Generation of novel HCV drugs through engineereing of the cssA gene

描述（由申请人提供）：HCV感染是一种普遍且日益严重的健康问题。据估计，多达2%的美国人口和2.5%的全球人口感染了HCV。目前，仅在美国，每年就有1.5万人死于该疾病，预计到2010年，这一数字将增加三倍。HCV感染患者的治疗选择相当有限，目前可用的治疗方法中，没有一种消除患者感染的概率超过50%。因此，对于治疗丙型肝炎病毒感染的新药和更好的药物，存在着重大的、尚未得到满足的迫切医疗需求。环肽是一类对人类健康有重要贡献的化合物。这些化合物在一些治疗领域有相当大的存在，从传染病到癌症，甚至自身免疫性疾病。50年前，免疫调节环孢素A （Cyclosporin A, CsA）的发现产生了真正深远的影响，并真正开启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出来），因此，用传统的合成化学方法合成和/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要么是天然化合物，要么是经过微小修饰的天然化合物。这些化合物中的绝大多数还没有被优化用于人类，因此，环肽作为人类治疗药物的全部潜力还没有被探索出来。该项目的总体目标是使用一种新的基因工程方法，使改性和新环肽的生产具有成本效益，以产生新的和改进的抗hcv候选药物。已建立的免疫调节药物CsA是一种具有广泛药理活性的化合物，包括抗hcv活性，将被用作工程模板。该项目涉及开发方法和一套遗传工具，这些工具可以通过设计生产生物体中负责其合成的非核糖体肽合成酶（NRPS）复合物，对天然CsA的结构进行修改。设想的基因工程方法的成功实施不仅将允许制备设想的新型抗hcv候选药物，而且还可以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优异的免疫调节特性的衍生物，但不具有肾毒性。公共卫生相关性：丙型肝炎病毒（HCV）在世界范围内构成了一个重大且迅速增长的健康问题。丙型肝炎病毒感染与相当高的发病率和死亡率相关，现有治疗方法允许不超过50%的概率从感染患者中消除病毒。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药物来治疗丙型肝炎病毒感染。

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.