The Bone Marrow Hematopoietic Microenvironment Is Functionally Impaired in Iron-Overloaded Mice,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3173-3173
Author(s):  
Hiroshi Okabe ◽  
Takahiro Suzuki ◽  
Eisuke Uehara ◽  
Masuzu Ueda ◽  
Tadashi Nagai ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Bone Marrow ◽  
Iron Overload ◽  
Bone Marrow Cells ◽  
Hematopoietic Cells ◽  
Excess Iron ◽  
Hematopoietic Microenvironment ◽  
Hematopoietic Reconstitution ◽  
Donor Cells ◽  
Marrow Cells

Abstract Abstract 3173 Background and Purpose: Deferasirox (DFX) is an oral iron chelator that enables effective chelation by once daily administration.Since the introduction of DFX, iron chelation therapy (ICT) for transfusional iron overload has attracted increased attention. It is known that excess iron increases oxidative stress and affects various organs, such as the liver, heart and endocrine glands, negatively. Sufficient ICT can remove excess iron and improve organ dysfunction in iron-overloaded patients, and accumulating data has indicated that efficient ICT improves the survival of transfusion-dependent patients with myelodysplastic syndromes (MDS). Recently, we experienced a case of MDS with transfusional iron overload in which the hematopoietic data improved unexpectedly after administration of DFX without any other specific treatments (Okabe H et al. Rinsho Ketsueki, 2009). An increasing number of similar cases has been reported. This clinical observation indicates that iron overload could also affect the hematopoietic system unfavorably, via, as yet, unknown mechanisms. Methods and Results: We generated iron-overloaded mice to investigate how iron overload affects hematopoiesis in vivo. C57BL6 mice were injected with a total of 200 mg of iron dextran, intraperitoneally over 4 weeks. The iron-overloaded mice showed pigmented skin and hepatosplenomegaly, and histological examination showed excess iron deposition in the bone marrow, liver, spleen and heart. The serum and organ iron concentrations in these mice markedly increased. However, the iron-overloaded mice did not show any significant changes in peripheral blood counts or the proportion of immature hematopoietic cells in the bone marrow. To further examine the effects of excess iron on the biological functions of hematopoietic stem and progenitor cells (HSPCs), we performed bone marrow transplantation (BMT) assays. First, to assess the hematopoietic reconstitutional capacity of the HSPCs of iron-overloaded mice, we transplanted bone marrow cells (1×106 cells) from iron-overloaded mice or normal mice into lethally irradiated normal recipient mice along with the same number of normal competitor cells. We found no significant difference in hematopoietic reconstitution between the iron-overloaded donor cells and the normal donor cells, suggesting that the hematopoietic reconstitutional capacity of HSPCs in iron-overloaded mice is not significantly affected by iron. In contrast, when we transplanted bone marrow cells from normal mice (2×106 cells) into iron-overloaded recipients, hematopoietic recovery was significantly delayed, in particular platelet counts (at 2 weeks after BMT, normal recipients vs. iron-overloaded recipients, 63.4±9.4 vs. 18.7±4.7×104/μl, respectively, p<0.001). This indicates that excess iron disturbs the function of the bone marrow microenvironment and delays hematopoietic reconstitution. Microarray and quantitative RT-PCR analysis of non-hematopoietic bone marrow cells (CD45-/Ter119-) from the iron-overloaded mice demonstrated significant reductions in CXCL12, VCAM-1, Kit-ligand and IGF-1, which are important regulators of hematopoiesis. In addition, in the iron-overloaded mice, the serum concentration of erythropoietin and the expression level of thrombopoietin in the liver were also significantly reduced. Furthermore, increased oxidative stress levels were observed in the iron-overloaded liver and bone marrow. Conclusion: We did not observe any direct effects of excessive iron on hematopoietic cells, but found significant impairment of the hematopoietic microenvironment in the bone marrow of iron-overloaded mice. These results suggest that oxidative stress induced by excess iron could disturb the hematopoiesis-supporting capacity of the bone marrow microenvironment by reducing the expression of many essential molecules. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Antioxidant Fusion Protein SOD1-Tat Increases the Engraftment Efficiency of Total Bone Marrow Cells in Irradiated Mice

