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1.
Clin Oral Investig ; 27(12): 7407-7415, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37851128

RESUMO

OBJECTIVE: Sirtuin6 plays an important role in the regulation of inflammation, homeostasis, and apoptosis, and it has anti-inflammatory effects on several diseases. Lipoxin A4 is a pro-resolving lipid mediator of inflammation and inhibits hypoxia-induced apoptosis and oxidative stress. Considering that Lipoxin A4 and Sirtuin6 have protective effects on inflammatory diseases, the aim of this study is to determine the possible roles of these molecules on periodontitis inflammation in saliva and serum and to reveal the relationship of these data with clinical periodontal parameters. MATERIAL AND METHODS: A total of 20 stage III/grade B periodontitis and 20 periodontally healthy subjects were included in this cross-sectional study (all never smokers and systemically healthy). Clinical periodontal parameters (plaque index, probing pocket depth, bleeding on probing, clinical attachment loss) were recorded. Saliva and serum levels of Sirtuin6 and Lipoxin A4 were analyzed by enzyme-linked immunosorbent assay. RESULTS: Serum Sirtuin6 and saliva Lipoxin A4 levels were significantly lower in the periodontitis group than the control group (respectively, p = 0.0098, p = 0.0008). There were negative correlations between all periodontal clinical parameters and saliva Lipoxin A4 level (p < 0.05) and between probing pocket depth, clinical attachment loss, and serum and saliva Sirtuin6 levels (respectively, r = - 0.465 and r = - 0.473, p < 0.05). CONCLUSIONS: Decreased levels of serum Sirtuin6 and saliva Lipoxin A4 in periodontitis patients and their correlation with clinical periodontal parameters suggest that serum Sirtuin6 and saliva Lipoxin A4 may be related with periodontal inflammation. CLINICAL RELEVANCE: Scientific rationale for the study: Sirtuin6 is one of seven members of the family of NAD + dependent protein that played an important role in the regulation of inflammation, energy metabolism, homeostasis, and apoptosis. Sirtuin6 is associated with the pathogenesis of several diseases. Lipoxin A4 is a lipid mediator that inhibits hypoxia-induced apoptosis and oxidative stress, and it has an active role in the resolution of periodontal inflammation. No studies that investigated the potential role Sirtuin6 and its relationship with inflammation resolution and apoptosis mechanisms in severe periodontitis patients. PRINCIPAL FINDINGS: the serum Sirtuin6 and saliva Lipoxin A4 levels were significantly lower and negatively correlated with clinical periodontal parameters in the patients with periodontitis than the healthy controls. PRACTICAL IMPLICATIONS: this study shows that serum Sirtuin6 and saliva Lipoxin A4 may be candidate biomarkers related with periodontal inflammation and estimating to periodontal status. CLINICAL TRIAL REGISTRATION: NCT05417061.


Assuntos
Periodontite Crônica , Lipoxinas , Periodontite , Sirtuínas , Humanos , Periodontite Crônica/metabolismo , Estudos Transversais , Hipóxia/metabolismo , Inflamação/metabolismo , Periodontite/metabolismo , Saliva/química , Saliva/metabolismo , Sirtuínas/química
2.
Angew Chem Int Ed Engl ; 62(49): e202314597, 2023 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-37873919

RESUMO

The sirtuins are NAD+ -dependent lysine deacylases, comprising seven isoforms (SIRT1-7) in humans, which are involved in the regulation of a plethora of biological processes, including gene expression and metabolism. The sirtuins share a common hydrolytic mechanism but display preferences for different ϵ-N-acyllysine substrates. SIRT7 deacetylates targets in nuclei and nucleoli but remains one of the lesser studied of the seven isoforms, in part due to a lack of chemical tools to specifically probe SIRT7 activity. Here we expressed SIRT7 and, using small-angle X-ray scattering, reveal SIRT7 to be a monomeric enzyme with a low degree of globular flexibility in solution. We developed a fluorogenic assay for investigation of the substrate preferences of SIRT7 and to evaluate compounds that modulate its activity. We report several mechanism-based SIRT7 inhibitors as well as de novo cyclic peptide inhibitors selected from mRNA-display library screening that exhibit selectivity for SIRT7 over other sirtuin isoforms, stabilize SIRT7 in cells, and cause an increase in the acetylation of H3 K18.


