1
|
Lee H, Boor SA, Hilbert ZA, Meisel JD, Park J, Wang Y, McKeown R, Fischer SEJ, Andersen EC, Kim DH. Genetic variants that modify neuroendocrine gene expression and foraging behavior of C. elegans. SCIENCE ADVANCES 2024; 10:eadk9481. [PMID: 38865452 PMCID: PMC11168454 DOI: 10.1126/sciadv.adk9481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 04/30/2024] [Indexed: 06/14/2024]
Abstract
The molecular mechanisms underlying diversity in animal behavior are not well understood. A major experimental challenge is determining the contribution of genetic variants that affect neuronal gene expression to differences in behavioral traits. In Caenorhabditis elegans, the neuroendocrine transforming growth factor-β ligand, DAF-7, regulates diverse behavioral responses to bacterial food and pathogens. The dynamic neuron-specific expression of daf-7 is modulated by environmental and endogenous bacteria-derived cues. Here, we investigated natural variation in the expression of daf-7 from the ASJ pair of chemosensory neurons. We identified common genetic variants in gap-2, encoding a Ras guanosine triphosphatase (GTPase)-activating protein homologous to mammalian synaptic Ras GTPase-activating protein, which modify daf-7 expression cell nonautonomously and promote exploratory foraging behavior in a partially DAF-7-dependent manner. Our data connect natural variation in neuron-specific gene expression to differences in behavior and suggest that genetic variation in neuroendocrine signaling pathways mediating host-microbe interactions may give rise to diversity in animal behavior.
Collapse
Affiliation(s)
- Harksun Lee
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Sonia A. Boor
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Zoë A. Hilbert
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Joshua D. Meisel
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jaeseok Park
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Ye Wang
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Ryan McKeown
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Sylvia E. J. Fischer
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA
- Harvard Medical School Initiative for RNA Medicine, Boston, MA 02115, USA
| | - Erik C. Andersen
- Department of Biology, Johns Hopkins University, Baltimore, MD 21212, USA
| | - Dennis H. Kim
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA
| |
Collapse
|
2
|
Pan Y, Hysinger JD, Yalçın B, Lennon JJ, Byun YG, Raghavan P, Schindler NF, Anastasaki C, Chatterjee J, Ni L, Xu H, Malacon K, Jahan SM, Ivec AE, Aghoghovwia BE, Mount CW, Nagaraja S, Scheaffer S, Attardi LD, Gutmann DH, Monje M. Nf1 mutation disrupts activity-dependent oligodendroglial plasticity and motor learning in mice. Nat Neurosci 2024:10.1038/s41593-024-01654-y. [PMID: 38816530 DOI: 10.1038/s41593-024-01654-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 04/18/2024] [Indexed: 06/01/2024]
Abstract
Neurogenetic disorders, such as neurofibromatosis type 1 (NF1), can cause cognitive and motor impairments, traditionally attributed to intrinsic neuronal defects such as disruption of synaptic function. Activity-regulated oligodendroglial plasticity also contributes to cognitive and motor functions by tuning neural circuit dynamics. However, the relevance of oligodendroglial plasticity to neurological dysfunction in NF1 is unclear. Here we explore the contribution of oligodendrocyte progenitor cells (OPCs) to pathological features of the NF1 syndrome in mice. Both male and female littermates (4-24 weeks of age) were used equally in this study. We demonstrate that mice with global or OPC-specific Nf1 heterozygosity exhibit defects in activity-dependent oligodendrogenesis and harbor focal OPC hyperdensities with disrupted homeostatic OPC territorial boundaries. These OPC hyperdensities develop in a cell-intrinsic Nf1 mutation-specific manner due to differential PI3K/AKT activation. OPC-specific Nf1 loss impairs oligodendroglial differentiation and abrogates the normal oligodendroglial response to neuronal activity, leading to impaired motor learning performance. Collectively, these findings show that Nf1 mutation delays oligodendroglial development and disrupts activity-dependent OPC function essential for normal motor learning in mice.
Collapse
Affiliation(s)
- Yuan Pan
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.
- Department of Symptom Research, University of Texas MD Anderson Cancer Center, Houston, TX, USA.
- Department of Neuro-Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, USA.
| | - Jared D Hysinger
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Belgin Yalçın
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - James J Lennon
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Youkyeong Gloria Byun
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Preethi Raghavan
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Nicole F Schindler
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Corina Anastasaki
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Jit Chatterjee
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Lijun Ni
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Haojun Xu
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Karen Malacon
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Samin M Jahan
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Alexis E Ivec
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Benjamin E Aghoghovwia
- Department of Symptom Research, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Christopher W Mount
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Surya Nagaraja
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Suzanne Scheaffer
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Laura D Attardi
- Department of Radiation Oncology, Stanford University, Stanford, CA, USA
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - David H Gutmann
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA.
| | - Michelle Monje
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA.
| |
Collapse
|
3
|
Birtele M, Del Dosso A, Xu T, Nguyen T, Wilkinson B, Hosseini N, Nguyen S, Urenda JP, Knight G, Rojas C, Flores I, Atamian A, Moore R, Sharma R, Pirrotte P, Ashton RS, Huang EJ, Rumbaugh G, Coba MP, Quadrato G. Non-synaptic function of the autism spectrum disorder-associated gene SYNGAP1 in cortical neurogenesis. Nat Neurosci 2023; 26:2090-2103. [PMID: 37946050 DOI: 10.1038/s41593-023-01477-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 09/29/2023] [Indexed: 11/12/2023]
Abstract
Genes involved in synaptic function are enriched among those with autism spectrum disorder (ASD)-associated rare genetic variants. Dysregulated cortical neurogenesis has been implicated as a convergent mechanism in ASD pathophysiology, yet it remains unknown how 'synaptic' ASD risk genes contribute to these phenotypes, which arise before synaptogenesis. Here, we show that the synaptic Ras GTPase-activating (RASGAP) protein 1 (SYNGAP1, a top ASD risk gene) is expressed within the apical domain of human radial glia cells (hRGCs). In a human cortical organoid model of SYNGAP1 haploinsufficiency, we find dysregulated cytoskeletal dynamics that impair the scaffolding and division plane of hRGCs, resulting in disrupted lamination and accelerated maturation of cortical projection neurons. Additionally, we confirmed an imbalance in the ratio of progenitors to neurons in a mouse model of Syngap1 haploinsufficiency. Thus, SYNGAP1-related brain disorders may arise through non-synaptic mechanisms, highlighting the need to study genes associated with neurodevelopmental disorders (NDDs) in diverse human cell types and developmental stages.
Collapse
Affiliation(s)
- Marcella Birtele
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research at USC, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Ashley Del Dosso
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research at USC, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Tiantian Xu
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research at USC, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Xiangya Hospital, Central South University, Changsha, China
| | - Tuan Nguyen
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research at USC, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Brent Wilkinson
- Department of Psychiatry and Behavioral Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Negar Hosseini
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research at USC, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Sarah Nguyen
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research at USC, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Jean-Paul Urenda
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research at USC, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Gavin Knight
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA
| | - Camilo Rojas
- Departments of Neuroscience and Molecular Medicine, University of Florida Scripps Biomedical Research Institute, Jupiter, FL, USA
- Skaggs Graduate School of Chemical and Biological Sciences, Scripps Research, Jupiter, FL, USA
| | - Ilse Flores
- Department of Psychiatry and Behavioral Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Alexander Atamian
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research at USC, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Roger Moore
- Integrated Mass Spectrometry Shared Resource, City of Hope Comprehensive Cancer Center, Duarte, CA, USA
| | - Ritin Sharma
- Integrated Mass Spectrometry Shared Resource, City of Hope Comprehensive Cancer Center, Duarte, CA, USA
- Cancer and Cell Biology Division, Translational Genomics Research Institute, Phoenix, AZ, USA
| | - Patrick Pirrotte
- Integrated Mass Spectrometry Shared Resource, City of Hope Comprehensive Cancer Center, Duarte, CA, USA
- Cancer and Cell Biology Division, Translational Genomics Research Institute, Phoenix, AZ, USA
| | - Randolph S Ashton
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA
| | - Eric J Huang
- Department of Pathology, University of California, San Francisco, CA, USA
- Eli and Edythe Broad Institute for Stem Cell Research and Regeneration Medicine, University of California, San Francisco, CA, USA
| | - Gavin Rumbaugh
- Departments of Neuroscience and Molecular Medicine, University of Florida Scripps Biomedical Research Institute, Jupiter, FL, USA
- Skaggs Graduate School of Chemical and Biological Sciences, Scripps Research, Jupiter, FL, USA
| | - Marcelo P Coba
- Department of Psychiatry and Behavioral Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Giorgia Quadrato
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
- Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research at USC, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
| |
Collapse
|
4
|
Lee H, Boor SA, Hilbert ZA, Meisel JD, Park J, Wang Y, McKeown R, Fischer SEJ, Andersen EC, Kim DH. Genetic Variants That Modify the Neuroendocrine Regulation of Foraging Behavior in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.09.556976. [PMID: 37745484 PMCID: PMC10515746 DOI: 10.1101/2023.09.09.556976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
The molecular mechanisms underlying diversity in animal behavior are not well understood. A major experimental challenge is determining the contribution of genetic variants that affect neuronal gene expression to differences in behavioral traits. The neuroendocrine TGF-beta ligand, DAF-7, regulates diverse behavioral responses of Caenorhabditis elegans to bacterial food and pathogens. The dynamic neuron-specific expression of daf-7 is modulated by environmental and endogenous bacteria-derived cues. Here, we investigated natural variation in the expression of daf-7 from the ASJ pair of chemosensory neurons and identified common variants in gap-2, encoding a GTPase-Activating Protein homologous to mammalian SynGAP proteins, which modify daf-7 expression cell-non-autonomously and promote exploratory foraging behavior in a DAF-7-dependent manner. Our data connect natural variation in neuron-specific gene expression to differences in behavior and suggest that genetic variation in neuroendocrine signaling pathways mediating host-microbe interactions may give rise to diversity in animal behavior.
