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Khaliulin I, Hamoudi W, Amal H. The multifaceted role of mitochondria in autism spectrum disorder. Mol Psychiatry 2024:10.1038/s41380-024-02725-z. [PMID: 39223276 DOI: 10.1038/s41380-024-02725-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 08/21/2024] [Accepted: 08/23/2024] [Indexed: 09/04/2024]
Abstract
Normal brain functioning relies on high aerobic energy production provided by mitochondria. Failure to supply a sufficient amount of energy, seen in different brain disorders, including autism spectrum disorder (ASD), may have a significant negative impact on brain development and support of different brain functions. Mitochondrial dysfunction, manifested in the abnormal activities of the electron transport chain and impaired energy metabolism, greatly contributes to ASD. The aberrant functioning of this organelle is of such high importance that ASD has been proposed as a mitochondrial disease. It should be noted that aerobic energy production is not the only function of the mitochondria. In particular, these organelles are involved in the regulation of Ca2+ homeostasis, different mechanisms of programmed cell death, autophagy, and reactive oxygen and nitrogen species (ROS and RNS) production. Several syndromes originated from mitochondria-related mutations display ASD phenotype. Abnormalities in Ca2+ handling and ATP production in the brain mitochondria affect synaptic transmission, plasticity, and synaptic development, contributing to ASD. ROS and Ca2+ regulate the activity of the mitochondrial permeability transition pore (mPTP). The prolonged opening of this pore affects the redox state of the mitochondria, impairs oxidative phosphorylation, and activates apoptosis, ultimately leading to cell death. A dysregulation between the enhanced mitochondria-related processes of apoptosis and the inhibited autophagy leads to the accumulation of toxic products in the brains of individuals with ASD. Although many mitochondria-related mechanisms still have to be investigated, and whether they are the cause or consequence of this disorder is still unknown, the accumulating data show that the breakdown of any of the mitochondrial functions may contribute to abnormal brain development leading to ASD. In this review, we discuss the multifaceted role of mitochondria in ASD from the various aspects of neuroscience.
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Affiliation(s)
- Igor Khaliulin
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Wajeha Hamoudi
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Haitham Amal
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
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2
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Yamada T, Watanabe T, Sasaki Y. Are sleep disturbances a cause or consequence of autism spectrum disorder? Psychiatry Clin Neurosci 2023; 77:377-385. [PMID: 36949621 PMCID: PMC10871071 DOI: 10.1111/pcn.13550] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 03/10/2023] [Accepted: 03/17/2023] [Indexed: 03/24/2023]
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by core symptoms such as atypical social communication, stereotyped behaviors, and restricted interests. One of the comorbid symptoms of individuals with ASD is sleep disturbance. There are two major hypotheses regarding the neural mechanism underlying ASD, i.e., the excitation/inhibition (E/I) imbalance and the altered neuroplasticity hypotheses. However, the pathology of ASD remains unclear due to inconsistent research results. This paper argues that sleep is a confounding factor, thus, must be considered when examining the pathology of ASD because sleep plays an important role in modulating the E/I balance and neuroplasticity in the human brain. Investigation of the E/I balance and neuroplasticity during sleep might enhance our understanding of the neural mechanisms of ASD. It may also lead to the development of neurobiologically informed interventions to supplement existing psychosocial therapies.
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Affiliation(s)
- Takashi Yamada
- Department of Cognitive, Linguistic, and Psychological Sciences, Brown University, Providence, 02912, USA
| | - Takeo Watanabe
- Department of Cognitive, Linguistic, and Psychological Sciences, Brown University, Providence, 02912, USA
| | - Yuka Sasaki
- Department of Cognitive, Linguistic, and Psychological Sciences, Brown University, Providence, 02912, USA
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3
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Oluigbo DC. Rett Syndrome: A Tale of Altered Genetics, Synaptic Plasticity, and Neurodevelopmental Dynamics. Cureus 2023; 15:e41555. [PMID: 37554594 PMCID: PMC10405636 DOI: 10.7759/cureus.41555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2023] [Indexed: 08/10/2023] Open
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder that is a leading cause of severe cognitive and physical impairment. RTT typically occurs in females, although rare cases of males with the disease exist. Its genetic cause, symptoms, and clinical progression timeline have also become well-documented since its initial discovery. However, a relatively late diagnosis and lack of an available cure signify that our understanding of the disease is incomplete. Innovative research methods and tools are thereby helping to fill gaps in our knowledge of RTT. Specifically, mouse models of RTT, video analysis, and retrospective parental analysis are well-established tools that provide valuable insights into RTT. Moreover, current and anticipated treatment options are improving the quality of life of the RTT patient population. Collectively, these developments are creating optimistic future perspectives for RTT.
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Affiliation(s)
- David C Oluigbo
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, USA
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4
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Bae J, Ahn S, Cho DW, Kim HS, Han SC, Im HI. Claustral MeCP2 Regulates Methamphetamine-induced Conditioned Place Preference in Cynomolgus Monkey. Exp Neurobiol 2022; 31:390-400. [PMID: 36631847 PMCID: PMC9841746 DOI: 10.5607/en22034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/17/2022] [Accepted: 11/28/2022] [Indexed: 01/13/2023] Open
Abstract
The claustrum, a brain nucleus located between the cortex and the striatum, has recently been highlighted in drug-related reward processing. Methyl CpG-binding protein-2 (MeCP2) is a transcriptional regulator that represses or activates the expression of the target gene and has been known to have an important role in the regulation of drug addiction in the dopaminergic reward system. The claustrum is an important region for regulating reward processing where most neurons receive dopamine input; additionally, in this region, MeCP2 is also abundantly expressed. Therefore, here, we hypothesized that MeCP2 would be involved in drug addiction control in the Claustrum as well and investigated how claustral MeCP2 regulates drug addiction. To better understand the function of human claustral MeCP2, we established a non-human primate model of methamphetamine (METH) - induced conditioned place preference (CPP). After a habituation of two days and conditioning of ten days, the CPP test was conducted for three days. Interestingly, we confirmed that virus-mediated overexpression of MECP2 in the claustrum showed a significant reduction of METH-induced CPP in the three consecutive days during the testing period. Moreover, they showed a decrease in visit scores (frequency for visit) for the METH-paired room compared to the control group although the scores were statistically marginal. Taken together, we suggest that the claustrum is an important brain region associated with drug addiction, in which MeCP2 may function as a mediator in regulating the response to addictive drugs.
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Affiliation(s)
- Jinhee Bae
- Center for Brain Function, Brain Science Institute, Korea Institute of Science and Technology, Seoul 02792, Korea
| | - Sujin Ahn
- Center for Brain Function, Brain Science Institute, Korea Institute of Science and Technology, Seoul 02792, Korea
| | - Doo-Wan Cho
- Jeonbuk Branch Institute, Korea Institute of Toxicology, Jeongeup 56212, Korea
| | - Hyung-Sun Kim
- Jeonbuk Branch Institute, Korea Institute of Toxicology, Jeongeup 56212, Korea
| | - Su-Cheol Han
- Jeonbuk Branch Institute, Korea Institute of Toxicology, Jeongeup 56212, Korea
| | - Heh-In Im
- Center for Brain Function, Brain Science Institute, Korea Institute of Science and Technology, Seoul 02792, Korea,Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea,To whom correspondence should be addressed. TEL: 82-2-958-6961, FAX: 82-2-958-6937, e-mail:
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5
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Oláh VJ, Pedersen NP, Rowan MJM. Ultrafast simulation of large-scale neocortical microcircuitry with biophysically realistic neurons. eLife 2022; 11:e79535. [PMID: 36341568 PMCID: PMC9640191 DOI: 10.7554/elife.79535] [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: 04/16/2022] [Accepted: 10/23/2022] [Indexed: 11/09/2022] Open
Abstract
Understanding the activity of the mammalian brain requires an integrative knowledge of circuits at distinct scales, ranging from ion channel gating to circuit connectomics. Computational models are regularly employed to understand how multiple parameters contribute synergistically to circuit behavior. However, traditional models of anatomically and biophysically realistic neurons are computationally demanding, especially when scaled to model local circuits. To overcome this limitation, we trained several artificial neural network (ANN) architectures to model the activity of realistic multicompartmental cortical neurons. We identified an ANN architecture that accurately predicted subthreshold activity and action potential firing. The ANN could correctly generalize to previously unobserved synaptic input, including in models containing nonlinear dendritic properties. When scaled, processing times were orders of magnitude faster compared with traditional approaches, allowing for rapid parameter-space mapping in a circuit model of Rett syndrome. Thus, we present a novel ANN approach allowing for rapid, detailed network experiments using inexpensive and commonly available computational resources.
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Affiliation(s)
- Viktor J Oláh
- Department of Cell Biology, Emory University School of MedicineAtlantaUnited States
| | - Nigel P Pedersen
- Department of Neurology, Emory University School of MedicineAtlantaUnited States
| | - Matthew JM Rowan
- Department of Cell Biology, Emory University School of MedicineAtlantaUnited States
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6
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Mok RSF, Zhang W, Sheikh TI, Pradeepan K, Fernandes IR, DeJong LC, Benigno G, Hildebrandt MR, Mufteev M, Rodrigues DC, Wei W, Piekna A, Liu J, Muotri AR, Vincent JB, Muller L, Martinez-Trujillo J, Salter MW, Ellis J. Wide spectrum of neuronal and network phenotypes in human stem cell-derived excitatory neurons with Rett syndrome-associated MECP2 mutations. Transl Psychiatry 2022; 12:450. [PMID: 36253345 PMCID: PMC9576700 DOI: 10.1038/s41398-022-02216-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/01/2022] [Accepted: 10/03/2022] [Indexed: 11/19/2022] Open
Abstract
Rett syndrome (RTT) is a severe neurodevelopmental disorder primarily caused by heterozygous loss-of-function mutations in the X-linked gene MECP2 that is a global transcriptional regulator. Mutations in the methyl-CpG binding domain (MBD) of MECP2 disrupt its interaction with methylated DNA. Here, we investigate the effect of a novel MECP2 L124W missense mutation in the MBD of an atypical RTT patient with preserved speech in comparison to severe MECP2 null mutations. L124W protein had a limited ability to disrupt heterochromatic chromocenters due to decreased binding dynamics. We isolated two pairs of isogenic WT and L124W induced pluripotent stem cells. L124W induced excitatory neurons expressed stable protein, exhibited increased input resistance and decreased voltage-gated Na+ and K+ currents, and their neuronal dysmorphology was limited to decreased dendritic complexity. Three isogenic pairs of MECP2 null neurons had the expected more extreme morphological and electrophysiological phenotypes. We examined development and maturation of L124W and MECP2 null excitatory neural network activity using micro-electrode arrays. Relative to isogenic controls, L124W neurons had an increase in synchronous network burst frequency, in contrast to MECP2 null neurons that suffered a significant decrease in synchronous network burst frequency and a transient extension of network burst duration. A biologically motivated computational neural network model shows the observed changes in network dynamics are explained by changes in intrinsic Na+ and K+ currents in individual neurons. Our multilevel results demonstrate that RTT excitatory neurons show a wide spectrum of morphological, electrophysiological and circuitry phenotypes that are dependent on the severity of the MECP2 mutation.
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Grants
- R01 MH108528 NIMH NIH HHS
- MOP-133423 CIHR
- R01 MH109885 NIMH NIH HHS
- FDN-154336 CIHR
- R01 MH100175 NIMH NIH HHS
- Col Harland Sanders Rett Syndrome Research Fund at the University of Toronto (to J.E.), SFARI (Research grant #514918 to J.E. and J.M-T), CIHR (MOP-133423 to J.E. and M.W.S.; ERARE Team Grant ERT161303 to J.E.), CIHR foundation grant (FDN-154336 to M.W.S), Ontario Brain Institute (POND Network to J.E.), McLaughlin Centre Accelerator grant (to J.E.), John Evans Leadership Fund & Ontario Research Fund (to J.E), Canada Research Chair in Stem Cell Models of Childhood Disease (to J.E.), Beta Sigma Phi International Endowment Fund (to J.E.).
- BrainsCAN at Western University through the Canada First Research Excellence Fund (CFREF) (to GB, KP, LM, JMT). NSERC Postgraduate Scholarship–Doctoral (PGS-D) Scholarship to KP.
- Trainee support was provided by Restracomp (to LCD).
- National Institutes of Health (NIH) grants # R01MH108528, R01MH109885, and R01MH1000175 to ARM.
