Vascular Endothelial Growth Factor and Angiopoietin-1 Protected Cardiac Myoblasts From Apoptosis Induced by H2O2

Document Type

Article

Publication Date

3-1-2003

Description

Aim: To explore the protective effects and involved mechanisms of two angiogenic growth factors, vascular endothelial growth factor (VEGF165) and angiopoietin-1 in cardiac myoblasts. Methods: Replication-deficient adenovirus encoding for human VEGF165 (Ad-VEGF165) or angiopoietin-1 (Ad-Ang1) were transfected into H9C2 cardiac myoblasts. Recombinant adenovirus encoding for green fluorescent protein (Ad-GFP) was used as vehicle control. Twenty-four hours later, cell apoptosis was induced by 300 μmmol of H2O2. Genomic DNA was extracted and DNA fragmentation was analyzed in 1.6% agarose gels. Phosphatidylinositol-3 kinase(PI-3 K) activity and bcl-2 expression level were investigated in H9C2 after gene transfection 24 hours later by an immol/Lunoprecipitated kinase assay and Western blot assay respectively. The effect of wartmannin, a specific inhibitor of PI-3 K, on DNA fragmentation, PI-3 K activity and bcl-2 expression was also analyzed by a pre-treatment of 30 minutes before transfection. Results: Apoptotic DNA fragmentation induced by H2O2 was significantly inhibited by the transfaction of Ad-VEGF165 and/or Ad-Ang1 but then aborted by the pretreatment of wartmannin. PI-3 K activity was significantly elevated after Ad-VEGF165 + Ad-Ang1 transfection as compared to Ad-GFP transfection group(2.60 vs 1.32, P < 0.01). Anti-apoptotic factor bcl-2 expression was upregulated in Ad-VEGF165 (2.1-fold), Ad-Ang1 (1.7-fold) and Ad-VEGF165 + Ad-Ang1 (1.7-fold) treated groups as compared to Ad-GFP transfection group. Wortmannin suppressed PI-3 K activiation induced by Ad-VEGF165 (from 1.83 to 0.69, P < 0.05). Ad-Ang1 (from 1.80 to 0.97, P = 0.07) or Ad-VEGF165a + Ad-Ang1 (from 2.60 to 0.42, P < 0.01). However, upregulation of bcl-2 induced by Ad-VEGF165 and/or Ad-Ang1 was not aborted by wortmannin pretreatment. Conclusions: VEGF165 and/or Ang1 can protect cardiac myoblasts from apoptosis induced by H2O2 throught PI-3 K and bcl-2 pathway. The anti-apoptotic function of either VEGF165 or Ang1 could be served as a now therapeutic target including their angiogenic benefits.

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