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Matveeva A, Watters O, Rukhadze A, Khemka N, Gentile D, Perez IF, Llorente-Folch I, Farrell C, Lo Cacciato E, Jackson J, Piazzesi A, Wischhof L, Woods I, Halang L, Hogg M, Muñoz AG, Dillon ET, Matallanas D, Arijs I, Lambrechts D, Bano D, Connolly NMC, Prehn JHM. Integrated analysis of transcriptomic and proteomic alterations in mouse models of ALS/FTD identify early metabolic adaptions with similarities to mitochondrial dysfunction disorders. Amyotroph Lateral Scler Frontotemporal Degener 2024; 25:135-149. [PMID: 37779364 DOI: 10.1080/21678421.2023.2261979] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 09/10/2023] [Indexed: 10/03/2023]
Abstract
OBJECTIVE Sporadic and familial amyotrophic lateral sclerosis (ALS) is a fatal progressive neurodegenerative disease that results in loss of motor neurons and, in some patients, associates with frontotemporal dementia (FTD). Apart from the accumulation of proteinaceous deposits, emerging literature indicates that aberrant mitochondrial bioenergetics may contribute to the onset and progression of ALS/FTD. Here we sought to investigate the pathophysiological signatures of mitochondrial dysfunction associated with ALS/FTD. METHODS By means of label-free mass spectrometry (MS) and mRNA sequencing (mRNA-seq), we report pre-symptomatic changes in the cortices of TDP-43 and FUS mutant mouse models. Using tissues from transgenic mouse models of mitochondrial diseases as a reference, we performed comparative analyses and extracted unique and common mitochondrial signatures that revealed neuroprotective compensatory mechanisms in response to early damage. RESULTS In this regard, upregulation of both Acyl-CoA Synthetase Long-Chain Family Member 3 (ACSL3) and mitochondrial tyrosyl-tRNA synthetase 2 (YARS2) were the most representative change in pre-symptomatic ALS/FTD tissues, suggesting that fatty acid beta-oxidation and mitochondrial protein translation are mechanisms of adaptation in response to ALS/FTD pathology. CONCLUSIONS Together, our unbiased integrative analyses unveil novel molecular components that may influence mitochondrial homeostasis in the earliest phase of ALS.
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Affiliation(s)
- Anna Matveeva
- Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Orla Watters
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- SFI FutureNeuro Research Centre, Dublin 2, Ireland
| | - Ani Rukhadze
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Niraj Khemka
- Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Debora Gentile
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Ivan Fernandez Perez
- Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Irene Llorente-Folch
- Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Cliona Farrell
- Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | | | - Joshua Jackson
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Antonia Piazzesi
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Lena Wischhof
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Ina Woods
- Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Luise Halang
- Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Marion Hogg
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- SFI FutureNeuro Research Centre, Dublin 2, Ireland
- Department of Biosciences, Nottingham Trent University, Clifton Campus, Nottingham, UK
| | - Amaya Garcia Muñoz
- Systems Biology Ireland, School of Medicine, University College Dublin, Dublin 4, Belfield, Ireland
| | - Eugène T Dillon
- Mass Spectrometry Resource, Conway Institute of Biomolecular & Biomedical Research, University College Dublin, Dublin 4, Ireland
| | - David Matallanas
- Systems Biology Ireland, School of Medicine, University College Dublin, Dublin 4, Belfield, Ireland
| | - Ingrid Arijs
- Laboratory for Translational Genetics, Department of Human Genetics, KU Leuven, Leuven, Belgium, and
- VIB Center for Cancer Biology, Leuven, Belgium
| | - Diether Lambrechts
- Laboratory for Translational Genetics, Department of Human Genetics, KU Leuven, Leuven, Belgium, and
- VIB Center for Cancer Biology, Leuven, Belgium
| | - Daniele Bano
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Niamh M C Connolly
- Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Jochen H M Prehn
- Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- SFI FutureNeuro Research Centre, Dublin 2, Ireland
