RESUMO
Aging leads to an accumulation of cellular mutations and damage, increasing the risk of senescence, apoptosis, and malignant transformation. Cellular senescence, which is pivotal in aging, acts as both a guard against cellular transformation and as a check against cancer progression. It is marked by stable cell cycle arrest, widespread macromolecular changes, a pro-inflammatory profile, and altered gene expression. However, it remains to be determined whether these differing subsets of senescent cells result from unique intrinsic programs or are influenced by their environmental contexts. Multiple transcription regulators and chromatin modifiers contribute to these alterations. Special AT-rich sequence-binding protein 1 (SATB1) stands out as a crucial regulator in this process, orchestrating gene expression by structuring chromatin into loop domains and anchoring DNA elements. This review provides an overview of cellular senescence and delves into the role of SATB1 in senescence-related diseases. It highlights SATB1's potential in developing antiaging and anticancer strategies, potentially contributing to improved quality of life and addressing aging-related diseases.
Assuntos
Senescência Celular , Proteínas de Ligação à Região de Interação com a Matriz , Humanos , Senescência Celular/genética , Proteínas de Ligação à Região de Interação com a Matriz/metabolismo , Proteínas de Ligação à Região de Interação com a Matriz/genética , Envelhecimento/genética , Envelhecimento/patologia , Envelhecimento/metabolismo , Animais , Neoplasias/genética , Neoplasias/patologia , Neoplasias/metabolismo , Cromatina/metabolismo , Cromatina/genéticaRESUMO
IMPORTANCE: The type-I interferon (IFN-I) signaling pathway is the first line of antiviral innate immunity. It must be precisely regulated against virus-induced damage. The tightly regulated mechanisms of action of host genes in the antiviral innate immune signaling pathway are still worth studying. Here, we report a novel role of DLG1 in positively regulating the IκB kinase epsilon (IKKε)-mediated IFN-I signaling response against negative-stranded RNA virus replication, whereas the RNA virus inhibits the expression of DLG1 for immune escape. Importantly, the E3 ligase March2 interacts with and promotes K27-linked polyubiquitination of IKKε, and p62 is a cargo receptor that recognizes ubiquitinated IKKε for eventual autophagic degradation. Together, the current findings elucidate the role of DLG1 in the antiviral IFN-I signaling pathway and viral infection repression.
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Autofagia , Proteína 1 Homóloga a Discs-Large , Quinase I-kappa B , Imunidade Inata , Vírus de RNA de Sentido Negativo , Proteína Sequestossoma-1 , Viroses , Humanos , Proteína 1 Homóloga a Discs-Large/metabolismo , Quinase I-kappa B/metabolismo , Imunidade Inata/imunologia , Vírus de RNA de Sentido Negativo/crescimento & desenvolvimento , Vírus de RNA de Sentido Negativo/imunologia , Poliubiquitina/metabolismo , Proteína Sequestossoma-1/antagonistas & inibidores , Transdução de Sinais , Viroses/imunologia , Animais , Linhagem CelularRESUMO
Novel cathodic and anodic dual-emitting electrochemiluminescence (ECL) of Ru(bpy)32+ and α-keto acids system are studied for the first time. Based on their cathodic and anodic ECL intensity, α-keto acids including oxalate, glyoxylic acid, pyruvic acid, and phenylglyoxylic acid can be directly sensitively detected. The limits of detection (LOD) of oxalate, glyoxylic acid, pyruvic acid, and phenylglyoxylic acid are 31.25 nM, 23.26 µM, 36.36 µM, and 18.52 µM, respectively. Possible mechanism of ECL produced is also proposed. Electrochemical results show that the reduction of oxygen at the cathode to produce ·OH is a vital step for cathodic and anodic dual-emitting ECL. Furthermore, using the enhancement strategy of S2O82-/Ag+ as coreactant accelerators is proposed considering that decarboxylation of α-keto acids to produce acyl radical can be achieved via S2O82- or Ag+. Using the S2O82-/Ag+ enhancement strategy, the LOD of oxalate, glyoxylic acid, pyruvic acid, and phenylglyoxylic acid are improved and are 2.12 nM, 0.37 µM, 3.23 µM, and 0.28 µM, respectively. Coreactants of Ru(bpy)32+ with dual-emitting ECL are expanded, which includes additional substances with organic carboxylic acid characterized by the keto group in α-position. It also provides an effective way to enhance ECL and improve sensitivity. More importantly, cathodic and anodic dual-emitting ECL greatly improves the selectivity.
