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1.
Mol Neurobiol ; 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38713439

RESUMO

Spinal cord injury (SCI) often leads to neurological dysfunction, and neuronal cell death is one of the main causes of neurological dysfunction. After SCI, in addition to necrosis, programmed cell death (PCD) occurs in nerve cells. At first, studies recognized only necrosis, apoptosis, and autophagy. In recent years, researchers have identified new forms of PCD, including pyroptosis, necroptosis, ferroptosis, and cuproptosis. Related studies have confirmed that all of these cell death modes are involved in various phases of SCI and affect the direction of the disease through different mechanisms and pathways. Furthermore, regulating neuronal cell death after SCI through various means has been proven to be beneficial for the recovery of neural function. In recent years, emerging therapies for SCI have also provided new potential methods to restore neural function. Thus, the relationship between SCI and cell death plays an important role in the occurrence and development of SCI. This review summarizes and generalizes the relevant research results on neuronal necrosis, apoptosis, autophagy, pyroptosis, necroptosis, ferroptosis, and cuproptosis after SCI to provide a new understanding of neuronal cell death after SCI and to aid in the treatment of SCI.

2.
J Tissue Viability ; 33(1): 96-103, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38155029

RESUMO

Burns are a common type of trauma that seriously affect not only the physical health, but also the mental health and quality of life of the patient. Extracorporeal shock wave therapy (ESWT) is an emerging treatment that has been used in clinical treatment. It has many advantages, including safety, non-invasiveness, efficiency, short treatment duration, fewer complications, and relatively low prices. In clinical settings, ESWT has played an important role in the healing process of burns and the prevention of sequelae. This article reviews the history of ESWT, the mechanism of ESWT to promote burn healing, and the application of ESWT in burns. Current status of ESWT treatment for burns as well as future perspectives for research have been summarized and proposed. However, patients with burns cannot be considered recovered when the wounds have healed, we need some new technology to adjust to the challenges of the future.


Assuntos
Queimaduras , Tratamento por Ondas de Choque Extracorpóreas , Humanos , Qualidade de Vida , Cicatrização , Queimaduras/complicações , Queimaduras/terapia , Fatores de Tempo , Resultado do Tratamento
3.
Sci Rep ; 13(1): 18999, 2023 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-37923777

RESUMO

Uniaxial compression experiments of limestone-coal specimens at different inclination angles (0, 15, 30, 45, and 60°) were conducted using acoustic emission and three-dimensional, extension test digital image correlation, and full-field strain measurement systems to examine how dip angles affect deformation failure. The findings indicate that: (1) specimen groups demonstrate plastic yield characteristics in the pre-peak stage. However, slight variations exist due to inclination angles. (2) The localization zone for deformation evolution closely correlates to primary crack initiation and propagation within coal specimens and to slipping at the rock's and coal's interface. Failure in the coal specimen triggers rebound deformation in limestone when the rock coal inclination angle is set at 15°. Both the rebound deformation amount and its rate exhibit upward trends as a function of the inclination angle. (3) The percentage of pre-peak elastic property density in the combined specimen is augmented from 98.56 to 88.08% as the inclination angle augments and reduces to 75.80%. External energy's conversion into missile performance shows an initial increase followed by a decrease. (4) The energy rate of the acoustic emission (AE) signal exhibits distinct temporal characteristics in the combined specimen that can be associated with quiet, active, and sudden increases.

