201
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Islam MM, Zhang CL. TLX: A master regulator for neural stem cell maintenance and neurogenesis. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:210-6. [PMID: 24930777 DOI: 10.1016/j.bbagrm.2014.06.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Revised: 04/22/2014] [Accepted: 06/05/2014] [Indexed: 10/25/2022]
Abstract
The orphan nuclear receptor TLX, also known as NR2E1, is an essential regulator of neural stem cell (NSC) self-renewal, maintenance, and neurogenesis. In vertebrates, TLX is specifically localized to the neurogenic regions of the forebrain and retina throughout development and adulthood. TLX regulates the expression of genes involved in multiple pathways, such as the cell cycle, DNA replication, and cell adhesion. These roles are primarily performed through the transcriptional repression or activation of downstream target genes. Emerging evidence suggests that the misregulation of TLX might play a role in the onset and progression of human neurological disorders making this factor an ideal therapeutic target. Here, we review the current understanding of TLX function, expression, regulation, and activity significant to NSC maintenance, adult neurogenesis, and brain plasticity. This article is part of a Special Issue entitled: Nuclear receptors in animal development.
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Affiliation(s)
- Mohammed M Islam
- Department of Molecular Biology, 6000 Harry Hines Blvd., Dallas, TX 75390, USA
| | - Chun-Li Zhang
- Department of Molecular Biology, 6000 Harry Hines Blvd., Dallas, TX 75390, USA.
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202
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Guan B, Rahmanto YS, Wu RC, Wang Y, Wang Z, Wang TL, Shih IM. Roles of deletion of Arid1a, a tumor suppressor, in mouse ovarian tumorigenesis. J Natl Cancer Inst 2014; 106:dju146. [PMID: 24899687 DOI: 10.1093/jnci/dju146] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The chromatin remodeling gene, ARID1A, has been implied as a tumor suppressor, and its somatic inactivating mutations occur in a wide variety of human cancers, most frequently in ovarian and uterine endometrioid and ovarian clear cell carcinomas. Tumors with ARID1A mutations also frequently harbor PTEN or PIK3CA mutations, suggesting their collaboration in tumorigenesis. Here, we used a conditional knockout mouse model in which Arid1a and Pten were deleted either individually or in combination in the mouse ovarian surface epithelium. After 6 months, 59.1% of mice with Arid1a and Pten double knockout developed ovarian endometrioid or undifferentiated carcinoma, whereas the remaining mice showed hyperplasia of ovarian surface epithelium. In contrast, 52 mice with homozygous or heterozygous deletion in either Arid1a or Pten did not develop ovarian lesions. These results demonstrate that inactivation of Arid1a alone is insufficient for tumor initiation but it requires additional genetic alteration(s) such as Pten deletion to drive tumorigenesis.
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Affiliation(s)
- Bin Guan
- Affiliations of authors: Department of Pathology, Departments of Gynecology and Obstetrics and Oncology, Johns Hopkins University School of Medicine, Baltimore, MD (BG, YSR, RCW, YW, TLW, IMS); Department of Pathology, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan (RCW); Department of Surgery, University of Michigan, Ann Arbor, MI (ZW); Genetics Endocrinology Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD (current address for BG)
| | - Yohan Suryo Rahmanto
- Affiliations of authors: Department of Pathology, Departments of Gynecology and Obstetrics and Oncology, Johns Hopkins University School of Medicine, Baltimore, MD (BG, YSR, RCW, YW, TLW, IMS); Department of Pathology, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan (RCW); Department of Surgery, University of Michigan, Ann Arbor, MI (ZW); Genetics Endocrinology Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD (current address for BG)
| | - Ren-Chin Wu
- Affiliations of authors: Department of Pathology, Departments of Gynecology and Obstetrics and Oncology, Johns Hopkins University School of Medicine, Baltimore, MD (BG, YSR, RCW, YW, TLW, IMS); Department of Pathology, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan (RCW); Department of Surgery, University of Michigan, Ann Arbor, MI (ZW); Genetics Endocrinology Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD (current address for BG)
| | - Yihong Wang
- Affiliations of authors: Department of Pathology, Departments of Gynecology and Obstetrics and Oncology, Johns Hopkins University School of Medicine, Baltimore, MD (BG, YSR, RCW, YW, TLW, IMS); Department of Pathology, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan (RCW); Department of Surgery, University of Michigan, Ann Arbor, MI (ZW); Genetics Endocrinology Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD (current address for BG)
| | - Zhong Wang
- Affiliations of authors: Department of Pathology, Departments of Gynecology and Obstetrics and Oncology, Johns Hopkins University School of Medicine, Baltimore, MD (BG, YSR, RCW, YW, TLW, IMS); Department of Pathology, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan (RCW); Department of Surgery, University of Michigan, Ann Arbor, MI (ZW); Genetics Endocrinology Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD (current address for BG)
| | - Tian-Li Wang
- Affiliations of authors: Department of Pathology, Departments of Gynecology and Obstetrics and Oncology, Johns Hopkins University School of Medicine, Baltimore, MD (BG, YSR, RCW, YW, TLW, IMS); Department of Pathology, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan (RCW); Department of Surgery, University of Michigan, Ann Arbor, MI (ZW); Genetics Endocrinology Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD (current address for BG)
| | - Ie-Ming Shih
- Affiliations of authors: Department of Pathology, Departments of Gynecology and Obstetrics and Oncology, Johns Hopkins University School of Medicine, Baltimore, MD (BG, YSR, RCW, YW, TLW, IMS); Department of Pathology, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan (RCW); Department of Surgery, University of Michigan, Ann Arbor, MI (ZW); Genetics Endocrinology Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD (current address for BG).
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203
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Kim HJ, Ryu J, Woo HM, Cho SS, Sung MK, Kim SC, Park MH, Park T, Koo SK. Patterns of gene expression associated with Pten deficiency in the developing inner ear. PLoS One 2014; 9:e97544. [PMID: 24893171 PMCID: PMC4043736 DOI: 10.1371/journal.pone.0097544] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 04/19/2014] [Indexed: 12/26/2022] Open
Abstract
In inner ear development, phosphatase and tensin homolog (PTEN) is necessary for neuronal maintenance, such as neuronal survival and accurate nerve innervations of hair cells. We previously reported that Pten conditional knockout (cKO) mice exhibited disorganized fasciculus with neuronal apoptosis in spiral ganglion neurons (SGNs). To better understand the genes and signaling networks related to auditory neuron maintenance, we compared the profiles of differentially expressed genes (DEGs) using microarray analysis of the inner ear in E14.5 Pten cKO and wild-type mice. We identified 46 statistically significant transcripts using significance analysis of microarrays, with the false-discovery rate set at 0%. Among the DEGs, expression levels of candidate genes and expression domains were validated by quantitative real-time RT-PCR and in situ hybridization, respectively. Ingenuity pathway analysis using DEGs identified significant signaling networks associated with apoptosis, cellular movement, and axon guidance (i.e., secreted phosphoprotein 1 (Spp1)-mediated cellular movement and regulator of G-protein signaling 4 (Rgs4)-mediated axon guidance). This result was consistent with the phenotypic defects of SGNs in Pten cKO mice (e.g., neuronal apoptosis, abnormal migration, and irregular nerve fiber patterns of SGNs). From this study, we suggest two key regulatory signaling networks mediated by Spp1 and Rgs4, which may play potential roles in neuronal differentiation of developing auditory neurons.
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Affiliation(s)
- Hyung Jin Kim
- Division of Intractable Diseases, Center for Biomedical Sciences, National Institute of Health, Chungcheongbuk-do, South Korea
| | - Jihee Ryu
- Division of Intractable Diseases, Center for Biomedical Sciences, National Institute of Health, Chungcheongbuk-do, South Korea
| | - Hae-Mi Woo
- Division of Intractable Diseases, Center for Biomedical Sciences, National Institute of Health, Chungcheongbuk-do, South Korea
| | - Samuel Sunghwan Cho
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, South Korea
| | - Min Kyung Sung
- Korean BioInformation Center (KOBIC), Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Sang Cheol Kim
- Korean BioInformation Center (KOBIC), Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Mi-Hyun Park
- Division of Intractable Diseases, Center for Biomedical Sciences, National Institute of Health, Chungcheongbuk-do, South Korea
| | - Taesung Park
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, South Korea
- Department of Statistics, Seoul National University, Seoul, South Korea
| | - Soo Kyung Koo
- Division of Intractable Diseases, Center for Biomedical Sciences, National Institute of Health, Chungcheongbuk-do, South Korea
- * E-mail:
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204
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Kassai H, Sugaya Y, Noda S, Nakao K, Maeda T, Kano M, Aiba A. Selective activation of mTORC1 signaling recapitulates microcephaly, tuberous sclerosis, and neurodegenerative diseases. Cell Rep 2014; 7:1626-1639. [PMID: 24857653 DOI: 10.1016/j.celrep.2014.04.048] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 03/18/2014] [Accepted: 04/22/2014] [Indexed: 02/06/2023] Open
Abstract
Mammalian target of rapamycin (mTOR) has been implicated in human neurological diseases such as tuberous sclerosis complex (TSC), neurodegeneration, and autism. However, little is known about when and how mTOR is involved in the pathogenesis of these diseases, due to a lack of animal models that directly increase mTOR activity. Here, we generated transgenic mice expressing a gain-of-function mutant of mTOR in the forebrain in a temporally controlled manner. Selective activation of mTORC1 in embryonic stages induced cortical atrophy caused by prominent apoptosis of neuronal progenitors, associated with upregulation of HIF-1α. In striking contrast, activation of the mTORC1 pathway in adulthood resulted in cortical hypertrophy with fatal epileptic seizures, recapitulating human TSC. Activated mTORC1 in the adult cortex also promoted rapid accumulation of cytoplasmic inclusions and activation of microglial cells, indicative of progressive neurodegeneration. Our findings demonstrate that mTORC1 plays different roles in developmental and adult stages and contributes to human neurological diseases.
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Affiliation(s)
- Hidetoshi Kassai
- Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Yuki Sugaya
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Shoko Noda
- Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Kazuki Nakao
- Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan; Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
| | - Tatsuya Maeda
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo 113-0032, Japan
| | - Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Atsu Aiba
- Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan.
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205
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Metabolic requirements for the maintenance of self-renewing stem cells. Nat Rev Mol Cell Biol 2014; 15:243-56. [PMID: 24651542 DOI: 10.1038/nrm3772] [Citation(s) in RCA: 736] [Impact Index Per Article: 73.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A distinctive feature of stem cells is their capacity to self-renew to maintain pluripotency. Studies of genetically-engineered mouse models and recent advances in metabolomic analysis, particularly in haematopoietic stem cells, have deepened our understanding of the contribution made by metabolic cues to the regulation of stem cell self-renewal. Many types of stem cells heavily rely on anaerobic glycolysis, and stem cell function is also regulated by bioenergetic signalling, the AKT-mTOR pathway, Gln metabolism and fatty acid metabolism. As maintenance of a stem cell pool requires a finely-tuned balance between self-renewal and differentiation, investigations into the molecular mechanisms and metabolic pathways underlying these decisions hold great therapeutic promise.
