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Chen J, Huang L, Yang Y, Xu W, Qin Q, Qin R, Liang X, Lai X, Huang X, Xie M, Chen L. Somatic Cell Reprogramming for Nervous System Diseases: Techniques, Mechanisms, Potential Applications, and Challenges. Brain Sci 2023; 13:brainsci13030524. [PMID: 36979334 PMCID: PMC10046178 DOI: 10.3390/brainsci13030524] [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: 02/04/2023] [Revised: 03/14/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Nervous system diseases present significant challenges to the neuroscience community due to ethical and practical constraints that limit access to appropriate research materials. Somatic cell reprogramming has been proposed as a novel way to obtain neurons. Various emerging techniques have been used to reprogram mature and differentiated cells into neurons. This review provides an overview of somatic cell reprogramming for neurological research and therapy, focusing on neural reprogramming and generating different neural cell types. We examine the mechanisms involved in reprogramming and the challenges that arise. We herein summarize cell reprogramming strategies to generate neurons, including transcription factors, small molecules, and microRNAs, with a focus on different types of cells.. While reprogramming somatic cells into neurons holds the potential for understanding neurological diseases and developing therapeutic applications, its limitations and risks must be carefully considered. Here, we highlight the potential benefits of somatic cell reprogramming for neurological disease research and therapy. This review contributes to the field by providing a comprehensive overview of the various techniques used to generate neurons by cellular reprogramming and discussing their potential applications.
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Affiliation(s)
- Jiafeng Chen
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Lijuan Huang
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Yue Yang
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Wei Xu
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Qingchun Qin
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Rongxing Qin
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Xiaojun Liang
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Xinyu Lai
- Key Laboratory of Longevity and Aging-Related Diseases of Chinese Ministry of Education, Nanning 530021, China
| | - Xiaoying Huang
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Minshan Xie
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Li Chen
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
- Key Laboratory of Longevity and Aging-Related Diseases of Chinese Ministry of Education, Nanning 530021, China
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2
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Feng B, Jia S, Li L, Wang J, Zhou F, Gou X, Wang Q, Xiong L, Zeng Y, Zhong H. TAT-LBD-Ngn2-improved cognitive functions after global cerebral ischemia by enhancing neurogenesis. Brain Behav 2023; 13:e2847. [PMID: 36495119 PMCID: PMC9847610 DOI: 10.1002/brb3.2847] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 10/21/2022] [Accepted: 11/23/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Stroke is the major cause of adult neurocognitive disorders (NCDs), and presents a significant burden on both of the families and society. To improve the cerebral injury, we generated a blood-brain barrier penetrating peptide TAT-LBD-Ngn2, in which Ngn2 (Neurogenin2) is a classical preneural gene that enhances neurogenesis, and neural precursor cells survival and differentiation. We previously demonstrated that it has a short-term protective effect against cerebral ischemia-reperfusion injury. However, it is uncertain if TAT-LBD-Ngn2 could promote neurogenesis to exhibit long-term therapeutic impact. METHODS AND RESULTS In present study, TAT-LBD-Ngn2 was administered for 14 or 28 days following bilateral common carotid arteries occlusion (BCCAO). After confirming that TAT-LBD-Ngn2 could cross the brain blood barrier and aggregate in the hippocampus, we conducted open field test, Morris water maze and contextual fear conditioning to examine the long-term effect of TAT-LBD-Ngn2 on cognition. We discovered that TAT-LBD-Ngn2 significantly improved the spatial and contextual learning and memory on both days 14 and 28 after BCCAO, while TAT-LBD-Ngn2 exhibited anxiolytic effect only on day 14, but had no effect on locomotion. Using western blot and immunofluorescence, TAT-LBD-Ngn2 was also shown to promote neurogenesis, as evidenced by increased BrdU+ and DCX+ neurons in dentate gyrus. Meanwhile, TAT-LBD-Ngn2 elevated the expression of brain derived neurotrophic factor rather than nerve growth factor compared to the control group. CONCLUSIONS Our findings revealed that TAT-LBD-Ngn2 could dramatically promote learning and memory in long term by facilitating neurogenesis in the hippocampus after global cerebral ischemia, indicating that TAT-LBD-Ngn2 may be an appealing candidate for treating poststroke NCD.
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Affiliation(s)
- Bin Feng
- Department of Radiation Oncology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Sansan Jia
- Department of Anesthesiology and perioperative medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Liya Li
- Department of Anesthesiology and perioperative medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China.,Department of Anesthesiology, The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Jiajia Wang
- Department of Anesthesiology and perioperative medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Fang Zhou
- Department of Anesthesiology and perioperative medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xingchun Gou
- Shaanxi Key Laboratory of Brain Disorders & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, China
| | - Qiang Wang
- Department of Anesthesiology and perioperative medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China.,Department of Anesthesiology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Lize Xiong
- Department of Anesthesiology and perioperative medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China.,Department of Anesthesiology and Perioperative Medicine, Shanghai Fourth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yi Zeng
- Department of Anesthesiology and perioperative medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Haixing Zhong
- Department of Anesthesiology and perioperative medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
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3
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Schulte A, Bieniussa L, Gupta R, Samtleben S, Bischler T, Doering K, Sodmann P, Rittner H, Blum R. Homeostatic calcium fluxes, ER calcium release, SOCE, and calcium oscillations in cultured astrocytes are interlinked by a small calcium toolkit. Cell Calcium 2021; 101:102515. [PMID: 34896701 DOI: 10.1016/j.ceca.2021.102515] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 11/29/2021] [Accepted: 11/30/2021] [Indexed: 12/27/2022]
Abstract
How homeostatic ER calcium fluxes shape cellular calcium signals is still poorly understood. Here we used dual-color calcium imaging (ER-cytosol) and transcriptome analysis to link candidates of the calcium toolkit of astrocytes with homeostatic calcium signals. We found molecular and pharmacological evidence that P/Q-type channel Cacna1a contributes to depolarization-dependent calcium entry in astrocytes. For stimulated ER calcium release, the cells express the phospholipase Cb3, IP3 receptors Itpr1 and Itpr2, but no ryanodine receptors (Ryr1-3). After IP3-induced calcium release, Stim1/2 - Orai1/2/3 most likely mediate SOCE. The Serca2 (Atp2a2) is the candidate for refilling of the ER calcium store. The cells highly express adenosine receptor Adora1a for IP3-induced calcium release. Accordingly, adenosine induces fast ER calcium release and subsequent ER calcium oscillations. After stimulation, calcium refilling of the ER depends on extracellular calcium. In response to SOCE, astrocytes show calcium-induced calcium release, notably even after ER calcium was depleted by extracellular calcium removal in unstimulated cells. In contrast, spontaneous ER-cytosol calcium oscillations were not fully dependent on extracellular calcium, as ER calcium oscillations could persist over minutes in calcium-free solution. Additionally, cell-autonomous calcium oscillations show a second-long spatial and temporal delay in the signal dynamics of ER and cytosolic calcium. Our data reveal a rather strong contribution of homeostatic calcium fluxes in shaping IP3-induced and calcium-induced calcium release as well as spatiotemporal components of intracellular calcium oscillations.
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Affiliation(s)
- Annemarie Schulte
- Department of Neurology, University Hospital of Würzburg, Würzburg, 97080 Germany; Institute of Clinical Neurobiology, University Hospital of Würzburg, Würzburg, 97078 Germany
| | - Linda Bieniussa
- Institute of Clinical Neurobiology, University Hospital of Würzburg, Würzburg, 97078 Germany; Department of Otorhinolaryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery, University Hospital Würzburg, Germany
| | - Rohini Gupta
- Department of Neurology, University Hospital of Würzburg, Würzburg, 97080 Germany; Institute of Clinical Neurobiology, University Hospital of Würzburg, Würzburg, 97078 Germany
| | - Samira Samtleben
- Institute of Clinical Neurobiology, University Hospital of Würzburg, Würzburg, 97078 Germany; Department of Cell Biology, University of Alberta, MSM, Edmonton, T6G 2H7 Canada
| | - Thorsten Bischler
- Core Unit Systems Medicine, University of Würzburg, Würzburg, 97080 Germany
| | - Kristina Doering
- Core Unit Systems Medicine, University of Würzburg, Würzburg, 97080 Germany; Department of Human Genetics, Ruhr University Bochum, Bochum, Germany
| | - Philipp Sodmann
- Department of Internal Medicine II, University Hospital of Würzburg, Würzburg, 97080 Germany
| | - Heike Rittner
- Department of Anesthesiology, Intensive Care, Emergency Medicine and Pain Therapy, University Hospital of Würzburg, Würzburg, 97074 Germany
| | - Robert Blum
- Department of Neurology, University Hospital of Würzburg, Würzburg, 97080 Germany; Institute of Clinical Neurobiology, University Hospital of Würzburg, Würzburg, 97078 Germany.