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3395
Author(s):  
Ting Bei ◽  
Xusong Cao ◽  
Yun Liu ◽  
Jinmei Li ◽  
Haihua Luo ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Fusion Protein ◽  
Bone Marrow Cells ◽  
Standard Procedure ◽  
Severe Infection ◽  
Copper Zinc Superoxide Dismutase ◽  
Donor Cells ◽  
Total Bone Marrow ◽  
Marrow Cells

Total body irradiation is a standard procedure of bone marrow transplantation (BMT) which causes a rapid increase in reactive oxygen species (ROS) in the bone marrow microenvironment during BMT. The increase in ROS reduces the engraftment ability of donor cells, thereby affecting the bone marrow recovery of recipients after BMT. In the early weeks following transplantation, recipients are at high risk of severe infection due to weakened hematopoiesis. Thus, it is imperative to improve engraftment capacity and accelerate bone marrow recovery in BMT recipients. In this study, we constructed recombinant copper/zinc superoxide dismutase 1 (SOD1) fused with the cell-penetrating peptide (CPP), the trans-activator of transcription (Tat), and showed that this fusion protein has penetrating ability and antioxidant activity in both RAW264.7 cells and bone marrow cells in vitro. Furthermore, irradiated mice transplanted with SOD1-Tat-treated total bone marrow donor cells showed an increase in total bone marrow engraftment capacity two weeks after transplantation. This study explored an innovative method for enhancing engraftment efficiency and highlights the potential of CPP-SOD1 in ROS manipulation during BMT.

scholarly journals Cytokine-Facilitated Transduction Leads to Low-Level Engraftment in Nonablated Hosts

Blood ◽  
1997 ◽  
Vol 90 (2) ◽  
pp. 865-872 ◽  
Author(s):  
Ellen L.W. Kittler ◽  
Stefan O. Peters ◽  
Rowena B. Crittenden ◽  
Michelle E. Debatis ◽  
Hayley S. Ramshaw ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Polymerase Chain Reaction ◽  
Bone Marrow Cells ◽  
Mdr1 Gene ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Donor Cells ◽  
Polymerase Chain ◽  
Marrow Cells

Using a murine bone marrow transplantation model, we evaluated the long-term engraftment of retrovirally transduced bone marrow cells in nonmyeloablated hosts. Male bone marrow was stimulated in a cocktail of interleukin-3 (IL-3), IL-6, IL-11, and stem cell factor (SCF ) for 48 hours, then cocultured on the retroviral producer line MDR18.1 for an additional 24 hours. Functional transduction of hematopoietic progenitors was detected in vitro by reverse transcriptase-polymerase chain reaction (RT-PCR) amplification of multiple drug resistance 1 (MDR1) mRNA from high proliferative potential-colony forming cell (HPP-CFC) colonies. After retroviral transduction, male bone marrow cells were injected into nonablated female mice. Transplant recipients received three TAXOL (Bristol-Myers, Princeton, NJ) injections (10 mg/kg) over a 14-month period. Transplant recipient tissues were analyzed by Southern blot and fluorescence in situ hybridization for Y-chromosome–specific sequences and showed donor cell engraftment of approximately 9%. However, polymerase chain reaction amplification of DNAs from bone marrow, spleen, and peripheral blood showed no evidence of the transduced MDR1 gene. RT-PCR analysis of total bone marrow RNA showed that transcripts from the MDR1 gene were present in a fraction of the engrafted donor cells. These data show functional transfer of the MDR1 gene into nonmyeloablated murine hosts. However, the high rates of in vitro transduction into HPP-CFC, coupled with the low in vivo engraftment rate of donor cells containing the MDR1 gene, suggest that the majority of stem cells that incorporated the retroviral construct did not stably engraft in the host. Based on additional studies that indicate that ex vivo culture of bone marrow induces an engraftment defect concomitantly with progression of cells through S phase, we propose that the cell cycle transit required for proviral integration reduces or impairs the ability of transduced cells to stably engraft.

