Severe refractory asthma is characterised by neutrophil-dominated lung inflammation. Neutrophils’ capacity to produce reactive oxygen species (ROS) via enzyme NADPH oxidase Nox2 is unmet by other immune cells. Neutrophil Nox2 represents the main source of superoxide during respiratory virus infection (Figure A). ROS play an important role in the pathogenesis of asthma. Antioxidant treatments have been shown to ameliorate pathology. However, their effectiveness is limited. ROS beyond acting as damaging radicals, function as important intracellular and/or extracellular mediators (Figure B), with detrimental and beneficial roles by suppressing inflammation or inducing repair processes. Therefore, antioxidant therapies require selective strategies, inhibiting specific ROS sources or preserving, even elevating certain oxygen metabolites.
Aims:
1. Investigate the role of neutrophil-derived ROS in severe asthma.
2. Identify immunomodulatory neutrophil Nox2-controlled Redox-signalling in neutrophilic airway inflammation.
3. Address if targeted inhibition or elevation of specific ROS sources ameliorates pathology.
Experimental Approach:
This investigation will use concomitant exposure of mice to aeroallergens and endotoxin to induce neutrophilic inflammation in a novel neutrophil-specific Nox2-deficient mouse model as well as airway epithelial cell cultures grown at air-liquid interface.
1. Phenotype mouse model using flow cytometry and microscopy in combination with fluorescent ROS probes, gene and protein expression analysis.
2. Analyse molecular mechanisms of ROS-mediated immune modulation.
3. Find and verify targets of oxidation in affected inflammatory pathways.
The student will be trained in lung inflammation and respiratory diseases, will use in vitro and in vivo models, and learn techniques associated with cell culture, flow cytometry, microscopy and mass spectrometry.
