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Ji Y, Chen R, Wang Q, Wei Q, Tao R, Li B. Leveraging Gene-Level Prediction as Informative Covariate in Hypothesis Weighting Improves Power for Rare Variant Association Studies. Genes (Basel) 2022; 13:genes13020381. [PMID: 35205424 PMCID: PMC8872452 DOI: 10.3390/genes13020381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/31/2022] [Accepted: 02/09/2022] [Indexed: 02/05/2023] Open
Abstract
Gene-based rare variant association studies (RVASs) have low power due to the infrequency of rare variants and the large multiple testing burden. To correct for multiple testing, traditional false discovery rate (FDR) procedures which depend solely on P-values are often used. Recently, Independent Hypothesis Weighting (IHW) was developed to improve the detection power while maintaining FDR control by leveraging prior information for each hypothesis. Here, we present a framework to increase power of gene-based RVASs by incorporating prior information using IHW. We first build supervised machine learning models to assign each gene a prediction score that measures its disease risk, using the input of multiple biological features, fed with high-confidence risk genes and local background genes selected near GWAS significant loci as the training set. Then we use the prediction scores as covariates to prioritize RVAS results via IHW. We demonstrate the effectiveness of this framework through applications to RVASs in schizophrenia and autism spectrum disorder. We found sizeable improvements in the number of significant associations compared to traditional FDR approaches, and independent evidence supporting the relevance of the genes identified by our framework but not traditional FDR, demonstrating the potential of our framework to improve power of gene-based RVASs.
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Affiliation(s)
- Ying Ji
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN 37232, USA; (Y.J.); (R.C.); (Q.W.); (Q.W.)
- Vanderbilt Genetics Institute, Vanderbilt University, Nashville, TN 37203, USA
| | - Rui Chen
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN 37232, USA; (Y.J.); (R.C.); (Q.W.); (Q.W.)
- Vanderbilt Genetics Institute, Vanderbilt University, Nashville, TN 37203, USA
| | - Quan Wang
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN 37232, USA; (Y.J.); (R.C.); (Q.W.); (Q.W.)
- Vanderbilt Genetics Institute, Vanderbilt University, Nashville, TN 37203, USA
| | - Qiang Wei
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN 37232, USA; (Y.J.); (R.C.); (Q.W.); (Q.W.)
- Vanderbilt Genetics Institute, Vanderbilt University, Nashville, TN 37203, USA
| | - Ran Tao
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN 37232, USA; (Y.J.); (R.C.); (Q.W.); (Q.W.)
- Department of Biostatistics, Vanderbilt University, Nashville, TN 37203, USA
- Correspondence: (R.T.); (B.L.)
| | - Bingshan Li
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN 37232, USA; (Y.J.); (R.C.); (Q.W.); (Q.W.)
- Vanderbilt Genetics Institute, Vanderbilt University, Nashville, TN 37203, USA
- Correspondence: (R.T.); (B.L.)
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Carvajal-Oliveros A, Campusano JM. Studying the Contribution of Serotonin to Neurodevelopmental Disorders. Can This Fly? Front Behav Neurosci 2021; 14:601449. [PMID: 33510625 PMCID: PMC7835640 DOI: 10.3389/fnbeh.2020.601449] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 12/14/2020] [Indexed: 12/31/2022] Open
Abstract
Serotonin is a biogenic amine that acts as neurotransmitter in different brain regions and is involved in complex behaviors, such as aggression or mood regulation. Thus, this amine is found in defined circuits and activates specific receptors in different target regions. Serotonin actions depend on extracellular levels of this amine, which are regulated by its synthetic enzymes and the plasma membrane transporter, SERT. Serotonin acts also as a neurotrophic signal in ontogeny and in the mature brain, controlling cell proliferation, differentiation, neurogenesis, and neural plasticity. Interestingly, early alterations in serotonergic signaling have been linked to a diversity of neurodevelopmental disorders, including autism spectrum disorder (ASD), attention deficit/hyperactivity disorder (ADHD), or mental illnesses like schizophrenia or depression. It has been proposed that given the complex and numerous actions of serotonin, animal models could better serve to study the complexity of serotonin actions, while providing insights on how hindering serotonergic signaling could contribute to brain disorders. In this mini-review, it will be examined what the general properties of serotonin acting as a neurotransmitter in animals are, and furthermore, whether it is possible that Drosophila could be used to study the contribution of this amine to neurodevelopmental and mental disorders.
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Affiliation(s)
- Angel Carvajal-Oliveros
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Jorge M Campusano
- Laboratorio Neurogenética de la Conducta, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Centro Interdisciplinario de Neurociencia UC, Pontificia Universidad Católica de Chile, Santiago, Chile
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Bodnar B, DeGruttola A, Zhu Y, Lin Y, Zhang Y, Mo X, Hu W. Emerging role of NIK/IKK2-binding protein (NIBP)/trafficking protein particle complex 9 (TRAPPC9) in nervous system diseases. Transl Res 2020; 224:55-70. [PMID: 32434006 PMCID: PMC7442628 DOI: 10.1016/j.trsl.2020.05.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 05/02/2020] [Accepted: 05/05/2020] [Indexed: 02/05/2023]
Abstract
NFκB signaling and protein trafficking network play important roles in various biological and pathological processes. NIK-and-IKK2-binding protein (NIBP), also known as trafficking protein particle complex 9 (TRAPPC9), is a prototype member of a novel protein family, and has been shown to regulate both NFκB signaling pathway and protein transport/trafficking. NIBP is extensively expressed in the nervous system and plays an important role in regulating neurogenesis and neuronal differentiation. NIBP/TRAPPC9 mutations have been linked to an autosomal recessive intellectual disability syndrome, called NIBP Syndrome, which is characterized by nonsyndromic autosomal recessive intellectual disability along with other symptoms such as obesity, microcephaly, and facial dysmorphia. As more cases of NIBP Syndrome are identified, new light is being shed on the role of NIBP/TRAPPC9 in the central nervous system developments and diseases. NIBP is also involved in the enteric nervous system. This review will highlight the importance of NIBP/TRAPPC9 in central and enteric nervous system diseases, and the established possible mechanisms for developing a potential therapeutic.
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Affiliation(s)
- Brittany Bodnar
- Center for Metabolic Disease Research, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania; MD/PhD and Biomedical Sciences Graduate Program, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania
| | - Arianna DeGruttola
- Center for Metabolic Disease Research, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania; MD/PhD and Biomedical Sciences Graduate Program, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania
| | - Yuanjun Zhu
- Center for Metabolic Disease Research, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania; Department of Pathology and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania; Department of Molecular and Cellular Pharmacology, Peking University School of Pharmaceutical Sciences, Beijing, China
| | - Yuan Lin
- Center for Metabolic Disease Research, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania; Department of Pathology and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania
| | - Yonggang Zhang
- Center for Stem Cell Research and Application, Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu, China
| | - Xianming Mo
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, China
| | - Wenhui Hu
- Center for Metabolic Disease Research, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania; MD/PhD and Biomedical Sciences Graduate Program, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania; Department of Pathology and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania.
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Wong JKL, Gui H, Kwok M, Ng PW, Lui CHT, Baum L, Sham PC, Kwan P, Cherny SS. Rare variants and de novo variants in mesial temporal lobe epilepsy with hippocampal sclerosis. NEUROLOGY-GENETICS 2018; 4:e245. [PMID: 29904720 PMCID: PMC5999346 DOI: 10.1212/nxg.0000000000000245] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 04/13/2018] [Indexed: 12/03/2022]
Abstract
Objective We investigated the role of rare genetic variants and of de novo variants in the pathogenesis of mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS). Methods Whole-exome sequencing (WES) was performed in patients with MTLE-HS and their unaffected parents (trios). Genes or gene sets that were enriched with predicted damaging rare variants in the patients as compared to population controls were identified. Patients and their parents were compared to identify whether the variants were de novo or inherited. Results After quality control, WES data from 47 patients (26 female), including 23 complete trios, were available for analysis. Compared with population controls, significant enrichment of rare variants was observed in SEC24B. Integration of gene set data describing neuronal functions and psychiatric disorders showed enrichment signal on fragile X mental retardation protein (FMRP) targets. Twenty-one de novo variants were identified, with many known to cause neuropsychiatric disorders. The FMRP-targeted genes also carried more de novo variants. Inherited compound heterozygous and homozygous variants were identified. Conclusions The genetic architecture underlying MTHE-HS is complex. Multiple genes carrying de novo variants and rare variants among FMRP targets were identified, suggesting a pathogenic role. MTLE-HS and other neuropsychiatric disorders may have shared biology.
