The zebrafish as a novel model for the in vivo study of Toxoplasma gondii replication and interaction with macrophages
The zebrafish as a novel model for the in vivo study of Toxoplasma gondii replication and interaction with macrophages
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DOI：
10.1242/dmm.043091
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发表时间：
2020-07-01
影响因子：
4.3
通讯作者：
Mostowy, Serge
中科院分区：
文献类型：
--
作者：
Yoshida, Nagisa;Domart, Marie-Charlotte;Mostowy, Serge
刚地弓形虫是一种专性细胞内寄生虫，能够侵入任何有核细胞。存在三种主要的克隆谱系（I型，II型，III型），小鼠模型推动了对弓形虫感染的一般和株特异性免疫机制的理解。然而，小鼠模型在研究寄生虫白细胞在体内的相互作用方面是有限的，并且在小鼠和人类细胞中观察到的细胞免疫反应之间存在差异。在此，我们建立了斑马鱼感染模型来研究体内对弓形虫的先天免疫反应。通过感染斑马鱼后脑室，并使用高分辨率显微镜技术结合计算机视觉驱动的自动图像分析，我们发现弓形虫入侵脑细胞并在寄生液泡内复制，I型和III型寄生虫招募宿主细胞线粒体。我们还表明，II型和III型菌株比I型菌株保持更高的感染负担。为了了解寄生虫是如何在体内被清除的，我们使用延时显微镜和三维相关光学和电子显微镜（3D CLEM）进一步分析了弓形巨噬细胞的相互作用。延时显微镜显示巨噬细胞被招募到感染部位并在弓形虫控制中发挥关键作用。高分辨率3D CLEM揭示了体内脑细胞和巨噬细胞的寄生液泡破裂，提示细胞内在机制可能用于破坏细胞内速殖子生态位。总之，我们的研究结果证明了巨噬细胞对弓形虫的体内控制，并强调了斑马鱼可能被进一步开发为寄生虫免疫领域发现的新模型系统的可能性。
Toxoplasma gondii is an obligate intracellular parasite capable of invading any nucleated cell. Three main clonal lineages (type I, II, III) exist and murine models have driven the understanding of general and strain-specific immune mechanisms underlying Toxoplasma infection. However, murine models are limited for studying parasite leukocyte interactions in vivo, and discrepancies exist between cellular immune responses observed in mouse versus human cells. Here, we developed a zebrafish infection model to study the innate immune response to Toxoplasma in vivo. By infecting the zebrafish hindbrain ventricle, and using high-resolution microscopy techniques coupled with computer vision-driven automated image analysis, we reveal that Toxoplasma invades brain cells and replicates inside a parasitophorous vacuole to which type I and III parasites recruit host cell mitochondria. We also show that type II and III strains maintain a higher infectious burden than type I strains. To understand how parasites are cleared in vivo, we further analyzed Toxoplasmamacrophage interactions using time-lapse microscopy and three-dimensional correlative light and electron microscopy (3D CLEM). Time-lapse microscopy revealed that macrophages are recruited to the infection site and play a key role in Toxoplasma control. High-resolution 3D CLEM revealed parasitophorous vacuole breakage in brain cells and macrophages in vivo, suggesting that cell-intrinsic mechanisms may be used to destroy the intracellular niche of tachyzoites. Together, our results demonstrate in vivo control of Toxoplasma by macrophages, and highlight the possibility that zebrafish may be further exploited as a novel model system for discoveries within the field of parasite immunity.