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206
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Veleva-Rotse BO, Barnes AP. Brain patterning perturbations following PTEN loss. Front Mol Neurosci 2014; 7:35. [PMID: 24860420 PMCID: PMC4030135 DOI: 10.3389/fnmol.2014.00035] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 04/15/2014] [Indexed: 12/23/2022] Open
Abstract
This review will consider the impact of compromised PTEN signaling in brain patterning. We approach understanding the contribution of PTEN to nervous system development by surveying the findings from the numerous genetic loss-of-function models that have been generated as well as other forms of PTEN inactivation. By exploring the developmental programs influenced by this central transduction molecule, we can begin to understand the molecular mechanisms that shape the developing brain. A wealth of data indicates that PTEN plays critical roles in a variety of stages during brain development. Many of them are considered here including: stem cell proliferation, fate determination, polarity, migration, process outgrowth, myelination and somatic hypertrophy. In many of these contexts, it is clear that PTEN phosphatase activity contributes to the observed effects of genetic deletion or depletion, however recent studies have also ascribed non-catalytic functions to PTEN in regulating cell function. We also explore the potential impact this alternative pool of PTEN may have on the developing brain. Together, these elements begin to form a clearer picture of how PTEN contributes to the emergence of brain structure and binds form and function in the nervous system.
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Affiliation(s)
- Biliana O Veleva-Rotse
- Neuroscience Graduate Program, Oregon Health and Science University Portland, OR, USA ; Department of Pediatrics, Oregon Health and Science University Portland, OR, USA
| | - Anthony P Barnes
- Neuroscience Graduate Program, Oregon Health and Science University Portland, OR, USA ; Department of Pediatrics, Oregon Health and Science University Portland, OR, USA ; Department of Cell and Developmental Biology, Oregon Health and Science University Portland, OR, USA
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207
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Sun T, Hevner RF. Growth and folding of the mammalian cerebral cortex: from molecules to malformations. Nat Rev Neurosci 2014; 15:217-32. [PMID: 24646670 DOI: 10.1038/nrn3707] [Citation(s) in RCA: 340] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The size and extent of folding of the mammalian cerebral cortex are important factors that influence a species' cognitive abilities and sensorimotor skills. Studies in various animal models and in humans have provided insight into the mechanisms that regulate cortical growth and folding. Both protein-coding genes and microRNAs control cortical size, and recent progress in characterizing basal progenitor cells and the genes that regulate their proliferation has contributed to our understanding of cortical folding. Neurological disorders linked to disruptions in cortical growth and folding have been associated with novel neurogenetic mechanisms and aberrant signalling pathways, and these findings have changed concepts of brain evolution and may lead to new medical treatments for certain disorders.
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Affiliation(s)
- Tao Sun
- Department of Cell and Developmental Biology, Weill Medical College of Cornell University, 1300 York Avenue, BOX 60, New York, New York 10065, USA
| | - Robert F Hevner
- Department of Neurological Surgery and Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington 98101, USA
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208
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Guo SL, Ye H, Teng Y, Wang YL, Yang G, Li XB, Zhang C, Yang X, Yang ZZ, Yang X. Akt-p53-miR-365-cyclin D1/cdc25A axis contributes to gastric tumorigenesis induced by PTEN deficiency. Nat Commun 2014; 4:2544. [PMID: 24149576 PMCID: PMC3826643 DOI: 10.1038/ncomms3544] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 09/04/2013] [Indexed: 12/27/2022] Open
Abstract
Although PTEN/Akt signaling is frequently deregulated in human gastric cancers, the in vivo causal link between its dysregulation and gastric tumorigenesis has not been established. Here we show that inactivation of PTEN in mouse gastric epithelium initiates spontaneous carcinogenesis with complete penetrance by 2 months of age. Mechanistically, activation of Akt suppresses the abundance of p53, leading to decreased transcription of miR-365, thus causing upregulation of cyclin D1 and cdc25A, which promotes gastric cell proliferation. Importantly, genetic ablation of Akt1 restores miR-365 expression and effectively rescues gastric tumorigenesis in PTEN-mutant mice. Moreover, orthotopic restoration of miR-365 represses PTEN-deficient-induced hyperplasia. In human gastric cancer tissues, miR-365 reduction correlates with poorly differentiated histology, deep invasion and advanced stage, as well as the deregulation of PTEN, phosphorylated Akt, p53, cyclin D1 and cdc25A. These data demonstrate that the PTEN-Akt-p53-miR-365-cyclin D1/cdc25A axis serves as a new mechanism underlying gastric tumorigenesis, providing potential new therapeutic targets.
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Affiliation(s)
- Shui-Long Guo
- 1] State Key Laboratory of Proteomics, Genetic Laboratory of Development and Disease, Institute of Biotechnology, Beijing 100071, China [2] Institute of Geriatrics, PLA Postgraduate School of Medicine, PLA General Hospital, Beijing 100853, China [3]
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209
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Khaled WT, Liu P. Cancer mouse models: past, present and future. Semin Cell Dev Biol 2014; 27:54-60. [PMID: 24718321 DOI: 10.1016/j.semcdb.2014.04.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 03/29/2014] [Accepted: 04/01/2014] [Indexed: 12/26/2022]
Abstract
The development and advances in gene targeting technology over the past three decades has facilitated the generation of cancer mouse models that recapitulate features of human malignancies. These models have been and still remain instrumental in revealing the complexities of human cancer biology. However, they will need to evolve in the post-genomic era of cancer research. In this review we will highlight some of the key developments over the past decades and will discuss the new possibilities of cancer mouse models in the light of emerging powerful gene manipulating tools.
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Affiliation(s)
- Walid T Khaled
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, UK.
| | - Pentao Liu
- Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1HH, UK.
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210
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Tapias V, Greenamyre JT. A rapid and sensitive automated image-based approach for in vitro and in vivo characterization of cell morphology and quantification of cell number and neurite architecture. CURRENT PROTOCOLS IN CYTOMETRY 2014; 68:12.33.1-12.33.22. [PMID: 24692056 DOI: 10.1002/0471142956.cy1233s68] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Stereological methods for tissue cell counting, specifically for neuron quantification, decrease systematic error and sampling bias; however, they are tedious, labor intensive, and time consuming. Approaches for cell (neuron) quantification in vitro are not accurate, sensitive, or subsequently reproducible. Neuronal phenotype is related to alterations in cell morphology and neurite pattern. The techniques currently available for quantification of these features present several limitations. In this unit, we provide validated automated procedures for in vivo and in vitro quantification of cell number, morphological cell changes, and neurite morphometry in a fast, simple, and reliable manner. Our method counts up to 8 times as many neurons in less than 5% to 10% of the time required for stereological analysis (optical fractionator). In summary, this technology offers an unparalleled opportunity to examine features of cells at high resolution in a complex three-dimensional environment. These techniques provide an exceptional in vivo and in vitro system for neurotoxicity studies, disease modeling, and drug discovery.
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Affiliation(s)
- Victor Tapias
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania.,Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - J Timothy Greenamyre
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania.,Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, Pennsylvania.,Pittsburgh VA Healthcare System, Pittsburgh, Pennsylvania
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211
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Kreis P, Leondaritis G, Lieberam I, Eickholt BJ. Subcellular targeting and dynamic regulation of PTEN: implications for neuronal cells and neurological disorders. Front Mol Neurosci 2014; 7:23. [PMID: 24744697 PMCID: PMC3978343 DOI: 10.3389/fnmol.2014.00023] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 03/12/2014] [Indexed: 01/13/2023] Open
Abstract
PTEN is a lipid and protein phosphatase that regulates a diverse range of cellular mechanisms. PTEN is mainly present in the cytosol and transiently associates with the plasma membrane to dephosphorylate PI(3,4,5)P3, thereby antagonizing the PI3-Kinase signaling pathway. Recently, PTEN has been shown to associate also with organelles such as the endoplasmic reticulum (ER), the mitochondria, or the nucleus, and to be secreted outside of the cell. In addition, PTEN dynamically localizes to specialized sub-cellular compartments such as the neuronal growth cone or dendritic spines. The diverse localizations of PTEN imply a tight temporal and spatial regulation, orchestrated by mechanisms such as posttranslational modifications, formation of distinct protein–protein interactions, or the activation/recruitment of PTEN downstream of external cues. The regulation of PTEN function is thus not only important at the enzymatic activity level, but is also associated to its spatial distribution. In this review we will summarize (i) recent findings that highlight mechanisms controlling PTEN movement and sub-cellular localization, and (ii) current understanding of how PTEN localization is achieved by mechanisms controlling posttranslational modification, by association with binding partners and by PTEN structural or activity requirements. Finally, we will discuss the possible roles of compartmentalized PTEN in developing and mature neurons in health and disease.
