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.

A Myeloproliferative Disorder in the Tc1 Mouse Model of Down Syndrome

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2790-2790
Author(s):  
Kate A. Alford ◽  
Lesley Vanes ◽  
Zhe Li ◽  
Stuart H. Orkin ◽  
Elizabeth M. C. Fisher ◽  
...  
Keyword(s):  
Down Syndrome ◽  
Mouse Model ◽  
Extramedullary Hematopoiesis ◽  
Myeloproliferative Disorder ◽  
Chromosome 21 ◽  
Gene Encoding ◽  
Megakaryoblastic Leukemia ◽  
Cell Counts ◽  
Hematopoietic Disorders

Abstract Down syndrome (DS) children have a one in ten chance of being diagnosed with leukemia within the first ten years of life. Acute megakaryoblastic leukemia (AMKL) is a subtype of acute myeloid leukemia (AML) that accounts for nearly 50% of these leukemias. AMKL is associated with a self-regressing neoplasia found almost exclusively in DS newborns called Transient Myeloproliferative Disorder (TMD). In all cases of TMD and DS-AMKL, leukemic blast cells show mutations in the gene encoding the hematopoietic transcription factor GATA1, resulting in production of a truncated form of the protein called GATA1s. Mutations in GATA1 are not seen in non-DS-AMKL or other DS leukemias and it is clear both trisomy of human chromosome 21 (HSA21) and a mutation in GATA1 are required for the development of both TMD and AMKL. However, it is unknown which genes on HSA21 need to be trisomic in order to predispose an individual with DS to AMKL. Our group has generated mice (termed the Tc1 mice) that contain an almost complete, freely segregating copy of HSA21. These mice display phenotypic features of DS. We have examined adult hematopoiesis in these mice. Blood samples taken from a cohort of Tc1 mice were examined from 4 weeks until 60 weeks of age. Complete blood cell counts show that whilst the mice do not develop leukemia they displayed persistent macrocytosis and had reduced erythrocyte numbers. Crossing the Tc1 mice with mice that express GATA1s protein did not perturb or exacerbate this phenotype. Over the age of 15 months more than 50% of Tc1 mice examined were found to have developed splenomegaly. These mice displayed megakaryocyte hyperplasia and had increased numbers of cells of the erythroid lineage. In vitro colony forming assays demonstrated an increase in the frequency of megakaryocytic and granulocyte-macrophage progenitors in the spleen, consistent with extramedullary hematopoiesis. In the bone marrow, no abnormalities were seen in the lineage-, c-Kit+, Sca1+ (LSK) compartment, however there was a significant increase in the percentage of common myeloid progenitors (CMP) and a corresponding decrease in megakaryocyte-erythrocyte progenitors (MEP). This suggests a possible block in development from CMP to MEP. These data demonstrate defects in hematopoietic development in a proportion of adult Tc1 mice. However, preliminary data suggest that these mice do not develop a neonatal myeloproliferative disorder that is comparable with human TMD. It may be that the phenotype seen in the adult Tc1 mice is due to defects in hematopoietic progenitors that are different to those responsible for development of TMD and DS-AMKL. This mouse model may therefore provide a useful tool to examine the role of HSA21 genes in adult hematopoietic disorders.

scholarly journals Neurodevelopmental wiring deficits in the Ts65Dn mouse model of Down syndrome

2019 ◽  
Author(s):  
Shruti Jain ◽  
Christina A. Watts ◽  
Wilson C.J. Chung ◽  
Kristy Welshhans
Keyword(s):  
Down Syndrome ◽  
Corpus Callosum ◽  
Mouse Model ◽  
Hippocampal Neurons ◽  
Anterior Commissure ◽  
Axon Growth ◽  
Chromosome 21 ◽  
Ts65dn Mouse ◽  
Hippocampal Commissure ◽  
Interhemispheric Connectivity

AbstractDown syndrome is the most common genetic cause of intellectual disability and occurs due to the trisomy of human chromosome 21. Adolescent and adult brains from humans with Down syndrome exhibit various neurological phenotypes including a reduction in the size of the corpus callosum, hippocampal commissure and anterior commissure. However, it is unclear when and how these interhemispheric connectivity defects arise. Using the Ts65Dn mouse model of Down syndrome, we examined interhemispheric connectivity in postnatal day 0 (P0) Ts65Dn mouse brains. We find that there is no change in the volume of the corpus callosum or anterior commissure in P0 Ts65Dn mice. However, the volume of the hippocampal commissure is significantly reduced in P0 Ts65Dn mice, and this may contribute to the impaired learning and memory phenotype of this disorder. Interhemispheric connectivity defects that arise during development may be due to disrupted axon growth. In line with this, we find that developing hippocampal neurons display reduced axon length in vitro, as compared to neurons from their euploid littermates. This study is the first to report the presence of defective interhemispheric connectivity at the time of birth in Ts65Dn mice, providing evidence that early therapeutic intervention may be an effective time window for the treatment of Down syndrome.

scholarly journals Adult-Onset Fluoxetine Treatment Does Not Improve Behavioral Impairments and May Have Adverse Effects on the Ts65Dn Mouse Model of Down Syndrome

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Markus Heinen ◽  
Moritz M. Hettich ◽  
Devon P. Ryan ◽  
Susanne Schnell ◽  
Katharina Paesler ◽  
...  
Keyword(s):  
Down Syndrome ◽  
Mouse Model ◽  
Chromosome 21 ◽  
Adult Onset ◽  
Ts65dn Mouse ◽  
Receptor Antagonists ◽  
Memory Impairments ◽  
Severe Intellectual Disability ◽  
Fluoxetine Treatment ◽  
Behavioral Impairments

