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Hobson S, Arefin S, Witasp A, Hernandez L, Kublickiene K, Shiels PG, Stenvinkel P. Accelerated Vascular Aging in Chronic Kidney Disease: The Potential for Novel Therapies. Circ Res 2023; 132:950-969. [PMID: 37053277 DOI: 10.1161/circresaha.122.321751] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [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] [Indexed: 04/15/2023]
Abstract
The pathophysiology of vascular disease is linked to accelerated biological aging and a combination of genetic, lifestyle, biological, and environmental risk factors. Within the scenario of uncontrolled artery wall aging processes, CKD (chronic kidney disease) stands out as a valid model for detailed structural, functional, and molecular studies of this process. The cardiorenal syndrome relates to the detrimental bidirectional interplay between the kidney and the cardiovascular system. In addition to established risk factors, this group of patients is subjected to a plethora of other emerging vascular risk factors, such as inflammation, oxidative stress, mitochondrial dysfunction, vitamin K deficiency, cellular senescence, somatic mutations, epigenetic modifications, and increased apoptosis. A better understanding of the molecular mechanisms through which the uremic milieu triggers and maintains early vascular aging processes, has provided important new clues on inflammatory pathways and emerging risk factors alike, and to the altered behavior of cells in the arterial wall. Advances in the understanding of the biology of uremic early vascular aging opens avenues to novel pharmacological and nutritional therapeutic interventions. Such strategies hold promise to improve future prevention and treatment of early vascular aging not only in CKD but also in the elderly general population.
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Affiliation(s)
- S Hobson
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden (S.H., S.A., A.W., L.H., K.K., P.S.)
| | - S Arefin
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden (S.H., S.A., A.W., L.H., K.K., P.S.)
| | - A Witasp
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden (S.H., S.A., A.W., L.H., K.K., P.S.)
| | - L Hernandez
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden (S.H., S.A., A.W., L.H., K.K., P.S.)
| | - K Kublickiene
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden (S.H., S.A., A.W., L.H., K.K., P.S.)
| | - P G Shiels
- School of Molecular Biosciences, MVLS, University of Glasgow, United Kingdom (P.G.S.)
| | - P Stenvinkel
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden (S.H., S.A., A.W., L.H., K.K., P.S.)
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Mafra D, Borges NA, Alvarenga L, Ribeiro M, Fonseca L, Leal VO, Shiels PG, Stenvinkel P. Fermented food: Should patients with cardiometabolic diseases go back to an early neolithic diet? Crit Rev Food Sci Nutr 2022; 63:10173-10196. [PMID: 35593230 DOI: 10.1080/10408398.2022.2077300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Fermentation has been used since the Early Neolithic period to preserve foods. It has inherent organoleptic and nutritive properties that bestow health benefits, including reducing inflammation and oxidative stress, supporting the growth of salutogenic microbiota, enhancing intestinal mucosal protection and promoting beneficial immunometabolic health effects. The fermentation of food with specific microbiota increases the production salutogenic bioactive compounds that can activate Nrf2 mediated cytoprotective responses and mitigate the effects of the 'diseasome of aging' and its associated inflammageing, which presents as a prominent feature of obesity, type-2 diabetes, cardiovascular and chronic kidney disease. This review discusses the importance of fermented food in improving health span, with special reference to cardiometabolic diseases.
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Affiliation(s)
- D Mafra
- Post Graduation Program in Medical Sciences, Federal Fluminense University, Niterói-Rio de Janeiro, Brazil
- Graduate Program in Biological Sciences, Physiology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - N A Borges
- Institute of Nutrition, University of the State of Rio de Janeiro, Rio de Janeiro, Brazil
| | - L Alvarenga
- Post Graduation Program in Medical Sciences, Federal Fluminense University, Niterói-Rio de Janeiro, Brazil
| | - M Ribeiro
- Graduate Program in Biological Sciences, Physiology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - L Fonseca
- Post Graduation Program in Medical Sciences, Federal Fluminense University, Niterói-Rio de Janeiro, Brazil
| | - V O Leal
- Division of Nutrition, Pedro Ernesto University Hospital, University of the State of Rio de Janeiro, Rio de Janeiro, Brazil
| | - P G Shiels
- Wolfson Wohl Translational Research Centre, University of Glasgow, Bearsden, Glasgow, UK
| | - P Stenvinkel
- Division of Renal Medicine, Department of Clinical Science, Technology and Intervention, Karolinska Instituted, Stockholm, Sweden
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Stenvinkel P, Painer J, Shiels PG, Bansal A, Fereidouni S, Natterson-Horowitz B, Johnson RJ, Miranda JJ. SARS-COV-2 and biomimetics: What saves the planet will save our health. J Intern Med 2021; 289:244-246. [PMID: 32583447 PMCID: PMC7361468 DOI: 10.1111/joim.13128] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 05/29/2020] [Indexed: 12/26/2022]
Affiliation(s)
- P Stenvinkel
- From the, Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institute, Stockholm, Sweden
| | - J Painer
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria
| | - P G Shiels
- Wolfson Wohl Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
| | - A Bansal
- Division of Renal Diseases, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - S Fereidouni
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria
| | - B Natterson-Horowitz
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA.,Evolutionary Medicine Program, University of California, Los Angeles, CA, USA
| | - R J Johnson
- Division of Renal Diseases, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - J J Miranda
- School of Medicine, Universidad Peruana Cayetano Heredia, Lima, Peru
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O'Toole PW, Shiels PG. The role of the microbiota in sedentary lifestyle disorders and ageing: lessons from the animal kingdom. J Intern Med 2020; 287:271-282. [PMID: 31957113 DOI: 10.1111/joim.13021] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [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: 11/04/2019] [Revised: 12/19/2019] [Accepted: 01/08/2020] [Indexed: 02/06/2023]
Abstract
A paradox of so-called developed countries is that, as the major historical causes of human mortality are eliminated or mitigated by medical progress, lifestyle-related diseases have become major killers. Furthermore, as lifespan is extended by the combined effects of modern medicine, health span is struggling to keep apace because of the burden of noncommunicable diseases linked to diet and sedentary lifestyle. The gut microbiome is now recognized as a plastic environmental risk factor for many of these diseases, the microbiome being defined as the complex community of co-evolved commensal microbes that breaks down components of a complex diet, modulates innate immunity, and produces signalling molecules and metabolites that can impact on diverse regulatory systems in mammals. Aspects of the so-called 'Western' lifestyle linked to disease risk such as energy dense diet and antibiotic treatment are known to affect the composition and function of the microbiome. Here, we review the detailed mechanisms whereby the gut microbiome may modulate risk of diseases linked to sedentary lifestyle and ageing-related health loss. We focus on the comparative value of natural animal models such as hibernation for studying metabolic regulation and the challenge of extrapolating from animal models to processes that occur in human ageing.
