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Meeusen H, Romagnolo A, Holsink SAC, van den Broek TJM, van Helvoort A, Gorter JA, van Vliet EA, Verkuyl JM, Silva JP, Aronica E. A novel hepatocyte ketone production assay to help the selection of nutrients for the ketogenic diet treatment of epilepsy. Sci Rep 2024; 14:11940. [PMID: 38789658 DOI: 10.1038/s41598-024-62723-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 05/21/2024] [Indexed: 05/26/2024] Open
Abstract
The classic ketogenic diet is an effective treatment option for drug-resistant epilepsy, but its high fat content challenges patient compliance. Optimizing liver ketone production guided by a method comparing substrates for their ketogenic potential may help to reduce the fat content of the diet without loss in ketosis induction. Here, we present a liver cell assay measuring the β-hydroxybutyrate (βHB) yield from fatty acid substrates. Even chain albumin-conjugated fatty acids comprising between 4 and 18 carbon atoms showed a sigmoidal concentration-βHB response curve (CRC) whereas acetate and omega-3 PUFAs produced no CRC. While CRCs were not distinguished by their half-maximal effective concentration (EC50), they differed by maximum response, which related inversely to the carbon chain length and was highest for butyrate. The assay also suitably assessed the βHB yield from fatty acid blends detecting shifts in maximum response from exchanging medium chain fatty acids for long chain fatty acids. The assay further detected a dual role for butyrate and hexanoic acid as ketogenic substrate at high concentration and ketogenic enhancer at low concentration, augmenting the βHB yield from oleic acid and a fatty acid blend. The assay also found propionate to inhibit ketogenesis from oleic acid and a fatty acid blend at low physiological concentration. Although the in vitro assay shows promise as a tool to optimize the ketogenic yield of a fat blend, its predictive value requires human validation.
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Affiliation(s)
- Hester Meeusen
- Department of (Neuro)Pathology, Amsterdam UMC, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
- Department of Nutritional Physiology and Functional Nutrients, Medical & Nutrition Science, Danone Nutricia Research, Uppsalalaan 12, 3584CT, Utrecht, The Netherlands
| | - Alessia Romagnolo
- Department of (Neuro)Pathology, Amsterdam UMC, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
- Department of Nutritional Physiology and Functional Nutrients, Medical & Nutrition Science, Danone Nutricia Research, Uppsalalaan 12, 3584CT, Utrecht, The Netherlands
| | - Sophie A C Holsink
- Department of Nutritional Physiology and Functional Nutrients, Medical & Nutrition Science, Danone Nutricia Research, Uppsalalaan 12, 3584CT, Utrecht, The Netherlands
| | - Thijs J M van den Broek
- Department of Nutritional Physiology and Functional Nutrients, Medical & Nutrition Science, Danone Nutricia Research, Uppsalalaan 12, 3584CT, Utrecht, The Netherlands
| | - Ardy van Helvoort
- Department of Nutritional Physiology and Functional Nutrients, Medical & Nutrition Science, Danone Nutricia Research, Uppsalalaan 12, 3584CT, Utrecht, The Netherlands
- Department of Respiratory Medicine, NUTRIM - Research Institute of Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht University, Maastricht, The Netherlands
| | - Jan A Gorter
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
| | - Erwin A van Vliet
- Department of (Neuro)Pathology, Amsterdam UMC, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
| | - J Martin Verkuyl
- Department of Nutritional Physiology and Functional Nutrients, Medical & Nutrition Science, Danone Nutricia Research, Uppsalalaan 12, 3584CT, Utrecht, The Netherlands
| | - Jose P Silva
- Department of Nutritional Physiology and Functional Nutrients, Medical & Nutrition Science, Danone Nutricia Research, Uppsalalaan 12, 3584CT, Utrecht, The Netherlands.
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Amsterdam UMC, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands
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Thau-Zuchman O, Pallier PN, Savelkoul PJM, Kuipers AAM, Verkuyl JM, Michael-Titus AT. High phenylalanine concentrations induce demyelination and microglial activation in mouse cerebellar organotypic slices. Front Neurosci 2022; 16:926023. [PMID: 36248632 PMCID: PMC9559601 DOI: 10.3389/fnins.2022.926023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 09/05/2022] [Indexed: 11/29/2022] Open
Abstract
Phenylketonuria (PKU) is an inborn error of metabolism. Mutations in the enzyme phenylalanine hydroxylase (PAH)-encoding gene lead to a decreased metabolism of the amino acid phenylalanine (Phe). The deficiency in PAH increases Phe levels in blood and brain. Accumulation of Phe can lead to delayed development, psychiatric problems and cognitive impairment. White matter (WM) damage is a neuropathological hallmark of PKU and can be seen even in early detected and treated PKU patients. The mechanisms linking high Phe concentrations to WM abnormalities remain unclear. We tested the effects of high Phe concentrations on myelin in three in vitro models of increasing complexity: two simple cell culture models and one model that preserves local brain tissue architecture, a cerebellar organotypic slice culture prepared from postnatal day (P) 8 CD-1 mice. Various Phe concentrations (0.1–10 mM) and durations of exposure were tested. We found no toxic effect of high Phe in the cell culture models. On the contrary, the treatment promoted the maturation of oligodendrocytes, particularly at the highest, non-physiological Phe concentrations. Exposure of cerebellar organotypic slices to 2.4 mM Phe for 21 days in vitro (DIV), but not 7 or 10 DIV, resulted in a significant decrease in myelin basic protein (MBP), calbindin-stained neurites, and neurites co-stained with MBP. Following exposure to a toxic concentration of Phe, a switch to the control medium for 7 days did not lead to remyelination, while very active remyelination was seen in slices following demyelination with lysolecithin. An enhanced number of microglia, displaying an activated type morphology, was seen after exposure of the slices to 2.4 mM Phe for 10 or 21 DIV. The results suggest that prolonged exposure to high Phe concentrations can induce microglial activation preceding significant disruption of myelin.
