Generation of human primordial germ cell-like cells from cumulus and blood cell-derived isogenic human induced...

The recent development of in vitro germ cell differentiation from pluripotent stem cells opened the human reproduction field to mechanistic investigations. In combination with induced pluripotent stem cell (hiPSC) reprogramming, in vitro gametogenesis provides an avenue for patient-specific disease modeling approaches. However, further advancements are required, as current protocols are limited to early stages of germ cell development. To get one step closer to this goal, here we aimed to identify optimal conditions for generating high-quality hiPSC lines capable of in vitro germ cell differentiation. We isolated two clinically available somatic cell types, peripheral blood-derived mononuclear cells and cumulus cells from the same female donor, and reprogrammed them into human induced pluripotent stem cells (hiPSCs). We then assessed their differentiation into ectoderm, mesoderm, and endoderm, and evaluated their X-chromosome inactivation status, a critical indicator of stem cell quality. Finally, we compared the capacity of PBMC- and cumulus-derived hiPSCs to differentiate into human primordial germ cell-like cells (hPGCLCs). We found that despite variability between cell lines, hiPSCs from both cell types were capable of generating hPGCLCs and that variations in X-chromosome state did not appear to generally interfere with the process. Our findings provide insight into germ cell differentiation from different clinically available starting materials guiding future patient-specific studies of fertility disorders.