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Mitchell SJ, Martin-Montalvo A, Mercken EM, Palacios HH, Ward TM, Abulwerdi G, Minor RK, Vlasuk GP, Ellis JL, Sinclair DA, Dawson J, Allison DB, Zhang Y, Becker KG, Bernier M, de Cabo R. The SIRT1 activator SRT1720 extends lifespan and improves health of mice fed a standard diet. Cell Rep 2014; 6:836-43. [PMID: 24582957 DOI: 10.1016/j.celrep.2014.01.031] [Citation(s) in RCA: 285] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 12/16/2013] [Accepted: 01/23/2014] [Indexed: 12/28/2022] Open
Abstract
The prevention or delay of the onset of age-related diseases prolongs survival and improves quality of life while reducing the burden on the health care system. Activation of sirtuin 1 (SIRT1), an NAD(+)-dependent deacetylase, improves metabolism and confers protection against physiological and cognitive disturbances in old age. SRT1720 is a specific SIRT1 activator that has health and lifespan benefits in adult mice fed a high-fat diet. We found extension in lifespan, delayed onset of age-related metabolic diseases, and improved general health in mice fed a standard diet after SRT1720 supplementation. Inhibition of proinflammatory gene expression in both liver and muscle of SRT1720-treated animals was noted. SRT1720 lowered the phosphorylation of NF-κB pathway regulators in vitro only when SIRT1 was functionally present. Combined with our previous work, the current study further supports the beneficial effects of SRT1720 on health across the lifespan in mice.
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Affiliation(s)
- Sarah J Mitchell
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MD 21224, USA; Kolling Institute of Medical Research, Royal North Shore Hospital, St Leonards, NSW 2065, Australia; Sydney Medical School, University of Sydney, Sydney, NSW 2006, Australia
| | - Alejandro Martin-Montalvo
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Evi M Mercken
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Hector H Palacios
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Theresa M Ward
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Gelareh Abulwerdi
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Robin K Minor
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - George P Vlasuk
- Sirtris, a GSK company, 200 Technology Square, Cambridge, MA 02139, USA
| | - James L Ellis
- Sirtris, a GSK company, 200 Technology Square, Cambridge, MA 02139, USA
| | - David A Sinclair
- Glenn Labs for the Biological Mechanisms of Aging, Harvard Medical School, Boston, MA 02115, USA
| | - John Dawson
- School of Public Health, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - David B Allison
- School of Public Health, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Yongqing Zhang
- Gene Expression and Genomics Unit, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Kevin G Becker
- Gene Expression and Genomics Unit, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Michel Bernier
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Rafael de Cabo
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MD 21224, USA.
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252
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Combined exposure to cigarette smoke and nontypeable Haemophilus influenzae drives development of a COPD phenotype in mice. Respir Res 2014; 15:11. [PMID: 24495712 PMCID: PMC3926338 DOI: 10.1186/1465-9921-15-11] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 02/03/2014] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Cigarette smoke (CS) is the major etiologic factor of chronic obstructive pulmonary disease (COPD). CS-exposed mice develop emphysema and mild pulmonary inflammation but no airway obstruction, which is also a prominent feature of COPD. Therefore, CS may interact with other factors, particularly respiratory infections, in the pathogenesis of airway remodeling in COPD. METHODS C57BL/6 mice were exposed to CS for 2 h a day, 5 days a week for 8 weeks. Mice were also exposed to heat-killed non-typeable H. influenzae (HK-NTHi) on days 7 and 21. One day after the last exposure to CS, mice were sacrificed and lung inflammation and mechanics, emphysematous changes, and goblet cell metaplasia were assessed. Mice exposed to CS or HK-NTHi alone or room air served as controls. To determine the susceptibility to viral infections, we also challenged these mice with rhinovirus (RV). RESULTS Unlike mice exposed to CS or HK-NTHi alone, animals exposed to CS/HK-NTHi developed emphysema, lung inflammation and goblet cell metaplasia in both large and small airways. CS/HK-NTHi-exposed mice also expressed increased levels of mucin genes and cytokines compared to mice in other groups. CS/HK-NTHi-exposed mice infected with RV demonstrated increased viral persistence, sustained neutrophilia, and further increments in mucin gene and chemokine expression compared to other groups. CONCLUSIONS These findings indicate that in addition to CS, bacteria may also contribute to development of COPD, particularly changes in airways. Mice exposed to CS/HK-NTHi are also more susceptible to subsequent viral infection than mice exposed to either CS or HK-NTHi alone.
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253
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Afanas’ev I. New nucleophilic mechanisms of ros-dependent epigenetic modifications: comparison of aging and cancer. Aging Dis 2014; 5:52-62. [PMID: 24490117 PMCID: PMC3901614 DOI: 10.14336/ad.2014.050052] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 10/07/2013] [Accepted: 10/16/2013] [Indexed: 12/31/2022] Open
Abstract
It has been shown that ROS (reactive oxygen species, superoxide and hydrogen peroxide) regulate major epigenetic processes, DNA methylation and histone acetylation, although the mechanism of ROS action (ROS signaling) is still unknown. Both DNA methylation and histone acetylation are nucleophilic processes and therefore ROS signaling through typical free radical processes, for example hydrogen atom abstraction is impossible. However, being "super-nucleophile" superoxide can participate in these reactions. Now we propose new nucleophilic mechanisms of DNA methylation and histone modification. During DNA methylation superoxide can deprotonate the cytosine molecule at C-5 position and by this accelerate the reaction of DNA with the positive-charged intermediate S-adenosyl-L-methionine (SAM). Superoxide can also deprotonate histone N-terminal tail lysines and accelerate the formation of their complexes with acetyl-coenzyme A (AcCoA), the supplier of acetyl groups. In cancer cells ROS enhance DNA methylation causing the silencing of tumor suppressor and antioxidant genes and enhancing the proliferation of cancer cells under condition of oxidative stress. ROS signaling in senescent cells probably causes DNA hypomethylation although there are insufficient data for such proposal.
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Affiliation(s)
- Igor Afanas’ev
- Correspondence should be addressed to: Dr. Igor Afanas’ev, Rua Vitorino Nemesio 48, 6.1, 2050-638, Porto, Portugal.
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254
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Takasaka N, Araya J, Hara H, Ito S, Kobayashi K, Kurita Y, Wakui H, Yoshii Y, Yumino Y, Fujii S, Minagawa S, Tsurushige C, Kojima J, Numata T, Shimizu K, Kawaishi M, Kaneko Y, Kamiya N, Hirano J, Odaka M, Morikawa T, Nishimura SL, Nakayama K, Kuwano K. Autophagy induction by SIRT6 through attenuation of insulin-like growth factor signaling is involved in the regulation of human bronchial epithelial cell senescence. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2014; 192:958-68. [PMID: 24367027 DOI: 10.4049/jimmunol.1302341] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
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.
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Affiliation(s)
- Naoki Takasaka
- Division of Respiratory Diseases, Department of Internal Medicine, Jikei University School of Medicine, Tokyo 105-8461, Japan
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255
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Vlahos R, Bozinovski S. Recent advances in pre-clinical mouse models of COPD. Clin Sci (Lond) 2014; 126:253-65. [PMID: 24144354 PMCID: PMC3878607 DOI: 10.1042/cs20130182] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 07/17/2013] [Accepted: 08/01/2013] [Indexed: 02/06/2023]
Abstract
COPD (chronic obstructive pulmonary disease) is a major incurable global health burden and will become the third largest cause of death in the world by 2020. It is currently believed that an exaggerated inflammatory response to inhaled irritants, in particular cigarette smoke, causes progressive airflow limitation. This inflammation, where macrophages, neutrophils and T-cells are prominent, leads to oxidative stress, emphysema, small airways fibrosis and mucus hypersecretion. The mechanisms and mediators that drive the induction and progression of chronic inflammation, emphysema and altered lung function are poorly understood. Current treatments have limited efficacy in inhibiting chronic inflammation, do not reverse the pathology of disease and fail to modify the factors that initiate and drive the long-term progression of disease. Therefore there is a clear need for new therapies that can prevent the induction and progression of COPD. Animal modelling systems that accurately reflect disease pathophysiology continue to be essential to the development of new therapies. The present review highlights some of the mouse models used to define the cellular, molecular and pathological consequences of cigarette smoke exposure and whether they can be used to predict the efficacy of new therapeutics for COPD.
