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Binder MS, Escobar I, Xu Y, Sokolov AM, Zhang L, Bordey A. Reducing Filamin A Restores Cortical Synaptic Connectivity and Early Social Communication Following Cellular Mosaicism in Autism Spectrum Disorder Pathways. J Neurosci 2024; 44:e1245232024. [PMID: 39164108 PMCID: PMC11426378 DOI: 10.1523/jneurosci.1245-23.2024] [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: 07/05/2023] [Revised: 06/17/2024] [Accepted: 06/27/2024] [Indexed: 08/22/2024] Open
Abstract
Communication in the form of nonverbal, social vocalization, or crying is evolutionary conserved in mammals and is impaired early in human infants that are later diagnosed with autism spectrum disorder (ASD). Defects in infant vocalization have been proposed as an early sign of ASD that may exacerbate ASD development. However, the neural mechanisms associated with early communicative deficits in ASD are not known. Here, we expressed a constitutively active mutant of Rheb (RhebS16H), which is known to upregulate two ASD core pathways, mTOR complex 1 (mTORC1) and ERK1/2, in Layer (L) 2/3 pyramidal neurons of the neocortex of mice of either sex. We found that cellular mosaic expression of RhebS16H in L2/3 pyramidal neurons altered the production of isolation calls from neonatal mice. This was accompanied by an expected misplacement of neurons and dendrite overgrowth, along with an unexpected increase in spine density and length, which was associated with increased excitatory synaptic activity. This contrasted with the known decrease in spine density in RhebS16H neurons of 1-month-old mice. Reducing the levels of the actin cross-linking and adaptor protein filamin A (FLNA), known to be increased downstream of ERK1/2, attenuated dendrite overgrowth and fully restored spine properties, synaptic connectivity, and the production of pup isolation calls. These findings suggest that upper-layer cortical pyramidal neurons contribute to communicative deficits in a condition known to affect two core ASD pathways and that these mechanisms are regulated by FLNA.
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Affiliation(s)
- Matthew S Binder
- Departments of Neurosurgery, and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, Connecticut 06520-8082
| | - Iris Escobar
- Departments of Neurosurgery, and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, Connecticut 06520-8082
| | - Youfen Xu
- Departments of Neurosurgery, and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, Connecticut 06520-8082
| | - Aidan M Sokolov
- Departments of Neurosurgery, and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, Connecticut 06520-8082
| | - Longbo Zhang
- Departments of Neurosurgery, and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, Connecticut 06520-8082
| | - Angélique Bordey
- Departments of Neurosurgery, and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, Connecticut 06520-8082
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Sun X, Wang B, Ding L, Ding T, Wang Y, Xu M. Mmu_circ_0005373 and hsa_circ_0136255 participate in the pulmonary fibrosis of systemic sclerosis. Int Immunopharmacol 2024; 139:112690. [PMID: 39053227 DOI: 10.1016/j.intimp.2024.112690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 06/26/2024] [Accepted: 07/12/2024] [Indexed: 07/27/2024]
Abstract
The pathogenesis of SSc pulmonary fibrosis is complex and prognosis is poor. In order to find biomarkers to provide assistance in the diagnosis and treatment of systemic sclerosis (SSc), this study explored the role of SSc-related differentially expressed circRNAs in the fibrosis process. This study explored whether circular RNA (circRNA) mediated the mTOR signaling pathway by interacting with the eukaryotic translation initiation factor eIF4E-binding protein 1 (4E-BP1), participated in a competing endogenous RNA (ceRNA) network, and regulated the mechanism of pulmonary fibrosis in systemic sclerosis (SSc). The results showed that the expression of mmu_circ_0005373 was reduced, and mmu_circ_0005373 may regulate the mTOR signaling pathway by inhibiting the interacting with 4E-BP1 protein in the lung of SSc mice, and promote fibrosis in SSc. Hsa_circ_0136255, which is homologous to mmu_circ_0005373, is also reduced in SSc peripheral blood mononuclear cells, and predicted to interact with 4E-BP1 protein. Hsa_circ_0136255/hsa-miR-330-3p/TNFAIP3 ceRNA network had biological significance in SSc, and correlated with clinical data, including high-resolution CT, average expiratory flow at 25% vital capacity, neutrophil count, lymphocyte percentage, standard deviation of red blood cell distribution width, coefficient of variation of red blood cell distribution width, platelet distribution width, glutamic transaminase, γ-glutamyl transpeptidase, lymphocyte percentage, basophils percentage, red blood cell, plateletcrit, cholinesterase, and mean corpuscular hemoglobin concentration. Hsa_circ_0136255, hsa-miR-330-3p, and TNFAIP3 may be used as biomarkers for clinical diagnosis and treatment of SSc.
