A Novel Variant in the WRN Gene Detected in a Case of Early-Onset Severe Insulin Resistance Displaying Some but Not All Hallmarks of Progeroid Werner Syndrome

OBJECTIVE

Determining the cause of severe insulin resistance and early-onset diabetes in the case of a young woman in which a wide range of differential diagnoses did not apply.

RESEARCH DESIGN AND METHODS

Diagnostic workup including medical history, physical examination, specialist consultations, imaging methods, laboratory assessment, and genetic testing carried out by next-generation panel sequencing.

RESULTS

After ruling out several differential diagnoses, genetic testing revealed a previously unknown homozygous variant within the canonical splice site of intron 4 in the WRN gene classified as pathogenic. Thus, although not all cardinal clinical criteria according to existing guidelines had been met, the phenotype of our patient was attributed to Werner syndrome (WS), an autosomal-recessive inherited progeroid syndrome.

CONCLUSIONS

WS, although rare, must be considered as a differential diagnosis in cases of severe insulin resistance. Moreover, recognized clinical criteria of WS may not lead to diagnosis in all cases.

The function of Bazhen decoction in rescuing progeroid cell senescence via facilitating G-quadruplex resolving and telomere elongation

ETHNOPHARMACOLOGICAL RELEVANCE

The Bazhen decoction is one of the most extensively used Traditional Chinese medicine (TCM) prescriptions for treatment of aging related diseases. However, due to the complexity of the components, the pharmacological mechanism of Bazhen decoction is still limited.

AIM OF THE STUDY

In this study, with the aim of helping the clinical precision medicine of TCM, we try out a systematic analysis for dissecting the molecular mechanism of complicated TCM prescription: Bazhen decoction. We identify the pharmacological mechanism of Bazhen decoction in telomere elongation as revealed by systematic analysis.

MATERIALS AND METHODS

By RNA sequencing and transcriptome analysis of Bazhen decoction treated wild type cells, we reveal the transcriptome profile induced by Bazhen decoction. We utilized the cells derived from Werner syndrome (WS) mice, which is known to be dysfunctional in telomere elongation due to the deficiency of DNA helicase Wrn. By Western blot, qPCR, Immunofluorescence, flow cytometry, telomere FISH, and SA-β-Gal staining, we verify the transcriptome data and confirm the pharmacological function of Bazhen decoction and its drug containing serum in telomere elongation and reversing progeroid cell senescence.

RESULTS

We reveal that Bazhen decoction may systematically regulate multiple anti-aging pathways, including stem cell regulation, protein homeostasis, cardiovascular function, neuronal function, anti-inflammation, anti-DNA damage induced stress, DNA helicase activity and telomere lengthening. We find that Bazhen decoction and its drug containing serum could up-regulate multiple DNA helicases and telomere regulating proteins. The increased DNA helicases promote the resolving of G-quadruplex (G4) structures, and facilitate DNA replication and telomere elongation. These improvements also endow the cellular resistance to DNA damages induced by replication stress, and rescue the WS caused cellular senescence.

CONCLUSIONS

Together these data suggest that Bazhen decoction up-regulate the expression of DNA helicases, thus facilitate G4 resolving and telomere maintenance, which rescue the progeroid cellular senescence and contribute to its anti-aging properties. Our data reveal a new molecular mechanism of Bazhen decoction in anti-aging related diseases via elongating telomere, this may shed light in the application of Bazhen decoction in multiple degenerative diseases caused by telomere erosion.

The identification of a novel mutation (p.I223fs) in WRN associated with Werner syndrome

PURPOSE

Werner syndrome (WS) is a rare autosomal recessive genetic disease caused by mutations in the WRN gene, and it is characterized by multiple manifestations corresponding to early-onset aging. This study reports the case of a WS patient with a novel WRN mutation.

PATIENT AND METHODS

A 36-year-old male patient with WS was evaluated after approval from the local ethics committee. The clinical and biochemical findings of the patient were described. Peripheral blood sample was collected to extract genomic DNA for WRN gene exome sequencing. The three-dimensional (3D) protein structural prediction analysis was performed via the AlphaFold 2.2 program and PyMol software.

RESULTS

We report the case of a clinically diagnosed WS patient with consanguineous parents who presented with complex manifestations including early-onset diabetes mellitus, binocular cataracts, cerebral infarction, cerebral atherosclerosis, hypertension, dyslipidemia, hypothyroidism, and suspected meningioma, accompanied by short stature, gray hair, rough skin with subcutaneous fat atrophy, a high-pitched voice, palmoplantar keratoderma, bilateral flat feet, and an indolent deep ulceration on the foot. Exome sequencing identified a novel homozygous frameshift mutation in the WRN gene, c.666-669 del TATT, p.I223fs. The 3D structure prediction showed that premature termination and significant structural changes could occur in the mutant WRN protein.

CONCLUSION

We identified a novel homozygous frameshift mutation, p.I223fs, in WRN in a Chinese patient with WS, expanding the spectrum of mutations in WS.

Senescence, regulators of alternative splicing and effects of trametinib treatment in progeroid syndromes

Progeroid syndromes such as Hutchinson Gilford Progeroid syndrome (HGPS), Werner syndrome (WS) and Cockayne syndrome (CS), result in severely reduced lifespans and premature ageing. Normal senescent cells show splicing factor dysregulation, which has not yet been investigated in syndromic senescent cells. We sought to investigate the senescence characteristics and splicing factor expression profiles of progeroid dermal fibroblasts. Natural cellular senescence can be reversed by application of the senomorphic drug, trametinib, so we also investigated its ability to reverse senescence characteristics in syndromic cells. We found that progeroid cultures had a higher senescence burden, but did not always have differences in levels of proliferation, DNA damage repair and apoptosis. Splicing factor gene expression appeared dysregulated across the three syndromes. 10 µM trametinib reduced senescent cell load and affected other aspects of the senescence phenotype (including splicing factor expression) in HGPS and Cockayne syndromes. Werner syndrome cells did not demonstrate changes in in senescence following treatment. Splicing factor dysregulation in progeroid cells provides further evidence to support this mechanism as a hallmark of cellular ageing and highlights the use of progeroid syndrome cells in the research of ageing and age-related disease. This study suggests that senomorphic drugs such as trametinib could be a useful adjunct to therapy for progeroid diseases.

Early-onset diabetes mellitus as a presenting feature of Werner's syndrome in an Indian family

BACKGROUND

Diabetes mellitus (DM) in children and adolescents is typically caused by type 1 DM, followed by type 2 DM and maturity-onset diabetes of the young (MODY). We report an unusual Asian Indian family in which three members presented with DM at ages 15, 20, and 30, but not fitting the typical clinical picture of type 1 DM, type 2 DM, or MODY. The primary objective was to elucidate the molecular genetic basis of DM in this family.

