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1.
Exp Parasitol ; 209: 107822, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31863745

RESUMO

Giardia duodenalis is a flagellated unicellular eukaryotic microorganism that commonly causes diarrheal disease throughout the world. Treatment of giardiasis is limited to nitroheterocyclic compounds as metronidazole and benzimidazoles as albendazole, where remarkably treatment failure is relatively common. Consequently, the need for new options to treat this disease is underscored. We predicted by a bioinformatic approach that nicotinamide inhibits Giardia sirtuins by the nicotinamide exchange pathway, and since sirtuins are involved in cell cycle control, they could be related with arrest and decrease of viability. When trophozoites were treated with nicotinamide (NAM), a strong arrest of Giardia trophozoites in G2 phase was observed and at the same time changes in transcriptional expression of sirtuins were produced. Interestingly, the G2 arrest is not related to double-strand breaks, which strengthens the role of sirtuins in the control of the Giardia cell cycle. Results with NAM-treated trophozoites as predicted demonstrate antigiardial effects and thus open new options for the treatment of giardiasis, either with the combination of nicotinamide with another antigiardial drug, or with the design of specific inhibitors for Giardia sirtuins.


Assuntos
Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Giardia lamblia/efeitos dos fármacos , Niacinamida/farmacologia , Sirtuínas/metabolismo , Complexo Vitamínico B/farmacologia , Sequência de Aminoácidos , Giardia lamblia/citologia , Giardia lamblia/genética , Giardia lamblia/metabolismo , Humanos , Alinhamento de Sequência , Sirtuínas/antagonistas & inibidores , Sirtuínas/química , Sirtuínas/genética
2.
J Chem Theory Comput ; 15(12): 6660-6667, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31765138

RESUMO

Sirtuin 5 is a class III histone deacetylase that, unlike its classification, mainly catalyzes desuccinylation and demanoylation reactions. It is an interesting drug target that we use here to test new ideas for calculating reaction pathways of large molecular systems such as enzymes. A major issue with most schemes (e.g., adiabatic mapping) is that the resulting activation barrier height heavily depends on the chosen educt conformation. This makes the selection of the initial structure decisive for the success of the characterization. Here, we apply machine learning to a large number of molecular dynamics frames and potential energy barriers obtained by quantum mechanics/molecular mechanics calculations in order to identify (1) suitable start-conformations for reaction path calculations and (2) structural features relevant for the first step of the desuccinylation reaction catalyzed by Sirtuin 5. The latter generally aids the understanding of reaction mechanisms and important interactions in active centers. Using our novel approach, we found eleven key features that govern the reactivity. We were able to estimate reaction barriers with a mean absolute error of 3.6 kcal/mol and identified reactive configurations.


Assuntos
Aprendizado de Máquina , Sirtuínas/química , Termodinâmica , Humanos , Simulação de Dinâmica Molecular , Conformação Proteica , Teoria Quântica , Sirtuínas/metabolismo
3.
Zhongguo Zhong Yao Za Zhi ; 44(14): 2966-2971, 2019 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-31602841

RESUMO

To study the effects of saikosaponin b2( SS-b2) on inflammatory factors and energy metabolism against lipopolysaccharide/galactosamine( LPS/Gal N) induced acute liver injury in mice. Mice were randomly divided into normal group( equal amount of normal saline),model group( 100 g·kg~(-1) LPS and 400 mg·kg~(-1) Gal N),low,medium,high dose group of SS-b2( SS-b25,10,20 mg·kg~(-1)·d-1) and positive control group( dexamethasone,10 mg·kg~(-1)). All of the groups except for the normal group were treated with LPS/Gal N though intraperitoneally injection to establish the acute liver injury model. The organ indexes were calculated. The levels of serum transaminases( ALT and AST) and the activities of ATPase( Na+-K+-ATPase,Ca2+-Mg2+-ATPase) in liver were detected. The activity of tumor necrosis factor-α( TNF-α),interleukin-1ß( IL-1ß) and interleukin-6( IL-6) were determined by the enzyme-linked immunosorbent assay( ELISA). The contents of lactate dehydrogenase( LDH) in liver were determined by micro-enzyme method. HE staining was used to observe the histopathological changes of the liver. Histochemical method was used to investigate the protein expression of liver lactate dehydrogenase-A( LDH-A). The protein expressions of Sirt-6 and NF-κB in the liver were detected by Western blot. According to the results,compared with the model group,there were significant changes in organ indexes in the high-dose group of SS-b2( P<0. 05). The level of ALT,AST,TNF-α,IL-1ß,IL-6 and the activities of LDH in serum of mice with liver injury were significantly reduced in the medium and high dose groups of SS-b2( P<0. 01). With the increase of the concentration of SS-b2,the range of hepatic lesions and the damage in mice decreased. The activities of Na+-K+-ATPase and Ca2+-Mg2+-ATPase in liver of mice were significantly enhanced in each dose group( P<0. 01). The expression of NF-κB in liver tissues was significantly down-regulated in the medium and high dose group( P<0. 01). Meanwhile,the expression of Sirt-6 protein in the liver of mice with acute liver injury was significantly increased in each dose group( P<0. 01).In summary,SS-b2 has a significant protective effect on LPS/Gal N-induced acute liver injury in mice,which may be related to the down-regulation of NF-κB protein expression and up-regulation of Sirt-6 protein expression to improve inflammatory injury and energy metabolism.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas/tratamento farmacológico , Metabolismo Energético , Inflamação/tratamento farmacológico , Ácido Oleanólico/análogos & derivados , Saponinas/farmacologia , Animais , Citocinas/metabolismo , Galactosamina , Lipopolissacarídeos , Fígado/efeitos dos fármacos , Camundongos , NF-kappa B/metabolismo , Ácido Oleanólico/farmacologia , Distribuição Aleatória , Sirtuínas/metabolismo
4.
Nat Commun ; 10(1): 4273, 2019 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-31537782

