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Biomedical subjects

F C Monette

Publications and source records attributed to F C Monette.

At least 19 recordsLinked to original sources
PubMed1988

Molecularly characterized factors governing the growth of murine multipotent stem cells in serum-depleted marrow cultures.

The growth requirements of normal murine marrow-derived multipotent stem cells (CFU-GEMM) in a simple clonal cell culture system substantially devoid of exogenous serum proteins was assessed. The ability of murine interleukin-3 (Il-3), recombinant human erythropoietin (rEPO), and a crystalline preparation of the protoporphyrin hemin to support colony growth in "serum-free" cultures was examined by titration. The results suggest that both Il-3 and hemin are limiting for multipotential colony growth in "serum-free" cultures, but that EPO is not. In addition, the 'sensitivity' of CFU-GEMM to each growth factor appeared to increase in the "serum-free" environment as evidenced by a "shift-to-the-left" in all the titration curves. Nearly half of the GEMM colonies grew to full maturity in the absence of exogenous EPO. Given the optimal concentration of each growth factor, high colony growth was consistently observed in the "serum-free" cultures, with a range from 65% to 119% of the serum control level. It is therefore concluded that supplementation of murine marrow cultures with Il-3 and hemin alone may provide the necessary setting for studying the factors which modulate the growth of multipotent stem cells in a serum-free environment.

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PubMed1988

Growth of murine multipotent stem cells in a simple "serum-free" culture system: role of interleukin-3, erythropoietin, and hemin.

The growth requirements of normal murine marrow-derived multipotent stem cells (CFU-GEMM) in a simple clonal cell culture system substantially devoid of exogenous serum proteins was assessed. The ability of murine interleukin-3 (Il-3), recombinant human erythropoietin (rEPO), and a crystalline preparation of the protoporphyrin hemin to support colony growth in "serum-free" cultures was examined by titration. The results suggest that both Il-3 and hemin are limiting for multipotential colony growth in "serum-free" cultures, but that EPO is not. In addition, the "sensitivity" of CFU-GEMM to each growth factor appeared to increase in the "serum-free" environment as evidenced by a "shift-to-the-left" in all the titration curves. Nearly half of the GEMM colonies grew to full maturity in the absence of exogenous EPO. Given the optimal concentration of each growth factor, high colony growth was consistently observed in the "serum-free" cultures, with a range from 65% to 119% of the serum control level. It is therefore concluded that supplementation of murine marrow cultures with Il-3 and hemin alone may provide the necessary setting for studying the factors that modulate the growth of multipotent stem cells in a serum-free environment.

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PubMed1988

Hemin acts synergistically with interleukin-3 to promote the growth of multipotent stem cells (CFU-GEMM) in "serum-free" cultures of normal murine bone marrow.

The role of hemin (iron protoporphyrin 9) in the enhancement of interleukin-3 (IL-3)-stimulated multipotent stem cell colony formation was assessed in both serum-containing as well as in "serum-free" marrow culture systems. A greater than 7-fold enhancement in colony number was observed when cultures were supplemented with both IL-3 and hemin compared with either factor alone. In addition, this effect was observed over a wide concentration range. Hemin by itself failed to promote CFU-GEMM in the "serum-free" marrow culture system. The results suggest that hemin acts synergistically with IL-3 to promote the growth of CFU-GEMM in a dose-dependent manner.

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PubMed1987

Sensitivity of murine multipotential stem cell colony (CFU-GEMM) growth to interleukin-3, erythropoietin, and hemin.

The in vitro growth of murine marrow-derived CFU-GEMM in response to partially purified preparations of interleukin-3 and erythropoietin was assessed in the presence of hemin. Although CFU-GEMM exhibited a near-absolute requirement for interleukin-3, some colony growth was observed in the absence of exogenous erythropoietin. Erythropoietin was nevertheless capable of further stimulating CFU-GEMM growth in the presence of optimal concentrations of interleukin-3 and hemin. Optimal concentrations of all three factors allowed at least a 60% reduction in the serum concentration without an effect on colony numbers or their detection efficiency. Furthermore, nearly half the colonies continued to grow without the addition of serum, suggesting that hemin supplementation, along with interleukin-3 and erythropoietin, may provide the basis for a relatively simple serum-free culture system for murine CFU-GEMM.

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PubMed1985

Effect of rabbit antimouse brain serum on marrow cells capable of curing W/Wv mice.

The W/Wv mouse has a recessively inherited defect in hematopoietic stem cells (HSC) but can be cured of its hematopoietic abnormalities by infusion of marrow from a co-isogeneic, +/+ mouse. The "curative" cell for the W/Wv is thought to be a subcompartment of the HSC that is capable of forming hematopoietic spleen colonies (CFU-S) in irradiated mice. The curative HSC must have a very high proliferative potential and it is known that HSC with variable degrees of proliferative potential are found within the CFU-S compartment. Rabbit antimouse brain serum (RAMBS) was used to treat +/+ marrow and its effect upon CFU-S and upon curative cells was compared with the effect of normal rabbit serum (NRS) or of sham treatment. CFU-S were reduced to 70%-79% of control by NRS and to 8%-9% by RAMBS. Curative cells for the W/Wv were not detectably reduced by NRS; they were reduced by RAMBS, but to only approximately 20%-30% of control. Thus, it appeared to a certain degree that RAMBS spared HSC with a high proliferative potential when compared with its effect on the entire CFU-S compartment.

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PubMed1984

Factors affecting the proliferation and differentiation of clonogenic hematopoietic stem cells in vitro.

