101
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Pease-Raissi SE, Chan JR. Building a (w)rapport between neurons and oligodendroglia: Reciprocal interactions underlying adaptive myelination. Neuron 2021; 109:1258-1273. [PMID: 33621477 PMCID: PMC8068592 DOI: 10.1016/j.neuron.2021.02.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/12/2021] [Accepted: 01/29/2021] [Indexed: 12/27/2022]
Abstract
Myelin, multilayered lipid-rich membrane extensions formed by oligodendrocytes around neuronal axons, is essential for fast and efficient action potential propagation in the central nervous system. Initially thought to be a static and immutable process, myelination is now appreciated to be a dynamic process capable of responding to and modulating neuronal function throughout life. While the importance of this type of plasticity, called adaptive myelination, is now well accepted, we are only beginning to understand the underlying cellular and molecular mechanisms by which neurons communicate experience-driven circuit activation to oligodendroglia and precisely how changes in oligodendrocytes and their myelin refine neuronal function. Here, we review recent findings addressing this reciprocal relationship in which neurons alter oligodendroglial form and oligodendrocytes conversely modulate neuronal function.
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Affiliation(s)
- Sarah E Pease-Raissi
- Weill Institute for Neuroscience, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Jonah R Chan
- Weill Institute for Neuroscience, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA.
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102
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Mapping Astrocyte Transcriptional Signatures in Response to Neuroactive Compounds. Int J Mol Sci 2021; 22:ijms22083975. [PMID: 33921461 PMCID: PMC8069033 DOI: 10.3390/ijms22083975] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/21/2021] [Accepted: 03/22/2021] [Indexed: 01/11/2023] Open
Abstract
Astrocytes play central roles in normal brain function and are critical components of synaptic networks that oversee behavioral outputs. Despite their close affiliation with neurons, how neuronal-derived signals influence astrocyte function at the gene expression level remains poorly characterized, largely due to difficulties associated with dissecting neuron- versus astrocyte-specific effects. Here, we use an in vitro system of stem cell-derived astrocytes to identify gene expression profiles in astrocytes that are influenced by neurons and regulate astrocyte development. Furthermore, we show that neurotransmitters and neuromodulators induce distinct transcriptomic and chromatin accessibility changes in astrocytes that are unique to each of these neuroactive compounds. These findings are highlighted by the observation that noradrenaline has a more profound effect on transcriptional profiles of astrocytes compared to glutamate, gamma-aminobutyric acid (GABA), acetylcholine, and serotonin. This is demonstrated through enhanced noradrenaline-induced transcriptomic and chromatin accessibility changes in vitro and through enhanced calcium signaling in vivo. Taken together, our study reveals distinct transcriptomic and chromatin architecture signatures in astrocytes in response to neuronal-derived neuroactive compounds. Since astrocyte function is affected in all neurological disorders, this study provides a new entry point for exploring genetic mechanisms of astrocyte-neuron communication that may be dysregulated in disease.
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103
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Zehnder T, Petrelli F, Romanos J, De Oliveira Figueiredo EC, Lewis TL, Déglon N, Polleux F, Santello M, Bezzi P. Mitochondrial biogenesis in developing astrocytes regulates astrocyte maturation and synapse formation. Cell Rep 2021; 35:108952. [PMID: 33852851 DOI: 10.1016/j.celrep.2021.108952] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 01/10/2021] [Accepted: 03/15/2021] [Indexed: 01/09/2023] Open
Abstract
The mechanisms controlling the post-natal maturation of astrocytes play a crucial role in ensuring correct synaptogenesis. We show that mitochondrial biogenesis in developing astrocytes is necessary for coordinating post-natal astrocyte maturation and synaptogenesis. The astrocytic mitochondrial biogenesis depends on the transient upregulation of metabolic regulator peroxisome proliferator-activated receptor gamma (PPARγ) co-activator 1α (PGC-1α), which is controlled by metabotropic glutamate receptor 5 (mGluR5). At tissue level, the loss or downregulation of astrocytic PGC-1α sustains astrocyte proliferation, dampens astrocyte morphogenesis, and impairs the formation and function of neighboring synapses, whereas its genetic re-expression is sufficient to restore the mitochondria compartment and correct astroglial and synaptic defects. Our findings show that the developmental enhancement of mitochondrial biogenesis in astrocytes is a critical mechanism controlling astrocyte maturation and supporting synaptogenesis, thus suggesting that astrocytic mitochondria may be a therapeutic target in the case of neurodevelopmental and psychiatric disorders characterized by impaired synaptogenesis.
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Affiliation(s)
- Tamara Zehnder
- Department of Fundamental Neurosciences, Faculty of Biology and Medicine, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - Francesco Petrelli
- Department of Fundamental Neurosciences, Faculty of Biology and Medicine, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - Jennifer Romanos
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland
| | - Eva C De Oliveira Figueiredo
- Department of Fundamental Neurosciences, Faculty of Biology and Medicine, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - Tommy L Lewis
- Department of Neuroscience, Columbia University, New York, NY 10032, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10032, USA
| | - Nicole Déglon
- Department of Clinical Neurosciences, Laboratory of Neurotherapies and Neuromodulation (LNTM), Lausanne University Hospital (CHUV) and University of Lausanne, 1011 Lausanne, Switzerland; Neurosciences Research Center (CRN), Laboratory of Neurotherapies and Neuromodulation (LNTM), Lausanne University Hospital and University of Lausanne, 1011 Lausanne, Switzerland
| | - Franck Polleux
- Department of Neuroscience, Columbia University, New York, NY 10032, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10032, USA
| | - Mirko Santello
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland.
| | - Paola Bezzi
- Department of Fundamental Neurosciences, Faculty of Biology and Medicine, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland; Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy.
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104
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105
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Abstract
Philip Hasel and Shane Liddelow introduce astrocytes - glial cells that help to maintain the homeostasis of the central nervous system during development, normal physiology, and aging.
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Affiliation(s)
- Philip Hasel
- Neuroscience Institute, NYU School of Medicine, New York, NY 10016, USA
| | - Shane A Liddelow
- Neuroscience Institute, NYU School of Medicine, New York, NY 10016, USA; Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA; Department of Ophthalmology, NYU School of Medicine, New York, NY 10016, USA.
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106
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Baxter PS, Dando O, Emelianova K, He X, McKay S, Hardingham GE, Qiu J. Microglial identity and inflammatory responses are controlled by the combined effects of neurons and astrocytes. Cell Rep 2021; 34:108882. [PMID: 33761343 PMCID: PMC7994374 DOI: 10.1016/j.celrep.2021.108882] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 01/07/2021] [Accepted: 02/25/2021] [Indexed: 12/05/2022] Open
Abstract
Microglia, brain-resident macrophages, require instruction from the CNS microenvironment to maintain their identity and morphology and regulate inflammatory responses, although what mediates this is unclear. Here, we show that neurons and astrocytes cooperate to promote microglial ramification, induce expression of microglial signature genes ordinarily lost in vitro and in age and disease in vivo, and repress infection- and injury-associated gene sets. The influence of neurons and astrocytes separately on microglia is weak, indicative of synergies between these cell types, which exert their effects via a mechanism involving transforming growth factor β2 (TGF-β2) signaling. Neurons and astrocytes also combine to provide immunomodulatory cues, repressing primed microglial responses to weak inflammatory stimuli (without affecting maximal responses) and consequently limiting the feedback effects of inflammation on the neurons and astrocytes themselves. These findings explain why microglia isolated ex vivo undergo de-differentiation and inflammatory deregulation and point to how disease- and age-associated changes may be counteracted.
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Affiliation(s)
- Paul S Baxter
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh Medical School, Edinburgh EH16 4TJ, UK; Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Owen Dando
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh Medical School, Edinburgh EH16 4TJ, UK; Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Katie Emelianova
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh Medical School, Edinburgh EH16 4TJ, UK; Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Xin He
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh Medical School, Edinburgh EH16 4TJ, UK; Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Sean McKay
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh Medical School, Edinburgh EH16 4TJ, UK; Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Giles E Hardingham
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh Medical School, Edinburgh EH16 4TJ, UK; Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK.
| | - Jing Qiu
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh Medical School, Edinburgh EH16 4TJ, UK; Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK.
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107
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Hardingham GE, Petzold GC, Mehta AR. What astrocytes need to do. Lancet Neurol 2021; 20:260. [PMID: 33743235 DOI: 10.1016/s1474-4422(21)00070-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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108
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Cibelli A, Veronica Lopez-Quintero S, Mccutcheon S, Scemes E, Spray DC, Stout RF, Suadicani SO, Thi MM, Urban-Maldonado M. Generation and Characterization of Immortalized Mouse Cortical Astrocytes From Wildtype and Connexin43 Knockout Mice. Front Cell Neurosci 2021; 15:647109. [PMID: 33790744 PMCID: PMC8005635 DOI: 10.3389/fncel.2021.647109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 02/18/2021] [Indexed: 11/17/2022] Open
Abstract
We transduced mouse cortical astrocytes cultured from four litters of embryonic wildtype (WT) and connexin43 (Cx43) null mouse pups with lentiviral vector encoding hTERT and measured expression of astrocyte-specific markers up to passage 10 (p10). The immortalized cell lines thus generated (designated IWCA and IKOCA, respectively) expressed biomarkers consistent with those of neonatal astrocytes, including Cx43 from wildtype but not from Cx43-null mice, lack of Cx30, and presence of Cx26. AQP4, the water channel that is found in high abundance in astrocyte end-feet, was expressed at moderately high levels in early passages, and its mRNA and protein declined to low but still detectable levels by p10. The mRNA levels of the astrocyte biomarkers aldehyde dehydrogenase 1L1 (ALDH1L1), glutamine synthetase (GS) and glial fibrillary acidic protein (GFAP) remained relatively constant during successive passages. GS protein expression was maintained while GFAP declined with cell passaging but was still detectable at p10. Both mRNA and protein levels of glutamate transporter 1 (GLT-1) declined with passage number. Immunostaining at corresponding times was consistent with the data from Western blots and provided evidence that these proteins were expressed at appropriate intracellular locations. Consistent with our goal of generating immortalized cell lines in which Cx43 was either functionally expressed or absent, IWCA cells were found to be well coupled with respect to intercellular dye transfer and similar to primary astrocyte cultures in terms of time course of junction formation, electrical coupling strength and voltage sensitivity. Moreover, barrier function was enhanced in co-culture of the IWCA cell line with bEnd.3 microvascular endothelial cells. In addition, immunostaining revealed oblate endogenous Cx43 gap junction plaques in IWCA that were similar in appearance to those plaques obtained following transfection of IKOCA cells with fluorescent protein tagged Cx43. Re-expression of Cx43 in IKOCA cells allows experimental manipulation of connexins and live imaging of interactions between connexins and other proteins. We conclude that properties of these cell lines resemble those of primary cultured astrocytes, and they may provide useful tools in functional studies by facilitating genetic and pharmacological manipulations in the context of an astrocyte-appropriate cellular environment.
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Affiliation(s)
- Antonio Cibelli
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, United States
| | | | - Sean Mccutcheon
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, United States
| | - Eliana Scemes
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, United States
| | - David C. Spray
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, United States,Department of Medicine (Cardiology), Albert Einstein College of Medicine, New York, NY, United States,*Correspondence: David C. Spray,
| | - Randy F. Stout
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, United States,Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, New York, NY, United States,Randy J. Stout Jr.,
| | - Sylvia O. Suadicani
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, United States,Department of Urology, Albert Einstein College of Medicine, New York, NY, United States,Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY, United States
| | - Mia M. Thi
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, United States,Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY, United States,Department of Orthopaedic Surgery, Albert Einstein College of Medicine, New York, NY, United States
| | - Marcia Urban-Maldonado
- Department of Urology, Albert Einstein College of Medicine, New York, NY, United States,Department of Orthopaedic Surgery, Albert Einstein College of Medicine, New York, NY, United States
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109
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Perkins EM, Burr K, Banerjee P, Mehta AR, Dando O, Selvaraj BT, Suminaite D, Nanda J, Henstridge CM, Gillingwater TH, Hardingham GE, Wyllie DJA, Chandran S, Livesey MR. Altered network properties in C9ORF72 repeat expansion cortical neurons are due to synaptic dysfunction. Mol Neurodegener 2021; 16:13. [PMID: 33663561 PMCID: PMC7931347 DOI: 10.1186/s13024-021-00433-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 02/14/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Physiological disturbances in cortical network excitability and plasticity are established and widespread in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) patients, including those harbouring the C9ORF72 repeat expansion (C9ORF72RE) mutation - the most common genetic impairment causal to ALS and FTD. Noting that perturbations in cortical function are evidenced pre-symptomatically, and that the cortex is associated with widespread pathology, cortical dysfunction is thought to be an early driver of neurodegenerative disease progression. However, our understanding of how altered network function manifests at the cellular and molecular level is not clear. METHODS To address this we have generated cortical neurons from patient-derived iPSCs harbouring C9ORF72RE mutations, as well as from their isogenic expansion-corrected controls. We have established a model of network activity in these neurons using multi-electrode array electrophysiology. We have then mechanistically examined the physiological processes underpinning network dysfunction using a combination of patch-clamp electrophysiology, immunocytochemistry, pharmacology and transcriptomic profiling. RESULTS We find that C9ORF72RE causes elevated network burst activity, associated with enhanced synaptic input, yet lower burst duration, attributable to impaired pre-synaptic vesicle dynamics. We also show that the C9ORF72RE is associated with impaired synaptic plasticity. Moreover, RNA-seq analysis revealed dysregulated molecular pathways impacting on synaptic function. All molecular, cellular and network deficits are rescued by CRISPR/Cas9 correction of C9ORF72RE. Our study provides a mechanistic view of the early dysregulated processes that underpin cortical network dysfunction in ALS-FTD. CONCLUSION These findings suggest synaptic pathophysiology is widespread in ALS-FTD and has an early and fundamental role in driving altered network function that is thought to contribute to neurodegenerative processes in these patients. The overall importance is the identification of previously unidentified defects in pre and postsynaptic compartments affecting synaptic plasticity, synaptic vesicle stores, and network propagation, which directly impact upon cortical function.
