Ji Xiaoyi, Nie Chunhua, Yao Yuan, Ma Yu, Huang Huafei, Hao Chuangli
Department of Respiratory Medicine, Children's Hospital of Soochow University, Suzhou, China.
Jiaxing Maternal and Child Health Hospital, Jiaxing, China.
PeerJ. 2024 Apr 18;12:e17106. doi: 10.7717/peerj.17106. eCollection 2024.
Allergic asthma is the most prevalent asthma phenotype and is associated with the disorders of immune cells and glycolysis. Macrophages are the most common type of immune cells in the lungs. Calprotectin (S100A8 and S100A9) are two pro-inflammatory molecules that target the Toll-like receptor 4 (TLR4) and are substantially increased in the serum of patients with severe asthma. This study aimed to determine the effects of S100A8/A9 on macrophage polarization and glycolysis associated with allergic asthma.
To better understand the roles of S100A8 and S100A9 in the pathogenesis of allergic asthma, we used ovalbumin (OVA)-induced MH-S cells, and OVA-sensitized and challenged mouse models (wild-type male BALB/c mice). Enzyme-linked immunosorbent assay, quantitative real-time polymerase chain reaction, flow cytometry, hematoxylin-eosin staining, and western blotting were performed. The glycolysis inhibitor 3-bromopyruvate (3-BP) was used to observe changes in glycolysis in mice.
We found knockdown of S100A8 or S100A9 in OVA-induced MH-S cells inhibited inflammatory cytokines, macrophage polarization biomarker expression, and pyroptosis cell proportion, but increased anti-inflammatory cytokine interleukin (IL)-10 mRNA; also, glycolysis was inhibited, as evidenced by decreased lactate and key enzyme expression; especially, knockdown of S100A8 or S100A9 inhibited the activity of TLR4/myeloid differentiation primary response gene 88 (MyD88)/Nuclear factor kappa-B (NF-κB) signaling pathway. Intervention with lipopolysaccharides (LPS) abolished the beneficial effects of S100A8 and S100A9 knockdown. The observation of OVA-sensitized and challenged mice showed that S100A8 or S100A9 knockdown promoted respiratory function, improved lung injury, and inhibited inflammation; knockdown of S100A8 or S100A9 also suppressed macrophage polarization, glycolysis levels, and activation of the TLR4/MyD88/NF-κB signaling pathway in the lung. Conversely, S100A9 overexpression exacerbated lung injury and inflammation, promoting macrophage polarization and glycolysis, which were antagonized by the glycolysis inhibitor 3-BP.
S100A8 and S100A9 play critical roles in allergic asthma pathogenesis by promoting macrophage perturbation and glycolysis through the TLR4/MyD88/NF-κB signaling pathway. Inhibition of S100A8 and S100A9 may be a potential therapeutic strategy for allergic asthma.
过敏性哮喘是最常见的哮喘表型，与免疫细胞紊乱和糖酵解有关。巨噬细胞是肺中最常见的免疫细胞类型。钙卫蛋白（S100A8和S100A9）是两种靶向Toll样受体4（TLR4）的促炎分子，在重症哮喘患者血清中显著升高。本研究旨在确定S100A8/A9对与过敏性哮喘相关的巨噬细胞极化和糖酵解的影响。
为了更好地了解S100A8和S100A9在过敏性哮喘发病机制中的作用，我们使用了卵清蛋白（OVA）诱导的MH-S细胞，以及OVA致敏和激发的小鼠模型（野生型雄性BALB/c小鼠）。进行了酶联免疫吸附测定、定量实时聚合酶链反应、流式细胞术、苏木精-伊红染色和蛋白质印迹分析。使用糖酵解抑制剂3-溴丙酮酸（3-BP）观察小鼠糖酵解的变化。
我们发现，在OVA诱导的MH-S细胞中敲低S100A8或S100A9可抑制炎性细胞因子、巨噬细胞极化生物标志物表达和焦亡细胞比例，但增加抗炎细胞因子白细胞介素（IL）-10 mRNA；此外，糖酵解受到抑制，乳酸和关键酶表达降低证明了这一点；特别是，敲低S100A8或S100A9可抑制TLR4/髓样分化初级反应基因88（MyD88）/核因子κB（NF-κB）信号通路的活性。用脂多糖（LPS）干预消除了敲低S100A8和S100A9的有益作用。对OVA致敏和激发小鼠的观察表明，敲低S100A8或S100A9可促进呼吸功能，改善肺损伤，并抑制炎症；敲低S100A8或S100A9还可抑制肺中巨噬细胞极化、糖酵解水平以及TLR4/MyD88/NF-κB信号通路的激活。相反，S100A9过表达加剧了肺损伤和炎症，促进了巨噬细胞极化和糖酵解，而糖酵解抑制剂3-BP可拮抗这些作用。
S100A8和S100A9通过TLR4/MyD88/NF-κB信号通路促进巨噬细胞紊乱和糖酵解，在过敏性哮喘发病机制中起关键作用。抑制S100A8和S100A9可能是过敏性哮喘的一种潜在治疗策略。
