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Nocera S, Marchena MA, Fernández-Gómez B, Gómez-Martín P, Sánchez-Jiménez E, Macías-Castellano A, Laó Y, Cordano C, Gómez-Torres Ó, Luján R, de Castro F. Activation of Shh/Smo is sufficient to maintain oligodendrocyte precursor cells in an undifferentiated state and is not necessary for myelin formation and (re)myelination. Glia 2024. [PMID: 38771121 DOI: 10.1002/glia.24540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 05/22/2024]
Abstract
Myelination is the terminal step in a complex and precisely timed program that orchestrates the proliferation, migration and differentiation of oligodendroglial cells. It is thought that Sonic Hedgehog (Shh) acting on Smoothened (Smo) participates in regulating this process, but that these effects are highly context dependent. Here, we investigate oligodendroglial development and remyelination from three specific transgenic lines: NG2-CreERT2 (control), Smofl/fl/NG2-CreERT2 (loss of function), and SmoM2/NG2-CreERT2 (gain of function), as well as pharmacological manipulation that enhance or inhibit the Smo pathway (Smoothened Agonist (SAG) or cyclopamine treatment, respectively). To explore the effects of Shh/Smo on differentiation and myelination in vivo, we developed a highly quantifiable model by transplanting oligodendrocyte precursor cells (OPCs) in the retina. We find that myelination is greatly enhanced upon cyclopamine treatment and hypothesize that Shh/Smo could promote OPC proliferation to subsequently inhibit differentiation. Consistent with this hypothesis, we find that the genetic activation of Smo significantly increased numbers of OPCs and decreased oligodendrocyte differentiation when we examined the corpus callosum during development and after cuprizone demyelination and remyelination. However, upon loss of function with the conditional ablation of Smo, myelination in the same scenarios are unchanged. Taken together, our present findings suggest that the Shh pathway is sufficient to maintain OPCs in an undifferentiated state, but is not necessary for myelination and remyelination.
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Affiliation(s)
- Sonia Nocera
- Grupo de Neurobiología del Desarrollo-GNDe, Instituto Cajal-CSIC, Madrid, Spain
| | - Miguel A Marchena
- Grupo de Neurobiología del Desarrollo-GNDe, Instituto Cajal-CSIC, Madrid, Spain
- Facultad HM de Ciencias de la Salud de la UCJC, Universidad Camilo José Cela, Madrid, Spain
- NeuroLab, Instituto de Investigación Sanitaria HM Hospitales, Madrid, Spain
| | | | - Paula Gómez-Martín
- Grupo de Neurobiología del Desarrollo-GNDe, Instituto Cajal-CSIC, Madrid, Spain
| | | | | | - Yolanda Laó
- Grupo de Neurobiología del Desarrollo-GNDe, Instituto Cajal-CSIC, Madrid, Spain
| | - Christian Cordano
- Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, California, USA
- Department of Neurology, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health. University of Genoa, Italy
- Department of Neuroscience, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Óscar Gómez-Torres
- Facultad de Ciencias Ambientales, Universidad de Castilla-La Mancha, Toledo, Spain
| | - Rafael Luján
- Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Fernando de Castro
- Grupo de Neurobiología del Desarrollo-GNDe, Instituto Cajal-CSIC, Madrid, Spain
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Russo M, Pellegrino G, Faure H, Tirou L, Sharif A, Ruat M. Characterization of Sonic Hedgehog transcripts in the adult mouse brain: co-expression with neuronal and oligodendroglial markers. Brain Struct Funct 2024; 229:705-727. [PMID: 38329543 PMCID: PMC10978748 DOI: 10.1007/s00429-023-02756-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 12/29/2023] [Indexed: 02/09/2024]
Abstract
In the adult mammalian brain, astrocytes are proposed to be the major Sonic Hedgehog (Shh)-responsive cells. However, the sources of the Shh molecule mediating activation of the pathway are still poorly characterized. The present work investigates the distribution and phenotype of cells expressing Shh mRNA in the adult mouse brain. Using single-molecule fluorescent in situ hybridization (smfISH), we report much broader expression of Shh transcripts in almost all brain regions than originally reported. We identify Shh mRNA in HuC/D+ neuronal populations, including GABAergic (glutamic acid decarboxylase 67, Gad67), cholinergic (choline acetyltransferase, ChAT), dopaminergic (tyrosine hydroxylase, TH), nitrergic (neuronal nitric oxide synthase, nNOS), and in a small population of oligodendroglial cells expressing Sox10 and Olig2 mRNA transcription factors. Further analysis of Shh mRNA in cerebral cortical and hypothalamic neurons suggests that Shh is also expressed by glutamatergic neurons. Interestingly, we did not observe substantial Desert Hedgehog and Indian Hedgehog mRNA signals, nor Shh signals in S100β+ astrocytes and Iba1+ microglial cells. Collectively, the present work provides the most robust central map of Shh-expressing cells to date and underscores the importance of nitrergic neurons in regulating Shh availability to brain cells. Thus, our study provides a framework for future experiments aimed at better understanding of the functions of Shh signaling in the brain in normal and pathological states, and the characterization of novel regulatory mechanisms of the signaling pathway.