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Affiliation(s)
- Orli Thau-Zuchman
- Centre for Neuroscience, Surgery and Trauma, Barts and The London School of Medicine and Dentistry, The Blizard Institute, Queen Mary University of London, London, United Kingdom
| | - Patrick N. Pallier
- Centre for Neuroscience, Surgery and Trauma, Barts and The London School of Medicine and Dentistry, The Blizard Institute, Queen Mary University of London, London, United Kingdom
- *Correspondence: Patrick N. Pallier,
| | | | | | | | - Adina T. Michael-Titus
- Centre for Neuroscience, Surgery and Trauma, Barts and The London School of Medicine and Dentistry, The Blizard Institute, Queen Mary University of London, London, United Kingdom
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Dalile B, Kim C, Challinor A, Geurts L, Gibney ER, Galdos MV, La Fata G, Layé S, Mathers JC, Vauzour D, Verkuyl JM, Thuret S. The EAT-Lancet reference diet and cognitive function across the life course. Lancet Planet Health 2022; 6:e749-e759. [PMID: 36087605 DOI: 10.1016/s2542-5196(22)00123-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 05/02/2022] [Accepted: 05/13/2022] [Indexed: 06/15/2023]
Abstract
The EAT-Lancet Commission devised a sustainable reference diet with the aim of reducing the incidence of non-communicable diseases and mortality globally while improving food system sustainability. The extent to which the reference diet supports cognitive function across the life course, however, has not yet been evaluated. This Review assesses the evidence for diet supporting cognitive function from childhood into old age. A comprehensive but non-exhaustive literature search was done, synthesising studies that investigated the effect of whole foods on cognition in healthy, community-dwelling human participants. We found that the current evidence base is weak with mixed conclusions and multiple methodological caveats, which precludes strong conclusions pertaining to the suitability of dietary recommendations for each food group per age group. Long-term intervention and prospective cohort studies are needed to reduce this knowledge deficit. Revising dietary recommendations with the aim of maintaining an adequate nutrient intake to sustain healthy cognitive function across the life course could be worthwhile. This Review outlines recommendations for future work to help improve the current knowledge deficit regarding dietary intake and cognitive function across the life course and its implications for dietary guidelines such as the EAT-Lancet Commission.
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Affiliation(s)
- Boushra Dalile
- Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium
| | - Curie Kim
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Andy Challinor
- Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds, UK
| | - Lucie Geurts
- International Life Sciences Institute European Branch, Brussels, Belgium
| | - Eileen R Gibney
- Institute of Food Health, School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Marcelo V Galdos
- Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds, UK
| | - Giorgio La Fata
- Health Nutrition and Care Innovation, Global Research and Development Center, DSM Nutritional Products, Kaiseraugst, Switzerland
| | - Sophie Layé
- Nutrition et Neurobiologie Intégrée, INRA Bordeaux University, Bordeaux, France
| | - John C Mathers
- Human Nutrition Research Centre, Population Health Sciences Institute, Newcastle University, Newcastle Upon Tyne, UK
| | - David Vauzour
- Norwich Medical School, Biomedical Research Centre, University of East Anglia, Norwich, UK
| | - J Martin Verkuyl
- Danone Nutricia Research, Nutricia Advanced Medical Nutrition, Utrecht, Netherlands
| | - Sandrine Thuret
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.
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Thau-Zuchman O, Svendsen L, Dyall SC, Paredes-Esquivel U, Rhodes M, Priestley JV, Feichtinger RG, Kofler B, Lotstra S, Verkuyl JM, Hageman RJ, Broersen LM, van Wijk N, Silva JP, Tremoleda JL, Michael-Titus AT. A new ketogenic formulation improves functional outcome and reduces tissue loss following traumatic brain injury in adult mice. Theranostics 2021; 11:346-360. [PMID: 33391479 PMCID: PMC7681084 DOI: 10.7150/thno.48995] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 09/25/2020] [Indexed: 12/14/2022] Open
Abstract
Rationale: Traumatic brain injury (TBI) leads to neurological impairment, with no satisfactory treatments available. Classical ketogenic diets (KD), which reduce reliance on carbohydrates and provide ketones as fuel, have neuroprotective potential, but their high fat content reduces compliance, and experimental evidence suggests they protect juvenile brain against TBI, but not adult brain, which would strongly limit their applicability in TBI. Methods: We designed a new-KD with a fat to carbohydrate plus protein ratio of 2:1, containing medium chain triglycerides (MCT), docosahexaenoic acid (DHA), low glycaemic index carbohydrates, fibres and the ketogenic amino acid leucine, and evaluated its neuroprotective potential in adult TBI. Adult male C57BL6 mice were injured by controlled cortical impact (CCI) and assessed for 70 days, during which they received a control diet or the new-KD. Results: The new-KD, that markedly increased plasma Beta-hydroxybutyrate (β-HB), significantly attenuated sensorimotor deficits and corrected spatial memory deficit. The lesion size, perilesional inflammation and oxidation were markedly reduced. Oligodendrocyte loss appeared to be significantly reduced. TBI activated the mTOR pathway and the new-KD enhanced this increase and increased histone acetylation and methylation. Conclusion: The behavioural improvement and tissue protection provide proof of principle that this new formulation has therapeutic potential in adult TBI.
