scholarly journals A Nationwide Study of GATA2 Deficiency in Norway—the Majority of Patients Have Undergone Allo-HSCT

2021 ◽  
Author(s):  
Silje F. Jørgensen ◽  
Jochen Buechner ◽  
Anders E. Myhre ◽  
Eivind Galteland ◽  
Signe Spetalen ◽  
...  
Keyword(s):  
Clinical Information ◽  
Clinical Genetic ◽  
Data Set ◽  
Hematopoietic Stem ◽  
In Situ Carcinoma ◽  
Asymptomatic Patients ◽  
Gata2 Deficiency ◽  
Considerable Morbidity ◽  
Myeloid Neoplasia ◽  
Clinical Awareness

Abstract Purpose GATA2 deficiency is a rare primary immunodeficiency that has become increasingly recognized due to improved molecular diagnostics and clinical awareness. The only cure for GATA2 deficiency is allogeneic hematopoietic stem cell transplantation (allo-HSCT). The inconsistency of genotype–phenotype correlations makes the decision regarding “who and when” to transplant challenging. Despite considerable morbidity and mortality, the reported proportion of patients with GATA2 deficiency that has undergone allo-HSCT is low (~ 35%). The purpose of this study was to explore if detailed clinical, genetic, and bone marrow characteristics could predict end-point outcome, i.e., death and allo-HSCT. Methods All medical genetics departments in Norway were contacted to identify GATA2 deficient individuals. Clinical information, genetic variants, treatment, and outcome were subsequently retrieved from the patients’ medical records. Results Between 2013 and 2020, we identified 10 index cases or probands, four additional symptomatic patients, and no asymptomatic patients with germline GATA2 variants. These patients had a diverse clinical phenotype dominated by cytopenia (13/14), myeloid neoplasia (10/14), warts (8/14), and hearing loss (7/14). No valid genotype–phenotype correlations were found in our data set, and the phenotypes varied also within families. We found that 11/14 patients (79%), with known GATA2 deficiency, had already undergone allo-HSCT. In addition, one patient is awaiting allo-HSCT. The indications to perform allo-HSCT were myeloid neoplasia, disseminated viral infection, severe obliterating bronchiolitis, and/or HPV-associated in situ carcinoma. Two patients died, 8 months and 7 years after allo-HSCT, respectively. Conclusion Our main conclusion is that the majority of patients with symptomatic GATA2 deficiency will need allo-HSCT, and a close surveillance of these patients is important to find the “optimal window” for allo-HSCT. We advocate a more offensive approach to allo-HSCT than previously described.

Computer-Aided Diagnosis in Jaundice: Comparison of Knowledge-based and Probabilistic Approaches

1996 ◽  
Vol 35 (01) ◽  
pp. 41-51 ◽  
Author(s):  
F. Molino ◽  
D. Furia ◽  
F. Bar ◽  
S. Battista ◽  
N. Cappello ◽  
...  
Keyword(s):  
Clinical Presentation ◽  
Clinical Information ◽  
Diagnostic Value ◽  
Clinical Findings ◽  
Clinical Documentation ◽  
Data Set ◽  
Knowledge Based ◽  
Number Of Patients ◽  
Support Tools ◽  
Aided Diagnosis

AbstractThe study reported in this paper is aimed at evaluating the effectiveness of a knowledge-based expert system (ICTERUS) in diagnosing jaundiced patients, compared with a statistical system based on probabilistic concepts (TRIAL). The performances of both systems have been evaluated using the same set of data in the same number of patients. Both systems are spin-off products of the European project Euricterus, an EC-COMACBME Project designed to document the occurrence and diagnostic value of clinical findings in the clinical presentation of jaundice in Europe, and have been developed as decision-making tools for the identification of the cause of jaundice based only on clinical information and routine investigations. Two groups of jaundiced patients were studied, including 500 (retrospective sample) and 100 (prospective sample) subjects, respectively. All patients were independently submitted to both decision-support tools. The input of both systems was the data set agreed within the Euricterus Project. The performances of both systems were evaluated with respect to the reference diagnoses provided by experts on the basis of the full clinical documentation. Results indicate that both systems are clinically reliable, although the diagnostic prediction provided by the knowledge-based approach is slightly better.

scholarly journals 735. Trends and Cost Analysis of Aspergillus Galactomannan testing at a Tertiary Medical Center

