SIRT1 and pulmonary fibrosis: SIRT1 plays an important role in regulating alveolar epithelial cell 2 progenitor renewal and LF.609 Mechanistically, SIRT1 activation promotes self-renewal and differentiation of alveolar epithelial cell 2 in lung tissues of idiopathic pulmonary fibrosis (IPF) patients and aged mice.609 However, the opposite results have been reported for SIRT1 changes in LF.