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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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BMAL1 is negative regulator of TORC1 activity in cells(a) Phosphorylation and total protein level of ribosomal S6 protein in primary lung fibroblasts isolated from wild type and Bmal1−/− mice. Protein phosphorylation in cellular extracts were assayed by western blotting procedure with antibodies recognizing the indicated proteins or protein modifications WT1, WT2, KO1, KO2 and KO3 represent independently isolated populations fibroblasts isolated from wild type (WT) and Bmal1−/− (KO) mice. Cells were incubated in DMEM with 10% FBS (+) or serum deprived for 24 hrs (−). (b) and (c) Wild type (WT) and Bmal1−/− (KO) fibroblasts were subject to amino acids (b) or serum (c) withdrawal for indicated period of time. Kinetics of changes in phosphorylation of mTORC1 downstream targets are shown on the representative western blotting.
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Figure 1: BMAL1 is negative regulator of TORC1 activity in cells(a) Phosphorylation and total protein level of ribosomal S6 protein in primary lung fibroblasts isolated from wild type and Bmal1−/− mice. Protein phosphorylation in cellular extracts were assayed by western blotting procedure with antibodies recognizing the indicated proteins or protein modifications WT1, WT2, KO1, KO2 and KO3 represent independently isolated populations fibroblasts isolated from wild type (WT) and Bmal1−/− (KO) mice. Cells were incubated in DMEM with 10% FBS (+) or serum deprived for 24 hrs (−). (b) and (c) Wild type (WT) and Bmal1−/− (KO) fibroblasts were subject to amino acids (b) or serum (c) withdrawal for indicated period of time. Kinetics of changes in phosphorylation of mTORC1 downstream targets are shown on the representative western blotting.

Mentions: Figure 1a shows results obtained in several independently isolated populations of lung fibroblasts; phosphorylation of S6 protein was significantly higher in Bmal1−/− cells, suggesting that BMAL1 is a negative regulator of mTOR signaling. Since mTORC1 activity was shown to be sensitive to growth factor and amino acid withdrawal [28-30], to investigate the role of BMAL1 in these processes we subjected wild type and Bmal1−/− cells for serum or amino acid starvation. As expected, amino acid (Figure 1b) or serum (Figure 1c) starvation resulted in suppression of phosphorylation of the mTORC1 targets in both cell types. However, the level of phosphorylation and kinetics of response to starvation displayed prominent differences. When compared to wild type, Bmal1−/− cells demonstrated increased phosphorylation for mTORC1 targets (S6K1 T389 site and 4EBP-1 T37/46 sites), but showed no difference in S6K1 phosphorylation on the MAPK-specific Thr421/Ser424 site, suggesting that the regulation of mTORC1 activity by BMAL1 is highly specific.


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)

BMAL1 is negative regulator of TORC1 activity in cells(a) Phosphorylation and total protein level of ribosomal S6 protein in primary lung fibroblasts isolated from wild type and Bmal1−/− mice. Protein phosphorylation in cellular extracts were assayed by western blotting procedure with antibodies recognizing the indicated proteins or protein modifications WT1, WT2, KO1, KO2 and KO3 represent independently isolated populations fibroblasts isolated from wild type (WT) and Bmal1−/− (KO) mice. Cells were incubated in DMEM with 10% FBS (+) or serum deprived for 24 hrs (−). (b) and (c) Wild type (WT) and Bmal1−/− (KO) fibroblasts were subject to amino acids (b) or serum (c) withdrawal for indicated period of time. Kinetics of changes in phosphorylation of mTORC1 downstream targets are shown on the representative western blotting.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: BMAL1 is negative regulator of TORC1 activity in cells(a) Phosphorylation and total protein level of ribosomal S6 protein in primary lung fibroblasts isolated from wild type and Bmal1−/− mice. Protein phosphorylation in cellular extracts were assayed by western blotting procedure with antibodies recognizing the indicated proteins or protein modifications WT1, WT2, KO1, KO2 and KO3 represent independently isolated populations fibroblasts isolated from wild type (WT) and Bmal1−/− (KO) mice. Cells were incubated in DMEM with 10% FBS (+) or serum deprived for 24 hrs (−). (b) and (c) Wild type (WT) and Bmal1−/− (KO) fibroblasts were subject to amino acids (b) or serum (c) withdrawal for indicated period of time. Kinetics of changes in phosphorylation of mTORC1 downstream targets are shown on the representative western blotting.
Mentions: Figure 1a shows results obtained in several independently isolated populations of lung fibroblasts; phosphorylation of S6 protein was significantly higher in Bmal1−/− cells, suggesting that BMAL1 is a negative regulator of mTOR signaling. Since mTORC1 activity was shown to be sensitive to growth factor and amino acid withdrawal [28-30], to investigate the role of BMAL1 in these processes we subjected wild type and Bmal1−/− cells for serum or amino acid starvation. As expected, amino acid (Figure 1b) or serum (Figure 1c) starvation resulted in suppression of phosphorylation of the mTORC1 targets in both cell types. However, the level of phosphorylation and kinetics of response to starvation displayed prominent differences. When compared to wild type, Bmal1−/− cells demonstrated increased phosphorylation for mTORC1 targets (S6K1 T389 site and 4EBP-1 T37/46 sites), but showed no difference in S6K1 phosphorylation on the MAPK-specific Thr421/Ser424 site, suggesting that the regulation of mTORC1 activity by BMAL1 is highly specific.

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