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In sexually reproducing organisms maintenance of germ stem cell immortality is fundamental for transmitting genetic material to future generations. While previous research has mainly considered intrinsic regulatory mechanisms in the germline, our recent study has found a direct contribution of somatic cells in preserving germline immortality via the somatically expressed endoribonuclease ENDU-2 in Caenorhabditis elegans. We have identified ENDU-2 as a secreted protein that can be taken up by the germline. Here, we discuss how ENDU-2 might uncouple its RNA-binding and RNA-cleavage activities to control gene expression via either an endoribonuclease dependent or an independent way. We also speculate on a possible functional conservation of its mammalian homologs in mediating cell-cell communication as well as its potential significance in understanding human pathogenesis such as cancer development.
Assuntos
Proteínas de Caenorhabditis elegans , Animais , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Endorribonucleases/genética , Células Germinativas , Humanos , Células-TroncoRESUMO
The epigenetic regulation mechanism of porcine skeletal muscle development relies on the openness of chromatin and is also precisely regulated by transcriptional machinery. However, fewer studies have exploited the temporal changes in gene expression and the landscape of accessible chromatin to reveal the underlying molecular mechanisms controlling muscle development. To address this, skeletal muscle biopsy samples were taken from Landrace pigs at days 0 (D0), 60 (D60), 120 (D120), and 180 (D180) after birth and were then analyzed using RNA-seq and ATAC-seq. The RNA-seq analysis identified 8554 effective differential genes, among which ACBD7, TMEM220, and ATP1A2 were identified as key genes related to the development of porcine skeletal muscle. Some potential cis-regulatory elements identified by ATAC-seq analysis contain binding sites for many transcription factors, including SP1 and EGR1, which are also the predicted transcription factors regulating the expression of ACBD7 genes. Moreover, the omics analyses revealed regulatory regions that become ectopically active after birth during porcine skeletal muscle development after birth and identified 151,245, 53,435, 30,494, and 40,911 peaks. The enriched functional elements are related to the cell cycle, muscle development, and lipid metabolism. In summary, comprehensive high-resolution gene expression maps were developed for the transcriptome and accessible chromatin during postnatal skeletal muscle development in pigs.
Assuntos
Cromatina , Transcriptoma , Animais , Suínos/genética , Cromatina/genética , Cromatina/metabolismo , Epigênese Genética , Fatores de Transcrição/metabolismo , Músculo Esquelético/metabolismo , Desenvolvimento Muscular/genéticaRESUMO
Fluorescent silver coordination polymer nanoparticles (Ag-TPA CPNs) were synthesized using a combination of terephthalic acid (TPA) and silver nitrate via an ultrarapid microwave-assisted strategy within 15 min. The Ag-TPA CPNs displayed a high fluorescent quantum yield (QY = 20.19%) and large Stokes shift (~200 nm), with two emission peaks at 490 nm and 520 nm under an excitation wavelength of 320 nm. A fluorescent "turn-off" method using fluorescent Ag-TPA CPNs was applied to detect the alkaline phosphatase (ALP) activity on the basis of the ALP-catalyzed hydrolysis of ascorbic acid 2-phosphate (AA2P) to ascorbic acid (AA), and the AA product triggered the reduction of Ag+ ions into silver nanoparticles. The fluorescent lifetime of Ag-TPA CPNs decreased from 3.93 ms to 3.80 ms after the addition of ALP, which suggests that this fluorescent "turn-off" detection of ALP activity is a dynamic quenching process. The fluorescent intensity had a linear relationship with the concentration of ALP in the range of 0.2-12 mU/mL (r = 0.991) and with a limit of detection (LOD) of 0.07 mU/mL. It showed high selectivity in ALP detection towards metal ions and amino acids, as well as other enzymes such as horseradish peroxidase, glucose oxidase, tyrosinase, trypsin, lysozyme, and superoxides. When it was applied for the fluorescent "turn-off" detection of ALP activity in serum samples, mean recovery levels ranging from 99.5% to 101.2% were obtained, with relative standard deviations (RSDs) lower than 4% accuracy. Therefore, it is an efficient and accurate tool for analyzing ALP levels in biosamples.
