Assessment of Krüppel-like factor 6 function in human extravilloustrophoblast cells

MIRANDA A.L.; RACCA A.; KOURDOVA L.

Buenos Aires

Congreso; LIII Reunión Anual de SAIB 2017; 2017

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Oxidative stress implies an imbalance between the generation of reactive oxygen species (ROS) and their clearance by defensive antioxidant molecules and mechanisms. Normal pregnancy requires an active placental antioxidant system to keep ROS level under control. Adequate levels are required for normal trophoblast proliferation, invasion, and angiogenesis. But, impaired redox homeostasis is associated with miscarriage, preeclampsia, intrauterine growth restriction, and preterm birth. Krüpple-like factor 6 (KLF6) is a ubiquitous transcription factor enriched in the placenta. It has been implicated in angiogenesis, proliferation, apoptosis, and differentiation. However, its function is highly dependent on the cell context. We have previously demonstrated that KLF6 regulates the expression of pregnancy related genes such as PSG and β-hCG, is required for proper trophoblast syncytialization, and hypoxia induces its expression in term human placenta and extravillous trophoblastic cells. Herein, we evaluated whether KLF6 contributes to ROS balance in HTR8/SVneo cells, a cell line derived from first trimester human extravillous trophoblasts. KLF6 expression was early up-regulated in response to chemical hypoxia, decreased serum concentration, and treatment with chlorpyrifos, a pesticide that generates ROS. KLF6 expression was down-regulated with a specific siRNA (siK) or a non-targeting siRNA (siC). Cell viability was not compromised after 48 h of transfection; however, a significant increase in ROS level was detected by flow cytometry in siK-cells compared to siC ones. In addition, higher levels of ROS were detected in siK-cells after 3 and 6 h of H2O2 treatment. Moreover, upon exposure to H2O2 for 24 h viability was dramatically reduced in KLF6-silenced cells compared to siC transfected and non-transfected cells. Altogether, these results suggest that KLF6 contributes to extravillous trophoblast survival under oxidative stress conditions. Supported by FONCyT, CONICET, SECyT-UNC.