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Kotah JM, Kater MSJ, Brosens N, Lesuis SL, Tandari R, Blok TM, Marchetto L, Yusaf E, Koopmans FTW, Smit AB, Lucassen PJ, Krugers HJ, Verheijen MHG, Korosi A. Early-life stress and amyloidosis in mice share pathogenic pathways involving synaptic mitochondria and lipid metabolism. Alzheimers Dement 2024; 20:1637-1655. [PMID: 38055782 PMCID: PMC10984508 DOI: 10.1002/alz.13569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 11/07/2023] [Accepted: 11/09/2023] [Indexed: 12/08/2023]
Abstract
INTRODUCTION Early-life stress (ES) increases the risk for Alzheimer's disease (AD). We and others have shown that ES aggravates amyloid-beta (Aβ) pathology and promotes cognitive dysfunction in APP/PS1 mice, but underlying mechanisms remain unclear. METHODS We studied how ES affects the hippocampal synaptic proteome in wild-type (WT) and APP/PS1 mice at early and late pathological stages, and validated hits using electron microscopy and immunofluorescence. RESULTS The hippocampal synaptosomes of both ES-exposed WT and early-stage APP/PS1 mice showed a relative decrease in actin dynamics-related proteins and a relative increase in mitochondrial proteins. ES had minimal effects on older WT mice, while strongly affecting the synaptic proteome of advanced stage APP/PS1 mice, particularly the expression of astrocytic and mitochondrial proteins. DISCUSSION Our data show that ES and amyloidosis share pathogenic pathways involving synaptic mitochondrial dysfunction and lipid metabolism, which may underlie the observed impact of ES on the trajectory of AD.
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Affiliation(s)
- Janssen M. Kotah
- Brain Plasticity GroupSwammerdam Institute for Life Sciences – Center for NeuroscienceUniversity of AmsterdamAmsterdamThe Netherlands
| | - Mandy S. J. Kater
- Department of Molecular and Cellular NeurobiologyCenter for Neurogenomics and Cognitive ResearchAmsterdam NeuroscienceVrije Universiteit AmsterdamAmsterdamThe Netherlands
| | - Niek Brosens
- Brain Plasticity GroupSwammerdam Institute for Life Sciences – Center for NeuroscienceUniversity of AmsterdamAmsterdamThe Netherlands
| | - Sylvie L. Lesuis
- Brain Plasticity GroupSwammerdam Institute for Life Sciences – Center for NeuroscienceUniversity of AmsterdamAmsterdamThe Netherlands
| | - Roberta Tandari
- Brain Plasticity GroupSwammerdam Institute for Life Sciences – Center for NeuroscienceUniversity of AmsterdamAmsterdamThe Netherlands
| | - Thomas M. Blok
- Department of Molecular and Cellular NeurobiologyCenter for Neurogenomics and Cognitive ResearchAmsterdam NeuroscienceVrije Universiteit AmsterdamAmsterdamThe Netherlands
| | - Luca Marchetto
- Brain Plasticity GroupSwammerdam Institute for Life Sciences – Center for NeuroscienceUniversity of AmsterdamAmsterdamThe Netherlands
| | - Ella Yusaf
- Brain Plasticity GroupSwammerdam Institute for Life Sciences – Center for NeuroscienceUniversity of AmsterdamAmsterdamThe Netherlands
| | - Frank T. W. Koopmans
- Department of Molecular and Cellular NeurobiologyCenter for Neurogenomics and Cognitive ResearchAmsterdam NeuroscienceVrije Universiteit AmsterdamAmsterdamThe Netherlands
| | - August B. Smit
- Department of Molecular and Cellular NeurobiologyCenter for Neurogenomics and Cognitive ResearchAmsterdam NeuroscienceVrije Universiteit AmsterdamAmsterdamThe Netherlands
| | - Paul J. Lucassen
- Brain Plasticity GroupSwammerdam Institute for Life Sciences – Center for NeuroscienceUniversity of AmsterdamAmsterdamThe Netherlands
| | - Harm J. Krugers
- Brain Plasticity GroupSwammerdam Institute for Life Sciences – Center for NeuroscienceUniversity of AmsterdamAmsterdamThe Netherlands
| | - Mark H. G. Verheijen
- Department of Molecular and Cellular NeurobiologyCenter for Neurogenomics and Cognitive ResearchAmsterdam NeuroscienceVrije Universiteit AmsterdamAmsterdamThe Netherlands
| | - Aniko Korosi
- Brain Plasticity GroupSwammerdam Institute for Life Sciences – Center for NeuroscienceUniversity of AmsterdamAmsterdamThe Netherlands
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Oshima T, Kater MSJ, Huffels CFM, Wesseling EM, Middeldorp J, Hol EM, Verheijen MHG, Smit AB, Boddeke EWGM, Eggen BJL. Early amyloid-induced changes in microglia gene expression in male APP/PS1 mice. J Neurosci Res 2024; 102:e25295. [PMID: 38515329 DOI: 10.1002/jnr.25295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 12/04/2023] [Accepted: 01/12/2024] [Indexed: 03/23/2024]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease and the most common cause of dementia, characterized by deposition of extracellular amyloid-beta (Aβ) aggregates and intraneuronal hyperphosphorylated Tau. Many AD risk genes, identified in genome-wide association studies (GWAS), are expressed in microglia, the innate immune cells of the central nervous system. Specific subtypes of microglia emerged in relation to AD pathology, such as disease-associated microglia (DAMs), which increased in number with age in amyloid mouse models and in human AD cases. However, the initial transcriptional changes in these microglia in response to amyloid are still unknown. Here, to determine early changes in microglia gene expression, hippocampal microglia from male APPswe/PS1dE9 (APP/PS1) mice and wild-type littermates were isolated and analyzed by RNA sequencing (RNA-seq). By bulk RNA-seq, transcriptomic changes were detected in hippocampal microglia from 6-months-old APP/PS1 mice. By performing single-cell RNA-seq of CD11c-positive and negative microglia from 6-months-old APP/PS1 mice and analysis of the transcriptional trajectory from homeostatic to CD11c-positive microglia, we identified a set of genes that potentially reflect the initial response of microglia to Aβ.
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Affiliation(s)
- Takuya Oshima
- Department of Biomedical Sciences, Section Molecular Neurobiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Mandy S J Kater
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Christiaan F M Huffels
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Evelyn M Wesseling
- Department of Biomedical Sciences, Section Molecular Neurobiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jinte Middeldorp
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
- Department of Neurobiology & Aging, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Elly M Hol
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Mark H G Verheijen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Erik W G M Boddeke
- Department of Biomedical Sciences, Section Molecular Neurobiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
- Department of Cellular and Molecular Medicine, Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark
| | - Bart J L Eggen
- Department of Biomedical Sciences, Section Molecular Neurobiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Kater MSJ, Baumgart KF, Badia-Soteras A, Heistek TS, Carney KE, Timmerman AJ, van Weering JRT, Smit AB, van der Knaap MS, Mansvelder HD, Verheijen MHG, Min R. A novel role for MLC1 in regulating astrocyte-synapse interactions. Glia 2023; 71:1770-1785. [PMID: 37002718 DOI: 10.1002/glia.24368] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 03/14/2023] [Accepted: 03/20/2023] [Indexed: 04/04/2023]
Abstract
Loss of function of the astrocyte membrane protein MLC1 is the primary genetic cause of the rare white matter disease Megalencephalic Leukoencephalopathy with subcortical Cysts (MLC), which is characterized by disrupted brain ion and water homeostasis. MLC1 is prominently present around fluid barriers in the brain, such as in astrocyte endfeet contacting blood vessels and in processes contacting the meninges. Whether the protein plays a role in other astrocyte domains is unknown. Here, we show that MLC1 is present in distal astrocyte processes, also known as perisynaptic astrocyte processes (PAPs) or astrocyte leaflets, which closely interact with excitatory synapses in the CA1 region of the hippocampus. We find that the PAP tip extending toward excitatory synapses is shortened in Mlc1-null mice. This affects glutamatergic synaptic transmission, resulting in a reduced rate of spontaneous release events and slower glutamate re-uptake under challenging conditions. Moreover, while PAPs in wildtype mice retract from the synapse upon fear conditioning, we reveal that this structural plasticity is disturbed in Mlc1-null mice, where PAPs are already shorter. Finally, Mlc1-null mice show reduced contextual fear memory. In conclusion, our study uncovers an unexpected role for the astrocyte protein MLC1 in regulating the structure of PAPs. Loss of MLC1 alters excitatory synaptic transmission, prevents normal PAP remodeling induced by fear conditioning and disrupts contextual fear memory expression. Thus, MLC1 is a new player in the regulation of astrocyte-synapse interactions.
