Department of Biological Sciences, Idaho State University, Pocatello, ID 83209, USA.
J Immunotoxicol. 2011 Jun;8(2):159-69. doi: 10.3109/1547691X.2011.562257. Epub 2011 Apr 4.
Pulmonary fibrosis is a relentlessly progressive disease for which the etiology can be idiopathic or associated with environmental or occupational exposures. There is not a clear explanation for the chronic and progressive nature of the disease, leaving treatment and prevention options limited. However, there is increasing evidence of an autoimmune component, since fibrotic diseases are often accompanied by production of autoantibodies. Because exposure to silicates such as silica and asbestos can lead to both autoantibodies and pulmonary/pleural fibrosis, these exposures provide an excellent tool for examining the relationship between these outcomes. This study explored the possibility that autoantibodies induced by asbestos exposure in mice would affect fibroblast phenotype. L929 fibroblasts and primary lung fibroblasts were treated with serum IgG from asbestos- or saline-treated mice, and tested for binding using cell-based ELISA, and for phenotypic changes using immunofluorescence, laser scanning cytometry and Sirius Red collagen assay. Autoantibodies in the serum of C57Bl/6 mice exposed to asbestos (but not sera from untreated mice) bound to mouse fibroblasts. The autoantibodies induced differentiation to a myofibroblast phenotype, as demonstrated by increased expression of smooth muscle α-actin (SMA), which was lost when the serum was cleared of IgG. Cells treated with purified IgG of exposed mice produced excess collagen. Using ELISA, we tested serum antibody binding to DNA topoisomerase (Topo) I, vimentin, TGFβ-R, and PDGF-Rα. Antibodies to DNA Topo I and to PDGF-Rα were detected, both of which have been shown by others to be able to affect fibroblast phenotype. The anti-fibroblast antibodies (AFA) also induced STAT-1 activation, implicating the PDGF-R pathway as part of the response to AFA binding. These data support the hypothesis that asbestos induces AFA that modify fibroblast phenotype, and suggest a mechanism whereby autoantibodies may mediate some of the fibrotic manifestations of asbestos exposure.
肺纤维化是一种进行性疾病，其病因可为特发性或与环境或职业暴露有关。目前对于这种疾病的慢性和进行性特征还没有明确的解释，这使得治疗和预防方法有限。然而，越来越多的证据表明存在自身免疫成分，因为纤维化疾病通常伴随着自身抗体的产生。由于暴露于硅石如二氧化硅和石棉等物质会导致自身抗体和肺/胸膜纤维化，因此这些暴露为研究这些结果之间的关系提供了极好的工具。本研究探讨了石棉暴露诱导的小鼠自身抗体是否会影响成纤维细胞表型的可能性。用来自于经石棉或盐水处理的小鼠的血清 IgG 处理 L929 成纤维细胞和原代肺成纤维细胞，并通过基于细胞的 ELISA 检测结合，通过免疫荧光、激光扫描共聚焦和 Sirius Red 胶原测定检测表型变化。暴露于石棉的 C57Bl/6 小鼠血清中的自身抗体（但不是未经处理的小鼠血清）与小鼠成纤维细胞结合。自身抗体诱导向肌成纤维细胞表型分化，这表现为平滑肌肌动蛋白（SMA）表达增加，当血清中 IgG 被清除时，这种表型分化会丢失。用暴露小鼠的纯化 IgG 处理的细胞产生过多的胶原。我们使用 ELISA 测试了血清抗体与 DNA 拓扑异构酶（Topo）I、波形蛋白、TGFβ-R 和 PDGF-Rα 的结合。检测到针对 DNA Topo I 和 PDGF-Rα 的抗体，其他人已经表明这两种抗体都能够影响成纤维细胞表型。抗成纤维细胞抗体（AFA）还诱导 STAT-1 激活，这表明 PDGF-R 途径是 AFA 结合反应的一部分。这些数据支持了这样的假设，即石棉诱导的 AFA 改变了成纤维细胞表型，并提出了一种机制，即自身抗体可能介导石棉暴露的一些纤维化表现。
