| 1. |
- Schneppenheim, Reinhard, et al.
(författare)
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A common origin of the 4143insA ADAMTS13 mutation
- 2006
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Ingår i: Thrombosis and Haemostasis. - 0340-6245. ; 96:1, s. 3-6
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Tidskriftsartikel (refereegranskat)abstract
- Severely deficient activity of the von Willebrand Factor (VWF) cleaving metalloprotease,ADAMTS 13, is associated with thrombotic thrombocytopenic purpura (TTP). The mutation spectrum ofADAMTS 13 is rather heterogeneous, and numerous mutations spread across the gene have been described in association with congenital TTP. The 4143insA mutation is unusual with respect to its geographic concentration. Following the initial report from Germany in which the 4143insA mutation was detected in four apparently unrelated families, we have now identified this mutation in a further eleven patients from Norway, Sweden, Poland, Germany, the Czech Republic and Australia. Confirmation that the Australian patient is of German ancestry, together with the Northern and Central European origin of most of the other patients, suggests that the 4143insA mutation has a common genetic background.We established ADAMTS 13 haplotypes by analyzing 17 polymorphic intragenic markers.The haplotypes linked to 4143insA were identical in all informative families. Three novel candidate mutations, C347S, P67IL and RI060W, as well as the known mutation R507Q, were also identified during the course of the study.We conclude that 4143insA has a common genetic background and is frequent among patients with hereditary ADAMTS 13 deficiency in Northern and Central European countries.
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| 2. |
- Anande, Govardhan, et al.
(författare)
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RNA Splicing Alterations Induce a Cellular Stress Response Associated with Poor Prognosis in Acute Myeloid Leukemia
- 2020
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Ingår i: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 26:14, s. 3597-3607
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: RNA splicing is a fundamental biological process that generates protein diversity from a finite set of genes. Recurrent somatic mutations of splicing factor genes are common in some hematologic cancers but are relatively uncommon in acute myeloid leukemia (AML, < 20% of patients). We examined whether RNA splicing differences exist in AML, even in the absence of splicing factor mutations.Experimental Design: We developed a bioinformatics pipeline to study alternative RNA splicing in RNA-sequencing data from large cohorts of patients with AML.Results: We have identified recurrent differential alternative splicing between patients with poor and good prognosis. These splicing events occurred even in patients without any discernible splicing factor mutations. Alternative splicing recurrently occurred in genes with specific molecular functions, primarily related to protein translation. Developing tools to predict the functional impact of alternative splicing on the translated protein, we discovered that approximately 45% of the splicing events directly affected highly conserved protein domains. Several splicing factors were themselves misspliced and the splicing of their target transcripts were altered. Studying differential gene expression in the same patients, we identified that alternative splicing of protein translation genes in ELNAdv patients resulted in the induction of an integrated stress response and upregulation of inflammation-related genes. Finally, using machine learning techniques, we identified a splicing signature of four genes which refine the accuracy of existing risk prognosis schemes and validated it in a completely independent cohort.Conclusions: Our discoveries therefore identify aberrant alternative splicing as a molecular feature of adverse AML with clinical relevance.
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| 3. |
- Kumar, Praveen, et al.
(författare)
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HMGA2 promotes long-term engraftment and myeloerythroid differentiation of human hematopoietic stem and progenitor cells
- 2019
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Ingår i: Blood Advances. - : American Society of Hematology. - 2473-9529 .- 2473-9537. ; 3:4, s. 681-691
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Tidskriftsartikel (refereegranskat)abstract
- Identification of determinants of fate choices in hematopoietic stem cells (HSCs) is essential to improve the clinical use of HSCs and to enhance our understanding of the biology of normal and malignant hematopoiesis. Here, we show that high-mobility group AT hook 2 (HMGA2), a nonhistone chromosomal-binding protein, is highly and preferentially expressed in HSCs and in the most immature progenitor cell subset of fetal, neonatal, and adult human hematopoiesis. Knockdown of HMGA2 by short hairpin RNA impaired the long-term hematopoietic reconstitution of cord blood (CB)-derived CB CD34+ cells. Conversely, overexpression of HMGA2 in CB CD34+ cells led to overall enhanced reconstitution in serial transplantation assays accompanied by a skewing toward the myeloerythroid lineages. RNA-sequencing analysis showed that enforced HMGA2 expression in CD34+ cells induced gene-expression signatures associated with differentiation toward megakaryocyte-erythroid and myeloid lineages, as well as signatures associated with growth and survival, which at the protein level were coupled with strong activation of AKT. Taken together, our findings demonstrate a key role of HMGA2 in regulation of both proliferation and differentiation of human HSPCs.
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| 4. |
- Putri, Givanna H., et al.
