Rodovalho Vinícius de Rezende, da Luz Brenda Silva Rosa, Rabah Houem, do Carmo Fillipe Luiz Rosa, Folador Edson Luiz, Nicolas Aurélie, Jardin Julien, Briard-Bion Valérie, Blottière Hervé, Lapaque Nicolas, Jan Gwenaël, Le Loir Yves, de Carvalho Azevedo Vasco Ariston, Guédon Eric
INRAE, Institut Agro, STLO, Rennes, France.
Laboratory of Cellular and Molecular Genetics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil.
Front Microbiol. 2020 Jul 7;11:1544. doi: 10.3389/fmicb.2020.01544. eCollection 2020.
Extracellular vesicles (EVs) are nanometric spherical structures involved in intercellular communication, whose production is considered to be a widespread phenomenon in living organisms. Bacterial EVs are associated with several processes that include survival, competition, pathogenesis, and immunomodulation. Among probiotic Gram-positive bacteria, some strains exhibit anti-inflammatory activity, notably via surface proteins such as the surface-layer protein B (SlpB). We have hypothesized that, in addition to surface exposure and secretion of proteins, may produce EVs and thus export immunomodulatory proteins to interact with the host. In order to demonstrate their production in this species, EVs were purified from cell-free culture supernatants of the probiotic strain CIRM-BIA 129, and their physicochemical characterization, using transmission electron microscopy and nanoparticle tracking analysis (NTA), revealed shapes and sizes typical of EVs. Proteomic characterization showed that EVs contain a broad range of proteins, including immunomodulatory proteins such as SlpB. protein-protein interaction predictions indicated that EV proteins could interact with host proteins, including the immunomodulatory transcription factor NF-κB. This potential interaction has a functional significance because EVs modulate inflammatory responses, as shown by IL-8 release and NF-κB activity, in HT-29 human intestinal epithelial cells. Indeed, EVs displayed an anti-inflammatory effect by modulating the NF-κB pathway; this was dependent on their concentration and on the proinflammatory inducer (LPS-specific). Moreover, while this anti-inflammatory effect partly depended on SlpB, it was not abolished by EV surface proteolysis, suggesting possible intracellular sites of action for EVs. This is the first report on identification of derived EVs, alongside their physicochemical, biochemical and functional characterization. This study has enhanced our understanding of the mechanisms associated with the probiotic activity of and identified opportunities to employ bacterial-derived EVs for the development of bioactive products with therapeutic effects.
细胞外囊泡（EVs）是参与细胞间通讯的纳米级球形结构，其产生被认为是生物体中一种广泛存在的现象。细菌EVs与包括生存、竞争、发病机制和免疫调节在内的多种过程相关。在益生菌革兰氏阳性菌中，一些菌株表现出抗炎活性，特别是通过诸如表层蛋白B（SlpB）等表面蛋白。我们推测，除了蛋白质的表面暴露和分泌外， 可能会产生EVs，从而输出免疫调节蛋白以与宿主相互作用。为了证明该物种中EVs的产生，从益生菌菌株CIRM-BIA 129的无细胞培养上清液中纯化了EVs，并且使用透射电子显微镜和纳米颗粒跟踪分析（NTA）对其进行的物理化学表征揭示了EVs典型的形状和大小。蛋白质组学表征表明，EVs包含多种蛋白质，包括诸如SlpB等免疫调节蛋白。 蛋白质-蛋白质相互作用预测表明，EV蛋白可以与宿主蛋白相互作用，包括免疫调节转录因子NF-κB。这种潜在的相互作用具有功能意义，因为EVs可调节炎症反应，如在HT-29人肠上皮细胞中通过IL-8释放和NF-κB活性所显示的那样。实际上，EVs通过调节NF-κB途径表现出抗炎作用；这取决于它们的浓度和促炎诱导剂（LPS特异性）。此外，虽然这种抗炎作用部分取决于SlpB，但它不会因EV表面蛋白水解而消除，这表明EVs可能存在细胞内作用位点。这是关于鉴定 衍生的EVs及其物理化学、生物化学和功能表征的第一份报告。这项研究增进了我们对与 益生菌活性相关机制的理解，并确定了利用细菌衍生的EVs开发具有治疗作用的生物活性产品的机会。 （注：原文中部分内容缺失，已按完整翻译要求尽量完整呈现）
