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1.
Nucleic Acids Res ; 52(6): 3011-3030, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38227944

RESUMO

DNA replication is a major source of endogenous DNA damage in tumor cells and a key target of cellular response to genotoxic stress. DNA replication can be deregulated by oncoproteins, such as transcription factor MYC, aberrantly activated in many human cancers. MYC is stringently regulated by the ubiquitin system - for example, ubiquitination controls recruitment of the elongation factor PAF1c, instrumental in MYC activity. Curiously, a key MYC-targeting deubiquitinase USP28 also controls cellular response to DNA damage via the mediator protein 53BP1. USP28 forms stable dimers, but the biological role of USP28 dimerization is unknown. We show here that dimerization limits USP28 activity and restricts recruitment of PAF1c by MYC. Expression of monomeric USP28 stabilizes MYC and promotes PAF1c recruitment, leading to ectopic DNA synthesis and replication-associated DNA damage. USP28 dimerization is stimulated by 53BP1, which selectively binds USP28 dimers. Genotoxic stress diminishes 53BP1-USP28 interaction, promotes disassembly of USP28 dimers and stimulates PAF1c recruitment by MYC. This triggers firing of DNA replication origins during early response to genotoxins and exacerbates DNA damage. We propose that dimerization of USP28 prevents ectopic DNA replication at transcriptionally active chromatin to maintain genome stability.


Assuntos
Dano ao DNA , Humanos , Enzimas Desubiquitinantes/genética , DNA/metabolismo , Neoplasias , Ubiquitina Tiolesterase/genética , Ubiquitina Tiolesterase/metabolismo , Ubiquitinação
2.
Mol Cell ; 61(1): 54-67, 2016 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-26687678

RESUMO

MYC is an unstable protein, and its turnover is controlled by the ubiquitin system. Ubiquitination enhances MYC-dependent transactivation, but the underlying mechanism remains unresolved. Here we show that MYC proteasomal turnover is dispensable for loading of RNA polymerase II (RNAPII). In contrast, MYC turnover is essential for recruitment of TRRAP, histone acetylation, and binding of BRD4 and P-TEFb to target promoters, leading to phosphorylation of RNAPII and transcriptional elongation. In the absence of histone acetylation and P-TEFb recruitment, MYC associates with the PAF1 complex (PAF1C) through a conserved domain in the MYC amino terminus ("MYC box I"). Depletion of the PAF1C subunit CDC73 enhances expression of MYC target genes, suggesting that the MYC/PAF1C complex can inhibit transcription. Because several ubiquitin ligases bind to MYC via the same domain ("MYC box II") that interacts with TRRAP, we propose that degradation of MYC limits the accumulation of MYC/PAF1C complexes during transcriptional activation.


Assuntos
Proteínas Nucleares/metabolismo , Fosfoproteínas/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Elongação da Transcrição Genética , Proteínas Supressoras de Tumor/metabolismo , Ubiquitinação , Acetilação , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Sítios de Ligação , Proteínas de Ciclo Celular , Proliferação de Células , Montagem e Desmontagem da Cromatina , Células HEK293 , Células HeLa , Histonas/metabolismo , Humanos , Complexos Multiproteicos , Mutação , Proteínas Nucleares/genética , Fosfoproteínas/genética , Fator B de Elongação Transcricional Positiva/metabolismo , Regiões Promotoras Genéticas , Proteólise , Proteínas Proto-Oncogênicas c-myc/genética , Interferência de RNA , RNA Polimerase II/metabolismo , Fatores de Tempo , Fatores de Transcrição/metabolismo , Transfecção , Proteínas Supressoras de Tumor/genética
3.
Mediators Inflamm ; 2022: 5985143, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35784174

