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Islam R, Noman H, Azimi A, Siu R, Chinchalongporn V, Schuurmans C, Morshead CM. Primitive and Definitive Neural Precursor Cells Are Present in Human Cerebral Organoids. Int J Mol Sci 2024; 25:6549. [PMID: 38928255 PMCID: PMC11203442 DOI: 10.3390/ijms25126549] [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] [Received: 05/01/2024] [Revised: 06/04/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024] Open
Abstract
Activation of neural stem cells (NSCs) correlates with improved functional outcomes in mouse models of injury. In the murine brain, NSCs have been extensively characterized and comprise (1) primitive NSCs (pNSCs) and (2) definitive NSCs (dNSCs). pNSCs are the earliest cells in the NSC lineage giving rise to dNSCs in the embryonic and adult mouse brain. pNSCs are quiescent under baseline conditions and can be activated upon injury. Herein, we asked whether human pNSCs and dNSCs can be isolated during the maturation of human cerebral organoids (COs) and activated by drugs known to regulate mouse NSC behavior. We demonstrate that self-renewing, multipotent pNSC and dNSC populations are present in human COs and express genes previously characterized in mouse NSCs. The drug NWL283, an inhibitor of apoptosis, reduced cell death in COs but did not improve NSC survival. Metformin, a drug used to treat type II diabetes that is known to promote NSC activation in mice, was found to expand human NSC pools. Together, these findings are the first to identify and characterize human pNSCs, advancing our understanding of the human NSC lineage and highlighting drugs that enhance their activity.
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Affiliation(s)
- Rehnuma Islam
- Institute of Medical Science, University of Toronto, 1 King’s College Circle, Toronto, ON M5S 3E1, Canada
| | - Humna Noman
- Institute of Medical Science, University of Toronto, 1 King’s College Circle, Toronto, ON M5S 3E1, Canada
| | - Ashkan Azimi
- Department of Surgery, University of Toronto, 149 College Street, Toronto, ON M5T 1P5, Canada
| | - Ricky Siu
- Department of Surgery, University of Toronto, 149 College Street, Toronto, ON M5T 1P5, Canada
| | | | - Carol Schuurmans
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada
- Department of Biochemistry, University of Toronto, 1 King’s College Circle, Toronto, ON M5S 3E1, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King’s College Circle, Toronto, ON M5S 3E1, Canada
| | - Cindi M. Morshead
- Institute of Medical Science, University of Toronto, 1 King’s College Circle, Toronto, ON M5S 3E1, Canada
- Department of Surgery, University of Toronto, 149 College Street, Toronto, ON M5T 1P5, Canada
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9, Canada
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Yammine SZ, Burns I, Gosio J, Peluso A, Merritt DM, Innes B, Coles BLK, Yan WR, Bader GD, Morshead CM, van der Kooy D. Fate Specification of GFAP-Negative Primitive Neural Stem Cells and Their Progeny at Clonal Resolution. Stem Cells Dev 2023; 32:606-621. [PMID: 37551982 DOI: 10.1089/scd.2023.0038] [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: 08/09/2023] Open
Abstract
The mature brain contains an incredible number and diversity of cells that are produced and maintained by heterogeneous pools of neural stem cells (NSCs). Two distinct types of NSCs exist in the developing and adult mouse brain: Glial Fibrillary Acidic Protein (GFAP)-negative primitive (p)NSCs and downstream GFAP-positive definitive (d)NSCs. To better understand the embryonic functions of NSCs, we performed clonal lineage tracing within neurospheres grown from either pNSCs or dNSCs to enrich for their most immediate downstream neural progenitor cells (NPCs). These clonal progenitor lineage tracing data allowed us to construct a hierarchy of progenitor subtypes downstream of pNSCs and dNSCs that were then validated using single-cell transcriptomics. Further, we identify Nexn as required for neuronal specification from neuron/astrocyte progenitor cells downstream of rare pNSCs. Combined, these data provide single-cell resolution of NPC lineages downstream of rare pNSCs that likely would be missed from population-level analyses in vivo.