4.
Mol Immunol ; 162: 125-132, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37677989

RESUMO

Hepatocellular carcinoma (HCC) remains one of the most common and highly fatal malignancies in humans worldwide with increasing prevalence and limited therapeutic options. For many decades, many researchers have attempted to find effective curative methods for HCC and great strides have been made. GPC3 is overexpressed in HCC, but not in normal liver, making it a rational immunotherapeutic target for HCC. GC33, a humanized mAb directed against GPC3, is a safe and well-tolerated therapy choice for patients with HCC, which tested in a phase I trial in advanced HCC patients. Phase II trials of GC33 to evaluate its efficacy and safety in advanced or metastatic HCC, showed no significant differences in overall survival and progression-free survival compared with the placebo. Retrospective analysis indicates that high drug exposure and high CD16 expression may contribute to the clinical efficacy of GC33. Chugai Pharmaceutical has restarted its Phase I trial of GC33, continuing to explore its clinical value targeting GPC3 in solid tumors. To enhance the antitumor potency of GC33, we designed a GPC3/CD16A bispecific antibody (QDEB). In this study, we obtained QDEB at high purity and assessed its effectiveness in the therapy of HCC compared with GC33. In vitro cytotoxicity assays and in vivo experiments demonstrated that QDEB could enhance anti-tumor efficacy compared with GC33. CD16A activation and increased cytokines release were associated with higher anti-tumor activity. In conclusion, this bispecific antibody may possibly help develop new therapeutic strategies for HCC and develop new treatment options in the future.


Assuntos
Anticorpos Biespecíficos , Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/tratamento farmacológico , Estudos Retrospectivos , Neoplasias Hepáticas/tratamento farmacológico , Fatores Imunológicos , Anticorpos Biespecíficos/uso terapêutico , Imunoterapia , Glipicanas
5.
Cancers (Basel) ; 15(11)2023 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-37296892

RESUMO

Liver cancer is closely linked to chronic inflammation. While observational studies have reported positive associations between extrahepatic immune-mediated diseases and systemic inflammatory biomarkers and liver cancer, the genetic association between these inflammatory traits and liver cancer remains elusive and merits further investigation. We conducted a two-sample Mendelian randomization (MR) analysis, using inflammatory traits as exposures and liver cancer as the outcome. The genetic summary data of both exposures and outcome were retrieved from previous genome-wide association studies (GWAS). Four MR methods, including inverse-variance-weighted (IVW), MR-Egger regression, weighted-median, and weighted-mode methods, were employed to examine the genetic association between inflammatory traits and liver cancer. Nine extrahepatic immune-mediated diseases, seven circulating inflammatory biomarkers, and 187 inflammatory cytokines were analyzed in this study. The IVW method suggested that none of the nine immune-mediated diseases were associated with the risk of liver cancer, with odds ratios of 1.08 (95% CI 0.87-1.35) for asthma, 0.98 (95% CI 0.91-1.06) for rheumatoid arthritis, 1.01 (95% CI 0.96-1.07) for type 1 diabetes, 1.01 (95% CI 0.98-1.03) for psoriasis, 0.98 (95% CI 0.89-1.08) for Crohn's disease, 1.02 (95% CI 0.91-1.13) for ulcerative colitis, 0.91 (95% CI 0.74-1.11) for celiac disease, 0.93 (95% CI 0.84-1.05) for multiple sclerosis, and 1.05 (95% CI 0.97-1.13) for systemic lupus erythematosus. Similarly, no significant association was found between circulating inflammatory biomarkers and cytokines and liver cancer after correcting for multiple testing. The findings were consistent across all four MR methods used in this study. Our findings do not support a genetic association between extrahepatic inflammatory traits and liver cancer. However, larger-scale GWAS summary data and more genetic instruments are needed to confirm these findings.