- Ontario Rett Syndrome Association to JBV.
- SFARI (Research grant #514918 to J.E. and J.M-T), BrainsCAN at Western University through the Canada First Research Excellence Fund (CFREF) (to GB, KP, LM, JMT)
- CIHR (MOP-133423 to J.E. and M.W.S.; CIHR foundation grant (FDN-154336 to M.W.S),
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Affiliation(s)
- Rebecca S F Mok
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
- Developmental & Stem Cell Biology Program, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
| | - Wenbo Zhang
- Neurosciences & Mental Health Program, The Hospital for Sick Children, Toronto, M5G 0A4, ON, Canada
| | - Taimoor I Sheikh
- Molecular Neuropsychiatry & Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, M5T 1R8, Canada
| | - Kartik Pradeepan
- Department of Physiology and Pharmacology, Department of Psychiatry, Neuroscience Graduate Program, Robarts Research and Brain and Mind Institutes, Schulich School of Medicine and Dentistry, Western University, London, ON, N6A 5B7, Canada
| | - Isabella R Fernandes
- University of California San Diego, School of Medicine, Department of Pediatrics/Rady Children's Hospital San Diego, Department of Cellular & Molecular Medicine, Stem Cell Program, La Jolla, CA, 92037-0695, USA
| | - Leah C DeJong
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
- Developmental & Stem Cell Biology Program, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
| | - Gabriel Benigno
- Department of Applied Mathematics, Robarts Research Institute, Brain and Mind Institute, Western University, London, ON, N6A 5B7, Canada
| | - Matthew R Hildebrandt
- Developmental & Stem Cell Biology Program, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
| | - Marat Mufteev
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
- Developmental & Stem Cell Biology Program, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
| | - Deivid C Rodrigues
- Developmental & Stem Cell Biology Program, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
| | - Wei Wei
- Developmental & Stem Cell Biology Program, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
| | - Alina Piekna
- Developmental & Stem Cell Biology Program, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
| | - Jiajie Liu
- Developmental & Stem Cell Biology Program, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
| | - Alysson R Muotri
- University of California San Diego, School of Medicine, Department of Pediatrics/Rady Children's Hospital San Diego, Department of Cellular & Molecular Medicine, Stem Cell Program, La Jolla, CA, 92037-0695, USA
- Department of Pediatrics/Rady Children's Hospital, Department of Cellular & Molecular Medicine, Center for Academic Research and Training in Anthropogeny, Archealization Center, Kavli Institute, University of California San Diego, La Jolla, CA, 92037, USA
| | - John B Vincent
- Molecular Neuropsychiatry & Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, M5T 1R8, Canada
| | - Lyle Muller
- Department of Applied Mathematics, Robarts Research Institute, Brain and Mind Institute, Western University, London, ON, N6A 5B7, Canada
| | - Julio Martinez-Trujillo
- Department of Physiology and Pharmacology, Department of Psychiatry, Neuroscience Graduate Program, Robarts Research and Brain and Mind Institutes, Schulich School of Medicine and Dentistry, Western University, London, ON, N6A 5B7, Canada
| | - Michael W Salter
- Neurosciences & Mental Health Program, The Hospital for Sick Children, Toronto, M5G 0A4, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - James Ellis
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.
- Developmental & Stem Cell Biology Program, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada.
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7
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Horvath PM, Piazza MK, Kavalali ET, Monteggia LM. MeCP2 loss-of-function dysregulates microRNAs regionally and disrupts excitatory/inhibitory synaptic transmission balance. Hippocampus 2022; 32:610-623. [PMID: 35851733 PMCID: PMC9344394 DOI: 10.1002/hipo.23455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 06/11/2022] [Accepted: 06/25/2022] [Indexed: 11/06/2022]
Abstract
Rett syndrome is a leading cause of intellectual disability in females primarily caused by loss of function mutations in the transcriptional regulator MeCP2. Loss of MeCP2 leads to a host of synaptic phenotypes that are believed to underlie Rett syndrome pathophysiology. Synaptic deficits vary by brain region upon MeCP2 loss, suggesting distinct molecular alterations leading to disparate synaptic outcomes. In this study, we examined the contribution of MeCP2's newly described role in miRNA regulation to regional molecular and synaptic impairments. Two miRNAs, miR-101a and miR-203, were identified and confirmed as upregulated in MeCP2 KO mice in the hippocampus and cortex, respectively. miR-101a overexpression in hippocampal cultures led to opposing effects at excitatory and inhibitory synapses and in spontaneous and evoked neurotransmission, revealing the potential for a single miRNA to broadly regulate synapse function in the hippocampus. These results highlight the importance of regional alterations in miRNA expression and the specific impact on synaptic function with potential implications for Rett syndrome.
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Affiliation(s)
- Patricia M. Horvath
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA,Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Michelle K. Piazza
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA,Neuroscience Program, Vanderbilt University, Nashville, Tennessee, USA
| | - Ege T. Kavalali
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA,Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA
| | - Lisa M. Monteggia
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA,Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA
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8
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Sánchez-Lafuente CL, Kalynchuk LE, Caruncho HJ, Ausió J. The Role of MeCP2 in Regulating Synaptic Plasticity in the Context of Stress and Depression. Cells 2022; 11:cells11040748. [PMID: 35203405 PMCID: PMC8870391 DOI: 10.3390/cells11040748] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/10/2022] [Accepted: 02/16/2022] [Indexed: 02/06/2023] Open
Abstract
Methyl-CpG-binding protein 2 (MeCP2) is a transcriptional regulator that is highly abundant in the brain. It binds to methylated genomic DNA to regulate a range of physiological functions implicated in neuronal development and adult synaptic plasticity. MeCP2 has mainly been studied for its role in neurodevelopmental disorders, but alterations in MeCP2 are also present in stress-related disorders such as major depression. Impairments in both stress regulation and synaptic plasticity are associated with depression, but the specific mechanisms underlying these changes have not been identified. Here, we review the interplay between stress, synaptic plasticity, and MeCP2. We focus our attention on the transcriptional regulation of important neuronal plasticity genes such as BDNF and reelin (RELN). Moreover, we provide evidence from recent studies showing a link between chronic stress-induced depressive symptoms and dysregulation of MeCP2 expression, underscoring the role of this protein in stress-related pathology. We conclude that MeCP2 is a promising target for the development of novel, more efficacious therapeutics for the treatment of stress-related disorders such as depression.
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Affiliation(s)
- Carla L. Sánchez-Lafuente
- Division of Medical Sciences, University of Victoria, Victoria, BC V8W 2Y2, Canada; (C.L.S.-L.); (L.E.K.); (H.J.C.)
| | - Lisa E. Kalynchuk
- Division of Medical Sciences, University of Victoria, Victoria, BC V8W 2Y2, Canada; (C.L.S.-L.); (L.E.K.); (H.J.C.)
| | - Hector J. Caruncho
- Division of Medical Sciences, University of Victoria, Victoria, BC V8W 2Y2, Canada; (C.L.S.-L.); (L.E.K.); (H.J.C.)
| | - Juan Ausió
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 3P6, Canada
- Correspondence:
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9
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Li W. Excitation and Inhibition Imbalance in Rett Syndrome. Front Neurosci 2022; 16:825063. [PMID: 35250460 PMCID: PMC8894599 DOI: 10.3389/fnins.2022.825063] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 01/31/2022] [Indexed: 12/12/2022] Open
Abstract
A loss of the excitation/inhibition (E/I) balance in the neural circuit has emerged as a common neuropathological feature in many neurodevelopmental disorders. Rett syndrome (RTT), a prevalent neurodevelopmental disorder that affects 1:10,000-15,000 women globally, is caused by loss-of-function mutations in the Methyl-CpG-binding Protein-2 (Mecp2) gene. E/I imbalance is recognized as the leading cellular and synaptic hallmark that is fundamental to diverse RTT neurological symptoms, including stereotypic hand movements, impaired motor coordination, breathing irregularities, seizures, and learning/memory dysfunctions. E/I balance in RTT is not homogeneously altered but demonstrates brain region and cell type specificity instead. In this review, I elaborate on the current understanding of the loss of E/I balance in a range of brain areas at molecular and cellular levels. I further describe how the underlying cellular mechanisms contribute to the disturbance of the proper E/I ratio. Last, I discuss current pharmacologic innervations for RTT and their role in modifying the E/I balance.
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Affiliation(s)
- Wei Li
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, United States
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10
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Kaur G, Rathod SSS, Ghoneim MM, Alshehri S, Ahmad J, Mishra A, Alhakamy NA. DNA Methylation: A Promising Approach in Management of Alzheimer's Disease and Other Neurodegenerative Disorders. BIOLOGY 2022; 11:90. [PMID: 35053088 PMCID: PMC8773419 DOI: 10.3390/biology11010090] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 01/03/2022] [Accepted: 01/04/2022] [Indexed: 12/13/2022]
Abstract
DNA methylation, in the mammalian genome, is an epigenetic modification that involves the transfer of a methyl group on the C5 position of cytosine to derive 5-methylcytosine. The role of DNA methylation in the development of the nervous system and the progression of neurodegenerative diseases such as Alzheimer's disease has been an interesting research area. Furthermore, mutations altering DNA methylation affect neurodevelopmental functions and may cause the progression of several neurodegenerative diseases. Epigenetic modifications in neurodegenerative diseases are widely studied in different populations to uncover the plausible mechanisms contributing to the development and progression of the disease and detect novel biomarkers for early prognosis and future pharmacotherapeutic targets. In this manuscript, we summarize the association of DNA methylation with the pathogenesis of the most common neurodegenerative diseases, such as, Alzheimer's disease, Parkinson's disease, Huntington diseases, and amyotrophic lateral sclerosis, and discuss the potential of DNA methylation as a potential biomarker and therapeutic tool for neurogenerative diseases.
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Affiliation(s)
- Gagandeep Kaur
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara 144411, Punjab, India; (G.K.); (S.S.S.R.)
| | - Suraj Singh S. Rathod
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara 144411, Punjab, India; (G.K.); (S.S.S.R.)
| | - Mohammed M. Ghoneim
- Department of Pharmacy Practice, College of Pharmacy, AlMaarefa University, Ad Diriyah 13713, Saudi Arabia;
| | - Sultan Alshehri
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia;
| | - Javed Ahmad
- Department of Pharmaceutics, College of Pharmacy, Najran University, Najran 11001, Saudi Arabia;
| | - Awanish Mishra
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER)—Guwahati, Changsari, Kamrup 781101, Assam, India
| | - Nabil A. Alhakamy
- Department of Pharmaceutics, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia;
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11
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Bach S, Shovlin S, Moriarty M, Bardoni B, Tropea D. Rett Syndrome and Fragile X Syndrome: Different Etiology With Common Molecular Dysfunctions. Front Cell Neurosci 2021; 15:764761. [PMID: 34867203 PMCID: PMC8640214 DOI: 10.3389/fncel.2021.764761] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/27/2021] [Indexed: 01/04/2023] Open
Abstract
Rett syndrome (RTT) and Fragile X syndrome (FXS) are two monogenetic neurodevelopmental disorders with complex clinical presentations. RTT is caused by mutations in the Methyl-CpG binding protein 2 gene (MECP2) altering the function of its protein product MeCP2. MeCP2 modulates gene expression by binding methylated CpG dinucleotides, and by interacting with transcription factors. FXS is caused by the silencing of the FMR1 gene encoding the Fragile X Mental Retardation Protein (FMRP), a RNA binding protein involved in multiple steps of RNA metabolism, and modulating the translation of thousands of proteins including a large set of synaptic proteins. Despite differences in genetic etiology, there are overlapping features in RTT and FXS, possibly due to interactions between MeCP2 and FMRP, and to the regulation of pathways resulting in dysregulation of common molecular signaling. Furthermore, basic physiological mechanisms are regulated by these proteins and might concur to the pathophysiology of both syndromes. Considering that RTT and FXS are disorders affecting brain development, and that most of the common targets of MeCP2 and FMRP are involved in brain activity, we discuss the mechanisms of synaptic function and plasticity altered in RTT and FXS, and we consider the similarities and the differences between these two disorders.
