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Kang K, Wu Y, Gan H, Yang B, Xiao H, Wang D, Qiu H, Dong X, Tang H, Zhai X. Pathophysiological mechanisms underlying the development of focal cortical dysplasia and their association with epilepsy: Experimental models as a research approach. Seizure 2024; 121:176-185. [PMID: 39191070 DOI: 10.1016/j.seizure.2024.08.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Revised: 08/16/2024] [Accepted: 08/16/2024] [Indexed: 08/29/2024] Open
Abstract
Focal cortical dysplasia (FCD) is a structural lesion that is the most common anatomical lesion identified in children, and the second most common in adults with drug-resistant focal-onset epilepsy. These lesions vary in size, location, and histopathological manifestations. FCDs are classified into three subtypes associated with loss-of-function mutations in PI3K/AKT, TSC1/TSC2, RHEB, and DEPDC/NPRL2/NPRL3. During the decades of research into FCD, experimental models have played an irreplaceable role in the research design of studies investigating disease pathogenesis, pathophysiology, and treatment. Further, the establishment of FCD experimental models has moved the field forward by (1) revealing the cellular processes and signaling pathways underlying FCD pathogenesis and (2) varying the methods and materials to study the function of FCD proteins. Currently, FCD experimental models are predominantly murine, with each model providing unique insights into FCD lesions. This review briefly summarizes the pathology and molecular functions of FCD, further comparing the available modeling methods and indexes, as well as the utilization of models, followed by an analysis of the similarities, advantages, and disadvantages between these models and human FCD.
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Affiliation(s)
- Kaiyi Kang
- Department of Neurosurgery, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Chongqing 400000, China
| | - Yuxin Wu
- Department of Neurosurgery, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Chongqing 400000, China
| | - Hui Gan
- Department of Neurosurgery, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Chongqing 400000, China
| | - Baohui Yang
- Department of Neurosurgery, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Chongqing 400000, China; Department of Neurosurgery, Laboratory of Neurosurgery, Institute of Neurology, Lanzhou University, Lanzhou 730000, China
| | - Han Xiao
- Department of Neurosurgery, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Chongqing 400000, China
| | - Difei Wang
- Department of Neurosurgery, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Chongqing 400000, China
| | - Hanli Qiu
- Department of Neurosurgery, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Chongqing 400000, China
| | - Xinyu Dong
- Department of Neurosurgery, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Chongqing 400000, China
| | - Haotian Tang
- Department of Neurosurgery, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Chongqing 400000, China
| | - Xuan Zhai
- Department of Neurosurgery, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Chongqing 400000, China.
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2
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Le Belle JE, Condro M, Cepeda C, Oikonomou KD, Tessema K, Dudley L, Schoenfield J, Kawaguchi R, Geschwind D, Silva AJ, Zhang Z, Shokat K, Harris NG, Kornblum HI. Acute rapamycin treatment reveals novel mechanisms of behavioral, physiological, and functional dysfunction in a maternal inflammation mouse model of autism and sensory over-responsivity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.08.602602. [PMID: 39026891 PMCID: PMC11257517 DOI: 10.1101/2024.07.08.602602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Maternal inflammatory response (MIR) during early gestation in mice induces a cascade of physiological and behavioral changes that have been associated with autism spectrum disorder (ASD). In a prior study and the current one, we find that mild MIR results in chronic systemic and neuro-inflammation, mTOR pathway activation, mild brain overgrowth followed by regionally specific volumetric changes, sensory processing dysregulation, and social and repetitive behavior abnormalities. Prior studies of rapamycin treatment in autism models have focused on chronic treatments that might be expected to alter or prevent physical brain changes. Here, we have focused on the acute effects of rapamycin to uncover novel mechanisms of dysfunction and related to mTOR pathway signaling. We find that within 2 hours, rapamycin treatment could rapidly rescue neuronal hyper-excitability, seizure susceptibility, functional network connectivity and brain community structure, and repetitive behaviors and sensory over-responsivity in adult offspring with persistent brain overgrowth. These CNS-mediated effects are also associated with alteration of the expression of several ASD-,ion channel-, and epilepsy-associated genes, in the same time frame. Our findings suggest that mTOR dysregulation in MIR offspring is a key contributor to various levels of brain dysfunction, including neuronal excitability, altered gene expression in multiple cell types, sensory functional network connectivity, and modulation of information flow. However, we demonstrate that the adult MIR brain is also amenable to rapid normalization of these functional changes which results in the rescue of both core and comorbid ASD behaviors in adult animals without requiring long-term physical alterations to the brain. Thus, restoring excitatory/inhibitory imbalance and sensory functional network modularity may be important targets for therapeutically addressing both primary sensory and social behavior phenotypes, and compensatory repetitive behavior phenotypes.
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3
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Dhaliwal NK, Weng OY, Dong X, Bhattacharya A, Ahmed M, Nishimura H, Choi WWY, Aggarwal A, Luikart BW, Shu Q, Li X, Wilson MD, Moffat J, Wang LY, Muffat J, Li Y. Synergistic hyperactivation of both mTORC1 and mTORC2 underlies the neural abnormalities of PTEN-deficient human neurons and cortical organoids. Cell Rep 2024; 43:114173. [PMID: 38700984 DOI: 10.1016/j.celrep.2024.114173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 03/20/2024] [Accepted: 04/16/2024] [Indexed: 05/05/2024] Open
Abstract
Mutations in the phosphatase and tensin homolog (PTEN) gene are associated with severe neurodevelopmental disorders. Loss of PTEN leads to hyperactivation of the mechanistic target of rapamycin (mTOR), which functions in two distinct protein complexes, mTORC1 and mTORC2. The downstream signaling mechanisms that contribute to PTEN mutant phenotypes are not well delineated. Here, we show that pluripotent stem cell-derived PTEN mutant human neurons, neural precursors, and cortical organoids recapitulate disease-relevant phenotypes, including hypertrophy, electrical hyperactivity, enhanced proliferation, and structural overgrowth. PTEN loss leads to simultaneous hyperactivation of mTORC1 and mTORC2. We dissect the contribution of mTORC1 and mTORC2 by generating double mutants of PTEN and RPTOR or RICTOR, respectively. Our results reveal that the synergistic hyperactivation of both mTORC1 and mTORC2 is essential for the PTEN mutant human neural phenotypes. Together, our findings provide insights into the molecular mechanisms that underlie PTEN-related neural disorders and highlight novel therapeutic targets.
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Affiliation(s)
- Navroop K Dhaliwal
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Octavia Yifang Weng
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Program in Neurosciences and Mental Health, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Xiaoxue Dong
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou 310052, China; The Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310029, China
| | - Afrin Bhattacharya
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Mai Ahmed
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Haruka Nishimura
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Wendy W Y Choi
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada; Program in Genetics and Genome Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Aditi Aggarwal
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Bryan W Luikart
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Qiang Shu
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou 310052, China
| | - Xuekun Li
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou 310052, China; The Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310029, China
| | - Michael D Wilson
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada; Program in Genetics and Genome Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Jason Moffat
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada; Program in Genetics and Genome Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Lu-Yang Wang
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Julien Muffat
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Yun Li
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada.
