肿瘤微环境中外泌体在肿瘤发生发展中作用及机制

外泌体(exosomes)是直径在30~100 nm,内含RNA、脂质和蛋白质的纳米级囊泡,来源于细胞内溶酶体微粒内陷形成的多囊泡体,与细胞膜融合后释放到胞外,是肿瘤微环境中细胞间通讯和遗传物质的重要载体。肿瘤在发生、发展过程中可通过外泌体与肿瘤微环境中的免疫细胞、内皮细胞和肿瘤相关成纤维细胞之间相互作用从而促进肿瘤的进展,其携带蛋白质、脂质和核酸等内容物释放到细胞外随着体液运输改变肿瘤微环境、促进肿瘤细胞增殖、加快血管形成及促进癌症发展;肿瘤微环境是由肿瘤细胞、巨噬细胞、成纤维细胞及细胞外基质等共同构成的局部稳态环境,在癌症的发生、复发、转移和化疗耐药等过程中发挥重要的作用。本综述着重讨论外泌体的生物学特性及对肿瘤微环境的影响,为研究及诊断治疗肿瘤提供新的思路。     

肿瘤外泌体在微环境细胞间通讯中的作用及其作为肿瘤标志物的研究进展

外泌体(exosome)是一种起源于内吞体系统的细胞外囊泡,是微环境中细胞间通讯的重要载体。肿瘤细胞在肿瘤进展过程中可以通过外泌体与微环境的免疫细胞、间质细胞和内皮细胞之间发生相互作用进而促进肿瘤进展。肿瘤外泌体中可以携带蛋白质、脂质和核酸等形式的生物信息分子,这些分子既可以对受体细胞进行驯化作用,同时有可能成为肿瘤特异性标志物,在肿瘤临床检验中发挥重要作用,因此,外泌体的研究已成肿瘤基础和临床检验研究中重要的新领域。该文就肿瘤外泌体在微环境中的多种细胞相互作用机制及其作为特异性肿瘤标志物的研究现状和前景作一概述。     

外泌体对肿瘤微环境的免疫调节作用及在肿瘤诊疗中的应用研究进展

外泌体属于一种纳米级的生物活动囊泡,其是由多种细胞分泌的,广泛分布在体液中,外泌体携带着来自于母体细胞的相关生物活性,可以在细胞间的信息交流中有效参与,并且可以对靶细胞的功能进行调节。外泌体作为肿瘤和免疫细胞的来源,在肿瘤微环境形成过程中作为调节因子积极的参与,使免疫应答有效增强,患者对免疫活化进行抑制,从而对肿瘤微环境进行调节,在肿瘤发生和进展等过程中存在一定的影响。     

外泌体的研究进展及其对神经系统疾病的免疫调节

外泌体是来源于细胞自身分泌的一种脂质双分子层包裹形成的膜性小体,参与调解机体免疫反应, 作为运输载体参与炎症反应,在肿瘤的发生发展和治疗过程中也起到一定作用。外泌体在多发性硬化、视 神经脊髓炎、重症肌无力等神经系统免疫疾病中发挥重要作用,同时也参与阿尔茨海默病、帕金森病等中枢 神经系统疾病的发生发展。本文就外泌体的性质、作用、获得、鉴别及其在中枢神经系统疾病中的研究进展 作一综述。     

间充质干细胞来源的外泌体在肿瘤治疗中的研究进展

间充质干细胞(MSC)是一种具有分化为不同细胞类型潜力的多能细胞。由于其免疫抑制和抗炎特性, 被广泛用于再生医学。MSC会产生大量可以影响肿瘤发展的外泌体。与MSC类似, MSC来源的外泌体(MSC-Exo)可以发挥抗肿瘤或促肿瘤作用。因此, MSC-Exo与肿瘤之间的关系仍然存在争议。外泌体作为天然囊泡, 可以作为优良的药物载体, 并显示出在靶向肿瘤治疗中的应用前景。本文对MSC-Exo的特征和潜力, 以及MSC-Exo在癌症治疗中的应用进行概述, 随后总结了MSC-Exo的给药方法和优点, 以及MSC-Exo作为药物载体的进展。     

外泌体在前列腺癌中的应用及其研究进展

前列腺癌起病隐匿,目前临床常用的生物学标志物——血清PSA易受年龄、炎症等因素影响造成误判,故仍需寻找更优的标志物,并建立更先进的诊治方案。外泌体是由各种细胞天然形成的纳米级胞外囊泡,携带有大量蛋白质、核酸和脂质等,其作为细胞间物质信息递送的载体在前列腺癌的发生、发展进程中发挥着重要作用,并在前列腺癌诊疗方面展现了巨大潜力。该文综述了外泌体的生物学特性、分离方法及其在前列腺癌发展与诊疗方面的研究进展。     

免疫细胞来源外泌体在肝脏疾病中作用研究进展

肝脏疾病是一组常见、病因复杂的消化系统疾病。外泌体是细胞释放的细胞外囊泡,通过其携带的蛋白质、核酸和脂质介导细胞间通信,调节受体细胞生物活性。免疫细胞来源外泌体在病毒性肝炎、肝纤维化、肝细胞癌等多种肝脏疾病的发生、发展中发挥重要作用,可能为肝脏疾病的治疗提供新途径,近年来已成为研究热点。本文就免疫细胞来源外泌体在肝脏疾病中作用的研究进展作一综述。     