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Kurtys E, Casteels C, Real CC, Eisel ULM, Verkuyl JM, Broersen LM, Klein HC, Dierckx RAJO, Doorduin J, de Vries EFJ. Therapeutic effects of dietary intervention on neuroinflammation and brain metabolism in a rat model of photothrombotic stroke. CNS Neurosci Ther 2018; 25:36-46. [PMID: 29804326 PMCID: PMC6436598 DOI: 10.1111/cns.12976] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 04/23/2018] [Accepted: 04/23/2018] [Indexed: 12/18/2022] Open
Abstract
INTRODUCTION A possible target for stroke management is modulation of neuroinflammation. Evidence suggests that food components may exert anti-inflammatory properties and thus may reduce stroke-induced brain damage. AIM To investigate the efficacy of a diet, containing anti-inflammatory ingredients, as treatment for focal ischemic brain damage induced by photothrombotic stroke in the somatosensory cortex of rats. RESULTS Brain lesions were surrounded by strong astrogliosis on both day 7 and day 21 after stroke and were accompanied by a trend toward globally decreased glucose metabolism on day 7. The investigational diet applied 2 weeks before the ischemia did not affect astrocyte activation on day 7, but reduced it at day 21. The investigational diet applied immediately after the ischemia, increased astrocyte activation on day 7 and completely reversed this effect on day 21. Moreover, postischemic intervention increased glucose metabolism in somatosensory cortex ipsilateral to the lesion on day 7. CONCLUSION This study reveals potentially beneficial effects of a diet containing elevated amounts of anti-inflammatory nutrients on the recovery from ischemic brain damage. Therefore, dietary intervention can be considered as an adjuvant therapy for recovery from this brain pathology.
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Affiliation(s)
- Ewelina Kurtys
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Cindy Casteels
- Molecular Small Animal Imaging Center, Catholic University Leuven, Leuven, Belgium
| | - Caroline C Real
- Laboratory of Cellular Neurobiology, Department of Physiology and Biophysics, University of São Paulo, São Paulo, Brazil
| | - Ulrich L M Eisel
- Department of Molecular Neurobiology, University of Groningen, GELIFES, Groningen, The Netherlands
| | | | | | - Hans C Klein
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Department of Psychiatry, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Janine Doorduin
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Erik F J de Vries
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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Affiliation(s)
- Ewelina Kurtys
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, RB Groningen, The Netherlands
| | - Ulrich L M Eisel
- Department of Molecular Neurobiology, GELIFES, University of Groningen, Groningen, The Netherlands
| | | | | | | | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, RB Groningen, The Netherlands
| | - Erik F J de Vries
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, RB Groningen, The Netherlands
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van Deijk ALF, Broersen LM, Verkuyl JM, Smit AB, Verheijen MHG. High Content Analysis of Hippocampal Neuron-Astrocyte Co-cultures Shows a Positive Effect of Fortasyn Connect on Neuronal Survival and Postsynaptic Maturation. Front Neurosci 2017; 11:440. [PMID: 28824363 PMCID: PMC5543085 DOI: 10.3389/fnins.2017.00440] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 07/19/2017] [Indexed: 01/01/2023] Open
Abstract
Neuronal and synaptic membranes are composed of a phospholipid bilayer. Supplementation with dietary precursors for phospholipid synthesis –docosahexaenoic acid (DHA), uridine and choline– has been shown to increase neurite outgrowth and synaptogenesis both in vivo and in vitro. A role for multi-nutrient intervention with specific precursors and cofactors has recently emerged in early Alzheimer's disease, which is characterized by decreased synapse numbers in the hippocampus. Moreover, the medical food Souvenaid, containing the specific nutrient combination Fortasyn Connect (FC), improves memory performance in early Alzheimer's disease patients, possibly via maintaining brain connectivity. This suggests an effect of FC on synapses, but the underlying cellular mechanism is not fully understood. Therefore, we investigated the effect of FC (consisting of DHA, eicosapentaenoic acid (EPA), uridine, choline, phospholipids, folic acid, vitamins B12, B6, C and E, and selenium), on synaptogenesis by supplementing it to primary neuron-astrocyte co-cultures, a cellular model that mimics metabolic dependencies in the brain. We measured neuronal developmental processes using high content screening in an automated manner, including neuronal survival, neurite morphology, as well as the formation and maturation of synapses. Here, we show that FC supplementation resulted in increased numbers of neurons without affecting astrocyte number. Furthermore, FC increased postsynaptic PSD95 levels in both immature and mature synapses. These findings suggest that supplementation with FC to neuron-astrocyte co-cultures increased both neuronal survival and the maturation of postsynaptic terminals, which might aid the functional interpretation of FC-based intervention strategies in neurological diseases characterized by neuronal loss and impaired synaptic functioning.