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Affiliation(s)
- P W O'Toole
- From the, School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - P G Shiels
- Wolfson Wohl Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
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Stevenson RP, Shapter O, Aitken E, Stevenson K, Shiels PG, Kingsmore DB. Has the Expansion in Extended Criteria Deceased Donors Led to a Different Type of Delayed Graft Function and Poorer Outcomes? Transplant Proc 2019; 50:3160-3164. [PMID: 30577182 DOI: 10.1016/j.transproceed.2018.07.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 06/27/2018] [Accepted: 07/09/2018] [Indexed: 11/30/2022]
Abstract
OBJECTIVES There has been considerable change in the practice of deceased kidney transplantation in the past 15 years, with more extreme phenotypes implanted. The aim of this study was to determine whether increased use of expanded criteria donors (extended criteria donors and donors after circulatory death) affected clinical outcomes, including the incidence and pattern of delayed graft function. METHODS AND MATERIALS A retrospective analysis of 1359 renal transplants was performed over 15 years. The first 10 years of data (group 1) were compared with the subsequent 5 years (group 2). Outcomes were analyzed at 6 months and 12 months in addition to serum creatinine and patterns of delayed graft function (posttransplant times: on hemodialysis, to peak creatinine, for creatinine to half, and for creatinine to fall within 10% of baseline). RESULTS There was a significant increase in the percentage of expanded criteria donor allografts used in group 2 with a significant increase in the incidence of delayed graft function. Despite this, serum creatinine and the incidence of biopsy-proven acute rejection had both improved in group 2. Group 2 expanded criteria donor kidneys had a significantly lower incidence of type 1 delayed graft function and a significantly higher incidence of types 3 and 4 delayed graft function. Time for creatinine to half in both groups was the best predictor of a serum creatinine <180 μmol/L at 1 year. CONCLUSION The increased use of expanded criteria donor kidneys has led to a higher incidence of delayed graft function, but the pattern has shown that the requirement for hemodialysis has significantly reduced.
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Affiliation(s)
- R P Stevenson
- Department of Renal Surgery, Queen Elizabeth University Hospital, Glasgow, United Kingdom.
| | - O Shapter
- Department of Renal Surgery, Queen Elizabeth University Hospital, Glasgow, United Kingdom
| | - E Aitken
- Department of Renal Surgery, Queen Elizabeth University Hospital, Glasgow, United Kingdom
| | - K Stevenson
- Department of Renal Surgery, Queen Elizabeth University Hospital, Glasgow, United Kingdom
| | - P G Shiels
- Institute of Cancer Sciences, Wolfson Wohl Building, Garscube Estate, Bearsden, Glasgow, United Kingdom
| | - D B Kingsmore
- Department of Renal Surgery, Queen Elizabeth University Hospital, Glasgow, United Kingdom
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Vazirpanah N, Kienhorst LBE, Van Lochem E, Wichers C, Rossato M, Shiels PG, Dalbeth N, Stamp LK, Merriman TR, Janssen M, Radstake TRDJ, Broen JC. Patients with gout have short telomeres compared with healthy participants: association of telomere length with flare frequency and cardiovascular disease in gout. Ann Rheum Dis 2017; 76:1313-1319. [PMID: 28347991 DOI: 10.1136/annrheumdis-2016-210538] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [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: 09/15/2016] [Revised: 01/31/2017] [Accepted: 03/02/2017] [Indexed: 01/12/2023]
Abstract
AIM AND BACKGROUND Chronic inflammation associates with increased senescence, which is a strong predictor for cardiovascular disease. We hypothesised that inflammation accelerates senescence and thereby enhances the risk of cardiovascular disease in gout. METHODS We assessed replicative senescence by quantifying telomere length (TL) in a discovery cohort of 145 Dutch patients with gout and 273 healthy individuals and validated our results in 474 patients with gout and 293 healthy participants from New Zealand. Subsequently, we investigated the effect of cardiovascular disease on TL of all participants. Also, we measured TL of CD4+ and CD8+ T lymphocytes, B lymphocytes, monocytes, natural killer cells and plasmacytoid dendritic cells. Additionally, we assessed the potential temporal difference in TL and telomerase activity. RESULTS TL in PBMCs of healthy donors decreased over time, reflecting normal ageing. Patients with gout demonstrated shorter telomeres (p=0.001, R2=0.01873). In fact, the extent of telomere erosion in patients with gout was higher at any age compared with healthy counterparts at any age (p<0.0001, R2=0.02847). Patients with gout with cardiovascular disease had the shortest telomeres and TL was an independent risk factor for cardiovascular disease in patients with gout (p=0.001). TL was inversely associated with the number of gouty flares (p=0.005). CONCLUSIONS Patients with gout have shorter telomeres than healthy participants, reflecting increased cellular senescence. Telomere shortening was associated with the number of flares and with cardiovascular disease in people with gout.
