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Audouard E, Khefif N, Gillet-Legrand B, Nobilleau F, Bouazizi O, Stanga S, Despres G, Alves S, Lamazière A, Cartier N, Piguet F. Modulation of Brain Cholesterol Metabolism through CYP46A1 Overexpression for Rett Syndrome. Pharmaceutics 2024; 16:756. [PMID: 38931878 PMCID: PMC11207948 DOI: 10.3390/pharmaceutics16060756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 05/27/2024] [Accepted: 05/29/2024] [Indexed: 06/28/2024] Open
Abstract
Rett syndrome (RTT) is a rare neurodevelopmental disorder caused by mutation in the X-linked gene methyl-CpG-binding protein 2 (Mecp2), a ubiquitously expressed transcriptional regulator. RTT results in mental retardation and developmental regression that affects approximately 1 in 10,000 females. Currently, there is no curative treatment for RTT. Thus, it is crucial to develop new therapeutic approaches for children suffering from RTT. Several studies suggested that RTT is linked with defects in cholesterol homeostasis, but for the first time, therapeutic evaluation is carried out by modulating this pathway. Moreover, AAV-based CYP46A1 overexpression, the enzyme involved in cholesterol pathway, has been demonstrated to be efficient in several neurodegenerative diseases. Based on these data, we strongly believe that CYP46A1 could be a relevant therapeutic target for RTT. Herein, we evaluated the effects of intravenous AAVPHP.eB-hCYP46A1-HA delivery in male and female Mecp2-deficient mice. The applied AAVPHP.eB-hCYP46A1 transduced essential neurons of the central nervous system (CNS). CYP46A1 overexpression alleviates behavioral alterations in both male and female Mecp2 knockout mice and extends the lifespan in Mecp2-deficient males. Several parameters related to cholesterol pathway are improved and correction of mitochondrial activity is demonstrated in treated mice, which highlighted the clear therapeutic benefit of CYP46A1 through the neuroprotection effect. IV delivery of AAVPHP.eB-CYP46A1 is perfectly well tolerated with no inflammation observed in the CNS of the treated mice. Altogether, our results strongly suggest that CYP46A1 is a relevant target and overexpression could alleviate the phenotype of Rett patients.
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Affiliation(s)
- Emilie Audouard
- TIDU GENOV, Institut du Cerveau, ICM, F-75013 Paris, France;
- Institut du Cerveau, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, F-75013 Paris, France (B.G.-L.); (S.A.)
| | - Nicolas Khefif
- Institut du Cerveau, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, F-75013 Paris, France (B.G.-L.); (S.A.)
| | - Béatrix Gillet-Legrand
- Institut du Cerveau, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, F-75013 Paris, France (B.G.-L.); (S.A.)
| | - Fanny Nobilleau
- Institut du Cerveau, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, F-75013 Paris, France (B.G.-L.); (S.A.)
| | - Ouafa Bouazizi
- Institut du Cerveau, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, F-75013 Paris, France (B.G.-L.); (S.A.)
| | - Serena Stanga
- Neuroscience Institute Cavalieri Ottolenghi, 10043 Orbassano, Italy
- Department of Neuroscience Rita Levi Montalcini, University of Turin, 10126 Turin, Italy
| | - Gaëtan Despres
- Saint Antoine Research Center, INSERM UMR 938, Département de Métabolomique Clinique, Hôpital Saint Antoine, AP-HP Sorbonne Université, F-75013 Paris, France
| | - Sandro Alves
- Institut du Cerveau, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, F-75013 Paris, France (B.G.-L.); (S.A.)
| | - Antonin Lamazière
- Saint Antoine Research Center, INSERM UMR 938, Département de Métabolomique Clinique, Hôpital Saint Antoine, AP-HP Sorbonne Université, F-75013 Paris, France
| | - Nathalie Cartier
- Institut du Cerveau, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, F-75013 Paris, France (B.G.-L.); (S.A.)
| | - Françoise Piguet
- TIDU GENOV, Institut du Cerveau, ICM, F-75013 Paris, France;
- Institut du Cerveau, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, F-75013 Paris, France (B.G.-L.); (S.A.)
