To determine the potential early metabolic perturbations and mitochondrial bioenergetics effects of sFlt-1 in bovine aortic endothelial cells (ECs) and first trimester extravillous trophoblasts (HTR-8/SVneo). Also, to evaluate the potential use of sepiapterin (SE), a precursor of eNOS’s cofactor tetrahydrobiopterin (BH4), in abrogating the effects of sFlt-1 in cells.
Metabolic perturbations and mitochondrial bioenergetics were assessed in ECs and HTR-8/SVneo in an in-vitro model of preeclampsia using exogenous sFlt-1 and serum from preeclamptic women. Mitochondrial bioenergetics was assessed using an XFe24 Extracellular Flux Analyzer. Nitric oxide (NO) was determined by chemiluminescence. Mitochondrial function and metabolism in sFlt-1-treated cells was evaluated also in galactose media. Mitochondrial membrane potential and superoxide was evaluated by JC-1 and Mito-Sox, respectively, by flow cytometry.
We found that treatment with sFlt-1 affected the mitochondrial maximal respiration and spare respiratory capacity in ECs in a dose dependent manner leading to a metabolic phenotype switch to glycolysis. In contrast, HTR-8/SVneo, displayed an unexpected strong glycolytic metabolism. sFlt-1 was found not to disturb the trophoblast mitochondrial metabolic and bioenergetics profile even at relatively high doses. In addition, we found that sFlt-1 treatment caused concentration dependent decreases in mitochondrial membrane potential and diminished NO levels in ECs. Moreover, treatment of ECs with sFlt-1 in galactose strongly impaired cell viability suggesting the role of sFlt-1 as a mitochondrial disruptor. SE, protected ECs and HTR8/SVneo cells from sFlt-1-induced superoxide formation and restored the NO levels and metabolic phenotype switch induced by sFlt-1 and maternal PE serum in ECs.
sFlt-1 disrupts mitochondria bioenergetics and metabolism in both, ECs and HTR-8/SVneo. This evidence could explain the potential detrimental effects of AAFs in the maternal endothelium and the hallmark of hypertension in PE. Hence, we demonstrate that SE, by enhancing BH4/NO bioavailability and diminish mitochondrial superoxide formation, restored the metabolic phenotype switch induced by sFlt-1 and PE serum. Based on this evidence, we postulate the use of SE as a potential therapeutic approach to prevent or treat PE.