EXPRESSION OF GRANULOCYTE-COLONY-STIMULATING FACTOR AND ITS RECEPTOR IS REGULATED DURING THE DEVELOPMENT OF THE HUMAN PLACENTA

The development of the placenta is dependent upon the regulated prolif eration, invasion and differentiation of trophoblast. Expression of cy tokines at the fete-maternal interface suggests that these molecules m ay participate in placentation. The expression of granulocyte-colony s timulating factor (G-CSF) and G-CSF receptor (G-CSFR) during the devel opment of the human placenta was studied by immunohistochemistry using an anti-G-CSF monoclonal antibody (mAb) and two novel anti-G-CSFR mAb s. G-CSF was present in the stroma of fetal chorionic villi and matern al decidual tissues throughout pregnancy. G-CSFR was detected at high levels in fetal first and third, but not second trimester placental ti ssues. Staining for G-CSFR was undetectable in maternal decidual tissu e from all gestational stages. In first trimester tissues, staining fo r placental G-CSFR was strongest in differentiated syncytiotrophoblast and invasive, extravillous cytotrophoblast, and weak staining was evi dent in undifferentiated cytotrophoblast. Immunohistochemical data sug gesting temporal regulation of G-CSFR were corroborated by Western blo tting and amplification by reverse transcription and PCR of G-CSFR mRN A. These data suggested that expression of G-CSFR in the human placent a is regulated both temporally and spatially, and that placental G-CSF is involved in paracrine regulation, and indicate a role for G-CSF an d G-CSFR in trophoblast growth or function during placentation.