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Romanyuk N, Sintakova K, Arzhanov I, Horak M, Gandhi C, Jhanwar-Uniyal M, Jendelova P. mTOR pathway inhibition alters proliferation as well as differentiation of neural stem cells. Front Cell Neurosci 2024; 18:1298182. [PMID: 38812794 PMCID: PMC11133533 DOI: 10.3389/fncel.2024.1298182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 04/23/2024] [Indexed: 05/31/2024] Open
Abstract
Introduction Neural stem cells (NSCs) are essential for both embryonic development and adult neurogenesis, and their dysregulation causes a number of neurodevelopmental disorders, such as epilepsy and autism spectrum disorders. NSC proliferation and differentiation in the developing brain is a complex process controlled by various intrinsic and extrinsic stimuli. The mammalian target of rapamycin (mTOR) regulates proliferation and differentiation, among other cellular functions, and disruption in the mTOR pathway can lead to severe nervous system development deficits. In this study, we investigated the effect of inhibition of the mTOR pathway by rapamycin (Rapa) on NSC proliferation and differentiation. Methods The NSC cultures were treated with Rapa for 1, 2, 6, 24, and 48 h. The effect on cellular functions was assessed by immunofluorescence staining, western blotting, and proliferation/metabolic assays. Results mTOR inhibition suppressed NSC proliferation/metabolic activity as well as S-Phase entry by as early as 1 h of Rapa treatment and this effect persisted up to 48 h of Rapa treatment. In a separate experiment, NSCs were differentiated for 2 weeks after treatment with Rapa for 24 or 48 h. Regarding the effect on neuronal and glial differentiation (2 weeks post-treatment), this was suppressed in NSCs deficient in mTOR signaling, as evidenced by downregulated expression of NeuN, MAP2, and GFAP. We assume that the prolonged effect of mTOR inhibition is realized due to the effect on cytoskeletal proteins. Discussion Here, we demonstrate for the first time that the mTOR pathway not only regulates NSC proliferation but also plays an important role in NSC differentiation into both neuronal and glial lineages.
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Affiliation(s)
- Nataliya Romanyuk
- Department of Neuroregeneration, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
| | - Kristyna Sintakova
- Department of Neuroregeneration, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
- Department of Neuroscience, Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Ivan Arzhanov
- Department of Neuroregeneration, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
- Department of Neuroscience, Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Martin Horak
- Department of Neurochemistry, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
| | - Chirag Gandhi
- Department of Neurosurgery, New York Medical College, Valhalla, NY, United States
| | - Meena Jhanwar-Uniyal
- Department of Neurosurgery, New York Medical College, Valhalla, NY, United States
| | - Pavla Jendelova
- Department of Neuroregeneration, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
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Garone C, De Giorgio F, Carli S. Mitochondrial metabolism in neural stem cells and implications for neurodevelopmental and neurodegenerative diseases. J Transl Med 2024; 22:238. [PMID: 38438847 PMCID: PMC10910780 DOI: 10.1186/s12967-024-05041-w] [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: 12/29/2023] [Accepted: 02/25/2024] [Indexed: 03/06/2024] Open
Abstract
Mitochondria are cytoplasmic organelles having a fundamental role in the regulation of neural stem cell (NSC) fate during neural development and maintenance.During embryonic and adult neurogenesis, NSCs undergo a metabolic switch from glycolytic to oxidative phosphorylation with a rise in mitochondrial DNA (mtDNA) content, changes in mitochondria shape and size, and a physiological augmentation of mitochondrial reactive oxygen species which together drive NSCs to proliferate and differentiate. Genetic and epigenetic modifications of proteins involved in cellular differentiation (Mechanistic Target of Rapamycin), proliferation (Wingless-type), and hypoxia (Mitogen-activated protein kinase)-and all connected by the common key regulatory factor Hypoxia Inducible Factor-1A-are deemed to be responsible for the metabolic shift and, consequently, NSC fate in physiological and pathological conditions.Both primary mitochondrial dysfunction due to mutations in nuclear DNA or mtDNA or secondary mitochondrial dysfunction in oxidative phosphorylation (OXPHOS) metabolism, mitochondrial dynamics, and organelle interplay pathways can contribute to the development of neurodevelopmental or progressive neurodegenerative disorders.This review analyses the physiology and pathology of neural development starting from the available in vitro and in vivo models and highlights the current knowledge concerning key mitochondrial pathways involved in this process.
