CJUN KINASE (JNK) PATHWAY IN SILICA INDUCED APOPTOSIS

描述：二氧化硅是一种纤维化剂，能够诱导成纤维细胞 增殖和过量的胶原蛋白产生，导致一系列的 肺部疾病统称为肺纤维化或硅肺。 的 矽肺发生的关键事件是二氧化硅 颗粒与肺泡巨噬细胞（AM）。 矽肺患者AM 释放纤维化因子和细胞因子，包括TNF-α、IL-1 α 和IL-1 β。 在体外，并且可能在体内，用高浓度的 致纤维化二氧化硅诱导细胞凋亡，而用致纤维化性差的二氧化硅治疗 而二氧化硅则不然。 首席研究员假设， 细胞凋亡依赖于JNK/SAPK信号通路的激活，介导 部分通过促炎细胞因子包括IL-1 α和IL-1 β，和 激活的JNK磷酸化转录因子， 诱导细胞凋亡。 研究人员进一步假设， 抑制细胞凋亡信号通路可能提供新的治疗方法 预防二氧化硅引起的肺损伤的策略。 她的三个具体目标测试 在培养的单核细胞系、人外周血 单核细胞、来自人BAL的AM、石蜡包埋的人肺组织和正常人 和敲除小鼠。 具体目标1将探索JNK通路在二氧化硅诱导的细胞凋亡中的作用。 通过体外研究发现细胞凋亡。 调查员将首先确定 体外二氧化硅诱导的JNK活化和细胞凋亡的动力学;以及 探讨促炎细胞因子IL-1 β和TNF-α的作用 在这些回应中。 JNK激活与细胞凋亡的关系将在 在JNK激活被抑制的转染子中研究， 引入显性负向上游信号分子（MEKK 1，SEK， JNK）或可能被PAK样激酶的过表达激活， HPK1. 具体目标2将探讨细胞凋亡与矽肺的关系 通过对矽肺患者肺石蜡切片的研究 并通过在正常和IL-1 β KO小鼠中的进一步研究。 具体目标3将寻找半胱氨酸蛋白酶和清除剂的抑制剂 受体，可以在体外阻断JNK激活和凋亡。 成功 化合物将在小鼠体内测试它们减弱或 逆转二氧化硅引起的肺损伤。

DESCRIPTION: Silica is a fibrogenic agent capable of inducing fibroblast proliferation and excess collagen production, causing a spectrum of pulmonary diseases known collectively as lung fibrosis or silicosis. The key event in the genesis of silicosis is the interaction of the silica particle with alveolar macrophages (AM). AMs from silicotic patients release fibrogenic factors and cytokines, including TNF-alpha, IL-1 alpha and IL-1 beta. In vitro, and probably in vivo, treatment of AMs with highly fibrogenic silica induces apoptosis whereas treatment with poorly fibrogenic silica does not. The principal investigator hypothesizes that this apoptosis depends on activation of the JNK/SAPK signaling pathway, mediated in part by proinflammatory cytokines including IL-1 alpha and IL-1 beta, and that activated JNK phosphorylates transcription factors leading to the induction of apoptosis. The investigator further hypothesizes that defining and inhibiting the apoptotic signaling pathway may provide new therapeutic strategies against silica-induced lung injury. Her three specific aims test this hypothesis in cultured monocytic cell lines, human peripheral blood monocytes, AM from human BAL, paraffin-embedded human lung tissue and normal and knockout mice. Specific aim 1 will explore the role of the JNK pathway in silica-induced apoptosis through in vitro studies. The investigator will first determine the kinetics of silica-induced JNK activation and apoptosis in vitro; and explore the roles of the proinflammatory cytokines IL-1 beta and TNF-alpha in these responses. The relationship of JNK activation to apoptosis will be studied in transfectants where JNK activation is inhibited by the introduction of dominant-negative upstream signaling molecules (MEKK1, SEK, JNK) or potentially activated by overexpression of the PAK-like kinase, HPK1. Specific aim 2 will investigate the association of apoptosis with silicosis in vivo through studies of paraffin sections of lung from silicotic patients and through further studies in the normal and IL-1 beta KO mice. Specific aim 3 will look for inhibitors of cysteine proteases and scavenger receptors that can block JNK activation and apoptosis in vitro. Successful compounds will be tested in vivo in mice for their ability to attenuate or reverse silica-induced lung injury.