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Affiliation(s)
- John K L Wong
- Centre for Genomic Sciences and Department of Psychiatry (J.K.L.W., H.G., L.B., P.C.S., S.S.C.), Li Ka Shing Faculty of Medicine, The University of Hong Kong; Department of Medicine and Therapeutics (M.K., P.K.), The Chinese University of Hong Kong; Department of Medicine (P.W.N.), United Christian Hospital; Department of Medicine (C.H.T.L.), Queen Elizabeth Hospital, Hong Kong, China; Departments of Medicine and Neurology (P.K.), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Epidemiology and Preventive Medicine (S.S.C.) and Department of Anatomy and Anthropology (S.S.C.), Sackler Faculty of Medicine, Tel Aviv University, Israel; and The State Key Laboratory of Brain and Cognitive Sciences (P.C.S., S.S.C.)
| | - Hongsheng Gui
- Centre for Genomic Sciences and Department of Psychiatry (J.K.L.W., H.G., L.B., P.C.S., S.S.C.), Li Ka Shing Faculty of Medicine, The University of Hong Kong; Department of Medicine and Therapeutics (M.K., P.K.), The Chinese University of Hong Kong; Department of Medicine (P.W.N.), United Christian Hospital; Department of Medicine (C.H.T.L.), Queen Elizabeth Hospital, Hong Kong, China; Departments of Medicine and Neurology (P.K.), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Epidemiology and Preventive Medicine (S.S.C.) and Department of Anatomy and Anthropology (S.S.C.), Sackler Faculty of Medicine, Tel Aviv University, Israel; and The State Key Laboratory of Brain and Cognitive Sciences (P.C.S., S.S.C.)
| | - Maxwell Kwok
- Centre for Genomic Sciences and Department of Psychiatry (J.K.L.W., H.G., L.B., P.C.S., S.S.C.), Li Ka Shing Faculty of Medicine, The University of Hong Kong; Department of Medicine and Therapeutics (M.K., P.K.), The Chinese University of Hong Kong; Department of Medicine (P.W.N.), United Christian Hospital; Department of Medicine (C.H.T.L.), Queen Elizabeth Hospital, Hong Kong, China; Departments of Medicine and Neurology (P.K.), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Epidemiology and Preventive Medicine (S.S.C.) and Department of Anatomy and Anthropology (S.S.C.), Sackler Faculty of Medicine, Tel Aviv University, Israel; and The State Key Laboratory of Brain and Cognitive Sciences (P.C.S., S.S.C.)
| | - Ping Wing Ng
- Centre for Genomic Sciences and Department of Psychiatry (J.K.L.W., H.G., L.B., P.C.S., S.S.C.), Li Ka Shing Faculty of Medicine, The University of Hong Kong; Department of Medicine and Therapeutics (M.K., P.K.), The Chinese University of Hong Kong; Department of Medicine (P.W.N.), United Christian Hospital; Department of Medicine (C.H.T.L.), Queen Elizabeth Hospital, Hong Kong, China; Departments of Medicine and Neurology (P.K.), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Epidemiology and Preventive Medicine (S.S.C.) and Department of Anatomy and Anthropology (S.S.C.), Sackler Faculty of Medicine, Tel Aviv University, Israel; and The State Key Laboratory of Brain and Cognitive Sciences (P.C.S., S.S.C.)
| | - Colin H T Lui
- Centre for Genomic Sciences and Department of Psychiatry (J.K.L.W., H.G., L.B., P.C.S., S.S.C.), Li Ka Shing Faculty of Medicine, The University of Hong Kong; Department of Medicine and Therapeutics (M.K., P.K.), The Chinese University of Hong Kong; Department of Medicine (P.W.N.), United Christian Hospital; Department of Medicine (C.H.T.L.), Queen Elizabeth Hospital, Hong Kong, China; Departments of Medicine and Neurology (P.K.), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Epidemiology and Preventive Medicine (S.S.C.) and Department of Anatomy and Anthropology (S.S.C.), Sackler Faculty of Medicine, Tel Aviv University, Israel; and The State Key Laboratory of Brain and Cognitive Sciences (P.C.S., S.S.C.)
| | - Larry Baum
- Centre for Genomic Sciences and Department of Psychiatry (J.K.L.W., H.G., L.B., P.C.S., S.S.C.), Li Ka Shing Faculty of Medicine, The University of Hong Kong; Department of Medicine and Therapeutics (M.K., P.K.), The Chinese University of Hong Kong; Department of Medicine (P.W.N.), United Christian Hospital; Department of Medicine (C.H.T.L.), Queen Elizabeth Hospital, Hong Kong, China; Departments of Medicine and Neurology (P.K.), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Epidemiology and Preventive Medicine (S.S.C.) and Department of Anatomy and Anthropology (S.S.C.), Sackler Faculty of Medicine, Tel Aviv University, Israel; and The State Key Laboratory of Brain and Cognitive Sciences (P.C.S., S.S.C.)
| | - Pak Chung Sham
- Centre for Genomic Sciences and Department of Psychiatry (J.K.L.W., H.G., L.B., P.C.S., S.S.C.), Li Ka Shing Faculty of Medicine, The University of Hong Kong; Department of Medicine and Therapeutics (M.K., P.K.), The Chinese University of Hong Kong; Department of Medicine (P.W.N.), United Christian Hospital; Department of Medicine (C.H.T.L.), Queen Elizabeth Hospital, Hong Kong, China; Departments of Medicine and Neurology (P.K.), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Epidemiology and Preventive Medicine (S.S.C.) and Department of Anatomy and Anthropology (S.S.C.), Sackler Faculty of Medicine, Tel Aviv University, Israel; and The State Key Laboratory of Brain and Cognitive Sciences (P.C.S., S.S.C.)
| | - Patrick Kwan
- Centre for Genomic Sciences and Department of Psychiatry (J.K.L.W., H.G., L.B., P.C.S., S.S.C.), Li Ka Shing Faculty of Medicine, The University of Hong Kong; Department of Medicine and Therapeutics (M.K., P.K.), The Chinese University of Hong Kong; Department of Medicine (P.W.N.), United Christian Hospital; Department of Medicine (C.H.T.L.), Queen Elizabeth Hospital, Hong Kong, China; Departments of Medicine and Neurology (P.K.), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Epidemiology and Preventive Medicine (S.S.C.) and Department of Anatomy and Anthropology (S.S.C.), Sackler Faculty of Medicine, Tel Aviv University, Israel; and The State Key Laboratory of Brain and Cognitive Sciences (P.C.S., S.S.C.)
| | - Stacey S Cherny
- Centre for Genomic Sciences and Department of Psychiatry (J.K.L.W., H.G., L.B., P.C.S., S.S.C.), Li Ka Shing Faculty of Medicine, The University of Hong Kong; Department of Medicine and Therapeutics (M.K., P.K.), The Chinese University of Hong Kong; Department of Medicine (P.W.N.), United Christian Hospital; Department of Medicine (C.H.T.L.), Queen Elizabeth Hospital, Hong Kong, China; Departments of Medicine and Neurology (P.K.), The University of Melbourne, Royal Melbourne Hospital, Australia; Department of Epidemiology and Preventive Medicine (S.S.C.) and Department of Anatomy and Anthropology (S.S.C.), Sackler Faculty of Medicine, Tel Aviv University, Israel; and The State Key Laboratory of Brain and Cognitive Sciences (P.C.S., S.S.C.)