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Affiliation(s)
- Xiaolin Sun
- Department of Pediatrics, The Third People's Hospital of Longgang District, Shenzhen 518115, China; Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, National-Regional Key Technology Engineering Laboratory for Medical Ultrasound, School of Biomedical Engineering, Shenzhen University Medical School, Shenzhen 518060, China; South China Hospital, Medical School, Shenzhen University, Shenzhen 518111, China
| | - Baoyue Wang
- Key Autoimmunity Laboratory of Inner Mongolia, Department of Rheumatology, the First Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, Baotou 014010, China
| | - Lili Ding
- Key Autoimmunity Laboratory of Inner Mongolia, Department of Rheumatology, the First Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, Baotou 014010, China
| | - Tiantian Ding
- Key Autoimmunity Laboratory of Inner Mongolia, Department of Rheumatology, the First Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, Baotou 014010, China
| | - Yongfu Wang
- Key Autoimmunity Laboratory of Inner Mongolia, Department of Rheumatology, the First Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, Baotou 014010, China.
| | - Mingguo Xu
- Department of Pediatrics, The Third People's Hospital of Longgang District, Shenzhen 518115, China; Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, National-Regional Key Technology Engineering Laboratory for Medical Ultrasound, School of Biomedical Engineering, Shenzhen University Medical School, Shenzhen 518060, China; South China Hospital, Medical School, Shenzhen University, Shenzhen 518111, China.
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Cullen ER, Safari M, Mittelstadt I, Weston MC. Hyperactivity of mTORC1- and mTORC2-dependent signaling mediates epilepsy downstream of somatic PTEN loss. eLife 2024; 12:RP91323. [PMID: 38446016 PMCID: PMC10942640 DOI: 10.7554/elife.91323] [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: 03/07/2024] Open
Abstract
Gene variants that hyperactivate PI3K-mTOR signaling in the brain lead to epilepsy and cortical malformations in humans. Some gene variants associated with these pathologies only hyperactivate mTORC1, but others, such as PTEN, PIK3CA, and AKT, hyperactivate both mTORC1- and mTORC2-dependent signaling. Previous work established a key role for mTORC1 hyperactivity in mTORopathies, however, whether mTORC2 hyperactivity contributes is not clear. To test this, we inactivated mTORC1 and/or mTORC2 downstream of early Pten deletion in a new mouse model of somatic Pten loss-of-function (LOF) in the cortex and hippocampus. Spontaneous seizures and epileptiform activity persisted despite mTORC1 or mTORC2 inactivation alone, but inactivating both mTORC1 and mTORC2 simultaneously normalized brain activity. These results suggest that hyperactivity of both mTORC1 and mTORC2 can cause epilepsy, and that targeted therapies should aim to reduce activity of both complexes.