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Nguyen LH, Xu Y, Nair M, Bordey A. The mTOR pathway genes MTOR, Rheb, Depdc5, Pten, and Tsc1 have convergent and divergent impacts on cortical neuron development and function. eLife 2024; 12:RP91010. [PMID: 38411613 PMCID: PMC10942629 DOI: 10.7554/elife.91010] [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] [Indexed: 02/28/2024] Open
Abstract
Brain somatic mutations in various components of the mTOR complex 1 (mTORC1) pathway have emerged as major causes of focal malformations of cortical development and intractable epilepsy. While these distinct gene mutations converge on excessive mTORC1 signaling and lead to common clinical manifestations, it remains unclear whether they cause similar cellular and synaptic disruptions underlying cortical network hyperexcitability. Here, we show that in utero activation of the mTORC1 activator genes, Rheb or MTOR, or biallelic inactivation of the mTORC1 repressor genes, Depdc5, Tsc1, or Pten in the mouse medial prefrontal cortex leads to shared alterations in pyramidal neuron morphology, positioning, and membrane excitability but different changes in excitatory synaptic transmission. Our findings suggest that, despite converging on mTORC1 signaling, mutations in different mTORC1 pathway genes differentially impact cortical excitatory synaptic activity, which may confer gene-specific mechanisms of hyperexcitability and responses to therapeutic intervention.
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Affiliation(s)
- Lena H Nguyen
- Department of Neuroscience, School of Behavioral and Brain Sciences, University of Texas at DallasRichardsonUnited States
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of MedicineNew HavenUnited States
| | - Youfen Xu
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of MedicineNew HavenUnited States
| | - Maanasi Nair
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of MedicineNew HavenUnited States
| | - Angelique Bordey
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of MedicineNew HavenUnited States
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5
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Nguyen LH, Xu Y, Nair M, Bordey A. The mTOR pathway genes mTOR, Rheb, Depdc5, Pten, and Tsc1 have convergent and divergent impacts on cortical neuron development and function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.11.553034. [PMID: 37609221 PMCID: PMC10441381 DOI: 10.1101/2023.08.11.553034] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Brain somatic mutations in various components of the mTOR complex 1 (mTORC1) pathway have emerged as major causes of focal malformations of cortical development and intractable epilepsy. While these distinct gene mutations converge on excessive mTORC1 signaling and lead to common clinical manifestations, it remains unclear whether they cause similar cellular and synaptic disruptions underlying cortical network hyperexcitability. Here, we show that in utero activation of the mTORC1 activators, Rheb or mTOR, or biallelic inactivation of the mTORC1 repressors, Depdc5, Tsc1, or Pten in mouse medial prefrontal cortex leads to shared alterations in pyramidal neuron morphology, positioning, and membrane excitability but different changes in excitatory synaptic transmission. Our findings suggest that, despite converging on mTORC1 signaling, mutations in different mTORC1 pathway genes differentially impact cortical excitatory synaptic activity, which may confer gene-specific mechanisms of hyperexcitability and responses to therapeutic intervention.
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Affiliation(s)
- Lena H. Nguyen
- Department Neuroscience, School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Youfen Xu
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Maanasi Nair
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Angelique Bordey
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT 06510, USA
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6
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Narvaiz DA, Nolan SO, Smith GD, Holley AJ, Reynolds CD, Blandin KJ, Nguyen PH, Tran DLK, Lugo JN. Rapamycin improves social and stereotypic behavior abnormalities induced by pre-mitotic neuronal subset specific Pten deletion. GENES, BRAIN, AND BEHAVIOR 2023:e12854. [PMID: 37376966 PMCID: PMC10393422 DOI: 10.1111/gbb.12854] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 06/15/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023]
Abstract
The mechanistic target of rapamycin (mTOR) pathway is a signaling system integral to neural growth and migration. In both patients and rodent models, mutations to the phosphatase and tensin homolog gene (PTEN) on chromosome 10 results in hyperactivation of the mTOR pathway, as well as seizures, intellectual disabilities and autistic behaviors. Rapamycin, an inhibitor of mTOR, can reverse the epileptic phenotype of neural subset specific Pten knockout (NS-Pten KO) mice, but its impact on behavior is not known. To determine the behavioral effects of rapamycin, male and female NS-Pten KO and wildtype (WT) mice were assigned as controls or administered 10 mg/kg of rapamycin for 2 weeks followed by behavioral testing. Rapamycin improved social behavior in both genotypes and stereotypic behaviors in NS-Pten KO mice. Rapamycin treatment resulted in a reduction of several measures of activity in the open field test in both genotypes. Rapamycin did not reverse the reduced anxiety behavior in KO mice. These data show the potential clinical use of mTOR inhibitors by showing its administration can reduce the production of autistic-like behaviors in NS-Pten KO mice.
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Affiliation(s)
- David A Narvaiz
- Department of Psychology and Neuroscience, Baylor University, Waco, Texas, USA
| | - Suzanne O Nolan
- Department of Psychology and Neuroscience, Baylor University, Waco, Texas, USA
| | - Gregory D Smith
- Institute of Biomedical Studies, Baylor University, Waco, Texas, USA
| | - Andrew J Holley
- Department of Psychology and Neuroscience, Baylor University, Waco, Texas, USA
| | - Conner D Reynolds
- Department of Psychology and Neuroscience, Baylor University, Waco, Texas, USA
| | - Katherine J Blandin
- Department of Psychology and Neuroscience, Baylor University, Waco, Texas, USA
| | - Phuoc H Nguyen
- Department of Psychology and Neuroscience, Baylor University, Waco, Texas, USA
| | - Doan L K Tran
- Department of Psychology and Neuroscience, Baylor University, Waco, Texas, USA
| | - Joaquin N Lugo
- Department of Psychology and Neuroscience, Baylor University, Waco, Texas, USA
- Institute of Biomedical Studies, Baylor University, Waco, Texas, USA
- Department of Biology, Baylor University, Waco, Texas, USA
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Cullen ER, Tariq K, Shore AN, Luikart BW, Weston MC. mTORC2 Inhibition Improves Morphological Effects of PTEN Loss, But Does Not Correct Synaptic Dysfunction or Prevent Seizures. J Neurosci 2023; 43:827-845. [PMID: 36526374 PMCID: PMC9899090 DOI: 10.1523/jneurosci.1354-22.2022] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 11/29/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Hyperactivation of PI3K/PTEN-mTOR signaling during neural development is associated with focal cortical dysplasia (FCD), autism, and epilepsy. mTOR can signal through two major hubs, mTORC1 and mTORC2, both of which are hyperactive following PTEN loss of function (LOF). Here, we tested the hypothesis that genetic inactivation of the mTORC2 complex via deletion of Rictor is sufficient to rescue morphologic and electrophysiological abnormalities in the dentate gyrus caused by PTEN loss, as well as generalized seizures. An established, early postnatal mouse model of PTEN loss in male and female mice showed spontaneous seizures that were not prevented by mTORC2 inactivation. This lack of rescue occurred despite the normalization or amelioration of many morphologic and electrophysiological phenotypes. However, increased excitatory connectivity proximal to dentate gyrus granule neuron somas was not normalized by mTORC2 inactivation. Further studies demonstrated that, although mTORC2 inactivation largely rescued the dendritic arbor overgrowth caused by PTEN LOF, it increased synaptic strength and caused additional impairments of presynaptic function. These results suggest that a constrained increase in excitatory connectivity and co-occurring synaptic dysfunction is sufficient to generate seizures downstream of PTEN LOF, even in the absence of characteristic changes in morphologic properties.SIGNIFICANCE STATEMENT Homozygous deletion of the Pten gene in neuronal subpopulations in the mouse serves as a valuable model of epilepsy caused by mTOR hyperactivation. To better understand the physiological mechanisms downstream of Pten loss that cause epilepsy, as well as the therapeutic potential of targeted gene therapies, we tested whether genetic inactivation of the mTORC2 complex could improve the cellular, synaptic, and in vivo effects of Pten loss in the dentate gyrus. We found that mTORC2 inhibition improved or rescued all morphologic effects of Pten loss in the dentate gyrus, but synaptic changes and seizures persisted. These data suggest that synaptic dysfunction can drive epilepsy caused by hyperactivation of PI3K/PTEN-mTOR, and that future therapies should focus on this mechanistic link.
