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Ravizza T, Scheper M, Di Sapia R, Gorter J, Aronica E, Vezzani A. mTOR and neuroinflammation in epilepsy: implications for disease progression and treatment. Nat Rev Neurosci 2024; 25:334-350. [PMID: 38531962 DOI: 10.1038/s41583-024-00805-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2024] [Indexed: 03/28/2024]
Abstract
Epilepsy remains a major health concern as anti-seizure medications frequently fail, and there is currently no treatment to stop or prevent epileptogenesis, the process underlying the onset and progression of epilepsy. The identification of the pathological processes underlying epileptogenesis is instrumental to the development of drugs that may prevent the generation of seizures or control pharmaco-resistant seizures, which affect about 30% of patients. mTOR signalling and neuroinflammation have been recognized as critical pathways that are activated in brain cells in epilepsy. They represent a potential node of biological convergence in structural epilepsies with either a genetic or an acquired aetiology. Interventional studies in animal models and clinical studies give strong support to the involvement of each pathway in epilepsy. In this Review, we focus on available knowledge about the pathophysiological features of mTOR signalling and the neuroinflammatory brain response, and their interactions, in epilepsy. We discuss mitigation strategies for each pathway that display therapeutic effects in experimental and clinical epilepsy. A deeper understanding of these interconnected molecular cascades could enhance our strategies for managing epilepsy. This could pave the way for new treatments to fill the gaps in the development of preventative or disease-modifying drugs, thus overcoming the limitations of current symptomatic medications.
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Affiliation(s)
- Teresa Ravizza
- Department of Acute Brain and Cardiovascular Injury, Mario Negri Institute for Pharmacological Research IRCCS, Milano, Italy
| | - Mirte Scheper
- Department of (Neuro)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Rossella Di Sapia
- Department of Acute Brain and Cardiovascular Injury, Mario Negri Institute for Pharmacological Research IRCCS, Milano, Italy
| | - Jan Gorter
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands.
| | - Annamaria Vezzani
- Department of Acute Brain and Cardiovascular Injury, Mario Negri Institute for Pharmacological Research IRCCS, Milano, Italy.
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2
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Al-Dalahmah O, Sosunov AA, Sun Y, Liu Y, Madden N, Connolly ES, Troy CM, McKhann GM, Goldman JE. The Matrix Receptor CD44 Is Present in Astrocytes throughout the Human Central Nervous System and Accumulates in Hypoxia and Seizures. Cells 2024; 13:129. [PMID: 38247821 PMCID: PMC10814649 DOI: 10.3390/cells13020129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 11/20/2023] [Accepted: 12/22/2023] [Indexed: 01/23/2024] Open
Abstract
In the mammalian isocortex, CD44, a cell surface receptor for extracellular matrix molecules, is present in pial-based and fibrous astrocytes of white matter but not in protoplasmic astrocytes. In the hominid isocortex, CD44+ astrocytes comprise the subpial "interlaminar" astrocytes, sending long processes into the cortex. The hippocampus also contains similar astrocytes. We have examined all levels of the human central nervous system and found CD44+ astrocytes in every region. Astrocytes in white matter and astrocytes that interact with large blood vessels but not with capillaries in gray matter are CD44+, the latter extending long processes into the parenchyma. Motor neurons in the brainstem and spinal cord, such as oculomotor, facial, hypoglossal, and in the anterior horn of the spinal cord, are surrounded by CD44+ processes, contrasting with neurons in the cortex, basal ganglia, and thalamus. We found CD44+ processes that intercalate between ependymal cells to reach the ventricle. We also found CD44+ astrocytes in the molecular layer of the cerebellar cortex. Protoplasmic astrocytes, which do not normally contain CD44, acquire it in pathologies like hypoxia and seizures. The pervasive and inducible expression of CD44 in astrocytes is a novel finding that lays the foundations for functional studies into the significance of CD44 in health and disease.
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Affiliation(s)
- Osama Al-Dalahmah
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY 10032, USA
| | - Alexander A. Sosunov
- Department of Neurosurgery, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY 10032, USA (E.S.C.)
| | - Yu Sun
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY 10032, USA
| | - Yang Liu
- Department of Pathology, Albany Medical Center, Albany, NY 12208, USA
| | - Nacoya Madden
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY 10032, USA
| | - E. Sander Connolly
- Department of Neurosurgery, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY 10032, USA (E.S.C.)
| | - Carol M. Troy
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY 10032, USA
- Department of Neurology, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY 10032, USA
- The Taub Institute, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Guy M. McKhann
- Department of Neurosurgery, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY 10032, USA (E.S.C.)
| | - James E. Goldman
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY 10032, USA
- The Taub Institute, Columbia University Irving Medical Center, New York, NY 10032, USA
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3
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Erdogan MA, Bozkurt MF, Erbas O. Effects of prenatal testosterone exposure on the development of autism-like behaviours in offspring of Wistar rats. Int J Dev Neurosci 2022; 83:201-215. [PMID: 36573444 DOI: 10.1002/jdn.10248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 12/05/2022] [Accepted: 12/22/2022] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND A neurodevelopmental disease, autism spectrum disorder (ASD) occurs in males three times more commonly than girls. Higher prenatal testosterone exposure may result in autistic-like behaviour in boys, according to earlier research. It is unclear how fetal testosterone affects the development of autism. In this study, we tested the hypothesis that prenatal testosterone exposure in an animal model may result in autistic behaviours by modifying serotonin, dopamine, IGF-1 and oxytocin levels. MATERIALS AND METHODS Group 1 (control, n = 6) and Group 2 (testosterone undecanoate, n = 6) of female rats were randomly assigned. For 2-3 days during the oestrus cycle, female rats were housed with a reproductive male (three females/one male). On the 10th day of gestation, rats in Group 1 received 1 ml/kg% 0.9 NaCl saline, whereas rats in Group 2 received 250 mg/kg testosterone undecanoate. Until weaning on postnatal day 21 (P21), the mothers were permitted to care for their pups. On P21, 40 littermates-10 male and female for control and 10 male and female from mothers that exposed to testosterone-were arbitrarily split up and housed. On P50, these mature rats were tested for their behaviour. The rats were then sacrificed. The brain tissue was subjected to histological examinations as well as biochemical tests for homovanillic acid (HVA), 5-Hydroxyindoleacetic acid (5-HIAA), oxytocin and insulin-like growth factor-1 (IGF-1). RESULTS The groups differed significantly in the behavioural examinations (three-chamber social test, passive avoidance learning analysis, open field test), with the testosterone-exposed groups exhibiting autistic symptoms to a higher extent. When compared with the control groups, testosterone exposure caused significant histological changes in the hippocampus CA1 and CA3 areas, including gliosis and cell death of neurons. In the testosterone-exposed groups, HVA, 5-HIAA and IGF-1 tissue expressions in the brain elevated, whereas oxytocin levels reduced. These findings point to a potential connection between neurodevelopmental disorders like ASD and exposure to testosterone during gestation. CONCLUSION Overall, we revealed that prenatal testosterone exposure led to autistic traits by elevating serotonin, dopamine and IGF-1 levels while lowering oxytocin levels.
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Affiliation(s)
- Mumin Alper Erdogan
- Department of Physiology, Faculty of Medicine, Izmir Katip Celebi University, Izmir, Turkey
| | - Mehmet Fatih Bozkurt
- Department of Pathology, Faculty of Veterinary Medicine, Afyon Kocatepe University, Afyon, Turkey
| | - Oytun Erbas
- Department of Physiology, Faculty of Medicine, Demiroglu Bilim University, Istanbul, Turkey
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4
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mTOR and HDAC2 are simultaneously activated during electrically induced kindling of seizures. Epilepsy Res 2022; 185:106991. [DOI: 10.1016/j.eplepsyres.2022.106991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/27/2022] [Accepted: 07/28/2022] [Indexed: 11/23/2022]
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5
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Park S, Zhu J, Jeong KH, Kim WJ. Adjudin prevents neuronal damage and neuroinflammation via inhibiting mTOR activation against pilocarpine-induced status epilepticus. Brain Res Bull 2022; 182:80-89. [PMID: 35182690 DOI: 10.1016/j.brainresbull.2022.02.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 01/23/2022] [Accepted: 02/14/2022] [Indexed: 11/02/2022]
Abstract
Inflammatory responses in the brain play an etiological role in the development of epilepsy, suggesting that finding novel molecules for controlling neuroinflammation may have clinical value in developing the disease-modifying strategies for epileptogenesis. Adjudin, a multi-functional small molecule compound, has pleiotropic effects, including anti-inflammatory properties. In the present study, we aimed to investigate the effects of adjudin on pilocarpine-induced status epilepticus (SE) and its role in the regulation of reactive gliosis and neuroinflammation. SE was induced in male C57BL/6 mice that were then treated with adjudin (50mg/kg) for 3 days after SE onset. Immunofluorescence staining, terminal deoxynucleotidyl transferase dUTP nick end labeling staining, and western blot analysis were used to evaluate the effects of adjudin treatment in the hippocampus after SE. Our results showed that adjudin treatment significantly mitigated apoptotic cell death in the hippocampus after SE onset. Moreover, adjudin treatment suppressed SE-induced glial activation and activation of mammalian target of rapamycin signaling in the hippocampus. Concomitantly, adjudin treatment significantly reduced SE-induced inflammatory processes, as confirmed by changes in the expression of inflammatory mediators such as tumor necrosis factor-α, interleukin-1β, and arginase-1. In conclusion, these findings suggest that adjudin may serve as a potential neuroprotective agent for preventing pathological mechanisms implicated in epileptogenesis.
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Affiliation(s)
- Soojin Park
- Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea; Brain Korea 21 Plus Project for Medical Science, Yonsei University, Seoul, Republic of Korea
| | - Jing Zhu
- Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea; Brain Korea 21 Plus Project for Medical Science, Yonsei University, Seoul, Republic of Korea
| | - Kyoung Hoon Jeong
- Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea; Epilepsy Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea.
| | - Won-Joo Kim
- Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea; Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
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6
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Twible C, Abdo R, Zhang Q. Astrocyte Role in Temporal Lobe Epilepsy and Development of Mossy Fiber Sprouting. Front Cell Neurosci 2021; 15:725693. [PMID: 34658792 PMCID: PMC8514632 DOI: 10.3389/fncel.2021.725693] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/02/2021] [Indexed: 11/13/2022] Open
Abstract
Epilepsy affects approximately 50 million people worldwide, with 60% of adult epilepsies presenting an onset of focal origin. The most common focal epilepsy is temporal lobe epilepsy (TLE). The role of astrocytes in the presentation and development of TLE has been increasingly studied and discussed within the literature. The most common histopathological diagnosis of TLE is hippocampal sclerosis. Hippocampal sclerosis is characterized by neuronal cell loss within the Cornu ammonis and reactive astrogliosis. In some cases, mossy fiber sprouting may be observed. Mossy fiber sprouting has been controversial in its contribution to epileptogenesis in TLE patients, and the mechanisms surrounding the phenomenon have yet to be elucidated. Several studies have reported that mossy fiber sprouting has an almost certain co-existence with reactive astrogliosis within the hippocampus under epileptic conditions. Astrocytes are known to play an important role in the survival and axonal outgrowth of central and peripheral nervous system neurons, pointing to a potential role of astrocytes in TLE and associated cellular alterations. Herein, we review the recent developments surrounding the role of astrocytes in the pathogenic process of TLE and mossy fiber sprouting, with a focus on proposed signaling pathways and cellular mechanisms, histological observations, and clinical correlations in human patients.