Assuntos
Sirtuína 1 , Sirtuínas , Humanos , Sirtuína 1/metabolismo , Sirtuínas/química , Acetilação , Hidrólise , Isoformas de Proteínas/metabolismo
3.
J Biol Chem ; 299(11): 105339, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37838168

RESUMO

Sirtuins are a group of NAD+-dependent deacylases that conserved in three domains of life and comprehensively involved in the regulation of gene transcription, chromosome segregation, RNA splicing, apoptosis, and aging. Previous studies in mammalian cells have revealed that sirtuins not only exist as multiple copies, but also show distinct deacylase activities in addition to deacetylation. However, the understanding of sirtuin zymographs in other organisms with respect to molecular evolution remains at an early stage. Here, we systematically analyze the sirtuin activities in representative species from archaea, bacteria, and eukaryotes, using both the HPLC assay and a 7-amino-4-methylcoumarin-based fluorogenic method. Global profiling suggests that the deacylase activities of sirtuins could be divided into three categories and reveals undifferentiated zymographs of class III sirtuins, especially for those from bacteria and archaea. Nevertheless, initial differentiation of enzymatic activity was also observed for the class III sirtuins at both paralog and ortholog levels. Further phylogenetic analyses support a divergent evolution of sirtuin that may originate from class III sirtuins. Together, this work demonstrates a comprehensive panorama of sirtuin zymographs and provides new insights into the cellular specific regulation and molecular evolution of sirtuins.


Assuntos
Evolução Molecular , Sirtuínas , Animais , Bactérias , Filogenia , Sirtuínas/química , Archaea
4.
Curr Opin Struct Biol ; 82: 102666, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37542908

RESUMO

Sirtuins are NAD+-dependent protein lysine deacylases and mono-ADP-ribosylases whose activity regulates different pathways, including DNA damage repair, cell survival and metabolism, reactive oxygen species (ROS) detoxification, inflammation, cardiac function, and neuronal signaling. Considering the beneficial effects of specific sirtuin isoforms on health and lifespan, the past two decades have seen a mounting interest in the development of sirtuin activators. The availability of enzyme-activator co-crystal structures has proven significant throughout the years for elucidating the mechanisms of action of activators and designing more potent and selective molecules. In this review, we highlight the most interesting examples of sirtuin activators and provide comprehensive coverage of the role that structural biology played in their discovery and characterization.


Assuntos
Sirtuínas , Sirtuínas/química , Sirtuínas/metabolismo , Ativadores de Enzimas , Isoformas de Proteínas , Biologia
5.
Genomics Proteomics Bioinformatics ; 21(1): 177-189, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-35278714

RESUMO

Prostate cancer (PCa) is the most commonly diagnosed genital cancer in men worldwide. Around 80% of the patients who developed advanced PCa suffered from bone metastasis, with a sharp drop in the survival rate. Despite great efforts, the detailed mechanisms underlying castration-resistant PCa (CRPC) remain unclear. Sirtuin 5 (SIRT5), an NAD+-dependent desuccinylase, is hypothesized to be a key regulator of various cancers. However, compared to other SIRTs, the role of SIRT5 in cancer has not been extensively studied. Here, we revealed significantly decreased SIRT5 levels in aggressive PCa cells relative to the PCa stages. The correlation between the decrease in the SIRT5 level and the patient's reduced survival rate was also confirmed. Using quantitative global succinylome analysis, we characterized a significant increase in the succinylation at lysine 118 (K118su) of lactate dehydrogenase A (LDHA), which plays a role in increasing LDH activity. As a substrate of SIRT5, LDHA-K118su significantly increased the migration and invasion of PCa cells and LDH activity in PCa patients. This study reveals the reduction of SIRT5 protein expression and LDHA-K118su as a novel mechanism involved in PCa progression, which could serve as a new target to prevent CPRC progression for PCa treatment.


