Hoarse voice resulting from premature ageing in Werner's syndrome

Werner's syndrome is characterized by clinical signs of premature ageing. A 42-year-old man presented with three-year history of hoarseness. Also noted were skin atrophy of the face and hands, ulcerations around the ankles, and a history of cataracts. A clinical diagnosis of Werner's syndrome was made. Laryngoscopy revealed bowed vocal folds resulting in a spindle-shaped defect with glottal incompetence during phonation. Examination also revealed decreased maximum phonation time and vocal fatigue. At surgery, atrophy of the vocalis muscle was noted. Furthermore, degeneration of muscle fibres was noted in the temporalis muscle. The atrophic changes in the vocal folds that occur with ageing and result in an increased fundamental frequency were seen in this patient. The characteristic hoarseness of Werner's syndrome appears to be the result of premature ageing of the vocal-folds.

Lack of effect of caffeine post-treatment on X-ray-induced chromosomal aberrations in Werner's syndrome lymphoblastoid cell lines: a preliminary report

PURPOSE

To investigate whether in Werner's syndrome cells the G2 phase of the cell cycle has some abnormal response to post-treatment with agents such as caffeine and hydroxyurea known to interfere with cellular response to DNA damage.

MATERIALS AND METHODS

Two Werner's syndrome lymphoblastoid cell lines (KO375 and DJG) and the normal cell line SNW646 were exposed to 50 cGy of X-rays or mitomycin-C and posttreated with caffeine or hydroxyurea in the G2 phase of the cell cycle.

RESULTS

Hydroxyurea post-treatment potentiated the X-ray-induced aberration levels both in the normal and Werner's syndrome (KO375 and DJG) cell lines; in contrast caffeine was only effective in the normal cell line. Similar results were observed when Werner's syndrome cells were treated in the G1 phase with the S-dependent agent mitomycin-C and post-treated with caffeine in G2, extending the observation that Werner's syndrome cells are unaffected by caffeine G2 post-treatment.

CONCLUSIONS

These results show a lack of caffeine effect in Werner's syndrome cells, suggesting an involvement of the Werner's syndrome protein in the signal transduction pathway by which caffeine could override the DNA damage induced G2 checkpoint.

The Werner syndrome protein is involved in RNA polymerase II transcription

Werner syndrome (WS) is a human progeroid syndrome characterized by the early onset of a large number of clinical features associated with the normal aging process. The complex molecular and cellular phenotypes of WS involve characteristic features of genomic instability and accelerated replicative senescence. The gene involved (WRN) was recently cloned, and its gene product (WRNp) was biochemically characterized as a helicase. Helicases play important roles in a variety of DNA transactions, including DNA replication, transcription, repair, and recombination. We have assessed the role of the WRN gene in transcription by analyzing the efficiency of basal transcription in WS lymphoblastoid cell lines that carry homozygous WRN mutations. Transcription was measured in permeabilized cells by [3H]UTP incorporation and in vitro by using a plasmid template containing the RNA polymerase II (RNA pol II)-dependent adenovirus major late promoter. With both of these approaches, we find that the transcription efficiency in different WS cell lines is reduced to 40-60% of the transcription in cells from normal individuals. This defect can be complemented by the addition of normal cell extracts to the chromatin of WS cells. Addition of purified wild-type WRNp but not mutated WRNp to the in vitro transcription assay markedly stimulates RNA pol II-dependent transcription carried out by nuclear extracts. A nonhelicase domain (a direct repeat of 27 amino acids) also appears to have a role in transcription enhancement, as revealed by a yeast hybrid-protein reporter assay. This is further supported by the lack of stimulation of transcription when mutant WRNp lacking this domain was added to the in vitro assay. We have thus used several approaches to show a role for WRNp in RNA pol II transcription, possibly as a transcriptional activator. A deficit in either global or regional transcription in WS cells may be a primary molecular defect responsible for the WS clinical phenotype.

