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Fraszczyk E, Thio CHL, Wackers P, Dollé MET, Bloks VW, Hodemaekers H, Picavet HS, Stynenbosch M, Verschuren WMM, Snieder H, Spijkerman AMW, Luijten M. DNA methylation trajectories and accelerated epigenetic aging in incident type 2 diabetes. GeroScience 2022; 44:2671-2684. [PMID: 35947335 PMCID: PMC9768051 DOI: 10.1007/s11357-022-00626-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [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: 11/18/2021] [Accepted: 07/19/2022] [Indexed: 01/07/2023] Open
Abstract
DNA methylation (DNAm) patterns across the genome changes during aging and development of complex diseases including type 2 diabetes (T2D). Our study aimed to estimate DNAm trajectories of CpG sites associated with T2D, epigenetic age (DNAmAge), and age acceleration based on four epigenetic clocks (GrimAge, Hannum, Horvath, phenoAge) in the period 10 years prior to and up to T2D onset. In this nested case-control study within Doetinchem Cohort Study, we included 132 incident T2D cases and 132 age- and sex-matched controls. DNAm was measured in blood using the Illumina Infinium Methylation EPIC array. From 107 CpG sites associated with T2D, 10 CpG sites (9%) showed different slopes of DNAm trajectories over time (p < 0.05) and an additional 8 CpG sites (8%) showed significant differences in DNAm levels (at least 1%, p-value per time point < 0.05) at all three time points with nearly parallel trajectories between incident T2D cases and controls. In controls, age acceleration levels were negative (slower epigenetic aging), while in incident T2D cases, levels were positive, suggesting accelerated aging in the case group. We showed that DNAm levels at specific CpG sites, up to 10 years before T2D onset, are different between incident T2D cases and healthy controls and distinct patterns of clinical traits over time may have an impact on those DNAm profiles. Up to 10 years before T2D diagnosis, cases manifested accelerated epigenetic aging. Markers of biological aging including age acceleration estimates based on Horvath need further investigation to assess their utility for predicting age-related diseases including T2D.
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Affiliation(s)
- Eliza Fraszczyk
- Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Chris H L Thio
- Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Paul Wackers
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Martijn E T Dollé
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Vincent W Bloks
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Hennie Hodemaekers
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - H Susan Picavet
- Centre for Nutrition, Prevention and Health Services, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Marjolein Stynenbosch
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - W M Monique Verschuren
- Centre for Nutrition, Prevention and Health Services, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Harold Snieder
- Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Annemieke M W Spijkerman
- Centre for Nutrition, Prevention and Health Services, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Mirjam Luijten
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
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Pennings JLA, Abachin E, Esson R, Hodemaekers H, Francotte A, Claude JB, Vanhee C, Uhlrich S, Vandebriel RJ. Regulation of Clostridium tetani Neurotoxin Expression by Culture Conditions. Toxins (Basel) 2022; 14:toxins14010031. [PMID: 35051008 PMCID: PMC8778922 DOI: 10.3390/toxins14010031] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/22/2021] [Accepted: 12/29/2021] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Ensuring consistency of tetanus neurotoxin (TeNT) production by Clostridium tetani could help to ensure consistent product quality in tetanus vaccine manufacturing, ultimately contributing to reduced animal testing. The aim of this study was to identify RNA signatures related to consistent TeNT production using standard and non-standard culture conditions. METHODS We applied RNA sequencing (RNA-Seq) to study C. tetani gene expression in small-scale batches under several culture conditions. RESULTS We identified 1381 time-dependent differentially expressed genes (DEGs) reflecting, among others, changes in growth rate and metabolism. Comparing non-standard versus standard culture conditions identified 82 condition-dependent DEGs, most of which were specific for one condition. The tetanus neurotoxin gene (tetX) was highly expressed but showed expression changes over time and between culture conditions. The tetX gene showed significant down-regulation at higher pH levels (pH 7.8), which was confirmed by the quantification data obtained with the recently validated targeted LC-MS/MS approach. CONCLUSIONS Non-standard culture conditions lead to different gene expression responses. The tetX gene appears to be the best transcriptional biomarker for monitoring TeNT production as part of batch-to-batch consistency testing during tetanus vaccine manufacturing.
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Affiliation(s)
- Jeroen L. A. Pennings
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), 3721 MA Bilthoven, The Netherlands; (H.H.); (R.J.V.)
