Expression of FOXO3 in the skin follicles of goose embryos during embryonic development

1. The Forkhead box O3 (FOXO3) transcription factor is a crucial regulator in controlling cell metabolism, proliferation, apoptosis, migration and response to oxidative stress. However, FOXO3 has not previously been studied much in the embryonic skin follicles of geese.2. This study used Zhedong white geese (Anser cygnoides), Jilin white geese (Anser cygnoides) and Hungarian white geese (Anser anser). The feather follicle structure in the dorsal skin during embryonic stages was examined with haematoxylin and eosin (HE) and Pollak staining. The FOXO3 protein content in the embryonic dorsal skin from feather follicles was detected using western blotting and quantitative real-time PCR.3. The mRNA expression level of FOXO3 in the dorsal skin of Jilin white geese was highly expressed on embryonic day 23 (E23; P < 0.01), while mRNA expression of FOXO3 was highly expressed in the feather follicle of Hungarian white geese at E28 (P < 0.01). The expression of FOXO3 protein mainly concentrated in the early embryonic phase among these goose breeds (P < 0.05). This suggested that FOXO3 plays a crucial role in the development and growth of embryonic dorsal skin of feather follicles. The location of the FOXO3 protein was determined using the IHC technique, which further verified the effect of FOXO3 in the dorsal skin for feather follicles during embryogenesis.4. The study demonstrated the differential expression and localisation of the FOXO3 gene among different goose species. It was speculated that the gene could potentially improve goose feather follicle development and feather-related traits and provide a basis for further understanding of FOXO3 function in the dorsal tissue of goose embryos.

Regulation of feather follicle development and Msx2 gene SNP degradation in Hungarian white goose

BACKGROUND

Hungarian white goose has excellent down production performance and was introduced to China in 2010. The growth and development of feather follicles has an important impact on down production. Goose feather follicles can be divided into primary and secondary feather follicles, both of which originate in the embryonic stage. Msx2 (Msh Homeobox 2) plays a regulatory role in tissues and organs such as eyes, teeth, bones and skin. However, its regulatory mechanism on goose feather follicles development remains unclear.

RESULTS

Msx2 gene first increased, then decreased and increased at the end (E13, E18, E23, E28) during embryonic feather follicle development, and the expression level was the highest at E18. The pEGFP-N1-Msx2 overexpression vector and si-Msx2 siRNA vector were constructed to transfect goose embryo dermal fibroblasts. The results showed that the cell viability of ov-Msx2 group was significantly increased, and the gene expression levels of FGF5 and TGF-β1 genes were significantly down-regulated (P < 0.05), the expressions of PCNA, Bcl2, CDK1, FOXN1 and KGF genes were significantly up-regulated (P < 0.05). After transfection of siRNA vector, the cell viability of the si-Msx2 group was significantly decreased (P < 0.01) compared with the si-NC group. TGF-β1 expression was significantly up-regulated (P < 0.05), FGF5 expression was extremely significantly up-regulated (P < 0.01), while PCNA, Bcl2, CDK1, FOXN1 and KGF gene expression was significantly down-regulated (P < 0.05). High-throughput sequencing technology was used to mine the exon SNPs of Msx2. A total of 11 SNP loci were screened, four of the SNPs located in exon 1 were missense mutations. The feather follicle diameter of the GC genotype at the G78C site is significantly larger than that of the other two genotypes.

CONCLUSIONS

Msx2 maybe inhibit the apoptosis of goose dermal fibroblasts and promotes their proliferation. G78C can be used as a potential molecular marker for downy Variety.

The co-administration of live fowlpox and Newcastle disease vaccines by non-invasive routes to chickens reared by smallholders in Tanzania and Nepal

The co-administration of commercial live fowlpox (FP) and Newcastle disease (ND) vaccines when given by non-invasive (needle-free) routes was demonstrated to be safe and to elicit immunity in two field studies, one in Tanzania the other in Nepal. Both studies were of a cluster-randomised controlled design in which birds were randomly assigned to one of five treatment groups: (i) administration with FP vaccine alone (feather follicle), (ii) administration with ND vaccine alone (eye-drop), (iii) concurrent administration of FP (feather follicle) and ND (eye-drop) vaccines, (iv) concurrent administration of FP (wing-web) and ND (eye-drop) vaccines, and (v) unvaccinated, acting as environmental sentinels. Data from a total of 1167 birds from seven villages in Hanang District of Tanzania together with 1037 birds from eleven villages in Dhading District of Nepal were collected over a period of 21 and 28 days, respectively. Immune responses to FP vaccination were evaluated by local take reactions, while those to ND vaccination were evaluated serologically by haemagglutination inhibition test. The two studies demonstrated that the concurrent vaccination of free-range, indigenous breeds of chicken with live FP and ND vaccines, both administered by non-invasive routes, was safe and induced immunity against FP and ND that were non-inferior to the administration of FP and ND vaccines alone. These findings are important to appropriately trained small-scale backyard poultry farmers as well as to paraprofessionals and community health workers helping to increase vaccine uptake and the control of both FP and ND in low- to middle-income countries.

