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Affandi T, Haas A, Ohm AM, Wright GM, Black JC, Reyland ME. PKCδ Regulates Chromatin Remodeling and DNA Repair through SIRT6. Mol Cancer Res 2024; 22:181-196. [PMID: 37889141 PMCID: PMC10872792 DOI: 10.1158/1541-7786.mcr-23-0493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 09/07/2023] [Accepted: 10/25/2023] [Indexed: 10/28/2023]
Abstract
Irradiation (IR) is a highly effective cancer therapy; however, IR damage to tumor-adjacent healthy tissues can result in significant comorbidities and potentially limit the course of therapy. We have previously shown that protein kinase C delta (PKCδ) is required for IR-induced apoptosis and that inhibition of PKCδ activity provides radioprotection in vivo. Here we show that PKCδ regulates histone modification, chromatin accessibility, and double-stranded break (DSB) repair through a mechanism that requires Sirtuin 6 (SIRT6). Overexpression of PKCδ promotes genomic instability and increases DNA damage and apoptosis. Conversely, depletion of PKCδ increases DNA repair via nonhomologous end joining (NHEJ) and homologous recombination (HR) as evidenced by increased formation of DNA damage foci, increased expression of DNA repair proteins, and increased repair of NHEJ and HR fluorescent reporter constructs. Nuclease sensitivity indicates that PKCδ depletion is associated with more open chromatin, while overexpression of PKCδ reduces chromatin accessibility. Epiproteome analysis reveals increased chromatin associated H3K36me2 in PKCδ-depleted cells which is accompanied by chromatin disassociation of KDM2A. We identify SIRT6 as a downstream mediator of PKCδ. PKCδ-depleted cells have increased SIRT6 expression, and depletion of SIRT6 reverses changes in chromatin accessibility, histone modification and DSB repair in PKCδ-depleted cells. Furthermore, depletion of SIRT6 reverses radioprotection in PKCδ-depleted cells. Our studies describe a novel pathway whereby PKCδ orchestrates SIRT6-dependent changes in chromatin accessibility to regulate DNA repair, and define a mechanism for regulation of radiation-induced apoptosis by PKCδ. IMPLICATIONS PKCδ controls sensitivity to irradiation by regulating DNA repair.
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Affiliation(s)
- Trisiani Affandi
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Ami Haas
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Angela M. Ohm
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Gregory M. Wright
- Department of Pharmacology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Joshua C. Black
- Department of Pharmacology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Mary E. Reyland
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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Zhao Z, Du J, Du Y, Gao Y, Yu M, Zhang Y, Fang H, Hou X. Deciphering the Allosteric Activation Mechanism of SIRT6 Using Molecular Dynamics Simulations. J Chem Inf Model 2023; 63:5896-5902. [PMID: 37653718 PMCID: PMC10530556 DOI: 10.1021/acs.jcim.3c00227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
As a member of the histone deacetylase protein family, the NAD+-dependent SIRT6 plays an important role in maintaining genomic stability and regulating cell metabolism. Interestingly, SIRT6 has been found to have a preference for hydrolyzing long-chain fatty acyls relative to deacetylation, and it can be activated by fatty acids. However, the mechanisms by which SIRT6 recognizes different substrates and can be activated by small molecular activators are still not well understood. In this study, we carried out extensive molecular dynamic simulations to shed light on these mechanisms. Our results revealed that the binding of the myristoylated substrate stabilizes the catalytically favorable conformation of NAD+, while the binding of the acetyl-lysine substrate leads to a loose binding of NAD+ in SIRT6. Based on these observations, we proposed a reasonable allosteric binding mode for myristic acid, which can enhance the catalytic activity of SIRT6 by stabilizing the binding of NAD+ with His131 as well as the acetylated substrate. Furthermore, our molecular dynamics simulations demonstrated that synthetic SIRT6 activators, such as UBCS039, MDL-801, and 12q, block the flipping of ribose in NAD+ and therefore can stabilize substrate-NAD+-His131 interactions in a manner similar to fatty acids. In summary, our newly proposed activation mechanism of SIRT6 highlights the importance of protein-substrate interactions, which would facilitate the rational design of new SIRT6 activators.
