1, and showed a multivesicular morphology. Subcellular fractionation revealed that activated EGFR, adaptor proteins and activated ERK 1 and 2 were located in EEA1-negative and LAMP-1-positive fractions. Co-immunoprecipitations showed EGFR in complex with both Shc, Grb2 and Cbl. Treatment with the weak base chloroquine or inhibitors of lysosomal enzymes after EGF stimulation induced an accumulation of tyrosine-phosphorylated EGFR and Shc in EEA1-negative and CD63-positive vesicles after a 120-min chase period. This was accompanied by a sustained activation of ERK 1 and 2. These results suggest that EGFR signaling is not spatially restricted to the plasma membrane, primary vesicles and early endosomes, but is continuing from late endocytic trafficking organelles maturing from early endosomes.
Collapse
Affiliation(s)
- M P Oksvold
- Institute of Pathology, The National Hospital, University of Oslo, Norway.
| | | | | | | | | |
Collapse
|
36
|
Slagsvold HH, Marvik OJ, Eidem G, Kristoffersen N, Paulsen RE. Detection of high molecular weight DNA fragments characteristic of early stage apoptosis in cerebellar granule cells exposed to glutamate. Exp Brain Res 2000; 135:173-8. [PMID: 11131501 DOI: 10.1007/s002210000521] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In cerebellar granule cells a rapid necrotic cell death has been observed during and immediately after glutamate exposure, followed by a delayed apoptotic type of neuronal death in a subpopulation of the surviving neurons. In some experimental models the DNA fragmentation characteristic of apoptosis is readily detected. In other systems apoptosis may occur only in a limited number of cells, rendering DNA fragmentation undetectable using conventional DNA-staining techniques (e.g., ethidium bromide). We have used a sensitive and non-radioactive method for labeling, detection, and quantification of high molecular weight (HMW) DNA fragments. This method is based on the introduction of thymine dimers into DNA after separation by pulse field gel electrophoresis, followed by detection with thymine dimer specific antibodies. Applying this method to cerebellar granule cells in culture, we detected an increase in the amount of HMW DNA fragments characteristic of apoptosis as early as 4 h after glutamate exposure. The N-methyl-D-aspartic acid (NMDA)-receptor antagonist MK801 protected against the fragmentation, whereas no protection was observed using the non-NMDA-receptor antagonist CNQX.
Collapse
|
37
|
Paulsen RE, Ottersen OP. [Glutamate, apoptosis and necrosis of the nervous system]. Tidsskr Nor Laegeforen 2000; 120:63-4. [PMID: 10815484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
|
38
|
Abstract
3-Nitropropionic acid (NPA), an inhibitor of succinate dehydrogenase, is dietary neurotoxin. It is not known if neurons and astrocytes differ in their vulnerability to NPA, therefore, we investigated its toxicity in primary cultures of cerebellar granule cells and astrocytes. NPA inhibited succinate dehydrogenase and tricarboxylic acid cycle activity to the same degree in neurons and astrocytes. Even so NPA acid was 16 times more toxic to neurons than to astrocytes (LC50: 0.7 and 11 mM, respectively). The neurotoxicity of NPA was mediated by NMDA-receptor activation, calcium influx, and formation of reactive oxygen species, as revealed by the protective effect of NMDA-receptor blockade, the accumulation of 45Ca, and the protective effect of N-t-butyl-alpha-phenylnitron (PBN), a scavenger of reactive oxygen species. Cytotoxic concentrations of NPA caused a reduction in the intracellular level of glutathione, which probably contributed to the oxidative damage in both neurons and astrocytes. The relative resistance of astrocytes to NPA appeared to be related to their low tricarboxylic acid cycle activity (5%-10% of that in neurons) and to the inability of NPA to cause astrocytic calcium overload. We conclude that NPA acid predominantly is an astrocyte-sparing neurotoxin.