Assuntos
Neoplasias da Próstata , Sirtuínas , Humanos , Masculino , Lactato Desidrogenase 5 , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Sirtuínas/genética , Sirtuínas/química , Sirtuínas/metabolismo
6.
Plant Physiol Biochem ; 194: 236-245, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36436414

RESUMO

Sirtuins are part of a gene family of NAD-dependent deacylases that act on histone and non-histone proteins and control a variety of activities in all living organisms. Their roles are mainly related to energy metabolism and include lifetime regulation, DNA repair, stress resistance, and proliferation. A large amount of knowledge concerning animal sirtuins is available, but data about their plant counterparts are scarce. Plants possess few sirtuins that have, like in animals, a recognized role in stress defense and metabolism regulation. However, engagement in proliferation control, which has been demonstrated for mammalian sirtuins, has not been reported for plant sirtuins so far. In this work, srt1 and srt2 Arabidopsis mutant seedlings have been used to evaluate in vivo the role of sirtuins in cell proliferation and regulation of glutamate dehydrogenase, an enzyme demonstrated to be involved in the control of cell cycle in SIRT4-defective human cells. Moreover, bioinformatic analyses have been performed to elucidate sequence, structure, and function relationships between Arabidopsis sirtuins and between each of them and the closest mammalian homolog. We found that cell proliferation and GDH activity are higher in mutant seedlings, suggesting that both sirtuins exert a physiological inhibitory role in these processes. In addition, mutant seedlings show plant growth and root system improvement, in line with metabolic data. Our data also indicate that utilization of an easy to manipulate organism, such as Arabidopsis plant, can help to shed light on the molecular mechanisms underlying the function of genes present in interkingdom species.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Sirtuínas , Animais , Humanos , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proliferação de Células , Glutamato Desidrogenase/genética , Glutamato Desidrogenase/metabolismo , Histonas , Mamíferos/metabolismo , Sirtuínas/genética , Sirtuínas/química , Sirtuínas/metabolismo
7.
Angew Chem Int Ed Engl ; 61(47): e202204565, 2022 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-36130196

RESUMO

The sirtuin enzymes are a family of lysine deacylases that regulate gene transcription and metabolism. Sirtuin 5 (SIRT5) hydrolyzes malonyl, succinyl, and glutaryl ϵ-N-carboxyacyllysine posttranslational modifications and has recently emerged as a vulnerability in certain cancers. However, chemical probes to illuminate its potential as a pharmacological target have been lacking. Here we report the harnessing of aryl fluorosulfate-based electrophiles as an avenue to furnish covalent inhibitors that target SIRT5. Alkyne-tagged affinity-labeling agents recognize and capture overexpressed SIRT5 in cultured HEK293T cells and can label SIRT5 in the hearts of mice upon intravenous injection of the compound. This work demonstrates the utility of aryl fluorosulfate electrophiles for targeting of SIRT5 and suggests this as a means for the development of potential covalent drug candidates. It is our hope that these results will serve as inspiration for future studies investigating SIRT5 and general sirtuin biology in the mitochondria.


Assuntos
Neoplasias , Sirtuínas , Humanos , Animais , Camundongos , Lisina , Células HEK293 , Sirtuínas/química , Neoplasias/genética
8.
J Biomol Struct Dyn ; 40(20): 10033-10044, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34121619

RESUMO

Sirtuin-6 (SIRT6), class III family of deacetylase regulates several biological functions, including transcriptional repression, telomere maintenance, and DNA repair. It is unique among sirtuin family members with diverse enzymatic functions: mono-ADP-ribosylase, deacetylase and defatty-acylase. The studies so far implicated SIRT6 role in lifespan extension, tumor suppression, and is considered as an attractive drug target for aging-related disease. In this study, we have carried out in silico screening for human SIRT6 modulators using NCI Diversity Set III library, molecular dynamic (MD) simulations to analyze the protein-ligand interaction, and validated their binding-affinity (Kd) using MicroScale Thermophoresis. This study yielded two novel compounds, ((3Z)-3-((4-(dimethylamino)phenyl)methylidene)-5-(5,6,7,8-tetrahydronaphthalen-2-yl)furan-2-one and 5-phenyl-2-(5-phenyl-2,3-dihydro-1,3-benzoxazol-2-yl)-2,3-dihydro-1,3-benzoxazole showing high-affinity interaction for SIRT6. The structural analysis from MD simulation suggests both compounds might act as substrate-analogs or mimic the nicotinamide binding. On considering the uniqueness of SIRT6 substrate binding acyl channel among sirtuin family member, binding of both compounds to the above site suggesting their specificity for SIRT6 isoform. Therefore, it may form the basis for the development of potential modulators for human SIRT6.Communicated by Ramaswamy H. Sarma.