p53-mediated apoptosis is attenuated in Werner syndrome cells

The WRN DNA helicase is a member of the DExH-containing DNA helicase superfamily that includes XPB, XPD, and BLM. Mutations in WRN are found in patients with the premature aging and cancer susceptibility syndrome known as Werner syndrome (WS). p53 binds to the WRN protein in vivo and in vitro through its carboxyl terminus. WS fibroblasts have an attenuated p53- mediated apoptotic response, and this deficiency can be rescued by expression of wild-type WRN. These data support the hypothesis that p53 can induce apoptosis through the modulation of specific DExH-containing DNA helicases and may have implications for the cancer predisposition observed in WS patients.

Differential regulation of PAI-1 gene expression in human fibroblasts predisposed to a fibrotic phenotype

Synthesis of the major negative physiologic regulator of plasmin activation [plasminogen activator inhibitor type-1 (PAI-1)] is elevated during progressive cellular senescence, in premature aging disorders (e.g., Werner's syndrome), and in conditions associated with tissue fibrosis and excessive fibrin accumulation (e.g., sclerosis, keloid formation). Dermal fibroblasts derived from Werner's patients as well as from keloid lesions markedly overexpress PAI-1 mRNA transcripts compared to normal skin fibroblasts. Such cell type-related differences in steady-state PAI-1 mRNA content, and variances in the relative abundance of the 3.0- compared to the 2.2-kb PAI-1 mRNA species, served to discriminate normal from Werner's and keloid fibroblasts. This disparity in PAI-1 mRNA levels paralleled transcriptional activities of the PAI-1 gene; de novo synthesis of PAI-1 protein among the three cell types, moreover, closely approximated the respective differences in total PAI-1 mRNA content. Despite the markedly elevated levels of PAI-1 mRNA and protein evident in newly confluent keloid fibroblasts, these cells effectively suppressed PAI-1 synthesis (as did normal dermal fibroblasts) upon culture in serum-free medium. Werner's syndrome skin fibroblasts, in contrast, continued to maintain high-level PAI-1 expression even after 3 days of growth arrest. Adhesion-mediated attenuation of serum-stimulated PAI-1 expression, a characteristic of normal cells involving sequences which mapped to the distal 5' flanking region of the PAI-1 gene, was retained in keloid but not Werner's fibroblasts. Collectively, these data suggest that (1) specific controls on PAI-1 gene expression are fundamentally different between these two clinically significant high PAI-1-synthesizing cell types and (2) the localized keloid may define the emergence of a distinct profibrotic dermal fibroblastoid phenotype in genetically predisposed individuals.

Werner syndrome lymphoblastoid cells are sensitive to camptothecin-induced apoptosis in S-phase

Werner Syndrome (WRN) is an autosomal recessive disorder showing an endogenous mutator phenotype in combination with an elevated risk of predominantly mesenchymal cancer. The gene mutated in WRN patients codes for 3'-->5' DNA helicase and 3'-->5' exonuclease activities. We have found similar S-phase arrest in both WRN and control cells after treatment with the DNA-topoisomerase-I-trapping drug camptothecin; this may be responsible for the drug-exposure-related growth inhibition seen in both cell types. A clearer phenotypic difference between WRN and control immortalized B-cell lines (LCLs) is obtained by examining cell death. The mechanism of camptothecin-induced cell death in WRN-deficient LCLs appears to be through apoptosis, a phenotype that strongly differentiates WRN-deficient from wild-type LCLs. We hypothesize that, in cells deficient for WRN function, a topoisomerase-I-DNA intermediate persists. Conflict with DNA replication may lead to apoptosis, increased mutation rates, and cancer in WRN.

