Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Am J Pathol ; 190(8): 1643-1656, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32416097

RESUMO

Prognosis in young patients with breast cancer is generally poor, yet considerable differences in clinical outcomes between individual patients exist. To understand the genetic basis of the disparate clinical courses, tumors were collected from 34 younger women, 17 with good and 17 with poor outcomes, as determined by disease-specific survival during a follow-up period of 17 years. The clinicopathologic parameters of the tumors were complemented with DNA image cytometry profiles, enumeration of copy numbers of eight breast cancer genes by multicolor fluorescence in situ hybridization, and targeted sequence analysis of 563 cancer genes. Both groups included diploid and aneuploid tumors. The degree of intratumor heterogeneity was significantly higher in aneuploid versus diploid cases, and so were gains of the oncogenes MYC and ZNF217. Significantly more copy number alterations were observed in the group with poor outcome. Almost all tumors in the group with long survival were classified as luminal A, whereas triple-negative tumors predominantly occurred in the short survival group. Mutations in PIK3CA were more common in the group with good outcome, whereas TP53 mutations were more frequent in patients with poor outcomes. This study shows that TP53 mutations and the extent of genomic imbalances are associated with poor outcome in younger breast cancer patients and thus emphasize the central role of genomic instability vis-a-vis tumor aggressiveness.


Assuntos
Neoplasias da Mama/genética , Variações do Número de Cópias de DNA , Instabilidade Genômica , Mutação , Proteína Supressora de Tumor p53/genética , Adulto , Biomarcadores Tumorais/genética , Neoplasias da Mama/mortalidade , Neoplasias da Mama/patologia , Intervalo Livre de Doença , Feminino , Regulação Neoplásica da Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Pessoa de Meia-Idade , Prognóstico , Taxa de Sobrevida
2.
BMC Psychiatry ; 21(1): 540, 2021 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-34717567

RESUMO

BACKGROUND: Mental disorders are prevalent and cause considerable burden of disease. Exercise has been shown to be efficacious to treat major depressive disorders, insomnia, panic disorder with and without agoraphobia and post traumatic stress disorder (PTSD). METHODS: This pragmatic, two arm, multi-site randomised controlled trial will evaluate the efficacy and cost-effectiveness of the manualized, group-based six-months exercise intervention "ImPuls", among physically inactive patients with major depressive disorders, insomnia, panic disorder, agoraphobia and PTSD within a naturalistic outpatient context in Germany. A minimum of 375 eligible outpatients from 10 different study sites will be block-randomized to either ImPuls in addition to treatment as usual (TAU) or TAU only. ImPuls will be conducted by trained exercise therapists and delivered in groups of six patients. The program will combine (a) moderate to vigorous aerobic exercise carried out two-three times a week for at least 30 min with (b) behavior change techniques for sustained exercise behavior change. All outcomes will be assessed pre-treatment, post-treatment (six months after randomization) and at follow-up (12 months after randomization). Primary outcome will be self-reported global symptom severity assessed with the Brief Symptom Inventory (BSI-18). Secondary outcomes will be accelerometry-based moderate to vigorous physical activity, self-reported exercise, disorder-specific symptoms, quality-adjusted life years (QALY) and healthcare costs. Intention-to-treat analyses will be conducted using mixed models. Cost-effectiveness and cost-utility analysis will be conducted using incremental cost-effectiveness and cost-utility ratios. DISCUSSION: Despite its promising therapeutic effects, exercise programs are currently not provided within the outpatient mental health care system in Germany. This trial will inform service providers and policy makers about the efficacy and cost-effectiveness of the group-based exercise intervention ImPuls within a naturalistic outpatient health care setting. Group-based exercise interventions might provide an option to close the treatment gap within outpatient mental health care settings. TRIAL REGISTRATION: The study was registered in the German Clinical Trials Register (ID: DRKS00024152 , 05/02/2021).


