1
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Bjorklund GR, Rees KP, Balasubramanian K, Hewitt LT, Nishimura K, Newbern JM. Hyperactivation of MEK1 in cortical glutamatergic neurons results in projection axon deficits and aberrant motor learning. Dis Model Mech 2024; 17:dmm050570. [PMID: 38826084 PMCID: PMC11247507 DOI: 10.1242/dmm.050570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 05/21/2024] [Indexed: 06/04/2024] Open
Abstract
Abnormal extracellular signal-regulated kinase 1/2 (ERK1/2, encoded by Mapk3 and Mapk1, respectively) signaling is linked to multiple neurodevelopmental diseases, especially the RASopathies, which typically exhibit ERK1/2 hyperactivation in neurons and non-neuronal cells. To better understand how excitatory neuron-autonomous ERK1/2 activity regulates forebrain development, we conditionally expressed a hyperactive MEK1 (MAP2K1) mutant, MEK1S217/221E, in cortical excitatory neurons of mice. MEK1S217/221E expression led to persistent hyperactivation of ERK1/2 in cortical axons, but not in soma/nuclei. We noted reduced axonal arborization in multiple target domains in mutant mice and reduced the levels of the activity-dependent protein ARC. These changes did not lead to deficits in voluntary locomotion or accelerating rotarod performance. However, skilled motor learning in a single-pellet retrieval task was significantly diminished in these MEK1S217/221E mutants. Restriction of MEK1S217/221E expression to layer V cortical neurons recapitulated axonal outgrowth deficits but did not affect motor learning. These results suggest that cortical excitatory neuron-autonomous hyperactivation of MEK1 is sufficient to drive deficits in axon outgrowth, which coincide with reduced ARC expression, and deficits in skilled motor learning. Our data indicate that neuron-autonomous decreases in long-range axonal outgrowth may be a key aspect of neuropathogenesis in RASopathies.
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Affiliation(s)
- George R. Bjorklund
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ 85287, USA
| | - Katherina P. Rees
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | | | - Lauren T. Hewitt
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Kenji Nishimura
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Jason M. Newbern
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
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2
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Cristobal CD, Lee HK. Development of myelinating glia: An overview. Glia 2022; 70:2237-2259. [PMID: 35785432 PMCID: PMC9561084 DOI: 10.1002/glia.24238] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/24/2022] [Accepted: 06/24/2022] [Indexed: 01/07/2023]
Abstract
Myelin is essential to nervous system function, playing roles in saltatory conduction and trophic support. Oligodendrocytes (OLs) and Schwann cells (SCs) form myelin in the central and peripheral nervous systems respectively and follow different developmental paths. OLs are neural stem-cell derived and follow an intrinsic developmental program resulting in a largely irreversible differentiation state. During embryonic development, OL precursor cells (OPCs) are produced in distinct waves originating from different locations in the central nervous system, with a subset developing into myelinating OLs. OPCs remain evenly distributed throughout life, providing a population of responsive, multifunctional cells with the capacity to remyelinate after injury. SCs derive from the neural crest, are highly dependent on extrinsic signals, and have plastic differentiation states. SC precursors (SCPs) are produced in early embryonic nerve structures and differentiate into multipotent immature SCs (iSCs), which initiate radial sorting and differentiate into myelinating and non-myelinating SCs. Differentiated SCs retain the capacity to radically change phenotypes in response to external signals, including becoming repair SCs, which drive peripheral regeneration. While several transcription factors and myelin components are common between OLs and SCs, their differentiation mechanisms are highly distinct, owing to their unique lineages and their respective environments. In addition, both OLs and SCs respond to neuronal activity and regulate nervous system output in reciprocal manners, possibly through different pathways. Here, we outline their basic developmental programs, mechanisms regulating their differentiation, and recent advances in the field.