scholarly journals Friend Leukemia Virus Infection Enhances DNA Damage-Induced Apoptosis of Hematopoietic Cells, Causing Lethal Anemia in C3H Hosts

2002 ◽  
Vol 76 (15) ◽  
pp. 7790-7798 ◽  
Author(s):  
Masanobu Kitagawa ◽  
Shuichi Yamaguchi ◽  
Maki Hasegawa ◽  
Kaoru Tanaka ◽  
Toshihiko Sado ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Dna Damage ◽  
Knockout Mice ◽  
Bone Marrow Cells ◽  
Leukemia Virus ◽  
Hematopoietic Cells ◽  
Friend Leukemia ◽  
C3h Mice ◽  
Friend Leukemia Virus ◽  
Marrow Cells

ABSTRACT Exposure of hematopoietic progenitors to gamma irradiation induces p53-dependent apoptosis. However, host responses to DNA damage are not uniform and can be modified by various factors. Here, we report that a split low-dose total-body irradiation (TBI) (1.5 Gy twice) to the host causes prominent apoptosis in bone marrow cells of Friend leukemia virus (FLV)-infected C3H mice but not in those of FLV-infected DBA mice. In C3H mice, the apoptosis occurs rapidly and progressively in erythroid cells, leading to lethal host anemia, although treatment with FLV alone or TBI alone induced minimal apoptosis in bone marrow cells. A marked accumulation of P53 protein was demonstrated in bone marrow cells from FLV-infected C3H mice 12 h after treatment with TBI. Although a similar accumulation of P53 was also observed in bone marrow cells from FLV-infected DBA mice treated with TBI, the amount appeared to be parallel to that of mice treated with TBI alone and was much lower than that of FLV- plus TBI-treated C3H mice. To determine the association of p53 with the prominent enhancement of apoptosis in FLV- plus TBI-treated C3H mice, p53 knockout mice of the C3H background (C3H p53−/− ) were infected with FLV and treated with TBI. As expected, p53 knockout mice exhibited a very low frequency of apoptosis in the bone marrow after treatment with FLV plus TBI. Further, C3H p53−/− → C3H p53+/+ bone marrow chimeric mice treated with FLV plus TBI survived even longer than the chimeras treated with FLV alone. These findings indicate that infection with FLV strongly enhances radiation-induced apoptotic cell death of hematopoietic cells in host animals and that the apoptosis occurs through a p53-associated signaling pathway, although the response was not uniform in different host strains.

scholarly journals Augmented Production of Interleukin-6 by Normal Human Osteoblasts in Response to CD34+ Hematopoietic Bone Marrow Cells In Vitro

Blood ◽  
1997 ◽  
Vol 89 (4) ◽  
pp. 1165-1172 ◽  
Author(s):  
Russell S. Taichman ◽  
Marcelle J. Reilly ◽  
Rama S. Verma ◽  
Stephen G. Emerson
Keyword(s):  
Bone Marrow ◽  
Interleukin 6 ◽  
Transforming Growth Factor ◽  
Bone Marrow Cells ◽  
Hematopoietic Cells ◽  
Cell Types ◽  
Colony Stimulating Factor ◽  
Cd34 Cells ◽  
Stimulating Factor ◽  
Marrow Cells

Abstract Based on anatomic and developmental findings characterizing hematopoietic cells in close approximation with endosteal cells, we have begun an analysis of osteoblast/hematopoietic cell interactions. We explore here the functional interdependence between these two cell types from the standpoint of de novo cytokine secretion. We determined that, over a 96-hour period, CD34+ bone marrow cells had no significant effect on osteoblast secretion of granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, or transforming growth factor-β1 , but in some experiments minor increases in leukemia inhibitory factor levels were observed. However, when CD34+ bone marrow cells were cocultured in direct contact with osteoblasts, a 222% ± 55% (range, 153% to 288%) augmentation in interleukin-6 (IL-6) synthesis was observed. The accumulation of IL-6 protein was most rapid during the initial 24-hour period, accounting for nearly 55% of the total IL-6 produced by osteoblasts in the absence of blood cells and 77% of the total in the presence of the CD34+ cells. Cell-to-cell contact does not appear to be required for this activity, as determined by coculturing the two cell types separated by porous micromembranes. The identity of the soluble activity produced by the CD34+ cells remains unknown, but is not likely due to IL-1β or tumor necrosis factor-α, as determined with neutralizing antibodies. To our knowledge, these data represent the first demonstration that early hematopoietic cells induce the production of molecules required for the function of normal bone marrow microenvironments, in this case through the induction of hematopoietic cytokine (IL-6) secretion by osteoblasts.

