Modelling preeclampsia: a comparative analysis of the common human trophoblast cell lines

Preeclampsia remains a challenge without an effective therapy. Evidence supports targetability of soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin (sEng), which are released excessively from the placenta under ischemic and hypoxic stresses. We compared four trophoblast cell lines, BeWo, Jar, Jeg-3, and HTR-8/SVneo, in order to identify a suitable model for drug screening. Cultured trophoblasts were exposed to 1% oxygen vs. normoxia for 24-48 hr; human umbilical vein and aortic endothelial cells were included for comparison. Supernatant sFlt-1 and sEng concentrations were measured by ELISA, and sFlt-1 mRNA expression determined by RT-PCR. Cellular responses to experimental therapeutics were explored. All four trophoblast lines secreted sEng, which did not increase by hypoxia. BeWo, Jar, and Jeg-3 exhibited significantly enhanced expression of sFlt-1 i13 and e15a mRNA in response to hypoxia; however, only BeWo released a detectable level of sFlt-1 protein, which was doubled by hypoxia. In contrast, hypoxia decreased sFlt-1 mRNA expression and protein release in HTR-8/SVneo, similarly to endothelial cells. The cellular mechanism involved HIFα. BeWo responded to representative agents similarly to human primary placental tissues in the literature. These data support that the BeWo-hypoxia model mimics a key pathogenic mechanism of preeclampsia and has potential value for translational drug discovery.