Gallic Acid Induces Apoptosis of Lung Fibroblasts via a Reactive Oxygen Species-Dependent Ataxia Telangiectasia Mutated-p53 Activation Pathway
Gallic Acid Induces Apoptosis of Lung Fibroblasts via a Reactive Oxygen Species-Dependent Ataxia Telangiectasia Mutated-p53 Activation Pathway
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DOI：
10.1021/jf9043265
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发表时间：
2010-03-10
影响因子：
6.1
通讯作者：
Hsu, Shih-Lan
中科院分区：
文献类型：
--
作者：
Chuang, Cheng-Yen;Liu, Hsiang-Chun;Hsu, Shih-Lan
特发性肺纤维化（IPF）是一种进行性慢性疾病，其特征是成纤维细胞的激活和细胞外基质的过量产生。成纤维细胞对凋亡的抵抗导致纤维化增加。用凋亡药物靶向成纤维细胞是削弱IPF的主要治疗干预措施。没食子酸（3,4,5-三羟基苯甲酸）是一种天然存在的植物酚，据报道可诱导肿瘤细胞系和肾成纤维细胞凋亡。然而，没食子酸对肺成纤维细胞的影响尚未被研究。本研究的目的是确定没食子酸对原代培养小鼠成纤维细胞的影响。我们的研究结果表明，没食子酸通过提高PUMA、Fas和FasL蛋白水平，通过内源性和外源性凋亡途径诱导成纤维细胞凋亡。此外，在没食子酸刺激的成纤维细胞中观察到细胞内活性氧（ROS）的产生和8-羟基-2'-脱氧鸟苷的产生。机制研究表明，在ros引起的DNA损伤中，没食子酸通过ataxia毛细血管扩张突变（ATM）激活诱导p53（Ser18）和组蛋白2AX(Ser139) （H2AX）的早期磷酸化。当用咖啡因（一种ATM激酶抑制剂）处理小鼠肺成纤维细胞时，p53、磷酸化p53（Ser18）的水平和没食子酸诱导的细胞死亡水平显著降低。此外，抗氧化剂预处理能显著抑制没食子酸诱导的8-羟基-2′-脱氧鸟苷（8-OH-dG）的形成、p53（Ser18）和ATM（Ser1981）的磷酸化以及细胞凋亡。我们的研究结果首次证明ros依赖性ATM/p53信号的激活是未食子酸诱导的原代培养小鼠肺成纤维细胞死亡的关键机制。
Idiopathic pulmonary fibrosis (IPF) is a progressive chronic disorder characterized by the activation of fibroblasts and the overproduction of extracellular matrix. Fibroblast resistance to apoptosis leads to increased fibrosis. Targeting fibroblasts with apoptotic agents represents a major therapeutic intervention for debilitating IPF. Gallic acid (3,4,5-trihydroxybenzoic acid), a naturally occurring plant phenol, has been reported to induce apoptosis in tumor cell lines and renal fibroblasts. However, the effects of gallic acid on lung fibroblasts have not been investigated. The aim of the present study is to determine the effects of gallic acid on primary cultured mouse fibroblasts. Our results showed that gallic acid induces the apoptotic death of fibroblasts via both intrinsic and extrinsic apoptotic pathways by the elevation of PUMA, Fas, and FasL protein levels. Moreover, intracellular reactive oxygen species (ROS) generation and 8-hydroxy-2'-deoxyguanosine production were observed in gallic acid-stimulated fibroblasts. Mechanistic studies showed that gallic acid induces early phosphorylation of p53(Ser18) and histone 2AX(Ser139) (H2AX) via ataxia telangiectasia mutated (ATM) activation in response to ROS-provoked DNA damage. When mouse lung fibroblasts were treated with caffeine, an ATM kinase inhibitor, the levels of p53, phosphorylated p53(Ser18), and cell death induced by gallic acid were significantly attenuated. Additionally, pretreatment with antioxidants drastically inhibited the gallic acid-induced 8-hydroxy-2'-deoxyguanosine (8-OH-dG) formation and phosphorylation of p53(Ser18) and ATM(Ser1981), as well as apoptosis. Our results provide the first evidence of the activation of ROS-dependent ATM/p53 signaling as a critical mechanism of gallic acid-induced cell death in primary cultured mouse lung fibroblasts.