scholarly journals Cytokine-Facilitated Transduction Leads to Low-Level Engraftment in Nonablated Hosts

Blood ◽  
1997 ◽  
Vol 90 (2) ◽  
pp. 865-872 ◽  
Author(s):  
Ellen L.W. Kittler ◽  
Stefan O. Peters ◽  
Rowena B. Crittenden ◽  
Michelle E. Debatis ◽  
Hayley S. Ramshaw ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Polymerase Chain Reaction ◽  
Bone Marrow Cells ◽  
Mdr1 Gene ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Donor Cells ◽  
Polymerase Chain ◽  
Marrow Cells

Abstract Using a murine bone marrow transplantation model, we evaluated the long-term engraftment of retrovirally transduced bone marrow cells in nonmyeloablated hosts. Male bone marrow was stimulated in a cocktail of interleukin-3 (IL-3), IL-6, IL-11, and stem cell factor (SCF ) for 48 hours, then cocultured on the retroviral producer line MDR18.1 for an additional 24 hours. Functional transduction of hematopoietic progenitors was detected in vitro by reverse transcriptase-polymerase chain reaction (RT-PCR) amplification of multiple drug resistance 1 (MDR1) mRNA from high proliferative potential-colony forming cell (HPP-CFC) colonies. After retroviral transduction, male bone marrow cells were injected into nonablated female mice. Transplant recipients received three TAXOL (Bristol-Myers, Princeton, NJ) injections (10 mg/kg) over a 14-month period. Transplant recipient tissues were analyzed by Southern blot and fluorescence in situ hybridization for Y-chromosome–specific sequences and showed donor cell engraftment of approximately 9%. However, polymerase chain reaction amplification of DNAs from bone marrow, spleen, and peripheral blood showed no evidence of the transduced MDR1 gene. RT-PCR analysis of total bone marrow RNA showed that transcripts from the MDR1 gene were present in a fraction of the engrafted donor cells. These data show functional transfer of the MDR1 gene into nonmyeloablated murine hosts. However, the high rates of in vitro transduction into HPP-CFC, coupled with the low in vivo engraftment rate of donor cells containing the MDR1 gene, suggest that the majority of stem cells that incorporated the retroviral construct did not stably engraft in the host. Based on additional studies that indicate that ex vivo culture of bone marrow induces an engraftment defect concomitantly with progression of cells through S phase, we propose that the cell cycle transit required for proviral integration reduces or impairs the ability of transduced cells to stably engraft.

Enforced Expression of the GATA-2 Transcription Factor Blocks Normal Hematopoiesis

Blood ◽  
1999 ◽  
Vol 93 (2) ◽  
pp. 488-499 ◽  
Author(s):  
Derek A. Persons ◽  
James A. Allay ◽  
Esther R. Allay ◽  
Richard A. Ashmun ◽  
Donald Orlic ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Transcription Factor ◽  
Blood Cell ◽  
Fluorescent Protein ◽  
Bone Marrow Cells ◽  
Hematopoietic Cells ◽  
Immunoblot Analysis ◽  
Marrow Cells