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Affiliation(s)
- Anne-Lieke F van Deijk
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, VU University AmsterdamAmsterdam, Netherlands
| | - Laus M Broersen
- Advanced Medical Nutrition, Nutricia ResearchUtrecht, Netherlands
| | - J Martin Verkuyl
- Advanced Medical Nutrition, Nutricia ResearchUtrecht, Netherlands
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, VU University AmsterdamAmsterdam, Netherlands
| | - Mark H G Verheijen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, VU University AmsterdamAmsterdam, Netherlands
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Kurtys E, Eisel ULM, Verkuyl JM, Broersen LM, Dierckx RAJO, de Vries EFJ. The combination of vitamins and omega-3 fatty acids has an enhanced anti-inflammatory effect on microglia. Neurochem Int 2016; 99:206-214. [PMID: 27465516 DOI: 10.1016/j.neuint.2016.07.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [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: 04/26/2016] [Revised: 07/01/2016] [Accepted: 07/18/2016] [Indexed: 01/27/2023]
Abstract
Neuroinflammation is a common phenomenon in the pathology of many brain diseases. In this paper we explore whether selected vitamins and fatty acids known to modulate inflammation exert an effect on microglia, the key cell type involved in neuroinflammation. Previously these nutrients have been shown to exert anti-inflammatory properties acting on specific inflammatory pathways. We hypothesized that combining nutrients acting on converging anti-inflammatory pathways may lead to enhanced anti-inflammatory properties as compared to the action of a single nutrient. In this study, we investigated the anti-inflammatory effect of combinations of nutrients based on the ability to inhibit the LPS-induced release of nitric oxide and interleukin-6 from BV-2 cells. Results show that omega-3 fatty acids, vitamins A and D can individually reduce the LPS-induced secretion of the pro-inflammatory cytokines by BV-2 cells. Moreover, we show that vitamins A, D and omega-3 fatty acids (docosahexaenoic and eicosapentaenoic) at concentrations where they individually had little effect, significantly reduced the secretion of the inflammatory mediator, nitric oxide, when they were combined. The conclusion of this study is that combining different nutrients acting on convergent anti-inflammatory pathways may result in an increased anti-inflammatory efficacy.
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Affiliation(s)
- E Kurtys
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands
| | - U L M Eisel
- Department of Molecular Neurobiology, Center for Life Sciences, University of Groningen, Groningen, The Netherlands
| | - J M Verkuyl
- Nutricia Research, Uppsalalaan 12, 3584 CT Utrecht, The Netherlands
| | - L M Broersen
- Nutricia Research, Uppsalalaan 12, 3584 CT Utrecht, The Netherlands
| | - R A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands
| | - E F J de Vries
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands.
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Carson C, Raman P, Tullai J, Xu L, Henault M, Thomas E, Yeola S, Lao J, McPate M, Verkuyl JM, Marsh G, Sarber J, Amaral A, Bailey S, Lubicka D, Pham H, Miranda N, Ding J, Tang HM, Ju H, Tranter P, Ji N, Krastel P, Jain RK, Schumacher AM, Loureiro JJ, George E, Berellini G, Ross NT, Bushell SM, Erdemli G, Solomon JM. Englerin A Agonizes the TRPC4/C5 Cation Channels to Inhibit Tumor Cell Line Proliferation. PLoS One 2015; 10:e0127498. [PMID: 26098886 PMCID: PMC4476799 DOI: 10.1371/journal.pone.0127498] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 04/14/2015] [Indexed: 01/19/2023] Open
Abstract
Englerin A is a structurally unique natural product reported to selectively inhibit growth of renal cell carcinoma cell lines. A large scale phenotypic cell profiling experiment (CLiP) of englerin A on ¬over 500 well characterized cancer cell lines showed that englerin A inhibits growth of a subset of tumor cell lines from many lineages, not just renal cell carcinomas. Expression of the TRPC4 cation channel was the cell line feature that best correlated with sensitivity to englerin A, suggesting the hypothesis that TRPC4 is the efficacy target for englerin A. Genetic experiments demonstrate that TRPC4 expression is both necessary and sufficient for englerin A induced growth inhibition. Englerin A induces calcium influx and membrane depolarization in cells expressing high levels of TRPC4 or its close ortholog TRPC5. Electrophysiology experiments confirmed that englerin A is a TRPC4 agonist. Both the englerin A induced current and the englerin A induced growth inhibition can be blocked by the TRPC4/C5 inhibitor ML204. These experiments confirm that activation of TRPC4/C5 channels inhibits tumor cell line proliferation and confirms the TRPC4 target hypothesis generated by the cell line profiling. In selectivity assays englerin A weakly inhibits TRPA1, TRPV3/V4, and TRPM8 which suggests that englerin A may bind a common feature of TRP ion channels. In vivo experiments show that englerin A is lethal in rodents near doses needed to activate the TRPC4 channel. This toxicity suggests that englerin A itself is probably unsuitable for further drug development. However, since englerin A can be synthesized in the laboratory, it may be a useful chemical starting point to identify novel modulators of other TRP family channels.
