In respiratory diseases such as chronic obstructive pulmonary disease (COPD), smokers had elevated ATP concentrations in bronchoalveolar lavage fluid (BALF), which potentiated the response of airway macrophages to promote secretion of pro-inflammatory and tissue-degrading mediators such as MMP9 Mitochondrial metabolites have also been described as important modulators of inflammatory pathways in innate immune cells (i.e. dendritic cells and macrophages)[37]. The gene discussed is MMP9; the disease is chronic obstructive pulmonary disease.