Human fetal uterine cells: culture, characterization, and analysis of growth factor receptor gene expression

Peptide growth factors are postulated to have a role in uterine maturation during organogenesis. The purpose of this investigation was to establish a model to study human fetal uterine development. To that end, we describe an in vitro culture system and have characterized the cell types present during the period of uterine maturation. In addition, we evaluated the pattern of growth factor receptor gene expression in these cultured cells. Uteri were dissected from human first and second trimester fetuses (n = 20). Characterization studies were performed against three intermediate filament proteins, cytokeratin, vimentin, and desmin, and against a fibroblast-associated cell surface antigen. Ribonucleic acid was extracted from pure stroma-like cultures, and reverse transcription-polymerase chain reaction (RT-PCR) was used to amplify sequences specific for the epidermal growth factor receptor (EGF-R), fibroblast growth factor receptor (FGF-R), and the insulin receptor (I-R). Two predominant cell types were identified in the cultured fetal tissue: stroma-like cells and clusters of uterine epithelium. Immunofluorescent studies demonstrated positive expression of cytokeratin, vimentin, and a fibroblast-associated antigen in the fetal stroma-like cells, in contrast to adult stromal cells, which consistently expressed only vimentin. Using RT-PCR, the uterine cells were positive for the EGF-R, two forms of the FGF-R, and two forms of the I-R. In conclusion, we provide the first report of a human fetal cell culture system. Characterization studies of fetal stroma-like cells demonstrate immunoreactivity to vimentin, cytokeratin, and a fibroblast antigen, in contrast to the adult stromal cell, which consistently expressed only vimentin. Using RT-PCR, we found that messenger ribonucleic acids for the EGF-R and two forms of both the FGF-R and I-R are expressed. This model may be useful for studying the dynamics of human uterine development in vitro.