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Sandoval SO, Méndez-Albelo NM, Xu Z, Zhao X. From wings to whiskers to stem cells: why every model matters in fragile X syndrome research. J Neurodev Disord 2024; 16:30. [PMID: 38872088 PMCID: PMC11177515 DOI: 10.1186/s11689-024-09545-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 05/21/2024] [Indexed: 06/15/2024] Open
Abstract
Fragile X syndrome (FXS) is caused by epigenetic silencing of the X-linked fragile X messenger ribonucleoprotein 1 (FMR1) gene located on chromosome Xq27.3, which leads to the loss of its protein product, fragile X messenger ribonucleoprotein (FMRP). It is the most prevalent inherited form of intellectual disability and the highest single genetic cause of autism. Since the discovery of the genetic basis of FXS, extensive studies using animal models and human pluripotent stem cells have unveiled the functions of FMRP and mechanisms underlying FXS. However, clinical trials have not yielded successful treatment. Here we review what we have learned from commonly used models for FXS, potential limitations of these models, and recommendations for future steps.
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Affiliation(s)
- Soraya O Sandoval
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Natasha M Méndez-Albelo
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA
- Molecular Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Zhiyan Xu
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA
- Graduate Program in Cell and Molecular Biology, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Xinyu Zhao
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA.
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA.
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2
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Rokach M, Portioli C, Brahmachari S, Estevão BM, Decuzzi P, Barak B. Tackling myelin deficits in neurodevelopmental disorders using drug delivery systems. Adv Drug Deliv Rev 2024; 207:115218. [PMID: 38403255 DOI: 10.1016/j.addr.2024.115218] [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: 11/14/2023] [Revised: 01/27/2024] [Accepted: 02/20/2024] [Indexed: 02/27/2024]
Abstract
Interest in myelin and its roles in almost all brain functions has been greatly increasing in recent years, leading to countless new studies on myelination, as a dominant process in the development of cognitive functions. Here, we explore the unique role myelin plays in the central nervous system and specifically discuss the results of altered myelination in neurodevelopmental disorders. We present parallel developmental trajectories involving myelination that correlate with the onset of cognitive impairment in neurodevelopmental disorders and discuss the key challenges in the treatment of these chronic disorders. Recent developments in drug repurposing and nano/micro particle-based therapies are reviewed as a possible pathway to circumvent some of the main hurdles associated with early intervention, including patient's adherence and compliance, side effects, relapse, and faster route to possible treatment of these disorders. The strategy of drug encapsulation overcomes drug solubility and metabolism, with the possibility of drug targeting to a specific compartment, reducing side effects upon systemic administration.
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Affiliation(s)
- May Rokach
- Sagol School of Neuroscience, Tel-Aviv University, Israel
| | - Corinne Portioli
- Laboratory of Nanotechnology for Precision Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Sayanti Brahmachari
- Laboratory of Nanotechnology for Precision Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Bianca Martins Estevão
- Laboratory of Nanotechnology for Precision Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Paolo Decuzzi
- Laboratory of Nanotechnology for Precision Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Boaz Barak
- Sagol School of Neuroscience, Tel-Aviv University, Israel; Faculty of Social Sciences, The School of Psychological Sciences, Tel-Aviv University, Israel.
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Meneghetti N, Vannini E, Mazzoni A. Rodents' visual gamma as a biomarker of pathological neural conditions. J Physiol 2024; 602:1017-1048. [PMID: 38372352 DOI: 10.1113/jp283858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 01/23/2024] [Indexed: 02/20/2024] Open
Abstract
Neural gamma oscillations (indicatively 30-100 Hz) are ubiquitous: they are associated with a broad range of functions in multiple cortical areas and across many animal species. Experimental and computational works established gamma rhythms as a global emergent property of neuronal networks generated by the balanced and coordinated interaction of excitation and inhibition. Coherently, gamma activity is strongly influenced by the alterations of synaptic dynamics which are often associated with pathological neural dysfunctions. We argue therefore that these oscillations are an optimal biomarker for probing the mechanism of cortical dysfunctions. Gamma oscillations are also highly sensitive to external stimuli in sensory cortices, especially the primary visual cortex (V1), where the stimulus dependence of gamma oscillations has been thoroughly investigated. Gamma manipulation by visual stimuli tuning is particularly easy in rodents, which have become a standard animal model for investigating the effects of network alterations on gamma oscillations. Overall, gamma in the rodents' visual cortex offers an accessible probe on dysfunctional information processing in pathological conditions. Beyond vision-related dysfunctions, alterations of gamma oscillations in rodents were indeed also reported in neural deficits such as migraine, epilepsy and neurodegenerative or neuropsychiatric conditions such as Alzheimer's, schizophrenia and autism spectrum disorders. Altogether, the connections between visual cortical gamma activity and physio-pathological conditions in rodent models underscore the potential of gamma oscillations as markers of neuronal (dys)functioning.
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Affiliation(s)
- Nicolò Meneghetti
- The Biorobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
- Department of Excellence for Robotics and AI, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Eleonora Vannini
- Neuroscience Institute, National Research Council (CNR), Pisa, Italy
| | - Alberto Mazzoni
- The Biorobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
- Department of Excellence for Robotics and AI, Scuola Superiore Sant'Anna, Pisa, Italy
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4
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Neul JL. Challenges in developing therapies in fragile X syndrome: how the FXLEARN trial can guide research. J Clin Invest 2024; 134:e175036. [PMID: 38426491 PMCID: PMC10904042 DOI: 10.1172/jci175036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024] Open
Abstract
Fragile X syndrome (FXS), the most common inherited cause of intellectual disability and the single-gene cause of autism, is caused by decreased expression of the fragile X messenger ribonucleoprotein protein (FMRP), a ribosomal-associated RNA-binding protein involved in translational repression. Extensive preclinical work in several FXS animal models supported the therapeutic potential of decreasing metabotropic glutamate receptor (mGluR) signaling to correct translation of proteins related to synaptic plasticity; however, multiple clinical trials failed to show conclusive evidence of efficacy. In this issue of the JCI, Berry-Kravis and colleagues conducted the FXLEARN clinical trial to address experimental design concerns from previous trials. Unfortunately, despite treatment of young children with combined pharmacological and learning interventions for a prolonged period, no efficacy of blocking mGluR activity was observed. Future systematic evaluation of potential therapeutic approaches should evaluate consistency between human and animal pathophysiological mechanisms, utilize innovative clinical trial design from FXLEARN, and incorporate translatable biomarkers.
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Orm S, Wood J, Corbett B, Fjermestad K. Suicidal Risk Behaviors in Adolescents With Rare Neurodevelopmental Disorders: The Role of Sex, Autistic Traits, and Mental Health Difficulties. J Pediatr Psychol 2023; 48:852-860. [PMID: 37553221 PMCID: PMC10857814 DOI: 10.1093/jpepsy/jsad051] [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: 01/18/2023] [Revised: 07/24/2023] [Accepted: 07/26/2023] [Indexed: 08/10/2023] Open
Abstract
OBJECTIVE Autistic traits are associated with mental health difficulties and risk of suicidal risk behaviors among adolescents. Little is known about how autistic traits affect the mental health of adolescents with rare neurodevelopmental disorders (RNDs). The aim of this study was to investigate the relationship between autistic traits, mental health difficulties, and suicidal risk behaviors in adolescents with RNDs. METHODS Parents (N = 93) completed the Child Behavior Checklist, Social Communication Questionnaire, and Social Responsiveness Scale about their adolescent (Mage = 13.1, SD = 2.3, 62.4% females) with an RND (e.g., sex chromosome aneuploidies, Fragile X syndrome, 22q11.2 deletion syndrome). The data were analyzed with hierarchical logistic regression analysis. RESULTS The prevalence of suicidal risk behaviors (16.1%) was similar to that reported among autistic youth and was higher among boys than girls. More autistic traits were associated with suicidal risk behaviors in bivariate analysis. In multivariate analysis, more anxiety/depressive symptoms were associated with more suicidal risk behaviors and externalizing problems associated with suicidal risk behaviors beyond autistic traits and anxiety/depressive symptoms. CONCLUSION Adolescents with RNDs are at risk of suicidal risk behaviors, especially those with higher levels of autistic traits, anxiety/depressive symptoms, and externalizing problems. Assessment of autistic traits, mental health difficulties, and suicide risk may be indicated for adolescents with RNDs to determine if corresponding intervention is needed.
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Affiliation(s)
- Stian Orm
- Division of Mental Health Care, Innlandet Hospital Trust, Norway
- Frambu Resource Center for Rare Disorders, Norway
| | - Jeffrey Wood
- Department of Education, University of California, USA
| | - Blythe Corbett
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, USA
| | - Krister Fjermestad
- Frambu Resource Center for Rare Disorders, Norway
- Department of Psychology, University of Oslo, Norway
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Lachiewicz AM, Stackhouse TM, Burgess K, Burgess D, Andrews HF, Choo TH, Kaufmann WE, Kidd SA. Sensory Symptoms and Signs of Hyperarousal in Individuals with Fragile X Syndrome: Findings from the FORWARD Registry and Database Multisite Study. J Autism Dev Disord 2023:10.1007/s10803-023-06135-y. [PMID: 37840096 DOI: 10.1007/s10803-023-06135-y] [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] [Accepted: 09/06/2023] [Indexed: 10/17/2023]
Abstract
This study was designed to increase our understanding about characteristics and the impact of sensory symptoms (SS) and signs of hyperarousal (HA) in individuals with fragile X syndrome (FXS) from childhood through early adulthood and by gender. Data derived from the Fragile X Online Registry With Accessible Research Database (FORWARD), a natural history study of FXS, were analyzed using descriptive statistics and multivariate linear and logistic regression models to examine SS and signs of HA, their impact on behavioral regulation and limitations on the subject/family. The sample (N = 933) consisted of 720 males and 213 females. More males were affected with SS (87% vs. 68%) and signs of HA (92% vs. 79%). Subjects who were endorsed as having a strong sensory response had more comorbidities, including behavioral problems. The predominant SS was difficulty with eye gaze that increased with age in both genders. As individuals age, there was less use of non-medication therapies, such as occupational therapy (OT)/physical therapy (PT), but there was more use of psychopharmacological medications and investigational drugs for behaviors. Multiple regression models suggested that endorsing SS and signs of HA was associated with statistically significantly increased ABC-C-I subscale scores and limited participation in everyday activities. This study improves our understanding of SS and signs of HA as well as their impact in FXS. It supports the need for more research regarding these clinical symptoms, especially to understand how they contribute to well-known behavioral concerns.
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Affiliation(s)
- Ave M Lachiewicz
- Department of Pediatrics, Duke University Health System, Durham, NC, USA.
| | | | | | - Debra Burgess
- Department of Pediatrics, Duke University Health System, Durham, NC, USA
| | - Howard F Andrews
- Departments of Psychiatry and Biostatistics, Mailman School of Public Health, Columbia University, Irving Medical Center, New York, NY, USA
| | - Tse-Hwei Choo
- Division of Mental Health Data Science, New York State Psychiatric Institute, New York, NY, USA
| | - Walter E Kaufmann
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
| | - Sharon A Kidd
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA
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7
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Berry-Kravis E, Abbeduto L, Hagerman R, Coffey CS, Cudkowicz M, Erickson CA, McDuffie A, Hessl D, Ethridge L, Tassone F, Kaufmann WE, Friedmann K, Bullard L, Hoffmann A, Veenstra-VanderWeele J, Staley K, Klements D, Moshinsky M, Harkey B, Long J, Fedler J, Klingner E, Ecklund D, Costigan M, Huff T, Pearson B. Effects of AFQ056 on language learning in fragile X syndrome. J Clin Invest 2023; 134:e171723. [PMID: 37651202 PMCID: PMC10904045 DOI: 10.1172/jci171723] [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: 04/24/2023] [Accepted: 08/22/2023] [Indexed: 09/02/2023] Open
Abstract
BACKGROUNDFXLEARN, the first-ever large multisite trial of effects of disease-targeted pharmacotherapy on learning, was designed to explore a paradigm for measuring effects of mechanism-targeted treatment in fragile X syndrome (FXS). In FXLEARN, the effects of metabotropic glutamate receptor type 5 (mGluR5) negative allosteric modulator (NAM) AFQ056 on language learning were evaluated in 3- to 6-year-old children with FXS, expected to have more learning plasticity than adults, for whom prior trials of mGluR5 NAMs have failed.METHODSAfter a 4-month single-blind placebo lead-in, participants were randomized 1:1 to AFQ056 or placebo, with 2 months of dose optimization to the maximum tolerated dose, then 6 months of treatment during which a language-learning intervention was implemented for both groups. The primary outcome was a centrally scored videotaped communication measure, the Weighted Communication Scale (WCS). Secondary outcomes were objective performance-based and parent-reported cognitive and language measures.RESULTSFXLEARN enrolled 110 participants, randomized 99, and had 91 who completed the placebo-controlled period. Although both groups made language progress and there were no safety issues, the change in WCS score during the placebo-controlled period was not significantly different between the AFQ056 and placebo-treated groups, nor were there any significant between-group differences in change in any secondary measures.CONCLUSIONDespite the large body of evidence supporting use of mGluR5 NAMs in animal models of FXS, this study suggests that this mechanism of action does not translate into benefit for the human FXS population and that better strategies are needed to determine which mechanisms will translate from preclinical models to humans in genetic neurodevelopmental disorders.TRIAL REGISTRATIONClincalTrials.gov NCT02920892.FUNDING SOURCESNeuroNEXT network NIH grants U01NS096767, U24NS107200, U24NS107209, U01NS077323, U24NS107183, U24NS107168, U24NS107128, U24NS107199, U24NS107198, U24NS107166, U10NS077368, U01NS077366, U24NS107205, U01NS077179, and U01NS077352; NIH grant P50HD103526; and Novartis IIT grant AFQ056X2201T for provision of AFQ056.