Assuntos
Sirtuínas , Humanos , Sirtuínas/química , Ligantes , Reparo do DNA
9.
Cell Mol Life Sci ; 79(1): 53, 2021 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-34950960

RESUMO

SIRT6 is an NAD+ dependent deacetylase that belongs to the mammalian sirtuin family. SIRT6 is mainly located in the nucleus and regulates chromatin remodeling, genome stability, and gene transcription. SIRT6 extensively participates in various physiological activities such as DNA repair, energy metabolism, oxidative stress, inflammation, and fibrosis. In recent years, the role of epigenetics such as acetylation modification in renal disease has gradually received widespread attention. SIRT6 reduces oxidative stress, inflammation, and renal fibrosis, which is of great importance in maintaining cellular homeostasis and delaying the chronic progression of kidney disease. Here, we review the structure and biological function of SIRT6 and summarize the regulatory mechanisms of SIRT6 in kidney disease. Moreover, the role of SIRT6 as a potential therapeutic target for the progression of kidney disease will be discussed. SIRT6 plays an important role in kidney disease. SIRT6 regulates mitochondrial dynamics and mitochondrial biogenesis, induces G2/M cycle arrest, and plays an antioxidant role in nephrotoxicity, IR, obstructive nephropathy, and sepsis-induced AKI. SIRT6 prevents and delays progressive CKD induced by hyperglycemia, kidney senescence, hypertension, and lipid accumulation by regulating mitochondrial biogenesis, and has antioxidant, anti-inflammatory, and antifibrosis effects. Additionally, hypoxia, inflammation, and fibrosis are the main mechanisms of the AKI-to-CKD transition. SIRT6 plays a critical role in the AKI-to-CKD transition and kidney repair through anti-inflammatory, antifibrotic, and mitochondrial quality control mechanisms. AKI Acute kidney injury, CKD Chronic kidney disease.


Assuntos
Nefropatias/metabolismo , Rim/metabolismo , Sirtuínas , Animais , Epigênese Genética , Humanos , Rim/citologia , Rim/patologia , Camundongos , Mitocôndrias/metabolismo , Sirtuínas/química , Sirtuínas/fisiologia
10.
Molecules ; 26(19)2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34641501

RESUMO

Diabetes mellitus is a global threat affecting millions of people of different age groups. In recent years, the development of naturally derived anti-diabetic agents has gained popularity. Okra is a common vegetable containing important bioactive components such as abscisic acid (ABA). ABA, a phytohormone, has been shown to elicit potent anti-diabetic effects in mouse models. Keeping its anti-diabetic potential in mind, in silico study was performed to explore its role in inhibiting proteins relevant to diabetes mellitus- 11ß-hydroxysteroid dehydrogenase (11ß-HSD1), aldose reductase, glucokinase, glutamine-fructose-6-phosphate amidotransferase (GFAT), peroxisome proliferator-activated receptor-gamma (PPAR-gamma), and Sirtuin family of NAD(+)-dependent protein deacetylases 6 (SIRT6). A comparative study of the ABA-protein docked complex with already known inhibitors of these proteins relevant to diabetes was compared to explore the inhibitory potential. Calculation of molecular binding energy (ΔG), inhibition constant (pKi), and prediction of pharmacokinetics and pharmacodynamics properties were performed. The molecular docking investigation of ABA with 11-HSD1, GFAT, PPAR-gamma, and SIRT6 revealed considerably low binding energy (ΔG from -8.1 to -7.3 Kcal/mol) and predicted inhibition constant (pKi from 6.01 to 5.21 µM). The ADMET study revealed that ABA is a promising drug candidate without any hazardous effect following all current drug-likeness guidelines such as Lipinski, Ghose, Veber, Egan, and Muegge.