METHODS

The proband, a 22-year-old man, had short stature, gray hair, osteoporosis, and markedly reduced subcutaneous fat on the body, especially on the extremities along with acanthosis nigricans, and developed myxoid malignant peripheral nerve sheath tumor. Detailed family history revealed multiple loops of consanguinity. The proband underwent whole-genome sequencing, and seven relatives underwent whole-exome sequencing.

RESULTS

The proband and three additional family members were found to have the homozygous c.561A>G nucleotide variant of WRN RecQ-like helicase (WRN) gene consistent with the diagnosis of Werner's syndrome. The c.561A>G variant induces a new splicing site on exon 6 resulting in a truncated WRN protein, p.Lys187Trpfs*13.

CONCLUSION

Our report brings to attention the onset of DM during childhood or early adulthood in patients with Werner's syndrome who typically develop type 2 DM around the age of 30-40 years. Presence of consanguinity among parents, dysmorphic features, and malignancy should prompt consideration of diagnosis of Werner's syndrome.

Sex differences in symptom presentation and their impact on diagnostic accuracy in Werner syndrome

AIM

Whether sex differences exist in hereditary progeroid syndromes remains unclear. In this study, we investigated sex differences in patients with Werner syndrome (WS), a model of human aging, using patient data at the time of diagnosis.

METHODS

The presence of six cardinal signs in the diagnostic criteria was retrospectively evaluated.

RESULTS

We found that the percentage of patients with all cardinal signs was higher in males than in females (54.2% vs. 21.2%). By the age of 40 years, 57.1% of male patients with WS presented with all the cardinal signs, whereas none of the female patients developed all of them. In particular, the frequency of having a high-pitched, hoarse voice, a characteristic of WS, was lower in female patients. The positive and negative predictive values for clinical diagnosis were 100% for males and females, indicating the helpfulness of diagnostic criteria regardless of sex. More female patients than male (86.7% vs. 64%) required genetic testing for their diagnosis because their clinical symptoms were insufficient, suggesting the importance of genetic testing for females even if they do not show typical symptoms of WS. Finally, the frequency of abnormal voice was lower in patients with WS harboring the c.3139-1G > C homozygous mutation.

CONCLUSION

These results indicate, for the first time, that there are sex differences in the phenotypes of hereditary progeroid syndromes. The analysis of this mechanism in this human model of aging may lead to the elucidation of sex differences in the various symptoms of normal human aging. Geriatr Gerontol Int 2024; 24: 161-167.

Werner syndrome associated with poorly differentiated thyroid carcinoma and systemic sclerosis-like skin manifestations: A case report

Werner syndrome (WS) is an autosomal recessive disorder characterised by premature ageing. WS patients often experience scleroderma-like manifestation including skin sclerosis and skin ulcer, making it difficult to differentiate WS from systemic sclerosis (SSc). Moreover, there is a high incidence of malignancy and arteriosclerosis-related disease in WS patients. We herein describe a 36-year-old woman with WS who had poorly differentiated thyroid carcinoma, one of the rare phenotypes of thyroid tumour. This case suggested the importance to distinguish WS from SSc and early diagnosis of malignancy.

Senescence-associated inflammation and inhibition of adipogenesis in subcutaneous fat in Werner syndrome

Werner syndrome (WS) is a hereditary premature aging disorder characterized by visceral fat accumulation and subcutaneous lipoatrophy, resulting in severe insulin resistance. However, its underlying mechanism remains unclear. In this study, we show that senescence-associated inflammation and suppressed adipogenesis play a role in subcutaneous adipose tissue reduction and dysfunction in WS. Clinical data from four Japanese patients with WS revealed significant associations between the decrease of areas of subcutaneous fat and increased insulin resistance measured by the glucose clamp. Adipose-derived stem cells from the stromal vascular fraction derived from WS subcutaneous adipose tissues (WSVF) showed early replicative senescence and a significant increase in the expression of senescence-associated secretory phenotype (SASP) markers. Additionally, adipogenesis and insulin signaling were suppressed in WSVF, and the expression of adipogenesis suppressor genes and SASP-related genes was increased. Rapamycin, an inhibitor of the mammalian target of rapamycin (mTOR), alleviated premature cellular senescence, rescued the decrease in insulin signaling, and extended the lifespan of WS model of C. elegans. To the best of our knowledge, this study is the first to reveal the critical role of cellular senescence in subcutaneous lipoatrophy and severe insulin resistance in WS, highlighting the therapeutic potential of rapamycin for this disease.

Breast cancer in a Hispanic patient with Werner syndrome

Werner Syndrome is a rare autosomal recessive condition characterized by premature aging and increased risk of malignancies due to gene mutations associated with DNA stability. We present the first case report of a 29-year-old Hispanic female with WS diagnosed with breast cancer. Diagnostic mammography and ultrasound, breast MRI and PET examinations revealed two lesions biopsy proven as invasive ductal carcinoma. The patient underwent neoadjuvant chemotherapy and radical mastectomy. Recurrence occurred 10 months postoperatively with molecular analysis demonstrating TP53 mutations. The multifactorial assessment of breast cancer in this case study is crucial towards optimizing screening, diagnosis and management of this disease in patients with WS.

A Patient with Werner's Syndrome Who Underwent Aortic Valve Replacement through Minimally Invasive Cardiac Surgery

Werner's syndrome (WS) is a genetic disorder presenting with premature senility. In the present study, we performed minimally invasive cardiac surgery (MICS)-aortic valve replacement (AVR) on a patient with Werner's syndrome who presented with aortic stenosis. The patient, a 49-year-old Japanese man, was brought to the emergency room with dyspnea during exercise. On echocardiography, severe aortic stenosis was found and surgery was planned. He had poorly controlled diabetes mellitus and underwent MICS-AVR to avoid the risk of sternal osteomyelitis, which resulted in a good outcome. The aortic valve had sclerotic changes and a genetic disease was suspected based on the onset of aortic stenosis at a young age, characteristic appearance, and various signs of aging. Genetic testing led to the diagnosis of WS.

A rare syndrome mimicking scleroderma: Werner syndrome

Werner syndrome (WS), also known as adult progeria, is a premature ageing syndrome that can manifest itself with grey hair, hair loss, diabetes mellitus, hyperlipidaemia, hypertension, skin disorders, ocular cataracts, myocardial infarction, osteoporosis, and stroke, especially after puberty. Physical examination findings similar to systemic sclerosis may be seen. Therefore, it may mimic this disease as misleading. A 43-year-old female patient was admitted to our clinic with a pre-diagnosis of systemic sclerosis complaint of skin hardening up to the ankle. In the first physical examination, there were wrinkles and thinning of the lip, suggesting systemic sclerosis in the facial appearance. On her capillaroscopy, there was tortuosity and an old focus of microhemorrhage. She had a history of diabetes mellitus and chronic osteomyelitis. When all symptoms, clinical findings, and antibody results were combined, it was thought that the patient might have WS. WS was diagnosed with homozygous c.2221 C>P p.R741*(rs763089663) positive in genetic analysis. It is known that WS creates a predisposition to malignancies, and most patients die secondary to malignancies. Therefore, early diagnosis becomes essential. Early diagnosis is of vital importance both to prevent complications and to delay treatment. In particular, systemic sclerosis-like findings of this syndrome may cause delays in diagnosis. For this reason, small clues suggesting WS in the clinic should be well known and well defined.