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Xiao X, Putatunda R, Zhang Y, Soni PV, Li F, Zhang T, Xin M, Luo JJ, Bethea JR, Cheng Y, Hu W. Lymphotoxin β receptor-mediated NFκB signaling promotes glial lineage differentiation and inhibits neuronal lineage differentiation in mouse brain neural stem/progenitor cells. J Neuroinflammation 2018; 15:49. [PMID: 29463313 PMCID: PMC5819232 DOI: 10.1186/s12974-018-1074-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 01/22/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Lymphotoxin (LT) is a lymphokine mainly expressed in lymphocytes. LTα binds one or two membrane-associated LTβ to form LTα2β1 or LTα1β2 heterotrimers. The predominant LTα1β2 binds to LTβ receptor (LTβR) primarily expressed in epithelial and stromal cells. Most studies on LTβR signaling have focused on the organization, development, and maintenance of lymphoid tissues. However, the roles of LTβR signaling in the nervous system, particularly in neurogenesis, remain unknown. Here, we investigated the role of LTβR-mediated NFκB signaling in regulating neural lineage differentiation. METHODS The C57BL/6J wild-type and GFAP-dnIκBα transgenic mice were used. Serum-free embryoid bodies were cultured from mouse embryonic stem cells and further induced into neural stem/progenitor cells (NSCs/NPCs). Primary neurospheres were cultured from embryonic and adult mouse brains followed by monolayer culture for amplification/passage. NFκB activation was determined by adenovirus-mediated NFκB-firefly-luciferase reporter assay and p65/RelB/p52 nuclear translocation assay. LTβR mRNA expression was evaluated by quantitative RT-PCR and LTβR protein expression was determined by immunohistochemistry and Western blot analysis. Multilabeled immunocytochemistry or immunohistochemistry followed by fluorescent confocal microscopy and quantitative analysis of neural lineage differentiation were performed. Graphing and statistical analysis were performed with GraphPad Prism software. RESULTS In cultured NSCs/NPCs, LTα1β2 stimulation induced an activation of classical and non-classical NFκB signaling. The expression of LTβR-like immunoreactivity in GFAP+/Sox2+ NSCs was identified in well-established neurogenic zones of adult mouse brain. Quantitative RT-PCR and Western blot analysis validated the expression of LTβR in cultured NSCs/NPCs and brain neurogenic regions. LTβR expression was significantly increased during neural induction. LTα1β2 stimulation in cultured NSCs/NPCs promoted astroglial and oligodendrocytic lineage differentiation, but inhibited neuronal lineage differentiation. Astroglial NFκB inactivation in GFAP-dnIκBα transgenic mice rescued LTβR-mediated abnormal phenotypes of cultured NSCs/NPCs. CONCLUSION This study provides the first evidence for the expression and function of LTβR signaling in NSCs/NPCs. Activation of LTβR signaling promotes glial lineage differentiation. Our results suggest that neurogenesis is regulated by the adaptive immunity and inflammatory responses.
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Affiliation(s)
- Xiao Xiao
- Department of Neurosurgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
- Center for Metabolic Disease Research, Department of Pathology and Laboratory Medicine, Temple University Lewis Katz School of Medicine, 3500 N Broad Street, Philadelphia, PA, 19140, USA
| | - Raj Putatunda
- Center for Metabolic Disease Research, Department of Pathology and Laboratory Medicine, Temple University Lewis Katz School of Medicine, 3500 N Broad Street, Philadelphia, PA, 19140, USA
| | - Yonggang Zhang
- Center for Metabolic Disease Research, Department of Pathology and Laboratory Medicine, Temple University Lewis Katz School of Medicine, 3500 N Broad Street, Philadelphia, PA, 19140, USA
| | - Priya V Soni
- Center for Metabolic Disease Research, Department of Pathology and Laboratory Medicine, Temple University Lewis Katz School of Medicine, 3500 N Broad Street, Philadelphia, PA, 19140, USA
| | - Fang Li
- Center for Metabolic Disease Research, Department of Pathology and Laboratory Medicine, Temple University Lewis Katz School of Medicine, 3500 N Broad Street, Philadelphia, PA, 19140, USA
| | - Ting Zhang
- Center for Metabolic Disease Research, Department of Pathology and Laboratory Medicine, Temple University Lewis Katz School of Medicine, 3500 N Broad Street, Philadelphia, PA, 19140, USA
| | - Mingyang Xin
- Center for Metabolic Disease Research, Department of Pathology and Laboratory Medicine, Temple University Lewis Katz School of Medicine, 3500 N Broad Street, Philadelphia, PA, 19140, USA
| | - Jin Jun Luo
- Department of Neurology, Temple University Lewis Katz School of Medicine, 3401 N Broad Street, Philadelphia, PA, USA
| | - John R Bethea
- Department of Biology, Drexel University, Philadelphia, PA, USA
| | - Yuan Cheng
- Department of Neurosurgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China.
| | - Wenhui Hu
- Center for Metabolic Disease Research, Department of Pathology and Laboratory Medicine, Temple University Lewis Katz School of Medicine, 3500 N Broad Street, Philadelphia, PA, 19140, USA.
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Arai Y, Taverna E. Neural Progenitor Cell Polarity and Cortical Development. Front Cell Neurosci 2017; 11:384. [PMID: 29259543 PMCID: PMC5723293 DOI: 10.3389/fncel.2017.00384] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 11/17/2017] [Indexed: 12/15/2022] Open
Abstract
Neurons populating the cerebral cortex are generated during embryonic development from neural stem and progenitor cells in a process called neurogenesis. Neural stem and progenitor cells are classified into several classes based on the different location of mitosis (apical or basal) and polarity features (bipolar, monopolar and non-polar). The polarized architecture of stem cells is linked to the asymmetric localization of proteins, mRNAs and organelles, such as the centrosome and the Golgi apparatus (GA). Polarity affects stem cell function and allows stem cells to integrate environmental cues from distinct niches in the developing cerebral cortex. The crucial role of polarity in neural stem and progenitor cells is highlighted by the fact that impairment of cell polarity is linked to neurodevelopmental disorders such as Down syndrome, Fragile X syndrome, autism spectrum disorders (ASD) and schizophrenia.
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Affiliation(s)
- Yoko Arai
- Centre for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS UMR 7241/INSERM U1050, PSL Research University, Paris, France
| | - Elena Taverna
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology (MPG), Leipzig, Germany
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Autism spectrum disorders and disease modeling using stem cells. Cell Tissue Res 2017; 371:153-160. [PMID: 28918504 DOI: 10.1007/s00441-017-2685-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 08/19/2017] [Indexed: 12/13/2022]
Abstract
Autism spectrum disorders (ASD) represent a variety of disorders characterized as complex lifelong neurodevelopment disabilities, which may affect the ability of communication and socialization, including typical comportments like repetitive and stereotyped behavior. Other comorbidities are usually present, such as echolalia, hypotonia, intellectual disability and difficulties in processing figured speech. Furthermore, some ASD individuals may present certain abilities, such as eidetic memory, outstanding musical or painting talents and special mathematical skills, among others. Considering the variability of the clinical symptoms, one autistic individual can be severely affected in communication while others can speak perfectly, sometimes having a vocabulary above average in early childhood. The same variability can be seen in other clinical symptoms, thus the "spectrum" can vary from severe to mild. Induced pluripotent stem cell technology has been used to model several neurological diseases, including syndromic and non-syndromic autism. We discuss how modeling the central nervous system cells in a dish may help to reach a better understanding of ASD pathology and variability, as well as personalize their treatment.
