Mechanistic analysis of Toxoplasma gondii sexual development in tissue culture and mouse models

项目概要 弓形虫是弓形虫病的病原体，弓形虫病是食源性疾病导致死亡的主要原因 这会导致免疫功能低下的个体患上严重疾病。该寄生虫无性发育并且 有性和无性寄生虫的发育已得到充分研究。然而，寄生虫完成了性阶段 仅存在于猫的肠上皮中，对性阶段提出了重大的伦理和后勤障碍 研究。消除对伴侣动物研究的需要并研究性阶段的未知生物学 弓形虫，我们的实验室开发了支持弓形虫性发育的小鼠和组织培养模型。的 多不饱和脂肪酸亚油酸是弓形虫完成性发育的关键因素 在猫科动物肠道中独特升高。亚油酸作用于宿主或寄生虫的机制仍然存在 未知。该提案的目标是确定亚油酸促进弓形虫性的机制 细胞培养和体内发育。我们小组和其他人的初步数据表明，亚油酸 对宿主和寄生虫都起作用，以促进弓形虫性发育的宽松环境。我 假设细胞内亚油酸的积累激活弓形虫脂质信号通路 促进性发育。我进一步假设性发育依赖于类似的激活 宿主内的信号通路。在目标 1 中，我将确定亚油酸对寄生虫的作用机制 通过测量寄生虫对亚油酸处理的转录反应。我还将测试我们的新鼠标模型 亚油酸积累的能力能够促进弓形虫体内有效的性发育。在目标 2 中，我 将使用自动图像分析来确定宿主细胞类型在弓形虫性中的重要性 发展。 siRNA 介导的亚油酸反应性宿主因子的消除将鉴定出以下宿主基因： 影响性发育。成功完成这些目标将更好地定义亚油酸如何实现 弓形虫有性阶段的生长。这项工作的长期意义是建立一个可共享的弓形虫模型 性发育将有助于减轻弓形体病的负担。

Project Summary Toxoplasma gondii is the causative agent of toxoplasmosis, a leading cause of death due to foodborne illness that causes serious disease in immunocompromised individuals. The parasite develops asexually and sexually, and asexual parasite development is well-studied. However, the parasite completes its sexual stage only in the cat intestinal epithelium, presenting a significant ethical and logistical barrier to sexual stage research. To remove the need for companion animal research and study the unknown biology of sexual stage T. gondii, our lab developed murine and tissue culture models that support T. gondii sexual development. The polyunsaturated fatty acid linoleic acid is a critical factor for T. gondii to complete sexual development that is uniquely elevated in the feline intestine. The mechanisms by which linoleic acid acts on host or parasite remain unknown. The goal of this proposal is to determine the mechanism of linoleic acid in promoting T. gondii sexual development in cell culture and in vivo. Preliminary data from our group and others suggests that linoleic acid acts on both host and parasite to promote a permissive environment for T. gondii sexual development. I hypothesize that intracellular accumulation of linoleic acid activates T. gondii lipid signaling pathways to promote sexual development. I further hypothesize that sexual development relies on activation of similar signaling pathways in the host. In Aim 1, I will determine the mechanism of linoleic acid action on the parasite by measuring parasite transcriptional responses to linoleic acid treatment. I will also test our new mouse model of linoleic acid accumulation for its ability to promote efficient T. gondii sexual development in vivo. In Aim 2, I will use automated image analysis to determine the importance of host cell type in T. gondii sexual development. siRNA-mediated ablation of linoleic acid-responsive host factors will identify host genes that influence sexual development. Successful completion of these Aims will better define how linoleic acid enables growth of T. gondii sexual stages. The long-term implication of this work is a shareable model of T. gondii sexual development that will help reduce the burden of toxoplasmosis.