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S417-S417
Author(s):  
Peyton R Treutel ◽  
Anna Carr ◽  
Pradeep Bathina
Keyword(s):  
Stem Cell ◽  
Hematologic Malignancy ◽  
Medical Center ◽  
Organ Transplant ◽  
The Self ◽  
Solid Organ ◽  
Data Set ◽  
Hematopoietic Stem ◽  
Patients Âgés ◽  
Optical Density Index

Abstract Background Aspergillus is a fungus spread by inhalation of spores that can lead to invasive (IA), chronic, or allergic aspergillosis. Risk factors for IA include neutropenia, hematological malignancy, allogenic stem cell (HSCT) or solid organ transplant, severe immunodeficiency, or prolonged steroid use. An alternative to invasive tissue sampling, the serum Galactomannan (AGM) test detects a polysaccharide cell wall component of Aspergillus and can be used to determine a probable diagnosis of IA. Accuracy of AGM is related to disease burden and thus has the highest sensitivity and specificity in patients with hematologic malignancy or Hematopoietic stem cell transplantation (HSCT) at 70-82% and 86-92%, respectively. Studies have shown sensitivity to decline in other populations, with solid organ transplants as low as 20%. Methods We performed a retrospective study of all patients who received the AGM test at UMMC from January 3, 2013 to December 31, 2019. Patient Cohort Explorer was used to obtain de-identified patient data from EPIC. We obtained the number of encounters and patients on whom the AGM test was performed along with other variables. Billing offices provided the self-pay cost per AGM test. Results A total of 6,404 AGM tests were performed on 2,126 patients during 4,315 encounters in the study period. With a total of 499, 574, 984, 1140, 851, 1175 and 1181 tests done respectively from 2013 to 2019, a increasing trend was noted. The patients ages ranged from 1 to 89 with a median age of 52 years. A total of 3,055 tests were ordered in females, and 3,349 were ordered in males. At a cut off value (optical density index) of > 0.5, 183 AGM tests resulted positive in 108 patients and at a cut of > 1.0, 113 tests are positive in 70 patients. The rate of a positive AGM tests at > 0.5 was at 2.85% and at > 1.0 was at 1.76% over the study period. With the self-pay cost of each test at $134.54 in 2019 USD, the total cost of 6,404 tests was $861,594.16. Conclusion To our knowledge this data set constitutes the largest sample size of AGM testing. From our data, it seems that the rate of ordering this test has increased yearly. Relatively low percentage of these tests are positive, suggesting that it is most likely a large amount of these tests could have been ordered inappropriately or in the wrong clinical context. Disclosures All Authors: No reported disclosures

Nocna napadowa hemoglobinuria u dzieci jako przykład rzadkich schorzeń ukrywających się pod różnymi maskami rozpoznań klinicznych. Dylematy kliniczne, etyczne i społeczne rozpoznawania chorób ultrarzadkich na kanwie przypadku

2019 ◽  
Vol 23 (1) ◽  
Author(s):  
Marek W. Karwacki ◽  
Anna Adamowicz-Salach ◽  
Michał Matysiak ◽  
Aleksandra Pankiewicz
Keyword(s):  
Bone Marrow Failure ◽  
Surface Proteins ◽  
Hematopoietic Stem ◽  
Ethical Problems ◽  
Myeloid Progenitor ◽  
Myeloid Progenitor Cells ◽  
Proper Diagnosis ◽  
The Subject ◽  
The One ◽  
Clinical Awareness

Paroxysmal nocturnal hemoglobinuria (PNH) is an extremely rare disease in children resulted from clonal hematopoietic stem cell proliferation triggered by acquired somatic mutation of the PIGA gene. As a consequence, a deficiency of surface proteins, e.g. responsible for protection of the untouched myeloid progenitor cells from the complement aggression, is observed. It is characterized by intra and extravascular hemolysis, various degrees of bone marrow failure and a tendency to thrombophilia with multifocal thrombosis, especially affecting visceral circulation. The aim of the case description concerning a 16 years old boy with more than 4 years delay in proper diagnosis resulted from the abdominal mask of PNH, is to draw the attention of pediatrician to identifiable diagnostic problems, when the one has had to face with rare diseases. Many, even well-known and described disorders in adults had an unexpected course in children with significant differences resulting in various clinical masks leading to misdiagnosis. Overlapping symptomatology between popular and unique disorders of childhood may be responsible for misdiagnosis as well, what demand the specific clinical awareness and response. The other, but not less important aspect of presented case report, describing such a unique disease of childhood treated with one of the most expensive therapy in the world, is important question of the ethical and socio-economic borders of modern medical therapies. All the aspect of clinical and ethical problems comprises the subject of this publication.