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Affiliation(s)
- Cheryl Carson
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Pichai Raman
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Jennifer Tullai
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Lei Xu
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Martin Henault
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Emily Thomas
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Sarita Yeola
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Jianmin Lao
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Mark McPate
- Novartis Institutes for Biomedical Research, Horsham, United Kingdom
| | - J. Martin Verkuyl
- Novartis Institutes for Biomedical Research, Horsham, United Kingdom
| | - George Marsh
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Jason Sarber
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Adam Amaral
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Scott Bailey
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Danuta Lubicka
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Helen Pham
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Nicolette Miranda
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Jian Ding
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Hai-Ming Tang
- Novartis Institutes for Biomedical Research, East Hanover, New Jersey, United States of America
| | - Haisong Ju
- Novartis Institutes for Biomedical Research, East Hanover, New Jersey, United States of America
| | - Pamela Tranter
- Novartis Institutes for Biomedical Research, Horsham, United Kingdom
| | - Nan Ji
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Philipp Krastel
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Rishi K. Jain
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Andrew M. Schumacher
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Joseph J. Loureiro
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Elizabeth George
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Giuliano Berellini
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Nathan T. Ross
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Simon M. Bushell
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Gül Erdemli
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Jonathan M. Solomon
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
- * E-mail:
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Abstract
The capsaicin receptor, TRPV1, has been one of the most extensively studied molecules in sensory research. Its contribution to the sensation of pain in numerous pre-clinical inflammatory and neuropathic paradigms has been well-established and expression analysis suggests a potential role clinically in pain and bladder conditions. The field has now reached an exciting point in time with the development of a number of high quality TRPV1 antagonist drug candidates and the release of clinical data. What has become apparent from this work is that inhibition of TRPV1 function brings with it the potential liabilities of increased body temperature and altered thermal perception. However, there is cause for optimism because it appears that not all antagonists have the same properties and compounds can be identified that lack significant on-target side-effects whilst retaining efficacy, at least pre-clinically. What is perhaps now more critical to address is the question of how effective the analgesia provided by a TRPV1 antagonist will be. Although tantalizing clinical data showing effects on experimentally-induced pain or pain following molar extraction have been reported, no clear efficacy in a chronic pain condition has yet been demonstrated making it difficult to perform an accurate risk-benefit analysis for TRPV1 antagonists. Here we provide an overview of some of the most advanced clinical candidates and discuss the approaches being taken to avoid the now well established on-target effects of TRPV1 antagonists.
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Affiliation(s)
- Mark S. Nash
- Novartis Institutes for Biomedical Research Forum 1, Novartis Campus CH - 4056 Basel Switzerland
| | - J. Martin Verkuyl
- Novartis Institutes for Biomedical Research Wimblehurst Road Horsham, West Sussex RH12 5AB UK
| | - Gurdip Bhalay
- Novartis Institutes for Biomedical Research Wimblehurst Road Horsham, West Sussex RH12 5AB UK
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Rooney L, Vidal A, D’Souza AM, Devereux N, Masick B, Boissel V, West R, Head V, Stringer R, Lao J, Petrus MJ, Patapoutian A, Nash M, Stoakley N, Panesar M, Verkuyl JM, Schumacher AM, Petrassi HM, Tully DC. Discovery, Optimization, and Biological Evaluation of 5-(2-(Trifluoromethyl)phenyl)indazoles as a Novel Class of Transient Receptor Potential A1 (TRPA1) Antagonists. J Med Chem 2014; 57:5129-40. [DOI: 10.1021/jm401986p] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lisa Rooney
- Novartis Institutes for Biomedical Research, Wimblehurst Road, Horsham RH12 5AB, United Kingdom
| | - Agnès Vidal
- Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, California 92121, United States
| | - Anne-Marie D’Souza
- Novartis Institutes for Biomedical Research, Wimblehurst Road, Horsham RH12 5AB, United Kingdom
| | - Nick Devereux
- Novartis Institutes for Biomedical Research, Wimblehurst Road, Horsham RH12 5AB, United Kingdom
| | - Brian Masick
- Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, California 92121, United States
| | - Valerie Boissel
- Novartis Institutes for Biomedical Research, Wimblehurst Road, Horsham RH12 5AB, United Kingdom
| | - Ryan West
- Novartis Institutes for Biomedical Research, Wimblehurst Road, Horsham RH12 5AB, United Kingdom
| | - Victoria Head
- Novartis Institutes for Biomedical Research, Wimblehurst Road, Horsham RH12 5AB, United Kingdom
| | - Rowan Stringer
- Novartis Institutes for Biomedical Research, Wimblehurst Road, Horsham RH12 5AB, United Kingdom
| | - Jianmin Lao
- Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, California 92121, United States
| | - Matt J. Petrus
- Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, California 92121, United States
| | - Ardem Patapoutian
- Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, California 92121, United States
| | - Mark Nash
- Novartis Institutes for Biomedical Research, Wimblehurst Road, Horsham RH12 5AB, United Kingdom
| | - Natalie Stoakley
- Novartis Institutes for Biomedical Research, Wimblehurst Road, Horsham RH12 5AB, United Kingdom
| | - Moh Panesar
- Novartis Institutes for Biomedical Research, Wimblehurst Road, Horsham RH12 5AB, United Kingdom
| | - J. Martin Verkuyl
- Novartis Institutes for Biomedical Research, Wimblehurst Road, Horsham RH12 5AB, United Kingdom
| | - Andrew M. Schumacher
- Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, California 92121, United States
| | - H. Michael Petrassi
- Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, California 92121, United States
| | - David C. Tully
- Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, California 92121, United States
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12
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McPate M, Bhalay G, Beckett M, Fairbrother S, Gosling M, Groot-Kormelink PJ, Lane R, Kent T, Van Diepen MT, Tranter P, Verkuyl JM. The Development of Automated Patch Clamp Assays for Canonical Transient Receptor Potential Channels TRPC3, 6, and 7. Assay Drug Dev Technol 2014; 12:282-92. [PMID: 24906109 DOI: 10.1089/adt.2014.574] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Mark McPate