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Affiliation(s)
- Emma M. Perkins
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Karen Burr
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK
- UK Dementia Research Institute at the University of Edinburgh, Edinburgh, EH16 4SB UK
| | - Poulomi Banerjee
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK
- UK Dementia Research Institute at the University of Edinburgh, Edinburgh, EH16 4SB UK
| | - Arpan R. Mehta
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK
- UK Dementia Research Institute at the University of Edinburgh, Edinburgh, EH16 4SB UK
| | - Owen Dando
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK
- UK Dementia Research Institute at the University of Edinburgh, Edinburgh, EH16 4SB UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Bhuvaneish T. Selvaraj
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK
- UK Dementia Research Institute at the University of Edinburgh, Edinburgh, EH16 4SB UK
| | - Daumante Suminaite
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Jyoti Nanda
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK
- UK Dementia Research Institute at the University of Edinburgh, Edinburgh, EH16 4SB UK
| | - Christopher M. Henstridge
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB UK
- Division of Systems Medicine, School of Medicine, University of Dundee, Dundee, DD1 9SY UK
| | - Thomas H. Gillingwater
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB UK
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Giles E. Hardingham
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK
- UK Dementia Research Institute at the University of Edinburgh, Edinburgh, EH16 4SB UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - David J. A. Wyllie
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK
- Centre for Brain Development and Repair, inStem, Bangalore, 560065 India
| | - Siddharthan Chandran
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB UK
- UK Dementia Research Institute at the University of Edinburgh, Edinburgh, EH16 4SB UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK
- Centre for Brain Development and Repair, inStem, Bangalore, 560065 India
| | - Matthew R. Livesey
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB UK
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, S10 2HQ UK
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110
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Baxter PS, Márkus NM, Dando O, He X, Al-Mubarak BR, Qiu J, Hardingham GE. Targeted de-repression of neuronal Nrf2 inhibits α-synuclein accumulation. Cell Death Dis 2021; 12:218. [PMID: 33637689 PMCID: PMC7910424 DOI: 10.1038/s41419-021-03507-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 02/02/2021] [Accepted: 02/05/2021] [Indexed: 12/12/2022]
Abstract
Many neurodegenerative diseases are associated with neuronal misfolded protein accumulation, indicating a need for proteostasis-promoting strategies. Here we show that de-repressing the transcription factor Nrf2, epigenetically shut-off in early neuronal development, can prevent protein aggregate accumulation. Using a paradigm of α-synuclein accumulation and clearance, we find that the classical electrophilic Nrf2 activator tBHQ promotes endogenous Nrf2-dependent α-synuclein clearance in astrocytes, but not cortical neurons, which mount no Nrf2-dependent transcriptional response. Moreover, due to neuronal Nrf2 shut-off and consequent weak antioxidant defences, electrophilic tBHQ actually induces oxidative neurotoxicity, via Nrf2-independent Jun induction. However, we find that epigenetic de-repression of neuronal Nrf2 enables them to respond to Nrf2 activators to drive α-synuclein clearance. Moreover, activation of neuronal Nrf2 expression using gRNA-targeted dCas9-based transcriptional activation complexes is sufficient to trigger Nrf2-dependent α-synuclein clearance. Thus, targeting reversal of the developmental shut-off of Nrf2 in forebrain neurons may alter neurodegenerative disease trajectory by boosting proteostasis.
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Affiliation(s)
- Paul S Baxter
- UK Dementia Research Institute at the University of Edinburgh, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK.
- Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK.
| | - Nóra M Márkus
- UK Dementia Research Institute at the University of Edinburgh, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
- Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
| | - Owen Dando
- UK Dementia Research Institute at the University of Edinburgh, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
- Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain, Edinburgh Medical School, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Xin He
- UK Dementia Research Institute at the University of Edinburgh, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
- Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
| | - Bashayer R Al-Mubarak
- UK Dementia Research Institute at the University of Edinburgh, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
- Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
| | - Jing Qiu
- UK Dementia Research Institute at the University of Edinburgh, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
- Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
| | - Giles E Hardingham
- UK Dementia Research Institute at the University of Edinburgh, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK.
- Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK.
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111
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Lundquist AJ, Gallagher TJ, Petzinger GM, Jakowec MW. Exogenous l-lactate promotes astrocyte plasticity but is not sufficient for enhancing striatal synaptogenesis or motor behavior in mice. J Neurosci Res 2021; 99:1433-1447. [PMID: 33629362 DOI: 10.1002/jnr.24804] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 01/15/2021] [Indexed: 12/21/2022]
Abstract
l-Lactate is an energetic and signaling molecule that may be produced through astrocyte-specific aerobic glycolysis and is elevated in striatal muscle during intensive exercise. l-Lactate has been shown to promote neurotrophic gene expression through astrocytes within the hippocampus, however, its role in neuroplasticity within the striatum remains unknown. This study sought to investigate the role of peripheral sources of l-lactate in promoting astrocyte-specific gene expression and morphology as well as its role in neuroplasticity within the striatum of healthy animals. Using in vitro primary astrocyte cell culture, administration of l-lactate increased the expression of the neurotrophic factors Bdnf, Gdnf, Cntf, and the immediate early gene cFos. l-Lactate's promotion of neurotrophic factor expression was mediated through the lactate receptor HCAR1 since application of the HCAR1 agonist 3,5-DHBA also increased expression of Bdnf in primary astrocytes. Similar to our previous report demonstrating exercise-induced changes in astrocytic structure within the striatum, l-lactate administration to healthy mice led to increased astrocyte morphological complexity as well as astrocyte-specific neurotrophic expression within the striatum. Our study failed to demonstrate an effect of peripheral l-lactate on synaptogenesis or motor behavior. Insufficient levels and/or inadequate delivery of l-lactate through regional cerebral blood flow within the striatum may account for the lack of these benefits. Taken together, these novel findings suggest a potential framework that links peripheral l-lactate production within muscle and intensive exercise with neuroplasticity of specific brain regions through astrocytic function.
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Affiliation(s)
- Adam J Lundquist
- Department of Neurology, University of Southern California, Los Angeles, CA, USA
| | - Tyler J Gallagher
- Department of Neurology, University of Southern California, Los Angeles, CA, USA
| | - Giselle M Petzinger
- Department of Neurology, University of Southern California, Los Angeles, CA, USA.,Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, CA, USA
| | - Michael W Jakowec
- Department of Neurology, University of Southern California, Los Angeles, CA, USA.,Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, CA, USA
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112
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Maas DA, Angulo MC. Can Enhancing Neuronal Activity Improve Myelin Repair in Multiple Sclerosis? Front Cell Neurosci 2021; 15:645240. [PMID: 33708075 PMCID: PMC7940692 DOI: 10.3389/fncel.2021.645240] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 02/01/2021] [Indexed: 12/15/2022] Open
Abstract
Enhanced neuronal activity in the healthy brain can induce de novo myelination and behavioral changes. As neuronal activity can be achieved using non-invasive measures, it may be of interest to utilize the innate ability of neuronal activity to instruct myelination as a novel strategy for myelin repair in demyelinating disorders such as multiple sclerosis (MS). Preclinical studies indicate that stimulation of neuronal activity in demyelinated lesions indeed has the potential to improve remyelination and that the stimulation paradigm is an important determinant of success. However, future studies will need to reveal the most efficient stimulation protocols as well as the biological mechanisms implicated. Nonetheless, clinical studies have already explored non-invasive brain stimulation as an attractive therapeutic approach that ameliorates MS symptomatology. However, whether symptom improvement is due to improved myelin repair remains unclear. In this mini-review, we discuss the neurobiological basis and potential of enhancing neuronal activity as a novel therapeutic approach in MS.
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Affiliation(s)
- Dorien A Maas
- Université de Paris, Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Paris, France
| | - María Cecilia Angulo
- Université de Paris, Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Paris, France.,GHU PARIS Psychiatrie et Neurosciences, Paris, France
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113
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Salmina AB, Gorina YV, Erofeev AI, Balaban PM, Bezprozvanny IB, Vlasova OL. Optogenetic and chemogenetic modulation of astroglial secretory phenotype. Rev Neurosci 2021; 32:459-479. [PMID: 33550788 DOI: 10.1515/revneuro-2020-0119] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 11/28/2020] [Indexed: 12/20/2022]
Abstract
Astrocytes play a major role in brain function and alterations in astrocyte function that contribute to the pathogenesis of many brain disorders. The astrocytes are attractive cellular targets for neuroprotection and brain tissue regeneration. Development of novel approaches to monitor and to control astroglial function is of great importance for further progress in basic neurobiology and in clinical neurology, as well as psychiatry. Recently developed advanced optogenetic and chemogenetic techniques enable precise stimulation of astrocytes in vitro and in vivo, which can be achieved by the expression of light-sensitive channels and receptors, or by expression of receptors exclusively activated by designer drugs. Optogenetic stimulation of astrocytes leads to dramatic changes in intracellular calcium concentrations and causes the release of gliotransmitters. Optogenetic and chemogenetic protocols for astrocyte activation aid in extracting novel information regarding the function of brain's neurovascular unit. This review summarizes current data obtained by this approach and discusses a potential mechanistic connection between astrocyte stimulation and changes in brain physiology.
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Affiliation(s)
- Alla B Salmina
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
- Research Institute of Molecular Medicine and Pathobiochemistry, Prof. V.F. Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - Yana V Gorina
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
- Research Institute of Molecular Medicine and Pathobiochemistry, Prof. V.F. Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - Alexander I Erofeev
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
| | - Pavel M Balaban
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Ilya B Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
| | - Olga L Vlasova
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
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114
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Xie L, Hu Y, Yan D, McQuillan P, Liu Y, Zhu S, Zhu Z, Jiang Y, Hu Z. The relationship between exposure to general anesthetic agents and the risk of developing an impulse control disorder. Pharmacol Res 2021; 165:105440. [PMID: 33493656 DOI: 10.1016/j.phrs.2021.105440] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 01/13/2021] [Accepted: 01/16/2021] [Indexed: 12/18/2022]
Abstract
Most studies examining the effect of extended exposure to general anesthetic agents (GAAs) have demonstrated that extended exposure induces both structural and functional changes in the central nervous system. These changes are frequently accompanied by neurobehavioral changes that include impulse control disorders that are generally characterized by deficits in behavioral inhibition and executive function. In this review, we will.
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Affiliation(s)
- Linghua Xie
- Department of Anesthesiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yuhan Hu
- Department of Cell Biology, Yale University, New Haven, CT, USA
| | - Dandan Yan
- Department of Anesthesiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - P McQuillan
- Department of Anesthesiology, Penn State Hershey Medical Centre, Penn State College of Medicine, Hershey, PA, USA
| | - Yue Liu
- Department of Anesthesiology, The Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shengmei Zhu
- Department of Anesthesiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhirui Zhu
- Department of Anesthesiology, The Children Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yilei Jiang
- Department of Anesthesiology, The Children Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhiyong Hu
- Department of Anesthesiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
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115
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Abstract
Astrocytes are the most abundant glial cells in the mammalian brain and directly participate in the proper functioning of the nervous system by regulating ion homeostasis, controlling glutamate reuptake, and maintaining the blood-brain barrier. In the last two decades, a growing body of work also identified critical roles for astrocytes in regulating synaptic connectivity. Stemming from the observation that functional and morphological development of astrocytes occur concurrently with synapse formation and maturation, these studies revealed that both developmental processes are directly linked. In fact, astrocytes both physically contact numerous synaptic structures and actively instruct many aspects of synaptic development and function via a plethora of secreted and adhesion-based molecular signals. The complex astrocyte-to-neuron signaling modalities control different stages of synaptic development such as regulating the initial formation of structural synapses as well as their functional maturation. Furthermore, the synapse-modulating functions of astrocytes are evolutionarily conserved and contribute to the development and plasticity of diverse classes of synapses and circuits throughout the central nervous system. Importantly, because impaired synapse formation and function is a hallmark of many neurodevelopmental disorders, deficits in astrocytes are likely to be major contributors to disease pathogenesis. In this chapter, we review our current understanding of the cellular and molecular mechanisms by which astrocytes contribute to synapse development and discuss the bidirectional secretion-based and contact-mediated mechanisms responsible for these essential developmental processes.
