?PRODUCTION OF REACTIVE OXYGEN SPECIES (ROS) IN EXTRAVILLOUS TROPHOBLAST CELLS: ROLE OF KRÜPPLE-LIKE FACTOR 6?

MAR DEL PLATA

Congreso; LXIII Reunión anual de la sociedad Argentina de Investigación en Clínica (SAIC); 2018

SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA

ROS are involved in cellular signaling pathways including cell proliferation,apoptosis, and migration. ROS generation and antioxidantsaction dynamic balance is critical for avoiding cell injury and evencell death by oxidative stress (OS), mainly in high-energy demandingtissues such as the placenta. Indeed, OS is associated with severalplacental dysfunctions. Krüppel like transcription factor 6 (KLF6)is known to regulate differentiation, proliferation, angiogenesis andapoptosis in different cell contexts. KLF6 immunoreactivity is higherin the placental bed of preeclamptic pregnancies than in thoseof uncomplicated pregnancies. This correlates with an increase inthe migratory capacity of KLF6-silenced HTR8/SVneo extravilloustrophoblast cells. Previous results showed an early and transient responseof KLF6 to several stressors such as: hypoxia, chlorpyrifos,H2O2 and a decrease of fetal bovine serum in the culture media.Herein, we addressed whether KLF6 modulates redox balance andthe possible pathways involved. Downregulation of KLF6 expressionin HTR8/SVneo cells transfected with a KLF6-specific siRNA (siK)led to an increase in ROS levels compared to scramble siRNA (siC)transfected cells as measured by flow cytometry using H2DCFDAdye. After 48 h of transfection, ROS levels in siK-cells were higherthan those induced in siC-cells treated with 100 μM H2O2 for3h, but cell viability was not affected. Cell cycle analysis revealed aslightly but significant increase of the population in the sub-G1 andG2/M phases in siK vs siC-cells. KLF6 downregulation also reducedcell proliferation measured by BrdU labeling. Immunofluorescence,western blot, and qRT-PCR assays revealed that neither the canonicalantioxidant Nrf2 pathway nor the unfolded protein response wereactivated. Instead, components of the unfolded protein response,involved in stress survival mechanisms, were downregulated inKLF6-silenced cells. Altogether, these results strongly suggest anew role for KLF6 in redox homeostasis of human trophoblast cells.