1
|
Frith TJR, Briscoe J, Boezio GLM. From signalling to form: the coordination of neural tube patterning. Curr Top Dev Biol 2023; 159:168-231. [PMID: 38729676 DOI: 10.1016/bs.ctdb.2023.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024]
Abstract
The development of the vertebrate spinal cord involves the formation of the neural tube and the generation of multiple distinct cell types. The process starts during gastrulation, combining axial elongation with specification of neural cells and the formation of the neuroepithelium. Tissue movements produce the neural tube which is then exposed to signals that provide patterning information to neural progenitors. The intracellular response to these signals, via a gene regulatory network, governs the spatial and temporal differentiation of progenitors into specific cell types, facilitating the assembly of functional neuronal circuits. The interplay between the gene regulatory network, cell movement, and tissue mechanics generates the conserved neural tube pattern observed across species. In this review we offer an overview of the molecular and cellular processes governing the formation and patterning of the neural tube, highlighting how the remarkable complexity and precision of vertebrate nervous system arises. We argue that a multidisciplinary and multiscale understanding of the neural tube development, paired with the study of species-specific strategies, will be crucial to tackle the open questions.
Collapse
Affiliation(s)
| | - James Briscoe
- The Francis Crick Institute, London, United Kingdom.
| | | |
Collapse
|
2
|
Bolinger AA, Frazier A, La JH, Allen JA, Zhou J. Orphan G Protein-Coupled Receptor GPR37 as an Emerging Therapeutic Target. ACS Chem Neurosci 2023; 14:3318-3334. [PMID: 37676000 PMCID: PMC11144446 DOI: 10.1021/acschemneuro.3c00479] [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] [Indexed: 09/08/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are successful druggable targets, making up around 35% of all FDA-approved medications. However, a large number of receptors remain orphaned, with no known endogenous ligand, representing a challenging but untapped area to discover new therapeutic targets. Among orphan GPCRs (oGPCRs) of interest, G protein-coupled receptor 37 (GPR37) is highly expressed in the central nervous system (CNS), particularly in the spinal cord and oligodendrocytes. While its cellular signaling mechanisms and endogenous receptor ligands remain elusive, GPR37 has been implicated in several important neurological conditions, including Parkinson's disease (PD), inflammation, pain, autism, and brain tumors. GPR37 structure, signaling, emerging physiology, and pharmacology are reviewed while integrating a discussion on potential therapeutic indications and opportunities.
Collapse
Affiliation(s)
- Andrew A. Bolinger
- Department of Pharmacology and Toxicology, Center for Addiction Sciences and Therapeutics, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Andrew Frazier
- Department of Pharmacology and Toxicology, Center for Addiction Sciences and Therapeutics, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Jun-Ho La
- Department of Neurobiology, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - John A. Allen
- Department of Pharmacology and Toxicology, Center for Addiction Sciences and Therapeutics, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Jia Zhou
- Department of Pharmacology and Toxicology, Center for Addiction Sciences and Therapeutics, University of Texas Medical Branch, Galveston, Texas 77555, United States
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
Garcia-Martin G, Alcover-Sanchez B, Wandosell F, Cubelos B. Pathways Involved in Remyelination after Cerebral Ischemia. Curr Neuropharmacol 2022; 20:751-765. [PMID: 34151767 PMCID: PMC9878953 DOI: 10.2174/1570159x19666210610093658] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 05/05/2021] [Accepted: 05/12/2021] [Indexed: 11/22/2022] Open
Abstract
Brain ischemia, also known as ischemic stroke, occurs when there is a lack of blood supply into the brain. When an ischemic insult appears, both neurons and glial cells can react in several ways that will determine the severity and prognosis. This high heterogeneity of responses has been a major obstacle in developing effective treatments or preventive methods for stroke. Although white matter pathophysiology has not been deeply assessed in stroke, its remodelling can greatly influence the clinical outcome and the disability degree. Oligodendrocytes, the unique cell type implied in CNS myelination, are sensible to ischemic damage. Loss of myelin sheaths can compromise axon survival, so new Oligodendrocyte Precursor Cells are required to restore brain function. Stroke can, therefore, enhance oligodendrogenesis to regenerate those new oligodendrocytes that will ensheath the damaged axons. Given that myelination is a highly complex process that requires coordination of multiple pathways such as Sonic Hedgehog, RTKs or Wnt/β-catenin, we will analyse new research highlighting their importance after brain ischemia. In addition, oligodendrocytes are not isolated cells inside the brain, but rather form part of a dynamic environment of interactions between neurons and glial cells. For this reason, we will put some context into how microglia and astrocytes react against stroke and influence oligodendrogenesis to highlight the relevance of remyelination in the ischemic brain. This will help to guide future studies to develop treatments focused on potentiating the ability of the brain to repair the damage.
Collapse
Affiliation(s)
- Gonzalo Garcia-Martin
- Departamento de Biología Molecular and Centro Biología Molecular “Severo Ochoa”, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
| | - Berta Alcover-Sanchez
- Departamento de Biología Molecular and Centro Biología Molecular “Severo Ochoa”, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
| | - Francisco Wandosell
- Departamento de Biología Molecular and Centro Biología Molecular “Severo Ochoa”, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
| | - Beatriz Cubelos
- Departamento de Biología Molecular and Centro Biología Molecular “Severo Ochoa”, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain,Address correspondence to this author at the Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Nicolás Cabrera 1, Universidad Autónoma de Madrid, 28049 Madrid, Spain; Tel: 34-91-1964561; Fax: 34-91-1964420; E-mail:
| |
Collapse
|
5
|
Starikov L, Kottmann AH. Diminished Ventral Oligodendrocyte Precursor Generation Results in the Subsequent Over-production of Dorsal Oligodendrocyte Precursors of Aberrant Morphology and Function. Neuroscience 2020; 450:15-28. [PMID: 32450295 DOI: 10.1016/j.neuroscience.2020.05.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 05/12/2020] [Accepted: 05/13/2020] [Indexed: 12/28/2022]
Abstract
Oligodendrocyte precursor cells (OPCs) arise sequentially first from a ventral and then from a dorsal precursor domain at the end of neurogenesis during spinal cord development. Whether the sequential production of OPCs is of physiological significance has not been examined. Here we show that ablating Shh signaling from nascent ventricular zone derivatives and partially from the floor plate results in a severe diminishment of ventral derived OPCs but normal numbers of motor neurons in the postnatal spinal cord. In the absence of ventral vOPCs, dorsal dOPCs populate the entire spinal cord resulting in an increased OPC density in the ventral horns. These OPCs take on an altered morphology, do not participate in the removal of excitatory vGlut1 synapses from injured motor neurons, and exhibit morphological features similar to those found in the vicinity of motor neurons in the SOD1 mouse model of Amyotrophic Lateral Sclerosis (ALS). Our data indicate that vOPCs prevent dOPCs from invading ventral spinal cord laminae and suggest that vOPCs have a unique ability to communicate with injured motor neurons.
Collapse
Affiliation(s)
- Lev Starikov
- City University of New York School of Medicine (CSOM) at City College of New York, Dept. of Molecular, Cellular and Biomedical Sciences, New York City, NY 10031, USA; City University of New York Graduate Center, Molecular, Cellular and Developmental Subprogram, New York City, NY 10016, USA
| | - Andreas H Kottmann
- City University of New York School of Medicine (CSOM) at City College of New York, Dept. of Molecular, Cellular and Biomedical Sciences, New York City, NY 10031, USA; City University of New York Graduate Center, Molecular, Cellular and Developmental Subprogram, New York City, NY 10016, USA.
| |
Collapse
|
6
|
Laouarem Y, Traiffort E. Developmental and Repairing Production of Myelin: The Role of Hedgehog Signaling. Front Cell Neurosci 2018; 12:305. [PMID: 30237763 PMCID: PMC6135882 DOI: 10.3389/fncel.2018.00305] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 08/22/2018] [Indexed: 11/13/2022] Open
Abstract
Since the discovery of its role as a morphogen directing ventral patterning of the spinal cord, the secreted protein Sonic Hedgehog (Shh) has been implicated in a wide array of events contributing to the development, maintenance and repair of the central nervous system (CNS). One of these events is the generation of oligodendrocytes, the glial cells of the CNS responsible for axon myelination. In embryo, the first oligodendroglial cells arise from the ventral ventricular zone in the developing brain and spinal cord where Shh induces the basic helix-loop-helix transcription factors Olig1 and Olig2 both necessary and sufficient for oligodendrocyte production. Later on, Shh signaling participates in the production of oligodendroglial cells in the dorsal ventricular-subventricular zone in the postnatal forebrain. Finally, the modulation of Hedgehog signaling activity promotes the repair of demyelinated lesions. This mini-review article focuses on the Shh-dependent molecular mechanisms involved in the spatial and temporal control of oligodendrocyte lineage appearance. The apparent intricacy of the roles of two essential components of Shh signaling, Smoothened and Gli1, in the postnatal production of myelin and its regeneration following a demyelinating event is also highlighted. A deeper understanding of the implication of each of the components that regulate oligodendrogenesis and myelination should beneficially influence the therapeutic strategies in the field of myelin diseases.
Collapse
Affiliation(s)
| | - Elisabeth Traiffort
- Small Molecules of Neuroprotection, Neuroregeneration and Remyelination – U1195, INSERM, University Paris-Sud/Paris-Saclay, Kremlin-Bicêtre, France
| |
Collapse
|
7
|
Farreny MA, Agius E, Bel-Vialar S, Escalas N, Khouri-Farah N, Soukkarieh C, Danesin C, Pituello F, Cochard P, Soula C. FGF signaling controls Shh-dependent oligodendroglial fate specification in the ventral spinal cord. Neural Dev 2018. [PMID: 29519242 PMCID: PMC5842613 DOI: 10.1186/s13064-018-0100-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Background Most oligodendrocytes of the spinal cord originate from ventral progenitor cells of the pMN domain, characterized by expression of the transcription factor Olig2. A minority of oligodendrocytes is also recognized to emerge from dorsal progenitors during fetal development. The prevailing view is that generation of ventral oligodendrocytes depends on Sonic hedgehog (Shh) while dorsal oligodendrocytes develop under the influence of Fibroblast Growth Factors (FGFs). Results Using the well-established model of the chicken embryo, we show that ventral spinal progenitor cells activate FGF signaling at the onset of oligodendrocyte precursor cell (OPC) generation. Inhibition of FGF receptors at that time appears sufficient to prevent generation of ventral OPCs, highlighting that, in addition to Shh, FGF signaling is required also for generation of ventral OPCs. We further reveal an unsuspected interplay between Shh and FGF signaling by showing that FGFs serve dual essential functions in ventral OPC specification. FGFs are responsible for timely induction of a secondary Shh signaling center, the lateral floor plate, a crucial step to create the burst of Shh required for OPC specification. At the same time, FGFs prevent down-regulation of Olig2 in pMN progenitor cells as these cells receive higher threshold of the Shh signal. Finally, we bring arguments favoring a key role of newly differentiated neurons acting as providers of the FGF signal required to trigger OPC generation in the ventral spinal cord. Conclusion Altogether our data reveal that the FGF signaling pathway is activated and required for OPC commitment in the ventral spinal cord. More generally, our data may prove important in defining strategies to produce large populations of determined oligodendrocyte precursor cells from undetermined neural progenitors, including stem cells. In the long run, these new data could be useful in attempts to stimulate the oligodendrocyte fate in residing neural stem cells.
