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mTORC2 Loss in Oligodendrocyte Progenitor Cells Results in Regional Hypomyelination in the Central Nervous System. J Neurosci 2023; 43:540-558. [PMID: 36460463 PMCID: PMC9888514 DOI: 10.1523/jneurosci.0010-22.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 11/02/2022] [Accepted: 11/24/2022] [Indexed: 12/03/2022] Open
Abstract
In the CNS, oligodendrocyte progenitor cells (OPCs) differentiate into mature oligodendrocytes to generate myelin, an essential component for normal nervous system function. OPC differentiation is driven by signaling pathways, such as mTOR, which functions in two distinct complexes: mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2), containing Raptor or Rictor, respectively. In the current studies, mTORC2 signaling was selectively deleted from OPCs in PDGFRα-Cre X Rictorfl/fl mice. This study examined developmental myelination in male and female mice, comparing the impact of mTORC2 deletion in the corpus callosum and spinal cord. In both regions, Rictor loss in OPCs resulted in early reduction in myelin RNAs and proteins. However, these deficits rapidly recovered in spinal cord, where normal myelin was noted at P21 and P45. By contrast, the losses in corpus callosum resulted in severe hypomyelination and increased unmyelinated axons. The hypomyelination may result from decreased oligodendrocytes in the corpus callosum, which persisted in animals as old as postnatal day 350. The current studies focus on uniquely altered signaling pathways following mTORC2 loss in developing oligodendrocytes. A major mTORC2 substrate is phospho-Akt-S473, which was significantly reduced throughout development in both corpus callosum and spinal cord at all ages measured, yet this had little impact in spinal cord. Loss of mTORC2 signaling resulted in decreased expression of actin regulators, such as gelsolin in corpus callosum, but only minimal loss in spinal cord. The current study establishes a regionally specific role for mTORC2 signaling in OPCs, particularly in the corpus callosum.SIGNIFICANCE STATEMENT mTORC1 and mTORC2 signaling has differential impact on myelination in the CNS. Numerous studies identify a role for mTORC1, but deletion of Rictor (mTORC2 signaling) in late-stage oligodendrocytes had little impact on myelination in the CNS. However, the current studies establish that deletion of mTORC2 signaling from oligodendrocyte progenitor cells results in reduced myelination of brain axons. These studies also establish a regional impact of mTORC2, with little change in spinal cord in these conditional Rictor deletion mice. Importantly, in both brain and spinal cord, mTORC2 downstream signaling targets were impacted by Rictor deletion. Yet, these signaling changes had little impact on myelination in spinal cord, while they resulted in long-term alterations in myelination in brain.
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Notch1 and Notch2 collaboratively maintain radial glial cells in mouse neurogenesis. Neurosci Res 2020; 170:122-132. [PMID: 33309869 DOI: 10.1016/j.neures.2020.11.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/26/2020] [Accepted: 11/27/2020] [Indexed: 11/22/2022]
Abstract
During mammalian corticogenesis, Notch signaling is essential to maintain neural stem cells called radial glial cells (RGCs) and the cortical architecture. Because the conventional knockout of either Notch1 or Notch2 causes a neuroepithelial loss prior to neurogenesis, their functional relationship in RGCs remain elusive. Here, we investigated the impacts of single knockout of Notch1 and Notch2 genes, and their conditional double knockout (DKO) on mouse corticogenesis. We demonstrated that Notch1 single knockout affected RGC maintenance in early to mid-neurogenesis whereas Notch2 knockout caused no apparent defect. In contrast, Notch2 plays a role in the RGC maintenance as Notch1 does at the late stage. Notch1 and Notch2 DKO resulted in the complete loss of RGCs, suggesting their cooperative function. We found that Notch activity in RGCs depends on the Notch gene dosage irrespective of Notch1 or Notch2 at late neurogenic stage, and that Notch1 and Notch2 have a similar activity, most likely due to a drastic increase in Notch2 transcription. Our results revealed that Notch1 has an essential role in establishing the RGC pool during the early stage, whereas Notch1 and Notch2 subsequently exhibit a comparable function for RGC maintenance and neurogenesis in the late neurogenic period in the mouse telencephalon.
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Bhanothu V, Kondapi AK. Status of topoisomerase-2β protein in all-trans retinoic acid-treated human neuroblastoma (SK-N-SH) cells. J Cell Biochem 2018; 120:5169-5182. [PMID: 30318608 DOI: 10.1002/jcb.27793] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 09/10/2018] [Indexed: 01/23/2023]
Abstract
Of the mammalian topoisomerase (Topo)-2 isozymes (α and β), Topo-2β protein has been reported to regulate neuronal development and differentiation. However, the status of Topo-2β in all-trans retinoic acid (ATRA)-treated human neuroblastoma (SK-N-SH) cells is not understood. More information about the effects of ATRA on SK-N-SH cells is needed to reveal the role of ATRA in the regulation of Topo-2β levels and spontaneous regression of SK-N-SH cells to predict the clinical activity. This study was proposed to investigate the status and role of Topo-2β protein in ATRA-induced survival and neuronal differentiation of SK-N-SH cells. Microscopic, sodium dodecyl sulfate polyacrylamide gel electrophoresis after immunoprecipitations and Western blot analysis were used to study and compare Topo-2β protein among 10 µM ATRA-treated SK-N-SH cells and controls at different time points. The level of Topo-2β protein increased in the initial days of treatment but markedly decreased upon induction of differentiation by ATRA in later stages. Upon ATRA treatment, SK-N-SH cells stretched, exhibited neurite extensions, and acquired a neuronal phenotype. Both treated and untreated SK-N-SH cells were able to migrate, occupy the scratched area, and completely recolonized 24 hours later. These results suggest an indirect role of Topo-2β protein in regulation of genes involved in cell migration and differentiation of ATRA-treated SK-N-SH cells. This study suggests that Topo-2β may be part of activation/repression of protein complexes activated by epigenetic modifying agents, differentiating signals, and inducible locus. However, detailed studies are needed to explore the ATRA-downstream genes leading to Topo-2β regulation and regulatory proteins of neuronal differentiation.
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Affiliation(s)
- Venkanna Bhanothu
- Department of Biotechnology and Bioinformatics, SLS, University of Hyderabad, Hyderabad, India
| | - Anand Kumar Kondapi
- Department of Biotechnology and Bioinformatics, SLS, University of Hyderabad, Hyderabad, India
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4
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Naruse M, Ishizaki Y, Ikenaka K, Tanaka A, Hitoshi S. Origin of oligodendrocytes in mammalian forebrains: a revised perspective. J Physiol Sci 2016; 67:63-70. [PMID: 27573166 PMCID: PMC5368213 DOI: 10.1007/s12576-016-0479-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 08/16/2016] [Indexed: 12/11/2022]
Abstract
Oligodendrocyte precursor cells (OPCs) appear in the late embryonic brain, mature into oligodendrocytes (OLs), and form myelin in the postnatal brain. It has been proposed that early born OPCs derived from the ventral forebrain are eliminated postnatally and late-born OLs predominate in the adult mouse cortex. However, the temporal and regional niche for cortical OL generation, which persists throughout life in adult mammals, remains to be determined. Our recent study provides new insight into self-renewing and multipotent neural stem cells (NSCs). Our results, together with previous studies, suggest that NSCs at the dorsoventral boundary are uniquely specialized to produce myelin-forming OLs in the cortex during a restricted temporal window. These findings may help identify transcription factors or gene expression patterns which confer neural precursors with the characteristic ability of dorsoventral boundary NSCs to differentiate into OLs, and facilitate the development of new strategies for regenerative medicine of the damaged brain.
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Affiliation(s)
- Masae Naruse
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Japan
- Department of Molecular and Cellular Neurobiology, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Yasuki Ishizaki
- Department of Molecular and Cellular Neurobiology, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Kazuhiro Ikenaka
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Japan
| | - Aoi Tanaka
- Department of Integrative Physiology, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Seiji Hitoshi
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Japan.
- Department of Integrative Physiology, Shiga University of Medical Science, Otsu, Shiga, Japan.
