Abstract

Background

Per- and polyfluoroalkyl substances (PFAS) have been associated with respiratory diseases in humans, yet the mechanisms through which PFAS cause susceptibility to inhaled agents is unknown. Herein, we investigated the effects of ammonium perfluoro(2-methyl-3-oxahexanoate) (GenX), an emerging PFAS, on the pulmonary immune response of mice to carbon black nanoparticles (CBNP). We hypothesized that pulmonary exposure to GenX would increase susceptibility to CBNP through suppression of innate immunity.

Methods

Male C57BL/6 mice were exposed to vehicle, 4 mg/kg CBNP, 10 mg/kg GenX, or CBNP and GenX by oropharyngeal aspiration. Bronchoalveolar lavage fluid (BALF) was collected at 1 and 14 days postexposure for cytokines and total protein. Lung tissue was harvested for histopathology, immunohistochemistry (Ki67 and phosphorylated (p)-STAT3), western blotting (p-STAT3 and p-NF-κB), and qRT-PCR for cytokine mRNAs.

Results

CBNP increased CXCL-1 and neutrophils in BALF at both time points evaluated. However, GenX/CBNP co-exposure reduced CBNP-induced CXCL-1 and neutrophils in BALF. Moreover, CXCL-1, CXCL-2 and IL-1β mRNAs were increased by CBNP in lung tissue but reduced by GenX. Western blotting showed that CBNP induced p-NF-κB in lung tissue, while the GenX/CBNP co-exposed group displayed decreased p-NF-κB. Furthermore, mice exposed to GenX or GenX/CBNP displayed increased numbers of BALF macrophages undergoing mitosis and increased Ki67 immunostaining. This was correlated with increased p-STAT3 by western blotting and immunohistochemistry in lung tissue from mice co-exposed to GenX/CBNP.

Conclusions

Pulmonary exposure to GenX suppressed CBNP-induced innate immune response in the lungs of mice yet promoted the proliferation of macrophages and lung epithelial cells.

中文翻译：

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小鼠肺部暴露于全氟（2-甲基-3-氧六环己酸）铵 (GenX) 会抑制对炭黑纳米颗粒的先天免疫反应并刺激肺细胞增殖

摘要

背景

全氟和多氟烷基物质 (PFAS) 与人类呼吸系统疾病有关，但 PFAS 引起对吸入剂易感性的机制尚不清楚。在此，我们研究了全氟（2-甲基-3-氧杂己酸）铵 (GenX)（一种新兴的 PFAS）对小鼠对炭黑纳米颗粒 (CBNP) 的肺部免疫反应的影响。我们假设肺部暴露于 GenX 会通过抑制先天免疫来增加对 CBNP 的易感性。

方法

雄性 C57BL/6 小鼠通过口咽吸入暴露于载体、4 mg/kg CBNP、10 mg/kg GenX 或 CBNP 和 GenX。在暴露后 1 天和 14 天收集支气管肺泡灌洗液 (BALF) 的细胞因子和总蛋白。收集肺组织用于组织病理学、免疫组织化学（Ki67 和磷酸化 (p)-STAT3）、蛋白质印迹（p-STAT3 和 p-NF-κB）和细胞因子 mRNA 的 qRT-PCR。

结果

CBNP 在评估的两个时间点都增加了 BALF 中的 CXCL-1 和中性粒细胞。然而，GenX/CBNP 共同暴露减少了 BALF 中 CBNP 诱导的 CXCL-1 和中性粒细胞。此外，肺组织中的 CXCL-1、CXCL-2 和 IL-1β mRNA 被 CBNP 增加，但被 GenX 减少。蛋白质印迹显示 CBNP 在肺组织中诱导 p-NF-κB，而 GenX/CBNP 共暴露组显示 p-NF-κB 降低。此外，暴露于 GenX 或 GenX/CBNP 的小鼠显示出经历有丝分裂的 BALF 巨噬细胞数量增加，并且 Ki67 免疫染色增加。这与共暴露于 GenX/CBNP 的小鼠肺组织中通过蛋白质印迹和免疫组织化学检测的 p-STAT3 增加相关。

结论

肺暴露于 GenX 抑制了小鼠肺部 CBNP 诱导的先天免疫反应，但促进了巨噬细胞和肺上皮细胞的增殖。