发布: 2020年06月05日第10卷第11期 DOI: 10.21769/BioProtoc.3647 浏览次数: 3537
评审: Alexandros AlexandratosDhiman Sankar PalKathrin Sutter
相关实验方案
通过制备连续聚丙烯酰胺凝胶电泳和凝胶酶谱分析法纯化来自梭状龋齿螺旋体的天然Dentilisin复合物及其功能分析
Pachiyappan Kamarajan [...] Yvonne L. Kapila
2024年04月05日 1192 阅读
Abstract
The study of host/pathogen interactions at the cellular level during Plasmodium intra-erythrocytic cycle requires differential extraction techniques aiming to analyze the different compartments of the infected cell. Various protocols have been proposed in the literature to study specific compartments and/or membranes in the infected erythrocyte. The task remains delicate despite the use of enzymes or detergents theoretically capable of degrading specific membranes inside the infected cell.
The remit of this protocol is to propose a method to isolate the erythrocyte cytosol and ghosts from the other compartments of the infected cell via a percoll gradient. Also, the lysis of the erythrocyte membrane is done using equinatoxin II, which has proven to be more effective at erythrocyte lysis regardless of the cell infection status, compared to the commonly used streptolysin. The parasitophorous vacuole (PV) content is collected after saponin lysis, before recovering membrane and parasite cytosol proteins by Triton X-100 lysis. The lysates thus obtained are analyzed by Western blot to assess the accuracy of the various extraction steps. This protocol allows the separation of the host compartment from the parasite compartments (PV and parasite), leading to potential studies of host proteins as well as parasite proteins exported to the host cell.
Background
The protocol presented herein is an improvement of a protocol that we initially published in Scientific Reports. The initial goal of this protocol was to perform the characterization of a P. berghei protein exported by the parasite to its host cell. This allowed the confirmation of immunofluorescence assays showing the export of the protein–and its blockage by Brefeldin A–and the analysis of its interactome upon export in the infected erythrocyte (Gnangnon et al., 2019).
With the aim to provide an improved protocol herein, we refined the technique reported previously by including a percoll gradient step to separate the host cell materials from the parasite ones. After enriching the infected erythrocytes via a Nycodenz® layer, we use Equinatoxin II (EQT–Anderluh et al., 1996) to lyse infected erythrocytes, instead of Streptolysin (SLO) as proposed previously (Nyalwidhe and Lingelbach, 2006; Heiber and Spielmann, 2014; Külzer et al., 2015). We made this choice since a few studies have shown that EQT lyses all erythrocytes independently from their infection status, whereas SLO lyses preferentially uninfected erythrocytes (Jackson et al., 2007; Schön et al., 2008). A percoll gradient is then used to separate the erythrocyte components from the parasite ones. The preparation of this gradient is performed similarly to the one used for P. falciparum (Heiber and Spielmann, 2014).
The parasites embedded in their parasitophorous vacuole (PV) are further treated using saponin, which specifically lyses the PV membrane (Külzer et al., 2015). The final lysis step involves Triton X-100 to recover membrane and parasite cytosol proteins (Heiber and Spielmann, 2014).
Other intermediate lysis steps can also be set up to analyze the parasite compartments more in depth (Ghosh et al., 2017). The different lysates are analyzed by Western blot. The choice of the antibodies used to detect protein markers of each purified compartment was based on previous studies and on antisera availability from different laboratories (see Table 1) (Knapp et al., 1990; Kina et al., 2000; Blisnick et al., 2006; Hliscs et al., 2013; Külzer et al., 2015; Meibalan et al., 2015; Ghosh et al., 2017). The techniques used here are optimized to the study of P. berghei–infected erythrocytes (the antibodies listed in Table 1 cross-react with P. berghei antigens despite being initially raised against proteins from other Plasmodium species) and may require some modifications when studying other Plasmodium species. In the case of P. falciparum, the reader can refer to suggestions made by Külzer et al. (2015).
The protocol presented here will enable the analysis of the membrane and cytosol of erythrocytes infected by Plasmodium (and maybe other erythrocyte-infecting pathogens like Babesia, following protocol optimization). Further refinements could allow a more precise and specific analysis of all the different compartments of the infected cell at once, which will favor the study of host/pathogen interactions over the parasite intra-erythrocytic development (see the “Notes” section at the very end of this manuscript). This is of critical importance since this phase of the development cycle of the parasite is responsible for the symptoms of malaria.
Materials and Reagents
Note: All chemicals are stored in dedicated rooms and safety cabinets. They are manipulated in accordance with product safety data sheets (SDS) and manufacturer instructions were followed for shelf-life (see below for storage temperatures–RT = Room Temperature).
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文章信息
版权信息
© 2020 The Authors; exclusive licensee Bio-protocol LLC.
如何引用
Gnangnon, B., Peucelle, V. and Pierrot, C. (2020). Differential Fractionation of Erythrocytes Infected by Plasmodium berghei. Bio-protocol 10(11): e3647. DOI: 10.21769/BioProtoc.3647.
分类
微生物学 > 微生物生物化学 > 蛋白质
微生物学 > 微生物-宿主相互作用 > 体外实验模型
生物化学 > 蛋白质 > 分离和纯化
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