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Araujo BHS, Kaid C, De Souza JS, Gomes da Silva S, Goulart E, Caires LCJ, Musso CM, Torres LB, Ferrasa A, Herai R, Zatz M, Okamoto OK, Cavalheiro EA. Down Syndrome iPSC-Derived Astrocytes Impair Neuronal Synaptogenesis and the mTOR Pathway In Vitro. Mol Neurobiol 2017; 55:5962-5975. [PMID: 29128905 DOI: 10.1007/s12035-017-0818-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Accepted: 11/02/2017] [Indexed: 10/25/2022]
Abstract
Several methods have been used to study the neuropathogenesis of Down syndrome (DS), such as mouse aneuploidies, post mortem human brains, and in vitro cell culture of neural progenitor cells. More recently, induced pluripotent stem cell (iPSC) technology has offered new approaches in investigation, providing a valuable tool for studying specific cell types affected by DS, especially neurons and astrocytes. Here, we investigated the role of astrocytes in DS developmental disease and the impact of the astrocyte secretome in neuron mTOR signaling and synapse formation using iPSC derived from DS and wild-type (WT) subjects. We demonstrated for the first time that DS neurons derived from hiPSC recapitulate the hyperactivation of the Akt/mTOR axis observed in DS brains and that DS astrocytes may play a key role in this dysfunction. Our results bear out that 21 trisomy in astrocytes contributes to neuronal abnormalities in addition to cell autonomous dysfunctions caused by 21 trisomy in neurons. Further research in this direction will likely yield additional insights, thereby improving our understanding of DS and potentially facilitating the development of new therapeutic approaches.
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Affiliation(s)
- Bruno H S Araujo
- Department of Neurosurgery and Neurology, Laboratory of Neuroscience, Universidade Federal de São Paulo (UNIFESP/EPM), São Paulo, São Paulo, Brazil. .,Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Rua Giuseppe Máximo Scolfaro, no. 10.000, Campinas, São Paulo, 13083-970, Brazil.
| | - Carolini Kaid
- Department of Genetics and Evolutionary Biology, Human Genome and Stem Cell Research Center, Institute of Biosciences, Universidade de São Paulo (USP), São Paulo, São Paulo, Brazil
| | - Janaina S De Souza
- Department of Medicine, Laboratory of Endocrinology and Translational Medicine, Universidade Federal de São Paulo (UNIFESP/EPM), São Paulo, São Paulo, Brazil
| | - Sérgio Gomes da Silva
- Hospital Israelita Albert Einstein (HIAE), São Paulo, São Paulo, Brazil.,Universidade de Mogi das Cruzes, Mogi das Cruzes, São Paulo, Brazil
| | - Ernesto Goulart
- Department of Genetics and Evolutionary Biology, Human Genome and Stem Cell Research Center, Institute of Biosciences, Universidade de São Paulo (USP), São Paulo, São Paulo, Brazil
| | - Luiz C J Caires
- Department of Genetics and Evolutionary Biology, Human Genome and Stem Cell Research Center, Institute of Biosciences, Universidade de São Paulo (USP), São Paulo, São Paulo, Brazil
| | - Camila M Musso
- Department of Genetics and Evolutionary Biology, Human Genome and Stem Cell Research Center, Institute of Biosciences, Universidade de São Paulo (USP), São Paulo, São Paulo, Brazil
| | - Laila B Torres
- São Leopoldo Mandic Institute and Research Center, Campinas, São Paulo, Brazil
| | - Adriano Ferrasa
- Experimental Multiuser Laboratory (LEM), Graduate Program in Health Sciences (PPGCS), School of Medicine, Pontifícia Universidade Católica do Paraná (PUCPR), Curitiba, Paraná, 80215-901, Brazil.,Department of Informatics (DEINFO), Universidade Estadual de Ponta Grossa (UEPG), Ponta Grossa, Paraná, 84030-900, Brazil
| | - Roberto Herai
- Department of Informatics (DEINFO), Universidade Estadual de Ponta Grossa (UEPG), Ponta Grossa, Paraná, 84030-900, Brazil
| | - Mayana Zatz
