Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
Toxicol Appl Pharmacol. 2013 Oct 15;272(2):476-89. doi: 10.1016/j.taap.2013.06.026. Epub 2013 Jul 8.
The fibrous shape and biopersistence of multi-walled carbon nanotubes (MWCNT) have raised concern over their potential toxicity after pulmonary exposure. As in vivo exposure to MWCNT produced a transient inflammatory and progressive fibrotic response, this study sought to identify significant biological processes associated with lung inflammation and fibrosis pathology data, based upon whole genome mRNA expression, bronchoaveolar lavage scores, and morphometric analysis from C57BL/6J mice exposed by pharyngeal aspiration to 0, 10, 20, 40, or 80 μg MWCNT at 1, 7, 28, or 56 days post-exposure. Using a novel computational model employing non-negative matrix factorization and Monte Carlo Markov Chain simulation, significant biological processes with expression similar to MWCNT-induced lung inflammation and fibrosis pathology data in mice were identified. A subset of genes in these processes was determined to be functionally related to either fibrosis or inflammation by Ingenuity Pathway Analysis and was used to determine potential significant signaling cascades. Two genes determined to be functionally related to inflammation and fibrosis, vascular endothelial growth factor A (vegfa) and C-C motif chemokine 2 (ccl2), were confirmed by in vitro studies of mRNA and protein expression in small airway epithelial cells exposed to MWCNT as concordant with in vivo expression. This study identified that the novel computational model was sufficient to determine biological processes strongly associated with the pathology of lung inflammation and fibrosis and could identify potential toxicity signaling pathways and mechanisms of MWCNT exposure which could be used for future animal studies to support human risk assessment and intervention efforts.
多壁碳纳米管（MWCNT）的纤维状形状和生物持久性引起了人们对其在肺部暴露后潜在毒性的关注。由于体内暴露于 MWCNT 会产生短暂的炎症和进行性纤维化反应，因此本研究试图根据 C57BL/6J 小鼠的全基因组 mRNA 表达、支气管肺泡灌洗评分和形态计量分析，确定与肺部炎症和纤维化病理数据相关的重要生物学过程，这些小鼠通过咽吸入暴露于 0、10、20、40 或 80μg MWCNT 后，在 1、7、28 或 56 天进行检测。本研究采用一种新的计算模型，运用非负矩阵分解和蒙特卡罗马尔可夫链模拟，确定了与 MWCNT 诱导的小鼠肺部炎症和纤维化病理数据具有相似表达的重要生物学过程。通过对这些过程中的一部分基因进行分析，发现它们与纤维化或炎症功能相关，通过 Ingenuity Pathway Analysis 确定了潜在的重要信号通路。通过对暴露于 MWCNT 的小气道上皮细胞的 mRNA 和蛋白表达进行体外研究，确定了两个与炎症和纤维化功能相关的基因，即血管内皮生长因子 A（vegfa）和 C-C 基序趋化因子 2（ccl2），这两个基因与体内表达一致。本研究表明，新型计算模型足以确定与肺部炎症和纤维化病理密切相关的生物学过程，并能够识别 MWCNT 暴露的潜在毒性信号通路和机制，可用于未来的动物研究，为人类风险评估和干预措施提供支持。
