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1.
Nat Commun ; 11(1): 4766, 2020 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-32958778

RESUMO

Germline telomere maintenance defects are associated with an increased incidence of inflammatory diseases in humans, yet whether and how telomere dysfunction causes inflammation are not known. Here, we show that telomere dysfunction drives pATM/c-ABL-mediated activation of the YAP1 transcription factor, up-regulating the major pro-inflammatory factor, pro-IL-18. The colonic microbiome stimulates cytosolic receptors activating caspase-1 which cleaves pro-IL-18 into mature IL-18, leading to recruitment of interferon (IFN)-γ-secreting T cells and intestinal inflammation. Correspondingly, patients with germline telomere maintenance defects exhibit DNA damage (γH2AX) signaling together with elevated YAP1 and IL-18 expression. In mice with telomere dysfunction, telomerase reactivation in the intestinal epithelium or pharmacological inhibition of ATM, YAP1, or caspase-1 as well as antibiotic treatment, dramatically reduces IL-18 and intestinal inflammation. Thus, telomere dysfunction-induced activation of the ATM-YAP1-pro-IL-18 pathway in epithelium is a key instigator of tissue inflammation.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas de Ciclo Celular/metabolismo , Inflamação/patologia , Telômero/patologia , Proteínas Adaptadoras de Transdução de Sinal/antagonistas & inibidores , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Antibacterianos/uso terapêutico , Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Caspase 1/metabolismo , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/genética , Criança , Colo/metabolismo , Colo/microbiologia , Colo/patologia , Gastroenteropatias/patologia , Microbioma Gastrointestinal/efeitos dos fármacos , Microbioma Gastrointestinal/fisiologia , Humanos , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Inflamação/microbiologia , Interleucina-18/genética , Interleucina-18/metabolismo , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Camundongos , Camundongos Mutantes , Fosforilação , Precursores de Proteínas/genética , Precursores de Proteínas/metabolismo , Transdução de Sinais , Telomerase/genética , Telomerase/metabolismo
2.
Hum Genet ; 139(12): 1531-1539, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32533363

RESUMO

The fragile X premutation is defined by the expansion of the CGG trinucleotide repeat at the 5' UTR of the FMR1 gene to between 55 and 200 repeats, while repeat tracks longer than 200 are defined as full mutations. Men carrying a premutation are at increased risk for fragile X-associated tremor/ataxia syndrome (FXTAS); those with > 200 repeats have fragile X syndrome, a common genetic form of intellectual disabilities. In our study, we tested the hypothesis that men carrying a fragile X premutation or full mutation are "biologically older", as suggested by the associated age-related disorder in the presence of the fragile X premutation or the altered cellular pathology that affects both the fragile X premutation and full mutation carriers. Thus, we predicted that both groups would have shorter telomeres than men carrying the normal size repeat allele. Using linear regression models, we found that, on average, premutation carriers had shorter telomeres compared with non-carriers (n = 69 vs n = 36; p = 0.02) and that there was no difference in telomere length between full mutation carriers and non-carriers (n = 37 vs n = 29; p > 0.10). Among premutation carriers only, we also asked whether telomere length was shorter among men with vs without symptoms of FXTAS (n = 28 vs n = 38 and n = 27 vs n = 41, depending on criteria) and found no evidence for a difference (p > 0.10). Previous studies have shown that the premutation is transcribed whereas the full mutation is not, and the expanded repeat track in FMR1 transcript is thought to lead to the risk for premutation-associated disorders. Thus, our data suggest that the observed premutation-only telomere shortening may be a consequence of the toxic effect of the premutation transcript and suggest that premutation carriers are "biologically older" than men carrying the normal size allele in the same age group.


Assuntos
Ataxia/genética , Proteína do X Frágil de Retardo Mental/genética , Síndrome do Cromossomo X Frágil/genética , Telômero/genética , Tremor/genética , Regiões 5' não Traduzidas/genética , Adulto , Idoso , Alelos , Ataxia/patologia , Síndrome do Cromossomo X Frágil/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Mutação/genética , Telômero/patologia , Telômero/ultraestrutura , Homeostase do Telômero/genética , Tremor/patologia , Expansão das Repetições de Trinucleotídeos/genética , Adulto Jovem
3.
Oxid Med Cell Longev ; 2020: 9256107, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32215181

