The mechanisms driving systemic effects consequent pulmonary nanoparticle exposure remain unclear. Recent work has established the existence of an indirect process by which factors released from the lung into the circulation promote systemic inflammation and cellular dysfunction, particularly on the vasculature. However, the composition of circulating contributing factors and how they are produced remains unknown. Evidence suggests matrix protease involvement; thus, here we used a well-characterized multi-walled carbon nanotube (MWCNT) oropharyngeal aspiration model with known vascular effects to assess the distinct contribution of nanoparticle-induced peptide fragments in driving systemic pathobiology. Data-independent mass spectrometry enabled the unbiased quantitative characterization of 841 significant MWCNT-responses within an enriched peptide fraction, with 567 of these factors demonstrating significant correlation across animal-paired bronchoalveolar lavage and serum biofluids. A database search curated for known matrix protease substrates and predicted signaling motifs enabled identification of 73 MWCNT-responsive peptides, which were significantly associated with an abnormal cardiovascular phenotype, extracellular matrix organization, immune-inflammatory processes, cell receptor signaling, and a MWCNT-altered serum exosome population. Production of a diverse peptidomic response was supported by a wide number of upregulated matrix and lysosomal proteases in the lung after MWCNT exposure. The peptide fraction was then found bioactive, producing endothelial cell inflammation and vascular dysfunction ex vivo akin to that induced with whole serum. Results implicate receptor ligand functionality in driving systemic effects, exemplified by an identified 59-mer thrombospondin fragment, replete with CD36 modulatory motifs, that when synthesized produced an anti-angiogenic response in vitro matching that of the peptide fraction. Other identified peptides point to integrin ligand functionality and more broadly to a diversity of receptor-mediated bioactivity induced by the peptidomic response to nanoparticle exposure. The present study demonstrates that pulmonary-sequestered nanoparticles, such as multi-walled carbon nanotubes, acutely upregulate a diverse profile of matrix proteases, and induce a complex peptidomic response across lung and blood compartments. The serum peptide fraction, having cell-surface receptor ligand properties, conveys peripheral bioactivity in promoting endothelial cell inflammation, vasodilatory dysfunction and inhibiting angiogenesis. Results here establish peptide fragments as indirect, non-cytokine mediators and putative biomarkers of systemic health outcomes from nanoparticle exposure.

中文翻译：

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纳米颗粒暴露驱动循环生物活性肽组引起全身性炎症和血管功能障碍

导致全身性影响导致肺部纳米颗粒暴露的机制尚不清楚。最近的工作已经建立了一种间接过程，通过这种过程，从肺部释放到循环系统中的因子会促进全身性炎症和细胞功能异常，特别是在脉管系统上。但是，循环贡献因子的组成及其产生方式仍然未知。有证据表明基质蛋白酶参与。因此，在这里，我们使用了具有良好血管效应的，特征明确的多壁碳纳米管（MWCNT）口咽抽吸模型，来评估纳米颗粒诱导的肽片段在驱动系统病理生物学中的独特作用。与数据无关的质谱分析能够对富集肽段中的841个重要MWCNT响应进行无偏定量表征，其中567个因子证明了动物配对支气管肺泡灌洗液与血清生物流体之间的显着相关性。对已知基质蛋白酶底物和预测的信号转导基序进行数据库搜索，能够鉴定73 MWCNT反应肽，这些肽与异常的心血管表型，细胞外基质组织，免疫炎症过程，细胞受体信号转导和MWCNT改变显着相关血清外来体人群。MWCNT暴露后，肺中大量上调的基质和溶酶体蛋白酶支持多种肽反应的产生。然后发现该肽部分具有生物活性，与全血清诱导的炎症类似，在体外产生内皮细胞炎症和血管功能障碍。结果暗示受体配体功能在驱动全身作用中，以鉴定的59-mer血小板反应蛋白片段为例，该片段充满CD36调节基序，在合成时在体外产生与肽级分相匹配的抗血管生成反应。其他鉴定出的肽指向整联蛋白配体的功能，更广泛地指向由纳米粒子暴露的肽反应诱导的受体介导的生物活性的多样性。本研究表明，肺部隔离的纳米颗粒（例如多壁碳纳米管）会急剧上调基质蛋白酶的多种分布，并诱导跨肺和血液隔室的复杂的肽反应。血清肽部分，具有细胞表面受体配体性质的细胞，在促进内皮细胞发炎，血管舒张功能障碍和抑制血管生成方面传递着周围的生物活性。此处的结果将肽片段确定为纳米颗粒暴露导致的系统健康结果的间接，非细胞因子介质和假定的生物标志物。