Collapse
Affiliation(s)
- Harksun Lee
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School; Boston, 02115, USA
| | - Sonia A. Boor
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School; Boston, 02115, USA
- Department of Biology, Massachusetts Institute of Technology; Cambridge, 02139, USA
| | - Zoë A. Hilbert
- Department of Biology, Massachusetts Institute of Technology; Cambridge, 02139, USA
| | - Joshua D. Meisel
- Department of Biology, Massachusetts Institute of Technology; Cambridge, 02139, USA
| | - Jaeseok Park
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School; Boston, 02115, USA
| | - Ye Wang
- Department of Molecular Biosciences, Northwestern University; Evanston, 60208, USA
| | - Ryan McKeown
- Department of Molecular Biosciences, Northwestern University; Evanston, 60208, USA
| | - Sylvia E. J. Fischer
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School; Boston, 02115, USA
| | - Erik C. Andersen
- Department of Molecular Biosciences, Northwestern University; Evanston, 60208, USA
| | - Dennis H. Kim
- Division of Infectious Diseases, Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School; Boston, 02115, USA
| |
Collapse
|
5
|
Auf der Maur P, Trefny MP, Baumann Z, Vulin M, Correia AL, Diepenbruck M, Kramer N, Volkmann K, Preca BT, Ramos P, Leroy C, Eichlisberger T, Buczak K, Zilli F, Okamoto R, Rad R, Jensen MR, Fritsch C, Zippelius A, Stadler MB, Bentires-Alj M. N-acetylcysteine overcomes NF1 loss-driven resistance to PI3Kα inhibition in breast cancer. Cell Rep Med 2023; 4:101002. [PMID: 37044095 PMCID: PMC10140479 DOI: 10.1016/j.xcrm.2023.101002] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 01/14/2023] [Accepted: 03/16/2023] [Indexed: 04/14/2023]
Abstract
A genome-wide PiggyBac transposon-mediated screen and a resistance screen in a PIK3CAH1047R-mutated murine tumor model reveal NF1 loss in mammary tumors resistant to the phosphatidylinositol 3-kinase α (PI3Kα)-selective inhibitor alpelisib. Depletion of NF1 in PIK3CAH1047R breast cancer cell lines and a patient-derived organoid model shows that NF1 loss reduces sensitivity to PI3Kα inhibition and correlates with enhanced glycolysis and lower levels of reactive oxygen species (ROS). Unexpectedly, the antioxidant N-acetylcysteine (NAC) sensitizes NF1 knockout cells to PI3Kα inhibition and reverts their glycolytic phenotype. Global phospho-proteomics indicates that combination with NAC enhances the inhibitory effect of alpelisib on mTOR signaling. In public datasets of human breast cancer, we find that NF1 is frequently mutated and that such mutations are enriched in metastases, an indication for which use of PI3Kα inhibitors has been approved. Our results raise the attractive possibility of combining PI3Kα inhibition with NAC supplementation, especially in patients with drug-resistant metastases associated with NF1 loss.
Collapse
Affiliation(s)
- Priska Auf der Maur
- Tumor Heterogeneity Metastasis and Resistance, Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland.
| | - Marcel P Trefny
- Cancer Immunology, Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Zora Baumann
- Tumor Heterogeneity Metastasis and Resistance, Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Milica Vulin
- Tumor Heterogeneity Metastasis and Resistance, Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Ana Luisa Correia
- Tumor Heterogeneity Metastasis and Resistance, Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Maren Diepenbruck
- Tumor Heterogeneity Metastasis and Resistance, Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Nicolas Kramer
- Tumor Heterogeneity Metastasis and Resistance, Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Katrin Volkmann
- Tumor Heterogeneity Metastasis and Resistance, Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Bogdan-Tiberius Preca
- Tumor Heterogeneity Metastasis and Resistance, Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Pedro Ramos
- Oncology Research, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Cedric Leroy
- Oncology Research, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | | | - Katarzyna Buczak
- Proteomics Core Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - Federica Zilli
- Tumor Heterogeneity Metastasis and Resistance, Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Ryoko Okamoto
- Tumor Heterogeneity Metastasis and Resistance, Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Roland Rad
- Institute of Molecular Oncology and Functional Genomics, TUM School of Medicine, Technische Universität München, München, Germany; Center for Translational Cancer Research (TranslaTUM), TUM School of Medicine, Technische Universität München, München, Germany; Department of Medicine II, Klinikum rechts der Isar, Technische Universität München, München, Germany; German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | | | - Christine Fritsch
- Oncology Research, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Alfred Zippelius
- Cancer Immunology, Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Michael B Stadler
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland; Swiss Institute of Bioinformatics, Basel, Switzerland; Faculty of Science, University of Basel, Basel, Switzerland
| | - Mohamed Bentires-Alj
- Tumor Heterogeneity Metastasis and Resistance, Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.
| |
Collapse
|
6
|
GAP positions catalytic H-Ras residue Q61 for GTP hydrolysis in molecular dynamics simulations, complicating chemical rescue of Ras deactivation. Comput Biol Chem 2023; 104:107835. [PMID: 36893567 DOI: 10.1016/j.compbiolchem.2023.107835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 02/01/2023] [Accepted: 02/16/2023] [Indexed: 03/05/2023]
Abstract
Functional interaction of Ras signaling proteins with upstream, negative regulatory GTPase activating proteins (GAPs) represents a crucial step in cellular decision making related to growth and survival. Key components of the catalytic transition state for Ras deactivation by GAP-accelerated hydrolysis of Ras-bound guanosine triphosphate (GTP) are thought to include an arginine residue from the GAP (the arginine finger), a glutamine residue from Ras (Q61), and a water molecule that is likely coordinated by Q61 to engage in nucleophilic attack on GTP. Here, we use in-vitro fluorescence experiments to show that 0.1-100 mM concentrations of free arginine, imidazole, and other small nitrogenous molecule fail to accelerate GTP hydrolysis, even in the presence of the catalytic domain of a mutant GAP lacking its arginine finger (R1276A NF1). This result is surprising given that imidazole can chemically rescue enzyme activity in arginine-to-alanine mutant protein tyrosine kinases (PTKs) that share many active site components with Ras/GAP complexes. Complementary all-atom molecular dynamics (MD) simulations reveal that an arginine finger GAP mutant still functions to enhance Ras Q61-GTP interaction, though less extensively than wild-type GAP. This increased Q61-GTP proximity may promote more frequent fluctuations into configurations that enable GTP hydrolysis as a component of the mechanism by which GAPs accelerate Ras deactivation in the face of arginine finger mutations. The failure of small molecule analogs of arginine to chemically rescue catalytic deactivation of Ras is consistent with the idea that the influence of the GAP goes beyond the simple provision of its arginine finger. However, the failure of chemical rescue in the presence of R1276A NF1 suggests that the GAPs arginine finger is either unsusceptible to rescue due to exquisite positioning or that it is involved in complex multivalent interactions. Therefore, in the context of oncogenic Ras proteins with mutations at codons 12 or 13 that inhibit arginine finger penetration toward GTP, drug-based chemical rescue of GTP hydrolysis may have bifunctional chemical/geometric requirements that are more difficult to satisfy than those that result from arginine-to-alanine mutations in other enzymes for which chemical rescue has been demonstrated.
Collapse
|
7
|
A Review of Breast Cancer Risk Factors in Adolescents and Young Adults. Cancers (Basel) 2021; 13:cancers13215552. [PMID: 34771713 PMCID: PMC8583289 DOI: 10.3390/cancers13215552] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 10/29/2021] [Accepted: 11/03/2021] [Indexed: 12/26/2022] Open
Abstract
Simple Summary Cancer diagnosed in patients between the ages of 15 and 39 deserves special consideration. Diagnoses within this cohort of adolescents and young adults include childhood cancers which present at an older age than expected, or an early presentation of cancers that are typically observed in older adults, such as breast cancer. Cancers within this age group are associated with worse disease-free and overall survival rates, and the incidence of these cases are rising. Knowing an individual’s susceptibility to disease can change their clinical management and allow for the risk-testing of relatives. This review discusses the risk factors that contribute to breast cancer in this unique cohort of patients, including inherited genetic risk factors, as well as environmental and lifestyle factors. We also describe risk models that allow clinicians to quantify a patient’s lifetime risk of developing disease. Abstract Cancer in adolescents and young adults (AYAs) deserves special consideration for several reasons. AYA cancers encompass paediatric malignancies that present at an older age than expected, or early-onset of cancers that are typically observed in adults. However, disease diagnosed in the AYA population is distinct to those same cancers which are diagnosed in a paediatric or older adult setting. Worse disease-free and overall survival outcomes are observed in the AYA setting, and the incidence of AYA cancers is increasing. Knowledge of an individual’s underlying cancer predisposition can influence their clinical care and may facilitate early tumour surveillance strategies and cascade testing of at-risk relatives. This information can further influence reproductive decision making. In this review we discuss the risk factors contributing to AYA breast cancer, such as heritable predisposition, environmental, and lifestyle factors. We also describe a number of risk models which incorporate genetic factors that aid clinicians in quantifying an individual’s lifetime risk of disease.
Collapse
|
8
|
Botero V, Stanhope BA, Brown EB, Grenci EC, Boto T, Park SJ, King LB, Murphy KR, Colodner KJ, Walker JA, Keene AC, Ja WW, Tomchik SM. Neurofibromin regulates metabolic rate via neuronal mechanisms in Drosophila. Nat Commun 2021; 12:4285. [PMID: 34257279 PMCID: PMC8277851 DOI: 10.1038/s41467-021-24505-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 06/16/2021] [Indexed: 01/21/2023] Open
Abstract
Neurofibromatosis type 1 is a chronic multisystemic genetic disorder that results from loss of function in the neurofibromin protein. Neurofibromin may regulate metabolism, though the underlying mechanisms remain largely unknown. Here we show that neurofibromin regulates metabolic homeostasis in Drosophila via a discrete neuronal circuit. Loss of neurofibromin increases metabolic rate via a Ras GAP-related domain-dependent mechanism, increases feeding homeostatically, and alters lipid stores and turnover kinetics. The increase in metabolic rate is independent of locomotor activity, and maps to a sparse subset of neurons. Stimulating these neurons increases metabolic rate, linking their dynamic activity state to metabolism over short time scales. Our results indicate that neurofibromin regulates metabolic rate via neuronal mechanisms, suggest that cellular and systemic metabolic alterations may represent a pathophysiological mechanism in neurofibromatosis type 1, and provide a platform for investigating the cellular role of neurofibromin in metabolic homeostasis. Neurofibromatosis type 1 (NF1) is a genetic disorder caused by mutations in neurofibromin and associated with disruptions in physiology and behavior. Here the authors show that neurofibromin regulates metabolic homeostasis via a discrete brain circuit in a Drosophila model of NF1.
Collapse
Affiliation(s)
- Valentina Botero
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL, USA
| | - Bethany A Stanhope
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, USA
| | - Elizabeth B Brown
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, USA
| | - Eliza C Grenci
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL, USA
| | - Tamara Boto
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL, USA.,Department of Physiology, Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
| | - Scarlet J Park
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL, USA
| | - Lanikea B King
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL, USA
| | - Keith R Murphy
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL, USA
| | - Kenneth J Colodner
- Program in Neuroscience and Behavior, Mount Holyoke College, South Hadley, MA, USA
| | - James A Walker
- Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.,Cancer Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Alex C Keene
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, USA
| | - William W Ja
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL, USA
| | - Seth M Tomchik
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL, USA.
| |
Collapse
|
9
|
N Abdel-Aziz N, Y El-Kamah G, A Khairat R, R Mohamed H, Z Gad Y, El-Ghor AM, Amr KS. Mutational spectrum of NF1 gene in 24 unrelated Egyptian families with neurofibromatosis type 1. Mol Genet Genomic Med 2021; 9:e1631. [PMID: 34080803 PMCID: PMC8683698 DOI: 10.1002/mgg3.1631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 09/19/2020] [Accepted: 02/09/2021] [Indexed: 11/25/2022] Open
Abstract
Background Neurofibromatosis 1 (NF1; OMIM# 162200) is a common autosomal dominant genetic disease [incidence: ~1:3500]. In 95% of cases, clinical diagnosis of the disease is based on the presence of at least two of the seven National Institute of Health diagnostic criteria. The molecular pathology underlying this disorder entails mutation in the NF1 gene. The aim of this study was to investigate clinical and molecular characteristics of a cohort of Egyptian NF1 patients. Method This study included 35 clinically diagnosed NF1 patients descending from 25 unrelated families. Patients had ≥2 NIH diagnostic criteria. Examination of NF1 gene was done through direct cDNA sequencing of multiple overlapping fragments. This was supplemented by NF1 multiple ligation dependent probe amplification (MLPA) analysis of leucocytic DNA. Results The clinical presentations encompassed, café‐au‐lait spots in 100% of probands, freckling (52%), neurofibromas (20%), Lisch nodules of the iris (12%), optic pathway glioma (8%), typical skeletal disorders (20%), and positive family history (32%). Mutations could be detected in 24 families (96%). Eight mutations (33%) were novel. Conclusion This study illustrates the underlying molecular pathology among Egyptian NF1 patients for the first time. It also reports on 8 novel mutation expanding pathogenic mutational spectra in the NF1 gene.