RESUMO

Cellular aging markers, including telomere length and mitochondrial function, as well as oxidative stress and inflammation markers influence each other and form a complex network, which is affected in diabetes. However, it remains unknown whether these markers could independently predict future diabetes after adjustment for their mutual effects. We conducted a 3-year longitudinal study in a Chinese cohort that comprised 108 nondiabetic individuals at baseline. The 2-hour 75 g oral glucose tolerance tests were performed at baseline and at 3-year follow-up. At baseline, leukocyte telomere length (LTL) and mitochondrial DNA copy number (mtDNAcn) in leukocytes were determined using the polymerase chain reaction method. Tumor necrosis factor (TNF-α), interleukin-6, 8-hydroxy-2-deoxyguanosine levels, and superoxide dismutase (SOD) activity were measured by the enzyme-linked immunosorbent assay. Participants who developed diabetes at the 3-year follow-up (n = 28) had shorter LTL and higher levels of TNF-α and SOD activity at baseline. Baseline LTL was found to be independently associated with the development of diabetes at the 3-year follow-up after the adjustment for mtDNAcn, markers of oxidative stress and inflammation, and conventional diabetes risk factors. Our findings suggest that LTL is an independent predictor for 3-year diabetes risk, which might inform timely prevention and treatment of diabetes. Telomere shortening might be involved in the pathogenesis of diabetes independently of conventional diabetes risk factors, mtDNAcn, or oxidative stress and inflammation pathways.


Assuntos
Diabetes Mellitus/sangue , Leucócitos/patologia , Encurtamento do Telômero , Telômero/patologia , Grupo com Ancestrais do Continente Asiático , Biomarcadores/sangue , Senescência Celular , DNA Mitocondrial/sangue , Diabetes Mellitus/epidemiologia , Feminino , Voluntários Saudáveis , Humanos , Inflamação , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Estresse Oxidativo , Risco
4.
J Cancer Res Clin Oncol ; 146(2): 381-389, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31960186

RESUMO

PURPOSE: To evaluate the prevalence of two recurrent somatic mutations (-124 C>T and -146 C>T) within the promoter of the gene encoding telomerase reverse transcriptase (TERT) as well as their relationship with TERT level, telomeres length, and outcome in patients with head and neck squamous cell carcinomas (HNSCCs). METHODS: We evaluate the prevalence of TERT promoter mutations, TERT levels, and telomere length in paired cancer tissue and adjacent mucosa (AM) in a series of HNSCCs. RESULTS: Cancer tissue and AM specimens from 105 patients were analyzed. Telomere length and TERT mRNA levels were estimated using real-time polymerase chain reaction. TERT promoter mutations were assessed using Sanger sequencing. Out of 105 cases, 101 were considered suitable for the analysis. TERT promoter harbored mutations in 12 tumors (11.9%), with -124 C>T and -146 C>T accounting for 83.3% and 16.7% of the alterations, respectively. No mutations were detected in AM samples. The prevalence of TERT promoter mutations was significantly higher in oral cavity SCCs (10 out of 27 tumors; 37%), and telomere length in AM was shorter in patients with tumors carrying TERT promoter mutations than in patients with unmutated TERT promoter cancers (p = 0.023). TERT levels in tumor did not significantly differ according to the mutational status of TERT promoter. No significant association was found between TERT promoter status and overall survival. CONCLUSION: TERT promoter mutations are most likely a late event in tumor development, occurring in a context of critically short telomeres, mostly in patients with oral cavity SCC. TERT levels, but not TERT promoter mutational status impact clinical outcome.


Assuntos
Neoplasias de Cabeça e Pescoço/genética , Mutação , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Telomerase/genética , Telômero/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Neoplasias de Cabeça e Pescoço/metabolismo , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Regiões Promotoras Genéticas , Estudos Prospectivos , Carcinoma de Células Escamosas de Cabeça e Pescoço/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Análise de Sobrevida , Telomerase/metabolismo , Telômero/genética , Telômero/patologia
5.
Biol Psychol ; 150: 107809, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31734351

RESUMO

Although maternal postpartum depressive symptoms (PDS) are associated with child behavior problems, the underlying biological mechanisms are poorly understood. Thus, the current study focused on 193 healthy mother-child dyads and investigated child cortisol and telomere length as potential mediating factors. At 3 and 6 months postpartum, mothers reported on PDS. At age 6, children provided saliva and buccal swab samples. At age 10, mothers and children reported on child behavior problems. Structural equation modelling revealed (a) no association between PDS and child behavior problems and thus no possibility of mediation, but that (b) lower cortisol forecast more child-reported internalizing problems, and (c) shorter telomere length predicted more child-reported internalizing and externalizing problems. These findings raise mediational questions about the determinants of these biomarkers.


