SIRT1, an Antiinflammatory and Antiaging Protein, Is Decreased in Lungs of Patients with Chronic Obstructive Pulmonary Disease

Saravanan, R.; Yang, Se‐Ran; Kinnula, Vuokko L.; Rahman, Irfan

doi:10.1164/rccm.200708-1269oc

Cited by 461 publications

(406 citation statements)

References 48 publications

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“…[21][22][23][24][25][26] Interestingly, Sirt1 expression in the lung is reduced in the elderly who are known to be particularly susceptible to PM-induced cardiopulmonary mortality. 24,33 In this study, we investigated the role of Sirt1 in PM-induced lung coagulation.…”

Section: Introductionmentioning

confidence: 99%

Sirt1 protects against thrombomodulin down-regulation and lung coagulation after particulate matter exposure

Liu

Liang

et al. 2012

Blood

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Exposure to ambient particulate matter (PM) air pollution has been reported to trigger inflammation and thrombosis. However, molecular mechanisms underlying the modulation of coagulation pathways in PM-induced thrombosis remain largely unknown. We report here that Sirt1, a member of class III histone deacetylase, controls lung inflammation and coagulation after PM exposure. Sirt1 knock-out mice exhibited aggravated lung vascular leakage and inflammation after PM exposure, which was correlated with increased NF-B acetylation and activation. Furthermore, Sirt1 knock-out mice were highly susceptible to PM-induced lung coagulation as demonstrated by increased fibrin formation. The increased fibrin formation was associated with reduced tissue factor pathway inhibitor (TFPI) expression and increased plasminogen activator inhibitor-1 (PAI-1) activity in the lungs, thus favoring elevated coagulation and disrupted fibrinolysis responses. Thrombomodulin (TM), a central player of the anticoagulant protein C system, is regulated by Kruppel-like factor 2 (KLF2) at the transcriptional level. IntroductionExposure to ambient particulate matter (PM) air pollution has been associated with impaired pulmonary function and increased cardiovascular disease-related mortality including inflammation and thrombosis. 1-5 Acute exposure to increased ambient fine particulate matter Ͻ 2.5 m in diameter (PM 2.5 ) was estimated to cause the premature deaths of tens of thousands of people each year in the United States. 6 Urban particulate matter (UPM) PM 2.5, one of the major air pollutants closely monitored by the US Environmental Protection Agency (EPA), is a complex mixture of substances that are directly emitted into the air from dust, soot, smoke, and combustion. 6 To protect public health, the EPA issued the current 24-hour PM 2.5 standard at 35 g/m 3 . 6 Despite the enormous health problems caused by PM 2.5 exposure, there have been few studies performed to explore the molecular mechanisms of PM 2.5 -induced lung vascular dysfunction. PM 2.5 can reach deep in the lung to the small airway and alveoli, 6 and directly cause lung inflammation and injury. [7][8][9][10][11][12][13] The pulmonary complications may lead to detrimental effects on other organs, particularly cardiovascular dysfunction such as systemic microvascular dysfunction and thrombosis. 1,2,4,5,13 A recent study demonstrated that short-term UPM exposure triggered the activation of primary hemostasis in healthy mice, with no substantial secondary hemostasis activation, leading to arterial but not venous thrombosis. 5 Whereas another study showed that short-term UPM exposure may cause activation of coagulation responses and fibrin formation in the lung. 14 Tissue factor pathway inhibitor (TFPI) and plasminogen activator inhibitor-1 (PAI-1) play important roles in coagulation and fibrinolysis cascades, respectively. TFPI is an inhibitor of tissue factor (TF)-mediated coagulation responses. 15 PAI-1, on the other hand, is a major regulator of fibrinolysis, which functions by in...

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Section: Introductionmentioning

confidence: 99%

Sirt1 protects against thrombomodulin down-regulation and lung coagulation after particulate matter exposure

Liu

Liang

et al. 2012

Blood

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“…SIRT1, a representative sirtuin, has been shown to be involved in COPD pathogenesis through prevention of stress-induced inflammation and premature cellular senescence (9,10). In terms of the regulation of autophagy, decreased SIRT1 expression in response to CS exposure has been postulated to correspond with increased autophagy activation, resulting in excessive apoptosis and COPD development (11).…”

mentioning

confidence: 99%

Autophagy Induction by SIRT6 through Attenuation of Insulin-like Growth Factor Signaling Is Involved in the Regulation of Human Bronchial Epithelial Cell Senescence