Collapse
Affiliation(s)
- C Olsen
- Norwegian Defence Research Establishment, Division for Environmental Toxicology, Kjeller, Norway
| | | | | | | | | |
Collapse
|
39
|
Myhrer T, Paulsen RE. Infusion of D-cycloserine into temporal-hippocampal areas and restoration of mnemonic function in rats with disrupted glutamatergic temporal systems. Eur J Pharmacol 1997; 328:1-7. [PMID: 9203560 DOI: 10.1016/s0014-2999(97)83019-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Partial transections of the fiber connections between the temporal cortex and the lateral entorhinal cortex at a site of the white matter corresponding to the perirhinal cortex result in impaired visual memory accompanied by reduced concentrations of glutamate in both the temporal cortex and lateral entorhinal cortex. Intraperitoneal administration of the glycinergic receptor agonist D-cycloserine produces complete restoration of memory function, as measured by a brightness discrimination task in rats with temporal cortex/lateral entorhinal cortex transections. The purpose of the present study was to identify in which brain structures the compensatory activity might take place. The results show that infusion of cycloserine into either the temporal cortex or lateral entorhinal cortex fully ameliorated the impairment of temporal cortex/lateral entorhinal cortex lesions, whereas infusion into the hippocampal region caused only a mild improvement of the retention performance. Infusion of cycloserine into the frontal cortex or saline into the temporal cortex or lateral entorhinal cortex had no ameliorating effects on the memory dysfunction of rats bearing temporal cortex/lateral entorhinal cortex transections. It is concluded that the temporal cortex, lateral entorhinal cortex and perirhinal cortex are highly critical in forming visual memory.
Collapse
Affiliation(s)
- T Myhrer
- Norwegian Defence Research Establishment, Division for Environmental Toxicology, Kjeller
| | | |
Collapse
|
40
|
Ciani E, Rizzi S, Paulsen RE, Contestabile A. Chronic pre-explant blockade of the NMDA receptor affects survival of cerebellar granule cells explanted in vitro. Brain Res Dev Brain Res 1997; 99:112-7. [PMID: 9088572 DOI: 10.1016/s0165-3806(96)00187-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Rat pups were treated with the competitive NMDA antagonist CGP 39551 with daily injections on postnatal days 1 to 8. Cultures of cerebellar granule cells were prepared from these pups as well as from control pups of the same age and body weight. Granule neurons explanted from CGP 39551-treated pups showed a decreased survival, both at short (2 days) or longer (8 days) time in vitro, irrespective of trophic (high K+) or non-trophic (low K+) culture conditions. Granule cells from control or treated animals underwent apoptotic death when shifted from high to low K+ after maturation in vitro and were rescued by lithium (5 mM). Under the same experimental conditions, the block of protein synthesis through cycloheximide only partially protected from apoptotic death granule neurons from control rats, whereas it was totally effective on cultures derived from CGP 39551-treated animals. This suggests that a different balance between apoptotic/necrotic cell death may be the result of the same experimental conditions in the two types of cultures. Finally, the acquisition of excitotoxic sensitivity to glutamate and the protection given by MK-801 were the same in both types of cultures. The present results demonstrate that the previous block of the NMDA receptor negatively affects the subsequent survival of granule cells once they are explanted in vitro, whereas some features related to the maturation of these neurons in vitro are not impaired.
Collapse
Affiliation(s)
- E Ciani
- Department of Biology, University of Bologna, Italy
| | | | | | | |
Collapse
|
41
|
Ciani E, Grøneng L, Voltattorni M, Rolseth V, Contestabile A, Paulsen RE. Inhibition of free radical production or free radical scavenging protects from the excitotoxic cell death mediated by glutamate in cultures of cerebellar granule neurons. Brain Res 1996; 728:1-6. [PMID: 8864290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Glutamate kills sensitive neurons through several steps downstream to receptor activation: increased free Ca2+ levels, activation of various enzymes and accumulation of reactive oxygen species (ROS). We have evaluated in a well established model of neuronal cultures the neuroprotective effects of blocking these mechanisms, either singularly or by combining multiple enzyme inhibition and/or ROS scavenging. In vitro cultures of cerebellar granule cells exposed to a toxic concentration of glutamate (100 microM for 15 min in the absence of Mg2+) combined with several pharmacological treatments. Inhibition of nitric oxide synthase (NOS) and phospholipase A2 (PLA2) were effective in decreasing cell death and the combined treatments showed some degree of additivity. By contrast, inhibition of xanthine oxidase (XO) with allopurinol was uneffective. Antioxidants (in particular vitamin e or vitamin E analogs). protected neurons up to more than 50%. A synergistic effect was demonstrated by the combination of vitamin E and C. On the other hand, antioxidants did not increase the protection granted by enzyme inhibitors, suggesting that they act downstream to NOS and PLA2. In conclusion, NOS and PLA2 activated by Ca2+ influx give rise to reactive oxygen species whose deleterious action can be counteracted either by inhibiting these enzymes or by scavenging the excess of free radicals produced by them. Finally, a moderate protection was obtained by blocking protein synthesis with cycloheximide, suggesting a partial contribution of apoptotic mechanisms to the excitotoxic cell death.