Collapse
Affiliation(s)
- Marie-Amélie Farreny
- Centre de Biologie du Développement (CBD) CNRS/UPS, Centre de Biologie Intégrative (CBI), Université de Toulouse, F-31062, Toulouse, France
| | - Eric Agius
- Centre de Biologie du Développement (CBD) CNRS/UPS, Centre de Biologie Intégrative (CBI), Université de Toulouse, F-31062, Toulouse, France
| | - Sophie Bel-Vialar
- Centre de Biologie du Développement (CBD) CNRS/UPS, Centre de Biologie Intégrative (CBI), Université de Toulouse, F-31062, Toulouse, France
| | - Nathalie Escalas
- Centre de Biologie du Développement (CBD) CNRS/UPS, Centre de Biologie Intégrative (CBI), Université de Toulouse, F-31062, Toulouse, France
| | - Nagham Khouri-Farah
- Centre de Biologie du Développement (CBD) CNRS/UPS, Centre de Biologie Intégrative (CBI), Université de Toulouse, F-31062, Toulouse, France
| | - Chadi Soukkarieh
- Centre de Biologie du Développement (CBD) CNRS/UPS, Centre de Biologie Intégrative (CBI), Université de Toulouse, F-31062, Toulouse, France
| | - Cathy Danesin
- Centre de Biologie du Développement (CBD) CNRS/UPS, Centre de Biologie Intégrative (CBI), Université de Toulouse, F-31062, Toulouse, France
| | - Fabienne Pituello
- Centre de Biologie du Développement (CBD) CNRS/UPS, Centre de Biologie Intégrative (CBI), Université de Toulouse, F-31062, Toulouse, France
| | - Philippe Cochard
- Centre de Biologie du Développement (CBD) CNRS/UPS, Centre de Biologie Intégrative (CBI), Université de Toulouse, F-31062, Toulouse, France
| | - Cathy Soula
- Centre de Biologie du Développement (CBD) CNRS/UPS, Centre de Biologie Intégrative (CBI), Université de Toulouse, F-31062, Toulouse, France.
| |
Collapse
|
8
|
Hashimoto H, Jiang W, Yoshimura T, Moon KH, Bok J, Ikenaka K. Strong sonic hedgehog signaling in the mouse ventral spinal cord is not required for oligodendrocyte precursor cell (OPC) generation but is necessary for correct timing of its generation. Neurochem Int 2017; 119:178-183. [PMID: 29122585 DOI: 10.1016/j.neuint.2017.11.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 10/31/2017] [Accepted: 11/01/2017] [Indexed: 12/15/2022]
Abstract
In the mouse neural tube, sonic hedgehog (Shh) secreted from the floor plate (FP) and the notochord (NC) regulates ventral patterning of the neural tube, and later is essential for the generation of oligodendrocyte precursor cells (OPCs). During early development, the NC is adjacent to the neural tube and induces ventral domains in it, including the FP. In the later stage of development, during gliogenesis in the spinal cord, the pMN domain receives strong Shh signaling input. While this is considered to be essential for the generation of OPCs, the actual role of this strong input in OPC generation remains unclear. Here we studied OPC generation in bromi mutant mice which show abnormal ciliary structure. Shh signaling occurs within cilia and has been reported to be weak in bromi mutants. At E11.5, accumulation of Patched1 mRNA, a Shh signaling reporter, is observed in the pMN domain of wild type but not bromi mutants, whereas expression of Gli1 mRNA, another Shh reporter, disappeared. Thus, Shh signaling input to the pMN domain at E12.5 was reduced in bromi mutant mice. In these mutants, induction of the FP structure was delayed and its size was reduced compared to wild type mice. Furthermore, while the p3 and pMN domains were induced, the length of the Nkx2.2-positive region and the number of Olig2-positive cells decreased. The number of OPCs was also significantly decreased in the E12.5 and E14.5 bromi mutant spinal cord. In contrast, motor neuron (MN) production, detected by HB9 expression, significantly increased. It is likely that the transition from MN production to OPC generation in the pMN domain is impaired in bromi mutant mice. These results suggest that strong Shh input to the pMN domain is not required for OPC generation but is essential for producing a sufficient number of OPCs.
Collapse
Affiliation(s)
- Hirokazu Hashimoto
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Aichi 444-8787, Japan; Department of Physiological Sciences, School of Life Sciences, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan
| | - Wen Jiang
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Aichi 444-8787, Japan; Department of Physiological Sciences, School of Life Sciences, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan
| | - Takeshi Yoshimura
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Aichi 444-8787, Japan; Department of Physiological Sciences, School of Life Sciences, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan
| | - Kyeong-Hye Moon
- Department of Anatomy, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea; BK21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Jinwoong Bok
- Department of Anatomy, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea; Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea; BK21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Kazuhiro Ikenaka
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Aichi 444-8787, Japan; Department of Physiological Sciences, School of Life Sciences, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan.
| |
Collapse
|
9
|
Ono K, Hirahara Y, Gotoh H, Nomura T, Takebayashi H, Yamada H, Ikenaka K. Origin of Oligodendrocytes in the Vertebrate Optic Nerve: A Review. Neurochem Res 2017; 43:3-11. [PMID: 28980095 DOI: 10.1007/s11064-017-2404-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 09/12/2017] [Accepted: 09/19/2017] [Indexed: 01/25/2023]
Abstract
One of the unsolved problems in the research field of oligodendrocyte (OL) development has been the site(s) of origin of optic nerve OLs and its precursor cells (OPCs). It is generally accepted that OLs in the optic nerve are derived from the brain, and thus optic nerve OLs are immigrant cells. We previously demonstrated the brain origin of optic nerve OPCs in chick embryos. However, the site of optic nerve OPC origin has not been examined experimentally in developing rodents for the past two decades. We have recently reported that optic nerve OPCs in mice arise in the preoptic area by E12.5 and gradually migrate caudally and enter the optic nerve. These OPCs give rise to myelinating OLs in the optic nerve in the postnatal or adult stages. Surprisingly, there are species differences with respect to the origin of optic nerve OPCs between chicks and mice. Here, we summarize the site of OPC origin in the optic nerve based on our own previous and recent results, and discuss possible mechanisms underlying these species differences.
Collapse
Affiliation(s)
- Katsuhiko Ono
- Developmental Neurobiology, Kyoto Prefectural University of Medicine, Kyoto, 606-0823, Japan.
| | - Yukie Hirahara
- Department of Anatomy and Cell Science, Kansai Medical University, Osaka, Japan
| | - Hitoshi Gotoh
- Developmental Neurobiology, Kyoto Prefectural University of Medicine, Kyoto, 606-0823, Japan
| | - Tadashi Nomura
- Developmental Neurobiology, Kyoto Prefectural University of Medicine, Kyoto, 606-0823, Japan
| | | | - Hisao Yamada
- Department of Anatomy and Cell Science, Kansai Medical University, Osaka, Japan
| | - Kazuhiro Ikenaka
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences (NIPS), Okazaki, Japan.,Department of Physiological Sciences, School of Life Science, The Graduate University of Advanced Studies (Sokendai), Miki-cho, Kanagawa, Japan
| |
Collapse
|
10
|
Wang LC, Almazan G. Role of Sonic Hedgehog Signaling in Oligodendrocyte Differentiation. Neurochem Res 2016; 41:3289-3299. [PMID: 27639396 DOI: 10.1007/s11064-016-2061-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 08/26/2016] [Accepted: 09/08/2016] [Indexed: 11/28/2022]
Abstract
During development, the secreted molecule Sonic Hedgehog (Shh) is required for lineage specification and proliferation of oligodendrocyte progenitors (OLPs), which are the glia cells responsible for the myelination of axons in the central nervous system (CNS). Shh signaling has been implicated in controlling both the generation of oligodendrocytes (OLGs) during embryonic development and their production in adulthood. Although, some evidence points to a role of Shh signaling in OLG development, its involvement in OLG differentiation remains to be fully determined. The objective of this study was to assess whether Shh signaling is involved in OLG differentiation after neural stem cell commitment to the OLG lineage. To address these questions, we manipulated Shh signaling using cyclopamine, a potent inhibitor of Shh signaling activator Smoothened (Smo), alone or combined with the agonist SAG in OLG primary cultures and assessed expression of myelin-specific markers. We found that inactivation of Shh signaling caused a dose-dependent decrease in myelin basic protein (MBP) and myelin associated glycoprotein (MAG) in differentiating OLGs. Co-treatment of the cells with SAG reversed the inhibitory effect of cyclopamine on both myelin-specific protein levels and morphological changes associated with it. Further experiments are required to elucidate the molecular mechanism by which Shh signaling regulates OLG differentiation.
Collapse
Affiliation(s)
- Li-Chun Wang
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada
| | - Guillermina Almazan
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada.
| |
Collapse
|
11
|
Traiffort E, Zakaria M, Laouarem Y, Ferent J. Hedgehog: A Key Signaling in the Development of the Oligodendrocyte Lineage. J Dev Biol 2016; 4:jdb4030028. [PMID: 29615592 PMCID: PMC5831774 DOI: 10.3390/jdb4030028] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 08/26/2016] [Accepted: 08/31/2016] [Indexed: 01/11/2023] Open
Abstract
The Hedgehog morphogen aroused an enormous interest since it was characterized as an essential signal for ventral patterning of the spinal cord two decades ago. The pathway is notably implicated in the initial appearance of the progenitors of oligodendrocytes (OPCs), the glial cells of the central nervous system which after maturation are responsible for axon myelination. In accordance with the requirement for Hedgehog signaling in ventral patterning, the earliest identifiable cells in the oligodendrocyte lineage are derived from the ventral ventricular zone of the developing spinal cord and brain. Here, we present the current knowledge about the involvement of Hedgehog signaling in the strict spatial and temporal regulation which characterizes the initiation and progression of the oligodendrocyte lineage. We notably describe the ability of the Hedgehog signaling to tightly orchestrate the appearance of specific combinations of genes in concert with other pathways. We document the molecular mechanisms controlling Hedgehog temporal activity during OPC specification. The contribution of the pathway to aspects of OPC development different from their specification is also highlighted especially in the optic nerve. Finally, we report the data demonstrating that Hedgehog signaling-dependency is not a universal situation for oligodendrocyte generation as evidenced in the dorsal spinal cord in contrast to the dorsal forebrain.
