101
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Magdalon J, Sánchez-Sánchez SM, Griesi-Oliveira K, Sertié AL. Dysfunctional mTORC1 Signaling: A Convergent Mechanism between Syndromic and Nonsyndromic Forms of Autism Spectrum Disorder? Int J Mol Sci 2017; 18:ijms18030659. [PMID: 28335463 PMCID: PMC5372671 DOI: 10.3390/ijms18030659] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 03/13/2017] [Accepted: 03/14/2017] [Indexed: 12/28/2022] Open
Abstract
Whereas autism spectrum disorder (ASD) exhibits striking heterogeneity in genetics and clinical presentation, dysfunction of mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway has been identified as a molecular feature common to several well-characterized syndromes with high prevalence of ASD. Additionally, recent findings have also implicated mTORC1 signaling abnormalities in a subset of nonsyndromic ASD, suggesting that defective mTORC1 pathway may be a potential converging mechanism in ASD pathology across different etiologies. However, the mechanistic evidence for a causal link between aberrant mTORC1 pathway activity and ASD neurobehavioral features varies depending on the ASD form involved. In this review, we first discuss six monogenic ASD-related syndromes, including both classical and potentially novel mTORopathies, highlighting their contribution to our understanding of the neurobiological mechanisms underlying ASD, and then we discuss existing evidence suggesting that aberrant mTORC1 signaling may also play a role in nonsyndromic ASD.
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Affiliation(s)
- Juliana Magdalon
- Hospital Israelita Albert Einstein, Centro de Pesquisa Experimental, São Paulo 05652-900, Brazil.
| | - Sandra M Sánchez-Sánchez
- Hospital Israelita Albert Einstein, Centro de Pesquisa Experimental, São Paulo 05652-900, Brazil.
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo 05508-090, Brazil.
| | - Karina Griesi-Oliveira
- Hospital Israelita Albert Einstein, Centro de Pesquisa Experimental, São Paulo 05652-900, Brazil.
| | - Andréa L Sertié
- Hospital Israelita Albert Einstein, Centro de Pesquisa Experimental, São Paulo 05652-900, Brazil.
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102
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Liu X, Li Z, Fan C, Zhang D, Chen J. Genetics implicate common mechanisms in autism and schizophrenia: synaptic activity and immunity. J Med Genet 2017; 54:511-520. [PMID: 28314733 DOI: 10.1136/jmedgenet-2016-104487] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 01/25/2017] [Accepted: 01/26/2017] [Indexed: 11/04/2022]
Abstract
The diagnosis of debilitating psychiatric disorders like autism spectrum disorder (ASD) and schizophrenia (SCHZ) is on the rise. These are severe conditions that lead to social isolation and require lifelong professional care. Improved diagnosis of ASD and SCHZ provides early access to medication and therapy, but the reality is that the mechanisms and the cellular pathology underlying these conditions are mostly unknown at this time. Although both ASD and SCHZ have strong inherited components, genetic risk seems to be distributed in hundreds of variants, each conferring low risk. The poor understanding of the genetics of ASD and SCHZ is a significant hurdle to developing effective treatments for these costly conditions. The recent implementation of next-generation sequencing technologies and the creation of large consortia have started to reveal the genetic bases of ASD and SCHZ. Alterations in gene expression regulation, synaptic architecture and activity and immunity seem to be the main cellular mechanisms contributing to both ASD and SCHZ, a surprising overlap given the distinct phenotypes and onset of these conditions. These diverse pathways seem to converge in aberrant synaptic plasticity and remodelling, which leads to altered connectivity between relevant brain regions. Continuous efforts to understand the genetic basis of ASD and SCHZ will soon lead to significant progress in the mechanistic understanding of these prominent psychiatric disorders and enable the development of disease-modifying therapies for these devastating conditions.
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Affiliation(s)
- Xiaoming Liu
- Department of Neurology, Xuzhou Children's Hospital, Xuzhou, Jiangsu, China
| | - Zhengwei Li
- Department of Pediatric surgery, Xuzhou Children's Hospital, Xuzhou, Jiangsu, China
| | - Conghai Fan
- Department of Neurology, Xuzhou Children's Hospital, Xuzhou, Jiangsu, China
| | - Dongli Zhang
- Department of Neurology, Xuzhou Children's Hospital, Xuzhou, Jiangsu, China
| | - Jiao Chen
- Department of Neurology, Xuzhou Children's Hospital, Xuzhou, Jiangsu, China
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103
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Franco R, Martínez-Pinilla E, Navarro G, Zamarbide M. Potential of GPCRs to modulate MAPK and mTOR pathways in Alzheimer's disease. Prog Neurobiol 2017; 149-150:21-38. [PMID: 28189739 DOI: 10.1016/j.pneurobio.2017.01.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 01/20/2017] [Accepted: 01/22/2017] [Indexed: 02/08/2023]
Abstract
Despite efforts to understand the mechanism of neuronal cell death, finding effective therapies for neurodegenerative diseases is still a challenge. Cognitive deficits are often associated with neurodegenerative diseases. Remarkably, in the absence of consensus biomarkers, diagnosis of diseases such as Alzheimer's still relies on cognitive tests. Unfortunately, all efforts to translate findings in animal models to the patients have been unsuccessful. Alzheimer's disease may be addressed from two different points of view, neuroprotection or cognitive enhancement. Based on recent data, the mammalian target of rapamycin (mTOR) pathway arises as a versatile player whose modulation may impact on mechanisms of both neuroprotection and cognition. Whereas direct targeting of mTOR does not seem to constitute a convenient approach in drug discovery, its indirect modulation by other signaling pathways seems promising. In fact, G-protein-coupled receptors (GPCRs) remain the most common 'druggable' targets and as such pharmacological manipulation of GPCRs with selective ligands may modulate phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K), mitogen-activated protein (MAP) kinase and mTOR signaling pathways. Thus, GPCRs become important targets for potential drug treatments in different neurodegenerative disorders including, but not limited to, Alzheimer's disease. GPCR-mediated modulation of mTOR may take advantage of different GPCRs coupled to different G-dependent and G-independent signal transduction routes, of functional selectivity and/or of biased agonism. Signals mediated by GPCRs may act as coincidence detectors to achieve different benefits in different stages of the neurodegenerative disease.
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Affiliation(s)
- Rafael Franco
- Department of Biochemistry and Molecular Biomedicine and IBUB (Institute of Biomedicine of the University of Barcelona), University of Barcelona, Barcelona, Spain; Centro de investigación en Red: Enfermedades Neurodegenerativas, CIBERNED, Madrid, Spain
| | - Eva Martínez-Pinilla
- Instituto de Neurociencias del Principado de Asturias (INEUROPA), Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, Asturias, Spain
| | - Gemma Navarro
- Department of Biochemistry and Molecular Biomedicine and IBUB (Institute of Biomedicine of the University of Barcelona), University of Barcelona, Barcelona, Spain; Centro de investigación en Red: Enfermedades Neurodegenerativas, CIBERNED, Madrid, Spain
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104
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Metabolism and neurogenesis. Curr Opin Neurobiol 2017; 42:45-52. [DOI: 10.1016/j.conb.2016.11.006] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 11/11/2016] [Accepted: 11/14/2016] [Indexed: 11/22/2022]
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105
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Switon K, Kotulska K, Janusz-Kaminska A, Zmorzynska J, Jaworski J. Molecular neurobiology of mTOR. Neuroscience 2017; 341:112-153. [PMID: 27889578 DOI: 10.1016/j.neuroscience.2016.11.017] [Citation(s) in RCA: 271] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 11/09/2016] [Accepted: 11/13/2016] [Indexed: 01/17/2023]
Abstract
Mammalian/mechanistic target of rapamycin (mTOR) is a serine-threonine kinase that controls several important aspects of mammalian cell function. mTOR activity is modulated by various intra- and extracellular factors; in turn, mTOR changes rates of translation, transcription, protein degradation, cell signaling, metabolism, and cytoskeleton dynamics. mTOR has been repeatedly shown to participate in neuronal development and the proper functioning of mature neurons. Changes in mTOR activity are often observed in nervous system diseases, including genetic diseases (e.g., tuberous sclerosis complex, Pten-related syndromes, neurofibromatosis, and Fragile X syndrome), epilepsy, brain tumors, and neurodegenerative disorders (Alzheimer's disease, Parkinson's disease, and Huntington's disease). Neuroscientists only recently began deciphering the molecular processes that are downstream of mTOR that participate in proper function of the nervous system. As a result, we are gaining knowledge about the ways in which aberrant changes in mTOR activity lead to various nervous system diseases. In this review, we provide a comprehensive view of mTOR in the nervous system, with a special focus on the neuronal functions of mTOR (e.g., control of translation, transcription, and autophagy) that likely underlie the contribution of mTOR to nervous system diseases.
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Affiliation(s)
- Katarzyna Switon
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena Street, Warsaw 02-109, Poland
| | - Katarzyna Kotulska
- Department of Neurology and Epileptology, Children's Memorial Health Institute, Aleja Dzieci Polskich 20, Warsaw 04-730, Poland
| | | | - Justyna Zmorzynska
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena Street, Warsaw 02-109, Poland
| | - Jacek Jaworski
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena Street, Warsaw 02-109, Poland.
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106
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Mohapatra B, Zutshi N, An W, Goetz B, Arya P, Bielecki TA, Mushtaq I, Storck MD, Meza JL, Band V, Band H. An essential role of CBL and CBL-B ubiquitin ligases in mammary stem cell maintenance. Development 2017; 144:1072-1086. [PMID: 28100467 DOI: 10.1242/dev.138164] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 12/29/2016] [Indexed: 12/15/2022]
Abstract
The ubiquitin ligases CBL and CBL-B are negative regulators of tyrosine kinase signaling with established roles in the immune system. However, their physiological roles in epithelial tissues are unknown. Here, we used MMTV-Cre-mediated Cbl gene deletion on a Cbl-b null background, as well as a tamoxifen-inducible mammary stem cell (MaSC)-specific Cbl and Cbl-b double knockout (Cbl/Cbl-b DKO) using Lgr5-EGFP-IRES-CreERT2, to demonstrate a mammary epithelial cell-autonomous requirement of CBL and CBL-B in the maintenance of MaSCs. Using a newly engineered tamoxifen-inducible Cbl and Cbl-b deletion model with a dual fluorescent reporter (Cblflox/flox; Cbl-bflox/flox; Rosa26-CreERT; mT/mG), we show that Cbl/Cbl-b DKO in mammary organoids leads to hyperactivation of AKT-mTOR signaling with depletion of MaSCs. Chemical inhibition of AKT or mTOR rescued MaSCs from Cbl/Cbl-b DKO-induced depletion. Our studies reveal a novel, cell-autonomous requirement of CBL and CBL-B in epithelial stem cell maintenance during organ development and remodeling through modulation of mTOR signaling.
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Affiliation(s)
- Bhopal Mohapatra
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Neha Zutshi
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Department of Pathology & Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Wei An
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Benjamin Goetz
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Priyanka Arya
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Timothy A Bielecki
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Insha Mushtaq
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Department of Pathology & Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Matthew D Storck
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Jane L Meza
- Department of Biostatistics, College of Public Health, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Vimla Band
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Fred & Pamela Buffet Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Hamid Band
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA .,Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Department of Pathology & Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Fred & Pamela Buffet Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
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107
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Pten is necessary for the quiescence and maintenance of adult muscle stem cells. Nat Commun 2017; 8:14328. [PMID: 28094257 PMCID: PMC5247606 DOI: 10.1038/ncomms14328] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 12/16/2016] [Indexed: 02/06/2023] Open
Abstract
Satellite cells (SCs) are myogenic stem cells required for regeneration of adult skeletal muscles. A proper balance among quiescence, activation and differentiation is essential for long-term maintenance of SCs and their regenerative function. Here we show a function of Pten (phosphatase and tensin homologue) in quiescent SCs. Deletion of Pten in quiescent SCs leads to their spontaneous activation and premature differentiation without proliferation, resulting in depletion of SC pool and regenerative failure. However, prior to depletion, Pten-null activated SCs can transiently proliferate upon injury and regenerate injured muscles, but continually decline during regeneration, suggesting an inability to return to quiescence. Mechanistically, Pten deletion increases Akt phosphorylation, which induces cytoplasmic translocation of FoxO1 and suppression of Notch signalling. Accordingly, constitutive activation of Notch1 prevents SC depletion despite Pten deletion. Our findings delineate a critical function of Pten in maintaining SC quiescence and reveal an interaction between Pten and Notch signalling. Pten is known to regulate haematopoietic stem cell functions. Here the authors show that Pten alteration of Notch signalling has stage-specific muscle regenerative functions in muscle stem cells by preventing premature differentiation of quiescent cells and enhancing the self-renewal of activated cells.