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Affiliation(s)
- Christabel X Tan
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States
| | - Caley J Burrus Lane
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States; Department of Neurobiology, Duke University Medical Center, Durham, NC, United States
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States; Department of Neurobiology, Duke University Medical Center, Durham, NC, United States; Duke Institute for Brain Sciences, Durham, NC, United States; Regeneration Next Initiative, Duke University, Durham, NC, United States.
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116
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Pawolski V, Schmidt MHH. Neuron-Glia Interaction in the Developing and Adult Enteric Nervous System. Cells 2020; 10:E47. [PMID: 33396231 PMCID: PMC7823798 DOI: 10.3390/cells10010047] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 12/17/2020] [Accepted: 12/29/2020] [Indexed: 12/31/2022] Open
Abstract
The enteric nervous system (ENS) constitutes the largest part of the peripheral nervous system. In recent years, ENS development and its neurogenetic capacity in homeostasis and allostasishave gained increasing attention. Developmentally, the neural precursors of the ENS are mainly derived from vagal and sacral neural crest cell portions. Furthermore, Schwann cell precursors, as well as endodermal pancreatic progenitors, participate in ENS formation. Neural precursorsenherite three subpopulations: a bipotent neuron-glia, a neuronal-fated and a glial-fated subpopulation. Typically, enteric neural precursors migrate along the entire bowel to the anal end, chemoattracted by glial cell-derived neurotrophic factor (GDNF) and endothelin 3 (EDN3) molecules. During migration, a fraction undergoes differentiation into neurons and glial cells. Differentiation is regulated by bone morphogenetic proteins (BMP), Hedgehog and Notch signalling. The fully formed adult ENS may react to injury and damage with neurogenesis and gliogenesis. Nevertheless, the origin of differentiating cells is currently under debate. Putative candidates are an embryonic-like enteric neural progenitor population, Schwann cell precursors and transdifferentiating glial cells. These cells can be isolated and propagated in culture as adult ENS progenitors and may be used for cell transplantation therapies for treating enteric aganglionosis in Chagas and Hirschsprung's diseases.
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Affiliation(s)
| | - Mirko H. H. Schmidt
- Institute of Anatomy, Medical Faculty Carl Gustav Carus, Technische Universität Dresden School of Medicine, 01307 Dresden, Germany;
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117
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Wahis J, Hennes M, Arckens L, Holt MG. Star power: the emerging role of astrocytes as neuronal partners during cortical plasticity. Curr Opin Neurobiol 2020; 67:174-182. [PMID: 33360483 PMCID: PMC8202513 DOI: 10.1016/j.conb.2020.12.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 11/27/2020] [Accepted: 12/03/2020] [Indexed: 12/20/2022]
Abstract
Plasticity is a fundamental property of neuronal circuits, allowing them to adapt to alterations in activation. Generally speaking, plasticity has been viewed from a 'neuron-centric' perspective, with changes in circuit function attributed to alterations in neuronal excitability, synaptic strength or neuronal connectivity. However, it is now clear that glial cells, in particular astrocytes, are key regulators of neuronal plasticity. This article reviews recent progress made in understanding astrocyte function and attempts to summarize these functions into a coherent framework that positions astrocytes as central players in the plasticity process.
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Affiliation(s)
- Jérôme Wahis
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Maroussia Hennes
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium; Laboratory of Neuroplasticity and Neuroproteomics, Department of Biology, KU Leuven, Leuven, Belgium
| | - Lutgarde Arckens
- Laboratory of Neuroplasticity and Neuroproteomics, Department of Biology, KU Leuven, Leuven, Belgium; Leuven Brain Institute, Leuven, Belgium.
| | - Matthew G Holt
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium; Leuven Brain Institute, Leuven, Belgium.
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118
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Astrocyte-secreted IL-33 mediates homeostatic synaptic plasticity in the adult hippocampus. Proc Natl Acad Sci U S A 2020; 118:2020810118. [PMID: 33443211 PMCID: PMC7817131 DOI: 10.1073/pnas.2020810118] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Synaptic plasticity in the hippocampus is important for learning and memory formation. In particular, homeostatic synaptic plasticity enables neurons to restore their activity levels in response to chronic neuronal activity changes. While astrocytes modulate synaptic functions via the secretion of factors, the underlying molecular mechanisms remain unclear. Here, we show that suppression of hippocampal neuronal activity increases cytokine IL-33 release from astrocytes in the CA1 region. Activation of IL-33 and its neuronal ST2 receptor complex promotes functional excitatory synapse formation. Moreover, IL-33/ST2 signaling is important for the neuronal activity blockade-induced increase of CA1 excitatory synapses in vivo and spatial memory formation. This study suggests that astrocyte-secreted IL-33 acts as a negative feedback control signal to regulate hippocampal homeostatic synaptic plasticity. Hippocampal synaptic plasticity is important for learning and memory formation. Homeostatic synaptic plasticity is a specific form of synaptic plasticity that is induced upon prolonged changes in neuronal activity to maintain network homeostasis. While astrocytes are important regulators of synaptic transmission and plasticity, it is largely unclear how they interact with neurons to regulate synaptic plasticity at the circuit level. Here, we show that neuronal activity blockade selectively increases the expression and secretion of IL-33 (interleukin-33) by astrocytes in the hippocampal cornu ammonis 1 (CA1) subregion. This IL-33 stimulates an increase in excitatory synapses and neurotransmission through the activation of neuronal IL-33 receptor complex and synaptic recruitment of the scaffold protein PSD-95. We found that acute administration of tetrodotoxin in hippocampal slices or inhibition of hippocampal CA1 excitatory neurons by optogenetic manipulation increases IL-33 expression in CA1 astrocytes. Furthermore, IL-33 administration in vivo promotes the formation of functional excitatory synapses in hippocampal CA1 neurons, whereas conditional knockout of IL-33 in CA1 astrocytes decreases the number of excitatory synapses therein. Importantly, blockade of IL-33 and its receptor signaling in vivo by intracerebroventricular administration of its decoy receptor inhibits homeostatic synaptic plasticity in CA1 pyramidal neurons and impairs spatial memory formation in mice. These results collectively reveal an important role of astrocytic IL-33 in mediating the negative-feedback signaling mechanism in homeostatic synaptic plasticity, providing insights into how astrocytes maintain hippocampal network homeostasis.
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119
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Todd AC, Hardingham GE. The Regulation of Astrocytic Glutamate Transporters in Health and Neurodegenerative Diseases. Int J Mol Sci 2020; 21:E9607. [PMID: 33348528 PMCID: PMC7766851 DOI: 10.3390/ijms21249607] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 12/04/2020] [Accepted: 12/11/2020] [Indexed: 12/24/2022] Open
Abstract
The astrocytic glutamate transporters excitatory amino acid transporters 1 and 2 (EAAT1 and EAAT2) play a key role in nervous system function to maintain extracellular glutamate levels at low levels. In physiology, this is essential for the rapid uptake of synaptically released glutamate, maintaining the temporal fidelity of synaptic transmission. However, EAAT1/2 hypo-expression or hypo-function are implicated in several disorders, including epilepsy and neurodegenerative diseases, as well as being observed naturally with aging. This not only disrupts synaptic information transmission, but in extremis leads to extracellular glutamate accumulation and excitotoxicity. A key facet of EAAT1/2 expression in astrocytes is a requirement for signals from other brain cell types in order to maintain their expression. Recent evidence has shown a prominent role for contact-dependent neuron-to-astrocyte and/or endothelial cell-to-astrocyte Notch signalling for inducing and maintaining the expression of these astrocytic glutamate transporters. The relevance of this non-cell-autonomous dependence to age- and neurodegenerative disease-associated decline in astrocytic EAAT expression is discussed, plus the implications for disease progression and putative therapeutic strategies.
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Affiliation(s)
- Alison C. Todd
- UK Dementia Research Institute at the University of Edinburgh, Chancellor’s Building, Edinburgh Medical School, Edinburgh EH16 4SB, UK;
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Giles E. Hardingham
- UK Dementia Research Institute at the University of Edinburgh, Chancellor’s Building, Edinburgh Medical School, Edinburgh EH16 4SB, UK;
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
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120
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Fernández-Moncada I, Robles-Maldonado D, Castro P, Alegría K, Epp R, Ruminot I, Barros LF. Bidirectional astrocytic GLUT1 activation by elevated extracellular K . Glia 2020; 69:1012-1021. [PMID: 33277953 DOI: 10.1002/glia.23944] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 11/23/2020] [Accepted: 11/25/2020] [Indexed: 01/07/2023]
Abstract
The acute rise in interstitial K+ that accompanies neural activity couples the energy demand of neurons to the metabolism of astrocytes. The effects of elevated K+ on astrocytes include activation of aerobic glycolysis, inhibition of mitochondrial respiration and the release of lactate. Using a genetically encoded FRET glucose sensor and a novel protocol based on 3-O-methylglucose trans-acceleration and numerical simulation of glucose dynamics, we report that extracellular K+ is also a potent and reversible modulator of the astrocytic glucose transporter GLUT1. In cultured mouse astrocytes, the stimulatory effect developed within seconds, engaged both the influx and efflux modes of the transporter, and was detected even at 1 mM incremental K+ . The modulation of GLUT1 explains how astrocytes are able to maintain their glucose pool in the face of strong glycolysis stimulation. We propose that the stimulation of GLUT1 by K+ supports the production of lactate by astrocytes and the timely delivery of glucose to active neurons.
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Affiliation(s)
- Ignacio Fernández-Moncada
- Centro de Estudios Científicos, Valdivia, Chile.,INSERM U1215 NeuroCentre Magendie, Bordeaux, France
| | - Daniel Robles-Maldonado
- Centro de Estudios Científicos, Valdivia, Chile.,Universidad Austral de Chile, Valdivia, Chile
| | | | | | - Robert Epp
- Institute of Fluid Dynamics, ETH Zurich, Zurich, Switzerland
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121
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Environmental and Nutritional "Stressors" and Oligodendrocyte Dysfunction: Role of Mitochondrial and Endoplasmatic Reticulum Impairment. Biomedicines 2020; 8:biomedicines8120553. [PMID: 33265917 PMCID: PMC7760976 DOI: 10.3390/biomedicines8120553] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 11/25/2020] [Accepted: 11/27/2020] [Indexed: 12/13/2022] Open
Abstract
Oligodendrocytes are myelinating cells of the central nervous system which are generated by progenitor oligodendrocytes as a result of maturation processes. The main function of mature oligodendrocytes is to produce myelin, a lipid-rich multi-lamellar membrane that wraps tightly around neuronal axons, insulating them and facilitating nerve conduction through saltatory propagation. The myelination process requires the consumption a large amount of energy and a high metabolic turnover. Mitochondria are essential organelles which regulate many cellular functions, including energy production through oxidative phosphorylation. Any mitochondrial dysfunction impacts cellular metabolism and negatively affects the health of the organism. If the functioning of the mitochondria is unbalanced, the myelination process is impaired. When myelination has finished, oligodendrocyte will have synthesized about 40% of the total lipids present in the brain. Since lipid synthesis occurs in the cellular endoplasmic reticulum, the dysfunction of this organelle can lead to partial or deficient myelination, triggering numerous neurodegenerative diseases. In this review, the induced malfunction of oligodendrocytes by harmful exogenous stimuli has been outlined. In particular, the effects of alcohol consumption and heavy metal intake are discussed. Furthermore, the response of the oligodendrocyte to excessive mitochondrial oxidative stress and to the altered regulation of the functioning of the endoplasmic reticulum will be explored.