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Affiliation(s)
- Snow Bach
- School of Mathematical Sciences, Dublin City University, Dublin, Ireland.,Neuropsychiatric Genetics, Department of Psychiatry, School of Medicine, Trinity College Dublin, Trinity Translational Medicine Institute, St James's Hospital, Dublin, Ireland
| | - Stephen Shovlin
- Neuropsychiatric Genetics, Department of Psychiatry, School of Medicine, Trinity College Dublin, Trinity Translational Medicine Institute, St James's Hospital, Dublin, Ireland
| | | | - Barbara Bardoni
- Inserm, CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology, Université Côte d'Azur, Valbonne, France
| | - Daniela Tropea
- Neuropsychiatric Genetics, Department of Psychiatry, School of Medicine, Trinity College Dublin, Trinity Translational Medicine Institute, St James's Hospital, Dublin, Ireland.,Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland.,FutureNeuro, The SFI Research Centre for Chronic and Rare Neurological Diseases, Dublin, Ireland
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12
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Allison J, Kaliszewska A, Uceda S, Reiriz M, Arias N. Targeting DNA Methylation in the Adult Brain through Diet. Nutrients 2021; 13:nu13113979. [PMID: 34836233 PMCID: PMC8618930 DOI: 10.3390/nu13113979] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/05/2021] [Accepted: 11/05/2021] [Indexed: 02/07/2023] Open
Abstract
Metabolism and nutrition have a significant role in epigenetic modifications such as DNA methylation, which can influence gene expression. Recently, it has been suggested that bioactive nutrients and gut microbiota can alter DNA methylation in the central nervous system (CNS) through the gut-brain axis, playing a crucial role in modulating CNS functions and, finally, behavior. Here, we will focus on the effect of metabolic signals in shaping brain DNA methylation during adulthood. We will provide an overview of potential interactions among diet, gastrointestinal microbiome and epigenetic alterations on brain methylation and behavior. In addition, the impact of different diet challenges on cytosine methylation dynamics in the adult brain will be discussed. Finally, we will explore new ways to modulate DNA hydroxymethylation, which is particularly abundant in neural tissue, through diet.
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Affiliation(s)
- Joseph Allison
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, Denmark Hill, London SE5 8AF, UK; (J.A.); (A.K.)
| | - Aleksandra Kaliszewska
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, Denmark Hill, London SE5 8AF, UK; (J.A.); (A.K.)
| | - Sara Uceda
- BRABE Group, Department of Psychology, Faculty of Life and Natural Sciences, University of Nebrija, C/del Hostal, 28248 Madrid, Spain; (S.U.); (M.R.)
| | - Manuel Reiriz
- BRABE Group, Department of Psychology, Faculty of Life and Natural Sciences, University of Nebrija, C/del Hostal, 28248 Madrid, Spain; (S.U.); (M.R.)
| | - Natalia Arias
- BRABE Group, Department of Psychology, Faculty of Life and Natural Sciences, University of Nebrija, C/del Hostal, 28248 Madrid, Spain; (S.U.); (M.R.)
- Institute of Neurosciences of the Principality of Asturias (INEUROPA), 33003 Oviedo, Spain
- Health Research Institute of the Principality of Asturias—ISPA, 33011 Oviedo, Spain
- Correspondence: ; Tel.: +34-91-452-1101
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13
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Haase FD, Coorey B, Riley L, Cantrill LC, Tam PPL, Gold WA. Pre-clinical Investigation of Rett Syndrome Using Human Stem Cell-Based Disease Models. Front Neurosci 2021; 15:698812. [PMID: 34512241 PMCID: PMC8423999 DOI: 10.3389/fnins.2021.698812] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 07/19/2021] [Indexed: 01/02/2023] Open
Abstract
Rett syndrome (RTT) is an X-linked neurodevelopmental disorder, mostly caused by mutations in MECP2. The disorder mainly affects girls and it is associated with severe cognitive and physical disabilities. Modeling RTT in neural and glial cell cultures and brain organoids derived from patient- or mutation-specific human induced pluripotent stem cells (iPSCs) has advanced our understanding of the pathogenesis of RTT, such as disease-causing mechanisms, disease progression, and cellular and molecular pathology enabling the identification of actionable therapeutic targets. Brain organoid models that recapitulate much of the tissue architecture and the complexity of cell types in the developing brain, offer further unprecedented opportunity for elucidating human neural development, without resorting to conventional animal models and the limited resource of human neural tissues. This review focuses on the new knowledge of RTT that has been gleaned from the iPSC-based models as well as limitations of the models and strategies to refine organoid technology in the quest for clinically relevant disease models for RTT and the broader spectrum of neurodevelopmental disorders.
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Affiliation(s)
- Florencia D. Haase
- Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Kids Neuroscience Centre, Kids Research, Children’s Hospital at Westmead, Westmead, NSW, Australia
- Molecular Neurobiology Research Laboratory, Kids Research, Children’s Hospital at Westmead, and Children’s Medical Research Institute, Westmead, NSW, Australia
| | - Bronte Coorey
- Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Kids Neuroscience Centre, Kids Research, Children’s Hospital at Westmead, Westmead, NSW, Australia
- Molecular Neurobiology Research Laboratory, Kids Research, Children’s Hospital at Westmead, and Children’s Medical Research Institute, Westmead, NSW, Australia
| | - Lisa Riley
- Rare Diseases Functional Genomics Laboratory, Kids Research, Children’s Hospital at Westmead, and Children’s Medical Research Institute, Westmead, NSW, Australia
| | - Laurence C. Cantrill
- Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Kids Research, Children’s Hospital at Westmead, Westmead, NSW, Australia
| | - Patrick P. L. Tam
- Embryology Research Unit, Children’s Medical Research Institute, The University of Sydney, Sydney, NSW, Australia
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Wendy A. Gold
- Kids Neuroscience Centre, Kids Research, Children’s Hospital at Westmead, Westmead, NSW, Australia
- Molecular Neurobiology Research Laboratory, Kids Research, Children’s Hospital at Westmead, and Children’s Medical Research Institute, Westmead, NSW, Australia
- Rare Diseases Functional Genomics Laboratory, Kids Research, Children’s Hospital at Westmead, and Children’s Medical Research Institute, Westmead, NSW, Australia
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14
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D'Mello SR. MECP2 and the Biology of MECP2 Duplication Syndrome. J Neurochem 2021; 159:29-60. [PMID: 33638179 DOI: 10.1111/jnc.15331] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/21/2021] [Accepted: 02/18/2021] [Indexed: 11/27/2022]
Abstract
MECP2 duplication syndrome (MDS), a rare X-linked genomic disorder affecting predominantly males, is caused by duplication of the chromosomal region containing the methyl CpG binding protein-2 (MECP2) gene, which encodes methyl-CpG-binding protein 2 (MECP2), a multi-functional protein required for proper brain development and maintenance of brain function during adulthood. Disease symptoms include severe motor and cognitive impairment, delayed or absent speech development, autistic features, seizures, ataxia, recurrent respiratory infections and shortened lifespan. The cellular and molecular mechanisms by which a relatively modest increase in MECP2 protein causes such severe disease symptoms are poorly understood and consequently there are no treatments available for this fatal disorder. This review summarizes what is known to date about the structure and complex regulation of MECP2 and its many functions in the developing and adult brain. Additionally, recent experimental findings on the cellular and molecular underpinnings of MDS based on cell culture and mouse models of the disorder are reviewed. The emerging picture from these studies is that MDS is a neurodegenerative disorder in which neurons die in specific parts of the central nervous system, including the cortex, hippocampus, cerebellum and spinal cord. Neuronal death likely results from astrocytic dysfunction, including a breakdown of glutamate homeostatic mechanisms. The role of elevations in the expression of glial acidic fibrillary protein (GFAP) in astrocytes and the microtubule-associated protein, Tau, in neurons to the pathogenesis of MDS is discussed. Lastly, potential therapeutic strategies to potentially treat MDS are discussed.
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15
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Gomathi M, Padmapriya S, Balachandar V. Drug Studies on Rett Syndrome: From Bench to Bedside. J Autism Dev Disord 2020; 50:2740-2764. [PMID: 32016693 DOI: 10.1007/s10803-020-04381-y] [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] [Indexed: 12/20/2022]
Abstract
Drug studies on Rett syndrome (RTT) have drastically increased over the past few decades. This review aims to provide master data on bench-to-bedside drug studies involving RTT. A comprehensive literature review was performed by searching in PUBMED, MEDLINE and Google Scholar, international, national and regional clinical trial registries and pharmaceutical companies using the keywords "Rett syndrome treatment and/or drug or compound or molecule". Seventy drugs were investigated in non-clinical (N = 65 animal/cell line-based studies; N = 5 iPSC-based study) and clinical trials (N = 34) for ameliorating the symptoms of RTT. Though there is good progress in both clinical and non-clinical studies, none of these drugs entered phase III/IV for being launched as a therapeutic agent for RTT.
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Affiliation(s)
- Mohan Gomathi
- Human Molecular Genetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore, Tamil Nadu, 641046, India
| | | | - Vellingiri Balachandar
- Human Molecular Genetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore, Tamil Nadu, 641046, India.
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16
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Ramirez JM, Karlen-Amarante M, Wang JDJ, Bush NE, Carroll MS, Weese-Mayer DE, Huff A. The Pathophysiology of Rett Syndrome With a Focus on Breathing Dysfunctions. Physiology (Bethesda) 2020; 35:375-390. [PMID: 33052774 PMCID: PMC7864239 DOI: 10.1152/physiol.00008.2020] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 06/21/2020] [Accepted: 06/22/2020] [Indexed: 02/07/2023] Open
Abstract
Rett syndrome (RTT), an X-chromosome-linked neurological disorder, is characterized by serious pathophysiology, including breathing and feeding dysfunctions, and alteration of cardiorespiratory coupling, a consequence of multiple interrelated disturbances in the genetic and homeostatic regulation of central and peripheral neuronal networks, redox state, and control of inflammation. Characteristic breath-holds, obstructive sleep apnea, and aerophagia result in intermittent hypoxia, which, combined with mitochondrial dysfunction, causes oxidative stress-an important driver of the clinical presentation of RTT.
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Affiliation(s)
- Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, Washington
- Departments of Neurological Surgery and Pediatrics, University of Washington School of Medicine, Seattle, Washington
| | - Marlusa Karlen-Amarante
- Center for Integrative Brain Research, Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, Washington
- Department of Physiology and Pathology, School of Dentistry of Araraquara, São Paulo State University (UNESP), Araraquara, Brazil
| | - Jia-Der Ju Wang
- Center for Integrative Brain Research, Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, Washington
| | - Nicholas E Bush
- Center for Integrative Brain Research, Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, Washington
| | - Michael S Carroll
- Data Analytics and Reporting, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
- Division of Autonomic Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Debra E Weese-Mayer
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
- Division of Autonomic Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Alyssa Huff
- Center for Integrative Brain Research, Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, Washington
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17
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Kavalali ET, Monteggia LM. Targeting Homeostatic Synaptic Plasticity for Treatment of Mood Disorders. Neuron 2020; 106:715-726. [PMID: 32497508 DOI: 10.1016/j.neuron.2020.05.015] [Citation(s) in RCA: 96] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/05/2020] [Accepted: 05/07/2020] [Indexed: 01/23/2023]
Abstract
Ketamine exerts rapid antidepressant action in depressed and treatment-resistant depressed patients within hours. At the same time, ketamine elicits a unique form of functional synaptic plasticity that shares several attributes and molecular mechanisms with well-characterized forms of homeostatic synaptic scaling. Lithium is a widely used mood stabilizer also proposed to act via synaptic scaling for its antimanic effects. Several studies to date have identified specific forms of homeostatic synaptic plasticity that are elicited by these drugs used to treat neuropsychiatric disorders. In the last two decades, extensive work on homeostatic synaptic plasticity mechanisms have shown that they diverge from classical synaptic plasticity mechanisms that process and store information and thus present a novel avenue for synaptic regulation with limited direct interference with cognitive processes. In this review, we discuss the intersection of the findings from neuropsychiatric treatments and homeostatic plasticity studies to highlight a potentially wider paradigm for treatment advance.
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Affiliation(s)
- Ege T Kavalali
- Department of Pharmacology and the Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA.
| | - Lisa M Monteggia
- Department of Pharmacology and the Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA.