DNA methylation signatures in Blood DNA of Hutchinson-Gilford Progeria syndrome

Hutchinson-Gilford Progeria Syndrome (HGPS) is an extremely rare genetic disorder caused by mutations in the LMNA gene and characterized by premature and accelerated aging beginning in childhood. In this study, we performed the first genome-wide methylation analysis on blood DNA of 15 patients with progeroid laminopathies using Infinium Methylation EPIC arrays including 8 patients with classical HGPS. We could observe DNA methylation alterations at 61 CpG sites as well as 32 significant regions following a 5 Kb tiling analysis. Differentially methylated probes were enriched for phosphatidylinositol biosynthetic process, phospholipid biosynthetic process, sarcoplasm, sarcoplasmic reticulum, phosphatase regulator activity, glycerolipid biosynthetic process, glycerophospholipid biosynthetic process, and phosphatidylinositol metabolic process. Differential methylation analysis at the level of promoters and CpG islands revealed no significant methylation changes in blood DNA of progeroid laminopathy patients. Nevertheless, we could observe significant methylation differences in classic HGPS when specifically looking at probes overlapping solo-WCGW partially methylated domains. Comparing aberrantly methylated sites in progeroid laminopathies, classic Werner syndrome, and Down syndrome revealed a common significantly hypermethylated region in close vicinity to the transcription start site of a long non-coding RNA located anti-sense to the Catenin Beta Interacting Protein 1 gene (CTNNBIP1). By characterizing epigenetically altered sites, we identify possible pathways/mechanisms that might have a role in the accelerated aging of progeroid laminopathies.

Case Report: A novel WRN mutation in Werner syndrome patient with diabetic foot disease and myelodysplastic syndrome

Werner syndrome is an autosomal recessive rare disease caused by a WRN gene mutation, which is rarely reported in the Chinese population. We report the clinical and genetic data of a Chinese patient with Werner syndrome. The proband was a 40-year-old male patient who presented with diabetic foot ulcers, accompanied by short stature, cataracts, hypogonadism, and hair thinning, and myelodysplastic syndrome (MDS) occurred after 18 months. Genetic sequencing showed there were compound heterozygous mutations as c.3384-1G>C and c.3744dupA in the WRN gene. The c.3744dupA mutation is a novel pathogenic variation for Werner syndrome.

Characterization of Stress Responses in a Drosophila Model of Werner Syndrome

As organisms age, their resistance to stress decreases while their risk of disease increases. This can be shown in patients with Werner syndrome (WS), which is a genetic disease characterized by accelerated aging along with increased risk of cancer and metabolic disease. WS is caused by mutations in WRN, a gene involved in DNA replication and repair. Recent research has shown that WRN mutations contribute to multiple hallmarks of aging including genomic instability, telomere attrition, and mitochondrial dysfunction. However, questions remain regarding the onset and effect of stress on early aging. We used a fly model of WS (WRNexoΔ) to investigate stress response during different life stages and found that stress sensitivity varies according to age and stressor. While larvae and young WRNexoΔ adults are not sensitive to exogenous oxidative stress, high antioxidant activity suggests high levels of endogenous oxidative stress. WRNexoΔ adults are sensitive to stress caused by elevated temperature and starvation suggesting abnormalities in energy storage and a possible link to metabolic dysfunction in WS patients. We also observed higher levels of sleep in aged WRNexoΔ adults suggesting an additional adaptive mechanism to protect against age-related stress. We suggest that stress response in WRNexoΔ is multifaceted and evokes a systemic physiological response to protect against cellular damage. These data further validate WRNexoΔ flies as a WS model with which to study mechanisms of early aging and provide a foundation for development of treatments for WS and similar diseases.

MUT-7 Provides Molecular Insight into the Werner Syndrome Exonuclease

Werner syndrome (WS) is a rare recessive genetic disease characterized by premature aging. Individuals with this disorder develop normally during childhood, but their physiological conditions exacerbate the aging process in late adolescence. WS is caused by mutation of the human WS gene (WRN), which encodes two main domains, a 3′-5′ exonuclease and a 3′-5′ helicase. Caenorhabditis elegans expresses human WRN orthologs as two different proteins: MUT-7, which has a 3′-5′ exonuclease domain, and C. elegans WRN-1 (CeWRN-1), which has only helicase domains. These unique proteins dynamically regulate olfactory memory in C. elegans, providing insight into the molecular roles of WRN domains in humans. In this review, we specifically focus on characterizing the function of MUT-7 in small interfering RNA (siRNA) synthesis in the cytoplasm and the roles of siRNA in directing nuclear CeWRN-1 loading onto a heterochromatin complex to induce negative feedback regulation. Further studies on the different contributions of the 3′-5′ exonuclease and helicase domains in the molecular mechanism will provide clues to the accelerated aging processes in WS.

Human WRN is an intrinsic inhibitor of progerin, abnormal splicing product of lamin A

Werner syndrome (WRN) is a rare progressive genetic disorder, caused by functional defects in WRN protein and RecQ4L DNA helicase. Acceleration of the aging process is initiated at puberty and the expected life span is approximately the late 50 s. However, a Wrn-deficient mouse model does not show premature aging phenotypes or a short life span, implying that aging processes differ greatly between humans and mice. Gene expression analysis of WRN cells reveals very similar results to gene expression analysis of Hutchinson Gilford progeria syndrome (HGPS) cells, suggesting that these human progeroid syndromes share a common pathological mechanism. Here we show that WRN cells also express progerin, an abnormal variant of the lamin A protein. In addition, we reveal that duplicated sequences of human WRN (hWRN) from exon 9 to exon 10, which differ from the sequence of mouse WRN (mWRN), are a natural inhibitor of progerin. Overexpression of hWRN reduced progerin expression and aging features in HGPS cells. Furthermore, the elimination of progerin by siRNA or a progerin-inhibitor (SLC-D011 also called progerinin) can ameliorate senescence phenotypes in WRN fibroblasts and cardiomyocytes, derived from WRN-iPSCs. These results suggest that progerin, which easily accumulates under WRN-deficient conditions, can lead to premature aging in WRN and that this effect can be prevented by SLC-D011.

