Abstract / Summary
Abstract Background: Acute hypobaric hypoxia causes metabolic stress, disrupts redox balance, and leads to liver injury, but its molecular impact on hepatic function is unclear. This study examined time-dependent liver proteomic and metabolomic changes during acute hypoxia and their links to oncogenic transformation. Methods: Male SD rats (n=6 per group) were exposed to simulated hypobaric hypoxia at an altitude of 25,000 ft. for durations of 1, 3, or 7 days. Untargeted proteomic and metabolomic analyses were performed on liver tissues to investigate molecular alterations associated with hepatic stress over time. Integrated changes in proteomics and metabolomics were identified and subsequently validated through RT-PCR and immunohistochemistry in liver tissue. Results: Hypoxia induced significant liver injury, evidenced by elevated serum bilirubin, AST, and ALT levels and a reduced liver-to-body weight ratio (p<0.05). Liver metabolomics revealed dynamic time-dependent remodeling at Day1;up-341/Down-20, Day3;up-316/Down-22 and Day7;up-356/Down-10 metabolites as compared to baseline (FC>1.5, p<0.05). These metabolite changes were linked to inflammatory and mitochondrial redox metabolism, including tryptophan (C00099, C00025), amino sugar (C00140), folate (C00576), and TCA cycle metabolism (C00025), alongside suppression of nitrogen metabolism (C00262, C00086), suggesting impaired detoxification (>2FC, p<0.05). Proteomic analysis showed extensive dysregulation, with Day1;up-1091/down-831, Day3; up-1104/down-821, and Day7; up-453/Down-606 proteins (FC>1.5, p<0.05). Enriched proteins were linked to stress responses, lipid and fatty acid metabolism (FADS1, ACOX2, ACOT8, ACADVL, CPT1B), and calcium signaling (PTGS1; >2FC, p<0.05). Integrated multiomics revealed strong associations between TCA cycle activation and inflammatory signaling (R²>0.7, p<0.05). Network analysis connected apoptosis (BAX, APAF1, CDH1, PRKCD), platelet activation (ATP2B3, PPP2R1B), Eph-ephrin signaling (EPHA7, MYH9, LYN, EPHA3), and angiotensin signaling (ACE, CMA1) with disrupted nucleotide, amino acid, and antioxidant metabolism, highlighting Eph-ephrin signaling as a key mediator of hypoxia-induced hepatic inflammation. RTPCR validation confirmed the dysregulation of these pathways (p<0.05). Temporal increase in key genes linked to inflammatory, oxidative, angiogenic and hypoxia linked pathways show significant correlation (r2>0.9, p<0.05) with liver caspase 3 indicating activation of cell death pathways associated with liver injury due to hypoxia. Conclusion: Acute hypobaric hypoxia induces early liver injury marked by redox imbalance, metabolic rewiring, and inflammatory activation, with coordinated proteomic metabolomic disruptions highlighting Eph ephrin signalling as a key driver of hypoxia induced hepatic inflammation and a potential therapeutic target.