The pituitary gland directly regulates the reproduction of domestic animals. Research has increasingly focused on the potential regulatory mechanism of non-coding RNA in pituitary development. Little is known about the differential expression pattern of lncRNAs in Hu sheep, a famous sheep breed with high fecundity, and its role in the pituitary gland between the follicular phase and luteal phase. Herein, to identify the transcriptomic differences of the sheep pituitary gland during the estrus cycle, RNA sequencing (RNA-Seq) was performed. The results showed that 3529 lncRNAs and 16,651 mRNAs were identified in the pituitary gland. Among of them, 144 differentially expressed (DE) lncRNA transcripts and 557 DE mRNA transcripts were screened in the follicular and luteal phases. Moreover, GO and KEGG analyses demonstrated that 39 downregulated and 22 upregulated genes interacted with pituitary functions and reproduction. Lastly, the interaction of the candidate lncRNA XR_001039544.4 and its targeted gene LHB were validated in sheep pituitary cells in vitro. LncRNA XR_001039544.4 and LHB showed high expression levels in the luteal phase in Hu sheep. LncRNA XR_001039544.4 is mainly located in the cytoplasm, as determined by FISH analysis, indicating that XR_001039544.4 might act as competing endogenous RNAs for miRNAs to regulate LHB. LncRNA XR_001039544.4 knockdown significantly inhibited LH secretion and cell proliferation. LncRNA XR_001039544.4 may regulate the secretion of LH in the luteal-phase pituitary gland via affecting cell proliferation. Taken together, these findings provided genome-wide lncRNA- and mRNA-expression profiles for the sheep pituitary gland between the follicular and luteal phases, thereby contributing to the elucidation of the molecular mechanisms of pituitary function.

Iron overload is a common complication in various chronic liver diseases, including non-alcoholic fatty liver disease (NAFLD). Lipid and bile acid metabolism disorders are regarded as crucial hallmarks of NAFLD. However, effects of iron accumulation on lipid and bile acid metabolism are not well understood. Ferulic acid (FA) can chelate iron and regulate lipid and bile acid metabolism, but its potential to alleviate lipid and bile acid metabolism disorders caused by iron overload remains unclear. Here, in vitro experiments, iron overload induced oxidative stress, apoptosis, genomic instability, and lipid deposition in AML12 cells. FA reduced lipid and bile acid synthesis while increasing fatty acid β-oxidation and bile acid export, as indicated by increased mRNA expression of PPARα, Acox1, Adipoq, Bsep, and Shp, and decreased mRNA expression of Fasn, Acc, and Cyp7a1. In vivo experiments, FA mitigated liver injury in mice caused by iron overload, as indicated by reduced AST and ALT activities, and decreased iron levels in both serum and liver. RNA-seq results showed that differentially expressed genes were enriched in biological processes related to lipid metabolism, lipid biosynthesis, lipid storage, and transport. Furthermore, FA decreased cholesterol and bile acid contents, downregulated lipogenesis protein FASN, and bile acid synthesis protein CYP7A1. In conclusion, FA can protect the liver from lipid and bile acid metabolism disorders caused by iron overload by targeting FASN and CYP7A1. Consequently, FA, as a dietary supplement, can potentially prevent and treat chronic liver diseases related to iron overload by regulating lipid and bile acid metabolism.