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Sharif N, Calzolari F, Berninger B. Direct In Vitro Reprogramming of Astrocytes into Induced Neurons. Methods Mol Biol 2021; 2352:13-29. [PMID: 34324177 DOI: 10.1007/978-1-0716-1601-7_2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Spontaneous neuronal replacement is almost absent in the postnatal mammalian nervous system. However, several studies have shown that both early postnatal and adult astroglia can be reprogrammed in vitro or in vivo by forced expression of proneural transcription factors, such as Neurogenin-2 or Achaete-scute homolog 1 (Ascl1), to acquire a neuronal fate. The reprogramming process stably induces properties such as distinctly neuronal morphology, expression of neuron-specific proteins, and the gain of mature neuronal functional features. Direct conversion of astroglia into neurons thus possesses potential as a basis for cell-based strategies against neurological diseases. In this chapter, we describe a well-established protocol used for direct reprogramming of postnatal cortical astrocytes into functional neurons in vitro and discuss available tools and approaches to dissect molecular and cell biological mechanisms underlying the reprogramming process.
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Affiliation(s)
- Nesrin Sharif
- Institute of Physiological Chemistry, University Medical Center Johannes Gutenberg University Mainz, Mainz, Germany
- International PhD Programme on Gene Regulation, Epigenetics and Genome Stability, Mainz, Germany
| | - Filippo Calzolari
- Institute of Physiological Chemistry, University Medical Center Johannes Gutenberg University Mainz, Mainz, Germany
| | - Benedikt Berninger
- Institute of Physiological Chemistry, University Medical Center Johannes Gutenberg University Mainz, Mainz, Germany.
- Institute of Psychiatry, Psychology, and Neuroscience, Centre for Developmental Neurobiology, King's College London, London, UK.
- MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK.
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5
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Janzen D, Bakirci E, Wieland A, Martin C, Dalton PD, Villmann C. Cortical Neurons form a Functional Neuronal Network in a 3D Printed Reinforced Matrix. Adv Healthc Mater 2020; 9:e1901630. [PMID: 32181992 DOI: 10.1002/adhm.201901630] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 02/17/2020] [Accepted: 03/04/2020] [Indexed: 12/15/2022]
Abstract
Impairments in neuronal circuits underly multiple neurodevelopmental and neurodegenerative disorders. 3D cell culture models enhance the complexity of in vitro systems and provide a microenvironment closer to the native situation than with 2D cultures. Such novel model systems will allow the assessment of neuronal network formation and their dysfunction under disease conditions. Here, mouse cortical neurons are cultured from embryonic day E17 within in a fiber-reinforced matrix. A soft Matrigel with a shear modulus of 31 ± 5.6 Pa is reinforced with scaffolds created by melt electrowriting, improving its mechanical properties and facilitating the handling. Cortical neurons display enhance cell viability and the neuronal network maturation in 3D, estimated by staining of dendrites and synapses over 21 days in vitro, is faster in 3D compared to 2D cultures. Using functional readouts with electrophysiological recordings, different firing patterns of action potentials are observed, which are absent in the presence of the sodium channel blocker, tetrodotoxin. Voltage-gated sodium currents display a current-voltage relationship with a maximum peak current at -25 mV. With its high customizability in terms of scaffold reinforcement and soft matrix formulation, this approach represents a new tool to study neuronal networks in 3D under normal and, potentially, disease conditions.
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Affiliation(s)
- Dieter Janzen
- Institute for Clinical NeurobiologyUniversity Hospital Würzburg Versbacherstr. 5 Würzburg 97078 Germany
| | - Ezgi Bakirci
- Department of Functional Materials in Medicine and Dentistry and Bavarian Polymer InstituteUniversity Hospital Würzburg Pleicherwall 2 Würzburg 97070 Germany
| | - Annalena Wieland
- Department of Obstetrics and GynecologyUniversity Hospital ErlangenLaboratory for Molecular MedicineFAU Erlangen‐Nürnberg Universitätsstrasse, 21–23 Erlangen 91054 Germany
| | - Corinna Martin
- Institute for Clinical NeurobiologyUniversity Hospital Würzburg Versbacherstr. 5 Würzburg 97078 Germany
| | - Paul D. Dalton
- Department of Functional Materials in Medicine and Dentistry and Bavarian Polymer InstituteUniversity Hospital Würzburg Pleicherwall 2 Würzburg 97070 Germany
| | - Carmen Villmann
- Institute for Clinical NeurobiologyUniversity Hospital Würzburg Versbacherstr. 5 Würzburg 97078 Germany
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6
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Aravantinou-Fatorou K, Thomaidou D. In Vitro Direct Reprogramming of Mouse and Human Astrocytes to Induced Neurons. Methods Mol Biol 2020; 2155:41-61. [PMID: 32474866 DOI: 10.1007/978-1-0716-0655-1_4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Direct neuronal reprogramming, rewiring the epigenetic and transcriptional network of a differentiated cell type to neuron, apart from being a very promising approach for the treatment of brain injury and neurodegeneration, also offers a prime opportunity to investigate the molecular underpinnings of neuronal cell fate determination, as the precise molecular mechanisms that establish neuronal fate and diversity at the transcriptional and epigenetic level are incompletely understood. Recent studies from a number of groups, including ours, have shown that astrocytes can be directly reprogrammed into functional neurons in vitro and in vivo following ectopic overexpression of combinations of transcription factors, neurogenic proteins, miRNAs, and small chemical molecules.In this chapter we describe the protocols for in vitro converting primary cortical astrocytes of mouse and human origin to induced neurons, through forced expression of two neurogenic molecules, either each one alone or in combination: the master regulatory bHLH proneural transcription factor NEUROGENIN-2 (NEUROG2) and the neurogenic protein CEND1. Forced expression of each one of the two neurogenic proteins in primary astrocytes via retroviral gene transfer results in their direct conversion to subtype-specific induced neurons, while simultaneous coexpression of both molecules drives them predominantly toward acquisition of a neural precursor cell (NPC) state. Although mouse and human astrocytes exhibit differences in their reprogramming rate and particular characteristics, they can both get efficiently in vitro transdifferentiated to NPCs and induced neurons upon NEUROG2 or/and CEND1 forced expression using the reprogramming protocols described in the chapter, presenting valuable cellular platforms for mechanistic studies and in vivo applications to restore neurodegeneration.
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Affiliation(s)
- Katerina Aravantinou-Fatorou
- Neural Stem Cells and Neuroimaging Group, Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| | - Dimitra Thomaidou
- Neural Stem Cells and Neuroimaging Group, Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece.
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7
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Vignoles R, Lentini C, d'Orange M, Heinrich C. Direct Lineage Reprogramming for Brain Repair: Breakthroughs and Challenges. Trends Mol Med 2019; 25:897-914. [PMID: 31371156 DOI: 10.1016/j.molmed.2019.06.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 06/17/2019] [Accepted: 06/20/2019] [Indexed: 01/10/2023]
Abstract
Injury to the human central nervous system (CNS) is devastating because our adult mammalian brain lacks intrinsic regenerative capacity to replace lost neurons and induce functional recovery. An emerging approach towards brain repair is to instruct fate conversion of brain-resident non-neuronal cells into induced neurons (iNs) by direct lineage reprogramming. Considerable progress has been made in converting various source cell types of mouse and human origin into clinically relevant iNs. Recent achievements using transcriptomics and epigenetics have shed light on the molecular mechanisms underpinning neuronal reprogramming, while the potential capability of iNs in promoting functional recovery in pathological contexts has started to be evaluated. Although future challenges need to be overcome before clinical translation, lineage reprogramming holds promise for effective cell-replacement therapy in regenerative medicine.
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Affiliation(s)
- Rory Vignoles
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, F-69500 Bron, France
| | - Célia Lentini
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, F-69500 Bron, France
| | - Marie d'Orange
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, F-69500 Bron, France
| | - Christophe Heinrich
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, F-69500 Bron, France.