Assuntos
Fosfatase Alcalina , Nanopartículas Metálicas , Fosfatase Alcalina/metabolismo , Nanopartículas Metálicas/química , Polímeros , Micro-Ondas , Prata , Corantes Fluorescentes/química , Limite de DetecçãoRESUMO
OBJECTIVES: To explore the effect of polydatin on the proliferation and apoptosis of acute monocytic leukemia cell line THP-1 and the possible mechanism. METHODS: After THP-1 cells were treated with polydatin at gradient concentrations for 24 hours and 48 hours, their proliferation was determined by CCK-8 assay, and half maximal inhibitory concentration (IC50) was calculated. Logarithmically growing THP-1 cells were divided into two groups, a polydatin treatment group (treated with IC50 of polydatin) and a blank control group (treated without polydatin solution), and incubated for 48 hours. Cell apoptosis and cell cycle were measured by flow cytometry. The expression levels of PI3K, AKT, p-AKT, mTOR, p-mTOR, p70 S6K, and p-p70 S6K proteins were measured by Western blotting. RESULTS: After treatment with polydatin, the proliferation of THP-1 cells was strongly inhibited, and the IC50 at 48 hours was 1 800 µmol/L. After treatment with 1 800 µmol/L polydatin solution for 48 hours, the apoptosis rate of THP-1 cells increased significantly compared with the blank control group (P<0.05). The cell cycle was arrested in the G0/G1 and S phases, with a significantly increased proportion of cells in the G0/G1 phase and a significantly decreased proportion of cells in the S phase, as compared with the blank control group (P<0.05). The expression levels of PI3K, AKT, p-AKT, mTOR, p-mTOR, p70 S6K, and p-p70 S6K proteins decreased significantly compared with the blank control group (P<0.05). CONCLUSIONS: Polydatin can effectively inhibit the proliferation, block the cell cycle, and induce the apoptosis of THP-1 cells, which may be related to inhibition of the PI3K/AKT/mTOR signaling pathway.
Assuntos
Glucosídeos , Fosfatidilinositol 3-Quinases , Estilbenos , Apoptose , Linhagem Celular Tumoral , Proliferação de Células , Glucosídeos/farmacologia , Humanos , Proteínas Proto-Oncogênicas c-akt , Transdução de Sinais , Estilbenos/farmacologia , Células THP-1 , Serina-Treonina Quinases TORRESUMO
BACKGROUND: Cystic and alveolar echinococcosis caused by the tapeworms Echinococcus granulosus sensu stricto (s.s.) and E. multilocularis, respectively, are important zoonotic diseases. Protease inhibitors are crucial for the survival of both Echinococcus spp. Kunitz-type inhibitors play a regulatory role in the control of protease activity. In this study,we identified Kunitz-type domain protease inhibitors(KDPIs) present in the genomes of these two tapeworms and analyzed the gene sequences using computational, structural bioinformatics and phylogenetic approaches to evaluate the evolutionary relationships of these genes. Hi-seq transcriptome analysis showed that E. granulosus s.s. KDPIs were differentially expressed in the different developmental stages. We validated some of the genes expressed in adult worm, protoscolex and cyst germinal membrane of E. granulosus s.s. and E. multilocularis by quantitative PCR. RESULTS: A total of 19 genes from E. multilocularis and 23 genes from E. granulosus s.s. were predicted to be KDPIs with the most containing a single Kunitz-domain. A maximum likelihood method phylogenetic tree indicated that the E. granulosus s.s. and E. multilocularis Kunitz domain peptides were divided into three branches containing 9 clusters. The ratio of positively charged residues and neutral residues are different between E. multilocularis and E. granulosus s.s. KDPIs. We also found that E. multilocularis had higher percentage of sequences containing signal peptides (17/19, 89.47%) than that of E. granulosus s.s. (14/23, 60.87%). Transcript analysis showed all the E. granulosus s.s. KDPI genes were expressed differentially in four developmental stages of the worm. Transcription analysis showed that 9 KDPIs (including EG_07244,EGR_08716 and EGR_10096) were highly upregulated in adult worm, and 2 KDPIs (EG_09268 and EG_09490) were highly expressed in the cyst germinal membrane. Quantitative gene expression analysis(qPCR) of four genes confirmed the expression of these genes. EGR_08716 and its homologous gene (EmuJ_001137000) were highly and specifically expressed in adult worms of the two worms. CONCLUSIONS: A total 19 and 23 KDPIs were identified in the genomes of E. multilocularis and E. granulosus s.s. , respectively. The differential expression of these KDPIs in different stages may indicate their different roles in the different hosts. The difference in characterization of KDPIs may be associated with the different pathology of metacestode stage of these two parasites.
