Intracellular Proliferation of the fungal pathogen Histoplasma capsulatum

真菌病原体荚膜组织胞浆菌的细胞内增殖

基本信息

批准号：
10583569
负责人：
Chad A Rappleye
金额：
$ 37.45万
依托单位：
OHIO STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-03-10 至 2025-02-28
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10583569
关键词：
Address Amino Acid Permease Amino Acid Transporter Amino Acids Attenuated Carbon Catabolism Cells Citric Acid Cycle Coccidioidomycosis Complement Consumption Data Diagnosis Disease Environment Enzymes Funding Opportunities Genes Genetic Genetic Screening Genetic Transcription Genus Hippocampus Gluconeogenesis Glutamate Dehydrogenase Glutamates Glycolysis Goals Growth Histoplasma Histoplasma capsulatum Histoplasmosis Immune system Immunocompetent Immunocompromised Host Impairment In Vitro Individual Infection Innate Immune System Invaded Investigation Isotope Labeling Lung Macrophage Measurement Metabolic Metabolic Pathway Metabolism Mitochondria Molecular Molecular Biology Molecular Genetics Mutation Mycoses Nutrient Nutritional Nutritional Requirements Pathogenesis Pathway interactions Peptides Phagocytes Phagosomes Proliferating RNA Interference Reaction Resources Respiration Respiratory Disease Saccharomyces cerevisiae Source Substrate Specificity Systemic disease Testing Therapeutic Time Virulence Yeasts alpha ketoglutarate desert fever fungus genetic testing in vivo interdisciplinary approach metabolic profile metabolomics mouse model mutant new therapeutic target novel strategies novel therapeutics parasitism pathogen pathogenic fungus permissiveness prevent residence response transcriptomics uptake

项目摘要

PROJECT SUMMARY Histoplasma capsulatum is a fungal pathogen that infects both immunocompromised and immunocompetent individuals. The innate immune system alone is ineffective in controlling Histoplasma yeasts because Histoplasma invades and thrives within host phagocytic cells. Histoplasma’s parasitism of macrophages requires acquisition and metabolism of suitable nutritional resources from the host cell, yet the host molecules that serve as nutrients for are largely unknown. Preliminary investigations have shown intracellular yeasts are gluconeogenic and likely consume amino acids, particularly compounds that are related to glutamate. These findings provide a critical foothold for identifying the host molecules consumed by Histoplasma yeasts. This proposal takes a multidisciplinary approach, integrating evidence from molecular biology, genetics, and metabolomics to determine the host molecules available to Histoplasma yeasts within the phagosome and how they are metabolized to meet the carbon and energy needs within host cells. The intracellular growth requirement for glutamate dehydrogenase activity narrows the potential host molecules for metabolic carbon to glutamate-related amino acids or glutamate-generating host molecules. Transcriptional and metabolite profiling will be combined with functional tests to define the metabolic pathways necessary for Histoplasma proliferation within host macrophages. Isotopic labeling of host metabolites will be used to follow their import and subsequent incorporation into Histoplasma metabolism intermediates over time to demonstrate the flux of carbon from macrophage to intracellular yeasts and identify host substrate entry points into yeast central carbon metabolism. These findings will be genetically tested by characterization of Histoplasma’s amino acid and peptide transporters and RNAi-based interference with candidate host metabolite import into intracellular Histoplasma yeast cells. Together these data will provide multiple lines of evidence to define how Histoplasma yeasts exploit the phagosome as a replication-permissive intracellular niche during host infection. This proposal is submitted in response to Funding Opportunity Announcement (FOA) PA-19-083 “Novel approaches to understand, prevent, treat, and diagnose coccidioidomycosis (Valley Fever) and other select endemic fungal infections.” The proposal answers the announcement’s goal to address the pathogenesis of endemic fungi with the ultimate goal of advancing the field towards solutions for treatment of endemic mycoses. Of the dimorphic endemic fungal pathogens, Histoplasma is the best molecularly characterized fungus and it has the most advanced molecular genetics to facilitate functional testing for mechanistic studies. The results of our studies will reveal new disease treatment avenues by highlighting transport and metabolic reactions essential for the narrow metabolism imposed on Histoplasma by its residence within macrophage phagosomes. Our genetic tests have shown that impairment of these critical metabolic reactions reduces Histoplasma proliferation in the mammalian lung, demonstrating the therapeutic potential.

项目概要荚膜组织胞浆菌是一种真菌病原体，可感染免疫功能低下和免疫功能正常的人单独的先天免疫系统无法有效控制组织胞浆菌，因为组织胞浆菌侵入宿主吞噬细胞并在其寄生的巨噬细胞内繁殖。需要从宿主细胞获取和代谢合适的营养资源，但宿主分子初步研究表明，细胞内酵母的营养成分很大程度上是未知的。糖异生并可能消耗氨基酸，特别是与谷氨酸相关的化合物。这些发现为识别组织胞浆菌消耗的宿主分子提供了关键的立足点。该提案采用多学科方法，整合了分子生物学、遗传学和代谢组学确定吞噬体内组织胞浆菌可用的宿主分子以及如何它们被代谢以满足宿主细胞内的碳和能量需求。对谷氨酸脱氢酶活性的要求缩小了代谢碳的潜在宿主分子范围谷氨酸相关氨基酸或谷氨酸生成宿主分子。分析将与功能测试相结合，以确定组织胞浆菌所需的代谢途径宿主巨噬细胞内的增殖将使用宿主代谢物的同位素标记来追踪其输入。并随后随着时间的推移并入组织胞浆菌代谢中间体中，以证明从巨噬细胞到细胞内酵母的碳，并识别酵母中枢的宿主底物入口点这些发现将通过组织胞浆菌氨基酸的表征进行基因测试。肽转运蛋白和基于 RNAi 的干扰候选宿主代谢物进入细胞内组织胞浆菌酵母细胞。这些数据将为定义组织胞浆菌如何产生提供多种证据。酵母在宿主感染期间利用吞噬体作为允许复制的细胞内生态位。本提案是为了响应资助机会公告 (FOA) PA-19-083“Novel 了解、预防、治疗和诊断球孢子菌病（谷热）和其他选择的方法该提案回应了该公告的目标，即解决地方性真菌感染的发病机制。地方性真菌的最终目标是推动该领域找到治疗地方性真菌的解决方案在二态性地方性真菌病原体中，组织胞浆菌是分子特征最好的。真菌，它具有最先进的分子遗传学，可促进机械研究的功能测试。我们的研究结果将通过强调运输和代谢来揭示新的疾病治疗途径组织胞浆菌驻留在巨噬细胞内，对组织胞浆菌进行狭窄代谢所必需的反应我们的基因测试表明，这些关键代谢反应的损害会减少。哺乳动物肺部的组织胞浆菌增殖，证明了其治疗潜力。