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van der Heijden ME. Converging and Diverging Cerebellar Pathways for Motor and Social Behaviors in Mice. CEREBELLUM (LONDON, ENGLAND) 2024:10.1007/s12311-024-01706-w. [PMID: 38780757 DOI: 10.1007/s12311-024-01706-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/17/2024] [Indexed: 05/25/2024]
Abstract
Evidence from clinical and preclinical studies has shown that the cerebellum contributes to cognitive functions, including social behaviors. Now that the cerebellum's role in a wider range of behaviors has been confirmed, the question arises whether the cerebellum contributes to social behaviors via the same mechanisms with which it modulates movements. This review seeks to answer whether the cerebellum guides motor and social behaviors through identical pathways. It focuses on studies in which cerebellar cells, synapses, or genes are manipulated in a cell-type specific manner followed by testing of the effects on social and motor behaviors. These studies show that both anatomically restricted and cerebellar cortex-wide manipulations can lead to social impairments without abnormal motor control, and vice versa. These studies suggest that the cerebellum employs different cellular, synaptic, and molecular pathways for social and motor behaviors. Future studies warrant a focus on the diverging mechanisms by which the cerebellum contributes to a wide range of neural functions.
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Affiliation(s)
- Meike E van der Heijden
- Fralin Biomedical Research Institute, Virginia Tech Carilion, Roanoke, VA, USA.
- Center for Neurobiology Research, Virginia Tech Carilion, Roanoke, VA, USA.
- School of Neuroscience, Virginia Tech, Blacksburg, VA, USA.
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3
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Prati JM, Pontes-Silva A, Gianlorenço ACL. The cerebellum and its connections to other brain structures involved in motor and non-motor functions: A comprehensive review. Behav Brain Res 2024; 465:114933. [PMID: 38458437 DOI: 10.1016/j.bbr.2024.114933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 02/28/2024] [Accepted: 02/29/2024] [Indexed: 03/10/2024]
Abstract
The cerebellum has a large network of neurons that communicate with several brain structures and participate in different functions. Recent studies have demonstrated that the cerebellum is not only associated with motor functions but also participates in several non-motor functions. It is suggested that the cerebellum can modulate behavior through many connections with different nervous system structures in motor, sensory, cognitive, autonomic, and emotional processes. Recently, a growing number of clinical and experimental studies support this theory and provide further evidence. In light of recent findings, a comprehensive review is needed to summarize the knowledge on the influence of the cerebellum on the processing of different functions. Therefore, the aim of this review was to describe the neuroanatomical aspects of the activation of the cerebellum and its connections with other structures of the central nervous system in different behaviors.
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Affiliation(s)
- José Mário Prati
- Postgraduate Program in Physical Therapy, Department of Physical Therapy, Universidade Federal de São Carlos, São Carlos, SP, Brazil.
| | - André Pontes-Silva
- Postgraduate Program in Physical Therapy, Department of Physical Therapy, Universidade Federal de São Carlos, São Carlos, SP, Brazil
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4
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Xu FX, Wang XT, Cai XY, Liu JY, Guo JW, Yang F, Chen W, Schonewille M, De Zeeuw C, Zhou L, Shen Y. Purkinje-cell-specific MeCP2 deficiency leads to motor deficits and autistic-like behavior due to aberrations in PTP1B-TrkB-SK signaling. Cell Rep 2023; 42:113559. [PMID: 38100348 DOI: 10.1016/j.celrep.2023.113559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 10/05/2023] [Accepted: 11/22/2023] [Indexed: 12/17/2023] Open
Abstract
Patients with Rett syndrome suffer from a loss-of-function mutation of the Mecp2 gene, which results in various symptoms including autistic traits and motor deficits. Deletion of Mecp2 in the brain mimics part of these symptoms, but the specific function of methyl-CpG-binding protein 2 (MeCP2) in the cerebellum remains to be elucidated. Here, we demonstrate that Mecp2 deletion in Purkinje cells (PCs) reduces their intrinsic excitability through a signaling pathway comprising the small-conductance calcium-activated potassium channel PTP1B and TrkB, the receptor of brain-derived neurotrophic factor. Aberration of this cascade, in turn, leads to autistic-like behaviors as well as reduced vestibulocerebellar motor learning. Interestingly, increasing activity of TrkB in PCs is sufficient to rescue PC dysfunction and abnormal motor and non-motor behaviors caused by Mecp2 deficiency. Our findings highlight how PC dysfunction may contribute to Rett syndrome, providing insight into the underlying mechanism and paving the way for rational therapeutic designs.
