Specific role of manganese and magnesium on RNA synthesis in rabbit bone marrow erythroid cell nuclei

1988 ◽  
Vol 16 (3) ◽  
pp. 203-219 ◽  
Author(s):  
Moon K. Song ◽  
John A. Hunt
Keyword(s):  
Bone Marrow ◽  
Rna Synthesis ◽  
Specific Role ◽  
Erythroid Cell ◽  
Cell Nuclei ◽  
Rabbit Bone

scholarly journals Elucidating the Role of IL6 in Stress Erythropoiesis and in the Development of Anemia Under Inflammatory Conditions

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 940-940
Author(s):  
Sayantani Sinha ◽  
Ritama Gupta ◽  
Jianbing Zhang ◽  
Amaliris Guerra ◽  
Ping La ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Bone Marrow ◽  
Inflammatory Cytokines ◽  
Reticulocyte Count ◽  
Erythroid Cell ◽  
Deficiency Anemia ◽  
Iron Dextran ◽  
Erythroid Cells ◽  
Second Wave

Anemia of inflammation, also known as anemia of chronic disease is the second most common anemia after iron deficiency anemia. The predominant regulators of AI are the cytokine-interleukin-6 (IL6) and the hormone hepcidin (Hamp). IL6 has been implicated in inducing expression of hepcidin. Published data from our lab have shown that lack of IL6 or hepcidin in knockout mouse models (IL6-KO and Hamp-KO) injected with the heat-killed pathogen Brucella abortus(BA) results in recovery from anemia but interestingly the pattern of the recovery was different in IL6-KO and Hamp-KO mice, suggesting that the two proteins contribute independently to AI. Here, we validated the independent role of IL6 and Hamp in AI by generating a double-knockout (DKO) mouse model lacking the expression of both. In the first few days following BA administration, we observed severe reduction in the total number of BM cells in each model followed by a slow recovery in erythroid and multilineage hematopoietic cells. The recovery, initially, was more sustained in the BA-treated-DKO model. In particular, in the first week, BA-treated-DKO mice showed an increased number of erythroblasts in the bone marrow (BM) and spleen as seen in comparison to IL6-KO and Hamp-KO. IL6-KO mice showed an intermediate recovery profile when compared to DKO and Hamp-KO, the last one showing the worst profile in the BM. Interestingly, when the reticulocyte count in the DKO mice was compared to that of IL6-KO and Hamp-KO mice, it showed a biphasic trend, with a significant increase in number during the 2nd week, followed by a significant reduction during the 3rd week. We hypothesized that the initial surge in reticulocyte count in DKO was due to lack of hepcidin, which increases iron availability to erythroid cells, and concurrent lack of IL6, which favors BM erythropoiesis in presence of inflammatory stimuli. However, we also speculated that the excess of iron (as NTBI), which accumulates during the first two weeks, leads to oxidative stress and erythroid cell death in presence of inflammatory cytokines, despite the absence of IL6. We also surmised that, during the second week, a second wave of inflammatory cytokines is triggered by the adaptive response in response to the BA that would explain the negative effect on erythropoiesis after the initial recovery. To assess this hypothesis, we utilized an inflammation panel to analyze the cytokine expression in WT animals treated with PBS or BA at 6 hours, 24 hours and then around ~2 weeks. The cytokine levels were normalized after 24 hours. However, around two weeks, we observed a novel surge of cytokines such as IFN-g and TNFa in the BA treated mice, indicating their role in innate (immediate effect; 6 hours) and adaptive immune response, which activated a second wave of inflammation (around 2 weeks, during the recovery of hematopoiesis in the BM). Interestingly, while we observed oxidative stress and defective erythropoiesis in the bone marrow, this was not seen in the spleen, where increased and extramedullary erythropoiesis sustained some level of RBC production. Since the BA-treated-IL6-KO did not show any major defect in the BM after two weeks, we challenged them with administration of iron dextran. Upon treatment, also the IL6-KO mice treated with both BA and iron dextran shown increased production of reactive oxygen species as well as a defect in bone marrow erythropoiesis, similarly as in DKO or Hamp-KO mice, thereby explaining the plausible reason of reduced erythropoiesis in the bone-marrow. Furthermore, to identify mechanisms leading to oxidative stress, we established an in-vitro culture system where primary murine bone marrow cells were cultured for 18-20 hours in presence of serum isolated after 6hrs from either PBS treated or BA treated C57BL/6 mice. With the help of confocal microscopy, we observed an increase in mitochondrial superoxide in the cells treated with BA serum; interestingly we have also seen a decrease in Ter 119 population in the cells cultured with BA treated serum implicating that the erythroid cells are dying. To further investigate the downstream players related to the death of erythroid progenitors we are currently investigating the role caspase 1 (a major regulator in pyroptosis) and Gata-1. In conclusion, this study is elucidating some of the mechanisms associated with the anemia triggered by inflammation with the potential to identify new targets and treatments. Disclosures Rivella: Disc medicine, Protagonist, LIPC, Meira GTx: Consultancy; Meira GTx, Ionis Pharmaceutical: Membership on an entity's Board of Directors or advisory committees.