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18
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Javed S, Selliah T, Lee YJ, Huang WH. Dosage-sensitive genes in autism spectrum disorders: From neurobiology to therapy. Neurosci Biobehav Rev 2020; 118:538-567. [PMID: 32858083 DOI: 10.1016/j.neubiorev.2020.08.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/26/2020] [Accepted: 08/17/2020] [Indexed: 12/24/2022]
Abstract
Autism spectrum disorders (ASDs) are a group of heterogenous neurodevelopmental disorders affecting 1 in 59 children. Syndromic ASDs are commonly associated with chromosomal rearrangements or dosage imbalance involving a single gene. Many of these genes are dosage-sensitive and regulate transcription, protein homeostasis, and synaptic function in the brain. Despite vastly different molecular perturbations, syndromic ASDs share core symptoms including social dysfunction and repetitive behavior. However, each ASD subtype has a unique pathogenic mechanism and combination of comorbidities that require individual attention. We have learned a great deal about how these dosage-sensitive genes control brain development and behaviors from genetically-engineered mice. Here we describe the clinical features of eight monogenic neurodevelopmental disorders caused by dosage imbalance of four genes, as well as recent advances in using genetic mouse models to understand their pathogenic mechanisms and develop intervention strategies. We propose that applying newly developed quantitative molecular and neuroscience technologies will advance our understanding of the unique neurobiology of each disorder and enable the development of personalized therapy.
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Affiliation(s)
- Sehrish Javed
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, The Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Tharushan Selliah
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, The Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Yu-Ju Lee
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, The Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Wei-Hsiang Huang
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, The Research Institute of the McGill University Health Centre, Montréal, Québec, Canada.
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19
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Horvath PM, Piazza MK, Monteggia LM, Kavalali ET. Spontaneous and evoked neurotransmission are partially segregated at inhibitory synapses. eLife 2020; 9:52852. [PMID: 32401197 PMCID: PMC7250572 DOI: 10.7554/elife.52852] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 05/13/2020] [Indexed: 12/27/2022] Open
Abstract
Synaptic transmission is initiated via spontaneous or action-potential evoked fusion of synaptic vesicles. At excitatory synapses, glutamatergic receptors activated by spontaneous and evoked neurotransmission are segregated. Although inhibitory synapses also transmit signals spontaneously or in response to action potentials, they differ from excitatory synapses in both structure and function. Therefore, we hypothesized that inhibitory synapses may have different organizing principles. We report picrotoxin, a GABAAR antagonist, blocks neurotransmission in a use-dependent manner at rat hippocampal synapses and therefore can be used to interrogate synaptic properties. Using this tool, we uncovered partial segregation of inhibitory spontaneous and evoked neurotransmission. We found up to 40% of the evoked response is mediated through GABAARs which are only activated by evoked neurotransmission. These data indicate GABAergic spontaneous and evoked neurotransmission processes are partially non-overlapping, suggesting they may serve divergent roles in neuronal signaling.
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Affiliation(s)
- Patricia M Horvath
- Department of Pharmacology, Vanderbilt University, Nashville, United States.,Department of Neuroscience, the University of Texas Southwestern Medical Center, Dallas, United States
| | - Michelle K Piazza
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, United States.,Neuroscience Program, Vanderbilt University, Nashville, United States
| | - Lisa M Monteggia
- Department of Pharmacology, Vanderbilt University, Nashville, United States.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, United States
| | - Ege T Kavalali
- Department of Pharmacology, Vanderbilt University, Nashville, United States.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, United States
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20
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Zhu L, Chen L, Xu P, Lu D, Dai S, Zhong L, Han Y, Zhang M, Xiao B, Chang L, Wu Q. Genetic and molecular basis of epilepsy-related cognitive dysfunction. Epilepsy Behav 2020; 104:106848. [PMID: 32028124 DOI: 10.1016/j.yebeh.2019.106848] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 12/06/2019] [Accepted: 12/06/2019] [Indexed: 02/02/2023]
Abstract
Epilepsy is a common neurological disease characterized by recurrent seizures. About 70 million people were affected by epilepsy or epileptic seizures. Epilepsy is a complicated complex or symptomatic syndromes induced by structural, functional, and genetic causes. Meanwhile, several comorbidities are accompanied by epileptic seizures. Cognitive dysfunction is a long-standing complication associated with epileptic seizures, which severely impairs quality of life. Although the definitive pathogenic mechanisms underlying epilepsy-related cognitive dysfunction remain unclear, accumulating evidence indicates that multiple risk factors are probably involved in the development and progression of cognitive dysfunction in patients with epilepsy. These factors include the underlying etiology, recurrent seizures or status epilepticus, structural damage that induced secondary epilepsy, genetic variants, and molecular alterations. In this review, we summarize several theories that may explain the genetic and molecular basis of epilepsy-related cognitive dysfunction.
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Affiliation(s)
- Lin Zhu
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China
| | - Lu Chen
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China
| | - Puying Xu
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China
| | - Di Lu
- Biomedicine Engineering Research Center, Kunming Medical University, 1168 Chun Rong West Road, Kunming, Yunnan 650500, PR China
| | - Shujuan Dai
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China
| | - Lianmei Zhong
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China
| | - Yanbing Han
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China
| | - Mengqi Zhang
- Department of Neurology, Xiangya Hospital, Central South University, 87 Xiang Ya Road, Changsha, Hunan 410008, PR China
| | - Bo Xiao
- Department of Neurology, Xiangya Hospital, Central South University, 87 Xiang Ya Road, Changsha, Hunan 410008, PR China
| | - Lvhua Chang
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China.
| | - Qian Wu
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China.
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21
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Abstract
Despite decades of research on Alzheimer disease, understanding the complexity of the genetic and molecular interactions involved in its pathogenesis remains far from our grasp. Methyl-CpG Binding Protein 2 (MeCP2) is an important epigenetic regulator enriched in the brain, and recent findings have implicated MeCP2 as a crucial player in Alzheimer disease. Here, we provide comprehensive insights into the pathophysiological roles of MeCP2 in Alzheimer disease. In particular, we focus on how the alteration of MeCP2 expression can impact Alzheimer disease through risk genes, amyloid-β and tau pathology, cell death and neurodegeneration, and cellular senescence. We suggest that Alzheimer disease can be adversely affected by upregulated MeCP2-dependent repression of risk genes (MEF2C, ADAM10, and PM20D1), increased tau accumulation, and neurodegeneration through neuronal cell death (excitotoxicity and apoptosis). In addition, we propose that the progression of Alzheimer disease could be caused by reduced MeCP2-mediated enhancement of astrocytic and microglial senescence and consequent glial SASP (senescence-associated secretory phenotype)-dependent neuroinflammation. We surmise that any imbalance in MeCP2 function would accelerate or cause Alzheimer disease pathogenesis, implying that MeCP2 may be a potential drug target for the treatment and prevention of Alzheimer disease.
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22
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Sysoeva OV, Smirnov K, Stroganova TA. Sensory evoked potentials in patients with Rett syndrome through the lens of animal studies: Systematic review. Clin Neurophysiol 2019; 131:213-224. [PMID: 31812082 DOI: 10.1016/j.clinph.2019.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 11/07/2019] [Accepted: 11/11/2019] [Indexed: 01/04/2023]
Abstract
OBJECTIVE Systematically review the abnormalities in event related potential (ERP) recorded in Rett Syndrome (RTT) patients and animals in search of translational biomarkers of deficits related to the particular neurophysiological processes of known genetic origin (MECP2 mutations). METHODS Pubmed, ISI Web of Knowledge and BIORXIV were searched for the relevant articles according to PRISMA standards. RESULTS ERP components are generally delayed across all sensory modalities both in RTT patients and its animal model, while findings on ERPs amplitude strongly depend on stimulus properties and presentation rate. Studies on RTT animal models uncovered the abnormalities in the excitatory and inhibitory transmission as critical mechanisms underlying the ERPs changes, but showed that even similar ERP alterations in auditory and visual domains have a diverse neural basis. A range of novel approaches has been developed in animal studies bringing along the meaningful neurophysiological interpretation of ERP measures in RTT patients. CONCLUSIONS While there is a clear evidence for sensory ERPs abnormalities in RTT, to further advance the field there is a need in a large-scale ERP studies with the functionally-relevant experimental paradigms. SIGNIFICANCE The review provides insights into domain-specific neural basis of the ERP abnormalities and promotes clinical application of the ERP measures as the non-invasive functional biomarkers of RTT pathophysiology.
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Affiliation(s)
- Olga V Sysoeva
- The Cognitive Neurophysiology Laboratory, Department of Pediatrics, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, USA; The Cognitive Neurophysiology Laboratory, Ernest J. Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA; The Laboratory of Human Higher Nervous Activity, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia.
| | - Kirill Smirnov
- Department of Neuroontogenesis, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Science, Moscow, Russia.
| | - Tatiana A Stroganova
- Center for Neurocognitive Research (MEG-Center), Moscow State University of Psychology and Education (MSUPE), Moscow, Russia; Autism Research Laboratory, Moscow State University of Psychology and Education (MSUPE), Moscow, Russia.
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23
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Smith ES, Smith DR, Eyring C, Braileanu M, Smith-Connor KS, Ei Tan Y, Fowler AY, Hoffman GE, Johnston MV, Kannan S, Blue ME. Altered trajectories of neurodevelopment and behavior in mouse models of Rett syndrome. Neurobiol Learn Mem 2019; 165:106962. [PMID: 30502397 PMCID: PMC8040058 DOI: 10.1016/j.nlm.2018.11.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 10/17/2018] [Accepted: 11/16/2018] [Indexed: 12/12/2022]
Abstract
Rett Syndrome (RTT) is a genetic disorder that is caused by mutations in the x-linked gene coding for methyl-CpG-biding-protein 2 (MECP2) and that mainly affects females. Male and female transgenic mouse models of RTT have been studied extensively, and we have learned a great deal regarding RTT neuropathology and how MeCP2 deficiency may be influencing brain function and maturation. In this manuscript we review what is known concerning structural and coinciding functional and behavioral deficits in RTT and in mouse models of MeCP2 deficiency. We also introduce our own corroborating data regarding behavioral phenotype and morphological alterations in volume of the cortex and striatum and the density of neurons, aberrations in experience-dependent plasticity within the barrel cortex and the impact of MeCP2 loss on glial structure. We conclude that regional structural changes in genetic models of RTT show great similarity to the alterations in brain structure of patients with RTT. These region-specific modifications often coincide with phenotype onset and contribute to larger issues of circuit connectivity, progression, and severity. Although the alterations seen in mouse models of RTT appear to be primarily due to cell-autonomous effects, there are also non-cell autonomous mechanisms including those caused by MeCP2-deficient glia that negatively impact healthy neuronal function. Collectively, this body of work has provided a solid foundation on which to continue to build our understanding of the role of MeCP2 on neuronal and glial structure and function, its greater impact on neural development, and potential new therapeutic avenues.
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Affiliation(s)
- Elizabeth S Smith
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Dani R Smith
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Charlotte Eyring
- The Hugo W. Moser Research Institute at Kennedy Krieger, Inc., Baltimore, MD 21205, USA
| | - Maria Braileanu
- Undergraduate Program in Neuroscience, The Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Karen S Smith-Connor
- The Hugo W. Moser Research Institute at Kennedy Krieger, Inc., Baltimore, MD 21205, USA
| | - Yew Ei Tan
- Perdana University Graduate School of Medicine, Kuala Lumpur, Malaysia
| | - Amanda Y Fowler
- Department of Biology, Morgan State University, Baltimore, MD 21251, USA
| | - Gloria E Hoffman
- Department of Biology, Morgan State University, Baltimore, MD 21251, USA
| | - Michael V Johnston
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Hugo W. Moser Research Institute at Kennedy Krieger, Inc., Baltimore, MD 21205, USA
| | - Sujatha Kannan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Hugo W. Moser Research Institute at Kennedy Krieger, Inc., Baltimore, MD 21205, USA
| | - Mary E Blue
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Hugo W. Moser Research Institute at Kennedy Krieger, Inc., Baltimore, MD 21205, USA.
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24
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Banerjee A, Miller MT, Li K, Sur M, Kaufmann WE. Towards a better diagnosis and treatment of Rett syndrome: a model synaptic disorder. Brain 2019; 142:239-248. [PMID: 30649225 DOI: 10.1093/brain/awy323] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 10/31/2018] [Indexed: 12/21/2022] Open
Abstract
With the recent 50th anniversary of the first publication on Rett syndrome, and the almost 20 years since the first report on the link between Rett syndrome and MECP2 mutations, it is important to reflect on the tremendous advances in our understanding and their implications for the diagnosis and treatment of this neurodevelopmental disorder. Rett syndrome features an interesting challenge for biologists and clinicians, as the disorder lies at the intersection of molecular mechanisms of epigenetic regulation and neurophysiological alterations in synapses and circuits that together contribute to severe pathophysiological endophenotypes. Genetic, clinical, and neurobiological evidences support the notion that Rett syndrome is primarily a synaptic disorder, and a disease model for both intellectual disability and autism spectrum disorder. This review examines major developments in both recent neurobiological and preclinical findings of Rett syndrome, and to what extent they are beginning to impact our understanding and management of the disorder. It also discusses potential applications of knowledge on synaptic plasticity abnormalities in Rett syndrome to its diagnosis and treatment.