外泌体分离和纯化方法研究进展

外泌体是由活细胞主动分泌的一种纳米级囊泡,内含蛋白质、核酸等生物活性物质,参与细胞间通讯,在肿瘤微环境调节、免疫识别、炎症反应等众多生理病理过程中发挥重要作用。作为一种运输载体,外泌体广泛存在于生物流体中,但由于其粒径小、内含物丰度低,能否获得高质量的外泌体成为后续研究成败的关键。虽然外泌体分离、纯化和鉴定方法日趋发展...     

不同细胞来源外泌体在骨科退行性疾病中的研究进展

外泌体是一种由细胞分泌至胞外的膜性囊泡样微体。外泌体在以骨关节炎（osteoarthritis，OA）和椎间盘退变为主的骨科退行性疾病的诊疗中具有应用价值。包括间充质干细胞（mesenchymal stem cell，MSC）在内的多种细胞来源的外泌体具有抑制软骨细胞退化、促进再生等作用。其中研究最为广泛的是MSC来源外泌体，其优点在于细胞来源丰富、产量较高、易获得。而软骨细胞外泌体内的微小RNA（microRNA，miRNA）表达谱与其亲本细胞存在显著差异，提示其在软骨分化和维持内稳态也具有重要作用。正常髓核细胞来源外泌体可促进MSC迁移及向髓核细胞定向分化，炎症下的滑膜细胞外泌体还可成为加重软骨退变的因素。本文通过对不同细胞来源外泌体在骨科退行性疾病中的研究进行综述，为该类疾病的诊断和治疗带来新的思路。     

外泌体的生物学特性及其微小RNA在脑梗死诊治中的应用

外泌体是由细胞主动分泌的胞外囊泡,内含多种细胞特异的蛋白质、脂质、核酸等。外泌体作为细胞间通讯的载体,参与了调节脑梗死后中枢神经系统修复及功能重塑的过程。随着研究深入,越来越多研究表明,外泌体来源的微小RNA(miRNA)在脑梗死诊断和治疗中扮演重要角色,现就外泌体的生物学特性及其miRNA的研究应用做一综述。     

Investigation of exosomes secreted by different normal and malignant cells in vitro and in vivo

Laser correlation spectroscopy, atomic force microscopy, and immunoaffinity chromatography were used to characterize exosomes produced by different human cells. The exosomes secreted into a culture medium by normal fibroblasts, dendritic cells, lymphocytes, as well as malignant cells obtained from tumors of various tissue origins. The similar investigations were made for exosomes detectable in plasma and cerebrospinal fluid. The dynamic light scattering technique has demonstrated that the exosomes from different sources are homogenous and similar in size of the order of 20 and 90 nm. The exceptional homogeneity of exosomes was confirmed by atomic force microscopy. The immunoaffinity method has shown that all the exosomes under study carry antigenic determinants recognizable by antibodies to the major histocompatibility complex of type 1 (HLA-ABC). A method is proposed for evidence-based detection of exosomes in various biological fluids. For this, dynamic light scattering detects 20- and 90-nm particles and whether they can be removed by immunoaffinity chromatography with HLA-ABC antibodies is checked.     

Use of exosomes as vectors to carry advanced therapies

Exosomes are microvesicles of nanometric size involved in the communication between cells and tissues. Inside their bilipidic membrane they carry nucleic acids such as cargos (DNA, miRNA, etc.). Some of the advantages that make exosomes very attractive therapeutic vehicles are (i) their tropism through different tissues, (ii) the ability to pass biological barriers and (iii) the protection of the encapsulated material from the immune system and degradation. Viruses are some of the most widely employed gene therapy vehicles; however, they are still facing many problems, such as inefficient tropism to damaged areas and their elimination by the immune system. One of the functions attributed to exosomes is the elimination of substances that could be harmful to the cell, including viruses. Recently it has been investigated whether complete viruses or part of them could be encapsulated in exosomes, for a new viral-exosome gene therapy approach. Moreover, nanotechnology is another type of advanced therapy (together with gene and cell therapies) that can be used, among other utilities, to transfer genetic material. Recently the field of encapsulation of nanomaterials in exosomes, with or without gene transfer, is increasing. In this review we will summarize all of those studies.

Exosomes as therapeutic carriers for advanced therapies.     