- Correspondence:
| | - Eric Abachin
- Sanofi Pasteur, 1541 Avenue Marcel Mérieux, 69280 Marcy l’Etoile, France; (E.A.); (R.E.); (S.U.)
| | - Raphaël Esson
- Sanofi Pasteur, 1541 Avenue Marcel Mérieux, 69280 Marcy l’Etoile, France; (E.A.); (R.E.); (S.U.)
| | - Hennie Hodemaekers
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), 3721 MA Bilthoven, The Netherlands; (H.H.); (R.J.V.)
| | - Antoine Francotte
- Department of Chemical and Physical Health Risks, Sciensano, 14 Rue Juliette Wytsman, 1050 Brussels, Belgium; (A.F.); (C.V.)
| | | | - Céline Vanhee
- Department of Chemical and Physical Health Risks, Sciensano, 14 Rue Juliette Wytsman, 1050 Brussels, Belgium; (A.F.); (C.V.)
| | - Sylvie Uhlrich
- Sanofi Pasteur, 1541 Avenue Marcel Mérieux, 69280 Marcy l’Etoile, France; (E.A.); (R.E.); (S.U.)
| | - Rob J. Vandebriel
- Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), 3721 MA Bilthoven, The Netherlands; (H.H.); (R.J.V.)
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Husby A, Pasanen A, Waage J, Sevelsted A, Hodemaekers H, Janssen R, Karjalainen MK, Stokholm J, Chawes BL, Korppi M, Wennergren G, Heinzmann A, Bont L, Bisgaard H, Bønnelykke K. CDHR3 gene variation and childhood bronchiolitis. J Allergy Clin Immunol 2017; 140:1469-1471.e7. [PMID: 28782631 DOI: 10.1016/j.jaci.2017.06.044] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 06/12/2017] [Accepted: 06/26/2017] [Indexed: 01/10/2023]
Affiliation(s)
- Anders Husby
- COPSAC, Copenhagen Prospective Studies on Asthma in Childhood, Faculty of Health and Medical Sciences, University of Copenhagen & Danish Pediatric Asthma Center, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Anu Pasanen
- PEDEGO Research Center and Medical Research Center Oulu, University of Oulu, Oulu, Finland; Department of Children and Adolescents, Oulu University Hospital, Oulu, Finland
| | - Johannes Waage
- COPSAC, Copenhagen Prospective Studies on Asthma in Childhood, Faculty of Health and Medical Sciences, University of Copenhagen & Danish Pediatric Asthma Center, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Astrid Sevelsted
- COPSAC, Copenhagen Prospective Studies on Asthma in Childhood, Faculty of Health and Medical Sciences, University of Copenhagen & Danish Pediatric Asthma Center, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Hennie Hodemaekers
- Centre for Health Protection, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - Riny Janssen
- Centre for Health Protection, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - Minna K Karjalainen
- PEDEGO Research Center and Medical Research Center Oulu, University of Oulu, Oulu, Finland; Department of Children and Adolescents, Oulu University Hospital, Oulu, Finland
| | - Jakob Stokholm
- COPSAC, Copenhagen Prospective Studies on Asthma in Childhood, Faculty of Health and Medical Sciences, University of Copenhagen & Danish Pediatric Asthma Center, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Bo L Chawes
- COPSAC, Copenhagen Prospective Studies on Asthma in Childhood, Faculty of Health and Medical Sciences, University of Copenhagen & Danish Pediatric Asthma Center, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Matti Korppi
- Pediatric Research Center, Tampere University and Tampere University Hospital, Tampere, Finland
| | - Göran Wennergren
- Department of Pediatrics, University of Gothenburg, Queen Silvia Children's Hospital, Gothenburg, Sweden
| | - Andrea Heinzmann
- Center for Pediatrics, Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Louis Bont
- University Medical Center Utrecht, Utrecht, The Netherlands; Respiratory Syncytial Virus Network (ReSViNET), Utrecht, The Netherlands
| | - Hans Bisgaard
- COPSAC, Copenhagen Prospective Studies on Asthma in Childhood, Faculty of Health and Medical Sciences, University of Copenhagen & Danish Pediatric Asthma Center, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark.
