scholarly journals Downregulation of tenascin expression by glucocorticoids in bone marrow stromal cells and in fibroblasts.

1993 ◽  
Vol 123 (4) ◽  
pp. 1037-1045 ◽  
Author(s):  
M Ekblom ◽  
R Fässler ◽  
B Tomasini-Johansson ◽  
K Nilsson ◽  
P Ekblom

Tenascin, a predominantly mesenchymal extracellular matrix (ECM) glycoprotein has a rather restricted tissue distribution, but until now factors that inhibit its expression have not been identified. Glucocorticoids are known to be beneficial for establishment of myelopoiesis in long-term bone marrow cultures. Tenascin was found to be expressed in the bone marrow, and glucocorticoids were found to affect bone marrow tenascin expression. Both tenascin mRNAs and the mRNA of another ECM protein, laminin B1 chain, were drastically downregulated by glucocorticoids during initiation of bone marrow cultures. However, in already established long-term cultures glucocorticoids did not affect laminin B1 chain mRNA levels although tenascin mRNAs continued to be downregulated. Studies with a stromal cell line (MC3T3-G2/PA6) and fibroblasts (3T3) suggested that glucocorticoids act directly on the stromal cells that produce tenascin. In 3T3 cells this downregulation occurred within 12 h of glucocorticoid-treatment, suggesting that glucocorticoids acted through cis regulatory elements of the tenascin gene. We suggest that glucocorticoids in part regulate hematopoiesis by modifying the ECM. Furthermore, downregulation of tenascin expression by glucocorticoids may in part explain the restricted tissue distribution of tenascin in other tissues.

Blood ◽  
1986 ◽  
Vol 68 (6) ◽  
pp. 1348-1354 ◽  
Author(s):  
A Johnson ◽  
K Dorshkind

Abstract Hemopoiesis in long-term bone marrow cultures (LTBMC) is dependent on adherent stromal cells that form an in vitro hemopoietic microenvironment. Myeloid bone marrow cultures (MBMC) are optimal for myelopoiesis, while lymphoid bone marrow cultures (LBMC) only support B lymphopoiesis. The experiments reported here have made a comparative analysis of the two cultures to determine whether the stromal cells that establish in vitro are restricted to the support of myelopoiesis or lymphopoiesis, respectively, and to examine how the different culture conditions affect stromal cell physiology. In order to facilitate this analysis, purified populations of MBMC and LBMC stroma were prepared by treating the LTBMC with the antibiotic mycophenolic acid; this results in the elimination of hemopoietic cells while retaining purified populations of functional stroma. Stromal cell cultures prepared and maintained under MBMC conditions secreted myeloid growth factors that stimulated the growth of granulocyte-macrophage colonies, while no such activity was detected from purified LBMC stromal cultures. However, this was not due to the inability of LBMC stroma to mediate this function. Transfer of LBMC stromal cultures to MBMC conditions resulted in an induction of myeloid growth factor secretion. When seeded under these conditions with stromal cell- depleted populations of hemopoietic cells, obtained by passing marrow through nylon wool columns, the LBMC stromal cells could support long- term myelopoiesis. Conversely, transfer of MBMC stroma to LBMC conditions resulted in a cessation of myeloid growth factor secretion; on seeding these cultures with nylon wool-passed marrow, B lymphopoiesis, but not myelopoiesis, initiated. These findings indicate that the stroma in the different LTBMC are not restricted in their hemopoietic support capacity but are sensitive to culture conditions in a manner that may affect the type of microenvironment formed.


Blood ◽  
1986 ◽  
Vol 68 (6) ◽  
pp. 1348-1354 ◽  
Author(s):  
A Johnson ◽  
K Dorshkind

Hemopoiesis in long-term bone marrow cultures (LTBMC) is dependent on adherent stromal cells that form an in vitro hemopoietic microenvironment. Myeloid bone marrow cultures (MBMC) are optimal for myelopoiesis, while lymphoid bone marrow cultures (LBMC) only support B lymphopoiesis. The experiments reported here have made a comparative analysis of the two cultures to determine whether the stromal cells that establish in vitro are restricted to the support of myelopoiesis or lymphopoiesis, respectively, and to examine how the different culture conditions affect stromal cell physiology. In order to facilitate this analysis, purified populations of MBMC and LBMC stroma were prepared by treating the LTBMC with the antibiotic mycophenolic acid; this results in the elimination of hemopoietic cells while retaining purified populations of functional stroma. Stromal cell cultures prepared and maintained under MBMC conditions secreted myeloid growth factors that stimulated the growth of granulocyte-macrophage colonies, while no such activity was detected from purified LBMC stromal cultures. However, this was not due to the inability of LBMC stroma to mediate this function. Transfer of LBMC stromal cultures to MBMC conditions resulted in an induction of myeloid growth factor secretion. When seeded under these conditions with stromal cell- depleted populations of hemopoietic cells, obtained by passing marrow through nylon wool columns, the LBMC stromal cells could support long- term myelopoiesis. Conversely, transfer of MBMC stroma to LBMC conditions resulted in a cessation of myeloid growth factor secretion; on seeding these cultures with nylon wool-passed marrow, B lymphopoiesis, but not myelopoiesis, initiated. These findings indicate that the stroma in the different LTBMC are not restricted in their hemopoietic support capacity but are sensitive to culture conditions in a manner that may affect the type of microenvironment formed.