Exosomal-like vesicles with immune-modulatory features are present in human plasma and can induce CD4+ T-cell apoptosis in vitro

BACKGROUND: Exosomes are small membrane vesicles that are secreted from many cell types into various body fluids. These vesicles are thought to play a role in cell–cell interactions. STUDY DESIGN AND METHODS: Vesicles were isolated from human plasma of healthy donors by differential ultracentrifugation and ultrafiltration. The vesicles were identified by transmission electron microscopy, and their biochemical characteristics were analyzed by Western blot and flow cytometry. The immune‐modulatory ability of exosomal‐like vesicles was examined by incubating them with CD4+ T cells for CD4+ T‐cell proliferation and apoptosis assays in vitro. RESULTS: Vesicles purified from human plasma displayed shapes and sizes similar to those of previously described exosomes and contained exosomes marker proteins CD63 and CD81. They also expressed molecules such as MHC Class II molecules, CD80, CD86, and the cell signal transduction molecules Wnt3a, Wnt5a, and FasL. Furthermore, functional analysis showed that allogeneic plasma exosomes restrained the survival of CD4+ T cells. Plasma exosomes can induce dose‐dependent suppression of proliferation of activated CD4+ T cells, with the strongest responses induced by 500 µg/mL exosomes in vitro. Antibodies against exosomes FasL can block the activity of exosomes on CD4+ T‐cell apoptosis. Moreover, three different concentrations of CD4+ T cells were inhibited by plasma exosomes and the suppressive function was not dependent on interleukin‐2. CONCLUSION: Exosomes present in human plasma contain immunity‐associated molecules and can induce CD4+ T‐cell apoptosis in vitro. Plasma exosomes have the capacity to influence immune responses.     

Comparison of cell profiles of bronchial and bronchoalveolar lavage fluids between normal subjects and patients with idiopathic pulmonary fibrosis

The cell profiles of bronchial and bronchoalveolar lavage fluids (BLF and BALF) of patients with idiopathic pulmonary fibrosis (IPF) were compared with those of normal volunteers (NV) and age-matched control patients (CP), to characterize the cell profiles of the bronchoalveolar region in normals and patients with IPF. In BALF of nonsmokers from both control groups (NV and CP), alveolar macrophages (AM) were predominant and the percentage of neutrophil leukocytes and that of eosinophil leukocytes below 1% of the total cells. The percentage of neutrophils and that of bronchial epithelial cells were higher in BLF than in BALF of both control groups. Of the immune and inflammatory cells in BLF, the mean percentage of neutrophils was 12% in NV group and 42% in CP group. The percentage of neutrophils and that of eosinophils in BALF were higher in IPF group than in CP group, but the percentage of neutrophils in BLF of IPF group was comparable to that of CP group. In the IPF group, the percentage of neutrophils in BALF was lower than that in BLF. These results indicated that even in healthy subjects, a considerable number of neutrophils are present in the bronchial region and that the cell profile of the lavage fluid of the bronchoalveolar tree changes depending on the method of lavage. Presumably the higher percentage of neutrophils in BALF of patients with IPF is partly due to derangements of the alveolar structure, because the amount of saline infused into this region is limited.     

A Novel Nanoparticle Drug Delivery System: The Anti-inflammatory Activity of Curcumin Is Enhanced When Encapsulated in Exosomes

Monocyte-derived myeloid cells play vital roles in inflammation-related autoimmune/inflammatory diseases and cancers. Here, we report that exosomes can deliver anti-inflammatory agents, such as curcumin, to activated myeloid cells in vivo. This technology provides a means for anti-inflammatory drugs, such as curcumin, to target the inflammatory cells as well as to overcome unwanted off-target effects that limit their utility. Using exosomes as a delivery vehicle, we provide evidence that curcumin delivered by exosomes is more stable and more highly concentrated in the blood. We show that the target specificity is determined by exosomes, and the improvement of curcumin activity is achieved by directing curcumin to inflammatory cells associated with therapeutic, but not toxic, effects. Furthermore, we validate the therapeutic relevance of this technique in a lipopolysaccharide (LPS)-induced septic shock mouse model. We further show that exosomes, but not lipid alone, are required for the enhanced anti-inflammatory activity of curcumin. The specificity of using exosomes as a drug carrier creates opportunities for treatments of many inflammation-related diseases without significant side effects due to innocent bystander or off-target effects.     

Oxidant-mediated epithelial cell injury in idiopathic pulmonary fibrosis.

Lung inflammatory cells of patients with idiopathic pulmonary fibrosis (IPF) were evaluated for their ability to injure 51Cr-labeled AKD alveolar epithelial cells in the presence and absence of IPF alveolar epithelial lining fluid (ELF). The IPF cells were spontaneously releasing exaggerated amounts of superoxide (O.2) and hydrogen peroxide (H2O2) compared with normal (P less than 0.02). Cytotoxicity of the AKD cells was markedly increased when the IPF inflammatory cells were incubated with autologous ELF (P less than 0.02). The majority of IPF patients had ELF myeloperoxidase levels above normal (P less than 0.002). Incubation of IPF ELF with AKD cells in the presence of H2O2 caused increased cellular injury (P less than 0.01 compared with control), which was suppressed by methionine, a myeloperoxidase system scavenger. IPF patients with high concentrations of ELF myeloperoxidase deteriorated more rapidly than those with low ELF myeloperoxidase (P less than 0.05). Thus, IPF is characterized by an increased spontaneous production of oxidants by lung inflammatory cells, the presence of high concentrations of myeloperoxidase in the ELF of the lower respiratory tract, and a synergistic cytotoxic effect of alveolar inflammatory cells and ELF on lung epithelial cells, suggesting oxidants may play a role in causing the epithelial cell injury of this disorder.