| | - Klaus Bønnelykke
- COPSAC, Copenhagen Prospective Studies on Asthma in Childhood, Faculty of Health and Medical Sciences, University of Copenhagen & Danish Pediatric Asthma Center, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark
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Pasanen A, Karjalainen MK, Bont L, Piippo-Savolainen E, Ruotsalainen M, Goksör E, Kumawat K, Hodemaekers H, Nuolivirta K, Jartti T, Wennergren G, Hallman M, Rämet M, Korppi M. Genome-Wide Association Study of Polymorphisms Predisposing to Bronchiolitis. Sci Rep 2017; 7:41653. [PMID: 28139761 PMCID: PMC5282585 DOI: 10.1038/srep41653] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 12/20/2016] [Indexed: 11/10/2022] Open
Abstract
Bronchiolitis is a major cause of hospitalization among infants. Severe bronchiolitis is associated with later asthma, suggesting a common genetic predisposition. Genetic background of bronchiolitis is not well characterized. To identify polymorphisms associated with bronchiolitis, we conducted a genome-wide association study (GWAS) in which 5,300,000 single nucleotide polymorphisms (SNPs) were tested for association in a Finnish–Swedish population of 217 children hospitalized for bronchiolitis and 778 controls. The most promising SNPs (n = 77) were genotyped in a Dutch replication population of 416 cases and 432 controls. Finally, we used a set of 202 Finnish bronchiolitis cases to further investigate candidate SNPs. We did not detect genome-wide significant associations, but several suggestive association signals (p < 10−5) were observed in the GWAS. In the replication population, three SNPs were nominally associated (p < 0.05). Of them, rs269094 was an expression quantitative trait locus (eQTL) for KCND3, previously shown to be associated with occupational asthma. In the additional set of Finnish cases, the association for another SNP (rs9591920) within a noncoding RNA locus was further strengthened. Our results provide a first genome-wide examination of the genetics underlying bronchiolitis. These preliminary findings require further validation in a larger sample size.
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Affiliation(s)
- Anu Pasanen
- PEDEGO Research Unit, Medical Research Center Oulu, University of Oulu, and Department of Children and Adolescents, Oulu University Hospital, Oulu, Finland
| | - Minna K Karjalainen
- PEDEGO Research Unit, Medical Research Center Oulu, University of Oulu, and Department of Children and Adolescents, Oulu University Hospital, Oulu, Finland
| | - Louis Bont
- Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Marja Ruotsalainen
- Kuopio University Hospital, Pediatrics, University of Eastern Finland, Kuopio, Finland
| | - Emma Goksör
- Department of Pediatrics, University of Gothenburg, Queen Silvia Children's Hospital, Gothenburg, Sweden
| | - Kuldeep Kumawat
- Department of Immunology, Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Hennie Hodemaekers
- RIVM, National Institute for Public Health and the Environment, GZB, Center for Health Protection, Bilthoven, The Netherlands
| | - Kirsi Nuolivirta
- Department of Pediatrics, Seinäjoki Central Hospital, Seinäjoki, Finland
| | - Tuomas Jartti
- Department of Pediatrics, University of Turku and Turku University Hospital, Turku, Finland
| | - Göran Wennergren
- Department of Pediatrics, University of Gothenburg, Queen Silvia Children's Hospital, Gothenburg, Sweden
| | - Mikko Hallman
- PEDEGO Research Unit, Medical Research Center Oulu, University of Oulu, and Department of Children and Adolescents, Oulu University Hospital, Oulu, Finland
| | - Mika Rämet
- PEDEGO Research Unit, Medical Research Center Oulu, University of Oulu, and Department of Children and Adolescents, Oulu University Hospital, Oulu, Finland.,BioMediTech, University of Tampere, Tampere, Finland
| | - Matti Korppi
- Center for Child Health Research, Tampere University and Tampere University Hospital, Tampere, Finland
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van Esterik JC, Dollé ME, Imholz S, Hodemaekers H, van Leeuwen SP, Hamers T, Legler J, van der Ven LT. Perinatal programming of obesity later in life by the endocrine disruptor bisphenol A in a mouse model. Reprod Toxicol 2011. [DOI: 10.1016/j.reprotox.2011.06.024] [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: 11/28/2022]
