Department of Epidemiology and Population Health, School of Public Health and Information Sciences, University of Louisville, Louisville, KY, USA.
Indiana University School of Medicine, Indianapolis, IN, USA.
Nanotoxicology. 2024 Sep;18(6):565-581. doi: 10.1080/17435390.2024.2404074. Epub 2024 Sep 19.
We have previously demonstrated that exposure to cobalt nanoparticles (Nano-Co) caused extensive interstitial fibrosis and inflammatory cell infiltration in mouse lungs. However, the underlying mechanisms of Nano-Co-induced pulmonary fibrosis remain unclear. In this study, we investigated the role of high-mobility group box 1 (HMGB1) in the epithelial cell-fibroblast crosstalk in Nano-Co-induced pulmonary fibrosis. Our results showed that Nano-Co exposure caused remarkable production and release of HMGB1, as well as nuclear accumulation of HIF-1α in human bronchial epithelial cells (BEAS-2B) in a dose- and a time-dependent manner. Pretreatment with CAY10585, an inhibitor against HIF-1α, significantly blocked the overexpression of HMGB1 in cell lysate and the release of HMGB1 in the supernatant of BEAS-2B cells induced by Nano-Co exposure, indicating that Nano-Co exposure induces HIF-1α-dependent HMGB1 overexpression and release. In addition, treatment of lung fibroblasts (MRC-5) with conditioned media from Nano-Co-exposed BEAS-2B cells caused increased RAGE expression, MAPK signaling activation, and enhanced expression of fibrosis-associated proteins, such as fibronectin, collagen 1, and α-SMA. However, conditioned media from Nano-Co-exposed BEAS-2B cells with HMGB1 knockdown had no effects on the activation of MRC-5 fibroblasts. Finally, inhibition of ERK1/2, p38, and JNK all abolished MRC-5 activation induced by conditioned media from Nano-Co-exposed BEAS-2B cells, suggesting that MAPK signaling might be a key downstream signal of HMGB1/RAGE to promote MRC-5 fibroblast activation. These findings have important implications for understanding the pro-fibrotic potential of Nano-Co.
我们之前已经证明，暴露于钴纳米颗粒（Nano-Co）会导致小鼠肺部广泛的间质纤维化和炎症细胞浸润。然而，Nano-Co 诱导肺纤维化的潜在机制尚不清楚。在这项研究中，我们研究了高迁移率族蛋白 1（HMGB1）在 Nano-Co 诱导的肺纤维化中上皮细胞-成纤维细胞串扰中的作用。我们的结果表明，Nano-Co 暴露以剂量和时间依赖的方式引起人支气管上皮细胞（BEAS-2B）中 HMGB1 的大量产生和释放，以及 HIF-1α的核积累。用 CAY10585（一种针对 HIF-1α的抑制剂）预处理，可显著阻断 Nano-Co 暴露诱导的 BEAS-2B 细胞中细胞裂解物中 HMGB1 的过度表达和上清液中 HMGB1 的释放，表明 Nano-Co 暴露诱导 HIF-1α依赖性 HMGB1 过度表达和释放。此外，用暴露于 Nano-Co 的 BEAS-2B 细胞的条件培养基处理肺成纤维细胞（MRC-5），导致 RAGE 表达增加，MAPK 信号通路激活，并增强纤维化相关蛋白，如纤维连接蛋白、胶原 1 和 α-SMA 的表达。然而，用 HMGB1 敲低的 Nano-Co 暴露的 BEAS-2B 细胞的条件培养基对 MRC-5 成纤维细胞的激活没有影响。最后，抑制 ERK1/2、p38 和 JNK 均可消除暴露于 Nano-Co 的 BEAS-2B 细胞的条件培养基诱导的 MRC-5 激活，表明 MAPK 信号通路可能是 HMGB1/RAGE 促进 MRC-5 成纤维细胞激活的关键下游信号。这些发现对理解 Nano-Co 的促纤维化潜力具有重要意义。