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5
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Inflammation Promotes a Conversion of Astrocytes into Neural Progenitor Cells via NF-κB Activation. Mol Neurobiol 2015; 53:5041-55. [PMID: 26381429 PMCID: PMC5012156 DOI: 10.1007/s12035-015-9428-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 09/07/2015] [Indexed: 11/23/2022]
Abstract
Brain inflammation, a common feature in neurodegenerative diseases, is a complex series of events, which can be detrimental and even lead to neuronal death. Nonetheless, several studies suggest that inflammatory signals are also positively influencing neural cell proliferation, survival, migration, and differentiation. Recently, correlative studies suggested that astrocytes are able to dedifferentiate upon injury and may thereby re-acquire neural stem cell (NSC) potential. However, the mechanism underlying this dedifferentiation process upon injury remains unclear. Here, we report that during the early response of reactive gliosis, inflammation induces a conversion of mature astrocytes into neural progenitors. A TNF treatment induces the decrease of specific astrocyte markers, such as glial fibrillary acidic protein (GFAP) or genes related to glycogen metabolism, while a subset of these cells re-expresses immaturity markers, such as CD44, Musashi-1, and Oct4. Thus, TNF treatment results in the appearance of cells that exhibit a neural progenitor phenotype and are able to proliferate and differentiate into neurons and/or astrocytes. This dedifferentiation process is maintained as long as TNF is present in the culture medium. In addition, we highlight a role for Oct4 in this process, since the TNF-induced dedifferentiation can be prevented by inhibiting Oct4 expression. Our results show that activation of the NF-κB pathway through TNF plays an important role in the dedifferentiation of astrocytes via the re-expression of Oct4. These findings indicate that the first step of reactive gliosis is in fact a dedifferentiation process of resident astrocytes mediated by the NF-κB pathway.
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Hegarty SV, Sullivan AM, O'Keeffe GW. Zeb2: A multifunctional regulator of nervous system development. Prog Neurobiol 2015; 132:81-95. [PMID: 26193487 DOI: 10.1016/j.pneurobio.2015.07.001] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 07/14/2015] [Accepted: 07/15/2015] [Indexed: 12/19/2022]
Abstract
Zinc finger E-box binding homeobox (Zeb) 2 is a transcription factor, identified due its ability to bind Smad proteins, and consists of multiple functional domains which interact with a variety of transcriptional co-effectors. The complex nature of the Zeb2, both at its genetic and protein levels, underlie its multifunctional properties, with Zeb2 capable of acting individually or as part of a transcriptional complex to repress, and occasionally activate, target gene expression. This review introduces Zeb2 as an essential regulator of nervous system development. Zeb2 is expressed in the nervous system throughout its development, indicating its importance in neurogenic and gliogenic processes. Indeed, mutation of Zeb2 has dramatic neurological consequences both in animal models, and in humans with Mowat-Wilson syndrome, which results from heterozygous ZEB2 mutations. The mechanisms by which Zeb2 regulates the induction of the neuroectoderm (CNS primordium) and the neural crest (PNS primordium) are reviewed herein. We then describe how Zeb2 acts to direct the formation, delamination, migration and specification of neural crest cells. Zeb2 regulation of the development of a number of cerebral regions, including the neocortex and hippocampus, are then described. The diverse molecular mechanisms mediating Zeb2-directed development of various neuronal and glial populations are reviewed. The role of Zeb2 in spinal cord and enteric nervous system development is outlined, while its essential function in CNS myelination is also described. Finally, this review discusses how the neurodevelopmental defects of Zeb2 mutant mice delineate the developmental dysfunctions underpinning the multiple neurological defects observed in Mowat-Wilson syndrome patients.
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Affiliation(s)
- Shane V Hegarty
- Department of Anatomy & Neuroscience, University College Cork, Cork, Ireland.
| | - Aideen M Sullivan
- Department of Anatomy & Neuroscience, University College Cork, Cork, Ireland
| | - Gerard W O'Keeffe
- Department of Anatomy & Neuroscience, University College Cork, Cork, Ireland
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7
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Bergsland M, Covacu R, Perez Estrada C, Svensson M, Brundin L. Nitric Oxide-Induced Neuronal to Glial Lineage Fate-Change Depends on NRSF/REST Function in Neural Progenitor Cells. Stem Cells 2014; 32:2539-49. [DOI: 10.1002/stem.1749] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 04/25/2014] [Accepted: 04/27/2014] [Indexed: 11/07/2022]
Affiliation(s)
- Maria Bergsland
- Division of Neurology ; Department of Clinical Neuroscience, Karolinska Institutet, Karolinska University Hospital; Stockholm Sweden
- Division of Neurosurgery, Department of Clinical Neuroscience; Karolinska Institutet, Karolinska University Hospital; Stockholm Sweden
| | - Ruxandra Covacu
- Division of Neurology ; Department of Clinical Neuroscience, Karolinska Institutet, Karolinska University Hospital; Stockholm Sweden
| | - Cynthia Perez Estrada
- Division of Neurology ; Department of Clinical Neuroscience, Karolinska Institutet, Karolinska University Hospital; Stockholm Sweden
| | - Mikael Svensson
- Division of Neurosurgery, Department of Clinical Neuroscience; Karolinska Institutet, Karolinska University Hospital; Stockholm Sweden
| | - Lou Brundin
- Division of Neurology ; Department of Clinical Neuroscience, Karolinska Institutet, Karolinska University Hospital; Stockholm Sweden
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8
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Mao S, Li H, Sun Q, Zen K, Zhang CY, Li L. miR-17 regulates the proliferation and differentiation of the neural precursor cells during mouse corticogenesis. FEBS J 2014; 281:1144-58. [PMID: 24314167 DOI: 10.1111/febs.12680] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Revised: 11/08/2013] [Accepted: 12/02/2013] [Indexed: 01/28/2023]
Abstract
MicroRNAs (miRNAs) are endogenously expressed small, non-coding nucleotides that repress gene expression at the post-transcriptional level. In mammals, the developing brain contains a large, diverse group of miRNAs, which suggests that they play crucial roles in neural development. In the present study, we analyzed the miRNA expression patterns in the mouse cortex at various developmental stages. We found that miR-17 family miRNAs were highly expressed in the cortex during early developmental stages, and that their expression levels gradually decreased as the cortex developed. Further investigation revealed that the change in miR-17-5p expression occurred in the ventricular zone/sub-ventricular zone. In addition to promoting cell proliferation, miR-17-5p also influences the differentiation fate of neural precursor cells exposed to bone morphogenetic protein 2. Moreover, we show that these effects of miR-17-5p were mainly the result of regulating the bone morphogenetic protein signaling pathway by repressing expression of the bone morphogenetic protein type II receptor. Taken together, these findings suggest that miR-17 family members play a pivotal role in regulating cell activity during early development of the mouse cortex.