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Affiliation(s)
- Samantha Z Yammine
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Ian Burns
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Jessica Gosio
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
- Center for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
| | - Andrew Peluso
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Daniel M Merritt
- Institute of Medical Science, University of Toronto, Toronto, Canada
| | - Brendan Innes
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Brenda L K Coles
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Wen Rui Yan
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Gary D Bader
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
- The Donnelly Centre and University of Toronto, Toronto, Canada
| | - Cindi M Morshead
- The Donnelly Centre and University of Toronto, Toronto, Canada
- Department of Surgery, University of Toronto, Toronto, Canada
| | - Derek van der Kooy
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
- The Donnelly Centre and University of Toronto, Toronto, Canada
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Regulating Endogenous Neural Stem Cell Activation to Promote Spinal Cord Injury Repair. Cells 2022; 11:cells11050846. [PMID: 35269466 PMCID: PMC8909806 DOI: 10.3390/cells11050846] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 02/24/2022] [Accepted: 02/25/2022] [Indexed: 12/12/2022] Open
Abstract
Spinal cord injury (SCI) affects millions of individuals worldwide. Currently, there is no cure, and treatment options to promote neural recovery are limited. An innovative approach to improve outcomes following SCI involves the recruitment of endogenous populations of neural stem cells (NSCs). NSCs can be isolated from the neuroaxis of the central nervous system (CNS), with brain and spinal cord populations sharing common characteristics (as well as regionally distinct phenotypes). Within the spinal cord, a number of NSC sub-populations have been identified which display unique protein expression profiles and proliferation kinetics. Collectively, the potential for NSCs to impact regenerative medicine strategies hinges on their cardinal properties, including self-renewal and multipotency (the ability to generate de novo neurons, astrocytes, and oligodendrocytes). Accordingly, endogenous NSCs could be harnessed to replace lost cells and promote structural repair following SCI. While studies exploring the efficacy of this approach continue to suggest its potential, many questions remain including those related to heterogeneity within the NSC pool, the interaction of NSCs with their environment, and the identification of factors that can enhance their response. We discuss the current state of knowledge regarding populations of endogenous spinal cord NSCs, their niche, and the factors that regulate their behavior. In an attempt to move towards the goal of enhancing neural repair, we highlight approaches that promote NSC activation following injury including the modulation of the microenvironment and parenchymal cells, pharmaceuticals, and applied electrical stimulation.
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Grisé KN, Coles BLK, Bautista NX, van der Kooy D. Activation of adult mammalian retinal stem cells in vivo via antagonism of BMP and sFRP2. Stem Cell Res Ther 2021; 12:560. [PMID: 34717744 PMCID: PMC8557620 DOI: 10.1186/s13287-021-02630-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/17/2021] [Indexed: 11/15/2022] Open
Abstract
Background The adult mammalian retina does not have the capacity to regenerate cells lost due to damage or disease. Therefore, retinal injuries and blinding diseases result in irreversible vision loss. However, retinal stem cells (RSCs), which participate in retinogenesis during development, persist in a quiescent state in the ciliary epithelium (CE) of the adult mammalian eye. Moreover, RSCs retain the ability to generate all retinal cell types when cultured in vitro, including photoreceptors. Therefore, it may be possible to activate endogenous RSCs to induce retinal neurogenesis in vivo and restore vision in the adult mammalian eye. Methods To investigate if endogenous RSCs can be activated, we performed combinatorial intravitreal injections of antagonists to BMP and sFRP2 proteins (two proposed mediators of RSC quiescence in vivo), with or without growth factors FGF and Insulin. We also investigated the effects of chemically-induced N-methyl-N-Nitrosourea (MNU) retinal degeneration on RSC activation, both alone and in combination withthe injected factors. Further, we employed inducible Msx1-CreERT2 genetic lineage labeling of the CE followed by stimulation paradigms to determine if activated endogenous RSCs could migrate into the retina and differentiate into retinal neurons. Results We found that in vivo antagonism of BMP and sFRP2 proteins induced CE cells in the RSC niche to proliferate and expanded the RSC population. BMP and sFRP2 antagonism also enhanced CE cell proliferation in response to exogenous growth factor stimulation and MNU-induced retinal degeneration. Furthermore, Msx1-CreERT2 genetic lineage tracing revealed that CE cells migrated into the retina following stimulation and/or injury, where they expressed markers of mature photoreceptors and retinal ganglion cells. Conclusions Together, these results indicate that endogenous adult mammalian RSCs may have latent regenerative potential that can be activated by modulating the RSC niche and hold promise as a means for endogenous retinal cell therapy to repair the retina and improve vision. Supplementary Information The online version contains supplementary material available at 10.1186/s13287-021-02630-0.
