The Smyth line (SL) of chicken is an excellent animal model for human autoimmune vitiligo. In SL vitiligo (SLV) post-natal loss of melanocytes in feathers appears to be due to cell-mediated immunity. In this study, leukocyte-infiltration and associated expression (RNA) of immune function-related cytokines in growing feathers were investigated throughout SLV-development and -progression. Both leukocyte infiltration and cytokine expression levels started to increase near visible SLV onset (early SLV), reached peak levels during active SLV, and decreased to near pre-vitiligo levels after complete loss of melanocytes. Specifically, significant increases were noticed in relative proportions of T cells, B cells, and MHC II-expressing cells during active SLV. Levels of T cell infiltration were higher than those of B cells, with more CD8+ than CD4+ cells throughout SLV. Elevated leukocyte infiltration in early and active SLV was accompanied by increased levels of cytokine expression, especially in interferon-gamma, interleukin (IL)-10 and IL-21. Low expression of IL-4 and IL-17 did not suggest important roles of Th2 and Th17 cells in SLV pathogenesis. Taken together, SLV appears to be a Th1 polarized autoimmune disease, whereby interferon-gamma expression is strongly associated with parallel increases in IL-10 and IL-21, particularly during early and active stages of SLV.

BackgroundThe Smyth line (SL) of chicken is an excellent avian model for human autoimmune vitiligo. The etiology of vitiligo is complicated and far from clear. In order to better understand critical components leading to vitiligo development, cDNA microarray technology was used to compare gene expression profiles in the target tissue (the growing feather) of SL chickens at different vitiligo (SLV) states.ResultsCompared to the reference sample, which was from Brown line chickens (the parental control), 395, 522, 524 and 526 out of the 44 k genes were differentially expressed (DE) (P ≤ 0.05) in feather samples collected from SL chickens that never developed SLV (NV), from SLV chickens prior to SLV onset (EV), during active loss of pigmentation (AV), and after complete loss of melanocytes (CV). Comparisons of gene expression levels within SL samples (NV, EV, AV and CV) revealed 206 DE genes, which could be categorized into immune system-, melanocyte-, stress-, and apoptosis-related genes based on the biological functions of their corresponding proteins. The autoimmune nature of SLV was supported by predominant presence of immune system related DE genes and their remarkably elevated expression in AV samples compared to NV, EV and/or CV samples. Melanocyte loss was confirmed by decreased expression of genes for melanocyte related proteins in AV and CV samples compared to NV and EV samples. In addition, SLV development was also accompanied by altered expression of genes associated with disturbed redox status and apoptosis. Ingenuity Pathway Analysis of DE genes provided functional interpretations involving but not limited to innate and adaptive immune response, oxidative stress and cell death.ConclusionsThe microarray results provided comprehensive information at the transcriptome level supporting the multifactorial etiology of vitiligo, where together with apparent inflammatory/innate immune activity and oxidative stress, the adaptive immune response plays a predominant role in melanocyte loss.

Avian sperm storage tubules ( SSTs ), which are located in the uterovaginal junction ( UVJ ) of the oviduct, are primary sperm storage sites after mating or artificial insemination. The mechanism underlying reduced sperm storage efficiency of SSTs which is highly correlated with decreased fertility rates in aged laying breeders remains largely unclear. Here, comparative transcriptomic analysis between the aged and young White Leghorn hens (120 vs. 30 wk) was applied to identify gene expression changes of UVJs containing SSTs. Bioinformatics analysis revealed 567 upregulated and 1998 downregulated differentially expressed genes. Gene ontology analysis was highly enriched in terms of immune system, cell adhesion, and cytoskeleton proteins. Kyoto Encyclopedia of Genes and Genomes analysis revealed 5 significant ( P < 0.05) pathways including inositol phosphate and glycerophospholipid metabolism. β-Galactosidase staining of chicken UVJ sections suggested increased cell senescence via aging. Oil Red O staining and immunohistochemistry detection of ADFP both confirmed distribution of lipid droplets in SST cells with increased intensity in aged breeders. The lipid synthesis and metabolism-related genes represented by TFAP2 and PLD1 were differentially expressed in aged laying breeders. The upregulation of IL15 and downregulation of a large number of immune-related genes in aged breeders indicate altered immune homeostasis in UVJs and SSTs. The increased accumulation of lipids, and altered immunity homeostasis, combined with other factors ( TJP1 , MYL9 , AFDN , and RPL13 , etc.) are potentially dominant effectors to decrease the sperm storage efficiency and egg fertility in aged laying breeders.

In birds, the sperm storage tubules ( SST ) are dispersed in uterovaginal junction ( UVJ ) and highly correlated with differential capacity of sperm storage ( SS ) in and among species with unspecified mechanisms. Here, the SS duration of 252 egg layer breeders was evaluated in 5 rounds with 3 phenotypic traits to screen high- and low-SS individuals, respectively, followed with transcriptome of UVJ tissues and metabolome of serum (high-SS vs. low-SS) to decipher the candidate genes and biochemical markers correlated with differential SS capacity. Histological characterization suggested slightly higher density of SST in UVJ (high-SS vs. low-SS). Transcriptome analyses identified 596 differentially expressed genes (336 upregulated vs. 260 downregulated), which were mainly enriched in gene ontology terms of homeostasis, steroid and lipid metabolism and hormone activity, and 12 significant pathways ( P < 0.05) represented by calcium, steroid, and lipid metabolism. Immunohistochemical staining of GNAQ, ST6GAL1, ADFP, and PCNA showed similar distribution in UVJ tissues between 2 groups. Several candidates ( HSD11B2 , DIO2 , AQP3 , GNAQ, NANS, ST6GAL1 ) combined with 4 (11β-prostaglandin F2α, prostaglandin B1, 7α-hydroxytestosterone, and N-acetylneuraminic acid) of 40 differential metabolites enriched in serum metabolome were considered as regulators and biomarkers of SS duration in egg layer breeders. The integrated transcriptome and metabolome analyses of chicken breeder hens will provide novel insights for exploration and improvement of differential SS capacity in birds.

The Smyth line (SL) chicken is an animal model for autoimmune vitiligo (SLV). SL chickens develop spontaneous, post-hatch, autoimmune melanocyte loss in growing feathers (GF). With repeatable access to GF and the high incidence (85-95%) of SLV, SLV development can be examined in the same bird. A microarray study was conducted to investigate the global transcriptomic profile in GF from SL and Brown line (BL, parental control) chickens. RNA pools were made from GF of BL chickens, SL chickens that never developed SLV (S0), and SL chickens before (S1), during (S2) and at complete (S3) SLV. Complementary RNA probes were generated from BL and SL (S0~S3) RNA, labeled with Cy3 and Cy5, respectively and hybridized on a chicken 4x44 K Agilent microarray. The slide was scanned and normalized signal intensities were analyzed to identify differentially expressed (DE, &gt;2x) genes between BL and SL samples. There were 504, 518, 1124, and 1151 DE genes containing 262, 226, 658, and 680 unique DE genes in S0, S1, S2 and S3, respectively. S0 and S1 had similar proportions of up-and down-regulated DE genes while up-regulated DE genes predominated in S2 and S3. The highest expressed DE genes were related to immune activity and cell death. Ingenuity Pathway Analysis software was used to determine biological functions and pathways of DE genes. The study provides comprehensive information from global gene expression to functionalities and biological networks of DE genes in the process of SLV.