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Garone C, De Giorgio F, Carli S. Mitochondrial metabolism in neural stem cells and implications for neurodevelopmental and neurodegenerative diseases. J Transl Med 2024; 22:238. [PMID: 38438847 PMCID: PMC10910780 DOI: 10.1186/s12967-024-05041-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 02/25/2024] [Indexed: 03/06/2024] Open
Abstract
Mitochondria are cytoplasmic organelles having a fundamental role in the regulation of neural stem cell (NSC) fate during neural development and maintenance.During embryonic and adult neurogenesis, NSCs undergo a metabolic switch from glycolytic to oxidative phosphorylation with a rise in mitochondrial DNA (mtDNA) content, changes in mitochondria shape and size, and a physiological augmentation of mitochondrial reactive oxygen species which together drive NSCs to proliferate and differentiate. Genetic and epigenetic modifications of proteins involved in cellular differentiation (Mechanistic Target of Rapamycin), proliferation (Wingless-type), and hypoxia (Mitogen-activated protein kinase)-and all connected by the common key regulatory factor Hypoxia Inducible Factor-1A-are deemed to be responsible for the metabolic shift and, consequently, NSC fate in physiological and pathological conditions.Both primary mitochondrial dysfunction due to mutations in nuclear DNA or mtDNA or secondary mitochondrial dysfunction in oxidative phosphorylation (OXPHOS) metabolism, mitochondrial dynamics, and organelle interplay pathways can contribute to the development of neurodevelopmental or progressive neurodegenerative disorders.This review analyses the physiology and pathology of neural development starting from the available in vitro and in vivo models and highlights the current knowledge concerning key mitochondrial pathways involved in this process.
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Affiliation(s)
- C Garone
- Department of Medical and Surgical Sciences, Alma Mater Studiorum-University of Bologna, Bologna, Italy.
- IRCCS Istituto Delle Scienze Neurologiche di Bologna, UO Neuropsichiatria Dell'età Pediatrica, Bologna, Italy.
| | - F De Giorgio
- Department of Medical and Surgical Sciences, Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | - S Carli
- Department of Medical and Surgical Sciences, Alma Mater Studiorum-University of Bologna, Bologna, Italy
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Sokolov AM, Aurich M, Bordey A. In Utero Electroporated Neurons for Medium-Throughput Screening of Compounds Regulating Neuron Morphology. eNeuro 2023; 10:ENEURO.0160-23.2023. [PMID: 37620147 PMCID: PMC10464655 DOI: 10.1523/eneuro.0160-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/27/2023] [Accepted: 07/27/2023] [Indexed: 08/26/2023] Open
Abstract
Several neurodevelopmental disorders are associated with increased mTOR activity that results in pathogenic neuronal dysmorphogenesis (i.e., soma and dendrite overgrowth), leading to circuit alterations associated with epilepsy and neurologic disabilities. Although an mTOR analog is approved for the treatment of epilepsy in one of these disorders, it has limited efficacy and is associated with a wide range of side effects. There is a need to develop novel agents for the treatment of mTOR-pathway related disorders. Here, we developed a medium-throughput phenotypic assay to test drug efficacy on neurite morphogenesis of mouse neurons in a hyperactive mTOR condition. Our assay involved in utero electroporation (IUE) of a selective population of cortical pyramidal neurons with a plasmid encoding the constitutively active mTOR activator, Rheb, and tdTomato. Labeled neurons from the somatosensory cortex (SSC) were cultured onto 96-well plates and fixed at various days in vitro or following Torin 1 treatment. Automated systems were used for image acquisition and neuron morphologic measurements. We validated our automated approach using traditional manual methods of neuron morphologic assessment. Both automated and manual analyses showed increased neurite length and complexity over time, and decreased neurite overgrowth and soma size with Torin 1. These data validate the accuracy of our automated approach that takes hours compared with weeks when using traditional manual methods. Taken together, this assay can be scaled to screen 32 compounds simultaneously in two weeks, highlighting its robustness and efficiency for medium-throughput screening of candidate therapeutics on a defined population of wild-type or diseased neurons.
