Circadian miR-218-5p targets gene CA2 to regulate uterine carbonic anhydrase activity during egg shell calcification

Gga-miR-34b-3p targets calbindin 1 to regulate cellular calcium ion homeostasis during eggshell calcification in chicken uterus

Improving eggshell quality in poultry is a key breeding goal, and identifying genetic markers that regulate eggshell calcification is essential for accelerating genetic advancements. This study focused on identifying the keys genes and molecular mechanisms that regulate eggshell calcification in the chicken uterus. The results showed that rapid eggshell mineralization began approximately 4 h after the egg enters the uterus, corresponding with observed morphological and histological changes in the uterine tissue. This is associated with increased energy demands and the production of ion transport proteins. Transcriptome analysis identified calbindin-1 (CALB1), ATPase plasma membrane Ca2+ transporting 2 (ATP2B2), and gga-miR-34b-3p as differentially expressed during eggshell formation. CALB1 and ATP2B2 were predicted targets of gga-miR-34b-3p, with roles in maintaining cellular calcium ion balance. A dual-luciferase reporter assay confirmed that gga-miR-34b-3p directly targeted inhibited CALB1 expression, although no significant changes in the luciferase activity were observed with the co-transfection of ATP2B2 wild-type and gga-miR-34b-3p mimic. Validation experiments showed significant increases in CALB1 and ATP2B2 mRNA and protein levels of CALB1 and ATP2B2 in the chicken uterus during eggshell calcification, with CALB1 predominantly expressed in the cytoplasm of uterine tubular gland cells. Furthermore, primary uterine tubular gland cells, identified using immunofluorescence for Cytokertin 18, demonstrated that silencing CALB1 and ATP2B2 increased intracellular Ca2+ concentration in these cells. Taken together, these findings suggest that the gga-miR-34b-3p/CALB1 regulatory axis maintains calcium ion homeostasis in the uterine tubular gland cells, to facilitate continuous and efficient eggshell calcification and thereby enhancing eggshell quality in chickens.

Integrating Single-Cell RNA-Seq and ATAC-Seq Analysis Reveals Uterine Cell Heterogeneity and Regulatory Networks Linked to Pimpled Eggs in Chickens

Pimpled eggs have defective shells, which severely impacts hatching rates and transportation safety. In this study, we constructed single-cell resolution transcriptomic and chromatin accessibility maps from uterine tissues of chickens using single-cell RNA sequencing (scRNA-seq) and single-cell ATAC sequencing (scATAC-seq). We identified 11 major cell types and characterized their marker genes, along with specific transcription factors (TFs) that determine cell fate. CellChat analysis showed that fibroblasts had the most extensive intercellular communication network and that the chickens laying pimpled eggs had amplified immune-related signaling pathways. Differential expression and enrichment analyses indicated that inflammation in pimpled egg-laying chickens may lead to disruptions in their circadian rhythm and changes in the expression of ion transport-related genes, which negatively impacts eggshell quality. We then integrated TF analysis to construct a regulatory network involving TF-target gene-Gene Ontology associations related to pimpled eggs. We found that the transcription factors ATF3, ATF4, JUN, and FOS regulate uterine activities upstream, while the downregulation of ion pumps and genes associated with metal ion binding directly promotes the formation of pimpled eggs. Finally, by integrating the results of scRNA-seq and scATAC-seq, we identified a rare cell type-ionocytes. Our study constructed single-cell resolution transcriptomic and chromatin accessibility maps of chicken uterine tissue and explored the molecular regulatory mechanisms underlying pimpled egg formation. Our findings provide deeper insights into the structure and function of the chicken uterus, as well as the molecular mechanisms of eggshell formation.

Genome-wide re-sequencing reveals selection signatures for important economic traits in Taihang chickens

Taihang chickens is precious genetic resource with excellent adaptability and disease resistance, as well as high-quality eggs and meat. However, the genetic mechanism underlying important economic traits remain largely unknown. To address this gap, we conducted whole-genome resequencing of 66 Taihang and 15 White Plymouth rock chicken (Baiyu). The population structure analysis revealed that Taihang chickens and Baiyu are 2 independent populations. The genomic regions with strong selection signals and some candidate genes related to economic and appearance traits were identified. Additionally, we found a continuously selected 1.2 Mb region on chromosome 2 that is closely related to disease resistance. Therefore, our findings were helpful in further understanding the genetic architecture of the Taihang chickens and provided a worthy theoretical basis and technological support to improve high-quality Taihang chickens.