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Affiliation(s)
- Erin R Cullen
- Department of Neurological Sciences, Larner College of Medicine, University of Vermont, Burlington, Vermont 05405
| | - Kamran Tariq
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire 03755
| | - Amy N Shore
- Department of Neurological Sciences, Larner College of Medicine, University of Vermont, Burlington, Vermont 05405
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia 24016
| | - Bryan W Luikart
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire 03755
| | - Matthew C Weston
- Department of Neurological Sciences, Larner College of Medicine, University of Vermont, Burlington, Vermont 05405
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia 24016
- School of Neuroscience, Virginia Polytechnic and State University, Blacksburg, Virginia 24061
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Kasahara Y, Nakashima H, Nakashima K. Seizure-induced hilar ectopic granule cells in the adult dentate gyrus. Front Neurosci 2023; 17:1150283. [PMID: 36937666 PMCID: PMC10017466 DOI: 10.3389/fnins.2023.1150283] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 02/13/2023] [Indexed: 03/06/2023] Open
Abstract
Epilepsy is a chronic neurological disorder characterized by hypersynchronous spontaneous recurrent seizures, and affects approximately 50 million people worldwide. Cumulative evidence has revealed that epileptogenic insult temporarily increases neurogenesis in the hippocampus; however, a fraction of the newly generated neurons are integrated abnormally into the existing neural circuits. The abnormal neurogenesis, including ectopic localization of newborn neurons in the hilus, formation of abnormal basal dendrites, and disorganization of the apical dendrites, rewires hippocampal neural networks and leads to the development of spontaneous seizures. The central roles of hilar ectopic granule cells in regulating hippocampal excitability have been suggested. In this review, we introduce recent findings about the migration of newborn granule cells to the dentate hilus after seizures and the roles of seizure-induced ectopic granule cells in the epileptic brain. In addition, we delineate possible intrinsic and extrinsic mechanisms underlying this abnormality. Finally, we suggest that the regulation of seizure-induced ectopic cells can be a promising target for epilepsy therapy and provide perspectives on future research directions.
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9
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Tariq K, Cullen E, Getz SA, Conching AK, Goyette AR, Prina ML, Wang W, Li M, Weston MC, Luikart BW. Disruption of mTORC1 rescues neuronal overgrowth and synapse function dysregulated by Pten loss. Cell Rep 2022; 41:111574. [PMID: 36323257 PMCID: PMC9743803 DOI: 10.1016/j.celrep.2022.111574] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 09/06/2022] [Accepted: 10/06/2022] [Indexed: 11/06/2022] Open
Abstract
Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a negative regulator of AKT/mTOR signaling pathway. Mutations in PTEN are found in patients with autism, epilepsy, or macrocephaly. In mouse models, Pten loss results in neuronal hypertrophy, hyperexcitability, seizures, and ASD-like behaviors. The underlying molecular mechanisms of these phenotypes are not well delineated. We determined which of the Pten loss-driven aberrations in neuronal form and function are orchestrated by downstream mTOR complex 1 (mTORC1). Rapamycin-mediated inhibition of mTORC1 prevented increase in soma size, migration, spine density, and dendritic overgrowth in Pten knockout dentate gyrus granule neurons. Genetic knockout of Raptor to disrupt mTORC1 complex formation blocked Pten loss-mediated neuronal hypertrophy. Electrophysiological recordings revealed that genetic disruption of mTORC1 rescued Pten loss-mediated increase in excitatory synaptic transmission. We have identified an essential role for mTORC1 in orchestrating Pten loss-driven neuronal hypertrophy and synapse formation.
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Affiliation(s)
- Kamran Tariq
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Erin Cullen
- Department of Neurological Sciences, University of Vermont, Burlington, VT 05405, USA
| | - Stephanie A. Getz
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Andie K.S. Conching
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Andrew R. Goyette
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Mackenzi L. Prina
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Wei Wang
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Meijie Li
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Matthew C. Weston
- Department of Neurological Sciences, University of Vermont, Burlington, VT 05405, USA,These authors contributed equally,Correspondence: (M.C.W.), (B.W.L.)
| | - Bryan W. Luikart
- Department of Molecular and Systems Biology, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA,These authors contributed equally,Lead contact,Correspondence: (M.C.W.), (B.W.L.)
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10
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Shao Y, Ge Q, Yang J, Wang M, Zhou Y, Guo JX, Zhu M, Shi J, Hu Y, Shen L, Chen Z, Li XM, Zhu JM, Zhang J, Duan S, Chen J. Pathological Networks Involving Dysmorphic Neurons in Type II Focal Cortical Dysplasia. Neurosci Bull 2022; 38:1007-1024. [PMID: 35235180 PMCID: PMC9468210 DOI: 10.1007/s12264-022-00828-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/24/2021] [Indexed: 10/19/2022] Open
Abstract
Focal cortical dysplasia (FCD) is one of the most common causes of drug-resistant epilepsy. Dysmorphic neurons are the major histopathological feature of type II FCD, but their role in seizure genesis in FCD is unclear. Here we performed whole-cell patch-clamp recording and morphological reconstruction of cortical principal neurons in postsurgical brain tissue from drug-resistant epilepsy patients. Quantitative analyses revealed distinct morphological and electrophysiological characteristics of the upper layer dysmorphic neurons in type II FCD, including an enlarged soma, aberrant dendritic arbors, increased current injection for rheobase action potential firing, and reduced action potential firing frequency. Intriguingly, the upper layer dysmorphic neurons received decreased glutamatergic and increased GABAergic synaptic inputs that were coupled with upregulation of the Na+-K+-Cl- cotransporter. In addition, we found a depolarizing shift of the GABA reversal potential in the CamKII-cre::PTENflox/flox mouse model of drug-resistant epilepsy, suggesting that enhanced GABAergic inputs might depolarize dysmorphic neurons. Thus, imbalance of synaptic excitation and inhibition of dysmorphic neurons may contribute to seizure genesis in type II FCD.