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Affiliation(s)
- Carolyn Twible
- Department of Pathology and Lab Medicine, Western University, London, ON, Canada
| | - Rober Abdo
- Department of Pathology and Lab Medicine, Western University, London, ON, Canada.,Department of Anatomy and Cell Biology, Western University, London, ON, Canada
| | - Qi Zhang
- Department of Pathology and Lab Medicine, Western University, London, ON, Canada.,Department of Pathology and Lab Medicine, London Health Sciences Centre, University Hospital, London, ON, Canada
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7
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Multi-omics in mesial temporal lobe epilepsy with hippocampal sclerosis: Clues into the underlying mechanisms leading to disease. Seizure 2021; 90:34-50. [DOI: 10.1016/j.seizure.2021.03.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 02/26/2021] [Accepted: 03/02/2021] [Indexed: 02/07/2023] Open
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8
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Ahmed MM, Carrel AJ, Cruz Del Angel Y, Carlsen J, Thomas AX, González MI, Gardiner KJ, Brooks-Kayal A. Altered Protein Profiles During Epileptogenesis in the Pilocarpine Mouse Model of Temporal Lobe Epilepsy. Front Neurol 2021; 12:654606. [PMID: 34122302 PMCID: PMC8194494 DOI: 10.3389/fneur.2021.654606] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 04/06/2021] [Indexed: 12/17/2022] Open
Abstract
Epilepsy is characterized by recurrent, spontaneous seizures and is a major contributor to the global burden of neurological disease. Although epilepsy can result from a variety of brain insults, in many cases the cause is unknown and, in a significant proportion of cases, seizures cannot be controlled by available treatments. Understanding the molecular alterations that underlie or are triggered by epileptogenesis would help to identify therapeutics to prevent or control progression to epilepsy. To this end, the moderate throughput technique of Reverse Phase Protein Arrays (RPPA) was used to profile changes in protein expression in a pilocarpine mouse model of acquired epilepsy. Levels of 54 proteins, comprising phosphorylation-dependent and phosphorylation-independent components of major signaling pathways and cellular complexes, were measured in hippocampus, cortex and cerebellum of mice at six time points, spanning 15 min to 2 weeks after induction of status epilepticus. Results illustrate the time dependence of levels of the commonly studied MTOR pathway component, pS6, and show, for the first time, detailed responses during epileptogenesis of multiple components of the MTOR, MAPK, JAK/STAT and apoptosis pathways, NMDA receptors, and additional cellular complexes. Also noted are time- and brain region- specific changes in correlations among levels of functionally related proteins affecting both neurons and glia. While hippocampus and cortex are primary areas studied in pilocarpine-induced epilepsy, cerebellum also shows significant time-dependent molecular responses.
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Affiliation(s)
- Md Mahiuddin Ahmed
- Department of Neurology, University of Colorado Alzheimer's and Cognition Center, Linda Crnic Institute for Down Syndrome, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Andrew J Carrel
- Division of Neurology and Translational Epilepsy Research Program, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States
| | - Yasmin Cruz Del Angel
- Division of Neurology and Translational Epilepsy Research Program, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States
| | - Jessica Carlsen
- Division of Neurology and Translational Epilepsy Research Program, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States
| | - Ajay X Thomas
- Division of Neurology and Translational Epilepsy Research Program, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States.,Section of Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States.,Section of Child Neurology, Texas Children's Hospital, Houston, TX, United States
| | - Marco I González
- Division of Neurology and Translational Epilepsy Research Program, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States
| | - Katheleen J Gardiner
- Department of Pediatrics, Linda Crnic Institute for Down Syndrome, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Amy Brooks-Kayal
- Division of Neurology and Translational Epilepsy Research Program, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States.,Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, United States.,Children's Hospital Colorado, Aurora, CO, United States.,Department of Neurology, University of California Davis School of Medicine, Sacramento, CA, United States
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9
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Deficiency of Microglial Autophagy Increases the Density of Oligodendrocytes and Susceptibility to Severe Forms of Seizures. eNeuro 2021; 8:ENEURO.0183-20.2021. [PMID: 33472865 PMCID: PMC7890520 DOI: 10.1523/eneuro.0183-20.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 12/11/2020] [Accepted: 01/02/2021] [Indexed: 12/14/2022] Open
Abstract
Excessive activation of mTOR in microglia impairs CNS homeostasis and causes severe epilepsy. Autophagy constitutes an important part of mTOR signaling. The contribution of microglial autophagy to CNS homeostasis and epilepsy remains to be determined. Here, we report that ATG7KO mice deficient for autophagy in microglia display a marked increase of myelination markers, a higher density of mature oligodendrocytes (ODCs), and altered lengths of the nodes of Ranvier. Moreover, we found that deficiency of microglial autophagy (ATG7KO) leads to increased seizure susceptibility in three seizure models (pilocarpine, kainic acid, and amygdala kindling). We demonstrated that ATG7KO mice develop severe generalized seizures and display nearly 100% mortality to convulsions induced by pilocarpine and kainic acid. In the amygdala kindling model, we observed significant facilitation of contralateral propagation of seizures, a process underlying the development of generalized seizures. Taken together, our results reveal impaired microglial autophagy as a novel mechanism underlying altered homeostasis of ODCs and increased susceptibility to severe and fatal generalized seizures.
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10
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Zimmer TS, Broekaart DWM, Gruber VE, van Vliet EA, Mühlebner A, Aronica E. Tuberous Sclerosis Complex as Disease Model for Investigating mTOR-Related Gliopathy During Epileptogenesis. Front Neurol 2020; 11:1028. [PMID: 33041976 PMCID: PMC7527496 DOI: 10.3389/fneur.2020.01028] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 08/06/2020] [Indexed: 12/13/2022] Open
Abstract
Tuberous sclerosis complex (TSC) represents the prototypic monogenic disorder of the mammalian target of rapamycin (mTOR) pathway dysregulation. It provides the rational mechanistic basis of a direct link between gene mutation and brain pathology (structural and functional abnormalities) associated with a complex clinical phenotype including epilepsy, autism, and intellectual disability. So far, research conducted in TSC has been largely neuron-oriented. However, the neuropathological hallmarks of TSC and other malformations of cortical development also include major morphological and functional changes in glial cells involving astrocytes, oligodendrocytes, NG2 glia, and microglia. These cells and their interglial crosstalk may offer new insights into the common neurobiological mechanisms underlying epilepsy and the complex cognitive and behavioral comorbidities that are characteristic of the spectrum of mTOR-associated neurodevelopmental disorders. This review will focus on the role of glial dysfunction, the interaction between glia related to mTOR hyperactivity, and its contribution to epileptogenesis in TSC. Moreover, we will discuss how understanding glial abnormalities in TSC might give valuable insight into the pathophysiological mechanisms that could help to develop novel therapeutic approaches for TSC or other pathologies characterized by glial dysfunction and acquired mTOR hyperactivation.
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Affiliation(s)
- Till S Zimmer
- Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | - Diede W M Broekaart
- Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | | | - Erwin A van Vliet
- Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands.,Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, Netherlands
| | - Angelika Mühlebner
- Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands.,Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, Netherlands
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11
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Decanoic acid inhibits mTORC1 activity independent of glucose and insulin signaling. Proc Natl Acad Sci U S A 2020; 117:23617-23625. [PMID: 32879008 PMCID: PMC7519326 DOI: 10.1073/pnas.2008980117] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The mTORC1 complex provides a critical role in cell function, regulating a variety of processes including growth and autophagy. mTORC1 signaling is hyperactivated in a range of common diseases including cancer, epilepsy, and neurodegenerative disorders. Hence, mTORC1 signaling provides an important target for regulation in many contexts. Here, we show that decanoic acid, a key component of a widely used medicinal diet, reduces mTORC1 activity. We identify this in a tractable model system, and validate it in ex vivo rat brain tissue and in human iPSC-derived astrocytes from patients with a clinically relevant disease. Thus, we provide insight into an easily accessible therapeutic approach for a range of diseases. Low-glucose and -insulin conditions, associated with ketogenic diets, can reduce the activity of the mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway, potentially leading to a range of positive medical and health-related effects. Here, we determined whether mTORC1 signaling is also a target for decanoic acid, a key component of the medium-chain triglyceride (MCT) ketogenic diet. Using a tractable model system, Dictyostelium, we show that decanoic acid can decrease mTORC1 activity, under conditions of constant glucose and in the absence of insulin, measured by phosphorylation of eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1). We determine that this effect of decanoic acid is dependent on a ubiquitin regulatory X domain-containing protein, mediating inhibition of a conserved Dictyostelium AAA ATPase, p97, a homolog of the human transitional endoplasmic reticulum ATPase (VCP/p97) protein. We then demonstrate that decanoic acid decreases mTORC1 activity in the absence of insulin and under high-glucose conditions in ex vivo rat hippocampus and in tuberous sclerosis complex (TSC) patient-derived astrocytes. Our data therefore indicate that dietary decanoic acid may provide a new therapeutic approach to down-regulate mTORC1 signaling.
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12
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Microglial mTOR is Neuronal Protective and Antiepileptogenic in the Pilocarpine Model of Temporal Lobe Epilepsy. J Neurosci 2020; 40:7593-7608. [PMID: 32868461 DOI: 10.1523/jneurosci.2754-19.2020] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 08/05/2020] [Accepted: 08/24/2020] [Indexed: 01/01/2023] Open
Abstract
Excessive activation of mammalian target of rapamycin (mTOR) signaling is epileptogenic in genetic epilepsy. However, the exact role of microglial mTOR in acquired epilepsy remains to be clarified. In the present study, we found that mTOR is strongly activated in microglia following excitatory injury elicited by status epilepticus. To determine the role of microglial mTOR signaling in excitatory injury and epileptogenesis, we generated mice with restrictive deletion of mTOR in microglia. Both male and female mice were used in the present study. We found that mTOR-deficient microglia lost their typical proliferative and inflammatory responses to excitatory injury, whereas the proliferation of astrocytes was preserved. In addition, mTOR-deficient microglia did not effectively engulf injured/dying neurons. More importantly, microglial mTOR-deficient mice displayed increased neuronal loss and developed more severe spontaneous seizures. These findings suggest that microglial mTOR plays a protective role in mitigating neuronal loss and attenuating epileptogenesis in the excitatory injury model of epilepsy.SIGNIFICANCE STATEMENT The mammalian target of rapamycin (mTOR) pathway is strongly implicated in epilepsy. However, the effect of mTOR inhibitors in preclinical models of acquired epilepsy is inconsistent. The broad presence of mTOR signaling in various brain cells could prevent mTOR inhibitors from achieving a net therapeutic effect. This conundrum has spurred further investigation of the cell type-specific effects of mTOR signaling in the CNS. We found that activation of microglial mTOR is antiepileptogenic. Thus, microglial mTOR activation represents a novel antiepileptogenic route that appears to parallel the proepileptogenic route of neuronal mTOR activation. This may explain why the net effect of mTOR inhibitors is paradoxical in the acquired models of epilepsy. Our findings could better guide the use of mTOR inhibitors in preventing acquired epilepsy.
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13
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Jeong KH, Cho KO, Lee MY, Kim SY, Kim WJ. Vascular endothelial growth factor receptor-3 regulates astroglial glutamate transporter-1 expression via mTOR activation in reactive astrocytes following pilocarpine-induced status epilepticus. Glia 2020; 69:296-309. [PMID: 32835451 DOI: 10.1002/glia.23897] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 07/19/2020] [Accepted: 07/22/2020] [Indexed: 12/13/2022]
Abstract
Recent evidence has shown that the vascular endothelial growth factor (VEGF) system plays a crucial role in several neuropathological processes. We previously reported an upregulation of VEGF-C and its receptor, VEGFR-3, in reactive astrocytes after the onset of status epilepticus (SE). However, it remains unknown, which molecules act as downstream signals following VEGFR-3 upregulation, and are involved in reactive astrogliosis after SE. Therefore, we investigated whether VEGFR-3 upregulation within reactive astrocytes is associated with the activation of mammalian target of rapamycin (mTOR) signaling, which we confirmed by assaying for the phosphorylated form of S6 protein (pS6), and whether VEGFR-3-mediated mTOR activation induces astroglial glutamate transporter-1 (GLT-1) expression in the hippocampus after pilocarpine-induced SE. We found that spatiotemporal expression of pS6 was consistent with VEGFR-3 expression in the hippocampus after SE, and that both pS6 and VEGFR-3 were highly expressed in SE-induced reactive astrocytes. Treatment with the mTOR inhibitor rapamycin decreased astroglial VEGFR-3 expression and GLT-1 expression after SE. Treatment with a selective inhibitor for VEGFR-3 attenuated astroglial pS6 expression as well as suppressed GLT-1 expression and astroglial reactivity in the hippocampus after SE. These findings demonstrate that VEGFR-3-mediated mTOR activation could contribute to the regulation of GLT-1 expression in reactive astrocytes during the subacute phase of epilepsy. In conclusion, the present study suggests that VEGFR-3 upregulation in reactive astrocytes may play a role in preventing hyperexcitability induced by continued seizure activity.