RESUMO

Studies have shown that electroacupuncture (EA) can effectively improve vascular cognitive impairment (VCI), but its mechanisms have not been clearly elucidated. This study is aimed at investigating the mechanisms underlying the effects of EA treatment on hippocampal synaptic transmission efficiency and plasticity in rats with VCI. Methods. Sprague-Dawley rats were subjected to VCI with bilateral common carotid occlusion (2VO). EA stimulation was applied to Baihui (GV20) and Shenting (GV24) acupoints for 30 min once a day, five times a week, for four weeks. Our study also included nonacupoint groups to confirm the specificity of EA therapy. The Morris water maze (MWM) was used to assess cognitive function. Electrophysiological techniques were used to detect the field characteristics of the hippocampal CA3-CA1 circuit in each group of rats, including input-output (I/O), paired-pulse facilitation ratios (PPR), field excitatory postsynaptic potential (fEPSP), and excitatory postsynaptic current (EPSC). The expression of synapse- and calcium-mediated signal transduction associated proteins was detected through western blotting. Results. The MWM behavioural results showed that EA significantly improved cognitive function in VCI model rats. EA increased the I/O curve of VCI model rats from 20 to 90 µA. No significant differences were observed in hippocampal PPR. The fEPSP of the hippocampal CA3-CA1 circuit was significantly increased after EA treatment compared with that after nonacupuncture treatment. We found that EA led to an increase in the EPSC amplitude and frequency, especially in the decay and rise times. In addition, the protein expression and phosphorylation levels of N-methyl-D-aspartate receptor 2B, α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor 1, and Ca2+-calmodulin-dependent protein kinase II increased to varying degrees in the hippocampus of VCI model rats. Conclusion. EA at GV20 and GV24 acupoints increased the basic synaptic transmission efficiency and synaptic plasticity of the hippocampal CA3-CA1 circuit, thereby improving learning and memory ability in rats with VCI.


Assuntos
Disfunção Cognitiva , Eletroacupuntura , Animais , Disfunção Cognitiva/terapia , Eletroacupuntura/métodos , Hipocampo/metabolismo , Ratos , Ratos Sprague-Dawley , Transmissão Sináptica
4.
Semin Cancer Biol ; 36: 62-70, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26459133

RESUMO

The F-box protein Fbw7 targets for degradation critical cellular regulators, thereby controlling essential processes in cellular homeostasis, including cell cycle, differentiation and apoptosis. Most Fbw7 substrates are strongly associated with tumorigenesis and Fbw7 can either suppress or promote tumor development in mouse models. Fbw7 activity is controlled at different levels, resulting in specific and tunable regulation of the abundance and activity of its substrates. Here we highlight recent studies on the role of Fbw7 in controlling tumorigenesis and on the mechanisms that modulate Fbw7 function.


Assuntos
Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Proteínas F-Box/genética , Proteínas F-Box/metabolismo , Neoplasias/etiologia , Neoplasias/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Animais , Proteínas de Ciclo Celular/química , Proteínas F-Box/química , Proteína 7 com Repetições F-Box-WD , Regulação Neoplásica da Expressão Gênica , Homeostase , Humanos , Terapia de Alvo Molecular , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Ligação Proteica , Multimerização Proteica , Transporte Proteico , Proteólise , Transdução de Sinais , Especificidade por Substrato , Ubiquitina-Proteína Ligases/química , Ubiquitinação
5.
J Ind Microbiol Biotechnol ; 41(3): 527-34, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24281395

