Wnt/β-catenin activation in response to STAT3 inhibition is required for embryonic feather follicle development in Jilin white geese ( Anser cygnoides )

The correct development of follicles is essential for feather quality in geese, yet the role of STAT3 in feather follicle formation during geese embryogenesis remains unclear.2. In this study, 140 Jilin White Goose (Anser cygnoides) embryos were used as the experimental subjects. Feather follicle morphology at different developmental stages was examined using H&E staining and STAT3 expression was assessed by RT-qPCR and Western blotting. Building on these observations, an in ovo injection experiment was performed at embryo day (ED)18 and an ex vivo skin-culture system was established at ED23.3. The STAT3 gene expression peaked at ED23, coinciding with a critical phase of feather follicle structural maturation. Following Stattic treatment, both STAT3 and phosphorylated STAT3 (p-STAT3) levels were markedly reduced, whereas the Wnt/β-catenin signalling genes β-cateninand LEF1 were up-regulated. This suggested that STAT3 may function as a negative regulator of this pathway.4. The ex vivo culture assay showed increased expression of PCNA and Bcl-2 and reduced Caspase-3. This showed that STAT3 gene inhibition promotes cell proliferation and suppresses apoptosis. These findings supported a regulatory role of STAT3 in feather follicle development.5. The STAT3 gene serves as an important regulatory factor in feather follicle formation during goose embryonic development.