Progenitor cells harvested from bovine follicles become endothelial cells

Hematopoietic-like colonies develop in post-confluent granulosa cell cultures derived from bovine antral follicles. Previously, we had shown that these colonies gave rise to macrophages. In the present study, we validated the presence of somatic KIT-positive (KIT+) progenitor cells in colony-containing granulosa cell cultures. The cultures expressed the progenitor cell markers Sox-2, Oct 3/4, KIT, and alkaline phosphatase in western blot analysis. The successful double immunofluorescence localization of KIT and CD14, CD45, CD133, or VEGF-R2 revealed a specific subpopulation of progenitor cells. Flow cytometry showed that cells doubly positive for KIT and CD14 or CD45 comprised less than 10% of the population. The KIT+ cells were purified by magnetic selection and differentiated with the hanging drop technique using haematopoietic differentiation medium. Pure cultures of either granulosa cells or endothelial cells were obtained. The spindle-shaped and epithelioid phenotypes indicated endothelial cell heterogeneity of microvascular source. We conclude that progenitor cells are obtained from the follicle harvest, which differentiate into endothelial cells. The cells are relevant for findings to angiogenesis and luteinization of the corpus luteum.