Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-910, Belo Horizonte, Minas Gerais, Brazil.
Aquacen, Escola de Veterinária, Universidade Federal de Minas Gerais, 31270-910, Belo Horizonte, Minas Gerais, Brazil.
Exp Parasitol. 2020 Nov;218:107964. doi: 10.1016/j.exppara.2020.107964. Epub 2020 Aug 19.
Protozoan parasites of the genus Leishmania are causative agents of leishmaniasis, a wide range of diseases affecting 12 million people worldwide. The species L. infantum and L. amazonensis are etiologic agents of visceral and cutaneous leishmaniasis, respectively. Most proteome analyses of Leishmania have been carried out on whole-cell extracts, but such an approach tends to underrepresent membrane-associated proteins due to their high hydrophobicity and low solubility. Considering the relevance of this category of proteins in virulence, invasiveness and the host-parasite interface, this study applied label-free proteomics to assess the plasma membrane sub-proteome of L. infantum and L. amazonensis. The number of proteins identified in L. infantum and L. amazonensis promastigotes was 1168 and 1455, respectively. After rigorous data processing and mining, 157 proteins were classified as putative plasma membrane-associated proteins, of which 56 proteins were detected in both species, six proteins were detected only in L. infantum and 39 proteins were exclusive to L. amazonensis. The quantitative analysis revealed that two proteins were more abundant in L. infantum, including the glucose transporter 2, and five proteins were more abundant in L. amazonensis. The identified proteins associated with distinct processes and functions. In this regard, proteins of L. infantum were linked to metabolic processes whereas L. amazonensis proteins were involved in signal transduction. Moreover, transmembrane transport was a significant process among the group of proteins detected in both species and members of the superfamily of ABC transporters were highly represented. Interestingly, some proteins of this family were solely detected in L. amazonensis, such as ABCA9. GP63, a well-known virulence factor, was the only GPI-anchored protein identified in the membrane preparations of both species. Finally, we found several proteins with uncharacterized functions, including differentially abundant ones, highlighting a gap in the study of Leishmania proteins. Proteins characterization could provide a better biological understanding of these parasites and deliver new possibilities regarding the discovery of therapeutic targets, drug resistance and vaccine candidates.
原生动物利什曼原虫属的寄生虫是利什曼病的病原体，这种疾病影响着全球 1200 万人。L. infantum 和 L. amazonensis 分别是内脏利什曼病和皮肤利什曼病的病原体。大多数利什曼原虫的蛋白质组分析都是在全细胞提取物上进行的，但由于其高度疏水性和低溶解度，这种方法往往会低估膜相关蛋白。考虑到这一类蛋白质在毒力、侵袭性和宿主-寄生虫界面中的相关性，本研究应用无标记蛋白质组学来评估 L. infantum 和 L. amazonensis 的质膜亚蛋白组。在 L. infantum 和 L. amazonensis 前鞭毛体中鉴定到的蛋白质数量分别为 1168 和 1455。经过严格的数据处理和挖掘，将 157 种蛋白质分类为推定的质膜相关蛋白，其中 56 种蛋白质在两种物种中均有检测到，6 种蛋白质仅在 L. infantum 中检测到，39 种蛋白质仅在 L. amazonensis 中检测到。定量分析显示，两种蛋白质在 L. infantum 中更为丰富，包括葡萄糖转运蛋白 2，而五种蛋白质在 L. amazonensis 中更为丰富。鉴定到的与不同过程和功能相关的蛋白质。在这方面，L. infantum 的蛋白质与代谢过程有关，而 L. amazonensis 的蛋白质则与信号转导有关。此外，跨膜运输是两种物种中检测到的蛋白质组中的一个重要过程，ABC 转运蛋白超家族的成员高度代表。有趣的是，该家族的一些蛋白质仅在 L. amazonensis 中检测到，例如 ABCA9。GP63 是一种众所周知的毒力因子，是两种物种膜制剂中唯一鉴定到的 GPI-锚定蛋白。最后，我们发现了一些具有未知功能的蛋白质，包括丰度差异较大的蛋白质，这突显了利什曼原虫蛋白质研究的一个空白。蛋白质的特征可以提供对这些寄生虫更好的生物学理解，并为发现治疗靶点、药物抗性和疫苗候选物提供新的可能性。
