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Man A, Di Scipio M, Grewal S, Suk Y, Trinari E, Ejaz R, Whitney R. The Genetics of Tuberous Sclerosis Complex and Related mTORopathies: Current Understanding and Future Directions. Genes (Basel) 2024; 15:332. [PMID: 38540392 PMCID: PMC10970281 DOI: 10.3390/genes15030332] [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: 02/12/2024] [Revised: 03/02/2024] [Accepted: 03/02/2024] [Indexed: 06/14/2024] Open
Abstract
The mechanistic target of rapamycin (mTOR) pathway serves as a master regulator of cell growth, proliferation, and survival. Upregulation of the mTOR pathway has been shown to cause malformations of cortical development, medically refractory epilepsies, and neurodevelopmental disorders, collectively described as mTORopathies. Tuberous sclerosis complex (TSC) serves as the prototypical mTORopathy. Characterized by the development of benign tumors in multiple organs, pathogenic variants in TSC1 or TSC2 disrupt the TSC protein complex, a negative regulator of the mTOR pathway. Variants in critical domains of the TSC complex, especially in the catalytic TSC2 subunit, correlate with increased disease severity. Variants in less crucial exons and non-coding regions, as well as those undetectable with conventional testing, may lead to milder phenotypes. Despite the assumption of complete penetrance, expressivity varies within families, and certain variants delay disease onset with milder neurological effects. Understanding these genotype-phenotype correlations is crucial for effective clinical management. Notably, 15% of patients have no mutation identified by conventional genetic testing, with the majority of cases postulated to be caused by somatic TSC1/TSC2 variants which present complex diagnostic challenges. Advancements in genetic testing, prenatal screening, and precision medicine hold promise for changing the diagnostic and treatment paradigm for TSC and related mTORopathies. Herein, we explore the genetic and molecular mechanisms of TSC and other mTORopathies, emphasizing contemporary genetic methods in understanding and diagnosing the condition.
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Affiliation(s)
- Alice Man
- Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Matteo Di Scipio
- Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Shan Grewal
- Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Yujin Suk
- Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Elisabetta Trinari
- Division of Developmental Pediatrics, Department of Pediatrics, McMaster Children’s Hospital, Hamilton, ON L8N 3Z5, Canada
| | - Resham Ejaz
- Division of Genetics, Department of Pediatrics, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Robyn Whitney
- Division of Neurology, Department of Pediatrics, McMaster University, Hamilton, ON L8S 4L8, Canada
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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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Kagitani-Shimono K, Kato H, Soeda F, Iwatani Y, Mukai M, Ogawa K, Tominaga K, Nabatame S, Taniike M. Extension of microglial activation is associated with epilepsy and cognitive dysfunction in Tuberous sclerosis complex: A TSPO-PET study. Neuroimage Clin 2022; 37:103288. [PMID: 36521371 PMCID: PMC9758490 DOI: 10.1016/j.nicl.2022.103288] [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: 09/17/2022] [Revised: 12/07/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022]
Abstract
BACKGROUND AND OBJECTIVES Neuroinflammation contributes to the severity of various neurological disorders, including epilepsy. Tuberous sclerosis complex (TSC) is a condition that results in the overactivation of the mammalian target of rapamycin (mTOR) pathway, which has been linked to the activation of microglia responsible for neuroinflammation. To clarify the involvement of neuroinflammation in the neuropathophysiology of TSC, we performed a positron emission tomography (PET) study using the translocator protein (TSPO) radioligand, [11C] DPA713, and investigated microglial activation in relation to neurological manifestations, especially epilepsy and cognitive function. METHODS This cross-sectional study included 18 patients with TSC (6 in the no-seizure group, 6 in the refractory seizure group, and 6 in the mTOR-inhibitor [mTOR-i] group). All participants underwent [11C] DPA713-PET. PET results were superimposed with a 3D T2-weighted fluid-attenuated inversion-recovery (FLAIR) and T1-weighted image (T1WI) to evaluate the location of cortical tubers. Microglial activation was assessed using the standardized uptake value ratio (SUVr) of DPA713 binding. The volume ratio of the DPA713-positive area to the intracranial volume (volume ratio of DPA713/ICV) was calculated to evaluate the extent of microglial activation. A correlation analysis was performed to examine the relationship between volume ratio of DPA713/ICV and severity of epilepsy and cognitive function. RESULTS Most cortical tubers with hyperintensity on FLAIR and hypo- or isointensity on T1WI showed microglial activation. The extent of microglial activation was significantly greater in the refractory seizure group than in the no-seizure or mTOR-i groups (p < 0.001). The extent of microglial activation in subjects without mTOR-i treatment correlated positively with epilepsy severity (r = 0.822, P = 0.001) and negatively with cognitive function (r = -0.846, p = 0.001), but these correlations were not present in the mTOR-i group (r = 0.232, P = 0.658, r = 0.371, P = 0.469, respectively). CONCLUSION Neuroinflammation is associated with the severity of epilepsy and cognitive dysfunction in brains with TSC. mTOR-i may suppress the extent of neuroinflammation in TSC. Investigating the spread of microglial activation using TSPO-PET in these patients may help to predict the progression of neuropathy by assessing the degree of neuroinflammation and therefore be useful for determining how aggressive the treatment should be and in assessing the effectiveness of such treatment in patients with TSC.
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Affiliation(s)
- Kuriko Kagitani-Shimono
- Department of Child Development, United Graduate School of Child Development, Osaka University, Osaka, Japan; Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan.
| | - Hiroki Kato
- Department of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Fumihiko Soeda
- Department of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yoshiko Iwatani
- Department of Child Development, United Graduate School of Child Development, Osaka University, Osaka, Japan; Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Masashi Mukai
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Katsuhiro Ogawa
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Koji Tominaga
- Department of Child Development, United Graduate School of Child Development, Osaka University, Osaka, Japan; Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Shin Nabatame
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Masako Taniike
- Department of Child Development, United Graduate School of Child Development, Osaka University, Osaka, Japan; Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
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Lim HK, Yoon JH, Song M. Autism Spectrum Disorder Genes: Disease-Related Networks and Compensatory Strategies. Front Mol Neurosci 2022; 15:922840. [PMID: 35726297 PMCID: PMC9206533 DOI: 10.3389/fnmol.2022.922840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 05/17/2022] [Indexed: 11/16/2022] Open
Abstract
The mammalian brain comprises structurally and functionally distinct regions. Each of these regions has characteristic molecular mechanisms that mediate higher-order tasks, such as memory, learning, emotion, impulse, and motor control. Many genes are involved in neuronal signaling and contribute to normal brain development. Dysfunction of essential components of neural signals leads to various types of brain disorders. Autism spectrum disorder is a neurodevelopmental disorder characterized by social deficits, communication challenges, and compulsive repetitive behaviors. Long-term genetic studies have uncovered key genes associated with autism spectrum disorder, such as SH3 and multiple ankyrin repeat domains 3, methyl-CpG binding protein 2, neurexin 1, and chromodomain helicase DNA binding protein 8. In addition, disease-associated networks have been identified using animal models, and the understanding of the impact of these genes on disease susceptibility and compensation is deepening. In this review, we examine rescue strategies using key models of autism spectrum disorder.
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Affiliation(s)
- Hye Kyung Lim
- Department of Life Sciences, Yeungnam University, Gyeongsan, South Korea
| | - Jong Hyuk Yoon
- Neurodegenerative Diseases Research Group, Korea Brain Research Institute, Daegu, South Korea
| | - Minseok Song
- Department of Life Sciences, Yeungnam University, Gyeongsan, South Korea
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Genetic pathogenesis of the epileptogenic lesions in Tuberous Sclerosis Complex: Therapeutic targeting of the mTOR pathway. Epilepsy Behav 2022; 131:107713. [PMID: 33431351 DOI: 10.1016/j.yebeh.2020.107713] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 12/14/2020] [Accepted: 12/14/2020] [Indexed: 12/13/2022]
Abstract
Tuberous sclerosis complex (TSC) is a genetic multisystem disease due to the mutation in one of the two genes TSC1 and TSC2, affecting several organs and systems and carrying a significant risk of early onset and refractory seizures. The pathogenesis of this complex disorder is now well known, with most of TSC-related manifestations being a consequence of the overactivation of the mammalian Target of Rapamycin (mTOR) complex. The discovery of this underlying mechanism paved the way for the use of a class of drugs called mTOR inhibitors including rapamycin and everolimus and specifically targeting this pathway. Rapamycin has been widely used in different animal models of TSC-related epilepsy and proved to be able not only to suppress seizures but also to prevent the development of epilepsy, thus demonstrating an antiepileptogenic potential. In some models, it also showed some benefit on neuropsychiatric manifestations associated with TSC. Everolimus has recently been approved by the US Food and Drug Administration and the European Medical Agency for the treatment of refractory seizures associated with TSC starting from the age of 2 years. It demonstrated a clear benefit when compared to placebo on reducing the frequency of different seizure types and exerting a higher effect in younger children. In conclusion, mTOR cascade can be a potentially major cause of TSC-associated epilepsy and neurodevelopmental disability, and additional research should investigate if early suppression of abnormal mTOR signal with mTOR inhibitors before seizure onset can be a more efficient approach and an effective antiepileptogenic and disease-modifying strategy in infants with TSC.
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Antoine MW. Paradoxical Hyperexcitability in Disorders of Neurodevelopment. Front Mol Neurosci 2022; 15:826679. [PMID: 35571370 PMCID: PMC9102973 DOI: 10.3389/fnmol.2022.826679] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 03/14/2022] [Indexed: 01/29/2023] Open
Abstract
Autism Spectrum Disorder (ASD), Rett syndrome (RTT) and Angelman Syndrome (AS) are neurodevelopmental disorders (NDDs) that share several clinical characteristics, including displays of repetitive movements, developmental delays, language deficits, intellectual disability, and increased susceptibility to epilepsy. While several reviews address the biological basis of non-seizure-related ASD phenotypes, here, I highlight some shared biological mechanisms that may contribute to increased seizure susceptibility. I focus on genetic studies identifying the anatomical origin of the seizure phenotype in loss-of-function, monogenic, mouse models of these NDDs, combined with insights gained from complementary studies quantifying levels of synaptic excitation and inhibition. Epilepsy is characterized by a sudden, abnormal increase in synchronous activity within neuronal networks, that is posited to arise from excess excitation, largely driven by reduced synaptic inhibition. Primarily for this reason, elevated network excitability is proposed to underlie the causal basis for the ASD, RTT, and AS phenotypes. Although, mouse models of these disorders replicate aspects of the human condition, i.e., hyperexcitability discharges or seizures on cortical electroencephalograms, measures at the synaptic level often reveal deficits in excitatory synaptic transmission, rather than too much excitation. Resolving this apparent paradox has direct implications regarding expected outcomes of manipulating GABAergic tone. In particular, in NDDs associated with seizures, cortical circuits can display reduced, rather than normal or increased levels of synaptic excitation, and therefore suggested treatments aimed at increasing inhibition could further promote hypoactivity instead of normality. In this review, I highlight shared mechanisms across animal models for ASD, RTT, and AS with reduced synaptic excitation that nevertheless promote hyperexcitability in cortical circuits.
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Affiliation(s)
- Michelle W. Antoine
- Section on Neural Circuits, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, United States
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7
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Mortazavi A, Fayed I, Bachani M, Dowdy T, Jahanipour J, Khan A, Owotade J, Walbridge S, Inati SK, Steiner J, Wu J, Gilbert M, Yang CZ, Larion M, Maric D, Ksendzovsky A, Zaghloul KA. IDH-mutated gliomas promote epileptogenesis through d-2-hydroxyglutarate-dependent mTOR hyperactivation. Neuro Oncol 2022; 24:1423-1435. [PMID: 34994387 PMCID: PMC9435503 DOI: 10.1093/neuonc/noac003] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Uncontrolled seizures in patients with gliomas have a significant impact on quality of life and morbidity, yet the mechanisms through which these tumors cause seizures remain unknown. Here, we hypothesize that the active metabolite d-2-hydroxyglutarate (d-2-HG) produced by the IDH-mutant enzyme leads to metabolic disruptions in surrounding cortical neurons that consequently promote seizures. METHODS We use a complementary study of in vitro neuron-glial cultures and electrographically sorted human cortical tissue from patients with IDH-mutant gliomas to test this hypothesis. We utilize micro-electrode arrays for in vitro electrophysiological studies in combination with pharmacological manipulations and biochemical studies to better elucidate the impact of d-2-HG on cortical metabolism and neuronal spiking activity. RESULTS We demonstrate that d-2-HG leads to increased neuronal spiking activity and promotes a distinct metabolic profile in surrounding neurons, evidenced by distinct metabolomic shifts and increased LDHA expression, as well as upregulation of mTOR signaling. The increases in neuronal activity are induced by mTOR activation and reversed with mTOR inhibition. CONCLUSION Together, our data suggest that metabolic disruptions in the surrounding cortex due to d-2-HG may be a driving event for epileptogenesis in patients with IDH-mutant gliomas.