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122
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Wilson JE, Mart MF, Cunningham C, Shehabi Y, Girard TD, MacLullich AMJ, Slooter AJC, Ely EW. Delirium. Nat Rev Dis Primers 2020; 6:90. [PMID: 33184265 PMCID: PMC9012267 DOI: 10.1038/s41572-020-00223-4] [Citation(s) in RCA: 414] [Impact Index Per Article: 103.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/29/2020] [Indexed: 02/06/2023]
Abstract
Delirium, a syndrome characterized by an acute change in attention, awareness and cognition, is caused by a medical condition that cannot be better explained by a pre-existing neurocognitive disorder. Multiple predisposing factors (for example, pre-existing cognitive impairment) and precipitating factors (for example, urinary tract infection) for delirium have been described, with most patients having both types. Because multiple factors are implicated in the aetiology of delirium, there are likely several neurobiological processes that contribute to delirium pathogenesis, including neuroinflammation, brain vascular dysfunction, altered brain metabolism, neurotransmitter imbalance and impaired neuronal network connectivity. The Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) is the most commonly used diagnostic system upon which a reference standard diagnosis is made, although many other delirium screening tools have been developed given the impracticality of using the DSM-5 in many settings. Pharmacological treatments for delirium (such as antipsychotic drugs) are not effective, reflecting substantial gaps in our understanding of its pathophysiology. Currently, the best management strategies are multidomain interventions that focus on treating precipitating conditions, medication review, managing distress, mitigating complications and maintaining engagement to environmental issues. The effective implementation of delirium detection, treatment and prevention strategies remains a major challenge for health-care organizations globally.
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Affiliation(s)
- Jo Ellen Wilson
- Center for Critical Illness, Brain Dysfunction, and Survivorship (CIBS), Vanderbilt University Medical Center, Nashville, TN, USA.
- Department of Psychiatry and Behavioral Sciences, Division of General Psychiatry, Vanderbilt University Medical Center, Nashville, TN, USA.
| | - Matthew F Mart
- Center for Critical Illness, Brain Dysfunction, and Survivorship (CIBS), Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Medicine, Division of Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Colm Cunningham
- School of Biochemistry & Immunology, Trinity Biomedical Sciences Institute & Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Republic of Ireland
| | - Yahya Shehabi
- Monash Health School of Clinical Sciences, Monash University, Melbourne, Victoria, Australia
- Prince of Wales Clinical School of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Timothy D Girard
- Center for Critical Illness, Brain Dysfunction, and Survivorship (CIBS), Vanderbilt University Medical Center, Nashville, TN, USA
- Clinical Research, Investigation, and Systems Modeling of Acute Illness Center, Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Alasdair M J MacLullich
- Edinburgh Delirium Research Group, Geriatric Medicine, Usher Institute, University of Edinburgh, Edinburgh, Scotland, UK
| | - Arjen J C Slooter
- Department of Intensive Care Medicine and UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - E Wesley Ely
- Center for Critical Illness, Brain Dysfunction, and Survivorship (CIBS), Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Medicine, Division of Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Medicine, Division of General Internal Medicine and Public Health, Vanderbilt University Medical Center, Nashville, TN, USA
- Veteran's Affairs TN Valley, Geriatrics Research, Education and Clinical Center (GRECC), Nashville, TN, USA
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123
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Bingul D, Kalra K, Murata EM, Belser A, Dash MB. Persistent changes in extracellular lactate dynamics following synaptic potentiation. Neurobiol Learn Mem 2020; 175:107314. [PMID: 32961277 PMCID: PMC7655607 DOI: 10.1016/j.nlm.2020.107314] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/27/2020] [Accepted: 09/14/2020] [Indexed: 12/19/2022]
Abstract
A diverse array of neurometabolic coupling mechanisms exist within the brain to ensure that sufficient metabolite availability is present to meet both acute and chronic energetic demands. Excitatory synaptic activity, which produces the majority of the brain's energetic demands, triggers a rapid metabolic response including a characteristic shift towards aerobic glycolysis. Herein, astrocytically derived lactate appears to serve as an important metabolite to meet the extensive metabolic needs of activated neurons. Despite a wealth of literature characterizing lactate's role in mediating these acute metabolic needs, the extent to which lactate supports chronic energetic demands of neurons remains unclear. We hypothesized that synaptic potentiation, a ubiquitous brain phenomenon that can produce chronic alterations in synaptic activity, could necessitate persistent alterations in brain energetics. In freely-behaving rats, we induced long-term potentiation (LTP) of synapses within the dentate gyrus through high-frequency electrical stimulation (HFS) of the medial perforant pathway. Before, during, and after LTP induction, we continuously recorded extracellular lactate concentrations within the dentate gyrus to assess how changes in synaptic strength alter local glycolytic activity. Synaptic potentiation 1) altered the acute response of extracellular lactate to transient neuronal activation as evident by a larger initial dip and subsequent overshoot and 2) chronically increased local lactate availability. Although synapses were potentiated immediately following HFS, observed changes in lactate dynamics were only evident beginning ~24 h later. Once observed, however, both synaptic potentiation and altered lactate dynamics persisted for the duration of the experiment (~72 h). Persistent alterations in synaptic strength, therefore, appear to be associated with metabolic plasticity in the form of persistent augmentation of glycolytic activity.
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Affiliation(s)
- D Bingul
- Program in Neuroscience, Middlebury College, Middlebury, VT 05753, United States
| | - K Kalra
- Program in Neuroscience, Middlebury College, Middlebury, VT 05753, United States
| | - E M Murata
- Program in Neuroscience, Middlebury College, Middlebury, VT 05753, United States
| | - A Belser
- Program in Neuroscience, Middlebury College, Middlebury, VT 05753, United States
| | - M B Dash
- Program in Neuroscience, Middlebury College, Middlebury, VT 05753, United States; Department of Psychology, Middlebury College, Middlebury, VT 05753, United States.
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Abstract
ABSTRACT Cerebral small vessel disease (SVD) is a common global brain disease that causes cognitive impairment, ischemic or hemorrhagic stroke, problems with mobility, and neuropsychiatric symptoms. The brain damage, seen as focal white and deep grey matter lesions on brain magnetic resonance imaging (MRI) or computed tomography (CT), typically accumulates "covertly" and may reach an advanced state before being detected incidentally on brain scanning or causing symptoms. Patients have typically presented to different clinical services or been recruited into research focused on one clinical manifestation, perhaps explaining a lack of awareness, until recently, of the full range and complexity of SVD.In this review, we discuss the varied clinical presentations, established and emerging risk factors, relationship to SVD features on MRI or CT, and the current state of knowledge on the effectiveness of a wide range of pharmacological and lifestyle interventions. The core message is that effective assessment and clinical management of patients with SVD, as well as future advances in diagnosis, care, and treatment, will require a more "joined-up"' approach. This approach should integrate clinical expertise in stroke neurology, cognitive, and physical dysfunctions. It requires more clinical trials in order to improve pharmacological interventions, lifestyle and dietary modifications. A deeper understanding of the pathophysiology of SVD is required to steer the identification of novel interventions. An essential prerequisite to accelerating clinical trials is to improve the consistency, and standardization of clinical, cognitive and neuroimaging endpoints.
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125
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Reid MJ, Beltran-Lobo P, Johnson L, Perez-Nievas BG, Noble W. Astrocytes in Tauopathies. Front Neurol 2020; 11:572850. [PMID: 33071951 PMCID: PMC7542303 DOI: 10.3389/fneur.2020.572850] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 08/24/2020] [Indexed: 12/14/2022] Open
Abstract
Tauopathies are a group of neurodegenerative diseases characterized by the progressive accumulation across the brain of hyperphosphorylated aggregates of the microtubule-associated protein tau that vary in isoform composition, structural conformation and localization. Tau aggregates are most commonly deposited within neurons but can show differential association with astrocytes, depending on the disease. Astrocytes, the most abundant neural cells in the brain, play a major role in synapse and neuronal function, and are a key component of the glymphatic system and blood brain barrier. However, their contribution to tauopathy progression is not fully understood. Here we present a brief overview of the association of tau with astrocytes in tauopathies. We discuss findings that support a role for astrocytes in the uptake and spread of pathological tau, and we describe how alterations to astrocyte phenotype in tauopathies may cause functional alterations that impedes their ability to support neurons and/or cause neurotoxicity. The research reviewed here further highlights the importance of considering non-neuronal cells in neurodegeneration and suggests that astrocyte-directed targets that may have utility for therapeutic intervention in tauopathies.
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Affiliation(s)
- Matthew J Reid
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Paula Beltran-Lobo
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Louisa Johnson
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Beatriz Gomez Perez-Nievas
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Wendy Noble
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
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Hajka D, Duda P, Wójcicka O, Drulis-Fajdasz D, Rakus D, Gizak A. Expression of Fbp2, a Newly Discovered Constituent of Memory Formation Mechanisms, Is Regulated by Astrocyte-Neuron Crosstalk. Int J Mol Sci 2020; 21:ijms21186903. [PMID: 32962293 PMCID: PMC7555702 DOI: 10.3390/ijms21186903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 09/16/2020] [Accepted: 09/18/2020] [Indexed: 12/13/2022] Open
Abstract
Fbp2 (muscle isozyme of fructose 1,6-bisphosphatase) is a glyconeogenesis-regulating enzyme and a multifunctional protein indispensable for long-term potentiation (LTP) formation in the hippocampus. Here, we present evidence that expression of Fbp2 in murine hippocampal cell cultures is regulated by crosstalk between neurons and astrocytes. Co-culturing of the two cell types results in a decrease in Fbp2 expression in astrocytes, and its simultaneous increase in neurons, as compared to monocultures. These changes are regulated by paracrine signaling using extracellular vesicle (EV)-packed factors released to the culture medium. It is well accepted that astrocyte-neuron metabolic crosstalk plays a crucial role in shaping neuronal function, and recently we have suggested that Fbp2 is a hub linking neuronal signaling with redox and/or energetic state of brain during the formation of memory traces. Thus, our present results emphasize the importance of astrocyte-neuron crosstalk in the regulation of the cells' metabolism and synaptic plasticity, and bring us one step closer to a mechanistic understanding of the role of Fbp2 in these processes.
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127
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Bentsen MA, Rausch DM, Mirzadeh Z, Muta K, Scarlett JM, Brown JM, Herranz-Pérez V, Baquero AF, Thompson J, Alonge KM, Faber CL, Kaiyala KJ, Bennett C, Pyke C, Ratner C, Egerod KL, Holst B, Meek TH, Kutlu B, Zhang Y, Sparso T, Grove KL, Morton GJ, Kornum BR, García-Verdugo JM, Secher A, Jorgensen R, Schwartz MW, Pers TH. Transcriptomic analysis links diverse hypothalamic cell types to fibroblast growth factor 1-induced sustained diabetes remission. Nat Commun 2020; 11:4458. [PMID: 32895383 PMCID: PMC7477234 DOI: 10.1038/s41467-020-17720-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 07/15/2020] [Indexed: 12/26/2022] Open
Abstract
In rodent models of type 2 diabetes (T2D), sustained remission of hyperglycemia can be induced by a single intracerebroventricular (icv) injection of fibroblast growth factor 1 (FGF1), and the mediobasal hypothalamus (MBH) was recently implicated as the brain area responsible for this effect. To better understand the cellular response to FGF1 in the MBH, we sequenced >79,000 single-cell transcriptomes from the hypothalamus of diabetic Lepob/ob mice obtained on Days 1 and 5 after icv injection of either FGF1 or vehicle. A wide range of transcriptional responses to FGF1 was observed across diverse hypothalamic cell types, with glial cell types responding much more robustly than neurons at both time points. Tanycytes and ependymal cells were the most FGF1-responsive cell type at Day 1, but astrocytes and oligodendrocyte lineage cells subsequently became more responsive. Based on histochemical and ultrastructural evidence of enhanced cell-cell interactions between astrocytes and Agrp neurons (key components of the melanocortin system), we performed a series of studies showing that intact melanocortin signaling is required for the sustained antidiabetic action of FGF1. These data collectively suggest that hypothalamic glial cells are leading targets for the effects of FGF1 and that sustained diabetes remission is dependent on intact melanocortin signaling.
