Department of Anesthesiology and Surgical Intensive Care Unit, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, No.1665, Kongjiang Road, Yangpu District, Shanghai 200092, China.
Mol Pharm. 2022 Nov 7;19(11):4254-4263. doi: 10.1021/acs.molpharmaceut.2c00542. Epub 2022 Sep 29.
Sepsis is a global disease burden, and approximately 40% of cases develop acute lung injury (ALI). Bone marrow mesenchymal stromal cells (BMSCs) and their exosomes are widely used in treating a variety of diseases including sepsis. As an acute phase protein, serum amyloid A1 (SAA1) regulates inflammation and immunity. However, the role of SAA1 in BMSCs-exosomes in septic lung injury remains to be elucidated. Exosomes derived from serum and BMSCs were isolated by ultracentrifugation. SAA1 was silenced or overexpressed in mouse BMSCs using lentiviral plasmids, containing either SAA1-targeting short interfering RNAs or SAA1 cDNA. Sepsis was induced by cecal ligation and puncture (CLP). LPS was used to induce ALI in mice. Mouse alveolar macrophages were isolated by flow cytometry. Levels of SAA1, endotoxin, TNF-α, and IL-6 were measured using commercial kits. LPS internalization was monitored by immunostaining. RT-qPCR or immunoblots were performed to test gene and protein expressions. Serum exosomes of patients with sepsis-induced lung injury had significantly higher levels of SAA1, endotoxin, TNF-α, and IL-6. Overexpression of SAA1 in BMSCs inhibited CLP- or LPS-induced lung injury and decreased CLP- or LPS-induced endotoxin, TNF-α, and IL-6 levels. Administration of the SAA1 blocking peptide was found to partially inhibit SAA1-induced LPS internalization by mouse alveolar macrophages and reverse the protective effect of SAA1. In conclusion, BMSCs inhibit sepsis-induced lung injury through exosomal SAA1. These results highlight the importance of BMSCs, exosomes, and SAA1, which may provide novel directions for the treatment of septic lung injury.
脓毒症是一种全球性疾病负担，约有 40%的病例会发展为急性肺损伤（ALI）。骨髓间充质干细胞（BMSCs）及其外泌体被广泛用于治疗包括脓毒症在内的多种疾病。血清淀粉样蛋白 A1（SAA1）作为一种急性期蛋白，调节炎症和免疫。然而，SAA1 在 BMSCs 外泌体治疗脓毒症肺损伤中的作用仍有待阐明。通过超速离心从血清和 BMSCs 中分离出外泌体。使用含有 SAA1 靶向短发夹 RNA 或 SAA1 cDNA 的慢病毒质粒在小鼠 BMSCs 中沉默或过表达 SAA1。通过盲肠结扎和穿孔（CLP）诱导脓毒症。用 LPS 诱导小鼠 ALI。通过流式细胞术分离小鼠肺泡巨噬细胞。使用商业试剂盒测量 SAA1、内毒素、TNF-α 和 IL-6 的水平。通过免疫染色监测 LPS 内化。进行 RT-qPCR 或免疫印迹以测试基因和蛋白表达。脓毒症诱导肺损伤患者的血清外泌体中 SAA1、内毒素、TNF-α 和 IL-6 的水平明显升高。BMSCs 中 SAA1 的过表达抑制 CLP 或 LPS 诱导的肺损伤，并降低 CLP 或 LPS 诱导的内毒素、TNF-α 和 IL-6 水平。发现 SAA1 阻断肽的给药可部分抑制 SAA1 诱导的 LPS 内化，并逆转 SAA1 的保护作用。总之，BMSCs 通过外泌体 SAA1 抑制脓毒症诱导的肺损伤。这些结果强调了 BMSCs、外泌体和 SAA1 的重要性，这可能为脓毒症肺损伤的治疗提供新的方向。
