Role of the Hedgehog Signaling Pathway in Regulating the Behavior of Germline Stem Cells

Germline stem cells (GSCs) are adult stem cells that are responsible for the production of gametes and include spermatogonial stem cells (SSCs) and ovarian germline stem cells (OGSCs). GSCs are located in a specialized microenvironment in the gonads called the niche. Many recent studies have demonstrated that multiple signals in the niche jointly regulate the proliferation and differentiation of GSCs, which is of significance for reproductive function. Previous studies have demonstrated that the hedgehog (Hh) signaling pathway participates in the proliferation and differentiation of various stem cells, including GSCs in Drosophila and male mammals. Furthermore, the discovery of mammalian OGSCs challenged the traditional opinion that the number of primary follicles is fixed in postnatal mammals, which is of significance for the reproductive ability of female mammals and the treatment of diseases related to germ cells. Meanwhile, it still remains to be determined whether the Hh signaling pathway participates in the regulation of the behavior of OGSCs. Herein, we review the current research on the role of the Hh signaling pathway in mediating the behavior of GSCs. In addition, some suggestions for future research are proposed.