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MESH Headings
- Agouti-Related Protein/metabolism
- Animals
- Astrocytes/drug effects
- Astrocytes/metabolism
- Blood Glucose/analysis
- Cell Communication
- Cell Nucleus/drug effects
- Cell Nucleus/metabolism
- Diabetes Mellitus, Experimental/blood
- Diabetes Mellitus, Experimental/diet therapy
- Diabetes Mellitus, Experimental/etiology
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/etiology
- Diabetes Mellitus, Type 2/pathology
- Diet, High-Fat/adverse effects
- Dietary Sucrose/administration & dosage
- Dietary Sucrose/adverse effects
- Fibroblast Growth Factor 1/administration & dosage
- Humans
- Hypoglycemic Agents/administration & dosage
- Hypothalamus/cytology
- Hypothalamus/drug effects
- Hypothalamus/pathology
- Injections, Intraventricular
- Leptin/genetics
- Male
- Melanocortins/metabolism
- Melanocyte-Stimulating Hormones/administration & dosage
- Mice
- Mice, Knockout
- Neurons/drug effects
- Neurons/metabolism
- Oligodendroglia/drug effects
- Oligodendroglia/metabolism
- RNA-Seq
- Receptor, Melanocortin, Type 4/genetics
- Receptors, Melanocortin/antagonists & inhibitors
- Receptors, Melanocortin/metabolism
- Recombinant Proteins/administration & dosage
- Remission Induction/methods
- Signal Transduction/drug effects
- Single-Cell Analysis
- Stereotaxic Techniques
- Transcriptome/drug effects
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Affiliation(s)
- Marie A Bentsen
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Dylan M Rausch
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Kenjiro Muta
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
- Chakri Naruebodindra Medical Institute, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Jarrad M Scarlett
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
- Department of Pediatric Gastroenterology and Hepatology, Seattle Children's Hospital, Seattle, WA, USA
| | - Jenny M Brown
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
| | - Vicente Herranz-Pérez
- Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, Valencia, Spain
- Predepartamental Unit of Medicine, Jaume I University, Castelló de la Plana, Spain
| | - Arian F Baquero
- Obesity Research Unit, Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA
| | - Jonatan Thompson
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kimberly M Alonge
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
| | - Chelsea L Faber
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
| | - Karl J Kaiyala
- Department of Oral Health Sciences, School of Dentistry, University of Washington, Seattle, WA, USA
| | - Camdin Bennett
- Obesity Research Unit, Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA
| | - Charles Pyke
- Pathology & Imaging, Global Discovery and Development Sciences, Novo Nordisk A/S, Maaloev, Denmark
| | - Cecilia Ratner
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kristoffer L Egerod
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Birgitte Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas H Meek
- Obesity Research Unit, Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA
| | - Burak Kutlu
- Obesity Research Unit, Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA
| | - Yu Zhang
- Obesity Research Unit, Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA
| | - Thomas Sparso
- Bioinformatics and Data Mining, Global Research Technologies, Novo Nordisk A/S, Maaloev, Denmark
| | - Kevin L Grove
- Obesity Research Unit, Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA
| | - Gregory J Morton
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
| | - Birgitte R Kornum
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | | | - Anna Secher
- Diabetes Research, Global Drug Discovery, Novo Nordisk A/S, Maaloev, Denmark
| | - Rasmus Jorgensen
- Diabetes Research, Global Drug Discovery, Novo Nordisk A/S, Maaloev, Denmark
- Cytoki Pharma, Copenhagen, Denmark
| | - Michael W Schwartz
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA.
| | - Tune H Pers
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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128
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Cooper ML, Pasini S, Lambert WS, D'Alessandro KB, Yao V, Risner ML, Calkins DJ. Redistribution of metabolic resources through astrocyte networks mitigates neurodegenerative stress. Proc Natl Acad Sci U S A 2020; 117:18810-18821. [PMID: 32690710 PMCID: PMC7414143 DOI: 10.1073/pnas.2009425117] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In the central nervous system, glycogen-derived bioenergetic resources in astrocytes help promote tissue survival in response to focal neuronal stress. However, our understanding of the extent to which these resources are mobilized and utilized during neurodegeneration, especially in nearby regions that are not actively degenerating, remains incomplete. Here we modeled neurodegeneration in glaucoma, the world's leading cause of irreversible blindness, and measured how metabolites mobilize through astrocyte gap junctions composed of connexin 43 (Cx43). We elevated intraocular pressure in one eye and determined how astrocyte-derived metabolites in the contralateral optic projection responded. Remarkably, astrocyte networks expand and redistribute metabolites along distances even 10 mm in length, donating resources from the unstressed to the stressed projection in response to intraocular pressure elevation. While resource donation improves axon function and visual acuity in the directly stressed region, it renders the donating tissue susceptible to bioenergetic, structural, and physiological degradation. Intriguingly, when both projections are stressed in a WT animal, axon function and visual acuity equilibrate between the two projections even when each projection is stressed for a different length of time. This equilibration does not occur when Cx43 is not present. Thus, Cx43-mediated astrocyte metabolic networks serve as an endogenous mechanism used to mitigate bioenergetic stress and distribute the impact of neurodegenerative disease processes. Redistribution ultimately renders the donating optic nerve vulnerable to further metabolic stress, which could explain why local neurodegeneration does not remain confined, but eventually impacts healthy regions of the brain more broadly.
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Affiliation(s)
- Melissa L Cooper
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville TN 37232-0654
| | - Silvia Pasini
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville TN 37232-0654
| | - Wendi S Lambert
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville TN 37232-0654
| | - Karis B D'Alessandro
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville TN 37232-0654
| | - Vincent Yao
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville TN 37232-0654
| | - Michael L Risner
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville TN 37232-0654
| | - David J Calkins
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville TN 37232-0654
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129
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Martinez-Lozada Z, Robinson MB. Reciprocal communication between astrocytes and endothelial cells is required for astrocytic glutamate transporter 1 (GLT-1) expression. Neurochem Int 2020; 139:104787. [PMID: 32650029 DOI: 10.1016/j.neuint.2020.104787] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/15/2020] [Accepted: 06/14/2020] [Indexed: 12/12/2022]
Abstract
Astrocytes have diverse functions that are supported by their anatomic localization between neurons and blood vessels. One of these functions is the clearance of extracellular glutamate. Astrocytes clear glutamate using two Na+-dependent glutamate transporters, GLT-1 (also called EAAT2) and GLAST (also called EAAT1). GLT-1 expression increases during synaptogenesis and is a marker of astrocyte maturation. Over 20 years ago, several groups demonstrated that astrocytes in culture express little or no GLT-1 and that neurons induce expression. We recently demonstrated that co-culturing endothelia with mouse astrocytes also induced expression of GLT-1 and GLAST. These increases were blocked by an inhibitor of γ-secretase. This and other observations are consistent with the hypothesis that Notch signaling is required, but the ligands involved were not identified. In the present study, we used rat astrocyte cultures to further define the mechanisms by which endothelia induce expression of GLT-1 and GLAST. We found that co-cultures of astrocytes and endothelia express higher levels of GLT-1 and GLAST protein and mRNA. That endothelia activate Hes5, a transcription factor target of Notch, in astrocytes. Using recombinant Notch ligands, anti-Notch ligand neutralizing antibodies, and shRNAs, we provide evidence that both Dll1 and Dll4 contribute to endothelia-dependent regulation of GLT-1. We also provide evidence that astrocytes secrete a factor(s) that induces expression of Dll4 in endothelia and that this effect is required for Notch-dependent induction of GLT-1. Together these studies indicate that reciprocal communication between astrocytes and endothelia is required for appropriate astrocyte maturation and that endothelia likely deploy additional non-Notch signals to induce GLT-1.
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Affiliation(s)
- Zila Martinez-Lozada
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA, 19104-4318
| | - Michael B Robinson
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA, 19104-4318; Systems Pharmacology and Translational Therapeutics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, 19104-4318, USA.
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130
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Fernández-García S, Sancho-Balsells A, Longueville S, Hervé D, Gruart A, Delgado-García JM, Alberch J, Giralt A. Astrocytic BDNF and TrkB regulate severity and neuronal activity in mouse models of temporal lobe epilepsy. Cell Death Dis 2020; 11:411. [PMID: 32483154 PMCID: PMC7264221 DOI: 10.1038/s41419-020-2615-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 05/15/2020] [Accepted: 05/18/2020] [Indexed: 12/15/2022]
Abstract
Astrocytes have emerged as crucial regulators of neuronal network activity, synapse formation, and underlying behavioral and cognitive processes. Despite some pathways have been identified, the communication between astrocytes and neurons remains to be completely elucidated. Unraveling this communication is crucial to design potential treatments for neurological disorders like temporal lobe epilepsy (TLE). The BDNF and TrkB molecules have emerged as very promising therapeutic targets. However, their modulation can be accompanied by several off-target effects such as excitotoxicity in case of uncontrolled upregulation or dementia, amnesia, and other memory disorders in case of downregulation. Here, we show that BDNF and TrkB from astrocytes modulate neuronal dysfunction in TLE models. First, conditional overexpression of BDNF from astrocytes worsened the phenotype in the lithium-pilocarpine mouse model. Our evidences pointed out to the astrocytic pro-BDNF isoform as a major player of this altered phenotype. Conversely, specific genetic deletion of BDNF in astrocytes prevented the increase in the number of firing neurons and the global firing rate in an in vitro model of TLE. Regarding to the TrkB, we generated mice with a genetic deletion of TrkB specifically in hippocampal neurons or astrocytes. Interestingly, both lines displayed neuroprotection in the lithium-pilocarpine model but only the mice with genetic deletion of TrkB in astrocytes showed significantly preserved spatial learning skills. These data identify the astrocytic BDNF and TrkB molecules as promising therapeutic targets for the treatment of TLE.
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Affiliation(s)
- Sara Fernández-García
- Departament de Biomedicina, Facultat de Medicina, Institut de Neurociències, Universitat de Barcelona, 08036, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036, Barcelona, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031, Madrid, Spain
| | - Anna Sancho-Balsells
- Departament de Biomedicina, Facultat de Medicina, Institut de Neurociències, Universitat de Barcelona, 08036, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036, Barcelona, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031, Madrid, Spain
| | - Sophie Longueville
- Inserm UMR-S 1270, 75005, Paris, France.,Sorbonne Université, Science and Engineering Faculty, 75005, Paris, France.,Institut du Fer a Moulin, 75005, Paris, France
| | - Denis Hervé
- Inserm UMR-S 1270, 75005, Paris, France.,Sorbonne Université, Science and Engineering Faculty, 75005, Paris, France.,Institut du Fer a Moulin, 75005, Paris, France
| | - Agnès Gruart
- Division of Neurosciences, Pablo de Olavide University, 41013, Seville, Spain
| | | | - Jordi Alberch
- Departament de Biomedicina, Facultat de Medicina, Institut de Neurociències, Universitat de Barcelona, 08036, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036, Barcelona, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031, Madrid, Spain.,Production and Validation Center of Advanced Therapies (Creatio), Faculty of Medicine and Health Science, University of Barcelona, 08036, Barcelona, Spain
| | - Albert Giralt
- Departament de Biomedicina, Facultat de Medicina, Institut de Neurociències, Universitat de Barcelona, 08036, Barcelona, Spain. .,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036, Barcelona, Spain. .,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031, Madrid, Spain. .,Production and Validation Center of Advanced Therapies (Creatio), Faculty of Medicine and Health Science, University of Barcelona, 08036, Barcelona, Spain.
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131
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Kalish BT, Barkat TR, Diel EE, Zhang EJ, Greenberg ME, Hensch TK. Single-nucleus RNA sequencing of mouse auditory cortex reveals critical period triggers and brakes. Proc Natl Acad Sci U S A 2020; 117:11744-11752. [PMID: 32404418 PMCID: PMC7261058 DOI: 10.1073/pnas.1920433117] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Auditory experience drives neural circuit refinement during windows of heightened brain plasticity, but little is known about the genetic regulation of this developmental process. The primary auditory cortex (A1) of mice exhibits a critical period for thalamocortical connectivity between postnatal days P12 and P15, during which tone exposure alters the tonotopic topography of A1. We hypothesized that a coordinated, multicellular transcriptional program governs this window for patterning of the auditory cortex. To generate a robust multicellular map of gene expression, we performed droplet-based, single-nucleus RNA sequencing (snRNA-seq) of A1 across three developmental time points (P10, P15, and P20) spanning the tonotopic critical period. We also tone-reared mice (7 kHz pips) during the 3-d critical period and collected A1 at P15 and P20. We identified and profiled both neuronal (glutamatergic and GABAergic) and nonneuronal (oligodendrocytes, microglia, astrocytes, and endothelial) cell types. By comparing normal- and tone-reared mice, we found hundreds of genes across cell types showing altered expression as a result of sensory manipulation during the critical period. Functional voltage-sensitive dye imaging confirmed GABA circuit function determines critical period onset, while Nogo receptor signaling is required for its closure. We further uncovered previously unknown effects of developmental tone exposure on trajectories of gene expression in interneurons, as well as candidate genes that might execute tonotopic plasticity. Our single-nucleus transcriptomic resource of developing auditory cortex is thus a powerful discovery platform with which to identify mediators of tonotopic plasticity.
