Generation of novel HCV drugs through engineereing of the cssA gene

描述（由申请人提供）：HCV感染是一个普遍和日益严重的健康问题。据估计，多达2%的美国人口和2.5%的世界人口被HCV感染。目前仅在美国每年就有15，000人死于该病，预计到2010年这一数字将增加三倍。HCV感染患者的治疗选择非常有限，目前可用的治疗方法中没有一种能够消除患者感染的可能性超过50%。因此，对于用于治疗HCV感染的新的和更好的药物存在显著的且立即未满足的医学需求。环肽是一类对人类健康有重要贡献的化合物。这些化合物在从感染性疾病到癌症甚至自身免疫性疾病的几个治疗领域中具有相当大的存在。50年前免疫调节环肽环孢素A（CsA）的发现产生了真正深远的影响，并真正开创了现代移植医学的时代。虽然环肽通常是非常有效的药物，但它们也是复杂的天然产物分子（从细菌和真菌中分离），因此，用常规的基于合成化学的方法合成和/或修饰它们是困难和昂贵的。因此，目前使用的基于环肽的药物是天然化合物或具有微小修饰的天然化合物。这些化合物中的绝大多数尚未针对人类使用进行优化，因此，尚未探索环肽作为人类治疗剂的全部潜力。本提案中概述的项目的总体目标是使用一种新的基因工程方法，该方法允许具有成本效益的生成和生产修饰的和新的环肽，以生成新的和改进的抗HCV候选药物。已建立的免疫调节药物CsA，具有广泛的药理活性，包括抗HCV活性的化合物，将被用作工程模板。该项目涉及开发方法和一套遗传工具，允许通过在生产生物Tolypocladium inflatum中设计负责其合成的非核糖体肽合成酶（NRPS）复合物，对天然CsA的结构进行修饰。预期的基因工程方法的成功实施将不仅允许制备预期的新型抗HCV候选药物，而且允许制备用于其他治疗应用的化合物，例如抗真菌和抗寄生虫化合物，甚至可能保留天然CsA的优异免疫调节性质但不具有肾毒性的衍生物。公共卫生相关性：丙型肝炎病毒（HCV）是一个重要的和迅速增长的全球性健康问题。HCV感染与相当大的发病率和死亡率相关，现有的治疗方法从感染患者中消除病毒的可能性不超过50%。拟议项目的主要目的是使用一种新的基因工程方法来开发新的、有效的和耐受性良好的治疗丙型肝炎病毒感染的药物。

DESCRIPTION (provided by applicant): HCV infections are a prevalent and growing health problem. It is estimated that as many as 2% of the US population, and 2.5% of the population world-wide, are infected by HCV. The disease currently causes 15,000 deaths/year in US alone, a number that is predicted to increase three-fold by 2010. Treatment options for HCV infected patients are quite limited, and none of the currently available treatments has a better than 50% probability of eliminating the infection from the patient. Consequently, there is a significant, and immediate unmet medial need for new and better drugs for the treatment of HCV infections. The cyclic peptides constitute a class of compounds that have made crucial contributions human health. These compounds have a considerable presence in several therapeutic areas, ranging from infectious diseases, to cancer and even autoimmune disorders. The discovery of the immunomodulatory cyclic peptide Cyclosporin A (CsA) 50 years ago had a truly profound impact and literally ushered in the era of modern transplantation medicine. Although cyclic peptides often are very efficient drugs, they are also complex natural product molecules (isolated from bacteria and fungi) and as such, they are difficult and expensive to synthesize and/or modify with conventional, synthetic chemistry-based methodologies. Consequently, currently used cyclic peptide-based drugs are either native compounds or native compounds with minor modifications. The vast majority of these compounds have not been optimized for human use and, consequently, the full potential of cyclic peptides, as human therapeutics, has not been explored. The overall goal of the project outlined in this proposal is to use a novel genetic engineering approach that allows cost-effective generation and production of both modified and new cyclic peptides, to generate new and improved anti-HCV drug candidates. The established immunomodulatory drug CsA, a compound with a wide range of pharmacological activities that includes anti-HCV activity, will be used as engineering template. The project involves development of methodologies and a set of genetic tools that allows introduction of modifications to the structure of native CsA by engineering the non-ribosomal peptide synthetase (NRPS) complex responsible its synthesis, in the producer organism Tolypocladium inflatum. Successful implementation of the envisioned genetic engineering approach will not only allow preparation of the envisioned novel anti-HCV drug candidate(s), but also compounds for other therapeutic applications, such as antifungal and antiparasitical compounds and perhaps even derivatives that retain the excellent immunomodulatory properties of native CsA, but not the nephrotoxicity. PUBLIC HEALTH RELEVANCE: Hepatitis C virus (HCV) constitutes a significant and rapidly growing health problem world-wide. HCV infections are associated with considerable morbitity and mortality and existing therapies allows no more than a 50% probability of eliminating the virus form an infected patient. The principal aim of the proposed project is to use a novel genetic engineering approach to develop new, efficacious and well-tolerated drugs for the treatment of HCV infections.