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Affiliation(s)
- Patricia Kreis
- MRC Centre for Developmental Neurobiology, King's College London London, UK
| | - George Leondaritis
- MRC Centre for Developmental Neurobiology, King's College London London, UK ; Institute of Biochemistry, Charité - Universitätsmedizin Berlin Berlin, Germany
| | - Ivo Lieberam
- MRC Centre for Developmental Neurobiology, King's College London London, UK
| | - Britta J Eickholt
- MRC Centre for Developmental Neurobiology, King's College London London, UK ; Institute of Biochemistry, Charité - Universitätsmedizin Berlin Berlin, Germany
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212
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Gopinath SD, Webb AE, Brunet A, Rando TA. FOXO3 promotes quiescence in adult muscle stem cells during the process of self-renewal. Stem Cell Reports 2014; 2:414-26. [PMID: 24749067 PMCID: PMC3986584 DOI: 10.1016/j.stemcr.2014.02.002] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2013] [Revised: 02/08/2014] [Accepted: 02/10/2014] [Indexed: 12/19/2022] Open
Abstract
Skeletal muscle stem cells, or “satellite cells” (SCs), are required for the regeneration of damaged muscle tissue. Although SCs self-renew during regeneration, the mechanisms that govern SC re-entry into quiescence remain elusive. We show that FOXO3, a member of the forkhead family of transcription factors, is expressed in quiescent SCs (QSCs). Conditional deletion of Foxo3 in QSCs impairs self-renewal and increases the propensity of SCs to adopt a differentiated fate. Transcriptional analysis of SCs lacking FOXO3 revealed a downregulation of Notch signaling, a key regulator of SC quiescence. Conversely, overexpression of Notch intracellular domain (NICD) rescued the self-renewal deficit of FOXO3-deficient SCs. We show that FOXO3 regulates NOTCH1 and NOTCH3 receptor expression and that decreasing expression of NOTCH1 and NOTCH3 receptors phenocopies the effect of FOXO3 deficiency in SCs. We demonstrate that FOXO3, perhaps by activating Notch signaling, promotes the quiescent state during SC self-renewal in adult muscle regeneration. FOXO3 is expressed in quiescent adult SCs FOXO3 is required for self-renewal of SCs FOXO3-deficient SCs display an increased propensity to differentiate FOXO3 promotes Notch signaling, a key regulator of quiescence in adult SCs
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Affiliation(s)
- Suchitra D Gopinath
- Paul F. Glenn Laboratories for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94305, USA ; Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ashley E Webb
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Anne Brunet
- Paul F. Glenn Laboratories for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94305, USA ; Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Thomas A Rando
- Paul F. Glenn Laboratories for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94305, USA ; Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA ; Neurology Service and Rehabilitation Research and Developmental Center of Excellence, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, USA
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213
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Unique roles of estrogen-dependent Pten control in epithelial cell homeostasis of mouse vagina. Oncogene 2014; 34:1035-43. [DOI: 10.1038/onc.2014.62] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Revised: 12/24/2013] [Accepted: 01/19/2014] [Indexed: 01/01/2023]
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214
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Lasarge CL, Danzer SC. Mechanisms regulating neuronal excitability and seizure development following mTOR pathway hyperactivation. Front Mol Neurosci 2014; 7:18. [PMID: 24672426 PMCID: PMC3953715 DOI: 10.3389/fnmol.2014.00018] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 02/27/2014] [Indexed: 01/19/2023] Open
Abstract
The phosphatidylinositol-3-kinase/phosphatase and tensin homolog (PTEN)-mammalian target of rapamycin (mTOR) pathway regulates a variety of neuronal functions, including cell proliferation, survival, growth, and plasticity. Dysregulation of the pathway is implicated in the development of both genetic and acquired epilepsies. Indeed, several causal mutations have been identified in patients with epilepsy, the most prominent of these being mutations in PTEN and tuberous sclerosis complexes 1 and 2 (TSC1, TSC2). These genes act as negative regulators of mTOR signaling, and mutations lead to hyperactivation of the pathway. Animal models deleting PTEN, TSC1, and TSC2 consistently produce epilepsy phenotypes, demonstrating that increased mTOR signaling can provoke neuronal hyperexcitability. Given the broad range of changes induced by altered mTOR signaling, however, the mechanisms underlying seizure development in these animals remain uncertain. In transgenic mice, cell populations with hyperactive mTOR have many structural abnormalities that support recurrent circuit formation, including somatic and dendritic hypertrophy, aberrant basal dendrites, and enlargement of axon tracts. At the functional level, mTOR hyperactivation is commonly, but not always, associated with enhanced synaptic transmission and plasticity. Moreover, these populations of abnormal neurons can affect the larger network, inducing secondary changes that may explain paradoxical findings reported between cell and network functioning in different models or at different developmental time points. Here, we review the animal literature examining the link between mTOR hyperactivation and epileptogenesis, emphasizing the impact of enhanced mTOR signaling on neuronal form and function.
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Affiliation(s)
- Candi L Lasarge
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA
| | - Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA ; Department of Anesthesia, University of Cincinnati Cincinnati, OH, USA ; Department of Pediatrics, University of Cincinnati Cincinnati, OH, USA
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215
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Ohtake Y, Park D, Abdul-Muneer PM, Li H, Xu B, Sharma K, Smith GM, Selzer ME, Li S. The effect of systemic PTEN antagonist peptides on axon growth and functional recovery after spinal cord injury. Biomaterials 2014; 35:4610-26. [PMID: 24630093 DOI: 10.1016/j.biomaterials.2014.02.037] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Accepted: 02/20/2014] [Indexed: 10/25/2022]
Abstract
Knockout studies suggest that PTEN limits the regenerative capacities of CNS axons as a dominant antagonist of PI3 kinase, but the transgenic approach is not feasible for treating patients. Although application of bisperoxovanadium may block PTEN function, it is a general inhibitor of phosphotyrosine phosphatases and may target enzymes other than PTEN, causing side effects and preventing firm conclusions about PTEN inhibition on regulating neuronal growth. A pharmacological method to selectively suppress PTEN post-injury could be a valuable strategy for promoting CNS axon regeneration. We identified PTEN antagonist peptides (PAPs) by targeting PTEN critical functional domains and evaluated their efficacy for promoting axon growth. Four PAPs (PAP 1-4) bound to PTEN protein expressed in COS7 cells and blocked PTEN signaling in vivo. Subcutaneous administration of PAPs initiated two days after dorsal over-hemisection injury significantly stimulated growth of descending serotonergic fibers in the caudal spinal cord of adult mice. Systemic PAPs induce significant sprouting of corticospinal fibers in the rostral spinal cord and limited growth of corticospinal axons in the caudal spinal cord. More importantly, PAP treatment enhanced recovery of locomotor function in adult rodents with spinal cord injury. This study may facilitate development of effective therapeutic agents for CNS injuries.
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Affiliation(s)
- Yosuke Ohtake
- Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Dongsun Park
- Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - P M Abdul-Muneer
- Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Hui Li
- Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Bin Xu
- Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Kartavya Sharma
- Department of Neurology, UT Southwestern Medical Center, Dallas, TX 75390-8813, USA
| | - George M Smith
- Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA; Department of Neuroscience, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Michael E Selzer
- Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA; Department of Neurology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Shuxin Li
- Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA; Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA.
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216
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Garcia-Junco-Clemente P, Golshani P. PTEN: A master regulator of neuronal structure, function, and plasticity. Commun Integr Biol 2014; 7:e28358. [PMID: 24778766 PMCID: PMC3995733 DOI: 10.4161/cib.28358] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 02/25/2014] [Indexed: 11/19/2022] Open
Abstract
PTEN (phosphatase and tensin homolog on chromosome ten) is a dual protein/lipid phosphatase that dephosphorylates PIP3, thereby inhibiting the AKT/mTOR pathway. This inhibition ultimately decreases protein translation, cell proliferation and cell growth. In the central nervous system, inhibition of PTEN leads to increased stem cell proliferation, somatic, dendritic and axonal growth, accelerated spine maturation, diminished synaptic plasticity, and altered intrinsic excitability. In agreement with these findings, patients carrying single-copy inactivating mutations of PTEN suffer from autism, macrocephaly, mental retardation, and epilepsy.(1) (-) (9) Understanding the mechanisms through which PTEN modulates the structure, function, and plasticity of cortical networks is a major focus of study. Preventing and reversing the changes induced by loss of Pten in model animals will pave the way for treatments in humans.
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Affiliation(s)
| | - Peyman Golshani
- Department of Neurology; David Geffen School of Medicine at UCLA; Los Angeles, CA USA ; West Los Angeles VA Medical Center; Los Angeles, CA USA
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217
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Kleijer KTE, Schmeisser MJ, Krueger DD, Boeckers TM, Scheiffele P, Bourgeron T, Brose N, Burbach JPH. Neurobiology of autism gene products: towards pathogenesis and drug targets. Psychopharmacology (Berl) 2014; 231:1037-62. [PMID: 24419271 DOI: 10.1007/s00213-013-3403-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 12/14/2013] [Indexed: 12/22/2022]
Abstract
RATIONALE The genetic heterogeneity of autism spectrum disorders (ASDs) is enormous, and the neurobiology of proteins encoded by genes associated with ASD is very diverse. Revealing the mechanisms on which different neurobiological pathways in ASD pathogenesis converge may lead to the identification of drug targets. OBJECTIVE The main objective is firstly to outline the main molecular networks and neuronal mechanisms in which ASD gene products participate and secondly to answer the question how these converge. Finally, we aim to pinpoint drug targets within these mechanisms. METHOD Literature review of the neurobiological properties of ASD gene products with a special focus on the developmental consequences of genetic defects and the possibility to reverse these by genetic or pharmacological interventions. RESULTS The regulation of activity-dependent protein synthesis appears central in the pathogenesis of ASD. Through sequential consequences for axodendritic function, neuronal disabilities arise expressed as behavioral abnormalities and autistic symptoms in ASD patients. Several known ASD gene products have their effect on this central process by affecting protein synthesis intrinsically, e.g., through enhancing the mammalian target of rapamycin (mTOR) signal transduction pathway or through impairing synaptic function in general. These are interrelated processes and can be targeted by compounds from various directions: inhibition of protein synthesis through Lovastatin, mTOR inhibition using rapamycin, or mGluR-related modulation of synaptic activity. CONCLUSIONS ASD gene products may all feed into a central process of translational control that is important for adequate glutamatergic regulation of dendritic properties. This process can be modulated by available compounds but may also be targeted by yet unexplored routes.
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Affiliation(s)
- Kristel T E Kleijer
- Department Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3984 CG, Utrecht, The Netherlands
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218
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Yang DJ, Wang XL, Ismail A, Ashman CJ, Valori CF, Wang G, Gao S, Higginbottom A, Ince PG, Azzouz M, Xu J, Shaw PJ, Ning K. PTEN regulates AMPA receptor-mediated cell viability in iPS-derived motor neurons. Cell Death Dis 2014; 5:e1096. [PMID: 24577094 PMCID: PMC3944269 DOI: 10.1038/cddis.2014.55] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 01/19/2014] [Accepted: 01/22/2014] [Indexed: 11/09/2022]
Abstract
Excitatory transmission in the brain is commonly mediated by the α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors. In amyotrophic lateral sclerosis (ALS), AMPA receptors allow cytotoxic levels of calcium into neurons, contributing to motor neuron injury. We have previously shown that oculomotor neurons resistant to the disease process in ALS show reduced AMPA-mediated inward calcium currents compared with vulnerable spinal motor neurons. We have also shown that PTEN (phosphatase and tensin homolog deleted on chromosome 10) knockdown via siRNA promotes motor neuron survival in models of spinal muscular atrophy (SMA) and ALS. It has been reported that inhibition of PTEN attenuates the death of hippocampal neurons post injury by decreasing the effective translocation of the GluR2 subunit into the membrane. In addition, leptin can regulate AMPA receptor trafficking via PTEN inhibition. Thus, we speculate that manipulation of AMPA receptors by PTEN may represent a potential therapeutic strategy for neuroprotective intervention in ALS and other neurodegenerative disorders. To this end, the first step is to establish a fibroblast-iPS-motor neuron in vitro cell model to study AMPA receptor manipulation. Here we report that iPS-derived motor neurons from human fibroblasts express AMPA receptors. PTEN depletion decreases AMPA receptor expression and AMPA-mediated whole-cell currents, resulting in inhibition of AMPA-induced neuronal death in primary cultured and iPS-derived motor neurons. Taken together, our results imply that PTEN depletion may protect motor neurons by inhibition of excitatory transmission that represents a therapeutic strategy of potential benefit for the amelioration of excitotoxicity in ALS and other neurodegenerative disorders.
