PLoS：中外学者高通量筛选结核病抑制剂

　　

生物通报道：来自美国西雅图生物医学研究所，中科院上海药物研究所等处的研究人员发表了题为“High-throughput Screening and Sensitized Bacteria Identify an M. tuberculosis Dihydrofolate Reductase Inhibitor with Whole Cell Activity”的文章，通过高通量筛选技术，报道了一种能够抑制结核分枝杆菌生长的化合物，相关成果公布在PLoS ONE杂志上。

文章的通讯作者分别为上海药物研究所，国家新药筛选中心主任王明伟研究员，以及西雅图生物医学研究所David R. Sherman，鉴于这项成果的重要性，卫生部部长陈竺向王明伟研究员发出了贺词。

结核病是一种古老的疾病，其致死病例可以追溯到公元前3世纪，而目前每年还有大约140万人死于结核病。结核分枝杆菌是结核病的病原体，常规化学药物治疗至少耗时6个月，且耐药现象日益严重。二氢叶酸还原酶催化产生的四氢叶酸是合成嘌呤和胸腺嘧啶的重要底物，抑制该酶的活性可以阻断DNA和RNA的合成，从而杀灭病原菌。

在这篇文章中，研究人员对结核分枝杆菌的二氢叶酸还原酶开展了高通量筛选和药效学评价，结果发现了一个特异性抑制剂。这一化合物能阻断二氢叶酸还原酶的活性，让结核分枝杆菌的DNA和RNA无法合成，从而抑制这种病菌的生长。这一成果，预示着一种新的治疗结核病药物有望问世，为全球结核病患者带去福音。

研究人员表示，这项项目是由中方科学家主导的国际合作，研究的结核病多发于发展中国家，属于“贫穷所致疾病”，因此，这种合作模式体现了中国科学家对全人类，特别是对发展中国家人民的责任。据悉，世卫组织将开展全球招标，让这一新发现的结核病抑制剂早日转化为良药。

这项研究得到了世界卫生组织、卫生部（“重大新药创制”国家重大科技专项）、科技部、中国科学院和诺和诺德公司的资助。

（生物通：万纹）

原文摘要：

High-throughput Screening and Sensitized Bacteria Identify an M. tuberculosis Dihydrofolate Reductase Inhibitor with Whole Cell Activity.

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, is a bacterial pathogen that claims roughly 1.4 million lives every year. Current drug regimens are inefficient at clearing infection, requiring at least 6 months of chemotherapy, and resistance to existing agents is rising. There is an urgent need for new drugs that are more effective and faster acting. The folate pathway has been successfully targeted in other pathogens and diseases, but has not yielded a lead drug against tuberculosis. We developed a high-throughput screening assay against Mtb dihydrofolate reductase (DHFR), a critical enzyme in the folate pathway, and screened a library consisting of 32,000 synthetic and natural product-derived compounds. One potent inhibitor containing a quinazoline ring was identified. This compound was active against the wild-type laboratory strain H37Rv (MIC99 = 207 µM). In addition, an Mtb strain with artificially lowered DHFR levels showed increased sensitivity to this compound (MIC99 = 70.7 µM), supporting that the inhibition was target-specific. Our results demonstrate the potential to identify Mtb DHFR inhibitors with activity against whole cells, and indicate the power of using a recombinant strain of Mtb expressing lower levels of DHFR to facilitate the discovery of antimycobacterial agents. With these new tools, we highlight the folate pathway as a potential target for new drugs to combat the tuberculosis epidemic.