RESUMEN
Werner syndrome (WS) is an autosomal recessive disease caused by loss of function of WRN. WS is a segmental progeroid disease and shows early onset or increased frequency of many characteristics of normal aging. WRN possesses helicase, annealing, strand exchange, and exonuclease activities and acts on a variety of DNA substrates, even complex replication and recombination intermediates. Here, we review the genetics, biochemistry, and probably physiological functions of the WRN protein. Although its precise role is unclear, evidence suggests WRN plays a role in pathways that respond to replication stress and maintain genome stability particularly in telomeric regions.
Asunto(s)
Replicación del ADN , Inestabilidad Genómica , Helicasa del Síndrome de Werner , Síndrome de Werner , Helicasa del Síndrome de Werner/metabolismo , Helicasa del Síndrome de Werner/genética , Humanos , Síndrome de Werner/genética , Síndrome de Werner/metabolismo , Animales , Telómero/metabolismo , Telómero/genéticaRESUMEN
James German's work to establish the natural history and cancer risk associated with Bloom syndrome (BS) has had a strong influence on the generation of scientists and clinicians working to understand other RECQ deficiencies and heritable cancer predisposition syndromes. I summarize work by us and others below, inspired by James German's precedents with BS, to understand and compare BS with the other heritable RECQ deficiency syndromes with a focus on Werner syndrome (WS). What we know, unanswered questions and new opportunities are discussed, as are potential ways to treat or modify WS-associated disease mechanisms and pathways.
Asunto(s)
Síndrome de Bloom , RecQ Helicasas , Síndrome de Werner , Humanos , RecQ Helicasas/genética , RecQ Helicasas/metabolismo , RecQ Helicasas/deficiencia , Síndrome de Bloom/genética , Síndrome de Werner/genética , Historia del Siglo XXRESUMEN
The underlying mechanisms of atherosclerosis, the second leading cause of death among Werner syndrome (WS) patients, are not fully understood. Here, we establish an in vitro co-culture system using macrophages (iMφs), vascular endothelial cells (iVECs), and vascular smooth muscle cells (iVSMCs) derived from induced pluripotent stem cells. In co-culture, WS-iMφs induces endothelial dysfunction in WS-iVECs and characteristics of the synthetic phenotype in WS-iVSMCs. Transcriptomics and open chromatin analysis reveal accelerated activation of type I interferon signaling and reduced chromatin accessibility of several transcriptional binding sites required for cellular homeostasis in WS-iMφs. Furthermore, the H3K9me3 levels show an inverse correlation with retrotransposable elements, and retrotransposable element-derived double-stranded RNA activates the DExH-box helicase 58 (DHX58)-dependent cytoplasmic RNA sensing pathway in WS-iMφs. Conversely, silencing type I interferon signaling in WS-iMφs rescues cell proliferation and suppresses cellular senescence and inflammation. These findings suggest that Mφ-specific inhibition of type I interferon signaling could be targeted to treat atherosclerosis in WS patients.
