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Schieweck R, Ninkovic J, Kiebler MA. RNA-binding proteins balance brain function in health and disease. Physiol Rev 2020; 101:1309-1370. [PMID: 33000986 DOI: 10.1152/physrev.00047.2019] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Posttranscriptional gene expression including splicing, RNA transport, translation, and RNA decay provides an important regulatory layer in many if not all molecular pathways. Research in the last decades has positioned RNA-binding proteins (RBPs) right in the center of posttranscriptional gene regulation. Here, we propose interdependent networks of RBPs to regulate complex pathways within the central nervous system (CNS). These are involved in multiple aspects of neuronal development and functioning, including higher cognition. Therefore, it is not sufficient to unravel the individual contribution of a single RBP and its consequences but rather to study and understand the tight interplay between different RBPs. In this review, we summarize recent findings in the field of RBP biology and discuss the complex interplay between different RBPs. Second, we emphasize the underlying dynamics within an RBP network and how this might regulate key processes such as neurogenesis, synaptic transmission, and synaptic plasticity. Importantly, we envision that dysfunction of specific RBPs could lead to perturbation within the RBP network. This would have direct and indirect (compensatory) effects in mRNA binding and translational control leading to global changes in cellular expression programs in general and in synaptic plasticity in particular. Therefore, we focus on RBP dysfunction and how this might cause neuropsychiatric and neurodegenerative disorders. Based on recent findings, we propose that alterations in the entire regulatory RBP network might account for phenotypic dysfunctions observed in complex diseases including neurodegeneration, epilepsy, and autism spectrum disorders.
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Affiliation(s)
- Rico Schieweck
- Biomedical Center (BMC), Department for Cell Biology and Anatomy, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
| | - Jovica Ninkovic
- Biomedical Center (BMC), Department for Cell Biology and Anatomy, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
| | - Michael A Kiebler
- Biomedical Center (BMC), Department for Cell Biology and Anatomy, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
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Clinical Evidence of Antidepressant Effects of Insulin and Anti-Hyperglycemic Agents and Implications for the Pathophysiology of Depression-A Literature Review. Int J Mol Sci 2020; 21:ijms21186969. [PMID: 32971941 PMCID: PMC7554794 DOI: 10.3390/ijms21186969] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/21/2020] [Accepted: 09/15/2020] [Indexed: 02/07/2023] Open
Abstract
Close connections between depression and type 2 diabetes (T2DM) have been suggested by many epidemiological and experimental studies. Disturbances in insulin sensitivity due to the disruption of various molecular pathways cause insulin resistance, which underpins many metabolic disorders, including diabetes, as well as depression. Several anti-hyperglycemic agents have demonstrated antidepressant properties in clinical trials, probably due to their action on brain targets based on the shared pathophysiology of depression and T2DM. In this article, we review reports of clinical trials examining the antidepressant effect of these medications, including insulin, metformin, glucagon like peptide-1 receptor agonists (GLP-1RA), and peroxisome proliferator-activated receptor (PPAR)-γ agonists, and briefly consider possible molecular mechanisms underlying the associations between amelioration of insulin resistance and improvement of depressive symptoms. In doing so, we intend to suggest an integrative perspective for understanding the pathophysiology of depression.
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Kapfhamer D, McKenna J, Yoon CJ, Murray-Stewart T, Casero RA, Gambello MJ. Ornithine decarboxylase, the rate-limiting enzyme of polyamine synthesis, modifies brain pathology in a mouse model of tuberous sclerosis complex. Hum Mol Genet 2020; 29:2395-2407. [PMID: 32588887 PMCID: PMC7424721 DOI: 10.1093/hmg/ddaa121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 05/18/2020] [Accepted: 06/11/2020] [Indexed: 12/11/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a rare autosomal dominant neurodevelopmental disorder characterized by variable expressivity. TSC results from inactivating variants within the TSC1 or TSC2 genes, leading to constitutive activation of mechanistic target of rapamycin complex 1 signaling. Using a mouse model of TSC (Tsc2-RG) in which the Tsc2 gene is deleted in radial glial precursors and their neuronal and glial descendants, we observed increased ornithine decarboxylase (ODC) enzymatic activity and concentration of its product, putrescine. To test if increased ODC activity and dysregulated polyamine metabolism contribute to the neurodevelopmental defects of Tsc2-RG mice, we used pharmacologic and genetic approaches to reduce ODC activity in Tsc2-RG mice, followed by histologic assessment of brain development. We observed that decreasing ODC activity and putrescine levels in Tsc2-RG mice worsened many of the neurodevelopmental phenotypes, including brain growth and neuronal migration defects, astrogliosis and oxidative stress. These data suggest a protective effect of increased ODC activity and elevated putrescine that modify the phenotype in this developmental Tsc2-RG model.
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Affiliation(s)
- David Kapfhamer
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia
| | - James McKenna
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia
| | - Caroline J Yoon
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia
| | - Tracy Murray-Stewart
- The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Robert A Casero
- The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Michael J Gambello
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia
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54
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Feliciano DM. The Neurodevelopmental Pathogenesis of Tuberous Sclerosis Complex (TSC). Front Neuroanat 2020; 14:39. [PMID: 32765227 PMCID: PMC7381175 DOI: 10.3389/fnana.2020.00039] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 06/10/2020] [Indexed: 12/22/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a model disorder for understanding brain development because the genes that cause TSC are known, many downstream molecular pathways have been identified, and the resulting perturbations of cellular events are established. TSC, therefore, provides an intellectual framework to understand the molecular and biochemical pathways that orchestrate normal brain development. The TSC1 and TSC2 genes encode Hamartin and Tuberin which form a GTPase activating protein (GAP) complex. Inactivating mutations in TSC genes (TSC1/TSC2) cause sustained Ras homologue enriched in brain (RHEB) activation of the mammalian isoform of the target of rapamycin complex 1 (mTORC1). TOR is a protein kinase that regulates cell size in many organisms throughout nature. mTORC1 inhibits catabolic processes including autophagy and activates anabolic processes including mRNA translation. mTORC1 regulation is achieved through two main upstream mechanisms. The first mechanism is regulation by growth factor signaling. The second mechanism is regulation by amino acids. Gene mutations that cause too much or too little mTORC1 activity lead to a spectrum of neuroanatomical changes ranging from altered brain size (micro and macrocephaly) to cortical malformations to Type I neoplasias. Because somatic mutations often underlie these changes, the timing, and location of mutation results in focal brain malformations. These mutations, therefore, provide gain-of-function and loss-of-function changes that are a powerful tool to assess the events that have gone awry during development and to determine their functional physiological consequences. Knowledge about the TSC-mTORC1 pathway has allowed scientists to predict which upstream and downstream mutations should cause commensurate neuroanatomical changes. Indeed, many of these predictions have now been clinically validated. A description of clinical imaging and histochemical findings is provided in relation to laboratory models of TSC that will allow the reader to appreciate how human pathology can provide an understanding of the fundamental mechanisms of development.
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Affiliation(s)
- David M Feliciano
- Department of Biological Sciences, Clemson University, Clemson, SC, United States
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55
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Modeling Neurodevelopmental Deficits in Tuberous Sclerosis Complex with Stem Cell Derived Neural Precursors and Neurons. ADVANCES IN NEUROBIOLOGY 2020. [PMID: 32578142 DOI: 10.1007/978-3-030-45493-7_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Tuberous sclerosis complex (TSC) is a rare genetic disorder that is caused by mutations in TSC1 or TSC2. TSC is a multi-organ disorder characterized by development of non-malignant cellular overgrowths, called hamartomas, in different organs of the body. TSC is also characterized as a neurodevelopmental disorder presenting with epilepsy and autism, and formation of cortical malformations ("tubers"), subependymal giant cell astrocytomas (SEGAs), and subependymal nodules (SENs) in the patient's brain. In this chapter, we are going to give an overview of neural stem cell and neuronal development in TSC. In addition, we will also describe previously developed animal models of TSC that display seizures, autistic-like behaviors, and neuronal cell abnormalities in vivo, and we will compare them to disease phenotypes detected with human stem cell derived neuronal cells in vitro. We will describe the effects of TSC-mutations in different neural cell subtypes, and discuss the mitochondrial function, autophagy, and synaptic development and functional deficits in the neurons. Finally, we will review utilization of these human TSC-patient derived neuronal models for drug screening to develop new treatment options for the neurological phenotypes seen in TSC patients.
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56
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Spinelli M, Fusco S, Grassi C. Brain insulin resistance impairs hippocampal plasticity. VITAMINS AND HORMONES 2020; 114:281-306. [PMID: 32723548 DOI: 10.1016/bs.vh.2020.04.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nutrient-related signals have been demonstrated to influence brain development and cognitive functions. In particular, insulin signaling has been shown to impact on molecular cascades underlying hippocampal plasticity, learning and memory. Alteration of brain insulin signaling interferes with the maintenance of neural stem cell niche and neuronal activity in the hippocampus. Brain insulin resistance is also emerging as key factor causing the cognitive impairment observed in metabolic and neurodegenerative diseases. Here, we review the molecular mechanisms involved in the insulin modulation of both adult neurogenesis and synaptic activity in the hippocampus. We also summarize the effects of altered insulin sensitivity on hippocampal plasticity. Finally, we reassume the experimental and epidemiological evidence highlighting the critical role of brain insulin resistance at the crossroad between type 2 diabetes and Alzheimer's disease.
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Affiliation(s)
- Matteo Spinelli
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Salvatore Fusco
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.
| | - Claudio Grassi
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.
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Su Y, Zhang W, Patro CPK, Zhao J, Mu T, Ma Z, Xu J, Ban K, Yi C, Zhou Y. STAT3 Regulates Mouse Neural Progenitor Proliferation and Differentiation by Promoting Mitochondrial Metabolism. Front Cell Dev Biol 2020; 8:362. [PMID: 32509786 PMCID: PMC7248371 DOI: 10.3389/fcell.2020.00362] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 04/22/2020] [Indexed: 02/05/2023] Open
Abstract
The proliferation and differentiation of neural progenitor lay the foundation for brain development. In neural progenitors, activation of Signal Transducer and Activator of Transcription 3 (STAT3) has been found to promote proliferation and astrocytogenesis while suppressing neurogenesis. However, our study found that Stat3 conditional knockout in neural progenitors (Stat3 cKO) also results in increased proliferation and suppressed neurogenesis. To investigate how STAT3 regulates these processes, we attempted to identify potential STAT3 target genes by RNA-seq profiling of the control (CTL) and Stat3 cKO neural progenitors. We found that STAT3 promotes the expression of genes involved in the mitochondrial oxidative phosphorylation (OXPHOS), and thereby promotes mitochondrial respiration and negatively regulates reactive oxygen species (ROS) production. In addition, we demonstrated that Stat3 loss-of-function promotes proliferation via regulation of mitochondrial metabolism and downstream signaling pathways. Our study provides novel insights into the relation between STAT3, mitochondrial metabolism and the process of embryonic neurogenesis.
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Affiliation(s)
- Yixun Su
- The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Neurobiology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Wenjun Zhang
- School of Medicine, Indiana University, Indianapolis, IN, United States
| | - C Pawan K Patro
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Cancer Science Institute of Singapore, Singapore, Singapore
| | - Jing Zhao
- Neurobiology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Tianhao Mu
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Cancer Science Institute of Singapore, Singapore, Singapore
| | - Zhongnan Ma
- Department of Biology, Southern University of Science and Technology, Shenzhen, China.,West China Hospital, Sichuan University, Chengdu, China.,Model Animal Research Center of Nanjing University, Nanjing, China
| | - Jianqiang Xu
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Kenneth Ban
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Chenju Yi
- The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Yi Zhou
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Neurobiology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore.,West China Hospital, Sichuan University, Chengdu, China
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58
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Complete neural stem cell (NSC) neuronal differentiation requires a branched chain amino acids-induced persistent metabolic shift towards energy metabolism. Pharmacol Res 2020; 158:104863. [PMID: 32407957 DOI: 10.1016/j.phrs.2020.104863] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/08/2020] [Accepted: 04/24/2020] [Indexed: 02/08/2023]
Abstract
Neural stem cell (NSC) neuronal differentiation requires a metabolic shift towards oxidative phosphorylation. We now show that a branched-chain amino acids-driven, persistent metabolic shift toward energy metabolism is required for full neuronal maturation. We increased energy metabolism of differentiating neurons derived both from murine NSCs and human induced pluripotent stem cells (iPSCs) by supplementing the cell culture medium with a mixture composed of branched-chain amino acids, essential amino acids, TCA cycle precursors and co-factors. We found that treated differentiating neuronal cells with enhanced energy metabolism increased: i) total dendritic length; ii) the mean number of branches and iii) the number and maturation of the dendritic spines. Furthermore, neuronal spines in treated neurons appeared more stable with stubby and mushroom phenotype and with increased expression of molecules involved in synapse formation. Treated neurons modified their mitochondrial dynamics increasing the mitochondrial fusion and, consistently with the increase of cellular ATP content, they activated cellular mTORC1 dependent p70S6 K1 anabolism. Global transcriptomic analysis further revealed that treated neurons induce Nrf2 mediated gene expression. This was correlated with a functional increase in the Reactive Oxygen Species (ROS) scavenging mechanisms. In conclusion, persistent branched-chain amino acids-driven metabolic shift toward energy metabolism enhanced neuronal differentiation and antioxidant defences. These findings offer new opportunities to pharmacologically modulate NSC neuronal differentiation and to develop effective strategies for treating neurodegenerative diseases.