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Affiliation(s)
- Mandy S J Kater
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, The Netherlands
| | - Katharina F Baumgart
- Department of Child Neurology, Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers, Amsterdam Neuroscience, Amsterdam, The Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Aina Badia-Soteras
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, The Netherlands
| | - Tim S Heistek
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Karen E Carney
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, The Netherlands
| | - A Jacob Timmerman
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Jan R T van Weering
- Department of Human Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam University Medical Centers, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, The Netherlands
| | - Marjo S van der Knaap
- Department of Child Neurology, Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers, Amsterdam Neuroscience, Amsterdam, The Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Huibert D Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Mark H G Verheijen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, The Netherlands
| | - Rogier Min
- Department of Child Neurology, Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers, Amsterdam Neuroscience, Amsterdam, The Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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Lee SH, Mak A, Verheijen MHG. Comparative assessment of the effects of DREADDs and endogenously expressed GPCRs in hippocampal astrocytes on synaptic activity and memory. Front Cell Neurosci 2023; 17:1159756. [PMID: 37051110 PMCID: PMC10083367 DOI: 10.3389/fncel.2023.1159756] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 03/13/2023] [Indexed: 03/29/2023] Open
Abstract
Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) have proven themselves as one of the key in vivo techniques of modern neuroscience, allowing for unprecedented access to cellular manipulations in living animals. With respect to astrocyte research, DREADDs have become a popular method to examine the functional aspects of astrocyte activity, particularly G-protein coupled receptor (GPCR)-mediated intracellular calcium (Ca2+) and cyclic adenosine monophosphate (cAMP) dynamics. With this method it has become possible to directly link the physiological aspects of astrocytic function to cognitive processes such as memory. As a result, a multitude of studies have explored the impact of DREADD activation in astrocytes on synaptic activity and memory. However, the emergence of varying results prompts us to reconsider the degree to which DREADDs expressed in astrocytes accurately mimic endogenous GPCR activity. Here we compare the major downstream signaling mechanisms, synaptic, and behavioral effects of stimulating Gq-, Gs-, and Gi-DREADDs in hippocampal astrocytes of adult mice to those of endogenously expressed GPCRs.
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Affiliation(s)
- Sophie H. Lee
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
- Research Master’s Programme Brain and Cognitive Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Aline Mak
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Mark H. G. Verheijen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
- *Correspondence: Mark Verheijen,
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Kater MSJ, Badia-Soteras A, van Weering JRT, Smit AB, Verheijen MHG. Electron microscopy analysis of astrocyte-synapse interactions shows altered dynamics in an Alzheimer's disease mouse model. Front Cell Neurosci 2023; 17:1085690. [PMID: 36779013 PMCID: PMC9908992 DOI: 10.3389/fncel.2023.1085690] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 01/10/2023] [Indexed: 01/27/2023] Open
Abstract
Introduction Astrocyte-synapse bi-directional communication is required for neuronal development and synaptic plasticity. Astrocytes structurally interact with synapses using their distal processes also known as leaflets or perisynaptic astrocytic processes (PAPs). We recently showed that these PAPs are retracted from hippocampal synapses, and involved in the consolidation of fear memory. However, whether astrocytic synaptic coverage is affected when memory is impaired is unknown. Methods Here, we describe in detail an electron microscopy method that makes use of a large number of 2D images to investigate structural astrocyte-synapse interaction in paraformaldehyde fixed brain tissue of mice. Results and discussion We show that fear memory-induced synaptic activation reduces the interaction between the PAPs and the presynapse, but not the postsynapse, accompanied by retraction of the PAP tip from the synaptic cleft. Interestingly, this retraction is absent in the APP/PS1 mouse model of Alzheimer's disease, supporting the concept that alterations in astrocyte-synapse coverage contribute to memory processing.
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Affiliation(s)
- Mandy S. J. Kater
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Aina Badia-Soteras
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Jan R. T. van Weering
- Department of Human Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Amsterdam University Medical Center, Vrije Universiteit Medical Center, Amsterdam, Netherlands
| | - August B. Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Mark H. G. Verheijen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, Netherlands,*Correspondence: Mark H. G. Verheijen,
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Kater MSJ, Huffels CFM, Oshima T, Renckens NS, Middeldorp J, Boddeke EWGM, Smit AB, Eggen BJL, Hol EM, Verheijen MHG. Prevention of microgliosis halts early memory loss in a mouse model of Alzheimer's disease. Brain Behav Immun 2023; 107:225-241. [PMID: 36270437 DOI: 10.1016/j.bbi.2022.10.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 09/29/2022] [Accepted: 10/13/2022] [Indexed: 12/04/2022] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline, the neuropathological formation of amyloid-beta (Aβ) plaques and neurofibrillary tangles. The best cellular correlates of the early cognitive deficits in AD patients are synapse loss and gliosis. In particular, it is unclear whether the activation of microglia (microgliosis) has a neuroprotective or pathological role early in AD. Here we report that microgliosis is an early mediator of synaptic dysfunction and cognitive impairment in APP/PS1 mice, a mouse model of increased amyloidosis. We found that the appearance of microgliosis, synaptic dysfunction and behavioral impairment coincided with increased soluble Aβ42 levels, and occurred well before the presence of Aβ plaques. Inhibition of microglial activity by treatment with minocycline (MC) reduced gliosis, synaptic deficits and cognitive impairments at early pathological stages and was most effective when provided preventive, i.e., before the onset of microgliosis. Interestingly, soluble Aβ levels or Aβ plaques deposition were not affected by preventive MC treatment at an early pathological stage (4 months) whereas these were reduced upon treatment at a later stage (6 months). In conclusion, this study demonstrates the importance of early-stage prevention of microgliosis on the development of cognitive impairment in APP/PS1 mice, which might be clinically relevant in preventing memory loss and delaying AD pathogenesis.
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Affiliation(s)
- Mandy S J Kater
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Christiaan F M Huffels
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Takuya Oshima
- Department of Biomedical Sciences of Cells & Systems, Section Molecular Neurobiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Niek S Renckens
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Jinte Middeldorp
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands; Department of Neurobiology & Aging, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Erik W G M Boddeke
- Department of Biomedical Sciences of Cells & Systems, Section Molecular Neurobiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; Center for Healthy Ageing, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Bart J L Eggen
- Department of Biomedical Sciences of Cells & Systems, Section Molecular Neurobiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Elly M Hol
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Mark H G Verheijen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
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Badia-Soteras A, Heistek TS, Kater MSJ, Mak A, Negrean A, van den Oever MC, Mansvelder HD, Khakh BS, Min R, Smit AB, Verheijen MHG. Retraction of Astrocyte Leaflets From the Synapse Enhances Fear Memory. Biol Psychiatry 2022:S0006-3223(22)01705-X. [PMID: 36702661 DOI: 10.1016/j.biopsych.2022.10.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 10/07/2022] [Accepted: 10/20/2022] [Indexed: 01/28/2023]
Abstract
BACKGROUND The formation and retrieval of fear memories depends on orchestrated synaptic activity of neuronal ensembles within the hippocampus, and it is becoming increasingly evident that astrocytes residing in the environment of these synapses play a central role in shaping cellular memory representations. Astrocyte distal processes, known as leaflets, fine-tune synaptic activity by clearing neurotransmitters and limiting glutamate diffusion. However, how astroglial synaptic coverage contributes to mnemonic processing of fearful experiences remains largely unknown. METHODS We used electron microscopy to observe changes in astroglial coverage of hippocampal synapses during consolidation of fear memory in mice. To manipulate astroglial synaptic coverage, we depleted ezrin, an integral leaflet-structural protein, from hippocampal astrocytes using CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 gene editing. Next, a combination of Föster resonance energy transfer analysis, genetically encoded glutamate sensors, and whole-cell patch-clamp recordings was used to determine whether the proximity of astrocyte leaflets to the synapse is critical for synaptic integrity and function. RESULTS We found that consolidation of a recent fear memory is accompanied by a transient retraction of astrocyte leaflets from hippocampal synapses and increased activation of NMDA receptors. Accordingly, astrocyte-specific depletion of ezrin resulted in shorter astrocyte leaflets and reduced astrocyte contact with the synaptic cleft, which consequently boosted extrasynaptic glutamate diffusion and NMDA receptor activation. Importantly, after fear conditioning, these cellular phenotypes translated to increased retrieval-evoked activation of CA1 pyramidal neurons and enhanced fear memory expression. CONCLUSIONS Together, our data show that withdrawal of astrocyte leaflets from the synaptic cleft is an experience-induced, temporally regulated process that gates the strength of fear memories.
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Affiliation(s)
- Aina Badia-Soteras
- Department of Molecular and Cellular Neuroscience, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Tim S Heistek
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Mandy S J Kater
- Department of Molecular and Cellular Neuroscience, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Aline Mak
- Department of Molecular and Cellular Neuroscience, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Adrian Negrean
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Michel C van den Oever
- Department of Molecular and Cellular Neuroscience, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Huibert D Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Baljit S Khakh
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California; Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Rogier Min
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands; Department of Child Neurology, Emma Children's Hospital, Amsterdam University Medical Centers, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - August B Smit
- Department of Molecular and Cellular Neuroscience, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Mark H G Verheijen
- Department of Molecular and Cellular Neuroscience, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.
