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Miyairi Y, Ohkawara B, Sato A, Sawada R, Ishii H, Tomita H, Inoue T, Nakashima H, Ito M, Masuda A, Hosono Y, Imagama S, Ohno K. A class of chemical compounds enhances clustering of muscle nicotinic acetylcholine receptor in cultured myogenic cells. Biochem Biophys Res Commun 2024; 731:150400. [PMID: 39024975 DOI: 10.1016/j.bbrc.2024.150400] [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: 05/07/2024] [Revised: 06/25/2024] [Accepted: 07/12/2024] [Indexed: 07/20/2024]
Abstract
Neuromuscular signal transmission is affected in various diseases including myasthenia gravis, congenital myasthenic syndromes, and sarcopenia. We used an ATF2-luciferase system to monitor the phosphorylation of MuSK in HEK293 cells introduced with MUSK and LRP4 cDNAs to find novel chemical compounds that enhanced agrin-mediated acetylcholine receptor (AChR) clustering. Four compounds with similar chemical structures carrying benzene rings and heterocyclic rings increased the luciferase activities 8- to 30-folds, and two of them showed continuously graded dose dependence. The effects were higher than that of disulfiram, a clinically available aldehyde dehydrogenase inhibitor, which we identified to be the most competent preapproved drug to enhance ATF2-luciferase activity in the same assay system. In C2C12 myotubes, all the compounds increased the area, intensity, length, and number of AChR clusters. Three of the four compounds increased the phosphorylation of MuSK, but not of Dok7, JNK. ERK, or p38. Monitoring cell toxicity using the neurite elongation of NSC34 neuronal cells as a surrogate marker showed that all the compounds had no effects on the neurite elongation up to 1 μM. Extensive docking simulation and binding structure prediction of the four compounds with all available human proteins using AutoDock Vina and DiffDock showed that the four compounds were unlikely to directly bind to MuSK or Dok7, and the exact target remained unknown. The identified compounds are expected to serve as a seed to develop a novel therapeutic agent to treat defective NMJ signal transmission.
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Affiliation(s)
- Yuichi Miyairi
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan; Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Bisei Ohkawara
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Ayato Sato
- Institute for Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan; Center for One Medicine Innovative Translational Research (COMIT), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan.
| | - Ryusuke Sawada
- Department of Pharmacology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan.
| | - Hisao Ishii
- Department of Hand Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Hiroyuki Tomita
- Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Taro Inoue
- Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Hiroaki Nakashima
- Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Mikako Ito
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Akio Masuda
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Yasuyuki Hosono
- Department of Pharmacology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan.
| | - Shiro Imagama
- Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan.
| | - Kinji Ohno
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan; Graduate School of Nutritoinal Sciencess, Nagoya University of Arts and Sciences, 57 Takenoyama, Iwasaki, Nisshin, 470-0196, Japan.
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Suarez GO, Kumar DS, Brunner H, Emel J, Teel J, Knauss A, Botero V, Broyles CN, Stahl A, Bidaye SS, Tomchik SM. Neurofibromin deficiency alters the patterning and prioritization of motor behaviors in a state-dependent manner. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.08.607070. [PMID: 39149363 PMCID: PMC11326213 DOI: 10.1101/2024.08.08.607070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Genetic disorders such as neurofibromatosis type 1 increase vulnerability to cognitive and behavioral disorders, such as autism spectrum disorder and attention-deficit/hyperactivity disorder. Neurofibromatosis type 1 results from loss-of-function mutations in the neurofibromin gene and subsequent reduction in the neurofibromin protein (Nf1). While the mechanisms have yet to be fully elucidated, loss of Nf1 may alter neuronal circuit activity leading to changes in behavior and susceptibility to cognitive and behavioral comorbidities. Here we show that mutations decreasing Nf1 expression alter motor behaviors, impacting the patterning, prioritization, and behavioral state dependence in a Drosophila model of neurofibromatosis type 1. Loss of Nf1 increases spontaneous grooming in a nonlinear spatial and temporal pattern, differentially increasing grooming of certain body parts, including the abdomen, head, and wings. This increase in grooming could be overridden by hunger in food-deprived foraging animals, demonstrating that the Nf1 effect is plastic and internal state-dependent. Stimulus-evoked grooming patterns were altered as well, with nf1 mutants exhibiting reductions in wing grooming when coated with dust, suggesting that hierarchical recruitment of grooming command circuits was altered. Yet loss of Nf1 in sensory neurons and/or grooming command neurons did not alter grooming frequency, suggesting that Nf1 affects grooming via higher-order circuit alterations. Changes in grooming coincided with alterations in walking. Flies lacking Nf1 walked with increased forward velocity on a spherical treadmill, yet there was no detectable change in leg kinematics or gait. Thus, loss of Nf1 alters motor function without affecting overall motor coordination, in contrast to other genetic disorders that impair coordination. Overall, these results demonstrate that loss of Nf1 alters the patterning and prioritization of repetitive behaviors, in a state-dependent manner, without affecting motor coordination.
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Affiliation(s)
- Genesis Omana Suarez
- Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
- H.L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Divya S. Kumar
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, USA
| | - Hannah Brunner
- Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Jalen Emel
- Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Jensen Teel
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, USA
| | - Anneke Knauss
- Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Valentina Botero
- Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Connor N. Broyles
- Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Aaron Stahl
- Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Salil S. Bidaye
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, USA
| | - Seth M. Tomchik
- Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
- Stead Family Department of Pediatrics, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
- H.L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
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3
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Stahl A, Tomchik SM. Modeling neurodegenerative and neurodevelopmental disorders in the Drosophila mushroom body. Learn Mem 2024; 31:a053816. [PMID: 38876485 PMCID: PMC11199955 DOI: 10.1101/lm.053816.123] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 05/01/2024] [Indexed: 06/16/2024]
Abstract
The common fruit fly Drosophila melanogaster provides a powerful platform to investigate the genetic, molecular, cellular, and neural circuit mechanisms of behavior. Research in this model system has shed light on multiple aspects of brain physiology and behavior, from fundamental neuronal function to complex behaviors. A major anatomical region that modulates complex behaviors is the mushroom body (MB). The MB integrates multimodal sensory information and is involved in behaviors ranging from sensory processing/responses to learning and memory. Many genes that underlie brain disorders are conserved, from flies to humans, and studies in Drosophila have contributed significantly to our understanding of the mechanisms of brain disorders. Genetic mutations that mimic human diseases-such as Fragile X syndrome, neurofibromatosis type 1, Parkinson's disease, and Alzheimer's disease-affect MB structure and function, altering behavior. Studies dissecting the effects of disease-causing mutations in the MB have identified key pathological mechanisms, and the development of a complete connectome promises to add a comprehensive anatomical framework for disease modeling. Here, we review Drosophila models of human neurodevelopmental and neurodegenerative disorders via the effects of their underlying mutations on MB structure, function, and the resulting behavioral alterations.
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Affiliation(s)
- Aaron Stahl
- Neuroscience and Pharmacology, University of Iowa, Iowa City, Iowa 52242, USA
| | - Seth M Tomchik
- Neuroscience and Pharmacology, University of Iowa, Iowa City, Iowa 52242, USA
- Stead Family Department of Pediatrics, University of Iowa, Iowa City, Iowa 52242, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
- Hawk-IDDRC, University of Iowa, Iowa City, Iowa 52242, USA
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4
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Atsoniou K, Giannopoulou E, Georganta EM, Skoulakis EMC. Drosophila Contributions towards Understanding Neurofibromatosis 1. Cells 2024; 13:721. [PMID: 38667335 PMCID: PMC11048932 DOI: 10.3390/cells13080721] [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: 03/15/2024] [Revised: 04/17/2024] [Accepted: 04/19/2024] [Indexed: 04/28/2024] Open
Abstract
Neurofibromatosis 1 (NF1) is a multisymptomatic disorder with highly variable presentations, which include short stature, susceptibility to formation of the characteristic benign tumors known as neurofibromas, intense freckling and skin discoloration, and cognitive deficits, which characterize most children with the condition. Attention deficits and Autism Spectrum manifestations augment the compromised learning presented by most patients, leading to behavioral problems and school failure, while fragmented sleep contributes to chronic fatigue and poor quality of life. Neurofibromin (Nf1) is present ubiquitously during human development and postnatally in most neuronal, oligodendrocyte, and Schwann cells. Evidence largely from animal models including Drosophila suggests that the symptomatic variability may reflect distinct cell-type-specific functions of the protein, which emerge upon its loss, or mutations affecting the different functional domains of the protein. This review summarizes the contributions of Drosophila in modeling multiple NF1 manifestations, addressing hypotheses regarding the cell-type-specific functions of the protein and exploring the molecular pathways affected upon loss of the highly conserved fly homolog dNf1. Collectively, work in this model not only has efficiently and expediently modelled multiple aspects of the condition and increased understanding of its behavioral manifestations, but also has led to pharmaceutical strategies towards their amelioration.
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Affiliation(s)
- Kalliopi Atsoniou
- Institute for Fundamental Biomedical Research, Biomedical Sciences Research Center “Alexander Fleming”, 16672 Athens, Greece; (K.A.); (E.G.)
- Laboratory of Experimental Physiology, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - Eleni Giannopoulou
- Institute for Fundamental Biomedical Research, Biomedical Sciences Research Center “Alexander Fleming”, 16672 Athens, Greece; (K.A.); (E.G.)
| | - Eirini-Maria Georganta
- Institute for Fundamental Biomedical Research, Biomedical Sciences Research Center “Alexander Fleming”, 16672 Athens, Greece; (K.A.); (E.G.)
| | - Efthimios M. C. Skoulakis
- Institute for Fundamental Biomedical Research, Biomedical Sciences Research Center “Alexander Fleming”, 16672 Athens, Greece; (K.A.); (E.G.)
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Cherra SJ, Lamb R. Interactions between Ras and Rap signaling pathways during neurodevelopment in health and disease. Front Mol Neurosci 2024; 17:1352731. [PMID: 38463630 PMCID: PMC10920261 DOI: 10.3389/fnmol.2024.1352731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 02/08/2024] [Indexed: 03/12/2024] Open
Abstract
The Ras family of small GTPases coordinates tissue development by modulating cell proliferation, cell-cell adhesion, and cellular morphology. Perturbations of any of these key steps alter nervous system development and are associated with neurological disorders. While the underlying causes are not known, genetic mutations in Ras and Rap GTPase signaling pathways have been identified in numerous neurodevelopmental disorders, including autism spectrum, neurofibromatosis, intellectual disability, epilepsy, and schizophrenia. Despite diverse clinical presentations, intersections between these two signaling pathways may provide a better understanding of how deviations in neurodevelopment give rise to neurological disorders. In this review, we focus on presynaptic and postsynaptic functions of Ras and Rap GTPases. We highlight various roles of these small GTPases during synapse formation and plasticity. Based on genomic analyses, we discuss how disease-related mutations in Ras and Rap signaling proteins may underlie human disorders. Finally, we discuss how recent observations have identified molecular interactions between these pathways and how these findings may provide insights into the mechanisms that underlie neurodevelopmental disorders.