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Achuta VS, Grym H, Putkonen N, Louhivuori V, Kärkkäinen V, Koistinaho J, Roybon L, Castrén ML. Metabotropic glutamate receptor 5 responses dictate differentiation of neural progenitors to NMDA-responsive cells in fragile X syndrome. Dev Neurobiol 2016; 77:438-453. [PMID: 27411166 DOI: 10.1002/dneu.22419] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 06/14/2016] [Accepted: 07/12/2016] [Indexed: 01/04/2023]
Abstract
Disrupted metabotropic glutamate receptor 5 (mGluR5) signaling is implicated in many neuropsychiatric disorders, including autism spectrum disorder, found in fragile X syndrome (FXS). Here we report that intracellular calcium responses to the group I mGluR agonist (S)-3,5-dihydroxyphenylglycine (DHPG) are augmented, and calcium-dependent mGluR5-mediated mechanisms alter the differentiation of neural progenitors in neurospheres derived from human induced pluripotent FXS stem cells and the brains of mouse model of FXS. Treatment with the mGluR5 antagonist 2-methyl-6-(phenylethynyl)-pyridine (MPEP) prevents an abnormal clustering of DHPG-responsive cells that are responsive to activation of ionotropic receptors in mouse FXS neurospheres. MPEP also corrects morphological defects of differentiated cells and enhanced migration of neuron-like cells in mouse FXS neurospheres. Unlike in mouse neurospheres, MPEP increases the differentiation of DHPG-responsive radial glial cells as well as the subpopulation of cells responsive to both DHPG and activation of ionotropic receptors in human neurospheres. However, MPEP normalizes the FXS-specific increase in the differentiation of cells responsive only to N-methyl-d-aspartate (NMDA) present in human neurospheres. Exposure to MPEP prevents the accumulation of intermediate basal progenitors in embryonic FXS mouse brain suggesting that rescue effects of GluR5 antagonist are progenitor type-dependent and species-specific differences of basal progenitors may modify effects of MPEP on the cortical development. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 419-437, 2017.
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Affiliation(s)
- Venkat Swaroop Achuta
- Faculty of Medicine, Physiology, University of Helsinki, P.O. Box 63, Helsinki, FIN, 00014, Finland
| | - Heli Grym
- Faculty of Medicine, Physiology, University of Helsinki, P.O. Box 63, Helsinki, FIN, 00014, Finland
| | - Noora Putkonen
- Faculty of Medicine, Physiology, University of Helsinki, P.O. Box 63, Helsinki, FIN, 00014, Finland
| | - Verna Louhivuori
- Faculty of Medicine, Physiology, University of Helsinki, P.O. Box 63, Helsinki, FIN, 00014, Finland
| | - Virve Kärkkäinen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Jari Koistinaho
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Laurent Roybon
- Stem Cell Laboratory for CNS Disease Modeling, Department of Experimental Medical Science, Lund University, BMC A10, Sölvegatan 19, Lund, SE-221 84, Sweden
| | - Maija L Castrén
- Faculty of Medicine, Physiology, University of Helsinki, P.O. Box 63, Helsinki, FIN, 00014, Finland.,Autism Foundation, Kuortaneenkatu 7B, Helsinki, FI-00520, Finland
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I Believe I Can Fly!: Use of Drosophila as a Model Organism in Neuropsychopharmacology Research. Neuropsychopharmacology 2016; 41:1439-46. [PMID: 26576740 PMCID: PMC4832023 DOI: 10.1038/npp.2015.322] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 10/14/2015] [Accepted: 10/16/2015] [Indexed: 01/03/2023]
Abstract
Neuropsychiatric disorders are of complex etiology, often including a large genetic component. In order to help identify and study the molecular and physiological mechanisms that such genes participate in, numerous animal models have been established in a variety of species. Over the past decade, this has increasingly included the vinegar fly, Drosophila melanogaster. Here, we outline why we study an invertebrate organism in the context of neuropsychiatric disorders, and we discuss how we can gain insight from studies in Drosophila. We focus on a few disorders and findings to make the larger point that modeling these diseases in flies can have both mechanistic and predictive validity. Highlighting some translational examples, we underline the fact that their brains works more like ours than one would have anticipated.
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Weisz ED, Monyak RE, Jongens TA. Deciphering discord: How Drosophila research has enhanced our understanding of the importance of FMRP in different spatial and temporal contexts. Exp Neurol 2015; 274:14-24. [PMID: 26026973 DOI: 10.1016/j.expneurol.2015.05.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 05/18/2015] [Accepted: 05/23/2015] [Indexed: 01/06/2023]
Abstract
Fragile X Syndrome (FXS) is the most common heritable form of intellectual impairment as well as the leading monogenetic cause of autism. In addition to its canonical definition as a neurodevelopmental disease, recent findings in the clinic suggest that FXS is a systemic disorder that is characterized by a variety of heterogeneous phenotypes. Efforts to study FXS pathogenesis have been aided by the development and characterization of animal models of the disease. Research efforts in Drosophila melanogaster have revealed key insights into the mechanistic underpinnings of FXS. While much remains unknown, it is increasingly apparent that FXS involves a myriad of spatially and temporally specific alterations in cellular function. Consequently, the literature is filled with numerous discordant findings. Researchers and clinicians alike must be cognizant of this dissonance, as it will likely be important for the design of preclinical studies to assess the efficacy of therapeutic strategies to improve the lives of FXS patients.
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Affiliation(s)
- Eliana D Weisz
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States
| | - Rachel E Monyak
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States
| | - Thomas A Jongens
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States.
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11
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Halevy T, Czech C, Benvenisty N. Molecular mechanisms regulating the defects in fragile X syndrome neurons derived from human pluripotent stem cells. Stem Cell Reports 2015; 4:37-46. [PMID: 25483109 PMCID: PMC4297868 DOI: 10.1016/j.stemcr.2014.10.015] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 10/29/2014] [Accepted: 10/29/2014] [Indexed: 11/27/2022] Open
Abstract
Fragile X syndrome (FXS) is caused by the absence of the fragile X mental retardation protein (FMRP). We have previously generated FXS-induced pluripotent stem cells (iPSCs) from patients' fibroblasts. In this study, we aimed at unraveling the molecular phenotype of the disease. Our data revealed aberrant regulation of neural differentiation and axon guidance genes in FXS-derived neurons, which are regulated by the RE-1 silencing transcription factor (REST). Moreover, we found REST to be elevated in FXS-derived neurons. As FMRP is involved in the microRNA (miRNA) pathway, we employed miRNA-array analyses and uncovered several miRNAs dysregulated in FXS-derived neurons. We found hsa-mir-382 to be downregulated in FXS-derived neurons, and introduction of mimic-mir-382 into these neurons was sufficient to repress REST and upregulate its axon guidance target genes. Our data link FMRP and REST through the miRNA pathway and show a new aspect in the development of FXS.
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Affiliation(s)
- Tomer Halevy
- Azrieli Center for Stem Cells and Genetic Research, Department of Genetics, Institute of Life Sciences, The Hebrew University, Givat-Ram, Jerusalem 91904, Israel
| | - Christian Czech
- Roche Pharmaceutical Research & Early Development, Neuroscience, Roche Innovation Center, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Nissim Benvenisty
- Azrieli Center for Stem Cells and Genetic Research, Department of Genetics, Institute of Life Sciences, The Hebrew University, Givat-Ram, Jerusalem 91904, Israel.
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12
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Neale BM, Sklar P. Genetic analysis of schizophrenia and bipolar disorder reveals polygenicity but also suggests new directions for molecular interrogation. Curr Opin Neurobiol 2014; 30:131-8. [PMID: 25544106 DOI: 10.1016/j.conb.2014.12.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 11/25/2014] [Accepted: 12/01/2014] [Indexed: 12/12/2022]
Abstract
Over the last few years, genetics research has made significant strides in identifying many risk factors for schizophrenia and bipolar disorder. These risk factors include inherited common single nucleotide polymorphisms, copy number variants, and rare single nucleotide variants, as well as rare de novo variants. For all variants, the common theme has been that of polygenicity, meaning that many small genetic risk factors influence risk in the population and that no gene or variant on its own has been shown to be fully deterministic of schizophrenia or bipolar. When taken together, biological themes that have emerged including the importance of synaptic function and calcium signaling. This has implications for our understanding of the biological underpinnings of these diseases.
