Characterization of the Giardia intestinalis secretome during interaction with human intestinal epithelial cells: The impact on host cells
Characterization of the Giardia intestinalis secretome during interaction with human intestinal epithelial cells: The impact on host cells
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DOI：
10.1371/journal.pntd.0006120
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发表时间：
2017-12-01
影响因子：
3.8
通讯作者：
Svard, Staffan G.
中科院分区：
文献类型：
--
作者：
Ma'ayeh, Showgy Y.;Liu, Jingyi;Svard, Staffan G.
背景肠贾第虫是一种非侵入性原生动物寄生虫，可引起人类贾第虫病，这是寄生虫引起的最常见的腹泻形式。疾病机制尚未完全确定，已知的毒力因素很少。方法：为了确定可能的毒力因子并阐明导致疾病的机制途径，我们使用蛋白质组学方法鉴定了贾第鞭毛虫幼虫（WB和GS分离物分别为组合A和B）在体外与肠上皮细胞（IECs）相互作用时的主要排泄-分泌产物（ESPs）。发现IEC和寄生虫分泌组的主要部分是组成释放的蛋白质，其中大多数与代谢有关，但也有一些蛋白质在它们的相互作用下释放（WB和GS蛋白分别为87和41个，人类蛋白分别为76和45个）。在被寄生的IECs中，分泌组谱显示对细胞肌动蛋白骨架和诱导免疫反应的影响，而贾第鞭毛虫显示抗氧化、蛋白水解（蛋白酶相关）和诱导免疫反应。贾第鞭毛虫分泌组还含有免疫优势蛋白和糖基化蛋白，以及新的候选毒力因子和组合特异性差异。一小部分贾第鞭毛虫ESPs含有信号肽（两种分离株均为29%），并且在ESPs中检测到细胞外囊泡，提示有其他分泌途径。显微镜分析显示ESPs与IECs结合并部分内化。寄生虫ESPs降低ERK1/2和P38磷酸化和NF-kappa B核易位。贾第鞭毛虫ESPs改变了IECs中的基因表达，其转录谱表明免疫细胞通过趋化因子募集、葡萄糖稳态紊乱、胆固醇和脂质代谢、细胞周期和诱导凋亡。结论本研究首次确定了贾第鞭毛虫ESPs并评估了其对IECs的影响。它强调了宿主和寄生虫ESPs在相互作用中的重要性，并揭示了复杂的细胞反应，可以解释贾第虫病期间的疾病机制和减轻的炎症反应。
BackgroundGiardia intestinalis is a non-invasive protozoan parasite that causes giardiasis in humans, the most common form of parasite-induced diarrhea. Disease mechanisms are not completely defined and very few virulence factors are known.MethodologyTo identify putative virulence factors and elucidate mechanistic pathways leading to disease, we have used proteomics to identify the major excretory-secretory products (ESPs) when Giardia trophozoites of WB and GS isolates (assemblages A and B, respectively) interact with intestinal epithelial cells (IECs) in vitro.FindingsThe main parts of the IEC and parasite secretomes are constitutively released proteins, the majority of which are associated with metabolism but several proteins are released in response to their interaction (87 and 41 WB and GS proteins, respectively, 76 and 45 human proteins in response to the respective isolates). In parasitized IECs, the secretome profile indicated effects on the cell actin cytoskeleton and the induction of immune responses whereas that of Giardia showed anti-oxidation, proteolysis (protease-associated) and induction of encystation responses. The Giardia secretome also contained immunodominant and glycosylated proteins as well as new candidate virulence factors and assemblage-specific differences were identified. A minor part of Giardia ESPs had signal peptides (29% for both isolates) and extracellular vesicles were detected in the ESPs fractions, suggesting alternative secretory pathways. Microscopic analyses showed ESPs binding to IECs and partial internalization. Parasite ESPs reduced ERK1/2 and P38 phosphorylation and NF-kappa B nuclear translocation. Giardia ESPs altered gene expression in IECs, with a transcriptional profile indicating recruitment of immune cells via chemokines, disturbances in glucose homeostasis, cholesterol and lipid metabolism, cell cycle and induction of apoptosis.ConclusionsThis is the first study identifying Giardia ESPs and evaluating their effects on IECs. It highlights the importance of host and parasite ESPs during interactions and reveals the intricate cellular responses that can explain disease mechanisms and attenuated inflammatory responses during giardiasis.