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BMAL1-dependent regulation of the mTOR signaling pathway delays aging.

Khapre RV, Kondratova AA, Patel S, Dubrovsky Y, Wrobel M, Antoch MP, Kondratov RV - Aging (Albany NY) (2014)

Bottom Line: Increased mTOR signaling is associated with accelerated aging; in accordance with that, treatment with the mTORC1 inhibitor rapamycin increased lifespan of Bmal1-/- mice by 50%.Our data suggest that BMAL1 is a negative regulator of mTORC1 signaling.We propose that the circadian clock controls the activity of the mTOR pathway through BMAL1-dependent mechanisms and this regulation is important for control of aging and metabolism.

View Article: PubMed Central - PubMed

Affiliation: Center for Gene Regulation in Health and Diseases, BGES, Cleveland State University, Cleveland, OH.

ABSTRACT
The circadian clock, an internal time-keeping system, has been linked with control of aging, but molecular mechanisms of regulation are not known. BMAL1 is a transcriptional factor and core component of the circadian clock; BMAL1 deficiency is associated with premature aging and reduced lifespan. Here we report that activity of mammalian Target of Rapamycin Complex 1 (mTORC1) is increased upon BMAL1 deficiency both in vivo and in cell culture. Increased mTOR signaling is associated with accelerated aging; in accordance with that, treatment with the mTORC1 inhibitor rapamycin increased lifespan of Bmal1-/- mice by 50%. Our data suggest that BMAL1 is a negative regulator of mTORC1 signaling. We propose that the circadian clock controls the activity of the mTOR pathway through BMAL1-dependent mechanisms and this regulation is important for control of aging and metabolism.

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Deregulated mTOR signaling contributes to accelerated aging of Bmal1−/− mice(a) Treatment with rapamycin suppresses TORC1 activity in both wild type and Bmal1−/− (KO) cells. Cells were treated with indicated concentrations of rapamycin for 4 hrs, protein phosphorylation in cellular extracts were analyzed by western blotting procedure with antibodies recognizing the indicated proteins or protein modifications. U/t untreated cells. (b) Effect of rapamycin treatment on proliferation of wild type (black diamonds) and Bmal1−/− (KO) (grey squares) cells. Cells were grown for 72 hrs in regular growth media with indicated concentrations of rapamycin. Cell biomass was assayed by crystal violet incorporation. Data represent average and standard deviations for 4 replicates. The experiment was repeated 3 times with similar results. a.u. – arbitrary units. * - statistically significant difference between genotypes. (c) Kaplan-Meyer survival curves of Bmal1−/− mice treated with water (N = 73) or Rapatar in drinking water (N = 31). The difference between the survival curves is statistically significant according to logrank test.
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Figure 6: Deregulated mTOR signaling contributes to accelerated aging of Bmal1−/− mice(a) Treatment with rapamycin suppresses TORC1 activity in both wild type and Bmal1−/− (KO) cells. Cells were treated with indicated concentrations of rapamycin for 4 hrs, protein phosphorylation in cellular extracts were analyzed by western blotting procedure with antibodies recognizing the indicated proteins or protein modifications. U/t untreated cells. (b) Effect of rapamycin treatment on proliferation of wild type (black diamonds) and Bmal1−/− (KO) (grey squares) cells. Cells were grown for 72 hrs in regular growth media with indicated concentrations of rapamycin. Cell biomass was assayed by crystal violet incorporation. Data represent average and standard deviations for 4 replicates. The experiment was repeated 3 times with similar results. a.u. – arbitrary units. * - statistically significant difference between genotypes. (c) Kaplan-Meyer survival curves of Bmal1−/− mice treated with water (N = 73) or Rapatar in drinking water (N = 31). The difference between the survival curves is statistically significant according to logrank test.

Mentions: Previously we reported that Bmal1−/− mice developed premature aging and had dramatically reduced lifespan [13]; thus, our current data suggest that the reduced longevity in Bmal1−/− mice may result from the constitutively elevated mTORC1 signaling. To test this hypothesis we decided to check whether pharmacological suppression of the mTOR signaling by rapamycin (a potent and highly specific inhibitor of mTORC1 kinase activity [32,33]) would increase the lifespan of Bmal1−/− mice. First we assayed the effect of rapamycin on the BMAL1-dependent regulation of mTORC1 in cell culture. The treatment of cells with rapamycin reduced mTORC1 signaling in both wild type and Bmal1−/− cells (Figure 6a). Bmal1−/− fibroblasts were also more sensitive to growth inhibition by rapamycin than the wild type cells (Figure 6b), supporting the role of mTORC1 in the observed difference between wild type and BMAL1-deficient cells.


