Abstract 20102: The Neuropeptide Catestatin acts as an Angiogenic Factor via Basic Fibroblast Growth Factor Signaling
Introduction: The neuropeptide catestatin (CST) is up-regulated in neuronal cells under hypoxia and in cutaneous wounds and induces monocyte migration. Since we found that CST induces chemotaxis and proliferation of endothelial cells (EC) and promotes in-vitro as well as in-vivo angiogenesis (cornea neovascularization assay, hind limb ischemia model; Circulation, Nov 2009; 120: S1122) we investigated the mechanism of CST induced angiogenesis.
Methods and Results: In-vitro matrigel experiments revealed that CST induces capillary tube formation comparable to classic angiogenic factors like basic fibroblast growth factor (bFGF). CST induced angiogenesis could be blocked by a neutralizing bFGF-antibody (Ab) (CST 1nM 2.05±0.08, bFGF 20 ng/ml 2.25±0.09, CST+bFGF-Ab 1:1000 1.1±0.05; n=4, P<0.01 CST vs. CST+bFGF-Ab). Interestingly, bFGF mRNA was not up-regulated by CST over a broad range of concentrations and time-points but we found that EC stimulated by CST release, MAPK dependent, bFGF into cell supernatant with a maximum at 1 hour [pg/ml: Ctr 26.6±2.2, CST 53.8±2.4, PD (=MAPK inhibitor) 22.3±0.98, PD±CST 21.2±1.04, P<0.01 CST vs. Ctr and CST vs. PD+CST,n=4]. Additionally immunoprecipitation-studies revealed phoshorylation of FGF-receptor-1 after treatment of EC with CST. Western blot assays showed a biphasic activation of the ERK1/2 signalling pathway by CST with a fast activation at 10 minutes and a later activation at 50 minutes. The late CST-activation could be blocked by a bFGF-Ab indicating that bFGF might be important for a continuous activation of the MAPK-pathway in CST induced actions. To investigate an involvement of bFGF in CST induced angiogenesis in-vivo mice were subjected to hind-limb ischemia operation and treated with CST (20 μg every other day in adductor muscle for 4 weeks) and with either a neutralizing monoclonal bFGF-Ab or IgG. FGF-Ab impaired limb reperfusion (Laser Doppler Perfusion Imaging ratio ischemic/non ischemic limb: CST+IgG 0.75±0.03 vs. CST+bFGF-Ab 0.46±0.04; n=6; P<0.01) and increased necrosis score (CST+IgG 1.14±0.14 vs. CST+bFGF-Ab 2.16±0.28; n=6; P<0.05) compared with IgG.
Conclusion: In summary our data indicate that CST induced angiogenesis in-vitro and in-vivo is mediated by a bFGF-dependent mechanism.
- © 2010 by American Heart Association, Inc.