People with the genetic disease cystic fibrosis (CF) often have chronic airway infections and produce airway secretions called sputum. A better understanding of sputum composition is desired in order to track changes in response to CF therapeutics and to improve laboratory models for the study of CF airway infections. The glycosylated protein mucin is a primary component. Along with extracellular DNA, mucin gives rise to the high viscoelasticity of sputum, which inhibits airway clearance and is thought to promote chronic airway infections in people with CF. Past studies of sputum composition identified additional biomolecular components of sputum including other proteins, both glycosylated and not glycosylated, free amino acids, and lipids. Typically, studies of sputum, as well as other complex biological materials, have focused on soluble or isolated components. Solid-state NMR is not limited to the study of soluble components. Instead, it can provide molecular-level information about insoluble biological samples. Additionally, solid-state NMR can provide information about sample composition without requiring any processing of the sample, eliminating the possibility of misestimating certain components due to insolubility or potential sample loss in isolation steps. In this study, we used both 13C and 31P CPMAS to investigate the total composition of sputum samples obtained from six people with CF. We compared these spectra to those of commercially available mucin, DNA, and phospholipid samples. Lastly, we performed complementary biochemical analyses to identify specific proteins present in the sputum samples. Overall, our findings provide insight into the composition of unprocessed sputum samples from people with CF, which can be used as a benchmark for future investigations of CF and infections in the airways of people with CF. Further, this study provides opportunities to expand the solid-state NMR approach to include dynamic nuclear polarization (DNP) to obtain high-resolution information of sputum and similar biological samples that are not feasible to isotopically enrich.

中文翻译：

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囊性纤维化患者痰液的固体 NMR 成分分析


患有遗传病囊性纤维化 （CF） 的人通常患有慢性气道感染，并产生称为痰液的气道分泌物。为了跟踪对 CF 治疗的反应变化并改进用于研究 CF 气道感染的实验室模型，需要更好地了解痰液成分。糖基化蛋白粘蛋白是主要成分。粘蛋白与细胞外 DNA 一起产生痰液的高粘弹性，从而抑制气道清除，并被认为会促进 CF 患者的慢性气道感染。过去对痰液成分的研究确定了痰液的其他生物分子成分，包括其他蛋白质，包括糖基化和非糖基化、游离氨基酸和脂质。通常，对痰液以及其他复杂生物材料的研究主要集中在可溶性或分离的成分上。固体 NMR 不仅限于对可溶性成分的研究。相反，它可以提供有关不溶性生物样品的分子水平信息。此外，固体 NMR 无需对样品进行任何处理即可提供有关样品成分的信息，从而消除了由于分离步骤中的不溶性或潜在样品损失而误估某些成分的可能性。在这项研究中，我们使用 13C 和 31P CPMAS 来研究从 6 名 CF 患者获得的痰液样本的总组成。我们将这些光谱与市售粘蛋白、DNA 和磷脂样本的光谱进行了比较。最后，我们进行了互补生化分析以鉴定痰液样本中存在的特定蛋白质。 总体而言，我们的研究结果提供了对 CF 患者未处理痰液样本成分的见解，这可以用作未来研究 CF 和 CF 患者气道感染的基准。此外，这项研究提供了扩展固体 NMR 方法的机会，包括动态核极化 （DNP），以获得痰液和类似生物样品的高分辨率信息，这些信息无法同位素富集。