Takasaka

Araya

Hara

et al. 2014

The Journal of Immunology

160

142

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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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“…Sirtuins have been reported to play important roles in gene silencing (17), cell cycle regulation (18,19), metabolism (8, 10 -12, 14, 20 -22), apoptosis (5,23,24), the lifespan-extension effects of calorie restriction (25,26), and circadian rhythms (27)(28)(29)(30). Sirtuins have emerged as therapeutic targets for diseases (31) such as type 2 diabetes (32), neurodegenerative diseases (33,34), inflammation (35), and cancers (36,37).…”

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confidence: 99%

Crystal Structures of Human SIRT3 Displaying Substrate-induced Conformational Changes

Jin

Wei

Jiang

et al. 2009

Journal of Biological Chemistry

181

224

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SIRT3 is a major mitochondrial NAD؉ -dependent protein deacetylase playing important roles in regulating mitochondrial metabolism and energy production and has been linked to the beneficial effects of exercise and caloric restriction. SIRT3 is emerging as a potential therapeutic target to treat metabolic and neurological diseases. We report the first sets of crystal structures of human SIRT3, an apo-structure with no substrate, a structure with a peptide containing acetyl lysine of its natural substrate acetyl-CoA synthetase 2, a reaction intermediate structure trapped by a thioacetyl peptide, and a structure with the dethioacetylated peptide bound. These structures provide insights into the conformational changes induced by the two substrates required for the reaction, the acetylated substrate peptide and NAD ؉ . In addition, the binding study by isothermal titration calorimetry suggests that the acetylated peptide is the first substrate to bind to SIRT3, before NAD ؉ . These structures and biophysical studies provide key insight into the structural and functional relationship of the SIRT3 deacetylation activity.Sirtuins are class III histone deacetylases that couple lysine deacetylation with NAD ϩ hydrolysis and are highly conserved in prokaryotes and eukaryotes (1). Mammals possess seven sirtuins, SIRT1-7, that occupy different subcellular compartments such as the nucleus (SIRT1, -6, -7), cytoplasm (SIRT2), and the mitochondria (SIRT3, -4, and -5) (2). They deacetylate lysines not only on histone substrates (3, 4) but also on nonhistone substrates such as p53 tumor suppressor protein (5), Foxo transcription factors (6, 7), PGC-1␣ (8), ␣-tubulin (9), acetyl-CoA synthetases (10 -12), and glutamate dehydrogenase (13). SIRT4 and SIRT6 have been shown to have ADP-ribosyltransferase activity (14 -16). Sirtuins have been reported to play important roles in gene silencing (17), cell cycle regulation (18,19), metabolism (8, 10 -12, 14, 20 -22), apoptosis (5, 23, 24), the lifespan-extension effects of calorie restriction (25,26), and circadian rhythms (27)(28)(29)(30) (50), and SIRT5 (51). Sirtuins contain a conserved enzymatic core with two domains; that is, a large Rossmann fold domain that binds NAD ϩ and a small domain formed by two insertions of the large domain that binds to a zinc atom. The acetylated peptide substrate binds to the cleft between the two domains. Some of the known structures are apo structures with sirtuin protein alone, whereas others are bound to acetylated peptide substrate and/or NAD ϩ and its analogs. These structures revealed the mechanism of action for the deacetylation activity and substrate specificity.SIRT3 localizes in mitochondria (13, 52-54) and is a major mitochondrial deacetylase. Hyperacetylation of mitochondrial proteins have been observed in SIRT3 knock-out mice (13, 55). Several key enzymes involved in energy production in the mitochondria have been identified as SIRT3 substrates. Acetyl-CoA synthetase 2 (AceCS2) 2 converts acetate into acetyl-CoA in the mitochondria. Deacetyla...

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SIRT1, an Antiinflammatory and Antiaging Protein, Is Decreased in Lungs of Patients with Chronic Obstructive Pulmonary Disease

Cited by 461 publications

References 48 publications

Sirt1 protects against thrombomodulin down-regulation and lung coagulation after particulate matter exposure

Sirt1 protects against thrombomodulin down-regulation and lung coagulation after particulate matter exposure

Autophagy Induction by SIRT6 through Attenuation of Insulin-like Growth Factor Signaling Is Involved in the Regulation of Human Bronchial Epithelial Cell Senescence

Crystal Structures of Human SIRT3 Displaying Substrate-induced Conformational Changes

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