PDF(Pubmed)
Abstract：
Mounting evidence implicates extracellular vesicles (EVs) factors as mediators of cell therapy. Cardiosphere-derived cells are cardiac-derived cells with tissue reparative capacity. Activation of a downstream target of wnt/β-catenin signalling, tryptophan 2,3 dioxygenase (TDO2) renders therapeutically inert skin fibroblasts cardioprotective. Here, we investigate the mechanism by which concentrated conditioned media from TDO2-augmented fibroblasts (TDO2-CCM) exert cardioprotective effects. TDO2-CCM is cardioprotective in a mouse model of MI compared to CCM from regular fibroblasts (HDF-CCM). Transcriptomic analysis of cardiac tissue at 24 h demonstrates broad suppression of inflammatory and cell stress markers in animals given TDO2-CCM compared to HDF-CCM or vehicle. Sequencing analysis of TDO2-EV RNA demonstrated abundance of a small Y-derived small RNA dubbed \'NT4\'. Purification of TDO2-EVs by size-exclusion chromatography and RNAse protection assays demonstrated that NT4 is encapsulated inside EVs. Consistently with TDO2-CCM, macrophages exposed to NT4 showed suppression of the inflammatory and cell stress mediators, particularly p21/cdkn1a. NT4-depleted TDO2-CCM resulted in diminished immunomodulatory capacity. Finally, administration of NT4 alone was cardioprotective in an acute model of myocardial infarction. Taken together, these findings elucidate the mechanism by which TDO2 augmentation mediates potency in secreted EVs through enrichment of NT4 which suppresses upstream cell stress mediators including p21/cdkn1a.
摘要：
越来越多的证据表明细胞外囊泡（EV）因子是细胞治疗的介质。心球来源的细胞是具有组织修复能力的心脏来源的细胞。wnt/β-连环蛋白信号的下游靶标的激活，色氨酸2,3双加氧酶（TDO2）使治疗惰性皮肤成纤维细胞具有心脏保护作用。这里,我们研究了来自TDO2增强成纤维细胞的浓缩条件培养基（TDO2-CCM）发挥心脏保护作用的机制。与来自常规成纤维细胞的CCM(HDF-CCM)相比,TDO2-CCM在MI的小鼠模型中具有心脏保护性。在24小时时心脏组织的转录组学分析证明,与HDF-CCM或载体相比,在给予TDO2-CCM的动物中广泛抑制炎症和细胞应激标志物。TDO2-EVRNA的测序分析表明，有大量的Y衍生的小RNA，称为“NT4”。通过尺寸排阻色谱和RNA酶保护测定纯化TDO2-EV表明NT4被封装在EV内部。与TDO2-CCM一致,暴露于NT4的巨噬细胞显示抑制炎症和细胞应激介质，特别是p21/cdkn1a。NT4耗尽的TDO2-CCM导致免疫调节能力降低。最后,在急性心肌梗死模型中,单独给予NT4具有心肌保护作用.一起来看,这些发现阐明了TDO2增强通过富集NT4介导分泌型EV效力的机制,NT4抑制了包括p21/cdkn1a在内的上游细胞应激介质.