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Affiliation(s)
- Elizabeth Berry-Kravis
- Departments of Pediatrics, Neurological Sciences, and Anatomy & Cell Biology, Rush University Medical Center, Chicago, Illinois, USA
| | - Leonard Abbeduto
- MIND Institute and Department of Psychiatry and Behavioral Sciences and
| | - Randi Hagerman
- MIND Institute and Department of Pediatrics, UCD, Sacramento, California, USA
| | | | - Merit Cudkowicz
- Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Craig A. Erickson
- Division of Child and Adolescent Psychiatry, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
| | - Andrea McDuffie
- MIND Institute and Department of Psychiatry and Behavioral Sciences and
| | - David Hessl
- MIND Institute and Department of Psychiatry and Behavioral Sciences and
| | - Lauren Ethridge
- Department of Psychology, University of Oklahoma, Norman, Oklahoma, and Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Flora Tassone
- MIND Institute and Department of Biochemistry and Molecular Medicine, UCD, Sacramento, California, USA
| | - Walter E. Kaufmann
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | | | - Lauren Bullard
- MIND Institute and Department of Psychiatry and Behavioral Sciences and
| | - Anne Hoffmann
- Departments of Pediatrics and Communication Disorders and Sciences, Rush University Medical Center, Chicago, Illinois, USA
| | - Jeremy Veenstra-VanderWeele
- Department of Psychiatry, Columbia University, and New York State Psychiatric Institute, New York, New York, USA
| | - Kevin Staley
- Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - David Klements
- Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Michael Moshinsky
- Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Brittney Harkey
- Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Jeff Long
- Department of Biostatistics, University of Iowa, Iowa City, Iowa, USA
| | - Janel Fedler
- Department of Biostatistics, University of Iowa, Iowa City, Iowa, USA
| | | | - Dixie Ecklund
- Department of Biostatistics, University of Iowa, Iowa City, Iowa, USA
| | - Michele Costigan
- Department of Biostatistics, University of Iowa, Iowa City, Iowa, USA
| | - Trevis Huff
- Department of Biostatistics, University of Iowa, Iowa City, Iowa, USA
| | - Brenda Pearson
- Department of Biostatistics, University of Iowa, Iowa City, Iowa, USA
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Aishworiya R, Chi MH, Zafarullah M, Mendoza G, Ponzini MD, Kim K, Biag HMB, Thurman AJ, Abbeduto L, Hessl D, Randol JL, Bolduc FV, Jacquemont S, Lippé S, Hagerman P, Hagerman R, Schneider A, Tassone F. Intercorrelation of Molecular Biomarkers and Clinical Phenotype Measures in Fragile X Syndrome. Cells 2023; 12:1920. [PMID: 37508583 PMCID: PMC10377864 DOI: 10.3390/cells12141920] [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: 05/18/2023] [Revised: 07/05/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
This study contributes to a greater understanding of the utility of molecular biomarkers to identify clinical phenotypes of fragile X syndrome (FXS). Correlations of baseline clinical trial data (molecular measures-FMR1 mRNA, CYFIP1 mRNA, MMP9 and FMRP protein expression levels, nonverbal IQ, body mass index and weight, language level, NIH Toolbox, adaptive behavior rating, autism, and other mental health correlates) of 59 participants with FXS ages of 6-32 years are reported. FMR1 mRNA expression levels correlated positively with adaptive functioning levels, expressive language, and specific NIH Toolbox measures. The findings of a positive correlation of MMP-9 levels with obesity, CYFIP1 mRNA with mood and autistic symptoms, and FMR1 mRNA expression level with better cognitive, language, and adaptive functions indicate potential biomarkers for specific FXS phenotypes. These may be potential markers for future clinical trials for targeted treatments of FXS.
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Affiliation(s)
- Ramkumar Aishworiya
- MIND Institute, University of California Davis Medical Center, Sacramento, CA 95817, USA; (R.A.); (M.D.P.); (H.M.B.B.)
- Khoo Teck Puat-National University Children’s Medical Institute, National University Health System, Singapore 119074, Singapore
- Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore
| | - Mei-Hung Chi
- MIND Institute, University of California Davis Medical Center, Sacramento, CA 95817, USA; (R.A.); (M.D.P.); (H.M.B.B.)
- Department of Psychiatry, National Cheng Kung University Hospital, Tainan 704, Taiwan
| | - Marwa Zafarullah
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA 95817, USA (G.M.)
| | - Guadalupe Mendoza
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA 95817, USA (G.M.)
| | - Matthew Dominic Ponzini
- MIND Institute, University of California Davis Medical Center, Sacramento, CA 95817, USA; (R.A.); (M.D.P.); (H.M.B.B.)
- Department of Public Health Sciences, School of Medicine, University of California Davis, Sacramento, CA 95817, USA
| | - Kyoungmi Kim
- MIND Institute, University of California Davis Medical Center, Sacramento, CA 95817, USA; (R.A.); (M.D.P.); (H.M.B.B.)
- Department of Public Health Sciences, School of Medicine, University of California Davis, Sacramento, CA 95817, USA
| | - Hazel Maridith Barlahan Biag
- MIND Institute, University of California Davis Medical Center, Sacramento, CA 95817, USA; (R.A.); (M.D.P.); (H.M.B.B.)
- Department of Pediatrics, School of Medicine, University of California Davis, Sacramento, CA 95817, USA
| | - Angela John Thurman
- MIND Institute, University of California Davis Medical Center, Sacramento, CA 95817, USA; (R.A.); (M.D.P.); (H.M.B.B.)
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California Davis, Sacramento, CA 95817, USA
| | - Leonard Abbeduto
- MIND Institute, University of California Davis Medical Center, Sacramento, CA 95817, USA; (R.A.); (M.D.P.); (H.M.B.B.)
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California Davis, Sacramento, CA 95817, USA
| | - David Hessl
- MIND Institute, University of California Davis Medical Center, Sacramento, CA 95817, USA; (R.A.); (M.D.P.); (H.M.B.B.)
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California Davis, Sacramento, CA 95817, USA
| | - Jamie Leah Randol
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA 95817, USA (G.M.)
- Integrative Genetics and Genomics Graduate Group, University of California Davis, One Shields Avenue, Davis, CA 95616, USA
- UC Davis Biotechnology Program, University of California Davis, Davis, CA 95616, USA
| | - Francois V. Bolduc
- Department of Pediatrics, Department of Medical Genetics, Women and Children Health Research Institute, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Sebastien Jacquemont
- CHU Sainte-Justine Research Center, Université de Montréal, Montreal, QC H3T 1J4, Canada
- Department of Pediatrics, University of Montreal, Montreal, QC H3T 1J4, Canada
| | - Sarah Lippé
- CHU Sainte-Justine Research Center, Université de Montréal, Montreal, QC H3T 1J4, Canada
- Department of Psychology, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Paul Hagerman
- MIND Institute, University of California Davis Medical Center, Sacramento, CA 95817, USA; (R.A.); (M.D.P.); (H.M.B.B.)
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA 95817, USA (G.M.)
| | - Randi Hagerman
- MIND Institute, University of California Davis Medical Center, Sacramento, CA 95817, USA; (R.A.); (M.D.P.); (H.M.B.B.)
- Department of Pediatrics, School of Medicine, University of California Davis, Sacramento, CA 95817, USA
| | - Andrea Schneider
- MIND Institute, University of California Davis Medical Center, Sacramento, CA 95817, USA; (R.A.); (M.D.P.); (H.M.B.B.)
- Department of Pediatrics, School of Medicine, University of California Davis, Sacramento, CA 95817, USA
| | - Flora Tassone
- MIND Institute, University of California Davis Medical Center, Sacramento, CA 95817, USA; (R.A.); (M.D.P.); (H.M.B.B.)
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA 95817, USA (G.M.)
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Elhawary NA, AlJahdali IA, Abumansour IS, Azher ZA, Falemban AH, Madani WM, Alosaimi W, Alghamdi G, Sindi IA. Phenotypic variability to medication management: an update on fragile X syndrome. Hum Genomics 2023; 17:60. [PMID: 37420260 DOI: 10.1186/s40246-023-00507-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 07/03/2023] [Indexed: 07/09/2023] Open
Abstract
This review discusses the discovery, epidemiology, pathophysiology, genetic etiology, molecular diagnosis, and medication-based management of fragile X syndrome (FXS). It also highlights the syndrome's variable expressivity and common comorbid and overlapping conditions. FXS is an X-linked dominant disorder associated with a wide spectrum of clinical features, including but not limited to intellectual disability, autism spectrum disorder, language deficits, macroorchidism, seizures, and anxiety. Its prevalence in the general population is approximately 1 in 5000-7000 men and 1 in 4000-6000 women worldwide. FXS is associated with the fragile X messenger ribonucleoprotein 1 (FMR1) gene located at locus Xq27.3 and encodes the fragile X messenger ribonucleoprotein (FMRP). Most individuals with FXS have an FMR1 allele with > 200 CGG repeats (full mutation) and hypermethylation of the CpG island proximal to the repeats, which silences the gene's promoter. Some individuals have mosaicism in the size of the CGG repeats or in hypermethylation of the CpG island, both produce some FMRP and give rise to milder cognitive and behavioral deficits than in non-mosaic individuals with FXS. As in several monogenic disorders, modifier genes influence the penetrance of FMR1 mutations and FXS's variable expressivity by regulating the pathophysiological mechanisms related to the syndrome's behavioral features. Although there is no cure for FXS, prenatal molecular diagnostic testing is recommended to facilitate early diagnosis. Pharmacologic agents can reduce some behavioral features of FXS, and researchers are investigating whether gene editing can be used to demethylate the FMR1 promoter region to improve patient outcomes. Moreover, clustered regularly interspaced palindromic repeats (CRISPR)/Cas9 and developed nuclease defective Cas9 (dCas9) strategies have promised options of genome editing in gain-of-function mutations to rewrite new genetic information into a specified DNA site, are also being studied.
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Affiliation(s)
- Nasser A Elhawary
- Department of Medical Genetics, College of Medicine, Umm Al-Qura University, Mecca, 21955, Saudi Arabia.
| | - Imad A AlJahdali
- Department of Community Medicine, College of Medicine, Umm Al-Qura University, Mecca, Saudi Arabia
| | - Iman S Abumansour
- Department of Medical Genetics, College of Medicine, Umm Al-Qura University, Mecca, 21955, Saudi Arabia
| | - Zohor A Azher
- Department of Medical Genetics, College of Medicine, Umm Al-Qura University, Mecca, 21955, Saudi Arabia
| | - Alaa H Falemban
- Department of Pharmacology and Toxicology, College of Medicine, Umm Al-Qura University, Mecca, 24382, Saudi Arabia
| | - Wefaq M Madani
- Department of Hematology and Immunology, Faculty of Medicine, Umm Al-Qura University, Mecca, Saudi Arabia
| | - Wafaa Alosaimi
- Department of Hematology, Maternity and Children Hospital, Mecca, Saudi Arabia
| | - Ghydda Alghamdi
- Department of Medical Genetics, College of Medicine, Umm Al-Qura University, Mecca, 21955, Saudi Arabia
| | - Ikhlas A Sindi
- Department of Biology, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
- Preparatory Year Program, Batterjee Medical College, Jeddah, 21442, Saudi Arabia
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10
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Acero-Garcés DO, Saldarriaga W, Cabal-Herrera AM, Rojas CA, Hagerman RJ. Fragile X Syndrome in children. Colomb Med (Cali) 2023; 54:e4005089. [PMID: 37664646 PMCID: PMC10469670 DOI: 10.25100/cm.v54i2.5089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 11/28/2022] [Accepted: 05/14/2023] [Indexed: 09/05/2023] Open
Abstract
Fragile X syndrome is caused by the expansion of CGG triplets in the FMR1 gene, which generates epigenetic changes that silence its expression. The absence of the protein coded by this gene, FMRP, causes cellular dysfunction, leading to impaired brain development and functional abnormalities. The physical and neurologic manifestations of the disease appear early in life and may suggest the diagnosis. However, it must be confirmed by molecular tests. It affects multiple areas of daily living and greatly burdens the affected individuals and their families. Fragile X syndrome is the most common monogenic cause of intellectual disability and autism spectrum disorder; the diagnosis should be suspected in every patient with neurodevelopmental delay. Early interventions could improve the functional prognosis of patients with Fragile X syndrome, significantly impacting their quality of life and daily functioning. Therefore, healthcare for children with Fragile X syndrome should include a multidisciplinary approach.
