Fig. 4.

Metformin promotes the expression of HIF-1α by inhibiting the expression of YAP1/TAZ in HMECs under hypoxic conditions. a qRT‒PCR analysis of the inhibitory efficiency of siRNAs targeting HIF-1α. n = 3 per group. b qRT‒PCR analysis of the expression of HIF-1α and its target genes Vegfa and Lrg1 in the si-HIF-1α-transfected HMECs with or without metformin treatment under hypoxic conditions (1% O₂). Met: metformin. n = 3 per group. Immunofluorescence staining images and quantification showing the protein levels of HIF-1α (c), YAP1 (d), and TAZ (e) in the HMECs treated with PBS (control) or metformin under hypoxic conditions. Scale bar: 20 μm. n = 9 per group. f qRT‒PCR analysis of the inhibitory efficiency of siRNAs targeting YAP1 or TAZ. n = 3 per group. g Immunofluorescence staining images and quantification showing the protein level of HIF-1α in the hypoxia-cultured HMECs from the si-Con, si-YAP1, si-TAZ, si-Y/T, and si-Y/T + Met groups. Y/T: YAP1 and TAZ. Scale bar: 20 μm. n = 3 per group. Data are presented as the mean ± SEM. ^*P < 0.05, ^**P < 0.01, and ^***P < 0.001