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Llorente-Folch I, Düssmann H, Watters O, Connolly NMC, Prehn JHM. Ketone body β-hydroxybutyrate (BHB) preserves mitochondrial bioenergetics. Sci Rep 2023; 13:19664. [PMID: 37952048 PMCID: PMC10640643 DOI: 10.1038/s41598-023-46776-8] [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: 06/21/2023] [Accepted: 11/04/2023] [Indexed: 11/14/2023] Open
Abstract
The ketogenic diet is an emerging therapeutic approach for refractory epilepsy, as well as certain rare and neurodegenerative disorders. The main ketone body, β-hydroxybutyrate (BHB), is the primary energy substrate endogenously produced in a ketogenic diet, however, mechanisms of its therapeutic actions remain unknown. Here, we studied the effects of BHB on mitochondrial energetics, both in non-stimulated conditions and during glutamate-mediated hyperexcitation. We found that glutamate-induced hyperexcitation stimulated mitochondrial respiration in cultured cortical neurons, and that this response was greater in cultures supplemented with BHB than with glucose. BHB enabled a stronger and more sustained maximal uncoupled respiration, indicating that BHB enables neurons to respond more efficiently to increased energy demands such as induced during hyperexcitation. We found that cytosolic Ca2+ was required for BHB-mediated enhancement of mitochondrial function, and that this enhancement was independent of the mitochondrial glutamate-aspartate carrier, Aralar/AGC1. Our results suggest that BHB exerts its protective effects against hyperexcitation by enhancing mitochondrial function through a Ca2+-dependent, but Aralar/AGC1-independent stimulation of mitochondrial respiration.
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Affiliation(s)
- I Llorente-Folch
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland.
- Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin 2, Ireland.
- Department of Basic Sciences of Health, Area of Biochemistry and Molecular Biology, Universidad Rey Juan Carlos, 28922, Alcorcón, Madrid, Spain.
| | - H Düssmann
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland
- Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - O Watters
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland
- SFI FUTURE-NEURO Research Centre, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - N M C Connolly
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland
- Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Jochen H M Prehn
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland.
- Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin 2, Ireland.
- SFI FUTURE-NEURO Research Centre, Royal College of Surgeons in Ireland, Dublin 2, Ireland.
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3
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Kesavan J, Watters O, de Diego-Garcia L, Méndez AM, Alves M, Dinkel K, Hamacher M, Prehn JHM, Henshall DC, Engel T. Functional expression of the ATP-gated P2X7 receptor in human iPSC-derived astrocytes. Purinergic Signal 2023:10.1007/s11302-023-09957-8. [PMID: 37453017 DOI: 10.1007/s11302-023-09957-8] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Accepted: 07/04/2023] [Indexed: 07/18/2023] Open
Abstract
Activation of the ATP-gated P2X7 receptor (P2X7R), implicated in numerous diseases of the brain, can trigger diverse responses such as the release of pro-inflammatory cytokines, modulation of neurotransmission, cell proliferation or cell death. However, despite the known species-specific differences in its pharmacological properties, to date, most functional studies on P2X7R responses have been analyzed in cells from rodents or immortalised cell lines. To assess the endogenous and functional expression of P2X7Rs in human astrocytes, we differentiated human-induced pluripotent stem cells (hiPSCs) into GFAP and S100 β-expressing astrocytes. Immunostaining revealed prominent punctate P2X7R staining. P2X7R protein expression was also confirmed by Western blot. Importantly, stimulation with the potent non-selective P2X7R agonist 2',3'-O-(benzoyl-4-benzoyl)-adenosine 5'- triphosphate (BzATP) or endogenous agonist ATP induced robust calcium rises in hiPSC-derived astrocytes which were blocked by the selective P2X7R antagonists AFC-5128 or JNJ-47965567. Our findings provide evidence for the functional expression of P2X7Rs in hiPSC-derived astrocytes and support their in vitro utility in investigating the role of the P2X7R and drug screening in disorders of the central nervous system (CNS).
