Manganese Detoxification by MntE Is Critical for Resistance to Oxidative Stress and Virulence of Staphylococcus aureus
Manganese Detoxification by MntE Is Critical for Resistance to Oxidative Stress and Virulence of Staphylococcus aureus
复制标题
DOI：
10.1128/mbio.02915-18
复制
发表时间：
2019-01-01
期刊：
影响因子：
6.4
通讯作者：
Skaar, Eric P.
中科院分区：
文献类型：
--
作者：
Grunenwald, Caroline M.;Choby, Jacob E.;Skaar, Eric P.
锰（Mn）是金黄色葡萄球菌（Staphylococcus aureus）的致病关键的必需微量营养素，金黄色葡萄球菌是人类发病和死亡的重要原因。特别地，过量的Mn是有毒的;因此，维持细胞内Mn稳态是生存所必需的。在这里，我们描述了一个锰出口商在S。金黄色葡萄球菌，MntE，其是阳离子扩散促进剂（CDF）蛋白家族的成员并且在革兰氏阳性病原体中保守。响应于过量Mn的mntE转录的上调依赖于MntR的存在，MntR是mntABC Mn摄取系统的转录阻遏物。mntE或mntR的失活导致补充有Mn的培养基中的生长减少，证明MntE是过量Mn的解毒所需的。mntE的失活导致细胞内Mn水平升高，但细胞内铁（Fe）水平降低，支持MntE作为Mn外排泵发挥作用且Mn外排影响Fe稳态的假设。mntE失活的菌株对氧化剂NaOCl和百草枯更敏感，表明Mn稳态对于抵抗氧化胁迫至关重要。此外，mntE和mntR是S.金黄色葡萄球菌感染，提示S.金黄色葡萄球菌在体内经历Mn毒性。综合起来，这些数据支持MntR通过平衡mntABC的转录抑制和mntE的诱导来控制Mn稳态的模型，这两者对于S.金黄色葡萄球菌致病性。因此，Mn流出有助于细菌在感染期间的存活和毒力，确立MntE作为潜在的抗微生物靶点，并扩展我们对Mn体内平衡的理解。重要性锰（Mn）通常被视为对病原菌有益的关键营养素，这是由于其作为酶辅助因子的功能和其作为抗氧化剂的能力;然而矛盾的是，高浓度的这种过渡金属可能是有毒的。在这项工作中，我们证明了金黄色葡萄球菌利用阳离子扩散促进剂（CDF）家族蛋白MntE，以减轻锰毒性通过流出过量的锰。mntE的失活导致S.金黄色葡萄球菌抗氧化应激和S.金黄色葡萄球菌介导的全身感染小鼠模型中的死亡率。这些结果突出了MntE介导的Mn解毒在细胞内Mn稳态、抗氧化应激和S.金黄色葡萄球菌毒力。因此，这确立了MntE作为抗S开发的潜在靶标。金黄色葡萄球菌治疗学
Manganese (Mn) is an essential micronutrient critical for the pathogenesis of Staphylococcus aureus, a significant cause of human morbidity and mortality. Paradoxically, excess Mn is toxic; therefore, maintenance of intracellular Mn homeostasis is required for survival. Here we describe a Mn exporter in S. aureus, MntE, which is a member of the cation diffusion facilitator (CDF) protein family and conserved among Gram-positive pathogens. Upregulation of mntE transcription in response to excess Mn is dependent on the presence of MntR, a transcriptional repressor of the mntABC Mn uptake system. Inactivation of mntE or mntR leads to reduced growth in media supplemented with Mn, demonstrating MntE is required for detoxification of excess Mn. Inactivation of mntE results in elevated levels of intracellular Mn, but reduced intracellular iron (Fe) levels, supporting the hypothesis that MntE functions as a Mn efflux pump and Mn efflux influences Fe homeostasis. Strains inactivated for mntE are more sensitive to the oxidants NaOCl and paraquat, indicating Mn homeostasis is critical for resisting oxidative stress. Furthermore, mntE and mntR are required for full virulence of S. aureus during infection, suggesting S. aureus experiences Mn toxicity in vivo. Combined, these data support a model in which MntR controls Mn homeostasis by balancing transcriptional repression of mntABC and induction of mntE, both of which are critical for S. aureus pathogenesis. Thus, Mn efflux contributes to bacterial survival and virulence during infection, establishing MntE as a potential antimicrobial target and expanding our understanding of Mn homeostasis.IMPORTANCE Manganese (Mn) is generally viewed as a critical nutrient that is beneficial to pathogenic bacteria due to its function as an enzymatic cofactor and its capability of acting as an antioxidant; yet paradoxically, high concentrations of this transition metal can be toxic. In this work, we demonstrate Staphylococcus aureus utilizes the cation diffusion facilitator (CDF) family protein MntE to alleviate Mn toxicity through efflux of excess Mn. Inactivation of mntE leads to a significant reduction in S. aureus resistance to oxidative stress and S. aureus-mediated mortality within a mouse model of systemic infection. These results highlight the importance of MntE-mediated Mn detoxification in intracellular Mn homeostasis, resistance to oxidative stress, and S. aureus virulence. Therefore, this establishes MntE as a potential target for development of anti-S. aureus therapeutics.