Chromosome 21 Encoded RUNX1 and ETS-2 Overexpression in Regenerating Hematopoiesis in Children with Down Syndrome - Implications for Leukemiogenesis?.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4373-4373
Author(s):  
Dirk Reinhardt ◽  
Kristin Wortmann ◽  
Miriam Kolar ◽  
Jan H. Klusmann ◽  
Ulrike Puhlmann ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Down Syndrome ◽  
Trisomy 21 ◽  
Bone Marrow Cells ◽  
Gene Dosage ◽  
Gene Array ◽  
Chromosome 21 ◽  
Children With Down Syndrome ◽  
Increased Risk ◽  
Hematological Disorder

Abstract Children with Down Syndrome (DS) are at an 150 fold increased risk to develop acute megakaryoblastic leukemia (AMKL) within the first 4 years of life. About 10% of newborns with trisomy 21 showed transient myeloproliferative disorder (TMD). Although mutations of the transcriptional factor GATA1, resulting in the shortened GATA1s have been shown in almost all blasts in DS-AMKL and TMD the predisposition to leukemiogenesis related to trisomy 21 is not clear. TMD occurred during embryonic stress hematopoiesis leading to the hepatic proliferation of the GATA1s positive blasts. Typically blasts disappeared within the first 3 month of live, however after a median time of 1.3years (0.6 to 3.7 years) 20% of the children suffered AMKL and required intensive cytostatic treatment. The expression of chromosome 21 encoded hematological transcription factors (TFs) such RUNX1, ETS-2 and ERG were analysed in leukemic blasts from DS- TMD(n=7), DS-AMKL (n=25), DS without hematological disorder (n=10), AMKL (n=10) and healthy controls (n=7) by qRT-PCR. Results: No increase of RUNX1, ETS-2 and ERG expression could be shown. By contrast, ERG was decrease in all leukemias and in DS without hematological disorder (p Anova.<0.002). GATA1s was significantly overexpressed in TMD and DS-AMKL (pAnova <0.02), whereas GATA1 expression in AMKL and controls was not changed. GATA2 was elevated (pAnova <0.01) in all megakaryoblastic leukemias, with or without DS (pAnova <0.0001). PU.1, typically associated with early lymphatic differentiation and granulopoiesis was down regulated in all megakaryoblastic leukemias and, surprisingly, in DS without hematological disorder. This confirmed previously reported results by gene-array analysis1. To get further insight in the predisposition caused by trisomy 21 we analysed regenerating hematopoiesis in DS (n=14) partly resembling embryonic stress hematopoiesis. Correlated to the amount of bone marrow activation (CD38 positivity) a myeloid cell population (CD13/CD33 positive); with the co-expression of CD56 (NCAM) and CD36 (thrombospondin-receptor) could be detected by immunophenotyping (median percentage all nucleated bone marrow cells: 73±10%). In children without DS but regenerating hematopoiesis (n=41) a similar population of 4.6±1.8% (p<0.00001) could be detected. For further analysis the CD33/CD56 positive cells were sorted (FACSVantage). The cells showed normal myeloid morphology and differentiation, lack of GATA1s mutation, but an aberrant TF expression pattern. RUNX1 was 10-fold and ETS-2 5-fold higher expressed compared to controls (p<0.012). Summarized, (1) DS-AMKL and TMD leukemic blasts showed no general gene-dosage effect. However, (2) in stimulated bone marrow (stress hematopoiesis) trisomy 21 led to an overexpression of chromosome 21 encoded TFs, which might contribute to leukemiogenesis.

scholarly journals Investigating the Link Between Trisomy 21 and Acquired Mutations in the GATA1 Gene

The Physician ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. c9
Author(s):  
Triya Chakravorty ◽  
Irene Roberts
Keyword(s):  
Down Syndrome ◽  
Acute Myeloid Leukaemia ◽  
Myeloid Leukaemia ◽  
Trisomy 21 ◽  
Children With Down Syndrome ◽  
Transient Abnormal Myelopoiesis ◽  
Increased Risk ◽  
Leukaemic Cells ◽  
Acute Myeloid

Children with Down syndrome (DS) due to trisomy 21 (T21) are at an increased risk of developing the neonatal preleukaemic disorder transient abnormal myelopoiesis (TAM), which may transform into childhood acute myeloid leukaemia (ML-DS). Leukaemic cells in TAM and ML-DS have acquired mutations in the GATA1 gene. Although it is clear that acquired mutations in GATA1 are necessary for the development of TAM and ML-DS, questions remain concerning the mechanisms of disease.