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Affiliation(s)
- Salvatore J. Cherra
- Department of Neuroscience, University of Kentucky College of Medicine, Lexington, KY, United States
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6
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Staedtke V, Topilko P, Le LQ, Grimes K, Largaespada DA, Cagan RL, Steensma MR, Stemmer-Rachamimov A, Blakeley JO, Rhodes SD, Ly I, Romo CG, Lee SY, Serra E. Existing and Developing Preclinical Models for Neurofibromatosis Type 1-Related Cutaneous Neurofibromas. J Invest Dermatol 2023; 143:1378-1387. [PMID: 37330719 PMCID: PMC11246562 DOI: 10.1016/j.jid.2023.01.042] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/17/2023] [Accepted: 01/19/2023] [Indexed: 06/19/2023]
Abstract
Neurofibromatosis type 1 (NF1) is caused by a nonfunctional copy of the NF1 tumor suppressor gene that predisposes patients to the development of cutaneous neurofibromas (cNFs), the skin tumor that is the hallmark of this condition. Innumerable benign cNFs, each appearing by an independent somatic inactivation of the remaining functional NF1 allele, form in nearly all patients with NF1. One of the limitations in developing a treatment for cNFs is an incomplete understanding of the underlying pathophysiology and limitations in experimental modeling. Recent advances in preclinical in vitro and in vivo modeling have substantially enhanced our understanding of cNF biology and created unprecedented opportunities for therapeutic discovery. We discuss the current state of cNF preclinical in vitro and in vivo model systems, including two- and three-dimensional cell cultures, organoids, genetically engineered mice, patient-derived xenografts, and porcine models. We highlight the models' relationship to human cNFs and how they can be used to gain insight into cNF development and therapeutic discovery.
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Affiliation(s)
- Verena Staedtke
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
| | - Piotr Topilko
- Institut Mondor de Recherche Biomédicale (IMRB), Créteil, France
| | - Lu Q Le
- Department of Dermatology, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Kevin Grimes
- SPARK Program in Translational Research, Stanford University School of Medicine, Stanford, California, USA; Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California, USA
| | - David A Largaespada
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, USA
| | - Ross L Cagan
- School of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Matthew R Steensma
- Center for Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan, USA; Helen DeVos Children's Hospital, Spectrum Health System, Grand Rapids, Michigan, USA; Michigan State University College of Human Medicine, Grand Rapids, Michigan, USA
| | - Anat Stemmer-Rachamimov
- Department of Pathology and Center for Cancer Research, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Jaishri O Blakeley
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Steven D Rhodes
- Division of Hematology-Oncology, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana, USA; Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana, USA; Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, USA; Indiana University Melvin and Bren Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Ina Ly
- Stephen E. and Catherine Pappas Center for Neuro-Oncology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Carlos G Romo
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Sang Y Lee
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Eduard Serra
- Hereditary Cancer Group, Germans Trias i Pujol Research Institute (IGTP), Can Ruti Campus, Barcelona, Spain; Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Madrid, Spain
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7
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Katanaev VL. Humanization for neurological disease modeling: A roadmap to increase the potential of Drosophila model systems. Animal Model Exp Med 2023; 6:230-236. [PMID: 37323110 PMCID: PMC10272901 DOI: 10.1002/ame2.12322] [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: 01/11/2023] [Accepted: 04/03/2023] [Indexed: 06/17/2023] Open
Abstract
Neuroscience and neurology research is dominated by experimentation with rodents. Around 75% of neurology disease-associated genes have orthologs in Drosophila melanogaster, the fruit fly amenable to complex neurological and behavioral investigations. However, non-vertebrate models including Drosophila have so far been unable to significantly replace mice and rats in this field of studies. One reason for this situation is the predominance of gene overexpression (and gene loss-of-function) methodologies used when establishing a Drosophila model of a given neurological disease, a strategy that does not recapitulate accurately enough the genetic disease conditions. I argue here the need for a systematic humanization approach, whereby the Drosophila orthologs of human disease genes are replaced with the human sequences. This approach will identify the list of diseases and the underlying genes that can be adequately modeled in the fruit fly. I discuss the neurological disease genes to which this systematic humanization approach should be applied and provide an example of such an application, and consider its importance for subsequent disease modeling and drug discovery in Drosophila. I argue that this paradigm will not only advance our understanding of the molecular etiology of a number of neurological disorders, but will also gradually enable researchers to reduce experimentation using rodent models of multiple neurological diseases and eventually replace these models.
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Affiliation(s)
- Vladimir L. Katanaev
- Department of Cell Physiology and Metabolism, Faculty of MedicineUniversity of GenevaGenevaSwitzerland
- HumanaFly Facility, Faculty of MedicineUniversity of GenevaGenevaSwitzerland
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Báez-Flores J, Rodríguez-Martín M, Lacal J. The therapeutic potential of neurofibromin signaling pathways and binding partners. Commun Biol 2023; 6:436. [PMID: 37081086 PMCID: PMC10119308 DOI: 10.1038/s42003-023-04815-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 04/05/2023] [Indexed: 04/22/2023] Open
Abstract
Neurofibromin controls many cell processes, such as growth, learning, and memory. If neurofibromin is not working properly, it can lead to health problems, including issues with the nervous, skeletal, and cardiovascular systems and cancer. This review examines neurofibromin's binding partners, signaling pathways and potential therapeutic targets. In addition, it summarizes the different post-translational modifications that can affect neurofibromin's interactions with other molecules. It is essential to investigate the molecular mechanisms that underlie neurofibromin variants in order to provide with functional connections between neurofibromin and its associated proteins for possible therapeutic targets based on its biological function.
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Affiliation(s)
- Juan Báez-Flores
- Laboratory of Functional Genetics of Rare Diseases, Department of Microbiology and Genetics, University of Salamanca (USAL), 37007, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), 37007, Salamanca, Spain
| | - Mario Rodríguez-Martín
- Laboratory of Functional Genetics of Rare Diseases, Department of Microbiology and Genetics, University of Salamanca (USAL), 37007, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), 37007, Salamanca, Spain
| | - Jesus Lacal
- Laboratory of Functional Genetics of Rare Diseases, Department of Microbiology and Genetics, University of Salamanca (USAL), 37007, Salamanca, Spain.
- Institute of Biomedical Research of Salamanca (IBSAL), 37007, Salamanca, Spain.
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9
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Miller AH, Halloran MC. Mechanistic insights from animal models of neurofibromatosis type 1 cognitive impairment. Dis Model Mech 2022; 15:276464. [PMID: 36037004 PMCID: PMC9459395 DOI: 10.1242/dmm.049422] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Neurofibromatosis type 1 (NF1) is an autosomal-dominant neurogenetic disorder caused by mutations in the gene neurofibromin 1 (NF1). NF1 predisposes individuals to a variety of symptoms, including peripheral nerve tumors, brain tumors and cognitive dysfunction. Cognitive deficits can negatively impact patient quality of life, especially the social and academic development of children. The neurofibromin protein influences neural circuits via diverse cellular signaling pathways, including through RAS, cAMP and dopamine signaling. Although animal models have been useful in identifying cellular and molecular mechanisms that regulate NF1-dependent behaviors, translating these discoveries into effective treatments has proven difficult. Clinical trials measuring cognitive outcomes in patients with NF1 have mainly targeted RAS signaling but, unfortunately, resulted in limited success. In this Review, we provide an overview of the structure and function of neurofibromin, and evaluate several cellular and molecular mechanisms underlying neurofibromin-dependent cognitive function, which have recently been delineated in animal models. A better understanding of neurofibromin roles in the development and function of the nervous system will be crucial for identifying new therapeutic targets for the various cognitive domains affected by NF1. Summary: Neurofibromin influences neural circuits through RAS, cAMP and dopamine signaling. Exploring the mechanisms underlying neurofibromin-dependent behaviors in animal models might enable future treatment of the various cognitive deficits that are associated with neurofibromatosis type 1.
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Affiliation(s)
- Andrew H Miller
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA.,Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53705, USA.,Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Mary C Halloran
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA.,Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53705, USA
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10
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Chaker-Margot M, Werten S, Dunzendorfer-Matt T, Lechner S, Ruepp A, Scheffzek K, Maier T. Structural basis of activation of the tumor suppressor protein neurofibromin. Mol Cell 2022; 82:1288-1296.e5. [PMID: 35353986 DOI: 10.1016/j.molcel.2022.03.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/14/2022] [Accepted: 03/03/2022] [Indexed: 12/15/2022]
Abstract
Mutations in the NF1 gene cause the familial genetic disease neurofibromatosis type I, as well as predisposition to cancer. The NF1 gene product, neurofibromin, is a GTPase-activating protein and acts as a tumor suppressor by negatively regulating the small GTPase, Ras. However, structural insights into neurofibromin activation remain incompletely defined. Here, we provide cryoelectron microscopy (cryo-EM) structures that reveal an extended neurofibromin homodimer in two functional states: an auto-inhibited state with occluded Ras-binding site and an asymmetric open state with an exposed Ras-binding site. Mechanistically, the transition to the active conformation is stimulated by nucleotide binding, which releases a lock that tethers the catalytic domain to an extended helical repeat scaffold in the occluded state. Structure-guided mutational analysis supports functional relevance of allosteric control. Disease-causing mutations are mapped and primarily impact neurofibromin stability. Our findings suggest a role for nucleotides in neurofibromin regulation and may lead to therapeutic modulation of Ras signaling.
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Affiliation(s)
| | - Sebastiaan Werten
- Institute of Biological Chemistry, Biocenter, Medical University of Innsbruck, Innsbruck 6020, Austria
| | | | - Stefan Lechner
- Institute of Biological Chemistry, Biocenter, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Angela Ruepp
- Institute of Biological Chemistry, Biocenter, Medical University of Innsbruck, Innsbruck 6020, Austria
| | - Klaus Scheffzek
- Institute of Biological Chemistry, Biocenter, Medical University of Innsbruck, Innsbruck 6020, Austria.
| | - Timm Maier
- Biozentrum, University of Basel, 4056 Basel, Switzerland.
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11
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Somatilaka BN, Sadek A, McKay RM, Le LQ. Malignant peripheral nerve sheath tumor: models, biology, and translation. Oncogene 2022; 41:2405-2421. [PMID: 35393544 PMCID: PMC9035132 DOI: 10.1038/s41388-022-02290-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 03/16/2022] [Accepted: 03/21/2022] [Indexed: 01/29/2023]
Abstract
Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive, invasive cancer that comprise around 10% of all soft tissue sarcomas and develop in about 8-13% of patients with Neurofibromatosis Type 1. They are associated with poor prognosis and are the leading cause of mortality in NF1 patients. MPNSTs can also develop sporadically or following exposure to radiation. There is currently no effective targeted therapy to treat MPNSTs and surgical removal remains the mainstay treatment. Unfortunately, surgery is not always possible due to the size and location of the tumor, thus, a better understanding of MPNST initiation and development is required to design novel therapeutics. Here, we provide an overview of MPNST biology and genetics, discuss findings regarding the developmental origin of MPNST, and summarize the various model systems employed to study MPNST. Finally, we discuss current management strategies for MPNST, as well as recent developments in translating basic research findings into potential therapies.
