Bacterial-type hexokinase (HK) in the opportunistic parasite Cryptosporidium parv

描述：隐孢子虫是一种艾滋病-OI病原体和B类病原体。它是一种重要的水和食物传播的原生动物寄生虫，可导致人类和动物严重的水样腹泻。目前，只有一种药物（即，硝唑尼特[NTZ]）在美国被批准用于治疗免疫功能正常（但未免疫受损）患者的隐孢子虫病。然而，NTZ对隐孢子虫病不是100%有效。隐孢子虫也可能产生潜在的耐药性，类似于疟疾寄生虫和球虫的耐药性问题。因此，迫切需要开发新的抗隐孢子虫药物。我们这项转化研究的长期目标是表征C.糖酵解途径作为潜在的药物靶点。因为C.由于Parvum仅依赖糖酵解提供能量，我们假设负责糖酵解途径中反应进入步骤的细菌型CpHK可以作为该寄生虫中合理的药物靶标。为了验证这一假设，我们将进行实验以表征CpHK的生化特征，并通过化合物文库的HTS鉴定CpHK抑制剂用于未来的药物开发，表征最佳命中的抑制动力学，并测试其对C.小孢子体外生长。该探索性/开发性R21项目的主要目标是识别抑制CpHK和 为进一步研究HITS的抑制机制、构效关系、合成新的HITS类似物进行先导化合物的优化以及评价HITS和先导化合物在动物模型中抗隐孢子虫感染的效果提供了可靠的数据。

DESCRIPTION: Cryptosporidium parvum is an AIDS-OI pathogen and Category B agent. It is a significant water- and food-borne protozoan parasite that can cause severe watery diarrhea in humans and animals. Currently, only a single drug (i.e., nitazoxanide [NTZ]) is approved for treating cryptosporidiosis in immunocompetent (but not immunocompromized) patients in the United States. However, NTZ is not 100% effective against cryptosporidiosis. Potential drug resistance may also be developed in Cryptosporidium, similar to the drug resistance problem in malarial parasites and coccidia. Therefore, there is an urgent need to develop new anti-Cryptosporidium drugs. Our long-term goal of this translational research is to characterize the molecular and biochemical features of the essential enzymes in the C. parvum glycolytic pathway as potential drug targets. Because C. parvum relies solely on glycolysis for its energy, we hypothesize that the bacterial-type CpHK responsible for the entry step of reaction in the glycolytic pathways could serve as rational drug targets in this parasite. To test the hypothesis, we will perform experiments to characterize the biochemical features of CpHK and identify CpHK inhibitors for future drug development via HTS of compound libraries, characterize the inhibitory kinetics of top hits, and test their efficacies against C. parvum growth in vitro. The major goal of this exploratory/developmental R21 project is to identify hits that inhibit both CpHK enzyme activity and the parasite growth in vitro, which would produce conclusive data for further studying the mechanism of inhibition, structure-activity relationship, and to synthesize new analogs of hits for lead optimization, as well as to assess the efficacies of hits and leads agains cryptosporidial infection in animal models.