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Embryonic Brain (embryonic + brain)
Selected AbstractsTransient expression of serotonin 5-HT4 receptors in the mouse developing thalamocortical projectionsDEVELOPMENTAL NEUROBIOLOGY, Issue 3 2010Erin R. Slaten Abstract The serotonin 5-HT4 receptor (5-HT4 -R) is an unusually complex G-protein coupled receptor that is likely to play important roles in brain development and that may underlie the comorbidity of central and peripheral abnormalities in some developmental disorders. We studied the expression of 5-HT4 -Rs in the developing mouse forebrain at embryonic days 13, 15, 17, and at postnatal days 3 and 14 by using immunohistochemistry, tract tracing, and quantitative RT-PCR. The developing thalamocortical projections transiently expressed 5-HT4 -Rs in the embryonic brain and the 5-HT4 -R expression in the forebrain changed from axonal to somatic around birth. From embryonic days 13,17, the forebrain mRNA levels of the 5-HT4(a) -R and 5-HT4(b) -R splice variants increased nine- and fivefold, respectively, whereas the levels of the 5-HT4(e) -R and 5-HT4(f) -R variants remained relatively low throughout the studied period of embryonic development. These results suggest that during development 5-HT4 -R expression undergoes a dynamic regulation and that this regulation may be important for the normal development of sensory and limbic processing. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2010. [source] Regulation of miRNA expression during neural cell specificationEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2005Lena Smirnova Abstract MicroRNA (miRNA) are a newly recognized class of small, noncoding RNA molecules that participate in the developmental control of gene expression. We have studied the regulation of a set of highly expressed neural miRNA during mouse brain development. Temporal control is a characteristic of miRNA regulation in C. elegans and Drosophila, and is also prominent in the embryonic brain. We observed significant differences in the onset and magnitude of induction for individual miRNAs. Comparing expression in cultures of embryonic neurons and astrocytes we found marked lineage specificity for each of the miRNA in our study. Two of the most highly expressed miRNA in adult brain were preferentially expressed in neurons (mir-124, mir-128). In contrast, mir-23, a miRNA previously implicated in neural specification, was restricted to astrocytes. mir-26 and mir-29 were more strongly expressed in astrocytes than neurons, others were more evenly distributed (mir-9, mir-125). Lineage specificity was further explored using reporter constructs for two miRNA of particular interest (mir-125 and mir-128). miRNA-mediated suppression of both reporters was observed after transfection of the reporters into neurons but not astrocytes. miRNA were strongly induced during neural differentiation of embryonic stem cells, suggesting the validity of the stem cell model for studying miRNA regulation in neural development. [source] The HUDSEN Atlas: a three-dimensional (3D) spatial framework for studying gene expression in the developing human brainJOURNAL OF ANATOMY, Issue 4 2010Janet Kerwin Abstract We are developing a three-dimensional (3D) atlas of the human embryonic brain using anatomical landmarks and gene expression data to define major subdivisions through 12 stages of development [Carnegie Stages (CS) 12,23; approximately 26,56 days post conception (dpc)]. Virtual 3D anatomical models are generated from intact specimens using optical projection tomography (OPT). Using mapaint software, selected gene expression data, gathered using standard methods of in situ hybridization and immunohistochemistry, are mapped to a representative 3D model for each chosen Carnegie stage. In these models, anatomical domains, defined on the basis of morphological landmarks and comparative knowledge of expression patterns in vertebrates, are linked to a developmental neuroanatomic ontology. Human gene expression patterns for genes with characteristic expression in different vertebrates (e.g. PAX6, GAD65 and OLIG2) are being used to confirm and/or refine the human anatomical domain boundaries. We have also developed interpolation software that digitally generates a full domain from partial data. Currently, the 3D models and a preliminary set of anatomical domains and ontology are available on the atlas pages along with gene expression data from approximately 100 genes in the HUDSEN Human Spatial Gene Expression Database (http://www.hudsen.org). The aim is that full 3D data will be generated from expression data used to define a more detailed set of anatomical domains linked to a more advanced anatomy ontology and all of these will be available online, contributing to the long-term goal of the atlas, which is to help maximize the effective use and dissemination of data wherever it is generated. [source] Regulation of glial development by cystatin CJOURNAL OF NEUROCHEMISTRY, Issue 1 2007Akiko Hasegawa Abstract Cystatin C (CysC) is an endogenous cysteine proteases inhibitor produced by mature astrocytes in the adult brain. Previously we isolated CysC as a factor activating the glial fibrillary acidic protein (GFAP) promoter, and showed that CysC is expressed in astrocyte progenitors during