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Affiliation(s)
- Carlo D. Cristobal
- Integrative Program in Molecular and Biomedical SciencesBaylor College of MedicineHoustonTexasUSA,Jan and Dan Duncan Neurological Research InstituteTexas Children's HospitalHoustonTexasUSA
| | - Hyun Kyoung Lee
- Integrative Program in Molecular and Biomedical SciencesBaylor College of MedicineHoustonTexasUSA,Jan and Dan Duncan Neurological Research InstituteTexas Children's HospitalHoustonTexasUSA,Department of PediatricsBaylor College of MedicineHoustonTexasUSA,Department of NeuroscienceBaylor College of MedicineHoustonTexasUSA
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3
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Talley MJ, Nardini D, Shabbir N, Ehrman LA, Prada CE, Waclaw RR. Generation of a Mouse Model to Study the Noonan Syndrome Gene Lztr1 in the Telencephalon. Front Cell Dev Biol 2021; 9:673995. [PMID: 34222248 PMCID: PMC8242193 DOI: 10.3389/fcell.2021.673995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 05/07/2021] [Indexed: 12/28/2022] Open
Abstract
The leucine zipper-like transcriptional regulator 1 (Lztr1) is a BTB-Kelch domain protein involved in RAS/MAPK pathway regulation. Mutations in LZTR1 are associated with cancers and Noonan syndrome, the most common RASopathy. The expression and function of Lztr1 in the developing brain remains poorly understood. Here we show that Lztr1 is expressed in distinct regions of the telencephalon, the most anterior region of the forebrain. Lztr1 expression was robust in the cortex, amygdala, hippocampus, and oligodendrocytes in the white matter. To gain insight into the impact of Lztr1 deficiency, we generated a conditional knockout (cKO) restricted to the telencephalon using Foxg1IREScre/+. Lztr1 cKOs are viable to postnatal stages and show reduced Lztr1 expression in the telencephalon. Interestingly, Lztr1 cKOs exhibit an increase in MAPK pathway activation in white matter regions and subsequently show an altered expression of stage-specific markers in the oligodendrocyte lineage with increased oligodendrocyte progenitor cells (OPCs) and decreased markers of oligodendrocyte differentiation. Moreover, Lztr1 cKOs also exhibit an increased expression of the astrocyte marker GFAP. These results highlight the generation of a new mouse model to study Lztr1 deficiency in the brain and reveal a novel role for Lztr1 in normal oligodendrocyte and astrocyte development in the telencephalon.
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Affiliation(s)
- Mary Jo Talley
- Graduate Program in Molecular and Developmental Biology, Cincinnati Children's Hospital Research Foundation, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Diana Nardini
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Nisha Shabbir
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Lisa A Ehrman
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Carlos E Prada
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Ronald R Waclaw
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States.,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
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4
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Talley MJ, Nardini D, Qin S, Prada CE, Ehrman LA, Waclaw RR. A role for sustained MAPK activity in the mouse ventral telencephalon. Dev Biol 2021; 476:137-147. [PMID: 33775695 DOI: 10.1016/j.ydbio.2021.03.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 03/14/2021] [Accepted: 03/21/2021] [Indexed: 11/28/2022]
Abstract
The MAPK pathway is a major growth signal that has been implicated during the development of progenitors, neurons, and glia in the embryonic brain. Here, we show that the MAPK pathway plays an important role in the generation of distinct cell types from progenitors in the ventral telencephalon. Our data reveal that phospho-p44/42 (called p-ERK1/2) and the ETS transcription factor Etv5, both downstream effectors in the MAPK pathway, show a regional bias in expression during ventral telencephalic development, with enriched expression in the dorsal region of the LGE and ventral region of the MGE at E13.5 and E15.5. Interestingly, expression of both factors becomes more uniform in ventricular zone (VZ) progenitors by E18.5. To gain insight into the role of MAPK activity during progenitor cell development, we used a cre inducible constitutively active MEK1 allele (RosaMEK1DD/+) in combination with a ventral telencephalon enriched cre (Gsx2e-cre) or a dorsal telencephalon enriched cre (Emx1cre/+). Sustained MEK/MAPK activity in the ventral telencephalon (Gsx2e-cre; RosaMEK1DD/+) expanded dorsal lateral ganglionic eminence (dLGE) enriched genes (Gsx2 and Sp8) and oligodendrocyte progenitor cell (OPC) markers (Olig2, Pdgfrα, and Sox10), and also reduced markers in the ventral (v) LGE domain (Isl1 and Foxp1). Activation of MEK/MAPK activity in the dorsal telencephalon (Emx1cre/+; RosaMEK1DD/+) did not initially activate the expression of dLGE or OPC genes at E15.5 but ectopic expression of Gsx2 and OPC markers were observed at E18.5. These results support the idea that MAPK activity as readout by p-ERK1/2 and Etv5 expression is enriched in distinct subdomains of ventral telencephalic progenitors during development. In addition, sustained activation of the MEK/MAPK pathway in the ventral or dorsal telencephalon influences dLGE and OPC identity from progenitors.
