PEDF and 34-mer inhibit angiogenesis in the heart by inducing tip cells apoptosis via up-regulating PPAR-γ to increase surface FasL

Abstract Pigment epithelial-derived factor (PEDF) is a potent anti-angiogenic factor whose effects are partially mediated through the induction of endothelial cell apoptosis. However, the underlying mechanism for PEDF and the functional PEDF peptides 34-mer and 44-mer to inhibit angiogenesis in the heart has not been fully established. In the present study, by constructing adult Sprague–Dawley rat models of acute myocardial infarction (AMI) and in vitro myocardial angiogenesis, we showed that PEDF and 34-mer markedly inhibits angiogenesis by selectively inducing tip cells apoptosis rather than quiescent cells. Peptide 44-mer on the other hand exhibits no such effects. Next, we identified Fas death pathway as essential downstream regulators of PEDF and 34-mer activities in inhibiting angiogenesis. By using peroxisome proliferator-activated receptor γ (PPAR-γ) siRNA and PPAR-γ inhibitor, GW9662, we found the effects of PEDF and 34-mer were extensively blocked. These data suggest that PEDF and 34-mer inhibit angiogenesis via inducing tip cells apoptosis at least by means of up-regulating PPAR-γ to increase surface FasL in the ischemic heart, which might be a novel mechanism to understanding cardiac angiogenesis after AMI.
Source: Apoptosis - Category: Molecular Biology Source Type: research