6.
Front Cell Dev Biol ; 11: 1174183, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37077416

RESUMO

Introduction: Hepatocellular carcinoma (HCC) patients may benefit from chemotherapy, but drug resistance is an important obstacle to favorable prognoses. Overcoming drug resistance is an urgent problem to be solved. Methods: Differential expression analysis was used to identify long non-coding RNAs (LncRNAs) that differed in chemotherapy-sensitive and chemotherapy-resistant patients. Machine learning algorithms including random forest (RF), lasso regression (LR), and support vector machines (SVMs) were used to identify important chemotherapy-related LncRNAs. A back propagation (BP) network was then used to validate the predictive capacity of important LncRNAs. The molecular functions of hub LncRNAs were investigated via qRT-PCR and cell proliferation assay. Molecular-docking technique was used to explore candidate drug of targets of hub LncRNA in the model. Results: A total of 125 differentially expressed LncRNAs between sensitive and resistant patients. Seventeen important LncRNAs were identified via RF, and seven factors were identified via LR. With respect to SVM, the top 15 LncRNAs of AvgRank were selected. Five merge chemotherapy-related LncRNAs were used to predict chemotherapy resistance with high accuracy. CAHM was a hub LncRNA of model and expression high in sorafenib resistance cell lines. In addition, the results of CCK8 showed that the sensitivity of HepG2-sorafenib cells to sorafenib was significantly lower than that of HepG2; and the sensitivity of HepG2-sorafenib cells transfected with sh-CAHM was significantly higher than that of Sorafenib. In the non-transfection group, the results of clone formation experiments showed that the number of clones formed by HepG2-sorafenib cells treated with sorafenib was significantly more than that of HepG2; after HepG2-sorafenib cells were transfected with sh-CAHM, the number of clones formed by Sorafenib treatment was significantly higher than that of HepG2 cells. The number was significantly less than that of HepG2-s + sh-NC group. Molecular Docking results indicate that Moschus was candidate drug for target protein of CAHM. Conclusion: Five chemotherapy-related LncRNAs could predict drug resistance in HCC with high accuracy, and the hub LncRNA CAHM has potential as a new biomarker for HCC chemotherapy resistance.

7.
Neural Regen Res ; 18(9): 1861-1868, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36926700

RESUMO

Spinal cord injury is characterized by different aetiologies, complex pathogenesis, and diverse pathological changes. Current treatments are not ideal, and prognosis is generally poor. After spinal cord injury, neurons die due to various forms of cell death. Among them, ferroptosis causes dysfunction after spinal cord injury, and no existing traditional treatments have been indicated to block its occurrence. Meanwhile, emerging therapies using mesenchymal stem cells, extracellular vesicles, and transcranial magnetic stimulation therapy are promising for reversing spinal cord neuronal ferroptosis after spinal cord injury. However, no definitive studies have demonstrated the effectiveness of these approaches. This review summarizes the existing research on the mechanisms of ferroptosis; ferroptosis after spinal cord injury; treatment of spinal cord injury with mesenchymal stem cells, extracellular vesicles, and transcranial magnetic stimulation; and treatment of ferroptosis using mesenchymal stem cells, extracellular vesicles, and transcranial magnetic stimulation. Inhibiting ferroptosis can promote the reversal of neurological dysfunction after spinal cord injury. In addition, mesenchymal stem cells, extracellular vesicles, and transcranial magnetic stimulation can reverse adverse outcomes of spinal cord injury and regulate ferroptosis-related factors. Thus, it can be inferred that mesenchymal stem cells, extracellular vesicles, and transcranial magnetic stimulation have the potential to inhibit ferroptosis after spinal cord injury. This review serves as a reference for future research to confirm these conclusions.

