Expression and function of PSG, StarD7 and KLF6 genes in human trophoblast cells

PANZETTA DE DUTARI G.; RACCA A; CAMOLOTTO S; RIDANO ME; FLORES-MARTIN, J; RENA V.; GENTI DE RAIMONDI S

Rio de Janeiro

Congreso; X International Congress on Cell Biology. International Federation for Cell Biology (IFCB) and the Brazilian Society for Cell Biology; 2012

International Federation for Cell Biology (IFCB) and the Brazilian Society for Cell Biology

Expression and function of PSG, StarD7 and KLF6 genes in human trophoblast cells Graciela M Panzetta-Dutari., Racca AC., Camolotto S., Ridano ME., Flores-Martin J., Rena V. & Genti-Raimondi S. Placenta is intimately related to fetal and maternal health. Villous cytrophoblasts (CTB) differentiate by fusion to form the syncytiotrophoblast (STB) layer characterized by a high metabolic and biosynthetic activity. Human pregnancy- specific glycoproteins (PSG) are the major STB secreted proteins at term, and low PSG levels have been associated with complicated pregnancies. Steroidogenic acute regulatory protein-related lipid transfer domain containing 7 (StarD7) has a wide-spread expression in trophoblastic tissues with highest levels in choriocarcinoma cells, and KLF6 knockout mice exhibit impaired placental development. In order to further elucidate gene expression control and function of these proteins in placental biology, we performed microscopy, qRT-PCR, western-blot, transfection, siRNA, DNA- protein interaction and immunoprecipitation assays, among others, in human trofoblastic cell models. We found that PSGs are early differentiation markers whose expression precedes that of hCG and cell fusion. PSG promoter activation involves regulation by Sp1, KLF6, acetylation/ deacetylation balance and 5`proximal sequences. Remarkably, KLF6 peaks early during the syncytialization process, transactivates PSG and hCG genes, and KLF6 down-regulation inhibits CTB fusion, suggesting it is an essential regulator of trophoblast differentiation. StarD7 expression is regulated by SF-1 and Wnt--catenin signaling which might have important implications in phospholipid uptake and transport contributing to trophoblast development. Finally, as an increased risk of pregnancy alterations has been reported in women chronically exposed to pesticides, we investigated chlorpyrifos effect on trophoblast cells. Exposures to concentrations which did not alter cell viability and fusion modified KLF6, hCG, GCM1, ABCG2, and P-gp but not PSG and StarD7 gene expression. These studies have provided a better understanding about the molecular players involved in trophoblast cell biology and hence in pregnancy maintenance. This study was conducted with the ethics approval from the Human Studies Local Committee. It was supported by CONICET, FONCyT, MinCyT of Córdoba and SECyT-UNC