Research Paper Volume 13, Issue 6 pp 7781—7799

Twist1 signaling in age-dependent decline in angiogenesis and lung regeneration

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Figure 2. Twist1 controls age-dependent decline in VEGFR2 expression through PGC1α. (A) Graph showing the mRNA levels of PGC1α and VEGFR2 in aged (>50 years old) human adipose ECs treated with lentivirus overexpressing PGC1α or control virus (vector alone) (left, n=4, mean ± s.e.m., *, p<0.05). Representative immunoblots showing VEGFR2, PGC1α, and β-actin protein levels in aged human adipose ECs treated with lentivirus overexpressing PGC1α or control virus (middle). Graph showing VEGFR2 and PGC1α protein levels normalized by β-actin protein levels in aged human adipose ECs treated with lentivirus overexpressing PGC1α or control virus (right, n=3, mean ± s.e.m., *, p<0.05). (B) Graph showing the mRNA levels of PGC1α in aged human adipose ECs treated with PGC1α siRNA or control siRNA with irrelevant sequences (left, n=5, mean ± s.e.m., *, p<0.05). Graph showing the mRNA levels of VEGFR2 in aged human adipose ECs treated with Twist1 siRNA, PGC1α siRNA, or in combination (right, n=5, mean ± s.e.m., *, p<0.05). (C) Graph showing the mRNA levels of ERRα in young vs. aged human adipose ECs (left, n=5, mean ± s.e.m., *, p<0.05). Representative immunoblots showing ERRα and β-actin protein levels in young vs. aged human adipose ECs (middle). Graph showing ERRα protein levels normalized by β-actin protein levels in young vs. aged human adipose ECs (right, n=3, mean ± s.e.m., *, p<0.05). (D) ChIP analysis showing the immunoprecipitation levels of VEGFR2 promoter coimmunoprecipitating with control IgG or ERRα antibody in human adipose ECs isolated from young (<50 years old) vs. old (>50 years old) adipose tissues (n=5, mean ± s.e.m., *, p<0.05). (E) Graph showing the mRNA levels of ERRα in aged human adipose ECs treated with Twist1 siRNA or PGC1α virus (n=4, mean ± s.e.m., *, p<0.05). (F) ChIP analysis showing the immunoprecipitation levels of VEGFR2 promoter coimmunoprecipitating with control IgG or ERRα antibody in human adipose ECs isolated from old (>50 years old) adipose tissues treated with PGC1α virus or control virus (n=4, mean ± s.e.m., *, p<0.05).