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Affiliation(s)
| | - Wilmar Saldarriaga
- Universidad del Valle, Facultad de Salud, Escuela de Medicina, Cali, Colombia
- Universidad del Valle, Facultad de Salud, Escuela de Ciencias Básicas, Cali, Colombia
| | | | - Christian A. Rojas
- Universidad del Valle, Facultad de Salud, Escuela de Medicina, Cali, Colombia
| | - Randi J. Hagerman
- University of California, Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, Sacramento, CA, USA
- Davis Medical Center, Sacramento, CA, USA
- University of California, Department of Pediatrics, Davis, CA, USA
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11
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Berry-Kravis E. Disease-Targeted Treatment Translation in Fragile X Syndrome as a Model for Neurodevelopmental Disorders. J Child Neurol 2022; 37:797-812. [PMID: 35791522 DOI: 10.1177/08830738221089740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Fragile X syndrome (FXS), the most common monogenic cause of intellectual disability and autism spectrum disorder, has been one of the first neurodevelopmental disorders in which molecular and neuronal mechanisms of disease were identified, leading to the concept of targeting the underlying disease to reverse symptoms. Translating findings in basic science and animal models to humans with FXS has proven difficult. These challenges have prompted the FXS field to organize to build interlocking projects and initiatives to improve consistency of supportive care, make clinical research accessible to families, generate collaborative research on natural history, outcome measures and biomarkers, and create clinical trial consortia and novel trial designs. This work has resulted in improved success in recent clinical trials, providing key steps toward regulatory approval of disease-targeted treatments for FXS. Progress in the FXS field has informed translation of transformative new disease-targeted therapies for other monogenic neurodevelopmental disorders.
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Affiliation(s)
- Elizabeth Berry-Kravis
- Departments of Pediatrics, Neurological Sciences, Anatomy and Cell Biology, Rush University Medical Center, Chicago, IL, USA
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12
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Jeon SJ, Kwon H, Bae HJ, Gonzales EL, Kim J, Chung HJ, Kim DH, Ryu JH, Shin CY. Agmatine relieves behavioral impairments in Fragile X mice model. Neuropharmacology 2022; 219:109234. [PMID: 36057317 DOI: 10.1016/j.neuropharm.2022.109234] [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: 03/30/2022] [Revised: 07/25/2022] [Accepted: 08/21/2022] [Indexed: 10/31/2022]
Abstract
BACKGROUND Fragile X syndrome (FXS) is the most common heritable form of neurodevelopmental disorder, which is caused by the loss of fragile X mental retardation protein (FMRP) expression. Despite the unceasing efforts to develop therapeutic agents against FXS based on the pathophysiological changes observed in animal models of FXS and human patients, therapeutic candidates including mGluR signaling modulators have failed to provide sufficient effects. Based on the recent successful demonstration of an endogenous polyamine, agmatine, to improve the autism-like symptoms in the valproic acid animal model of autism, we investigated the effects of agmatine against FXS symptoms using Fmr1 knockout (KO) mice. METHODS We used male Fmr1 KO mice for behavioral tests such as marble burying, open-field test, memory tasks, social interaction tests and startle response to confirm the symptoms of FXS. We also checked the electrophysiological profile of neural activity in agmatine-treated Fmr1 KO mice. RESULTS Agmatine reversed the compulsion, learning and memory deficits, hyperactivity, aberrant social interaction, and communication deficit in Fmr1 KO mice while it normalized the aberrant LTP and LTD in the hippocampus. CONCLUSIONS The results highlight the potential of agmatine's novel disease-ameliorating effects in FXS, which warrants further studies to ascertain whether these findings translate into clinical effects in FXS patients.
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Affiliation(s)
- Se Jin Jeon
- Department of Pharmacology and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, Seoul, 05029, Republic of Korea; Department of Integrative Biotechnology, College of Science and Technology, Sahmyook University, Seoul, 01795, Republic of Korea
| | - Huiyoung Kwon
- Department of Pharmacology and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, Seoul, 05029, Republic of Korea
| | - Ho Jung Bae
- Department of Life and Nanopharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul, 02447, Republic of Korea
| | - Edson Luck Gonzales
- Department of Pharmacology and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, Seoul, 05029, Republic of Korea
| | - Junhyeong Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Hye Jin Chung
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Dong Hyun Kim
- Department of Pharmacology and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, Seoul, 05029, Republic of Korea
| | - Jong Hoon Ryu
- Department of Life and Nanopharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul, 02447, Republic of Korea
| | - Chan Young Shin
- Department of Pharmacology and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, Seoul, 05029, Republic of Korea.
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13
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Lipid-Based Molecules on Signaling Pathways in Autism Spectrum Disorder. Int J Mol Sci 2022; 23:ijms23179803. [PMID: 36077195 PMCID: PMC9456412 DOI: 10.3390/ijms23179803] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/22/2022] [Accepted: 08/23/2022] [Indexed: 11/16/2022] Open
Abstract
The signaling pathways associated with lipid metabolism contribute to the pathophysiology of autism spectrum disorder (ASD) and provide insights for devising new therapeutic strategies. Prostaglandin E2 is a membrane-derived lipid molecule that contributes to developing ASD associated with canonical Wnt signaling. Cyclooxygenase-2 plays a key role in neuroinflammation and is implicated in the pathogenesis of neurodevelopmental diseases, such as ASD. The endocannabinoid system maintains a balance between inflammatory and redox status and synaptic plasticity and is a potential target for ASD pathophysiology. Redox signaling refers to specific and usually reversible oxidation–reduction reactions, some of which are also involved in pathways accounting for the abnormal behavior observed in ASD. Redox signaling and redox status-sensitive transcription factors contribute to the pathophysiology of ASD. Cannabinoids regulate the redox balance by altering the levels and activity of antioxidant molecules via ROS-producing NADPH oxidase (NOX) and ROS-scavenging superoxide dismutase enzymes. These signaling cascades integrate a broad range of neurodevelopmental processes that may be involved in the pathophysiology of ASD. Based on these pathways, we highlight putative targets that may be used for devising novel therapeutic interventions for ASD.
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14
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Berry-Kravis E. Fragile X Syndrome: Supportive Treatment, Unmet Needs, and Paths to Novel Interventions and Disease-Targeted Therapies. AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2022; 127:90-94. [PMID: 35180774 DOI: 10.1352/1944-7558-127.2.90] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Indexed: 06/14/2023]
Abstract
Fragile X syndrome (FXS), as a monogenic cause of intellectual disability and autism spectrum disorder, has been one of the first neurodevelopmental disorders in which molecular and neuronal mechanisms of disease have been identified, leading to the concept of targeting the underlying disease to reverse symptoms. Translating findings in basic science and animal models to humans with FXS has proven difficult. These challenges have prompted the FXS field to organize to build interlocking projects to support initiatives to improve supportive care, make clinical research accessible to families, generate collaborative research on natural history and outcome measures, and create clinical trial consortia and novel trial designs.
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15
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Protic DD, Aishworiya R, Salcedo-Arellano MJ, Tang SJ, Milisavljevic J, Mitrovic F, Hagerman RJ, Budimirovic DB. Fragile X Syndrome: From Molecular Aspect to Clinical Treatment. Int J Mol Sci 2022; 23:ijms23041935. [PMID: 35216055 PMCID: PMC8875233 DOI: 10.3390/ijms23041935] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/01/2022] [Accepted: 02/02/2022] [Indexed: 02/01/2023] Open
Abstract
Fragile X syndrome (FXS) is a neurodevelopmental disorder caused by the full mutation as well as highly localized methylation of the fragile X mental retardation 1 (FMR1) gene on the long arm of the X chromosome. Children with FXS are commonly co-diagnosed with Autism Spectrum Disorder, attention and learning problems, anxiety, aggressive behavior and sleep disorder, and early interventions have improved many behavior symptoms associated with FXS. In this review, we performed a literature search of original and review articles data of clinical trials and book chapters using MEDLINE (1990-2021) and ClinicalTrials.gov. While we have reviewed the biological importance of the fragile X mental retardation protein (FMRP), the FXS phenotype, and current diagnosis techniques, the emphasis of this review is on clinical interventions. Early non-pharmacological interventions in combination with pharmacotherapy and targeted treatments aiming to reverse dysregulated brain pathways are the mainstream of treatment in FXS. Overall, early diagnosis and interventions are fundamental to achieve optimal clinical outcomes in FXS.
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Affiliation(s)
- Dragana D. Protic
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11129 Belgrade, Serbia
- Correspondence: (D.D.P.); (D.B.B.); Tel.: +381-11-36-43-389 (D.D.P.); +1-443-923-2634 (D.B.B.)
| | - Ramkumar Aishworiya
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute UCDH, University of California Davis, 2825 50th Street, Sacramento, CA 95817, USA; (R.A.); (M.J.S.-A.); (S.J.T.); (R.J.H.)
- Khoo Teck Puat-National University Children’s Medical Institute, National University Health System, 5 Lower Kent Ridge Road, Singapore 119074, Singapore
| | - Maria Jimena Salcedo-Arellano
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute UCDH, University of California Davis, 2825 50th Street, Sacramento, CA 95817, USA; (R.A.); (M.J.S.-A.); (S.J.T.); (R.J.H.)
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA 95817, USA
- Department of Pathology and Laboratory Medicine, University of California Davis School of Medicine, Sacramento, CA 95817, USA
| | - Si Jie Tang
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute UCDH, University of California Davis, 2825 50th Street, Sacramento, CA 95817, USA; (R.A.); (M.J.S.-A.); (S.J.T.); (R.J.H.)
| | - Jelena Milisavljevic
- Faculty of Medicine, University of Belgrade, 11129 Belgrade, Serbia; (J.M.); (F.M.)
| | - Filip Mitrovic
- Faculty of Medicine, University of Belgrade, 11129 Belgrade, Serbia; (J.M.); (F.M.)
| | - Randi J. Hagerman
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute UCDH, University of California Davis, 2825 50th Street, Sacramento, CA 95817, USA; (R.A.); (M.J.S.-A.); (S.J.T.); (R.J.H.)
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA 95817, USA
| | - Dejan B. Budimirovic
- Department of Psychiatry, Fragile X Clinic, Kennedy Krieger Institute, Baltimore, MD 21205, USA
- Department of Psychiatry & Behavioral Sciences-Child Psychiatry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Correspondence: (D.D.P.); (D.B.B.); Tel.: +381-11-36-43-389 (D.D.P.); +1-443-923-2634 (D.B.B.)
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16
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Turbitt E, Newson AJ, Biesecker BB, Wilfond BS. Enrolling Children in Clinical Trials for Genetic Neurodevelopmental Conditions: Ethics, Parental Decisions, and Children's Identities. Ethics Hum Res 2021; 43:27-36. [PMID: 34196500 DOI: 10.1002/eahr.500097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Knowledge of genetic mechanisms contributing to neurodevelopmental conditions is advancing. This is informing development of new drugs to treat or ameliorate these conditions, through targeting underlying genetic pathways. Drugs are tested in clinical trials, necessitating parents to engage with decisions about whether to enroll their child. In this article, we consider important ethical issues to anticipate as clinical research opportunities in genetic neurodevelopmental conditions arise. For example, genetic pathways targeted by the drugs may interact with valued character and personality traits. It is essential that recruitment and consent processes are optimized for families who will grapple with whether these novel drug treatments interact with their child's personality and authentic identity. We call for focused social science research and further normative analysis so that parents are better supported to make informed choices. Additionally, clinical research regulators should have a sound understanding of the contextual experiences regarding how this population of parents engages with decisions.
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Affiliation(s)
- Erin Turbitt
- Lecturer in the Graduate School of Health at the University of Technology Sydney
| | - Ainsley J Newson
- Professor of bioethics at Sydney Health Ethics in the Faculty of Medicine and Health at the University of Sydney
| | | | - Benjamin S Wilfond
- Professor of pediatrics at the University of Washington and Seattle Children's Research Institute
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17
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Ozlu C, Bailey RM, Sinnett S, Goodspeed KD. Gene Transfer Therapy for Neurodevelopmental Disorders. Dev Neurosci 2021; 43:230-240. [PMID: 33882495 DOI: 10.1159/000515434] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/13/2021] [Indexed: 11/19/2022] Open
Abstract
Neurodevelopmental disorders (NDDs) include a broad spectrum of disorders that disrupt normal brain development. Though some NDDs are caused by acquired insults (i.e., toxic or infectious encephalopathy) or may be cryptogenic, many NDDs are caused by variants in a single gene or groups of genes that disrupt neuronal development or function. In this review, we will focus on those NDDs with a genetic etiology. The exact mechanism, timing, and progression of the molecular pathology are seldom well known; however, the abnormalities in development typically manifest in similar patterns such as delays or regression in motor function, social skills, and language or cognitive abilities. Severity of impairment can vary widely. At present, only symptomatic treatments are available to manage seizures and behavioral problems commonly seen in NDDs. In recent years, there has been a rapid expansion of research into gene therapy using adeno-associated viruses (AAVs). Using AAVs as vectors to replace the non- or dysfunctional gene in vivo is a relatively simple model which has created an unprecedented opportunity for the future of NDD treatment. Advances in this field are of paramount importance as NDDs lead to a massive lifelong burden of disease on the affected individuals and families. In this article, we review the unique advantages and challenges of AAV gene therapies. We then look at potential applications of gene therapy for 3 of the more common NDDs (Rett syndrome, fragile X syndrome, and Angelman syndrome), as well as 2 less common NDDs (SLC13A5 deficiency disorder and SLC6A1-related disorder). We will review the available natural history of each disease and current state of preclinical studies including a discussion on the application of AAV gene therapies for each disease.
