Acute lung injury (ALI)-triggered pulmonary injury has been associated with high mortality, despite advances in drug treatment and supportive therapy. Remarkable progress has been made in attenuating the inflammatory injury associated with ALI using mesenchymal stem cells (MSCs)-based cell and gene therapy. However, to date, the benefits of interleukin-35 (IL-35)-modified MSCs in ALI intervention have not been investigated. In the present study, adult male C57BL/6 mice randomly received intravenous infusion of adipose-derived mesenchymal stem cells (ADSCs) constitutively expressing IL-35 (IL-35-GFP-ADSCs) or GFP (GFP-ADSCs) via retrovirus-mediated transduction (8 × 105 cells per mice) or isotonic saline 7 days before ALI modeling to investigate the effect and related mechanism. ALI was performed by lipopolysaccharide (LPS) inhalation for 24 h. Normal mice served as the sham group. The results indicated that compared with GFP-ADSCs, IL-35-modified ADSCs significantly increased cellular and pulmonary IL-10 and IL-35 production. Pretreatment with IL-35-ADSCs markedly reduced body weight loss, pulmonary wet/dry weight ratio and pathological injury. The PO2 was rescued to normal levels in mice that received IL-35-ADSCs. IL-35-ADSCs infusion apparently inhibited IL-6 release, protein leakage and MPO activity but greatly elevated IL-35 level in the bronchoalveolar lavage fluid (BALF). Splenic regulatory T cells in IL-35-ADSCs-pretreated mice got effective increase. Moreover, IL-35-ADSCs pretreatment remarkably inhibited neutrophil and macrophage infiltration and greatly decreased IL-6, tumor necrosis factor α (TNF-α) and Toll-like receptor 4 (TLR4) expression. In conclusion, pretreatment with IL-35-engineered ADSCs provided effective protection against LPS-induced ALI through suppression of pulmonary inflammation and, thus, might be a promising strategy to improve outcomes after ALI. The enhanced paracrine and immunosuppressive capacity of IL-35-ADSCs might contribute to their beneficial effects. However, further studies are needed to illuminate the detailed mechanism.

中文翻译：

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用白介素 35 工程间充质干细胞预处理通过抑制肺部炎症来防止脂多糖诱导的急性肺损伤。

尽管药物治疗和支持疗法取得了进展，但急性肺损伤 (ALI) 引发的肺损伤与高死亡率相关。使用基于间充质干细胞 (MSCs) 的细胞和基因疗法在减轻与 ALI 相关的炎症损伤方面取得了显着进展。然而，迄今为止，尚未研究白介素 35 (IL-35) 修饰的 MSCs 在 ALI 干预中的益处。在本研究中，成年雄性 C57BL/6 小鼠随机接受静脉输注脂肪来源间充质干细胞 (ADSCs)，通过逆转录病毒介导的组成型表达 IL-35 (IL-35-GFP-ADSCs) 或 GFP (GFP-ADSCs)在 ALI 建模前 7 天转导（每只小鼠 8 × 105 个细胞）或等渗盐水以研究效果和相关机制。ALI 通过脂多糖 (LPS) 吸入进行 24 小时。正常小鼠作为假手术组。结果表明，与 GFP-ADSCs 相比，IL-35 修饰的 ADSCs 显着增加了细胞和肺 IL-10 和 IL-35 的产生。用 IL-35-ADSCs 预处理显着减少体重减轻、肺湿/干重比和病理损伤。在接受 IL-35-ADSCs 的小鼠中，PO2 被恢复到正常水平。IL-35-ADSCs 输注明显抑制了 IL-6 释放、蛋白质渗漏和 MPO 活性，但大大提高了支气管肺泡灌洗液 (BALF) 中的 IL-35 水平。IL-35-ADSCs 预处理小鼠的脾调节性 T 细胞得到有效增加。此外，IL-35-ADSCs预处理显着抑制中性粒细胞和巨噬细胞浸润，并大大降低IL-6、肿瘤坏死因子α（TNF-α）和Toll样受体4（TLR4）的表达。综上所述，用 IL-35 工程化的 ADSCs 预处理通过抑制肺部炎症提供了对 LPS 诱导的 ALI 的有效保护，因此，可能是改善 ALI 后结果的有希望的策略。IL-35-ADSCs 增强的旁分泌和免疫抑制能力可能有助于其有益作用。然而，需要进一步的研究来阐明详细的机制。