101
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Ercan E, Han JM, Di Nardo A, Winden K, Han MJ, Hoyo L, Saffari A, Leask A, Geschwind DH, Sahin M. Neuronal CTGF/CCN2 negatively regulates myelination in a mouse model of tuberous sclerosis complex. J Exp Med 2017; 214:681-697. [PMID: 28183733 PMCID: PMC5339668 DOI: 10.1084/jem.20160446] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 11/09/2016] [Accepted: 12/30/2016] [Indexed: 12/11/2022] Open
Abstract
Disruption of myelination during development has been implicated in a range of neurodevelopmental disorders including tuberous sclerosis complex (TSC). TSC patients with autism display impairments in white matter integrity. Similarly, mice lacking neuronal Tsc1 have a hypomyelination phenotype. However, the mechanisms that underlie these phenotypes remain unknown. In this study, we demonstrate that neuronal TSC1/2 orchestrates a program of oligodendrocyte maturation through the regulated secretion of connective tissue growth factor (CTGF). We characterize oligodendrocyte maturation both in vitro and in vivo. We find that neuron-specific Tsc1 deletion results in an increase in CTGF secretion that non-cell autonomously stunts oligodendrocyte development and decreases the total number of oligodendrocytes. Genetic deletion of CTGF from neurons, in turn, mitigates the TSC-dependent hypomyelination phenotype. These results show that the mechanistic target of rapamycin (mTOR) pathway in neurons regulates CTGF production and secretion, revealing a paracrine mechanism by which neuronal signaling regulates oligodendrocyte maturation and myelination in TSC. This study highlights the role of mTOR-dependent signaling between neuronal and nonneuronal cells in the regulation of myelin and identifies an additional therapeutic avenue for this disease.
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Affiliation(s)
- Ebru Ercan
- Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115
| | - Juliette M Han
- Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115
| | - Alessia Di Nardo
- Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115
| | - Kellen Winden
- Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115
| | - Min-Joon Han
- Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115.,Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115
| | - Leonie Hoyo
- Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115.,Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115
| | - Afshin Saffari
- Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115
| | - Andrew Leask
- Department of Dentistry, Schulich School of Medicine and Dentistry, London, Ontario N6A 5C1, Canada.,Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, London, Ontario N6A 5C1, Canada
| | - Daniel H Geschwind
- Department of Neurology, University of California, Los Angeles School of Medicine, Los Angeles, CA 90095.,Semel Institute, University of California, Los Angeles School of Medicine, Los Angeles, CA 90095.,Department of Human Genetics, University of California, Los Angeles School of Medicine, Los Angeles, CA 90095
| | - Mustafa Sahin
- Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115 .,Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115
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102
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Guo JN, Tian LY, Liu WY, Mu J, Zhou D. Activation of the Akt/mTOR signaling pathway: A potential response to long-term neuronal loss in the hippocampus after sepsis. Neural Regen Res 2017; 12:1832-1842. [PMID: 29239329 PMCID: PMC5745837 DOI: 10.4103/1673-5374.219044] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Survivors of sepsis may suffer chronic cognitive impairment as a long-term sequela. However, the precise mechanisms of cognitive dysfunction after sepsis are not well understood. We employed the cecal ligation-and-puncture-induced septic mouse model. We observed elevated phosphorylation of Akt, mammalian target of rapamycin (mTOR) and p70S6K on days 14 and 60, progressive neuronal loss in the cornu ammonis 1 region, and abnormal neuronal morphology in the hippocampus in the sepsis mouse model. These findings indicate that changes in neuronal morphology and number in the hippocampus after sepsis were associated with strong activation of the Akt/mTOR signaling pathway, and may reflect a "self-rescuing" feedback response to neuronal loss after sepsis.
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Affiliation(s)
- Jia-Nan Guo
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Lin-Yu Tian
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Wen-Yu Liu
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Jie Mu
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Dong Zhou
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
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