RESUMO

Recognition of specific chromatin modifications by distinct structural domains within "reader" proteins plays a critical role in the maintenance of genomic stability. However, the specific mechanisms involved in this process remain unclear. Here we report that the PHD-Bromo tandem domain of tripartite motif-containing 66 (TRIM66) recognizes the unmodified H3R2-H3K4 and acetylated H3K56. The aberrant deletion of Trim66 results in severe DNA damage and genomic instability in embryonic stem cells (ESCs). Moreover, we find that the recognition of histone modification by TRIM66 is critical for DNA damage repair (DDR) in ESCs. TRIM66 recruits Sirt6 to deacetylate H3K56ac, negatively regulating the level of H3K56ac and facilitating the initiation of DDR. Importantly, Trim66-deficient blastocysts also exhibit higher levels of H3K56ac and DNA damage. Collectively, the present findings indicate the vital role of TRIM66 in DDR in ESCs, establishing the relationship between histone readers and maintenance of genomic stability.


Assuntos
Dano ao DNA/genética , Reparo do DNA/genética , Células-Tronco Embrionárias/citologia , Histonas/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Acetilação , Animais , Linhagem Celular , Cromatina/metabolismo , Cristalografia por Raios X , Instabilidade Genômica/genética , Células HEK293 , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Camundongos , Camundongos Knockout , Domínios Proteicos/fisiologia , Sirtuínas/metabolismo
5.
Mol Cell ; 75(4): 683-699.e7, 2019 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-31399344

RESUMO

Transcriptional regulation in eukaryotes occurs at promoter-proximal regions wherein transcriptionally engaged RNA polymerase II (Pol II) pauses before proceeding toward productive elongation. The role of chromatin in pausing remains poorly understood. Here, we demonstrate that the histone deacetylase SIRT6 binds to Pol II and prevents the release of the negative elongation factor (NELF), thus stabilizing Pol II promoter-proximal pausing. Genetic depletion of SIRT6 or its chromatin deficiency upon glucose deprivation causes intragenic enrichment of acetylated histone H3 at lysines 9 (H3K9ac) and 56 (H3K56ac), activation of cyclin-dependent kinase 9 (CDK9)-that phosphorylates NELF and the carboxyl terminal domain of Pol II-and enrichment of the positive transcription elongation factors MYC, BRD4, PAF1, and the super elongation factors AFF4 and ELL2. These events lead to increased expression of genes involved in metabolism, protein synthesis, and embryonic development. Our results identified SIRT6 as a Pol II promoter-proximal pausing-dedicated histone deacetylase.


Assuntos
Regiões Promotoras Genéticas , RNA Polimerase II/metabolismo , Sirtuínas/metabolismo , Elongação da Transcrição Genética , Acetilação , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular , Deleção de Genes , Histonas/genética , Histonas/metabolismo , Humanos , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , RNA Polimerase II/genética , Sirtuínas/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Fatores de Elongação da Transcrição/genética , Fatores de Elongação da Transcrição/metabolismo
6.
Nucleic Acids Res ; 47(17): 9115-9131, 2019 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-31372634

