【摘要】 目的探讨血小板衍生生长因子A(PDGF-AA)/PDGF受体α(PDGFR-α)信号通路对系统性硬化症(SSc)患者皮损成纤维细胞(FB)增殖和转分化为MFB的作用。方法 SSc患者皮损和正常皮肤原代FB体外培养、鉴定,用免疫细胞化学法检测其中的α-SMA;分别予两组FB不同浓度的PDGF-AA刺激,用MTT法检测其对FB增殖的作用;对两组FB分别予TGF-β1、PDGF-AA及两者联合刺激,用RT-PCR法检测其PDGFR-αmRNA、α-SMA mRNA的表达水平。结果两组FB形态虽相似,但SSc FB中α-SMA呈阳性,正常皮肤则为阴性;SSc FB增殖的饱和浓度高于对照组,在一定浓度与饱和浓度间两组FB都呈剂量依赖方式增殖(P<0.05);不论有无PDGF-AA刺激及刺激浓度大小,SSc FB增殖程度均高于对照组(P<0.05);除单用TGF-β1对正常皮肤FB表达PDGFR-αmRNA无影响外,TGF-β1、PDGF-AA或两者联合刺激均可上调两组FB中PDGFR-αmRNA、α-SMA mRNA的表达水平,以两者联合刺激作用最强;不论有无刺激或何种刺激,SSc FB中PDGFR-αmRNA、α-SMAmRNA表达水平均高于正常皮肤FB(P<0.05);PDGFR-αmRNA和α-SMA mRNA的表达水平依照未处理、PDGF-AA、TGF-β1及TGF-β1+PDGF-AA的顺序渐次增加,两者呈高度正相关(r=0.925,P<0.05)。结论 SSc患者皮损来源的FB存在着向MFB转分化的显著特性,SSc FB胞膜表面过表达的PDGFR-α可结合较多的PDGF-AA配体,从而介导更强的促进FB增殖和转分化为MFB作用,TGF-β1则可增强此作用。更多还原

【Abstract】 Objective To study the role of platelet-derived growth factor A(PDGF-A)/PDGF receptor-α(PDGFR-α) signaling pathway in the proliferation and transdifferentiation of fibroblasts(FB) into myofibroblasts(MFB) in the skin lesions of patients with systemic sclerosis(SSc).Methods The primary FBs isolated from the skin lesions of SSc patients and normal adult skin cultured in vitro were examined for α-smooth muscle actin(α-SMA) using immunocytochemistry.The FBs were incubated with different concentrations of PDGF-AA and the changes in their proliferative activity were quantified with MTT assay.RT-PCR was used to determine the effects of transforming grwoth factor-β1(TGF-β1) and PDGF-AA,either alone or in combination,on the expression levels of PDGFR-α and α-SMA mRNA in the FBs.Results Although the FBs of the two groups were morphologically similar,only FBs from the skin lesion showed positive staining for α-SMA.Below the saturated concentration of PDGF,the FBs in the two groups both proliferated in a dose-dependent manner(P<0.05),but the FBs from the SSc lesions always showed a significantly higher proliferative activity(P<0.05).PDGF-AA and TGF-β1,alone or in combination,up-regulated the expression level of PDGFR-α and α-SMA mRNA in the FBs from SSc lesions;simialr results were obtained in the control FBs,except that TGF-β1 alone did not influence PDGFR-α mRNA expression.PDGFR-α and α-SMA mRNA alwasys showed higher expressions in FBs in SSc lesions than in the control FBs with the same treatments(P<0.05).The expression levels of PDGFR-α and α-SMA mRNA increased in the order of untreated,PDGF-AA,TGF-β1 and PDGF-AA plus TGF-β1 groups and showed a strong positive correlation between them(r=0.925,P<0.05).Conclusions The FBs from the skin lesions of SSc patients have a distinct feature of transdifferentiation into MFB.Over-expression of PDGFR-α on the surface of FBs from SSc lesions can bind more PDGF-AA ligands to increase cell proliferation and promote transdifferentiatiation to MFB,and TGF-β1 further enhances this effect.更多还原