Department of Pathology and Laboratory Medicine, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan.
Department of Respiratory Medicine and Rheumatology, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan; Research Center for Education of Health Bioscience, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan.
Allergol Int. 2022 Jul;71(3):395-404. doi: 10.1016/j.alit.2022.02.005. Epub 2022 Mar 25.
Refractory asthma, which is caused by several factors including neutrophil infiltration is a serious complication of bronchial asthma. We previously reported that nerve growth factor (NGF) is involved in AHR. NGF-derived induction of hyperalgesia is dependent on neutrophils; however, this relationship remains unclear in respiratory disease. In this study, we examined the roles of neutrophils and NGF in refractory asthma.
Using intranasal house dust mite sensitization, we established a mouse model of asthma with mixed inflammation (Mix-in). AHR, NGF production and hyperinnervation of the lungs were examined with or without different inhibitory treatments. The levels of the singlet oxygen markers, 10- and 12-(Z,E)-hydroxyoctadecadienoic acids (HODE) in the lungs, were measured by liquid chromatography-tandem mass spectrometry. An in vitro experiment was also performed to evaluate the direct effect of singlet oxygen on NGF production.
NGF production and hyperinnervation were higher in Mix-in mice than in conventional eosinophilic-asthmatic mice and were positively correlated with AHR. Asthmatic parameters were inhibited by NGF neutralizing Abs and myeloperoxidase (MPO) inhibition. The 10- and 12-(Z,E)-HODEs levels were increased in the lungs and were positively correlated with MPO activity and NGF production. NGF was produced by bronchial epithelial cells in vitro upon stimulation with singlet oxygen.
Our findings suggest that neutrophil MPO-derived singlet oxygen induces increased NGF production, leading to AHR and 10- and 12-(Z,E)-HODEs production. These findings may help to develop new therapies targeting this mechanism and to establish a new biomarker for non-type 2 and refractory asthma.
由多种因素引起的难治性哮喘，包括中性粒细胞浸润，是支气管哮喘的一种严重并发症。我们之前的研究表明，神经生长因子（NGF）参与了 AHR。NGF 诱导的痛觉过敏依赖于中性粒细胞，但这种关系在呼吸道疾病中尚不清楚。在这项研究中，我们研究了中性粒细胞和 NGF 在难治性哮喘中的作用。
我们通过鼻腔内尘螨致敏建立了一种混合炎症（Mix-in）的哮喘小鼠模型。使用或不使用不同的抑制性治疗方法，检查了 AHR、NGF 产生和肺的神经支配过度。通过液相色谱-串联质谱法测量了肺部的单线态氧标志物 10-和 12-（Z，E）-羟基十八碳二烯酸（HODE）的水平。还进行了一项体外实验来评估单线态氧对 NGF 产生的直接影响。
Mix-in 小鼠中的 NGF 产生和神经支配过度高于传统的嗜酸性哮喘小鼠，并且与 AHR 呈正相关。NGF 中和抗体和髓过氧化物酶（MPO）抑制抑制了哮喘参数。肺部的 10-和 12-（Z，E）-HODE 水平升高，与 MPO 活性和 NGF 产生呈正相关。在体外，支气管上皮细胞在单线态氧刺激下产生 NGF。
我们的研究结果表明，中性粒细胞 MPO 衍生的单线态氧诱导 NGF 产生增加，导致 AHR 和 10-和 12-（Z，E）-HODE 产生。这些发现可能有助于开发针对该机制的新疗法，并建立非 2 型和难治性哮喘的新生物标志物。