- Department of Genetics and Evolutionary Biology, Human Genome and Stem Cell Research Center, Institute of Biosciences, Universidade de São Paulo (USP), São Paulo, São Paulo, Brazil
| | - Oswaldo K Okamoto
- Department of Genetics and Evolutionary Biology, Human Genome and Stem Cell Research Center, Institute of Biosciences, Universidade de São Paulo (USP), São Paulo, São Paulo, Brazil
| | - Esper A Cavalheiro
- Department of Neurosurgery and Neurology, Laboratory of Neuroscience, Universidade Federal de São Paulo (UNIFESP/EPM), São Paulo, São Paulo, Brazil
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Araujo BHS, Torres LB, Guilhoto LMFF. Cerebal overinhibition could be the basis for the high prevalence of epilepsy in persons with Down syndrome. Epilepsy Behav 2015; 53:120-5. [PMID: 26558714 DOI: 10.1016/j.yebeh.2015.10.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Revised: 10/05/2015] [Accepted: 10/06/2015] [Indexed: 01/19/2023]
Abstract
Down syndrome (DS) is the most common cause of genetic intellectual disability, and the trisomy 21 is associated with more than 80 clinical traits, including higher risk for epilepsy. Several hypotheses have been put forward to explain the mechanisms underlying increased seizure susceptibility in DS: inherent structural brain abnormalities, abnormal cortical lamination, disruption of normal dendritic morphology, and underdeveloped synaptic profiles. A deficiency or loss of GABA inhibition is hypothesized to be one of the main alterations related to the epileptogenic process. Paradoxically, enhanced GABA inhibition has also been reported to promote seizures. One major functional abnormality observed in the brains of individuals and mouse models with DS appears to be an imbalance between excitatory and inhibitory neurotransmission, with excessive inhibitory brain function. This review discusses the GABAergic system in the human DS brain and the possible implication of the GABAergic network circuit in the epileptogenic process in individuals where the pathogenetic basis for epilepsy is unknown.
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Affiliation(s)
- Bruno Henrique Silva Araujo
- Universidade Federal de São Paulo - Unifesp/EPM, Department of Neurology and Neurosurgery - Laboratório de Neurociências, São Paulo, SP, Brazil.
| | - Laila Brito Torres
- Hospital Israelita Albert Einstein, São Paulo, SP, Brazil; Centro Sul Brasileiro de Pesquisa, Extensão e Pós-Graduação, CENSUPEG, Joinville, SC, Brazil
| | - Laura Maria F F Guilhoto
- Universidade Federal de São Paulo - Unifesp/EPM, Department of Neurology and Neurosurgery, São Paulo, SP, Brazil
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Haydar TF, Reeves RH. Trisomy 21 and early brain development. Trends Neurosci 2012; 35:81-91. [PMID: 22169531 PMCID: PMC3273608 DOI: 10.1016/j.tins.2011.11.001] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2011] [Revised: 09/17/2011] [Accepted: 11/01/2011] [Indexed: 12/13/2022]
Abstract
Trisomy for human chromosome 21 (Hsa21) results in Down syndrome (DS). The finished human genome sequence provides a thorough catalog of the genetic elements whose altered dosage perturbs development and function in DS. However, understanding how small alterations in the steady state transcript levels for <2% of human genes can disrupt development and function of essentially every cell presents a more complicated problem. Mouse models that recapitulate specific aspects of DS have been used to identify changes in brain morphogenesis and function. Here we provide a few examples of how trisomy for specific genes affects the development of the cortex and cerebellum to illustrate how gene dosage effects might contribute to divergence between the trisomic and euploid brains.
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Affiliation(s)
- Tarik F Haydar
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02118, USA.