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Affiliation(s)
- Mary Jo Talley
- Graduate Program in Molecular and Developmental Biology, Cincinnati Children's Hospital Research Foundation, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Diana Nardini
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Shenyue Qin
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Carlos E Prada
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Lisa A Ehrman
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Ronald R Waclaw
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA; Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.
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5
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Joerger-Messerli MS, Thomi G, Haesler V, Keller I, Renz P, Surbek DV, Schoeberlein A. Human Wharton's Jelly Mesenchymal Stromal Cell-Derived Small Extracellular Vesicles Drive Oligodendroglial Maturation by Restraining MAPK/ERK and Notch Signaling Pathways. Front Cell Dev Biol 2021; 9:622539. [PMID: 33869172 PMCID: PMC8044995 DOI: 10.3389/fcell.2021.622539] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 02/28/2021] [Indexed: 12/12/2022] Open
Abstract
Peripartum cerebral hypoxia and ischemia, and intrauterine infection and inflammation, are detrimental for the precursor cells of the myelin-forming oligodendrocytes in the prematurely newborn, potentially leading to white matter injury (WMI) with long-term neurodevelopmental sequelae. Previous data show that hypomyelination observed in WMI is caused by arrested oligodendroglial maturation rather than oligodendrocyte-specific cell death. In a rat model of premature WMI, we have recently shown that small extracellular vesicles (sEV) derived from Wharton's jelly mesenchymal stromal cells (WJ-MSC) protect from myelination deficits. Thus, we hypothesized that sEV derived from WJ-MSC directly promote oligodendroglial maturation in oligodendrocyte precursor cells. To test this assumption, sEV were isolated from culture supernatants of human WJ-MSC by ultracentrifugation and co-cultured with the human immortalized oligodendrocyte precursor cell line MO3.13. As many regulatory functions in WMI have been ascribed to microRNA (miR) and as sEV are carriers of functional miR which can be delivered to target cells, we characterized and quantified the miR content of WJ-MSC-derived sEV by next-generation sequencing. We found that WJ-MSC-derived sEV co-localized with MO3.13 cells within 4 h. After 5 days of co-culture, the expression of myelin basic protein (MBP), a marker for mature oligodendrocytes, was significantly increased, while the oligodendrocyte precursor marker platelet-derived growth factor alpha (PDGFRα) was decreased. Notch and MAPK/ERK pathways known to inhibit oligodendrocyte maturation and differentiation were significantly reduced. The pathway enrichment analysis showed that the miR present in WJ-MSC-derived sEV target genes having key roles in the MAPK pathway. Our data strongly suggest that sEV from WJ-MSC directly drive the maturation of oligodendrocyte precursor cells by repressing Notch and MAPK/ERK signaling.