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Affiliation(s)
- Brian T Kalish
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Tania R Barkat
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138
- Center for Brain Science, Harvard University, Cambridge, MA 02138
| | - Erin E Diel
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138
- Center for Brain Science, Harvard University, Cambridge, MA 02138
| | | | | | - Takao K Hensch
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138;
- Center for Brain Science, Harvard University, Cambridge, MA 02138
- F. M. Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115
- Child Brain Development, Canadian Institute for Advanced Research, Toronto, ON M5G 1M1, Canada
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132
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Abstract
The NMDA subtype of ionotropic glutamate receptor is a sophisticated integrator and transducer of information. NMDAR-mediated signals control diverse processes across the life course, including synaptogenesis and synaptic plasticity, as well as contribute to excitotoxic processes in neurological disorders. At the basic biophysical level, the NMDAR is a coincidence detector, requiring the co-presence of agonist, co-agonist, and membrane depolarization in order to open. However, the NMDAR is not merely a conduit for ions to flow through; it is linked on the cytoplasmic side to a large network of signaling and scaffolding proteins, primarily via the C-terminal domain of NMDAR GluN2 subunits. These physical interactions help to organize the signaling cascades downstream of NMDAR activation. Notably, the NMDAR does not come in a single form: the subunit composition of the NMDAR, particularly the GluN2 subunit subtype (GluN2A-D), influences the biophysical properties of the channel. Moreover, a growing number of studies have illuminated the extent to which GluN2 C-terminal interactions vary according to GluN2 subtype and how this impacts on the processes that NMDAR activity controls. We will review recent advances, controversies, and outstanding questions in this active area of research.
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Affiliation(s)
- Giles Hardingham
- UK Dementia Research Institute, University of Edinburgh, Edinburgh, EH16 4TJ, UK.,Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, EH8 9XD, UK
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133
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de Rus Jacquet A. Preparation and Co-Culture of iPSC-Derived Dopaminergic Neurons and Astrocytes. ACTA ACUST UNITED AC 2020; 85:e98. [PMID: 31763766 PMCID: PMC9285934 DOI: 10.1002/cpcb.98] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Induced pluripotent stem cell (iPSC)‐based models are powerful tools to study neurodegenerative diseases such as Parkinson's disease. The differentiation of patient‐derived neurons and astrocytes allows investigation of the molecular mechanisms responsible for disease onset and development. In particular, these two cell types can be mono‐ or co‐cultured to study the influence of cell‐autonomous and non‐cell‐autonomous contributors to neurodegenerative diseases. We developed a streamlined procedure to produce high‐quality/high‐purity cultures of dopaminergic neurons and astrocytes that originate from the same population of midbrain floor‐plate progenitors. This unit describes differentiation, quality control, culture parameters, and troubleshooting tips to ensure the highest quality and reproducibility of research results. © 2019 The Authors. Basic Protocol 1: Differentiation of iPSCs into midbrain‐patterned neural progenitor cells Support Protocol: Quality control of neural progenitor cells Basic Protocol 2: Differentiation of neural progenitor cells into astrocytes Basic Protocol 3: Differentiation of neural progenitor cells into dopaminergic neurons Basic Protocol 4: Co‐culture of iPSC‐derived neurons and astrocytes
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134
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Chowdhury HH. Differences in cytosolic glucose dynamics in astrocytes and adipocytes measured by FRET-based nanosensors. Biophys Chem 2020; 261:106377. [PMID: 32302866 DOI: 10.1016/j.bpc.2020.106377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 04/08/2020] [Accepted: 04/08/2020] [Indexed: 11/17/2022]
Abstract
The cellular response to fluctuations in blood glucose levels consists of integrative regulation of cell glucose uptake and glucose utilization in the cytosol, resulting in altered levels of glucose in the cytosol. Cytosolic glucose is difficult to be measured in the intact tissue, however recently methods have become available that allow measurements of glucose in single living cells with fluorescence resonance energy transfer (FRET) based protein sensors. By studying the dynamics of cytosolic glucose levels in different experimental settings, we can gain insights into the properties of plasma membrane permeability to glucose and glucose utilization in the cytosol, and how these processes are modulated by different environmental conditions, agents and enzymes. In this review, we compare the cytosolic regulation of glucose in adipocytes and astrocytes - two important regulators of energy balance and glucose homeostasis in whole body and brain, respectively, with particular emphasis on the data obtained with FRET based protein sensors as well as other biochemical and molecular approaches.
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Affiliation(s)
- Helena H Chowdhury
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, University of Ljubljana, Faculty of Medicine, 1000 Ljubljana, Slovenia; Laboratory of Cell Engineering, Celica Biomedical, 1000 Ljubljana, Slovenia.
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135
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Abstract
Astrocytes are the most abundant cell type in the central nervous system and have diverse functions in blood–brain barrier maintenance, neural circuitry formation and function, and metabolic regulation. To better understand the diverse roles of astrocytes, we will summarize what is known about astrocyte development and the challenges limiting our understanding of this process. We will also discuss new approaches and technologies advancing the field.
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Affiliation(s)
- Ekin Su Akdemir
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, 77030, USA.,Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Anna Yu-Szu Huang
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, 77030, USA.,Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Benjamin Deneen
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, 77030, USA.,Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Neurosurgery, Baylor College of Medicine, Houston, TX, 77030, USA
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136
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Hagenston AM, Bading H, Bas-Orth C. Functional Consequences of Calcium-Dependent Synapse-to-Nucleus Communication: Focus on Transcription-Dependent Metabolic Plasticity. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035287. [PMID: 31570333 DOI: 10.1101/cshperspect.a035287] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In the nervous system, calcium signals play a major role in the conversion of synaptic stimuli into transcriptional responses. Signal-regulated gene transcription is fundamental for a range of long-lasting adaptive brain functions that include learning and memory, structural plasticity of neurites and synapses, acquired neuroprotection, chronic pain, and addiction. In this review, we summarize the diverse mechanisms governing calcium-dependent transcriptional regulation associated with central nervous system plasticity. We focus on recent advances in the field of synapse-to-nucleus communication that include studies of the signal-regulated transcriptome in human neurons, identification of novel regulatory mechanisms such as activity-induced DNA double-strand breaks, and the identification of novel forms of activity- and transcription-dependent adaptations, in particular, metabolic plasticity. We summarize the reciprocal interactions between different kinds of neuroadaptations and highlight the emerging role of activity-regulated epigenetic modifiers in gating the inducibility of signal-regulated genes.
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Affiliation(s)
- Anna M Hagenston
- Department of Neurobiology, Interdisciplinary Center for Neurosciences (IZN), Heidelberg University, 69120 Heidelberg, Germany
| | - Hilmar Bading
- Department of Neurobiology, Interdisciplinary Center for Neurosciences (IZN), Heidelberg University, 69120 Heidelberg, Germany
| | - Carlos Bas-Orth
- Department of Medical Cell Biology, Institute for Anatomy and Cell Biology, Heidelberg University, 69120 Heidelberg, Germany
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137
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Hennes M, Lombaert N, Wahis J, Van den Haute C, Holt MG, Arckens L. Astrocytes shape the plastic response of adult cortical neurons to vision loss. Glia 2020; 68:2102-2118. [DOI: 10.1002/glia.23830] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 03/10/2020] [Accepted: 03/13/2020] [Indexed: 12/26/2022]
Affiliation(s)
- Maroussia Hennes
- Department of BiologyKU Leuven Leuven Belgium
- VIB KU Leuven Center for Brain & Disease Research Leuven Belgium
- Leuven Brain Institute Leuven Belgium
| | | | - Jérôme Wahis
- VIB KU Leuven Center for Brain & Disease Research Leuven Belgium
- Leuven Brain Institute Leuven Belgium
- Department of NeurosciencesKU Leuven Leuven Belgium
| | - Chris Van den Haute
- Department of Biomedical SciencesKU Leuven Leuven Belgium
- KU Leuven Viral Vector Core Leuven Belgium
| | - Matthew G. Holt
- VIB KU Leuven Center for Brain & Disease Research Leuven Belgium
- Leuven Brain Institute Leuven Belgium
- Department of NeurosciencesKU Leuven Leuven Belgium
| | - Lutgarde Arckens
- Department of BiologyKU Leuven Leuven Belgium
- Leuven Brain Institute Leuven Belgium
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138
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Pestana F, Edwards-Faret G, Belgard TG, Martirosyan A, Holt MG. No Longer Underappreciated: The Emerging Concept of Astrocyte Heterogeneity in Neuroscience. Brain Sci 2020; 10:brainsci10030168. [PMID: 32183137 PMCID: PMC7139801 DOI: 10.3390/brainsci10030168] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 03/02/2020] [Accepted: 03/05/2020] [Indexed: 12/18/2022] Open
Abstract
Astrocytes are ubiquitous in the central nervous system (CNS). These cells possess thousands of individual processes, which extend out into the neuropil, interacting with neurons, other glia and blood vessels. Paralleling the wide diversity of their interactions, astrocytes have been reported to play key roles in supporting CNS structure, metabolism, blood-brain-barrier formation and control of vascular blood flow, axon guidance, synapse formation and modulation of synaptic transmission. Traditionally, astrocytes have been studied as a homogenous group of cells. However, recent studies have uncovered a surprising degree of heterogeneity in their development and function, in both the healthy and diseased brain. A better understanding of astrocyte heterogeneity is urgently needed to understand normal brain function, as well as the role of astrocytes in response to injury and disease.
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Affiliation(s)
- Francisco Pestana
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, 3000 Leuven, Belgium;
| | - Gabriela Edwards-Faret
- Laboratory of Neuronal Wiring, VIB-KU Leuven Center for Brain and Disease Research, 3000 Leuven, Belgium;
- Life & Medical Sciences (LIMES) Institute, Faculty of Mathematics and Natural Sciences, University of Bonn, 53115 Bonn, Germany
| | | | - Araks Martirosyan
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, 3000 Leuven, Belgium;
- Correspondence: (A.M.); (M.G.H.); Tel.: +32-16-37-31-27 (M.G.H.)
| | - Matthew G. Holt
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, 3000 Leuven, Belgium;
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
- Correspondence: (A.M.); (M.G.H.); Tel.: +32-16-37-31-27 (M.G.H.)
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139
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Arce-Molina R, Cortés-Molina F, Sandoval PY, Galaz A, Alegría K, Schirmeier S, Barros LF, San Martín A. A highly responsive pyruvate sensor reveals pathway-regulatory role of the mitochondrial pyruvate carrier MPC. eLife 2020; 9:53917. [PMID: 32142409 PMCID: PMC7077990 DOI: 10.7554/elife.53917] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 03/05/2020] [Indexed: 11/25/2022] Open
Abstract
Mitochondria generate ATP and building blocks for cell growth and regeneration, using pyruvate as the main substrate. Here we introduce PyronicSF, a user-friendly GFP-based sensor of improved dynamic range that enables real-time subcellular quantitation of mitochondrial pyruvate transport, concentration and flux. We report that cultured mouse astrocytes maintain mitochondrial pyruvate in the low micromolar range, below cytosolic pyruvate, which means that the mitochondrial pyruvate carrier MPC is poised to exert ultrasensitive control on the balance between respiration and anaplerosis/gluconeogenesis. The functionality of the sensor in living tissue is demonstrated in the brain of Drosophila melanogaster larvae. Mitochondrial subpopulations are known to coexist within a given cell, which differ in their morphology, mobility, membrane potential, and vicinity to other organelles. The present tool can be used to investigate how mitochondrial diversity relates to metabolism, to study the role of MPC in disease, and to screen for small-molecule MPC modulators.
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Affiliation(s)
- Robinson Arce-Molina
- Centro de Estudios Científicos-CECs, Valdivia, Chile.,Universidad Austral de Chile, Valdivia, Chile
| | | | | | - Alex Galaz
- Centro de Estudios Científicos-CECs, Valdivia, Chile
| | - Karin Alegría
- Centro de Estudios Científicos-CECs, Valdivia, Chile
| | - Stefanie Schirmeier
- Institut für Neuro- und Verhaltensbiologie, University of Münster, Münster, Germany
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140
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Lozzi B, Huang TW, Sardar D, Huang AYS, Deneen B. Regionally Distinct Astrocytes Display Unique Transcription Factor Profiles in the Adult Brain. Front Neurosci 2020; 14:61. [PMID: 32153350 PMCID: PMC7046629 DOI: 10.3389/fnins.2020.00061] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 01/15/2020] [Indexed: 12/19/2022] Open
Abstract
Astrocytes are the most abundant type of glial cell in the central nervous system and perform a myriad of vital functions, however, the nature of their diversity remains a longstanding question in neuroscience. Using transcription factor motif discovery analysis on region-specific gene signatures from astrocytes we uncovered universal and region-specific transcription factor expression profiles. This analysis revealed that motifs for Nuclear Factor-I (NFI) are present in genes enriched in astrocytes from all regions, with NFIB and NFIX exhibiting pan-astrocyte expression in the olfactory bulb, hippocampus, cortex, and brainstem. Further analysis into region-specific motif patterns, identified Nkx3-1, Stat4, Pgr, and Nkx6-1 as prospective region-specific transcription factors. Validation studies revealed that Nkx6-1 is exclusively expressed in astrocytes in the brainstem and associates with the promoters of several brainstem specific target genes. These studies illustrate the presence of multiple transcriptional layers in astrocytes across diverse brain regions and provide a new entry point for examining how astrocyte diversity is specified and maintained.
