Fosinopril analogs for the treatment of human babesiosis

巴贝斯虫病是一种类似疟疾的疾病，在世界范围内发现，在美国流行。这种疾病是由 红细胞内寄生虫引起的巴贝氏田鼠和邓肯巴贝氏田鼠 造成美国报告的大多数病例，由肩突硬蜱传播给人类， 白纹革蜱分别也可通过输血传入。当前 用于人巴贝虫病的治疗包括阿托伐醌+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 和不良事件。此外，最近在感染B.用B.敦卡尼 表明这些寄生虫对这些药物具有天然耐受性。这些限制强调了以下需要： 用于治疗人类巴贝虫病的更有效和更安全的疗法。我们最近报道了 建立了B的体外连续培养体系。人体红细胞中的邓肯尼使用该测定， 我们筛选了FDA批准的药物库，并鉴定了福辛普利（二肽基的前体药物）， 羧肽酶ACE抑制剂福辛普利拉）作为有效的抗巴贝斯虫抑制剂。该化合物还 对B都有效。duncani和B.在10 mg/kg的巴贝斯虫病小鼠模型中的microti。有趣的是， 福辛普利拉和其他ACE抑制剂均不影响B的生长。Duncani in Vitro.同样有趣的是， 福辛普利和硼替佐米（另一种有效的B.邓肯尼在 化学筛选和已知的蛋白酶体抑制剂）揭示了两种化合物之间的相似性。 总之，这些数据表明福辛普利的抗巴贝斯虫活性可能是由于抑制 巴氏疟原虫的ACE样肽酶和/或蛋白酶体活性。此应用程序的主要目标 是为了鉴定具有更有效的抗巴贝斯虫活性但没有ACE活性的福辛普利类似物，并阐明 这些化合物在巴贝虫寄生虫中的作用机制。根据我们的初步数据，我们 提出以下三个具体目标。在目的1中，我们将确定化合物1的前药形式是否为 福辛普利是活性化合物，并表征福辛普利和新合成的类似物的功效 对抗B。duncani和B.对临床和田间分离物进行体外分离，并检测结构活性 与这些寄生虫的关系在目标2中，我们将表征最有效的药物组合物的体内功效。 本发明提供了单独或与其它药物组合的化合物作为消除巴氏杆菌感染的策略。在Aim中 3.我们会进行生化、质谱及基因化验，以阐明 以及巴贝妥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，以创造一种理想的治疗人类巴贝斯虫病的方案， 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.