Failure to complement abnormal phenotypes of simian virus 40-transformed Werner syndrome cells by introduction of a normal human chromosome 8

The Werner syndrome (WS) gene (WRN) was isolated by positional cloning, based on mapping to chromosome 8p12, and the WRN protein was recently shown to encode an active helicase. To examine functional complementation of WS phenotypes by expression of the WRN gene, we introduced a normal human chromosome 8 into a SV40-transformed WS fibroblastoid cell line (WS780) by microcell fusion and studied several cellular phenotypes associated previously with WS cell lines, including cell growth rate, 4-nitroquinoline-1-oxide (4NQO) sensitivity, and spontaneous mutation rate and type of mutation at the hypoxanthine-guanine phosphoribosyl transferase locus. The WRN gene was expressed in two of three microcell hybrids introduced with chromosome 8. We failed to observe a difference between normal and WS cell lines in terms of growth rates and spontaneous mutation rates. However, we found that the WS cell line was highly sensitive to 4NQO-induced cytotoxicity and showed an unusually high proportion of deletion mutations at the hypoxanthine-guanine phosphoribosyl transferase locus as compared to a control cell line, as shown previously. Here, we report that these phenotypes were not corrected by introduction of the WRN gene, although the WRN protein was expressed. Our results suggest that the hypersensitivity to 4NQO and the extensive deletion mutations observed in the WS cell line are caused by a defect that is secondary to the WRN gene mutation, possibly a repair gene defect that controls the phenotypes of hypersensitivity to carcinogen(s) and/or the extensive deletion mutations.

Aging-associated neuropathology in Werner syndrome

Werner syndrome (WS) is an autosomal recessive disorder associated with evidence of accelerated systemic aging, but generally thought not to involve the central nervous system. We examined two WS cases utilizing a sensitive Bielschowsky silver stain and immunohistochemistry for amyloid beta peptide (A beta) and hyperphosphorylated tau. Extensive frontal and temporal lobe A beta deposition was observed in the oldest (age 57 years) WS case and restricted neurofibrillary pathology was seen in the medial temporal lobe of both cases. The severity of A beta deposition in the medial temporal lobe of the oldest case exceeded that observed in our control cases and that reported in the literature. Our findings suggest that the apparent accelerated aging observed in WS can involve the central nervous system and may implicate the recently observed WRN locus mutation associated with WS in the neuropathology of aging and aging-associated diseases.

Lateral supramalleolar flap for heel coverage in a patient with Werner's syndrome

The repair of intractable ulcer over the Achilles' tendon in a patient with Werner's syndrome is described. The ulcer was covered successfully with a lateral supramalleolar flap combined with a delay procedure. Partial necrosis of the flap occurred; however, the necrotic area could be repaired with a skin graft because the underlying adipofascia of the flap survived. Histopathological studies revealed marked dermal fibrosis spreading to the subcutis, however the deep adipofascia was not so afflicted. The lateral supramalleolar flap, if combined with a delay procedure, can be used as a first choice in the repair of an ulcer in the heel region as long as apparent arteriosclerotic changes do not exist.

Effect of age and apoptosis on the mouse homologue of the huWRN gene

Werner's syndrome (WS) is an inherited disease with clinical symptoms which resemble premature aging. The Werner's syndrome gene (WRN), which is located on human chromosome 8p12, encodes a predicted protein of 1432 amino acids and shows significant similarity to DNA helicases. We have cloned the full-length mouse cDNA homologue of the human WRN gene encoding a predicted protein of 1320 amino acids and have obtained a full-length 70 kb genomic clone containing the moWRN gene. This gene has been mapped to chromosome 8A3 in mice. The expression of the moWRN gene was increased during apoptosis after IL-2 deprivation, and decreased in the spleen of aged mice. Lymphoid cells isolated from a patient with WS exhibited increased apoptosis after incubation with anti-Fas but not after incubation with the topoisomerase inhibitor VP16. RNase protection reviled dysregulation of the ICE family of apoptosis molecules in the WS cell line. These results indicate that the WS helicase is involved in certain pathways of apoptosis, and defective WS gene expression leads to accumulation of cells that are highly susceptibility to Fas-induced apoptosis.

