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Zhuang K, Leng L, Su X, Wang S, Su Y, Chen Y, Yuan Z, Zi L, Li J, Xie W, Yan S, Xia Y, Wang H, Li H, Chen Z, Yuan T, Zhang J. Menin Deficiency Induces Autism-Like Behaviors by Regulating Foxg1 Transcription and Participates in Foxg1-Related Encephalopathy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2307953. [PMID: 38582517 DOI: 10.1002/advs.202307953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 03/18/2024] [Indexed: 04/08/2024]
Abstract
FOXG1 syndrome is a developmental encephalopathy caused by FOXG1 (Forkhead box G1) mutations, resulting in high phenotypic variability. However, the upstream transcriptional regulation of Foxg1 expression remains unclear. This report demonstrates that both deficiency and overexpression of Men1 (protein: menin, a pathogenic gene of MEN1 syndrome known as multiple endocrine neoplasia type 1) lead to autism-like behaviors, such as social defects, increased repetitive behaviors, and cognitive impairments. Multifaceted transcriptome analyses revealed that Foxg1 signaling is predominantly altered in Men1 deficiency mice, through its regulation of the Alpha Thalassemia/Mental Retardation Syndrome X-Linked (Atrx) factor. Atrx recruits menin to bind to the transcriptional start region of Foxg1 and mediates the regulation of Foxg1 expression by H3K4me3 (Trimethylation of histone H3 lysine 4) modification. The deficits observed in menin deficient mice are rescued by the over-expression of Foxg1, leading to normalized spine growth and restoration of hippocampal synaptic plasticity. These findings suggest that menin may have a putative role in the maintenance of Foxg1 expression, highlighting menin signaling as a potential therapeutic target for Foxg1-related encephalopathy.
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Affiliation(s)
- Kai Zhuang
- Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361105, China
| | - Lige Leng
- Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361105, China
| | - Xiao Su
- Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361105, China
| | - Shuzhong Wang
- Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361105, China
| | - Yuemin Su
- Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361105, China
| | - Yanbing Chen
- Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361105, China
| | - Ziqi Yuan
- Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361105, China
| | - Liu Zi
- Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361105, China
| | - Jieyin Li
- Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361105, China
| | - Wenting Xie
- Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361105, China
| | - Sihan Yan
- Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361105, China
| | - Yujun Xia
- Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361105, China
| | - Han Wang
- Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361105, China
| | - Huifang Li
- Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361105, China
| | - Zhenyi Chen
- Department of Anesthesiology, First Affiliated Hospital, College of Medicine, Xiamen University, Xiamen, Fujian, 361105, China
| | - Tifei Yuan
- Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai, 200030, China
| | - Jie Zhang
- Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361105, China
- Department of Anesthesiology, First Affiliated Hospital, College of Medicine, Xiamen University, Xiamen, Fujian, 361105, China
- The Key Laboratory of Neural and Vascular Biology, Ministry of Education, College of Basic Medicine, Hebei Medical University, Shijiazhuang, 050017, China
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Xiao W, Li P, Kong F, Kong J, Pan A, Long L, Yan X, Xiao B, Gong J, Wan L. Unraveling the Neural Circuits: Techniques, Opportunities and Challenges in Epilepsy Research. Cell Mol Neurobiol 2024; 44:27. [PMID: 38443733 PMCID: PMC10914928 DOI: 10.1007/s10571-024-01458-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Accepted: 01/24/2024] [Indexed: 03/07/2024]
Abstract
Epilepsy, a prevalent neurological disorder characterized by high morbidity, frequent recurrence, and potential drug resistance, profoundly affects millions of people globally. Understanding the microscopic mechanisms underlying seizures is crucial for effective epilepsy treatment, and a thorough understanding of the intricate neural circuits underlying epilepsy is vital for the development of targeted therapies and the enhancement of clinical outcomes. This review begins with an exploration of the historical evolution of techniques used in studying neural circuits related to epilepsy. It then provides an extensive overview of diverse techniques employed in this domain, discussing their fundamental principles, strengths, limitations, as well as their application. Additionally, the synthesis of multiple techniques to unveil the complexity of neural circuits is summarized. Finally, this review also presents targeted drug therapies associated with epileptic neural circuits. By providing a critical assessment of methodologies used in the study of epileptic neural circuits, this review seeks to enhance the understanding of these techniques, stimulate innovative approaches for unraveling epilepsy's complexities, and ultimately facilitate improved treatment and clinical translation for epilepsy.
