Upregulation of autotaxin by oxidative stress via Nrf2 activation: A novel insight into the compensation mechanism in preeclamptic placenta

The response of autotaxin (ATX)-lysophosphatidic acid (LPA) signaling system to placental oxidative stress (OS) and its significance to preeclampsia were investigated. For this purpose, oxidative stress index (OSI) and ATX levels were measured in the serum of pregnant women with preeclampsia. The expression levels of ATX and LPA receptors were assessed in trophoblast cells under high OS and glucose deprivation/re-oxygenation (OGD/R) conditions, with particular emphasis on the antioxidative nuclear factor erythroid 2-related factor 2 (NRF2) pathway. The influence of ATX-LPA signaling on cell migration was also evaluated using the wound healing assay. ATX concentrations and OSI in the serum were found to be elevated in preeclamptic women. The serum ATX levels were also positively correlated with OSI. Trophoblast cells responded to OS by increasing ATX mRNA expression concomitantly with intranuclear translocation of Nrf2, whereas inhibition of Nrf2 activation reverted this effect. The ATX-LPA signaling pathway facilitated trophoblast cell motility after Nrf2 activation. In conclusion, OS accumulation in preeclamptic placenta may activate the ATX-LPA system in trophoblasts via the Nrf2 pathway to sustain trophoblast functionality.