Decidual NK Cell-Derived Conditioned Medium (dNK-CM) Mediates VEGF-C Secretion in Extravillous Cytotrophoblasts

Citation Eastabrook GDM, Hu Y, Tan R, Dutz JP, MacCalman CD, von Dadelszen P. Decidual NK cell-derived conditioned medium (dNK-CM) mediates VEGF-C secretion in extravillous cytotrophoblasts. Am J Reprod Immunol 2012; 67: 101–111 Problem The regulatory mechanisms involved in VEGF-C secretion by trophoblasts during placentation are poorly understood. We investigated whether or not decidual natural killer cell conditioned medium (dNK-CM) stimulated VEGF-C secretion in the extravillous cytotrophoblast (EVT) cell line HTR8/SVneo. Method of Study The effects of dNK-CM and recombinant IFN-γ on VEGF-C induction by HTR8/SVneo were studied in the absence or presence of IFN-γ or its receptor blocking antibodies, p38 inhibitor (SB202190), JAK inhibitor (JAK inhibitor-1, JI-1), and on STAT1 knockdown HTR8/SVneo. VEGF-C was quantified by ELISA. FACS was used to investigate the phosphorylations of Tyr701 or Ser727 of STAT1 on stimulated HTR8/SVneo. Results dNK-CM facilitated VEGF-C secretion by HTR8/SVneo. IFN-γ and IFN-γR1 or IFN-γR2 blocking antibodies reduced both dNK-CM- and IFN-γ-induced VEGF-C secretion. Phosphorylations on Tyr701 or Ser727 of STAT1 were elevated upon stimulation. Secretion of VEGF-C was reduced by treatment with SB202190, JI-1, or STAT1 knockdown by siRNA. Conclusion VEGF-C production by trophoblasts is regulated by soluble factors secreted by dNK through p38 and JAK-STAT1 pathways.