scholarly journals Retrovirus-induced feline pure red blood cell aplasia: pathogenesis and response to suramin

Blood ◽  
1991 ◽  
Vol 77 (7) ◽  
pp. 1442-1451
Author(s):  
JL Abkowitz
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Mononuclear Cells ◽  
Leukemia Virus ◽  
Transcriptase Inhibitor ◽  
Feline Leukemia Virus ◽  
Erythroid Progenitors ◽  
Marrow Cultures

Feline leukemia virus, subgroup C/Sarma (FeLV-C/Sarma) induces pure red blood cell aplasia in cats. Although erythroid (BFU-E and CFU-E) and granulocyte/macrophage (CFU-GM) progenitors are infected with this virus, only erythropoiesis is impaired. Two to 3 weeks before the onset of anemia, CFU-E become undetectable in marrow cultures while earlier erythroid progenitors (BFU-E) persist, suggesting that FeLV-C/Sarma (presumably via its envelope glycoprotein gp70) inhibits the differentiation of BFU-E to CFU-E in vivo. To correlate in vitro observations with the progression of disease, prospective studies were performed in six cats. These studies showed that at the time that the frequencies of CFU-E decreased in marrow cultures, BFU-E no longer responded to hematopoietic growth factor(s), although the responses of CFU-GM were unchanged. In further studies, anemic cats received suramin, a reverse-transcriptase inhibitor with other diverse effects. Within 4 to 14 days, erythropoiesis improved and up to 1,616 CFU-E were detected per 10(5) marrow mononuclear cells. However, progenitor cells remained infected, suggesting that suramin modulated erythroid differentiation without inhibiting progenitor infection. These observations led to the hypothesis that the gp70 of FeLV-C/Sarma impairs BFU-E differentiation by interference with ligand/receptor interactions or signal transduction pathways unique to erythroid cells. Understanding this mechanism should provide insights into the interactions controlling early erythropoiesis.

scholarly journals Retrovirus-induced feline pure red blood cell aplasia: pathogenesis and response to suramin

Blood ◽  
1991 ◽  
Vol 77 (7) ◽  
pp. 1442-1451 ◽  
Author(s):  
JL Abkowitz
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Mononuclear Cells ◽  
Leukemia Virus ◽  
Transcriptase Inhibitor ◽  
Feline Leukemia Virus ◽  
Erythroid Progenitors ◽  
Marrow Cultures

Abstract Feline leukemia virus, subgroup C/Sarma (FeLV-C/Sarma) induces pure red blood cell aplasia in cats. Although erythroid (BFU-E and CFU-E) and granulocyte/macrophage (CFU-GM) progenitors are infected with this virus, only erythropoiesis is impaired. Two to 3 weeks before the onset of anemia, CFU-E become undetectable in marrow cultures while earlier erythroid progenitors (BFU-E) persist, suggesting that FeLV-C/Sarma (presumably via its envelope glycoprotein gp70) inhibits the differentiation of BFU-E to CFU-E in vivo. To correlate in vitro observations with the progression of disease, prospective studies were performed in six cats. These studies showed that at the time that the frequencies of CFU-E decreased in marrow cultures, BFU-E no longer responded to hematopoietic growth factor(s), although the responses of CFU-GM were unchanged. In further studies, anemic cats received suramin, a reverse-transcriptase inhibitor with other diverse effects. Within 4 to 14 days, erythropoiesis improved and up to 1,616 CFU-E were detected per 10(5) marrow mononuclear cells. However, progenitor cells remained infected, suggesting that suramin modulated erythroid differentiation without inhibiting progenitor infection. These observations led to the hypothesis that the gp70 of FeLV-C/Sarma impairs BFU-E differentiation by interference with ligand/receptor interactions or signal transduction pathways unique to erythroid cells. Understanding this mechanism should provide insights into the interactions controlling early erythropoiesis.

