Cell-Cell Interaction in Erythropoiesis: ROLE of HUMAN MONOCYTES
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Cell-Cell Interaction in Erythropoiesis: ROLE OF HUMAN MONOCYTES John J. Rinehart, … , Bobby J. Gormus, Manuel E. Kaplan J Clin Invest. 1978;62(5):979-986. https://doi.org/10.1172/JCI109227. Erythroid burst forming units (BFU-E) are proliferative cells present in peripheral blood and bone marrow which may be precursors of the erythroid colony forming cell found in the bone marrow. To examine the possible role of monocyte- macrophages in the modulation of erythropoiesis, the effect of monocytes on peripheral blood BFU-E proliferation in response to erythropoietin was investigated in the plasma clot culture system. Peripheral blood mononuclear cells from normal human donors were separated into four fractions. Fraction-I cells were obtained from the interface of Ficoll- Hypaque gradients (20-30% monocytes; 60-80% lymphocytes); fraction-II cells were fraction-I cells that were nonadherent to plastic (2-10% monocytes; 90-98% lymphocytes); fraction-III cells were obtained by incubation of fraction-II cells with carbonyl iron followed by Ficoll-Hypaque centrifugation (>99% lymphocytes); and fraction-IV cells represented the adherent population of fraction-II cells released from the plastic by lidocaine (>95% monocytes). When cells from these fractions were cultured in the presence of erythropoietin, the number of BFU-E-derived colonies was inversely proportional to the number of monocytes present (r = −0.96, P < 0.001). The suppressive effect of monocytes on BFU-E proliferation was confirmed by admixing autologous purified monocytes (fraction-IV cells) with fraction-III cells. Monocyte concentrations of ≥20% completely suppressed BFU-E activity. Reduction in the number of plated BFU-E by monocyte dilution could not account for these findings: a 15% reduction in […] Find the latest version: https://jci.me/109227/pdf Cell-Cell Interaction in Erythropoiesis ROLE OF HUMAN MONOCYTES JOHN J. RINEHART, ESMAIL D. ZANJANI, BENET NOMDEDEU, BOBBY J. GORMUS, and MANUEL E. KAPLAN, Departments of Medicine and Physiology, Hematology Division, University of Minnesota School of Medicine and Veterans Administration Hospital, Minneapolis, Minnesota 55417 A B S T R A C T Erythroid burst forming units (BFU-E) neoplasia in which increased monocyte activity and are proliferative cells present in peripheral blood and monopoiesis also occur. bone marrow which may be precursors of the erythroid colony forming cell found in the bone marrow. To ex- INTRODUCTION amine the possible role of monocyte-macrophages in the modulation of erythropoiesis, the effect of mono- It is generally accepted that erythropoietin (Ep)l reg- cytes on peripheral blood BFU-E proliferation in re- ulates mammalian erythropoiesis (1, 2). Several lines sponse to erythropoietin was investigated in the plasma of evidence suggest that cell-cell interactions also play clot culture system. Peripheral blood mononuclear cells an important role in the production of erythrocytes. from normal human donors were separated into four Lymphocyte effects on in vivo erythropoiesis have been fractions. Fraction-I cells were obtained from the inter- observed in several animal systems. Goodman and face of Ficoll-Hypaque gradients (20-30% monocytes; Shinpock (3) showed that proliferation of parent marrow 60-80% lymphocytes); fraction-II cells were fraction-I in irradiated hybrid mice was enhanced by concomitant cells that were nonadherent to plastic (2- 10% mono- injection of parental thymus-derived cells. The degree cytes; 90-98% lymphocytes); fraction-III cells were of this enhancement was related to the number of thy- obtained by incubation of fraction-II cells with carbonyl mus-derived cells injected. A recent study (4) dem- iron followed by Ficoll-Hypaque centrifugation (>99% onstrates that the ability of the genetically normal lymphocytes); and fraction-IV cells represented the ad- (+/+) bone marrow or spleen cells to correct the macro- herent population of fraction-II cells released from the cytic anemia of W/Wv mice may be thymus-derived- plastic by lidocaine (>95% monocytes). When cells cell dependent: treatment of these donor cells with from these fractions were cultured in the presence of complement and anti-sera to the thymus-derived-cell erythropoietin, the number of BFU-E-derived colonies antigen Thy 1.2 abolishes their effect. Petrov et al. was inversely proportional to the number of monocytes (5) have shown that the transfer of lymphocytes to- present (r = -0.96, P < 0.001). The suppressive effect gether with allogeneic bone marrow cells into lethally of monocytes on BFU-E proliferation was confirmed irradiated recipient mice resulted in the inactivation of by admixing autologous purified monocytes (fraction- spleen colony forming units; this effect was not linked IV cells) with fraction-III cells. Monocyte concentra- to the H-2 histocompatibility system (6). The avail- tions of -20% completely suppressed BFU-E activity. ability of culture techniques for the study of