Assuntos
Echinococcus granulosus , Animais , Biologia Computacional , Echinococcus granulosus/genética , Filogenia , Inibidores de ProteasesRESUMO
BACKGROUND: Cystic echinococcosis (CE) is a life-threatening zoonosis caused by the larval form of Echinococcus granulosus tapeworm. Our previous study showed that an approved drug pyronaridine (PND) is highly effective against CE, both in vitro and in an animal model. To identify possible target genes, transcriptome analysis was performed with E. granulosus sensu stricto protoscoleces treated with PND. RESULTS: A total of 1,321 genes were differentially expressed in protoscoleces treated with PND, including 541 upregulated and 780 downregulated genes. Gene ontology and KEGG analyses revealed that the spliceosome, mitogen-activated protein kinase (MAPK) pathway and ATP-binding cassette (ABC) transporters were the top three enriched pathways. Western blot analysis showed that PND treatment resulted in a dose-dependent increase in protein expression levels of EgMKK1 (MKK3/6-like) and EgMKK2 (MEK1/2-like), two members of MAPK cascades. Interestingly, several heat shock protein (HSP) genes were greatly downregulated including stress-inducible HSPs and their constitutive cognates, and some of them belong to Echinococcus-specific expansion of HSP70. CONCLUSIONS: PND has a great impact on the spliceosome, MAPK pathway and ABC transporters, which may underline the mechanisms by which PND kills E. granulosus protoscoleces. In addition, PND downregulates HSPs expression, suggesting a close relationship between the drug and HSPs.
Assuntos
Equinococose , Echinococcus granulosus , Preparações Farmacêuticas , Animais , Equinococose/tratamento farmacológico , Equinococose/genética , Echinococcus granulosus/genética , Perfilação da Expressão Gênica , NaftiridinasRESUMO
Targeting and monitoring the dynamics of mitochondria are of great significance because mitochondria are involved in a variety of physiological and pathological processes. For achieving this purpose, highly sensitive, photostable, tolerance and specific fluorescent probe is necessary. To obtain a superior mitochondrial fluorescent probe, (4-distyreneanthracenoxybutyl) bis(triphenylphosphonium) bromide (DSA-TPP) with aggregation-induced emission (AIE) characteristic was designed and synthesized for mitochondrial targeting. DSA-TPP dots with high fluorescence quantum yield (Φ = 17.9) and small particle size (8 nm) can be easily prepared by self-assembly formation. DSA-TPP dots had the ability of lightning mitochondria in living cells with high brightness, superior photostability and strong tolerance to cell environment change.