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Affiliation(s)
- D-J Yang
- East Hospital, Tongji University School of Medicine, Shanghai, China
| | - X-L Wang
- East Hospital, Tongji University School of Medicine, Shanghai, China
| | - A Ismail
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - C J Ashman
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - C F Valori
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - G Wang
- East Hospital, Tongji University School of Medicine, Shanghai, China
| | - S Gao
- East Hospital, Tongji University School of Medicine, Shanghai, China
| | - A Higginbottom
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - P G Ince
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - M Azzouz
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - J Xu
- East Hospital, Tongji University School of Medicine, Shanghai, China
| | - P J Shaw
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - K Ning
- 1] East Hospital, Tongji University School of Medicine, Shanghai, China [2] Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
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219
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Janbazian L, Karamchandani J, Das S. Mouse models of glioblastoma: lessons learned and questions to be answered. J Neurooncol 2014; 118:1-8. [PMID: 24522719 DOI: 10.1007/s11060-014-1401-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 01/31/2014] [Indexed: 12/11/2022]
Abstract
Glioblastoma is the most common primary brain tumour in adults. While many patients achieve disease remission following treatment with surgical resection, radiation therapy and chemotherapy, this remission is brief and invariably followed by tumour recurrence and progression. Recent work using mouse models of the disease, coupled with data generated by The Cancer Genome Atlas, have given us new insights into the mechanisms that underlie gliomagenesis and result in glioblastoma heterogeneity. These findings suggest that the treatment of glioblastoma will require a more nuanced understanding of their biology and the employment of targeted therapeutic approaches. In this review, we will summarize the current state of mouse modeling in glioma, with a focus on how these models may inform our understanding of this disease and its treatment.
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Affiliation(s)
- Loury Janbazian
- Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for SickKids, University of Toronto, 30 Bond St, Toronto, ON, M5B 1W8, Canada
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220
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Clipperton-Allen AE, Page DT. Pten haploinsufficient mice show broad brain overgrowth but selective impairments in autism-relevant behavioral tests. Hum Mol Genet 2014; 23:3490-505. [PMID: 24497577 DOI: 10.1093/hmg/ddu057] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Accelerated head and brain growth (macrocephaly) during development is a replicated biological finding in a subset of individuals with autism spectrum disorder (ASD). However, the relationship between brain overgrowth and the behavioral and cognitive symptoms of ASD is poorly understood. The PI3K-Akt-mTOR pathway regulates cellular growth; several genes encoding negative regulators of this pathway are ASD risk factors, including PTEN. Mutations in PTEN have been reported in individuals with ASD and macrocephaly. We report that brain overgrowth is widespread in Pten germline haploinsufficient (Pten(+/-)) mice, reflecting Pten mRNA expression in the developing brain. We then ask if broad brain overgrowth translates into general or specific effects on the development of behavior and cognition by testing Pten(+/-) mice using assays relevant to ASD and comorbidities. Deficits in social behavior were observed in both sexes. Males also showed abnormalities related to repetitive behavior and mood/anxiety. Females exhibited circadian activity and emotional learning phenotypes. Widespread brain overgrowth together with selective behavioral impairments in Pten(+/-) mice raises the possibility that most brain areas and constituent cell types adapt to an altered trajectory of growth with minimal impact on the behaviors tested in our battery; however, select areas/cell types relevant to social behavior are more vulnerable or less adaptable, thus resulting in social deficits. Probing dopaminergic neurons as a candidate vulnerable cell type, we found social behavioral impairments in mice with Pten conditionally inactivated in dopaminergic neurons that are consistent with the possibility that desynchronized growth in key cell types may contribute to ASD endophenotypes.
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Affiliation(s)
- Amy E Clipperton-Allen
- Department of Neuroscience, The Scripps Research Institute, 130 Scripps Way, Jupiter 33458, FL, USA
| | - Damon T Page
- Department of Neuroscience, The Scripps Research Institute, 130 Scripps Way, Jupiter 33458, FL, USA
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221
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Weston MC, Chen H, Swann JW. Loss of mTOR repressors Tsc1 or Pten has divergent effects on excitatory and inhibitory synaptic transmission in single hippocampal neuron cultures. Front Mol Neurosci 2014; 7:1. [PMID: 24574959 DOI: 10.3389/fnmol.2014.00001] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 01/09/2014] [Indexed: 01/23/2023] Open
Abstract
The Pten and Tsc1 genes both encode proteins that repress mechanistic target of rapamycin (mTOR) signaling. Disruption of either gene in the brain results in epilepsy and autism-like symptoms in humans and mouse models, therefore it is important to understand the molecular and physiological events that lead from gene disruption to disease phenotypes. Given the similar roles these two molecules play in the regulation of cellular growth and the overlap in the phenotypes that result from their loss, we predicted that the deletion of either the Pten or Tsc1 gene from autaptic hippocampal neurons would have similar effects on neuronal morphology and synaptic transmission. Accordingly, we found that loss of either Pten or Tsc1 caused comparable increases in soma size, dendrite length and action potential properties. However, the effects of Pten and Tsc1 loss on synaptic transmission were different. Loss of Pten lead to an increase in both excitatory and inhibitory neurotransmission, while loss of Tsc1 did not affect excitatory neurotransmission and reduced inhibitory transmission by decreasing mIPSC amplitude. Although the loss of Pten or Tsc1 both increased downstream mTORC1 signaling, phosphorylation of Akt was increased in Pten-ko and decreased in Tsc1-ko neurons, potentially accounting for the different effects on synaptic transmission. Despite the different effects at the synaptic level, our data suggest that loss of Pten or Tsc1 may both lead to an increase in the ratio of excitation to inhibition at the network level, an effect that has been proposed to underlie both epilepsy and autism.
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Affiliation(s)
- Matthew C Weston
- The Cain Foundation Laboratories, The Jan and Dan Duncan Neurological Research Institute Houston, TX, USA ; Departments of Neuroscience and Pediatrics, Baylor College of Medicine Houston, TX, USA
| | - Hongmei Chen
- The Cain Foundation Laboratories, The Jan and Dan Duncan Neurological Research Institute Houston, TX, USA ; Departments of Neuroscience and Pediatrics, Baylor College of Medicine Houston, TX, USA
| | - John W Swann
- The Cain Foundation Laboratories, The Jan and Dan Duncan Neurological Research Institute Houston, TX, USA ; Departments of Neuroscience and Pediatrics, Baylor College of Medicine Houston, TX, USA
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222
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Choi NY, Choi H, Park HH, Lee EH, Yu HJ, Lee KY, Joo Lee Y, Koh SH. Neuroprotective effects of amlodipine besylate and benidipine hydrochloride on oxidative stress-injured neural stem cells. Brain Res 2014; 1551:1-12. [PMID: 24440775 DOI: 10.1016/j.brainres.2014.01.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 12/11/2013] [Accepted: 01/07/2014] [Indexed: 12/19/2022]
Abstract
Hypertension is associated with oxidative stress. Amlodipine besylate (AB) and benidipine hydrochloride (BH), which are Ca(2+) antagonists, have been reported to reduce oxidative stress. In this study, we examined the neuroprotective effects of AB and BH on oxidative stress-injured neural stem cells (NSCs), with a focus on the phosphatidylinositol 3-kinase (PI3K) pathway and the extracellular signal-regulated kinase (ERK) pathway. After treatment with H2O2, the viability of NSCs decreased in a concentration-dependent manner; however, co-treatment with AB or BH restored the viability of H2O2-injured NSCs. H2O2 increased free radical production and apoptosis in NSCs, whereas co-treatment with AB or BH attenuated these effects. To evaluate the effects of AB or BH on the H2O2-inhibited proliferation of NSCs, we performed BrdU labeling and colony formation assays and found that NSC proliferation decreased upon H2O2 treatment but that combined treatment with AB or BH restored this proliferation. Western blot analysis showed that AB and BH increased the expression of cell survival-related proteins that were linked with the PI3K and ERK pathways but decreased the expression of cell death-related proteins. To investigate whether the PI3K and ERK pathways were directly involved in the neuroprotective effects of AB and BH on H2O2-treated NSCs, NSCs were pretreated with the PI3K inhibitor, LY294002, or the ERK inhibitor, FR180204, which significantly blocked the effects of AB and BH. Together, our results suggest that AB and BH restore the H2O2-inhibited viability and proliferation of NSCs by inhibiting oxidative stress and by activating the PI3K and ERK pathways.
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Affiliation(s)
- Na-Young Choi
- Department of Neurology, Hanyang University College of Medicine, Seoul, Republic of Korea; Department of Translational Medicine, Hanyang University Graduate School of Biomedical Science & Engineering, Seoul, Republic of Korea
| | - Hojin Choi
- Department of Neurology, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - Hyun-Hee Park
- Department of Neurology, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - Eun-Hye Lee
- Department of Neurology, Hanyang University College of Medicine, Seoul, Republic of Korea; Department of Translational Medicine, Hanyang University Graduate School of Biomedical Science & Engineering, Seoul, Republic of Korea
| | - Hyun-Jeung Yu
- Department of Neurology, Bundang Jesaeng Hospital, Gyeonggi Province, Republic of Korea
| | - Kyu-Yong Lee
- Department of Neurology, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - Young Joo Lee
- Department of Neurology, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - Seong-Ho Koh
- Department of Neurology, Hanyang University College of Medicine, Seoul, Republic of Korea; Department of Translational Medicine, Hanyang University Graduate School of Biomedical Science & Engineering, Seoul, Republic of Korea.
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223
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Dietrich J, Diamond EL, Kesari S. Glioma stem cell signaling: therapeutic opportunities and challenges. Expert Rev Anticancer Ther 2014; 10:709-22. [DOI: 10.1586/era.09.190] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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224
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Lee DY, Gutmann DH. Cancer stem cells and brain tumors: uprooting the bad seeds. Expert Rev Anticancer Ther 2014; 7:1581-90. [DOI: 10.1586/14737140.7.11.1581] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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225
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Agis-Balboa RC, Fischer A. Generating new neurons to circumvent your fears: the role of IGF signaling. Cell Mol Life Sci 2014; 71:21-42. [PMID: 23543251 PMCID: PMC11113432 DOI: 10.1007/s00018-013-1316-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 02/12/2013] [Accepted: 03/04/2013] [Indexed: 12/13/2022]
Abstract
Extinction of fear memory is a particular form of cognitive function that is of special interest because of its involvement in the treatment of anxiety and mood disorders. Based on recent literature and our previous findings (EMBO J 30(19):4071-4083, 2011), we propose a new hypothesis that implies a tight relationship among IGF signaling, adult hippocampal neurogenesis and fear extinction. Our proposed model suggests that fear extinction-induced IGF2/IGFBP7 signaling promotes the survival of neurons at 2-4 weeks old that would participate in the discrimination between the original fear memory trace and the new safety memory generated during fear extinction. This is also called "pattern separation", or the ability to distinguish similar but different cues (e.g., context). To understand the molecular mechanisms underlying fear extinction is therefore of great clinical importance.