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8
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Mokhtarzadeh Khanghahi A, Satarian L, Deng W, Baharvand H, Javan M. In vivo conversion of astrocytes into oligodendrocyte lineage cells with transcription factor Sox10; Promise for myelin repair in multiple sclerosis. PLoS One 2018; 13:e0203785. [PMID: 30212518 PMCID: PMC6136770 DOI: 10.1371/journal.pone.0203785] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 08/27/2018] [Indexed: 11/18/2022] Open
Abstract
Recent studies demonstrate that astroglial cells can be directly converted into functional neurons or oligodendrocytes. Here, we report that a single transcription factor Sox10 could reprogram astrocytes into oligodendrocyte-like cells, in vivo. For transdifferentiation, Sox10-GFP expressing viral particles were injected into cuprizone-induced demyelinated mice brains after which we assessed for the presence of specific oligodendrocyte lineage cell markers by immunohistofluorescence (IHF). As control, another group of demyelinated mice received GFP expressing viral particles. After 3 weeks, the majority of transduced (GFP+) cells in animals which received control vector were astrocytes, while in animals which received Sox10-GFP vector, the main population of GFP+ cells were positive for oligodendrocyte lineage markers. We also extracted primary astrocytes from mouse pups and purified them. Primary astrocytes were transduced in vitro and then transplanted into demyelinated brains for later fate mapping. After three weeks, in vitro transduced and then transplanted astrocytes showed oligodendrocyte progenitor and mature oligodendrocyte markers. Further confirmation was done by transduction of astrocytes with lentiviral particles that expressed Sox10 and GFP and their culture in the oligodendrocyte progenitor medium. The induced cells expressed oligodendrocyte progenitor cells (iOPCs) markers. Our findings showed the feasibility of reprogramming of astrocytes into oligodendrocyte-like cells in vivo, by using a single transcription factor, Sox10. This finding suggested a master regulatory role for Sox10 which enabled astrocytes to change their fate to OPC-like cells and establish an oligodendroglial phenotype. We hope this approach lead to effective myelin repair in patients suffering from myelination deficit.
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Affiliation(s)
- Akram Mokhtarzadeh Khanghahi
- Department of Brain Sciences and Cognition, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
| | - Leila Satarian
- Department of Brain Sciences and Cognition, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
| | - Wenbin Deng
- Institute for Pediatric Regenerative Medicine, University of California, Davis, School of Medicine, Sacramento, California, United States of America
| | - Hossein Baharvand
- Department of Brain Sciences and Cognition, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
- Department of Developmental Biology, University of Science and Culture, Tehran, Iran
| | - Mohammad Javan
- Department of Brain Sciences and Cognition, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
- * E-mail: ,
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9
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Ninkovic J, Götz M. Understanding direct neuronal reprogramming-from pioneer factors to 3D chromatin. Curr Opin Genet Dev 2018; 52:65-69. [PMID: 29909355 DOI: 10.1016/j.gde.2018.05.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/19/2018] [Accepted: 05/29/2018] [Indexed: 01/10/2023]
Abstract
Cell replacement therapies aim at reestablishment of neuronal circuits after brain injury, stroke or neurodegeneration. Recently, direct reprogramming of resident glial cells into the affected neuronal subtypes has become a feasible and promising option for central nervous system regeneration. Direct reprogramming relies on the implementation of a new transcriptional program defining the desired neuronal identity in fully differentiated glial cells implying the more or less complete down-regulation of the program for the former identity of the glial cell. Despite the enormous progress achieved in this regard with highly efficient in vivo reprogramming after injury, a number of hurdles still need to be resolved. One way to further improve direct neuronal reprogramming is to understand the molecular hurdles which we discuss with the focus on chromatin states of the starting versus the reprogrammed cells.
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Affiliation(s)
- Jovica Ninkovic
- Institute of Stem Cell Research, Helmholtz Center Munich, Germany; Physiological Genomics, Biomedical Center, University of Munich, Germany; Department for Cell Biology and Anatomy, Biomedical Center, University of Munich, Germany
| | - Magdalena Götz
- Institute of Stem Cell Research, Helmholtz Center Munich, Germany; Physiological Genomics, Biomedical Center, University of Munich, Germany; Munich Cluster for Systems Neurology SYNERGY, LMU, Munich, Germany.
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10
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Antonelli F, Casciati A, Tanori M, Tanno B, Linares-Vidal MV, Serra N, Bellés M, Pannicelli A, Saran A, Pazzaglia S. Alterations in Morphology and Adult Neurogenesis in the Dentate Gyrus of Patched1 Heterozygous Mice. Front Mol Neurosci 2018; 11:168. [PMID: 29875630 PMCID: PMC5974030 DOI: 10.3389/fnmol.2018.00168] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 05/03/2018] [Indexed: 01/06/2023] Open
Abstract
Many genes controlling neuronal development also regulate adult neurogenesis. We investigated in vivo the effect of Sonic hedgehog (Shh) signaling activation on patterning and neurogenesis of the hippocampus and behavior of Patched1 (Ptch1) heterozygous mice (Ptch1+/−). We demonstrated for the first time, that Ptch1+/− mice exhibit morphological, cellular and molecular alterations in the dentate gyrus (DG), including elongation and reduced width of the DG as well as deregulations at multiple steps during lineage progression from neural stem cells to neurons. By using stage-specific cellular markers, we detected reduction of quiescent stem cells, newborn neurons and astrocytes and accumulation of proliferating intermediate progenitors, indicative of defects in the dynamic transition among neural stages. Phenotypic alterations in Ptch1+/− mice were accompanied by expression changes in Notch pathway downstream components and TLX nuclear receptor, as well as perturbations in inflammatory and synaptic networks and mouse behavior, pointing to complex biological interactions and highlighting cooperation between Shh and Notch signaling in the regulation of neurogenesis.
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Affiliation(s)
- Francesca Antonelli
- Laboratory of Biomedical Technologies, Agenzia Nazionale per le Nuove Tecnologie, l'Energia e lo Sviluppo Economico Sostenibile (ENEA), Rome, Italy
| | - Arianna Casciati
- Laboratory of Biomedical Technologies, Agenzia Nazionale per le Nuove Tecnologie, l'Energia e lo Sviluppo Economico Sostenibile (ENEA), Rome, Italy
| | - Mirella Tanori
- Laboratory of Biomedical Technologies, Agenzia Nazionale per le Nuove Tecnologie, l'Energia e lo Sviluppo Economico Sostenibile (ENEA), Rome, Italy
| | - Barbara Tanno
- Laboratory of Biomedical Technologies, Agenzia Nazionale per le Nuove Tecnologie, l'Energia e lo Sviluppo Economico Sostenibile (ENEA), Rome, Italy
| | - Maria V Linares-Vidal
- Laboratory of Toxicology and Environmental Health, School of Medicine, Institut d'Investigació Sanitària Pere Virgili (IISPV), Rovira I Virgili University (URV), Reus, Spain.,Physiology Unit, School of Medicine, Institut d'Investigació Sanitària Pere Virgili (IISPV), Universitat Rovira i Virgili, Tarragona, Spain
| | - Noemi Serra
- Laboratory of Toxicology and Environmental Health, School of Medicine, Institut d'Investigació Sanitària Pere Virgili (IISPV), Rovira I Virgili University (URV), Reus, Spain.,Physiology Unit, School of Medicine, Institut d'Investigació Sanitària Pere Virgili (IISPV), Universitat Rovira i Virgili, Tarragona, Spain
| | - Monserrat Bellés
- Laboratory of Toxicology and Environmental Health, School of Medicine, Institut d'Investigació Sanitària Pere Virgili (IISPV), Rovira I Virgili University (URV), Reus, Spain.,Physiology Unit, School of Medicine, Institut d'Investigació Sanitària Pere Virgili (IISPV), Universitat Rovira i Virgili, Tarragona, Spain
| | - Alessandro Pannicelli
- Technical Unit of Energetic Efficiency, Agenzia Nazionale per le Nuove Tecnologie, l'Energia e lo Sviluppo Economico Sostenibile (ENEA), Rome, Italy
| | - Anna Saran
- Laboratory of Biomedical Technologies, Agenzia Nazionale per le Nuove Tecnologie, l'Energia e lo Sviluppo Economico Sostenibile (ENEA), Rome, Italy
| | - Simonetta Pazzaglia
- Laboratory of Biomedical Technologies, Agenzia Nazionale per le Nuove Tecnologie, l'Energia e lo Sviluppo Economico Sostenibile (ENEA), Rome, Italy
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11
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Prada J, Sasi M, Martin C, Jablonka S, Dandekar T, Blum R. An open source tool for automatic spatiotemporal assessment of calcium transients and local 'signal-close-to-noise' activity in calcium imaging data. PLoS Comput Biol 2018; 14:e1006054. [PMID: 29601577 PMCID: PMC5895056 DOI: 10.1371/journal.pcbi.1006054] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 04/11/2018] [Accepted: 02/22/2018] [Indexed: 01/06/2023] Open
Abstract
Local and spontaneous calcium signals play important roles in neurons and neuronal networks. Spontaneous or cell-autonomous calcium signals may be difficult to assess because they appear in an unpredictable spatiotemporal pattern and in very small neuronal loci of axons or dendrites. We developed an open source bioinformatics tool for an unbiased assessment of calcium signals in x,y-t imaging series. The tool bases its algorithm on a continuous wavelet transform-guided peak detection to identify calcium signal candidates. The highly sensitive calcium event definition is based on identification of peaks in 1D data through analysis of a 2D wavelet transform surface. For spatial analysis, the tool uses a grid to separate the x,y-image field in independently analyzed grid windows. A document containing a graphical summary of the data is automatically created and displays the loci of activity for a wide range of signal intensities. Furthermore, the number of activity events is summed up to create an estimated total activity value, which can be used to compare different experimental situations, such as calcium activity before or after an experimental treatment. All traces and data of active loci become documented. The tool can also compute the signal variance in a sliding window to visualize activity-dependent signal fluctuations. We applied the calcium signal detector to monitor activity states of cultured mouse neurons. Our data show that both the total activity value and the variance area created by a sliding window can distinguish experimental manipulations of neuronal activity states. Notably, the tool is powerful enough to compute local calcium events and ‘signal-close-to-noise’ activity in small loci of distal neurites of neurons, which remain during pharmacological blockade of neuronal activity with inhibitors such as tetrodotoxin, to block action potential firing, or inhibitors of ionotropic glutamate receptors. The tool can also offer information about local homeostatic calcium activity events in neurites. Calcium imaging has become a standard tool to investigate local, spontaneous, or cell-autonomous calcium signals in neurons. Some of these calcium signals are fast and ‘small’, thus making it difficult to identify real signaling events due to an unavoidable signal noise. Therefore, it is difficult to assess the spatiotemporal activity footprint of individual neurons or a neuronal network. We developed this open source tool to automatically extract, count, and localize calcium signals from the whole x,y-t image series. As demonstrated here, the tool is useful for an unbiased comparison of activity states of neurons, helps to assess local calcium transients, and even visualizes local homeostatic calcium activity. The tool is powerful enough to visualize signal-close-to-noise calcium activity.
