scholarly journals The Translocation t(7;12)(q36;p13) Induces Myeloid Leukemia in Immuno-Compromised but Not Immunocompetent Mice

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2707-2707
Author(s):  
Ahmed Waraky ◽  
Anders Östlund ◽  
Laleh Arabanian ◽  
Tina Nilsson ◽  
Linda Fogelstrand ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Cells ◽  
Fetal Liver ◽  
Liver Cells ◽  
Adult Bone Marrow ◽  
Leukemia Development ◽  
Fetal Liver Cells ◽  
Immunocompetent Mice ◽  
Adult Bone

Introduction: Non-random cytogenetic aberrations are often involved in the development of AML in children and several aberrations can serve as diagnostic markers, prognosis predictors and impact choice of therapy. In infant AML, a chromosomal translocation t(7;12)(q36;p13) has been found in up to 20-30 % of the cases, making it the second most common genetic aberration in this age group after KMT2A (MLL) rearrangements. Previous studies indicate that this patient group has a dismal prognosis with virtually no event-free survival. Limiting the chances to improve this is the lack of understanding how the t(7;12)(q36;p13) is involved in leukemia development. The translocation leads to a gene fusion MNX1-ETV6 but also to increased MNX1 gene expression. Although both ETV6 and MNX1 are expressed in normal hematopoietic tissues, the role of the fusion protein MNX1-ETV6in the development of AML is not established. Also unclear is whether the driver of leukemogenesis is the fusion itself or the simultaneous overexpression of MNX1. The aim of this study was to assess the transformation capacity and the molecular mechanism of the MNX1-ETV6 fusion and the overexpressed MNX1in vitro and in vivo using murine transplantation models. Material and methods: In a liquid culture system, we introduced the MNX1-ETV6 fusion, MNX1 overexpression, or empty vector into primary murine (C57BL/6) hematopoietic progenitor cells with retroviral transfection. Cells were isolated from either adult bone marrow after 5-FU stimulation, or from fetal liver at E14.5. After enrichment by fluorescence activated cell sorting based on vector co-expressed green/yellow fluorescence protein, transfected cells were used for in vitro experiments and for transplantation into lethally irradiated immunocompetent C57BL/6 mice or sub-lethally irradiated immunocompromised NSGW41 mice. In vitro, cells were assessed with RNA sequencing for gene expression, gamma H2AX assay for DNA double strand brakes, flow cytometry for lineage marker expression, apoptosis and proliferation, and with colony forming unit assay. Results: Upon transplantation, only fetal liver cells transduced with MNX1 or with MNX1-ETV6 fusion were able to induce leukemia in immunocompromised (NSGW41) mice. When MNX1 or MNX1-ETV6 transduced cells were transplanted into immunocompetent mice (C57BL/6) mice, no leukemia development was seen, when either fetal liver or adult bone marrow cells were used for transduction. However, when immunocompromised mice were transplanted with MNX1 or MNX1-ETV6 fusion expressing cells they typically developed signs of disease after 1-2 months and exhibited leukocytosis and elevated blast cells in blood and bone marrow, severe anemia, and enlarged spleens with infiltration of leukemic cells. The cells showed expression of predominantly myeloid markers. In vitro, cells with overexpression of MNX1 or MNX1-ETV6 fusion expression also showed altered lineage differentiation in favor of myeloid differentiation. In addition, MNX1 overexpressing cells, but not MNX1-ETV6 expressing cells, exhibited increased proliferation and colony formation capacity. Both MNX1 overexpressing and MNX1-ETV6 fusion expressing cells showed increased DNA damage as evident from an increased gamma-phosphorylated H2AX in fetal liver and adult bone marrow transduced cells respectively, accompanied with G1 arrest, compared to cells transduced with empty vectors. Both MNX1 and MNX1-ETV6 also led to increased apoptosis in adult bone marrow (3-fold) and to a lesser extent in fetal liver cells (1.5-fold). Results from transcriptome sequencing showed enrichment for specific pathways in G2/M transition of cell cycle in cells transduced by either MNX1or the MNX1-ETV6 fusion. Further investigations to elucidate the molecular mechanisms and pathways through which MNX1 and/or MNX1-ETV6 induce leukemia is ongoing. Conclusions: MNX1 overexpression and MNX1-ETV6 fusion, both characteristics of infant AML with t(7;12)(q36;p13), induced leukemogenic effects in both fetal liver cells and adult bone marrow cells, but could cause a myeloid leukemia only under immunocompromised conditions. This may be of importance for the exclusive prevalence of this AML subtype in young children, with the highest peak during the first six months of life when the immune system is less developed. Disclosures No relevant conflicts of interest to declare.

