EGFR SIGNALING PATHWAYS BY PARTICULATES IN LUNG DISEASE

肺上皮细胞和胸膜间皮细胞是主要的 包括石棉在内的吸入环境颗粒物的目标 纤维和颗粒物（PM）。将这些细胞类型暴露于 石棉或PM导致早期的表达增加 反应prot（o）癌基因，c-jun和c-fos，它们与 在其它细胞类型中发生凋亡和/或增殖。 最近，我们已经表明，石棉纤维，相比之下， 非致病性颗粒的数量，刺激细胞外 信号相关激酶（ERK）级联，即促分裂原活化蛋白 激酶（MAPK），通过涉及自磷酸化的机制 表皮生长因子受体（EGFR）在这一提议中， 我们将检验假设（#1），即EGFR的激活是由 石棉纤维调节ERK细胞信号通路， 大鼠胸膜间皮瘤（RPM）和大鼠胸膜间皮瘤细胞凋亡的发生 肺泡II型上皮（RLE）细胞。第二个假设是 测试的是，EGFR表达在发展中发挥作用， 上皮细胞凋亡，一种可能的修复机制， II型上皮细胞增殖和肺纤维化 吸入石棉后为了验证这些假设， EGFR的磷酸化，ERK的活化与c-Jun氨基末端 将在RPM中检查JNK、凋亡和增殖 添加温石棉或青石棉后的体外RLE 存在和不存在EGFR选择性抑制剂时的石棉 在使用显性负性EGFR突变体的转染实验中， 结构。转基因小鼠过表达显性负突变体 使用肺上皮细胞特异性启动子的体内EGFR也将 通过吸入暴露于石棉，并使用 细胞增殖、凋亡和凋亡的定量标志物， 纤维化，以确定这些结果的严重程度和范围 与转基因阴性窝仔相比， 伙计们结果将表明EGFR受体活化和细胞凋亡是否与EGFR受体活化有关。 MAPK信号级联是上皮细胞损伤的内在因素， 吸入外源性物质导致的肺部疾病， 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.