Collapse
Affiliation(s)
- Nahla N Abdel-Aziz
- Medical Molecular Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Ghada Y El-Kamah
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Rabab A Khairat
- Medical Molecular Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Hanan R Mohamed
- Zoology Department, Faculty of Science, Cairo University, Cairo, Egypt
| | - Yehia Z Gad
- Medical Molecular Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Akmal M El-Ghor
- Zoology Department, Faculty of Science, Cairo University, Cairo, Egypt
| | - Khalda S Amr
- Medical Molecular Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| |
Collapse
|
10
|
Harder A. MEK inhibitors - novel targeted therapies of neurofibromatosis associated benign and malignant lesions. Biomark Res 2021; 9:26. [PMID: 33863389 PMCID: PMC8052700 DOI: 10.1186/s40364-021-00281-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 03/30/2021] [Indexed: 12/18/2022] Open
Abstract
MAP/ERK kinase 1 and 2 (MEK 1/2) inhibitors (MEKi) are investigated in several trials to treat lesions that arise from pathogenic variants of the Neurofibromatosis type 1 and type 2 genes (NF1, NF2). These trials showed that MEKi are capable to shrink volume of low grade gliomas and plexiform neurofibromas in NF1. Targeting other lesions being associated with a high morbidity in NF1 seems to be promising. Due to involvement of multiple pathways in NF2 associated lesions as well as in malignant tumors, MEKi are also used in combination therapies. This review outlines the current state of MEKi application in neurofibromatosis and associated benign and malignant lesions.
Collapse
Affiliation(s)
- Anja Harder
- Institute of Pathology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 14, 06120, Halle (Saale), Germany. .,Institute of Neuropathology, University Hospital Münster, Münster, Germany. .,Faculty of Health Sciences, Joint Faculty of the Brandenburg University of Technology Cottbus - Senftenberg, the Brandenburg Medical School Theodor Fontane and the University of Potsdam, Potsdam, Germany.
| |
Collapse
|
11
|
Deraredj Nadim W, Hassanaly S, Bénédetti H, Kieda C, Grillon C, Morisset-Lopez S. The GTPase-activating protein-related domain of neurofibromin interacts with MC1R and regulates pigmentation-mediated signaling in human melanocytes. Biochem Biophys Res Commun 2020; 534:758-764. [PMID: 33187641 DOI: 10.1016/j.bbrc.2020.11.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 11/01/2020] [Indexed: 12/24/2022]
Abstract
The melanocortin 1 receptor (MC1R) is a G-protein coupled receptor (GPCR) which plays a major role in controlling melanogenesis. A large body of evidence indicates that GPCRs are part of large protein complexes that are critical for their signal transduction properties. Among proteins which may affect MC1R signaling, neurofibromin (Nf1), a GTPase activating protein (GAP) for Ras, is of special interest as it regulates adenylyl cyclase activity and ERK signaling, two pathways involved in MC1R signaling. Moreover, mutations in this gene encoding Nf1 are responsible for neurofibromatosis type I, a disease inducing hyperpigmented flat skin lesions. Using co-immunoprecipitation and Bioluminescence Resonance Energy Transfer experiments we demonstrated a physical interaction of Nf1 with MC1R. In particular, the GAP domain of Nf1 directly and constitutively interacts with MC1R in melanocytes. Pharmacologic and genetic approaches revealed that the GAP activity of Nf1 is important to regulate intracellular signaling pathways involved in melanogenesis and, consequently, melanogenic enzyme expression and melanin production. These finding shed new light on the understanding and cure of skin pigmentation disorders.
Collapse
Affiliation(s)
- Wissem Deraredj Nadim
- Centre de Biophysique Moléculaire, CNRS UPR4301 Affiliated to the University of Orléans, Rue Charles Sadron, 45071, Orléans, Cedex 2, France
| | - Shalina Hassanaly
- Centre de Biophysique Moléculaire, CNRS UPR4301 Affiliated to the University of Orléans, Rue Charles Sadron, 45071, Orléans, Cedex 2, France
| | - Hélène Bénédetti
- Centre de Biophysique Moléculaire, CNRS UPR4301 Affiliated to the University of Orléans, Rue Charles Sadron, 45071, Orléans, Cedex 2, France
| | - Claudine Kieda
- Centre de Biophysique Moléculaire, CNRS UPR4301 Affiliated to the University of Orléans, Rue Charles Sadron, 45071, Orléans, Cedex 2, France
| | - Catherine Grillon
- Centre de Biophysique Moléculaire, CNRS UPR4301 Affiliated to the University of Orléans, Rue Charles Sadron, 45071, Orléans, Cedex 2, France
| | - Severine Morisset-Lopez
- Centre de Biophysique Moléculaire, CNRS UPR4301 Affiliated to the University of Orléans, Rue Charles Sadron, 45071, Orléans, Cedex 2, France.
| |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
Angara K, Pai ELL, Bilinovich SM, Stafford AM, Nguyen JT, Li KX, Paul A, Rubenstein JL, Vogt D. Nf1 deletion results in depletion of the Lhx6 transcription factor and a specific loss of parvalbumin + cortical interneurons. Proc Natl Acad Sci U S A 2020; 117:6189-6195. [PMID: 32123116 PMCID: PMC7084085 DOI: 10.1073/pnas.1915458117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Neurofibromatosis 1 (NF1) is caused by mutations in the NF1 gene, which encodes the protein, neurofibromin, an inhibitor of Ras activity. Cortical GABAergic interneurons (CINs) are implicated in NF1 pathology, but the cellular and molecular changes to CINs are unknown. We deleted mouse Nf1 from the medial ganglionic eminence, which gives rise to both oligodendrocytes and CINs that express somatostatin and parvalbumin. Nf1 loss led to a persistence of immature oligodendrocytes that prevented later-generated oligodendrocytes from occupying the cortex. Moreover, molecular and cellular properties of parvalbumin (PV)-positive CINs were altered by the loss of Nf1, without changes in somatostatin (SST)-positive CINs. We discovered that loss of Nf1 results in a dose-dependent decrease in Lhx6 expression, the transcription factor necessary to establish SST+ and PV+ CINs, which was rescued by the MEK inhibitor SL327, revealing a mechanism whereby a neurofibromin/Ras/MEK pathway regulates a critical CIN developmental milestone.
Collapse
Affiliation(s)
- Kartik Angara
- Department of Pediatrics and Human Development, Michigan State University, Grand Rapids, MI 49503
| | - Emily Ling-Lin Pai
- Department of Psychiatry, University of California, San Francisco, CA 94158
- Neuroscience Program, University of California, San Francisco, CA 94158
- Nina Ireland Laboratory of Developmental Neurobiology, University of California, San Francisco, CA 94158
| | - Stephanie M Bilinovich
- Department of Pediatrics and Human Development, Michigan State University, Grand Rapids, MI 49503
| | - April M Stafford
- Department of Pediatrics and Human Development, Michigan State University, Grand Rapids, MI 49503
| | - Julie T Nguyen
- Department of Pediatrics and Human Development, Michigan State University, Grand Rapids, MI 49503
| | - Katie X Li
- Department of Pediatrics and Human Development, Michigan State University, Grand Rapids, MI 49503
| | - Anirban Paul
- Department of Neural and Behavioral Sciences, PennState University, Hershey, PA 17033
| | - John L Rubenstein
- Department of Psychiatry, University of California, San Francisco, CA 94158
- Neuroscience Program, University of California, San Francisco, CA 94158
- Nina Ireland Laboratory of Developmental Neurobiology, University of California, San Francisco, CA 94158
| | - Daniel Vogt
- Department of Pediatrics and Human Development, Michigan State University, Grand Rapids, MI 49503;
- Neuroscience Program, Michigan State University, Grand Rapids, MI 49503
| |
Collapse
|
14
|
Joshi V, Upadhyay A, Prajapati VK, Mishra A. How autophagy can restore proteostasis defects in multiple diseases? Med Res Rev 2020; 40:1385-1439. [PMID: 32043639 DOI: 10.1002/med.21662] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 01/03/2020] [Accepted: 01/28/2020] [Indexed: 12/12/2022]
Abstract
Cellular evolution develops several conserved mechanisms by which cells can tolerate various difficult conditions and overall maintain homeostasis. Autophagy is a well-developed and evolutionarily conserved mechanism of catabolism, which endorses the degradation of foreign and endogenous materials via autolysosome. To decrease the burden of the ubiquitin-proteasome system (UPS), autophagy also promotes the selective degradation of proteins in a tightly regulated way to improve the physiological balance of cellular proteostasis that may get perturbed due to the accumulation of misfolded proteins. However, the diverse as well as selective clearance of unwanted materials and regulations of several cellular mechanisms via autophagy is still a critical mystery. Also, the failure of autophagy causes an increase in the accumulation of harmful protein aggregates that may lead to neurodegeneration. Therefore, it is necessary to address this multifactorial threat for in-depth research and develop more effective therapeutic strategies against lethal autophagy alterations. In this paper, we discuss the most relevant and recent reports on autophagy modulations and their impact on neurodegeneration and other complex disorders. We have summarized various pharmacological findings linked with the induction and suppression of autophagy mechanism and their promising preclinical and clinical applications to provide therapeutic solutions against neurodegeneration. The conclusion, key questions, and future prospectives sections summarize fundamental challenges and their possible feasible solutions linked with autophagy mechanism to potentially design an impactful therapeutic niche to treat neurodegenerative diseases and imperfect aging.
Collapse
Affiliation(s)
- Vibhuti Joshi
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Karwar, India
| | - Arun Upadhyay
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Karwar, India
| | - Vijay K Prajapati
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Ajmer, India
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Karwar, India
| |
Collapse
|
15
|
Snezhkina AV, Lukyanova EN, Fedorova MS, Kalinin DV, Melnikova NV, Stepanov OA, Kiseleva MV, Kaprin AD, Pudova EA, Kudryavtseva AV. Novel Genes Associated with the Development of Carotid Paragangliomas. Mol Biol 2019. [DOI: 10.1134/s0026893319040137] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
16
|
Scheffzek K, Shivalingaiah G. Ras-Specific GTPase-Activating Proteins-Structures, Mechanisms, and Interactions. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a031500. [PMID: 30104198 DOI: 10.1101/cshperspect.a031500] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Ras-specific GTPase-activating proteins (RasGAPs) down-regulate the biological activity of Ras proteins by accelerating their intrinsic rate of GTP hydrolysis, basically by a transition state stabilizing mechanism. Oncogenic Ras is commonly not sensitive to RasGAPs caused by interference of mutants with the electronic or steric requirements of the transition state, resulting in up-regulation of activated Ras in respective cells. RasGAPs are modular proteins containing a helical catalytic RasGAP module surrounded by smaller domains that are frequently involved in the subcellular localization or contributing to regulatory features of their host proteins. In this review, we summarize current knowledge about RasGAP structure, mechanism, regulation, and dual-substrate specificity and discuss in some detail neurofibromin, one of the most important negative Ras regulators in cellular growth control and neuronal function.