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108
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Foerster P, Daclin M, Asm S, Faucourt M, Boletta A, Genovesio A, Spassky N. mTORC1 signaling and primary cilia are required for brain ventricle morphogenesis. Development 2016; 144:201-210. [PMID: 27993979 PMCID: PMC5394754 DOI: 10.1242/dev.138271] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 12/05/2016] [Indexed: 01/06/2023]
Abstract
Radial glial cells (RCGs) are self-renewing progenitor cells that give rise to neurons and glia during embryonic development. Throughout neurogenesis, these cells contact the cerebral ventricles and bear a primary cilium. Although the role of the primary cilium in embryonic patterning has been studied, its role in brain ventricular morphogenesis is poorly characterized. Using conditional mutants, we show that the primary cilia of radial glia determine the size of the surface of their ventricular apical domain through regulation of the mTORC1 pathway. In cilium-less mutants, the orientation of the mitotic spindle in radial glia is also significantly perturbed and associated with an increased number of basal progenitors. The enlarged apical domain of RGCs leads to dilatation of the brain ventricles during late embryonic stages (ventriculomegaly), which initiates hydrocephalus during postnatal stages. These phenotypes can all be significantly rescued by treatment with the mTORC1 inhibitor rapamycin. These results suggest that primary cilia regulate ventricle morphogenesis by acting as a brake on the mTORC1 pathway. This opens new avenues for the diagnosis and treatment of hydrocephalus.
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Affiliation(s)
- Philippe Foerster
- Ecole Normale Supérieure, Institut de Biologie de l'ENS (IBENS), INSERM U1024, and CNRS UMR 8197, PSL Research University, 46 rue d'Ulm, Paris 75005, France
| | - Marie Daclin
- Ecole Normale Supérieure, Institut de Biologie de l'ENS (IBENS), INSERM U1024, and CNRS UMR 8197, PSL Research University, 46 rue d'Ulm, Paris 75005, France
| | - Shihavuddin Asm
- Ecole Normale Supérieure, Institut de Biologie de l'ENS (IBENS), INSERM U1024, and CNRS UMR 8197, PSL Research University, 46 rue d'Ulm, Paris 75005, France
| | - Marion Faucourt
- Ecole Normale Supérieure, Institut de Biologie de l'ENS (IBENS), INSERM U1024, and CNRS UMR 8197, PSL Research University, 46 rue d'Ulm, Paris 75005, France
| | - Alessandra Boletta
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan 20132, Italy
| | - Auguste Genovesio
- Ecole Normale Supérieure, Institut de Biologie de l'ENS (IBENS), INSERM U1024, and CNRS UMR 8197, PSL Research University, 46 rue d'Ulm, Paris 75005, France
| | - Nathalie Spassky
- Ecole Normale Supérieure, Institut de Biologie de l'ENS (IBENS), INSERM U1024, and CNRS UMR 8197, PSL Research University, 46 rue d'Ulm, Paris 75005, France
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109
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Zhang Y, Xu S, Liang KY, Li K, Zou ZP, Yang CL, Tan K, Cao X, Jiang Y, Gao TM, Bai XC. Neuronal mTORC1 Is Required for Maintaining the Nonreactive State of Astrocytes. J Biol Chem 2016; 292:100-111. [PMID: 27895121 DOI: 10.1074/jbc.m116.744482] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 11/10/2016] [Indexed: 11/06/2022] Open
Abstract
Astrocytes respond to CNS insults through reactive astrogliosis, but the underlying mechanisms are unclear. In this study, we show that inactivation of mechanistic target of rapamycin complex (mTORC1) signaling in postnatal neurons induces reactive astrogliosis in mice. Ablation of Raptor (an mTORC1-specific component) in postmitotic neurons abolished mTORC1 activity and produced neurons with smaller soma and fewer dendrites, resulting in microcephaly and aberrant behavior in adult mice. Interestingly, extensive astrogliosis without significant astrocyte proliferation and glial scar formation was observed in these mice. The inhibition of neuronal mTORC1 may activate astrogliosis by reducing neuron-derived fibroblast growth factor 2 (FGF-2), which might trigger FGF receptor signaling in astrocytes to maintain their nonreactive state, and FGF-2 injection successfully prevented astrogliosis in Raptor knock-out mice. This study demonstrates that neuronal mTORC1 inhibits reactive astrogliosis and plays an important role in CNS pathologies.
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Affiliation(s)
- Yue Zhang
- From the Academy of Orthopedics, Guangdong Province, the Third Affiliated Hospital, Southern Medical University, Guangzhou 510515, China.,the Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou 510515, China
| | - Song Xu
- From the Academy of Orthopedics, Guangdong Province, the Third Affiliated Hospital, Southern Medical University, Guangzhou 510515, China.,the Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou 510515, China
| | - Kang-Yan Liang
- the Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou 510515, China
| | - Kai Li
- the Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou 510515, China
| | - Zhi-Peng Zou
- the Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou 510515, China
| | - Cui-Lan Yang
- the Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou 510515, China
| | - Kang Tan
- the Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou 510515, China
| | - Xiong Cao
- the Department of Neurobiology, School of Basic Medical Science, Southern Medical University, Guangzhou 510515, China, and
| | - Yu Jiang
- the Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Tian-Ming Gao
- the Department of Neurobiology, School of Basic Medical Science, Southern Medical University, Guangzhou 510515, China, and
| | - Xiao-Chun Bai
- From the Academy of Orthopedics, Guangdong Province, the Third Affiliated Hospital, Southern Medical University, Guangzhou 510515, China, .,the Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou 510515, China
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110
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Gharibi B, Ghuman M, Hughes FJ. DDIT4 regulates mesenchymal stem cell fate by mediating between HIF1α and mTOR signalling. Sci Rep 2016; 6:36889. [PMID: 27876894 PMCID: PMC5120275 DOI: 10.1038/srep36889] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 10/24/2016] [Indexed: 12/05/2022] Open
Abstract
Stem cell fate decisions to remain quiescent, self-renew or differentiate are largely governed by the interplay between extracellular signals from the niche and the cell intrinsic signal cascades and transcriptional programs. Here we demonstrate that DNA Damage Inducible Transcript 4 (DDIT4) acts as a link between HIF1α and mTOR signalling and regulation of adult stem cell fate. Global gene expression analysis of mesenchymal stem cells (MSC) derived from single clones and live RNA cell sorting showed a direct correlation between DDIT4 and differentiation potentials of MSC. Loss and gain of function analysis demonstrated that DDIT4 activity is directly linked to regulation of mTOR signalling, expression of pluripotency genes and differentiation. Further we demonstrated that DDIT4 exert these effects down-stream to HIF1α. Our findings provide an insight in regulation of adult stem cells homeostasis by two major pathways with opposing functions to coordinate between states of self-renewal and differentiation.
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Affiliation(s)
- Borzo Gharibi
- Division of Tissue Engineering and Biophotonics, Dental Institute, King's College London, Tower Wing, Guy's Hospital, London, SE1 9RT. UK
| | - Mandeep Ghuman
- Division of Tissue Engineering and Biophotonics, Dental Institute, King's College London, Tower Wing, Guy's Hospital, London, SE1 9RT. UK
| | - Francis J Hughes
- Division of Tissue Engineering and Biophotonics, Dental Institute, King's College London, Tower Wing, Guy's Hospital, London, SE1 9RT. UK
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111
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Rubio A, Luoni M, Giannelli SG, Radice I, Iannielli A, Cancellieri C, Di Berardino C, Regalia G, Lazzari G, Menegon A, Taverna S, Broccoli V. Rapid and efficient CRISPR/Cas9 gene inactivation in human neurons during human pluripotent stem cell differentiation and direct reprogramming. Sci Rep 2016; 6:37540. [PMID: 27857203 PMCID: PMC5114606 DOI: 10.1038/srep37540] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 10/31/2016] [Indexed: 12/15/2022] Open
Abstract
The CRISPR/Cas9 system is a rapid and customizable tool for gene editing in mammalian cells. In particular, this approach has widely opened new opportunities for genetic studies in neurological disease. Human neurons can be differentiated in vitro from hPSC (human Pluripotent Stem Cells), hNPCs (human Neural Precursor Cells) or even directly reprogrammed from fibroblasts. Here, we described a new platform which enables, rapid and efficient CRISPR/Cas9-mediated genome targeting simultaneously with three different paradigms for in vitro generation of neurons. This system was employed to inactivate two genes associated with neurological disorder (TSC2 and KCNQ2) and achieved up to 85% efficiency of gene targeting in the differentiated cells. In particular, we devised a protocol that, combining the expression of the CRISPR components with neurogenic factors, generated functional human neurons highly enriched for the desired genome modification in only 5 weeks. This new approach is easy, fast and that does not require the generation of stable isogenic clones, practice that is time consuming and for some genes not feasible.
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Affiliation(s)
- Alicia Rubio
- Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Mirko Luoni
- Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Serena G. Giannelli
- Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Isabella Radice
- Advanced Light and Electron Microscopy Bio-Imaging Centre, Experimental Imaging Centre, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Angelo Iannielli
- Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Cinzia Cancellieri
- Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | | | - Giulia Regalia
- Advanced Light and Electron Microscopy Bio-Imaging Centre, Experimental Imaging Centre, San Raffaele Scientific Institute, 20132 Milan, Italy
- Neuroengineering and medical robotics laboratory, Department of Electronics, Information and Bioengineering, Politecnico di Milano, 20133 Milan, Italy
| | - Giovanna Lazzari
- Avantea srl, Laboratory of Reproductive Technologies, Via Porcellasco 7f, 26100 Cremona, Fondazione Avantea, Cremona
| | - Andrea Menegon
- Advanced Light and Electron Microscopy Bio-Imaging Centre, Experimental Imaging Centre, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Stefano Taverna
- Neuroimmunology Unit, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Vania Broccoli
- Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
- National Research Council (CNR), Institute of Neuroscience, Milan, Italy
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112
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Cavallucci V, Fidaleo M, Pani G. Neural Stem Cells and Nutrients: Poised Between Quiescence and Exhaustion. Trends Endocrinol Metab 2016; 27:756-769. [PMID: 27387597 DOI: 10.1016/j.tem.2016.06.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 06/10/2016] [Accepted: 06/13/2016] [Indexed: 02/08/2023]
Abstract
Adult neurogenesis initiated by neural stem cells (NSCs) contributes to brain homeostasis, damage repair, and cognition. Energy metabolism plays a pivotal role in neurogenic cell fate decisions regarding self-renewal, expansion and multilineage differentiation. NSCs need to fine-tune quiescence and proliferation/commitment to guarantee lifelong neurogenesis and avoid premature exhaustion. Accumulating evidence supports a model whereby calorie restriction or increased energy expenditure reinforce NSC quiescence and promote self-renewal. Conversely, growth/proliferation inputs and anabolic signals, although necessary for neurogenesis, deplete the NSCs pool in the long run. This framework incorporates the emerging neurogenic roles of nutrient-sensing signaling pathways, providing a rationale for the alarming connection between nutritional imbalances, metabolic disorders and accelerated brain aging.
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Affiliation(s)
- Virve Cavallucci
- Institute of General Pathology, Università Cattolica School of Medicine, 00168 Rome, Italy
| | - Marco Fidaleo
- Institute of General Pathology, Università Cattolica School of Medicine, 00168 Rome, Italy
| | - Giovambattista Pani
- Institute of General Pathology, Università Cattolica School of Medicine, 00168 Rome, Italy.