scholarly journals Mendelian randomization analysis of celiac GWAS reveals a blood expression signature with diagnostic potential in absence of gluten consumption

2019 ◽  
Vol 28 (18) ◽  
pp. 3037-3042 ◽  
Author(s):  
Nora Fernandez-Jimenez ◽  
Jose Ramon Bilbao
Keyword(s):  
Genome Wide Association Study ◽  
Mononuclear Cells ◽  
Mendelian Randomization ◽  
Correct Diagnosis ◽  
Peripheral Blood Mononuclear ◽  
Data Set ◽  
Diagnostic Potential ◽  
Specificity And Sensitivity ◽  
Asymptomatic Patients ◽  
Causal Genes

Abstract Celiac disease (CeD) is an immune-mediated enteropathy with a strong genetic component where the main environmental trigger is dietary gluten, and currently a correct diagnosis of the disease is impossible if gluten-free diet (GFD) has already been started. We hypothesized that merging different levels of genomic information through Mendelian randomization (MR) could help discover genetic biomarkers useful for CeD diagnosis. MR was performed using public databases of expression quantitative trait loci (QTL) and methylation QTL as exposures and the largest CeD genome-wide association study conducted to date as the outcome, in order to identify potential causal genes. As a result, we identified UBE2L3, an ubiquitin ligase located in a CeD-associated region. We interrogated the expression of UBE2L3 in an independent data set of peripheral blood mononuclear cells (PBMCs) and found that its expression is altered in CeD patients on GFD when compared to non-celiac controls. The relative expression of UBE2L3 isoforms predicts CeD with 100% specificity and sensitivity and could be used as a diagnostic marker, especially in the absence of gluten consumption. This approach could be applicable to other diseases where diagnosis of asymptomatic patients can be complicated.

scholarly journals Exploring Integrative Analysis Using the BioMedical Evidence Graph

2020 ◽  
pp. 147-159 ◽  
Author(s):  
Adam Struck ◽  
Brian Walsh ◽  
Alexander Buchanan ◽  
Jordan A. Lee ◽  
Ryan Spangler ◽  
...  
Keyword(s):  
Cancer Biology ◽  
Drug Response ◽  
Clinical Information ◽  
Application Programming Interface ◽  
Knowledge Bases ◽  
Heterogeneous Data ◽  
Integrative Analysis ◽  
Data Set ◽  
Evidence Graph ◽  
Reference Knowledge

PURPOSE The analysis of cancer biology data involves extremely heterogeneous data sets, including information from RNA sequencing, genome-wide copy number, DNA methylation data reporting on epigenetic regulation, somatic mutations from whole-exome or whole-genome analyses, pathology estimates from imaging sections or subtyping, drug response or other treatment outcomes, and various other clinical and phenotypic measurements. Bringing these different resources into a common framework, with a data model that allows for complex relationships as well as dense vectors of features, will unlock integrated data set analysis. METHODS We introduce the BioMedical Evidence Graph (BMEG), a graph database and query engine for discovery and analysis of cancer biology. The BMEG is unique from other biologic data graphs in that sample-level molecular and clinical information is connected to reference knowledge bases. It combines gene expression and mutation data with drug-response experiments, pathway information databases, and literature-derived associations. RESULTS The construction of the BMEG has resulted in a graph containing > 41 million vertices and 57 million edges. The BMEG system provides a graph query–based application programming interface to enable analysis, with client code available for Python, Javascript, and R, and a server online at bmeg.io. Using this system, we have demonstrated several forms of cross–data set analysis to show the utility of the system. CONCLUSION The BMEG is an evolving resource dedicated to enabling integrative analysis. We have demonstrated queries on the system that illustrate mutation significance analysis, drug-response machine learning, patient-level knowledge-base queries, and pathway level analysis. We have compared the resulting graph to other available integrated graph systems and demonstrated the former is unique in the scale of the graph and the type of data it makes available.

scholarly journals Sequencing of RNA in single cells reveals a distinct transcriptome signature of hematopoiesis in GATA2 deficiency