Asunto(s)
Aterosclerosis , Inflamación , Interferón Tipo I , Macrófagos , Retroelementos , Síndrome de Werner , Interferón Tipo I/metabolismo , Síndrome de Werner/genética , Síndrome de Werner/metabolismo , Humanos , Aterosclerosis/metabolismo , Aterosclerosis/inmunología , Aterosclerosis/genética , Aterosclerosis/patología , Macrófagos/metabolismo , Macrófagos/inmunología , Retroelementos/genética , Inflamación/metabolismo , Inflamación/patología , Inflamación/genética , Células Madre Pluripotentes Inducidas/metabolismo , Transducción de Señal , Técnicas de Cocultivo , Miocitos del Músculo Liso/metabolismo , Células Endoteliales/metabolismo , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patología , ARN Helicasas DEAD-box/metabolismo , ARN Helicasas DEAD-box/genética , Senescencia Celular , Proliferación CelularRESUMEN
AIMSWERNER SYNDROME IS A RARE PREMATURE AGEING AUTOSOMAL RECESSIVE DISORDER CAUSED BY PATHOGENIC VARIANTS IN THE WRN GENE. PEOPLE WITH WERNER SYNDROME MAY DEVELOP DIABETES MELLITUS. CHRONIC FOOT ULCERATION IS SEEN, WITH SOME CHARACTERISTICS OVERLAPPING WITH DIABETIC FOOT DISEASE. HOWEVER, THE CLINICAL COURSE OF THE ULCERATION IS ATYPICAL OF DIABETIC FOOT DISEASE. WE PRESENT FOUR SIBLINGS FROM AN IRISH TRAVELLER FAMILY WITH WERNER SYNDROME TO HIGHLIGHT THE COMPLEXITY OF THIS CONDITION. THE IRISH TRAVELLER POPULATION ARE AN INDIGENOUS, ENDOGAMOUS POPULATION IN WHICH CONSANGUINITY IS COMMON. AS A RESULT, RARE AUTOSOMAL RECESSIVE DISORDERS ARE PREVALENT AMONG THIS POPULATION: . METHODS: We describe our experience managing the complex foot disease seen in all four siblings. Foot complications present in the siblings include painful peripheral neuropathy, chronic foor ulceration, underlying osteomyelitis and acral melanoma. RESULTS: The cases are described individually, with a particular focus on the complex foot disease associated with the condition. CONCLUSIONS: Although the siblings attend a diabetic foot clinic, we suggest that the combination of clinical features seen in these cases is unique to Werner syndrome and warrants the title 'Werner Syndrome' (rather than 'Diabetic') foot.
Asunto(s)
Pie Diabético , Hermanos , Síndrome de Werner , Humanos , Síndrome de Werner/genética , Síndrome de Werner/complicaciones , Síndrome de Werner/diagnóstico , Masculino , Femenino , Persona de Mediana Edad , Adulto , Pie Diabético/diagnóstico , Irlanda , Melanoma/genética , Melanoma/diagnóstico , Melanoma/complicaciones , Osteomielitis/diagnóstico , Osteomielitis/genética , Osteomielitis/complicaciones , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/genética , Consanguinidad , Úlcera del Pie/genética , Úlcera del Pie/etiologíaRESUMEN
Werner syndrome (WS) is a progeroid disorder caused by mutations in a protein containing both a DNA exonuclease and DNA helicase domains. Previous studies indicated that males lacking the helicase domain of the Wrn protein orthologue exhibited hepatic transcriptomic and metabolic alterations. In this study, we used a label-free liquid chromatography-tandem mass spectrometry approach to uncover proteins abundance associated with specific biological processes that differed depending on the age (four or ten months) and/or the genotype (wild type or Wrn mutant) in the serum and liver of mice. Principal component analysis of the proteomic data from both serum and hepatic tissue revealed a sexual dimorphism regardless of the age and the genotype of the mice. Moreover, although all Wrn mutant mice exhibited fatty liver by the age of ten months, a significant age and genotype dependent enrichment of proteins involved in lipid and fatty acid metabolic processes were uncovered only in males. Also, a genotype dependent increase in serum oxidant detoxification processes was observed in the serum of Wrn mutant males. Despite these sexual differences, several aspects of the immune system were affected in both females and males. Finally, an increase of specific immunoglobulin molecules was common in the liver and serum of both older Wrn mutant females and males. Such results suggest that specific immunoglobulin variants maybe associated with fatty liver progression in WS.