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Affiliation(s)
- Kenneth N Grisé
- Department of Molecular Genetics, University of Toronto, Donnelly Centre Rm 1110, 160 College Street, Toronto, ON, M5S 3E1, Canada.
| | - Brenda L K Coles
- Department of Molecular Genetics, University of Toronto, Donnelly Centre Rm 1110, 160 College Street, Toronto, ON, M5S 3E1, Canada
| | - Nelson X Bautista
- Department of Molecular Genetics, University of Toronto, Donnelly Centre Rm 1110, 160 College Street, Toronto, ON, M5S 3E1, Canada
| | - Derek van der Kooy
- Department of Molecular Genetics, University of Toronto, Donnelly Centre Rm 1110, 160 College Street, Toronto, ON, M5S 3E1, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, M5S 1A8, Canada
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Grisé KN, Bautista NX, Jacques K, Coles BLK, van der Kooy D. Glucocorticoid agonists enhance retinal stem cell self-renewal and proliferation. Stem Cell Res Ther 2021; 12:83. [PMID: 33494791 PMCID: PMC7831262 DOI: 10.1186/s13287-021-02136-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 01/01/2021] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Adult mammalian retinal stem cells (RSCs) readily proliferate, self-renew, and generate progeny that differentiate into all retinal cell types in vitro. RSC-derived progeny can be induced to differentiate into photoreceptors, making them a potential source for retinal cell transplant therapies. Despite their proliferative propensity in vitro, RSCs in the adult mammalian eye do not proliferate and do not have a regenerative response to injury. Thus, identifying and modulating the mechanisms that regulate RSC proliferation may enhance the capacity to produce RSC-derived progeny in vitro and enable RSC activation in vivo. METHODS Here, we used medium-throughput screening to identify small molecules that can expand the number of RSCs and their progeny in culture. In vitro differentiation assays were used to assess the effects of synthetic glucocorticoid agonist dexamethasone on RSC-derived progenitor cell fate. Intravitreal injections of dexamethasone into adult mouse eyes were used to investigate the effects on endogenous RSCs. RESULTS We discovered that high-affinity synthetic glucocorticoid agonists increase RSC self-renewal and increase retinal progenitor proliferation up to 6-fold without influencing their differentiation in vitro. Intravitreal injection of synthetic glucocorticoid agonist dexamethasone induced in vivo proliferation in the ciliary epithelium-the niche in which adult RSCs reside. CONCLUSIONS Together, our results identify glucocorticoids as novel regulators of retinal stem and progenitor cell proliferation in culture and provide evidence that GCs may activate endogenous RSCs.
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Affiliation(s)
- Kenneth N Grisé
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada.
| | - Nelson X Bautista
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Krystal Jacques
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Brenda L K Coles
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Derek van der Kooy
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, M5S 1A8, Canada
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Ahuja CS, Mothe A, Khazaei M, Badhiwala JH, Gilbert EA, van der Kooy D, Morshead CM, Tator C, Fehlings MG. The leading edge: Emerging neuroprotective and neuroregenerative cell-based therapies for spinal cord injury. Stem Cells Transl Med 2020; 9:1509-1530. [PMID: 32691994 PMCID: PMC7695641 DOI: 10.1002/sctm.19-0135] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 06/01/2020] [Accepted: 06/23/2020] [Indexed: 12/12/2022] Open
Abstract
Spinal cord injuries (SCIs) are associated with tremendous physical, social, and financial costs for millions of individuals and families worldwide. Rapid delivery of specialized medical and surgical care has reduced mortality; however, long-term functional recovery remains limited. Cell-based therapies represent an exciting neuroprotective and neuroregenerative strategy for SCI. This article summarizes the most promising preclinical and clinical cell approaches to date including transplantation of mesenchymal stem cells, neural stem cells, oligodendrocyte progenitor cells, Schwann cells, and olfactory ensheathing cells, as well as strategies to activate endogenous multipotent cell pools. Throughout, we emphasize the fundamental biology of cell-based therapies, critical features in the pathophysiology of spinal cord injury, and the strengths and limitations of each approach. We also highlight salient completed and ongoing clinical trials worldwide and the bidirectional translation of their findings. We then provide an overview of key adjunct strategies such as trophic factor support to optimize graft survival and differentiation, engineered biomaterials to provide a support scaffold, electrical fields to stimulate migration, and novel approaches to degrade the glial scar. We also discuss important considerations when initiating a clinical trial for a cell therapy such as the logistics of clinical-grade cell line scale-up, cell storage and transportation, and the delivery of cells into humans. We conclude with an outlook on the future of cell-based treatments for SCI and opportunities for interdisciplinary collaboration in the field.