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Affiliation(s)
- Can Ozlu
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Rachel M Bailey
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Center for Alzheimer's and Neurodegenerative Diseases, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Sarah Sinnett
- Department of Pediatrics, 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
| | - Kimberly D Goodspeed
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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18
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Cell-type-specific profiling of human cellular models of fragile X syndrome reveal PI3K-dependent defects in translation and neurogenesis. Cell Rep 2021; 35:108991. [PMID: 33852833 PMCID: PMC8133829 DOI: 10.1016/j.celrep.2021.108991] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/08/2021] [Accepted: 03/23/2021] [Indexed: 02/06/2023] Open
Abstract
Transcriptional silencing of the FMR1 gene in fragile X syndrome (FXS) leads to the loss of the RNA-binding protein FMRP. In addition to regulating mRNA translation and protein synthesis, emerging evidence suggests that FMRP acts to coordinate proliferation and differentiation during early neural development. However, whether loss of FMRP-mediated translational control is related to impaired cell fate specification in the developing human brain remains unknown. Here, we use human patient induced pluripotent stem cell (iPSC)-derived neural progenitor cells and organoids to model neurogenesis in FXS. We developed a high-throughput, in vitro assay that allows for the simultaneous quantification of protein synthesis and proliferation within defined neural subpopulations. We demonstrate that abnormal protein synthesis in FXS is coupled to altered cellular decisions to favor proliferative over neurogenic cell fates during early development. Furthermore, pharmacologic inhibition of elevated phosphoinositide 3-kinase (PI3K) signaling corrects both excess protein synthesis and cell proliferation in a subset of patient neural cells. Raj et al. developed a multiparametric assay to measure cellular and molecular phenotypes during neurogenesis in fragile X syndrome iPSC-derived neural cells. Relative to controls, FXS patient cultures have more proliferative cells with increased protein synthesis. Defects in cell fate acquisition can be normalized by inhibiting overactive PI3K signaling.
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19
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Richter JD, Zhao X. The molecular biology of FMRP: new insights into fragile X syndrome. Nat Rev Neurosci 2021; 22:209-222. [PMID: 33608673 PMCID: PMC8094212 DOI: 10.1038/s41583-021-00432-0] [Citation(s) in RCA: 136] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2021] [Indexed: 01/31/2023]
Abstract
Fragile X mental retardation protein (FMRP) is the product of the fragile X mental retardation 1 gene (FMR1), a gene that - when epigenetically inactivated by a triplet nucleotide repeat expansion - causes the neurodevelopmental disorder fragile X syndrome (FXS). FMRP is a widely expressed RNA-binding protein with activity that is essential for proper synaptic plasticity and architecture, aspects of neural function that are known to go awry in FXS. Although the neurophysiology of FXS has been described in remarkable detail, research focusing on the molecular biology of FMRP has only scratched the surface. For more than two decades, FMRP has been well established as a translational repressor; however, recent whole transcriptome and translatome analyses in mouse and human models of FXS have shown that FMRP is involved in the regulation of nearly all aspects of gene expression. The emerging mechanistic details of the mechanisms by which FMRP regulates gene expression may offer ways to design new therapies for FXS.
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Affiliation(s)
- Joel D Richter
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA.
| | - Xinyu Zhao
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA. .,Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA.
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20
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Champigny C, Morin-Parent F, Bellehumeur-Lefebvre L, Çaku A, Lepage JF, Corbin F. Combining Lovastatin and Minocycline for the Treatment of Fragile X Syndrome: Results From the LovaMiX Clinical Trial. Front Psychiatry 2021; 12:762967. [PMID: 35058813 PMCID: PMC8763805 DOI: 10.3389/fpsyt.2021.762967] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 11/29/2021] [Indexed: 11/13/2022] Open
Abstract
Background: Limited success of previous clinical trials for Fragile X syndrome (FXS) has led researchers to consider combining different drugs to correct the pleiotropic consequences caused by the absence of the Fragile X mental retardation protein (FMRP). Here, we report the results of the LovaMiX clinical trial, the first trial for FXS combining two disease-modifying drugs, lovastatin, and minocycline, which have both shown positive effects when used independently. Aim: The main goals of the study were to assess the safety and efficacy of a treatment combining lovastatin and minocycline for patients with FXS. Design: Pilot Phase II open-label clinical trial. Patients with a molecular diagnostic of FXS were first randomized to receive, in two-step titration either lovastatin or minocycline for 8 weeks, followed by dual treatment with lovastatin 40 mg and minocycline 100 mg for 2 weeks. Clinical assessments were performed at the beginning, after 8 weeks of monotherapy, and at week 20 (12 weeks of combined therapy). Outcome Measures: The primary outcome measure was the Aberrant Behavior Checklist-Community (ABC-C) global score. Secondary outcome measures included subscales of the FXS specific ABC-C (ABC-CFX), the Anxiety, Depression, and Mood Scale (ADAMS), the Social Responsiveness Scale (SRS), the Behavior Rating Inventory of Executive Functions (BRIEF), and the Vineland Adaptive Behavior Scale second edition (VABS-II). Results: Twenty-one individuals out of 22 completed the trial. There were no serious adverse events related to the use of either drugs alone or in combination, suggesting good tolerability and safety profile of the combined therapy. Significant improvement was noted on the primary outcome measure with a 40% decrease on ABC-C global score with the combined therapy. Several outcome measures also showed significance. Conclusion: The combination of lovastatin and minocycline is safe in patients for FXS individuals and appears to improve several elements of the behavior. These results set the stage for a larger, placebo-controlled double-blind clinical trial to confirm the beneficial effects of the combined therapy.
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Affiliation(s)
- Camille Champigny
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada.,Centre de Recherche du CHUS (CRCHUS), Sherbrooke, QC, Canada
| | | | - Laurence Bellehumeur-Lefebvre
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada.,Centre de Recherche du CHUS (CRCHUS), Sherbrooke, QC, Canada
| | - Artuela Çaku
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada.,Centre de Recherche du CHUS (CRCHUS), Sherbrooke, QC, Canada
| | - Jean-François Lepage
- Centre de Recherche du CHUS (CRCHUS), Sherbrooke, QC, Canada.,Faculty of Medicine and Health Sciences, Department of Pediatrics, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - François Corbin
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada.,Centre de Recherche du CHUS (CRCHUS), Sherbrooke, QC, Canada
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21
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Berry-Kravis E, Filipink RA, Frye RE, Golla S, Morris SM, Andrews H, Choo TH, Kaufmann WE. Seizures in Fragile X Syndrome: Associations and Longitudinal Analysis of a Large Clinic-Based Cohort. Front Pediatr 2021; 9:736255. [PMID: 35036394 PMCID: PMC8756611 DOI: 10.3389/fped.2021.736255] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 10/07/2021] [Indexed: 11/15/2022] Open
Abstract
Fragile X syndrome (FXS), the most common inherited cause of intellectual disability, learning disability, and autism spectrum disorder, is associated with an increased prevalence of certain medical conditions including seizures. The goal of this study was to better understand seizures in individuals with FXS using the Fragile X Online Registry with Accessible Research Database, a multisite observational study initiated in 2012 involving FXS clinics in the Fragile X Clinic and Research Consortium. Seizure data were available for 1,607 participants, mostly male (77%) and white (74.5%). The overall prevalence of at least one seizure was 12%, with this rate being significantly higher in males than females (13.7 vs. 6.2%, p < 0.001). As compared to individuals with FXS without seizures, those with seizures were more likely to have autism spectrum disorder, current sleep apnea, later acquisition of expressive language, more severe intellectual disability, hyperactivity, irritability, and stereotyped movements. The mean age of seizure onset was 6.4 (SD 6.1) years of age with the great majority (>80%) having onset of seizures which was before 10. For those with epilepsy, about half (52%) had seizures for more than 3 years. This group was found to have greater cognitive and language impairment, but not behavioral disruptions, compared with those with seizures for <3 years. Antiepileptic drugs were more often used in males (60.6%) than females (34.8%), and females more often required more than one medication. The most commonly used anticonvulsants were oxcarbazepine, valproic acid, lamotrigine, and levetiracetam. The current study is the largest and first longitudinal study ever conducted to describe seizures in FXS. Overall, this study confirms previous reports of seizures in FXS and extends previous findings by further defining the cognitive and behavioral phenotype of those with epilepsy in FXS. Future studies should further investigate the natural history of seizures in FXS and the characteristics of seizures in FXS in adulthood.
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Affiliation(s)
- Elizabeth Berry-Kravis
- Department of Pediatrics, Rush University Medical Center, Chicago, IL, United States.,Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, United States
| | - Robyn A Filipink
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Richard E Frye
- Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ, United States.,Department of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, United States
| | - Sailaja Golla
- Division of Neurodevelopmental Medicine, Department of Neurology, Thompson Autism Center, Children's Hospital of California, University of Irvine, Orange, CA, United States
| | - Stephanie M Morris
- Division of Pediatric and Developmental Neurology, Department of Neurology, Washington University in St. Louis, St. Louis, MO, United States
| | - Howard Andrews
- Department of Biostatistics, Mailman School of Public Health, Columbia University Medical Center, New York, NY, United States
| | - Tse-Hwei Choo
- Department of Psychiatry, New York State Psychiatric Institute, Columbia University Medical Center, New York, NY, United States
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22
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Schaefer TL, Ashworth AA, Tiwari D, Tomasek MP, Parkins EV, White AR, Snider A, Davenport MH, Grainger LM, Becker RA, Robinson CK, Mukherjee R, Williams MT, Gibson JR, Huber KM, Gross C, Erickson CA. GABA A Alpha 2,3 Modulation Improves Select Phenotypes in a Mouse Model of Fragile X Syndrome. Front Psychiatry 2021; 12:678090. [PMID: 34093287 PMCID: PMC8175776 DOI: 10.3389/fpsyt.2021.678090] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 04/26/2021] [Indexed: 11/22/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common cause of inherited intellectual disability. FXS is caused by functional loss of the Fragile X Protein (FXP), also known as Fragile X Mental Retardation Protein (FMRP). In humans and animal models, loss of FXP leads to sensory hypersensitivity, increased susceptibility to seizures and cortical hyperactivity. Several components of the GABAergic system, the major inhibitory system in the brain, are dysregulated in FXS, and thus modulation of GABAergic transmission was suggested and tested as a treatment strategy. However, so far, clinical trials using broad spectrum GABAA or GABAB receptor-specific agonists have not yielded broad improvement of FXS phenotypes in humans. Here, we tested a more selective strategy in Fmr1 knockout (KO) mice using the experimental drug BAER-101, which is a selective GABAA α2/α3 agonist. Our results suggest that BAER-101 reduces hyperexcitability of cortical circuits, partially corrects increased frequency-specific baseline cortical EEG power, reduces susceptibility to audiogenic seizures and improves novel object memory. Other Fmr1 KO-specific phenotypes were not improved by the drug, such as increased hippocampal dendritic spine density, open field activity and marble burying. Overall, this work shows that BAER-101 improves select phenotypes in Fmr1 KO mice and encourages further studies into the efficacy of GABAA-receptor subunit-selective agonists for the treatment of FXS.
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Affiliation(s)
- Tori L Schaefer
- Division of Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Amy A Ashworth
- Division of Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Durgesh Tiwari
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Madison P Tomasek
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Emma V Parkins
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Angela R White
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Andrew Snider
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Matthew H Davenport
- Division of Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Lindsay M Grainger
- Division of Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Robert A Becker
- Division of Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Chandler K Robinson
- Division of Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Rishav Mukherjee
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Michael T Williams
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Jay R Gibson
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Kimberly M Huber
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Christina Gross
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Craig A Erickson
- Division of Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
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23
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Verdura E, Pérez-Cano L, Sabido-Vera R, Guney E, Hyvelin JM, Durham L, Gomez-Mancilla B. Heterogeneity in Fragile X Syndrome Highlights the Need for Precision Medicine-Based Treatments. Front Psychiatry 2021; 12:722378. [PMID: 34658958 PMCID: PMC8514715 DOI: 10.3389/fpsyt.2021.722378] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 09/01/2021] [Indexed: 11/21/2022] Open
Abstract
Fragile X syndrome (FXS) is the most frequent monogenic cause of autism or intellectual disability, and research on its pathogenetic mechanisms has provided important insights on this neurodevelopmental condition. Nevertheless, after 30 years of intense research, efforts to develop treatments have been mostly unsuccessful. The aim of this review is to compile evidence from existing research pointing to clinical, genetic, and therapeutic response heterogeneity in FXS and highlight the need of implementing precision medicine-based treatments. We comment on the high genetic and phenotypic heterogeneity present in FXS, as a contributing factor to the difficulties found during drug development. Given that several clinical trials have showed a non-negligeable fraction of positive responders to drugs targeting core FXS symptoms, we propose that success of clinical trials can be achieved by tackling the underlying heterogeneity in FXS by accurately stratifying patients into drug-responder subpopulations. These precision medicine-based approaches, which can be first applied to well-defined monogenic diseases such as FXS, can also serve to define drug responder profiles based on specific biomarkers or phenotypic features that can associate patients with different genetic backgrounds to a same candidate drug, thus repositioning a same drug for a larger number of patients with NDDs.