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Affiliation(s)
- Zhiyuan Zhao
- Department of Medicinal Chemistry and Key Laboratory of Chemical Biology of Natural Products (MOE), School of Pharmaceutical Science, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Jintong Du
- Department of Medicinal Chemistry and Key Laboratory of Chemical Biology of Natural Products (MOE), School of Pharmaceutical Science, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
- Shandong Cancer Hospital and Institute, Shandong First Medical University, Jinan, Shandong 250117, China
| | - Yu Du
- Department of Medicinal Chemistry and Key Laboratory of Chemical Biology of Natural Products (MOE), School of Pharmaceutical Science, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Yuan Gao
- Department of Medicinal Chemistry and Key Laboratory of Chemical Biology of Natural Products (MOE), School of Pharmaceutical Science, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Mingxuan Yu
- Department of Medicinal Chemistry and Key Laboratory of Chemical Biology of Natural Products (MOE), School of Pharmaceutical Science, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Yingkai Zhang
- Department of Chemistry, New York University, New York, NY 10003, United States
- Simons Center for Computational Physical Chemistry at New York University, New York, NY 10003, United States
| | - Hao Fang
- Department of Medicinal Chemistry and Key Laboratory of Chemical Biology of Natural Products (MOE), School of Pharmaceutical Science, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Xuben Hou
- Department of Medicinal Chemistry and Key Laboratory of Chemical Biology of Natural Products (MOE), School of Pharmaceutical Science, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
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Yang J, Chen X. SIRT6 attenuates LPS‐induced inflammation and apoptosis of lung epithelial cells in acute lung injury through ACE2/STAT3/PIM1 signaling. Immun Inflamm Dis 2023; 11:e809. [PMID: 36988243 PMCID: PMC10022422 DOI: 10.1002/iid3.809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 01/10/2023] [Accepted: 02/18/2023] [Indexed: 03/19/2023] Open
Abstract
Background Acute lung injury (ALI) is a severe and fatal respiratory disease. SIRT6 exerts pivotal activities in the process of lung diseases, but whether SIRT6 impacts ALI has not been covered. Methods Lentivirus recombinant expressing vector SIRT6 gene (Lent‐SIRT6) was constructed in mice, and there were control, lipopolysaccharide (LPS), LPS + Vehicle, and LPS + Lent SIRT6 groups. RT‐qPCR and western blot detected SIRT6 expression in lung tissues. HE staining observed pathological alternations in lung tissues. Wet‐to‐dry ratio of the lungs was then measured. The cell count of bronchoalveolar lavage fluid (BALF) was evaluated. Serum inflammation was examined with enzyme‐linked immunosorbent assay, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and western blot were to measure apoptosis. Western blot tested the expression of ACE2/STAT3/PIM1 signaling‐associated factors. At the cellular level, LPS was used to induce lung epithelial cells BEAS‐2B to establish cell injury models. SIRT6 was overexpressed and ACE2 expression was inhibited by cell transfection, and the mechanism of SIRT6 in LPS‐induced lung injury model was further explored by Cell Counting Kit‐8 (CCK‐8), western blot, quantitative reverse‐transcription polymerase chain reaction, TUNEL, and other techniques. Results The results of animal experiments showed that SIRT6 overexpression could reduce LPS‐induced lung pathological injury, pulmonary edema, and BALF cell ratio and attenuate LPS‐induced inflammatory response and cell apoptosis. In the above process, ACE2, STAT3, p‐STAT3, and PIM1 expression were affected. In cell experiments, SIRT6 expression was reduced in LPS‐induced BEAS‐2B cells. Inhibition of ACE2 expression could reverse the inhibitory effect of SIRT6 overexpression on ACE2/STAT3/PIM1 pathway, and cellular inflammatory response and apoptosis. Conclusion SIRT6 eased LPS‐evoked inflammation and apoptosis of lung epithelial cells in ALI through ACE2/STAT3/PIM1 signaling.