Pituitary gonadotropins play a pivotal role in reproduction. Long noncoding RNAs (lncRNAs) have been identified as important regulators in the hypothalamic–pituitary–ovarian (HPO) axis associated with reproduction. However, the contributions of lncRNAs to pituitary gonadotropin secretion remain largely unknown. Therefore, this work was performed to uncover the functional mechanisms of the novel lncRNA TCONS_00083279 (lncRNA SM2) and its potential targeting pathway oar-miR-16b/TGF-beta/SMAD2, which is associated with gonadotropin secretion in sheep pituitary cells. In the present study, the lncRNA SM2 showed high expression levels in the sheep pituitary gland, and it was located in both the nucleus and the cytoplasm of pituitary cells. lncRNA SM2 knockdown inhibited pituitary cell proliferation and FSH and LH secretion. The function of the lncRNA SM2 was sponged by oar-miR-16b, and this regulated the growth and gonadotropin secretion of pituitary cells by modulating SMAD2, as shown by the dual-luciferase reporter assay. FSH and LH levels were both upregulated by SMAD2 overexpression. Moreover, the levels of the lncRNA SM2, SMAD2 and TGFR1, as well as FSH and LH, in sheep pituitary cells increased significantly under gonadotropin-releasing hormone (GnRH) stimulation (p < 0.05). This work illustrates that the lncRNA SM2 regulates gonadotropin secretion in the Hu sheep anterior pituitary by targeting the oar-miR-16b/TGF-β/SMAD2 signaling pathway, providing a valuable resource for understanding the molecular mechanisms underlying sheep reproduction.

Placental development plays a pivotal role in ensuring successful pregnancy outcomes, yet its molecular regulatory mechanisms in sheep remain poorly characterized. This study aimed to systematically investigate stage-specific proteomic dynamics and functional adaptations in ovine placental tissues across gestation to elucidate molecular drivers of placental maturation. Using data-independent acquisition proteomics, we identified 7774 proteins in Hu sheep placental tissues at gestational days 50, 80, and 120. Comparative analysis revealed 1450, 1026, and 1964 differentially expressed proteins (DEPs) in the 50 d vs. 80 d, 80 d vs. 120 d, and 50 d vs. 120 d comparisons, respectively. DEPs were functionally enriched in biological processes including cell proliferation, apoptosis, angiogenesis, nutrient transport, and steroid synthesis, with prominent involvement of the PI3K-Akt, MAPK, and estrogen signaling pathways. Protein interaction networks identified SRC, MAP3K1, KRAS, and TJP1 as central regulators exhibiting dynamic expression patterns across gestation. Temporal expression trends showed progressive upregulation of tight junction, immune response, and glucose metabolism proteins, contrasting with downregulation of endoplasmic reticulum protein processing and proteasome components. Validation experiments confirmed elevated proliferation/transport gene expression at 80 d versus 50 d, followed by increased apoptosis/transport genes and decreased proliferation markers at 120 d. This comprehensive proteomic profiling reveals stage-specific regulatory networks governing placental development in sheep, highlighting coordinated shifts in proliferative, metabolic, and structural remodeling processes. These findings advance our understanding of placental adaptation mechanisms and provide valuable insights for improving reproductive management in livestock species.

Endometrial stromal cell (ESC) plasticity is critical to embryo survival and conceptus elongation; however, their genetic regulation remains unclear. To elucidate the molecular mechanisms by which ESR1 regulates sheep fecundity through endometrial function, we investigated the effects of ESR1 on ovine ESCs in vitro. Tissue distribution analysis revealed elevated ESR1 expression in the reproductive organs, particularly the endometrium, compared with that in non-reproductive tissues. Both ESR1 mRNA and its encoded ERα protein were significantly upregulated in the endometrium of high-fecundity Hu sheep compared to those in the endometrium of low-fecundity Hu sheep. Given the specific localisation of ERα in ESCs, we examined the functional roles of ESR1 in these cells in vitro. ESR1 knockdown in ESCs inhibited cell proliferation and induced apoptosis, concomitant with increased Caspase3 and Caspase9 mRNA expression. Furthermore, ESR1 interference triggered G0/G1-phase cell cycle arrest via the upregulation of P53 and P21 and significantly impaired cell migration capacity. Collectively, these results demonstrate that ESR1 critically regulates ESC proliferation, apoptosis, cell cycle progression, and migration. Our findings establish ESR1 as a key determinant of sheep fecundity and provide mechanistic insights into the high reproductive efficiency of Hu sheep.