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Badia-Soteras A, de Vries J, Dykstra W, Broersen LM, Verkuyl JM, Smit AB, Verheijen MHG. High-Throughput Analysis of Astrocyte Cultures Shows Prevention of Reactive Astrogliosis by the Multi-Nutrient Combination Fortasyn Connect. Cells 2022; 11:cells11091428. [PMID: 35563732 PMCID: PMC9099974 DOI: 10.3390/cells11091428] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 04/07/2022] [Accepted: 04/20/2022] [Indexed: 12/23/2022] Open
Abstract
Astrocytes are specialized glial cells that tile the central nervous system (CNS) and perform numerous essential functions. Astrocytes react to various forms of CNS insults by altering their morphology and molecular profile, through a process known as reactive astrogliosis. Accordingly, astrocyte reactivity is apparent in many neurodegenerative diseases, among which one is Alzheimer’s disease (AD). Recent clinical trials on early-stage AD have demonstrated that Fortasyn Connect (FC), a multi-nutrient combination providing specific precursors and cofactors for phospholipid synthesis, helps to maintain neuronal functional connectivity and cognitive performance of patients. Several studies have shown that FC may act through its effects on neuronal survival and synaptogenesis, leading to reduced astrocyte reactivity, but whether FC can directly counteract astrocyte reactivity remains to be elucidated. Hence, we developed an in vitro model of reactive astrogliosis using the pro-inflammatory cytokines TNF-α and IFN-γ together with an automated high-throughput assay (AstroScan) to quantify molecular and morphological changes that accompany reactive astrogliosis. Next, we showed that FC is potent in preventing cytokine-induced reactive astrogliosis, a finding that might be of high relevance to understand the beneficial effects of FC-based interventions in the context of neurodegenerative diseases.
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Affiliation(s)
- Aina Badia-Soteras
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Faculty of Earth and Life Sciences, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands; (A.B.-S.); (J.d.V.); (W.D.); (A.B.S.)
| | - Janneke de Vries
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Faculty of Earth and Life Sciences, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands; (A.B.-S.); (J.d.V.); (W.D.); (A.B.S.)
| | - Werner Dykstra
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Faculty of Earth and Life Sciences, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands; (A.B.-S.); (J.d.V.); (W.D.); (A.B.S.)
| | - Laus M. Broersen
- Danone Nutricia Research, 3584 CT Utrecht, The Netherlands; (L.M.B.); (J.M.V.)
| | - Jan Martin Verkuyl
- Danone Nutricia Research, 3584 CT Utrecht, The Netherlands; (L.M.B.); (J.M.V.)
| | - August B. Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Faculty of Earth and Life Sciences, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands; (A.B.-S.); (J.d.V.); (W.D.); (A.B.S.)
| | - Mark H. G. Verheijen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Faculty of Earth and Life Sciences, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands; (A.B.-S.); (J.d.V.); (W.D.); (A.B.S.)
- Correspondence:
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Badia-Soteras A, Octeau JC, Verheijen MHG, Khakh BS. Assessing Neuron-Astrocyte Spatial Interactions Using the Neuron-Astrocyte Proximity Assay. Curr Protoc Neurosci 2020; 91:e91. [PMID: 32068967 PMCID: PMC7123847 DOI: 10.1002/cpns.91] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Astrocytes are morphologically complex cells with numerous close contacts with neurons at the level of their somata, branches, and branchlets. The smallest astrocyte processes make discrete contacts with synapses at scales that cannot be observed by standard light microscopy. At such contact points, astrocytes are thought to perform both homeostatic and neuromodulatory roles-functions that are proposed to be determined by their close spatial apposition. To study such spatial interactions, we previously developed a Förster resonance energy transfer (FRET)-based approach, which enables observation and tracking of the static and dynamic proximity of astrocyte processes with synapses. The approach is compatible with standard imaging techniques such as confocal microscopy and permits assessment of the most proximate contacts between astrocytes and neurons in live tissues. In this protocol article we describe the approach to analyze the contacts between striatal astrocyte processes and corticostriatal neuronal projection terminals onto medium spiny neurons. We report the required protocols in detail, including adeno-associated virus microinjections, acute brain slice preparation, imaging, and post hoc FRET quantification. The article provides a detailed description that can be used to characterize and study astrocyte process proximity to synapses in living tissue. © 2020 by John Wiley & Sons, Inc. Basic Protocol 1: Förster resonance energy transfer imaging in cultured cells Basic Protocol 2: Förster resonance energy transfer imaging with the neuron-astrocyte proximity assay in acute brain slices.
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Affiliation(s)
- Aina Badia-Soteras
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, Amsterdam, 1081 HV, The Netherlands
| | - J. Christopher Octeau
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA
| | - Mark H. G. Verheijen
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, Amsterdam, 1081 HV, The Netherlands
| | - Baljit S. Khakh
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA
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10
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Oosterhof N, Kuil LE, van der Linde HC, Burm SM, Berdowski W, van Ijcken WFJ, van Swieten JC, Hol EM, Verheijen MHG, van Ham TJ. Colony-Stimulating Factor 1 Receptor (CSF1R) Regulates Microglia Density and Distribution, but Not Microglia Differentiation In Vivo. Cell Rep 2019; 24:1203-1217.e6. [PMID: 30067976 DOI: 10.1016/j.celrep.2018.06.113] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 05/23/2018] [Accepted: 06/27/2018] [Indexed: 01/02/2023] Open
Abstract
Microglia are brain-resident macrophages with trophic and phagocytic functions. Dominant loss-of-function mutations in a key microglia regulator, colony-stimulating factor 1 receptor (CSF1R), cause adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP), a progressive white matter disorder. Because it remains unclear precisely how CSF1R mutations affect microglia, we generated an allelic series of csf1r mutants in zebrafish to identify csf1r-dependent microglia changes. We found that csf1r mutations led to aberrant microglia density and distribution and regional loss of microglia. The remaining microglia still had a microglia-specific gene expression signature, indicating that they had differentiated normally. Strikingly, we also observed lower microglia numbers and widespread microglia depletion in postmortem brain tissue of ALSP patients. Both in zebrafish and in human disease, local microglia loss also presented in regions without obvious pathology. Together, this implies that CSF1R mainly regulates microglia density and that early loss of microglia may contribute to ALSP pathogenesis.
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Affiliation(s)
- Nynke Oosterhof
- Department of Clinical Genetics, Erasmus MC, University Medical Center Rotterdam, Wytemaweg 80, 3015 CN Rotterdam, the Netherlands
| | - Laura E Kuil
- Department of Clinical Genetics, Erasmus MC, University Medical Center Rotterdam, Wytemaweg 80, 3015 CN Rotterdam, the Netherlands
| | - Herma C van der Linde
- Department of Clinical Genetics, Erasmus MC, University Medical Center Rotterdam, Wytemaweg 80, 3015 CN Rotterdam, the Netherlands
| | - Saskia M Burm
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Woutje Berdowski
- Department of Clinical Genetics, Erasmus MC, University Medical Center Rotterdam, Wytemaweg 80, 3015 CN Rotterdam, the Netherlands
| | - Wilfred F J van Ijcken
- Center for Biomics, Erasmus MC, University Medical Center Rotterdam, Wytemaweg 80, 3015 CN Rotterdam, the Netherlands
| | - John C van Swieten
- Department of Neurology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; Department of Clinical Genetics, VU Medical Center, Amsterdam, the Netherlands
| | - Elly M Hol
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands; Department of Neuroimmunology, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, the Netherlands
| | - Mark H G Verheijen
- Department of Molecular and Cellular Neurobiology, CNCR, Amsterdam Neuroscience, VU University, Amsterdam, the Netherlands
| | - Tjakko J van Ham
- Department of Clinical Genetics, Erasmus MC, University Medical Center Rotterdam, Wytemaweg 80, 3015 CN Rotterdam, the Netherlands.
