Abstract 11569: Activation of cAMP/CREB/PGC-1α Pathway Plays a Key Role for a Novel Adenosine-like Angiogenic Agent COA-Cl to Induce Production of Vascular Endothelial Growth Factor (VEGF) in Cultured Human Fibroblasts
COA-Cl is a recently developed pro-angiogenic agent (Figure) that promotes tube forming activity of human umbilical vein endothelial cells that are co-cultured with fibroblasts. Recently, a metabolic stress-related co-transcription factor termed PGC-1α was identified as a novel activator of VEGF gene, a key regulator of angiogenesis. In skeletal muscle, the cAMP/CREB signaling pathway plays a central role in inducing PGC-1α expression. We therefore hypothesized that COA-Cl induces PGC-1α to promote VEGF production by elevating cAMP and activating CREB in fibroblasts. COA-Cl (100 μM for 48 h) augmented VEGF secretion into culture medium of normal human dermal fibroblasts from below the level of detection to 54±4 pg/mL (ELISA, p<0.01 vs. basal). This enhancement of VEGF secretion was associated with up-regulation of mRNA encoding VEGF and PGC-1α (RT-PCR, 2.1±0.3 and 9.9±0.8 fold, p<0.05, respectively). Induction of PGC-1α expression by COA-Cl was attenuated by 49±4% (p<0.01 vs. COA-Cl alone) by H-89 (100 μM), an inhibitor of PKA. Conversely, forskolin (25 μM), a direct stimulator of adenylyl cyclase that increases cAMP, increased VEGF production (423±20 pg/mL, p<0.01 vs. basal) and expression of mRNA encoding both VEGF and PGC-1α. COA-Cl induced an increase in cAMP content (ELISA) and phosphorylation of CREB at Ser133 (immunoblot), a PKA site associated with an increased transcriptional activity of CREB, in a time- and dose-dependent manner (4.4±0.3 and 2.3±0.2 fold at 100 μM COA-Cl for 20 min, p<0.05, respectively). In COS-7 fibroblast-like cells, COA-Cl elevated luciferase activity of transfected reporter construct driven by CRE, which is regulated by cAMP/CREB (2.4±0.1 fold at 200 μM COA-Cl for 24 h). Collectively, our results demonstrate that COA-Cl elevates cAMP and activates CREB in human fibroblasts to induce PGC-1α expression, thereby promoting VEGF transcription and secretion, potentially identifying a novel way to induce therapeutic angiogenesis.
Author Disclosures: R. Okamoto: None. J. Igarashi: None. T. Hashimoto: None. T. Yamashita: None. K. Shoji: None. Y. Kubota: None. N. Sakakibara: None. I. Tsukamoto: None. R. Konishi: None. K. Hirano: None.
- © 2015 by American Heart Association, Inc.