Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA.
Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA.
Discov Med. 2020 Jan-Feb;29(156):65-77.
Staphylococcus aureus can cause both acute and recurrent persistent infections such as peritonitis, endocarditis, abscesses, osteomyelitis, and chronic wound infections. Effective therapies to treat persistent disease are paramount. However, the mechanisms of S. aureus persistence are poorly understood. In this study, we performed a comprehensive and unbiased high-throughput mutant screen against a transposon-insertion mutant library of S. aureus USA300 and focused on the role of argJ encoding an acetyltransferase in the arginine biosynthesis pathway, whose transposon insertion caused a significant defect in persister formation using multiple drugs and stresses. Genetic complementation and arginine supplementation restored persistence in the argJ transposon insertion mutant while generation of mutations on the active site of the ArgJ protein caused a defect in persistence. Quantitative RT-PCR analysis showed that the genes encoded in the arg operon were over-expressed under drug stressed conditions and in stationary phase cultures. In addition, the argJ mutant had attenuated virulence in both mouse and C. elegans. Our studies identify a new mechanism of persistence mediated by arginine metabolism in S. aureus. These findings provide not only novel insights about the mechanisms of S. aureus persistence but also offer novel therapeutic targets that may help to develop more effective treatment of persistent S. aureus infections.
金黄色葡萄球菌可引起急性和复发性持续性感染，如腹膜炎、心内膜炎、脓肿、骨髓炎和慢性伤口感染。有效的治疗持续性疾病至关重要。然而，金黄色葡萄球菌持续存在的机制尚未完全了解。在这项研究中，我们对金黄色葡萄球菌 USA300 的转座子插入突变文库进行了全面且无偏的高通量突变筛选，并重点研究了编码乙酰转移酶的 argJ 在精氨酸生物合成途径中的作用，该基因的转座子插入导致使用多种药物和应激时，在形成持久性方面存在显著缺陷。遗传互补和精氨酸补充恢复了 argJ 转座子插入突变体的持久性，而 ArgJ 蛋白活性位点的突变则导致持久性缺陷。定量 RT-PCR 分析表明，在药物应激条件下和静止期培养物中，arg 操纵子编码的基因表达过度。此外，argJ 突变体在小鼠和秀丽隐杆线虫中的毒力减弱。我们的研究确定了金黄色葡萄球菌中由精氨酸代谢介导的新的持久性机制。这些发现不仅为金黄色葡萄球菌持久性的机制提供了新的见解，还为开发更有效的治疗持续性金黄色葡萄球菌感染提供了新的治疗靶点。