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Affiliation(s)
- Fang-Xiao Xu
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310000, China
| | - Xin-Tai Wang
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310000, China; Institute of Life Sciences, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 311121, China
| | - Xin-Yu Cai
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310000, China
| | - Jia-Yu Liu
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310000, China
| | - Jing-Wen Guo
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310000, China
| | - Fan Yang
- Department of Biophysics, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Wei Chen
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310000, China
| | - Martijn Schonewille
- Department of Neuroscience, Erasmus University Medical Center, 3000 DR Rotterdam, the Netherlands
| | - Chris De Zeeuw
- Department of Neuroscience, Erasmus University Medical Center, 3000 DR Rotterdam, the Netherlands; The Netherlands Institute for Neuroscience, Royal Dutch Academy of Arts and Science, 1105 CA Amsterdam, the Netherlands.
| | - Lin Zhou
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310000, China.
| | - Ying Shen
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310000, China; International Institutes of Medicine, Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China; Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou 310000, China.
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Sadhu C, Lyons C, Oh J, Jagadeeswaran I, Gray SJ, Sinnett SE. The Efficacy of a Human-Ready mini MECP2 Gene Therapy in a Pre-Clinical Model of Rett Syndrome. Genes (Basel) 2023; 15:31. [PMID: 38254921 PMCID: PMC10815157 DOI: 10.3390/genes15010031] [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: 11/14/2023] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 01/24/2024] Open
Abstract
Inactivating mutations and the duplication of methyl-CpG binding protein 2 (MeCP2), respectively, mediate Rett syndrome (RTT) and MECP2 duplication syndrome. These disorders underscore the conceptual dose-dependent risk posed by MECP2 gene therapy for mosaic RTT patients. Recently, a miRNA-Responsive Autoregulatory Element (miRARE) mitigated the dose-dependent toxicity posed by self-complementary adeno-associated viral vector serotype 9 (AAV9) miniMECP2 gene therapy (scAAV9/miniMECP2-myc) in mice. Here, we report an efficacy assessment for the human-ready version of this regulated gene therapy (TSHA-102) in male Mecp2-/y knockout (KO) mice after intracerebroventricular (ICV) administration at postnatal day 2 (P2) and after intrathecal (IT) administration at P7, P14 (±immunosuppression), and P28 (±immunosuppression). We also report qPCR studies on KO mice treated at P7-P35; protein analyses in KO mice treated at P38; and a survival safety study in female adult Mecp2-/+ mice. In KO mice, TSHA-102 improved respiration, weight, and survival across multiple doses and treatment ages. TSHA-102 significantly improved the front average stance and swing times relative to the front average stride time after P14 administration of the highest dose for that treatment age. Viral genomic DNA and miniMECP2 mRNA were present in the CNS. MiniMeCP2 protein expression was higher in the KO spinal cord compared to the brain. In female mice, TSHA-102 permitted survivals that were similar to those of vehicle-treated controls. In all, these pivotal data helped to support the regulatory approval to initiate a clinical trial for TSHA-102 in RTT patients (clinical trial identifier number NCT05606614).