RESUMO

Global protein synthesis is emerging as an important player in the context of aging and age-related diseases. However, the intricate molecular networks that regulate protein synthesis are poorly understood. Here, we report that SIRT6, a nuclear-localized histone deacetylase represses global protein synthesis by transcriptionally regulating mTOR signalling via the transcription factor Sp1, independent of its deacetylase activity. Our results suggest that SIRT6 deficiency increases protein synthesis in mice. Further, multiple lines of in vitro evidence suggest that SIRT6 negatively regulates protein synthesis in a cell-autonomous fashion and independent of its catalytic activity. Mechanistically, SIRT6 binds to the zinc finger DNA binding domain of Sp1 and represses its activity. SIRT6 deficiency increased the occupancy of Sp1 at key mTOR signalling gene promoters resulting in enhanced expression of these genes and activation of the mTOR signalling pathway. Interestingly, inhibition of either mTOR or Sp1 abrogated the increased protein synthesis observed under SIRT6 deficient conditions. Moreover, pharmacological inhibition of mTOR restored cardiac function in muscle-specific SIRT6 knockout mice, which spontaneously develop cardiac hypertrophy. Overall, these findings have unravelled a new layer of regulation of global protein synthesis by SIRT6, which can be potentially targeted to combat aging-associated diseases like cardiac hypertrophy.


Assuntos
Histona Desacetilases/metabolismo , Biossíntese de Proteínas , Sirtuínas/metabolismo , Fator de Transcrição Sp1/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Transcrição Genética , Animais , Cardiomegalia/genética , Regulação da Expressão Gênica , Células HEK293 , Células HeLa , Histona Desacetilases/genética , Humanos , Camundongos , Camundongos Knockout , Regiões Promotoras Genéticas , Transdução de Sinais , Sirtuínas/genética , Fator de Transcrição Sp1/química , Dedos de Zinco
7.
EMBO J ; 38(18): e100948, 2019 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-31418899

RESUMO

As a ubiquitous bacterial secondary messenger, c-di-GMP plays key regulatory roles in processes such as bacterial motility and transcription regulation. CobB is the Sir2 family protein deacetylase that controls energy metabolism, chemotaxis, and DNA supercoiling in many bacteria. Using an Escherichia coli proteome microarray, we found that c-di-GMP strongly binds to CobB. Further, protein deacetylation assays showed that c-di-GMP inhibits the activity of CobB and thereby modulates the biogenesis of acetyl-CoA. Interestingly, we also found that one of the key enzymes directly involved in c-di-GMP production, DgcZ, is a substrate of CobB. Deacetylation of DgcZ by CobB enhances its activity and thus the production of c-di-GMP. Our work establishes a novel negative feedback loop linking c-di-GMP biogenesis and CobB-mediated protein deacetylation.


Assuntos
GMP Cíclico/análogos & derivados , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Fósforo-Oxigênio Liases/metabolismo , Sirtuínas/metabolismo , Acetilcoenzima A/metabolismo , Acetilação , GMP Cíclico/metabolismo , Retroalimentação Fisiológica , Regulação Bacteriana da Expressão Gênica , Análise Serial de Proteínas/métodos , Proteômica/métodos , Sistemas do Segundo Mensageiro
8.
Mol Cell ; 75(4): 807-822.e8, 2019 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-31442424

RESUMO

mTORC2 controls glucose and lipid metabolism, but the mechanisms are unclear. Here, we show that conditionally deleting the essential mTORC2 subunit Rictor in murine brown adipocytes inhibits de novo lipid synthesis, promotes lipid catabolism and thermogenesis, and protects against diet-induced obesity and hepatic steatosis. AKT kinases are the canonical mTORC2 substrates; however, deleting Rictor in brown adipocytes appears to drive lipid catabolism by promoting FoxO1 deacetylation independently of AKT, and in a pathway distinct from its positive role in anabolic lipid synthesis. This facilitates FoxO1 nuclear retention, enhances lipid uptake and lipolysis, and potentiates UCP1 expression. We provide evidence that SIRT6 is the FoxO1 deacetylase suppressed by mTORC2 and show an endogenous interaction between SIRT6 and mTORC2 in both mouse and human cells. Our findings suggest a new paradigm of mTORC2 function filling an important gap in our understanding of this more mysterious mTOR complex.


Assuntos
Adipócitos Marrons/metabolismo , Proteína Forkhead Box O1/metabolismo , Lipólise , Alvo Mecanístico do Complexo 2 de Rapamicina/metabolismo , Sirtuínas/metabolismo , Adipócitos Marrons/citologia , Animais , Proteína Forkhead Box O1/genética , Células HEK293 , Células HeLa , Humanos , Alvo Mecanístico do Complexo 2 de Rapamicina/genética , Camundongos , Camundongos Transgênicos , Proteína Companheira de mTOR Insensível à Rapamicina/genética , Proteína Companheira de mTOR Insensível à Rapamicina/metabolismo , Sirtuínas/genética
9.
Int J Mol Sci ; 20(16)2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31434333