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Affiliation(s)
- Armin Mortazavi
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, Maryland, USA
| | - Islam Fayed
- Department of Neurosurgery, Georgetown University, Washington, District of Columbia, USA
| | - Muzna Bachani
- NeuroTherapeutics Development Unit, NINDS, National Institutes of Health, Bethesda, Maryland, USA
| | - Tyrone Dowdy
- NeuroOncology Branch, NCI, National Institutes of Health, Bethesda, Maryland, USA
| | - Jahandar Jahanipour
- Flow and Cytometry Core, NINDS, National Institutes of Health, Bethesda, Maryland, USA
| | - Anas Khan
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, Maryland, USA
| | - Jemima Owotade
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, Maryland, USA
| | - Stuart Walbridge
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, Maryland, USA
| | - Sara K Inati
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, Maryland, USA
| | - Joseph Steiner
- NeuroTherapeutics Development Unit, NINDS, National Institutes of Health, Bethesda, Maryland, USA
| | - Jing Wu
- NeuroOncology Branch, NCI, National Institutes of Health, Bethesda, Maryland, USA
| | - Mark Gilbert
- NeuroOncology Branch, NCI, National Institutes of Health, Bethesda, Maryland, USA
| | - Chun Zhang Yang
- NeuroOncology Branch, NCI, National Institutes of Health, Bethesda, Maryland, USA
| | - Mioara Larion
- NeuroOncology Branch, NCI, National Institutes of Health, Bethesda, Maryland, USA
| | - Dragan Maric
- Flow and Cytometry Core, NINDS, National Institutes of Health, Bethesda, Maryland, USA
| | | | - Kareem A Zaghloul
- Corresponding Author: Kareem A. Zaghloul, MD, PhD, Surgical Neurology Branch, NINDS, National Institutes of Health, Building 10, Room 3D20, 10 Center Drive Bethesda, MD 20892-1414, USA ()
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Liu J, Luo M, Lv S, Tao S, Wu Z, Yu L, Lin D, Huang L, Wu L, Liao X, Zi J, Lai X, Yuan Y, Zhang W, Yang L. Case Report: Reversible Hyperglycemia Following Rapamycin Treatment for Atypical Choroid Plexus Papilloma in an Infant. Front Endocrinol (Lausanne) 2022; 13:865913. [PMID: 35865311 PMCID: PMC9294177 DOI: 10.3389/fendo.2022.865913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 05/11/2022] [Indexed: 12/16/2022] Open
Abstract
In this study, atypical choroid plexus papilloma was treated with high-dose rapamycin for 17 days preoperatively in an infant. Rapamycin significantly reduced the blood supply to the tumor while reducing the tumor volume, and most of the tumor was resected successfully. However, the infant developed hyperglycemia related to the rapamycin dose, which was effectively controlled by adjusting the dose and applying insulin.
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Affiliation(s)
- Jiale Liu
- Department of Pediatric Hematology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Minjie Luo
- Department of Pediatric Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Siyuan Lv
- Department of Pediatric Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Shaohua Tao
- Department of Pediatric Intensive Care Unit, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Zhu Wu
- Department of Pediatric Intensive Care Unit, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Lihua Yu
- Department of Pediatric Hematology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Danna Lin
- Department of Pediatric Hematology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Lulu Huang
- Department of Pediatric Hematology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Li Wu
- Department of Pediatric Hematology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Xu Liao
- Department of Pediatric Hematology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Juan Zi
- Department of Pediatric Hematology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Xiaorong Lai
- Department of Pediatric Hematology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Yuting Yuan
- Department of Pediatric Hematology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Wangming Zhang
- Department of Pediatric Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
- *Correspondence: Wangming Zhang, ; Lihua Yang,
| | - Lihua Yang
- Department of Pediatric Hematology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
- *Correspondence: Wangming Zhang, ; Lihua Yang,
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Koene LM, Niggl E, Wallaard I, Proietti-Onori M, Rotaru DC, Elgersma Y. Identifying the temporal electrophysiological and molecular changes that contribute to TSC-associated epileptogenesis. JCI Insight 2021; 6:e150120. [PMID: 34877936 PMCID: PMC8675202 DOI: 10.1172/jci.insight.150120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 10/27/2021] [Indexed: 11/17/2022] Open
Abstract
Tuberous sclerosis complex (TSC), caused by heterozygous mutations in TSC1 or TSC2, frequently results in intractable epilepsy. Here, we made use of an inducible Tsc1-knockout mouse model, allowing us to study electrophysiological and molecular changes of Tsc1-induced epileptogenesis over time. We recorded from pyramidal neurons in the hippocampus and somatosensory cortex (L2/L3) and combined this with an analysis of transcriptome changes during epileptogenesis. Deletion of Tsc1 resulted in hippocampus-specific changes in excitability and adaptation, which emerged before seizure onset and progressed over time. All phenotypes were rescued after early treatment with rapamycin, an mTOR inhibitor. Later in epileptogenesis, we observed a hippocampal increase of excitation-to-inhibition ratio. These cellular changes were accompanied by dramatic transcriptional changes, especially after seizure onset. Most of these changes were rescued upon rapamycin treatment. Of the genes encoding ion channels or belonging to the Gene Ontology term action potential, 27 were differentially expressed just before seizure onset, suggesting a potential driving role in epileptogenesis. Our data highlight the complex changes driving epileptogenesis in TSC, including the changed expression of multiple ion channels. Our study emphasizes inhibition of the TSC/mTOR signaling pathway as a promising therapeutic approach to target epilepsy in patients with TSC.
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Vasic V, Jones MSO, Haslinger D, Knaus LS, Schmeisser MJ, Novarino G, Chiocchetti AG. Translating the Role of mTOR- and RAS-Associated Signalopathies in Autism Spectrum Disorder: Models, Mechanisms and Treatment. Genes (Basel) 2021; 12:genes12111746. [PMID: 34828352 PMCID: PMC8624393 DOI: 10.3390/genes12111746] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/25/2021] [Accepted: 10/28/2021] [Indexed: 12/23/2022] Open
Abstract
Mutations affecting mTOR or RAS signaling underlie defined syndromes (the so-called mTORopathies and RASopathies) with high risk for Autism Spectrum Disorder (ASD). These syndromes show a broad variety of somatic phenotypes including cancers, skin abnormalities, heart disease and facial dysmorphisms. Less well studied are the neuropsychiatric symptoms such as ASD. Here, we assess the relevance of these signalopathies in ASD reviewing genetic, human cell model, rodent studies and clinical trials. We conclude that signalopathies have an increased liability for ASD and that, in particular, ASD individuals with dysmorphic features and intellectual disability (ID) have a higher chance for disruptive mutations in RAS- and mTOR-related genes. Studies on rodent and human cell models confirm aberrant neuronal development as the underlying pathology. Human studies further suggest that multiple hits are necessary to induce the respective phenotypes. Recent clinical trials do only report improvements for comorbid conditions such as epilepsy or cancer but not for behavioral aspects. Animal models show that treatment during early development can rescue behavioral phenotypes. Taken together, we suggest investigating the differential roles of mTOR and RAS signaling in both human and rodent models, and to test drug treatment both during and after neuronal development in the available model systems.
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Affiliation(s)
- Verica Vasic
- Institute for Microscopic Anatomy and Neurobiology, University Medical Center of the Johannes Gutenberg-University, 55131 Mainz, Germany; (V.V.); (M.J.S.)
| | - Mattson S. O. Jones
- Autism Therapy and Research Center of Excellence, Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Frankfurt, 60528 Frankfurt am Main, Germany; (M.S.O.J.); (D.H.)
- Center for Personalized Translational Epilepsy Research (CePTER), Goethe University Frankfurt, 60528 Frankfurt am Main, Germany
| | - Denise Haslinger
- Autism Therapy and Research Center of Excellence, Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Frankfurt, 60528 Frankfurt am Main, Germany; (M.S.O.J.); (D.H.)
- Institute of Science and Technology (IST) Austria, 3400 Klosterneuburg, Austria; (L.S.K.); (G.N.)
| | - Lisa S. Knaus
- Institute of Science and Technology (IST) Austria, 3400 Klosterneuburg, Austria; (L.S.K.); (G.N.)
| | - Michael J. Schmeisser
- Institute for Microscopic Anatomy and Neurobiology, University Medical Center of the Johannes Gutenberg-University, 55131 Mainz, Germany; (V.V.); (M.J.S.)
- Focus Program Translational Neurosciences (FTN), University Medical Center of the Johannes Gutenberg-University, 55131 Mainz, Germany
| | - Gaia Novarino
- Institute of Science and Technology (IST) Austria, 3400 Klosterneuburg, Austria; (L.S.K.); (G.N.)
| | - Andreas G. Chiocchetti
- Autism Therapy and Research Center of Excellence, Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Frankfurt, 60528 Frankfurt am Main, Germany; (M.S.O.J.); (D.H.)
- Center for Personalized Translational Epilepsy Research (CePTER), Goethe University Frankfurt, 60528 Frankfurt am Main, Germany
- Correspondence: ; Tel.: +49-69-6301-80658
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11
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Moloney PB, Cavalleri GL, Delanty N. Epilepsy in the mTORopathies: opportunities for precision medicine. Brain Commun 2021; 3:fcab222. [PMID: 34632383 PMCID: PMC8495134 DOI: 10.1093/braincomms/fcab222] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/23/2021] [Accepted: 08/30/2021] [Indexed: 01/16/2023] Open
Abstract
The mechanistic target of rapamycin signalling pathway serves as a ubiquitous regulator of cell metabolism, growth, proliferation and survival. The main cellular activity of the mechanistic target of rapamycin cascade funnels through mechanistic target of rapamycin complex 1, which is inhibited by rapamycin, a macrolide compound produced by the bacterium Streptomyces hygroscopicus. Pathogenic variants in genes encoding upstream regulators of mechanistic target of rapamycin complex 1 cause epilepsies and neurodevelopmental disorders. Tuberous sclerosis complex is a multisystem disorder caused by mutations in mechanistic target of rapamycin regulators TSC1 or TSC2, with prominent neurological manifestations including epilepsy, focal cortical dysplasia and neuropsychiatric disorders. Focal cortical dysplasia type II results from somatic brain mutations in mechanistic target of rapamycin pathway activators MTOR, AKT3, PIK3CA and RHEB and is a major cause of drug-resistant epilepsy. DEPDC5, NPRL2 and NPRL3 code for subunits of the GTPase-activating protein (GAP) activity towards Rags 1 complex (GATOR1), the principal amino acid-sensing regulator of mechanistic target of rapamycin complex 1. Germline pathogenic variants in GATOR1 genes cause non-lesional focal epilepsies and epilepsies associated with malformations of cortical development. Collectively, the mTORopathies are characterized by excessive mechanistic target of rapamycin pathway activation and drug-resistant epilepsy. In the first large-scale precision medicine trial in a genetically mediated epilepsy, everolimus (a synthetic analogue of rapamycin) was effective at reducing seizure frequency in people with tuberous sclerosis complex. Rapamycin reduced seizures in rodent models of DEPDC5-related epilepsy and focal cortical dysplasia type II. This review outlines a personalized medicine approach to the management of epilepsies in the mTORopathies. We advocate for early diagnostic sequencing of mechanistic target of rapamycin pathway genes in drug-resistant epilepsy, as identification of a pathogenic variant may point to an occult dysplasia in apparently non-lesional epilepsy or may uncover important prognostic information including, an increased risk of sudden unexpected death in epilepsy in the GATORopathies or favourable epilepsy surgery outcomes in focal cortical dysplasia type II due to somatic brain mutations. Lastly, we discuss the potential therapeutic application of mechanistic target of rapamycin inhibitors for drug-resistant seizures in GATOR1-related epilepsies and focal cortical dysplasia type II.