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Affiliation(s)
- N Vazirpanah
- Department of Rheumatology and Clinical Immunology, University Medical Centre Utrecht, Utrecht, The Netherlands.,Laboratory of Translational Immunology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - L B E Kienhorst
- Department of Dermatology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - E Van Lochem
- Department of Medical Microbiology and Immunology, Rijnstate Hospital, Arnhem, The Netherlands
| | - C Wichers
- Department of Rheumatology and Clinical Immunology, University Medical Centre Utrecht, Utrecht, The Netherlands.,Laboratory of Translational Immunology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - M Rossato
- Department of Rheumatology and Clinical Immunology, University Medical Centre Utrecht, Utrecht, The Netherlands.,Laboratory of Translational Immunology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - P G Shiels
- University of Glasgow, Institute of Cancer Sciences, Wolfson-Wohl Translational Cancer Research Centre, Glasgow, UK
| | - N Dalbeth
- University of Auckland, Auckland, New Zealand
| | - L K Stamp
- University of Otago, Christchurch, New Zealand
| | | | - M Janssen
- Department of Medical Microbiology and Immunology, Rijnstate Hospital, Arnhem, The Netherlands
| | - T R D J Radstake
- Department of Rheumatology and Clinical Immunology, University Medical Centre Utrecht, Utrecht, The Netherlands.,Laboratory of Translational Immunology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - J Ca Broen
- Department of Rheumatology and Clinical Immunology, University Medical Centre Utrecht, Utrecht, The Netherlands.,Laboratory of Translational Immunology, University Medical Centre Utrecht, Utrecht, The Netherlands
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Shiels PG, Kind AJ, Campbell KH, Wilmut I, Waddington D, Colman A, Schnieke AE. Analysis of telomere length in Dolly, a sheep derived by nuclear transfer. ACTA ACUST UNITED AC 2015; 1:119-25. [PMID: 16218837 DOI: 10.1089/15204559950020003] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We have used a (TTAGGG) oligonucleotide probe to demonstrate that ovine telomeres are composed of (TTAGGG) repeat arrays and to compare the terminal restriction fragment lengths of sheep derived by natural mating and nuclear transfer. Here we show that ovine somatic telomeres decrease in length with age, and that Dolly, derived by the transfer of 6-year-old adult somatic nucleus, exhibits diminished terminal restriction fragment lengths. The decrease is consistent with the age of the donor tissue and telomere erosion during in vitro culture. Nuclear transfer does not restore telomere lengths. Dolly otherwise appears physiologically and phenotypically normal for her breed and age. We further report on apparent telomere lengthening in sheep, occurring during the first year in naturally derived lambs.
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Affiliation(s)
- P G Shiels
- PPL Therapeutics, Roslin, Midlothian, Scotland
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Rabinovich RA, Choudhury G, Lahkdar R, Drost EM, McGlynn L, Bai J, Shiels PG, Miller BE, Tal-Singer R, Agusti A, MacNee W. S49 Telomere Attrition In Circulating White Blood Cells In Copd Relates To Lung Function And Outcomes. Thorax 2014. [DOI: 10.1136/thoraxjnl-2014-206260.55] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Lemoine S, Fournier T, Kocevar G, Belloi A, Ibarrola D, Sappey-Marinier D, Juillard L, Kaysen G, Usvyat L, Grassmann A, Marcelli D, Pecoits-Filho R, Marelli C, Kooman J, Van Der Sande F, Haviv Y, Power A, Kotanko P, Migliori M, Cantaluppi V, Medica D, Paoletti S, Panichi V, Kuragano T, Yahiro M, Kida A, Nagasawa Y, Hasuike Y, Nanami M, Nakanishi T, Garneata L, Slusanschi O, Dragomir DR, Corbu-Stancu A, Barbulescu C, Mircescu G, Minutolo R, Borrelli S, De Nicola L, Conte G, Basic-Jukic N, Katalinic L, Ivandic E, Kes P, Jelakovic B, Beberashvili I, Sinuani I, Azar A, Shapiro G, Feldman L, Stav K, Sandbank J, Averbukh Z, Bruschetta E, Righetti M, Colombo F, Palmieri N, Prencipe M, Bracchi O, Stefani F, Amar K, Scalia A, Conte F, Rosenberger J, Majernikova M, Kissova V, Straussova Z, Boldizsar J, Cobo G, Di Gioia C, Camacho R, Garcia Lacalle C, Ortega O, Rodriguez I, Mon C, Ortiz M, Herrero J, Oliet A, Vigil A, Gallar P, Kyriazis J, Markaki A, Kourtesi K, Kalymniou M, Vougazianos S, Kyriazis P, Stylianou K, Tanaka H, Tsuneyoshi S, Sawa M, Fujisaki K, Daijo Y, Hristea D, Paris A, Lefrancois