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Key Words
- acute exacerbations of chronic obstructive pulmonary disease (aecopd)
- chronic obstructive pulmonary disease (copd)
- emphysema
- inflammation
- skeletal muscle wasting
- smoking
- aecopd, acute exacerbations of copd
- bal, bronchoalveolar lavage
- balf, bal fluid
- copd, chronic obstructive pulmonary disease
- gm-csf, granulocyte/macrophage colony-stimulating factor
- gold, global initiative on chronic obstructive lung disease
- gpx, glutathione peroxidase
- hdac, histone deacetylation
- il, interleukin
- ltb4, leukotriene b4
- mapk, mitogen-activated protein kinase
- mcp-1, monocyte chemotactic protein-1
- mmp, matrix metalloproteinase
- ne, neutrophil elastase
- nf-κb, nuclear factor κb
- nrf2, nuclear erythroid-related factor 2
- o2•−, superoxide radical
- onoo−, peroxynitrite
- pde, phosphodiesterase
- pi3k, phosphoinositide 3-kinase
- ros, reactive oxygen species
- rv, rhinovirus
- slpi, secretory leucocyte protease inhibitor
- sod, superoxide dismutase
- tgf-β, transforming growth factor-β
- timp, tissue inhibitor of metalloproteinases
- tnf-α, tumour necrosis factor-α
- v/q, ventilation/perfusion
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Affiliation(s)
- Ross Vlahos
- *Lung Health Research Centre, Department of Pharmacology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Steven Bozinovski
- *Lung Health Research Centre, Department of Pharmacology, University of Melbourne, Parkville, VIC 3010, Australia
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256
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Hubbard BP, Sinclair DA. Small molecule SIRT1 activators for the treatment of aging and age-related diseases. Trends Pharmacol Sci 2014; 35:146-54. [PMID: 24439680 DOI: 10.1016/j.tips.2013.12.004] [Citation(s) in RCA: 420] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 12/09/2013] [Accepted: 12/10/2013] [Indexed: 01/28/2023]
Abstract
Recent studies in mice have identified single molecules that can delay multiple diseases of aging and extend lifespan. In theory, such molecules could prevent dozens of diseases simultaneously, potentially extending healthy years of life. In this review, we discuss recent advances, controversies, opportunities, and challenges surrounding the development of SIRT1 activators, molecules with the potential to delay aging and age-related diseases. Sirtuins comprise a family of NAD⁺-dependent deacylases that are central to the body's response to diet and exercise. New studies indicate that both natural and synthetic sirtuin activating compounds (STACs) work via a common allosteric mechanism to stimulate sirtuin activity, thereby conferring broad health benefits in rodents, primates, and possibly humans. The fact that two-thirds of people in the USA who consume multiple dietary supplements consume resveratrol, a SIRT1 activator, underscores the importance of understanding the biochemical mechanism, physiological effects, and safety of STACs.
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Affiliation(s)
- Basil P Hubbard
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - David A Sinclair
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA; Department of Pharmacology, School of Medical Sciences, The University of New South Wales, Sydney, NSW 2052, Australia.
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257
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Hwang JW, Sundar IK, Yao H, Sellix MT, Rahman I. Circadian clock function is disrupted by environmental tobacco/cigarette smoke, leading to lung inflammation and injury via a SIRT1-BMAL1 pathway. FASEB J 2014; 28:176-94. [PMID: 24025728 PMCID: PMC3868829 DOI: 10.1096/fj.13-232629] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 08/26/2013] [Indexed: 02/03/2023]
Abstract
Patients with obstructive lung diseases display abnormal circadian rhythms in lung function. We determined the mechanism whereby environmental tobacco/cigarette smoke (CS) modulates expression of the core clock gene BMAL1, through Sirtuin1 (SIRT1) deacetylase during lung inflammatory and injurious responses. Adult C57BL6/J and various mice mutant for SIRT1 and BMAL1 were exposed to both chronic (6 mo) and acute (3 and 10 d) CS, and we measured the rhythmic expression of clock genes, circadian rhythms of locomotor activity, lung function, and inflammatory and emphysematous responses in the lungs. CS exposure (100-300 mg/m(3) particulates) altered clock gene expression and reduced locomotor activity by disrupting the central and peripheral clocks and increased lung inflammation, causing emphysema in mice. BMAL1 was acetylated and degraded in the lungs of mice exposed to CS and in patients with chronic obstructive pulmonary disease (COPD), compared with lungs of the nonsmoking controls, linking it mechanistically to CS-induced reduction of SIRT1. Targeted deletion of Bmal1 in lung epithelium augmented inflammation in response to CS, which was not attenuated by the selective SIRT1 activator SRT1720 (EC50=0.16 μM) in these mice. Thus, the circadian clock, specifically the enhancer BMAL1 in epithelium, plays a pivotal role, mediated by SIRT1-dependent BMAL1, in the regulation of CS-induced lung inflammatory and injurious responses.
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Affiliation(s)
- Jae-Woong Hwang
- 2Department of Environmental Medicine, University of Rochester Medical Center, Box 850, 601 Elmwood Avenue, Rochester 14642, NY, USA.
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258
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Engel OG. Reply to the comment by Wendling et al. on the article “Sirt1-deficient mice exhibit an altered cartilage phenotype”, Joint Bone Spine 2013;80:613–20. Joint Bone Spine 2014; 81:104-5. [DOI: 10.1016/j.jbspin.2013.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2013] [Indexed: 10/25/2022]
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259
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Gilels F, Paquette ST, Zhang J, Rahman I, White PM. Mutation of Foxo3 causes adult onset auditory neuropathy and alters cochlear synapse architecture in mice. J Neurosci 2013; 33:18409-24. [PMID: 24259566 PMCID: PMC6618809 DOI: 10.1523/jneurosci.2529-13.2013] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 09/26/2013] [Accepted: 10/12/2013] [Indexed: 11/21/2022] Open
Abstract
Auditory neuropathy is a form of hearing loss in which cochlear inner hair cells fail to correctly encode or transmit acoustic information to the brain. Few genes have been implicated in the adult-onset form of this disease. Here we show that mice lacking the transcription factor Foxo3 have adult onset hearing loss with the hallmark characteristics of auditory neuropathy, namely, elevated auditory thresholds combined with normal outer hair cell function. Using histological techniques, we demonstrate that Foxo3-dependent hearing loss is not due to a loss of cochlear hair cells or spiral ganglion neurons, both of which normally express Foxo3. Moreover, Foxo3-knock-out (KO) inner hair cells do not display reductions in numbers of synapses. Instead, we find that there are subtle structural changes in and surrounding inner hair cells. Confocal microscopy in conjunction with 3D modeling and quantitative analysis show that synaptic localization is altered in Foxo3-KO mice and Myo7a immunoreactivity is reduced. TEM demonstrates apparent afferent degeneration. Strikingly, acoustic stimulation promotes Foxo3 nuclear localization in vivo, implying a connection between cochlear activity and synaptic function maintenance. Together, these findings support a new role for the canonical damage response factor Foxo3 in contributing to the maintenance of auditory synaptic transmission.