Collapse
Affiliation(s)
- Klaus Scheffzek
- Division of Biological Chemistry (Biocenter), Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Giridhar Shivalingaiah
- Division of Biological Chemistry (Biocenter), Medical University of Innsbruck, A-6020 Innsbruck, Austria
| |
Collapse
|
17
|
Vasjari L, Bresan S, Biskup C, Pai G, Rubio I. Ras signals principally via Erk in G1 but cooperates with PI3K/Akt for Cyclin D induction and S-phase entry. Cell Cycle 2019; 18:204-225. [PMID: 30560710 DOI: 10.1080/15384101.2018.1560205] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Numerous studies exploring oncogenic Ras or manipulating physiological Ras signalling have established an irrefutable role for Ras as driver of cell cycle progression. Despite this wealth of information the precise signalling timeline and effectors engaged by Ras, particularly during G1, remain obscure as approaches for Ras inhibition are slow-acting and ill-suited for charting discrete Ras signalling episodes along the cell cycle. We have developed an approach based on the inducible recruitment of a Ras-GAP that enforces endogenous Ras inhibition within minutes. Applying this strategy to inhibit Ras stepwise in synchronous cell populations revealed that Ras signaling was required well into G1 for Cyclin D induction, pocket protein phosphorylation and S-phase entry, irrespective of whether cells emerged from quiescence or G2/M. Unexpectedly, Erk, and not PI3K/Akt or Ral was activated by Ras at mid-G1, albeit PI3K/Akt signalling was a necessary companion of Ras/Erk for sustaining cyclin-D levels and G1/S transition. Our findings chart mitogenic signaling by endogenous Ras during G1 and identify limited effector engagement restricted to Raf/MEK/Erk as a cogent distinction from oncogenic Ras signalling.
Collapse
Affiliation(s)
- Ledia Vasjari
- a Institute of Molecular Cell Biology, Center for Molecular Biomedicine , Jena University Hospital , Jena , Germany
| | - Stephanie Bresan
- a Institute of Molecular Cell Biology, Center for Molecular Biomedicine , Jena University Hospital , Jena , Germany
| | - Christoph Biskup
- b Biomolecular Photonics Group , Jena University Hospital , Jena , Germany
| | - Govind Pai
- a Institute of Molecular Cell Biology, Center for Molecular Biomedicine , Jena University Hospital , Jena , Germany
| | - Ignacio Rubio
- a Institute of Molecular Cell Biology, Center for Molecular Biomedicine , Jena University Hospital , Jena , Germany
| |
Collapse
|
18
|
Cui Y, Morrison H. Construction of cloning-friendly minigenes for mammalian expression of full-length human NF1 isoforms. Hum Mutat 2018; 40:187-192. [DOI: 10.1002/humu.23681] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 10/23/2018] [Accepted: 11/06/2018] [Indexed: 01/17/2023]
Affiliation(s)
- Yan Cui
- Leibniz Institute on Aging, Fritz Lipmann Institute (FLI); Jena Germany
| | - Helen Morrison
- Leibniz Institute on Aging, Fritz Lipmann Institute (FLI); Jena Germany
| |
Collapse
|
19
|
Abstract
The MAPK pathway is a prominent intracellular signaling pathway regulating various intracellular functions. Components of this pathway are mutated in a related collection of congenital syndromes collectively referred to as neuro-cardio-facio-cutaneous syndromes (NCFC) or Rasopathies. Recently, it has been appreciated that these disorders are associated with autism spectrum disorders (ASD). In addition, idiopathic ASD has also implicated the MAPK signaling cascade as a common pathway that is affected by many of the genetic variants that have been found to be linked to ASDs. This chapter describes the components of the MAPK pathway and how it is regulated. Furthermore, this chapter will highlight the various functions of the MAPK pathway during both embryonic development of the central nervous system (CNS) and its roles in neuronal physiology and ultimately, behavior. Finally, we will summarize the perturbations to MAPK signaling in various models of autism spectrum disorders and Rasopathies to highlight how dysregulation of this pivotal pathway may contribute to the pathogenesis of autism.
Collapse
|
20
|
Agrahari AK, Muskan M, George Priya Doss C, Siva R, Zayed H. Computational insights of K1444N substitution in GAP-related domain of NF1 gene associated with neurofibromatosis type 1 disease: a molecular modeling and dynamics approach. Metab Brain Dis 2018; 33:1443-1457. [PMID: 29804243 DOI: 10.1007/s11011-018-0251-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Accepted: 05/17/2018] [Indexed: 12/18/2022]
Abstract
The NF1 gene encodes for neurofibromin protein, which is ubiquitously expressed, but most highly in the central nervous system. Non-synonymous SNPs (nsSNPs) in the NF1 gene were found to be associated with Neurofibromatosis Type 1 disease, which is characterized by the growth of tumors along nerves in the skin, brain, and other parts of the body. In this study, we used several in silico predictions tools to analyze 16 nsSNPs in the RAS-GAP domain of neurofibromin, the K1444N (K1423N) mutation was predicted as the most pathogenic. The comparative molecular dynamic simulation (MDS; 50 ns) between the wild type and the K1444N (K1423N) mutant suggested a significant change in the electrostatic potential. In addition, the RMSD, RMSF, Rg, hydrogen bonds, and PCA analysis confirmed the loss of flexibility and increase in compactness of the mutant protein. Further, SASA analysis revealed exchange between hydrophobic and hydrophilic residues from the core of the RAS-GAP domain to the surface of the mutant domain, consistent with the secondary structure analysis that showed significant alteration in the mutant protein conformation. Our data concludes that the K1444N (K1423N) mutant lead to increasing the rigidity and compactness of the protein. This study provides evidence of the benefits of the computational tools in predicting the pathogenicity of genetic mutations and suggests the application of MDS and different in silico prediction tools for variant assessment and classification in genetic clinics.
Collapse
Affiliation(s)
- Ashish Kumar Agrahari
- Department of Integrative Biology, School of Biosciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India
| | - Meghana Muskan
- Department of Integrative Biology, School of Biosciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India
| | - C George Priya Doss
- Department of Integrative Biology, School of Biosciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India.
| | - R Siva
- Department of Integrative Biology, School of Biosciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India
| | - Hatem Zayed
- Department of Biomedical Sciences, College of Health and Sciences, Qatar University, Doha, Qatar.
| |
Collapse
|
21
|
Isakov O, Wallis D, Evans DG, Ben-Shachar S. Exhaustive non-synonymous variants functionality prediction enables high resolution characterization of the neurofibromin architecture. EBioMedicine 2018; 36:508-516. [PMID: 30274822 PMCID: PMC6197713 DOI: 10.1016/j.ebiom.2018.09.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 09/11/2018] [Accepted: 09/21/2018] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Neurofibromatosis type I (NF1) is caused by heterozygous loss-of-function variants in the NF1 gene encoding neurofibromin which serves as a tumor suppressor that inhibits RAS signaling and regulates cell proliferation and differentiation. While, the only well-established functional domain in the NF1 protein is the GAP-related domain (GRD), most of the identified non-truncating disease-causing variants are located outside of this domain, supporting the existence of other important disease-associated domains. Identifying these domains may reveal novel functions of NF1. METHODS By implementing inferential statistics combined with machine-learning methods, we developed a novel NF1-specific functional prediction model that focuses on nonsynonymous single nucleotide variants (SNVs). The model enables annotating all possible NF1 nonsynonymous variants, thus mapping the range of pathogenic non-truncating variants at the codon level across the NF1 gene. FINDINGS The generated model demonstrates high absolute prediction value for missense and splice-site variations (area under the ROC curve of 0.96) outperforming 14 other established models. By reviewing the entire dataset of nonsynonymous variants, two novel domains (Armadillo type fold 1 and 2) were identified as being associated with pathogenicity (OR 1.86; CI 1.04 to 3.34 and OR 2.08; CI 1.08 to 4.04, respectively; P < .05). Specific exons and codons associated with increased pathogenicity were also detected along the gene inside and outside the GRD domain. INTERPRETATION The developed model, enabled better prediction of pathogenicity for variants in NF1 gene, as well as elucidation of novel NF1-associated domains in addition to the GRD. FUND: This work was partially supported by the Kahn foundation. DGE is supported by the all Manchester NIHR Biomedical Research Centre (IS-brC-1215-20007).
Collapse
Affiliation(s)
- Ofer Isakov
- Department of Internal Medicine "T", Sourasky Medical Center, Tel Aviv, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Deeann Wallis
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, United States.
| | - D Gareth Evans
- Manchester Centre for Genomic Medicine, Division of Evolution and Genomic Science, University of Manchester, Manchester University Hospitals NHS Foundation Trust, Manchester, UK.
| | - Shay Ben-Shachar
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Gilbert Israeli Neurofibromatosis Center, Tel-Aviv Medical Center, Tel-Aviv, Israel.
| |
Collapse
|
22
|
The Many Faces of Rap1 GTPase. Int J Mol Sci 2018; 19:ijms19102848. [PMID: 30241315 PMCID: PMC6212855 DOI: 10.3390/ijms19102848] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 09/16/2018] [Accepted: 09/17/2018] [Indexed: 12/12/2022] Open
Abstract
This review addresses the issue of the numerous roles played by Rap1 GTPase (guanosine triphosphatase) in different cell types, in terms of both physiology and pathology. It is one among a myriad of small G proteins with endogenous GTP-hydrolyzing activity that is considerably stimulated by posttranslational modifications (geranylgeranylation) or guanine nucleotide exchange factors (GEFs), and inhibited by GTPase-activating proteins (GAPs). Rap1 is a ubiquitous protein that plays an essential role in the control of metabolic processes, such as signal transduction from plasma membrane receptors, cytoskeleton rearrangements necessary for cell division, intracellular and substratum adhesion, as well as cell motility, which is needed for extravasation or fusion. We present several examples of how Rap1 affects cells and organs, pointing to possible molecular manipulations that could have application in the therapy of several diseases.
Collapse
|
23
|
Abstract
RASopathies are a heterogeneous group of genetic syndromes characterized by mutations in genes that regulate cellular processes, including proliferation, differentiation, survival, migration, and metabolism. Excluding congenital heart defects, hypertrophic cardiomyopathy is the most frequent cardiovascular defect in patients affected by RASopathies. A worse outcome (in terms of surgical risk and/or mortality) has been described in a specific subset of Rasopathy patients with early onset, severe hypertrophic cardiomyopathy presenting with heart failure. New short-term therapy with a mammalian target of rapamycin inhibitor has recently been used to prevent heart failure in these patients with a severe form of hypertrophic cardiomyopathy.