Whole transcriptome sequencing reveals key genes and ceRNA regulatory networks associated with pimpled eggs in hens

Eggshell is one of the most important indicators of egg quality, and due to low shell strength, pimple eggs (PE) are more susceptible to breakage, thus causing huge economic losses to the egg industry. At the current time, the molecular mechanisms that regulate the formation of pimple eggs are poorly understood. In this study, uterine tissues of PE-laying hens (n = 8) and normal egg (NE) -laying hens (n = 8) were analyzed by whole transcriptome sequencing, and a total of 619 differentially expressed mRNAs (DE mRNAs), 122 differentially expressed lncRNAs (DE lncRNAs) and 21 differentially expressed miRNAs (DE miRNAs) were obtained. Based on the targeting relationship among DE mRNAs, DE lncRNAs and DE miRNAs, we constructed a competitive endogenous RNA (ceRNA) network including 12 DE miRNAs, 19 DE lncRNAs, and 128 DE mRNAs. Considering the large amount of information contained in the network, we constructed a smaller ceRNA network to better understand the complex mechanisms of pimple egg formation. The smaller ceRNA network network contains 7 DE lncRNAs (LOC107056551, LOC121109367, LOC121108909, LOC121108862, LOC112530033, LOC121113165, LOC107054145), 5 DE miRNAs (gga-miR-6568-3p, gga-miR-31-5p, gga-miR-18b-3p, gga-miR-1759-3p, gga-miR-12240-3p) and 7 DE mRNAs (CABP1, DNAJC5, HCN3, HPCA, IBSP, KCNT1, OTOP3), and these differentially expressed genes may play key regulatory roles in the formation of pimpled eggs in hens. This study provides the overall expression profiles of mRNAs, lncRNAs and miRNAs in the uterine tissues of hens, which provides a theoretical basis for further research on the molecular mechanisms of pimpled egg formation, and has potential applications in improving eggshell quality.

Circular RNA circRPS19 promotes chicken granulosa cell proliferation and steroid hormone synthesis by interrupting the miR-218-5p/INHBB axis

Ovarian follicle development is an important physiological activity for females and makes great significance in maintaining female health and reproduction performance. The development of ovarian follicle is mainly affected by the granulosa cells (GCs), whose growth is regulated by a variety of factors. Here, we identified a novel circular RNA (circRNA) derived from the Ribosomal protein S19 (RPS19) gene, named circRPS19, which is differentially expressed during chicken ovarian follicle development. Further explorations identified that circRPS19 promotes GCs proliferation and steroid hormone synthesis. Furthermore, circRPS19 was found to target and regulate miR-218-5p through a competitive manner with endogenous RNA (ceRNA). Functionals investigation revealed that miR-218-5p attenuates GCs proliferation and steroidogenesis, which is opposite to that of circRPS19. In addition, we also confirmed that circRPS19 upregulates the expression of Inhibin beta B subunit (INHBB) by binding with miR-218-5p to facilitate GCs proliferation and steroidogenesis. Overall, this study revealed that circRPS19 regulates GCs development by releasing the repression of miR-218-5p on INHBB, which suggests a novel mechanism in respect to circRNA and miRNA regulation in ovarian follicle development.

Whey Protein Hydrolysate Exerts Anti-Inflammatory Effects to Alleviate Dextran Sodium Sulfate (DSS)-Induced Colitis via Microbiome Restoration

Whey protein hydrolysate (WPH) has been shown to have a variety of bioactivities. This study aimed to investigate the preventive effect of WPH on dextran sodium sulfate (DSS)-induced colitis in C57BL/6J mice. The results indicated that WPH intervention for 37 days was effective in delaying the development of colonic inflammation, and high doses of WPH significantly inhibited weight loss (9.16%, n = 8, p < 0.05), protected the colonic mucosal layer, and significantly reduced the levels of inflammatory factors TNF-α, IL-6, and IL-1β in mice with colitis (n = 8, p < 0.05). In addition, WPH intervention was able to up-regulate the short-chain fatty acids secretion and restore the gut microbiome imbalance in mice with colitis. Notably, high-dose WPH intervention increased the relative abundance of norank_f_Muribaculaceae by 1.52-fold and decreased the relative abundance of Romboutsia and Enterobacter by 3.77-fold and 2.45-fold, respectively, compared with the Model group. WPH intervention protected colitis mice mainly by reversing the microbiome imbalance and regulating the major histocompatibility complex (MHC) class I pathway. This study showed that WPH has anti-inflammatory activity and a promising colitis management future.