Collapse
Affiliation(s)
- Elisabeth Traiffort
- Neuroprotective, Neuroregenerative and Remyelinating Small Molecules' U1195, INSERM-Université Paris-Sud, Université Paris-Saclay, 80 rue du Général Leclerc, Kremlin-Bicêtre F-94276, France.
| | - Mary Zakaria
- Neuroprotective, Neuroregenerative and Remyelinating Small Molecules' U1195, INSERM-Université Paris-Sud, Université Paris-Saclay, 80 rue du Général Leclerc, Kremlin-Bicêtre F-94276, France.
| | - Yousra Laouarem
- Neuroprotective, Neuroregenerative and Remyelinating Small Molecules' U1195, INSERM-Université Paris-Sud, Université Paris-Saclay, 80 rue du Général Leclerc, Kremlin-Bicêtre F-94276, France.
| | - Julien Ferent
- IRCM, Molecular Biology of Neural Development, 110 Pine Avenue West, Montreal, QC H2W 1R7, Canada.
| |
Collapse
|
12
|
Lopez Juarez A, He D, Richard Lu Q. Oligodendrocyte progenitor programming and reprogramming: Toward myelin regeneration. Brain Res 2016; 1638:209-220. [PMID: 26546966 PMCID: PMC5119932 DOI: 10.1016/j.brainres.2015.10.051] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Revised: 10/05/2015] [Accepted: 10/27/2015] [Indexed: 01/26/2023]
Abstract
Demyelinating diseases such as multiple sclerosis (MS) are among the most disabling and cost-intensive neurological disorders. The loss of myelin in the central nervous system, produced by oligodendrocytes (OLs), impairs saltatory nerve conduction, leading to motor and cognitive deficits. Immunosuppression therapy has a limited efficacy in MS patients, arguing for a paradigm shift to strategies that target OL lineage cells to achieve myelin repair. The inhibitory microenvironment in MS lesions abrogates the expansion and differentiation of resident OL precursor cells (OPCs) into mature myelin-forming OLs. Recent studies indicate that OPCs display a highly plastic ability to differentiate into alternative cell lineages under certain circumstances. Thus, understanding the mechanisms that maintain and control OPC fate and differentiation into mature OLs in a hostile, non-permissive lesion environment may open new opportunities for regenerative therapies. In this review, we will focus on 1) the plasticity of OPCs in terms of their developmental origins, distribution, and differentiation potentials in the normal and injured brain; 2) recent discoveries of extrinsic and intrinsic factors and small molecule compounds that control OPC specification and differentiation; and 3) therapeutic potential for motivation of neural progenitor cells and reprogramming of differentiated cells into OPCs and their likely impacts on remyelination. OL-based therapies through activating regenerative potentials of OPCs or cell replacement offer exciting opportunities for innovative strategies to promote remyelination and neuroprotection in devastating demyelinating diseases like MS. This article is part of a Special Issue entitled SI:NG2-glia(Invited only).
Collapse
Affiliation(s)
- Alejandro Lopez Juarez
- Department of Pediatrics, Divisions of Experimental Hematology and Cancer Biology & Developmental Biology, Cincinnati Children׳s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Danyang He
- Department of Pediatrics, Divisions of Experimental Hematology and Cancer Biology & Developmental Biology, Cincinnati Children׳s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Q Richard Lu
- Department of Pediatrics, Divisions of Experimental Hematology and Cancer Biology & Developmental Biology, Cincinnati Children׳s Hospital Medical Center, Cincinnati, OH 45229, USA.
| |
Collapse
|
13
|
Low Density Lipoprotein Receptor Related Proteins as Regulators of Neural Stem and Progenitor Cell Function. Stem Cells Int 2016; 2016:2108495. [PMID: 26949399 PMCID: PMC4754494 DOI: 10.1155/2016/2108495] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 11/24/2015] [Accepted: 01/06/2016] [Indexed: 12/20/2022] Open
Abstract
The central nervous system (CNS) is a highly organised structure. Many signalling systems work in concert to ensure that neural stem cells are appropriately directed to generate progenitor cells, which in turn mature into functional cell types including projection neurons, interneurons, astrocytes, and oligodendrocytes. Herein we explore the role of the low density lipoprotein (LDL) receptor family, in particular family members LRP1 and LRP2, in regulating the behaviour of neural stem and progenitor cells during development and adulthood. The ability of LRP1 and LRP2 to bind a diverse and extensive range of ligands, regulate ligand endocytosis, recruit nonreceptor tyrosine kinases for direct signal transduction and signal in conjunction with other receptors, enables them to modulate many crucial neural cell functions.
Collapse
|
14
|
De Luca A, Cerrato V, Fucà E, Parmigiani E, Buffo A, Leto K. Sonic hedgehog patterning during cerebellar development. Cell Mol Life Sci 2016; 73:291-303. [PMID: 26499980 PMCID: PMC11108499 DOI: 10.1007/s00018-015-2065-1] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 10/06/2015] [Accepted: 10/08/2015] [Indexed: 01/30/2023]
Abstract
The morphogenic factor sonic hedgehog (Shh) actively orchestrates many aspects of cerebellar development and maturation. During embryogenesis, Shh signaling is active in the ventricular germinal zone (VZ) and represents an essential signal for proliferation of VZ-derived progenitors. Later, Shh secreted by Purkinje cells sustains the amplification of postnatal neurogenic niches: the external granular layer and the prospective white matter, where excitatory granule cells and inhibitory interneurons are produced, respectively. Moreover, Shh signaling affects Bergmann glial differentiation and promotes cerebellar foliation during development. Here we review the most relevant functions of Shh during cerebellar ontogenesis, underlying its role in physiological and pathological conditions.
Collapse
Affiliation(s)
- Annarita De Luca
- Department of Neuroscience Rita Levi-Montalcini, University of Turin, 10126, Turin, Italy
- Neuroscience Institute Cavalieri Ottolenghi, Regione Gonzole 10, 10043, Orbassano, Turin, Italy
| | - Valentina Cerrato
- Department of Neuroscience Rita Levi-Montalcini, University of Turin, 10126, Turin, Italy
- Neuroscience Institute Cavalieri Ottolenghi, Regione Gonzole 10, 10043, Orbassano, Turin, Italy
| | - Elisa Fucà
- Department of Neuroscience Rita Levi-Montalcini, University of Turin, 10126, Turin, Italy
- Neuroscience Institute Cavalieri Ottolenghi, Regione Gonzole 10, 10043, Orbassano, Turin, Italy
| | - Elena Parmigiani
- Department of Neuroscience Rita Levi-Montalcini, University of Turin, 10126, Turin, Italy
- Neuroscience Institute Cavalieri Ottolenghi, Regione Gonzole 10, 10043, Orbassano, Turin, Italy
| | - Annalisa Buffo
- Department of Neuroscience Rita Levi-Montalcini, University of Turin, 10126, Turin, Italy
- Neuroscience Institute Cavalieri Ottolenghi, Regione Gonzole 10, 10043, Orbassano, Turin, Italy
| | - Ketty Leto
- Department of Neuroscience Rita Levi-Montalcini, University of Turin, 10126, Turin, Italy.
- Neuroscience Institute Cavalieri Ottolenghi, Regione Gonzole 10, 10043, Orbassano, Turin, Italy.
| |
Collapse
|
15
|
Abstract
Oligodendrocyte precursor cells (OPCs) originate in the ventricular zones (VZs) of the brain and spinal cord and migrate throughout the developing central nervous system (CNS) before differentiating into myelinating oligodendrocytes (OLs). It is not known whether OPCs or OLs from different parts of the VZ are functionally distinct. OPCs persist in the postnatal CNS, where they continue to divide and generate myelinating OLs at a decreasing rate throughout adult life in rodents. Adult OPCs respond to injury or disease by accelerating their cell cycle and increasing production of OLs to replace lost myelin. They also form synapses with unmyelinated axons and respond to electrical activity in those axons by generating more OLs and myelin locally. This experience-dependent "adaptive" myelination is important in some forms of plasticity and learning, for example, motor learning. We review the control of OL lineage development, including OL population dynamics and adaptive myelination in the adult CNS.
Collapse
Affiliation(s)
- Dwight E Bergles
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, WBSB 1001, Baltimore, Maryland 21205
| | - William D Richardson
- Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, United Kingdom
| |
Collapse
|
16
|
Cohen M, Kicheva A, Ribeiro A, Blassberg R, Page KM, Barnes CP, Briscoe J. Ptch1 and Gli regulate Shh signalling dynamics via multiple mechanisms. Nat Commun 2015; 6:6709. [PMID: 25833741 PMCID: PMC4396374 DOI: 10.1038/ncomms7709] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 02/20/2015] [Indexed: 12/20/2022] Open
Abstract
In the vertebrate neural tube, the morphogen Sonic Hedgehog (Shh) establishes a characteristic pattern of gene expression. Here we quantify the Shh gradient in the developing mouse neural tube and show that while the amplitude of the gradient increases over time, the activity of the pathway transcriptional effectors, Gli proteins, initially increases but later decreases. Computational analysis of the pathway suggests three mechanisms that could contribute to this adaptation: transcriptional upregulation of the inhibitory receptor Ptch1, transcriptional downregulation of Gli and the differential stability of active and inactive Gli isoforms. Consistent with this, Gli2 protein expression is downregulated during neural tube patterning and adaptation continues when the pathway is stimulated downstream of Ptch1. Moreover, the Shh-induced upregulation of Gli2 transcription prevents Gli activity levels from adapting in a different cell type, NIH3T3 fibroblasts, despite the upregulation of Ptch1. Multiple mechanisms therefore contribute to the intracellular dynamics of Shh signalling, resulting in different signalling dynamics in different cell types.