Assuntos
Transtornos do Comportamento Infantil/metabolismo , Depressão Pós-Parto/psicologia , Hidrocortisona/análise , Mães/psicologia , Telômero/patologia , Adulto , Criança , Transtornos do Comportamento Infantil/psicologia , Mecanismos de Defesa , Feminino , Humanos , Análise de Classes Latentes , Masculino , Período Pós-Parto/psicologia , Comportamento Problema/psicologia , Saliva/química
6.
J Gerontol A Biol Sci Med Sci ; 75(2): 230-235, 2020 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-30388200

RESUMO

Telomeres progressively shorten with age, and it has been proposed that critically short and dysfunctional telomeres contribute to aging and aging-associated diseases in humans. For many years it was thought that telomere erosion was strictly a consequence of the "end replication problem," or the inability of replicative polymerases to completely duplicate linear DNA ends. It is becoming increasingly evident, however, that telomere shortening of cultured human cells is also caused because of other replication defects in telomeric repeats, those that cause fragile telomeres and other aberrant telomeric structures that can be detected on metaphase chromosomes. Whether these replication defects contribute to telomere erosion also in human tissues is currently unknown. By analyzing peripheral blood mononuclear cells from a total of 35 healthy subjects ranging in age from 23 to 101 years, we demonstrated that telomeres increasingly display aberrant structures with advancing donor age. Although the percentages of fragile telomeres increased only until adulthood, the percentages of chromosomes displaying sister telomere loss and sister telomere chromatid fusions increased consistently throughout the entire human life span. Our data, therefore, suggest that telomeric replication defects other than the end replication problem contribute to aging-associated telomere erosion in humans.


Assuntos
Envelhecimento/patologia , Telômero/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Voluntários Saudáveis , Humanos , Hibridização in Situ Fluorescente , Leucócitos Mononucleares , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Encurtamento do Telômero
7.
Int J Mol Sci ; 21(1)2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31877678

RESUMO

In this study, we describe the identification of a novel splice variant of TERF1/PIN2, one of the main components of the telomeric shelterin complex. This new splice variant is identical to TERF1, apart from a 30 amino acid internal insertion near to the C-terminus of TERF1. Based on genome comparison analyses and RNA expression data, we show that this splice variant is conserved among hominidae but absent from all other species. RNA expression and histological analyses show specific expression in human spermatogonial and hematopoietic stem cells (HSCs), while all other analyzed tissues lack the expression of this TERF1-isoform, hence the name TERF1-tsi (TERF1-tissue-specific-isoform). In addition, we could not detect any expression in primary human cells and established cancer cell lines. Immunohistochemistry results involving two new rabbit polyclonal antibodies, generated against TERF1-tsi specific peptides, indicate nuclear localization of TERF1-tsi in a subset of spermatogonial stem cells. In line with this observation, immunofluorescence analyzes in various cell lines consistently revealed that ectopic TERF1-tsi localizes to the cell nucleus, mainly but not exclusively at telomeres. In a first attempt to evaluate the impact of TERF1-tsi in the testis, we have tested its expression in normal testis samples versus matched tumor samples from the same patients. Both RT-PCR and IHC show a specific downregulation of TERF1-tsi in tumor samples while the expression of TERF1 and PIN2 remains unchanged.


Assuntos
Regulação para Baixo , Seminoma/genética , Proteínas de Ligação a Telômeros/genética , Neoplasias Testiculares/genética , Animais , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Humanos , Masculino , Camundongos , Isoformas de Proteínas/análise , Isoformas de Proteínas/genética , Seminoma/patologia , Telômero/genética , Telômero/patologia , Proteínas de Ligação a Telômeros/análise , Neoplasias Testiculares/patologia , Testículo/metabolismo , Testículo/patologia
8.
Aging (Albany NY) ; 11(21): 9893-9900, 2019 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-31707361

RESUMO

This study aimed to dissect the direct effect of smoking and its indirect effect through body mass index (BMI) on leukocyte telomere length (LTL) and to distinguish the mediation and suppression effects of BMI. The study cohort included 1,037 adults (729 Whites and 308 African Americans; 42.1% males; mean age: 40.3 years) with LTL measurements by Southern blotting. General third variable models were used to distinguish the mediation and suppression effects of BMI on the smoking-LTL association. After adjusting for age, race, sex and alcohol drinking, the total effect of smoking on LTL was significant (standardized regression coefficient, ß= -0.061, p=0.034) without BMI included in the model. With additional adjustment for BMI, the indirect effect of smoking on LTL through BMI was estimated at ß= 0.011 (p=0.023), and the direct effect of smoking on LTL was strengthened to ß= -0.072 (p=0.012). The results were similar when pack-years of smoking was used. The effect parameters did not differ significantly between race and sex groups. These results suggest that BMI has a suppression effect, not a mediation effect, on the smoking-LTL association, which potentially contributes to previous inconsistencies in the effect of smoking on LTL.