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Affiliation(s)
- Mariagiovanna Russo
- CNRS, Paris-Saclay University, UMR-9197, Neuroscience Paris-Saclay Institute, 91400, Saclay, France
| | - Giuliana Pellegrino
- CNRS, Paris-Saclay University, UMR-9197, Neuroscience Paris-Saclay Institute, 91400, Saclay, France
| | - Hélène Faure
- CNRS, Paris-Saclay University, UMR-9197, Neuroscience Paris-Saclay Institute, 91400, Saclay, France
| | - Linda Tirou
- CNRS, Paris-Saclay University, UMR-9197, Neuroscience Paris-Saclay Institute, 91400, Saclay, France
| | - Ariane Sharif
- Univ. Lille, Inserm, CHU Lille, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Lille Neuroscience and Cognition, UMR-S 1172, FHU 1000 Days for Health, Lille, France
| | - Martial Ruat
- CNRS, Paris-Saclay University, UMR-9197, Neuroscience Paris-Saclay Institute, 91400, Saclay, France.
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Dominicis A, Del Giovane A, Torreggiani M, Recchia AD, Ciccarone F, Ciriolo MR, Ragnini-Wilson A. N-Acetylaspartate Drives Oligodendroglial Differentiation via Histone Deacetylase Activation. Cells 2023; 12:1861. [PMID: 37508525 PMCID: PMC10378218 DOI: 10.3390/cells12141861] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/09/2023] [Accepted: 07/12/2023] [Indexed: 07/30/2023] Open
Abstract
An unmet clinical goal in demyelinating pathologies is to restore the myelin sheath prior to neural degeneration. N-acetylaspartate (NAA) is an acetylated derivative form of aspartate, abundant in the healthy brain but severely reduced during traumatic brain injury and in patients with neurodegenerative pathologies. How extracellular NAA variations impact the remyelination process and, thereby, the ability of oligodendrocytes to remyelinate axons remains unexplored. Here, we evaluated the remyelination properties of the oligodendroglial (OL) mouse cell line Oli-neuM under different concentrations of NAA using a combination of biochemical, qPCR, immunofluorescence assays, and in vitro engagement tests, at NAA doses compatible with those observed in healthy brains and during brain injury. We observed that oligodendroglia cells respond to decreasing levels of NAA by stimulating differentiation and promoting gene expression of myelin proteins in a temporally regulated manner. Low doses of NAA potently stimulate Oli-neuM to engage with synthetic axons. Furthermore, we show a concentration-dependent expression of specific histone deacetylases essential for MBP gene expression under NAA or Clobetasol treatment. These data are consistent with the idea that oligodendrocytes respond to lowering the NAA concentration by activating the remyelination process via deacetylase activation.
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Affiliation(s)
| | - Alice Del Giovane
- Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Matteo Torreggiani
- Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy
| | | | - Fabio Ciccarone
- Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy
- IRCCS San Raffaele, 00166 Rome, Italy
| | - Maria Rosa Ciriolo
- Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy
- IRCCS San Raffaele, 00166 Rome, Italy
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Fang M, Tang T, Qiu M, Xu X. Hedgehog Signaling in CNS Remyelination. Cells 2022; 11:cells11142260. [PMID: 35883703 PMCID: PMC9320235 DOI: 10.3390/cells11142260] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/14/2022] [Accepted: 07/20/2022] [Indexed: 12/14/2022] Open
Abstract
Remyelination is a fundamental repair process in the central nervous system (CNS) that is triggered by demyelinating events. In demyelinating diseases, oligodendrocytes (OLs) are targeted, leading to myelin loss, axonal damage, and severe functional impairment. While spontaneous remyelination often fails in the progression of demyelinating diseases, increased understanding of the mechanisms and identification of targets that regulate myelin regeneration becomes crucial. To date, several signaling pathways have been implicated in the remyelination process, including the Hedgehog (Hh) signaling pathway. This review summarizes the current data concerning the complicated roles of the Hh signaling pathway in the context of remyelination. We will highlight the open issues that have to be clarified prior to bringing molecules targeting the Hh signaling to demyelinating therapy.
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Affiliation(s)
- Minxi Fang
- Institute of Life Sciences, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 311121, China;
- College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Tao Tang
- Department of Anatomy, Cell Biology & Physiology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA;
| | - Mengsheng Qiu
- Institute of Life Sciences, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 311121, China;
- College of Life Sciences, Zhejiang University, Hangzhou 310058, China
- School of Basic Medicial Sciences, Hangzhou Normal University, Hangzhou 311121, China
- Correspondence: (M.Q.); (X.X.)
| | - Xiaofeng Xu
- Institute of Life Sciences, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 311121, China;
- Correspondence: (M.Q.); (X.X.)
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