development. Here we show that protease inhibitor activity increased daily in conditioned medium, and that this activity was mainly a result of CysC released from primary cultured cells. Human CysC added to the culture medium of primary brain cells increased the number of GFAP-positive and nestin-positive cells. Human CysC also increased the number of neurospheres formed from embryonic brain, and thus it increases the number of neural stem/precursor cells in a manner similar to glycosylated rat CysC. The addition of a neutralizing antibody, on the other hand, greatly decreased the number of GFAP and glutamate aspartate transporter (GLAST)-positive astrocytes. This decrease was reversed by the addition of CysC but not by another cysteine protease inhibitor. Thus, the promotion of astrocyte development by CysC appears to be independent of its protease inhibitor activity. The antibody increased the number of oligodendrocytes and their precursors. Therefore, CysC modifies glial development in addition to its activity against neural stem/precursor cells. [source] MRG15, a component of HAT and HDAC complexes, is essential for proliferation and differentiation of neural precursor cellsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 7 2009Meizhen Chen Abstract Neurogenesis during development depends on the coordinated regulation of self-renewal and differentiation of neural precursor cells (NPCs). Chromatin regulation is a key step in self-renewal activity and fate decision of NPCs. However, the molecular mechanism or mechanisms of this regulation is not fully understood. Here, we demonstrate for the first time that MRG15, a chromatin regulator, is important for proliferation and neural fate decision of NPCs. Neuroepithelia from Mrg15 -deficient embryonic brain are much thinner than those from control, and apoptotic cells increase in this region. We isolated NPCs from Mrg15 -deficient and wild-type embryonic whole brains and produced neurospheres to measure the self-renewal and differentiation abilities of these cells in vitro. Neurospheres culture from Mrg15 -deficient embryo grew less efficiently than those from wild type. Measurement of proliferation by means of BrdU (bromodeoxyuridine) incorporation revealed that Mrg15 -deficient NPCs have reduced proliferation ability and apoptotic cells do not increase during in vitro culture. The reduced proliferation of Mrg15 -deficient NPCs most likely accounts for the thinner neuroepithelia in Mrg15 -deficient embryonic brain. Moreover, we also demonstrate Mrg15 -deficient NPCs are defective in differentiation into neurons in vitro. Our results demonstrate that MRG15 has more than one function in neurogenesis and defines a novel role for this chromatin regulator that integrates proliferation and cell-fate determination in neurogenesis during development. © 2008 Wiley-Liss, Inc. [source] The pars intercerebralis of the locust brain: A developmental and comparative studyMICROSCOPY RESEARCH AND TECHNIQUE, Issue 3 2002Peter Ludwig Abstract The anterior midline of the brain, also known as the pars intercerebralis, contains the largest collection of neurosecretory cells in the central nervous system of the grasshopper. In this study, we use immunocytochemical, intracellular staining, and histological methods to establish the ontogenies of the various cell types in the brain midline, and show how these cells contribute to the pars intercerebralis of the adult brain. We show that the adult pars intercerebralis develops from three distinct embryonic cell groups: (1) the median neurosecretory cells, which derive from a subset of neuroblasts in the protocerebral hemispheres, and which project axons to the corpora cardiaca; (2) the paired primary commissure pioneers, which derive directly from the mesectoderm of the dorsal median domain and whose axons project to the ventral nerve cord via the midline tract; and (3) the six progeny of the median precursor in the dorsal median domain, which share a common axonal projection with the primary commissure pioneers. Since the adult pars intercerebralis is a fusion product of these independent cellular components, it can only be understood in terms of its origins in the embryonic brain. When the expression pattern of the TERM-1 antigen is compared in subsets of median neurosecretory cells in a wide range of insect orders, the results suggests a common organizational Bauplan for the pars intercerebralis. This hypothesis is supported by the identification of putative homologs of the grasshopper primary commissure pioneers in all these insects. Microsc. Res. Tech. 56:174,188, 2002. © 2002 Wiley-Liss, Inc. [source] Expression of PTPRO in the interneurons of adult mouse olfactory bulbTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 2 2010Takenori Kotani PTPRO is a receptor-type protein tyrosine phosphatase (PTP) with a single catalytic domain in its cytoplasmic region and multiple fibronectin type III-like domains in its extracellular region. In the chick, PTPRO mRNA has been shown to be particularly abundant in embryonic brain, and PTPRO is implicated in axon growth and guidance during embryonic development. However, the temporal and spatial expression of PTPRO protein in the mammalian CNS, particularly in the juvenile and adult mammalian brain, has not been