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Affiliation(s)
- C Garone
- Department of Medical and Surgical Sciences, Alma Mater Studiorum-University of Bologna, Bologna, Italy.
- IRCCS Istituto Delle Scienze Neurologiche di Bologna, UO Neuropsichiatria Dell'età Pediatrica, Bologna, Italy.
| | - F De Giorgio
- Department of Medical and Surgical Sciences, Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | - S Carli
- Department of Medical and Surgical Sciences, Alma Mater Studiorum-University of Bologna, Bologna, Italy
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3
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Rodríguez-Moreno CB, Cañeque-Rufo H, Flor-García M, Terreros-Roncal J, Moreno-Jiménez EP, Pallas-Bazarra N, Bressa C, Larrosa M, Cafini F, Llorens-Martín M. Azithromycin preserves adult hippocampal neurogenesis and behavior in a mouse model of sepsis. Brain Behav Immun 2024; 117:135-148. [PMID: 38211636 PMCID: PMC7615685 DOI: 10.1016/j.bbi.2024.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 12/11/2023] [Accepted: 01/08/2024] [Indexed: 01/13/2024] Open
Abstract
The mammalian hippocampus can generate new neurons throughout life. Known as adult hippocampal neurogenesis (AHN), this process participates in learning, memory, mood regulation, and forgetting. The continuous incorporation of new neurons enhances the plasticity of the hippocampus and contributes to the cognitive reserve in aged individuals. However, the integrity of AHN is targeted by numerous pathological conditions, including neurodegenerative diseases and sustained inflammation. In this regard, the latter causes cognitive decline, mood alterations, and multiple AHN impairments. In fact, the systemic administration of Lipopolysaccharide (LPS) from E. coli to mice (a model of sepsis) triggers depression-like behavior, impairs pattern separation, and decreases the survival, maturation, and synaptic integration of adult-born hippocampal dentate granule cells. Here we tested the capacity of the macrolide antibiotic azithromycin to neutralize the deleterious consequences of LPS administration in female C57BL6J mice. This antibiotic exerted potent neuroprotective effects. It reversed the increased immobility time during the Porsolt test, hippocampal secretion of pro-inflammatory cytokines, and AHN impairments. Moreover, azithromycin promoted the synaptic integration of adult-born neurons and functionally remodeled the gut microbiome. Therefore, our data point to azithromycin as a clinically relevant drug with the putative capacity to ameliorate the negative consequences of chronic inflammation by modulating AHN and hippocampal-related behaviors.
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Affiliation(s)
- Carla B Rodríguez-Moreno
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain; Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Héctor Cañeque-Rufo
- Department of Chemistry and Biochemistry, School of Pharmacy, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28660 Boadilla del Monte, Spain; Department of Health and Pharmaceutical Sciences, School of Pharmacy, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28660 Boadilla del Monte, Spain
| | - Miguel Flor-García
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain; Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain; Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - Julia Terreros-Roncal
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain; Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain; Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - Elena P Moreno-Jiménez
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain; Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain; Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - Noemí Pallas-Bazarra
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK; MRC Centre for Neurodevelopmental Disorders, King's College London, London SE1 1UL, UK
| | - Carlo Bressa
- Facultad de Ciencias Experimentales, Universidad Francisco de Vitoria, Ctra. Pozuelo-Majadahonda Km 1,800, 28223, Pozuelo de Alarcón, Madrid
| | - Mar Larrosa
- Department of Food Science and Nutrition, Faculty of Pharmacy, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Fabio Cafini
- Faculty of Biomedical and Health Sciences, Universidad Europea de Madrid, Madrid, Spain.
| | - María Llorens-Martín
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain; Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain.
