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Xiangying Guan, Alok Upadhyay, Sudipto Munshi, Raj Chakrabarti
Across all families of enzymes, only a dozen or so distinct classes of non-natural small molecule activators have been characterized, with only four known modes of activation among them. All of these modes of activation rely on naturally evolved binding sites that trigger global conformational changes. Among the enzymes that are of greatest interest for small molecule activation are the seven sirtuin enzymes, nicotinamide adenine dinucleotide (NAD+)-dependent protein deacylases that play a central role in the regulation of healthspan and lifespan in organisms ranging from yeast to mammals...
2018: PloS One
María Paula Ceballos, Giulia Decándido, Ariel Darío Quiroga, Carla Gabriela Comanzo, Verónica Inés Livore, Florencia Lorenzetti, Flavia Lambertucci, Lorena Chazarreta-Cifre, Claudia Banchio, María de Luján Alvarez, Aldo Domingo Mottino, María Cristina Carrillo
Sirtuins (SIRTs) 1 and 2 deacetylases are overexpressed in hepatocellular carcinoma (HCC) and are associated with tumoral progression and multidrug resistance (MDR). In this study we analyzed whether SIRTs 1 and 2 activities blockage was able to affect cellular survival and migration and to modulate p53 and FoxO1 acetylation in HepG2 and Huh7 cells. Moreover, we analyzed ABC transporters P-glycoprotein (P-gp) and multidrug resistance-associated protein 3 (MRP3) expression. We used cambinol and EX-527 as SIRTs inhibitors...
March 12, 2018: Toxicology Letters
Céline Ronin, David Mendes Costa, Joana Tavares, Joana Faria, Fabrice Ciesielski, Paola Ciapetti, Terry K Smith, Jane MacDougall, Anabela Cordeiro-da-Silva, Iain K Pemberton
The de novo crystal structure of the Leishmania infantum Silent Information Regulator 2 related protein 1 (LiSir2rp1) has been solved at 1.99Å in complex with an acetyl-lysine peptide substrate. The structure is broadly commensurate with Hst2/SIRT2 proteins of yeast and human origin, reproducing many of the structural features common to these sirtuin deacetylases, including the characteristic small zinc-binding domain, and the larger Rossmann-fold domain involved in NAD+-binding interactions. The two domains are linked via a cofactor binding loop ordered in open conformation...
2018: PloS One
Lucyna Kaszubowska, Jerzy Foerster, Jan Jacek Kaczor, Daria Schetz, Tomasz Jerzy Ślebioda, Zbigniew Kmieć
Background: Natural killer cells (NK cells) are cytotoxic lymphocytes of innate immunity that reveal some immunoregulatory properties, however, their role in the process of ageing is not completely understood. The study aimed to analyze the expression of proteins involved in cellular stress response: sirtuin 1 (SIRT1), heat shock protein 70 (HSP70) and manganese superoxide dismutase (SOD2) in human NK cells with reference to the process of ageing. Non-stimulated and stimulated with IL-2, LPS or PMA with ionomycin cells originated from peripheral blood samples of: seniors aged over 85 ('the oldest'; n  = 25; 88...
2018: Immunity & Ageing: I & A
Cristina Fernández-García, Lisa Rancan, Sergio D Paredes, César Montero, Mónica de la Fuente, Elena Vara, Jesús A F Tresguerres
BACKGROUND AND AIMS: Aging is associated with a deregulation of biological systems that lead to an increase in oxidative stress, inflammation, and apoptosis, among other effects. Xanthohumol is the main preylated chalcone present in hops (Humulus lupulus L.) whose antioxidant, anti-inflammatory and chemopreventive properties have been shown in recent years. In the present study, the possible protective effects of xanthohumol on liver alterations associated with aging were evaluated. METHODS: Male young and old senescence-accelerated prone mice (SAMP8), aged 2 and 10 months, respectively, were divided into four groups: non-treated young, non-treated old, old treated with 1 mg/kg/day xanthohumol, and old treated with 5 mg/kg/day xanthohumol...
