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Glutamatergic Neurons Differentiated from Embryonic Stem Cells: An Investigation of Differentiation and Associated Diseases. Int J Mol Sci 2021; 22:ijms22094592. [PMID: 33925600 PMCID: PMC8123877 DOI: 10.3390/ijms22094592] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/10/2021] [Accepted: 04/25/2021] [Indexed: 12/03/2022] Open
Abstract
Neurons that have been derived from various types of stem cells have recently undergone significant study due to their potential for use in various aspects of biomedicine. In particular, glutamatergic neurons differentiated from embryonic stem cells (ESCs) potentially have many applications in both basic research and regenerative medicine. This review summarized the literatures published thus far and focused on two areas related to these applications. Firstly, these neurons can be used to investigate neuronal signal transduction during differentiation and this means that the genes/proteins/markers involved in this process can be identified. In this way, the dynamic spatial and temporal changes associated with neuronal morphology can be investigated relatively easily. Such an in vitro system can also be used to study how neurons during neurogenesis integrate into normal tissue. At the same time, the integration, regulation and functions of extracellular matrix secretion, various molecular interactions, various ion channels, the neuronal microenvironment, etc., can be easily traced. Secondly, the disease-related aspects of ESC-derived glutamatergic neurons can also be studied and then applied therapeutically. In the future, greater efforts are needed to explore how ESC-differentiated glutamatergic neurons can be used as a neuronal model for the study of Alzheimer’s disease (AD) mechanistically, to identify possible therapeutic strategies for treating AD, including tissue replacement, and to screen for drugs that can be used to treat AD patients. With all of the modern technology that is available, translational medicine should begin to benefit patients soon.
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Carullo NVN, Phillips III RA, Simon RC, Soto SA, Hinds JE, Salisbury AJ, Revanna JS, Bunner KD, Ianov L, Sultan FA, Savell KE, Gersbach CA, Day JJ. Enhancer RNAs predict enhancer-gene regulatory links and are critical for enhancer function in neuronal systems. Nucleic Acids Res 2020; 48:9550-9570. [PMID: 32810208 PMCID: PMC7515708 DOI: 10.1093/nar/gkaa671] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/20/2020] [Accepted: 07/31/2020] [Indexed: 12/17/2022] Open
Abstract
Genomic enhancer elements regulate gene expression programs important for neuronal fate and function and are implicated in brain disease states. Enhancers undergo bidirectional transcription to generate non-coding enhancer RNAs (eRNAs). However, eRNA function remains controversial. Here, we combined Assay for Transposase-Accessible Chromatin using Sequencing (ATAC-Seq) and RNA-Seq datasets from three distinct neuronal culture systems in two activity states, enabling genome-wide enhancer identification and prediction of putative enhancer-gene pairs based on correlation of transcriptional output. Notably, stimulus-dependent enhancer transcription preceded mRNA induction, and CRISPR-based activation of eRNA synthesis increased mRNA at paired genes, functionally validating enhancer-gene predictions. Focusing on enhancers surrounding the Fos gene, we report that targeted eRNA manipulation bidirectionally modulates Fos mRNA, and that Fos eRNAs directly interact with the histone acetyltransferase domain of the enhancer-linked transcriptional co-activator CREB-binding protein (CBP). Together, these results highlight the unique role of eRNAs in neuronal gene regulation and demonstrate that eRNAs can be used to identify putative target genes.
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Affiliation(s)
- Nancy V N Carullo
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Robert A Phillips III
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Rhiana C Simon
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Salomon A Roman Soto
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jenna E Hinds
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Aaron J Salisbury
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jasmin S Revanna
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Kendra D Bunner
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Lara Ianov
- Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Faraz A Sultan
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Katherine E Savell
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Charles A Gersbach
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Jeremy J Day
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Liu Y, Zhang Y. ETV5 is Essential for Neuronal Differentiation of Human Neural Progenitor Cells by Repressing NEUROG2 Expression. Stem Cell Rev Rep 2020; 15:703-716. [PMID: 31273540 DOI: 10.1007/s12015-019-09904-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Neural progenitor cells (NPCs) are multipotent cells that have the potential to produce neurons and glial cells in the neural system. NPCs undergo identity maintenance or differentiation regulated by different kinds of transcription factors. Here we present evidence that ETV5, which is an ETS transcription factor, promotes the generation of glial cells and drives the neuronal subtype-specific genes in newly differentiated neurons from the human embryonic stem cells-derived NPCs. Next, we find a new role for ETV5 in the repression of NEUROG2 expression in NPCs. ETV5 represses NEUROG2 transcription via NEUROG2 promoter and requires the ETS domain. We identify ETV5 has the binding sites and is implicated in silent chromatin in NEUROG2 promoter by chromatin immunoprecipitation (ChIP) assays. Further, NEUROG2 transcription repression by ETV5 was shown to be dependent on a transcriptional corepressor (CoREST). During NPC differentiation toward neurons, ETV5 represses NEUROG2 expression and blocks the appearance of glutamatergic neurons. This finding suggests that ETV5 negatively regulates NEUROG2 expression and increases the number of GABAergic subtype neurons derived from NPCs. Thus, ETV5 represents a potent new candidate protein with benefits for the generation of GABAergic neurons.
