ABSTRACT: Comprehensive gene expression assessment in prenatal DS lungs (n=19), and age-matched non-DS (n=19), was performed using high-throughput RNA sequencing (RNAseq)
Project description:We performed bulk RNAseq on whole hearts from foetuses with Down syndrome and age-matched, sex-matched euploid controls. Analysis showed the expected increased expression of the genes on Hsa21 that are present in 3 copies. Gene set enrichment analysis identified pathways that are altered in DS hearts.
Project description:Down syndrome (DS) results from trisomy of human chromosome 21 (HSA21), and DS research has been greatly advanced by the use of mouse models. We previously generated a humanized mouse model of DS, TcMAC21, which carries the long arm of HSA21. These mice exhibit learning and memory deficits, and may reproduce neurodevelopmental alterations observed in humans with DS. Here we performed histologic studies of the TcMAC21 forebrain from embryonic to adult stages. The TcMAC21 neocortex showed reduced proliferation of neural progenitors and delayed neurogenesis. These abnormalities were associated with a smaller number of projection neurons and interneurons. Further, (phospho-)proteomic analysis of adult TcMAC21 cortex revealed alterations in the phosphorylation levels of a series of synaptic proteins. The TcMAC21 mouse model shows similar brain development abnormalities as DS, and will be a valuable mode to investigate prenatal and postnatal causes of intellectual disability in humans with DS.
Project description:Trisomy 21 (Ts21) or Down syndrome (DS) is the most common genetic cause of intellectual disability. To investigate the consequences of Ts21 on human brain development, we have systematically analyzed the transcriptome of dorsolateral prefrontal cortex (DFC) and cerebellar cortex (CBC) using exon array mapping in DS and matched euploid control brains spanning from prenatal development to adulthood. We identify hundreds of differentially expressed (DEX) genes in the DS brains, many of which exhibit temporal changes in expression over the lifespan. To gain insight into how these DEX genes may cause specific DS phenotypes, we identified functional modules of co-expressed genes using several different bioinformatics approaches, including WGCNA and gene ontology analysis. A module comprised of genes associated with myelination, including those dynamically expressed over the course of oligodendrocyte development, was amongst those with the great levels of differential gene expression. Using Ts65Dn mouse line, the most common rodent model of DS, w e observed significant and novel defects in oligodendrocyte maturation and myelin ultrastructure; establishing a correlative proof-of-principle implicating myelin dysgenesis in DS. Thus, examination of the spatio-temporal transcriptome predicts specific cellular and functional events in the DS brain and is an outstanding resource for determining putative mechanisms involved in the neuropathology of DS.
Project description:Human Trisomy 21 (T21), which causes Down Syndrome (DS), is the most common known cause of intellectual disability. However, the molecular basis for DS phenotypic variability remains poorly understood. Here we used SWATH mass spectrometry (SWATH-MS) to quantify protein abundance and protein turnover in fibroblasts from a monozygotic twin pair discordant for T21, and to profile protein expression in 11 unrelated DS individuals and age-matched controls. The integration of the steady state and turnover proteomic data sets with transcript profiles indicated that protein-specific degradation of members of stoichiometric complexes presents a major determinant of T21 gene dosage outcome, a primary effect that was not apparent from genomic data. The data also reveal that T21 results in extensive proteome remodeling similarly affecting proteins encoded by all chromosomes. Finally, we found broad, organelle-specific posttranscriptional effects such as significant down-regulation of the mitochondrial proteome contributing DS hallmarks and variability.
Project description:Down syndrome (DS) is caused by triplication of Human chromosome 21 (Hsa21) and associated with an array of deleterious phenotypes, including mental retardation, heart defects and immunodeficiency. Genome-wide expression patterns of uncultured peripheral blood cells are useful to understanding of DS-associated immune dysfunction. We used a Human Exon microarray to characterize gene expression in uncultured peripheral blood cells derived from DS individuals and age-matched controls from two age groups: neonate (N) and child (C). A total of 174 transcript clusters (gene-level) with eight located on Hsa21 in N group and 383 transcript clusters including 56 on Hsa21 in C group were significantly dysregulated in DS individuals. Microarray data were validated by quantitative polymerase chain reaction. Functional analysis revealed that the dysregulated genes in DS were significantly enriched in two and six KEGG pathways in N and C group, respectively. These pathways included leukocyte trans-endothelial migration, B cell receptor signaling pathway and primary immunodeficiency, etc., which causally implicated dysfunctional immunity in DS. Our results provided a comprehensive picture of gene expression patterns in DS at the two developmental stages and pointed towards candidate genes and molecular pathways potentially associated with the immune dysfunction in DS.