G, Volteau C, Savoiu C, Ozenne S, Testa A, Coupel S, Bertho I, Legall MC, Magnard J, Deschamps T, Capusa C, Stoian I, Barbulescu C, Santimbrean C, Dumitru D, Mircescu G, Kato S, Lindholm B, Yuzawa Y, Shiels PG, Hwang JC, Jiang MY, Lu YH, Wang CT, Chiou TTY, Lee YT, Ng HY, Lee CT, Kaminska D, Koscielska-Kasprzak K, Chudoba P, Mazanowska O, Zabinska M, Banasik M, Boratynska M, Lepiesza A, Korta K, Klinger M, Struijk-Wielinga T, Neelemaat F, Slieker T, Koolen M, Ter Wee PM, Weijs PJ\, Tsuchida K, Hirose D, Minakuchi J, Kawashima S, Tomo T, Lee JE, Yun GY, Choi HY, Lee S, Kim W, Jo IY, Ha SK, Kim HJ, Park HC, Migliori M, Scatena A, Cantaluppi V, Rosati A, Pizzarelli F, Panichi V, Shin BC, Kim HL, Chung JH, Malgorzewicz S, Chmmielewski M, Debska-Slizien A, Rutkowski B, Kolesnyk M, Stepanova N, Korol L, Kulizkyi M, Ablogina O, Migal L, Takahashi T, Kitajima Y, Hirano S, Naka A, Ogawa H, Aono M, Sato Y, Hoppe K, Schwermer K, K Ysz P, Kaczmarek J, Baum E, Sikorska D, Radziszewska D, Szkudlarek M, Olejniczak P, Pawlaczyk K, Lindholm B, Oko A, Severova Andreevska G, Trajceska L, Gelev S, Dzekova P, Selim G, Sikole A, Trajceska L, Severova Andreevska G, Rambabova Busletik I, Gelev S, Pavleska Kuzmanovska S, Dzekova Vidimiski P, Selim G, Sikole A, Borrelli S, De Simone E, Laurino S, De Simone W, Ahbap E, Kara E, Basturk T, Sakaci T, Koc Y, Sahutoglu T, Akgol C, Sevinc M, Atan Ucar Z, Unsal A, Girndt M, Fiedler R, Martus P, Pawlak M, Storr M, Boehler T, Templin M, Trojanowicz B, Ulrich C, Glomb M, Liehr K, Werner K, Zickler D, Schindler R, Vishnevskii KA, Gerasimchuk RP, Zemchenkov AY, Moura A, Madureira J, Alija P, Fernandes JC, Oliveira JG, Lopez M, Filgueiras M, Amado L, Sameiro-Faria M, Miranda V, Vieira M, Santos-Silva A, Costa E, Zaluska W, Kotlinska-Hasiec EKH, Zaluska A, Rzecki Z, Zadora P, Dabrowski W, Sikole A, Trajceska L, Amitov V, Busletik IR, Dzekova P, Selim G, Severova Andreevska G, Gelev S, Aicardi Spalloni V, La Milia V, Longhi S, Volo L, Del Vecchio L, Pontoriero G, Locatelli F, Martino F, Scalzotto E, Corradi V, Nalesso F, Zanella M, Brandolan A, Perez De Jose A, Abad S, Vega A, Reque J, Quiroga B, Lopez-Gomez JM, Esteve Simo V, Duarte Gallego V, Moreno Guzman F, Fulquet Nicolas M, Pou Potau M, Saurina Sole A, Carneiro Oliveira J, Ramirez De Arellano Serna M, Ahbap E, Kara E, Basturk T, Koc Y, Sakaci T, Sahutoglu T, Sevinc M, Atan Ucar Z, Unsal A, Van Diepen AT, Hoekstra T, De Mutsert R, Rotmans JI, De Boer M, Suttorp MM, Struijk DG, Boeschoten EW, Krediet RT, Dekker FW, Trigka K, Chouchoulis K, Musso CG, Kaza M, Mpimpi A, Pipili C, Kyritsis I, Douzdampanis P, Streja E, Rezakhani S, Rhee CM, Kalantar-Zadeh K, Streja E, Doshi M, Rhee C, Kovesdy C, Moradi H, Kalantar-Zadeh K, Dantas MA, Resende LL, Silva LF, Matos CM, Lopes GB, Lopes AA, Knap B, Arnol M, Buturovic J, Ponikvar R, Bren A, Codognotto M, Piasentin P, Conte F, Righetti M, Limido A, Tsuchida K, Michiwaki H, Minakuchi J, Kawashima S, Tomo T, Mutsaers HA, Jansen J, Van Den Broek PH, Verweij VG, Van Den Heuvel LP, Hoenderop JG, Masereeuw R, Clari R, Mongilardi E, Vigotti FN, Scognamiglio S, Consiglio V, Nazha M, Avagnina P, Piccoli G, Costelloe SJ, Freeman J, Keane DF, Lindley EJ, Thompson D, Kang GW, Lee IH, Ahn KS. DIALYSIS. PROTEIN-ENERGY WASTING, INFLAMMATION AND OXIDATIVE STRESS. Nephrol Dial Transplant 2014. [DOI: 10.1093/ndt/gfu159] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Abstract
The Sirtuins are a family of orthologues of yeast Sir2 found in a wide range of organisms from bacteria to man. They display a high degree of conservation between species, in both sequence and function, indicative of their key biochemical roles. Sirtuins are heavily implicated in cell cycle, cell division, transcription regulation, and metabolism, which places the various family members at critical junctures in cellular metabolism. Typically, Sirtuins have been implicated in the preservation of genomic stability and in the prolongation of lifespan though many of their target interactions remain unknown.
Sirtuins play key roles in tumourigenesis, as some have tumour-suppressor functions and others influence tumours through their control of the metabolic state of the cell. Their links to ageing have also highlighted involvement in various age-related and degenerative diseases. Here, we discuss the current understanding of the role of Sirtuins in age-related diseases while taking a closer look at their roles and functions in maintaining genomic stability and their influence on telomerase and telomere function.