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Affiliation(s)
- Yang Liu
- School of Medicine, Tongji University, No.1239, Siping Road, Shanghai, 200092, People's Republic of China.
| | - Yuanyuan Zhang
- School of Medicine, Tongji University, No.1239, Siping Road, Shanghai, 200092, People's Republic of China
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Neurogenin-2-transduced human neural progenitor cells attenuate neonatal hypoxic-ischemic brain injury. Transl Res 2017; 183:121-136.e9. [PMID: 28081931 DOI: 10.1016/j.trsl.2016.12.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Revised: 12/16/2016] [Accepted: 12/22/2016] [Indexed: 12/21/2022]
Abstract
Neonatal hypoxic-ischemic (HI) brain injury leads to high mortality and neurodevelopmental disabilities. Multipotent neural progenitor cells (NPCs) with self-renewing capacity have the potential to reduce neuronal loss and improve the compromised environment in the HI brain injury. However, the therapeutic efficacy of neuronal-committed progenitor cells and the underlying mechanisms of recovery are not yet fully understood. Therefore, this study investigated the regenerative ability and action mechanisms of neuronally committed human NPCs (hNPCs) transduced with neurogenin-2 (NEUROG2) in neonatal HI brain injury. NEUROG2- or green fluorescent protein (GFP)-encoding adenoviral vector-transduced hNPCs (NEUROG2- or GFP-NPCs) were transplanted into neonatal mouse brains with HI injury. Grafted NEUROG2-NPCs showed robust dispersion and engraftment, prolonged survival, and neuronal differentiation in HI brain injury. NEUROG2-NPCs significantly improved neurological behaviors, decreased cellular apoptosis, and increased the neurite outgrowth and axonal sprouting in HI brain injury. In contrast, GFP-NPC grafts moderately enhanced axonal extension with limited behavioral recovery. Notably, NEUROG2-NPCs showed increased secretion of multiple factors, such as nerve growth factor, brain-derived neurotrophic factor, neurotrophin-3 (NTF3), fibroblast growth factor 9 (FGF9), ciliary neurotrophic factor (CNTF), and thrombospondins 1 and 2 (THBS 1/2), which promoted SH-SY5Y neuroblastoma cell survival and neurite outgrowth. Thus, we postulate that NEUROG2-expressing human NPCs facilitate functional recovery after neonatal HI brain injury via their ability to secrete multiple factors that enhance neuronal survival and neuroplasticity.
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Rushing G, Ihrie RA. Neural stem cell heterogeneity through time and space in the ventricular-subventricular zone. FRONTIERS IN BIOLOGY 2016; 11:261-284. [PMID: 28367160 PMCID: PMC5371406 DOI: 10.1007/s11515-016-1407-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND The origin and classification of neural stem cells (NSCs) has been a subject of intense investigation for the past two decades. Efforts to categorize NSCs based on their location, function and expression have established that these cells are a heterogeneous pool in both the embryonic and adult brain. The discovery and additional characterization of adult NSCs has introduced the possibility of using these cells as a source for neuronal and glial replacement following injury or disease. To understand how one could manipulate NSC developmental programs for therapeutic use, additional work is needed to elucidate how NSCs are programmed and how signals during development are interpreted to determine cell fate. OBJECTIVE This review describes the identification, classification and characterization of NSCs within the large neurogenic niche of the ventricular-subventricular zone (V-SVZ). METHODS A literature search was conducted using Pubmed including the keywords "ventricular-subventricular zone," "neural stem cell," "heterogeneity," "identity" and/or "single cell" to find relevant manuscripts to include within the review. A special focus was placed on more recent findings using single-cell level analyses on neural stem cells within their niche(s). RESULTS This review discusses over 20 research articles detailing findings on V-SVZ NSC heterogeneity, over 25 articles describing fate determinants of NSCs, and focuses on 8 recent publications using distinct single-cell analyses of neural stem cells including flow cytometry and RNA-seq. Additionally, over 60 manuscripts highlighting the markers expressed on cells within the NSC lineage are included in a chart divided by cell type. CONCLUSIONS Investigation of NSC heterogeneity and fate decisions is ongoing. Thus far, much research has been conducted in mice however, findings in human and other mammalian species are also discussed here. Implications of NSC heterogeneity established in the embryo for the properties of NSCs in the adult brain are explored, including how these cells may be redirected after injury or genetic manipulation.