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Affiliation(s)
- Susu Mao
- Jiangsu Engineering Research Center for microRNA Biology and Biotechnology, State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University School of Life Sciences, China
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9
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Sun Y, Dong Z, Jin T, Ang KH, Huang M, Haston KM, Peng J, Zhong TP, Finkbeiner S, Weiss WA, Arkin MR, Jan LY, Guo S. Imaging-based chemical screening reveals activity-dependent neural differentiation of pluripotent stem cells. eLife 2013; 2:e00508. [PMID: 24040509 PMCID: PMC3771564 DOI: 10.7554/elife.00508] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 08/11/2013] [Indexed: 01/25/2023] Open
Abstract
Mammalian pluripotent stem cells (PSCs) represent an important venue for understanding basic principles regulating tissue-specific differentiation and discovering new tools that may facilitate clinical applications. Mechanisms that direct neural differentiation of PSCs involve growth factor signaling and transcription regulation. However, it is unknown whether and how electrical activity influences this process. Here we report a high throughput imaging-based screen, which uncovers that selamectin, an anti-helminthic therapeutic compound with reported activity on invertebrate glutamate-gated chloride channels, promotes neural differentiation of PSCs. We show that selamectin’s pro-neurogenic activity is mediated by γ2-containing GABAA receptors in subsets of neural rosette progenitors, accompanied by increased proneural and lineage-specific transcription factor expression and cell cycle exit. In vivo, selamectin promotes neurogenesis in developing zebrafish. Our results establish a chemical screening platform that reveals activity-dependent neural differentiation from PSCs. Compounds identified in this and future screening might prove therapeutically beneficial for treating neurodevelopmental or neurodegenerative disorders. DOI:http://dx.doi.org/10.7554/eLife.00508.001 Pluripotent stem cells have the potential to become most of the cell types that make up an organism. However, the signals that trigger these cells to turn into neurons rather than lung cells or muscle cells, for example, are not fully understood. Proteins called growth factors are known to have a role in this process, as are transcription factors, but it is not clear if other factors are also involved. In an attempt to identify additional mechanisms that could contribute to the formation of neurons, Sun et al. screened more than 2,000 small molecules for their ability to transform mouse pluripotent stem cells into neurons in cell culture. Surprisingly, they found that a compound called selamectin, which is used to treat parasitic flatworm infections, also triggered stem cells to turn into neurons. Selamectin works by blocking a particular type of ion channel in flatworms, but this ion channel is not found in vertebrates, which means that selamectin must be promoting the formation of neurons in mice via a different mechanism. Given that a drug related to selamectin is known to act on a subtype of receptors for the neurotransmitter GABA, Sun et al. wondered whether these receptors—known as GABAA receptors—might also underlie the effects of selamectin. Consistent with this idea, drugs that increased GABAA activity stimulated the formation of neurons, whereas drugs that reduced GABAA function blocked the effects of selamectin. In addition, Sun et al. showed that selamectin triggers human embryonic stem cells to become neurons, and that it also promotes the formation of new neurons in developing zebrafish in vivo. As well as revealing an additional mechanism for the formation of neurons from stem cells, the screening technique introduced by Sun et al. could help to identify further pro-neuronal molecules, which could aid the treatment of neurodevelopmental and neurodegenerative disorders. DOI:http://dx.doi.org/10.7554/eLife.00508.002
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Affiliation(s)
- Yaping Sun
- Department of Bioengineering and Therapeutic Science , University of California, San Francisco , San Francisco , United States ; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research , University of California, San Francisco , San Francisco , United States ; Programs in Human Genetics and Biological Sciences , University of California, San Francisco , San Francisco , United States
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10
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Ma QH, Xiang T, Yang ZZ, Zhang X, Taylor J, Xiao ZC. Abnormal myelination in the spinal cord of PTPα-knockout mice. Cell Adh Migr 2013; 7:370-6. [PMID: 23934023 DOI: 10.4161/cam.25652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
PTPα interacts with F3/contactin to form a membrane-spanning co-receptor complex to transduce extracellular signals to Fyn tyrosine kinase. As both F3 and Fyn regulate myelination, we investigated a role for PTPα in this process. Here, we report that both oligodendrocytes and neurons express PTPα that evenly distributes along myelinated axons of the spinal cord. The ablation of PTPα in vivo leads to early formation of transverse bands that are mainly constituted by F3 and Caspr along the axoglial interface. Notably, PTPα deficiency facilitates abnormal myelination and pronouncedly increases the number of non-landed oligodendrocyte loops at shortened paranodes in the spinal cord. Small axons, which are normally less myelinated, have thick myelin sheaths in the spinal cord of PTPα-null animals. Thus, PTPα may be involved in the formation of axoglial junctions and ensheathment in small axons during myelination of the spinal cord.
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Affiliation(s)
- Quan-Hong Ma
- The Key Laboratory of Stem Cell and Regenerative Medicine; Institute of Molecular and Clinical Medicine; Kunming Medical College; Kunming, China; Institute of Neuroscience; Soochow University; Suzhou, China
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11
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Ward NL, Lamanna JC. The neurovascular unit and its growth factors: coordinated response in the vascular and nervous systems. Neurol Res 2013; 26:870-83. [PMID: 15727271 DOI: 10.1179/016164104x3798] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The nervous and vascular systems contain many common organizational features and develop similarly in terms of anatomical patterning. During embryogenesis and in regions of the brain undergoing postnatal neurogenesis, neural stem cells and endothelial cells are found in close proximity, or within a so-called vascular niche. The similarities in patterning and proximity may reflect coordinated development based on responsiveness to similar growth factors such as vascular endothelial growth factor, semaphorin, and ephrins/Ephs: molecules involved in the development and maintenance of both the nervous and vascular systems. Despite the blatant similarities between the vascular and nervous systems, little is still known about the co-dependence and/or interactions between the two systems during development and following alterations in metabolic demand as seen during aging, exercise, and disease processes. The interactions between the two systems involving common growth factors suggest these two systems have evolved in an interconnected way.
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Affiliation(s)
- Nicole L Ward
- Department of Anatomy, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
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Gámez B, Rodriguez-Carballo E, Ventura F. BMP signaling in telencephalic neural cell specification and maturation. Front Cell Neurosci 2013; 7:87. [PMID: 23761735 PMCID: PMC3671186 DOI: 10.3389/fncel.2013.00087] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 05/21/2013] [Indexed: 12/13/2022] Open
Abstract
Bone morphogenetic proteins (BMPs) make up a family of morphogens that are critical for patterning, development, and function of the central and peripheral nervous system. Their effects on neural cells are pleiotropic and highly dynamic depending on the stage of development and the local niche. Neural cells display a broad expression profile of BMP ligands, receptors, and transducer molecules. Moreover, interactions of BMP signaling with other incoming morphogens and signaling pathways are crucial for most of these processes. The key role of BMP signaling suggests that it includes many regulatory mechanisms that restrict BMP activity both temporally and spatially. BMPs affect neural cell fate specification in a dynamic fashion. Initially they inhibit proliferation of neural precursors and promote the first steps in neuronal differentiation. Later on, BMP signaling effects switch from neuronal induction to promotion of astroglial identity and inhibition of neuronal or oligodendroglial lineage commitment. Furthermore, in postmitotic cells, BMPs regulate cell survival and death, to modulate neuronal subtype specification, promote dendritic and axonal growth and induce synapse formation and stabilization. In this review, we examine the canonical and non-canonical mechanisms of BMP signal transduction. Moreover, we focus on the specific role of BMPs in the nervous system including their ability to regulate neural stem cell proliferation, self-renewal, lineage specification, and neuronal function.
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Affiliation(s)
- Beatriz Gámez
- Departament de Ciències Fisiològiques II, Institut d'Investigació Biomèdica de Bellvitge, Universitat de Barcelona, L'Hospitalet de Llobregat Spain
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13
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Jo HS, Kang KH, Joe CO, Kim JW. Pten coordinates retinal neurogenesis by regulating Notch signalling. EMBO J 2011; 31:817-28. [PMID: 22258620 DOI: 10.1038/emboj.2011.443] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 11/08/2011] [Indexed: 11/09/2022] Open
Abstract
Development of nervous tissue is a coordinated process of neural progenitor cell (NPC) proliferation and neuronal differentiation. Intracellular signalling events that regulate the balance between NPC proliferation and neuronal differentiation, therefore, determine the size and composition of nervous tissues. Here, we demonstrate that negative regulation of phosphoinosite 3-kinase (PI3K)-Akt signalling by phosphatase tensin homologue (Pten) is essential for maintaining NPC population in mouse retina. We found that mouse retinal progenitor cells (RPCs) lacking the Pten gene complete neurogenesis earlier than their normal developmental schedule, resulting in their premature depletion in the mature retina. We further discover that Notch intracellular domain (NICD) fails to form transcription activator complex in Pten-deficient RPCs, and thereby unable to support RPC maintenance. Taken together, our results suggest that Pten plays a pivotal role in retinal neurogenesis by supporting Notch-driven RPC maintenance against neurogenic PI3K-Akt signalling.
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Affiliation(s)
- Hong Seok Jo
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
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Lopez-Coviella I, Mellott TJ, Schnitzler AC, Blusztajn JK. BMP9 protects septal neurons from axotomy-evoked loss of cholinergic phenotype. PLoS One 2011; 6:e21166. [PMID: 21695154 PMCID: PMC3113905 DOI: 10.1371/journal.pone.0021166] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Accepted: 05/21/2011] [Indexed: 11/18/2022] Open
Abstract
Background Cholinergic projection from the septum to the hippocampus is crucial for normal cognitive function and degeneration of cells and nerve fibers within the septohippocampal pathway contributes to the pathophysiology of Alzheimer's disease. Bone morphogenetic protein (BMP) 9 is a cholinergic differentiating factor during development both in vivo and in vitro. Methodology/Principal Findings To determine whether BMP9 could protect the adult cholinergic septohippocampal pathway from axotomy-evoked loss of the cholinergic phenotype, we performed unilateral fimbria-fornix transection in mice and treated them with a continuous intracerebroventricular infusion of BMP9 for six days. The number of choline acetyltransferase (CHAT)-positive cells was reduced by 50% in the medial septal nucleus ipsilateral to the lesion as compared to the intact, contralateral side, and BMP9 infusion prevented this loss in a dose-dependent manner. Moreover, BMP9 prevented most of the decline of hippocampal acetylcholine levels ipsilateral to the lesion, and markedly increased CHAT, choline transporter CHT, NGF receptors p75 (NGFR-p75) and TrkA (NTRK1), and NGF protein content in both the lesioned and unlesioned hippocampi. In addition, BMP9 infusion reduced bilaterally hippocampal levels of basic FGF (FGF2) protein. Conclusions/Significance These data indicate that BMP9 administration can prevent lesion-evoked impairment of the cholinergic septohippocampal neurons in adult mice and, by inducing NGF, establishes a trophic environment for these cells.