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Affiliation(s)
- Chanchal Sadhu
- Formerly of Taysha Gene Therapies, Dallas, TX 75247, USA
| | - Christopher Lyons
- Formerly of the Department of Pediatrics, University of Texas Southwestern Medical Center (UTSWMC), Dallas, TX 75390, USA
| | - Jiyoung Oh
- Department of Pediatrics, University of Texas Southwestern Medical Center (UTSWMC), Dallas, TX 75390, USA
| | - Indumathy Jagadeeswaran
- Department of Pediatrics, University of Texas Southwestern Medical Center (UTSWMC), Dallas, TX 75390, USA
| | - Steven J. Gray
- Department of Pediatrics, University of Texas Southwestern Medical Center (UTSWMC), Dallas, TX 75390, USA
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center (UTSWMC), Dallas, TX 75390, USA
- Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center (UTSWMC), Dallas, TX 75390, USA
| | - Sarah E. Sinnett
- Department of Pediatrics, University of Texas Southwestern Medical Center (UTSWMC), Dallas, TX 75390, USA
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center (UTSWMC), Dallas, TX 75390, USA
- Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center (UTSWMC), Dallas, TX 75390, USA
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Musokhranova U, Grau C, Vergara C, Rodríguez-Pascau L, Xiol C, Castells AA, Alcántara S, Rodríguez-Pombo P, Pizcueta P, Martinell M, García-Cazorla A, Oyarzábal A. Mitochondrial modulation with leriglitazone as a potential treatment for Rett syndrome. J Transl Med 2023; 21:756. [PMID: 37884937 PMCID: PMC10601217 DOI: 10.1186/s12967-023-04622-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 10/12/2023] [Indexed: 10/28/2023] Open
Abstract
BACKGROUND Rett syndrome is a neuropediatric disease occurring due to mutations in MECP2 and characterized by a regression in the neuronal development following a normal postnatal growth, which results in the loss of acquired capabilities such as speech or purposeful usage of hands. While altered neurotransmission and brain development are the center of its pathophysiology, alterations in mitochondrial performance have been previously outlined, shaping it as an attractive target for the disease treatment. METHODS We have thoroughly described mitochondrial performance in two Rett models, patients' primary fibroblasts and female Mecp2tm1.1Bird-/+ mice brain, discriminating between different brain areas. The characterization was made according to their bioenergetics function, oxidative stress, network dynamics or ultrastructure. Building on that, we have studied the effect of leriglitazone, a PPARγ agonist, in the modulation of mitochondrial performance. For that, we treated Rett female mice with 75 mg/kg/day leriglitazone from weaning until sacrifice at 7 months, studying both the mitochondrial performance changes and their consequences on the mice phenotype. Finally, we studied its effect on neuroinflammation based on the presence of reactive glia by immunohistochemistry and through a cytokine panel. RESULTS We have described mitochondrial alterations in Rett fibroblasts regarding both shape and bioenergetic functions, as they displayed less interconnected and shorter mitochondria and reduced ATP production along with increased oxidative stress. The bioenergetic alterations were recalled in Rett mice models, being especially significant in cerebellum, already detectable in pre-symptomatic stages. Treatment with leriglitazone recovered the bioenergetic alterations both in Rett fibroblasts and female mice and exerted an anti-inflammatory effect in the latest, resulting in the amelioration of the mice phenotype both in general condition and exploratory activity. CONCLUSIONS Our studies confirm the mitochondrial dysfunction in Rett syndrome, setting the differences through brain areas and disease stages. Its modulation through leriglitazone is a potential treatment for this disorder, along with other diseases with mitochondrial involvement. This work constitutes the preclinical necessary evidence to lead to a clinical trial.