Assuntos
Antracenos/química , Corantes Fluorescentes/química , Mitocôndrias/metabolismo , Nanopartículas/química , Compostos Organofosforados/química , Fluorescência , Células HeLa , Humanos , Microscopia Confocal/métodos , Água/químicaRESUMO
BACKGROUND: Preoperative prediction of early recurrence (ER) of hepatocellular carcinoma (HCC) plays a critical role in individualized risk stratification and further treatment guidance. PURPOSE: To investigate the role of radiomics analysis based on multiparametric MRI (mpMRI) for predicting ER in HCC after partial hepatectomy. STUDY TYPE: Retrospective. POPULATION: In all, 113 HCC patients (ER, n = 58 vs. non-ER, n = 55), divided into training (n = 78) and validation (n = 35) cohorts. FIELD STRENGTH/SEQUENCE: 1.5T or 3.0T, gradient-recalled-echo in-phase T1 -weighted imaging (I-T1 WI) and opposed-phase T1 WI (O-T1 WI), fast spin-echo T2 -weighted imaging (T2 WI), spin-echo planar diffusion-weighted imaging (DWI), and gradient-recalled-echo contrast-enhanced MRI (CE-MRI). ASSESSMENT: In all, 1146 radiomics features were extracted from each image sequence, and radiomics models based on each sequence and their combination were established via multivariate logistic regression analysis. The clinicopathologic-radiologic (CPR) model and the combined model integrating the radiomics score with the CPR risk factors were constructed. A nomogram based on the combined model was established. STATISTICAL TESTS: Receiver operating characteristic (ROC) curve analysis was used to evaluate the discriminative performance of each model. The potential clinical usefulness was evaluated by decision curve analysis (DCA). RESULTS: The radiomics model based on I-T1 WI, O-T1 WI, T2 WI, and CE-MRI sequences presented the best performance among all radiomics models with an area under the ROC curve (AUC) of 0.771 (95% confidence interval (CI): 0.598-0.894) in the validation cohort. The combined nomogram (AUC: 0.873; 95% CI: 0.756-0.989) outperformed the radiomics model and the CPR model (AUC: 0.742; 95% CI: 0.577-0.907). DCA demonstrated that the combined nomogram was clinically useful. DATA CONCLUSION: The mpMRI-based radiomics analysis has potential to predict ER of HCC patients after hepatectomy, which could enhance risk stratification and provide support for individualized treatment planning. EVIDENCE LEVEL: 4. TECHNICAL EFFICACY: Stage 4.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Imageamento por Ressonância Magnética Multiparamétrica , Carcinoma Hepatocelular/diagnóstico por imagem , Carcinoma Hepatocelular/cirurgia , Hepatectomia , Humanos , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/cirurgia , Imageamento por Ressonância Magnética , Estudos RetrospectivosRESUMO
BACKGROUND: To investigate long-chain noncoding TM4SF1-AS1 in gastric cancer (GC) tissues and cells. METHODS: TM4SF1-AS1 in 40 GC tissues and adjacent tissues was detected and compared using real-time fluorescence quantitative PCR (qRT-PCR). TM4SF1-AS1 in MKN28 and SGC7901 GC cells was downregulated using small interfering RNA (shRNA). The cells were grouped into an interference group (shTM4SF1-AS1 group) and a control group (shControl group). MTT and Transwell tests were applied to determine the proliferation and invasion of the cells in both groups, and flow cytometry was performed to assess the apoptosis rate in the two groups. Western blotting was performed to determine changes in key proteins in cells during the epithelial-to-mesenchymal transition (EMT) and in the TM4SF1 and PI3K-AKT signalling pathways in response to the downregulation of TM4SF1-AS1. RESULTS: The proliferation of MKN28 and SGC7901 in the shTM4SF1-AS1 group was significantly inhibited at 48 h and 72 h compared to that in the shControl group (all P < 0.05). In the shTM4SF1-AS1 group, the number of invaded MKN28 and SGC7901 cells was significantly lower than that in the shControl group (all P < 0.05). Apoptosis in the MKN28 and SGC7901 shTM4SF1-AS1 groups was significantly higher than that in the shControl group (all P < 0.05). Compared to those in the shControl group, levels of E-cadherin in EMT-related proteins were significantly elevated (P < 0.01), while levels of N-cadherin, Snail and Twist1 were significantly decreased (all P < 0.01). After silencing the expression of LncTM4SF1-AS1, the expression levels of TM4SF1 in the shTM4SF1-AS1 group were downregulated compared to those in the shControl group, and the p-PI3K and p-AKT proteins in the PI3K-AKT signalling pathway in the shTM4SF1-AS1 group were downregulated compared to those of the shControl group. CONCLUSIONS: TM4SF1-AS1 is upregulated in gastric cancer tissues and cells. Interfering with and downregulating its expression inhibit cancer cell proliferation, invasion and the EMT and promote apoptosis. The underlying mechanism for these effects is related to silencing the TM4SF1 and PI3K-AKT signalling pathways. TM4SF1-AS1 may be a potential therapeutic target for gastric cancer.