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Affiliation(s)
- Abhishek Banerjee
- Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zürich, Zürich, Switzerland
| | - Meghan T Miller
- Roche Pharma Research and Early Development, Roche Innovation Center, F. Hoffman-La Roche, Basel, Switzerland
| | - Keji Li
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge MA, USA
| | - Mriganka Sur
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge MA, USA
| | - Walter E Kaufmann
- Department of Human Genetics, Emory University School of Medicine, Atlanta GA, USA
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25
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Gulmez Karaca K, Brito DV, Oliveira AM. MeCP2: A Critical Regulator of Chromatin in Neurodevelopment and Adult Brain Function. Int J Mol Sci 2019; 20:ijms20184577. [PMID: 31527487 PMCID: PMC6769791 DOI: 10.3390/ijms20184577] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 09/11/2019] [Accepted: 09/12/2019] [Indexed: 01/08/2023] Open
Abstract
Methyl CpG binding protein 2 (MeCP2) was first identified as a nuclear protein with a transcriptional repressor role that recognizes DNA methylation marks. MeCP2 has a well-established function in neurodevelopment, as evidenced by the severe neurological impairments characteristic of the Rett syndrome (RTT) pathology and the MeCP2 duplication syndrome (MDS), caused by loss or gain of MeCP2 function, respectively. Research aimed at the underlying pathophysiological mechanisms of RTT and MDS has significantly advanced our understanding of MeCP2 functions in the nervous system. It has revealed, however, that MeCP2 has more varied and complex roles than previously thought. Here we review recent insights into the functions of MeCP2 in neurodevelopment and the less explored requirement for MeCP2 in adult brain function. We focus on the emerging view that MeCP2 is a global chromatin organizer. Finally, we discuss how the individual functions of MeCP2 in neurodevelopment and adulthood are linked to its role as a chromatin regulator.
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Affiliation(s)
- Kubra Gulmez Karaca
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, 69120 Heidelberg, Germany; (K.G.K.)
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 EN Nijmegen, The Netherlands
| | - David V.C. Brito
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, 69120 Heidelberg, Germany; (K.G.K.)
| | - Ana M.M. Oliveira
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, 69120 Heidelberg, Germany; (K.G.K.)
- Correspondence: ; Tel.: +49-(0)6221-5416510
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26
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Abstract
Rett syndrome (RTT) is a severe neurological disorder caused by mutations in the gene encoding methyl-CpG-binding protein 2 (MeCP2). Almost two decades of research into RTT have greatly advanced our understanding of the function and regulation of the multifunctional protein MeCP2. Here, we review recent advances in understanding how loss of MeCP2 impacts different stages of brain development, discuss recent findings demonstrating the molecular role of MeCP2 as a transcriptional repressor, assess primary and secondary effects of MeCP2 loss and examine how loss of MeCP2 can result in an imbalance of neuronal excitation and inhibition at the circuit level along with dysregulation of activity-dependent mechanisms. These factors present challenges to the search for mechanism-based therapeutics for RTT and suggest specific approaches that may be more effective than others.
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27
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Tang X, Drotar J, Li K, Clairmont CD, Brumm AS, Sullins AJ, Wu H, Liu XS, Wang J, Gray NS, Sur M, Jaenisch R. Pharmacological enhancement of KCC2 gene expression exerts therapeutic effects on human Rett syndrome neurons and Mecp2 mutant mice. Sci Transl Med 2019; 11:eaau0164. [PMID: 31366578 PMCID: PMC8140401 DOI: 10.1126/scitranslmed.aau0164] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 04/14/2019] [Accepted: 07/12/2019] [Indexed: 12/14/2022]
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in the methyl CpG binding protein 2 (MECP2) gene. There are currently no approved treatments for RTT. The expression of K+/Cl- cotransporter 2 (KCC2), a neuron-specific protein, has been found to be reduced in human RTT neurons and in RTT mouse models, suggesting that KCC2 might play a role in the pathophysiology of RTT. To develop neuron-based high-throughput screening (HTS) assays to identify chemical compounds that enhance the expression of the KCC2 gene, we report the generation of a robust high-throughput drug screening platform that allows for the rapid assessment of KCC2 gene expression in genome-edited human reporter neurons. From an unbiased screen of more than 900 small-molecule chemicals, we have identified a group of compounds that enhance KCC2 expression termed KCC2 expression-enhancing compounds (KEECs). The identified KEECs include U.S. Food and Drug Administration-approved drugs that are inhibitors of the fms-like tyrosine kinase 3 (FLT3) or glycogen synthase kinase 3β (GSK3β) pathways and activators of the sirtuin 1 (SIRT1) and transient receptor potential cation channel subfamily V member 1 (TRPV1) pathways. Treatment with hit compounds increased KCC2 expression in human wild-type (WT) and isogenic MECP2 mutant RTT neurons, and rescued electrophysiological and morphological abnormalities of RTT neurons. Injection of KEEC KW-2449 or piperine in Mecp2 mutant mice ameliorated disease-associated respiratory and locomotion phenotypes. The small-molecule compounds described in our study may have therapeutic effects not only in RTT but also in other neurological disorders involving dysregulation of KCC2.
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Affiliation(s)
- Xin Tang
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Jesse Drotar
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Keji Li
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | | | - Austin J Sullins
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Hao Wu
- Fulcrum Therapeutics, Cambridge, MA 02139, USA
| | | | - Jinhua Wang
- Department of Cancer Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Nathanael S Gray
- Department of Cancer Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Mriganka Sur
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Rudolf Jaenisch
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
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28
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Verma V, Paul A, Amrapali Vishwanath A, Vaidya B, Clement JP. Understanding intellectual disability and autism spectrum disorders from common mouse models: synapses to behaviour. Open Biol 2019; 9:180265. [PMID: 31185809 PMCID: PMC6597757 DOI: 10.1098/rsob.180265] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Normal brain development is highly dependent on the timely coordinated actions of genetic and environmental processes, and an aberration can lead to neurodevelopmental disorders (NDDs). Intellectual disability (ID) and autism spectrum disorders (ASDs) are a group of co-occurring NDDs that affect between 3% and 5% of the world population, thus presenting a great challenge to society. This problem calls for the need to understand the pathobiology of these disorders and to design new therapeutic strategies. One approach towards this has been the development of multiple analogous mouse models. This review discusses studies conducted in the mouse models of five major monogenic causes of ID and ASDs: Fmr1, Syngap1, Mecp2, Shank2/3 and Neuroligins/Neurnexins. These studies reveal that, despite having a diverse molecular origin, the effects of these mutations converge onto similar or related aetiological pathways, consequently giving rise to the typical phenotype of cognitive, social and emotional deficits that are characteristic of ID and ASDs. This convergence, therefore, highlights common pathological nodes that can be targeted for therapy. Other than conventional therapeutic strategies such as non-pharmacological corrective methods and symptomatic alleviation, multiple studies in mouse models have successfully proved the possibility of pharmacological and genetic therapy enabling functional recovery.
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Affiliation(s)
- Vijaya Verma
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bengaluru 560 064, Karnataka, India
| | - Abhik Paul
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bengaluru 560 064, Karnataka, India
| | - Anjali Amrapali Vishwanath
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bengaluru 560 064, Karnataka, India
| | - Bhupesh Vaidya
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bengaluru 560 064, Karnataka, India
| | - James P Clement
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bengaluru 560 064, Karnataka, India
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29
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Sun Y, Gao Y, Tidei JJ, Shen M, Hoang JT, Wagner DF, Zhao X. Loss of MeCP2 in immature neurons leads to impaired network integration. Hum Mol Genet 2019; 28:245-257. [PMID: 30277526 DOI: 10.1093/hmg/ddy338] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Accepted: 09/18/2018] [Indexed: 12/12/2022] Open
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations or deletions in Methyl-CpG-binding Protein 2 (MeCP2), a brain-enriched transcriptional regulator. MeCP2 is highly expressed during neuronal maturation and its deficiency results in impaired dendritic morphogenesis and reduced dendritic spine numbers in developing neurons. However, whether MeCP2 deficiency impacts the integration of new neurons has not been directly assessed. In this study, we developed a modified rabies virus-mediated monosynaptic retrograde tracing method to interrogate presynaptic integration of MeCP2-deficient new neurons born in the adult hippocampus, a region with lifelong neurogenesis and plasticity. We found that selective deletion of MeCP2 in adult-born new neurons impaired their long-range connectivity to the cortex, whereas their connectivity within the local hippocampal circuits or with subcortical regions was not significantly affected. We further showed that knockdown of MeCP2 in primary hippocampal neurons also resulted in reduced network integration. Interestingly, (1-3) insulin-like growth factor-1 (IGF-1), a small peptide under clinical trial testing for RTT, rescued neuronal integration deficits of MeCP2-deficient neurons in vitro but not in vivo. In addition, (1-3) IGF-1 treatment corrected aberrant excitability and network synchrony of MeCP2-deficient hippocampal neurons. Our results indicate that MeCP2 is essential for immature neurons to establish appropriate network connectivity.
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Affiliation(s)
- Yi Sun
- National Key Research Laboratory of Natural and Biomimetic Drugs.,Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing, PR China.,Waisman Center
| | - Yu Gao
- Waisman Center.,Department of Neuroscience
| | | | | | | | | | - Xinyu Zhao
- Waisman Center.,Department of Neuroscience.,Cellular and Molecular Biology Program, University of Wisconsin-Madison, Madison, WI, USA
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30
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Harman MF, Martín MG. Epigenetic mechanisms related to cognitive decline during aging. J Neurosci Res 2019; 98:234-246. [PMID: 31045277 DOI: 10.1002/jnr.24436] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 04/04/2019] [Accepted: 04/12/2019] [Indexed: 12/12/2022]
Abstract
Cognitive decline is a hallmark of the aging nervous system, characterized by increasing memory loss and a deterioration of mental capacity, which in turn creates a favorable context for the development of neurodegenerative diseases. One of the most detrimental alterations that occur at the molecular level in the brain during aging is the modification of the epigenetic mechanisms that control gene expression. As a result of these epigenetic-driven changes in the transcriptome most of the functions of the brain including synaptic plasticity, learning, and memory decline with aging. The epigenetic mechanisms altered during aging include DNA methylation, histone modifications, nucleosome remodeling, and microRNA-mediated gene regulation. In this review, we examine the current evidence concerning the changes of epigenetic modifications together with the molecular mechanisms underlying impaired neuronal gene transcription during aging. Herein, we discuss the alterations of DNA methylation pattern that occur in old neurons. We will also describe the most prominent age-related histone posttranslational modifications in the brain since changes in acetylation and methylation of specific lysine residues on H3 and H4 are associated to functional decline in the old. In addition, we discuss the role that changes in the levels of certain miRNAs would play in cognitive decline with aging. Finally, we provide an overview about the mechanisms either extrinsic or intrinsic that would trigger epigenetic changes in the aging brain, and the consequences of these changes, i.e., altered transcriptional profile and reactivation of transposable elements in old brain.
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Affiliation(s)
- María F Harman
- Instituto Ferreyra, INIMEC-CONICET-UNC, Córdoba, Argentina.,Facultad de Ciencias Químicas, Departamento de Bioquímica Clínica, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Mauricio G Martín
- Instituto Ferreyra, INIMEC-CONICET-UNC, Córdoba, Argentina.,Facultad de Ciencias Exactas Físicas y Naturales, Cátedra de Química Orgánica, Universidad Nacional de Córdoba, Córdoba, Argentina
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31
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32
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Abstract
In the past few decades, the field of neuroepigenetics has investigated how the brain encodes information to form long-lasting memories that lead to stable changes in behaviour. Activity-dependent molecular mechanisms, including, but not limited to, histone modification, DNA methylation and nucleosome remodelling, dynamically regulate the gene expression required for memory formation. Recently, the field has begun to examine how a learning experience is integrated at the level of both chromatin structure and synaptic physiology. Here, we provide an overview of key established epigenetic mechanisms that are important for memory formation. We explore how epigenetic mechanisms give rise to stable alterations in neuronal function by modifying synaptic structure and function, and highlight studies that demonstrate how manipulating epigenetic mechanisms may push the boundaries of memory.