Severe metabolic disorders coexisting with Werner syndrome: a case report

Werner syndrome, also called adult progeria, is a heritable autosomal recessive human disorder characterized by the premature onset of numerous age-related diseases including juvenile cataracts, dyslipidemia, diabetes mellitus (DM), osteoporosis, atherosclerosis, and cancer. Werner syndrome is a segmental progeroid syndrome whose presentation resembles accelerated aging. The most common causes of death for WS patients are atherosclerosis and cancer. A 40-year-old female presented with short stature, bird-like facies, canities with alopecia, scleroderma-like skin changes, and non-healing foot ulcers. The patient reported a history of delayed puberty, abortion, hypertriglyceridemia, and juvenile cataracts. A clinical diagnosis of WS was made and subsequently confirmed. We discovered two WRN gene mutations in the patient, Variant 1 was the most common WRN mutation, nonsense mutation (c.1105C>T:p.R369Ter) in exon 9, which caused a premature termination codon (PTC) at position 369. Variant 2 was a frameshift mutation (c.1134delA:p.E379KfsTer5) in exon 9, which caused a PTC at position 383 and has no published reports describing. Patients with WS can show a wide variety of clinical and biological manifestations in endocrine-metabolic systems (DM, thyroid dysfunction, and hyperlipidemia). Doctors must be cognizant of early manifestations of WS and treatment options.

Review of How Genetic Research on Segmental Progeroid Syndromes Has Documented Genomic Instability as a Hallmark of Aging But Let Us Now Pursue Antigeroid Syndromes!

The purpose of this early contribution to the new Fellows Forum of this pioneering journal for what is now called Geroscience is to provide an example of how the author's interest in using the emerging tools of human genetics has led to strong support for one of the hallmarks of aging-Genomic Instability. We shall also briefly review our emerging interests in the genetic analysis of what we have called Antigeroid Syndromes. While there has been significant progress in that direction via genetic studies of centenarians, the search for genetic pathways that make individuals unusually resistant or resilient to the ravages of specific geriatric disorders has been comparatively neglected. We refer to these disorders as Unimodal Antigeroid Syndromes. It is our hope that our young colleagues will consider research efforts in that direction.

Genetic Mutations and Variants in the Susceptibility of Familial Non-Medullary Thyroid Cancer

Thyroid cancer is the most frequent endocrine malignancy with the majority of cases derived from thyroid follicular cells and caused by sporadic mutations. However, when at least two or more first degree relatives present thyroid cancer, it is classified as familial non-medullary thyroid cancer (FNMTC) that may comprise 3-9% of all thyroid cancer. In this context, 5% of FNMTC are related to hereditary syndromes such as Cowden and Werner Syndromes, displaying specific genetic predisposition factors. On the other hand, the other 95% of cases are classified as non-syndromic FNMTC. Over the last 20 years, several candidate genes emerged in different studies of families worldwide. Nevertheless, the identification of a prevalent polymorphism or germinative mutation has not progressed in FNMTC. In this work, an overview of genetic alteration related to syndromic and non-syndromic FNMTC is presented.

METTL3 counteracts premature aging via m6A-dependent stabilization of MIS12 mRNA

N6-Methyladenosine (m6A) messenger RNA methylation is a well-known epitranscriptional regulatory mechanism affecting central biological processes, but its function in human cellular senescence remains uninvestigated. Here, we found that levels of both m6A RNA methylation and the methyltransferase METTL3 were reduced in prematurely senescent human mesenchymal stem cell (hMSC) models of progeroid syndromes. Transcriptional profiling of m6A modifications further identified MIS12, for which m6A modifications were reduced in both prematurely senescent hMSCs and METTL3-deficient hMSCs. Knockout of METTL3 accelerated hMSC senescence whereas overexpression of METTL3 rescued the senescent phenotypes. Mechanistically, loss of m6A modifications accelerated the turnover and decreased the expression of MIS12 mRNA while knockout of MIS12 accelerated cellular senescence. Furthermore, m6A reader IGF2BP2 was identified as a key player in recognizing and stabilizing m6A-modified MIS12 mRNA. Taken together, we discovered that METTL3 alleviates hMSC senescence through m6A modification-dependent stabilization of the MIS12 transcript, representing a novel epitranscriptional mechanism in premature stem cell senescence.

Diabetes mellitus coexisted with progeria: a case report of atypical Werner syndrome with novel LMNA mutations and literature review

Werner syndrome (WS) is a rare, adult-onset progeroid syndrome. Classic WS is caused by WRN mutation and partial atypical WS (AWS) is caused by LMNA mutation. A 19-year-old female patient with irregular menstruation and hyperglycemia was admitted. Physical examination revealed characteristic faces of progeria, graying and thinning of the hair scalp, thinner and atrophic skin over the hands and feet, as well as lipoatrophy of the extremities, undeveloped breasts at Tanner stage 3, and short stature. The patient also suffered from severe insulin-resistant diabetes mellitus, hyperlipidemia, fatty liver, and polycystic ovarian morphology. Possible WS was considered and both WRN and LMNA genes were analyzed. A novel missense mutation p.L140Q (c.419T>A) in the LMNA gene was identified and confirmed the diagnosis of AWS. Her father was a carrier of the same mutation. We carried out therapy for lowering blood glucose and lipid and improving insulin resistance, et al. The fasting glucose, postprandial glucose and triglyceride level was improved after treatment for 9 days. Literature review of AWS was performed to identify characteristics of the disease. Diabetes mellitus is one of the clinical manifestations of WS and attention must give to the differential diagnosis. Gene analysis is critical in the diagnosis of WS. According to the literature, classic and atypical WS differ in incidence, pathogenic gene, and clinical manifestations. Characteristic dermatological pathology may be significantly more important for the initial identification of AWS. Early detection, appropriate treatments, and regular follow-up may improve prognosis and survival of WS patients.

NAD+ augmentation restores mitophagy and limits accelerated aging in Werner syndrome

Metabolic dysfunction is a primary feature of Werner syndrome (WS), a human premature aging disease caused by mutations in the gene encoding the Werner (WRN) DNA helicase. WS patients exhibit severe metabolic phenotypes, but the underlying mechanisms are not understood, and whether the metabolic deficit can be targeted for therapeutic intervention has not been determined. Here we report impaired mitophagy and depletion of NAD+, a fundamental ubiquitous molecule, in WS patient samples and WS invertebrate models. WRN regulates transcription of a key NAD+ biosynthetic enzyme nicotinamide nucleotide adenylyltransferase 1 (NMNAT1). NAD+ repletion restores NAD+ metabolic profiles and improves mitochondrial quality through DCT-1 and ULK-1-dependent mitophagy. At the organismal level, NAD+ repletion remarkably extends lifespan and delays accelerated aging, including stem cell dysfunction, in Caenorhabditis elegans and Drosophila melanogaster models of WS. Our findings suggest that accelerated aging in WS is mediated by impaired mitochondrial function and mitophagy, and that bolstering cellular NAD+ levels counteracts WS phenotypes.