Differential effects of cytotoxic drugs on mortal and immortalized B-lymphoblastoid cell lines from normal and Werner's syndrome patients

We studied the effects of nine cytotoxic drugs on three groups of B-lymphoblastoid cell lines transformed by Epstein-Barr virus (EBV): group 1, mortal cell lines from normal individuals; group 2, immortalized cell lines from normal individuals with strong telomerase activity; group 3, mortal cell lines from Werner's syndrome (WS) patients. Aminoglycoside antibiotics and alkylating drugs showed significantly stronger cytotoxic effects on immortalized cell lines than on mortal cell lines or the cell lines before immortalization. In contrast, topoisomerase II inhibitors showed no difference or they tended to be less cytotoxic to immortalized cell lines. Mortal cell lines from normal individuals and WS patients showed no difference in sensitivity against all the drugs examined except for the topoisomerase I inhibitor, camptothecin, which had a stronger cytotoxic effect on WS cell lines than other cell lines. We discuss the mechanisms underlying these cytotoxic effects.

[Werner's syndrome]

BACKGROUND

Werner's syndrome associates early aging in young adults, small height, cataract, glucose intolerance, hypogonadism, skin ulcers, vascular calcifications and osteoporosis.

CASE REPORT

We report a new case of Werner's syndrome in a 34-year-old man with suggestive alterations of the skin and endocrine anomalies in addition to hypospadias, urethral stenosis, bilateral mega-ureter and chronic renal failure.

DISCUSSION

The diagnosis of Werner's syndrome in our patient was unquestionable because of the clinical presentation and the familial context. However, the urology anomalies have not been reported in this syndrome. A simple coincidence cannot be excluded.

Hierarchical deterioration of body systems in Werner's syndrome: implications for normal ageing

Normal human ageing is a complicated biological phenomenon. 'Werner's syndrome (WS)', caused by mutations of RecQ type DNA helicase, has been recognized as a top ranking 'segmental' progeroid syndrome. Patients with WS show a wide variety of clinical and biological manifestations in the four major self-assembly body systems (nervous, immune, connective tissue and endocrine-metabolic systems) similar to normal ageing at an early stage of their life, followed by death at an average age of 46. The sequential appearance of clinical and biological deterioration of the body systems observed in WS suggested that the disorder is more than a segmental progeroid syndrome, analysis of which may shed new light on the question 'Why and how we age?'

Abnormal telomere dynamics of B-lymphoblastoid cell strains from Werner's syndrome patients transformed by Epstein-Barr virus

The characteristics of B-lymphoblastoid cell strains transformed by Epstein-Barr virus (EBV) from normal individuals and Werner's syndrome (WRN) patients were compared. We continuously passaged cell strains from 28 WRN patients and 20 normal individuals for about 2 years corresponding to over 160 population doubling levels (PDLs). First, the WRN mutation significantly suppressed the immortalization: all the 28 cell strains from WRN patients, as well as 15 out of 20 cell strains from normal individuals, died out before 160 PDLs mostly without developing a significant telomerase activity. The remaining five cell strains from normal individuals became moderately/strongly telomerase-positive and, three of them were apparently immortalized with an infinitively proliferating activity. Second, the monitoring of the telomere length of both normal and WRN cell strains during the culture period suggests that the WRN gene mutation causes abnormal dynamics of the telomere: (1) a significant proportion of WRN cell strains showed drastic shortening or lengthening of telomere lengths during cell passages compared with normal cell strains, and (2) WRN cell strains terminated their life-span at a wide range of telomere length (between 3.5 and 18.5 Kbp), whereas normal cell strains terminated within a narrow telomere length range (between 5.5 and 9 Kbp). The chromosomal aberration characteristic of WRN cells, including translocation was confirmed in our experiment. We discussed the correlation between the chromosomal instability, abnormal telomere dynamics and inability of immortalization of the WRN B-lymphobloastoid cell strains.