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59
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Kumari K, Sharma MC, Kakkar A, Malgulwar PB, Pathak P, Suri V, Sarkar C, Chandra SP, Faruq M. mTOR pathway activation in focal cortical dysplasia. Ann Diagn Pathol 2020; 46:151523. [PMID: 32325422 DOI: 10.1016/j.anndiagpath.2020.151523] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 02/21/2020] [Accepted: 03/24/2020] [Indexed: 01/05/2023]
Abstract
BACKGROUND Focal cortical dysplasia (FCD) is a localized cortical malformation and considerable morphological overlap exists between FCD IIB and neurological lesions associated with Tuberous sclerosis complex (TSC). Abnormal mTOR pathway secondary to somatic mTOR mutation and TSC gene mutation linked to PI3K/AKT/mTOR pathway have supported the hypothesis of common pathogenesis involved. Role of converging pathway, viz. Wnt/β-Catenin and mTOR is unknown in FCD. We aimed to analyse FCD IIB for TSC1/TSC2 mutations, immunoreactivity of hamartin, tuberin, mTOR and Wnt signalling cascades, and stem cell markers. MATERIALS AND METHODS Sixteen FCD IIB cases were retrieved along with 16 FCD IIA cases for comparison. Immunohistochemistry was performed for tuberin, hamartin, mTOR pathway markers, markers of stem cell phenotype, and Wnt pathway markers. Mutation analysis for TSC1 and TSC2 was performed by sequencing in 9 FCD cases. RESULTS All FCD cases showed preserved hamartin and tuberin immunoreactivity. Aberrant immunoreactivity of phospho-P70S6 kinase, S6 ribosomal, phospho-S6 ribosomal and Stat3 was noted in FCD IIB, with variable phospho-4E-BP1 (45%) and absent phospho-Stat3 expression. Immunoreactivity for phospho-P70S6 kinase (100%), S6 ribosomal protein (100%) and Stat3 (100%) was noted in FCD IIA, but not for phospho-S6 ribosomal, phospho-4E-BP1 and phospho-Stat3. c-Myc immunoreactivity was noted in all FCD cases. Nestin (81%) and Sox 2 (88%) stained balloon cells in FCD IIB (44%), while in FCD IIA cases were negative. All FCD cases were immunopositive for Wnt, but were negative for β-Catenin and cyclin-D1. TSC mutations were detected in two cases of FCD IIB. CONCLUSION Abnormal mTOR pathway activation exists in FCD IIB and IIA, however, shows differential immunoreactivity profile, indicating varying degrees of dysregulation. Labelling of neuronal stem cell markers in balloon cells suggests they are phenotypically immature. TSC1/2 mutation play role in the pathogenesis of FCD. Deep targeted sequencing is preferred diagnostic technique since conventional sanger sequencing often fails to detect low-allele frequency variants involved in mTOR/TSC pathway genes, commonly found in FCD.
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Affiliation(s)
- Kalpana Kumari
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Mehar C Sharma
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India.
| | - Aanchal Kakkar
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Prit B Malgulwar
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Pankaj Pathak
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Vaishali Suri
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Chitra Sarkar
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Sarat P Chandra
- Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India
| | - Mohammed Faruq
- Institute of Genomics and Integrative Biology - Council of Scientific and Industrial Research, New Delhi, India
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60
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Rensing N, Johnson KJ, Foutz TJ, Friedman JL, Galindo R, Wong M. Early developmental electroencephalography abnormalities, neonatal seizures, and induced spasms in a mouse model of tuberous sclerosis complex. Epilepsia 2020; 61:879-891. [PMID: 32274803 DOI: 10.1111/epi.16495] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Tuberous sclerosis complex (TSC) is one of the most common genetic causes of epilepsy. Seizures in TSC typically first present in infancy or early childhood, including focal seizures and infantile spasms. Infantile spasms in TSC are particularly characteristic in its strong responsiveness to vigabatrin. Although a number of mouse models of epilepsy in TSC have been described, there are very limited electroencephalographic (EEG) or seizure data during the preweanling neonatal and infantile-equivalent mouse periods. Tsc1GFAP CKO mice are a well-characterized mouse model of epilepsy in TSC, but whether these mice have seizures during early development has not been documented. The objective of this study was to determine whether preweanling Tsc1GFAP CKO mice have developmental EEG abnormalities or seizures, including spasms. METHODS Longitudinal video-EEG and electromyographic recordings were performed serially on Tsc1GFAP CKO and control mice from postnatal days 9-21 and analyzed for EEG background abnormalities, sleep-wake vigilance states, and spontaneous seizures. Spasms were also induced with varying doses of N-methyl-D-aspartate (NMDA). RESULTS The interictal EEG of Tsc1GFAP CKO mice had excessive discontinuity and slowing, suggesting a delayed developmental progression compared with control mice. Tsc1GFAP CKO mice also had increased vigilance state transitions and fragmentation. Tsc1GFAP CKO mice had spontaneous focal seizures in the early neonatal period and a reduced threshold for NMDA-induced spasms, but no spontaneous spasms were observed. SIGNIFICANCE Neonatal Tsc1GFAP CKO mice recapitulate early developmental aspects of EEG abnormalities, focal seizures, and an increased propensity for spasms. This mouse model may be useful for early mechanistic and therapeutic studies of epileptogenesis in TSC.
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Affiliation(s)
- Nicholas Rensing
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, Missouri
| | - Kevin J Johnson
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, Missouri
| | - Thomas J Foutz
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, Missouri
| | - Joseph L Friedman
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, Missouri
| | - Rafael Galindo
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, Missouri
| | - Michael Wong
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, Missouri
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Tarkowski B, Kuchcinska K, Blazejczyk M, Jaworski J. Pathological mTOR mutations impact cortical development. Hum Mol Genet 2020; 28:2107-2119. [PMID: 30789219 DOI: 10.1093/hmg/ddz042] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/08/2019] [Accepted: 02/11/2019] [Indexed: 02/03/2023] Open
Abstract
Several mosaic mutations of the mammalian/mechanistic target of rapamycin (mTOR) have recently been found in patients with cortical malformations, such as hemimegalencephaly (HME) and focal cortical dysplasia (FCD). Although all of them should activate mTOR signaling, comparisons of the impact of different mTOR mutations on brain development have been lacking. Also it remains unknown if any potential differences these mutations may have on cortical development are directly related to a degree of mTOR signaling increase. The present study assessed levels of mTORC1 pathway activity in cell lines and rat primary neurons overexpressing several mTOR mutants that were previously found in HME, FCD, cancer patients and in vitro mutagenesis screens. Next we introduced the mutants, enhancing mTORC1 signaling most potently, into developing mouse brains and assessed electroporated cell morphology and migratory phenotype using immunofluorescent staining. We observed the differential inhibition of neuronal progenitor cortical migration, which partly corresponded with a degree of mTORC1 signaling enhancement these mutants induced in cultured cells. The most potent quadruple mutant prevented most of the progenitors from entering the cortical plate. Cells that expressed less potent, single-point, mTOR mutants entered the cortical plate but failed to reach its upper layers and had enlarged soma. Our findings suggest a correlation between the potency of mTOR mutation to activate mTORC1 pathway and disruption of cortical migration.
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Affiliation(s)
- Bartosz Tarkowski
- International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Kinga Kuchcinska
- International Institute of Molecular and Cell Biology, Warsaw, Poland
| | | | - Jacek Jaworski
- International Institute of Molecular and Cell Biology, Warsaw, Poland
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62
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Madsen RR. PI3K in stemness regulation: from development to cancer. Biochem Soc Trans 2020; 48:301-315. [PMID: 32010943 PMCID: PMC7054754 DOI: 10.1042/bst20190778] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 01/04/2020] [Accepted: 01/07/2020] [Indexed: 02/08/2023]
Abstract
The PI3K/AKT pathway is a key target in oncology where most efforts are focussed on phenotypes such as cell proliferation and survival. Comparatively, little attention has been paid to PI3K in stemness regulation, despite the emerging link between acquisition of stem cell-like features and therapeutic failure in cancer. The aim of this review is to summarise current known and unknowns of PI3K-dependent stemness regulation, by integrating knowledge from the fields of developmental, signalling and cancer biology. Particular attention is given to the role of the PI3K pathway in pluripotent stem cells (PSCs) and the emerging parallels to dedifferentiated cancer cells with stem cell-like features. Compelling evidence suggests that PI3K/AKT signalling forms part of a 'core molecular stemness programme' in both mouse and human PSCs. In cancer, the oncogenic PIK3CAH1047R variant causes constitutive activation of the PI3K pathway and has recently been linked to increased stemness in a dose-dependent manner, similar to observations in mouse PSCs with heterozygous versus homozygous Pten loss. There is also evidence that the stemness phenotype may become 'locked' and thus independent of the original PI3K activation, posing limitations for the success of PI3K monotherapy in cancer. Ongoing therapeutic developments for PI3K-associated cancers may therefore benefit from a better understanding of the pathway's two-layered and highly context-dependent regulation of cell growth versus stemness.
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Affiliation(s)
- Ralitsa R. Madsen
- UCL Cancer Institute, Paul O'Gorman Building, University College London, 72 Huntley Street, London WC1E 6DD, U.K
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63
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The Ubiquitin System: a Regulatory Hub for Intellectual Disability and Autism Spectrum Disorder. Mol Neurobiol 2020; 57:2179-2193. [DOI: 10.1007/s12035-020-01881-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 01/15/2020] [Indexed: 12/15/2022]
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64
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TrkB hyperactivity contributes to brain dysconnectivity, epileptogenesis, and anxiety in zebrafish model of Tuberous Sclerosis Complex. Proc Natl Acad Sci U S A 2020; 117:2170-2179. [PMID: 31932427 PMCID: PMC6995026 DOI: 10.1073/pnas.1910834117] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Tuberous Sclerosis Complex (TSC) is a rare genetic disease that manifests with early symptoms, including cortical malformations, childhood epilepsy, and TSC-associated neuropsychiatric disorders (TANDs). Cortical malformations arise during embryonic development and have been linked to childhood epilepsy before, but the underlying mechanisms of this relationship remain insufficiently understood. Zebrafish have emerged as a convenient model to study elementary neurodevelopment; however, without in-depth functional analysis, the Tsc2-deficient zebrafish line cannot be used for studies of TANDs or new drug screening. In this study, we found that the lack of Tsc2 in zebrafish resulted in heterotopias and hyperactivation of the mTorC1 pathway in pallial regions, which are homologous to the mammalian cortex. We observed commissural thinning that was responsible for brain dysconnectivity, recapitulating TSC pathology in human patients. The lack of Tsc2 also delayed axonal development and caused aberrant tract fasciculation, corresponding to the abnormal expression of genes involved in axon navigation. The mutants underwent epileptogenesis that resulted in nonmotor seizures and exhibited increased anxiety-like behavior. We further mapped discrete parameters of locomotor activity to epilepsy-like and anxiety-like behaviors, which were rescued by reducing tyrosine receptor kinase B (TrkB) signaling. Moreover, in contrast to treatment with vigabatrin and rapamycin, TrkB inhibition rescued brain dysconnectivity and anxiety-like behavior. These data reveal that commissural thinning results in the aberrant regulation of anxiety, providing a mechanistic link between brain anatomy and human TANDs. Our findings also implicate TrkB signaling in the complex pathology of TSC and reveal a therapeutic target.
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Wang C, Haas MA, Yang F, Yeo S, Okamoto T, Chen S, Wen J, Sarma P, Plas DR, Guan JL. Autophagic lipid metabolism sustains mTORC1 activity in TSC-deficient neural stem cells. Nat Metab 2019; 1:1127-1140. [PMID: 32577608 PMCID: PMC7311104 DOI: 10.1038/s42255-019-0137-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Although mTORC1 negatively regulates autophagy in cultured cells, how autophagy impacts mTORC1 signaling, in particular in vivo, is less clear. Here we show that autophagy supports mTORC1 hyperactivation in NSCs lacking Tsc1, thereby promoting defects in NSC maintenance, differentiation, tumourigenesis, and the formation of the neurodevelopmental lesion of Tuberous Sclerosis Complex (TSC). Analysing mice that lack Tsc1 and the essential autophagy gene Fip200 in NSCs we find that TSC-deficient cells require autophagy to maintain mTORC1 hyperactivation under energy stress conditions, likely to provide lipids via lipophagy to serve as an alternative energy source for OXPHOS. In vivo, inhibition of lipophagy or its downstream catabolic pathway reverses defective phenotypes caused by Tsc1-null NSCs and reduces tumorigenesis in mouse models. These results reveal a cooperative function of selective autophagy in coupling energy availability with TSC pathogenesis and suggest a potential new therapeutic strategy to treat TSC patients.
