Chronic obstructive pulmonary disease (
COPD) is a respiratory disorder caused by extended exposure of the airways to noxious stimuli, principally cigarette
smoke (CS). The mechanisms through which
COPD develops are not fully understood, though it is believed that the disease process includes a genetic component, as not all smokers develop
COPD. To investigate the mechanisms that lead to the development of
COPD/
emphysema, we measured whole genome gene expression and several
COPD-relevant biological endpoints in mouse lung tissue after exposure to two CS doses for various lengths of time. A novel and powerful method, Reverse Engineering and Forward Simulation (REFS™), was employed to identify key molecular drivers by integrating the gene expression data and four measured
COPD-relevant endpoints (
matrix metalloproteinase (
MMP) activity,
MMP-9 levels,
tissue inhibitor of metalloproteinase-1 levels and lung weight). An ensemble of molecular networks was generated using REFS™, and simulations showed that it could successfully recover the measured experimental data for gene expression and
COPD-relevant endpoints. The ensemble of networks was then employed to simulate thousands of in silico gene knockdown experiments. Thirty-three molecular key drivers for the above four
COPD-relevant endpoints were therefore identified, with the majority shown to be enriched in
inflammation and
COPD.