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MESH Headings
- Acoustic Stimulation
- Age Factors
- Alcohol Oxidoreductases
- Animals
- Animals, Newborn
- Calcium-Binding Proteins/metabolism
- Co-Repressor Proteins
- Cochlea/growth & development
- Cochlea/metabolism
- Cochlea/pathology
- DNA-Binding Proteins/metabolism
- Disease Models, Animal
- Evoked Potentials, Auditory, Brain Stem/genetics
- Forkhead Box Protein O3
- Forkhead Transcription Factors/genetics
- Forkhead Transcription Factors/metabolism
- Gene Expression Regulation, Developmental/genetics
- Hair Cells, Auditory, Inner/metabolism
- Hair Cells, Auditory, Inner/pathology
- Hair Cells, Auditory, Inner/ultrastructure
- Hearing Loss, Central/genetics
- Hearing Loss, Central/pathology
- Hearing Loss, Central/physiopathology
- Imaging, Three-Dimensional
- Mice
- Mice, Transgenic
- Microscopy, Electron, Transmission
- Mutation/genetics
- Myosin VIIa
- Myosins/metabolism
- Phosphoproteins/metabolism
- Receptors, AMPA/metabolism
- Synapses/genetics
- Synapses/pathology
- Synapses/ultrastructure
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Affiliation(s)
| | | | | | - Irfan Rahman
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
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260
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Yao H, Sundar IK, Gorbunova V, Rahman I. P21-PARP-1 pathway is involved in cigarette smoke-induced lung DNA damage and cellular senescence. PLoS One 2013; 8:e80007. [PMID: 24244594 PMCID: PMC3823706 DOI: 10.1371/journal.pone.0080007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 10/07/2013] [Indexed: 12/20/2022] Open
Abstract
Persistent DNA damage triggers cellular senescence, which may play an important role in the pathogenesis of cigarette smoke (CS)-induced lung diseases. Both p21CDKN1A (p21) and poly(ADP-ribose) polymerase-1 (PARP-1) are involved in DNA damage and repair. However, the role of p21-PARP-1 axis in regulating CS-induced lung DNA damage and cellular senescence remains unknown. We hypothesized that CS causes DNA damage and cellular senescence through a p21-PARP-1 axis. To test this hypothesis, we determined the levels of γH2AX (a marker for DNA double-strand breaks) as well as non-homologous end joining proteins (Ku70 and Ku80) in lungs of mice exposed to CS. We found that the level of γH2AX was increased, whereas the level of Ku70 was reduced in lungs of CS-exposed mice. Furthermore, p21 deletion reduced the level of γH2AX, but augmented the levels of Ku70, Ku80, and PAR in lungs by CS. Administration of PARP-1 inhibitor 3-aminobenzamide increased CS-induced DNA damage, but lowered the levels of Ku70 and Ku80, in lungs of p21 knockout mice. Moreover, 3-aminobenzamide increased senescence-associated β-galactosidase activity, but decreased the expression of proliferating cell nuclear antigen in mouse lungs in response to CS. Interestingly, 3-aminobenzamide treatment had no effect on neutrophil influx into bronchoalveolar lavage fluid by CS. These results demonstrate that the p21-PARP-1 pathway is involved in CS-induced DNA damage and cellular senescence.
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Affiliation(s)
- Hongwei Yao
- Department of Environmental Medicine, Lung Biology and Disease Program, Rochester, New York, United States of America
- * E-mail: (HY); (IR)
| | - Isaac K. Sundar
- Department of Environmental Medicine, Lung Biology and Disease Program, Rochester, New York, United States of America
| | - Vera Gorbunova
- Department of Biology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Irfan Rahman
- Department of Environmental Medicine, Lung Biology and Disease Program, Rochester, New York, United States of America
- * E-mail: (HY); (IR)
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261
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Lam HC, Cloonan SM, Bhashyam AR, Haspel JA, Singh A, Sathirapongsasuti JF, Cervo M, Yao H, Chung AL, Mizumura K, An CH, Shan B, Franks JM, Haley KJ, Owen CA, Tesfaigzi Y, Washko GR, Quackenbush J, Silverman EK, Rahman I, Kim HP, Mahmood A, Biswal SS, Ryter SW, Choi AMK. Histone deacetylase 6-mediated selective autophagy regulates COPD-associated cilia dysfunction. J Clin Invest 2013; 123:5212-30. [PMID: 24200693 DOI: 10.1172/jci69636] [Citation(s) in RCA: 243] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 08/30/2013] [Indexed: 01/05/2023] Open
Abstract
Chronic obstructive pulmonary disease (COPD) involves aberrant airway inflammatory responses to cigarette smoke (CS) that are associated with epithelial cell dysfunction, cilia shortening, and mucociliary clearance disruption. Exposure to CS reduced cilia length and induced autophagy in vivo and in differentiated mouse tracheal epithelial cells (MTECs). Autophagy-impaired (Becn1+/- or Map1lc3B-/-) mice and MTECs resisted CS-induced cilia shortening. Furthermore, CS increased the autophagic turnover of ciliary proteins, indicating that autophagy may regulate cilia homeostasis. We identified cytosolic deacetylase HDAC6 as a critical regulator of autophagy-mediated cilia shortening during CS exposure. Mice bearing an X chromosome deletion of Hdac6 (Hdac6-/Y) and MTECs from these mice had reduced autophagy and were protected from CS-induced cilia shortening. Autophagy-impaired Becn1-/-, Map1lc3B-/-, and Hdac6-/Y mice or mice injected with an HDAC6 inhibitor were protected from CS-induced mucociliary clearance (MCC) disruption. MCC was preserved in mice given the chemical chaperone 4-phenylbutyric acid, but was disrupted in mice lacking the transcription factor NRF2, suggesting that oxidative stress and altered proteostasis contribute to the disruption of MCC. Analysis of human COPD specimens revealed epigenetic deregulation of HDAC6 by hypomethylation and increased protein expression in the airways. We conclude that an autophagy-dependent pathway regulates cilia length during CS exposure and has potential as a therapeutic target for COPD.
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262
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Hardeland R. Melatonin and the theories of aging: a critical appraisal of melatonin's role in antiaging mechanisms. J Pineal Res 2013; 55:325-56. [PMID: 24112071 DOI: 10.1111/jpi.12090] [Citation(s) in RCA: 189] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 08/23/2013] [Indexed: 02/06/2023]
Abstract
The classic theories of aging such as the free radical theory, including its mitochondria-related versions, have largely focused on a few specific processes of senescence. Meanwhile, numerous interconnections have become apparent between age-dependent changes previously thought to proceed more or less independently. Increased damage by free radicals is not only linked to impairments of mitochondrial function, but also to inflammaging as it occurs during immune remodeling and by release of proinflammatory cytokines from mitotically arrested, DNA-damaged cells that exhibit the senescence-associated secretory phenotype (SASP). Among other effects, SASP can cause mutations in stem cells that reduce the capacity for tissue regeneration or, in worst case, lead to cancer stem cells. Oxidative stress has also been shown to promote telomere attrition. Moreover, damage by free radicals is connected to impaired circadian rhythmicity. Another nexus exists between cellular oscillators and metabolic sensing, in particular to the aging-suppressor SIRT1, which acts as an accessory clock protein. Melatonin, being a highly pleiotropic regulator molecule, interacts directly or indirectly with all the processes mentioned. These influences are critically reviewed, with emphasis on data from aged organisms and senescence-accelerated animals. The sometimes-controversial findings obtained either in a nongerontological context or in comparisons of tumor with nontumor cells are discussed in light of evidence obtained in senescent organisms. Although, in mammals, lifetime extension by melatonin has been rarely documented in a fully conclusive way, a support of healthy aging has been observed in rodents and is highly likely in humans.
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Affiliation(s)
- Rüdiger Hardeland
- Johann Friedrich Blumenbach Institute of Zoology and Anthropology, University of Göttingen, Göttingen, Germany
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263
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Zou T, Yang Y, Xia F, Huang A, Gao X, Fang D, Xiong S, Zhang J. Resveratrol Inhibits CD4+ T cell activation by enhancing the expression and activity of Sirt1. PLoS One 2013; 8:e75139. [PMID: 24073240 PMCID: PMC3779207 DOI: 10.1371/journal.pone.0075139] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Accepted: 08/10/2013] [Indexed: 12/15/2022] Open
Abstract
Resveratrol, a natural polyphenol compound, has broad effects on critical events, including inflammation, oxidation, cancer and aging. However, the function and molecular mechanisms of resveratrol on T cell activation are controversial. In the present study, we found that resveratrol significantly inhibits the activation and cytokine production of T cells in vitro and in vivo. Sirt1 expression was up-regulated in resveratrol-treated T cells. Once Sirt1 was down-regulated in the T cells, the resveratrol-induced inhibition of T cell activation noticeably diminished. The acetylation of c-Jun decreased and its translocation was impeded in the resveratrol-treated T cells. The incidence and severity of collagen-induced arthritis in the resveratrol-treated mice were considerably reduced.