Assuntos
RNA Longo não Codificante , Neoplasias Gástricas , Antígenos de Superfície , Apoptose , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Transição Epitelial-Mesenquimal , Regulação Neoplásica da Expressão Gênica , Humanos , Proteínas de Neoplasias/genética , Fosfatidilinositol 3-Quinases/genética , Prognóstico , RNA Longo não Codificante/genética , Neoplasias Gástricas/genéticaRESUMO
Glycoproteins and their mimics are challenging to produce because of their large number of polysaccharide side chains that form a densely grafted protein-polysaccharide brush architecture. Herein a new approach to protein bioconjugate synthesis is demonstrated that can approach the functionalization densities of natural glycoproteins through oligosaccharide grafting. Global amino acid substitution is used to replace the methionine residues in a methionine-enriched elastin-like polypeptide with homopropargylglycine (HPG); the substitution was found to replace 93% of the 41 methionines in the protein sequence as well as broaden and increase the thermoresponsive transition. A series of saccharides were conjugated to the recombinant protein backbones through copper(I)-catalyzed alkyne-azide cycloaddition to determine reactivity trends, with 83-100% glycosylation of HPGs. Only an acetyl-protected sialyllactose moiety showed a lower level of 42% HPG glycosylation that is attributed to steric hindrance. The recombinant glycoproteins reproduced the key biofunctional properties of their natural counterparts such as viral inhibition and lectin binding.
Assuntos
Materiais Biomiméticos/química , Química Click , Cobre/química , Glicoproteínas/metabolismo , Substituição de Aminoácidos , Animais , Materiais Biomiméticos/farmacologia , Cães , Hemaglutinação/efeitos dos fármacos , Células Madin Darby de Rim CaninoRESUMO
Activation of the FOXO transcription factor DAF-16 by reduced insulin/IGF signaling (IIS) is considered to be beneficial in C. elegans due to its ability to extend lifespan and to enhance stress resistance. In the germline, cell-autonomous DAF-16 activity prevents stem cell proliferation, thus acting tumor-suppressive. In contrast, hypodermal DAF-16 causes a tumorous germline phenotype characterized by hyperproliferation of the germline stem cells and rupture of the adjacent basement membrane. Here we show that cross-talk between DAF-16 and the transforming growth factor ß (TGFß)/bone morphogenic protein (BMP) signaling pathway causes germline hyperplasia and results in disruption of the basement membrane. In addition to activating MADM/NRBP/hpo-11 gene alone, DAF-16 also directly interacts with both R-SMAD proteins SMA-2 and SMA-3 in the nucleus to regulate the expression of mTORC1 pathway. Knocking-down of BMP genes or each of the four target genes in the hypodermis was sufficient to inhibit germline proliferation, indicating a cell-non-autonomously controlled regulation of stem cell proliferation by somatic tissues. We propose the existence of two antagonistic DAF-16/FOXO functions, a cell-proliferative somatic and an anti-proliferative germline activity. Whereas germline hyperplasia under reduced IIS is inhibited by DAF-16 cell-autonomously, activation of somatic DAF-16 in the presence of active IIS promotes germline proliferation and eventually induces tumor-like germline growth. In summary, our results suggest a novel pathway crosstalk of DAF-16 and TGF-ß/BMP that can modulate mTORC1 at the transcriptional level to cause stem-cell hyperproliferation. Such cell-type specific differences may help explaining why human FOXO activity is considered to be tumor-suppressive in most contexts, but may become oncogenic, e.g. in chronic and acute myeloid leukemia.
Assuntos
Proteínas Morfogenéticas Ósseas/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Carcinogênese/genética , Fatores de Transcrição Forkhead/metabolismo , Complexos Multiproteicos/metabolismo , Células-Tronco/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Animais , Caenorhabditis elegans/citologia , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Membrana Celular/metabolismo , Proliferação de Células , Células Epidérmicas , Epiderme/metabolismo , Fatores de Transcrição Forkhead/genética , Regulação Neoplásica da Expressão Gênica , Alvo Mecanístico do Complexo 1 de Rapamicina , Ligação Proteica , Transdução de Sinais , Células-Tronco/fisiologiaRESUMO
Acquired resistance to cytotoxic antineoplastic agents is a major clinical challenge in tumor therapy; however, the mechanisms involved are still poorly understood. In this study, we show that knockdown of CtIP, a corepressor of CtBP, promotes cell proliferation and alleviates G2/M phase arrest in etoposide (Eto)-treated HCT116 cells. Although the expression of p21 and growth arrest and DNA damage inducible α (GADD45a), which are important targets of p53, was downregulated in CtIP-deficient HCT116 cells, p53 deletion did not affect G2/M arrest after Eto treatment. In addition, the phosphorylation levels of Ser317 and Ser345 in Chk1 and of Ser216 in CDC25C were lower in CtIP-deficient HCT116 cells than in control cells after Eto treatment. Our results indicate that CtIP may enhance cell sensitivity to Eto by promoting G2/M phase arrest, mainly through the ATR-Chk1-CDC25C pathway rather than the p53-p21/GADD45a pathway. The expression of CtIP may be a useful biomarker for predicting the drug sensitivity of colorectal cancer cells.
