Acetaminophen (APAP) overdose is the common cause of acute liver failure (ALF) due to the oxidative damage of multiple cellular components. This study aimed to investigate whether plasma membrane vesicles (PMVs) from human umbilical cord mesenchymal stem cells (hUCMSCs) could be exploited as a novel stem cell therapy for APAP-induced liver injury. PMVs from hUCMSCs were prepared with an improved procedure including a chemical enucleation step followed by a mechanical extrusion. PMVs of hUCMSCs were characterized and supplemented to hepatocyte cultures. Rescue of APAP-induced hepatocyte damage was evaluated. The hUCMSCs displayed typical fibroblastic morphology and multipotency when cultivated under adipogenic, osteogenic, or chondrogenic conditions. PMVs of hUCMSCs maintained the stem cell phenotype, including the presence of CD13, CD29, CD44, CD73, and HLA-ABC, but the absence of CD45, CD117, CD31, CD34, and HLA-DR on the plasma membrane surface. RT-PCR and transcriptomic analyses showed that PMVs were similar to hUCMSCs in terms of mRNA profile, including the expression of stemness genes GATA4/5/6, Nanog, and Oct1/2/4. GO term analysis showed that the most prominent reduced transcripts in PMVs belong to integral membrane components, extracellular vesicular exosome, and extracellular matrix. Immunofluorescence labeling/staining and confocal microscopy assays showed that PMVs enclosed cellular organelles, including mitochondria, lysosomes, proteasomes, and endoplasmic reticula. Incorporation of the fusogenic VSV-G viral membrane glycoprotein stimulated the endosomal release of PMV contents into the cytoplasm. Further, the addition of PMVs and a mitochondrial-targeted antioxidant Mito-Tempo into cultures of APAP-treated HepG2 cells resulted in reduced cell death, enhanced viability, and increased mitochondrial membrane potential. Lastly, this study demonstrated that the redox state and activities of aminotransferases were restored in APAP-treated HepG2 cells. The results suggest that PMVs from hUCMSCs could be used as a novel stem cell therapy for the treatment of APAP-induced liver injury.

中文翻译：

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人脐带间充质干细胞的质膜囊泡可改善对乙酰氨基酚诱导的HepG2细胞损伤：一种新型干细胞疗法。

由于多种细胞成分的氧化损伤，对乙酰氨基酚（APAP）过量是急性肝衰竭（ALF）的常见原因。这项研究旨在调查是否可以将人脐带间充质干细胞（hUCMSCs）的质膜囊泡（PMV）用作APAP诱导的肝损伤的新型干细胞疗法。来自hUCMSC的PMV的制备方法经过改进，包括化学去核步骤，然后进行机械挤出。hUCMSCs的PMVs被表征并补充到肝细胞培养物中。评价了APAP诱导的肝细胞损伤的挽救。在成脂，成骨或成软骨条件下培养时，hUCMSCs具有典型的成纤维细胞形态和多能性。hUCMSC的PMV保持干细胞表型，包括CD13，CD29，CD44，CD73和HLA-ABC，但质膜表面不存在CD45，CD117，CD31，CD34和HLA-DR。RT-PCR和转录组分析表明，PMV与hUCMSC相似，包括mRNA谱，包括干基因GATA4 / 5/6，Nanog和Oct1 / 2/4的表达。GO术语分析表明，PMV中最显着的转录本还原是完整的膜成分，细胞外囊泡外泌体和细胞外基质。免疫荧光标记/染色和共聚焦显微镜分析表明，PMV封闭了细胞器，包括线粒体，溶酶体，蛋白酶体和内质网。融合型VSV-G病毒膜糖蛋白的掺入刺激了PMV内含物释放到细胞质中。进一步，在APAP处理的HepG2细胞培养物中加入PMV和针对线粒体的抗氧化剂Mito-Tempo，可减少细胞死亡，提高生存力并增加线粒体膜电位。最后，这项研究表明，APAP处理的HepG2细胞中氧化还原状态和氨基转移酶的活性得以恢复。结果表明，来自hUCMSCs的PMV可用作治疗APAP所致肝损伤的新型干细胞疗法。