Assuntos
Peso Corporal/genética , Peso Corporal/fisiologia , Fumar Cigarros/efeitos adversos , Fumar Cigarros/genética , Telômero/patologia , Adulto , Afro-Americanos/genética , Índice de Massa Corporal , Estudos de Coortes , Grupo com Ancestrais do Continente Europeu/genética , Feminino , Humanos , Leucócitos/patologia , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Fatores Sexuais , Homeostase do Telômero/genética , Homeostase do Telômero/fisiologia , Encurtamento do Telômero/genética , Encurtamento do Telômero/fisiologia
9.
Medicina (Kaunas) ; 55(11)2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31752241

RESUMO

Background and Objectives: ZBTB48 is a telomere-associated factor that has been renamed as telomeric zinc finger-associated protein (TZAP). It binds preferentially to long telomeres, competing with telomeric repeat factors 1 and 2. Materials and Methods: We analyzed the TZAP mutation in 128 breast carcinomas (BCs). In addition, its association with telomere length was investigated. Results: The TZAP mutation (c.1272 G > A, L424L) was found in 7.8% (10/128) of the BCs and was associated with the N0 stage. BCs with the TZAP mutation had longer telomeres than those without this mutation. Survival analysis showed that the TZAP mutation resulted in poorer overall survival. Conclusions: These results suggest that the TZAP mutation is a possible prognostic marker in BC.


Assuntos
Neoplasias da Mama/complicações , Proteínas de Ligação a DNA/genética , Mutação/genética , Fatores de Transcrição/genética , Adulto , Neoplasias da Mama/genética , Distribuição de Qui-Quadrado , Feminino , Humanos , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase/métodos , Prognóstico , Estatísticas não Paramétricas , Telômero/genética , Telômero/patologia
10.
EMBO J ; 38(23): e101982, 2019 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-31633821

RESUMO

Cellular senescence has been shown to contribute to skin ageing. However, the role of melanocytes in the process is understudied. Our data show that melanocytes are the only epidermal cell type to express the senescence marker p16INK4A during human skin ageing. Aged melanocytes also display additional markers of senescence such as reduced HMGB1 and dysfunctional telomeres, without detectable telomere shortening. Additionally, senescent melanocyte SASP induces telomere dysfunction in paracrine manner and limits proliferation of surrounding cells via activation of CXCR3-dependent mitochondrial ROS. Finally, senescent melanocytes impair basal keratinocyte proliferation and contribute to epidermal atrophy in vitro using 3D human epidermal equivalents. Crucially, clearance of senescent melanocytes using the senolytic drug ABT737 or treatment with mitochondria-targeted antioxidant MitoQ suppressed this effect. In conclusion, our study provides proof-of-concept evidence that senescent melanocytes affect keratinocyte function and act as drivers of human skin ageing.


Assuntos
Envelhecimento/patologia , Atrofia/patologia , Senescência Celular , Melanócitos/patologia , Pele/patologia , Telômero/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/efeitos dos fármacos , Atrofia/induzido quimicamente , Células Cultivadas , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Epiderme/efeitos dos fármacos , Epiderme/patologia , Feminino , Humanos , Masculino , Melanócitos/metabolismo , Pessoa de Meia-Idade , Comunicação Parácrina , Espécies Reativas de Oxigênio/metabolismo , Receptores CXCR4/metabolismo , Pele/metabolismo , Telômero/metabolismo , Adulto Jovem
11.
Ann Neurol ; 86(5): 671-682, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31486104

RESUMO

OBJECTIVE: To assess whether biological aging as measured by leukocyte telomere length (LTL) is associated with clinical disability and brain volume loss in multiple sclerosis (MS). METHODS: Adults with MS/clinically isolated syndrome in the University of California, San Francisco EPIC cohort study were included. LTL was measured on DNA samples by quantitative polymerase chain reaction and expressed as telomere to somatic DNA (T/S) ratio. Expanded Disability Status Scale (EDSS) and 3-dimensional T1-weighted brain magnetic resonance imaging were performed at baseline and follow-up. Associations of baseline LTL with cross-sectional and longitudinal outcomes were assessed using simple and mixed effects linear regression models. A subset (n = 46) had LTL measured over time, and we assessed the association of LTL change with EDSS change with mixed effects models. RESULTS: Included were 356 women and 160 men (mean age = 43 years, median disease duration = 6 years, median EDSS = 1.5 [range = 0-7], mean T/S ratio = 0.97 [standard deviation = 0.18]). In baseline analyses adjusted for age, disease duration, and sex, for every 0.2 lower LTL, EDSS was 0.27 higher (95% confidence interval [CI] = 0.13-0.42, p < 0.001) and brain volume was 7.4mm3 lower (95% CI = 0.10-14.7, p = 0.047). In longitudinal adjusted analyses, those with lower baseline LTL had higher EDSS and lower brain volumes over time. In adjusted analysis of the subset, LTL change was associated with EDSS change over 10 years; for every 0.2 LTL decrease, EDSS was 0.34 higher (95% CI = 0.08-0.61, p = 0.012). INTERPRETATION: Shorter telomere length was associated with disability independent of chronological age, suggesting that biological aging may contribute to neurological injury in MS. Targeting aging-related mechanisms is a potential therapeutic strategy against MS progression. ANN NEUROL 2019;86:671-682.