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Affiliation(s)
- Benjamin M Neale
- Analytical and Translational Genetics Unit and Psychiatric and Neurodevelopmental Genetics Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Stanley Center for Psychiatric Research and Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA, 02142, USA.
| | - Pamela Sklar
- Division of Psychiatric Genomics, Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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13
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Halevy T, Urbach A. Comparing ESC and iPSC-Based Models for Human Genetic Disorders. J Clin Med 2014; 3:1146-62. [PMID: 26237596 PMCID: PMC4470175 DOI: 10.3390/jcm3041146] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 09/29/2014] [Accepted: 09/30/2014] [Indexed: 12/19/2022] Open
Abstract
Traditionally, human disorders were studied using animal models or somatic cells taken from patients. Such studies enabled the analysis of the molecular mechanisms of numerous disorders, and led to the discovery of new treatments. Yet, these systems are limited or even irrelevant in modeling multiple genetic diseases. The isolation of human embryonic stem cells (ESCs) from diseased blastocysts, the derivation of induced pluripotent stem cells (iPSCs) from patients' somatic cells, and the new technologies for genome editing of pluripotent stem cells have opened a new window of opportunities in the field of disease modeling, and enabled studying diseases that couldn't be modeled in the past. Importantly, despite the high similarity between ESCs and iPSCs, there are several fundamental differences between these cells, which have important implications regarding disease modeling. In this review we compare ESC-based models to iPSC-based models, and highlight the advantages and disadvantages of each system. We further suggest a roadmap for how to choose the optimal strategy to model each specific disorder.
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Affiliation(s)
- Tomer Halevy
- Stem Cell Unit, Department of Genetics, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
| | - Achia Urbach
- Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 5290002, Israel.
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14
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Li Y, Zhao X. Concise review: Fragile X proteins in stem cell maintenance and differentiation. Stem Cells 2014; 32:1724-33. [PMID: 24648324 PMCID: PMC4255947 DOI: 10.1002/stem.1698] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Revised: 02/18/2014] [Accepted: 03/01/2014] [Indexed: 12/15/2022]
Abstract
Fragile X syndrome (FXS), the most common genetic form of autism spectrum disorder, is caused by deficiency of the fragile X mental retardation protein (FMRP). Despite extensive research and scientific progress, understanding how FMRP regulates brain development and function remains a major challenge. FMRP is a neuronal RNA-binding protein that binds about a third of messenger RNAs in the brain and controls their translation, stability, and cellular localization. The absence of FMRP results in increased protein synthesis, leading to enhanced signaling in a number of intracellular pathways, including the mTOR, mGLuR5, ERK, Gsk3β, PI3K, and insulin pathways. Until recently, FXS was largely considered a deficit of mature neurons; however, a number of new studies have shown that FMRP may also play important roles in stem cells, among them neural stem cells, germline stem cells, and pluripotent stem cells. In this review, we will cover these newly discovered functions of FMRP, as well as the other two fragile X-related proteins, in stem cells. We will also discuss the literature on the use of stem cells, particularly neural stem cells and induced pluripotent stem cells, as model systems for studying the functions of FMRP in neuronal development.
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Affiliation(s)
- Yue Li
- Waisman Center and Department of Neuroscience, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
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15
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Tissue plasminogen activator contributes to alterations of neuronal migration and activity-dependent responses in fragile X mice. J Neurosci 2014; 34:1916-23. [PMID: 24478370 DOI: 10.1523/jneurosci.3753-13.2014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common inherited neurodevelopmental disorder with intellectual disability. Here, we show that the expression of tissue plasminogen activator (tPA) is increased in glial cells differentiated from neural progenitors of Fmr1 knock-out mice, a mouse model for FXS, and that tPA is involved in the altered migration and differentiation of these progenitors lacking FMR1 protein (FMRP). When tPA function is blocked with an antibody, enhanced migration of doublecortin-immunoreactive neurons in 1 d differentiated FMRP-deficient neurospheres is normalized. In time-lapse imaging, blocking the tPA function promotes early glial differentiation and reduces the velocity of nuclear movement of FMRP-deficient radial glia. In addition, we show that enhanced intracellular Ca(2+) responses to depolarization with potassium are prevented by the treatment with the tPA-neutralizing antibody in FMRP-deficient cells during early neural progenitor differentiation. Alterations of the tPA expression in the embryonic, postnatal, and adult brain of Fmr1 knock-out mice suggest an important role for tPA in the abnormal neuronal differentiation and plasticity in FXS. Altogether, the results indicate that tPA may prove to be an interesting potential target for pharmacological intervention in FXS.
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16
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Purcell SM, Moran JL, Fromer M, Ruderfer D, Solovieff N, Roussos P, O’Dushlaine C, Chambert K, Bergen SE, Kähler A, Duncan L, Stahl E, Genovese G, Fernández E, Collins MO, Komiyama NH, Choudhary JS, Magnusson PKE, Banks E, Shakir K, Garimella K, Fennell T, de Pristo M, Grant SG, Haggarty S, Gabriel S, Scolnick EM, Lander ES, Hultman C, Sullivan PF, McCarroll SA, Sklar P. A polygenic burden of rare disruptive mutations in schizophrenia. Nature 2014; 506:185-90. [PMID: 24463508 PMCID: PMC4136494 DOI: 10.1038/nature12975] [Citation(s) in RCA: 1020] [Impact Index Per Article: 102.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 12/24/2013] [Indexed: 12/11/2022]
Abstract
Schizophrenia is a common disease with a complex aetiology, probably involving multiple and heterogeneous genetic factors. Here, by analysing the exome sequences of 2,536 schizophrenia cases and 2,543 controls, we demonstrate a polygenic burden primarily arising from rare (less than 1 in 10,000), disruptive mutations distributed across many genes. Particularly enriched gene sets include the voltage-gated calcium ion channel and the signalling complex formed by the activity-regulated cytoskeleton-associated scaffold protein (ARC) of the postsynaptic density, sets previously implicated by genome-wide association and copy-number variation studies. Similar to reports in autism, targets of the fragile X mental retardation protein (FMRP, product of FMR1) are enriched for case mutations. No individual gene-based test achieves significance after correction for multiple testing and we do not detect any alleles of moderately low frequency (approximately 0.5 to 1 per cent) and moderately large effect. Taken together, these data suggest that population-based exome sequencing can discover risk alleles and complements established gene-mapping paradigms in neuropsychiatric disease.