evaluated in any detail. By immunohistofluorescence analysis with a monoclonal antibody to PTPRO, we show that PTPRO is widely expressed throughout the mouse brain from embryonic day 16 to postnatal day 1, while expression is largely confined to the olfactory bulb (OB) and olfactory tubercle in the adult brain. In the OB, PTPRO protein is expressed predominantly in the external plexiform layer, the granule cell layer, and the glomerular layer (GL). In these regions, expression of PTPRO is predominant in interneurons such as ,-aminobutyric acid (GABA)-ergic or calretinin (CR)-positive granule cells. In addition, PTPRO is expressed in GABAergic, CR-positive, tyrosine hydroxylase-positive, or neurocalcin-positive periglomerular cells in the GL. Costaining of PTPRO with other neuronal markers suggests that PTPRO is likely to be localized to the dendrites or dendritic spines of these olfactory interneurons. Thus, PTPRO might participate in regulation of dendritic morphology or synapse formation of interneurons in the adult mouse OB. J. Comp. Neurol. 518:119,136, 2010. © 2009 Wiley-Liss, Inc. [source] Expression of PTPRO in the interneurons of adult mouse olfactory bulbTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 2 2010Takenori Kotani Abstract PTPRO is a receptor-type protein tyrosine phosphatase (PTP) with a single catalytic domain in its cytoplasmic region and multiple fibronectin type III-like domains in its extracellular region. In the chick, PTPRO mRNA has been shown to be particularly abundant in embryonic brain, and PTPRO is implicated in axon growth and guidance during embryonic development. However, the temporal and spatial expression of PTPRO protein in the mammalian CNS, particularly in the juvenile and adult mammalian brain, has not been evaluated in any detail. By immunohistofluorescence analysis with a monoclonal antibody to PTPRO, we show that PTPRO is widely expressed throughout the mouse brain from embryonic day 16 to postnatal day 1, while expression is largely confined to the olfactory bulb (OB) and olfactory tubercle in the adult brain. In the OB, PTPRO protein is expressed predominantly in the external plexiform layer, the granule cell layer, and the glomerular layer (GL). In these regions, expression of PTPRO is predominant in interneurons such as ,-aminobutyric acid (GABA)-ergic or calretinin (CR)-positive granule cells. In addition, PTPRO is expressed in GABAergic, CR-positive, tyrosine hydroxylase-positive, or neurocalcin-positive periglomerular cells in the GL. Costaining of PTPRO with other neuronal markers suggests that PTPRO is likely to be localized to the dendrites or dendritic spines of these olfactory interneurons. Thus, PTPRO might participate in regulation of dendritic morphology or synapse formation of interneurons in the adult mouse OB. J. Comp. Neurol. 518:119,136, 2010. © 2009 Wiley-Liss, Inc. [source] ORIGINAL ARTICLE: Tumor Necrosis Factor-,-Associated Mechanisms Affecting the Embryonic Response to CyclophosphamideAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 3 2009Keren Mammon Problem, We have previously shown that TNF-,,/, embryos are more sensitive to the exposure to cyclophosphamide (CP) compared with TNF-,+/+ embryos; however, the underlying mechanisms are not fully understood. Thus, in our present study, we tried to identify those molecules that might be responsible for the protective effect of the cytokine. Method of study, CP-treated TNF-,,/, and TNF-,+/+ embryos were analyzed for changes in apoptosis by TUNEL and flow cytometry, while cell proliferation was analyzed by BrdU incorporation. The expression of Bax, bcl-2, p53, the p65 subunit of NF-,B and I,B, was assessed by Western blotting and immunohistochemistry. Results, CP-treated TNF-,,/, embryos exhibited a more profound decrease in their weight, which was accompanied by an earlier appearance of cellular damage and apoptotic cells and an earlier decrease in cell proliferation in the embryonic brain compared with TNF-,+/+ embryos. Also, an increased percentage of Bax-positive cells and a decreased percentage of bcl-2-positive cells were detected in TNF-,,/, embryos 48 hr after exposure, which were accompanied by a decreased percentage of p53-positive cells. Conclusion, Our data implicate TNF-, to be involved in the protection of the embryo against CP teratogenicity, possibly via alteration in Bax, bcl-2 or p53 expression. [source] Association of MT-ND5 gene variation with mitochondrial respiratory control ratio and NADH dehydrogenase activity in Tibet chicken embryosANIMAL GENETICS, Issue 5 2007H. G. Bao Summary NADH dehydrogenase (complex I) couples the oxidation of NADH for the reduction of ubiquinone with the generation of a proton gradient that can be used for the synthesis of ATP. We have found a missense mutation in the MT-ND5 subunit of NADH dehydrogenase in the Tibet chicken breed. In the present study, the mitochondrial respiratory control ratio (RCR) and NADH dehydrogenase activity in Tibet chicken embryonic brain with different genotypes were measured. Significant differences between animals carrying mitochondria with the EF493865.1:m.1627A vs. EF493865.1:m.1627C alleles were observed for RCR and enzyme activity. [source] The type 1 cannabinoid receptor is highly expressed in embryonic cortical projection neurons