Down-regulation of oxytocin-induced cyclooxygenase-2 and prostaglandin F synthase expression by interferon-tau in bovine endometrial cells. (1/1380)

Oxytocin (OT) is responsible for the episodic release of luteolytic prostaglandin (PG) F2alpha from the uterus in ruminants. The attenuation of OT-stimulated uterine PGF2alpha secretion by interferon-tau (IFN-tau) is essential for prevention of luteolysis during pregnancy in cows. To better understand the mechanisms involved, the effect of recombinant bovine IFN-tau (rbIFN-tau) on OT-induced PG production and cyclooxygenase-2 (COX-2) and PGF synthase (PGFS) expression in cultured endometrial epithelial cells was investigated. Cells were obtained from cows at Days 1-3 of the estrous cycle and cultured to confluence in RPMI medium supplemented with 5% steroid-free fetal calf serum. The cells were then incubated in the presence or absence of either 100 ng/ml OT or OT+100 ng/ml rbIFN-tau for 3, 6, 12, and 24 h. OT significantly increased PGF2alpha and PGE2 secretion at all time points (p < 0.01), while rbIFN-tau inhibited the OT-induced PG production and reduced OT receptor binding in a time-dependent manner. OT increased the steady-state level of COX-2 mRNA, measured by Northern blot, which was maximal at 3 h (9-fold increase) and then decreased with time (p < 0.01). OT also caused an increase in COX-2 protein, which peaked at 12 h (11-fold increase), as measured by Western blot. Addition of rbIFN-tau suppressed the induction of COX-2 mRNA (89%, p < 0.01) and COX-2 protein (50%, p < 0.01) by OT. OT also increased PGFS mRNA, and this stimulation was attenuated by rbIFN-tau (p < 0.01). To ensure that the decrease in COX-2 was not solely due to down-regulation of the OT receptor, cells were stimulated with a phorbol ester (phorbol 12-myristate 13-acetate; PMA) in the presence and absence of rbIFN-tau. The results showed that rbIFN-tau also decreased PMA-stimulated PG production and COX-2 protein. It can be concluded that rbIFN-tau inhibition of OT-stimulated PG production is due to down-regulation of OT receptor, COX-2, and PGFS.  (+info)

Tissue factor pathway inhibitor-2 is a novel mitogen for vascular smooth muscle cells. (2/1380)

A mitogen for growth-arrested cultured bovine aortic smooth muscle cells was purified to homogeneity from the supernatant of cultured human umbilical vein endothelial cells by heparin affinity chromatography and reverse-phase high performance liquid chromatography. This mitogen was revealed to be tissue factor pathway inhibitor-2 (TFPI-2), which is a Kunitz-type serine protease inhibitor. TFPI-2 was expressed in baby hamster kidney cells using a mammalian expression vector. Recombinant TFPI-2 (rTFPI-2) stimulated DNA synthesis and cell proliferation in a dose-dependent manner (1-500 nM). rTFPI-2 activated mitogen-activated protein kinase (MAPK) activity and stimulated early proto-oncogene c-fos mRNA expression in smooth muscle cells. MAPK, c-fos expression and the mitogenic activity were inhibited by a specific inhibitor of MAPK kinase, PD098059. Thus, the mitogenic function of rTFPI-2 is considered to be mediated through MAPK pathway. TFPI has been reported to exhibit antiproliferative action after vascular smooth muscle injury in addition to the ability to inhibit activation of the extrinsic coagulation cascade. However, structurally similar TFPI-2 was found to have a mitogenic activity for the smooth muscle cell.  (+info)

Modulation of the baboon (Papio anubis) uterine endometrium by chorionic gonadotrophin during the period of uterine receptivity. (3/1380)