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Affiliation(s)
- Juan Yang
- Department of Pediatric, Shandong Provincial HospitalShandong UniversityJinanShandongChina
| | - Xing Chen
- Department of Pediatric, Shandong Provincial HospitalShandong UniversityJinanShandongChina
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Cai Y, Sheng Z, Chen Y, Wang J. LncRNA HMMR-AS1 promotes proliferation and metastasis of lung adenocarcinoma by regulating MiR-138/ sirt6 axis. Aging (Albany NY) 2020; 11:3041-3054. [PMID: 31128573 PMCID: PMC6555459 DOI: 10.18632/aging.101958] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 05/03/2019] [Indexed: 11/25/2022]
Abstract
Purpose: Long noncoding RNAs (lncRNA) play critical roles in cancer development. In this study, we aimed to explore the function and possible molecular mechanism of HMMR-AS1 involved in lung adenocarcinoma (LUAD). Experimental Design: Firstly, we analyzed HMMR-AS1 expression in LUAD tissues with the sequencing data from The Cancer Genome Atlas (TCGA). Next, we evaluated the effects of HMMR-AS1 on LUAD cell proliferation and apoptosis, and its regulation of miR-138 by acting as a ceRNA. The animal model was used to support the in vitro experimental findings. Results: HMMR-AS1 expression was significantly upregulated in LUAD tissues and was associated with larger tumor diameter, advanced TNM stage, lymph node metastasis, and shorter survival. Knockdown of HMMR-AS1 induced apoptosis and growth arrest in vitro and inhibited tumorigenesis in mouse xenografts. Mechanistically, HMMR-AS1 functioned as a ceRNA of miR-138, thereby leading to repression of its endogenous target sirt6. Moreover, knockdown of HMMR-AS1 dramatically inhibited tumor growth and metastasis of LUAD in vivo. Conclusions: Taken together, HMMR-AS1 is significantly over-expressed in LUAD, and HMMR-AS1–miR-138–sirt6 axis play a critical role in LUAD tumorigenesis. Our findings highlight an oncogenic role of HMMR-AS1 in LUAD.
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Affiliation(s)
- Yong Cai
- Department of Radiation Oncology, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China
| | - Zhaoying Sheng
- Department of Radiation Oncology, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China
| | - Yun Chen
- Department of Radiation Oncology, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China
| | - Jiying Wang
- Department of Oncology, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China
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Xiong X, Wang G, Tao R, Wu P, Kono T, Li K, Ding WX, Tong X, Tersey SA, Harris RA, Mirmira RG, Evans-Molina C, Dong XC. Sirtuin 6 regulates glucose-stimulated insulin secretion in mouse pancreatic beta cells. Diabetologia 2016; 59:151-160. [PMID: 26471901 PMCID: PMC4792692 DOI: 10.1007/s00125-015-3778-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 09/22/2015] [Indexed: 12/31/2022]
Abstract
AIMS/HYPOTHESIS Sirtuin 6 (SIRT6) has been implicated in ageing, DNA repair and metabolism; however, its function in pancreatic beta cells is unclear. The aim of this study is to elucidate the role of SIRT6 in pancreatic beta cells. METHODS To investigate the function of SIRT6 in pancreatic beta cells, we performed Sirt6 gene knockdown in MIN6 cells and generated pancreatic- and beta cell-specific Sirt6 knockout mice. Islet morphology and glucose-stimulated insulin secretion (GSIS) were analysed. Glycolysis and oxygen consumption rates in SIRT6-deficient beta cells were measured. Cytosolic calcium was monitored using the Fura-2-AM fluorescent probe (Invitrogen, Grand Island, NY, USA). Mitochondria were analysed by immunoblots and electron microscopy. RESULTS Sirt6 knockdown in MIN6 beta cells led to a significant decrease in GSIS. Pancreatic beta cell Sirt6 knockout mice showed a ~50% decrease in GSIS. The knockout mouse islets had lower ATP levels compared with the wild-type controls. Mitochondrial oxygen consumption rates were significantly decreased in the SIRT6-deficient beta cells. Cytosolic calcium dynamics in response to glucose or potassium chloride were attenuated in the Sirt6 knockout islets. Numbers of damaged mitochondria were increased and mitochondrial complex levels were decreased in the SIRT6-deficient islets. CONCLUSIONS/INTERPRETATION These data suggest that SIRT6 is important for GSIS from pancreatic beta cells and activation of SIRT6 may be useful to improve insulin secretion in diabetes.