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Affiliation(s)
- Ignacio Lopez-Coviella
- Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Tiffany J. Mellott
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Aletta C. Schnitzler
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Jan K. Blusztajn
- Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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Abstract
Extensive literature documented that astrocytes release neurotransmitters, cytokines and other signaling molecules to modulate migration, maturation and myelin synthesis of oligodendrocytes through mechanisms primarily converging on cytosolic [Ca2+] transients. Considering the long-term effects, it is expected that astrocyte-conditioned medium is a major regulator of gene expression in oligodendrocytes even in the absence of cytosol-to-cytosol communication via astrocyte-oligodendrocyte gap junction channels. Indeed, by comparing the transcriptomes of immortalized precursor oligodendrocyte (Oli-neu) cells when cultured alone and co-cultured with non-touching astrocytes we found profound changes in the gene expression level, control and networking. Remarkably, the astrocyte proximity was more effective in remodeling the myelination (MYE) gene fabric and its control by cytokine receptor (CYR)-modulated intercellular Ca2+-signaling (ICS) transcriptomic network than the dibutyryl-cAMP (db-cAMP) treatment-induced transformation into myelin-associated glycoprotein-positive oligodendrocyte-like cells. Moreover, astrocyte proximity up-regulated 37 MYE genes and switched on another 14 MYE, 23 ICS and 4 CYR genes, enhancing the roles of the leukemia inhibitory factor receptor and connexins Cx29 and Cx47. The novel prominent gene analysis identified the enhancer of zeste homolog 2 as the most relevant MYE gene in the astrocyte proximity, notch gene homolog 1 in control and B-cell leukemia/lymphoma 2 in differentiated Oli-neu cells.
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Qureshi IA, Gokhan S, Mehler MF. REST and CoREST are transcriptional and epigenetic regulators of seminal neural fate decisions. Cell Cycle 2010; 9:4477-86. [PMID: 21088488 DOI: 10.4161/cc.9.22.13973] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Complementary transcriptional and epigenetic regulatory factors (e.g., histone and chromatin modifying enzymes and non-coding RNAs) regulate genes responsible for mediating neural stem cell maintenance and lineage restriction, neuronal and glial lineage specification, and progressive stages of lineage maturation. However, an overall understanding of the mechanisms that sense and integrate developmental signals at the genomic level and control cell type-specific gene network deployment has not emerged. REST and CoREST are central players in the transcriptional and epigenetic regulatory circuitry that is responsible for modulating neural genes, and they have been implicated in establishing cell identity and function, both within the nervous system and beyond it. Herein, we discuss the emerging context-specific roles of REST and CoREST and highlight our recent studies aimed at elucidating their neural developmental cell type- and stage-specific actions. These observations support the conclusion that REST and CoREST act as master regulators of key neural cell fate decisions.
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Affiliation(s)
- Irfan A Qureshi
- Rosyln and Leslie Goldstein Laboratory for Stem Cell Biology and Regenerative Medicine Albert Einstein College of Medicine, Bronx, NY, USA
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17
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Cochaud S, Chevrier L, Meunier AC, Brillet T, Chadéneau C, Muller JM. The vasoactive intestinal peptide-receptor system is involved in human glioblastoma cell migration. Neuropeptides 2010; 44:373-83. [PMID: 20638719 DOI: 10.1016/j.npep.2010.06.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 05/14/2010] [Accepted: 06/12/2010] [Indexed: 12/31/2022]
Abstract
Glioblastoma multiforme (GBM) is the most aggressive form of brain tumor in adults. This cancer has an infiltrative nature and the median survival of patients is about one year. Vasoactive intestinal peptide (VIP) belongs to a structurally related family of polypeptides and is a major regulatory factor in the central and peripheral nervous systems. VIP regulates proliferation of astrocytes and of numerous cancer cell lines and modulates migration in prostatic and colonic cancer cell lines. Little is known about the involvement of VIP and its receptors (VIP-receptor system) in proliferation or migration of GBM cells. The effects of VIP, PACAP and of synthetic VIP antagonists were tested in two human GBM cell lines, M059K and M059J, established from two different parts of a single tumor. In these cells, the data revealed that the VIP-receptor system did not affect proliferation but controlled cell migration. Indeed, in M059K cells which express components of the VIP receptor system, the VIP receptor antagonists and a PACAP antibody enhanced migration. The VIP receptor antagonists increased generation of typical migration-associated processes: filopodia and lamellipodia, and activation of Rac1 and Cdc42 GTPases. Reciprocally, in M059J cells which poorly express the VIP-receptor system, treatments with the agonists VIP and PACAP resulted in decreased cell migration. Furthermore, the peptides appeared to act through a subclass of binding sites displaying an uncommon very high affinity for these ligands. Taken together, these observations suggest that components of the VIP-receptor system negatively regulate cell migration, thus showing potential anti-oncogenic properties.
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Affiliation(s)
- Stéphanie Cochaud
- Institut de Physiologie et Biologie Cellulaires, Université de Poitiers, CNRS, 40 Avenue du Recteur Pineau, Poitiers F-86022, France
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18
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Mercer TR, Qureshi IA, Gokhan S, Dinger ME, Li G, Mattick JS, Mehler MF. Long noncoding RNAs in neuronal-glial fate specification and oligodendrocyte lineage maturation. BMC Neurosci 2010; 11:14. [PMID: 20137068 PMCID: PMC2829031 DOI: 10.1186/1471-2202-11-14] [Citation(s) in RCA: 323] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2009] [Accepted: 02/05/2010] [Indexed: 11/21/2022] Open
Abstract
Background Long non-protein-coding RNAs (ncRNAs) are emerging as important regulators of cellular differentiation and are widely expressed in the brain. Results Here we show that many long ncRNAs exhibit dynamic expression patterns during neuronal and oligodendrocyte (OL) lineage specification, neuronal-glial fate transitions, and progressive stages of OL lineage elaboration including myelination. Consideration of the genomic context of these dynamically regulated ncRNAs showed they were part of complex transcriptional loci that encompass key neural developmental protein-coding genes, with which they exhibit concordant expression profiles as indicated by both microarray and in situ hybridization analyses. These included ncRNAs associated with differentiation-specific nuclear subdomains such as Gomafu and Neat1, and ncRNAs associated with developmental enhancers and genes encoding important transcription factors and homeotic proteins. We also observed changes in ncRNA expression profiles in response to treatment with trichostatin A, a histone deacetylase inhibitor that prevents the progression of OL progenitors into post-mitotic OLs by altering lineage-specific gene expression programs. Conclusion This is the first report of long ncRNA expression in neuronal and glial cell differentiation and of the modulation of ncRNA expression by modification of chromatin architecture. These observations explicitly link ncRNA dynamics to neural stem cell fate decisions, specification and epigenetic reprogramming and may have important implications for understanding and treating neuropsychiatric diseases.
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Affiliation(s)
- Tim R Mercer
- Institute for Molecular Bioscience, University of Queensland, 306 Carmody Road, Brisbane, QLD 4072, Australia
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19
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Shankle WR, Hara J, Bjornsen L, Gade GF, Leport PC, Ali MB, Kim J, Raimo M, Reyes L, O'Heany T, Mena I. Omental therapy for primary progressive aphasia with tau negative histopathology: 3 year study. Neurol Res 2009; 31:766-9. [PMID: 19138468 DOI: 10.1179/174313209x382511] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVE Omentum transposition surgery (OT) applied to various neurodegenerative disorders has produced clinically significant improvement, which may be due to omentally-derived factors. To evaluate the clinical effect of left hemisphere OT in a primary progressive aphasia (PPA) patient, 3 year follow-up data were analysed. METHODS Left hemisphere OT was performed on a 68-year-old male with PPA, characterized by moderate dementia and severe expressive aphasia with relatively preserved comprehension, object recognition and visual-spatial abilities. He was longitudinally assessed with cognitive, functional, behavioral and brain HMPAO SPECT measures pre-OT, at baseline and every 3-6 months for 34 months. RESULTS All measures improved above baseline for >20 months and persisted at or above baseline for 34 months. Cortical activity increased by a maximum of 21% underneath transposed omentum and in synaptically connected areas, and persisted in >50% of the cortex for at least 12 months. Subjectively, family members observed improved verbal and non-verbal communication. CONCLUSION OT produced a sustained, beneficial treatment effect in PPA and warrants further clinical and basic research to identify explanatory factors.