Collapse
Affiliation(s)
- E Ciani
- Department of Biology, University of Bologna, Italy
| | | | | | | | | | | |
Collapse
|
42
|
Abstract
Several possible mechanisms for cysteine toxicity on rat cerebellar granule cells were studied and compared with the excitotoxic effect of glutamate. It was shown that the excitotoxic potency of both cysteine and glutamate increased in the presence of elevated concentrations of bicarbonate or increased pH. Pharmacological studies showed that the cysteine toxicity was specifically coupled to the NMDA receptor, whereas the glutamate toxicity was mediated to a smaller extent also by non-NMDA receptors. Treatment of cerebellar granule cells with cysteine led to an increased extracellular level of glutamate. In addition, cysteine sensitized NMDA receptors by reducing disulfide bonds in the receptor to sulfhydryl groups. A mechanism for cysteine excitotoxicity may therefore be formation of cysteine-sensitized NMDA receptors that are stimulated either by cysteine and/or by endogenous glutamate. This mechanism may also be important for the effects observed during regulated physiological release of cysteine.
Collapse
Affiliation(s)
- G A Mathisen
- Norwegian Defence Research Establishment, Division for Environmental Toxicology, Kjeller, Norway
| | | | | |
Collapse
|
43
|
Abstract
Microdialysis in neostriatum of anaesthetized rats was performed to study effects on amino acid efflux of the glutamate uptake-inhibitor dihydrokainate (DHK). Both basal and K+-evoked (100 mM) efflux of glutamate increased in the presence of DHK. The increase in the basal glutamate efflux occurred at lower DHK concentrations than during K+-depolarization (when the extracellular glutamate concentration was several-fold higher), confirming that DHK is a competitive inhibitor. The increase in basal efflux caused by DHK did not exhibit Ca(2+)-dependency, whereas 50% of the increase in glutamate efflux during K+-depolarization was Ca(2+)-dependent. The Ca(2+)-dependent efflux is related to transmitter release, whereas the Ca(2+)-independent efflux is probably due to metabolic events and/or transport of DHK into cells in exchange for glutamate. Taurine efflux in response to DHK increased both during basal conditions and K+-depolarization, probably secondary to the increase in glutamate concentration, whereas aspartate, GABA, glutamine and alanine effluxes did not change.
Collapse
Affiliation(s)
- A B Fallgren
- Norwegian Defence Research Establishment, Division for Environmental Toxicology, Kjeller, Norway
| | | |
Collapse
|
44
|
Aasmundstad TA, Mørland J, Paulsen RE. Distribution of morphine 6-glucuronide and morphine across the blood-brain barrier in awake, freely moving rats investigated by in vivo microdialysis sampling. J Pharmacol Exp Ther 1995; 275:435-41. [PMID: 7562582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Microdialysis was used to sample morphine 6-glucuronide (M6G) and morphine in striatal extracellular fluid after systemic administration in awake, freely moving rats. Morphine or M6G (25-67 mumol/kg) was given subcutaneously, and blood and striatal dialysate were sampled repeatedly during 120 min. Blood samples were obtained by indwelling catheters in the inferior vena cava. Opiates in serum or brain dialysate were analyzed with high-performance liquid chromatography. The functional intactness of the blood-brain barrier was verified by the use of sodium technetate (Na99mTcO4). The fractional penetration into the brain of morphine and M6G was approximately 350- and 90-fold higher than that of Na99mTcO4, respectively, with a relative difference in the transfer of morphine and M6G of about 4. No hydrolysis of M6G to morphine was detected. Striatal dialysate-to-serum ratios of M6G did not differ after 25 or 67 mumol/kg. Serum AUC0-120 min was 10 times higher for M6G than for morphine. This reflects both a smaller volume of distribution (Vd) for M6G and a decreased rate of elimination compared with morphine. The median t1/2 from serum was 36 and 32 min for morphine and M6G, respectively. The striatal dialysate AUC0-120 min of M6G was 2.9 times greater than that of morphine after an equimolar subcutaneous dose. Dialysate tmax was delayed approximately 40 min relatie to serum tmax for both drugs, and the median t1/2 from the dialysate was 82 and 48 min for M6G and morphine, respectively. These results represent direct evidence for the penetration of M6G into the brain after systemic administration to living rats.