Revealing the impacts on shaping scutate scales in goose skin

Feather follicles and scales are two types of skin appendages distributed on different parts of avian skin. The morphogenesis and development of scales in waterfowl remain largely unknown. Here, we used H&E staining, ISH and RNA sequencing to reveal the morphological and molecular variations at the early development of scutate scales in goose shank skin. Transcriptome analysis produced 1824 differentially expressed genes (DEGs) regulating the induction of scales and further enriched gene function in cell adhesion and Wnt signaling pathway, etc. A total of 8 candidate genes (ALDOC, CSRP2, KRT15, KRT75, LGALS1, S100A6, OGN and SFRP2) were further detected by RT-qPCR to show upregulated (6 genes) and downregulated (2 genes) from pre-placodal to placode stage during the induction of goose scales. The localization of 7 candidate genes (ALDOC, CSRP2, CD109, KRT15, KRT75, S100A6, and OGN) by ISH suggests the potential roles for dermal and epidermal development during the induction of scutate scales. The dynamic molecular changes and specific gene expression patterns revealed in this report provide general knowledge of scale development in waterfowl as well as skin appendage diversity.

Expression patterns of three JAK-STAT pathway genes in feather follicle development during chicken embryogenesis

The Janus kinase (JAK)-signal transducer and activator of transcription (STAT) (JAK-STAT) pathway is shown to restrain the hair follicles in catagen and telogen and prevent anagen reentry in murine hair follicle cycling. The early roles of JAK-STAT pathway genes in skin development remain uncharacterized in mouse and chicken models. Here, we revealed the expression patterns of three JAK-STAT pathway genes (JAK1, JAK2, and TYK2) in chicken embryonic skin at E6-E10 stages which are key to feather follicle morphogenesis. Multiple sequence alignment of the three genes from chicken and other species all showed a closely related homology with birds like quail and goose. Whole mount in situ hybridization (WISH) revealed weak expression of JAK1, JAK2, and TYK2 in chicken skin at E6 and E7, and followed with the focally restricted signals in the feather follicles of neck and body skin located dorsally at E8 for JAK1, E9 for TYK2 and E10 for JAK2 gene. All three genes displayed stronger expression in feather follicles of neck skin than that of body skin. The expression levels of JAK1 and TYK2 were much stronger than those of JAK2. Quantitative real-time PCR (qRT-PCR) analysis revealed the increased expression tendency for JAK2 both in the neck and body skin from E6 to E10, and the much stronger expression in neck and body skin at later stages (E8-E10) than earlier stages (E6 and E7) for JAK1 and TYK2. Overall, these findings suggest that JAK1 and TYK2, not JAK2 are important to specify the feather follicle primordia, and to arrange the proximal-distal axis of feather follicles, respectively, during the morphogenesis of feather follicles in embryonic chicken skin.

Dkk2/Frzb in the dermal papillae regulates feather regeneration

Avian feathers have robust growth and regeneration capability. To evaluate the contribution of signaling molecules and pathways in these processes, we profiled gene expression in the feather follicle using an absolute quantification approach. We identified hundreds of genes that mark specific components of the feather follicle: the dermal papillae (DP) which controls feather regeneration and axis formation, the pulp mesenchyme (Pp) which is derived from DP cells and nourishes the feather follicle, and the ramogenic zone epithelium (Erz) where a feather starts to branch. The feather DP is enriched in BMP/TGF-β signaling molecules and inhibitors for Wnt signaling including Dkk2/Frzb. Wnt ligands are mainly expressed in the feather epithelium and pulp. We find that while Wnt signaling is required for the maintenance of DP marker gene expression and feather regeneration, excessive Wnt signaling delays regeneration and reduces pulp formation. Manipulating Dkk2/Frzb expression by lentiviral-mediated overexpression, shRNA-knockdown, or by antibody neutralization resulted in dual feather axes formation. Our results suggest that the Wnt signaling in the proximal feather follicle is fine-tuned to accommodate feather regeneration and axis formation.