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Affiliation(s)
- William R Shankle
- Fountain Valley Regional Hospital and Medical Center, Fountain Valley, CA, USA; Department of Cognitive Science, University of California at Irvine, Irvine, CA, USA; The Shankle Clinic, Irvine, CA, USA.
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The basic helix-loop-helix transcription factor olig2 is critical for reactive astrocyte proliferation after cortical injury. J Neurosci 2008; 28:10983-9. [PMID: 18945906 DOI: 10.1523/jneurosci.3545-08.2008] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The mechanisms underlying the formation of the glial scar after injury are poorly understood. In this report, we demonstrate that after cortical injury Olig2 is upregulated in reactive astrocytes coincident with proliferation of these cells. Short-term lineage tracing studies with glial subtype-restricted transgenic reporter lines indicate that Olig2-expressing cells in the astroglial but not the oligodendroglial lineage are the essential source of reactive astrocytes. In addition, cortical Olig2 ablation results in a decrease in proliferation of reactive astrocytes in response to injury. Cell-type-specific mutagenesis indicates that Olig2 ablation in GFAP+ astrocytes and their precursors rather than in neuronal or oligodendroglial cells is responsible for the reduction of reactive astrocyte proliferation. Thus, our studies suggest that Olig2 is critical for postinjury gliosis.
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Modulation of neuronal differentiation by CD40 isoforms. Biochem Biophys Res Commun 2008; 369:641-7. [PMID: 18312851 DOI: 10.1016/j.bbrc.2008.02.094] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Accepted: 02/14/2008] [Indexed: 12/25/2022]
Abstract
Neuron differentiation is a complex process involving various cell-cell interactions, and multiple signaling pathways. We showed previously that CD40 is expressed and functional on mouse and human neurons. In neurons, ligation of CD40 protects against serum withdrawal-induced injury and plays a role in survival and differentiation. CD40 deficient mice display neuron dysfunction, aberrant neuron morphologic changes, and associated gross brain abnormalities. Previous studies by Tone and colleagues suggested that five isoforms of CD40 exist with two predominant isoforms expressed in humans: signal-transducible CD40 type I and a C-terminal truncated, non-signal-transducible CD40 type II. We hypothesized that differential expression of CD40 isoform type I and type II in neurons may modulate neuron differentiation. Results show that adult wild-type, and CD40(-/-) deficient mice predominantly express CD40 type I and II isoforms. Whereas adult wild-type mice express mostly CD40 type I in cerebral tissues at relatively high levels, in age and gender-matched CD40(-/-) mice CD40 type I expression was almost completely absent; suggesting a predominance of the non-signal-transducible CD40 type II isoform. Younger, 1 day old wild-type mice displayed less CD40 type I, and more CD40 type II, as well as, greater expression of soluble CD40 (CD40L/CD40 signal inhibitor), compared with 1 month old mice. Neuron-like N2a cells express CD40 type I and type II isoforms while in an undifferentiated state, however once induced to differentiate, CD40 type I predominates. Further, differentiated N2a cells treated with CD40 ligand express high levels of neuron specific nuclear protein (NeuN); an effect reduced by anti-CD40 type I siRNA, but not by control (non-targeting) siRNA. Altogether these data suggest that CD40 isoforms may act in a temporal fashion to modulate neuron differentiation during brain development. Thus, modulation of neuronal CD40 isoforms and CD40 signaling may represent important therapeutic modalities for neurodegenerative and neurodevelopmental disorders, as well as, for enhancement of neurogenesis.
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22
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Jonakait GM. The effects of maternal inflammation on neuronal development: possible mechanisms. Int J Dev Neurosci 2007; 25:415-25. [DOI: 10.1016/j.ijdevneu.2007.08.017] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Accepted: 08/27/2007] [Indexed: 10/22/2022] Open
Affiliation(s)
- G. Miller Jonakait
- Department of Biological SciencesNew Jersey Institute of Technology195 University AvenueNewarkNJ07102United States
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23
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Shankle WR, Hara J, Bjornsen L, Gade GF, Leport PC, Ali MB, Kim J, Raimo M, Reyes L, Amen D, Rudy L, O'Heany T. Omentum transposition surgery for patients with Alzheimer's disease: a case series. Neurol Res 2007; 30:313-25. [PMID: 17767812 DOI: 10.1179/016164107x230126] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVE To examine effect of omentum transposition surgery (OT) in Alzheimer's disease (AD). METHODS Within-subjects design, also known as repeated-measures design, was used. OT was performed on six biopsy-confirmed AD patients (three to the left and right hemispheres each). Follow-up was conducted over 16-50 months. Outcome measures included the sum of the sub-scores of the clinical dementia rating scale (CDRSS), dementia severity rating scale (DSRS), mini-mental status exam (MMSE) and neuropsychiatric inventory (NPI), all normalized to 0-1.0. Outcomes were compared to baseline values and to expected decline with and without cholinesterase inhibitors therapy (ChEI). RESULTS Compared to baseline and to expected decline with ChEI, CDRSS scores were 22 and 39% less impaired at means of 14 and 25 months post-OT, and DSRS scores were 12 and 22% less impaired at means of 14 and 19 months post-OT (p<0.0001). Compared to baseline and expected course with and without ChEI, the MMSE scores of the left hemisphere OT patients were not significantly different for 11, 17 and 22 months respectively (p>0.49), while those of the right hemisphere OT patients more rapidly declined. The two patients with significant pre-operative behavioral problems markedly improved; NPI severity scores decreased by 23 (16%) and 78 (54%) points and were sustained for 22 and 42 months. DISCUSSION OT yielded cognitive, functional or behavioral improvement for up to 3.5 years in these AD patients. Compared to randomized ChEI clinical trials, OT was 34 times more likely to produce clinically significant improvement. Basic research to identify the mechanisms underlying the therapeutic effect of omentum is warranted.
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Affiliation(s)
- William R Shankle
- Fountain Valley Regional Hospital and Medical Center, Fountain Valley, CA 92708, USA.
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Mehler MF, Mattick JS. Noncoding RNAs and RNA Editing in Brain Development, Functional Diversification, and Neurological Disease. Physiol Rev 2007; 87:799-823. [PMID: 17615389 DOI: 10.1152/physrev.00036.2006] [Citation(s) in RCA: 238] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The progressive maturation and functional plasticity of the nervous system in health and disease involve a dynamic interplay between the transcriptome and the environment. There is a growing awareness that the previously unexplored molecular and functional interface mediating these complex gene-environmental interactions, particularly in brain, may encompass a sophisticated RNA regulatory network involving the twin processes of RNA editing and multifaceted actions of numerous subclasses of non-protein-coding RNAs. The mature nervous system encompasses a wide range of cell types and interconnections. Long-term changes in the strength of synaptic connections are thought to underlie memory retrieval, formation, stabilization, and effector functions. The evolving nervous system involves numerous developmental transitions, such as neurulation, neural tube patterning, neural stem cell expansion and maintenance, lineage elaboration, differentiation, axonal path finding, and synaptogenesis. Although the molecular bases for these processes are largely unknown, RNA-based epigenetic mechanisms appear to be essential for orchestrating these precise and versatile biological phenomena and in defining the etiology of a spectrum of neurological diseases. The concerted modulation of RNA editing and the selective expression of non-protein-coding RNAs during seminal as well as continuous state transitions may comprise the plastic molecular code needed to couple the intrinsic malleability of neural network connections to evolving environmental influences to establish diverse forms of short- and long-term memory, context-specific behavioral responses, and sophisticated cognitive capacities.