Collapse
|
45
|
Abstract
NGFI-B is an immediate early gene and orphan member of the nuclear receptor superfamily. It is induced in several tissues, including brain, and in cultured cerebellar granule cells in response to different stimuli. Since both the induction of its mRNA as well as the level and function of its gene product are under the control of the inducing stimulus, we wanted to study the final outcome of the stimulus, i.e., transcriptional activity, by means of a specific, artificial reporter gene in cultured CNS cells. Cultured cerebellar granule cells and astrocytes were transfected with an NGFI-B responsive reporter gene to study the role of NGFI-B as a transcriptional activator after stimulation of the protein kinase A and C pathways. In both cell types, stimulation of either protein kinase A or C with forskolin (10 microM) or phorbol 12-myristate 13-acetate (0.1 microM), respectively, gave up to fivefold induction of the reporter gene. In the granule cells a combined treatment gave a strong synergistic induction of the reporter gene. The astrocytes showed only weak synergy, indicating cell-specific regulation of the target gene by the two kinases.
Collapse
Affiliation(s)
- E Ciani
- Division for Environmental Toxicology, Norwegian Defence Research Establishment, Kjeller, Norway
| | | |
Collapse
|
46
|
Affiliation(s)
- F Fonnum
- Norwegian Defence Research Establishment, Division for Environmental Toxicology, Kjeller
| | | | | | | | | |
Collapse
|
47
|
Paulsen RE, Raulli R, Grayson DR, Wroblewski JT. Acute and long-term inhibition of agonist-stimulated phosphoinositide hydrolysis by pulse treatment of cerebellar granule cells with TPA. Mol Chem Neuropathol 1994; 22:67-79. [PMID: 7916769 DOI: 10.1007/bf03160095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Acute pretreatment (30 min) of primary cultures of cerebellar granule cells with TPA (10 nM) resulted in a decrease in carbachol-and glutamate-stimulated phosphoinositide hydrolysis, but not in basal levels of PI hydrolysis. To investigate the mechanism of TPA action, phospholipase C was assayed in membranes prepared from cerebellar granule cells acutely treated with TPA. TPA had no effect on basal, GTP gamma S-, NaF-, and calcium-stimulated phospholipase C when compared with membranes prepared from vehicle-treated cells. The effects of pulsing with TPA (30-min pulse, 10 nM) on agonist-stimulated PI hydrolysis were studied 1, 3, and 5 or 6 d after TPA treatment. TPA treatment results in a statistically significant decrease in glutamate-stimulated PI hydrolysis, and a slight reduction of carbachol-stimulated PI hydrolysis when compared to temporally matched controls. Measurements in membranes prepared from TPA-treated vs control cells 1, 3, and 5 d after treatment showed that calcium- and NaF-stimulated phospholipase C activity was significantly decreased at all days tested, whereas GTP gamma S-stimulated phospholipase C activity was significantly decreased only at d 3. These data demonstrate differences in the acute vs long-term effects of TPA treatment on agonist-stimulated PH hydrolysis, and suggest that the acute effects may be mediated at the level of the receptor, whereas long-term effects of TPA on PI hydrolysis may be mediated by deficits in effector function.