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Affiliation(s)
- Kyoung Hoon Jeong
- Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea.,Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Kyung-Ok Cho
- Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Department of Biomedicine & Health Sciences, The Catholic University of Korea, Seoul, Republic of Korea.,Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Mun-Yong Lee
- Department of Biomedicine & Health Sciences, The Catholic University of Korea, Seoul, Republic of Korea.,Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Department of Anatomy, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Seong Yun Kim
- Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Department of Biomedicine & Health Sciences, The Catholic University of Korea, Seoul, Republic of Korea.,Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Won-Joo Kim
- Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea
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14
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Liu JYW, Dzurova N, Al-Kaaby B, Mills K, Sisodiya SM, Thom M. Granule Cell Dispersion in Human Temporal Lobe Epilepsy: Proteomics Investigation of Neurodevelopmental Migratory Pathways. Front Cell Neurosci 2020; 14:53. [PMID: 32256318 PMCID: PMC7090224 DOI: 10.3389/fncel.2020.00053] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 02/21/2020] [Indexed: 12/23/2022] Open
Abstract
Granule cell dispersion (GCD) is a common pathological feature observed in the hippocampus of patients with Mesial Temporal Lobe Epilepsy (MTLE). Pathomechanisms underlying GCD remain to be elucidated, but one hypothesis proposes aberrant reactivation of neurodevelopmental migratory pathways, possibly triggered by febrile seizures. This study aims to compare the proteomes of basal and dispersed granule cells in the hippocampus of eight MTLE patients with GCD to identify proteins that may mediate GCD in MTLE. Quantitative proteomics identified 1,882 proteins, of which 29% were found in basal granule cells only, 17% in dispersed only and 54% in both samples. Bioinformatics analyses revealed upregulated proteins in dispersed samples were involved in developmental cellular migratory processes, including cytoskeletal remodeling, axon guidance and signaling by Ras homologous (Rho) family of GTPases (P < 0.01). The expression of two Rho GTPases, RhoA and Rac1, was subsequently explored in immunohistochemical and in situ hybridization studies involving eighteen MTLE cases with or without GCD, and three normal post mortem cases. In cases with GCD, most dispersed granule cells in the outer-granular and molecular layers have an elongated soma and bipolar processes, with intense RhoA immunolabeling at opposite poles of the cell soma, while most granule cells in the basal granule cell layer were devoid of RhoA. A higher percentage of cells expressing RhoA was observed in cases with GCD than without GCD (P < 0.004). In GCD cases, the percentage of cells expressing RhoA was significantly higher in the inner molecular layer than the granule cell layer (P < 0.026), supporting proteomic findings. In situ hybridization studies using probes against RHOA and RAC1 mRNAs revealed fine peri- and nuclear puncta in granule cells of all cases. The density of cells expressing RHOA mRNAs was significantly higher in the inner molecular layer of cases with GCD than without GCD (P = 0.05). In summary, our study has found limited evidence for ongoing adult neurogenesis in the hippocampus of patients with MTLE, but evidence of differential dysmaturation between dispersed and basal granule cells has been demonstrated, and elevated expression of Rho GTPases in dispersed granule cells may contribute to the pathomechanisms underpinning GCD in MTLE.
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Affiliation(s)
- Joan Y W Liu
- Division of Neuropathology, National Hospital for Neurology and Neurosurgery, London, United Kingdom.,Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom.,School of Life Sciences, University of Westminster, London, United Kingdom
| | - Natasha Dzurova
- School of Life Sciences, University of Westminster, London, United Kingdom
| | - Batoul Al-Kaaby
- Division of Neuropathology, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Kevin Mills
- Biological Mass Spectrometry Centre, UCL Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Sanjay M Sisodiya
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom.,Chalfont Centre for Epilepsy, Chalfont St Peter, United Kingdom
| | - Maria Thom
- Division of Neuropathology, National Hospital for Neurology and Neurosurgery, London, United Kingdom.,Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom
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15
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Wong M. The role of glia in epilepsy, intellectual disability, and other neurodevelopmental disorders in tuberous sclerosis complex. J Neurodev Disord 2019; 11:30. [PMID: 31838997 PMCID: PMC6913020 DOI: 10.1186/s11689-019-9289-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 11/11/2019] [Indexed: 01/12/2023] Open
Abstract
Background Tuberous sclerosis complex (TSC) is a genetic disorder characterized by severe neurological manifestations, including epilepsy, intellectual disability, autism, and a range of other behavioral and psychiatric symptoms, collectively referred to as TSC-associated neuropsychiatric disorders (TAND). Various tumors and hamartomas affecting different organs are the pathological hallmarks of the disease, especially cortical tubers of the brain, but specific cellular and molecular abnormalities, such as involving the mechanistic target of rapamycin (mTOR) pathway, have been identified that also cause or contribute to neurological manifestations of TSC independent of gross structural lesions. In particular, while neurons are immediate mediators of neurological symptoms, different types of glial cells have been increasingly recognized to play important roles in the phenotypes of TSC. Main body This review summarizes the literature supporting glial dysfunction from both mouse models and clinical studies of TSC. In particular, evidence for the role of astrocytes, microglia, and oligodendrocytes in the pathophysiology of epilepsy and TAND in TSC is analyzed. Therapeutic implications of targeting glia cells in developing novel treatments for the neurological manifestations of TSC are also considered. Conclusions Different types of glial cells have both cell autonomous effects and interactions with neurons and other cells that are involved in the pathophysiology of the neurological phenotype of TSC. Targeting glial-mediated mechanisms may represent a novel therapeutic approach for epilepsy and TAND in TSC patients.
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Affiliation(s)
- Michael Wong
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, 660 South Euclid Avenue, Box 8111, St. Louis, MO, 63110, USA.
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16
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Long Non-Coding RNAs and Related Molecular Pathways in the Pathogenesis of Epilepsy. Int J Mol Sci 2019; 20:ijms20194898. [PMID: 31581735 PMCID: PMC6801574 DOI: 10.3390/ijms20194898] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 09/27/2019] [Accepted: 10/02/2019] [Indexed: 02/07/2023] Open
Abstract
Epilepsy represents one of the most common neurological disorders characterized by abnormal electrical activity in the central nervous system (CNS). Recurrent seizures are the cardinal clinical manifestation. Although it has been reported that the underlying pathological processes include inflammation, changes in synaptic strength, apoptosis, and ion channels dysfunction, currently the pathogenesis of epilepsy is not yet completely understood. Long non-coding RNAs (lncRNAs), a class of long transcripts without protein-coding capacity, have emerged as regulatory molecules that are involved in a wide variety of biological processes. A growing number of studies reported that lncRNAs participate in the regulation of pathological processes of epilepsy and they are dysregulated during epileptogenesis. Moreover, an aberrant expression of lncRNAs linked to epilepsy has been observed both in patients and in animal models. In this review, we summarize latest advances concerning the mechanisms of action and the involvement of the most dysregulated lncRNAs in epilepsy. However, the functional roles of lncRNAs in the disease pathogenesis are still to be explored and we are only at the beginning. Additional studies are needed for the complete understanding of the underlying mechanisms and they would result in the use of lncRNAs as diagnostic biomarkers and novel therapeutic targets.
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17
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Avdic U, Ahl M, Öberg M, Ekdahl CT. Immune Profile in Blood Following Non-convulsive Epileptic Seizures in Rats. Front Neurol 2019; 10:701. [PMID: 31333561 PMCID: PMC6615316 DOI: 10.3389/fneur.2019.00701] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 06/14/2019] [Indexed: 12/14/2022] Open
Abstract
Non-convulsive status epilepticus (NCSE) is a prolonged epileptic seizure with subtle symptoms that may delay clinical diagnosis. Emerging experimental evidence shows brain pathology and epilepsy development following NCSE. New diagnostic/prognostic tools are therefore needed for earlier and better stratification of treatment. Here we examined whether NCSE initiates a peripheral immune response in blood serum from rats that experienced electrically-induced NCSE. ELISA analysis showed an acute transient increase in serum protein levels including interleukin-6 6 h post-NCSE, similar to the immune reaction in the brain. At 4 weeks post-NCSE, when 75% of rats subjected to NCSE had also developed spontaneous seizures, several immune proteins were altered. In particular, markers associated with microglia, macrophages and antigen presenting cells, such as CD68, MHCII, and galectin-3, were increased and the T-cell marker CD4 was decreased in serum compared to both non-stimulated controls and NCSE rats without spontaneous seizures, without correlation to interictal epileptiform activity. Analyses of serum following intracerebral injection of lipopolysaccharide (LPS) showed an acute increase in interleukin-6, but at 4 weeks unaltered levels of MHCII and galectin-3, an increase in CD8 and CD11b and a decrease in CD68. None of the increased serum protein levels after NCSE or LPS could be confirmed in spleen tissue. Our data identifies the possibility to detect peripheral changes in serum protein levels following NCSE, which may be related to the development of subsequent spontaneous seizures.
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Affiliation(s)
- Una Avdic
- Inflammation and Stem Cell Therapy Group, Division of Clinical Neurophysiology, Lund University, Lund, Sweden.,Department of Clinical Sciences, Epilepsy Center, Lund University, Lund, Sweden
| | - Matilda Ahl
- Inflammation and Stem Cell Therapy Group, Division of Clinical Neurophysiology, Lund University, Lund, Sweden.,Department of Clinical Sciences, Epilepsy Center, Lund University, Lund, Sweden
| | - Maria Öberg
- Inflammation and Stem Cell Therapy Group, Division of Clinical Neurophysiology, Lund University, Lund, Sweden.,Department of Clinical Sciences, Epilepsy Center, Lund University, Lund, Sweden
| | - Christine T Ekdahl
- Inflammation and Stem Cell Therapy Group, Division of Clinical Neurophysiology, Lund University, Lund, Sweden.,Department of Clinical Sciences, Epilepsy Center, Lund University, Lund, Sweden
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18
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ALG13 Deficiency Associated with Increased Seizure Susceptibility and Severity. Neuroscience 2019; 409:204-221. [DOI: 10.1016/j.neuroscience.2019.03.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/02/2019] [Accepted: 03/04/2019] [Indexed: 01/31/2023]
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19
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Zhao X, Liao Y, Morgan S, Mathur R, Feustel P, Mazurkiewicz J, Qian J, Chang J, Mathern GW, Adamo MA, Ritaccio AL, Gruenthal M, Zhu X, Huang Y. Noninflammatory Changes of Microglia Are Sufficient to Cause Epilepsy. Cell Rep 2019; 22:2080-2093. [PMID: 29466735 PMCID: PMC5880308 DOI: 10.1016/j.celrep.2018.02.004] [Citation(s) in RCA: 118] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 12/27/2017] [Accepted: 01/31/2018] [Indexed: 12/25/2022] Open
Abstract
Microglia are well known to play a critical role in maintaining brain homeostasis. However, their role in epileptogenesis has yet to be determined. Here, we demonstrate that elevated mTOR signaling in mouse microglia leads to phenotypic changes, including an amoeboid-like morphology, increased proliferation, and robust phagocytosis activity, but without a significant induction of pro-inflammatory cytokines. We further provide evidence that these noninflammatory changes in microglia disrupt homeostasis of the CNS, leading to reduced synapse density, marked microglial infiltration into hippocampal pyramidal layers, moderate neuronal degeneration, and massive proliferation of astrocytes. Moreover, the mice thus affected develop severe early-onset spontaneous recurrent seizures (SRSs). Therefore, we have revealed an epileptogenic mechanism that is independent of the microglial inflammatory response. Our data suggest that microglia could be an opportune target for epilepsy prevention.