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Schuurhof A, Bont L, Siezen CLE, Hodemaekers H, van Houwelingen HC, Kimman TG, Hoebee B, Kimpen JLL, Janssen R. Interleukin-9 polymorphism in infants with respiratory syncytial virus infection: an opposite effect in boys and girls. Pediatr Pulmonol 2010; 45:608-13. [PMID: 20503287 DOI: 10.1002/ppul.21229] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [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: 12/12/2022]
Abstract
The predominance of severe respiratory syncytial virus (RSV) bronchiolitis in boys compared to girls is well known, but its mechanism is not yet understood. This is the first study focusing on gender-specific genetic factors affecting the risk of severe RSV infection using a previously described cohort. We determined 347 single-nucleotide polymorphisms (SNPs) in 470 children hospitalized for RSV infection, their parents, and 1,008 random population controls. We tested if these SNPs exerted a different effect in boys and girls by performing statistical interaction tests. Only one SNP (rs2069885) had a gender-specific significant association with RSV infection, severe enough to require hospitalization (P-value 0.00057). The major allele of this structural polymorphism in the interleukin (IL)-9 gene is associated with an increased susceptibility to severe RSV infection in boys, while there is a decreased susceptibility in girls. Haplotype analysis of two SNPs in the IL-9 gene (rs2069885 and rs1799962) showed overrepresentation of the TT haplotype in girls with severe RSV bronchiolitis requiring hospitalization indicating that this is the haplotype conferring the highest risk in girls. In conclusion, the IL-9 genetic polymorphism (rs2069885) has an opposite effect on the risk of severe RSV bronchiolitis in boys and girls. Although so far a difference in IL-9 production in boys and girls has not been reported, this study may help in explaining the different risks of severe RSV bronchiolitis in boys and girls.
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Affiliation(s)
- Annemieke Schuurhof
- Laboratory for Health Protection Research, National Institute for Public Health and the Environment, Bilthoven, the Netherlands
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Janssen R, Pennings J, Hodemaekers H, Buisman A, van Oosten M, de Rond L, Oztürk K, Dormans J, Kimman T, Hoebee B. Host transcription profiles upon primary respiratory syncytial virus infection. J Virol 2007; 81:5958-67. [PMID: 17376894 PMCID: PMC1900269 DOI: 10.1128/jvi.02220-06] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [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: 12/26/2022] Open
Abstract
Respiratory syncytial virus (RSV) is a common cause of severe lower respiratory tract infection in children. Severe RSV disease is related to an inappropriate immune response to RSV resulting in enhanced lung pathology which is influenced by host genetic factors. To gain insight into the early pathways of the pathogenesis of and immune response to RSV infection, we determined the transcription profiles of lungs and lymph nodes on days 1 and 3 after infection of mice. Primary RSV infection resulted in a rapid but transient innate, proinflammatory response, as exemplified by the induction of a large number of type I interferon-regulated genes and chemokine genes, genes involved in inflammation, and genes involved in antigen processing. Interestingly, this response is much stronger on day 1 than on day 3 after infection, indicating that the strong transcriptional response in the lung precedes the peak of viral replication. Surprisingly, the set of down-regulated genes was small and none of these genes displayed strong down-regulation. Responses in the lung-draining lymph nodes were much less prominent than lung responses and are suggestive of NK cell activation. Our data indicate that at time points prior to the peak of viral replication and influx of inflammatory cells, the local lung response, measured at the transcriptional level, has already dampened down. The processes and pathways induced shortly after RSV infection can now be used for the selection of candidate genes for human genetic studies of children with severe RSV infection.
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Affiliation(s)
- Riny Janssen
- Laboratory for Toxicology, Pathology and Genetics, PB 12, National Institute for Public Health and the Environment, P.O. Box 1, 3720 BA Bilthoven, The Netherlands.
