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oai:cora.ucc.ie:10468/10922023-04-04T06:58:33Zcom_10468_386com_10468_4com_10468_1com_10468_1093col_10468_387col_10468_140col_10468_1094

Both hard copy thesis and e-thesis Entire Thesis Restricted Not applicable This thesis is due for publication or the author is actively seeking to publish this material Mackrill, John Zheng, Limian Science Foundation Ireland 2013-04-27T14:43:41Z 2014-04-28T04:00:05Z 2013 2013 Trophoblasts of the placenta are the frontline cells involved in communication and exchange of materials between the mother and fetus. Within trophoblasts, calcium signalling proteins are richly expressed. Intracellular free calcium ions are a key second messenger, regulating various cellular activities. Transcellular Ca2+ transport through trophoblasts is essential in fetal skeleton formation. Ryanodine receptors (RyRs) are high conductance cation channels that mediate Ca2+ release from intracellular stores to the cytoplasm. To date, the roles of RyRs in trophoblasts have not been reported. By use of reverse transcription PCR and western blotting, the current study revealed that RyRs are expressed in model trophoblast cell lines (BeWo and JEG-3) and in human first trimester and term placental villi. Immunohistochemistry of human placental sections indicated that both syncytiotrophoblast and cytotrophoblast cell layers were positively stained by antibodies recognising RyRs; likewise, expression of RyR isoforms was also revealed in BeWo and JEG-3 cells by immunofluorescence microscopy. In addition, changes in [Ca2+]i were observed in both BeWo and JEG-3 cells upon application of various RyR agonists and antagonists, using fura-2 fluorescent videomicroscopy. Furthermore, endogenous placental peptide hormones, namely angiotensin II, arginine vasopressin and endothelin 1, were demonstrated to increase [Ca2+]i in BeWo cells, and such increases were suppressed by RyR antagonists and by blockers of the corresponding peptide hormone receptors. These findings indicate that 1) multiple RyR subtypes are expressed in human trophoblasts; 2) functional RyRs in BeWo and JEG-3 cells response to both RyR agonists and antagonists; 3) RyRs in BeWo cells mediate Ca2+ release from intracellular store in response to the indirect stimulation by endogenous peptides. These observations suggest that RyR contributes to trophoblastic cellular Ca2+ homeostasis; trophoblastic RyRs are also involved in the functional regulation of human placenta by coupling to endogenous placental peptide-induced signalling pathways. Science Foundation Ireland (RFP2007/BMIF548) Not peer reviewed Accepted Version application/pdf Zheng, L. 2013. Ryanodine receptor expression in trophoblasts. PhD Thesis, University College Cork. 242 https://hdl.handle.net/10468/1092 en University College Cork © 2013, Limian Zheng http://creativecommons.org/licenses/by-nc-nd/3.0/ Calcium Ryanodine receptor Trophoblast Ryanodine--Receptors. Calcium channels. false Ryanodine receptor expression in trophoblasts Doctoral thesis Doctoral PhD (Science) j.mackrill@ucc.ieinfo:eu-repo/semantics/openAccess