RESUMO

Left ventricular hypertrophy (LVH) can be adaptive, as arising from exercise, or pathological, most commonly when driven by hypertension. The pathophysiology of LVH is consistently associated with an increase in cytochrome P450 (CYP)1B1 and mitogen-activated protein kinases (MAPKs) and a decrease in sirtuins and mitochondria functioning. Treatment is usually targeted to hypertension management, although it is widely accepted that treatment outcomes could be improved with cardiomyocyte hypertrophy targeted interventions. The current article reviews the wide, but disparate, bodies of data pertaining to LVH pathoetiology and pathophysiology, proposing a significant role for variations in the N-acetylserotonin (NAS)/melatonin ratio within mitochondria in driving the biological underpinnings of LVH. Heightened levels of mitochondria CYP1B1 drive the 'backward' conversion of melatonin to NAS, resulting in a loss of the co-operative interactions of melatonin and sirtuin-3 within mitochondria. NAS activates the brain-derived neurotrophic factor receptor, TrkB, leading to raised trophic signalling via cyclic adenosine 3',5'-monophosphate (cAMP)-response element binding protein (CREB) and the MAPKs, which are significantly increased in LVH. The gut microbiome may be intimately linked to how stress and depression associate with LVH and hypertension, with gut microbiome derived butyrate, and other histone deacetylase inhibitors, significant modulators of the melatonergic pathways and LVH more generally. This provides a model of LVH that has significant treatment and research implications.


Assuntos
Citocromo P-450 CYP1B1/metabolismo , Hipertrofia Ventricular Esquerda/metabolismo , Animais , Citocromo P-450 CYP1B1/genética , Microbioma Gastrointestinal/fisiologia , Humanos , Hipertrofia Ventricular Esquerda/fisiopatologia , Melatonina/metabolismo , Mitocôndrias/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Sirtuínas/metabolismo
10.
J Integr Neurosci ; 18(2): 117-126, 2019 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-31321952

RESUMO

It has been well established that mammalian sterile 20-like 1 (MST1) functions as a suppressor via regulating cell progression in many tumors. However, the molecular mechanism of MST1 on regulating glioma progression remains unclear. Here, we discovered that MST1 was robustly down-regulated in glioma tissues and cells. Functional analysis showed that over-expression of MST1 downregulated viability and colony formation and promoted apoptosis of glioma cells. Our results also identified that MST1 positively regulated expression of SIRT6 (Sirtuin 6) via transcriptional factor FOXO3a (Forkhead box O3a). Furthermore, the functional role of MST1 in glioma cell viability (or apoptosis) were significantly reversed after knocking down of SIRT6. Our research indicates that MST1 is a potential biomarker for the prognosis and diagnosis of glioma and provides new direction on the molecular mechanism of glioma progression and development.


Assuntos
Apoptose , Neoplasias Encefálicas/metabolismo , Glioma/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Sirtuínas/metabolismo , Adulto , Biomarcadores Tumorais/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular , Feminino , Proteína Forkhead Box O3/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Regulação para Cima
11.
Eur J Pharmacol ; 858: 172520, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31278893

RESUMO

The metabolic disorder of succinate in myocardial tissue during ischemia-reperfusion can lead to the myocardial oxidative injury. The activation of succinate dehydrogenase (SDH) plays a vital role in the process. Silent information regulator 5 (Sirt5), a nicotinamide adenine dinucleotide (NAD)-dependent desuccinylase, desuccinylates and inactivates SDH thus exerting a protective effect on the myocardium. This research was designed to investigate whether exogenous NAD protects the myocardium from the ischemia-reperfusion-induced oxidative injury through regulating Sirt5-SDH pathway and succinate metabolism. We first found that myocardial total NAD level was remarkably increased with NAD treatment (10 mg/kg) for 14 days. NAD administration significantly decreased the lactate dehydrogenase (LDH) level in coronary leakage, decreased the malondialdehyde (MDA) level and increased the reduced glutathione/oxidized glutathione disulfide ratio (GSH/GSSG) in myocardial tissue. In addition, NAD treatment effectively attenuated the depression of cardiac function in the isolated rat hearts after ischemia-reperfusion. Furthermore, we found that exogenous NAD attenuated the succinate accumulation during ischemia and decreased its depleting rate during reperfusion. We also found that NAD administration had no obvious effects on myocardial Sirt5 and SDH-a expressions. However, the results of immunofluorescence showed that Sirt5 and SDH-a interacted in ischemia-reperfused myocardium. Utilizing co-immunoprecipitation method, we found that NAD administration promoted the Sirt5 and SDH-a interaction and decreased the succinylation level of SDH-a. These results implied that exogenous NAD administration promoted Sirt5-mediated SDH-a desuccinylation and decreased the activity of SDH-a, which attenuated the succinate accumulation during ischemia and its depleting rate during reperfusion and finally alleviated reactive oxygen species generation.