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Affiliation(s)
- Rianne R Campbell
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, Center for Addiction Neuroscience, Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
| | - Marcelo A Wood
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, Center for Addiction Neuroscience, Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA.
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33
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Characterization of human mosaic Rett syndrome brain tissue by single-nucleus RNA sequencing. Nat Neurosci 2018; 21:1670-1679. [PMID: 30455458 PMCID: PMC6261686 DOI: 10.1038/s41593-018-0270-6] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 09/25/2018] [Indexed: 12/22/2022]
Abstract
In females with X-linked genetic disorders, wild-type and mutant cells coexist within brain tissue because of X-chromosome inactivation, posing challenges for interpreting the effects of X-linked mutant alleles on gene expression. We present a single-nucleus RNA sequencing approach that resolves mosaicism by using single-nucleotide polymorphisms in genes expressed in cis with the X-linked mutation to determine which nuclei express the mutant allele even when the mutant gene is not detected. This approach enables gene expression comparisons between mutant and wild-type cells within the same individual, eliminating variability introduced by comparisons to controls with different genetic backgrounds. We apply this approach to mosaic female mouse models and humans with Rett syndrome, an X-linked neurodevelopmental disorder caused by mutations in the gene encoding the methyl-DNA-binding protein MECP2, and observe that cell-type-specific DNA methylation predicts the degree of gene upregulation in MECP2-mutant neurons. This approach can be broadly applied to study gene expression in mosaic X-linked disorders.
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34
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Subbanna S, Nagre NN, Shivakumar M, Joshi V, Psychoyos D, Kutlar A, Umapathy NS, Basavarajappa BS. CB1R-Mediated Activation of Caspase-3 Causes Epigenetic and Neurobehavioral Abnormalities in Postnatal Ethanol-Exposed Mice. Front Mol Neurosci 2018; 11:45. [PMID: 29515368 PMCID: PMC5826222 DOI: 10.3389/fnmol.2018.00045] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 02/02/2018] [Indexed: 12/15/2022] Open
Abstract
Alcohol exposure can affect brain development, leading to long-lasting behavioral problems, including cognitive impairment, which together is defined as fetal alcohol spectrum disorder (FASD). However, the fundamental mechanisms through which this occurs are largely unknown. In this study, we report that the exposure of postnatal day 7 (P7) mice to ethanol activates caspase-3 via cannabinoid receptor type-1 (CB1R) in neonatal mice and causes a reduction in methylated DNA binding protein (MeCP2) levels. The developmental expression of MeCP2 in mice is closely correlated with synaptogenesis and neuronal maturation. It was shown that ethanol treatment of P7 mice enhanced Mecp2 mRNA levels but reduced protein levels. The genetic deletion of CB1R prevented, and administration of a CB1R antagonist before ethanol treatment of P7 mice inhibited caspase-3 activation. Additionally, it reversed the loss of MeCP2 protein, cAMP response element binding protein (CREB) activation, and activity-regulated cytoskeleton-associated protein (Arc) expression. The inhibition of caspase-3 activity prior to ethanol administration prevented ethanol-induced loss of MeCP2, CREB activation, epigenetic regulation of Arc expression, long-term potentiation (LTP), spatial memory deficits and activity-dependent impairment of several signaling molecules, including MeCP2, in adult mice. Collectively, these results reveal that the ethanol-induced CB1R-mediated activation of caspase-3 degrades the MeCP2 protein in the P7 mouse brain and causes long-lasting neurobehavioral deficits in adult mice. This CB1R-mediated instability of MeCP2 during active synaptic maturation may disrupt synaptic circuit maturation and lead to neurobehavioral abnormalities, as observed in this animal model of FASD.
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Affiliation(s)
- Shivakumar Subbanna
- Division of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, New York, NY, United States
| | - Nagaraja N. Nagre
- Division of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, New York, NY, United States
| | - Madhu Shivakumar
- Division of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, New York, NY, United States
| | - Vikram Joshi
- Division of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, New York, NY, United States
| | - Delphine Psychoyos
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX, United States
| | - Abdullah Kutlar
- Center for Blood Disorders, Augusta University, Augusta, GA, United States
| | | | - Balapal S. Basavarajappa
- Division of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, New York, NY, United States
- New York State Psychiatric Institute, New York, NY, United States
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY, United States
- Department of Psychiatry, New York University Langone Medical Center, New York, NY, United States
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35
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Kathuria A, Nowosiad P, Jagasia R, Aigner S, Taylor RD, Andreae LC, Gatford NJF, Lucchesi W, Srivastava DP, Price J. Stem cell-derived neurons from autistic individuals with SHANK3 mutation show morphogenetic abnormalities during early development. Mol Psychiatry 2018; 23:735-746. [PMID: 28948968 PMCID: PMC5822449 DOI: 10.1038/mp.2017.185] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 07/04/2017] [Accepted: 07/19/2017] [Indexed: 01/02/2023]
Abstract
Shank3 is a structural protein found predominantly at the postsynaptic density. Mutations in the SHANK3 gene have been associated with risk for autism spectrum disorder (ASD). We generated induced pluripotent stem cells (iPSCs) from control individuals and from human donors with ASD carrying microdeletions of SHANK3. In addition, we used Zinc finger nucleases to generate isogenic SHANK3 knockout human embryonic stem (ES) cell lines. We differentiated pluripotent cells into either cortical or olfactory placodal neurons. We show that patient-derived placodal neurons make fewer synapses than control cells. Moreover, patient-derived cells display a developmental phenotype: young postmitotic neurons have smaller cell bodies, more extensively branched neurites, and reduced motility compared with controls. These phenotypes were mimicked by SHANK3-edited ES cells and rescued by transduction with a Shank3 expression construct. This developmental phenotype is not observed in the same iPSC lines differentiated into cortical neurons. Therefore, we suggest that SHANK3 has a critical role in neuronal morphogenesis in placodal neurons and that early defects are associated with ASD-associated mutations.
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Affiliation(s)
- A Kathuria
- Cells & Behavior Unit, Department of Basic and Clinical Neuroscience, Institute of Psychiatry Psychology & Neuroscience, King’s College London, London, UK
| | - P Nowosiad
- Cells & Behavior Unit, Department of Basic and Clinical Neuroscience, Institute of Psychiatry Psychology & Neuroscience, King’s College London, London, UK
| | - R Jagasia
- CNS Discovery/F-Hoffmann-La Roche Ltd, Basel, Switzerland
| | - S Aigner
- Department of Cellular and Molecular Medicine School of Medicine University of California, San Diego, CA, USA
| | - R D Taylor
- Developmental Neurobiology/New Hunt’s House Guy’s Campus, King’s College London, London, UK,MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK
| | - L C Andreae
- Developmental Neurobiology/New Hunt’s House Guy’s Campus, King’s College London, London, UK,MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK
| | - N J F Gatford
- Cells & Behavior Unit, Department of Basic and Clinical Neuroscience, Institute of Psychiatry Psychology & Neuroscience, King’s College London, London, UK
| | - W Lucchesi
- School of Biological Sciences, Royal Holloway, University of London, Egham, UK
| | - D P Srivastava
- Cells & Behavior Unit, Department of Basic and Clinical Neuroscience, Institute of Psychiatry Psychology & Neuroscience, King’s College London, London, UK,MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK
| | - J Price
- Cells & Behavior Unit, Department of Basic and Clinical Neuroscience, Institute of Psychiatry Psychology & Neuroscience, King’s College London, London, UK,MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK,Division of Advanced Therapies, National Institute for Biological Standards and Control, Hertfordshire, UK,Cells & Behavior Unit, Department of Basic and Clinical Neuroscience, Institute of Psychiatry Psychology & Neuroscience, King’s College London, London SE5 9RT, UK. E-mail:
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36
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Na ES, De Jesús-Cortés H, Martinez-Rivera A, Kabir ZD, Wang J, Ramesh V, Onder Y, Rajadhyaksha AM, Monteggia LM, Pieper AA. D-cycloserine improves synaptic transmission in an animal model of Rett syndrome. PLoS One 2017; 12:e0183026. [PMID: 28813484 PMCID: PMC5559075 DOI: 10.1371/journal.pone.0183026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 07/30/2017] [Indexed: 01/24/2023] Open
Abstract
Rett syndrome (RTT), a leading cause of intellectual disability in girls, is predominantly caused by mutations in the X-linked gene MECP2. Disruption of Mecp2 in mice recapitulates major features of RTT, including neurobehavioral abnormalities, which can be reversed by re-expression of normal Mecp2. Thus, there is reason to believe that RTT could be amenable to therapeutic intervention throughout the lifespan of patients after the onset of symptoms. A common feature underlying neuropsychiatric disorders, including RTT, is altered synaptic function in the brain. Here, we show that Mecp2tm1.1Jae/y mice display lower presynaptic function as assessed by paired pulse ratio, as well as decreased long term potentiation (LTP) at hippocampal Schaffer–collateral-CA1 synapses. Treatment of Mecp2tm1.1Jae/y mice with D-cycloserine (DCS), an FDA-approved analog of the amino acid D-alanine with antibiotic and glycinergic activity, corrected the presynaptic but not LTP deficit without affecting deficient hippocampal BDNF levels. DCS treatment did, however, partially restore lower BDNF levels in the brain stem and striatum. Thus, treatment with DCS may mitigate the severity of some of the neurobehavioral symptoms experienced by patients with Rett syndrome.
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Affiliation(s)
- Elisa S. Na
- Department of Psychology & Philosophy, Texas Woman’s University, Denton, TX, United States of America
| | - Héctor De Jesús-Cortés
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, United States of America
| | - Arlene Martinez-Rivera
- Division of Pediatric Neurology, Department of Pediatrics, Weill Cornell Medicine, Cornell University, New York, NY, United States of America
- Weill Cornell Autism Research Program, Weill Cornell Medicine, Cornell University, New York, NY, United States of America
| | - Zeeba D. Kabir
- Division of Pediatric Neurology, Department of Pediatrics, Weill Cornell Medicine, Cornell University, New York, NY, United States of America
- Weill Cornell Autism Research Program, Weill Cornell Medicine, Cornell University, New York, NY, United States of America
| | - Jieqi Wang
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
| | - Vijayashree Ramesh
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX, United States of America
| | - Yasemin Onder
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX, United States of America
| | - Anjali M. Rajadhyaksha
- Division of Pediatric Neurology, Department of Pediatrics, Weill Cornell Medicine, Cornell University, New York, NY, United States of America
- Weill Cornell Autism Research Program, Weill Cornell Medicine, Cornell University, New York, NY, United States of America
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, Cornell University, New York, NY, United States of America
- * E-mail: (AMR); (LMM); (AAP)
| | - Lisa M. Monteggia
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX, United States of America
- * E-mail: (AMR); (LMM); (AAP)
| | - Andrew A. Pieper
- Weill Cornell Autism Research Program, Weill Cornell Medicine, Cornell University, New York, NY, United States of America
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Department of Neurology, University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Department of Free Radical and Radiation Biology, University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Department of Veterans Affairs, University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Pappajohn Biomedical Institute, University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- * E-mail: (AMR); (LMM); (AAP)
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37
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Altered visual cortical processing in a mouse model of MECP2 duplication syndrome. Sci Rep 2017; 7:6468. [PMID: 28743991 PMCID: PMC5526895 DOI: 10.1038/s41598-017-06916-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 06/21/2017] [Indexed: 12/27/2022] Open
Abstract
As an epigenetic modulator of gene expression, Methyl-CpG binding protein 2 (MeCP2) is essential for normal neurological function. Dysfunction of MeCP2 is associated with a variety of neurological disorders. MECP2 gene duplication in human causes neuropsychiatric symptoms such as mental retardation and autism. MeCP2 overexpression in mice results in neurobehavioural disorders, dendritic abnormalities, and synaptic defects. However, how gain of MeCP2 function influences cortical processing of sensory information remains unclear. In this study, we examined visual processing in a mouse model of MECP2 duplication syndrome (MECP2 Tg1 mouse) at 8 and 14 weeks, which were before and after the onset of behavioural symptoms, respectively. In vivo extracellular recordings from primary visual cortex (V1) showed that neurons in Tg1 mice at both adult ages preferred higher spatial frequencies (SFs) than those in wild-type (WT) littermate controls, and the semi-saturation contrasts of neurons were lower in Tg1 mice at 8 weeks but not at 14 weeks. Behavioural experiments showed that the performance for visual detection at high SFs and low contrasts was higher in MECP2 Tg1 mice. Thus, MeCP2 gain-of-function in mice leads to higher visual acuity and contrast sensitivity, both at the levels of cortical response and behavioural performance.
