title: The role of calorie restriction and SIRT1 in prion-mediated neurodegeneration.
abstract: A central focus of aging research is to determine how calorie restriction (CR) extends lifespan and delays diseases of aging. SIRT1, the mammalian ortholog of Sir2 in yeast, is a longevity factor which mediates dietary restriction in diverse species. In addition, SIRT1 plays a protective role in several models of neurodegenerative disease. We tested the role of SIRT1 in mediating the effects of CR in a mouse model of prion disease. Prion diseases are protein misfolding disorders of the central nervous system with many similarities to other neurodegenerative diseases, including deposition of aggregated protein, gliosis, and loss of synapses and neurons. We report that the onset of prion disease is delayed by CR and in the SIRT1 KO mice fed ad libitum. CR exerts no further effect on the SIRT1 KO strain, suggesting the effects of CR and SIRT1 deletion are mechanistically coupled. In conjunction, SIRT1 is downregulated in certain brain regions of CR mice. The expression of PrP mRNA and protein is reduced in the brains of CR mice and in SIRT1 knockout mice, suggesting a possible mechanism for the delayed onset of disease, as PrP levels are a critical determinant of how quickly mice succumb to prion disease. Surprisingly, CR greatly shortens the duration of clinical symptoms of prion disease and ultimately shortens lifespan of prion-inoculated mice in a manner that is independent of SIRT1. Taken together, our results suggest a more complex interplay between CR, SIRT1, and neurodegenerative diseases than previously appreciated.
authors.affiliation: Department of Biology, MIT, Cambridge, MA 02139, USA.
authors.forename: Danica
authors.initials: D
authors.lastname: Chen
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Steele
authors.forename: Gregor
authors.initials: G
authors.lastname: Hutter
authors.forename: Joanne
authors.initials: J
authors.lastname: Bruno
authors.forename: Arvind
authors.initials: A
authors.lastname: Govindarajan
authors.forename: Erin
authors.initials: E
authors.lastname: Easlon
authors.forename: Su-Ju
authors.initials: SJ
authors.lastname: Lin
authors.forename: Adriano
authors.initials: A
authors.lastname: Aguzzi
authors.forename: Susan
authors.initials: S
authors.lastname: Lindquist
authors.forename: Leonard
authors.initials: L
authors.lastname: Guarente
mesh_terms: D000375:Aging / Q000235:genetics; D000818:Animals; D015153:Blotting, Western; D031204:Caloric Restriction / Q000009:adverse effects*; D005786:Gene Expression Regulation / Q000502:physiology; D008136:Longevity / Q000235:genetics / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout / Q000378:metabolism; D009410:Nerve Degeneration / Q000235:genetics / Q000378:metabolism*; D017096:Prion Diseases / Q000235:genetics / Q000378:metabolism*; D056564:Sirtuin 1; D037761:Sirtuins / Q000235:genetics / Q000378:metabolism*
chemical_list: C470545:Sirt1 protein, mouse; D056564:Sirtuin 1; D037761:Sirtuins
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