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Affiliation(s)
- Edgard Verdura
- Discovery and Data Science (DDS) Unit, Sociedad Limitada (STALICLA SL), Barcelona, Spain
| | - Laura Pérez-Cano
- Discovery and Data Science (DDS) Unit, Sociedad Limitada (STALICLA SL), Barcelona, Spain
| | - Rubén Sabido-Vera
- Discovery and Data Science (DDS) Unit, Sociedad Limitada (STALICLA SL), Barcelona, Spain
| | - Emre Guney
- Discovery and Data Science (DDS) Unit, Sociedad Limitada (STALICLA SL), Barcelona, Spain.,Research Programme on Biomedical Informatics, Hospital del Mar Medical Research Institute (IMIM), Departament de Ciències Experimentals i de la Salut (DCEXS), Pompeu Fabra University (UPF), Barcelona, Spain
| | - Jean-Marc Hyvelin
- Drug Development Unit (DDU), Société Anonyme (STALICLA SA), Geneva, Switzerland
| | - Lynn Durham
- Discovery and Data Science (DDS) Unit, Sociedad Limitada (STALICLA SL), Barcelona, Spain.,Drug Development Unit (DDU), Société Anonyme (STALICLA SA), Geneva, Switzerland
| | - Baltazar Gomez-Mancilla
- Drug Development Unit (DDU), Société Anonyme (STALICLA SA), Geneva, Switzerland.,Department Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
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24
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Reyes ST, Mohajeri S, Krasinska K, Guo SG, Gu M, Pisani L, Rosenberg J, Spielman DM, Chin FT. GABA Measurement in a Neonatal Fragile X Syndrome Mouse Model Using 1H-Magnetic Resonance Spectroscopy and Mass Spectrometry. Front Mol Neurosci 2020; 13:612685. [PMID: 33390902 PMCID: PMC7775297 DOI: 10.3389/fnmol.2020.612685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 11/20/2020] [Indexed: 11/20/2022] Open
Abstract
Fragile X syndrome (FXS) is the leading monogenetic cause of autism spectrum disorder and inherited cause of intellectual disability that affects approximately one in 7,000 males and one in 11,000 females. In FXS, the Fmr1 gene is silenced and prevents the expression of the fragile X mental retardation protein (FMRP) that directly targets mRNA transcripts of multiple GABAA subunits. Therefore, FMRP loss adversely impacts the neuronal firing of the GABAergic system which creates an imbalance in the excitatory/inhibitory ratio within the brain. Current FXS treatment strategies focus on curing symptoms, such as anxiety or decreased social function. While treating symptoms can be helpful, incorporating non-invasive imaging to evaluate how treatments change the brain's biology may explain what molecular aberrations are associated with disease pathology. Thus, the GABAergic system is suitable to explore developing novel therapeutic strategies for FXS. To understand how the GABAergic system may be affected by this loss-of-function mutation, GABA concentrations were examined within the frontal cortex and thalamus of 5-day-old wild type and Fmr1 knockout mice using both 1H magnetic resonance imaging (1H-MRS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Our objective was to develop a reliable scanning method for neonatal mice in vivo and evaluate whether 1H-MRS is suitable to capture regional GABA concentration differences at the front end of the critical cortical period where abnormal neurodevelopment occurs due to FMRP loss is first detected. 1H-MRS quantified GABA concentrations in both frontal cortex and thalamus of wild type and Fmr1 knockout mice. To substantiate the results of our 1H-MRS studies, in vitro LC-MS/MS was also performed on brain homogenates from age-matched mice. We found significant changes in GABA concentration between the frontal cortex and thalamus within each mouse from both wild type and Fmr1 knockout mice using 1H-MRS and LC-MS/MS. Significant GABA levels were also detected in these same regions between wild type and Fmr1 knockout mice by LC-MS/MS, validating that FMRP loss directly affects the GABAergic system. Thus, these new findings support the need to develop an effective non-invasive imaging method to monitor novel GABAergic strategies aimed at treating patients with FXS.
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Affiliation(s)
- Samantha T. Reyes
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Sanaz Mohajeri
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Karolina Krasinska
- Stanford University Mass Spectrometry Laboratory, Stanford University, Stanford, CA, United States
| | - Scarlett G. Guo
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Meng Gu
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Laura Pisani
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Jarrett Rosenberg
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Daniel M. Spielman
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Frederick T. Chin
- Department of Radiology, Stanford University, Stanford, CA, United States
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25
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Prieto M, Folci A, Martin S. Post-translational modifications of the Fragile X Mental Retardation Protein in neuronal function and dysfunction. Mol Psychiatry 2020; 25:1688-1703. [PMID: 31822816 DOI: 10.1038/s41380-019-0629-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/22/2019] [Accepted: 11/27/2019] [Indexed: 12/17/2022]
Abstract
The Fragile X Mental Retardation Protein (FMRP) is an RNA-binding protein essential to the regulation of local translation at synapses. In the mammalian brain, synapses are constantly formed and eliminated throughout development to achieve functional neuronal networks. At the molecular level, thousands of proteins cooperate to accomplish efficient neuronal communication. Therefore, synaptic protein levels and their functional interactions need to be tightly regulated. FMRP generally acts as a translational repressor of its mRNA targets. FMRP is the target of several post-translational modifications (PTMs) that dynamically regulate its function. Here we provide an overview of the PTMs controlling the FMRP function and discuss how their spatiotemporal interplay contributes to the physiological regulation of FMRP. Importantly, FMRP loss-of-function leads to Fragile X syndrome (FXS), a rare genetic developmental condition causing a range of neurological alterations including intellectual disability (ID), learning and memory impairments, autistic-like features and seizures. Here, we also explore the possibility that recently reported missense mutations in the FMR1 gene disrupt the PTM homoeostasis of FMRP, thus participating in the aetiology of FXS. This suggests that the pharmacological targeting of PTMs may be a promising strategy to develop innovative therapies for patients carrying such missense mutations.
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Affiliation(s)
- Marta Prieto
- Université Côte d'Azur, CNRS, IPMC, Valbonne, France
| | | | - Stéphane Martin
- Université Côte d'Azur, INSERM, CNRS, IPMC, Valbonne, France.
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26
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Golden CEM, Breen MS, Koro L, Sonar S, Niblo K, Browne A, Burlant N, Di Marino D, De Rubeis S, Baxter MG, Buxbaum JD, Harony-Nicolas H. Deletion of the KH1 Domain of Fmr1 Leads to Transcriptional Alterations and Attentional Deficits in Rats. Cereb Cortex 2020; 29:2228-2244. [PMID: 30877790 PMCID: PMC6458915 DOI: 10.1093/cercor/bhz029] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 12/11/2018] [Accepted: 02/06/2019] [Indexed: 12/27/2022] Open
Abstract
Fragile X syndrome (FXS) is a neurodevelopmental disorder caused by mutations in the FMR1 gene. It is a leading monogenic cause of autism spectrum disorder and inherited intellectual disability and is often comorbid with attention deficits. Most FXS cases are due to an expansion of CGG repeats leading to suppressed expression of fragile X mental retardation protein (FMRP), an RNA-binding protein involved in mRNA metabolism. We found that the previously published Fmr1 knockout rat model of FXS expresses an Fmr1 transcript with an in-frame deletion of exon 8, which encodes for the K-homology (KH) RNA-binding domain, KH1. Notably, 3 pathogenic missense mutations associated with FXS lie in the KH domains. We observed that the deletion of exon 8 in rats leads to attention deficits and to alterations in transcriptional profiles within the medial prefrontal cortex (mPFC), which map to 2 weighted gene coexpression network modules. These modules are conserved in human frontal cortex and enriched for known FMRP targets. Hub genes in these modules represent potential therapeutic targets for FXS. Taken together, these findings indicate that attentional testing might be a reliable cross-species tool for investigating FXS and identify dysregulated conserved gene networks in a relevant brain region.
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Affiliation(s)
- Carla E M Golden
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Michael S Breen
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Lacin Koro
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Sankalp Sonar
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Kristi Niblo
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Andrew Browne
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Natalie Burlant
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Daniele Di Marino
- Faculty of Biomedical Sciences, Institute of Computational Science, Center for Computational Medicine in Cardiology, Università della Svizzera Italiana (USI), Lugano, Switzerland.,Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Silvia De Rubeis
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Mark G Baxter
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Joseph D Buxbaum
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Hala Harony-Nicolas
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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27
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Abstract
PURPOSE OF REVIEW Research on the pathophysiology of syndromic autism spectrum disorder (ASD) has contributed to the uncovering of mechanisms in nonsyndromic ASD. The current review aims to compare recent progress in therapeutics development for ASD with those for fragile X syndrome (FXS), the most frequent monogenic form of ASD. RECENT FINDINGS Although candidates such as oxytocin, vasopressin, and cannabinoids are being tested as novel therapeutics, it remains difficult to focus on a specific molecular target of drug development for ASD core symptoms. As the pathophysiology of FXS has been well described as having a causal gene, fragile X mental retardation-1, development of therapeutic agents for FXS is focused on specific molecular targets, such as metabotropic glutamate receptor 5 and GABAB receptor. SUMMARY There is a large unmet medical need in ASD, a heterogeneous and clinically defined behavioral syndrome, owing to its high prevalence in the general population, lifelong cognitive and behavioral deficits, and no established treatment of ASD core symptoms, such as deficits in social communication and restrictive repetitive behaviors. The molecular pathogenesis of nonsyndromic ASD is largely undefined. Lessons from initial attempts at targeted treatment development in FXS, and new designs resulting from these lessons, will inform trials in nonsyndromic ASD for development of therapeutics for its core symptoms.
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28
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Möhrle D, Fernández M, Peñagarikano O, Frick A, Allman B, Schmid S. What we can learn from a genetic rodent model about autism. Neurosci Biobehav Rev 2020; 109:29-53. [DOI: 10.1016/j.neubiorev.2019.12.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/28/2019] [Accepted: 12/10/2019] [Indexed: 12/15/2022]
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29
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Ciranna L, Costa L. Pituitary Adenylate Cyclase-Activating Polypeptide Modulates Hippocampal Synaptic Transmission and Plasticity: New Therapeutic Suggestions for Fragile X Syndrome. Front Cell Neurosci 2019; 13:524. [PMID: 31827422 PMCID: PMC6890831 DOI: 10.3389/fncel.2019.00524] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 11/08/2019] [Indexed: 12/13/2022] Open
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) modulates glutamatergic synaptic transmission and plasticity in the hippocampus, a brain area with a key role in learning and memory. In agreement, several studies have demonstrated that PACAP modulates learning in physiological conditions. Recent publications show reduced PACAP levels and/or alterations in PACAP receptor expression in different conditions associated with cognitive disability. It is noteworthy that PACAP administration rescued impaired synaptic plasticity and learning in animal models of aging, Alzheimer's disease, Parkinson's disease, and Huntington's chorea. In this context, results from our laboratory demonstrate that PACAP rescued metabotropic glutamate receptor-mediated synaptic plasticity in the hippocampus of a mouse model of fragile X syndrome (FXS), a genetic form of intellectual disability. PACAP is actively transported through the blood-brain barrier and reaches the brain following intranasal or intravenous administration. Besides, new studies have identified synthetic PACAP analog peptides with improved selectivity and pharmacokinetic properties with respect to the native peptide. Our review supports the shared idea that pharmacological activation of PACAP receptors might be beneficial for brain pathologies with cognitive disability. In addition, we suggest that the effects of PACAP treatment might be further studied as a possible therapy in FXS.
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Affiliation(s)
- Lucia Ciranna
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Lara Costa
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
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30
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Hoffmann A, Krause SE, Wuu J, Leurgans S, Guter SJ, Block SS, Salt J, Cook E, Maino DM, Berry-Kravis E. Vocabulary comprehension in adults with fragile X syndrome (FXS). J Neurodev Disord 2019; 11:25. [PMID: 31619160 PMCID: PMC6796341 DOI: 10.1186/s11689-019-9285-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 09/09/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Receptive and expressive vocabulary in adult and adolescent males with fragile X syndrome (FXS) have been shown as significantly lower than their chronological age; however, receptive vocabulary has been considered a strength relative to mental age. This has not been formally examined, however, and data are needed to compare receptive vocabulary with other language skills and with mental age in individuals with FXS. This is especially important as vocabulary measures are sometimes used as a proxy to estimate language ability. METHODS This preliminary study examined receptive vocabulary, global language, and cognitive skills in 42 adults (33 males and 9 females) with FXS as a portion of the baseline evaluation prior to randomization in a clinical trial of ampakine CX516. The battery of standardized tests addressed receptive vocabulary with the Peabody Picture Vocabulary Test, Third Edition (PPVT-III), receptive and expressive language (termed henceforth as global language) via the Preschool Language Scale, Fourth Edition or the Clinical Evaluation of Language Fundamentals, Third Edition, and non-verbal cognition via the Stanford-Binet Intelligence Scales, Fourth Edition (SB-IV). RESULTS Results showed (1) significantly higher receptive vocabulary than global language, (2) significantly better receptive vocabulary than non-verbal cognition, (3) equivalent non-verbal cognition and global language, and (4) severity of autism symptomatology was not correlated to receptive vocabulary or global language once non-verbal cognition was removed as factor. The scores from the PPVT-III did not represent the global language skills in our sample of adults with FXS. CONCLUSIONS Findings from this investigation strongly suggest that the PPVT-III should not be used as a screening tool for language levels or cognitive function in clinical studies since the scores from the PPVT-III were not representative of global language or non-verbal cognitive skills in adults with intellectual disabilities. This finding is critical in order to understand how to evaluate, as well as to treat, language in individuals with FXS. Development of efficient and appropriate tools to measure language, cognition, and behavior in individuals with FXS is essential.
