Abstract
The generation of germline cells from human induced pluripotent stem cells (hiPSCs) represents a milestone toward in vitro gametogenesis. Methods to recapitulate germline development beyond primordial germ cells in vitro have relied on long-term cell culture, such as 3-dimensional organoid co-culture for ~four months. Using a pipeline with highly parallelized screening, this study identifies combinations of TFs that directly and rapidly convert hiPSCs to induced oogonia-like cells (iOLCs). We demonstrate that co-expression of five TFs - namely, ZNF281, LHX8, SOHLH1, ZGLP1, and ANHX, induces high efficiency DDX4-positive iOLCs in only four days in a feeder-free monolayer culture condition. We also show improved production of human primordial germ cell-like cells (hPGCLCs) from hiPSCs by expression of DLX5, HHEX, and FIGLA. We characterize these TF-based iOLCs and hPGCLCs via gene and protein expression analyses and demonstrate their similarity to in vivo and in vitro-derived oogonia and primordial germ cells. Together, these results identify new regulatory factors that enhance human germ cell specification in vitro, and further establish unique computational and experimental tools for human in vitro oogenesis research.