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Affiliation(s)
- Xiwen Xiong
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS1021D, Indianapolis, IN, 46202, USA
| | - Gaihong Wang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS1021D, Indianapolis, IN, 46202, USA
| | - Rongya Tao
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS1021D, Indianapolis, IN, 46202, USA
| | - Pengfei Wu
- Richard Roudebush Veterans Affairs Medical Center, Indianapolis, IN, USA
| | - Tatsuyoshi Kono
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Kevin Li
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS, USA
| | - Wen-Xing Ding
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS, USA
| | - Xin Tong
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Sarah A Tersey
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Robert A Harris
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS1021D, Indianapolis, IN, 46202, USA
- Richard Roudebush Veterans Affairs Medical Center, Indianapolis, IN, USA
| | - Raghavendra G Mirmira
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Carmella Evans-Molina
- Richard Roudebush Veterans Affairs Medical Center, Indianapolis, IN, USA
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - X Charlie Dong
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS1021D, Indianapolis, IN, 46202, USA.
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Marquardt JU, Fischer K, Baus K, Kashyap A, Ma S, Krupp M, Linke M, Teufel A, Zechner U, Strand D, Thorgeirsson SS, Galle PR, Strand S. Sirtuin-6-dependent genetic and epigenetic alterations are associated with poor clinical outcome in hepatocellular carcinoma patients. Hepatology 2013; 58:1054-64. [PMID: 23526469 PMCID: PMC3759627 DOI: 10.1002/hep.26413] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 03/15/2013] [Indexed: 12/12/2022]
Abstract
UNLABELLED Sirtuin 6 (SIRT6) is a member of the sirtuin family of NAD+-dependent deacetylases. Genetic deletion of Sirt6 in mice results in a severe degenerative phenotype with impaired liver function and premature death. The role of SIRT6 in development and progression of hepatocellular carcinoma is currently unknown. We first investigated SIRT6 expression in 153 primary human liver cancers and in normal and cirrhotic livers using microarray analysis. SIRT6 was significantly down-regulated in both cirrhotic livers and cancer. A Sirt6 knockout (KO) gene expression signature was generated from primary hepatoctyes isolated from 3-week-old Sirt6-deficient animals. Sirt6-deficient hepatocytes showed up-regulation of established hepatocellular carcinoma (HCC) biomarkers alpha-fetoprotein (Afp), insulin-like growth factor 2 (Igf2), H19, and glypican-3. Furthermore, decreased SIRT6 expression was observed in hepatoma cell lines that are known to be apoptosis-insensitive. Re-expression of SIRT6 in HepG2 cells increased apoptosis sensitivity to CD95-stimulation or chemotherapy treatment. Loss of Sirt6 was characterized by oncogenic changes, such as global hypomethylation, as well as metabolic changes, such as hypoglycemia and increased fat deposition. The hepatocyte-specific Sirt6-KO signature had a prognostic impact and was enriched in patients with poorly differentiated tumors with high AFP levels as well as recurrent disease. Finally, we demonstrated that the Sirt6-KO signature possessed a predictive value for tumors other than HCC (e.g., breast and lung cancer). CONCLUSION Loss of SIRT6 induces epigenetic changes that may be relevant to chronic liver disease and HCC development. Down-regulation of SIRT6 and genes dysregulated by loss of SIRT6 possess oncogenic effects in hepatocarcinogenesis. Our data demonstrate that deficiency in one epigenetic regulator predisposes a tumorigenic phenotype that ultimately has relevance for outcome of HCC and other cancer patients.