2020 ◽  
Vol 4 (12) ◽  
pp. 2702-2716
Author(s):  
Zhijie Wu ◽  
Shouguo Gao ◽  
Carrie Diamond ◽  
Sachiko Kajigaya ◽  
Jinguo Chen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Stem Cells ◽  
Chromosomal Abnormalities ◽  
Single Cells ◽  
Trisomy 8 ◽  
Broad Perspective ◽  
Hematopoietic Stem ◽  
Gata2 Deficiency ◽  
Additional Chromosomal Abnormalities

Abstract Constitutional GATA2 deficiency caused by heterozygous germline GATA2 mutations has a broad spectrum of clinical phenotypes, including systemic infections, lymphedema, cytopenias, and myeloid neoplasms. Genotype–phenotype correlation is not well understood mechanistically in GATA2 deficiency. We performed whole transcriptome sequencing of single hematopoietic stem and progenitor cells from 8 patients, who had pathogenic GATA2 mutations and myelodysplasia. Mapping patients’ cells onto normal hematopoiesis, we observed deficiency in lymphoid/myeloid progenitors, also evident from highly constrained gene correlations. HSPCs of patients exhibited distinct patterns of gene expression and coexpression compared with counterparts from healthy donors. Distinct lineages showed differently altered transcriptional profiles. Stem cells in patients had dysregulated gene expression related to apoptosis, cell cycle, and quiescence; increased expression of erythroid/megakaryocytic priming genes; and decreased lymphoid priming genes. The prominent deficiency in lympho-myeloid lineages in GATA2 deficiency appeared at least partly due to the expression of aberrant gene programs in stem cells prior to lineage commitment. We computationally imputed cells with chromosomal abnormalities and determined their gene expression; DNA repair genes were downregulated in trisomy 8 cells, potentially rendering these cells vulnerable to second-hit somatic mutations and additional chromosomal abnormalities. Cells with complex cytogenetic abnormalities showed defects in genes related to multilineage differentiation and cell cycle. Single-cell RNA sequencing is powerful in resolving transcriptomes of cell subpopulations despite a paucity of cells in marrow failure. Our study discloses previously uncharacterized transcriptome signatures of stem cells and progenitors in GATA2 deficiency, providing a broad perspective of potential mechanisms by which germline mutations modulate early hematopoiesis in a human disease. This trial was registered at www.clinicaltrials.gov as NCT01905826, NCT01861106, and NCT00001620.

3D Genomics of Acute Meyloid Leukemia Reveals the Imbalance between DNA Methylation Canyon Interactions and Leukemic Specific Enhancer Network Interactions

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 45-45
Author(s):  
Xiaotian Zhang ◽  
Xue Qing David Wang ◽  
Haley Gore ◽  
Pamela Himadewi ◽  
Fan Feng ◽  
...  
Keyword(s):  
Dna Methylation ◽  
High Resolution ◽  
Cell Lines ◽  
Leukemia Cell ◽  
Chromatin Organization ◽  
Data Set ◽  
Hematopoietic Stem ◽  
Leukemia Cell Lines ◽  
Hyperacetylated Domains ◽  
Primary Leukemia