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Affiliation(s)
- Wenjie Xiao
- Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, Hunan Province, China
| | - Peile Li
- Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, Hunan Province, China
| | - Fujiao Kong
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
| | - Jingyi Kong
- Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, Hunan Province, China
| | - Aihua Pan
- Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, Hunan Province, China
| | - Lili Long
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Xiaoxin Yan
- Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, Hunan Province, China
| | - Bo Xiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Jiaoe Gong
- Department of Neurology, Hunan Children's Hospital, Changsha, Hunan Province, China.
| | - Lily Wan
- Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, Hunan Province, China.
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Abstract
Rett syndrome is a neurodevelopmental disorder caused by loss-of-function mutations in the methyl-CpG binding protein-2 (MeCP2) gene that is characterized by epilepsy, intellectual disability, autistic features, speech deficits, and sleep and breathing abnormalities. Neurologically, patients with all three disorders display microcephaly, aberrant dendritic morphology, reduced spine density, and an imbalance of excitatory/inhibitory signaling. Loss-of-function mutations in the cyclin-dependent kinase-like 5 (CDKL5) and FOXG1 genes also cause similar behavioral and neurobiological defects and were referred to as congenital or variant Rett syndrome. The relatively recent realization that CDKL5 deficiency disorder (CDD), FOXG1 syndrome, and Rett syndrome are distinct neurodevelopmental disorders with some distinctive features have resulted in separate focus being placed on each disorder with the assumption that distinct molecular mechanisms underlie their pathogenesis. However, given that many of the core symptoms and neurological features are shared, it is likely that the disorders share some critical molecular underpinnings. This review discusses the possibility that deregulation of common molecules in neurons and astrocytes plays a central role in key behavioral and neurological abnormalities in all three disorders. These include KCC2, a chloride transporter, vGlut1, a vesicular glutamate transporter, GluD1, an orphan-glutamate receptor subunit, and PSD-95, a postsynaptic scaffolding protein. We propose that reduced expression or activity of KCC2, vGlut1, PSD-95, and AKT, along with increased expression of GluD1, is involved in the excitatory/inhibitory that represents a key aspect in all three disorders. In addition, astrocyte-derived brain-derived neurotrophic factor (BDNF), insulin-like growth factor 1 (IGF-1), and inflammatory cytokines likely affect the expression and functioning of these molecules resulting in disease-associated abnormalities.
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Affiliation(s)
- Santosh R D’Mello
- Department of Biological Sciences, Louisiana State University Shreveport, Shreveport, LA 71104, USA
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Multimodal epigenetic changes and altered NEUROD1 chromatin binding in the mouse hippocampus underlie FOXG1 syndrome. Proc Natl Acad Sci U S A 2023; 120:e2122467120. [PMID: 36598943 PMCID: PMC9926245 DOI: 10.1073/pnas.2122467120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Forkhead box G1 (FOXG1) has important functions in neuronal differentiation and balances excitatory/inhibitory network activity. Thus far, molecular processes underlying FOXG1 function are largely unexplored. Here, we present a multiomics data set exploring how FOXG1 impacts neuronal maturation at the chromatin level in the mouse hippocampus. At a genome-wide level, FOXG1 i) both represses and activates transcription, ii) binds mainly to enhancer regions, iii) reconfigures the epigenetic landscape through bidirectional alteration of H3K27ac, H3K4me3, and chromatin accessibility, and iv) operates synergistically with NEUROD1. Interestingly, we could not detect a clear hierarchy of FOXG1 and NEUROD1, but instead, provide the evidence that they act in a highly cooperative manner to control neuronal maturation. Genes affected by the chromatin alterations impact synaptogenesis and axonogenesis. Inhibition of histone deacetylases partially rescues transcriptional alterations upon FOXG1 reduction. This integrated multiomics view of changes upon FOXG1 reduction reveals an unprecedented multimodality of FOXG1 functions converging on neuronal maturation. It fuels therapeutic options based on epigenetic drugs to alleviate, at least in part, neuronal dysfunction.