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Affiliation(s)
- Jens U. Marquardt
- I. Department of Internal Medicine, University Medical Center, Johannes Gutenberg University Mainz, Germany,Laboratory of Experimental Carcinogenesis, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland, USA
| | - Kerstin Fischer
- I. Department of Internal Medicine, University Medical Center, Johannes Gutenberg University Mainz, Germany
| | - Katharina Baus
- I. Department of Internal Medicine, University Medical Center, Johannes Gutenberg University Mainz, Germany
| | - Anubha Kashyap
- I. Department of Internal Medicine, University Medical Center, Johannes Gutenberg University Mainz, Germany
| | - Shengyun Ma
- I. Department of Internal Medicine, University Medical Center, Johannes Gutenberg University Mainz, Germany
| | - Markus Krupp
- I. Department of Internal Medicine, University Medical Center, Johannes Gutenberg University Mainz, Germany
| | - Matthias Linke
- Institute of Human Genetics, University Medical Center, Johannes Gutenberg University Mainz, Germany
| | - Andreas Teufel
- I. Department of Internal Medicine, University Medical Center, Johannes Gutenberg University Mainz, Germany
| | - Ulrich Zechner
- Institute of Human Genetics, University Medical Center, Johannes Gutenberg University Mainz, Germany
| | - Dennis Strand
- I. Department of Internal Medicine, University Medical Center, Johannes Gutenberg University Mainz, Germany
| | - Snorri S. Thorgeirsson
- Laboratory of Experimental Carcinogenesis, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland, USA
| | - Peter R. Galle
- I. Department of Internal Medicine, University Medical Center, Johannes Gutenberg University Mainz, Germany
| | - Susanne Strand
- I. Department of Internal Medicine, University Medical Center, Johannes Gutenberg University Mainz, Germany,Corresponding author: Susanne Strand, PhD, I. Department of Internal Medicine, Molecular Hepatology, University Medical Center, Johannes Gutenberg University Mainz, Obere Zahlbacherstraße 63, 55131 Mainz, Germany, Phone: +49 6131 179782, Fax: +49 6131 179963,
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Van Meter M, Mao Z, Gorbunova V, Seluanov A. Repairing split ends: SIRT6, mono-ADP ribosylation and DNA repair. Aging (Albany NY) 2011; 3:829-835. [PMID: 21946623 PMCID: PMC3227448 DOI: 10.18632/aging.100389] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 09/22/2011] [Indexed: 05/31/2023]
Abstract
The sirtuin gene family comprises an evolutionarily ancient set of NAD+ dependent protein deacetylase and mono-ADP ribosyltransferase enzymes. Found in all domains of life, sirtuins regulate a diverse array of biological processes, including DNA repair, gene silencing, apoptosis and metabolism. Studies in multiple model organisms have indicated that sirtuins may also function to extend lifespan and attenuate age-related pathologies. To date, most of these studies have focused on the deacetylase activity of sirtuins, and relatively little is known about the other biochemical activity of sirtuins, mono-ADP ribosylation. We recently reported that the mammalian sirtuin, SIRT6, mono-ADP ribosylates PARP1 to promote DNA repair in response to oxidative stress. In this research perspective we review the role of SIRT6 in DNA repair and discuss the emerging implications for sirtuin directed mono-ADP ribosylation in aging and age-related diseases.
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Affiliation(s)
- Michael Van Meter
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
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Kim HS, Xiao C, Wang RH, Lahusen T, Xu X, Vassilopoulos A, Vazquez-Ortiz G, Jeong WI, Park O, Ki SH, Gao B, Deng CX. Hepatic-specific disruption of SIRT6 in mice results in fatty liver formation due to enhanced glycolysis and triglyceride synthesis. Cell Metab 2010; 12:224-36. [PMID: 20816089 PMCID: PMC2935915 DOI: 10.1016/j.cmet.2010.06.009] [Citation(s) in RCA: 374] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 04/01/2010] [Accepted: 06/03/2010] [Indexed: 12/27/2022]
Abstract
Under various conditions, mammals have the ability to maintain serum glucose concentration within a narrow range. SIRT1 plays an important role in regulating gluconeogenesis and fat metabolism; however, the underlying mechanisms remain elusive. Here, we show that SIRT1 forms a complex with FOXO3a and NRF1 on the SIRT6 promoter and positively regulates expression of SIRT6, which, in turn, negatively regulates glycolysis, triglyceride synthesis, and fat metabolism by deacetylating histone H3 lysine 9 in the promoter of many genes involved in these processes. Liver-specific deletion of SIRT6 in mice causes profound alterations in gene expression, leading to increased glycolysis, triglyceride synthesis, reduced beta oxidation, and fatty liver formation. Human fatty liver samples exhibited significantly lower levels of SIRT6 than did normal controls. Thus, SIRT6 plays a critical role in fat metabolism and may serve as a therapeutic target for treating fatty liver disease, the most common cause of liver dysfunction in humans.
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Affiliation(s)
- Hyun-Seok Kim
- Genetics of Development and Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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