Changes in 3D chromatin organization like enhancer hijacking are believed to the driver for disease development like leukemia. Here we performed high-resolution HiC assays on primary acute myeloid leukemia (AML) samples and cell lines to dissect the abnormal 3D chromatin organization in AML. Our data set covers 5 AML samples and 3 AML cell lines. This dataset includes the common genetic abnormalities in AML: MLL-rearrangement, NPM1 mutation, RUNX1 mutation, and IDH1/TET2 mutations. We have recently generated high-resolution map for normal human hematopoietic stem cells (HSC) (Zhang et al. Mole Cell. 2020). In comparison with the HSC 3D chromatin organization, we found TADs and loops are very stable in both primary leukemia samples and cell lines. Less than 5% of all TADs in HSC fuse in AML, mimicking the enhancer hijacking scenario. These fusion events do not cause the gene expression changes of genes in the fused TAD. Interestingly, in TET2 or IDH1 mutated AML blast, two-fold more TAD fusion events occurred in primary AML blast in comparison with RUNX1 and MLL-r leukemia, with a loss in the CTCF sites on the TAD fusion break point. We previously found in HSC, the Polycomb marked DNA methylation Canyons (DMC) form multi-Mb size long-range interactions. DMC interactions in general decrease in primary AMLs. AMLs with IDH1 or TET2 mutations shows the biggest reduction in DMC interactions. Hypermethylation in the DMCs is observed in the AML samples with IDH1/2 or TET2 mutations, suggesting DNA methylation level in DMCs controls DMC 3D interactions directly. In leukemia cell lines, the DMC interactions almost disappear, with further hypermethylation in DMCs. Compared with normal HSC, we found in AML, the AML-specific H3K27ac marked regions form leukemia specific loops and transcription stripes in both cell lines and primary samples. Particularly in MLL-r primary leukemias, we found broad H3K27ac covered, hyperacetylated domains (10kb to 200kb). 22 such hyperacetylated domains were identified and associated with leukemogenic genes such as SATB1, ZEB2 and HOXA. All these domains formed distinct 3D micro TAD in the MLL-r primary leukemia in comparison with the HSPC, and CTCFs are not located at the border of these domains. Taken together, suggest active leukemia specific transcription created new 3D genomic interactions which is independent of cohesion-CTCF mediated loop extrusion. Interestingly, in HOXA cluster, we found a geneless DMC 1.3MB upstream of HOXA switched from Polycomb binding site to active enhancer site in the leukemia cells. By applying CRISPR/Cas9 editing, we found this canyon is essential for survival of HOXA high expressing leukemia cell lines like OCI-AML3 and MV4:11. In summary, we found the 3D chromatin organization in human leukemia significantly alters in two opposite way 1. The significant loss of Polycomb marked DMC interactions caused by the DNA hypermethylation and 2. The leukemic specific hyperacetylated domains form its own distinct micro TAD and stripes in the 3D chromatin organization. Disclosures No relevant conflicts of interest to declare.

Risk Factors Associated with VOD with RIC and MAC Hematopoietic Stem Cell Transplant and the Early Estimation of VOD

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4315-4315
Author(s):  
Shoichi Nagakura ◽  
Tetsuyuki Kiyokawa ◽  
Michihiro Hidaka ◽  
Takahiro Yano ◽  
Kazutaka Sunami ◽  
...  
Keyword(s):  
Risk Factors ◽  
Goodness Of Fit ◽  
Time Course ◽  
Laboratory Data ◽  
P Value ◽  
Cell Transplant ◽  
Data Set ◽  
Hematopoietic Stem ◽  
Post Transplant ◽  
Factors Associated

Abstract BACKGROUND: Despite recent increase of reduced intensity conditioning (RIC) transplantation, mortality rates after RIC and myeloabrative conditioning (MAC) HSCT remain high and hepatic veno-occlusive disease (VOD) cannot accurately predicted. OBJECTIVE: To determine the value of risk factors associated with the development of VOD after allergenic HSCT with RIC and MAC. Estimating VOD based on clinical factors may further improve results of allogenic HSCT. PATIENTS AND METHODS: A retrospective review of 415 consecutive allogenic HSCT was performed with attention to VOD, pre-transplant factors and laboratory data in five hematopoietic cell transplantation centers between 2000 and 2005. Patients underwent transplantation with MAC (n=247) or RIC (n=168). Main outcomes and risk factors were analyzed in multivariable analyses (a logistic regression model) with RIC and MAC. Three kind of laboratory data set, pre-transplant (day −10), post-transplant (day 20) and differences from pre-transplant to post-transplantation were analyzed. RESULTS: VOD occurred in 65 of 415(15.7%) transplant recipients; 40 of 247(16.1%) with MAC and 25 of 168(14.9%) with RIC. Multivariate analyses identified risk factors with the development of VOD with MAC (albumin level, creatinine level) and with RIC (HCT-CI, number of prior chemotherapy regimen, ALT) in pre-transplant laboratory data set. The risk factors of VOD were identified in post-transplant and differences (Table). The Akaike’s information criterion (AIC) of risk factors with differences was better than with the post-transplant. CONCLUSION: Our results provided risk factors of VOD with MAC and RIC. The estimation of VOD before transplantation may be useful for the selection of conditioning regimens. Differences of laboratory data with the time course of transplant may be useful for the early diagnosis of VOD. MAC Pre-transpant data Post-transplant data Differences data OR P-Value OR P-Value OR P-Value Age - - 0.945 0.0090 - - Alb 0.290 0.0125 - - - - Cr 10.204 0.0307 1.786 0.0039 1.984 0.0139 TPro - - 0 358 0.0019 - - TBi I - - 1.385 0.0027 1.314 0.0037 Ara-C - - 5.000 0.0139 goodness of fit AIC 106.727 126.499 86.931 RIC Pre-transpant data Post-transplant data Differences data OR P-Value OR P-Value OR P-Value Sex - - 3.401 0.0446 - - HCTCI 3.922 0.0050 2.000 0.0123 - - ImpScore 2.000 0.0314 - - - - TPro - - 0.366 0.0091 - - TBi I - - 1.675 0.0042 2.273 0.0004 ALT 0.969 0.0432 - - - - CY - - - - 5.682 0.0447 goodness of fit AIC 61.552 91.09 52.808