8.
Front Cardiovasc Med ; 9: 1000761, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36465445

RESUMO

Objective: The aim of this study was to test the hypothesis whether serum level of calpains could become a meaningful biomarker for diagnosis of acute lung injury (ALI) in clinical after cardiac surgery using cardiopulmonary bypass (CPB) technology. Methods and results: Seventy consecutive adults underwent cardiac surgery with CPB were included in this prospective study. Based on the American-European Consensus Criteria (AECC), these patients were divided into ALI (n = 20, 28.57%) and non-ALI (n = 50, 71.43%) groups. Serum level of calpains in terms of calpains' activity which was expressed as relative fluorescence unit (RFU) per microliter and measured at beginning of CPB (baseline), 1 h during CPB, end of CPB as well as 1, 12, and 24 h after CPB. Difference of serum level of calpains between two groups first appeared at the end of CPB and remained different at subsequent test points. Univariate and multivariate logistic regression analysis indicated that serum level of calpains 1 h after CPB was an independent predictor for postoperative ALI (OR 1.011, 95% CI 1.001, 1.021, p = 0.033) and correlated with a lower PaO2/FiO2 ratio in the first 2 days (The first day: r = -0.389, p < 0.001 and the second day: r = -0.320, p = 0.007) as well as longer mechanical ventilation time (r = 0.440, p < 0.001), intensive care unit (ICU) length of stay (LOS) (r = 0.419, p < 0.001) and hospital LOS (r = 0.297, p = 0.013). Conclusion: Elevated serum level of calpains correlate with impaired lung function and poor clinical outcomes, indicating serum level of calpains could act as a potential biomarker for postoperative ALI following CPB in adults. Clinical trial registration: [https://clinicaltrials.gov/show/NCT05610475], identifier [NCT05610475].

9.
Artigo em Inglês | MEDLINE | ID: mdl-35547653

RESUMO

Objective: The treatment of choledocholithiasis with duodenal stenosis is a clinical difficult problem. This study aimed to investigate the efficacy and safety of ERCP via gastroscopy in the treatment of choledocholithiasis and duodenal stenosis. Methods: From January 2015 to December 2020, 21 patients with choledocholithiasis with duodenal stenosis who underwent ERCP treatment under gastroscopy in our hospital were enrolled. The patients' case characteristics, ERCP status, and complication rate were analyzed. Results: Among the 21 patients, 17 cases were successful in ERCP, and a total of 29 times ERCPs were performed, with an average of 1.71 times per patient. Among the failures of ERCP, selective deep intubation of common bile duct was unsuccessful in 4 cases. Six patients underwent multiple lithotomies, after the operation, of which 4 patients underwent secondary ERCP lithotomy and 2 patients underwent triple ERCP lithotomy. All patients successfully completed the balloon dilation without serious complications. Two patients developed mild acute pancreatitis after ERCP, and all recovered after medication. Conclusion: In patients with choledocholithiasis and duodenal stenosis, ERCP treatment by gastroscopy has a higher success rate and does not increase the incidence of complications, but there is a problem of cholecystolithiasis recurrence.

10.
Nat Commun ; 12(1): 795, 2021 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-33542217

RESUMO

Epigenetic modifications of DNA play important roles in many biological processes. Identifying readers of these epigenetic marks is a critical step towards understanding the underlying mechanisms. Here, we present an all-to-all approach, dubbed digital affinity profiling via proximity ligation (DAPPL), to simultaneously profile human TF-DNA interactions using mixtures of random DNA libraries carrying different epigenetic modifications (i.e., 5-methylcytosine, 5-hydroxymethylcytosine, 5-formylcytosine, and 5-carboxylcytosine) on CpG dinucleotides. Many proteins that recognize consensus sequences carrying these modifications in symmetric and/or hemi-modified forms are identified. We further demonstrate that the modifications in different sequence contexts could either enhance or suppress TF binding activity. Moreover, many modifications can affect TF binding specificity. Furthermore, symmetric modifications show a stronger effect in either enhancing or suppressing TF-DNA interactions than hemi-modifications. Finally, in vivo evidence suggests that USF1 and USF2 might regulate transcription via hydroxymethylcytosine-binding activity in weak enhancers in human embryonic stem cells.