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Affiliation(s)
- Aidan M Sokolov
- Departments of Neurosurgery, and Cellular and Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT 06520-8082
| | - Mariana Aurich
- Departments of Neurosurgery, and Cellular and Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT 06520-8082
| | - Angélique Bordey
- Departments of Neurosurgery, and Cellular and Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT 06520-8082
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3
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Kittock CM, Pilaz LJ. Advances in in utero electroporation. Dev Neurobiol 2023; 83:73-90. [PMID: 36861639 DOI: 10.1002/dneu.22910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/02/2023] [Accepted: 02/21/2023] [Indexed: 03/03/2023]
Abstract
In utero electroporation (IUE) is a technique developed in the early 2000s to transfect the neurons and neural progenitors of embryonic brains, thus enabling continued development in utero and subsequent analyses of neural development. Early IUE experiments focused on ectopic expression of plasmid DNA to analyze parameters such as neuron morphology and migration. Recent advances made in other fields, such as CRISPR/CAS9 genome editing, have been incorporated into IUE techniques as they were developed. Here, we provide a general review of the mechanics and techniques involved in IUE and explore the breadth of approaches that can be used in conjunction with IUE to study cortical development in a rodent model, with a focus on the novel advances in IUE techniques. We also highlight a few cases that exemplify the potential of IUE to study a broad range of questions in neural development.
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Affiliation(s)
- Claire M Kittock
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, South Dakota, USA
- Sanford School of Medicine, University of South Dakota, Sioux Falls, South Dakota, USA
| | - Louis-Jan Pilaz
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, South Dakota, USA
- Sanford School of Medicine, University of South Dakota, Sioux Falls, South Dakota, USA
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Riley VA, Holmberg JC, Sokolov AM, Feliciano DM. Tsc2 shapes olfactory bulb granule cell molecular and morphological characteristics. Front Mol Neurosci 2022; 15:970357. [PMID: 36277492 PMCID: PMC9581303 DOI: 10.3389/fnmol.2022.970357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
Tuberous Sclerosis Complex (TSC) is a neurodevelopmental disorder caused by mutations that inactivate TSC1 or TSC2. Hamartin and tuberin are encoded by TSC1 and TSC2 which form a GTPase activating protein heteromer that inhibits the Rheb GTPase from activating a growth promoting protein kinase called mammalian target of rapamycin (mTOR). Growths and lesions occur in the ventricular-subventricular zone (V-SVZ), cortex, olfactory tract, and olfactory bulbs (OB) in TSC. A leading hypothesis is that mutations in inhibitory neural progenitor cells cause brain growths in TSC. OB granule cells (GCs) are GABAergic inhibitory neurons that are generated through infancy by inhibitory progenitor cells along the V-SVZ. Removal of Tsc1 from mouse OB GCs creates cellular phenotypes seen in TSC lesions. However, the role of Tsc2 in OB GC maturation requires clarification. Here, it is demonstrated that conditional loss of Tsc2 alters GC development. A mosaic model of TSC was created by performing neonatal CRE recombinase electroporation into inhibitory V-SVZ progenitors yielded clusters of ectopic cytomegalic neurons with hyperactive mTOR complex 1 (mTORC1) in homozygous Tsc2 mutant but not heterozygous or wild type mice. Similarly, homozygous Tsc2 mutant GC morphology was altered at postnatal days 30 and 60. Tsc2 mutant GCs had hypertrophic dendritic arbors that were established by postnatal day 30. In contrast, loss of Tsc2 from mature GCs had negligible effects on mTORC1, soma size, and dendrite arborization. OB transcriptome profiling revealed a network of significantly differentially expressed genes following loss of Tsc2 during development that altered neural circuitry. These results demonstrate that Tsc2 has a critical role in regulating neural development and shapes inhibitory GC molecular and morphological characteristics.
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Cases-Cunillera S, van Loo KMJ, Pitsch J, Quatraccioni A, Sivalingam S, Salomoni P, Borger V, Dietrich D, Schoch S, Becker AJ. Heterogeneity and excitability of BRAF V600E-induced tumors is determined by Akt/mTOR-signaling state and Trp53-loss. Neuro Oncol 2021; 24:741-754. [PMID: 34865163 PMCID: PMC9071348 DOI: 10.1093/neuonc/noab268] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Background Developmental brain tumors harboring BRAFV600E somatic mutation are diverse. Here, we describe molecular factors that determine BRAFV600E-induced tumor biology and function. Methods Intraventricular in utero electroporation in combination with the piggyBac transposon system was utilized to generate developmental brain neoplasms, which were comprehensively analyzed with regard to growth using near-infrared in-vivo imaging, transcript signatures by RNA sequencing, and neuronal activity by multielectrode arrays. Results BRAF
V600E expression in murine neural progenitors elicits benign neoplasms composed of enlarged dysmorphic neurons and neoplastic astroglia recapitulating ganglioglioma (GG) only in concert with active Akt/mTOR-signaling. Purely glial tumors resembling aspects of polymorphous low-grade neuroepithelial tumors of the young (PLNTYs) emerge from BRAFV600E alone. Additional somatic Trp53-loss is sufficient to generate anaplastic GGs (aGGs) with glioneuronal clonality. Functionally, only BRAFV600E/pAkt tumors intrinsically generate substantial neuronal activity and show enhanced relay to adjacent tissue conferring high epilepsy propensity. In contrast, PLNTY- and aGG models lack significant spike activity, which appears in line with the glial differentiation of the former and a dysfunctional tissue structure combined with reduced neuronal transcript signatures in the latter. Conclusion mTOR-signaling and Trp53-loss critically determine the biological diversity and electrical activity of BRAFV600E-induced tumors.