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Affiliation(s)
- Patrick B Moloney
- FutureNeuro, the Science Foundation Ireland Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons in Ireland, Dublin, D02 VN51, Ireland
| | - Gianpiero L Cavalleri
- FutureNeuro, the Science Foundation Ireland Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons in Ireland, Dublin, D02 VN51, Ireland
| | - Norman Delanty
- FutureNeuro, the Science Foundation Ireland Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons in Ireland, Dublin, D02 VN51, Ireland
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12
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Tuberous Sclerosis Complex (TSC) Inactivation Increases Neuronal Network Activity by Enhancing Ca 2+ Influx via L-Type Ca 2+ Channels. J Neurosci 2021; 41:8134-8149. [PMID: 34417327 DOI: 10.1523/jneurosci.1930-20.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/09/2021] [Accepted: 08/11/2021] [Indexed: 12/19/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a multisystem developmental disorder characterized by hamartomas in various organs, such as the brain, lungs, and kidneys. Epilepsy, along with autism and intellectual disability, is one of the neurologic impairments associated with TSC that has an intimate relationship with developmental outcomes and quality of life. Sustained activation of the mammalian target of rapamycin (mTOR) via TSC1 or TSC2 mutations is known to be involved in the onset of epilepsy in TSC. However, the mechanism by which mTOR causes seizures remains unknown. In this study, we showed that, human induced pluripotent stem cell-derived TSC2-deficient (TSC2 -/-) neurons exhibited elevated neuronal activity with highly synchronized Ca2+ spikes. Notably, TSC2 -/- neurons presented enhanced Ca2+ influx via L-type Ca2+ channels (LTCCs), which contributed to the abnormal neurite extension and sustained activation of cAMP response element binding protein (CREB), a critical mediator of synaptic plasticity. Expression of Cav1.3, a subtype of LTCCs, was increased in TSC2 -/- neurons, but long-term rapamycin treatment suppressed this increase and reversed the altered neuronal activity and neurite extensions. Thus, we identified Cav1.3 LTCC as a critical downstream component of TSC-mTOR signaling that would trigger enhanced neuronal network activity of TSC2 -/- neurons. We suggest that LTCCs could be potential novel targets for the treatment of epilepsy in TSC.SIGNIFICANCE STATEMENT There is a close relationship between elevated mammalian target of rapamycin (mTOR) activity and epilepsy in tuberous sclerosis complex (TSC). However, the underlying mechanism by which mTOR causes epilepsy remains unknown. In this study, using human TSC2 -/- neurons, we identified elevated Ca2+ influx via L-type Ca2+ channels as a critical downstream component of TSC-mTOR signaling and a potential cause of both elevated neuronal activity and neurite extension in TSC2 -/- neurons. Our findings demonstrate a previously unrecognized connection between sustained mTOR activation and elevated Ca2+ signaling via L-type Ca2+ channels in human TSC neurons, which could cause epilepsy in TSC.
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13
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Selected Molecular Targets for Antiepileptogenesis. Int J Mol Sci 2021; 22:ijms22189737. [PMID: 34575901 PMCID: PMC8466306 DOI: 10.3390/ijms22189737] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/02/2021] [Accepted: 09/02/2021] [Indexed: 02/07/2023] Open
Abstract
The term epileptogenesis defines the usually durable process of converting normal brain into an epileptic one. The resistance of a significant proportion of patients with epilepsy to the available pharmacotherapy prompted the concept of a causative treatment option consisting in stopping or modifying the progress of epileptogenesis. Most antiepileptic drugs possess only a weak or no antiepileptogenic potential at all, but a few of them appear promising in this regard; these include, for example, eslicarbazepine (a sodium and T-type channel blocker), lamotrigine (a sodium channel blocker and glutamate antagonist) or levetiracetam (a ligand of synaptic vehicle protein SV2A). Among the approved non-antiepileptic drugs, antiepileptogenic potential seems to reside in losartan (a blocker of angiotensin II type 1 receptors), biperiden (an antiparkinsonian drug), nonsteroidal anti-inflammatory drugs, antioxidative drugs and minocycline (a second-generation tetracycline with anti-inflammatory and antioxidant properties). Among other possible antiepileptogenic compounds, antisense nucleotides have been considered, among these an antagomir targeting microRNA-134. The drugs and agents mentioned above have been evaluated in post-status epilepticus models of epileptogenesis, so their preventive efficacy must be verified. Limited clinical data indicate that biperiden in patients with brain injuries is well-tolerated and seems to reduce the incidence of post-traumatic epilepsy. Exceptionally, in this regard, our own original data presented here point to c-Fos as an early seizure duration, but not seizure intensity-related, marker of early epileptogenesis. Further research of reliable markers of early epileptogenesis is definitely needed to improve the process of designing adequate antiepileptogenic therapies.
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14
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A Warburg-like metabolic program coordinates Wnt, AMPK, and mTOR signaling pathways in epileptogenesis. PLoS One 2021; 16:e0252282. [PMID: 34358226 PMCID: PMC8345866 DOI: 10.1371/journal.pone.0252282] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 05/12/2021] [Indexed: 02/06/2023] Open
Abstract
Epilepsy is a complex neurological condition characterized by repeated spontaneous seizures and can be induced by initiating seizures known as status epilepticus (SE). Elaborating the critical molecular mechanisms following SE are central to understanding the establishment of chronic seizures. Here, we identify a transient program of molecular and metabolic signaling in the early epileptogenic period, centered on day five following SE in the pre-clinical kainate or pilocarpine models of temporal lobe epilepsy. Our work now elaborates a new molecular mechanism centered around Wnt signaling and a growing network comprised of metabolic reprogramming and mTOR activation. Biochemical, metabolomic, confocal microscopy and mouse genetics experiments all demonstrate coordinated activation of Wnt signaling, predominantly in neurons, and the ensuing induction of an overall aerobic glycolysis (Warburg-like phenomenon) and an altered TCA cycle in early epileptogenesis. A centerpiece of the mechanism is the regulation of pyruvate dehydrogenase (PDH) through its kinase and Wnt target genes PDK4. Intriguingly, PDH is a central gene in certain genetic epilepsies, underscoring the relevance of our elaborated mechanisms. While sharing some features with cancers, the Warburg-like metabolism in early epileptogenesis is uniquely split between neurons and astrocytes to achieve an overall novel metabolic reprogramming. This split Warburg metabolic reprogramming triggers an inhibition of AMPK and subsequent activation of mTOR, which is a signature event of epileptogenesis. Interrogation of the mechanism with the metabolic inhibitor 2-deoxyglucose surprisingly demonstrated that Wnt signaling and the resulting metabolic reprogramming lies upstream of mTOR activation in epileptogenesis. To augment the pre-clinical pilocarpine and kainate models, aspects of the proposed mechanisms were also investigated and correlated in a genetic model of constitutive Wnt signaling (deletion of the transcriptional repressor and Wnt pathway inhibitor HBP1). The results from the HBP1-/- mice provide a genetic evidence that Wnt signaling may set the threshold of acquired seizure susceptibility with a similar molecular framework. Using biochemistry and genetics, this paper outlines a new molecular framework of early epileptogenesis and advances a potential molecular platform for refining therapeutic strategies in attenuating recurrent seizures.
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15
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Wang T, Zhou M, Zhang Q, Zhang C, Peng G. ubtor Mutation Causes Motor Hyperactivity by Activating mTOR Signaling in Zebrafish. Neurosci Bull 2021; 37:1658-1670. [PMID: 34309811 PMCID: PMC8643380 DOI: 10.1007/s12264-021-00755-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 04/08/2021] [Indexed: 01/20/2023] Open
Abstract
Mechanistic target of rapamycin (mTOR) signaling governs important physiological and pathological processes key to cellular life. Loss of mTOR negative regulators and subsequent over-activation of mTOR signaling are major causes underlying epileptic encephalopathy. Our previous studies showed that UBTOR/KIAA1024/MINAR1 acts as a negative regulator of mTOR signaling, but whether UBTOR plays a role in neurological diseases remains largely unknown. We therefore examined a zebrafish model and found that ubtor disruption caused increased spontaneous embryonic movement and neuronal activity in spinal interneurons, as well as the expected hyperactivation of mTOR signaling in early zebrafish embryos. In addition, mutant ubtor larvae showed increased sensitivity to the convulsant pentylenetetrazol, and both the motor activity and the neuronal activity were up-regulated. These phenotypic abnormalities in zebrafish embryos and larvae were rescued by treatment with the mTORC1 inhibitor rapamycin. Taken together, our findings show that ubtor regulates motor hyperactivity and epilepsy-like behaviors by elevating neuronal activity and activating mTOR signaling.
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Affiliation(s)
- Tiantian Wang
- State Key Laboratory of Medical Neurobiology, Ministry of Education Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Mingshan Zhou
- State Key Laboratory of Medical Neurobiology, Ministry of Education Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Quan Zhang
- State Key Laboratory of Medical Neurobiology, Ministry of Education Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Cuizhen Zhang
- State Key Laboratory of Medical Neurobiology, Ministry of Education Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Gang Peng
- State Key Laboratory of Medical Neurobiology, Ministry of Education Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
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16
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Proietti Onori M, Koene LMC, Schäfer CB, Nellist M, de Brito van Velze M, Gao Z, Elgersma Y, van Woerden GM. RHEB/mTOR hyperactivity causes cortical malformations and epileptic seizures through increased axonal connectivity. PLoS Biol 2021; 19:e3001279. [PMID: 34038402 PMCID: PMC8186814 DOI: 10.1371/journal.pbio.3001279] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 06/08/2021] [Accepted: 05/10/2021] [Indexed: 01/03/2023] Open
Abstract
Hyperactivation of the mammalian target of rapamycin (mTOR) pathway can cause malformation of cortical development (MCD) with associated epilepsy and intellectual disability (ID) through a yet unknown mechanism. Here, we made use of the recently identified dominant-active mutation in Ras Homolog Enriched in Brain 1 (RHEB), RHEBp.P37L, to gain insight in the mechanism underlying the epilepsy caused by hyperactivation of the mTOR pathway. Focal expression of RHEBp.P37L in mouse somatosensory cortex (SScx) results in an MCD-like phenotype, with increased mTOR signaling, ectopic localization of neurons, and reliable generalized seizures. We show that in this model, the mTOR-dependent seizures are caused by enhanced axonal connectivity, causing hyperexcitability of distally connected neurons. Indeed, blocking axonal vesicle release from the RHEBp.P37L neurons alone completely stopped the seizures and normalized the hyperexcitability of the distally connected neurons. These results provide new evidence of the extent of anatomical and physiological abnormalities caused by mTOR hyperactivity, beyond local malformations, which can lead to generalized epilepsy. Hyperactivation of the mTOR pathway can cause cortical malformations and epilepsy. This study reveals that these effects can be uncoupled and that mTOR hyperactivity in a limited set of neurons induces hyperexcitability in non-targeted, healthy neurons, suggesting that it is actually these changes that may underlie mTOR-driven epileptogenesis.
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Affiliation(s)
- Martina Proietti Onori
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands
- The ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Linda M. C. Koene
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands
- The ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Carmen B. Schäfer
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Mark Nellist
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, Zuid Holland, the Netherlands
| | | | - Zhenyu Gao
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Ype Elgersma
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands
- The ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus Medical Center, Rotterdam, the Netherlands
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, Zuid Holland, the Netherlands
- * E-mail: (YE); (GMvW)
| | - Geeske M. van Woerden
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands
- The ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus Medical Center, Rotterdam, the Netherlands
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, Zuid Holland, the Netherlands
- * E-mail: (YE); (GMvW)
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17
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Novel brain permeant mTORC1/2 inhibitors are as efficacious as rapamycin or everolimus in mouse models of acquired partial epilepsy and tuberous sclerosis complex. Neuropharmacology 2020; 180:108297. [PMID: 32890589 DOI: 10.1016/j.neuropharm.2020.108297] [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: 06/17/2020] [Revised: 08/27/2020] [Accepted: 09/01/2020] [Indexed: 12/24/2022]
Abstract
Mechanistic target of rapamycin (mTOR) regulates cell proliferation, growth and survival, and is activated in cancer and neurological disorders, including epilepsy. The rapamycin derivative ("rapalog") everolimus, which allosterically inhibits the mTOR pathway, is approved for the treatment of partial epilepsy with spontaneous recurrent seizures (SRS) in individuals with tuberous sclerosis complex (TSC). In contrast to the efficacy in TSC, the efficacy of rapalogs on SRS in other types of epilepsy is equivocal. Furthermore, rapalogs only poorly penetrate into the brain and are associated with peripheral adverse effects, which may compromise their therapeutic efficacy. Here we compare the antiseizure efficacy of two novel, brain-permeable ATP-competitive and selective mTORC1/2 inhibitors, PQR620 and PQR626, and the selective dual pan-PI3K/mTORC1/2 inhibitor PQR530 in two mouse models of chronic epilepsy with SRS, the intrahippocampal kainate (IHK) mouse model of acquired temporal lobe epilepsy and Tsc1GFAP CKO mice, a well-characterized mouse model of epilepsy in TSC. During prolonged treatment of IHK mice with rapamycin, everolimus, PQR620, PQR626, or PQR530; only PQR620 exerted a transient antiseizure effect on SRS, at well tolerated doses whereas the other compounds were ineffective. In contrast, all of the examined compounds markedly suppressed SRS in Tsc1GFAP CKO mice during chronic treatment at well tolerated doses. Thus, against our expectation, no clear differences in antiseizure efficacy were found across the three classes of mTOR inhibitors examined in mouse models of genetic and acquired epilepsies. The main advantage of the novel 1,3,5-triazine derivatives is their excellent tolerability compared to rapalogs, which would favor their development as new therapies for TORopathies such as TSC.