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Jhanwar-Uniyal M, Zeller SL, Spirollari E, Das M, Hanft SJ, Gandhi CD. Discrete Mechanistic Target of Rapamycin Signaling Pathways, Stem Cells, and Therapeutic Targets. Cells 2024; 13:409. [PMID: 38474373 DOI: 10.3390/cells13050409] [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: 01/16/2024] [Revised: 02/14/2024] [Accepted: 02/22/2024] [Indexed: 03/14/2024] Open
Abstract
The mechanistic target of rapamycin (mTOR) is a serine/threonine kinase that functions via its discrete binding partners to form two multiprotein complexes, mTOR complex 1 and 2 (mTORC1 and mTORC2). Rapamycin-sensitive mTORC1, which regulates protein synthesis and cell growth, is tightly controlled by PI3K/Akt and is nutrient-/growth factor-sensitive. In the brain, mTORC1 is also sensitive to neurotransmitter signaling. mTORC2, which is modulated by growth factor signaling, is associated with ribosomes and is insensitive to rapamycin. mTOR regulates stem cell and cancer stem cell characteristics. Aberrant Akt/mTOR activation is involved in multistep tumorigenesis in a variety of cancers, thereby suggesting that the inhibition of mTOR may have therapeutic potential. Rapamycin and its analogues, known as rapalogues, suppress mTOR activity through an allosteric mechanism that only suppresses mTORC1, albeit incompletely. ATP-catalytic binding site inhibitors are designed to inhibit both complexes. This review describes the regulation of mTOR and the targeting of its complexes in the treatment of cancers, such as glioblastoma, and their stem cells.
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Affiliation(s)
- Meena Jhanwar-Uniyal
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Sabrina L Zeller
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Eris Spirollari
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Mohan Das
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Simon J Hanft
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Chirag D Gandhi
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
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Geben LC, Brockman AA, Chalkley MBL, Sweet SR, Gallagher JE, Scheuing AL, Simerly RB, Ess KC, Irish JM, Ihrie RA. Dephosphorylation of 4EBP1/2 Induces Prenatal Neural Stem Cell Quiescence. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.14.528513. [PMID: 36824760 PMCID: PMC9948964 DOI: 10.1101/2023.02.14.528513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
A limiting factor in the regenerative capacity of the adult brain is the abundance and proliferative ability of neural stem cells (NSCs). Adult NSCs are derived from a subpopulation of embryonic NSCs that temporarily enter quiescence during mid-gestation and remain quiescent until postnatal reactivation. Here we present evidence that the mechanistic/mammalian target of rapamycin (mTOR) pathway regulates quiescence entry in embryonic NSCs of the developing forebrain. Throughout embryogenesis, two downstream effectors of mTOR, p-4EBP1/2 T37/46 and p-S6 S240/244, were mutually exclusive in NSCs, rarely occurring in the same cell. While 4EBP1/2 was phosphorylated in stem cells undergoing mitosis at the ventricular surface, S6 was phosphorylated in more differentiated cells migrating away from the ventricle. Phosphorylation of 4EBP1/2, but not S6, was responsive to quiescence induction in cultured embryonic NSCs. Further, inhibition of p-4EBP1/2, but not p-S6, was sufficient to induce quiescence. Collectively, this work offers new insight into the regulation of quiescence entry in embryonic NSCs and, thereby, correct patterning of the adult brain. These data suggest unique biological functions of specific posttranslational modifications and indicate that the preferential inhibition of such modifications may be a useful therapeutic approach in neurodevelopmental diseases where NSC numbers, proliferation, and differentiation are altered.
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Affiliation(s)
- Laura C. Geben
- Program in Pharmacology, Vanderbilt University, Nashville, TN, 37235, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37235, USA
| | - Asa A. Brockman
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37235, USA
| | | | - Serena R. Sweet
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37235, USA
| | - Julia E. Gallagher
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37235, USA
| | - Alexandra L. Scheuing
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37235, USA
| | - Richard B. Simerly
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37235, USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville TN 37235, USA
| | - Kevin C. Ess
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37235, USA
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37235, USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville TN 37235, USA
| | - Jonathan M. Irish
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37235, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37235, USA
- Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN 37235, USA
| | - Rebecca A. Ihrie
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37235, USA
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN 37235, USA
- Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN 37235, USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville TN 37235, USA
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6
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Wang R, Amoyel M. mRNA Translation Is Dynamically Regulated to Instruct Stem Cell Fate. Front Mol Biosci 2022; 9:863885. [PMID: 35433828 PMCID: PMC9008482 DOI: 10.3389/fmolb.2022.863885] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 02/25/2022] [Indexed: 12/12/2022] Open
Abstract
Stem cells preserve tissue homeostasis by replacing the cells lost through damage or natural turnover. Thus, stem cells and their daughters can adopt two identities, characterized by different programs of gene expression and metabolic activity. The composition and regulation of these programs have been extensively studied, particularly by identifying transcription factor networks that define cellular identity and the epigenetic changes that underlie the progressive restriction in gene expression potential. However, there is increasing evidence that post-transcriptional mechanisms influence gene expression in stem cells and their progeny, in particular through the control of mRNA translation. Here, we review the described roles of translational regulation in controlling all aspects of stem cell biology, from the decision to enter or exit quiescence to maintaining self-renewal and promoting differentiation. We focus on mechanisms controlling global translation rates in cells, mTOR signaling, eIF2ɑ phosphorylation, and ribosome biogenesis and how they allow stem cells to rapidly change their gene expression in response to tissue needs or environmental changes. These studies emphasize that translation acts as an additional layer of control in regulating gene expression in stem cells and that understanding this regulation is critical to gaining a full understanding of the mechanisms that underlie fate decisions in stem cells.