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Affiliation(s)
- Anne Hoffmann
- Departments of Pediatrics and Communication Disorders and Sciences, Rush University, 600 N. Paulina, 1016A AAC, Chicago, IL, 60612, USA.
| | - Sue Ellen Krause
- Krause Speech and Language Services, 233 E. Erie Street, Suite 815, Chicago, IL, 60611, USA
| | - Joanne Wuu
- Department of Neurology, University of Miami Miller School of Medicine, 1120 NW 14th Street, Rm 1345, Miami, FL, 33136, USA
| | - Sue Leurgans
- Departments of Neurological Sciences, Rush University, 1750 West Harrison, Chicago, IL, 60612, USA
| | - Stephen J Guter
- University of Illinois at Chicago, Institute for Juvenile Research, 1747 W. Roosevelt Road, Room 155, Chicago, IL, 60608, USA
| | - Sandra S Block
- Illinois College of Optometry, 3241 S. Michigan Avenue, Chicago, IL, 60616, USA
| | - Jeff Salt
- Have Dreams, 515 Busse Highway, Suite 150, Park Ridge, IL, 60068, USA
| | - Edwin Cook
- Department of Psychiatry, University of Illinois at Chicago, 1747 W. Roosevelt Road, Room 155, Chicago, IL, 60608, USA
| | - Dominick M Maino
- Illinois College of Optometry, 3241 S. Michigan Avenue, Chicago, IL, 60616, USA
| | - Elizabeth Berry-Kravis
- Departments of Pediatrics, Neurological Sciences and Biochemistry, Rush University, 1725 W. Harrison Street, Suite 710, Chicago, IL, 60612, USA
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31
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A single early-life seizure results in long-term behavioral changes in the adult Fmr1 knockout mouse. Epilepsy Res 2019; 157:106193. [PMID: 31520894 DOI: 10.1016/j.eplepsyres.2019.106193] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 08/06/2019] [Accepted: 08/28/2019] [Indexed: 12/20/2022]
Abstract
Fragile X syndrome (FXS) is the leading cause of inherited intellectual disability and a significant genetic contributor to Autism spectrum disorder. In addition to autistic-like phenotypes, individuals with FXS are subject to developing numerous comorbidities, one of the most prevalent being seizures. In the present study, we investigated how a single early-life seizure superimposed on a genetic condition impacts the autistic-like behavioral phenotype of the mouse. We induced status epilepticus (SE) on postnatal day (PD) 10 in Fmr1 wild type (WT) and knockout (KO) mice. We then tested the mice in a battery of behavioral tests during adulthood (PD90) to examine the long-term impact of an early-life seizure. Our findings replicated prior work that reported a single instance of SE results in behavioral deficits, including increases in repetitive behavior, enhanced hippocampal-dependent learning, and reduced sociability and prepulse inhibition (p < 0.05). We also observed genotypic differences characteristic of the FXS phenotype in Fmr1 KO mice, such as enhanced prepulse inhibition and repetitive behavior, hyperactivity, and reduced startle responses (p < 0.05). Superimposing a seizure on deletion of Fmr1 significantly impacted repetitive behavior in a nosepoke task. Specifically, a single early-life seizure increased consecutive nose poking behavior in the task in WT mice (p < 0.05), yet seizures did not exacerbate the elevated stereotypy observed in Fmr1 KO mice (p > 0.05). Overall, these findings help to elucidate how seizures in a critical period of development can impact long-term behavioral manifestations caused by underlying gene mutations in Fmr1. Utilizing double-hit models, such as superimposing seizures on the Fmr1 mutation, can help to enhance our understanding of comorbidities in disease models.
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32
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Towards Mechanism-Based Treatments for Fragile X Syndrome. Brain Sci 2019; 9:brainsci9080202. [PMID: 31426300 PMCID: PMC6721292 DOI: 10.3390/brainsci9080202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 08/14/2019] [Indexed: 11/17/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common heritable form of intellectual disability, as well as the most common known monogenic cause of autism spectrum disorder (ASD), affecting 1 in 4000-8000 people worldwide [...].
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33
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Cogram P, Deacon RMJ, Warner-Schmidt JL, von Schimmelmann MJ, Abrahams BS, During MJ. Gaboxadol Normalizes Behavioral Abnormalities in a Mouse Model of Fragile X Syndrome. Front Behav Neurosci 2019; 13:141. [PMID: 31293404 PMCID: PMC6603241 DOI: 10.3389/fnbeh.2019.00141] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 06/07/2019] [Indexed: 12/11/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common inherited form of intellectual disability and autism. FXS is also accompanied by attention problems, hyperactivity, anxiety, aggression, poor sleep, repetitive behaviors, and self-injury. Recent work supports the role of γ-aminobutyric-acid (GABA), the primary inhibitory neurotransmitter in the brain, in mediating symptoms of FXS. Deficits in GABA machinery have been observed in a mouse model of FXS, including a loss of tonic inhibition in the amygdala, which is mediated by extrasynaptic GABAA receptors. Humans with FXS also show reduced GABAA receptor availability. Here, we sought to evaluate the potential of gaboxadol (also called OV101 and THIP), a selective and potent agonist for delta-subunit-containing extrasynaptic GABAA receptors (dSEGA), as a therapeutic agent for FXS by assessing its ability to normalize aberrant behaviors in a relatively uncharacterized mouse model of FXS (Fmr1 KO2 mice). Four behavioral domains (hyperactivity, anxiety, aggression, and repetitive behaviors) were probed using a battery of behavioral assays. The results showed that Fmr1 KO2 mice were hyperactive, had abnormal anxiety-like behavior, were more irritable and aggressive, and had an increased frequency of repetitive behaviors compared to wild-type (WT) littermates, which are all behavioral deficits reminiscent of individuals with FXS. Treatment with gaboxadol normalized all of the aberrant behaviors observed in Fmr1 KO2 mice back to WT levels, providing evidence of its potential benefit for treating FXS. We show that the potentiation of extrasynaptic GABA receptors alone, by gaboxadol, is sufficient to normalize numerous behavioral deficits in the FXS model using endpoints that are directly translatable to the clinical presentation of FXS. Taken together, these data support the future evaluation of gaboxadol in individuals with FXS, particularly with regard to symptoms of hyperactivity, anxiety, irritability, aggression, and repetitive behaviors.
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Affiliation(s)
- Patricia Cogram
- FRAXA-DVI, FRAXA Research Foundation, Boston, MA, United States.,Centre for Systems Biotechnology, Biomedicine Division, Fraunhofer-Gesellschaft, Santiago, Chile.,GEN.DDI Limited, London, United Kingdom.,Institute of Ecology and Biodiversity (IEB), University of Chile, Santiago, Chile
| | - Robert M J Deacon
- FRAXA-DVI, FRAXA Research Foundation, Boston, MA, United States.,Centre for Systems Biotechnology, Biomedicine Division, Fraunhofer-Gesellschaft, Santiago, Chile.,GEN.DDI Limited, London, United Kingdom.,Institute of Ecology and Biodiversity (IEB), University of Chile, Santiago, Chile
| | | | | | - Brett S Abrahams
- Ovid Therapeutics, New York, NY, United States.,Department of Genetics and Neuroscience, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Matthew J During
- Ovid Therapeutics, New York, NY, United States.,Department of Neurological Surgery and Molecular Virology, Immunology and Medical Genetics, Ohio State University College of Medicine, Columbus, OH, United States
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Cannabidiol (CBD) reduces anxiety-related behavior in mice via an FMRP-independent mechanism. Pharmacol Biochem Behav 2019; 181:93-100. [DOI: 10.1016/j.pbb.2019.05.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 04/21/2019] [Accepted: 05/01/2019] [Indexed: 11/18/2022]
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35
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Gilchrist KH, Hegarty-Craver M, Christian RB, Grego S, Kies AC, Wheeler AC. Automated Detection of Repetitive Motor Behaviors as an Outcome Measurement in Intellectual and Developmental Disabilities. J Autism Dev Disord 2019; 48:1458-1466. [PMID: 29164446 DOI: 10.1007/s10803-017-3408-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Repetitive sensory motor behaviors are a direct target for clinical treatment and a potential treatment endpoint for individuals with intellectual or developmental disabilities. By removing the burden associated with video annotation or direct observation, automated detection of stereotypy would allow for longer term monitoring in ecologic settings. We report automated detection of common stereotypical motor movements using commercially available accelerometers affixed to the body and a generalizable detection algorithm. The method achieved a sensitivity of 80% for body rocking and 93% for hand flapping without individualized algorithm training or foreknowledge of subject's specific movements. This approach is well-suited for implementation in a continuous monitoring system outside of a clinical setting.
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Affiliation(s)
- Kristin H Gilchrist
- RTI International, 3040 E. Cornwallis Road, Research Triangle Park, NC, 27709, USA.
| | | | - Robert B Christian
- Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC, USA
| | - Sonia Grego
- RTI International, 3040 E. Cornwallis Road, Research Triangle Park, NC, 27709, USA
| | - Ashley C Kies
- Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC, USA.,Child and Family Development, Inc., Charlotte, NC, USA
| | - Anne C Wheeler
- RTI International, 3040 E. Cornwallis Road, Research Triangle Park, NC, 27709, USA
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36
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Zafarullah M, Tassone F. Molecular Biomarkers in Fragile X Syndrome. Brain Sci 2019; 9:brainsci9050096. [PMID: 31035599 PMCID: PMC6562871 DOI: 10.3390/brainsci9050096] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/22/2019] [Accepted: 04/24/2019] [Indexed: 01/01/2023] Open
Abstract
Fragile X syndrome (FXS) is the most common inherited form of intellectual disability (ID) and a known monogenic cause of autism spectrum disorder (ASD). It is a trinucleotide repeat disorder, in which more than 200 CGG repeats in the 5’ untranslated region (UTR) of the fragile X mental retardation 1 (FMR1) gene causes methylation of the promoter with consequent silencing of the gene, ultimately leading to the loss of the encoded fragile X mental retardation 1 protein, FMRP. FMRP is an RNA binding protein that plays a primary role as a repressor of translation of various mRNAs, many of which are involved in the maintenance and development of neuronal synaptic function and plasticity. In addition to intellectual disability, patients with FXS face several behavioral challenges, including anxiety, hyperactivity, seizures, repetitive behavior, and problems with executive and language performance. Currently, there is no cure or approved medication for the treatment of the underlying causes of FXS, but in the past few years, our knowledge about the proteins and pathways that are dysregulated by the loss of FMRP has increased, leading to clinical trials and to the path of developing molecular biomarkers for identifying potential targets for therapies. In this paper, we review candidate molecular biomarkers that have been identified in preclinical studies in the FXS mouse animal model and are now under validation for human applications or have already made their way to clinical trials.
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Affiliation(s)
- Marwa Zafarullah
- Department of Biochemistry and Molecular Medicine, University of California Davis, School of Medicine, Sacramento, 95817 CA, USA.
| | - Flora Tassone
- Department of Biochemistry and Molecular Medicine, University of California Davis, School of Medicine, Sacramento, 95817 CA, USA.
- MIND Institute, University of California Davis Medical Center, Sacramento, 95817 CA, USA.
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Jalnapurkar I, Cochran DM, Frazier JA. New Therapeutic Options for Fragile X Syndrome. Curr Treat Options Neurol 2019; 21:12. [PMID: 30809735 DOI: 10.1007/s11940-019-0551-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE OF REVIEW The purpose of this review is to provide an overview of current research and clinical practice guidelines in fragile X syndrome (FXS) with regard to therapeutic approaches in the management of this condition. The authors summarize and discuss findings from relevant preclinical studies and results from clinical trials in human subjects with FXS. Additionally, we provide an outline of the basic framework for understanding and providing educational and psychosocial supports for these individuals. RECENT FINDINGS Current treatments in FXS are largely symptom based and focused on managing associated psychiatric and behavioral co-morbidities. While data from animal studies has been promising in providing targeted treatments to correct the underlying deficits at the cellular level, there have not been as robust findings in human trials. There are several targeted treatments for FXS currently under development. Individuals with FXS present with several behavioral challenges including anxiety, social withdrawal, ADHD, hyperarousal, self-injury, and aggression. Therapeutic services are often necessary, such as behavioral intervention, speech and language therapy, occupational therapy, and individualized educational support; adjunctive psychopharmacologic treatment is often helpful as well. It is important to address these symptoms and weigh the evidence for the use of medications that target the underlying neurobiology and pathophysiology of the syndrome.