Assuntos
5-Metilcitosina/análogos & derivados , DNA/metabolismo , Epigenômica/métodos , 5-Metilcitosina/metabolismo , Linhagem Celular , Ilhas de CpG/genética , DNA/genética , Elementos Facilitadores Genéticos , Epigênese Genética , Biblioteca Gênica , Células-Tronco Embrionárias Humanas , Humanos , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Fatores Estimuladores Upstream/genética , Fatores Estimuladores Upstream/isolamento & purificação , Fatores Estimuladores Upstream/metabolismo
12.
J Nematol ; 52: 1-9, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32628823

RESUMO

Chive gnat (Bradysia odoriphaga) is a soil-borne pest of Chinese chives, which causes millions of dollars in yield losses per year. Traditional methods, such as chemical pesticides leave detrimental chemical residues on plants, which potentially threaten human health. To find a sustainable method of reducing the chive gnat, the authors evaluated the effects of waterlogging and the addition of entomopathogenic nematode (EPN) on reducing chive gnat in Chinese chives via three pot experiments and one field demonstration. Results indicated that increasing the duration of waterlogging markedly increases chive gnat mortality. The presence of EPN also caused chive gnat mortality to increase with exposure time. Most importantly, the combination of waterlogging and EPN had synergistic effects on chive gnat mortality; the combination led to higher mortality than using waterlogging and EPN alone. The study demonstrated that a combination of two environmental friendly methods of fungus gnat control could lead to synergistic effects, which may provide novel approaches to economic and environmentally sustainable pest management measures.Chive gnat (Bradysia odoriphaga) is a soil-borne pest of Chinese chives, which causes millions of dollars in yield losses per year. Traditional methods, such as chemical pesticides leave detrimental chemical residues on plants, which potentially threaten human health. To find a sustainable method of reducing the chive gnat, the authors evaluated the effects of waterlogging and the addition of entomopathogenic nematode (EPN) on reducing chive gnat in Chinese chives via three pot experiments and one field demonstration. Results indicated that increasing the duration of waterlogging markedly increases chive gnat mortality. The presence of EPN also caused chive gnat mortality to increase with exposure time. Most importantly, the combination of waterlogging and EPN had synergistic effects on chive gnat mortality; the combination led to higher mortality than using waterlogging and EPN alone. The study demonstrated that a combination of two environmental friendly methods of fungus gnat control could lead to synergistic effects, which may provide novel approaches to economic and environmentally sustainable pest management measures.

13.
Mol Cell Proteomics ; 18(3): 448-460, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30523211

RESUMO

The recent accomplishment of comprehensive proteogenomic analysis of high-grade serous ovarian carcinoma (HGSOC) tissues reveals cancer associated molecular alterations were not limited to variations among DNA, and mRNA/protein expression, but are a result of complex reprogramming of signaling pathways/networks mediated by the protein and post-translational modification (PTM) interactomes. A systematic, multiplexed approach interrogating enzyme-substrate relationships in the context of PTMs is fundamental in understanding the dynamics of these pathways, regulation of cellular processes, and their roles in disease processes. Here, as part of Clinical Proteomic Tumor Analysis Consortium (CPTAC) project, we established a multiplexed PTM assay (tyrosine phosphorylation, and lysine acetylation, ubiquitylation and SUMOylation) method to identify protein probes' PTMs on the human proteome array. Further, we focused on the tyrosine phosphorylation and identified 19 kinases are potentially responsible for the dysregulated signaling pathways observed in HGSOC. Additionally, elevated kinase activity was observed when 14 ovarian cancer cell lines or tumor tissues were subjected to test the autophosphorylation status of PTK2 (pY397) and PTK2B (pY402) as a proxy for kinase activity. Taken together, this report demonstrates that PTM signatures based on lysate reactions on human proteome array is a powerful, unbiased approach to identify dysregulated PTM pathways in tumors.