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11
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van Deijk ALF, Broersen LM, Verkuyl JM, Smit AB, Verheijen MHG. High Content Analysis of Hippocampal Neuron-Astrocyte Co-cultures Shows a Positive Effect of Fortasyn Connect on Neuronal Survival and Postsynaptic Maturation. Front Neurosci 2017; 11:440. [PMID: 28824363 PMCID: PMC5543085 DOI: 10.3389/fnins.2017.00440] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 07/19/2017] [Indexed: 01/01/2023] Open
Abstract
Neuronal and synaptic membranes are composed of a phospholipid bilayer. Supplementation with dietary precursors for phospholipid synthesis –docosahexaenoic acid (DHA), uridine and choline– has been shown to increase neurite outgrowth and synaptogenesis both in vivo and in vitro. A role for multi-nutrient intervention with specific precursors and cofactors has recently emerged in early Alzheimer's disease, which is characterized by decreased synapse numbers in the hippocampus. Moreover, the medical food Souvenaid, containing the specific nutrient combination Fortasyn Connect (FC), improves memory performance in early Alzheimer's disease patients, possibly via maintaining brain connectivity. This suggests an effect of FC on synapses, but the underlying cellular mechanism is not fully understood. Therefore, we investigated the effect of FC (consisting of DHA, eicosapentaenoic acid (EPA), uridine, choline, phospholipids, folic acid, vitamins B12, B6, C and E, and selenium), on synaptogenesis by supplementing it to primary neuron-astrocyte co-cultures, a cellular model that mimics metabolic dependencies in the brain. We measured neuronal developmental processes using high content screening in an automated manner, including neuronal survival, neurite morphology, as well as the formation and maturation of synapses. Here, we show that FC supplementation resulted in increased numbers of neurons without affecting astrocyte number. Furthermore, FC increased postsynaptic PSD95 levels in both immature and mature synapses. These findings suggest that supplementation with FC to neuron-astrocyte co-cultures increased both neuronal survival and the maturation of postsynaptic terminals, which might aid the functional interpretation of FC-based intervention strategies in neurological diseases characterized by neuronal loss and impaired synaptic functioning.
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Affiliation(s)
- Anne-Lieke F van Deijk
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, VU University AmsterdamAmsterdam, Netherlands
| | - Laus M Broersen
- Advanced Medical Nutrition, Nutricia ResearchUtrecht, Netherlands
| | - J Martin Verkuyl
- Advanced Medical Nutrition, Nutricia ResearchUtrecht, Netherlands
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, VU University AmsterdamAmsterdam, Netherlands
| | - Mark H G Verheijen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, VU University AmsterdamAmsterdam, Netherlands
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12
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Camargo N, Goudriaan A, van Deijk ALF, Otte WM, Brouwers JF, Lodder H, Gutmann DH, Nave KA, Dijkhuizen RM, Mansvelder HD, Chrast R, Smit AB, Verheijen MHG. Oligodendroglial myelination requires astrocyte-derived lipids. PLoS Biol 2017; 15:e1002605. [PMID: 28549068 PMCID: PMC5446120 DOI: 10.1371/journal.pbio.1002605] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 04/25/2017] [Indexed: 11/18/2022] Open
Abstract
In the vertebrate nervous system, myelination of axons for rapid impulse propagation requires the synthesis of large amounts of lipids and proteins by oligodendrocytes and Schwann cells. Myelin membranes are thought to be cell-autonomously assembled by these axon-associated glial cells. Here, we report the surprising finding that in normal brain development, a substantial fraction of the lipids incorporated into central nervous system (CNS) myelin are contributed by astrocytes. The oligodendrocyte-specific inactivation of sterol regulatory element-binding protein (SREBP) cleavage-activating protein (SCAP), an essential coactivator of the transcription factor SREBP and thus of lipid biosynthesis, resulted in significantly retarded CNS myelination; however, myelin appeared normal at 3 months of age. Importantly, embryonic deletion of the same gene in astrocytes, or in astrocytes and oligodendrocytes, caused a persistent hypomyelination, as did deletion from astrocytes during postnatal development. Moreover, when astroglial lipid synthesis was inhibited, oligodendrocytes began incorporating circulating lipids into myelin membranes. Indeed, a lipid-enriched diet was sufficient to rescue hypomyelination in these conditional mouse mutants. We conclude that lipid synthesis by oligodendrocytes is heavily supplemented by astrocytes in vivo and that horizontal lipid flux is a major feature of normal brain development and myelination.
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Affiliation(s)
- Nutabi Camargo
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, Amsterdam, the Netherlands
| | - Andrea Goudriaan
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, Amsterdam, the Netherlands
| | - Anne-Lieke F. van Deijk
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, Amsterdam, the Netherlands
| | - Willem M. Otte
- Biomedical MR Imaging and Spectroscopy group, Center for Image Sciences, University Medical Center Utrecht, Utrecht, the Netherlands
- Department of Pediatric Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Jos F. Brouwers
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, the Netherlands
| | - Hans Lodder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, Amsterdam, the Netherlands
| | - David H. Gutmann
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Klaus-Armin Nave
- Max-Planck-Institute of Experimental Medicine, Department of Neurogenetics, Goettingen, Germany
| | - Rick M. Dijkhuizen
- Biomedical MR Imaging and Spectroscopy group, Center for Image Sciences, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Huibert D. Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, Amsterdam, the Netherlands
| | - Roman Chrast
- Department of Neuroscience and Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - August B. Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, Amsterdam, the Netherlands
| | - Mark H. G. Verheijen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, Amsterdam, the Netherlands
- * E-mail:
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13
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van Deijk ALF, Camargo N, Timmerman J, Heistek T, Brouwers JF, Mogavero F, Mansvelder HD, Smit AB, Verheijen MHG. Astrocyte lipid metabolism is critical for synapse development and function in vivo. Glia 2017; 65:670-682. [PMID: 28168742 DOI: 10.1002/glia.23120] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 01/08/2017] [Accepted: 01/10/2017] [Indexed: 12/21/2022]
Abstract
The brain is considered to be autonomous in lipid synthesis with astrocytes producing lipids far more efficiently than neurons. Accordingly, it is generally assumed that astrocyte-derived lipids are taken up by neurons to support synapse formation and function. Initial confirmation of this assumption has been obtained in cell cultures, but whether astrocyte-derived lipids support synapses in vivo is not known. Here, we address this issue and determined the role of astrocyte lipid metabolism in hippocampal synapse formation and function in vivo. Hippocampal protein expression for the sterol regulatory element-binding protein (SREBP) and its target gene fatty acid synthase (Fasn) was found in astrocytes but not in neurons. Diminishing SREBP activity in astrocytes using mice in which the SREBP cleavage-activating protein (SCAP) was deleted from GFAP-expressing cells resulted in decreased cholesterol and phospholipid secretion by astrocytes. Interestingly, SCAP mutant mice showed more immature synapses, lower presynaptic protein SNAP-25 levels as well as reduced numbers of synaptic vesicles, indicating impaired development of the presynaptic terminal. Accordingly, hippocampal short-term and long-term synaptic plasticity were defective in mutant mice. These findings establish a critical role for astrocyte lipid metabolism in presynaptic terminal development and function in vivo. GLIA 2017;65:670-682.
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Affiliation(s)
- Anne-Lieke F van Deijk
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, De Boelelaan 1085, Amsterdam, 1081 HV, The Netherlands
| | - Nutabi Camargo
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, De Boelelaan 1085, Amsterdam, 1081 HV, The Netherlands
| | - Jaap Timmerman
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, De Boelelaan 1085, Amsterdam, 1081 HV, The Netherlands
| | - Tim Heistek
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, De Boelelaan 1085, Amsterdam, 1081 HV, The Netherlands
| | - Jos F Brouwers
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Yalelaan 1, 3584 CL Utrecht University, Utrecht, The Netherlands
| | - Floriana Mogavero
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, De Boelelaan 1085, Amsterdam, 1081 HV, The Netherlands
| | - Huibert D Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, De Boelelaan 1085, Amsterdam, 1081 HV, The Netherlands
| | - August B Smit
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, De Boelelaan 1085, Amsterdam, 1081 HV, The Netherlands
| | - Mark H G Verheijen
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, De Boelelaan 1085, Amsterdam, 1081 HV, The Netherlands
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14
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Chavarria-Siles I, White T, de Leeuw C, Goudriaan A, Lips E, Ehrlich S, Turner JA, Calhoun VD, Gollub RL, Magnotta VA, Ho BC, Smit AB, Verheijen MHG, Posthuma D. Myelination-related genes are associated with decreased white matter integrity in schizophrenia. Eur J Hum Genet 2015; 24:381-6. [PMID: 26014434 DOI: 10.1038/ejhg.2015.120] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 03/24/2015] [Accepted: 04/17/2015] [Indexed: 01/01/2023] Open
Abstract
Disruptions in white matter (WM) tract structures have been implicated consistently in the pathophysiology of schizophrenia. Global WM integrity--as measured by fractional anisotropy (FA)--is highly heritable and may provide a good endophenotype for genetic studies of schizophrenia. WM abnormalities in schizophrenia are not localized to one specific brain region but instead reflect global low-level decreases in FA coupled with focal abnormalities. In this study, we sought to investigate whether functional gene sets associated with schizophrenia are also associated with WM integrity. We analyzed FA and genetic data from the Mind Research Network Clinical Imaging Consortium to study the effect of multiple oligodendrocyte gene sets on schizophrenia and WM integrity using a functional gene set analysis in 77 subjects with schizophrenia and 104 healthy controls. We found that a gene set involved in myelination was significantly associated with schizophrenia and FA. This gene set includes 17 genes that are expressed in oligodendrocytes and one neuronal gene (NRG1) that is known to regulate myelination. None of the genes within the gene set were associated with schizophrenia or FA individually, suggesting that no single gene was driving the association of the gene set. Our findings support the hypothesis that multiple genetic variants in myelination-related genes contribute to the observed correlation between schizophrenia and decreased WM integrity as measured by FA.