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Affiliation(s)
- R C Agis-Balboa
- Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Grisebach Str. 5, 37077, Göttingen, Germany,
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226
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Lai TW, Zhang S, Wang YT. Excitotoxicity and stroke: identifying novel targets for neuroprotection. Prog Neurobiol 2013; 115:157-88. [PMID: 24361499 DOI: 10.1016/j.pneurobio.2013.11.006] [Citation(s) in RCA: 776] [Impact Index Per Article: 70.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 11/28/2013] [Accepted: 11/29/2013] [Indexed: 01/22/2023]
Abstract
Excitotoxicity, the specific type of neurotoxicity mediated by glutamate, may be the missing link between ischemia and neuronal death, and intervening the mechanistic steps that lead to excitotoxicity can prevent stroke damage. Interest in excitotoxicity began fifty years ago when monosodium glutamate was found to be neurotoxic. Evidence soon demonstrated that glutamate is not only the primary excitatory neurotransmitter in the adult brain, but also a critical transmitter for signaling neurons to degenerate following stroke. The finding led to a number of clinical trials that tested inhibitors of excitotoxicity in stroke patients. Glutamate exerts its function in large by activating the calcium-permeable ionotropic NMDA receptor (NMDAR), and different subpopulations of the NMDAR may generate different functional outputs, depending on the signaling proteins directly bound or indirectly coupled to its large cytoplasmic tail. Synaptic activity activates the GluN2A subunit-containing NMDAR, leading to activation of the pro-survival signaling proteins Akt, ERK, and CREB. During a brief episode of ischemia, the extracellular glutamate concentration rises abruptly, and stimulation of the GluN2B-containing NMDAR in the extrasynaptic sites triggers excitotoxic neuronal death via PTEN, cdk5, and DAPK1, which are directly bound to the NMDAR, nNOS, which is indirectly coupled to the NMDAR via PSD95, and calpain, p25, STEP, p38, JNK, and SREBP1, which are further downstream. This review aims to provide a comprehensive summary of the literature on excitotoxicity and our perspectives on how the new generation of excitotoxicity inhibitors may succeed despite the failure of the previous generation of drugs.
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Affiliation(s)
- Ted Weita Lai
- Graduate Institute of Clinical Medical Science, China Medical University, 91 Hsueh-Shih Road, 40402 Taichung, Taiwan; Translational Medicine Research Center, China Medical University Hospital, 2 Yu-De Road, 40447 Taichung, Taiwan.
| | - Shu Zhang
- Translational Medicine Research Center, China Medical University Hospital, 2 Yu-De Road, 40447 Taichung, Taiwan; Brain Research Center, University of British Columbia, 2211 Wesbrook Mall, V6T 2B5 Vancouver, Canada
| | - Yu Tian Wang
- Brain Research Center, University of British Columbia, 2211 Wesbrook Mall, V6T 2B5 Vancouver, Canada.
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227
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White AC, Khuu JK, Dang CY, Hu J, Tran KV, Liu A, Gomez S, Zhang Z, Yi R, Scumpia P, Grigorian M, Lowry WE. Stem cell quiescence acts as a tumour suppressor in squamous tumours. Nat Cell Biol 2013; 16:99-107. [PMID: 24335650 PMCID: PMC3874399 DOI: 10.1038/ncb2889] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 10/31/2013] [Indexed: 12/23/2022]
Abstract
In some organs, adult stem cells are uniquely poised to serve as cancer cells of origin. It is unclear, however, whether tumorigenesis is influenced by the activation state of the adult stem cell. Hair follicle stem cells (HFSCs) act as cancer cells of origin for cutaneous squamous cell carcinoma (SCC) and undergo defined cycles of quiescence and activation. The data presented here show that HFSCs are unable to initiate tumors during the quiescent phase of the hair cycle, indicating that the mechanisms that keep HFSCs dormant are dominant to the gain of oncogenes (Ras) or the loss of tumor suppressors (p53). Furthermore, Pten activity is necessary for quiescence based tumor suppression, as its deletion alleviates tumor suppression without affecting proliferation. These data demonstrate that stem cell quiescence is a form of tumor suppression in HFSCs, and that Pten plays a role in maintaining quiescence in the presence of tumorigenic stimuli.
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Affiliation(s)
- A C White
- 1] Department of Molecular Cell and Developmental Biology, UCLA, California 90095, USA [2] Eli and Edythe Broad Center for Regenerative Medicine, UCLA, California 90095, USA
| | - J K Khuu
- 1] Department of Molecular Cell and Developmental Biology, UCLA, California 90095, USA [2] Eli and Edythe Broad Center for Regenerative Medicine, UCLA, California 90095, USA
| | - C Y Dang
- 1] Department of Molecular Cell and Developmental Biology, UCLA, California 90095, USA [2] Eli and Edythe Broad Center for Regenerative Medicine, UCLA, California 90095, USA
| | - J Hu
- 1] Department of Molecular Cell and Developmental Biology, UCLA, California 90095, USA [2] Eli and Edythe Broad Center for Regenerative Medicine, UCLA, California 90095, USA
| | - K V Tran
- 1] Department of Molecular Cell and Developmental Biology, UCLA, California 90095, USA [2] Eli and Edythe Broad Center for Regenerative Medicine, UCLA, California 90095, USA
| | - A Liu
- 1] Department of Molecular Cell and Developmental Biology, UCLA, California 90095, USA [2] Eli and Edythe Broad Center for Regenerative Medicine, UCLA, California 90095, USA
| | - S Gomez
- 1] Department of Molecular Cell and Developmental Biology, UCLA, California 90095, USA [2] Eli and Edythe Broad Center for Regenerative Medicine, UCLA, California 90095, USA
| | - Z Zhang
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309, USA
| | - R Yi
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309, USA
| | - P Scumpia
- Department of Medicine, Division of Dermatology, David Geffen School of Medicine, UCLA, California 90095, USA
| | - M Grigorian
- 1] Department of Molecular Cell and Developmental Biology, UCLA, California 90095, USA [2] Eli and Edythe Broad Center for Regenerative Medicine, UCLA, California 90095, USA
| | - W E Lowry
- 1] Department of Molecular Cell and Developmental Biology, UCLA, California 90095, USA [2] Eli and Edythe Broad Center for Regenerative Medicine, UCLA, California 90095, USA [3] Jonsson Cancer Research Center, UCLA, California 90095, USA [4] Molecular Biology Institute, UCLA, California 90095, USA
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228
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PTEN, Longevity and Age-Related Diseases. Biomedicines 2013; 1:17-48. [PMID: 28548055 PMCID: PMC5423463 DOI: 10.3390/biomedicines1010017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 11/26/2013] [Accepted: 12/09/2013] [Indexed: 02/08/2023] Open
Abstract
Since the discovery of PTEN, this protein has been shown to be an effective suppressor of cancer and a contributor to longevity. This report will review, in depth, the associations between PTEN and other molecules, its mutations and regulations in order to present how PTEN can be used to increase longevity. This report will collect recent research of PTEN and use this to discuss PTEN’s role in caloric restriction, antioxidative defense of DNA-damage and the role it plays in suppressing tumors. The report will also discuss that variety of ways that PTEN can be compromised, through mutations, complete loss of alleles and its main antagonist, the PI3K/AKT pathway.
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Matsubara S, Ding Q, Miyazaki Y, Kuwahata T, Tsukasa K, Takao S. mTOR plays critical roles in pancreatic cancer stem cells through specific and stemness-related functions. Sci Rep 2013; 3:3230. [PMID: 24231729 PMCID: PMC3828572 DOI: 10.1038/srep03230] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 10/31/2013] [Indexed: 12/23/2022] Open
Abstract
Pancreatic cancer is characterized by near-universal mutations in KRAS. The mammalian target of rapamycin (mTOR), which functions downstream of RAS, has divergent effects on stem cells. In the present study, we investigated the significance of the mTOR pathway in maintaining the properties of pancreatic cancer stem cells. The mTOR inhibitor, rapamycin, reduced the viability of CD133+ pancreatic cancer cells and sphere formation which is an index of self-renewal of stem-like cells, indicating that the mTOR pathway functions to maintain cancer stem-like cells. Further, rapamycin had different effects on CD133+ cells compared to cyclopamine which is an inhibitor of the Hedgehog pathway. Thus, the mTOR pathway has a distinct role although both pathways maintain pancreatic cancer stem cells. Therefore, mTOR might be a promising target to eliminate pancreatic cancer stem cells.
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Affiliation(s)
- Shyuichiro Matsubara
- Cancer and Regenerative Medicine, Frontier Biomedical Science and Swine Research Center, Sakuragaoka, Kagoshima, 890-8520, Japan
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230
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The tumor suppressor p53 fine-tunes reactive oxygen species levels and neurogenesis via PI3 kinase signaling. J Neurosci 2013; 33:14318-30. [PMID: 24005285 DOI: 10.1523/jneurosci.1056-13.2013] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Mounting evidence points to a role for endogenous reactive oxygen species (ROS) in cell signaling, including in the control of cell proliferation, differentiation, and fate. However, the function of ROS and their molecular regulation in embryonic mouse neural progenitor cells (eNPCs) has not yet been clarified. Here, we describe that physiological ROS are required for appropriate timing of neurogenesis in the developing telencephalon in vivo and in cultured NPCs, and that the tumor suppressor p53 plays a key role in the regulation of ROS-dependent neurogenesis. p53 loss of function leads to elevated ROS and early neurogenesis, while restoration of p53 and antioxidant treatment partially reverse the phenotype associated with premature neurogenesis. Furthermore, we describe that the expression of a number of neurogenic and oxidative stress genes relies on p53 and that both p53 and ROS-dependent induction of neurogenesis depend on PI3 kinase/phospho-Akt signaling. Our results suggest that p53 fine-tunes endogenous ROS levels to ensure the appropriate timing of neurogenesis in eNPCs. This may also have implications for the generation of tumors of neurodevelopmental origin.