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Affiliation(s)
- Ting Zou
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, Jiangsu Province, People’s Republic of China
| | - Yi Yang
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, Jiangsu Province, People’s Republic of China
| | - Fei Xia
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, Jiangsu Province, People’s Republic of China
| | - Anfei Huang
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, Jiangsu Province, People’s Republic of China
| | - Xiaoming Gao
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, Jiangsu Province, People’s Republic of China
| | - Deyu Fang
- Department of Pathology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Sidong Xiong
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, Jiangsu Province, People’s Republic of China
- * E-mail: (JPZ); (SDX)
| | - Jinping Zhang
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, Jiangsu Province, People’s Republic of China
- * E-mail: (JPZ); (SDX)
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Yao H, Hwang JW, Sundar IK, Friedman AE, McBurney MW, Guarente L, Gu W, Kinnula VL, Rahman I. SIRT1 redresses the imbalance of tissue inhibitor of matrix metalloproteinase-1 and matrix metalloproteinase-9 in the development of mouse emphysema and human COPD. Am J Physiol Lung Cell Mol Physiol 2013; 305:L615-24. [PMID: 24039251 DOI: 10.1152/ajplung.00249.2012] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Sirtuin1 (SIRT1), a protein/histone deacetylase, protects against the development of pulmonary emphysema. However, the molecular mechanisms underlying this observation remain elusive. The imbalance of tissue inhibitor of matrix metalloproteinases (TIMPs)/matrix metalloproteinases (MMPs) plays an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD)/emphysema. We hypothesized that SIRT1 protects against emphysema by redressing the imbalance between MMPs and TIMPs. To test this hypothesis, SIRT1-deficient and overexpressing/transgenic mice were exposed to cigarette smoke (CS). The protein level and activity of MMP-9 were increased in lungs of SIRT1-deficient mice exposed to CS compared with wild-type (WT) littermates, and these effects were attenuated by SIRT1 overexpression. SIRT1 deficiency decreased the level of TIMP-1, which was augmented in SIRT1 transgenic mice compared with WT littermates by CS. However, the level of MMP-2, MMP-12, TIMP-2, TIMP-3, or TIMP-4 was not altered by SIRT1 in response to CS exposure. SIRT1 reduction was associated with imbalance of TIMP-1 and MMP-9 in lungs of smokers and COPD patients. Mass spectrometry and immunoprecipitation analyses revealed that TIMP-1 acetylation on specific lysine residues was increased, whereas its interaction with SIRT1 and MMP-9 was reduced in mouse lungs with emphysema, as well as in lungs of smokers and COPD patients. SIRT1 deficiency increased CS-induced TIMP-1 acetylation, and these effects were attenuated by SIRT1 overexpression. These results suggest that SIRT1 protects against COPD/emphysema, in part, via redressing the TIMP-1/MMP-9 imbalance involving TIMP-1 deacetylation. Thus redressing the TIMP-1/MMP-9 imbalance by pharmacological activation of SIRT1 is an attractive approach in the intervention of COPD.
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Affiliation(s)
- Hongwei Yao
- Dept. of Environmental Medicine, Univ. of Rochester Medical Center, Box 850, 601 Elmwood Ave., Rochester, NY 14642.
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265
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McBurney MW, Clark-Knowles KV, Caron AZ, Gray DA. SIRT1 is a Highly Networked Protein That Mediates the Adaptation to Chronic Physiological Stress. Genes Cancer 2013; 4:125-34. [PMID: 24020004 DOI: 10.1177/1947601912474893] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
SIRT1 is a NAD(+)-dependent protein deacetylase that has a very large number of established protein substrates and an equally impressive list of biological functions thought to be regulated by its activity. Perhaps as notable is the remarkable number of points of conflict concerning the role of SIRT1 in biological processes. For example, evidence exists suggesting that SIRT1 is a tumor suppressor, is an oncogene, or has no effect on oncogenesis. Similarly, SIRT1 is variably reported to induce, inhibit, or have no effect on autophagy. We believe that the resolution of many conflicting results is possible by considering recent reports indicating that SIRT1 is an important hub interacting with a complex network of proteins that collectively regulate a wide variety of biological processes including cancer and autophagy. A number of the interacting proteins are themselves hubs that, like SIRT1, utilize intrinsically disordered regions for their promiscuous interactions. Many studies investigating SIRT1 function have been carried out on cell lines carrying undetermined numbers of alterations to the proteins comprising the SIRT1 network or on inbred mouse strains carrying fixed mutations affecting some of these proteins. Thus, the effects of modulating SIRT1 amount and/or activity are importantly determined by the genetic background of the cell (or the inbred strain of mice), and the effects attributed to SIRT1 are synthetic with the background of mutations and epigenetic differences between cells and organisms. Work on mice carrying alterations to the Sirt1 gene suggests that the network in which SIRT1 functions plays an important role in mediating physiological adaptation to various sources of chronic stress such as calorie restriction and calorie overload. Whether the catalytic activity of SIRT1 and the nuclear concentration of the co-factor, NAD(+), are responsible for modulating this activity remains to be determined. However, the effect of modulating SIRT1 activity must be interpreted in the context of the cell or tissue under investigation. Indeed, for SIRT1, we argue that context is everything.
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Affiliation(s)
- Michael W McBurney
- Program in Cancer Therapeutics, Ottawa Hospital Research Institute ; Department of Medicine, University of Ottawa, Ottawa, ON, Canada
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266
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Aging does not enhance experimental cigarette smoke-induced COPD in the mouse. PLoS One 2013; 8:e71410. [PMID: 23936505 PMCID: PMC3732225 DOI: 10.1371/journal.pone.0071410] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 06/29/2013] [Indexed: 11/25/2022] Open
Abstract
It has been proposed that the development of COPD is driven by premature aging/premature senescence of lung parenchyma cells. There are data suggesting that old mice develop a greater inflammatory and lower anti-oxidant response after cigarette smoke compared to young mice, but whether these differences actually translate into greater levels of disease is unknown. We exposed C57Bl/6 female mice to daily cigarette smoke for 6 months starting at age 3 months (Ayoung@) or age 12 months (Aold@), with air-exposed controls. There were no differences in measures of airspace size between the two control groups and cigarette smoke induced exactly the same amount of emphysema in young and old. The severity of smoke-induced small airway remodeling using various measures was identical in both groups. Smoke increased numbers of tissue macrophages and neutrophils and levels of 8-hydroxyguanosine, a marker of oxidant damage, but there were no differences between young and old. Gene expression studies using laser capture microdissected airways and parenchyma overall showed a trend to lower levels in older animals and a somewhat lesser response to cigarette smoke in both airways and parenchyma but the differences were usually not marked. Telomere length was greatest in young control mice and was decreased by both smoking and age. The senescence marker p21Waf1 was equally upregulated by smoke in young and old, but p16INK4a, another senescence marker, was not upregulated at all. We conclude, in this model, animal age does not affect the development of emphysema and small airway remodeling.
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267
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Hwang JW, Yao H, Caito S, Sundar IK, Rahman I. Redox regulation of SIRT1 in inflammation and cellular senescence. Free Radic Biol Med 2013; 61:95-110. [PMID: 23542362 PMCID: PMC3762912 DOI: 10.1016/j.freeradbiomed.2013.03.015] [Citation(s) in RCA: 360] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 12/06/2012] [Accepted: 03/20/2013] [Indexed: 12/31/2022]
Abstract
Sirtuin 1 (SIRT1) regulates inflammation, aging (life span and health span), calorie restriction/energetics, mitochondrial biogenesis, stress resistance, cellular senescence, endothelial functions, apoptosis/autophagy, and circadian rhythms through deacetylation of transcription factors and histones. SIRT1 level and activity are decreased in chronic inflammatory conditions and aging, in which oxidative stress occurs. SIRT1 is regulated by a NAD(+)-dependent DNA repair enzyme, poly(ADP-ribose) polymerase-1 (PARP1), and subsequent NAD(+) depletion by oxidative stress may have consequent effects on inflammatory and stress responses as well as cellular senescence. SIRT1 has been shown to undergo covalent oxidative modifications by cigarette smoke-derived oxidants/aldehydes, leading to posttranslational modifications, inactivation, and protein degradation. Furthermore, oxidant/carbonyl stress-mediated reduction of SIRT1 leads to the loss of its control on acetylation of target proteins including p53, RelA/p65, and FOXO3, thereby enhancing the inflammatory, prosenescent, and apoptotic responses, as well as endothelial dysfunction. In this review, the mechanisms of cigarette smoke/oxidant-mediated redox posttranslational modifications of SIRT1 and its roles in PARP1 and NF-κB activation, and FOXO3 and eNOS regulation, as well as chromatin remodeling/histone modifications during inflammaging, are discussed. Furthermore, we have also discussed various novel ways to activate SIRT1 either directly or indirectly, which may have therapeutic potential in attenuating inflammation and premature senescence involved in chronic lung diseases.
