Methylfolate Trap Promotes Bacterial Thymineless Death by Sulfa Drugs.
Methylfolate Trap Promotes Bacterial Thymineless Death by Sulfa Drugs.
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DOI：
10.1371/journal.ppat.1005949
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发表时间：
2016-10
期刊：
影响因子：
6.7
通讯作者：
Nguyen L
中科院分区：
文献类型：
--
作者：
Guzzo MB;Nguyen HT;Pham TH;Wyszczelska-Rokiel M;Jakubowski H;Wolff KA;Ogwang S;Timpona JL;Gogula S;Jacobs MR;Ruetz M;Kräutler B;Jacobsen DW;Zhang GF;Nguyen L
甲基叶酸陷阱是一种与贫血、神经管缺陷、阿尔茨海默氏痴呆症、心血管疾病和癌症相关的代谢障碍，于20世纪60年代被发现，将叶酸、维生素B12、蛋氨酸和同型半胱氨酸的代谢联系起来。然而，在从头合成叶酸的细菌中，这种现象的存在或生理意义一直是未知的。在这里，我们确定甲基叶酸陷阱作为一种新的决定因素的细菌内在死亡的磺胺类药物，抗生素，阻断从头叶酸合成。遗传诱变，化学互补，和代谢组学分析显示陷阱介导的代谢失衡，诱导胸腺嘧啶死亡，一种现象，其中快速生长的细胞屈服于胸腺嘧啶饥饿。限制B12的生物利用度，需要防止陷阱的形成，使用“抗维生素B12”分子，敏化细胞内细菌磺胺。由于可以在革兰氏阴性菌和分枝杆菌中通过甲基叶酸陷阱诱导来增强磺胺类药物的杀菌活性，因此它代表了使这些病原体对现有磺胺类药物更敏感的新策略。磺胺类药物是第一个成功治疗细菌感染的药物，但由于耐药微生物的出现，它们的使用后来下降。这些药物的恢复可以通过使耐药的分子机制失活来实现。化学基因组筛选首先确定了50个染色体位点，代表了耻垢分枝杆菌的全基因组抗叶酸剂耐药决定簇。有趣的是，许多决定因素与甲基叶酸陷阱的成分相似，甲基叶酸陷阱是一种仅在哺乳动物细胞中描述的代谢阻滞。靶向诱变，遗传和化学互补，然后通过化学分析建立了甲基叶酸陷阱作为磺胺敏感性的新机制，普遍存在于分枝杆菌和革兰氏阴性细菌病原体中。此外，代谢组学分析揭示了陷阱介导的叶酸和相关代谢途径的中断。这些代谢失衡诱导无胸腺嘧啶死亡，这是可逆的外源性胸腺嘧啶补充。化学限制维生素B12，一个重要的分子需要预防甲基叶酸陷阱，敏化细胞内细菌磺胺。因此，甲基叶酸陷阱的药物促进代表了一种新的叶酸拮抗策略，使病原菌更容易受到可用的，临床批准的磺胺类药物的影响。
The methylfolate trap, a metabolic blockage associated with anemia, neural tube defects, Alzheimer’s dementia, cardiovascular diseases, and cancer, was discovered in the 1960s, linking the metabolism of folate, vitamin B12, methionine and homocysteine. However, the existence or physiological significance of this phenomenon has been unknown in bacteria, which synthesize folate de novo. Here we identify the methylfolate trap as a novel determinant of the bacterial intrinsic death by sulfonamides, antibiotics that block de novo folate synthesis. Genetic mutagenesis, chemical complementation, and metabolomic profiling revealed trap-mediated metabolic imbalances, which induced thymineless death, a phenomenon in which rapidly growing cells succumb to thymine starvation. Restriction of B12 bioavailability, required for preventing trap formation, using an “antivitamin B12” molecule, sensitized intracellular bacteria to sulfonamides. Since boosting the bactericidal activity of sulfonamides through methylfolate trap induction can be achieved in Gram-negative bacteria and mycobacteria, it represents a novel strategy to render these pathogens more susceptible to existing sulfonamides. Sulfonamides were the first agents to successfully treat bacterial infections, but their use later declined due to the emergence of resistant organisms. Restoration of these drugs may be achieved through inactivation of molecular mechanisms responsible for resistance. A chemo-genomic screen first identified 50 chromosomal loci representing the whole-genome antifolate resistance determinants in Mycobacterium smegmatis. Interestingly, many determinants resembled components of the methylfolate trap, a metabolic blockage exclusively described in mammalian cells. Targeted mutagenesis, genetic and chemical complementation, followed by chemical analyses established the methylfolate trap as a novel mechanism of sulfonamide sensitivity, ubiquitously present in mycobacteria and Gram-negative bacterial pathogens. Furthermore, metabolomic analyses revealed trap-mediated interruptions in folate and related metabolic pathways. These metabolic imbalances induced thymineless death, which was reversible with exogenous thymine supplementation. Chemical restriction of vitamin B12, an important molecule required for prevention of the methylfolate trap, sensitized intracellular bacteria to sulfonamides. Thus, pharmaceutical promotion of the methylfolate trap represents a novel folate antagonistic strategy to render pathogenic bacteria more susceptible to available, clinically approved sulfonamides.
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