Trisomy 21 Driven Pro-Inflammatory Signalling in Fetal Bone Marrow May Play a Role in Perturbed B-Lymphopoiesis and Acute Lymphoblastic Leukemia of Down Syndrome

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1206-1206 ◽  
Author(s):  
Sorcha Isabella O'Byrne ◽  
Natalina Elliott ◽  
Gemma Buck ◽  
Siobhan Rice ◽  
David O'Connor ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bone Marrow ◽  
Down Syndrome ◽  
Trisomy 21 ◽  
Lymphoblastic Leukemia ◽  
B Lymphopoiesis ◽  
Increased Risk ◽  
Cd34 Cells ◽  
Inflammatory Signalling

Introduction: Children with Down syndrome (DS) have a markedly increased risk of acute lymphoblastic leukemia (ALL), suggesting that trisomy 21 (T21) has specific effects on hematopoietic stem and progenitor cell (HSPC) biology in early life. Data from human fetal liver (FL) indicates that T21 alters fetal hematopoiesis, causing multiple defects in lympho-myelopoiesis. The impact of T21 on fetal B lymphopoiesis and how this may underpin the increase in ALL is not well known. We have recently found that fetal bone marrow (FBM) rather than FL is the main site of B lymphopoiesis; with a marked enrichment of fetal-specific progenitors (early lymphoid progenitors, ELP and PreProB progenitors) that lie upstream of adult type ProB progenitors (O'Byrne et al, Blood, in press). Previous preliminary data suggested that B progenitors were also reduced in T21 FBM (Roy et al, Blood. 124, 4331). Aim: To dissect putative molecular mechanisms responsible for the defects in T21 FBM B-lymphopoiesis and its association with childhood DS ALL. Methods: Second trimester human FBM and paediatric ALL samples were obtained from the Human Developmental Biology Resource and UK Childhood Leukaemia Cell Bank respectively. Multiparameter flow cytometry/sorting, transcriptome analysis by RNA-sequencing and microarray, and stromal co-culture assays were used to characterize HSPC and mesenchymal stromal cells (MSC) from normal (NM) disomic (n=21-35) and T21 (n=7-12) human FBM; RNASeq was performed on cytogenetically matched non-DS (n=13) and DS ALL (n=7). Results: In contrast to NM FBM, fetal specific progenitors were virtually absent (CD34+CD10-CD19-CD127+ ELP 2.8±0.4% vs. 0.8±0.4% of CD34+ cells) or very severely reduced (CD34+CD10-CD19+ PreProB 12.8±1 vs 2.6±0.7%) in T21 FBM. This was despite a >4-fold increase in the frequency of immunophenotypic HSC (4.2±1.2% vs 0.9±0.2% of CD34+ cells) and similar frequencies of MPP and LMPP in T21 FBM. As in adult BM, the vast majority of B progenitors in T21 FBM were CD34+CD10+CD19+ ProB progenitors with a frequency (28.8±8.3%) similar to NM FBM (30.3±2.3% of CD34+ cells). Thus, T21 causes a severe block in B-progenitor commitment at the LMPP stage, in tandem with a compensatory expansion of ProB progenitors. Consistent with this, T21 FBM HSC, MPP and LMPP had reduced B cell potential in vitro compared to NM FBM in MS5 co-cultures. RNAseq of NM (n=3) and T21 (n=3) FBM HSPC demonstrated global transcriptomic disruption by T21, with increased gene expression in HSC, MPP, LMPP and ProB progenitors. Cell cycle genes were enriched in T21 ProB progenitors. Despite these functional and global gene expression differences, expression of key B-lineage commitment genes was maintained suggesting the defect in B-lymphopoiesis may be secondary to lineage skewing of multipotent progenitors towards a non-B lymphoid fate and/or mediated by extrinsic factors. GSEA pointed to a role for multiple inflammatory pathways in T21 hematopoiesis with dysregulation of IFNα, IL6 and TGFβ signalling pathways in T21 HSC/LMPP. To investigate the role of the T21 microenvironment, we co-cultured NM HSC, MPP and LMPP with T21 or NM primary FBM MSC. T21 FBM MSC (n=3) had reduced capacity to support B cell differentiation in vitro consistent with perturbation of MSC function by T21. Similar to T21 FBM HSPC, transcriptomic analysis of T21 FBM MSC by microarray showed enrichment for IFNα signalling compared to NM; and T21 HSPC and MSC both showed increased gene expression for IFNα receptors IFNAR1 and IFNAR2, which are encoded on chromosome 21. Since IFNα was undetectable by ELISA of conditioned media from NM and T21 MSC, differences in secreted IFNα from MSC are unlikely to fully explain the increased IFN signalling in T21 HSPC and MSC. This suggests that T21 may drive autocrine rather than paracrine IFN signalling in FBM cells. Finally, RNASeq showed perturbed inflammatory signalling in DS ALL compared to non-DS ALL, suggesting a role for T21-driven inflammatory pathways in the biology of DS ALL. Conclusions: These data show that T21 severely impairs B lymphopoiesis in FBM and is associated with expression of proinflammatory gene expression programs in T21 FBM HSPC and MSC and DS ALL. The compensatory expansion of T21 FBM ProB progenitors, through self-renewal or via an alternative differentiation pathway; with concomitant T21-driven proinflammatory signalling may underpin the increased risk of B progenitor ALL in childhood. Disclosures No relevant conflicts of interest to declare.