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Varodayan FP, Logrip ML, Roberto M. P/Q-type voltage-gated calcium channels mediate the ethanol and CRF sensitivity of central amygdala GABAergic synapses. Neuropharmacology 2017; 125:197-206. [PMID: 28734867 DOI: 10.1016/j.neuropharm.2017.07.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 07/14/2017] [Accepted: 07/17/2017] [Indexed: 01/09/2023]
Abstract
The central amygdala (CeA) GABAergic system is hypothesized to drive the development of alcohol dependence, due to its pivotal roles in the reinforcing actions of alcohol and the expression of negative emotion, anxiety and stress. Recent work has also identified an important role for the CeA corticotropin-releasing factor (CRF) system in the interaction between anxiety/stress and alcohol dependence. We have previously shown that acute alcohol and CRF each increase action potential-independent GABA release in the CeA via their actions at presynaptic CRF type 1 receptors (CRF1s); however, the shared mechanism employed by these two compounds requires further investigation. Here we report that acute alcohol interacts with the CRF/CRF1 system, such that CRF and alcohol act via presynaptic CRF1s and P/Q-type voltage-gated calcium channels to promote vesicular GABA release and that both compounds occlude the effects of each other at these synapses. Chronic alcohol exposure does not alter P/Q-type voltage-gated calcium channel membrane abundance or this CRF1/P/Q-type voltage-gated calcium channel mechanism of acute alcohol-induced GABA release, indicating that alcohol engages this molecular mechanism at CeA GABAergic synapses throughout the transition to dependence. Thus, P/Q-type voltage-gated calcium channels, like CRF1s, are key regulators of the effects of alcohol on GABAergic signaling in the CeA.
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Affiliation(s)
- F P Varodayan
- The Scripps Research Institute, Department of Neuroscience, La Jolla, CA 92037, USA.
| | - M L Logrip
- The Scripps Research Institute, Department of Neuroscience, La Jolla, CA 92037, USA
| | - M Roberto
- The Scripps Research Institute, Department of Neuroscience, La Jolla, CA 92037, USA
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39
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Gideons ES, Lin PY, Mahgoub M, Kavalali ET, Monteggia LM. Chronic lithium treatment elicits its antimanic effects via BDNF-TrkB dependent synaptic downscaling. eLife 2017; 6:e25480. [PMID: 28621662 PMCID: PMC5499943 DOI: 10.7554/elife.25480] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 06/07/2017] [Indexed: 12/27/2022] Open
Abstract
Lithium is widely used as a treatment for Bipolar Disorder although the molecular mechanisms that underlie its therapeutic effects are under debate. In this study, we show brain-derived neurotrophic factor (BDNF) is required for the antimanic-like effects of lithium but not the antidepressant-like effects in mice. We performed whole cell patch clamp recordings of hippocampal neurons to determine the impact of lithium on synaptic transmission that may underlie the behavioral effects. Lithium produced a significant decrease in α-amino-3-hydroxyl-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)-mediated miniature excitatory postsynaptic current (mEPSC) amplitudes due to postsynaptic homeostatic plasticity that was dependent on BDNF and its receptor tropomyosin receptor kinase B (TrkB). The decrease in AMPAR function was due to reduced surface expression of GluA1 subunits through dynamin-dependent endocytosis. Collectively, these findings demonstrate a requirement for BDNF in the antimanic action of lithium and identify enhanced dynamin-dependent endocytosis of AMPARs as a potential mechanism underlying the therapeutic effects of lithium.
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Affiliation(s)
- Erinn S Gideons
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, United States
| | - Pei-Yi Lin
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, United States
| | - Melissa Mahgoub
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, United States
| | - Ege T Kavalali
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, United States
| | - Lisa M Monteggia
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, United States
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40
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Lee E, Lee J, Kim E. Excitation/Inhibition Imbalance in Animal Models of Autism Spectrum Disorders. Biol Psychiatry 2017; 81:838-847. [PMID: 27450033 DOI: 10.1016/j.biopsych.2016.05.011] [Citation(s) in RCA: 302] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 05/02/2016] [Accepted: 05/16/2016] [Indexed: 12/19/2022]
Abstract
Imbalances between excitation and inhibition in synaptic transmission and neural circuits have been implicated in autism spectrum disorders. Excitation and inhibition imbalances are frequently observed in animal models of autism spectrum disorders, and their correction normalizes key autistic-like phenotypes in these animals. These results suggest that excitation and inhibition imbalances may contribute to the development and maintenance of autism spectrum disorders and represent an important therapeutic target.
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Affiliation(s)
- Eunee Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon, Korea
| | - Jiseok Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Korea
| | - Eunjoon Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon, Korea; Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Korea.
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41
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Tomasoni R, Morini R, Lopez-Atalaya JP, Corradini I, Canzi A, Rasile M, Mantovani C, Pozzi D, Garlanda C, Mantovani A, Menna E, Barco A, Matteoli M. Lack of IL-1R8 in neurons causes hyperactivation of IL-1 receptor pathway and induces MECP2-dependent synaptic defects. eLife 2017; 6. [PMID: 28347403 PMCID: PMC5370184 DOI: 10.7554/elife.21735] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 02/26/2017] [Indexed: 12/12/2022] Open
Abstract
Inflammation modifies risk and/or severity of a variety of brain diseases through still elusive molecular mechanisms. Here we show that hyperactivation of the interleukin 1 pathway, through either ablation of the interleukin 1 receptor 8 (IL-1R8, also known as SIGIRR or Tir8) or activation of IL-1R, leads to up-regulation of the mTOR pathway and increased levels of the epigenetic regulator MeCP2, bringing to disruption of dendritic spine morphology, synaptic plasticity and plasticity-related gene expression. Genetic correction of MeCP2 levels in IL-1R8 KO neurons rescues the synaptic defects. Pharmacological inhibition of IL-1R activation by Anakinra corrects transcriptional changes, restores MeCP2 levels and spine plasticity and ameliorates cognitive defects in IL-1R8 KO mice. By linking for the first time neuronal MeCP2, a key player in brain development, to immune activation and demonstrating that synaptic defects can be pharmacologically reversed, these data open the possibility for novel treatments of neurological diseases through the immune system modulation. DOI:http://dx.doi.org/10.7554/eLife.21735.001 Errors that occur while the brain is developing can lead to conditions such as autism and schizophrenia. They can also lead to rare disorders like Rett syndrome and MeCP2 duplication syndromes, which are characterized by severe cognitive and physical disabilities. Many people with these neurodevelopmental disorders have mutations in genes that encode proteins found at synapses, which are the junctions between neurons where the cells exchange information with one another. However, not everyone with these mutations develops a neurodevelopmental disorder, which indicates that other, non-genetic factors also play a part. One of the main non-genetic factors that can influence the risk and severity of neurodevelopmental disorders is inflammation of the brain. Inflammation is a normal part of the body’s immune response to threats such as invading microorganisms or tissue damage. However, abnormal activation of the immune system in early life can trigger excessive inflammation. This increases the risk of a neurodevelopmental disorder, but it is not clear exactly how it does so. Tomasoni et al. set out to test whether the missing link between inflammation and neurodevelopmental disorders might be damage to synapses. The experiments revealed that genetically modified mice with inflammation of the brain have abnormal synapses and are unable to learn properly. These mutant mice also have excessive levels of a protein that influences how synapses function called MeCP2, which is missing in the brains of people with Rett syndrome and abnormally increased in brains of patients affected by MeCP2 Duplication Syndrome. This is thus the first evidence that directly links inflammation of the brain to a synapse protein implicated in a disorder of brain development. Tomasoni et al. also found that a drug called anakinra – which is used to treat an inflammatory disease called rheumatoid arthritis – reduced levels of MeCP2 in the mutant mice and improved their performance in cognitive tasks. Together, these results raise the possibility that anti-inflammatory medications may be beneficial in the treatment of neurodevelopment disorders. DOI:http://dx.doi.org/10.7554/eLife.21735.002
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Affiliation(s)
- Romana Tomasoni
- IRCCS Humanitas, Rozzano, Italy.,Instituto de Neurociencias (Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas), Alicante, Spain
| | | | - Jose P Lopez-Atalaya
- Instituto de Neurociencias (Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas), Alicante, Spain
| | | | - Alice Canzi
- IRCCS Humanitas, Rozzano, Italy.,Hunimed University, Rozzano, Italy
| | - Marco Rasile
- IRCCS Humanitas, Rozzano, Italy.,Hunimed University, Rozzano, Italy
| | | | - Davide Pozzi
- IRCCS Humanitas, Rozzano, Italy.,Hunimed University, Rozzano, Italy
| | | | | | | | - Angel Barco
- Instituto de Neurociencias (Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas), Alicante, Spain
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Horvath PM, Kavalali ET, Monteggia LM. CRISPR/Cas9 system-mediated impairment of synaptobrevin/VAMP function in postmitotic hippocampal neurons. J Neurosci Methods 2017; 278:57-64. [PMID: 28025172 PMCID: PMC5505177 DOI: 10.1016/j.jneumeth.2016.12.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 11/09/2016] [Accepted: 12/22/2016] [Indexed: 12/25/2022]
Abstract
BACKGROUND The use of the CRISPR/Cas9 system is becoming widespread, however current studies have predominantly focused on dividing cells. It is currently unknown if CRISPR/Cas9 can be used in a postmitotic setting to examine non-cell autonomous/presynaptic phenotypes in the resulting genetically heterogeneous cell population. NEW METHOD A single CRISPR/Cas9 lentivirus was used to transfect a high percentage of primary cultured neurons and target synaptobrevin 2 (Syb2, also called VAMP2). RESULTS Primary hippocampal cultures infected with the Syb2 targeting virus displayed dramatic reductions in Syb2 protein and immunocytochemical staining. In many boutons Syb2 was completely undetected. These cultures recapitulated the known functional phenotypes of Syb2 knockout neurons, which are non-cell autonomous and presynaptic in origin, indicating that Syb2 was knocked out in a large fraction of neurons. COMPARISON WITH EXISTING METHOD(S) Previous methods used multiple viruses or sparse transfection methods and only examined cell autonomous or postsynaptic phenotypes. The current method demonstrates that the CRISPR/Cas9 system can be used to alter network dynamics by removing or lowering the target gene from a majority of cells in the culture. CONCLUSIONS A combination of CRISPR/Cas9 system and single high efficiency lentivirus infection can be used to examine non-cell autonomous and presynaptic phenotypes in postmitotic neurons.
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Affiliation(s)
- Patricia M Horvath
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Ege T Kavalali
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Physiology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Lisa M Monteggia
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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43
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Leonard H, Cobb S, Downs J. Clinical and biological progress over 50 years in Rett syndrome. Nat Rev Neurol 2016; 13:37-51. [PMID: 27934853 DOI: 10.1038/nrneurol.2016.186] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In the 50 years since Andreas Rett first described the syndrome that came to bear his name, and is now known to be caused by a mutation in the methyl-CpG-binding protein 2 (MECP2) gene, a compelling blend of astute clinical observations and clinical and laboratory research has substantially enhanced our understanding of this rare disorder. Here, we document the contributions of the early pioneers in Rett syndrome (RTT) research, and describe the evolution of knowledge in terms of diagnostic criteria, clinical variation, and the interplay with other Rett-related disorders. We provide a synthesis of what is known about the neurobiology of MeCP2, considering the lessons learned from both cell and animal models, and how they might inform future clinical trials. With a focus on the core criteria, we examine the relationships between genotype and clinical severity. We review current knowledge about the many comorbidities that occur in RTT, and how genotype may modify their presentation. We also acknowledge the important drivers that are accelerating this research programme, including the roles of research infrastructure, international collaboration and advocacy groups. Finally, we highlight the major milestones since 1966, and what they mean for the day-to-day lives of individuals with RTT and their families.