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Affiliation(s)
- Bandarigoda N. Somatilaka
- Department of Dermatology, University of Texas Southwestern
Medical Center at Dallas, Dallas, Texas, 75390-9069, USA
| | - Ali Sadek
- Department of Dermatology, University of Texas Southwestern
Medical Center at Dallas, Dallas, Texas, 75390-9069, USA
| | - Renee M. McKay
- Department of Dermatology, University of Texas Southwestern
Medical Center at Dallas, Dallas, Texas, 75390-9069, USA
| | - Lu Q. Le
- Department of Dermatology, University of Texas Southwestern
Medical Center at Dallas, Dallas, Texas, 75390-9069, USA,Simmons Comprehensive Cancer Center, University of Texas
Southwestern Medical Center at Dallas, Dallas, Texas, 75390-9069, USA,UTSW Comprehensive Neurofibromatosis Clinic, University of
Texas Southwestern Medical Center at Dallas, Dallas, Texas, 75390-9069, USA,Hamon Center for Regenerative Science and Medicine,
University of Texas Southwestern Medical Center at Dallas, Dallas, Texas,
75390-9069, USA,O’Donnell Brain Institute, University of Texas
Southwestern Medical Center at Dallas, Dallas, Texas, 75390-9069, USA
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12
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Anastasaki C, Orozco P, Gutmann DH. RAS and beyond: the many faces of the neurofibromatosis type 1 protein. Dis Model Mech 2022; 15:274437. [PMID: 35188187 PMCID: PMC8891636 DOI: 10.1242/dmm.049362] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Neurofibromatosis type 1 is a rare neurogenetic syndrome, characterized by pigmentary abnormalities, learning and social deficits, and a predisposition for benign and malignant tumor formation caused by germline mutations in the NF1 gene. With the cloning of the NF1 gene and the recognition that the encoded protein, neurofibromin, largely functions as a negative regulator of RAS activity, attention has mainly focused on RAS and canonical RAS effector pathway signaling relevant to disease pathogenesis and treatment. However, as neurofibromin is a large cytoplasmic protein the RAS regulatory domain of which occupies only 10% of its entire coding sequence, both canonical and non-canonical RAS pathway modulation, as well as the existence of potential non-RAS functions, are becoming apparent. In this Special article, we discuss our current understanding of neurofibromin function.
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Affiliation(s)
- Corina Anastasaki
- Department of Neurology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Paola Orozco
- Department of Neurology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - David H Gutmann
- Department of Neurology, Washington University School of Medicine, St Louis, MO 63110, USA
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13
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Mo J, Moye SL, McKay RM, Le LQ. Neurofibromin and suppression of tumorigenesis: beyond the GAP. Oncogene 2022; 41:1235-1251. [PMID: 35066574 PMCID: PMC9063229 DOI: 10.1038/s41388-021-02156-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/01/2021] [Accepted: 12/13/2021] [Indexed: 12/15/2022]
Abstract
Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic disease and one of the most common inherited tumor predisposition syndromes, affecting 1 in 3000 individuals worldwide. The NF1 gene encodes neurofibromin, a large protein with RAS GTP-ase activating (RAS-GAP) activity, and loss of NF1 results in increased RAS signaling. Neurofibromin contains many other domains, and there is considerable evidence that these domains play a role in some manifestations of NF1. Investigating the role of these domains as well as the various signaling pathways that neurofibromin regulates and interacts with will provide a better understanding of how neurofibromin acts to suppress tumor development and potentially open new therapeutic avenues. In this review, we discuss what is known about the structure of neurofibromin, its interactions with other proteins and signaling pathways, its role in development and differentiation, and its function as a tumor suppressor. Finally, we discuss the latest research on potential therapeutics for neurofibromin-deficient neoplasms.
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Affiliation(s)
- Juan Mo
- Department of Dermatology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, 75390-9069, USA
| | - Stefanie L Moye
- Department of Dermatology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, 75390-9069, USA
| | - Renee M McKay
- Department of Dermatology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, 75390-9069, USA
| | - Lu Q Le
- Department of Dermatology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, 75390-9069, USA.
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, 75390-9069, USA.
- UTSW Comprehensive Neurofibromatosis Clinic, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, 75390-9069, USA.
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, 75390-9069, USA.
- O'Donnell Brain Institute, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, 75390-9069, USA.
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14
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Machado Almeida P, Lago Solis B, Stickley L, Feidler A, Nagoshi E. Neurofibromin 1 in mushroom body neurons mediates circadian wake drive through activating cAMP-PKA signaling. Nat Commun 2021; 12:5758. [PMID: 34599173 PMCID: PMC8486785 DOI: 10.1038/s41467-021-26031-2] [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] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 09/15/2021] [Indexed: 02/08/2023] Open
Abstract
Various behavioral and cognitive states exhibit circadian variations in animals across phyla including Drosophila melanogaster, in which only ~0.1% of the brain's neurons contain circadian clocks. Clock neurons transmit the timing information to a plethora of non-clock neurons via poorly understood mechanisms. Here, we address the molecular underpinning of this phenomenon by profiling circadian gene expression in non-clock neurons that constitute the mushroom body, the center of associative learning and sleep regulation. We show that circadian clocks drive rhythmic expression of hundreds of genes in mushroom body neurons, including the Neurofibromin 1 (Nf1) tumor suppressor gene and Pka-C1. Circadian clocks also drive calcium rhythms in mushroom body neurons via NF1-cAMP/PKA-C1 signaling, eliciting higher mushroom body activity during the day than at night, thereby promoting daytime wakefulness. These findings reveal the pervasive, non-cell-autonomous circadian regulation of gene expression in the brain and its role in sleep.
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Affiliation(s)
- Pedro Machado Almeida
- grid.8591.50000 0001 2322 4988Department of Genetics and Evolution, Sciences III, University of Geneva, 30 Quai Ernest-Ansermet, Geneva, 4, CH-1211 Switzerland
| | - Blanca Lago Solis
- grid.8591.50000 0001 2322 4988Department of Genetics and Evolution, Sciences III, University of Geneva, 30 Quai Ernest-Ansermet, Geneva, 4, CH-1211 Switzerland
| | - Luca Stickley
- grid.8591.50000 0001 2322 4988Department of Genetics and Evolution, Sciences III, University of Geneva, 30 Quai Ernest-Ansermet, Geneva, 4, CH-1211 Switzerland
| | - Alexis Feidler
- grid.8591.50000 0001 2322 4988Department of Genetics and Evolution, Sciences III, University of Geneva, 30 Quai Ernest-Ansermet, Geneva, 4, CH-1211 Switzerland ,grid.412750.50000 0004 1936 9166Present Address: University of Rochester School of Medicine and Dentistry, Rochester, NY USA
| | - Emi Nagoshi
- grid.8591.50000 0001 2322 4988Department of Genetics and Evolution, Sciences III, University of Geneva, 30 Quai Ernest-Ansermet, Geneva, 4, CH-1211 Switzerland
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15
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Georganta EM, Moressis A, Skoulakis EMC. Associative Learning Requires Neurofibromin to Modulate GABAergic Inputs to Drosophila Mushroom Bodies. J Neurosci 2021; 41:5274-5286. [PMID: 33972401 PMCID: PMC8211548 DOI: 10.1523/jneurosci.1605-20.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 04/12/2021] [Accepted: 04/15/2021] [Indexed: 12/28/2022] Open
Abstract
Cognitive dysfunction is among the hallmark symptoms of Neurofibromatosis 1, and accordingly, loss of the Drosophila melanogaster ortholog of Neurofibromin 1 (dNf1) precipitates associative learning deficits. However, the affected circuitry in the adult CNS remained unclear and the compromised mechanisms debatable. Although the main evolutionarily conserved function attributed to Nf1 is to inactivate Ras, decreased cAMP signaling on its loss has been thought to underlie impaired learning. Using mixed sex populations, we determine that dNf1 loss results in excess GABAergic signaling to the central for associative learning mushroom body (MB) neurons, apparently suppressing learning. dNf1 is necessary and sufficient for learning within these non-MB neurons, as a dAlk and Ras1-dependent, but PKA-independent modulator of GABAergic neurotransmission. Surprisingly, we also uncovered and discuss a postsynaptic Ras1-dependent, but dNf1-independnet signaling within the MBs that apparently responds to presynaptic GABA levels and contributes to the learning deficit of the mutants.
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Affiliation(s)
- Eirini-Maria Georganta
- Institute for Fundamental Biomedical Research, Biomedical Sciences Research Center "Alexander Fleming" Vari, 16672, Greece
| | - Anastasios Moressis
- Institute for Fundamental Biomedical Research, Biomedical Sciences Research Center "Alexander Fleming" Vari, 16672, Greece
| | - Efthimios M C Skoulakis
- Institute for Fundamental Biomedical Research, Biomedical Sciences Research Center "Alexander Fleming" Vari, 16672, Greece
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16
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Vcp Overexpression and Leucine Supplementation Increase Protein Synthesis and Improve Fear Memory and Social Interaction of Nf1 Mutant Mice. Cell Rep 2021; 31:107835. [PMID: 32610136 DOI: 10.1016/j.celrep.2020.107835] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 03/25/2020] [Accepted: 06/08/2020] [Indexed: 11/22/2022] Open
Abstract
Neurofibromatosis type 1 (NF1) is a dominant genetic disorder manifesting, in part, as cognitive defects. Previous study indicated that neurofibromin (NF1 protein) interacts with valosin-containing protein (VCP)/P97 to control dendritic spine formation, but the mechanism is unknown. Here, using Nf1+/- mice and transgenic mice overexpressing wild-type Vcp/p97, we demonstrate that neurofibromin acts with VCP to control endoplasmic reticulum (ER) formation and consequent protein synthesis and regulates dendritic spine formation, thereby modulating contextual fear memory and social interaction. To validate the role of protein synthesis, we perform leucine supplementation in vitro and in vivo. Our results suggest that leucine can effectively enter the brain and increase protein synthesis and dendritic spine density of Nf1+/- neurons. Contextual memory and social behavior of Nf1+/- mice are also restored by leucine supplementation. Our study suggests that the "ER-protein synthesis" pathway downstream of neurofibromin and VCP is a critical regulator of dendritic spinogenesis and brain function.
