1 GUNA - ATTRE (Advanced Therapies and Tissue Regeneration), Innovation Accelerator at CNR, Via Gobetti 101, 40129 Bologna, Italy.
2 National Institute of Biostructures and Biosystems (NIBB), Rome, Italy.
Cell Transplant. 2018 Jan;27(1):55-69. doi: 10.1177/0963689717723016.
Human mesenchymal stem cells (hMSCs) are an effective tool in regenerative medicine notably for their intrinsic plentiful paracrine activity rather than differentiating properties. The hMSC secretome includes a wide spectrum of regulatory and trophic factors, encompassing several naked molecules as well as different kinds of extracellular vesicles (EVs). Among EVs, exosomes represent an intriguing population, able to shuttle proteins, transcription factors, and genetic materials, with a relevant role in cell-to-cell communication, modulating biological responses in recipient cells. In this context, the extracellular milieu can greatly impact the paracrine activity of stem cells, modifying their metabolism, and the dynamics of vesicle secretion. In the present study, we investigated the effects elicited on exosome patterning by tailored, ad hoc formulated lipid supplementation (Refeed) in MSCs derived from human fetal membranes (hFM-MSCs). Wound healing experiments revealed that stem cell exposure to exosomes obtained from Refeed-supplemented hFM-MSCs increased their migratory capability, although the amount of exosomes released after Refeed supplementation was lower than that yielded from non-supplemented cells. We found that such a decrease was mainly due to a different rate of exosomal exocytosis rather than to an effect of the lipid supplement on the endocytic pathway. Endoplasmic reticulum homeostasis was modified by supplementation, through the upregulation of PKR-like ER kinase (PERK) and inositol-requiring enzyme 1α (IRE1α). Increased expression of these proteins did not lead to stress-induced, unfolded protein response (UPR)-mediated apoptosis, nor did it affect phosphorylation of p38 kinase, suggesting that PERK and IRE1α overexpression was due to augmented metabolic activities mediated by optimization of a cellular feeding network afforded through lipid supplementation. In summary, these results demonstrate how tailored lipid supplementation can successfully modify the paracrine features in hFM-MSCs, impacting both intracellular vesicle trafficking and secreted exosome number and function.
人骨髓间充质干细胞(hMSCs)是再生医学中有效的工具,尤其是因为其内在丰富的旁分泌活性,而不是分化特性。hMSC 分泌组包括广泛的调节和营养因子,包含多种裸露分子以及不同类型的细胞外囊泡(EVs)。在 EVs 中,外泌体代表了一个有趣的群体,能够转运蛋白质、转录因子和遗传物质,在细胞间通讯中具有重要作用,调节受体细胞中的生物学反应。在这种情况下,细胞外环境可以极大地影响干细胞的旁分泌活性,改变其代谢和囊泡分泌的动力学。在本研究中,我们研究了通过专门定制的、特定配方的脂质补充(再喂养)对源自人胎膜(hFM-MSCs)的 MSC 中外泌体模式的影响。伤口愈合实验表明,暴露于补充再喂养的 hFM-MSCs 来源的外泌体的干细胞增加了它们的迁移能力,尽管再喂养补充后的外泌体释放量低于未补充细胞的释放量。我们发现,这种减少主要是由于外泌体出胞的不同速率,而不是脂质补充对内吞途径的影响。通过上调 PKR 样内质网激酶(PERK)和肌醇需求酶 1α(IRE1α),内质网稳态得到了补充的调节。这些蛋白质的表达增加并没有导致应激诱导的未折叠蛋白反应(UPR)介导的细胞凋亡,也没有影响 p38 激酶的磷酸化,这表明 PERK 和 IRE1α 的过表达是由于通过脂质补充优化细胞喂养网络而介导的代谢活性增强。总之,这些结果表明,如何通过专门定制的脂质补充来成功地改变 hFM-MSCs 的旁分泌特征,从而影响细胞内囊泡运输以及分泌的外泌体数量和功能。