Blood ◽  
1984 ◽  
Vol 64 (2) ◽  
pp. 516-525 ◽  
Author(s):  
RJ Gualtieri ◽  
RK Shadduck ◽  
DG Baker ◽  
PJ Quesenberry

The nature of hematopoietic regulatory factors elaborated by the adherent (stromal) cells of long-term murine bone marrow cultures and the effect of in vitro stromal irradiation (XRT) on the production of these factors was investigated. Using an in situ stromal assay employing a double layer of semisolid agar, it was possible to demonstrate stromal elaboration of at least two colony-stimulating activities, ie, granulocyte/macrophage colony-stimulating activity (G/M- CSA) and megakaryocyte colony-stimulating activity (Meg-CSA). Exposure of the stroma to XRT resulted in dose-dependent elevations of both activities that correlated inversely with total myeloid cell mass as determined by concurrent reductions in total supernatant cell recoveries from irradiated cultures. Mixture experiments that combined control and irradiated stroma revealed that the hematopoietically active control stroma could block detection of XRT-related G/M-CSA elevations. These data implicate a local negative feedback mechanism in the regulation of hematopoiesis. Antiserum directed against purified L cell colony-stimulating factor (CSF) reduced granulocyte/macrophage colony formation in the target layer but did not effect the increased Meg-CSA. While a radioimmunoassay for L-cell type CSF was unable to detect significant differences in concentrated media from control and irradiated cultures, bioassays of these media revealed XRT-related G/M- CSA elevations. These results indicate that the G/M-CSA elaborated in these cultures is immunologically distinct from the Meg-CSA produced, and although distinct from L cell CSF, the G/M-CSA is crossreactive with the L cell CSF antiserum. Morphologic, histochemical, and factor VII antigen immunofluorescent studies were performed on the stromal cell population responsible for production of these stimulatory activities. In addition to “fat” cells, the stromal cells remaining after XRT were composed of two predominant cell populations. These included a major population of acid phosphatase and nonspecific esterase-positive macrophage-like cells and a minor population of factor VII antigen negative epithelioid cells.


Blood ◽  
1992 ◽  
Vol 79 (12) ◽  
pp. 3168-3178 ◽  
Author(s):  
EL Kittler ◽  
H McGrath ◽  
D Temeles ◽  
RB Crittenden ◽  
VK Kister ◽  
...  

Abstract The “stromal” or adherent cells of long-term murine Dexter explant bone marrow cultures provide the best in vitro model of the bone marrow microenvironment. Colony-stimulating factor-1 (CSF-1) is produced constitutively by these cells and is easily detected, but most investigators have not found constitutive production of the other hemolymphopoietic cytokines. We have previously reported the detection of granulocyte-macrophage-CSF (GM-CSF) in murine stromal cultures and its induction by the lectin Pokeweed mitogen. The present studies analyzing stromal cytokine messenger RNA (mRNA) production by standard Northern blot analysis show constitutive production of mRNAs for CSF-1, GM-CSF, granulocyte-CSF (G-CSF), c-kit ligand (KL), and interleukin-6 (IL-6), but not IL-3, IL-4, or IL-5 by 3-week irradiated or nonirradiated murine Dexter stromal cells. Exposure of stromal cells to Pokeweed mitogen or IL-1 16 hours before RNA harvest induces the messages for GM-CSF, G-CSF, KL, and IL-6, but not IL-3, IL-4, IL-5, or CSF-1. Polymerase chain reaction amplification of cDNA made with reverse transcriptase from stromal RNA using two separate sets of IL-3- specific primers shows the presence of IL-3 message in irradiated stromal cells, which is only detectable with this more sensitive technique. The factor-dependent cell lines FDC-P1 and 32D are supported by the stromal cells without the addition of exogenous growth factors, demonstrating a cytokine activity in these cultures that is inhibited by the addition of anti-IL-3 or anti-GM-CSF antibodies. These data indicate that murine Dexter stromal cells constitutively produce CSF-1, GM-CSF, G-CSF, IL-6, KL, and IL-3. This growth factor production could explain the support of granulocyte, macrophage, and megakaryocyte production and stem cell maintenance in Dexter-type long-term murine bone marrow cultures.