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17
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Using antisense oligonucleotides for the physiological modulation of the alternative splicing of NF1 exon 23a during PC12 neuronal differentiation. Sci Rep 2021; 11:3661. [PMID: 33574490 PMCID: PMC7878752 DOI: 10.1038/s41598-021-83152-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 01/29/2021] [Indexed: 01/11/2023] Open
Abstract
Neurofibromatosis Type 1 (NF1) is a genetic condition affecting approximately 1:3500 persons worldwide. The NF1 gene codes for neurofibromin protein, a GTPase activating protein (GAP) and a negative regulator of RAS. The NF1 gene undergoes alternative splicing of exon 23a (E23a) that codes for 21 amino acids placed at the center of the GAP related domain (GRD). E23a-containing type II neurofibromin exhibits a weaker Ras-GAP activity compared to E23a-less type I isoform. Exon E23a has been related with the cognitive impairment present in NF1 individuals. We designed antisense Phosphorodiamidate Morpholino Oligomers (PMOs) to modulate E23a alternative splicing at physiological conditions of gene expression and tested their impact during PC12 cell line neuronal differentiation. Results show that any dynamic modification of the natural ratio between type I and type II isoforms disturbed neuronal differentiation, altering the proper formation of neurites and deregulating both the MAPK/ERK and cAMP/PKA signaling pathways. Our results suggest an opposite regulation of these pathways by neurofibromin and the possible existence of a feedback loop sensing neurofibromin-related signaling. The present work illustrates the utility of PMOs to study alternative splicing that could be applied to other alternatively spliced genes in vitro and in vivo.
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18
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MEKK2 mediates aberrant ERK activation in neurofibromatosis type I. Nat Commun 2020; 11:5704. [PMID: 33177525 PMCID: PMC7658220 DOI: 10.1038/s41467-020-19555-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 10/14/2020] [Indexed: 12/14/2022] Open
Abstract
Neurofibromatosis type I (NF1) is characterized by prominent skeletal manifestations caused by NF1 loss. While inhibitors of the ERK activating kinases MEK1/2 are promising as a means to treat NF1, the broad blockade of the ERK pathway produced by this strategy is potentially associated with therapy limiting toxicities. Here, we have sought targets offering a more narrow inhibition of ERK activation downstream of NF1 loss in the skeleton, finding that MEKK2 is a novel component of a noncanonical ERK pathway in osteoblasts that mediates aberrant ERK activation after NF1 loss. Accordingly, despite mice with conditional deletion of Nf1 in mature osteoblasts (Nf1fl/fl;Dmp1-Cre) and Mekk2−/− each displaying skeletal defects, Nf1fl/fl;Mekk2−/−;Dmp1-Cre mice show an amelioration of NF1-associated phenotypes. We also provide proof-of-principle that FDA-approved inhibitors with activity against MEKK2 can ameliorate NF1 skeletal pathology. Thus, MEKK2 functions as a MAP3K in the ERK pathway in osteoblasts, offering a potential new therapeutic strategy for the treatment of NF1. Neurofibromatosis type I (NF1) is characterized by prominent skeletal abnormalities mediated in part by aberrant ERK pathway activation due to NF1 loss-of-function. Here, the authors report the MEKK2 is a key mediator of this aberrant ERK activation and that MEKK2 inhibitors, including ponatinib, ameliorate skeletal defects in a mouse model of NF1.
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19
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Bergoug M, Doudeau M, Godin F, Mosrin C, Vallée B, Bénédetti H. Neurofibromin Structure, Functions and Regulation. Cells 2020; 9:cells9112365. [PMID: 33121128 PMCID: PMC7692384 DOI: 10.3390/cells9112365] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/21/2020] [Accepted: 10/26/2020] [Indexed: 12/13/2022] Open
Abstract
Neurofibromin is a large and multifunctional protein encoded by the tumor suppressor gene NF1, mutations of which cause the tumor predisposition syndrome neurofibromatosis type 1 (NF1). Over the last three decades, studies of neurofibromin structure, interacting partners, and functions have shown that it is involved in several cell signaling pathways, including the Ras/MAPK, Akt/mTOR, ROCK/LIMK/cofilin, and cAMP/PKA pathways, and regulates many fundamental cellular processes, such as proliferation and migration, cytoskeletal dynamics, neurite outgrowth, dendritic-spine density, and dopamine levels. The crystallographic structure has been resolved for two of its functional domains, GRD (GAP-related (GTPase-activating protein) domain) and SecPH, and its post-translational modifications studied, showing it to be localized to several cell compartments. These findings have been of particular interest in the identification of many therapeutic targets and in the proposal of various therapeutic strategies to treat the symptoms of NF1. In this review, we provide an overview of the literature on neurofibromin structure, function, interactions, and regulation and highlight the relationships between them.
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20
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King LB, Boto T, Botero V, Aviles AM, Jomsky BM, Joseph C, Walker JA, Tomchik SM. Developmental loss of neurofibromin across distributed neuronal circuits drives excessive grooming in Drosophila. PLoS Genet 2020; 16:e1008920. [PMID: 32697780 PMCID: PMC7398555 DOI: 10.1371/journal.pgen.1008920] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 08/03/2020] [Accepted: 06/08/2020] [Indexed: 02/06/2023] Open
Abstract
Neurofibromatosis type 1 is a monogenetic disorder that predisposes individuals to tumor formation and cognitive and behavioral symptoms. The neuronal circuitry and developmental events underlying these neurological symptoms are unknown. To better understand how mutations of the underlying gene (NF1) drive behavioral alterations, we have examined grooming in the Drosophila neurofibromatosis 1 model. Mutations of the fly NF1 ortholog drive excessive grooming, and increased grooming was observed in adults when Nf1 was knocked down during development. Furthermore, intact Nf1 Ras GAP-related domain signaling was required to maintain normal grooming. The requirement for Nf1 was distributed across neuronal circuits, which were additive when targeted in parallel, rather than mapping to discrete microcircuits. Overall, these data suggest that broadly-distributed alterations in neuronal function during development, requiring intact Ras signaling, drive key Nf1-mediated behavioral alterations. Thus, global developmental alterations in brain circuits/systems function may contribute to behavioral phenotypes in neurofibromatosis type 1.
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Affiliation(s)
- Lanikea B. King
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Tamara Boto
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Valentina Botero
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Ari M. Aviles
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States of America
- Honors College, Florida Atlantic University, Jupiter, Florida, United States of America
| | - Breanna M. Jomsky
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States of America
- Honors College, Florida Atlantic University, Jupiter, Florida, United States of America
| | - Chevara Joseph
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States of America
- Honors College, Florida Atlantic University, Jupiter, Florida, United States of America
| | - James A. Walker
- Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School, Cambridge, Massachusetts, United States of America
| | - Seth M. Tomchik
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States of America
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21
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Sutton LP, Muntean BS, Ostrovskaya O, Zucca S, Dao M, Orlandi C, Song C, Xie K, Martemyanov KA. NF1-cAMP signaling dissociates cell type-specific contributions of striatal medium spiny neurons to reward valuation and motor control. PLoS Biol 2019; 17:e3000477. [PMID: 31600280 PMCID: PMC6805008 DOI: 10.1371/journal.pbio.3000477] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 10/22/2019] [Accepted: 09/17/2019] [Indexed: 12/11/2022] Open
Abstract
The striatum plays a fundamental role in motor learning and reward-related behaviors that are synergistically shaped by populations of D1 dopamine receptor (D1R)- and D2 dopamine receptor (D2R)-expressing medium spiny neurons (MSNs). How various neurotransmitter inputs converging on common intracellular pathways are parsed out to regulate distinct behavioral outcomes in a neuron-specific manner is poorly understood. Here, we reveal that distinct contributions of D1R-MSNs and D2R-MSNs towards reward and motor behaviors are delineated by the multifaceted signaling protein neurofibromin 1 (NF1). Using genetic mouse models, we show that NF1 in D1R-MSN modulates opioid reward, whereas loss of NF1 in D2R-MSNs delays motor learning by impeding the formation and consolidation of repetitive motor sequences. We found that motor learning deficits upon NF1 loss were associated with the disruption in dopamine signaling to cAMP in D2R-MSN. Restoration of cAMP levels pharmacologically or chemogenetically rescued the motor learning deficits seen upon NF1 loss in D2R-MSN. Our findings illustrate that multiplex signaling capabilities of MSNs are deployed at the level of intracellular pathways to achieve cell-specific control over behavioral outcomes. A mouse genetic study reveals that the multifaceted signaling protein neurofibromin (known for its role in the human genetic disease neurofibromatosis type 1) plays a key role in differential routing of motor and reward signals in populations of striatal medium spiny neurons.
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Affiliation(s)
- Laurie P. Sutton
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Brian S. Muntean
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Olga Ostrovskaya
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Stefano Zucca
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Maria Dao
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Cesare Orlandi
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Chenghui Song
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Keqiang Xie
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Kirill A. Martemyanov
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, United States of America
- * E-mail:
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22
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Coll-Tané M, Krebbers A, Castells-Nobau A, Zweier C, Schenck A. Intellectual disability and autism spectrum disorders 'on the fly': insights from Drosophila. Dis Model Mech 2019; 12:dmm039180. [PMID: 31088981 PMCID: PMC6550041 DOI: 10.1242/dmm.039180] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Intellectual disability (ID) and autism spectrum disorders (ASD) are frequently co-occurring neurodevelopmental disorders and affect 2-3% of the population. Rapid advances in exome and genome sequencing have increased the number of known implicated genes by threefold, to more than a thousand. The main challenges in the field are now to understand the various pathomechanisms associated with this bewildering number of genetic disorders, to identify new genes and to establish causality of variants in still-undiagnosed cases, and to work towards causal treatment options that so far are available only for a few metabolic conditions. To meet these challenges, the research community needs highly efficient model systems. With an increasing number of relevant assays and rapidly developing novel methodologies, the fruit fly Drosophila melanogaster is ideally positioned to change gear in ID and ASD research. The aim of this Review is to summarize some of the exciting work that already has drawn attention to Drosophila as a model for these disorders. We highlight well-established ID- and ASD-relevant fly phenotypes at the (sub)cellular, brain and behavioral levels, and discuss strategies of how this extraordinarily efficient and versatile model can contribute to 'next generation' medical genomics and to a better understanding of these disorders.
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Affiliation(s)
- Mireia Coll-Tané
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Alina Krebbers
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Anna Castells-Nobau
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Christiane Zweier
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Annette Schenck
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
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23
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Molosh AI, Shekhar A. Neurofibromatosis type 1 as a model system to study molecular mechanisms of autism spectrum disorder symptoms. PROGRESS IN BRAIN RESEARCH 2018; 241:37-62. [PMID: 30447756 DOI: 10.1016/bs.pbr.2018.09.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Neurofibromatosis type 1 (NF1) is monogenic neurodevelopmental disorder caused by mutation of NF1 gene, which leads to increased susceptibility to various tumors formations. Additionally, majority of patients with NF1 are experience high incidence of cognitive deficits. Particularly, we review the growing number of reports demonstrated a higher incidence of autism spectrum disorder (ASD) in individuals with NF1. In this review we also discuss face validity of preclinical Nf1 mouse models. Then we describe discoveries from these animal models that have uncovered the deficiencies in the regulation of Ras and other intracellular pathways as critical mechanisms underlying the Nf1 cognitive problems. We also summarize and interpret recent preclinical and clinical studies that point toward potential pharmacological therapies for NF1 patients.