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Affiliation(s)
- Shaun M. Purcell
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
- Division of Psychiatric Genomics in the Department of Psychiatry, and Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Analytic and Translational Genetics Unit, Psychiatric and Neurodevelopmental Genetics Unit, Massachusetts General Hospital, Boston, MA, 02114, USA
- Medical & Population Genetics Program, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
| | - Jennifer L. Moran
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
| | - Menachem Fromer
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
- Division of Psychiatric Genomics in the Department of Psychiatry, and Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Analytic and Translational Genetics Unit, Psychiatric and Neurodevelopmental Genetics Unit, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Douglas Ruderfer
- Division of Psychiatric Genomics in the Department of Psychiatry, and Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Nadia Solovieff
- Analytic and Translational Genetics Unit, Psychiatric and Neurodevelopmental Genetics Unit, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Panos Roussos
- Division of Psychiatric Genomics in the Department of Psychiatry, and Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Colm O’Dushlaine
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
| | - Kimberly Chambert
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
| | - Sarah E. Bergen
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
- Department of Medical Epidemiology and Biostatisics, Karolinska Institutet, Stockholm, SE-171 77, Sweden
| | - Anna Kähler
- Department of Medical Epidemiology and Biostatisics, Karolinska Institutet, Stockholm, SE-171 77, Sweden
| | - Laramie Duncan
- Analytic and Translational Genetics Unit, Psychiatric and Neurodevelopmental Genetics Unit, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Eli Stahl
- Division of Psychiatric Genomics in the Department of Psychiatry, and Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Giulio Genovese
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
| | - Esperanza Fernández
- Center for Human Genetics, KU Leuven, 3000 Leuven, Belgium; VIB Center for Biology of Disease, 3000 Leuven, Belgium
| | - Mark O Collins
- Proteomic Mass Spectrometry, The Wellcome Trust Sanger Institute, Cambridge, UK
| | - Noboru H. Komiyama
- Proteomic Mass Spectrometry, The Wellcome Trust Sanger Institute, Cambridge, UK
| | - Jyoti S. Choudhary
- Proteomic Mass Spectrometry, The Wellcome Trust Sanger Institute, Cambridge, UK
| | - Patrik K. E. Magnusson
- Department of Medical Epidemiology and Biostatisics, Karolinska Institutet, Stockholm, SE-171 77, Sweden
| | - Eric Banks
- Medical & Population Genetics Program, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
| | - Khalid Shakir
- Medical & Population Genetics Program, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
| | - Kiran Garimella
- Medical & Population Genetics Program, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
| | - Tim Fennell
- Medical & Population Genetics Program, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
| | - Mark de Pristo
- Medical & Population Genetics Program, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
| | - Seth G.N. Grant
- Genes to Cognition Programme, Centre for Clinical Brain Sciences and Centre for Neuroregeneration, The University of Edinburgh, Edinburgh, UK
| | - Stephen Haggarty
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
- Analytic and Translational Genetics Unit, Psychiatric and Neurodevelopmental Genetics Unit, Massachusetts General Hospital, Boston, MA, 02114, USA
- Department of Neurology, Harvard Medical School, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Stacey Gabriel
- Medical & Population Genetics Program, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
| | - Edward M. Scolnick
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
| | - Eric S. Lander
- Medical & Population Genetics Program, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
| | - Christina Hultman
- Department of Medical Epidemiology and Biostatisics, Karolinska Institutet, Stockholm, SE-171 77, Sweden
| | - Patrick F. Sullivan
- Department of Genetics, University of North Carolina, CB# 7264, Chapel Hill, NC, 27599-7264, USA
| | - Steven A. McCarroll
- Stanley Center for Psychiatric Research, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
- Medical & Population Genetics Program, Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
- Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
| | - Pamela Sklar
- Division of Psychiatric Genomics in the Department of Psychiatry, and Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
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17
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Li Y, Tang W, Zhang LR, Zhang CY. FMRP regulates miR196a-mediated repression of HOXB8 via interaction with the AGO2 MID domain. MOLECULAR BIOSYSTEMS 2014; 10:1757-64. [DOI: 10.1039/c4mb00066h] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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18
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Steinberg J, Webber C. The roles of FMRP-regulated genes in autism spectrum disorder: single- and multiple-hit genetic etiologies. Am J Hum Genet 2013; 93:825-39. [PMID: 24207117 DOI: 10.1016/j.ajhg.2013.09.013] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 09/21/2013] [Accepted: 09/26/2013] [Indexed: 11/26/2022] Open
Abstract
Autism spectrum disorder (ASD) is a highly heritable complex neurodevelopmental condition characterized by impairments in social interaction and communication and restricted and repetitive behaviors. Although roles for both de novo and familial genetic variation have been documented, the underlying disease mechanisms remain poorly elucidated. In this study, we defined and explored distinct etiologies of genetic variants that affect genes regulated by Fragile-X mental retardation protein (FMRP), thought to play a key role in neuroplasticity and neuronal translation, in ASD-affected individuals. In particular, we developed the Trend test, a pathway-association test that is able to robustly detect multiple-hit etiologies and is more powerful than existing approaches. Exploiting detailed spatiotemporal maps of gene expression within the human brain, we identified four discrete FMRP-target subpopulations that exhibit distinct functional biases and contribute to ASD via different types of genetic variation. We also demonstrated that FMRP target genes are more likely than other genes with similar expression patterns to contribute to disease. We developed the hypothesis that FMRP targets contribute to ASD via two distinct etiologies: (1) ultra-rare and highly penetrant single disruptions of embryonically upregulated FMRP targets ("single-hit etiology") or (2) the combination of multiple less penetrant disruptions of nonembryonic, synaptic FMRP targets ("multiple-hit etiology"). The Trend test provides rigorous support for a multiple-hit genetic etiology in a subset of autism cases and is easily extendible to combining information from multiple types of genetic variation (i.e., copy-number and exome variants), increasing its value to next-generation sequencing approaches.
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19
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Friedman SH, Dani N, Rushton E, Broadie K. Fragile X mental retardation protein regulates trans-synaptic signaling in Drosophila. Dis Model Mech 2013; 6:1400-13. [PMID: 24046358 PMCID: PMC3820263 DOI: 10.1242/dmm.012229] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Fragile X syndrome (FXS), the most common inherited determinant of intellectual disability and autism spectrum disorders, is caused by loss of the fragile X mental retardation 1 (FMR1) gene product (FMRP), an mRNA-binding translational repressor. A number of conserved FMRP targets have been identified in the well-characterized Drosophila FXS disease model, but FMRP is highly pleiotropic in function and the full spectrum of FMRP targets has yet to be revealed. In this study, screens for upregulated neural proteins in Drosophila fmr1 (dfmr1) null mutants reveal strong elevation of two synaptic heparan sulfate proteoglycans (HSPGs): GPI-anchored glypican Dally-like protein (Dlp) and transmembrane Syndecan (Sdc). Our recent work has shown that Dlp and Sdc act as co-receptors regulating extracellular ligands upstream of intracellular signal transduction in multiple trans-synaptic pathways that drive synaptogenesis. Consistently, dfmr1 null synapses exhibit altered WNT signaling, with changes in both Wingless (Wg) ligand abundance and downstream Frizzled-2 (Fz2) receptor C-terminal nuclear import. Similarly, a parallel anterograde signaling ligand, Jelly belly (Jeb), and downstream ERK phosphorylation (dpERK) are depressed at dfmr1 null synapses. In contrast, the retrograde BMP ligand Glass bottom boat (Gbb) and downstream signaling via phosphorylation of the transcription factor MAD (pMAD) seem not to be affected. To determine whether HSPG upregulation is causative for synaptogenic defects, HSPGs were genetically reduced to control levels in the dfmr1 null background. HSPG correction restored both (1) Wg and Jeb trans-synaptic signaling, and (2) synaptic architecture and transmission strength back to wild-type levels. Taken together, these data suggest that FMRP negatively regulates HSPG co-receptors controlling trans-synaptic signaling during synaptogenesis, and that loss of this regulation causes synaptic structure and function defects characterizing the FXS disease state.
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Affiliation(s)
- Samuel H Friedman
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37212, USA
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20
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Cook D, Nuro E, Murai KK. Increasing our understanding of human cognition through the study of Fragile X Syndrome. Dev Neurobiol 2013; 74:147-77. [PMID: 23723176 PMCID: PMC4216185 DOI: 10.1002/dneu.22096] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 05/17/2013] [Indexed: 12/16/2022]
Abstract
Fragile X Syndrome (FXS) is considered the most common form of inherited intellectual disability. It is caused by reductions in the expression level or function of a single protein, the Fragile X Mental Retardation Protein (FMRP), a translational regulator which binds to approximately 4% of brain messenger RNAs. Accumulating evidence suggests that FXS is a complex disorder of cognition, involving interactions between genetic and environmental influences, leading to difficulties in acquiring key life skills including motor skills, language, and proper social behaviors. Since many FXS patients also present with one or more features of autism spectrum disorders (ASDs), insights gained from studying the monogenic basis of FXS could pave the way to a greater understanding of underlying features of multigenic ASDs. Here we present an overview of the FXS and FMRP field with the goal of demonstrating how loss of a single protein involved in translational control affects multiple stages of brain development and leads to debilitating consequences on human cognition. We also focus on studies which have rescued or improved FXS symptoms in mice using genetic or therapeutic approaches to reduce protein expression. We end with a brief description of how deficits in translational control are implicated in FXS and certain cases of ASDs, with many recent studies demonstrating that ASDs are likely caused by increases or decreases in the levels of certain key synaptic proteins. The study of FXS and its underlying single genetic cause offers an invaluable opportunity to study how a single gene influences brain development and behavior.
