Dual artemisinin action combats resistance

青蒿素双重作用对抗耐药性

基本信息

批准号：
10211154
负责人：
DAVID Joseph SULLIVAN
金额：
$ 58.54万
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，以最大程度地通过击败抵抗，杀死恶性疟原虫寄生虫。在持续抵抗当前的情况下部署的药物，这项工作将量化一种新型的喹啉样作用机理定义可逆或不可逆的血红素晶体抑制与耐药性水平相关，并探索最佳血红素晶体抑制与用喹啉 - 阿蒂米花蛋白组合杀死寄生虫有关的抑制作用。初步数据验证基于丰富的血红素 - 艺术蛋白的形成，促男氨甲蛋白素的其他作用机理，通过不可逆转的作用抑制血红素结晶。外源性血红素 - 甲蛋白加合物抑制阿己辛蛋白抗环突变体Kelch13 P. NM IC50较低的恶性寄生虫。实验方法采用在体外对恶性疟原虫药物敏感和抗性寄生虫进行实验研究之间的协同作用通过原子力显微镜对晶体生长的原位观察获得的物理见解在存在不同的药物组合的情况下。假设是通过二氢甲蛋白的血红素加合物对血红素晶体形成的抑制（dha，dha，dha，大多数青蒿素级药物在体内的产物使任何疟原虫分离株敏感的滋养体具有击败阿美米辛蛋白环阶段的抵抗力。我们还假设奎诺琳和血红素 - 二氢甲蛋白加合物（H-DHA）在杀死与血红素晶体抑制相关的寄生虫方面优越并分别达到可逆/不可逆的血红素晶体抑制程度。朝向这些目标，我们将追求三个具体目标：目标1。建立外源性的抑制浓度和作用机理以及在药物敏感和抗性疟原虫中的生物激活的H-DHA。目标2。建立可逆性或不可逆性 H-DHA血红素晶体在体内和体外的抑制作用。目标3。确定抗疟疾喹啉的双重组合和H-DHA加合物增强，弱或对伴侣对寄生虫杀戮的行动无动于衷血蛋白结晶。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对青蒿素药物类敏感。这项工作还将为基本知识提供信息关于击败青蒿素耐药性的机制，血蛋白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。