CELLULAR TARGETS FOR ABUSABLE DRUGS IN HUMAN PLACENTA

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DESCRIPTION: (Applicant's Abstract) Abuse of illicit drugs during pregnancy is currently a serious concern pertaining to women's health because of the deleterious effects these drugs have on the mother and on the fetus. The objective of the current project is to investigate the role of placenta in the pathogenesis of complications arising from abuse of cocaine and amphetamines during pregnancy and to establish that placenta is a direct target for these drugs. Human placenta expresses the serotonin transporter and the norepinephrine transporter, both of which are targets for cocaine and/or amphetamines. These transporters most likely function in the clearance of the vasoactive monoamines serotonin and norepinephrine from the intervillous space. Interference with their functions by cocaine and amphetamines would have had effects on the developing fetus. The current project will investigate the normal function, regulation, and ontogeny of these two transporters in the placenta. Studies will include detailed characterization of the interaction of cocaine and amphetamines with these two transporters. These studies will be done with isolated plasma membrane vesicles from the placenta and also with intact trophoblast cells and choriocarcinoma cells. The placental syncytiotrophoblast is a polarized cell and immunolocalization studies will be performed to determined whether or not the expression of the serotonin and norepinephrine transporters is polarized with regard to the maternal-facing brush border membrane and the fetal-facing basal membrane. Proposed studies will also delineate the differential role of hormones/cytokines in the modulation of these transporters using primary trophoblast cultures and choriocarcinoma cells. These studies will include analysis of hormone/cytokine-induced changes in the transport activity, transporter density and steady state levels of transporter-specific mRNAs. The specific signalling pathways mediating the hormone/cytokine effects will be identified and the involvement of transcriptional and translational processes and posttranslational modifications in the regulation will be delineated. Studies will also test the hypothesis that impaired function of one or both of these transporters is a pathogenic factor in preeclampsia, a condition which clinically resembles in many respects the complications arising from use of cocaine and amphetamines during pregnancy. The ontogenic development of the serotonin and norepinephrine transporters in placenta will be studied using the rat as the experimental model.