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Affiliation(s)
- Xiaofeng Zhao
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, USA
| | - Yuan Liao
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY 12208, USA
| | - Shannon Morgan
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, USA
| | - Ramkumar Mathur
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY 12208, USA
| | - Paul Feustel
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, USA
| | - Joseph Mazurkiewicz
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, USA
| | - Jiang Qian
- Department of Pathology, Albany Medical College, Albany, NY 12208, USA
| | - Julia Chang
- Department of Neurosurgery, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Gary W Mathern
- Department of Neurosurgery, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Matthew A Adamo
- Department of Neurosurgery, Albany Medical College, Albany, NY 12208, USA
| | | | - Michael Gruenthal
- Department of Neurology, Albany Medical College, Albany, NY 12208, USA
| | - Xinjun Zhu
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY 12208, USA; Department of Medicine, Albany Medical College, Albany, NY 12208, USA
| | - Yunfei Huang
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, USA.
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20
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Glia activation of eukaryotic translation initiation factor 4e-binding protein 1 in temporal lobe epilepsy. Neuroreport 2019; 30:222-226. [PMID: 30672889 DOI: 10.1097/wnr.0000000000001188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This study was aimed to investigate whether 4e-binding protein 1 is activated during temporal lobe epileptogenesis. We used the hippocampus of patients with refractory temporal lobe epilepsy (TLE), diagnosed with hippocampal sclerosis (HS) or non-HS, to examine the distribution of phospho-4e-binding protein 1 (p4EBP1) by immunohistochemical staining (n=3-5). We also examined p4EBP1 in the kainic acid (KA)-induced mouse model of TLE before and after anticonvulsant treatment (n=3 per group). The results showed that the hippocampus of both patients with HS and KA mouse model displayed significantly upregulated p4EBP1 immunoreactivity in glial fibrillary acidic protein-positive astrocytes in hippocampus. Quantitative results showed that there is a 5.9-fold upregulation in the number of p4EBP1+glia-like cells in TLE group than control group (P<0.05). However, treatment with lamotrigine failed to suppress spontaneous seizures and did not affect the astrocytic distribution of p4EBP1 (P=0.73). Taken together, we investigated the spatiotemporal expression of p4EBP1 in the sclerotic hippocampus of both patients and a KA-induced mouse model and found glia activation of 4e-binding protein 1 in TLE. Our findings suggest that the upregulation of p4EBP1 in astrocytes may play a critical role in the pathogenesis of TLE.
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21
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Kwon JY, Jung UJ, Kim DW, Kim S, Moon GJ, Hong J, Jeon MT, Shin M, Chang JH, Kim SR. Beneficial Effects of Hesperetin in a Mouse Model of Temporal Lobe Epilepsy. J Med Food 2018; 21:1306-1309. [DOI: 10.1089/jmf.2018.4183] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Affiliation(s)
- Jae Young Kwon
- BK21 Plus KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu, Korea
| | - Un Ju Jung
- Department of Food Science and Nutrition, Pukyong National University, Busan, Korea
| | - Dong Woon Kim
- Department of Anatomy, Brain Research Institute, Chungnam National University School of Medicine, Daejeon, Korea
| | - Sehwan Kim
- BK21 Plus KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu, Korea
| | - Gyeong Joon Moon
- BK21 Plus KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu, Korea
| | - Jungwan Hong
- BK21 Plus KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu, Korea
| | - Min-Tae Jeon
- BK21 Plus KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu, Korea
| | - Minsang Shin
- Department of Microbiology, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Jeong Ho Chang
- Department of Biology Education, Kyungpook National University, Daegu, Korea
| | - Sang Ryong Kim
- BK21 Plus KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu, Korea
- Brain Science and Engineering Institute, Kyungpook National University, Daegu, Korea
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22
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Abstract
The World Health Organization classifies diffuse low-grade gliomas (DLGGs) are highly epileptogenic primary brain tumors; epileptic seizures occur in more than 90% of cases. Epileptic seizures and drug resistance progress during the course of DLGGs. The glioma-related epileptogenic mechanisms are multifactorial; epileptogenic foci lie within the infiltrated peritumoral neocortex. A short seizure duration before surgery and a large extent of resection are the main predictors of postoperative seizure control in DLGGs. A supratotal resection of a DLGG can improve postoperative seizure control. Epileptic seizure at diagnosis positively affects DLGGs malignant transformation and overall survival.
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Affiliation(s)
- Johan Pallud
- Department of Neurosurgery, Sainte-Anne Hospital, 1 rue Cabanis, Paris Cedex 14 75674, France; Paris Descartes University, Sorbonne Paris Cité, Paris, France; French Glioma Study Group, Réseau d'Etude des Gliomes, REG, Groland, France; Inserm, U894, Centre Psychiatrie et Neurosciences, Paris, France.
| | - Guy M McKhann
- Department of Neurological Surgery, Columbia University Medical Center, New York Presbyterian Hospital, New York, NY, USA
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23
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Kumar J, Solaiman A, Mahakkanukrauh P, Mohamed R, Das S. Sleep Related Epilepsy and Pharmacotherapy: An Insight. Front Pharmacol 2018; 9:1088. [PMID: 30319421 PMCID: PMC6171479 DOI: 10.3389/fphar.2018.01088] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 09/07/2018] [Indexed: 01/26/2023] Open
Abstract
In the last several decades, sleep-related epilepsy has drawn considerable attention among epileptologists and neuroscientists in the interest of new paradigms of the disease etiology, pathogenesis and management. Sleep-related epilepsy is nocturnal seizures that manifest solely during the sleep state. Sleep comprises two distinct stages i.e., non-rapid eye movement (NREM) and rapid eye movement (REM) that alternate every 90 min with NREM preceding REM. Current findings indicate that the sleep-related epilepsy manifests predominantly during the synchronized stages of sleep; NREM over REM stage. Sleep related hypermotor epilepsy (SHE), benign partial epilepsy with centrotemporal spikes or benign rolandic epilepsy (BECTS), and Panayiotopoulos Syndrome (PS) are three of the most frequently implicated epilepsies occurring during the sleep state. Although some familial types are described, others are seemingly sporadic occurrences. In the present review, we aim to discuss the predominance of sleep-related epilepsy during NREM, established familial links to the pathogenesis of SHE, BECTS and PS, and highlight the present available pharmacotherapy options.
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Affiliation(s)
- Jaya Kumar
- Department of Physiology, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
| | - Amro Solaiman
- Department of Anatomy, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
| | - Pasuk Mahakkanukrauh
- Department of Anatomy, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Excellence Centre in Forensic Osteology Research Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Rashidi Mohamed
- Department of Familty Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
| | - Srijit Das
- Department of Anatomy, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
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24
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Wong JKL, Gui H, Kwok M, Ng PW, Lui CHT, Baum L, Sham PC, Kwan P, Cherny SS. Rare variants and de novo variants in mesial temporal lobe epilepsy with hippocampal sclerosis. NEUROLOGY-GENETICS 2018; 4:e245. [PMID: 29904720 PMCID: PMC5999346 DOI: 10.1212/nxg.0000000000000245] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 04/13/2018] [Indexed: 12/03/2022]
Abstract
Objective We investigated the role of rare genetic variants and of de novo variants in the pathogenesis of mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS). Methods Whole-exome sequencing (WES) was performed in patients with MTLE-HS and their unaffected parents (trios). Genes or gene sets that were enriched with predicted damaging rare variants in the patients as compared to population controls were identified. Patients and their parents were compared to identify whether the variants were de novo or inherited. Results After quality control, WES data from 47 patients (26 female), including 23 complete trios, were available for analysis. Compared with population controls, significant enrichment of rare variants was observed in SEC24B. Integration of gene set data describing neuronal functions and psychiatric disorders showed enrichment signal on fragile X mental retardation protein (FMRP) targets. Twenty-one de novo variants were identified, with many known to cause neuropsychiatric disorders. The FMRP-targeted genes also carried more de novo variants. Inherited compound heterozygous and homozygous variants were identified. Conclusions The genetic architecture underlying MTHE-HS is complex. Multiple genes carrying de novo variants and rare variants among FMRP targets were identified, suggesting a pathogenic role. MTLE-HS and other neuropsychiatric disorders may have shared biology.
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Affiliation(s)
- John K L Wong
- Centre for Genomic Sciences and Department of Psychiatry (J.K.L.W., H.G., L.B., P.C.S., S.S.C.), Li Ka Shing Faculty of Medicine, The University of Hong Kong; Department of Medicine and Therapeutics (M.K., P.K.), The Chinese University of Hong Kong; Department of Medicine (P.W.N.), United Christian Hospital; Department of Medicine (C.H.T.L.), Queen Elizabeth Hospital, Hong Kong, China; Departments of Medicine and Neurology (P.K.), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Epidemiology and Preventive Medicine (S.S.C.) and Department of Anatomy and Anthropology (S.S.C.), Sackler Faculty of Medicine, Tel Aviv University, Israel; and The State Key Laboratory of Brain and Cognitive Sciences (P.C.S., S.S.C.)
| | - Hongsheng Gui
- Centre for Genomic Sciences and Department of Psychiatry (J.K.L.W., H.G., L.B., P.C.S., S.S.C.), Li Ka Shing Faculty of Medicine, The University of Hong Kong; Department of Medicine and Therapeutics (M.K., P.K.), The Chinese University of Hong Kong; Department of Medicine (P.W.N.), United Christian Hospital; Department of Medicine (C.H.T.L.), Queen Elizabeth Hospital, Hong Kong, China; Departments of Medicine and Neurology (P.K.), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Epidemiology and Preventive Medicine (S.S.C.) and Department of Anatomy and Anthropology (S.S.C.), Sackler Faculty of Medicine, Tel Aviv University, Israel; and The State Key Laboratory of Brain and Cognitive Sciences (P.C.S., S.S.C.)
| | - Maxwell Kwok
- Centre for Genomic Sciences and Department of Psychiatry (J.K.L.W., H.G., L.B., P.C.S., S.S.C.), Li Ka Shing Faculty of Medicine, The University of Hong Kong; Department of Medicine and Therapeutics (M.K., P.K.), The Chinese University of Hong Kong; Department of Medicine (P.W.N.), United Christian Hospital; Department of Medicine (C.H.T.L.), Queen Elizabeth Hospital, Hong Kong, China; Departments of Medicine and Neurology (P.K.), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Epidemiology and Preventive Medicine (S.S.C.) and Department of Anatomy and Anthropology (S.S.C.), Sackler Faculty of Medicine, Tel Aviv University, Israel; and The State Key Laboratory of Brain and Cognitive Sciences (P.C.S., S.S.C.)
| | - Ping Wing Ng
- Centre for Genomic Sciences and Department of Psychiatry (J.K.L.W., H.G., L.B., P.C.S., S.S.C.), Li Ka Shing Faculty of Medicine, The University of Hong Kong; Department of Medicine and Therapeutics (M.K., P.K.), The Chinese University of Hong Kong; Department of Medicine (P.W.N.), United Christian Hospital; Department of Medicine (C.H.T.L.), Queen Elizabeth Hospital, Hong Kong, China; Departments of Medicine and Neurology (P.K.), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Epidemiology and Preventive Medicine (S.S.C.) and Department of Anatomy and Anthropology (S.S.C.), Sackler Faculty of Medicine, Tel Aviv University, Israel; and The State Key Laboratory of Brain and Cognitive Sciences (P.C.S., S.S.C.)