Current Knowledge of Germline Genetic Risk Factors for the Development of Non-Medullary Thyroid Cancer

The thyroid is the most common site of endocrine cancer. One type of thyroid cancer, non-medullary thyroid cancer (NMTC), develops from follicular cells and represents approximately 90% of all thyroid cancers. Approximately 5%–15% of NMTC cases are thought to be of familial origin (FNMTC), which is defined as the occurrence of the disease in three or more first-degree relatives of the patient. It is often divided into two groups: Syndrome-associated and non-syndromic. The associated syndromes include Cowden syndrome, familial adenomatous polyposis, Gardner syndrome, Carney complex and Werner syndrome. The hereditary factors contributing to the unfavorable course of FNMTC remain poorly understood; therefore, considerable effort is being expended to identify contributing loci. Research carried out to date identifies fourteen genes (DICER1, FOXE1, PTCSC2, MYH9, SRGAP1, HABP2, BRCA1, CHEK2, ATM, RASAL1, SRRM2, XRCC1, TITF-1/NKX2.1, PTCSC3) associated with vulnerability to FNMTC that are not related to hereditary syndromes. In this review, we summarize FNMTC studies to date, and provide information on genes involved in the development of non-syndromic familial non-medullary thyroid cancers, and the significance of mutations in these genes as risk factors. Moreover, we discuss whether the genetic polymorphism rs966423 in DIRC3 has any potential as a prognostic factor of papillary thyroid cancer.

Characteristic Clinical Features of Werner Syndrome with a Novel Compound Heterozygous WRN Mutation c.1720+1G>A Plus c.3139-1G>C

Werner syndrome (WS) is an autosomal recessive progeroid disorder caused by mutations in the WRN gene (WRN). Most Japanese WS patients are born from a consanguineous marriage with homozygous WRN mutations. We herein report a rare WS patient born from non-consanguineous parents with compound heterozygous WRN mutations with a novel heterogeneous c.1720+1G>A substitution plus the most frequent heterogeneous c.3139-1G>C substitution among Japanese. Although the present case showed clinical characteristics common to previous Japanese WS patients, he had not developed any malignant tumors as of 43 years of age, suggesting that WS patients with this particular genetic mutation have a different phenotype than others.

Accelerated aging and aging process in the brain

One of the approaches to the research of the problem of aging is the study of genetic pathologies leading to accelerated aging, such as the Hutchinson-Gilford progeria syndrome, Werner syndrome, and Down syndrome. Probably, this approach can be used in an attempt to understand the neuronal mechanisms underlying normal and pathological brain aging. The analysis of the current state of scientific knowledge about these pathologies shows that in the Hutchinson-Gilford progeria and Werner syndrome, the rate of brain aging is significantly lower than the rate of whole body aging, whereas in Down syndrome, the brain ages faster than other organs due to amyloid-beta accumulation and chronic oxidative stress in the brain tissue. The main point of a previously proposed hypothesis is that the aging of higher animals and humans is associated with an increased level of reactive oxygen species in mitochondria with age, which activates apoptosis, thus reducing the number of functioning cells.

Recurrent skin ulcer cross-repair and sensory reconstruction in a WRN gene mutational patient

A 37-year-old man complained of a refractory posterior malleolar ulceration on his left ankle. He was diagnosed with Werner syndrome according to the progeroid clinical features and genetic testing. To approach the ulceration, a free flow-through right anterolateral thigh perforator flap with anterolateral thigh cutaneous nerve was harvested. One year later, he was readmitted due to a new ulceration on his right ankle. We harvested the left anterolateral thigh perforator flap with anterolateral thigh cutaneous nerve to reconstruct the defect. After one more year of follow-up, there was no recurrence of ulcers, and the sensation of the flap recovered partially after 6 months. We conclude that free flow-through anterolateral thigh perforator flap is a feasible choice for the repair of foot ulcers in Werner syndrome.

Everolimus rescues multiple cellular defects in laminopathy-patient fibroblasts

LMNA encodes the A-type lamins that are part of the nuclear scaffold. Mutations in LMNA can cause a variety of disorders called laminopathies, including Hutchinson-Gilford progeria syndrome (HGPS), atypical Werner syndrome, and Emery-Dreifuss muscular dystrophy. Previous work has shown that treatment of HGPS cells with the mTOR inhibitor rapamycin or with the rapamycin analog everolimus corrects several of the phenotypes seen at the cellular level-at least in part by increasing autophagy and reducing the amount of progerin, the toxic form of lamin A that is overproduced in HGPS patients. Since other laminopathies also result in production of abnormal and potentially toxic lamin proteins, we hypothesized that everolimus would also be beneficial in those disorders. To test this, we applied everolimus to fibroblast cell lines from six laminopathy patients, each with a different mutation in LMNA Everolimus treatment increased proliferative ability and delayed senescence in all cell lines. In several cell lines, we observed that with treatment, there is a significant improvement in nuclear blebbing, which is a cellular hallmark of HGPS and other lamin disorders. These preclinical results suggest that everolimus might have clinical benefit for multiple laminopathy syndromes.

Vitamin C alters the amount of specific endoplasmic reticulum associated proteins involved in lipid metabolism in the liver of mice synthesizing a nonfunctional Werner syndrome (Wrn) mutant protein

Werner syndrome (WS) is a premature aging disorder caused by mutations in a protein containing both a DNA exonuclease and DNA helicase domain. Mice lacking the helicase domain of the Wrn protein orthologue exhibit transcriptomic and metabolic alterations, some of which are reversed by vitamin C. Recent studies on these animals indicated that the mutant protein is associated with enriched endoplasmic reticulum (ER) fractions of tissues resulting in an ER stress response. In this study, we identified proteins that exhibit actual level differences in the ER enriched fraction between the liver of wild type and Wrn mutant mice using quantitative proteomic profiling with label-free Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). Multiple Reaction Monitoring (MRM) and immunoblotting were performed to validate findings in a secondary independent cohort of wild type and Wrn mutant mice. DAVID 6.7 (NIH) was used for functional annotation analysis and indicated that the identified proteins exhibiting level changes between untreated wild type, Wrn mutant, and vitamin C treated Wrn mutant mice (ANOVA P–value < 0.05) were involved in fatty acid and steroid metabolism pathways (Bonferroni P-value = 0.0137). Finally, when we compared the transcriptomic and the proteomic data of our mouse cohorts only ~7% of the altered mRNA profiles encoding for ER gene products were consistent with their corresponding protein profiles measured by the label-free quantification methods. These results suggest that a great number of ER gene products are regulated at the post-transcriptional level in the liver of Wrn mutant mice exhibiting an ER stress response.

Werner syndrome (WRN) gene variants and their association with altered function and age-associated diseases

Werner syndrome (WS) is a heritable autosomal recessive human disorder characterized by the premature onset of several age-associated pathologies including cancer. The protein defective in WS patients, WRN, is encoded by a member of the human RECQ gene family that contains both a DNA exonuclease and a helicase domain. WRN has been shown to participate in several DNA metabolic pathways including DNA replication, recombination and repair, as well as telomere maintenance and transcription modulation. Here we review base pair-level genetic variation that has been documented in WRN, with an emphasis on non-synonymous coding single nucleotide polymorphisms (SNPs) and their associations with anthropomorphic features, longevity and disease risk. These associations have been challenging to identify, as many reported WRN SNP associations appear to be further conditioned upon ethnic, age, gender or other environmental co-variables. The WRN variant phenotypic associations identified to date are intriguing, and several are of clear clinical import. Consequently, it will be important to extend these initial associations and to identify the mechanisms and conditions under which specific WRN variants may compromise WRN function to drive cellular and organismal phenotypes as well as disease risk.

