EGFR SIGNALING PATHWAYS BY PARTICULATES IN LUNG DISEASE

肺上皮和胸膜间皮细胞是主要的 包括石棉在内的可吸入环境颗粒物的指标 纤维和颗粒物(PM)。这些类型的细胞暴露在 石棉或PM导致早期基因表达增加 应答蛋白(O)癌基因c-jun和c-fos，它们与 在其他类型的细胞中发生凋亡和/或增殖。 最近，我们已经表明，石棉纤维与 非致病粒子的数量，刺激细胞外 信号相关蛋白(ERK)级联，即丝裂原激活蛋白 激酶(MAPK)，通过一种涉及自动磷酸化的机制 表皮生长因子受体(EGFR)。在这份提案中， 我们将检验假设(#1)，即通过 石棉纤维调节ERK细胞信号通路 大鼠胸膜间皮细胞和大鼠胸膜间皮细胞凋亡的研究进展 肺泡II型上皮(RLE)细胞。第二个假设是 试验表明，EGFR的表达在血管内皮细胞瘤的发生发展中发挥了作用。 上皮细胞凋亡--一种可能的去除修复机制 增殖的II型上皮细胞与肺纤维化 在吸入石棉后。为了验证这些假设， EGFR的磷酸化、ERKs的激活与c-jun氨基末端的比较 在RPM中将检测到激酶(JNKs)、细胞凋亡和增殖 和加入温石棉或青石棉后的RLE 存在和不存在选择性EGFR抑制剂时的石棉 并在使用显性阴性EGFR突变体的转染实验中 构造。过表达显性负突变的转基因小鼠 在体内使用肺上皮细胞特异性启动子的EGFR也将 通过吸入石棉而暴露于石棉中，并使用 细胞增殖、凋亡的定量标记物 纤维化，以确定这些结果的严重性和程度 与转基因阴性垃圾相比发生了显著的变化 伙计们。结果将表明，如果EGFR受体激活和 MAPK信号转导通路是上皮细胞损伤的内在机制 由吸入异物引起的肺部疾病，并导致 人类的治疗策略。

Pulmonary epithelial and pleural mesothelial cells are primary targets of inhaled environmental particulates including asbestos fibers and particulate matter (PM). Exposure of these cell types to asbestos or PM leads to increases in expression of the early response prot(o)oncogenes, c-jun and c-fos, which are linked to the development of apoptosis and/or proliferation in other cell types. Recently, we have shown that asbestos fibers, in contrast to a number of nonpathogenic particles, stimulate the Extracellular Signal-Related Kinase (ERK) cascade, i.e. Mitogen-Activated Protein Kinase (MAPK) , through a mechanism involving autophosphorylation of the Epidermal Growth Factor Receptor (EGFR). In this proposal, we will test the hypothesis (#1) that activation of the EGFR by asbestos fibers modulates the ERK cell signalling pathway and the development of apoptosis in rat pleural mesothelial (RPM) and rat alveolar type II epithelial (RLE) cells. A second hypothesis to be tested is that EGFR expression plays a role in the development of epithelial cell apoptosis, a possible repair mechanism in removal of proliferating type II epithelial cells, and pulmonary fibrosis after inhalation of asbestos. To verify these hypotheses, phosphorylation of EGFR, activation of ERKs vs. c-Jun amino terminal kinases (JNKs), apoptosis and proliferation will be examined in RPM and RLE in vitro after addition of chrysotile or crocidolite asbestos in the presence and absence of selective inhibitors of EGFR and in transfection experiments using dominant negative EGFR mutant constructs. Transgenic mice overexpressing dominant negative mutant EGFR in vivo using lung epithelial-cell specific promoters also will be exposed by inhalation to asbestos and characterized, using quantitative markers for cell proliferation, apoptosis, and fibrosis, to determine if the severity and extent of these outcomes are altered significantly in comparison to transgene-negative litter mates. Results will indicate if EGFR receptor activation and the MAPK signalling cascade are intrinsic to epithelial cell injury and lung disease by inhaled xenobiotics and lead to the development of therapeutic strategies in man.