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Affiliation(s)
- Jae-woong Hwang
- Lung Biology and Disease Program, Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Hongwei Yao
- Lung Biology and Disease Program, Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Samuel Caito
- Lung Biology and Disease Program, Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Isaac K Sundar
- Lung Biology and Disease Program, Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Irfan Rahman
- Lung Biology and Disease Program, Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA.
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268
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Ayissi VBO, Ebrahimi A, Schluesenner H. Epigenetic effects of natural polyphenols: a focus on SIRT1-mediated mechanisms. Mol Nutr Food Res 2013; 58:22-32. [PMID: 23881751 DOI: 10.1002/mnfr.201300195] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 05/12/2013] [Accepted: 05/14/2013] [Indexed: 12/21/2022]
Abstract
Polyphenols are a class of natural compounds widely distributed in fruits, vegetables, and plants. They have been reported to possess a wide range of activities in prevention and alleviation of various diseases like cancer, neuroinflammation, diabetes, and aging. Polyphenols are effective against chronic diseases and recent reports indicated strong epigenetic effects of polyphenols. Most of the studies investigating epigenetic effects of natural polyphenols have focused on their beneficial effects in cancer treatment. However, epigenetic defects have been demonstrated in many other diseases as well, and application of polyphenols to modulate the epigenome is becoming an interesting field of research. This review summarizes the effects of natural polyphenols in modulating epigenetic-related enzymes as well as their effect in prevention and treatment of chronic diseases with a focus on SIRT1 modulation. We have also discussed the relation between the structure and function of epigenetic-modifying polyphenols.
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Affiliation(s)
- Vincent B Owona Ayissi
- Division of Immunopathology of the Nervous System, Department of Neuropathology, Institute of Pathology, University of Tübingen, Tübingen, Germany; Laboratory of Pharmacology and Toxicology, University of Yaoundé I, Cameroon
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269
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McGowan SE, McCoy DM. Platelet-derived growth factor-A regulates lung fibroblast S-phase entry through p27(kip1) and FoxO3a. Respir Res 2013; 14:68. [PMID: 23819440 PMCID: PMC3717055 DOI: 10.1186/1465-9921-14-68] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 05/31/2013] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Secondary pulmonary alveolar septal formation requires platelet derived growth factor (PDGF-A) and platelet derived growth factor receptor-alpha (PDGFRα), and their regulation influences alveolar septal areal density and thickness. Insufficient PDGFRα expression in lung fibroblasts (LF) results in failed septation. METHODS Mice in which the endogenous PDGFRα-gene regulates expression of the green fluorescent protein were used to temporally and spatially track PDGFRα-signaling. Transition from the G₁/G₀ to the S-phase of the cell cycle was compared in PDGFRα-expressing and non-expressing LF using flow cytometry. Laser scanning confocal microscopy was used to quantify p27(kip1) and forkhead box "other" 3a (FoxO3a) in the nuclei of alveolar cells from mice bearing the PDGFRα-GFP knock-in, and p27(kip1) in mice with a conditional deletion of PDGFRα-gene function. The effects of PDGF-A on the phosphorylation and the intracellular location of FoxO3a were examined using Western immuoblotting and immunocytochemistry. RESULTS In neonatal mouse lungs, entry of the PDGFRα-expressing LF subpopulation into the S-phase of the cell cycle diminished sooner than in their non-expressing LF counterparts. This preferential diminution was influenced by PDGFRα-mediated signaling, which phosphorylates and promotes cytoplasmic localization of FoxO3a. Comparative observations of LF at different ages during secondary septation and in mice that lack PDGFRα in alveolar LF demonstrated that nuclear localization of the G₁ cyclin-dependent kinase inhibitor p27(kip1) correlated with reduced LF entry into S-phase. CONCLUSIONS Nuclear localization of FoxO3a, an important regulator of p27(kip1) gene-expression, correlates with diminished proliferation of the PDGFRα-expressing LF subpopulation. These mechanisms for diminishing the effects of PDGFRα-mediated signaling likely regulate secondary septal formation and their derangement may contribute to imbalanced fibroblast cell kinetics in parenchymal lung diseases.
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Affiliation(s)
- Stephen E McGowan
- Department of Veterans Affairs Research Service, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
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270
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Vitamin D and chronic obstructive pulmonary disease: hype or reality? THE LANCET RESPIRATORY MEDICINE 2013; 1:804-12. [PMID: 24461760 DOI: 10.1016/s2213-2600(13)70102-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Abundant laboratory findings show the important role vitamin D has in the innate and adaptive immune system. In human beings, observational studies have associated vitamin D deficiency with an increased risk for different inflammatory, infectious, and autoimmune diseases. With regard to chronic obstructive pulmonary disease (COPD), conflicting data have been reported. Most epidemiological studies have been restricted by their design, and larger longitudinal studies of population-based samples and of cohorts with COPD are warranted. An alternative explanation for the discordant results in COPD might be related to the complexity of the intracellular vitamin D signalling pathway, which is not shown in systemic levels of the precursor 25-hydroxyvitamin D. For COPD in particular, we speculate that local downregulation of vitamin D signalling from and beyond the receptor might clarify why pro-inflammatory processes in the airways are not or are insufficiently countered by vitamin D-dependent control mechanisms. In a disease already characterised by glucocorticoid resistance, the potential activation and reactivation of an intrinsic comprehensive system of immune control should attract more attention to design appropriate interventions with promising therapeutic potential.
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271
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Abstract
Aging is characterized by a progressive loss of physiological integrity, leading to impaired function and increased vulnerability to death. This deterioration is the primary risk factor for major human pathologies, including cancer, diabetes, cardiovascular disorders, and neurodegenerative diseases. Aging research has experienced an unprecedented advance over recent years, particularly with the discovery that the rate of aging is controlled, at least to some extent, by genetic pathways and biochemical processes conserved in evolution. This Review enumerates nine tentative hallmarks that represent common denominators of aging in different organisms, with special emphasis on mammalian aging. These hallmarks are: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication. A major challenge is to dissect the interconnectedness between the candidate hallmarks and their relative contributions to aging, with the final goal of identifying pharmaceutical targets to improve human health during aging, with minimal side effects.
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Affiliation(s)
- Carlos López-Otín
- Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Oncología (IUOPA), Universidad de Oviedo, Oviedo, Spain
| | - Maria A. Blasco
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Linda Partridge
- Max Planck Institute for Biology of Ageing, Cologne, Germany
- Institute of Healthy Ageing, Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Manuel Serrano
- Tumor Suppression Group, Molecular Oncology Program, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Guido Kroemer
- INSERM, U848, Villejuif, France
- Metabolomics Platform, Institut Gustave Roussy, Villejuif, France
- Centre de Recherche des Cordeliers, Paris, France
- Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
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272
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Sun L, Li H, Chen J, Dehennaut V, Zhao Y, Yang Y, Iwasaki Y, Kahn-Perles B, Leprince D, Chen Q, Shen A, Xu Y. A SUMOylation-dependent pathway regulates SIRT1 transcription and lung cancer metastasis. J Natl Cancer Inst 2013; 105:887-98. [PMID: 23704280 DOI: 10.1093/jnci/djt118] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Epithelial-to-mesenchymal transition (EMT) plays a pivotal role in lung cancer metastasis. The class III deacetylase sirtuin 1 (SIRT1) possesses both pro- and anticarcinogenic properties. The role of SIRT1 in lung cancer EMT is largely undefined. METHODS The effect of SIRT1 on migration of lung cancer cells was evaluated by wound healing assay in vitro and metastasis assay in nude mice in vivo. Protein expression in human lung cancers and cultured lung cancer cells was assessed by western blotting and immunohistochemistry. Interaction between protein and DNA was measured by chromatin immunoprecipitation assay. SIRT1 promoter activity was determined by reporter assay. RESULTS SIRT1 activation antagonized migration of lung cancer cells by suppressing EMT in vitro. Activation of SIRT1 by resveratrol also statistically significantly hampered (by 68.33%; P < .001, two-sided test) lung cancer cell metastasis in vivo. Hypoxia repressed SIRT1 transcription through promoting the competition between Sp1 and HIC1 on the SIRT1 proximal promoter in a SUMOylation-dependent manner. Disruption of SUMOylation by targeting either Ubc9 or PIASy restored SIRT1 expression in and favored an epithelial-like phenotype of cancer cells, thereby preventing metastasis. Decreased SIRT1 combined with elevated PIASy expression was implicated in more-invasive types of lung cancers in humans. CONCLUSIONS We have identified a novel pathway that links SIRT1 down-regulation to hypoxia-induced EMT in lung cancer cells and may shed light on the development of novel antitumor therapeutics.