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Affiliation(s)
- D McGuinness
- College of Medical, Veterinary and Life Sciences, Institute of Cancer Sciences, University of Glasgow, Glasgow G11 6NT, Scotland, UK
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Affiliation(s)
- K Stevenson
- University of Glasgow, Div. Cancer Sciences and Mol. Pathology, Dept. of Surgery, Glasgow Royal Infirmary, 10 Alexandra Parade, Glasgow G31 2ER UK
| | - L McGlynn
- University of Glasgow, Div. Cancer Sciences and Mol. Pathology, Dept. of Surgery, Glasgow Royal Infirmary, 10 Alexandra Parade, Glasgow G31 2ER UK
| | - PG Shiels
- University of Glasgow, Div. Cancer Sciences and Mol. Pathology, Dept. of Surgery, Glasgow Royal Infirmary, 10 Alexandra Parade, Glasgow G31 2ER UK
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Zino S, Moran CP, McGlynn LM, George W, Payne AP, Shiels PG. SIRT7 expression and epigenetic status determine variability in telomere length in breast cancer. Cancer Res 2009. [DOI: 10.1158/0008-5472.sabcs-4052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Abstract #4052
Background: As cancer is a disease of ageing, factors involved in biological ageing may be informative in investigating the underlying mechanisms of cancer pathogenesis. How biological age is affected by epigenetic changes remains to be fully determined. This is pertinent to cancer pathogenesis, as epigenetic changes can increase the risk of neoplasia. We have investigated the biological age of breast tumours, using telomere length and the expression of sirtuin 7, a gene involved in the regulation of ribosome biosynthesis and previously demonstrated as potentially prognostic in breast cancer. We have evaluated these for association with epigenetic status.
 Materials and Methods: Telomere lengths and Sirtuin 7 (SIRT7) expression were determined using Q-PCR. Epigenetic status was determined using a Methylamp Global DNA methylation kit. Statistical analysis was performed using SPSS v15.
 Results: Chronological age was negatively associated with telomere length (p=0.013) and positively associated with methylation levels (p=0.007). Furthermore, telomere length showed a negative association with global methylation levels (p=0.002). Individuals with shorter telomeres were older and demonstrated higher levels of global DNA methylation. SIRT7 expression was positively associated with telomere length (p=0.01), but showed no association with methylation levels. Linear regression analysis indicated that SIRT7 expression accounted for 52.2% of the observed variability in telomere length (p=0.001) and methlyation for 33.4% (p<0.001). Multiple linear regression analysis indicated that methylation status and SIRT7 expression combined accounted for 69.4% of the observed variability in telomere length. Chronological age was not a significant contributor in either analysis.
 Discussion: Cells with critically short telomeres present a high risk of becoming neoplastic, as they are biologically aged. This study has demonstrated that both SIRT7 expression and global methylation levels significantly influence telomere attrition in breast cancer. This is consistent with a scenario whereby the rate of biological ageing in breast tumours is influenced by telomere mediated epigenetic changes and mechanistically by cellular proliferation requirements. The latter is manifest through SIRT7 regulated ribosome biogenesis. These findings support the use of SIRT7 as a potential prognostic tool and therapeutic target in breast cancer.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4052.
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Affiliation(s)
- S Zino
- 1 Surgery, Glasgow Uni., Glasgow, United Kingdom
| | - CP Moran
- 1 Surgery, Glasgow Uni., Glasgow, United Kingdom
| | - LM McGlynn
- 1 Surgery, Glasgow Uni., Glasgow, United Kingdom
| | - W George
- 1 Surgery, Glasgow Uni., Glasgow, United Kingdom
| | - AP Payne
- 2 FBLS, Glasgow Uni, Glasgow, United Kingdom
| | - PG Shiels
- 1 Surgery, Glasgow Uni., Glasgow, United Kingdom
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MacIntyre A, Brouilette SW, Lamb K, Radhakrishnan K, McGlynn L, Chee MM, Parkinson EK, Freeman D, Madhok R, Shiels PG. Association of increased telomere lengths in limited scleroderma, with a lack of age-related telomere erosion. Ann Rheum Dis 2008; 67:1780-2. [PMID: 18662931 DOI: 10.1136/ard.2007.086652] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES Telomere erosion, a feature of biological ageing, is implicated in a wide range of diseases. Its impact on autoimmune diseases remains unclear although autoantibodies against many telomere nucleoprotein components are prevalent in these diseases. We aimed to assess if telomere biology was abnormal in a cohort of patients with limited cutaneous systemic sclerosis (lcSSc). METHODS Telomere lengths in peripheral blood leucocytes (PBL) were determined using Southern blotting methods in a cohort of lcSSc subjects (n=43; age range 37-80 years) and a control population (n=107; age range 21-65 years). RESULTS Telomere lengths in lcSSc subjects were longer than controls (p<0.001), did not show age-related telomere erosion and differed significantly from age-matched controls only after 50 years of age (p<0.001). CONCLUSIONS This is the first report of maintenance of telomere lengths in an autoimmune disease state. These data indicate aberrant telomere biology and irregular biological ageing from the fifth decade of life. These findings provide insight into compromised DNA damage repair in lcSSc. Whether these observations indicate a causal or consequential relationship requires further investigation. This in turn, may provide potential novel targets for therapeutic intervention.