Tumor Syndromes That Include Bone Tumors: An Update

Tumor syndromes, including bone neoplasias, are genetic predisposing conditions characterized by the development of a pattern of malignancies within a family at an early age of onset. Occurrence of bilateral, multifocal, or metachronous neoplasias and specific histopathologic findings suggest a genetic predisposition syndrome. Additional clinical features not related to the neoplasia can be a hallmark of specific genetic syndromes. Mostly, those diseases have an autosomal dominant pattern of inheritance with variable percentage of penetrance. Some syndromic disorders with an increased tumor risk may show an autosomal recessive transmission or are related to somatic mosaicism. Many genetic tumor syndromes are known. This update is specifically focused on syndromes predisposing to osteosarcoma and chondrosarcoma.

Homozygosity for the WRN Helicase-Inactivating Variant, R834C, does not confer a Werner syndrome clinical phenotype

Loss-of-function mutations in the WRN helicase gene cause Werner syndrome- a progeroid syndrome with an elevated risk of cancer and other age-associated diseases. Large numbers of single nucleotide polymorphisms have been identified in WRN. We report here the organismal, cellular, and molecular phenotypes of variant rs3087425 (c. 2500C > T) that results in an arginine to cysteine substitution at residue 834 (R834C) and up to 90% reduction of WRN helicase activity. This variant is present at a high (5%) frequency in Mexico, where we identified 153 heterozygous and three homozygous individuals among 3,130 genotyped subjects. Family studies of probands identified ten additional TT homozygotes. Biochemical analysis of WRN protein purified from TT lymphoblast cell lines confirmed that the R834C substitution strongly and selectively reduces WRN helicase, but not exonuclease activity. Replication track analyses showed reduced replication fork progression in some homozygous cells following DNA replication stress. Among the thirteen TT homozygotes, we identified a previously unreported and statistically significant gender bias in favor of males (p = 0.0016), but none of the clinical findings associated with Werner syndrome. Our results indicate that WRN helicase activity alone is not rate-limiting for the development of clinical WS.

Neurodegeneration in accelerated aging

The growing proportion of elderly people represents an increasing economic burden, not least because of age-associated diseases that pose a significant cost to the health service. Finding possible interventions to age-associated disorders therefore have wide ranging implications. A number of genetically defined accelerated aging diseases have been characterized that can aid in our understanding of aging. Interestingly, all these diseases are associated with defects in the maintenance of our genome. A subset of these disorders, Cockayne syndrome, Xeroderma pigmentosum group A and ataxia-telangiectasia, show neurological involvement reminiscent of what is seen in primary human mitochondrial diseases. Mitochondria are the power plants of the cells converting energy stored in oxygen, sugar, fat, and protein into ATP, the energetic currency of our body. Emerging evidence has linked this organelle to aging and finding mitochondrial dysfunction in accelerated aging disorders thereby strengthens the mitochondrial theory of aging. This theory states that an accumulation of damage to the mitochondria may underlie the process of aging. Indeed, it appears that some accelerated aging disorders that show neurodegeneration also have mitochondrial dysfunction. The mitochondrial alterations may be secondary to defects in nuclear DNA repair. Indeed, nuclear DNA damage may lead to increased energy consumption, alterations in mitochondrial ATP production and defects in mitochondrial recycling, a term called mitophagy. These changes may be caused by activation of poly-ADP-ribose-polymerase 1 (PARP1), an enzyme that responds to DNA damage. Upon activation PARP1 utilizes key metabolites that attenuate pathways that are normally protective for the cell. Notably, pharmacological inhibition of PARP1 or reconstitution of the metabolites rescues the changes caused by PARP1 hyperactivation and in many cases reverse the phenotypes associated with accelerated aging. This implies that modulation of PARP1 or the downstream metabolites may be a therapeutic strategy for treating accelerated aging disorders and potentially age-associated neurological decline seen in the normal population.

WRN Mutation Update: Mutation Spectrum, Patient Registries, and Translational Prospects

Werner syndrome (WS) is a rare autosomal recessive disorder characterized by a constellation of adult onset phenotypes consistent with an acceleration of intrinsic biological aging. It is caused by pathogenic variants in the WRN gene, which encodes a multifunctional nuclear protein with exonuclease and helicase activities. WRN protein is thought to be involved in optimization of various aspects of DNA metabolism, including DNA repair, recombination, replication, and transcription. In this update, we summarize a total of 83 different WRN mutations, including eight previously unpublished mutations identified by the International Registry of Werner Syndrome (Seattle, WA) and the Japanese Werner Consortium (Chiba, Japan), as well as 75 mutations already reported in the literature. The Seattle International Registry recruits patients from all over the world to investigate genetic causes of a wide variety of progeroid syndromes in order to contribute to the knowledge of basic mechanisms of human aging. Given the unusually high prevalence of WS patients and heterozygous carriers in Japan, the major goal of the Japanese Consortium is to develop effective therapies and to establish management guidelines for WS patients in Japan and elsewhere. This review will also discuss potential translational approaches to this disorder, including those currently under investigation.

[Molecular mechanism of pathogenesis of the progeria]

Hutchinson-Gilford progeria syndrome (HGPS) and Werner syndrome (WS) exhibit accelerated aging phenotypes, which are caused by mutations in the LMNA or WRN genes, respectively. Accumulating evidence suggested that the mutations commonly caused senes- cent phenotypes such as DNA damage, cell cycle arrest, nuclear enlargement and nuclear shape abnormality. Furthermore, both mutations showed significant loss of nuclear lamina -binding proteins, a heterochromatin protein, and an epigenetic H3K9me3 mark in hetero- chromatin loci. These biochemical deficits might explain common molecular mechanism underlying the pathogenesis of the progeria.

Werner syndrome through the lens of tissue and tumour genomics

Werner syndrome (WS) is the canonical adult human progeroid ('premature aging') syndrome. Patients with this autosomal recessive Mendelian disorder display constitutional genomic instability and an elevated risk of important age-associated diseases including cancer. Remarkably few analyses of WS patient tissue and tumors have been performed to provide insight into WS disease pathogenesis or the high risk of neoplasia. We used autopsy tissue from four mutation-typed WS patients to characterize pathologic and genomic features of WS, and to determine genomic features of three neoplasms arising in two of these patients. The results of these analyses provide new information on WS pathology and genomics; provide a first genomic characterization of neoplasms arising in WS; and provide new histopathologic and genomic data to test several popular models of WS disease pathogenesis.

