Pérez-Cabezas Begoña, Santarém Nuno, Cecílio Pedro, Silva Cátia, Silvestre Ricardo, A M Catita José, Cordeiro da Silva Anabela
Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.
Parasite Disease Group, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
J Extracell Vesicles. 2018 Nov 8;8(1):1541708. doi: 10.1080/20013078.2018.1541708. eCollection 2019.
The use of secretion pathways for effector molecule delivery by microorganisms is a trademark of pathogenesis. extracellular vesicles (EVs) were shown to have significant immunomodulatory potential. Still, they will act in conjunction with other released parasite-derived products that might modify the EVs effects. Notwithstanding, the immunomodulatory properties of these non-vesicular components and their influence in the infectious process remains unknown. To address this, we explored both in vitro and in vivo the immunomodulatory potential of promastigotes extracellular material (EXO), obtained as a whole or separated in two different fractions: EVs or vesicle depleted EXO (VDE). Using an air pouch model, we observed that EVs and VDE induced a dose-dependent cell recruitment profile different from the one obtained with parasites, attracting significantly fewer neutrophils and more dendritic cells (DCs). Additionally, when we co-inoculated parasites with extracellular products a drop in cell recruitment was observed. Moreover, in vitro, while VDE (but not EVs) downregulated the expression of DCs and macrophages activation markers, both products were able to diminish the responsiveness of these cells to LPS. Finally, the presence of extracellular products in the inoculum promoted a dose-dependent infection potentiation in vivo, highlighting their relevance for the infectious process. In conclusion, our data demonstrate that EVs are not the only relevant players among the parasite exogenous products. This, together with the dose-dependency observed, opens new avenues to the comprehension of infectious process. The approach presented here should be exploited to revisit existing data and considered for future studies in other infection models.
微生物利用分泌途径递送效应分子是其致病的一个标志。细胞外囊泡（EVs）已被证明具有显著的免疫调节潜力。然而，它们会与其他释放的寄生虫衍生产物协同作用，这些产物可能会改变EVs的效应。尽管如此，这些非囊泡成分的免疫调节特性及其在感染过程中的影响仍不清楚。为了解决这个问题，我们在体外和体内探索了前鞭毛体胞外物质（EXO）的免疫调节潜力，EXO作为一个整体获得，或分为两个不同的部分：EVs或无囊泡EXO（VDE）。使用气袋模型，我们观察到EVs和VDE诱导的剂量依赖性细胞募集谱与寄生虫诱导的不同，吸引的中性粒细胞明显较少，而树突状细胞（DCs）较多。此外，当我们将寄生虫与胞外产物共同接种时，观察到细胞募集减少。此外，在体外，虽然VDE（但不是EVs）下调了DCs和巨噬细胞激活标志物的表达，但两种产物都能够降低这些细胞对LPS的反应性。最后，接种物中胞外产物的存在促进了体内剂量依赖性的感染增强，突出了它们在感染过程中的相关性。总之，我们的数据表明，EVs不是寄生虫外源性产物中唯一相关的成分。这一点，连同观察到的剂量依赖性，为理解感染过程开辟了新的途径。这里提出的方法应该被用来重新审视现有数据，并考虑用于未来其他感染模型的研究。