A-To-I RNA Editing By ADAR1 Is Essential For Hematopoiesis

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1199-1199 ◽  
Author(s):  
Brian Liddicoat ◽  
Robert Piskol ◽  
Alistair Chalk ◽  
Miyoko Higuchi ◽  
Peter Seeburg ◽  
...  
Keyword(s):  
Gene Expression ◽  
Rna Editing ◽  
Fetal Liver ◽  
Expression Profiles ◽  
In Utero ◽  
Tamoxifen Treatment ◽  
Rna Seq ◽  
Data Set ◽  
Hematopoietic Stem

Abstract The role of RNA and its regulation is becoming increasingly appreciated as a vital component of hematopoietic development. RNA editing by members of the Adenosine Deaminase Acting on RNA (ADAR) gene family is a form of post-transcriptional modification which converts genomically encoded adenosine to inosine (A-to-I) in double-stranded RNA. A-to-I editing by ADAR directly converts the sequence of the RNA substrate and can alter the structure, function, processing, and localization of the targeted RNA. ADAR1 is ubiquitously expressed and we have previously described essential roles in the development of hematopoietic and hepatic organs. Germline ablation of murine ADAR1 results in a significant upregulation of interferon (IFN) stimulated genes and embryonic death between E11.5 and E12.5 associated with fetal liver disintegration and failed hemopoiesis. To determine the biological importance of A-to-I editing by ADAR1, we generated an editing dead knock-in allele of ADAR1 (ADAR1E861A). Mice homozygous for the ADAR1E861A allele died in utero at ∼E13.5. The fetal liver (FL) was small and had significantly lower cellularity than in controls. Analysis of hemopoiesis demonstrated increased apoptosis and a loss of hematopoietic stem cells (HSC) and all mature lineages. Most notably erythropoiesis was severely impaired with ∼7-fold reduction across all erythrocyte progenitor populations compared to controls. These data are consistent with our previous findings that ADAR1 is essential for erythropoiesis (unpublished data) and suggest that the ADAR1E861A allele phenocopies the null allele in utero. To assess the requirement of A-to-I editing in adult hematopoiesis, we generated mice where we could somatically delete the wild-type ADAR1 allele and leave only ADAR1E861A expressed in HSCs (hScl-CreERAdar1fl/E861A). In comparison to hScl-CreERAdar1fl/+ controls, hScl-CreERAdar1fl/E861A mice were anemic and had severe leukopenia 20 days post tamoxifen treatment. Investigation of marrow hemopoiesis revealed a significant loss of all cells committed to the erythroid lineage in hScl-CreERAdar1fl/E861A mice, despite having elevated phenotypic HSCs. Upon withdrawal of tamoxifen diet, all blood parameters were restored to control levels within 12 weeks owing to strong selection against cells expressing only the ADAR1E861A allele. To understand the mechanism through which ADAR1 mediated A-to-I editing regulates hematopoiesis, RNA-seq was performed. Gene expression profiles showed that a loss of ADAR1 mediated A-to-I editing resulted in a significant upregulation of IFN signatures, consistent with the gene expression changes in ADAR1 null mice. To define substrates of ADAR1 we assessed A-to-I mismatches in the RNA-seq data sets. 3,560 previously known and 353 novel A-to-I editing sites were identified in our data set. However, no single editing substrate discovered could account for the IFN signature observed or the lethality of ADAR1E861A/E861A mice. These results demonstrate that ADAR1 mediated A-to-I editing is essential for the maintenance of both fetal and adult hemopoiesis in a cell-autonomous manner and a key suppressor of the IFN response in hematopoiesis. Furthermore the ADAR1E861A allele demonstrates the essential role of ADAR1 in vivo is A-to-I editing. Disclosures: Hartner: TaconicArtemis: Employment.

