Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA.
Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia.
Infect Immun. 2018 Dec 19;87(1). doi: 10.1128/IAI.00642-18. Print 2019 Jan.
During infection, the host utilizes a diverse array of processes to combat invaders, including the restriction of availability of essential nutrients such as manganese. Similarly to many other pathogens, possesses two manganese importers, MntH and MntABC. Several infection models have revealed a critical role for MntABC during staphylococcal infection. However, culture-based studies have suggested parity between the two transporters when cells are resisting manganese starvation imposed by the manganese binding immune effector calprotectin. In this investigation, initial elemental analysis revealed that MntABC is the primary transporter responsible for obtaining manganese in culture in the presence of calprotectin. MntABC was also necessary to maintain wild-type levels of manganese-dependent superoxide dismutase activity in the presence of calprotectin. Building on this framework, we investigated if MntABC enabled to resist the synergistic actions of nutritional immunity and other host defenses. This analysis revealed that MntABC critically contributes to staphylococcal growth when is subjected to manganese limitations and exposed to oxidative stress. This transporter was also important for growth in manganese-limited environments when was forced to consume glucose as an energy source, which occurs when it encounters nitric oxide. MntABC also expanded the pH range conducive for growth under conditions of manganese scarcity. Collectively, the data presented in this work provide a robust molecular basis for the crucial role of MntABC in staphylococcal virulence. Further, this work highlights the importance of synergy between host defenses and the necessity of evaluating the contribution of virulence factors to pathogenesis in the presence of multiple stressors.
在感染过程中,宿主利用多种过程来对抗入侵者,包括限制锰等必需营养物质的可用性。与许多其他病原体一样, 拥有两种锰转运蛋白, MntH 和 MntABC。几种感染模型表明, MntABC 在葡萄球菌感染中起着关键作用。然而,基于培养的研究表明,当细胞抵抗由锰结合免疫效应物钙卫蛋白引起的锰饥饿时,两种转运蛋白之间存在平等性。在这项研究中,最初的元素分析表明, MntABC 是在钙卫蛋白存在的情况下在培养物中获取锰的主要转运蛋白。在钙卫蛋白存在的情况下, MntABC 对于维持锰依赖性超氧化物歧化酶活性的野生型水平也是必需的。在此基础上,我们研究了 MntABC 是否使 能够抵抗营养免疫和其他宿主防御的协同作用。该分析表明,当 受到锰限制并暴露于氧化应激时, MntABC 对葡萄球菌的生长至关重要。当 被迫消耗葡萄糖作为能源时,即在遇到一氧化氮时,该转运蛋白对于在锰限制环境中的生长也很重要。 MntABC 还扩大了在锰匮乏条件下有利于 生长的 pH 范围。总的来说,本工作提供了 MntABC 在葡萄球菌毒力中关键作用的强大分子基础。此外,这项工作强调了宿主防御之间协同作用的重要性,以及在存在多种胁迫时评估毒力因子对发病机制的贡献的必要性。