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Affiliation(s)
- Isha Jalnapurkar
- Eunice Kennedy Shriver Center, University of Massachusetts Medical School, 55 Lake Ave N, Worcester, MA, 01655, USA. .,Department of Psychiatry, University of Massachusetts Medical School, 55 Lake Ave N, Worcester, MA, 01655, USA.
| | - David M Cochran
- Eunice Kennedy Shriver Center, University of Massachusetts Medical School, 55 Lake Ave N, Worcester, MA, 01655, USA.,Department of Psychiatry, University of Massachusetts Medical School, 55 Lake Ave N, Worcester, MA, 01655, USA
| | - Jean A Frazier
- Eunice Kennedy Shriver Center, University of Massachusetts Medical School, 55 Lake Ave N, Worcester, MA, 01655, USA.,Department of Psychiatry, University of Massachusetts Medical School, 55 Lake Ave N, Worcester, MA, 01655, USA
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Jacquemont S, Pacini L, Jønch AE, Cencelli G, Rozenberg I, He Y, D'Andrea L, Pedini G, Eldeeb M, Willemsen R, Gasparini F, Tassone F, Hagerman R, Gomez-Mancilla B, Bagni C. Protein synthesis levels are increased in a subset of individuals with fragile X syndrome. Hum Mol Genet 2019; 27:2039-2051. [PMID: 29590342 PMCID: PMC5985734 DOI: 10.1093/hmg/ddy099] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 03/15/2018] [Indexed: 12/15/2022] Open
Abstract
Fragile X syndrome (FXS) is a monogenic form of intellectual disability and autism spectrum disorder caused by the absence of the fragile X mental retardation protein (FMRP). In biological models for the disease, this leads to upregulated mRNA translation and as a consequence, deficits in synaptic architecture and plasticity. Preclinical studies revealed that pharmacological interventions restore those deficits, which are thought to mediate the FXS cognitive and behavioral symptoms. Here, we characterized the de novo rate of protein synthesis in patients with FXS and their relationship with clinical severity. We measured the rate of protein synthesis in fibroblasts derived from 32 individuals with FXS and from 17 controls as well as in fibroblasts and primary neurons of 27 Fmr1 KO mice and 20 controls. Here, we show that levels of protein synthesis are increased in fibroblasts of individuals with FXS and Fmr1 KO mice. However, this cellular phenotype displays a broad distribution and a proportion of fragile X individuals and Fmr1 KO mice do not show increased levels of protein synthesis, having measures in the normal range. Because the same Fmr1 KO animal measures in fibroblasts predict those in neurons we suggest the validity of this peripheral biomarker. Our study offers a potential explanation for the comprehensive drug development program undertaken thus far yielding negative results and suggests that a significant proportion, but not all individuals with FXS, may benefit from the reduction of excessive levels of protein synthesis.
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Affiliation(s)
- Sébastien Jacquemont
- Sainte-Justine University Hospital Research Centre, Montreal, QC H3T 1C5.,University of Montreal, Montreal, QC H3T 1J4, Canada
| | - Laura Pacini
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Aia E Jønch
- Department of Clinical Genetics, Odense University Hospital.,Human Genetics, Department of Clinical Research, University of Southern Denmark, 5000 Odense, Denmark
| | - Giulia Cencelli
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Izabela Rozenberg
- Neuroscience Translational Medicine, Novartis Institutes for Biomedical Research, Novartis Pharma AG, 4056 Basel, Switzerland
| | - Yunsheng He
- Biomarker Development, Novartis Institutes for Biomedical Research, Cambridge, MA 02139, USA
| | - Laura D'Andrea
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Giorgia Pedini
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Marwa Eldeeb
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis Medical Center, Sacramento, CA 95817, USA
| | - Rob Willemsen
- Department of Clinical Genetics, Erasmus Medical Center, 1738, 3000DR Rotterdam, The Netherlands
| | - Fabrizio Gasparini
- Neuroscience Discovery, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Flora Tassone
- Department of Biochemistry and Molecular Medicine and Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, Sacramento, CA 95817, USA
| | - Randi Hagerman
- Department of Pediatric and Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, School of Medicine, Sacramento, CA 95817, USA
| | - Baltazar Gomez-Mancilla
- Neuroscience Translational Medicine, Novartis Institutes for Biomedical Research, Novartis Pharma AG, 4056 Basel, Switzerland.,Department of Neurology and Neurosurgery, McGill University, Montreal, QC H3A 0G4, Canada
| | - Claudia Bagni
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy.,Department of Fundamental Neuroscience, University of Lausanne, 1005 Lausanne, Switzerland
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Weber JD, Smith E, Berry-Kravis E, Cadavid D, Hessl D, Erickson C. Voice of People with Fragile X Syndrome and Their Families: Reports from a Survey on Treatment Priorities. Brain Sci 2019; 9:brainsci9020018. [PMID: 30678024 PMCID: PMC6406416 DOI: 10.3390/brainsci9020018] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/16/2019] [Accepted: 01/16/2019] [Indexed: 01/29/2023] Open
Abstract
To date, there has been limited research on the primary concerns and treatment priorities for individuals with fragile X syndrome (FXS) and their families. The National Fragile X Foundation in collaboration with clinical investigators from industry and academia constructed a survey to investigate the main symptoms, daily living challenges, family impact, and treatment priorities for individuals with FXS and their families, which was then distributed to a large mailing list. The survey included both structured questions focused on ranking difficulties as well as qualitative analysis of open-ended questions. It was completed by 467 participants, including 439 family members or caretakers (family members/caretakers) of someone with FXS, 20 professionals who work with a person with FXS, and 8 individuals with FXS. Respondents indicated three main general areas of concern: Anxiety, behavioral problems, and learning difficulties. Important differences were noted, based on the sex and age of the individual with FXS. The results highlight the top priorities for treatment development for family members/caretakers, as well as a small group of professionals, and an even smaller group of individuals with FXS, while demonstrating challenges with "voice of the patient" research in FXS.
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Affiliation(s)
| | - Elizabeth Smith
- Cincinnati Children's Hospital Medical Center Division of Child & Adolescent Psychiatry, Cincinnati, OH 45229, USA.
| | - Elizabeth Berry-Kravis
- Departments of Pediatrics, Neurological Sciences, Biochemistry, Rush University Medical Center, Chicago, IL 60612, USA.
| | | | - David Hessl
- MIND Institute and Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA 95817, USA.
| | - Craig Erickson
- Cincinnati Children's Hospital Medical Center, Division of Child & Adolescent Psychiatry and the University of Cincinnati College of Medicine Department of Psychiatry and Behavioral Neuroscience, Cincinnati, OH 45229, USA.
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40
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Hessl D, Harvey D, Sansone S, Crestodina C, Chin J, Joshi R, Hagerman RJ, Berry‐Kravis E. Effects of mavoglurant on visual attention and pupil reactivity while viewing photographs of faces in Fragile X Syndrome. PLoS One 2019; 14:e0209984. [PMID: 30653533 PMCID: PMC6336311 DOI: 10.1371/journal.pone.0209984] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 12/14/2018] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Numerous preclinical studies have supported the theory that enhanced activation of mGluR5 signaling, due to the absence or reduction of the FMR1 protein, contributes to cognitive and behavioral deficits in patients with fragile X syndrome (FXS). However multiple phase 2 controlled trials in patients with FXS have failed to demonstrate efficacy of compounds that negatively modulate mGluR5, including two phase 2b randomized controlled trials (RCT) of mavoglurant (AFQ056, Novartis Pharma AG), when the primary measures of interest were behavioral ratings. This has cast some doubt onto the translation of the mGluR5 theory from animal models to humans with the disorder. METHODS We evaluated social gaze behavior-a key phenotypic feature of the disorder-and sympathetic nervous system influence on pupil size using a previously-validated eye tracking paradigm as a biobehavioral probe, in 57 adolescent or adult patients with FXS at baseline and following three months of blinded treatment with one of three doses of mavoglurant or placebo, within the context of the AFQ056 RCTs. RESULTS Patients with FXS treated with mavoglurant demonstrated increased total absolute looking time and number of fixations to the eye region while viewing human faces relative to baseline, and compared to those treated with placebo. In addition, patients had greater pupil reactivity to faces relative to baseline following mavoglurant treatment compared to placebo. DISCUSSION The study shows that negative modulation of mGluR5 activity improves eye gaze behavior and alters sympathetically-driven reactivity to faces in patients with FXS, providing preliminary evidence of this drug's impact on behavior in humans with the disorder.
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Affiliation(s)
- David Hessl
- MIND Institute, University of California Davis Medical Center, Sacramento, California, United States of America
- Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, California, United States of America
| | - Danielle Harvey
- Division of Biostatistics, Department of Public Health Sciences, University of California Davis School of Medicine, Davis, CA, United States of America
| | - Stephanie Sansone
- MIND Institute, University of California Davis Medical Center, Sacramento, California, United States of America
- Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, California, United States of America
| | - Crystal Crestodina
- Department of Pediatrics, Rush University Medical Center, Chicago, IL, United States of America
| | - Jamie Chin
- Department of Pediatrics, Rush University Medical Center, Chicago, IL, United States of America
| | - Reshma Joshi
- Department of Pediatrics, Rush University Medical Center, Chicago, IL, United States of America
| | - Randi J. Hagerman
- MIND Institute, University of California Davis Medical Center, Sacramento, California, United States of America
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, California, United States of America
| | - Elizabeth Berry‐Kravis
- Department of Pediatrics, Rush University Medical Center, Chicago, IL, United States of America
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, United States of America
- Department of Biochemistry, Rush University Medical Center, Chicago, IL, United States of America
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41
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Gross C, Banerjee A, Tiwari D, Longo F, White AR, Allen AG, Schroeder-Carter LM, Krzeski JC, Elsayed NA, Puckett R, Klann E, Rivero RA, Gourley SL, Bassell GJ. Isoform-selective phosphoinositide 3-kinase inhibition ameliorates a broad range of fragile X syndrome-associated deficits in a mouse model. Neuropsychopharmacology 2019; 44:324-333. [PMID: 30061744 PMCID: PMC6300538 DOI: 10.1038/s41386-018-0150-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 06/07/2018] [Accepted: 07/01/2018] [Indexed: 12/19/2022]
Abstract
Defects in the phosphoinositide 3-kinase (PI3K) pathway are shared characteristics in several brain disorders, including the inherited intellectual disability and autism spectrum disorder, fragile X syndrome (FXS). PI3K signaling therefore could serve as a therapeutic target for FXS and other brain disorders. However, broad inhibition of such a central signal transduction pathway involved in essential cellular functions may produce deleterious side effects. Pharmacological strategies that selectively correct the overactive components of the PI3K pathway while leaving other parts of the pathway intact may overcome these challenges. Here, we provide the first evidence that disease mechanism-based PI3K isoform-specific inhibition may be a viable treatment option for FXS. FXS is caused by loss of the fragile X mental retardation protein (FMRP), which translationally represses specific messenger RNAs, including the PI3K catalytic isoform p110β. FMRP deficiency increases p110β protein levels and activity in FXS mouse models and in cells from subjects with FXS. Here, we show that a novel, brain-permeable p110β-specific inhibitor, GSK2702926A, ameliorates FXS-associated phenotypes on molecular, cellular, behavioral, and cognitive levels in two different FMRP-deficient mouse models. Rescued phenotypes included increased PI3K downstream signaling, protein synthesis rates, and dendritic spine density, as well as impaired social interaction and higher-order cognition. Several p110β-selective inhibitors, for example, a molecule from the same chemotype as GSK2702926A, are currently being evaluated in clinical trials to treat cancer. Our results suggest that repurposing p110β inhibitors to treat cognitive and behavioral defects may be a promising disease-modifying strategy for FXS and other brain disorders.