Application of Multiparameter Flow Cytometry for the Identification of Dysplasia in Granulocytic, Monocytic, and Erythrocytic Lineages and Blasts in Patients with Myelodysplastic Syndromes.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2615-2615
Author(s):  
Wolfgang Kern ◽  
Claudia Schoch ◽  
Susanne Schnittger ◽  
Torsten Haferlach
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Myelodysplastic Syndromes ◽  
Erythroid Cell ◽  
Multiparameter Flow Cytometry ◽  
Cell Populations ◽  
Aberrant Expression ◽  
Hla Dr ◽  
Cd16 Expression

The diagnosis and classification of myelodysplastic syndromes (MDS) are based on cytomorphology (CM) and cytogenetics. A high degree of experience in CM is required to allow the accurate identification of dysmyelopoiesis and quantification of bone marrow blasts. The identification of dysplastic features in all lineages by multiparameter flow cytometry (MFC) has been shown feasible. To further analyze the potential role of MFC in the diagnostic work-up of MDS we analyzed 224 bone marrow samples from patients with suspected of proven MDS by MFC, CM, and cytogenetics in parallel. Blast counts as determined by CM and MFC, respectively, ranged from 0% to 21% (median, 5%) and from 0% to 33% (median, 4%; correlation: r=0.192, p=0.018). The median number of aberrant features detected by MFC were 0 for blasts (range, 0 to 4), 2 for granulocytes (0 to 7), 1 for monocytes (0 to 5), and 0 for erythrocytes (0 to 2). The most frequent dysplastic features observed in the blast populations included aberrant coexpression of CD11b (20.5%), CD15 (14.3%) and CD64 (14.3%). The most frequent dysplastic features observed in the granulocytic cell populations included reduced side-scatter signal corresponding to hypogranulation (71.4%), aberrant coexpression of CD56 (29.0%), aberrant pattern of CD13/CD16 expression (26.3%), aberrant pattern of CD11b/CD16 expression (25.9%), reduced expression of CD64 (17.0%), and aberrant expression of HLA-DR (14.7%). The most frequent dysplastic features observed in the monocytic cell populations included aberrant coexpression of CD56 (31.3%), aberrant coexpression of CD16 (26.3%), an aberrant pattern of CD11b/HLA-DR expression (6.7%), and aberrant coexpression of CD2 (5.8%). The most frequent dysplastic features observed in the erythroid cell populations included an aberrantly strong expression of CD71 and CD235a (23.7%), a lack of CD71 expression (10.7%), and an aberratly homogeneous expression of CD71 (7.1%). The presence of dysplastic features by CM as well as the presence of cytogenetic aberrations tended to be associated with a higher number of dysplastic features by MFC. These data suggest that the identification of dysplastic features by MFC is feasible although there is a large heterogeneity in aberrantly expressed antigens. Thus, a comprehensive panel of antibodies must be applied to allow the detection of dysplasia. Future studies will define the role of MFC in optimizing the diagnosis of MDS in cooperation with CM and cytogenetics.

scholarly journals Activation of JAK/STAT Signaling in Megakaryocytes Is Necessary and Sufficient for Myeloproliferation In Vivo

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 949-949
Author(s):  
Q. Jeremy Wen ◽  
Brittany Woods ◽  
Qiong Yang ◽  
Chiu Sophia ◽  
Gu Lillu ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Diphtheria Toxin ◽  
Bone Marrow Cells ◽  
Erythroid Cell ◽  
Spleen Weight ◽  
Wild Type ◽  
Myeloid Progenitor

