The role of the NOTCH pathway members in the development of Pre-eclampsia

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dc.contributor.advisor Ponnampalam, A en Takele, Elleni en 2016-07-26T02:28:29Z en 2016 en
dc.identifier.citation 2016 en
dc.identifier.uri en
dc.description Full text is available to authenticated members of The University of Auckland only. en
dc.description.abstract Pre-eclampsia is a serious pregnancy complication, affecting 3 to 8% of pregnancies. It is characterized by high blood pressure and the presence of protein in the urine. The only known cure for the disease is the delivery of the placenta and the baby. Inadequate placentation and poor placental perfusion are key features of preeclampsia. A primary impairment in pre-eclampsia is inadequate trophoblast invasion of the maternal arteries preventing the formation of low resistance spiral arteries. Endothelial cell dysfunction early on is also associated with the development of preeclampsia resulting in increased vascular resistance and reduced placental perfusion. The molecular mechanisms responsible for this poor placentation are poorly understood. The objectives of this study were: (i) To characterize components of the NOTCH pathway in human placental tissues of normal and pre-eclamptic pregnancies; (ii) to determine the role of Notch signalling in trophoblast and endothelial cell function in vitro. Normal term placentas were obtained following C-section without labour and vaginal delivery. Placental tissues from pregnancies complicated by preeclampsia and gestational matched controls were obtained from the Otago Placenta Study (OPuS) bio bank. Gene and protein expression was determined by real-time PCR and western blotting, respectively. In addition, HTR8/SVneo cells (first trimester extra villous trophoblast cell line) and human microvascular endothelial cells (HMECs) were treated with 5μM DAPT, a small molecule inhibitor of NOTCH, for 24 and 48 hours prior to running functional assays. NOTCH inhibition on (i) migration and invasion was tested using transwell assays; (ii) angiogenesis was assessed by Matrigel tube formation assays. mRNA expressions of all NOTCH receptors and ligands were significantly lower in normal term placentas following labour compared with Csection. Protein expression of NOTCH3 and NOTCH4 receptors were significantly decreased in placentas from pregnancies complicated with pre-eclampsia compared to their gestational matched controls. Inhibition of NOTCH pathway resulted in significant down-regulation of expressions of NOTCH target genes such as HES1, SNAI2 and TGF-β in HTR8 cells in vitro. These genes regulate processes such as invasion, migration and epithelial mesenchymal transition (EMT). This was also accompanied by significant reduction in protein expressions of mesenchymal markers, Vimentin and β-catenin. NOTCH pathway inhibition in turn, significantly reduced trophoblast invasion and migration. In addition, inhibition of NOTCH significantly inhibited the tube formation of HMECs. However, the treatment had no significant effect on cell viability. The results from this project imply that the Notch pathway regulates trophoblast invasion and migration and angiogenesis. Given that NOTCH pathway members have already been shown to be deregulated in placentas from pregnancies complicated by pre-eclampsia, a targeted induction of this pathway may have important therapeutic implications. en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof Masters Thesis - University of Auckland en
dc.relation.isreferencedby UoA99264869708902091 en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. en
dc.rights Restricted Item. Available to authenticated members of The University of Auckland. en
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dc.title The role of the NOTCH pathway members in the development of Pre-eclampsia en
dc.type Thesis en Physiology en The University of Auckland en Masters en
dc.rights.holder Copyright: The Author en
pubs.elements-id 536341 en
pubs.record-created-at-source-date 2016-07-26 en

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