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Affiliation(s)
- Chenran Wang
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
| | - Michael A Haas
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Fuchun Yang
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Syn Yeo
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Takako Okamoto
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Song Chen
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Jian Wen
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- Department of Breast Surgery, Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Pranjal Sarma
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - David R Plas
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Jun-Lin Guan
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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66
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Dawson RE, Nieto Guil AF, Robertson LJ, Piltz SG, Hughes JN, Thomas PQ. Functional screening of GATOR1 complex variants reveals a role for mTORC1 deregulation in FCD and focal epilepsy. Neurobiol Dis 2019; 134:104640. [PMID: 31639411 DOI: 10.1016/j.nbd.2019.104640] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 10/07/2019] [Accepted: 10/13/2019] [Indexed: 12/20/2022] Open
Abstract
Mutations in the GAP activity toward RAGs 1 (GATOR1) complex genes (DEPDC5, NPRL2 and NPRL3) have been associated with focal epilepsy and focal cortical dysplasia (FCD). GATOR1 functions as an inhibitor of the mTORC1 signalling pathway, indicating that the downstream effects of mTORC1 deregulation underpin the disease. However, the vast majority of putative disease-causing variants have not been functionally assessed for mTORC1 repression activity. Here, we develop a novel in vitro functional assay that enables rapid assessment of GATOR1-gene variants. Surprisingly, of the 17 variants tested, we show that only six showed significantly impaired mTORC1 inhibition. To further investigate variant function in vivo, we generated a conditional Depdc5 mouse which modelled a 'second-hit' mechanism of disease. Generation of Depdc5 null 'clones' in the embryonic brain resulted in mTORC1 hyperactivity and modelled epilepsy and FCD symptoms including large dysmorphic neurons, defective migration and lower seizure thresholds. Using this model, we validated DEPDC5 variant F164del to be loss-of-function. We also show that Q542P is not functionally compromised in vivo, consistent with our in vitro findings. Overall, our data show that mTORC1 deregulation is the central pathological mechanism for GATOR1 variants and also indicates that a significant proportion of putative disease variants are pathologically inert, highlighting the importance of GATOR1 variant functional assessment.
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Affiliation(s)
- Ruby E Dawson
- School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia; Robinson Research Institute, University of Adelaide, Adelaide, SA 5005, Australia.
| | - Alvaro F Nieto Guil
- School of Medicine, University of Adelaide, Adelaide, SA 5005, Australia; Robinson Research Institute, University of Adelaide, Adelaide, SA 5005, Australia.
| | - Louise J Robertson
- School of Medicine, University of Adelaide, Adelaide, SA 5005, Australia; Robinson Research Institute, University of Adelaide, Adelaide, SA 5005, Australia.
| | - Sandra G Piltz
- School of Medicine, University of Adelaide, Adelaide, SA 5005, Australia; Robinson Research Institute, University of Adelaide, Adelaide, SA 5005, Australia.
| | - James N Hughes
- School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia; Robinson Research Institute, University of Adelaide, Adelaide, SA 5005, Australia.
| | - Paul Q Thomas
- School of Medicine, University of Adelaide, Adelaide, SA 5005, Australia; Robinson Research Institute, University of Adelaide, Adelaide, SA 5005, Australia; Precision Medicine Theme, South Australia Health and Medical Research Institute, Adelaide, SA 5000, Australia.
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67
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Fukui M, Katayama S, Ikeya Y, Inazu T. Yokukansan, a Kampo medicine, enhances the level of neuronal lineage markers in differentiated P19 embryonic carcinoma cells. Heliyon 2019; 5:e02662. [PMID: 31692643 PMCID: PMC6806406 DOI: 10.1016/j.heliyon.2019.e02662] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 09/11/2019] [Accepted: 10/11/2019] [Indexed: 02/01/2023] Open
Abstract
Yokukansan (YKS), a traditional Japanese Kampo medicine, affects neurological and psychiatric disorders. It ameliorates hippocampal neurogenesis in animals. However, its effect on neuronal cell differentiation remains unclear. Therefore, we investigated the effects of YKS on pluripotent P19 embryonic carcinoma cells as neuronal differentiation model cells. Western blotting and immunocytochemistry revealed that 10 μg/mL YKS treatment during embryoid body formation or neuronal differentiation increased the expression of the neuronal stem cell marker, Nestin, by 1.9-fold and 1.7-fold, respectively, and of the mature neuron marker, NeuN, by 1.5-fold and 1.4-fold, respectively. We examined the effect of YKS on intracellular signaling pathways in P19 cells and found significant elevation in phospho-PDK1 and phospho-mTOR expression (1.1-fold and 1.2-fold, respectively). Therefore, we investigated the effect of PDK1 and mTOR inhibitors on the level of neuronal lineage markers. We found that the mTOR inhibitor significantly abolished the YKS effect on the level of neuronal lineage markers. Moreover, to identify the target(s) of YKS, antibody array analysis that simultaneously detects 16 phosphorylated proteins was performed. YKS significantly upregulated 10 phosphorylated proteins including PDK1, Akt, AMPK, PRAS40, mTOR, p70 S6 kinase, GSK-3α, Bad and ERK1/2 under cell proliferation conditions. These results suggest that YKS simultaneously activates multiple signaling pathways. Thus, we concluded that YKS enhances the level of neuronal lineage markers in differentiated P19 cells, however it does not induce neuronal differentiation. Furthermore, mTOR is the predominant mediator of the YKS effect on these cells.
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Affiliation(s)
- Makoto Fukui
- Department of Pharmacy, College of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Syouichi Katayama
- Department of Pharmacy, College of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Yukinobu Ikeya
- Center for Supporting Pharmaceutical Education, Daiichi University of Pharmacy, Minami, Fukuoka, 815-8511, Japan
| | - Tetsuya Inazu
- Department of Pharmacy, College of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
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68
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Ryskalin L, Gaglione A, Limanaqi F, Biagioni F, Familiari P, Frati A, Esposito V, Fornai F. The Autophagy Status of Cancer Stem Cells in Gliobastoma Multiforme: From Cancer Promotion to Therapeutic Strategies. Int J Mol Sci 2019; 20:ijms20153824. [PMID: 31387280 PMCID: PMC6695733 DOI: 10.3390/ijms20153824] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 07/26/2019] [Accepted: 08/03/2019] [Indexed: 02/07/2023] Open
Abstract
Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor featuring rapid cell proliferation, treatment resistance, and tumor relapse. This is largely due to the coexistence of heterogeneous tumor cell populations with different grades of differentiation, and in particular, to a small subset of tumor cells displaying stem cell-like properties. This is the case of glioma stem cells (GSCs), which possess a powerful self-renewal capacity, low differentiation, along with radio- and chemo-resistance. Molecular pathways that contribute to GBM stemness of GSCs include mTOR, Notch, Hedgehog, and Wnt/β-catenin. Remarkably, among the common biochemical effects that arise from alterations in these pathways, autophagy suppression may be key in promoting GSCs self-renewal, proliferation, and pluripotency maintenance. In fact, besides being a well-known downstream event of mTOR hyper-activation, autophagy downregulation is also bound to the effects of aberrantly activated Notch, Hedgehog, and Wnt/β-catenin pathways in GBM. As a major orchestrator of protein degradation and turnover, autophagy modulates proliferation and differentiation of normal neuronal stem cells (NSCs) as well as NSCs niche maintenance, while its failure may contribute to GSCs expansion and maintenance. Thus, in the present review we discuss the role of autophagy in GSCs metabolism and phenotype in relationship with dysregulations of a variety of NSCs controlling pathways, which may provide novel insights into GBM neurobiology.
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Affiliation(s)
- Larisa Ryskalin
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, via Roma 55, 56126, Pisa, Italy
| | | | - Fiona Limanaqi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, via Roma 55, 56126, Pisa, Italy
| | | | | | - Alessandro Frati
- I.R.C.C.S. Neuromed, via Atinense 18, 86077 Pozzilli (IS), Italy
| | - Vincenzo Esposito
- I.R.C.C.S. Neuromed, via Atinense 18, 86077 Pozzilli (IS), Italy
- Sapienza University of Rome, 00185 Roma, Italy
| | - Francesco Fornai
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, via Roma 55, 56126, Pisa, Italy.
- I.R.C.C.S. Neuromed, via Atinense 18, 86077 Pozzilli (IS), Italy.
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69
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Spinelli M, Fusco S, Grassi C. Brain Insulin Resistance and Hippocampal Plasticity: Mechanisms and Biomarkers of Cognitive Decline. Front Neurosci 2019; 13:788. [PMID: 31417349 PMCID: PMC6685093 DOI: 10.3389/fnins.2019.00788] [Citation(s) in RCA: 134] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 07/15/2019] [Indexed: 12/27/2022] Open
Abstract
In the last decade, much attention has been devoted to the effects of nutrient-related signals on brain development and cognitive functions. A turning point was the discovery that brain areas other than the hypothalamus expressed receptors for hormones related to metabolism. In particular, insulin signaling has been demonstrated to impact on molecular cascades underlying hippocampal plasticity, learning and memory. Here, we summarize the molecular evidence linking alteration of hippocampal insulin sensitivity with changes of both adult neurogenesis and synaptic plasticity. We also review the epidemiological studies and experimental models emphasizing the critical role of brain insulin resistance at the crossroad between metabolic and neurodegenerative disease. Finally, we brief novel findings suggesting how biomarkers of brain insulin resistance, involving the study of brain-derived extracellular vesicles and brain glucose metabolism, may predict the onset and/or the progression of cognitive decline.
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Affiliation(s)
- Matteo Spinelli
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Salvatore Fusco
- Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
| | - Claudio Grassi
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy.,Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
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70
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Koene LMC, van Grondelle SE, Proietti Onori M, Wallaard I, Kooijman NHRM, van Oort A, Schreiber J, Elgersma Y. Effects of antiepileptic drugs in a new TSC/mTOR-dependent epilepsy mouse model. Ann Clin Transl Neurol 2019; 6:1273-1291. [PMID: 31353861 PMCID: PMC6649373 DOI: 10.1002/acn3.50829] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 06/05/2019] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE An epilepsy mouse model for Tuberous Sclerosis Complex (TSC) was developed and validated to investigate the mechanisms underlying epileptogenesis. Furthermore, the possible antiepileptogenic properties of commonly used antiepileptic drugs (AEDs) and new compounds were assessed. METHODS Tsc1 deletion was induced in CAMK2A-expressing neurons of adult mice. The antiepileptogenic properties of commonly used AEDs and inhibitors of the mTOR pathways were assessed by EEG recordings and by molecular read outs. RESULTS Mice developed epilepsy in a narrow time window (10 ± 2 days) upon Tsc1 gene deletion. Seizure frequency but not duration increased over time. Seizures were lethal within 18 days, were unpredictable, and did not correlate to seizure onset, length or frequency, reminiscent of sudden unexpected death in epilepsy (SUDEP). Tsc1 gene deletion resulted in a strong activation of the mTORC1 pathway, and both epileptogenesis and lethality could be entirely prevented by RHEB1 gene deletion or rapamycin treatment. However, other inhibitors of the mTOR pathway such as AZD8055 and PF4708671 were ineffective. Except for ketogenic diet, none of commonly used AEDs showed an effect on mTORC1 activity. Vigabatrin and ketogenic diet treatment were able to significantly delay seizure onset. In contrast, survival was shortened by lamotrigine. INTERPRETATION This novel Tsc1 mouse model is highly suitable to assess the efficacy of antiepileptic and -epileptogenic drugs to treat mTORC1-dependent epilepsy. Additionally, it allows us to study the mechanisms underlying mTORC1-mediated epileptogenesis and SUDEP. We found that early treatment with vigabatrin was not able to prevent epilepsy, but significantly delayed seizure onset.