Abstract The zinc finger transcription factor GATA-2 is highly expressed in immature hematopoietic cells and declines with blood cell maturation. To investigate its role in normal adult hematopoiesis, a bicistronic retroviral vector encoding GATA-2 and the green fluorescent protein (GFP) was used to maintain the high levels of GATA-2 that are normally present in primitive hematopoietic cells. Coexpression of the GFP marker facilitated identification and quantitation of vector-expressing cells. Bone marrow cells transduced with the GATA-2 vector expressed GFP as judged by flow cytometry and GATA-2 as assessed by immunoblot analysis. A 50% to 80% reduction in hematopoietic progenitor-derived colony formation was observed with GATA-2/GFP-transduced marrow, compared with marrow transduced with a GFP-containing vector lacking the GATA-2 cDNA. Culture of purified populations of GATA-2/GFP-expressing and nonexpressing cells confirmed a specific ablation of the colony-forming ability of GATA-2/GFP-expressing progenitor cells. Similarly, loss of spleen colony-forming ability was observed for GATA-2/GFP-expressing bone marrow cells. Despite enforced GATA-2 expression, marrow cells remained viable and were negative in assays to evaluate apoptosis. Although efficient transduction of primitive Sca-1+Lin- cells was observed with the GATA-2/GFP vector, GATA-2/GFP-expressing stem cells failed to substantially contribute to the multilineage hematopoietic reconstitution of transplanted mice. Additionally, mice transplanted with purified, GATA-2/GFP-expressing cells showed post-transplant cytopenias and decreased numbers of total and gene-modified bone marrow Sca-1+ Lin−cells. Although Sca-1+ Lin− bone marrow cells expressing the GATA-2/GFP vector were detected after transplantation, no appreciable expansion in their numbers occurred. In contrast, control GFP-expressing Sca-1+Lin− cells expanded at least 40-fold after transplantation. Thus, enforced expression of GATA-2 in pluripotent hematopoietic cells blocked both their amplification and differentiation. There appears to be a critical dose-dependent effect of GATA-2 on blood cell differentiation in that downregulation of GATA-2 expression is necessary for stem cells to contribute to hematopoiesis in vivo.

Stathmin 1 Is Involved In The Highly Proliferative Phenotype Of High-Risk Myelodysplastic Syndromes and Acute Leukemia Cells

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 861-861
Author(s):  
João Agostinho Machado-Neto ◽  
Paula de Melo Campos ◽  
Patricia Favaro ◽  
Mariana Lazarini ◽  
Irene Lorand-Metze ◽  
...  
Keyword(s):  
Bone Marrow ◽  
High Risk ◽  
Bone Marrow Cells ◽  
Hematopoietic Cells ◽  
Leukemia Cell ◽  
Low Risk ◽  
Leukemia Cells ◽  
Healthy Donors ◽  
Stathmin 1 ◽  
Marrow Cells