RESUMO

Antimicrobial peptides (AMPs) have been paid considerable attention owing to their broad-spectrum antimicrobial activity and have great potential as novel antimicrobials. In this study, a novel hybrid peptide LF15-CA8 was designed on the basis of bovine lactoferricin (LfcinB) and cecropin A. The gene segment encoding LF15-CA8 was synthesized and cloned into pGEX-4T-BH to form pGEX-4T-LC1 containing one copy of the LF15-CA8 coding region. A series of recombinant vectors containing up to six multiple-copy LF15-CA8 coding regions, i.e., pGEX-4T-LCn (n = 1-6), were subsequently constructed, and used for transformation in Escherichia coli BL21(DE3). After induction with IPTG, pGEX-4T-LC1 and pGEX-4T-LC2 transformants successfully expressed fusion proteins GST-LF15-CA8 and GST-(LF15-CA8)2 in the form of inclusion bodies, respectively. The inclusion bodies were dissolved and the peptide was successfully released in 70 % formic acid in a single step. After purification, about 10.0 mg of the recombinant peptide LF15-CA8 with purity more than 97 % was obtained from 1 l of bacteria culture of pGEX-4T-LC2 transformants. LF15-CA8 caused an increase in antibacterial activity against Gram-positive bacterium (Staphylococcus aureus ATCC 25923) compared with the parent peptides and did not show obvious hemolytic activity against human erythrocytes in the range of effective antibacterial concentration. These results suggest that the peptide LF15-CA8 could be a promising candidate for therapeutic applications, and may lead to a cost-effective solution for the large-scale production of AMPs.


Assuntos
Antibacterianos/biossíntese , Peptídeos Catiônicos Antimicrobianos/biossíntese , Animais , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/genética , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bovinos , Escherichia coli/genética , Vetores Genéticos , Humanos , Lactoferrina/genética , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/farmacologia , Staphylococcus aureus/efeitos dos fármacos
6.
Phytother Res ; 28(2): 296-9, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23554049

RESUMO

Furanodiene (FUR) is a natural terpenoid isolated from Rhizoma Curcumae, a well-known Chinese medicinal herb that presents anti-proliferative activities in several cancer cell lines. Recently, we found that the combined treatment of FUR with paclitaxel (TAX) showed synergetic anti-proliferative activities in 95-D lung cancer cells. Herein, we showed that FUR reduced the cell numbers distributed in mitosis phase induced by TAX while increased those in G1 phase. The protein levels of cyclin D1, cyclin B1, CDK6 and c-Myc were all down-regulated in the group of combined treatment. The dramatically down-regulated expression of integrin ß4, focal adhesion kinase and paxillin might partially contribute to the synergic effect. Though FUR alone obviously induced endoplasmic reticulum stress, this signaling pathway may not contribute to the synergetic anti-proliferative effect as the protein expression of CHOP and BIP was similar in FUR alone and combined treatment group.


Assuntos
Ciclo Celular/efeitos dos fármacos , Furanos/farmacologia , Compostos Heterocíclicos com 2 Anéis/farmacologia , Integrina beta4/metabolismo , Neoplasias Pulmonares/metabolismo , Paclitaxel/farmacologia , Transdução de Sinais/efeitos dos fármacos , Linhagem Celular Tumoral , Curcuma/química , Ciclina B1/metabolismo , Ciclina D1/metabolismo , Quinase 6 Dependente de Ciclina/metabolismo , Sinergismo Farmacológico , Medicamentos de Ervas Chinesas/farmacologia , Estresse do Retículo Endoplasmático , Quinase 1 de Adesão Focal/metabolismo , Humanos , Paxilina/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo
7.
CNS Neurosci Ther ; 30(5): e14743, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38780008