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Affiliation(s)
- Denise Cook
- Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada
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21
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Castrén ML, Castrén E. BDNF in fragile X syndrome. Neuropharmacology 2013; 76 Pt C:729-36. [PMID: 23727436 DOI: 10.1016/j.neuropharm.2013.05.018] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 05/07/2013] [Accepted: 05/08/2013] [Indexed: 12/12/2022]
Abstract
Fragile X syndrome (FXS) is a monogenic disorder that is caused by the absence of FMR1 protein (FMRP). FXS serves as an excellent model disorder for studies investigating disturbed molecular mechanisms and synapse function underlying cognitive impairment, autism, and behavioral disturbance. Abnormalities in dendritic spines and synaptic transmission in the brain of FXS individuals and mouse models for FXS indicate perturbations in the development, maintenance, and plasticity of neuronal network connectivity. However, numerous alterations are found during the early development in FXS, including abnormal differentiation of neural progenitors and impaired migration of newly born neurons. Several aspects of FMRP function are modulated by brain-derived neurotrophic factor (BDNF) signaling. Here, we review the evidence of the role for BDNF in the developing and adult FXS brain. This article is part of the Special Issue entitled 'BDNF Regulation of Synaptic Structure, Function, and Plasticity'.
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Affiliation(s)
- Maija L Castrén
- Institute of Biomedicine/Physiology, University of Helsinki, P.O. Box 63, FIN-00014 Helsinki, Finland; Rinnekoti Foundation, Rinnekodintie 10, FIN-02980 Espoo, Finland.
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22
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Lewitus E, Kalinka AT. Neocortical development as an evolutionary platform for intragenomic conflict. Front Neuroanat 2013; 7:2. [PMID: 23576960 PMCID: PMC3620502 DOI: 10.3389/fnana.2013.00002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 03/18/2013] [Indexed: 12/21/2022] Open
Abstract
Embryonic development in mammals has evolved a platform for genomic conflict between mothers and embryos and, by extension, between maternal and paternal genomes. The evolutionary interests of the mother and embryo may be maximized through the promotion of sex-chromosome genes and imprinted alleles, resulting in the rapid evolution of postzygotic phenotypes preferential to either the maternal or paternal genome. In eutherian mammals, extraordinary in utero maternal investment in the brain, and neocortex especially, suggests that convergent evolution of an expanded mammalian neocortex along divergent lineages may be explained, in part, by parent-of-origin-linked gene expression arising from parent-offspring conflict. The influence of this conflict on neocortical development and evolution, however, has not been investigated at the genomic level. In this hypothesis and theory article, we provide preliminary evidence for positive selection in humans in the regions of two platforms of intragenomic conflict—chromosomes 15q11-q13 and X—and explore the potential relevance of cis-regulated imprinted domains to neocortical expansion in mammalian evolution. We present the hypothesis that maternal- and paternal-specific pressures on the developing neocortex compete intragenomically to influence neocortical expansion in mammalian evolution.
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Affiliation(s)
- Eric Lewitus
- Max Planck Institute of Molecular Cell Biology and Genetics Dresden, Germany
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23
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Neurobehavioural evidence for the involvement of the FMR1 gene in female carriers of fragile X syndrome. Neurosci Biobehav Rev 2013; 37:522-47. [DOI: 10.1016/j.neubiorev.2013.01.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Revised: 12/11/2012] [Accepted: 01/06/2013] [Indexed: 12/19/2022]
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24
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Bagni C, Tassone F, Neri G, Hagerman R. Fragile X syndrome: causes, diagnosis, mechanisms, and therapeutics. J Clin Invest 2012. [PMID: 23202739 DOI: 10.1172/jci63141] [Citation(s) in RCA: 224] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Fragile X syndrome (FXS) is the most frequent form of inherited intellectual disability and is also linked to other neurologic and psychiatric disorders. FXS is caused by a triplet expansion that inhibits expression of the FMR1 gene; the gene product, FMRP, regulates mRNA metabolism in the brain and thus controls the expression of key molecules involved in receptor signaling and spine morphology. While there is no definitive cure for FXS, the understanding of FMRP function has paved the way for rational treatment designs that could potentially reverse many of the neurobiological changes observed in FXS. Additionally, behavioral, pharmacological, and cognitive interventions can raise the quality of life for both patients and their families.
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Affiliation(s)
- Claudia Bagni
- Katholieke Universiteit Leuven, Center for Human Genetics, Leuven, Belgium.
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Drosophila Rbp6 is an orthologue of vertebrate Msi-1 and Msi-2, but does not function redundantly with dMsi to regulate germline stem cell behaviour. PLoS One 2012; 7:e49810. [PMID: 23209605 PMCID: PMC3507872 DOI: 10.1371/journal.pone.0049810] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 10/17/2012] [Indexed: 01/29/2023] Open
Abstract
The vertebrate RNA-binding proteins, Musashi-1 (Msi-1) and Musashi-2 (Msi-2) are expressed in multiple stem cell populations. A role for Musashi proteins in preventing stem cell differentiation has been suggested from genetic analysis of the Drosophila family member, dMsi, and both vertebrate Msi proteins function co-operatively to regulate neural stem cell behaviour. Here we have identified a second Drosophila Msi family member, Rbp6, which shares more amino acid identity with vertebrate Msi-1 and Msi-2 than dMsi. We generated an antibody that detects most Rbp6 splice isoforms and show that Rbp6 is expressed in multiple tissues throughout development. However, Rbp6 deletion mutants generated in this study are viable and fertile, and show only minor defects. We used Drosophila spermatogonial germline stem cells (GSC’s) as a model to test whether Drosophila Msi proteins function redundantly to regulate stem cell behaviour. However, like vertebrate Msi-1 and Msi-2, Rbp6 and Msi do not appear to be co-expressed in spermatogenic GSC’s and do not function co-operatively in the regulation of GSC maintenance. Thus while two Msi family members are present in Drosophila, the function of the family members have diverged.
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Jeon SJ, Han SH, Yang SI, Choi JW, Kwon KJ, Park SH, Kim HY, Cheong JH, Ryu JH, Ko KH, Wells DG, Shin CY. Positive feedback regulation of Akt-FMRP pathway protects neurons from cell death. J Neurochem 2012; 123:226-38. [DOI: 10.1111/j.1471-4159.2012.07886.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Liu W, Jiang F, Bi X, Zhang YQ. Drosophila FMRP participates in the DNA damage response by regulating G2/M cell cycle checkpoint and apoptosis. Hum Mol Genet 2012; 21:4655-68. [PMID: 22843500 DOI: 10.1093/hmg/dds307] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Fragile X syndrome, the most common form of inherited mental retardation, is caused by the loss of the fragile X mental retardation protein (FMRP). FMRP is a ubiquitously expressed, multi-domain RNA-binding protein, but its in vivo function remains poorly understood. Recent studies have shown that FMRP participates in cell cycle control during development. Here, we used Drosophila mutants to test if FMRP plays a role in DNA damage response under genotoxic stress. We found significantly fewer dfmr1 mutants survived to adulthood than wild-types following irradiation or exposure to chemical mutagens, demonstrating that the loss of drosophila FMRP (dFMRP) results in hypersensitivity to genotoxic stress. Genotoxic stress significantly reduced mitotic cells in wild-type brains, indicating the activation of a DNA damage-induced G2/M checkpoint, while mitosis was only moderately suppressed in dfmr1 mutants. Elevated expression of cyclin B, a protein critical for the G2 to M transition, was observed in the larval brains of dfmr1 mutants. CycB mRNA transcripts were enriched in the dFMRP-containing complex, suggesting that dFMRP regulates DNA damage-induced G2/M checkpoint by repressing CycB mRNA translation. Reducing CycB dose by half in dfmr1 mutants rescued the defective G2/M checkpoint and reversed hypersensitivity to genotoxic stress. In addition, dfmr1 mutants exhibited more DNA breaks and elevated p53-dependent apoptosis following irradiation. Moreover, a loss-of-heterozygosity assay showed decreased irradiation-induced genome stability in dfmr1 mutants. Thus, dFMRP maintains genome stability under genotoxic stress and regulates the G2/M DNA damage checkpoint by suppressing CycB expression.