FLVCRb: a Mitochondrial FLVCR Isoform Important for Erythropoiesis

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4243-4243
Author(s):  
Deborah Chiabrando ◽  
Sonia Mercurio ◽  
Samuele Marro ◽  
Sharmila Fagoonee ◽  
Erika Messana ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Mouse Model ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Leukemia Virus ◽  
Feline Leukemia Virus ◽  
Knock Out ◽  
Skeletal Malformations ◽  
Fetal Erythropoiesis

Abstract Abstract 4243 Feline Leukemia Virus subgroup C Receptor (FLVCR) was originally identified and cloned as a cell-surface protein receptor for feline leukemia virus subgroup C, causing pure red blood cell aplasia in cats. Recent studies have demonstrated that FLVCR is a heme exporter which is essential for erythropoiesis. The heme efflux via FLVCR was shown to be essential for erythroid differentiation in K562 cells as well as in CD34+ precursors cells1. Moreover, Keel and co-authors have reported that Flvcr-null mice die in utero due to the failure of fetal erythropoiesis; also post-natal mice lacking FLVCR showed severe anemia. In addition to the erythroid defect, Flvcr-null embryos display defective growth and developmental anomalies2. We have identified an alternative transcription start site giving rise to a novel FLVCR isoform (FLVCRb). Flvcr-b transcript completely lacks the first exon of the canonical isoform (FLVCRa) and code for a putative 6 transmembrane domain containing protein ubiquitously expressed. In vitro over-expression of FLVCRa and FLVCRb showed that the two proteins display different subcellular localization. As expected, FLVCRa is localized at the cell membrane while FLVCRb is in the mitochondrial compartment. The mitochondrial localization of this novel isoform is further confirmed by the identification of a N-terminal mitochondrial sorting presequence. The mitochondrion is the site in which heme biosynthesis occurs. Although all the enzymatic reactions involved in heme synthesis are well characterized, how heme is exported to the cytosol is largely unknown. Because of FLVCRa is a heme exporter at the cell membrane, we hypothesized that FLVCRb could be the mitochondrial heme exporter. According to this hypothesis, FLVCRb expression increased following the stimulation of heme biosynthesis in vitro, in correlation with the increase in hemoglobin production. The ability of FLVCRb to bind and export heme out of the mitochondria is still under investigation. To gain insights into the specific roles of the two isoforms, we have generated Flvcr mutant mice different from those previously reported2. Keel and co-author generated a mouse model in which both FLVCRa and FLVCRb have been deleted. In our mouse model, FLVCRa has been specifically deleted while FLVCRb is still expressed (FLVCRa-null mice). Flvcr-a +/− mice were grossly normal, fertile and indistinguishable from their wild-type littermates. When Flvcr-a +/− mice were intercrossed, no Flvcr-a homozygous knock-out newborns were obtained. The analysis of the embryos from timed Flvcr-a +/− intercrosses showed that the Flvcr-a homozygous knock-out genotype was lethal between E14.5 and the birth. E13.5 Flvcr-a-null embryos showed multifocal and extended hemorrhages, visible in the limbs, head and throughout the body wall, as well as subcutaneous edema. Imcomplete vasculogenesis in the Flvcr-a-null embryos was observed at E11.5, a developmental stage in which hemorrhages were not still evident. This suggests that hemorrhages arise from a defect in the development of embryonic vasculature. Moreover, FLVCRa-null embryos showed skeletal abnormalities as demonstrated by Alcian blue-alizarin red staining. Skeletal malformations were evident in the limb where digits did not form properly and in the head where Meckel's cartilage was incomplete. It is interesting to note that this kind of malformations also occurs in Diamond Blackfan Anemia (DBA) patients. Surprisingly, flow cytometric analyses of E14.5 fetal liver cells double-stained for Ter119 (erythroid-specific antigen) and CD71 (transferrin receptor) showed normal erythropoiesis in Flvcr-a-null embryos, in opposition to what occurs in the previously reported Flvcr-null mice2. Taken together, these data demonstrated that FLVCRb is sufficient to support fetal erythropoiesis when the expression of FLVCRa is loss, likely exporting heme out of the mithocondrion for hemoglobin synthesis. Moreover, the loss of FLVCRa leads to incomplete vasculogenesis, hemorrhages and skeletal malformations highlighting new roles of FLVCRa in these processes. 1. Quigley JG et al. Identification of a human heme exporter that is essential for erythropoiesis. Cell 2004 2. Keel SB et al. A heme export protein is required for red blood cell differentiation and iron homeostasis. Science 2008. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Studies in feline long-term marrow culture: hematopoiesis on normal and feline leukemia virus infected stromal cells