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Affiliation(s)
| | - Marc Amoyel
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
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Colucci-D'Amato L, Cimaglia G. Ruta graveolens as a potential source of neuroactive compounds to promote and restore neural functions. J Tradit Complement Med 2020; 10:309-314. [PMID: 32670826 PMCID: PMC7340976 DOI: 10.1016/j.jtcme.2020.05.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/22/2020] [Accepted: 05/22/2020] [Indexed: 11/21/2022] Open
Abstract
Nutraceuticals had always been known for their therapeutic effects in ancient medicine and had been the primary healing remedy until the introduction of modern chemistry and pharmacology. However, their use has not been dismissed but actually is acquiring a new acclamation among the scientific community especially for their efficacy on the Central Nervous System (CNS). Molecular mechanisms of the most common neurodegenerative diseases are now being uncovered and along with that the molecules that drive the neurodegenerative processes. It is not surprising that some natural compounds can interact with those molecules and interfere with the pathological pathways halting the cascades that ultimately lead to neuronal cell death. The plant Ruta graveolens has gained increased attention in medicinal chemistry due to its beneficial role to treat a variety of human diseases and also because of the presence of a huge number of compounds belonging to different classes of natural products, including neuroactive compounds potentially able to promote neuroprotection. Among all the components of the plant extract, rutin – which is highly, if not the most, abundant – positively interacts with the neurophysiology of the CNS too, being particularly efficient against neurotoxicity. Rutin, has proven to be protective in a variety of experimental settings of neurodegeneration. Finally, it has been shown that the water extract of Ruta graveolens (RGWE) induces death of glioblastoma cells but not of neuronal cells. Moreover, it also fosters cell cycle re-entry and differentiation of neuronal cells. This peculiarity represents a promising tool to promote neural plasticity in pathological conditions. Traditional therapeutic use of the plant Ruta graveolens in a large variety of illnesses. It has been used, together with its main component rutin to treat some neurodegenerative diseases. It might own compounds able to foster plasticity in neural cells. It is able to kill neural cancer cells but not neurons.
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Affiliation(s)
- Luca Colucci-D'Amato
- Department of Environmental, Biological and Pharmaceutical Science and Technology (DiSTABiF), University of Campania "L. Vanvitelli", Caserta, Italy.,InterUniversity Center for Research in Neuroscience (CIRN), Napoli, Italy
| | - Gloria Cimaglia
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK.,Department of Clinical Neuroscience, Karoliska Institutet, Stockholm, Sweden
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Postnatal skeletal growth is driven by the epiphyseal stem cell niche: potential implications to pediatrics. Pediatr Res 2020; 87:986-990. [PMID: 31830758 PMCID: PMC7196937 DOI: 10.1038/s41390-019-0722-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 10/31/2019] [Accepted: 12/03/2019] [Indexed: 12/23/2022]
Abstract
Children's longitudinal growth is facilitated by the activity of the growth plates, cartilage discs located near the ends of the long-bones. In order to elongate these bones, growth plates must continuously generate chondrocytes. Two recent studies have demonstrated that there are stem cells and a stem cell niche in the growth plate, which govern the generation of chondrocytes during the postnatal growth period. The niche, which allows stem cells to renew, appears at the same time as the secondary ossification center (SOC) matures into a bone epiphysis. Thus, the mechanism of chondrocyte generation differs substantially between neonatal and postnatal age, i.e., before and after the formation of the mineralized epiphyses. Hence, at the neonatal age bone growth is based on a consumption of chondro-progenitors whereas postnatally it is based on the activity of the stem cell niche. Here we discuss potential implications of these observations in relation to longitudinal growth, including the effects of estrogens, nutrition and growth hormone.
