血清外泌体中长链RNA作为早期肾癌诊断标志物的研究

摘要 目的：肾癌早期无明显症状,且无血清诊断标志物,晚期缺乏有效治疗手段。外泌体的生物学功能及现有研究报道为早期肾癌的诊断提供了新的理论基础和新思路,本文旨在尝试在肾癌血清外泌体中寻找肾癌诊断标志物以有助于提高肾癌的诊断水平,减少肾癌死亡率。方法：取肾癌肿瘤组和对照组各10个样本,用试剂盒（PEG法）分离外泌体,提取RNA后建库测序,数据处理后以|log2(fold change) |>1和显著水平q_value<0.001为标准筛选得一组显著差异基因,设计引物探针后大样本qPCR验证,对数据进行统计并作t检验分析,通过LASSO回归建立诊断模型,ROC-AUC判断诊断价值。结果：RNA-seq并深度分析筛出PFN2 RAB4B PHEX DACH1 Linc01765五个基因,运用LASSO回归建立了早期肾癌诊断模型,计算ROC-AUC值是0.818。结论：在肾癌血清外泌体中筛到一组基因,通过LASSO回归建立早期肾癌诊断模型,ROC-AUC值达0.818,具有一定的临床应用价值。     

Regulated Capture by Exosomes of mRNAs for Cytoplasmic tRNA Synthetases

Although tRNA synthetases are enzymes that catalyze the first step of translation in the cytoplasm, surprising functions unrelated to translation have been reported. These studies, and the demonstration of novel activities of splice variants, suggest a far broader reach of tRNA synthetases into cell biology than previously recognized. Here we show that mRNAs for most tRNA synthetases can be detected in exosomes. Also detected in exosomes was an mRNA encoding a unique splice variant that others had associated with prostate cancer. The exosomal mRNAs encoding the native synthetase and its cancer-associated splice variant could be translated in vitro and in mammalian cells into stable proteins. Other results showed that selection by exosomes of the splice variant mRNA could be regulated by an external stimulus. Thus, a broad and diverse regulated pool of tRNA synthetase-derived mRNAs is packaged for genetic exchange.     

Secretory Mechanisms and Intercellular Transfer of MicroRNAs in Living Cells

The existence of circulating microRNAs (miRNAs) in the blood of cancer patients has raised the possibility that miRNAs may serve as a novel diagnostic marker. However, the secretory mechanism and biological function of extracellular miRNAs remain unclear. Here, we show that miRNAs are released through a ceramide-dependent secretory machinery and that the secretory miRNAs are transferable and functional in the recipient cells. Ceramide, whose biosynthesis is regulated by neutral sphingomyelinase 2 (nSMase2), triggers secretion of small membrane vesicles called exosomes. The decreased activity of nSMase2 with a chemical inhibitor, GW4869, and a specific small interfering RNA resulted in the reduced secretion of miRNAs. Complementarily, overexpression of nSMase2 increased extracellular amounts of miRNAs. We also revealed that the endosomal sorting complex required for transport system is unnecessary for the release of miRNAs. Furthermore, a tumor-suppressive miRNA secreted via this pathway was transported between cells and exerted gene silencing in the recipient cells, thereby leading to cell growth inhibition. Our findings shed a ray of light on the physiological relevance of secretory miRNAs.     

Stem cell-derived exosomes-an emerging tool for myocardial regeneration

Cardiovascular diseases(CVDs) continue to represent the number one cause of death and disability in industrialized countries. The most severe form of CVD is acute myocardial infarction(AMI), a devastating disease associated with high mortality and disability. In a substantial proportion of patients who survive AMI, loss of functional cardiomyocytes as a result of ischaemic injury leads to ventricular failure, resulting in significant alteration to quality of life and increased mortality. Therefore, many attempts have been made in recent years to identify new tools for the regeneration of functional cardiomyocytes. Regenerative therapy currently represents the ultimate goal for restoring the function of damaged myocardium by stimulating the regeneration of the infarcted tissue or by providing cellsthat can generate new myocardial tissue to replace the damaged tissue. Stem cells(SCs) have been proposed as a viable therapy option in these cases. However, despite the great enthusiasm at the beginning of the SC era, justified by promising initial results, this therapy has failed to demonstrate a significant benefit in large clinical trials. One interesting finding of SC studies is that exosomes released by mesenchymal SCs(MSCs) are able to enhance the viability of cardiomyocytes after ischaemia/reperfusion injury, suggesting that the beneficial effects of MSCs in the recovery of functional myocardium could be related to their capacity to secrete exosomes. Ten years ago, it was discovered that exosomes have the unique property of transferring miRNA between cells, acting as miRNA nanocarriers. Therefore, exosomebased therapy has recently been proposed as an emerging tool for cardiac regeneration as an alternative to SC therapy in the post-infarction period. This review aims to discuss the emerging role of exosomes in developing innovative therapies for cardiac regeneration as well as their potential role as candidate biomarkers or for developing new diagnostic tools.     

胞外体--免疫治疗中的"特洛伊木马"

胞外体是源于多种真核细胞的多泡体,通过后者与质膜融合释放到细胞外的一种膜性小囊泡,在多种生理过程中发挥作用。近年研究发现,由抗原提呈细胞分泌的胞外体富集MHCI/II类分子、协同刺激分子、热休克蛋白70和热休克蛋白90等多种生物活性分子于一身,像“特洛伊木马”一样,在体内外免疫调节中起关键作用。本文就胞外体的基本特征、生产纯化方法及其作为一种新型的亚细胞疫苗在抗肿瘤和抗病毒免疫中的应用前景予以综述。     

Immunomodulation: The next target of mesenchymal stem cell-derived exosomes in the context of ischemic stroke

Ischemic stroke (IS) is the most prevalent form of brain disease, characterized by high morbidity, disability, and mortality. However, there is still a lack of ideal prevention and treatment measures in clinical practice. Notably, the transplantation therapy of mesenchymal stem cells (MSCs) has been a hot research topic in stroke. Nevertheless, there are risks associated with this cell therapy, including tumor formation, coagulation dysfunction, and vascular occlusion. Also, a growing number of studies suggest that the therapeutic effect after transplantation of MSCs is mainly attributed to MSC-derived exosomes (MSC-Exos). And this cell-free mediated therapy appears to circumvent many risks and difficulties when compared to cell therapy, and it may be the most promising new strategy for treating stroke as stem cell replacement therapy. Studies suggest that suppressing inflammation via modulation of the immune response is an additional treatment option for IS. Intriguingly, MSC-Exos mediates the inflammatory immune response following IS by modulating the central nervous system, the peripheral immune system, and immunomodulatory molecules, thereby promoting neurofunctional recovery after stroke. Thus, this paper reviews the role, potential mechanisms, and therapeutic potential of MSC-Exos in post-IS inflammation in order to identify new research targets.