Assuntos
Cistadenocarcinoma Seroso/metabolismo , Neoplasias Ovarianas/metabolismo , Proteínas Tirosina Quinases/metabolismo , Proteômica/métodos , Tirosina/metabolismo , Acetilação , Linhagem Celular Tumoral , Feminino , Quinase 1 de Adesão Focal/metabolismo , Quinase 2 de Adesão Focal/metabolismo , Humanos , Lisina/metabolismo , Fosforilação , Processamento de Proteína Pós-Traducional , Sumoilação , Ubiquitinação
14.
Elife ; 62017 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-28553926

RESUMO

Altered DNA methylation status is associated with human diseases and cancer; however, the underlying molecular mechanisms remain elusive. We previously identified many human transcription factors, including Krüppel-like factor 4 (KLF4), as sequence-specific DNA methylation readers that preferentially recognize methylated CpG (mCpG), here we report the biological function of mCpG-dependent gene regulation by KLF4 in glioblastoma cells. We show that KLF4 promotes cell adhesion, migration, and morphological changes, all of which are abolished by R458A mutation. Surprisingly, 116 genes are directly activated via mCpG-dependent KLF4 binding activity. In-depth mechanistic studies reveal that recruitment of KLF4 to the methylated cis-regulatory elements of these genes result in chromatin remodeling and transcription activation. Our study demonstrates a new paradigm of DNA methylation-mediated gene activation and chromatin remodeling, and provides a general framework to dissect the biological functions of DNA methylation readers and effectors.


Assuntos
Movimento Celular , Metilação de DNA , Regulação da Expressão Gênica , Fatores de Transcrição Kruppel-Like/metabolismo , Sequências Reguladoras de Ácido Nucleico , Ativação Transcricional , Linhagem Celular Tumoral , Montagem e Desmontagem da Cromatina , Humanos , Fator 4 Semelhante a Kruppel , Ligação Proteica
15.
PLoS One ; 11(6): e0157086, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27276213

RESUMO

Calcium channel subunits, including CACNA1C, have been associated with multiple psychiatric disorders. Specifically, genome wide association studies (GWAS) have repeatedly identified the single nucleotide polymorphism (SNP) rs1006737 in intron 3 of CACNA1C to be strongly associated with schizophrenia and bipolar disorder. Here, we show that rs1006737 marks a quantitative trait locus for CACNA1C transcript levels. We test 16 SNPs in high linkage disequilibrium with rs1007637 and find one, rs4765905, consistently showing allele-dependent regulatory function in reporter assays. We find allele-specific protein binding for 13 SNPs including rs4765905. Using protein microarrays, we identify several proteins binding ≥3 SNPs, but not control sequences, suggesting possible functional interactions and combinatorial haplotype effects. Finally, using circular chromatin conformation capture, we show interaction of the disease-associated region including the 16 SNPs with the CACNA1C promoter and other potential regulatory regions. Our results elucidate the pathogenic relevance of one of the best-supported risk loci for schizophrenia and bipolar disorder.


Assuntos
Canais de Cálcio Tipo L , Desequilíbrio de Ligação , Polimorfismo de Nucleotídeo Único , Regiões Promotoras Genéticas , Esquizofrenia , Transcrição Gênica , Adulto , Transtorno Bipolar/metabolismo , Canais de Cálcio Tipo L/biossíntese , Canais de Cálcio Tipo L/química , Canais de Cálcio Tipo L/genética , Feminino , Células HEK293 , Humanos , Íntrons , Masculino , Pessoa de Meia-Idade , Análise Serial de Proteínas , Estrutura Secundária de Proteína , Esquizofrenia/genética , Esquizofrenia/metabolismo
16.
Mol Cell ; 61(1): 153-60, 2016 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-26711009