Asunto(s)
Envejecimiento , Modelos Animales de Enfermedad , Hígado , Proteómica , Caracteres Sexuales , Helicasa del Síndrome de Werner , Síndrome de Werner , Animales , Masculino , Femenino , Síndrome de Werner/genética , Hígado/metabolismo , Ratones , Envejecimiento/inmunología , Helicasa del Síndrome de Werner/genética , Helicasa del Síndrome de Werner/metabolismoRESUMEN
Werner syndrome (WS) is a rare genetic disease in humans, caused by mutations in the WRN gene that encodes a protein containing helicase and exonuclease domains. WS is characterized by symptoms of accelerated aging in multiple tissues and organs, involving increased risk of cancer, heart failure, and metabolic dysfunction. These conditions ultimately lead to the premature mortality of patients with WS. In this study, using the null mutant flies (WRNexoΔ) for the gene WRNexo (CG7670), homologous to the exonuclease domain of WRN in humans, we examined how diets affect the lifespan, stress resistance, and sleep/wake patterns of a Drosophila model of WS. We observed that dietary restriction (DR), one of the most robust nongenetic interventions to extend lifespan in animal models, failed to extend the lifespan of WRNexoΔ mutant flies and even had a detrimental effect in females. Interestingly, the mean lifespan of WRNexoΔ mutant flies was not reduced on a protein-rich diet compared to that of wild-type (WT) flies. Compared to WT control flies, the mutant flies also exhibited altered responses to DR in their resistance to starvation and oxidative stress, as well as changes in sleep/wake patterns. These findings show that the WRN protein is necessary for mediating the effects of DR and suggest that the exonuclease domain of WRN plays an important role in metabolism in addition to its primary role in DNA-repair and genome stability.
Asunto(s)
Restricción Calórica , Modelos Animales de Enfermedad , Proteínas de Drosophila , Exonucleasas , Longevidad , Síndrome de Werner , Animales , Síndrome de Werner/genética , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Femenino , Masculino , Estrés Oxidativo , Drosophila melanogaster/genética , Mutación , Helicasa del Síndrome de Werner/genética , Drosophila , SueñoRESUMEN
Microsatellite instability (MSI) is a relatively common feature associated with multiple cancers, and Werner syndrome (WRN) ATP-dependent helicase has been recognized as a novel target for treating MSI cancers, such as colorectal cancer. A small-molecule inhibitor targeting WRN would be a promising strategy for treating colorectal cancer with high MSI expression. In this study, we employed a computer-assisted drug discovery strategy to screen over 30,000 natural product molecules. By using a combination of docking, ligand efficiency, Molecular Mechanics/Generalized Born Surface Area (MM/GBSA), and thermodynamic integration (TI) calculations, we identified MOL008980, MOL010740, MOL011832, T4743, TN1166, and TNP-002173 as potential WRN inhibitors. Subsequent molecular dynamics simulation revealed that these screened natural products possessed better binding dynamic characteristics than ATP substrate and were capable of inhibiting the dynamic process of WRN, making them potential strong ATP competitive inhibitors. In conclusion, our computational approach revealed potential WRN inhibitors from a natural product database, providing a theoretical basis for future research.
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Productos Biológicos , Neoplasias Colorrectales , Síndrome de Werner , Humanos , Helicasa del Síndrome de Werner/metabolismo , Adenosina Trifosfato , Productos Biológicos/farmacologíaRESUMEN
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-ß-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.
Asunto(s)
Síndrome de Werner , Animales , Ratones , Síndrome de Werner/genética , Daño del ADN , Telómero , Senescencia Celular , ADN Helicasas/genéticaRESUMEN
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.
Asunto(s)
Resistencia a la Insulina , Síndrome de Werner , Femenino , Humanos , Síndrome de Werner/diagnóstico , Síndrome de Werner/genética , Helicasa del Síndrome de Werner/genética , Resistencia a la Insulina/genética , Mutación , Pruebas GenéticasRESUMEN
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.
Asunto(s)
Diabetes Mellitus , Neoplasias Meníngeas , Síndrome de Werner , Masculino , Humanos , Adulto , Síndrome de Werner/complicaciones , Síndrome de Werner/genética , Síndrome de Werner/diagnóstico , Mutación , ADN , Helicasa del Síndrome de Werner/genéticaRESUMEN
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.
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Diabetes Mellitus Tipo 1 , Diabetes Mellitus Tipo 2 , Osteoporosis , Síndrome de Werner , Masculino , Niño , Adolescente , Humanos , Adulto , Adulto Joven , Síndrome de Werner/diagnóstico , Síndrome de Werner/genética , ADN Helicasas/genética , Diabetes Mellitus Tipo 2/genéticaRESUMEN
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.