and negatively regulates neurite growth in vitroEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2008Tania Vitalis Abstract In the rodent and human embryonic brains, the cerebral cortex and hippocampus transiently express high levels of type 1 cannabinoid receptors (CB1Rs), at a developmental stage when these areas are composed mainly of glutamatergic neurons. However, the precise cellular and subcellular localization of CB1R expression as well as effects of CB1R modulation in this cell population remain largely unknown. We report that, starting from embryonic day 12.5, CB1Rs are strongly expressed in both reelin-expressing Cajal-Retzius cells and newly differentiated postmitotic glutamatergic neurons of the mouse telencephalon. CB1R protein is localized first to somato-dendritic endosomes and at later developmental stages it localizes mostly to developing axons. In young axons, CB1Rs are localized both to the axolemma and to large, often multivesicular endosomes. Acute maternal injection of agonist CP-55940 results in the relocation of receptors from axons to somato-dendritic endosomes, indicating the functional competence of embryonic CB1Rs. The adult phenotype of CB1R expression is established around postnatal day 5. By using pharmacological and mutational modulation of CB1R activity in isolated cultured rat hippocampal neurons, we also show that basal activation of CB1R acts as a negative regulatory signal for dendritogenesis, dendritic and axonal outgrowth, and branching. Together, the overall negative regulatory role in neurite development suggests that embryonic CB1R signaling may participate in the correct establishment of neuronal connectivity and suggests a possible mechanism for the development of reported glutamatergic dysfunction in the offspring following maternal cannabis consumption. [source] Human neural stem cell transplantation attenuates apoptosis and improves neurological functions after cerebral ischemia in ratsACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2009P. ZHANG Background: Neuroprotection is a major therapeutic approach for ischemic brain injury. We investigated the neuroprotective effects induced by transplantation of human embryonic neural stem cells (NSCs) into the cortical penumbra 24 h after focal cerebral ischemia. Methods: NSCs were prepared from human embryonic brains obtained at 8 weeks of gestation. Focal cerebral ischemia was induced in adult rats by permanent occlusion of the middle cerebral artery. Animals were randomly divided into two groups: NSCs-grafted group and medium-grafted group (control). Infarct size was assessed 28 days after transplantation by hematoxylin and eosin staining. Neurological severity scores were evaluated before ischemia and at 1, 7, 14, and 28 days after transplantation. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay and immunohistochemical analysis of Bcl-2 and Bax were performed at 7, 14, and 28 days after transplantation. Results: Physiological parameters of the two groups were comparable, but not significantly different. NSC transplantation significantly improved neurological function (P<0.05) but did not reduce the infarct size significantly (P>0.05). Compared with the control, NSC transplantation significantly reduced the number of TUNEL- and Bax-positive cells in the penumbra at 7 days. Interestingly, the number of Bcl-2-positive cells in the penumbra after NSC transplantation was significantly higher than that after medium transplantation (P<0.05). Conclusions: The results indicate that NSC transplantation has anti-apoptotic activity and can improve the neurological function; these effects are mediated by the up-regulation of Bcl-2 expression in the penumbra. [source] Distinct spatio-temporal expression of ABCA and ABCG transporters in the developing and adult mouse brainJOURNAL OF NEUROCHEMISTRY, Issue 1 2005Masanori Tachikawa Abstract Using in situ hybridization for the mouse brain, we analyzed developmental changes in gene expression for the ATP-binding cassette (ABC) transporter subfamilies ABCA1,4 and 7, and ABCG1, 2, 4, 5 and 8. In the embryonic brains, ABCA1 and A7 were highly expressed in the ventricular (or germinal) zone, whereas ABCA2, A3 and G4 were enriched in the mantle (or differentiating) zone. At the postnatal stages, ABCA1 was detected in both the gray and white matter and in the choroid plexus. On the other hand, ABCA2, A3 and A7 were distributed in the gray matter. In addition, marked up-regulation of ABCA2 occurred in the white matter at 14 days-of-age when various myelin protein genes are known to be up-regulated. In marked contrast, ABCA4 was selective to the choroid plexus throughout development. ABCG1 was expressed in both the gray and white matters, whereas ABCG4 was confined to the gray matter. ABCG2 was diffusely and weakly detected throughout the brain at all stages examined. Immunohistochemistry of ABCG2 showed its preferential expression on the luminal membrane of brain capillaries. Expression signals for ABCG5 and G8 were barely detected at any stages. The distinct spatio-temporal expressions of individual ABCA and G transporters may reflect their distinct cellular expressions in the developing and adult brains, presumably, to regulate and maintain lipid homeostasis in the brain. [source] | |||||||||||||