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Epigenetic genes and epilepsy - emerging mechanisms and clinical applications. Nat Rev Neurol 2022; 18:530-543. [PMID: 35859062 DOI: 10.1038/s41582-022-00693-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/16/2022] [Indexed: 12/21/2022]
Abstract
An increasing number of epilepsies are being attributed to variants in genes with epigenetic functions. The products of these genes include factors that regulate the structure and function of chromatin and the placing, reading and removal of epigenetic marks, as well as other epigenetic processes. In this Review, we provide an overview of the various epigenetic processes, structuring our discussion around five function-based categories: DNA methylation, histone modifications, histone-DNA crosstalk, non-coding RNAs and chromatin remodelling. We provide background information on each category, describing the general mechanism by which each process leads to altered gene expression. We also highlight key clinical and mechanistic aspects, providing examples of genes that strongly associate with epilepsy within each class. We consider the practical applications of these findings, including tissue-based and biofluid-based diagnostics and precision medicine-based treatments. We conclude that variants in epigenetic genes are increasingly found to be causally involved in the epilepsies, with implications for disease mechanisms, treatments and diagnostics.
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Akol I, Gather F, Vogel T. Paving Therapeutic Avenues for FOXG1 Syndrome: Untangling Genotypes and Phenotypes from a Molecular Perspective. Int J Mol Sci 2022; 23:ijms23020954. [PMID: 35055139 PMCID: PMC8780739 DOI: 10.3390/ijms23020954] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/23/2021] [Accepted: 01/13/2022] [Indexed: 02/01/2023] Open
Abstract
Development of the central nervous system (CNS) depends on accurate spatiotemporal control of signaling pathways and transcriptional programs. Forkhead Box G1 (FOXG1) is one of the master regulators that play fundamental roles in forebrain development; from the timing of neurogenesis, to the patterning of the cerebral cortex. Mutations in the FOXG1 gene cause a rare neurodevelopmental disorder called FOXG1 syndrome, also known as congenital form of Rett syndrome. Patients presenting with FOXG1 syndrome manifest a spectrum of phenotypes, ranging from severe cognitive dysfunction and microcephaly to social withdrawal and communication deficits, with varying severities. To develop and improve therapeutic interventions, there has been considerable progress towards unravelling the multi-faceted functions of FOXG1 in the neurodevelopment and pathogenesis of FOXG1 syndrome. Moreover, recent advances in genome editing and stem cell technologies, as well as the increased yield of information from high throughput omics, have opened promising and important new avenues in FOXG1 research. In this review, we provide a summary of the clinical features and emerging molecular mechanisms underlying FOXG1 syndrome, and explore disease-modelling approaches in animals and human-based systems, to highlight the prospects of research and possible clinical interventions.
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Affiliation(s)
- Ipek Akol
- Department of Molecular Embryology, Institute for Anatomy and Cell Biology, Medical Faculty, University of Freiburg, 79104 Freiburg, Germany; (I.A.); (F.G.)
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
- Center for Basics in NeuroModulation (NeuroModul Basics), Medical Faculty, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Fabian Gather
- Department of Molecular Embryology, Institute for Anatomy and Cell Biology, Medical Faculty, University of Freiburg, 79104 Freiburg, Germany; (I.A.); (F.G.)
| | - Tanja Vogel
- Department of Molecular Embryology, Institute for Anatomy and Cell Biology, Medical Faculty, University of Freiburg, 79104 Freiburg, Germany; (I.A.); (F.G.)