| | - Colin H T Lui
- Centre for Genomic Sciences and Department of Psychiatry (J.K.L.W., H.G., L.B., P.C.S., S.S.C.), Li Ka Shing Faculty of Medicine, The University of Hong Kong; Department of Medicine and Therapeutics (M.K., P.K.), The Chinese University of Hong Kong; Department of Medicine (P.W.N.), United Christian Hospital; Department of Medicine (C.H.T.L.), Queen Elizabeth Hospital, Hong Kong, China; Departments of Medicine and Neurology (P.K.), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Epidemiology and Preventive Medicine (S.S.C.) and Department of Anatomy and Anthropology (S.S.C.), Sackler Faculty of Medicine, Tel Aviv University, Israel; and The State Key Laboratory of Brain and Cognitive Sciences (P.C.S., S.S.C.)
| | - Larry Baum
- Centre for Genomic Sciences and Department of Psychiatry (J.K.L.W., H.G., L.B., P.C.S., S.S.C.), Li Ka Shing Faculty of Medicine, The University of Hong Kong; Department of Medicine and Therapeutics (M.K., P.K.), The Chinese University of Hong Kong; Department of Medicine (P.W.N.), United Christian Hospital; Department of Medicine (C.H.T.L.), Queen Elizabeth Hospital, Hong Kong, China; Departments of Medicine and Neurology (P.K.), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Epidemiology and Preventive Medicine (S.S.C.) and Department of Anatomy and Anthropology (S.S.C.), Sackler Faculty of Medicine, Tel Aviv University, Israel; and The State Key Laboratory of Brain and Cognitive Sciences (P.C.S., S.S.C.)
| | - Pak Chung Sham
- Centre for Genomic Sciences and Department of Psychiatry (J.K.L.W., H.G., L.B., P.C.S., S.S.C.), Li Ka Shing Faculty of Medicine, The University of Hong Kong; Department of Medicine and Therapeutics (M.K., P.K.), The Chinese University of Hong Kong; Department of Medicine (P.W.N.), United Christian Hospital; Department of Medicine (C.H.T.L.), Queen Elizabeth Hospital, Hong Kong, China; Departments of Medicine and Neurology (P.K.), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Epidemiology and Preventive Medicine (S.S.C.) and Department of Anatomy and Anthropology (S.S.C.), Sackler Faculty of Medicine, Tel Aviv University, Israel; and The State Key Laboratory of Brain and Cognitive Sciences (P.C.S., S.S.C.)
| | - Patrick Kwan
- Centre for Genomic Sciences and Department of Psychiatry (J.K.L.W., H.G., L.B., P.C.S., S.S.C.), Li Ka Shing Faculty of Medicine, The University of Hong Kong; Department of Medicine and Therapeutics (M.K., P.K.), The Chinese University of Hong Kong; Department of Medicine (P.W.N.), United Christian Hospital; Department of Medicine (C.H.T.L.), Queen Elizabeth Hospital, Hong Kong, China; Departments of Medicine and Neurology (P.K.), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Epidemiology and Preventive Medicine (S.S.C.) and Department of Anatomy and Anthropology (S.S.C.), Sackler Faculty of Medicine, Tel Aviv University, Israel; and The State Key Laboratory of Brain and Cognitive Sciences (P.C.S., S.S.C.)
| | - Stacey S Cherny
- Centre for Genomic Sciences and Department of Psychiatry (J.K.L.W., H.G., L.B., P.C.S., S.S.C.), Li Ka Shing Faculty of Medicine, The University of Hong Kong; Department of Medicine and Therapeutics (M.K., P.K.), The Chinese University of Hong Kong; Department of Medicine (P.W.N.), United Christian Hospital; Department of Medicine (C.H.T.L.), Queen Elizabeth Hospital, Hong Kong, China; Departments of Medicine and Neurology (P.K.), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Epidemiology and Preventive Medicine (S.S.C.) and Department of Anatomy and Anthropology (S.S.C.), Sackler Faculty of Medicine, Tel Aviv University, Israel; and The State Key Laboratory of Brain and Cognitive Sciences (P.C.S., S.S.C.)
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Dysregulated long non-coding RNAs in the temporal lobe epilepsy mouse model. Seizure 2018; 58:110-119. [DOI: 10.1016/j.seizure.2018.04.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 04/05/2018] [Accepted: 04/11/2018] [Indexed: 02/07/2023] Open
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Talos DM, Jacobs LM, Gourmaud S, Coto CA, Sun H, Lim KC, Lucas TH, Davis KA, Martinez-Lage M, Jensen FE. Mechanistic target of rapamycin complex 1 and 2 in human temporal lobe epilepsy. Ann Neurol 2018; 83:311-327. [PMID: 29331082 DOI: 10.1002/ana.25149] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 01/09/2018] [Accepted: 01/10/2018] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Temporal lobe epilepsy (TLE) is a chronic epilepsy syndrome defined by seizures and progressive neurological disabilities, including cognitive impairments, anxiety, and depression. Here, human TLE specimens were investigated focusing on the mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) and complex 2 (mTORC2) activities in the brain, given that both pathways may represent unique targets for treatment. METHODS Surgically resected hippocampal and temporal lobe samples from therapy-resistant TLE patients were analyzed by western blotting to quantify the expression of established mTORC1 and mTORC2 activity markers and upstream or downstream signaling pathways involving the two complexes. Histological and immunohistochemical techniques were used to assess hippocampal and neocortical structural abnormalities and cell-specific expression of individual biomarkers. Samples from patients with focal cortical dysplasia (FCD) type II served as positive controls. RESULTS We found significantly increased expression of phospho-mTOR (Ser2448), phospho-S6 (Ser235/236), phospho-S6 (Ser240/244), and phospho-Akt (Ser473) in TLE samples compared to controls, consistent with activation of both mTORC1 and mTORC2. Our work identified the phosphoinositide 3-kinase and Ras/extracellular signal-regulated kinase signaling pathways as potential mTORC1 and mTORC2 upstream activators. In addition, we found that overactive mTORC2 signaling was accompanied by induction of two protein kinase B-dependent prosurvival pathways, as evidenced by increased inhibitory phosphorylation of forkhead box class O3a (Ser253) and glycogen synthase kinase 3 beta (Ser9). INTERPRETATION Our data demonstrate that mTOR signaling is significantly dysregulated in human TLE, offering new targets for pharmacological interventions. Specifically, clinically available drugs that suppress mTORC1 without compromising mTOR2 signaling, such as rapamycin and its analogs, may represent a new group of antiepileptogenic agents in TLE patients. Ann Neurol 2018;83:311-327.
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Affiliation(s)
- Delia M Talos
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
| | - Leah M Jacobs
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
| | - Sarah Gourmaud
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
| | - Carlos A Coto
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
| | - Hongyu Sun
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA.,Department of Neuroscience, Carleton University, Ottawa, ON, Canada
| | - Kuei-Cheng Lim
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
| | - Timothy H Lucas
- Department of Neurosurgery, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
| | - Kathryn A Davis
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
| | - Maria Martinez-Lage
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
| | - Frances E Jensen
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
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Navidhamidi M, Ghasemi M, Mehranfard N. Epilepsy-associated alterations in hippocampal excitability. Rev Neurosci 2018; 28:307-334. [PMID: 28099137 DOI: 10.1515/revneuro-2016-0059] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 11/03/2016] [Indexed: 11/15/2022]
Abstract
The hippocampus exhibits a wide range of epilepsy-related abnormalities and is situated in the mesial temporal lobe, where limbic seizures begin. These abnormalities could affect membrane excitability and lead to overstimulation of neurons. Multiple overlapping processes refer to neural homeostatic responses develop in neurons that work together to restore neuronal firing rates to control levels. Nevertheless, homeostatic mechanisms are unable to restore normal neuronal excitability, and the epileptic hippocampus becomes hyperexcitable or hypoexcitable. Studies show that there is hyperexcitability even before starting recurrent spontaneous seizures, suggesting although hippocampal hyperexcitability may contribute to epileptogenesis, it alone is insufficient to produce epileptic seizures. This supports the concept that the hippocampus is not the only substrate for limbic seizure onset, and a broader hyperexcitable limbic structure may contribute to temporal lobe epilepsy (TLE) seizures. Nevertheless, seizures also occur in conditions where the hippocampus shows a hypoexcitable phenotype. Since TLE seizures most often originate in the hippocampus, it could therefore be assumed that both hippocampal hypoexcitability and hyperexcitability are undesirable states that make the epileptic hippocampal network less stable and may, under certain conditions, trigger seizures.
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Olabarria M, Goldman JE. Disorders of Astrocytes: Alexander Disease as a Model. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2017; 12:131-152. [PMID: 28135564 DOI: 10.1146/annurev-pathol-052016-100218] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Astrocytes undergo important phenotypic changes in many neurological disorders, including strokes, trauma, inflammatory diseases, infectious diseases, and neurodegenerative diseases. We have been studying the astrocytes of Alexander disease (AxD), which is caused by heterozygous mutations in the GFAP gene, which is the gene that encodes the major astrocyte intermediate filament protein. AxD is a primary astrocyte disease because GFAP expression is specific to astrocytes in the central nervous system (CNS). The accumulation of extremely large amounts of GFAP causes many molecular changes in astrocytes, including proteasome inhibition, stress kinase activation, mechanistic target of rapamycin (mTOR) activation, loss of glutamate and potassium buffering capacity, loss of astrocyte coupling, and changes in cell morphology. Many of these changes appear to be common to astrocyte reactions in other neurological disorders. Using AxD to illuminate common mechanisms, we discuss the molecular pathology of AxD astrocytes and compare that to astrocyte pathology in other disorders.
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Affiliation(s)
- Markel Olabarria
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032; ,
| | - James E Goldman
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032; ,
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Pecoraro A, Arehart E, Gallentine W, Radtke R, Smith E, Pizoli C, Kansagra S, Abdelnour E, McLendon R, Mikati MA. Epilepsy in neurofibromatosis type 1. Epilepsy Behav 2017. [PMID: 28633092 DOI: 10.1016/j.yebeh.2017.05.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
OBJECTIVES To describe the characteristics of epilepsy in patients with Neurofibromatosis type 1 (NF1). METHODS Analysis of a cohort of consecutive NF1 patients seen in our NF1 clinic during a three-year period. RESULTS Of the 184 NF1 patients seen during that period, 26 had epilepsy and three had febrile seizures. Of the 26, 17 (65%) had localization-related epilepsy, seven of whom (41%) were drug resistant. Six (23%) had apparently primary generalized epilepsy (0/6 drug resistant), two (8%) Lennox-Gastaut syndrome, and one (4%) West syndrome (all three were drug-resistant). As compared to the patients with no epilepsy, those with epilepsy were more likely to have MRI findings of mesial temporal sclerosis (MTS) (23% vs. 5%, p=0.0064), and cerebral hemisphere tumors (31% vs. 10%, p=0.0079), but not of the other MRI findings including neurofibromatosis bright objects, or optic gliomas. Three of the six patients with MTS underwent temporal lobectomy with subsequent control of their seizures with confirmation of MTS on pathology in 3/3 and presence of coexisting focal cortical dysplasia (FCD) in 2/3. We also have observed three additional patients outside the above study with the association of NF1, MTS, and intractable epilepsy. SIGNIFICANCE Epilepsy is relatively common in NF1, often occurs in patients with brain tumors or with MTS which can coexist with FCD, can be associated with multiple types of epilepsy syndromes, and when localization-related is often drug-resistant. Patients with NF1 and MTS can respond to medial temporal lobectomy and may have coexisting medial temporal lobe cortical dysplasia.