The characteristics of hematopoietic factors modulating the growth of clonogenic pluripotent stem cells (PSC) in culture (i.e., CFU-GEMM) are examined. The chemical and biologic properties of "burst-promoting activity" (BPA) are compared with those of the lymphokine interleukin-3 (Il-3). The preponderance of the data available suggests that the active moiety of each of these growth factors may be chemically identical since both BPA and purified Il-3 are capable of supporting the growth of PSC in vitro. The effects of hemin on the growth of CFU-GEMM are also examined experimentally. The results show conclusively that, in the absence of exogenous (BPA), hemin is also capable of supporting the growth of CFU-GEMM in culture and to a level that is consistently higher than that of BPA alone. It is therefore suggested that hemin is capable of augmenting the growth of GEMM colonies in vitro in conjunction with BPA/Il-3. However, the in situ role of each of these "candidate" regulators of hemopoiesis remains largely unknown.

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PubMed1984

Specificity of hemin action in vivo at early stages of hematopoietic cell differentiation.

The effects of a single injection of hemin on murine marrow BFU-E and CFU-S were assessed to determine whether hemin is as effective in augmenting primitive (day 7) BFU-E levels in situ as it is in vitro and to assess hemin's action on transplantable pluripotent stem cells (CFU-S). The results show that hemin exerts a cell-specific enhancement of both BFU-E marrow levels and cell cycling within 6 h of its administration in vivo. No such effect on CFU-S was observed.

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PubMed1983

Further characterization of the hemin-induced enhancement of primitive erythroid progenitor cell growth in vitro.

We have previously demonstrated that hemin specifically enhances the in vitro plating efficiency of primitive murine erythroid progenitors (day 7 BFUE), whereas it does not appear to affect more mature progenitors (mature BFUE or CFUE). In this report, we further characterize the effects of hemin on marrow-derived day 7 BFUE growth in vitro. BFUE were enhanced by hemin in a dose-dependent manner and to a greater extent in methyl cellulose than in plasma clot cultures. That hemin might increase the rate of cell division was suggested by the greater size of colonies grown in its presence as well as their earlier appearance in culture. In contrast, the addition of hemin to marrow cell cultures did not appear to affect the survival rate of BFUE or their progeny. While significantly augmenting the frequency of BFUE, hemin had no consistent stimulatory effect on CFUGM. Lastly, hemin was equally capable of augmenting burst growth in adherent cell-depleted as in whole marrow cell preparations. These experiments suggest that hemin augments directly and in a cell-specific manner the proliferation and/or differentiation of primitive marrow erythroid progenitors in vitro.

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PubMed1982

An alternate method for determining the proliferative status of transplantable murine stem cells.

A simple method for determining the fraction of transplantable hematopoietic stem cells (CFUS) in the S-phase of cell cycle is described and evaluated. The method involves the administration of hydroxyurea to the lethally-irradiated assay animal concomitantly with the cell transplant. With this method, S-phase estimates are equivalent to those obtained with other, more traditional, methods. In addition, the method may prove advantageous in situations where the cell yield is too low for in vitro incubation with 3H-TdR or when ex vivo cell manipulations must be avoided.

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PubMed1982

Hemin enhances the in vitro growth of primitive erythroid progenitor cells.

Since exogenous hemin has been shown to exert a variety of stimulatory effects on erythroid cells, including the augmentation of hemoglobin synthesis, we determined its effect on early stages of erythroid development by employing clonal cells assays. The addition of hemin at a concentration of 2 X 10(-4) M to cultures of normal murine marrow substantially increased the observed number of primitive BFU-E, which was in contrast to its lack of an effect on more mature erythroid colony-forming cells. This cell-specific enhancement of primitive BFU-E resulted in marrow frequencies equivalent to or exceeding those reported in the presence of "burst-promoting activity." In the presence of hemin, the number of BFU-E was also observed to be linearly related to the number of cells plated at very low plating densities, and the cell titration curve was observed to extrapolate to the origin. The evidence suggests that hemin may be a primary growth regulator of early developmental stages of erythroid progenitor cells.

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PubMed1981

Thymocyte involvement in spleen colony formation by subpopulations of hematopoietic stem cells.

Murine marrow preparations depleted of stem cells by prior incubation with rabbit, anti-mouse serum show augmented spleen colony-forming ability when exposed to fresh thymocytes. A 2- to 4-fold increase in colonies was observed when marrow-thymocyte interaction occurred under either in vivo or in vitro conditions. Colony augmentation was shown to be independent of both the strain used and the age of the thymocyte donor. In our hands, approximately one-half of the marrow stem cells surviving an exposure to the antiserum appear responsive to thymocyte interaction.

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PubMed1981

Characterization of murine erythroid progenitors with high erythropoietin sensitivity in vitro.

The microplasma clot culture system was employed to study the characteristics of late murine erythroid progenitor cells. Erythroid cluster and colony-forming cells (CFUE) were compared with regard to erythropoietin sensitivity, cell-cycle activity, response to hypertransfusion-induced plethora, average cell size, temporal kinetics of in vitro cluster or colony formation, and relative frequency in murine bone marrow. Results indicate that erythroid cluster-forming cells represent a stage of differentiation which is further along the erythroid pathway than CFUE and are nearly 6-fold more sensitive to the hormone.

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PubMed1981

Immunological evidence for murine hematopoietic stem cell subpopulations differing in self-renewal capacity.

The present study provides evidence for a correlation between the brain-associated stem cell antigen and the self-renewal capacity of pluripotent hematopoietic stem cells (spleen colony-forming units). A minor subpopulation of spleen colony-forming units which does not express the antigen exhibited a 3- to 4-fold greater self-renewal capacity while proliferating in both bone marrow and spleen compared to stem cells which express the antigen. This finding supports the 'generation-age' hypothesis for stem cell differentiation; according to this hypothesis, hematopoietic cells derive from a population of young stem cells which lack the antigen, exhibit a high self-renewal capacity, and are quiescent in cell cycle.

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