Pessoa Carina Carraro, Ferreira Éden Ramalho, Bayer-Santos Ethel, Rabinovitch Michel, Mortara Renato Arruda, Real Fernando
Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, UNIFESP, São Paulo, Brazil.
Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, UNIFESP, São Paulo, Brazil
Infect Immun. 2016 Apr 22;84(5):1603-1614. doi: 10.1128/IAI.01470-15. Print 2016 May.
The trypanosomatids Leishmania amazonensis and Trypanosoma cruzi are excellent models for the study of the cell biology of intracellular protozoan infections. After their uptake by mammalian cells, the parasitic protozoan flagellates L. amazonensis and T. cruzi lodge within acidified parasitophorous vacuoles (PVs). However, whereas L. amazonensis develops in spacious, phagolysosome-like PVs that may enclose numerous parasites, T. cruzi is transiently hosted within smaller vacuoles from which it soon escapes to the host cell cytosol. To investigate if parasite-specific vacuoles are required for the survival and differentiation of T. cruzi, we constructed chimeric vacuoles by infection of L. amazonensis amastigote-infected macrophages with T. cruzi epimastigotes (EPIs) or metacyclic trypomastigotes (MTs). These chimeric vacuoles, easily observed by microscopy, allowed the entry and fate of T. cruzi in L. amazonensis PVs to be dynamically recorded by multidimensional imaging of coinfected cells. We found that although T. cruzi EPIs remained motile and conserved their morphology in chimeric vacuoles, T. cruzi MTs differentiated into amastigote-like forms capable of multiplying. These results demonstrate that the large adaptive vacuoles of L. amazonensis are permissive to T. cruzi survival and differentiation and that noninfective EPIs are spared from destruction within the chimeric PVs. We conclude that T. cruzi differentiation can take place in Leishmania-containing vacuoles, suggesting this occurs prior to their escape into the host cell cytosol.
锥虫利什曼原虫亚马逊亚种和克氏锥虫是研究细胞内原生动物感染细胞生物学的优秀模型。被哺乳动物细胞摄取后，寄生原生动物鞭毛虫亚马逊利什曼原虫和克氏锥虫寄生于酸化的寄生泡（PVs）内。然而，亚马逊利什曼原虫在宽敞的、类似吞噬溶酶体的PVs中发育，其中可能包含许多寄生虫，而克氏锥虫则短暂地寄生于较小的液泡中，随后很快逸出到宿主细胞胞质溶胶中。为了研究克氏锥虫的存活和分化是否需要寄生虫特异性液泡，我们通过用克氏锥虫的前鞭毛体（EPIs）或循环后锥鞭毛体（MTs）感染被亚马逊利什曼原虫无鞭毛体感染的巨噬细胞，构建了嵌合液泡。这些嵌合液泡通过显微镜很容易观察到，通过对共感染细胞的多维成像，可以动态记录克氏锥虫在亚马逊利什曼原虫PVs中的进入和命运。我们发现，尽管克氏锥虫EPIs在嵌合液泡中仍保持运动并保留其形态，但克氏锥虫MTs分化为能够增殖的无鞭毛体样形式。这些结果表明，亚马逊利什曼原虫的大型适应性液泡允许克氏锥虫存活和分化，并且非感染性EPIs在嵌合PVs中免受破坏。我们得出结论，克氏锥虫的分化可以在含有利什曼原虫的液泡中发生，这表明这种情况发生在它们逸出到宿主细胞胞质溶胶之前。