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Affiliation(s)
- Silvia Cases-Cunillera
- Institute of Neuropathology, Section for Translational Epilepsy Research, Medical Faculty, University of Bonn, Bonn, Germany
| | - Karen M J van Loo
- Institute of Neuropathology, Section for Translational Epilepsy Research, Medical Faculty, University of Bonn, Bonn, Germany
- Department of Epileptology, Neurology, RWTH Aachen University, Aachen, Germany
| | - Julika Pitsch
- Department of Epileptology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Anne Quatraccioni
- Institute of Neuropathology, Section for Translational Epilepsy Research, Medical Faculty, University of Bonn, Bonn, Germany
| | - Sugirthan Sivalingam
- Institute of Neuropathology, Section for Translational Epilepsy Research, Medical Faculty, University of Bonn, Bonn, Germany
- Department of Human Genetics, Medical Faculty, University of Bonn, Bonn, Germany
| | - Paolo Salomoni
- Nuclear Function Group, German Centre for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Valeri Borger
- Department of Neurosurgery, University Hospital Bonn, Bonn, Germany
| | - Dirk Dietrich
- Department of Neurosurgery, University Hospital Bonn, Bonn, Germany
| | - Susanne Schoch
- Department of Epileptology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Albert J Becker
- Corresponding Author: Albert J. Becker, MD, Institute of Neuropathology, Section for Translational Epilepsy Research, Medical Faculty, University of Bonn, Venusberg-Campus 1, D-53127 Bonn, Germany ()
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Nguyen LH, Bordey A. Corrigendum: Convergent and Divergent Mechanisms of Epileptogenesis in mTORopathies. Front Neuroanat 2021; 15:715363. [PMID: 34295225 PMCID: PMC8290855 DOI: 10.3389/fnana.2021.715363] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 05/28/2021] [Indexed: 01/16/2023] Open
Affiliation(s)
- Lena H Nguyen
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Angélique Bordey
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
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Nguyen LH, Bordey A. Convergent and Divergent Mechanisms of Epileptogenesis in mTORopathies. Front Neuroanat 2021; 15:664695. [PMID: 33897381 PMCID: PMC8064518 DOI: 10.3389/fnana.2021.664695] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 03/17/2021] [Indexed: 12/30/2022] Open
Abstract
Hyperactivation of the mechanistic target of rapamycin complex 1 (mTORC1) due to mutations in genes along the PI3K-mTOR pathway and the GATOR1 complex causes a spectrum of neurodevelopmental disorders (termed mTORopathies) associated with malformation of cortical development and intractable epilepsy. Despite these gene variants’ converging impact on mTORC1 activity, emerging findings suggest that these variants contribute to epilepsy through both mTORC1-dependent and -independent mechanisms. Here, we review the literature on in utero electroporation-based animal models of mTORopathies, which recapitulate the brain mosaic pattern of mTORC1 hyperactivity, and compare the effects of distinct PI3K-mTOR pathway and GATOR1 complex gene variants on cortical development and epilepsy. We report the outcomes on cortical pyramidal neuronal placement, morphology, and electrophysiological phenotypes, and discuss some of the converging and diverging mechanisms responsible for these alterations and their contribution to epileptogenesis. We also discuss potential therapeutic strategies for epilepsy, beyond mTORC1 inhibition with rapamycin or everolimus, that could offer personalized medicine based on the gene variant.