Blood ◽  
1994 ◽  
Vol 84 (12) ◽  
pp. 4116-4124 ◽  
Author(s):  
L Croisille ◽  
I Auffray ◽  
A Katz ◽  
B Izac ◽  
W Vainchenker ◽  
...  

Very primitive human hematopoietic progenitor cells are identified indirectly by their ability to give rise to clonogenic progenitors in the presence of either human or murine stromal cells. These long-term culture-initiating cell (LTC-IC) assays are usually performed in the presence of hydrocortisone based on the initial observation that hydrocortisone was required for prolonged hematopoiesis in standard long-term bone marrow cultures. In this report, we investigated the role of hydrocortisone in LTC-IC assays initiated with CD34++/CD38- cells seeded onto either human bone marrow LTC-derived adherent cells or a murine marrow-derived stromal cell line, MS-5. It was found that weekly addition of hydrocortisone to the cultures reduced the frequency of LTC-IC (from 1/5 to 1/20) calculated from limiting dilution experiments and also reduced fivefold to 10-fold the number of their progeny clonogenic cells detected after 4 to 5 weeks. In contrast, the frequency and differentiative potential of CD34++/CD38- grown in the presence of human marrow feeders was unaltered by the addition of glucocorticoids. Data are consistent with the hypothesis that hydrocortisone inhibited LTC-IC differentiation by downregulating the expression of a synergistic factor produced by MS-5 cells. (1) In the absence of hydrocortisone, the number of clonogenic progenitors generated by LTC-IC was much higher in cultures seeded on MS-5 than in cultures seeded on human marrow adherent cells, which was also true when cytokines were added to the cocultures. However, based on the phenotype of the colonies, progenitors produced in MS-5 cocultures were more mature than those generated on human marrow adherent cells. (2) Hydrocortisone counteracted the stimulatory effect of recombinant human cytokines (interleukin-3, interleukin-6, and steel factor) in assays performed on MS-5 but not on human marrow feeders. (3) Hydrocortisone led to a 50% decrease in the numbers of colony-forming units- granulocyte-macrophage found in methycellulose colony assays of CD34++/CD38- cells performed in the presence of MS-5 cells. Taken together, our results indicate that hydrocortisone acts differently on a murine stromal cell line and on marrow-derived human stromal cells and may suppress the expression by MS-5 cells of an activity selectively promoting amplification of clonogenic cells derived from primitive LTC-IC.


Blood ◽  
1983 ◽  
Vol 61 (3) ◽  
pp. 540-547 ◽  
Author(s):  
KS Zuckerman ◽  
MS Wicha

Abstract We have studied the deposition of extracellular matrix proteins in the adherent stroma of long-term murine bone marrow cultures. Stable hematopoiesis was maintained for greater than 12 wk. At selected intervals, culture dishes were sacrificed by removing all nonadherent cells and air drying the dishes. The adherent stromal layer was analyzed for the presence of intracellular and extracellular collagen, fibronectin, and laminin using double immunofluorescent staining with specific antisera against these matrix components. In cultures examined during the first 2 wk, large numbers of stromal cells contained collagen, fibronectin, and laminin. Over the next 2 wk, an extensive extracellular network of fibronectin, laminin, and collagen was deposited on the dishes, which persisted throughout the life of the cultures. In contrast to a previous report, we detected substantial numbers of endothelial cells by means of immunofluorescent staining of stromal cells with antisera to type IV collagen, laminin, and factor VIII antigen. Although deposition of these extracellular matrix proteins coincides with onset of active hematopoietic cell production, the relative roles of the stromal cells and the extracellular matrix in supporting hematopoiesis in murine bone marrow cell cultures remain to be determined.


Blood ◽  
1983 ◽  
Vol 61 (3) ◽  
pp. 540-547 ◽  
Author(s):  
KS Zuckerman ◽  
MS Wicha

We have studied the deposition of extracellular matrix proteins in the adherent stroma of long-term murine bone marrow cultures. Stable hematopoiesis was maintained for greater than 12 wk. At selected intervals, culture dishes were sacrificed by removing all nonadherent cells and air drying the dishes. The adherent stromal layer was analyzed for the presence of intracellular and extracellular collagen, fibronectin, and laminin using double immunofluorescent staining with specific antisera against these matrix components. In cultures examined during the first 2 wk, large numbers of stromal cells contained collagen, fibronectin, and laminin. Over the next 2 wk, an extensive extracellular network of fibronectin, laminin, and collagen was deposited on the dishes, which persisted throughout the life of the cultures. In contrast to a previous report, we detected substantial numbers of endothelial cells by means of immunofluorescent staining of stromal cells with antisera to type IV collagen, laminin, and factor VIII antigen. Although deposition of these extracellular matrix proteins coincides with onset of active hematopoietic cell production, the relative roles of the stromal cells and the extracellular matrix in supporting hematopoiesis in murine bone marrow cell cultures remain to be determined.


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