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - Gurdip Bhalay
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - Martin Beckett
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - Sian Fairbrother
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - Martin Gosling
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - Paul J. Groot-Kormelink
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - Rebecca Lane
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - Toby Kent
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - Michiel T. Van Diepen
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - Pamela Tranter
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - J. Martin Verkuyl
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
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13
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Abbott-Banner K, Poll C, Verkuyl JM. Targeting TRP channels in airway disorders. Curr Top Med Chem 2014; 13:310-21. [PMID: 23506455 DOI: 10.2174/1568026611313030008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 01/07/2013] [Indexed: 11/22/2022]
Abstract
Novel effective therapeutic agents are actively sought for the treatment of a broad spectrum of respiratory diseases which collectively significantly impact on mortality, morbidity and quality of life of hundreds of millions of people world-wide. These include asthma, allergic rhinitis, chronic obstructive pulmonary disease, cough, idiopathic pulmonary fibrosis, pulmonary arterial hypertension, cystic fibrosis and acute lung injury. TRP channels are broadly distributed throughout the respiratory tract and play an important physiological role in sensing and subsequently responding to a wide variety of stimuli, for example temperature, osmolarity and oxidant stress. In the context of respiratory disease however TRP channel function may be altered, eg: under conditions of oxidative stress, inflammation, hypoxia and mechanical stress. In addition there is evidence that the expression/activity of TRP channels can be affected in the disease setting. Modulators of TRP channel function are therefore under investigation for a range of diseases including disorders of the respiratory system. Several excellent review articles have discussed in detail evidence that modulation of specific TRP channels may be of benefit in specific respiratory diseases. In this article we have taken the approach of reviewing evidence that modulation of TRP channel function may be able to affect common and over-lapping characteristic features of respiratory diseases, for example bronchoconstriction, airways hyper-responsiveness, cough, airways inflammation, mucus hyper-secretion, exacerbations, lung injury, hypoxia and airways re-modelling. The therapeutic potential of TRP channel modulators, the status of these agents in the clinic along with the challenges posed in this rapidly advancing field are also discussed in this review.
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14
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McPate MJ, Bhalay G, Fairbrother S, Gosling M, Groot-Kormelink PJ, Lane R, Kent T, Van Diepen M, Verkuyl JM, Tranter P. Development of TRPC Assays on Automated Electrophysiology Platforms. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.4147] [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: 10/23/2022] Open
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15
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Zeng F, Wind N, McClenaghan C, Verkuyl JM, Watson RP, Nash MS. GPR39 is coupled to TMEM16A in intestinal fibroblast-like cells. PLoS One 2012; 7:e47686. [PMID: 23133519 PMCID: PMC3485058 DOI: 10.1371/journal.pone.0047686] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [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: 05/09/2012] [Accepted: 09/18/2012] [Indexed: 12/04/2022] Open
Abstract
GPR39 is a GPCR implicated as a regulator of gastrointestinal motility, although the mechanism remains elusive. Here, we report that GPR39 is expressed by a specific cell population cultured from mouse small intestine muscle layers, which was subsequently identified as fibroblast-like cells (FLCs) that have recently been shown to modulate gut motility. Application of the GPR39 agonist, Zn2+, induced large currents and membrane depolarization in FLCs cultured from wild-type mice, but not Gpr39−/− mice. This Zn2+-induced current could be suppressed by application of a TMEM16A antagonist, CaCCinh-A01, or by silencing Tmem16a expression. These data suggest that GPR39 might modulate gut motility via regulating TMEM16A function in FLCs.
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Affiliation(s)
- Fanning Zeng
- Gastrointestinal Disease Area, Novartis Horsham Research Centre, Horsham, United Kingdom.
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16
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Abstract
Dendritic spines are small protrusions present postsynaptically at approximately 90% of excitatory synapses in the brain. Spines undergo rapid spontaneous changes in shape that are thought to be important for alterations in synaptic connectivity underlying learning and memory. Visualization of these dynamic changes in spine morphology are especially challenging because of the small size of spines (approximately 1 microm). Here we describe a microscope system, based on a spinning-disk confocal microscope, suitable for imaging mature dendritic spines in brain slice preparations, with a time resolution of seconds. We discuss two commonly used in vitro brain slice preparations and methods for transfecting them. Preparation and transfection require approximately 1 d, after which slices must be cultured for at least 21 d to obtain spines of mature morphology. We also describe imaging and computer analysis routines for studying spine motility. These procedures require in the order of 2 to 4 h.
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Affiliation(s)
- J Martin Verkuyl
- Friedrich Miescher Institute, Maulbeerstrasse 66, 4058 Basel, Switzerland
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17
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Birbach A, Verkuyl JM, Matus A. Reversible, activity-dependent targeting of profilin to neuronal nuclei. Exp Cell Res 2006; 312:2279-87. [PMID: 16716297 DOI: 10.1016/j.yexcr.2006.03.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [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: 12/10/2005] [Revised: 03/17/2006] [Accepted: 03/23/2006] [Indexed: 01/28/2023]
Abstract
The actin cytoskeleton in pyramidal neurons plays a major role in activity-dependent processes underlying neuronal plasticity. The small actin-binding protein profilin shows NMDA receptor-dependent accumulation in dendritic spines, which is correlated with suppression of actin dynamics and long-term stabilization of synaptic morphology. Here we show that following NMDA receptor activation profilin also accumulates in the nucleus of hippocampal neurons via a process involving rearrangement of the actin cytoskeleton. This simultaneous targeting to dendritic spines and the cell nucleus suggests a novel mechanism of neuronal plasticity in which profilin both tags activated synapses and influences nuclear events.