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Affiliation(s)
- Linda M C Koene
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC University Medical Center, Rotterdam, 3015 CN, The Netherlands
| | - Saskia E van Grondelle
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC University Medical Center, Rotterdam, 3015 CN, The Netherlands
| | - Martina Proietti Onori
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC University Medical Center, Rotterdam, 3015 CN, The Netherlands
| | - Ilse Wallaard
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC University Medical Center, Rotterdam, 3015 CN, The Netherlands
| | - Nathalie H R M Kooijman
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC University Medical Center, Rotterdam, 3015 CN, The Netherlands
| | - Annabel van Oort
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC University Medical Center, Rotterdam, 3015 CN, The Netherlands
| | - Jadwiga Schreiber
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC University Medical Center, Rotterdam, 3015 CN, The Netherlands
| | - Ype Elgersma
- Department of Neuroscience and ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC University Medical Center, Rotterdam, 3015 CN, The Netherlands
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71
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Zhang L, Huang T, Teaw S, Bordey A. Hypervascularization in mTOR-dependent focal and global cortical malformations displays differential rapamycin sensitivity. Epilepsia 2019; 60:1255-1265. [PMID: 31125447 DOI: 10.1111/epi.15969] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 04/26/2019] [Accepted: 04/26/2019] [Indexed: 01/16/2023]
Abstract
OBJECTIVES Patients with mammalian target of rapamycin (mTOR)-dependent malformations of cortical development (MCDs) associated with seizures display hyperperfusion and increased vessel density of the dysmorphic cortical tissue. Some studies have suggested that the vascular defect occurred independently of seizures. Here, we further examined whether hypervascularization occurs in animal models of global and focal MCD with and without seizures, and whether it is sensitive to the mTOR blocker, rapamycin, that is approved for epilepsy treatment in tuberous sclerosis complex. METHODS We used two experimental models of mTOR-dependent MCD consisting of conditional transgenic mice containing Tsc1null cells in the forebrain generating a global malformation associated with seizures and of wild-type mice containing a focal malformation in the somatosensory cortex generated by in utero electroporation (IUE) that does not lead to seizures. Alterations in blood vessels and the effects of a 2-week-long rapamycin treatment on these phenotypes were assessed in juvenile mice. RESULTS Blood vessels in both the focal and global MCDs of postnatal day 14 mice displayed significant increase in vessel density, branching index, total vessel length, and decreased tissue lacunarity. In addition, rapamycin treatment (0.5 mg/kg, every 2 days) partially rescued vessel abnormalities in the focal MCD model, but it did not ameliorate the vessel abnormalities in the global MCD model that required higher rapamycin dosage for a partial rescue. SIGNIFICANCE Here, we identified hypervascularization in mTOR-dependent MCD in the absence of seizures in young mice, suggesting that increased angiogenesis occurs during development in parallel to alterations in corticogenesis. In addition, a predictive functional outcome is that dysplastic neurons forming MCD will have better access to oxygen and metabolic supplies via their closer proximity to blood vessels. Finally, the difference in rapamycin sensitivity between a focal and global MCD suggest that rapamycin treatment will need to be titrated to match the type of MCD.
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Affiliation(s)
- Longbo Zhang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Departments of Neurosurgery and Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
| | - Tianxiang Huang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Departments of Neurosurgery and Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
| | - Shannon Teaw
- Departments of Neurosurgery and Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
| | - Angélique Bordey
- Departments of Neurosurgery and Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
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Salussolia CL, Klonowska K, Kwiatkowski DJ, Sahin M. Genetic Etiologies, Diagnosis, and Treatment of Tuberous Sclerosis Complex. Annu Rev Genomics Hum Genet 2019; 20:217-240. [PMID: 31018109 DOI: 10.1146/annurev-genom-083118-015354] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that affects multiple organ systems due to an inactivating variant in either TSC1 or TSC2, resulting in the hyperactivation of the mechanistic target of rapamycin (mTOR) pathway. Dysregulated mTOR signaling results in increased cell growth and proliferation. Clinically, TSC patients exhibit great phenotypic variability, but the neurologic and neuropsychiatric manifestations of the disease have the greatest morbidity and mortality. TSC-associated epilepsy occurs in nearly all patients and is often difficult to treat because it is refractory to multiple antiseizure medications. The advent of mTOR inhibitors offers great promise in the treatment of TSC-associated epilepsy and other neurodevelopmental manifestations of the disease; however, the optimal timing of therapeutic intervention is not yet fully understood.
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Affiliation(s)
- Catherine L Salussolia
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA;
| | - Katarzyna Klonowska
- Division of Pulmonary and Critical Care Medicine and Division of Genetics, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - David J Kwiatkowski
- Division of Pulmonary and Critical Care Medicine and Division of Genetics, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Mustafa Sahin
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA;
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Karakatsani A, Shah B, Ruiz de Almodovar C. Blood Vessels as Regulators of Neural Stem Cell Properties. Front Mol Neurosci 2019; 12:85. [PMID: 31031591 PMCID: PMC6473036 DOI: 10.3389/fnmol.2019.00085] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 03/20/2019] [Indexed: 01/07/2023] Open
Abstract
In the central nervous system (CNS), a precise communication between the vascular and neural compartments is essential for proper development and function. Recent studies demonstrate that certain neuronal populations secrete various molecular cues to regulate blood vessel growth and patterning in the spinal cord and brain during development. Interestingly, the vasculature is now emerging as a critical component that regulates stem cell niches during neocortical development, as well as during adulthood. In this review article, we will first provide an overview of blood vessel development and maintenance in embryonic and adult neurogenic niches. We will also summarize the current understanding of how blood vessel-derived signals influence the behavior of neural stem cells (NSCs) during early development as well as in adulthood, with a focus on their metabolism.
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Affiliation(s)
- Andromachi Karakatsani
- European Center for Angioscience, Medicine Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Bhavin Shah
- European Center for Angioscience, Medicine Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Carmen Ruiz de Almodovar
- European Center for Angioscience, Medicine Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Institute for Transfusion Medicine and Immunology, Medicine Faculty Mannheim, Heidelberg University, Mannheim, Germany
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74
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Loss of postnatal quiescence of neural stem cells through mTOR activation upon genetic removal of cysteine string protein-α. Proc Natl Acad Sci U S A 2019; 116:8000-8009. [PMID: 30926666 DOI: 10.1073/pnas.1817183116] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Neural stem cells continuously generate newborn neurons that integrate into and modify neural circuitry in the adult hippocampus. The molecular mechanisms that regulate or perturb neural stem cell proliferation and differentiation, however, remain poorly understood. Here, we have found that mouse hippocampal radial glia-like (RGL) neural stem cells express the synaptic cochaperone cysteine string protein-α (CSP-α). Remarkably, in CSP-α knockout mice, RGL stem cells lose quiescence postnatally and enter into a high-proliferation regime that increases the production of neural intermediate progenitor cells, thereby exhausting the hippocampal neural stem cell pool. In cell culture, stem cells in hippocampal neurospheres display alterations in proliferation for which hyperactivation of the mechanistic target of rapamycin (mTOR) signaling pathway is the primary cause of neurogenesis deregulation in the absence of CSP-α. In addition, RGL cells lose quiescence upon specific conditional targeting of CSP-α in adult neural stem cells. Our findings demonstrate an unanticipated cell-autonomic and circuit-independent disruption of postnatal neurogenesis in the absence of CSP-α and highlight a direct or indirect CSP-α/mTOR signaling interaction that may underlie molecular mechanisms of brain dysfunction and neurodegeneration.
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75
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Hyperactivation of mTORC1 disrupts cellular homeostasis in cerebellar Purkinje cells. Sci Rep 2019; 9:2799. [PMID: 30808980 PMCID: PMC6391425 DOI: 10.1038/s41598-019-38730-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 11/19/2018] [Indexed: 11/08/2022] Open
Abstract
Mammalian target of rapamycin (mTOR) is a central regulator of cellular metabolism. The importance of mTORC1 signaling in neuronal development and functions has been highlighted by its strong relationship with many neurological and neuropsychiatric diseases. Previous studies demonstrated that hyperactivation of mTORC1 in forebrain recapitulates tuberous sclerosis and neurodegeneration. In the mouse cerebellum, Purkinje cell-specific knockout of Tsc1/2 has been implicated in autistic-like behaviors. However, since TSC1/2 activity does not always correlate with clinical manifestations as evident in some cases of tuberous sclerosis, the intriguing possibility is raised that phenotypes observed in Tsc1/2 knockout mice cannot be attributable solely to mTORC1 hyperactivation. Here we generated transgenic mice in which mTORC1 signaling is directly hyperactivated in Purkinje cells. The transgenic mice exhibited impaired synapse elimination of climbing fibers and motor discoordination without affecting social behaviors. Furthermore, mTORC1 hyperactivation induced prominent apoptosis of Purkinje cells, accompanied with dysregulated cellular homeostasis including cell enlargement, increased mitochondrial respiratory activity, and activation of pseudohypoxic response. These findings suggest the different contributions between hyperactivated mTORC1 and Tsc1/2 knockout in social behaviors, and reveal the perturbations of cellular homeostasis by hyperactivated mTORC1 as possible underlying mechanisms of neuronal dysfunctions and death in tuberous sclerosis and neurodegenerative diseases.
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76
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Di Rocco G, Baldari S, Pani G, Toietta G. Stem cells under the influence of alcohol: effects of ethanol consumption on stem/progenitor cells. Cell Mol Life Sci 2019; 76:231-244. [PMID: 30306211 PMCID: PMC6339663 DOI: 10.1007/s00018-018-2931-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 09/10/2018] [Accepted: 10/01/2018] [Indexed: 12/13/2022]
Abstract
Stem cells drive embryonic and fetal development. In several adult tissues, they retain the ability to self-renew and differentiate into a variety of specialized cells, thus contributing to tissue homeostasis and repair throughout life span. Alcohol consumption is associated with an increased risk for several diseases and conditions. Growing and developing tissues are particularly vulnerable to alcohol's influence, suggesting that stem- and progenitor-cell function could be affected. Accordingly, recent studies have revealed the possible relevance of alcohol exposure in impairing stem-cell properties, consequently affecting organ development and injury response in different tissues. Here, we review the main studies describing the effects of alcohol on different types of progenitor/stem cells including neuronal, hepatic, intestinal and adventitial progenitor cells, bone-marrow-derived stromal cell, dental pulp, embryonic and hematopoietic stem cells, and tumor-initiating cells. A better understanding of the nature of the cellular damage induced by chronic and episodic heavy (binge) drinking is critical for the improvement of current therapeutic strategies designed to treat patients suffering from alcohol-related disorders.
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Affiliation(s)
- Giuliana Di Rocco
- Department of Research, Advanced Diagnostic, and Technological Innovation, Translational Research Area, IRCCS Regina Elena National Cancer Institute, Via E. Chianesi 53, 00144, Rome, Italy
| | - Silvia Baldari
- Department of Research, Advanced Diagnostic, and Technological Innovation, Translational Research Area, IRCCS Regina Elena National Cancer Institute, Via E. Chianesi 53, 00144, Rome, Italy
| | - Giovambattista Pani
- Institute of General Pathology, Laboratory of Cell Signaling, Catholic University Medical School, Largo F. Vito 1, 00168, Rome, Italy
| | - Gabriele Toietta
- Department of Research, Advanced Diagnostic, and Technological Innovation, Translational Research Area, IRCCS Regina Elena National Cancer Institute, Via E. Chianesi 53, 00144, Rome, Italy.
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77
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Cox RL, Calderon de Anda F, Mangoubi T, Yoshii A. Multiple Critical Periods for Rapamycin Treatment to Correct Structural Defects in Tsc-1-Suppressed Brain. Front Mol Neurosci 2018; 11:409. [PMID: 30467464 PMCID: PMC6237075 DOI: 10.3389/fnmol.2018.00409] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 10/18/2018] [Indexed: 11/18/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant neurogenetic disorder affecting the brain and other vital organs. Neurological symptoms include epilepsy, intellectual disability, and autism. TSC is caused by a loss-of-function mutation in the TSC1 or TSC2 gene. These gene products form a protein complex and normally suppress mammalian target of rapamycin (mTOR) activity. mTOR inhibitors have been used to treat subependymal glioma (SEGA) that is a brain tumor characteristic of TSC. However, neuropathology of TSC also involves dysregulated cortical circuit formation including neuronal migration, axodendritic differentiation, and synapse formation. It is currently unknown to what extent mTOR signaling inhibitors correct an alteration in neuronal morphology that have already formed prior to the treatment. Here, we address the efficacy of rapamycin treatment on neuronal migration and dendrite formation. Using in utero electroporation, we suppressed Tsc1 expression in a fraction of neuronal progenitor cells during the fetal period. In embryonic brain slices, we found that more Tsc1-suppressed cells remained within the periventricular zone, and rapamycin treatment facilitated neuronal migration. Postnatally, Tsc1-suppressed pyramidal neurons showed more complex branching of basal dendrites and a higher spine density at postnatal day (P) 28. Aberrant arborization was normalized by rapamycin administration every other day between P1 and P13 but not P15 and P27. In contrast, abnormal spine maturation improved by rapamycin treatment between P15 and P27 but not P1 and P13. Our results indicate that there are multiple critical windows for correcting different aspects of structural abnormalities in TSC, and the responses depend on the stage of neuronal circuit formation. These data warrant a search for an additional therapeutic target to treat neurological symptoms of TSC.
