title: Light-dark condition regulates sirtuin mRNA levels in the retina.
abstract: Sirtuins (Sirt1-7) are nicotinamide adenine dinucleotide (NAD)-dependent protein deacetylases/ADP-ribosyltransferases that modulate many metabolic responses affecting aging. Sirtuins expressed in tissues and organs involved in systemic metabolism have been extensively studied. However, the characteristics of sirtuins in the retina, where local energy expenditure changes dynamically in response to light stimuli, are largely unknown. Here we analyzed sirtuin mRNA levels by real-time PCR, and found that all seven sirtuins are highly expressed in the retina compared with other tissues, such as liver. We then analyzed the sirtuin mRNA profiles in the retina over time, under a 12-h light/12-h dark cycle (LD condition) and in constant darkness (DD condition). All seven sirtuins showed significant daily variation under the LD condition, with all except Sirt6 being increased in the dark phase. The expression patterns were different under the DD condition, suggesting that sirtuin mRNA levels except Sirt6 are affected by light-dark condition. These findings were not obtained in the brain and liver. In addition, the mRNA expression patterns of Nicotinamide phosphoribosyltransferase (Nampt), peroxisome proliferator-activated receptor gamma coactivator (PGC1α), and transcription factor A, mitochondrial (Tfam) in the retina, were similar to those of the sirtuins except Sirt6. Our observations provide new insights into the metabolic mechanisms of the retina and the sirtuins' regulatory systems.
authors: Laboratory of Retinal Cell Biology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan; Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan.
authors: Norimitsu
authors: N
authors: Ban
authors: Yoko
authors: Y
authors: Ozawa
authors: Takaaki
authors: T
authors: Inaba
authors: Seiji
authors: S
authors: Miyake
authors: Mitsuhiro
authors: M
authors: Watanabe
authors: Ken
authors: K
authors: Shinmura
authors: Kazuo
authors: K
authors: Tsubota
mesh_terms: D000375:Aging / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000378:metabolism; D016207:Cytokines / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D003624:Darkness; D005786:Gene Expression Regulation; D006609:High Mobility Group Proteins / Q000235:genetics; D008027:Light; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D054409:Nicotinamide Phosphoribosyltransferase / Q000235:genetics; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism*; D012160:Retina / Q000378:metabolism* / Q000528:radiation effects*; D037761:Sirtuins / Q000235:genetics*; D014018:Tissue Distribution; D014157:Transcription Factors / Q000235:genetics
chemical_list: D016207:Cytokines; D004268:DNA-Binding Proteins; D006609:High Mobility Group Proteins; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C485290:Ppargc1a protein, mouse; D012333:RNA, Messenger; C081930:Tfam protein, mouse; D014157:Transcription Factors; D054409:Nicotinamide Phosphoribosyltransferase; C495867:nicotinamide phosphoribosyltransferase, mouse; D037761:Sirtuins
keywords: CT; DD condition; LD condition; Light; Metabolism; Mitochondria; NAD; Nampt; PGC1α; Retina; Sirtuins; Tfam; ZT; circadian time; constant dark condition; light/dark condition; nicotinamide adenine dinucleotide; nicotinamide phosphoribosyltransferase; peroxisome proliferator-activated receptor gamma coactivator; transcription factor A, mitochondrial; zeitgeber time