Objective

Regulatory T cells (Tregs) and T helper (Th) 17 cells are two subsets of CD4 + T cells with opposite effects which play a crucial role in the pathogenesis of lung injury. In this study, we aim to investigate the protective effect of Pseudomonas aeruginosa outer membrane vesicles (OMVs) preconditioning on lung ischemia–reperfusion (I/R) injury and potential mechanisms.

Methods

Pathogen-free C57BL/6 mice were randomly divided into four groups: control, Control + OMVs, I/R and I/R + OMVs groups. Bronchoalveolar lavage fluid (BALF), serum, and lung tissues were collected and analyzed for pathophysiology and immune mechanism.

Results

OMVs not only attenuated tissue injury and respiratory physiologic function but also mediated the downregulation of lung wet-to-dry weight ratio and the reduction of total protein concentration. The numbers of total cells, macrophages, neutrophils, and lymphocytes were markedly decreased in the I/R mice following OMVs preconditioning. OMVs also decreased inflammatory cytokines associated with CD4 + T cells in both BALF and serum. In addition, the level of Tregs and its transcription factor forkhead box P3 (Foxp3) were significantly increased, while the level of Th17 cells and its transcription factor retinoid-related orphan receptor γ (RORγt) were significantly decreased following OMVs preconditioning. In the process of exploring the underlying protection mechanisms of OMVs, we found that OMVs preconditioning significantly reduced protein expression of Toll-like receptor 4 (TLR4), which in turn not only inactivated myeloid differentiation factor 88 (MyD88) and Phosphorylated nuclear factor kappa B (p-NF-κB), but also simultaneously increased the levels of T-cell immunoglobulin and mucin domain-containing protein 3 (Tim-3).

Conclusions

These results suggest that OMVs preconditioning may ameliorate lung I/R injury by regulating the balance of Tregs and Th17 cells through Tim-3 and TLR4/NF-κB pathway.

中文翻译：

---

铜绿假单胞菌外膜囊泡通过 Tim-3 和 TLR4/NF-κB 通路调节调节性 T 细胞和 Th17 细胞的平衡来改善肺缺血再灌注损伤

客观的

调节性 T 细胞 (Tregs) 和 T 辅助 (Th) 17 细胞是 CD4 + T 细胞的两个亚群，具有相反的作用，在肺损伤的发病机制中起着至关重要的作用。在本研究中，我们旨在研究铜绿假单胞菌外膜囊泡 (OMV) 预处理对肺缺血再灌注 (I/R) 损伤的保护作用及其潜在机制。

方法

无病原体C57BL/6小鼠随机分为四组：对照组、对照组+OMVs组、I/R组和I/R+OMVs组。收集支气管肺泡灌洗液 (BALF)、血清和肺组织并分析其病理生理学和免疫机制。

结果

OMVs不仅减轻组织损伤和呼吸生理功能，而且介导肺干湿重比的下调和总蛋白浓度的降低。在 OMV 预处理后，I/R 小鼠的总细胞、巨噬细胞、中性粒细胞和淋巴细胞的数量显着减少。OMV 还降低了 BALF 和血清中与 CD4 + T 细胞相关的炎性细胞因子。此外，在 OMVs 预处理后，Tregs 及其转录因子叉头盒 P3（Foxp3）的水平显着增加，而 Th17 细胞及其转录因子维甲酸相关孤儿受体 γ（RORγt）的水平显着降低。在探索 OMV 底层保护机制的过程中，

结论

这些结果表明，OMVs 预处理可以通过 Tim-3 和 TLR4/NF-κB 通路调节 Tregs 和 Th17 细胞的平衡来改善肺 I/R 损伤。