Project description:We generated human induced pluripotent stem cells (iPSCs) from trisomy 21 (T21) and euploid patient tissues with and without GATA1 mutations causing exclusive expression of truncated GATA1, termed GATA1short (GATA1s). Transcriptome analysis comparing expression levels of genes in GATA1s vs. wtGATA1-expressing progenitors demonstrated that GATA1s impairs erythropoiesis and enhances megakaryopoiesis and myelopoiesis in both T21 and euploid contexts in the iPSC-model system. We analyzed the transcriptome of (i) T21 iPSC-derived heamtopoietic progenitors expressing wtGATA1 (6 replicates) or GATA1s (3 replicates), as well as of (ii) euploid iPSC-derived progenitors expressing wtGATA1 (2 replicates) or GATA1s (2 replicates).
Project description:We modeled human Trisomy 21 primitive hematopoiesis using induced pluripotent stem cells (iPSCs). Primitive multipotent progenitor populations generated from Trisomy 21 iPSCs showed normal proliferative capacity and megakaryocyte production, enhanced erythropoiesis and reduced myeloid development compared to euploid iPSCs.
Project description:We generated human induced pluripotent stem cells (iPSCs) from trisomy 21 (T21) and euploid patient tissues with and without GATA1 mutations causing exclusive expression of truncated GATA1, termed GATA1short (GATA1s). Transcriptome analysis comparing expression levels of genes in GATA1s vs. wtGATA1-expressing progenitors demonstrated that GATA1s impairs erythropoiesis and enhances megakaryopoiesis and myelopoiesis in both T21 and euploid contexts in the iPSC-model system.
Project description:Children with trisomy 21 (T21) are highly predisposed to acute myeloid leukemia, which is preceded by a pre-leukemic transient abnormal myelopoiesis driven by truncating mutations in GATA1 (GATA1s). We investigated gene expression profiles in T21 and isogenic euploid hematopoietic progenitor cells (HPCs) derived from human induced pluripotent stem cells (iPSCs), in combination GATA1s and STAG2 mutations associated with T21 myeloid leukemia. We identified upregulation of interferon alpha/gamma responses and ribosome subunit pathways in gene set enrichment analysis in T21 versus euploid CD45+ hematopoietic cells, whereas pathways regulating genome integrity including mitotic spindle and G2/M checkpoint were downregulated. GATA1s in T21 cells led to downregulation of heme metabolism and apoptosis pathways as well as a further significant increase in the average expression of genes on chromosome 21. These results suggest that T21 and GATA1s mutations cooperate to disrupt normal HPC functions and cause myeloid lineage skewing.
Project description:Down syndrome, caused by trisomy 21, is a complex developmental disorder associated with intellectual disability and reduced growth of multiple organs. Structural pathologies are present at birth, reflecting embryonic origins. A fundamental unanswered question is how an extra copy of human chromosome 21 contributes to organ-specific pathologies that characterize individuals with Down syndrome. Relevant to the hallmark intellectual disability in Down syndrome, how does trisomy 21 affect neural development? We tested the hypothesis that trisomy 21 exerts effects on human neural development as early as neural induction. Bulk RNA sequencing was performed on isogenic trisomy 21 and euploid human induced pluripotent stem cells (iPSCs) at successive stages of neural induction: embryoid bodies at Day 6, early neuroectoderm at Day 10, and differentiated neuroectoderm at Day 17. Gene expression analysis revealed over 1,300 differentially expressed genes in trisomy 21 cells along the differentiation pathway compared to euploid controls. Less than 5% of the gene expression changes included upregulated chromosome 21 encoded genes at every timepoint. Genes involved in specific growth factor signaling pathways (Wnt and Notch), metabolism (including interferon response and oxidative stress), and extracellular matrix were altered in trisomy 21 cells. Further analysis revealed heterochronic expression of genes. This comprehensive analysis reveals that trisomy 21 impacts discrete developmental pathways at the earliest stages of neural development. Further, the results suggest that metabolic dysfunction arises early in embryogenesis in trisomy 21 and may thus affect development and function more broadly.
Project description: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 contribute to these defects. Importantly, we found that targeting DYRK1A pharmacologically or by shRNA results in a considerable correction of these defects. mRNA-seq profiling of iPS cells (4 euploid and 3 trisomy 21) derived from fibroblasts of monozygotic twins discordant for trisomy 21