Open AccessThe role of reactive oxygen intermediates in the intracellular fate of Leptospira interrogans in the macrophages of different hosts
Author(s) -
Shijun Li,
Peili Li,
Lei Zhang,
WeiLin Hu,
Ming Wang,
Ying Li,
Guangpeng Tang,
Dingming Wang,
Biao Zhou,
Jie Yan
Publication year - 2017
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0178618
Subject(s) - apocynin , intracellular , leptospira interrogans , nadph oxidase , microbiology and biotechnology , intracellular parasite , reactive oxygen species , superoxide , macrophage , phagosome , biology , leptospira , chemistry , biochemistry , in vitro , enzyme , serotype
Background Pathogenic species of Leptospira cause leptospirosis, a global zoonotic disease. Our previous work showed that leptospires survive and replicate in human macrophages but are killed in murine macrophages. However, the mechanism responsible for the different intracellular fates of leptospires within the macrophages of different hosts remains unclear. Results The present study demonstrates that infection with Leptospira interrogans caused significant up-regulation of reactive oxygen species (ROS) and superoxide in J774A.1 cells but did so to a lesser extent in THP-1 cells. The up-regulation of ROS and superoxide was significantly inhibited by the NADPH oxidase inhibitor apocynin. The damaged leptospires and remnants of leptospires within membrane-bound vacuoles were significantly inhibited by apocynin in J774A.1 cells but were less inhibited in THP-1 cells. In addition, apocynin significantly prevented damage to leptospires and the co-localization of L . interrogans with lysosomes in J774A.1 cells but did so to a lesser extent in THP-1 cells. Furthermore, the relative fluorescence intensity levels of intracellular leptospires and the viability of the intracellular leptospires increased in apocynin pretreated J774A.1 and THP-1 cells after 2 h of infection. Conclusions The present study, based on our previous findings, further demonstrated that ROS contributed substantially to the bactericidal ability of mouse macrophages to kill intracellular leptospires. However, ROS did not contribute as much in human macrophages, which partially explains the different intracellular fates of L . interrogans in human and mouse macrophages.