sirtuin
Dotaz
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Sirtuiny, pojmenované podle jejich homologního proteinu „Silent Information Regulator Two“ pocházejícího z kvasinky Saccharomyces cerevisiae, představují skupinu vysoce mezidruhově konzervovaných nikotinamidadenindinukleotid dependentních enzymů, které deacetylují histony a odštěpují acetyl z lysinových reziduí proteinů. Hlavním cílem tohoto článku je stručně přiblížit farmakologický význam hlavních aktivátorů sirtuinu 1 přírodního nebo syntetického původu, které byly v průběhu posledních několika let testovány zejména při oxidativním poškození. V článku je především popsána související biologická aktivita těchto látek vzhledem k tomu, že jsou považovány za „favority“ při hledání nových farmakologicky aktivních látek a potenciálních léčiv. Díky nedávnému vývoji znalostí o vzájemné komunikaci mezi sirtuinem 1 a jeho modulátory (např. resveratrolem) získává farmakologický a klinický výzkum v této oblasti novou perspektivu.
Sirtuins, named after their homology to the Saccharomyces cerevisiae Silent Information Regulator Two, constitute a family of highly conserved nicotinamide adenine dinucleotide-dependent enzymes that deacetylate histones and residues of acetylated lysine. The main aim of this article is to put forward the pharmacological importance of major sirtuin 1 activators of natural or synthetic origin tested in last years in cases of oxidative tissue damage. The related bioactivity of these activators as “leading” compounds in the search for new drugs and remedies is also described. With the recent development of our knowledge on the cross talks between sirtuin 1 and its modulators (e.g. resveratrol), pharmacological and clinical research on this topic is getting a new horizon.
- Klíčová slova
- antioxidanty, metabolická onemocnění, nutraceutika, oxidativní stres, SIRT1 aktivátory,
- MeSH
- antioxidancia farmakologie fyziologie MeSH
- dlouhověkost MeSH
- kalorická restrikce MeSH
- lidé MeSH
- oxidační stres fyziologie MeSH
- polyfenoly MeSH
- resveratrol MeSH
- sirtuin 1 fyziologie MeSH
- sirtuiny MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
Lysine deacetylases, like histone deacetylases (HDACs) and sirtuins (SIRTs), are involved in many regulatory processes such as control of metabolic pathways, DNA repair, and stress responses. Besides robust deacetylase activity, sirtuin isoforms SIRT2 and SIRT3 also show demyristoylase activity. Interestingly, most of the inhibitors described so far for SIRT2 are not active if myristoylated substrates are used. Activity assays with myristoylated substrates are either complex because of coupling to enzymatic reactions or time-consuming because of discontinuous assay formats. Here we describe sirtuin substrates enabling direct recording of fluorescence changes in a continuous format. Fluorescence of the fatty acylated substrate is different when compared to the deacylated peptide product. Additionally, the dynamic range of the assay could be improved by the addition of bovine serum albumin, which binds the fatty acylated substrate and quenches its fluorescence. The main advantage of the developed activity assay is the native myristoyl residue at the lysine side chain avoiding artifacts resulting from the modified fatty acyl residues used so far for direct fluorescence-based assays. Due to the extraordinary kinetic constants of the new substrates (KM values in the low nM range, specificity constants between 175,000 and 697,000 M-1s-1) it was possible to reliably determine the IC50 and Ki values for different inhibitors in the presence of only 50 pM of SIRT2 using different microtiter plate formats.
