Association of 17β-HSD3 with steroidogenesis-related gene expression and primordial germ cell development in ducks

This study aimed to investigate the potential role of 17β-hydroxysteroid dehydrogenase 3 (17β-HSD3) in steroidogenesis and its possible involvement in germ cell development and meiotic initiation in ducks. Primordial germ cells (PGCs) were isolated from duck embryos and characterized by epithelioid adherent morphology, with more than 90% of cells showing positive expression of c-kit. Functional analyses indicated that overexpression of 17β-HSD3 was associated with increased PGC proliferation (48 h, P < 0.05; 72 h, P < 0.01) and reduced apoptosis (P < 0.0001). In addition, 17β-HSD3 overexpression was correlated with a numerical increase in AKR1D1 expression (P > 0.05) and a significant decrease in P450scc expression (P < 0.001). Retinoic acid (RA) treatment (0.25-1 μM) showed a tendency toward cell cycle progression, as reflected by a decrease in the G0/G1 phase population and an increase in S phase cells, although these changes did not reach statistical significance (P > 0.05). Furthermore, RA exposure was significantly associated with increased expression of 17β-HSD3, Cvh, and Stra8, and decreased expression of pluripotency-associated genes Itga6 and Sox2 (P < 0.001 or P < 0.0001), suggesting molecular changes consistent with meiotic entry. Collectively, these results suggest that 17β-HSD3 may be involved in the modulation of steroidogenesis-related gene expression in duck germ cells and is associated with germ cell proliferation and meiotic initiation. This study provides preliminary evidence that may contribute to the understanding of molecular mechanisms underlying avian germ cell development and reproductive regulation in poultry.