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Traumatic Brain Injury Stimulates Neural Stem Cell Proliferation via Mammalian Target of Rapamycin Signaling Pathway Activation. eNeuro 2016; 3:eN-NWR-0162-16. [PMID: 27822507 PMCID: PMC5089538 DOI: 10.1523/eneuro.0162-16.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 09/07/2016] [Accepted: 09/23/2016] [Indexed: 12/31/2022] Open
Abstract
Neural stem cells in the adult brain possess the ability to remain quiescent until needed in tissue homeostasis or repair. It was previously shown that traumatic brain injury (TBI) stimulated neural stem cell (NSC) proliferation in the adult hippocampus, indicating an innate repair mechanism, but it is unknown how TBI promotes NSC proliferation. In the present study, we observed dramatic activation of mammalian target of rapamycin complex 1 (mTORC1) in the hippocampus of mice with TBI from controlled cortical impact (CCI). The peak of mTORC1 activation in the hippocampal subgranular zone, where NSCs reside, is 24-48 h after trauma, correlating with the peak of TBI-enhanced NSC proliferation. By use of a Nestin-GFP transgenic mouse, in which GFP is ectopically expressed in the NSCs, we found that TBI activated mTORC1 in NSCs. With 5-bromo-2'-deoxyuridine labeling, we observed that TBI increased mTORC1 activation in proliferating NSCs. Furthermore, administration of rapamycin abolished TBI-promoted NSC proliferation. Taken together, these data indicate that mTORC1 activation is required for NSC proliferation postinjury, and thus might serve as a therapeutic target for interventions to augment neurogenesis for brain repair after TBI.
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114
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Switon K, Kotulska K, Janusz-Kaminska A, Zmorzynska J, Jaworski J. Tuberous sclerosis complex: From molecular biology to novel therapeutic approaches. IUBMB Life 2016; 68:955-962. [PMID: 27797139 DOI: 10.1002/iub.1579] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 10/09/2016] [Indexed: 12/20/2022]
Abstract
Tuberous sclerosis complex (TSC) is a rare multi-system disorder, primary manifestations of which are benign tumors and lesions in various organs of the body, including the brain. TSC patients often suffer from epilepsy, mental retardation, and autism spectrum disorder (ASD). Therefore, TSC serves as a model of epilepsy, ASD, and tumorigenesis. TSC is caused by the lack of functional Tsc1-Tsc2 complex, which serves as a major cellular inhibitor of mammalian Target of Rapamycin Complex 1 (mTORC1). mTORC1 is a kinase controlling most of anabolic processes in eukaryotic cells. Consequently, mTORC1 inhibitors, such as rapamycin, serve as experimental or already approved drugs for several TSC symptoms. However, rapalogs, although quite effective, need to be administered chronically and likely for a lifetime, since therapy discontinuation results in tumor regrowth and epilepsy recurrence. Recent studies revealed that metabolism and excitability (in the case of neurons) of cells lacking Tsc1-Tsc2 complex are changed, and these features may potentially be used to treat some of TSC symptoms. In this review, we first provide basic facts about TSC and its molecular background, to next discuss the newest findings in TSC cell biology that can be used to improve existing therapies of TSC and other diseases linked to mTORC1 hyperactivation. © 2016 IUBMB Life, 68(12):955-962, 2016.
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Affiliation(s)
- Katarzyna Switon
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Katarzyna Kotulska
- Department of Neurology and Epileptology, Children's Memorial Health Institute, Warsaw, Poland
| | - Aleksandra Janusz-Kaminska
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Justyna Zmorzynska
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Jacek Jaworski
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Warsaw, Poland
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Grabole N, Zhang JD, Aigner S, Ruderisch N, Costa V, Weber FC, Theron M, Berntenis N, Spleiss O, Ebeling M, Yeo GW, Jagasia R, Kiialainen A. Genomic analysis of the molecular neuropathology of tuberous sclerosis using a human stem cell model. Genome Med 2016; 8:94. [PMID: 27655340 PMCID: PMC5031259 DOI: 10.1186/s13073-016-0347-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 08/18/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Tuberous sclerosis complex (TSC) is a genetic disease characterized by benign tumor growths in multiple organs and neurological symptoms induced by mTOR hyperfunction. Because the molecular pathology is highly complex and the etiology poorly understood, we employed a defined human neuronal model with a single mTOR activating mutation to dissect the disease-relevant molecular responses driving the neuropathology and suggest new targets for treatment. METHODS We investigate the disease phenotype of TSC by neural differentiation of a human stem cell model that had been deleted for TSC2 by genome editing. Comprehensive genomic analysis was performed by RNA sequencing and ribosome profiling to obtain a detailed genome-wide description of alterations on both the transcriptional and translational level. The molecular effect of mTOR inhibitors used in the clinic was monitored and comparison to published data from patient biopsies and mouse models highlights key pathogenic processes. RESULTS TSC2-deficient neural stem cells showed severely reduced neuronal maturation and characteristics of astrogliosis instead. Transcriptome analysis indicated an active inflammatory response and increased metabolic activity, whereas at the level of translation ribosomal transcripts showed a 5'UTR motif-mediated increase in ribosome occupancy. Further, we observed enhanced protein synthesis rates of angiogenic growth factors. Treatment with mTOR inhibitors corrected translational alterations but transcriptional dysfunction persisted. CONCLUSIONS Our results extend the understanding of the molecular pathophysiology of TSC brain lesions, and suggest phenotype-tailored pharmacological treatment strategies.
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Affiliation(s)
- Nils Grabole
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, Basel, 4070, Switzerland.
| | - Jitao David Zhang
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, Basel, 4070, Switzerland
| | - Stefan Aigner
- Department of Cellular and Molecular Medicine, Institute for Genomic Medicine, UCSD Stem Cell Program, Sanford Consortium for Regenerative Medicine, University of California at San Diego, La Jolla, CA, 92037, USA
| | - Nadine Ruderisch
- Roche Pharma Research and Early Development, Neuroscience, Ophthalmology and Rare Diseases, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, Basel, 4070, Switzerland
| | - Veronica Costa
- Roche Pharma Research and Early Development, Neuroscience, Ophthalmology and Rare Diseases, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, Basel, 4070, Switzerland
| | - Felix C Weber
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, Basel, 4070, Switzerland
| | - Michel Theron
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, Basel, 4070, Switzerland
| | - Nikolaos Berntenis
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, Basel, 4070, Switzerland
| | - Olivia Spleiss
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, Basel, 4070, Switzerland
| | - Martin Ebeling
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, Basel, 4070, Switzerland
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, Institute for Genomic Medicine, UCSD Stem Cell Program, Sanford Consortium for Regenerative Medicine, University of California at San Diego, La Jolla, CA, 92037, USA
| | - Ravi Jagasia
- Roche Pharma Research and Early Development, Neuroscience, Ophthalmology and Rare Diseases, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, Basel, 4070, Switzerland
| | - Anna Kiialainen
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, Basel, 4070, Switzerland
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116
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Advancing the understanding of autism disease mechanisms through genetics. Nat Med 2016; 22:345-61. [PMID: 27050589 DOI: 10.1038/nm.4071] [Citation(s) in RCA: 518] [Impact Index Per Article: 64.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 02/26/2016] [Indexed: 12/11/2022]
Abstract
Progress in understanding the genetic etiology of autism spectrum disorders (ASD) has fueled remarkable advances in our understanding of its potential neurobiological mechanisms. Yet, at the same time, these findings highlight extraordinary causal diversity and complexity at many levels ranging from molecules to circuits and emphasize the gaps in our current knowledge. Here we review current understanding of the genetic architecture of ASD and integrate genetic evidence, neuropathology and studies in model systems with how they inform mechanistic models of ASD pathophysiology. Despite the challenges, these advances provide a solid foundation for the development of rational, targeted molecular therapies.
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117
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Chandel NS, Jasper H, Ho TT, Passegué E. Metabolic regulation of stem cell function in tissue homeostasis and organismal ageing. Nat Cell Biol 2016; 18:823-32. [PMID: 27428307 DOI: 10.1038/ncb3385] [Citation(s) in RCA: 208] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 06/08/2016] [Indexed: 12/11/2022]
Abstract
Many tissues and organ systems in metazoans have the intrinsic capacity to regenerate, which is driven and maintained largely by tissue-resident somatic stem cell populations. Ageing is accompanied by a deregulation of stem cell function and a decline in regenerative capacity, often resulting in degenerative diseases. The identification of strategies to maintain stem cell function and regulation is therefore a promising avenue to allay a wide range of age-related diseases. Studies in various organisms have revealed a central role for metabolic pathways in the regulation of stem cell function. Ageing is associated with extensive metabolic changes, and interventions that influence cellular metabolism have long been recognized as robust lifespan-extending measures. In this Review, we discuss recent advances in our understanding of the metabolic control of stem cell function, and how stem cell metabolism relates to homeostasis and ageing.
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Affiliation(s)
- Navdeep S Chandel
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611-2909, USA
| | - Heinrich Jasper
- The Buck Institute for Research on Aging, Novato, California 94945-1400, USA, and the Leibniz Institute on Aging-Fritz Lipmann Institute, Jena 07745, Germany
| | - Theodore T Ho
- Department of Medicine, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San Francisco, California 94143-0667, USA
| | - Emmanuelle Passegué
- Department of Medicine, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San Francisco, California 94143-0667, USA
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118
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Abstract
As a key regulator of cell metabolism and survival, mechanistic target of rapamycin (mTOR) emerges as a novel therapeutic target for Parkinson's disease (PD). A growing body of research indicates that restoring perturbed mTOR signaling in PD models can prevent neuronal cell death. Nevertheless, molecular mechanisms underlying mTOR-mediated effects in PD have not been fully understood yet. Here, we review recent progress in characterizing the association of mTOR signaling with PD risk factors and further discuss the potential roles of mTOR in PD.
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119
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Convulsive seizures from experimental focal cortical dysplasia occur independently of cell misplacement. Nat Commun 2016; 7:11753. [PMID: 27249187 PMCID: PMC4895394 DOI: 10.1038/ncomms11753] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 04/26/2016] [Indexed: 12/19/2022] Open
Abstract
Focal cortical dysplasia (FCD), a local malformation of cortical development, is the most common cause of pharmacoresistant epilepsy associated with life-long neurocognitive impairments. It remains unclear whether neuronal misplacement is required for seizure activity. Here we show that dyslamination and white matter heterotopia are not necessary for seizure generation in a murine model of type II FCDs. These experimental FCDs generated by increasing mTOR activity in layer 2/3 neurons of the medial prefrontal cortex are associated with tonic-clonic seizures and a normal survival rate. Preventing all FCD-related defects, including neuronal misplacement and dysmorphogenesis, with rapamycin treatments from birth eliminates seizures, but seizures recur after rapamycin withdrawal. In addition, bypassing neuronal misplacement and heterotopia using inducible vectors do not prevent seizure occurrence. Collectively, data obtained using our new experimental FCD-associated epilepsy suggest that life-long treatment to reduce neuronal dysmorphogenesis is required to suppress seizures in individuals with FCD.
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120
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Ernst C. Proliferation and Differentiation Deficits are a Major Convergence Point for Neurodevelopmental Disorders. Trends Neurosci 2016; 39:290-299. [DOI: 10.1016/j.tins.2016.03.001] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 03/01/2016] [Accepted: 03/02/2016] [Indexed: 12/13/2022]
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121
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Abstract
Focal cortical dysplasia is a common cause of medication resistant epilepsy. A better understanding of its presentation, pathophysiology and consequences have helped us improved its treatment and outcome. This paper reviews the most recent classification, pathophysiology and imaging findings in clinical research as well as the knowledge gained from studying genetic and lesional animal models of focal cortical dysplasia. This review of this recently gained knowledge will most likely help develop new research models and new therapeutic targets for patients with epilepsy associated with focal cortical dysplasia.