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Affiliation(s)
- Juan Prada
- Department of Bioinformatics, University of Würzburg, Würzburg, Germany
| | - Manju Sasi
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Corinna Martin
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Sibylle Jablonka
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Thomas Dandekar
- Department of Bioinformatics, University of Würzburg, Würzburg, Germany
- * E-mail: (TD); (RB)
| | - Robert Blum
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
- * E-mail: (TD); (RB)
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12
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Chouchane M, Costa MR. Instructing neuronal identity during CNS development and astroglial-lineage reprogramming: Roles of NEUROG2 and ASCL1. Brain Res 2018; 1705:66-74. [PMID: 29510143 DOI: 10.1016/j.brainres.2018.02.045] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 02/16/2018] [Accepted: 02/27/2018] [Indexed: 01/02/2023]
Abstract
The adult mammalian brain contains an enormous variety of neuronal types, which are generally categorized in large groups, based on their neurochemical identity, hodological properties and molecular markers. This broad classification has allowed the correlation between individual neural progenitor populations and their neuronal progeny, thus contributing to probe the cellular and molecular mechanisms involved in neuronal identity determination during central nervous system (CNS) development. In this review, we discuss the contribution of the proneural genes Neurogenin2 (Neurog2) and Achaete-scute homolog 1 (Ascl1) for the specification of neuronal phenotypes in the developing neocortex, cerebellum and retina. Then, we revise recent data on astroglia cell lineage reprogramming into induced neurons using the same proneural proteins to compare the neuronal phenotypes obtained from astroglial cells originated in those CNS regions. We conclude that Ascl1 and Neurog2 have different contributions to determine neuronal fates, depending on the neural progenitor or astroglial population expressing those proneural factors. Finally, we discuss some possible explanations for these seemingly conflicting effects of Ascl1 and Neurog2 and propose future approaches to further dissect the molecular mechanisms of neuronal identity specification.
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Affiliation(s)
- Malek Chouchane
- Brain Institute, Federal University of Rio Grande do Norte, Natal 59072-970, Brazil; Neurological Surgery Department, University of California, San Francisco 94158, USA
| | - Marcos R Costa
- Brain Institute, Federal University of Rio Grande do Norte, Natal 59072-970, Brazil.
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13
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Li H, Chen G. In Vivo Reprogramming for CNS Repair: Regenerating Neurons from Endogenous Glial Cells. Neuron 2017; 91:728-738. [PMID: 27537482 DOI: 10.1016/j.neuron.2016.08.004] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Neuroregeneration in the CNS has proven to be difficult despite decades of research. The old dogma that CNS neurons cannot be regenerated in the adult mammalian brain has been overturned; however, endogenous adult neurogenesis appears to be insufficient for brain repair. Stem cell therapy once held promise for generating large quantities of neurons in the CNS, but immunorejection and long-term functional integration remain major hurdles. In this Perspective, we discuss the use of in vivo reprogramming as an emerging technology to regenerate functional neurons from endogenous glial cells inside the brain and spinal cord. Besides the CNS, in vivo reprogramming has been demonstrated successfully in the pancreas, heart, and liver and may be adopted in other organs. Although challenges remain for translating this technology into clinical therapies, we anticipate that in vivo reprogramming may revolutionize regenerative medicine by using a patient's own internal cells for tissue repair.
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Affiliation(s)
- Hedong Li
- Department of Biology, Huck Institutes of Life Sciences, Pennsylvania State University, University Park, PA 16802, USA.
| | - Gong Chen
- Department of Biology, Huck Institutes of Life Sciences, Pennsylvania State University, University Park, PA 16802, USA.
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14
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Wang Y, Ji X, Leak RK, Chen F, Cao G. Stem cell therapies in age-related neurodegenerative diseases and stroke. Ageing Res Rev 2017; 34:39-50. [PMID: 27876573 PMCID: PMC5250574 DOI: 10.1016/j.arr.2016.11.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Revised: 09/26/2016] [Accepted: 11/04/2016] [Indexed: 02/06/2023]
Abstract
Aging, a complex process associated with various structural, functional and metabolic changes in the brain, is an important risk factor for neurodegenerative diseases and stroke. These diseases share similar neuropathological changes, such as the formation of misfolded proteins, oxidative stress, loss of neurons and synapses, dysfunction of the neurovascular unit (NVU), reduction of self-repair capacity, and motor and/or cognitive deficiencies. In addition to gray matter dysfunction, the plasticity and repair capacity of white matter also decrease with aging and contribute to neurodegenerative diseases. Aging not only renders patients more susceptible to these disorders, but also attenuates their self-repair capabilities. In addition, low drug responsiveness and intolerable side effects are major challenges in the prevention and treatment of senile diseases. Thus, stem cell therapies-characterized by cellular plasticity and the ability to self-renew-may be a promising strategy for aging-related brain disorders. Here, we review the common pathophysiological changes, treatments, and the promises and limitations of stem cell therapies in age-related neurodegenerative diseases and stroke.
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Affiliation(s)
- Yuan Wang
- Departments of Neurology, Xuanwu Hospital, Capital University of Medicine, Beijing 100053, China
| | - Xunming Ji
- Departments of Neurosurgery, Xuanwu Hospital, Capital University of Medicine, Beijing 100053, China
| | - Rehana K Leak
- Division of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, United States
| | - Fenghua Chen
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, United States
| | - Guodong Cao
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, United States; Geriatric Research Education and Clinical Centers, VA Pittsburgh Healthcare System, Pittsburgh, PA 15240, United States.
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15
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Cholinergic Protection in Ischemic Brain Injury. SPRINGER SERIES IN TRANSLATIONAL STROKE RESEARCH 2017. [DOI: 10.1007/978-3-319-45345-3_17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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16
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Rusznák Z, Henskens W, Schofield E, Kim WS, Fu Y. Adult Neurogenesis and Gliogenesis: Possible Mechanisms for Neurorestoration. Exp Neurobiol 2016; 25:103-12. [PMID: 27358578 PMCID: PMC4923354 DOI: 10.5607/en.2016.25.3.103] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 06/08/2016] [Accepted: 06/08/2016] [Indexed: 12/22/2022] Open
Abstract
The subgranular zone (SGZ) and subventricular zone (SVZ) are developmental remnants of the germinal regions of the brain, hence they retain the ability to generate neuronal progenitor cells in adult life. Neurogenesis in adult brain has an adaptive function because newly produced neurons can integrate into and modify existing neuronal circuits. In contrast to the SGZ and SVZ, other brain regions have a lower capacity to produce new neurons, and this usually occurs via parenchymal and periventricular cell genesis. Compared to neurogenesis, gliogenesis occurs more prevalently in the adult mammalian brain. Under certain circumstances, interaction occurs between neurogenesis and gliogenesis, facilitating glial cells to transform into neuronal lineage. Therefore, modulating the balance between neurogenesis and gliogenesis may present a new perspective for neurorestoration, especially in diseases associated with altered neurogenesis and/or gliogenesis, cell loss, or disturbed homeostasis of cellular constitution. The present review discusses important neuroanatomical features of adult neurogenesis and gliogenesis, aiming to explore how these processes could be modulated toward functional repair of the adult brain.