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Affiliation(s)
- Yijie Shao
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
- Department of Neurosurgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China
| | - Qianqian Ge
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jiachao Yang
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Mi Wang
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Yu Zhou
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jin-Xin Guo
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, 310058, China
| | - Mengyue Zhu
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jiachen Shi
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Yiqi Hu
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Li Shen
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, 310058, China
- Department of Orthopedic Surgery, School of Medicine, the Second Affiliated Hospital, Zhejiang University, Hangzhou, 310009, China
- Hangzhou Innovation Center, Zhejiang University, Hangzhou, 310058, China
| | - Zhong Chen
- Institute of Pharmacology & Toxicology, NHC and CAMS Key Laboratory of Medical Neurobiology, College of Pharmaceutical Sciences, School of Basic Medical Sciences, Zhejiang University, Hangzhou, 310058, China
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310058, China
| | - Xiao-Ming Li
- Center for Neuroscience and Department of Neurology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, Center for Brain Science and Brain-Inspired Intelligence, Joint Institute for Genetics and Genome Medicine between, Guangdong Hong Kong Macao Greater Bay Area, Zhejiang University and the University of Toronto, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jun-Ming Zhu
- Department of Neurosurgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China
| | - Jianmin Zhang
- Department of Neurosurgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China.
| | - Shumin Duan
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China.
| | - Jiadong Chen
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China.
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11
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Sathyanarayana SH, Saunders JA, Slaughter J, Tariq K, Chakrabarti R, Sadanandappa MK, Luikart BW, Bosco G. Pten heterozygosity restores neuronal morphology in fragile X syndrome mice. Proc Natl Acad Sci U S A 2022; 119:e2109448119. [PMID: 35394871 PMCID: PMC9169627 DOI: 10.1073/pnas.2109448119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 02/11/2022] [Indexed: 11/30/2022] Open
Abstract
Genetic studies of hippocampal granule neuron development have been used to elucidate cellular functions of Pten and Fmr1. While mutations in each gene cause neurodevelopmental disorders such as autism and fragile X syndrome, how Pten and Fmr1 function alone or together during normal development is not known. Moreover, Pten mRNA is bound by the fragile X mental retardation protein (FMRP) RNA binding protein, but how this physical interaction impinges on phosphatase and tensin homolog protein (PTEN) expression is not known. To understand the interaction of PTEN and FMRP, we investigated the dentate gyrus granule neuron development in Pten and Fmr1 knockout (KO) mice. Interestingly, heterozygosity of Pten restored Fmr1 KO cellular phenotypes, including dendritic arborization, and spine density, while PTEN protein expression was significantly increased in Fmr1 KO animals. However, complete deletion of both Pten and Fmr1 resulted in a dramatic increase in dendritic length, spine density, and spine length. In addition, overexpression of PTEN in Fmr1 KO Pten heterozygous background reduced dendritic length, arborization, spine density, and spine length including pS6 levels. Our findings suggest that PTEN levels are negatively regulated by FMRP, and some Fmr1 KO phenotypes are caused by dysregulation of PTEN protein. These observations provide evidence for the genetic interaction of PTEN and FMRP and a possible mechanistic basis for the pathogenesis of Fmr1-related fragile X neurodevelopmental disorders.
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Affiliation(s)
| | - Jasmine A. Saunders
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Jacob Slaughter
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Kamran Tariq
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Rajarshi Chakrabarti
- Department of Biochemistry and Cellular Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Madhumala K. Sadanandappa
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Bryan W. Luikart
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Giovanni Bosco
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
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12
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Tariq K, Luikart BW. Striking a balance: PIP 2 and PIP 3 signaling in neuronal health and disease. EXPLORATION OF NEUROPROTECTIVE THERAPY 2022; 1:86-100. [PMID: 35098253 PMCID: PMC8797975 DOI: 10.37349/ent.2021.00008] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Phosphoinositides are membrane phospholipids involved in a variety of cellular processes like growth, development, metabolism, and transport. This review focuses on the maintenance of cellular homeostasis of phosphatidylinositol 4,5-bisphosphate (PIP2), and phosphatidylinositol 3,4,5-trisphosphate (PIP3). The critical balance of these PIPs is crucial for regulation of neuronal form and function. The activity of PIP2 and PIP3 can be regulated through kinases, phosphatases, phospholipases and cholesterol microdomains. PIP2 and PIP3 carry out their functions either indirectly through their effectors activating integral signaling pathways, or through direct regulation of membrane channels, transporters, and cytoskeletal proteins. Any perturbations to the balance between PIP2 and PIP3 signaling result in neurodevelopmental and neurodegenerative disorders. This review will discuss the upstream modulators and downstream effectors of the PIP2 and PIP3 signaling, in the context of neuronal health and disease.
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Affiliation(s)
- Kamran Tariq
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Bryan W Luikart
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
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13
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Fujimoto A, Enoki H, Niimi K, Nozaki T, Baba S, Shibamoto I, Otsuki Y, Oanishi T. Epilepsy in patients with focal cortical dysplasia may be associated with autism spectrum disorder. Epilepsy Behav 2021; 120:107990. [PMID: 33957439 DOI: 10.1016/j.yebeh.2021.107990] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/08/2021] [Accepted: 04/08/2021] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Patients with epilepsy associated with focal cortical dysplasia (FCD) may be associated with autism spectrum disorder (ASD). Therefore, the purpose of this study was to compare surgically treated patients with epilepsy secondary to FCD and normal volunteers without epilepsy and to review the neuropathological findings of patients with FCD. METHODS This study involved 38 patients with medically intractable focal onset epileptic seizures who underwent epilepsy surgery (Group 1). All patients had epilepsy associated with FCD. These patients and 38 normal volunteers without epilepsy (Group 2) were administered the autism spectrum quotient (AQ) test, and the groups were compared. RESULTS The 38 patients in Group 1 included 16 females and 22 males (age range 20-60, mean age, 33.0; standard deviation (SD), 11.8 years). The normal volunteers in Group 2 included 22 females and 16 males (age range 20-57, mean age, 30.6 years; SD, 8.8 years). Total AQ scores were significantly higher in Group 1 than Group 2 (p = 0.027). Patients with FCD I showed a higher AQ score than those with FCD II in the AQ test (p ≤ 0.001). CONCLUSION Patients with epilepsy secondary to FCD were associated with higher ASD score than normal volunteers. This tendency was seen more strongly in patients with FCD I than FCD II.
