Dual artemisinin action combats resistance

青蒿素双重作用对抗耐药性

基本信息

批准号：
10581538
负责人：
DAVID Joseph SULLIVAN
金额：
$ 56.94万
依托单位：
JOHNS HOPKINS UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-03-18 至 2026-02-28
项目状态：
未结题

项目摘要

Summary The broad long-term goal is to optimize critical artemisinin and quinoline malaria drug combinations for maximum killing of the P. falciparum parasite by defeating resistance. In the setting of ongoing drug resistance to currently deployed drugs, this work will quantify a novel quinoline-like mechanism of action for the heme-artemisinin adducts, define reversible or irreversible heme crystal inhibition correlated to level of drug resistance, and explore optimum heme crystal inhibition related to parasite killing with quinoline-artemisinin combinations. Preliminary data validate an additional mechanism of action for the artemisinins based on formation of abundant heme-artemisinin adduct, which inhibits heme crystallization with irreversible action. Exogenous heme-artemisinin adducts inhibit artemisinin ring-resistant mutant Kelch13 P. falciparum parasites with low nM IC50s. The experimental approach employs the synergy between experimental investigations with P. falciparum drug-sensitive and resistant parasites in vitro and physicochemical insights obtained by time-resolved in situ observations of crystal growth by atomic force microscopy in the presence of different drug combinations. The hypothesis is that the inhibition of heme crystal formation by the heme adduct of dihydroartemisinin (DHA, the product of most artemisinin-class drugs in vivo) renders trophozoites of any Plasmodium isolate sensitive, which defeats the artemisinin ring-stage resistance. We also hypothesize that certain combinations of quinolines and heme-dihydroartemisinin adduct (H-DHA) are superior in killing of parasites correlated to heme crystal inhibition as well as separately to the degree of reversible/irreversible heme crystal inhibition. Towards these objectives, we will pursue three specific aims: Aim 1. Establish the inhibition concentrations and mechanism of action of exogenous as well as bio-activated H-DHA in drug sensitive and resistant Plasmodium. Aim 2. Establish reversibility or irreversibility of H-DHA heme crystal inhibition in vivo and in vitro. Aim 3. Establish if double combinations of antimalarial quinolines and H-DHA adducts enhance, weaken, or are indifferent to their partner’s action on parasite killing and the rate of hematin crystallization. This proposed research will quantify the amount of parasite killing by artemisinin adduct metabolites which renders trophozoite stages sensitive to the artemisinin drug class. The work will also inform fundamental knowledge regarding mechanisms to defeat artemisinin resistance, degree of reversibility of hematin crystal growth, and optimum combinations of malaria drugs based upon interaction effects.

概括广泛的长期目标是优化关键的青蒿素和喹啉疟疾药物组合，以最大程度地发挥作用在目前持续存在耐药性的情况下，通过击败耐药性来杀死恶性疟原虫。部署后，这项工作将量化药物的血红素-青蒿素加合物的新型喹啉样作用机制，定义与耐药水平相关的可逆或不可逆血红素晶体抑制，并探索最佳初步数据验证了与喹啉-青蒿素组合杀灭寄生虫相关的血红素晶体抑制作用。青蒿素的另一种作用机制基于丰富的血红素-青蒿素加合物的形成，它以不可逆的作用抑制血红素结晶。具有低 nM IC50 的抗环突变体 Kelch13 恶性疟原虫实验方法采用恶性疟原虫药物敏感和耐药寄生虫体外实验研究和通过原子力显微镜对晶体生长进行时间分辨原位观察获得的物理化学见解在存在不同药物组合的情况下。假设是二氢青蒿素（DHA，大多数青蒿素类药物体内的产物）使任何疟原虫分离株的滋养体敏感，这我们还发现了喹啉和青蒿素的某些组合。血红素-二氢青蒿素加合物 (H-DHA) 在杀死与血红素晶体抑制相关的寄生虫方面具有优越性，因为以及可逆/不可逆血红素晶体抑制的程度，我们将实现这些目标。追求三个具体目标：目标 1. 建立外源性 as 的抑制浓度和作用机制以及药物敏感和耐药疟原虫中的生物活化 H-DHA 目标 2. 确定可逆性或不可逆性。目标 3. 建立抗疟喹啉的双重组合。 H-DHA 加合物增强、减弱或不影响其伴侣杀死寄生虫的作用以及杀灭寄生虫的速度。血红素结晶。这项拟议的研究将量化青蒿素加合物代谢物杀死寄生虫的量，使滋养体阶段对青蒿素类药物敏感。这项工作还将提供基础知识。关于击败青蒿素耐药性的机制、血红素晶体生长的可逆性程度，以及基于相互作用效应的疟疾药物的最佳组合。