SIRT1 and triple-A syndrome: Moreover, calorie restriction, which is known to activate SirT1 (Guarente, 2013), prevents angII-induced AAA through SirT1-dependent deacetylation of H3 at lysine 9 on the MMP2 gene promoter, which downregulates MMP2 and subsequent elastin fragmentation in the aortic wall (Liu et al., 2016).