The transcription factor JunD mediates transforming growth factor β-induced fibroblast activation and fibrosis in systemic sclerosis
The transcription factor JunD mediates transforming growth factor β-induced fibroblast activation and fibrosis in systemic sclerosis
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DOI：
10.1136/ard.2010.148296
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发表时间：
2011-07-01
影响因子：
27.4
通讯作者：
Distler, Joerg H. W.
中科院分区：
文献类型：
--
作者：
Palumbo, Katrin;Zerr, Pawel;Distler, Joerg H. W.
目的转化生长因子-β(TGF-β)已被证实在纤维化疾病中起关键作用。然而，转化生长因子β激活成纤维细胞的分子机制还不完全清楚。本研究探讨了转录因子激活蛋白1(AP-1)家族成员Jund在系统性硬化症(SSC)中作为转化生长因子β信号下游调节因子的作用。方法采用实时定量聚合酶链式反应、免疫荧光、免疫印迹和免疫组织化学等方法检测Jund的表达。典型的Smad通路被小干扰(Si)RNA特异性靶向。用实时荧光定量聚合酶链式反应和羟脯氨酸分析法检测Jund(-/-)成纤维细胞中细胞外基质蛋白的表达。采用博莱霉素诱导的小鼠皮肤纤维化模型，研究Jund在实验性纤维化中的作用。结果Jund在SSC皮肤和培养的成纤维细胞中高表达，且呈转化生长因子β依赖性。在纤维化皮肤中，Jund与pSmad3共定位表达，siRNA沉默Smad3或Smad4可抑制转化生长因子β诱导的Jund。Jund(-/-)成纤维细胞对转化生长因子β的反应较弱，在转化生长因子β刺激下释放的胶原较少。此外，Jund(-/-)小鼠可通过减少真皮增厚、肌成纤维细胞数量减少和皮损皮肤胶原含量降低来预防博莱霉素诱导的纤维化。结论Jund在SSC中高表达，Jund是转化生长因子β促纤维化作用的介导者。考虑到AP-1信号通路的抑制剂最近已经被开发出来，并可用于SSC的临床试验，这些发现可能具有翻译意义。
Objectives Transforming growth factor beta (TGF beta) has been identified as a key player in fibrotic diseases. However, the molecular mechanisms by which TGF beta activates fibroblasts are incompletely understood. Here, the role of JunD, a member of the activator protein 1 (AP-1) family of transcription factors, as a downstream mediator of TGF beta signalling in systemic sclerosis (SSc), was investigated.Methods The expression of JunD was analysed by real-time PCR, immunofluorescence, western blotting and immunohistochemistry. The canonical Smad pathway was specifically targeted by small interfering (si) RNA. The expression of extracellular matrix proteins in JunD deficient (JunD(-/-)) fibroblasts was analysed by real-time PCR and hydroxyproline assays. The mouse model of bleomycin-induced dermal fibrosis was used to assess the role of JunD in experimental fibrosis.Results JunD was overexpressed in SSc skin and in cultured fibroblasts in a TGF beta dependent manner. The expression of JunD colocalised with pSmad 3 in fibrotic skin and silencing of Smad 3 or Smad 4 by siRNA prevented the induction of JunD by TGF beta. JunD(-/-) fibroblasts were less responsive to TGF beta and released less collagen upon stimulation with TGF beta. Moreover, JunD(-/-) mice were protected from bleomycin-induced fibrosis with reduced dermal thickening, decreased myofibroblast counts and lower collagen content of lesional skin.Conclusions These data demonstrate that JunD is overexpressed in SSc and that JunD is a mediator of the profibrotic effects of TGF beta. Considering that inhibitors of AP-1 signalling have recently been developed and are available for clinical trials in SSc, these findings may have translational implications.