Assuntos
Transtorno Depressivo Maior , Agorafobia , Análise Custo-Benefício , Terapia por Exercício , Humanos , Estudos Multicêntricos como Assunto , Ensaios Clínicos Pragmáticos como Assunto , Anos de Vida Ajustados por Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto
3.
Int J Mol Sci ; 21(3)2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-32046186

RESUMO

Bladder cancer is one of the more common malignancies in humans and the most expensive tumor for treating in the Unites States (US) and Europe due to the need for lifelong surveillance. Non-invasive tests approved by the FDA have not been widely adopted in routine diagnosis so far. Therefore, we aimed to characterize the two putative tumor suppressor genes ECRG4 and ITIH5 as novel urinary DNA methylation biomarkers that are suitable for non-invasive detection of bladder cancer. While assessing the analytical performance, a spiking experiment was performed by determining the limit of RT112 tumor cell detection (range: 100-10,000 cells) in the urine of healthy donors in dependency of the processing protocols of the RWTH cBMB. Clinically, urine sediments of 474 patients were analyzed by using quantitative methylation-specific PCR (qMSP) and Methylation Sensitive Restriction Enzyme (MSRE) qPCR techniques. Overall, ECRG4-ITIH5 showed a sensitivity of 64% to 70% with a specificity ranging between 80% and 92%, i.e., discriminating healthy, benign lesions, and/or inflammatory diseases from bladder tumors. When comparing single biomarkers, ECRG4 achieved a sensitivity of 73%, which was increased by combination with the known biomarker candidate NID2 up to 76% at a specificity of 97%. Hence, ITIH5 and, in particular, ECRG4 might be promising candidates for further optimizing current bladder cancer biomarker panels and platforms.


Assuntos
Biomarcadores Tumorais/urina , Metilação de DNA , Proteínas Secretadas Inibidoras de Proteinases/genética , Proteínas Supressoras de Tumor/genética , Neoplasias da Bexiga Urinária/urina , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/normas , Linhagem Celular Tumoral , Feminino , Humanos , Limite de Detecção , Masculino , Pessoa de Meia-Idade , Proteínas Secretadas Inibidoras de Proteinases/normas , Reprodutibilidade dos Testes , Proteínas Supressoras de Tumor/normas , Neoplasias da Bexiga Urinária/diagnóstico
4.
Genes Chromosomes Cancer ; 58(11): 783-797, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31334584

RESUMO

Aberrant methylation of DNA is supposed to be a major and early driver of colonic adenoma development, which may result in colorectal cancer (CRC). Although gene methylation assays are used already for CRC screening, differential epigenetic alterations of recurring and nonrecurring colorectal adenomas have yet not been systematically investigated. Here, we collected a sample set of formalin-fixed paraffin-embedded colorectal low-grade adenomas (n = 72) consisting of primary adenomas without and with recurrence (n = 59), recurrent adenomas (n = 10), and normal mucosa specimens (n = 3). We aimed to unveil differentially methylated CpG positions (DMPs) across the methylome comparing not only primary adenomas without recurrence vs primary adenomas with recurrence but also primary adenomas vs recurrent adenomas using the Illumina Human Methylation 450K BeadChip array. Unsupervised hierarchical clustering exhibited a significant association of methylation patterns with histological adenoma subtypes. No significant DMPs were identified comparing primary adenomas with and without recurrence. Despite that, a total of 5094 DMPs (false discovery rate <0.05; fold change >10%) were identified in the comparisons of recurrent adenomas vs primary adenomas with recurrence (674; 98% hypermethylated), recurrent adenomas vs primary adenomas with and without recurrence (241; 99% hypermethylated) and colorectal adenomas vs normal mucosa (4179; 46% hypermethylated). DMPs in cytosine-phosphate-guanine (CpG) islands were frequently hypermethylated, whereas open sea- and shelf-regions exhibited hypomethylation. Gene ontology analysis revealed enrichment of genes associated with the immune system, inflammatory processes, and cancer pathways. In conclusion, our methylation data could assist in establishing a more robust and reproducible histological adenoma classification, which is a prerequisite for improving surveillance guidelines.


