Theca Stem Cell Differentiation into Primordial Germ Cell-like Cells Reveals GTSF1 and L1TD1 as Candidate Molecular Markers
Diminished ovarian reserve (DOR) is a major contributor to female infertility, and stem cell-based strategies for oocyte generation have gained increasing attention. Theca stem cells (TSCs), as multipotent progenitors located within ovarian follicles, represent a promising source for reproductive applications. This study aimed to examine the ability of human TSCs to differentiate into primordial germ cell-like cells (PGC-like cells) and to identify candidate molecular markers associated with this process. Human ovarian tissues were collected and small antral follicles were isolated for TSC extraction. Following stemness validation using bulk RNA sequencing, TSCs were cultured under optimized conditions for 45 days to induce PGC-like differentiation. To identify potential PGC markers, early human PGC single-cell RNA-seq datasets were analyzed and refined by excluding genes expressed in TSCs. Differentiation of TSCs into PGC-like cells was confirmed morphologically and at the transcript level. Transcriptomic filtering identified GTSF1, L1TD1, TCL1A, and TCL1B as potential PGC markers. Gene expression analyses demonstrated significant upregulation of GTSF1 and L1TD1 in differentiated cells. Overall, our findings demonstrate that human TSCs can generate PGC-like cells in vitro, and suggest that GTSF1, together with L1TD1, may serve as promising molecular markers for monitoring the progression of this differentiation process.