RESUMO

Lin28, a well-known RNA-binding protein, regulates diverse cellular properties. All physiological functions of Lin28A characterized so far have been attributed to its repression of let-7 miRNA biogenesis or modulation of mRNA translational efficiency. Here we show that Lin28A directly binds to a consensus DNA sequence in vitro and in mouse embryonic stem cells in vivo. ChIP-seq and RNA-seq reveal enrichment of Lin28A binding around transcription start sites and a positive correlation between its genomic occupancy and expression of many associated genes. Mechanistically, Lin28A recruits 5-methylcytosine-dioxygenase Tet1 to genomic binding sites to orchestrate 5-methylcytosine and 5-hydroxymethylcytosine dynamics. Either Lin28A or Tet1 knockdown leads to dysregulated DNA methylation and expression of common target genes. These results reveal a surprising role for Lin28A in transcriptional regulation via epigenetic DNA modifications and have implications for understanding mechanisms underlying versatile functions of Lin28A in mammalian systems.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Células-Tronco Embrionárias/metabolismo , Regulação da Expressão Gênica , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas/metabolismo , Proteínas de Ligação a RNA/metabolismo , Ativação Transcricional , Animais , Sítios de Ligação , Linhagem Celular , Metilação de DNA , Proteínas de Ligação a DNA/genética , Epigênese Genética , Camundongos , Proteínas Proto-Oncogênicas/genética , Interferência de RNA , Proteínas de Ligação a RNA/genética , Transfecção
17.
Elife ; 2: e00726, 2013 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-24015356

RESUMO

DNA methylation, especially CpG methylation at promoter regions, has been generally considered as a potent epigenetic modification that prohibits transcription factor (TF) recruitment, resulting in transcription suppression. Here, we used a protein microarray-based approach to systematically survey the entire human TF family and found numerous purified TFs with methylated CpG (mCpG)-dependent DNA-binding activities. Interestingly, some TFs exhibit specific binding activity to methylated and unmethylated DNA motifs of distinct sequences. To elucidate the underlying mechanism, we focused on Kruppel-like factor 4 (KLF4), and decoupled its mCpG- and CpG-binding activities via site-directed mutagenesis. Furthermore, KLF4 binds specific methylated or unmethylated motifs in human embryonic stem cells in vivo. Our study suggests that mCpG-dependent TF binding activity is a widespread phenomenon and provides a new framework to understand the role and mechanism of TFs in epigenetic regulation of gene transcription. DOI:http://dx.doi.org/10.7554/eLife.00726.001.


Assuntos
Metilação de DNA , Fatores de Transcrição/metabolismo , Sítios de Ligação , Ilhas de CpG , Humanos , Fator 4 Semelhante a Kruppel , Regiões Promotoras Genéticas
18.
Anal Chem ; 84(15): 6553-60, 2012 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-22789061

RESUMO

C-reactive protein (CRP) is an acute phase protein whose levels are increased in many disorders. Levels greater than 3 µg/mL serum have hitherto been considered to indicate pathology, but there is increasing interest in assessments between 0.1 and 10 µg/mL, which have been found to correlate with severity of risk for cardiovascular disease. We report herein the generation of both antibody and Affimer based impedance immunoassays for CRP that are substantially more sensitive than clinically utilized immunonephelometry and immunoturbidity assessments. Significant in this study is not only the use of a constrained peptide to detect a clinically important target but also that derived electrochemical impedance assays can be highly sensitive even with probes whose relatively weak (µM) affinities are not amenable to target detection by surface plasmon resonance (SPR). Key to this finding is acknowledging that receptive surfaces of comparatively low initial steric bulk and charge transfer resistance are especially primed to be highly responsive to target binding in electroanalytical assays of this type.


Assuntos
Proteína C-Reativa/análise , Imunoensaio , Ressonância de Plasmônio de Superfície , Anticorpos Imobilizados/química , Anticorpos Imobilizados/imunologia , Proteína C-Reativa/imunologia , Espectroscopia Dielétrica , Eletrodos , Ouro/química , Polietilenoglicóis/química , Análise Serial de Proteínas
19.
Protein Eng Des Sel ; 24(9): 751-63, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21616931