Collapse
Affiliation(s)
- Michael Cohen
- MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Anna Kicheva
- MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Ana Ribeiro
- MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Robert Blassberg
- MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Karen M Page
- Department of Mathematics and CoMPLEX, University College London, Gower Street, London WC1E 6BT, UK
| | - Chris P Barnes
- 1] Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK [2] Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - James Briscoe
- MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| |
Collapse
|
17
|
Huang N, Niu J, Feng Y, Xiao L. Oligodendroglial Development: New Roles for Chromatin Accessibility. Neuroscientist 2015; 21:579-88. [PMID: 25564030 DOI: 10.1177/1073858414565467] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In the central nervous system, the generation of mature oligodendrocytes from their progenitors is a critical step in myelination, which is essential for normal nervous system function. Thus, understanding the regulatory mechanism underlying oligodendroglial development is of great importance, especially for the development of new therapeutic strategies that promote remyelination in demyelinating diseases, such as multiple sclerosis. Previous studies have focused on genetic patterns and revealed a network of cell signaling pathways and related transcription factors involved in oligodendroglial lineage development. Recently, epigenetic regulation, which refers to regulation of gene expression by adjusting the environment of the genes has been shown to play a profound role during oligodendroglial development. In this review, we summarize the recent data demonstrating the effects of chromatin modification and remodeling in regulating oligodendroglial development and discuss the use of high-throughput analysis and bio-informatics in future studies.
Collapse
Affiliation(s)
- Nanxin Huang
- Department of Histology and Embryology, Faculty of Basic Medicine, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing, China
| | - Jianqin Niu
- Department of Histology and Embryology, Faculty of Basic Medicine, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing, China
| | - Yue Feng
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | - Lan Xiao
- Department of Histology and Embryology, Faculty of Basic Medicine, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing, China
| |
Collapse
|
18
|
Mitew S, Hay C, Peckham H, Xiao J, Koenning M, Emery B. Mechanisms regulating the development of oligodendrocytes and central nervous system myelin. Neuroscience 2014; 276:29-47. [DOI: 10.1016/j.neuroscience.2013.11.029] [Citation(s) in RCA: 154] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 11/13/2013] [Accepted: 11/14/2013] [Indexed: 12/29/2022]
|
19
|
Transgenic overexpression of Sox17 promotes oligodendrocyte development and attenuates demyelination. J Neurosci 2013; 33:12528-42. [PMID: 23884956 DOI: 10.1523/jneurosci.0536-13.2013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We have previously demonstrated that Sox17 regulates cell cycle exit and differentiation in oligodendrocyte progenitor cells. Here we investigated its function in white matter (WM) development and adult injury with a newly generated transgenic mouse overexpressing Sox17 in the oligodendrocyte lineage under the CNPase promoter. Sox17 overexpression in CNP-Sox17 mice sequentially promoted postnatal oligodendrogenesis, increasing NG2 progenitor cells from postnatal day (P) 15, then O4+ and CC1+ cells at P30 and P120, respectively. Total Olig2+ oligodendrocyte lineage cells first decreased between P8 and P22 through Sox17-mediated increase in apoptotic cell death, and thereafter significantly exceeded WT levels from P30 when cell death had ceased. CNP-Sox17 mice showed increased Gli2 protein levels and Gli2+ cells in WM, indicating that Sox17 promotes the generation of oligodendrocyte lineage cells through Hedgehog signaling. Sox17 overexpression prevented cell loss after lysolecithin-induced demyelination by increasing Olig2+ and CC1+ cells in response to injury. Furthermore, Sox17 overexpression abolished the injury-induced increase in TCF7L2/TCF4+ cells, and protected oligodendrocytes from apoptosis by preventing decreases in Gli2 and Bcl-2 expression that were observed in WT lesions. Our study thus reveals a biphasic effect of Sox17 overexpression on cell survival and oligodendrocyte formation in the developing WM, and that its potentiation of oligodendrocyte survival in the adult confers resistance to injury and myelin loss. This study demonstrates that overexpression of this transcription factor might be a viable protective strategy to mitigate the consequences of demyelination in the adult WM.
Collapse
|
20
|
Indian hedgehog B function is required for the specification of oligodendrocyte progenitor cells in the zebrafish CNS. J Neurosci 2013; 33:1728-33. [PMID: 23345245 DOI: 10.1523/jneurosci.3369-12.2013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A subset of ventral spinal cord precursors, known as pMN precursor cells, initially generate motor neurons and then oligodendrocyte progenitor cells (OPCs), which migrate and differentiate as myelinating oligodendrocytes in the developing neural tube. The switch between motor neuron and oligodendrocyte production by the pMN neural precursors is an important step in building a functional nervous system. However, the precise mechanism that orchestrates the sequential generation of motor neurons and oligodendrocytes within the common population of pMN precursors is still unclear. The current study demonstrates that Indian Hedgehog b (Ihhb), previously known as Echidna Hedgehog, begins to be expressed in the floor plate cells of the ventral spinal cord at the time of OPC specification in zebrafish embryos. Ihhb loss-of-function analysis revealed that Ihhb function is required for OPC specification from pMN precursors by negatively regulating the proliferation of neural precursors. Finally, results showed that Sonic Hedgehog (Shh) could not replace Ihhb function in OPC specification, suggesting that Ihhb and Shh play separate roles in OPC specification. Altogether, data from the present study suggested a novel mechanism, mediated by Ihhb, for the sequential generation of motor neurons and oligodendrocytes from pMN precursors in the ventral spinal cord of zebrafish embryos.
Collapse
|
21
|
He L, Lu QR. Coordinated control of oligodendrocyte development by extrinsic and intrinsic signaling cues. Neurosci Bull 2013; 29:129-43. [PMID: 23494530 DOI: 10.1007/s12264-013-1318-y] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 02/17/2013] [Indexed: 01/06/2023] Open
Abstract
Oligodendrocytes, the myelin-forming cells for axon ensheathment in the central nervous system, are critical for maximizing and maintaining the conduction velocity of nerve impulses and proper brain function. Demyelination caused by injury or disease together with failure of myelin regeneration disrupts the rapid propagation of action potentials along nerve fibers, and is associated with acquired and inherited disorders, including devastating multiple sclerosis and leukodystrophies. The molecular mechanisms of oligodendrocyte myelination and remyelination remain poorly understood. Recently, a series of signaling pathways including Shh, Notch, BMP and Wnt signaling and their intracellular effectors such as Olig1/2, Hes1/5, Smads and TCFs, have been shown to play important roles in regulating oligodendrocyte development and myelination. In this review, we summarize our recent understanding of how these signaling pathways modulate the progression of oligodendrocyte specification and differentiation in a spatiotemporally-specific manner. A better understanding of the complex but coordinated function of extracellular signals and intracellular determinants during oligodendrocyte development will help to devise effective strategies to promote myelin repair for patients with demyelinating diseases.
Collapse
Affiliation(s)
- Li He
- Department of Pediatrics and Obstetrics/Gynaecology, Institute of Stem Cell and Developmental Biology, West China Second Hospital, Sichuan University, Chengdu 610041, China
| | | |
Collapse
|
22
|
Sulfatase 1 promotes the motor neuron-to-oligodendrocyte fate switch by activating Shh signaling in Olig2 progenitors of the embryonic ventral spinal cord. J Neurosci 2013; 32:18018-34. [PMID: 23238718 DOI: 10.1523/jneurosci.3553-12.2012] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In the developing ventral spinal cord, motor neurons (MNs) and oligodendrocyte precursor cells (OPCs) are sequentially generated from a common pool of neural progenitors included in the so-called pMN domain characterized by Olig2 expression. Here, we establish that the secreted Sulfatase 1 (Sulf1) is a major component of the mechanism that causes these progenitors to stop producing MNs and change their fate to generate OPCs. We show that specification of OPCs is severely affected in sulf1-deficient mouse embryos. This defect does not rely on abnormal patterning of the spinal cord or failure in maintenance of pMN progenitors at the onset of OPC specification. Instead, the efficiency of OPC induction is reduced, only few Olig2 progenitors are recruited to generate OPCs, meanwhile they continue to produce MNs beyond the normal timing of the neuroglial switch. Using the chicken embryo, we show that Sulf1 activity is required precisely at the stage of the MN-to-OPC fate switch. Finally, we bring arguments supporting the view that Sulf1 controls the level of Sonic Hedgehog (Shh) signaling activity, behaving as an enhancer rather than an obligatory component in the Shh pathway. Our study provides additional insights into the temporal control of Olig2 progenitor cell fate change by the identification of Sulf1 as an extracellular timing signal in the ventral spinal cord.
Collapse
|
23
|
The (real) neurogenic/gliogenic potential of the postnatal and adult brain parenchyma. ISRN NEUROSCIENCE 2013; 2013:354136. [PMID: 24967310 PMCID: PMC4045543 DOI: 10.1155/2013/354136] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 01/08/2013] [Indexed: 11/17/2022]
Abstract
During the last two decades basic research in neuroscience has remarkably expanded due to the discovery of neural stem cells (NSCs) and adult neurogenesis in the mammalian central nervous system (CNS). The existence of such unexpected plasticity triggered hopes for alternative approaches to brain repair, yet deeper investigation showed that constitutive mammalian neurogenesis is restricted to two small "neurogenic sites" hosting NSCs as remnants of embryonic germinal layers and subserving homeostatic roles in specific neural systems. The fact that in other classes of vertebrates adult neurogenesis is widespread in the CNS and useful for brain repair sometimes creates misunderstandings about the real reparative potential in mammals. Nevertheless, in the mammalian CNS parenchyma, which is commonly considered as "nonneurogenic," some processes of gliogenesis and, to a lesser extent, neurogenesis also occur. This "parenchymal" cell genesis is highly heterogeneous as to the position, identity, and fate of the progenitors. In addition, even the regional outcomes are different. In this paper the heterogeneity of mammalian parenchymal neurogliogenesis will be addressed, also discussing the most common pitfalls and misunderstandings of this growing and promising research field.