Progeroid syndromes: probing the molecular basis of aging?

A valid method of studying age related degenerative pathologies is to study human genetic diseases that appear to accelerate many, though not necessarily all, features of the aging process. Such diseases are described as progeroid syndromes because of their possible relevance to many aspects of aging and age related disease. This article describes the recent progress made at the cellular and molecular levels in understanding the pathogenesis of one of the best characterised of these disorders, Werner's syndrome. These observations are related to some of the less well characterised progeroid syndromes within the context of the cell senescence hypothesis of aging, a theory formulated to explain the aging of regenerative tissue in normal individuals.

Cycling Werner's syndrome fibroblasts display calcium-dependent potassium currents

Werner's Syndrome (WS) fibroblasts undergo premature senescence. Two hypotheses have been proposed to explain this phenomenon: (i) the phenotype is due to the overexpression of senescence-specific proteins in every cell in the population. Such proteins are known to suppress calcium-dependent potassium currents. (ii) The WS mutation greatly increases the proportion of cells that stop cycling at each generation and become senescent. If hypothesis (i) is correct, such currents should be suppressed in all WS fibroblasts; whereas hypothesis (ii) predicts that they will be retained in the cycling fraction of the population. To distinguish between these hypotheses whole-cell patch-clamp currents were recorded from cycling cells. Slowly activating outward calcium-dependent potassium currents were detected in both cycling WS and control fibroblasts. These findings support hypothesis (ii): the premature senescence of WS fibroblasts is due to an increased rate of transition from cycling to senescence in the total cell population.

Unexpectedly low loss of heterozygosity in genetically unstable Werner syndrome cell lines

We have determined the mitotic stability of micro- and mini-satellite DNA sequences in SV40-immortalized Werner syndrome (WS) and control fibroblast cell lines. Five microsatellite loci were genotyped in two WS and two control SV40-immortalized fibroblast cell lines and in 154 independent primary or secondary clones derived from these. We used four minisatellite "core" or individual locus probes in Southern blot hybridization analyses to assess minisatellite stability in WS and control clones. Microsatellite allele length was stably maintained in both WS and control cells, and an upper limit for the generation of new allele lengths was estimated to be < or = 4.5 x 10(-4)/allele/generation (or < or = 2.25 x 10(-5)/CA repeat/generation). In contrast to length stability, loss of heterozygosity (LOH) at microsatellite loci ranged up to 76% at the 13 informative locus:cell line combinations. An unexpected, and counterintuitive, finding was a much lower frequency of LOH in WS than in control clones at microsatellite loci on three different chromosomes. Minisatellite band alterations (gains, losses, or band intensity differences) were 4-fold lower in WS than in control cells. Our results suggest that the chromosomal and molecular genetic instability displayed by WS cells is unlikely to be the result of a micro- or mini-satellite destabilizing defect. A second, unexpected conclusion is that WS cells may possess a novel means of either suppressing or masking LOH events in the presence of constitutional cytogenetic and molecular genetic instability.

[Neurologic complications in a case of Werner syndrome]

A 39 year old caucasian man was admitted in 1994 to the neurological department with a left pure motor hemiplegia that appeared suddenly. This patient showed typical features of Werner's syndrome. He had a hoarse voice, a diffuse muscle weakness and atrophy in the upper and lower limbs with chronic ulcers on the legs. His scalp and public hair were sparse. Cranial MRI revealed several lesions in the white matter, low signal intensity on T1 weighted images and high signal on T2 weighted images. Cerebrospinal fluid (CSF was inflammatory with hypercytosis and proteinorachia was 0.50 g/l with synthesis of IgG. Sural nerve biopsy revealed muscle atrophy and the loss of myelinated fibers. Thus, central and peripheral nervous systems were affected in this case.