Assuntos
Traumatismo por Reperfusão Miocárdica/metabolismo , NAD/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Sirtuínas/metabolismo , Succinato Desidrogenase/metabolismo , Ácido Succínico/metabolismo , Animais , Masculino , Malondialdeído/metabolismo , Traumatismo por Reperfusão Miocárdica/patologia , Miocárdio/metabolismo , Miocárdio/patologia , NAD/administração & dosagem , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos
12.
Mol Med Rep ; 20(2): 1575-1582, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31257493

RESUMO

Hepatocellular carcinoma (HCC) is the most common type of liver cancer, and exhibits a high mortality rate. Sirtuin (SIRT)6 is a member of the sirtuin family, which may be useful targets in the treatment of tumors. The present study aimed to explore the expression of SIRT6 in numerous HCC cell lines and investigate the role of SIRT6 in the proliferation and apoptosis of the HCC cells, and the underlying mechanisms. Overexpression and silencing of SIRT6 were performed by transfection of Huh­7 cells with synthetic overexpression and small interfering RNA (siRNA) plasmids. Cell proliferation was evaluated using a Cell Counting Kit­8 assay. The apoptosis rate was measured via flow cytometry. Cloning efficiency was assessed using plate clone formation assays. The expression of mRNAs and proteins were determined via reverse transcription­quantitative PCR and western blot analyses, respectively. SIRT6 was overexpressed in Hep3B, Huh­7, MHCC­97H, MHCC­97L, MHCC­LM6, MHCC­LM3, YY­8103 and SK­hep­1 cell lines, compared with MIHA and HL­7702 normal liver cell lines. Overexpression of SIRT6 increased the proliferation of Huh­7 cells, upregulated the expression of Bcl­2 and phosphorylation of extracellular­signal regulated protein kinase (ERK), and decreased the expression of cleaved­caspase­3 and Bcl­2­associated X protein (Bax) in Huh­7 cells. siRNA­mediated silencing of SIRT6 decreased the proliferation and increased the apoptosis of Huh­7 cells, downregulated the expression of Bcl­2 and phosphorylated­ERK, and promoted the expression of cleaved­caspase­3 and Bax. The proliferation of Huh­7 cells was decreased using the ERK1/2 inhibitor U0126. The results suggested that SIRT6 affected the proliferation and apoptosis of HCC cells via the regulation of the ERK1/2 pathway, altering the activation of the intrinsic apoptosis pathway. SIRT6 may be a potential target for the treatment of HCC; however, its role requires further investigation.


Assuntos
Apoptose/genética , Regulação Neoplásica da Expressão Gênica , Hepatócitos/metabolismo , Proteína Quinase 1 Ativada por Mitógeno/genética , Proteína Quinase 3 Ativada por Mitógeno/genética , Sirtuínas/genética , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Células Clonais , Hepatócitos/patologia , Humanos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Transdução de Sinais , Sirtuínas/antagonistas & inibidores , Sirtuínas/metabolismo , Proteína X Associada a bcl-2/genética , Proteína X Associada a bcl-2/metabolismo
13.
J Biochem Mol Toxicol ; 33(9): e22368, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31332900

RESUMO

Exposure to arsenic has been linked to the development of type 2 diabetes though its mechanism of toxicity remains unresolved. In this study berberine (BBR) effects on arsenic-induced sirtuin 3 (Sirt3) modifications in isolated mitochondria from rat pancreas were evaluated and compared with metformin (MET). With arsenic, mitochondrial reactive oxygen species (ROS), oxidative stress, and insulin resistance were obtained higher than control. From our results and in the presence of arsenic trioxide, insulin resistance and Sirt3 levels were found to be predominantly elevated that could be the result of compensating mechanisms. Apparently, BBR and MET recruit both direct (as an antioxidant) and indirect mechanisms (Sirt3 content) to deal with arsenic trioxide toxicity. Metformin compared with BBR exhibited a less significant effect on ROS levels and since its direct antioxidant property is minor, depressed the ROS level mainly through the Sirt3 modification.


Assuntos
Arsênico/farmacologia , Berberina/farmacologia , Hipoglicemiantes/farmacologia , Metformina/farmacologia , Mitocôndrias/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Pâncreas/efeitos dos fármacos , Pâncreas/metabolismo , Sirtuínas/metabolismo , Animais , Mitocôndrias/metabolismo , Ratos
14.
Eur J Pharmacol ; 859: 172516, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31265839