Assuntos
Abelmoschus/química , Ácido Abscísico/farmacologia , Diabetes Mellitus/metabolismo , Hipoglicemiantes/farmacologia , Proteínas/metabolismo , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/antagonistas & inibidores , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/química , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/metabolismo , Ácido Abscísico/química , Ácido Abscísico/metabolismo , Ácido Abscísico/farmacocinética , Aldeído Redutase/química , Aldeído Redutase/metabolismo , Simulação por Computador , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Glucoquinase/química , Glucoquinase/metabolismo , Glutamina/metabolismo , Glutamina-Frutose-6-Fosfato Transaminase (Isomerizante)/metabolismo , Quinase 3 da Glicogênio Sintase/química , Quinase 3 da Glicogênio Sintase/metabolismo , Humanos , Hipoglicemiantes/química , Simulação de Acoplamento Molecular , PPAR gama/química , PPAR gama/metabolismo , Proteínas/química , Sirtuínas/química , Sirtuínas/metabolismo
11.
Bioorg Chem ; 117: 105425, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34695733

RESUMO

Histone deacylase 11 and human sirtuins are able to remove fatty acid-derived acyl moieties from the ε-amino group of lysine residues. Specific substrates are needed for investigating the biological functions of these enzymes. Additionally, appropriate screening systems are required for identification of modulators of enzymatic activities of HDAC11 and sirtuins. We designed and synthesized a set of activity probes by incorporation of a thioamide quencher unit into the fatty acid-derived acyl chain and a fluorophore in the peptide sequence. Systematic variation of both fluorophore and quencher position resulted "super-substrates" with catalytic constants of up to 15,000,000 M-1s-1 for human sirtuin 2 (Sirt2) enabling measurements using enzyme concentrations down to 100 pM in microtiter plate-based screening formats. It could be demonstrated that the stalled intermediate formed by the reaction of Sirt2-bound thiomyristoylated peptide and NAD+ has IC50 values below 200 pM.


Assuntos
Corantes Fluorescentes/química , Histona Desacetilases/metabolismo , Tomografia por Emissão de Pósitrons , Sirtuínas/metabolismo , Tioamidas/química , Transporte de Elétrons , Corantes Fluorescentes/farmacologia , Histona Desacetilases/química , Histona Desacetilases/genética , Humanos , Estrutura Molecular , Processos Fotoquímicos , Sirtuínas/antagonistas & inibidores , Sirtuínas/química , Tioamidas/farmacologia
12.
Open Biol ; 11(6): 210047, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34129782

RESUMO

SIRT7 is a class III histone deacetylase that belongs to the sirtuin family. The past two decades have seen numerous breakthroughs in terms of understanding SIRT7 biological function. We now know that this enzyme is involved in diverse cellular processes, ranging from gene regulation to genome stability, ageing and tumorigenesis. Genomic instability is one hallmark of cancer and ageing; it occurs as a result of excessive DNA damage. To counteract such instability, cells have evolved a sophisticated regulated DNA damage response mechanism that restores normal gene function. SIRT7 seems to have a critical role in this response, and it is recruited to sites of DNA damage where it recruits downstream repair factors and directs chromatin regulation. In this review, we provide an overview of the role of SIRT7 in DNA repair and maintaining genome stability. We pay particular attention to the implications of SIRT7 function in cancer and ageing.


Assuntos
Regulação da Expressão Gênica , Instabilidade Genômica , Sirtuínas/metabolismo , Envelhecimento/genética , Envelhecimento/metabolismo , Animais , Dano ao DNA , Reparo do DNA , Suscetibilidade a Doenças , Histonas/metabolismo , Humanos , Isoenzimas/genética , Isoenzimas/metabolismo , Família Multigênica , Neoplasias/etiologia , Neoplasias/metabolismo , Neoplasias/patologia , Transporte Proteico , Sirtuínas/química , Sirtuínas/genética , Relação Estrutura-Atividade
13.
Annu Rev Biochem ; 90: 245-285, 2021 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-33848425

RESUMO

Protein lysine acetylation is an important posttranslational modification that regulates numerous biological processes. Targeting lysine acetylation regulatory factors, such as acetyltransferases, deacetylases, and acetyl-lysine recognition domains, has been shown to have potential for treating human diseases, including cancer and neurological diseases. Over the past decade, many other acyl-lysine modifications, such as succinylation, crotonylation, and long-chain fatty acylation, have also been investigated and shown to have interesting biological functions. Here, we provide an overview of the functions of different acyl-lysine modifications in mammals. We focus on lysine acetylation as it is well characterized, and principles learned from acetylation are useful for understanding the functions of other lysine acylations. We pay special attention to the sirtuins, given that the study of sirtuins has provided a great deal of information about the functions of lysine acylation. We emphasize the regulation of sirtuins to illustrate that their regulation enables cells to respond to various signals and stresses.