Abstract Aberrant megakaryopoiesis is a hallmark of the myeloproliferative neoplasms (MPN). It is has been long known that abnormal megakaryocytes secrete elevated levels of cytokines such as TGFβ, resulting in pathologies including bone marrow fibrosis. Two recent studies showed that megakaryocytes regulate the quiescence of HSCs, raising the possibility that megakaryocytes may promote the MPNs by influencing the biology of non-malignant HSCs. However, the mechanism by which megakaryocytes regulate the initiation and progression of MPNs is largely unknown. To study the role of megakaryocytes in the MPNs, we analyzed the phenotype of PF4-Cre/Jak2V617F mice in which Jak2 is expressed in the megakaryocyte lineage from the endogenous locus, in contrast to previous studies, which used transgenic models. Selective activation of Jak2V617F was confirmed by allele-specific qPCR. CD41+ cells were positive for mutant Jak2, whereas sorted stem/progenitor cells and erythroid cells were Jak2 wild-type. Furthermore, flow cytometry showed that Stat5 activation was present in megakaryocytes, but not in erythroid or myeloid cells. Activation of JAK-STAT signaling caused an expansion of megakaryocytes in the bone marrow and spleen and a modest increase in the platelet count. Surprisingly, PF4-Cre/Jak2V617F mice also displayed a robust expansion of TER119(low)/CD71(high) and TER119(high)/CD71(high) red cells in the spleen, increased hematocrit and splenomegaly. Histological examination of the spleen revealed expansion of the erythroid lineage coupled with disrupted splenic architecture and fibrosis. This PV-like phenotype was fully penetrant and comparable to that of Vav-Cre/Jak2V617F mice, which express mutant Jak2 in all hematopoietic lineages. Profiling of hematopoietic progenitors by flow cytometry demonstrated that myeloid progenitor populations were expanded and skewed toward the erythroid-megakaryocyte lineage with a significant increase in Pre Meg-E, Pre CFU-E and MKPs in the PF4Cre/Jak2V617F mice. In addition, LSK cells were increased in both the bone marrow and spleen. Cytokine profiling of the plasma revealed increased levels of several cytokines, including Il-6, which is known to be upregulated in human JAK2 mutant PV megakaryocytes. Significant increases in Cxcl1, Cxcl2, and Ccl11 were also detected. Real-time qPCR analysis confirmed increased expression of these cytokines/chemokines in Jak2V617F-mutant CD41+ cells. Furthermore, IL6 treatment increased EPO-dependent colony formation of wild type LSKs and MEPs, and also enhanced expression of the erythroid cell markers CD71 and Ter119. To further explore the role of megakaryocytes in the MPNs, we used a strategy in which expression of the diphtheria toxin receptor (DTR) sensitizes cells to diphtheria toxin (DT). We transduced c-Kit+ cells from PF4-Cre/iDTR+/- mice with MPLW515L and transplanted the cells to irradiated mice. As expected, both iDTR+/- and PF4-Cre/iDTR+/- mice developed a PMF-like phenotype, including leukocytosis, thrombocytosis, splenomegaly and myelofibrosis (Fig 1). Treatment of these animals with DT caused significant reductions in megakaryocytes in the bone marrow and spleen as well as a decrease in the platelet count of PF4-Cre/iDTR+/- mice. Of note, DT also significantly reduced the white count and spleen weight, while restoring splenic architecture. PF4Cre/iDTR+/- mice also showed significant reduction of c-Kit+ myeloid progenitor cells. Therefore, depletion of megakaryocytes significantly attenuated the disease phenotype of MPLW515L induced MPN in vivo. Together, these two model systems reveal that JAK2 activation in megakaryocytes is sufficient and necessary for MPNs and support the development of megakaryocyte differentiation therapy in the disease. Moreover our data resonate with studies in MPN patients in which a JAK2V617F low allele burden in the setting of full-blown, clinical MPN. figure 1 Depletion of megakaryocytes attenuated the MPN phenotype induced by MPLW515L. c-Kit+ bone marrow cells of IDTR+/- mice with or without PF4Cre were transduced with retroviruses carrying MPLW515L. Injection of diphtheria toxin (DT) was initiated on day 28 post-transplant. Depletion of megakaryocytes by DT reduced platelet and white count (A, B), decreased spleen weight (C) and reduced megakaryocyte and erythroid cell infiltration in the spleen (D). *, p<0.05, **, p<0.01. figure 1. Depletion of megakaryocytes attenuated the MPN phenotype induced by MPLW515L. c-Kit+ bone marrow cells of IDTR+/- mice with or without PF4Cre were transduced with retroviruses carrying MPLW515L. Injection of diphtheria toxin (DT) was initiated on day 28 post-transplant. Depletion of megakaryocytes by DT reduced platelet and white count (A, B), decreased spleen weight (C) and reduced megakaryocyte and erythroid cell infiltration in the spleen (D). *, p<0.05, **, p<0.01. Disclosures Levine: Novartis: Consultancy; Qiagen: Membership on an entity's Board of Directors or advisory committees.

scholarly journals Effect of Erythropoietin on the Expression of Murine Transferrin Receptor 2