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18
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Auvin S, Avbersek A, Bast T, Chiron C, Guerrini R, Kaminski RM, Lagae L, Muglia P, Cross JH. Drug Development for Rare Paediatric Epilepsies: Current State and Future Directions. Drugs 2020; 79:1917-1935. [PMID: 31734883 DOI: 10.1007/s40265-019-01223-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Rare diseases provide a challenge in the evaluation of new therapies. However, orphan drug development is of increasing interest because of the legislation enabling facilitated support by regulatory agencies through scientific advice, and the protection of the molecules with orphan designation. In the landscape of the rare epilepsies, very few syndromes, namely Dravet syndrome, Lennox-Gastaut syndrome and West syndrome, have been subject to orphan drug development. Despite orphan designations for rare epilepsies having dramatically increased in the past 10 years, the number of approved drugs remains limited and restricted to a handful of epilepsy syndromes. In this paper, we describe the current state of orphan drug development for rare epilepsies. We identified a large number of compounds currently under investigation, but mostly in the same rare epilepsy syndromes as in the past. A rationale for further development in rare epilepsies could be based on the match between the drug mechanisms of action and the knowledge of the causative gene mutation or by evidence from animal models. In case of the absence of strong pathophysiological hypotheses, exploratory/basket clinical studies could be helpful to identify a subpopulation that may benefit from the new drug. We provide some suggestions for future improvements in orphan drug development such as promoting paediatric drug investigations, better evaluation of the incidence and the prevalence, together with the natural history data, and the development of new primary outcomes.
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Affiliation(s)
- Stéphane Auvin
- PROTECT, INSERM U1141, Université de Paris, Paris, France. .,Service de Neurologie Pédiatrique, AP-HP, Hôpital Universitaire Robert-Debré, 48, Boulevard Sérurier, 75935, Paris Cedex 19, France.
| | | | - Thomas Bast
- The Kork Epilepsy Center, Kehl-Kork, Germany.,Medical Faculty of the University of Freiburg, Freiburg, Germany
| | - Catherine Chiron
- PROTECT, INSERM U1141, Université de Paris, Paris, France.,Service de Neurologie Pédiatrique, AP-HP, Hôpital Necker-Enfanst Malades, Paris, France
| | - Renzo Guerrini
- Neuroscience Department, Children's Hospital Anna Meyer-University of Florence, Florence, Italy
| | - Rafal M Kaminski
- UCB Pharma, Braine-l'Alleud, Belgium.,Roche Pharma Research and Early Development (pRED), Roche Innovation Center, Basel, Switzerland
| | - Lieven Lagae
- Department Development and Regeneration, Section Paediatric Neurology, University Hospitals, University of Leuven, Leuven, Belgium
| | | | - J Helen Cross
- UCL NIHR BRC Great Ormond Street Institute of Child Health, London, UK
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19
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Liu GY, Sabatini DM. mTOR at the nexus of nutrition, growth, ageing and disease. Nat Rev Mol Cell Biol 2020; 21:183-203. [PMID: 31937935 PMCID: PMC7102936 DOI: 10.1038/s41580-019-0199-y] [Citation(s) in RCA: 1390] [Impact Index Per Article: 347.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/26/2019] [Indexed: 12/21/2022]
Abstract
The mTOR pathway integrates a diverse set of environmental cues, such as growth factor signals and nutritional status, to direct eukaryotic cell growth. Over the past two and a half decades, mapping of the mTOR signalling landscape has revealed that mTOR controls biomass accumulation and metabolism by modulating key cellular processes, including protein synthesis and autophagy. Given the pathway's central role in maintaining cellular and physiological homeostasis, dysregulation of mTOR signalling has been implicated in metabolic disorders, neurodegeneration, cancer and ageing. In this Review, we highlight recent advances in our understanding of the complex regulation of the mTOR pathway and discuss its function in the context of physiology, human disease and pharmacological intervention.
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Affiliation(s)
- Grace Y Liu
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA
- Broad Institute, Cambridge, MA, USA
- The David H. Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA, USA
| | - David M Sabatini
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA.
- Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Broad Institute, Cambridge, MA, USA.
- The David H. Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA, USA.
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20
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Klein P, Friedman A, Hameed MQ, Kaminski RM, Bar-Klein G, Klitgaard H, Koepp M, Jozwiak S, Prince DA, Rotenberg A, Twyman R, Vezzani A, Wong M, Löscher W. Repurposed molecules for antiepileptogenesis: Missing an opportunity to prevent epilepsy? Epilepsia 2020; 61:359-386. [PMID: 32196665 PMCID: PMC8317585 DOI: 10.1111/epi.16450] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 01/26/2020] [Accepted: 01/27/2020] [Indexed: 12/11/2022]
Abstract
Prevention of epilepsy is a great unmet need. Acute central nervous system (CNS) insults such as traumatic brain injury (TBI), cerebrovascular accidents (CVA), and CNS infections account for 15%-20% of all epilepsy. Following TBI and CVA, there is a latency of days to years before epilepsy develops. This allows treatment to prevent or modify postinjury epilepsy. No such treatment exists. In animal models of acquired epilepsy, a number of medications in clinical use for diverse indications have been shown to have antiepileptogenic or disease-modifying effects, including medications with excellent side effect profiles. These include atorvastatin, ceftriaxone, losartan, isoflurane, N-acetylcysteine, and the antiseizure medications levetiracetam, brivaracetam, topiramate, gabapentin, pregabalin, vigabatrin, and eslicarbazepine acetate. In addition, there are preclinical antiepileptogenic data for anakinra, rapamycin, fingolimod, and erythropoietin, although these medications have potential for more serious side effects. However, except for vigabatrin, there have been almost no translation studies to prevent or modify epilepsy using these potentially "repurposable" medications. We may be missing an opportunity to develop preventive treatment for epilepsy by not evaluating these medications clinically. One reason for the lack of translation studies is that the preclinical data for most of these medications are disparate in terms of types of injury, models within different injury type, dosing, injury-treatment initiation latencies, treatment duration, and epilepsy outcome evaluation mode and duration. This makes it difficult to compare the relative strength of antiepileptogenic evidence across the molecules, and difficult to determine which drug(s) would be the best to evaluate clinically. Furthermore, most preclinical antiepileptogenic studies lack information needed for translation, such as dose-blood level relationship, brain target engagement, and dose-response, and many use treatment parameters that cannot be applied clinically, for example, treatment initiation before or at the time of injury and dosing higher than tolerated human equivalent dosing. Here, we review animal and human antiepileptogenic evidence for these medications. We highlight the gaps in our knowledge for each molecule that need to be filled in order to consider clinical translation, and we suggest a platform of preclinical antiepileptogenesis evaluation of potentially repurposable molecules or their combinations going forward.
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Affiliation(s)
- Pavel Klein
- Mid-Atlantic Epilepsy and Sleep Center, Bethesda, Maryland
| | - Alon Friedman
- Departments of Physiology and Cell Biology, and Brain and Cognitive Science, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Departments of Medical Neuroscience and Brain Repair Center, Dalhousie University, Halifax, Canada
| | - Mustafa Q. Hameed
- Neuromodulation Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Rafal M. Kaminski
- Neurosymptomatic Domains Section, Roche Pharma Research & Early Development, Roche Innovation Center, Basel, Switzerland
| | - Guy Bar-Klein
- McKusick-Nathans Institute of Genetic Medicine, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Henrik Klitgaard
- Neurosciences Therapeutic Area, UCB Pharma, Braine-l’Alleud, Belgium
| | - Mathias Koepp
- Department of Clinical and Experimental Epilepsy, University College London Institute of Neurology, London, UK
| | - Sergiusz Jozwiak
- Department of Pediatric Neurology, Warsaw Medical University, Warsaw, Poland
| | - David A. Prince
- Neurology and the Neurological Sciences, Stanford University School of Medicine, Stanford, California
| | - Alexander Rotenberg
- Neuromodulation Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | | | - Annamaria Vezzani
- Department of Neuroscience, Mario Negri Institute for Pharmacological Research, Scientific Institute for Research and Health Care, Milan, Italy
| | - Michael Wong
- Department of Neurology, Washington University School of Medicine, St Louis, Missouri
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
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21
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Crino PB. Mechanistic target of rapamycin (mTOR) signaling in status epilepticus. Epilepsy Behav 2019; 101:106550. [PMID: 31732331 DOI: 10.1016/j.yebeh.2019.106550] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 09/06/2019] [Accepted: 09/07/2019] [Indexed: 10/25/2022]
Abstract
The mechanistic target of rapamycin (mTOR) pathway plays a critical role in brain development, neuronal shape and size, and synaptic plasticity, as well as learning and memory. Mutations in mTOR pathway genes (MPG) cause malformations of cortical development (MCDs) that are highly associated with often intractable epilepsy, thus highlighting an association between the mTOR pathway and establishment of the epileptic network. A growing body of preclinical evidence in in vitro and rodent model systems suggests that mTOR signaling may be altered in status epilepticus (SE) and that modulation of mTOR activation with mTOR inhibitors such as rapamycin (sirolimus) could provide new therapeutic avenues for treatment of both refractory epilepsy and SE. Rapamycin may have ubiquitous effects on all neuronal subtypes as well as astrocytes and seems to prevent the development of seizures following experimentally induced SE. To date, there have been no human studies focused on mTOR signaling in SE, but clearly, preclinical data support investigation into this pivotal cell signaling pathway. Thus, modulation of the mTOR pathway may provide a new strategy for treatment of SE and could have implications for the prevention of epilepsy in patients with SE. This article is part of the Special Issue "Proceedings of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures".
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Affiliation(s)
- Peter B Crino
- Department of Neurology, University of Maryland School of Medicine, 110 S. Paca St., Baltimore, MD 21201, United States of America.
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22
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Gericke B, Brandt C, Theilmann W, Welzel L, Schidlitzki A, Twele F, Kaczmarek E, Anjum M, Hillmann P, Löscher W. Selective inhibition of mTORC1/2 or PI3K/mTORC1/2 signaling does not prevent or modify epilepsy in the intrahippocampal kainate mouse model. Neuropharmacology 2019; 162:107817. [PMID: 31654704 DOI: 10.1016/j.neuropharm.2019.107817] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/26/2019] [Accepted: 10/18/2019] [Indexed: 12/23/2022]
Abstract
Dysregulation of the PI3K/Akt/mTOR pathway has been implicated in several brain disorders, including epilepsy. Rapamycin and similar compounds inhibit mTOR. complex 1 and have been reported to decrease seizures, delay seizure development, or prevent epileptogenesis in different animal models of genetic or acquired epilepsies. However, data for acquired epilepsy are inconsistent, which, at least in part, may be due to the poor brain penetration and long brain persistence of rapamycin and the fact that it blocks only one of the two cellular mTOR complexes. Here we examined the antiepileptogenic or disease-modifying effects of two novel, brain-permeable and well tolerated 1,3,5-triazine derivatives, the ATP-competitive mTORC1/2 inhibitor PQR620 and the dual pan-PI3K/mTORC1/2 inhibitor PQR530 in the intrahippocampal kainate mouse model, in which spontaneous seizures develop after status epilepticus (SE). Following kainate injection, the two compounds were administered over 2 weeks at doses previously been shown to block mTORC1/2 or PI3K/mTORC1/2 in the mouse brain. When spontaneous seizures were recorded by continuous (24/7) video-EEG recording starting 6 weeks after termination of treatment, no effects on incidence or frequency of seizures were observed. Drug treatment suppressed the epilepsy-induced activation of the PI3K/Akt/mTOR pathway in the hippocampus, but granule cell dispersion in the dentate gyrus was not prevented. When epilepsy-associated behavioral alterations were determined 12-14 weeks after kainate, mice pretreated with PQR620 or PQR530 exhibited reduced anxiety-related behavior in the light-dark box, indicating a disease-modifying effect. Overall, the data indicate that mTORC1/C2 or PI3K/mTORC1/C2 inhibition may not be an antiepileptogenic strategy for SE-induced epilepsy.