Assuntos
Lisina/metabolismo , Mamíferos/metabolismo , Sirtuínas/química , Sirtuínas/metabolismo , Acetilação , Acilação , Animais , Cromatina/genética , Cromatina/metabolismo , Histona Acetiltransferases/metabolismo , Humanos , Processamento de Proteína Pós-Traducional
14.
Biomed Pharmacother ; 138: 111452, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33684691

RESUMO

Sirtuin 6 (SIRT6), a member of sirtuin family (SIRT1-7), regulates a variety of cellular processes involved in aging, metabolism, and cancer. Dysregulation of SIRT6 is widely observed in different breast cancer subtypes; however, the role and function of SIRT6 in cancer development remain largely unexplored. The aim of this study was to identify novel compounds targeting SIRT6 which may provide a new approach in development of anti-cancer therapy for breast cancer. Virtual screening was utilized to discover potential compounds targeting SIRT6 for in vitro screening. In addition, novel 1,4-dihydropyridine derivatives were synthetized and further subjected for the screening. The impact of the compounds on the deacetylation activity of SIRT6 was determined with HPLC method. The anti-cancer activities were screened for a panel of breast cancer cells. A set of 1,4-dihydropyridine derivatives was identified as SIRT6 inhibitors. A SIRT6 activating compound, (2,4-dihydroxy-phenyl)-2-oxoethyl 2-(3-methyl-4-oxo-2-phenyl-4H-chromen-8-yl)acetate (later called as 4H-chromen), was discovered and it provided 30-40-fold maximal activation. 4H-chromen was proposed to bind similarly to quercetin and place to previously reported SIRT6 activator sites. 4H-chromen was investigated in various breast cancer cells, and it decreased cell proliferation in all cells as well as arrested cell cycle in triple negative cells. Overall, this study describes a highly potent SIRT6 activator and new inhibitors that represent a novel tool to study the mechanism of SIRT6 function.


Assuntos
Antineoplásicos/uso terapêutico , Neoplasias da Mama/metabolismo , Sirtuínas/antagonistas & inibidores , Sirtuínas/metabolismo , Antineoplásicos/química , Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Detecção Precoce de Câncer/métodos , Feminino , Humanos , Simulação de Acoplamento Molecular/métodos , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Sirtuínas/química
15.
Int J Mol Sci ; 22(2)2021 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-33418837

RESUMO

Alternative splicing generates multiple distinct isoforms that increase transcriptome and proteome diversity. There are seven sirtuin genes in humans, each consists of multiple exons that are likely to undergo alternative splicing. Our aim was to characterize the effect of alternative splicing on the sirtuin genes. Here, we report the identification of 23 human sirtuin isoforms, most of which were not previously reported. Five of the sirtuin genes had more than one isoform, whereas sirtuin-6 had nine isoforms. Exon skipping was the main event. Most of the sirtuin isoforms were deficient in parts of the protein domains, including the catalytic domain, the N- or C-terminus, nuclear localization signal or mitochondrial targeting signal. The domain loss caused potential structural changes. Three SIRT1 isoforms had a differential effect on the mitochondrial oxygen consumption rate. Age-related changes in the expression of SIRT1 isoforms were observed in the human heart in fetus, adults, and very old individuals. We also identified 15 sirtuin isoforms in mice. Our data indicate that alternative splicing increases sirtuin gene diversity and may modulate subcellular localization and function, thereby adding complexity to the gene regulation of mitochondrial respiration, metabolism, and cardiac function during maturation and aging.