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231
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Frank SB, Miranti CK. Disruption of prostate epithelial differentiation pathways and prostate cancer development. Front Oncol 2013; 3:273. [PMID: 24199173 PMCID: PMC3813973 DOI: 10.3389/fonc.2013.00273] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 10/18/2013] [Indexed: 12/14/2022] Open
Abstract
One of the foremost problems in the prostate cancer (PCa) field is the inability to distinguish aggressive from indolent disease, which leads to difficult prognoses and thousands of unnecessary surgeries. This limitation stems from the fact that the mechanisms of tumorigenesis in the prostate are poorly understood. Some genetic alterations are commonly reported in prostate tumors, including upregulation of Myc, fusion of Ets genes to androgen-regulated promoters, and loss of Pten. However, the specific roles of these aberrations in tumor initiation and progression are poorly understood. Likewise, the cell of origin for PCa remains controversial and may be linked to the aggressive potential of the tumor. One important clue is that prostate tumors co-express basal and luminal protein markers that are restricted to their distinct cell types in normal tissue. Prostate epithelium contains layer-specific stem cells as well as rare bipotent cells, which can differentiate into basal or luminal cells. We hypothesize that the primary oncogenic cell of origin is a transient-differentiating bipotent cell. Such a cell must maintain tight temporal and spatial control of differentiation pathways, thus increasing its susceptibility for oncogenic disruption. In support of this hypothesis, many of the pathways known to be involved in prostate differentiation can be linked to genes commonly altered in PCa. In this article, we review what is known about important differentiation pathways (Myc, p38MAPK, Notch, PI3K/Pten) in the prostate and how their misregulation could lead to oncogenesis. Better understanding of normal differentiation will offer new insights into tumor initiation and may help explain the functional significance of common genetic alterations seen in PCa. Additionally, this understanding could lead to new methods for classifying prostate tumors based on their differentiation status and may aid in identifying more aggressive tumors.
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Affiliation(s)
- Sander B Frank
- Laboratory of Integrin Signaling and Tumorigenesis, Van Andel Research Institute , Grand Rapids, MI , USA ; Genetics Graduate Program, Michigan State University , East Lansing, MI , USA
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232
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Ivanov VN, Wen G, Hei TK. Sodium arsenite exposure inhibits AKT and Stat3 activation, suppresses self-renewal and induces apoptotic death of embryonic stem cells. Apoptosis 2013; 18:188-200. [PMID: 23143138 DOI: 10.1007/s10495-012-0779-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Sodium arsenite exposure at concentration >5 μM may induce embryotoxic and teratogenic effects in animal models. Long-term health effects of sodium arsenite from contaminated drinking water may result in different forms of cancer and neurological abnormalities. As cancer development processes seem to be originated in stem cells, we have chosen to examine the effects of sodium arsenite on signaling pathways and the corresponding transcription factors that regulate cell viability and self-renewal in mouse embryonic stem cells (ESC) and mouse neural stem/precursor cells. We demonstrated that the crucial signaling pathway, which was substantially suppressed by sodium arsenite exposure (4 μM) in ESC, was the PI3K-AKT pathway linked with numerous downstream targets that control cell survival and apoptosis. Furthermore, the whole core transcription factor circuitry that control self-renewal of mouse ESC (Stat3-P-Tyr705, Oct4, Sox2 and Nanog) was strongly down-regulated by sodium arsenite (4 μM) exposure. This was followed by G2/M arrest and induction of the mitochondrial apoptotic pathway that might be suppressed by caspase-9 and caspase-3 inhibitors. In contrast to mouse ESC with very low endogenous IL6, mouse neural stem/precursor cells (C17.2 clone immortalized by v-myc) with high endogenous production of IL6 exhibited a strong resistance to cytotoxic effects of sodium arsenite that could be decreased by inhibitory anti-IL6 antibody or Stat3 inhibition. In summary, our data demonstrated suppression of self-renewal and induction of apoptosis in mouse ESC by sodium arsenite exposure, which was further accelerated due to simultaneous inhibition of the protective PI3K-AKT and Stat3-dependent pathways.
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Affiliation(s)
- Vladimir N Ivanov
- Department of Radiation Oncology, Center for Radiological Research, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032, USA.
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233
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Overexpression of calcium-activated potassium channels underlies cortical dysfunction in a model of PTEN-associated autism. Proc Natl Acad Sci U S A 2013; 110:18297-302. [PMID: 24145404 DOI: 10.1073/pnas.1309207110] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
De novo phosphatase and tensin homolog on chromosome ten (PTEN) mutations are a cause of sporadic autism. How single-copy loss of PTEN alters neural function is not understood. Here we report that Pten haploinsufficiency increases the expression of small-conductance calcium-activated potassium channels. The resultant augmentation of this conductance increases the amplitude of the afterspike hyperpolarization, causing a decrease in intrinsic excitability. In vivo, this change in intrinsic excitability reduces evoked firing rates of cortical pyramidal neurons but does not alter receptive field tuning. The decreased in vivo firing rate is not associated with deficits in the dendritic integration of synaptic input or with changes in dendritic complexity. These findings identify calcium-activated potassium channelopathy as a cause of cortical dysfunction in the PTEN model of autism and provide potential molecular therapeutic targets.
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234
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Charitou P, Burgering BMT. Forkhead box(O) in control of reactive oxygen species and genomic stability to ensure healthy lifespan. Antioxid Redox Signal 2013; 19:1400-19. [PMID: 22978495 DOI: 10.1089/ars.2012.4921] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
SIGNIFICANCE Transcription factors of the Forkhead box O class (FOXOs) are associated with lifespan and play a role in age-related diseases. FOXOs, therefore, serve as a paradigm for developing an understanding as to how age-related diseases, such as cancer and diabetes interconnect with lifespan. Understanding the regulatory inputs on FOXO may reveal how changes in these regulatory signaling pathways affect disease and lifespan. RECENT ADVANCES Numerous regulators of FOXO have now been described and a clear and evolutionary conserved role has emerged for phosphoinositide-3 kinase/protein kinase B (also known as c-Akt or AKT) signaling and c-jun N-terminal kinase signaling. Analysis of FOXO function in the context of these signaling pathways has shown the importance of FOXO-mediated transcriptional regulation on cell cycle progression and other cell fates, such as cell metabolism, stress resistance, and apoptosis in mediating disease and lifespan. CRITICAL ISSUES Persistent DNA damage is also tightly linked to disease and aging; yet, data on a possible link between DNA damage and FOXO have been limited. Here, we discuss possible connections between FOXO and the DNA damage response in the context of the broader role of connecting lifespan and disease. FUTURE DIRECTIONS Understanding the role of lifespan in diseases onset may provide unique and generic possibilities to intervene in disease processes to ensure a healthy lifespan.
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Affiliation(s)
- Paraskevi Charitou
- Molecular Cancer Research, University Medical Center Utrecht , Utrecht, The Netherlands
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235
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Role of the PTEN signaling pathway in autism spectrum disorder. Neurosci Bull 2013; 29:773-8. [PMID: 24136242 DOI: 10.1007/s12264-013-1382-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Accepted: 01/21/2013] [Indexed: 10/26/2022] Open
Abstract
Autism is an etiologically heterogeneous group of neurodevelopmental disorders, diagnosed mostly by the clinical behavioral phenotypes. The concept that the tumor-related gene PTEN plays a critical role in autism spectrum disorder has emerged over the last decade. In this review, we focus on the essential role of the PTEN signaling pathway in neuronal differentiation and the formation of neural circuitry, as well as genetic mouse models with Pten manipulations. Particularly, accumulated data suggest that the effect of PTEN on neural stem-cell development contributes significantly to the pathophysiology of autism spectrum disorders.
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236
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Tesio M, Oser GM, Baccelli I, Blanco-Bose W, Wu H, Göthert JR, Kogan SC, Trumpp A. Pten loss in the bone marrow leads to G-CSF-mediated HSC mobilization. ACTA ACUST UNITED AC 2013; 210:2337-49. [PMID: 24127490 PMCID: PMC3804947 DOI: 10.1084/jem.20122768] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Loss of the phosphatase and tumor suppressor gene PTEN induces G-CSF production in myeloid and stromal cells, thereby promoting HSCs mobilization from the bone marrow to the spleen and the initiation of lethal leukemia. The phosphatase and tumor suppressor PTEN inhibits the phosphoinositol-3-kinase (PI3K) signaling pathway and plays a key role in cell growth, proliferation, survival, and migration. Pten conditional deletion using MxCre or Scl-CreERT leads to splenomegaly and leukemia formation, which occurs after the relocation of normal hematopoietic stem cells (HSCs) from the bone marrow to the spleen. Unexpectedly, dormant HSCs in the bone marrow do not enter the cell cycle upon Pten loss, they do not lose self-renewal activity, and they are not exhausted. Instead, Pten deficiency causes an up-regulation of the PI3K pathway in myeloid cells, but not in HSCs. Strikingly, myeloid cells secrete high levels of G-CSF upon Pten loss, leading to the mobilization of HSCs from the bone marrow and accumulation in the spleen. After deletion of Pten in mice lacking G-CSF, the splenomegaly, myeloproliferative disease, and splenic HSC accumulation are rescued. Our data show that although PTEN has little if any role in normal HSCs, it is essential to prevent overt G-CSF production by myeloid and stromal cells which otherwise causes HSCs to relocate to the spleen followed by lethal leukemia initiation.
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Affiliation(s)
- Melania Tesio
- Deutsches Krebsforschungszentrum (DKFZ), D-69120 Heidelberg, Germany
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237
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Mukhopadhyay C, Zhao X, Maroni D, Band V, Naramura M. Distinct effects of EGFR ligands on human mammary epithelial cell differentiation. PLoS One 2013; 8:e75907. [PMID: 24124521 PMCID: PMC3790811 DOI: 10.1371/journal.pone.0075907] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 08/16/2013] [Indexed: 11/18/2022] Open
Abstract
Based on gene expression patterns, breast cancers can be divided into subtypes that closely resemble various developmental stages of normal mammary epithelial cells (MECs). Thus, understanding molecular mechanisms of MEC development is expected to provide critical insights into initiation and progression of breast cancer. Epidermal growth factor receptor (EGFR) and its ligands play essential roles in normal and pathological mammary gland. Signals through EGFR is required for normal mammary gland development. Ligands for EGFR are over-expressed in a significant proportion of breast cancers, and elevated expression of EGFR is associated with poorer clinical outcome. In the present study, we examined the effect of signals through EGFR on MEC differentiation using the human telomerase reverse transcriptase (hTERT)-immortalized human stem/progenitor MECs which express cytokeratin 5 but lack cytokeratin 19 (K5+K19- hMECs). As reported previously, these cells can be induced to differentiate into luminal and myoepithelial cells under appropriate culture conditions. K5+K19- hMECs acquired distinct cell fates in response to EGFR ligands epidermal growth factor (EGF), amphiregulin (AREG) and transforming growth factor alpha (TGFα) in differentiation-promoting MEGM medium. Specifically, presence of EGF during in vitro differentiation supported development into both luminal and myoepithelial lineages, whereas cells differentiated only towards luminal lineage when EGF was replaced with AREG. In contrast, substitution with TGFα led to differentiation only into myoepithelial lineage. Chemical inhibition of the MEK-Erk pathway, but not the phosphatidylinositol 3-kinase (PI3K)-AKT pathway, interfered with K5+K19- hMEC differentiation. The present data validate the utility of the K5+K19- hMEC cells for modeling key features of human MEC differentiation. This system should be useful in studying molecular/biochemical mechanisms of human MEC differentiation.
