Clinical studies suggest that intrauterine infection is a major medical factor association with preterm labor (PTL) in women. We hypothesize that PTL results from the synergistic interplay between signals (e.g. EGF) and inflammatory cytokines (e.g. IL-I, TNF-alpha, TGF-beta), elaborated into the decidua and/or amniotic cavity following a maternal immune response to bacterial colonization. We postulate that cytokines modulate the action of EGF by sensitizing amnion cells and, thereby, cause a robust prostaglandin synthetic response leading to premature uterine contractility and cervical dilatation. This research proposal will test the hypothesis that cytokines modulate EGF action in amnion cells using the amnion-derived cell line WISH as an in vitro model system. The EGF signal transduction cascade (i.e. receptor expression, phospholipase A2-mediated arachidonic acid release, and cyclooxygenase activation/induction) will be examined to determine whether cytokine treatment alters EGF action at one or more of these key regulatory points.
Aim 1 will address whether IL-1beta, TNF- alpha and TGF-beta, which are associated with intrauterine infection- mediated PTL can alter EGF receptor expression by (i) inducing rapid EGF receptor internalization and recycling to the cell surface and (ii) increasing the expression of EGF receptor mRNA in amnion cells.
Aim 2 will examine whether IL-1beta, TNF-alpha and TGF-beta can modulate phospholipase A2 activity and/or induction either independently or in combination with EGF in amnion cells. This question will be addressed by measuring the specific activity, PLA2 protein expression and PLA2 mRNA expression in cytokine and EGF treated cells.
Aim 3 will examine whether IL-1beta, TNF-alpha and TGF-beta can modulate cyclooxygenase activity and/or induction either independently or in combination with EGF in amnion cells. The specific activity for cyclooxygenase, and cyclooxygenase protein and mRNA expression will be measured to address this aim. Elucidating the potential control points for cytokine-mediated alterations in EGF action in amnion cells may provide a readily testable model system for understanding the biochemical details of premature activation of the prostaglandin cascade in relation to PTL.
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