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Affiliation(s)
- Gabrielle Rushing
- Program in Neuroscience, Vanderbilt University, Nashville, TN 37232, USA
| | - Rebecca A. Ihrie
- Departments of Cancer Biology and Neurological Surgery, Vanderbilt University, Nashville, TN 37232, USA
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Li X, Tzeng SY, Liu X, Tammia M, Cheng YH, Rolfe A, Sun D, Zhang N, Green JJ, Wen X, Mao HQ. Nanoparticle-mediated transcriptional modification enhances neuronal differentiation of human neural stem cells following transplantation in rat brain. Biomaterials 2016; 84:157-166. [PMID: 26828681 DOI: 10.1016/j.biomaterials.2016.01.037] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 01/08/2016] [Accepted: 01/15/2016] [Indexed: 12/22/2022]
Abstract
Strategies to enhance survival and direct the differentiation of stem cells in vivo following transplantation in tissue repair site are critical to realizing the potential of stem cell-based therapies. Here we demonstrated an effective approach to promote neuronal differentiation and maturation of human fetal tissue-derived neural stem cells (hNSCs) in a brain lesion site of a rat traumatic brain injury model using biodegradable nanoparticle-mediated transfection method to deliver key transcriptional factor neurogenin-2 to hNSCs when transplanted with a tailored hyaluronic acid (HA) hydrogel, generating larger number of more mature neurons engrafted to the host brain tissue than non-transfected cells. The nanoparticle-mediated transcription activation method together with an HA hydrogel delivery matrix provides a translatable approach for stem cell-based regenerative therapy.
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Affiliation(s)
- Xiaowei Li
- Translational Tissue Engineering Center, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA; Department of Materials Science & Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Stephany Y Tzeng
- Translational Tissue Engineering Center, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA; Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Xiaoyan Liu
- Department of Biomedical Engineering, School of Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Markus Tammia
- Translational Tissue Engineering Center, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA; Department of Materials Science & Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Yu-Hao Cheng
- Translational Tissue Engineering Center, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
| | - Andrew Rolfe
- Department of Neurosurgery, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Dong Sun
- Department of Neurosurgery, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Ning Zhang
- Department of Biomedical Engineering, School of Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Jordan J Green
- Translational Tissue Engineering Center, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA; Department of Materials Science & Engineering, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Xuejun Wen
- Department of Chemical and Life Science Engineering, School of Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA.
| | - Hai-Quan Mao
- Translational Tissue Engineering Center, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA; Department of Materials Science & Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
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Adipose-Derived Stem Cells Expressing the Neurogenin-2 Promote Functional Recovery After Spinal Cord Injury in Rat. Cell Mol Neurobiol 2015; 36:657-67. [PMID: 26283493 DOI: 10.1007/s10571-015-0246-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 07/25/2015] [Indexed: 12/12/2022]
Abstract
Neurogenin2 (Ngn2) is a proneural gene that directs neuronal differentiation of progenitor cells during development. This study aimed to investigate whether the use of adipose-derived stem cells (ADSCs) over-expressing the Ngn2 transgene (Ngn2-ADSCs) could display the characteristics of neurogenic cells and improve functional recovery in an experimental rat model of SCI. ADSCs from rats were cultured and purified in vitro, followed by genetically modified with the Ngn2 gene. Forty-eight adult female Sprague-Dawley rats were randomly assigned to three groups: the control, ADSCs, and Ngn2-ADSCs groups. The hind-limb motor function of all rats was recorded using the Basso, Beattie, and Bresnahan locomotor rating scale for 8 weeks. Moreover, hematoxylineosin staining and immunohistochemistry were also performed. After neural induction, positive expression rate of NeuN in Ngn2-ADSCs group was upon 90 %. Following transplantation, a great number of ADSCs was found around the center of the injury spinal cord at 1 and 4 weeks, which improved retention of tissue at the lesion site. Ngn2-ADSCs differentiated into neurons, indicated by the expression of neuronal markers, NeuN and Tuj1. Additionally, transplantation of Ngn2-ADSCs upregulated the trophic factors (brain-derived neurotrophic factor and vascular endothelial growth factor), and inhibited the glial scar formation, which was indicated by immunohistochemistry with glial fibrillary acidic protein. Finally, Ngn2-ADSCs-treated animals showed the highest functional recovery among the three groups. These findings suggest that transplantation of Ngn2-overexpressed ADSCs promote the functional recovery from SCI, and improve the local microenvironment of injured cord in a more efficient way than that with ADSCs alone.