Collapse
|
24
|
Gonzalez PP, Kim J, Galvao RP, Cruickshanks N, Abounader R, Zong H. p53 and NF 1 loss plays distinct but complementary roles in glioma initiation and progression. Glia 2018; 66:999-1015. [PMID: 29392777 PMCID: PMC7808243 DOI: 10.1002/glia.23297] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 12/03/2017] [Accepted: 01/09/2018] [Indexed: 12/19/2022]
Abstract
Malignant glioma is one of the deadliest types of cancer. Understanding how the cell of origin progressively evolves toward malignancy in greater detail could provide mechanistic insights and lead to novel concepts for tumor prevention and therapy. Previously we have identified oligodendrocyte precursor cell (OPC) as the cell of origin for glioma following the concurrent deletion of p53 and NF1 using a mouse genetic mosaic system that can reveal mutant cells prior to malignancy. In the current study, we set out to deconstruct the gliomagenic process in two aspects. First, we determined how the individual loss of p53 or NF1 contributes to aberrant behaviors of OPCs. Second, we determined how signaling aberrations in OPCs progressively change from pre-malignant to transformed stages. We found that while the deletion of NF1 leads to mutant OPC expansion through increased proliferation and decreased differentiation, the deletion of p53 impairs OPC senescence. Signaling analysis showed that, while PI3K and MEK pathways go through stepwise over-activation, mTOR signaling remains at the basal level in pre-transforming mutant OPCs but is abruptly up-regulated in tumor OPCs. Finally, inhibiting mTOR via pharmacological or genetic methods, led to a significant blockade of gliomagenesis but had little impact on pre-transforming mutant OPCs, suggesting that mTOR is necessary for final transformation but not early progression. In summary, our findings show that deconstructing the tumorigenic process reveals specific aberrations caused by individual gene mutations and altered signaling events at precise timing during tumor progression, which may shed light on tumor-prevention strategies.
Collapse
Affiliation(s)
- Phillippe P Gonzalez
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, 1340 Jefferson Park Ave, Charlottesville, Virginia
| | - Jungeun Kim
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, 1340 Jefferson Park Ave, Charlottesville, Virginia
| | - Rui Pedro Galvao
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, 1340 Jefferson Park Ave, Charlottesville, Virginia
| | - Nichola Cruickshanks
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, 1340 Jefferson Park Ave, Charlottesville, Virginia
| | - Roger Abounader
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, 1340 Jefferson Park Ave, Charlottesville, Virginia
| | - Hui Zong
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, 1340 Jefferson Park Ave, Charlottesville, Virginia
| |
Collapse
|
25
|
Rosset C, Vairo F, Cristina Bandeira I, Fonini M, Netto CBO, Ashton-Prolla P. Clinical and molecular characterization of neurofibromatosis in southern Brazil. Expert Rev Mol Diagn 2018; 18:577-586. [PMID: 29685074 DOI: 10.1080/14737159.2018.1468256] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVES Neurofibromatoses (type 1: NF1; type 2: NF2) are autosomal dominant tumor predisposition syndromes mostly caused by loss-of-function mutations in the tumor suppressor genes NF1 and NF2, respectively. Genotyping is important for correct diagnosis of these diseases. The authors aimed to characterize NF1 and NF2 variants in patients from Southern Brazil. METHODS Ninety-three unrelated probands with NF1 and 7 unrelated probands with NF2 features were recruited from an Oncogenetics center in Southern Brazil. Two next generation sequencing panels were customized to identify point mutations: NF1 (NF1, RNF135, and SUZ12 genes) and NF2 (NF2 and SMARCB1 genes). Large rearrangements were assessed by Multiplex Ligation-dependent Probe Amplification. RESULTS Sixty-eight heterozygous NF1 variants were identified in 75/93 probands (80%) and 3 heterozygous NF2 variants were identified in 3/7 probands (43%). In NF1, 59 (87%) variants were pathogenic (4 large rearrangements - 6%), 6 (9%) were likely pathogenic, 3 (4%) were variants of uncertain significance and 28 (41%) were novel. In NF2, all variants were pathogenic. No novel genotype-phenotype correlations were observed; however, previously described correlations were confirmed in our cohort. CONCLUSION The clinical and molecular characterization of neurofibromatoses in different populations is very important to provide further insights into the pathogenesis of these diseases.
Collapse
Affiliation(s)
- Clévia Rosset
- a Laboratório de Medicina Genômica - Centro de Pesquisa Experimental , Hospital de Clínicas de Porto Alegre , Porto Alegre , Brazil.,b Programa de Pós-graduação em Genética e Biologia Molecular , Universidade Federal do Rio Grande do Sul , Porto Alegre , Brazil
| | - Filippo Vairo
- c Serviço de Genética Médica , Hospital de Clínicas de Porto Alegre , Porto Alegre , Brazil
| | - Isabel Cristina Bandeira
- a Laboratório de Medicina Genômica - Centro de Pesquisa Experimental , Hospital de Clínicas de Porto Alegre , Porto Alegre , Brazil.,b Programa de Pós-graduação em Genética e Biologia Molecular , Universidade Federal do Rio Grande do Sul , Porto Alegre , Brazil
| | - Maievi Fonini
- a Laboratório de Medicina Genômica - Centro de Pesquisa Experimental , Hospital de Clínicas de Porto Alegre , Porto Alegre , Brazil
| | | | - Patricia Ashton-Prolla
- a Laboratório de Medicina Genômica - Centro de Pesquisa Experimental , Hospital de Clínicas de Porto Alegre , Porto Alegre , Brazil.,b Programa de Pós-graduação em Genética e Biologia Molecular , Universidade Federal do Rio Grande do Sul , Porto Alegre , Brazil.,c Serviço de Genética Médica , Hospital de Clínicas de Porto Alegre , Porto Alegre , Brazil.,d Departamento de Genética , Universidade Federal do Rio Grande do Sul , Porto Alegre , Brazil
| |
Collapse
|
26
|
Wallis D, Li K, Lui H, Hu K, Chen MJ, Li J, Kang J, Das S, Korf BR, Kesterson RA. Neurofibromin (NF1) genetic variant structure-function analyses using a full-length mouse cDNA. Hum Mutat 2018. [PMID: 29522274 DOI: 10.1002/humu.23421] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Neurofibromatosis type 1 (NF1) is caused by pathogenic variants or mutations in the NF1 gene that encodes neurofibromin. We describe here a new approach to determining the functional consequences of NF1 genetic variants. We established a heterologous cell culture expression system using a full-length mouse Nf1 cDNA (mNf1) and human cell lines. We demonstrate that the full-length murine cDNA produces a > 250 kDa neurofibromin protein that is capable of modulating Ras signaling. We created mutant cDNAs representing NF1 patient variants with different clinically relevant phenotypes, and assessed their ability to produce mature neurofibromin and restore Nf1 activity in NF1-/- cells. These cDNAs represent variants in multiple protein domains and various types of clinically relevant predicted variants. This approach will help advance research on neurofibromin structure and function, determine pathogenicity for missense variants, and allow for the development of activity assays and variant-directed therapeutics.
Collapse
Affiliation(s)
- Deeann Wallis
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL
| | - Kairong Li
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL
| | - Hui Lui
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL
| | - Ke Hu
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL
| | - Mei-Jan Chen
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL
| | - Jing Li
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL
| | - Jungsoon Kang
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL
| | - Shamik Das
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL
| | - Bruce R Korf
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL
| | - Robert A Kesterson
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL
| |
Collapse
|
27
|
Summers MA, Vasiljevski ER, Mikulec K, Peacock L, Little DG, Schindeler A. Developmental dosing with a MEK inhibitor (PD0325901) rescues myopathic features of the muscle-specific but not limb-specific Nf1 knockout mouse. Mol Genet Metab 2018; 123:518-525. [PMID: 29477258 DOI: 10.1016/j.ymgme.2018.02.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 02/15/2018] [Accepted: 02/15/2018] [Indexed: 12/11/2022]
Abstract
Neurofibromatosis Type 1 (NF1) is a common autosomal dominant genetic disorder While NF1 is primarily associated with predisposition for tumor formation, muscle weakness has emerged as having a significant impact on quality of life. NF1 inactivation is linked with a canonical upregulation Ras-MEK-ERK signaling. This in this study we tested the capacity of the small molecule MEK inhibitor PD0325901 to influence the intramyocellular lipid accumulation associated with NF1 deficiency. Established murine models of tissue specific Nf1 deletion in skeletal muscle (Nf1MyoD-/-) and limb mesenchyme (Nf1Prx1-/-) were tested. Developmental PD0325901 dosing of dams pregnant with Nf1MyoD-/- progeny rescued the phenotype of day 3 pups including body weight and lipid accumulation by Oil Red O staining. In contrast, PD0325901 treatment of 4 week old Nf1Prx1-/- mice for 8 weeks had no impact on body weight, muscle wet weight, activity, or intramyocellular lipid. Examination of day 3 Nf1Prx1-/- pups showed differences between the two tissue-specific knockout strains, with lipid staining greatest in Nf1MyoD-/- mice, and fibrosis higher in Nf1Prx1-/- mice. These data show that a MEK/ERK dependent mechanism underlies NF1 muscle metabolism during development. However, crosstalk from Nf1-deficient non-muscle mesenchymal cells may impact upon muscle metabolism and fibrosis in neonatal and mature myofibers.
Collapse
Affiliation(s)
- Matthew A Summers
- Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Westmead, NSW, Australia; Discipline of Paediatrics & Child Heath, Faculty of Medicine, University of Sydney, Camperdown, NSW, Australia
| | - Emily R Vasiljevski
- Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Westmead, NSW, Australia; Discipline of Paediatrics & Child Heath, Faculty of Medicine, University of Sydney, Camperdown, NSW, Australia
| | - Kathy Mikulec
- Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - Lauren Peacock
- Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - David G Little
- Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Westmead, NSW, Australia; Discipline of Paediatrics & Child Heath, Faculty of Medicine, University of Sydney, Camperdown, NSW, Australia
| | - Aaron Schindeler
- Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Westmead, NSW, Australia; Discipline of Paediatrics & Child Heath, Faculty of Medicine, University of Sydney, Camperdown, NSW, Australia.
| |
Collapse
|
28
|
Genetic inhibition of Anaplastic Lymphoma Kinase rescues cognitive impairments in Neurofibromatosis 1 mutant mice. Behav Brain Res 2017; 321:148-156. [DOI: 10.1016/j.bbr.2017.01.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 11/23/2016] [Accepted: 01/01/2017] [Indexed: 02/07/2023]
|
29
|
The NF1 gene in tumor syndromes and melanoma. J Transl Med 2017; 97:146-157. [PMID: 28067895 PMCID: PMC5413358 DOI: 10.1038/labinvest.2016.142] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 11/10/2016] [Accepted: 11/29/2016] [Indexed: 02/06/2023] Open
Abstract
Activation of the RAS/MAPK pathway is critical in melanoma. Melanoma can be grouped into four molecular subtypes based on their main genetic driver: BRAF-mutant, NRAS-mutant, NF1-mutant, and triple wild-type tumors. The NF1 protein, neurofibromin 1, negatively regulates RAS proteins through GTPase activity. Germline mutations in NF1 cause neurofibromatosis type I, a common genetic tumor syndrome caused by dysregulation of the RAS/MAPK pathway, ie, RASopathy. Melanomas with NF1 mutations typically occur on chronically sun-exposed skin or in older individuals, show a high mutation burden, and are wild-type for BRAF and NRAS. Additionally, NF1 mutations characterize certain clinicopathologic melanoma subtypes, specifically desmoplastic melanoma. This review discusses the current knowledge of the NF1 gene and neurofibromin 1 in neurofibromatosis type I and in melanoma.
Collapse
|
30
|
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.
