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Inhibition of mammalian S6 kinase by resveratrol suppresses autophagy.

Armour SM, Baur JA, Hsieh SN, Land-Bracha A, Thomas SM, Sinclair DA - Aging (Albany NY) (2009)

Bottom Line: A major challenge is to understand the biological processes and molecular pathways by which resveratrol induces these beneficial effects.Furthermore, co-administration of resveratrol with S6K1 knockdown does not produce an additive effect.These data indicate that S6K1 is important for the full induction of autophagy in mammals and raise the possibility that some of the beneficial effects of resveratrol are due to modulation of S6K1 activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Paul F. Glenn Laboratories for the Biological Mechanisms of Aging, Harvard Medical School, Boston, MA 02115, USA.

ABSTRACT
Resveratrol is a plant-derived polyphenol that promotes health and disease resistance in rodent models, and extends lifespan in lower organisms. A major challenge is to understand the biological processes and molecular pathways by which resveratrol induces these beneficial effects. Autophagy is a critical process by which cells turn over damaged components and maintain bioenergetic requirements. Disruption of the normal balance between pro- and anti-autophagic signals is linked to cancer, liver disease, and neurodegenerative disorders. Here we show that resveratrol attenuates autophagy in response to nutrient limitation or rapamycin in multiple cell lines through a pathway independent of a known target, SIRT1. In a large-scalein vitro kinase screen we identified p70 S6 kinase (S6K1) as a target of resveratrol. Blocking S6K1 activity by expression of a dominant-negative mutant or RNA interference is sufficient to disrupt autophagy to a similar extent as resveratrol. Furthermore, co-administration of resveratrol with S6K1 knockdown does not produce an additive effect. These data indicate that S6K1 is important for the full induction of autophagy in mammals and raise the possibility that some of the beneficial effects of resveratrol are due to modulation of S6K1 activity.

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Resveratrol does not affect autophagy in the absence of S6K1. (A) HEK293 GFPLC3 cells wereinfected with shRNA S6K1 lentivirus or control virusand treated with EBSS (Starved) for 4 hrs ± 50 μMresveratrol (Res). Representative fields at 63X(oil immersion) magnification are shown. (B) Quantificationof punctae/cell from (A) of at least 4 fields per treatmentare represented as a percentage of DMSO treated starved vectorcontrol cells. Error bars represent s.e.m. N.S. = notsignificant.
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Figure 7: Resveratrol does not affect autophagy in the absence of S6K1. (A) HEK293 GFPLC3 cells wereinfected with shRNA S6K1 lentivirus or control virusand treated with EBSS (Starved) for 4 hrs ± 50 μMresveratrol (Res). Representative fields at 63X(oil immersion) magnification are shown. (B) Quantificationof punctae/cell from (A) of at least 4 fields per treatmentare represented as a percentage of DMSO treated starved vectorcontrol cells. Error bars represent s.e.m. N.S. = notsignificant.

Mentions: To provide additional evidence that the effects ofresveratrol are mediated via S6K1, HEK293 cells infected with control virus ora virus encoding shRNA against S6K1 were treated with resveratrol and subjectedto nutrient withdrawal. Individually, S6K1 shRNA and resveratrol both dramaticallyreduced the number of GFP-LC3 punctae, and resveratrol treatment in the absenceof S6K1 produced no further decrease (Figure 7A). Quantification of punctaerevealed no statistically significant difference between any of theexperimental treatments, all of which were significantly different whencompared to control cells (Figure 7B). These data indicate that S6 kinase isrequired for the full induction of autophagy in response to nutrient withdrawalin mammals, and lend further support to the view that the reduced level ofautophagy in resveratrol-treated cells is due to inhibition of S6K1.


Inhibition of mammalian S6 kinase by resveratrol suppresses autophagy.

Armour SM, Baur JA, Hsieh SN, Land-Bracha A, Thomas SM, Sinclair DA - Aging (Albany NY) (2009)

Resveratrol does not affect autophagy in the absence of S6K1. (A) HEK293 GFPLC3 cells wereinfected with shRNA S6K1 lentivirus or control virusand treated with EBSS (Starved) for 4 hrs ± 50 μMresveratrol (Res). Representative fields at 63X(oil immersion) magnification are shown. (B) Quantificationof punctae/cell from (A) of at least 4 fields per treatmentare represented as a percentage of DMSO treated starved vectorcontrol cells. Error bars represent s.e.m. N.S. = notsignificant.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2806030&req=5

Figure 7: Resveratrol does not affect autophagy in the absence of S6K1. (A) HEK293 GFPLC3 cells wereinfected with shRNA S6K1 lentivirus or control virusand treated with EBSS (Starved) for 4 hrs ± 50 μMresveratrol (Res). Representative fields at 63X(oil immersion) magnification are shown. (B) Quantificationof punctae/cell from (A) of at least 4 fields per treatmentare represented as a percentage of DMSO treated starved vectorcontrol cells. Error bars represent s.e.m. N.S. = notsignificant.
Mentions: To provide additional evidence that the effects ofresveratrol are mediated via S6K1, HEK293 cells infected with control virus ora virus encoding shRNA against S6K1 were treated with resveratrol and subjectedto nutrient withdrawal. Individually, S6K1 shRNA and resveratrol both dramaticallyreduced the number of GFP-LC3 punctae, and resveratrol treatment in the absenceof S6K1 produced no further decrease (Figure 7A). Quantification of punctaerevealed no statistically significant difference between any of theexperimental treatments, all of which were significantly different whencompared to control cells (Figure 7B). These data indicate that S6 kinase isrequired for the full induction of autophagy in response to nutrient withdrawalin mammals, and lend further support to the view that the reduced level ofautophagy in resveratrol-treated cells is due to inhibition of S6K1.

Bottom Line: A major challenge is to understand the biological processes and molecular pathways by which resveratrol induces these beneficial effects.Furthermore, co-administration of resveratrol with S6K1 knockdown does not produce an additive effect.These data indicate that S6K1 is important for the full induction of autophagy in mammals and raise the possibility that some of the beneficial effects of resveratrol are due to modulation of S6K1 activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Paul F. Glenn Laboratories for the Biological Mechanisms of Aging, Harvard Medical School, Boston, MA 02115, USA.

ABSTRACT
Resveratrol is a plant-derived polyphenol that promotes health and disease resistance in rodent models, and extends lifespan in lower organisms. A major challenge is to understand the biological processes and molecular pathways by which resveratrol induces these beneficial effects. Autophagy is a critical process by which cells turn over damaged components and maintain bioenergetic requirements. Disruption of the normal balance between pro- and anti-autophagic signals is linked to cancer, liver disease, and neurodegenerative disorders. Here we show that resveratrol attenuates autophagy in response to nutrient limitation or rapamycin in multiple cell lines through a pathway independent of a known target, SIRT1. In a large-scalein vitro kinase screen we identified p70 S6 kinase (S6K1) as a target of resveratrol. Blocking S6K1 activity by expression of a dominant-negative mutant or RNA interference is sufficient to disrupt autophagy to a similar extent as resveratrol. Furthermore, co-administration of resveratrol with S6K1 knockdown does not produce an additive effect. These data indicate that S6K1 is important for the full induction of autophagy in mammals and raise the possibility that some of the beneficial effects of resveratrol are due to modulation of S6K1 activity.

Show MeSH
Related in: MedlinePlus