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Affiliation(s)
- Ayataka Fujimoto
- Comprehensive Epilepsy Center, Seirei Hamamatsu General Hospital, Shizuoka, Japan; Seirei Christopher University, Shizuoka, Japan.
| | - Hideo Enoki
- Comprehensive Epilepsy Center, Seirei Hamamatsu General Hospital, Shizuoka, Japan
| | - Keiko Niimi
- Comprehensive Epilepsy Center, Seirei Hamamatsu General Hospital, Shizuoka, Japan
| | - Toshiki Nozaki
- Comprehensive Epilepsy Center, Seirei Hamamatsu General Hospital, Shizuoka, Japan
| | - Shimpei Baba
- Comprehensive Epilepsy Center, Seirei Hamamatsu General Hospital, Shizuoka, Japan
| | | | - Yoshiro Otsuki
- Department of Pathology, Seirei Hamamatsu General Hospital, Shizuoka, Japan
| | - Tohru Oanishi
- Comprehensive Epilepsy Center, Seirei Hamamatsu General Hospital, Shizuoka, Japan
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14
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Littlejohn EL, DeSana AJ, Williams HC, Chapman RT, Joseph B, Juras JA, Saatman KE. IGF1-Stimulated Posttraumatic Hippocampal Remodeling Is Not Dependent on mTOR. Front Cell Dev Biol 2021; 9:663456. [PMID: 34095131 PMCID: PMC8174097 DOI: 10.3389/fcell.2021.663456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 04/26/2021] [Indexed: 01/29/2023] Open
Abstract
Adult hippocampal neurogenesis is stimulated acutely following traumatic brain injury (TBI). However, many hippocampal neurons born after injury develop abnormally and the number that survive long-term is debated. In experimental TBI, insulin-like growth factor-1 (IGF1) promotes hippocampal neuronal differentiation, improves immature neuron dendritic arbor morphology, increases long-term survival of neurons born after TBI, and improves cognitive function. One potential downstream mediator of the neurogenic effects of IGF1 is mammalian target of rapamycin (mTOR), which regulates proliferation as well as axonal and dendritic growth in the CNS. Excessive mTOR activation is posited to contribute to aberrant plasticity related to posttraumatic epilepsy, spurring preclinical studies of mTOR inhibitors as therapeutics for TBI. The degree to which pro-neurogenic effects of IGF1 depend upon upregulation of mTOR activity is currently unknown. Using immunostaining for phosphorylated ribosomal protein S6, a commonly used surrogate for mTOR activation, we show that controlled cortical impact TBI triggers mTOR activation in the dentate gyrus in a time-, region-, and injury severity-dependent manner. Posttraumatic mTOR activation in the granule cell layer (GCL) and dentate hilus was amplified in mice with conditional overexpression of IGF1. In contrast, delayed astrocytic activation of mTOR signaling within the dentate gyrus molecular layer, closely associated with proliferation, was not affected by IGF1 overexpression. To determine whether mTOR activation is necessary for IGF1-mediated stimulation of posttraumatic hippocampal neurogenesis, wildtype and IGF1 transgenic mice received the mTOR inhibitor rapamycin daily beginning at 3 days after TBI, following pulse labeling with bromodeoxyuridine. Compared to wildtype mice, IGF1 overexpressing mice exhibited increased posttraumatic neurogenesis, with a higher density of posttrauma-born GCL neurons at 10 days after injury. Inhibition of mTOR did not abrogate IGF1-stimulated enhancement of posttraumatic neurogenesis. Rather, rapamycin treatment in IGF1 transgenic mice, but not in WT mice, increased numbers of cells labeled with BrdU at 3 days after injury that survived to 10 days, and enhanced the proportion of posttrauma-born cells that differentiated into neurons. Because beneficial effects of IGF1 on hippocampal neurogenesis were maintained or even enhanced with delayed inhibition of mTOR, combination therapy approaches may hold promise for TBI.
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Affiliation(s)
| | | | | | | | | | | | - Kathryn E. Saatman
- Department of Physiology, Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, United States
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15
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Karalis V, Bateup HS. Current Approaches and Future Directions for the Treatment of mTORopathies. Dev Neurosci 2021; 43:143-158. [PMID: 33910214 PMCID: PMC8440338 DOI: 10.1159/000515672] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 02/13/2021] [Indexed: 11/19/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR) is a kinase at the center of an evolutionarily conserved signaling pathway that orchestrates cell growth and metabolism. mTOR responds to an array of intra- and extracellular stimuli and in turn controls multiple cellular anabolic and catabolic processes. Aberrant mTOR activity is associated with numerous diseases, with particularly profound impact on the nervous system. mTOR is found in two protein complexes, mTOR complex 1 (mTORC1) and 2 (mTORC2), which are governed by different upstream regulators and have distinct cellular actions. Mutations in genes encoding for mTOR regulators result in a collection of neurodevelopmental disorders known as mTORopathies. While these disorders can affect multiple organs, neuropsychiatric conditions such as epilepsy, intellectual disability, and autism spectrum disorder have a major impact on quality of life. The neuropsychiatric aspects of mTORopathies have been particularly challenging to treat in a clinical setting. Current therapeutic approaches center on rapamycin and its analogs, drugs that are administered systemically to inhibit mTOR activity. While these drugs show some clinical efficacy, adverse side effects, incomplete suppression of mTOR targets, and lack of specificity for mTORC1 or mTORC2 may limit their utility. An increased understanding of the neurobiology of mTOR and the underlying molecular, cellular, and circuit mechanisms of mTOR-related disorders will facilitate the development of improved therapeutics. Animal models of mTORopathies have helped unravel the consequences of mTOR pathway mutations in specific brain cell types and developmental stages, revealing an array of disease-related phenotypes. In this review, we discuss current progress and potential future directions for the therapeutic treatment of mTORopathies with a focus on findings from genetic mouse models.
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Affiliation(s)
- Vasiliki Karalis
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
| | - Helen S Bateup
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, California, USA
- Chan Zuckerberg Biohub, San Francisco, California, USA
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16
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LaSarge CL, Pun RYK, Gu Z, Riccetti MR, Namboodiri DV, Tiwari D, Gross C, Danzer SC. mTOR-driven neural circuit changes initiate an epileptogenic cascade. Prog Neurobiol 2020; 200:101974. [PMID: 33309800 DOI: 10.1016/j.pneurobio.2020.101974] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/22/2020] [Accepted: 12/05/2020] [Indexed: 11/29/2022]
Abstract
Mutations in genes regulating mTOR pathway signaling are now recognized as a significant cause of epilepsy. Interestingly, these mTORopathies are often caused by somatic mutations, affecting variable numbers of neurons. To better understand how this variability affects disease phenotype, we developed a mouse model in which the mTOR pathway inhibitor Pten can be deleted from 0 to 40 % of hippocampal granule cells. In vivo, low numbers of knockout cells caused focal seizures, while higher numbers led to generalized seizures. Generalized seizures coincided with the loss of local circuit interneurons. In hippocampal slices, low knockout cell loads produced abrupt reductions in population spike threshold, while spontaneous excitatory postsynaptic currents and circuit level recurrent activity increased gradually with rising knockout cell load. Findings demonstrate that knockout cells load is a critical variable regulating disease phenotype, progressing from subclinical circuit abnormalities to electrobehavioral seizures with secondary involvement of downstream neuronal populations.
