204. Proteomic analysis of the effluent from perfused placental cotyledons identifies proteins associated with pre-eclampsia

Abstract

Pre-eclampsia (PE) is proposed to involve maternal systemic endothelial cell dysfunction which may be caused by excessive shedding of syncytiotrophoblast microparticles (STBM) from the placenta into the maternal circulation. We have examined STBM harvested by perfusion of placental cotyledons from PE and gestation-matched control (GMC) pregnancies. Following proteomic analysis, the proteins Calreticulin, Chloride intracellular channel 3 (CLIC3), Valosin-containing protein (VCP), Protein disulfide-isomerase A3 (ERp57) and Protein kinase C inhibitor protein 1 (14–3-3) were identified as having increased expression in PE samples. This result suggests that there may be increased rate of release of these proteins from the placenta into the maternal circulation. The aims of this work are to measure the expression of these proteins in placental extracts and maternal plasma, and to compare expression between PE and GMC using western blots and/or ELISA with antibodies specific to each protein. Placental expression was confirmed for all five proteins, however, CLIC3 was the only protein significantly increased in the placenta in PE (17.858µg+1.62, n = 27, t-test P < 0.05) compared with GMC (10.478µg+0.76, n = 25). western blot determined there was a significant increase in calreticulin expression in plasma from PE women compared with GMC (as shown by Gu et al. 2008). Likewise, VCP was also increased in PE plasma (1810+280 density/0.25µl, n = 10) compared with GMC (884+260, n = 9). In contrast, the protein 14–3-3 was decreased in PE plasma (4 out of 27 PE plasma samples tested expressed 14–3-3) compared with GMC (10 out of 27 control plasma samples expressed 14–3-3). One of the western blots determined that there was a significant decrease in 14–3-3 expression in plasma from PE women (199.24+186 density/2.5µl, n = 10, un-paired t-test P < 0.05) compared with GMC (2174.91 ± 723.29, n = 11). Neither ERp57 nor CLIC3 was detected in maternal plasma. Those proteins found to be significantly different in PE compared with GMC may be involved in the pathophysiology of PE. These results demonstrate that proteomic analysis of the effluent from perfused placental cotyledons is a reliable screening method to successfully identify proteins that have altered expression with PE.

(1) Gu et al. Mole. Human Repro. April 16 2008