Genomic and functional profiling of human Down syndrome neural progenitors implicates S100B and aquaporin 4 in cell injury.

Department of Human Physiology and Pharmacology, Vittorio Erspamer Faculty of Pharmacy, University of Rome La Sapienza, Rome, Italy.
Human Molecular Genetics (Impact Factor: 7.69). 03/2008; 17(3):440-57. DOI: 10.1093/hmg/ddm322
Source: PubMed

ABSTRACT Down syndrome (DS) is caused by trisomy of chromosome 21 and is characterized by mental retardation, seizures and premature Alzheimer's disease. To examine neuropathological mechanisms giving rise to this disorder, we generated multiple human DS neural progenitor cell (NPC) lines from the 19-21 week frontal cortex and characterized their genomic and functional properties. Microarray profiling of DS progenitors indicated that increased levels of gene expression were not limited to chromosome 21, suggesting that increased expression of genes on chromosome 21 altered transcriptional regulation of a subset of genes throughout the entire genome. Moreover, many transcriptionally dysregulated genes were involved in cell death and oxidative stress. Network analyses suggested that upregulated expression of chromosome 21 genes such as S100B and amyloid precursor protein activated the stress response kinase pathways, and furthermore, could be linked to upregulation of the water channel aquaporin 4 (AQP4). We further demonstrate in DS NPCs that S100B is constitutively overexpressed, that overexpression leads to increased reactive oxygen species (ROS) formation and activation of stress response kinases, and that activation of this pathway results in compensatory AQP4 expression. In addition, AQP4 expression could be induced by direct exposure to ROS, and siRNA inhibition of AQP4 resulted in elevated levels of ROS following S100B exposure. Finally, elevated levels of S100B-induced ROS and loss of AQP4 expression led to increased programmed cell death. These findings suggest that dysregulation of chromosome 21 genes in DS neural progenitors leads to increased ROS and thereby alters transcriptional regulation of cytoprotective, non-chromosome 21 genes in response to ongoing cellular insults.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Down syndrome (trisomy 21) is the most common viable chromosomal disorder with intellectual impairment and several other developmental abnormalities. Here, we report the generation and characterization of induced pluripotent stem cells (iPSCs) derived from monozygotic twins discordant for trisomy 21 in order to eliminate the effects of the variability of genomic background. The alterations observed by genetic analysis at the iPSC level and at first approximation in early development illustrate the developmental disease transcriptional signature of Down syndrome. Moreover, we observed an abnormal neural differentiation of Down syndrome iPSCs in vivo when formed teratoma in NOD-SCID mice, and in vitro when differentiated into neuroprogenitors and neurons. These defects were associated with changes in the architecture and density of neurons, astroglial and oligodendroglial cells together with misexpression of genes involved in neurogenesis, lineage specification and differentiation. Furthermore, we provide novel evidence that dual-specificity tyrosine-(Y)-phosphorylation regulated kinase 1A (DYRK1A) on chromosome 21 likely contributes to these defects. Importantly, we found that targeting DYRK1A pharmacologically or by shRNA results in a considerable correction of these defects.
    EMBO Molecular Medicine 12/2013; · 7.80 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Granulocyte-colony stimulating factor (G-CSF) has protective effects on many neurological diseases. Here, we aimed to test G-CSF's effects on perihematomal tissue injuries following intracerebral hemorrhage (ICH) and examine whether the effects were functionally dependent on vascular endothelial growth factor (VEGF) and aquaporin-4 (AQP4). We detected the expression of perihematomal VEGF, VEGF receptors (VEGFRs) and AQP4 at 1 d, 3 d and 7 d after ICH. Also, we examined the effects of G-CSF on tissue injuries by ICH in wild type mice, and tested whether such effects were VEGF and AQP4 dependent by using VEGFR inhibitor--SU5416 and AQP4 knock-out (AQP4(-/-)) mice. Furthermore, we assessed the related signal transduction pathways via astrocyte cultures. We found G-CSF highly increased perihematomal VEGF, VEGFR-2 and AQP4. Importantly, G-CSF led to neurological functional improvement in both types of mice by associating with reduction of brain edema, blood-brain barrier (BBB) permeability and neuronal death and apoptosis and statistical analysis suggested AQP4 was required for these effects. Besides, except BBB leakage alleviation, the above effects were attenuated but not counteracted by SU5416, suggesting involvement of VEGF. G-CSF up-regulated phosphorylation of extracellular signal-regulated kinase (ERK) and signal transducer and activator of transcription 3 (STAT3) as well as VEGF and AQP4 proteins in cultured astrocytes. The latter was inhibited by ERK and STAT3 inhibitors respectively. Our data suggest the protective effects of G-CSF on perihematomal tissue injuries after ICH are highly associated with the increased levels of VEGF and AQP4, possibly act through JNK and ERK pathways respectively.
    Neuroscience 12/2013; · 3.12 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Trisomy 21 is the most frequent genetic cause of cognitive impairment. To assess the perturbations of gene expression in trisomy 21, and to eliminate the noise of genomic variability, we studied the transcriptome of fetal fibroblasts from a pair of monozygotic twins discordant for trisomy 21. Here we show that the differential expression between the twins is organized in domains along all chromosomes that are either upregulated or downregulated. These gene expression dysregulation domains (GEDDs) can be defined by the expression level of their gene content, and are well conserved in induced pluripotent stem cells derived from the twins' fibroblasts. Comparison of the transcriptome of the Ts65Dn mouse model of Down's syndrome and normal littermate mouse fibroblasts also showed GEDDs along the mouse chromosomes that were syntenic in human. The GEDDs correlate with the lamina-associated (LADs) and replication domains of mammalian cells. The overall position of LADs was not altered in trisomic cells; however, the H3K4me3 profile of the trisomic fibroblasts was modified and accurately followed the GEDD pattern. These results indicate that the nuclear compartments of trisomic cells undergo modifications of the chromatin environment influencing the overall transcriptome, and that GEDDs may therefore contribute to some trisomy 21 phenotypes.
    Nature 04/2014; 508(7496):345-50. · 38.60 Impact Factor

Full-text (2 Sources)

Available from
May 31, 2014