Fig. 6
LPAR3 promotes the HIF-2α‒EPO axis via the PI3K‒AKT pathway. A Heatmap of the downregulated genes enriched in the PI3K‒Akt signaling pathway in the kidneys of hypoxic mice with LPAR3 deficiency. B The total renal AKT and p-AKT levels in the WT and Lpar3−/− mice under normoxic or hypoxic conditions (8% O2) were determined by Western blotting, n = 6. The p value was determined by 2-way analysis of variance (ANOVA) followed by a post hoc test. ***p < 0.001 compared with the isogenic normoxia control; #p < 0.05 between different genotype groups; mean ± SEM. C Hep3B cells were transfected with nonspecific siRNA (NC siRNA), LPAR3 siRNA-1 or LPAR3 siRNA-2 for 48 h and then exposed to 1% O2 for 12 h. Total AKT and phosphorylated AKT (p-AKT) levels were determined via Western blotting. D-F Hep3B cells were starved in serum-free MEM for 24 h, pretreated with or without LY294002 (10 µM) for 20 min, and then challenged with 2S-OMPT for 1 h, followed by hypoxia exposure (1% O2) for 6 h. Total AKT, p-AKT, and HIF-2α protein levels were determined by Western blotting (D). The EPO mRNA expression levels (E) were determined via RT‒qPCR, and the EPO protein levels in the culture medium (F) were determined via ELISAs. The p value was determined by 2-way analysis of variance (ANOVA) followed by a post hoc test. **p < 0.01, ****p < 0.0001 relative to the normoxia control of the same treatment; ###p < 0.001, ####p < 0.0001, between different drug-treated groups; mean ± SD