D-Galactosamine/Lipopolysaccharide (D-GalN/LPS) is a well known model of hepatotoxicity that closely resembles acute liver failure (ALF) seen clinically. The role of sirtuin 1 in this model has not yet been documented. However, there have been a number of studies about the cytoprotective effects of resveratrol, a SIRT1 activator, in the liver. This study was aimed at elucidating the roles of SIRT1 protein expression or catalytic activity in D-GalN/LPS model of hepatotoxicity. ALF was induced in male Wistar rats by intraperitoneal injection of D-GalN and LPS. Some groups of animals were pretreated with resveratrol and/or EX-527 (SIRT1 inhibitor). The effects of these treatments were evaluated by biochemical and Western blot studies. D-GalN/LPS treatment was able to induce hepatotoxicity and significantly increase all markers of liver damage and lipid peroxidation. A dramatic decrease of SIRT1 levels in response to D-GalN/LPS treatment was also documented. Resveratrol pretreatment attenuated D-GalN/LPS-induced hepatotoxicity. EX-527 blocked the cytoprotective effects of resveratrol. However, both resveratrol and EX-527 pretreatments did not exhibit any significant effect on SIRT1 protein expression. Collectively, these results suggest that downregulation of SIRT1 expression is involved in the cytotoxic effects of D-GalN/LPS model and SIRT1 activity contributes to the cytoprotective effects of resveratrol in the liver.
- MeSH
- antioxidancia farmakologie MeSH
- cytoprotekce MeSH
- down regulace MeSH
- galaktosamin * MeSH
- inhibitory enzymů farmakologie MeSH
- játra účinky léků enzymologie patologie MeSH
- karbazoly farmakologie MeSH
- lékové postižení jater enzymologie etiologie patologie prevence a kontrola MeSH
- lipopolysacharidy * MeSH
- modely nemocí na zvířatech MeSH
- peroxidace lipidů účinky léků MeSH
- potkani Wistar MeSH
- sirtuin 1 antagonisté a inhibitory metabolismus MeSH
- stilbeny farmakologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Sirtuin activating compounds (STACs) attenuate various type of liver insults through mechanisms which are not fully understood. In the present study, we investigated the ameliorative potential of quercetin (natural polyphenol) and SRT1720 (synthetic SIRT1 activator) against D-galactosamine/lipopolysaccharide-induced hepatotoxicity (an experimental model of acute liver failure). Moreover, we compared and contrasted the roles of stress responsive enzymes, sirtuin 1 (SIRT1) and heme oxygenase 1 (HO-1) in hepatoprotection/ hepatotoxicity. Liver injury was induced in male Wistar rats by intraperitoneal injection of D-galactosamine (400 mg/kg) and lipopolysaccharide (10 microg/kg). Some animals were pretreated with quercetin (50 mg/kg i.p.) or SRT1720 (5 mg/kg i.p.). Twenty-four hours later, the effects of these treatments were evaluated by biochemical studies and Western blot. D-GalN/LPS treatment upregulated HO-1 expression, downregulated SIRT1 expression, decreased AST: ALT ratio and markedly increased bilirubin, catalase and conjugated diene levels. Pretreatment of D-GalN/LPS rats with either quercetin or SRT1720 returned SIRT1 expression, HO-1 expression and all the aforementioned markers towards normal. Collectively, these findings suggest that elevated HO-1 and low SIRT1 expressions are involved in the pathogenesis of D-GalN/LPS-induced hepatotoxicity. Drugs that downregulate HO-1 and/or upregulate SIRT1 seem to have antihepatotoxic effects and need further exploration.
- MeSH
- galaktosamin toxicita MeSH
- hemová oxygenasa (decyklizující) antagonisté a inhibitory metabolismus MeSH
- heterocyklické sloučeniny tetra- a více cyklické farmakologie terapeutické užití MeSH
- krysa rodu rattus MeSH
- lékové postižení jater farmakoterapie metabolismus MeSH
- lipopolysacharidy toxicita MeSH
- náhodné rozdělení MeSH
- potkani Wistar MeSH
- sirtuin 1 metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
A vast collection of data obtained during the last decade supports the view on sirtuins as sensors of actual cellular metabolic state being involved in cell cycle progression, apoptosis/survival decision making, longevity, inflammation etc. Moreover, sirtuins themselves can control metabolism through their ability to consume NAD(+). In turn, cellular NAD parameters may affect the generation of ATP, a main cellular currency of energy. Therefore, sirtuins became recognized as critical affectors of cellular metabolism which participate in fat mobilization, gluconeogenesis, caloric restriction etc. Cellular senescence is viewed as a mechanism to restrict excessive cell growth when it is unnecessary or harmful. It is therefore necessary to understand the mechanism of senescence to design new approaches to combat cancer. Growth in turn depends on metabolism as it requires energy. Therefore, in this review, we address the connection of sirtuins to senescence through their participation in the regulation of metabolic and biochemical parameters and related signaling.
