title: Lipoic acid entrains the hepatic circadian clock and lipid metabolic proteins that have been desynchronized with advanced age.
abstract: It is well established that lipid metabolism is controlled, in part, by circadian clocks. However, circadian clocks lose temporal precision with age and correlates with elevated incidence in dyslipidemia and metabolic syndrome in older adults. Because our lab has shown that lipoic acid (LA) improves lipid homeostasis in aged animals, we hypothesized that LA affects the circadian clock to achieve these results. We fed 24 month old male F344 rats a diet supplemented with 0.2% (w/w) LA for 2 weeks prior to sacrifice and quantified hepatic circadian clock protein levels and clock-controlled lipid metabolic enzymes. LA treatment caused a significant phase-shift in the expression patterns of the circadian clock proteins Period (Per) 2, Brain and Muscle Arnt-Like1 (BMAL1), and Reverse Erythroblastosis virus (Rev-erb) β without altering the amplitude of protein levels during the light phase of the day. LA also significantly altered the oscillatory patterns of clock-controlled proteins associated with lipid metabolism. The level of peroxisome proliferator-activated receptor (PPAR) α was significantly increased and acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) were both significantly reduced, suggesting that the LA-supplemented aged animals are in a catabolic state. We conclude that LA remediates some of the dyslipidemic processes associated with advanced age, and this mechanism may be at least partially through entrainment of circadian clocks.
authors.affiliation: Linus Pauling Institute, Oregon State University, United States.
authors.forename: Dove
authors.initials: D
authors.lastname: Keith
authors.affiliation: Linus Pauling Institute, Oregon State University, United States.
authors.forename: Liam
authors.initials: L
authors.lastname: Finlay
authors.affiliation: Linus Pauling Institute, Oregon State University, United States.
authors.forename: Judy
authors.initials: J
authors.lastname: Butler
authors.affiliation: Linus Pauling Institute, Oregon State University, United States; Biochemistry Biophysics Department, Oregon State University, United States.
authors.forename: Luis
authors.initials: L
authors.lastname: Gómez
authors.affiliation: Linus Pauling Institute, Oregon State University, United States; Biochemistry Biophysics Department, Oregon State University, United States.
authors.forename: Eric
authors.initials: E
authors.lastname: Smith
authors.affiliation: Linus Pauling Institute, Oregon State University, United States.
authors.forename: Régis
authors.initials: R
authors.lastname: Moreau
authors.affiliation: Linus Pauling Institute, Oregon State University, United States; Biochemistry Biophysics Department, Oregon State University, United States. Electronic address: Tory.Hagen@oregonstate.edu.
authors.forename: Tory
authors.initials: T
authors.lastname: Hagen
mesh_terms: D000284:Administration, Oral; D000375:Aging / Q000502:physiology*; D000818:Animals; D056926:CLOCK Proteins / Q000378:metabolism*; D057906:Circadian Clocks / Q000502:physiology*; D025461:Feedback, Physiological / Q000187:drug effects / Q000502:physiology; D050356:Lipid Metabolism / Q000187:drug effects / Q000502:physiology*; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344; D008063:Thioctic Acid / Q000008:administration & dosage*
chemical_list: D008063:Thioctic Acid; D056926:CLOCK Proteins
keywords: Aging; Circadian; Corticosterone; Dyslipidemia; Entrainment; Peroxisome proliferator-activated receptor