RESUMO

AIMS: Nerve growth factor (NGF) loss is a potential factor for the degeneration of basal forebrain cholinergic neurons (BFCNs) in Alzheimer's disease (AD), and Rab5a is a key regulatory molecule of NGF signaling transduction. Here, we investigated the changes of Rab5a in 5 × FAD mice and further explored the mechanism of Electroacupuncture (EA) treatment in improving cognition in the early stage of AD. METHODS: The total Rab5a and Rab5a-GTP in 5-month-old 5 × FAD mice and wild-type mice were detected using WB and IP technologies. 5 × FAD mice were treated with EA at the Bai hui (DU20) and Shen ting (DU24) acupoints for 4 weeks and CRE/LOXP technology was used to confirm the role of Rab5a in AD mediated by EA stimulation. The Novel Object Recognition and Morris water maze tests were used to evaluate the cognitive function of 5 × FAD mice. The Nissl, immunohistochemistry, and Thioflavin S staining were used to observe pathological morphological changes in the basal forebrain circuit. The Golgi staining was used to investigate the synaptic plasticity of the basal forebrain circuit and WB technology was used to detect the expression levels of cholinergic-related and NGF signal-related proteins. RESULTS: The total Rab5a was unaltered, but Rab5a-GTP increased and the rab5a-positive early endosomes appeared enlarged in the hippocampus of 5 × FAD mice. Notably, EA reduced Rab5a-GTP in the hippocampus in the early stage of 5 × FAD mice. EA could improve object recognition memory and spatial learning memory by reducing Rab5a activity in the early stage of 5 × FAD mice. Moreover, EA could reduce Rab5a activity to increase NGF transduction and increase the levels of phosphorylated TrkA, AKT, and ERK in the basal forebrain and hippocampus, and increase the expression of cholinergic-related proteins, such as ChAT, vAchT, ChT1, m1AchR, and m2AchR in the basal forebrain and ChAT, m1AchR, and m2AchR in the hippocampus, improving synaptic plasticity in the basal forebrain hippocampal circuit in the early stage of 5 × FAD mice. CONCLUSIONS: Rab5a hyperactivation is an early pathological manifestation of 5 × FAD mice. EA could suppress Rab5a-GTP to promote the transduction of NGF signaling, and enhance the synaptic plasticity of the basal forebrain hippocampal circuit improving cognitive impairment in the early stage of 5 × FAD mice.


Assuntos
Doença de Alzheimer , Eletroacupuntura , Camundongos Transgênicos , Fator de Crescimento Neural , Proteínas rab5 de Ligação ao GTP , Animais , Proteínas rab5 de Ligação ao GTP/metabolismo , Fator de Crescimento Neural/metabolismo , Camundongos , Eletroacupuntura/métodos , Doença de Alzheimer/terapia , Doença de Alzheimer/metabolismo , Transdução de Sinais/fisiologia , Masculino , Memória/fisiologia , Aprendizagem/fisiologia , Aprendizagem em Labirinto/fisiologia , Camundongos Endogâmicos C57BL , Plasticidade Neuronal/fisiologia
8.
Adv Mater ; : e2404815, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38719211

RESUMO

The solid electrolyte interphase (SEI) with lithium fluoride (LiF) is critical to the performance of lithium metal batteries (LMBs) due to its high stability and mechanical properties. However, the low Li ion conductivity of LiF impedes the rapid diffusion of Li ions in the SEI, which leads to localized Li ion oversaturation dendritic deposition and hinders the practical applications of LMBs at high-current regions (>3 C). To address this issue, a fluorophosphated SEI rich with fast ion-diffusing inorganic grain boundaries (LiF/Li3P) is introduced. By utilizing a sol electrolyte that contains highly dispersed porous LiF nanoparticles modified with phosphorus-containing functional groups, a fluorophosphated SEI is constructed and the presence of electrochemically active Li within these fast ion-diffusing grain boundaries (GBs-Li) that are non-nucleated is demonstrated, ensuring the stability of the Li || NCM811 cell for over 1000 cycles at fast-charging rates of 5 C (11 mA cm-2). Additionally, a practical, long cycling, and intrinsically safe LMB pouch cell with high energy density (400 Wh kg-1) is fabricated. The work reveals how SEI components and structure design can enable fast-charging LMBs.

9.
Medicine (Baltimore) ; 102(19): e33799, 2023 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-37171313

RESUMO

BACKGROUND: Anastomotic stenosis is a common complication of colorectal surgery with anastomosis. To explore a minimally invasive novel approach surgical method for the treatment of rectal anastomotic strictures using transurethral prostate resection instrumentation. METHODS: From 2012 to 2022, 18 patients for the treatment of rectal anastomotic strictures using transurethral prostate resection instrumentation. The transurethral prostate resection instrumentation enters the rectum through the anus to incise the narrow anastomotic orifice in a 4-point radial manner under the resectoscope. RESULTS: The surgery was successfully completed in 18 patients, and there were no postoperative complications. Postoperatively, 12 patients achieved satisfactory improvement in defecation after 1 incision, and 4 patients underwent another incision 3 months later. Two patients underwent incisions thrice, and the ease of defecation improved in a short period; however, they later underwent permanent colostomy due to repeated stenosis and pain. CONCLUSION: The transanal 4-point radial incision of the prostate using transurethral prostate resection instrumentation is a minimally invasive, safe, effective, and simple surgical method for the treatment of rectal anastomotic stenosis supplemented by postoperative dilatation, and is worthy of clinical application.