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Affiliation(s)
- Birthe Gericke
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Claudia Brandt
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Wiebke Theilmann
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Lisa Welzel
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Alina Schidlitzki
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Friederike Twele
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Edith Kaczmarek
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Muneeb Anjum
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | | | - Wolfgang Löscher
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
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Biallelic Mutations in TSC2 Lead to Abnormalities Associated with Cortical Tubers in Human iPSC-Derived Neurons. J Neurosci 2019; 39:9294-9305. [PMID: 31591157 DOI: 10.1523/jneurosci.0642-19.2019] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 08/02/2019] [Accepted: 08/30/2019] [Indexed: 12/18/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a genetic disorder caused by mutations in TSC1 or TSC2 Patients frequently have epilepsy, autism spectrum disorder, and/or intellectual disability, as well as other systemic manifestations. In this study, we differentiated human induced pluripotent stem cells (iPSCs) from a female patient with TSC with one or two mutations in TSC2 into neurons using induced expression of NGN2 to examine neuronal dysregulation associated with the neurological symptoms in TSC. Using this method, neuronal differentiation was comparable between the three genotypes of iPSCs. We observed that TSC2 +/- neurons show mTOR complex 1 (mTORC1) hyperactivation and associated increased cell body size and process outgrowth, as well as exacerbation of the abnormalities by loss of the second allele of TSC2 in TSC2 -/- neurons. Interestingly, iPSC-derived neurons with either a single or biallelic mutation in TSC2 demonstrated hypersynchrony and downregulation of FMRP targets. However, only neurons with biallelic mutations of TSC2 demonstrated hyperactivity and transcriptional dysregulation observed in cortical tubers. These data demonstrate that loss of one allele of TSC2 is sufficient to cause some morphological and physiological changes in human neurons but that biallelic mutations in TSC2 are necessary to induce gene expression dysregulation present in cortical tubers. Finally, we found that treatment of iPSC-derived neurons with rapamycin reduced neuronal activity and partially reversed gene expression abnormalities, demonstrating that mTOR dysregulation contributes to both phenotypes. Therefore, biallelic mutations in TSC2 and associated molecular dysfunction, including mTOR hyperactivation, may play a role in the development of cortical tubers.SIGNIFICANCE STATEMENT In this study, we examined neurons derived from induced pluripotent stem cells with two, one, or no functional TSC2 (tuberous sclerosis complex 2) alleles and found that loss of one or both alleles of TSC2 results in mTORC1 hyperactivation and specific neuronal abnormalities. However, only biallelic mutations in TSC2 resulted in elevated neuronal activity and upregulation of cell adhesion genes that is also observed in cortical tubers. These data suggest that loss of heterozygosity of TSC1 or TSC2 may play an important role in the development of cortical tubers, and potentially epilepsy, in patients with TSC.
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Overwater IE, Rietman AB, van Eeghen AM, de Wit MCY. Everolimus for the treatment of refractory seizures associated with tuberous sclerosis complex (TSC): current perspectives. Ther Clin Risk Manag 2019; 15:951-955. [PMID: 31440057 PMCID: PMC6666377 DOI: 10.2147/tcrm.s145630] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 05/26/2019] [Indexed: 12/21/2022] Open
Abstract
Up to 90% of patients with tuberous sclerosis complex (TSC) have epilepsy, and in over half of patients seizure control cannot be achieved by regular antiepileptic drugs. The underlying problem is mTOR hyperactivation due to loss of function of the TSC proteins. Treatment with everolimus, an mTOR inhibitor, has been shown to be of great benefit to TSC patients, both in reducing tumor growth and as a treatment for intractable epilepsy. Up to 40% of TSC patients with intractable epilepsy show a clinically relevant seizure response to everolimus. It has not yet fully lived up to its promise as a disease-modifying drug, however, as half of TSC patients with intractable epilepsy do not show a clinically relevant seizure frequency reduction. There is no evidence yet of a positive effect on the cognitive and neuropsychiatric deficits in TSC patients. In preclinical studies, mTOR inhibition can rescue abnormal neuronal migration and synapse formation that is caused by mTOR hyperactivation. These studies show a critical time window that suggests that mTOR inhibition may be most beneficial in young children. The trials done so far have not studied treatment in children under 2 years of age, although case series suggest that the safety profile is similar to that in older children. Further studies into the optimal time window, dosing schedules and possibly combination with other drugs may further improve the benefit of everolimus for TSC patients.
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Affiliation(s)
- Iris E Overwater
- Department of Pediatric Neurology and ENCORE Expertise Center, Erasmus MC, Rotterdam, the Netherlands
| | - André B Rietman
- Department of Child and Adolescent Psychiatry/Psychology and ENCORE Expertise Center, Erasmus MC, Rotterdam, the Netherlands
| | - Agnies M van Eeghen
- Heeren Loo Care Group and ENCORE Expertise Center, Erasmus MC, Rotterdam, the Netherlands
| | - Marie Claire Y de Wit
- Department of Pediatric Neurology and ENCORE Expertise Center, Erasmus MC, Rotterdam, the Netherlands
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25
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Koene LMC, van Grondelle SE, Proietti Onori M, Wallaard I, Kooijman NHRM, van Oort A, Schreiber J, Elgersma Y. Effects of antiepileptic drugs in a new TSC/mTOR-dependent epilepsy mouse model. Ann Clin Transl Neurol 2019; 6:1273-1291. [PMID: 31353861 PMCID: PMC6649373 DOI: 10.1002/acn3.50829] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 06/05/2019] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE An epilepsy mouse model for Tuberous Sclerosis Complex (TSC) was developed and validated to investigate the mechanisms underlying epileptogenesis. Furthermore, the possible antiepileptogenic properties of commonly used antiepileptic drugs (AEDs) and new compounds were assessed. METHODS Tsc1 deletion was induced in CAMK2A-expressing neurons of adult mice. The antiepileptogenic properties of commonly used AEDs and inhibitors of the mTOR pathways were assessed by EEG recordings and by molecular read outs. RESULTS Mice developed epilepsy in a narrow time window (10 ± 2 days) upon Tsc1 gene deletion. Seizure frequency but not duration increased over time. Seizures were lethal within 18 days, were unpredictable, and did not correlate to seizure onset, length or frequency, reminiscent of sudden unexpected death in epilepsy (SUDEP). Tsc1 gene deletion resulted in a strong activation of the mTORC1 pathway, and both epileptogenesis and lethality could be entirely prevented by RHEB1 gene deletion or rapamycin treatment. However, other inhibitors of the mTOR pathway such as AZD8055 and PF4708671 were ineffective. Except for ketogenic diet, none of commonly used AEDs showed an effect on mTORC1 activity. Vigabatrin and ketogenic diet treatment were able to significantly delay seizure onset. In contrast, survival was shortened by lamotrigine. INTERPRETATION This novel Tsc1 mouse model is highly suitable to assess the efficacy of antiepileptic and -epileptogenic drugs to treat mTORC1-dependent epilepsy. Additionally, it allows us to study the mechanisms underlying mTORC1-mediated epileptogenesis and SUDEP. We found that early treatment with vigabatrin was not able to prevent epilepsy, but significantly delayed seizure onset.
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Affiliation(s)
- Linda M. C. Koene
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental DisordersErasmus MC University Medical CenterRotterdam3015 CNThe Netherlands
| | - Saskia E. van Grondelle
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental DisordersErasmus MC University Medical CenterRotterdam3015 CNThe Netherlands
| | - Martina Proietti Onori
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental DisordersErasmus MC University Medical CenterRotterdam3015 CNThe Netherlands
| | - Ilse Wallaard
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental DisordersErasmus MC University Medical CenterRotterdam3015 CNThe Netherlands
| | - Nathalie H. R. M. Kooijman
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental DisordersErasmus MC University Medical CenterRotterdam3015 CNThe Netherlands
| | - Annabel van Oort
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental DisordersErasmus MC University Medical CenterRotterdam3015 CNThe Netherlands
| | - Jadwiga Schreiber
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental DisordersErasmus MC University Medical CenterRotterdam3015 CNThe Netherlands
| | - Ype Elgersma
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental DisordersErasmus MC University Medical CenterRotterdam3015 CNThe Netherlands
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Löscher W. The holy grail of epilepsy prevention: Preclinical approaches to antiepileptogenic treatments. Neuropharmacology 2019; 167:107605. [PMID: 30980836 DOI: 10.1016/j.neuropharm.2019.04.011] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 04/03/2019] [Accepted: 04/09/2019] [Indexed: 02/06/2023]
Abstract
A variety of acute brain insults can induce epileptogenesis, a complex process that results in acquired epilepsy. Despite advances in understanding mechanisms of epileptogenesis, there is currently no approved treatment that prevents the development or progression of epilepsy in patients at risk. The current concept of epileptogenesis assumes a window of opportunity following acute brain insults that allows intervention with preventive treatment. Recent results suggest that injury-induced epileptogenesis can be a much more rapid process than previously thought, suggesting that the 'therapeutic window' may only be open for a brief period, as in stroke therapy. However, experimental data also suggest a second, possibly delayed process ("secondary epileptogenesis") that influences the progression and refractoriness of the epileptic state over time, allowing interfering with this process even after onset of epilepsy. In this review, both methodological issues in preclinical drug development and novel targets for antiepileptogenesis will be discussed. Several promising drugs that either prevent epilepsy (antiepileptogenesis) or slow epilepsy progression and alleviate cognitive or behavioral comorbidities of epilepsy (disease modification) have been described in recent years, using diverse animal models of acquired epilepsy. Promising agents include TrkB inhibitors, losartan, statins, isoflurane, anti-inflammatory and anti-oxidative drugs, the SV2A modulator levetiracetam, and epigenetic interventions. Research on translational target validity and on prognostic biomarkers that can be used to stratify patients (or experimental animals) at high risk of developing epilepsy will hopefully soon lead to proof-of-concept clinical trials with the most promising drugs, which will be essential to make prevention of epilepsy a reality. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
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27
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Brandt C, Hillmann P, Noack A, Römermann K, Öhler LA, Rageot D, Beaufils F, Melone A, Sele AM, Wymann MP, Fabbro D, Löscher W. The novel, catalytic mTORC1/2 inhibitor PQR620 and the PI3K/mTORC1/2 inhibitor PQR530 effectively cross the blood-brain barrier and increase seizure threshold in a mouse model of chronic epilepsy. Neuropharmacology 2018; 140:107-120. [PMID: 30081001 DOI: 10.1016/j.neuropharm.2018.08.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 07/09/2018] [Accepted: 08/02/2018] [Indexed: 12/13/2022]
Abstract
The mTOR signaling pathway has emerged as a possible therapeutic target for epilepsy. Clinical trials have shown that mTOR inhibitors such as everolimus reduce seizures in tuberous sclerosis complex patients with intractable epilepsy. Furthermore, accumulating preclinical data suggest that mTOR inhibitors may have anti-seizure or anti-epileptogenic actions in other types of epilepsy. However, the chronic use of rapalogs such as everolimus is limited by poor tolerability, particularly by immunosuppression, poor brain penetration and induction of feedback loops which might contribute to their limited therapeutic efficacy. Here we describe two novel, brain-permeable and well tolerated small molecule 1,3,5-triazine derivatives, the catalytic mTORC1/C2 inhibitor PQR620 and the dual pan-PI3K/mTOR inhibitor PQR530. These derivatives were compared with the mTORC1 inhibitors rapamycin and everolimus as well as the anti-seizure drugs phenobarbital and levetiracetam. The anti-seizure potential of these compounds was determined by evaluating the electroconvulsive seizure threshold in normal and epileptic mice. Rapamycin and everolimus only poorly penetrated into the brain (brain:plasma ratio 0.0057 for rapamycin and 0.016 for everolimus). In contrast, the novel compounds rapidly entered the brain, reaching brain:plasma ratios of ∼1.6. Furthermore, they significantly decreased phosphorylation of S6 ribosomal protein in the hippocampus of normal and epileptic mice, demonstrating effective mTOR inhibition. PQR620 and PQR530 significantly increased seizure threshold at tolerable doses. The effect of PQR620 was more marked in epileptic vs. nonepileptic mice, matching the efficacy of levetiracetam. Overall, the novel compounds described here have the potential to overcome the disadvantages of rapalogs for treatment of epilepsy and mTORopathies directly connected to mutations in the mTOR signaling cascade.
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Affiliation(s)
- Claudia Brandt
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | | | - Andreas Noack
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Kerstin Römermann
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Leon A Öhler
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Denise Rageot
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | | | - Anna Melone
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Alexander M Sele
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | | | | | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
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28
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mTOR Signaling and Neural Stem Cells: The Tuberous Sclerosis Complex Model. Int J Mol Sci 2018; 19:ijms19051474. [PMID: 29772672 PMCID: PMC5983755 DOI: 10.3390/ijms19051474] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 05/04/2018] [Accepted: 05/11/2018] [Indexed: 12/24/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR), a serine-threonine kinase, plays a pivotal role in regulating cell growth and proliferation. Notably, a great deal of evidence indicates that mTOR signaling is also crucial in controlling proliferation and differentiation of several stem cell compartments. Consequently, dysregulation of the mTOR pathway is often associated with a variety of disease, such as cancer and metabolic and genetic disorders. For instance, hyperactivation of mTORC1 in neural stem cells (NSCs) is associated with the insurgence of neurological manifestation characterizing tuberous sclerosis complex (TSC). In this review, we survey the recent contributions of TSC physiopathology studies to understand the role of mTOR signaling in both neurogenesis and tumorigenesis and discuss how these new insights can contribute to developing new therapeutic strategies for neurological diseases and cancer.