2021 ◽  
Vol 22 (15) ◽  
pp. 8209
Author(s):  
Betty Berezovsky ◽  
Martin Báječný ◽  
Jana Frýdlová ◽  
Iuliia Gurieva ◽  
Daniel Wayne Rogalsky ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Transferrin Receptor ◽  
Erythroid Cell ◽  
Murine Bone Marrow ◽  
Hepcidin Expression ◽  
Stress Erythropoiesis ◽  
Order Of Magnitude ◽  
Hepcidin Mrna ◽  
Transferrin Receptor 2

Erythropoietin (EPO) downregulates hepcidin expression to increase the availability of iron; the downregulation of hepcidin is mediated by erythroferrone (ERFE) secreted by erythroblasts. Erythroblasts also express transferrin receptor 2 (TFR2); however, the possible role of TFR2 in hepcidin downregulation is unclear. The purpose of the study was to correlate liver expression of hepcidin with the expression of ERFE and TFR2 in murine bone marrow and spleen at 4, 16, 24, 48, 72 and 96 h following administration of a single dose of EPO. Splenic Fam132b expression increased 4 h after EPO injection; liver hepcidin mRNA was decreased at 16 h. In the spleen, expression of TFR2 and transferrin receptor (TFR1) proteins increased by an order of magnitude at 48 and 72 h after EPO treatment. The EPO-induced increase in splenic TFR2 and TFR1 was associated with an increase in the number of Tfr2- and Tfr1-expressing erythroblasts. Plasma exosomes prepared from EPO-treated mice displayed increased amount of TFR1 protein; however, no exosomal TFR2 was detected. Overall, the results confirm the importance of ERFE in stress erythropoiesis, support the role of TFR2 in erythroid cell development, and highlight possible differences in the removal of TFR2 and TFR1 from erythroid cell membranes.

The MAPK ERK1 Is a Sensor of the Steady-State Splenic Erythropoiesis.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 73-73
Author(s):  
Soizic Guihard ◽  
Denis Clay ◽  
Laurence Cocault ◽  
Paule Opolon ◽  
Michele Souyri ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Cell Surface ◽  
Mapk Pathway ◽  
Surface Expression ◽  
Specific Role ◽  
Cell Surface Expression ◽  
Wild Type ◽  
Erk Mapk

Abstract Abstract 73 In different culture models, conflicting results have been obtained with respect to the role of the ERK/MAPK pathway and the ERK kinases on erythropoiesis. There is no in vivo experimental data on the role of these kinases in adult erythropoeisis. The existence of two ERK isoforms (ERK1 and ERK2) suggests that they could play specific role, based on their expression, their activation level and/or the ratio between both of them. The ERK1−/− mice were used to study this hypothesis. Increased number of circulating erythrocytes, increased hemoglobin level and hematocrit were found in these mice. The deletion of ERK1 leads to an uncontrolled splenic erythropoiesis while the bone marrow erythropoiesis remains normal. The ERK1−/− mice display splenomegaly characterized by a marked expansion of the red pulp and an increased number in basophilic (Ery.A) and late basophilic (Ery.B) erythroblasts. This impaired erythropoiesis in ERK1−/− mice is cell autonomous as shown by bone marrow transplantation experiments. This splenic erythropoiesis is not due to an overexpression or overactivation of the ERK2 isoform in erythroblasts. It has been shown that Fas-mediated apoptosis of erythroblasts would limit the basal erythropoietic rate. In ERK1−/− mice, Ery.A expansion is associated with a decrease in cell surface expression of both Fas and FasL as compared with wild-type mice. This fall in Fas/FasL expression is correlated with a decrease in Annexin V binding on splenic Ery.A and Ery.B. In addition, cell cycle analysis revealed an increased S-phase in ERK1−/− Ery.A cells compared with wild-type Ery.A. In conclusion, these data demonstrate for the first time the in vivo involvement of the ERK/MAPK pathway in adult splenic erythropoiesis and underlies the specific role of ERK1 in this function. By regulating the cell surface expression of Fas and FasL on splenic erythroblasts, ERK1 acts as a sensor of the basal erythropoietic rate. Disclosures: No relevant conflicts of interest to declare.

