Epithelial cell protein milk fat globule-epidermal growth factor 8 and human chorionic gonadotropin regulate stromal cell apoptosis in the human endometrium.

To study the regulation of apoptosis in human endometrial cells. The specific aims were to determine whether milk fat globule-epidermal growth factor 8 (MFG-E8), a novel endometrial epithelial protein, modulates caspase activation and DNA fragmentation; and to examine whether hCG, an early embryonic product, regulates Bax and Bcl-2 equilibrium, as well as MFG-E8 expression. Primary cultures of human endometrial epithelial cells (EECs) and endometrial stromal cells (ESCs). Academic center. Ovulatory women aged 21-30 years. Treatment with MFG-E8 and hCG. Apoptotic activity was quantified using a luciferase assay. Deoxyribonucleic acid fragmentation was detected by TUNEL assay. Bax, Bcl-2, and MFG-E8 messenger RNA expression levels were determined by quantitative reverse transcription-polymerase chain reaction. Immunocytochemistry was used to establish cell purity and presence of MFG-E8 and hCG-R (receptor) proteins. Endometrial epithelial cells were cytokeratin(+), vimentin(-), MFG-E8(+), and hCG-R(+), whereas ESC were vimentin(+), cytokeratin(-), MFG-E8(-), and hCG-R(+). Treatment of ESC with MFG-E8 resulted in a 13-fold increase in caspase activity and a 30-fold increase in TUNEL. On the other hand, hCG decreased messenger RNA expression of Bax in ESC. Milk fat globule-epidermal growth factor 8 has proapoptotic activity, suggesting participation in endometrial remodeling via an epithelial-stromal cell paracrine effect. Conversely, pregnancy levels of hCG has opposite effects on stromal cells.

Riggs RM ，Bocca S ，Anderson S ，Franchi A ，Rhavi BS ，Oehninger S ... -  《-》

Expression of milk fat globule EGF-factor 8 (MFG-E8) mRNA and protein in the human endometrium and its regulation by prolactin.

Franchi A ，Bocca S ，Anderson S ，Riggs R ，Oehninger S ... -  《-》

Tumor necrosis factor α up-regulates endometrial milk fat globule-epidermal growth factor 8 protein production via nuclear factor κB activation, resulting in cell migration of epithelial cells.

To explore the role of tumor necrosis factor (TNF) α, an early embryonic product, on endometrial epithelial cell migration and endometrial milk fat globule-epidermal growth factor 8 protein (MFG-E8) production. In vitro study. Academic center. Ishikawa cells, used as surrogates for human epithelial cells, were treated with and without TNF-α. Effect of TNF-α on intracellular MFG-E8 protein was evaluated with the use of ELISA, Western blot, and subcellular fractionation. Specific inhibitors were used to study TNF-α mechanism of action. Effect of TNF-α on cell migration was studied with the use of a wound healing assay and reorganization of E-cadherin. TNF-α induced: 1) significant up-regulation of MFG-E8 intracellular protein, which was attenuated by pretreatment with a specific inhibitor of nuclear factor κB; 2) increased transcription of MFG-E8 and other proinflammatory factors, such as interleukins 6 and 8, which were suppressed by cotreatment with hCG; and 3) significant cell migration with E-cadherin remodeling, changes associated with subcellular MFG-E8 relocalization. TNF-α up-regulates endometrial epithelial cell migration and MFG-E8 production, which are critical steps required for the endometrial changes during menstrual cycle as well as during embryonic attachment and invasion.

Yu L ，Anderson S ，Oehninger S ，Bocca S ... -  《-》

Milk fat globule epidermal growth factor 8 (MFG-E8): a novel protein in the mammalian endometrium with putative roles in implantation and placentation.

MFG-E8 is a novel endometrial protein with conserved functions in tissue remodeling and angiogenesis in non-uterine tissues. Our aims were: 1. To examine the presence of MFG-E8 protein in the human endometrium during the window of implantation, in human endometrial cell lines, in human placental tissue at different gestational ages, and in murine implantation sites during early gestation; and 2. To study the regulation of MFG-E8 mRNA expression in mice implantation sites. MFG-E8 protein and its receptor integrin αvβ3 were detected by immunostaining in human endometrial biopsies obtained from normal volunteers, in human endometrial cell lines (epithelial: Ishikawa and HEC-1A, stromal: HESC, and endothelial: HEEC), in human products of conception from all trimesters of gestation, and in murine implantation and inter-implantation sites dissected on days 5 and 8 post-coitus. MFG-E8 gene expression was assessed by RT-PCR. Immunohistochemical determination of MFG-E8 in endometrium and products of conception as well as relative MFG-E8 mRNA expression in mice implantation sites. MFG-E8 protein was present almost exclusively in the epithelial compartment of human endometrium. It was also expressed in the cytotrophoblasts and syncytiotrophoblasts outlining chorionic villi of the human placenta at all trimesters of gestation, and in murine implantation sites. MFG-E8 mRNA was significantly up-regulated in murine implantation sites and with increased gestational age. MFG-E8 expression in the endometrial epithelium as well as in chorionic villi suggests its possible role in endometrial reorganization during the receptive phase and in events related to normal pregnancy in mammals.

Bocca SM ，Anderson S ，Amaker B ，Swanson RJ ，Franchi A ，Lattanzio F ，Oehninger S ... -  《-》

Role for the endometrial epithelial protein MFG-E8 and its receptor integrin αvβ3 in human implantation: results of an in vitro trophoblast attachment study using established human cell lines.

To investigate the role of MFG-E8 and its receptor integrin αvβ3 in the attachment of trophoblast cells to the endometrial epithelium. Experimental in vitro study. Academic center. None. By using a well-differentiated endometrial adenocarcinoma cell line (Ishikawa cells) and choriocarcinoma human trophoblast cells (Jar cells), an in vitro assay mimicking human implantation was established. To investigate the impact of blocking MFG-E8 and integrin αvβ3, we pretreated the cell lines with antibodies against those proteins at different concentrations before the attachment assay. Attachment rate of Jar spheroids to the epithelial cell monolayer. Pretreatment of Ishikawa cells with anti-MFG-E8 antibody caused a dose-dependent and significant inhibition of attachment. On the other hand, pretreatment of Jar spheroids did not result in a significant effect on the attachment rate. Pretreatment of Ishikawa cells as well as Jar spheroids with anti-integrin αvβ3 antibodies resulted in a dose-dependent, significant inhibition of attachment. This study showed that blocking MFG-E8 and its receptor integrin αvβ3 in Ishikawa cells diminishes Jar spheroid attachment. Moreover, blocking integrin αvβ3 in the trophoblastic cells also diminished their attachment to the Ishikawa monolayer.

Schmitz C ，Yu L ，Bocca S ，Anderson S ，Cunha-Filho JS ，Rhavi BS ，Oehninger S ... -  《-》