Abstract Introduction : Stathmin 1, also known as Oncoprotein 18 (OP18) or Leukemia-associated phosphoprotein p18 (LAP18), is an important cytoplasmic microtubule-destabilizing protein that plays a critical role in the process of mitosis, proliferation and accurate chromosome segregation through regulation of microtubule dynamics. High levels of Stathmin 1 have been reported in solid tumors and have been associated with poor prognosis in various types of cancers. The identification of overactive proteins in leukemia cells, compared to normal hematopoietic cells, as well as understanding the molecular and cellular basis of the disease may provide new therapeutic opportunities. Aims: To evaluate Stathmin 1 expression in proliferating and non-proliferating hematopoietic cells, in bone marrow cells from healthy donors and from patients with myelodysplastic syndromes (MDS), acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL). In addition, we evaluated the effect of Stathmin 1 silencing on proliferation and apoptosis in the U937 acute myeloid leukemia cell line. Materials and Methods: A panel of human leukemia cell lines that included myeloid (K562, KU812, NB4, HL60, P39, HEL, U937, KG1 and THP1) and lymphoid cells (Jurkat, MOLT4, Daudi, Raji, Namalwa and Karpas 422) in exponential growth was used. Peripheral blood lymphocytes (PBL) were induced, or not, to proliferate upon PHA stimulation for 72 hours. A total of 30 healthy donors and 117 patients at diagnosis (MDS=52 [low-risk=36, high-risk=16], AML=49, and ALL=16) were included in the study. Stathmin 1 gene and protein expression was evaluated by qPCR and Western blot. Stathmin 1 was stably knocked down with specific shRNA-expressing lentiviral vector and cell growth was examined by MTT assay, clonogenicity by colony formation and apoptosis by AnnexinV/PI. Appropriate statistical analyses were performed; results are expressed as median (minimum- maximum). Results: A higher expression of Stathmin 1 was observed in all leukemia cell lines, when compared with normal non-proliferating hematopoietic cells. We also observed a marked increase in Stathmin 1 expression in PBL induced to proliferate with PHA after 72 hours. Stathmin 1 transcripts were significantly increased in total bone marrow cells from patients with AML (2.01 [0.35-8.88]; p=.0009) and ALL (2.94 [1.16-10.82]; p=.0004), compared with healthy donors (1.01 [0.38-4.08]). No difference in Stathmin 1 expression was observed between healthy donors and MDS patients. When the MDS group was stratified by the WHO classification into low and high-risk MDS, Stathmin 1 expression was significantly higher in the high-risk, when compared with low-risk MDS (1.62 [0.42–3.28] vs. 1.13 [0.36–2.61], p=.03). Similar results were found in isolated CD34+ bone marrow cells, Stathmin 1 transcripts were significantly increased in CD34+ AML cells compared with CD34+ normal cells, and in high-risk compared with low-risk MDS (all p≤.02). Interestingly, 3 out of 5 MDS patients showed a significant increase in Stathmin 1 transcripts after disease progression. Also, a significant positive correlation was observed between percentage of bone marrow blasts and Stathmin 1 expression in MDS patients (p=.03; r=.31). In U937 leukemia cells, Stathmin 1 silencing significantly reduced cell proliferation (p=.02) and clonal growth (p<.0001), but did not modulate apoptosis. Conclusions: Stathmin 1 is overexpressed in high-risk MDS and acute leukemia cells, and is upregulated during MDS progression, suggesting that Stathmin 1 plays a role in the highly proliferative phenotype. Our study adds new insights to the role of Stathmin 1 in leukemogenesis. Future studies are necessary to validate whether Stathmin 1 is a predictive marker for MDS progression, and to determinate whether Stathmin 1 is a “driver” or a “passenger” during malignant transformation. Disclosures: No relevant conflicts of interest to declare.

Impaired Granulocytic Differentiation In Vitro in Hematopoietic Cells Lacking Retinoic Acid Receptors α1 and γ

Blood ◽  
1998 ◽  
Vol 92 (2) ◽  
pp. 607-615 ◽  
Author(s):  
Jean Labrecque ◽  
Deborah Allan ◽  
Pierre Chambon ◽  
Norman N. Iscove ◽  
David Lohnes ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Retinoic Acid ◽  
Bone Marrow Cells ◽  
Hematopoietic Cells ◽  
Hematopoietic Cell ◽  
Retinoic Acid Receptors ◽  
Wild Type ◽  
Granulocytic Differentiation ◽  
Marrow Cells

