Presentation Authors: TETSUHIRO YOKONISHI*, BLANCHE CAPEL, Durham, NC
Introduction: Somatic cells of the testis, including Sertoli cells, Leydig cells, peritubular myoid cells (PMCs), comprise the germ cell niche, and are critical to regulate spermatogenesis. Recently we discovered a drug that ablates Sertoli cells in the mouse testis 4 days after treatment, and leads to secondary loss of other somatic and germ cells 7 days after treatment. The objective of this study was to determine whether transplantation of donor testicular cells could result in engraftment of somatic lineages and restoration of spermatogenesis from the host or donor tissue.
Methods: We injected the drug into the rete testis of an adult mouse host and analyzed the effect on host cells on day 4 and day 7 after injection using cell-specific markers. We isolated donor Sertoli cells from SOX9-CFP mouse pups, and introduced these cells into Sertoli-ablated testes 4 days post drug treatment. In addition, we injected CAG-GFP neonatal mouse testicular cells into the host testes 7 days after drug treatment. To determine whether the effect of the drug was limited to mouse, we examined the drug&[prime]s effect on canine testis tissue in vitro.
Results: Four days post drug injection, Sertoli cells were eliminated. However, cord structure, vasculature and Leydig cells were intact, and spermatogonial stem cells (SSCs) survived in Sertoli-depleted tubules. When isolated Sertoli cells were injected 4 days post drug treatment, they colonized and supported host spermatogenesis (Fig. 1). In contrast, 7 days after drug treatment, tubules were depleted of both Sertoli cells and SSCs, but retained basic cord structure, and could be used as a scaffold for engraftment of both niche constructing cells and SSCs. When testicular cells were transplanted on day 7, donor Sertoli cells and SSCs settled in the tubules, and donor Leydig cells and PMCs colonized the interstitium. Donor spermatogenesis was detected 10 weeks after transplantation (Fig. 2). In addition, we found that the drug also eliminates canine Sertoli cells.
Conclusions: This drug has been used clinically for decades, and ablates both mouse and canine Sertoli cells, suggesting that this novel method to deplete and reconstitute the mouse germ cell niche can be extended to other mammals, and may be useful for male infertility patients with Sertoli cell dysfunction, or as a strategy for fertility preservation in pre-pubertal cancer patients.
Source of Funding: Japan society for the promotion of science