Role of amylopectin granules in chronic toxoplasmosis, an HIV-AIDS defining infection

支链淀粉颗粒在慢性弓形体病（一种 HIV-AIDS 感染）中的作用

基本信息

批准号：
10025481
负责人：
ANTHONY P. SINAI
金额：
$ 19.13万
依托单位：
UNIVERSITY OF KENTUCKY
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：
2020-03-05 至 2022-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10025481
关键词：
Acquired Immunodeficiency Syndrome Acute Address Amylopectin Anabolism Apicomplexa Biochemical Biochemistry Biological Biology Characteristics Charge Chemicals Chronic Chronic Phase Clinical Cyst Cytoplasmic Granules Development Disease Energy-Generating Resources Enzymes Event Future Genome Glucans Glucose Glucose-6-Phosphate Glutamine Glycogen Glycogen (Starch) Synthase Growth HIV Human Immune system Immunosuppression Individual Infection Kinetics Knock-out Laboratories Length Link Location Maintenance Mediating Metabolism Morphology Parasites Parasitic infection Pharmaceutical Preparations Phase Phosphorylation Physiological Plants Play Polymers Population Process Production Publishing Regulation Resources Role Signal Transduction Starch Testing Therapeutic Intervention Tissues Toxoplasma Toxoplasma gondii Toxoplasmosis Uridine Diphosphate Sugars Work acute infection asexual chronic infection crystallinity glucose 1 phosphate imaging approach in vivo insight knock-down metabolomics mutant novel quantitative imaging sugar nucleotide tool transmission process

项目摘要

Project Summary A distinguishing characteristic of tissue cyst forming Apicomplexa, like Toxoplasma gondii, is the accumulation of amylopectin (starch) granules (AG) within bradyzoites and their absence within the actively growing tachyzoite forms. As polymers of glucose, AG functions as a battery serving as a reserve for energy production and biosynthetic functions. Our recent work established that bradyzoites retain significant replicative potential within tissue cysts in vivo. Notably, most bradyzoite replication within tissue cysts occurs asynchronously with clustered bursts of growth interceded with non-replicative periods. While the specific signals triggering these bursts remain unknown, what is clear is that they would require substantial energy and metabolite inputs to execute. Historical evidence and our findings reveal that AG levels within encysted bradyzoites are highly variable with clusters of parasites lacking AGs adjacent to others that are loaded with starch. This suggests that AG metabolism involving both synthesis and turnover are active within tissue cysts and may play a central role in the progression of chronic toxoplasmosis. We will directly address the dynamics and biological contributions of AGs in the progression of the chronic infection at the level of individual bradyzoites using novel tools and concepts developed in our recently published work. The variable levels of AG, within encysted bradyzoites, suggest that both AG accumulation and depletion are under regulatory control. Indeed the enzymatic machinery required for both the synthesis and regulated turnover of starch are encoded in the Toxoplasma genome. We will directly test the importance of AG in the acute infection, the regulation of stage conversion and the establishment/ progression of the chronic infection by targeting the commitment enzyme for starch synthesis, the UDP-glucose pyrophosphorylase (TgUDP-GPP, TgME49_218200), and the starch synthase (TgSS, TgME49_222800). Recent evidence suggests that despite being morphologically (though not biochemically) detectable, amylopectin may play a role in tachyzoite intermediary metabolism as well. In addition, the contribution of AG's to reactivation, the primary trigger of symptomatic disease in HIV-AIDS will be addressed in the context of induced immune suppression. With the proposed studies we aim to dissect the previously unexplored role of AG in tachyzoites, as factors in tachyzoite to bradyzoite conversion, the progression of the chronic infection and clinically critical reactivation in vivo. These studies will establish the groundwork for targeting AG metabolism for therapeutic intervention in the chronic infection where the paucity of effective drugs remains a significant issue in the clinical context of HIV-AIDS.

项目摘要组织囊肿形成apicomplexa的区别特征，例如弓形虫弓形虫，是积累链氨基蛋白（淀粉）颗粒（Ag）的粒子及其在积极生长中的缺失 tachyzoite形式。作为葡萄糖的聚合物，AG充当电池，充当能源生产的储备和生物合成功能。我们最近的工作确定，Bradyzoites保留了巨大的复制潜力在体内组织囊肿内。值得注意的是，组织囊肿内的大多数铁二核复制是不同步的簇状的生长爆发与非复制期有关。而特定的信号触发这些爆发仍然未知，清楚的是，它们需要大量的能量和代谢物输入执行。历史证据和我们的发现表明，百科全书中的Ag水平高度高与其他装有淀粉的其他寄生虫相邻的寄生虫簇的变量。这暗示着涉及合成和周转的Ag代谢在组织囊肿中活跃，并且可能发挥中心在慢性弓形虫病的进展中的作用。我们将直接解决动力和生物学使用新颖在我们最近发表的工作中开发的工具和概念。 Ag的可变水平，在encysted中 Bradyzoites表明，Ag积累和耗竭均受到调节控制。确实是淀粉的合成和调节营业额所需的酶促机器均编码弓形虫基因组。我们将直接测试AG在急性感染中的重要性通过靶向承诺酶的转化和慢性感染的建立/进展淀粉合成，UDP-葡萄糖焦磷酸化酶（TGUDP-GPP，TGME49_218200）和淀粉合酶（TGSS，TGME49_222800）。最近的证据表明，尽管在形态上是可检测到的淀粉蛋白在生化上也可能在速杀中介代谢中发挥作用。在此外，Ag对重新激活的贡献，艾滋病毒aid中有症状疾病的主要触发因素将是在诱导的免疫抑制背景下解决。通过拟议的研究，我们旨在剖析以前未开发的Ag在tachyzoites中的作用，作为tachyzoite的因素到bradyzoite转化，慢性感染和体内临床关键重新激活的进展。这些研究将确定靶向Ag代谢进行治疗干预的基础，在慢性感染中在HIV-AID的临床背景下，有效的药物仍然是一个重要的问题。