March 13, 2018: European Journal of Nutrition
Jiangying Kuang, Lei Chen, Qin Tang, Jinhang Zhang, Yanping Li, Jinhan He
Sirt6 is one of the sirtuin family members, a kind of NAD+-dependent histone deacetylase and ADP-ribose transferase enzyme. It has an important role in physiological and pathological processes, regulating aging, cancer, obesity, insulin resistance, inflammation, and energy metabolism. Recent studies have suggested that reduced Sirt6 action is related to obesity and diabetes. Aging and overnutrition, two major risk factors for obesity and diabetes, lead to decreased Sirt6 level and function, which results in abnormal glucose and lipid metabolism...
2018: Frontiers in Physiology
Jinghua Liu, Zhen Yu, Yuanyuan Xiao, Qiong Meng, Yeying Wang, Wei Chang
Background: The Forkhead transcription family member FOXA2 plays a fundamental role in hepatocellular carcinoma (HCC) progression, but the precise interaction factor and molecular regulation of FOXA2 are not fully understood. Objective: In this study, we found that FOXA2 could interact with sirtuin 6 (SIRT6) directly in vivo and in vitro. We explored that the expressions of FOXA2 and SIRT6 were significantly downregulated in human HCC and HCC cell lines. Methods: Functionally, cell counting kit-8 assay and Transwell® assay were performed; we demonstrated that the knockdown of FOXA2 and SIRT6 promoted HepG2 cells and Huh7 cells proliferation and invasion in vitro...
2018: Cancer Management and Research
Xuejiao Li, Zhongxiu Jiang, Xiangmin Li, Xiaoye Zhang
Osteopontin (OPN) is a promoter for tumor progression. It has been reported to promote non-small cell lung cancer (NSCLC) progression via the activation of nuclear factor-κB (NF-κB) signaling. As the increased acetylation of NF-κB p65 is linked to NF-κB activation, the regulation of NF-κB p65 acetylation could be a potential treatment target for OPN-induced NSCLC progression. Sirtuin 1 (SIRT1) is a deacetylase, and the role of SIRT1 in tumor progression is still controversial. The effect and mechanism of SIRT1 on OPN-induced tumor progression remains unknown...
2018: OncoTargets and Therapy
Ling Ma, Qiao Cheng
Anaplastic thyroid carcinoma (ATC) is the most aggressive type of thyroid malignancies and resistant to chemotherapy. Little is known on the underlying mechanisms of ATC resistance to chemotherapy. In our work, we identified that 6-phosphogluconate dehydrogenase (6PGD) is critically involved in the development of ATC resistance to doxorubicin. We found that 6PGD mRNA, protein and enzyme activity levels are significantly upregulated in ATC cells during the prolonged exposure to doxorubicin in a time-dependent manner...
March 10, 2018: Biochemical and Biophysical Research Communications
Yan Li, Ying Ma, Liqiang Song, Lu Yu, Le Zhang, Yingmei Zhang, Yuan Xing, Yue Yin, Heng Ma
Mitochondrial dynamics have critical roles in aging, and their impairment represents a prominent risk factor for myocardial dysfunction. Mitochondrial deacetylase sirtuin (SIRT)3 contributes greatly to the prevention of redox stress and cell aging. The present study explored the role of SIRT3 on myocardium aging. Western blot analysis demonstrated that SIRT3 expression levels were significantly lower in the myocardia of aged mice compared with young mice. Immunoprecipitation and western blot assays indicated that the activity of mitochondrial manganese superoxide dismutase (MnSOD) and peroxisome proliferator‑activated receptor γ coactivator (PGC)‑1α was reduced in the aged heart...