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Affiliation(s)
- Uliana Musokhranova
- Synaptic Metabolism and Personalized Therapies Lab, Department of Neurology and MetabERN, Institut de Recerca Sant Joan de Déu, 39-57 Santa Rosa Street, Esplugues de Llobregat , 08950, Barcelona, Spain
| | - Cristina Grau
- Synaptic Metabolism and Personalized Therapies Lab, Department of Neurology and MetabERN, Institut de Recerca Sant Joan de Déu, 39-57 Santa Rosa Street, Esplugues de Llobregat , 08950, Barcelona, Spain
| | | | | | - Clara Xiol
- Department of Medical Genetics, Institut de Recerca Pediàtrica, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Alba A Castells
- Neural Development Lab, Departament de Patologia i Terapèutica Experimental, Institut de Neurociències, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Soledad Alcántara
- Neural Development Lab, Departament de Patologia i Terapèutica Experimental, Institut de Neurociències, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Pilar Rodríguez-Pombo
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular Severo Ochoa, CBM-CSIC, Departamento de Biología Molecular, Institute for Molecular Biology-IUBM, Universidad Autónoma Madrid, IDIPAZ, Madrid, Spain
- CIBERER-Spanish Biomedical Research Centre in Rare Diseases, Madrid, Spain
| | | | - Marc Martinell
- Minoryx Therapeutics BE S.A., Gosselies, Charleroi, Belgium
- Minoryx Therapeutics S.L., Barcelona, Spain
| | - Angels García-Cazorla
- Synaptic Metabolism and Personalized Therapies Lab, Department of Neurology and MetabERN, Institut de Recerca Sant Joan de Déu, 39-57 Santa Rosa Street, Esplugues de Llobregat , 08950, Barcelona, Spain
- CIBERER-Spanish Biomedical Research Centre in Rare Diseases, Madrid, Spain
| | - Alfonso Oyarzábal
- Synaptic Metabolism and Personalized Therapies Lab, Department of Neurology and MetabERN, Institut de Recerca Sant Joan de Déu, 39-57 Santa Rosa Street, Esplugues de Llobregat , 08950, Barcelona, Spain.
- CIBERER-Spanish Biomedical Research Centre in Rare Diseases, Madrid, Spain.
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Palmieri M, Pozzer D, Landsberger N. Advanced genetic therapies for the treatment of Rett syndrome: state of the art and future perspectives. Front Neurosci 2023; 17:1172805. [PMID: 37304036 PMCID: PMC10248472 DOI: 10.3389/fnins.2023.1172805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/02/2023] [Indexed: 06/13/2023] Open
Abstract
Loss and gain of functions mutations in the X-linked MECP2 (methyl-CpG-binding protein 2) gene are responsible for a set of generally severe neurological disorders that can affect both genders. In particular, Mecp2 deficiency is mainly associated with Rett syndrome (RTT) in girls, while duplication of the MECP2 gene leads, mainly in boys, to the MECP2 duplication syndrome (MDS). No cure is currently available for MECP2 related disorders. However, several studies have reported that by re-expressing the wild-type gene is possible to restore defective phenotypes of Mecp2 null animals. This proof of principle endorsed many laboratories to search for novel therapeutic strategies to cure RTT. Besides pharmacological approaches aimed at modulating MeCP2-downstream pathways, genetic targeting of MECP2 or its transcript have been largely proposed. Remarkably, two studies focused on augmentative gene therapy were recently approved for clinical trials. Both use molecular strategies to well-control gene dosage. Notably, the recent development of genome editing technologies has opened an alternative way to specifically target MECP2 without altering its physiological levels. Other attractive approaches exclusively applicable for nonsense mutations are the translational read-through (TR) and t-RNA suppressor therapy. Reactivation of the MECP2 locus on the silent X chromosome represents another valid choice for the disease. In this article, we intend to review the most recent genetic interventions for the treatment of RTT, describing the current state of the art, and the related advantages and concerns. We will also discuss the possible application of other advanced therapies, based on molecular delivery through nanoparticles, already proposed for other neurological disorders but still not tested in RTT.