This study was undertaken to determine the modulation of uterine function by chorionic gonadotrophin (CG) in a nonhuman primate. Infusion of recombinant human CG (hCG) between days 6 and 10 post ovulation initiated the endoreplication of the uterine surface epithelium to form distinct epithelial plaques. These plaque cells stained intensely for cytokeratin and the proliferating cell nuclear antigen. The stromal fibroblasts below the epithelial plaques stained positively for alpha-smooth muscle actin (alphaSMA). Expression of alphaSMA is associated with the initiation of decidualization in the baboon endometrium. Synthesis of the glandular secretory protein glycodelin, as assessed by Western blot analysis, was markedly up-regulated by hCG, and this increase was confirmed by immunocytochemistry, Northern blot analysis, and reverse transcriptase-PCR. To determine whether hCG directly modulated these uterine responses, we treated ovariectomized baboons sequentially with estradiol and progesterone to mimic the hormonal profile of the normal menstrual cycle. Infusion of hCG into the oviduct of steroid-hormone-treated ovariectomized baboons induced the expression of alphaSMA in the stromal cells and glycodelin in the glandular epithelium. The epithelial plaque reaction, however, was not readily evident. These studies demonstrate a physiological effect of CG on the uterine endometrium in vivo and suggest that the primate blastocyst signal, like the blastocyst signals of other species, modulates the uterine environment prior to implantation.  (+info)

Pregnancy detection and the effects of age, body weight, and previous reproductive performance on pregnancy status and weaning rates of farmed fallow deer (Dama dama). (4/1380)

Fallow does (n = 502) of different ages (mature, 2-yr-old, and yearling) were maintained with bucks for a 60-d breeding season to determine whether previous reproductive performance and changes in BW affect doe pregnancy rates and to compare the effectiveness of ultrasonography and serum pregnancy-specific protein B (PSPB) for the detection of pregnancy in fallow does. Ultrasonography was performed, blood samples collected, and BW recorded at buck removal (d 0) and at 30 and 90 d after buck removal. Lactational status (lactating = WET; nonlactating = DRY) were determined from farm records taken at weaning prior to each breeding season (autumn 1990 through autumn 1994). Ultrasonography and PSPB for determining pregnancy were in agreement 93% of the time. Overall pregnancy rates did not differ (P>.10) relative to age of the doe; the combined pregnancy rate was 92%. We also determined that 82.9% of does conceived early in the breeding season and that the incidence of embryonal-fetal mortality during the first 90 d after buck removal was 2.8%. In general, mature and 2-yr-old DRY does were heavier and had lower pregnancy rates than WET does. The overall weaning rate for all does was 77.9%. Loss in the number of fawns from pregnancy detection to weaning was equivalent to 14.8% for mature does, 24.7% for 2 yr old does, and 42.5% for yearling does. These data indicate that even though pregnancy rates were relatively high, further study is needed to determine the causes associated with subsequent fawn losses, particularly among yearling does. As a production tool, lactational WET/ DRY status testing was found to be an acceptable means for determining the reproductive potential of individual does within the herd. In addition, serum PSPB may be used in place of ultrasonography for pregnancy diagnosis in fallow deer as early as d 30 after buck removal.  (+info)

Increased expression of regeneration and tolerance factor in individuals with human immunodeficiency virus infection. (5/1380)

Regeneration and tolerance factor (RTF) plays a pivotal role in successful pregnancy outcome and has potent immunomodulating properties. During pregnancy, it is abundantly expressed in the placenta and on peripheral B lymphocytes. Several lines of evidence suggest that both successful pregnancy outcome and progression from human immunodeficiency virus (HIV) infection to AIDS are associated with a Th2-type response. As a result, we hypothesized that the cellular expression of RTF may also be increased during infection with HIV. Using flow cytometric analysis, we showed a significantly (P < 0.01) increased expression of RTF on CD3(+) cells obtained from individuals with HIV over that for individuals without HIV. On average, 32.1% of the CD3(+) cells from individuals with HIV expressed high levels of RTF. In contrast, an average of only 6.7% of the CD3(+) cells from individuals without HIV expressed high levels of RTF. Similar results were obtained when CD19(+) cells from individuals with (mean, 44.1%) and without (mean, 25.8%) HIV were evaluated. Linear regression analysis suggested that high levels of RTF expression by CD3(+) cells correlated better with viral load (r value, 0.46) than with absolute CD4 count (r value, 0.09). While additional experiments are necessary to delineate the precise immunologic role of RTF, our current data suggest that RTF expression during HIV infection may be a useful marker of immune activation.  (+info)

