Telomere-based proliferative lifespan barriers in Werner-syndrome fibroblasts involve both p53-dependent and p53-independent mechanisms

Davis, Terence; Singhrao, Simarjit Kaur; Wyllie, F. S.; Haughton, Michele Fleur; Smith, Paul J.; Wiltshire, Marie; Wynford-Thomas, David; Jones, Christopher J.; Faragher, R. G. A.; Kipling, David

doi:10.1242/jcs.00331

Cited by 52 publications

(46 citation statements)

References 42 publications

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“…Gene expression patterns in senescent WS cells overlap with those in normal strains (35), and senescence seems to be a p53-dependent event mediated via pathways identical to those in normal cells (36). We saw no induction of p53 in either old or WS cells ( Table 6), indicating that the gene profiles reflected early passage rather than cellular senescence.…”

Section: Discussionmentioning

confidence: 70%

Gene expression profiling in Werner syndrome closely resembles that of normal aging

Kyng

May

Kølvraa

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

135

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Werner syndrome (WS) is a premature aging disorder, displaying defects in DNA replication, recombination, repair, and transcription. It has been hypothesized that several WS phenotypes are secondary consequences of aberrant gene expression and that a transcription defect may be crucial to the development of the syndrome. We used cDNA microarrays to characterize the expression of 6,912 genes and ESTs across a panel of 15 primary human fibroblast cell lines derived from young donors, old donors, and WS patients. Of the analyzed genes, 6.3% displayed significant differences in expression when either WS or old donor cells were compared with young donor cells. This result demonstrates that the WS transcription defect is specific to certain genes. Transcription alterations in WS were strikingly similar to those in normal aging: 91% of annotated genes displayed similar expression changes in WS and in normal aging, 3% were unique to WS, and 6% were unique to normal aging. We propose that a defect in the transcription of the genes as identified in this study could produce many of the complex clinical features of WS. The remarkable similarity between WS and normal aging suggests that WS causes the acceleration of a normal aging mechanism. This finding supports the use of WS as an aging model and implies that the transcription alterations common to WS and normal aging represent general events in the aging process.W erner syndrome (WS) is an autosomal recessive disease characterized by early onset of many signs of normal aging, such as graying of the hair, scleroderma-like skin changes, ocular cataracts, diabetes, degenerative vascular disease, osteoporosis, and high incidence of some types of cancers (1). As a segmental progeroid syndrome, WS does not exhibit all of the features of normal aging but nevertheless is a very useful model system for the molecular study of normal aging.The molecular basis of WS is a single mutation in the WRN gene, resulting in a truncated WS protein (WRN) characterized by a loss of nuclear localization signal and protein function (2). WRN has been demonstrated to possess helicase and exonuclease activities (3, 4) and belongs to the RecQ family of helicases. Various defects in DNA replication, recombination, repair, and transcription are found in WS fibroblasts (reviewed in ref. 5). The mechanisms by which the biochemical deficiencies resulting from WRN mutations lead to the characteristic pathology of the syndrome are not yet understood. It has been hypothesized that several WS phenotypes are secondary consequences of aberrant gene expression (6) and that a transcription defect may be crucial to the development of the syndrome (7). Increasing evidence suggests that WRN has a role in transcription. Human WRN activates transcription in a yeast system (8), and recent studies from this laboratory demonstrated that RNA polymerase (pol) II transcription is reduced by 40-60% in WS cells, indicating a primary defect in transcription (7). Supporting this finding, we found that RNA pol II transcription i...

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Section: Discussionmentioning

confidence: 70%

Gene expression profiling in Werner syndrome closely resembles that of normal aging

Kyng

May

Kølvraa

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

135

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“…HCA2 cells that have been immortalised by the ectopic expression of human telomerase (herein called HCA2.trt cells) have been described previously ). All cells were grown in Dulbecco's modified Eagle medium (DMEM) supplemented with 10% foetal calf serum in an atmosphere containing 5% CO 2 , and passaged every 4-5 days as described previously (Davis et al 2003). PDs were calculated according to the formula: PDs = log 2 (N t /N o ), where N t is number of cells counted and N o is number of cells seeded.…”