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Affiliation(s)
- Marianne S Joerger-Messerli
- Department of Obstetrics and Feto-maternal Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.,Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Gierin Thomi
- Department of Obstetrics and Feto-maternal Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.,Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Valérie Haesler
- Department of Obstetrics and Feto-maternal Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.,Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Irene Keller
- Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland.,Swiss Institute of Bioinformatics, University of Bern, Bern, Switzerland
| | - Patricia Renz
- Department of Obstetrics and Feto-maternal Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.,Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Daniel V Surbek
- Department of Obstetrics and Feto-maternal Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.,Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Andreina Schoeberlein
- Department of Obstetrics and Feto-maternal Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.,Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
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6
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Zhang T, Guan P, Liu W, Zhao G, Fang Y, Fu H, Gui JF, Li G, Liu JX. Copper stress induces zebrafish central neural system myelin defects via WNT/NOTCH-hoxb5b signaling and pou3f1/fam168a/fam168b DNA methylation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194612. [PMID: 32745624 DOI: 10.1016/j.bbagrm.2020.194612] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 07/18/2020] [Accepted: 07/27/2020] [Indexed: 12/21/2022]
Abstract
Unbalanced copper (Cu) homeostasis is associated with neurological development defects and diseases. However, the molecular mechanisms remain elusive. Here, central neural system (CNS) myelin defects and the down-regulated expression of WNT/NOTCH signaling and its down-stream mediator hoxb5b were observed in Cu2+ stressed zebrafish larvae. The loss/knockdown-of-function of hoxb5b phenocopied the myelin and axon defects observed in Cu2+ stressed embryos. Meanwhile, the activation of WNT/NOTCH signaling and ectopic expression of hoxb5b could rescue Cu induced myelin defects. Additionally, fam168b, similar to pou3f1/2, exhibited significant promoter hypermethylation and reduced expression in Cu2+ stressed embryos. The hypermethylated locus in fam168b promoter acted pivotally in its transcription, and the loss/knockdown of fam168b/pou3f1 also induced myelin defects. This study also demonstrated that fam168b/pou3f1 and hoxb5b axis acted in a seesaw manner during fish embryogenesis: Cu induced the down-regulated expression of the WNT&NOTCH-hoxb5b axis through the function of copper transporter cox17, coupled with the promoter methylation of genes fam168b/pou3f1, and its subsequent down-regulated expression through the function of another transporter atp7b, making joint contributions to myelin defects in embryos.
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Affiliation(s)
- Ting Zhang
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
| | - PengPeng Guan
- College of Informatics, Agricultural Bioinformatics Key Laboratory of Hubei Province, Hubei Engineering Technology Research Center of Agricultural Big Data, Huazhong Agricultural University, Wuhan 430070, China
| | - WenYe Liu
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China
| | - Guang Zhao
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China
| | - YaPing Fang
- College of Informatics, Agricultural Bioinformatics Key Laboratory of Hubei Province, Hubei Engineering Technology Research Center of Agricultural Big Data, Huazhong Agricultural University, Wuhan 430070, China
| | - Hui Fu
- Department of Anatomy, School of Basic Medical Science, Wuhan University, Wuhan 430072, China
| | - Jian-Fang Gui
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - GuoLiang Li
- College of Informatics, Agricultural Bioinformatics Key Laboratory of Hubei Province, Hubei Engineering Technology Research Center of Agricultural Big Data, Huazhong Agricultural University, Wuhan 430070, China.
| | - Jing-Xia Liu
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China.