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Affiliation(s)
- Lina Sun
- State Key Laboratory of Reproductive Medicine, Department of Pathophysiology, Provincial Key Laboratory of Cardiovascular Disease, Nanjing Medical University, Nanjing, China
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273
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Sundar IK, Yao H, Rahman I. Oxidative stress and chromatin remodeling in chronic obstructive pulmonary disease and smoking-related diseases. Antioxid Redox Signal 2013; 18:1956-71. [PMID: 22978694 PMCID: PMC3624634 DOI: 10.1089/ars.2012.4863] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
SIGNIFICANCE Chronic obstructive pulmonary disease (COPD) is predominantly a tobacco smoke-triggered disease with features of chronic low-grade systemic inflammation and aging (inflammaging) of the lung associated with steroid resistance induced by cigarette smoke (CS)-mediated oxidative stress. Oxidative stress induces various kinase signaling pathways leading to chromatin modifications (histone acetylation/deacetylation and histone methylation/demethylation) in inflammation, senescence, and steroid resistance. RECENT ADVANCES Histone mono-, di-, or tri-methylation at lysine residues result in either gene activation (H3K4, H3K36, and H3K79) or repression (H3K9, H3K27, and H3K20). Cross-talk occurs between various epigenetic marks on histones and DNA methylation. Both CS and oxidants alter histone acetylation/deacetylation and methylation/demethylation leading to enhanced proinflammatory gene expression. Chromatin modifications occur in lungs of patients with COPD. Histone deacetylase 2 (HDAC2) reduction (levels and activity) is associated with steroid resistance in response to oxidative stress. CRITICAL ISSUES Histone modifications are associated with DNA damage/repair and epigenomic instability as well as premature lung aging, which have implications in the pathogenesis of COPD. HDAC2/SIRTUIN1 (SIRT1)-dependent chromatin modifications are associated with DNA damage-induced inflammation and senescence in response to CS-mediated oxidative stress. FUTURE DIRECTIONS Understanding CS/oxidative stress-mediated chromatin modifications and the cross-talk between histone acetylation and methylation will demonstrate the involvement of epigenetic regulation of chromatin remodeling in inflammaging. This will lead to identification of novel epigenetic-based therapies against COPD and other smoking-related lung diseases. Pharmacological activation of HDAC2/SIRT1 or reversal of their oxidative post-translational modifications may offer therapies for treatment of COPD and CS-related diseases based on epigenetic histone modifications.
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Affiliation(s)
- Isaac K Sundar
- Department of Environmental Medicine, Lung Biology and Disease Program, University of Rochester Medical Center, Rochester, New York 14642, USA
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274
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Lee SH, Um SJ, Kim EJ. CBX8 suppresses Sirtinol-induced premature senescence in human breast cancer cells via cooperation with SIRT1. Cancer Lett 2013; 335:397-403. [PMID: 23474493 DOI: 10.1016/j.canlet.2013.02.051] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 02/22/2013] [Accepted: 02/24/2013] [Indexed: 12/14/2022]
Abstract
Stress-induced premature senescence (SIPS) has been implicated in the suppression of carcinogenesis. We identified chromodomain protein 8 (CBX8), a Polycomb group (PcG) protein, as a novel binding partner of SIRT1. The interaction between CBX8 and SIRT1 was demonstrated by immunoprecipitation, GST pull-down, fluorescence microscopy, and cooperation for transcriptional repression. Like SIRT1, CBX8 repressed premature senescence and growth arrest induced by the SIRT1 inhibitor Sirtinol in MCF7 cells, which was reversed by depleting CBX8. CBX8 cooperated with SIRT1 for suppressing p53 acetylation induced by Sirtinol and etoposide/TSA. Upon ectopic expression, CBX8 or SIRT1 repressed the expression of p21(WAF1) by inhibiting p53 binding to the promoter. We provide the first evidence that CBX8 plays a potential role in regulating premature senescence in human breast cancer cells through cooperation with SIRT1.
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Affiliation(s)
- Sang Hyup Lee
- Department of Molecular Biology, BK21 Graduate Program, Dankook University, Yongin-si, Gyeonggi-do 448-701, Republic of Korea
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275
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Morris BJ. Seven sirtuins for seven deadly diseases of aging. Free Radic Biol Med 2013; 56:133-71. [PMID: 23104101 DOI: 10.1016/j.freeradbiomed.2012.10.525] [Citation(s) in RCA: 276] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 08/31/2012] [Accepted: 10/05/2012] [Indexed: 12/14/2022]
Abstract
Sirtuins are a class of NAD(+)-dependent deacetylases having beneficial health effects. This extensive review describes the numerous intracellular actions of the seven mammalian sirtuins, their protein targets, intracellular localization, the pathways they modulate, and their role in common diseases of aging. Selective pharmacological targeting of sirtuins is of current interest in helping to alleviate global disease burden. Since all sirtuins are activated by NAD(+), strategies that boost NAD(+) in cells are of interest. While most is known about SIRT1, the functions of the six other sirtuins are now emerging. Best known is the involvement of sirtuins in helping cells adapt energy output to match energy requirements. SIRT1 and some of the other sirtuins enhance fat metabolism and modulate mitochondrial respiration to optimize energy harvesting. The AMP kinase/SIRT1-PGC-1α-PPAR axis and mitochondrial sirtuins appear pivotal to maintaining mitochondrial function. Downregulation with aging explains much of the pathophysiology that accumulates with aging. Posttranslational modifications of sirtuins and their substrates affect specificity. Although SIRT1 activation seems not to affect life span, activation of some of the other sirtuins might. Since sirtuins are crucial to pathways that counter the decline in health that accompanies aging, pharmacological agents that boost sirtuin activity have clinical potential in treatment of diabetes, cardiovascular disease, dementia, osteoporosis, arthritis, and other conditions. In cancer, however, SIRT1 inhibitors could have therapeutic value. Nutraceuticals such as resveratrol have a multiplicity of actions besides sirtuin activation. Their net health benefit and relative safety may have originated from the ability of animals to survive environmental changes by utilizing these stress resistance chemicals in the diet during evolution. Each sirtuin forms a key hub to the intracellular pathways affected.
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Affiliation(s)
- Brian J Morris
- Basic & Clinical Genomics Laboratory, School of Medical Sciences and Bosch Institute, Building F13, University of Sydney, NSW 2006, Australia.
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276
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Goldklang MP, Marks SM, D'Armiento JM. Second hand smoke and COPD: lessons from animal studies. Front Physiol 2013; 4:30. [PMID: 23450717 PMCID: PMC3583033 DOI: 10.3389/fphys.2013.00030] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Accepted: 02/07/2013] [Indexed: 12/25/2022] Open
Abstract
Exposure to second hand smoke is a major cause of chronic obstructive pulmonary disease (COPD) in the non-smoker. In this review we explore the use of animal smoke exposure models and their insight into disease pathogenesis. The methods of smoke exposure, including exposure delivery systems, are described. Key findings from the acute and chronic smoke exposure models are outlined, including descriptions of the inflammation processes, proteases involved, oxidative stress, and apoptosis. Finally, alternatives to rodent models of lung disease are presented.