- MeSH
- antiflogistika nesteroidní farmakologie MeSH
- lidé MeSH
- NAD metabolismus MeSH
- signální transdukce MeSH
- sirtuiny účinky léků metabolismus MeSH
- stárnutí účinky léků MeSH
- stilbeny farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
The involvement of the mTOR system/enzyme sirtuin 1 (SIRT1) intracellular signaling system in the control of ovarian functions and its role in mediating hormonal action on the ovary has been proposed, but this hypothesis should be supported by a demonstrated influence of hormones on mTOR/SIRT1. Therefore, the aim of our in vitro experiments was to examine the effect of the known hormonal regulators of ovarian functions, such as follicle-stimulating hormone (FSH), oxytocin (OT) and insulin-like growth factor I (IGF-I), on mTOR/SIRT1. The accumulation of SIRT1 in porcine ovarian granulosa cells cultured with and without these hormones (at doses of 1, 10 or 100 ng.ml-1) was evaluated using immunocytochemistry. It was observed that the addition of FSH (at 10 ng.ml-1 but not at 1 or 100 ng/ml) and OT (at all tested doses) increased the expression of SIRT1 in ovarian cells. In addition, 100 ng.ml-1, but not at 1 or 10 ng.ml-1, of IGF-I decreased SIRT1 accumulation. Our observations are the first demonstration that hormones can directly regulate the ovarian mTOR/SIRT1 system and that this system could mediate the action of hormonal regulators on the ovary.
- MeSH
- apoptóza účinky léků MeSH
- folikulární buňky cytologie účinky léků metabolismus MeSH
- folikuly stimulující hormon farmakologie MeSH
- insulinu podobný růstový faktor I farmakologie MeSH
- kultivované buňky MeSH
- ovarium cytologie účinky léků metabolismus MeSH
- oxytocin farmakologie MeSH
- prasata MeSH
- proliferace buněk účinky léků MeSH
- sirtuin 1 biosyntéza genetika metabolismus MeSH
- uterotonika farmakologie MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: The study was undertaken to evaluate the effect of 6-week supplementation with a daily dose of 2g of curcumin on VO2max and prooxidant/antioxidant homeostasis in middle-aged amateur long-distance runners during the preparatory period of the macrocycle. METHODS: Thirty runners were randomly assigned to a placebo group (PL) and a curcumin-supplemented group (CU). Their VO2max was assessed before supplementation and after 6 weeks of supplementation. Venous blood samples were collected from the participants at rest, immediately after exercise, and after 1h of recovery to evaluate the activity of antioxidant enzymes (SOD, CAT, GPx), non-enzymatic antioxidants (GSH, UA) and sirtuin 3 level (SIRT 3), as well as the levels of oxidative stress markers (TOS/TOC, MDA, and 8-OHdG) and muscle damage markers (CK, LDH, and Mb). RESULTS: VO2max, the activity of enzymatic antioxidants, the concentrations of non-enzymatic antioxidants, the levels of oxidative stress markers, and the levels of muscle damage markers did not change significantly in the CU group over 6 weeks of supplementation with curcumin. However, the resting concentration of SIRT 3 was found to be significantly higher (p ≤ 0.05) compared with pre-supplementation. CONCLUSION: Curcumin supplementation does not have a significant effect on VO2max and prooxidant/antioxidant homeostasis in runners.
- MeSH
- antioxidancia MeSH
- kurkumin * MeSH
- lidé MeSH
- měď MeSH
- potravní doplňky MeSH
- reaktivní formy kyslíku MeSH
- sirtuin 3 * MeSH
- superoxiddismutasa MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- randomizované kontrolované studie MeSH
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.