prolifera- Reduction in the number of plated BFU-E by mono- tion and differentiation of erythropoietic precursors in cyte dilution could not account for these findings: a vitro has provided additional support for the existence 15% reduction in the number of fraction-III cells plated of regulatory processes involving cell-cell interaction resulted in only a 15% reduction in colony formation. in erythropoiesis. Thus, suppression of normal human These results indicate that monocyte-macrophages may bone marrow erythroid colony forming units (CFU-E) play a significant role in the regulation of erythropoiesis by peripheral blood lymphocytes from some patients and be involved in the pathogenesis of the hypopro- with Diamond-Blackfan syndrome (7) and aplastic liferative anemias associated with infection and certain anemia has been described (8). Steinberg et al. have 'Abbreviations used in this paper: BFU-E, erythroid burst Received for publication 5 December 1977 and in revised forming units; CFU-E, erythroid colony forming units; EC, form IO July 1978. erythroid colonies; Ep, erythropoietin; F, fraction. The Journal of Clinical Investigation Volume 62 November 1978 *979-986 979 also described suppression of erythroid burst forming Heporinized Blood units (BFU-E) by circulating thymus-derived cells from patients with Diamond-Blackfan syndrome (9). Ficoll- Hypaque In a preliminary study of human peripheral blood erythroid precursors, we used the plasma clot culture system (10) and previously described cell separation Interface cells = Fraction I (30% Monocytes) techniques (11). As others have shown, we found a highly variable number of BFU-E/105 mononuclear cells Fraction I (in RMPI, 20% sera) incubated in culture dishes and washed from normal donors. We undertook a study of this vari- ability and found that normal BFU-E proliferation was cells Non-AdherentNon-Adherentcellscela(FractionrAdherentIe obtained by lidocaine- FIZrelease modulated by monocytes. When procedures conducive (6% Monocytes) (95% to the preservation of circulating monocytes were em- Monocytes) ployed in the preparation of blood mononuclear cells, the proliferation and (or) differentiation of BFU-E was Fraction II, incubated with carbonyl iron found to be inversely related to the number of mono- cytes present. Thus, BFU-E proliferation was com- Ficoll - Hypaque pletely inhibited in the presence of >20% monocytes. Removal of monocytes resulted in marked enhance- Interface cells = Fraction m (0.6% Monocytes) ment of BFU-E proliferation. Addition of purified mono- FIGURE 1 Schematic representation of cell separation. See cytes to monocyte-depleted mononuclear cells in- text for details of the procedure. hibited BFU-E proliferation. cells were suspended to 0.5-4 x 106/1.1 ml of media com- METHODS posed of 0.3 ml fetal calf serum, 0.1 ml bovine serum al- bumin (10% in phosphate-buffered saline), 0.1 ml L-asparigine After informed consent was obtained, blood was drawn from (2 mg/ml NCTC-109, Hyland Laboratories, Los Angeles, normal human donors, heparinized, and separated by a mod- Calif.), 0.1 ml a-thioglycerol (10 mM, NCTC-109), 0.1 ml ification of the isopycnic gradient technique previously de- citrated bovine plasma, and contained 0.5, 1, 2, 4, or 6 U of scribed (11). Briefly, blood was diluted 1:1 with Seligman's Ep. For each experimental point eight 0.1-ml/well cultures balanced salt solution (Ficoll, Pharmacia Fine Chemicals, were established and incubated at 37°C in humidified air with Piscataway, N. J.; Hypaque, Winthrop Laboratories, Sterling 5% CO2 for 14 days. Clots were then removed, placed on Drug Co., New York), (1.077 sp gr), and centrifuged glass slides,fixed with glutaraldehyde, and stained with ben- at 400 g for 25 min at 15°C. In specific experiments to be zidine. described, isopycnic gradient centrifugations were performed Ep was assayed as follows. Female CF-I mice were made by varying the time and temperature and by using Ficoll- polycythemic by exposure to 0.4 atmosphere barometric pres- Paque (Pharmacia Fine Chemicals) (1.077 sp gr) instead sure 19 h/day for a total of 219 h. Animals were then injected of Ficoll-Hypaque. Interface cells, designated as frac- i.p. with different volumes of media (adjusted to 1 ml with tion (F)-I, were utilized in cultures or were further separated saline) to be assayed for Ep or with standard quantities of into three cell fractions (Fig. 1); F-I cells were adjusted to Ep on days 5 and 6 posthypoxia. Radioiron (0.5 S.Ci/mouse) 1.5 x 106 monocytes/ml of RPMI containing 20% autologous was given i.v. on day 7 and the percent erythrocyte-_9Fe uptake sera. The percentage of monocytes in each fraction was de- was determined on day 9. 6-10 mice were used to test each termined by latex phagocytosis, Sudan black positivity and sample and standard; the units of Ep in each sample were morphology of Giemsa-stained cytocentrifuge preparation. determined from a standard curve as previously described (13). The values obtained by these techniques correlated closely Materials for these experiments were obtained as follows: (±+3%).