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Affiliation(s)
- Zoltán Rusznák
- Neuroscience Research Australia, Sydney, NSW 2031, Australia
| | - Willem Henskens
- Neuroscience Research Australia, Sydney, NSW 2031, Australia.; Prince of Wales Clinical School, UNSW Medicine, University of New South Wales, Sydney, NSW 2052, Australia
| | - Emma Schofield
- Neuroscience Research Australia, Sydney, NSW 2031, Australia
| | - Woojin S Kim
- Neuroscience Research Australia, Sydney, NSW 2031, Australia.; School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - YuHong Fu
- Neuroscience Research Australia, Sydney, NSW 2031, Australia.; School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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17
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Jones KS, Connor BJ. The Effect of Pro-Neurogenic Gene Expression on Adult Subventricular Zone Precursor Cell Recruitment and Fate Determination After Excitotoxic Brain Injury. J Stem Cells Regen Med 2016. [PMID: 27397999 PMCID: PMC4929891 DOI: 10.46582/jsrm.1201005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Despite the presence of on-going neurogenesis in the adult mammalian brain, neurons are generally not replaced after injury. Using a rodent model of excitotoxic cell loss and retroviral (RV) lineage tracing, we previously demonstrated transient recruitment of precursor cells from the subventricular zone (SVZ) into the lesioned striatum. In the current study we determined that these cells included migratory neuroblasts and oligodendrocyte precursor cells (OPC), with the predominant response from glial cells. We attempted to override this glial response by ectopic expression of the pro-neurogenic genes Pax6 or Dlx2 in the adult rat SVZ following quinolinic acid lesioning. RV-Dlx2 over-expression stimulated repair at a previously non-neurogenic time point by enhancing neuroblast recruitment and the percentage of cells that retained a neuronal fate within the lesioned area, compared to RV-GFP controls. RV-Pax6 expression was unsuccessful at inhibiting glial fate and intriguingly, increased OPC cell numbers with no change in neuronal recruitment. These findings suggest that gene choice is important when attempting to augment endogenous repair as the lesioned environment can overcome pro-neurogenic gene expression. Dlx2 over-expression however was able to partially overcome an anti-neuronal environment and therefore is a promising candidate for further study of striatal regeneration.
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Affiliation(s)
- Kathryn S Jones
- Centre for Brain Research, Department of Pharmacology and Clinical Pharmacology, School of Medical Science, Faculty of Medical and Health Sciences, University of Auckland
| | - Bronwen J Connor
- Centre for Brain Research, Department of Pharmacology and Clinical Pharmacology, School of Medical Science, Faculty of Medical and Health Sciences, University of Auckland
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18
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Gascón S, Murenu E, Masserdotti G, Ortega F, Russo GL, Petrik D, Deshpande A, Heinrich C, Karow M, Robertson SP, Schroeder T, Beckers J, Irmler M, Berndt C, Angeli JPF, Conrad M, Berninger B, Götz M. Identification and Successful Negotiation of a Metabolic Checkpoint in Direct Neuronal Reprogramming. Cell Stem Cell 2015; 18:396-409. [PMID: 26748418 DOI: 10.1016/j.stem.2015.12.003] [Citation(s) in RCA: 242] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 11/07/2015] [Accepted: 12/10/2015] [Indexed: 11/16/2022]
Abstract
Despite the widespread interest in direct neuronal reprogramming, the mechanisms underpinning fate conversion remain largely unknown. Our study revealed a critical time point after which cells either successfully convert into neurons or succumb to cell death. Co-transduction with Bcl-2 greatly improved negotiation of this critical point by faster neuronal differentiation. Surprisingly, mutants with reduced or no affinity for Bax demonstrated that Bcl-2 exerts this effect by an apoptosis-independent mechanism. Consistent with a caspase-independent role, ferroptosis inhibitors potently increased neuronal reprogramming by inhibiting lipid peroxidation occurring during fate conversion. Genome-wide expression analysis confirmed that treatments promoting neuronal reprogramming elicit an anti-oxidative stress response. Importantly, co-expression of Bcl-2 and anti-oxidative treatments leads to an unprecedented improvement in glial-to-neuron conversion after traumatic brain injury in vivo, underscoring the relevance of these pathways in cellular reprograming irrespective of cell type in vitro and in vivo.
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Affiliation(s)
- Sergio Gascón
- Physiological Genomics, Biomedical Center Ludwig-Maximilians-University Munich, 80336 Munich, Germany; Institute for Stem Cell Research, Helmholtz Center Munich, 85764 Neuherberg, Germany.
| | - Elisa Murenu
- Physiological Genomics, Biomedical Center Ludwig-Maximilians-University Munich, 80336 Munich, Germany; Institute for Stem Cell Research, Helmholtz Center Munich, 85764 Neuherberg, Germany
| | - Giacomo Masserdotti
- Physiological Genomics, Biomedical Center Ludwig-Maximilians-University Munich, 80336 Munich, Germany; Institute for Stem Cell Research, Helmholtz Center Munich, 85764 Neuherberg, Germany
| | - Felipe Ortega
- Physiological Genomics, Biomedical Center Ludwig-Maximilians-University Munich, 80336 Munich, Germany; Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, 55128 Mainz, Germany; Biochemistry and Molecular Biology Department, Faculty of Veterinary Medicine, Complutense University, Avenue Puerta de Hierro, 28040 Madrid, Spain
| | - Gianluca L Russo
- Physiological Genomics, Biomedical Center Ludwig-Maximilians-University Munich, 80336 Munich, Germany; Institute for Stem Cell Research, Helmholtz Center Munich, 85764 Neuherberg, Germany
| | - David Petrik
- Physiological Genomics, Biomedical Center Ludwig-Maximilians-University Munich, 80336 Munich, Germany; Institute for Stem Cell Research, Helmholtz Center Munich, 85764 Neuherberg, Germany
| | - Aditi Deshpande
- Physiological Genomics, Biomedical Center Ludwig-Maximilians-University Munich, 80336 Munich, Germany
| | - Christophe Heinrich
- Physiological Genomics, Biomedical Center Ludwig-Maximilians-University Munich, 80336 Munich, Germany
| | - Marisa Karow
- Physiological Genomics, Biomedical Center Ludwig-Maximilians-University Munich, 80336 Munich, Germany
| | - Stephen P Robertson
- Department of Women's and Children's Health, Dunedin School of Medicine, University of Otago, 9016 Dunedin, New Zealand
| | - Timm Schroeder
- Research Unit Stem Cell Dynamics, Helmholtz Center Munich, Neuherberg, 85764 Neuherberg, Germany
| | - Johannes Beckers
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Institute of Experimental Genetics, Helmholtz Center Munich GmbH, 85764 Neuherberg, Germany; Center of Life and Food Sciences Weihenstephan, Technical University Munich, 85354 Freising, Germany
| | - Martin Irmler
- Institute of Experimental Genetics, Helmholtz Center Munich GmbH, 85764 Neuherberg, Germany
| | - Carsten Berndt
- Department of Neurology, Medical Faculty, Heinrich-Heine University Düsseldorf, Merowingerplatz 1a, 40225 Düsseldorf, Germany
| | | | - Marcus Conrad
- Institute of Developmental Genetics, Helmholtz Center Munich, 85764 Neuherberg, Germany
| | - Benedikt Berninger
- Physiological Genomics, Biomedical Center Ludwig-Maximilians-University Munich, 80336 Munich, Germany; Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, 55128 Mainz, Germany; Focus Program Translational Neuroscience, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Magdalena Götz
- Physiological Genomics, Biomedical Center Ludwig-Maximilians-University Munich, 80336 Munich, Germany; Institute for Stem Cell Research, Helmholtz Center Munich, 85764 Neuherberg, Germany; Excellence Cluster of Systems Neurology (SYNERGY), 80336 Munich, Germany.
