Catecholamines modulate epidermal growth factor-induced prostaglandin E2 production in amnion-like (WISH) cells by means of a cyclic adenosine monophosphate-dependent pathway

Physiological apoptotic agents have different effects upon human amnion epithelial and mesenchymal cells

Foetal membrane rupture is thought to follow from gene-controlled tissue remodelling and apoptosis. We reported previously that staurosporine, cycloheximide, actinomycin D, as well as more physiological apoptotic agents (lactosylceramide, 15d-PGJ(2)) increase prostaglandin release in parallel with induction of apoptosis in WISH and amnion epithelial cells. Also, inhibition of prostaglandin release by cyclooxygenase inhibitors or PKA activators is accompanied by a parallel decrease in apoptosis. We hypothesize that amnion prostaglandin metabolism is linked with apoptosis in amnion epithelial cells and thus to membrane rupture. Amnion mesenchymal cells are also critical for membrane integrity. Their susceptibility to apoptotic agents is unknown and is the subject of this report. In amnion epithelial cells, lactosylceramide (125 microM) induced 6.5-fold, 20-fold increases in PGE(2) and NMP production (apoptosis), respectively. Conversely, in mesenchymal cells, lactosylceramide doses up to 200 microM had no effect on PGE(2) or NMP release. In both cell types, incubation with 15d-PGJ(2) (5-100 microM) demonstrated dose and time dependent increases in PGE(2) and NMP. PKA activators inhibited 15d-PGJ(2) induced PGE(2) release and apoptotis in epithelial cells, but not in mesenchymal cells, however. Major amnion cell types have different sensitivities to physiological apoptotic agents. Prostaglandin release occurs coincident with apoptosis in both amnion epithelial and mesenchymal cells.

Control of in vitro prostaglandin F2 alpha and E2 synthesis by caruncular and allantochorionic tissues from cows that calved normally and those with retained fetal membranes

High concentrations of PGF2 alpha and PGE2 are produced by the uterus during the early postpartum period in cows and may play an important role in both placental separation and uterine involution. In the present study, we have examined the hormonal and intracellular control mechanisms involved in PGF2 alpha and PGE2 secretion by caruncular and allantochorionic tissue in vitro. Tissue explants, obtained about 6 hr postpartum from cows that delivered normally (NFM, n = 10) or cows with retained fetal membranes (RFM, n = 4), were incubated for 6 hr and PGF2 alpha and PGE2 concentrations in the medium were determined by radioimmunoassay. Addition of oxytocin (100 microU/ml), platelet activating factor (PAF, 100 ng/ml) and epidermal growth factor (EGF, 100 ng/ml) had no effect on secretion of PGF2 alpha from the caruncle, but oxytocin and PAF did stimulate PGE2. There was no difference between groups of cows. All three substances stimulated PGF2 alpha from the allantochorion of NFM, but not RFM, cows and stimulated PGE2 secretion from the allantochorion of both groups of cows. Incubation of the tissues with cholera toxin (100 ng/ml), dibutyryl cyclic adenosine 3',5'-monophosphate (dibutyryl cAMP, 1 mM), calcium ionophore A23187 (5 microM) or phorbol ester 12-myristate-13 acetate (PMA, 100 nM) showed that PGF2 alpha secretion is essentially via the calcium-protein kinase C effector pathway. However, calcium-protein kinase C and cAMP second messenger systems appear to be involved in the secretion of PGE2. Prostaglandin secretion was sensitive to cycloheximide in both caruncular and allantochorionic tissues, suggesting that protein synthesis may be involved. In conclusion, these data show that in vitro PGF2 alpha secretion can be modulated by the agonists used only in allantochorion and is essentially via the calcium-protein kinase C effector pathway. PGE2 secretion can be modified in both caruncular and allantochorion tissues and involves both inositol triphosphate-diacylglycerol and cAMP second messenger systems.

Effect of epidermal growth factor, transforming growth factor alpha and nerve growth factor on gastric mucosal integrity and microcirculation in the rat

In the present study we have compared the effects of the peptide growth factors epidermal growth factor (EGF), transforming growth factor alpha (TGF alpha) and nerve growth factor (NGF) on gastric mucosal integrity and mucosal blood flow in the rat. Mucosal damage was assessed 30 min after intraluminal instillation of 40% (w/v) ethanol (EtOH). EtOH treatment resulted in an increase in mucosal damage when compared to saline treated control animals. Administration of each growth factor either by tail vein (i.v.; 0.2-1 nmol/kg) or via the left gastric artery (i.a.; 0.05-0.2 nmol/kg) resulted in a significant reduction in the extent of mucosal damage. The growth factors reduced EtOH-mediated damage in an equipotent manner. The reduction in the area hemorrhagic damage ranged from -25 to -35% from EtOH alone when the factors were administered i.a. and from -75 to -85% when delivered i.v. Gastric mucosal blood flow as assessed by laser Doppler flowmetry (LDF) was increased in a dose-dependent and equipotent manner by EGF and TGF alpha administered either by the i.v. or i.a. route. LDF changes were greater when EGF or TGF alpha were delivered via the i.a. route. NGF did not significantly increase blood flow regardless of the dose or route of delivery. beta-Adrenoceptor blockade with propranolol (0.75 mg/kg i.v.) abolished the increase in LDF in response to EGF or TGF alpha but did not affect the ability of these growth factors to reduce EtOH-mediated damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Protein kinase A interactions with prostaglandin biosynthesis at the chorio-decidual interface

Activation of the enzyme adenylate cyclase or treatment with dibutyryl cyclic AMP (dbcAMP) stimulates prostaglandin biosynthesis in vitro and in vivo. Prior activation of adenylate cyclase has been shown to inhibit the stimulation of amnion cell prostaglandin E2 (PGE2) biosynthesis by substances such as epidermal growth factor (EGF) and phorbol 12-myristate 13-acetate (PMA). Little is known, however, concerning the effects of activation of the adenylate cyclase system on basal and stimulated prostaglandin biosynthesis in human chorion and decidual cells. Interleukin-1 beta (IL-1 beta), EGF, ionomycin (iono), and PMA are known to stimulate prostaglandin E2 production in human chorion and decidual cells. Hence, we have evaluated the effects of co-treatment of chorion and decidual cells with dbcAMP in the presence and absence of EGF, PMA, IL-1 beta, and iono on prostaglandin production. dbcAMP alone stimulated chorion and decidual PGE2 production. Coincubation of dbcAMP with all four test stimulants resulted in a further enhancement of decidual PGE2 production that was often more than additive. Thus activation of adenylate cyclase can have effects on prostaglandin production that have specificity with respect to tissue source, presence of other stimulants and relative time of exposure of the tissues to each of the substances involved.

Epidermal growth factor enhances secretion of the ovarian tumor-associated cancer antigen CA125 from the human amnion WISH cell line

OBJECTIVE

We studied the relation between epidermal growth factor (EGF)/epidermal growth factor receptor (EGFR) and CA125 production in WISH cells.

METHODS

We investigated quantitatively and immunohistochemically EGF-stimulated CA125 release from WISH cells and the effect of EGF on CA125 phosphorylation.

RESULTS

Immunohistochemical staining demonstrated that CA125 and EGFR expression on the plasma membrane of the WISH cells was closely correlated with cell density. The WISH cell monolayers (day 4) stained for CA125 in both the cytoplasm and plasma membrane. By day 8, cells began to form clumps in the surrounding monolayer that were positive for membrane-associated CA125 and EGFR, while the monolayer was almost negative for both molecules. Four-day and 8-day cells exposed to EGF demonstrated a loss of both CA125 and EGFR staining. Epidermal growth factor increased the secreted CA125 levels by 50% in day-4 cells but had no effect on day-8 cells. CA125 from WISH cells was phosphorylated, and EGF further enhanced this phosphorylation.

Protein kinase A activators inhibit agonist induced prostaglandin production in human amnion

Prostaglandin (PG) production by human amnion has been postulated to have a role in the onset of labor. Previous work by ourselves and others has demonstrated that oxytocin, phorbol esters and epidermal growth factor (EGF) increase PGE2 production in human amnion cells by activation of the Phospholipase C/Protein Kinase C (PKC) cascade system. The present study was undertaken to determine the effect of prior activation of the Adenylate Cyclase cascade system upon subsequent stimulation of PGE2 production by oxytocin, phorbol 12-myristate-13-acetate (PMA) or EGF in amnion cells and membrane discs. Isoproterenol, forskolin and dibutyryl cyclic adenosine monophosphate (dbcAMP) were utilized to activate the Adenylate Cyclase system at the receptor, enzyme and second messenger level. In control amnion cells, oxytocin, PMA and EGF each provoked dose dependent increases in PGE2 production. In cells preincubated with dbcAMP, forskolin or isoproterenol, agonist stimulated PGE2 production was markedly (50-90%) inhibited (p < 0.01). Inhibition was dose dependent upon preincubator concentrations. Maximal inhibition by adenylate cyclase activators occurred with 2-4 h of preincubation. In membrane discs, forskolin preincubation also inhibited oxytocin, PMA and EGF stimulation of PGE2 production. Activation of the Adenylate Cyclase system in human amnion cells or membrane discs inhibits the subsequent action of potent stimulators of PGE2 production in human amnion.

Transforming growth factor-beta potentiates epidermal growth factor-induced prostaglandin E2 production in amnion cells

Primary cultures of human amnion cells and the amnion-derived cell line WISH were used to evaluate the hypothesis that transforming growth factor-beta (TGF-beta) can modulate epidermal growth factor (EGF)- induced prostaglandin E2 (PGE2) production. Cells were preincubated for 1 hr with TGF-beta (0.0001-10 ng/ml) and then incubated in the presence or absence of EGF (10 ng/ml) for 4 hrs. TGF-beta alone did not stimulate PGE2 synthesis at any dose examined. However, when primary cultures of amnion cells or WISH cells were preincubated with TGF-beta and then challenged with EGF, there was a potentiation of PGE2 production that was much greater than the additive values of TGF-beta or EGF alone. These data suggest that EGF-induced PGE2 production by amnion cells can be modulated by low concentrations of TGF-beta.

Proinflammatory cytokines interact synergistically with epidermal growth factor to stimulate PGE2 production in amnion-derived cells

Recent evidence has implicated cytokines and growth factors in the initiation of parturition in women. In the present study, the amnion-derived cell line WISH was used to determine whether proinflammatory cytokines (interleukins 1 beta, 6, and 8, tumor necrosis factor-alpha, and granulocyte/macrophage colony stimulating factor) could amplify epidermal growth factor-induced prostaglandin E2 production. WISH cells were preincubated with cytokines (0.0001-10 ng/ml) for 60 min and then challenged with EGF (10 ng/ml) for 4 hrs after which PGE2 production was measured by radioimmunoassay. EGF, IL-1 beta and TNF-alpha alone caused a dose-dependent increase in PGE2 production, while IL-6, IL-8 and GM-CSF were ineffective over the dose range tested. When cells were preincubated with IL-1 beta or TNF-alpha, there was a dose-dependent potentiation of EGF-induced PGE2 production that was greater than the sum of EGF alone and IL-1 beta or TNF-alpha alone. In each case, the minimum dose of IL-1 beta or TNF-alpha which amplified EGF-induced PGE2 production was 0.1 ng/ml (p less than 0.05, Student's t-test). These data show that low concentrations of IL-1 beta or TNF-alpha may serve to amplify EGF-mediated PGE2 biosynthesis in amnion-derived cells and suggest that cytokines may modulate EGF function in responsive cells.