Proceedings of The Physiological Society

Physiology 2016 (Dublin, Ireland) (2016) Proc Physiol Soc 37, PCA337

Poster Communications

Potential use of Sulforaphane to reverse deficits in Nrf2-mediated redox defences and protect the fetal vasculature following in utero exposure to adverse pregnancy

S. Chapple1, K. Farrell-Dillon1, P. Taylor2, G. E. Mann1

1. Cardiovascular Division, King's College London, London, United Kingdom. 2. Women's Health, King's College London, London, United Kingdom.

Gestational diabetes (GDM) is classified as first onset of diabetes during pregnancy and its prevalence is increasing due to the growing obesity epidemic. Several studies highlight a strong association between in utero exposure to GDM and increased risk of later-life insulin resistance and vascular dysfunction. In fetal GDM endothelial cells challenged with endogenous oxidative stimuli such as 4-hydroxynonenal (HNE), we previously identified deficits in protective Nrf2-mediated redox defences which parallel markers of oxidative damage including DNA fragmentation, protein oxidation and enhanced mitochondrial ROS generation. Here we examined whether (I) Nrf2 activation in response HNE could be restored using the dietary Nrf2 activator Sulforaphane (SFN) in GDM human fetal endothelial cells, (II) whether Nrf2 redox defenses are compromised in a murine model of insulin-resistant obesogenic pregnancy and (III) whether SFN can cross the placenta to induce fetal Nrf2 gene expression in vivo. Fetally derived normal and GDM umbilical vein endothelial cells (HUVEC) were pre-treated with or without SFN (2.5µM 24h) before challenge with HNE (20µM 12h) and assessment of downstream gene expression by immunoblot or as an index of oxidative damage, protein carbonylation by oxyblot. In other experiments, fetal hearts taken from high-fat diet (HFD) insulin-resistant C57BL/J6 dams mice were used to assess basal Nrf2 signalling by qPCR. Similarly, maternal and/or fetal hearts were isolated from normal chow fed dams given SFN (I.P 5mg/kg 24h or diet 0.5mg/kg 5days) before assessing Nrf2 and target gene expression by qPCR or immunoblot. In GDM HUVEC, SFN pre-treatment restores Nrf2 target gene NQO1 and GCL induction in response to HNE and prevents enhanced protein oxidation of GDM HUVEC. To examine whether SFN may restore Nrf2 signalling in vivo, we examined basal Nrf2 signalling in murine fetal heart tissue taken from HFD insulin-resistant pregnancies. Despite exposure to a HFD, no basal compensatory increase in Nrf2 target genes such as NQO1, HO-1 or GCL was observed in HFD fetal hearts. In normal chow fed animals, IP or dietary SFN administration could increase Nrf2 and downstream target genes such as HO-1 and GCL in maternal heart, placenta and fetal heart. In summary, our findings suggest exposure to SFN may alleviate oxidative stress-induced fetal vascular damage associated with human GDM pregnancy. Our findings in normal chow fed mice demonstrating SFN can induce maternal and fetal Nrf2 antioxidant gene expression in vivo further support the therapeutic potential of Sulforaphane which we will explore in our murine model of obesogenic insulin-resistant pregnancy.

Where applicable, experiments conform with Society ethical requirements