The Schistosoma mansoni Cytochrome P450 (CYP3050A1) Is Essential for Worm Survival and Egg Development.
The Schistosoma mansoni Cytochrome P450 (CYP3050A1) Is Essential for Worm Survival and Egg Development.
复制标题
DOI：
10.1371/journal.pntd.0004279
复制
发表时间：
2015-12
影响因子：
3.8
通讯作者：
Williams DL
中科院分区：
文献类型：
--
作者：
Ziniel PD;Karumudi B;Barnard AH;Fisher EM;Thatcher GR;Podust LM;Williams DL
血吸虫病影响着发展中国家数百万人，每年造成20多万人死亡。由于替代品的毒性和活性范围有限，实际上只有一种药物--吡喹酮--可用于治疗。最近的数据表明，抗药性可能很快就会成为一个问题。因此，有必要确定新的药物靶点并开发治疗血吸虫病的药物。对曼氏血吸虫基因组序列中参与解毒过程的蛋白质进行分析发现，它编码一个细胞色素P450(CYP450)基因。在这里，我们报道了1452bp的开放阅读框架在其催化区域具有特征的血红素结合区，与半胱氨酸连接的保守的血红素，疏水前导序列作为膜相互作用区，并且总体结构保守。与人细胞色素P450的最高序列同源性为22%。在血吸虫幼虫中，双链RNA(DsRNA)沉默曼氏血吸虫(Sm)CYP450导致虫子死亡。用抗真菌的唑类细胞色素P450抑制剂处理幼虫或成虫，在低微摩尔浓度下会导致虫子死亡。此外，SmCYP450特异性dsRNA和咪康唑的组合显示出相加的血吸虫杀灭作用，支持SmCYP450是咪康唑靶标的假设。用咪康唑治疗发育中的曼氏血吸虫卵会导致胚胎发育的剂量依赖性停滞。我们的结果表明，SmCYP450对虫子的存活和卵的发育是必不可少的，并证实了它是一个新的药物靶点。初步的构效关系表明，咪康唑的1-(2，4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethan-1-ol部分是活性所必需的，合理的药物设计可以提高咪康唑的活性和选择性。在流行国家，有超过6亿人面临感染血吸虫病的风险，血吸虫病每年导致20多万人死亡，并使大多数感染者患上重大疾病。有人担心，由于抗药性蠕虫的进化，被广泛用于治疗血吸虫病的药物吡喹酮可能正在失去疗效。由于这种疾病主要影响发展中国家的穷人，制药公司对开发新药兴趣不大，目前没有一种药物正在接受测试。在本文中，我们主要关注一种新的寄生虫蛋白，细胞色素P450，我们建议将其作为一个新的药物靶点。蠕虫的不同寻常之处在于只有一个细胞色素P450基因；而人类有57个细胞色素P450基因。通过使用反向遗传和化学方法，我们发现血吸虫细胞色素P450是虫子存活和卵发育所必需的，因此是一个必要的和可用药的靶点。针对真菌细胞色素P450的药物已经用于治疗几种人类疾病，被确定为进一步开发血吸虫病治疗的潜在靶点。
Schistosomiasis affects millions of people in developing countries and is responsible for more than 200,000 deaths annually. Because of toxicity and limited spectrum of activity of alternatives, there is effectively only one drug, praziquantel, available for its treatment. Recent data suggest that drug resistance could soon be a problem. There is therefore the need to identify new drug targets and develop drugs for the treatment of schistosomiasis. Analysis of the Schistosoma mansoni genome sequence for proteins involved in detoxification processes found that it encodes a single cytochrome P450 (CYP450) gene. Here we report that the 1452 bp open reading frame has a characteristic heme-binding region in its catalytic domain with a conserved heme ligating cysteine, a hydrophobic leader sequence present as the membrane interacting region, and overall structural conservation. The highest sequence identity to human CYP450s is 22%. Double stranded RNA (dsRNA) silencing of S. mansoni (Sm)CYP450 in schistosomula results in worm death. Treating larval or adult worms with antifungal azole CYP450 inhibitors results in worm death at low micromolar concentrations. In addition, combinations of SmCYP450-specific dsRNA and miconazole show additive schistosomicidal effects supporting the hypothesis that SmCYP450 is the target of miconazole. Treatment of developing S. mansoni eggs with miconazole results in a dose dependent arrest in embryonic development. Our results indicate that SmCYP450 is essential for worm survival and egg development and validates it as a novel drug target. Preliminary structure-activity relationship suggests that the 1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethan-1-ol moiety of miconazole is necessary for activity and that miconazole activity and selectivity could be improved by rational drug design. Over 600 million people in endemic countries are at risk of contracting schistosomiasis, which results in over 200,000 deaths each year and significant illness to most people that are infected. There are concerns that the drug widely used for the treatment of schistosomiasis, praziquantel, may be losing efficacy due to evolution of drug resistant worms. Since the disease mainly affects the poor in developing countries, pharmaceutical companies have little interest in developing new drugs and none are currently being tested. In this paper we focus on a novel parasite protein, cytochrome P450, which we propose to be a new drug target. Worms are unusual in having only one cytochrome P450 gene; humans have 57 cytochrome P450 genes. By using reverse genetic and chemical approaches we found that the schistosome cytochrome P450 is essential for worm survival and egg development and, therefore, is an essential and druggable target. Drugs that target fungal cytochrome P450s and are already in use for treating several human diseases were identified as potential hits for further development for schistosomiasis treatment.