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122
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Costa V, Aigner S, Vukcevic M, Sauter E, Behr K, Ebeling M, Dunkley T, Friedlein A, Zoffmann S, Meyer CA, Knoflach F, Lugert S, Patsch C, Fjeldskaar F, Chicha-Gaudimier L, Kiialainen A, Piraino P, Bedoucha M, Graf M, Jessberger S, Ghosh A, Bischofberger J, Jagasia R. mTORC1 Inhibition Corrects Neurodevelopmental and Synaptic Alterations in a Human Stem Cell Model of Tuberous Sclerosis. Cell Rep 2016; 15:86-95. [PMID: 27052171 DOI: 10.1016/j.celrep.2016.02.090] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 01/23/2016] [Accepted: 02/25/2016] [Indexed: 12/21/2022] Open
Abstract
Hyperfunction of the mTORC1 pathway has been associated with idiopathic and syndromic forms of autism spectrum disorder (ASD), including tuberous sclerosis, caused by loss of either TSC1 or TSC2. It remains largely unknown how developmental processes and biochemical signaling affected by mTORC1 dysregulation contribute to human neuronal dysfunction. Here, we have characterized multiple stages of neurogenesis and synapse formation in human neurons derived from TSC2-deleted pluripotent stem cells. Homozygous TSC2 deletion causes severe developmental abnormalities that recapitulate pathological hallmarks of cortical malformations in patients. Both TSC2(+/-) and TSC2(-/-) neurons display altered synaptic transmission paralleled by molecular changes in pathways associated with autism, suggesting the convergence of pathological mechanisms in ASD. Pharmacological inhibition of mTORC1 corrects developmental abnormalities and synaptic dysfunction during independent developmental stages. Our results uncouple stage-specific roles of mTORC1 in human neuronal development and contribute to a better understanding of the onset of neuronal pathophysiology in tuberous sclerosis.
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Affiliation(s)
- Veronica Costa
- Roche Pharmaceutical Research and Early Development, Neuroscience Ophthalmology and Rare Diseases Discovery & Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland.
| | - Stefan Aigner
- Roche Pharmaceutical Research and Early Development, Neuroscience Ophthalmology and Rare Diseases Discovery & Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Mirko Vukcevic
- Department of Biomedicine, University of Basel, Pestalozzistrasse 20, 4056 Basel, Switzerland
| | - Evelyn Sauter
- Roche Pharmaceutical Research and Early Development, Neuroscience Ophthalmology and Rare Diseases Discovery & Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Katharina Behr
- Department of Biomedicine, University of Basel, Pestalozzistrasse 20, 4056 Basel, Switzerland
| | - Martin Ebeling
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Tom Dunkley
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Arno Friedlein
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Sannah Zoffmann
- Roche Pharmaceutical Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Claas A Meyer
- Roche Pharmaceutical Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Frédéric Knoflach
- Roche Pharmaceutical Research and Early Development, Neuroscience Ophthalmology and Rare Diseases Discovery & Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Sebastian Lugert
- Roche Pharmaceutical Research and Early Development, Neuroscience Ophthalmology and Rare Diseases Discovery & Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Christoph Patsch
- Roche Pharmaceutical Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Fatiha Fjeldskaar
- Roche Pharmaceutical Research and Early Development, Neuroscience Ophthalmology and Rare Diseases Discovery & Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Laurie Chicha-Gaudimier
- Department of Neurosurgery, Universitätsspital Basel, ZLF 20 Hebelstrasse, 4031 Basel, Switzerland
| | - Anna Kiialainen
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Paolo Piraino
- Pvalue Research SRL, 29015 Castel San Giovanni, Italy
| | - Marc Bedoucha
- Roche Pharmaceutical Research and Early Development, Neuroscience Ophthalmology and Rare Diseases Discovery & Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Martin Graf
- Roche Pharmaceutical Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Sebastian Jessberger
- Brain Research Institute, Faculty of Medicine and Science, University of Zurich, 8057 Zurich, Switzerland
| | - Anirvan Ghosh
- Roche Pharmaceutical Research and Early Development, Neuroscience Ophthalmology and Rare Diseases Discovery & Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Josef Bischofberger
- Department of Biomedicine, University of Basel, Pestalozzistrasse 20, 4056 Basel, Switzerland
| | - Ravi Jagasia
- Roche Pharmaceutical Research and Early Development, Neuroscience Ophthalmology and Rare Diseases Discovery & Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland.
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123
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A CREB-Sirt1-Hes1 Circuitry Mediates Neural Stem Cell Response to Glucose Availability. Cell Rep 2016; 14:1195-1205. [PMID: 26804914 DOI: 10.1016/j.celrep.2015.12.092] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 08/21/2015] [Accepted: 12/20/2015] [Indexed: 01/21/2023] Open
Abstract
Adult neurogenesis plays increasingly recognized roles in brain homeostasis and repair and is profoundly affected by energy balance and nutrients. We found that the expression of Hes-1 (hairy and enhancer of split 1) is modulated in neural stem and progenitor cells (NSCs) by extracellular glucose through the coordinated action of CREB (cyclic AMP responsive element binding protein) and Sirt-1 (Sirtuin 1), two cellular nutrient sensors. Excess glucose reduced CREB-activated Hes-1 expression and results in impaired cell proliferation. CREB-deficient NSCs expanded poorly in vitro and did not respond to glucose availability. Elevated glucose also promoted Sirt-1-dependent repression of the Hes-1 promoter. Conversely, in low glucose, CREB replaced Sirt-1 on the chromatin associated with the Hes-1 promoter enhancing Hes-1 expression and cell proliferation. Thus, the glucose-regulated antagonism between CREB and Sirt-1 for Hes-1 transcription participates in the metabolic regulation of neurogenesis.
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124
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Tee AR, Sampson JR, Pal DK, Bateman JM. The role of mTOR signalling in neurogenesis, insights from tuberous sclerosis complex. Semin Cell Dev Biol 2016; 52:12-20. [PMID: 26849906 DOI: 10.1016/j.semcdb.2016.01.040] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 01/05/2016] [Accepted: 01/25/2016] [Indexed: 11/30/2022]
Abstract
Understanding the development and function of the nervous system is one of the foremost aims of current biomedical research. The nervous system is generated during a relatively short period of intense neurogenesis that is orchestrated by a number of key molecular signalling pathways. Even subtle defects in the activity of these molecules can have serious repercussions resulting in neurological, neurodevelopmental and neurocognitive problems including epilepsy, intellectual disability and autism. Tuberous sclerosis complex (TSC) is a monogenic disease characterised by these problems and by the formation of benign tumours in multiple organs, including the brain. TSC is caused by mutations in the TSC1 or TSC2 gene leading to activation of the mechanistic target of rapamycin (mTOR) signalling pathway. A desire to understand the neurological manifestations of TSC has stimulated research into the role of the mTOR pathway in neurogenesis. In this review we describe TSC neurobiology and how the use of animal model systems has provided insights into the roles of mTOR signalling in neuronal differentiation and migration. Recent progress in this field has identified novel mTOR pathway components regulating neuronal differentiation. The roles of mTOR signalling and aberrant neurogenesis in epilepsy are also discussed. Continuing efforts to understand mTOR neurobiology will help to identify new therapeutic targets for TSC and other neurological diseases.
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Affiliation(s)
- Andrew R Tee
- Institute of Cancer & Genetics, Cardiff University School of Medicine, Institute of Medical Genetics Building, Heath Park, Cardiff CF14 4XN UK
| | - Julian R Sampson
- Institute of Cancer & Genetics, Cardiff University School of Medicine, Institute of Medical Genetics Building, Heath Park, Cardiff CF14 4XN UK
| | - Deb K Pal
- Department of Basic & Clinical Neurosciences, Institute of Psychiatry, Psychology & Neuroscience, King's College, London SE5 8RX UK
| | - Joseph M Bateman
- Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London SE1 1UL UK.
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125
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Maiese K. Targeting molecules to medicine with mTOR, autophagy and neurodegenerative disorders. Br J Clin Pharmacol 2015; 82:1245-1266. [PMID: 26469771 DOI: 10.1111/bcp.12804] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Revised: 10/11/2015] [Accepted: 10/13/2015] [Indexed: 12/14/2022] Open
Abstract
Neurodegenerative disorders are significantly increasing in incidence as the age of the global population continues to climb with improved life expectancy. At present, more than 30 million individuals throughout the world are impacted by acute and chronic neurodegenerative disorders with limited treatment strategies. The mechanistic target of rapamycin (mTOR), also known as the mammalian target of rapamycin, is a 289 kDa serine/threonine protein kinase that offers exciting possibilities for novel treatment strategies for a host of neurodegenerative diseases that include Alzheimer's disease, Parkinson's disease, Huntington's disease, epilepsy, stroke and trauma. mTOR governs the programmed cell death pathways of apoptosis and autophagy that can determine neuronal stem cell development, precursor cell differentiation, cell senescence, cell survival and ultimate cell fate. Coupled to the cellular biology of mTOR are a number of considerations for the development of novel treatments involving the fine control of mTOR signalling, tumourigenesis, complexity of the apoptosis and autophagy relationship, functional outcome in the nervous system, and the intimately linked pathways of growth factors, phosphoinositide 3-kinase (PI 3-K), protein kinase B (Akt), AMP activated protein kinase (AMPK), silent mating type information regulation two homologue one (Saccharomyces cerevisiae) (SIRT1) and others. Effective clinical translation of the cellular signalling mechanisms of mTOR offers provocative avenues for new drug development in the nervous system tempered only by the need to elucidate further the intricacies of the mTOR pathway.
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Affiliation(s)
- Kenneth Maiese
- Cellular and Molecular Signaling, Newark, New Jersey, 07101, USA.
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126
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Biever A, Valjent E, Puighermanal E. Ribosomal Protein S6 Phosphorylation in the Nervous System: From Regulation to Function. Front Mol Neurosci 2015; 8:75. [PMID: 26733799 PMCID: PMC4679984 DOI: 10.3389/fnmol.2015.00075] [Citation(s) in RCA: 139] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 11/23/2015] [Indexed: 01/31/2023] Open
Abstract
Since the discovery of the phosphorylation of the 40S ribosomal protein S6 (rpS6) about four decades ago, much effort has been made to uncover the molecular mechanisms underlying the regulation of this post-translational modification. In the field of neuroscience, rpS6 phosphorylation is commonly used as a readout of the mammalian target of rapamycin complex 1 signaling activation or as a marker for neuronal activity. Nevertheless, its biological role in neurons still remains puzzling. Here we review the pharmacological and physiological stimuli regulating this modification in the nervous system as well as the pathways that transduce these signals into rpS6 phosphorylation. Altered rpS6 phosphorylation observed in various genetic and pathophysiological mouse models is also discussed. Finally, we examine the current state of knowledge on the physiological role of this post-translational modification and highlight the questions that remain to be addressed.
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Affiliation(s)
- Anne Biever
- Centre National de la Recherche Scientifique, UMR5203, Institut de Génomique FonctionnelleMontpellier, France; Institut National de la Santé et de la Recherche Médicale, U1191Montpellier, France; Université de Montpellier, UMR-5203Montpellier, France
| | - Emmanuel Valjent
- Centre National de la Recherche Scientifique, UMR5203, Institut de Génomique FonctionnelleMontpellier, France; Institut National de la Santé et de la Recherche Médicale, U1191Montpellier, France; Université de Montpellier, UMR-5203Montpellier, France
| | - Emma Puighermanal
- Centre National de la Recherche Scientifique, UMR5203, Institut de Génomique FonctionnelleMontpellier, France; Institut National de la Santé et de la Recherche Médicale, U1191Montpellier, France; Université de Montpellier, UMR-5203Montpellier, France
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127
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Moffat JJ, Ka M, Jung EM, Kim WY. Genes and brain malformations associated with abnormal neuron positioning. Mol Brain 2015; 8:72. [PMID: 26541977 PMCID: PMC4635534 DOI: 10.1186/s13041-015-0164-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 10/31/2015] [Indexed: 01/05/2023] Open
Abstract
Neuronal positioning is a fundamental process during brain development. Abnormalities in this process cause several types of brain malformations and are linked to neurodevelopmental disorders such as autism, intellectual disability, epilepsy, and schizophrenia. Little is known about the pathogenesis of developmental brain malformations associated with abnormal neuron positioning, which has hindered research into potential treatments. However, recent advances in neurogenetics provide clues to the pathogenesis of aberrant neuronal positioning by identifying causative genes. This may help us form a foundation upon which therapeutic tools can be developed. In this review, we first provide a brief overview of neural development and migration, as they relate to defects in neuronal positioning. We then discuss recent progress in identifying genes and brain malformations associated with aberrant neuronal positioning during human brain development.
