The Mechanism Of M-CSF In Follicular Development And Ovulation

Infertility is common in gynecological reproductive diseases,which account for about 40%of woman.For women,the ovaries have regular ovulation is a necessary condition for fertility.According to statistics,ovulation disorders account for about 25%to 40%in female infertility.So the study of follicular development and ovulation control is always the most important in the field of assisted reproductive research.Expect the protein hormones which essentiallly originate from the pituitary,some other factors could also regulate the growing follicles.Cytokines of the inflammatory system may contribute to the modulation of ovarian function in a paracrine or autocrine fashion.People have revealed the roles of inflammatory cytokines and their binding proteins in reproduction.Macrophages are found in developing follicles,and they have been reported to promote the proliferation of granulosa cells(GCs)by secreting EGF and other cytokines.The proliferation,differentiation and activation of macrophages are mostly regulated by a homodimeric glycoprotein known as macrophage colony-stimulating factor(M-CSF;also called colony-stimulating factor-1 or CSF-1)which belongs to the family of hematopoietic growth factors.The receptor of M-CSF(M-CSFR)is a transmembrane receptor tyrosine kinase encoded by the c-fms proto-oncogene product.M-CSF can affect various cell types,including cells of the female reproductive tract.M-CSF could regulat the growth and differentiation of trophoblast,which contributes to development of the placenta.In addition,it may have a role in fetal development.In both mice and humans,M-CSF mRNA can be detected in GCs.M-CSF maybe expressed on the surface of these cells as a membrane-spanning glycoprotein or secreted into the circumstance.Witt et al.observed significantly higher concentrations of M-CSF in follicular fluid,while Nishimura et al.found that gonadotropins lead to a gradual increase in serum concentrations of M-CSF throughout ovarian stimulation,and that high concentrations of M-CSF were associated with successful oocyte retrieval.Salmassi et al.found that the serum concentration of M-CSF increased with the growth of follicles,and that a higher serum concentration of M-CSF was associated with a better in-vitro fertilization(IVF)outcome.Takasaki et al.reported that during a controlled ovarian hyperstimulation cycle,follicular development can be improved by concomitant administration of M-CSF and human menopausal gonadotrophin(hMG).All these findings suggested that M-CSF participates in the processes of follicular development and ovulation.In previous studies,we have shown that M-CSF can stimulate the production of estrodiol(E2)and progesteron(P)in luteinized GCs,and FSH enhanced M-CSF secretion by luteinized GCs.This time we invetigated the role of M-CSF in non-luteinized GCs called COV434 cell line which established from a primary human granulosa cell tumor.The essential features of normal granulosa cell function like production and secretion of estradiol after treatment with FSH,stimulation of cell growth by FSH and communication with cumulus oophorus cells can be found in this kind of cell.And the common confounder of a mixed population of cells associated with human ovarian follicle aspiration can be avoided.In the present study,we evaluated the interaction of M-CSF and FSH in the process of follicular development before ovulation,detected the alteration of E2,Nppc and NPR2 caused by M-CSF.We found that The production of FSH receptors was enhanced by M-CSF in vitro in a dose-dependent manner(P<0.05).Correspondingly,FSH was also able to promote the expression of M-CSF and its receptor when present in the appropriate concentration(P<0.05).None of these results could be affected by the addition of tamoxifen.Both FSH and M-CSF could stimulate the production of E2 by COV434 cells.We also found that M-CSF could down regulate the production of Nppc and NPR2 in vivo and in vitro,which maybe contribute to the process of ovulation.At last,we analyzed the JAK/STAT signaling pathway as a preliminary research on how M-CSF works.