- Center for Basics in NeuroModulation (NeuroModul Basics), Medical Faculty, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
- Correspondence:
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Scabia G, Testa G, Scali M, Del Turco S, Desiato G, Berardi N, Sale A, Matteoli M, Maffei L, Maffei M, Mainardi M. Reduced ccl11/eotaxin mediates the beneficial effects of environmental stimulation on the aged hippocampus. Brain Behav Immun 2021; 98:234-244. [PMID: 34418501 DOI: 10.1016/j.bbi.2021.08.222] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 07/15/2021] [Accepted: 08/13/2021] [Indexed: 02/08/2023] Open
Abstract
A deterioration in cognitive performance accompanies brain aging, even in the absence of neurodegenerative pathologies. However, the rate of cognitive decline can be slowed down by enhanced cognitive and sensorimotor stimulation protocols, such as environmental enrichment (EE). Understanding how EE exerts its beneficial effects on the aged brain pathophysiology can help in identifying new therapeutic targets. In this regard, the inflammatory chemokine ccl11/eotaxin-1 is a marker of aging with a strong relevance for neurodegenerative processes. Here, we demonstrate that EE in both elderly humans and aged mice decreases circulating levels of ccl11. Interfering, in mice, with the ccl11 decrease induced by EE ablated the beneficial effects on long-term memory retention, hippocampal neurogenesis, activation of local microglia and of ribosomal protein S6. On the other hand, treatment of standard-reared aged mice with an anti-ccl11 antibody resulted in EE-like improvements in spatial memory, hippocampal neurogenesis, and microglial activation. Taken together, our findings point to a decrease in circulating ccl11 concentration as a key mediator of the enhanced hippocampal function resulting from exposure to EE.
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Affiliation(s)
- Gaia Scabia
- Institute of Clinical Physiology, National Research Council (IFC-CNR), Pisa, Italy; Obesity and Lipodystrophies Center at Pisa University Hospital, Pisa, Italy
| | - Giovanna Testa
- Laboratory of Biology "Bio@SNS", Scuola Normale Superiore, Pisa, Italy
| | - Manuela Scali
- Institute of Neuroscience, National Research Council (IN-CNR), Pisa, Italy
| | - Serena Del Turco
- Institute of Clinical Physiology, National Research Council (IFC-CNR), Pisa, Italy
| | - Genni Desiato
- Institute of Neuroscience, National Research Council (IN-CNR), Milan, Italy; Humanitas Clinical and Research Center - IRCCS, Rozzano, Milan, Italy
| | - Nicoletta Berardi
- Institute of Neuroscience, National Research Council (IN-CNR), Pisa, Italy; Department of Neuroscience, Psychology, Drug Research and Child Health, NEUROFARBA University of Florence, Florence, Italy
| | - Alessandro Sale
- Institute of Neuroscience, National Research Council (IN-CNR), Pisa, Italy
| | - Michela Matteoli
- Institute of Neuroscience, National Research Council (IN-CNR), Milan, Italy; Humanitas Clinical and Research Center - IRCCS, Rozzano, Milan, Italy
| | - Lamberto Maffei
- Laboratory of Biology "Bio@SNS", Scuola Normale Superiore, Pisa, Italy; Institute of Neuroscience, National Research Council (IN-CNR), Pisa, Italy
| | - Margherita Maffei
- Institute of Clinical Physiology, National Research Council (IFC-CNR), Pisa, Italy; Obesity and Lipodystrophies Center at Pisa University Hospital, Pisa, Italy.
| | - Marco Mainardi
- Laboratory of Biology "Bio@SNS", Scuola Normale Superiore, Pisa, Italy; Institute of Neuroscience, National Research Council (IN-CNR), Pisa, Italy.