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Affiliation(s)
- Jaideep Kesavan
- Department of Physiology & Medical Physics, RCSI University of Medicine & Health Sciences, Dublin, D02 YN77, Ireland
- FutureNeuro, SFI Research Centre for Chronic and Rare Neurological Diseases, RCSI University of Medicine and Health Sciences, Dublin, D02 YN77, Ireland
| | - Orla Watters
- Department of Physiology & Medical Physics, RCSI University of Medicine & Health Sciences, Dublin, D02 YN77, Ireland
- FutureNeuro, SFI Research Centre for Chronic and Rare Neurological Diseases, RCSI University of Medicine and Health Sciences, Dublin, D02 YN77, Ireland
- Department of Science & Computing, SETU Waterford, Cork Rd., Co., Waterford, X91 K0EK, Ireland
| | - Laura de Diego-Garcia
- Department of Physiology & Medical Physics, RCSI University of Medicine & Health Sciences, Dublin, D02 YN77, Ireland
- Department of Optic and Optometry, Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, 28037, Spain
| | - Aida Menéndez Méndez
- Department of Physiology & Medical Physics, RCSI University of Medicine & Health Sciences, Dublin, D02 YN77, Ireland
| | - Mariana Alves
- Department of Physiology & Medical Physics, RCSI University of Medicine & Health Sciences, Dublin, D02 YN77, Ireland
| | - Klaus Dinkel
- Lead Discovery Center GmbH, Otto-Hahn-Straße 15, 44227, Dortmund, Germany
| | - Michael Hamacher
- Affectis Pharmaceuticals AG, Otto-Hahn-Straße 15, 44227, Dortmund, Germany
| | - Jochen H M Prehn
- Department of Physiology & Medical Physics, RCSI University of Medicine & Health Sciences, Dublin, D02 YN77, Ireland
- FutureNeuro, SFI Research Centre for Chronic and Rare Neurological Diseases, RCSI University of Medicine and Health Sciences, Dublin, D02 YN77, Ireland
| | - David C Henshall
- Department of Physiology & Medical Physics, RCSI University of Medicine & Health Sciences, Dublin, D02 YN77, Ireland
- FutureNeuro, SFI Research Centre for Chronic and Rare Neurological Diseases, RCSI University of Medicine and Health Sciences, Dublin, D02 YN77, Ireland
| | - Tobias Engel
- Department of Physiology & Medical Physics, RCSI University of Medicine & Health Sciences, Dublin, D02 YN77, Ireland.
- FutureNeuro, SFI Research Centre for Chronic and Rare Neurological Diseases, RCSI University of Medicine and Health Sciences, Dublin, D02 YN77, Ireland.
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4
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König HG, Watters O, Kinsella S, Ameen M, Fenner BJ, Prehn JHM. A constitutively-active IKK-complex at the axon initial segment. Brain Res 2017; 1678:356-366. [PMID: 29079505 DOI: 10.1016/j.brainres.2017.10.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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: 05/06/2017] [Revised: 10/18/2017] [Accepted: 10/20/2017] [Indexed: 01/04/2023]
Abstract
BACKGROUND Previous studies provided evidence for an accumulation of IκB-kinase (IKK) α/β at the axon initial segment (AIS), a neuronal compartment defined by ankyrin-G expression. Here we explored whether the presence of the IKK-complex at the AIS was associated with the activation of IKK signaling at this site. METHODS AND RESULTS Proximity-ligation assays (PLAs) using pan-IKKα/β, phospho-IKKα/β-specific as well as ankyrin-G specific antibodies validated their binding to proximal epitopes in the AIS, while antibodies to other phosphorylated signaling proteins showed no preference for the AIS. Small-hairpin mediated silencing of IKKβ significantly reduced anti-phospho-IKKα/β-immunoreactivities in the AIS. ank3 gene-deficient cerebellar Purkinje cells also exhibited no phosphorylated IKKα/β at the proximal region of their axons. Transient ankyrin-G overexpression in PC12 cells augmented NF-κB transactivation in an ankyrin-G death-domain dependent manner. Finally, small molecule inhibitors of IKK-activity, including Aspirin, inhibited the accumulation of activated IKK proteins in the AIS. CONCLUSION Our data suggest the existence of a constitutively-active IKK signaling complex in the AIS.
