Negative reciprocal regulation between SIRT1 and Per2 in circadian clock during aging (ChIP-Seq)

SIRT1 is involved in both aging and circadian clock regulation, yet the link between the two processes in relation to SIRT1 function is unclear. Analyzing SIRT1-deficient cells and mice, we demonstrated that SIRT1 and Per2 constitute a reciprocal negative regulation loop that plays important roles in modulating circadian rhythmicity, metabolism and aging. SIRT1-deficient mice exhibit profound premature aging and enhanced H4K16 acetylation in the promoter of Per2 leading to its overexpression; in turn, Per2 suppresses SIRT1 transcription through binding to SIRT1 promoter at the CLOCK/BMAL1 site. We further demonstrated that absence of SIRT1 or ectopic overexpression of Per2 in the liver resulted in an accelerated pace of circadian rhythm and dysregulated amplitude, mimicking the natural process of circadian shortening in aged mice. Thus the interplay between SIRT1 and Per2 provides a link between the life-long sequence of aging and circadian clock maintenance.