The transcription factor GLI2 as a downstream mediator of transforming growth factor-β-induced fibroblast activation in SSc
The transcription factor GLI2 as a downstream mediator of transforming growth factor-β-induced fibroblast activation in SSc
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DOI：
10.1136/annrheumdis-2016-209698
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发表时间：
2017-04-01
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：
Liang, Ruifang;Sumova, Barbora;Distler, Joerg H. W.
目的 Hedgehog 信号传导在系统性硬化症 (SSc) 纤维化的发病机制中发挥着关键作用。除了具有 GLI 转录因子平滑 (SMO) 依赖性激活的经典刺猬信号传导之外，GLI 还可以独立于经典刺猬配体和受体而被激活（所谓的非经典途径）。在这里，我们的目的是评估非典型刺猬信号在SSc中的作用，并测试同时靶向典型和非典型刺猬信号通路的直接GLI抑制剂的功效。方法使用GLI抑制剂GANT-61来抑制典型和非典型刺猬信号，而SMO抑制剂vismodegib用于选择性靶向典型刺猬信号。此外，使用 Cre-LoxP 系统选择性地去除成纤维细胞中的 GLI2。在培养的成纤维细胞、博来霉素诱导的肺纤维化和过度表达组成型活性 TGF-β 受体 I 的小鼠中分析了 GLI2 的药理学或遗传对转化生长因子-β (TGF-β) 信号传导的影响。结果 TGF-β 以 Smad3 依赖性方式上调 GLI2，并诱导 GLI2 的核积累和 DNA 结合。成纤维细胞特异性敲除 GLI2 可保护小鼠免受 TBRact 诱导的纤维化。在实验性皮肤和肺纤维化中，与直接 GLI 抑制剂联合靶向经典和非经典刺猬信号比使用 SMO 抑制剂选择性靶向经典刺猬信号产生更有效的抗纤维化作用。结论我们的数据表明，刺猬通路和 TGF-β 信号均汇聚至 GLI2，并且 GLI2 整合这些信号以促进组织纤维化。这些发现可能具有转化意义，因为 GLI2 的非选择性抑制剂已投入临床使用，而选择性分子目前正在开发中。
Objectives Hedgehog signalling plays a critical role during the pathogenesis of fibrosis in systemic sclerosis (SSc). Besides canonical hedgehog signalling with smoothened (SMO)-dependent activation of GLI transcription factors, GLI can be activated independently of classical hedgehog ligands and receptors (so-called non-canonical pathways). Here, we aimed to evaluate the role of non-canonical hedgehog signalling in SSc and to test the efficacy of direct GLI inhibitors that target simultaneously canonical and non-canonical hedgehog pathways.Methods The GLI inhibitor GANT-61 was used to inhibit canonical as well as non-canonical hedgehog signalling, while the SMO inhibitor vismodegib was used to selectively target canonical hedgehog signalling. Furthermore, GLI2 was selectively depleted in fibroblasts using the Cre-LoxP system. The effects of pharmacological or genetic of GLI2 on transforming growth factor-beta (TGF-beta) signalling were analysed in cultured fibroblasts, in bleomycin-induced pulmonary fibrosis and in mice with overexpression of a constitutively active TGF-beta receptor I.Results TGF-beta upregulated GLI2 in a Smad3-dependent manner and induced nuclear accumulation and DNA binding of GLI2. Fibroblast-specific knockout of GLI2 protected mice from TBRact-induced fibrosis. Combined targeting of canonical and non-canonical hedgehog signalling with direct GLI inhibitors exerted more potent antifibrotic effects than selective targeting of canonical hedgehog signalling with SMO inhibitors in experimental dermal and pulmonary fibrosis.Conclusions Our data demonstrate that hedgehog pathways and TGF-beta signalling both converge to GLI2 and that GLI2 integrates those signalling to promote tissue fibrosis. These findings may have translational implications as non-selective inhibitors of GLI2 are in clinical use and selective molecules are currently in development.