(författare)
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Analysing high-throughput sequencing data in Python with HTSeq 2.0
- 2022
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Ingår i: Bioinformatics. - : Oxford University Press (OUP). - 1367-4803 .- 1367-4811. ; 38:10, s. 2943-2945
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Tidskriftsartikel (refereegranskat)abstract
- HTSeq 2.0 provides a more extensive application programming interface including a new representation for sparse genomic data, enhancements for htseq-count to suit single-cell omics, a new script for data using cell and molecular barcodes, improved documentation, testing and deployment, bug fixes and Python 3 support.
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| 5. |
- Thoms, Julie A.I., et al.
(författare)
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Disruption of a GATA2-TAL1-ERG regulatory circuit promotes erythroid transition in healthy and leukemic stem cells
- 2021
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 138:16, s. 1441-1455
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Tidskriftsartikel (refereegranskat)abstract
- Changes in gene regulation and expression govern orderly transitions from hematopoietic stem cells to terminally differentiated blood cell types. These transitions are disrupted during leukemic transformation, but knowledge of the gene regulatory changes underpinning this process is elusive. We hypothesized that identifying core gene regulatory networks in healthy hematopoietic and leukemic cells could provide insights into network alterations that perturb cell state transitions. A heptad of transcription factors (LYL1, TAL1, LMO2, FLI1, ERG, GATA2, and RUNX1) bind key hematopoietic genes in human CD34+ hematopoietic stem and progenitor cells (HSPCs) and have prognostic significance in acute myeloid leukemia (AML). These factors also form a densely interconnected circuit by binding combinatorially at their own, and each other's, regulatory elements. However, their mutual regulation during normal hematopoiesis and in AML cells, and how perturbation of their expression levels influences cell fate decisions remains unclear. In this study, we integrated bulk and single-cell data and found that the fully connected heptad circuit identified in healthy HSPCs persists, with only minor alterations in AML, and that chromatin accessibility at key heptad regulatory elements was predictive of cell identity in both healthy progenitors and leukemic cells. The heptad factors GATA2, TAL1, and ERG formed an integrated subcircuit that regulates stem cell-to-erythroid transition in both healthy and leukemic cells. Components of this triad could be manipulated to facilitate erythroid transition providing a proof of concept that such regulatory circuits can be harnessed to promote specific cell-type transitions and overcome dysregulated hematopoiesis.
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| 6. |
- Unnikrishnan, Ashwin, et al.
(författare)
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A quantitative proteomics approach identifies ETV6 and IKZF1 as new regulators of an ERG-driven transcriptional network
- 2016
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Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 1362-4962 .- 0305-1048. ; 44:22, s. 10644-10661
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Tidskriftsartikel (refereegranskat)abstract
- Aberrant stem cell-like gene regulatory networks are a feature of leukaemogenesis. The ETS-related gene (ERG), an important regulator of normal haematopoiesis, is also highly expressed in T-ALL and acute myeloid leukaemia (AML). However, the transcriptional regulation of ERG in leukaemic cells remains poorly understood. In order to discover transcriptional regulators of ERG, we employed a quantitative mass spectrometry-based method to identify factors binding the 321 bp ERG +85 stem cell enhancer region in MOLT-4 T-ALL and KG-1 AML cells. Using this approach, we identified a number of known binders of the +85 enhancer in leukaemic cells along with previously unknown binders, including ETV6 and IKZF1. We confirmed that ETV6 and IKZF1 were also bound at the +85 enhancer in both leukaemic cells and in healthy human CD34+ haematopoietic stem and progenitor cells. Knockdown experiments confirmed that ETV6 and IKZF1 are transcriptional regulators not just of ERG, but also of a number of genes regulated by a densely interconnected network of seven transcription factors. At last, we show that ETV6 and IKZF1 expression levels are positively correlated with expression of a number of heptad genes in AML and high expression of all nine genes confers poorer overall prognosis.
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| 7. |
- Woll, Petter S, et al.
(författare)
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Myelodysplastic Syndromes Are Propagated by Rare and Distinct Human Cancer Stem Cells In Vivo.
- 2014
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Ingår i: Cancer Cell. - : Elsevier BV. - 1878-3686 .- 1535-6108. ; 25:6, s. 794-808
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Tidskriftsartikel (refereegranskat)abstract
- Evidence for distinct human cancer stem cells (CSCs) remains contentious and the degree to which different cancer cells contribute to propagating malignancies in patients remains unexplored. In low- to intermediate-risk myelodysplastic syndromes (MDS), we establish the existence of rare multipotent MDS stem cells (MDS-SCs), and their hierarchical relationship to lineage-restricted MDS progenitors. All identified somatically acquired genetic lesions were backtracked to distinct MDS-SCs, establishing their distinct MDS-propagating function in vivo. In isolated del(5q)-MDS, acquisition of del(5q) preceded diverse recurrent driver mutations. Sequential analysis in del(5q)-MDS revealed genetic evolution in MDS-SCs and MDS-progenitors prior to leukemic transformation. These findings provide definitive evidence for rare human MDS-SCs in vivo, with extensive implications for the targeting of the cells required and sufficient for MDS-propagation.
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