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Götz M, Sirko S, Beckers J, Irmler M. Reactive astrocytes as neural stem or progenitor cells: In vivo lineage, In vitro potential, and Genome-wide expression analysis. Glia 2015; 63:1452-68. [PMID: 25965557 PMCID: PMC5029574 DOI: 10.1002/glia.22850] [Citation(s) in RCA: 159] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 04/01/2015] [Accepted: 04/15/2015] [Indexed: 12/25/2022]
Abstract
Here, we review the stem cell hallmarks of endogenous neural stem cells (NSCs) during development and in some niches of the adult mammalian brain to then compare these with reactive astrocytes acquiring stem cell hallmarks after traumatic and ischemic brain injury. Notably, even endogenous NSCs including the earliest NSCs, the neuroepithelial cells, generate in most cases only a single type of progeny and self‐renew only for a rather short time in vivo. In vitro, however, especially cells cultured under neurosphere conditions reveal a larger potential and long‐term self‐renewal under the influence of growth factors. This is rather well comparable to reactive astrocytes in the traumatic or ischemic brain some of which acquire neurosphere‐forming capacity including multipotency and long‐term self‐renewal in vitro, while they remain within their astrocyte lineage in vivo. Both reactive astrocytes and endogenous NSCs exhibit stem cell hallmarks largely in vitro, but their lineage differs in vivo. Both populations generate largely a single cell type in vivo, but endogenous NSCs generate neurons and reactive astrocytes remain in the astrocyte lineage. However, at some early postnatal stages or in some brain regions reactive astrocytes can be released from this fate restriction, demonstrating that they can also enact neurogenesis. Thus, reactive astrocytes and NSCs share many characteristic hallmarks, but also exhibit key differences. This conclusion is further substantiated by genome‐wide expression analysis comparing NSCs at different stages with astrocytes from the intact and injured brain parenchyma. GLIA 2015;63:1452–1468
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Affiliation(s)
- Magdalena Götz
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians-University Munich, Munich, Germany.,Institute of Stem Cell Research, Helmholtz Center Munich, Munich, Germany.,SYNERGY, Excellence Cluster of Systemic Neurology, LMU, Munich, Germany
| | - Swetlana Sirko
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians-University Munich, Munich, Germany.,Institute of Stem Cell Research, Helmholtz Center Munich, Munich, Germany
| | - Johannes Beckers
- Institute of Experimental Genetics, Helmholtz Center Munich, Munich, Germany.,Department of Experimental Genetics, Technical University Munich, Freising-Weihenstephan, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Martin Irmler
- Institute of Experimental Genetics, Helmholtz Center Munich, Munich, Germany
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Dai X, Lu X, Cheng F, Hao H, Qian T, Yu W, Tang L, Li L. Neurogenin 2 enhances the neuronal differentiation of skin-derived precursors. Int J Neurosci 2014; 125:367-74. [DOI: 10.3109/00207454.2014.935375] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Obernier K, Tong CK, Alvarez-Buylla A. Restricted nature of adult neural stem cells: re-evaluation of their potential for brain repair. Front Neurosci 2014; 8:162. [PMID: 24987325 PMCID: PMC4060730 DOI: 10.3389/fnins.2014.00162] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 05/28/2014] [Indexed: 01/17/2023] Open
Abstract
Neural stem cells (NSCs) in the walls of the lateral ventricles continue to produce new neurons and oligodendrocytes throughout life. The identification of NSCs, long-range neuronal migration, and the integration of new neurons into fully formed mature neural circuits-all in the juvenile or adult brain-has dramatically changed concepts in neurodevelopment and suggests new strategies for brain repair. Yet, the latter has to be seen in perspective: NSCs in the adult are heterogeneous and highly regionally specified; young neurons derived from these primary progenitors migrate and integrate in specific brain regions. Neurogenesis appears to have a function in brain plasticity rather than brain repair. If similar processes could be induced in regions of the brain that are normally not a target of new neurons, therapeutic neuronal replacement may one day reinstate neural circuit plasticity and possibly repair broken neural circuits.
