Oxidative stress decreases uptake of neutral amino acids in a human placental cell line (BeWo cells)

Increased oxidative stress (OS) is implicated in the pathophysiology of several pregnancy disorders. We aimed to investigate the effect of tert-butylhydroperoxide (TBHP)-induced OS upon the placental transport of the neutral amino acids L-methionine (L-Met) and L-alanine (L-Ala), by using a human trophoblast cell model (BeWo cells). TBHP reduced both total and Ne-independent C-14-L-Met intracellular steady-state accumulation over time (A(max)), by reducing non-system L-mediated uptake - most probably system y(+) while having no effect on system L. Moreover, TBHP reduced total C-14-L-Ala A(max) through an inhibition of system A. The effect of TBHP upon total, but not system A-mediated, C-14-L-Ala uptake was dependent upon phosphoinositide 3-kinase (PI3K) and protein kinase C (PKC) activation, and was completely prevented by the polyphenol quercetin. In conclusion, a reduction in placental uptake of neutral amino acids may contribute to the deleterious effects of pregnancy disorders associated with OS. (C) 2013 Elsevier Inc. All rights reserved.