RESUMO

Angiotensin II (Ang II) is a vasoactive peptide that elevates arterial blood pressure and leads to hypertension. Ang II has been reported to induce endothelial dysfunction by induction of apoptosis and oxidative stress in vascular endothelial cells. Sirtuin6 (SIRT6) has emerged as a critical regulator for modulating Ang II-induced injury of the cardiovascular system. However, little is known about the role of SIRT6 in regulating Ang II-induced injury in vascular endothelial cells. Here, our results showed that SIRT6 expression was decreased in vascular endothelial cells exposed to Ang II. This was accompanied by decreased cell viabilities as well as increased apoptosis and the production of reactive oxygen species. Functional experiments showed that the overexpression of SIRT6 significantly prohibited Ang II-induced apoptosis and reactive oxygen species generation, while silencing SIRT6 resulted in the opposite effect. Notably, our results showed that overexpression of SIRT6 resulted in a significant increase in the nuclear expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and upregulated the expression of the Nrf2 target gene in vascular endothelial cells exposed to Ang II. Moreover, knockdown of Nrf2 significantly blocked the SIRT6-mediated protection effect against Ang II-induced apoptosis and reactive oxygen species generation. Taken together, these results demonstrate that SIRT6 overexpression alleviates Ang II-induced apoptosis and oxidative stress in vascular endothelial cells by promoting Nrf2 antioxidant signaling. Our study suggests that SIRT6 may serve as a potential therapeutic target for treating hypertension associated with endothelial dysfunction.


Assuntos
Angiotensina II/farmacologia , Elementos de Resposta Antioxidante/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Células Endoteliais/citologia , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Sirtuínas/metabolismo , Linhagem Celular , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Humanos , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Sirtuínas/genética
15.
Oxid Med Cell Longev ; 2019: 3187972, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31285783

RESUMO

Mastitis has severely affected the cattle industry worldwide and has resulted in decreased dairy production and cattle reproduction. Although prevention and treatment methods have been implemented for decades, cattle mastitis is still an intractable disease. Sirtuin 7 (SIRT7) is an NAD+-dependent deacetylase that is involved in various biological processes, including ribosomal RNA synthesis and protein synthesis, DNA damage response, metabolism, and tumorigenesis. However, whether SIRT7 participates in inflammation remains unknown. Our results revealed that SIRT7 is downregulated in tissue samples from mastitic cattle. Therefore, we isolated dairy cow mammary epithelial cells (DCMECs) from breast tissues and developed an in vitro model of lipopolysaccharide- (LPS-) induced inflammation to examine SIRT7 function and its potential role in inflammation. We showed that SIRT7 was significantly downregulated in LPS-treated DCMECs. SIRT7 knockdown significantly increased the LPS-stimulated production of inflammatory mediators, like reactive oxygen and nitric oxide, and upregulated TAB1 and TLR4. In addition, SIRT7 knockdown significantly increased the phosphorylation of TAK1 and NF-κBp65 in LPS-treated DCMECs. Moreover, SIRT7 knockdown promoted the translocation of NF-κBp-p65 to the cell nucleus and then increased the secretion of inflammatory cytokines (IL-1ß and IL-6). In contrast, SIRT7 overexpression had the opposite effects when compared to SIRT7 knockdown in LPS-treated DCMECs. In addition, SIRT7 overexpression attenuated LPS-induced DCMEC apoptosis. Taken together, our results indicate that SIRT7 can suppress LPS-induced inflammation and apoptosis via the NF-κB signaling pathway. Therefore, SIRT7 may be considered as a potential pharmacological target for clinical mastitis therapy.


Assuntos
Inflamação/induzido quimicamente , Inflamação/metabolismo , Lipopolissacarídeos/toxicidade , Sirtuínas/metabolismo , Animais , Bovinos , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Feminino , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Glândulas Mamárias Animais/metabolismo , Mastite/metabolismo , NF-kappa B/metabolismo , Óxido Nítrico/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Sirtuínas/genética
16.
Life Sci ; 231: 116558, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31194993

RESUMO

AIMS: We aimed to explore the role of SIRT6 in Insulin resistance (IR). We are the first to investigate on this crucial relationship in an obese mouse model fed on a high-fat diet (HFD) and an IR model based on the mature 3T3-L1-derived adipocytes. MAIN METHODS: Western blotting (WB) and qPCR analysis were performed to evaluate the SIRT6 protein and mRNA expressions in HFD mice as well as IR cells. Injection of adenovirus encoding SIRT6 gene in HFD mice and transfection of pcDNA3-SIRT6 in IR cells increased the glucose uptake levels and insulin sensitivity. KEY FINDINGS: The positive regulatory effects of SIRT6 on transient receptor potential vallinoid 1 (TRPV1) in IR cells were confirmed by a mechanistic investigation at both protein and mRNA levels. Further, the overexpression of SIRT6 was found to activate the TRPV1/Calcitonin gene-related peptide (CGRP) signaling and upregulate the glucose transporter (GLUT) expression at protein and mRNA levels. Additionally, administration of the TRPV1 antagonist, SB-705498 repressed the insulin sensitivity upregulated by SIRT6 overexpression accompanied with the inhibition of CGRP and decrease in GLUT proportions. The results also showed that TRPV1 agonist, Capsaicin boosted the SIRT6-induced glucose uptake, CGRP production, and GLUT4 levels. SIGNIFICANCE: Overall, SIRT6 was concluded to be involved in the TRPV1-CGRP-GLUT4 signaling axis thus leading to increased glucose uptake and decreased IR in HFD mice and 3T3-L1 adipocytes. Therefore, in terms of obesity and diabetes, SIRT6 is a novel candidate for treating IR.


