RhopH蛋白调控恶性疟原虫H-铁蛋白代谢的分子机制

疟疾是严重危害人类健康的寄生虫病。疟原虫寄居的红细胞处于严重的氧化应激状态，铁稳态是其存活的关键。然而，恶性疟原虫既不表达铁蛋白，也不表达已知的铁蛋白受体，其储存和解毒过量铁的机制尚不清楚。课题组前期研究发现，红内期恶性疟原虫可特异获取H-铁蛋白（HFn），免疫荧光结果显示HFn在原虫中的分布与高分子量棒状体蛋白(RhopH)相同，且抗RhopH2抗体可特异地抑制疟原虫对HFn的摄取，由此推测RhopH具有调控恶性疟原虫HFn代谢的作用。因此，本项目拟通过Cos7细胞模型和表面等离子共振进行蛋白互作分析，鉴定与HFn互作的RhopH成员及其功能域；通过质谱及生物信息学分析，筛选对RhopH有协同作用的膜蛋白；并通过蛋白定位、抗体抑制，及氧化应激分析，从分子水平上阐述这些蛋白在恶性疟原虫HFn代谢中的功能，为揭示恶性疟原虫铁稳态代谢的分子机制提供科学依据，并为疟疾治疗新靶标的研究提供线索。

Malaria is a parasitic disease that seriously endangers human health. Red blood cells infected with Plasmodium falciparum are in a state of oxidative stress，and iron homeostasis is the key for parasite survival. However, neither ferritin nor ferritin receptors are found to be expressed in P. falciparum, and thus the mechanism of how P. falciparum stores and detoxifies the excess iron is unclear. Our preliminary studies demonstrate that P. falciparum can obtain H-ferritin (HFn) specifically. Immunofluorescence results indicate that the distribution of HFn in protozoa is same to that of the high-molecular mass rhoptry protein (RhopH), and the anti-RhopH2 antibodies inhibit the uptake of HFn, suggesting that RhopH regulate the H-ferritin metabolism of P. falciparum. In this project, the members of RhopH that interact with HFn will be verified by protein interaction analyses through the Cos-7 cell model and surface plasmon resonance (SPR) system; the membrane proteins with synergistic effects on RhopH will be screened by mass spectrometry and bioinformatics. Moreover, the role of these newly identified proteins and the underlying mechanism in HFn metabolism of P. falciparum will be defined by the protein localization, antibody inhibition assay and oxidative stress analysis. This project aims to elaborate the functions of these proteins in HFn metabolism of P. falciparum, which provided scientific basis for the molecular mechanism of iron homeostasis metabolism of P. falciparum, and provided clues for the research of new therapeutic targets for malaria.