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Affiliation(s)
- Andrei I Molosh
- Department of Psychiatry, Institute of Psychiatric Research, IU School of Medicine, Indianapolis, IN, United States; Stark Neurosciences Research Institute, IU School of Medicine, Indianapolis, IN, United States.
| | - Anantha Shekhar
- Department of Psychiatry, Institute of Psychiatric Research, IU School of Medicine, Indianapolis, IN, United States; Stark Neurosciences Research Institute, IU School of Medicine, Indianapolis, IN, United States; Department of Pharmacology & Toxicology, IU School of Medicine, Indianapolis, IN, United States; Indiana Clinical and Translational Institute, IU School of Medicine, Indianapolis, IN, United States
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24
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Ormerod KG, Jung J, Mercier AJ. Modulation of neuromuscular synapses and contraction in Drosophila 3rd instar larvae. J Neurogenet 2018; 32:183-194. [PMID: 30303434 DOI: 10.1080/01677063.2018.1502761] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Over the past four decades, Drosophila melanogaster has become an increasingly important model system for studying the modulation of chemical synapses and muscle contraction by cotransmitters and neurohormones. This review describes how advantages provided by Drosophila have been utilized to investigate synaptic modulation, and it discusses key findings from investigations of cotransmitters and neurohormones that act on body wall muscles of 3rd instar Drosophila larvae. These studies have contributed much to our understanding of how neuromuscular systems are modulated by neuropeptides and biogenic amines, but there are still gaps in relating these peripheral modulatory effects to behavior.
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Affiliation(s)
- Kiel G Ormerod
- a Department of Biology , Massachusetts Institute of Technology , Cambridge , MA , USA
| | - JaeHwan Jung
- b Department of Biological Sciences , Brock University , St. Catharines , Canada
| | - A Joffre Mercier
- b Department of Biological Sciences , Brock University , St. Catharines , Canada
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25
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Physical interaction between neurofibromin and serotonin 5-HT6 receptor promotes receptor constitutive activity. Proc Natl Acad Sci U S A 2016; 113:12310-12315. [PMID: 27791021 DOI: 10.1073/pnas.1600914113] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Active G protein-coupled receptor (GPCR) conformations not only are promoted by agonists but also occur in their absence, leading to constitutive activity. Association of GPCRs with intracellular protein partners might be one of the mechanisms underlying GPCR constitutive activity. Here, we show that serotonin 5 hydroxytryptamine 6 (5-HT6) receptor constitutively activates the Gs/adenylyl cyclase pathway in various cell types, including neurons. Constitutive activity is strongly reduced by silencing expression of the Ras-GTPase activating protein (Ras-GAP) neurofibromin, a 5-HT6 receptor partner. Neurofibromin is a multidomain protein encoded by the NF1 gene, the mutation of which causes Neurofibromatosis type 1 (NF1), a genetic disorder characterized by multiple benign and malignant nervous system tumors and cognitive deficits. Disrupting association of 5-HT6 receptor with neurofibromin Pleckstrin Homology (PH) domain also inhibits receptor constitutive activity, and PH domain expression rescues 5-HT6 receptor-operated cAMP signaling in neurofibromin-deficient cells. Furthermore, PH domains carrying mutations identified in NF1 patients that prevent interaction with the 5-HT6 receptor fail to rescue receptor constitutive activity in neurofibromin-depleted cells. Further supporting a role of neurofibromin in agonist-independent Gs signaling elicited by native receptors, the phosphorylation of cAMP-responsive element-binding protein (CREB) is strongly decreased in prefrontal cortex of Nf1+/- mice compared with WT mice. Moreover, systemic administration of a 5-HT6 receptor inverse agonist reduces CREB phosphorylation in prefrontal cortex of WT mice but not Nf1+/- mice. Collectively, these findings suggest that disrupting 5-HT6 receptor-neurofibromin interaction prevents agonist-independent 5-HT6 receptor-operated cAMP signaling in prefrontal cortex, an effect that might underlie neuronal abnormalities in NF1 patients.
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26
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Rosenbaum T, Patrie KM, Ratner N. Neurofibromatosis Type 1: Genetic and Cellular Mechanisms of Peripheral Nerve Tumor Formation. Neuroscientist 2016. [DOI: 10.1177/107385849700300614] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Neurofibromatosis type 1 (NF1) is among the most common inherited human diseases. The NF1 protein is a Ras-GTPase activating protein, positioning NF1 in important intracellular signaling pathways. Patients with mutations in the NF1 gene can develop benign peripheral nerve tumors (neurofibromas), learning disabilities, and/or benign optic nerve gliomas, in addition to abnormalities unassociated with the nervous system. The NF1 gene is believed to act as a tumor suppressor. How NF1 mutations relate to benign features of NF1 is the subject of active investigation. Studies using transgenic mice with NF1 mutations and cells derived from these mice have yielded exciting new data, implicating multiple cell types mutant at NF1 and possibly factors in the environment in the pathogenesis of benign neurofibromas. NEUROSCIENTIST 3:412-420, 1997
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Affiliation(s)
| | - Kevin M. Patrie
- Department of Pediatrics Düsseldorf Department of Cell Biology, Neurobiology, and Anatomy, University of Cincinnati College of Medicine Cincinnati, Ohio
| | - Nancy Ratner
- Department of Pediatrics Düsseldorf Department of Cell Biology, Neurobiology, and Anatomy, University of Cincinnati College of Medicine Cincinnati, Ohio
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Sensitization of Ion Channels Contributes to Central and Peripheral Dysfunction in Neurofibromatosis Type 1. Mol Neurobiol 2016; 54:3342-3349. [PMID: 27167129 DOI: 10.1007/s12035-016-9907-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 05/03/2016] [Indexed: 12/13/2022]
Abstract
Neurofibromatosis type 1 (Nf1) is a progressive, autosomal disorder with a large degree of variability and severity of manifestations including neurological, cutaneous, ocular/orbital, orthopedic, and vascular abnormalities. Nearly half of Nf1 patients presents with cognitive impairment, specifically spatial learning deficits. These clinical manifestations suggest a global impairment of both central and peripheral nervous system functions in neurofibromatosis. Nf1 encodes for neurofibromin, a Ras GTPase-activating protein (Ras GAP) that has been implicated in the regulation of long-term potentiation (LTP), Ras/ERK (extracellular signal-regulated kinase) signaling, and learning in mice. Over the last decades, mice with a targeted mutation in the Nf1 gene, Nf1 -/- chimeric mice, Nf1 exon-specific knockout mice, and mice with tissue-specific inactivation of Nf1 have been generated to model the human Nf1 disease. These studies have implicated neurofibromin in regulation of the release of the inhibitory neurotransmitter γ-amino butyric acid (GABA) in the hippocampus and frontal lobe, which can regulate memory. Mutations in neurofibromin thus lead to perturbed ERK signaling, which alters GABA release, LTP, and subsequently leads to learning deficits. In addition to these cognitive deficits, Nf1 patients also have defects in fine and gross motor coordination as well as decreased muscle strength. Although the mechanisms underlying these motor deficits are unknown, deficits in GABAergic neurotransmission in both the motor cortex and cerebellum have been suggested. In this review, we present evidence to support the hypothesis that alterations of ion channel activity in Nf1 underscore the dysregulated neuronal communication in non-neuronal and neuronal cells that likely contributes to the clinical cornucopia of Nf1.
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Hu HT, Shih PY, Shih YT, Hsueh YP. The Involvement of Neuron-Specific Factors in Dendritic Spinogenesis: Molecular Regulation and Association with Neurological Disorders. Neural Plast 2015; 2016:5136286. [PMID: 26819769 PMCID: PMC4706964 DOI: 10.1155/2016/5136286] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 07/26/2015] [Indexed: 12/26/2022] Open
Abstract
Dendritic spines are the location of excitatory synapses in the mammalian nervous system and are neuron-specific subcellular structures essential for neural circuitry and function. Dendritic spine morphology is determined by the F-actin cytoskeleton. F-actin remodeling must coordinate with different stages of dendritic spinogenesis, starting from dendritic filopodia formation to the filopodia-spines transition and dendritic spine maturation and maintenance. Hundreds of genes, including F-actin cytoskeleton regulators, membrane proteins, adaptor proteins, and signaling molecules, are known to be involved in regulating synapse formation. Many of these genes are not neuron-specific, but how they specifically control dendritic spine formation in neurons is an intriguing question. Here, we summarize how ubiquitously expressed genes, including syndecan-2, NF1 (encoding neurofibromin protein), VCP, and CASK, and the neuron-specific gene CTTNBP2 coordinate with neurotransmission, transsynaptic signaling, and cytoskeleton rearrangement to control dendritic filopodia formation, filopodia-spines transition, and dendritic spine maturation and maintenance. The aforementioned genes have been associated with neurological disorders, such as autism spectrum disorders (ASDs), mental retardation, learning difficulty, and frontotemporal dementia. We also summarize the corresponding disorders in this report.