Collapse
|
31
|
Handley MT, Carpanini SM, Mali GR, Sidjanin DJ, Aligianis IA, Jackson IJ, FitzPatrick DR. Warburg Micro syndrome is caused by RAB18 deficiency or dysregulation. Open Biol 2016; 5:150047. [PMID: 26063829 PMCID: PMC4632505 DOI: 10.1098/rsob.150047] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
RAB18, RAB3GAP1, RAB3GAP2 and TBC1D20 are each mutated in Warburg Micro syndrome, a rare autosomal recessive multisystem disorder. RAB3GAP1 and RAB3GAP2 form a binary ‘RAB3GAP’ complex that functions as a guanine-nucleotide exchange factor (GEF) for RAB18, whereas TBC1D20 shows modest RAB18 GTPase-activating (GAP) activity in vitro. Here, we show that in the absence of functional RAB3GAP or TBC1D20, the level, localization and dynamics of cellular RAB18 is altered. In cell lines where TBC1D20 is absent from the endoplasmic reticulum (ER), RAB18 becomes more stably ER-associated and less cytosolic than in control cells. These data suggest that RAB18 is a physiological substrate of TBC1D20 and contribute to a model in which a Rab-GAP can be essential for the activity of a target Rab. Together with previous reports, this indicates that Warburg Micro syndrome can be caused directly by loss of RAB18, or indirectly through loss of RAB18 regulators RAB3GAP or TBC1D20.
Collapse
Affiliation(s)
- Mark T Handley
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Sarah M Carpanini
- Division of Neurobiology, The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK
| | - Girish R Mali
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Duska J Sidjanin
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Irene A Aligianis
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Ian J Jackson
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - David R FitzPatrick
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| |
Collapse
|
32
|
Bakker AC, La Rosa S, Sherman LS, Knight P, Lee H, Pancza P, Nievo M. Neurofibromatosis as a gateway to better treatment for a variety of malignancies. Prog Neurobiol 2016; 152:149-165. [PMID: 26854064 DOI: 10.1016/j.pneurobio.2016.01.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 01/25/2016] [Accepted: 01/25/2016] [Indexed: 12/23/2022]
Abstract
The neurofibromatoses (NF) are a group of rare genetic disorders that can affect all races equally at an incidence from 1:3000 (NF1) to a log unit lower for NF2 and schwannomatosis. Since the research community is reporting an increasing number of malignant cancers that carry mutations in the NF genes, the general interest of both the research and pharma community is increasing and the authors saw an opportunity to present a novel, fresh approach to drug discovery in NF. The aim of the paper is to challenge the current drug discovery approach to NF, whereby existing targeted therapies that are either in the clinic or on the market for other disease indications are repurposed for NF. We offer a suggestion for an alternative drug discovery approach. In the new approach, selective and tolerable targeted therapies would be developed for NF and later expanded to patients with more complex diseases such as malignant cancer in which the NF downstream pathways are deregulated. The Children's Tumor Foundation, together with some other major NF funders, is playing a key role in funding critical initiatives that will accelerate the development of better targeted therapies for NF patients, while these novel, innovative treatments could potentially be beneficial to molecularly characterized cancer patients in which NF mutations have been identified.
Collapse
Affiliation(s)
- Annette C Bakker
- Children's Tumor Foundation, 120, Wall Street, 16th Floor, New York 10005, United States
| | - Salvatore La Rosa
- Children's Tumor Foundation, 120, Wall Street, 16th Floor, New York 10005, United States
| | - Larry S Sherman
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185th Avenue, Beaverton, OR 97006, United States
| | - Pamela Knight
- Children's Tumor Foundation, 120, Wall Street, 16th Floor, New York 10005, United States
| | - Hyerim Lee
- Children's Tumor Foundation, 120, Wall Street, 16th Floor, New York 10005, United States
| | - Patrice Pancza
- Children's Tumor Foundation, 120, Wall Street, 16th Floor, New York 10005, United States
| | - Marco Nievo
- Children's Tumor Foundation, 120, Wall Street, 16th Floor, New York 10005, United States.
| |
Collapse
|
33
|
Hirata Y, Brems H, Suzuki M, Kanamori M, Okada M, Morita R, Llano-Rivas I, Ose T, Messiaen L, Legius E, Yoshimura A. Interaction between a Domain of the Negative Regulator of the Ras-ERK Pathway, SPRED1 Protein, and the GTPase-activating Protein-related Domain of Neurofibromin Is Implicated in Legius Syndrome and Neurofibromatosis Type 1. J Biol Chem 2015; 291:3124-34. [PMID: 26635368 DOI: 10.1074/jbc.m115.703710] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Indexed: 11/06/2022] Open
Abstract
Constitutional heterozygous loss-of-function mutations in the SPRED1 gene cause a phenotype known as Legius syndrome, which consists of symptoms of multiple café-au-lait macules, axillary freckling, learning disabilities, and macrocephaly. Legius syndrome resembles a mild neurofibromatosis type 1 (NF1) phenotype. It has been demonstrated that SPRED1 functions as a negative regulator of the Ras-ERK pathway and interacts with neurofibromin, the NF1 gene product. However, the molecular details of this interaction and the effects of the mutations identified in Legius syndrome and NF1 on this interaction have not yet been investigated. In this study, using a yeast two-hybrid system and an immunoprecipitation assay in HEK293 cells, we found that the SPRED1 EVH1 domain interacts with the N-terminal 16 amino acids and the C-terminal 20 amino acids of the GTPase-activating protein (GAP)-related domain (GRD) of neurofibromin, which form two crossing α-helix coils outside the GAP domain. These regions have been shown to be dispensable for GAP activity and are not present in p120(GAP). Several mutations in these N- and C-terminal regions of the GRD in NF1 patients and pathogenic missense mutations in the EVH1 domain of SPRED1 in Legius syndrome reduced the binding affinity between the EVH1 domain and the GRD. EVH1 domain mutations with reduced binding to the GRD also disrupted the ERK suppression activity of SPRED1. These data clearly demonstrate that SPRED1 inhibits the Ras-ERK pathway by recruiting neurofibromin to Ras through the EVH1-GRD interaction, and this study also provides molecular basis for the pathogenic mutations of NF1 and Legius syndrome.
Collapse
Affiliation(s)
- Yasuko Hirata
- From the Department of Microbiology and Immunology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Hilde Brems
- the Department of Human Genetics, Catholic University of Leuven, 3000 Leuven, Belgium
| | - Mayu Suzuki
- From the Department of Microbiology and Immunology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Mitsuhiro Kanamori
- From the Department of Microbiology and Immunology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Masahiro Okada
- From the Department of Microbiology and Immunology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Rimpei Morita
- From the Department of Microbiology and Immunology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Isabel Llano-Rivas
- the Department of Genetics, Hospital Universitario Cruces, BioCruces Health Research Institute, Biscay, Spain
| | - Toyoyuki Ose
- Department of Pharmaceutical Sciences, Hokkaido University, N12W6, Sapporo 060-0812, Japan, and
| | - Ludwine Messiaen
- the Medical Genomics Laboratory, Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Eric Legius
- the Department of Human Genetics, Catholic University of Leuven, 3000 Leuven, Belgium
| | - Akihiko Yoshimura
- From the Department of Microbiology and Immunology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan,
| |
Collapse
|
34
|
Čizmárová M, Hlinková K, Bertok S, Kotnik P, Duba HC, Bertalan R, Poločková K, Košťálová Ľ, Pribilincová Z, Hlavatá A, Kovács L, Ilenčíková D. New Mutations Associated with Rasopathies in a Central European Population and Genotype-Phenotype Correlations. Ann Hum Genet 2015; 80:50-62. [PMID: 26607044 DOI: 10.1111/ahg.12140] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Accepted: 08/14/2015] [Indexed: 01/30/2023]
Abstract
We performed the genetic analysis of Rasopathy syndromes in patients from Central European by direct sequencing followed by next generation sequencing of genes associated with Rasopathies. All 51 patients harboured the typical features of Rasopathy syndromes. Thirty-five mutations were identified in the examined patients (22 in PTPN11, two in SOS1, one in RIT1, one in SHOC2, two in HRAS, three in BRAF, two in MAP2K1 and two in the NF1 gene). Two of them (p.Gly392Glu in the BRAF gene and p.Gln164Lys in the MAP2K1 gene) were novel with a potentially pathogenic effect on the structure of these proteins. Statistically significant differences in the presence of pulmonary stenosis (63.64% vs. 23.81%, P = 0.013897) and cryptorchidism (76.47% vs. 30%, P = 0.040224) were identified as the result of comparison of the prevalence of phenotypic features in patients with the phenotype of Noonan syndrome and mutation in the PTPN11 gene, with the prevalence of the same features in patients without PTPN11 mutation. Cryptorchidism as a statistically significant feature in our patients with PTPN11 mutation was not reported as significant in other European countries (Germany, Italy and Greece). The majority of mutations were clustered in exons 3 (45.45%), 8 (22.73%), and 13 (22.73%) of the PTPN11 gene.
Collapse
Affiliation(s)
- M Čizmárová
- 2nd Department of Pediatrcs, University Children's Hospital, Bratislava, Slovakia
| | - K Hlinková
- 2nd Department of Pediatrcs, University Children's Hospital, Bratislava, Slovakia
| | - S Bertok
- Department of Endocrinology, Diabetes and Metabolic Diseases, University Children's Hospital, Ljubljana, Slovenia
| | - P Kotnik
- Department of Endocrinology, Diabetes and Metabolic Diseases, University Children's Hospital, Ljubljana, Slovenia
| | - H C Duba
- Department of Human Genetics, Women's and Children's Clinic, Linz, Austria
| | - R Bertalan
- Department od Pediatric Endocrinology, University Teaching Hospital, Veszprem, Hungary
| | - K Poločková
- Department of Pediatric Endocrinology, Hospital with Policlinic, Karviná, Czech Republic
| | - Ľ Košťálová
- 2nd Department of Pediatrcs, University Children's Hospital, Bratislava, Slovakia
| | - Z Pribilincová
- 2nd Department of Pediatrcs, University Children's Hospital, Bratislava, Slovakia
| | - A Hlavatá
- 2nd Department of Pediatrcs, University Children's Hospital, Bratislava, Slovakia
| | - L Kovács
- 2nd Department of Pediatrcs, University Children's Hospital, Bratislava, Slovakia
| | - D Ilenčíková
- 2nd Department of Pediatrcs, University Children's Hospital, Bratislava, Slovakia.,Department of Human Genetics, Women's and Children's Clinic, Linz, Austria
| |
Collapse
|
35
|
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
Collapse
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
| |
Collapse
|
36
|
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.
