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

KOURDOVA, LUCILLE T; CRUZ DEL PUERTO, MARIANO; PANZETTA-DUTARI, G.M.; RACCA, ANA C.; GENTI-RAIMONDI, S.; RACCA, ANA C.; GENTI-RAIMONDI, S.; MIRANDA, ANDREA L; ROJAS, MARIA L.; MIRANDA, ANDREA L; ROJAS, MARIA L.; KOURDOVA, LUCILLE T; CRUZ DEL PUERTO, MARIANO; PANZETTA-DUTARI, G.M.

Mar del Plata

Congreso; SAIC SAI SAFIS 2018; 2018

ROS are involved in cellular signaling pathways including cell proliferation, apoptosis, and migration. ROS generation and antioxidants action dynamic balance is critical for avoiding cell injury and even cell death by oxidative stress (OS), mainly in high-energy demanding tissues such as the placenta. Indeed, OS is associated with several placental dysfunctions. Krüppel like transcription factor 6 (KLF6) is known to regulate differentiation, proliferation, angiogenesis and apoptosis in different cell contexts. KLF6 immunoreactivity is higher in the placental bed of preeclamptic 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 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 and the possible pathways involved. Downregulation of KLF6 expression in 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 H2DCFDA dye. After 48 h of transfection, ROS levels in siK-cells were higher than those induced in siC-cells treated with 100 µM H2O2 for 3h, but cell viability was not affected. Cell cycle analysis revealed a slightly but significant 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. Immunofluorescence, western blot, and qRT-PCR assays revealed that neither the canonical antioxidant Nrf2 pathway nor the unfolded protein response were activated. Instead, components of the unfolded protein response, involved in stress survival mechanisms, were downregulated in KLF6-silenced cells. Altogether, these results strongly suggest a new role for KLF6 in redox homeostasis of human trophoblast cells.