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Affiliation(s)
- Lena H Nguyen
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Angélique Bordey
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
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Cheah PS, Prabhakar S, Yellen D, Beauchamp RL, Zhang X, Kasamatsu S, Bronson RT, Thiele EA, Kwiatkowski DJ, Stemmer-Rachamimov A, György B, Ling KH, Kaneki M, Tannous BA, Ramesh V, Maguire CA, Breakefield XO. Gene therapy for tuberous sclerosis complex type 2 in a mouse model by delivery of AAV9 encoding a condensed form of tuberin. SCIENCE ADVANCES 2021; 7:eabb1703. [PMID: 33523984 PMCID: PMC7793581 DOI: 10.1126/sciadv.abb1703] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 11/18/2020] [Indexed: 05/06/2023]
Abstract
Tuberous sclerosis complex (TSC) results from loss of a tumor suppressor gene - TSC1 or TSC2, encoding hamartin and tuberin, respectively. These proteins formed a complex to inhibit mTORC1-mediated cell growth and proliferation. Loss of either protein leads to overgrowth lesions in many vital organs. Gene therapy was evaluated in a mouse model of TSC2 using an adeno-associated virus (AAV) vector carrying the complementary for a "condensed" form of human tuberin (cTuberin). Functionality of cTuberin was verified in culture. A mouse model of TSC2 was generated by AAV-Cre recombinase disruption of Tsc2-floxed alleles at birth, leading to a shortened lifespan (mean 58 days) and brain pathology consistent with TSC. When these mice were injected intravenously on day 21 with AAV9-cTuberin, the mean survival was extended to 462 days with reduction in brain pathology. This demonstrates the potential of treating life-threatening TSC2 lesions with a single intravenous injection of AAV9-cTuberin.
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Affiliation(s)
- Pike-See Cheah
- Molecular Neurogenetics Unit, Department of Neurology and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, and Program in Neuroscience, Harvard Medical School, Boston, MA, USA
- Department of Human Anatomy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Malaysia
| | - Shilpa Prabhakar
- Molecular Neurogenetics Unit, Department of Neurology and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, and Program in Neuroscience, Harvard Medical School, Boston, MA, USA
| | - David Yellen
- Molecular Neurogenetics Unit, Department of Neurology and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, and Program in Neuroscience, Harvard Medical School, Boston, MA, USA
| | - Roberta L Beauchamp
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Xuan Zhang
- Molecular Neurogenetics Unit, Department of Neurology and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, and Program in Neuroscience, Harvard Medical School, Boston, MA, USA
| | - Shingo Kasamatsu
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
- Shriners Hospitals for Children, Boston, MA, USA
| | - Roderick T Bronson
- Rodent Histopathology Core Facility, Harvard Medical School, Boston, MA, USA
| | - Elizabeth A Thiele
- Herscot Center for Tuberous Sclerosis Complex, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- The Pediatric Epilepsy Program, Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | | | | | - Bence György
- Department of Neurobiology and Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA
- Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
- Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - King-Hwa Ling
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Malaysia
| | - Masao Kaneki
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
- Shriners Hospitals for Children, Boston, MA, USA
| | - Bakhos A Tannous
- Molecular Neurogenetics Unit, Department of Neurology and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, and Program in Neuroscience, Harvard Medical School, Boston, MA, USA
| | - Vijaya Ramesh
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Casey A Maguire
- Molecular Neurogenetics Unit, Department of Neurology and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, and Program in Neuroscience, Harvard Medical School, Boston, MA, USA
| | - Xandra O Breakefield
- Molecular Neurogenetics Unit, Department of Neurology and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, and Program in Neuroscience, Harvard Medical School, Boston, MA, USA.
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Zhang XY, Li J, Li CJ, Lin YQ, Huang CH, Zheng X, Song XC, Tu ZC, Li XJ, Yan S. Differential development and electrophysiological activity in cultured cortical neurons from the mouse and cynomolgus monkey. Neural Regen Res 2021; 16:2446-2452. [PMID: 33907033 PMCID: PMC8374592 DOI: 10.4103/1673-5374.313056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In vitro cultures of primary cortical neurons are widely used to investigate neuronal function. However, it has yet to be fully investigated whether there are significant differences in development and function between cultured rodent and primate cortical neurons, and whether these differences influence the utilization of cultured cortical neurons to model pathological conditions. Using in vitro culture techniques combined with immunofluorescence and electrophysiological methods, our study found that the development and maturation of primary cerebral cortical neurons from cynomolgus monkeys were slower than those from mice. We used a microelectrode array technique to compare the electrophysiological differences in cortical neurons, and found that primary cortical neurons from the mouse brain began to show electrical activity earlier than those from the cynomolgus monkey. Although cultured monkey cortical neurons developed slowly in vitro, they exhibited typical pathological features-revealed by immunofluorescent staining-when infected with adeno-associated viral vectors expressing mutant huntingtin (HTT), the Huntington's disease protein. A quantitative analysis of the cultured monkey cortical neurons also confirmed that mutant HTT significantly reduced the length of neurites. Therefore, compared with the primary cortical neurons of mice, cultured monkey cortical neurons have longer developmental and survival times and greater sustained physiological activity, such as electrophysiological activity. Our findings also suggest that primary cynomolgus monkey neurons cultured in vitro can simulate a cell model of human neurodegenerative disease, and may be useful for investigating time-dependent neuronal death as well as treatment via neuronal regeneration. All mouse experiments and protocols were approved by the Animal Care and Use Committee of Jinan University of China (IACUC Approval No. 20200512-04) on May 12, 2020. All monkey experiments were approved by the IACUC protocol (IACUC Approval No. LDACU 20190820-01) on August 23, 2019 for animal management and use.