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Affiliation(s)
- Jeffrey J Moffat
- Department of Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, 985960 Nebraska Medical Center, Omaha, NE, 68198-5960, USA.
| | - Minhan Ka
- Department of Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, 985960 Nebraska Medical Center, Omaha, NE, 68198-5960, USA.
| | - Eui-Man Jung
- Department of Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, 985960 Nebraska Medical Center, Omaha, NE, 68198-5960, USA.
| | - Woo-Yang Kim
- Department of Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, 985960 Nebraska Medical Center, Omaha, NE, 68198-5960, USA.
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128
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Joppé SE, Hamilton LK, Cochard LM, Levros LC, Aumont A, Barnabé-Heider F, Fernandes KJL. Bone morphogenetic protein dominantly suppresses epidermal growth factor-induced proliferative expansion of adult forebrain neural precursors. Front Neurosci 2015; 9:407. [PMID: 26576147 PMCID: PMC4625077 DOI: 10.3389/fnins.2015.00407] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 10/12/2015] [Indexed: 01/17/2023] Open
Abstract
A single asymmetric division by an adult neural stem cell (NSC) ultimately generates dozens of differentiated progeny, a feat made possible by the proliferative expansion of transit-amplifying progenitor cells (TAPs). Although NSC activation and TAP expansion is determined by pro- and anti-proliferative signals found within the niche, remarkably little is known about how these cells integrate simultaneous conflicting signals. We investigated this question focusing on the subventricular zone (SVZ) niche of the adult murine forebrain. Using primary cultures of SVZ cells, we demonstrate that Epidermal Growth Factor (EGF) and Bone Morphogenetic Protein (BMP)-2 are particularly powerful pro- and anti-proliferative factors for SVZ-derived neural precursors. Dose-response experiments showed that when simultaneously exposed to both signals, BMP dominantly suppressed EGF-induced proliferation; moreover, this dominance extended to all parameters of neural precursor behavior tested, including inhibition of proliferation, modulation of cell cycle, promotion of differentiation, and increase of cell death. BMP's anti-proliferative effect did not involve inhibition of mTORC1 or ERK signaling, key mediators of EGF-induced proliferation, and had distinct stage-specific consequences, promoting TAP differentiation but NSC quiescence. In line with these in vitro data, in vivo experiments showed that exogenous BMP limits EGF-induced proliferation of TAPs while inhibition of BMP-SMAD signaling promotes activation of quiescent NSCs. These findings clarify the stage-specific effects of BMPs on SVZ neural precursors, and support a hierarchical model in which the anti-proliferative effects of BMP dominate over EGF proliferation signaling to constitutively drive TAP differentiation and NSC quiescence.
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Affiliation(s)
- Sandra E Joppé
- Central Nervous System Research Group, Department of Pathology and Cell Biology, and Department of Neurosciences, Research Center of the University of Montreal Hospital, University of Montreal Montreal, QC, Canada
| | - Laura K Hamilton
- Central Nervous System Research Group, Department of Pathology and Cell Biology, and Department of Neurosciences, Research Center of the University of Montreal Hospital, University of Montreal Montreal, QC, Canada
| | - Loic M Cochard
- Central Nervous System Research Group, Department of Pathology and Cell Biology, and Department of Neurosciences, Research Center of the University of Montreal Hospital, University of Montreal Montreal, QC, Canada
| | - Louis-Charles Levros
- Central Nervous System Research Group, Department of Pathology and Cell Biology, and Department of Neurosciences, Research Center of the University of Montreal Hospital, University of Montreal Montreal, QC, Canada
| | - Anne Aumont
- Central Nervous System Research Group, Department of Pathology and Cell Biology, and Department of Neurosciences, Research Center of the University of Montreal Hospital, University of Montreal Montreal, QC, Canada
| | | | - Karl J L Fernandes
- Central Nervous System Research Group, Department of Pathology and Cell Biology, and Department of Neurosciences, Research Center of the University of Montreal Hospital, University of Montreal Montreal, QC, Canada
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129
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Complex Neurological Phenotype in Mutant Mice Lacking Tsc2 in Excitatory Neurons of the Developing Forebrain(123). eNeuro 2015; 2:eN-NWR-0046-15. [PMID: 26693177 PMCID: PMC4676199 DOI: 10.1523/eneuro.0046-15.2015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 09/09/2015] [Accepted: 09/14/2015] [Indexed: 11/25/2022] Open
Abstract
Mutations in the TSC1 and TSC2 genes cause tuberous sclerosis complex (TSC), a genetic disease often associated with epilepsy, intellectual disability, and autism, and characterized by the presence of anatomical malformations in the brain as well as tumors in other organs. The TSC1 and TSC2 proteins form a complex that inhibits mammalian target of rapamycin complex 1 (mTORC1) signaling. Previous animal studies demonstrated that Tsc1 or Tsc2 loss of function in the developing brain affects the intrinsic development of neural progenitor cells, neurons, or glia. However, the interplay between different cellular elements during brain development was not previously investigated. In this study, we generated a novel mutant mouse line (NEX-Tsc2) in which the Tsc2 gene is deleted specifically in postmitotic excitatory neurons of the developing forebrain. Homozygous mutant mice failed to thrive and died prematurely, whereas heterozygous mice appeared normal. Mutant mice exhibited distinct neuroanatomical abnormalities, including malpositioning of selected neuronal populations, neuronal hypertrophy, and cortical astrogliosis. Intrinsic neuronal defects correlated with increased mTORC1 signaling, whereas astrogliosis did not result from altered intrinsic signaling, since these cells were not directly affected by the gene knockout strategy. All neuronal and non-neuronal abnormalities were suppressed by continuous postnatal treatment with the mTORC1 inhibitor RAD001. The data suggest that the loss of Tsc2 and mTORC1 signaling activation in excitatory neurons not only disrupts their intrinsic development, but also disrupts the development of cortical astrocytes, likely through the mTORC1-dependent expression of abnormal signaling proteins. This work thus provides new insights into cell-autonomous and non-cell-autonomous functions of Tsc2 in brain development.
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130
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Jones I, Hägglund AC, Törnqvist G, Nord C, Ahlgren U, Carlsson L. A novel mouse model of tuberous sclerosis complex (TSC): eye-specific Tsc1-ablation disrupts visual-pathway development. Dis Model Mech 2015; 8:1517-29. [PMID: 26449264 PMCID: PMC4728318 DOI: 10.1242/dmm.021972] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 09/30/2015] [Indexed: 12/21/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant syndrome that is best characterised by neurodevelopmental deficits and the presence of benign tumours (called hamartomas) in affected organs. This multi-organ disorder results from inactivating point mutations in either the TSC1 or the TSC2 genes and consequent activation of the canonical mammalian target of rapamycin complex 1 signalling (mTORC1) pathway. Because lesions to the eye are central to TSC diagnosis, we report here the generation and characterisation of the first eye-specific TSC mouse model. We demonstrate that conditional ablation of Tsc1 in eye-committed progenitor cells leads to the accelerated differentiation and subsequent ectopic radial migration of retinal ganglion cells. This results in an increase in retinal ganglion cell apoptosis and consequent regionalised axonal loss within the optic nerve and topographical changes to the contra- and ipsilateral input within the dorsal lateral geniculate nucleus. Eyes from adult mice exhibit aberrant retinal architecture and display all the classic neuropathological hallmarks of TSC, including an increase in organ and cell size, ring heterotopias, hamartomas with retinal detachment, and lamination defects. Our results provide the first major insight into the molecular etiology of TSC within the developing eye and demonstrate a pivotal role for Tsc1 in regulating various aspects of visual-pathway development. Our novel mouse model therefore provides a valuable resource for future studies concerning the molecular mechanisms underlying TSC and also as a platform to evaluate new therapeutic approaches for the treatment of this multi-organ disorder. Editors' choice: Conditional deletion of Tsc1 in the eye results in hamartoma formation and defects in retinal ganglion cell development – a novel mouse model providing insights into visual pathway involvement in TSC.
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Affiliation(s)
- Iwan Jones
- Umeå Center for Molecular Medicine (UCMM), Umeå University, Umeå 901 87, Sweden
| | - Anna-Carin Hägglund
- Umeå Center for Molecular Medicine (UCMM), Umeå University, Umeå 901 87, Sweden
| | - Gunilla Törnqvist
- Umeå Center for Molecular Medicine (UCMM), Umeå University, Umeå 901 87, Sweden
| | - Christoffer Nord
- Umeå Center for Molecular Medicine (UCMM), Umeå University, Umeå 901 87, Sweden
| | - Ulf Ahlgren
- Umeå Center for Molecular Medicine (UCMM), Umeå University, Umeå 901 87, Sweden
| | - Leif Carlsson
- Umeå Center for Molecular Medicine (UCMM), Umeå University, Umeå 901 87, Sweden
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131
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Ali S, Wall IB, Mason C, Pelling AE, Veraitch FS. The effect of Young's modulus on the neuronal differentiation of mouse embryonic stem cells. Acta Biomater 2015; 25:253-267. [PMID: 26159105 DOI: 10.1016/j.actbio.2015.07.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 05/27/2015] [Accepted: 07/05/2015] [Indexed: 12/15/2022]
Abstract
There is substantial evidence that cells produce a diverse response to changes in ECM stiffness depending on their identity. Our aim was to understand how stiffness impacts neuronal differentiation of embryonic stem cells (ESC's), and how this varies at three specific stages of the differentiation process. In this investigation, three effects of stiffness on cells were considered; attachment, expansion and phenotypic changes during differentiation. Stiffness was varied from 2 kPa to 18 kPa to finally 35 kPa. Attachment was found to decrease with increasing stiffness for both ESC's (with a 95% decrease on 35 kPa compared to 2 kPa) and neural precursors (with a 83% decrease on 35 kPa). The attachment of immature neurons was unaffected by stiffness. Expansion was independent of stiffness for all cell types, implying that the proliferation of cells during this differentiation process was independent of Young's modulus. Stiffness had no effect upon phenotypic changes during differentiation for mESC's and neural precursors. 2 kPa increased the proportion of cells that differentiated from immature into mature neurons. Taken together our findings imply that the impact of Young's modulus on attachment diminishes as neuronal cells become more mature. Conversely, the impact of Young's modulus on changes in phenotype increased as cells became more mature.
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132
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Tabata Y, Murai N, Sasaki T, Taniguchi S, Suzuki S, Yamazaki K, Ito M. Multiparametric Phenotypic Screening System for Profiling Bioactive Compounds Using Human Fetal Hippocampal Neural Stem/Progenitor Cells. ACTA ACUST UNITED AC 2015; 20:1074-83. [DOI: 10.1177/1087057115598119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 07/07/2015] [Indexed: 01/25/2023]
Abstract
Stem cell research has been progressing rapidly, contributing to regenerative biology and regenerative medicine. In this field, small-molecule compounds affecting stem cell proliferation/differentiation have been explored to understand stem cell biology and support regenerative medicine. In this study, we established a multiparametric screening system to detect bioactive compounds affecting the cell fate of human neural stem/progenitor cells (NSCs/NPCs), using human fetal hippocampal NSCs/NPCs, HIP-009 cells. We examined effects of 410 compounds, which were collected based on mechanisms of action (MOAs) and chemotypes, on HIP-009’s cell fate (self-renewal, neuronal and astrocytic differentiation) and morphology by automated multiparametric assays and profiled induced cellular phenotypes. We found that this screening classified compounds with the same MOAs into subgroups according to additional pharmacological effects (e.g., mammalian target of rapamycin complex 1 [mTORC1] inhibitors and mTORC1/mTORC2 dual inhibitors among mTOR inhibitors). Moreover, it identified compounds that have off-target effects under matrix analyses of MOAs and structure similarities (e.g., neurotropic effects of amitriptyline among tri- and tetracyclic compounds). Therefore, this automated, medium-throughput and multiparametric screening system is useful for finding compounds that affect the cell fate of human NSCs/NPCs for supporting regenerative medicine and to fingerprint compounds based on human stem cells’ multipotency, leading to understanding of stem cell biology.