Collapse
|
24
|
Bouslama-Oueghlani L, Wehrlé R, Doulazmi M, Chen XR, Jaudon F, Lemaigre-Dubreuil Y, Rivals I, Sotelo C, Dusart I. Purkinje cell maturation participates in the control of oligodendrocyte differentiation: role of sonic hedgehog and vitronectin. PLoS One 2012; 7:e49015. [PMID: 23155445 PMCID: PMC3498367 DOI: 10.1371/journal.pone.0049015] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 10/08/2012] [Indexed: 11/24/2022] Open
Abstract
Oligodendrocyte differentiation is temporally regulated during development by multiple factors. Here, we investigated whether the timing of oligodendrocyte differentiation might be controlled by neuronal differentiation in cerebellar organotypic cultures. In these cultures, the slices taken from newborn mice show very few oligodendrocytes during the first week of culture (immature slices) whereas their number increases importantly during the second week (mature slices). First, we showed that mature cerebellar slices or their conditioned media stimulated oligodendrocyte differentiation in immature slices thus demonstrating the existence of diffusible factors controlling oligodendrocyte differentiation. Using conditioned media from different models of slice culture in which the number of Purkinje cells varies drastically, we showed that the effects of these differentiating factors were proportional to the number of Purkinje cells. To identify these diffusible factors, we first performed a transcriptome analysis with an Affymetrix array for cerebellar cortex and then real-time quantitative PCR on mRNAs extracted from fluorescent flow cytometry sorted (FACS) Purkinje cells of L7-GFP transgenic mice at different ages. These analyses revealed that during postnatal maturation, Purkinje cells down-regulate Sonic Hedgehog and up-regulate vitronectin. Then, we showed that Sonic Hedgehog stimulates the proliferation of oligodendrocyte precursor cells and inhibits their differentiation. In contrast, vitronectin stimulates oligodendrocyte differentiation, whereas its inhibition with blocking antibodies abolishes the conditioned media effects. Altogether, these results suggest that Purkinje cells participate in controlling the timing of oligodendrocyte differentiation in the cerebellum through the developmentally regulated expression of diffusible molecules such as Sonic Hedgehog and vitronectin.
Collapse
Affiliation(s)
- Lamia Bouslama-Oueghlani
- Neurobiologie des Processus Adaptatif, Université Pierre et Marie Curie (UPMC Univ Paris 06), Paris, France
- Neurobiologie des Processus Adaptatif, CNRS (Centre National de Recherche Scientifique), Paris, France
| | - Rosine Wehrlé
- Neurobiologie des Processus Adaptatif, Université Pierre et Marie Curie (UPMC Univ Paris 06), Paris, France
- Neurobiologie des Processus Adaptatif, CNRS (Centre National de Recherche Scientifique), Paris, France
| | - Mohamed Doulazmi
- Neurobiologie des Processus Adaptatif, Université Pierre et Marie Curie (UPMC Univ Paris 06), Paris, France
- Neurobiologie des Processus Adaptatif, CNRS (Centre National de Recherche Scientifique), Paris, France
| | - Xiao Ru Chen
- Neurobiologie des Processus Adaptatif, Université Pierre et Marie Curie (UPMC Univ Paris 06), Paris, France
- Neurobiologie des Processus Adaptatif, CNRS (Centre National de Recherche Scientifique), Paris, France
| | - Fanny Jaudon
- Centre de Recherche de Biochimie Macromoléculaire, Université Montpellier 1 et 2, CNRS UMR 5237, Montpellier, France
| | - Yolande Lemaigre-Dubreuil
- Neurobiologie des Processus Adaptatif, Université Pierre et Marie Curie (UPMC Univ Paris 06), Paris, France
- Neurobiologie des Processus Adaptatif, CNRS (Centre National de Recherche Scientifique), Paris, France
| | - Isabelle Rivals
- Équipe de statistique Appliquée, ESPCI ParisTech (Ecole Supérieure de Physique et Chimie Industrielles de la Ville de Paris), Paris, France
| | - Constantino Sotelo
- Neurobiologie des Processus Adaptatif, Université Pierre et Marie Curie (UPMC Univ Paris 06), Paris, France
- Neurobiologie des Processus Adaptatif, CNRS (Centre National de Recherche Scientifique), Paris, France
- Instituto de Neurociencias, Universidad Miguel Hernández–CSIC, San Juan de Alicante, Spain
| | - Isabelle Dusart
- Neurobiologie des Processus Adaptatif, Université Pierre et Marie Curie (UPMC Univ Paris 06), Paris, France
- Neurobiologie des Processus Adaptatif, CNRS (Centre National de Recherche Scientifique), Paris, France
- * E-mail:
| |
Collapse
|
25
|
Yuelling LW, Waggener CT, Afshari FS, Lister JA, Fuss B. Autotaxin/ENPP2 regulates oligodendrocyte differentiation in vivo in the developing zebrafish hindbrain. Glia 2012; 60:1605-18. [PMID: 22821873 DOI: 10.1002/glia.22381] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 06/05/2012] [Indexed: 01/12/2023]
Abstract
During development, progenitors that are committed to differentiate into oligodendrocytes, the myelinating cells of the central nervous system (CNS), are generated within discrete regions of the neuroepithelium. More specifically, within the developing spinal cord and hindbrain ventrally located progenitor cells that are characterized by the expression of the transcription factor olig2 give temporally rise to first motor neurons and then oligodendrocyte progenitors. The regulation of this temporal neuron-glial switch has been found complex and little is known about the extrinsic factors regulating it. Our studies described here identified a zebrafish ortholog to mammalian atx, which displays evolutionarily conserved expression pattern characteristics. Most interestingly, atx was found to be expressed by cells of the cephalic floor plate during a time period when ventrally-derived oligodendrocyte progenitors arise in the developing hindbrain of the zebrafish. Knock-down of atx expression resulted in a delay and/or inhibition of the timely appearance of oligodendrocyte progenitors and subsequent developmental stages of the oligodendrocyte lineage. This effect of atx knock-down was not accompanied by changes in the number of olig2-positive progenitor cells, the overall morphology of the axonal network or the number of somatic abducens motor neurons. Thus, our studies identified Atx as an extrinsic factor that is likely secreted by cells from the floor plate and that is involved in regulating specifically the progression of olig2-positive progenitor cells into lineage committed oligodendrocyte progenitors.
Collapse
Affiliation(s)
- Larra W Yuelling
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, USA
| | | | | | | | | |
Collapse
|
26
|
Neman J, de Vellis J. A method for deriving homogenous population of oligodendrocytes from mouse embryonic stem cells. Dev Neurobiol 2012; 72:777-88. [DOI: 10.1002/dneu.22008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
27
|
Development and maturation of the spinal cord: implications of molecular and genetic defects. HANDBOOK OF CLINICAL NEUROLOGY 2012; 109:3-30. [PMID: 23098703 DOI: 10.1016/b978-0-444-52137-8.00001-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
The human central nervous system (CNS) may be the most complex structure in the universe. Its development and appropriate specification into phenotypically and spatially distinct neural subpopulations involves a precisely orchestrated response, with thousands of transcriptional regulators combining with epigenetic controls and specific temporal cues in perfect synchrony. Understandably, our insight into the sophisticated molecular mechanisms which underlie spinal cord development are as yet limited. Even less is known about abnormalities of this process - putative genetic and molecular causes of well-described defects have only begun to emerge in recent years. Nonetheless, modern scientific techniques are beginning to demonstrate common patterns and principles amid the tremendous complexity of spinal cord development and maldevelopment. These advances are important, given that developmental anomalies of the spinal cord are an important cause of mortality and morbidity (Sadler, 2000); it is hoped that research advances will lead to better methods to detect, treat, and prevent these lesions.
Collapse
|
28
|
García-López R, Soula C, Martínez S. Expression analysis ofSulf1in the chick forebrain at early and late stages of development. Dev Dyn 2009; 238:2418-29. [DOI: 10.1002/dvdy.22039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
|
29
|
|
30
|
Kessaris N, Pringle N, Richardson WD. Specification of CNS glia from neural stem cells in the embryonic neuroepithelium. Philos Trans R Soc Lond B Biol Sci 2008; 363:71-85. [PMID: 17282992 PMCID: PMC2605487 DOI: 10.1098/rstb.2006.2013] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
All the neurons and glial cells of the central nervous system are generated from the neuroepithelial cells in the walls of the embryonic neural tube, the 'embryonic neural stem cells'. The stem cells seem to be equivalent to the so-called 'radial glial cells', which for many years had been regarded as a specialized type of glial cell. These radial cells generate different classes of neurons in a position-dependent manner. They then switch to producing glial cells (oligodendrocytes and astrocytes). It is not known what drives the neuron-glial switch, although downregulation of pro-neural basic helix-loop-helix transcription factors is one important step. This drives the stem cells from a neurogenic towards a gliogenic mode. The stem cells then choose between developing as oligodendrocytes or astrocytes, of which there might be intrinsically different subclasses. This review focuses on the different extracellular signals and intracellular responses that influence glial generation and the choice between oligodendrocyte and astrocyte fates.
Collapse
|
31
|
Hu JG, Fu SL, Wang YX, Li Y, Jiang XY, Wang XF, Qiu MS, Lu PH, Xu XM. Platelet-derived growth factor-AA mediates oligodendrocyte lineage differentiation through activation of extracellular signal-regulated kinase signaling pathway. Neuroscience 2007; 151:138-47. [PMID: 18093741 DOI: 10.1016/j.neuroscience.2007.10.050] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Revised: 08/31/2007] [Accepted: 11/07/2007] [Indexed: 11/15/2022]
Abstract
Platelet-derived growth factor-AA (PDGF-AA) has been used as a potent mitogen for the proliferation of oligodendrocyte progenitor cells (OPCs). Whether it plays a role in oligodendrocyte lineage differentiation of neural stem cells (NSCs) is unclear. Here we report that PDGF-AA is an instructional signal required for the differentiation of embryonic forebrain NSCs into O4-positive oligodendrocytes. Moreover, such PDGF-AA-induced oligodendrocyte differentiation appears to be mediated by the extracellular signal-regulated kinases 1 and 2 (Erk1/2) but not phosphatidylinositol-3 kinase (PI3K) pathway. Finally, PDGF-AA treatment resulted in a significant increase in the expression of the oligodendrocyte-specific transcriptional factor Olig2 in an Erk1/2-dependent mechanism at early stages of oligodendrogliogenesis. Together, our studies provide cellular and molecular evidence to suggest that PDGF-AA is a key molecule that regulates the differentiation of embryonic NSCs into oligodendrocytes. The action of PDGF-AA is mediated by the activation of Erk pathway which involves the downstream upregulation of transcriptional factor Olig2.