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Affiliation(s)
- Rebecca L Cox
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, United States.,Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY, United States
| | - Froylan Calderon de Anda
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, United States.,Center for Molecular Neurobiology Hamburg, Research Group Neuronal Development, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tomer Mangoubi
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Akira Yoshii
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, United States.,Department of Anatomy & Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
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78
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Sundberg M, Tochitsky I, Buchholz DE, Winden K, Kujala V, Kapur K, Cataltepe D, Turner D, Han MJ, Woolf CJ, Hatten ME, Sahin M. Purkinje cells derived from TSC patients display hypoexcitability and synaptic deficits associated with reduced FMRP levels and reversed by rapamycin. Mol Psychiatry 2018; 23:2167-2183. [PMID: 29449635 PMCID: PMC6093816 DOI: 10.1038/s41380-018-0018-4] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 12/06/2017] [Accepted: 12/11/2017] [Indexed: 12/11/2022]
Abstract
Accumulating evidence suggests that cerebellar dysfunction early in life is associated with autism spectrum disorder (ASD), but the molecular mechanisms underlying the cerebellar deficits at the cellular level are unclear. Tuberous sclerosis complex (TSC) is a neurocutaneous disorder that often presents with ASD. Here, we developed a cerebellar Purkinje cell (PC) model of TSC with patient-derived human induced pluripotent stem cells (hiPSCs) to characterize the molecular mechanisms underlying cerebellar abnormalities in ASD and TSC. Our results show that hiPSC-derived PCs from patients with pathogenic TSC2 mutations displayed mTORC1 pathway hyperactivation, defects in neuronal differentiation and RNA regulation, hypoexcitability and reduced synaptic activity when compared with those derived from controls. Our gene expression analyses revealed downregulation of several components of fragile X mental retardation protein (FMRP) targets in TSC2-deficient hiPSC-PCs. We detected decreased expression of FMRP, glutamate receptor δ2 (GRID2), and pre- and post-synaptic markers such as synaptophysin and PSD95 in the TSC2-deficient hiPSC-PCs. The mTOR inhibitor rapamycin rescued the deficits in differentiation, synaptic dysfunction, and hypoexcitability of TSC2 mutant hiPSC-PCs in vitro. Our findings suggest that these gene expression changes and cellular abnormalities contribute to aberrant PC function during development in TSC affected individuals.
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Affiliation(s)
- Maria Sundberg
- Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA
| | - Ivan Tochitsky
- Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - David E Buchholz
- Laboratory of Developmental Neurobiology, The Rockefeller University, New York, NY, USA
| | - Kellen Winden
- Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ville Kujala
- Harvard John A. Paulson School of Engineering and Applied Sciences, Boston, MA, USA
| | - Kush Kapur
- Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Deniz Cataltepe
- Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Daria Turner
- Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Min-Joon Han
- Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Clifford J Woolf
- Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA
| | - Mary E Hatten
- Laboratory of Developmental Neurobiology, The Rockefeller University, New York, NY, USA
| | - Mustafa Sahin
- Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA.
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79
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Hasani S, Boroujeni ME, Aliaghaei A, Baghai K, Rostami A. Dopaminergic induction of human adipose-derived mesenchymal stem cells is accompanied by transcriptional activation of autophagy. Cell Biol Int 2018; 42:1688-1694. [DOI: 10.1002/cbin.11056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Accepted: 09/16/2018] [Indexed: 12/11/2022]
Affiliation(s)
- Sanaz Hasani
- Faculty of Medical Biotechnology; Department of Stem Cells and Regenerative Medicine; National Institute of Genetic Engineering and Biotechnology; Tehran Iran
| | - Mahdi Eskandarian Boroujeni
- Faculty of Medical Biotechnology; Department of Stem Cells and Regenerative Medicine; National Institute of Genetic Engineering and Biotechnology; Tehran Iran
| | - Abbas Aliaghaei
- Cell Biology and Anatomical Sciences; School of Medicine; Shahid Beheshti University of Medical Sciences; Tehran Iran
| | - Kaveh Baghai
- Basic and Molecular Epidemiology of Gastrointestinal Disorder Research center; Research institute for Gastroenterology and Liver Diseases; Shahid Beheshti University of Medical Sciences; Tehran Iran
| | - Amin Rostami
- Gastroenterology and Liver Disease Research Center; Research institute for Gastroenterology and Liver Diseases; Shahid Beheshti University of Medical Sciences; Tehran Iran
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80
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La HM, Chan AL, Legrand JMD, Rossello FJ, Gangemi CG, Papa A, Cheng Q, Morand EF, Hobbs RM. GILZ-dependent modulation of mTORC1 regulates spermatogonial maintenance. Development 2018; 145:dev.165324. [PMID: 30126904 DOI: 10.1242/dev.165324] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 08/06/2018] [Indexed: 12/15/2022]
Abstract
Male fertility is dependent on spermatogonial stem cells (SSCs) that self-renew and produce differentiating germ cells. Growth factors produced within the testis are essential for SSC maintenance but intrinsic factors that dictate the SSC response to these stimuli are poorly characterised. Here, we have studied the role of GILZ, a TSC22D family protein and spermatogenesis regulator, in spermatogonial function and signalling. Although broadly expressed in the germline, GILZ was prominent in undifferentiated spermatogonia and Gilz deletion in adults resulted in exhaustion of the GFRα1+ SSC-containing population and germline degeneration. GILZ loss was associated with mTORC1 activation, suggesting enhanced growth factor signalling. Expression of deubiquitylase USP9X, an mTORC1 modulator required for spermatogenesis, was disrupted in Gilz mutants. Treatment with an mTOR inhibitor rescued GFRα1+ spermatogonial failure, indicating that GILZ-dependent mTORC1 inhibition is crucial for SSC maintenance. Analysis of cultured undifferentiated spermatogonia lacking GILZ confirmed aberrant activation of ERK MAPK upstream mTORC1 plus USP9X downregulation and interaction of GILZ with TSC22D proteins. Our data indicate an essential role for GILZ-TSC22D complexes in ensuring the appropriate response of undifferentiated spermatogonia to growth factors via distinct inputs to mTORC1.
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Affiliation(s)
- Hue M La
- Australian Regenerative Medicine Institute, Monash University, Melbourne, Victoria 3800, Australia.,Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria 3800, Australia
| | - Ai-Leen Chan
- Australian Regenerative Medicine Institute, Monash University, Melbourne, Victoria 3800, Australia.,Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria 3800, Australia
| | - Julien M D Legrand
- Australian Regenerative Medicine Institute, Monash University, Melbourne, Victoria 3800, Australia.,Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria 3800, Australia
| | - Fernando J Rossello
- Australian Regenerative Medicine Institute, Monash University, Melbourne, Victoria 3800, Australia.,Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria 3800, Australia
| | - Christina G Gangemi
- Australian Regenerative Medicine Institute, Monash University, Melbourne, Victoria 3800, Australia.,Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria 3800, Australia
| | - Antonella Papa
- Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria 3800, Australia
| | - Qiang Cheng
- Centre for Inflammatory Diseases, School of Clinical Sciences at Monash Health, Monash University, Melbourne, Victoria 3800, Australia
| | - Eric F Morand
- Centre for Inflammatory Diseases, School of Clinical Sciences at Monash Health, Monash University, Melbourne, Victoria 3800, Australia
| | - Robin M Hobbs
- Australian Regenerative Medicine Institute, Monash University, Melbourne, Victoria 3800, Australia .,Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria 3800, Australia
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81
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Haller S, Kapuria S, Riley RR, O'Leary MN, Schreiber KH, Andersen JK, Melov S, Que J, Rando TA, Rock J, Kennedy BK, Rodgers JT, Jasper H. mTORC1 Activation during Repeated Regeneration Impairs Somatic Stem Cell Maintenance. Cell Stem Cell 2018; 21:806-818.e5. [PMID: 29220665 DOI: 10.1016/j.stem.2017.11.008] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 07/29/2017] [Accepted: 11/07/2017] [Indexed: 12/21/2022]
Abstract
The balance between self-renewal and differentiation ensures long-term maintenance of stem cell (SC) pools in regenerating epithelial tissues. This balance is challenged during periods of high regenerative pressure and is often compromised in aged animals. Here, we show that target of rapamycin (TOR) signaling is a key regulator of SC loss during repeated regenerative episodes. In response to regenerative stimuli, SCs in the intestinal epithelium of the fly and in the tracheal epithelium of mice exhibit transient activation of TOR signaling. Although this activation is required for SCs to rapidly proliferate in response to damage, repeated rounds of damage lead to SC loss. Consistently, age-related SC loss in the mouse trachea and in muscle can be prevented by pharmacologic or genetic inhibition, respectively, of mammalian target of rapamycin complex 1 (mTORC1) signaling. These findings highlight an evolutionarily conserved role of TOR signaling in SC function and identify repeated rounds of mTORC1 activation as a driver of age-related SC decline.
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Affiliation(s)
- Samantha Haller
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945-1400, USA; Immunology Discovery, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Subir Kapuria
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945-1400, USA
| | - Rebeccah R Riley
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945-1400, USA
| | - Monique N O'Leary
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945-1400, USA; Mount Holyoke College, South Hadley, MA 01075, USA
| | - Katherine H Schreiber
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945-1400, USA; University of Michigan, Ann Arbor, MI 48109, USA
| | - Julie K Andersen
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945-1400, USA
| | - Simon Melov
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945-1400, USA
| | - Jianwen Que
- Department of Medicine, Columbia University, New York, NY 10032, USA
| | - Thomas A Rando
- Paul F. Glenn Laboratories for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94304, USA
| | - Jason Rock
- Department of Anatomy, UCSF School of Medicine, San Francisco, CA 94117, USA
| | - Brian K Kennedy
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945-1400, USA
| | - Joseph T Rodgers
- Paul F. Glenn Laboratories for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94304, USA; Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research, USC, Los Angeles, CA 90033, USA
| | - Heinrich Jasper
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945-1400, USA; Immunology Discovery, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA; Leibniz Institute on Aging, Fritz Lipmann Institute, Jena 07745, Germany.
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82
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Zucco AJ, Pozzo VD, Afinogenova A, Hart RP, Devinsky O, D'Arcangelo G. Neural progenitors derived from Tuberous Sclerosis Complex patients exhibit attenuated PI3K/AKT signaling and delayed neuronal differentiation. Mol Cell Neurosci 2018; 92:149-163. [PMID: 30144504 DOI: 10.1016/j.mcn.2018.08.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 07/23/2018] [Accepted: 08/20/2018] [Indexed: 12/20/2022] Open
Abstract
Tuberous Sclerosis Complex (TSC) is a disease caused by autosomal dominant mutations in the TSC1 or TSC2 genes, and is characterized by tumor susceptibility, brain lesions, seizures and behavioral impairments. The TSC1 and TSC2 genes encode proteins forming a complex (TSC), which is a major regulator and suppressor of mammalian target of rapamycin complex 1 (mTORC1), a signaling complex that promotes cell growth and proliferation. TSC1/2 loss of heterozygosity (LOH) and the subsequent complete loss of TSC regulatory activity in null cells causes mTORC1 dysregulation and TSC-associated brain lesions or other tissue tumors. However, it is not clear whether TSC1/2 heterozygous brain cells are abnormal and contribute to TSC neuropathology. To investigate this issue, we generated induced pluripotent stem cells (iPSCs) from TSC patients and unaffected controls, and utilized these to obtain neural progenitor cells (NPCs) and differentiated neurons in vitro. These patient-derived TSC2 heterozygous NPCs were delayed in their ability to differentiate into neurons. Patient-derived progenitor cells also exhibited a modest activation of mTORC1 signaling downstream of TSC, and a marked attenuation of upstream PI3K/AKT signaling. We further show that pharmacologic PI3K or AKT inhibition, but not mTORC1 inhibition, causes a neuronal differentiation delay, mimicking the patient phenotype. Together these data suggest that heterozygous TSC2 mutations disrupt neuronal development, potentially contributing to the disease neuropathology, and that this defect may result from dysregulated PI3K/AKT signaling in neural progenitor cells.
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Affiliation(s)
- Avery J Zucco
- Graduate Program in Neuroscience, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, United States of America; Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey, Piscataway, NJ, United States of America
| | - Valentina Dal Pozzo
- Graduate Program in Neuroscience, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, United States of America; Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey, Piscataway, NJ, United States of America
| | - Alina Afinogenova
- Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey, Piscataway, NJ, United States of America
| | - Ronald P Hart
- Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey, Piscataway, NJ, United States of America; Human Genetics Institute of New Jersey, Piscataway, NJ, United States of America
| | - Orrin Devinsky
- NYU Comprehensive Epilepsy Center, NYU Langone School of Medicine, New York, NY, United States of America
| | - Gabriella D'Arcangelo
- Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey, Piscataway, NJ, United States of America; Human Genetics Institute of New Jersey, Piscataway, NJ, United States of America.