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Affiliation(s)
- Hans-Georg König
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 Saint Stephen's Green, Dublin 2, Ireland; Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, 123 Saint Stephen's Green, Dublin 2, Ireland.
| | - Orla Watters
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 Saint Stephen's Green, Dublin 2, Ireland; Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, 123 Saint Stephen's Green, Dublin 2, Ireland.
| | - Sinéad Kinsella
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 Saint Stephen's Green, Dublin 2, Ireland; Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, 123 Saint Stephen's Green, Dublin 2, Ireland.
| | - Mohammed Ameen
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 Saint Stephen's Green, Dublin 2, Ireland.
| | - Beau J Fenner
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 Saint Stephen's Green, Dublin 2, Ireland.
| | - Jochen H M Prehn
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 Saint Stephen's Green, Dublin 2, Ireland; Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, 123 Saint Stephen's Green, Dublin 2, Ireland.
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5
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Engel T, Brennan GP, Sanz-Rodriguez A, Alves M, Beamer E, Watters O, Henshall DC, Jimenez-Mateos EM. A calcium-sensitive feed-forward loop regulating the expression of the ATP-gated purinergic P2X7 receptor via specificity protein 1 and microRNA-22. Biochim Biophys Acta Mol Cell Res 2016; 1864:255-266. [PMID: 27840225 DOI: 10.1016/j.bbamcr.2016.11.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 11/05/2016] [Accepted: 11/08/2016] [Indexed: 11/26/2022]
Abstract
Cells have developed complex transcriptional regulatory mechanisms to maintain intracellular homeostasis and withstand pathophysiological stressors. Feed-forward loops comprising transcription factors that drive expression of both target gene and a microRNA as negative regulator, are gaining increasing recognition as key regulatory elements of cellular homeostasis. The ATP-gated purinergic P2X7 receptor (P2X7R) is an important driver of inflammation and has been implicated in the pathogenesis of numerous brain diseases including epilepsy. Changes in P2X7R expression have been reported in both experimental models and in epilepsy patients but the mechanism(s) controlling P2X7R levels remain incompletely understood. The specificity protein 1 (Sp1) has been shown to induce P2X7R transcription in vitro and recent data has identified microRNA-22 as a post-transcriptional repressor of P2X7R expression after seizures. In the present study we show that Sp1 can induce the transcription of both microRNA-22 and P2X7R in vitro during increased neuronal activity and in vivo in a mouse model of status epilepticus. We further show that Sp1-driven microRNA-22 transcription is calcium-sensitive and Sp1 occupancy of the microRNA-22 promoter region is blocked under conditions of seizure activity sufficient to elicit neuronal death. Taken together, our results suggest a neuronal activity-dependent P2X7R expression which is induced by the transcription factor Sp1 and repressed in a calcium-dependent manner by microRNA-22.
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Affiliation(s)
- Tobias Engel
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland.
