Human iPSC-derived fetal granulosa-like cells enhance oocyte maturation outcomes and enable multi-generational safety...

In vitro maturation (IVM) of germinal vesicle oocytes may broaden assisted reproductive technologies; however, developmental competence remains limited by the lack of standardized follicular somatic support. We generated an endogenous FOXL2-P2A-tdTomato reporter human induced pluripotent stem cell (hiPSC) line using CRISPR/Cas9 knock-in and reporter-guided transcription factor (TF) programming to produce fetal granulosa-like cells (FGLCs). A flow cytometric TF screen identified TCF21, WT1-KTS, and NR1H4 as the strongest FOXL2 inducers, and combinatorial optimization showed that removing TOX3/ETV5 and adding NR2F2 substantially increased the FOXL2-positive fraction. Bulk RNA-seq, principal component analysis, and TF activity inference positioned the induced cells close to early-gestational human fetal granulosa cell profiles. In a mouse IVM, in vitro fertilization (IVF), blastocyst culture, and embryo transfer pipeline, FGLC supplementation did not change nuclear maturation rates but improved downstream development, most clearly increasing offspring production from cumulus-oocyte complexes. A comprehensive safety assessment of F0 offspring derived from FGLC-treated oocytes revealed a normal sex ratio, postnatal growth, gross anatomy, gonadal histology, and modified SHIRPA neurobehavioral profiles. Next-generation natural mating and germ cell assays demonstrated preserved fertility, normal IVF outcomes, and normal sperm parameters in the F1 generation. These results establish a scalable strategy for generating fetal granulosa-like supporting cells from hiPSCs and provide an effective and multi-generational safety framework for oocyte-contact IVM interventions.