CJUN KINASE (JNK) PATHWAY IN SILICA INDUCED APOPTOSIS

描述：二氧化硅是一种能够诱导成纤维细胞的致纤维化物质。 增殖和过量的胶原蛋白产生，导致一系列 统称为肺纤维化或矽肺的肺部疾病。这个 矽肺发生的关键事件是二氧化硅的相互作用 含肺泡巨噬细胞(AM)的颗粒。矽肺患者的肺泡巨噬细胞 释放肝纤维化因子和细胞因子，包括肿瘤坏死因子-α、白介素1-α 和IL-1β。在体外，可能在体内，用高度的 致纤维化二氧化硅诱导细胞凋亡，而致纤维化作用差的二氧化硅治疗 二氧化硅则不会。首席调查员假设这一点 细胞凋亡依赖于JNK/SAPK信号通路的激活 部分通过包括IL-1α和IL-1β在内的促炎细胞因子，以及 激活JNK使转录因子磷酸化，从而导致 诱导细胞凋亡。调查者进一步假设，定义 抑制细胞凋亡信号通路可能提供新的治疗方法 防治二氧化硅所致肺损伤的策略。她的三个具体目标测试 在培养的单核细胞系、人外周血中存在这一假说 单核细胞、人肺泡巨噬细胞、石蜡包埋的人肺组织和正常人 和基因敲除老鼠。 特异性目标1将探讨JNK通路在二氧化硅诱导中的作用 通过体外研究进行细胞凋亡。调查员将首先确定 二氧化硅体外诱导JNK活化和凋亡的动力学； 探讨促炎细胞因子IL-1β和肿瘤坏死因子-α的作用 在这些回应中。JNK激活与细胞凋亡的关系将是 在JNK活性被抑制的转染体中进行的研究 显性-负性上游信号分子(MEKK1、SEK、 JNK)或可能通过PAK样激酶的过表达而激活， HPK1。 《特殊目的2》将调查细胞凋亡与矽肺的关系 矽肺患者肺组织石蜡切片的活体研究 并通过在正常小鼠和IL-1βKO小鼠中的进一步研究。 特定目标3将寻找半胱氨酸蛋白酶的抑制剂和清除剂 在体外可以阻断JNK激活和凋亡的受体。成功 化合物将在小鼠体内进行测试，以确定它们是否有能力减弱或 逆转二氧化硅诱导的肺损伤。

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.