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Affiliation(s)
- Mark F Mehler
- Institute for Brain Disorders and Neural Regeneration, Department of Neurology, Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
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25
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Agoston DV, Szemes M, Dobi A, Palkovits M, Georgopoulos K, Gyorgy A, Ring MA. Ikaros is expressed in developing striatal neurons and involved in enkephalinergic differentiation. J Neurochem 2007; 102:1805-1816. [PMID: 17504264 DOI: 10.1111/j.1471-4159.2007.04653.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The Ikaros (Ik) gene encodes alternatively spliced zinc-finger proteins originally identified in developing hematopoietic organs and acts as master regulator of lymphoid development. During our search for transcription factors that control the developmental expression of the enkephalin (ENK) gene we found that Ik-1 and Ik-2 isoforms are specifically expressed in the embryonic striatum and bind the Ik-like cis-regulatory DNA element present on the ENK gene. Ik proteins are expressed by both proliferating (BrdU+/nestin+) and by post-mitotic differentiating (MAP2+) cells in the developing striatum between embryonic day 12 and post-natal day 2 and mRNAs encoding for the Ik and ENK genes are co-expressed by a subset of differentiating striatal neurons. Blocking the DNA binding of Ik proteins in differentiating embryonic striatal neuronal cultures resulted in decreased ENK expression and mutant animals lacking the DNA-binding domain of Ik had a deficit in the number of ENK but not in dynorphin or substance P mRNA+ cells. Animals lacking the protein interaction domain of Ik showed no deficit. These results demonstrate that Ik-1 and Ik-2 proteins through their DNA binding act as positive regulators of ENK gene expression in the developing striatum and participate in regulating enkephalinergic differentiation.
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Affiliation(s)
- Denes V Agoston
- Department of Anatomy, Physiology and Genetics, USUHS, Bethesda, Maryland, USALCB, NIMH, NIH, Bethesda, Maryland, USACutaneous Biology Research Center, MGH, Harvard Medical School, Charlestown, Massachusetts, USAGraduate Program in Genetics, The George Washington University, Washington, District of Columbia, USA
| | - Marianna Szemes
- Department of Anatomy, Physiology and Genetics, USUHS, Bethesda, Maryland, USALCB, NIMH, NIH, Bethesda, Maryland, USACutaneous Biology Research Center, MGH, Harvard Medical School, Charlestown, Massachusetts, USAGraduate Program in Genetics, The George Washington University, Washington, District of Columbia, USA
| | - Albert Dobi
- Department of Anatomy, Physiology and Genetics, USUHS, Bethesda, Maryland, USALCB, NIMH, NIH, Bethesda, Maryland, USACutaneous Biology Research Center, MGH, Harvard Medical School, Charlestown, Massachusetts, USAGraduate Program in Genetics, The George Washington University, Washington, District of Columbia, USA
| | - Miklos Palkovits
- Department of Anatomy, Physiology and Genetics, USUHS, Bethesda, Maryland, USALCB, NIMH, NIH, Bethesda, Maryland, USACutaneous Biology Research Center, MGH, Harvard Medical School, Charlestown, Massachusetts, USAGraduate Program in Genetics, The George Washington University, Washington, District of Columbia, USA
| | - Katia Georgopoulos
- Department of Anatomy, Physiology and Genetics, USUHS, Bethesda, Maryland, USALCB, NIMH, NIH, Bethesda, Maryland, USACutaneous Biology Research Center, MGH, Harvard Medical School, Charlestown, Massachusetts, USAGraduate Program in Genetics, The George Washington University, Washington, District of Columbia, USA
| | - Andrea Gyorgy
- Department of Anatomy, Physiology and Genetics, USUHS, Bethesda, Maryland, USALCB, NIMH, NIH, Bethesda, Maryland, USACutaneous Biology Research Center, MGH, Harvard Medical School, Charlestown, Massachusetts, USAGraduate Program in Genetics, The George Washington University, Washington, District of Columbia, USA
| | - Mary A Ring
- Department of Anatomy, Physiology and Genetics, USUHS, Bethesda, Maryland, USALCB, NIMH, NIH, Bethesda, Maryland, USACutaneous Biology Research Center, MGH, Harvard Medical School, Charlestown, Massachusetts, USAGraduate Program in Genetics, The George Washington University, Washington, District of Columbia, USA
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26
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Cai J, Chen Y, Cai WH, Hurlock EC, Wu H, Kernie SG, Parada LF, Lu QR. A crucial role for Olig2 in white matter astrocyte development. Development 2007; 134:1887-99. [PMID: 17428828 DOI: 10.1242/dev.02847] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The mechanisms underlying astrocyte heterogeneity in the developing mouse brain are poorly understood. The bHLH transcription factor Olig2 is essential for motoneuron and oligodendrocyte formation; however, its role in astrocyte development remains obscure. During cortical development, Olig2 is transiently expressed in immature developing astrocytes at neonatal stages and is progressively downregulated in astrocytes at late postnatal stages. To assess the function of Olig2 in astrocyte formation, we conditionally ablated Olig2 in a spatiotemporally controlled manner. In the Olig2-ablated cortex and spinal cord, the formation of astrocytes in the white matter is severely compromised. Temporally controlled mutagenesis revealed that postnatal Olig2 function is required for astrocyte differentiation in the cerebral white matter. By contrast, astrocytes in the cortical gray matter are formed, but with sustained GFAP upregulation in the superficial layers. Cell type-specific mutagenesis and fate-mapping analyses indicate that abnormal astrocyte formation is at least in part attributable to the loss of Olig2 in developing astrocytes and their precursors. Thus, our studies uncover a crucial role for Olig2 in white matter astrocyte development and reveal divergent transcriptional requirements for, and developmental sources of, morphologically and spatially distinct astrocyte subpopulations.
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Affiliation(s)
- Jeff Cai
- Department of Developmental Biology and Kent Waldrep Foundation Center for Basic Neuroscience Research on Nerve Growth and Regeneration, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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27
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Gossrau G, Thiele J, Konang R, Schmandt T, Brüstle O. Bone morphogenetic protein-mediated modulation of lineage diversification during neural differentiation of embryonic stem cells. Stem Cells 2007; 25:939-49. [PMID: 17218404 DOI: 10.1634/stemcells.2006-0299] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Embryonic stem cells (ES cells) can give rise to a broad spectrum of neural cell types. The biomedical application of ES cells will require detailed knowledge on the role of individual factors modulating fate specification during in vitro differentiation. Bone morphogenetic proteins (BMPs) are known to exert a multitude of diverse differentiation effects during embryonic development. Here, we show that exposure to BMP2 at distinct stages of neural ES cell differentiation can be used to promote specific cell lineages. During early ES cell differentiation, BMP2-mediated inhibition of neuroectodermal differentiation is associated with an increase in mesoderm and smooth muscle differentiation. In fibroblast growth factor 2-expanded ES cell-derived neural precursors, BMP2 supports the generation of neural crest phenotypes, and, within the neuronal lineage, promotes distinct subtypes of peripheral neurons, including cholinergic and autonomic phenotypes. BMP2 also exerts a density-dependent promotion of astrocyte differentiation at the expense of oligodendrocyte formation. Experiments involving inhibition of the serine threonine kinase FRAP support the notion that these effects are mediated via the JAK/STAT pathway. The preservation of diverse developmental BMP2 effects in differentiating ES cell cultures provides interesting prospects for the enrichment of distinct neural phenotypes in vitro.
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Affiliation(s)
- Gudrun Gossrau
- Institute of Reconstructive Neurobiology, Life & Brain Center, University of Bonn and Hertie Foundation, Bonn, Germany
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28
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Keilhoff G, Goihl A, Stang F, Wolf G, Fansa H. Peripheral nerve tissue engineering: autologous Schwann cells vs. transdifferentiated mesenchymal stem cells. ACTA ACUST UNITED AC 2006; 12:1451-65. [PMID: 16846343 DOI: 10.1089/ten.2006.12.1451] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Mesenchymal stem cells (MSCs) were evaluated as an alternative source for tissue engineering of peripheral nerves. MSCs, transdifferentiated MSCs, or Schwann cells cultured from male rats were grafted into devitalized autologous muscle conduits bridging a 2-cm sciatic nerve gap in female rats. The differentiation potential of MSCs and transformed cultivated MSCs into Schwann cell-like cells was exploited using a cocktail of cytokines. Polymerase chain reaction of the SRY gene confirmed the presence of the implanted cells in the grafts. After 6 weeks, regeneration was monitored clinically, histologically, and morphometrically. Autologous nerves and cell-free muscle grafts were used as control. Revascularization studies suggested that transdifferentiated MSCs, in contrast to undifferentiated MSCs, facilitated neo-angiogenesis and did not influence macrophage recruitment. Autologous nerve grafts demonstrated the best results in all regenerative parameters. An appropriate regeneration was noted in the Schwann cell-groups and, albeit with restrictions, in the transdifferentiated MSC groups, whereas regeneration in the MSC group and in the cell-free group was impaired. The results indicate that transdifferentiated MSCs implanted into devitalized muscle grafts are able to support peripheral nerve regeneration to some extent, and offer a potential for new therapeutic strategies.