Assuntos
Endodesoxirribonucleases/metabolismo , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Proteína Supressora de Tumor p53/efeitos dos fármacos , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Proteínas de Ciclo Celular/efeitos dos fármacos , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Inibidor de Quinase Dependente de Ciclina p21/efeitos dos fármacos , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Dano ao DNA/efeitos dos fármacos , Etoposídeo/farmacologia , Células HCT116 , Humanos , Pontos de Checagem da Fase M do Ciclo Celular/efeitos dos fármacos , Proteína Supressora de Tumor p53/genéticaRESUMO
Enzyme immobilization is widely used for large-scale industrial applications. However, the weak absorption through physical methods limits the recovery ability. Here, affinity-binding immobilization of enzymes was explored using a silica-specific affinity peptide (SAP) as a fusion tag to intensify the binding force between the enzyme and mesoporous silica (MPS) carrier. D-amino acid oxidase (DAAO) of Rhodosporidium toruloides was used as a model enzyme. The optimal screened SAP (LPHWHPHSHLQP) was selected from a M13 phage display peptide library and fused to the C-terminal of DAAO to obtain fused DAAOs with one, two and three SAP tags, respectively. The activity of DAAO-SAP-MPS was superior comparing with DAAO-2SAP-MPS and DAAO-3SAP-MPS; meanwhile DAAO-SAP-MPS shows 36% higher activity than that of DAAO-MPS. Fusion with one SAP improved the thermal stability with a 10% activity increase for immobilized DAAO-SAP-MPS compared to that of DAAO-MPS at 50 °C for 3 h. Moreover, the activity recovery of immobilized DAAO-SAP-MPS was 25% higher in operation stability assessment after six-batch conversions of cephalosporin to glutaryl-7-amino cephalosporanic acid than that of DAAO-MPS.
Assuntos
Aminoácidos/metabolismo , D-Aminoácido Oxidase/metabolismo , Peptídeos/metabolismo , Cefalosporinas/metabolismo , D-Aminoácido Oxidase/genética , Dióxido de Silício/químicaRESUMO
A method is presented for electrochemiluminescent (ECL) detection of the food additive curcumin via an energy transfer strategy and by using luminol-doped silica nanoparticles (luminol-NPs). The ECL emission of the luminol-NPs (peaking at 425 nm) is reduced in the presence of curcumin due to spectral overlap. The assay can be performed within 1 min, response is linear in the 0.1 to 100 µM curcumin concentration range, and the limit of detection is 32 nM. The method is selective over many ions, adenosine triphosphate, ascorbic acid, cysteine and folic acid. It was successfully applied to the determination of curcumin in spiked human serum and urine. The average recoveries range from 99.0 to 102.6%. Graphical abstract Electrochemiluminescence (ECL) "turn-off" detection of curcumin at levels as low as 32 nM via energy transfer using luminol-doped silica nanoparticles. No hydrogen peroxide (H2O2) is used in ECL detection which makes the luminol-NPs ECL system more stable than the conventional luminol-H2O2 ECL system.
RESUMO
To better analyze the problem of abnormal neuromuscular coupling related to motor dysfunction for stroke patients, the functional coupling of the multichannel electromyography (EMG) were studied and the difference between stroke patients and healthy subjects were further analyzed to explore the pathological mechanism of motor dysfunction after stroke. Firstly, the cross-frequency coherence (CFC) analysis and non-negative matrix factorization (NMF) were combined to construct a CFC-NMF model to study the linear coupling relationship in bands and the nonlinear coupling characteristics in different frequency ratios during elbow flexion and extension movement. Furthermore, the significant coherent area and sum of cross-frequency coherence were respectively calculated to quantitatively describe the intermuscular linear and nonlinear coupling characteristics. The results showed that the linear coupling relationship between multichannel muscles was different in frequency bands and the overall coupling was stronger in low frequency band. The linear coupling strength of the stroke patients was lower than that of the healthy subjects in different frequency bands especially in beta and gamma bands. For the nonlinear coupling, the intermuscular coupling strength of stroke patients in different frequency ratios was significantly lower than that of the healthy subjects, and the coupling strength in the frequency ratio 1â¶2 was higher than that in the frequency ratio 1â¶3. This method can provide a theoretical basis for exploring the intermuscular coupling mechanism of patients with motor dysfunction.