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Affiliation(s)
- Ivan Chavarria-Siles
- Department of Functional Genomics, CNCR, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands.,Department of Complex Trait Genetics, VU University Medical Center, Amsterdam, The Netherlands.,Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Tonya White
- Department of Child and Adolescent Psychiatry, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Radiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Christiaan de Leeuw
- Department of Functional Genomics, CNCR, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands.,Department of Complex Trait Genetics, VU University Medical Center, Amsterdam, The Netherlands
| | - Andrea Goudriaan
- Department of Molecular and Cellular Neurobiology, CNCR, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Esther Lips
- Department of Functional Genomics, CNCR, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Stefan Ehrlich
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, USA.,Department of Child and Adolescent Psychiatry, TU Dresden, Germany
| | - Jessica A Turner
- Department of Psychology and Neuroscience Institute, Georgia State University, Atlanta, GA, USA.,The Mind Research Network, Albuquerque, NM, USA
| | - Vince D Calhoun
- The Mind Research Network, Albuquerque, NM, USA.,Department of Psychiatry, University of New Mexico, New Mexico, NM, USA.,Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, NM, USA
| | - Randy L Gollub
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, USA.,Departments of Psychiatry and Radiology, Massachusetts General Hospital, Boston, MA, USA
| | - Vincent A Magnotta
- Department of Radiology, The University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Beng-Choon Ho
- Department of Psychiatry, The University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, CNCR, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Mark H G Verheijen
- Department of Molecular and Cellular Neurobiology, CNCR, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Danielle Posthuma
- Department of Functional Genomics, CNCR, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands.,Department of Complex Trait Genetics, VU University Medical Center, Amsterdam, The Netherlands.,Department of Child and Adolescent Psychiatry, Erasmus Medical Center, Rotterdam, The Netherlands
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15
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Rao-Ruiz P, Carney KE, Pandya N, van der Loo RJ, Verheijen MHG, van Nierop P, Smit AB, Spijker S. Time-dependent changes in the mouse hippocampal synaptic membrane proteome after contextual fear conditioning. Hippocampus 2015; 25:1250-61. [PMID: 25708624 DOI: 10.1002/hipo.22432] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2015] [Indexed: 01/15/2023]
Abstract
A change in efficacy of hippocampal synapses is critical for memory formation. So far, the molecular analysis of synapses during learning has focused on small groups of proteins, whereas the dynamic global changes at these synapses have remained unknown. Here, we analyzed the temporal changes of the mouse hippocampal synaptic membrane proteome 1 and 4 h after contextual fear learning, comparing two groups; (1) a fear memory forming "delayed-shock" group and (2) a fear memory-deficient "immediate-shock" group. No changes in protein expression were observed 1 h after conditioning between the two experimental groups. However, 423 proteins were significantly regulated 4 h later of which 164 proteins showed a temporal regulation after a delayed shock and 273 proteins after the stress of an immediate shock. From the proteins that were differentially regulated between the delayed- and the immediate-shock groups at 4 h, 48 proteins, most prominently representing endocytosis, (amphiphysin, dynamin, and synaptojanin1), glutamate signaling (glutamate [NMDA] receptor subunit epsilon-1, disks large homolog 3), and neurotransmitter metabolism (excitatory amino acid transporter 1, excitatory amino acid transporter 2, sodium- and chloride-dependent GABA transporter 3) were regulated in both protocols, but in opposite directions, pointing toward an interaction of learning and stress. Taken together, this data set yields novel insight into diverse and dynamic changes that take place at hippocampal synapses over the time course of contextual fear-memory learning.
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Affiliation(s)
- Priyanka Rao-Ruiz
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Karen E Carney
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands.,INSERM U862, Neurocentre Magendie, Bordeaux, France.,Université De Bordeaux, Bordeaux, France
| | - Nikhil Pandya
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Rolinka J van der Loo
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Mark H G Verheijen
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Pim van Nierop
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - August B Smit
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Sabine Spijker
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
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16
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de Leeuw C, Goudriaan A, Smit AB, Yu D, Mathews CA, Scharf JM, Verheijen MHG, Posthuma D. Involvement of astrocyte metabolic coupling in Tourette syndrome pathogenesis. Eur J Hum Genet 2015; 23:1519-22. [PMID: 25735483 DOI: 10.1038/ejhg.2015.22] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 12/11/2014] [Accepted: 01/20/2015] [Indexed: 01/02/2023] Open
Abstract
Tourette syndrome is a heritable neurodevelopmental disorder whose pathophysiology remains unknown. Recent genome-wide association studies suggest that it is a polygenic disorder influenced by many genes of small effect. We tested whether these genes cluster in cellular function by applying gene-set analysis using expert curated sets of brain-expressed genes in the current largest available Tourette syndrome genome-wide association data set, involving 1285 cases and 4964 controls. The gene sets included specific synaptic, astrocytic, oligodendrocyte and microglial functions. We report association of Tourette syndrome with a set of genes involved in astrocyte function, specifically in astrocyte carbohydrate metabolism. This association is driven primarily by a subset of 33 genes involved in glycolysis and glutamate metabolism through which astrocytes support synaptic function. Our results indicate for the first time that the process of astrocyte-neuron metabolic coupling may be an important contributor to Tourette syndrome pathogenesis.
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Affiliation(s)
- Christiaan de Leeuw
- Department of Complex Trait Genetics, VU University Medical Center, Amsterdam, The Netherlands.,Institute for Computing and Information Sciences, Radboud University, Nijmegen, The Netherlands
| | - Andrea Goudriaan
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Dongmei Yu
- Psychiatric and Neurodevelopmental Genetics Unit, Departments of Psychiatry and Neurology, Center for Human Genetics Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Carol A Mathews
- Department of Psychiatry, Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Jeremiah M Scharf
- Psychiatric and Neurodevelopmental Genetics Unit, Departments of Psychiatry and Neurology, Center for Human Genetics Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.,Division of Cognitive and Behavioral Neurology, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Mark H G Verheijen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Danielle Posthuma
- Department of Complex Trait Genetics, VU University Medical Center, Amsterdam, The Netherlands.,Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands.,Department of Child and Adolescent Psychiatry, Erasmus University Rotterdam, Sophia Child Hospital, Rotterdam, The Netherlands
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17
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Carney KE, Milanese M, van Nierop P, Li KW, Oliet SHR, Smit AB, Bonanno G, Verheijen MHG. Proteomic analysis of gliosomes from mouse brain: identification and investigation of glial membrane proteins. J Proteome Res 2014; 13:5918-27. [PMID: 25308431 DOI: 10.1021/pr500829z] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Astrocytes are being increasingly recognized as crucial contributors to neuronal function at synapses, axons, and somas. Reliable methods that can provide insight into astrocyte proteins at the neuron-astrocyte functional interface are highly desirable. Here, we conducted a mass spectrometry analysis of Percoll gradient-isolated gliosomes, a viable preparation of glial subcellular particles often used to study mechanisms of astrocytic transmitter uptake and release and their regulation. Gliosomes were compared with synaptosomes, a preparation containing the neurotransmitter release machinery, and, accordingly, synaptosomes were enriched for proteins involved in synaptic vesicle-mediated transport. Interestingly, gliosome preparations were found to be enriched for different classes of known astrocyte proteins, such as VAMP3 (involved in astrocyte exocytosis), Ezrin (perisynaptic astrocyte cytoskeletal protein), and Basigin (astrocyte membrane glycoprotein), as well as for G-protein-mediated signaling proteins. Mass spectrometry data are available via ProteomeXchange with the identifier PXD001375. Together, these data provide the first detailed description of the gliosome proteome and show that gliosomes can be a useful preparation to study glial membrane proteins and associated processes.
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Affiliation(s)
- Karen E Carney
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam , 1081 HV Amsterdam, The Netherlands
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18
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Norrmén C, Figlia G, Lebrun-Julien F, Pereira JA, Trötzmüller M, Köfeler HC, Rantanen V, Wessig C, van Deijk ALF, Smit AB, Verheijen MHG, Rüegg MA, Hall MN, Suter U. mTORC1 controls PNS myelination along the mTORC1-RXRγ-SREBP-lipid biosynthesis axis in Schwann cells. Cell Rep 2014; 9:646-60. [PMID: 25310982 DOI: 10.1016/j.celrep.2014.09.001] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Revised: 04/05/2014] [Accepted: 08/28/2014] [Indexed: 11/26/2022] Open
Abstract
Myelin formation during peripheral nervous system (PNS) development, and reformation after injury and in disease, requires multiple intrinsic and extrinsic signals. Akt/mTOR signaling has emerged as a major player involved, but the molecular mechanisms and downstream effectors are virtually unknown. Here, we have used Schwann-cell-specific conditional gene ablation of raptor and rictor, which encode essential components of the mTOR complexes 1 (mTORC1) and 2 (mTORC2), respectively, to demonstrate that mTORC1 controls PNS myelination during development. In this process, mTORC1 regulates lipid biosynthesis via sterol regulatory element-binding proteins (SREBPs). This course of action is mediated by the nuclear receptor RXRγ, which transcriptionally regulates SREBP1c downstream of mTORC1. Absence of mTORC1 causes delayed myelination initiation as well as hypomyelination, together with abnormal lipid composition and decreased nerve conduction velocity. Thus, we have identified the mTORC1-RXRγ-SREBP axis controlling lipid biosynthesis as a major contributor to proper peripheral nerve function.