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Affiliation(s)
- Chandrani Mukhopadhyay
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Xiangshan Zhao
- Department of Genetics, Cell Biology and Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Dulce Maroni
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Vimla Band
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- Department of Genetics, Cell Biology and Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Mayumi Naramura
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- Department of Genetics, Cell Biology and Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail:
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238
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Coordinate regulation of mature dopaminergic axon morphology by macroautophagy and the PTEN signaling pathway. PLoS Genet 2013; 9:e1003845. [PMID: 24098148 PMCID: PMC3789823 DOI: 10.1371/journal.pgen.1003845] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Accepted: 08/14/2013] [Indexed: 12/11/2022] Open
Abstract
Macroautophagy is a conserved mechanism for the bulk degradation of proteins and organelles. Pathological studies have implicated defective macroautophagy in neurodegeneration, but physiological functions of macroautophagy in adult neurons remain unclear. Here we show that Atg7, an essential macroautophagy component, regulates dopaminergic axon terminal morphology. Mature Atg7-deficient midbrain dopamine (DA) neurons harbored selectively enlarged axonal terminals. This contrasted with the phenotype of DA neurons deficient in Pten - a key negative regulator of the mTOR kinase signaling pathway and neuron size - that displayed enlarged soma but unaltered axon terminals. Surprisingly, concomitant deficiency of both Atg7 and Pten led to a dramatic enhancement of axon terminal enlargement relative to Atg7 deletion alone. Similar genetic interactions between Atg7 and Pten were observed in the context of DA turnover and DA-dependent locomotor behaviors. These data suggest a model for morphological regulation of mature dopaminergic axon terminals whereby the impact of mTOR pathway is suppressed by macroautophagy.
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239
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Knauss JL, Bian S, Sun T. Plasmid-based target protectors allow specific blockade of miRNA silencing activity in mammalian developmental systems. Front Cell Neurosci 2013; 7:163. [PMID: 24068984 PMCID: PMC3781311 DOI: 10.3389/fncel.2013.00163] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 09/04/2013] [Indexed: 01/30/2023] Open
Abstract
Over the past decade, microRNAs (miRNAs) have emerged as essential posttranscriptional regulators of gene expression. Though a great deal has been discovered about miRNA genomics, biogenesis, mechanisms, and functions, the challenge of attributing phenotypes of altered miRNA expression to specific targets still remains. Here, we apply the existing target protector concept of blocking miRNA action at a single binding site in the 3′untranslated region (3′UTR) of its target to a plasmid-based approach. We optimize and demonstrate target protector efficacy in vitro, where it blocks repression of a luciferase construct and an endogenous protein. Using the developing mouse cortex as a model, we validate that target protectors are effective in vivo, where protectors for the miR-19a binding sites in the Pten 3′UTR alter proliferation and specification of neural progenitors, phenocopying Pten ectopic expression phenotypes. Our study introduces a new tool for analyzing specific miRNA:target interactions across mammalian developmental systems, facilitating further miRNA functional discoveries.
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Affiliation(s)
- Jennifer L Knauss
- Department of Cell and Developmental Biology, Weill Medical College of Cornell University New York, NY, USA ; Weill Cornell Graduate School of Medical Sciences New York, NY, USA
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240
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Abstract
Cerebral ischemia induces neurogenesis, including proliferation and differentiation of neural progenitor cells and migration of newly generated neuroblasts. MicroRNAs (miRNAs) are small noncoding RNAs that decrease gene expression through mRNA destabilization and/or translational repression. Emerging data indicate that miRNAs have a role in mediating processes of proliferation and differentiation of adult neural progenitor cells. This article reviews recent findings on miRNA profile changes in neural progenitor cells after cerebral infarction and the contributions of miRNAs to their ischemia-induced proliferation and differentiation. We highlight interactions between the miR-124 and the miR17-92 cluster and the Notch and Sonic hedgehog signaling pathways in mediating stroke-induced neurogenesis.
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241
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Rho O, Kiguchi K, Jiang G, DiGiovanni J. Impact of mTORC1 inhibition on keratinocyte proliferation during skin tumor promotion in wild-type and BK5.AktWT mice. Mol Carcinog 2013; 53:871-82. [PMID: 24114993 DOI: 10.1002/mc.22046] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 04/03/2013] [Accepted: 04/17/2013] [Indexed: 01/22/2023]
Abstract
In this study, we examined the impact of rapamycin on mTORC1 signaling during 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced keratinocyte proliferation and skin tumor promotion in both wild-type (FVB/N) and BK5.Akt(WT) mice. TPA activated mTORC1 signaling in a time-dependent manner in cultured primary mouse keratinocytes and a mouse keratinocyte cell line. Early activation (15-30 min) of mTORC1 signaling induced by TPA was mediated in part by PKC activation, whereas later activation (2-4 h) was mediated by activation of EGFR and Akt. BK5.Akt(WT) transgenic mice, where Akt1 is overexpressed in basal epidermis, are highly sensitive to TPA-induced epidermal proliferation and two-stage skin carcinogenesis. Targeting mTORC1 with rapamycin effectively inhibited TPA-induced epidermal hyperplasia and hyperproliferation as well as tumor promotion in a dose-dependent manner in both wild-type and BK5.Akt(WT) mice. A significant expansion (∼threefold) of the label retaining cell (LRC) population per hair follicle was observed in BK5.Akt(WT) mice compared to FVB/N mice. There was also a significant increase in K15 expressing cells in the hair follicle of transgenic mice that coincided with expression of phospho-Akt, phospho-S6K, and phospho-PRAS40, suggesting an important role of mTORC1 signaling in bulge-region keratinocyte stem cell (KSC) homeostasis. After 2 weeks of TPA treatment, LRCs had moved upward into the interfollicular epidermis from the bulge region of both wild-type and BK5.Akt(WT) mice. TPA-mediated LRC proliferation and migration was significantly inhibited by rapamycin. Collectively, the current data indicate that signaling through mTORC1 contributes significantly to the process of skin tumor promotion through effects on proliferation of the target cells for tumor development.
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Affiliation(s)
- Okkyung Rho
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, Austin, Texas
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242
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Farhy C, Elgart M, Shapira Z, Oron-Karni V, Yaron O, Menuchin Y, Rechavi G, Ashery-Padan R. Pax6 is required for normal cell-cycle exit and the differentiation kinetics of retinal progenitor cells. PLoS One 2013; 8:e76489. [PMID: 24073291 PMCID: PMC3779171 DOI: 10.1371/journal.pone.0076489] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 08/27/2013] [Indexed: 11/19/2022] Open
Abstract
The coupling between cell-cycle exit and onset of differentiation is a common feature throughout the developing nervous system, but the mechanisms that link these processes are mostly unknown. Although the transcription factor Pax6 has been implicated in both proliferation and differentiation of multiple regions within the central nervous system (CNS), its contribution to the transition between these successive states remains elusive. To gain insight into the role of Pax6 during the transition from proliferating progenitors to differentiating precursors, we investigated cell-cycle and transcriptomic changes occurring in Pax6 (-) retinal progenitor cells (RPCs). Our analyses revealed a unique cell-cycle phenotype of the Pax6-deficient RPCs, which included a reduced number of cells in the S phase, an increased number of cells exiting the cell cycle, and delayed differentiation kinetics of Pax6 (-) precursors. These alterations were accompanied by coexpression of factors that promote (Ccnd1, Ccnd2, Ccnd3) and inhibit (P27 (kip1) and P27 (kip2) ) the cell cycle. Further characterization of the changes in transcription profile of the Pax6-deficient RPCs revealed abrogated expression of multiple factors which are known to be involved in regulating proliferation of RPCs, including the transcription factors Vsx2, Nr2e1, Plagl1 and Hedgehog signaling. These findings provide novel insight into the molecular mechanism mediating the pleiotropic activity of Pax6 in RPCs. The results further suggest that rather than conveying a linear effect on RPCs, such as promoting their proliferation and inhibiting their differentiation, Pax6 regulates multiple transcriptional networks that function simultaneously, thereby conferring the capacity to proliferate, assume multiple cell fates and execute the differentiation program into retinal lineages.
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Affiliation(s)
- Chen Farhy
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Michael Elgart
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Zehavit Shapira
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Varda Oron-Karni
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Orly Yaron
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Yotam Menuchin
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Gideon Rechavi
- Cancer Research Center, Chaim Sheba Medical Center, Tel Hashomer and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ruth Ashery-Padan
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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243
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Abstract
Mammalian aging is associated with reduced tissue regeneration, increased degenerative disease, and cancer. Because stem cells regenerate many adult tissues and contribute to the development of cancer by accumulating mutations, age-related changes in stem cells likely contribute to age-related morbidity. Consistent with this, stem cell function declines with age in numerous tissues as a result of gate-keeping tumor suppressor expression, DNA damage, changes in cellular physiology, and environmental changes in tissues. It remains unknown whether declines in stem cell function during aging influence organismal longevity. However, mechanisms that influence longevity also modulate age-related morbidity, partly through effects on stem cells.
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Affiliation(s)
- Robert A J Signer
- Children's Research Institute, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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244
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Mousa A, Bakhiet M. Role of cytokine signaling during nervous system development. Int J Mol Sci 2013; 14:13931-57. [PMID: 23880850 PMCID: PMC3742226 DOI: 10.3390/ijms140713931] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 06/19/2013] [Accepted: 06/25/2013] [Indexed: 01/24/2023] Open
Abstract
Cytokines are signaling proteins that were first characterized as components of the immune response, but have been found to have pleiotropic effects in diverse aspects of body function in health and disease. They are secreted by numerous cells and are used extensively in intercellular communications to produce different activities, including intricate processes engaged in the ontogenetic development of the brain. This review discusses factors involved in brain growth regulation and recent findings exploring cytokine signaling pathways during development of the central nervous system. In view of existing data suggesting roles for neurotropic cytokines in promoting brain growth and repair, these molecules and their signaling pathways might become targets for therapeutic intervention in neurodegenerative processes due to diseases, toxicity, or trauma.