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Affiliation(s)
- Yoshikuni Tabata
- Next Generation Systems CFU, Eisai Product Creation Systems, Eisai Co., Ltd., Tokodai, Tsukuba, Ibaraki, Japan
| | - Norio Murai
- Next Generation Systems CFU, Eisai Product Creation Systems, Eisai Co., Ltd., Tokodai, Tsukuba, Ibaraki, Japan
| | - Takeo Sasaki
- Global Discovery Research, Neuroscience and General Medicine PCU, Eisai Product Creation Systems, Eisai Co., Ltd., Tokodai, Tsukuba, Ibaraki, Japan
| | - Sachie Taniguchi
- Next Generation Systems CFU, Eisai Product Creation Systems, Eisai Co., Ltd., Tokodai, Tsukuba, Ibaraki, Japan
| | - Shuichi Suzuki
- Next Generation Systems CFU, Eisai Product Creation Systems, Eisai Co., Ltd., Tokodai, Tsukuba, Ibaraki, Japan
| | - Kazuto Yamazaki
- Next Generation Systems CFU, Eisai Product Creation Systems, Eisai Co., Ltd., Tokodai, Tsukuba, Ibaraki, Japan
| | - Masashi Ito
- Next Generation Systems CFU, Eisai Product Creation Systems, Eisai Co., Ltd., Tokodai, Tsukuba, Ibaraki, Japan
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133
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Yang M, Yang SL, Herrlinger S, Liang C, Dzieciatkowska M, Hansen KC, Desai R, Nagy A, Niswander L, Moss EG, Chen JF. Lin28 promotes the proliferative capacity of neural progenitor cells in brain development. Development 2015; 142:1616-27. [PMID: 25922525 DOI: 10.1242/dev.120543] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Neural progenitor cells (NPCs) have distinct proliferation capacities at different stages of brain development. Lin28 is an RNA-binding protein with two homologs in mice: Lin28a and Lin28b. Here we show that Lin28a/b are enriched in early NPCs and their expression declines during neural differentiation. Lin28a single-knockout mice show reduced NPC proliferation, enhanced cell cycle exit and a smaller brain, whereas mice lacking both Lin28a alleles and one Lin28b allele display similar but more severe phenotypes. Ectopic expression of Lin28a in mice results in increased NPC proliferation, NPC numbers and brain size. Mechanistically, Lin28a physically and functionally interacts with Imp1 (Igf2bp1) and regulates Igf2-mTOR signaling. The function of Lin28a/b in NPCs could be attributed, at least in part, to the regulation of their mRNA targets that encode Igf1r and Hmga2. Thus, Lin28a and Lin28b have overlapping functions in temporally regulating NPC proliferation during early brain development.
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Affiliation(s)
- Mei Yang
- Department of Genetics, Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Si-Lu Yang
- Department of Genetics, Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Stephanie Herrlinger
- Department of Genetics, Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Chen Liang
- Department of Genetics, Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Monika Dzieciatkowska
- Department of Biochemistry & Molecular Genetics, University of Colorado Denver, Aurora, CO 80045, USA
| | - Kirk C Hansen
- Department of Biochemistry & Molecular Genetics, University of Colorado Denver, Aurora, CO 80045, USA
| | - Ridham Desai
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5T 3L9, Canada
| | - Andras Nagy
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5T 3L9, Canada
| | - Lee Niswander
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Children's Hospital Colorado, Aurora, CO 80045, USA
| | - Eric G Moss
- Department of Molecular Biology, Rowan University, Stratford, NJ 08084, USA
| | - Jian-Fu Chen
- Department of Genetics, Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602, USA
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134
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Davis PE, Peters JM, Krueger DA, Sahin M. Tuberous Sclerosis: A New Frontier in Targeted Treatment of Autism. Neurotherapeutics 2015; 12:572-83. [PMID: 25986747 PMCID: PMC4489948 DOI: 10.1007/s13311-015-0359-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Tuberous sclerosis complex (TSC) is a genetic disorder with a high prevalence of autism spectrum disorder (ASD). Tremendous progress in understanding the pathogenesis of TSC has been made in recent years, along with initial trials of medical treatment aimed specifically at the underlying mechanism of the disorder. At the cellular level, loss of TSC1 or TSC2 results in upregulation of the mechanistic target of rapamycin (mTOR) pathway. At the circuitry level, TSC and mTOR play crucial roles in axonal, dendritic, and synaptic development and function. In this review, we discuss the molecular mechanism underlying TSC, and how this disease results in aberrant neural connectivity at multiple levels in the central nervous system, leading to ASD symptoms. We then review recent advances in mechanism-based treatments of TSC, and the promise that these treatments provide for future mechanism-based treatment of ASD. Because of these recent advances, TSC represents an ideal model for how to make progress in understanding and treating the mechanisms that underlie ASD in general.
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Affiliation(s)
- Peter E. Davis
- />Department of Neurology, Boston Children’s Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, 02115 MA USA
| | - Jurriaan M. Peters
- />Department of Neurology, Boston Children’s Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, 02115 MA USA
| | - Darcy A. Krueger
- />Division of Neurology, Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH USA
| | - Mustafa Sahin
- />Department of Neurology, Boston Children’s Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, 02115 MA USA
- />F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA USA
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135
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Kirschstein T, Köhling R. Animal models of tumour-associated epilepsy. J Neurosci Methods 2015; 260:109-17. [PMID: 26092434 DOI: 10.1016/j.jneumeth.2015.06.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 06/05/2015] [Accepted: 06/08/2015] [Indexed: 01/26/2023]
Abstract
Brain tumours cause a sizeable proportion of epilepsies in adulthood, and actually can be etiologically responsible also for childhood epilepsies. Conversely, seizures are often first clinical signs of a brain tumour. Nevertheless, several issues of brain-tumour associated seizures and epilepsies are far from understood, or clarified regarding clinical consensus. These include both the specific mechanisms of epileptogenesis related to different tumour types, the possible relationship between malignancy and seizure emergence, the interaction between tumour mass and surrounding neuronal networks, and - not least - the best treatment options depending on different tumour types. To investigate these issues, experimental models of tumour-induced epilepsies are necessary. This review concentrates on the description of currently used models, focusing on methodological aspects. It highlights advantages and shortcomings of these models, and identifies future experimental challenges.
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Affiliation(s)
- Timo Kirschstein
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Gertrudenstrasse 9, 18057 Rostock, Germany
| | - Rüdiger Köhling
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Gertrudenstrasse 9, 18057 Rostock, Germany.
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136
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Bedogni F, Cobolli Gigli C, Pozzi D, Rossi RL, Scaramuzza L, Rossetti G, Pagani M, Kilstrup-Nielsen C, Matteoli M, Landsberger N. Defects During Mecp2 Null Embryonic Cortex Development Precede the Onset of Overt Neurological Symptoms. Cereb Cortex 2015; 26:2517-2529. [PMID: 25979088 DOI: 10.1093/cercor/bhv078] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
MeCP2 is associated with several neurological disorders; of which, Rett syndrome undoubtedly represents the most frequent. Its molecular roles, however, are still unclear, and data from animal models often describe adult, symptomatic stages, while MeCP2 functions during embryonic development remain elusive. We describe the pattern and timing of Mecp2 expression in the embryonic neocortex highlighting its low but consistent expression in virtually all cells and show the unexpected occurrence of transcriptional defects in the Mecp2 null samples at a stage largely preceding the onset of overt symptoms. Through the deregulated expression of ionic channels and glutamatergic receptors, the lack of Mecp2 during early neuronal maturation leads to the reduction in the neuronal responsiveness to stimuli. We suggest that such features concur to morphological alterations that begin affecting Mecp2 null neurons around the perinatal age and become evident later in adulthood. We indicate MeCP2 as a key modulator of the transcriptional mechanisms regulating cerebral cortex development. Neurological phenotypes of MECP2 patients could thus be the cumulative result of different adverse events that are already present at stages when no obvious signs of the pathology are evident and are worsened by later impairments affecting the central nervous system during maturation and maintenance of its functionality.
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Affiliation(s)
- Francesco Bedogni
- San Raffaele Rett Research Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Clementina Cobolli Gigli
- San Raffaele Rett Research Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy.,Laboratory of Genetic and Epigenetic Control of Gene Expression, Division of Biomedical Research, Department of Theoretical and Applied Sciences, University of Insubria, Busto Arsizio, 21052 Varese, Italy
| | - Davide Pozzi
- Laboratory of Pharmacology and Brain Pathology, Humanitas Clinical and Research Center, Rozzano, 20089 Milan, Italy
| | - Riccardo Lorenzo Rossi
- Istituto Nazionale di Genetica Molecolare "Romeo ed Enrica Invernizzi", 20122 Milan, Italy
| | - Linda Scaramuzza
- San Raffaele Rett Research Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Grazisa Rossetti
- Istituto Nazionale di Genetica Molecolare "Romeo ed Enrica Invernizzi", 20122 Milan, Italy
| | - Massimiliano Pagani
- Istituto Nazionale di Genetica Molecolare "Romeo ed Enrica Invernizzi", 20122 Milan, Italy
| | - Charlotte Kilstrup-Nielsen
- Laboratory of Genetic and Epigenetic Control of Gene Expression, Division of Biomedical Research, Department of Theoretical and Applied Sciences, University of Insubria, Busto Arsizio, 21052 Varese, Italy
| | - Michela Matteoli
- Laboratory of Pharmacology and Brain Pathology, Humanitas Clinical and Research Center, Rozzano, 20089 Milan, Italy.,Dip di Biotecnologie Mediche e Medicina Traslazionale, Università di Milano, Milan, Italy
| | - Nicoletta Landsberger
- San Raffaele Rett Research Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy.,Laboratory of Genetic and Epigenetic Control of Gene Expression, Division of Biomedical Research, Department of Theoretical and Applied Sciences, University of Insubria, Busto Arsizio, 21052 Varese, Italy
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137
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Gigek CO, Chen ES, Ota VK, Maussion G, Peng H, Vaillancourt K, Diallo AB, Lopez JP, Crapper L, Vasuta C, Chen GG, Ernst C. A molecular model for neurodevelopmental disorders. Transl Psychiatry 2015; 5:e565. [PMID: 25966365 PMCID: PMC4471287 DOI: 10.1038/tp.2015.56] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 03/24/2015] [Indexed: 01/24/2023] Open
Abstract
Genes implicated in neurodevelopmental disorders (NDDs) important in cognition and behavior may have convergent function and several cellular pathways have been implicated, including protein translational control, chromatin modification, and synapse assembly and maintenance. Here, we test the convergent effects of methyl-CpG binding domain 5 (MBD5) and special AT-rich binding protein 2 (SATB2) reduced dosage in human neural stem cells (NSCs), two genes implicated in 2q23.1 and 2q33.1 deletion syndromes, respectively, to develop a generalized model for NDDs. We used short hairpin RNA stably incorporated into healthy neural stem cells to supress MBD5 and SATB2 expression, and massively parallel RNA sequencing, DNA methylation sequencing and microRNA arrays to test the hypothesis that a primary etiology of NDDs is the disruption of the balance of NSC proliferation and differentiation. We show that reduced dosage of either gene leads to significant overlap of gene-expression patterns, microRNA patterns and DNA methylation states with control NSCs in a differentiating state, suggesting that a unifying feature of 2q23.1 and 2q33.1 deletion syndrome may be a lack of regulation between proliferation and differentiation in NSCs, as we observed previously for TCF4 and EHMT1 suppression following a similar experimental paradigm. We propose a model of NDDs whereby the balance of NSC proliferation and differentiation is affected, but where the molecules that drive this effect are largely specific to disease-causing genetic variation. NDDs are diverse, complex and unique, but the optimal balance of factors that determine when and where neural stem cells differentiate may be a major feature underlying the diverse phenotypic spectrum of NDDs.