Collapse
Affiliation(s)
- R E Paulsen
- Fidia-Georgetown Institute for the Neurosciences, Georgetown University School of Medicine, Washington, DC 20007
| | | | | | | |
Collapse
|
48
|
Berg-Johnsen J, Paulsen RE, Fonnum F, Langmoen IA. Changes in evoked potentials and amino acid content during fluorocitrate action studied in rat hippocampal cortex. Exp Brain Res 1993; 96:241-6. [PMID: 7903642 DOI: 10.1007/bf00227104] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Fluorocitrate inhibits the glial tricarboxylic acid cycle and thereby the synthesis of glutamine, which is the main precursor for transmitter glutamate. We investigated the possibility that there is a functional correlate to fluorocitrate action by recording evoked field potentials in rat hippocampal slices. The excitatory postsynaptic potential (field-EPSP) was markedly depressed after 7-8 h of fluorocitrate action. The population spike was also reduced, but a major part of the reduction may be the result of weaker synaptic activation rather than reduced excitability of the postsynaptic cells. The activity of thin unmyelinated fibres was only slightly affected. Preceding the changes in the field-EPSP there was a decrease in the glutamine content in the fluorocitrate treated slices relative to controls. Only a small decrease in tissue glutamate was seen concomitantly with the synaptic failure, probably because the transmitter pool of glutamate in those fibres stimulated makes little contribution to the total tissue glutamate.
Collapse
Affiliation(s)
- J Berg-Johnsen
- Institute for Surgical Research, National Hospital, Oslo, Norway
| | | | | | | |
Collapse
|
49
|
Bakkelund AH, Fonnum F, Paulsen RE. Evidence using in vivo microdialysis that aminotransferase activities are important in the regulation of the pools of transmitter amino acids. Neurochem Res 1993; 18:411-5. [PMID: 8097292 DOI: 10.1007/bf00967244] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The effect of aminooxyacetic acid (AOAA), an inhibitor of pyridoxal phosphate-dependent enzymes (including the aminotransferases), on the K(+)-evoked release of amino acids was studied during microdialysis of neostriatum in anesthetized rats. K(+)-evoked (100 mM) release of aspartate, glutamate, and GABA was inhibited by 74%, 70%, and 63%, respectively, by 20 mM Mg2+ and are therefore reflecting release from the transmitter pools of these amino acids. Treatment with AOAA decreased the K(+)-evoked release of aspartate, glutamate, and GABA instantly, with a delayed decrease in the efflux of glutamine and alanine, arguing that the synthesis of transmitter amino acids in particular is sensitive to the activity of pyridoxal phosphate-dependent enzymes. Interestingly, GABA release increased severalfold following the initial decrease, probably reflecting inhibition by AOAA on GABA aminotransferase, the enzyme most sensitive to inhibition by AOAA, and responsible for enzymatic inactivation of transmitter GABA.
Collapse
Affiliation(s)
- A H Bakkelund
- Division for Environmental Toxicology, NDRE, Kjeller, Norway
| | | | | |
Collapse
|
50
|
Myhrer T, Paulsen RE. Memory dysfunction following disruption of glutamergic systems in the temporal region of the rat: effects of agonistic amino acids. Brain Res 1992; 599:345-52. [PMID: 1291038 DOI: 10.1016/0006-8993(92)90411-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
It has previously been shown that disruptions of fiber connections between the temporal cortex (TC) and the lateral entorhinal cortex (LEC) in rats result in severely impaired retention of a simultaneous brightness discrimination task. This memory impairment is accompanied by reduced high affinity D-aspartate uptake in both TC and LEC. The purpose of this study was to investigate whether systemic administration of glutamergic agonists might ameliorate the mnemonic dysfunction seen to follow TC/LEC transections. The results from Experiment 1 show that agonists acting selectively at the NMDA receptors (NMDA and glycine) or the quisqualate receptors (AMPA) produced complete amelioration of the memory deficit. Injection of kainic acid only produced a slight improvement of memory. The results from Experiment 2 show that the positive effects of agonists are probably not attributable to peripheral adrenergic mechanisms, because blockade of sympathetic terminal release did not prevent mitigating effect of glycine. The results are discussed in terms of possible central nervous mechanisms interfered with by the various agonists.
Collapse
Affiliation(s)
- T Myhrer
- Norweigan Defence Research Establishment, Division for Environmental Toxicology, Kjeller
| | | |
Collapse
|