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Affiliation(s)
- Alyaa Mousa
- Department of Anatomy, Faculty of Medicine, Health Sciences Centre, Kuwait University, Safat 13060, Kuwait; E-Mail:
| | - Moiz Bakhiet
- Department of Molecular Medicine, Princess Al-Jawhara Center for Genetics and Inherited Diseases, College of Medicine and Medical Sciences, Arabian Gulf University, P.O. Box 26671 Manama, Bahrain
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +973-1723-7300
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245
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Abstract
Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a tumor suppressor gene deleted or mutated in many human cancers such as glioblastoma, spinal tumors, prostate, bladder, adrenals, thyroid, breast, endometrium, and colon cancers. They result from loss of heterozygosity (LOH) for the PTEN gene on chromosome 10q23. Previous studies reported that various drugs, chemicals, and foods can up-regulate PTEN mRNA and protein expression in different cell lines, and they may be useful in the future prevention and/or treatment of these cancers. PTEN has also been observed to have prognostic significance and is gradually being accepted as an independent prognostic factor. This will help in monitoring disease progression and/or recurrence, with a view to improving treatment outcomes and reducing the associated morbidity and mortality from these cancers. Neprilysin (NEP) is a zinc-dependent metallopeptidase that cleaves and inactivates some biologically active peptides thus switching off signal transduction at the cell surface. Decreased NEP expression in many cancers has been reported. NEP can form a complex with PTEN and enhance PTEN recruitment to the plasma membrane as well as stabilize its phosphatase activity. MicroRNA-21 (miR-21) post-transcriptionally down-regulates the expression of PTEN and stimulates growth and invasion in non-small cell lung cancer (NSCLC) (lung Ca), suggesting that this may be a potential therapeutic target in the future treatment of NSCLC. PTEN is a tumor suppressor gene associated with many human cancers. This has diagnostic, therapeutic, and prognostic significance in the management of many human cancers, and may be a target for new drug development in the future.
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Affiliation(s)
- Imran Haruna Abdulkareem
- Department of Trauma and Orthopaedics Surgery, Leeds University Teaching Hospitals, Leeds, LS9 7TF West Yorkshire, UK
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246
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Yu X, Li X, Jiang G, Wang X, Chang HC, Hsu WH, Li Q. Isradipine prevents rotenone-induced intracellular calcium rise that accelerates senescence in human neuroblastoma SH-SY5Y cells. Neuroscience 2013; 246:243-53. [PMID: 23664925 DOI: 10.1016/j.neuroscience.2013.04.062] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 04/16/2013] [Accepted: 04/30/2013] [Indexed: 01/11/2023]
Abstract
Previous research demonstrated that rotenone (RT) induces neuronal injury partially by increasing intracellular Ca(2+) concentrations ([Ca(2+)]i), and inducing oxidative stress, leading to a neurodegenerative disorder. However, the mechanism of RT-induced injury remains elusive. Recent work revealed that Ca(2+) signaling is important for RT-induced senescence in human neuroblastoma SH-SY5Y cells. In the present study, we found that in SH-SY5Y cells, RT increased [Ca(2+)]i, senescence associated β-galactosidase activity, aggregation of lipofuscin, production of reactive oxygen species, G1/G0 cell cycle arrest, and activation of p53/p21 signaling proteins. In addition, RT decreased the expression of the signaling proteins for cell proliferation and survival, Cyclin-dependent kinase 2 (CDK2), cyclin D1, and Akt. Pretreatment of SH-SY5Y cells with isradipine, an L-type Ca(2+) channel blocker, or EGTA antagonized these effects of RT. These results suggested that application of isradipine might be a novel approach to prevent RT-induced neurodegenerative disorder such as Parkinson's disease.
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Affiliation(s)
- X Yu
- Key Laboratory of Xin'an Medicine, Ministry of Education, Anhui Province Key Laboratory of R&D of Chinese Medicine, Anhui University of Traditional Chinese Medicine, Hefei 230038, China
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247
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Sami A, Karsy M. Targeting the PI3K/AKT/mTOR signaling pathway in glioblastoma: novel therapeutic agents and advances in understanding. Tumour Biol 2013; 34:1991-2002. [PMID: 23625692 DOI: 10.1007/s13277-013-0800-5] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 04/08/2013] [Indexed: 02/06/2023] Open
Abstract
Glioblastoma multiforme (GBM) is a grade IV astrocytoma with a median survival of 12 months despite current multi-modal treatment options. GBM is distinguished clinicopathologically into primary and secondary subtypes. Mutations of phosphatase and tensin homolog, and subsequent upregulation of the downstream protein kinase B/mammalian target of rapamycin (mTOR) signaling pathway, are commonly seen in primary GBM and less predominantly in secondary GBM. While investigations into targeted treatments of mTOR have been attempted, feedback regulation within the mTOR signaling pathway may account for therapeutic resistance. Currently, rapamycin analogs, dual-targeted mTOR complex 1 and 2 agents as well as dual mTOR and phosphatidylinositol-3 kinase-targeted agents are being investigated experimentally and in clinical trials. This review will discuss the experimental potential of these agents in the treatment of GBM and their current stage in the GBM drug pipeline. Knowledge obtained from the application of these agents can help in understanding the pathogenesis of GBM as well as delineating subsequent treatment strategies.
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Affiliation(s)
- Arshawn Sami
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA 30329, USA
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248
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Bian S, Hong J, Li Q, Schebelle L, Pollock A, Knauss JL, Garg V, Sun T. MicroRNA cluster miR-17-92 regulates neural stem cell expansion and transition to intermediate progenitors in the developing mouse neocortex. Cell Rep 2013; 3:1398-1406. [PMID: 23623502 DOI: 10.1016/j.celrep.2013.03.037] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 03/11/2013] [Accepted: 03/22/2013] [Indexed: 12/22/2022] Open
Abstract
During development of the embryonic neocortex, tightly regulated expansion of neural stem cells (NSCs) and their transition to intermediate progenitors (IPs) are critical for normal cortical formation and function. Molecular mechanisms that regulate NSC expansion and transition remain unclear. Here, we demonstrate that the microRNA (miRNA) miR-17-92 cluster is required for maintaining proper populations of cortical radial glial cells (RGCs) and IPs through repression of Pten and Tbr2 protein. Knockout of miR-17-92 and its paralogs specifically in the developing neocortex restricts NSC proliferation, suppresses RGC expansion, and promotes transition of RGCs to IPs. Moreover, Pten and Tbr2 protectors specifically block silencing activities of endogenous miR-17-92 and control proper numbers of RGCs and IPs in vivo. Our results demonstrate a critical role for miRNAs in promoting NSC proliferation and modulating the cell-fate decision of generating distinct neural progenitors in the developing neocortex.
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Affiliation(s)
- Shan Bian
- Department of Cell and Developmental Biology, Weill Medical College of Cornell University, 1300 York Avenue, Box 60, New York, NY 10065, USA
| | - Janet Hong
- Department of Cell and Developmental Biology, Weill Medical College of Cornell University, 1300 York Avenue, Box 60, New York, NY 10065, USA
| | - Qingsong Li
- Department of Cell and Developmental Biology, Weill Medical College of Cornell University, 1300 York Avenue, Box 60, New York, NY 10065, USA.,The Second Affiliated Hospital, Harbin Medical University, Harbin, China
| | - Laura Schebelle
- Department of Cell and Developmental Biology, Weill Medical College of Cornell University, 1300 York Avenue, Box 60, New York, NY 10065, USA
| | - Andrew Pollock
- Department of Cell and Developmental Biology, Weill Medical College of Cornell University, 1300 York Avenue, Box 60, New York, NY 10065, USA
| | - Jennifer L Knauss
- Department of Cell and Developmental Biology, Weill Medical College of Cornell University, 1300 York Avenue, Box 60, New York, NY 10065, USA
| | - Vidur Garg
- Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Tao Sun
- Department of Cell and Developmental Biology, Weill Medical College of Cornell University, 1300 York Avenue, Box 60, New York, NY 10065, USA
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249
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Choi H, Park HH, Lee KY, Choi NY, Yu HJ, Lee YJ, Park J, Huh YM, Lee SH, Koh SH. Coenzyme Q10 restores amyloid beta-inhibited proliferation of neural stem cells by activating the PI3K pathway. Stem Cells Dev 2013; 22:2112-20. [PMID: 23509892 DOI: 10.1089/scd.2012.0604] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Neurogenesis in the adult brain is important for memory and learning, and the alterations in neural stem cells (NSCs) may be an important part of Alzheimer's disease pathogenesis. The phosphatidylinositol 3-kinase (PI3K) pathway has been suggested to play an important role in neuronal cell survival and is highly involved in adult neurogenesis. Recently, coenzyme Q10 (CoQ10) was found to affect the PI3K pathway. We investigated whether CoQ10 could restore amyloid β (Aβ)25-35 oligomer-inhibited proliferation of NSCs by focusing on the PI3K pathway. To evaluate the effects of CoQ10 on Aβ25-35 oligomer-inhibited proliferation of NSCs, NSCs were treated with several concentrations of CoQ10 and/or Aβ25-35 oligomers. BrdU labeling, Colony Formation Assays, and immunoreactivity of Ki-67, a marker of proliferative activity, showed that NSC proliferation decreased with Aβ25-35 oligomer treatment, but combined treatment with CoQ10 restored it. Western blotting showed that CoQ10 treatment increased the expression levels of p85α PI3K, phosphorylated Akt (Ser473), phosphorylated glycogen synthase kinase-3β (Ser9), and heat shock transcription factor, which are proteins related to the PI3K pathway in Aβ25-35 oligomers-treated NSCs. To confirm a direct role for the PI3K pathway in CoQ10-induced restoration of proliferation of NSCs inhibited by Aβ25-35 oligomers, NSCs were pretreated with a PI3K inhibitor, LY294002; the effects of CoQ10 on the proliferation of NSCs inhibited by Aβ25-35 oligomers were almost completely blocked. Together, these results suggest that CoQ10 restores Aβ25-35 oligomer-inhibited proliferation of NSCs by activating the PI3K pathway.
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Affiliation(s)
- Hojin Choi
- Department of Neurology, Hanyang University College of Medicine, Seoul, Korea
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250
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Petralia RS, Schwartz CM, Wang YX, Kawamoto EM, Mattson MP, Yao PJ. Sonic hedgehog promotes autophagy in hippocampal neurons. Biol Open 2013; 2:499-504. [PMID: 23789099 PMCID: PMC3654269 DOI: 10.1242/bio.20134275] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 03/20/2013] [Indexed: 01/07/2023] Open
Abstract
The Sonic hedgehog (Shh) signaling pathway is well known in patterning of the neural tube during embryonic development, but its emerging role in differentiated neurons is less understood. Here we report that Shh enhances autophagy in cultured hippocampal neurons. Microarray analysis reveals the upregulation of multiple autophagy-related genes in neurons in response to Shh application. Through analysis of the autophagy-marker LC3 by immunoblot analysis and immunocytochemistry, we confirm activation of the autophagy pathway in Shh-exposed neurons. Using electron microscopy, we find autophagosomes and associated structures with a wide range of morphologies in synaptic terminals of Shh-exposed neurons. Moreover, we show that Shh-triggered autophagy depends on class III Phosphatidylinositol 3-kinase complexes (PtdIns3K). These results identify a link between Shh and autophagy pathways and, importantly, provide a lead for further understanding the physiology of Shh signaling activity in neurons.
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