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Reviewing Evidence for the Relationship of EEG Abnormalities and RTT Phenotype Paralleled by Insights from Animal Studies. Int J Mol Sci 2021; 22:ijms22105308. [PMID: 34069993 PMCID: PMC8157853 DOI: 10.3390/ijms22105308] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/09/2021] [Accepted: 05/12/2021] [Indexed: 12/29/2022] Open
Abstract
Rett syndrome (RTT) is a rare neurodevelopmental disorder that is usually caused by mutations of the MECP2 gene. Patients with RTT suffer from severe deficits in motor, perceptual and cognitive domains. Electroencephalogram (EEG) has provided useful information to clinicians and scientists, from the very first descriptions of RTT, and yet no reliable neurophysiological biomarkers related to the pathophysiology of the disorder or symptom severity have been identified to date. To identify consistently observed and potentially informative EEG characteristics of RTT pathophysiology, and ascertain areas most worthy of further systematic investigation, here we review the literature for EEG abnormalities reported in patients with RTT and in its disease models. While pointing to some promising potential EEG biomarkers of RTT, our review identify areas of need to realize the potential of EEG including (1) quantitative investigation of promising clinical-EEG observations in RTT, e.g., shift of mu rhythm frequency and EEG during sleep; (2) closer alignment of approaches between patients with RTT and its animal models to strengthen the translational significance of the work (e.g., EEG measurements and behavioral states); (3) establishment of large-scale consortium research, to provide adequate Ns to investigate age and genotype effects.
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Conti S, Spalletti C, Pasquini M, Giordano N, Barsotti N, Mainardi M, Lai S, Giorgi A, Pasqualetti M, Micera S, Caleo M. Combining robotics with enhanced serotonin-driven cortical plasticity improves post-stroke motor recovery. Prog Neurobiol 2021; 203:102073. [PMID: 33984455 DOI: 10.1016/j.pneurobio.2021.102073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 04/22/2021] [Accepted: 05/06/2021] [Indexed: 10/21/2022]
Abstract
Despite recent progresses in robotic rehabilitation technologies, their efficacy for post-stroke motor recovery is still limited. Such limitations might stem from the insufficient enhancement of plasticity mechanisms, crucial for functional recovery. Here, we designed a clinically relevant strategy that combines robotic rehabilitation with chemogenetic stimulation of serotonin release to boost plasticity. These two approaches acted synergistically to enhance post-stroke motor performance. Indeed, mice treated with our combined therapy showed substantial functional gains that persisted beyond the treatment period and generalized to non-trained tasks. Motor recovery was associated with a reduction in electrophysiological and neuroanatomical markers of GABAergic neurotransmission, suggesting disinhibition in perilesional areas. To unveil the translational potentialities of our approach, we specifically targeted the serotonin 1A receptor by delivering Buspirone, a clinically approved drug, in stroke mice undergoing robotic rehabilitation. Administration of Buspirone restored motor impairments similarly to what observed with chemogenetic stimulation, showing the immediate translational potential of this combined approach to significantly improve motor recovery after stroke.
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Affiliation(s)
- S Conti
- Translational Neural Engineering Area, The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - C Spalletti
- Institute of Neuroscience, National Research Council (CNR), Pisa, Italy
| | - M Pasquini
- Translational Neural Engineering Area, The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - N Giordano
- Institute of Neuroscience, National Research Council (CNR), Pisa, Italy
| | - N Barsotti
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, Italy
| | - M Mainardi
- Institute of Neuroscience, National Research Council (CNR), Pisa, Italy
| | - S Lai
- Translational Neural Engineering Area, The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - A Giorgi
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, Italy
| | - M Pasqualetti
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, Italy; Center for Neuroscience and Cognitive Systems, Istituto Italiano di Tecnologia, Rovereto, Italy
| | - S Micera
- Translational Neural Engineering Area, The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy; Bertarelli Foundation Chair in Translational NeuroEngineering Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), Centre for Neuroprosthetics and Institute of Bioengineering, Lausanne, Switzerland.
| | - M Caleo
- Institute of Neuroscience, National Research Council (CNR), Pisa, Italy; Department of Biomedical Sciences, University of Padova, Italy.