Blood ◽  
1992 ◽  
Vol 80 (3) ◽  
pp. 651-662
Author(s):  
ML Linenberger ◽  
JL Abkowitz
Keyword(s):  
Stromal Cells ◽  
Mononuclear Cells ◽  
Clonal Selection ◽  
Leukemia Virus ◽  
Feline Leukemia Virus ◽  
Erythroid Progenitors ◽  
Gag Protein ◽  
Cell Engraftment

To study the effects of feline leukemia virus (FeLV) on the hematopoietic microenvironment, a two-step feline long-term marrow culture (LTMC) system was developed and characterized. The adherent, stromal layer of these cultures is composed of fibroblastoid cells (50% to 80%), macrophages (10% to 30%), fat cells (10% to 20%), and large, polygonal cells that express muscle actin (1% to 2%). When fresh, enriched marrow mononuclear cells (MMNC) were added to 3-week-old irradiated stromal cultures, nonadherent erythroid progenitors (BFU-E) and granulocyte/macrophage progenitors (CFU-GM) could be detected for up to 5 and 12 weeks, respectively. LTMC stromal layers established from marrow cells from cats viremic with either a nonpathogenic strain of FeLV (FeLV-A/61E) or the anemogenic strain FeLV-C/Sarma were morphologically equivalent to uninfected LTMC stromal layers, although more than 80% of the stromal cells expressed FeLV gag protein. When FeLV-infected stromal cultures were recharged with uninfected MMNC, altered patterns of hematopoiesis were observed, compared with recharged, uninfected stromal cultures. In cultures with infected stroma, fewer nonadherent cells (NAC), nonadherent BFU-E, and nonadherent CFU-GM were detected during the first 4 to 5 weeks after recharge. In contrast, greater numbers of NAC and nonadherent CFU-GM were found from weeks 5 to 12 after recharge. When FeLV-infected stromal cultures were recharged with MMNC from a cat heterozygous for the X-chromosome-linked enzyme glucose-6-phosphate dehydrogenase (G-6- PD), the percentage of nonadherent CFU-GM expressing the domestic type G-6-PD isoenzyme remained stable over time (mean % domestic [%d], 53% +/- 3%), and was equivalent to that of nonadherent CFU-GM maintained in uninfected cultures (mean %d, 56% +/- 3%), indicating that clonal drift or clonal selection was not responsible for the enhanced maintenance of CFU-GM. Furthermore, as only 10% to 20% of recharged hematopoietic cells became infected with FeLV in vitro, it is unlikely that the altered pattern was due to progenitor infection. We hypothesize that the increase in NAC and nonadherent CFU-GM in FeLV-infected cultures resulted from enhanced growth factor production by stromal cells. The two-step LTMC system may facilitate the characterization of stromal- derived factors that affect progenitor cell engraftment and proliferation.

scholarly journals Studies in feline long-term marrow culture: hematopoiesis on normal and feline leukemia virus infected stromal cells

Blood ◽  
1992 ◽  
Vol 80 (3) ◽  
pp. 651-662 ◽  
Author(s):  
ML Linenberger ◽  
JL Abkowitz
Keyword(s):  
Stromal Cells ◽  
Mononuclear Cells ◽  
Clonal Selection ◽  
Leukemia Virus ◽  
Feline Leukemia Virus ◽  
Erythroid Progenitors ◽  
Gag Protein ◽  
Cell Engraftment

