Sonic hedgehog protein promotes bone marrow-derived endothelial progenitor cell proliferation, migration and VEGF production via Pl 3-kinase/Akt signaling pathways

Aim: To investigate the effects of Sonic hedgehog (shh) protein on bone marrow-derived endothelial progenitor cells (BM-EPC) proliferation, migration and vascular endothelial growth factor (VEGF) production, and the potential signaling pathways involved in these effects. Methods: Bone marrow-derived Flk-1+ cells were enriched using the MACS system from adult Kunming mice and then BM-EPC was cultured in gelatin-coated culture dishes. The effects of shh N-terminal pep-tide on BM-EPC proliferation were evaluated using the MTT colorimetric assay. Cell migration was assayed using a modified Boy den chamber technique. The production of VEGF was determined by ELISA and immunofluorescence analysis. The potential involvement of PKC and PI3K signaling pathways was explored using selective inhibitor or Western blot. Results: The proliferation, migration and VEGF production in BM-EPC could be promoted by endogenous shh N-terminal peptide at concentrations of 0.1 ug/mL to 10 ug/mL, and could be inhibited by anti-shh antibodies. Shh-mediated proliferation and migration in BM-EPC could be partly attenuated by anti-VEGF. Phospho-PI3 -kinase expression in newly separated BM-EPC was low, and it increased significantly when exogenous shh N-terminal peptide was added, but could be attenuated by anti-human/mouse shh N-terminal peptide antibody. Moreover, the inhibitor of the PI3-kinase, but not the inhibitor of the PKC, significantly inhibited the shh-mediated proliferation, migration and VEGF production. Conclusion: Shh protein can stimulate bone marrow-derived BM-EPC proliferation, migration and VEGF production, which may promote neovascularization to ischemic tissues. This results also suggests that the PI3-kinase/Akt signaling pathways are involved in the angiogenic effects of shh.