40 Sepiapterin, a potential therapeutic approach to restore the metabolic phenotype switch induced by sFlt-1 in preeclampsia

Abstract

Introduction Preeclampsia (PE) is an often fatal cardiovascular complication related to pregnancy with no current effective way of treatment. Evidence of early increased circulating anti-angiogenic factors (AAFs) support the onset of a multi-systemic disorder and widespread maternal endothelial dysfunction in PE. However, the molecular mechanisms are still not well understood. Objectives 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. Methods 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. Results 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. Conclusions 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.