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277
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Xiong S, Salazar G, Patrushev N, Ma M, Forouzandeh F, Hilenski L, Alexander RW. Peroxisome proliferator-activated receptor γ coactivator-1α is a central negative regulator of vascular senescence. Arterioscler Thromb Vasc Biol 2013; 33:988-98. [PMID: 23430617 DOI: 10.1161/atvbaha.112.301019] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Cellular senescence influences organismal aging and increases predisposition to age-related diseases, in particular cardiovascular disease, a leading cause of death and disability worldwide. Peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) is a master regulator of mitochondrial biogenesis and function, oxidative stress, and insulin resistance. Senescence is associated with telomere and mitochondrial dysfunction and oxidative stress, implying a potential causal role of PGC-1α in senescence pathogenesis. APPROACH AND RESULTS We generated a PGC-1α(+/-)/apolipoprotein E(-/-) mouse model and showed that PGC-1α deficiency promotes a vascular senescence phenotype that is associated with increased oxidative stress, mitochondrial abnormalities, and reduced telomerase activity. PGC-1α disruption results in reduced expression of the longevity-related deacetylase sirtuin 1 (SIRT1) and the antioxidant catalase, and increased expression of the senescence marker p53 in aortas. Further, angiotensin II, a major hormonal inducer of vascular senescence, induces prolonged lysine acetylation of PGC-1α and releases the PGC-1α-FoxO1 complex from the SIRT1 promoter, thus reducing SIRT1 expression. The phosphorylation-defective mutant PGC-1α S570A is not acetylated, is constitutively active for forkhead box O1-dependent SIRT1 transcription, and prevents angiotensin II-induced senescence. Acetylation of PGC-1α by angiotensin II interrupts the PGC-1α-forkhead box O1-SIRT1 feed-forward signaling circuit leading to SIRT1 and catalase downregulation and vascular senescence. CONCLUSIONS PGC-1α is a primary negative regulator of vascular senescence. Moreover, the central role of posttranslational modification of PGC-1α in regulating angiotensin II-induced vascular senescence may inform development of novel therapeutic strategies for mitigating age-associated diseases, such as atherosclerosis.
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Affiliation(s)
- Shiqin Xiong
- Division of Cardiology, Emory University Hospital, Emory University School of Medicine, Atlanta, GA, USA
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278
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Preyat N, Leo O. Sirtuin deacylases: a molecular link between metabolism and immunity. J Leukoc Biol 2013; 93:669-80. [PMID: 23325925 DOI: 10.1189/jlb.1112557] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Lysine deacetylation by the NAD(+)-dependent family of sirtuins has been recognized as an important post-translational modification regulating a wide range of cellular processes. These lysine deacetylases have attracted much interest based on their ability to promote survival in response to stress. Sirtuins require NAD(+) for their enzymatic activity, suggesting that these enzymes may represent molecular links between cell metabolism and several human disorders, including diabetes and cancer. Inflammation represents a pathological situation with clear connections to metabolism and aging in humans, raising the possibility that sirtuins may also play an important role during a normal and/or a pathological immune response. A growing body of data has confirmed the immunomodulatory properties of sirtuins, although often with contrasting and opposing conclusions. These observations will be summarized herein and the possible strategies that may lead to the development of novel therapeutic approaches to treat inflammation briefly discussed.
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Affiliation(s)
- Nicolas Preyat
- Laboratory of Immunobiology, Institute for Molecular Biology and Medicine, Université Libre de Bruxelles, Gosselies, Belgium
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279
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Decramer M, Janssens W. Chronic obstructive pulmonary disease and comorbidities. THE LANCET RESPIRATORY MEDICINE 2013; 1:73-83. [PMID: 24321806 DOI: 10.1016/s2213-2600(12)70060-7] [Citation(s) in RCA: 192] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Results of epidemiological studies have shown that chronic obstructive pulmonary disease (COPD) is frequently associated with comorbidities, the most serious and prevalent being cardiovascular disease, lung cancer, osteoporosis, muscle weakness, and cachexia. Mechanistically, environmental risk factors such as smoking, unhealthy diet, exacerbations, and physical inactivity or inherent factors such as genetic background and ageing contribute to this association. No convincing evidence has been provided to suggest that treatment of COPD would reduce comorbidities, although some indirect indications are available. Clear evidence that treatment of comorbidities improves COPD is also lacking, although observational studies would suggest such an effect for statins, β blockers, and angiotensin-converting enzyme blockers and receptor antagonists. Large-scale prospective studies are needed. Reduction of common risk factors seems to be the most powerful approach to reduce comorbidities. Whether reduction of so-called spill-over of local inflammation from the lungs or systemic inflammation with inhaled or systemic anti-inflammatory drugs, respectively, would also reduce COPD-related comorbidities is doubtful.
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Affiliation(s)
- Marc Decramer
- Respiratory Division, University of Leuven, Leuven, Belgium.
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280
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Abstract
Autophagy is a process of lysosomal self-degradation that helps to maintain the homeostatic balance between the synthesis, degradation and recycling of cellular proteins and organelles. Autophagy does not simply function as the machinery for supplying amino acids in response to energy demands, it is an adaptive pathway of cytoprotection against cellular stressors, including starvation, reactive oxygen species (ROS), endoplasmic reticulum (ER) stress and microbial infection. Accordingly, autophagy is considered to be the mediator of a variety of cellular processes and cell fates, including cell survival and death, cellular senescence and immune responses. Due to the organ-specific role of gas exchange, various cell types within the lungs are serially exposed to a diverse array of cellular stressors, and growing evidence has revealed the crucial involvement of autophagy in the pathogenic processes underlying pulmonary diseases. We herein review recent findings regarding the role of autophagy in cellular processes and cell fates and summarize the role that autophagy appears to play in the pathogenesis of pulmonary diseases.
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Affiliation(s)
- Jun Araya
- Division of Respiratory Diseases, Department of Internal Medicine, Jikei University School of Medicine, Japan
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281
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Iskandar AR, Liu C, Smith DE, Hu KQ, Choi SW, Ausman LM, Wang XD. β-cryptoxanthin restores nicotine-reduced lung SIRT1 to normal levels and inhibits nicotine-promoted lung tumorigenesis and emphysema in A/J mice. Cancer Prev Res (Phila) 2012; 6:309-20. [PMID: 23275008 DOI: 10.1158/1940-6207.capr-12-0368] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Nicotine, a large constituent of cigarette smoke, is associated with an increased risk of lung cancer, but the data supporting this relationship are inconsistent. Here, we found that nicotine treatment not only induced emphysema but also increased both lung tumor multiplicity and volume in 4-nitrosamino-1-(3-pyridyl)-1-butanone (NNK)-initiated lung cancer in A/J mice. This tumor-promoting effect of nicotine was accompanied by significant reductions in survival probability and lung Sirtuin 1 (SIRT1) expression, which has been proposed as a tumor suppressor. The decreased level of SIRT1 was associated with increased levels of AKT phosphorylation and interleukin (il)-6 mRNA but decreased tumor suppressor p53 and retinoic acid receptor (RAR)-β mRNA levels in the lungs. Using this mouse model, we then determined whether β-cryptoxanthin (BCX), a xanthophyll that is strongly associated with a reduced risk of lung cancer in several cohort studies, can inhibit nicotine-induced emphysema and lung tumorigenesis. We found that BCX supplementation at two different doses was associated with reductions of the nicotine-promoted lung tumor multiplicity and volume, as well as emphysema in mice treated with both NNK and nicotine. Moreover, BCX supplementation restored the nicotine-suppressed expression of lung SIRT1, p53, and RAR-β to that of the control group, increased survival probability, and decreased the levels of lung il-6 mRNA and phosphorylation of AKT. The present study indicates that BCX is a preventive agent against emphysema and lung cancer with SIRT1 as a potential target. In addition, our study establishes a relevant animal lung cancer model for studying tumor growth within emphysematous microenvironments.