Section: Cells and Cell Culturementioning

confidence: 99%

“…Protein samples were prepared in lysis buffer containing the phosphatase inhibitors NaF and Na 3 VO 4 , separated on 12% sodium-dodecylsulphate/ polyacrylamide electrophoresis gels, electroblotted to immobilon-P polyvinylidene difluoride or nitrocellulose membranes (Millipore, Watford, UK) and antibodies applied as described previously (Davis et al 2003). The antibodies used were: mouse monoclonal anti-HSP27 (G31), rabbit polyclonal anti-phospho-(S82)-HSP27, anti-p38, anti-phospho(T180/Y182)-p38, rabbit monoclonal anti-JNK1/2 (56G8), anti-phospho-(T183/Y185)-JNK1/2, rabbit monoclonal anti-c-Jun (60A8) (Cell Signalling, New England Biolabs, Hitchin, UK).…”

Section: Immunoblot Analysismentioning

confidence: 99%

Assessing the role of stress signalling via p38 MAP kinase in the premature senescence of Ataxia Telangiectasia and Werner syndrome fibroblasts

Davis

Kipling

2008

Biogerontology

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The premature ageing Ataxia Telangiectasia (AT) and Werner syndromes (WS) are associated with accelerated cellular ageing. Young WS fibroblasts have an aged appearance and activated p38 MAP kinase, and treatment with the p38 inhibitor SB230580 extends their lifespan to within the normal range. SB203580 also extends the replicative lifespan of normal adult dermal fibroblasts, however, the effect is much reduced when compared to WS cells, suggesting that WS fibroblasts undergo a form of stress-induced premature senescence (SIPS). A small lifespan extension is seen in AT cells, which is not significant compared to normal fibroblasts, and the majority of young AT cells do not have an aged appearance and lack p38 activation, suggesting that the premature ageing does not result from SIPS. The lack of p38 activation is supported by the clinical manifestation, since AT is not associated with inflammatory disease, whereas WS individuals are predisposed to atherosclerosis, type II diabetes and osteoporosis, conditions known to be associated with p38 activation.

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“…Thus, it is possible that the common stress response could involve more genes than the 85 identified here. Gene expression patterns in senescent WS cells overlap with those in normal strains (Choi et al, 2001), and senescence appears to be a p53-dependent event mediated via pathways identical to those in normal cells (Davis et al, 2003). We saw no significant induction of p53 in neither old nor WS cells (see Supplementary Table 6), indicating that the gene profiles reflected early passage rather than cellular senescence.…”

Section: Discussionmentioning

confidence: 73%

Gene expression responses to DNA damage are altered in human aging and in Werner Syndrome

et al. 2005

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The accumulation of DNA damage and mutations is considered a major cause of cancer and aging. While it is known that DNA damage can affect changes in gene expression, transcriptional regulation after DNA damage is poorly understood. We characterized the expression of 6912 genes in human primary fibroblasts after exposure to three different kinds of cellular stress that introduces DNA damage: 4-nitroquinoline-1-oxide (4NQO), c-irradiation, or UV-irradiation. Each type of stress elicited damage specific gene expression changes of up to 10-fold. A total of 85 genes had similar changes in expression of 3-40-fold after all three kinds of stress. We examined transcription in cells from young and old individuals and from patients with Werner syndrome (WS), a segmental progeroid condition with a high incidence of cancer, and found various age-associated transcriptional changes depending upon the type of cellular stress. Compared to young individuals, both WS and old individuals had similarly aberrant transcriptional responses to c-and UV-irradiation, suggesting a role for Werner protein in stress-induced gene expression. Our results suggest that aberrant DNA damage-induced gene regulation may contribute to the aging process and the premature aging in WS.

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Telomere-based proliferative lifespan barriers in Werner-syndrome fibroblasts involve both p53-dependent and p53-independent mechanisms

Cited by 52 publications

References 42 publications

Gene expression profiling in Werner syndrome closely resembles that of normal aging

Gene expression profiling in Werner syndrome closely resembles that of normal aging

Assessing the role of stress signalling via p38 MAP kinase in the premature senescence of Ataxia Telangiectasia and Werner syndrome fibroblasts

Gene expression responses to DNA damage are altered in human aging and in Werner Syndrome

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