CARDIOTONIC STERIODS INDUCE STRESS SIGNALING IN PREECLAMSIA: A TRANSLATIONAL APPROACH WITH IN VIVO, IN VITRO, AND PATIENT STUDIES

Objective Cardiotonic steroids (CS): marinobufagenin (MBG), ouabain (OUB) and cinobufatalin (CINO) are endogenous inhibitors of Na+/K+ ATPase. MBG is associated with preeclampsia (preE). We evaluated the effect of CS on stress signaling in pregnant rats, cytotrophoblast (CTB), and preE patients. Methods (i) Five groups of rats were studied: nonpregnant (C, n= 10); normal pregnant (NP, n = 10); pregnant rats given saline to drink and desoxycorticosterone acetate injection (PDS; preE rat model, n = 10); NP injected with MBG (NPM, n = 10); and NP injected with CINO (NPC, n = 10). We analyzed the stress signaling in all groups. (ii) Effects of CS on stress signaling in CTB were assessed. (iii) MBG and stress proteins were assayed in urine samples from 17 PreE and 23 NP patients. Results (i) Placental expression of Gadd45a, caspase 3 & 8, sFlt‐1, sFlt‐1R, & p38 were significantly higher in PDS, NPM, and NPC rats compared to NP. (ii) Expression of Gadd45a, sFlt‐1, IL‐6, 8‐IP & p38 were significantly upregulated in ≥1nM CS‐treated cells compared to vehicle‐ and 0.1 nM‐ treated cells. RNAi‐mediated inhibition of Gadd45a attenuated CS‐induced CTB stress signaling. (iii) Urinary MBG levels were significantly higher in preE patients compared to NP. Angiogenic imbalance was observed in preE patients compared to NP. Conclusions We demonstrated that CS induce the stress signaling in (i) NP rats; (ii) CTB cells; and (iii) preE patients.