Pacurari M, May I, Tchounwou P B
Biology Department, College of Science, Engineering, and Technology, Jackson State University, Jackson, MS, 39217.
NIH RCMI-Center for Environmental Health, College of Science, Engineering, and Technology, Jackson State University, Jackson, MS, 39217.
Environ Toxicol. 2017 Feb;32(2):445-455. doi: 10.1002/tox.22248. Epub 2016 Feb 16.
Multiwalled carbon nanotubes (MWCNT) have been shown to induce lung fibrosis in animal models, however the underlying molecular factors/mechanisms are still unclear. In this study, we investigated the effects of lipopolysaccharide (LPS), MWCNT, and the combination of LPS and MWCNT on the expression of matrix metalloproteinase-9 and metalloproteinase-12 (MMP-9, MMP-12), collagen 3A1 (Col3A1), and transforming growth factor beta (TGFβ) in alveolar epithelial A549 cells. MMPs are proteinases that degrade extracellular matrix and play a role in lung fibrosis. A549 cells were exposed to LPS (1 ng/mL), MWCNT (20 μg/mL), and the combination and analyzed for paracellular permeability, TGFβ, Col3A1, MMP-9, MMP-12, NF-κB activation, and cell migration by real-time PCR and immunofluorescence. LPS, the combination of LPS and MWCNT, and MWCNT only at the highest tested dose induced blue dextran extravasation. LPS and MWCNT increased the expression of TGFβ and its downstream target gene Col3A, and MMP-9 and MMP-12 mRNA. MWCNT potently induced cell migration toward wound healing, whereas LPS slightly induced cell migration. Both, LPS and MWCNT, induced NF-κB nuclear translocation. Our results indicate that MWCNT activated alveolar epithelial cells to promote fibrogenesis, and that LPS differentially primes molecular factors involved in lung remodeling. These findings suggest a role of alveolar epithelial cells in fibrogenesis and also may aid in the design and development of tests for screening of fibrogenic agents. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 445-455, 2017.
多壁碳纳米管（MWCNT）已被证明可在动物模型中诱发肺纤维化，但其潜在的分子因素/机制仍不清楚。在本研究中，我们调查了脂多糖（LPS）、MWCNT以及LPS与MWCNT联合作用对肺泡上皮A549细胞中基质金属蛋白酶-9和金属蛋白酶-12（MMP-9、MMP-12）、胶原蛋白3A1（Col3A1）和转化生长因子β（TGFβ）表达的影响。基质金属蛋白酶是降解细胞外基质并在肺纤维化中起作用的蛋白酶。将A549细胞暴露于LPS（1 ng/mL）、MWCNT（20 μg/mL）及其组合中，并通过实时聚合酶链反应和免疫荧光分析细胞旁通透性、TGFβ、Col3A1、MMP-9、MMP-12、核因子κB（NF-κB）激活和细胞迁移情况。LPS、LPS与MWCNT的组合以及仅在最高测试剂量下的MWCNT均诱导了蓝色葡聚糖外渗。LPS和MWCNT增加了TGFβ及其下游靶基因Col3A以及MMP-9和MMP-12 mRNA的表达。MWCNT有力地诱导细胞向伤口愈合方向迁移，而LPS轻微诱导细胞迁移。LPS和MWCNT均诱导了NF-κB核转位。我们的结果表明，MWCNT激活肺泡上皮细胞以促进纤维化形成，并且LPS差异地引发参与肺重塑过程的分子因子。这些发现提示肺泡上皮细胞在纤维化形成中发挥作用，也可能有助于设计和开发用于筛选致纤维化剂的检测方法。© 2016威利期刊公司。《环境毒理学》32:445 - 455，2017年。