Assuntos
Neoplasias Colorretais/genética , Ilhas de CpG/genética , Epigênese Genética/genética , Adenoma/genética , Idoso , Biomarcadores Tumorais/genética , Citosina , Metilação de DNA/genética , Detecção Precoce de Câncer/métodos , Epigenômica , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Genoma Humano , Guanina , Técnicas Histológicas/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/genética , Fosfatos , Regiões Promotoras Genéticas/genética
5.
Int J Cancer ; 144(7): 1561-1573, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30229897

RESUMO

Colorectal adenomas are common precancerous lesions with the potential for malignant transformation to colorectal adenocarcinoma. Endoscopic polypectomy provides an opportunity for cancer prevention; however, recurrence rates are high. We collected formalin-fixed paraffin-embedded tissue of 15 primary adenomas with recurrence, 15 adenomas without recurrence, and 14 matched pair samples (primary adenoma and the corresponding recurrent adenoma). The samples were analysed by array-comparative genomic hybridisation (aCGH) and single-cell multiplex interphase fluorescence in situ hybridisation (miFISH) to understand clonal evolution, to examine the dynamics of copy number alterations (CNAs) and to identify molecular markers for recurrence prediction. The miFISH probe panel consisted of 14 colorectal carcinogenesis-relevant genes (COX2, PIK3CA, APC, CLIC1, EGFR, MYC, CCND1, CDX2, CDH1, TP53, HER2, SMAD7, SMAD4 and ZNF217), and a centromere probe (CEP10). The aCGH analysis confirmed the genetic landscape typical for colorectal tumorigenesis, that is, CNAs of chromosomes 7, 13q, 18 and 20q. Focal aberrations (≤10 Mbp) were mapped to chromosome bands 6p22.1-p21.33 (33.3%), 7q22.1 (31.4%) and 16q21 (29.4%). MiFISH detected gains of EGFR (23.6%), CDX2 (21.8%) and ZNF217 (18.2%). Most adenomas exhibited a major clone population which was accompanied by multiple smaller clone populations. Gains of CDX2 were exclusively seen in primary adenomas with recurrence (25%) compared to primary adenomas without recurrence (0%). Generation of phylogenetic trees for matched pair samples revealed four distinct patterns of clonal dynamics. In conclusion, adenoma development and recurrence are complex genetic processes driven by multiple CNAs whose evaluations by miFISH, with emphasis on CDX2, might serve as a predictor of recurrence.


Assuntos
Adenoma/genética , Fator de Transcrição CDX2/genética , Neoplasias Colorretais/genética , Recidiva Local de Neoplasia/genética , Análise de Célula Única/métodos , Idoso , Biomarcadores Tumorais/genética , Aberrações Cromossômicas , Evolução Clonal , Hibridização Genômica Comparativa , Variações do Número de Cópias de DNA , Feminino , Humanos , Hibridização in Situ Fluorescente , Masculino , Pessoa de Meia-Idade
6.
J Hand Surg Am ; 42(1): e67-e74, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28052837

RESUMO

Traumatic nail bed injuries to the hand are a common problem for hand surgeons. Whereas the majority of those are treated with primary repair, the remainder present significant surgical challenges to address residual soft tissue defects. In this article, we present our approach to treating injuries to the fingertips utilizing single-layer bovine acellular dermal matrix grafts.


