Role of host cell metabolism in supporting intracellular Trypanosma cruzi growth

描述（由申请人提供）：克氏锥虫是引起人类恰加斯病的原生动物寄生虫，是一种专性细胞内病原体，在其哺乳动物宿主细胞的细胞质中生存和分裂。尽管它在组织感染、持久性和疾病中很重要，但目前对克氏T细胞内无梭体期的生物学知之甚少。特别是，宿主细胞对支持克氏锥虫细胞内复制和存活的重要贡献在很大程度上仍然未知。为了鉴定细胞内T. cruzi感染的关键热细胞调节因子，我的实验室建立并进行了高通量全基因组功能筛选，以鉴定作为细胞内寄生虫生长调节因子的宿主细胞途径/过程。宿主细胞脂肪酸代谢出现在

DESCRIPTION (provided by applicant): Trypanosoma cruzi, the protozoan parasite that causes human Chagas' disease, is an obligate intracellular pathogen that lives and divides in the cytoplasm of its mammalian host cell. Despite its importance in tissue infection, persistence and disease, little is currently known about the biology of the intracellular amastigote stage of T cruzi. In particular, the essential contributions of the host cell toward the support of intracelluar replication and survival of T. cruzi remain largely unknown. With a view to identifying critical hot cell regulators of intracellular T. cruzi infection, my laboratory has established and conducted a high-throughput genome-wide functional screen to identify host cell pathways/processes that function as regulators of intracellular parasite growth. Host cell fatty acid metabolism emerged in this screen as a major pathway regulating growth of intracellular T. cruzi amastigotes in HeLa cells. We also made the observation that intracellular T. cruzi amastigotes sequester host cell glycogen, where glycogen particles are highly enriched in the vicinity of the cytosolic amastigotes. These novel findings are strongly suggestive of the ability of T. cruzi to modulate host metabolic functions in infected host cells. In support of this hypothesis, PDK4, the main regulator of the shift between glucose and fatty acid utilization in cells (favoring fatty acid utilization) was shown to be important for supporting intracellular T. cruzi growth. This is intriguing given that T. cruzi exhibit tropism in vivo for muscle cells that are biased toward fatt acid utilization. While many of the tools exist to study metabolism in mammalian cells, these tools have yet to be applied to the study of host cell metabolism in the context of T. cruzi infection. Thus, the aim of this exploratory R21 proposal is to establish an experimental framework with methodologies and tools developed primarily for studies of metabolic disease (diabetes, cancer etc) that will allow us to determine the extent to which host cell metabolism is altered in T. cruzi-infected host cells and how this impacts intracellular parasite growth. Understanding the intimate relationship between host metabolism and T. cruzi amastigote growth will provide a critical piece of biology that is currently lacking in our knowledge of T. cruzi-host interactions and will help to elucidate novel targets for the control of T. cruzi growth