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19
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Liu Z, Chopp M. Astrocytes, therapeutic targets for neuroprotection and neurorestoration in ischemic stroke. Prog Neurobiol 2015; 144:103-20. [PMID: 26455456 DOI: 10.1016/j.pneurobio.2015.09.008] [Citation(s) in RCA: 393] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 08/06/2015] [Accepted: 09/05/2015] [Indexed: 01/04/2023]
Abstract
Astrocytes are the most abundant cell type within the central nervous system. They play essential roles in maintaining normal brain function, as they are a critical structural and functional part of the tripartite synapses and the neurovascular unit, and communicate with neurons, oligodendrocytes and endothelial cells. After an ischemic stroke, astrocytes perform multiple functions both detrimental and beneficial, for neuronal survival during the acute phase. Aspects of the astrocytic inflammatory response to stroke may aggravate the ischemic lesion, but astrocytes also provide benefit for neuroprotection, by limiting lesion extension via anti-excitotoxicity effects and releasing neurotrophins. Similarly, during the late recovery phase after stroke, the glial scar may obstruct axonal regeneration and subsequently reduce the functional outcome; however, astrocytes also contribute to angiogenesis, neurogenesis, synaptogenesis, and axonal remodeling, and thereby promote neurological recovery. Thus, the pivotal involvement of astrocytes in normal brain function and responses to an ischemic lesion designates them as excellent therapeutic targets to improve functional outcome following stroke. In this review, we will focus on functions of astrocytes and astrocyte-mediated events during stroke and recovery. We will provide an overview of approaches on how to reduce the detrimental effects and amplify the beneficial effects of astrocytes on neuroprotection and on neurorestoration post stroke, which may lead to novel and clinically relevant therapies for stroke.
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Affiliation(s)
- Zhongwu Liu
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA.
| | - Michael Chopp
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA; Department of Physics, Oakland University, Rochester, MI, USA
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20
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Bradford AB, McNutt PM. Importance of being Nernst: Synaptic activity and functional relevance in stem cell-derived neurons. World J Stem Cells 2015; 7:899-921. [PMID: 26240679 PMCID: PMC4515435 DOI: 10.4252/wjsc.v7.i6.899] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 02/28/2015] [Accepted: 05/11/2015] [Indexed: 02/06/2023] Open
Abstract
Functional synaptogenesis and network emergence are signature endpoints of neurogenesis. These behaviors provide higher-order confirmation that biochemical and cellular processes necessary for neurotransmitter release, post-synaptic detection and network propagation of neuronal activity have been properly expressed and coordinated among cells. The development of synaptic neurotransmission can therefore be considered a defining property of neurons. Although dissociated primary neuron cultures readily form functioning synapses and network behaviors in vitro, continuously cultured neurogenic cell lines have historically failed to meet these criteria. Therefore, in vitro-derived neuron models that develop synaptic transmission are critically needed for a wide array of studies, including molecular neuroscience, developmental neurogenesis, disease research and neurotoxicology. Over the last decade, neurons derived from various stem cell lines have shown varying ability to develop into functionally mature neurons. In this review, we will discuss the neurogenic potential of various stem cells populations, addressing strengths and weaknesses of each, with particular attention to the emergence of functional behaviors. We will propose methods to functionally characterize new stem cell-derived neuron (SCN) platforms to improve their reliability as physiological relevant models. Finally, we will review how synaptically active SCNs can be applied to accelerate research in a variety of areas. Ultimately, emphasizing the critical importance of synaptic activity and network responses as a marker of neuronal maturation is anticipated to result in in vitro findings that better translate to efficacious clinical treatments.
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21
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The Neurogenic Potential of Astrocytes Is Regulated by Inflammatory Signals. Mol Neurobiol 2015; 53:3724-3739. [PMID: 26138449 PMCID: PMC4937102 DOI: 10.1007/s12035-015-9296-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 06/08/2015] [Indexed: 01/01/2023]
Abstract
Although the adult brain contains neural stem cells (NSCs) that generate new neurons throughout life, these astrocyte-like populations are restricted to two discrete niches. Despite their terminally differentiated phenotype, adult parenchymal astrocytes can re-acquire NSC-like characteristics following injury, and as such, these ‘reactive’ astrocytes offer an alternative source of cells for central nervous system (CNS) repair following injury or disease. At present, the mechanisms that regulate the potential of different types of astrocytes are poorly understood. We used in vitro and ex vivo astrocytes to identify candidate pathways important for regulation of astrocyte potential. Using in vitro neural progenitor cell (NPC)-derived astrocytes, we found that exposure of more lineage-restricted astrocytes to either tumor necrosis factor alpha (TNF-α) (via nuclear factor-κB (NFκB)) or the bone morphogenetic protein (BMP) inhibitor, noggin, led to re-acquisition of NPC properties accompanied by transcriptomic and epigenetic changes consistent with a more neurogenic, NPC-like state. Comparative analyses of microarray data from in vitro-derived and ex vivo postnatal parenchymal astrocytes identified several common pathways and upstream regulators associated with inflammation (including transforming growth factor (TGF)-β1 and peroxisome proliferator-activated receptor gamma (PPARγ)) and cell cycle control (including TP53) as candidate regulators of astrocyte phenotype and potential. We propose that inflammatory signalling may control the normal, progressive restriction in potential of differentiating astrocytes as well as under reactive conditions and represent future targets for therapies to harness the latent neurogenic capacity of parenchymal astrocytes.
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22
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Therapeutical Strategies for Spinal Cord Injury and a Promising Autologous Astrocyte-Based Therapy Using Efficient Reprogramming Techniques. Mol Neurobiol 2015; 53:2826-2842. [DOI: 10.1007/s12035-015-9157-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 03/19/2015] [Indexed: 01/01/2023]
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23
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Heinrich C, Rouaux C. [Inducing brain regeneration from within: in vivo reprogramming of endogenous somatic cells into neurons]. Med Sci (Paris) 2015; 31:35-42. [PMID: 25658729 DOI: 10.1051/medsci/20153101011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
In order to overcome the quasi-total inability of the mammalian central nervous system to regenerate in response to injuries, and in parallel to the studies dedicated to prevent neuronal loss under these circumstances, alternative approaches based on the programming of pluripotent cells or the reprogramming of somatic cells into neurons have recently emerged. These uniquely combine growing knowledge of the mechanisms that underlie neurogenesis and neuronal specification during development to the most recent findings of the molecular and epigenetic mechanisms that govern the acquisition and maintenance of cellular identity. Here, we discuss the possibility to instruct the regeneration of the central nervous system from within for therapeutic purposes, in light of the recent works reporting on the generation of neurons by direct conversion of various cerebral cell types in vitro and in vivo.
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Affiliation(s)
- Christophe Heinrich
- Inserm U836, institut des neurosciences de Grenoble, centre de recherche Inserm U836-UJF-CHU, université Joseph Fourier, 38042 Grenoble Cedex 9, France
| | - Caroline Rouaux
- Inserm U1118, fédération de médecine translationnelle de Strasbourg, université de Strasbourg, 67085 Strasbourg, France
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24
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Chang TY, Shi P, Steinmeyer JD, Chatnuntawech I, Tillberg P, Love KT, Eimon PM, Anderson DG, Yanik MF. Organ-targeted high-throughput in vivo biologics screen identifies materials for RNA delivery. Integr Biol (Camb) 2014; 6:926-34. [PMID: 25184623 PMCID: PMC4350364 DOI: 10.1039/c4ib00150h] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Therapies based on biologics involving delivery of proteins, DNA, and RNA are currently among the most promising approaches. However, although large combinatorial libraries of biologics and delivery vehicles can be readily synthesized, there are currently no means to rapidly characterize them in vivo using animal models. Here, we demonstrate high-throughput in vivo screening of biologics and delivery vehicles by automated delivery into target tissues of small vertebrates with developed organs. Individual zebrafish larvae are automatically oriented and immobilized within hydrogel droplets in an array format using a microfluidic system, and delivery vehicles are automatically microinjected to target organs with high repeatability and precision. We screened a library of lipid-like delivery vehicles for their ability to facilitate the expression of protein-encoding RNAs in the central nervous system. We discovered delivery vehicles that are effective in both larval zebrafish and rats. Our results showed that the in vivo zebrafish model can be significantly more predictive of both false positives and false negatives in mammals than in vitro mammalian cell culture assays. Our screening results also suggest certain structure-activity relationships, which can potentially be applied to design novel delivery vehicles.