Abstract To study the effects of feline leukemia virus (FeLV) on the hematopoietic microenvironment, a two-step feline long-term marrow culture (LTMC) system was developed and characterized. The adherent, stromal layer of these cultures is composed of fibroblastoid cells (50% to 80%), macrophages (10% to 30%), fat cells (10% to 20%), and large, polygonal cells that express muscle actin (1% to 2%). When fresh, enriched marrow mononuclear cells (MMNC) were added to 3-week-old irradiated stromal cultures, nonadherent erythroid progenitors (BFU-E) and granulocyte/macrophage progenitors (CFU-GM) could be detected for up to 5 and 12 weeks, respectively. LTMC stromal layers established from marrow cells from cats viremic with either a nonpathogenic strain of FeLV (FeLV-A/61E) or the anemogenic strain FeLV-C/Sarma were morphologically equivalent to uninfected LTMC stromal layers, although more than 80% of the stromal cells expressed FeLV gag protein. When FeLV-infected stromal cultures were recharged with uninfected MMNC, altered patterns of hematopoiesis were observed, compared with recharged, uninfected stromal cultures. In cultures with infected stroma, fewer nonadherent cells (NAC), nonadherent BFU-E, and nonadherent CFU-GM were detected during the first 4 to 5 weeks after recharge. In contrast, greater numbers of NAC and nonadherent CFU-GM were found from weeks 5 to 12 after recharge. When FeLV-infected stromal cultures were recharged with MMNC from a cat heterozygous for the X-chromosome-linked enzyme glucose-6-phosphate dehydrogenase (G-6- PD), the percentage of nonadherent CFU-GM expressing the domestic type G-6-PD isoenzyme remained stable over time (mean % domestic [%d], 53% +/- 3%), and was equivalent to that of nonadherent CFU-GM maintained in uninfected cultures (mean %d, 56% +/- 3%), indicating that clonal drift or clonal selection was not responsible for the enhanced maintenance of CFU-GM. Furthermore, as only 10% to 20% of recharged hematopoietic cells became infected with FeLV in vitro, it is unlikely that the altered pattern was due to progenitor infection. We hypothesize that the increase in NAC and nonadherent CFU-GM in FeLV-infected cultures resulted from enhanced growth factor production by stromal cells. The two-step LTMC system may facilitate the characterization of stromal- derived factors that affect progenitor cell engraftment and proliferation.

scholarly journals Absence of the Adaptor Protein PEA-15 Is Associated with Altered Pattern of Th Cytokines Production by Activated CD4+ T Lymphocytes In Vitro, and Defective Red Blood Cell Alloimmune Response In Vivo

PLoS ONE ◽  
2015 ◽  
Vol 10 (8) ◽  
pp. e0136885 ◽  
Author(s):  
Stéphane Kerbrat ◽  
Benoit Vingert ◽  
Marie-Pierre Junier ◽  
Flavia Castellano ◽  
François Renault-Mihara ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Adaptor Protein

ASPIRIN MODIFIES RED BLOOD CELL BEHAVIOUR (RBC) IN THE PLATELET-RBC INTERACTION

1987 ◽  
Author(s):  
M T Santos ◽  
J Aznar ◽  
J Valles ◽  
J L Perez-Reguejo
Keyword(s):  
Single Dose ◽  
Blood Cell ◽  
Platelet Activation ◽  
Red Blood Cell ◽  
Normal Subjects ◽  
Antithrombotic Agent ◽  
Cell Behaviour ◽  
Insight Into