Collapse
Affiliation(s)
- J-G Hu
- Department of Neurobiology, Shanghai Jiaotong University School of Medicine, Shanghai 200025, People's Republic of China
| | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Cheng X, Wang Y, He Q, Qiu M, Whittemore SR, Cao Q. Bone morphogenetic protein signaling and olig1/2 interact to regulate the differentiation and maturation of adult oligodendrocyte precursor cells. Stem Cells 2007; 25:3204-14. [PMID: 17872503 PMCID: PMC2742907 DOI: 10.1634/stemcells.2007-0284] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Promotion of remyelination is an important therapeutic strategy for the treatment of the demyelinating neurological disorders. Adult oligodendrocyte precursor cells (OPCs), which normally reside quiescently in the adult central nervous system (CNS), become activated and proliferative after demyelinating lesions. However, the extent of endogenous remyelination is limited because of the failure of adult OPCs to mature into myelinating oligodendrocytes (OLs) in the demyelinated CNS. Understanding the molecular mechanisms that regulate the differentiation of adult OPCs could lead to new therapeutic strategies to treat these disorders. In this study, we established a stable culture of adult spinal cord OPCs and developed a reliable in vitro protocol to induce their sequential differentiation. Adult OPCs expressed bone morphogenetic protein (BMP) type Ia, Ib, and II receptor subunits, which are required for BMP signal transduction. BMP2 and 4 promoted dose-dependent astrocyte differentiation of adult OPCs with concurrent suppression of OL differentiation. Treatment of OPCs with BMP2 and 4 increased ID4 expression and decreased the expression of olig1 and olig2. Overexpression of olig1 or olig2 blocked the astrocyte differentiation of adult OPCs induced by BMP2 and 4. Furthermore, overexpression of both olig1 and olig2, but not olig1 or olig2 alone, rescued OL differentiation from inhibition by BMP2 and 4. Our results demonstrated that downregulation of olig1 and olig2 is an important mechanism by which BMP2 and 4 inhibit OL differentiation of adult OPCs. These data suggest that blocking BMP signaling combined with olig1/2 overexpression could be a useful therapeutic strategy to enhance endogenous remyelination and facilitate functional recovery in CNS demyelinated disorders. Disclosure of potential conflicts of interest is found at the end of this article.
Collapse
Affiliation(s)
- Xiaoxin Cheng
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Yaping Wang
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Anesthesiology, Second Xian-Ya Hospital of South Central University, Changsha, Hunan, People's Republic of China
| | - Qian He
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Mengsheng Qiu
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Scott R. Whittemore
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Qilin Cao
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA
| |
Collapse
|
33
|
Samanta J, Burke GM, McGuire T, Pisarek AJ, Mukhopadhyay A, Mishina Y, Kessler JA. BMPR1a signaling determines numbers of oligodendrocytes and calbindin-expressing interneurons in the cortex. J Neurosci 2007; 27:7397-407. [PMID: 17626200 PMCID: PMC6672617 DOI: 10.1523/jneurosci.1434-07.2007] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Progenitor cells that express the transcription factor olig1 generate several neural cell types including oligodendrocytes and GABAergic interneurons in the dorsal cortex. The fate of these progenitor cells is regulated by a number of signals including bone morphogenetic proteins (BMPs) secreted in the dorsal forebrain. BMPs signal by binding to heteromeric serine-threonine kinase receptors formed by type I (BMPR1a, BMPR1b, Alk2) and type II (BMPRII) subunits. To determine the specific role of the BMPR1a subunit in lineage commitment by olig1-expressing cells, we used a cre/loxP genetic approach to ablate BMPR1a in these cells while leaving signaling from other subunits intact. There was a reduction in numbers of immature oligodendrocytes in the BMPR1a-null mutant brains at birth. However, by postnatal day 20, the BMPR1a-null mice had a significant increase in the number of mature and immature oligodendrocytes compared with wild-type littermates. There was also an increase in the proportion of calbindin-positive interneurons in the dorsomedial cortex of BMPR1a-null mice at birth without any change in the number of parvalbumin- or calretinin-positive cells. These effects were attributable, at least in part, to a decrease in the length of the cell cycle in subventricular zone progenitor cells. Thus, our findings indicate that BMPR1a mediates the suppressive effects of BMP signaling on oligodendrocyte lineage commitment and on the specification of calbindin-positive interneurons in the dorsomedial cortex.
Collapse
Affiliation(s)
- Jayshree Samanta
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, and
| | - Gordon M. Burke
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, and
| | - Tammy McGuire
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, and
| | - Anna J. Pisarek
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, and
| | - Abhishek Mukhopadhyay
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, and
| | - Yuji Mishina
- Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - John A. Kessler
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, and
| |
Collapse
|
34
|
Fuccillo M, Joyner AL, Fishell G. Morphogen to mitogen: the multiple roles of hedgehog signalling in vertebrate neural development. Nat Rev Neurosci 2006; 7:772-83. [PMID: 16988653 DOI: 10.1038/nrn1990] [Citation(s) in RCA: 339] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Sonic hedgehog has received an enormous amount of attention since its role as a morphogen that directs ventral patterning in the spinal cord was discovered a decade ago. Since that time, a bewildering array of information has been generated concerning both the components of the hedgehog signalling pathway and the remarkable number of contexts in which it functions. Nowhere is this more evident than in the nervous system, where hedgehog signalling has been implicated in events as disparate as axonal guidance and stem cell maintenance. Here we review our present knowledge of the hedgehog signalling pathway and speculate about areas in which further insights into this versatile pathway might be forthcoming.
Collapse
Affiliation(s)
- Marc Fuccillo
- Developmental Genetics Program and the Department of Cell Biology, Skirball Institute of Biomolecular Medicine, New York University Medical Center, 540 First Avenue, New York, NY 10016, USA
| | | | | |
Collapse
|
35
|
Schäfer M, Kinzel D, Winkler C. Discontinuous organization and specification of the lateral floor plate in zebrafish. Dev Biol 2006; 301:117-29. [PMID: 17045256 DOI: 10.1016/j.ydbio.2006.09.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 09/09/2006] [Accepted: 09/11/2006] [Indexed: 01/06/2023]
Abstract
The floor plate is a signaling center in the ventral neural tube of vertebrates with important functions during neural patterning and axon guidance. It is composed of a centrally located medial floor plate (MFP) and a bilaterally positioned lateral floor plate (LFP). While the role of the MFP as source of signaling molecules like, e.g., Sonic Hedgehog (Shh) is well understood, the exact organization and function of the LFP are currently unclear. Based on expression analyses, the one cell wide LFP in zebrafish has been postulated to be a homogenous structure. We instead show that the zebrafish trunk LFP is discontinuously arranged. Single LFP cells alternate with p3 neuronal precursor cells, which develop V3 interneurons along the anteroposterior (AP) axis. Our mutant analyses indicate that both, formation of LFP and p3 cells require Delta-Notch signaling. Importantly, however, the two cell types are differentially regulated by Hedgehog (HH) and Nkx2.2 activities. This implicates a novel mechanism of neural tube patterning, in which distinct cell populations within one domain of the ventral neural tube are differently specified along the AP axis. We conclude that different levels of HH and Nkx2.2 activities are responsible for the alternating appearance of LFP and p3 neuronal progenitor cells in the zebrafish ventral neural tube.
Collapse
Affiliation(s)
- Matthias Schäfer
- Department of Physiological Chemistry I, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | | | | |
Collapse
|
36
|
Danesin C, Agius E, Escalas N, Ai X, Emerson C, Cochard P, Soula C. Ventral neural progenitors switch toward an oligodendroglial fate in response to increased Sonic hedgehog (Shh) activity: involvement of Sulfatase 1 in modulating Shh signaling in the ventral spinal cord. J Neurosci 2006; 26:5037-48. [PMID: 16687495 PMCID: PMC6674256 DOI: 10.1523/jneurosci.0715-06.2006] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In the embryonic chick ventral spinal cord, the initial emergence of oligodendrocytes is a relatively late event that depends on prolonged Sonic hedgehog (Shh) signaling. In this report, we show that specification of oligodendrocyte precursors (OLPs) from ventral Nkx2.2-expressing neural progenitors occurs precisely when these progenitors stop generating neurons, indicating that the mechanism of the neuronal/oligodendroglial switch is a common feature of ventral OLP specification. We further show that an experimental early increase in the concentration of Shh is sufficient to induce premature specification of OLPs at the expense of neuronal genesis indicating that the relative doses of Shh received by ventral progenitors determine whether they become neurons or glia. Accordingly, we observe that the Shh protein accumulates at the apical surface of Nkx2.2-expressing cells just before OLP specification, providing direct evidence that these cells are subjected to a higher concentration of the morphogen when they switch to an oligodendroglial fate. Finally, we show that this abrupt change in Shh distribution is most likely attributable to the timely activity of Sulfatase 1 (Sulf1), a secreted enzym that modulates the sulfation state of heparan sulfate proteoglycans. Sulf1 is expressed in the ventral neuroepithelium just before OLP specification, and we show that its experimental overexpression leads to apical concentration of Shh on neuroepithelial cells, a decisive event for the switch of ventral neural progenitors toward an oligodendroglial fate.
Collapse
|
37
|
Bénazéraf B, Chen Q, Peco E, Lobjois V, Médevielle F, Ducommun B, Pituello F. Identification of an unexpected link between the Shh pathway and a G2/M regulator, the phosphatase CDC25B. Dev Biol 2006; 294:133-47. [PMID: 16564519 DOI: 10.1016/j.ydbio.2006.02.035] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Revised: 01/12/2006] [Accepted: 02/22/2006] [Indexed: 12/23/2022]
Abstract
Sonic hedgehog (Shh) signaling controls numerous aspects of vertebrate development, including proliferation of precursors in different organs. Identification of molecules that link the Shh pathway to cell cycle machinery is therefore of major importance for an understanding of the mechanisms underlying Shh-dependent proliferation. Here, we show that an actor in the control of entry into mitosis, the phosphatase CDC25B, is transcriptionally upregulated by the Shh/Gli pathway. Unlike other G2/M regulators, CDC25B is highly expressed in domains of Shh activity, including the ventral neural tube and the posterior limb bud. Loss- and gain-of-function experiments reveal that Shh contributes to CDC25B transcriptional activation in the neural tube both of chick and mouse embryos. Moreover, CDC25B transcripts are absent from the posterior limb bud of Shh-/- mice, while anterior grafts of Shh-expressing cells in the chicken limb bud induce ectopic CDC25B expression. Arresting the cell cycle does not reduce the level of CDC25B expression in the neural tube strongly suggesting that the upregulation of CDC25B is not an indirect consequence of the Shh-dependent proliferation. These data reveal an unexpected developmental link between the Shh pathway and a participant in G2/M control.