Project description:The Ts1Cje mouse strain (Sago, 1998) contains a segmental trisomy of mouse chromosome 16 orthologous to the region of human chromosome 21 commonly associated with Down Syndrome. In this study, fetuses were obtained from wildtype mothers bred with either wildtype or Ts1Cje males. Gene expression profiles in fetal liver and placenta of wildtype and Ts1Cje fetuses were compared, to identify potential markers for application in human prenatal DS screening.
Project description:In order to characterize the differences between second trimester Down syndrome (DS) and euploid fetuses, we compared gene expression in uncultured amniotic fluid supernatant samples. We identified individually differentially expressed genes via paired t-tests in the matched samples, and a set of differentially expressed genes on chromosome 21 using Gene Set Enrichment Analysis. Functional pathway analysis of the resulting genes highlighted the importance of oxidative stress, ion transport, and G-protein signaling in the DS fetuses. We profiled seven DS expression samples and seven controls matched for gender and approximate gestational age..
Project description:Down syndrome (DS) patients frequently develop organ-specific autoimmune disorders, particularly endocrinopathies and coeliac disease, as well as an increased susceptibility to mucosal candidiasis. These clinical features resemble APECED (autoimmune-polyendocrinopathy-candidiasis-ectodermal-dystrophy), a monogenic condition due to mutations in the AIRE gene, located on 21q22.3 and already described as down-regulated in 21 trisomy. Here we investigated AIRE expression and global gene expression profiles in surgically removed thymuses from 14 DS infants and children with congenital heart defects and from 42 age-matched individuals with cardiac defect as an isolated malformation. Immunohistochemistry revealed significantly reduced AIRE expression in DS thymuses (70.48M-BM-149.59 positive cells/mm2 in DS X 154.70M-BM-161.16 in controls, p<0.0001). qPCR confirmed the lower expression of AIRE in DS thymuses. Global thymic RNA profiles from DS patients and controls revealed 407 genes significantly hypoexpressed in DS. Network transcriptional analysis showed that hypoexpressed genes are related to biological processes such as antigen processing and presentation of endogenous antigen (ERAP2, CD1D), negative (PRDX2) and positive (CD3D, CD74) thymic T-cell selection and homeostasis of number of cells (PRDX2). Altogether these findings may explain the high prevalence of autoimmune phenomena in DS patients. Moreover, our data are in accordance with previous findings of thymic abnormal development in DS patients, characterized by lymphocyte depletion, diminution of the cortex, and loss of corticomedullary demarcation. Global gene profiles indicate that in DS patients, the trisomic imbalance probably leads to thymic hypofunction. In conclusion, lower AIRE expression and the impairment of other crucial pathways for central tolerance could well explain the high prevalence of organ-specific autoimmune disorders in DS. Among the 14 DS infants and 42 age-matched individuals with cardiac defect, only 4 from each group provided enough biological material (thymus fragments) for isolation of high-quality RNA to perform array analysis. Eight thymic samples were analyzed: C1, C2, C3 and C4 are controls, and D1, D2, D3 and D4 are from patients with Down syndrome.
Project description:Down syndrome (DS) patients frequently develop organ-specific autoimmune disorders, particularly endocrinopathies and coeliac disease, as well as an increased susceptibility to mucosal candidiasis. These clinical features resemble APECED (autoimmune-polyendocrinopathy-candidiasis-ectodermal-dystrophy), a monogenic condition due to mutations in the AIRE gene, located on 21q22.3 and already described as down-regulated in 21 trisomy. Here we investigated AIRE expression and global gene expression profiles in surgically removed thymuses from 14 DS infants and children with congenital heart defects and from 42 age-matched individuals with cardiac defect as an isolated malformation. Immunohistochemistry revealed significantly reduced AIRE expression in DS thymuses (70.48±49.59 positive cells/mm2 in DS X 154.70±61.16 in controls, p<0.0001). qPCR confirmed the lower expression of AIRE in DS thymuses. Global thymic RNA profiles from DS patients and controls revealed 407 genes significantly hypoexpressed in DS. Network transcriptional analysis showed that hypoexpressed genes are related to biological processes such as antigen processing and presentation of endogenous antigen (ERAP2, CD1D), negative (PRDX2) and positive (CD3D, CD74) thymic T-cell selection and homeostasis of number of cells (PRDX2). Altogether these findings may explain the high prevalence of autoimmune phenomena in DS patients. Moreover, our data are in accordance with previous findings of thymic abnormal development in DS patients, characterized by lymphocyte depletion, diminution of the cortex, and loss of corticomedullary demarcation. Global gene profiles indicate that in DS patients, the trisomic imbalance probably leads to thymic hypofunction. In conclusion, lower AIRE expression and the impairment of other crucial pathways for central tolerance could well explain the high prevalence of organ-specific autoimmune disorders in DS.