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Affiliation(s)
- Candi L LaSarge
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States; Center for Pediatric Neuroscience, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States
| | - Raymund Y K Pun
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States; Center for Pediatric Neuroscience, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States
| | - Zhiqing Gu
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States; Shanghai Children's Hospital, Shanghai, 200062, China
| | - Matthew R Riccetti
- Molecular and Developmental Biology Graduate Program, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States
| | - Devi V Namboodiri
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States
| | - Durgesh Tiwari
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Christina Gross
- Center for Pediatric Neuroscience, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States; Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States; Center for Pediatric Neuroscience, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States; Molecular and Developmental Biology Graduate Program, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States; Department of Anesthesia, University of Cincinnati, Cincinnati, OH, 45267, United States.
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17
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White AR, Tiwari D, MacLeod MC, Danzer SC, Gross C. PI3K isoform-selective inhibition in neuron-specific PTEN-deficient mice rescues molecular defects and reduces epilepsy-associated phenotypes. Neurobiol Dis 2020; 144:105026. [PMID: 32712265 DOI: 10.1016/j.nbd.2020.105026] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/13/2020] [Accepted: 07/20/2020] [Indexed: 01/16/2023] Open
Abstract
Epilepsy affects all ages, races, genders, and socioeconomic groups. In about one third of patients, epilepsy is uncontrolled with current medications, leaving a vast need for improved therapies. The causes of epilepsy are diverse and not always known but one gene mutated in a small subpopulation of patients is phosphatase and tensin homolog (PTEN). Moreover, focal cortical dysplasia, which constitutes a large fraction of refractory epilepsies, has been associated with signaling defects downstream of PTEN. So far, most preclinical attempts to reverse PTEN deficiency-associated neurological deficits have focused on mTOR, a signaling hub several steps downstream of PTEN. Phosphoinositide 3-kinases (PI3Ks), by contrast, are the direct enzymatic counteractors of PTEN, and thus may be alternative treatment targets. PI3K activity is mediated by four different PI3K catalytic isoforms. Studies in cancer, where PTEN is commonly mutated, have demonstrated that inhibition of only one isoform, p110β, reduces progression of PTEN-deficient tumors. Importantly, inhibition of a single PI3K isoform leaves critical functions of general PI3K signaling throughout the body intact. Here, we show that this disease mechanism-targeted strategy borrowed from cancer research rescues or ameliorates neuronal phenotypes in male and female mice with neuron-specific PTEN deficiency. These phenotypes include cell signaling defects, protein synthesis aberrations, seizures, and cortical dysplasia. Of note, p110β is also dysregulated and a promising treatment target in the intellectual disability Fragile X syndrome, pointing towards a shared biological mechanism that is therapeutically targetable in neurodevelopmental disorders of different etiologies. Overall, this work advocates for further assessment of p110β inhibition not only in PTEN deficiency-associated neurodevelopmental diseases but also other brain disorders characterized by defects in the PI3K/mTOR pathway.
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Affiliation(s)
- Angela R White
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Durgesh Tiwari
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, OH 45229, USA
| | - Molly C MacLeod
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Anesthesiology, University of Cincinnati College of Medicine, OH 45229, USA
| | - Christina Gross
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, OH 45229, USA.
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18
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Skelton PD, Stan RV, Luikart BW. The Role of PTEN in Neurodevelopment. MOLECULAR NEUROPSYCHIATRY 2020; 5:60-71. [PMID: 32399470 PMCID: PMC7206585 DOI: 10.1159/000504782] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 11/13/2019] [Indexed: 12/11/2022]
Abstract
PTEN is a lipid and protein phosphatase that regulates cell growth and survival. Mutations to PTEN are highly penetrant for autism spectrum disorder (ASD). Here, we briefly review the evidence linking PTEN mutations to ASD and the mouse models that have been used to study the role of PTEN in neurodevelopment. We then focus on the cellular phenotypes associated with PTEN loss in neurons, highlighting the role PTEN plays in neuronal proliferation, migration, survival, morphology, and plasticity.
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Affiliation(s)
- Patrick D. Skelton
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Radu V. Stan
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Bryan W. Luikart
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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19
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Pten loss results in inappropriate excitatory connectivity. Mol Psychiatry 2019; 24:1627-1640. [PMID: 30967683 PMCID: PMC6785382 DOI: 10.1038/s41380-019-0412-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 01/31/2019] [Accepted: 03/18/2019] [Indexed: 11/10/2022]
Abstract
Pten mutations are associated with autism spectrum disorder. Pten loss of function in neurons increases excitatory synaptic connectivity, contributing to an imbalance between excitation and inhibition. We aimed to determine whether Pten loss results in aberrant connectivity in neural circuits. We compared postnatally generated wild-type and Pten knockout granule neurons integrating into the dentate gyrus using a variety of methods to examine their connectivity. We found that postsynaptic Pten loss provides an advantage to dendritic spines in competition over a limited pool of presynaptic boutons. Retrograde monosynaptic tracing with rabies virus reveals that this results in synaptic contact with more presynaptic partners. Using independently excitable opsins to interrogate multiple inputs onto a single neuron, we found that excess connectivity is established indiscriminately from among glutamatergic afferents. Therefore, Pten loss results in inappropriate connectivity whereby neurons are coupled to a greater number of synaptic partners.
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20
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Impact of mTOR hyperactive neurons on the morphology and physiology of adjacent neurons: Do PTEN KO cells make bad neighbors? Exp Neurol 2019; 321:113029. [PMID: 31377403 DOI: 10.1016/j.expneurol.2019.113029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/23/2019] [Accepted: 07/31/2019] [Indexed: 01/18/2023]
Abstract
Hyperactivation of the mechanistic target of rapamycin (mTOR) pathway is associated with epilepsy, autism and brain growth abnormalities in humans. mTOR hyperactivation often results from developmental somatic mutations, producing genetic lesions and associated dysfunction in relatively restricted populations of neurons. Disrupted brain regions, such as those observed in focal cortical dysplasia, can contain a mix of normal and mutant cells. Mutant cells exhibit robust anatomical and physiological changes. Less clear, however, is whether adjacent, initially normal cells are affected by the presence of abnormal cells. To explore this question, we used a conditional, inducible mouse model approach to delete the mTOR negative regulator phosphatase and tensin homolog (PTEN) from <1% to >30% of hippocampal dentate granule cells. We then examined the morphology of PTEN-expressing granule cells located in the same dentate gyri as the knockout (KO) cells. Despite the development of spontaneous seizures in higher KO animals, and disease worsening with increasing age, the morphology and physiology of PTEN-expressing cells was only modestly affected. PTEN-expressing cells had smaller somas than cells from control animals, but other parameters were largely unchanged. These findings contrast with the behavior of PTEN KO cells, which show increasing dendritic extent with greater KO cell load. Together, the findings indicate that genetically normal neurons can exhibit relatively stable morphology and intrinsic physiology in the presence of nearby pathological neurons and systemic disease.
