Chemotherapeutics Against Multi-Drug Resistant Tuberculosis

描述（由申请人提供）：耐多药结核病（MDR-TB）是一种新兴的传染性疾病威胁，被NIH列为C类优先病原体。目前，已经设计和合成了一系列化合物，它们是结核分枝杆菌（MTB）烯酰还原酶（InhA）的纳米摩尔抑制剂，InhA是结核药物发现的有效靶标。这些先导化合物抑制敏感和耐药结核分枝杆菌菌株的生长，具有相似的抗菌效力（1-2 ug/mL），这与不需要分枝杆菌KatG酶激活的化合物对异烟肼耐药临床菌株具有活性的假设一致。针对RFA-AI-05-019，本提案的目标是优化现有的先导化合物，使其可用于治疗耐药结核病患者的临床前试验。建议的研究包括以下具体目标。目的1：对现有先导化合物进行合理修饰，提高其体内外活性。提出的结构修改旨在(i)降低酶抑制的Ki， （ii）改善关键的体内参数，如溶解度和生物半衰期，以及（iii）提高对MTB细胞的渗透。目标2：将合成重点化合物文库，以(i)探索现有先导化合物周围的化学空间，（ii）生成具有不同化学支架的化合物，以扩大InhA抑制剂的化学多样性。目的3：测定目的1和目的2中化合物的体内和体外活性。初级筛选将包括IC50 （InhA）、MIC（敏感和耐多药结核菌株）和细胞毒性测量。在评估体内抗菌活性之前，二次筛选将提供毒性（MTD）和生物利用度估计。对其在活菌中的复合作用方式和酶抑制机制进行了评价。三级筛选将确定短期（GKO）和长期结核感染动物模型的抗菌活性。将对选定的化合物进行详细的药代动力学和药效学研究。Aim 3中筛选的信息将用于指导进一步化合物的合成。

DESCRIPTION (provided by applicant): Multi-drug resistant tuberculosis (MDR-TB) is an emerging infectious disease threat classified as a category C priority pathogen by NIH. Currently, a series of compounds have been designed and synthesized that are nanomolar inhibitors of the M. tuberculosis (MTB) enoyl reductase enzyme, InhA, a validated target for TB drug discovery. These lead compounds inhibit the growth of both sensitive and drug resistant MTB strains with similar antibacterial potency (1-2 ug/mL), consistent with the hypothesis that compounds that do not require activation by the mycobacterial KatG enzyme will be active against isoniazid-resistant clinical strains. In response to RFA-AI-05-019, the goal of this proposal is to optimize the existing lead compounds to the point at which they can be used in preclinical trials for the treatment of patients infected with drug resistant TB. The proposed research includes the following specific aims. Aim 1: The existing lead compounds will be rationally modified to improve their in vitro and in vivo activity. Proposed structural modifications are designed to (i) decrease in the Ki for enzyme inhibition, (ii) improve critical in vivo parameters such as solubility and biological half-life and (iii) improve penetration into MTB cells. Aim 2: Focused compound libraries will be synthesized to (i) explore chemical space around the existing lead compounds and (ii) generate compounds with different chemical scaffolds in order to expand the chemical diversity of the InhA inhibitors. Aim 3: The in vitro and in vivo activity of compounds from Aims 1 and 2 will be determined. Primary screens will involve IC50 (InhA), MIC (sensitive and MDR TB strains) and cytotoxicity measurements. Secondary screens will provide toxicity (MTD) and bioavailability estimates, prior to assessing in vivo antibacterial activity. The mode of compound action in live bacteria and the mechanism of enzyme inhibition will be assessed. Tertiary screens will determine antibacterial activity in short (GKO) and long term animal models of TB infection. Detailed pharmacokinetic and pharmacodynamic studies will be performed on select compounds. Information from the screens in Aim 3 will be used to direct the synthesis of further compounds.