PICK1 intervenes in immunosuppression and airway hyperresponsiveness in RSV-infected mouse by TGF-β/Nodal signaling pathway

Abstract

Objective To explore the mechanism by which PICK1 (protein interacting with Cα kinase 1) interferes with immunosuppression and airway hyperresponsiveness in RSV (respiratory syncytial virus)-infected mice with bronchial asthma (BA) via TGF- β (transformation growth factor-beta)/Nodal signaling pathway.

Methods Thirty mice were randomly divided into 3 groups ( n=10), which were control group, BA group, intervention group and FSC231 group. The BA model was established by RSV in the BA group and the FSC231 group, and the mice in FSC231 group was also intraperitoneally injected with the PICK1 inhibitor FSC231. Hematoxylin-eosin (HE) staining was used to observe the lung histopathological changes of the three groups of mice. The number of eosinophilia (EOS) in the alveolar lavage fluid was counted by measuring the airway resistance by a pulmonary function meter. Serum levels of interleukin (IL) - 17, IL-10 and immunoglobulin E (IgE) were measured by enzyme-linked immunosorbent assay. Flow cytometry was used to detect the levels of helper T cells 17 (Th17) and regulatory T cells (Tregs) in the blood.

Results The alveolar structure of the BA group was disordered, the bronchial stenosis, the wall thickening, and inflammatory infiltration. In the FSC231 group, the bronchial and alveolar structures were severely damaged, and the bronchial wall was congested, thickened, blocked in the bronchi, and severe inflammatory infiltration occurred. The EOS count in the BALF, serum IgE level, the airway resistance, the level of Nodal in lung tissue, the ratio of Th17 cells and serum IL-17 in the BA group were significantly higher than those of the control group ( P<0.05). Moreover, the EOS count in the BALF, serum IgE level, the airway resistance, the level of Nodal in lung tissue, the ratio of Th17 cells and serum IL-17 in the FSC231 group were significantly higher than those of the BA group ( P<0.05). Conversely, Treg cells and IL- 10 in the BA group were significantly lower than those of the control group ( P<0.05), and Treg cells and IL-10 in the FSC231 group were significantly lower than those of the BA group ( P<0.05).

Conclusion Inhibition of PICK1 may increase Th17 cells and decrease Treg cells by promoting TGF - β/Nodal signaling pathway, thereby aggravating immunosuppression and further improving airway hyperresponsiveness in BA mice.

Abstract

摘要： 目的 探究蛋白激酶 Cα 相互作用蛋白 1 (protein interacting with Cα kinase 1, PICK1) 通过 TGF-β/Nodal 信号 通路干预呼吸道合胞病毒 (respiratory syncytial virus, RSV) 感染小鼠支气管哮喘 (bronchial asthma, BA) 模型中免疫抑制 及气道高反应的机制研究。 方法 30 只小鼠随机分为 3 组 ( n=10) , 分 别为对照组、BA 组和 FSC231 组。 BA 组和 FSC231 组通过 RSV 建立 BA 模型, FSC231 组小鼠同时腹腔注射 PICK1 抑制剂 FSC231 干预。通过 HE 染色观察各组小 鼠肺组织病理学变化。通过肺功能仪检测气道阻力, 计数肺泡灌洗液中 EOS 数目。通过酶联免疫吸附法检测 IL-17、IL-10 和 IgE 水平。流式细胞术检测血液中 Th17 和 Tregs 水平。 结果 BA 组肺泡结构紊乱, 支气管狭窄, 管壁增厚, 出 现炎性浸润。FSC231 组支气管和肺泡结构严重损坏, 并且支气管壁充血、增厚, 支气管内阻塞, 出现严重的炎性浸润现 象。BA 组的 BALF 中 EOS 计数、血清 IgE 水平、气道阻力、肺组织 Nodal 水平、Th17 细胞比例和血清 IL-17 均高于对照组 ( P<0.05) , 而 FSC231 组的 BALF 中 EOS 计数、血清 IgE 水平、气道阻力、肺组织 Nodal 水平、Th17 细胞比例和血清 IL-17 则高于 BA 组 ( P<0.05) 。相反, BA 组的 Treg 细胞和 IL-10 低于对照组 ( P<0.05) , 而 FSC231 组的 Treg 细胞和 IL-10 则低 于 BA 组 ( P<0.05) 。 结论 抑制 PICK1 可能通过促进 TGF-β/Nodal 信号通路引起 Th17 细胞升高和 Treg 的降低, 从而加 重免疫抑制, 进一步提高 BA 小鼠气道高反应。