scholarly journals Highly penetrant myeloproliferative disease in the Ts65Dn mouse model of Down syndrome

Blood ◽  
2008 ◽  
Vol 111 (2) ◽  
pp. 767-775 ◽  
Author(s):  
Gina Kirsammer ◽  
Sarah Jilani ◽  
Hui Liu ◽  
Elizabeth Davis ◽  
Sandeep Gurbuxani ◽  
...  
Keyword(s):  
Down Syndrome ◽  
Mouse Model ◽  
Gene Dosage ◽  
Hematologic Malignancies ◽  
Chromosome 21 ◽  
Myeloproliferative Disease ◽  
Ts65dn Mouse ◽  
Hematopoietic Stem ◽  
Megakaryoblastic Leukemia ◽  
Increased Risk

Children with Down syndrome (DS) display macrocytosis, thrombocytosis, and a 500-fold increased risk of developing megakaryocytic leukemia; however, the specific effects of trisomy 21 on hematopoiesis remain poorly defined. To study this question, we analyzed blood cell development in the Ts65Dn mouse model of DS. Ts65Dn mice are trisomic for 104 orthologs of Hsa21 genes and are the most widely used mouse model for DS. We discovered that Ts65Dn mice display persistent macrocytosis and develop a myeloproliferative disease (MPD) characterized by profound thrombocytosis, megakaryocyte hyperplasia, dysplastic megakaryocyte morphology, and myelofibrosis. In addition, these animals bear distorted hematopoietic stem and myeloid progenitor cell compartments compared with euploid control littermates. Of the 104 trisomic genes in Ts65Dn mice, Aml1/Runx1 attracts considerable attention as a candidate oncogene in DS–acute megakaryoblastic leukemia (DS-AMKL). To determine whether trisomy for Aml1/Runx1 is essential for MPD, we restored disomy at the Aml1/Runx1 locus in the Ts65Dn strain. Surprisingly, trisomy for Aml1/Runx1 is not required for megakaryocyte hyperplasia and myelofibrosis, suggesting that trisomy for one or more of the remaining genes can promote this disease. Our studies demonstrate the potential of DS mouse models to improve our understanding of chromosome 21 gene dosage effects in human hematologic malignancies.

scholarly journals Mapping the cellular origin and early evolution of leukemia in Down syndrome