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29
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Curatolo P, Moavero R, van Scheppingen J, Aronica E. mTOR dysregulation and tuberous sclerosis-related epilepsy. Expert Rev Neurother 2018; 18:185-201. [DOI: 10.1080/14737175.2018.1428562] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Paolo Curatolo
- Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University Hospital, Rome, Italy
| | - Romina Moavero
- Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University Hospital, Rome, Italy
- Child Neurology Unit, Neuroscience and Neurorehabilitation Department, “Bambino Gesù” Children’s Hospital, IRCCS, Rome, Italy
| | - Jackelien van Scheppingen
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), The Netherlands
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30
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mTOR-related neuropathology in mutant tsc2 zebrafish: Phenotypic, transcriptomic and pharmacological analysis. Neurobiol Dis 2017; 108:225-237. [DOI: 10.1016/j.nbd.2017.09.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 08/03/2017] [Accepted: 09/05/2017] [Indexed: 12/15/2022] Open
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31
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Reijnders MRF, Kousi M, van Woerden GM, Klein M, Bralten J, Mancini GMS, van Essen T, Proietti-Onori M, Smeets EEJ, van Gastel M, Stegmann APA, Stevens SJC, Lelieveld SH, Gilissen C, Pfundt R, Tan PL, Kleefstra T, Franke B, Elgersma Y, Katsanis N, Brunner HG. Variation in a range of mTOR-related genes associates with intracranial volume and intellectual disability. Nat Commun 2017; 8:1052. [PMID: 29051493 PMCID: PMC5648772 DOI: 10.1038/s41467-017-00933-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 08/08/2017] [Indexed: 11/09/2022] Open
Abstract
De novo mutations in specific mTOR pathway genes cause brain overgrowth in the context of intellectual disability (ID). By analyzing 101 mMTOR-related genes in a large ID patient cohort and two independent population cohorts, we show that these genes modulate brain growth in health and disease. We report the mTOR activator gene RHEB as an ID gene that is associated with megalencephaly when mutated. Functional testing of mutant RHEB in vertebrate animal models indicates pathway hyperactivation with a concomitant increase in cell and head size, aberrant neuronal migration, and induction of seizures, concordant with the human phenotype. This study reveals that tight control of brain volume is exerted through a large community of mTOR-related genes. Human brain volume can be altered, by either rare disruptive events causing hyperactivation of the pathway, or through the collective effects of common alleles.
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Affiliation(s)
- M R F Reijnders
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, 6500 GA, The Netherlands
| | - M Kousi
- Center for Human Disease Modeling, Duke University, Durham, NC, 27701, USA
| | - G M van Woerden
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus University Medical Center, 3015 CN, Rotterdam, The Netherlands
| | - M Klein
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, 6500 GA, The Netherlands
| | - J Bralten
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, 6500 GA, The Netherlands
| | - G M S Mancini
- Department of Clinical Genetics, Erasmus MC, Sophia Children's Hospital, 3000 CA, Rotterdam, The Netherlands
| | - T van Essen
- Department of Genetics, University of Groningen, University Medical Center of Groningen, 9700 RB, Groningen, The Netherlands
| | - M Proietti-Onori
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus University Medical Center, 3015 CN, Rotterdam, The Netherlands
| | - E E J Smeets
- Department of Clinical Genetics and School for Oncology & Developmental Biology (GROW), Maastricht University Medical Center, 6202 AZ, Maastricht, The Netherlands
| | - M van Gastel
- Department of Medical Care, SWZ zorg, 5691 AG, Son, The Netherlands
| | - A P A Stegmann
- Department of Clinical Genetics and School for Oncology & Developmental Biology (GROW), Maastricht University Medical Center, 6202 AZ, Maastricht, The Netherlands
| | - S J C Stevens
- Department of Clinical Genetics and School for Oncology & Developmental Biology (GROW), Maastricht University Medical Center, 6202 AZ, Maastricht, The Netherlands
| | - S H Lelieveld
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500 GA, Nijmegen, The Netherlands
| | - C Gilissen
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, 6500 GA, The Netherlands
| | - R Pfundt
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, 6500 GA, The Netherlands
| | - P L Tan
- Center for Human Disease Modeling, Duke University, Durham, NC, 27701, USA
| | - T Kleefstra
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, 6500 GA, The Netherlands
| | - B Franke
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, 6500 GA, The Netherlands.,Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6500 GA, Nijmegen, The Netherlands
| | - Y Elgersma
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus University Medical Center, 3015 CN, Rotterdam, The Netherlands
| | - N Katsanis
- Center for Human Disease Modeling, Duke University, Durham, NC, 27701, USA
| | - H G Brunner
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, 6500 GA, The Netherlands. .,Department of Clinical Genetics and School for Oncology & Developmental Biology (GROW), Maastricht University Medical Center, 6202 AZ, Maastricht, The Netherlands.
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Zou J, Zhang B, Gutmann DH, Wong M. Postnatal reduction of tuberous sclerosis complex 1 expression in astrocytes and neurons causes seizures in an age-dependent manner. Epilepsia 2017; 58:2053-2063. [PMID: 29023667 DOI: 10.1111/epi.13923] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2017] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Epilepsy is one of the most prominent symptoms of tuberous sclerosis complex (TSC), a genetic disorder, and may be related to developmental defects resulting from impaired TSC1 or TSC2 gene function in astrocytes and neurons. Inactivation of the Tsc1 gene driven by a glial-fibrillary acidic protein (GFAP) promoter during embryonic brain development leads to widespread pathologic effects on astrocytes and neurons, culminating in severe, progressive epilepsy in mice (Tsc1GFAP-Cre mice). However, the developmental timing and cellular specificity relevant to epileptogenesis in this model has not been well defined. The present study evaluates the effect of postnatal Tsc1 gene inactivation on pathologic features of astrocytes and neurons and development of epilepsy. METHODS An inducible Tsc1 knock-out mouse was created utilizing a tamoxifen-driven GFAP-CreER line (Tsc1GFAP-CreER mice) with TSC1 reduction induced postnatally at 2 and 6 weeks of age, and compared to conventional Tsc1GFAP-Cre mice with prenatal TSC1 reduction. Western blotting, immunohistochemistry, histology, and video-electroencephalography (EEG) assessed mechanistic target of rapamycin (mTOR) pathway activation, astrogliosis, neuronal organization, and spontaneous seizures, respectively. RESULTS Tsc1 gene inactivation at 2 weeks of age was sufficient to cause astrogliosis and mild epilepsy in Tsc1GFAP-CreER mice, but the phenotype was much less severe than that observed with prenatal Tsc1 gene inactivation in Tsc1GFAP-Cre mice. Both astrocytes and neurons were affected by prenatal and postnatal Tsc1 gene activation to a degree similar to the severity of epilepsy, suggesting that both cellular types may contribute to epileptogenesis. SIGNIFICANCE These findings support a model in which the developmental timing of TSC1 loss dictates the severity of neuronal and glial abnormalities and resulting epilepsy.
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Affiliation(s)
- Jia Zou
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, U.S.A
| | - Bo Zhang
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, U.S.A
| | - David H Gutmann
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, U.S.A
| | - Michael Wong
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, U.S.A
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RHEB1 insufficiency in aged male mice is associated with stress-induced seizures. GeroScience 2017; 39:557-570. [PMID: 28891034 DOI: 10.1007/s11357-017-9997-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 08/24/2017] [Indexed: 02/06/2023] Open
Abstract
The mechanistic target of rapamycin (mTOR), a protein kinase, is a central regulator of mammalian metabolism and physiology. Protein mTOR complex 1 (mTORC1) functions as a major sensor for the nutrient, energy, and redox state of a cell and is activated by ras homolog enriched in brain (RHEB1), a GTP-binding protein. Increased activation of mTORC1 pathway has been associated with developmental abnormalities, certain form of epilepsy (tuberous sclerosis), and cancer. Clinically, those mTOR-related disorders are treated with the mTOR inhibitor rapamycin and its rapalogs. Because the effects of chronic interference with mTOR signaling in the aged brain are yet unknown, we used a genetic strategy to interfere with mTORC1 signaling selectively by introducing mutations of Rheb1 into the mouse. We created conventional knockout (Rheb1 +/- ) and gene trap (Rheb1 Δ/+ ) mutant mouse lines. Rheb1-insufficient mice with different combinations of mutant alleles were monitored over a time span of 2 years. The mice did not show any behavioral/neurological changes during the first 18 months of age. However, after aging (> 18 months of age), both the Rheb1 +/- and Rheb1 Δ /- hybrid males developed rare stress-induced seizures, whereas Rheb1 +/- and Rheb1 Δ /- females and Rheb1 Δ/+ and Rheb1 Δ/Δ mice of both genders did not show any abnormality. Our findings suggest that chronic intervention with mTORC1 signaling in the aged brain might be associated with major adverse events.
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Borrie SC, Brems H, Legius E, Bagni C. Cognitive Dysfunctions in Intellectual Disabilities: The Contributions of the Ras-MAPK and PI3K-AKT-mTOR Pathways. Annu Rev Genomics Hum Genet 2017; 18:115-142. [DOI: 10.1146/annurev-genom-091416-035332] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Sarah C. Borrie
- Department of Human Genetics, KU Leuven, 3000 Leuven, Belgium
| | - Hilde Brems
- Department of Human Genetics, KU Leuven, 3000 Leuven, Belgium
| | - Eric Legius
- Department of Human Genetics, KU Leuven, 3000 Leuven, Belgium
| | - Claudia Bagni
- Department of Human Genetics, KU Leuven, 3000 Leuven, Belgium
- Department of Fundamental Neuroscience, University of Lausanne, 1005 Lausanne, Switzerland
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00173 Rome, Italy
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Aronica E, Bauer S, Bozzi Y, Caleo M, Dingledine R, Gorter JA, Henshall DC, Kaufer D, Koh S, Löscher W, Louboutin JP, Mishto M, Norwood BA, Palma E, Poulter MO, Terrone G, Vezzani A, Kaminski RM. Neuroinflammatory targets and treatments for epilepsy validated in experimental models. Epilepsia 2017; 58 Suppl 3:27-38. [PMID: 28675563 DOI: 10.1111/epi.13783] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2017] [Indexed: 12/16/2022]
Abstract
A large body of evidence that has accumulated over the past decade strongly supports the role of inflammation in the pathophysiology of human epilepsy. Specific inflammatory molecules and pathways have been identified that influence various pathologic outcomes in different experimental models of epilepsy. Most importantly, the same inflammatory pathways have also been found in surgically resected brain tissue from patients with treatment-resistant epilepsy. New antiseizure therapies may be derived from these novel potential targets. An essential and crucial question is whether targeting these molecules and pathways may result in anti-ictogenesis, antiepileptogenesis, and/or disease-modification effects. Therefore, preclinical testing in models mimicking relevant aspects of epileptogenesis is needed to guide integrated experimental and clinical trial designs. We discuss the most recent preclinical proof-of-concept studies validating a number of therapeutic approaches against inflammatory mechanisms in animal models that could represent novel avenues for drug development in epilepsy. Finally, we suggest future directions to accelerate preclinical to clinical translation of these recent discoveries.