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7
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Gripp KW, Schill L, Schoyer L, Stronach B, Bennett AM, Blaser S, Brown A, Burdine R, Burkitt-Wright E, Castel P, Darilek S, Dias A, Dyer T, Ellis M, Erickson G, Gelb BD, Green T, Gross A, Ho A, Holder JL, Inoue SI, Jelin AC, Kennedy A, Klein R, Kontaridis MI, Magoulas P, McConnell DB, McCormick F, Neel BG, Prada CE, Rauen KA, Roberts A, Rodriguez-Viciana P, Rosen N, Rumbaugh G, Sablina A, Solman M, Tartaglia M, Thomas A, Timmer WC, Venkatachalam K, Walsh KS, Wolters PL, Yi JS, Zenker M, Ratner N. The sixth international RASopathies symposium: Precision medicine-From promise to practice. Am J Med Genet A 2019; 182:597-606. [PMID: 31825160 DOI: 10.1002/ajmg.a.61434] [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] [Received: 10/29/2019] [Accepted: 11/05/2019] [Indexed: 12/19/2022]
Abstract
The RASopathies are a group of genetic disorders that result from germline pathogenic variants affecting RAS-mitogen activated protein kinase (MAPK) pathway genes. RASopathies share RAS/MAPK pathway dysregulation and share phenotypic manifestations affecting numerous organ systems, causing lifelong and at times life-limiting medical complications. RASopathies may benefit from precision medicine approaches. For this reason, the Sixth International RASopathies Symposium focused on exploring precision medicine. This meeting brought together basic science researchers, clinicians, clinician scientists, patient advocates, and representatives from pharmaceutical companies and the National Institutes of Health. Novel RASopathy genes, variants, and animal models were discussed in the context of medication trials and drug development. Attempts to define and measure meaningful endpoints for treatment trials were discussed, as was drug availability to patients after trial completion.
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Affiliation(s)
- Karen W Gripp
- Al duPont Hospital for Children, Wilmington, Delaware
| | - Lisa Schill
- RASopathies Network USA, Altadena, California
| | | | | | | | - Susan Blaser
- Hospital for Sick Children, Toronto, Ontario, Canada
| | - Amanda Brown
- Noonan Syndrome Foundation, Farmington, Connecticut
| | | | - Emma Burkitt-Wright
- Manchester Centre for Genomic Medicine, Manchester University NHS Foundation Trust and University of Manchester, Manchester, UK
| | - Pau Castel
- UCSF, Helen Diller Family Comprehensive Cancer Center, San Francisco, California
| | | | - Alwyn Dias
- Bridge Group Consulting, Morristown, New Jersey
| | - Tuesdi Dyer
- CFC International, Saint Petersburg, Florida
| | | | | | - Bruce D Gelb
- Department of Pediatrics, Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, New York.,Department of Genetics and Genomic Sciences, Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | | | | | - Alan Ho
- Memorial Sloan Kettering Cancer Center, New York, New York
| | | | | | | | - Annie Kennedy
- Parent Project Muscular Dystrophy, Hackensack, New Jersey
| | | | | | | | | | - Frank McCormick
- UCSF, Helen Diller Family Comprehensive Cancer Center, San Francisco, California
| | - Benjamin G Neel
- Perlmutter Cancer Center and NYU School of Medicine, NYU Langone Health, New York, New York
| | - Carlos E Prada
- Cincinnati Children's Hospital Medical Center and University of Cincinnati, School of Medicine, Cincinnati, Ohio
| | - Katherine A Rauen
- Department of Pediatrics, Division of Genomic Medicine, University of California Davis, Sacramento, California
| | - Amy Roberts
- Department of Cardiology, Division of Genetics, Boston Children's Hospital, Boston, Massachusetts.,Department of Pediatrics, Division of Genetics, Boston Children's Hospital, Boston, Massachusetts
| | | | - Neal Rosen
- Memorial Sloan Kettering Cancer Center, New York, New York
| | | | - Anna Sablina
- VIB-KU Leuven Center for Cancer Biology, Leuven, Belgium
| | - Maja Solman
- Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù-IRCCS, Rome, Italy
| | | | | | - Kartik Venkatachalam