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Affiliation(s)
- Christopher S. Ahuja
- Division of Neurosurgery, Department of SurgeryUniversity of TorontoTorontoOntarioCanada
- Institute of Medical ScienceUniversity of TorontoTorontoOntarioCanada
- Department of Genetics and DevelopmentKrembil Research Institute, UHNTorontoOntarioCanada
| | - Andrea Mothe
- Department of Genetics and DevelopmentKrembil Research Institute, UHNTorontoOntarioCanada
| | - Mohamad Khazaei
- Department of Genetics and DevelopmentKrembil Research Institute, UHNTorontoOntarioCanada
| | - Jetan H. Badhiwala
- Division of Neurosurgery, Department of SurgeryUniversity of TorontoTorontoOntarioCanada
| | - Emily A. Gilbert
- Division of Anatomy, Department of SurgeryUniversity of TorontoTorontoOntarioCanada
| | - Derek van der Kooy
- Department of Molecular GeneticsUniversity of TorontoTorontoOntarioCanada
| | - Cindi M. Morshead
- Institute of Medical ScienceUniversity of TorontoTorontoOntarioCanada
- Division of Anatomy, Department of SurgeryUniversity of TorontoTorontoOntarioCanada
- Institute of Biomaterials and Biomedical EngineeringUniversity of TorontoTorontoOntarioCanada
| | - Charles Tator
- Division of Neurosurgery, Department of SurgeryUniversity of TorontoTorontoOntarioCanada
- Institute of Medical ScienceUniversity of TorontoTorontoOntarioCanada
- Department of Genetics and DevelopmentKrembil Research Institute, UHNTorontoOntarioCanada
| | - Michael G. Fehlings
- Division of Neurosurgery, Department of SurgeryUniversity of TorontoTorontoOntarioCanada
- Institute of Medical ScienceUniversity of TorontoTorontoOntarioCanada
- Department of Genetics and DevelopmentKrembil Research Institute, UHNTorontoOntarioCanada
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Vadhan JD, Speth RC. The role of the brain renin-angiotensin system (RAS) in mild traumatic brain injury (TBI). Pharmacol Ther 2020; 218:107684. [PMID: 32956721 DOI: 10.1016/j.pharmthera.2020.107684] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2020] [Indexed: 02/07/2023]
Abstract
There is considerable interest in traumatic brain injury (TBI) induced by repeated concussions suffered by athletes in sports, military personnel from combat-and non-combat related activities, and civilian populations who suffer head injuries from accidents and domestic violence. Although the renin-angiotensin system (RAS) is primarily a systemic cardiovascular regulatory system that, when dysregulated, causes hypertension and cardiovascular pathology, the brain contains a local RAS that plays a critical role in the pathophysiology of several neurodegenerative diseases. This local RAS includes receptors for angiotensin (Ang) II within the brain parenchyma, as well as on circumventricular organs outside the blood-brain-barrier. The brain RAS acts primarily via the type 1 Ang II receptor (AT1R), exacerbating insults and pathology. With TBI, the brain RAS may contribute to permanent brain damage, especially when a second TBI occurs before the brain recovers from an initial injury. Agents are needed that minimize the extent of injury from an acute TBI, reducing TBI-mediated permanent brain damage. This review discusses how activation of the brain RAS following TBI contributes to this damage, and how drugs that counteract activation of the AT1R including AT1R blockers (ARBs), renin inhibitors, angiotensin-converting enzyme (ACE) inhibitors, and agonists at type 2 Ang II receptors (AT2) and at Ang (1-7) receptors (Mas) can potentially ameliorate TBI-induced brain damage.
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Affiliation(s)
- Jason D Vadhan
- College of Osteopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL, United States of America
| | - Robert C Speth
- Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Fort Lauderdale, FL, United States of America; School of Medicine, Georgetown University, Washington, DC, United States of America.
