Externally applied pressure activates pancreatic stellate cells through the generation of intracellular reactive oxygen species
Externally applied pressure activates pancreatic stellate cells through the generation of intracellular reactive oxygen species
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DOI：
10.1152/ajpgi.00018.2007
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发表时间：
2007-11-01
影响因子：
4.5
通讯作者：
Otsuki, Makoto
中科院分区：
文献类型：
--
作者：
Asaumi, Hiroshi;Watanabe, Shiro;Otsuki, Makoto
慢性胰腺炎局部组织压力高于正常胰腺。我们近期报道，压力作用可诱导胰腺星状细胞（PSCs）合成细胞外基质（ECM）和细胞因子，而表没食子儿茶素没食子酸酯（EGCG）这种强效抗氧化剂可抑制PSCs从静止表型向活化表型的转化以及乙醇诱导的PSCs中ECM和细胞因子的合成。这些结果表明氧化应激和活性氧物质（ROS）在PSCs活化中起重要作用。本研究旨在阐明ROS对压力刺激的PSCs活化及功能的影响。我们使用新鲜分离的大鼠PSCs和培养活化的PSCs。通过向压力加载装置中加入压缩氦气对大鼠培养的PSCs施加压力。在正常压力或高压下，PSCs在有或无抗氧化剂（EGCG和N - 乙酰半胱氨酸）的条件下培养。外部施加高压（80 mmHg）导致PSCs中超氧化物歧化酶活性逐渐降低，并且早在30秒时细胞内ROS产生就增加，在1小时达到峰值。抗氧化剂显著抑制ROS产生。压力增加了PSCs中α - 平滑肌肌动蛋白、α(1)(I) - 前胶原和转化生长因子 - β1的表达水平。EGCG抑制了这些改变，消除了压力诱导的p38丝裂原活化蛋白激酶的磷酸化，并抑制了压力诱导的PSCs向活化表型的转化。我们的结果表明，ROS是压力诱导的PSCs活化和ECM合成的关键因素。抗氧化剂可能对慢性胰腺炎患者胰腺纤维化的发展具有潜在的治疗作用。
Local tissue pressure is higher in chronic pancreatitis than in the normal pancreas. We reported recently that pressure application induces synthesis of extracellular matrix ( ECM) and cytokines in pancreatic stellate cells ( PSCs) and that epigallocatechin gallate ( EGCG), a potent antioxidant, inhibits the transformation of PSCs from quiescent to activated phenotype and ethanol- induced synthesis of ECM and cytokines in PSCs. These results suggest that oxidative stress and reactive oxygen species ( ROS) are important in PSC activation. The aim of this study was to clarify the effects of ROS on activation and functions of pressure- stimulated PSCs. We used freshly isolated rat PSCs and culture- activated PSCs. Pressure was applied on rat cultured PSCs by adding compressed helium gas into a pressure- loading apparatus. PSCs were cultured with or without antioxidants ( EGCG and N- acetyl cysteine) under normal or elevated pressure. Externally applied high pressure ( 80 mmHg) resulted in a gradual decrease of superoxide dismutase activity in PSCs and increased intracellular ROS generation as early as 30 s, reaching a peak level at 1 h. Antioxidants significantly inhibited ROS generation. Pressure increased the expression levels of alpha- smooth muscle actin, alpha(1)(I)- procollagen, and TGF-beta 1 in PSCs. EGCG suppressed these alterations, abolished pressure- induced phosphorylation of p38 MAPK, and suppressed pressure- induced PSC transformation to activated phenotype. Our results indicated that ROS is a key player in pressure- induced PSC activation and ECM synthesis. Antioxidants could be potentially effective against the development of pancreatic fibrosis in patients with chronic pancreatitis.