Autophagy Induction by SIRT6 through Attenuation of Insulin-like Growth Factor Signaling Is Involved in the Regulation of Human Bronchial Epithelial Cell Senescence
| Autor: | Hiroshi Wakui, Jun Araya, Jun Hirano, Yutaka Yoshii, Naoki Takasaka, Saburo Ito, Makoto Odaka, Takanori Numata, Katsutoshi Nakayama, Yoko Yumino, Noriki Kamiya, Jun Kojima, Kenji Kobayashi, Shunsuke Minagawa, Makoto Kawaishi, Yumi Kaneko, Kazuyoshi Kuwano, Toshiaki Morikawa, Chikako Tsurushige, Stephen L. Nishimura, Yusuke Kurita, Kenichiro Shimizu, Satoko Fujii, Hiromichi Hara |
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| Rok vydání: | 2014 |
| Předmět: |
Senescence
Small interfering RNA medicine.medical_treatment Vital Capacity Immunology ATG5 Bronchi Biology Autophagy-Related Protein 5 Pulmonary Disease Chronic Obstructive Forced Expiratory Volume Smoke Tobacco Autophagy medicine Humans Sirtuins Immunology and Allergy Insulin-Like Growth Factor I RNA Small Interfering Cells Cultured Cellular Senescence PI3K/AKT/mTOR pathway Gene knockdown TOR Serine-Threonine Kinases Growth factor Acetylation Epithelial Cells Cell biology Gene Expression Regulation Mutation RNA Interference Histone deacetylase activity Microtubule-Associated Proteins Protein Processing Post-Translational Proto-Oncogene Proteins c-akt Signal Transduction |
| Zdroj: | The Journal of Immunology. 192:958-968 |
| ISSN: | 1550-6606 0022-1767 |
| Popis: | Cigarette smoke (CS)–induced cellular senescence has been implicated in the pathogenesis of chronic obstructive pulmonary disease, and SIRT6, a histone deacetylase, antagonizes this senescence, presumably through the attenuation of insulin-like growth factor (IGF)-Akt signaling. Autophagy controls cellular senescence by eliminating damaged cellular components and is negatively regulated by IGF-Akt signaling through the mammalian target of rapamycin (mTOR). SIRT1, a representative sirtuin family, has been demonstrated to activate autophagy, but a role for SIRT6 in autophagy activation has not been shown. Therefore, we sought to investigate the regulatory role for SIRT6 in autophagy activation during CS-induced cellular senescence. SIRT6 expression levels were modulated by cDNA and small interfering RNA transfection in human bronchial epithelial cells (HBECs). Senescence-associated β-galactosidase staining and Western blotting of p21 were performed to evaluate senescence. We demonstrated that SIRT6 expression levels were decreased in lung homogenates from chronic obstructive pulmonary disease patients, and SIRT6 expression levels correlated significantly with the percentage of forced expiratory volume in 1 s/forced vital capacity. CS extract (CSE) suppressed SIRT6 expression in HBECs. CSE-induced HBEC senescence was inhibited by SIRT6 overexpression, whereas SIRT6 knockdown and mutant SIRT6 (H133Y) without histone deacetylase activity enhanced HBEC senescence. SIRT6 overexpression induced autophagy via attenuation of IGF-Akt-mTOR signaling. Conversely, SIRT6 knockdown and overexpression of a mutant SIRT6 (H133Y) inhibited autophagy. Autophagy inhibition by knockdown of ATG5 and LC3B attenuated the antisenescent effect of SIRT6 overexpression. These results suggest that SIRT6 is involved in CSE-induced HBEC senescence via autophagy regulation, which can be attributed to attenuation of IGF-Akt-mTOR signaling. |
| Databáze: | OpenAIRE |
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