Association of the rs1346044 Polymorphism of the Werner Syndrome Gene RECQL2 with Increased Risk and Premature Onset of Breast Cancer

Like other RECQ helicases, WRN/RECQL2 plays a crucial role in DNA replication and the maintenance of genome stability. Inactivating mutations in RECQL2 lead to Werner syndrome, a rare autosomal disease associated with premature aging and an increased susceptibility to multiple cancer types. We analyzed the association of two coding single-nucleotide polymorphisms in WRN, Cys1367Arg (rs1346044), and Arg834Cys (rs3087425), with the risk, age at onset, and clinical subclasses of breast cancer in a hospital-based case-control study of an Austrian population of 272 breast cancer patients and 254 controls. Here we report that the rare homozygous CC genotype of rs1346044 was associated with an approximately two-fold elevated breast cancer risk. Moreover, patients with the CC genotype exhibited a significantly increased risk of developing breast cancer under the age of 55 in both recessive and log-additive genetic models. CC patients developed breast cancer at a mean age of 55.2 ± 13.3 years and TT patients at 60.2 ± 14.7 years. Consistently, the risk of breast cancer was increased in pre-menopausal patients in the recessive model. These findings suggest that the CC genotype of WRN rs1346044 may contribute to an increased risk and a premature onset of breast cancer.

Metabolic and Phenotypic Differences between Mice Producing a Werner Syndrome Helicase Mutant Protein and Wrn Null Mice

Werner syndrome (WS) is a premature aging disorder caused by mutations in a RecQ-family DNA helicase, WRN. Mice lacking part of the helicase domain of the WRN orthologue exhibit many phenotypic features of WS, including metabolic abnormalities and a shorter mean life span. In contrast, mice lacking the entire Wrn protein (i.e. Wrn null mice) do not exhibit a premature aging phenotype. In this study, we used a targeted mass spectrometry-based metabolomic approach to identify serum metabolites that are differentially altered in young Wrn helicase mutant and Wrn null mice. An antibody-based quantification of 43 serum cytokines and markers of cardiovascular disease risk complemented this study. We found that Wrn helicase mutants exhibited elevated and decreased levels, respectively, of the anti-inflammatory cytokine IL-10 and the pro-inflammatory cytokine IL-18. Wrn helicase mutants also exhibited an increase in serum hydroxyproline and plasminogen activator inhibitor-1, markers of extracellular matrix remodeling of the vascular system and inflammation in aging. We also observed an abnormal increase in the ratio of very long chain to short chain lysophosphatidylcholines in the Wrn helicase mutants underlying a peroxisome perturbation in these mice. Remarkably, the Wrn mutant helicase protein was mislocalized to the endoplasmic reticulum and the peroxisomal fractions in liver tissues. Additional analyses with mouse embryonic fibroblasts indicated a severe defect of the autophagy flux in cells derived from Wrn helicase mutants compared to wild type and Wrn null animals. These results indicate that the deleterious effects of the helicase-deficient Wrn protein are mediated by the dysfunction of several cellular organelles.

Werner syndrome: clinical evaluation of two cases and a novel mutation

Werner syndrome (WS) is a premature aging disorder, inherited in an autosomal recessive pattern and caused by the mutation in the WRN gene. In this report we describe two male patients with negative family history who demonstrate characteristic findings of WS, with different mutations, including one novel mutation. The first case was a 47-year-old man who had been suffering from large, ischemic ulcers on both legs for 7 years. Physical examination revealed a thin and short man with severe wasting of all extremities. He had a high-pitched voice, hoarseness, a characteristic bird-like facies, bilateral cataracts, generalized osteoporosis, hypotrichosis, atrophic and poikilodermic skin, flexion contractures of hands, feet and knees, and soft tissue calcifications. Laboratory investigations revealed anemia, high erythrocyte sedimentation rate, low creatinine clearance, and high liver enzymes. Genetic analysis showed a homozygous novel 1bp-deletion in exon 19 of WRN, 2426/27delG, causing frameshift and protein truncation R809SfsX2, which has not been described before. The second case was a 23-year-old man who was referred for large callosities on both feet, present for 7 years. He complained of weakness, weight loss, wasting of muscles, and early graying of hair. The entire skin was thin, wrinkled and dry. Generalized hypotrichosis, scattered ephelid-like macules, sclerotic fingers, calcinosis cutis on ears, hyperpigmentation on elbows were the other alterations of skin. Skeletal survey revealed osteoporosis. Genetic analysis showed a homozygous known pathogenic splice site mutation c.3460-2A>G, causing skipping of Exon 30 in WRN.

The Drosophila orthologue of progeroid human WRN exonuclease, DmWRNexo, cleaves replication substrates but is inhibited by uracil or abasic sites : analysis of DmWRNexo activity in vitro

Werner syndrome (WS) is a rare late-onset premature ageing disease showing many of the phenotypes associated with normal ageing, and provides one of the best models for investigating cellular pathways that lead to normal ageing. WS is caused by mutation of WRN, which encodes a multifunctional DNA replication and repair helicase/exonuclease. To investigate the role of WRN protein's unique exonuclease domain, we have recently identified DmWRNexo, the fly orthologue of the exonuclease domain of human WRN. Here, we fully characterise DmWRNexo exonuclease activity in vitro, confirming 3'-5' polarity, demonstrating a requirement for Mg(2+), inhibition by ATP, and an ability to degrade both single-stranded DNA and duplex DNA substrates with 3' or 5' overhangs, or bubble structures, but with no activity on blunt ended DNA duplexes. We report a novel active site mutation that ablates enzyme activity. Lesional substrates containing uracil are partially cleaved by DmWRNexo, but the enzyme pauses on such substrates and is inhibited by abasic sites. These strong biochemical similarities to human WRN suggest that Drosophila can provide a valuable experimental system for analysing the importance of WRN exonuclease in cell and organismal ageing.

Werner syndrome: a changing pattern of clinical manifestations in Japan (1917~2008)

As ~75% of the Werner syndrome (WS) patients recognized between 1904 and 2008 all over the world are of Japanese origin, the most case reports and clinical studies on WS has been published in Japanese journals. Thus, the detailed English-written clinical review on the recent WS case reports has been warranted. Although WS has been characterized by a variety of clinical manifestations mimicking premature aging, the recent longevity and delayed age-associated manifestations observed both from Japanese WS and general population may suggest a common environmental effect on some gene(s) other than WRN and may give us a newer pathophysiological look at WS and also natural aging through the molecular dysfunction of WRN.

Small changes, big effects: chromatin goes aging

Aging is a complex trait and is influenced by multiple factors that are both intrinsic and extrinsic to the organism (Kirkwood et al. 2000; Knight 2000). Efforts to understanding the mechanisms that extend or shorten lifespan have been made since the early twentieth century. Aging is characteristically associated with a progressive decline in the overall fitness of the organism. Several studies have provided valuable information about the molecular events that accompany this process and include accumulation of nuclear and mitochondrial mutations, shortened and dysfunctional telomeres, oxidative damage of protein/DNA, senescence and apoptosis (Muller 2009). Clinical studies and work on model organisms have shown that there is an increased susceptibility to conditions such as neurological disorders, diabetes, cardiovascular diseases, degenerative syndromes and even cancers, with age (Arvanitakis et al. 2006; Lee and Kim 2006; Rodriguez and Fraga 2010).