Asunto(s)
Síndrome de Cockayne , Progeria , Piridonas , Pirimidinonas , Síndrome de Werner , Humanos , Síndrome de Werner/tratamiento farmacológico , Síndrome de Werner/genética , Síndrome de Cockayne/tratamiento farmacológico , Síndrome de Cockayne/genética , Empalme Alternativo/genética , Senoterapéuticos , Progeria/tratamiento farmacológico , Progeria/genética , Factores de Empalme de ARNRESUMEN
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.
Asunto(s)
Síndrome de Werner , Humanos , Masculino , Femenino , Síndrome de Werner/diagnóstico , Síndrome de Werner/genética , Estudios Retrospectivos , Caracteres Sexuales , Helicasa del Síndrome de Werner/genética , MutaciónAsunto(s)
Enfermedad de Hashimoto , Paniculitis , Síndrome de Sjögren , Síndrome de Werner , Humanos , Enfermedad de Hashimoto/complicaciones , Enfermedad de Hashimoto/diagnóstico , Paniculitis/complicaciones , Síndrome de Sjögren/complicaciones , Síndrome de Sjögren/diagnóstico , Síndrome de Werner/complicaciones , Síndrome de Werner/diagnóstico , Masculino , AdultoRESUMEN
BACKGROUND: Sclerosing epithelioid fibrosarcoma is an aggressive sarcoma subtype with poor prognosis and limited response to conventional chemotherapy regimens. Diagnosis can be difficult owing to its variable presentation, and cases of sclerosing epithelioid fibrosarcoma are rare. Sclerosing epithelioid fibrosarcoma typically affects middle-aged individuals, with studies inconsistently citing gender predominance. Sclerosing epithelioid fibrosarcoma typically arises from the bones and soft tissues and often has local recurrence after resection and late metastases. Immunohistochemical staining typically is positive for mucin-4. Werner syndrome is due to an autosomal recessive mutation in the WRN gene and predisposes patients to malignancy. CASE PRESENTATION: A 37-year-old Caucasian female presented to the emergency department with 4 months of dyspnea and back pain. She had been treated for pneumonia but had persistent symptoms. A chest, abdomen, and pelvis computed tomography showed near-complete right upper lobe collapse and consolidation, mediastinal lymphadenopathy, lytic spinal lesions, and a single 15-mm hypodense liver nodule. The patient underwent a transthoracic right upper lobe biopsy, bronchoscopy, endobronchial ultrasound with transbronchial lymph node sampling, and bronchoalveolar lavage of the right upper lobe. The bronchoalveolar lavage cytology was positive for malignant cells compatible with poorly differentiated non-small cell carcinoma; however, the cell block materials were insufficient to run immunostains for further investigation of the bronchoalveolar lavage results. Consequently, the patient also underwent a liver biopsy of the liver nodule, which later confirmed a diagnosis of sclerosing epithelioid fibrosarcoma. Next-generation sequencing revealed a variant of unknown significance in the WRN gene. She was subsequently started on doxorubicin. CONCLUSION: Sclerosing epithelioid fibrosarcoma is a very rare entity, only cited approximately 100 times in literature to date. Physicians should be aware of this disease entity and consider it in their differential diagnosis. Though pulmonary involvement has been described in the context of sclerosing epithelioid fibrosarcoma, this malignancy may affect many organ systems, warranting extensive investigation. Through our diagnostic workup, we suggest a possible link between sclerosing epithelioid fibrosarcoma and the WRN gene. Further study is needed to advance our understanding of sclerosing epithelioid fibrosarcoma and its clinical associations as it is an exceedingly rare diagnosis.
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Fibrosarcoma , Fracturas Espontáneas , Traumatismos del Cuello , Sarcoma , Fracturas de la Columna Vertebral , Síndrome de Werner , Persona de Mediana Edad , Humanos , Femenino , Adulto , Fibrosarcoma/complicaciones , Fibrosarcoma/diagnóstico , Fibrosarcoma/genética , Tomografía Computarizada por Rayos X , Disnea , Helicasa del Síndrome de WernerRESUMEN
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.