scholarly journals Production of fetal antigen-bearing erythrocytes in irradiated adult mice grafted with fetal liver hematopoietic cells

Blood ◽  
1979 ◽  
Vol 54 (5) ◽  
pp. 1091-1100 ◽  
Author(s):  
JP Blanchet ◽  
J Samarut ◽  
G Mouchiroud
Keyword(s):  
Bone Marrow ◽  
Environmental Factors ◽  
Bone Marrow Cells ◽  
Fetal Liver ◽  
Liver Cells ◽  
Adult Bone Marrow ◽  
Adult Mice ◽  
Fetal Liver Cells ◽  
Adult Bone ◽  
Fetal Antigen

Abstract The production of erythrocytes bearing an “immature” antigen (Im+ cells) and a “fetal” antigen (Ft+ cells) has been studied in irradiated adult mice grafted either with fetal liver or adult bone marrow cells. The Im+ cells reach a peak 8–11 days after grafting. Ft+ cells are detected only after graft of fetal liver cells; the younger the liver, the greater the number. Since Ft+ cells are rapidly and briefly produced, they could be the progeny of erythroid-committed precursors, which are particularly numerous among fetal liver cells. Environmental factors directing the erythropoietic differentiation towards Ft+ erythrocytes in fetuses or Ft- erythrocytes in adults are proposed.

scholarly journals Production of fetal antigen-bearing erythrocytes in irradiated adult mice grafted with fetal liver hematopoietic cells

Blood ◽  
1979 ◽  
Vol 54 (5) ◽  
pp. 1091-1100
Author(s):  
JP Blanchet ◽  
J Samarut ◽  
G Mouchiroud
Keyword(s):  
Bone Marrow ◽  
Environmental Factors ◽  
Bone Marrow Cells ◽  
Fetal Liver ◽  
Liver Cells ◽  
Adult Bone Marrow ◽  
Adult Mice ◽  
Fetal Liver Cells ◽  
Adult Bone ◽  
Fetal Antigen

The production of erythrocytes bearing an “immature” antigen (Im+ cells) and a “fetal” antigen (Ft+ cells) has been studied in irradiated adult mice grafted either with fetal liver or adult bone marrow cells. The Im+ cells reach a peak 8–11 days after grafting. Ft+ cells are detected only after graft of fetal liver cells; the younger the liver, the greater the number. Since Ft+ cells are rapidly and briefly produced, they could be the progeny of erythroid-committed precursors, which are particularly numerous among fetal liver cells. Environmental factors directing the erythropoietic differentiation towards Ft+ erythrocytes in fetuses or Ft- erythrocytes in adults are proposed.

Allogenic fetal liver cells have a distinct competitive engraftment advantage over adult bone marrow cells when infused into fetal as compared with adult severe combined immunodeficient recipients

Blood ◽  
2002 ◽  
Vol 99 (5) ◽  
pp. 1870-1872 ◽  
Author(s):  
Patricia A. Taylor ◽  
Ronald T. McElmurry ◽  
Christopher J. Lees ◽  
David E. Harrison ◽  
Bruce R. Blazar
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Cells ◽  
Fetal Liver ◽  
Liver Cells ◽  
Adult Bone Marrow ◽  
Stem Cell Source ◽  
Fetal Liver Cells ◽  
Adult Bone ◽  
Better Than ◽  
Marrow Cells

In utero transplantation (IUT) is becoming a viable option for the treatment of various immune and metabolic disorders diagnosed early in gestation. In this study, donor fetal liver cells had a 10-fold competitive engraftment advantage relative to adult bone marrow in allogeneic fetal severe combined immunodeficient (SCID) recipients compared with adult recipients. In contrast, adult bone marrow cells engrafted slightly better than fetal liver cells in allogeneic adult SCID transplant recipients. By using different ratios of fetal and adult cell mixtures, fetal liver cells repopulated 8.2 times better than adult bone marrow cells in fetal recipients, but only 0.8 times as well in adult recipients. Fetal SCID recipients were more permissive to an allogeneic donor graft than adult recipients. These data indicate that the recipient microenvironment may regulate the engraftment efficiency of a given stem cell source and suggest that the use of cord blood should be tested in clinical IUT.

scholarly journals Long-term cultures of murine fetal liver retain very early B lymphoid phenotype.