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Affiliation(s)
- Anthony Pecoraro
- Duke University Medical Center, Division of Pediatric Neurology, Durham, NC 27710, United States
| | - Eric Arehart
- Duke University Medical Center, Division of Pediatric Neurology, Durham, NC 27710, United States
| | - William Gallentine
- Duke University Medical Center, Division of Pediatric Neurology, Durham, NC 27710, United States
| | - Rodney Radtke
- Duke University Medical Center, Department of Neurology, Durham, NC 27708, United States
| | - Edward Smith
- Duke University Medical Center, Division of Pediatric Neurology, Durham, NC 27710, United States
| | - Carolyn Pizoli
- Duke University Medical Center, Division of Pediatric Neurology, Durham, NC 27710, United States
| | - Sujay Kansagra
- Duke University Medical Center, Division of Pediatric Neurology, Durham, NC 27710, United States
| | - Elie Abdelnour
- Duke University Medical Center, Division of Pediatric Neurology, Durham, NC 27710, United States
| | - Roger McLendon
- Duke University Medical Center, Department of Pathology, Durham, NC 27708, United States
| | - Mohamad A Mikati
- Duke University Medical Center, Division of Pediatric Neurology, Durham, NC 27710, United States.
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Guo D, Zou J, Wong M. Rapamycin Attenuates Acute Seizure-induced Astrocyte Injury in Mice in Vivo. Sci Rep 2017; 7:2867. [PMID: 28588256 PMCID: PMC5460181 DOI: 10.1038/s41598-017-03032-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 04/21/2017] [Indexed: 11/12/2022] Open
Abstract
Astrocytes have been implicated in epileptogenesis and seizure-induced brain injury. Pathological studies reveal a variety of structural abnormalities in astrocytes, such as vacuolization and astrogliosis. While in vivo imaging methods have demonstrated rapid changes in astrocytes under a variety of physiological and pathological conditions, the acute effects of seizures on astrocyte morphology in vivo and corresponding mechanisms of seizure-induced astrocytic injury have not been documented. In this study, we utilized in vivo two-photon imaging to directly monitor the acute structural effects of kainate-induced seizures on cortical astrocytes. Kainate seizures cause an immediate, but transient, vacuolization of astrocytes, followed over several days by astrogliosis. These effects are prevented by pre- or post-treatment with rapamycin, indicating the mTOR pathway is involved in mediating seizure-induced astrocyte injury. These finding have clinical implications for mechanisms of seizure-induced astrocyte injury and potential therapeutic applications with mTOR inhibitors.
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Affiliation(s)
- Dongjun Guo
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Jia Zou
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Michael Wong
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, 63110, USA.
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Switon K, Kotulska K, Janusz-Kaminska A, Zmorzynska J, Jaworski J. Molecular neurobiology of mTOR. Neuroscience 2017; 341:112-153. [PMID: 27889578 DOI: 10.1016/j.neuroscience.2016.11.017] [Citation(s) in RCA: 276] [Impact Index Per Article: 39.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 11/09/2016] [Accepted: 11/13/2016] [Indexed: 01/17/2023]
Abstract
Mammalian/mechanistic target of rapamycin (mTOR) is a serine-threonine kinase that controls several important aspects of mammalian cell function. mTOR activity is modulated by various intra- and extracellular factors; in turn, mTOR changes rates of translation, transcription, protein degradation, cell signaling, metabolism, and cytoskeleton dynamics. mTOR has been repeatedly shown to participate in neuronal development and the proper functioning of mature neurons. Changes in mTOR activity are often observed in nervous system diseases, including genetic diseases (e.g., tuberous sclerosis complex, Pten-related syndromes, neurofibromatosis, and Fragile X syndrome), epilepsy, brain tumors, and neurodegenerative disorders (Alzheimer's disease, Parkinson's disease, and Huntington's disease). Neuroscientists only recently began deciphering the molecular processes that are downstream of mTOR that participate in proper function of the nervous system. As a result, we are gaining knowledge about the ways in which aberrant changes in mTOR activity lead to various nervous system diseases. In this review, we provide a comprehensive view of mTOR in the nervous system, with a special focus on the neuronal functions of mTOR (e.g., control of translation, transcription, and autophagy) that likely underlie the contribution of mTOR to nervous system diseases.
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Affiliation(s)
- Katarzyna Switon
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena Street, Warsaw 02-109, Poland
| | - Katarzyna Kotulska
- Department of Neurology and Epileptology, Children's Memorial Health Institute, Aleja Dzieci Polskich 20, Warsaw 04-730, Poland
| | | | - Justyna Zmorzynska
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena Street, Warsaw 02-109, Poland
| | - Jacek Jaworski
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena Street, Warsaw 02-109, Poland.
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32
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Klingebiel M, Dinekov M, Köhler C. Analysis of ribosomal protein S6 baseline phosphorylation and effect of tau pathology in the murine brain and human hippocampus. Brain Res 2017; 1659:121-135. [PMID: 28119058 DOI: 10.1016/j.brainres.2017.01.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 01/12/2017] [Accepted: 01/13/2017] [Indexed: 01/17/2023]
Abstract
We examined the distribution pattern of the phosphorylated 40S ribosomal subunit protein S6, a downstream target of the mTOR pathway, in the brains of 24-months-old human tau transgenic pR5 mice, non-transgenic littermates and in human hippocampi. We studied baseline levels of phosphorylated S6 and a possible effect of tau pathology. S6 phosphorylated at Ser235/236 (pS6Ser235/236) or Ser240/244 (pS6Ser240/244) has been used as a read-out of mTOR activity in several studies. The mTOR pathway regulates a wide variety of cellular functions including cell growth, ribosome biosynthesis, translational control and autophagy. Its dysregulation might underlie the neurodegenerative pathology of Alzheimer's disease and other tauopathies. pS6Ser235/236 and pS6Ser240/244 immunoreactivity in the mouse brain were widespread and similar distributed, but intensive pS6Ser235/236 immunoreactivity was more selective, especially highlighting certain brainstem regions. In the human hippocampus mainly granulovacuolar inclusions in neurons displayed pS6Ser235/236 immunoreactivity. In contrast, a considerable number of neurons displayed pS6Ser240/244 immunoreactivity in the cytoplasm without labeling of granulovacuolar inclusions. Except for a tendency of lower numbers of intensely phosphorylated S6-positive neurons in pR5 mice, the pattern of distribution of pS6Ser235/236 and pS6Ser240/244 immunoreactivity was largely unchanged when compared with non-transgenic mice and also when human hippocampi from AD cases and controls were compared. Similar to pR5 mice most neurons with hyper-phosphorylated tau in human hippocampi displayed no or only weak labeling for phosphorylated S6, suggesting that phosphorylated S6 is not especially associated with pathological tau, but is rather a feature of unaffected neurons.
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Affiliation(s)
- Maria Klingebiel
- Institute II for Anatomy, Medical Faculty, University of Cologne, Kerpener Str. 62, 50924 Cologne, Germany
| | - Maja Dinekov
- Institute II for Anatomy, Medical Faculty, University of Cologne, Kerpener Str. 62, 50924 Cologne, Germany
| | - Christoph Köhler
- Institute II for Anatomy, Medical Faculty, University of Cologne, Kerpener Str. 62, 50924 Cologne, Germany.
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Li D, Wang C, Yao Y, Chen L, Liu G, Zhang R, Liu Q, Shi FD, Hao J. mTORC1 pathway disruption ameliorates brain inflammation following stroke via a shift in microglia phenotype from M1 type to M2 type. FASEB J 2016; 30:3388-3399. [PMID: 27342766 DOI: 10.1096/fj.201600495r] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 06/14/2016] [Indexed: 11/11/2022]
Abstract
Inflammatory factors secreted by microglia play an important role in focal ischemic stroke. The mammalian target of rapamycin (mTOR) pathway is a known regulator of immune responses, but the role that mTORC1 signaling plays in poststroke neuroinflammation is not clear. To explore the relationship between microglial action in the mTORC1 pathway and the impact on stroke, we administered the mTORC1 inhibitors sirolimus and everolimus to mice. Presumably, disrupting the mTORC1 pathway after focal ischemic stroke should clarify the subsequent activity of microglia. For that purpose, we generated mice deficient in the regulatory associated protein of mTOR (Raptor) in microglia, whose mTORC1 signaling was blocked, by crossing Raptor loxed (Raptorflox/flox) mice with CX3CR1CreER mice, which express Cre recombinase under the control of the CX3C chemokine receptor 1 promoter. mTORC1 blockade reduced lesion size, improved motor function, dramatically decreased production of proinflammatory cytokines and chemokines, and reduced the number of M1 type microglia. Thus, mTORC1 blockade apparently attenuated behavioral deficits and poststroke inflammation after middle cerebral artery occlusion by preventing microglia polarization toward the M1 type.-Li, D., Wang, C., Yao, Y., Chen, L., Liu, G., Zhang, R., Liu, Q., Shi, F.-D., Hao, J. mTORC1 pathway disruption ameliorates brain inflammation following stroke via a shift in microglia phenotype from M1 type to M2 type.
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Affiliation(s)
- Daojing Li
- Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Chunjiong Wang
- Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
| | - Yang Yao
- Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Li Chen
- Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Guiyou Liu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Rongxin Zhang
- Department of Immunology, Tianjin Medical University, Tianjin, China; and
| | - Qiang Liu
- Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China; Department of Neurology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
| | - Fu-Dong Shi
- Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China; Department of Neurology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
| | - Junwei Hao
- Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China;
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Matsushita Y, Sakai Y, Shimmura M, Shigeto H, Nishio M, Akamine S, Sanefuji M, Ishizaki Y, Torisu H, Nakabeppu Y, Suzuki A, Takada H, Hara T. Hyperactive mTOR signals in the proopiomelanocortin-expressing hippocampal neurons cause age-dependent epilepsy and premature death in mice. Sci Rep 2016; 6:22991. [PMID: 26961412 PMCID: PMC4785342 DOI: 10.1038/srep22991] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 02/25/2016] [Indexed: 12/28/2022] Open
Abstract
Epilepsy is a frequent comorbidity in patients with focal cortical dysplasia (FCD). Recent studies utilizing massive sequencing data identified subsets of genes that are associated with epilepsy and FCD. AKT and mTOR-related signals have been recently implicated in the pathogenic processes of epilepsy and FCD. To clarify the functional roles of the AKT-mTOR pathway in the hippocampal neurons, we generated conditional knockout mice harboring the deletion of Pten (Pten-cKO) in Proopiomelanocortin-expressing neurons. The Pten-cKO mice developed normally until 8 weeks of age, then presented generalized seizures at 8–10 weeks of age. Video-monitored electroencephalograms detected paroxysmal discharges emerging from the cerebral cortex and hippocampus. These mice showed progressive hypertrophy of the dentate gyrus (DG) with increased expressions of excitatory synaptic markers (Psd95, Shank3 and Homer). In contrast, the expression of inhibitory neurons (Gad67) was decreased at 6–8 weeks of age. Immunofluorescence studies revealed the abnormal sprouting of mossy fibers in the DG of the Pten-cKO mice prior to the onset of seizures. The treatment of these mice with an mTOR inhibitor rapamycin successfully prevented the development of seizures and reversed these molecular phenotypes. These data indicate that the mTOR pathway regulates hippocampal excitability in the postnatal brain.
