SRT1720, SRT2183, SRT1460, and resveratrol are not direct activators of SIRT1.
Sirtuins catalyze NAD(+)-dependent protein deacetylation and are critical regulators of transcription, apoptosis, metabolism, and aging. There are seven human sirtuins (SIRT1-7), and SIRT1 has been implicated as a key mediator of the pathways downstream of calorie restriction that have been shown to delay the onset and reduce the incidence of age-related diseases such as type 2 diabetes. Increasing SIRT1 activity, either by transgenic overexpression of the Sirt1 gene in mice or by pharmacological activation by small molecule activators resveratrol and SRT1720, has shown beneficial effects in rodent models of type 2 diabetes, indicating that SIRT1 may represent an attractive therapeutic target. Herein, we have assessed purported SIRT1 activators by employing biochemical assays utilizing native substrates, including a p53-derived peptide substrate lacking a fluorophore as well as the purified native full-length protein substrates p53 and acetyl-CoA synthetase1. SRT1720, its structurally related compounds SRT2183 and SRT1460, and resveratrol do not lead to apparent activation of SIRT1 with native peptide or full-length protein substrates, whereas they do activate SIRT1 with peptide substrate containing a covalently attached fluorophore. Employing NMR, surface plasmon resonance, and isothermal calorimetry techniques, we provide evidence that these compounds directly interact with fluorophore-containing peptide substrates. Furthermore, we demonstrate that SRT1720 neither lowers plasma glucose nor improves mitochondrial capacity in mice fed a high fat diet. SRT1720, SRT2183, SRT1460, and resveratrol exhibit multiple off-target activities against receptors, enzymes, transporters, and ion channels. Taken together, we conclude that SRT1720, SRT2183, SRT1460, and resveratrol are not direct activators of SIRT1.
Pacholec
Michelle
M
Department of Cardiovascular, Pfizer Global Research and Development, Groton, Connecticut 06340, USA.
Bleasdale
John E
JE
Chrunyk
Boris
B
Cunningham
David
D
Flynn
Declan
D
Garofalo
Robert S
RS
Griffith
David
D
Griffor
Matt
M
Loulakis
Pat
P
Pabst
Brandon
B
Qiu
Xiayang
X
Stockman
Brian
B
Thanabal
Venkataraman
V
Varghese
Alison
A
Ward
Jessica
J
Withka
Jane
J
Ahn
Kay
K
D000107:Acetylation / Q000187:drug effects; D000494:Allosteric Regulation / Q000187:drug effects; D000818:Animals; D001786:Blood Glucose / Q000187:drug effects; D002151:Calorimetry; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000378:metabolism; D004041:Dietary Fats / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D006576:Heterocyclic Compounds, 4 or More Rings / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D051379:Mice; D008820:Mice, Obese; D019906:Nuclear Magnetic Resonance, Biomolecular; D000077185:Resveratrol; D012235:Rhodamines; D056564:Sirtuin 1 / Q000378:metabolism*; D013267:Stilbenes / Q000737:chemistry / Q000494:pharmacology*; D013379:Substrate Specificity; D020349:Surface Plasmon Resonance; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
C114557:5-carboxytetramethylrhodamine succinimidyl ester; D001786:Blood Glucose; D004041:Dietary Fats; D004791:Enzyme Inhibitors; D006576:Heterocyclic Compounds, 4 or More Rings; D012235:Rhodamines; C525424:SRT1460; C525422:SRT1720; C525423:SRT2183; D013267:Stilbenes; D016159:Tumor Suppressor Protein p53; C447939:SIRT1 protein, human; D056564:Sirtuin 1; D000077185:Resveratrol