Angiogenin Attenuates Scar Formation in Burn Patients by Reducing Fibroblast Proliferation and Transforming Growth Factor β1 Secretion

BACKGROUND: Deep burn wounds have a high tendency to form hypertrophic scars. Previously, we found that angiogenin promoted neovascularization during deep burn wound healing. However, the association between angiogenin and scar formation is unclear. METHODS: We obtained human burn scar tissues from patients who underwent scar surgery and examined the role of angiogenin in scar tissues and determined its effects in scar fibroblasts and on transforming growth factor β1 (TGF-β1) secretion. RESULTS: Our results showed an inverse correlation between angiogenin expression and scar severity. Next, we examined the effects of angiogenin in scar fibroblasts. We found that angiogenin was persistently expressed in human scar fibroblasts and that angiogenin expression significantly increased with time in the culture medium of scar fibroblasts. Treatment of scar fibroblasts with recombinant angiogenin significantly decreased their proliferation and TGF-β1 secretion. Moreover, angiogenin inhibited TGF-β1-mediated Smad2 signaling pathway. CONCLUSION: Our data suggest a negative role of angiogenin in fibroblast proliferation via TGF-β1-mediated Smad2 signaling pathway.