Epithelial cells are the major source of biologically active granulocyte macrophage colony-stimulating factor in human endometrium

Abstract

Granulocyte macrophage colony-stimulating factor (GM-CSF) has emerged as an important growth factor for trophoblast and other placental cells, leading to improved placental functioning and fetal survival. Recent observations have indicated that GM-CSF is synthesized by epithelial cells in the murine pregnant and non-pregnant uterus. In this study, the production of GM-CSF by cells derived from human endometrium is assessed using a sensitive bioassay and specific neutralization of the cytokine bioactivity with a monoclonal antibody to GM-CSF. Originally, GM-CSF was assayed in the culture supernatants of explant cultures of human endometria. Concentrations of GM-CSF up to 4440 pg/ml were detected. Subsequently, enriched epithelial cell cultures were prepared from glands isolated from human endometrium. The purity of epithelial cultures was demonstrated by the expression of cytokeratin, a weak immunoreactivity for vimentin and a lack of immunoreactivity for leukocyte common antigen, CD68, a macrophage-specific protein and endothelial marker (factor VIII-related antigens). Detected concentrations of GM-CSF were as high as 18,800 pg/ml. Furthermore, pure epithelial cells of a neoplastic endometrial cell line ECC1 secreted GM-CSF, confirming the ability of endometrial epithelial cells to secrete this cytokine. The immunostaining of dated endometria from proliferative and secretory phases showed primarily that epithelial cells, and to a lesser extent stromal cells, exhibited immunoreactivity for GM-CSF. A Western blot analysis, performed to validate the immunohistochemical data, confirmed the presence of an immunoreactive gene product for GM-CSF in human endometrium throughout the menstrual cycle. These findings indicate that human endometrium synthesizes GM-CSF and that epithelial cells are a major contributor to its production.

Differential regulation of neutrophil chemotaxis to IL‐8 and fMLP by GM‐CSF: lack of direct effect of oestradiol

“…10 The concentration of GM-CSF used to treat neutrophils in our experiments (4 ng/ml) is well within this range. It is possible that one of the many actions of GM-CSF on neutrophils could be to down-regulate responses when they are no longer necessary to the role of the cell.…”

“…9 GM-CSF is produced by the tissues of the female reproductive tract 10 and its synthesis is now known to be hormonally regulated, at least in rodents. 11 Female reproductive tract tissues that produce IL-8 are also reported to produce GM-CSF.…”

Cyclical variation of leucocyte profile in healthy females: a comparison with males

“…Other studies have confirmed the presence of an immunoreactive gene product for GM-CSF in human endometrium throughout the menstrual cycle. These findings indicate that human endometrium synthesizes GM-CSF and that epithelial cells are a major contributor to its production 23 .…”

Developmental potential of isolated blastomeres from early mouse embryos in the presence and absence of LIF and GM-CSF

“…LIF and GM-CSF are expressed and secreted by the female reproductive tract of mammals and affect the development of pre-implantation embryos [17][18][19][20]. Several cell lineages in the reproductive tract and gestational tissues synthesize LIF and GM-CSF under direction by ovarian steroid hormones [18].…”

“…Several cell lineages in the reproductive tract and gestational tissues synthesize LIF and GM-CSF under direction by ovarian steroid hormones [18].…”