Assuntos
Esclerose Múltipla , Telômero/metabolismo , Adulto , Envelhecimento/fisiologia , Senescência Celular/fisiologia , Estudos de Coortes , Estudos Transversais , Avaliação da Deficiência , Progressão da Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/metabolismo , Esclerose Múltipla/patologia , Telômero/patologia , Homeostase do Telômero/fisiologia
12.
JAMA Netw Open ; 2(9): e199687, 2019 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-31553468

RESUMO

Importance: Telomere length is associated with the development of age-related diseases and structural differences in multiple brain regions. It remains unclear, however, whether change in telomere length is linked to brain structure change, and to what extent telomere length can be influenced through mental training. Objectives: To assess the dynamic associations between leukocyte telomere length (LTL) and cortical thickness (CT), and to determine whether LTL is affected by a longitudinal contemplative mental training intervention. Design, Setting, and Participants: An open-label efficacy trial of three 3-month mental training modules with healthy, meditation-naive adults was conducted. Data on LTL and CT were collected 4 times over 9 months between April 22, 2013, and March 31, 2015, as part of the ReSource Project. Data analysis was performed between September 23, 2016, and June 21, 2019. Of 1582 eligible individuals, 943 declined to participate; 362 were randomly selected for participation and assigned to training or retest control cohorts, with demographic characteristics matched. The retest control cohorts underwent all testing but no training. Intention-to-treat analysis was performed. Interventions: Training cohort participants completed 3 modules cultivating interoception and attention (Presence), compassion (Affect), or perspective taking (Perspective). Main Outcomes and Measures: Change in LTL and CT. Results: Of the 362 individuals randomized, 30 participants dropped out before study initiation (initial sample, 332). Data were available for analysis of the training intervention in 298 participants (n = 222 training; n = 76 retest control) (175 women [58.7%]; mean [SD] age, 40.5 [9.3] years). The training modules had no effect on LTL. In 699 observations from all 298 participants, mean estimated changes in the relative ratios of telomere repeat copy number to single-copy gene (T/S) were for no training, 0.004 (95% CI, -0.010 to 0.018); Presence, -0.007 (95% CI, -0.025 to 0.011); Affect, -0.005 (95% CI, -0.019 to 0.010); and Perspective, -0.001 (95% CI, -0.017 to 0.016). Cortical thickness change data were analyzed in 167 observations from 67 retest control participants (37 women [55.2%], mean [SD] age, 39.6 [9.0] years). In this retest control cohort subsample, naturally occurring LTL change was related to CT change in the left precuneus extending to the posterior cingulate cortex (mean t161 = 3.22; P < .001; r = 0.246). At the individual participant level, leukocyte telomere shortening as well as lengthening were observed. Leukocyte telomere shortening was related to cortical thinning (t77 = 2.38; P = .01; r = 0.262), and leukocyte telomere lengthening was related to cortical thickening (t77 = 2.42; P = .009; r = 0.266). All analyses controlled for age, sex, and body mass index. Conclusions and Relevance: The findings of this trial indicate an association between short-term change in LTL and concomitant change in plasticity of the left precuneus extending to the posterior cingulate cortex. This result contributes to the evidence that LTL changes more dynamically on the individual level than previously thought. Further studies are needed to determine potential long-term implications of such change in relation to cellular aging and the development of neurodegenerative disorders. No effect of contemplative mental training was noted in what may be, to date, the longest intervention with healthy adults. Trial Registration: ClinicalTrials.gov identifier: NCT01833104.


Assuntos
Envelhecimento/fisiologia , Córtex Cerebral/fisiologia , Cognição/fisiologia , Compreensão/fisiologia , Interocepção/fisiologia , Leucócitos/metabolismo , Saúde Mental , Telômero/fisiologia , Envelhecimento/psicologia , Córtex Cerebral/patologia , Feminino , Humanos , Leucócitos/patologia , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Telômero/patologia
13.
Expert Rev Hematol ; 12(12): 1037-1052, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31478401

RESUMO

Introduction: Telomere biology disorders (TBDs) encompass a group of illnesses caused by germline mutations in genes regulating telomere maintenance, resulting in very short telomeres. Possible TBD manifestations range from complex multisystem disorders with onset in childhood such as dyskeratosis congenita (DC), Hoyeraal-Hreidarsson syndrome, Revesz syndrome and Coats plus to adults presenting with one or two DC-related features.Areas covered: The discovery of multiple genetic causes and inheritance patterns has led to the recognition of a spectrum of clinical features affecting multiple organ systems. Patients with DC and associated TBDs are at high risk of bone marrow failure, cancer, liver and pulmonary disease. Recently, vascular diseases, including pulmonary arteriovenous malformations and gastrointestinal telangiectasias, have been recognized as additional manifestations. Diagnostics include detection of very short leukocyte telomeres and germline genetic testing. Hematopoietic cell transplantation and lung transplantation are the only current therapeutic modalities but are complicated by numerous comorbidities. This review summarizes the pathophysiology underlying TBDs, associated clinical features, management recommendations and therapeutic options.Expert opinion: Understanding TBDs as complex, multisystem disorders with a heterogenous genetic background and diverse phenotypes, highlights the importance of clinical surveillance and the urgent need to develop new therapeutic strategies to improve health outcomes.


