Calcium Dependent Protein Kinase 1 as a drug target for T. gondii and C. parvum

描述（由申请人提供）： 需要新的治疗方法来治疗由隐孢子虫和刚地弓形虫引起的感染。钙依赖性蛋白激酶1（CDPK 1）是T.弓形虫被认为是弓形虫入侵过程中的关键。因此是弓形虫病的药物靶标。推测C.小孢子虫可能是隐孢子虫感染的关键。我们已经解决了TgCDPK 1和CpCDPK 1的晶体结构，并显示活性位点对不抑制哺乳动物激酶的“碰撞”激酶抑制剂（BKI）敏感。这种不同的敏感性是由于在哺乳动物蛋白激酶中存在的TgCDPK 1和CpCDPK 1的ATP结合位点中缺乏庞大的看门人侧链。因此，这些BKI相对于人激酶提供了抑制TgCDPK 1和CpCDPK 1的巨大选择性。此外，当在其他工作过程中给药时，BKI化合物在小鼠中显示出最小的毒性。我们的初步结果表明，基于已知支架的多种BKI化合物可以抑制TgCDPK 1和CpCDPK 1，也可以抑制T. gondii和C.在低-中等纳摩尔浓度下，微小细胞侵入。在T.弓形虫细胞导致对BKI效应的抗性，表明BKI通过CDPK 1抑制细胞进入。我们将开发口服生物可利用的、足够有效的、无毒的化合物，并治愈T。gondii和/或C.小的到本项目结束时，我们预计将确定和表征2至4个潜在的隐孢子虫病和弓形虫病的药物评价线索。该项目将开始开发新的药物，以治疗两种寄生原生动物隐孢子虫和弓形虫引起的疾病，这两种寄生原生动物通常通过食用不洁的食物或水传播。我们已经确定了一类化合物，可以特异性地抑制这些寄生虫用来入侵人类细胞的特定蛋白质。我们将设计和表征这类对人类无毒但有效治疗感染的化合物。 相关性：该项目将开始开发新的药物，以治疗由隐孢子虫和弓形虫这两种寄生原生动物引起的疾病，这两种寄生原生动物通常通过食用不纯的食物或水传播。我们已经确定了一类化合物，可以特异性地抑制这些寄生虫用来入侵人类细胞的特定蛋白质。我们将设计和表征这类对人类无毒但有效治疗感染的化合物。

DESCRIPTION (provided by applicant): New therapeutics are needed for infections caused by Cryptosporidium parvum and Toxoplasma gondii. Calcium dependent protein kinase 1 (CDPK1) of T. gondii is thought to be critical for the invasion process of T. gondii and thus is a drug target for toxoplasmosis. By inference, the homologous CDPK of C. parvum is likely to be critical for infection by cryptosporidium. We have solved the crystal structures of TgCDPK1 and CpCDPK1 and have shown the active sites are susceptible to "bumped" kinase inhibitors (BKI) that do not inhibit mammalian kinases. This differential sensitivity is due to the absence of a bulky gatekeeper side chain in the ATP binding site of both TgCDPK1 and CpCDPK1 that is present in mammalian protein kinases. Thus, these BKI offer tremendous selectivity for inhibition of TgCDPK1 & CpCDPK1 vs. human kinases. Furthermore, BKI compounds have shown minimal toxicity in mice when administered in the course of other work. Our preliminary results show that multiple BKI compounds based on a known scaffold can inhibit TgCDPK1 & CpCDPK1 and also inhibit T. gondii and C. parvum cell invasion at low-mid nanomolar concentrations. Expression of a mutant TgCDPK1 with a Met gatekeeper in T. gondii cells leads to resistance to the BKI effect, demonstrating the BKI inhibits cell entry via CDPK1. We will develop compounds that are orally bioavailable, sufficiently potent, lack toxicity, and cure animal models of T. gondii and/or C. parvum. By the end of this project we expect to identify and characterize 2 to 4 leads for evaluation as potential drugs for cryptosporidiosis and toxoplasmosis. This project will initiate development of new drugs to treat diseases caused by two parasitic protozoa, Cryptosporidium and Toxoplasma that are commonly transmitted by consumption of impure food or water. We have identified a class of chemical compounds that specifically inhibit a particular protein used by these parasites to invade human cells. We will design and characterize compounds of this class that are nontoxic to humans but effective in treating infection. Relevance: This project will initiate development of new drugs to treat diseases caused by two parasitic protozoa, Cryptosporidium and Toxoplasma, that are commonly transmitted by consumption of impure food or water. We have identified a class of chemical compounds that specifically inhibit a particular protein used by these parasites to invade human cells. We will design and characterize compounds of this class that are nontoxic to humans but effective in treating infection.