The role of metals in hypothiocyanite resistance in Escherichia coli.
The role of metals in hypothiocyanite resistance in Escherichia coli.
复制标题
金属在大肠杆菌抗次硫氰酸盐中的作用。
DOI：
10.1101/2024.03.07.583962
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发表时间：
2024
期刊：
影响因子：
--
通讯作者：
Gray,MichaelJ
中科院分区：
文献类型：
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作者：
Gray,MichaelJ
The innate immune system employs a variety of antimicrobial oxidants to control and kill host-associated bacteria. Hypothiocyanite/hypothiocyanous acid (−OSCN/HOSCN) is one such antimicrobial oxidant that is synthesized by lactoperoxidase, myeloperoxidase, and eosinophil peroxidase at sites throughout the human body. HOSCN has potent antibacterial activity while being largely non-toxic toward human cells. The molecular mechanisms by which bacteria sense and defend themselves against HOSCN have only recently begun to be elaborated, notably by the discovery of bacterial HOSCN reductase (RclA), an HOSCN-degrading enzyme widely conserved among bacteria that live on epithelial surfaces. In this paper, I show that Ni2+sensitizesEscherichia colito HOSCN by inhibiting glutathione reductase and that inorganic polyphosphate protectsE. coliagainst this effect, probably by chelating Ni2+ions. I also found that RclA is very sensitive to inhibition by Cu2+and Zn2+, metals that are accumulated to high levels by innate immune cells, and that, surprisingly, thioredoxin and thioredoxin reductase are not involved in HOSCN stress resistance inE. coli. These results advance our understanding of the contribution of different oxidative stress responses and redox buffering pathways to HOSCN resistance inE. coliand illustrate important interactions between metal ions and the enzymes bacteria use to defend themselves against oxidative stress.IMPORTANCEHypothiocyanite (HOSCN) is an antimicrobial oxidant produced by the innate immune system. The molecular mechanisms by which host-associated bacteria defend themselves against HOSCN have only recently begun to be understood. The results in this paper are significant because they show that the low molecular weight thiol glutathione and enzyme glutathione reductase are critical components of theEscherichia coliHOSCN response, working by a mechanism distinct from that of the HOSCN-specific defenses provided by the RclA, RclB, and RclC proteins and that metal ions (including nickel, copper, and zinc) may impact the ability of bacteria to resist HOSCN by inhibiting specific defensive enzymes (e.g., glutathione reductase or RclA).
