Comparison of Sertoli cells in duck testes pre- and post-sexual maturation.

To investigate the role of Sertoli cells in duck testicular development and maturation, we conducted single-cell RNA sequencing on testes from immature (IMT) and mature (MT) ducks. Sertoli cells accounted for 27.75 % and 33.42 % of testicular cells in IMT and MT, respectively. We identified 2,630 differentially expressed genes (DEGs) in mature Sertoli cells, with 1,540 upregulated and 1,090 downregulated. Subtype analysis revealed 2,498 DEGs in Sertoli cell type 1 (SC1) (898 up, 1,600 down) and 2,515 DEGs in SC2 (1,291 up, 1,224 down), including 1,090 SC1-specific, 1,107 SC2-specific, and 1,408 shared genes. Gene Ontology analysis showed DEGs were mainly linked to cellular components: SC1 DEGs were enriched in intracellular structures (e.g., nucleus), whereas SC2 DEGs were enriched in membrane- and extracellular-related components (e.g., cell periphery). KEGG pathway analysis highlighted significant enrichment of "Spliceosome," "Neurotrophin signaling," and "MAPK signaling" pathways in MT and IMT, with Neurotrophin signaling predominant in SC1 and MAPK signaling in SC2. Furthermore, the Notch signaling pathway was significantly enriched for SC1-specific genes, whereas the MAPK signaling pathway was significantly enriched for SC2-specific genes. Protein-protein interaction analysis of these pathways identified core genes, including SF3A2, SNRPF, SNRPB2, SNRPG, SF3B4, MAP3K1, NRAS, MET, and EGF. This study delineates developmental dynamics of duck Sertoli cells and offers preliminary insights into regulatory mechanisms underlying testicular maturation, providing a key theoretical and data-driven foundation for understanding Sertoli cell functions in avian testis development.