1984 ◽  
Vol 160 (4) ◽  
pp. 1087-1101 ◽  
Author(s):  
K A Denis ◽  
L J Treiman ◽  
J I St Claire ◽  
O N Witte
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
Heavy Chain ◽  
Bone Marrow Cells ◽  
Fetal Liver ◽  
Liver Cells ◽  
Phenotypic Traits ◽  
Fetal Liver Cells

Long-term cultures of murine fetal liver have been successfully established using a modification of our in vitro bone marrow culture system (14, 15). Fetal liver cells from midgestation BALB/c embryos were plated onto BAB-14 bone marrow stromal cell-adherent layers. After a 3-5 wk period, cell growth began to increase and these cells were expanded in number on fresh feeder layers. The cultured fetal liver cells were lymphoid in morphology, 5-20% cytoplasmic Ig-positive, but less than 1% surface Ig-positive. Southern blot analysis of the cultured fetal liver cells, as well as cultured bone marrow-derived B cells, demonstrated a population with germline Ig heavy chain loci, possibly representing very early B cell precursors. Abelson murine leukemia virus (A-MuLV) clonal transformants of such cultured fetal liver cells had a phenotypic distribution similar to that seen with fresh fetal liver transformants but distinct from those obtained with the transformation of either cultured or fresh bone marrow. All A-MuLV transformants isolated had rearrangements at the mu heavy chain locus of both chromosomes, irrespective of Ig production. In addition, most mu heavy chain producers had at least one rearranged kappa gene locus. These long-term fetal liver cultures provide large numbers of cells for studying events early in the B lymphocyte lineage. The cultured fetal liver cells retained phenotypic traits similar to fresh fetal liver B cells and distinctive from bone marrow cells cultured under similar conditions.

Transdifferentiation of Bone Marrow-Derived Cells Co-Cultured with Fetal Liver Cells into Hepatic-Like Cells without Fusion.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4176-4176
Author(s):  
Yasuhiro Yamada ◽  
Yuji Yonemura ◽  
Eishi Nishimoto ◽  
Hiroaki Mitsuya
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Cells ◽  
Fetal Liver ◽  
Liver Cells ◽  
Cytokeratin 19 ◽  
Rt Pcr ◽  
Hematopoietic Stem ◽  
Bone Marrow Derived Cells ◽  
Fetal Liver Cells

Abstract Several research groups have reported that bone marrow cells (BMCs) transdifferentiate into hepatocytes in rodents. However, it is yet to be studied what factors effectively trigger and sustain the transdifferentiation of BMCs to hepatocytes. In the present study, we investigated whether murine BMCs in the presence of fetal liver cells (FLCs) could differentiate into hepatic-like cells in vitro without fusion. Fractionated BMCs from C57Bl/6-TgN(ACTbEGFP)10bs mice and FLCs from B6.129S7-Gt(ROSA)26Sor mice were co-cultured at 1x105 cells and 1x106 cells in 10% FCS-containing medium supplemented with hepatocyte growth factor on laminin-coated dishes. Hepatocyte-specific markers among BMCs were detected as assessed by immunocytochemistry for albumin and reverse transcription-polymerase chain reaction (RT-PCR) for alpha-fetoprotein (AFP), albumin, and cytokeratin-19 mRNAs. We also found that Sca-1+ BMCs containing both hematopoietic stem cells and AFP-expressing cells could differentiate into hepatic-like cells and such cells were seen adherent to dish together with FLCs in the early phase of culture. Moreover, the AFP-expressing cells were found in a Sca-1+ cKit- cell fraction, which also differentiated into CD45− GFP+ albumin+ cells and proved to be positive for GFP but negative for LacZ as assessed by RT-PCR and immunocytochemistry. These results suggest that albumin+ cells developed through transdifferentiation from BMCs but not through spontaneous cell fusion between BMCs and FLCs.