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Affiliation(s)
- Eleonora Aronica
- Department of (Neuro)Pathology, Academic Medical Center, Amsterdam, The Netherlands.,Swammerdam Institute for Life Sciences, Center for Neuroscience University of Amsterdam, Amsterdam, The Netherlands.,SEIN-Stichting Epilepsie Instellingen Nederland, Heemstede, The Netherlands
| | - Sebastian Bauer
- Department of Neurology, Philipps University, Marburg, Germany.,Department of Neurology, Epilepsy Center Frankfurt Rhine-Main, Goethe University, Frankfurt am Main, Germany
| | - Yuri Bozzi
- Neuroscience Institute, National Research Council (CNR), Pisa, Italy.,Laboratory of Molecular Neuropathology, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Matteo Caleo
- Neuroscience Institute, National Research Council (CNR), Pisa, Italy
| | - Raymond Dingledine
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia, U.S.A
| | - Jan A Gorter
- Swammerdam Institute for Life Sciences, Center for Neuroscience University of Amsterdam, Amsterdam, The Netherlands
| | - David C Henshall
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Daniela Kaufer
- Helen Wills Neuroscience Institute, UC Berkeley, Berkeley, California, U.S.A
| | - Sookyong Koh
- Department of Pediatrics, Emory University, Atlanta, Georgia, U.S.A
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany
| | - Jean-Pierre Louboutin
- Department of Basic Medical Sciences, University of the West Indies, Kingston, Jamaica.,Gene Therapy Program, University of Pennsylvania, Philadelphia, Pennsylvania, U.S.A
| | - Michele Mishto
- Charite University Medicine Berlin, Germany.,Berlin Institute of Health, Berlin, Germany
| | - Braxton A Norwood
- Department of Neurology, Philipps University, Marburg, Germany.,Neuroscience Division, Expesicor LLC, Kalispell, Montana, U.S.A
| | - Eleonora Palma
- Department of Physiology and Pharmacology, University of Rome La Sapienza, Rome, Italy
| | - Michael O Poulter
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
| | - Gaetano Terrone
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Annamaria Vezzani
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
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Morabito G, Giannelli SG, Ordazzo G, Bido S, Castoldi V, Indrigo M, Cabassi T, Cattaneo S, Luoni M, Cancellieri C, Sessa A, Bacigaluppi M, Taverna S, Leocani L, Lanciego JL, Broccoli V. AAV-PHP.B-Mediated Global-Scale Expression in the Mouse Nervous System Enables GBA1 Gene Therapy for Wide Protection from Synucleinopathy. Mol Ther 2017; 25:2727-2742. [PMID: 28882452 DOI: 10.1016/j.ymthe.2017.08.004] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 08/05/2017] [Accepted: 08/07/2017] [Indexed: 02/06/2023] Open
Abstract
The lack of technology for direct global-scale targeting of the adult mouse nervous system has hindered research on brain processing and dysfunctions. Currently, gene transfer is normally achieved by intraparenchymal viral injections, but these injections target a restricted brain area. Herein, we demonstrated that intravenous delivery of adeno-associated virus (AAV)-PHP.B viral particles permeated and diffused throughout the neural parenchyma, targeting both the central and the peripheral nervous system in a global pattern. We then established multiple procedures of viral transduction to control gene expression or inactivate gene function exclusively in the adult nervous system and assessed the underlying behavioral effects. Building on these results, we established an effective gene therapy strategy to counteract the widespread accumulation of α-synuclein deposits throughout the forebrain in a mouse model of synucleinopathy. Transduction of A53T-SCNA transgenic mice with AAV-PHP.B-GBA1 restored physiological levels of the enzyme, reduced α-synuclein pathology, and produced significant behavioral recovery. Finally, we provided evidence that AAV-PHP.B brain penetration does not lead to evident dysfunctions in blood-brain barrier integrity or permeability. Altogether, the AAV-PHP.B viral platform enables non-invasive, widespread, and long-lasting global neural expression of therapeutic genes, such as GBA1, providing an invaluable approach to treat neurodegenerative diseases with diffuse brain pathology such as synucleinopathies.
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Affiliation(s)
- Giuseppe Morabito
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy; University of Milano-Bicocca, 20126 Milan, Italy
| | - Serena G Giannelli
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Gabriele Ordazzo
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Simone Bido
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Valerio Castoldi
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), San Raffaele Scientific Institute, Milan, Italy; University Vita-Salute San Raffaele, 20132 Milan, Italy
| | - Marzia Indrigo
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Tommaso Cabassi
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Stefano Cattaneo
- Neuroimmunology Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Mirko Luoni
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy; University Vita-Salute San Raffaele, 20132 Milan, Italy
| | - Cinzia Cancellieri
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Alessandro Sessa
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Marco Bacigaluppi
- Neuroimmunology Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Stefano Taverna
- Neuroimmunology Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Letizia Leocani
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), San Raffaele Scientific Institute, Milan, Italy; University Vita-Salute San Raffaele, 20132 Milan, Italy
| | - José L Lanciego
- Department of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain; Centro de Investigacion Biomedica en Red en Enfermedades Neurodegenerativas (CiberNed), Pamplona, Spain
| | - Vania Broccoli
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy; National Research Council (CNR), Institute of Neuroscience, 20129 Milan, Italy.
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37
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An mTOuR of Epilepsy in Tuberous Sclerosis Complex. Epilepsy Curr 2017; 17:84-85. [DOI: 10.5698/1535-7511.17.2.84] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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38
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Sahin M, Henske EP, Manning BD, Ess KC, Bissler JJ, Klann E, Kwiatkowski DJ, Roberds SL, Silva AJ, Hillaire-Clarke CS, Young LR, Zervas M, Mamounas LA. Advances and Future Directions for Tuberous Sclerosis Complex Research: Recommendations From the 2015 Strategic Planning Conference. Pediatr Neurol 2016; 60:1-12. [PMID: 27267556 PMCID: PMC4921275 DOI: 10.1016/j.pediatrneurol.2016.03.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 03/24/2016] [Indexed: 11/17/2022]
Abstract
On March 10 to March 12, 2015, the National Institute of Neurological Disorders and Stroke and the Tuberous Sclerosis Alliance sponsored a workshop in Bethesda, Maryland, to assess progress and new opportunities for research in tuberous sclerosis complex with the goal of updating the 2003 Research Plan for Tuberous Sclerosis (http://www.ninds.nih.gov/about_ninds/plans/tscler_research_plan.htm). In addition to the National Institute of Neurological Disorders and Stroke and Tuberous Sclerosis Alliance, participants in the strategic planning effort and workshop included representatives from six other Institutes of the National Institutes of Health, the Department of Defense Tuberous Sclerosis Complex Research Program, and a broad cross-section of basic scientists and clinicians with expertise in tuberous sclerosis complex along with representatives from the pharmaceutical industry. Here we summarize the outcomes from the extensive premeeting deliberations and final workshop recommendations, including (1) progress in the field since publication of the initial 2003 research plan for tuberous sclerosis complex, (2) the key gaps, needs, and challenges that hinder progress in tuberous sclerosis complex research, and (3) a new set of research priorities along with specific recommendations for addressing the major challenges in each priority area. The new research plan is organized around both short-term and long-term goals with the expectation that progress toward specific objectives can be achieved within a five to ten year time frame.
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Affiliation(s)
- Mustafa Sahin
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts.
| | - Elizabeth P Henske
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Brendan D Manning
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Kevin C Ess
- Vanderbilt Kennedy Center for Research on Human Development, Department of Pediatrics, Vanderbilt University, Nashville, Tennessee
| | - John J Bissler
- University of Tennessee Health Science Center, Le Bonheur Children's Hospital and St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Eric Klann
- Center for Neural Science, New York University, New York, New York
| | - David J Kwiatkowski
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | | | - Alcino J Silva
- Departments of Neurobiology, Psychiatry and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California at Los Angeles, Los Angeles, California
| | - Coryse St Hillaire-Clarke
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - Lisa R Young
- Division of Pulmonary Medicine, Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee; Division of Allergy, Pulmonary, and Critical Care, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Mark Zervas
- Department of Neuroscience, Amgen Inc, Cambridge, Massachusetts
| | - Laura A Mamounas
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland.
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39
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The mTOR signalling cascade: paving new roads to cure neurological disease. Nat Rev Neurol 2016; 12:379-92. [PMID: 27340022 DOI: 10.1038/nrneurol.2016.81] [Citation(s) in RCA: 262] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Defining the multiple roles of the mechanistic (formerly 'mammalian') target of rapamycin (mTOR) signalling pathway in neurological diseases has been an exciting and rapidly evolving story of bench-to-bedside translational research that has spanned gene mutation discovery, functional experimental validation of mutations, pharmacological pathway manipulation, and clinical trials. Alterations in the dual contributions of mTOR - regulation of cell growth and proliferation, as well as autophagy and cell death - have been found in developmental brain malformations, epilepsy, autism and intellectual disability, hypoxic-ischaemic and traumatic brain injuries, brain tumours, and neurodegenerative disorders. mTOR integrates a variety of cues, such as growth factor levels, oxygen levels, and nutrient and energy availability, to regulate protein synthesis and cell growth. In line with the positioning of mTOR as a pivotal cell signalling node, altered mTOR activation has been associated with a group of phenotypically diverse neurological disorders. To understand how altered mTOR signalling leads to such divergent phenotypes, we need insight into the differential effects of enhanced or diminished mTOR activation, the developmental context of these changes, and the cell type affected by altered signalling. A particularly exciting feature of the tale of mTOR discovery is that pharmacological mTOR inhibitors have shown clinical benefits in some neurological disorders, such as tuberous sclerosis complex, and are being considered for clinical trials in epilepsy, autism, dementia, traumatic brain injury, and stroke.
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40
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Citraro R, Leo A, Constanti A, Russo E, De Sarro G. mTOR pathway inhibition as a new therapeutic strategy in epilepsy and epileptogenesis. Pharmacol Res 2016; 107:333-343. [DOI: 10.1016/j.phrs.2016.03.039] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/23/2016] [Accepted: 03/31/2016] [Indexed: 12/24/2022]
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Abstract
Focal cortical dysplasia is a common cause of medication resistant epilepsy. A better understanding of its presentation, pathophysiology and consequences have helped us improved its treatment and outcome. This paper reviews the most recent classification, pathophysiology and imaging findings in clinical research as well as the knowledge gained from studying genetic and lesional animal models of focal cortical dysplasia. This review of this recently gained knowledge will most likely help develop new research models and new therapeutic targets for patients with epilepsy associated with focal cortical dysplasia.
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42
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Fuso A, Iyer AM, van Scheppingen J, Maccarrone M, Scholl T, Hainfellner JA, Feucht M, Jansen FE, Spliet WG, Krsek P, Zamecnik J, Mühlebner A, Aronica E. Promoter-Specific Hypomethylation Correlates with IL-1β Overexpression in Tuberous Sclerosis Complex (TSC). J Mol Neurosci 2016; 59:464-70. [PMID: 27122151 PMCID: PMC4972849 DOI: 10.1007/s12031-016-0750-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 03/24/2016] [Indexed: 01/04/2023]
Abstract
In tuberous sclerosis complex (TSC), overexpression of numerous genes associated with inflammation has been observed. Among different proinflammatory cytokines, interleukin-1β (IL-1β) has been shown to be significantly involved in epileptogenesis and maintenance of seizures. Recent evidence indicates that IL-1β gene expression can be regulated by DNA methylation of its promoter. In the present study, we hypothesized that hypomethylation in the promoter region of the IL-1β gene may underlie its overexpression observed in TSC brain tissue. Bisulfite sequencing was used to study the methylation status of the promoter region of the IL-1β gene in TSC and control samples. We identified hypomethylation in the promoter region of the IL-1β gene in TSC samples. IL-1β is overexpressed in tubers, and gene expression is correlated with promoter hypomethylation at CpG and non-CpG sites. Our results provide the first evidence of epigenetic modulation of the IL-1β signaling in TSC. Thus, strategies that target epigenetic alterations could offer new therapeutic avenues to control the persistent activation of interleukin-1β-mediated inflammatory signaling in TSC brain.
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Affiliation(s)
- A Fuso
- European Center for Brain Research (CERC)/IRCCS Santa Lucia Foundation, Via del Fosso di Fiorano 64-65, 00143, Rome, Italy
| | - A M Iyer
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - J van Scheppingen
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - M Maccarrone
- European Center for Brain Research (CERC)/IRCCS Santa Lucia Foundation, Via del Fosso di Fiorano 64-65, 00143, Rome, Italy.,Department of Medicine, Campus Bio-Medico University of Rome, Rome, Italy
| | - T Scholl
- Department of Pediatrics, Medical University Vienna, Vienna, Austria
| | - J A Hainfellner
- Institute of Neurology, Medical University Vienna, Vienna, Austria
| | - M Feucht
- Department of Pediatrics, Medical University Vienna, Vienna, Austria
| | - F E Jansen
- Department of Pediatric Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - W G Spliet
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - P Krsek
- Department of Pediatric Neurology, 2nd Faculty of Medicine, Charles University, Motol University Hospital, Prague, Czech Republic
| | - J Zamecnik
- Department of Pathology, 2nd Faculty of Medicine, Charles University, Motol University Hospital, Prague, Czech Republic
| | - A Mühlebner
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.,Department of Pediatrics, Medical University Vienna, Vienna, Austria
| | - E Aronica
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. .,Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands. .,Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands.