Assuntos
Neoplasias Retais , Ressecção Transuretral da Próstata , Masculino , Humanos , Neoplasias Retais/cirurgia , Constrição Patológica/etiologia , Constrição Patológica/cirurgia , Ressecção Transuretral da Próstata/efeitos adversos , Reto/cirurgia , Anastomose Cirúrgica/efeitos adversos
10.
Front Genet ; 14: 1108440, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37035742

RESUMO

Purpose: To establish an effective genomic diagnosis pipeline for children with autism spectrum disorder (ASD) for its genetic etiology and intervention. Methods: A cohort of 354 autism spectrum disorder patients were obtained from Beijing Children's Hospital, Capital Medical University. Peripheral blood samples of the patients were collected for whole genome sequencing (WGS) and RNA sequencing (RNAseq). Sequencing data analyses were performed for mining the single nucleotide variation (SNV), copy number variation (CNV) and structural variation (SV). Sanger sequencing and quantitative PCR were used to verify the positive results. Results: Among 354 patients, 9 cases with pathogenic/likely pathogenic copy number variation and 10 cases with pathogenic/likely pathogenic single nucleotide variations were detected, with a total positive rate of 5.3%. Among these 9 copy number variation cases, 5 were de novo and 4 were inherited. Among the 10 de novo single nucleotide variations, 7 were previously unreported. The pathological de novo mutations account for 4.2% in our cohort. Conclusion: Rare mutations of copy number variations and single nucleotide variations account for a relatively small proportion of autism spectrum disorder children, which can be easily detected by a genomic testing pipeline of combined whole genome sequencing and RNA sequencing. This is important for early etiological diagnosis and precise management of autism spectrum disorder with rare mutations.

11.
Appl Microbiol Biotechnol ; 95(5): 1191-8, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22189867

RESUMO

With great therapeutic potential against antibiotic-resistant bacteria, viruses, and even parasites, antimicrobial peptides (AMPs) have received increased interest as pharmaceutical agents in recent years. It is a worthy yet challenging work to carry out the implement and improvement of AMPs production using bioengineering techniques. In the present study, a novel hybrid peptide LFT33 was designed derived from LfcinB and thanatin. The cDNA fragment encoding LFT33 with preferred codons of Escherichia coli was chemically synthesized and ligated into the vector pET32a(+) to express the LFT33 fusion protein. The fusion protein was successfully expressed in soluble form in E. coli induced under optimized conditions. After purification by affinity chromatography, the fusion protein was cleaved successfully by enterokinase and released the peptide LFT33. About 0.5 mg of the recombinant LFT33 was obtained by reversed-phase high performance liquid chromatography from 1 l of culture medium. Mass spectrometry analysis of the purified recombinant LFT33 demonstrated that the molecular weight perfectly matched the calculated mass (4,195 Da). The recombinant peptide LFT33 caused an increase in antimicrobial activity (IC(50) = 16-64 µg/ml) against given strains and did not show hemolytic activity for human erythrocytes. The results indicated that the hybrid peptide LFT33 could serve as a promising candidate for pharmaceutical agents.


