5′-Nucleotidase is dispensable for the growth of Salmonella Typhimurium but inhibits the bactericidal activity of macrophage extracellular traps

• Published in: Archives of microbiology 2023-01, Vol.205 (1), p.20-20, Article 20
• Main Authors: Qian, Man, Xu, Ke, Zhang, Mengke, Niu, Junhui, Zhao, Tianxiang, Wang, Xiaoli, Jia, Yanyan, Li, Jing, Yu, Zuhua, He, Lei, Li, Yinju, Wu, Tingcai, Wei, Ying, Chen, Jian, Chen, Songbiao, Zhang, Chunjie, Liao, Chengshui
• Format: Article
• Language: English
• Subjects: Adenosine; Bactericidal activity; Biochemistry; Biomedical and Life Sciences; Biotechnology; Cell Biology; Degradation; Ecology; Environmental stress; Fluorescence microscopy; Gastroenteritis; Gene deletion; Immune response; Inflammation; Life Sciences; Macrophages; Magnesium; Microbial Ecology; Microbiology; Nuclease; Nucleotidase; Original Paper; Pathogens; Phosphates; Proteins; Salmonella; Zinc
• ISSN: 0302-8933; 1432-072X
• DOI: 10.1007/s00203-022-03353-3

Salmonella enterica serovar Typhimurium ( S. Typhimurium) is a zoonotic pathogen that causes severe gastroenteritis. The 5′-nucleotidases of pathogens can dephosphorylate adenosine phosphates, boost adenosine levels and suppress the pro-inflammatory immune response. In our previous study, an extracellular nuclease, 5′-nucleotidase, was identified in the extracellular proteins of S . Typhimurium. However, the nuclease activity and the function of the 5′-nucleotidase of S . Typhimurium have not been explored. In the present study, deletion of the 5 ′ -nucleotidase gene is dispensable for S . Typhimurium growth, even under environmental stress. Fluorescence microscopy revealed that the 5′-nucleotidase mutant induced more macrophage extracellular traps (METs) than the wild type did. Furthermore, recombinant 5′-nucleotidase protein (r5Nuc) could degrade λDNA, and the nuclease activity of r5Nuc was optimum at 37 °C and pH 6.0–7.0. The Mg 2+ enhanced the nuclease activity of r5Nuc, whereas Zn 2+ inhibited it. Meanwhile, deletion of the 5′-nucleotidase gene increased the bactericidal activity of METs, and r5Nuc could degrade METs and inhibit the bactericidal activity of METs. In conclusion, S. Typhimurium growth was independent of 5′-nucleotidase, but the nuclease activity of 5′-nucleotidase assisted S. Typhimurium to evade macrophage-mediated extracellular killing through degrading METs.