Mycobacterial infection induces higher interleukin-1β and dysregulated lung inflammation in mice with defective leukocyte NADPH oxidase

PLoS One. 2017 Dec 11;12(12):e0189453. doi: 10.1371/journal.pone.0189453. eCollection 2017.

Abstract

Granulomatous inflammation causes severe tissue damage in mycobacterial infection while redox status was reported to be crucial in the granulomatous inflammation. Here, we used a NADPH oxidase 2 (NOX2)-deficient mice (Ncf1-/-) to investigate the role of leukocyte-produced reactive oxygen species (ROS) in mycobacterium-induced granulomatous inflammation. We found poorly controlled mycobacterial proliferation, significant body weight loss, and a high mortality rate after M. marinum infection in Ncf1-/- mice. Moreover, we noticed loose and neutrophilic granulomas and higher levels of interleukin (IL)-1β and neutrophil chemokines in Ncf1-/- mice when compared with those in wild type mice. The lack of ROS led to reduced production of IL-1β in macrophages, whereas neutrophil elastase (NE), an abundant product of neutrophils, may potentially exert increased inflammasome-independent protease activity and lead to higher IL-1β production. Moreover, we showed that the abundant NE and IL-1β were present in the caseous granulomatous inflammation of human TB infection. Importantly, blocking of IL-1β with either a specific antibody or a recombinant IL-1 receptor ameliorated the pulmonary inflammation. These findings revealed a novel role of ROS in the early pathogenesis of neutrophilic granulomatous inflammation and suggested a potential role of IL-1 blocking in the treatment of mycobacterial infection in the lung.

MeSH terms

  • Animals
  • Interleukin-1beta / metabolism*
  • Leukocytes / enzymology*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mycobacterium Infections / enzymology
  • Mycobacterium Infections / metabolism*
  • NADPH Oxidases / blood*
  • Pneumonia / metabolism*
  • Reactive Oxygen Species / metabolism

Substances

  • Interleukin-1beta
  • Reactive Oxygen Species
  • NADPH Oxidases

Grants and funding

This work was supported by the Taichung Veterans General Hospital Chiayi branch, Taiwan (RVHCY102005, RVHCY103005, RVHCY104005, RVHCY105005, and TCVGH-VHCY1068604) to WCC and research grants from Ministry of Science and Technology (MOST) to CCS. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.