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Affiliation(s)
- Michela Palmieri
- Rett Research Unit, Division of Neuroscience, San Raffaele Hospital (IRCCS), Milan, Italy
| | - Diego Pozzer
- Rett Research Unit, Division of Neuroscience, San Raffaele Hospital (IRCCS), Milan, Italy
| | - Nicoletta Landsberger
- Rett Research Unit, Division of Neuroscience, San Raffaele Hospital (IRCCS), Milan, Italy
- Department of Medical Biotechnology and Translational Medicine, Faculty of Medicine and Surgery, University of Milan, Milan, Italy
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Carli S, Chaabane L, De Rocco G, Albizzati E, Sormonta I, Calligaro S, Bonizzi P, Frasca A, Landsberger N. A comprehensive longitudinal study of magnetic resonance imaging identifies novel features of the Mecp2 deficient mouse brain. Neurobiol Dis 2023; 180:106083. [PMID: 36931532 DOI: 10.1016/j.nbd.2023.106083] [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: 12/13/2022] [Revised: 02/17/2023] [Accepted: 03/13/2023] [Indexed: 03/17/2023] Open
Abstract
Rett syndrome (RTT) is a X-linked neurodevelopmental disorder which represents the leading cause of severe incurable intellectual disability in females worldwide. The vast majority of RTT cases are caused by mutations in the X-linked MECP2 gene, and preclinical studies on RTT largely benefit from the use of mouse models of Mecp2, which present a broad spectrum of symptoms phenocopying those manifested by RTT patients. Neurons represent the core targets of the pathology; however, neuroanatomical abnormalities that regionally characterize the Mecp2 deficient mammalian brain remain ill-defined. Neuroimaging techniques, such as MRI and MRS, represent a key approach for assessing in vivo anatomic and metabolic changes in brain. Being non-invasive, these analyses also permit to investigate how the disease progresses over time through longitudinal studies. To foster the biological comprehension of RTT and identify useful biomarkers, we have performed a thorough in vivo longitudinal study of MRI and MRS in Mecp2 deficient mouse brains. Analyses were performed on both genders of two different mouse models of RTT, using an automatic atlas-based segmentation tool that permitted to obtain a detailed and unbiased description of the whole RTT mouse brain. We found that the most robust alteration of the RTT brain consists in an overall reduction of the brain volume. Accordingly, Mecp2 deficiency generally delays brain growth, eventually leading, in heterozygous older animals, to stagnation and/or contraction. Most but not all brain regions participate in the observed deficiency in brain size; similarly, the volumetric defect progresses diversely in different brain areas also depending on the specific Mecp2 genetic lesion and gender. Interestingly, in some regions volumetric defects anticipate overt symptoms, possibly revealing where the pathology originates and providing a useful biomarker for assessing drug efficacy in pre-clinical studies.
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Affiliation(s)
- Sara Carli
- Neuroscience Division, IRCCS San Raffaele Scientific Institute, Milan I-20132, Italy.
| | - Linda Chaabane
- Institute of Experimental Neurology (INSPE) and Experimental Imaging Center (CIS), IRCCS San Raffaele Scientific Institute, Milan I-20132, Italy.
| | - Giuseppina De Rocco
- Neuroscience Division, IRCCS San Raffaele Scientific Institute, Milan I-20132, Italy; Department of Medical Biotechnology and Translational Medicine, University of Milan, Segrate (Milan) I-20090, Italy.
| | - Elena Albizzati
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Segrate (Milan) I-20090, Italy.
| | - Irene Sormonta
- Neuroscience Division, IRCCS San Raffaele Scientific Institute, Milan I-20132, Italy.
| | - Stefano Calligaro
- Neuroscience Division, IRCCS San Raffaele Scientific Institute, Milan I-20132, Italy.
| | - Pietro Bonizzi
- Department of Advanced Computing Sciences, Maastricht University, Maastricht, the Netherlands.
| | - Angelisa Frasca
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Segrate (Milan) I-20090, Italy.
| | - Nicoletta Landsberger
- Neuroscience Division, IRCCS San Raffaele Scientific Institute, Milan I-20132, Italy; Department of Medical Biotechnology and Translational Medicine, University of Milan, Segrate (Milan) I-20090, Italy.