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Affiliation(s)
- Christina Gross
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA. .,Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, OH, 45229, USA.
| | - Anwesha Banerjee
- 0000 0001 0941 6502grid.189967.8Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322 USA
| | - Durgesh Tiwari
- 0000 0000 9025 8099grid.239573.9Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229 USA
| | - Francesco Longo
- 0000 0004 1936 8753grid.137628.9Center for Neural Science, New York University, New York, NY 10003 USA
| | - Angela R. White
- 0000 0000 9025 8099grid.239573.9Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229 USA
| | - A. G. Allen
- 0000 0001 0941 6502grid.189967.8Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322 USA ,0000 0001 0941 6502grid.189967.8Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30322 USA
| | - Lindsay M. Schroeder-Carter
- 0000 0000 9025 8099grid.239573.9Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229 USA
| | - Joseph C. Krzeski
- 0000 0000 9025 8099grid.239573.9Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229 USA
| | - Nada A. Elsayed
- 0000 0000 9025 8099grid.239573.9Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229 USA
| | - Rosemary Puckett
- 0000 0004 1936 8753grid.137628.9Center for Neural Science, New York University, New York, NY 10003 USA
| | - Eric Klann
- 0000 0004 1936 8753grid.137628.9Center for Neural Science, New York University, New York, NY 10003 USA
| | - Ralph A. Rivero
- 0000 0004 0393 4335grid.418019.5GlaxoSmithKline, Collegeville, PA 19426 USA
| | - Shannon L. Gourley
- 0000 0001 0941 6502grid.189967.8Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322 USA ,0000 0001 0941 6502grid.189967.8Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30322 USA ,0000 0001 0941 6502grid.189967.8Yerkes National Primate Research Center, Emory University School of Medicine, Atlanta, GA 30329 USA
| | - Gary J. Bassell
- 0000 0001 0941 6502grid.189967.8Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322 USA ,0000 0001 0941 6502grid.189967.8Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322 USA
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Lee AW, Ventola P, Budimirovic D, Berry-Kravis E, Visootsak J. Clinical Development of Targeted Fragile X Syndrome Treatments: An Industry Perspective. Brain Sci 2018; 8:E214. [PMID: 30563047 PMCID: PMC6315847 DOI: 10.3390/brainsci8120214] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 11/28/2018] [Accepted: 11/30/2018] [Indexed: 01/03/2023] Open
Abstract
Fragile X syndrome (FXS) is the leading known cause of inherited intellectual disability and autism spectrum disorder. It is caused by a mutation of the fragile X mental retardation 1 (FMR1) gene, resulting in a deficit of fragile X mental retardation protein (FMRP). The clinical presentation of FXS is variable, and is typically associated with developmental delays, intellectual disability, a wide range of behavioral issues, and certain identifying physical features. Over the past 25 years, researchers have worked to understand the complex relationship between FMRP deficiency and the symptoms of FXS and, in the process, have identified several potential targeted therapeutics, some of which have been tested in clinical trials. Whereas most of the basic research to date has been led by experts at academic institutions, the pharmaceutical industry is becoming increasingly involved with not only the scientific community, but also with patient advocacy organizations, as more promising pharmacological agents are moving into the clinical stages of development. The objective of this review is to provide an industry perspective on the ongoing development of mechanism-based treatments for FXS, including identification of challenges and recommendations for future clinical trials.
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Affiliation(s)
- Anna W Lee
- Ovid Therapeutics Inc., New York, NY 10036, USA.
| | - Pamela Ventola
- Child Study Center, Yale University, New Haven, CT 06520, USA.
| | - Dejan Budimirovic
- Departments of Psychiatry and Behavioral Sciences, Kennedy Krieger Institute and Child Psychiatry, Johns Hopkins University, Baltimore, MD 21205, USA.
| | - Elizabeth Berry-Kravis
- Departments of Pediatrics, Neurological Sciences, Biochemistry, Rush University Medical Center, Chicago, IL 60612, USA.
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43
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Mavoglurant in Fragile X Syndrome: Results of two open-label, extension trials in adults and adolescents. Sci Rep 2018; 8:16970. [PMID: 30451888 PMCID: PMC6242849 DOI: 10.1038/s41598-018-34978-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 10/22/2018] [Indexed: 02/06/2023] Open
Abstract
Fragile X syndrome (FXS) is the most common monogenic cause of inherited intellectual and developmental disabilities. Mavoglurant, a selective metabotropic glutamate receptor subtype-5 antagonist, has shown positive neuronal and behavioral effects in preclinical studies, but failed to demonstrate any behavioral benefits in two 12-week, randomized, placebo-controlled, double-blind, phase IIb studies in adults and adolescents with FXS. Here we report the long-term safety (primary endpoint) and efficacy (secondary endpoint) results of the open-label extensions. Adolescent (n = 119, aged 12–19 years) and adult (n = 148, aged 18–45 years) participants received up to 100 mg bid mavoglurant for up to 34 months. Both extension studies were terminated prematurely due to lack of proven efficacy in the core studies. Mavoglurant was well tolerated with no new safety signal. Five percent of adults and 16.9 percent of adolescents discontinued treatment due to adverse events. Gradual and consistent behavioral improvements as measured by the ABC-CFX scale were observed, which were numerically superior to those seen in the placebo arm of the core studies. These two extension studies confirm the long-term safety of mavoglurant in FXS, but further investigations are required to determine whether and under which conditions the significant preclinical results obtained with mGluR5 inhibition can translate to humans.
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Abstract
PURPOSE OF REVIEW This article discusses the diagnostic evaluation of intellectual developmental disorder, comprising global developmental delay and intellectual disability in children. RECENT FINDINGS With a prevalence of 1% to 3% and substantial comorbidity, high lifetime costs, and emotional burden, intellectual developmental disorder is characterized by limitations in both intellectual functioning (IQ less than 70) and adaptive behavior starting before 18 years of age. Pinpointing the precise genetic cause is important, as it allows for accurate genetic counseling, avoidance of unnecessary testing, prognostication, and tailored management, which, for an increasing number of genetic conditions, targets the pathophysiology and improves outcomes. SUMMARY The etiology of intellectual developmental disorder is heterogeneous, which mandates a structured approach that considers family situation, test costs, yield, and potential therapeutic tractability of the identified condition. Diagnosis of an underlying genetic cause is increasingly important with the advent of new treatments. Still, in many cases, the cause remains unknown, and research is needed to elucidate its complex molecular basis.
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Mably AJ, Colgin LL. Gamma oscillations in cognitive disorders. Curr Opin Neurobiol 2018; 52:182-187. [PMID: 30121451 DOI: 10.1016/j.conb.2018.07.009] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/18/2018] [Accepted: 07/31/2018] [Indexed: 02/06/2023]
Abstract
Gamma oscillations (∼25-100 Hz) are believed to play a role in cognition. Accordingly, aberrant gamma oscillations have been observed in several cognitive disorders, including Alzheimer's disease and Fragile X syndrome. Here, we review how recent results showing abnormal gamma rhythms in Alzheimer's disease and Fragile X syndrome help reveal links between cellular disturbances and cognitive impairments. We also discuss how gamma results from rodent models of Alzheimer's disease and Fragile X syndrome may provide insights about unique functions of distinct slow (∼25-50 Hz) and fast gamma (∼55-100 Hz) subtypes. Finally, we consider studies employing brain stimulation paradigms in Alzheimer's disease and discuss how such studies may reveal causal relationships between gamma impairments and memory disturbances.
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Affiliation(s)
- Alexandra J Mably
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, 1 University Station Stop C7000, Austin, TX 78712, USA
| | - Laura Lee Colgin
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, 1 University Station Stop C7000, Austin, TX 78712, USA.
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Fragile X syndrome and fragile X-associated tremor ataxia syndrome. HANDBOOK OF CLINICAL NEUROLOGY 2018; 147:377-391. [PMID: 29325626 DOI: 10.1016/b978-0-444-63233-3.00025-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Fragile X-associated disorders encompass several conditions, which are caused by expansion mutations in the fragile X mental retardation 1 (FMR1) gene. Fragile X syndrome is the most common inherited etiology of intellectual disability and results from a full mutation or >200 CGG repeats in FMR1. It is associated with developmental delay, autism spectrum disorder, and seizures. Fragile X-associated tremor/ataxia syndrome is a progressive neurodegenerative disease that occurs in premutation carriers of 55-200 CGG repeats in FMR1 and is characterized by kinetic tremor, gait ataxia, parkinsonism, executive dysfunction, and neuropathy. Fragile X-associated primary ovarian insufficiency also occurs in premutation carrier women and manifests with infertility and early menopause. The diseases constituting fragile X-associated disorders differ mechanistically, due to the distinct molecular properties of premutation versus full mutations. Fragile X syndrome occurs when there is a lack of fragile X mental retardation protein (FMRP) due to FMR1 methylation and silencing. In fragile X-associated tremor ataxia syndrome, a toxic gain of function is postulated with the production of excess CGG repeat-containing FMR1 mRNA, abnormal translation of the repeat sequence leading to production of polyglycine, polyalanine, and other polypeptides and to outright deficits in translation leading to reduced FMRP at larger premutation sizes. The changes in underlying brain chemistry due to FMR1 mutations have led to therapeutic studies in these disorders, with some progress being made in fragile X syndrome. This paper also summarizes indications for testing, genetic counseling issues, and what the future holds for these disorders.
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Abstract
PURPOSE OF REVIEW The goal of this focused review is to describe recent studies supporting a critical role of microRNAs in the regulation of ion channels and discuss the resulting implications for the modulation of neuronal excitability in epilepsy. RECENT FINDINGS MicroRNA-induced silencing of ion channels has been shown in several different studies in recent years, and some of these reports suggest a prominent role in epilepsy. The ion channels regulated by microRNAs include ligand- and voltage-gated channels and are not only limited to the central nervous system but have also been found in the peripheral nervous system. Ion channel-targeting microRNAs can regulate the intrinsic excitability of neurons, and thus influence entire networks in the brain. Their dysregulation in epilepsy may contribute to the disease phenotype. More research is needed to better understand the molecular mechanisms of how microRNAs regulate ion channels to control neuronal excitability, and how these processes are altered in epilepsy.
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Handling FMRP and its molecular partners: Structural insights into Fragile X Syndrome. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 141:3-14. [PMID: 30905341 DOI: 10.1016/j.pbiomolbio.2018.07.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 07/01/2018] [Indexed: 12/29/2022]
Abstract
Fragile X Mental Retardation Protein (FMRP) is a RNA-binding protein (RBP) known to control different steps of mRNA metabolism, even though its complete function is not fully understood yet. Lack or mutations of FMRP lead to Fragile X Syndrome (FXS), the most common form of inherited intellectual disability and a leading monogenic cause of autism spectrum disorder (ASD). It is well established that FMRP has a multi-domain architecture, a feature that allows this RBP to be engaged in a large interaction network with numerous proteins and mRNAs or non-coding RNAs. Insights into the three-dimensional (3D) structure of parts of its three domains (N-terminus, central domain and C-terminus) were obtained using Nuclear Magnetic Resonance and X-ray diffraction, but the complete 3D arrangement of each domain with respect to the others is still missing. Here, we review the structural features of FMRP and of the network of its protein and RNA interactions. Understanding these aspects is the first necessary step towards the design of novel compounds for new therapeutic interventions in FXS.
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Dahlhaus R. Of Men and Mice: Modeling the Fragile X Syndrome. Front Mol Neurosci 2018; 11:41. [PMID: 29599705 PMCID: PMC5862809 DOI: 10.3389/fnmol.2018.00041] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 01/31/2018] [Indexed: 12/26/2022] Open
Abstract
The Fragile X Syndrome (FXS) is one of the most common forms of inherited intellectual disability in all human societies. Caused by the transcriptional silencing of a single gene, the fragile x mental retardation gene FMR1, FXS is characterized by a variety of symptoms, which range from mental disabilities to autism and epilepsy. More than 20 years ago, a first animal model was described, the Fmr1 knock-out mouse. Several other models have been developed since then, including conditional knock-out mice, knock-out rats, a zebrafish and a drosophila model. Using these model systems, various targets for potential pharmaceutical treatments have been identified and many treatments have been shown to be efficient in preclinical studies. However, all attempts to turn these findings into a therapy for patients have failed thus far. In this review, I will discuss underlying difficulties and address potential alternatives for our future research.
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Affiliation(s)
- Regina Dahlhaus
- Institute for Biochemistry, Emil-Fischer Centre, University of Erlangen-Nürnberg, Erlangen, Germany
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McDuffie A, Banasik A, Bullard L, Nelson S, Feigles RT, Hagerman R, Abbeduto L. Distance delivery of a spoken language intervention for school-aged and adolescent boys with fragile X syndrome. Dev Neurorehabil 2018; 21:48-63. [PMID: 28956679 PMCID: PMC5986725 DOI: 10.1080/17518423.2017.1369189] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A small randomized group design (N = 20) was used to examine a parent-implemented intervention designed to improve the spoken language skills of school-aged and adolescent boys with FXS, the leading cause of inherited intellectual disability. The intervention was implemented by speech-language pathologists who used distance video-teleconferencing to deliver the intervention. The intervention taught mothers to use a set of language facilitation strategies while interacting with their children in the context of shared story-telling. Treatment group mothers significantly improved their use of the targeted intervention strategies. Children in the treatment group increased the duration of engagement in the shared story-telling activity as well as use of utterances that maintained the topic of the story. Children also showed increases in lexical diversity, but not in grammatical complexity.
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Affiliation(s)
- Andrea McDuffie
- MIND Institute, University of California, Sacramento, CA, USA,Department of Psychiatry and Behavioral Sciences, University of California, Sacramento, CA, USA
| | - Amy Banasik
- MIND Institute, University of California, Sacramento, CA, USA,Department of Psychiatry and Behavioral Sciences, University of California, Sacramento, CA, USA
| | - Lauren Bullard
- MIND Institute, University of California, Sacramento, CA, USA,Department of Psychiatry and Behavioral Sciences, University of California, Sacramento, CA, USA
| | - Sarah Nelson
- MIND Institute, University of California, Sacramento, CA, USA,Department of Psychiatry and Behavioral Sciences, University of California, Sacramento, CA, USA
| | - Robyn Tempero Feigles
- MIND Institute, University of California, Sacramento, CA, USA,Department of Psychiatry and Behavioral Sciences, University of California, Sacramento, CA, USA
| | - Randi Hagerman
- MIND Institute, University of California, Sacramento, CA, USA,Department of Pediatrics, University of California, Sacramento CA, USA
| | - Leonard Abbeduto
- MIND Institute, University of California, Sacramento, CA, USA,Department of Psychiatry and Behavioral Sciences, University of California, Sacramento, CA, USA
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