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Affiliation(s)
- Xue-Yan Zhang
- Guangdong Key Laboratory of Non-Human Primate Models, Guangdong-Hongkong-Macau Institute of CNS Regeneration; Key Laboratory of CNS Regeneration, Ministry of Education, Jinan University, Guangzhou, Guangdong Province, China
| | - Jun Li
- Guangdong Key Laboratory of Non-Human Primate Models, Guangdong-Hongkong-Macau Institute of CNS Regeneration; Key Laboratory of CNS Regeneration, Ministry of Education, Jinan University, Guangzhou, Guangdong Province, China
| | - Cai-Juan Li
- Guangdong Key Laboratory of Non-Human Primate Models, Guangdong-Hongkong-Macau Institute of CNS Regeneration; Key Laboratory of CNS Regeneration, Ministry of Education, Jinan University, Guangzhou, Guangdong Province, China
| | - Ying-Qi Lin
- Guangdong Key Laboratory of Non-Human Primate Models, Guangdong-Hongkong-Macau Institute of CNS Regeneration; Key Laboratory of CNS Regeneration, Ministry of Education, Jinan University, Guangzhou, Guangdong Province, China
| | - Chun-Hui Huang
- Guangdong Key Laboratory of Non-Human Primate Models, Guangdong-Hongkong-Macau Institute of CNS Regeneration; Key Laboratory of CNS Regeneration, Ministry of Education, Jinan University, Guangzhou, Guangdong Province, China
| | - Xiao Zheng
- Guangdong Key Laboratory of Non-Human Primate Models, Guangdong-Hongkong-Macau Institute of CNS Regeneration; Key Laboratory of CNS Regeneration, Ministry of Education, Jinan University, Guangzhou, Guangdong Province, China
| | - Xi-Chen Song
- Guangdong Key Laboratory of Non-Human Primate Models, Guangdong-Hongkong-Macau Institute of CNS Regeneration; Key Laboratory of CNS Regeneration, Ministry of Education, Jinan University, Guangzhou, Guangdong Province, China
| | - Zhu-Chi Tu
- Guangdong Key Laboratory of Non-Human Primate Models, Guangdong-Hongkong-Macau Institute of CNS Regeneration; Key Laboratory of CNS Regeneration, Ministry of Education, Jinan University, Guangzhou, Guangdong Province, China
| | - Xiao-Jiang Li
- Guangdong Key Laboratory of Non-Human Primate Models, Guangdong-Hongkong-Macau Institute of CNS Regeneration; Key Laboratory of CNS Regeneration, Ministry of Education, Jinan University, Guangzhou, Guangdong Province, China
| | - Sen Yan
- Guangdong Key Laboratory of Non-Human Primate Models, Guangdong-Hongkong-Macau Institute of CNS Regeneration; Key Laboratory of CNS Regeneration, Ministry of Education, Jinan University, Guangzhou, Guangdong Province, China
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10
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Sokolov AM, Holmberg JC, Feliciano DM. The amino acid transporter Slc7a5 regulates the mTOR pathway and is required for granule cell development. Hum Mol Genet 2020; 29:3003-3013. [PMID: 32821949 PMCID: PMC7645712 DOI: 10.1093/hmg/ddaa186] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/03/2020] [Accepted: 08/15/2020] [Indexed: 12/11/2022] Open
Abstract
Pathogenic mutations in the solute carrier family 7 member 5 (SLC7A5) gene, which encodes an amino acid transporter cause microcephaly and seizures, yet the mechanisms responsible for these phenotypes are unclear. Models have demonstrated that Slc7a5 deletion is embryonic lethal and that these embryos lack a fully formed telencephalon. This phenotype is similar to that of mammalian target of rapamycin (mTOR) protein kinase deletion or mTOR inhibition. Notably, in many cells, Slc7a5 import of amino acids is required to maintain mTOR activity. Slc7a5 is present within neurogenic regions during embryogenesis, is found in cultured neurons and can modulate neuronal electrophysiological properties. However, Slc7a5 is also highly expressed within endothelial cells of the blood-brain barrier where removal in conditional mice leads to severe behavioral defects and non-cell autonomous changes in neurons. Therefore, the extent that neural Slc7a5 is required for development is unclear. Here, subventricular zone neural stem cells that generate olfactory bulb granule cell neurons were electroporated with SLC7A5 or Slc7a5 short hairpin RNA encoding plasmids. Although early phases of neural development were unaltered, Slc7a5 knockdown effected late phases of GC dendrite maturation and survival. Slc7a5 knockdown also decreased mTOR pathway activity. Ras homolog enriched in brain, an mTOR activator, rescued the effect of Slc7a5 knockdown on mTOR pathway activity and dendrite arbors. The data presented here demonstrate that Slc7a5 is required for GC mTOR pathway activity, maturation and survival, which may help explain why Slc7a5 mutations prevent normal brain development and function.