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de Stoppelaar JM, Faessen P, Zwart E, Hozeman L, Hodemaekers H, Mohn GR, Hoebee B. Isolation of DNA probes specific for rat chromosomal regions 19p, 19q and 4q and their application for the analysis of diethylstilbestrol-induced aneuploidy in binucleated rat fibroblasts. Mutagenesis 2000; 15:165-75. [PMID: 10719043 DOI: 10.1093/mutage/15.2.165] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [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: 11/14/2022] Open
Abstract
DNA probes specific for rat chromosomes 19p, 19q and 4q were isolated, characterized and used for the detection and analysis of diethylstilbestrol(DES)-induced aneuploidy. By denaturing and partially reassociating total genomic DNA a new rat repetitive DNA family was isolated, which was located on chromosome 19p21. Sequencing of a number of subclones from cos76-1 and other clones of this so-called 76-family revealed that the repeat units are interrupted with large areas of other (unique) DNA. Consequently, after fluorescence in situ hybridization (FISH) the signals in interphase nuclei are large and spread out. The other two probes, cos25 (chromosome 4q) and cos42-47 (chromosome 19q), were isolated by screening cosmid libraries with probes isolated previously in our laboratory. The repeat unit of cos25 is a 2174 bp long EcoRI unit that contains three Sau3A sites and is tandemly organized. Sequencing of subclones of cos42-47 revealed that this probe was in fact the 5S RNA gene, located on 19q12. In order to determine if these probes were suitable probes for aneuploidy detection, two series of dual colour FISH with the combinations cos25/cos76-1 (4q/19p) and cos42-47/cos76-1 (19q/19p) were carried out on slides from an in vitro micronucleus assay with DES. With all three probes used, an increase in binucleated cells with non-disjunction or chromosome loss was observed in the DES-treated cultures. Scoring of additional micronucleated cells on slides hybridized with the cos25/cos76-1 (4q/19p) probes revealed that the hybridization signal of probe cos25 (4q) was over-represented in the micronuclei of the control cultures. The simultaneous use of the 19q and 19p probes is a particularly valuable tool for the detection of aneuploidy, since it allows distinction between aneugenic and clastogenic events in binucleated cells. Results of this analysis showed that apart from aneuploidy, DES also induced structural chromosome aberrations, although to a lesser extent.
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Affiliation(s)
- J M de Stoppelaar
- Laboratory of Health Effects Research, National Institute of Public Health and Environment, PO Box 1, 3720 BA Bilthoven, The Netherlands
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Terleth C, van Laar T, Schouten R, van Steeg H, Hodemaekers H, Wormhoudt T, Cornelissen-Steijger PD, Abrahams PJ, van der Eb AJ. A lack of radiation-induced ornithine decarboxylase activity prevents enhanced reactivation of herpes simplex virus and is linked to non-cancer proneness in xeroderma pigmentosum patients. Cancer Res 1997; 57:4384-92. [PMID: 9331102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Patients with xeroderma pigmentosum (XP), a DNA repair disorder, run a large risk of developing skin cancer in sun-exposed areas. Cancer proneness in these patients correlates with a mammalian SOS-like response, "enhanced reactivation (ER) of viruses." Here, we report that radiation-induced activation of the ornithine decarboxylase (ODC) gene, a putative proto-oncogene, is required for this response. Various diploid fibroblast strains derived from a non-cancer-prone subclass of XP patients, which lack the ER response, were irradiated with 2 J/m2 and assessed for gene induction. In these fibroblasts, an absence of induction of ODC by UV-C was observed at the levels of mRNA, protein, and enzyme activity. This lack of induction is quite specific because the genes for fos and collagenase were induced as they were in normal XP cells. The apparent linkage between non-cancer proneness and a lack of ER and ODC induction was confirmed in a fibroblast strain derived from a patient with another DNA repair disorder, trichothiodystrophy, which does not lead to cancer proneness: in these cells, no induction of the ER response nor of ODC occurs after UV-C irradiation. Repair deficiency, however, is not essential because the simultaneous lack of ODC and ER induction after 10 J/m2 UV-C was found in at least one repair-proficient fibroblast. Next, a specific inhibitor of ODC, difluoromethylornithine, at a dose of 10 mM, completely blocked the ER response in cultured normal skin fibroblasts, suggesting that the ODC enzyme is in fact essential for the ER response. Difluoromethylornithine, although it did not affect other processes such as DNA repair, leads to a block in the cell division cycle at the G1-S transition. Interestingly, other blockers of this transition, wortmannin (500 nM) and mimosine (100 mM), also decreased the ER response. Finally, the ER and ODC responses also seem to be linked after treatment with X-irradiation (3 Gy), suggesting that both are part of a general response to DNA damage, at least in human skin fibroblasts. Apart from the abnormal ER and ODC responses, fibroblasts from non-tumor-prone XP patients react in the same way to radiation as do fibroblasts from tumor-prone XP patients with respect to other parameters. Thus, the lack of ODC induction after radiation may help to protect XP patients against skin carcinogenesis.
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Affiliation(s)
- C Terleth
- Laboratory for Molecular Carcinogenesis, Sylvius Laboratories, Leiden University, The Netherlands
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