Sertoli cell-mediated differentiation of bovine fetal mesenchymal stem cells into germ cell lineage using an in vitro co-culture system

In vitro gamete derivation based on differentiation of germ cells (GC) from stem cells has emerged as a potential new strategy for the treatment of male infertility. This technology also has potential applications in animal reproduction as an alternative method for dissemination of elite animal genetics, production of transgenic animals, and conservation of endangered species. Mesenchymal stem cells (MSC) are multipotent progenitor cells defined by their ability to differentiate into mesodermal lineages. Under the effect of selected bioactive factors, MSC upregulate expression of pluripotent and GC specific-markers revealing their potential for GC differentiation. In addition to the effect of trophic factors, cell-to-cell interaction with Sertoli cells (SC) may be required to guide the sequential differentiation of MSC into GC. Thus, the aim of the present study was to investigate the effect of coculture with SC on the potential for in vitro GC differentiation of bovine fetal MSC (bfMSC) derived from bone marrow (BM-MSC) and adipose tissue (AT-MSC). bfMSC were isolated from male bovine fetuses and SC were collected from adult bull testes. The effect of SC interaction with BM-MSC or AT-MSC was analyzed on the expression of pluripotent factors OCT4 and NANOG, GC genes FRAGILLIS, STELLA and VASA and male GC markers DAZL, PIWIL2, STRA8 and SCP3 at Day 14 of coculture. Flow cytometry analyses detected that the majority (95,5% ± 2.5; P