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Affiliation(s)
- Gerburg Keilhoff
- Institute of Medical Neurobiology, Otto-von-Guericke-University, Magdeburg, Germany.
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29
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Abstract
Increasing evidence suggests that the development and function of the nervous system is heavily dependent on RNA editing and the intricate spatiotemporal expression of a wide repertoire of non-coding RNAs, including micro RNAs, small nucleolar RNAs and longer non-coding RNAs. Non-coding RNAs may provide the key to understanding the multi-tiered links between neural development, nervous system function, and neurological diseases.
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Affiliation(s)
- Mark F Mehler
- ARC Special Research Centre for Functional and Applied Genomics, Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD 4072, Australia
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30
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Naruse M, Nakahira E, Miyata T, Hitoshi S, Ikenaka K, Bansal R. Induction of oligodendrocyte progenitors in dorsal forebrain by intraventricular microinjection of FGF-2. Dev Biol 2006; 297:262-73. [PMID: 16782086 DOI: 10.1016/j.ydbio.2006.05.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2005] [Revised: 05/11/2006] [Accepted: 05/15/2006] [Indexed: 01/15/2023]
Abstract
During embryonic development, oligodendrocyte progenitors (OLPs) originate from the ventral forebrain under the regulation of Sonic hedgehog (Shh). Shh controls the expression of transcription factor Olig2, which is strongly implicated in OLP generation. Studies of mice deficient in Shh expression suggest, however, that an alternative pathway for OLP generation may exist. The generation of OLPs in dorsal forebrain has been suggested since treatment of dorsal-neural progenitor cells in culture with fibroblast growth factor (FGF-2) results in OLP induction. To ask if dorsal induction of OLPs in embryonic forebrain can occur in vivo and if FGF-2 could initiate an alternative pathway of regulation, we used in utero microinjection of FGF-2 into the lateral ventricles of mouse fetal forebrain. A single injection of FGF-2 at E13.5 resulted in the expression of the OLP markers Olig2 and PDGFRalpha mRNA in dorsal forebrain ventricular and intermediate zones. However, FGF-2 did not induce dorsal expression of Shh, Patched1 or Nkx2.1, and co-injection of FGF-2 and a Shh inhibitor did not attenuate the induction of Olig2 and PDGFRalpha, suggesting that Shh signaling was not involved in this FGF-2-mediated dorsal induction. These results demonstrate that the dorsal embryonic forebrain in vivo has the potential to generate OLPs in the presence of normal positional cues and that this can be driven by FGF-2 independent of Shh signaling.
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Affiliation(s)
- Masae Naruse
- Department of Physiological Sciences, School of Life Science, The Graduate University for Advanced Studies, Hayama, Miura, Kanagawa 240-0193, Japan
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Gokhan S, Marin-Husstege M, Yung SY, Fontanez D, Casaccia-Bonnefil P, Mehler MF. Combinatorial profiles of oligodendrocyte-selective classes of transcriptional regulators differentially modulate myelin basic protein gene expression. J Neurosci 2006; 25:8311-21. [PMID: 16148239 PMCID: PMC6725536 DOI: 10.1523/jneurosci.1850-05.2005] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Recent studies suggest that specific neural basic helix-loop-helix (HLH; i.e., Olig1 and Olig2, Mash1), associated inhibitory HLH (i.e., Id2 and Id4), high-mobility group domain (i.e., Sox10), and homeodomain (i.e., Nkx2.2) transcription factors are involved in oligodendrocyte (OL) lineage specification and progressive stages of maturation including myelination. However, the developmental interplay among these lineage-selective determinants, in a cell- and maturational stage-specific context, has not yet been defined. We show here in vivo and in vitro developmental expression profiles for these distinct classes of transcriptional regulators of OLs. We show that progressive stages of OL lineage maturation are characterized by dynamic changes in the subcellular distribution of these transcription factors and by different permutations of combinatorial transcriptional codes. Transient transfections of these precise combinatorial codes with a luciferase reporter gene driven by the myelin basic protein promoter define how changes in the molecular composition of these transcriptional complexes modulate myelin gene expression. Our overall findings suggest that the dynamic interplay between developmental stage-specific classes of transcriptional activators and associated inhibitory factors orchestrate myelin gene expression during terminal maturation of the mammalian CNS.
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Affiliation(s)
- Solen Gokhan
- Institute for Brain Disorders and Neural Regeneration, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Angelastro JM, Mason JL, Ignatova TN, Kukekov VG, Stengren GB, Goldman JE, Greene LA. Downregulation of activating transcription factor 5 is required for differentiation of neural progenitor cells into astrocytes. J Neurosci 2006; 25:3889-99. [PMID: 15829641 PMCID: PMC6724921 DOI: 10.1523/jneurosci.3447-04.2005] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The mechanisms that regulate neural progenitor cell differentiation are primarily unknown. The transcription factor activating transcription factor 5 (ATF5) is expressed in neural progenitors of developing brain but is absent from mature astrocytes and neurons. Here, we demonstrate that ATF5 regulates the conversion of ventricular zone (VZ) and subventricular zone (SVZ) neural progenitors into astrocytes. Constitutive ATF5 expression maintains neural progenitor cell proliferation and blocks their in vitro and in vivo differentiation into astrocytes. Conversely, loss of ATF5 function promotes cell-cycle exit and allows astrocytic differentiation in vitro and in vivo. CNTF, a promoter of astrocytic differentiation, downregulates endogenous ATF5, whereas constitutively expressed ATF5 suppresses CNTF-promoted astrocyte genesis. Unexpectedly, constitutive ATF5 expression in neonatal SVZ cells both in vitro and in vivo causes them to acquire properties and anatomic distributions of VZ cells. These findings identify ATF5 as a key regulator of astrocyte formation and potentially of the VZ to SVZ transition.
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Affiliation(s)
- James M Angelastro
- Department of Pathology and Center for Neurobiology and Behavior, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA.
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Mastronardi FG, Moscarello MA. Molecules affecting myelin stability: a novel hypothesis regarding the pathogenesis of multiple sclerosis. J Neurosci Res 2005; 80:301-8. [PMID: 15704220 DOI: 10.1002/jnr.20420] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this Mini-Review we present a new hypothesis in support of the neurodegenerative theory as a mechanism for the pathogenesis of multiple sclerosis (MS). The pathogenesis of MS results from changes in two distinct CNS compartments. These are the "myelin" and "nonmyelin" compartments. The myelin compartment is where primary demyelination, amidst attempts at remyelination, is superseded in the CNS by ongoing disease. Recent evidence obtained via magnetic resonance imaging and spectroscopy techniques supports the view that the normal-appearing white matter (NAWM) in the MS brain is altered. Several biochemical changes in NAWM have been determined. These include the cationicity of myelin basic protein (MBP) as a result of the action of peptidyl argininedeiminase (PAD) activity converting arginyl residues to citrulline. The accompanying loss of positive charge makes myelin susceptible to vesiculation and MBP more susceptible to proteolytic activity. An increase of MBP autocatalysis in the MS brain might also contribute to the generation of immunodominant epitopes. Accompanying the destruction of myelin in the myelin compartment is the activation of astrocytes and microglia. These contribute to the inflammatory response and T-cell activation leading to autoimmunity. The complex environment that exists in the demyelinating brain also affects the "nonmyelin" compartment. The inappropriate up-regulation of molecules, including those of the Jagged-1-Notch-1 signal transduction pathway, affects oligodendrocyte precursor cell (OPC) differentiation. Other effectors of oligodendrocyte maturation include stathmin, a microtubule-destabilizing protein, which prevents healing in the demyelinating brain. The hypothesis we present suggests a therapeutic strategy that should 1) target the effectors within the myelin compartment and 2) enable resident OPC maturation in the nonmyelin compartment, allowing for effective repair of myelin loss. The net effect of this new therapeutic strategy is the modification of the disease environment and the stimulation of healing and repair.
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Affiliation(s)
- Fabrizio G Mastronardi
- Structural Biochemistry and Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.
