Isolation, characterization, andin vitroandin vivodifferentiation of putative thecal stem cells

Abstract

Although ovarian theca cells play an indispensable role in folliculogenesis by providing follicular structural integrity and steroid substrates for estrogen production, little information is available about their recruitment, growth, and differentiation because their immature forms have not been identified. We have isolated putative thecal stem cells with the ability to self-renew and differentiate in vivo and in vitro. They are similar to fibroblasts in morphology and proliferate in vitro as round colonies with a homogenous cell population. They were induced to differentiate into early precursors and steroidogenic cells in a stepwise manner after treatment with serum, luteinizing hormone, and paracrine factors from granulosa cells. At each differentiation step, these cells displayed appropriate gene expression and morphological markers and later secreted androstenedione. The fully mature morphology was achieved by coculture with isolated granulosa cells. When transplanted into the ovaries, the putative thecal stem cells colonized exclusively in the ovarian interstitium and the thecal layer of follicles as differentiated cells. Thus, thecal stem cells appear to be present in neonatal ovaries and can be isolated, purified, and induced to differentiate in vitro. Thecal stem cells could provide an invaluable in vitro experimental system to study interactions among the oocytes, granulosa cells, and theca cells during normal folliculogenesis and to study ovarian pathology caused by theca cell dysfunction.follicle ͉ oocyte ͉ ovary

Experimental evidence showing that no mitotically active female germline progenitors exist in postnatal mouse ovaries

“…S3 A and B, white arrows). This suggests that the transplanted 12.5 dpc fetal ovarian cells contributed to the cell populations in these areas of the adult mouse ovary, which is in accordance with a previous report (12).…”

“…As various laboratories in the field have great interest in this topic but have been unable to find functional roles for the isolated cells (6,12), the key question is whether the cells purified using the DDX4 antibody are meiotically competent and can differentiate into functional oocytes. It is also of great importance to validate the conclusions drawn by Zou et al (5) and White et al (4) with an experimental approach other than an antibody-based cell purification.…”

Identification of NR5A1 (SF-1/AD4BP) gene expression modulators by large-scale gain and loss of function studies

“…It is well known that theca cells differentiate from a population of unspecialized MSCs in the ovarian stroma (Magoffin 2005). Consistent with these findings, theca stem cells, which appear similar to fibroblasts and MSCs, were isolated recently (Honda et al 2007). The presence of theca stem cells/ovarian MSCs in post-menopausal women has not been shown.…”

Plasticity of granulosa cells: on the crossroad of stemness and transdifferentiation potential

“…Putative stem cells were found in the adult ovarian surface epithelium of different mammals, including humans [61,[78][79][80], in mouse ovarian stroma [21] and in the theca layer [29], which surrounds the developing follicle.…”