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Affiliation(s)
- Erin R Cullen
- Department of Neurological Sciences, Larner College of Medicine, University of VermontBurlingtonUnited States
| | - Mona Safari
- Fralin Biomedical Research Institute at VTC, Center for Neurobiology ResearchRoanokeUnited States
- Translational Biology, Medicine, and Health Graduate ProgramRoanokeUnited States
| | - Isabelle Mittelstadt
- Department of Neurological Sciences, Larner College of Medicine, University of VermontBurlingtonUnited States
| | - Matthew C Weston
- Department of Neurological Sciences, Larner College of Medicine, University of VermontBurlingtonUnited States
- Fralin Biomedical Research Institute at VTC, Center for Neurobiology ResearchRoanokeUnited States
- School of Neuroscience, Virginia Polytechnic and State UniversityBlacksburgUnited States
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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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Chen Y, Guan W, Wang ML, Lin XY. PI3K-AKT/mTOR Signaling in Psychiatric Disorders: A Valuable Target to Stimulate or Suppress? Int J Neuropsychopharmacol 2024; 27:pyae010. [PMID: 38365306 PMCID: PMC10888523 DOI: 10.1093/ijnp/pyae010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 02/08/2024] [Indexed: 02/18/2024] Open
Abstract
Economic development and increased stress have considerably increased the prevalence of psychiatric disorders in recent years, which rank as some of the most prevalent diseases globally. Several factors, including chronic social stress, genetic inheritance, and autogenous diseases, lead to the development and progression of psychiatric disorders. Clinical treatments for psychiatric disorders include psychotherapy, chemotherapy, and electric shock therapy. Although various achievements have been made researching psychiatric disorders, the pathogenesis of these diseases has not been fully understood yet, and serious adverse effects and resistance to antipsychotics are major obstacles to treating patients with psychiatric disorders. Recent studies have shown that the mammalian target of rapamycin (mTOR) is a central signaling hub that functions in nerve growth, synapse formation, and plasticity. The PI3K-AKT/mTOR pathway is a critical target for mediating the rapid antidepressant effects of these pharmacological agents in clinical and preclinical research. Abnormal PI3K-AKT/mTOR signaling is closely associated with the pathogenesis of several neurodevelopmental disorders. In this review, we focused on the role of mTOR signaling and the related aberrant neurogenesis in psychiatric disorders. Elucidating the neurobiology of the PI3K-AKT/mTOR signaling pathway in psychiatric disorders and its actions in response to antidepressants will help us better understand brain development and quickly identify new therapeutic targets for the treatment of these mental illnesses.
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Affiliation(s)
- Yan Chen
- Department of Neurology, Nantong Third People’s Hospital, Affiliated Nantong Hospital 3 of Nantong University, Nantong, Jiangsu, China
| | - Wei Guan
- Department of Pharmacology, Pharmacy College, Nantong University, Nantong, Jiangsu, China
| | - Mei-Lan Wang
- Department of Neurology, Nantong Third People’s Hospital, Affiliated Nantong Hospital 3 of Nantong University, Nantong, Jiangsu, China
| | - Xiao-Yun Lin
- Department of Neurology, Nantong Third People’s Hospital, Affiliated Nantong Hospital 3 of Nantong University, Nantong, Jiangsu, China
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6
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Cullen ER, Safari M, Mittelstadt I, Weston MC. Hyperactivity of mTORC1 and mTORC2-dependent signaling mediate epilepsy downstream of somatic PTEN loss. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.18.553856. [PMID: 37645923 PMCID: PMC10462128 DOI: 10.1101/2023.08.18.553856] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Gene variants that hyperactivate PI3K-mTOR signaling in the brain lead to epilepsy and cortical malformations in humans. Some gene variants associated with these pathologies only hyperactivate mTORC1, but others, such as PTEN, PIK3CA, and AKT, hyperactivate both mTORC1- and mTORC2-dependent signaling. Previous work established a key role for mTORC1 hyperactivity in mTORopathies, however, whether mTORC2 hyperactivity contributes is not clear. To test this, we inactivated mTORC1 and/or mTORC2 downstream of early Pten deletion in a new model of somatic Pten loss-of-function (LOF) in the cortex and hippocampus. Spontaneous seizures and epileptiform activity persisted despite mTORC1 or mTORC2 inactivation alone, but inactivating both mTORC1 and mTORC2 simultaneously normalized brain activity. These results suggest that hyperactivity of both mTORC1 and mTORC2 can cause epilepsy, and that targeted therapies should aim to reduce activity of both complexes.