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Affiliation(s)
- A MacIntyre
- Division of Cancer Sciences and Molecular Pathology, University of Glasgow, Glasgow Royal Infirmary, Glasgow G31 2ER, UK
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14
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Stevenson KS, Radhakrishnan K, Patterson CS, McMillan LC, Skeldon KD, Buist L, Padgett MJ, Shiels PG. Breath ethane peaks during a single haemodialysis session and is associated with time on dialysis. J Breath Res 2008; 2:026004. [DOI: 10.1088/1752-7155/2/2/026004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Carrero JJ, Stenvinkel P, Fellström B, Qureshi AR, Lamb K, Heimbürger O, Bárány P, Radhakrishnan K, Lindholm B, Soveri I, Nordfors L, Shiels PG. Telomere attrition is associated with inflammation, low fetuin-A levels and high mortality in prevalent haemodialysis patients. J Intern Med 2008; 263:302-12. [PMID: 18070000 DOI: 10.1111/j.1365-2796.2007.01890.x] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Chronic kidney disease (CKD) predisposes to a 10- to 20-fold increased cardiovascular risk. Patients undergo accelerated atherogenesis and vascular ageing. We investigated whether telomere attrition, a marker of cell senescence, contributes to this increased mortality risk. METHODS This is a cross-sectional study in prevalent haemodialysis patients [n = 175; 98 Males; median (range) age: 66 (23-86) years]. Biochemical markers of oxidative stress and inflammatory status were measured in relation to the patient's leucocyte telomere length. Overall mortality was assessed after a median of 31 (range 2-42) months. RESULTS Telomere length was shorter in CKD men, despite women being older (average +/- SD 6.41 +/- 1.23 vs. 6.96 +/- 1.48 kb, P = 0.002). Telomere length was associated with age (rho = -0.18, P = 0.01), fetuin-A (rho = 0.26, P = 0.0004), high-sensitivity C-reactive protein (rho = -0.21, P = 0.005) and IL-6 (rho = -0.17, P = 0.02). In a multivariate logistic regression (pseudo r(2) = 0.14), telomere length was associated with age >65 years (odds ratio: 2.11; 95% CI: 1.10, 4.06), sex (2.01; 1.05, 3.86), fetuin-A (1.85; 0.97, 3.50) and white blood cell count (2.04; 1.02, 4.09). Receiver operating characteristic curves identified a telomere length < 6.28 kb as a fair predictor of mortality. Finally, reduced telomere length was associated with increased mortality, independently of age, gender and inflammation (likelihood ratio 41.6, P < 0.0001), but dependently on fetuin-A levels. CONCLUSION Age and male gender seem to be important contributors to reduced telomere length in CKD patients, possibly via persistent inflammation. Reduced telomere length also contributes to the mortality risk of these patients through pathways that could involve circulating levels of fetuin-A.
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Affiliation(s)
- J J Carrero
- Divisions of Renal Medicine and Baxter Novum, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Karolinska University Hospital at Huddinge, Stockholm, Sweden
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16
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Chen D, Weber M, Shiels PG, Dong R, Webster Z, McVey JH, Kemball-Cook G, Tuddenham EGD, Lechler RI, Dorling A. Postinjury vascular intimal hyperplasia in mice is completely inhibited by CD34+ bone marrow-derived progenitor cells expressing membrane-tethered anticoagulant fusion proteins. J Thromb Haemost 2006; 4:2191-8. [PMID: 16803463 DOI: 10.1111/j.1538-7836.2006.02100.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Coagulation proteins promote neointimal hyperplasia and vascular remodelling after vessel injury, but the precise mechanisms by which they act in vivo remain undetermined. OBJECTIVES This study, using an injury model in which the neointima is derived from bone marrow (BM)-derived cells, compared inhibition of tissue factor or thrombin on either BM-derived or existing vascular smooth muscle cells. METHODS Two transgenic (Tg) mouse strains expressing membrane-tethered tissue factor pathway inhibitor (TFPI) or hirudin (Hir) fusion proteins driven by an alpha smooth muscle actin (SMA) promoter were generated (alpha-TFPI-Tg and alpha-Hir-Tg) and the phenotype after wire-induced endovascular injury was compared with that in wild-type (WT) controls. RESULTS WT mice developed progressive neointimal expansion, whereas injury in either Tg was followed by repair back to a preinjured state. This was also seen when WT mice were reconstituted with BM from Tg mice but not when Tgs were reconstituted with WT BM, in which injury was followed by slowly progressive neointimal expansion. Injection of CD34+ cells from Tg mice into injured WT mice resulted in the accumulation of fusion protein-expressing cells from day 3 onwards and an absence of neointimal hyperplasia in those areas. CONCLUSIONS Neointimal development after wire-induced endovascular injury in mice was completely inhibited when BM-derived cells infiltrating the damaged artery expressed membrane tethered anticoagulant fusion proteins under an alpha-SMA promoter. These findings enhance our understanding of the pathological role that coagulation proteins play in vascular inflammation.
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Affiliation(s)
- D Chen
- Department of Immunology, Imperial College London, Hammersmith Hospital, London, UK
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17
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Ashraf N, Zino S, MacIntyre A, Kingsmore D, Payne AP, George WD, Shiels PG. Altered sirtuin expression is associated with node-positive breast cancer. Br J Cancer 2006; 95:1056-61. [PMID: 17003781 PMCID: PMC2360714 DOI: 10.1038/sj.bjc.6603384] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Sirtuins are genes implicated in cellular and organismal ageing. Consequently, they are speculated to be involved in diseases of ageing including cancer. Various cancers with widely differing prognosis have been shown to have differing and characteristic expression of these genes; however, the relationship between sirtuin expression and cancer progression is unclear. In order to correlate cancer progression and sirtuin expression, we have assessed sirtuin expression as a function of primary cell ageing and compared sirtuin expression in normal, ‘nonmalignant’ breast biopsies to breast cancer biopsies using real-time polymerase chain reaction (PCR). Levels of SIRT7 expression were significantly increased in breast cancer (P<0.0001). Increased levels of SIRT3 and SIRT7 transcription were also associated with node-positive breast cancer (P<0.05 and P<0.0001, respectively). This study has demonstrated differential sirtuin expression between nonmalignant and malignant breast tissue, with consequent diagnostic and therapeutic implications.
