Kessler Rafael Luis, Contreras Víctor Tulio, Marliére Newmar Pinto, Aparecida Guarneri Alessandra, Villamizar Silva Luz Helena, Mazzarotto Giovanny Augusto Camacho Antevere, Batista Michel, Soccol Vanete Thomaz, Krieger Marco Aurelio, Probst Christian Macagnan
Instituto Carlos Chagas, FIOCRUZ, Curitiba, PR, Brazil.
Laboratorio de Protozoología, Centro de Biología Molecular de Parásitos, Facultad Ciencias de la Salud, Universidad de Carabobo, Valencia, Venezuela.
Mol Microbiol. 2017 Jun;104(5):712-736. doi: 10.1111/mmi.13653. Epub 2017 May 9.
Trypanosoma cruzi, the etiologic agent of Chagas disease, has a complex life cycle in which four distinct developmental forms alternate between the insect vector and the mammalian host. It is assumed that replicating epimastigotes present in the insect gut are not infective to mammalian host, a paradigm corroborated by the widely acknowledged fact that only this stage is susceptible to the complement system. In the present work, we establish a T. cruzi in vitro and in vivo epimastigogenesis model to analyze the biological aspects of recently differentiated epimastigotes (rdEpi). We show that both trypomastigote stages of T. cruzi (cell-derived and metacyclic) are able to transform into epimastigotes (processes termed primary and secondary epimastigogenesis, respectively) and that rdEpi have striking properties in comparison to long-term cultured epimastigotes: resistance to complement-mediated lysis and both in vitro (cell culture) and in vivo (mouse) infectivity. Proteomics analysis of all T. cruzi stages reveled a cluster of proteins that were up-regulated only in rdEpi (including ABC transporters and ERO1), suggesting a role for them in rdEpi virulence. The present work introduces a new experimental model for the study of host-parasite interactions, showing that rdEpi can be infective to the mammalian host.
克氏锥虫是恰加斯病的病原体，其生命周期复杂，在昆虫媒介和哺乳动物宿主之间交替出现四种不同的发育形式。一般认为，存在于昆虫肠道中的增殖型上鞭毛体对哺乳动物宿主无感染性，这一范式得到了广泛认可的事实的佐证，即只有这个阶段易受补体系统影响。在本研究中，我们建立了克氏锥虫的体外和体内上鞭毛体生成模型，以分析新分化的上鞭毛体（rdEpi）的生物学特性。我们发现，克氏锥虫的两种锥鞭毛体阶段（细胞衍生型和循环后期型）都能够转化为上鞭毛体（分别称为初级和次级上鞭毛体生成过程），并且与长期培养的上鞭毛体相比，rdEpi具有显著特性：对补体介导的裂解具有抗性，以及在体外（细胞培养）和体内（小鼠）均具有感染性。对克氏锥虫所有阶段的蛋白质组学分析揭示了一组仅在rdEpi中上调的蛋白质（包括ABC转运蛋白和ERO1），表明它们在rdEpi毒力中发挥作用。本研究引入了一种用于研究宿主-寄生虫相互作用的新实验模型，表明rdEpi可感染哺乳动物宿主。