Werner syndrome: studies in an affected family reveal a cellular phenotype of unaffected siblings

Werner syndrome is an inherited disease with symptoms of presenescence. The primary defect site either on the protein or at the DNA level is not known, nor is it possible to identify a heterozygous phenotype. On the basis of cellular peculiarities expressed in the homozygotes-lifespan reduction of cells in culture, length of population doubling time and chromosomal instability-we searched for a 'Werner-like' phenotype in otherwise phenotypically unaffected siblings. We established primary fibroblasts from eight members of a Tyrolean family, two of whom had been diagnosed as typical Werner syndrome, as well as from unrelated healthy young and old volunteers. Determination of the lifespan of each strain and studies on population doubling time and chromosomal instability revealed similar cellular characteristics in all family members, albeit to a lesser extent with the siblings than with the homozygotes when compared to age-matched controls. These features, also apparent in cultivated fibroblasts from old but healthy controls, appear to be indicative of Werner syndrome when expressed in young or middle aged persons. The possible identification of otherwise clinically healthy gene carriers of Werner syndrome is of utmost importance for genetic counselling and medical surveillance for this disorder.

Accelerated loss of telomeric repeats may not explain accelerated replicative decline of Werner syndrome cells

The Werner syndrome (WS) is characterized by the premature onset and accelerated rate of development of major geriatric disorders, including atherosclerosis, diabetes mellitus, osteoporosis, ocular cataracts, and various neoplasms. Cultures of WS skin-fibroblastlike cells have been previously shown to undergo accelerated rates of decline of the replicative potentials and to exhibit variegated chromosomal translocations and deletions. Since the replicative decline of normal somatic cells is associated with a loss of telomeric repeats, we investigated the kinetics of telomeric repeat loss in WS cells. The mean length of telomere restriction fragments (TRF) from the earliest passages of WS cells studied was not shorter than those of controls, possibly reflecting selective pressure for subsets of cells with relatively high residual replicative capacity. Statistical evidence indicated an accelerated shortening of TRF length in serially passaged WS cultures, but the mean TRF lengths of WS cultures that had ceased replicating were significantly longer than those of senescent controls. Thus, while accelerated loss of telomeric repeats could potentially explain the rapid decline in proliferation of WS cells, it is possible that WS cells exit the cell cycle via mechanisms that differ from those of replicatively senescent cells from control subjects.

Premature aging in Werner's syndrome spares the central nervous system

Werner's Syndrome is a rare genetic disease, characterized by premature aging of many tissues and organs. We studied the brain morphology and function in two patients with Werner's syndrome to assess the possible involvement of the central nervous system in this premature aging process. The two patients (brother and sister, respectively) were studied by magnetic resonance imaging (MRI) and angiography (MRA), single photon emission computed tomography (SPECT) with (99mTc)-d,l-hexamethyl propilene amine oxime (HMPAO), positron emission tomography (PET) with 2(18F)-Fluoro-2-deoxyglucose (FDG), electroencephalography (EEG), and electromyography (EMG). Some of these investigations were also repeated after 1 year. The results of all these studies were normal. The premature aging process in patients with Werner's syndrome, while affecting most tissues, seems to spare the central nervous system.

A patient with Werner's syndrome and erythroleukemia: just coincidence?

Werner's syndrome is a rare clinical entity and approximately 150 cases have been reported in the medical literature. Werner's syndrome, inherited by autosomal recessive transmission, is characterized primarily by a short stature, premature greying and balding, trophic ulceration of the legs, diabetes mellitus and hypogonadism. These features combine to present a picture of adult progeria. In this brief report we describe a 51-year-old Bedouin male with Werner's syndrome, diagnosed as erythroleukemia (AML-6), and presenting as acute pancytopenia. The patient died two months after diagnosis. This is a rare case of erythroleukemia in a patient with Werner's syndrome. We survey current knowledge of the cytogenetic pathogenesis of Werner's syndrome and erythroleukemia, and attempt to explain the possible link between these two rare syndromes.