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Affiliation(s)
- Brittney Lozzi
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, United States
| | - Teng-Wei Huang
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, United States
| | - Debosmita Sardar
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, United States
| | - Anna Yu-Szu Huang
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, United States.,Program in Developmental Biology, Baylor College of Medicine, Houston, TX, United States
| | - Benjamin Deneen
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, United States.,Program in Developmental Biology, Baylor College of Medicine, Houston, TX, United States.,Department of Neurosurgery, Baylor College of Medicine, Houston, TX, United States
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141
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Robinson MB, Lee ML, DaSilva S. Glutamate Transporters and Mitochondria: Signaling, Co-compartmentalization, Functional Coupling, and Future Directions. Neurochem Res 2020; 45:526-540. [PMID: 32002773 DOI: 10.1007/s11064-020-02974-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 01/21/2020] [Accepted: 01/22/2020] [Indexed: 12/12/2022]
Abstract
In addition to being an amino acid that is incorporated into proteins, glutamate is the most abundant neurotransmitter in the mammalian CNS, the precursor for the inhibitory neurotransmitter γ-aminobutyric acid, and one metabolic step from the tricarboxylic acid cycle intermediate α-ketoglutarate. Extracellular glutamate is cleared by a family of Na+-dependent transporters. These transporters are variably expressed by all cell types in the nervous system, but the bulk of clearance is into astrocytes. GLT-1 and GLAST (also called EAAT2 and EAAT1) mediate this activity and are extremely abundant proteins with their expression enriched in fine astrocyte processes. In this review, we will focus on three topics related to these astrocytic glutamate transporters. First, these transporters co-transport three Na+ ions and a H+ with each molecule of glutamate and counter-transport one K+; they are also coupled to a Cl- conductance. The movement of Na+ is sufficient to cause profound astrocytic depolarization, and the movement of H+ is linked to astrocytic acidification. In addition, the movement of Na+ can trigger the activation of Na+ co-transporters (e.g. Na+-Ca2+ exchangers). We will describe the ways in which these ionic movements have been linked as signals to brain function and/or metabolism. Second, these transporters co-compartmentalize with mitochondria, potentially providing a mechanism to supply glutamate to mitochondria as a source of fuel for the brain. We will provide an overview of the proteins involved, discuss the evidence that glutamate is oxidized, and then highlight some of the un-resolved issues related to glutamate oxidation. Finally, we will review evidence that ischemic insults (stroke or oxygen/glucose deprivation) cause changes in these astrocytic mitochondria and discuss the ways in which these changes have been linked to glutamate transport, glutamate transport-dependent signaling, and altered glutamate metabolism. We conclude with a broader summary of some of the unresolved issues.
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Affiliation(s)
- Michael B Robinson
- Departments of Pediatrics and Systems Pharmacology & Translational Therapeutics, Children's Hospital of Philadelphia, University of Pennsylvania, 502N, Abramson Pediatric Research Building, 3615 Civic Center Boulevard, Philadelphia, PA, 19104-4318, USA.
| | - Meredith L Lee
- Departments of Pediatrics and Systems Pharmacology & Translational Therapeutics, Children's Hospital of Philadelphia, University of Pennsylvania, 502N, Abramson Pediatric Research Building, 3615 Civic Center Boulevard, Philadelphia, PA, 19104-4318, USA
| | - Sabrina DaSilva
- Departments of Pediatrics and Systems Pharmacology & Translational Therapeutics, Children's Hospital of Philadelphia, University of Pennsylvania, 502N, Abramson Pediatric Research Building, 3615 Civic Center Boulevard, Philadelphia, PA, 19104-4318, USA
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142
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Pan Y, Monje M. Activity Shapes Neural Circuit Form and Function: A Historical Perspective. J Neurosci 2020; 40:944-954. [PMID: 31996470 PMCID: PMC6988998 DOI: 10.1523/jneurosci.0740-19.2019] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 12/07/2019] [Accepted: 12/10/2019] [Indexed: 12/30/2022] Open
Abstract
The brilliant and often prescient hypotheses of Ramon y Cajal have proven foundational for modern neuroscience, but his statement that "In adult centers the nerve paths are something fixed, ended, immutable … " is an exception that did not stand the test of empirical study. Mechanisms of cellular and circuit-level plasticity continue to shape and reshape many regions of the adult nervous system long after the neurodevelopmental period. Initially focused on neurons alone, the field has followed a meteoric trajectory in understanding of activity-regulated neurodevelopment and ongoing neuroplasticity with an arc toward appreciating neuron-glial interactions and the role that each neural cell type plays in shaping adaptable neural circuity. In this review, as part of a celebration of the 50th anniversary of Society for Neuroscience, we provide a historical perspective, following this arc of inquiry from neuronal to neuron-glial mechanisms by which activity and experience modulate circuit structure and function. The scope of this consideration is broad, and it will not be possible to cover the wealth of knowledge about all aspects of activity-dependent circuit development and plasticity in depth.
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Affiliation(s)
- Yuan Pan
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, California 94305
| | - Michelle Monje
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, California 94305
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143
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Barros LF, Ruminot I, San Martín A, Lerchundi R, Fernández-Moncada I, Baeza-Lehnert F. Aerobic Glycolysis in the Brain: Warburg and Crabtree Contra Pasteur. Neurochem Res 2020; 46:15-22. [PMID: 31981059 DOI: 10.1007/s11064-020-02964-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 01/10/2020] [Accepted: 01/16/2020] [Indexed: 12/20/2022]
Abstract
Information processing is onerous. Curiously, active brain tissue does not fully oxidize glucose and instead generates a local surplus of lactate, a phenomenon termed aerobic glycolysis. Why engage in inefficient ATP production by glycolysis when energy demand is highest and oxygen is plentiful? Aerobic glycolysis is associated to classic biochemical effects known by the names of Pasteur, Warburg and Crabtree. Here we discuss these three interdependent phenomena in brain cells, in light of high-resolution data of neuronal and astrocytic metabolism in culture, tissue slices and in vivo, acquired with genetically-encoded fluorescent sensors. These sensors are synthetic proteins that can be targeted to specific cell types and subcellular compartments, which change their fluorescence in response to variations in metabolite concentration. A major site of acute aerobic glycolysis is the astrocyte. In this cell, a Crabtree effect triggered by K+ coincides with a Warburg effect mediated by NO, superimposed on a slower longer-lasting Warburg effect caused by glutamate and possibly by NH4+. The compounded outcome is that more fuel (lactate) and more oxygen are made available to neurons, on demand. Meanwhile neurons consume both glucose and lactate, maintaining a strict balance between glycolysis and respiration, commanded by the Na+ pump. We conclude that activity-dependent Warburg and Crabtree effects in brain tissue, and the resulting aerobic glycolysis, do not reflect inefficient energy generation but the marshalling of astrocytes for the purpose of neuronal ATP generation. It remains to be seen whether neurons contribute to aerobic glycolysis under physiological conditions.
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Affiliation(s)
- L Felipe Barros
- Centro de Estudios Científicos-CECs, 5110466, Valdivia, Chile.
| | - Iván Ruminot
- Centro de Estudios Científicos-CECs, 5110466, Valdivia, Chile
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144
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Cano-Jaimez M, Tagliatti E, Mendonca PRF, Nicholson E, Vivekananda U, Kullmann DM, Volynski KE. Preparation of dissociated mouse primary neuronal cultures from long-term cryopreserved brain tissue. J Neurosci Methods 2020; 330:108452. [PMID: 31655091 PMCID: PMC7026713 DOI: 10.1016/j.jneumeth.2019.108452] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 09/15/2019] [Accepted: 09/29/2019] [Indexed: 12/20/2022]
Abstract
BACKGROUND Dissociated primary neuronal cultures are widely used as a model system to investigate the cellular and molecular properties of diverse neuronal populations and mechanisms of action potential generation and synaptic transmission. Typically, rodent primary neuronal cultures are obtained from freshly-dissociated embryonic or postnatal brain tissue, which often requires intense animal husbandry. This can strain resources when working with genetically modified mice. NEW METHOD Here we describe an experimental protocol for frozen storage of mouse hippocampi, which allows fully functional dissociated primary neuronal cultures to be prepared from cryopreserved tissue. RESULTS We show that thawed hippocampal neurons have functional properties similar to those of freshly dissociated neurons, including neuronal morphology, excitability, action potential waveform and synaptic neurotransmitter release, even after cryopreservation for several years. COMPARISON TO THE EXISTING METHODS In contrast to the existing methods, the protocol described here allows for efficient long-term storage of samples, allowing researchers to perform functional experiments on neuronal cultures from brain tissue collected in other laboratories. CONCLUSIONS We anticipate that this method will facilitate collaborations among laboratories based at distant locations and will thus optimise the use of genetically modified mouse models, in line with the 3Rs (Replacement, Reduction and Refinement) recommended for scientific use of animals in research.
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Affiliation(s)
- M Cano-Jaimez
- Dept. Clinical and Experimental Epilepsy, Queen Square, Institute of Neurology, University College London, London UK
| | - E Tagliatti
- Dept. Clinical and Experimental Epilepsy, Queen Square, Institute of Neurology, University College London, London UK
| | - P R F Mendonca
- Dept. Clinical and Experimental Epilepsy, Queen Square, Institute of Neurology, University College London, London UK
| | - E Nicholson
- Dept. Clinical and Experimental Epilepsy, Queen Square, Institute of Neurology, University College London, London UK
| | - U Vivekananda
- Dept. Clinical and Experimental Epilepsy, Queen Square, Institute of Neurology, University College London, London UK
| | - D M Kullmann
- Dept. Clinical and Experimental Epilepsy, Queen Square, Institute of Neurology, University College London, London UK
| | - K E Volynski
- Dept. Clinical and Experimental Epilepsy, Queen Square, Institute of Neurology, University College London, London UK.
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145
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Gilmour A, Poole-Warren L, Green RA. An Improved in vitro Model of Cortical Tissue. Front Neurosci 2019; 13:1349. [PMID: 31920510 PMCID: PMC6928009 DOI: 10.3389/fnins.2019.01349] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 12/02/2019] [Indexed: 11/20/2022] Open
Abstract
Intracortical electrodes for brain-machine interfaces rely on intimate contact with tissues for recording signals and stimulating neurons. However, the long-term viability of intracortical electrodes in vivo is poor, with a major contributing factor being the development of a glial scar. In vivo approaches for evaluating responses to intracortical devices are resource intensive and complex, making statistically significant, high throughput data difficult to obtain. In vitro models provide an alternative to in vivo studies; however, existing approaches have limitations which restrict the translation of the cellular reactions to the implant scenario. Notably, there is no current robust model that includes astrocytes, microglia, oligodendrocytes and neurons, the four principle cell types, critical to the health, function and wound responses of the central nervous system (CNS). In previous research a co-culture of primary mouse mature mixed glial cells and immature neural precursor cells were shown to mimic several key properties of the CNS response to implanted electrode materials. However, the method was not robust and took up to 63 days, significantly affecting reproducibility and widespread use for assessing brain-material interactions. In the current research a new co-culture approach has been developed and evaluated using immunocytochemistry and quantitative polymerase chain reaction (qPCR). The resulting method reduced the time in culture significantly and the culture model was shown to have a genetic signature similar to that of healthy adult mouse brain. This new robust CNS culture model has the potential to significantly improve the capacity to translate in vitro data to the in vivo responses.