Assuntos
Variação Genética , Sirtuínas/genética , Processamento Alternativo , Animais , Éxons , Loci Gênicos , Genoma , Humanos , Camundongos , Mitocôndrias/metabolismo , Miocárdio/metabolismo , Domínios Proteicos , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Estrutura Terciária de Proteína , RNA Mensageiro/metabolismo , Sirtuínas/química , Sirtuínas/metabolismo , Zinco/química , Zinco/metabolismo
16.
Molecules ; 26(1)2020 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-33375102

RESUMO

NAD+ (nicotinamide adenine dinucleotide)-dependent protein deacylases, namely, the sirtuins, are important cell adaptor proteins that alter cell physiology in response to low calorie conditions. They are thought to mediate the beneficial effects of calorie restriction to extend longevity and improve health profiles. Novel chemical probes are highly desired for a better understanding of sirtuin's roles in various biological processes. We developed a group of remarkably simple activity-based chemical probes for the investigation of active sirtuin content in complex native proteomes. These probes harbor a thioacyllysine warhead, a diazirine photoaffinity tag, as well as a terminal alkyne bioorthogonal functional group. Compared to their benzophenone-containing counterparts, these new probes demonstrated improved labeling efficiency and sensitivity, shortened irradiation time, and reduced background signal. They were applied to the labeling of individual recombinant proteins, protein mixtures, and whole cell lysate. These cell permeable small molecule probes also enabled the cellular imaging of sirtuin activity change. Taken together, our study provides new chemical biology tools and future drug discovery strategies for perturbing the activity of different sirtuin isoforms.


Assuntos
Descoberta de Drogas/métodos , Sondas Moleculares/química , Sirtuínas/química , Técnicas de Química Sintética , Diazometano/química , Desenho de Fármacos , Inibidores de Histona Desacetilases/química , Inibidores de Histona Desacetilases/farmacologia , Humanos , Isoenzimas , Ligantes , Estrutura Molecular , NAD/metabolismo , Sirtuínas/antagonistas & inibidores , Sirtuínas/metabolismo , Coloração e Rotulagem , Relação Estrutura-Atividade
17.
Nat Commun ; 11(1): 5244, 2020 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-33067423

RESUMO

The protein deacetylase SIRT6 maintains cellular homeostasis through multiple pathways that include the deacetylation of histone H3 and repression of transcription. Prior work suggests that SIRT6 is associated with chromatin and can substantially reduce global levels of H3 acetylation, but how SIRT6 is able to accomplish this feat is unknown. Here, we describe an exquisitely tight interaction between SIRT6 and nucleosome core particles, in which a 2:1 enzyme:nucleosome complex assembles via asymmetric binding with distinct affinities. While both SIRT6 molecules associate with the acidic patch on the nucleosome, we find that the intrinsically disordered SIRT6 C-terminus promotes binding at the higher affinity site through recognition of nucleosomal DNA. Together, multivalent interactions couple productive binding to efficient deacetylation of histones on endogenous chromatin. Unique among histone deacetylases, SIRT6 possesses the intrinsic capacity to tightly interact with nucleosomes for efficient activity.


Assuntos
Cromatina/metabolismo , Nucleossomos/metabolismo , Sirtuínas/metabolismo , Acetilação , Cromatina/genética , Histonas/genética , Histonas/metabolismo , Humanos , Nucleossomos/genética , Ligação Proteica , Domínios Proteicos , Sirtuínas/química , Sirtuínas/genética
18.
J Biol Chem ; 295(52): 18355-18366, 2020 12 25.
Artigo em Inglês | MEDLINE | ID: mdl-33122195

RESUMO

Sirtuin 6, SIRT6, is critical for both glucose and lipid homeostasis and is involved in maintaining genomic stability under conditions of oxidative DNA damage such as those observed in age-related diseases. There is an intense search for modulators of SIRT6 activity, however, not many specific activators have been reported. Long acyl-chain fatty acids have been shown to increase the weak in vitro deacetylase activity of SIRT6 but this effect is modest at best. Herein we report that electrophilic nitro-fatty acids (nitro-oleic acid and nitro-conjugated linoleic acid) potently activate SIRT6. Binding of the nitro-fatty acid to the hydrophobic crevice of the SIRT6 active site exerted a moderate activation (2-fold at 20 µm), similar to that previously reported for non-nitrated fatty acids. However, covalent Michael adduct formation with Cys-18, a residue present at the N terminus of SIRT6 but absent from other isoforms, induced a conformational change that resulted in a much stronger activation (40-fold at 20 µm). Molecular modeling of the resulting Michael adduct suggested stabilization of the co-substrate and acyl-binding loops as a possible additional mechanism of SIRT6 activation by the nitro-fatty acid. Importantly, treatment of cells with nitro-oleic acid promoted H3K9 deacetylation, whereas oleic acid had no effect. Altogether, our results show that nitrated fatty acids can be considered a valuable tool for specific SIRT6 activation, and that SIRT6 should be considered as a molecular target for in vivo actions of these anti-inflammatory nitro-lipids.