Down syndrome is caused by triplication of chromosome 21 and is associated with neurocognitive phenotypes ranging from severe intellectual disability to various patterns of more selective neuropsychological deficits, including memory impairments. In the Ts65Dn mouse model of Down syndrome, excessive GABAergic neurotransmission results in local over-inhibition of hippocampal circuits, which dampens hippocampal synaptic plasticity and contributes to cognitive impairments. Treatments with several GABAAreceptor antagonists result in increased plasticity and improved memory deficits in Ts65Dn mice. These GABAAreceptor antagonists are, however, not suitable for clinical applications. The selective serotonin reuptake inhibitor fluoxetine, in contrast, is a widely prescribed antidepressant that can also enhance plasticity in the adult rodent brain by lowering GABAergic inhibition. For these reasons, we wondered if an adult-onset 4-week oral fluoxetine treatment restores spatial learning and memory impairments in Ts65Dn mice. Fluoxetine did not measurably improve behavioral impairments of Ts65Dn mice. On the contrary, we observed seizures and mortality in fluoxetine-treated Ts65Dn mice, raising the possibility of a drug × genotype interaction with respect to these adverse treatment outcomes. Future studies should re-address this in larger animal cohorts and determine if fluoxetine treatment is associated with adverse treatment effects in individuals with Down syndrome.

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.

Trisomy of Erg is required for myeloproliferation in a mouse model of Down syndrome

Blood ◽  
2010 ◽  
Vol 115 (19) ◽  
pp. 3966-3969 ◽  
Author(s):  
Ashley P. Ng ◽  
Craig D. Hyland ◽  
Donald Metcalf ◽  
Catherine L. Carmichael ◽  
Stephen J. Loughran ◽  
...  
Keyword(s):  
Down Syndrome ◽  
Mouse Model ◽  
Trisomy 21 ◽  
Progenitor Cell ◽  
Gene Dosage ◽  
Myeloproliferative Disorder ◽  
Chromosome 21 ◽  
Loss Of Function ◽  
Hematologic Disorders ◽  
Acute Megakaryocytic Leukemia

Abstract Down syndrome is characterized by multiple phenotypic manifestations associated with trisomy of chromosome 21. The transient myeloproliferative disorder and acute megakaryocytic leukemia associated with Down syndrome are uniquely associated with mutations in the transcription factor GATA1; however, the identity of trisomic genes on chromosome 21 that predispose to these hematologic disorders remains unknown. Using a loss-of-function allele, we show that specific reduction to functional disomy of the Erg gene corrects the pathologic and hematologic features of myeloproliferation in the Ts(1716)65Dn mouse model of Down syndrome, including megakaryocytosis and progenitor cell expansion. Our data provide genetic evidence establishing the need for Erg trisomy for myeloproliferation in Ts(1716)65Dn mice and imply that increased ERG gene dosage may be a key consequence of trisomy 21 that can predispose to malignant hematologic disorders in Down syndrome.

scholarly journals Perturbed hematopoiesis in the Tc1 mouse model of Down syndrome

Blood ◽  
2010 ◽  
Vol 115 (14) ◽  
pp. 2928-2937 ◽  
Author(s):  
Kate A. Alford ◽  
Amy Slender ◽  
Lesley Vanes ◽  
Zhe Li ◽  
Elizabeth M. C. Fisher ◽  
...  
Keyword(s):  
Down Syndrome ◽  
Mouse Model ◽  
Lymphoblastic Leukemia ◽  
Macrocytic Anemia ◽  
Extramedullary Hematopoiesis ◽  
Chromosome 21 ◽  
Acute Megakaryoblastic Leukemia ◽  
Megakaryoblastic Leukemia ◽  
Human Chromosome 21 ◽  
Synergistic Increase

Abstract Trisomy of human chromosome 21 (Hsa21) results in Down syndrome (DS), a disorder that affects many aspects of physiology, including hematopoiesis. DS children have greatly increased rates of acute lymphoblastic leukemia and acute megakaryoblastic leukemia (AMKL); DS newborns present with transient myeloproliferative disorder (TMD), a preleukemic form of AMKL. TMD and DS-AMKL almost always carry an acquired mutation in GATA1 resulting in exclusive synthesis of a truncated protein (GATA1s), suggesting that both trisomy 21 and GATA1 mutations are required for leukemogenesis. To gain further understanding of how Hsa21 contributes to hematopoietic abnormalities, we examined the Tc1 mouse model of DS, which carries an almost complete freely segregating copy of Hsa21, and is the most complete model of DS available. We show that although Tc1 mice do not develop leukemia, they have macrocytic anemia and increased extramedullary hematopoiesis. Introduction of GATA1s into Tc1 mice resulted in a synergistic increase in megakaryopoiesis, but did not result in leukemia or a TMD-like phenotype, demonstrating that GATA1s and trisomy of approximately 80% of Hsa21 perturb megakaryopoiesis but are insufficient to induce leukemia.

scholarly journals Defective Hematopoietic Stem Cell and Lymphoid Progenitor Development in the Ts65Dn Mouse Model of Down Syndrome: Potential Role of Oxidative Stress

2011 ◽  
Vol 15 (8) ◽  
pp. 2083-2094 ◽  
Author(s):  
Laureanne Pilar E. Lorenzo ◽  
Haiyan Chen ◽  
Kristen E. Shatynski ◽  
Sarah Clark ◽  
Rong Yuan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Down Syndrome ◽  
Stem Cell ◽  
Mouse Model ◽  
Hematopoietic Stem Cell ◽  
Potential Role ◽  
Ts65dn Mouse ◽  
Hematopoietic Stem
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