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Affiliation(s)
- Andreas Birbach
- Friedrich Miescher Institute, Maulbeerstrasse 66, 4058 Basel, Switzerland.
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18
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Abstract
Parvocellular neurons in the hypothalamic paraventricular nucleus receive hormonal inputs mediated by corticosterone as well as neuronal inputs, prominent among which is a GABAergic inhibitory projection. In the present study we examined the functional properties of this GABAergic innervation when corticosteroid levels fluctuate. Frequency, amplitude and kinetic properties of miniature inhibitory postsynaptic potentials (mIPSCs), mediated by gamma amino butyric acid (GABA) were studied with whole cell recording in parvocellular neurons. Injection of a high dose of corticosterone in vivo suppressed the frequency but did not change the amplitude and kinetic properties of mIPSCs recorded 1-5 h later in vitro. Similar effects were observed after restraint stress. The corticosteroid actions do not require involvement of extrahypothalamic brain regions, because in vitro administration of 100 nM corticosterone (20 min) directly to a hypothalamic slice also suppressed the frequency of mIPSCs recorded several hours later. Corticosterone administration to hypothalamic slices from restraint rats did not result in stronger reduction of mIPSC frequency than either treatment alone, pointing to a common underlying mechanism. Paired pulse response inhibition was reduced by corticosterone, suggesting that the hormone decreases the release probability of GABA-containing vesicles. Unlike neurosteroids, corticosterone induced no rapid effects on mIPSC properties. These results indicate that increases in glucocorticoid level due to stress can slowly but persistently inhibit the GABAergic tone on parvocellular hypothalamic neurons via a hitherto unknown local mechanism independent of limbic projections.
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Affiliation(s)
- J Martin Verkuyl
- Swammerdam Institute for Life Sciences, section Neurobiology, University of Amsterdam, Kruislaan 320, 1098 SM Amsterdam, The Netherlands
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19
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Verkuyl JM, Hemby SE, Joëls M. Chronic stress attenuates GABAergic inhibition and alters gene expression of parvocellular neurons in rat hypothalamus. Eur J Neurosci 2004; 20:1665-73. [PMID: 15355334 DOI: 10.1111/j.1460-9568.2004.03568.x] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Chronic stress causes disinhibition of the hypothalamus-pituitary-adrenal axis. Consequently, the brain is overexposed to glucocorticoids which in humans may precipitate stress-related disorders, e.g. depression. The hypothalamus-pituitary-adrenal activity is strongly regulated by GABAergic input to parvocellular neurons in the hypothalamic paraventricular nucleus. We here report a reduced frequency of miniature inhibitory postsynaptic currents (mIPSCs) in parvocellular neurons of rats exposed to 3 weeks of unpredictable stress. The mIPSC amplitude and kinetic properties were unchanged, pointing to a presynaptic change caused by chronic stress. Because paired-pulse inhibition was unaffected by chronic stress, the number of functional GABAergic synaptic contacts rather than the release probability seems to be reduced after chronic stress. Linearly amplified RNA from postsynaptic cells was hybridized with multiple cDNA clones of interest, including most GABA(A) receptor subunits. In agreement with the electrophysiological observations, relative expression of the prevalent GABA(A)alpha1, alpha3, gamma1 and gamma2 receptor subunits, which largely contribute to the recorded responses, was not altered after chronic stress. However, expression of the extra-synaptic GABA(A)alpha5 subunit, earlier linked to depression in humans, and of the delta receptor subunit were found to be significantly changed. In conclusion, chronic stress leads to presynaptic functional alterations in GABAergic input to the paraventricular nucleus which could contribute to the observed disinhibition of the hypothalamus-pituitary-adrenal axis; additionally other aspects of GABAergic transmission may also be changed due to transcriptional regulation of specific receptor subunits in the parvocellular neurons.
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MESH Headings
- 6-Cyano-7-nitroquinoxaline-2,3-dione/pharmacology
- Animals
- Blotting, Northern/methods
- Body Weight/physiology
- Chronic Disease
- Dose-Response Relationship, Radiation
- Electric Stimulation/methods
- Excitatory Amino Acid Agonists/pharmacology
- Excitatory Amino Acid Antagonists/pharmacology
- Gene Expression/physiology
- Hypothalamus/cytology
- In Vitro Techniques
- Male
- Membrane Potentials/drug effects
- Membrane Potentials/radiation effects
- N-Methylaspartate/pharmacology
- Neural Inhibition/physiology
- Neurons/metabolism
- Organ Size/physiology
- Patch-Clamp Techniques/methods
- RNA, Messenger/biosynthesis
- Rats
- Rats, Wistar
- Receptors, GABA/classification
- Receptors, GABA/genetics
- Receptors, GABA/metabolism
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Stress, Physiological/metabolism
- Stress, Physiological/physiopathology
- Time Factors
- alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid/pharmacology
- gamma-Aminobutyric Acid/metabolism
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Affiliation(s)
- J Martin Verkuyl
- Swammerdam Institute for Life Sciences, Neurobiology section, Kruislaan 320, 1098 SM Amsterdam, The Netherlands
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20
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Abstract
Hyperactivity of the hypothalamo-pituitary-adrenal (HPA) axis is often observed in association with and even prior to the onset of major depression. It is presently unclear (1) which molecular and cellular processes contribute to hyperactivity of parvocellular hypothalamic neurons (key regulators of the HPA system) and (2) how HPA axis hyperactivity can lead to attenuation of central serotonergic transmission, a crucial factor in the onset of clinical symptoms. In an attempt to address these issues in an experimental model we used rats exposed to chronic unpredictable stressors, a paradigm causing prolonged HPA-axis hyperactivity. In the first study spontaneous and evoked GABA-mediated input to parvocellular neurons in the paraventricular hypothalamic nucleus was recorded with the whole cell patch-clamp technique. The frequency, but not other properties, of spontaneous GABA-mediated inhibitory postsynaptic currents was reduced after chronic stress, resulting in a reduced amplitude of the evoked GABA current. This potentially would disinhibit parvocellular neurons, provided that other inputs are unchanged. In the second study, responses of CA1 hippocampal neurons to serotonin were recorded with microelectrodes. It appeared that the membrane hyperpolarization caused by activation of serotonin-1A receptors is attenuated in tissue from chronically stressed rats. However, no apparent changes in expression of the serotonin-1A or corticosteroid receptors were observed. This supports the notion that chronic stress eventually results in attenuation of serotonergic responsiveness by a mechanism not involving transcriptional regulation of the receptor. Follow-up studies will need to examine whether treatment with corticosteroid receptor antagonists can normalize the attenuated transmission after chronic stress.