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Affiliation(s)
- N Ashraf
- Division of Cancer Sciences and Molecular Pathology, Department of Surgery, University of Glasgow, Western Infirmary Glasgow, 44 Church Street, Glasgow G11 6NT, UK
| | - S Zino
- Division of Cancer Sciences and Molecular Pathology, Department of Surgery, University of Glasgow, Western Infirmary Glasgow, 44 Church Street, Glasgow G11 6NT, UK
| | - A MacIntyre
- Division of Cancer Sciences and Molecular Pathology, Department of Surgery, University of Glasgow, Western Infirmary Glasgow, 44 Church Street, Glasgow G11 6NT, UK
| | - D Kingsmore
- Renal Transplant Unit, Western Infirmary Glasgow, Glasgow, UK
| | - A P Payne
- IBLS, University of Glasgow, Glasgow, UK
| | - W D George
- Division of Cancer Sciences and Molecular Pathology, Department of Surgery, University of Glasgow, Western Infirmary Glasgow, 44 Church Street, Glasgow G11 6NT, UK
| | - P G Shiels
- Division of Cancer Sciences and Molecular Pathology, Department of Surgery, University of Glasgow, Western Infirmary Glasgow, 44 Church Street, Glasgow G11 6NT, UK
- E-mail:
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18
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Sklavounou E, Hay A, Ashraf N, Lamb K, Brown E, Mac Intyre A, George WD, Hartley RC, Shiels PG. The use of telomere biology to identify and develop superior nitrone based anti-oxidants. Biochem Biophys Res Commun 2006; 347:420-7. [PMID: 16828709 DOI: 10.1016/j.bbrc.2006.06.087] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Accepted: 06/15/2006] [Indexed: 11/28/2022]
Abstract
We have employed a biological chemistry approach to dissect the mechanisms underpinning cellular responses to oxidant stress and to develop biologically relevant anti-oxidants. We have used telomere biology to define cellular stress responses and have observed telomere independent, p21- and p16-dependent stasis following oxidative insult in human fibroblasts. This was accompanied by a [corrected] reduction in XRCC5 expression and a reduction in [corrected] SIRT 1 expression. Using these markers in conjunction with senescence-associated beta-galactosidase expression, we have developed and screened novel nitrone based anti-oxidant compounds. We have identified functional compounds that are unsuitable for use in primary human cells. This has allowed subsequent identification of suitably structured compounds that act as superior biological anti-oxidants, which have potential for use in clinical interventions.
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Affiliation(s)
- E Sklavounou
- Division of Cancer Sciences and Molecular Pathology University of Glasgow, Glasgow G12 8QQ, UK
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19
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Al-Fayez M, Russell D, Wayne Davies R, Shiels PG, Baker PJ, Payne AP. Deficits in the mid-brain raphe nuclei and striatum of the AS/AGU rat, a protein kinase C-γ mutant. Eur J Neurosci 2005; 22:2792-8. [PMID: 16324113 DOI: 10.1111/j.1460-9568.2005.04502.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The AS/AGU rat carries a recessive mutation (agu) in the gene coding for the gamma isoform of protein kinase C. The rat is characterized by disordered locomotion and progressive dysfunction of the nigrostriatal dopaminergic (DA) system. This dysfunction begins with a failure to release DA within the striatum and culminates in cell loss within the substantia nigra pars compacta. The present study examines another midbrain aminergic system with input to the basal ganglia, the serotonergic (5-HT) raphe-striatal system originating in the dorsal raphe nucleus. By 3 months after birth, there is a very substantial reduction in the extracellular levels of 5-HT in the dorsal caudate-putamen of the mutants compared with controls (c. 70%). This is accompanied by a proportional increase in the levels of the 5-HT metabolite 5-hydroxyindole acetic acid (5-HIAA). At a later age, there are reductions in whole tissue 5-HT (and increases in 5-HIAA) in both the striatum and the region containing the dorsal raphe nucleus, as well as numbers of 5-HT-immunoreactive cells in the dorsal raphe nucleus. The median raphe appears to be unaffected. The results are seen in terms of an initial dysfunction in transmitter release leading to cell death, perhaps through the formation of free radicals or neurotoxins.
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Affiliation(s)
- M Al-Fayez
- Department of Anatomy, King Saud University, Kingdom of Saudi Arabia
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Affiliation(s)
- P G Shiels
- Division of Cancer Sciences and Molecular Pathology, University of Glasgow, Glasgow, United Kingdom.