Assuntos
Derme Acelular , Unhas/lesões , Unhas/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Animais , Bovinos , Humanos
7.
Carcinogenesis ; 35(3): 727-36, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24265292

RESUMO

Inter-α-trypsin inhibitor heavy chain 5 (ITIH5) has been associated with tumour suppression in various cancers. However, its putative role in bladder cancer is completely unknown. Therefore, we initiated a study analysing ITIH5 expression as well as its prognostic and functional impact on human urothelial cancers (UCs). Expression analysis showed a clear down-regulation of ITIH5 mRNA in 61% (n = 45) of UCs, especially in muscle-invasive tumours (P < 0.001). ITIH5 loss in UCs was further evident on protein level (65.5%, n = 55) as detected by immunohistochemistry. DNA methylation analysis demonstrated tumour-specific ITIH5 promoter methylation in 50% of papillary none-invasive pTa (n = 30) and 68% of invasive (n = 28) UCs. Aberrant ITIH5 promoter methylation in bladder tumours was tightly linked (P < 0.001) with loss of ITIH5 mRNA expression, which was furthermore functionally confirmed by demethylation analysis in cell lines. Pyrosequencing analysis revealed that ITIH5 promoter hypermethylation was closely associated with progressive bladder cancers. Subsequently, a large cohort (n = 120) of clinically challenging pT1 high-grade UC was analysed for ITIH5 expression. Of clinical significance, we found an association between loss of ITIH5 expression and unfavourable prognosis of UC patients without distant metastasis at first diagnosis (recurrence-free survival; hazard ratio: 4.35, P = 0.048). Functionally, ITIH5 re-expression in human RT112 bladder cancer cells led to both suppression of cell migration and inhibition of colony spreading. Hence, we provide evidence that down-regulation of ITIH5 by aberrant DNA hypermethylation may provoke invasive phenotypes in human bladder cancer. Moreover, ITIH5 protein might become a prognostic biomarker for relapse risk stratification in high-grade UC patients.


Assuntos
Biomarcadores Tumorais/genética , Epigênese Genética , Inativação Gênica , Recidiva Local de Neoplasia/genética , Proteínas Secretadas Inibidoras de Proteinases/genética , Neoplasias da Bexiga Urinária/genética , Metilação de DNA , Progressão da Doença , Humanos , Regiões Promotoras Genéticas , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Neoplasias da Bexiga Urinária/patologia
8.
Lancet Psychiatry ; 11(6): 417-430, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38670127