Assuntos
Glucose/metabolismo , Resistência à Insulina/fisiologia , Sirtuínas/metabolismo , Células 3T3-L1 , Adipócitos/metabolismo , Animais , Transporte Biológico , Peptídeo Relacionado com Gene de Calcitonina/metabolismo , Dieta Hiperlipídica , Modelos Animais de Doenças , Transportador de Glucose Tipo 4/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Terapia de Alvo Molecular , Obesidade/metabolismo , Canais de Cátion TRPV/metabolismo
17.
Med Sci Monit ; 25: 4137-4148, 2019 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-31158122

RESUMO

BACKGROUND Resveratrol has been shown to possess beneficial activities including antioxidant, anti-inflammatory, and cardioprotective effects through activating a nicotinamide adenine dinucleotide (NAD)-dependent histone deacetylase family member sirtuin-1 (SIRT1) protein. The current study was undertaken to investigate the role of sirtuin family members (SIRT1-SIRT7) on the anti-inflammation activities of resveratrol in endothelial cells. MATERIAL AND METHODS Primary human umbilical vein endothelial cells (HUVECs) were pretreated with resveratrol before tumor necrosis factor (TNF)-alpha (10-20 µg/L) stimulation. Cell viability was measured using the Cell Counting Kit-8 method. Total RNA was extracted after different treatments and the NimbleGen Human 12×135K Gene Expression Array was applied to screen and analyze SIRTs expression. Quantitative real-time polymerase chain reaction and western blot were applied to verify the results of the gene expression microarrays. Reactive oxygen species (ROS) production was examined using flow cytometry analysis. RESULTS Microarray analysis showed that the expressions of SIRT1, SIRT2, SIRT3, SIRT5, SIRT6, and SIRT7 showed the tendency to increase while SIRT4 showed the tendency to decrease. SIRT1, SIRT2, SIRT5, and SIRT7 gene expression could be upregulated by pretreatment with resveratrol compared with TNF-alpha alone while there were no obvious differences of SIRT3, SIRT4, and SIRT6 expressions observed in TNF-alpha alone treated cells and resveratrol-TNF-alpha co-treated cells. Interestingly, SIRT1, SIRT2, SIRT3, SIRT4, and SIRT5 siRNA could reverse the effect of resveratrol on ROS production; SIRT1 and SIRT5 siRNA could significantly increase CD40 expression inhibited by resveratrol in TNF-a treated cells. CONCLUSIONS Our results suggest that resveratrol inhibiting oxidative stress production is associated with SIRT1, SIRT2, SIRT3, SIRT4, and SIRT5 pathways; attenuating CD40 expression was only associated with SIRT1 and SIRT5 pathways in TNF-alpha-induced endothelial cells injury.


Assuntos
Resveratrol/farmacologia , Sirtuínas/metabolismo , Sirtuínas/farmacologia , Antioxidantes , Células Cultivadas , China , Expressão Gênica , Regulação da Expressão Gênica/genética , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Inflamação , Mitocôndrias/genética , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Estresse Oxidativo , RNA Interferente Pequeno/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Sirtuínas/genética , Fator de Necrose Tumoral alfa/metabolismo
18.
Int J Mol Sci ; 20(11)2019 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-31163574

RESUMO

The sirtuins form a family of evolutionarily conserved nicotinamide adenine dinucleotide (NAD)-dependent deacetylases. Seven sirtuins (SIRT1-SIRT7) have been described in mammals, with specific intracellular localization and biological functions associated with mitochondrial energy homeostasis, antioxidant activity, proliferation and DNA repair. Physical exercise affects the expression of sirtuin in skeletal muscle, regulating changes in mitochondrial biogenesis, oxidative metabolism and the cellular antioxidant system. In this context, sirtuin 1 and sirtuin 3 have been the most studied. This review focuses on the effects of different types of exercise on these sirtuins, the molecular pathways involved and the biological effect that is caused mainly in healthy subjects. The reported findings suggest that an acute load of exercise activates SIRT1, which in turn activates biogenesis and mitochondrial oxidative capacity. Additionally, several sessions of exercise (training) activates SIRT1 and also SIRT3 that, together with the biogenesis and mitochondrial oxidative function, jointly activate ATP production and the mitochondrial antioxidant function.