- McGovern Medical School, University of Texas Health Science Center, Houston, Texas
| | - Karin S Walsh
- Children's National Hospital & The George Washington School of Medicine, Washington, District of Columbia
| | - Pamela L Wolters
- Pediatric Oncology Branch, National Cancer Institute, Bethesda, Maryland
| | - Jae-Sung Yi
- Yale University School of Medicine, New Haven, Connecticut
| | - Martin Zenker
- University Hospital Magdeburg, Institute of Human Genetics, Magdeburg, Germany
| | - Nancy Ratner
- Cincinnati Children's Hospital Medical Center and University of Cincinnati, School of Medicine, Cincinnati, Ohio
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8
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Holter MC, Hewitt LT, Koebele SV, Judd JM, Xing L, Bimonte-Nelson HA, Conrad CD, Araki T, Neel BG, Snider WD, Newbern JM. The Noonan Syndrome-linked Raf1L613V mutation drives increased glial number in the mouse cortex and enhanced learning. PLoS Genet 2019; 15:e1008108. [PMID: 31017896 PMCID: PMC6502435 DOI: 10.1371/journal.pgen.1008108] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 05/06/2019] [Accepted: 03/22/2019] [Indexed: 12/19/2022] Open
Abstract
RASopathies are a family of related syndromes caused by mutations in regulators of the RAS/Extracellular Regulated Kinase 1/2 (ERK1/2) signaling cascade that often result in neurological deficits. RASopathy mutations in upstream regulatory components, such as NF1, PTPN11/SHP2, and RAS have been well-characterized, but mutation-specific differences in the pathogenesis of nervous system abnormalities remain poorly understood, especially those involving mutations downstream of RAS. Here, we assessed cellular and behavioral phenotypes in mice expressing a Raf1L613V gain-of-function mutation associated with the RASopathy, Noonan Syndrome. We report that Raf1L613V/wt mutants do not exhibit a significantly altered number of excitatory or inhibitory neurons in the cortex. However, we observed a significant increase in the number of specific glial subtypes in the forebrain. The density of GFAP+ astrocytes was significantly increased in the adult Raf1L613V/wt cortex and hippocampus relative to controls. OLIG2+ oligodendrocyte progenitor cells were also increased in number in mutant cortices, but we detected no significant change in myelination. Behavioral analyses revealed no significant changes in voluntary locomotor activity, anxiety-like behavior, or sociability. Surprisingly, Raf1L613V/wt mice performed better than controls in select aspects of the water radial-arm maze, Morris water maze, and cued fear conditioning tasks. Overall, these data show that increased astrocyte and oligodendrocyte progenitor cell (OPC) density in the cortex coincides with enhanced cognition in Raf1L613V/wt mutants and further highlight the distinct effects of RASopathy mutations on nervous system development and function. The RASopathies are a large and complex family of syndromes caused by mutations in the RAS/MAPK signaling cascade with no known cure. Individuals with these syndromes often present with heart defects, craniofacial differences, and neurological abnormalities, such as developmental delay, cognitive changes, epilepsy, and an increased risk of autism. However, there is wide variation in the extent of intellectual ability between individuals. It is currently unclear how different RASopathy mutations affect brain development. Here, we describe the cellular and behavioral consequences of a mutation in a gene called Raf1 that is associated with a common RASopathy, Noonan Syndrome. We find that mice harboring a mutation in Raf1 show moderate increases in the number of two subsets of glial cells, which is also observed in a number of other RASopathy brain samples. Surprisingly, we found that Raf1 mutant mice show improved performance in several learning and memory tasks. Our work highlights potential mutation-specific changes in RASopathy brain function and helps set the framework for future personalized therapeutic approaches.
