(569) The Role of ANGPTL4 Deficiency in Hypobaric Hypoxia-Induced Ovarian Injury: A Metabolic-Immune Regulation Study via Dendritic Cell ceRNA Networks

Introduction High-altitude hypobaric hypoxia is a significant environmental factor in female ovarian function decline, though the underlying immunological mechanisms remain incompletely understood. Dendritic cells (DCs), as key regulators of the ovarian immune microenvironment, show altered responses under hypoxic conditions, yet their specific role in ovarian injury pathogenesis requires clarification. Angiopoietin-like protein 4 (ANGPTL4) has been identified as a hypoxia-responsive factor, but its function in mediating metabolic-immune crosstalk within DCs during ovarian dysfunction warrants further investigation. Objective This study aimed to systematically investigate the role of ANGPTL4 in hypoxic ovarian injury, with specific focus on: (1) its expression patterns across DC subsets in hypoxic ovaries; (2) how ANGPTL4 deficiency influences DC immunophenotype and function through metabolic reprogramming; and (3) the contribution of metabolic-immune coupling imbalance to this pathological process. Methods We integrated microarray data from public dataset GSE60779 with in-house whole-transcriptome sequencing data from mouse ovarian tissues exposed to hypobaric hypoxia or normoxic conditions. Samples were stratified by ANGPTL4 expression levels. Differential expression analysis was performed using limma and DESeq2 (∣log₂FC∣ > 0.5, p < 0.05). Gene identifiers were converted via BiomaRt, and common differentially expressed genes were identified through intersection analysis, followed by Gene Ontology and KEGG enrichment analyses. Protein-protein interaction networks were constructed using STRING, with hub genes identified through integration of multiple topological algorithms from MCODE and CytoHubba plugins in Cytoscape. RNA interactions were predicted using multiMiR and Starbase, enabling construction of a ceRNA regulatory network based on expression trends and correlation patterns. Gene Set Enrichment Analysis provided pathway-level functional annotation. Experimental validation was performed using western blotting (WB), reverse transcription quantitative polymerase chain reaction (RT-qPCR), and dual-luciferase reporter assays. Results We identified 67 common differentially expressed genes significantly associated with both ANGPTL4 expression and hypoxic stress. Functional enrichment analysis revealed these genes were enriched in HIF-1 signaling pathway, glucose metabolism, and antigen processing and presentation, suggesting ANGPTL4 may participate in hypoxic ovarian injury through regulation of cellular metabolism and immune responses. Protein-protein interaction network analysis identified six core hub genes (P4HA1, SLC16A3, EGLN3), most showing downregulation under hypoxia. Gene Set Enrichment Analysis confirmed substantial involvement of these hub genes in oxidative phosphorylation and tricarboxylic acid cycle, indicating ANGPTL4 deficiency may suppress key metabolic gene expression, leading to disrupted energy metabolism in DCs and subsequent impairment of immune functions. We established a ceRNA regulatory network comprising 9 miRNAs, 2 lncRNAs, and 78 circRNAs, which together with hub genes forms a multi-level regulatory framework for ANGPTL4 under hypoxic stress. Conclusions Our findings suggest that under hypoxic stress, aberrant ANGPTL4 expression modulates downstream hub genes through a core ceRNA regulatory network, driving metabolic reprogramming in DCs characterized by impaired oxidative phosphorylation. This metabolic alteration promotes immunophenotypic shift toward tolerance, disrupts ovarian immune microenvironment homeostasis, and ultimately contributes to ovarian dysfunction. These results provide insights into post-transcriptional regulatory mechanisms governing ovarian injury under hypoxic conditions. Disclosure No