SIRT1 and chronic obstructive pulmonary disease: For example, in pulmonary diseases such as COPD, oxidative stress, and, in particular, augmented H2O2 concentration via phosphoinositide-3-kinase (PI3K) signaling, increases miR-34a levels, with the consequent reduction in both mRNA and the amounts of sirtuin-1 and -6 (SIRT1/-6) deacetylases.