Science ◽  
2021 ◽  
Vol 373 (6551) ◽  
pp. eabf6202 ◽  
Author(s):  
Elvin Wagenblast ◽  
Joana Araújo ◽  
Olga I. Gan ◽  
Sarah K. Cutting ◽  
Alex Murison ◽  
...  
Keyword(s):  
Stem Cells ◽  
Down Syndrome ◽  
Trisomy 21 ◽  
Chromosome 21 ◽  
Hematopoietic Stem ◽  
Developmental Context ◽  
Cellular Origin ◽  
Increased Risk ◽  
Stem And Progenitor Cells

Children with Down syndrome have a 150-fold increased risk of developing myeloid leukemia, but the mechanism of predisposition is unclear. Because Down syndrome leukemogenesis initiates during fetal development, we characterized the cellular and developmental context of preleukemic initiation and leukemic progression using gene editing in human disomic and trisomic fetal hematopoietic cells and xenotransplantation. GATA binding protein 1 (GATA1) mutations caused transient preleukemia when introduced into trisomy 21 long-term hematopoietic stem cells, where a subset of chromosome 21 microRNAs affected predisposition to preleukemia. By contrast, progression to leukemia was independent of trisomy 21 and originated in various stem and progenitor cells through additional mutations in cohesin genes. CD117+/KIT proto-oncogene (KIT) cells mediated the propagation of preleukemia and leukemia, and KIT inhibition targeted preleukemic stem cells.

scholarly journals Mapping the Cellular Origin and Early Evolution of Leukemia in Down Syndrome

2020 ◽  
Author(s):  
Elvin Wagenblast ◽  
Joana Araújo ◽  
Olga I. Gan ◽  
Sarah K. Cutting ◽  
Alex Murison ◽  
...  
Keyword(s):  
Stem Cells ◽  
Down Syndrome ◽  
Trisomy 21 ◽  
Fetal Liver ◽  
Chromosome 21 ◽  
Hematopoietic Stem ◽  
Cellular Origin ◽  
Increased Risk ◽  
Stem And Progenitor Cells ◽  
Cellular Context

AbstractChildren with Down syndrome have a 150-fold increased risk of developing myeloid leukemia, but the mechanism of predisposition is unclear. As Down syndrome leukemogenesis initiates during fetal development, we characterized the cellular context of preleukemic initiation and leukemic progression using gene editing in human disomic and trisomic fetal liver hematopoietic cells and xenotransplantation. GATA1 mutations caused transient preleukemia only when introduced into trisomy 21 long-term hematopoietic stem cells, where a subset of chromosome 21 miRNAs triggers predisposition to preleukemia. By contrast, progression to leukemia was independent of trisomy 21 and originated in various stem and progenitor cells through additional mutations in cohesin genes. CD117+/KIT cells mediated the propagation of preleukemia and leukemia, and functional KIT inhibition targeted preleukemic stem cells, blocking progression to leukemia.

scholarly journals Folate pathway metabolites are altered in the plasma of subjects with Down syndrome: relation to chromosomal dosage

2021 ◽  
Author(s):  
Beatrice Vione ◽  
Chiara Locatelli ◽  
Giacomo Zavaroni ◽  
Angela Piano ◽  
Giorgia La Rocca ◽  
...  
Keyword(s):  
Down Syndrome ◽  
Carbon Cycle ◽  
Trisomy 21 ◽  
Metabolic Diseases ◽  
Gene Dosage ◽  
Chromosome 21 ◽  
Congenital Defects ◽  
Control Subjects ◽  
Folate Pathway ◽  
The One

