S. Sakakura

Detection and localization of interleukin-8 mRNA and protein in human placenta and decidual tissues

It has been reported that interleukin-8 (IL-8) is secreted from the placental and decidual tissues and that IL-8 levels in the amniotic fluids are significantly elevated by chorioamnionitis or labor pain. The present study was aimed at defining the localization of IL-8 mRNA as well as IL-8 protein at the feto-maternal interface using in situ hybridization and immunohistochemical staining. Both IL-8 mRNA and protein were localized in cytotrophoblast, syncytiotrophoblast and Hofbauer cells of the placenta, decidual stromal cells, decidual lymphocytes and endometrial gland cells. IL-8 secretion from glandular cells has not previously been reported. In addition, we confirmed IL-8 mRNA expression and secretion of IL-8 by an endometrial cancer cell line (Ishikawa) using the reverse transcriptase-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) methods, respectively.

LOCALIZATION OF STEM CELL FACTOR (SCF) AND c-kit mRNA IN HUMAN PLACENTAL TISSUE AND BIOLOGICAL EFFECTS OF SCF ON DNA SYNTHESIS IN PRIMARY CULTURED CYTOTROPHOBLAST

The supernatant of homogenized human placental tissues at early and late stages of pregnancy were found to contain 40-100 pg of stem cell factor (SCF)/mg of total protein by enzyme linked immunosorbent assay. When the SCF mRNA expression was examined by reverse transcriptase-polymerase chain reaction (RT-PCR), the secretory type and membrane-bound type SCF mRNA were detected in the human placental tissues in the early stages of pregnancy and in a human placental cell line;tPA30-1 cells. However, the secretory type SCF mRNA was predominant and membrane-bound type SCF mRNA was absent or very weak in the term placental tissues. When the distribution of SCF mRNA and c-kit mRNA in the placental tissues was examined by in situ hybridization, SCF mRNA was detected in the cytotrophoblast, the intermediate trophoblastic cell column and the stromal cells, while c-kit mRNA was detected in the cytotrophoblast and the intermediate trophoblastic cell column. Both c-kit and SCF mRNA were absent or very weak in the syncytiotrophoblasts. The supernatant of primary cultured cytotrophoblasts and tPA30-1 cells were found to contain SCF. In cytotrophoblasts in the early stage of pregnancy cultured in the presence of recombinant human secretory type SCF, DNA synthesis was increased depending on the SCF concentration. These findings indicate that SCF is a cytokine which promotes the growth of placental cells by the autocrine and paracrine mechanism.