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83
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Blair JD, Hockemeyer D, Bateup HS. Genetically engineered human cortical spheroid models of tuberous sclerosis. Nat Med 2018; 24:1568-1578. [PMID: 30127391 PMCID: PMC6261470 DOI: 10.1038/s41591-018-0139-y] [Citation(s) in RCA: 126] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 07/06/2018] [Indexed: 01/01/2023]
Abstract
Tuberous sclerosis complex (TSC) is a multisystem developmental disorder caused by mutations in the TSC1 or TSC2 genes, whose protein products are negative regulators of mechanistic target of rapamycin complex 1 signaling. Hallmark pathologies of TSC are cortical tubers-regions of dysmorphic, disorganized neurons and glia in the cortex that are linked to epileptogenesis. To determine the developmental origin of tuber cells, we established human cellular models of TSC by CRISPR-Cas9-mediated gene editing of TSC1 or TSC2 in human pluripotent stem cells (hPSCs). Using heterozygous TSC2 hPSCs with a conditional mutation in the functional allele, we show that mosaic biallelic inactivation during neural progenitor expansion is necessary for the formation of dysplastic cells and increased glia production in three-dimensional cortical spheroids. Our findings provide support for the second-hit model of cortical tuber formation and suggest that variable developmental timing of somatic mutations could contribute to the heterogeneity in the neurological presentation of TSC.
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Affiliation(s)
- John D Blair
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Dirk Hockemeyer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Helen S Bateup
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA. .,Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA.
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84
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Rothan HA, Fang S, Mahesh M, Byrareddy SN. Zika Virus and the Metabolism of Neuronal Cells. Mol Neurobiol 2018; 56:2551-2557. [PMID: 30043260 DOI: 10.1007/s12035-018-1263-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Accepted: 07/18/2018] [Indexed: 02/07/2023]
Abstract
Zika virus (ZIKV) infection is associated with abnormal functions of neuronal cells causing neurological disorders such as microcephaly in the newborns and Guillain-Barré syndrome in the adults. Typically, healthy brain growth is associated with normal neural stem cell proliferation, differentiation, and maturation. This process requires a controlled cellular metabolism that is essential for normal migration, axonal elongation, and dendrite morphogenesis of newly generated neurons. Thus, the remarkable changes in the cellular metabolism during early stages of neuronal stem cell differentiation are crucial for brain development. Recent studies show that ZIKV directly infects neuronal stem cells in the fetus and impairs brain growth. In this review, we highlighted the fact that the activation of P53 and inhibition of the mTOR pathway by ZIKV infection to neuronal stem cells induces early shifting from glycolysis to oxidative phosphorylation (OXPHOS) may induce immature differentiation, apoptosis, and stem cell exhaustion. We hypothesize that ZIKV infection to mature myelin-producing cells and resulting metabolic shift may lead to the development of neurological diseases, such as Guillain-Barré syndrome. Thus, the effects of ZIKV on the cellular metabolism of neuronal cells may lead to the incidence of neurological disorders as observed recently during ZIKV infection.
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Affiliation(s)
- Hussin A Rothan
- Center for Biomedical Engineering & Technology, School of Medicine, University of Maryland, Baltimore, MD, USA. .,Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, USA.
| | - Shengyun Fang
- Center for Biomedical Engineering & Technology, School of Medicine, University of Maryland, Baltimore, MD, USA.,Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Mohan Mahesh
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, LA, 70433, USA
| | - Siddappa N Byrareddy
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA. .,Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE, USA. .,Department of Pharmacology and Experimental Neuroscience, College of Medicine, University of Nebraska Medical Centre (UNMC), Omaha, NE, 68198-5800, USA.
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85
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Abstract
The mechanistic target of rapamycin (mTOR) is an important signaling hub that integrates environmental information regarding energy availability and stimulates anabolic molecular processes and cell growth. Abnormalities in this pathway have been identified in several syndromes in which autism spectrum disorder (ASD) is highly prevalent. Several studies have investigated mTOR signaling in developmental and neuronal processes that, when dysregulated, could contribute to the development of ASD. Although many potential mechanisms still remain to be fully understood, these associations are of great interest because of the clinical availability of mTOR inhibitors. Clinical trials evaluating the efficacy of mTOR inhibitors to improve neurodevelopmental outcomes have been initiated.
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Affiliation(s)
- Kellen D. Winden
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Darius Ebrahimi-Fakhari
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Mustafa Sahin
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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86
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Blair JD, Hockemeyer D, Doudna JA, Bateup HS, Floor SN. Widespread Translational Remodeling during Human Neuronal Differentiation. Cell Rep 2018; 21:2005-2016. [PMID: 29141229 DOI: 10.1016/j.celrep.2017.10.095] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 10/13/2017] [Accepted: 10/24/2017] [Indexed: 01/04/2023] Open
Abstract
Faithful cellular differentiation requires temporally precise activation of gene expression programs, which are coordinated at the transcriptional and translational levels. Neurons express the most complex set of mRNAs of any human tissue, but translational changes during neuronal differentiation remain incompletely understood. Here, we induced forebrain neuronal differentiation of human embryonic stem cells (hESCs) and measured genome-wide RNA and translation levels with transcript-isoform resolution. We found that thousands of genes change translation status during differentiation without a corresponding change in RNA level. Specifically, we identified mTOR signaling as a key driver for elevated translation of translation-related genes in hESCs. In contrast, translational repression in active neurons is mediated by regulatory sequences in 3' UTRs. Together, our findings identify extensive translational control changes during human neuronal differentiation and a crucial role of 3' UTRs in driving cell-type-specific translation.
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Affiliation(s)
- John D Blair
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Dirk Hockemeyer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Jennifer A Doudna
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA; Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Molecular Biophysics and Imaging Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Helen S Bateup
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - Stephen N Floor
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA.
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87
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Role of mTOR Complexes in Neurogenesis. Int J Mol Sci 2018; 19:ijms19051544. [PMID: 29789464 PMCID: PMC5983636 DOI: 10.3390/ijms19051544] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/13/2018] [Accepted: 05/16/2018] [Indexed: 12/22/2022] Open
Abstract
Dysregulation of neural stem cells (NSCs) is associated with several neurodevelopmental disorders, including epilepsy and autism spectrum disorder. The mammalian target of rapamycin (mTOR) integrates the intracellular signals to control cell growth, nutrient metabolism, and protein translation. mTOR regulates many functions in the development of the brain, such as proliferation, differentiation, migration, and dendrite formation. In addition, mTOR is important in synaptic formation and plasticity. Abnormalities in mTOR activity is linked with severe deficits in nervous system development, including tumors, autism, and seizures. Dissecting the wide-ranging roles of mTOR activity during critical periods in development will greatly expand our understanding of neurogenesis.
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88
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mTOR Signaling and Neural Stem Cells: The Tuberous Sclerosis Complex Model. Int J Mol Sci 2018; 19:ijms19051474. [PMID: 29772672 PMCID: PMC5983755 DOI: 10.3390/ijms19051474] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 05/04/2018] [Accepted: 05/11/2018] [Indexed: 12/24/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR), a serine-threonine kinase, plays a pivotal role in regulating cell growth and proliferation. Notably, a great deal of evidence indicates that mTOR signaling is also crucial in controlling proliferation and differentiation of several stem cell compartments. Consequently, dysregulation of the mTOR pathway is often associated with a variety of disease, such as cancer and metabolic and genetic disorders. For instance, hyperactivation of mTORC1 in neural stem cells (NSCs) is associated with the insurgence of neurological manifestation characterizing tuberous sclerosis complex (TSC). In this review, we survey the recent contributions of TSC physiopathology studies to understand the role of mTOR signaling in both neurogenesis and tumorigenesis and discuss how these new insights can contribute to developing new therapeutic strategies for neurological diseases and cancer.
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89
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Zordan P, Cominelli M, Cascino F, Tratta E, Poliani PL, Galli R. Tuberous sclerosis complex-associated CNS abnormalities depend on hyperactivation of mTORC1 and Akt. J Clin Invest 2018; 128:1688-1706. [PMID: 29389670 DOI: 10.1172/jci96342] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 01/30/2018] [Indexed: 12/11/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a dominantly inherited disease caused by hyperactivation of the mTORC1 pathway and characterized by the development of hamartomas and benign tumors, including in the brain. Among the neurological manifestations associated with TSC, the tumor progression of static subependymal nodules (SENs) into subependymal giant cell astrocytomas (SEGAs) is one of the major causes of morbidity and shortened life expectancy. To date, mouse modeling has failed in reproducing these 2 lesions. Here we report that simultaneous hyperactivation of mTORC1 and Akt pathways by codeletion of Tsc1 and Pten, selectively in postnatal neural stem cells (pNSCs), is required for the formation of bona fide SENs and SEGAs. Notably, both lesions closely recapitulate the pathognomonic morphological and molecular features of the corresponding human abnormalities. The establishment of long-term expanding pNSC lines from mouse SENs and SEGAs made possible the identification of mTORC2 as one of the mediators conferring tumorigenic potential to SEGA pNSCs. Notably, in spite of concurrent Akt hyperactivation in mouse brain lesions, single mTOR inhibition by rapamycin was sufficient to strongly impair mouse SEGA growth. This study provides evidence that, concomitant with mTORC1 hyperactivation, sustained activation of Akt and mTORC2 in pNSCs is a mandatory step for the induction of SENs and SEGAs, and, at the same time, makes available an unprecedented NSC-based in vivo/in vitro model to be exploited for identifying actionable targets in TSC.
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Affiliation(s)
- Paola Zordan
- Neural Stem Cell Biology Unit, Division of Regenerative Medicine, Stem Cells and Gene Therapy, San Raffaele Scientific Institute, Milan, Italy
| | - Manuela Cominelli
- Pathology Unit, Molecular and Translational Medicine Department, University of Brescia, Brescia, Italy
| | - Federica Cascino
- Neural Stem Cell Biology Unit, Division of Regenerative Medicine, Stem Cells and Gene Therapy, San Raffaele Scientific Institute, Milan, Italy
| | - Elisa Tratta
- Pathology Unit, Molecular and Translational Medicine Department, University of Brescia, Brescia, Italy
| | - Pietro L Poliani
- Pathology Unit, Molecular and Translational Medicine Department, University of Brescia, Brescia, Italy
| | - Rossella Galli
- Neural Stem Cell Biology Unit, Division of Regenerative Medicine, Stem Cells and Gene Therapy, San Raffaele Scientific Institute, Milan, Italy
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90
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Magini A, Polchi A, Di Meo D, Mariucci G, Sagini K, De Marco F, Cassano T, Giovagnoli S, Dolcetta D, Emiliani C. TFEB activation restores migration ability to Tsc1-deficient adult neural stem/progenitor cells. Hum Mol Genet 2018. [PMID: 28637240 DOI: 10.1093/hmg/ddx214] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disorder caused by mutations in either of two genes, TSC1 or TSC2, resulting in the constitutive activation of the mammalian target of rapamycin complex 1 (mTORC1). mTOR inhibitors are now considered the treatment of choice for TSC disease. A major pathological feature of TSC is the development of subependymal giant cell astrocytomas (SEGAs) in the brain. Nowadays, it is thought that SEGAs could be a consequence of aberrant aggregation and migration of neural stem/progenitor cells (NSPCs). Therefore, reactivation of cell migration of NSPCs might be the crucial step for the treatment of patients. In order to identify potential in vitro targets activating migration, we generated Tsc1-deficient NSPCs. These cells summarize most of the biochemical and morphological characteristics of TSC neural cells, such as the mTORC1 activation, the formation of abnormally enlarged astrocytes-like cells, the reduction of autophagy flux and the impairment of cell migration. Moreover, nuclear translocation, namely activation of the transcription factor EB (TFEB) was markedly impaired. Herein, we show that compounds such as everolimus, ionomycin and curcumin, which directly or indirectly stimulate TFEB nuclear translocation, restore Tsc1-deficient NSPC migration. Our data suggest that reduction of TFEB activation, caused by mTORC1 hyperactivation, contributes to the migration deficit characterizing Tsc1-deficient NSPCs. The present work highlights TFEB as a druggable protein target for SEGAs therapy, which can be additionally or alternatively exploited for the mTORC1-directed inhibitory approach.