| | - Gary P Brennan
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Amaya Sanz-Rodriguez
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Mariana Alves
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Edward Beamer
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Orla Watters
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - David C Henshall
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Eva M Jimenez-Mateos
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
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6
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Sheridan GK, Wdowicz A, Pickering M, Watters O, Halley P, O'Sullivan NC, Mooney C, O'Connell DJ, O'Connor JJ, Murphy KJ. CX3CL1 is up-regulated in the rat hippocampus during memory-associated synaptic plasticity. Front Cell Neurosci 2014; 8:233. [PMID: 25161610 PMCID: PMC4130185 DOI: 10.3389/fncel.2014.00233] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [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: 04/11/2014] [Accepted: 07/25/2014] [Indexed: 11/13/2022] Open
Abstract
Several cytokines and chemokines are now known to play normal physiological roles in the brain where they act as key regulators of communication between neurons, glia, and microglia. In particular, cytokines and chemokines can affect cardinal cellular and molecular processes of hippocampal-dependent long-term memory consolidation including synaptic plasticity, synaptic scaling and neurogenesis. The chemokine, CX3CL1 (fractalkine), has been shown to modulate synaptic transmission and long-term potentiation (LTP) in the CA1 pyramidal cell layer of the hippocampus. Here, we confirm widespread expression of CX3CL1 on mature neurons in the adult rat hippocampus. We report an up-regulation in CX3CL1 protein expression in the CA1, CA3 and dentate gyrus (DG) of the rat hippocampus 2 h after spatial learning in the water maze task. Moreover, the same temporal increase in CX3CL1 was evident following LTP-inducing theta-burst stimulation in the DG. At physiologically relevant concentrations, CX3CL1 inhibited LTP maintenance in the DG. This attenuation in dentate LTP was lost in the presence of GABAA receptor/chloride channel antagonism. CX3CL1 also had opposing actions on glutamate-mediated rise in intracellular calcium in hippocampal organotypic slice cultures in the presence and absence of GABAA receptor/chloride channel blockade. Using primary dissociated hippocampal cultures, we established that CX3CL1 reduces glutamate-mediated intracellular calcium rises in both neurons and glia in a dose dependent manner. In conclusion, CX3CL1 is up-regulated in the hippocampus during a brief temporal window following spatial learning the purpose of which may be to regulate glutamate-mediated neurotransmission tone. Our data supports a possible role for this chemokine in the protective plasticity process of synaptic scaling.
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Affiliation(s)
- Graham K Sheridan
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland ; Department of Physiology, Development and Neuroscience, University of Cambridge Cambridge, UK
| | - Anita Wdowicz
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - Mark Pickering
- School of Medicine and Medical Science, Health Sciences Centre, University College Dublin Dublin, Ireland
| | - Orla Watters
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - Paul Halley
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - Niamh C O'Sullivan
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - Claire Mooney
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - David J O'Connell
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - John J O'Connor
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - Keith J Murphy
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
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Watters O, Pickering M, Murphy R, Murphy KJ, O'Connor JJ. Automated analysis of intracellular calcium fluorescence in rat organotypic hippocampal cultures: comparison to a manual, observer based method. J Neurosci Methods 2013; 223:20-9. [PMID: 24325985 DOI: 10.1016/j.jneumeth.2013.11.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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: 05/17/2013] [Revised: 11/08/2013] [Accepted: 11/22/2013] [Indexed: 12/25/2022]
Abstract
The technical advances made in microscopy have been matched by an increase in the application of fluorescent microscopy to answer scientific questions. While analysis of fluorescent microscopy images represents a powerful tool, one must be aware of the potential pitfalls. Frequently, the analysis methods applied involve at least some manual steps which are dependent on an observers input. Typically these steps are laborious and time consuming, but more importantly they are also influenced by an individual observer's bias, drift or imprecision. This raises concerns about the repeatability and definitiveness of the reported observations. Using calcium fluorescence in organotypic hippocampal slices as an experimental platform, we demonstrate the influence that manual interventions can exert on an analysis. We show that there is a high degree of variability between observers, and that this can be sufficient to affect the outcome of an experiment. To counter this, and to eliminate the disagreement between observers, we describe an alternative fully automated method which was created using EBImage package for R. This method has the added advantage of being fully open source and customisable, allowing for this approach to be applied to other analyses.
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Affiliation(s)
- Orla Watters
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Mark Pickering
- UCD School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Robert Murphy
- Applied Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Keith J Murphy
- Applied Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - John J O'Connor
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland.