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Translating neural stem cells to neurons in the mammalian brain. Cell Death Differ 2019; 26:2495-2512. [PMID: 31551564 DOI: 10.1038/s41418-019-0411-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 07/05/2019] [Accepted: 08/08/2019] [Indexed: 02/07/2023] Open
Abstract
The mammalian neocortex underlies our perception of sensory information, performance of motor activities, and higher-order cognition. During mammalian embryogenesis, radial glial precursor cells sequentially give rise to diverse populations of excitatory cortical neurons, followed by astrocytes and oligodendrocytes. A subpopulation of these embryonic neural precursors persists into adulthood as neural stem cells, which give rise to inhibitory interneurons and glia. Although the intrinsic mechanisms instructing the genesis of these distinct progeny have been well-studied, most work to date has focused on transcriptional, epigenetic, and cell-cycle control. Recent studies, however, have shown that posttranscriptional mechanisms also regulate the cell fate choices of transcriptionally primed neural precursors during cortical development. These mechanisms are mediated primarily by RNA-binding proteins and microRNAs that coordinately regulate mRNA translation, stability, splicing, and localization. Together, these findings point to an extensive network of posttranscriptional control and provide insight into both normal cortical development and disease. They also add another layer of complexity to brain development and raise important biological questions for future investigation.
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Romer-Seibert JS, Hartman NW, Moss EG. The RNA-binding protein LIN28 controls progenitor and neuronal cell fate during postnatal neurogenesis. FASEB J 2018; 33:3291-3303. [PMID: 30423261 PMCID: PMC6404560 DOI: 10.1096/fj.201801118r] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The RNA-binding protein LIN28 is known to regulate cell fate, tissue growth, and pluripotency; however, a unified understanding of its role at the cellular level has not been achieved. Here, we address its developmental activity in mammalian postnatal neurogenesis. Constitutive expression of LIN28 in progenitor cells of the mouse subventricular zone (SVZ) caused several distinct effects: 1) the number of differentiated neurons in the olfactory bulb was dramatically reduced, whereas the relative abundance of 2 neuronal subtypes was significantly altered, 2) the population of proliferating neural progenitors in the SVZ was reduced, whereas the proportion of neuroblasts was increased, and 3) the number of astrocytes was reduced, occasionally causing them to appear early. Thus, LIN28 acts at a poststem cell/predifferentiation step, and its continuous expression caused a precocious phenotype unlike in other experimental systems. Furthermore, for the first time in a vertebrate system, we separate the majority of the biologic role of LIN28 from its known activity of blocking the microRNA let-7 by using a circular RNA sponge. We find that although LIN28 has a multifaceted role in the number and types of cells produced during postnatal neurogenesis, it appears that its action through let-7 is responsible for only a fraction of these effects.—Romer-Seibert, J. S., Hartman, N. W., Moss, E. G. The RNA-binding protein LIN28 controls progenitor and neuronal cell fate during postnatal neurogenesis.
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Affiliation(s)
- Jennifer S Romer-Seibert
- Department of Molecular Biology, Graduate School of Biomedical Sciences, Rowan University, Stratford, New Jersey, USA; and
| | - Nathaniel W Hartman
- School of Natural Sciences and Mathematics, Stockton University, Galloway, New Jersey, USA
| | - Eric G Moss
- Department of Molecular Biology, Graduate School of Biomedical Sciences, Rowan University, Stratford, New Jersey, USA; and
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Role of mTOR Complexes in Neurogenesis. Int J Mol Sci 2018; 19:ijms19051544. [PMID: 29789464 PMCID: PMC5983636 DOI: 10.3390/ijms19051544] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/13/2018] [Accepted: 05/16/2018] [Indexed: 12/22/2022] Open
Abstract
Dysregulation of neural stem cells (NSCs) is associated with several neurodevelopmental disorders, including epilepsy and autism spectrum disorder. The mammalian target of rapamycin (mTOR) integrates the intracellular signals to control cell growth, nutrient metabolism, and protein translation. mTOR regulates many functions in the development of the brain, such as proliferation, differentiation, migration, and dendrite formation. In addition, mTOR is important in synaptic formation and plasticity. Abnormalities in mTOR activity is linked with severe deficits in nervous system development, including tumors, autism, and seizures. Dissecting the wide-ranging roles of mTOR activity during critical periods in development will greatly expand our understanding of neurogenesis.