Assuntos
Exercício , Mitocôndrias Musculares/genética , Mitocôndrias Musculares/metabolismo , Músculo Esquelético/fisiologia , Sirtuínas/genética , Sirtuínas/metabolismo , Animais , Biomarcadores , Metabolismo Energético , Regulação da Expressão Gênica , Humanos , Transdução de Sinais
19.
J Physiol Pharmacol ; 70(1)2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31172974

RESUMO

Within the mammalian reproductive system sirtuin 1 and 6 (SIRT1, SIRT6) are considered to contribute to steroid hormone signaling and control of reproductive physiology. Therefore, the specific question is whether and how a commonly used dicarboximide fungicide with antiandrogenic activity, vinclozolin (Vnz) alters SIRT1 and SIRT6 expression and whether both investigated sirtuins positively affect survival of the follicles after vinclozolin exposure. Immunocytochemistry and immunohistochemistry were performed to localize SIRT1 and SIRT6 expression in cultured granulosa cells (GCs; 48 hours) and whole ovarian follicles (24 hours) after treatment with two androgens, testosterone (T; 10-7 M) and dihydrotestosterone (DHT; 10-7 M), and an antiandrogen, Vnz (1.4 x 10-5 M), separately and in combinations. Granulosal and follicular mRNA and protein expression of both sirtuins was also investigated by real-time PCR and Western blot. In addition, their concentration and activity was studied by immunoenzymatic and fluorescence assays. Our observations: (1) demonstrate the presence of both investigated sirtuins in ovarian cells, (2) show their potential involvement in the control of follicular atresia because of increased SIRT1/SIRT6 expression and SIRT1 activity after exposure to Vnz, (3) represent the first data on the interrelationships between sirtuins and androgens in porcine ovarian cells. Based on these findings and our previous results we can conclude, that SIRT1 and SIRT6 do not exert the protective effects in ovarian follicles after vinclozolin exposure. These novel data on the role of SIRT1/SIRT6 in porcine ovarian follicles shows that in the presence of the investigated fungicide, sirtuins are upregulated, which can induce apoptosis of follicular cells. Furthermore the androgen receptor sensitivity to ligands, especially environmental ones (for example: vinclozolin) might be directly linked with the mechanism of action of both investigated sirtuins in the porcine ovary, which requires further investigation.


Assuntos
Antagonistas de Androgênios/farmacologia , Ovário/efeitos dos fármacos , Oxazóis/farmacologia , Sirtuínas/metabolismo , Androgênios/farmacologia , Animais , Di-Hidrotestosterona/farmacologia , Feminino , Ovário/metabolismo , Sirtuínas/genética , Suínos , Testosterona/farmacologia
20.
J Exp Clin Cancer Res ; 38(1): 252, 2019 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-31196136

RESUMO

BACKGROUND: Optimal therapeutic strategies for hepatocellular carcinoma (HCC) patients are still challenging due to the high recurrence rate after surgical resection and chemotherapy resistance. Growing evidence shows that genetic and epigenetic alterations are involved in HCC progression and resistance to therapy, however the molecular mechanisms underlying resistance to therapy have not been fully understood. METHODS: Expression of SIRT7 in 17 paired paraffin-embedded HCC tissues and adjacent nontumoral liver tissues was examined by immunohistochemistry and Western blot. The mRNA expression of SIRT7 in 20 paired frozen HCC tissues and adjacent nontumoral liver tissues was analyzed by quantitative RT-PCR. The biologic consequences of overexpression and knockdown of SIRT7 in HCC therapy sensitivity were studied in vitro and in vivo. Interaction between SIRT7 and p53 were studied in HCC cell lines. RESULTS: SIRT7 expression was frequently upregulated in clinical HCC samples, and its expression was highly associated with TACE-resistance and poor survival (P = 0.008.) Depletion of SIRT7 from multiple liver cancer cell lines significantly increased doxorubicin toxicity while overexpression of SIRT7 largely abolished doxorubicin induced apoptosis. At the molecular level, we observed that SIRT7 interacts with and induces deacetylation of p53 at lysines 320 and 373. Deacetylated p53 showed significantly less affinity for the NOXA promoter and its transcription. In mouse xenografts, SIRT7 suppression increased doxorubicin induced p53 activation, inhibited tumor growth and induced apoptosis. CONCLUSION: The newly identified SIRT7-p53-NOXA axis partially illustrates the molecular mechanism of HCC resistance to therapy and represents a novel potential therapeutic target for HCC treatment.


Assuntos
Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Transdução de Sinais , Sirtuínas/genética , Proteína Supressora de Tumor p53/genética , Idoso , Animais , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/terapia , Morte Celular/genética , Linhagem Celular Tumoral , Proliferação de Células/genética , Modelos Animais de Doenças , Doxorrubicina/farmacologia , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Humanos , Imuno-Histoquímica , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/terapia , Masculino , Camundongos , Pessoa de Meia-Idade , Gradação de Tumores , Estadiamento de Neoplasias , Ligação Proteica , Sirtuínas/metabolismo , Proteína Supressora de Tumor p53/metabolismo
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