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Affiliation(s)
- Anita R Iskandar
- Nutrition and Cancer Biology Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA
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282
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DNA damage due to oxidative stress in Chronic Obstructive Pulmonary Disease (COPD). Int J Mol Sci 2012; 13:16853-64. [PMID: 23222732 PMCID: PMC3546726 DOI: 10.3390/ijms131216853] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 10/31/2012] [Accepted: 11/19/2012] [Indexed: 12/22/2022] Open
Abstract
According to the American Thorasic Society (ATS)/European Respiratory Society (ERS) Statement, chronic obstructive pulmonary disease (COPD) is defined as a preventable and treatable disease with a strong genetic component, characterized by airflow limitation that is not fully reversible, but is usually progressive and associated with an enhanced inflammatory response of the lung to noxious particles or gases. The main features of COPD are chronic inflammation of the airways and progressive destruction of lung parenchyma and alveolar structure. The pathogenesis of COPD is complex due to the interactions of several mechanisms, such as inflammation, proteolytic/antiproteolytic imbalance, oxidative stress, DNA damage, apoptosis, enhanced senescence of the structural cells and defective repair processes. This review focuses on the effects of oxidative DNA damage and the consequent immune responses in COPD. In susceptible individuals, cigarette smoke injures the airway epithelium generating the release of endogenous intracellular molecules or danger-associated molecular patterns from stressed or dying cells. These signals are captured by antigen presenting cells and are transferred to the lymphoid tissue, generating an adaptive immune response and enhancing chronic inflammation.
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283
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Agarwal AR, Zhao L, Sancheti H, Sundar IK, Rahman I, Cadenas E. Short-term cigarette smoke exposure induces reversible changes in energy metabolism and cellular redox status independent of inflammatory responses in mouse lungs. Am J Physiol Lung Cell Mol Physiol 2012; 303:L889-98. [PMID: 23064950 DOI: 10.1152/ajplung.00219.2012] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Cigarette smoking leads to alteration in cellular redox status, a hallmark in the pathogenesis of chronic obstructive pulmonary disease. This study examines the role of cigarette smoke (CS) exposure in the impairment of energy metabolism and, consequently, mitochondrial dysfunction. Male A/J mice were exposed to CS generated by a smoking machine for 4 or 8 wk. A recovery group was exposed to CS for 8 wk and allowed to recover for 2 wk. Acute CS exposure altered lung glucose metabolism, entailing a decrease in the rate of glycolysis and an increase in the pentose phosphate pathway, as evidenced by altered expression and activity of GAPDH and glucose-6-phosphate dehydrogenase, respectively. Impairment of GAPDH was found to be due to glutathionylation of its catalytic site cysteines. Metabolic changes were associated with changes in cellular and mitochondrial redox status, assessed in terms of pyridine nucleotides and glutathione. CS exposure elicited an upregulation of the expression of complexes II, III, IV, and V and of the activity of complexes II, IV, and V. Microarray analysis of gene expression in mouse lungs after exposure to CS for 8 wk revealed upregulation of a group of genes involved in metabolism, electron transfer chain, oxidative phosphorylation, mitochondrial transport and dynamics, and redox regulation. These changes occurred independently of inflammatory responses. These findings have implications for the early onset of alterations in energy and redox metabolism upon acute lung exposure to CS.
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Affiliation(s)
- Amit R Agarwal
- Pharmacology & Pharmaceutical Sciences, School of Pharmacy, Univ. of Southern California, Los Angeles, CA 90089-9121, USA
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284
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Basic VT, Tadele E, Elmabsout AA, Yao H, Rahman I, Sirsjö A, Abdel-Halim SM. Exposure to cigarette smoke induces overexpression of von Hippel-Lindau tumor suppressor in mouse skeletal muscle. Am J Physiol Lung Cell Mol Physiol 2012; 303:L519-27. [PMID: 22842216 DOI: 10.1152/ajplung.00007.2012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cigarette smoke (CS) is a well-established risk factor in the development of chronic obstructive pulmonary disease (COPD). In contrast, the extent to which CS exposure contributes to the development of the systemic manifestations of COPD, such as skeletal muscle dysfunction and wasting, remains largely unknown. Decreased skeletal muscle capillarization has been previously reported in early stages of COPD and might play an important role in the development of COPD-associated skeletal muscle abnormalities. To investigate the effects of chronic CS exposure on skeletal muscle capillarization and exercise tolerance, a mouse model of CS exposure was used. The 129/SvJ mice were exposed to CS for 6 mo, and the expression of putative elements of the hypoxia-angiogenic signaling cascade as well as muscle capillarization were studied. Additionally, functional tests assessing exercise tolerance/endurance were performed in mice. Compared with controls, skeletal muscles from CS-exposed mice exhibited significantly enhanced expression of von Hippel-Lindau tumor suppressor (VHL), ubiquitin-conjugating enzyme E2D1 (UBE2D1), and prolyl hydroxylase-2 (PHD2). In contrast, hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) expression was reduced. Furthermore, reduced muscle fiber cross-sectional area, decreased skeletal muscle capillarization, and reduced exercise tolerance were also observed in CS-exposed animals. Taken together, the current results provide evidence linking chronic CS exposure and induction of VHL expression in skeletal muscles leading toward impaired hypoxia-angiogenesis signal transduction, reduced muscle fiber cross-sectional area, and decreased exercise tolerance.
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285
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Yao H, Rahman I. Role of histone deacetylase 2 in epigenetics and cellular senescence: implications in lung inflammaging and COPD. Am J Physiol Lung Cell Mol Physiol 2012; 303:L557-66. [PMID: 22842217 DOI: 10.1152/ajplung.00175.2012] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Histone deacetylase 2 (HDAC2) is a class I histone deacetylase that regulates various cellular processes, such as cell cycle, senescence, proliferation, differentiation, development, apoptosis, and glucocorticoid function in inhibiting inflammatory response. HDAC2 has been shown to protect against DNA damage response and cellular senescence/premature aging via an epigenetic mechanism in response to oxidative stress. These phenomena are observed in patients with chronic obstructive pulmonary disease (COPD). HDAC2 is posttranslationally modified by oxidative/carbonyl stress imposed by cigarette smoke and oxidants, leading to its reduction via an ubiquitination-proteasome dependent degradation in lungs of patients with COPD. In this perspective, we have discussed the role of HDAC2 posttranslational modifications and its role in regulation of inflammation, histone/DNA epigenetic modifications, DNA damage response, and cellular senescence, particularly in inflammaging, and during the development of COPD. We have also discussed the potential directions for future translational research avenues in modulating lung inflammaging and cellular senescence based on epigenetic chromatin modifications in diseases associated with increased oxidative stress.
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Affiliation(s)
- Hongwei Yao
- Dept. of Environmental Medicine, Lung Biology and Disease Program, Univ. of Rochester Medical Center, Rochester, NY 14642, USA
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286
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Perspectives on translational and therapeutic aspects of SIRT1 in inflammaging and senescence. Biochem Pharmacol 2012; 84:1332-9. [PMID: 22796566 DOI: 10.1016/j.bcp.2012.06.031] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 06/28/2012] [Accepted: 06/29/2012] [Indexed: 02/08/2023]
Abstract
Sirtuin1 (SIRT1), a type III protein deacetylase, is considered as a novel anti-aging protein involved in regulation of cellular senescence/aging and inflammation. SIRT1 level and activity are decreased during lung inflammaging caused by oxidative stress. The mechanism of SIRT1-mediated protection against inflammaging is associated with the regulation of inflammation, premature senescence, telomere attrition, senescence associated secretory phenotype, and DNA damage response. A variety of dietary polyphenols and pharmacological activators are shown to regulate SIRT1 so as to intervene the progression of type 2 diabetes, cancer, cardiovascular diseases, and chronic obstructive pulmonary disease associated with inflammaging. However, recent studies have shown the non-specific regulation of SIRT1 by the aforementioned pharmacological activators and polyphenols. In this perspective, we have briefly discussed the role of SIRT1 in regulation of cellular senescence and its associated secretory phenotype, DNA damage response, particularly in lung inflammaging and during the development of chronic obstructive pulmonary diseases. We have also discussed the potential directions for future translational therapeutic avenues for SIRT1 in modulating lung inflammaging associated with senescence in chronic lung diseases associated with increased oxidative stress.
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