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21
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Botsali A, Caliskan E, Eşme P, Dündar Ö. Oral hamartomatous lesion of Cowden's disease treated with the combination of erbium:YAG laser and topical sirolimus. Dermatol Ther 2019; 32:e13002. [DOI: 10.1111/dth.13002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/08/2019] [Accepted: 06/18/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Ayşenur Botsali
- Faculty of Health Sciences, Department of Dermatology, Gülhane School of MedicineGülhane Training and Research Hospital Ankara Turkey
| | - Ercan Caliskan
- Faculty of Health Sciences, Department of Dermatology, Gülhane School of MedicineGülhane Training and Research Hospital Ankara Turkey
| | - Pelin Eşme
- Faculty of Health Sciences, Department of Dermatology, Gülhane School of MedicineGülhane Training and Research Hospital Ankara Turkey
| | - Özlem Dündar
- Faculty of Health Sciences, Department of Dermatology, Gülhane School of MedicineGülhane Training and Research Hospital Ankara Turkey
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22
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Arafa SR, LaSarge CL, Pun RYK, Khademi S, Danzer SC. Self-reinforcing effects of mTOR hyperactive neurons on dendritic growth. Exp Neurol 2019; 311:125-134. [PMID: 30268766 PMCID: PMC6263818 DOI: 10.1016/j.expneurol.2018.09.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 09/17/2018] [Accepted: 09/27/2018] [Indexed: 10/28/2022]
Abstract
Loss of the mTOR pathway negative regulator PTEN from hippocampal dentate granule cells leads to neuronal hypertrophy, increased dendritic branching and aberrant basal dendrite formation in animal models. Similar changes are evident in humans with mTOR pathway mutations. These genetic conditions are associated with autism, cognitive dysfunction and epilepsy. Interestingly, humans with mTOR pathway mutations often present with mosaic disruptions of gene function, producing lesions that range from focal cortical dysplasia to hemimegalanecephaly. Whether mTOR-mediated neuronal dysmorphogenesis is impacted by the number of affected cells, however, is not known. mTOR mutations can produce secondary comorbidities, including brain hypertrophy and seizures, which could exacerbate dysmorphogenesis among mutant cells. To determine whether the percentage or "load" of PTEN knockout granule cells impacts the morphological development of these same cells, we generated two groups of PTEN knockout mice. In the first, PTEN deletion rates were held constant, at about 5%, and knockout cell growth over time was assessed. Knockout cells exhibited significant dendritic growth between 7 and 18 weeks, demonstrating that aberrant dendritic growth continues even after the cells reach maturity. In the second group of mice, PTEN was deleted from 2 to 37% of granule cells to determine whether deletion rate was a factor in driving this continued growth. Multivariate analysis revealed that both age and knockout cell load contributed to knockout cell dendritic growth. Although the mechanism remains to be determined, these findings demonstrate that large numbers of mutant neurons can produce self-reinforcing effects on their own growth.
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Affiliation(s)
- Salwa R Arafa
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, United States; Department of Drug Development, James L Winkle College of Pharmacy, University of Cincinnati, OH 45267, United States
| | - Candi L LaSarge
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, United States
| | - Raymund Y K Pun
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, United States
| | - Shadi Khademi
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, United States
| | - Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, United States; Departments of Anesthesia and Pediatrics, University of Cincinnati, Cincinnati, OH 45267, United States.
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23
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Danzer SC. Contributions of Adult-Generated Granule Cells to Hippocampal Pathology in Temporal Lobe Epilepsy: A Neuronal Bestiary. Brain Plast 2018; 3:169-181. [PMID: 30151341 PMCID: PMC6091048 DOI: 10.3233/bpl-170056] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Hippocampal neurogenesis continues throughout life in mammals – including humans. During the development of temporal lobe epilepsy, newly-generated hippocampal granule cells integrate abnormally into the brain. Abnormalities include ectopic localization of newborn cells, de novo formation of abnormal basal dendrites, and disruptions of the apical dendritic tree. Changes in granule cell position and dendritic structure fundamentally alter the types of inputs these cells are able to receive, as well as the relative proportions of remaining inputs. Dendritic abnormalities also create new pathways for recurrent excitation in the hippocampus. These abnormalities are hypothesized to contribute to the development of epilepsy, and may underlie cognitive disorders associated with the disease as well. To test this hypothesis, investigators have used pharmacological and genetic strategies in animal models to alter neurogenesis rates, or ablate the newborn cells outright. While findings are mixed and many unanswered questions remain, numerous studies now demonstrate that ablating newborn granule cells can have disease modifying effects in epilepsy. Taken together, findings provide a strong rationale for continued work to elucidate the role of newborn granule cells in epilepsy: both to understand basic mechanisms underlying the disease, and as a potential novel therapy for epilepsy.
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Affiliation(s)
- Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Departments of Anesthesia and Pediatrics, University of Cincinnati, Cincinnati, OH, USA
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24
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Abstract
The mechanistic target of rapamycin (mTOR) is an important signaling hub that integrates environmental information regarding energy availability and stimulates anabolic molecular processes and cell growth. Abnormalities in this pathway have been identified in several syndromes in which autism spectrum disorder (ASD) is highly prevalent. Several studies have investigated mTOR signaling in developmental and neuronal processes that, when dysregulated, could contribute to the development of ASD. Although many potential mechanisms still remain to be fully understood, these associations are of great interest because of the clinical availability of mTOR inhibitors. Clinical trials evaluating the efficacy of mTOR inhibitors to improve neurodevelopmental outcomes have been initiated.
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Affiliation(s)
- Kellen D. Winden
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Darius Ebrahimi-Fakhari
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Mustafa Sahin
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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25
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Wang Q, Zhang S, Cheng J, Liu W, Hui X. Lhermitte-Duclos disease: Clinical study with long-term follow-up in a single institution. Clin Neurol Neurosurg 2017; 162:53-58. [DOI: 10.1016/j.clineuro.2017.09.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 08/29/2017] [Accepted: 09/08/2017] [Indexed: 10/18/2022]
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26
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Yang W, Li L, Huang X, Kan G, Lin L, Cheng J, Xu C, Sun W, Cong W, Zhao S, Cui S. Levels of Leydig cell autophagy regulate the fertility of male naked mole-rats. Oncotarget 2017; 8:98677-98690. [PMID: 29228719 PMCID: PMC5716759 DOI: 10.18632/oncotarget.22088] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 09/03/2017] [Indexed: 01/02/2023] Open
Abstract
Fertility is abolished in nonbreeding males in colonies of natal naked mole-rats (NMRs). Although spermatogenesis occurs in both breeding and nonbreeding male NMRs, the mechanisms underlying the differences in fertility between breeders and nonbreeders remain unexplored. In this study, a significant decrease in autophagy was observed in Leydig cells of the testis from nonbreeding male NMRs. This alteration was visualised as a significant decrease in the levels of autophagy-related gene 7 (Atg7), Atg5, microtubule-associated protein 1A/B light chain 3 (LC3-II/I) and the number of autophagosomes and an increase in P62 levels using Western blotting analyses. Furthermore, monodansylcadaverine (MDC) staining and Western blot analyses revealed that testosterone production decreased in nonbreeding male NMR Leydig cells, this decrease was associated with a reduction in autophagy. Primary Leydig cells from breeding and nonbreeding male NMRs were processed to investigate the effect of an autophagy inhibitor (3-MA, 3-methyladenine) or an autophagy activator (rapamycin) on testosterone production. Rapamycin induced an increase in testosterone production in NMR Leydig cells, whereas 3-MA had the opposite effect. Consequently, spermatogenesis, the weight of the testis, and androgen levels were dramatically reduced in nonbreeding male NMRs. While rapamycin treatment restored the fertility of nonbreeding male NMRs. Based on these results, inadequate autophagy correlates with a decrease in steroid production in nonbreeding male NMR Leydig cells, which may ultimately influence the spermatogenesis and fertilities of these animals.