Assuntos
Disceratose Congênita , Mutação em Linhagem Germinativa , Telômero , Disceratose Congênita/diagnóstico , Disceratose Congênita/genética , Disceratose Congênita/metabolismo , Disceratose Congênita/patologia , Humanos , Telômero/genética , Telômero/metabolismo , Telômero/patologia
14.
Proc Natl Acad Sci U S A ; 116(38): 18983-18993, 2019 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-31481614

RESUMO

Telomerase is an enzymatic ribonucleoprotein complex that acts as a reverse transcriptase in the elongation of telomeres. Telomerase activity is well documented in embryonic stem cells and the vast majority of tumor cells, but its role in somatic cells remains to be understood. Here, we report an unexpected function of telomerase during cellular senescence and tumorigenesis. We crossed Tert heterozygous knockout mice (mTert +/- ) for 26 generations, during which time there was progressive shortening of telomeres, and obtained primary skin fibroblasts from mTert +/+ and mTert -/- progeny of the 26th cross. As a consequence of insufficient telomerase activities in prior generations, both mTert +/+ and mTert -/- fibroblasts showed comparable and extremely short telomere length. However, mTert -/- cells approached cellular senescence faster and exhibited a significantly higher rate of malignant transformation than mTert +/+ cells. Furthermore, an evident up-regulation of telomerase reverse-transcriptase (TERT) expression was detected in mTert +/+ cells at the presenescence stage. Moreover, removal or down-regulation of TERT expression in mTert +/+ and human primary fibroblast cells via CRISPR/Cas9 or shRNA recapitulated mTert -/- phenotypes of accelerated senescence and transformation, and overexpression of TERT in mTert -/- cells rescued these phenotypes. Taking these data together, this study suggests that TERT has a previously underappreciated, protective role in buffering senescence stresses due to short, dysfunctional telomeres, and preventing malignant transformation.


Assuntos
Transformação Celular Neoplásica/genética , Senescência Celular/genética , Telomerase/genética , Telomerase/metabolismo , Animais , Ciclo Celular/genética , Células Cultivadas , Fibroblastos/patologia , Expressão Gênica , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fenótipo , Telômero/patologia
15.
Mol Cell ; 76(1): 11-26.e7, 2019 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-31400850

RESUMO

Alternative lengthening of telomeres (ALT) is a homology-directed repair (HDR) mechanism of telomere elongation that controls proliferation in aggressive cancers. We show that the disruption of RAD51-associated protein 1 (RAD51AP1) in ALT+ cancer cells leads to generational telomere shortening. This is due to RAD51AP1's involvement in RAD51-dependent homologous recombination (HR) and RAD52-POLD3-dependent break induced DNA synthesis. RAD51AP1 KO ALT+ cells exhibit telomere dysfunction and cytosolic telomeric DNA fragments that are sensed by cGAS. Intriguingly, they activate ULK1-ATG7-dependent autophagy as a survival mechanism to mitigate DNA damage and apoptosis. Importantly, RAD51AP1 protein levels are elevated in ALT+ cells due to MMS21 associated SUMOylation. Mutation of a single SUMO-targeted lysine residue perturbs telomere dynamics. These findings indicate that RAD51AP1 is an essential mediator of the ALT mechanism and is co-opted by post-translational mechanisms to maintain telomere length and ensure proliferation of ALT+ cancer cells.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Neoplasias/metabolismo , Proteínas de Ligação a RNA/metabolismo , Homeostase do Telômero , Telômero/metabolismo , Autofagia , Proteína 7 Relacionada à Autofagia/genética , Proteína 7 Relacionada à Autofagia/metabolismo , Proteína Homóloga à Proteína-1 Relacionada à Autofagia/genética , Proteína Homóloga à Proteína-1 Relacionada à Autofagia/metabolismo , Proliferação de Células , DNA Polimerase III/genética , DNA Polimerase III/metabolismo , Proteínas de Ligação a DNA/genética , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Células HeLa , Recombinação Homóloga , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Ligases/genética , Ligases/metabolismo , Lisina , Neoplasias/genética , Neoplasias/patologia , Nucleotidiltransferases/genética , Nucleotidiltransferases/metabolismo , Estabilidade Proteica , Proteínas de Ligação a RNA/genética , Proteína Rad52 de Recombinação e Reparo de DNA/genética , Proteína Rad52 de Recombinação e Reparo de DNA/metabolismo , Transdução de Sinais , Sumoilação , Telômero/genética , Telômero/patologia
16.
Mol Cell ; 76(1): 27-43.e11, 2019 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-31447390

