Department of Biochemistry and Molecular Biology, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA.
Departments of Biochemistry and Chemistry, and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA.
Infect Immun. 2018 Jan 22;86(2). doi: 10.1128/IAI.00779-17. Print 2018 Feb.
The opportunistic fungal pathogen acquires essential metals from the host, yet the host can sequester these micronutrients through a process known as nutritional immunity. How the host withholds metals from has been poorly understood; here we examine the role of calprotectin (CP), a transition metal binding protein. When CP depletes bioavailable Zn from the extracellular environment, strongly upregulates and for Zn import and maintains constant intracellular Zn through numerous cell divisions. We show for the first time that CP can also sequester Cu by binding Cu(II) with subpicomolar affinity. CP blocks fungal acquisition of Cu from serum and induces a Cu starvation stress response involving and superoxide dismutases. These transcriptional changes are mirrored when invades kidneys in a mouse model of disseminated candidiasis, although the responses to Cu and Zn limitations are temporally distinct. The Cu response progresses throughout 72 h, while the Zn response is short-lived. Notably, these stress responses were attenuated in CP null mice, but only at initial stages of infection. Thus, Zn and Cu pools are dynamic at the host-pathogen interface and CP acts early in infection to restrict metal nutrients from .
机会性真菌病原体从宿主中获取必需的金属,但宿主可以通过营养免疫的过程将这些微量元素隔离起来。宿主如何限制的金属摄入一直知之甚少;在这里,我们研究了钙卫蛋白(CP)的作用,一种过渡金属结合蛋白。当 CP 从细胞外环境中耗尽生物可利用的 Zn 时,强烈地上调和以进行 Zn 摄取,并通过多次细胞分裂维持细胞内 Zn 的恒定。我们首次表明 CP 还可以通过与 Cu(II) 结合以亚皮摩尔亲和力来隔离 Cu。CP 阻止从血清中摄取 Cu,并诱导涉及和超氧化物歧化酶的 Cu 饥饿应激反应。当在播散性念珠菌病的小鼠模型中入侵肾脏时,会出现这些转录变化,尽管对 Cu 和 Zn 限制的反应在时间上是不同的。Cu 反应持续 72 小时,而 Zn 反应是短暂的。值得注意的是,这些应激反应在 CP 缺失小鼠中减弱,但仅在感染的初始阶段。因此,金属营养物质在宿主-病原体界面上是动态的,CP 在感染早期发挥作用,限制从进入。