- MeSH
- fluorescenční barviva chemie farmakologie MeSH
- fotochemické procesy MeSH
- histondeacetylasy chemie genetika metabolismus MeSH
- lidé MeSH
- molekulární struktura MeSH
- pozitronová emisní tomografie * MeSH
- sirtuiny antagonisté a inhibitory chemie metabolismus MeSH
- thioamidy chemie farmakologie MeSH
- transport elektronů MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Aging is a natural process of gradual decrease in physical and mental capacity. Biological age (accumulation of changes and damage) and chronological age (years lived) may differ. Biological age reflects the risk of various types of disease and death from any cause. We selected potential biomarkers of aging - telomerase, AGEs, GDF11 and 15 (growth differentiation factor 11/15), sirtuin 1, NAD+ (nicotinamide adenine dinucleotide), inflammasome NLRP3, DNA/RNA damage, and klotho to investigate changes in their levels depending on age and sex. We included 169 healthy volunteers and divided them into groups according to age (under 35; 35-50; over 50) and sex (male, female; male and female under 35; 35-50, over 50). Markers were analyzed using commercial ELISA kits. We found differences in values depending on age and gender. GDF15 increased with age (under 30 and 35-50 p < 0.002; 35-50 and over 50; p < 0.001; under 35 and over 50; p < 0.001) as well as GDF11 (35-50 and over 50; p < 0.03; under 35 and over 50; p < 0.02), AGEs (under 30 and 35-50; p < 0.005), NLRP3 (under 35 over 50; p < 0.03), sirtuin 1 (35-50 and over 50; p < 0.0001; under 35 and over 50; p < 0.004). AGEs and GDF11 differed between males and females. Correlations were identified between individual markers, markers and age, and markers and sex. Markers that reflect the progression of biological aging vary with age (GDF15, GDF11, AGEs, NLRP3, sirtuin) and sex (AGEs, GDF11). Their levels could be used in clinical practice, determining biological age, risk of age-related diseases and death of all-causes, and initiating or contraindicating a therapy in the elderly based on the patient's health status.
- MeSH
- biologické markery MeSH
- DNA MeSH
- kostní morfogenetické proteiny MeSH
- lidé MeSH
- NAD * MeSH
- produkty pokročilé glykace MeSH
- protein NLRP3 MeSH
- růstové diferenciační faktory metabolismus MeSH
- senioři MeSH
- sirtuin 1 MeSH
- stárnutí genetika MeSH
- telomerasa * MeSH
- zdravotní stav MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The present study was designed to evaluate the therapeutic potential of quercetin in a sub-chronic model of hepatotoxicity. The roles of putative antioxidant enzymes, sirtuin 1 (SIRT1) and heme oxygenase 1 (HO-1), in hepatoprotection were also addressed. Sub-chronic liver injury was induced in rats by intraperitoneal administration of 0.5 ml/kg carbon tetrachloride (CTC), once every 3 days, for 2 weeks. Some CTC rats were concurrently treated with 100 mg/kg quercetin, intragastrically, once every day, for 2 weeks. The effects of these drugs in the liver were evaluated by biochemical, histological, immunohistochemical and molecular biological studies. CTC triggered oxidative damage to the liver as unanimously shown by altered biochemical parameters and liver morphology. Furthermore, CTC highly upregulated HO-1 and SIRT1 expression levels. Concomitant treatment of rats with quercetin downregulated SIRT1 expression and ameliorated the hepatotoxic effects of CTC. However, quercetin did not have any significant effect on HO-1 expression and bilirubin levels. Collectively, these results suggest that the antioxidant and cytoprotective effects of quercetin in CTC treated rats were SIRT1 mediated and less dependent on HO-1. Thus, pharmacologic modulation of SIRT1 could provide a logic therapeutic approach in sub-chronic hepatotoxicity.
- MeSH
- alanintransaminasa krev MeSH
- aspartátaminotransferasy krev MeSH
- bilirubin krev MeSH
- down regulace účinky léků MeSH
- hemoxygenasa-1 metabolismus MeSH
- imunohistochemie MeSH
- játra metabolismus patologie MeSH
- krysa rodu rattus MeSH
- ochranné látky farmakologie MeSH
- otrava chloridem uhličitým metabolismus patologie prevence a kontrola MeSH
- potkani Wistar MeSH
- quercetin farmakologie MeSH
- sirtuin 1 metabolismus MeSH
- upregulace účinky léků MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