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Affiliation(s)
- Aaron Gilmour
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
- Clem Jones Centre for Neurobiology and Stem Cell Research, Menzies Health Institute Queensland, Griffiths University, Gold Coast, QLD, Australia
| | - Laura Poole-Warren
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Rylie A Green
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
- Department of Bioengineering, Imperial College London, London, United Kingdom
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146
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Van Erum J, Valkenburg F, Van Dam D, De Deyn PP. Pentylenetetrazole-induced Seizure Susceptibility in the Tau58/4 Transgenic Mouse Model of Tauopathy. Neuroscience 2019; 425:112-122. [PMID: 31785360 DOI: 10.1016/j.neuroscience.2019.11.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 11/04/2019] [Accepted: 11/05/2019] [Indexed: 11/19/2022]
Abstract
In several tauopathies such as Alzheimer's disease (AD), an increased incidence of seizures is observed. Tau, one of the major proteins implicated in AD pathology, is an important regulator of neural network excitability and might participate in the underlying epileptic cascade. However, the mechanisms underlying this relationship are not fully elucidated. We aim to investigate this mechanism by analyzing seizure susceptibility to the convulsant pentylenetetrazole (PTZ) in a novel rodent tauopathy model. A single dose of PTZ was systemically injected in Tau58/4 transgenic mice. To investigate whether young and aged heterozygous (HET) mice exhibit a higher susceptibility to seizures in comparison with wild-type (WT) littermates, video electroencephalography (EEG) in combination with behavioral scoring according to a modified Racine scale was used. The employment of different dosage groups enabled us to characterize the dose range reliably inducing seizures. Here, we report an increased seizure susceptibility in young but not in old HET Tau58/4 mice. Young HET animals displayed more severe seizures and had a reduced latency to the first seizure compared to WTs. Also, age-related differences in susceptibility could be demonstrated for both genotypes. Identification and targeting of secondary diseases such as epilepsy, which aggravate dementia and lead to earlier institutionalization, is key. This study finds that tau pathology itself is sufficient to alter seizure susceptibility in a rodent model, indicating that the disease process is crucial in the emergence of epilepsy in patients with tauopathy.
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Affiliation(s)
- Jan Van Erum
- Laboratory of Neurochemistry and Behavior, Institute Born-Bunge, Department of Biomedical Sciences, University of Antwerp, Wilrijk (Antwerp), Belgium
| | - Femke Valkenburg
- Laboratory of Neurochemistry and Behavior, Institute Born-Bunge, Department of Biomedical Sciences, University of Antwerp, Wilrijk (Antwerp), Belgium
| | - Debby Van Dam
- Laboratory of Neurochemistry and Behavior, Institute Born-Bunge, Department of Biomedical Sciences, University of Antwerp, Wilrijk (Antwerp), Belgium; Department of Neurology and Alzheimer Center, University of Groningen and University Medical Center Groningen (UMCG), Groningen, The Netherlands
| | - Peter Paul De Deyn
- Laboratory of Neurochemistry and Behavior, Institute Born-Bunge, Department of Biomedical Sciences, University of Antwerp, Wilrijk (Antwerp), Belgium; Department of Neurology and Alzheimer Center, University of Groningen and University Medical Center Groningen (UMCG), Groningen, The Netherlands; Department of Neurology, Memory Clinic of Hospital Network Antwerp (ZNA) Middelheim and Hoge Beuken, Antwerp, Belgium.
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147
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McKay S, Ryan TJ, McQueen J, Indersmitten T, Marwick KFM, Hasel P, Kopanitsa MV, Baxter PS, Martel MA, Kind PC, Wyllie DJA, O'Dell TJ, Grant SGN, Hardingham GE, Komiyama NH. The Developmental Shift of NMDA Receptor Composition Proceeds Independently of GluN2 Subunit-Specific GluN2 C-Terminal Sequences. Cell Rep 2019; 25:841-851.e4. [PMID: 30355491 PMCID: PMC6218242 DOI: 10.1016/j.celrep.2018.09.089] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 07/13/2018] [Accepted: 09/26/2018] [Indexed: 01/06/2023] Open
Abstract
The GluN2 subtype (2A versus 2B) determines biophysical properties and signaling of forebrain NMDA receptors (NMDARs). During development, GluN2A becomes incorporated into previously GluN2B-dominated NMDARs. This “switch” is proposed to be driven by distinct features of GluN2 cytoplasmic C-terminal domains (CTDs), including a unique CaMKII interaction site in GluN2B that drives removal from the synapse. However, these models remain untested in the context of endogenous NMDARs. We show that, although mutating the endogenous GluN2B CaMKII site has secondary effects on GluN2B CTD phosphorylation, the developmental changes in NMDAR composition occur normally and measures of plasticity and synaptogenesis are unaffected. Moreover, the switch proceeds normally in mice that have the GluN2A CTD replaced by that of GluN2B and commences without an observable decline in GluN2B levels but is impaired by GluN2A haploinsufficiency. Thus, GluN2A expression levels, and not GluN2 subtype-specific CTD-driven events, are the overriding factor in the developmental switch in NMDAR composition. Mutating the GluN2B CaMKII site affects phosphorylation of its C-terminal domain The developmental changes in NMDAR composition and synaptogenesis occur normally Changes in NMDAR composition do not require distinct GluN2 C-terminal domains Developmental changes in NMDAR composition are primarily sensitive to GluN2A levels
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Affiliation(s)
- Sean McKay
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; UK Dementia Research Institute at the University of Edinburgh, Chancellor's Building, Edinburgh Medical School, Edinburgh EH16 4SB, UK
| | - Tomás J Ryan
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland; Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, VIC, Australia
| | - Jamie McQueen
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; UK Dementia Research Institute at the University of Edinburgh, Chancellor's Building, Edinburgh Medical School, Edinburgh EH16 4SB, UK
| | - Tim Indersmitten
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Katie F M Marwick
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Philip Hasel
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; UK Dementia Research Institute at the University of Edinburgh, Chancellor's Building, Edinburgh Medical School, Edinburgh EH16 4SB, UK
| | - Maksym V Kopanitsa
- The Wellcome Trust Sanger Institute, Hinxton CB10 1SA, UK; UK Dementia Research Institute at Imperial College London, Hammersmith Hospital Campus, Imperial College, London W12 0NN, UK
| | - Paul S Baxter
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; UK Dementia Research Institute at the University of Edinburgh, Chancellor's Building, Edinburgh Medical School, Edinburgh EH16 4SB, UK
| | - Marc-André Martel
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Peter C Kind
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - David J A Wyllie
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Thomas J O'Dell
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Seth G N Grant
- Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; The Wellcome Trust Sanger Institute, Hinxton CB10 1SA, UK; Centre for Clinical Brain Sciences, University of Edinburgh Chancellor's Building, Edinburgh, UK
| | - Giles E Hardingham
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; UK Dementia Research Institute at the University of Edinburgh, Chancellor's Building, Edinburgh Medical School, Edinburgh EH16 4SB, UK.
| | - Noboru H Komiyama
- Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; The Wellcome Trust Sanger Institute, Hinxton CB10 1SA, UK; Centre for Clinical Brain Sciences, University of Edinburgh Chancellor's Building, Edinburgh, UK.
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148
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Rich LR, Harris W, Brown AM. The Role of Brain Glycogen in Supporting Physiological Function. Front Neurosci 2019; 13:1176. [PMID: 31749677 PMCID: PMC6842925 DOI: 10.3389/fnins.2019.01176] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/17/2019] [Indexed: 01/08/2023] Open
Abstract
Glycogen is present in the mammalian brain but occurs at concentrations so low it is unlikely to act as a conventional energy reserve. Glycogen has the intriguing feature of being located exclusively in astrocytes, but its presence benefits neurones, suggesting that glycogen is metabolized to a conduit that is transported between the glia and neural elements. In the rodent optic nerve model glycogen supports axon conduction in the form of lactate to supplement axonal metabolism during aglycemia, hypoglycemia and during periods of increased energy demand under normoglycemic conditions. In the hippocampus glycogen plays a vital role in supplying the neurones with lactate during memory formation. The physiological processes that glycogen supports, such as learning and memory, imply an inclusive and vital role in supporting physiological brain functions.
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Affiliation(s)
- Laura R Rich
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - William Harris
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Angus M Brown
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom.,Department of Neurology, University of Washington, Seattle, WA, United States
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149
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Li L, Tian E, Chen X, Chao J, Klein J, Qu Q, Sun G, Sun G, Huang Y, Warden CD, Ye P, Feng L, Li X, Cui Q, Sultan A, Douvaras P, Fossati V, Sanjana NE, Riggs AD, Shi Y. GFAP Mutations in Astrocytes Impair Oligodendrocyte Progenitor Proliferation and Myelination in an hiPSC Model of Alexander Disease. Cell Stem Cell 2019; 23:239-251.e6. [PMID: 30075130 DOI: 10.1016/j.stem.2018.07.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 04/23/2018] [Accepted: 07/16/2018] [Indexed: 10/28/2022]
Abstract
Alexander disease (AxD) is a leukodystrophy that primarily affects astrocytes and is caused by mutations in the astrocytic filament gene GFAP. While astrocytes are thought to have important roles in controlling myelination, AxD animal models do not recapitulate critical myelination phenotypes and it is therefore not clear how AxD astrocytes contribute to leukodystrophy. Here, we show that AxD patient iPSC-derived astrocytes recapitulate key features of AxD pathology such as GFAP aggregation. Moreover, AxD astrocytes inhibit proliferation of human iPSC-derived oligodendrocyte progenitor cells (OPCs) in co-culture and reduce their myelination potential. CRISPR/Cas9-based correction of GFAP mutations reversed these phenotypes. Transcriptomic analyses of AxD astrocytes and postmortem brains identified CHI3L1 as a key mediator of AxD astrocyte-induced inhibition of OPC activity. Thus, this iPSC-based model of AxD not only recapitulates patient phenotypes not observed in animal models, but also reveals mechanisms underlying disease pathology and provides a platform for assessing therapeutic interventions.
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Affiliation(s)
- Li Li
- Division of Stem Cell Biology Research, Department of Developmental and Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA; Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA
| | - E Tian
- Division of Stem Cell Biology Research, Department of Developmental and Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA
| | - Xianwei Chen
- Division of Stem Cell Biology Research, Department of Developmental and Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA
| | - Jianfei Chao
- Division of Stem Cell Biology Research, Department of Developmental and Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA
| | - Jeremy Klein
- Division of Stem Cell Biology Research, Department of Developmental and Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA
| | - Qiuhao Qu
- Division of Stem Cell Biology Research, Department of Developmental and Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA
| | - Guihua Sun
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA
| | - Guoqiang Sun
- Division of Stem Cell Biology Research, Department of Developmental and Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA
| | - Yanzhou Huang
- Division of Stem Cell Biology Research, Department of Developmental and Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA
| | - Charles D Warden
- Integrative Genomics Core, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA
| | - Peng Ye
- Division of Stem Cell Biology Research, Department of Developmental and Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA
| | - Lizhao Feng
- Division of Stem Cell Biology Research, Department of Developmental and Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA
| | - Xinqiang Li
- Division of Stem Cell Biology Research, Department of Developmental and Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA
| | - Qi Cui
- Division of Stem Cell Biology Research, Department of Developmental and Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA
| | - Abdullah Sultan
- Division of Stem Cell Biology Research, Department of Developmental and Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA
| | - Panagiotis Douvaras
- The New York Stem Cell Foundation Research Institute, New York, NY 10019, USA
| | - Valentina Fossati
- The New York Stem Cell Foundation Research Institute, New York, NY 10019, USA
| | - Neville E Sanjana
- New York Genome Center, New York, NY 10013, USA; Department of Biology, New York University, New York, NY 10003, USA; Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Arthur D Riggs
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA
| | - Yanhong Shi
- Division of Stem Cell Biology Research, Department of Developmental and Stem Cell Biology, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA; Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA.
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150
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Claes M, De Groef L, Moons L. Target-Derived Neurotrophic Factor Deprivation Puts Retinal Ganglion Cells on Death Row: Cold Hard Evidence and Caveats. Int J Mol Sci 2019; 20:E4314. [PMID: 31484425 PMCID: PMC6747494 DOI: 10.3390/ijms20174314] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 08/28/2019] [Accepted: 08/30/2019] [Indexed: 12/14/2022] Open
Abstract
Glaucoma and other optic neuropathies are characterized by axonal transport deficits. Axonal cargo travels back and forth between the soma and the axon terminus, a mechanism ensuring homeostasis and the viability of a neuron. An example of vital molecules in the axonal cargo are neurotrophic factors (NTFs). Hindered retrograde transport can cause a scarcity of those factors in the retina, which in turn can tilt the fate of retinal ganglion cells (RGCs) towards apoptosis. This postulation is one of the most widely recognized theories to explain RGC death in the disease progression of glaucoma and is known as the NTF deprivation theory. For several decades, research has been focused on the use of NTFs as a novel neuroprotective glaucoma treatment. Until now, results in animal models have been promising, but translation to the clinic has been highly disappointing. Are we lacking important knowledge to lever NTF therapies towards the therapeutic armamentarium? Or did we get the wrong end of the stick regarding the NTF deprivation theory? In this review, we will tackle the existing evidence and caveats advocating for and against the target-derived NTF deprivation theory in glaucoma, whilst digging into associated therapy efforts.
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Affiliation(s)
- Marie Claes
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
| | - Lies De Groef
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
| | - Lieve Moons
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium.
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