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Affiliation(s)
- M Joëls
- Swammerdam Institute for Life Sciences, Section Neurobiology, University of Amsterdam, 1098 SM Amsterdam, the Netherlands.
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21
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Joëls M, Velzing E, Nair S, Verkuyl JM, Karst H. Acute stress increases calcium current amplitude in rat hippocampus: temporal changes in physiology and gene expression. Eur J Neurosci 2003; 18:1315-24. [PMID: 12956730 DOI: 10.1046/j.1460-9568.2003.02845.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [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: 12/29/2022]
Abstract
Activation of hippocampal glucocorticoid receptors in vitro increases calcium current amplitude through a process requiring DNA binding of receptor homodimers. We here investigated (i). whether similar increased calcium currents also occur following in vivo glucocorticoid receptor activation due to stress and (ii). if so, whether this can be explained by increased expression of calcium channel subunits. Rats were exposed to a novelty stress; some of the animals were pretreated with a glucocorticoid receptor antagonist. In subsequently prepared hippocampal slices, calcium currents were recorded from identified CA1 pyramidal neurons, after which RNA was collected, linearly amplified and hybridized with cDNA clones. Glucocorticoid receptor activation due to novelty exposure was associated with large total peak calcium currents and high-threshold noninactivating currents. Low-threshold calcium currents were not affected. Large total peak and noninactivating current amplitudes were also seen when animals received a more severe stressor, i.e. additional ether exposure. In the stressed groups, the total peak and high-threshold calcium current gradually increased with time resulting in a significant enhancement at >or=3 h after stress exposure. In the same cells, the summated (relative) RNA expression of various alpha1 calcium channel subunits was only transiently enhanced, prior to the functional changes. These data indicate that in vivo activation of glucocorticoid receptors due to stress gradually increases specific calcium current components. Prior to the functional change, increased expression of calcium channel subunits was observed, suggesting that the enhanced function could be explained by transcriptional regulation of the channels.
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Affiliation(s)
- M Joëls
- Swammerdam Institute for Life Sciences, University of Amsterdam, Kruislaan 320, 1098 SM Amsterdam, The Netherlands.
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22
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Verkuyl JM, Joëls M. Effect of adrenalectomy on miniature inhibitory postsynaptic currents in the paraventricular nucleus of the hypothalamus. J Neurophysiol 2003; 89:237-45. [PMID: 12522175 DOI: 10.1152/jn.00401.2002] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [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] Open
Abstract
Within the rat paraventricular nucleus of the hypothalamus two types of neurons have been distinguished based on morphological appearance, i.e., parvocellular and magnocellular neurons. The parvocellular neurons play a key role in regulating the activity of the hypothalamo-pituitary-adrenal axis, which is activated, e.g., after stress exposure. These neurons receive humoral negative feedback via the adrenal hormone corticosterone but also neuronal inhibitory input, either directly or transsynaptically relayed via GABAergic interneurons. In the present study we examined to what extent the neuronal GABAergic input is influenced by the humoral signal. To this end, miniature inhibitory postsynaptic currents (mIPSCs) were recorded in parvo- and magnocellular neurons of adrenalectomized rats, which lack corticosterone, and in sham-operated controls. Under visual control neurons in coronal slices containing the paraventricular nucleus were designated as putative parvocellular or magnocellular neurons: the former were located in the medial part of the nucleus and displayed a small fusiform soma; the latter were mostly located in the lateral part and were recognized by their large round soma. Compared with putative magnocellular neurons, parvocellular neurons generally exhibited a lower membrane capacitance, lower mIPSC frequency, and smaller mIPSC amplitude. Following adrenalectomy, the mIPSC frequency was significantly enhanced in parvo- but not magnocellular neurons. Other properties of the cells were not affected. In a second series of experiments we examined whether the increase in mIPSC frequency was due to the absence of corticosterone or caused by other effects related to adrenalectomy. The data support the former explanation since implantation of a corticosterone releasing pellet after adrenalectomy fully prevented the change in mIPSC frequency. We conclude that, in the absence of humoral negative feedback, local GABAergic input of parvocellular neurons in the paraventricular nucleus is enhanced. This may provide a compensatory mechanism necessary for maintaining controllable network activity.
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Affiliation(s)
- J M Verkuyl
- Section of Neurobiology, Swammerdam Institute for Life Sciences, University of Amsterdam, The Netherlands.
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