Wang Yan, Zhang Dong, Liu Tian, Wang Jun-Fei, Wu Jin-Xiang, Zhao Ji-Ping, Xu Jia-Wei, Zhang Jin-Tao, Dong Liang
Department of Pulmonary Diseases, Qilu Hospital (Qingdao), Cheeloo College of Medicine, Shandong University, Qingdao, Shandong, People's Republic of China.
Department of Respiratory, Shandong Qianfoshan Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.
Inflamm Res. 2021 Jul;70(7):777-787. doi: 10.1007/s00011-021-01475-w. Epub 2021 Jun 2.
Asthma, a well-known disease with high morbidity, is characterized by chronic airway inflammation. However, the allergic inflammation mechanisms of follistatin-like protein 1 (FSTL1) have not been elucidated. This study aims to investigate the effects of FSTL1 in ovalbumin (OVA)-induced mice and macrophages on nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3)/interleukin-1β (IL-1β) signaling pathway.
Mice were randomly divided into control-WT, OVA-WT, control-Fstl1, OVA-Fstl1. Histological changes were assessed by HE and PAS staining. The protein levels of Muc-5AC, FSTL1, NLRP3, and IL-1β in lung tissue were detected by immunohistochemistry and ELISA. The bronchoalveolar lavage fluid (BALF) in mice and human serum samples were detected by ELISA. Then, mice were grouped into control, FSTL1, MCC950 + FSTL1 to further investigate the relationship between FSTL1 and NLRP3/IL-1β. Alveolar macrophage cells (MH-S cells) were separated into control, OVA, FSTL1, OVA + FSTL1, OVA + siNC, OVA + siFSTL1, MCC950, and FSTL1 + MCC950 groups to explore the effect of FSTL1 on the NLRP3/IL-1β signaling. The protein expression of NLRP3 and IL-1β in MH-S cells was detected by Western blot analysis.
The present results uncovered that Fstl1 significantly ameliorated OVA-induced Muc-5AC production and mucus hypersecretion. Fstl1 was also found to decrease the production of inflammatory cytokines and inflammatory cell infiltration in OVA-induced asthmatic mice. Meanwhile, the serum concentrations of FSTL1 and IL-1β were higher in asthma subjects than the health subjects, and Fstl1 ameliorated the production of NLRP3 and IL-1β in OVA-induced asthmatic mice. Furthermore, mice by injected FSTL1 substantially stimulated the expression of NLRP3 and IL-1β, while pretreatment with MCC950 in mice significantly weakened the production of NLRP3 and IL-1β induced by injection FSTL1. Pretreatment with siFSTL1 or MCC950 significantly reduced the production of NLRP3 and IL-1β induced by OVA or FSTL1 in MH-S cells.
The study results showed that FSTL1 played an important role in allergic airway inflammation by activating NLRP3/IL-1β. Hence, inhibition FSTL1 could be applied as a therapeutic agent against asthma.
哮喘是一种发病率高的常见疾病，其特征为慢性气道炎症。然而，卵泡抑素样蛋白1（FSTL1）的过敏性炎症机制尚未阐明。本研究旨在探讨FSTL1在卵清蛋白（OVA）诱导的小鼠和巨噬细胞中对核苷酸结合寡聚化结构域样受体含亮氨酸重复序列蛋白3（NLRP3）/白细胞介素-1β（IL-1β）信号通路的影响。
将小鼠随机分为对照-WT、OVA-WT、对照-Fstl1、OVA-Fstl1组。通过苏木精-伊红（HE）和过碘酸-雪夫（PAS）染色评估组织学变化。采用免疫组织化学和酶联免疫吸附测定（ELISA）检测肺组织中黏蛋白5AC（Muc-5AC）、FSTL1、NLRP3和IL-1β的蛋白水平。通过ELISA检测小鼠支气管肺泡灌洗液（BALF）和人血清样本。然后，将小鼠分为对照、FSTL1、MCC950 + FSTL1组，以进一步研究FSTL1与NLRP3/IL-1β之间的关系。将肺泡巨噬细胞（MH-S细胞）分为对照、OVA、FSTL1、OVA + FSTL1、OVA + 阴性对照小干扰RNA（siNC）、OVA + 小干扰RNA FSTL1（siFSTL1）、MCC950和FSTL1 + MCC950组，以探讨FSTL1对NLRP3/IL-1β信号传导的影响。通过蛋白质免疫印迹分析检测MH-S细胞中NLRP3和IL-1β的蛋白表达。
目前的结果表明，Fstl1显著改善了OVA诱导的Muc-5AC产生和黏液分泌过多。还发现Fstl1可减少OVA诱导的哮喘小鼠中炎性细胞因子的产生和炎性细胞浸润。同时，哮喘患者血清中FSTL1和IL-1β的浓度高于健康受试者，且Fstl1改善了OVA诱导的哮喘小鼠中NLRP3和IL-1β的产生。此外，注射FSTL1的小鼠显著刺激了NLRP3和IL-1β的表达，而小鼠预先用MCC950处理则显著减弱了注射FSTL1诱导的NLRP3和IL-1β的产生。用siFSTL1或MCC950预处理可显著降低OVA或FSTL1在MH-S细胞中诱导的NLRP3和IL-1β的产生。
研究结果表明，FSTL1通过激活NLRP3/IL-1β在过敏性气道炎症中起重要作用。因此，抑制FSTL1可作为一种抗哮喘治疗药物。
