Poly(ADP-ribose) polymerase-1 regulates fibroblast activation in systemic sclerosis
Poly(ADP-ribose) polymerase-1 regulates fibroblast activation in systemic sclerosis
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DOI：
10.1136/annrheumdis-2017-212265
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发表时间：
2018-02
影响因子：
27.4
通讯作者：
Yun Zhang;S. Pötter;Chih-Wei Chen;R. Liang;K. Gelse;I. Ludolph;R. Horch;O. Distler;G. Schett;J. Distler;C. Dees
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文献类型：
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作者：
Yun Zhang;S. Pötter;Chih-Wei Chen;R. Liang;K. Gelse;I. Ludolph;R. Horch;O. Distler;G. Schett;J. Distler;C. Dees
目的聚（adp -核糖）聚合酶-1 （PARP-1）将带负电荷的adp -核糖单元转移到靶蛋白上。这种修饰对靶蛋白有明显的调节作用。最近的研究表明，PARP-1可以聚（adp -核糖体）- (PARylate) Smad蛋白。然而，PARP-1在系统性硬化症（SSc）发病机制中的作用尚未被研究。方法采用定量PCR和免疫组织化学方法检测PARP-1的表达。采用甲基化DNA免疫沉淀法分析DNA甲基化。采用报告基因法、染色质免疫沉淀法和靶基因分析法评估转化生长因子-β (tgf -β)信号。研究了PARP-1失活对博莱霉素诱导和拓扑异构酶诱导的纤维化以及紧致皮肤-1 （Tsk-1）小鼠的影响。结果PARP-1在SSc患者中表达降低，尤其是在成纤维细胞中。PARP-1的启动子在SSc成纤维细胞和tgf β刺激的正常成纤维细胞中高甲基化。DNA甲基转移酶（dnmt）的抑制降低了启动子甲基化并重新激活了PARP-1的表达。PARP-1的失活促进了磷酸化Smad3的积累，增强了Smad依赖性转录，上调了TGFβ/Smad靶基因的表达。抑制PARP-1可增强体外TGFβ对胶原释放和肌成纤维细胞分化的影响，并加重体内实验性纤维化。PARP-1缺乏诱导对博来霉素更严重的纤维化反应，皮肤增厚、羟脯氨酸含量和肌成纤维细胞计数增加。抑制PARylation也加重了Tsk-1小鼠和拓扑异构酶诱导纤维化小鼠的纤维化。结论PARP-1负调控tgf - β信号通路在实验性皮肤纤维化中的作用。因此，SSc成纤维细胞中PARP-1的下调可能直接导致TGFβ信号过度活跃和SSc成纤维细胞的持续激活。
Objectives The enzyme poly(ADP-ribose) polymerase-1 (PARP-1) transfers negatively charged ADP-ribose units to target proteins. This modification can have pronounced regulatory effects on target proteins. Recent studies showed that PARP-1 can poly(ADP-ribosyl)ate (PARylate) Smad proteins. However, the role of PARP-1 in the pathogenesis of systemic sclerosis (SSc) has not been investigated. Methods The expression of PARP-1 was determined by quantitative PCR and immunohistochemistry. DNA methylation was analysed by methylated DNA immunoprecipitation assays. Transforming growth factor-β (TGFβ) signalling was assessed using reporter assays, chromatin immunoprecipitation assays and target gene analysis. The effect of PARP-1 inactivation was investigated in bleomycin-induced and topoisomerase-induced fibrosis as well as in tight-skin-1 (Tsk-1) mice. Results The expression of PARP-1 was decreased in patients with SSc, particularly in fibroblasts. The promoter of PARP-1 was hypermethylated in SSc fibroblasts and in TGFβ-stimulated normal fibroblasts. Inhibition of DNA methyltransferases (DNMTs) reduced the promoter methylation and reactivated the expression of PARP-1. Inactivation of PARP-1 promoted accumulation of phosphorylated Smad3, enhanced Smad-dependent transcription and upregulated the expression of TGFβ/Smad target genes. Inhibition of PARP-1 enhanced the effect of TGFβ on collagen release and myofibroblast differentiation in vitro and exacerbated experimental fibrosis in vivo. PARP-1 deficiency induced a more severe fibrotic response to bleomycin with increased dermal thickening, hydroxyproline content and myofibroblast counts. Inhibition of PARylation also exacerbated fibrosis in Tsk-1 mice and in mice with topoisomerase-induced fibrosis. Conclusion PARP-1 negatively regulates canonical TGFβ signalling in experimental skin fibrosis. The downregulation of PARP-1 in SSc fibroblasts may thus directly contribute to hyperactive TGFβ signalling and to persistent fibroblast activation in SSc.