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Affiliation(s)
- Erin R. Cullen
- Department of Neurological Sciences, Larner College of Medicine, University of Vermont, Burlington VT, 05405, USA
| | - Mona Safari
- Fralin Biomedical Research Institute at VTC, Center for Neurobiology Research, Roanoke VA, 24016, USA
| | - Isabelle Mittelstadt
- Department of Neurological Sciences, Larner College of Medicine, University of Vermont, Burlington VT, 05405, USA
| | - Matthew C. Weston
- Department of Neurological Sciences, Larner College of Medicine, University of Vermont, Burlington VT, 05405, USA
- Fralin Biomedical Research Institute at VTC, Center for Neurobiology Research, Roanoke VA, 24016, USA
- School of Neuroscience, Virginia Polytechnic and State University, Blacksburg VA, 24060, USA
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7
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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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Nguyen LH, Sharma M, Bordey A. 4E-BP1 expression in embryonic postmitotic neurons mitigates mTORC1-induced cortical malformations and behavioral seizure severity but does not prevent epilepsy in mice. Front Neurosci 2023; 17:1257056. [PMID: 37680968 PMCID: PMC10480503 DOI: 10.3389/fnins.2023.1257056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 07/31/2023] [Indexed: 09/09/2023] Open
Abstract
Hyperactivation of the mechanistic target of rapamycin complex 1 (mTORC1) pathway during neurodevelopment leads to focal cortical malformations associated with intractable seizures. Recent evidence suggests that dysregulated cap-dependent translation downstream of mTORC1 contributes to cytoarchitectural abnormalities and seizure activity. Here, we examined whether reducing cap-dependent translation by expressing a constitutively active form of the translational repressor, 4E-BP1, downstream of mTORC1 would prevent the development of cortical malformations and seizures. 4E-BP1CA was expressed embryonically either in radial glia (neural progenitor cells) that generate cortical layer 2/3 pyramidal neurons or in migrating neurons destined to layer 2/3 using a conditional expression system. In both conditions, 4E-BP1CA expression reduced mTORC1-induced neuronal hypertrophy and alleviated cortical mislamination, but a subset of ectopic neurons persisted in the deep layers and the white matter. Despite the above improvements, 4E-BP1CA expression in radial glia had no effects on seizure frequency and further exacerbated behavioral seizure severity associated with mTORC1 hyperactivation. In contrast, conditional 4E-BP1CA expression in migratory neurons mitigated the severity of behavioral seizures but the seizure frequency remained unchanged. These findings advise against targeting 4E-BPs by 4E-BP1CA expression during embryonic development for seizure prevention and suggest the presence of a development-dependent role for 4E-BPs in mTORC1-induced epilepsy.
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Affiliation(s)
- Lena H. Nguyen
- Department of Neuroscience, School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, United States
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT, United States
| | - Manas Sharma
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT, United States
| | - Angelique Bordey
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT, United States
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Zhao W, Xie C, Zhang X, Liu J, Liu J, Xia Z. Advances in the mTOR signaling pathway and its inhibitor rapamycin in epilepsy. Brain Behav 2023; 13:e2995. [PMID: 37221133 PMCID: PMC10275542 DOI: 10.1002/brb3.2995] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 03/15/2023] [Accepted: 03/22/2023] [Indexed: 05/25/2023] Open
Abstract
INTRODUCTION Epilepsy is one of the most common and serious brain syndromes and has adverse consequences on a patient's neurobiological, cognitive, psychological, and social wellbeing, thereby threatening their quality of life. Some patients with epilepsy experience poor treatment effects due to the unclear pathophysiological mechanisms of the syndrome. Dysregulation of the mammalian target of the rapamycin (mTOR) pathway is thought to play an important role in the onset and progression of some epilepsies. METHODS This review summarizes the role of the mTOR signaling pathway in the pathogenesis of epilepsy and the prospects for the use of mTOR inhibitors. RESULTS The mTOR pathway functions as a vital mediator in epilepsy development through diverse mechanisms, indicating that the it has great potential as an effective target for epilepsy therapy. The excessive activation of mTOR signaling pathway leads to structural changes in neurons, inhibits autophagy, exacerbates neuron damage, affects mossy fiber sprouting, enhances neuronal excitability, increases neuroinflammation, and is closely associated with tau upregulation in epilepsy. A growing number of studies have demonstrated that mTOR inhibitors exhibit significant antiepileptic effects in both clinical applications and animal models. Specifically, rapamycin, a specific inhibitor of TOR, reduces the intensity and frequency of seizures. Clinical studies in patients with tuberous sclerosis complex have shown that rapamycin has the function of reducing seizures and improving this disease. Everolimus, a chemically modified derivative of rapamycin, has been approved as an added treatment to other antiepileptic medicines. Further explorations are needed to evaluate the therapeutic efficacy and application value of mTOR inhibitors in epilepsy. CONCLUSIONS Targeting the mTOR signaling pathway provides a promising prospect for the treatment of epilepsy.