Applying and testing the conveniently optimized enzyme mismatch cleavage method to clinical DNA diagnosis

Establishing a simple and effective mutation screening method is one of the most compelling problems with applying genetic diagnosis to clinical use. Because there is no reliable and inexpensive screening system, amplifying by PCR and performing direct sequencing of every coding exon is the gold standard strategy even today. However, this approach is expensive and time consuming, especially when gene size or sample number is large. Previously, we developed CEL nuclease mediated heteroduplex incision with polyacrylamide gel electrophoresis and silver staining (CHIPS) as an ideal simple mutation screening system constructed with only conventional apparatuses and commercially available reagents. In this study, we evaluated the utility of CHIPS technology for genetic diagnosis in clinical practice by applying this system to screening for the COL2A1, WRN and RPS6KA3 mutations in newly diagnosed patients with Stickler syndrome (autosomal dominant inheritance), Werner syndrome (autosomal recessive inheritance) and Coffin-Lowry syndrome (X-linked inheritance), respectively. In all three genes, CHIPS detected all DNA variations including disease causative mutations within a day. Direct sequencing of all coding exons of these genes confirmed 100% sensitivity and specificity. We demonstrate high sensitivity, high cost performance and reliability of this simple system, with compatibility to all inheritance modes. Because of its low technology, CHIPS is ready to use and potentially disseminate to any laboratories in the world.

The heat shock transcription factor Hsf1 is downregulated in DNA damage-associated senescence, contributing to the maintenance of senescence phenotype

Heat shock response (HSR) that protects cells from proteotoxic stresses is downregulated in aging, as well as upon replicative senescence of cells in culture. Here we demonstrate that HSR is suppressed in fibroblasts from the patients with segmental progerioid Werner Syndrome, which undergo premature senescence. Similar suppression of HSR was seen in normal fibroblasts, which underwent senescence in response to DNA damaging treatments. The major DNA-damage-induced signaling (DDS) pathways p53-p21 and p38-NF-kB-SASP contributed to the HSR suppression. The HSR suppression was associated with inhibition of both activity and transcription of the heat shock transcription factor Hsf1. This inhibition in large part resulted from the downregulation of SIRT1, which in turn was because of decrease in the expression of the translation regulator HuR. Importantly, we uncovered a positive feedback regulation, where suppression of Hsf1 further activates the p38-NF-κB-SASP pathway, which in turn promotes senescence. Overexpression of Hsf1 inhibited the p38-NFκB-SASP pathway and partially relieved senescence. Therefore, downregulation of Hsf1 plays an important role in the development or in the maintenance of DNA damage signaling-induced cell senescence.

The Werner syndrome gene product (WRN): a repressor of hypoxia-inducible factor-1 activity

Werner syndrome (WS) is a rare autosomal disease characterized by the premature onset of several age-associated pathologies. The protein defective in WS patients (WRN) is a helicase/exonuclease involved in DNA repair, replication, transcription and telomere maintenance. Hypoxia-inducible factor-1 (HIF-1) is a decisive element for the transcriptional regulation of genes essential for adaptation to low oxygen conditions. HIF-1 is also implicated in the molecular mechanisms of ageing. Here, we show that the cellular depletion of WRN protein (by siRNA targeting) leads to increased HIF-1 complex stabilization and activation. HIF-1 activation in the absence of WRN involves the generation of mitochondrial reactive oxygen species (mtROS) since SkQ1, a mitochondrial-targeted antioxidant, and stigmatellin, an inhibitor of mitochondrial complex III, blocked increased HIF-1 levels. Ascorbate, an essential co-factor involved in HIF-1 stability, was decreased in WRN-depleted cells. Interestingly, expression levels of GLUT1, a known dehydroascorbic acid transporter, were also decreased in WRN-depleted cells. Ascorbate supplementation of WRN-depleted cells led to a dose-dependent inhibition of HIF-1 activation. These results indicate that WRN protein regulates HIF-1 activation by affecting mitochondrial ROS production and intracellular ascorbate levels. This work provides a novel mechanistic link between HIF-1 activity and different age-associated pathologies.

Single nucleotide polymorphism WRN Leu1074Phe is associated with prostate cancer susceptibility in Chinese subjects

Deficiencies in the human DNA repair gene WRN are the cause of Werner syndrome, a rare autosomal recessive disorder characterized by premature aging and a predisposition to cancer. This study evaluated the association of WRN Leu1074Phe (rs1801195), a common missense single nucleotide polymorphism in WRN, with prostate cancer susceptibility in Chinese subjects. One hundred and forty-seven prostate cancer patients and 111 male cancer-free control subjects from 3 university hospitals in China were included. Blood samples were obtained from each subject, and the single nucleotide polymorphism WRN Leu1074Phe was genotyped by using a Snapshot assay. The results showed that WRN Leu1074Phe was associated with the risk of prostate cancer in Chinese men and that the TG/GG genotype displayed a decreased prevalence of prostate cancer compared with the TT genotype (OR＝0.58, 95%CI:0.35-0.97, p＝0.039). Through stratified analysis, more significant associations were revealed for the TG/GG genotype in the subgroup with diagnosis age ≤ 72 yr (OR＝0.27, 95%CI:0.12-0.61, p＝0.002) and in patients with localized diseases (OR＝0.36, 95%CI:0.19-0.70, p＝0.003). However, no statistically significant difference was found in the subgroup with age ＞72 yr or in patients with advanced diseases. We concluded that the genetic variant Leu1074Phe in the DNA repair gene WRN might play a role in the risk of prostate cancer in Chinese subjects.

The Werner's Syndrome RecQ helicase/exonuclease at the nexus of cancer and aging

Werner's Syndrome (WS) or adult-onset progeria is an autosomal recessive disorder of accelerated aging caused by mutations of the DNA RecQ helicase/exonuclease (WRN). WRN is an ATP-dependent helicase with 3' to 5' DNA exonuclease activity that regulates the replicative potential of dividing cells, and WRN loss-of-function mutations promote cellular senescence and neoplastic transformation. These molecular findings translate clinically into adult-onset progeria manifested by premature hair graying, dermal atrophy, cardiovascular disease, and cancer predilection along with a markedly reduced life expectancy. Recently, a patient with WS who developed pancreatic adenocarcinoma was identified in Honolulu suggesting a significant prevalence of loss-of-function WRN mutations in Hawaii's Japanese-American population. Based upon the indigenous Japanese WRN loss-of-function mutation heterozygote rate of 6 per 1,000, we speculate the possibility of approximately 1,200 heterozygotes in Hawaii. Our ongoing studies aim to evaluate Hawaii's true allelic prevalence of WRN loss-of-function mutations in the Japanese-American population, and the role of WRN silencing in sporadic cancers. In summary, WRN plays a nexus-like role in the complex interplay of cellular events that regulate aging, and analysis of WRN polymorphisms in Hawaii's population will generate novel insights to advance care for age-related pathologies.