Assuntos
Peptídeos Catiônicos Antimicrobianos/isolamento & purificação , Peptídeos Catiônicos Antimicrobianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/genética , Bactérias/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Cromatografia de Afinidade , Cromatografia Líquida de Alta Pressão , Eritrócitos/efeitos dos fármacos , Escherichia coli/genética , Expressão Gênica , Vetores Genéticos , Concentração Inibidora 50 , Espectrometria de Massas , Peso Molecular , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas Recombinantes de Fusão/farmacologia
12.
Artigo em Inglês | MEDLINE | ID: mdl-22927878

RESUMO

Furanodiene (FUR) is a natural terpenoid isolated from Curcumae Rhizoma, a well-known Chinese medicinal herb that presents antiproliferation activities in several cancer cell lines. In this study, we demonstrated that FUR concentration dependently inhibits the cell proliferation of A549, NIH-H1299, and 95-D lung cancer cells. ß-elemene, another terpenoid isolated from Curcumae Rhizoma, exhibited weaker antiproliferative effects in A549 and NIH-H1299 cells and activities similar to FUR in 95-D cells. FUR significantly inhibited colony formation in A549 and 95-D cells and upregulated both the mRNA and protein expression levels of binding immunoglobulin protein (BIP) and C/EBP homologous protein (CHOP), indicating that endoplasmic reticulum (ER) stress is induced. FUR treatment led to the accumulation of CHOP in the nucleus, which further confirms induction of ER stress. Furthermore, combined treatment of FUR with paclitaxel showed significant synergetic activities in NIH-H1299 and 95-D cells, suggesting its potential roles in combination therapy. These findings provide a basis for the further study of the anticancer effects in vivo and the internal mechanisms of FUR.

13.
Yao Xue Xue Bao ; 47(11): 1423-7, 2012 Nov.
Artigo em Zh | MEDLINE | ID: mdl-23387071

RESUMO

Natural product is an important source of new drug research and development (R&D). Traditional Chinese medicine (TCM) innovation is the key step for its modernization and internationalization. However, due to the complexity of TCM, there are many difficulties and confusions in this process. Target-based drug discovery is the mainstream model and method of R&D. TTD, short for therapeutic target database, is developed by National University of Singapore. Besides a large amount of information on drug targets, the database also contains considerable information related to natural products. This paper briefly introduces the TTD, analyzes the natural products derived drugs/compounds recorded in TTD, which we think might provide some inspiration for the innovation of TCM.


Assuntos
Bases de Dados Factuais , Sistemas de Liberação de Medicamentos , Descoberta de Drogas , Medicamentos de Ervas Chinesas , Medicina Tradicional Chinesa , Singapura
14.
J Cancer ; 13(5): 1679-1684, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35371320

RESUMO

Purpose: To explore a minimally invasive emergency solution for acute obstruction caused by rectal cancer in patients in whom rectal stents or drainage tubes cannot be placed under the guidance of conventional colonoscopy or digital subtraction angiography (DSA). Patients and Methods: Without anesthesia, analgesia, or sedation, the prostate resection endoscopy was inserted into the rectum through the anus, and the rectal space in which the tumor caused obstruction was searched with a certain flushing pressure until it crossed the area of obstruction to reach the proximal intestinal cavity. The drainage catheter or rectal stent was inserted through the sheath of the endoscope to relieve the acute obstruction and permit further cancer treatment. Results: In 31 patients in whom a drainage catheter or rectal stent could not be inserted using conventional colonoscopy or DSA guidance, placement of the catheter or stent into the proximal intestinal cavity was achieved in 28 patients, including drainage tube placement in 21 patients and rectal stent placement in seven patients. Three patients could not undergo placement because of their advanced age and poor general condition. The operative time ranged 15-40 min. Among the 28 patients whose obstruction was relieved, 23 patients underwent radical resection rectal cancer after 10-14 days, and five patients were discharged with stents because they were unwilling to receive further treatment. There were no postoperative complications. Conclusion: Transanal resection is a minimally invasive, effective, safe, and feasible emergency treatment for rectal cancer-associated obstruction.