AbstractDown syndrome (DS) is the most common chromosomal disorder, and it is caused by trisomy of chromosome 21 (Hsa21). Subjects with DS can show a large heterogeneity of phenotypes and congenital defects and the most constant clinical features present are typical facies and intellectual disability (ID). Jérôme Lejeune was the first who hypothesized that DS could be a metabolic disease and he noted an alteration of the folate pathway (part of the one-carbon cycle) in trisomic cell lines and subjects with DS. Comparing DS with other metabolic diseases characterized by ID and altered folate pathway he hypothesized a possible correlation among them. Recently, a nuclear magnetic resonance (NMR) analysis of the detectable metabolic part in plasma and urine samples was performed, comparing a group of subjects with DS and a group of control subjects. The data showed a clear difference in the concentration of some metabolites (all involved in central metabolic processes) for the DS group, which was sometimes in agreement with gene dosage expected proportions (3:2). The aim of this work is to underline metabolic differences between subjects with DS and control subjects in order to better understand the dysregulation of the folate pathway in DS. For the first time, we performed enzyme-linked immunosorbent assays (ELISAs) to identify the concentration of 4 different intermediates of the one-carbon cycle, namely tetrahydrofolate (THF), 5-methyl-THF, 5-formyl-THF and S-adenosyl-homocysteine (SAH) in plasma samples obtained from 153 subjects with DS and 54 euploid subjects. Results highlight specific alterations of some folate pathway related metabolites. The relevance of these results for the biology of intelligence and its impairment in trisomy 21 is discussed leading to the proposal of 5-methyl-THF as the best candidate for a clinical trial aimed at restoring the dysregulation of folate pathway in trisomy 21 and improving cognitive skills of subjects with DS.

Down Syndrome

2017 ◽  
Author(s):  
George T Capone
Keyword(s):  
Down Syndrome ◽  
Trisomy 21 ◽  
Developmental Delays ◽  
Gene Dosage ◽  
Adult Life ◽  
Chromosome 21 ◽  
Extra Copy ◽  
Anatomical Features ◽  
Primary Mechanism ◽  
Dosage Imbalance

People with Down syndrome (trisomy 21) are distinguished by having an extra copy of chromosome 21. Chromosome 21 contains an estimated 562 genes, including 161 known to code for functional proteins, and at least 396 considered novel. Gene dosage imbalance is the primary mechanism, which results in the molecular, cellular, histological, and anatomical features characteristic of the condition. Throughout brain development, major neurobiological events go awry, resulting in a differently organized brain and characteristic developmental delays noted during infancy and the preschool years. The consequences of gene dosage imbalance continue to have repercussions on neurobiological function throughout childhood and adult life.

Modeling the Multi-Step Pathogenesis of Acute Myeloid Leukemia of Down Syndrome

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3579-3579
Author(s):  
Eric R. Lechman ◽  
Karin G. Hermans ◽  
Stephanie M. Dobson ◽  
Olga I. Gan ◽  
James A. Kennedy ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Down Syndrome ◽  
B Cell ◽  
Peripheral Blood ◽  
Trisomy 21 ◽  
Cell Development ◽  
B Cell Development ◽  
Bone Marrow Cellularity ◽  
Increased Risk ◽  
Marrow Cellularity

