In addition, dietary restriction [9], [10] and mTOR inhibition, related conditions owing to the biological function of mTOR, increase longevity in a number of model systems. total cpm in the resveratrol media and PBS washes. The results are shown as the mean SD. *P<0.05 versus control as determined by ANOVA.(TIF) pone.0029513.s001.tif (16M) GUID:?5A8694AF-303D-41BE-A667-C8AD2E1928FA Figure S2: The effect of EX527 on the effect of resveratrol. were analyzed by immunoprecipitation of p53 followed by Western immunoblotting for acetylated and total p53.(TIF) pone.0029513.s002.tif (2.2M) GUID:?2CBF2570-193E-47E0-BF84-EC4987104A5D Figure S3: Independent repetition of the effect of resveratrol and rapamycin on integrity of mTORC1. Cell lysates were analyzed by immunoprecipitation of mTOR followed by immunoblotting for raptor and mTOR.(TIF) pone.0029513.s003.tif (131K) GUID:?1C375AF3-AA1D-4320-95E6-A374C2A46329 Abstract Resveratrol is a plant-derived polyphenol that extends lifespan and healthspan in model organism. Despite extensive investigation, the biological processes mediating resveratrol's effects have yet to be elucidated. Because repression of translation shares many of resveratrol's beneficial effects, we hypothesized that resveratrol was a modulator of protein synthesis. We studied the effect of the drug on the H4-II-E rat hepatoma cell line. Initial studies showed that resveratrol inhibited global protein synthesis. Given the role of the mammalian Target of Rapamycin (mTOR) in regulating protein synthesis, we examined the effect of resveratrol on mTOR signaling. Resveratrol inhibited mTOR self-phosphorylation and the phosphorylation of mTOR targets S6K1 and eIF4E-BP1. It attenuated the formation of the translation initiation complex eIF4F and increased the phosphorylation of eIF2. The latter event, also a mechanism for translation inhibition, was not Gingerol recapitulated by mTOR inhibitors. The effects on mTOR signaling were independent of effects on AMP-activated kinase or AKT. We conclude that resveratrol is an inhibitor of global protein synthesis, and that this effect is mediated through modulation of mTOR-dependent and independent signaling. Introduction Resveratrol is a plant-derived polyphenol found in grapes, red wine, and other foods. This compound extends the lifespan of lower organisms (yeast, worms, flies and fish) [1]C[3] and protects rodents from a variety of age-related diseases, including cancer, cardiovascular disease, obesity and diabetes [4]C[8]. Resveratrol is considered a mimetic for some of the beneficial effects of caloric restriction (reduction of food intake without malnutrition), which is the only environmental intervention known to extend longevity in a wide range of organisms [9], [10]. A relationship between extended longevity and decreased translation has been observed in a variety of conditions, including caloric restriction [11], [12] and inhibition of the nutrientCsensing kinase termed mTOR (mammalian Target of Rapamycin) [11], [13]C[18]. In fact, recent studies have shown that continuous administration of rapamycin, a specific inhibitor of mTOR Complex 1 (mTORC1), increases lifespan in mice [19] and flies [18]. mTORC1 is one of the two complexes, the other being mTORC2, that account for signaling via mTOR. mTORC1 responds to growth factors, cellular energy and nutrient status by stimulating, Gingerol among other processes, the initiation of mRNA translation [20]. This involves mTORC1-mediated phosphorylation of the eukaryotic initiation factor 4E-binding protein 1 (eIF4E-BP1) and ribosomal protein S6 kinase 1 (S6K1). Phosphorylation of eIF4E-BP1 leads to its release from the cap-binding factor eIF4E, thereby upregulating cap-dependent translation [21]. Loss of function of eIF4E-BP or S6K1 Rabbit polyclonal to PFKFB3 retards the aging process in flies and mice [12], [17], [18], suggesting that attenuation of signaling through a single mTOR target is sufficient to extend longevity. mTOR signaling can be activated in response to the serine-threonine kinase AKT. In response to insulin, phosphatidylinositol-3 kinase (PI3K) is activated, leading to the activation of phosphoinositide-dependent kinase-1 (PDK-1), which in turn phosphorylates AKT at Thr 308. Resulting activation of AKT inhibits the formation of the tuberous sclerosis comple/2 (TSC) and de-represses mTORC1 activity [22]. Conversely, low cellular energy levels suppress mTORC1 activity via activation of AMP-activated kinase (AMPK). AMPK activation mediates TSC2 phosphorylation, which results in down regulation of mTORC1 activity [22]. In addition, AMPK is also able to directly phosphorylate the mTORC1 binding partner Raptor Gingerol [23]..