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43
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Early onset epileptic encephalopathy or genetically determined encephalopathy with early onset epilepsy? Lessons learned from TSC. Eur J Paediatr Neurol 2016; 20:203-211. [PMID: 26758984 DOI: 10.1016/j.ejpn.2015.12.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 12/01/2015] [Accepted: 12/13/2015] [Indexed: 01/12/2023]
Abstract
BACKGROUND In tuberous sclerosis complex (TSC) a relationship has been shown between early and refractory seizures and intellectual disability. However, it is uncertain whether epilepsy in TSC is simply a marker in infants who are destined to develop an encephalopathic process or if seizures play a causal role in developing an encephalopathy. METHODS This paper summarizes the key points discussed during a European TSC workshop held in Rome, and reviews the experimental and clinical evidence in support of the two theories. RESULTS/CONCLUSION There are many factors that influence the appearance of both early seizure onset and the encephalopathy resulting in neurodevelopmental deficits. Experimental studies show that as a consequence of the TSC genes mutation, mammalian target of Rapamycin (mTOR) overactivation determines an alteration in cellular morphology with cytomegalic neurons, altered synaptogenesis and an imbalance between excitation/inhibition, thus providing a likely neuroanatomical substrate for the early appearance of refractory seizures and for the encephalopathic process. At the clinical level, early signs of altered developmental trajectories are often unrecognized before 12 months of age. Evidence from experimental research shows that encephalopathy in TSC might have a genetic cause, and mTOR activation caused by TSC gene mutation can be directly responsible for the early appearance of seizures and encephalopathy.
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44
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Tee AR, Sampson JR, Pal DK, Bateman JM. The role of mTOR signalling in neurogenesis, insights from tuberous sclerosis complex. Semin Cell Dev Biol 2016; 52:12-20. [PMID: 26849906 DOI: 10.1016/j.semcdb.2016.01.040] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 01/05/2016] [Accepted: 01/25/2016] [Indexed: 11/30/2022]
Abstract
Understanding the development and function of the nervous system is one of the foremost aims of current biomedical research. The nervous system is generated during a relatively short period of intense neurogenesis that is orchestrated by a number of key molecular signalling pathways. Even subtle defects in the activity of these molecules can have serious repercussions resulting in neurological, neurodevelopmental and neurocognitive problems including epilepsy, intellectual disability and autism. Tuberous sclerosis complex (TSC) is a monogenic disease characterised by these problems and by the formation of benign tumours in multiple organs, including the brain. TSC is caused by mutations in the TSC1 or TSC2 gene leading to activation of the mechanistic target of rapamycin (mTOR) signalling pathway. A desire to understand the neurological manifestations of TSC has stimulated research into the role of the mTOR pathway in neurogenesis. In this review we describe TSC neurobiology and how the use of animal model systems has provided insights into the roles of mTOR signalling in neuronal differentiation and migration. Recent progress in this field has identified novel mTOR pathway components regulating neuronal differentiation. The roles of mTOR signalling and aberrant neurogenesis in epilepsy are also discussed. Continuing efforts to understand mTOR neurobiology will help to identify new therapeutic targets for TSC and other neurological diseases.
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Affiliation(s)
- Andrew R Tee
- Institute of Cancer & Genetics, Cardiff University School of Medicine, Institute of Medical Genetics Building, Heath Park, Cardiff CF14 4XN UK
| | - Julian R Sampson
- Institute of Cancer & Genetics, Cardiff University School of Medicine, Institute of Medical Genetics Building, Heath Park, Cardiff CF14 4XN UK
| | - Deb K Pal
- Department of Basic & Clinical Neurosciences, Institute of Psychiatry, Psychology & Neuroscience, King's College, London SE5 8RX UK
| | - Joseph M Bateman
- Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London SE1 1UL UK.
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45
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Lee DY. Roles of mTOR Signaling in Brain Development. Exp Neurobiol 2015; 24:177-85. [PMID: 26412966 PMCID: PMC4580744 DOI: 10.5607/en.2015.24.3.177] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 09/02/2015] [Accepted: 09/02/2015] [Indexed: 12/18/2022] Open
Abstract
mTOR is a serine/threonine kinase composed of multiple protein components. Intracellular signaling of mTOR complexes is involved in many of physiological functions including cell survival, proliferation and differentiation through the regulation of protein synthesis in multiple cell types. During brain development, mTOR-mediated signaling pathway plays a crucial role in the process of neuronal and glial differentiation and the maintenance of the stemness of neural stem cells. The abnormalities in the activity of mTOR and its downstream signaling molecules in neural stem cells result in severe defects of brain developmental processes causing a significant number of brain disorders, such as pediatric brain tumors, autism, seizure, learning disability and mental retardation. Understanding the implication of mTOR activity in neural stem cells would be able to provide an important clue in the development of future brain developmental disorder therapies.
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Affiliation(s)
- Da Yong Lee
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
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46
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Wang T, de Kok L, Willemsen R, Elgersma Y, Borst JGG. In vivo synaptic transmission and morphology in mouse models of Tuberous sclerosis, Fragile X syndrome, Neurofibromatosis type 1, and Costello syndrome. Front Cell Neurosci 2015; 9:234. [PMID: 26190969 PMCID: PMC4490249 DOI: 10.3389/fncel.2015.00234] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Accepted: 06/08/2015] [Indexed: 01/01/2023] Open
Abstract
Defects in the rat sarcoma viral oncogene homolog (Ras)/extracellular-signal-regulated kinase and the phosphatidylinositol 3-kinase-mammalian target of rapamycin (mTOR) signaling pathways are responsible for several neurodevelopmental disorders. These disorders are an important cause for intellectual disability; additional manifestations include autism spectrum disorder, seizures, and brain malformations. Changes in synaptic function are thought to underlie the neurological conditions associated with these syndromes. We therefore studied morphology and in vivo synaptic transmission of the calyx of Held synapse, a relay synapse in the medial nucleus of the trapezoid body (MNTB) of the auditory brainstem, in mouse models of tuberous sclerosis complex (TSC), Fragile X syndrome (FXS), Neurofibromatosis type 1 (NF1), and Costello syndrome. Calyces from both Tsc1+/- and from Fmr1 knock-out (KO) mice showed increased volume and surface area compared to wild-type (WT) controls. In addition, in Fmr1 KO animals a larger fraction of calyces showed complex morphology. In MNTB principal neurons of Nf1+/- mice the average delay between EPSPs and APs was slightly smaller compared to WT controls, which could indicate an increased excitability. Otherwise, no obvious changes in synaptic transmission, or short-term plasticity were observed during juxtacellular recordings in any of the four lines. Our results in these four mutants thus indicate that abnormalities of mTOR or Ras signaling do not necessarily result in changes in in vivo synaptic transmission.
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Affiliation(s)
- Tiantian Wang
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam Rotterdam, Netherlands
| | - Laura de Kok
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam Rotterdam, Netherlands
| | - Rob Willemsen
- Department of Clinical Genetics, Erasmus MC, University Medical Center Rotterdam Rotterdam, Netherlands
| | - Ype Elgersma
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam Rotterdam, Netherlands ; ENCORE Expertise Center for Neurodevelopmental disorders, Erasmus MC, University Medical Center Rotterdam Rotterdam, Netherlands
| | - J Gerard G Borst
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam Rotterdam, Netherlands
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47
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Kirschstein T, Köhling R. Animal models of tumour-associated epilepsy. J Neurosci Methods 2015; 260:109-17. [PMID: 26092434 DOI: 10.1016/j.jneumeth.2015.06.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 06/05/2015] [Accepted: 06/08/2015] [Indexed: 01/26/2023]
Abstract
Brain tumours cause a sizeable proportion of epilepsies in adulthood, and actually can be etiologically responsible also for childhood epilepsies. Conversely, seizures are often first clinical signs of a brain tumour. Nevertheless, several issues of brain-tumour associated seizures and epilepsies are far from understood, or clarified regarding clinical consensus. These include both the specific mechanisms of epileptogenesis related to different tumour types, the possible relationship between malignancy and seizure emergence, the interaction between tumour mass and surrounding neuronal networks, and - not least - the best treatment options depending on different tumour types. To investigate these issues, experimental models of tumour-induced epilepsies are necessary. This review concentrates on the description of currently used models, focusing on methodological aspects. It highlights advantages and shortcomings of these models, and identifies future experimental challenges.
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Affiliation(s)
- Timo Kirschstein
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Gertrudenstrasse 9, 18057 Rostock, Germany
| | - Rüdiger Köhling
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Gertrudenstrasse 9, 18057 Rostock, Germany.
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Overwater IE, Bindels-de Heus K, Rietman AB, ten Hoopen LW, Vergouwe Y, Moll HA, de Wit MCY. Epilepsy in children with tuberous sclerosis complex: Chance of remission and response to antiepileptic drugs. Epilepsia 2015; 56:1239-45. [DOI: 10.1111/epi.13050] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2015] [Indexed: 01/16/2023]
Affiliation(s)
- Iris E. Overwater
- Department of Neurology; Erasmus MC-Sophia Children's Hospital; Rotterdam The Netherlands
- ENCORE TSC Expertise Center; Erasmus MC-Sophia Children's Hospital; Rotterdam The Netherlands
| | - Karen Bindels-de Heus
- ENCORE TSC Expertise Center; Erasmus MC-Sophia Children's Hospital; Rotterdam The Netherlands
- Department of Pediatrics; Erasmus MC-Sophia Children's Hospital; Rotterdam The Netherlands
| | - André B. Rietman
- Department of Neurology; Erasmus MC-Sophia Children's Hospital; Rotterdam The Netherlands
- ENCORE TSC Expertise Center; Erasmus MC-Sophia Children's Hospital; Rotterdam The Netherlands
| | - Leontine W. ten Hoopen
- ENCORE TSC Expertise Center; Erasmus MC-Sophia Children's Hospital; Rotterdam The Netherlands
- Department of Child and Adolescent Psychiatry/Psychology; Erasmus MC-Sophia Children's Hospital; Rotterdam The Netherlands
| | - Yvonne Vergouwe
- Department of Public Health; Erasmus MC Rotterdam; Rotterdam The Netherlands
| | - Henriette A. Moll
- Department of Pediatrics; Erasmus MC-Sophia Children's Hospital; Rotterdam The Netherlands
| | - Marie-Claire Y. de Wit
- Department of Neurology; Erasmus MC-Sophia Children's Hospital; Rotterdam The Netherlands
- ENCORE TSC Expertise Center; Erasmus MC-Sophia Children's Hospital; Rotterdam The Netherlands
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49
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Wong M, Roper SN. Genetic animal models of malformations of cortical development and epilepsy. J Neurosci Methods 2015; 260:73-82. [PMID: 25911067 DOI: 10.1016/j.jneumeth.2015.04.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 04/03/2015] [Accepted: 04/08/2015] [Indexed: 12/31/2022]
Abstract
Malformations of cortical development constitute a variety of pathological brain abnormalities that commonly cause severe, medically-refractory epilepsy, including focal lesions, such as focal cortical dysplasia, heterotopias, and tubers of tuberous sclerosis complex, and diffuse malformations, such as lissencephaly. Although some cortical malformations result from environmental insults during cortical development in utero, genetic factors are increasingly recognized as primary pathogenic factors across the entire spectrum of malformations. Genes implicated in causing different cortical malformations are involved in a variety of physiological functions, but many are focused on regulation of cell proliferation, differentiation, and neuronal migration. Advances in molecular genetic methods have allowed the engineering of increasingly sophisticated animal models of cortical malformations and associated epilepsy. These animal models have identified some common mechanistic themes shared by a number of different cortical malformations, but also revealed the diversity and complexity of cellular and molecular mechanisms that lead to the development of the pathological lesions and resulting epileptogenesis.
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Affiliation(s)
- Michael Wong
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Steven N Roper
- Department of Neurosurgery, University of Florida, Gainesville, FL 32610, USA
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50
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Crino PB. mTOR signaling in epilepsy: insights from malformations of cortical development. Cold Spring Harb Perspect Med 2015; 5:5/4/a022442. [PMID: 25833943 DOI: 10.1101/cshperspect.a022442] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Over the past decade enhanced activation of the mammalian target of rapamycin (mTOR)-signaling cascade has been identified in focal malformations of cortical development (MCD) subtypes, which have been collectively referred to as "mTORopathies." Mutations in mTOR regulatory genes (e.g., TSC1, TSC2, AKT3, DEPDC5) have been associated with several focal MCD highly associated with epilepsy such as tuberous sclerosis complex (TSC), hemimegalencephaly (HME; brain malformation associated with dramatic enlargement of one brain hemisphere), and cortical dysplasia. mTOR plays important roles in the regulation of cell division, growth, and survival, and, thus, aberrant activation of the cascade during cortical development can cause dramatic alterations in cell size, cortical lamination, and axon and dendrite outgrowth often observed in focal MCD. Although it is widely believed that structural alterations induced by hyperactivated mTOR signaling are critical for epileptogenesis, newer evidence suggests that mTOR activation on its own may enhance neuronal excitability. Clinical trials with mTOR inhibitors have shown efficacy in the treatment of seizures associated with focal MCD.
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Affiliation(s)
- Peter B Crino
- Shriners Hospital Pediatric Research Center and Department of Neurology, Temple University, Philadelphia, Pennsylvania 19140
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