Production of reactive oxygen species (ROS) in extravillous trophoblast cells: role of Krüppel-like Factor 6

LUCILLE KOURDOVA; ANDREA MIRANDA; ANA CRISTINA RACCA; MARIANO CRUZ DEL PUERTO; MARIA LAURA ROJAS; SUSANA GENTI-RAIMONDI; GRACIELA M PANZETTA DE DUTARI

Congreso; LXIII Reunión Anual de la Sociedad Argentina de Investigación Clínica; 2018

SAIC SAI SAFIS

ROS are involved in cellular signaling pathways including cell proliferation, apoptosis, and migration. ROS generation and antioxidants actiondynamic balance is critical for avoiding cell injury and even cell death by oxidative stress (OS), mainly in high-energy demanding tissues suchas the placenta. Indeed, OS is associated with several placental dysfunctions. Krüppel like transcription factor 6 (KLF6) is known to regulatedifferentiation, proliferation, angiogenesis and apoptosis in different cell contexts. KLF6 immunoreactivity is higher in the placental bed ofpreeclamptic pregnancies than in those of uncomplicated pregnancies. This correlates with an increase in the migratory capacity of KLF6-silenced HTR8/SVneo extravillous trophoblast cells. Previous results showed an early and transient response of KLF6 to several stressorssuch as: hypoxia, chlorpyrifos, H2O2 and a decrease of fetal bovine serum in the culture media. Herein, we addressed whether KLF6modulates redox balance and the possible pathways involved. Downregulation of KLF6 expression in HTR8/SVneo cells transfected with aKLF6-speci􀂡c siRNA (siK) led to an increase in ROS levels compared to scramble siRNA (siC) transfected cells as measured by 􀂢owcytometry using H2DCFDA dye. After 48 h of transfection, ROS levels in siK-cells were higher than those induced in siC-cells treated with 100μM H2O2 for 3h, but cell viability was not affected. Cell cycle analysis revealed a slightly but signi􀂡cant increase of the population in the sub-G1 and G2/M phases in siK vs siC-cells. KLF6 downregulation also reduced cell proliferation measured by BrdU labeling.Immuno􀂢uorescence, western blot, and qRT-PCR assays revealed that neither the canonical antioxidant Nrf2 pathway nor the unfoldedprotein response were activated. Instead, components of the unfolded protein response, involved in stress survival mechanisms, weredownregulated in KLF6-silenced cells. Altogether, these results strongly suggest a new role for KLF6 in redox homeostasis of humantrophoblast cells.