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Affiliation(s)
- Tsung-Yao Chang
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Peng Shi
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Joseph D. Steinmeyer
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Itthi Chatnuntawech
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Paul Tillberg
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Kevin T. Love
- Department of Chemical Engineering, Institute of Medical Engineering and Science, Division of Health Science and Technology, David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Peter M. Eimon
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Daniel G. Anderson
- Department of Chemical Engineering, Institute of Medical Engineering and Science, Division of Health Science and Technology, David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Mehmet Fatih Yanik
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- ETH, Zurich, Switzerland
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25
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Instant neurons: directed somatic cell reprogramming models of central nervous system disorders. Biol Psychiatry 2014; 75:945-51. [PMID: 24525100 DOI: 10.1016/j.biopsych.2013.10.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 09/21/2013] [Accepted: 10/12/2013] [Indexed: 12/30/2022]
Abstract
Nuclear transplantation, cell fusion, and induced pluripotent stem cell studies have revealed a surprising degree of plasticity in mature mammalian cell fates. Somatic cell reprogramming also has been achieved more recently by the directed conversion of nonneuronal somatic cells, such as skin fibroblasts, to neuronal phenotypes. This approach appears particularly applicable to the in vitro modeling of human neurologic disorders. Central nervous system neurons are otherwise difficult to obtain from patients with neurologic disorders; however, nonhuman models may not reflect patient pathology. Somatic cell reprogramming may afford models of nonfamilial "sporadic" neurologic disorders, which are likely caused by multiple interacting genetic and nongenetic factors. Directed somatic cell reprogramming, which does not pass through typical in vivo developmental stages, toward many mature neuronal phenotypes has now been described. This article reviews the field and discusses the potential utilities of such models, such as for the development of personalized medicine strategies.
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Ang CE, Wernig M. Induced neuronal reprogramming. J Comp Neurol 2014; 522:2877-86. [PMID: 24771471 DOI: 10.1002/cne.23620] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 04/24/2014] [Accepted: 04/25/2014] [Indexed: 12/21/2022]
Abstract
Cellular differentiation processes during normal embryonic development are guided by extracellular soluble factors such as morphogen gradients and cell contact signals, eventually resulting in induction of specific combinations of lineage-determining transcription factors. The young field of epigenetic reprogramming takes advantage of this knowledge and uses cell fate determination factors to convert one lineage into another such as the conversion of fibroblasts into pluripotent stem cells or neurons. These induced cell fate conversions open up new avenues for studying disease processes, generating cell material for therapeutic intervention such as drug screening and potentially also for cell-based therapies. However, there are still limitations that have to be overcome to fulfill these promises, centering on reprogramming efficiencies, cell identity, and maturation. In this review, we discuss the discovery of induced neuronal reprogramming, ways to improve the conversion process, and finally how to define properly the identity of those converted neuronal cells.
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Affiliation(s)
- Cheen Euong Ang
- Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University School of Medicine, Stanford, California, 94305; Department of Bioengineering, Stanford University School of Medicine, Stanford, California, 94305
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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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Pollak J, Wilken MS, Ueki Y, Cox KE, Sullivan JM, Taylor RJ, Levine EM, Reh TA. ASCL1 reprograms mouse Muller glia into neurogenic retinal progenitors. Development 2013; 140:2619-31. [PMID: 23637330 PMCID: PMC3666387 DOI: 10.1242/dev.091355] [Citation(s) in RCA: 164] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/03/2013] [Indexed: 12/14/2022]
Abstract
Non-mammalian vertebrates have a robust ability to regenerate injured retinal neurons from Müller glia (MG) that activate the gene encoding the proneural factor Achaete-scute homolog 1 (Ascl1; also known as Mash1 in mammals) and de-differentiate into progenitor cells. By contrast, mammalian MG have a limited regenerative response and fail to upregulate Ascl1 after injury. To test whether ASCL1 could restore neurogenic potential to mammalian MG, we overexpressed ASCL1 in dissociated mouse MG cultures and intact retinal explants. ASCL1-infected MG upregulated retinal progenitor-specific genes and downregulated glial genes. Furthermore, ASCL1 remodeled the chromatin at its targets from a repressive to an active configuration. MG-derived progenitors differentiated into cells that exhibited neuronal morphologies, expressed retinal subtype-specific neuronal markers and displayed neuron-like physiological responses. These results indicate that a single transcription factor, ASCL1, can induce a neurogenic state in mature MG.
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Affiliation(s)
- Julia Pollak
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
- Neurobiology and Behavior Program, University of Washington, Seattle, WA 98195, USA
| | - Matthew S. Wilken
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98195, USA
| | - Yumi Ueki
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Kristen E. Cox
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Jane M. Sullivan
- Neurobiology and Behavior Program, University of Washington, Seattle, WA 98195, USA
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
| | - Russell J. Taylor
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Edward M. Levine
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA
| | - Thomas A. Reh
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
- Neurobiology and Behavior Program, University of Washington, Seattle, WA 98195, USA
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98195, USA
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Walcher T, Xie Q, Sun J, Irmler M, Beckers J, Öztürk T, Niessing D, Stoykova A, Cvekl A, Ninkovic J, Götz M. Functional dissection of the paired domain of Pax6 reveals molecular mechanisms of coordinating neurogenesis and proliferation. Development 2013; 140:1123-36. [PMID: 23404109 DOI: 10.1242/dev.082875] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
To achieve adequate organ development and size, cell proliferation and differentiation have to be tightly regulated and coordinated. The transcription factor Pax6 regulates patterning, neurogenesis and proliferation in forebrain development. The molecular basis of this regulation is not well understood. As the bipartite DNA-binding paired domain of Pax6 regulates forebrain development, we examined mice with point mutations in its individual DNA-binding subdomains PAI (Pax6(Leca4), N50K) and RED (Pax6(Leca2), R128C). This revealed distinct roles in regulating proliferation in the developing cerebral cortex, with the PAI and RED subdomain mutations reducing and increasing, respectively, the number of mitoses. Conversely, neurogenesis was affected only by the PAI subdomain mutation, phenocopying the neurogenic defects observed in full Pax6 mutants. Genome-wide expression profiling identified molecularly discrete signatures of Pax6(Leca4) and Pax6(Leca2) mutations. Comparison to Pax6 targets identified by chromatin immunoprecipitation led to the identification and functional characterization of distinct DNA motifs in the promoters of target genes dysregulated in the Pax6(Leca2) or Pax6(Leca4) mutants, further supporting the distinct regulatory functions of the DNA-binding subdomains. Thus, Pax6 achieves its key roles in the developing forebrain by utilizing particular subdomains to coordinate patterning, neurogenesis and proliferation simultaneously.
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Affiliation(s)
- Tessa Walcher
- Institute of Stem Cell Research, Helmholtz Center Munich, 85764 Neuherberg-Munich, Germany
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30
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Ninkovic J, Götz M. Fate specification in the adult brain - lessons for eliciting neurogenesis from glial cells. Bioessays 2013; 35:242-52. [DOI: 10.1002/bies.201200108] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Chouchane M, Costa MR. Cell therapy for stroke: use of local astrocytes. Front Cell Neurosci 2012; 6:49. [PMID: 23118728 PMCID: PMC3484360 DOI: 10.3389/fncel.2012.00049] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 10/12/2012] [Indexed: 01/09/2023] Open
Abstract
Stroke refers to a variety of conditions caused by the occlusion or hemorrhage of blood vessels supplying the brain, which is one of the main causes of death and the leading cause of disability worldwide. In the last years, cell-based therapies have been proposed as a new approach to ameliorate post-stroke deficits. However, the most appropriate type of cell to be used in such therapies, as well as their sources, remains a matter of intense research. A good candidate cell should, in principle, display high plasticity to generate diverse types of neurons and, at the same time, low risk to cause undesired outcomes, such as malignant transformation. Recently, a new approach grounded on the reprogramming of endogenous astrocytes toward neuronal fates emerged as an alternative to restore neurological functions in several central nervous system diseases. In this perspective, we review data about the potential of astrocytes to become functional neurons following expression of neurogenic genes and discuss the potential benefits and risks of reprogramming astrocytes in the glial scar to replace neurons lost after stroke.
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Affiliation(s)
- Melek Chouchane
- Brain Institute, Federal University of Rio Grande do Norte Natal, Brazil
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32
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Feliciano DM, Bordey A. Newborn cortical neurons: only for neonates? Trends Neurosci 2012; 36:51-61. [PMID: 23062965 DOI: 10.1016/j.tins.2012.09.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 08/08/2012] [Accepted: 09/18/2012] [Indexed: 01/19/2023]
Abstract
Despite a century of debate over the existence of adult cortical neurogenesis, a consensus has not yet been reached. Here, we review evidence of the existence, origin, migration, and integration of neurons into the adult and neonatal cerebral cortex. We find that the lack of consensus likely stems from the low rate of postnatal cortical neurogenesis that has been observed, the fact that neurogenesis may be limited to subtypes of interneurons, and variability in other conditions, both physiological and environmental. We emphasize that neurogenesis occurs in the neonatal cortex and that neural stem cells are present into adulthood; it is possible that these progenitors are dormant, but they may be reactivated, for example, following injury.