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Affiliation(s)
- A S Huett
- PPL Therapeutics Ltd, Roslin, Edinburgh, UK
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24
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Zomerdijk JC, Kieft R, Shiels PG, Borst P. Alpha-amanitin-resistant transcription units in trypanosomes: a comparison of promoter sequences for a VSG gene expression site and for the ribosomal RNA genes. Nucleic Acids Res 1991; 19:5153-8. [PMID: 1923801 PMCID: PMC328869 DOI: 10.1093/nar/19.19.5153] [Citation(s) in RCA: 92] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Transcription of the predominant surface antigen genes in Trypanosoma brucei is unusual in its resistance to the RNA polymerase inhibitor alpha-amanitin, a property typical for rDNA transcription in eukaryotes. Transcription of most other protein-coding genes in trypanosomes is sensitive to alpha-amanitin. To investigate whether RNA polymerase I, the polymerase that transcribes rRNA genes, can give rise to functional mRNAs in trypanosomes, we have fused the putative promoter of the T.brucei rRNA genes to the chloramphenicol acetyl transferase (CAT) gene and determined CAT activity after transient expression of chimeric constructs in procyclic trypanosomes. We show here that the rRNA promoter yields the same high CAT activity as the promoters for the two predominant surface antigen genes of trypanosomes, the Variant-specific Surface Glycoprotein (VSG) gene of bloodstream trypanosomes and the procyclin gene of insect-form trypanosomes, both of which are also transcribed by an alpha-amanitin-insensitive RNA polymerase. RNA polymerase I of trypanosomes seems therefore able to synthesize pre-mRNAs that are effectively processed into translatable mRNAs. Dissection of the promoter segments showed the minimal elements for a VSG gene expression site promoter to be confined to a segment of -60 to +77 bp, overlapping the most 5' putative transcription start sites as determined in vivo by RNase protection experiments. For the ribosomal promoter region a segment of -258 to +200 bp relative to the putative transcription start site was sufficient for maximal CAT activity. There is a precise requirement for specific nucleotides at the rRNA transcription start site. We detect no homology between the sequences required for promoter function of the three alpha-amanitin-resistant transcription units, rRNA, VSG and procyclin (parp) genes. This suggests that the sequence-specific recognition of these promoters either occurs by common factors detecting sequence homologies that escape us, or by separate factors that bind to different DNA sequences but interact with a common alpha-amanitin-resistant RNA polymerase.
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Affiliation(s)
- J C Zomerdijk
- Division of Molecular Biology, The Netherlands Cancer Institute, Amsterdam
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Zomerdijk JC, Kieft R, Duyndam M, Shiels PG, Borst P. Antigenic variation in Trypanosoma brucei: a telomeric expression site for variant-specific surface glycoprotein genes with novel features. Nucleic Acids Res 1991; 19:1359-68. [PMID: 1709274 PMCID: PMC333887 DOI: 10.1093/nar/19.7.1359] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
African trypanosomes evade the immune response of their host by periodically changing their variant surface glycoprotein (VSG) coat. Each coat is encoded by a separate VSG gene. Expressed genes are in a telomeric expression site (ES) and there are several sites in each trypanosome. To study the transcription control of VSG genes in Trypanosoma brucei we have analyzed an ES, called the dominant ES (DES), that readily switches off and on. The promoter area of the DES is very similar to that of the 221 ES (Zomerdijk et al., 1990). It can be switched off and on in vivo without detectable DNA alterations in the vicinity of the transcription start and it can drive high transient expression of a reporter gene in transfection experiments. However, there are also two major differences between the DES and the 221 ES. First, one version of the DES contains an additional upstream transcription unit overlapping the VSG gene ES promoter. The presence of this upstram transcription is dispensable, however, for the VSG gene ES promoter is active, even if transcription through this start from the upstream promoter is blocked using UV light. Moreover, a second version of the DES present in another trypanosome variant does not produce these upstream transcripts. Secondly, we find that the inactivation of DES transcription in one trypanosome variant is accompanied by DNA alterations in the DES upstream (greater than 2 kb) of the transcription start; reactivation of DES transcription is accompanied by another alteration far upstream. Although we cannot exclude that these DNA rearrangements are incidental, our results raise the possibility that the activity of ES promoters is negatively controlled in cis by far upstream sequences not included in transfection constructs and that alterations in these sequences may lead to (in)activation of the promoter.
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Affiliation(s)
- J C Zomerdijk
- Division of Molecular Biology, The Netherlands Cancer Institute, Amsterdam
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Matthews KR, Shiels PG, Graham SV, Cowan C, Barry JD. Duplicative activation mechanisms of two trypanosome telomeric VSG genes with structurally simple 5' flanks. Nucleic Acids Res 1990; 18:7219-27. [PMID: 2175429 PMCID: PMC332856 DOI: 10.1093/nar/18.24.7219] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In the mammalian bloodstream, African trypanosomes express variant surface glycoprotein (VSG) genes from a family of long and complex telomeric expression sites. VSG switching generally occurs by the duplication of different VSG genes into these sites by gene conversion involving a series of 70 base pair (70bp) repeats in the 5' flank. In contrast, when VSG is first synthesised by trypanosomes in the tsetse fly at the metacyclic stage, a separate set of telomeric expression sites is activated. These latter telomeres appear not to act as recipients in gene conversion. We have found that the structure of two such expression sites is simple, with very short 70bp repeat regions and very little other sequence in common with bloodstream expression sites. However, the two telomeres readily act as donors in VSG gene conversion in the bloodstream and we show for one a consistent association of the conversion 5' end point with the short 70bp repeat region. These findings help explain why a very predictable set of VSGs is expressed in the tsetse fly and have implications for VSG gene conversion mechanisms.
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Abstract
The metacyclic form of African trypanosomes is the first to express genes for the Variant Surface Glycoprotein (VSG) and it uses an unusually predictable subset of the VSG gene repertoire. We have developed a model system for the analysis of metacyclic VSG (M-VSG) gene expression and have used this to demonstrate that, for two M-VSG genes, different modes of expression operate in the insect and mammalian phases of the life-cycle. In metacyclic-derived clones, these genes are expressed in situ, whereas they are routinely activated by duplication in bloodstream trypanosomes. The expression loci for both M-VSG genes studied are structurally simple and we present a model, based on this, for the maintenance of a separate M-VSG repertoire and expression system.
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Affiliation(s)
- S V Graham
- Institute of Genetics, University of Glasgow, UK
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Barry JD, Graham SV, Matthews KR, Shiels PG, Shonekan OA. Stage-specific mechanisms for activation and expression of variant surface glycoprotein genes in Trypanosoma brucei. Biochem Soc Trans 1990; 18:708-10. [PMID: 2083654 DOI: 10.1042/bst0180708] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- J D Barry
- Wellcome Unit of Molecular Parasitology, University of Glasgow, U.K
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