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Abstract
The discovery that the adult mammalian brain creates new neurons from pools of stemlike cells was a breakthrough in neuroscience. Interestingly, this particular new form of structural brain plasticity seems specific to discrete brain regions, and most investigations concern the subventricular zone (SVZ) and the dentate gyrus (DG) of the hippocampal formation (HF). Overall, two main lines of research have emerged over the last two decades: the first aims to understand the fundamental biological properties of neural stemlike cells (and their progeny) and the integration of the newly born neurons into preexisting networks, while the second focuses on understanding its relevance in brain functioning, which has been more extensively approached in the DG. Here, we propose an overview of the current knowledge on adult neurogenesis and its functional relevance for the adult brain. We first present an analysis of the methodological issues that have hampered progress in this field and describe the main neurogenic sites with their specificities. We will see that despite considerable progress, the levels of anatomic and functional integration of the newly born neurons within the host circuitry have yet to be elucidated. Then the intracellular mechanisms controlling neuronal fate are presented briefly, along with the extrinsic factors that regulate adult neurogenesis. We will see that a growing list of epigenetic factors that display a specificity of action depending on the neurogenic site under consideration has been identified. Finally, we review the progress accomplished in implicating neurogenesis in hippocampal functioning under physiological conditions and in the development of hippocampal-related pathologies such as epilepsy, mood disorders, and addiction. This constitutes a necessary step in promoting the development of therapeutic strategies.
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Affiliation(s)
- Djoher Nora Abrous
- Laboratoire de Physiopathologie des Comportements, Institut National de la Sané et de la Recherche Médicale, U588, Université de Bordeaux, France.
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Abstract
Since the identification of Id proteins more than a decade ago, much work has demonstrated their regulatory roles in development, cell fate and lineage determination, proliferation, differentiation, angiogenesis, invasion and migration. Recent studies reveal not only that Id protein expression is significantly correlated both with cancer progression and with overall prognosis, but also that it can be exploited as a therapeutic target. This review will focus on the recent advances in our understanding of the relationships between Id expression and cancer, as well as providing a rationale for developing therapeutic strategies using Ids as targets to treat metastatic cancers.
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Affiliation(s)
- Sylvia Fong
- California Pacific Medical Center Research Institute, San Francisco, CA 94115, USA
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Li H, Babiarz J, Woodbury J, Kane-Goldsmith N, Grumet M. Spatiotemporal heterogeneity of CNS radial glial cells and their transition to restricted precursors. Dev Biol 2004; 271:225-38. [PMID: 15223331 DOI: 10.1016/j.ydbio.2004.02.028] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2003] [Revised: 02/24/2004] [Accepted: 02/25/2004] [Indexed: 10/26/2022]
Abstract
Radial glia are among the first cells that develop in the embryonic central nervous system. They are progenitors of glia and neurons but their relationship with restricted precursors that are also derived from neuroepithelia is unclear. To clarify this issue, we analyzed expression of cell type specific markers (BLBP for radial glia, 5A5/E-NCAM for neuronal precursors and A2B5 for glial precursors) on cortical radial glia in vivo and their progeny in vitro. Clones of cortical cells initially expressing only BLBP gave rise to cells that were A2B5+ and eventually lost BLBP expression in vitro. BLBP is expressed in the rat neuroepithelium as early as E12.5 when there is little or no staining for A2B5 and 5A5. In E13.5-15.5 forebrain, A2B5 is spatially restricted co-localizing with a subset of the BLBP+ radial glia. Analysis of cells isolated acutely from embryonic cortices confirmed that BLBP expression could appear without, or together with, A2B5 or 5A5. The numbers of BLBP+/5A5+ cells decreased during neurogenesis while the numbers of BLBP+/A2B5+ cells remained high through the beginning of gliogenesis. The combined results demonstrate that spatially restricted subpopulations of radial glia along the dorsal-ventral axis acquire different markers for neuronal or glial precursors during CNS development.
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Affiliation(s)
- Hedong Li
- Department of Cell Biology and Neuroscience, and W. M. Keck Center for Collaborative Neuroscience, Rutgers, State University of New Jersey, Piscataway, NJ 08854-8082, USA
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Chen HL, Lein PJ, Wang JY, Gash D, Hoffer BJ, Chiang YH. Expression of bone morphogenetic proteins in the brain during normal aging and in 6-hydroxydopamine-lesioned animals. Brain Res 2004; 994:81-90. [PMID: 14642451 DOI: 10.1016/j.brainres.2003.09.020] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bone morphogenetic proteins (BMPs), BMP receptors (BMPRs), and endogenous BMP antagonists have been found to be critically important for the development of the central nervous system (CNS) and peripheral organs in mammals. There is also increasing evidence that this system has significant activity in the adult CNS. Accordingly, we studied the regional distribution of endogenous BMP ligand proteins, receptors, and antagonists during aging and after lesion of the midbrain dopamine pathways produced by 6-hydroxydopamine (6-OHDA). We found that there were only small changes in the levels of these molecules as a function of age. Interestingly, levels of BMP 7 and noggin, a BMP antagonist, were uniquely elevated in substantia nigra. Moreover, after lesions of the midbrain dopamine system by 6-hydroxydopamine, there was a marked reduction in levels of all BMP ligands, receptors and antagonists bilaterally in both substantia nigra and hippocampus. There were also differential changes in BMP ligands, receptors, and antagonists in the cortex and striatum after such lesions. Taken together, our results indicate significant expression of BMP-related molecules in the adult and aging brain, and suggest a dynamic and differential regulation of these molecules after perturbations.
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Affiliation(s)
- Hui-Ling Chen
- Graduate Institute of Life Sciences, National Defense Medical Center, National Defense University, Rm 270, Taipei, Taiwan
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Abstract
Both blood vessels and nerves are vital channels to and from tissues. Recent genetic insights show that they have much more in common than was originally anticipated. They use similar signals and principles to differentiate, grow and navigate towards their targets. Moreover, the vascular and nervous systems cross-talk and, when dysregulated, this contributes to medically important diseases. The realization that both systems use common genetic pathways should not only form links between vascular biology and neuroscience, but also promises to accelerate the discovery of new mechanistic insights and therapeutic opportunities.
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Affiliation(s)
- Peter Carmeliet
- Center for Transgene Technology and Gene Therapy, Flanders Interuniversity Institute for Biotechnology, Katholieke Universiteit Leuven, Campus Gasthuisberg, Herestraat 49, B-3000, Leuven, Belgium.
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Yung SY, Gokhan S, Jurcsak J, Molero AE, Abrajano JJ, Mehler MF. Differential modulation of BMP signaling promotes the elaboration of cerebral cortical GABAergic neurons or oligodendrocytes from a common sonic hedgehog-responsive ventral forebrain progenitor species. Proc Natl Acad Sci U S A 2002; 99:16273-8. [PMID: 12461181 PMCID: PMC138601 DOI: 10.1073/pnas.232586699] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
During cerebral cortical development, excitatory glutamatergic projection neurons are generated from neural stem cells intrinsic to the early embryonic cortical ventricular zone by a process of radial migration, whereas most inhibitory gamma-aminobutyric acid (GABA)ergic interneurons and oligodendrocytes (OLs) appear to be elaborated from ventral forebrain stem cells that initially undergo tangential cortical migration before terminal lineage maturation. In contrast to the more compartmentalized developmental organization of the spinal cord, the generation of neurons and OLs from a common ventral forebrain stem cell would expose these cells to the sequential actions of ventral and dorsal gradient morphogens [sonic hedgehog (Shh) and bone morphogenetic proteins (BMPs)] that normally mediate opposing developmental programs. Here we report that Shh promotes GABAergic neuronalOL lineage restriction of forebrain stem cells, in part, by activation of the basic helix-loop-helix transcription factors, Olig2 and Mash1. In mutant mice with a generalized defect in tangential cortical migration (Dlx12--), there is a profound and selective reduction in the elaboration of both cortical GABAergic neurons and OLs. Our studies further demonstrate that the sequential elaboration of cortical GABAergic neurons and OLs from common Shh-responsive ventral forebrain progenitors requires the spatial and temporal modulation of cortical BMP signaling by BMP ligands and the BMP antagonist, noggin, respectively. These findings suggest an integrative model for cerebral cortical GABAergic neuronal and OL lineage maturation that would incorporate the sequential contributions of the ventral and dorsal forebrain, and the potential role of regional developmental cues in modulating transcriptional codes within evolving neural lineage species.
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Affiliation(s)
- Shau-Yu Yung
- Departments of Neuroscience, Rose F. Kennedy Center for Research in Mental Retardation and Developmental Disabilities, Einstein Comprehensive Cancer Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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