XPLN is modulated by HDAC inhibitors and negatively regulates SPARC expression by targeting mTORC2 in human lung fibroblasts
XPLN is modulated by HDAC inhibitors and negatively regulates SPARC expression by targeting mTORC2 in human lung fibroblasts
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DOI：
10.1016/j.pupt.2017.03.003
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发表时间：
2017-06-01
影响因子：
3.2
通讯作者：
Gemma, Akihiko
中科院分区：
文献类型：
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作者：
Kamio, Koichiro;Azuma, Arata;Gemma, Akihiko
特发性肺纤维化（IPF）的发病机制尚不清楚。分泌蛋白（Secreted protein acid and rich in半胱氨酸，SPARC）是一种参与细胞外基质组装和周转的基质蛋白，其表达受转化生长因子(TGF)- β 1通过激活哺乳动物雷帕霉素靶蛋白复合物2 （mTORC2）调控。在血小板、白血病和神经组织中发现的交换因子（XPLN）是一种内源性mTORC2抑制剂。然而，XPLN是否调节SPARC的表达仍然未知。因此，我们研究了XPLN在人肺成纤维细胞中的调控机制。通过使用小干扰RNA沉默人胎儿肺成纤维细胞（HFL-1细胞）中的XPLN，评估XPLN对mTORC2活性的影响。采用实时荧光定量RT-PCR和western blotting检测SPARC的表达。用tgf - β 1、组蛋白去乙酰化酶（HDAC）抑制剂、恩替诺他或伏立诺他处理成纤维细胞，评估其对XPLN表达的影响。此外，我们还研究了mTORC1抑制对SPARC和XPLN的影响。XPLN缺失刺激SPARC表达和Akt磷酸化Ser473。tgf - β 1治疗通过smad2 /3下调XPLN。用HDAC抑制剂治疗后，XPLN mRNA表达呈浓度依赖性上调，而用恩替他治疗后，tgf - β 1诱导的SPARC表达逆转。rapamycin抑制mTORC1和Raptor缺失刺激SPARC表达。总之，这是第一个描述XPLN参与SPARC调控的研究。这些发现可能有助于揭示mTORC2-SPARC轴的调控机制。通过HDAC抑制剂上调XPLN可能是IPF患者的一种新的治疗方法。(C) 2017 Elsevier Ltd.版权所有。
Pathogenesis of idiopathic pulmonary fibrosis (IPF) remains unclear. Secreted protein acidic and rich in cysteine (SPARC) is a matricellular protein that participates in the assembly and turnover of the extra cellular matrix, whose expression is regulated by transforming growth factor (TGF)-beta 1 through activation of mammalian target of rapamycin complex 2 (mTORC2). Exchange factor found in platelets, leukemic, and neuronal tissues (XPLN) is an endogenous inhibitor of mTORC2. However, whether XPLN modulates SPARC expression remains unknown. Herein, we investigated the regulatory mechanisms of XPLN in human lung fibroblasts. Effect of XPLN on mTORC2 activity was evaluated by silencing XPLN in human foetal lung fibroblasts (HFL-1 cells), using small interfering RNA. SPARC expression was quantified by quantitative real-time RT-PCR and western blotting. Fibroblasts were treated with TGF-beta 1, histone deacetylase (HDAC) inhibitors, entinostat, or vorinostat, to assess their effects on XPLN expression. Moreover, the effect of mTORC1 inhibition on SPARC and XPLN was examined. XPLN depletion stimulated SPARC expression and Akt phosphorylation on Ser473. TGF-beta 1 treatment down-regulated XPLN via Smad 2/3. XPLN mRNA expression was up-regulated upon treatment with HDAC inhibitors in a concentration dependent manner, and TGF-beta 1-induced SPARC expression was reversed by entinostat treatment. mTORC1 inhibition by rapamycin and Raptor depletion stimulated SPARC expression. In conclusion, this is the first study describing the involvement of XPLN in the regulation of SPARC. These findings may help uncover the regulatory mechanisms of the mTORC2-SPARC axis. The up-regulation of XPLN by HDAC inhibitors may be a novel therapeutic approach in patients with IPF. (C) 2017 Elsevier Ltd. All rights reserved.