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Affiliation(s)
- Alessandro Magini
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Via del Giochetto, 06122 Perugia, Italy
| | - Alice Polchi
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Via del Giochetto, 06122 Perugia, Italy
| | - Danila Di Meo
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Via del Giochetto, 06122 Perugia, Italy
| | - Giuseppina Mariucci
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo 1, 06123, Perugia, Italy
| | - Krizia Sagini
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Via del Giochetto, 06122 Perugia, Italy
| | - Federico De Marco
- UOSD SAFU, RiDAIT Department, The Regina Elena National Cancer Institute, via Elio Chianesi 53, 00144, Rome, Italy
| | - Tommaso Cassano
- Department of Clinical and Experimental Medicine, Medical School, University of Foggia, viale Luigi Pinto, 1, 71100, Foggia, Italy
| | - Stefano Giovagnoli
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo 1, 06123, Perugia, Italy
| | - Diego Dolcetta
- UOSD SAFU, RiDAIT Department, The Regina Elena National Cancer Institute, via Elio Chianesi 53, 00144, Rome, Italy
| | - Carla Emiliani
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Via del Giochetto, 06122 Perugia, Italy.,Centre of Excellence on Innovative Nanostructure Materials (CEMIN), University of Perugia, Via Elece di Sotto 8, 06123 Perugia, Italy
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91
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Kim TH, Sung SE, Cheal Yoo J, Park JY, Yi GS, Heo JY, Lee JR, Kim NS, Lee DY. Copine1 regulates neural stem cell functions during brain development. Biochem Biophys Res Commun 2017; 495:168-173. [PMID: 29101038 DOI: 10.1016/j.bbrc.2017.10.167] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 10/30/2017] [Indexed: 12/14/2022]
Abstract
Copine 1 (CPNE1) is a well-known phospholipid binding protein in plasma membrane of various cell types. In brain cells, CPNE1 is closely associated with AKT signaling pathway, which is important for neural stem cell (NSC) functions during brain development. Here, we investigated the role of CPNE1 in the regulation of brain NSC functions during brain development and determined its underlying mechanism. In this study, abundant expression of CPNE1 was observed in neural lineage cells including NSCs and immature neurons in human. With mouse brain tissues in various developmental stages, we found that CPNE1 expression was higher at early embryonic stages compared to postnatal and adult stages. To model developing brain in vitro, we used primary NSCs derived from mouse embryonic hippocampus. Our in vitro study shows decreased proliferation and multi-lineage differentiation potential in CPNE1 deficient NSCs. Finally, we found that the deficiency of CPNE1 downregulated mTOR signaling in embryonic NSCs. These data demonstrate that CPNE1 plays a key role in the regulation of NSC functions through the activation of AKT-mTOR signaling pathway during brain development.
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Affiliation(s)
- Tae Hwan Kim
- Rare Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea; Department of Biochemistry, Chungnam National University School of Medicine, 266 Munhwa-ro, Jung-gu, Daejeon 35015, South Korea; Department of Medical Science, Chungnam National University School of Medicine, 266 Munhwa-ro, Jung-gu, Daejeon 35015, South Korea
| | - Soo-Eun Sung
- Genome Editing Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Jae Cheal Yoo
- Department of Bio and Brain Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Jae-Yong Park
- School of Biosystem and Biomedical Science, College of Health Science, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, South Korea
| | - Gwan-Su Yi
- Department of Bio and Brain Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Jun Young Heo
- Department of Biochemistry, Chungnam National University School of Medicine, 266 Munhwa-ro, Jung-gu, Daejeon 35015, South Korea; Department of Medical Science, Chungnam National University School of Medicine, 266 Munhwa-ro, Jung-gu, Daejeon 35015, South Korea
| | - Jae-Ran Lee
- Rare Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Nam-Soon Kim
- Rare Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Da Yong Lee
- Rare Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea.
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92
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Hanai S, Sukigara S, Dai H, Owa T, Horike SI, Otsuki T, Saito T, Nakagawa E, Ikegaya N, Kaido T, Sato N, Takahashi A, Sugai K, Saito Y, Sasaki M, Hoshino M, Goto YI, Koizumi S, Itoh M. Pathologic Active mTOR Mutation in Brain Malformation with Intractable Epilepsy Leads to Cell-Autonomous Migration Delay. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:1177-1185. [PMID: 28427592 DOI: 10.1016/j.ajpath.2017.01.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 01/19/2017] [Indexed: 01/08/2023]
Abstract
The activation of phosphatidylinositol 3-kinase-AKTs-mammalian target of rapamycin cell signaling pathway leads to cell overgrowth and abnormal migration and results in various types of cortical malformations, such as hemimegalencephaly (HME), focal cortical dysplasia, and tuberous sclerosis complex. However, the pathomechanism underlying abnormal cell migration remains unknown. With the use of fetal mouse brain, we performed causative gene analysis of the resected brain tissues from a patient with HME and investigated the pathogenesis. We obtained a novel somatic mutation of the MTOR gene, having approximately 11% and 7% mutation frequency in the resected brain tissues. Moreover, we revealed that the MTOR mutation resulted in hyperphosphorylation of its downstream molecules, S6 and 4E-binding protein 1, and delayed cell migration on the radial glial fiber and did not affect other cells. We suspect cell-autonomous migration arrest on the radial glial foot by the active MTOR mutation and offer potential explanations for why this may lead to cortical malformations such as HME.
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Affiliation(s)
- Sae Hanai
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, Kodaira, Japan
| | - Sayuri Sukigara
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, Kodaira, Japan
| | - Hongmei Dai
- Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, Kodaira, Japan
| | - Tomoo Owa
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, Kodaira, Japan
| | - Shin-Ichi Horike
- Division of Functional Genomics, Advanced Science Research Center Kanazawa University, Kanazawa, Japan
| | - Taisuke Otsuki
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Neurosurgery, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Takashi Saito
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Child Neurology, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Eiji Nakagawa
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Child Neurology, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Naoki Ikegaya
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Neurosurgery, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Takanobu Kaido
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Neurosurgery, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Noriko Sato
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Radiology, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Akio Takahashi
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Neurosurgery, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Kenji Sugai
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Child Neurology, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Yuko Saito
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Laboratory Medicine, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Masayuki Sasaki
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Child Neurology, Hospital of National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Mikio Hoshino
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, Kodaira, Japan
| | - Yu-Ichi Goto
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, Kodaira, Japan
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Japan
| | - Masayuki Itoh
- Epilepsy Center, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Kodaira, Japan; Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, Kodaira, Japan.
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93
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Li L. The Molecular Mechanism of Glucagon-Like Peptide-1 Therapy in Alzheimer's Disease, Based on a Mechanistic Target of Rapamycin Pathway. CNS Drugs 2017; 31:535-549. [PMID: 28540646 DOI: 10.1007/s40263-017-0431-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The mechanistic target of rapamycin (mTOR) is an important molecule that connects aging, lifespan, energy balance, glucose and lipid metabolism, and neurodegeneration. Rapamycin exerts effects in numerous biological activities via its target protein, playing a key role in energy balance, regulation of autophagy, extension of lifespan, immunosuppression, and protection against neurodegeneration. There are many similar pathophysiological processes and molecular pathways between Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM), and pharmacologic agents used to treat T2DM, including glucagon-like peptide-1 (GLP-1) analogs, seem to be beneficial for AD. mTOR mediates the effects of GLP-1 analogs in the treatment of T2DM; hence, I hypothesize that mTOR is a key molecule for mediating the protective effects of GLP-1 for AD.
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Affiliation(s)
- Lin Li
- Key Laboratory of Cellular Physiology, Shanxi Medical University, Taiyuan, Shanxi, China.
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94
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Martin KR, Zhou W, Bowman MJ, Shih J, Au KS, Dittenhafer-Reed KE, Sisson KA, Koeman J, Weisenberger DJ, Cottingham SL, DeRoos ST, Devinsky O, Winn ME, Cherniack AD, Shen H, Northrup H, Krueger DA, MacKeigan JP. The genomic landscape of tuberous sclerosis complex. Nat Commun 2017. [PMID: 28643795 PMCID: PMC5481739 DOI: 10.1038/ncomms15816] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a rare genetic disease causing multisystem growth of benign tumours and other hamartomatous lesions, which leads to diverse and debilitating clinical symptoms. Patients are born with TSC1 or TSC2 mutations, and somatic inactivation of wild-type alleles drives MTOR activation; however, second hits to TSC1/TSC2 are not always observed. Here, we present the genomic landscape of TSC hamartomas. We determine that TSC lesions contain a low somatic mutational burden relative to carcinomas, a subset feature large-scale chromosomal aberrations, and highly conserved molecular signatures for each type exist. Analysis of the molecular signatures coupled with computational approaches reveals unique aspects of cellular heterogeneity and cell origin. Using immune data sets, we identify significant neuroinflammation in TSC-associated brain tumours. Taken together, this molecular catalogue of TSC serves as a resource into the origin of these hamartomas and provides a framework that unifies genomic and transcriptomic dimensions for complex tumours.
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Affiliation(s)
- Katie R Martin
- Center for Cancer and Cell Biology, Van Andel Research Institute, 333 Bostwick Avenue NE, Grand Rapids, Michigan 49503, USA
| | - Wanding Zhou
- Center for Epigenetics, Van Andel Research Institute, 333 Bostwick Avenue NE, Grand Rapids, Michigan 49503, USA
| | - Megan J Bowman
- Bioinformatics and Biostatistics Core, Van Andel Research Institute, 333 Bostwick Avenue NE, Grand Rapids, Michigan 49503, USA
| | - Juliann Shih
- Cancer Program, Broad Institute of Harvard and MIT, 415 Main Street, Cambridge, Massachusetts 02142, USA
| | - Kit Sing Au
- Department of Pediatrics, University of Texas Health Science Center at Houston-McGovern Medical School, 6431 Fannin, Houston, Texas 77030, USA
| | - Kristin E Dittenhafer-Reed
- Center for Cancer and Cell Biology, Van Andel Research Institute, 333 Bostwick Avenue NE, Grand Rapids, Michigan 49503, USA
| | - Kellie A Sisson
- Center for Cancer and Cell Biology, Van Andel Research Institute, 333 Bostwick Avenue NE, Grand Rapids, Michigan 49503, USA
| | - Julie Koeman
- Cytogenetics and Pathology Core, Van Andel Research Institute, 333 Bostwick Avenue NE, Grand Rapids, Michigan 49503, USA
| | - Daniel J Weisenberger
- Norris Comprehensive Cancer Center, University of Southern California, 1450 Biggy Street, Los Angeles, California 90033, USA
| | - Sandra L Cottingham
- Department of Pathology, Spectrum Health System, 100 Michigan Street NE, Grand Rapids, Michigan 49503, USA
| | - Steven T DeRoos
- Division of Pediatric Neurology, Helen DeVos Children's Hospital, Spectrum Health System, 100 Michigan Street NE, Grand Rapids, Michigan 49503, USA
| | - Orrin Devinsky
- Department of Neurology, New York University School of Medicine, 223 E 34 Street, New York, New York 10016, USA
| | - Mary E Winn
- Bioinformatics and Biostatistics Core, Van Andel Research Institute, 333 Bostwick Avenue NE, Grand Rapids, Michigan 49503, USA
| | - Andrew D Cherniack
- Cancer Program, Broad Institute of Harvard and MIT, 415 Main Street, Cambridge, Massachusetts 02142, USA
| | - Hui Shen
- Center for Epigenetics, Van Andel Research Institute, 333 Bostwick Avenue NE, Grand Rapids, Michigan 49503, USA
| | - Hope Northrup
- Department of Pediatrics, University of Texas Health Science Center at Houston-McGovern Medical School, 6431 Fannin, Houston, Texas 77030, USA
| | - Darcy A Krueger
- Division of Neurology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, Ohio 45229, USA
| | - Jeffrey P MacKeigan
- Center for Cancer and Cell Biology, Van Andel Research Institute, 333 Bostwick Avenue NE, Grand Rapids, Michigan 49503, USA.,College of Human Medicine, Michigan State University, 220 Trowbridge Road, East Lansing, Michigan 48824, USA
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95
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Shin J, Kim M, Jung HJ, Cha HL, Suh-Kim H, Ahn S, Jung J, Kim Y, Jun Y, Lee S, Hwang D, Kim J. Characterization of developmental defects in the forebrain resulting from hyperactivated mTOR signaling by integrative analysis of transcriptomic and proteomic data. Sci Rep 2017; 7:2826. [PMID: 28588230 PMCID: PMC5460284 DOI: 10.1038/s41598-017-02842-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 04/19/2017] [Indexed: 12/25/2022] Open
Abstract
Hyperactivated mTOR signaling in the developing brain has been implicated in multiple forms of pathology including tuberous sclerosis complex (TSC). To date, various phenotypic defects such as cortical lamination irregularity, subependymal nodule formation, dysmorphic astrocyte differentiation and dendritic malformation have been described for patients and animal models. However, downstream networks affected in the developing brain by hyperactivated mTOR signaling have yet to be characterized. Here, we present an integrated analysis of transcriptomes and proteomes generated from wild-type and Tsc1/Emx1-Cre forebrains. This led to comprehensive lists of genes and proteins whose expression levels were altered by hyperactivated mTOR signaling. Further incorporation of TSC patient data followed by functional enrichment and network analyses pointed to changes in molecular components and cellular processes associated with neuronal differentiation and morphogenesis as the key downstream events underlying developmental and morphological defects in TSC. Our results provide novel and fundamental molecular bases for understanding hyperactivated mTOR signaling-induced brain defects which can in turn facilitate identification of potential diagnostic markers and therapeutic targets for mTOR signaling-related neurological disorders.
