P13 S-Propargyl-Cysteine (SPRC) promoted angiogenesis under both normal and ischemic conditions: Possible STAT3-mediated mechanism

Abstract

Background In most western countries, ischemic heart disease (IHD) is the most common cause of death and a major cause of hospital admissions. Conventional drug therapy is designed to effect through anti-oxidation, anti-apoptosis, anti-inflammation and anti-lipidemia to protect against IHD. Since hydrogen sulfide has been reported to induce angiogenesis in vitro and in vivo , we investigated the pro-angiogenic effect of SPRC, a novel water-soluble modulator of endogenous hydrogen sulfide, to provide experimental basis for angiogenesis-mediated drug therapy of IHD. In addition, we revealed STAT3-mediated mechanism involved in hydrogen sulfide-induced angiogenesis. Methods Cell viability assay, cell proliferation assay, cell adhesion assay, wound healing assay, transwell migration assay and tube formation assay were carried out to determine the pro-angiogenic effect of SPRC on endothelial cells in vitro . Matrigel plug assay, rat aortic ring assay, CAM assay and sponge implantation assay were carried out to determine the pro-angiogenic effect of SPRC in vivo . Hind-limb ischemia model and myocardial infarction model were induced to explore the angiogenesis in ischemic condition by laser doppler imaging and angiography. Western blot and immunofluorescence were used to detect the level and location of proteins, respectively. EMSA and CHIP were performed to determine the activation of STAT3 and its downstream promoters. Results SPRC promoted cell proliferation, adhesion, migration and tube formation of primary HUVEC and increased angiogenesis ex vivo and in vivo under both normal and ischemic conditions. In SPRC-induced angiogenesis, phosphorylation of VEGFR2 and STAT3 was elevated significantly, followed by activation of some signal molecules, such as MAPK and Akt. The interaction between VEGFR2 and STAT3 was enhanced after SPRC-treatment. Meanwhile, SPRC induced translocation of STAT3 to nucleus, followed by transcriptional activation of downstream promoters, especially vegf promoter. The critical roles of STAT3 in mediating the pro-angiogenic effect of SPRC were confirmed by RNA interference. Conclusion Based on the proved pro-angiogenic effect of hydrogen sulfide, we proposed and tested SPRC-induced angiogenesis in vitro and in vivo to provide experimental basis for angiogenesis-mediated drug therapy of IHD. More important, we investigated the relative mechanism of STAT3 involved in SPRC-induced angiogenesis, including interaction with VEGFR2 and translocation into nucleus to active transcription.