Project description:RPS19 mutations are the most common cause of the human disorder Diamond Blackfan Anemia. The R62W mutation was hypothesized to act in a dominant negative fashion and mice expressing RPS19R62W have many of the characteristics of Diamond Blackfan Anemia. Diamond-Blackfan Anemia (DBA), is an inherited erythroblastopenia associated with mutations in at least 8 different ribosomal protein genes. Mutations in the gene encoding Ribosomal Protein S19 (RPS19) have been identified in ~25% of DBA families. Most of these mutations disrupt either the translation or stability of the RPS19 protein and are predicted to cause DBA by haploinsufficiency. However, approximately ~30% of RPS19 mutations are missense mutations that do not alter the stability of the RPS19 protein and are hypothesized to act by a dominant negative mechanism. To formally test this hypothesis, we generated a transgenic mouse model expressing an RPS19 mutation in which an Arginine residue is replaced with a Tryptophan residue at codon 62 (RPS19R62W). Constitutive expression of RPS19R62W in developing mice was lethal. Conditional expression of RPS19R62W resulted in growth retardation, a mild anemia with reduced numbers of erythroid progenitors and significant inhibition of terminal erythroid maturation, similar to DBA. RNA profiling demonstrated over 700 dysregulated genes belonging to the same pathways that are disrupted in RNA profiles of DBA patient cells.
Project description:Diamond-Blackfan anemia (DBA) is characterized by anemia and cancer susceptibility, and is caused by mutations in ribosomal genes, including Rpl11. Here, we report that Rpl11-heterozygous embryos are not viable, and homozygous deletion of Rpl11 in adult mice results in death within a few weeks, accompanied by bone marrow aplasia and intestinal atrophy. Importantly, deletion of a single Rpl11 allele in adult mice results in anemia associated to decreased erythroid progenitors and defective erythroid maturation. These phenotypes are also present in mice transplanted with inducible heterozygous Rpl11 bone marrow, indicating a cell-autonomous role of RPL11 in erythropoiesis. Additionally, fibroblasts lacking one or both Rpl11 alleles show defective p53 activation upon ribosomal stress or DNA damage. Furthermore, fibroblasts and hematopoietic tissues from heterozygous Rpl11 mice present higher basal cMYC levels. Accordingly, heterozygous Rpl11 mice are highly susceptible to radiation-induced lymphomagenesis. We conclude that Rpl11-deficient mice recapitulate DBA disorder, including cancer predisposition. RNAseq profiles of bone marrow hematopoietic progenitors cells from WT (Rpl11+/+:: Tg.UbC-CreERT2) and LOX (Rpl11+/lox::Tb.Ub-CreERT2) mice, n=4 independent animals per genotype
Project description:This RNA sequencing experiment is part of the study \\"Preclinical animal model of Diamond-Blackfan anemia with single amino acid mutation of ribosomal protein Rps19\\". A mouse model with conserved arginine 67 deletion of ribosomal protein Rps19 mutation develops features characteristic of human Diamond-Blackfan anemia, a rare bone marrow failure syndrome, including hematologic dysfunctions, early onset growth delay, intrinsic anemia, severe craniofacial, skeletal, urogenital, cardiovascular, and cerebral abnormalities leading to premature lethality during the adolescence of the mouse. This DBA mouse model exhibits cell intrinsic activation of the Trp53 signaling pathway in hematopoietic stem cells (HSCs) leading to reduced erythroid lineage development that may be rescued after inactivation of the tumor suppressor Trp53. The E14.5 fetal liver transcriptome analysis study confirms the involvement of non-canonical components of the p53 signaling pathway in the etiopathogenesis of DBA, manifested already during fetal development, consistent with the early onset of DBA-like phenotypes in mouse embryos as well as development of the disease in neonatal human patients. These results confirm our previous findings in adult hematopoietic progenitors as well as indicate that the development of DBA occurs well into the fetal development in both humans and our mouse model.
Project description:Diamond-Blackfan anemia (DBA) is characterized by anemia and cancer susceptibility, and is caused by mutations in ribosomal genes, including Rpl11. Here, we report that Rpl11-heterozygous embryos are not viable, and homozygous deletion of Rpl11 in adult mice results in death within a few weeks, accompanied by bone marrow aplasia and intestinal atrophy. Importantly, deletion of a single Rpl11 allele in adult mice results in anemia associated to decreased erythroid progenitors and defective erythroid maturation. These phenotypes are also present in mice transplanted with inducible heterozygous Rpl11 bone marrow, indicating a cell-autonomous role of RPL11 in erythropoiesis. Additionally, fibroblasts lacking one or both Rpl11 alleles show defective p53 activation upon ribosomal stress or DNA damage. Furthermore, fibroblasts and hematopoietic tissues from heterozygous Rpl11 mice present higher basal cMYC levels. Accordingly, heterozygous Rpl11 mice are highly susceptible to radiation-induced lymphomagenesis. We conclude that Rpl11-deficient mice recapitulate DBA disorder, including cancer predisposition.