RESUMO

BACKGROUND: Globally, mental health conditions pose a substantial burden of disease. Despite the availability of evidence-based pharmacological and psychological treatments, the symptoms of a substantial subgroup of patients do not respond to these interventions, and only a minority of patients have access to them. This study aimed to assess the efficacy of ImPuls, a 6-month transdiagnostic group exercise intervention, plus treatment-as-usual, compared with treatment-as-usual alone in outpatients with various mental disorders. METHODS: In this pragmatic, two-arm, multisite, randomised controlled trial in Germany, ten outpatient rehabilitative and medical care facilities were involved as study sites. Participants were outpatients diagnosed according to ICD-10 with one or more of the following disorders based on structured clinical interviews: moderate or severe depression, primary insomnia, post-traumatic stress disorder (PTSD), panic disorder, or agoraphobia. Participants were required to be aged between 18 years and 65 years, insured by the health insurers Allgemeine Ortskrankenkasse Baden-Württemberg or Techniker Krankenkasse, fluent in German, and without medical contraindications for exercise. Blocks of six participants were randomly allocated to ImPuls plus treatment-as-usual or treatment-as-usual alone (allocation ratio: 1:1), stratified by study site. The randomisation sequence was generated by an external data manager. The team responsible for data collection and management was masked to the randomisation sequence. The ImPuls intervention comprised evidence-based outdoor exercises lasting 30 min, and aimed at achieving at least moderate intensity. It also incorporated behavioural change techniques targeting motivational and volitional determinants of exercise behaviour. Treatment-as-usual was representative of typical outpatient health care in Germany, allowing patients access to any standard treatments. The primary outcome was global symptom severity at 6 months after randomisation, measured using self-report on the Brief Symptom Inventory (BSI-18) and analysed in the intention-to-treat sample. No individuals with lived experience of mental illness were involved in conducting the study or writing the final publication. Safety was assessed in all participants. The trial was registered with the German Clinical Trials Register (DRKS00024152) with a completion date of June 30, 2024. FINDINGS: 600 patients provided informed consent, were recruited to the study, and underwent a diagnostic interview between Jan 1, 2021, and May 31, 2022. Following this, 199 were excluded on the basis of inclusion and exclusion criteria and one withdrew consent during the baseline assessment. Of the 400 eligible participants, 284 (71%) self-identified as female, 106 (27%) self-identified as male, and nine (2%) self-identified as other. The mean age was 42·20 years (SD 13·23; range 19-65). Ethnicity data were not assessed. 287 (72%) participants met the criteria for moderate or severe depression, 81 (20%) for primary insomnia, 37 (9%) for agoraphobia, 46 (12%) for panic disorder, and 72 (18%) for PTSD. 199 participants were allocated to the intervention group of ImPuls plus treatment-as-usual and 201 to the control group of treatment-as-usual alone. 38 (19%) participants did not receive the minimum ImPuls intervention dose. ImPuls plus treatment-as-usual demonstrated superior efficacy to treatment-as-usual alone in reducing global symptom severity, with an adjusted difference on BSI-18 of 4·11 (95% CI 1·74-6·48; d=0·35 [95% CI 0·14-0·56]; p=0·0007) at 6 months. There were no significant differences in the total number of adverse events or serious adverse events between the two groups. There was one serious adverse event (male, torn ligament) related to the intervention. INTERPRETATION: ImPuls is an efficacious transdiagnostic adjunctive treatment in outpatient mental health care. Our findings suggest that exercise therapy should be implemented in outpatient mental health care as an adjunctive transdiagnostic treatment for mental disorders such as depression, insomnia, panic disorder, agoraphobia, and PTSD. Transdiagnostic group exercise interventions might ameliorate the existing disparity in care provision between the many individuals in need of evidence-based treatment and the few who are receiving it. FUNDING: The German Innovation Fund of the Federal Joint Committee of Germany.


Assuntos
Terapia por Exercício , Transtornos Mentais , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Assistência Ambulatorial/métodos , Terapia por Exercício/métodos , Alemanha , Transtornos Mentais/terapia , Pacientes Ambulatoriais/estatística & dados numéricos , Psicoterapia de Grupo/métodos , Resultado do Tratamento
9.
Trials ; 24(1): 330, 2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-37189210

RESUMO

BACKGROUND: Evidence suggests that patients suffering from different mental disorders benefit from exercise programs combined with behavior change techniques. Based on this evidence, we have developed an exercise program (ImPuls) specifically designed to provide an additional treatment option in the outpatient mental health care system. The implementation of such complex programs into the outpatient context requires research that goes beyond the evaluation of effectiveness, and includes process evaluation. So far, process evaluation related to exercise interventions has rarely been conducted. As part of a current pragmatic randomized controlled trial evaluating ImPuls treatment effects, we are therefore carrying out comprehensive process evaluation according to the Medical Research Council (MRC) framework. The central aim of our process evaluation is to support the findings of the ongoing randomized controlled trial. METHODS: The process evaluation follows a mixed-methods approach. We collect quantitative data via online-questionnaires from patients, exercise therapists, referring healthcare professionals and managers of outpatient rehabilitative and medical care facilities before, during, and after the intervention. In addition, documentation data as well as data from the ImPuls smartphone application are collected. Quantitative data is complemented by qualitative interviews with exercise therapists as well as a focus-group interview with managers. Treatment fidelity will be assessed through the rating of video-recorded sessions. Quantitative data analysis includes descriptive as well as mediation and moderation analyses. Qualitative data will be analyzed via qualitative content analysis. DISCUSSION: The results of our process evaluation will complement the evaluation of effectiveness and cost-effectiveness and will, for example, provide important information about mechanisms of impact, structural prerequisites, or provider qualification that may support the decision-making process of health policy stakeholders. It might contribute to paving the way for exercise programs like ImPuls to be made successively available for patients with heterogeneous mental disorders in the German outpatient mental health care system. TRIAL REGISTRATION: The parent clinical study was registered in the German Clinical Trials Register (ID: DRKS00024152, registered 05/02/2021, https://drks.de/search/en/trial/DRKS00024152 ).