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Affiliation(s)
- Hsiao-Tang Hu
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Pu-Yun Shih
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Yu-Tzu Shih
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Yi-Ping Hsueh
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
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Yzaguirre AD, Padmanabhan A, de Groh ED, Engleka KA, Li J, Speck NA, Epstein JA. Loss of neurofibromin Ras-GAP activity enhances the formation of cardiac blood islands in murine embryos. eLife 2015; 4:e07780. [PMID: 26460546 PMCID: PMC4714971 DOI: 10.7554/elife.07780] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 10/12/2015] [Indexed: 12/15/2022] Open
Abstract
Type I neurofibromatosis (NF1) is caused by mutations in the NF1 gene encoding neurofibromin. Neurofibromin exhibits Ras GTPase activating protein (Ras-GAP) activity that is thought to mediate cellular functions relevant to disease phenotypes. Loss of murine Nf1 results in embryonic lethality due to heart defects, while mice with monoallelic loss of function mutations or with tissue-specific inactivation have been used to model NF1. Here, we characterize previously unappreciated phenotypes in Nf1-/- embryos, which are inhibition of hemogenic endothelial specification in the dorsal aorta, enhanced yolk sac hematopoiesis, and exuberant cardiac blood island formation. We show that a missense mutation engineered into the active site of the Ras-GAP domain is sufficient to reproduce ectopic blood island formation, cardiac defects, and overgrowth of neural crest-derived structures seen in Nf1-/-embryos. These findings demonstrate a role for Ras-GAP activity in suppressing the hemogenic potential of the heart and restricting growth of neural crest-derived tissues. DOI:http://dx.doi.org/10.7554/eLife.07780.001 Messages are carried from the surface of a cell to the cell’s nucleus in order to regulate various processes such as how often the cell will divide. The Ras-signaling pathway carries some of these messages. A gene called Nf1 encodes a protein in this pathway that deactivates another protein called Ras when the message is no longer required. If a mutation in Nf1 prevents it from deactivating Ras, the pathway becomes hyperactivated. In humans, this results in a disorder called Neurofibromatosis type I, which is characterized by tumors that affect many parts of the body. When the expression of Nf1 is turned off in mice, the mice die as embryos because of cardiac defects. But a mouse in which Nf1 has been turned off in specific organs or tissues other than the heart can survive, and these mice are used to model Neurofibromatosis type I and to help to identify potential treatments. Yzaguirre et al. have now identified new roles for Nf1 during embryonic development. In the embryo, blood cells originate from the cells lining the blood vessels. The experiments revealed that, when the Nf1 gene was mutated in mice, fewer blood cells formed from the lining of the major blood vessel that leaves the embryonic heart. In contrast, these mutant mice formed more structures called cardiac blood islands than a normal mouse. These structures line the heart, and have the potential to generate new blood cells for the heart to pump. These results shed new light on how blood is originally formed from the lining of the heart and blood vessels, and show that Ras signaling must be tightly regulated to maintain normal blood development in the embryo. Furthermore, Yzaguirre et al. demonstrated that this excessive formation of cardiac blood islands resulted specifically from the loss of Nf1’s role in the Ras-signaling pathway. This was achieved by using gene targeting to generate a mouse that expresses Nf1 with a minor change that affects only the protein’s interaction with Ras. In the future, this new strain of mouse will be a useful tool in determining if specific aspects of Neurofibromatosis type I can be attributed to loss of Nf1’s role in Ras-signaling and could therefore be treated by medicines that target this pathway. DOI:http://dx.doi.org/10.7554/eLife.07780.002
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Affiliation(s)
- Amanda D Yzaguirre
- Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States.,Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States
| | - Arun Padmanabhan
- Institute for Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States.,Cardiovascular Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States
| | - Eric D de Groh
- Institute for Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States.,Cardiovascular Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States
| | - Kurt A Engleka
- Institute for Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States.,Cardiovascular Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States
| | - Jun Li
- Institute for Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States.,Cardiovascular Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States
| | - Nancy A Speck
- Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States.,Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States
| | - Jonathan A Epstein
- Institute for Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States.,Cardiovascular Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States
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Ratner N, Miller SJ. A RASopathy gene commonly mutated in cancer: the neurofibromatosis type 1 tumour suppressor. Nat Rev Cancer 2015; 15:290-301. [PMID: 25877329 PMCID: PMC4822336 DOI: 10.1038/nrc3911] [Citation(s) in RCA: 300] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Neurofibromatosis type 1 (NF1) is a common genetic disorder that predisposes affected individuals to tumours. The NF1 gene encodes a RAS GTPase-activating protein called neurofibromin and is one of several genes that (when mutant) affect RAS-MAPK signalling, causing related diseases collectively known as RASopathies. Several RASopathies, beyond NF1, are cancer predisposition syndromes. Somatic NF1 mutations also occur in 5-10% of human sporadic cancers and may contribute to resistance to therapy. To highlight areas for investigation in RASopathies and sporadic tumours with NF1 mutations, we summarize current knowledge of NF1 disease, the NF1 gene and neurofibromin, neurofibromin signalling pathways and recent developments in NF1 therapeutics.
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Affiliation(s)
- Nancy Ratner
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital, 3333 Burnet Avenue, Cincinnati, Ohio 45229, USA
| | - Shyra J Miller
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital, 3333 Burnet Avenue, Cincinnati, Ohio 45229, USA
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Wolman MA, de Groh ED, McBride SM, Jongens TA, Granato M, Epstein JA. Modulation of cAMP and ras signaling pathways improves distinct behavioral deficits in a zebrafish model of neurofibromatosis type 1. Cell Rep 2014; 8:1265-70. [PMID: 25176649 PMCID: PMC5850931 DOI: 10.1016/j.celrep.2014.07.054] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 07/20/2014] [Accepted: 07/29/2014] [Indexed: 12/19/2022] Open
Abstract
Neurofibromatosis type 1 (NF1) is a common autosomal-dominant disorder associated with attention deficits and learning disabilities. The primary known function of neurofibromin, encoded by the NF1 gene, is to downregulate Ras activity. We show that nf1-deficient zebrafish exhibit learning and memory deficits and that acute pharmacological inhibition of downstream targets of Ras (MAPK and PI3K) restores memory consolidation and recall but not learning. Conversely, acute pharmacological enhancement of cAMP signaling restores learning but not memory. Our data provide compelling evidence that neurofibromin regulates learning and memory by distinct molecular pathways in vertebrates and that deficits produced by genetic loss of function are reversible. These findings support the investigation of cAMP signaling enhancers as a companion therapy to Ras inhibition in the treatment of cognitive dysfunction in NF1.
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Affiliation(s)
- Marc A Wolman
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Eric D de Groh
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sean M McBride
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Thomas A Jongens
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael Granato
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jonathan A Epstein
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Schwetye KE, Gutmann DH. Cognitive and behavioral problems in children with neurofibromatosis type 1: challenges and future directions. Expert Rev Neurother 2014; 14:1139-52. [PMID: 25161109 DOI: 10.1586/14737175.2014.953931] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cognitive and behavioral disorders affect nearly 80% of all children with the neurofibromatosis type 1 inherited cancer syndrome, and are among the most significant clinical manifestations for patients and their families. One of the barriers to successful therapeutic intervention is the wide spectrum of clinical phenotypic expression, ranging from visuospatial learning problems to social perceptual deficits (autism). Leveraging numerous small-animal models of neurofibromatosis type 1, several promising targets have been identified to treat the learning, attention, and autism spectrum phenotypes in this at-risk population. In this review, we provide an up-to-date summary of our current understanding of these disorders in NF1, and propose future research directions aimed at designing more effective therapeutic approaches and clinical trials.
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Affiliation(s)
- Katherine E Schwetye
- Department of Pathology, Division of Neuropathology, Washington University School of Medicine, Box 8111, 660 S. Euclid Avenue, St. Louis MO 63110, USA
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Anastasaki C, Gutmann DH. Neuronal NF1/RAS regulation of cyclic AMP requires atypical PKC activation. Hum Mol Genet 2014; 23:6712-21. [PMID: 25070947 DOI: 10.1093/hmg/ddu389] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Neurofibromatosis type 1 (NF1) is a common neurodevelopmental disorder in which affected individuals are prone to learning, attention and behavioral problems. Previous studies in mice and flies have yielded conflicting results regarding the specific effector pathways responsible for NF1 protein (neurofibromin) regulation of neuronal function, with both cyclic AMP (cAMP)- and RAS-dependent mechanisms described. Herein, we leverage a combination of induced pluripotent stem cell-derived NF1 patient neural progenitor cells and Nf1 genetically engineered mice to establish, for the first time, that neurofibromin regulation of cAMP requires RAS activation in human and mouse neurons. However, instead of involving RAS-mediated MEK/AKT signaling, RAS regulation of cAMP homeostasis operates through the activation of atypical protein kinase C zeta, leading to GRK2-driven Gαs inactivation. These findings reveal a novel mechanism by which RAS can regulate cAMP levels in the mammalian brain.
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Affiliation(s)
- Corina Anastasaki
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - David H Gutmann
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
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Abstract
In dendritic spines, Ras plays a critical role in synaptic plasticity but its regulation mechanism is not fully understood. Here, using a fluorescence resonance energy transfer/fluorescence lifetime imaging microscopy-based Ras imaging technique in combination with 2-photon glutamate uncaging, we show that neurofibromin, in which loss-of-function mutations cause Neurofibromatosis Type 1 (NF1), contributes to the majority (∼90%) of Ras inactivation in dendritic spines of pyramidal neurons in the CA1 region of the rat hippocampus. Loss of neurofibromin causes sustained Ras activation in spines, which leads to impairment of spine structural plasticity and loss of spines in an activity-dependent manner. Therefore, deregulation of postsynaptic Ras signaling may explain, at least in part, learning disabilities associated with NF1.
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35
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Walker JA, Bernards A. A Drosophila screen identifies neurofibromatosis-1 genetic modifiers involved in systemic and synaptic growth. Rare Dis 2014; 2:e28341. [PMID: 25054093 PMCID: PMC4091572 DOI: 10.4161/rdis.28341] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 02/12/2014] [Accepted: 02/24/2014] [Indexed: 11/19/2022] Open
Abstract
Neurofibromatosis type 1 (NF1) is caused by loss of a negative regulator of Ras oncoproteins. Unknown genetic modifiers have been implicated in NF1's characteristic variability. Drosophila melanogaster dNf1 phenotypes include cognitive deficits and reduced growth, both of which resemble human symptoms. We recently reported results of a screen for dominant modifiers of dNf1 growth. Suppressors include the dAlk tyrosine kinase and its activating ligand, two other genes involved in Ras/ERK signal transduction, the synaptic scaffold Dap160 and the CCKLR-17D1 drosulfakinin receptor. Additional modifiers include several genes involved in cAMP/PKA signaling. Providing mechanistic insights, dAlk, jeb, and CCKLR-17D1 also suppress a dNf1 synaptic overgrowth defect, and increasing cAMP/PKA signaling in the neuroendocrine ring gland rescued the dNf1 growth deficiency. Finally, among the several suppressors identified in our screen, we specifically implicate ALK as a potential therapeutic target by showing that NF1-regulated ALK/RAS/ERK signaling is conserved in human cells.
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Affiliation(s)
- James A Walker
- Massachusetts General Hospital Center for Cancer Research and Harvard Medical School; Charlestown, MA USA ; Center for Human Genetic Research; Massachusetts General Hospital; Boston, MA USA
| | - André Bernards
- Massachusetts General Hospital Center for Cancer Research and Harvard Medical School; Charlestown, MA USA ; Center for Human Genetic Research; Massachusetts General Hospital; Boston, MA USA
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36
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Neurofibromatosis type I. Mol Oncol 2013. [DOI: 10.1017/cbo9781139046947.061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Genetic and functional studies implicate synaptic overgrowth and ring gland cAMP/PKA signaling defects in the Drosophila melanogaster neurofibromatosis-1 growth deficiency. PLoS Genet 2013; 9:e1003958. [PMID: 24278035 PMCID: PMC3836801 DOI: 10.1371/journal.pgen.1003958] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 10/01/2013] [Indexed: 12/21/2022] Open
Abstract
Neurofibromatosis type 1 (NF1), a genetic disease that affects 1 in 3,000, is caused by loss of a large evolutionary conserved protein that serves as a GTPase Activating Protein (GAP) for Ras. Among Drosophila melanogaster Nf1 (dNf1) null mutant phenotypes, learning/memory deficits and reduced overall growth resemble human NF1 symptoms. These and other dNf1 defects are relatively insensitive to manipulations that reduce Ras signaling strength but are suppressed by increasing signaling through the 3′-5′ cyclic adenosine monophosphate (cAMP) dependent Protein Kinase A (PKA) pathway, or phenocopied by inhibiting this pathway. However, whether dNf1 affects cAMP/PKA signaling directly or indirectly remains controversial. To shed light on this issue we screened 486 1st and 2nd chromosome deficiencies that uncover >80% of annotated genes for dominant modifiers of the dNf1 pupal size defect, identifying responsible genes in crosses with mutant alleles or by tissue-specific RNA interference (RNAi) knockdown. Validating the screen, identified suppressors include the previously implicated dAlk tyrosine kinase, its activating ligand jelly belly (jeb), two other genes involved in Ras/ERK signal transduction and several involved in cAMP/PKA signaling. Novel modifiers that implicate synaptic defects in the dNf1 growth deficiency include the intersectin-related synaptic scaffold protein Dap160 and the cholecystokinin receptor-related CCKLR-17D1 drosulfakinin receptor. Providing mechanistic clues, we show that dAlk, jeb and CCKLR-17D1 are among mutants that also suppress a recently identified dNf1 neuromuscular junction (NMJ) overgrowth phenotype and that manipulations that increase cAMP/PKA signaling in adipokinetic hormone (AKH)-producing cells at the base of the neuroendocrine ring gland restore the dNf1 growth deficiency. Finally, supporting our previous contention that ALK might be a therapeutic target in NF1, we report that human ALK is expressed in cells that give rise to NF1 tumors and that NF1 regulated ALK/RAS/ERK signaling appears conserved in man. Neurofibromatosis type 1 (NF1) is a genetic disease that affects 1 in 3,000 and that is caused by loss of a protein that inactivates Ras oncoproteins. NF1 is a characteristically variable disease that predisposes patients to several symptoms, the most common of which include benign and malignant tumors, reduced growth and learning problems. We and others previously found that fruit fly mutants that lack a highly conserved dNf1 gene are reduced in size and exhibit impaired learning and memory, and that both defects appear due to abnormal Ras and cyclic-AMP (cAMP) signaling. The former was unremarkable, but how loss of dNf1 affects cAMP signaling remains poorly understood. Here we report results of a genetic screen for dominant modifiers of the dNf1 growth defect. This screen and follow-up functional studies support a model in which synaptic defects and reduced cAMP signaling in specific parts of the neuroendocrine ring gland contribute to the dNf1 growth defect. Beyond these results, we show that human ALK is expressed in cells that give rise to NF1 tumors, and that NF1 regulated ALK/RAS/ERK signaling is evolutionary conserved.
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Neurofibromin mediates FAK signaling in confining synapse growth at Drosophila neuromuscular junctions. J Neurosci 2013; 32:16971-81. [PMID: 23175848 DOI: 10.1523/jneurosci.1756-12.2012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Neurofibromatosis type I (NF1), caused by the mutation in the NF1 gene, is characterized by multiple pathological symptoms. Importantly, ~50% of NF1 patients also suffer learning difficulty. Although downstream pathways are well studied, regulation of the NF1-encoded neurofibromin protein is less clear. Here, we focused on the pathophysiology of Drosophila NF1 mutants in synaptic growth at neuromuscular junctions. Our analysis suggests that the Drosophila neurofibromin protein NF1 is required to constrain synaptic growth and transmission. NF1 functions downstream of the Drosophila focal adhesion kinase (FAK) Fak56 and physically interacts with Fak56. The N-terminal region of NF1 mediates the interaction with Fak56 and is required for the signaling activity and presynaptic localization of NF1. In presynapses, NF1 acts via the cAMP pathway, but independent of its GAP activity, to restrain synaptic growth. Thus, presynaptic FAK signaling may be disrupted, causing abnormal synaptic growth and transmission in the NF1 genetic disorder.
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Diggs-Andrews KA, Gutmann DH. Modeling cognitive dysfunction in neurofibromatosis-1. Trends Neurosci 2013; 36:237-47. [PMID: 23312374 DOI: 10.1016/j.tins.2012.12.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 11/19/2012] [Accepted: 12/12/2012] [Indexed: 12/17/2022]
Abstract
Cognitive dysfunction, including significant impairments in learning, behavior, and attention, is found in over 10% of children in the general population. However, in the common inherited cancer predisposition syndrome, neurofibromatosis type 1 (NF1), the prevalence of these cognitive deficits approaches 70%. As a monogenic disorder, NF1 provides a unique genetic tool to identify and dissect mechanistically the molecular and cellular bases underlying cognitive dysfunction. In this review, we discuss Nf1 fly and mouse systems that mimic many of the cognitive abnormalities seen in children with NF1. Further, we describe discoveries from these models that have uncovered defects in the regulation of Ras activity, cAMP generation, and dopamine homeostasis as key mechanisms important for cognitive dysfunction in children with NF1.
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Affiliation(s)
- Kelly A Diggs-Andrews
- Department of Neurology, Washington University School of Medicine, Box 8111, 660 South Euclid Avenue, St. Louis, MO 63110, USA
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40
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Abstract
Neurofibromatosis 1 (NF1) is an inherited neurocutaneous disease that has a major impact on the nervous system, eye, skin, and bone. Individuals with NF1 have a predisposition to benign and malignant tumor formation and the hallmark lesion is the neurofibroma, a benign peripheral nerve sheath tumor. The gene for NF1 was cloned on chromosome 17q11.2 and neurofibromin, the NF1 protein, controls cell growth and proliferation by regulating the proto-oncogene Ras and cyclic adenosine monophosphate (AMP). Advances in molecular biology and mouse models of disease have enhanced our understanding of the pathogenesis of NF1 complications and facilitated targeted therapy. Progress has been made in developing robust clinical and radiological outcome measures and clinical trials are underway for children with learning difficulties and for individuals with symptomatic plexiform neurofibromas.
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Vallée B, Doudeau M, Godin F, Gombault A, Tchalikian A, de Tauzia ML, Bénédetti H. Nf1 RasGAP inhibition of LIMK2 mediates a new cross-talk between Ras and Rho pathways. PLoS One 2012; 7:e47283. [PMID: 23082153 PMCID: PMC3474823 DOI: 10.1371/journal.pone.0047283] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 09/13/2012] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Ras GTPases mediate numerous biological processes through their ability to cycle between an inactive GDP-bound form and an active GTP-bound form. Guanine nucleotide exchange factors (GEFs) favor the formation of the active Ras-GTP, whereas GTPase activating proteins (GAPs) promote the formation of inactive Ras-GDP. Numerous studies have established complex signaling cross-talks between Ras GTPases and other members of the superfamily of small GTPases. GEFs were thought to play a major role in these cross-talks. However, recently GAPs were also shown to play crucial roles in these processes. Among RasGAPs, Nf1 is of special interest. Nf1 is responsible for the genetic disease Neurofibromatosis type I, and recent data strongly suggest that this RasGAP connects different signaling pathways. METHODOLOGY/PRINCIPAL FINDINGS In order to know if the RasGAP Nf1 might play a role in connecting Ras GTPases to other small GTPase pathways, we systematically looked for new partners of Nf1, by performing a yeast two-hybrid screening on its SecPH domain. LIMK2, a major kinase of the Rho/ROCK/LIMK2/cofilin pathway, was identified in this screening. We confirmed this interaction by co-immunoprecipitation experiments, and further characterized it. We also demonstrated its specificity: the close related homolog of LIMK2, LIMK1, does not interact with the SecPH domain of Nf1. We then showed that SecPH partially inhibits the kinase activity of LIMK2 on cofilin. Our results furthermore suggest a precise mechanism for this inhibition: in fact, SecPH would specifically prevent LIMK2 activation by ROCK, its upstream regulator. CONCLUSIONS/SIGNIFICANCE Although previous data had already connected Nf1 to actin cytoskeleton dynamics, our study provides for the first time possible detailed molecular requirements of this involvement. Nf1/LIMK2 interaction and inhibition allows to directly connect neurofibromatosis type I to actin cytoskeleton remodeling, and provides evidence that the RasGAP Nf1 mediates a new cross-talk between Ras and Rho signaling pathways within the superfamily of small GTPases.
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Affiliation(s)
- Béatrice Vallée
- Centre de Biophysique Moléculaire, Centre Nationale de la Recherche Scientifique (CNRS), University of Orléans and Institut National de la Santé et de la Recherche Médicale (INSERM), Orléans, France
| | - Michel Doudeau
- Centre de Biophysique Moléculaire, Centre Nationale de la Recherche Scientifique (CNRS), University of Orléans and Institut National de la Santé et de la Recherche Médicale (INSERM), Orléans, France
| | - Fabienne Godin
- Centre de Biophysique Moléculaire, Centre Nationale de la Recherche Scientifique (CNRS), University of Orléans and Institut National de la Santé et de la Recherche Médicale (INSERM), Orléans, France
| | | | | | | | - Hélène Bénédetti
- Centre de Biophysique Moléculaire, Centre Nationale de la Recherche Scientifique (CNRS), University of Orléans and Institut National de la Santé et de la Recherche Médicale (INSERM), Orléans, France
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42
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Okray Z, Hassan BA. Genetic approaches in Drosophila for the study neurodevelopmental disorders. Neuropharmacology 2012; 68:150-6. [PMID: 23067575 DOI: 10.1016/j.neuropharm.2012.09.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 08/31/2012] [Accepted: 09/07/2012] [Indexed: 12/16/2022]
Abstract
The fruit fly Drosophila melanogaster is one of the premier genetic model organisms used in biomedical research today owing to the extraordinary power of its genetic tool-kit. Made famous by numerous seminal discoveries of basic developmental mechanisms and behavioral genetics, the power of fruit fly genetics is becoming increasingly applied to questions directly relevant to human health. In this review we discuss how Drosophila research is applied to address major questions in neurodevelopmental disorders. This article is part of the Special Issue entitled 'Neurodevelopmental Disorders'.
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Affiliation(s)
- Zeynep Okray
- Laboratory of Neurogenetics, VIB Center for the Biology of Disease, VIB, Herestraat 49, Leuven, Belgium
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43
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Hsueh YP. From neurodevelopment to neurodegeneration: the interaction of neurofibromin and valosin-containing protein/p97 in regulation of dendritic spine formation. J Biomed Sci 2012; 19:33. [PMID: 22449146 PMCID: PMC3326706 DOI: 10.1186/1423-0127-19-33] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2012] [Accepted: 03/26/2012] [Indexed: 12/22/2022] Open
Abstract
Both Neurofibromatosis type I (NF1) and inclusion body myopathy with Paget's disease of bone and frontotemporal dementia (IBMPFD) are autosomal dominant genetic disorders. These two diseases are fully penetrant but with high heterogeneity in phenotypes, suggesting the involvement of genetic modifiers in modulating patients' phenotypes. Although NF1 is recognized as a developmental disorder and IBMPFD is associated with degeneration of multiple tissues, a recent study discovered the direct protein interaction between neurofibromin, the protein product of the NF1 gene, and VCP/p97, encoded by the causative gene of IBMPFD. Both NF1 and VCP/p97 are critical for dendritic spine formation, which provides the cellular mechanism explaining the cognitive deficits and dementia found in patients. Moreover, disruption of the interaction between neurofibromin and VCP impairs dendritic spinogenesis. Neurofibromin likely influences multiple downstream pathways to control dendritic spinogenesis. One is to activate the protein kinase A pathway to initiate dendritic spine formation; another is to regulate the synaptic distribution of VCP and control the activity of VCP in dendritic spinogenesis. Since neurofibromin and VCP/p97 also regulate cell growth and bone metabolism, the understanding of neurofibromin and VCP/p97 in neurons may be applied to study of cancer and bone. Statin treatment rescues the spine defects caused by VCP deficiency, suggesting the potential role of statin in clinical treatment for these two diseases.
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Affiliation(s)
- Yi-Ping Hsueh
- Institute of Molecular Biology, Academia Sinica, 128, Sec 2, Academia Rd, Taipei 11529, Taiwan.
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44
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A fraction of neurofibromin interacts with PML bodies in the nucleus of the CCF astrocytoma cell line. Biochem Biophys Res Commun 2012; 418:689-94. [DOI: 10.1016/j.bbrc.2012.01.079] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 01/14/2012] [Indexed: 02/07/2023]
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Gouzi JY, Moressis A, Walker JA, Apostolopoulou AA, Palmer RH, Bernards A, Skoulakis EMC. The receptor tyrosine kinase Alk controls neurofibromin functions in Drosophila growth and learning. PLoS Genet 2011; 7:e1002281. [PMID: 21949657 PMCID: PMC3174217 DOI: 10.1371/journal.pgen.1002281] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 07/18/2011] [Indexed: 11/19/2022] Open
Abstract
Anaplastic Lymphoma Kinase (Alk) is a Receptor Tyrosine Kinase (RTK) activated in several cancers, but with largely unknown physiological functions. We report two unexpected roles for the Drosophila ortholog dAlk, in body size determination and associative learning. Remarkably, reducing neuronal dAlk activity increased body size and enhanced associative learning, suggesting that its activation is inhibitory in both processes. Consistently, dAlk activation reduced body size and caused learning deficits resembling phenotypes of null mutations in dNf1, the Ras GTPase Activating Protein-encoding conserved ortholog of the Neurofibromatosis type 1 (NF1) disease gene. We show that dAlk and dNf1 co-localize extensively and interact functionally in the nervous system. Importantly, genetic or pharmacological inhibition of dAlk rescued the reduced body size, adult learning deficits, and Extracellular-Regulated-Kinase (ERK) overactivation dNf1 mutant phenotypes. These results identify dAlk as an upstream activator of dNf1-regulated Ras signaling responsible for several dNf1 defects, and they implicate human Alk as a potential therapeutic target in NF1. Neurofibromatosis-1 (NF1) syndrome is a common (1/3,000 births) genetic disorder affecting multiple organ systems, including the nervous system. Its clinical features include short stature, learning disabilities, and several types of benign and malignant tumors. NF1 is caused by mutations that inactivate the NF1 gene, a crucial negative regulator of Ras signaling. Although unregulated Ras signaling is a hallmark of NF1, the specific Ras signaling pathways responsible for disease development remain largely unknown. The Drosophila and human Nf1 genes are highly conserved; and, as in patients, mutant flies are smaller than usual and present deficient learning. Here, we identified the Drosophila Receptor Tyrosine Kinase dAlk as a negative regulator of organismal growth and olfactory learning. We show that excessive dAlk activation results in growth and learning defects similar to those of Nf1 mutants. Genetic suppression studies and pharmacological inhibition indicate dAlk as a critical upstream activator of Nf1-regulated neuronal Ras/ERK signals that contribute to size determination and learning. Importantly, our results strongly suggest that Alk represents a novel, highly specific, and promising therapeutic target in human NF1.
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Affiliation(s)
- Jean Y. Gouzi
- Institute of Cellular and Developmental Biology, Biomedical Sciences Research Centre "Alexander Fleming," Vari, Greece
| | - Anastasios Moressis
- Institute of Cellular and Developmental Biology, Biomedical Sciences Research Centre "Alexander Fleming," Vari, Greece
- Department of Basic Sciences, School of Health Sciences, National and Kapodistrian University of Athens, Athens, Greece
| | - James A. Walker
- Center for Cancer Research, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Anthi A. Apostolopoulou
- Institute of Cellular and Developmental Biology, Biomedical Sciences Research Centre "Alexander Fleming," Vari, Greece
| | - Ruth H. Palmer
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - André Bernards
- Center for Cancer Research, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Efthimios M. C. Skoulakis
- Institute of Cellular and Developmental Biology, Biomedical Sciences Research Centre "Alexander Fleming," Vari, Greece
- * E-mail:
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46
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Lo-Castro A, D'Agati E, Curatolo P. ADHD and genetic syndromes. Brain Dev 2011; 33:456-61. [PMID: 20573461 DOI: 10.1016/j.braindev.2010.05.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2010] [Revised: 05/26/2010] [Accepted: 05/27/2010] [Indexed: 11/28/2022]
Abstract
A high rate of Attention Deficit/Hyperactivity Disorder (ADHD)-like characteristics has been reported in a wide variety of disorders including syndromes with known genetic causes. In this article, we review the genetic and the neurobiological links between ADHD symptoms and some genetic syndromes such as: Fragile X Syndrome, Neurofibromatosis 1, DiGeorge Syndrome, Tuberous Sclerosis Complex, Turner Syndrome, Williams Syndrome and Klinefelter Syndrome. Although each syndrome may arise from different genetic abnormalities with multiple molecular functions, the effects of these abnormalities may give rise to common effects downstream in the biological pathways or neural circuits, resulting in the presentation of ADHD symptoms. Early diagnosis of ADHD allows for earlier treatment, and has the potential for a better outcome in children with genetic syndromes.
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Affiliation(s)
- Adriana Lo-Castro
- Department of Neuroscience, Paediatric Neurology Unit, "Tor Vergata" University of Rome, Italy.
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Gatto CL, Broadie K. Drosophila modeling of heritable neurodevelopmental disorders. Curr Opin Neurobiol 2011; 21:834-41. [PMID: 21596554 DOI: 10.1016/j.conb.2011.04.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 04/08/2011] [Accepted: 04/25/2011] [Indexed: 11/16/2022]
Abstract
Heritable neurodevelopmental disorders are multifaceted disease conditions encompassing a wide range of symptoms including intellectual disability, cognitive dysfunction, autism and myriad other behavioral impairments. In cases where single, causative genetic defects have been identified, such as Angelman syndrome, Rett syndrome, Neurofibromatosis Type 1 and Fragile X syndrome, the classical Drosophila genetic system has provided fruitful disease models. Recent Drosophila studies have advanced our understanding of UBE3A, MECP2, NF1 and FMR1 function, respectively, in genetic, biochemical, anatomical, physiological and behavioral contexts. Investigations in Drosophila continue to provide the essential mechanistic understanding required to facilitate the conception of rational therapeutic treatments.
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Affiliation(s)
- Cheryl L Gatto
- Departments of Biological Sciences and Cell and Developmental Biology, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37232, USA
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Carbe C, Zhang X. Lens induction requires attenuation of ERK signaling by Nf1. Hum Mol Genet 2011; 20:1315-23. [PMID: 21233129 DOI: 10.1093/hmg/ddr014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Aphakia (lack of lens) is a rare human congenital disorder with its genetic etiology largely unknown. Even in model organisms, very few mutations are known to result in such a drastic ocular defect. In this study, we have shown that homozygous deletion of Nf1, the Ras GTPase gene underlying human neurofibromatosis type 1 syndrome, causes lens dysgenesis in mouse. Although early lens specification proceeded normally in Nf1 mutants, lens induction was disrupted due to deficient cell proliferation. Further analysis showed that extracellular signal-regulated kinase (ERK) signaling was initially elevated in the invaginating lens placode, but by the lens vesicle stage, ERK phosphorylation was significantly reduced. Only after intraperitoneal treatment of U0126, an inhibitor of ERK phosphorylation, was lens development restored in Nf1 mutants. Hyperactive Ras-mitogen-activated protein kinase (MAPK) signaling is known to cause neuro-cardiofacial-cutaneous (NCFC) syndromes in humans. As a member of NCFC family genes, Nf1 represents the first example that attenuation of Ras-MAPK kinase signaling pathway is essential for normal lens development.
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Affiliation(s)
- Christian Carbe
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Kahsai L, Zars T. Learning and memory in Drosophila: behavior, genetics, and neural systems. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2011; 99:139-67. [PMID: 21906539 DOI: 10.1016/b978-0-12-387003-2.00006-9] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The rich behavioral repertoire that Drosophila use to navigate in their natural environment suggests that flies can use memories to inform decisions. Development of paradigms to examine memories that restrict behavioral choice was essential in furthering our understanding of the genetics and neural systems of memory formation in the fly. Olfactory, visual, and place memory paradigms have proven influential in determining principles for the mechanisms of memory formation. Several parts of the nervous system have been shown to be important for different types of memories, including the mushroom bodies and the central complex. Thus far, about 40 genes have been linked to normal olfactory short-term memory. A subset of these genes have also been tested for a role in visual and place memory. Some genes have a common function in memory formation, specificity of action comes from where in the nervous system these genes act. Alternatively, some genes have a more restricted role in different types of memories.
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Affiliation(s)
- Lily Kahsai
- University of Missouri, Division of Biological Sciences, 114 Lefevre Hall, Columbia, MO 65211, USA
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50
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Abstract
A growing and interdisciplinary translational neuroscience research effort for neurodevelopmental disorders (NDDs) is investigating the mechanisms of dysfunction and testing effective treatment strategies in animal models and, when possible, in the clinic. NDDs with a genetic basis have received particular attention. Transgenic animals that mimic genetic insults responsible for disease in man have provided insight about mechanisms of dysfunction, and, surprisingly, have shown that cognitive deficits can be addressed in adult animals. This review will present recent translational research based on animal models of genetic NDDs, as well as pharmacotherapeutic strategies under development to address deficits of brain function for Down syndrome, fragile X syndrome, Rett syndrome, neurofibromatosis-1, tuberous sclerosis, and autism. Although these disorders vary in underlying causes and clinical presentation, common pathways and mechanisms for dysfunction have been observed. These include abnormal gene dosage, imbalance among neurotransmitter systems, and deficits in the development, maintenance and plasticity of neuronal circuits. NDDs affect multiple brain systems and behaviors that may be amenable to drug therapies that target distinct deficits. A primary goal of translational research is to replace symptomatic and supportive drug therapies with pharmacotherapies based on a principled understanding of the causes of dysfunction. Based on this principle, several recently developed therapeutic strategies offer clear promise for clinical development in man.
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