Autocrine/paracrine influences of pro and antiinflammatory cytokines and growth factors in the fetal membranes appear central to the synthesis of many effectors in the onset of labor at term and in infection-induced preterm labor. We have shown that II-1beta can coordinately induce expression of cytosolic phospholipase A2 (cPLA2) and prostaglandin H synthase-2 (PGHS-2) in amnion-derived WISH cells and both enzymes localize on the nuclear membrane. The two enzymes may be coupled to give localized arachidonic acid mobilization and PG synthesis. Inhibition of cPLA2 activity blocks cytokine-stimulated PG synthesis and cPLA2 knockout mice fail to deliver at term showing a central role for cPLA2 mediated PG release in the process of parturition. The catalytic activity of cPLA2 is stimulated by phosphorylation by agonists such as EGF. We have preliminary evidence for involvement of p38 MAP kinase in this pathway. Both epithelial and mesenchymal cells in amnion express PGHS-2 at term labor but respond differently to glucocorticoids. Both express cPLA2 and the mesenchymal cells express inducible nitric oxide synthase highlighting a potential role for them in signalling the onset of labor.
We aim to: 1. Determine if phosphorylation of cPLA2 by 11-1beta or EGF in WISH cells gives association with a specific nuclear fraction (nuclear membrane or endoplasmic reticulum) to cause arachidonic acid mobilization and co-localization with PGHS-2. 2. Utilize specific inhibitors and western blots to determine if II-1beta or EGF stimulated cPLA2 phosphorylation and cPLA2/PGHS-2 mRNA expression in WISH cells occurs via the p38 MAP kinase, ERK-1,2 or protein kinase C pathways. 3. Determine if lipopolysaccharide (LPS), which stimulates PGE2 Synthesis by WISH cells, causes phosphorylation of cPLA2 via p38 MAP kinase and if LPS treatment of cells primes cells for the subsequent action of cytokines. 4. Determine the role of pro and antiinflammatory cytokines, (II-1beta, II-4 and II-10) and growth factors (TGFbeta) on cPLA2 phosphorylation and activation in WISH cells and the interaction of these cytokines with LPS. 5. Determine changes in the expression, phosphorylation (activation) of cPLA2 and association with the nuclear membrane (with PGHS-2) in amnion tissue from patients at term or preterm, either in or not in labor. 6. Determine if p38 MAP kinase stimulated phosphorylation of cPLA2 occurs in amnion epithelial and mesenchymal cells and if glucocorticoids differentially affect cPLA2 expression in these cells as they have been shown to do for PGHS-2. This study will provide novel data on phosphorylation and activation of cPLA2 in human amnion tissue and further define the role of this crucial regulatory step in eicosanoid synthesis in the fetal membranes at parturition.
|Guo, Chunming; Wang, Wangsheng; Liu, Chao et al. (2014) Induction of PGF2? synthesis by cortisol through GR dependent induction of CBR1 in human amnion fibroblasts. Endocrinology 155:3017-24|
|Guo, Chunming; Li, Cun; Myatt, Leslie et al. (2013) Sexually dimorphic effects of maternal nutrient reduction on expression of genes regulating cortisol metabolism in fetal baboon adipose and liver tissues. Diabetes 62:1175-85|
|Guo, C M; Kasaraneni, N; Sun, K et al. (2012) Cross talk between PKC and CREB in the induction of COX-2 by PGF2? in human amnion fibroblasts. Endocrinology 153:4938-45|
|Wang, Weihua; Guo, Chunming; Li, Wenjiao et al. (2012) Involvement of GR and p300 in the induction of H6PD by cortisol in human amnion fibroblasts. Endocrinology 153:5993-6002|
|Guo, Chunming; Yang, Zhen; Li, Wenjiao et al. (2008) Paradox of glucocorticoid-induced cytosolic phospholipase A2 group IVA messenger RNA expression involves glucocorticoid receptor binding to the promoter in human amnion fibroblasts. Biol Reprod 78:193-7|
|Yang, Zhen; Guo, Chunming; Zhu, Ping et al. (2007) Role of glucocorticoid receptor and CCAAT/enhancer-binding protein alpha in the feed-forward induction of 11beta-hydroxysteroid dehydrogenase type 1 expression by cortisol in human amnion fibroblasts. J Endocrinol 195:241-53|
|Sun, Kang; Brockman, Diane; Campos, Begona et al. (2006) Induction of surfactant protein A expression by cortisol facilitates prostaglandin synthesis in human chorionic trophoblasts. J Clin Endocrinol Metab 91:4988-94|
|Sun, K; Qu, X; Gao, L et al. (2006) Dexamethasone fails to inhibit the induction of cytosolic phospholipase A(2) expression by interleukin-1beta in cultured primary human amnion fibroblasts. Placenta 27:164-70|
|Sun, Kang; Myatt, Leslie (2003) Enhancement of glucocorticoid-induced 11beta-hydroxysteroid dehydrogenase type 1 expression by proinflammatory cytokines in cultured human amnion fibroblasts. Endocrinology 144:5568-77|
|Meadows, Juliana W; Eis, Annie L W; Brockman, Diane E et al. (2003) Expression and localization of prostaglandin E synthase isoforms in human fetal membranes in term and preterm labor. J Clin Endocrinol Metab 88:433-9|
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