15.
Adv Mater ; 33(42): e2102134, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34480366

RESUMO

Electrolyte engineering via fluorinated additives is promising to improve cycling stability and safety of high-energy Li-metal batteries. Here, an electrolyte is reported in a porous lithium fluoride (LiF) strategy to enable efficient carbonate electrolyte engineering for stable and safe Li-metal batteries. Unlike traditionally engineered electrolytes, the prepared electrolyte in the porous LiF nanobox exhibits nonflammability and high electrochemical performance owing to strong interactions between the electrolyte solvent molecules and numerous exposed active LiF (111) crystal planes. Via cryogenic transmission electron microscopy and X-ray photoelectron spectroscopy depth analysis, it is revealed that the electrolyte in active porous LiF nanobox involves the formation of a high-fluorine-content (>30%) solid electrolyte interphase layer, which enables very stable Li-metal anode cycling over one thousand cycles under high current density (4 mA cm-2 ). More importantly, employing the porous LiF nanobox engineered electrolyte, a Li || LiNi0.8 Co0.1 Mn0.1 O2 pouch cell is achieved with a specific energy of 380 Wh kg-1 for stable cycling over 80 cycles, representing the excellent performance of the Li-metal pouch cell using practical carbonate electrolyte. This study provides a new electrolyte engineering strategy for stable and safe Li-metal batteries.

16.
Elife ; 62017 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-28193319

RESUMO

The human ubiquitin ligase HUWE1 has key roles in tumorigenesis, yet it is unkown how its activity is regulated. We present the crystal structure of a C-terminal part of HUWE1, including the catalytic domain, and reveal an asymmetric auto-inhibited dimer. We show that HUWE1 dimerizes in solution and self-associates in cells, and that both occurs through the crystallographic dimer interface. We demonstrate that HUWE1 is inhibited in cells and that it can be activated by disruption of the dimer interface. We identify a conserved segment in HUWE1 that counteracts dimer formation by associating with the dimerization region intramolecularly. Our studies reveal, intriguingly, that the tumor suppressor p14ARF binds to this segment and may thus shift the conformational equilibrium of HUWE1 toward the inactive state. We propose a model, in which the activity of HUWE1 underlies conformational control in response to physiological cues-a mechanism that may be exploited for cancer therapy.


Assuntos
Multimerização Proteica , Ubiquitina-Proteína Ligases/química , Ubiquitina-Proteína Ligases/metabolismo , Cristalografia por Raios X , Humanos , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Proteína Supressora de Tumor p14ARF/metabolismo , Proteínas Supressoras de Tumor
17.
Sci China Life Sci ; 60(7): 739-745, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28624958

RESUMO

Bardet-Biedl syndrome (BBS) is a genetically heterogeneous disorder characterized by retinal dystrophy, polydactyly, obesity, developmental delay, and renal defects. At least 21 candidate BBS-associated genes (BBS1-19, NPHP1, and IFT172) have previously been identified, and all of them play important roles in ciliary function. Here, we collected a BBS pedigree with four members and performed whole-exome sequencing on the proband. The variants were analyzed and evaluated to confirm their pathogenicity. We found compound heterozygous variants (c.1192C>T, p.Q398* and c.1175C>T, p.T392M) in MKKS in both the siblings, and these were likely to be pathogenic variants. We also found a missense variant (c.2029G>C, p.E677Q) in NPHP1 and a missense variant (c.2470C>T, p.R824C) in BBS9 in the proband only, which are variants of uncertain significance. The compound heterozygous variants were probably responsible for the BBS phenotype in this Chinese pedigree and the missense mutations in NPHP1 and BBS9 might contribute to the mutation load.


Assuntos
Síndrome de Bardet-Biedl/genética , Exoma , Chaperoninas do Grupo II/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Criança , Proteínas do Citoesqueleto , Feminino , Heterozigoto , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Proteínas de Membrana/genética , Proteínas de Neoplasias/genética , Linhagem , Polimorfismo de Nucleotídeo Único
18.
Mol Cell Oncol ; 2(3): e995041, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-27308481

RESUMO

The Usp28 deubiquitinase antagonizes Fbw7-mediated turnover of multiple oncoproteins, including Myc, Jun, and Notch, and promotes tumorigenesis in the intestine. Our recent study reveals that Usp28 also counteracts autocatalytic ubiquitination of Fbw7, suggesting a complex role for Usp28 in the regulation of Fbw7 activity and tumor development.

