Lower SIRT1 activity may participate in COPD development by promoting senescence in different cell types of the lung tissue, as SIRT1 is also known to deacetylate p53 and negatively regulate the forkhead box O3 (FOXO3) pathway that is involved in the transcription of genes responsible for cellular senescence [127,128]. This evidence concerns the gene FOXO3 and chronic obstructive pulmonary disease.