Assuntos
Ácidos Graxos/farmacologia , Nitrocompostos/farmacologia , Sirtuínas/metabolismo , Acetilação , Humanos , Estresse Oxidativo , Conformação Proteica , Sirtuínas/química , Sirtuínas/genética
19.
Adv Protein Chem Struct Biol ; 122: 203-229, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32951812

RESUMO

There is a growing interest to study and address neglected tropical diseases (NTD). To this end, in silico methods can serve as the bridge that connects academy and industry, encouraging the development of future treatments against these diseases. This chapter discusses current challenges in the development of new therapies, available computational methods and successful cases in computer-aided design with particular focus on human trypanosomiasis. Novel targets are also discussed. As a case study, we identify amentoflavone as a potential inhibitor of TcSir2rp3 (sirtuine) from Trypanosoma cruzi (20.03 µM) with a workflow that integrates chemoinformatic approaches, molecular modeling, and theoretical affinity calculations, as well as in vitro assays.


Assuntos
Biflavonoides/química , Doença de Chagas , Simulação por Computador , Inibidores Enzimáticos/química , Proteínas de Protozoários , Sirtuínas , Tripanossomicidas/química , Trypanosoma cruzi/enzimologia , Biflavonoides/uso terapêutico , Doença de Chagas/tratamento farmacológico , Doença de Chagas/enzimologia , Inibidores Enzimáticos/uso terapêutico , Humanos , Proteínas de Protozoários/antagonistas & inibidores , Proteínas de Protozoários/química , Sirtuínas/antagonistas & inibidores , Sirtuínas/química , Tripanossomicidas/uso terapêutico
20.
Biomed Pharmacother ; 131: 110701, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32905943

RESUMO

Sirtuin 6 (SIRT6), a member of sirtuin family (SIRT1-7), regulates distinct cellular functions; genome stability, DNA repair, and inflammation related diseases. Recently, we demonstrated that anthocyanidins in berries induce the catalytic activity of SIRT6. In this study, we explored the effects of Galloflavin and Ellagic acid, the most common polyphenols in berries, on SIRT6. SIRT6 deacetylation was investigated using HPLC and immunoblotting assays. The expression levels of SIRT6, glycolytic proteins and cellular metabolism were studied on human colon adenocarcinoma cells (Caco2). Molecular docking studies were carried out to study possible interactions of the compounds with sirtuins. Ellagic acid increased the deacetylase activity of SIRT6 by up to 50-fold; it showed moderate inhibition of SIRT1-3. Galloflavin and Ellagic acid showed anti-proliferative effects on Caco2. The compounds also upregulated SIRT6 expression whereas key proteins in glycolysis were downregulated. Galloflavin decreased glucose transporter 1 (GLUT1) expression, and Ellagic acid affected the expression of protein dehydrogenase kinase 1 (PDK1). Interestingly, both compounds caused reduction in glucose uptake and lactate production. Both Galloflavin and Ellagic acid were able to form hydrogen bonds with Asp188 and Gly6 in SIRT6. In this study, we showed that Galloflavin and Ellagic acid increased SIRT6 activity and decreased the expression of SIRT6 associated proteins involved in cancer development. Taken together, Galloflavin and Ellagic acid targeting SIRT6 activity may provide a new insight in the development of anti-cancer therapy.


Assuntos
Antineoplásicos/farmacologia , Ácido Elágico/farmacologia , Isocumarinas/farmacologia , Sirtuínas/metabolismo , Acetilação , Células CACO-2 , Glucose/metabolismo , Transportador de Glucose Tipo 1/genética , Humanos , Simulação de Acoplamento Molecular , Piruvato Desidrogenase Quinase de Transferência de Acetil/genética , Sirtuínas/química
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