New insights into the GDF9-Hedgehog-GLI signaling pathway in human ovaries: from fetus to postmenopause.

RESEARCH QUESTION: Are glioma-associated oncogene homolog 1, 2, and 3 (GLI1, 2, and 3) and protein patched homolog 1 (PTCH1) specific markers for precursor theca cells in human ovaries as in mouse ovaries?

DESIGN

To study the GDF9-HH-GLI pathway and assess whether GLI1 and 3 and PTCH1 are specific markers for precursor theca cells in the human ovary, growth differentiation factor 9 (GDF9), Indian Hedgehog (IHH), Desert Hedgehog (DHH), Sonic Hedgehog (SHH), PTCH1 and GLI1, 2 and 3 were investigated in fetal (n=9), prepubertal (n=9), reproductive-age (n=15), and postmenopausal (n=8) human ovarian tissue. Immunohistochemistry against GDF9, IHH, DHH, SHH, PTCH1, GLI1, GLI2, and GLI3 was performed on human ovarian tissue sections fixed in 4% formaldehyde and embedded in paraffin. Western blotting was carried out on extracted proteins from the same samples used in the previous step to prove the antibodies' specificity. The quantitative real-time polymerase chain reaction was performed to identify mRNA levels for Gdf9, Ihh, Gli1, Gli2, and Gli3 in menopausal ovaries.

RESULTS

Our results showed that, in contrast to mice, all studied proteins were expressed in primordial follicles of fetal, prepubertal, and reproductive-age human ovaries and stromal cells of reproductive-age and postmenopausal ovaries. Intriguingly, Gdf9, Ihh, and Gli3 mRNA, but not Gli1 and 2, was detected in postmenopausal ovaries. Moreover, GLI1, GLI3, and PTCH1 are not limited to a specific population of cells. They were spread throughout the organ, which means they are not specific markers for precursor theca cells in human ovaries.

CONCLUSION

These results could provide a basis for understanding how this pathway modulates follicle development and ovarian cell steroidogenesis in human ovaries.