BMAL1-dependent regulation of the mTOR signaling pathway delays aging.

Khapre RV, Kondratova AA, Patel S, Dubrovsky Y, Wrobel M, Antoch MP, Kondratov RV - Aging (Albany NY) (2014)

Deregulated mTOR signaling contributes to accelerated aging of Bmal1−/− mice(a) Treatment with rapamycin suppresses TORC1 activity in both wild type and Bmal1−/− (KO) cells. Cells were treated with indicated concentrations of rapamycin for 4 hrs, protein phosphorylation in cellular extracts were analyzed by western blotting procedure with antibodies recognizing the indicated proteins or protein modifications. U/t untreated cells. (b) Effect of rapamycin treatment on proliferation of wild type (black diamonds) and Bmal1−/− (KO) (grey squares) cells. Cells were grown for 72 hrs in regular growth media with indicated concentrations of rapamycin. Cell biomass was assayed by crystal violet incorporation. Data represent average and standard deviations for 4 replicates. The experiment was repeated 3 times with similar results. a.u. – arbitrary units. * - statistically significant difference between genotypes. (c) Kaplan-Meyer survival curves of Bmal1−/− mice treated with water (N = 73) or Rapatar in drinking water (N = 31). The difference between the survival curves is statistically significant according to logrank test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3927809&req=5

Figure 6: Deregulated mTOR signaling contributes to accelerated aging of Bmal1−/− mice(a) Treatment with rapamycin suppresses TORC1 activity in both wild type and Bmal1−/− (KO) cells. Cells were treated with indicated concentrations of rapamycin for 4 hrs, protein phosphorylation in cellular extracts were analyzed by western blotting procedure with antibodies recognizing the indicated proteins or protein modifications. U/t untreated cells. (b) Effect of rapamycin treatment on proliferation of wild type (black diamonds) and Bmal1−/− (KO) (grey squares) cells. Cells were grown for 72 hrs in regular growth media with indicated concentrations of rapamycin. Cell biomass was assayed by crystal violet incorporation. Data represent average and standard deviations for 4 replicates. The experiment was repeated 3 times with similar results. a.u. – arbitrary units. * - statistically significant difference between genotypes. (c) Kaplan-Meyer survival curves of Bmal1−/− mice treated with water (N = 73) or Rapatar in drinking water (N = 31). The difference between the survival curves is statistically significant according to logrank test.
Mentions: Previously we reported that Bmal1−/− mice developed premature aging and had dramatically reduced lifespan [13]; thus, our current data suggest that the reduced longevity in Bmal1−/− mice may result from the constitutively elevated mTORC1 signaling. To test this hypothesis we decided to check whether pharmacological suppression of the mTOR signaling by rapamycin (a potent and highly specific inhibitor of mTORC1 kinase activity [32,33]) would increase the lifespan of Bmal1−/− mice. First we assayed the effect of rapamycin on the BMAL1-dependent regulation of mTORC1 in cell culture. The treatment of cells with rapamycin reduced mTORC1 signaling in both wild type and Bmal1−/− cells (Figure 6a). Bmal1−/− fibroblasts were also more sensitive to growth inhibition by rapamycin than the wild type cells (Figure 6b), supporting the role of mTORC1 in the observed difference between wild type and BMAL1-deficient cells.

Bottom Line: Increased mTOR signaling is associated with accelerated aging; in accordance with that, treatment with the mTORC1 inhibitor rapamycin increased lifespan of Bmal1-/- mice by 50%.Our data suggest that BMAL1 is a negative regulator of mTORC1 signaling.We propose that the circadian clock controls the activity of the mTOR pathway through BMAL1-dependent mechanisms and this regulation is important for control of aging and metabolism.

View Article: PubMed Central - PubMed

Affiliation: Center for Gene Regulation in Health and Diseases, BGES, Cleveland State University, Cleveland, OH.

ABSTRACT
The circadian clock, an internal time-keeping system, has been linked with control of aging, but molecular mechanisms of regulation are not known. BMAL1 is a transcriptional factor and core component of the circadian clock; BMAL1 deficiency is associated with premature aging and reduced lifespan. Here we report that activity of mammalian Target of Rapamycin Complex 1 (mTORC1) is increased upon BMAL1 deficiency both in vivo and in cell culture. Increased mTOR signaling is associated with accelerated aging; in accordance with that, treatment with the mTORC1 inhibitor rapamycin increased lifespan of Bmal1-/- mice by 50%. Our data suggest that BMAL1 is a negative regulator of mTORC1 signaling. We propose that the circadian clock controls the activity of the mTOR pathway through BMAL1-dependent mechanisms and this regulation is important for control of aging and metabolism.

Show MeSH
Related in: MedlinePlus