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Lineage tracing reveals the hierarchical relationship between neural stem cell populations in the mouse forebrain. Sci Rep 2019; 9:17730. [PMID: 31776378 PMCID: PMC6881290 DOI: 10.1038/s41598-019-54143-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 11/04/2019] [Indexed: 11/25/2022] Open
Abstract
Since the original isolation of neural stem cells (NSCs) in the adult mammalian brain, further work has revealed a heterogeneity in the NSC pool. Our previous work characterized a distinct, Oct4 expressing, NSC population in the periventricular region, through development and into adulthood. We hypothesized that this population is upstream in lineage to the more abundant, well documented, GFAP expressing NSC. Herein, we show that Oct4 expressing NSCs give rise to neurons, astrocytes and oligodendrocytes throughout the developing brain. Further, transgenic inducible mouse models demonstrate that the rare Oct4 expressing NSCs undergo asymmetric divisions to give rise to GFAP expressing NSCs in naïve and injured brains. This lineage relationship between distinct NSC pools contributes significantly to an understanding of neural development, the NSC lineage in vivo and has implications for neural repair.
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Investigating Nrg1 Signaling in the Regenerating Axolotl Spinal Cord Using Multiplexed FISH. Dev Neurobiol 2019; 79:453-467. [DOI: 10.1002/dneu.22670] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 01/24/2019] [Accepted: 02/16/2019] [Indexed: 02/02/2023]
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Abstract
KIT is a receptor tyrosine kinase that after binding to its ligand stem cell factor activates signaling cascades linked to biological processes such as proliferation, differentiation, migration and cell survival. Based on studies performed on SCF and/or KIT mutant animals that presented anemia, sterility, and/or pigmentation disorders, KIT signaling was mainly considered to be involved in the regulation of hematopoiesis, gametogenesis, and melanogenesis. More recently, novel animal models and ameliorated cellular and molecular techniques have led to the discovery of a widen repertoire of tissue compartments and functions that are being modulated by KIT. This is the case for the lung, heart, nervous system, gastrointestinal tract, pancreas, kidney, liver, and bone. For this reason, the tyrosine kinase inhibitors that were originally developed for the treatment of hemato-oncological diseases are being currently investigated for the treatment of non-oncological disorders such as asthma, rheumatoid arthritis, and alzheimer's disease, among others. The beneficial effects of some of these tyrosine kinase inhibitors have been proven to depend on KIT inhibition. This review will focus on KIT expression and regulation in healthy and pathologic conditions other than cancer. Moreover, advances in the development of anti-KIT therapies, including tyrosine kinase inhibitors, and their application will be discussed.
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Adams KV, Morshead CM. Neural stem cell heterogeneity in the mammalian forebrain. Prog Neurobiol 2018; 170:2-36. [PMID: 29902499 DOI: 10.1016/j.pneurobio.2018.06.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 05/23/2018] [Accepted: 06/07/2018] [Indexed: 12/21/2022]
Abstract
The brain was long considered an organ that underwent very little change after development. It is now well established that the mammalian central nervous system contains neural stem cells that generate progeny that are capable of making new neurons, astrocytes, and oligodendrocytes throughout life. The field has advanced rapidly as it strives to understand the basic biology of these precursor cells, and explore their potential to promote brain repair. The purpose of this review is to present current knowledge about the diversity of neural stem cells in vitro and in vivo, and highlight distinctions between neural stem cell populations, throughout development, and within the niche. A comprehensive understanding of neural stem cell heterogeneity will provide insights into the cellular and molecular regulation of neural development and lifelong neurogenesis, and will guide the development of novel strategies to promote regeneration and neural repair.
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Affiliation(s)
- Kelsey V Adams
- Institute of Medical Science, Terrence Donnelly Centre, University of Toronto, Toronto ON, M5S 3E2, Canada.
| | - Cindi M Morshead
- Institute of Medical Science, Terrence Donnelly Centre, University of Toronto, Toronto ON, M5S 3E2, Canada; Department of Surgery, Division of Anatomy, Canada; Institute of Biomaterials and Biomedical Engineering, Canada; Rehabilitation Science Institute, University of Toronto, Canada.
