Targeting theGdnfGene in peritubular myoid cells disrupts undifferentiated spermatogonial cell development

Abstract

Spermatogonial stem cells (SSCs) are a subpopulation of undifferentiated spermatogonia located in a niche at the base of the seminiferous epithelium delimited by Sertoli cells and peritubular myoid (PM) cells. SSCs self-renew or differentiate into spermatogonia that proliferate to give rise to spermatocytes and maintain spermatogenesis. Glial cell line-derived neurotrophic factor (GDNF) is essential for this process. Sertoli cells produce GDNF and other growth factors and are commonly thought to be responsible for regulating SSC development, but limited attention has been paid to the role of PM cells in this process. A conditional knockout (cKO) of the androgen receptor gene in PM cells resulted in male infertility. We found that testosterone (T) induces GDNF expression in mouse PM cells in vitro and neonatal spermatogonia (including SSCs) co-cultured with T-treated PM cells were able to colonize testes of germ cell-depleted mice after transplantation. This strongly suggested that T-regulated production of GDNF by PM cells is required for spermatogonial development, but PM cells might produce other factors in vitro that are responsible. In this study, we tested the hypothesis that production of GDNF by PM cells is essential for spermatogonial development by generating mice with a cKO of the Gdnf gene in PM cells. The cKO males sired up to two litters but became infertile due to collapse of spermatogenesis and loss of undifferentiated spermatogonia. These studies show for the first time, to our knowledge, that the production of GDNF by PM cells is essential for undifferentiated spermatogonial cell development in vivo.spermatogonial stem cell | stem cell niche | male fertility | spermatogenesis | conditional gene targeting T he seminiferous epithelium is separated by tight junctions between Sertoli cells into a luminal compartment containing spermatocytes and spermatids and a basal compartment containing spermatogonial stem cells (SSCs) and spermatogonia. The basal compartment is bounded above and on the sides by Sertoli cells and below by the basement membrane of the seminiferous tubule and a layer of peritubular myoid (PM) cells. SSCs are thought to reside in a microenvironmental niche in the basal compartment, where extrinsic cues influence their decision to either self-renew or enter the pathway of spermatogonial development (1, 2). They are a minor fraction of the undifferentiated spermatogonia in the basal compartment. The other undifferentiated spermatogonia (progenitors) give rise to differentiating spermatogonia that proliferate mitotically to progress on a developmental pathway toward becoming spermatocytes (3, 4). Our current understanding of the progression of SSCs to differentiating spermatogonia comes mainly from cell kinetic studies, germ cell transplantation assays, and the use of molecular markers that identify different populations of spermatogonia.The leading model for spermatogonial development specifies that when SSCs divide, they either self-renew by becoming two type A-single (A s ) spermato...

Yangjing Capsule extract promotes proliferation of GC-1 spg cells <i>via</i> up-regulated POU3F1 pathway

“…The GDNF, secreted by Sertoli cells and peritubular myoid cells, is the major paracrine factor specifically responsible for the maintenance and self-renewal of SSCs in vivo (29,30). Other signaling pathways like insulinlike growth factor-1 receptor (IGF-1R) (31) mediated and fibroblast growth factor 2 (FGF2) (32) mediated pathways also play a role.…”

Sertoli Cell Wt1 Regulates Peritubular Myoid Cell and Fetal Leydig Cell Differentiation during Fetal Testis Development

“…Studies have shown that PMCs also secrete a number of biomolecules, such as peritubular factors that modulate Sertoli cell function (PModS) [35], fibroblast growth factor 2 (FGF2) [36], colony stimulating factor 1 (CSF1) [37], and Insulin-like growth factor 1 (IGF1) [36], which thus modulate testis microenvironment in adult animals. PMC was also found to involve in testicular growth in postnatal rat testis [38] and spermatogenesis through androgen signaling [39, 40], Lgr4-Wnt/β-catenin signaling [41] and glial cell line-derived neurotrophic factor (GDNF) [40, 42] in adult mouse testis. However, little is known about the function of PMC during fetal testis development.…”

GDNF-expressing STO feeder layer supports the long-term propagation of undifferentiated mouse spermatogonia with stem cell properties

“…Although most of the Sertoli lines established either by transgenic animals or gene infection had been widely applied for spermatogenesis mediation or investigation of Sertoli cells themselves272829, the application of Sertoli cells for SSC growth has not been validated. Recently testosterone-regulated GDNF secretion by peritubular myoid cells has also been observed, which ensured the optimal GDNF level for repopulating the undifferentiated spermatogonia including SSCs30. However, testis somatic cell feeders were likely to inhibit SSCs survival and replication in vitro 9, and it is unknown whether the overexpression of GDNF and/or other growth factors in STO or MEF could support SSC survival or the long-term proliferation of a SSC line.…”