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Affiliation(s)
- C O Gigek
- Department of Psychiatry, McGill Group for Suicide Studies, McGill University, Montreal, QC, Canada
| | - E S Chen
- Department of Psychiatry, McGill Group for Suicide Studies, McGill University, Montreal, QC, Canada
| | - V K Ota
- Department of Psychiatry, McGill Group for Suicide Studies, McGill University, Montreal, QC, Canada
| | - G Maussion
- Department of Psychiatry, McGill Group for Suicide Studies, McGill University, Montreal, QC, Canada
| | - H Peng
- Department of Psychiatry, McGill Group for Suicide Studies, McGill University, Montreal, QC, Canada
| | - K Vaillancourt
- Department of Psychiatry, McGill Group for Suicide Studies, McGill University, Montreal, QC, Canada
| | - A B Diallo
- Department of Psychiatry, McGill Group for Suicide Studies, McGill University, Montreal, QC, Canada
| | - J P Lopez
- Department of Psychiatry, McGill Group for Suicide Studies, McGill University, Montreal, QC, Canada
| | - L Crapper
- Department of Psychiatry, McGill Group for Suicide Studies, McGill University, Montreal, QC, Canada
| | - C Vasuta
- Department of Psychiatry, McGill Group for Suicide Studies, McGill University, Montreal, QC, Canada
| | - G G Chen
- Department of Psychiatry, McGill Group for Suicide Studies, McGill University, Montreal, QC, Canada
| | - C Ernst
- Department of Psychiatry, McGill Group for Suicide Studies, McGill University, Montreal, QC, Canada,Douglas Hospital Research Institute, 6875 LaSalle Boulevard, Frank Common Building Room 2101.2 Verdun, QC, Canada H4H 1R3. E-mail:
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138
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Alpha-Linolenic Acid-Induced Increase in Neurogenesis is a Key Factor in the Improvement in the Passive Avoidance Task After Soman Exposure. Neuromolecular Med 2015; 17:251-69. [DOI: 10.1007/s12017-015-8353-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 04/11/2015] [Indexed: 02/01/2023]
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139
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Collybistin binds and inhibits mTORC1 signaling: a potential novel mechanism contributing to intellectual disability and autism. Eur J Hum Genet 2015; 24:59-65. [PMID: 25898924 DOI: 10.1038/ejhg.2015.69] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 01/27/2015] [Accepted: 03/10/2015] [Indexed: 12/19/2022] Open
Abstract
Protein synthesis regulation via mammalian target of rapamycin complex 1 (mTORC1) signaling pathway has key roles in neural development and function, and its dysregulation is involved in neurodevelopmental disorders associated with autism and intellectual disability. mTOR regulates assembly of the translation initiation machinery by interacting with the eukaryotic initiation factor eIF3 complex and by controlling phosphorylation of key translational regulators. Collybistin (CB), a neuron-specific Rho-GEF responsible for X-linked intellectual disability with epilepsy, also interacts with eIF3, and its binding partner gephyrin associates with mTOR. Therefore, we hypothesized that CB also binds mTOR and affects mTORC1 signaling activity in neuronal cells. Here, by using induced pluripotent stem cell-derived neural progenitor cells from a male patient with a deletion of entire CB gene and from control individuals, as well as a heterologous expression system, we describe that CB physically interacts with mTOR and inhibits mTORC1 signaling pathway and protein synthesis. These findings suggest that disinhibited mTORC1 signaling may also contribute to the pathological process in patients with loss-of-function variants in CB.
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140
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Wong M, Roper SN. Genetic animal models of malformations of cortical development and epilepsy. J Neurosci Methods 2015; 260:73-82. [PMID: 25911067 DOI: 10.1016/j.jneumeth.2015.04.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 04/03/2015] [Accepted: 04/08/2015] [Indexed: 12/31/2022]
Abstract
Malformations of cortical development constitute a variety of pathological brain abnormalities that commonly cause severe, medically-refractory epilepsy, including focal lesions, such as focal cortical dysplasia, heterotopias, and tubers of tuberous sclerosis complex, and diffuse malformations, such as lissencephaly. Although some cortical malformations result from environmental insults during cortical development in utero, genetic factors are increasingly recognized as primary pathogenic factors across the entire spectrum of malformations. Genes implicated in causing different cortical malformations are involved in a variety of physiological functions, but many are focused on regulation of cell proliferation, differentiation, and neuronal migration. Advances in molecular genetic methods have allowed the engineering of increasingly sophisticated animal models of cortical malformations and associated epilepsy. These animal models have identified some common mechanistic themes shared by a number of different cortical malformations, but also revealed the diversity and complexity of cellular and molecular mechanisms that lead to the development of the pathological lesions and resulting epileptogenesis.
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Affiliation(s)
- Michael Wong
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Steven N Roper
- Department of Neurosurgery, University of Florida, Gainesville, FL 32610, USA
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141
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Modulation of hippocampal neural plasticity by glucose-related signaling. Neural Plast 2015; 2015:657928. [PMID: 25977822 PMCID: PMC4419237 DOI: 10.1155/2015/657928] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 04/02/2015] [Accepted: 04/05/2015] [Indexed: 12/20/2022] Open
Abstract
Hormones and peptides involved in glucose homeostasis are emerging as important modulators of neural plasticity. In this regard, increasing evidence shows that molecules such as insulin, insulin-like growth factor-I, glucagon-like peptide-1, and ghrelin impact on the function of the hippocampus, which is a key area for learning and memory. Indeed, all these factors affect fundamental hippocampal properties including synaptic plasticity (i.e., synapse potentiation and depression), structural plasticity (i.e., dynamics of dendritic spines), and adult neurogenesis, thus leading to modifications in cognitive performance. Here, we review the main mechanisms underlying the effects of glucose metabolism on hippocampal physiology. In particular, we discuss the role of these signals in the modulation of cognitive functions and their potential implications in dysmetabolism-related cognitive decline.
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142
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Pani G. Neuroprotective effects of dietary restriction: Evidence and mechanisms. Semin Cell Dev Biol 2015; 40:106-14. [DOI: 10.1016/j.semcdb.2015.03.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/03/2015] [Accepted: 03/04/2015] [Indexed: 12/30/2022]
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143
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Curatolo P. Mechanistic target of rapamycin (mTOR) in tuberous sclerosis complex-associated epilepsy. Pediatr Neurol 2015; 52:281-9. [PMID: 25591831 DOI: 10.1016/j.pediatrneurol.2014.10.028] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 09/29/2014] [Accepted: 10/29/2014] [Indexed: 01/12/2023]
Abstract
BACKGROUND Tuberous sclerosis complex is a multiorgan disease resulting from a mutation of one of two TSC genes. The two gene products form a functional complex that regulates the mTOR signaling pathway (mTOR initially represented mammalian target of rapamycin, but increasingly the term mechanistic target of rapamycin is used to reflect the ubiquitous occurrence of mTOR). Epilepsy is the most common neurological symptom of tuberous sclerosis complex, occurring in 80% to 90% of affected individuals over the course of their lifetimes and causing significant morbidity and mortality. The mechanistic target of rapamycin (mTOR) signaling pathway is intricately involved in multiple cellular functions--including protein synthesis, cell growth and proliferation, and synaptic plasticity--which may influence neuronal excitability and precipitate epileptogenesis. Recent preclinical and clinical studies have increased interest in the potential role of mTOR inhibitors for the treatment of tuberous sclerosis complex-related epilepsy. METHODS Medline and PubMed database searches were used to identify relevant studies and other information on tuberous sclerosis complex-related epilepsies, the mTOR pathway, and current advances in treatment approaches. RESULTS Although current management strategies that provide symptomatic relief are effective at reducing the frequency of seizures in individuals with tuberous sclerosis complex, there is further room for the exploration of therapies that directly address hyperactive mTOR signaling--the underlying etiology of the disease. The role of the antiepileptic effect of mTOR inhibition was first demonstrated in knockout TSC1 mouse models. Additionally, several case studies demonstrated a positive effect on seizure frequency and severity in patients with pharmacoresistant epilepsy. In a phase 1/2 clinical trial with 28 patients, clinically relevant reduction in overall seizure frequency was documented in individuals treated with the mTOR inhibitor everolimus. In a phase 3 trial evaluating the role of everolimus in subependymal giant cell astrocytoma, seizures were a secondary end point. Because the median seizure frequency was zero in this study, the analysis was inconclusive. CONCLUSION Various preclinical models provide substantial evidence for the role of mTOR inhibition in the treatment of epilepsy in individuals with tuberous sclerosis complex. Preliminary clinical studies provide supportive evidence for a role of mTOR inhibition in the management of tuberous sclerosis complex-associated epilepsy and pave the way for new randomized placebo-controlled studies. This article reviews current treatment recommendations for the management of tuberous sclerosis complex-associated epilepsy as well as the rationale and evidence to support the use of mTOR inhibitors.
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Affiliation(s)
- Paolo Curatolo
- Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University of Rome, Rome, Italy.
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144
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Cambiaghi M, Magri L, Cursi M. Importance of EEG in validating the chronic effects of drugs: suggestions from animal models of epilepsy treated with rapamycin. Seizure 2015; 27:30-9. [PMID: 25891924 DOI: 10.1016/j.seizure.2015.02.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 02/12/2015] [Accepted: 02/15/2015] [Indexed: 11/29/2022] Open
Abstract
PURPOSE The development of new drugs for the treatment of epilepsy is a major challenge for modern neurology and its first steps demand basic research. Preclinical studies on animal models of epilepsy are mainly based on the analysis of brain electrical activity to detect seizures, when they are not just limited to behavioral tests like the Racine scale. METHODS In the present review, we discuss the importance of using time-locked video and EEG recordings (Video-EEG) coupled with behavioral tests as tools to monitor and analyze the effects of anti-epileptic drugs in pre-clinical research. Particularly, we focus on the utility of a multimodal approach based on EEG/behavioral analysis to study the beneficial effects of chronic rapamycin treatment as a potential anti-epileptogenic therapy for a broad spectrum of epilepsy, including both genetic (as in tuberous sclerosis complex) and acquired diseases. RESULTS Changes and synchronization of neuronal activity of different areas have been correlated with specific behavior in both physiological and pathological conditions. In the epileptic brain, during a seizure there is an abnormal activation of many cells all at once, altering different networks. CONCLUSION A multimodal approach based on video, EEG analysis and behavioral tests would be the best option in preclinical studies of epilepsy.
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Affiliation(s)
- Marco Cambiaghi
- Università degli Studi di Torino, Department of Neuroscience, Turin, Italy.
| | - Laura Magri
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Department of Genetics and Genomics, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States.
| | - Marco Cursi
- Clinical Neurophysiology Unit, Department of Neurology, Scientific Institute San Raffaele, Milan, Italy
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145
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Zhang L, Bartley CM, Gong X, Hsieh LS, Lin TV, Feliciano DM, Bordey A. MEK-ERK1/2-dependent FLNA overexpression promotes abnormal dendritic patterning in tuberous sclerosis independent of mTOR. Neuron 2015; 84:78-91. [PMID: 25277454 DOI: 10.1016/j.neuron.2014.09.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2014] [Indexed: 12/17/2022]
Abstract
Abnormal dendritic complexity is a shared feature of many neurodevelopmental disorders associated with neurological defects. Here, we found that the actin-crosslinking protein filamin A (FLNA) is overexpressed in tuberous sclerosis complex (TSC) mice, a PI3K-mTOR model of neurodevelopmental disease that is associated with abnormal dendritic complexity. Both under- and overexpression of FLNA in wild-type neurons led to more complex dendritic arbors in vivo, suggesting that an optimal level of FLNA expression is required for normal dendritogenesis. In Tsc1(null) neurons, knocking down FLNA in vivo prevented dendritic abnormalities. Surprisingly, FLNA overexpression in Tsc1(null) neurons was dependent on MEK1/2 but not mTOR activity, despite both pathways being hyperactive. In addition, increasing MEK-ERK1/2 activity led to dendritic abnormalities via FLNA, and decreasing MEK-ERK1/2 signaling in Tsc1(null) neurons rescued dendritic defects. These data demonstrate that altered FLNA expression increases dendritic complexity and contributes to pathologic dendritic patterning in TSC in an mTOR-independent, ERK1/2-dependent manner.