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Glucocorticoids induce long-lasting effects in neural stem cells resulting in senescence-related alterations. Cell Death Dis 2010; 1:e92. [PMID: 21368868 PMCID: PMC3032322 DOI: 10.1038/cddis.2010.60] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Alterations in intrauterine programming occurring during critical periods of development have adverse consequences for whole-organ systems or individual tissue functions in later life. In this paper, we show that rat embryonic neural stem cells (NSCs) exposed to the synthetic glucocorticoid dexamethasone (Dex) undergo heritable alterations, possibly through epigenetic mechanisms. Exposure to Dex results in decreased NSC proliferation, with no effects on survival or differentiation, and changes in the expression of genes associated with cellular senescence and mitochondrial functions. Dex upregulates cell cycle-related genes p16 and p21 in a glucocorticoid receptor(GR)-dependent manner. The senescence-associated markers high mobility group (Hmg) A1 and heterochromatin protein 1 (HP1) are also upregulated in Dex-exposed NSCs, whereas Bmi1 (polycomb ring finger oncogene) and mitochondrial genes Nd3 (NADH dehydrogenase 3) and Cytb (cytochrome b) are downregulated. The concomitant decrease in global DNA methylation and DNA methyltransferases (Dnmts) suggests the occurrence of epigenetic changes. All these features are retained in daughter NSCs (never directly exposed to Dex) and are associated with a higher susceptibility to oxidative stress, as shown by the increased occurrence of apoptotic cell death on exposure to the redox-cycling reactive oxygen species (ROS) generator 2,3-dimethoxy-1-naphthoquinone (DMNQ). Our study provides novel evidence for programming effects induced by glucocorticoids (GCs) on NSCs and supports the idea that fetal exposure to endogenous or exogenous GCs is likely to result in long-term consequences that may predispose to neurodevelopmental and/or neurodegenerative disorders.
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Olig1 and Olig2 triplication causes developmental brain defects in Down syndrome. Nat Neurosci 2010; 13:927-34. [PMID: 20639873 PMCID: PMC3249618 DOI: 10.1038/nn.2600] [Citation(s) in RCA: 169] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Accepted: 06/21/2010] [Indexed: 11/08/2022]
Abstract
Over-inhibition is thought to be one of the underlying causes of the cognitive deficits in Ts65Dn mice, the most widely used model of Down syndrome. We found a direct link between gene triplication and defects in neuron production during embryonic development. These neurogenesis defects led to an imbalance between excitatory and inhibitory neurons and to increased inhibitory drive in the Ts65Dn forebrain. We discovered that Olig1 and Olig2, two genes that are triplicated in Down syndrome and in Ts65Dn mice, were overexpressed in the Ts65Dn forebrain. To test the hypothesis that Olig triplication causes the neurological phenotype, we used a genetic approach to normalize the dosage of these two genes and thereby rescued the inhibitory neuron phenotype in the Ts65Dn brain. These data identify seminal alterations during brain development and suggest a mechanistic relationship between triplicated genes and these brain abnormalities in the Ts65Dn mouse.
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Kim GJ, Lee ES. Prenatal diagnosis of transient abnormal myelopoiesis in a Down syndrome fetus. Korean J Radiol 2009; 10:190-3. [PMID: 19270866 PMCID: PMC2651437 DOI: 10.3348/kjr.2009.10.2.190] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Accepted: 07/22/2008] [Indexed: 11/21/2022] Open
Abstract
We report a case of transient abnormal myelopoiesis in a Down syndrome fetus diagnosed at 28+3 weeks of gestation that rapidly progressed to intrauterine death 10 days later. Fetal hepatosplenomegaly with cerebral ventriculomegaly, although not specific, may be a suggestive finding of Down syndrome with transient abnormal myelopoiesis. Prompt fetal blood sampling for liver function test and chromosomal analysis are mandatory for early detection and management.