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Ding Y, Meng W, Kong W, He Z, Chai R. The Role of FoxG1 in the Inner Ear. Front Cell Dev Biol 2020; 8:614954. [PMID: 33344461 PMCID: PMC7744801 DOI: 10.3389/fcell.2020.614954] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 11/18/2020] [Indexed: 12/12/2022] Open
Abstract
Sensorineural deafness is mainly caused by damage to the tissues of the inner ear, and hearing impairment has become an increasingly serious global health problem. When the inner ear is abnormally developed or is damaged by inflammation, ototoxic drugs, or blood supply disorders, auditory signal transmission is inhibited resulting in hearing loss. Forkhead box G1 (FoxG1) is an important nuclear transcriptional regulator, which is related to the differentiation, proliferation, development, and survival of cells in the brain, telencephalon, inner ear, and other tissues. Previous studies have shown that when FoxG1 is abnormally expressed, the development and function of inner ear hair cells is impaired. This review discusses the role and regulatory mechanism of FoxG1 in inner ear tissue from various aspects – such as the effect on inner ear development, the maintenance of inner ear structure and function, and its role in the inner ear when subjected to various stimulations or injuries – in order to explain the potential significance of FoxG1 as a new target for the treatment of hearing loss.
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Affiliation(s)
- Yanyan Ding
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wei Meng
- Department of Otolaryngology Head and Neck, Nanjing Tongren Hospital, School of Medicine, Southeast University, Nanjing, China
| | - Weijia Kong
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zuhong He
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Renjie Chai
- State Key Laboratory of Bioelectronics, School of Life Sciences and Technology, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China.,Institute of Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China.,Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
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11
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Sabetghadam A, Wu C, Liu J, Zhang L, Reid AY. Increased epileptogenicity in a mouse model of neurofibromatosis type 1. Exp Neurol 2020; 331:113373. [PMID: 32502580 DOI: 10.1016/j.expneurol.2020.113373] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 05/22/2020] [Accepted: 06/01/2020] [Indexed: 11/19/2022]
Abstract
RATIONALE Neurofibromatosis type 1 (NF1) is associated with higher rates of epilepsy compared to the general population. Some NF1 patients with epilepsy do not have intracranial lesions, suggesting the genetic mutation itself may contribute to higher rates of epilepsy in these patients. We have recently demonstrated increased seizure susceptibility in the Nf1+/- mouse, but it is unknown whether this model displays altered epileptogenicity, as has been reported in patients with NF1. The aim of this study was to determine whether the Nf1+/- mouse is more susceptible to electrical kindling-induced epileptogenesis. METHODS Young male or female adult Nf1+/- or Nf1+/+ (wild-type; WT) mice were implanted with electrodes for neocortical or hippocampal kindling paradigms. Neocortical kindling was performed for 40 stimulation sessions followed by baseline EEG monitoring to detect possible SRSs. Hippocampal kindling was performed with a modified extended kindling paradigm, completed to a maximum of 80 sessions to try to induce spontaneous repetitive seizures (SRSs). Western blot assays were performed in naïve and kindled mice to compare levels of Akt and MAPK (ERK1/2), proteins downstream of the NF1 mutation. RESULTS The average initial neocortical after-discharge threshold (ADT) was significantly lower in the Nf1+/- group, which also required fewer stimulations to reach stage 5 seizure, had greater average seizure severity across all kindling sessions, had a greater number of convulsive seizures, and had a faster progression of after-discharge duration and Racine score during kindling. No WT mice exhibited SRS after neocortical kindling, versus 33% of Nf1+/- mice. The average initial hippocampal ADT was not significantly different between the WT and Nf1+/- groups, nor was there a difference in the number of stimulations required to reach the kindled state. The WT group had a significantly higher average seizure severity across all kindling sessions as compared with the Nf1+/- mice. The WT group also had faster progression of the Racine seizure score over the kindling sessions, mainly due to a faster increase in seizures severity early during the kindling process. However, SRSs were seen in 50% of Nf1+/- mice after modified extended kindling and in no WT mice. Western blots showed hippocampal kindling increased the ratio of phosphorylated/total Akt in both the WT and Nf1+/- mice, while neocortical kindling led to increased ratios of phosphorylated/total Akt and MAPK in Nf1+/- mice only. CONCLUSIONS We have demonstrated for the first time an increased rate of epileptogenesis in an animal model of NF1 with no known macroscopic/neoplastic brain lesions. This work provides evidence for the genetic mutation itself playing a role in seizures and epilepsy in patients with NF1, and supports the use of the Nf1+/- mouse model in future mechanistic studies.