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Affiliation(s)
- Jiheon Shin
- Department of Life Science, Ewha Womans University, Seoul, 03760, Republic of Korea.,Ewha Research Center for Systems Biology, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Minhyung Kim
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, 37666, Republic of Korea
| | - Hee-Jung Jung
- Center for Plant Aging Research, Institute for Basic Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea
| | - Hye Lim Cha
- Department of Anatomy, Ajou University School of Medicine, Suwon, 16499, Republic of Korea
| | - Haeyoung Suh-Kim
- Department of Anatomy, Ajou University School of Medicine, Suwon, 16499, Republic of Korea.,Department of Biomedical Sciences, The Graduate School, Ajou University School of Medicine, Suwon, 16499, Republic of Korea
| | - Sanghyun Ahn
- Center for Plant Aging Research, Institute for Basic Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea
| | - Jaehoon Jung
- Center for Plant Aging Research, Institute for Basic Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea
| | - YounAh Kim
- Center for Plant Aging Research, Institute for Basic Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea
| | - Yukyung Jun
- Department of Life Science, Ewha Womans University, Seoul, 03760, Republic of Korea.,Ewha Research Center for Systems Biology, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Sanghyuk Lee
- Department of Life Science, Ewha Womans University, Seoul, 03760, Republic of Korea.,Ewha Research Center for Systems Biology, Ewha Womans University, Seoul, 03760, Republic of Korea.,Ewha-JAX Research Center for Cancer Immunotherapy, Ewha Womans University, Seoul, 03760, Korea
| | - Daehee Hwang
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, 37666, Republic of Korea. .,Center for Plant Aging Research, Institute for Basic Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea. .,Department of New Biology, DGIST, Daegu, 42988, Republic of Korea.
| | - Jaesang Kim
- Department of Life Science, Ewha Womans University, Seoul, 03760, Republic of Korea. .,Ewha Research Center for Systems Biology, Ewha Womans University, Seoul, 03760, Republic of Korea. .,Ewha-JAX Research Center for Cancer Immunotherapy, Ewha Womans University, Seoul, 03760, Korea.
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96
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Fidaleo M, Cavallucci V, Pani G. Nutrients, neurogenesis and brain ageing: From disease mechanisms to therapeutic opportunities. Biochem Pharmacol 2017; 141:63-76. [PMID: 28539263 DOI: 10.1016/j.bcp.2017.05.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 05/19/2017] [Indexed: 02/08/2023]
Abstract
Appreciation of the physiological relevance of mammalian adult neurogenesis has in recent years rapidly expanded from a phenomenon of homeostatic cell replacement and brain repair to the current view of a complex process involved in high order cognitive functions. In parallel, an array of endogenous or exogenous triggers of neurogenesis has also been identified, among which metabolic and nutritional cues have drawn significant attention. Converging evidence from animal and in vitro studies points to nutrient sensing and energy metabolism as major physiological determinants of neural stem cell fate, and modulators of the whole neurogenic process. While the cellular and molecular circuitries underlying metabolic regulation of neurogenesis are still incompletely understood, the key role of mitochondrial activity and dynamics, and the importance of autophagy have begun to be fully appreciated; moreover, nutrient-sensitive pathways and transducers such as the insulin-IGF cascade, the AMPK/mTOR axis and the transcription regulators CREB and Sirt-1 have been included, beside more established "developmental" signals like Notch and Wnt, in the molecular networks that dictate neural-stem-cell self-renewal, migration and differentiation in response to local and systemic inputs. Many of these nutrient-related cascades are deregulated in the contest of metabolic diseases and in ageing, and may contribute to impaired neurogenesis and thus to cognition defects observed in these conditions. Importantly, accumulating knowledge on the metabolic control of neurogenesis provides a theoretical framework for the trial of new or repurposed drugs capable of interfering with nutrient sensing as enhancers of neurogenesis in the context of neurodegeneration and brain senescence.
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Affiliation(s)
- Marco Fidaleo
- Institute of General Pathology, Università Cattolica School of Medicine, 00168 Rome, Italy
| | - Virve Cavallucci
- Institute of General Pathology, Università Cattolica School of Medicine, 00168 Rome, Italy
| | - Giovambattista Pani
- Institute of General Pathology, Università Cattolica School of Medicine, 00168 Rome, Italy.
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97
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Nikolaeva I, Kazdoba TM, Crowell B, D'Arcangelo G. Differential roles for Akt and mTORC1 in the hypertrophy of Pten mutant neurons, a cellular model of brain overgrowth disorders. Neuroscience 2017; 354:196-207. [PMID: 28457820 DOI: 10.1016/j.neuroscience.2017.04.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 04/19/2017] [Accepted: 04/19/2017] [Indexed: 10/19/2022]
Abstract
Mutations in the PI3K/Akt/mTOR signaling pathway or in the upstream negative regulator Pten cause human brain overgrowth disorders, such as focal cortical dysplasia and megalencephaly, and are characterized by the presence of hypertrophic neurons. These disorders often have a pediatric onset and a high comorbidity with drug-resistant epilepsy; however, effective pharmacological treatments are lacking. We established forebrain excitatory neuron-specific Pten-deficient cultures as an in vitro model of brain overgrowth disorders, and investigated the effects of this Pten mutation on PI3K/Akt/mTOR signaling and neuronal growth. Mutant neurons exhibit excessive PI3K/Akt/mTOR signaling activity, enlarged somas and increased dendritic arborization. To understand the contributions of Akt and mTORC1 kinases to the hypertrophy phenotype, we evaluated the effects of short-term treatment with the Akt inhibitor MK-2206, and the mTORC1 inhibitor RAD001, which have shown safety and efficacy in human cancer clinical trials. We found that RAD001 treatment only partially reversed the morphological abnormalities of Pten mutant neurons, whereas MK-2206 treatment completely rescued the phenotype. Interestingly, neither treatment altered the size or morphology of normal neurons. Our results suggest that Akt is a major determinant of neuronal growth, and that Akt inhibition may be an effective strategy for pharmacological intervention in brain overgrowth disorders.
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Affiliation(s)
- Ina Nikolaeva
- Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey, Piscataway, NJ, USA; Molecular Biosciences, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
| | - Tatiana M Kazdoba
- Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey, Piscataway, NJ, USA; Neuroscience, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
| | - Beth Crowell
- Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
| | - Gabriella D'Arcangelo
- Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey, Piscataway, NJ, USA.
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98
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FBXL5 Inactivation in Mouse Brain Induces Aberrant Proliferation of Neural Stem Progenitor Cells. Mol Cell Biol 2017; 37:MCB.00470-16. [PMID: 28069738 DOI: 10.1128/mcb.00470-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 01/03/2017] [Indexed: 01/05/2023] Open
Abstract
FBXL5 is the substrate recognition subunit of an SCF-type ubiquitin ligase that serves as a master regulator of iron metabolism in mammalian cells. We previously showed that mice with systemic deficiency of FBXL5 fail to sense intracellular iron levels and die in utero at embryonic day 8.5 (E8.5) as a result of iron overload and subsequent oxidative stress. This early embryonic mortality has thus impeded study of the role of FBXL5 in brain development. We have now generated mice lacking FBXL5 specifically in nestin-expressing neural stem progenitor cells (NSPCs) in the brain. Unexpectedly, the mutant embryos manifested a progressive increase in the number of NSPCs and astroglia in the cerebral cortex. Stabilization of iron regulatory protein 2 (IRP2) as a result of FBXL5 deficiency led to accumulation of ferrous and ferric iron as well as to generation of reactive oxygen species. Pharmacological manipulation suggested that the phenotypes of FBXL5 deficiency are attributable to aberrant activation of mammalian target of rapamycin (mTOR) signaling. Our results thus show that FBXL5 contributes to regulation of NSPC proliferation during mammalian brain development.
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99
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Bridges CR, Tan MC, Premarathne S, Nanayakkara D, Bellette B, Zencak D, Domingo D, Gecz J, Murtaza M, Jolly LA, Wood SA. USP9X deubiquitylating enzyme maintains RAPTOR protein levels, mTORC1 signalling and proliferation in neural progenitors. Sci Rep 2017; 7:391. [PMID: 28341829 PMCID: PMC5427856 DOI: 10.1038/s41598-017-00149-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 02/13/2017] [Indexed: 12/27/2022] Open
Abstract
USP9X, is highly expressed in neural progenitors and, essential for neural development in mice. In humans, mutations in USP9X are associated with neurodevelopmental disorders. To understand USP9X’s role in neural progenitors, we studied the effects of altering its expression in both the human neural progenitor cell line, ReNcell VM, as well as neural stem and progenitor cells derived from Nestin-cre conditionally deleted Usp9x mice. Decreasing USP9X resulted in ReNcell VM cells arresting in G0 cell cycle phase, with a concomitant decrease in mTORC1 signalling, a major regulator of G0/G1 cell cycle progression. Decreased mTORC1 signalling was also observed in Usp9x-null neurospheres and embryonic mouse brains. Further analyses revealed, (i) the canonical mTORC1 protein, RAPTOR, physically associates with Usp9x in embryonic brains, (ii) RAPTOR protein level is directly proportional to USP9X, in both loss- and gain-of-function experiments in cultured cells and, (iii) USP9X deubiquitlyating activity opposes the proteasomal degradation of RAPTOR. EdU incorporation assays confirmed Usp9x maintains the proliferation of neural progenitors similar to Raptor-null and rapamycin-treated neurospheres. Interestingly, loss of Usp9x increased the number of sphere-forming cells consistent with enhanced neural stem cell self-renewal. To our knowledge, USP9X is the first deubiquitylating enzyme shown to stabilize RAPTOR.
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Affiliation(s)
- Caitlin R Bridges
- Eskitis Institute for Drug Discovery, Griffith University, Brisbane, Queensland, Australia
| | - Men-Chee Tan
- Eskitis Institute for Drug Discovery, Griffith University, Brisbane, Queensland, Australia
| | - Susitha Premarathne
- Eskitis Institute for Drug Discovery, Griffith University, Brisbane, Queensland, Australia
| | - Devathri Nanayakkara
- Eskitis Institute for Drug Discovery, Griffith University, Brisbane, Queensland, Australia
| | - Bernadette Bellette
- Eskitis Institute for Drug Discovery, Griffith University, Brisbane, Queensland, Australia
| | - Dusan Zencak
- Eskitis Institute for Drug Discovery, Griffith University, Brisbane, Queensland, Australia
| | - Deepti Domingo
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia
| | - Jozef Gecz
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia.,Robinson Institute, School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, South Australia, Australia
| | - Mariyam Murtaza
- Eskitis Institute for Drug Discovery, Griffith University, Brisbane, Queensland, Australia
| | - Lachlan A Jolly
- Robinson Institute, School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, South Australia, Australia.
| | - Stephen A Wood
- Eskitis Institute for Drug Discovery, Griffith University, Brisbane, Queensland, Australia.
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100
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Li Y, Cao J, Chen M, Li J, Sun Y, Zhang Y, Zhu Y, Wang L, Zhang C. Abnormal Neural Progenitor Cells Differentiated from Induced Pluripotent Stem Cells Partially Mimicked Development of TSC2 Neurological Abnormalities. Stem Cell Reports 2017; 8:883-893. [PMID: 28344003 PMCID: PMC5390135 DOI: 10.1016/j.stemcr.2017.02.020] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 02/22/2017] [Accepted: 02/23/2017] [Indexed: 12/31/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a disease featuring devastating and therapeutically challenging neurological abnormalities. However, there is a lack of specific neural progenitor cell models for TSC. Here, the pathology of TSC was studied using primitive neural stem cells (pNSCs) from a patient presenting a c.1444-2A>C mutation in TSC2. We found that TSC2 pNSCs had higher proliferative activity and increased PAX6 expression compared with those of control pNSCs. Neurons differentiated from TSC2 pNSCs showed enlargement of the soma, perturbed neurite outgrowth, and abnormal connections among cells. TSC2 astrocytes had increased saturation density and higher proliferative activity. Moreover, the activity of the mTOR pathway was enhanced in pNSCs and induced in neurons and astrocytes. Thus, our results suggested that TSC2 heterozygosity caused neurological malformations in pNSCs, indicating that its heterozygosity might be sufficient for the development of neurological abnormalities in patients.
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Affiliation(s)
- Yaqin Li
- Department of Neurology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China; Department of Neurology, Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, Guangdong 518017, P.R. China
| | - Jiqing Cao
- Department of Neurology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China; Department of Neurology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430014, P.R. China
| | - Menglong Chen
- Department of Neurology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Jing Li
- Department of Neurology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Yiming Sun
- Department of Neurology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Yu Zhang
- Department of Neurology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Yuling Zhu
- Department of Neurology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Liang Wang
- Department of Neurology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Cheng Zhang
- Department of Neurology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China.
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