Assuntos
Eletromiografia , Músculo Esquelético/fisiopatologia , Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral/fisiopatologia , Estudos de Casos e Controles , HumanosRESUMO
We proposed the deprotection-induced block copolymer self-assembly (DISA); that is, the deprotection of hydroxyl groups resulted in in situ self-assembly of glycopolymers. In the previous studies, block copolymers soluble in common organic solvents were employed as the starting material. In this paper, by using the protected glyco-block containing preassembled glycovesicles in water as the starting material, we moved forward and made two exceeding achievements. First, we have observed a deprotection-induced morphology transition triggered by alkali in water. The carbohydrate-carbohydrate interactions were considered to contribute to such a morphology transition during deprotection. Second, lipase was found to be an efficient enzymatic trigger in the sugar deprotection, which motivates the immune-application of this morphology transition process. When lipase and a model antigen, ovalbumin (OVA), were encapsulated inside the glycovesicles, the deprotection of sugars by lipase induced the transition of vesicles to micelles and the lipase and OVA were released accordingly. When glycovesicles were internalized by dentritic cells (DCs), the lipase from lysosomes efficiently induced the release of OVA and presentation of antigen to T cells. During the process, lysosomal lipase performed as a trigger on the deprotection of sugars and the release of protein without any other reagents. The significance of this design is that as a delivery vehicle, the protected glycovesicles not only avoided unnecessary immune activation but also worked with the released OVA together; that is, the glycovehicle successfully activated DCs and improved the presentation efficiency of T cells remarkably.
Assuntos
Preparações de Ação Retardada/química , Lipase/administração & dosagem , Ovalbumina/administração & dosagem , Polietilenoglicóis/química , Poliestirenos/química , Açúcares/química , Animais , Apresentação de Antígeno , Linhagem Celular , Células Dendríticas/imunologia , Lipase/química , Camundongos , Micelas , Modelos Moleculares , Ovalbumina/química , Ovalbumina/imunologia , Triticum/enzimologiaRESUMO
BACKGROUND: Amyloid deposition is a potential contributor to postoperative cognitive dysfunction. The authors hypothesized that 6-week global cortical amyloid burden, determined by F-florbetapir positron emission tomography, would be greater in those patients manifesting cognitive dysfunction at 6 weeks postoperatively. METHODS: Amyloid deposition was evaluated in cardiac surgical patients at 6 weeks (n = 40) and 1 yr (n = 12); neurocognitive function was assessed at baseline (n = 40), 6 weeks (n = 37), 1 yr (n = 13), and 3 yr (n = 9). The association of 6-week amyloid deposition with cognitive dysfunction was assessed by multivariable regression, accounting for age, years of education, and baseline cognition. Differences between the surgical cohort with cognitive deficit and the Alzheimer's Disease Neuroimaging Initiative cohorts (normal and early/late mild cognitive impairment) was assessed, adjusting for age, education, and apolipoprotein E4 genotype. RESULTS: The authors found that 6-week abnormal global cortical amyloid deposition was not associated with cognitive dysfunction (13 of 37, 35%) at 6 weeks postoperatively (median standard uptake value ratio [interquartile range]: cognitive dysfunction 0.92 [0.89 to 1.07] vs. 0.98 [0.93 to 1.05]; P = 0.455). In post hoc analyses, global cortical amyloid was also not associated with cognitive dysfunction at 1 or 3 yr postoperatively. Amyloid deposition at 6 weeks in the surgical cohort was not different from that in normal Alzheimer's Disease Neuroimaging Initiative subjects, but increased over 1 yr in many areas at a rate greater than in controls. CONCLUSIONS: In this study, postoperative cognitive dysfunction was not associated with 6-week cortical amyloid deposition. The relationship between cognitive dysfunction and regional amyloid burden and the rate of postoperative amyloid deposition merit further investigation.