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Affiliation(s)
- Gwang Jun Kim
- Department of Obstetric and Gynecology, Chung-Ang University School of Medicine, Seoul, Korea
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Exposure to brominated flame retardant PBDE-99 affects cytoskeletal protein expression in the neonatal mouse cerebral cortex. Neurotoxicology 2008; 29:628-37. [PMID: 18550172 DOI: 10.1016/j.neuro.2008.04.021] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Revised: 04/21/2008] [Accepted: 04/21/2008] [Indexed: 11/21/2022]
Abstract
Polybrominated diphenyl ethers (PBDEs) are environmental contaminants found in human and animal tissues worldwide. Neonatal exposure to the flame retardant 2,2', 4,4',5-pentabromodiphenyl ether (PBDE-99) disrupts normal brain development in mice, and results in disturbed spontaneous behavior in the adult. The mechanisms underlying the late effects of early exposure are not clear. To gain insight into the initial neurodevelopmental damage inflicted by PBDE-99, we investigated the short-term effects of PBDE-99 on protein expression in the developing cerebral cortex of neonatal mice, and the cytotoxic and apoptotic effects of PBDE-99 in primary cultures of fetal rat cortical cells. We used two-dimensional difference gel electrophoresis (2D-DIGE) to analyze protein samples isolated from the cortex of NMRI mice 24h after exposure to a single oral dose of 12 mg/kg PBDE-99 on post-natal day 10. Protein resolution was enhanced by sample pre-fractionation. In the cell model, we determined cell viability using the trypan blue exclusion assay, and apoptosis using immunocytochemical detection of cleaved caspase-3. We determined the identity of 111 differentially expressed proteins, 32 (29%) of which are known to be cytoskeleton-related. Similar to previous findings in the striatum, we found elevated levels of the neuron growth-associated protein Gap43 in the cortex. In cultured cortical cells, a high concentration of PBDE-99 (30 microM) induced cell death without any apparent increase in caspase-3 activity. These results indicate that the permanent neurological damage induced by PBDE-99 during the brain growth spurt involve detrimental effects on cytoskeletal regulation and neuronal maturation in the developing cerebral cortex.
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Chakrabarti L, Galdzicki Z, Haydar TF. Defects in embryonic neurogenesis and initial synapse formation in the forebrain of the Ts65Dn mouse model of Down syndrome. J Neurosci 2007; 27:11483-95. [PMID: 17959791 PMCID: PMC6673208 DOI: 10.1523/jneurosci.3406-07.2007] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2007] [Revised: 08/30/2007] [Accepted: 09/03/2007] [Indexed: 11/21/2022] Open
Abstract
Trisomy 21, one of the most prevalent congenital birth defects, results in a constellation of phenotypes collectively termed Down syndrome (DS). Mental retardation and motor and sensory deficits are among the many debilitating symptoms of DS. Alterations in brain growth and synaptic development are thought to underlie the cognitive impairments in DS, but the role of early brain development has not been studied because of the lack of embryonic human tissue and because of breeding difficulties in mouse models of DS. We generated a breeding colony of the Ts65Dn mouse model of DS to test the hypothesis that early defects in embryonic brain development are a component of brain dysfunction in DS. We found substantial delays in prenatal growth of the Ts65Dn cerebral cortex and hippocampus because of longer cell cycle duration and reduced neurogenesis from the ventricular zone neural precursor population. In addition, the Ts65Dn neocortex remains hypocellular after birth and there is a lasting decrease in synaptic development beginning in the first postnatal week. These results demonstrate that specific abnormalities in embryonic forebrain precursor cells precede early deficits in synaptogenesis and may underlie the postnatal disabilities in Ts65Dn and DS. The early prenatal period is therefore an important new window for possible therapeutic amelioration of the cognitive symptoms in DS.
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Affiliation(s)
- Lina Chakrabarti
- Center for Neuroscience Research, Children's National Medical Center, Washington, DC 20010, and
| | - Zygmunt Galdzicki
- Department of Anatomy, Physiology, and Genetics, Neuroscience Program, School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814
| | - Tarik F. Haydar
- Center for Neuroscience Research, Children's National Medical Center, Washington, DC 20010, and
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