Abstract 16517: Protective Effect of Stem Cell Factor In Cardiomyocytes Through Akt- Gsk3β-β-catenin Axis
Background: Circulating hematopoietic cytokines such as granulocyte-colony stimulating factor (G-CSF), stem cell factor (SCF), and vascular endothelial growth factor (VEGF) are involved in the therapeutics for MI.
SCF was reported to be cardiac protective, however, it has been confined to phenomenon and the mechanism by which action in CM has not been revealed. This study was designed to examine the role of SCF in cardiomyocytes (CM).
Methods: To analyze the circulating hematopoietic cytokines, MI patients were recruited and peripheral blood was collected before (basal level) and at 72 hours after stent implantation (follow-up level). The levels of circulating VEGF, SCF, c-kit, and G-CSF were quantified by enzyme-linked immunosorbent assay (ELISA). To examine the role of SCF in CM, SCF-expressing lentiviral vector (Lenti-SCF) was constructed for the efficient and stable overexpression. Reverse transcriptase-polymerase chain reaction (RT-PCR), Western blot, and immunofluorescence staining were performed to study signaling molecules in CM. Hypoxic insult was induced by incubation of CM in hypoxic chamber followed by reoxygenation.
Results: The basal level of SCF in MI patients (466.1 ± 121.9 pg/mL, p < 0.05) was lower than in control patients without coronary artery disease (656.8 ± 124.2 pg/mL, p < 0.01). At 72 hours after PCI, the levels of VEGF, G-CSF, and SCF were increased but the level of c-kit was remained unchanged. CM infected with Lenti-SCF for 2 days successfully overexpressed SCF. In SCF-overexpressed CM (SCF-CM), phosphorylations of Akt and glycogen synthase kinase 3β (GSK3β) were significantly increased. β-catenin, a target of GSK3β, translocated to nucleus in SCF-CM. To confirm the pro-survival effect of SCF, the levels of bcl-2 and bax were analyzed. The ratio of bcl-2 to bax was significantly upregulated in SCF-CM. In hypoxia injury, the levels of phosphorylated Akt and GSK3β were higher in SCF-CM.
Conclusions: The level of circulating SCF was increased after stent implantation, and SCF may have a protective role in CMs through GSK3β-β-catenin activation dependent upon Akt.
- © 2013 by American Heart Association, Inc.