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Affiliation(s)
- A Sabetghadam
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, Ontario M5T 0S8, Canada.
| | - C Wu
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, Ontario M5T 0S8, Canada
| | - J Liu
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, Ontario M5T 0S8, Canada
| | - L Zhang
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, Ontario M5T 0S8, Canada; Department of Medicine (Neurology), University of Toronto, Toronto, Ontario, Canada
| | - A Y Reid
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, Ontario M5T 0S8, Canada; Department of Medicine (Neurology), University of Toronto, Toronto, Ontario, Canada
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12
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Extremely Low Forces Induce Extreme Axon Growth. J Neurosci 2020; 40:4997-5007. [PMID: 32444384 DOI: 10.1523/jneurosci.3075-19.2020] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 04/16/2020] [Accepted: 04/21/2020] [Indexed: 12/27/2022] Open
Abstract
Stretch-growth has been defined as a process that extends axons via the application of mechanical forces. In the present article, we used a protocol based on magnetic nanoparticles (NPs) for labeling the entire axon tract of hippocampal neurons, and an external magnetic field gradient to generate a dragging force. We found that the application of forces below 10 pN induces growth at a rate of 0.66 ± 0.02 µm h-1 pN-1 Calcium imaging confirmed the strong increase in elongation rate, in comparison with the condition of tip-growth. Enhanced growth in stretched axons was also accompanied by endoplasmic reticulum (ER) accumulation and, accordingly, it was blocked by an inhibition of translation. Stretch-growth was also found to stimulate axonal branching, glutamatergic synaptic transmission, and neuronal excitability. Moreover, stretched axons showed increased microtubule (MT) density and MT assembly was key to sustaining stretch-growth, suggesting a possible role of tensile forces in MT translocation/assembly. Additionally, our data showed that stretched axons do not respond to BDNF signaling, suggesting interference between the two pathways. As these extremely low mechanical forces are physiologically relevant, stretch-growth could be an important endogenous mechanism of axon growth, with a potential for designing novel strategies for axonal regrowth.SIGNIFICANCE STATEMENT Axon growth involves motion, and motion is driven by forces. The growth cone (GC) itself can generate very low intracellular forces by inducing a drastic cytoskeleton remodeling, in response to signaling molecules. Here, we investigated the key role of intracellular force as an endogenous regulator of axon outgrowth, which it has been neglected for decades because of the lack of methodologies to investigate the topic. Our results indicate a critical role of force in promoting axon growth by facilitating microtubule (MT) polymerization.
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Synaptic Pruning by Microglia in Epilepsy. J Clin Med 2019; 8:jcm8122170. [PMID: 31818018 PMCID: PMC6947403 DOI: 10.3390/jcm8122170] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 11/27/2019] [Accepted: 12/05/2019] [Indexed: 12/16/2022] Open
Abstract
Structural and functional collapse of the balance between excitatory (E) and inhibitory (I) synapses, i.e., synaptic E/I balance, underlies the pathogeneses of various central nervous system (CNS) disorders. In epilepsy, the synaptic E/I balance tips toward excitation; thus, most of the existing epileptic remedies have focused on how to directly suppress the activity of neurons. However, because as many as 30% of patients with epilepsy are drug resistant, the discovery of new therapeutic targets is strongly desired. Recently, the roles of glial cells in epilepsy have gained attention because glial cells manipulate synaptic structures and functions in addition to supporting neuronal survival and growth. Among glial cells, microglia, which are brain-resident immune cells, have been shown to mediate inflammation, neuronal death and aberrant neurogenesis after epileptic seizures. However, few studies have investigated the involvement of synaptic pruning—one of the most important roles of microglia—in the epileptic brain. In this review, we propose and discuss the hypothesis that synaptic pruning by microglia is enhanced in the epileptic brain, drawing upon the findings of previous studies. We further discuss the possibility that aberrant synaptic pruning by microglia induces synaptic E/I imbalance, promoting the development and aggravation of epilepsy.
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