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12
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Home sweet home: the neural stem cell niche throughout development and after injury. Cell Tissue Res 2017; 371:125-141. [PMID: 28776186 DOI: 10.1007/s00441-017-2658-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 05/29/2017] [Indexed: 12/26/2022]
Abstract
Neural stem cells and their progeny reside in two distinct neurogenic niches within the mammalian brain: the subventricular zone and the dentate gyrus. The interplay between the neural stem cells and the niche in which they reside can have significant effects on cell kinetics and neurogenesis. A comprehensive understanding of the changes to the niche that occur through postnatal development and aging, as well as following injury, is relevant for developing therapeutics and interventions to promote neural repair. We discuss changes that occur within the neural stem and progenitor cell populations, the vasculature, extracellular matrix, microglia, and secreted proteins through aging which impact cell behavior within the neurogenic niches. We examine neural precursor cell and niche responses to injury in neonatal hypoxia-ischemia, juvenile cranial irradiation, and adult stroke. This review examines the interplay between the niche and stem cell behavior through aging and following injury as a means to understand intrinsic and extrinsic factors that regulate neurogenesis in vivo.
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Reeve RL, Yammine SZ, Morshead CM, van der Kooy D. Quiescent Oct4 + Neural Stem Cells (NSCs) Repopulate Ablated Glial Fibrillary Acidic Protein + NSCs in the Adult Mouse Brain. Stem Cells 2017; 35:2071-2082. [PMID: 28733998 DOI: 10.1002/stem.2662] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 05/19/2017] [Accepted: 06/13/2017] [Indexed: 11/12/2022]
Abstract
Adult primitive neural stem cells (pNSCs) are a rare population of glial fibrillary acidic protein (GFAP)- Oct4+ cells in the mouse forebrain subependymal zone bordering the lateral ventricles that give rise to clonal neurospheres in leukemia inhibitory factor in vitro. pNSC neurospheres can be passaged to self-renew or give rise to GFAP+ NSCs that form neurospheres in epidermal growth factor and fibroblast growth factor 2, which we collectively refer to as definitive NSCs (dNSCs). Label retention experiments using doxycycline-inducible histone-2B (H2B)-green fluorescent protein (GFP) mice and several chase periods of up to 1 year quantified the adult pNSC cell cycle time as 3-5 months. We hypothesized that while pNSCs are not very proliferative at baseline, they may exist as a reserve pool of NSCs in case of injury. To test this function of pNSCs, we obtained conditional Oct4 knockout mice, Oct4fl/fl ;Sox1Cre (Oct4CKO ), which do not yield adult pNSC-derived neurospheres. When we ablated the progeny of pNSCs, namely all GFAP+ dNSCs, in these Oct4CKO mice, we found that dNSCs did not recover as they do in wild-type mice, suggesting that pNSCs are necessary for dNSC repopulation. Returning to the H2B-GFP mice, we observed that the cytosine β-d-arabinofuranoside ablation of proliferating cells including dNSCs-induced quiescent pNSCs to proliferate and significantly dilute their H2B-GFP label. In conclusion, we demonstrate that pNSCs are the most quiescent stem cells in the adult brain reported to date and that their lineage position upstream of GFAP+ dNSCs allows them to repopulate a depleted neural lineage. Stem Cells 2017;35:2071-2082.
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Affiliation(s)
- Rachel L Reeve
- Institute of Medical Sciences, University of Toronto, Toronto, Canada
| | - Samantha Z Yammine
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | | | - Derek van der Kooy
- Institute of Medical Sciences, University of Toronto, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
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14
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Xu W, Lakshman N, Morshead CM. Building a central nervous system: The neural stem cell lineage revealed. NEUROGENESIS 2017; 4:e1300037. [PMID: 28516107 PMCID: PMC5424705 DOI: 10.1080/23262133.2017.1300037] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 02/20/2017] [Accepted: 02/21/2017] [Indexed: 01/25/2023]
Abstract
Neural stem cells (NSCs) are a multipotent, self-renewing source of undifferentiated cells in the periventricular region of the mammalian central nervous system (CNS). Since their original discovery 25 years ago, much has been learned about their development, persistence, localization, properties and potential. Herein we discuss the current state of knowledge pertaining to neural stem cells with a focus on the lineage relationship between two NSC populations along the neuraxis and their regionally distinct niches in the CNS.
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Affiliation(s)
- Wenjun Xu
- Department of Surgery, Division of Anatomy, Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Nishanth Lakshman
- Department of Surgery, Division of Anatomy, Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Cindi M Morshead
- Department of Surgery, Division of Anatomy, Institute of Medical Science, University of Toronto, Toronto, ON, Canada
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