RBC stimulate the initial stages of platelet activation by collagen as evaluated by the BASIC wave (Perez-Requejo et al. Thromb Haemostas 54:799 1985). In order to get some insight into the mechanisms of platelet-RBC interactions, a BASIC wave was induced by lug/ml of collagen after mixing "in vitro" platelets and RBC obtained both before and two hours after a single dose of 500 mg of ASA from normal subjects. The TXB2 formed was also evaluated. The results show (Table) that non aspirinized RBC (non-ASA-RBC) increase the BASIC wave intensity of aspirinized platelets (ASA-PRP) by a cyclooxygenase-independent pathway since no increase in TXB2 was observed (Exp 1), while both non-ASA-RBC (Exp 2) and ASA-RBC (Exp 3) activate non-ASA platelets with theparticipation of the cyclooxygenase system, since an increase in TXA2 was found.A comparison of the effect of non-ASA-RBC (Exp 1) and ASA-RBC (Exp 4) on aspirinized platelets shows that ASA modifies the RBC behaviour associated with estimulation of platelets by a cyclooxygenase-independent pathway. This effect of ASA on RBC is nottransient and lasts at least 48 hours after ASA ingestion. In addition, when asmall proportion of nonASA platelets (10%) is mixed with aspirinized platelets(90%) and ASA-RBC - a situation that can be encountered "in vivo" inthe hours following ASA ingestion - the intensity of the BASIC wave is 89% of that obtained when all the platelets are non aspirinized. This RBC effect on the mixtureof ASA and nonASA platelets, may help explain the sometimes contradictory effect of ASA as an antithrombotic agent.

The Presence of Novel Amino Acids in the Cytoplasmic Domain of Stem Cell Factor Results in Hematopoietic Defects inSteel17H Mice

Blood ◽  
1999 ◽  
Vol 94 (6) ◽  
pp. 1915-1925 ◽  
Author(s):  
Reuben Kapur ◽  
Ryan Cooper ◽  
Xingli Xiao ◽  
Mitchell J. Weiss ◽  
Peter Donovan ◽  
...  
Keyword(s):  
Amino Acids ◽  
Bone Marrow ◽  
Biological Activity ◽  
Stem Cell ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Stem Cell Factor ◽  
Cytoplasmic Domain

Abstract Stem cell factor (SCF) is expressed as an integral membrane growth factor that may be differentially processed to produce predominantly soluble (S) (SCF248) or membrane-associated (MA) (SCF220) protein. A critical role for membrane presentation of SCF in the hematopoietic microenvironment (HM) has been suggested from the phenotype of the Steel-dickie(Sld) mice, which lack MA SCF, and by studies performed in our laboratory (and by others) using long-term bone marrow cultures and transgenic mice expressing different SCF isoforms.Steel17H (Sl17H) is an SCF mutant that demonstrates melanocyte defects and sterility in males but not in females. The Sl17H allele contains a intronic mutation resulting in the substitution of 36 amino acids (aa’s) in the SCF cytoplasmic domain with 28 novel aa’s. This mutation, which affects virtually the entire cytoplasmic domain of SCF, could be expected to alter membrane SCF presentation. To investigate this possibility, we examined the biochemical and biologic properties of the Sl17H-encoded protein and its impact in vivo and in vitro on hematopoiesis and on c-Kit signaling. We demonstrate that compound heterozygous Sl/Sl17H mice manifest multiple hematopoietic abnormalities in vivo, including red blood cell deficiency, bone marrow hypoplasia, and defective thymopoiesis. In vitro, both S and MA Sl17H isoforms of SCF exhibit reduced cell surface expression on stromal cells and diminished biological activity in comparison to wild-type (wt) SCF isoforms. These alterations in presentation and biological activity are associated with a significant reduction in the proliferation of an SCF-responsive erythroid progenitor cell line and in the activation of phosphatidylinositol 3-Kinase/Akt and mitogen-activated protein-Kinase signaling pathways. In vivo, transgene expression of the membrane-restricted (MR) (SCFX9/D3) SCF in Sl/Sl17H mutants results in a significant improvement in peripheral red blood cell counts in comparison toSl/Sl17H mice.