Collapse
Affiliation(s)
- Bertrand Bénazéraf
- Centre de Biologie du Développement, UMR5547 CNRS-Université P. Sabatier, IFR109--Institut d'Exploration Fonctionnelle des Génomes, 118 route de Narbonne, 31062 Toulouse Cedex, France
| | | | | | | | | | | | | |
Collapse
|
38
|
Mukouyama YS, Deneen B, Lukaszewicz A, Novitch BG, Wichterle H, Jessell TM, Anderson DJ. Olig2+ neuroepithelial motoneuron progenitors are not multipotent stem cells in vivo. Proc Natl Acad Sci U S A 2006; 103:1551-6. [PMID: 16432183 PMCID: PMC1345718 DOI: 10.1073/pnas.0510658103] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Neurons and glia are thought to arise from multipotent and self-renewing stem cells, which comprise the majority of neuroepithelial cells in the ventricular zone (VZ) of the early embryonic CNS. However, this idea remains to be tested rigorously, because CNS stem cells have been identified only by using in vitro assays, from which their abundance in vivo cannot be directly inferred. In the hematopoietic system, stem cells are characterized by using prospective isolation and direct in vivo transplantation. Here we have used this approach to ask whether most VZ progenitors behave as stem cells in vivo. The best-studied region of the embryonic CNS for addressing this problem is, arguably, the ventral spinal cord, within which progenitors in the motoneuron progenitor (pMN) domain sequentially generate motoneurons (MNs) and oligodendrocyte precursors (OPs). Virtually all VZ cells in pMN express the transcription factor Olig2. If most of these cells are stem cells, then they should maintain neurogenic potential, even at later, gliogenic stages. To test this hypothesis, we have prospectively isolated Olig2(+) cells from murine embryonic day (E)9.5 and E13.5 spinal cord and directly transplanted them to E2 chick spinal cord. Transplanted E9.5 cells generate both neurons, including MNs and OPs, whereas E13.5 cells generate. The observation that most Olig2(+) progenitors do not maintain neurogenic potential into the period of gliogenesis argues that they do not self-renew. These results do not support the commonly held view that most neuroepithelial cells in the embryonic CNS VZ are stem cells in vivo.
Collapse
Affiliation(s)
- Yoh-suke Mukouyama
- Howard Hughes Medical Institute and Division of Biology 216-76, California Institute of Technology, 1201 East California Boulevard, Pasadena, CA 91125, USA
| | | | | | | | | | | | | |
Collapse
|
39
|
Oh S, Huang X, Chiang C. Specific requirements of sonic hedgehog signaling during oligodendrocyte development. Dev Dyn 2006; 234:489-96. [PMID: 15880651 DOI: 10.1002/dvdy.20422] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Oligodendrocyte precursors (OLPs) in the developing spinal cord are generated from the same part of the ventral neuroepithelium as motor neurons, by inductive processes that include a temporal switch from neuronal to glial cell fate. Recent studies have implicated Shh as a key signal in the generation of both OLPs and ventral neurons. In this study, we used Shh(-/-), Gli3(-/-), and Shh(-/-);Gli3(-/-) mutants to address the role of Shh signaling during oligodendrocyte development. We find that, in the absence of Gli3, Shh signaling is dispensable for the generation and maintenance of OLPs. However, Shh is required for OLPs to emerge at the appropriate developmental stages and for subsequent differentiation of OLPs into mature oligodendrocytes. The initial delay and reduction in OLP generation in Shh(-/-);Gli3(-/-) mutants are accompanied by extended neurogenesis and persistent expression of Neurogenin 2 in the Olig2 progenitor domain, suggesting that Shh signaling influences the timing of neuron-glia fate switching. Thus, our studies suggest that Shh signaling plays multiple roles during development of oligodendrocytes.
Collapse
Affiliation(s)
- Saeock Oh
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| | | | | |
Collapse
|
40
|
Kessaris N, Fogarty M, Iannarelli P, Grist M, Wegner M, Richardson WD. Competing waves of oligodendrocytes in the forebrain and postnatal elimination of an embryonic lineage. Nat Neurosci 2005; 9:173-9. [PMID: 16388308 PMCID: PMC6328015 DOI: 10.1038/nn1620] [Citation(s) in RCA: 802] [Impact Index Per Article: 42.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2005] [Accepted: 11/30/2005] [Indexed: 11/09/2022]
Abstract
The developmental origin of oligodendrocyte progenitors (OLPs) in the forebrain has been controversial. We now show, by Cre-lox fate mapping in transgenic mice, that the first OLPs originate in the medial ganglionic eminence (MGE) and anterior entopeduncular area (AEP) in the ventral forebrain. From there, they populate the entire embryonic telencephalon including the cerebral cortex before being joined by a second wave of OLPs from the lateral and/or caudal ganglionic eminences (LGE and CGE). Finally, a third wave arises within the postnatal cortex. When any one population is destroyed at source by the targeted expression of diphtheria toxin, the remaining cells take over and the mice survive and behave normally, with a normal complement of oligodendrocytes and myelin. Thus, functionally redundant populations of OLPs compete for space in the developing brain. Notably, the embryonic MGE- and AEP-derived population is eliminated during postnatal life, raising questions about the nature and purpose of the competition.
Collapse
Affiliation(s)
- Nicoletta Kessaris
- Wolfson Institute for Biomedical Research and Department of Biology, University College London, Gower Street, London WC1E 6BT, UK.
| | | | | | | | | | | |
Collapse
|
41
|
de Castro F, Bribián A. The molecular orchestra of the migration of oligodendrocyte precursors during development. ACTA ACUST UNITED AC 2005; 49:227-41. [PMID: 16111552 DOI: 10.1016/j.brainresrev.2004.12.034] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2004] [Revised: 11/11/2004] [Accepted: 12/10/2004] [Indexed: 02/06/2023]
Abstract
During development of the central nervous system (CNS), postmitotic cells (including neurons and myelin-generating cells, the oligodendrocytes) migrate from the germinal areas of the neural tube where they originate to their final destination sites. The migration of neurons during development has been extensively studied and has been the topic of detailed reviews. The migration of oligodendrocyte precursor cells (OPCs) is also an extremely complex and precise event, with a widespread migration of OPCs across many regions to colonize the entire CNS. Different mechanisms have been shown to direct the migration of OPCs, among them contact-mediated mechanisms (adhesion molecules) and long-range cues (chemotropic molecules). This review provides a detailed overview and discussion of the cellular and molecular basis of OPCs migration during development. Because it has been shown that neuronal and oligodendroglial lineages share some of these mechanisms, we briefly summarize similarities and differences between these two types of neural cells. We also summarize the changes in the normal migration of OPCs during development that would be relevant for different neurological diseases (including demyelinating diseases, such as multiple sclerosis, and glial cancers). We also examine the relevance of these migratory properties of the oligondendrocytic cell lineage for the repair of neural damage.
Collapse
Affiliation(s)
- Fernando de Castro
- Instituto de Neurociencias de Castilla y León-INCyL, Universidad de Salamanca, Avda. de Alfonso X el Sabio, s/n, E-37007-Salamanca, Spain.
| | | |
Collapse
|
42
|
Stecca B, Ruiz i Altaba A. Brain as a paradigm of organ growth: Hedgehog-Gli signaling in neural stem cells and brain tumors. ACTA ACUST UNITED AC 2005; 64:476-90. [PMID: 16041742 DOI: 10.1002/neu.20160] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The Hedgehog-Gli (Hh-Gli) signaling pathway is essential for numerous events during the development of many animal cell types and organs. In particular, it controls neural cell precursor proliferation in dorsal brain structures and regulates the number of neural stem cells in distinct embryonic, perinatal, and adult niches, such as the developing neocortex, the subventricular zone of the lateral ventricle of the forebrain, and the hippocampus. We have proposed that Hh-Gli signaling regulates dorsal brain growth during ontogeny and that its differential regulation underlays evolutionary change in the morphology (size and shape) of dorsal brain structures. It is also critically involved in sporadic brain tumorigenesis--as well as several other human cancer--suggesting that tumors derive from stem cells or progenitors maintaining an inappropriate active Hh-Gli pathway. Importantly, we and others have demonstrated that human sporadic tumors from the brain and other organs require sustained HH-GLI signaling for sustained growth and survival. Modulating HH-GLI signaling thus represents a novel rational avenue to treat, on one hand, brain degeneration and injury by inducing controlled HH-GLI-mediated regeneration and growth, and on the other hand, to combat cancer by blocking its abnormal activity in tumor cells.
Collapse
Affiliation(s)
- Barbara Stecca
- Department of Genetic Medicine and Development, University of Geneva Medical School, 8242 CMU, 1 rue Michel Servet, CH-1211 Geneva 4, Switzerland
| | | |
Collapse
|
43
|
Shimizu T, Kagawa T, Wada T, Muroyama Y, Takada S, Ikenaka K. Wnt signaling controls the timing of oligodendrocyte development in the spinal cord. Dev Biol 2005; 282:397-410. [PMID: 15950605 DOI: 10.1016/j.ydbio.2005.03.020] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2004] [Revised: 03/17/2005] [Accepted: 03/21/2005] [Indexed: 11/25/2022]
Abstract
During spinal cord development, oligodendrocytes are generated from a restricted region of the ventral ventricular zone and then spread out into the entire spinal cord. These events are controlled by graded inductive and repressive signals derived from a local organizing center. Sonic hedgehog was identified as an essential ventral factor for oligodendrocyte lineage specification, whereas the dorsal cue was less clear. In this study, Wnt proteins were identified as the dorsal factors that directly inhibit oligodendrocyte development. Wnt signaling through a canonical beta-catenin pathway prevents its differentiation from progenitor to an immature state. Addition of rmFz-8/Fc, a Wnt antagonist, increased the number of immature oligodendrocytes in the spinal cord explant culture, demonstrating that endogenous Wnt signaling controls oligodendrocyte development.
Collapse
Affiliation(s)
- Takeshi Shimizu
- Laboratory of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki National Research Institute, Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | | | | | | | | | | |
Collapse
|
44
|
Fogarty M, Richardson WD, Kessaris N. A subset of oligodendrocytes generated from radial glia in the dorsal spinal cord. Development 2005; 132:1951-9. [PMID: 15790969 DOI: 10.1242/dev.01777] [Citation(s) in RCA: 184] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Many oligodendrocytes in the spinal cord are derived from a region of the ventral ventricular zone (VZ) that also gives rise to motoneurons. Cell fate specification in this region depends on sonic hedgehog (Shh) from the notochord and floor plate. There have been suggestions of an additional source(s) of oligodendrocytes in the dorsal spinal cord. We revisited this idea by Cre-lox fate-mapping in transgenic mice. We found that a subpopulation of oligodendrocytes is generated from the Dbx1-expressing domain of the VZ,spanning the dorsoventral midline. Dbx-derived oligodendrocytes comprise less than 5% of the total; they are formed late during embryogenesis by transformation of radial glia and settle mainly in the lateral white matter. Development of Dbx-derived oligodendrocytes in vitro can occur independently of Shh but requires FGF signalling. Dbx-expressing precursors also generate astrocytes and interneurons, but do not contribute to the ependymal layer of the postnatal spinal cord.
