ARYL BRANCHED CHAIN ACYL COA ESTERS INHIBIT MYCOBACTERIU

除异烟肼（INH）和乙硫异烟胺外，所有现有抗生素都通过抑制细菌RNA、DNA、蛋白质或细胞壁合成来抑制细菌生长。虽然细菌和哺乳动物细胞通过原理上相似的途径合成脂质，但催化细菌脂质合成的酶在基本方面与哺乳动物的对应物不同。细菌，尤其是M.结核病（M.tb.），含有哺乳动物细胞中没有的独特脂质。我们发现，已在人类中安全使用超过20年的降血脂药物吉非罗齐（GFZ）可阻断27种不同泛药物敏感和多重耐药结核分枝杆菌菌株的生长。以及其他10种细菌GFZ对L.嗜肺菌，无论是在细菌生长培养基和巨噬细胞。因此，在哺乳动物细胞中发现的代谢物不阻断GFZ对L.嗜肺菌我们筛选了>10（12）L。pneumophila菌落，但没有发现GFZ抗性突变体。这表明GFZ作用于高度保守、难以突变的酶。GFZ的3-和6-丙烯类似物在阻断14 C-乙酸掺入L中的效力是GFZ的5倍。嗜肺脂质。其他纤维酸，如氯贝特和苯扎贝特，是无效的。我们发现了一个L。利用GFZ的假定靶标嗜肺菌烯酰还原酶（Lpn FabX）纯化了该酶，并显示其被GFZ的CoA加合物（GFZ-CoA）竞争性抑制，但不被GFZ抑制。GFZ-CoA还竞争性抑制InhA、M. tb.烯酰还原酶是INH的靶点。L.嗜肺菌在体内将3 H-GFZ转化为3 H-GFZ-CoA。GFZ-CoA是第一个被鉴定的细菌烯酰还原酶的竞争性抑制剂。要求提供资金，以探索GFZ抑制结核分枝杆菌生长的机制，并测试GFZ及其3-和6-丙烯类似物单独使用和与其他抗结核药物联合使用对巨噬细胞和小鼠中结核分枝杆菌生长的影响。

All current antibiotics, with the exception of isoniazid (INH) and ethionamide, inhibit bacterial growth by inhibiting bacterial RNA, DNA, protein or cell wall synthesis. While bacteria and mammalian cells synthesize lipids via pathways that are similar in principle, the enzymes that catalyze bacterial lipid synthesis differ in fundamental respects from their mammalian counterparts. Bacteria, especially M. tuberculosis (M.tb.), contain unique lipids not found in mammalian cells. We have discovered that the lypolipidemic drug gemfibrozil (GFZ), which has been used safely in humans for >20 years, blocks growth of 27 different pan-drug sensitive and multi-drug resistant strains of M tb. as well as 10 other species of bacteria. GFZ exerts a bactericidal effect on L. pneumophila, both in bacterial growth medium and in macrophages. Thus metabolites found in mammalian cells do not block GFZ's inhibitory effect on L. pneumophila. We have screened >10(12) L. pneumophila colonies but have found no GFZ-resistant mutants. This suggests that GFZ acts on highly conserved, hard to mutate enzyme(s). The 3- and 6-propylene analog of GFZ are 5- fold more potent than GFZ in blocking 14C-acetate incorporation into L. pneumophila lipids. Other fibric acids such as clofibrate and bezafibrate, are ineffective. We have identified an L. pneumophila enoyl reductase (Lpn FabX) that is GFZ's presumptive target, purified the enzyme and showed it is competitively inhibited by GFZ's CoA adduct (GFZ-CoA), but not by GFZ. GFZ-CoA also competitively inhibits InhA, the M.tb. enoyl reductase that is a target of INH. L. pneumophila converts 3H-GFZ to 3H- GFZ-CoA in vivo. GFZ-CoA is the first competitive inhibitor of a bacterial enoyl reductase to be identified. Funds are requested to explore the mechanisms by which GFZ inhibits M.tb growth, and to test the effects of GFZ and of its 3- and 6-propylene analogs, alone and in combination with other anti-tuberculosis drugs, on M.tb growth in macrophages and in mice.