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Affiliation(s)
- Helen Leonard
- Telethon Kids Institute, 100 Roberts Road, Subiaco, Perth, Western Australia 6008, Australia
| | - Stuart Cobb
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK
| | - Jenny Downs
- Telethon Kids Institute, 100 Roberts Road, Subiaco, Perth, Western Australia 6008, Australia
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44
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Villani C, Sacchetti G, Bagnati R, Passoni A, Fusco F, Carli M, Invernizzi RW. Lovastatin fails to improve motor performance and survival in methyl-CpG-binding protein2-null mice. eLife 2016; 5:22409. [PMID: 27892851 PMCID: PMC5132339 DOI: 10.7554/elife.22409] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Accepted: 11/18/2016] [Indexed: 01/25/2023] Open
Abstract
Previous studies provided evidence for the alteration of brain cholesterol homeostasis in 129.Mecp2-null mice, an experimental model of Rett syndrome. The efficacy of statins in improving motor symptoms and prolonging survival of mutant mice suggested a potential role of statins in the therapy of Rett syndrome. In the present study, we show that Mecp2 deletion had no effect on brain and reduced serum cholesterol levels and lovastatin (1.5 mg/kg, twice weekly as in the previous study) had no effects on motor deficits and survival when Mecp2 deletion was expressed on a background strain (C57BL/6J; B6) differing from that used in the earlier study. These findings indicate that the effects of statins may be background specific and raise important issues to consider when contemplating clinical trials. The reduction of the brain cholesterol metabolite 24S-hydroxycholesterol (24S-OHC) found in B6.Mecp2-null mice suggests the occurrence of changes in brain cholesterol metabolism and the potential utility of using plasma levels of 24S-OHC as a biomarker of brain cholesterol homeostasis in RTT. DOI:http://dx.doi.org/10.7554/eLife.22409.001
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Affiliation(s)
- Claudia Villani
- Laboratory of Neurochemistry and Behaviour, Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy
| | - Giuseppina Sacchetti
- Laboratory of Neurochemistry and Behaviour, Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy
| | - Renzo Bagnati
- Analytical Instrumentation Unit, Department of Environmental Health Sciences, Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy
| | - Alice Passoni
- Analytical Instrumentation Unit, Department of Environmental Health Sciences, Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy
| | - Federica Fusco
- Genetics of Neurodegenerative Diseases Unit, Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy
| | - Mirjana Carli
- Laboratory of Neurochemistry and Behaviour, Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy
| | - Roberto William Invernizzi
- Laboratory of Neurochemistry and Behaviour, Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy
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45
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Ehrhart F, Coort SLM, Cirillo E, Smeets E, Evelo CT, Curfs LMG. Rett syndrome - biological pathways leading from MECP2 to disorder phenotypes. Orphanet J Rare Dis 2016; 11:158. [PMID: 27884167 PMCID: PMC5123333 DOI: 10.1186/s13023-016-0545-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 11/17/2016] [Indexed: 02/07/2023] Open
Abstract
Rett syndrome (RTT) is a rare disease but still one of the most abundant causes for intellectual disability in females. Typical symptoms are onset at month 6-18 after normal pre- and postnatal development, loss of acquired skills and severe intellectual disability. The type and severity of symptoms are individually highly different. A single mutation in one gene, coding for methyl-CpG-binding protein 2 (MECP2), is responsible for the disease. The most important action of MECP2 is regulating epigenetic imprinting and chromatin condensation, but MECP2 influences many different biological pathways on multiple levels although the molecular pathways from gene to phenotype are currently not fully understood. In this review the known changes in metabolite levels, gene expression and biological pathways in RTT are summarized, discussed how they are leading to some characteristic RTT phenotypes and therefore the gaps of knowledge are identified. Namely, which phenotypes have currently no mechanistic explanation leading back to MECP2 related pathways? As a result of this review the visualization of the biologic pathways showing MECP2 up- and downstream regulation was developed and published on WikiPathways which will serve as template for future omics data driven research. This pathway driven approach may serve as a use case for other rare diseases, too.
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Affiliation(s)
- Friederike Ehrhart
- Governor Kremers Centre - Rett Expertise Centre, Maastricht University Medical Center, Maastricht, The Netherlands. .,Department of Bioinformatics, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands.
| | - Susan L M Coort
- Department of Bioinformatics, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Elisa Cirillo
- Department of Bioinformatics, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Eric Smeets
- Governor Kremers Centre - Rett Expertise Centre, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Chris T Evelo
- Governor Kremers Centre - Rett Expertise Centre, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Bioinformatics, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Leopold M G Curfs
- Governor Kremers Centre - Rett Expertise Centre, Maastricht University Medical Center, Maastricht, The Netherlands
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46
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Constantin L. The Role of MicroRNAs in Cerebellar Development and Autism Spectrum Disorder During Embryogenesis. Mol Neurobiol 2016; 54:6944-6959. [PMID: 27774573 DOI: 10.1007/s12035-016-0220-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 10/12/2016] [Indexed: 02/03/2023]
Abstract
MicroRNAs (miRNAs) are a class of small non-coding RNA molecules with wide-ranging and subtle effects on protein production. Their activity during the development of the cerebellum provides a valuable exemplar of how non-coding molecules may assist the development and function of the central nervous system and drive neurodevelopmental disorders. Three distinct aspects of miRNA contribution to early cerebellar development will here be reviewed. Aspects are the establishment of the cerebellar anlage, the generation and maturation of at least two principal cell types of the developing cerebellar microcircuit, and the etiology and early progression of autism spectrum disorder. It will be argued here that the autism spectrum is an adept model to explore miRNA impact on the cognitive and affective processes that descend from the developing cerebellum.
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Affiliation(s)
- Lena Constantin
- School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, 4072, Australia. .,Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia.
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47
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Mahgoub M, Adachi M, Suzuki K, Liu X, Kavalali ET, Chahrour MH, Monteggia LM. MeCP2 and histone deacetylases 1 and 2 in dorsal striatum collectively suppress repetitive behaviors. Nat Neurosci 2016; 19:1506-1512. [PMID: 27668390 PMCID: PMC5083208 DOI: 10.1038/nn.4395] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 08/25/2016] [Indexed: 02/08/2023]
Abstract
Class I histone deacetylases (HDACs), HDAC1 and HDAC2 often associate together in protein complexes with transcriptional factors such as methyl-CpG-binding protein 2 (MeCP2). Given their high degree of sequence identity, we examined the functional redundancy of HDAC1 and HDAC2 in mature brain. We demonstrate that postnatal forebrain-specific deletion of both HDAC1 and HDAC2 in mice impacts neuronal survival and results in an excessive grooming phenotype caused by dysregulation of the obsessive-compulsive disorder-implicated gene SAP90/PSD-95-associated protein 3 (SAPAP3) in striatum. Moreover, HDAC1- and HDAC2-dependent regulation of SAPAP3 expression requires Mecp2, the gene involved in the pathophysiology of Rett syndrome. We show that postnatal forebrain-specific deletion of Mecp2 causes excessive grooming, which is rescued by restoring striatal Sapap3 expression. Our results provide novel insight into the upstream regulation of SAPAP3, and establish the essential role of striatal HDAC1, HDAC2, and MeCP2 for suppression of repetitive behaviors.
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Affiliation(s)
- Melissa Mahgoub
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Megumi Adachi
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Kanzo Suzuki
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Xihui Liu
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Ege T Kavalali
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Maria H Chahrour
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Lisa M Monteggia
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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48
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Suryavanshi PS, Gupta SC, Yadav R, Kesherwani V, Liu J, Dravid SM. Glutamate Delta-1 Receptor Regulates Metabotropic Glutamate Receptor 5 Signaling in the Hippocampus. Mol Pharmacol 2016; 90:96-105. [PMID: 27231330 DOI: 10.1124/mol.116.104786] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 05/24/2016] [Indexed: 11/22/2022] Open
Abstract
The delta family of ionotropic glutamate receptors consists of glutamate delta-1 (GluD1) and glutamate delta-2 receptors. We have previously shown that GluD1 knockout mice exhibit features of developmental delay, including impaired spine pruning and switch in the N-methyl-D-aspartate receptor subunit, which are relevant to autism and other neurodevelopmental disorders. Here, we identified a novel role of GluD1 in regulating metabotropic glutamate receptor 5 (mGlu5) signaling in the hippocampus. Immunohistochemical analysis demonstrated colocalization of mGlu5 with GluD1 punctas in the hippocampus. Additionally, GluD1 protein coimmunoprecipitated with mGlu5 in the hippocampal membrane fraction, as well as when overexpressed in human embryonic kidney 293 cells, demonstrating that GluD1 and mGlu5 may cooperate in a signaling complex. The interaction of mGlu5 with scaffold protein effector Homer, which regulates mechanistic target of rapamycin (mTOR) signaling, was abnormal both under basal conditions and in response to mGlu1/5 agonist (RS)-3,5-dihydroxyphenylglycine (DHPG) in GluD1 knockout mice. The basal levels of phosphorylated mTOR and protein kinase B, the signaling proteins downstream of mGlu5 activation, were higher in GluD1 knockout mice, and no further increase was induced by DHPG. We also observed higher basal protein translation and an absence of DHPG-induced increase in GluD1 knockout mice. In accordance with a role of mGlu5-mediated mTOR signaling in synaptic plasticity, DHPG-induced internalization of surface α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunits was impaired in the GluD1 knockout mice. These results demonstrate that GluD1 interacts with mGlu5, and loss of GluD1 impairs normal mGlu5 signaling potentially by dysregulating coupling to its effector. These studies identify a novel role of the enigmatic GluD1 subunit in hippocampal function.
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Affiliation(s)
| | - Subhash C Gupta
- Department of Pharmacology, Creighton University, Omaha, Nebraska
| | - Roopali Yadav
- Department of Pharmacology, Creighton University, Omaha, Nebraska
| | - Varun Kesherwani
- Department of Pharmacology, Creighton University, Omaha, Nebraska
| | - Jinxu Liu
- Department of Pharmacology, Creighton University, Omaha, Nebraska
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49
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Cell-Specific Regulation of N-Methyl-D-Aspartate Receptor Maturation by Mecp2 in Cortical Circuits. Biol Psychiatry 2016; 79:746-754. [PMID: 26185009 PMCID: PMC4670611 DOI: 10.1016/j.biopsych.2015.05.018] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 04/29/2015] [Accepted: 05/20/2015] [Indexed: 11/20/2022]
Abstract
BACKGROUND Early postnatal experience shapes N-methyl-D-aspartate receptor (NMDAR) subunit composition and kinetics at excitatory synapses onto pyramidal cells; however, little is known about NMDAR maturation onto inhibitory interneurons. METHODS We combined whole-cell patch clamp recordings (n = 440) of NMDAR-mediated currents from layer-4-to-layer-2/3 synapses onto pyramidal and green fluorescent protein labeled parvalbumin-positive (PV) interneurons in visual cortex at three developmental ages (15, 30, and 45 postnatal days) with array tomography three-dimensional reconstructions of NMDAR subunits GluN2A- and GluN2B-positive synapses onto PV cells. RESULTS We show that the trajectory of the NMDAR subunit switch is slower in PV interneurons than in excitatory pyramidal cells in visual cortex. Notably, this differential time course is reversed in the absence of methyl-CpG-binding protein, MECP2, the molecular basis for cognitive decline in Rett syndrome and some cases of autism. Additional genetic reduction of GluN2A subunits, which prevents regression of vision in Mecp2-knockout mice, specifically rescues the accelerated NMDAR maturation in PV cells. CONCLUSIONS We demonstrate 1) the time course of NMDAR maturation is cell-type specific, and 2) a new cell-type specific role for Mecp2 in the development of NMDAR subunit composition. Reducing GluN2A expression in Mecp2-knockout mice, which prevents the decline in visual cortical function, also prevents the premature NMDAR maturation in PV cells. Thus, circuit-based therapies targeting NMDAR subunit composition on PV cells may provide novel treatments for Rett syndrome.
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50
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Developmental Dynamics of Rett Syndrome. Neural Plast 2016; 2016:6154080. [PMID: 26942018 PMCID: PMC4752981 DOI: 10.1155/2016/6154080] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Revised: 12/23/2015] [Accepted: 12/31/2015] [Indexed: 12/31/2022] Open
Abstract
Rett Syndrome was long considered to be simply a disorder of postnatal development, with phenotypes that manifest only late in development and into adulthood. A variety of recent evidence demonstrates that the phenotypes of Rett Syndrome are present at the earliest stages of brain development, including developmental stages that define neurogenesis, migration, and patterning in addition to stages of synaptic and circuit development and plasticity. These phenotypes arise from the pleotropic effects of MeCP2, which is expressed very early in neuronal progenitors and continues to be expressed into adulthood. The effects of MeCP2 are mediated by diverse signaling, transcriptional, and epigenetic mechanisms. Attempts to reverse the effects of Rett Syndrome need to take into account the developmental dynamics and temporal impact of MeCP2 loss.
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