Assuntos
Transtornos Mentais , Aplicativos Móveis , Humanos , Exercício Físico , Pessoal de Saúde , Transtornos Mentais/diagnóstico , Transtornos Mentais/terapia , Pacientes Ambulatoriais , Ensaios Clínicos Controlados Aleatórios como Assunto , Ensaios Clínicos Pragmáticos como Assunto
10.
Sci Rep ; 10(1): 17895, 2020 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-33087752

RESUMO

Human cancer cell lines are frequently used as model systems to study molecular mechanisms and genetic changes in cancer. However, the model is repeatedly criticized for its lack of proximity to original patient tumors. Therefore, understanding to what extent cell lines cultured under artificial conditions reflect the phenotypic and genomic profiles of their corresponding parental tumors is crucial when analyzing their biological properties. To directly compare molecular alterations between patient tumors and derived cell lines, we have established new cancer cell lines from four patients with gastrointestinal tumors. Tumor entities comprised esophageal cancer, colon cancer, rectal cancer and pancreatic cancer. Phenotype and genotype of both patient tumors and derived low-passage cell lines were characterized by immunohistochemistry (22 different antibodies), array-based comparative genomic hybridization and targeted next generation sequencing (48-gene panel). The immunophenotype was highly consistent between patient tumors and derived cell lines; the expression of most markers in cell lines was concordant with the respective parental tumor and characteristic for the respective tumor entities in general. The chromosomal aberration patterns of the parental tumors were largely maintained in the cell lines and the distribution of gains and losses was typical for the respective cancer entity, despite a few distinct differences. Cancer gene mutations (e.g., KRAS, TP53) and microsatellite status were also preserved in the respective cell line derivates. In conclusion, the four examined newly established cell lines exhibited a phenotype and genotype closely recapitulating their parental tumor. Hence, newly established cancer cell lines may be useful models for further pharmacogenomic studies.


Assuntos
Neoplasias Gastrointestinais/genética , Neoplasias Gastrointestinais/imunologia , Linhagem Celular Tumoral , Separação Celular , Aberrações Cromossômicas , Hibridização Genômica Comparativa , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Imuno-Histoquímica , Repetições de Microssatélites/genética , Mutação , Fenótipo , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteína Supressora de Tumor p53/genética
11.
J Wrist Surg ; 8(2): 108-111, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30941249

RESUMO

Background Open carpal tunnel release (CTR) is one of the most commonly performed operative procedures with operative duration being a primary metric of operating room efficiency. The purpose of this study was to identify factors associated with prolonged operative duration, in performing CTR. Materials and Methods CTR cases performed by a single surgeon from September 2013 to October 2015 were reviewed. Patient age at the time of surgery, sex, location of surgery (specialty orthopaedic hospital versus ambulatory surgery center), body mass index (BMI), American Society of Anesthesiologists classification, total operative duration (TOD), and procedure time (PT) were recorded. Obesity was defined as BMI > 30 and morbid obesity was defined as BMI > 35. Data were analyzed to identify factors associated with prolonged TOD or PT. Results One hundred and nine consecutive patients underwent isolated CTR. Mean age at time of surgery was 62 years (range: 24-92 years). Nonobese patients were found to have significantly shorter TOD than obese patients (22.3 vs. 24.4 minutes). Similarly, patients who were not morbidly obese had significantly shorter TOD than morbidly obese patients (22.6 vs. 26 minutes). No other factors were associated with prolonged TOD. No difference in PT was found between normal weight, obese, and morbidly obese groups. Conclusions TOD, but not procedure time, is significantly affected by obesity. Our findings are relevant when scheduling and preparing obese patients for surgery, which may have a significant impact on health resource utilization. Level of Evidence This is a Level III, economic/decision analysis study.