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Affiliation(s)
- Aidan M Sokolov
- Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314, USA
| | - Jennie C Holmberg
- Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314, USA
| | - David M Feliciano
- Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314, USA
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11
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Persistent Rheb-induced mTORC1 activation in spinal cord neurons induces hypersensitivity in neuropathic pain. Cell Death Dis 2020; 11:747. [PMID: 32920594 PMCID: PMC7487067 DOI: 10.1038/s41419-020-02966-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 08/21/2020] [Accepted: 08/31/2020] [Indexed: 12/21/2022]
Abstract
The small GTPase Ras homolog enriched in the brain (Rheb) can activate mammalian target of rapamycin (mTOR) and regulate the growth and cell cycle progression. We investigated the role of Rheb-mediated mTORC1 signaling in neuropathic pain. A chronic constriction injury (CCI) model was dopted. CCI induced obvious spinal Rheb expression and phosphorylation of mTOR, S6, and 4-E-BP1. Blocking mTORC1 signal with rapamycin alleviated the neuropathic pain and restored morphine efficacy in CCI model. Immunofluoresence showed a neuronal co-localization of CCI-induced Rheb and pS6. Rheb knockin mouse showed a similar behavioral phenotype as CCI. In spinal slice recording, CCI increased the firing frequency of neurons expressing HCN channels; inhibition of mTORC1 with rapamycin could reverse the increased spinal neuronal activity in neuropathic pain. Spinal Rheb is induced in neuropathic pain, which in turn active the mTORC1 signaling in CCI. Spinal Rheb-mTOR signal plays an important role in regulation of spinal sensitization in neuropathic pain, and targeting mTOR may give a new strategy for pain management.
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12
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Iffland PH, Barnes AE, Baybis M, Crino PB. Dynamic analysis of 4E-BP1 phosphorylation in neurons with Tsc2 or Depdc5 knockout. Exp Neurol 2020; 334:113432. [PMID: 32781001 DOI: 10.1016/j.expneurol.2020.113432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 07/13/2020] [Accepted: 08/04/2020] [Indexed: 12/15/2022]
Abstract
TSC1 or TSC2 mutations cause Tuberous Sclerosis Complex (TSC), and lead to mechanistic target of rapamycin (mTOR) hyperactivation evidenced by hyperphosphorylation of ribosomal S6 protein and 4-elongation factor binding protein 1 (4E-BP1). Amino acid (AA) levels modulate mTOR-dependent S6 and 4E-BP1 phosphorylation in non-neural cells, but this has not been comprehensively investigated in neurons. The effects of AA levels on mTOR signaling and S6 and 4E-BP1 phosphorylation were analyzed in Tsc2 and Depdc5 (a distinct mTOR regulatory gene associated with epilepsy) CRISPR-edited Neuro2a (N2a) cells and differentiated neurons. Tsc2 or Depdc5 knockout (KO) led to S6 and 4E-BP1 hyperphosphorylation and cell soma enlargement, but while Tsc2 KO N2a cells exhibited reduced S6 phosphorylation (Ser240/244) and cell soma size after incubation in AA free (AAF) media, Depdc5 KO cells did not. Using a CFP/YFP FRET-biosensor coupled to 4E-BP1, we assayed 4E-BP1 phosphorylation in living N2a cells and differentiated neurons following Tsc2 or Depdc5 KO. AAF conditions reduced 4E-BP1 phosphorylation in Tsc2 KO N2a cells but had no effect in Depdc5 KO cells. Rapamycin blocked S6 protein phosphorylation but had no effect on 4E-BP1 phosphorylation, following either Tsc2 or Depdc5 KO. Confocal imaging demonstrated that AAF media promoted movement of mTOR off the lysosome, functionally inactivating mTOR, in Tsc2 KO but not Depdc5 KO cells, demonstrating that AA levels modulate lysosomal mTOR localization and account, in part, for differential effects of AAF conditions following Tsc2 versus Depdc5 KO. AA levels and rapamycin differentially modulate S6 and 4E-BP1 phosphorylation and mTOR lysosomal localization in neurons following Tsc2 KO versus Depdc5 KO. Neuronal mTOR signaling in mTOR-associated epilepsies may have distinct responses to mTOR inhibitors and to levels of cellular amino acids.