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Affiliation(s)
- Yuki Matsushita
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Yasunari Sakai
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Mitsunori Shimmura
- Department of Neurology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Hiroshi Shigeto
- Department of Neurology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Miki Nishio
- Division of Cancer Genetics, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Satoshi Akamine
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Masafumi Sanefuji
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Yoshito Ishizaki
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Hiroyuki Torisu
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Yusaku Nakabeppu
- Division of Neurofunctional Genomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Akira Suzuki
- Division of Cancer Genetics, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Hidetoshi Takada
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Toshiro Hara
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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Deletion of mTOR in Reactive Astrocytes Suppresses Chronic Seizures in a Mouse Model of Temporal Lobe Epilepsy. Mol Neurobiol 2016; 54:175-187. [PMID: 26732600 DOI: 10.1007/s12035-015-9590-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 11/29/2015] [Indexed: 01/28/2023]
Abstract
Germline and somatic mutations in key genes of the mammalian target of rapamycin (mTOR) pathway have been identified in seizure-associated disorders. mTOR mutations lead to aberrant activation of mTOR signaling, and, although affected neurons are critical for epileptogenesis, the role of mTOR activation in glial cells remains poorly understood. We previously reported a consistent activation of the mTOR pathway in astrocytes in the epileptic foci of temporal lobe epilepsy. In this study, it was demonstrated that mTOR deletion from reactive astrocytes prevents increases in seizure frequency over the disease course. By using a tamoxifen-inducible mTOR conditional knockout system and kainic acid, a model was developed that allowed astrocyte-specific mTOR gene deletion in mice with chronic epilepsy. Animals in which mTOR was deleted from 44 % of the astrocyte population exhibited a lower seizure frequency compared with controls. Down-regulation of mTOR significantly ameliorated astrogliosis in the sclerotic hippocampus but did not rescue mossy fiber sprouting. In cultured astrocytes, the mTOR pathway modulated the stability of the astroglial glutamate transporter 1 (Glt1) and influenced the ability of astrocytes to remove extracellular glutamate. Taken together, these data indicate that astrocytes with activated mTOR signaling may provide conditions that are favorable for spontaneous recurrent seizures.
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Maiese K. Targeting molecules to medicine with mTOR, autophagy and neurodegenerative disorders. Br J Clin Pharmacol 2015; 82:1245-1266. [PMID: 26469771 DOI: 10.1111/bcp.12804] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Revised: 10/11/2015] [Accepted: 10/13/2015] [Indexed: 12/14/2022] Open
Abstract
Neurodegenerative disorders are significantly increasing in incidence as the age of the global population continues to climb with improved life expectancy. At present, more than 30 million individuals throughout the world are impacted by acute and chronic neurodegenerative disorders with limited treatment strategies. The mechanistic target of rapamycin (mTOR), also known as the mammalian target of rapamycin, is a 289 kDa serine/threonine protein kinase that offers exciting possibilities for novel treatment strategies for a host of neurodegenerative diseases that include Alzheimer's disease, Parkinson's disease, Huntington's disease, epilepsy, stroke and trauma. mTOR governs the programmed cell death pathways of apoptosis and autophagy that can determine neuronal stem cell development, precursor cell differentiation, cell senescence, cell survival and ultimate cell fate. Coupled to the cellular biology of mTOR are a number of considerations for the development of novel treatments involving the fine control of mTOR signalling, tumourigenesis, complexity of the apoptosis and autophagy relationship, functional outcome in the nervous system, and the intimately linked pathways of growth factors, phosphoinositide 3-kinase (PI 3-K), protein kinase B (Akt), AMP activated protein kinase (AMPK), silent mating type information regulation two homologue one (Saccharomyces cerevisiae) (SIRT1) and others. Effective clinical translation of the cellular signalling mechanisms of mTOR offers provocative avenues for new drug development in the nervous system tempered only by the need to elucidate further the intricacies of the mTOR pathway.
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Affiliation(s)
- Kenneth Maiese
- Cellular and Molecular Signaling, Newark, New Jersey, 07101, USA.
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Abstract
Focal cortical dysplasias are common malformations of cerebral cortical development and are highly associated with medically intractable epilepsy. They have been classified into neuropathological subtypes (type Ia, Ib, IIa, IIb, and III) based on the severity of cytoarchitectural disruption--tangential or radial dispersion, or loss of laminar structure--and the presence of unique cells types such as cytomegalic neurons or balloon cells. Most focal cortical dysplasias can be identified on neuroimaging and many require resective epilepsy surgery to cure refractory seizures. The pathogenesis of focal cortical dysplasias remains to be defined, although there is recent evidence to suggest that focal cortical dysplasias arise from de novo somatic mutations occurring during brain development. Some focal cortical dysplasia subtypes show a link to the mammalian target of rapamycin signaling cascade; this has now extended to other cortical malformations, including hemimegalencephaly.
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Affiliation(s)
- Peter B Crino
- Department of Neurology, Shriners Hospital Pediatric Research Center and Temple University, Philadelphia, Pennsylvania
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38
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Robert SM, Buckingham SC, Campbell SL, Robel S, Holt KT, Ogunrinu-Babarinde T, Warren PP, White DM, Reid MA, Eschbacher JM, Berens ME, Lahti AC, Nabors LB, Sontheimer H. SLC7A11 expression is associated with seizures and predicts poor survival in patients with malignant glioma. Sci Transl Med 2015; 7:289ra86. [PMID: 26019222 PMCID: PMC4503260 DOI: 10.1126/scitranslmed.aaa8103] [Citation(s) in RCA: 189] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Glioma is the most common malignant primary brain tumor. Its rapid growth is aided by tumor-mediated glutamate release, creating peritumoral excitotoxic cell death and vacating space for tumor expansion. Glioma glutamate release may also be responsible for seizures, which complicate the clinical course for many patients and are often the presenting symptom. A hypothesized glutamate release pathway is the cystine/glutamate transporter System xc (-) (SXC), responsible for the cellular synthesis of glutathione (GSH). However, the relationship of SXC-mediated glutamate release, seizures, and tumor growth remains unclear. Probing expression of SLC7A11/xCT, the catalytic subunit of SXC, in patient and mouse-propagated tissues, we found that ~50% of patient tumors have elevated SLC7A11 expression. Compared with tumors lacking this transporter, in vivo propagated and intracranially implanted SLC7A11-expressing tumors grew faster, produced pronounced peritumoral glutamate excitotoxicity, induced seizures, and shortened overall survival. In agreement with animal data, increased SLC7A11 expression predicted shorter patient survival according to genomic data in the REMBRANDT (National Institutes of Health Repository for Molecular Brain Neoplasia Data) database. In a clinical pilot study, we used magnetic resonance spectroscopy to determine SXC-mediated glutamate release by measuring acute changes in glutamate after administration of the U.S. Food and Drug Administration-approved SXC inhibitor, sulfasalazine (SAS). In nine glioma patients with biopsy-confirmed SXC expression, we found that expression positively correlates with glutamate release, which is acutely inhibited with oral SAS. These data suggest that SXC is the major pathway for glutamate release from gliomas and that SLC7A11 expression predicts accelerated growth and tumor-associated seizures.
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Affiliation(s)
- Stephanie M Robert
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Susan C Buckingham
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Susan L Campbell
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Stefanie Robel
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Kenneth T Holt
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Toyin Ogunrinu-Babarinde
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Paula P Warren
- Division of Neuro-oncology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - David M White
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Meredith A Reid
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jenny M Eschbacher
- Cancer and Cell Biology Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Michael E Berens
- Cancer and Cell Biology Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Adrienne C Lahti
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Louis B Nabors
- Division of Neuro-oncology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Harald Sontheimer
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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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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Nguyen LH, Brewster AL, Clark ME, Regnier-Golanov A, Sunnen CN, Patil VV, D'Arcangelo G, Anderson AE. mTOR inhibition suppresses established epilepsy in a mouse model of cortical dysplasia. Epilepsia 2015; 56:636-46. [PMID: 25752454 DOI: 10.1111/epi.12946] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2015] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Hyperactivation of the mechanistic target of rapamycin (mTOR; also known as mammalian target of rapamycin) pathway has been demonstrated in human cortical dysplasia (CD) as well as in animal models of epilepsy. Although inhibition of mTOR signaling early in epileptogenesis suppressed epileptiform activity in the neuron subset-specific Pten knockout (NS-Pten KO) mouse model of CD, the effects of mTOR inhibition after epilepsy is fully established were not previously examined in this model. Here, we investigated whether mTOR inhibition suppresses epileptiform activity and other neuropathological correlates in adult NS-Pten KO mice with severe and well-established epilepsy. METHODS The progression of epileptiform activity, mTOR pathway dysregulation, and associated neuropathology with age in NS-Pten KO mice were evaluated using video-electroencephalography (EEG) recordings, Western blotting, and immunohistochemistry. A cohort of NS-Pten KO mice was treated with the mTOR inhibitor rapamycin (10 mg/kg i.p., 5 days/week) starting at postnatal week 9 and video-EEG monitored for epileptiform activity. Western blotting and immunohistochemistry were performed to evaluate the effects of rapamycin on the associated pathology. RESULTS Epileptiform activity worsened with age in NS-Pten KO mice, with parallel increases in the extent of hippocampal mTOR complex 1 and 2 (mTORC1 and mTORC2, respectively) dysregulation and progressive astrogliosis and microgliosis. Rapamycin treatment suppressed epileptiform activity, improved baseline EEG activity, and increased survival in severely epileptic NS-Pten KO mice. At the molecular level, rapamycin treatment was associated with a reduction in both mTORC1 and mTORC2 signaling and decreased astrogliosis and microgliosis. SIGNIFICANCE These findings reveal a wide temporal window for successful therapeutic intervention with rapamycin in the NS-Pten KO mouse model, and they support mTOR inhibition as a candidate therapy for established, late-stage epilepsy associated with CD and genetic dysregulation of the mTOR pathway.
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Affiliation(s)
- Lena H Nguyen
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, U.S.A; The Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, U.S.A; The Gordon and Mary Cain Pediatric Neurology Research Foundation Laboratories, Texas Children's Hospital, Houston, Texas, U.S.A
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Abstract
Despite a large number of available medical options, many individuals with epilepsy are refractory to existing therapies that mainly target neurotransmitter or ion channel activity. A growing body of preclinical data has uncovered a molecular pathway that appears crucial in many genetic and acquired epilepsy syndromes. The mammalian target of rapamycin (mTOR) pathway regulates a number of cellular processes required in the growth, metabolism, structure, and cell-cell interactions of neurons and glia. Rapamycin and similar compounds inhibit mTOR complex 1 and decrease seizures, delay seizure development, or prevent epileptogenesis in many animal models of mTOR hyperactivation. However, the exact mechanisms by which mTOR inhibition drives decreased seizure activity have not been completely determined. Nonetheless, these preclinical data have led to limited use in humans with epilepsy due to tuberous sclerosis complex and polyhydramnios, megalencephaly, and symptomatic epilepsy with promising results. Currently, larger controlled studies are underway using mTOR inhibitors in individuals with tuberous sclerosis complex and intractable epilepsy.
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Affiliation(s)
- Adam P. Ostendorf
- Department of Neurology, Washington University School of Medicine, Box 8111, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Michael Wong
- Department of Neurology, Washington University School of Medicine, Box 8111, 660 South Euclid Avenue, St. Louis, MO 63110, USA,Hope Center for Neurological Disorders, Washington University School of Medicine, Box 8111, 660 South Euclid Avenue, St. Louis, MO 63110, USA
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Giorgi FS, Biagioni F, Lenzi P, Frati A, Fornai F. The role of autophagy in epileptogenesis and in epilepsy-induced neuronal alterations. J Neural Transm (Vienna) 2014; 122:849-62. [DOI: 10.1007/s00702-014-1312-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 09/09/2014] [Indexed: 12/12/2022]
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Evidence for mTOR pathway activation in a spectrum of epilepsy-associated pathologies. Acta Neuropathol Commun 2014; 2:71. [PMID: 25005575 PMCID: PMC4230418 DOI: 10.1186/2051-5960-2-71] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 06/06/2014] [Indexed: 02/07/2023] Open
Abstract
INTRODUCTION Activation of the mTOR pathway has been linked to the cytopathology and epileptogenicity of malformations, specifically Focal Cortical Dysplasia (FCD) and Tuberous Sclerosis (TSC). Experimental and clinical trials have shown than mTOR inhibitors have anti-epileptogenic effects in TS. Dysmorphic neurones and balloon cells are hallmarks of FCDIIb and TSC, but similar cells are also occasionally observed in other acquired epileptogenic pathologies, including hippocampal sclerosis (HS) and Rasmussen's encephalitis (RE). Our aim was to explore mTOR pathway activation in a range of epilepsy-associated pathologies and in lesion-negative cases. RESULTS 50 epilepsy surgical pathologies were selected including HS ILAE type 1 with (5) and without dysmorphic neurones (4), FCDIIa (1), FCDIIb (5), FCDIIIa (5), FCDIIIb (3), FCDIIId (3), RE (5) and cortex adjacent to cavernoma (1). We also included pathology-negative epilepsy cases; temporal cortex (7), frontal cortex (2), paired frontal cortical samples with different ictal activity according to intracranial EEG recordings (4), cortex with acute injuries from electrode tracks (5) and additionally non-epilepsy surgical controls (3). Immunohistochemistry for phospho-S6 (pS6) ser240/244 and ser235/236 and double-labelling for Iba1, neurofilament, GFAP, GFAPdelta, doublecortin, and nestin were performed. Predominant neuronal labelling was observed with pS6 ser240/244 and glial labelling with pS6 ser235/236 in all pathology types but with evidence for co-expression in a proportion of cells in all pathologies. Intense labelling of dysmorphic neurones and balloon cells was observed in FCDIIb, but dysmorphic neurones were also labelled in RE and HS. There was no difference in pS6 labelling in paired samples according to ictal activity. Double-labelling immunofluorescent studies further demonstrated the co-localisation of pS6 with nestin, doublecortin, GFAPdelta in populations of small, immature neuroglial cells in a range of epilepsy pathologies. CONCLUSIONS Although mTOR activation has been more studied in the FCDIIb and TSC, our observations suggest this pathway is activated in a variety of epilepsy-associated pathologies, and in varied cell types including dysmorphic neurones, microglia and immature cell types. There was no definite evidence from our studies to suggest that pS6 expression is directly related to disease activity.