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9
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Deficits in Cerebellum-Dependent Learning and Cerebellar Morphology in Male and Female BTBR Autism Model Mice. NEUROSCI 2022. [DOI: 10.3390/neurosci3040045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Recently, there has been increased interest in the role of the cerebellum in autism spectrum disorder (ASD). To better understand the pathophysiological role of the cerebellum in ASD, it is necessary to have a variety of mouse models that have face validity for cerebellar disruption in humans. Here, we add to the literature on the cerebellum in mouse models of autism with the characterization of the cerebellum in the idiopathic BTBR T + Itpr3tf/J (BTBR) inbred mouse strain, which has behavioral phenotypes that are reminiscent of ASD in patients. When we examined both male and female BTBR mice in comparison to C57BL/6J (C57) controls, we noted that both sexes of BTBR mice showed motor coordination deficits characteristic of cerebellar dysfunction, but only the male mice showed differences in delay eyeblink conditioning, a cerebellum-dependent learning task that is known to be disrupted in ASD patients. Both male and female BTBR mice showed considerable expansion of, and abnormal foliation in, the cerebellum vermis—including a significant expansion of specific lobules in the anterior cerebellum. In addition, we found a slight but significant decrease in Purkinje cell density in both male and female BTBR mice, irrespective of the lobule. Finally, there was a marked reduction of Purkinje cell dendritic spine density in both male and female BTBR mice. These findings suggest that, for the most part, the BTBR mouse model phenocopies many of the characteristics of the subpopulation of ASD patients that have a hypertrophic cerebellum. We discuss the significance of strain differences in the cerebellum as well as the importance of this first effort to identify both similarities and differences between male and female BTBR mice with regard to the cerebellum.
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10
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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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Mapelli L, Soda T, D’Angelo E, Prestori F. The Cerebellar Involvement in Autism Spectrum Disorders: From the Social Brain to Mouse Models. Int J Mol Sci 2022; 23:ijms23073894. [PMID: 35409253 PMCID: PMC8998980 DOI: 10.3390/ijms23073894] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 02/04/2023] Open
Abstract
Autism spectrum disorders (ASD) are pervasive neurodevelopmental disorders that include a variety of forms and clinical phenotypes. This heterogeneity complicates the clinical and experimental approaches to ASD etiology and pathophysiology. To date, a unifying theory of these diseases is still missing. Nevertheless, the intense work of researchers and clinicians in the last decades has identified some ASD hallmarks and the primary brain areas involved. Not surprisingly, the areas that are part of the so-called “social brain”, and those strictly connected to them, were found to be crucial, such as the prefrontal cortex, amygdala, hippocampus, limbic system, and dopaminergic pathways. With the recent acknowledgment of the cerebellar contribution to cognitive functions and the social brain, its involvement in ASD has become unmistakable, though its extent is still to be elucidated. In most cases, significant advances were made possible by recent technological developments in structural/functional assessment of the human brain and by using mouse models of ASD. Mouse models are an invaluable tool to get insights into the molecular and cellular counterparts of the disease, acting on the specific genetic background generating ASD-like phenotype. Given the multifaceted nature of ASD and related studies, it is often difficult to navigate the literature and limit the huge content to specific questions. This review fulfills the need for an organized, clear, and state-of-the-art perspective on cerebellar involvement in ASD, from its connections to the social brain areas (which are the primary sites of ASD impairments) to the use of monogenic mouse models.
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Affiliation(s)
- Lisa Mapelli
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (T.S.); (E.D.)
- Correspondence: (L.M.); (F.P.)
| | - Teresa Soda
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (T.S.); (E.D.)
| | - Egidio D’Angelo
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (T.S.); (E.D.)
- Brain Connectivity Center, IRCCS Mondino Foundation, 27100 Pavia, Italy
| | - Francesca Prestori
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (T.S.); (E.D.)
- Correspondence: (L.M.); (F.P.)