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Affiliation(s)
- Philip H Iffland
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Allan E Barnes
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Marianna Baybis
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Peter B Crino
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States of America.
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13
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Salinas V, Vega P, Piccirilli MV, Chicco C, Ciraolo C, Christiansen S, Consalvo D, Perez-Maturo J, Medina N, González-Morón D, Novaro V, Perrone C, García MDC, Agosta G, Silva W, Kauffman M. Identification of a somatic mutation in the RHEB gene through high depth and ultra-high depth next generation sequencing in a patient with Hemimegalencephaly and drug resistant Epilepsy. Eur J Med Genet 2019; 62:103571. [DOI: 10.1016/j.ejmg.2018.11.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 10/18/2018] [Accepted: 11/04/2018] [Indexed: 10/27/2022]
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14
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Prabhakar S, Cheah PS, Zhang X, Zinter M, Gianatasio M, Hudry E, Bronson RT, Kwiatkowski DJ, Stemmer-Rachamimov A, Maguire CA, Sena-Esteves M, Tannous BA, Breakefield XO. Long-Term Therapeutic Efficacy of Intravenous AAV-Mediated Hamartin Replacement in Mouse Model of Tuberous Sclerosis Type 1. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2019; 15:18-26. [PMID: 31534984 PMCID: PMC6745533 DOI: 10.1016/j.omtm.2019.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 08/14/2019] [Indexed: 12/18/2022]
Abstract
Tuberous sclerosis complex (TSC) is a tumor suppressor syndrome caused by mutations in TSC1 or TSC2, encoding hamartin and tuberin, respectively. These proteins act as a complex that inhibits mammalian target of rapamycin (mTOR)-mediated cell growth and proliferation. Loss of either protein leads to overgrowth in many organs, including subependymal nodules, subependymal giant cell astrocytomas, and cortical tubers in the human brain. Neurological manifestations in TSC include intellectual disability, autism, hydrocephalus, and epilepsy. In a stochastic mouse model of TSC1 brain lesions, complete loss of Tsc1 is achieved in homozygous Tsc1-floxed mice in a subpopulation of neural cells in the brain by intracerebroventricular (i.c.v.) injection at birth of an adeno-associated virus (AAV) vector encoding Cre recombinase. This results in median survival of 38 days and brain pathology, including subependymal lesions and enlargement of neuronal cells. Remarkably, when these mice were injected intravenously on day 21 with an AAV9 vector encoding hamartin, most survived at least up to 429 days in apparently healthy condition with marked reduction in brain pathology. Thus, a single intravenous administration of an AAV vector encoding hamartin restored protein function in enough cells in the brain to extend lifespan in this TSC1 mouse model.