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8
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Watters O, O'Connor JJ. A role for tumor necrosis factor-α in ischemia and ischemic preconditioning. J Neuroinflammation 2011; 8:87. [PMID: 21810263 PMCID: PMC3161872 DOI: 10.1186/1742-2094-8-87] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 08/02/2011] [Indexed: 01/05/2023] Open
Abstract
During cerebral ischemia, elevation of TNF-α and glutamate to pathophysiological levels may induce dysregulation of normal synaptic processes, leading ultimately to cell death. Previous studies have shown that patients subjected to a mild transient ischemic attack within a critical time window prior to a more severe ischemic episode may show attenuation in the clinical severity of the stroke and result in a more positive functional outcome. Studies with organotypic hippocampal cultures and mixed primary hippocampal cultures have shown that prior incubation with low concentrations of glutamate and TNF-α increase the resistance of neurones to a subsequent insult from glutamate, AMPA and NMDA, while co-exposure of TNF-α and for example AMPA may have neuroprotective effects compared to cultures exposed to excitotoxic agents alone. In addition our work has shown that although glutamate and TNF-α pretreatment induces analogous levels of desensitisation of the intracellular calcium dynamics of neurons under resting conditions and in response to acute glutamate stimulation, their downstream signalling pathways involved in this response do not converge. Glutamate and TNF-α would appear to have opposing effects on resting Ca2+ levels which supports the proposal that they have distinct modes of preconditioning.
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Affiliation(s)
- Orla Watters
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
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9
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Watters O, Pickering M, O'Connor JJ. Preconditioning effects of tumor necrosis factor-α and glutamate on calcium dynamics in rat organotypic hippocampal cultures. J Neuroimmunol 2011; 234:27-39. [PMID: 21402417 DOI: 10.1016/j.jneuroim.2011.01.008] [Citation(s) in RCA: 11] [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: 07/30/2010] [Revised: 01/20/2011] [Accepted: 01/21/2011] [Indexed: 12/22/2022]
Abstract
During cerebral ischemia, elevation of TNF-α and glutamate to pathophysiological levels in the hippocampus may induce dysregulation of normal synaptic processes, leading ultimately to cell death. Previous studies have shown that patients subjected to a mild transient ischemic attack within a critical time window prior to a more severe ischemic episode may show attenuation in the clinical severity of the stroke and result in a more positive functional outcome. In this study we have investigated the individual contribution of pre-exposure to TNF-α or glutamate in the development of 'ischemic tolerance' to a subsequent insult, using organotypic hippocampal cultures. At 6 days in vitro (DIV), cultures were exposed to an acute concentration of glutamate (30 μM) or TNF-α (5 ng/ml) for 30 min, followed by 24h recovery period. We then examined the effect of the pretreatments on calcium dynamics of the cells within the CA region. We found that pretreatment with TNF-α or glutamate caused in a significant reduction in subsequent glutamate-induced Ca(2+) influx 24h later (control: 100.0 ± 0.8%, n=7769 cells; TNF-α: 76.8 ± 1.0%, n=5543 cells; glutamate: 75.3 ± 1.4%, n=3859 cells; p<0.001). Antagonism of circulating TNF-α (using infliximab, 25 μg/ml), and inhibition of the p38 MAP kinase pathway (using SB 203580, 10 μM) completely reversed this effect. However glutamate preconditioning did not appear to be mediated by p38 MAP kinase signalling, or NMDAR activation as neither SB 203580 nor D-AP5 (100 μM) altered this effect. Glutamate and TNF-α preconditioning resulted in small yet significant alterations in resting Ca(2+) levels (control: 100.0 ± 0.9%, n=2994 cells; TNF-α: 109.7 ± 1.0%, n=2884 cells; glutamate; 93.3 ± 0.8%, n=2899 cells; p<0.001), TNF-α's effect reversed by infliximab and SB 203580. Both TNF-α and glutamate also resulted in the reduction of the proportion (P) of responsive cells within the CA region of the hippocampus (control; P=0.459, 0.451 ≤ x ≥ 0.467, n=14,968 cells, TNF-α; P=0.40, 0.392 ≤ x ≥ 0.407, n=15,218; glutamate; P=0.388, 0.303 ≤ x ≥ 0.396, n=13,919 cells), and in the depression of the frequency of spontaneous Ca(2+) events (vs. control: TNF-α: p>0.00001, D=0.0454; glutamate: p>0.0001, D=0.0534). Our results suggest that attenuation in resting Ca(2+) activity and Ca(2+) related responsiveness of cells within the CA region as a result of glutamate or TNF-α pre-exposure, may contribute to the development of ischemic tolerance.
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Affiliation(s)
- Orla Watters
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
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