Collapse
Affiliation(s)
- Matthew Fogarty
- The Wolfson Institute for Biomedical Research and Department of Biology, University College London (UCL), London, UK
| | | | | |
Collapse
|
45
|
Cai J, Qi Y, Hu X, Tan M, Liu Z, Zhang J, Li Q, Sander M, Qiu M. Generation of oligodendrocyte precursor cells from mouse dorsal spinal cord independent of Nkx6 regulation and Shh signaling. Neuron 2005; 45:41-53. [PMID: 15629701 DOI: 10.1016/j.neuron.2004.12.028] [Citation(s) in RCA: 244] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2004] [Revised: 10/07/2004] [Accepted: 11/16/2004] [Indexed: 02/07/2023]
Abstract
In the developing spinal cord, early progenitor cells of the oligodendrocyte lineage are induced in the motor neuron progenitor (pMN) domain of the ventral neuroepithelium by the ventral midline signal Sonic hedgehog (Shh). The ventral generation of oligodendrocytes requires Nkx6-regulated expression of the bHLH gene Olig2 in this domain. In the absence of Nkx6 genes or Shh signaling, the initial expression of Olig2 in the pMN domain is completely abolished. In this study, we provide the in vivo evidence for a late phase of Olig gene expression independent of Nkx6 and Shh gene activities and reveal a brief second wave of oligodendrogenesis in the dorsal spinal cord. In addition, we provide genetic evidence that oligodendrogenesis can occur in the absence of hedgehog receptor Smoothened, which is essential for all hedgehog signaling.
Collapse
Affiliation(s)
- Jun Cai
- Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY 40292, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Zhang X, Cai J, Klueber KM, Guo Z, Lu C, Qiu M, Roisen FJ. Induction of Oligodendrocytes From Adult Human Olfactory Epithelial-Derived Progenitors by Transcription Factors. Stem Cells 2005; 23:442-53. [PMID: 15749939 DOI: 10.1634/stemcells.2004-0274] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Neurosphere-forming cell (NSFC) lines have been derived from cultures of adult olfactory neuroepithelium obtained from patients and cadavers. These progenitors remain undifferentiated when maintained in minimal essential medium with 10% fetal bovine serum, but have the potential to differentiate along glial or neuronal lineages. However, few of these cells ever express mature neuronal or glial markers in defined medium. To evaluate the potential of NSFCs to form oligodendrocytes, two transcription factors, Olig2 and Nkx2.2, were introduced into NSFCs to determine whether their expression is sufficient for oligodendrocyte differentiation, as has been shown in the embryonic avian and murine central nervous systems in vivo. NSFCs transfected with Olig2 or Nkx2.2 alone exhibited no phenotypic lineage restriction. In contrast, simultaneous transfection of Olig2 and Nkx2.2 cDNA produced characteristic oligodendrocyte morphology and antigenicity, including myelin basic protein (MBP). Furthermore, a population of Olig2-expressing NSFCs also expressed Sox10. Cotransfection of NSFCs with Nkx2.2 and Sox10, but not Olig2 and Sox10, produced a MBP(+) oligodendrocytic phenotype. Coculture of NSFCs transfected with Olig2 and Nkx2.2 or Nkx2.2 and Sox10 with purified sensory neurons, demonstrated frequent contacts between NSFC processes and axons, including the early stages of ensheathment. These studies demonstrate transcription factors governing early development of chick and mouse oligodendrocyte formation, also apply to human progenitors isolated from adult olfactory neuroepithelium. Our long-term goal is to develop cell populations for future studies used to determine the therapeutic utility of these olfactory-derived NSFCs for autologous transplantation into donors with central nervous system trauma or neurodegenerative diseases.
Collapse
Affiliation(s)
- Xiaodong Zhang
- Department of Anatomical Sciences and Neurobiology, University of Louisville, School of Medicine, Louisville, Kentucky 40202, USA
| | | | | | | | | | | | | |
Collapse
|
47
|
Samanta J, Kessler JA. Interactions between ID and OLIG proteins mediate the inhibitory effects of BMP4 on oligodendroglial differentiation. Development 2004; 131:4131-42. [PMID: 15280210 DOI: 10.1242/dev.01273] [Citation(s) in RCA: 279] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Bone morphogenetic protein (BMP) signaling inhibits the generation of oligodendroglia and enhances generation of astrocytes by neural progenitor cells both in vitro and in vivo. This study examined the mechanisms underlying the effects of BMP signaling on glial lineage commitment. Treatment of cultured neural progenitor cells with BMP4 induced expression of all four members of the inhibitor of differentiation (ID) family of helix-loop-helix transcriptional inhibitors and blocked oligodendrocyte (OL) lineage commitment. Overexpression of Id4 or Id2 but not Id1 or Id3 in cultured progenitor cells reproduced both the inhibitory effects of BMP4 treatment on OL lineage commitment and the stimulatory effects on astrogliogenesis. Conversely, decreasing the levels of Id4 mRNA by RNA interference enhanced OL differentiation and inhibited the effects of BMP4 on glial lineage commitment. This suggests that induction of Id4 expression mediates effects of BMP signaling. Bacterial two-hybrid and co-immunoprecipitation studies demonstrated that ID4,and to a lesser extent ID2, complexed with the basic-helix-loop-helix transcription (bHLH) factors OLIG1 and OLIG2, which are required for the generation of OLs. By contrast, ID1 and ID3 did not complex with the OLIG proteins. In addition, the OLIG and ID proteins both interacted with the E2A proteins E12 and E47. Further, exposure of cultured progenitor cells to BMP4 changed the intracellular localization of OLIG1 and OLIG2 from a predominantly nuclear to a predominantly cytoplasmic localization. These observations suggest that the induction of ID4 and ID2, and their sequestration of both OLIG proteins and E2A proteins mediate the inhibitory effects of BMP signaling on OL lineage commitment and contribute to the generation of astrocytes.
Collapse
Affiliation(s)
- Jayshree Samanta
- Northwestern University's Feinberg School of Medicine, Department of Neurology, Chicago, IL 60611, USA
| | | |
Collapse
|
48
|
Agius E, Soukkarieh C, Danesin C, Kan P, Takebayashi H, Soula C, Cochard P. Converse control of oligodendrocyte and astrocyte lineage development by Sonic hedgehog in the chick spinal cord. Dev Biol 2004; 270:308-21. [PMID: 15183716 DOI: 10.1016/j.ydbio.2004.02.015] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2003] [Revised: 02/18/2004] [Accepted: 02/18/2004] [Indexed: 11/28/2022]
Abstract
In the developing spinal cord, oligodendrocyte progenitors (OLPs) originate from the ventral neuroepithelium and the specification of this lineage depends on the inductive activity of Sonic hedgehog (Shh) produced by ventral midline cells. On the other hand, it has been shown that OLP identity is acquired by the coexpression of the transcription factors olig2 and nkx2.2. Although initially expressed in adjacent nonoverlapping domains of the ventral neuroepithelium, these transcription factors become coexpressed in the pMN domain at the time of OLP specification through dorsal extension of the Nkx2.2 domain. Here we show that Shh is sufficient to promote the coexpression of Olig2 and Nkx2.2 in neuroepithelial cells. In addition, Shh activity is necessary for this coexpression since blocking Shh signalling totally abolishes Olig2 expression and impedes dorsal extension of Nkx2.2. Although Shh at these stages affects neuroepithelial cell proliferation, the dorsal extension of the Nkx2.2 domain is not due to progenitor proliferation but to repatterning of the ventral neuroepithelium. Finally, Shh not only stimulates OLP specification but also simultaneously restricts the ventral extension of the astrocyte progenitor (AP) domain and reduces astrocyte development. We propose that specification of distinct glial lineages is the result of a choice that depends on Shh signalling.
Collapse
Affiliation(s)
- Eric Agius
- Centre de Biologie du Développement, UMR5547 CNRS/UPS, Université Paul Sabatier, Toulouse, France.
| | | | | | | | | | | | | |
Collapse
|
49
|
See J, Zhang X, Eraydin N, Mun SB, Mamontov P, Golden JA, Grinspan JB. Oligodendrocyte maturation is inhibited by bone morphogenetic protein. Mol Cell Neurosci 2004; 26:481-92. [PMID: 15276151 DOI: 10.1016/j.mcn.2004.04.004] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2003] [Revised: 04/07/2004] [Accepted: 04/12/2004] [Indexed: 11/28/2022] Open
Abstract
Mature oligodendrocytes myelinate axons in the CNS. The development of the myelin sheath is dependent on the proper maturation of oligodendrocytes from precursors cells, a spatially restricted process that is regulated by inductive and repressive cues. Several members of the bone morphogenetic protein family (BMP2 and 4) have been implicated as repressors of oligodendrocyte development in vitro by shifting oligodendrocyte precursors into the astrocyte lineage. We now report on a second role of BMPs in oligodendrocyte development, regulation of myelin protein expression in immature oligodendrocytes. Purified immature rodent oligodendrocytes treated with BMP4 maintained galactocerebroside (GalC) expression, whereas the expression of three key myelin proteins, proteolipid protein (PLP), myelin basic protein (MBP), and 2'-3'-cyclic nucleotide 3'-phosphodiesterase (CNP), was severely decreased. Paradoxically, BMP-treated oligodendrocytes show increased process extension and complexity, normally a feature of oligodendrocyte maturation. We also investigated whether BMP4 could inhibit myelin protein expression in an E 12.5 mouse explant culture of cervical spinal cord and hindbrain that maintains the in vivo cellular relationships and architecture. Beads soaked in BMP protein implanted into these explants inhibited the expression of myelin proteins, proteolipid protein, and myelin-associated glycoprotein (MAG), in the local area surrounding the bead. Since these explants also contained precursors cells, expression of galactocerebroside and O4, an oligodendrocyte marker, were also decreased by BMP treatment but to a much lesser degree than the myelin markers. Together, these data indicate that BMPs have multiple roles in oligodendrocyte development. At earlier stages, they affect cell lineage decisions and at later stages, they inhibit cell specialization.
Collapse
Affiliation(s)
- Jill See
- Department of Research Neurology, Children's Hospital of Philadelphia, 516D Abramson Center, Philadelphia, PA 19104, USA
| | | | | | | | | | | | | |
Collapse
|
50
|
Affiliation(s)
- David H Rowitch
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.
| |
Collapse
|