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Affiliation(s)
- Shilpa Prabhakar
- Molecular Neurogenetics Unit, Department of Neurology and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, and Neurodiscovery Center, Harvard Medical School, Charlestown, MA, USA
| | - Pike See Cheah
- Molecular Neurogenetics Unit, Department of Neurology and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, and Neurodiscovery Center, Harvard Medical School, Charlestown, MA, USA.,Department of Human Anatomy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Selangor, Malaysia
| | - Xuan Zhang
- Molecular Neurogenetics Unit, Department of Neurology and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, and Neurodiscovery Center, Harvard Medical School, Charlestown, MA, USA
| | - Max Zinter
- Molecular Neurogenetics Unit, Department of Neurology and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, and Neurodiscovery Center, Harvard Medical School, Charlestown, MA, USA
| | - Maria Gianatasio
- Department of Pathology, Massachusetts General Hospital, Boston, MA, USA
| | - Eloise Hudry
- Molecular Neurogenetics Unit, Department of Neurology and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, and Neurodiscovery Center, Harvard Medical School, Charlestown, MA, USA
| | - Roderick T Bronson
- Rodent Histopathology Core Facility, Harvard Medical School, Boston, MA, USA
| | | | | | - Casey A Maguire
- Molecular Neurogenetics Unit, Department of Neurology and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, and Neurodiscovery Center, Harvard Medical School, Charlestown, MA, USA
| | - Miguel Sena-Esteves
- Department of Neurology, Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA
| | - Bakhos A Tannous
- Molecular Neurogenetics Unit, Department of Neurology and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, and Neurodiscovery Center, Harvard Medical School, Charlestown, MA, USA
| | - Xandra O Breakefield
- Molecular Neurogenetics Unit, Department of Neurology and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital, and Neurodiscovery Center, Harvard Medical School, Charlestown, MA, USA
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15
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Qu L, Pan C, He SM, Lang B, Gao GD, Wang XL, Wang Y. The Ras Superfamily of Small GTPases in Non-neoplastic Cerebral Diseases. Front Mol Neurosci 2019; 12:121. [PMID: 31213978 PMCID: PMC6555388 DOI: 10.3389/fnmol.2019.00121] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/25/2019] [Indexed: 12/22/2022] Open
Abstract
The small GTPases from the Ras superfamily play crucial roles in basic cellular processes during practically the entire process of neurodevelopment, including neurogenesis, differentiation, gene expression, membrane and protein traffic, vesicular trafficking, and synaptic plasticity. Small GTPases are key signal transducing enzymes that link extracellular cues to the neuronal responses required for the construction of neuronal networks, as well as for synaptic function and plasticity. Different subfamilies of small GTPases have been linked to a number of non-neoplastic cerebral diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), intellectual disability, epilepsy, drug addiction, Huntington’s disease (HD), amyotrophic lateral sclerosis (ALS) and a large number of idiopathic cerebral diseases. Here, we attempted to make a clearer illustration of the relationship between Ras superfamily GTPases and non-neoplastic cerebral diseases, as well as their roles in the neural system. In future studies, potential treatments for non-neoplastic cerebral diseases which are based on small GTPase related signaling pathways should be explored further. In this paper, we review all the available literature in support of this possibility.
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Affiliation(s)
- Liang Qu
- Department of Neurosurgery, Tangdu Hospital, Air Force Military Medical University, Xi'an, China
| | - Chao Pan
- Beijing Institute of Biotechnology, Beijing, China
| | - Shi-Ming He
- Department of Neurosurgery, Tangdu Hospital, Air Force Military Medical University, Xi'an, China.,Department of Neurosurgery, Xi'an International Medical Center, Xi'an, China
| | - Bing Lang
- The School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom.,Department of Psychiatry, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Guo-Dong Gao
- Department of Neurosurgery, Tangdu Hospital, Air Force Military Medical University, Xi'an, China
| | - Xue-Lian Wang
- Department of Neurosurgery, Tangdu Hospital, Air Force Military Medical University, Xi'an, China
| | - Yuan Wang
- Department of Neurosurgery, Tangdu Hospital, Air Force Military Medical University, Xi'an, China
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16
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Role of mTOR Complexes in Neurogenesis. Int J Mol Sci 2018; 19:ijms19051544. [PMID: 29789464 PMCID: PMC5983636 DOI: 10.3390/ijms19051544] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/13/2018] [Accepted: 05/16/2018] [Indexed: 12/22/2022] Open
Abstract
Dysregulation of neural stem cells (NSCs) is associated with several neurodevelopmental disorders, including epilepsy and autism spectrum disorder. The mammalian target of rapamycin (mTOR) integrates the intracellular signals to control cell growth, nutrient metabolism, and protein translation. mTOR regulates many functions in the development of the brain, such as proliferation, differentiation, migration, and dendrite formation. In addition, mTOR is important in synaptic formation and plasticity. Abnormalities in mTOR activity is linked with severe deficits in nervous system development, including tumors, autism, and seizures. Dissecting the wide-ranging roles of mTOR activity during critical periods in development will greatly expand our understanding of neurogenesis.
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