Collapse
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
| |
Collapse
|
37
|
Rad E, Dodd K, Thomas L, Upadhyaya M, Tee A. STAT3 and HIF1α Signaling Drives Oncogenic Cellular Phenotypes in Malignant Peripheral Nerve Sheath Tumors. Mol Cancer Res 2015; 13:1149-60. [PMID: 25833823 DOI: 10.1158/1541-7786.mcr-14-0182] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 03/26/2015] [Indexed: 11/16/2022]
Abstract
UNLABELLED Therapeutic options are limited for neurofibromatosis type 1 (NF1)-associated malignant peripheral nerve sheath tumors (MPNST) and clinical trials using drug agents have so far been unsuccessful. This lack of clinical success is likely attributed to high levels of intratumoral molecular heterogeneity and variations in signal transduction within MPNSTs. To better explore the variance of malignant signaling properties within heterogeneous MPNSTs, four MPNST cell lines (ST8814, S462, S1844.1, and S1507.2) were used. The data demonstrate that small-molecule inhibition of the MET proto-oncogene and mTOR had variable outcome when preventing wound healing, cell migration, and invasion, with the S462 cells being highly resistant to both. Of interest, targeted inhibition of the STAT3 transcription factor suppressed wound healing, cell migration, invasion, and tumor formation in all four MPNST lines, which demonstrates that unlike MET and mTOR, STAT3 functions as a common driver of tumorigenesis in NF1-MPNSTs. Of clinical importance, STAT3 knockdown was sufficient to block the expression of hypoxia-inducible factor (HIF)1α, HIF2α, and VEGF-A in all four MPNST lines. Finally, the data demonstrate that wound healing, cell migration, invasion, and tumor formation through STAT3 are highly dependent on HIF signaling, where knockdown of HIF1α ablated these oncogenic facets of STAT3. IMPLICATIONS This research reveals that aberrant STAT3 and HIF1a activity drives tumor progression in MPNSTs, indicating that inhibition of the STAT3/HIF1α/VEGF-A signaling axis is a viable treatment strategy.
Collapse
Affiliation(s)
- Ellie Rad
- Institute of Cancer and Genetics, Cardiff University, Heath Park, Cardiff, Wales, United Kingdom
| | - Kayleigh Dodd
- Institute of Cancer and Genetics, Cardiff University, Heath Park, Cardiff, Wales, United Kingdom
| | - Laura Thomas
- Institute of Cancer and Genetics, Cardiff University, Heath Park, Cardiff, Wales, United Kingdom
| | - Meena Upadhyaya
- Institute of Cancer and Genetics, Cardiff University, Heath Park, Cardiff, Wales, United Kingdom
| | - Andrew Tee
- Institute of Cancer and Genetics, Cardiff University, Heath Park, Cardiff, Wales, United Kingdom.
| |
Collapse
|
38
|
Kumari N, Saxena S, Agrawal U. Exosomal protein interactors as emerging therapeutic targets in urothelial bladder cancer. J Egypt Natl Canc Inst 2015; 27:51-8. [PMID: 25726332 DOI: 10.1016/j.jnci.2015.02.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 02/04/2015] [Accepted: 02/04/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Exosomes are rich sources of biological material (proteins and nucleic acids) secreted by both tumor and normal cells, and found in urine of urinary bladder cancer patients. OBJECTIVE The objective of the study was to identify interacting exosomal proteins in bladder cancer for future use in targeted therapy. METHODS The Exocarta database (www.exocarta.org) was mined for urinary bladder cancer specific exosomal proteins. The urinary bladder cancer specific exosomal proteins (n=248) were analyzed to identify enriched pathways by Onto-tool Pathway Express (http://vortex.cs.wayne.edu/ontoexpress). RESULTS Enriched pathways included cellular architecture, motility, cell to cell adhesion, tumorigenesis and metastasis. Proteins in the 9 top-ranked pathways included CTNNA1 (alpha-catenin), CTNNB1 (beta-catenin), VSAP, ITGA4, PAK1, DDR1, CDC42, RHOA, NRAS, RHO, PIK3AR1, MLC1, MMRN1, and CTTNBP2 and network analysis revealed 10 important hub proteins and identified inferred interactor NF2. CONCLUSIONS The importance of identifying interactors is that that they can be used as targets for therapy, for example, using Bevacizumab (avastin--an angiogenesis inhibitor) against NF2 to inhibit protein-protein interactions will inhibit tumor growth and progression by hindering the exosome biogenesis.
Collapse
Affiliation(s)
- Nitu Kumari
- National Institute of Pathology, Indian Council of Medical Research, New Delhi 110029, India.
| | - Sunita Saxena
- National Institute of Pathology, Indian Council of Medical Research, New Delhi 110029, India
| | - Usha Agrawal
- National Institute of Pathology, Indian Council of Medical Research, New Delhi 110029, India.
| |
Collapse
|
39
|
Huq A, Kentwell M, Tirimacco A, Rossini J, Rawlings L, Winship I. Vestibular schwannoma in a patient with neurofibromatosis type 1: clinical report and literature review. Fam Cancer 2014; 14:157-60. [PMID: 25362541 DOI: 10.1007/s10689-014-9763-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We describe a young patient with typical neurofibromatosis type 1 on the basis of a mutation in the NF1 gene, who was diagnosed with a unilateral vestibular schwannoma caused by a somatic mutation in the NF2 gene. This combination has not been described before. This report highlights the requirement for ongoing surveillance regarding other manifestations of neurofibromatosis type 2 in such patients, as mosaicism cannot be ruled out. In addition to the NF1 mutation, the NF2 mutation should be considered in such cases if pre-implantation genetic diagnosis in undertaken.
Collapse
Affiliation(s)
- Aamira Huq
- Clinical Genetics and Familial Cancer Centre, The Royal Melbourne Hospital, University of Melbourne, Parkville, Australia,
| | | | | | | | | | | |
Collapse
|
40
|
Van-Gils J, Harambat J, Jubert C, Vidaud D, Llanas B, Perel Y, Lacombe D, Goizet C. Atypical hematologic and renal manifestations in Neurofibromatosis type I: Coincidence or pathophysiological link? Eur J Med Genet 2014; 57:639-42. [DOI: 10.1016/j.ejmg.2014.09.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 09/07/2014] [Indexed: 10/24/2022]
|
41
|
Next-generation sequencing identifies rare variants associated with Noonan syndrome. Proc Natl Acad Sci U S A 2014; 111:11473-8. [PMID: 25049390 DOI: 10.1073/pnas.1324128111] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Noonan syndrome (NS) is a relatively common genetic disorder, characterized by typical facies, short stature, developmental delay, and cardiac abnormalities. Known causative genes account for 70-80% of clinically diagnosed NS patients, but the genetic basis for the remaining 20-30% of cases is unknown. We performed next-generation sequencing on germ-line DNA from 27 NS patients lacking a mutation in the known NS genes. We identified gain-of-function alleles in Ras-like without CAAX 1 (RIT1) and mitogen-activated protein kinase kinase 1 (MAP2K1) and previously unseen loss-of-function variants in RAS p21 protein activator 2 (RASA2) that are likely to cause NS in these patients. Expression of the mutant RASA2, MAP2K1, or RIT1 alleles in heterologous cells increased RAS-ERK pathway activation, supporting a causative role in NS pathogenesis. Two patients had more than one disease-associated variant. Moreover, the diagnosis of an individual initially thought to have NS was revised to neurofibromatosis type 1 based on an NF1 nonsense mutation detected in this patient. Another patient harbored a missense mutation in NF1 that resulted in decreased protein stability and impaired ability to suppress RAS-ERK activation; however, this patient continues to exhibit a NS-like phenotype. In addition, a nonsense mutation in RPS6KA3 was found in one patient initially diagnosed with NS whose diagnosis was later revised to Coffin-Lowry syndrome. Finally, we identified other potential candidates for new NS genes, as well as potential carrier alleles for unrelated syndromes. Taken together, our data suggest that next-generation sequencing can provide a useful adjunct to RASopathy diagnosis and emphasize that the standard clinical categories for RASopathies might not be adequate to describe all patients.
Collapse
|
42
|
Jo YH, Kim HO, Song HR, Yoon KS. Identification of the NF1 gene mutation in Korean families with neurofibromatosis type 1. Genes Genomics 2014. [DOI: 10.1007/s13258-013-0132-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
43
|
Lee KM, Hwang SK, Lee JA. Neuronal autophagy and neurodevelopmental disorders. Exp Neurobiol 2013; 22:133-42. [PMID: 24167408 PMCID: PMC3807000 DOI: 10.5607/en.2013.22.3.133] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 09/12/2013] [Accepted: 09/12/2013] [Indexed: 12/15/2022] Open
Abstract
Neurodevelopmental disorders include a wide range of diseases such as autism spectrum disorders and mental retardation. Mutations in several genes that regulate neural development and synapse function have been identified in neurodevelopmental disorders. Interestingly, some affected genes and pathways in these diseases are associated with the autophagy pathway. Autophagy is a complex, bulky degradative process that involves the sequestration of cellular proteins, RNA, lipids, and cellular organelles into lysosomes. Despite recent progress in elucidating the genetics and molecular pathogenesis of these disorders, little is known about the pathogenic mechanisms and autophagy-related pathways involved in common neurodevelopmental disorders. Therefore, in this review, we focus on the current understanding of neuronal autophagy as well as recent findings on genetics and the roles of autophagy pathway in common neurodevelopmental disorders.
Collapse
Affiliation(s)
- Kyung-Min Lee
- Department of Anatomy, Graduate School of Medicine, Kyungpook National University, Daegu 700-422, Korea
| | | | | |
Collapse
|
44
|
Nemethova M, Bolcekova A, Ilencikova D, Durovcikova D, Hlinkova K, Hlavata A, Kovacs L, Kadasi L, Zatkova A. Thirty-nine novel neurofibromatosis 1 (NF1) gene mutations identified in Slovak patients. Ann Hum Genet 2013; 77:364-79. [PMID: 23758643 DOI: 10.1111/ahg.12026] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 04/22/2013] [Indexed: 01/20/2023]
Abstract
We performed a complex analysis of the neurofibromatosis type 1 (NF1) gene in Slovakia based on direct cDNA sequencing supplemented by multiple ligation dependent probe amplification (MLPA) analysis. All 108 patients had café-au-lait spots, 85% had axilary and/or inguinal freckling, 61% neurofibromas, 36% Lisch nodules of the iris and 31% optic pathway glioma, 5% suffered from typical skeletal disorders, and 51% of patients had family members with NF1. In 78 of the 86 (90.7%) index patients our analysis revealed the presence of NF1 mutations, 68 of which were small changes (87.2%), including 39 (50%) novel. Among the identified mutations the most prevalent were small deletions and insertions causing frameshift (42.3%), followed by nonsense (14.1%), missense (12.8%), and typical splicing (11.5%) mutations. Type 1 NF1 deletions and intragenic deletions/duplication were identified in five cases each (6.4%). Interestingly, in five other cases nontypical splicing variants were found, whose real effect on NF1 transcript would have remained undetected if using a DNA-based method alone, thus underlying the advantage of using the cDNA-based sequencing. We show that Slovak NF1 patients have a similar repertoire of NF1 germline mutations compared to other populations, with some prevalence of small deletions/insertions and a decreased proportion of nonsense mutations.
Collapse
Affiliation(s)
- Martina Nemethova
- Laboratory of Genetics, Institute of Molecular Physiology and Genetics, Bratislava, Slovakia
| | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Abstract
Small GTPases use GDP/GTP alternation to actuate a variety of functional switches that are pivotal for cell dynamics. The GTPase switch is turned on by GEFs, which stimulate dissociation of the tightly bound GDP, and turned off by GAPs, which accelerate the intrinsically sluggish hydrolysis of GTP. For Ras, Rho, and Rab GTPases, this switch incorporates a membrane/cytosol alternation regulated by GDIs and GDI-like proteins. The structures and core mechanisms of representative members of small GTPase regulators from most families have now been elucidated, illuminating their general traits combined with scores of unique features. Recent studies reveal that small GTPase regulators have themselves unexpectedly sophisticated regulatory mechanisms, by which they process cellular signals and build up specific cell responses. These mechanisms include multilayered autoinhibition with stepwise release, feedback loops mediated by the activated GTPase, feed-forward signaling flow between regulators and effectors, and a phosphorylation code for RhoGDIs. The flipside of these highly integrated functions is that they make small GTPase regulators susceptible to biochemical abnormalities that are directly correlated with diseases, notably a striking number of missense mutations in congenital diseases, and susceptible to bacterial mimics of GEFs, GAPs, and GDIs that take command of small GTPases in infections. This review presents an overview of the current knowledge of these many facets of small GTPase regulation.