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Affiliation(s)
- Kirsten Obernier
- Department of Neurological Surgery, The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco San Francisco, CA, USA
| | - Cheuk Ka Tong
- Department of Neurological Surgery, The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco San Francisco, CA, USA
| | - Arturo Alvarez-Buylla
- Department of Neurological Surgery, The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco San Francisco, CA, USA
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RAS/ERK signaling controls proneural genetic programs in cortical development and gliomagenesis. J Neurosci 2014; 34:2169-90. [PMID: 24501358 DOI: 10.1523/jneurosci.4077-13.2014] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Neural cell fate specification is well understood in the embryonic cerebral cortex, where the proneural genes Neurog2 and Ascl1 are key cell fate determinants. What is less well understood is how cellular diversity is generated in brain tumors. Gliomas and glioneuronal tumors, which are often localized in the cerebrum, are both characterized by a neoplastic glial component, but glioneuronal tumors also have an intermixed neuronal component. A core abnormality in both tumor groups is overactive RAS/ERK signaling, a pro-proliferative signal whose contributions to cell differentiation in oncogenesis are largely unexplored. We found that RAS/ERK activation levels differ in two distinct human tumors associated with constitutively active BRAF. Pilocytic astrocytomas, which contain abnormal glial cells, have higher ERK activation levels than gangliogliomas, which contain abnormal neuronal and glial cells. Using in vivo gain of function and loss of function in the mouse embryonic neocortex, we found that RAS/ERK signals control a proneural genetic switch, inhibiting Neurog2 expression while inducing Ascl1, a competing lineage determinant. Furthermore, we found that RAS/ERK levels control Ascl1's fate specification properties in murine cortical progenitors--at higher RAS/ERK levels, Ascl1(+) progenitors are biased toward proliferative glial programs, initiating astrocytomas, while at moderate RAS/ERK levels, Ascl1 promotes GABAergic neuronal and less glial differentiation, generating glioneuronal tumors. Mechanistically, Ascl1 is phosphorylated by ERK, and ERK phosphoacceptor sites are necessary for Ascl1's GABAergic neuronal and gliogenic potential. RAS/ERK signaling thus acts as a rheostat to influence neural cell fate selection in both normal cortical development and gliomagenesis, controlling Neurog2-Ascl1 expression and Ascl1 function.
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Leone L, Fusco S, Mastrodonato A, Piacentini R, Barbati SA, Zaffina S, Pani G, Podda MV, Grassi C. Epigenetic Modulation of Adult Hippocampal Neurogenesis by Extremely Low-Frequency Electromagnetic Fields. Mol Neurobiol 2014; 49:1472-86. [DOI: 10.1007/s12035-014-8650-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 01/22/2014] [Indexed: 12/22/2022]
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Targeted delivery of neurogenin-2 protein in the treatment for cerebral ischemia-reperfusion injury. Biomaterials 2013; 34:8786-97. [PMID: 23942209 DOI: 10.1016/j.biomaterials.2013.07.076] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 07/21/2013] [Indexed: 12/28/2022]
Abstract
Neurogenin-2 (Ngn2), as a proneural gene that promotes the survival and differentiation of neural precursor cells, is an attractive candidate for therapy against cerebral ischemia-reperfusion injury. However, the delivery approach limits its clinical application. To deliver Ngn2 protein into the cerebral ischemic region and exert a therapeutic effect on injured neurons after ischemia, we here reported that the fusion protein TAT-LBD-Ngn2 was constructed by fusing a transactivator of transcription (TAT) domain and a laminin-binding domain (LBD) to Ngn2. TAT-LBD-Ngn2 promoted the outgrowth of neuronal neurite, increased the survival rate and alleviated apoptosis of hippocampal neurons exposed to oxygen glucose deprivation in vitro. Furthermore, a focal cerebral ischemia model in C57BL/6 mice showed that TAT-LBD-Ngn2 efficiently crossed the blood brain barrier, aggregated in the ischemic zone and was consistently incorporated into neurons. Moreover, TAT-LBD-Ngn2 transduced into brains attenuated neuronal degeneration and apoptosis in the ischemic zone. TAT-LBD-Ngn2 treatment resulted in a reduction of infarct volume that was associated with a parallel improvement in neurological functional outcomes after reperfusion. In conclusion, the targeted delivery of TAT-LBD-Ngn2 into the ischemic zone attenuated cerebral ischemia-reperfusion injury through the inhibition of neuronal degeneration and apoptosis, suggesting that TAT-LBD-Ngn2 is a promising target candidate for the treatment of ischemic stroke.
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