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Affiliation(s)
- Michael C. Holter
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Lauren. T. Hewitt
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Stephanie V. Koebele
- Department of Psychology, Arizona State University, Tempe, Arizona, United States of America
- Arizona Alzheimer’s Consortium, Phoenix, Arizona, United States of America
| | - Jessica M. Judd
- Department of Psychology, Arizona State University, Tempe, Arizona, United States of America
| | - Lei Xing
- Neuroscience Center, The University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Heather A. Bimonte-Nelson
- Department of Psychology, Arizona State University, Tempe, Arizona, United States of America
- Arizona Alzheimer’s Consortium, Phoenix, Arizona, United States of America
| | - Cheryl D. Conrad
- Department of Psychology, Arizona State University, Tempe, Arizona, United States of America
| | - Toshiyuki Araki
- Laura and Isaac Perlmutter Cancer Center, New York University Langone Medical Center, New York, New York, United States of America
| | - Benjamin G. Neel
- Laura and Isaac Perlmutter Cancer Center, New York University Langone Medical Center, New York, New York, United States of America
| | - William D. Snider
- Neuroscience Center, The University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Jason M. Newbern
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- * E-mail:
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9
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Perspectives of RAS and RHEB GTPase Signaling Pathways in Regenerating Brain Neurons. Int J Mol Sci 2018; 19:ijms19124052. [PMID: 30558189 PMCID: PMC6321366 DOI: 10.3390/ijms19124052] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 12/05/2018] [Accepted: 12/13/2018] [Indexed: 12/29/2022] Open
Abstract
Cellular activation of RAS GTPases into the GTP-binding “ON” state is a key switch for regulating brain functions. Molecular protein structural elements of rat sarcoma (RAS) and RAS homolog protein enriched in brain (RHEB) GTPases involved in this switch are discussed including their subcellular membrane localization for triggering specific signaling pathways resulting in regulation of synaptic connectivity, axonal growth, differentiation, migration, cytoskeletal dynamics, neural protection, and apoptosis. A beneficial role of neuronal H-RAS activity is suggested from cellular and animal models of neurodegenerative diseases. Recent experiments on optogenetic regulation offer insights into the spatiotemporal aspects controlling RAS/mitogen activated protein kinase (MAPK) or phosphoinositide-3 kinase (PI3K) pathways. As optogenetic manipulation of cellular signaling in deep brain regions critically requires penetration of light through large distances of absorbing tissue, we discuss magnetic guidance of re-growing axons as a complementary approach. In Parkinson’s disease, dopaminergic neuronal cell bodies degenerate in the substantia nigra. Current human trials of stem cell-derived dopaminergic neurons must take into account the inability of neuronal axons navigating over a large distance from the grafted site into striatal target regions. Grafting dopaminergic precursor neurons directly into the degenerating substantia nigra is discussed as a novel concept aiming to guide axonal growth by activating GTPase signaling through protein-functionalized intracellular magnetic nanoparticles responding to external magnets.
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Serdar M, Herz J, Kempe K, Winterhager E, Jastrow H, Heumann R, Felderhoff-Müser U, Bendix I. Protection of Oligodendrocytes Through Neuronal Overexpression of the Small GTPase Ras in Hyperoxia-Induced Neonatal Brain Injury. Front Neurol 2018; 9:175. [PMID: 29619004 PMCID: PMC5871665 DOI: 10.3389/fneur.2018.00175] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 03/06/2018] [Indexed: 12/29/2022] Open
Abstract
Prematurely born infants are highly susceptible to various environmental factors, such as inflammation, drug exposure, and also high environmental oxygen concentrations. Hyperoxia induces perinatal brain injury affecting white and gray matter development. It is well known that mitogen-activated protein kinase signaling is involved in cell survival, proliferation, and differentiation. Therefore, we aim to elucidate cell-specific responses of neuronal overexpression of the small GTPase Ras on hyperoxia-mediated brain injury. Six-day-old (P6) synRas mice (neuronal Ras overexpression under the synapsin promoter) or wild-type littermates were kept under hyperoxia (80% oxygen) or room air (21% oxygen) for 24 h. Apoptosis was analyzed by Western blot of cleaved Caspase-3 and neuronal and oligodendrocyte degeneration via immunohistochemistry. Short-term differentiation capacity of oligodendrocytes was assessed by quantification of myelin basic protein expression at P11. Long-lasting changes of hyperoxia-induced alteration of myelin structures were evaluated via transmission electron microscopy in young adult animals (P42). Western blot analysis of active Caspase-3 demonstrates a significant upregulation in wild-type littermates exposed to hyperoxia whereas synRas mice did not show any marked alteration of cleaved Caspase-3 protein levels. Immunohistochemistry revealed a protective effect of neuronal Ras overexpression on neuron and oligodendrocyte survival. Hyperoxia-induced hypomyelination in wild-type littermates was restored in synRas mice. These short-term protective effects through promotion of neuronal survival translated into long-lasting improvement of ultrastructural alterations of myelin sheaths in mice with neuronal overexpression of Ras compared with hyperoxic wild-type mice. Our data suggest that transgenic increase of neuronal Ras activity in the immature brain results in secondary protection of oligodendrocytes from hyperoxia-induced white matter brain injury.
