PI3K/Akt, MAPK Erk1/2 and NFkB are involved in G-CSF-induced MMP-2 activity and VEGF secretion in a human trophoblastic cell line

FURMENTO V.A.; MARINO V.J.; L. P. ROGUIN

Bariloche, Argentina

Simposio; The Second South American Spring Symposium in Signal Transduction and Molecular Medicine; 2012

J. Silvio Gutkind (NIDCR ? NIH), Roger Davis and Lucio H Castilla (University of Massachusetts Medical School), together with Adali Pecci and Omar A. Coso (University of Buenos Aires ? Argentina).

Granulocyte-Colony Stimulating Factor (G-CSF) is a potent hematopoietic cytokine that exerts its biological role through the interaction with cell surface G-CSF Receptors (G-CSFR). The presence of G-CSFR has not only been reported in the myeloid linage, but also in non-hematopoietic tissues. In particular, the relevance of G-CSF signaling and regulation in placental tissue still remains to be studied. Previously, we demonstrated the presence of functional G-CSF receptors in the human Swan71 trophoblastic cell line, and found that G-CSF:receptor interaction is related to an increase in the activity of metalloproteinase-2 (MMP-2) and the levels of Vascular Endothelial Growth Factor (VEGF). The aim of this work was to examine the involvement of some signaling pathways in these biological outputs. When Akt and MAPK Erk1/2 phosphorylation kinetics were studied by Western blot (WB), maximum levels of Erk1/2 and Akt phosphorylation were obtained after 60 and 15 min of incubation with 1 µg/ml G-CSF, respectively. Since PI3K/Akt pathway is involved in NFkB activation, we decided to study the degradation kinetics of its inhibitor (IkB) and the translocation of the transcription factor to the nucleus. WB assays showed that IkB levels significantly diminished after 16 h of exposure to 1 µg/ml G-CSF, whereas NFkB nuclear translocation was evident after 24 h. Furthermore, results obtained by using specific signaling pathways inhibitors, such as PD 98059, Ly 294002 and Bay 11-7082, suggested that the pathways herein studied would be participating in the biological actions triggered by the cytokine. In conclusion, our data suggest that PI3K/Akt, Erk1/2 and NFkB pathways would be implicated in the G-CSF-induced increase of MMP-2 activity and VEGF secretion in human Swan71 trophoblastic cells.