The Hedgehog Signaling Pathway in the Mouse Ovary1

Abstract

The hedgehog (HH) signaling pathway plays an essential role in the Drosophila ovary, regulating cell proliferation and differentiation, but a role in the mammalian ovary has not been defined. Expression of components of the HH pathway in the mouse ovary and effects of altering HH signaling in vitro were determined. RT-PCR analyses show developmentally regulated expression of sonic (Shh), indian (Ihh) and desert (Dhh) HH in the ovary. Expression is detected in whole ovary, granulosa cells, and corpora lutea. The mRNAs for the two receptors, patched homolog 1 and 2 (Ptch1, Ptch2), and the signal transducer, smoothened (Smo), are also expressed. Immunohistochemistry using an antibody that detects all three HH ligands demonstrated HH protein primarily in granulosa cells of follicles from primary to antral stages of development. Follicles also stained for PTCH1 and SMO in both granulosa and theca cells. Treatment of cultured preantral follicles and granulosa cells with recombinant SHH increased growth and proliferation while treatment with the HH pathway inhibitor, cyclopamine, had no effect. Therefore, activation of HH signaling can increase cell proliferation and follicle growth but is not essential for these processes in vitro. Treatment of granulosa cells with SHH increased levels of mRNA for Gli1, a transcriptional target of HH signaling, while cyclopamine decreased expression. SHH had no effect on production of progesterone by cultured granulosa cells, while cyclopamine increased progesterone production. The results demonstrate a functional HH pathway in the follicle and identify granulosa cells as at least one of the potential targets of HH signaling.

Gene expression profiling of bovine preovulatory follicles: gonadotropin surge and prostanoid-dependent up-regulation of genes potentially linked to the ovulatory process

“…Interestingly, MTSS1 was transiently up-regulated in the granulosa layer of bovine follicles at 12 h post-GnRH injection. While a functional hedgehog signaling pathway in mouse follicles has been identified (Wijgerde et al 2005, Russell et al 2007) and effects on GC proliferation established (Russell et al 2007), the expression of hedgehog signaling components and their targets are down-regulated in mouse preovulatory follicles following hCG injection (Wijgerde et al 2005). Hence, the significance of preovulatory regulation of MTSS1 expression in bovine follicles remains unclear.…”

“…CD36 is a multifunctional scavenger receptor that binds known autocrine growth factors that can regulate cell growth, adhesion, and angiogenesis (Febbraio et al 2001). MTSS1 is a sonic hedgehog responsive actin binding protein (Callahan et al 2004) and a functional hedgehog signaling system in murine follicles has been reported (Wijgerde et al 2005, Russell et al 2007. TFG is involved in promoting NF-kappaB activity (Miranda et al 2006), which is potentially related to cumulus expansion in mice (Takahashi et al 2006).…”

The Hedgehog signaling pathway in ovarian teratoma is stimulated by Sonic Hedgehog which induces internalization of Patched

“…For immunohistochemical staining, tissues were deparaffinized, endogenous peroxidase was blocked, the slides were heated in epitope-retrieval solution for 5 min at 85˚C to enable correct epitope folding, and stained using the following antibodies diluted 1:100: goat polyclonal anti-Ptch (Santa Cruz Biotechnology Inc., Santa Cruz, CA, USA; sc-6147) (22), rabbit polyclonal anti-Smo (Santa Cruz; sc-19943) (23), rabbit polyclonal anti-Gli1 (Santa Cruz; sc-20687) (24) and rabbit polyclonal anti-Hh (Santa Cruz; sc-9024) (13). Secondary antibodies were bovine anti-goat-HRP and bovine anti-rabbit-HRP, used at 1:100 dilution.…”

“…In mammals, the Hh-Gli pathway is also involved in embryonic development of the ovary, and in the adult organism components of the pathway are expressed in reproductive tissues (12). In the adult ovary, the Hh-Gli signaling is active in the granulose cells surrounding the follicle, and it can be additionally activated by exogenous Shh protein (13).…”

Effect of purmorphamine on the mRNA expression of Sonic Hedgehog signaling downstream molecules in ovine embryo

“…HH signaling molecules exist in the murine (Wijgerde et al, 2005;Russell et al, 2007;Ren et al, 2009) and bovine (Spicer et al, 2009) reproductive systems. They are proposed to function as paracrine factors to promote cell proliferation and steroid hormone production.…”