Human primordial germ cell heterogeneity in vitro is associated with distinctive biological states

BACKGROUND: Primordial germ cells (PGCs) exhibit molecular heterogeneity during development, yet whether this reflects functionally distinct states remains unclear. METHODS: We investigated the functional significance of DND1 translation heterogeneity in human PGC-like cell (hPGCLC) extended culture, using dual fluorescent reporters, transcriptomic analysis and functional assays. RESULTS: Single-cell RNA-sequencing revealed that DND1 + hPGCLCs are enriched in RNA regulatory genes including those associated with P-bodies and translational control. DND1 + cells exhibit reduced proliferation, cell cycle exit, and elevated nuclear expression P27 (CDKN1B). These cells also maintained stable expression of genes essential for germ cell differentiation. Notably, BMP2 supplementation stabilized DND1 translation without altering mRNA levels or proliferation rates. CONCLUSIONS: Together, these findings demonstrate that post-transcriptional regulation by DND1 coordinates cell cycle dynamics with distinct cellular state in human germ cells, highlighting critical translational control mechanisms in germline development.