Collapse
Affiliation(s)
- Jacqueline Cherfils
- Laboratoire d’Enzymologie et Biochimie Structurales, Centre National de la Recherche Scientifique, Centre deRecherche de Gif, Gif-sur-Yvette, France
| | | |
Collapse
|
46
|
Thomas L, Richards M, Mort M, Dunlop E, Cooper DN, Upadhyaya M. Assessment of the potential pathogenicity of missense mutations identified in the GTPase-activating protein (GAP)-related domain of the neurofibromatosis type-1 (NF1) gene. Hum Mutat 2012; 33:1687-96. [PMID: 22807134 DOI: 10.1002/humu.22162] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 06/28/2012] [Indexed: 11/09/2022]
Abstract
Neurofibromatosis type-1 (NF1) is caused by constitutional mutations of the NF1 tumor-suppressor gene. Although ∼85% of inherited NF1 microlesions constitute truncating mutations, the remaining ∼15% are missense mutations whose pathological relevance is often unclear. The GTPase-activating protein-related domain (GRD) of the NF1-encoded protein, neurofibromin, serves to define its major function as a negative regulator of the Ras-MAPK (mitogen-activated protein kinase) signaling pathway. We have established a functional assay to assess the potential pathogenicity of 15 constitutional nonsynonymous NF1 missense mutations (11 novel and 4 previously reported but not functionally characterized) identified in the NF1-GRD (p.R1204G, p.R1204W, p.R1276Q, p.L1301R, p.I1307V, p.T1324N, p.E1327G, p.Q1336R, p.E1356G, p.R1391G, p.V1398D, p.K1409E, p.P1412R, p.K1436Q, p.S1463F). Individual mutations were introduced into an NF1-GRD expression vector and activated Ras was assayed by an enzyme-linked immunosorbent assay (ELISA). Ten NF1-GRD variants were deemed to be potentially pathogenic by virtue of significantly elevated levels of activated GTP-bound Ras in comparison to wild-type NF1 protein. The remaining five NF1-GRD variants were deemed less likely to be of pathological significance as they exhibited similar levels of activated Ras to the wild-type protein. These conclusions received broad support from both bioinformatic analysis and molecular modeling and serve to improve our understanding of NF1-GRD structure and function.
Collapse
Affiliation(s)
- Laura Thomas
- Institute of Medical Genetics, Cardiff University, Cardiff, UK
| | | | | | | | | | | |
Collapse
|
47
|
Chabernaud C, Mennes M, Kardel PG, Gaillard WD, Kalbfleisch ML, Vanmeter JW, Packer RJ, Milham MP, Castellanos FX, Acosta MT. Lovastatin regulates brain spontaneous low-frequency brain activity in neurofibromatosis type 1. Neurosci Lett 2012; 515:28-33. [PMID: 22433254 DOI: 10.1016/j.neulet.2012.03.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 02/18/2012] [Accepted: 03/05/2012] [Indexed: 12/25/2022]
Abstract
In the neurofibromatosis type 1 (NF1) mouse model, lovastatin, used clinically for hypercholesterolemia, improves cognitive dysfunction. While such impairment has been studied in NF1, the neural substrates remain unclear. The aim of this imaging add-on to a Phase 1 open-label trial was to examine the effect of lovastatin on Default Network (DN) resting state functional connectivity (RSFC). Seven children with NF1 (aged 11.9 ± 2.2; 1 female) were treated with lovastatin once daily for 12 weeks. A 7-min 3-T echo-planar-imaging scan was collected one day before beginning treatment (off-drug) and the last day of treatment (on-drug) while performing a flanker task. After regressing-out task-associated variance, we used the residual time series as "continuous resting-state data" for RSFC analyses using 11 DN regions of interest. For qualitative comparisons, we included a group of 19 typically developing children (TDC) collected elsewhere. In the on-drug condition, lovastatin increased long-range positive RSFC within DN core regions (i.e., anterior medial prefrontal cortex and posterior cingulate cortex, PCC). In addition, lovastatin produced less diffuse local RSFC in the dorsomedial prefrontal cortex and PCC. The pattern of RSFC observed in the NF1 participants when on-drug closely resembled the RSFC patterns exhibited by the TDC. Lovastatin administration in this open trial regulated anterior-posterior long-range and local RSFC within the DN. These preliminary results are consistent with a role for lovastatin in normalization of developmental processes and with apparent benefits in a mouse NF1 model.
Collapse
Affiliation(s)
- Camille Chabernaud
- Phyllis Green and Randolph Cowen Institute for Pediatric Neuroscience at the New York University Langone Medical Center, 215 Lexington Avenue, New York, NY 10016, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Detjen AK, Tinschert S, Kaufmann D, Algermissen B, Nürnberg P, Schuelke M. Analysis of Mitochondrial DNA in Discordant Monozygotic Twins With Neurofibromatosis Type 1. Twin Res Hum Genet 2012; 10:486-95. [PMID: 17564507 DOI: 10.1375/twin.10.3.486] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
AbstractNeurofibromatosis type 1 (NF1) is the most frequent neurocutaneous disorder with autosomal dominant inheritance. Phenotype variability is high ranging from merely several café-au-lait spots to malignant peripheral nerve sheath tumors or severe disfigurement through plexiform neurofibromas. Identification of genetic factors that modify the NF1 phenotype would contribute to the understanding of NF1 pathophysiology and improve patient counselling. As even monozygotic (MZ) twins with NF1 may differ phenotypically, we wondered whether these variations might be inherited in a non-Mendelian fashion. Mitochondrial DNA (mtDNA) is inherited extrachromosomally through the cytoplasm of the oocyte and often harbours heteroplasmic sequence variations. At the time of blastomere separation, these variants may be skewedly distributed and effect phenotypic differences. Because of their co-localization with the tumor suppressor protein neurofibromin, which is mutated in NF1, mitochondria were particular attractive candidates for investigation. MtDNA was extracted from nucleated blood cells of four pairs of discordant MZ twins with NF1 and from cutaneous neurofibromas of one twin pair. We sequenced the entire mitochondrial genome and determined the state of heteroplasmy by investigating a microsatellite region of the mitochondrial D-loop (D310-tract). The clinical diagnosis was confirmed in all patients by detection of pathogenic mutations in the NF1 gene. Monozygosity was verified by genotyping. However, we did not detect evidence for mtDNA sequence differences or for different degrees of heteroplasmy between individuals of the same twin pair. The phenotypic discordance of MZ twins with NF1 cannot be explained by skewed distribution of mtDNA mutations or polymorphisms.
Collapse
Affiliation(s)
- Anne Katrin Detjen
- Department of Neuropediatrics, Charité, University Medical Center, Berlin, Germany
| | | | | | | | | | | |
Collapse
|
49
|
El-Hoss J, Sullivan K, Cheng T, Yu NYC, Bobyn JD, Peacock L, Mikulec K, Baldock P, Alexander IE, Schindeler A, Little DG. A murine model of neurofibromatosis type 1 tibial pseudarthrosis featuring proliferative fibrous tissue and osteoclast-like cells. J Bone Miner Res 2012; 27:68-78. [PMID: 21956219 DOI: 10.1002/jbmr.528] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 09/14/2011] [Accepted: 09/22/2011] [Indexed: 11/07/2022]
Abstract
Neurofibromatosis type 1 (NF1) is a common genetic condition caused by mutations in the NF1 gene. Patients often suffer from tissue-specific lesions associated with local double-inactivation of NF1. In this study, we generated a novel fracture model to investigate the mechanism underlying congenital pseudarthrosis of the tibia (CPT) associated with NF1. We used a Cre-expressing adenovirus (AdCre) to inactivate Nf1 in vitro in cultured osteoprogenitors and osteoblasts, and in vivo in the fracture callus of Nf1(flox/flox) and Nf1(flox/-) mice. The effects of the presence of Nf1(null) cells were extensively examined. Cultured Nf1(null)-committed osteoprogenitors from neonatal calvaria failed to differentiate and express mature osteoblastic markers, even with recombinant bone morphogenetic protein-2 (rhBMP-2) treatment. Similarly, Nf1(null)-inducible osteoprogenitors obtained from Nf1 MyoDnull mouse muscle were also unresponsive to rhBMP-2. In both closed and open fracture models in Nf1(flox/flox) and Nf1(flox/-) mice, local AdCre injection significantly impaired bone healing, with fracture union being <50% that of wild type controls. No significant difference was seen between Nf1(flox/flox) and Nf1(flox/-) mice. Histological analyses showed invasion of the Nf1(null) fractures by fibrous and highly proliferative tissue. Mean amounts of fibrous tissue were increased upward of 10-fold in Nf1(null) fractures and bromodeoxyuridine (BrdU) staining in closed fractures showed increased numbers of proliferating cells. In Nf1(null) fractures, tartrate-resistant acid phosphatase-positive (TRAP+) cells were frequently observed within the fibrous tissue, not lining a bone surface. In summary, we report that local Nf1 deletion in a fracture callus is sufficient to impair bony union and recapitulate histological features of clinical CPT. Cell culture findings support the concept that Nf1 double inactivation impairs early osteoblastic differentiation. This model provides valuable insight into the pathobiology of the disease, and will be helpful for trialing therapeutic compounds.
Collapse
Affiliation(s)
- Jad El-Hoss
- Kids Research Institute, Orthopaedic Research and Biotechnology, Westmead, Australia.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Ligeti E, Welti S, Scheffzek K. Inhibition and Termination of Physiological Responses by GTPase Activating Proteins. Physiol Rev 2012; 92:237-72. [DOI: 10.1152/physrev.00045.2010] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Physiological processes are strictly organized in space and time. However, in cell physiology research, more attention is given to the question of space rather than to time. To function as a signal, environmental changes must be restricted in time; they need not only be initiated but also terminated. In this review, we concentrate on the role of one specific protein family involved in biological signal termination. GTPase activating proteins (GAPs) accelerate the endogenously low GTP hydrolysis rate of monomeric guanine nucleotide-binding proteins (GNBPs), limiting thereby their prevalence in the active, GTP-bound form. We discuss cases where defective or excessive GAP activity of specific proteins causes significant alteration in the function of the nervous, endocrine, and hemopoietic systems, or contributes to development of infections and tumors. Biochemical and genetic data as well as observations from human pathology support the notion that GAPs represent vital elements in the spatiotemporal fine tuning of physiological processes.
Collapse
Affiliation(s)
- Erzsébet Ligeti
- Department of Physiology, Semmelweis University, Budapest, Hungary; Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany; and Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Stefan Welti
- Department of Physiology, Semmelweis University, Budapest, Hungary; Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany; and Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Klaus Scheffzek
- Department of Physiology, Semmelweis University, Budapest, Hungary; Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany; and Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| |
Collapse
|