骨髓间充质干细胞来源外泌体通过TGF-β1/smad2/3信号通路抑制增生性瘢痕的机制研究

Study on the mechanism of BMSC-exos inhibiting hypertrophic scar through TGF-β1/smad2/3 signal pathway

目的探讨骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMSCs)来源外泌体对增生性瘢痕成纤维细胞(hypertrophic scar-derived fibroblasts,HSFs)增殖和迁移能力的影响,并验证BMSCs来源外泌体抑制HSFs合成胶原的信号通路。方法分离并培养SD大鼠BMSCs、BMSC来源外泌体及SD大鼠HSFs,设置空白对照组(PBS组),实验组(BMSCs来源外泌体组),阴性对照组(去外泌体间充质干细胞浓缩上清液组)。流式细胞周期实验及细胞划痕实验检测外泌体对HSFs增殖及迁移的影响。荧光定量聚合酶链反应(polymerase chain reaction,PCR)检测3组细胞中TIMP-1、基质金属蛋白酶1、Ⅰ型胶原、Ⅲ型胶原的mRNA表达。Western blot检测3组细胞中转化生长因子β1、α-平滑肌肌动蛋白、Ⅰ型胶原的蛋白水平及smad2/3的磷酸化水平。结果BMSCs来源外泌体抑制了HSFs的增殖和迁移能力。与PBS组比较,BMSCs来源外泌体组TIMP-1、Ⅰ型胶原、Ⅲ型胶原mRNA表达显著降低,而基质金属蛋白酶1 mRNA表达显著升高,差异有统计学意义(P<0.05)。与PBS组比较,BMSCs来源外泌体组转化生长因子β1、α-平滑肌肌动蛋白、Ⅰ型胶原的蛋白水平及smad2/3的磷酸化水平显著降低,差异有统计学意义(P<0.05)。结论BMSCs来源外泌体抑制了HSFs的增殖及迁移,通过TGF-β1/smad2/3信号通路抑制胶原合成,从而有利于抑制瘢痕增生。

Objective To study the effect of bone marrow mesenchymal stem cell-derived exosomes(BMSC-exos)on the proliferation and migration ability of hypertrophic scar-derived fibroblasts(HSFs),and to verify the signaling pathway of BMSC-exos inhibiting collagen synthesis by HSFs.Methods Bone marrow mesenchymal stem cells(BMSCs),BMSC-exos and HSFs in SD rats were isolated and cultured.They were divided into blank control group(PBS group),experimental group(BMSC-exos group),and negative control group(exocrine mesenchymal stem cell concentrated supernatant group).The effect of exosomes on proliferation and migration of HSFs was detected by flow cytometry and cell scratch test.The mRNA expressions of TIMP-1,matrix metalloproteinase 1(MMP-1),typeⅠcollagen(Col-Ⅰ)and typeⅢcollagen(Col-Ⅲ)in cells of the three groups were detected by fluorescence quantitative polymerase chain reaction(FQ-PCR)method.The protein levels of transforming growth factor-β1(TGF-β1),α-smooth muscle actin(α-SMA)and Col-Ⅰ,and the phosphorylation level of smad2/3 in the three groups were detected by Western blot.Results BMSC-exos inhibited the proliferation and migration ability of HSFs.The mRNA expression of TIMP-1,Col-Ⅰ,and Col-Ⅲin BMSC-exos group were significantly decreased,while the mRNA expression of MMP-1 was significantly increased,showing significant difference(P<0.05).The protein levels of TGF-β1,α-SMA and Col-Ⅰand the phosphorylation level of smad2/3 in BMSC-exos group were decreased significantly,suggesting significant difference(P<0.05).Conclusion BMSC-exos inhibit the proliferation and migration of HSFs,and inhibit the collagen synthesis of HSFs through TGF-β1/smad2/3 signal pathway,thus playing a role in inhibiting the development of hypertrophic scar.