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Affiliation(s)
- Camilla Norrmén
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology Zurich, ETH Zürich, CH-8093 Zurich, Switzerland.
| | - Gianluca Figlia
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology Zurich, ETH Zürich, CH-8093 Zurich, Switzerland
| | - Frédéric Lebrun-Julien
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology Zurich, ETH Zürich, CH-8093 Zurich, Switzerland
| | - Jorge A Pereira
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology Zurich, ETH Zürich, CH-8093 Zurich, Switzerland
| | - Martin Trötzmüller
- Core Facility for Mass Spectrometry, Center for Medical Research, Medical University of Graz, 8010 Graz, Austria
| | - Harald C Köfeler
- Core Facility for Mass Spectrometry, Center for Medical Research, Medical University of Graz, 8010 Graz, Austria
| | - Ville Rantanen
- Research Programs Unit, Genome-Scale Biology, and Institute of Biomedicine, Biochemistry and Developmental Biology, University of Helsinki, 00014 Helsinki, Finland
| | - Carsten Wessig
- Department of Neurology, University of Würzburg, 97080 Würzburg, Germany
| | - Anne-Lieke F van Deijk
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, 1081HV Amsterdam, the Netherlands
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, 1081HV Amsterdam, the Netherlands
| | - Mark H G Verheijen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, 1081HV Amsterdam, the Netherlands
| | - Markus A Rüegg
- Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Michael N Hall
- Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Ueli Suter
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology Zurich, ETH Zürich, CH-8093 Zurich, Switzerland.
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Goudriaan A, de Leeuw C, Ripke S, Hultman CM, Sklar P, Sullivan PF, Smit AB, Posthuma D, Verheijen MHG. Specific glial functions contribute to schizophrenia susceptibility. Schizophr Bull 2014; 40:925-35. [PMID: 23956119 PMCID: PMC4059439 DOI: 10.1093/schbul/sbt109] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Schizophrenia is a highly polygenic brain disorder. The main hypothesis for disease etiology in schizophrenia primarily focuses on the role of dysfunctional synaptic transmission. Previous studies have therefore directed their investigations toward the role of neuronal dysfunction. However, recent studies have shown that apart from neurons, glial cells also play a major role in synaptic transmission. Therefore, we investigated the potential causal involvement of the 3 principle glial cell lineages in risk to schizophrenia. We performed a functional gene set analysis to test for the combined effects of genetic variants in glial type-specific genes for association with schizophrenia. We used genome-wide association data from the largest schizophrenia sample to date, including 13 689 cases and 18 226 healthy controls. Our results show that astrocyte and oligodendrocyte gene sets, but not microglia gene sets, are associated with an increased risk for schizophrenia. The astrocyte and oligodendrocyte findings are related to astrocyte signaling at the synapse, myelin membrane integrity, glial development, and epigenetic control. Together, these results show that genetic alterations underlying specific glial cell type functions increase susceptibility to schizophrenia and provide evidence that the neuronal hypothesis of schizophrenia should be extended to include the role of glia.
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Affiliation(s)
- Andrea Goudriaan
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, the Netherlands;
| | - Christiaan de Leeuw
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, the Netherlands; Institute for Computing and Information Sciences, Radboud University, Nijmegen, the Netherlands
| | - Stephan Ripke
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA; Stanley Center for Psychiatric Research, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA
| | - Christina M Hultman
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Pamela Sklar
- Department of Psychiatry, Mount Sinai School of Medicine, New York, NY
| | - Patrick F Sullivan
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden; Center for Psychiatric Genomics, Department of Genetics, University of North Carolina, Chapel Hill, NC
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, the Netherlands
| | - Danielle Posthuma
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, the Netherlands;
| | - Mark H G Verheijen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, the Netherlands
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20
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Zenker J, Stettner M, Ruskamo S, Domènech-Estévez E, Baloui H, Médard JJ, Verheijen MHG, Brouwers JF, Kursula P, Kieseier BC, Chrast R. A role of peripheral myelin protein 2 in lipid homeostasis of myelinating Schwann cells. Glia 2014; 62:1502-12. [PMID: 24849898 DOI: 10.1002/glia.22696] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 05/06/2014] [Accepted: 05/07/2014] [Indexed: 01/28/2023]
Abstract
Peripheral myelin protein 2 (Pmp2, P2 or Fabp8), a member of the fatty acid binding protein family, was originally described together with myelin basic protein (Mbp or P1) and myelin protein zero (Mpz or P0) as one of the most abundant myelin proteins in the peripheral nervous system (PNS). Although Pmp2 is predominantly expressed in myelinated Schwann cells, its role in glia is currently unknown. To study its function in PNS biology, we have generated a complete Pmp2 knockout mouse (Pmp2(-/-) ). Comprehensive characterization of Pmp2(-/-) mice revealed a temporary reduction in their motor nerve conduction velocity (MNCV). While this change was not accompanied by any defects in general myelin structure, we detected transitory alterations in the myelin lipid profile of Pmp2(-/-) mice. It was previously proposed that Pmp2 and Mbp have comparable functions in the PNS suggesting that the presence of Mbp can partially mask the Pmp2(-/-) phenotype. Indeed, we found that Mbp lacking Shi(-/-) mice, similar to Pmp2(-/-) animals, have preserved myelin structure and reduced MNCV, but this phenotype was not aggravated in Pmp2(-/-) /Shi(-/-) mutants indicating that Pmp2 and Mbp do not substitute each other's functions in the PNS. These data, together with our observation that Pmp2 binds and transports fatty acids to membranes, uncover a role for Pmp2 in lipid homeostasis of myelinating Schwann cells.
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Affiliation(s)
- Jennifer Zenker
- Department of Medical Genetics, University of Lausanne, Switzerland; Graduate Program in Neurosciences, University of Lausanne, Switzerland
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Goudriaan A, Camargo N, Carney KE, Oliet SHR, Smit AB, Verheijen MHG. Novel cell separation method for molecular analysis of neuron-astrocyte co-cultures. Front Cell Neurosci 2014; 8:12. [PMID: 24523672 PMCID: PMC3906515 DOI: 10.3389/fncel.2014.00012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 01/08/2014] [Indexed: 11/15/2022] Open
Abstract
Over the last decade, the importance of astrocyte-neuron communication in neuronal development and synaptic plasticity has become increasingly clear. Since neuron-astrocyte interactions represent highly dynamic and reciprocal processes, we hypothesized that many astrocyte genes may be regulated as a consequence of their interactions with maturing neurons. In order to identify such neuron-responsive astrocyte genes in vitro, we sought to establish an expedited technique for separation of neurons from co-cultured astrocytes. Our newly established method makes use of cold jet, which exploits different adhesion characteristics of subpopulations of cells (Jirsova etal., 1997), and is rapid, performed under ice-cold conditions and avoids protease-mediated isolation of astrocytes or time-consuming centrifugation, yielding intact astrocyte mRNA with approximately 90% of neuronal RNA removed. Using this purification method, we executed genome-wide profiling in which RNA derived from astrocyte-only cultures was compared with astrocyte RNA derived from differentiating neuron-astrocyte co-cultures. Data analysis determined that many astrocytic mRNAs and biological processes are regulated by neuronal interaction. Our results validate the cold jet as an efficient method to separate astrocytes from neurons in co-culture, and reveals that neurons induce robust gene-expression changes in co-cultured astrocytes.