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Affiliation(s)
- Longbo Zhang
- Department of Neurosurgery, Xiangya Hospital, Central South University, 85 Xiangya Street, Changsha, 410008, China; Department of Neurosurgery and Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8082, USA
| | - Christopher M Bartley
- Department of Neurosurgery and Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8082, USA; Department of Neurobiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Xuan Gong
- Department of Neurosurgery, Xiangya Hospital, Central South University, 85 Xiangya Street, Changsha, 410008, China; Department of Neurosurgery and Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8082, USA
| | - Lawrence S Hsieh
- Department of Neurosurgery and Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8082, USA
| | - Tiffany V Lin
- Department of Neurosurgery and Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8082, USA
| | - David M Feliciano
- Department of Neurosurgery and Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8082, USA
| | - Angélique Bordey
- Department of Neurosurgery and Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8082, USA.
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146
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Hobbs RM, La HM, Mäkelä JA, Kobayashi T, Noda T, Pandolfi PP. Distinct germline progenitor subsets defined through Tsc2-mTORC1 signaling. EMBO Rep 2015; 16:467-80. [PMID: 25700280 DOI: 10.15252/embr.201439379] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 01/15/2015] [Indexed: 12/21/2022] Open
Abstract
Adult tissue maintenance is often dependent on resident stem cells; however, the phenotypic and functional heterogeneity existing within this self-renewing population is poorly understood. Here, we define distinct subsets of undifferentiated spermatogonia (spermatogonial progenitor cells; SPCs) by differential response to hyperactivation of mTORC1, a key growth-promoting pathway. We find that conditional deletion of the mTORC1 inhibitor Tsc2 throughout the SPC pool using Vasa-Cre promotes differentiation at the expense of self-renewal and leads to germline degeneration. Surprisingly, Tsc2 ablation within a subset of SPCs using Stra8-Cre did not compromise SPC function. SPC activity also appeared unaffected by Amh-Cre-mediated Tsc2 deletion within somatic cells of the niche. Importantly, we find that differentiation-prone SPCs have elevated mTORC1 activity when compared to SPCs with high self-renewal potential. Moreover, SPCs insensitive to Tsc2 deletion are preferentially associated with mTORC1-active committed progenitor fractions. We therefore delineate SPC subsets based on differential mTORC1 activity and correlated sensitivity to Tsc2 deletion. We propose that mTORC1 is a key regulator of SPC fate and defines phenotypically distinct SPC subpopulations with varying propensities for self-renewal and differentiation.
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Affiliation(s)
- Robin M Hobbs
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center Harvard Medical School, Boston, MA, USA Australian Regenerative Medicine Institute and Department of Anatomy and Developmental Biology Monash University, Clayton, VIC, Australia
| | - Hue M La
- Australian Regenerative Medicine Institute and Department of Anatomy and Developmental Biology Monash University, Clayton, VIC, Australia
| | - Juho-Antti Mäkelä
- Australian Regenerative Medicine Institute and Department of Anatomy and Developmental Biology Monash University, Clayton, VIC, Australia
| | - Toshiyuki Kobayashi
- Department of Pathology and Oncology, Juntendo University School of Medicine, Tokyo, Japan
| | - Tetsuo Noda
- Department of Cell Biology, JFCR Cancer Institute, Tokyo, Japan
| | - Pier Paolo Pandolfi
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center Harvard Medical School, Boston, MA, USA
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147
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Delaney SP, Julian LM, Stanford WL. The neural crest lineage as a driver of disease heterogeneity in Tuberous Sclerosis Complex and Lymphangioleiomyomatosis. Front Cell Dev Biol 2014; 2:69. [PMID: 25505789 PMCID: PMC4243694 DOI: 10.3389/fcell.2014.00069] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 11/02/2014] [Indexed: 12/20/2022] Open
Abstract
Lymphangioleiomyomatosis (LAM) is a rare neoplastic disease, best characterized by the formation of proliferative nodules that express smooth muscle and melanocytic antigens within the lung parenchyma, leading to progressive destruction of lung tissue and function. The pathological basis of LAM is associated with Tuberous Sclerosis Complex (TSC), a multi-system disorder marked by low-grade tumors in the brain, kidneys, heart, eyes, lung and skin, arising from inherited or spontaneous germ-line mutations in either of the TSC1 or TSC2 genes. LAM can develop either in a patient with TSC (TSC-LAM) or spontaneously (S-LAM), and it is clear that the majority of LAM lesions of both forms are characterized by an inactivating mutation in either TSC1 or TSC2, as in TSC. Despite this genetic commonality, there is considerable heterogeneity in the tumor spectrum of TSC and LAM patients, the basis for which is currently unknown. There is extensive clinical evidence to suggest that the cell of origin for LAM, as well as many of the TSC-associated tumors, is a neural crest cell, a highly migratory cell type with extensive multi-lineage potential. Here we explore the hypothesis that the types of tumors that develop and the tissues that are affected in TSC and LAM are dictated by the developmental timing of TSC gene mutations, which determines the identities of the affected cell types and the size of downstream populations that acquire a mutation. We further discuss the evidence to support a neural crest origin for LAM and TSC tumors, and propose approaches for generating humanized models of TSC and LAM that will allow cell of origin theories to be experimentally tested. Identifying the cell of origin and developing appropriate humanized models is necessary to truly understand LAM and TSC pathology and to establish effective and long-lasting therapeutic approaches for these patients.
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Affiliation(s)
- Sean P Delaney
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute Ottawa, ON, Canada ; Faculty of Graduate and Postdoctoral Studies, University of Ottawa Ottawa, ON, Canada ; Department of Cellular and Molecular Medicine, University of Ottawa Ottawa, ON, Canada
| | - Lisa M Julian
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute Ottawa, ON, Canada ; Faculty of Graduate and Postdoctoral Studies, University of Ottawa Ottawa, ON, Canada
| | - William L Stanford
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute Ottawa, ON, Canada ; Faculty of Graduate and Postdoctoral Studies, University of Ottawa Ottawa, ON, Canada ; Department of Cellular and Molecular Medicine, University of Ottawa Ottawa, ON, Canada ; Department of Biochemistry, Microbiology, and Immunology, University of Ottawa Ottawa, ON, Canada
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148
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Maiese K. Driving neural regeneration through the mammalian target of rapamycin. Neural Regen Res 2014; 9:1413-7. [PMID: 25317149 PMCID: PMC4192939 DOI: 10.4103/1673-5374.139453] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2014] [Indexed: 12/12/2022] Open
Abstract
Neurodegenerative disorders affect more than 30 million individuals throughout the world and lead to significant disability as well as death. These statistics will increase almost exponentially as the lifespan and age of individuals increase globally and individuals become more susceptible to acute disorders such as stroke as well as chronic diseases that involve cognitive loss, Alzheimer's disease, and Parkinson's disease. Current therapies for such disorders are effective only for a small subset of individuals or provide symptomatic relief but do not alter disease progression. One exciting therapeutic approach that may turn the tide for addressing neurodegenerative disorders involves the mammalian target of rapamycin (mTOR). mTOR is a component of the protein complexes mTOR Complex 1 (mTORC1) and mTOR Complex 2 (mTORC2) that are ubiquitous throughout the body and control multiple functions such as gene transcription, metabolism, cell survival, and cell senescence. mTOR through its relationship with phosphoinositide 3-kinase (PI 3-K) and protein kinase B (Akt) and multiple downstream signaling pathways such as p70 ribosomal S6 kinase (p70S6K) and proline rich Akt substrate 40 kDa (PRAS40) promotes neuronal cell regeneration through stem cell renewal and oversees critical pathways such as apoptosis, autophagy, and necroptosis to foster protection against neurodegenerative disorders. Targeting by mTOR of specific pathways that drive long-term potentiation, synaptic plasticity, and β-amyloid toxicity may offer new strategies for disorders such as stroke and Alzheimer's disease. Overall, mTOR is an essential neuroprotective pathway but must be carefully targeted to maximize clinical efficacy and eliminate any clinical toxic side effects.
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149
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Xie L, Choudhury GR, Wang J, Park Y, Liu R, Yuan F, Zhang CL, Yorio T, Jin K, Yang SH. Methylene blue promotes quiescence of rat neural progenitor cells. Front Cell Neurosci 2014; 8:315. [PMID: 25339866 PMCID: PMC4188130 DOI: 10.3389/fncel.2014.00315] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 09/18/2014] [Indexed: 12/03/2022] Open
Abstract
Neural stem cell-based treatment holds a new therapeutic opportunity for neurodegenerative disorders. Here, we investigated the effect of methylene blue on proliferation and differentiation of rat neural progenitor cells (NPCs) both in vitro and in vivo. We found that methylene blue inhibited proliferation and promoted quiescence of NPCs in vitro without affecting committed neuronal differentiation. Consistently, intracerebroventricular infusion of methylene blue significantly inhibited NPC proliferation at the subventricular zone (SVZ). Methylene blue inhibited mTOR signaling along with down-regulation of cyclins in NPCs in vitro and in vivo. In summary, our study indicates that methylene blue may delay NPC senescence through enhancing NPCs quiescence.
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Affiliation(s)
- Luokun Xie
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center Fort Worth, TX, USA
| | - Gourav R Choudhury
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center Fort Worth, TX, USA
| | - Jixian Wang
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center Fort Worth, TX, USA
| | - Yong Park
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center Fort Worth, TX, USA
| | - Ran Liu
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center Fort Worth, TX, USA
| | - Fang Yuan
- Department of Neurosurgery, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University Beijing, China
| | - Chun-Li Zhang
- Department of Molecular Biology, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - Thomas Yorio
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center Fort Worth, TX, USA
| | - Kunlin Jin
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center Fort Worth, TX, USA
| | - Shao-Hua Yang
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center Fort Worth, TX, USA ; Department of Neurosurgery, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University Beijing, China
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150
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Li Y, Wang C, Zhang G, Wang X, Duan R, Gao H, Peng T, Teng J, Jia Y. Role of autophagy and mTOR signaling in neural differentiation of bone marrow mesenchymal stem cells. Cell Biol Int 2014; 38:1337-43. [PMID: 24890505 DOI: 10.1002/cbin.10320] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 04/25/2014] [Indexed: 11/10/2022]
Affiliation(s)
- Yanfei Li
- Department of Neurology; First Affiliated Hospital, Zhengzhou University; Zhengzhou 450052 China
| | - Cuiqin Wang
- Department of Neurology; First Affiliated Hospital, Zhengzhou University; Zhengzhou 450052 China
| | - Guangyu Zhang
- Department of Neurology; First Affiliated Hospital, Zhengzhou University; Zhengzhou 450052 China
| | - Xiaohan Wang
- Department of Neurology; First Affiliated Hospital, Zhengzhou University; Zhengzhou 450052 China
| | - Ranran Duan
- Department of Neurology; First Affiliated Hospital, Zhengzhou University; Zhengzhou 450052 China
| | - Huili Gao
- Department of Neurology; First Affiliated Hospital, Zhengzhou University; Zhengzhou 450052 China
| | - Tao Peng
- Department of Neurology; First Affiliated Hospital, Zhengzhou University; Zhengzhou 450052 China
| | - Junfang Teng
- Department of Neurology; First Affiliated Hospital, Zhengzhou University; Zhengzhou 450052 China
| | - Yanjie Jia
- Department of Neurology; First Affiliated Hospital, Zhengzhou University; Zhengzhou 450052 China
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