Exploring the potential to improve azole efficacy against Trypanosoma cruzi by targeting glutamine metabolism

项目摘要 众所周知，查加斯病寄生虫克氏锥虫的慢性感染很难用 目前的药物治疗方案。对T. cruzi感染是未知的，但这仍然是 这个领域最紧迫的问题之一在药物失败的潜在解释中， 异质性代谢环境可能在T. cruzi，尚未被探索。 最近，我们发现了谷氨酰胺代谢和一组杀锥虫作用之间的新联系， 唑类化合物靶向T.克鲁兹无鞭毛体。我们发现，在限制条件下， 谷氨酰胺的利用率，细胞内无鞭毛体存活暴露于致死浓度的唑类，包括 泊沙康唑，一种不能清除T.克氏锥虫感染的临床研究 审判鉴于谷氨酰胺水平在胃肠道区域最低的证据， 已知寄生虫在唑类药物治疗后持续存在和复发，我们的新发现可能具有重要意义。 泊沙康唑未能清除小鼠和慢性恰加斯病患者的寄生虫感染。的 这项探索性R21提案的目的是确定获得外源性谷氨酰胺的机制， 调节胞内T细胞的唑依赖性杀伤。cruzi无鞭毛体，并确定化合物在小 在谷氨酰胺条件下特异性消除寄生虫对唑类保护的分子库筛选 文化的限制。这项研究的结果有可能揭示辅助谷氨酰胺敏感途径 在低谷氨酰胺环境下，可以靶向增强唑类药物的疗效， 这些化合物将成为未来功能研究的有力工具。

PROJECT SUMMARY Chronic infections with the Chagas disease parasite, Trypanosoma cruzi, are notoriously difficult to treat with the current drug regimens. The mechanism(s) underlying recalcitrant T. cruzi infection are unknown, but this remains one of the most pressing problems in the field. Of the potential explanations for drug failure, the role that heterogeneous metabolic environments might play in drug susceptibility in T. cruzi, has not been explored. Recently, we discovered a novel link between glutamine metabolism and the trypanocidal action of a group of azole compounds that target sterol biosynthesis in T. cruzi amastigotes. We find that under conditions of limiting glutamine availability, intracellular amastigotes survive exposure to lethal concentrations of azoles, including posaconazole, a drug that failed to clear T. cruzi infection from chronically-infected Chagas patients in clinical trials. Given evidence that glutamine levels are lowest in the region of the gastrointestinal tract that these parasites are known to persist and recrudesce following azole treatment, our novel findings may have important implications for the failure of posaconazole to clear parasite infection in mice and chronic Chagas patients. The goals of this exploratory R21 proposal are to define the mechanism(s) by which access to exogenous glutamine modulates azole-dependent killing of intracellular T. cruzi amastigotes and to identify compounds in small molecule library screens that specifically ablate parasite protection from azoles under conditions of glutamine restriction in culture. Results from this study have the potential to reveal auxiliary glutamine-sensitive pathways in the parasite that can be targeted to potentiate the efficacy of azoles in low glutamine settings as well a set of compounds that will serve as powerful tools for future functional studies.