Abstract：Objective: To investigate the roles of HIF-1α and Hepcidin in the pathogenesis of high-altitude polycythemia (HAP).Methods: Peripheral blood hemoglobin concentration [Hb], hemoglobin mass (Hbmass), blood volume, and peripheral blood O2 saturation (SpO2) were measured in subjects with high-altitude polycythemia (HAE group), healthy individuals residing at the same high altitude (HH group), and healthy individuals born at high altitude but residing at low altitude for over 2 years (LH group). ELISA was used to determine the levels of HIF-1α and Hepcidin in peripheral blood serum. HepG2 cells were cultured under hypoxia in vitro, with experimental groups including Control and Hypoxia groups. The expression levels of HIF-1α and Hepcidin mRNA and protein were measured. m6A content analysis, RNA immunoprecipitation (RIP), dual-luciferase reporter assay, and mRNA stability analysis were used to explore the molecular mechanisms by which HIF-1α mediates m6A demethylation of Hepcidin mRNA.Results: Compared with the LH group, the HH group had increased levels of [Hb], Hbmass, and blood volume, and decreased SpO2; compared with the HH group, the HAE group had increased levels of [Hb], Hbmass, and blood volume, and decreased SpO2 (P<0.05). Compared with the Control group, the Hypoxia group showed increased relative expression levels of HIF-1α mRNA and protein, and decreased relative expression levels of Hepcidin mRNA and protein in HepG2 cells (P<0.05). The m6A (%) level in the Hypoxia group was lower than in the Control group (P<0.05). mRNA stability analysis showed that the relative expression level of Hepcidin mRNA in the Hypoxia group was lower than in the Control group (P<0.05). Dual-luciferase reporter assay showed that relative luciferase activity was higher in HepG2 cells co-transfected with Hepcidin 3'-UTR and HIF-1α shRNA compared to cells co-transfected with Hepcidin 3'-UTR and shRNA NT (P<0.05). RIP results showed that the enrichment level of Hepcidin 3'-UTR was higher in the FTO Ab group compared to the IgG group (P<0.05).Conclusion: Hypoxia-induced upregulation of HIF-1α mediates the demethylation of Hepcidin mRNA, contributing to the progression of high-altitude polycythemia.
2024, Vol. 30 
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