Analysis of TIF1gamma Conditional Knockout Establishes a Requirement for the Differentiation of Multiple Hematopoietic Lineages

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 744-744
Author(s):  
Xiaoying Bai ◽  
Jennifer Trowbridge ◽  
Joseph Lee ◽  
Stuart H. Orkin ◽  
Leonard I. Zon
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
Board Of Directors ◽  
Transcription Elongation ◽  
Conditional Knockout ◽  
Erythroid Cell ◽  
Advisory Committees ◽  
Equity Ownership ◽  
Differentiation And Proliferation

Abstract Abstract 744 Vertebrate hematopoiesis is regulated by cell-specific transcription factors that couple to RNA polymerase-associated basal machinery. Mutation of the chromatin factor TIF1gamma (TIF1g) gene in the zebrafish moonshine mutant causes a profound decrease in expression of most erythroid genes. Our previous work in the zebrafish system established an essential role of TIF1g in transcription elongation by coupling the SCL transcription factor complex to the transcription elongation machinery, and erythroid-specific transcription is paused in moonshine mutant (Bai et al., Cell 2010). Here we examined the role of TIF1g in murine hematopoiesis by studying conditional knockout (KO) models. Deletion of TIF1g was either induced in adult mice by Mx-Cre or during mouse development by vav-Cre. Both Cre systems induce excision at the HSC level and in all hematopoietic lineages. We observed the same trend of multi-lineage defects in both Cre lines, including decreased erythropoiesis in the bone marrow, loss of mature B cells and expansion of granulocytes. Bone marrow analysis of TIF1g-deleted mice revealed a block in erythroid differentiation starting as early as the BFU-E stage, consistent with the erythroid defect in the zebrafish moonshine mutant, confirming an evolutionarily conserved role for TIF1g in vertebrate erythropoiesis. A subset of the vav-Cre induced KO mice developed a MPD (myeloproliferative disease)-like phenotype at 1–3 months after birth, including a dramatic increase of dysplastic granulocytes in the peripheral blood and massive extramedullary hematopoiesis in spleen and liver, suggesting a requirement for TIF1g in myeloid differentiation and proliferation. Consistent with the KO mouse phenotype, we observed an increase of definitive myelopoiesis in the zebrafish TIF1g mutant. In addition, mature B cells were absent in KO mice, and this loss was observed as early as the pre-B stage, suggesting a defect occurring at the pro-B to pre-B transition. At the progenitor level, we observed an increase of GMP, MPP, and HSCs in bone marrow, suggesting that TIF1g may be required to control proliferation at the stem/progenitor cell stage or in the committed myeloid lineage. Our study reveals an essential function of TIF1g in regulating the differentiation and proliferation of multiple hematopoietic lineages. Reference Bai X, Kim J, Yang Z, Jurynec M, Akie T, et al. (2010) TIF1gamma controls erythroid cell fate by regulating transcription elongation. Cell. 142:133-43. Disclosures: Zon: FATE, Inc.: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; Stemgent: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees.

scholarly journals Degradation of cartilage proteoglycans by a neutral proteinase secreted by rabbit bone-marrow macrophages in culture

1978 ◽  
Vol 172 (2) ◽  
pp. 275-284 ◽  
Author(s):  
P Hauser ◽  
G Vaes
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Cells ◽  
Culture Media ◽  
Neutral Proteinase ◽  
Inflammatory Processes ◽  
Joint Erosions ◽  
Rabbit Bone ◽  
Cartilage Proteoglycans

When cultivated together with pieces of cartilage biosynthetically labelled with 35S in their proteoglycans, rabbit macrophages, differentiated in vitro from bone-marrow cells, cause the release of soluble 35S-labelled material into the culture medium. This process is inhibited by killing the macrophages or by cycloheximide treatment, and is due to the secretion by the cells of a metal-dependent neutral proteinase capable of degrading cartilage proteoglycan subunits into fragments of high molecular weight. Enzyme activity is optimum at about pH7, and is inhibited by EDTA, o-phenanthroline, cysteine or serum, but not by di-isopropyl phosphorofluoridate nor by 4-hydroxymercuribenzoate. The effect of EDTA is partially reversed by Co2+ or Zn2+ ions. The enzyme is eluted from Sephadex G-150 columns as a single peak of material (apparent mol.wt. 17000) that contains also most of the proteolytic activity exerted by culture media on Azocoll (denatured collagen) or on casein. The possible role of this metalloproteinase in chronic inflammatory processes is discussed, particularly in connection with joint erosions in rheumatoid arthritis.

Possible role of calcium in regulation of RNA synthesis by brain tissue cell nuclei

1981 ◽  
Vol 91 (6) ◽  
pp. 746-748 ◽  
Author(s):  
N. I. Razumovskaya ◽  
S. A. Dambinova ◽  
M. N. Demina ◽  
L. V. Govorova
Keyword(s):  
Brain Tissue ◽  
Rna Synthesis ◽  
Tissue Cell ◽  
Cell Nuclei
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