Chemotactic, mitogenic, and angiogenic actions of UTP on vascular endothelial cells. (6/1380)

Endothelial cells express receptors for ATP and UTP, and both UTP and ATP elicit endothelial release of vasoactive compounds such as prostacyclin and nitric oxide; however, the distinction between purine and pyrimidine nucleotide signaling is not known. We hypothesized that UTP plays a more important role in endothelial mitogenesis and chemotaxis than does ATP and that UTP is angiogenic. In cultured endothelial cells from guinea pig cardiac vasculature (CEC), both UTP and vascular endothelial growth factor (VEGF) were significant mitogenic and chemotactic factors; in contrast, ATP demonstrated no significant chemotaxis in CEC. In chick chorioallantoic membranes (CAM), UTP and VEGF treatments produced statistically significant increases in CAM vascularity compared with controls. These findings are the first evidence of chemotactic or angiogenic effects of pyrimidines; they suggest a role for pyrimidine nucleotides that is distinct from those assumed by purine nucleotides and provide for the possibility that UTP serves as an extracellular signal for processes such as endothelial repair and angiogenesis.  (+info)

Signal transduction and biological function of placenta growth factor in primary human trophoblast. (7/1380)

Placenta growth factor (PlGF), a member of the vascular endothelial growth factor family of angiogenic factors, is prominently expressed by trophoblast. In addition to its role as a paracrine angiogenic factor within the placenta and endometrium, presence of its receptor, Flt-1, on trophoblast suggests that PlGF also may have an autocrine role(s) in regulating trophoblast function. To elucidate its role in trophoblast, we examined the signal transduction and functional responses of primary human trophoblast to PlGF. Exogenous PlGF induced specific activation of the stress-activated protein kinase (SAPK) pathways, c-Jun-N terminal kinase (JNK) and p38 kinase, in primary term trophoblast with little to no induction of the extracellular signal regulated kinase (ERK-1 and -2) pathways. In contrast, PlGF induced significant ERK-1 and -2 activity in human umbilical vein endothelial cells but did not induce JNK or p38 activity. PlGF-induced activation of the SAPK signaling pathways protected trophoblast from growth factor withdrawal-induced apoptosis, but it did not protect trophoblast from apoptosis induced by the pro-inflammatory cytokines, interferon gamma and tumor necrosis factor alpha. These results provide the first direct evidence of a biochemical and functional role for PlGF/Flt-1 in normal trophoblast and suggest that aberrant PlGF expression during pregnancy may impact upon trophoblast function as well as vascularity within the placental bed.  (+info)

Are human placental bed giant cells merely aggregates of small mononuclear trophoblast cells? An ultrastructural and immunocytochemical study. (8/1380)

The ultrastructure of placental bed giant cells in early human pregnancies of 7-12 weeks gestational age is described. Their nature and function was further characterized by confocal immunofluorescence microscopy of paraffin sections labelled for cytokeratin, gap junction connexins (CX) 32 or 43, and placental hormones, alpha-human chorionic gonadotrophin (alpha-HCG) and human placental lactogen (HPL). Placental bed giant cells were observed with two phenotypes; as single large trophoblast cells containing one or more nuclear profiles in a voluminous cytoplasm, and as cell aggregates comprising mononuclear trophoblast cells in close apposition separated by narrow intercellular spaces. Cells within the aggregates are attached to one another by desmosomes, and also possess gap junctions as shown by immunolabelling for CX32 and CX43. By contrast, gap junctions were absent in the true multinucleated giant cells. Organelles present within the cytoplasm of the giant cells and their immunoreactivity for HPL and alpha-HCG suggest protein synthesis.  (+info)