Leukemia Cell Infiltration Causes Defective Erythropoiesis Partially through MIP-1alpha

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1185-1185
Author(s):  
Yajie Wang ◽  
Sha Hao ◽  
Ping Lu ◽  
Hui Cheng ◽  
Yuemin Gong ◽  
...  
Keyword(s):  
Stem Cells ◽  
Blood Cells ◽  
Erythroid Differentiation ◽  
Inhibitory Effect ◽  
Gene Set Enrichment Analysis ◽  
Cell Infiltration ◽  
Down Regulation ◽  
Data Set ◽  
Western Blots ◽  
Hematopoietic Stem

Abstract Leukemia often results in severe anemia, which may significantly contributes to mortality and morbidity of the patients. However, the mechanisms underlying the insufficient erythropoiesis in leukemia have been poorly understood. In this study, with our recently established non-irradiated MLL-AF9 acute myeloid leukemia (AML) murine model (Cheng H et al, Blood 2015), we observed a significant decrease in hemoglobin and red blood cells (RBCs) of Peripheral blood (PB) in the leukemic mice (n=6 per group, p=0.0122 vs p=0.0003). The absolute numbers of the erythroblasts at different stages (Pro Es, Ery.A, Ery.B, Ery.C) in bone marrow (BM) were also reduced. Consistently, by gene set enrichment analysis (GSEA) of microarray data of LKS+ cells (GSE52506 ) from leukemic mice, we found significant down-regulation of erythroid differentiation related genes such as GATA1, FOG-1, LMO2 and KLF1. These genes were more significantly inhibited in megakaryocytic-erythroid progenitors (MEPs) and Pro Es from the leukemic mice. Notably, the MEPs were the most reduced subset among all the committed hematopoietic progenitor cells (HPCs) during leukemia progression (90% decrease compared to control, p = 0.0007). MEPs were gradually accumulated in the G0 phase (from 22% to 70%, p<0.001). In contrast, erythroblasts (Pro Es, Ery.A, Ery.B) were more cycling (G1/S/G2/M) in leukemic mice and the proportions of Annexin V+ cells in erythroblasts but not in MEPs were also increased during leukemia development. Colony-forming cell (CFC) assays revealed that BM plasma of leukemia mice exerted an inhibitory effect on both BFU-Es and CFU-Es of BM mononuclear cells (BMMNCs) but not on other types of colonies (40% decrease for CFU-Es, 60% decrease for BFU-Es, p<0.001). Consistently, BM plasma of AML patients could also reduce the yield of BFU-Es and CFU-Es from CD34+ cord blood cells (n=7, p=0.006). To determine which cytokines may be responsible for the inhibitory effect, we collected serum and BM plasma from control and leukemic mice for cytokine array analysis. Among the elevated cytokines, MIP-1alpha was previously reported to be up-regulated in leukemic stem cells and its higher expression was found in the majority of patients with leukemia and a subset of patients with lymphoma and myeloma according to the Oncomine data set. We also confirmed it in a cohort of untreated AML patients (n=32). Importantly, AML patients with higher expression of MIP-1alpha showed reduced survival time (median=13.08 months) compared with the patients with lower expression (median=25.86 months) based on the leukemia-gene-atlas (LGA) analysis (n=72). By the CFC assay and single cell culture with different subsets of hematopoietic stem cells (HSCs) and HPCs, MIP-1alpha was able to largely mimic the inhibitory effect on the erythroid differentiation at both stem cell and progenitor cell levels. Mechanistically, we observed higher expression of MIP-1alpha receptor CCR1 in HSCs, MEPs and erythroblasts than CCR5. Administration of CCR1 antagonist, BX471 could partially recover the yield of erythroid colonies after treatment of MIP-1alpha or leukemia BM plasma. An increase of phosphorylation of p38 (phos p38) and resulted down-regulation of GATA1 after MIP-1alpha treatment were documented by Western blots and immunostaining. In summary, our results demonstrate that leukemic cell infiltration causes severe inhibition of erythropoiesis largely at different erythroid precursor levels and this inhibitory effect is at least partially medicated by elevated MIP-1alpha level via CCR1-p38 activation in the leukemic microenvironment. Disclosures No relevant conflicts of interest to declare.

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