scholarly journals Human fetal liver MSCs are more effective than adult bone marrow MSCs for their immunosuppressive, immunomodulatory, and Foxp3+ T reg induction capacity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yi Yu ◽  
Alejandra Vargas Valderrama ◽  
Zhongchao Han ◽  
Georges Uzan ◽  
Sina Naserian ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Immune Responses ◽  
Molecular Mechanisms ◽  
Fetal Liver ◽  
Cytotoxic T Cells ◽  
Cell Contact ◽  
Adult Bone Marrow ◽  
Adult Bone

Abstract Background Mesenchymal stem cells (MSCs) exhibit active abilities to suppress or modulate deleterious immune responses by various molecular mechanisms. These cells are the subject of major translational efforts as cellular therapies for immune-related diseases and transplantations. Plenty of preclinical studies and clinical trials employing MSCs have shown promising safety and efficacy outcomes and also shed light on the modifications in the frequency and function of regulatory T cells (T regs). Nevertheless, the mechanisms underlying these observations are not well known. Direct cell contact, soluble factor production, and turning antigen-presenting cells into tolerogenic phenotypes, have been proposed to be among possible mechanisms by which MSCs produce an immunomodulatory environment for T reg expansion and activity. We and others demonstrated that adult bone marrow (BM)-MSCs suppress adaptive immune responses directly by inhibiting the proliferation of CD4+ helper and CD8+ cytotoxic T cells but also indirectly through the induction of T regs. In parallel, we demonstrated that fetal liver (FL)-MSCs demonstrates much longer-lasting immunomodulatory properties compared to BM-MSCs, by inhibiting directly the proliferation and activation of CD4+ and CD8+ T cells. Therefore, we investigated if FL-MSCs exert their strong immunosuppressive effect also indirectly through induction of T regs. Methods MSCs were obtained from FL and adult BM and characterized according to their surface antigen expression, their multilineage differentiation, and their proliferation potential. Using different in vitro combinations, we performed co-cultures of FL- or BM-MSCs and murine CD3+CD25−T cells to investigate immunosuppressive effects of MSCs on T cells and to quantify their capacity to induce functional T regs. Results We demonstrated that although both types of MSC display similar cell surface phenotypic profile and differentiation capacity, FL-MSCs have significantly higher proliferative capacity and ability to suppress both CD4+ and CD8+ murine T cell proliferation and to modulate them towards less active phenotypes than adult BM-MSCs. Moreover, their substantial suppressive effect was associated with an outstanding increase of functional CD4+CD25+Foxp3+ T regs compared to BM-MSCs. Conclusions These results highlight the immunosuppressive activity of FL-MSCs on T cells and show for the first time that one of the main immunoregulatory mechanisms of FL-MSCs passes through active and functional T reg induction.

scholarly journals Chromatin structure and developmental expression of the human alpha-globin cluster.

1986 ◽  
Vol 6 (4) ◽  
pp. 1108-1116 ◽  
Author(s):  
M Yagi ◽  
R Gelinas ◽  
J T Elder ◽  
M Peretz ◽  
T Papayannopoulou ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Chromatin Structure ◽  
Bone Marrow Cells ◽  
Fetal Liver ◽  
Globin Gene ◽  
Erythroid Cells ◽  
Adult Bone Marrow ◽  
Hypersensitive Sites ◽  
Alpha Globin ◽  
Adult Bone

The human alpha-like globins undergo a switch from the embryonic zeta-chain to the alpha-chain early in human development, at approximately the same time as the beta-like globins switch from the embryonic epsilon-to the fetal gamma-chains. We investigated the chromatin structure of the human alpha-globin gene cluster in fetal and adult erythroid cells. Our results indicate that DNase I-hypersensitive sites exist at the 5' ends of the alpha 1- and alpha 2-globin genes as well as at several other sites in the cluster in all erythroid cells examined. In addition, early and late fetal liver erythroid cells and adult bone marrow cells contain hypersensitive sites at the 5' end of the zeta gene, and in a purified population of 130-day-old fetal erythroid cells, the entire zeta-to alpha-globin region is sensitive to DNase I digestion. The presence of features of active chromatin in the zeta-globin region in fetal liver and adult bone marrow cells led us to investigate the transcription of zeta in these cells. By nuclear runoff transcription studies, we showed that initiated polymerases are present on the zeta-globin gene in these normal erythroid cells. Immunofluorescence with anti-zeta-globin antibodies also showed that late fetal liver cells contain zeta-globin. These findings demonstrate that expression of the embryonic zeta-globin continues at a low level in normal cells beyond the embryonic to fetal globin switch.

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