Prostaglandin E₂ (PGE₂) has been implicated in multiple biological processes during pregnancy in ruminants. However, the regulatory effects of PGE₂ on endometrial function during the diestrus period and its underlying molecular mechanisms remain poorly understood. Herein, PGE₂ treatment promoted the accumulation of lipid droplets and induced cytoskeletal reorganization in bEECs. As a well-established inducer of lipid droplet formation, oleic acid (OA) treatment significantly increased the number of lipid droplets in bEECs, altered the distribution of F-actin and disrupted the expression patterns of key adhesion-related proteins. Transcriptomic analysis revealed that the PPAR signaling pathway was the key pathway that responded to PGE₂ treatment in bEECs, and its downstream target gene FABP3 was markedly up-regulated. Knockdown of FABP3 led to a reduced number of BTC spheroids and down-regulation of adhesion-related proteins in bEECs while increasing the density of microvilli and up-regulating the expression of epithelial markers. Prostaglandin E receptor 4 (PTGER4) was the primary receptor that responded to PGE₂ treatment, and PTGER4 knockdown or pharmacological inhibition with GW-627368 suppressed FABP3 expression in bEECs. Moreover, uterine samples from dairy cows at different stages of the estrous cycle showed that FABP3 expression was significantly elevated in the endometrium tissue during mid-diestrus compared to metestrus, with predominant localization in the luminal and superficial glandular epithelium. Collectively, these findings indicate that FABP3 regulates lipid droplet accumulation and adhesion ability in bEECs via the PGE₂/PTGER4/PPAR signaling axis, providing new insights into the metabolic regulation of endometrial receptivity in ruminants.

Prostaglandin E₂ (PGE₂) plays a critical role in regulating uterine endometrial function and supporting embryonic development during early pregnancy in ruminants. However, its precise roles in shaping the uterine microenvironment remain unclear. Herein, 1 mg PGE₂ was infused daily into the uterus of dairy heifers from days 12 to 14 of the estrus cycle. ULF was subsequently collected for integrated proteomic, metabolomic, and targeted lipidomic analyses. In addition, bovine endometrial epithelial cells were used to evaluate the effects of PGE₂ on epithelial adhesion and responsiveness to interferon tau (IFNT). PGE₂ infusion resulted in 909 differentially abundant proteins (DAPs), which are primarily associated with early embryonic development, immune regulation, and cell adhesion. Untargeted metabolomics analysis identified 587 altered metabolites, which were enriched in sphingolipid, arachidonic acid, phenylalanine, and tryptophan metabolism. Proteomic–metabolomic analyses showed that these alterations were primarily associated with early embryonic development, immune regulation, and cell adhesion. Targeted lipidomic analysis showed a global reduction in lipid accumulation, with glycerophospholipid metabolism and choline metabolism most significantly affected. In vitro, PGE₂ reduced epithelial microvilli density, increased osteopontin (OPN) expression, and decreased the expression of junctional proteins (zona occludens-1 (ZO-1), E-cadherin (CDH1), and fibronectin 1 (FN1)). Moreover, PGE₂ enhanced the responsiveness of bEECs to IFNT by interferon alpha/beta receptor 1 (IFNAR1) and IFNAR2, and prostaglandin E receptor 4 (PTGER4) was identified as the primary receptor mediating this response. Collectively, these findings suggest that PGE₂ may modulate lipid metabolism and adhesion-related processes in the endometrium and influence endometrial responsiveness to IFNT, providing insights into molecular mechanisms associated with pregnancy establishment in dairy cows.

The moderate pathogenicity coupled with high host susceptibility of Eimeria maxima has precipitated substantial economic losses in the poultry industry. Addressing challenges such as emerging drug resistance underscores the imperative for innovative vaccine strategies. This study developed a novel DNA vaccine to solve this challenge by fusing E. maxima elongation factor-1α (EmEF1α) with chicken chemokine XCL1 (ChXCL1) in the pVAX1 vector. The recombinant plasmid, designated pVAX1-ChXCL1-EmEF1α, was successfully constructed and confirmed to express the ChXCL1-EmEF1α fusion protein in vitro. Immunization of chickens with this DNA vaccine elicited a robust and balanced immune response, characterized by significantly increased proportions of CD4⁺ (11.76%) and CD8⁺ (5.58%) T lymphocytes, elevated levels of Th1-associated cytokines (IFN-γ and IL-12), and strong antigen-specific IgG and IgA antibody responses. Following experimental challenge with E. maxima, vaccinated birds exhibited substantial protection: a 66.4% reduction in oocyst shedding, a 71.7% improvement in relative weight gain, marked attenuation of intestinal lesions, and an anticoccidial index (ACI) of 170. These findings demonstrate that the ChXCL1-EmEF1α DNA vaccine effectively enhances both cellular and humoral immunity. Collectively, this study validates ChXCL1 as a potent molecular adjuvant and establishes the “antigen–adjuvant” fusion DNA platform as a promising strategy for developing next-generation vaccines against avian coccidiosis.

Heat stress (HS) causes reproductive damage in female mammals, including pigs, cattle, and sheep. As the primary site of estrogen (E₂) biosynthesis, follicular granulosa cells (GCs) act as the critical target of HS injury. Previous studies have shown that cinnamaldehyde (CA) effectively participates in reproductive regulation in mice. Therefore, female mice and their follicular GCs were taken as the research subjects in this study. First, we adopted ELISA and H&E staining to investigate the effects of CA on ovarian follicular histology and E₂ secretion in mice. Second, CCK-8 assay, flow cytometry, and ELISA were applied to clarify how CA regulates proliferation, apoptosis, and E₂ secretion of mouse follicular GCs under HS. Finally, RT-qPCR and Western blotting (WB) were used to elucidate the protective effects of CA together with its underlying molecular mechanisms. Animal experiment results revealed that HS elevated the proportion of primordial and primary follicles and suppressed E₂ secretion. Oral gavage of mice with CA at 25 mg/kg exhibited no obvious hepatotoxicity. This dosage effectively increased the percentage of secondary and antral follicles, alleviated HS-induced histological damage in ovaries, and raised serum E₂ levels both under normal conditions and HS. Further in vitro cell experiments confirmed that HS reduced cell viability and accelerated apoptosis in mouse follicular GCs. HS decreased estrogen secretion by downregulating the relative protein expression of StAR and CYP19A1. Treatment with CA at a concentration of 2.5 × 10⁻⁵ M significantly increased cell viability and inhibited excessive apoptosis in mouse follicular GCs under HS. Under HS conditions, CA treatment elevated E₂ secretion in mouse follicular GCs by upregulating the relative protein expression of StAR and CYP19A1. In conclusion, the findings of this study indicate that CA holds promise as a natural anti-HS additive.