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12
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mTOR Signaling and Neural Stem Cells: The Tuberous Sclerosis Complex Model. Int J Mol Sci 2018; 19:ijms19051474. [PMID: 29772672 PMCID: PMC5983755 DOI: 10.3390/ijms19051474] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 05/04/2018] [Accepted: 05/11/2018] [Indexed: 12/24/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR), a serine-threonine kinase, plays a pivotal role in regulating cell growth and proliferation. Notably, a great deal of evidence indicates that mTOR signaling is also crucial in controlling proliferation and differentiation of several stem cell compartments. Consequently, dysregulation of the mTOR pathway is often associated with a variety of disease, such as cancer and metabolic and genetic disorders. For instance, hyperactivation of mTORC1 in neural stem cells (NSCs) is associated with the insurgence of neurological manifestation characterizing tuberous sclerosis complex (TSC). In this review, we survey the recent contributions of TSC physiopathology studies to understand the role of mTOR signaling in both neurogenesis and tumorigenesis and discuss how these new insights can contribute to developing new therapeutic strategies for neurological diseases and cancer.
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Le Duigou C, Savary E, Morin-Brureau M, Gomez-Dominguez D, Sobczyk A, Chali F, Milior G, Kraus L, Meier JC, Kullmann DM, Mathon B, de la Prida LM, Dorfmuller G, Pallud J, Eugène E, Clemenceau S, Miles R. Imaging pathological activities of human brain tissue in organotypic culture. J Neurosci Methods 2018; 298:33-44. [PMID: 29427611 DOI: 10.1016/j.jneumeth.2018.02.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Revised: 01/27/2018] [Accepted: 02/02/2018] [Indexed: 12/17/2022]
Abstract
BACKGROUND Insights into human brain diseases may emerge from tissue obtained after operations on patients. However techniques requiring transduction of transgenes carried by viral vectors cannot be applied to acute human tissue. NEW METHOD We show that organotypic culture techniques can be used to maintain tissue from patients with three different neurological syndromes for several weeks in vitro. Optimized viral vector techniques and promoters for transgene expression are described. RESULTS Region-specific differences in neuronal form, firing pattern and organization as well as pathological activities were maintained over 40-50 days in culture. Both adeno-associated virus and lentivirus based vectors were persistently expressed from ∼10 days after application, providing 30-40 days to exploit genetically expressed constructs. Different promoters, including hSyn, e/hSyn, CMV and CaMKII, provided cell-type specific transgene expression. The Ca probe GCaMP let us explore epileptogenic synchrony and a FRET-based probe was used to follow activity of the kinase mTORC1. COMPARISON WITH EXISTING METHODS The use of a defined culture medium, with low concentrations of amino acids and no growth factors, permitted organotypic culture of tissue from humans aged 3-62 years. Epileptic activity was maintained and excitability changed relatively little until ∼6 weeks in culture. CONCLUSIONS Characteristic morphology and region-specific neuronal activities are maintained in organotypic culture of tissue from patients diagnosed with mesial temporal lobe epilepsy, cortical dysplasia and cortical glioblastoma. Viral vector techniques permit expression of probes for long-term measurements of multi-cellular activity and intra-cellular signaling.
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Affiliation(s)
- Caroline Le Duigou
- Cortex & Epilepsie, Inserm U1127, CNRS UMR7225, UPMC Univ Paris 6, Institut du Cerveau et de la Moelle épinière, Paris, 75013, France, France.
| | - Etienne Savary
- Cortex & Epilepsie, Inserm U1127, CNRS UMR7225, UPMC Univ Paris 6, Institut du Cerveau et de la Moelle épinière, Paris, 75013, France, France.