19.
Biotechnol Prog ; 31(2): 369-74, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25641948

RESUMO

The antimicrobial peptide fowlicidin-2 identified in chicken is a member of the cathelicidins family. The mature fowlicidin-2 possesses high antibacterial efficacy and lipopolysaccharide (LPS) neutralizing activity, and also represents an excellent candidate as an antimicrobial agent. In the present study, the recombinant fowlicidin-2 was successfully produced by Escherichia coli (E. coli) recombinant expression system. The gene encoding fowlicidin-2 with the codon preference of E. coli was designed through codon optimization and synthesized in vitro. The gene was then ligated into the plasmid pET-32a(+), which features fusion protein thioredoxin at the N-terminal. The recombinant plasmid was transformed into E. coli BL21(DE3) and cultured in Luria-Bertani (LB) medium. After isopropyl-ß-D-thiogalactopyranoside (IPTG) induction, the fowlicidin-2 fusion protein was successfully expressed as inclusion bodies. The inclusion bodies were dissolved and successfully released the peptide in 70% formic acid solution containing cyanogen bromide (CNBr) in a single step. After purification by reverse-phase high-performance liquid chromatography (RP-HPLC), ∼6.0 mg of fowlicidin-2 with purity more than 97% was obtained from 1 litre of bacteria culture. The recombinant peptide exhibited high antibacterial activity against the Gram-positive and Gram-negative bacteria, and even drug-resistant strains. This system could be used to rapidly and efficiently produce milligram quantities of a battery of recombinant antimicrobial peptides as well as for large-scale production.


Assuntos
Peptídeos Catiônicos Antimicrobianos/metabolismo , Escherichia coli/genética , Proteínas Recombinantes de Fusão/metabolismo , Animais , Antibacterianos/química , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/genética , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bactérias/efeitos dos fármacos , Galinhas , Corpos de Inclusão/química , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/farmacologia
20.
Eur J Pharmacol ; 749: 81-8, 2015 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-25592318

RESUMO

Platycodin D (PD), isolated from the Chinese medicinal herb named Platycodonis Radix, is a triterpenoid saponin with well-known anti-tumor effects. In this study, we provided reliable evidence that PD triggered autophagy in a number of cell lines in vitro. PD-triggered autophagy was identified by observation of cytoplasmic vacuole, up-regulation of microtubule-associated protein 1 light chain 3 II (LC3-II), and accumulation of autophagosomes. The Akt/mammalian target of rapamycin (mTOR) pathway may be not involved in PD-triggered autophagy, as evidenced by the increased phosphorylation of Akt (Thr308), mTOR (Ser2448), ribosomal protein S6 kinase (Ser371), and ULK1 (Ser757). However, the extracellular signal-regulated kinase (ERK) was activated after PD treatment. The decreased ERK phosphorylation caused by pretreatment with U0126, an inhibitor of MEK, suppressed the expression of LC3-II compared with PD treatment alone, suggesting that ERK pathway may have a critical function in PD-triggered autophagy. In addition, the PD-induced proliferative inhibition and apoptosis were enhanced when pretreatment with autophagy inhibitor chloroquine (CQ) or bafilomycin A1 (BAF), indicating that PD may trigger a protective autophagy in HepG2 cells. To the best of our knowledge, this paper is the first to report that PD triggers autophagy in a series of cell lines and ERK activation is important for PD-triggered autophagy in hepatocellular carcinoma HepG2 cells. The combined treatment with PD and CQ or BAF may be a promising regimen for hepatocellular carcinoma treatment.


Assuntos
Autofagia/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Saponinas/farmacologia , Triterpenos/farmacologia , Carcinoma Hepatocelular/metabolismo , Linhagem Celular Tumoral , Cloroquina/farmacologia , Humanos , Neoplasias Hepáticas/metabolismo , Macrolídeos/farmacologia
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