Pathophysiology of Thrombocytopenia and Anemia in Mice Lacking Transcription Factor NF-E2

Blood ◽  
1999 ◽  
Vol 94 (9) ◽  
pp. 3037-3047 ◽  
Author(s):  
Jack Levin ◽  
Jin-Peng Peng ◽  
Georgiann R. Baker ◽  
Jean-Luc Villeval ◽  
Patrick Lecine ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Fetal Life ◽  
Wild Type ◽  
Cell Lineages ◽  
Cell Fragments ◽  
Proliferation Potential

Abstract Expression of the p45 subunit of transcription factor NF-E2 is restricted to selected blood cell lineages, including megakaryocytes and developing erythrocytes. Mice lacking p45 NF-E2 show profound thrombocytopenia, resulting from a late arrest in megakaryocyte differentiation, and a number of red blood cell defects, including anisocytosis and hypochromia. Here we report results of studies aimed to explore the pathophysiology of these abnormalities. Mice lacking NF-E2 produce very few platelet-like particles that display highly disorganized ultrastructure and respond poorly to platelet agonists, features consistent with the usually lethal hemorrhage in these animals. Thrombocytopenia was evident during fetal life and was not corrected by splenectomy in adults. Surprisingly, fetal NF-E2–deficient megakaryocyte progenitors showed reduced proliferation potential in vitro. Thus, NF-E2 is required for regulated megakaryocyte growth as well as for differentiation into platelets. All the erythroid abnormalities were reproduced in lethally irradiated wild-type recipients of hematopoietic cells derived from NF-E2-null fetuses. Whole blood from mice lacking p45 NF-E2 showed numerous small red blood cell fragments; however, survival of intact erythrocytes in vivo was indistinguishable from control mice. Considered together, these observations indicate a requirement for NF-E2 in generating normal erythrocytes. Despite impressive splenomegaly at baseline, mice lacking p45 NF-E2 survived splenectomy, which resulted in increased reticulocyte numbers. This reveals considerable erythroid reserve within extra-splenic sites of hematopoiesis and suggests a role for the spleen in clearing abnormal erythrocytes. Our findings address distinct aspects of the requirements for NF-E2 in blood cell homeostasis and establish its roles in proper differentiation of megakaryocytes and erythrocytes.

Abnormal Erythropoiesis in Microgravity.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3701-3701 ◽  
Author(s):  
Kun Xu ◽  
Keith V. Holubec ◽  
John E. Love ◽  
Thomas J. Goodwin ◽  
Arthur J. Sytkowski
Keyword(s):  
Blood Cell ◽  
Cell Line ◽  
Red Blood Cell ◽  
Bone Marrow Cells ◽  
Cell Mass ◽  
Erythroid Cell ◽  
Specific Marker ◽  
Murine Erythroleukemia

Abstract Humans and experimental animals subjected to microgravity, such as experienced during space flight, exhibit alterations in erythropoiesis, including changes in red blood cell morphology, survival and a reduction in red blood cell mass. Some of these alterations have been attributed to a disruption of normal in vivo erythropoietin physiology. However, human bone marrow cells grown on orbit showed a profound reduction in the number of erythroid cells, suggesting a cellular component. We now report the results of a study carried out on orbit on the International Space Station (ISS UF-1) in which an erythroid cell line was induced to differentiate. Rauscher murine erythroleukemia cells, a continuous cell line that can undergo erythropoietin (Epo)- or chemical-induced differentiation similar to normal erythropoiesis, were cultured for 6 days either in microgravity on board the ISS or on earth and then for 3 days in the absence or presence of 50 U Epo/ml or 0.7% dimethyl sulfoxide (DMSO). The cells were fixed, stored on orbit and returned to earth for study. Compared to ground-based controls, cells cultured in microgravity exhibited a greater degree of differentiation (hemoglobinization) (p<0.01). However, TER-119 antigen, a specific marker of the late stages of murine erythroid differentiation, was not detected on the surface of cells grown in microgravity. A significantly higher percentage (p<0.05) of cell clusters formed on orbit, whereas actin content appeared reduced. Furthermore, there was a more profound loss of actin stress fibers in microgravity following Epo or DMSO treatment. These results demonstrate abnormal erythropoiesis in vitro in microgravity and are consistent with the hypothesis that erythropoiesis is affected by gravitational forces at the cellular level.(Supported by NASA Grants NAG9-1368 and NAG2-1592 to AJS)

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