RESUMO

Cancer cells acquire unlimited proliferative capacity by either re-expressing telomerase or inducing alternative lengthening of telomeres (ALT), which relies on telomere recombination. Here, we show that ALT recombination requires coordinate regulation of the SMX and BTR complexes to ensure the appropriate balance of resolution and dissolution activities at recombining telomeres. Critical to this control is SLX4IP, which accumulates at ALT telomeres and interacts with SLX4, XPF, and BLM. Loss of SLX4IP increases ALT-related phenotypes, which is incompatible with cell growth following concomitant loss of SLX4. Inactivation of BLM is sufficient to rescue telomere aggregation and the synthetic growth defect in this context, suggesting that SLX4IP favors SMX-dependent resolution by antagonizing promiscuous BLM activity during ALT recombination. Finally, we show that SLX4IP is inactivated in a subset of ALT-positive osteosarcomas. Collectively, our findings uncover an SLX4IP-dependent regulatory mechanism critical for telomere maintenance in ALT cancer cells.


Assuntos
Neoplasias Ósseas/enzimologia , Proteínas de Transporte/metabolismo , Osteossarcoma/enzimologia , RecQ Helicases/metabolismo , Homeostase do Telômero , Telômero/metabolismo , Animais , Neoplasias Ósseas/genética , Neoplasias Ósseas/patologia , Proteínas de Transporte/genética , Proliferação de Células , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Feminino , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Células HeLa , Humanos , Camundongos Knockout , Camundongos SCID , Osteossarcoma/genética , Osteossarcoma/patologia , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , RecQ Helicases/genética , Recombinases/genética , Recombinases/metabolismo , Transdução de Sinais , Telômero/genética , Telômero/patologia
17.
Cancer Epidemiol Biomarkers Prev ; 28(11): 1868-1875, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31427306

RESUMO

BACKGROUND: Leukocyte telomere length has been associated with risk of subsequent pancreatic cancer. Few prospective studies have evaluated the association of prediagnostic leukocyte telomere length with pancreatic cancer survival. METHODS: We prospectively examined the association of prediagnostic leukocyte telomere length with overall survival (OS) time among 423 participants diagnosed with pancreatic adenocarcinoma between 1984 and 2008 within the Health Professionals Follow-up Study, Nurses' Health Study, Physicians' Health Study, and Women's Health Initiative. We measured prediagnostic leukocyte telomere length in banked blood samples using quantitative PCR. Cox proportional hazards models were used to estimate HRs for OS with adjustment for potential confounders. We also evaluated 10 SNPs at the telomerase reverse transcriptase locus. RESULTS: Shorter prediagnostic leukocyte telomere length was associated with reduced OS among patients with pancreatic cancer (P trend = 0.04). The multivariable-adjusted HR for OS comparing the lowest with highest quintiles of leukocyte telomere length was 1.39 (95% confidence interval, 1.01-1.93), corresponding to a 3-month difference in median OS time. In an analysis excluding cases with blood collected within 2 years of cancer diagnosis, the association was moderately stronger (HR, 1.55; 95% confidence interval, 1.09-2.21; comparing the lowest with highest quintiles; P trend = 0.01). No prognostic association or effect modification for the prognostic association of prediagnostic leukocyte telomere length was noted in relation to the studied SNPs. CONCLUSIONS: Prediagnostic leukocyte telomere length was associated with pancreatic cancer survival. IMPACT: Prediagnostic leukocyte telomere length can be a prognostic biomarker in pancreatic cancer.


Assuntos
Leucócitos/metabolismo , Neoplasias Pancreáticas/fisiopatologia , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Pancreáticas/mortalidade , Estudos Prospectivos , Fatores de Risco , Análise de Sobrevida , Telômero/patologia
18.
Cell Death Dis ; 10(7): 527, 2019 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-31296842

RESUMO

G-quadruplex telomeric secondary structures represent natural replication fork barriers and must be resolved to permit efficient replication. Stabilization of telomeric G4 leads to telomere dysfunctions demonstrated by telomere shortening or damage, resulting in genome instability and apoptosis. Chemical compounds targeting G4 structures have been reported to induce telomere disturbance and tumor suppression. Here, virtual screening was performed in a natural compound library using PyRx to identify novel G4 ligands. Emodin was identified as one of the best candidates, showing a great G4-binding potential. Subsequently, we confirmed that emodin could stabilize G4 structures in vitro and trigger telomere dysfunctions including fragile telomeres, telomere loss, and telomeric DNA damage. However, this telomere disturbance could be rescued by subsequent elevation of telomerase activity; in contrast, when we treated the cells with the telomerase inhibitor BIBR1532 upon emodin treatment, permanent telomere disturbance and obvious growth inhibition of 4T1-cell xenograft tumors were observed in mice. Taken together, our results show for the first time that emodin-induced telomeric DNA damage can upregulate telomerase activity, which may weaken its anticancer effect. The combined use of emodin and the telomerase inhibitor synergistically induced telomere dysfunction and inhibited tumor generation.