RESUMO

Constrained binding peptides (peptide aptamers) may serve as tools to explore protein conformations and disrupt protein-protein interactions. The quality of the protein scaffold, by which the binding peptide is constrained and presented, is of crucial importance. SQT (Stefin A Quadruple Mutant-Tracy) is our most recent development in the Stefin A-derived scaffold series. Stefin A naturally uses three surfaces to interact with its targets. SQT tolerates peptide insertions at all three positions. Peptide aptamers in the SQT scaffold can be expressed in bacterial, yeast and human cells, and displayed as a fusion to truncated pIII on phage. Peptides that bind to CDK2 can show improved binding in protein microarrays when presented by the SQT scaffold. Yeast two-hybrid libraries have been screened for binders to the POZ domain of BCL-6 and to a peptide derived from PBP2', specific to methicillin-resistant Staphylococcus aureus. Presentation of the Noxa BH3 helix by SQT allows specific interaction with Mcl-1 in human cells. Together, our results show that Stefin A-derived scaffolds, including SQT, can be used for a variety of applications in cellular and molecular biology. We will henceforth refer to Stefin A-derived engineered proteins as Scannins.


Assuntos
Aptâmeros de Peptídeos/química , Aptâmeros de Peptídeos/metabolismo , Cistatina A/química , Cistatina A/metabolismo , Engenharia de Proteínas/métodos , Sequência de Aminoácidos , Aptâmeros de Peptídeos/genética , Linhagem Celular Tumoral , Dicroísmo Circular , Quinase 2 Dependente de Ciclina/química , Quinase 2 Dependente de Ciclina/genética , Cistatina A/genética , Humanos , Dados de Sequência Molecular , Mutação , Análise Serial de Proteínas , Proteínas Proto-Oncogênicas c-bcl-2/química , Proteínas Proto-Oncogênicas c-bcl-2/genética , Alinhamento de Sequência , Relação Estrutura-Atividade , Técnicas do Sistema de Duplo-Híbrido
20.
Faraday Discuss ; 149: 79-92; discussion 137-57, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21413175

RESUMO

In the near future, personalised medicine and phase-0 trials will require that clinical practitioners move from the "one biomarker per disease" paradigm to the use of molecular signatures of disease for diagnosis and the prediction of a patient's response to treatment. These signatures will be composed of biomarkers specific to the disease, and will include over-expression of normal protein from a gene that does not carry a mutation; loss of expression of an essential protein; expression of a protein from a mutant gene; and metabolites whose levels are altered in disease. Surrogates for protein expression, such as alterations in the messenger RNA that encode for them, have already proved their value. The next challenge, then, in clinical biosensing is to enable the multiplexed detection of protein biomarkers, and perhaps the multiplexed detection of mixed biomarkers (metabolites, RNA and proteins) all in a single test. Given the plethora of available antibodies specific for biomarkers, why is this not already happening? We believe that the limitation lies in the nature of the antibody molecule itself, and especially the fact that antibodies have evolved to function in solution, while most diagnostic tests take place at a surface. We have accordingly turned to the design of alternative antibodies, and have identified a protein that appears to be unusually stable on surfaces. The new, non-antibody, scaffold protein is derived from human Stefin A, a natural inhibitor of the cathepsin family of proteases. We have engineered this protein so that it lacks natural binding partners, and introduced a series of new binding surfaces through randomisation or directed replacement of the surfaces used by Stefin A to bind to cathepsins. Our new probes show exquisite specificity and binding affinities comparable to antibodies, and can be used to probe biology in intact cells. More importantly, together and in collaboration with other groups in Chemistry or Engineering Departments, we have shown that these designer proteins can be used in optical detection of labelled target proteins from whole cell lysates in a highly multiplexed microarray format, as well as in label-free detection of unlabelled proteins using surface plasmon resonance, QCM, microcantilevers and using electrochemical assays on gold electrodes. We believe that the combination of optimised surface chemistry, robust and combinatorial designer biological probes and novel, robust and sensitive detection technologies will enable, in the near future, the introduction of multiplexed biomarker detection in the clinical setting, most likely in cancer where multiple biomarkers are known, but probes are still lacking.


Assuntos
Aptâmeros de Peptídeos/química , Biomarcadores/análise , Ressonância de Plasmônio de Superfície/métodos , Análise Serial de Tecidos/métodos , Humanos
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