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Affiliation(s)
- David M Feliciano
- Department of Neurosurgery, and Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520, USA
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33
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Kizil C, Kaslin J, Kroehne V, Brand M. Adult neurogenesis and brain regeneration in zebrafish. Dev Neurobiol 2012; 72:429-61. [DOI: 10.1002/dneu.20918] [Citation(s) in RCA: 249] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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34
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Abstract
Classic experiments such as somatic cell nuclear transfer into oocytes and cell fusion demonstrated that differentiated cells are not irreversibly committed to their fate. More recent work has built on these conclusions and discovered defined factors that directly induce one specific cell type from another, which may be as distantly related as cells from different germ layers. This suggests the possibility that any specific cell type may be directly converted into any other if the appropriate reprogramming factors are known. Direct lineage conversion could provide important new sources of human cells for modeling disease processes or for cellular-replacement therapies. For future applications, it will be critical to carefully determine the fidelity of reprogramming and to develop methods for robustly and efficiently generating human cell types of interest.
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Affiliation(s)
- Thomas Vierbuchen
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
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35
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Heinrich C, Götz M, Berninger B. Reprogramming of postnatal astroglia of the mouse neocortex into functional, synapse-forming neurons. Methods Mol Biol 2012; 814:485-98. [PMID: 22144327 DOI: 10.1007/978-1-61779-452-0_32] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Direct conversion of glia into neurons by cellular reprogramming represents a novel approach toward a cell-based therapy of neurodegenerative processes. Here we describe a protocol that allows for the direct and efficient in vitro reprogramming of mouse astroglia from the early postnatal neocortex by forced expression of single neurogenic fate determinants. By selective retrovirus-mediated expression of neurogenin-2 (Neurog2) on the one hand, or the mouse homologue of Distal-less Dlx2 or the mammalian homologue of achaete-schute-1 (Mash1) on the other, it is possible to drive postnatal astroglia in culture toward the genesis of fully functional, synapse-forming, glutamatergic, i.e., excitatory, and GABAergic, i.e., inhibitory, neurons, respectively.
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Affiliation(s)
- Christophe Heinrich
- Department of Physiological Genomics, Institute of Physiology, Ludwig-Maximilians University Munich, Munich, Germany
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36
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Hansen DV, Rubenstein JLR, Kriegstein AR. Deriving excitatory neurons of the neocortex from pluripotent stem cells. Neuron 2011; 70:645-60. [PMID: 21609822 DOI: 10.1016/j.neuron.2011.05.006] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2011] [Indexed: 01/17/2023]
Abstract
The human cerebral cortex is an immensely complex structure that subserves critical functions that can be disrupted in developmental and degenerative disorders. Recent innovations in cellular reprogramming and differentiation techniques have provided new ways to study the cellular components of the cerebral cortex. Here, we discuss approaches to generate specific subtypes of excitatory cortical neurons from pluripotent stem cells. We review spatial and temporal aspects of cortical neuron specification that can guide efforts to produce excitatory neuron subtypes with increased resolution. Finally, we discuss distinguishing features of human cortical development and their translational ramifications for cortical stem cell technologies.
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Affiliation(s)
- David V Hansen
- Department of Neurology, University of California, San Francisco, CA 94143, USA
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37
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Weinandy F, Ninkovic J, Götz M. Restrictions in time and space--new insights into generation of specific neuronal subtypes in the adult mammalian brain. Eur J Neurosci 2011; 33:1045-54. [PMID: 21395847 DOI: 10.1111/j.1460-9568.2011.07602.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Key questions in regard to neuronal repair strategies are which cells are best suited to regenerate specific neuronal subtypes and how much of a neuronal circuit needs to persist in order to allow its functional repair. Here we discuss recent findings in the field of adult neurogenesis, which shed new light on these questions. Neural stem cells in the adult brain generate very distinct types of neurons depending on their regional and temporal specification. Moreover, distinct brain regions differ in the mode of neuron addition in adult neurogenesis, suggesting that different brain circuits may be able to cope differently with the incorporation of new neurons. These new insights are then considered in regard to the choice of cells with the appropriate region-specific identity for repair strategies.
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Affiliation(s)
- Franziska Weinandy
- Institute of Stem Cell Research, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstr. 1, 85764 München/Neuherberg, Germany
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38
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Zhang L, Li P, Hsu T, Aguilar HR, Frantz DE, Schneider JW, Bachoo RM, Hsieh J. Small-molecule blocks malignant astrocyte proliferation and induces neuronal gene expression. Differentiation 2011; 81:233-42. [PMID: 21419563 DOI: 10.1016/j.diff.2011.02.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 01/06/2011] [Accepted: 02/23/2011] [Indexed: 10/18/2022]
Abstract
In the central nervous system (CNS), neural stem cells (NSCs) differentiate into neurons, astrocytes, and oligodendrocytes--these cell lineages are considered unidirectional and irreversible under normal conditions. The introduction of a defined set of transcription factors has been shown to directly convert terminally differentiated cells into pluripotent stem cells, reinforcing the notion that preserving cellular identity is an active process. Indeed, recent studies highlight that tumor suppressor genes (TSGs) such as Ink4a/Arf and p53, control the barrier to efficient reprogramming, leaving open the question whether the same TSGs function to maintain the differentiated state. During malignancy or following brain injury, mature astrocytes have been reported to re-express neuronal genes and re-gain neurogenic potential to a certain degree, yet few studies have addressed the underlying mechanisms due to a limited number of cellular models or tools to probe this process. Here, we use a synthetic small-molecule (isoxazole) to demonstrate that highly malignant EGFRvIII-expressing Ink4a/Arf(-/-); Pten(-/-) astrocytes downregulated their astrocyte character, re-entered the cell cycle, and upregulated neuronal gene expression. As a collateral discovery, isoxazole small-molecules blocked tumor cell proliferation in vitro, a phenotype likely coupled to activation of neuronal gene expression. Similarly, histone deacetylase inhibitors induced neuronal gene expression and morphologic changes associated with the neuronal phenotype, suggesting the involvement of epigenetic-mediated gene activation. Our study assesses the contribution of specific genetic pathways underlying the de-differentiation potential of astrocytes and uncovers a novel pharmacological tool to explore astrocyte plasticity, which may bring insight to reprogramming and anti-tumor strategies.
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Affiliation(s)
- Ling Zhang
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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39
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Robel S, Berninger B, Götz M. The stem cell potential of glia: lessons from reactive gliosis. Nat Rev Neurosci 2011; 12:88-104. [PMID: 21248788 DOI: 10.1038/nrn2978] [Citation(s) in RCA: 388] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Astrocyte-like cells, which act as stem cells in the adult brain, reside in a few restricted stem cell niches. However, following brain injury, glia outside these niches acquire or reactivate stem cell potential as part of reactive gliosis. Recent studies have begun to uncover the molecular pathways involved in this process. A comparison of molecular pathways activated after injury with those involved in the normal neural stem cell niches highlights strategies that could overcome the inhibition of neurogenesis outside the stem cell niche and instruct parenchymal glia towards a neurogenic fate. This new view on reactive glia therefore suggests a widespread endogenous source of cells with stem cell potential, which might potentially be harnessed for local repair strategies.
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Affiliation(s)
- Stefanie Robel
- Physiological Genomics, Ludwig-Maximilians University of Munich, Germany
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40
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Generation of subtype-specific neurons from postnatal astroglia of the mouse cerebral cortex. Nat Protoc 2011; 6:214-28. [PMID: 21293461 DOI: 10.1038/nprot.2010.188] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Instructing glial cells to generate neurons may prove to be a strategy to replace neurons that have degenerated. Here, we describe a robust protocol for the efficient in vitro conversion of postnatal astroglia from the mouse cerebral cortex into functional, synapse-forming neurons. This protocol involves two steps: (i) expansion of astroglial cells (7 d) and (ii) astroglia-to-neuron conversion induced by persistent and strong retroviral expression of Neurog2 (encoding neurogenin-2) or Mash1 (also referred to as achaete-scute complex homolog 1 or Ascl1) and/or distal-less homeobox 2 (Dlx2) for generation of glutamatergic or GABAergic neurons, respectively (7-21 d for different degrees of maturity). Our protocol of astroglia-to-neuron conversion by a single neurogenic transcription factor provides a stringent experimental system to study the specification of a selective neuronal subtype, thus offering an alternative to the use of embryonic or neural stem cells. Moreover, it can be a useful model for studies of lineage conversion from non-neuronal cells, with potential for brain regenerative medicine.
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