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Affiliation(s)
- Wei Zhao
- Department of GerontologyThe First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan HospitalJinanChina
| | - Cong Xie
- Department of GerontologyThe First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan HospitalJinanChina
| | - Xu Zhang
- Department of GerontologyThe First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan HospitalJinanChina
| | - Ju Liu
- Laboratory of Microvascular MedicineMedical Research CenterShandong Provincial Qianfoshan Hospital, Shandong UniversityJinanChina
| | - Jinzhi Liu
- Department of GerontologyThe First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan HospitalJinanChina
- Department of NeurologyLiaocheng People's Hospital and Liaocheng Clinical School of Shandong First Medical UniversityLiaochengChina
- Department of GerontologyCheeloo College of MedicineShandong Provincial Qianfoshan Hospital, Shandong UniversityJinanChina
- Department of Geriatric NeurologyThe First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan HospitalJinanChina
| | - Zhangyong Xia
- Department of NeurologyLiaocheng People's Hospital and Liaocheng Clinical School of Shandong First Medical UniversityLiaochengChina
- Department of NeurologyCheeloo College of MedicineLiaocheng People's Hospital, Shandong UniversityJinanChina
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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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11
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Zeng C, Hu J, Chen F, Huang T, Zhang L. The Coordination of mTOR Signaling and Non-Coding RNA in Regulating Epileptic Neuroinflammation. Front Immunol 2022; 13:924642. [PMID: 35898503 PMCID: PMC9310657 DOI: 10.3389/fimmu.2022.924642] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 06/16/2022] [Indexed: 11/13/2022] Open
Abstract
Epilepsy accounts for a significant proportion of the burden of neurological disorders. Neuroinflammation acting as the inflammatory response to epileptic seizures is characterized by aberrant regulation of inflammatory cells and molecules, and has been regarded as a key process in epilepsy where mTOR signaling serves as a pivotal modulator. Meanwhile, accumulating evidence has revealed that non-coding RNAs (ncRNAs) interfering with mTOR signaling are involved in neuroinflammation and therefore articipate in the development and progression of epilepsy. In this review, we highlight recent advances in the regulation of mTOR on neuroinflammatory cells and mediators, and feature the progresses of the interaction between ncRNAs and mTOR in epileptic neuroinflammation.
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Affiliation(s)
- Chudai Zeng
- Departments of Neurosurgery, and National Clinical Research Center of Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Jason Hu
- Department of Neonatology, Yale School of Medicine, New Haven, CT, United States
| | - Fenghua Chen
- Departments of Neurosurgery, and National Clinical Research Center of Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- *Correspondence: Fenghua Chen, ; Tianxiang Huang, ; Longbo Zhang,
| | - Tianxiang Huang
- Departments of Neurosurgery, and National Clinical Research Center of Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- *Correspondence: Fenghua Chen, ; Tianxiang Huang, ; Longbo Zhang,
| | - Longbo Zhang
- Departments of Neurosurgery, and National Clinical Research Center of Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, United States
- *Correspondence: Fenghua Chen, ; Tianxiang Huang, ; Longbo Zhang,
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Nguyen LH, Bordey A. Current Review in Basic Science: Animal Models of Focal Cortical Dysplasia and Epilepsy. Epilepsy Curr 2022; 22:234-240. [PMID: 36187145 PMCID: PMC9483763 DOI: 10.1177/15357597221098230] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Focal cortical dysplasia (FCD) is a malformation of cortical development that is a prevalent cause of intractable epilepsy in children. Of the three FCD subtypes, understanding the etiology and pathogenesis of FCD type II has seen the most progress owing to the recent advances in identifying gene mutations along the mTOR signaling pathway as a frequent cause of this disorder. Accordingly, numerous animal models of FCD type II based on genetic manipulation of the mTOR signaling pathway have emerged to investigate the mechanisms of epileptogenesis and novel therapeutics for epilepsy. These include transgenic and in utero electroporation-based animal models. Here, we review the histopathological and electroclinical features of existing FCD type II animal models and discuss the scientific and technical considerations, clinical applications, and limitations of current models. We also highlight other models of FCD based on early life acquired factors.
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Affiliation(s)
- Lena H. Nguyen
- Departments of Neurosurgery and Cellular & Molecular
Physiology, Yale University School of
Medicine, New Haven, CT, USA
| | - Angélique Bordey
- Departments of Neurosurgery and Cellular & Molecular
Physiology, Yale University School of
Medicine, New Haven, CT, USA
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13
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Wang G, Wu W, Xu Y, Yang Z, Xiao B, Long L. Imaging Genetics in Epilepsy: Current Knowledge and New Perspectives. Front Mol Neurosci 2022; 15:891621. [PMID: 35706428 PMCID: PMC9189397 DOI: 10.3389/fnmol.2022.891621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 05/06/2022] [Indexed: 12/11/2022] Open
Abstract
Epilepsy is a neurological network disease with genetics playing a much greater role than was previously appreciated. Unfortunately, the relationship between genetic basis and imaging phenotype is by no means simple. Imaging genetics integrates multidimensional datasets within a unified framework, providing a unique opportunity to pursue a global vision for epilepsy. This review delineates the current knowledge of underlying genetic mechanisms for brain networks in different epilepsy syndromes, particularly from a neural developmental perspective. Further, endophenotypes and their potential value are discussed. Finally, we highlight current challenges and provide perspectives for the future development of imaging genetics in epilepsy.