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Affiliation(s)
- Wei Liu
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
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28
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Abstract
Both embryonic and adult neurogenesis involves the self-renewal/proliferation, survival, migration and lineage differentiation of neural stem/progenitor cells. Such dynamic process is tightly regulated by intrinsic and extrinsic factors and complex signaling pathways. Misregulated neurogenesis contributes much to a large range of neurodevelopmental defects and neurodegenerative diseases. The signaling of NFκB regulates many genes important in inflammation, immunity, cell survival and neural plasticity. During neurogenesis, NFκB signaling mediates the effect of numerous niche factors such as cytokines, chemokines, growth factors, extracellular matrix molecules, but also crosstalks with other signaling pathways such as Notch, Shh, Wnt/β-catenin. This review summarizes current progress on the NFκB signaling in all aspects of neurogenesis, focusing on the novel role of NFκB signaling in initiating early neural differentiation of neural stem cells and embryonic stem cells.
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Affiliation(s)
- Yonggang Zhang
- Department of Neuroscience, Temple University School of Medicine, Philadelphia, PA 19140, USA
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29
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Reich J, Papoulas O. Caprin controls follicle stem cell fate in the Drosophila ovary. PLoS One 2012; 7:e35365. [PMID: 22493746 PMCID: PMC3320888 DOI: 10.1371/journal.pone.0035365] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 03/14/2012] [Indexed: 12/25/2022] Open
Abstract
Adult stem cells must balance self-renewal and differentiation for tissue homeostasis. The Drosophila ovary has provided a wealth of information about the extrinsic niche signals and intrinsic molecular processes required to ensure appropriate germline stem cell renewal and differentiation. The factors controlling behavior of the more recently identified follicle stem cells of the ovary are less well-understood but equally important for fertility. Here we report that translational regulators play a critical role in controlling these cells. Specifically, the translational regulator Caprin (Capr) is required in the follicle stem cell lineage to ensure maintenance of this stem cell population and proper encapsulation of developing germ cells by follicle stem cell progeny. In addition, reduction of one copy of the gene fmr1, encoding the translational regulator Fragile X Mental Retardation Protein, exacerbates the Capr encapsulation phenotype, suggesting Capr and fmr1 are regulating a common process. Caprin was previously characterized in vertebrates as Cytoplasmic Activation/Proliferation-Associated Protein. Significantly, we find that loss of Caprin alters the dynamics of the cell cycle, and we present evidence that misregulation of CycB contributes to the disruption in behavior of follicle stem cell progeny. Our findings support the idea that translational regulators may provide a conserved mechanism for oversight of developmentally critical cell cycles such as those in stem cell populations.
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Affiliation(s)
- John Reich
- The Section of Molecular Cell and Developmental Biology and the Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, United States of America
| | - Ophelia Papoulas
- The Section of Molecular Cell and Developmental Biology and the Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, United States of America
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Callan MA, Clements N, Ahrendt N, Zarnescu DC. Fragile X Protein is required for inhibition of insulin signaling and regulates glial-dependent neuroblast reactivation in the developing brain. Brain Res 2012; 1462:151-61. [PMID: 22513101 DOI: 10.1016/j.brainres.2012.03.042] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 03/16/2012] [Accepted: 03/17/2012] [Indexed: 11/16/2022]
Abstract
Fragile X syndrome (FXS) is the most common form of inherited mental disability and known cause of autism. It is caused by loss of function for the RNA binding protein FMRP, which has been demonstrated to regulate several aspects of RNA metabolism including transport, stability and translation at synapses. Recently, FMRP has been implicated in neural stem cell proliferation and differentiation both in cultured neurospheres as well as in vivo mouse and fly models of FXS. We have previously shown that FMRP deficient Drosophila neuroblasts upregulate Cyclin E, prematurely exit quiescence, and overproliferate to generate on average 16% more neurons. Here we further investigate FMRP's role during early development using the Drosophila larval brain as a model. Using tissue specific RNAi we find that FMRP is required sequentially, first in neuroblasts and then in glia, to regulate exit from quiescence as measured by Cyclin E expression in the brain. Furthermore, we tested the hypothesis that FMRP controls brain development by regulating the insulin signaling pathway, which has been recently shown to regulate neuroblast exit from quiescence. Our data indicate that phosphoAkt, a readout of insulin signaling, is upregulated in dFmr1 brains at the time when FMRP is required in glia for neuroblast reactivation. In addition, dFmr1 interacts genetically with dFoxO, a transcriptional regulator of insulin signaling. Our results provide the first evidence that FMRP is required in vivo, in glia for neuroblast reactivation and suggest that it may do so by regulating the output of the insulin signaling pathway. This article is part of a Special Issue entitled: RNA-Binding Proteins.
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Affiliation(s)
- Matthew A Callan
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA
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Winograd C, Ceman S. Fragile X family members have important and non-overlapping functions. Biomol Concepts 2011; 2:343-52. [DOI: 10.1515/bmc.2011.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 06/29/2011] [Indexed: 01/15/2023] Open
Abstract
AbstractThe fragile X family of genes encodes a small family of RNA binding proteins including FMRP, FXR1P and FXR2P that were identified in the 1990s. All three members are encoded by 17 exons and show alternative splicing at the 3′ ends of their respective transcripts. They share significant homology in the protein functional domains, including the Tudor domains, the nuclear localization sequence, a protein-protein interaction domain, the KH1 and KH2 domains and the nuclear export sequence. Fragile X family members are found throughout the animal kingdom, although all three members are not consistently present in species outside of mammals: only two family members are present in the avian species examined, Gallus gallus and Taeniopygia guttata, and in the frog Xenopus tropicalis. Although present in many tissues, the functions of the fragile X family members differ, which are particularly evident in knockout studies performed in animals. The fragile X family members play roles in normal neuronal function and in the case of FXR1, in muscle function.
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Affiliation(s)
- Claudia Winograd
- 2Neuroscience Program and College of Medicine, University of Illinois, 601 S. Goodwin Avenue, Urbana–Champaign, IL 61801, USA
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Davidovic L, Navratil V, Bonaccorso CM, Catania MV, Bardoni B, Dumas ME. A metabolomic and systems biology perspective on the brain of the fragile X syndrome mouse model. Genome Res 2011; 21:2190-202. [PMID: 21900387 DOI: 10.1101/gr.116764.110] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Fragile X syndrome (FXS) is the first cause of inherited intellectual disability, due to the silencing of the X-linked Fragile X Mental Retardation 1 gene encoding the RNA-binding protein FMRP. While extensive studies have focused on the cellular and molecular basis of FXS, neither human Fragile X patients nor the mouse model of FXS--the Fmr1-null mouse--have been profiled systematically at the metabolic and neurochemical level to provide a complementary perspective on the current, yet scattered, knowledge of FXS. Using proton high-resolution magic angle spinning nuclear magnetic resonance ((1)H HR-MAS NMR)-based metabolic profiling, we have identified a metabolic signature and biomarkers associated with FXS in various brain regions of Fmr1-deficient mice. Our study highlights for the first time that Fmr1 gene inactivation has profound, albeit coordinated consequences in brain metabolism leading to alterations in: (1) neurotransmitter levels, (2) osmoregulation, (3) energy metabolism, and (4) oxidative stress response. To functionally connect Fmr1-deficiency to its metabolic biomarkers, we derived a functional interaction network based on the existing knowledge (literature and databases) and show that the FXS metabolic response is initiated by distinct mRNA targets and proteins interacting with FMRP, and then relayed by numerous regulatory proteins. This novel "integrated metabolome and interactome mapping" (iMIM) approach advantageously unifies novel metabolic findings with previously unrelated knowledge and highlights the contribution of novel cellular pathways to the pathophysiology of FXS. These metabolomic and integrative systems biology strategies will contribute to the development of potential drug targets and novel therapeutic interventions, which will eventually benefit FXS patients.
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Affiliation(s)
- Laetitia Davidovic
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR 6097, 06560 Valbonne, France.
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