Abstract The multistep pathogenesis of Down Syndrome (DS)-associated pre-leukemia and subsequent progression to acute leukemia is one of the better characterized of all human blood malignancies. Children with DS have a 150 fold increased risk of developing acute megakaryoblastic leukemia (AMKL) and greater than 30 fold increased risk of developing B cell acute lymphoblastic leukemia (B-ALL). DS-AMKL is often preceded in late fetal development or soon after birth by a pre-leukemic syndrome termed transient myeloproliferative disorder (TMD), which is characterized by high numbers of abnormal megakaryocytes and megakaryoblasts in the circulation, spleen and liver. Previous work has demonstrated that constitutional trisomy 21 results in expansion of megakaryocyte-erythroid progenitors (MEP) in fetal liver (FL) with a concomitant reduction in fetal pre-pro-B cells. The expanded MEP population subsequently acquires an N-terminal truncating mutation in the transcription factor GATA1 (termed GATA1s), leading to selective expansion of a pre-leukemic erythromegakaryocytic blast population. While the majority of DS-TMD cases spontaneously resolve within 3 months, up to 15% of DS-TMD neonates can develop lethal progressive liver fibrosis. Progression to AMKL following spontaneous resolution of TMD is associated with acquisition of at least one additional germline mutation. While murine models implicate a role for trisomy 21 and GATA1s in the leukemogenic process, they do not faithfully recapitulate the pathology of the human disease. Previous attempts to model DS-associated TMD through xenotransplantation of DS-FL and DS-TMD cells have proven technically challenging. Therefore, there remains a need for a human model to investigate the genetic steps required for initiation of DS-TMD and progression to DS-AMKL. We previously identified a leukemia stem cell (LSC)-associated miRNA signature by sorting 13 adult AML patient samples into 4 sub-populations based on CD34/CD38 expression, followed by supervised analysis guided by the in vivo leukemia initiating capacity of each sub-population in an optimized xenotransplant model. Interestingly, the top three LSC-associated miRNA candidates are all located on chromosome 21. To determine the role of these miRNA in human leukemogenesis, we engineered a tri-cistronic lentivector for enforced expression. Compared to control vector-transduced cells, tri-cistronic vector-transduced Lin‒CD34+CD38‒ cord blood (CB) cells generated a myeloproliferative syndrome in xenotransplanted mice, with splenomegaly, enhanced CD45+ human bone marrow cellularity and blocked B cell development at the pro B cell stage. Human grafts were enriched for CD45+CD33+CD117+CD123+CD41lo/CD42lo cells in bone marrow, peripheral blood, spleen and liver. In the CD45‒ compartment, a distinct lineage switch was observed, with CD41+ megakaryocytic output supplanting normal CD235+ erythroid output. High numbers of CD41+CD42b+CD61+CD34lo human platelets were detected in peripheral blood and spleen. Blood films revealed large dysplastic platelets and megakaryoblast-like cells. Histology showed hCD45+ packed bone marrow cavities, with loss of normal architecture. Bone marrow, spleen and liver all showed extensive reticulin deposition. In the lineage negative (Lin-) fraction of BM, we observed an expansion in the proportion of human MEP and multi-lymphoid progenitors (MLP). To further model leukemic progression, we expressed GATA1s in combination with our tri-cistronic miRNA vector. Mice transplanted with double transduced cells showed intermediate levels of splenomegaly and bone marrow cellularity compared to mice transplanted with cells transduced with tri-cistronic vector alone. The addition of GATA1s induced a complete loss of B cell development while restoring erythroid development. In human Lin‒ cells isolated from the BM, addition of mutant GATA1s further augmented the proportion and total numbers of MEP while restoring the MLP compartment to normal levels. These data demonstrate that we have generated a human xenograft model of DS-TMD through enforced expression in normal CB cells of a tri-cistron comprising 3 LSC-associated miRNA in combination with mutant GATA1s. With this model in place, we plan to further interrogate the genetic lesions involved in progression from DS-TMD to DS-AMKL. Disclosures No relevant conflicts of interest to declare.

scholarly journals Dyslipidemia and Superoxide Dismutase Activity in Children with Down Syndrome

1970 ◽  
Vol 30 (3) ◽  
pp. 160-163
Author(s):  
P Goyal ◽  
R Singh ◽  
A Yadav ◽  
AK Dutta ◽  
J Bhattacharjee
Keyword(s):  
Superoxide Dismutase ◽  
Down Syndrome ◽  
Trisomy 21 ◽  
Serum Triglyceride ◽  
Chromosome 21 ◽  
Sod Activity ◽  
Over Expression ◽  
Children With Down Syndrome ◽  
Expression Of Genes ◽  
Significant Difference

Introduction: Down Syndrome (trisomy 21) provides an interesting natural model to study atherosclerosis, since these individuals appear to be protected from plaque formation. Methodology: We assessed the lipid levels, and superoxide dismutase (SOD) activity in 32 clinically diagnosed children of Down syndrome and 34 children matched for age and sex as controls. Results: SOD activity was found to be significantly higher (p=0.004) in children with Down Syndrome (mean=313.7 IU/ml) than in controls (mean140.2 IU/ ml). Significantly higher levels of serum triglyceride (154.7 mg/dl) and VLDL (33.9 mg/dl) were observed in Down Syndrome as compared to healthy controls (119.6 mg/dl and 23.9 mg/dl respectively; p<0.05 for each). However, the two groups did not show any significant difference in levels of serum HDL-C, LDL-C. Conclusion: The raised antioxidant activity of SOD, because of over expression of genes situated non chromosome 21, probably offers some protection against the development of atherosclerosis despite the occurrence of dyslipidemia. Key words: Chromosome 21; Down Syndrome; Trisomy 21; Superoxide dismutase.  DOI: 10.3126/jnps.v30i3.3919J Nep Paedtr Soc 2010;30(3):160-163

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