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Affiliation(s)
- Wenjing Yang
- Laboratory Animal Center, Second Military Medical University, Shanghai, China
| | - Li Li
- Department of Training, Second Military Medical University, Shanghai, China
| | - Xiaofeng Huang
- Medical Record Department, Ministry of Information, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Guanghan Kan
- China Astronaut Research and Training Center, Beijing, China
| | - Lifang Lin
- Laboratory Animal Center, Second Military Medical University, Shanghai, China
| | - Jishuai Cheng
- Laboratory Animal Center, Second Military Medical University, Shanghai, China
| | - Chen Xu
- Laboratory Animal Center, Second Military Medical University, Shanghai, China
| | - Wei Sun
- Laboratory Animal Center, Second Military Medical University, Shanghai, China
| | - Wei Cong
- Laboratory Animal Center, Second Military Medical University, Shanghai, China
| | - Shanmin Zhao
- Laboratory Animal Center, Second Military Medical University, Shanghai, China
| | - Shufang Cui
- Laboratory Animal Center, Second Military Medical University, Shanghai, China
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27
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Lhermitte-Duclos Disease (Dysplastic Gangliocytoma of the Cerebellum) and Cowden Syndrome: Clinical Experience From a Single Institution with Long-Term Follow-Up. World Neurosurg 2017; 104:398-406. [DOI: 10.1016/j.wneu.2017.04.147] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 04/21/2017] [Accepted: 04/22/2017] [Indexed: 11/24/2022]
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28
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Yenkoyan K, Grigoryan A, Fereshetyan K, Yepremyan D. Advances in understanding the pathophysiology of autism spectrum disorders. Behav Brain Res 2017; 331:92-101. [DOI: 10.1016/j.bbr.2017.04.038] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 04/16/2017] [Accepted: 04/18/2017] [Indexed: 10/19/2022]
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29
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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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30
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Keppler-Noreuil KM, Parker VE, Darling TN, Martinez-Agosto JA. Somatic overgrowth disorders of the PI3K/AKT/mTOR pathway & therapeutic strategies. AMERICAN JOURNAL OF MEDICAL GENETICS. PART C, SEMINARS IN MEDICAL GENETICS 2016; 172:402-421. [PMID: 27860216 PMCID: PMC5592089 DOI: 10.1002/ajmg.c.31531] [Citation(s) in RCA: 171] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The phosphatidylinositol-3-kinase (PI3K)/AKT/mTOR signaling pathway plays an essential role in regulation of normal cell growth, metabolism, and survival. Somatic activating mutations in the PI3K/AKT/mTOR pathway are among the most common mutations identified in cancer, and have been shown to cause a spectrum of overgrowth syndromes including PIK3CA-Related Overgrowth Spectrum, Proteus syndrome, and brain overgrowth conditions. Clinical findings in these disorders may be isolated or multiple, including sporadic or mosaic overgrowth (adipose, skeletal, muscle, brain, vascular, or lymphatic), and skin abnormalities (including epidermal nevi, hyper-, and hypopigmented lesions), and have the potential risk of tumorigenesis. Key negative regulators of the PI3K-AKT signaling pathway include PTEN and TSC1/TSC2 and germline loss-of function mutations of these genes are established to cause PTEN Hamartoma Tumor Syndrome and Tuberous Sclerosis Complex. Mosaic forms of these conditions lead to increased activation of PI3K and mTOR at affected sites and there is phenotypic overlap between these conditions. All are associated with significant morbidity with limited options for treatment other than symptomatic therapies and surgeries. As dysregulation of the PI3K/AKT/mTOR pathway has been implicated in cancer, several small molecule inhibitors targeting different components of the PI3K/AKT/mTOR signaling pathway are under clinical investigation. The development of these therapies brings closer the prospect of targeting treatment for somatic PI3K/AKT/mTOR-related overgrowth syndromes. This review describes the clinical findings, gene function and pathogenesis of these mosaic overgrowth syndromes, and presents existing and future treatment strategies to reduce or prevent associated complications of these disorders. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Kim M. Keppler-Noreuil
- National Human Genome Research institute, National Institutes of Health, Bethesda, Maryland
| | - Victoria E.R. Parker
- The University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Cambridge, UK
| | - Thomas N. Darling
- Department of Dermatology, Uniformed Services University of Health Sciences, Bethesda, Maryland
| | - Julian A. Martinez-Agosto
- Department of Human Genetics, Division of Medical Genetics, Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, California
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31
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Gross C. Defective phosphoinositide metabolism in autism. J Neurosci Res 2016; 95:1161-1173. [PMID: 27376697 DOI: 10.1002/jnr.23797] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/26/2016] [Accepted: 06/01/2016] [Indexed: 12/12/2022]
Abstract
Phosphoinositides are essential components of lipid membranes and crucial regulators of many cellular functions, including signal transduction, vesicle trafficking, membrane receptor localization and activity, and determination of membrane identity. These functions depend on the dynamic and highly regulated metabolism of phosphoinositides and require finely balanced activity of specific phosphoinositide kinases and phosphatases. There is increasing evidence from genetic and functional studies that these enzymes are often dysregulated or mutated in autism spectrum disorders; in particular, phosphoinositide 3-kinases and their regulatory subunits appear to be affected frequently. Examples of autism spectrum disorders with defective phosphoinositide metabolism are fragile X syndrome and autism disorders associated with mutations in the phosphoinositide 3-phosphatase tensin homolog deleted on chromosome 10 (PTEN), but recent genetic analyses also suggest that select nonsyndromic, idiopathic forms of autism may have altered activity of phosphoinositide kinases and phosphatases. Isoform-specific inhibitors for some of the phosphoinositide kinases have already been developed for cancer research and treatment, and a few are being evaluated for use in humans. Altogether, this offers exciting opportunities to explore altered phosphoinositide metabolism as a therapeutic target in individuals with certain forms of autism. This review summarizes genetic and functional studies identifying defects in phosphoinositide metabolism in autism and related disorders, describes published preclinical work targeting phosphoinositide 3-kinases in neurological diseases, and discusses the opportunities and challenges ahead to translate these findings from animal models and human cells into clinical application in humans. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Christina Gross
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.,Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio
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