Assuntos
Aminobenzoatos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Emodina/uso terapêutico , Quadruplex G/efeitos dos fármacos , Naftalenos/uso terapêutico , Telomerase/antagonistas & inibidores , Encurtamento do Telômero/efeitos dos fármacos , Telômero/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Emodina/química , Humanos , Ligantes , Camundongos , Camundongos Endogâmicos BALB C , Simulação de Acoplamento Molecular , Neoplasias/tratamento farmacológico , Neoplasias/enzimologia , Neoplasias/genética , Telomerase/metabolismo , Telômero/química , Telômero/enzimologia , Telômero/patologia , Transplante Heterólogo
19.
High Blood Press Cardiovasc Prev ; 26(4): 321-329, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31325087

RESUMO

Cardiovascular disease (CVD) remains the leading cause of morbility and mortality worldwide. The identification of common cardiovascular risk factors has led to the development of effective treatments that enabled a significant reduction of the global cardiovascular disease burden. However, a significant proportion of cardiovascular risk remains unexplained by these risk factors leaving many individuals at risk of cardiovascular events despite good control of the risk factors. Recent randomized clinical trials and Mendelian randomization studies have suggested that inflammation explains a significant proportion of the residual cardiovascular risk in subjects with good control of risk factors. An accelerated process of vascular ageing is increasingly recognized as a potential mechanism by which inflammation might increase the risk of CVD. In turn, cellular ageing represents an important source of inflammation within the vascular wall, potentially creating a vicious cycle that might promote progression of atherosclerosis, independently from the individual cardiovascular risk factor burden. In this review, we summarise current evidence suggesting a role for biological ageing in CVD and how inflammation might act as a key mediator of this association.


Assuntos
Envelhecimento/metabolismo , Doenças Cardiovasculares/metabolismo , Mediadores da Inflamação/metabolismo , Inflamação/metabolismo , Telômero/metabolismo , Fatores Etários , Envelhecimento/genética , Envelhecimento/patologia , Animais , Doenças Cardiovasculares/genética , Doenças Cardiovasculares/patologia , Doenças Cardiovasculares/fisiopatologia , Senescência Celular , Humanos , Inflamação/genética , Inflamação/patologia , Inflamação/fisiopatologia , Medição de Risco , Fatores de Risco , Transdução de Sinais , Telômero/genética , Telômero/patologia , Homeostase do Telômero , Encurtamento do Telômero , Fatores de Tempo
20.
EMBO Mol Med ; 11(7): e10292, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31273934

RESUMO

Telomeres are considered as universal anti-cancer targets, as telomere maintenance is essential to sustain indefinite cancer growth. Mutations in telomerase, the enzyme that maintains telomeres, are among the most frequently found in cancer. In addition, mutations in components of the telomere protective complex, or shelterin, are also found in familial and sporadic cancers. Most efforts to target telomeres have focused in telomerase inhibition; however, recent studies suggest that direct targeting of the shelterin complex could represent a more effective strategy. In particular, we recently showed that genetic deletion of the TRF1 essential shelterin protein impairs tumor growth in aggressive lung cancer and glioblastoma (GBM) mouse models by direct induction of telomere damage independently of telomere length. Here, we screen for TRF1 inhibitory drugs using a collection of FDA-approved drugs and drugs in clinical trials, which cover the majority of pathways included in the Reactome database. Among other targets, we find that inhibition of several kinases of the Ras pathway, including ERK and MEK, recapitulates the effects of Trf1 genetic deletion, including induction of telomeric DNA damage, telomere fragility, and inhibition of cancer stemness. We further show that both bRAF and ERK2 kinases phosphorylate TRF1 in vitro and that these modifications are essential for TRF1 location to telomeres in vivo. Finally, we use these new TRF1 regulatory pathways as the basis to discover novel drug combinations based on TRF1 inhibition, with the goal of effectively blocking potential resistance to individual drugs in patient-derived glioblastoma xenograft models.


Assuntos
Glioma/tratamento farmacológico , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Proteínas de Neoplasias , Inibidores de Proteínas Quinases/farmacologia , Telômero/metabolismo , Animais , Linhagem Celular Tumoral , Feminino , Deleção de Genes , Glioma/genética , Glioma/metabolismo , Glioma/patologia , Humanos , Sistema de Sinalização das MAP Quinases/genética , Camundongos , Camundongos Nus , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Telômero/genética , Telômero/patologia , Proteína 1 de Ligação a Repetições Teloméricas/genética , Proteína 1 de Ligação a Repetições Teloméricas/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
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