March 9, 2018: International Journal of Molecular Medicine
Jonathan Fusi, Sara Bianchi, Simona Daniele, Silvia Pellegrini, Claudia Martini, Fabio Galetta, Luca Giovannini, Ferdinando Franzoni
Oxidative stress arises from an imbalance between the production of free radicals and antioxidant defences. Several studies have suggested that dietary antioxidants (such as polyphenols and berberine) may counteract oxidative stress through the involvement of the Sirtuin 1/Adenosine Monophosphate-Activated Protein Kinase (SIRT1/AMPK) pathway. The aim of this study was to evaluate the direct and specific antioxidant activity of some natural compounds, as well as their ability to modulate the expression of SIRT1 and the activation of AMPK...
March 8, 2018: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
Peng Liu, Tingting Feng, Xuan Zuo, Xiao Wang, Jinque Luo, Ni Li, Xiaowan Han, Ningyu Zhu, Suowen Xu, Yanni Xu, Zheng Gen Jin, Shuyi Si
Sirtuin 1 (SIRT1) is an NAD+ -dependent protein deacetylase that plays a critical role in controlling energy metabolism, stress response and aging. Hence, enhancing SIRT1 activity could be a potential therapeutic strategy to treat metabolic diseases such as diabetes. However, pharmacological activators for SIRT1 are scarce to date. In this study, using the optimized high throughput screening, we identified E6155, a piperazine 1, 4- diamide compound, as a new small molecular activator of SIRT1. We further found that E6155 significantly upregulated glucose uptake in cultured mouse liver cells and skeletal muscle cells through increasing SIRT1 deacetylase activity...
March 7, 2018: Biochemical and Biophysical Research Communications
Ting Hong, Zhijuan Ge, Ran Meng, Hongdong Wang, Pengzi Zhang, Sunyinyan Tang, Jing Lu, Tianwei Gu, Dalong Zhu, Yan Bi
Erythropoietin (EPO), besides its stimulatory effect on erythropoiesis, is beneficial to insulin resistance and obesity. However, its role in hepatic steatosis remains unexplored. Activating autophagy seems a promising mechanism for improving fatty liver disease. The present study investigated the role of EPO in alleviating hepatic steatosis and sought to determine whether its function is mediated by the activation of autophagy. Here, we show that EPO decreased hepatic lipid content significantly in vivo and in vitro...
March 6, 2018: Biochimica et Biophysica Acta
Bong-Geum Jang, Boyoung Choi, Suyeon Kim, Jae-Yong Lee, Min-Ju Kim
Neuroblastoma cell differentiation is a valuable model for studying therapeutic methods in neuroblastoma and the mechanisms of neuronal differentiation. Here, we used trichostatin A (TSA) and sirtinol, which are inhibitors of cHDACs and sirtuins, respectively, to show that classical histone deacetylases (cHDACs) and sirtuins (silent mating type information regulation 2 homolog; SIRTs) affect all-trans retinoic acid (ATRA)-induced differentiation of neuroblastoma cells. After first determining neurite elongation and expression levels of tyrosine hydroxylase and high size neurofilament as useful differentiation markers, we observed that TSA increased neuroblastoma cell differentiation, while sirtinol had the antagonistic effect of decreasing it...
March 7, 2018: Journal of Molecular Neuroscience: MN
Francesca Bonomini, Gaia Favero, Luigi Fabrizio Rodella, Mohammed H Moghadasian, Rita Rezzani
Hypercholesterolemia increases and exacerbates stress signals leading also to liver damage (LD) and failure. Sirtuin1 (SIRT1) is involved in lifespan extension and it plays an essential role in hepatic lipid metabolism. However, its involvement in liver hypercholesterolemic damage is not yet completely defined. This in vivo study evaluated the role of SIRT1 in the hypercholesterolemic-related LD and, then, investigated how oral supplementation of melatonin, pleiotropic indoleamine, may be protective. Control mice and apolipoprotein E-deficient mice (ApoE-/- ) of 6 and 15 weeks of age were treated or not treated with melatonin at the dose of 10 mg/kg/day for 9 weeks...