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Collins BE, Neul JL. Rett Syndrome and MECP2 Duplication Syndrome: Disorders of MeCP2 Dosage. Neuropsychiatr Dis Treat 2022; 18:2813-2835. [PMID: 36471747 PMCID: PMC9719276 DOI: 10.2147/ndt.s371483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/14/2022] [Indexed: 11/30/2022] Open
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder caused predominantly by loss-of-function mutations in the gene Methyl-CpG-binding protein 2 (MECP2), which encodes the MeCP2 protein. RTT is a MECP2-related disorder, along with MECP2 duplication syndrome (MDS), caused by gain-of-function duplications of MECP2. Nearly two decades of research have advanced our knowledge of MeCP2 function in health and disease. The following review will discuss MeCP2 protein function and its dysregulation in the MECP2-related disorders RTT and MDS. This will include a discussion of the genetic underpinnings of these disorders, specifically how sporadic X-chromosome mutations arise and manifest in specific populations. We will then review current diagnostic guidelines and clinical manifestations of RTT and MDS. Next, we will delve into MeCP2 biology, describing the dual landscapes of methylated DNA and its reader MeCP2 across the neuronal genome as well as the function of MeCP2 as a transcriptional modulator. Following this, we will outline common MECP2 mutations and genotype-phenotype correlations in both diseases, with particular focus on mutations associated with relatively mild disease in RTT. We will also summarize decades of disease modeling and resulting molecular, synaptic, and behavioral phenotypes associated with RTT and MDS. Finally, we list several therapeutics in the development pipeline for RTT and MDS and available evidence of their safety and efficacy.
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Affiliation(s)
- Bridget E Collins
- Medical Scientist Training Program, Vanderbilt University, Nashville, TN, USA
| | - Jeffrey L Neul
- Vanderbilt Kennedy Center, Departments of Pediatrics, Pharmacology, and Special Education, Vanderbilt University Medical Center and Vanderbilt University, Nashville, TN, USA
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13
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Singh J, Lanzarini E, Nardocci N, Santosh P. Movement disorders in patients with Rett syndrome: A systematic review of evidence and associated clinical considerations. Psychiatry Clin Neurosci 2021; 75:369-393. [PMID: 34472659 PMCID: PMC9298304 DOI: 10.1111/pcn.13299] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/28/2021] [Accepted: 08/20/2021] [Indexed: 12/18/2022]
Abstract
AIM This systematic review identified and thematically appraised clinical evidence of movement disorders in patients with Rett syndrome (RTT). METHOD Using PRISMA criteria, six electronic databases were searched from inception to April 2021. A thematic analysis was then undertaken on the extracted data to identify potential themes. RESULTS Following the thematic analysis, six themes emerged: (i) clinical features of abnormal movement behaviors; (ii) mutational profile and its impact on movement disorders; (iii) symptoms and stressors that impact on movement disorders; (iv) possible underlying neurobiological mechanisms; (v) quality of life and movement disorders; and (vi) treatment of movement disorders. Current guidelines for managing movement disorders in general were then reviewed to provide possible treatment recommendations for RTT. CONCLUSION Our study offers an enriched data set for clinical investigations and treatment of fine and gross motor issues in RTT. A detailed understanding of genotype-phenotype relationships of movement disorders allows for more robust genetic counseling for families but can also assist healthcare professionals in terms of monitoring disease progression in RTT. The synthesis also showed that environmental enrichment would be beneficial for improving some aspects of movement disorders. The cerebellum, basal ganglia, alongside dysregulation of the cortico-basal ganglia-thalamo-cortical loop, are likely anatomical targets. A review of treatments for movement disorders also helped to provide recommendations for treating and managing movement disorders in patients with RTT.
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Affiliation(s)
- Jatinder Singh
- Department of Child and Adolescent Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,Centre for Interventional Paediatric Psychopharmacology and Rare Diseases, South London and Maudsley NHS Foundation Trust, London, UK.,Centre for Personalised Medicine in Rett Syndrome, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Evamaria Lanzarini
- Child and Adolescent Neuropsychiatry Unit, Infermi Hospital, Rimini, Italy
| | - Nardo Nardocci
- Department of Paediatric Neurology, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Paramala Santosh
- Department of Child and Adolescent Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,Centre for Interventional Paediatric Psychopharmacology and Rare Diseases, South London and Maudsley NHS Foundation Trust, London, UK.,Centre for Personalised Medicine in Rett Syndrome, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
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