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Affiliation(s)
- Andrea Goudriaan
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam Amsterdam, Netherlands
| | - Nutabi Camargo
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam Amsterdam, Netherlands
| | - Karen E Carney
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam Amsterdam, Netherlands ; INSERM U862, Neurocentre Magendie Bordeaux, France ; Université de Bordeaux Bordeaux, France
| | - Stéphane H R Oliet
- INSERM U862, Neurocentre Magendie Bordeaux, France ; Université de Bordeaux Bordeaux, France
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam Amsterdam, Netherlands
| | - Mark H G Verheijen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam Amsterdam, Netherlands
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22
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Verheijen MHG, Peviani M, Hendricusdottir R, Bell EM, Lammens M, Smit AB, Bendotti C, van Minnen J. Increased axonal ribosome numbers is an early event in the pathogenesis of amyotrophic lateral sclerosis. PLoS One 2014; 9:e87255. [PMID: 24498056 PMCID: PMC3907527 DOI: 10.1371/journal.pone.0087255] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 12/24/2013] [Indexed: 12/14/2022] Open
Abstract
Myelinating glia cells support axon survival and functions through mechanisms independent of myelination, and their dysfunction leads to axonal degeneration in several diseases. In amyotrophic lateral sclerosis (ALS), spinal motor neurons undergo retrograde degeneration, and slowing of axonal transport is an early event that in ALS mutant mice occurs well before motor neuron degeneration. Interestingly, in familial forms of ALS, Schwann cells have been proposed to slow disease progression. We demonstrated previously that Schwann cells transfer polyribosomes to diseased and regenerating axons, a possible rescue mechanism for disease-induced reductions in axonal proteins. Here, we investigated whether elevated levels of axonal ribosomes are also found in ALS, by analysis of a superoxide dismutase 1 (SOD1)G93A mouse model for human familial ALS and a patient suffering from sporadic ALS. In both cases, we found that the disorder was associated with an increase in the population of axonal ribosomes in myelinated axons. Importantly, in SOD1G93A mice, the appearance of axonal ribosomes preceded the manifestation of behavioral symptoms, indicating that upregulation of axonal ribosomes occurs early in the pathogenesis of ALS. In line with our previous studies, electron microscopy analysis showed that Schwann cells might serve as a source of axonal ribosomes in the disease-compromised axons. The early appearance of axonal ribosomes indicates an involvement of Schwann cells early in ALS neuropathology, and may serve as an early marker for disease-affected axons, not only in ALS, but also for other central and peripheral neurodegenerative disorders.
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Affiliation(s)
- Mark H. G. Verheijen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Marco Peviani
- Laboratory of Molecular Neurobiology, Department of Neuroscience, “Mario Negri” Institute for Pharmacological Research, Milan, Italy
| | - Rita Hendricusdottir
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Erin M. Bell
- Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - Martin Lammens
- Department of Pathology, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium
| | - August B. Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Caterina Bendotti
- Laboratory of Molecular Neurobiology, Department of Neuroscience, “Mario Negri” Institute for Pharmacological Research, Milan, Italy
| | - Jan van Minnen
- Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
- * E-mail:
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Nadra K, Médard JJ, Quignodon L, Verheijen MHG, Desvergne B, Chrast R. Epineurial adipocytes are dispensable for Schwann cell myelination. J Neurochem 2012; 123:662-7. [PMID: 22849425 DOI: 10.1111/j.1471-4159.2012.07896.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 07/11/2012] [Accepted: 07/12/2012] [Indexed: 12/18/2022]
Abstract
Previous clinical observations and data from mouse models with defects in lipid metabolism suggested that epineurial adipocytes may play a role in peripheral nervous system myelination. We have used adipocyte-specific Lpin1 knockout mice to characterize the consequences of the presence of impaired epineurial adipocytes on the myelinating peripheral nerve. Our data revealed that the capacity of Schwann cells to establish myelin, and the functional properties of peripheral nerves, were not affected by compromised epineurial adipocytes in adipocyte-specific Lpin1 knockout mice. To evaluate the possibility that Lpin1-negative adipocytes are still able to support endoneurial Schwann cells, we also characterized sciatic nerves from mice carrying epiblast-specific deletion of peroxisome proliferator-activated receptor gamma, which develop general lipoatrophy. Interestingly, even the complete loss of adipocytes in the epineurium of peroxisome proliferator-activated receptor gamma knockout mice did not lead to detectable defects in Schwann cell myelination. However, probably as a consequence of their hyperglycemia, these mice have reduced nerve conduction velocity, thus mimicking the phenotype observed under diabetic condition. Together, our data indicate that while adipocytes, as regulators of lipid and glucose homeostasis, play a role in nerve function, their presence in epineurium is not essential for establishment or maintenance of proper myelin.
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Affiliation(s)
- Karim Nadra
- Department of Medical Genetics, University of Lausanne, Lausanne, Switzerland
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24
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Camargo N, Brouwers JF, Loos M, Gutmann DH, Smit AB, Verheijen MHG. High-fat diet ameliorates neurological deficits caused by defective astrocyte lipid metabolism. FASEB J 2012; 26:4302-15. [PMID: 22751013 DOI: 10.1096/fj.12-205807] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The mammalian CNS is considered to be autonomous in lipid metabolism. Glial cells, in particular astrocytes, have been shown to be highly active in lipid synthesis and secretion. To determine the importance of astrocytes as lipid providers in the brain, we generated mice in which the sterol regulatory element-binding protein (SREBP) cleavage-activating protein (SCAP) was deleted from astrocytes using cre/lox technology. SCAP mutant mice showed microcephaly, without effects on astrocyte survival. SCAP deletion in astrocytes led to a loss of cholesterol and fatty acid synthesis pathways. SCAP mutants showed progressive motor deficits, dyskinesia, and reduced anxiety. Interestingly, SCAP mutants showed changes in brain sterol and fatty acid profiles that were concordant with reduced lipid synthesis as well as with increased uptake of dietary lipids. Accordingly, a high-fat diet rich in cholesterol and monounsaturated fatty acids, but not a fish oil diet rich in polyunsaturated fatty acids, improved motor deficits and survival of the mutant mice. These observations establish a critical role for astrocytes in brain lipid metabolism and demonstrate that dietary lipids can rescue astrocyte-mediated lipid deficiency. The ability to correct these neurological deficits suggests that lipid supplementation may serve as a treatment for brain disorders associated with defective astrocyte lipid synthesis.
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Affiliation(s)
- Nutabi Camargo
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, De Boelelaan 1081HV, Amsterdam, The Netherlands
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25
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Verdier V, Csárdi G, de Preux-Charles AS, Médard JJ, Smit AB, Verheijen MHG, Bergmann S, Chrast R. Aging of myelinating glial cells predominantly affects lipid metabolism and immune response pathways. Glia 2012; 60:751-60. [PMID: 22337502 DOI: 10.1002/glia.22305] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 01/19/2012] [Indexed: 01/17/2023]
Abstract
Both the central and the peripheral nervous systems are prone to multiple age-dependent neurological deficits, often attributed to still unknown alterations in the function of myelinating glia. To uncover the biological processes affected in glial cells by aging, we analyzed gene expression of the Schwann cell-rich mouse sciatic nerve at 17 time points throughout life, from day of birth until senescence. By combining these data with the gene expression data of myelin mouse mutants carrying deletions of either Pmp22, SCAP, or Lpin1, we found that the majority of age-related transcripts were also affected in myelin mutants (54.4%) and were regulated during PNS development (59.5%), indicating a high level of overlap in implicated molecular pathways. The expression profiles in aging copied the direction of transcriptional changes observed in neuropathy models; however, they had the opposite direction when compared with PNS development. The most significantly altered biological processes in aging involved the inflammatory/immune response and lipid metabolism. Interestingly, both these pathways were comparably changed in the aging optic nerve, suggesting that similar biological processes are affected in aging of glia-rich parts of the central and peripheral nervous systems. Our comprehensive comparison of gene expression in three distinct biological conditions including development, aging, and myelin disease thus revealed a previously unanticipated relationship among themselves and identified lipid metabolism and inflammatory/immune response pathways as potential therapeutical targets to prevent or delay so far incurable age-related and inherited forms of neuropathies.
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Affiliation(s)
- Valérie Verdier
- Department of Medical Genetics, University of Lausanne, Lausanne, Switzerland
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26
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Verheijen MHG, Lammens M, Ceuterick-de Groote C, Timmerman V, De Jonghe P, King RHM, Smit AB, van Minnen J. Increased axonal ribosome numbers in CMT diseases. J Peripher Nerv Syst 2011; 16:71-3. [DOI: 10.1111/j.1529-8027.2011.00322.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Chrast R, Saher G, Nave KA, Verheijen MHG. Lipid metabolism in myelinating glial cells: lessons from human inherited disorders and mouse models. J Lipid Res 2010; 52:419-34. [PMID: 21062955 DOI: 10.1194/jlr.r009761] [Citation(s) in RCA: 197] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The integrity of central and peripheral nervous system myelin is affected in numerous lipid metabolism disorders. This vulnerability was so far mostly attributed to the extraordinarily high level of lipid synthesis that is required for the formation of myelin, and to the relative autonomy in lipid synthesis of myelinating glial cells because of blood barriers shielding the nervous system from circulating lipids. Recent insights from analysis of inherited lipid disorders, especially those with prevailing lipid depletion and from mouse models with glia-specific disruption of lipid metabolism, shed new light on this issue. The particular lipid composition of myelin, the transport of lipid-associated myelin proteins, and the necessity for timely assembly of the myelin sheath all contribute to the observed vulnerability of myelin to perturbed lipid metabolism. Furthermore, the uptake of external lipids may also play a role in the formation of myelin membranes. In addition to an improved understanding of basic myelin biology, these data provide a foundation for future therapeutic interventions aiming at preserving glial cell integrity in metabolic disorders.
