Figure 5. Ang II upregulates HIF1α by ALKBH1-mediated m6A modification. (A, B) Images and quantification of IHC staining for HIF1α in VSMCs of thoracic aortas from mice and rats with hypertension. Scale bar: 50 μm. Data as mean ± SD., *p < 0.05, **p < 0.01 by unpaired Student’s t test. (C–E) HIF1α mRNA and protein analysis by RT-qPCR and western blot assay in HASMCs with Si-ALKBH1 and/or Ang II treatment. (F) Integrative genomics viewer plots showing increasing m6A peaks (red-labeled ChIP-1 to -3) in human HIF1α gene (hg19) region with ALKBH1 knockdown by siRNA from previous study (GEO: GSE118093). (G, H) Chromatin immunoprecipitation (ChIP) assay with m6A (G) or ALKBH1 (H) antibody used for immunoprecipitation on HIF1α gene fragments in treated HASMCs; normal IgG was an IP control. Data are mean ± SD (n= 4/group). *P<0.05, **P<0.01, ***P<0.001 vs the Si-CN; #P<0.05 vs Si-CN and Ang II treatment by one-way ANOVA followed by Bonferroni’s multiple comparison test. Ctrl, sterile saline. Ang II, angiotensin II. LS, Low salt (0.4% NaCl). HS, High salt (8% NaCl).