School of Medicine, Nankai University, Tianjin, People's Republic of China.
Tianjin First Central Hospital Clinic Institute, Tianjin Medical University, Tianjin, 300070, People's Republic of China.
J Nanobiotechnology. 2022 Apr 22;20(1):196. doi: 10.1186/s12951-022-01407-8.
Steatotic livers tolerate ischemia-reperfusion injury (IRI) poorly, increasing the risk of organ dysfunction. Ferroptosis is considered the initiating factor of organ IRI. Heme oxygenase oxygen-1 (HO-1)-modified bone marrow mesenchymal stem cells (BMMSCs) (HO-1/BMMSCs) can reduce hepatic IRI; however, the role of ferroptosis in IRI of steatotic grafts and the effect of HO-1/BMMSCs-derived exosomes (HM-exos) on ferroptosis remain unknown.
A model of rat liver transplantation (LT) with a severe steatotic donor liver and a model of hypoxia and reoxygenation (H/R) of steatotic hepatocytes were established. Exosomes were obtained by differential centrifugation, and the differentially expressed genes (DEGs) in liver after HM-exo treatment were detected using RNA sequencing. The expression of ferroptosis markers was analyzed. microRNA (miRNA) sequencing was used to analyze the miRNA profiles in HM-exos.
We verified the effect of a candidate miRNA on ferroptosis of H/R treated hepatocytes, and observed the effect of exosomes knockout of the candidate miRNA on hepatocytes ferroptosis. In vitro, HM-exo treatment reduced the IRI in steatotic grafts, and enrichment analysis of DEGs suggested that HM-exos were involved in the regulation of the ferroptosis pathway. In vitro, inhibition of ferroptosis by HM-exos reduced hepatocyte injury. HM-exos contained more abundant miR-124-3p, which reduced ferroptosis of H/R-treated cells by inhibiting prostate six transmembrane epithelial antigen 3 (STEAP3), while overexpression of Steap3 reversed the effect of mir-124-3p. In addition, HM-exos from cell knocked out for miR-124-3p showed a weakened inhibitory effect on ferroptosis. Similarly, HM-exo treatment increased the content of miR-124-3p in grafts, while decreasing the level of STEAP3 and reducing the degree of hepatic ferroptosis.
Ferroptosis is involved in the IRI during LT with a severe steatotic donor liver. miR-124-3p in HM-exos downregulates Steap3 expression to inhibit ferroptosis, thereby attenuating graft IRI, which might be a promising strategy to treat IRI in steatotic grafts.
脂肪肝肝脏对缺血再灌注损伤（IRI）的耐受性差，增加了器官功能障碍的风险。铁死亡被认为是器官 IRI 的起始因素。血红素加氧酶-1（HO-1）修饰的骨髓间充质干细胞（BMMSCs）（HO-1/BMMSCs）可减少肝 IRI；然而，铁死亡在脂肪肝供体肝移植（LT）中的作用以及 HO-1/BMMSCs 衍生的外泌体（HM-exos）对铁死亡的影响尚不清楚。
建立大鼠严重脂肪肝供肝 LT 模型和脂肪肝细胞缺氧复氧（H/R）模型。采用差速离心法获取外泌体，采用 RNA 测序检测 HM-exo 处理后肝组织中差异表达基因（DEGs）。分析铁死亡标志物的表达。采用 microRNA（miRNA）测序分析 HM-exos 中的 miRNA 谱。
验证了候选 miRNA 对 H/R 处理的肝细胞铁死亡的影响，并观察了外泌体敲除候选 miRNA 对肝细胞铁死亡的影响。体外，HM-exo 处理减轻了脂肪肝供体肝的 IRI，DEGs 富集分析提示 HM-exos 参与了铁死亡途径的调节。体外，HM-exos 通过抑制前列腺六跨膜上皮抗原 3（STEAP3）抑制铁死亡，减少 H/R 处理细胞的肝细胞损伤。HM-exos 含有更丰富的 miR-124-3p，通过抑制 STEAP3 减少 H/R 处理细胞的铁死亡，而过表达 Steap3 则逆转了 miR-124-3p 的作用。此外，miR-124-3p 敲除细胞的 HM-exos 显示出对铁死亡的抑制作用减弱。同样，HM-exo 处理增加了移植物中 miR-124-3p 的含量，降低了 STEAP3 的水平，减轻了肝铁死亡的程度。
铁死亡参与了严重脂肪肝供肝 LT 中的 IRI。HM-exos 中的 miR-124-3p 通过下调 Steap3 表达抑制铁死亡，从而减轻移植物 IRI，这可能是治疗脂肪肝移植物 IRI 的一种有前途的策略。