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Affiliation(s)
- Ge Wang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- Clinical Research Center for Epileptic Disease of Hunan Province, Central South University, Changsha, China
| | - Wenyue Wu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- Department of Neurology, The Second Affiliated Hospital of Nanchang University, Jiangxi, China
| | - Yuchen Xu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- Department of Neurology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Zhuanyi Yang
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- Clinical Research Center for Epileptic Disease of Hunan Province, Central South University, Changsha, China
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
| | - Bo Xiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- Clinical Research Center for Epileptic Disease of Hunan Province, Central South University, Changsha, China
| | - Lili Long
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- Clinical Research Center for Epileptic Disease of Hunan Province, Central South University, Changsha, China
- *Correspondence: Lili Long
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14
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Lee S, Lee JH. Brain somatic mutations as RNA therapeutic targets in neurological disorders. Ann N Y Acad Sci 2022; 1514:11-20. [PMID: 35527236 DOI: 10.1111/nyas.14786] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Research into the genetic etiology of a neurological disorder can provide directions for genetic diagnosis and targeted therapy. In the past, germline mutations, which are transmitted from parents or newly arise from parental germ cells, were considered as major genetic causes of neurological disorders. However, recent evidence has shown that somatic mutations in the brain, which can arise from neural stem cells during development or over aging, account for a significant number of brain disorders, ranging from neurodevelopmental, neurodegenerative, and neuropsychiatric to neoplastic disease. Moreover, the identification of disease-causing somatic mutations or mutated genes has provided new insights into molecular pathogenesis and unveiled potential therapeutic targets for treating neurological disorders that have few, or no, therapeutic options. RNA therapeutics, including antisense oligonucleotide (ASO) and small interfering RNA (siRNA), are emerging as promising therapeutic tools for treating genetic neurological disorders. As the number of approved and investigational ASO and siRNA drugs for neurological disorders associated with germline mutations increases, they may also prove to be attractive modalities for treating neurologic disorders resulting from somatic mutations. In this perspective, we highlight several neurological diseases caused by brain somatic mutations and discuss the potential role of RNA therapeutics in these conditions.
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Affiliation(s)
- Sungyul Lee
- SoVarGen Co., Ltd., Daejeon, Republic of Korea
| | - Jeong Ho Lee
- SoVarGen Co., Ltd., Daejeon, Republic of Korea.,Graduate School of Medical Science and Engineering, Korea Advanced Institute Science and Technology (KAIST), KAIST BioMedical Research Center, Daejeon, Republic of Korea
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15
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Genetic mosaicism in the human brain: from lineage tracing to neuropsychiatric disorders. Nat Rev Neurosci 2022; 23:275-286. [PMID: 35322263 DOI: 10.1038/s41583-022-00572-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2022] [Indexed: 12/18/2022]
Abstract
Genetic mosaicism is the result of the accumulation of somatic mutations in the human genome starting from the first postzygotic cell generation and continuing throughout the whole life of an individual. The rapid development of next-generation and single-cell sequencing technologies is now allowing the study of genetic mosaicism in normal tissues, revealing unprecedented insights into their clonal architecture and physiology. The somatic variant repertoire of an adult human neuron is the result of somatic mutations that accumulate in the brain by different mechanisms and at different rates during development and ageing. Non-pathogenic developmental mutations function as natural barcodes that once identified in deep bulk or single-cell sequencing can be used to retrospectively reconstruct human lineages. This approach has revealed novel insights into the clonal structure of the human brain, which is a mosaic of clones traceable to the early embryo that contribute differentially to the brain and distinct areas of the cortex. Some of the mutations happening during development, however, have a pathogenic effect and can contribute to some epileptic malformations of cortical development and autism spectrum disorder. In this Review, we discuss recent findings in the context of genetic mosaicism and their implications for brain development and disease.
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