12.
Mol Cell Biol ; 29(1): 187-200, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18936161

RESUMO

In the budding yeast Saccharomyces cerevisiae, the Hsp104-mediated disaggregation of protein aggregates is essential for thermotolerance and to facilitate the maintenance of prions. In humans, protein aggregation is associated with neuronal death and dysfunction in many neurodegenerative diseases. Mechanisms of aggregation surveillance that regulate protein disaggregation are likely to play a major role in cell survival after acute stress. However, such mechanisms have not been studied. In a screen using the yeast gene deletion library for mutants unable to survive an aggregation-inducing heat stress, we find that SSD1 is required for Hsp104-mediated protein disaggregation. SSD1 is a polymorphic gene that plays a role in cellular integrity, longevity, and pathogenicity in yeast. Allelic variants of SSD1 regulate the level of thermotolerance and cell wall remodeling. We have shown that Ssd1 influences the ability of Hsp104 to hexamerize, to interact with the cochaperone Sti1, and to bind protein aggregates. These results provide a paradigm for linking Ssd1-mediated cellular integrity and Hsp104-mediated disaggregation to ensure the survival of cells with fewer aggregates.


Assuntos
Adaptação Fisiológica , Proteínas de Choque Térmico/metabolismo , Estrutura Quaternária de Proteína , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Temperatura , Adaptação Fisiológica/genética , Genes Essenciais , Genoma Fúngico , Resposta ao Choque Térmico , Proteínas Mutantes/química , Proteínas Mutantes/metabolismo , Mutação/genética , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/genética , Trealose/biossíntese
13.
Biochemistry ; 44(34): 11402-16, 2005 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-16114877

RESUMO

The ligand binding and catalytic properties of heavy metal ions have led to the evolution of metal ion-specific pathways for control of their intracellular trafficking and/or elimination. Small MW proteins/domains containing a GMTCXXC metal binding motif in a betaalphabetabetaalphabeta fold are common among proteins controlling the mobility of soft metal ions such as Cu(1+), Zn(2+), and Hg(2+), and the functions of several have been established. In bacterial mercuric ion reductases (MerA), which catalyze reduction of Hg(2+) to Hg(0) as a means of detoxification, one or two repeats of sequences with this fold are highly conserved as N-terminal domains (NmerA) of uncertain function. To simplify functional analysis of NmerA, we cloned and expressed the domain and catalytic core of Tn501 MerA as separate proteins. In this paper, we show Tn501 NmerA to be a stable, soluble protein that binds 1 Hg(2+)/domain and delivers it to the catalytic core at kinetically competent rates. Comparison of steady-state data for full-length versus catalytic core MerA using Hg(glutathione)(2) or Hg(thioredoxin) as substrate demonstrates that the NmerA domain does participate in acquisition and delivery of Hg(2+) to the catalytic core during the reduction catalyzed by full-length MerA, particularly when Hg(2+) is bound to a protein. Finally, comparison of growth curves for glutathione-depleted Escherichia coli expressing either catalytic core, full-length, or a combination of core plus NmerA shows an increased protection of cells against Hg(2+) in the media when NmerA is present, providing the first evidence of a functional role for this highly conserved domain.


Assuntos
Bacillus/enzimologia , Glutationa/deficiência , Mercúrio/metabolismo , Metaloproteínas/metabolismo , Oxirredutases/metabolismo , Sequência de Aminoácidos , Domínio Catalítico , Cátions Bivalentes/metabolismo , Clonagem Molecular , Primers do DNA , Glutationa Redutase , Humanos , Modelos Moleculares , Oxirredutases/química , Reação em Cadeia da Polimerase , Conformação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Espectrofotometria
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA