WISH Cells as a Model for the “In Vitro” Study of Amnion Pathophysiology

PARK7 regulates inflammation-induced pro-labour mediators in myometrial and amnion cells

Preterm birth is a prevalent cause of neonatal deaths worldwide. Inflammation has been implicated in spontaneous preterm birth involved in the processes of uterine contractility and membrane rupture. Parkinson protein 7 (PARK7) has been found to play an inflammatory role in non-gestational tissues. The aims of this study were to determine the expression of PARK7 in myometrium and fetal membranes with respect to term labour onset and to elucidate the effect of PARK7 silencing in primary myometrium and amnion cells on pro-inflammatory and pro-labour mediators. PARK7 mRNA expression was higher in term myometrium and fetal membranes from women in labour compared to non-labouring samples and in amnion from preterm deliveries with chorioamnionitis. In human primary myometrial cells transfected with PARK7 siRNA (siPARK7), there was a significant decrease in IL1B, TNF, fsl-1 and poly(I:C)-induced expression of pro-inflammatory cytokine IL6, chemokines (CXCL8, CCL2), adhesion molecule ICAM1, prostaglandin PGF_2α and its receptor PTGFR. Similarly, amnion cells transfected with siPARK7 displayed a decrease in IL1B-induced expression of IL6, CXCL8 and ICAM1. In myometrial cells transfected with siPARK7, there was a significant reduction of NF-κB RELA transcriptional activity when stimulated with fsl-1, flagellin and poly(I:C), but not with IL1B or TNF. Collectively, our novel data describe a role for PARK7 in regulating inflammation-induced pro-inflammatory and pro-labour mediators in human myometrial and amnion cells.

Polyunsaturated fatty acids modulate prostaglandin synthesis by ovine amnion cells in vitro

Diets or supplements high in n-3 and n-6 polyunsaturated fatty acids (PUFAs) have been shown to influence the timing of parturition. PUFAs are substrates for prostaglandin (PG) synthesis, and PGs play central roles in parturition. Hence, the effects of altering PUFA composition may be mediated through alterations in the type and relative quantities of PGs synthesised. Therefore, we have investigated the effects of a range of n-3 and n-6 PUFAs in vitro on PG synthesis by amnion cells of late gestation ewes. The n-6 PUFA, arachidonic acid (20:4, n-6), increased synthesis of two-series PGs. Degree of stimulation induced by the n-6 PUFAs was dependent on the position of the PUFA in the PG synthetic pathway, i.e. PG production of the two-series (principally prostaglandin E(2):PGE(2)) increased progressively with longer chain PUFAs. Effects of n-3 PUFAs on output of PGE(2) were more modest and variable. The two shorter chain n-3 PUFAs, α-linolenic acid (18:3, n-3) and stearidonic acid (18:4, n-3), induced a small but significant increase in PGE(2) output, while the longest chain n-3 PUFA docosahexaenoic acid (22:6, n-3) inhibited PGE(2) synthesis. Dihomo-γ-linolenic acid (20:3, n-6), the PUFA substrate for synthesis of one-series PGs, induced an increase in PGE(1) generation and a decrease in PGE(2) and PGE(3) outputs. Hence, we have demonstrated that PUFA supplementation of ovine amnion cells in vitro affects the type and quantity of PGs synthesised.

PCB 50 stimulates release of arachidonic acid and prostaglandins from late gestation rat amnion fibroblast cells

Amniotic phospholipase A2 activity contributes to elevated levels of arachidonic acid and prostaglandins observed during labor. Polychlorinated biphenyls (PCBs) activate PLA2 and have been associated with shortened gestation length. To determine if PCBs stimulate amniotic PLA2, cell cultures of rat amnion fibroblasts (RAF) were established from gestation day (gd) 20 rats and labeled with 0.5 micro Ci [3H]-arachidonic acid prior to a 0.5- or 4-h exposure to 0.1% DMSO (solvent control), PCB 50 (1-50 micro M) or TNFalpha (positive control). PCB 50 and TNFalpha induced significant release of [3H]-arachidonic acid from amnion fibroblast cells in time-dependent manners (p<0.001), an effect associated with a significant increase in iPLA2 expression (p<0.05). PCB 50 also stimulated prostaglandin production from RAF cells independent of changes in immunoreactive COX-2. These data suggest that amnion may serve as a target for PCB-induced release of arachidonic acid and uterotonic prostaglandins, with a potential for adverse pregnancy outcomes.

Nanomolar and micromolar effects of 15-deoxy-delta 12,14-prostaglandin J2 on amnion-derived WISH epithelial cells: differential roles of peroxisome proliferator-activated receptors gamma and delta and nuclear factor kappa B

15-Deoxy delta(12,14)-prostaglandin J(2) (15d-PGJ(2)), an activator of peroxisome proliferator-activated receptor (PPAR)-gamma and -delta, is a prostanoid metabolite with anti-inflammatory actions. In intrauterine tissues, proinflammatory cytokines and prostaglandins have been identified as playing key roles in the maintenance of pregnancy and the onset of labor. We investigated and compared the early (<3 h) effects of 15d-PGJ(2) with rosiglitazone (PPAR-gamma ligand) and 2-methyl-4-((4-methyl-2-(4-trifluoromethylphenyl)-1,3-thiazol-5-yl)-methylsulfanyl)phenoxy-acetic acid (GW501516) (PPAR-delta ligand) on interleukin (IL)-1beta-induced prostaglandin and cytokine production by amnion-derived WISH cells. We show that 15d-PGJ(2) exerts differential effects depending on concentration. At low concentrations (<0.1 microM), 15d-PGJ(2) inhibited IL-1beta-stimulated prostaglandin E(2) (PGE(2)) but not cytokine (IL-6/IL-8) production or cyclooxygenase-2 (COX-2) expression. This effect was attenuated by a PPAR-gamma inhibitor [2-chloro-5-nitro-N-phenyl-benzamide (GW9662)], by transfection with a dominant-negative PPAR construct, and was reproduced by the PPAR-gamma ligand rosiglitazone. At higher concentrations (1-10 microM), 15d-PGJ(2) inhibited IL-1beta-stimulated PGE(2) and cytokine production and COX-2 expression, and this effect was not blocked by GW9662. Rosiglitazone at high concentrations (1-10 microM) stimulated PGE(2) production in the absence or presence of the dominant-negative PPAR. The PPAR-delta ligand GW501516 also inhibited IL-1beta-stimulated PGE(2) production but only at high concentrations (1 microM). IL-1beta-induced nuclear factor-kappaB (NF-kappaB) DNA binding activity was significantly inhibited by 15d-PGJ(2) (10 microM) and GW501516 (1 microM) but increased with 10 microM rosiglitazone. We conclude that 1) at low concentrations, 15d-PGJ(2) acts through a PPAR-gamma signaling pathway; b) at higher concentrations, its actions are mediated most likely through other pathways such as activation of PPAR-delta and/or inhibition of NF-kappaB; and 3) rosiglitazone exerts PPAR-independent effects at high concentrations (>1 microM).