Transcripts for the retinoic acid receptors (RARs) α1, α2, γ1, and γ2 were found in the granulocytic lineage (Gr-1+cells) through semiquantitative polymerase chain reaction (PCR) analysis. The screening of single cell cDNA libraries derived from hematopoietic progenitors also showed the presence of RARα and, to a lesser extent, RARγ transcripts in committed granulocyte (colony-forming unit-granulocyte [CFU-G]) or granulocyte-macrophage (CFU-GM) colony-forming cells. The contribution of RARα1 and γ to hematopoietic cell differentiation was therefore investigated in mice bearing targeted disruption of either one or both of these loci. Because RARγ and RARα1γ compound null mutants die shortly after birth, bone marrow cells were collected from fetuses at 18.5 days postcoitum (dpc) and evaluated for growth and differentiation in culture in the presence of Steel factor (SF), interleukin-3 (IL-3), and erythropoietin (Epo). The frequency of colony-forming cells from bone marrow populations derived from RARα1/γ double null mice was not significantly different from that of RARγ or RARα1 single nulls or from wild-type controls. In addition, the distribution of erythroid, granulocyte, and macrophage colonies was comparable between hematopoietic cells from all groups, suggesting that lineage commitment was not affected by the lack of RARα1 and/or RARγ. Colony cells were then harvested individually and evaluated by morphologic criteria. While terminal granulocyte differentiation was evident in wild-type cells and colonies from either single null mutant, colonies derived from RARα1−/−γ−/− bone marrow populations were blocked at the myelocyte and, to a lesser extent, at the metamyelocyte stages, whereas erythroid and macrophage differentiation was not affected. Together, these results indicate that both RARα1 and γ are required for terminal maturation in the granulocytic lineage in vitro, but appear to be dispensable for the early stages of hematopoietic cell development. Our results raise the possibility that in acute promyelocytic leukemia (APL), the different RARα fusion proteins cause differentiation arrest at a stage when further maturation requires not only RARα, but also RARγ. Finally, bone marrow cells appear to differentiate normally in vivo, suggesting an effective compensation mechanism in the RARα1/γ double null mice.

Pathways in the development of liver macrophages: alternative precursors contained in populations of lymphocytes and bone-marrow cells

1968 ◽  
Vol 169 (1016) ◽  
pp. 307-327 ◽  
Keyword(s):  
Bone Marrow ◽  
Thoracic Duct ◽  
Bone Marrow Cells ◽  
Marker Chromosome ◽  
Proliferating Cells ◽  
Liver Macrophages ◽  
Bone Marrow Precursor ◽  
Liver Macrophage ◽  
Donor Cells ◽  
Marrow Cells

The origin of dividing liver macrophages during states of intense reticulo-endothelial stimulation has been studied in mice by means of the T 6 marker chromosome. The cells were isolated for cytological analysis by means of Garvey’s technique of collagenase and trypsin digestion. During the proliferative phase of graft-versus-host ( GVH ) reaction in the strain combination C 57BL → (C57BL x CBA-T6T6)F 1 , practically all liver macrophages in mitosis were of donor karyotype, even when relatively pure suspensions of thoracic duct small lymphocytes were used as the donor cells. Several lines of evidence established that the dividing cells analysed were part of a macrophage response. The isolated cells in mitosis had macrophage characteristics which reflected the cell proliferation examined in histological sections. This proliferation was largely restricted to the liver sinusoids and to cells with phagocytic properties. The same proportion of these cells appeared to be actively phagoctyic before their arrest in metaphase by Colcemid during GVH reaction as was found in normal mice. Furthermore, more than 70% of the liver sinusoidal cells which incorporated 3 H -thymidine were demonstrably phagocytic before and/or after labelling. Liver macrophage proliferation was greatly depressed by splenectomy 24 h after injection of donor cells, although cells of donor karyotype were still predominant. Similar techniques have been applied to syngeneic radiation chimaeras—( CBA x CBA-T6T6 ) F 1 mice ‘repopulated’ with CBA- T6T6 lymphocytes and CBA bone marrow. When Corynebacterium parvum vaccine was applied as a stimulant, two-thirds of dividing liver macrophages were found to be of lymphocyte origin and one-third or less derived from a precursor in bone marrow cells. Using partial hepatectomy to stimulate macrophage proliferation in these chimaeras, however, it was found that the overwhelming majority were derived from the bone-marrow precursor. The phagocytic property of the majority of proliferating cells was established by combined colloid and 3 H-thymidine labelling. It is concluded that liver macrophages derived from either of two different precursors in populations of recirculating lymphocytes and bone marrow cells respectively can proliferate preferentially, according to the nature of the reticulo-endothelial stimulus. Evidence from a variety of sources supports the contention that the bone-marrow precursor cell represents the major source of ‘normal’ macrophages. Whether the precursor amongst thoracic duct cells is identifiable with any previously recognized category of lymphocyte is not yet known. Its utilization has only been detected so far during conditions of intense reticulo-endothelial stimulation.

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