| | - Mélanie Morin-Brureau
- Cortex & Epilepsie, Inserm U1127, CNRS UMR7225, UPMC Univ Paris 6, Institut du Cerveau et de la Moelle épinière, Paris, 75013, France, France
| | - Daniel Gomez-Dominguez
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, E-28002, Spain
| | - André Sobczyk
- Cortex & Epilepsie, Inserm U1127, CNRS UMR7225, UPMC Univ Paris 6, Institut du Cerveau et de la Moelle épinière, Paris, 75013, France, France
| | - Farah Chali
- Cortex & Epilepsie, Inserm U1127, CNRS UMR7225, UPMC Univ Paris 6, Institut du Cerveau et de la Moelle épinière, Paris, 75013, France, France
| | - Giampaolo Milior
- Cortex & Epilepsie, Inserm U1127, CNRS UMR7225, UPMC Univ Paris 6, Institut du Cerveau et de la Moelle épinière, Paris, 75013, France, France
| | - Larissa Kraus
- Cell Physiology, Technische Universität Braunschweig, Braunschweig, Germany; Charite Universitätsmedizin, Clinical and Experimental Epileptology, Berlin, Germany; Berlin Institute of Health (BIH), 10178, Berlin, Germany
| | - Jochen C Meier
- Cell Physiology, Technische Universität Braunschweig, Braunschweig, Germany
| | | | - Bertrand Mathon
- Neurochirurgie, AP-HP, GH Pitie-Salpêtrière-Charles Foix, Paris, 75013, France
| | | | - Georg Dorfmuller
- Neurochirurgie, Fondation Ophtalmologique Rothschild, 75019, Paris, France
| | - Johan Pallud
- Neurochirurgie, Hôpital Sainte-Anne, Paris Descartes University, IMA-BRAIN, Inserm, U894 Centre de Psychiatrie et Neurosciences, Paris, 75014, France
| | - Emmanuel Eugène
- Inserm U839, UPMC Univ Paris 6, Institut du Fer-à-Moulin, Paris, 75005, France
| | - Stéphane Clemenceau
- Neurochirurgie, AP-HP, GH Pitie-Salpêtrière-Charles Foix, Paris, 75013, France
| | - Richard Miles
- Cortex & Epilepsie, Inserm U1127, CNRS UMR7225, UPMC Univ Paris 6, Institut du Cerveau et de la Moelle épinière, Paris, 75013, France, France.
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Baser A, Skabkin M, Martin-Villalba A. Neural Stem Cell Activation and the Role of Protein Synthesis. Brain Plast 2017; 3:27-41. [PMID: 29765858 PMCID: PMC5928545 DOI: 10.3233/bpl-160038] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Adult neural stem cells are generated at embryonic stages by entering a quiescent state that allows their retention into adulthood and thereby maintenance of life-long brain homeostasis. Thus, a tight balance between the quiescence and activation state is instrumental to meet the brain demands for a specific cell type at the correct numbers, at a given time and position. Protein synthesis is the most energy-consuming process within the cell and, not surprisingly, it occurs at low rates in quiescent stem cells. This way quiescent cells adjust to energy constraints and avoid their premature depletion. Stem cell activation is characterized by upregulation of protein synthesis followed by cell division and differentiation. The role of such upregulation as causative or rather a consequence of the activation remains elusive. Here we summarize recent findings connecting stem cell activation to the regulation of protein synthesis, particularly focusing on embryonic and adult neural stem cells of the ventricular zone.
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Affiliation(s)
- Avni Baser
- Molecular Neurobiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Maxim Skabkin
- Molecular Neurobiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Ana Martin-Villalba
- Molecular Neurobiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
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15
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Abstract
The FOXO family of transcription factors plays a conserved role in longevity and tissue homeostasis across species. In the mammalian nervous system, emerging evidence has implicated FOXOs in cognitive performance, stem cell maintenance, regeneration, and protection against stress. Much of what we know about neuronal functions of FOXO emerged from recent studies in C. elegans. Similar to mammalian FOXO, the worm FOXO ortholog, called DAF-16, regulates learning and memory, regeneration, and stress resistance in neurons. Here, we discuss the current state of our knowledge of FOXO’s functions in neurons in mammals and invertebrates, and highlight areas where our understanding is limited. Defining the function of FOXO factors in the healthy, aged, and diseased brain may have important implications for improving healthspan and treating neurodegenerative disease.
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Affiliation(s)
- Sun Y Kim
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA
| | - Ashley E Webb
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA
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