Fosinopril analogs for the treatment of human babesiosis

巴贝斯虫病是一种在世界各地发现的类似疟疾的疾病，在美国流行。这种疾病是由 由巴贝斯虫属的红细胞内寄生虫引起。微小巴贝斯虫和邓肯巴贝斯虫，分别为 是美国报告的大多数病例的罪魁祸首，是通过肩部硬壳动物和人类传播的 白纹伊蚊分别经输血和输血传入。海流 人类巴贝斯虫病的治疗包括阿托瓦酮+阿奇霉素或 克林霉素+奎宁。然而，这些药物与高复发率、治疗失败有关。 和不良事件。此外，最近在感染微小杆菌的小鼠和体外感染邓肯杆菌的小鼠上的研究 表明这些寄生虫对这些药物具有天然的耐受性。这些限制强调了需要 治疗人类巴贝斯虫病的更有效和更安全的疗法。我们最近报道了 邓肯芽孢杆菌人红细胞体外连续培养体系的建立。使用这种分析方法， 我们筛选了FDA批准的药物库，并确定了福辛普利(二肽的前体药物 羧肽酶ACE抑制剂福辛普利拉)作为一种有效的抗巴贝斯菌抑制剂。该化合物也是 在小鼠巴贝斯虫病模型中，10 mg/kg对邓肯分枝杆菌和微小分枝杆菌有效。有趣的是， 福辛普利拉或其他ACE抑制剂均不影响邓肯分枝杆菌的体外生长。同样有趣的是， 福辛普利和Bortezomib(另一种有效的邓肯分枝杆菌抑制剂)的结构分析 化学筛选和已知的蛋白酶体抑制剂)显示了这两个化合物之间的相似之处。 总之，这些数据表明福辛普利的抗巴贝斯菌活性可能是由于抑制了 巴贝斯虫的ACE样肽酶和/或蛋白酶体活性。此应用程序的主要目标是 目的是鉴定福辛普利的类似物，这些类似物具有更强的抗巴贝斯体活性，但不具有ACE活性，并阐明 这些化合物对巴贝斯虫的作用机制。根据我们的初步数据，我们 提出以下三个具体目标。在目标1中，我们将确定前药形式是否 福辛普利是福辛普利的活性化合物，是福辛普利及其新合成类似物疗效的表征 体外抗登革分枝杆菌和微小分枝杆菌临床分离株和现场分离株并检测其结构活性 这些寄生虫特有的关系。在目标2中，我们将描述最具活性的药物的体内疗效 作为消除巴贝斯虫感染的一种策略，单用或与其他药物联合使用。在AIM 3.我们将进行生化、质谱学和遗传学分析，以阐明 以及巴贝斯虫对福辛普利及其类似物耐药的可能机制。建议的成功 三个目标将指导未来的临床试验，以创建治疗人类巴贝斯虫病的理想方案 没有复发。

Babesiosis is a malaria-like illness found worldwide and endemic in the United States. The disease is caused by intraerythrocytic parasites of the genus Babesia. Babesia microti and Babesia duncani, which are responsible for most cases reported in the United States, are transmitted to humans by Ixodes scapularis and Dermacentor albipictus ticks, respectively, and can also be introduced by blood transfusion. The current treatment for human babesiosis consists of combination therapies with atovaquone+azithromycin or clindamycin+quinine. However, these drugs are associated with high rate of recrudescence, treatment failures and adverse events. Furthermore, recent studies in mice infected with B. microti and in vitro with B. duncani showed that these parasites are naturally tolerant to these drugs. These limitations emphasize the need for more effective and safer therapies for treatment of human babesiosis. We have recently reported the development of a continuous in vitro culture system for B. duncani in human red blood cells. Using this assay, we screened a library of FDA-approved drugs and identified fosinopril (the prodrug of the dipeptidyl carboxypeptidase ACE inhibitor fosinoprilat) as a potent antibabesial inhibitor. The compound was also effective against both B. duncani and B. microti in mouse models of babesiosis at 10 mg/kg. Interestingly, neither fosinoprilat nor other ACE inhibitors affected the growth of B. duncani in vitro. Equally interesting, analysis of the structure of fosinopril and bortezomib (another potent inhibitor of B. duncani identified in the chemical screen and a known proteasome inhibitor) revealed similarities between the two compounds. Together these data suggest that the antibabesial activity of fosinopril could be due to inhibition of either an ACE-like peptidase and/or a proteasome activity of Babesia parasites. The primary goals of this application are to identify analogs of fosinopril with more potent antibabesial but no ACE activity, and to elucidate the mechanism of action of these compounds in Babesia parasites. Building upon our preliminary data, we propose the following three specific aims. In Aim 1, we will determine whether or not the prodrug form of fosinopril is the active compound, and characterize the efficacy of fosinopril and newly synthesized analogs against B. duncani and B. microti clinical and field isolates in vitro and examine the structure activity relationship specific to these parasites. In Aim 2, we will characterize the in vivo efficacy of the most active compounds alone or in combination with other drugs as a strategy for elimination of Babesia infections. In Aim 3, we will implement biochemical, mass spectrometry and genetic assays to elucidate the mode of action of and possible mechanisms of Babesia resistance to fosinopril and its analogs. The success of the proposed three aims will guide future clinical trials to create an ideal regimen for the treatment of human babesiosis with no recrudescence.