Asunto(s)
Resistencia a la Insulina , Insulinas , Lipodistrofia , Síndrome de Werner , Animales , Humanos , Síndrome de Werner/genética , Adipogénesis/genética , Caenorhabditis elegans , Senescencia Celular/genética , Grasa Subcutánea/metabolismo , Inflamación , Sirolimus , MamíferosRESUMEN
The G-rich DNA, such as telomere, tends to form G-quadruplex (G4) structure, which slows down the replication fork progression, induces replication stress, and becomes the chromosome fragile sites. Here we described a molecular strategy that cells developed to overcome the DNA replication stress via DNA helicase regulation. The p53N236S (p53S) mutation has been found in the Werner syndrome mouse embryo fibroblast (MEFs) escaped from senescence, could be the driving force for cell escaping senescence. We revealed that the p53S could transcriptionally up-regulate DNA helicases expression, including Wrn, Blm, Timeless, Ddx, Mcm, Gins, Fanc, as well as telomere specific proteins Terf1, Pot1, through which p53S promoted the unwinding of G4 structures, and protected the cells from DNA replication stress induced by G4 stabilizer. By modified iPOND (isolation of proteins on nascent DNA) assay and telomere assay, we demonstrated that the p53S could promote the recruitment of those helicases to the DNA replication forks, facilitated the maintenance of telomere, and prevent the telomere dysfunction induced by G4 stabilizer. Interestingly, we did not observe the function of promoting G4 resolving and facilitating telomere lengthening in the cells with Li-Fraumeni Syndrome mutation-p53R172H (p53H), which suggests that this is the specific gain of function for p53S. Together our data suggest that the p53S could gain the new function of releasing the replication stress via regulating the helicase function and G4 structure, which benefits telomere lengthening. This strategy could be applied to the treatment of diseases caused by telomere replication stress.
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Replicación del ADN , Síndrome de Werner , Animales , Ratones , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismo , Helicasa del Síndrome de Werner/genética , ADN Helicasas/genética , ADN Helicasas/metabolismo , ADN/genética , Telómero/genética , Telómero/metabolismo , RecQ Helicasas/genética , RecQ Helicasas/metabolismoRESUMEN
Werner syndrome protein (WRN) is a multifunctional enzyme with helicase, ATPase, and exonuclease activities that are necessary for numerous DNA-related transactions in the human cell. Recent studies identified WRN as a synthetic lethal target in cancers characterized by genomic microsatellite instability resulting from defects in DNA mismatch repair pathways. WRN's helicase activity is essential for the viability of these high microsatellite instability (MSI-H) cancers and thus presents a therapeutic opportunity. To this end, we developed a multiplexed high-throughput screening assay that monitors exonuclease, ATPase, and helicase activities of full-length WRN. This screening campaign led to the discovery of 2-sulfonyl/sulfonamide pyrimidine derivatives as novel covalent inhibitors of WRN helicase activity. The compounds are specific for WRN versus other human RecQ family members and show competitive behavior with ATP. Examination of these novel chemical probes established the sulfonamide NH group as a key driver of compound potency. One of the leading compounds, H3B-960, showed consistent activities in a range of assays (IC50 = 22 nM, KD = 40 nM, KI = 32 nM), and the most potent compound identified, H3B-968, has inhibitory activity IC50 â¼ 10 nM. These kinetic properties trend toward other known covalent druglike molecules. Our work provides a new avenue for screening WRN for inhibitors that may be adaptable to different therapeutic modalities such as targeted protein degradation, as well as a proof of concept for the inhibition of WRN helicase activity by covalent molecules.
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Neoplasias , Síndrome de Werner , Humanos , Exodesoxirribonucleasas/genética , RecQ Helicasas/genética , RecQ Helicasas/metabolismo , Ensayos Analíticos de Alto Rendimiento , Inestabilidad de Microsatélites , Helicasa del Síndrome de Werner/metabolismoRESUMEN
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.