2018: BioMed Research International
Minna Rahnasto-Rilla, Jonna Tyni, Marjo Huovinen, Elina Jarho, Tomasz Kulikowicz, Sarangan Ravichandran, Vilhelm A Bohr, Luigi Ferrucci, Maija Lahtela-Kakkonen, Ruin Moaddel
Flavonoids are polyphenolic secondary metabolites synthesized by plants and fungus with various pharmacological effects. Due to their plethora of biological activities, they have been studied extensively in drug development. They have been shown to modulate the activity of a NAD+ -dependent histone deacetylase, SIRT6. Because SIRT6 has been implicated in longevity, metabolism, DNA-repair, and inflammatory response reduction, it is an interesting target in inflammatory and metabolic diseases as well as in cancer...
March 7, 2018: Scientific Reports
Edward T Morgan, Joseph L Dempsey, Sylvie M Mimche, Tracey J Lamb, Supriya Kulkarni, Julia Yue Cui, Hyunyoung Jeong, Angela L Slitt
This article is a report on a symposium entitled "Physiological Regulation of Drug Metabolism and Transport" sponsored by the American Society for Pharmacology and Experimental Therapeutics and held at the Experimental Biology 2017 meeting in Chicago, IL. The contributions of physiological and pathophysiological regulation of drug metabolizing enzymes and transporters to interindividual variability in drug metabolism are increasingly recognized, but are in many cases not well understood. The presentations herein discuss the phenomenology, consequences and mechanism of such regulation...
March 7, 2018: Drug Metabolism and Disposition: the Biological Fate of Chemicals
Chris Carrico, Jesse G Meyer, Wenjuan He, Brad W Gibson, Eric Verdin
Post-translational modification of lysine residues via reversible acylation occurs on proteins from diverse pathways, functions, and organisms. While nuclear protein acylation reflects the competing activities of enzymatic acyltransferases and deacylases, mitochondrial acylation appears to be driven mostly via a non-enzymatic mechanism. Three protein deacylases, SIRT3, SIRT4, and SIRT5, reside in the mitochondria and remove these modifications from targeted proteins in an NAD+ -dependent manner. Recent proteomic surveys of mitochondrial protein acylation have identified the sites of protein acetylation, succinylation, glutarylation, and malonylation and their regulation by SIRT3 and SIRT5...
March 6, 2018: Cell Metabolism
Xing-Xing He, Chen-Kai Huang, Bu-Shan Xie
The exact molecular mechanism of 5-fluorouracil (5-FU) in human gastric cancer cells remains to be elucidated. Cultured BGC‑823 human gastric carcinoma and AGS cell lines were treated with 5‑FU. Autophagosome formation was investigated through multiple approaches, including the quantification of green fluorescent protein‑microtubule‑associated protein 1A/1B‑light chain 3 (LC3) puncta, LC3 conversion and electron microscopy observations. Additionally, autophagy was inhibited using 3‑methyladenine (3‑MA) and beclin‑1 ablation, to determine its role in 5‑FU‑mediated cell death...
March 1, 2018: Molecular Medicine Reports
Hanlin Yao, Zhen Yao, Shaocheng Zhang, Wenjun Zhang, Wen Zhou
Osteoporosis is a disease that significantly influences life expectancy and quality in humans. Oxidative stress may stimulate bone marrow osteoclast differentiation and inhibit osteoblast (OB) differentiation. OB proliferation and differentiation are affected by the forkhead box O (FoxO)1/β‑catenin signaling pathway. The osteogenic differentiation of mesenchymal stem cells (MSCs) may be promoted by silent information regulator type‑1 [sirtuin (SIRT)1]. However, the molecular mechanism of SIRT1 regulation of osteogenic differentiation of MSCs remains unclear, and further elucidation is needed...
March 1, 2018: Molecular Medicine Reports
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