218 DISTINCT EXPRESSION OF CALCIUM TRANSPORT CHANNELS, TRPV5, TRPV6, PMCA1, NCKX3, AND CaBP-9k IN THE DUODENUM, KIDNEY, AND PLACENTA DURING PREGNANCY

Abstract

Preeclampsia is a pregnancy-specific disease characterised by concurrent development of hypertension, proteinuria, and oxidative stress in the placenta. Preeclampsia-like genetic models were also developed by modification of preeclampsia-related genes, such as catechol-O-methyltranferase (COMT). In the current study, we hypothesised that inhibition of COMT alters the expression of calcium transport genes and contributes to induction of a preeclampsia-like condition, and the treatment regimen such as calcium supplementation ameliorates the imbalanced calcium metabolism and preeclamptic symptoms. In this study, we induced COMT inhibition in mice during pregnancy to reproduce physiological conditions associated with preeclampsia. The expression of genes known as hypoxia biomarker, HIF-1a, was highly induced in the placenta of this model. The overexpression of HIF-1a demonstrates that our experimental conditions closely were similar with preeclampsia. We measured the expression of several calcium transporters (TRPV5, TRPV6, PMCA1, and CaBP-9k) in the placenta, duodenum, and kidney after COMT inhibition on gestation day 17.5 (GD 17.5). Twenty-eight mice were divided into 4 groups [Vehicle, calcium, RO41–0960, and RO41–0960 and calcium (2% of calcium carbonate)]. In addition, we evaluated the calcium transporters in the kidney and duodenum of nonpregnant female mice. The placental TRPV5,6, PMCA1, and CaBP-9k were investigated by real-time RT-PCR. All experimental data was presented mean ± standard error of the mean (s.e.m.); P-values were calculated using one-way ANOVA. Placental TRPV5, TRPV6 and PMCA1 expressions were significantly down-regulated by COMT inhibitor (ro41–0960). In addition, the reduced PMCA1 expression in the placenta was reversed by calcium supplementation. Duodenal expressions of TRPV5, TRPV6, and PMCA1 were significantly decreased in the COMT-inhibited mice, and slightly recovered after calcium supplementation. Renal expression of TRPV5, TRPV6, and PMCA1 was also decreased by COMT inhibition, while it was reversed by calcium supplementation to the level of control. Duodenal- and renal calcium transporting genes, TRPV5, TPRV6, PMCA1, and CaBP-9k, were down-regulated by COMT treatment in female mice. Taken together, these results indicate that physiological changes observed in COMT inhibition showed similar symptoms as in preeclampsia, which may be related with disturbance of calcium metabolism during pregnancy.