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Affiliation(s)
- Roman Chrast
- Department of Medical Genetics, University of Lausanne, Switzerland.
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29
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de Preux AS, Goosen K, Zhang W, Sima AAF, Shimano H, Ouwens DM, Diamant M, Hillebrands JL, Rozing J, Lemke G, Beckmann JS, Smit AB, Verheijen MHG, Chrast R. SREBP-1c expression in Schwann cells is affected by diabetes and nutritional status. Mol Cell Neurosci 2007; 35:525-34. [PMID: 17632011 DOI: 10.1016/j.mcn.2007.04.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2007] [Accepted: 04/24/2007] [Indexed: 02/02/2023] Open
Abstract
Our previous work demonstrated that the sterol response element binding proteins (SREBP)-1 and SREBP-2, which are the key regulators of storage lipid and cholesterol metabolism respectively, are highly expressed in Schwann cells of adult peripheral nerves. In order to evaluate the role of Schwann cell SREBPs in myelination and functioning of peripheral nerves we have determined their expression during development, after fasting and refeeding, and in a rodent model of diabetes. Our results show that SREBP-1c and SREBP-2, unlike SREBP-1a, are the major forms of SREBPs present in peripheral nerves. The expression profile of SREBP-2 follows the expression of genes involved in cholesterol biosynthesis, while SREBP-1c is co-expressed with genes involved in storage lipid metabolism. In addition, the expression of SREBP-1c in the endoneurial compartment of peripheral nerves depends on nutritional status and is disturbed in type 1 diabetes. In line with this, insulin elevates the expression of SREBP-1c in primary cultured Schwann cells by activating the SREBP-1c promoter. Taken together, these findings reveal that SREBP-1c expression in Schwann cells responds to metabolic stimuli including insulin and that this response is affected in type 1 diabetes mellitus. This suggests that disturbed SREBP-1c regulated lipid metabolism may contribute to the pathophysiology of diabetic peripheral neuropathy.
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30
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Pellis-van Berkel W, Verheijen MHG, Cuppen E, Asahina M, de Rooij J, Jansen G, Plasterk RHA, Bos JL, Zwartkruis FJT. Requirement of the Caenorhabditis elegans RapGEF pxf-1 and rap-1 for epithelial integrity. Mol Biol Cell 2004; 16:106-16. [PMID: 15525675 PMCID: PMC539156 DOI: 10.1091/mbc.e04-06-0492] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The Rap-pathway has been implicated in various cellular processes but its exact physiological function remains poorly defined. Here we show that the Caenorhabditis elegans homologue of the mammalian guanine nucleotide exchange factors PDZ-GEFs, PXF-1, specifically activates Rap1 and Rap2. Green fluorescent protein (GFP) reporter constructs demonstrate that sites of pxf-1 expression include the hypodermis and gut. Particularly striking is the oscillating expression of pxf-1 in the pharynx during the four larval molts. Deletion of the catalytic domain from pxf-1 leads to hypodermal defects, resulting in lethality. The cuticle secreted by pxf-1 mutants is disorganized and can often not be shed during molting. At later stages, hypodermal degeneration is seen and animals that reach adulthood frequently die with a burst vulva phenotype. Importantly, disruption of rap-1 leads to a similar, but less severe phenotype, which is enhanced by the simultaneous removal of rap-2. In addition, the lethal phenotype of pxf-1 can be rescued by expression of an activated version of rap-1. Together these results demonstrate that the pxf-1/rap pathway in C. elegans is required for maintenance of epithelial integrity, in which it probably functions in polarized secretion.
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Affiliation(s)
- W Pellis-van Berkel
- Department of Physiological Chemistry and Centre for Biomedical Genetics, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands
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31
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Chrast R, Verheijen MHG, Lemke G. Complement factors in adult peripheral nerve: a potential role in energy metabolism. Neurochem Int 2004; 45:353-9. [PMID: 15145549 DOI: 10.1016/j.neuint.2003.09.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2003] [Revised: 09/18/2003] [Accepted: 09/23/2003] [Indexed: 10/26/2022]
Abstract
Complement cascade factors are known to play a critical role in myelin clearance after peripheral nerve injury. Here we show that components of both the classical (C1qa, C1qb, C1qc, C2 and C4) and alternative (C3, B and adipsin) pathways are expressed by uninjured peripheral nerve as well. mRNAs of components of the alternative pathway were predominantly found in the peri/epineurium, although factor C3 and factor B were also detected in the endoneurial compartment of adult nerve. Interestingly, adipsin mRNA was detected only in peri/epineurium, while adipsin protein was present in both peri/epineurium and endoneurium. This suggests that adipsin is transported to the endoneurium via the circulation from the peri/epineurium or outside of the nerve. Factor 5 and factor 9, necessary for the formation of the membrane-attack complex, were not detected in any part of the healthy peripheral nerve, which together with the observed presence of negative regulators of complement activation, is likely to prevent damage to the healthy nerve caused by complement activation. By analogy with the known role of complement factors in fat, we propose that local expression of these factors plays a role in the regulation of fatty acid homeostasis in the nerve and, thereby, in energy metabolism cross-talk between different compartments of the peripheral nerve.
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Affiliation(s)
- Roman Chrast
- Molecular Neurobiology Laboratory, The Salk Institute, 10010 N. Torrey Pines Rd., La Jolla, CA 92037, USA
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Senderek J, Bergmann C, Stendel C, Kirfel J, Verpoorten N, De Jonghe P, Timmerman V, Chrast R, Verheijen MHG, Lemke G, Battaloglu E, Parman Y, Erdem S, Tan E, Topaloglu H, Hahn A, Müller-Felber W, Rizzuto N, Fabrizi GM, Stuhrmann M, Rudnik-Schöneborn S, Züchner S, Michael Schröder J, Buchheim E, Straub V, Klepper J, Huehne K, Rautenstrauss B, Büttner R, Nelis E, Zerres K. Mutations in a gene encoding a novel SH3/TPR domain protein cause autosomal recessive Charcot-Marie-Tooth type 4C neuropathy. Am J Hum Genet 2003; 73:1106-19. [PMID: 14574644 PMCID: PMC1180490 DOI: 10.1086/379525] [Citation(s) in RCA: 156] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2003] [Accepted: 08/26/2003] [Indexed: 01/30/2023] Open
Abstract
Charcot-Marie-Tooth disease type 4C (CMT4C) is a childhood-onset demyelinating form of hereditary motor and sensory neuropathy associated with an early-onset scoliosis and a distinct Schwann cell pathology. CMT4C is inherited as an autosomal recessive trait and has been mapped to a 13-cM linkage interval on chromosome 5q23-q33. By homozygosity mapping and allele-sharing analysis, we refined the CMT4C locus to a suggestive critical region of 1.7 Mb. We subsequently identified mutations in an uncharacterized transcript, KIAA1985, in 12 families with autosomal recessive neuropathy. We observed eight distinct protein-truncating mutations and three nonconservative missense mutations affecting amino acids conserved through evolution. In all families, we identified a mutation on each disease allele, either in the homozygous or in the compound heterozygous state. The CMT4C gene is strongly expressed in neural tissues, including peripheral nerve tissue. The translated protein defines a new protein family of unknown function with putative orthologues in vertebrates. Comparative sequence alignments indicate that members of this protein family contain multiple SH3 and TPR domains that are likely involved in the formation of protein complexes.
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Affiliation(s)
- Jan Senderek
- Department of Human Genetics, Aachen University of Technology, Aachen, Germany.
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Abstract
We comprehensively analyzed gene expression during peripheral nerve development by performing microarray analyses of premyelinating, myelinating, and postmyelinating mouse sciatic nerves, and we generated a database of candidate genes to be tested in mapped peripheral neuropathies. Unexpectedly, we identified a large cluster of genes that are (1) maximally expressed only in the mature nerve, after myelination is complete, and (2) tied to the metabolism of storage (energy) lipids. Many of these late-onset genes are expressed by adipocytes, which we find constitute the bulk of the epineurial compartment of the adult nerve. However, several such genes, including SREBP-1, SREBP-2, and Lpin1, are also expressed in the endoneurium. We find that Lpin1 null mutations lead to lipoatrophy of the epineurium, and to the dysregulation of a battery of genes required for the regulation of storage lipid metabolism in both the endoneurium and peri/epineurium. Together with the observation that these mutations also result in peripheral neuropathy, our findings demonstrate a crucial role for local storage lipid metabolism in mature peripheral nerve function, and have important implications for the understanding and treatment of peripheral neuropathies that are commonly associated with metabolic diseases such as lipodystrophy and diabetes.
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Affiliation(s)
- Mark H G Verheijen
- Molecular Neurobiology Laboratory, The Salk Institute, La Jolla, California 92037, USA
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