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mTOR Hyperactivation in Down Syndrome Hippocampus Appears Early During Development. J Neuropathol Exp Neurol 2014; 73:671-83. [DOI: 10.1097/nen.0000000000000083] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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Russo E, Follesa P, Citraro R, Camastra C, Donato A, Isola D, Constanti A, De Sarro G, Donato G. The mTOR signaling pathway and neuronal stem/progenitor cell proliferation in the hippocampus are altered during the development of absence epilepsy in a genetic animal model. Neurol Sci 2014; 35:1793-9. [DOI: 10.1007/s10072-014-1842-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 05/20/2014] [Indexed: 10/25/2022]
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Widespread activation of microglial cells in the hippocampus of chronic epileptic rats correlates only partially with neurodegeneration. Brain Struct Funct 2014; 220:2423-39. [PMID: 24878824 DOI: 10.1007/s00429-014-0802-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 05/14/2014] [Indexed: 12/30/2022]
Abstract
Activation of microglial cells (brain macrophages) soon after status epilepticus has been suggested to be critical for the pathogenesis of mesial temporal lobe epilepsy (MTLE). However, microglial activation in the chronic phase of experimental MTLE has been scarcely addressed. In this study, we questioned whether microglial activation persists in the hippocampus of pilocarpine-treated, epileptic Wistar rats and to which extent it is associated with segmental neurodegeneration. Microglial cells were immunostained for the universal microglial marker, ionized calcium-binding adapter molecule-1 and the activation marker, CD11b (also known as OX42, Mac-1). Using quantitative morphology, i.e., stereology and Neurolucida-based reconstructions, we investigated morphological correlates of microglial activation such as cell number, ramification, somatic size and shape. We find that microglial cells in epileptic rats feature widespread, activation-related morphological changes such as increase in cell number density, massive up-regulation of CD11b and de-ramification. The parameters show heterogeneity in different hippocampal subregions. For instance, de-ramification is most prominent in the outer molecular layer of the dentate gyrus, whereas CD11b expression dominates in hilus. Interestingly, microglial activation only partially correlates with segmental neurodegeneration. Major neuronal death in the hilus, CA3 and CA1 coincides with strong up-regulation of CD11b. However, microglial activation is also observed in subregions that do not feature neurodegeneration, such as the molecular and granular layer of the dentate gyrus. This in vivo study provides solid experimental evidence that microglial cells feature widespread heterogeneous activation that only partially correlates with hippocampal segmental neuronal loss in experimental MTLE.
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Lasarge CL, Danzer SC. Mechanisms regulating neuronal excitability and seizure development following mTOR pathway hyperactivation. Front Mol Neurosci 2014; 7:18. [PMID: 24672426 PMCID: PMC3953715 DOI: 10.3389/fnmol.2014.00018] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 02/27/2014] [Indexed: 01/19/2023] Open
Abstract
The phosphatidylinositol-3-kinase/phosphatase and tensin homolog (PTEN)-mammalian target of rapamycin (mTOR) pathway regulates a variety of neuronal functions, including cell proliferation, survival, growth, and plasticity. Dysregulation of the pathway is implicated in the development of both genetic and acquired epilepsies. Indeed, several causal mutations have been identified in patients with epilepsy, the most prominent of these being mutations in PTEN and tuberous sclerosis complexes 1 and 2 (TSC1, TSC2). These genes act as negative regulators of mTOR signaling, and mutations lead to hyperactivation of the pathway. Animal models deleting PTEN, TSC1, and TSC2 consistently produce epilepsy phenotypes, demonstrating that increased mTOR signaling can provoke neuronal hyperexcitability. Given the broad range of changes induced by altered mTOR signaling, however, the mechanisms underlying seizure development in these animals remain uncertain. In transgenic mice, cell populations with hyperactive mTOR have many structural abnormalities that support recurrent circuit formation, including somatic and dendritic hypertrophy, aberrant basal dendrites, and enlargement of axon tracts. At the functional level, mTOR hyperactivation is commonly, but not always, associated with enhanced synaptic transmission and plasticity. Moreover, these populations of abnormal neurons can affect the larger network, inducing secondary changes that may explain paradoxical findings reported between cell and network functioning in different models or at different developmental time points. Here, we review the animal literature examining the link between mTOR hyperactivation and epileptogenesis, emphasizing the impact of enhanced mTOR signaling on neuronal form and function.
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Affiliation(s)
- Candi L Lasarge
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA
| | - Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA ; Department of Anesthesia, University of Cincinnati Cincinnati, OH, USA ; Department of Pediatrics, University of Cincinnati Cincinnati, OH, USA
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Wong M. A critical review of mTOR inhibitors and epilepsy: from basic science to clinical trials. Expert Rev Neurother 2014; 13:657-69. [PMID: 23739003 DOI: 10.1586/ern.13.48] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Present medications for epilepsy have substantial limitations, such as medical intractability in many patients and lack of antiepileptogenic properties to prevent epilepsy. Drugs with novel mechanisms of action are needed to overcome these limitations. The mTOR signaling pathway has emerged as a possible therapeutic target for epilepsy. Preliminary clinical trials suggest that mTOR inhibitors reduce seizures in tuberous sclerosis complex (TSC) patients with intractable epilepsy. Furthermore, mTOR inhibitors have antiepileptogenic properties in preventing epilepsy in animal models of TSC. Besides TSC, accumulating preclinical data suggest that mTOR inhibitors may have antiseizure or antiepileptogenic actions in other types of epilepsy, including infantile spasms, neonatal hypoxic seizures, absence epilepsy and acquired temporal lobe epilepsy following brain injury, but these effects depend on a number of conditions. Future clinical and basic research is needed to establish whether mTOR inhibitors are an effective treatment for epilepsy.
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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.
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Shang YC, Chong ZZ, Wang S, Maiese K. Wnt1 inducible signaling pathway protein 1 (WISP1) targets PRAS40 to govern β-amyloid apoptotic injury of microglia. Curr Neurovasc Res 2013; 9:239-49. [PMID: 22873724 DOI: 10.2174/156720212803530618] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 07/25/2012] [Accepted: 07/30/2012] [Indexed: 12/21/2022]
Abstract
Given the present challenges to attain effective treatment for β-amyloid (Aβ) toxicity in neurodegenerative disorders such as Alzheimer's disease, development of novel cytoprotective pathways that can assist immune mediated therapies through the preservation of central nervous system microglia could offer significant promise. We show that the CCN4 protein, Wnt1 inducible signaling pathway protein 1 (WISP1), is initially up-regulated by Aβ and can modulate its endogenous expression for the protection of microglia during Aβ mediated apoptosis. WISP1 activates mTOR and phosphorylates p70S6K and 4EBP1 through the control of the regulatory mTOR component PRAS40. Loss of PRAS40 through gene reduction or inhibition by WISP1 is cytoprotective. WISP1 ultimately governs PRAS40 by sequestering PRAS40 intracellularly through post-translational phosphorylation and binding to protein 14-3-3. Our work identifies WISP1, mTOR signaling, and PRAS40 as targets for new strategies directed against Alzheimer's disease and related disorders.
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Affiliation(s)
- Yan Chen Shang
- Laboratory of Cellular and Molecular Signaling, Cancer Center, F 1220, New Jersey Health Sciences University, 205 South Orange Avenue, Newark, NJ 07101, USA
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Roseti C, Fucile S, Lauro C, Martinello K, Bertollini C, Esposito V, Mascia A, Catalano M, Aronica E, Limatola C, Palma E. Fractalkine/CX3CL1 modulates GABAA currents in human temporal lobe epilepsy. Epilepsia 2013; 54:1834-44. [PMID: 24032743 DOI: 10.1111/epi.12354] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2013] [Indexed: 11/30/2022]
Abstract
PURPOSE The chemokine fractalkine/CX3CL1 and its receptor CX3CR1 are widely expressed in the central nervous system (CNS). Recent evidence showed that CX3CL1 participates in inflammatory responses that are common features of CNS disorders, such as epilepsy. Mesial temporal lobe epilepsy (MTLE) is the prevalent form of focal epilepsy in adults, and hippocampal sclerosis (HS) represents the most common underlying pathologic abnormality, as demonstrated at autopsy and postresection studies. Relevant features of MTLE are a characteristic pattern of neuronal loss, as are astrogliosis and microglia activation. Several factors affect epileptogenesis in patients with MTLE, including a lack of γ-aminobutyric acid (GABA)ergic inhibitory efficacy. Therefore, experiments were designed to investigate whether, in MTLE brain tissues, CX3CL1 may influence GABAA receptor (GABAA R) mediated transmission, with a particular focus on the action of CX3CL1 on the use-dependent decrease (rundown) of the GABA-evoked currents (IGABA ), a feature underlying the reduction of GABAergic function in epileptic tissue. METHODS Patch-clamp recordings were obtained from cortical pyramidal neurons in slices from six MTLE patients after surgery. Alternatively, the cell membranes from epileptic brain tissues of 17 MTLE patients or from surgical samples and autopsies of nonepileptic patients were microtransplanted into Xenopus oocytes, and IGABA were recorded using the standard two-microelectrode voltage-clamp technique. Immunohistochemical staining and double-labeling studies were carried out on the same brain tissues to analyze CX3CR1 expression. KEY FINDINGS In native pyramidal neurons from cortical slices of patients with MTLE, CX3CL1 reduced IGABA rundown and affected the recovery of IGABA amplitude from rundown. These same effects were confirmed in oocytes injected with cortical and hippocampal MTLE membranes, whereas CX3CL1 did not influence IGABA in oocytes injected with nonepileptic tissues. Consistent with a specific effect of CX3CL1 on tissues from patients with MTLE, CX3CR1 immunoreactivity was higher in MTLE sclerotic hippocampi than in control tissues, with a prominent expression in activated microglial cells. SIGNIFICANCE These findings indicate a role for CX3CL1 in MTLE, supporting recent evidence on the relevance of brain inflammation in human epilepsies. Our data demonstrate that in MTLE tissues the reduced GABAergic function can be modulated by CX3CL1. The increased CX3CR1 expression in microglia and the modulation by CX3CL1 of GABAergic currents in human epileptic brain suggests new therapeutic approaches for drug-resistant epilepsies based on the evidence that the propagation of seizures can be influenced by inflammatory processes.
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