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Affiliation(s)
- Meray Serdar
- Department of Pediatrics I, Neonatology, University Hospital, University Duisburg-Essen, Essen, Germany
| | - Josephine Herz
- Department of Pediatrics I, Neonatology, University Hospital, University Duisburg-Essen, Essen, Germany
| | - Karina Kempe
- Department of Pediatrics I, Neonatology, University Hospital, University Duisburg-Essen, Essen, Germany
| | - Elke Winterhager
- Imaging Center Essen, EM Unit, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Holger Jastrow
- Imaging Center Essen, EM Unit, University Hospital Essen, University Duisburg-Essen, Essen, Germany.,Institute of Anatomy, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Rolf Heumann
- Biochemistry II, Molecular Neurobiochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Ursula Felderhoff-Müser
- Department of Pediatrics I, Neonatology, University Hospital, University Duisburg-Essen, Essen, Germany
| | - Ivo Bendix
- Department of Pediatrics I, Neonatology, University Hospital, University Duisburg-Essen, Essen, Germany
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Giacci MK, Bartlett CA, Huynh M, Kilburn MR, Dunlop SA, Fitzgerald M. Three dimensional electron microscopy reveals changing axonal and myelin morphology along normal and partially injured optic nerves. Sci Rep 2018; 8:3979. [PMID: 29507421 PMCID: PMC5838102 DOI: 10.1038/s41598-018-22361-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 02/22/2018] [Indexed: 12/21/2022] Open
Abstract
Following injury to the central nervous system, axons and myelin distinct from the initial injury site undergo changes associated with compromised function. Quantifying such changes is important to understanding the pathophysiology of neurotrauma; however, most studies to date used 2 dimensional (D) electron microscopy to analyse single sections, thereby failing to capture changes along individual axons. We used serial block face scanning electron microscopy (SBF SEM) to undertake 3D reconstruction of axons and myelin, analysing optic nerves from normal uninjured female rats and following partial optic nerve transection. Measures of axon and myelin dimensions were generated by examining 2D images at 5 µm intervals along the 100 µm segments. In both normal and injured animals, changes in axonal diameter, myelin thickness, fiber diameter, G-ratio and percentage myelin decompaction were apparent along the lengths of axons to varying degrees. The range of values for axon diameter along individual reconstructed axons in 3D was similar to the range from 2D datasets, encompassing reported variation in axonal diameter attributed to retinal ganglion cell diversity. 3D electron microscopy analyses have provided the means to demonstrate substantial variability in ultrastructure along the length of individual axons and to improve understanding of the pathophysiology of neurotrauma.
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Affiliation(s)
- Marcus K Giacci
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Perth, 6009, Western Australia, Australia
| | - Carole A Bartlett
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Perth, 6009, Western Australia, Australia
| | - Minh Huynh
- Australian Centre for Microscopy and Microanalysis, The University of Sydney, City Road, Sydney, 2006, New South Wales, Australia
| | - Matt R Kilburn
- Centre for Microscopy, Characterisation, and Analysis, The University of Western Australia, 35 Stirling Hwy, Perth, 6009, Western Australia, Australia
| | - Sarah A Dunlop
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Perth, 6009, Western Australia, Australia
| | - Melinda Fitzgerald
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Perth, 6009, Western Australia, Australia. .,Curtin Health Innovation Research Institute, Curtin University, Bentley, 6102, Western Australia, Australia. .,Perron Institute for Neurological and Translational Science, Sarich Neuroscience Research Institute, 8 Verdun St, Nedlands, 6009, Western Australia, Australia.
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