Project description:RPS19 mutations are the most common cause of the human disorder Diamond Blackfan Anemia. The R62W mutation was hypothesized to act in a dominant negative fashion and mice expressing RPS19R62W have many of the characteristics of Diamond Blackfan Anemia. Diamond-Blackfan Anemia (DBA), is an inherited erythroblastopenia associated with mutations in at least 8 different ribosomal protein genes. Mutations in the gene encoding Ribosomal Protein S19 (RPS19) have been identified in ~25% of DBA families. Most of these mutations disrupt either the translation or stability of the RPS19 protein and are predicted to cause DBA by haploinsufficiency. However, approximately ~30% of RPS19 mutations are missense mutations that do not alter the stability of the RPS19 protein and are hypothesized to act by a dominant negative mechanism. To formally test this hypothesis, we generated a transgenic mouse model expressing an RPS19 mutation in which an Arginine residue is replaced with a Tryptophan residue at codon 62 (RPS19R62W). Constitutive expression of RPS19R62W in developing mice was lethal. Conditional expression of RPS19R62W resulted in growth retardation, a mild anemia with reduced numbers of erythroid progenitors and significant inhibition of terminal erythroid maturation, similar to DBA. RNA profiling demonstrated over 700 dysregulated genes belonging to the same pathways that are disrupted in RNA profiles of DBA patient cells. The samples compared are RNA extracted from CD71 positive erythroblasts sorted from the bone marrow of wild type mice and mice expressing a mutant RPS19 (RPS19R62W) transgene
Project description:This single cell transcriptome sequencing experiment is part of the study \\"Preclinical animal model of Diamond-Blackfan anemia with single amino acid mutation of ribosomal protein Rps19\\". A mouse model with this mutation develops features characteristic of human Diamond-Blackfan anemia, a rare bone marrow failure syndrome, including hematologic dysfunctions, early onset growth delay, intrinsic anemia, severe craniofacial, skeletal, urogenital, cardiovascular, and cerebral abnormalities leading to premature lethality during the adolescence of the mouse. This DBA mouse model exhibits cell intrinsic activation of the Trp53 signaling pathway in hematopoietic stem cells (HSCs) leading to reduced erythroid lineage development that may be rescued after inactivation of the tumor suppressor Trp53. The study uncovers that the development of the DBA phenotype significantly involves non-canonical components of the p53 signaling pathway in the etiopathogenesis of DBA with the Rps19R67∆ mutation leading to the disrupted hematopoietic hierarchy starting at the stage of short-term repopulating stem cells and the central role of induced Trp53 expression and upregulation of its non-canonical targets in the mediation of neural crest lineage deficiency-mediated development of craniofacial malformations in this model.
Project description:Transcriptome profile of highly purified multipotential (P), erythroid (E), and myeloid (M) bone marrow progenitors from three RPS19 mutated Diamond-Blackfan anemia and six control human subjects. Two group comparison of sex and age matched subjects. Bone marrow progenitors, gene expression profiling, Diamond-Blackfan anemia, RPS19
Project description:This RNA sequencing experiment is part of the study "Preclinical animal model of Diamond-Blackfan anemia with single amino acid mutation of ribosomal protein Rps19". A mouse model with arginine 67 mutation of ribosomal protein Rps19 develops features characteristic of human Diamond-Blackfan anemia, a rare bone marrow failure syndrome. These include hematologic dysfunctions, early onset growth delay, intrinsic anemia, severe craniofacial, skeletal, urogenital, cardiovascular, and cerebral abnormalities leading to premature lethality during the adolescence of the mouse. This model exhibits cell intrinsic activation of the Trp53 signaling pathway in hematopoietic stem cells (HSCs) leading to reduced erythroid lineage development that may be rescued after inactivation of the tumor suppressor Trp53. Using preliminary RNA sequencing study we identify a set of non-canonical components of the p53 signaling pathway which with high likelihood mediate the wide range of pathologies associated with DBA, the experiment if followed up by single cell transcriptome analysis of bone marrow hematopoietic progenitors and RNA sequencing of E14.5 fetal liver from wild-type control and Rps19R67∆/R67∆, Rps19R67∆/R67∆ Trp53−/− and Trp53−/− mutant embryos.
Project description:Ribosome dysfunction underlies the pathogenesis of many cancers and heritable ribosomopathies. Here we investigate how mutations in either ribosomal protein large (RPL) or ribosomal protein small (RPS) subunit genes selectively affect erythroid progenitor development and clinical phenotypes in Diamond-Blackfan anemia (DBA), a rare ribosomopathy with limited therapeutic options. Using single-cell assays of patient-derived bone marrow, we delineated two distinct cellular trajectories segregating with ribosomal protein genotypes: almost complete loss of erythroid specification were observed in RPS-DBA. In contrast, we observed relative preservation of qualitatively abnormal erythroid progenitors and precursors in RPL-DBA. Although both DBA genotypes exhibited a pro-inflammatory bone marrow milieu, RPS-DBA was characterized by erythroid differentiation arrest, whereas RPL-DBA was characterized by preserved GATA1 expression and activity. Compensatory stress erythropoiesis in RPL-DBA exhibited disordered differentiation underpinned by an altered glucocorticoid molecular signature, including reduced ZFP36L2 expression, leading to milder anemia and improved corticosteroid response. This integrative analysis approach identified distinct pathways of erythroid failure and defined genotype-phenotype correlations in DBA. These findings may help facilitate therapeutic target discovery.
Project description:Diamond Blackfan anemia is a congenital bone marrow failure syndrome characterized by hypoproliferative anemia, often with associated physical abnormalities. Perturbations of the ribosome appear critically important to the development of DBA, as alterations in 9 different ribosomal protein genes have been identified in multiple unrelated families, along with rarer abnormalities of additional ribosomal proteins. However, presently only 50-60% of patients have an identifiable genetic lesion by ribosomal protein gene sequencing. Using genome-wide SNP array to evaluate for regions of recurrent copy variation, we identified 2 patients with mosaic loss in the region of the the chromosome 5-deleted region involved in somatically-acquired 5q- myelodysplastic syndrome.