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The Nash equilibrium plays a crucial role in game theory. Most of results are based on classical resources. Our goal in this paper is to explore multipartite zero-sum game with quantum settings. We find that in two different settings there is no strategy for a tripartite classical game being fair. Interestingly, this is resolved by providing dynamic zero-sum quantum games using single quantum state. Moreover, the gains of some players may be changed dynamically in terms of the committed state. Both quantum games are robust against the preparation noise and measurement errors.
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Production of protein containing lengthy stretches of polyglutamine encoded by multiple repeats of the trinucleotide CAG is a hallmark of Huntington's disease (HD) and of a variety of other inherited degenerative neurological and neuromuscular disorders. Earlier work has shown that interference with production of the transcription elongation protein SUPT4H results in decreased cellular capacity to transcribe mutant huntingtin gene (Htt) alleles containing long CAG expansions, but has little effect on expression of genes containing short CAG stretches. zQ175 and R6/2 are genetically engineered mouse strains whose genomes contain human HTT alleles that include greatly expanded CAG repeats and which are used as animal models for HD. Here we show that reduction of SUPT4H expression in brains of zQ175 mice by intracerebroventricular bolus injection of antisense 2'-O-methoxyethyl oligonucleotides (ASOs) directed against Supt4h, or in R6/2 mice by deletion of one copy of the Supt4h gene, results in a decrease in mRNA and protein encoded specifically by mutant Htt alleles. We further show that reduction of SUPT4H in mouse brains is associated with decreased HTT protein aggregation, and in R6/2 mice, also with prolonged lifespan and delay of the motor impairment that normally develops in these animals. Our findings support the view that targeting of SUPT4H function may be useful as a therapeutic countermeasure against HD.
Assuntos
Proteínas de Ligação a DNA/genética , Doença de Huntington/genética , Proteínas do Tecido Nervoso/genética , Proteínas Nucleares/genética , Expansão das Repetições de Trinucleotídeos/genética , Alelos , Animais , Comportamento Animal , Encéfalo/metabolismo , Encéfalo/patologia , Proteínas de Ligação a DNA/biossíntese , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Proteína Huntingtina , Doença de Huntington/patologia , Camundongos , Mutação , Proteínas do Tecido Nervoso/biossíntese , Neurônios/metabolismo , Neurônios/patologia , Proteínas Nucleares/biossíntese , Agregação Patológica de Proteínas/genética , RNA Mensageiro/genéticaRESUMO
MAIN CONCLUSION: The Ycf46 mutant of Synechocystis showed growth inhibition under low dissolved CO 2 conditions, suggesting a role for the Ycf46 protein in the process of photosynthetic CO 2 uptake and utilization. Hypothetical chloroplast open reading frame Ycf46 proteins are highly conserved in all cyanobacterial lineages and most algal chloroplast genomes, but their exact function is still unknown. In the cyanobacterium Synechocystis sp. PCC 6803, the Ycf46 encoding gene slr0374 is part of an operon (with slr0373 and slr0376) and responds to many environmental stresses. Transcript levels of the slr0373, slr0374 and slr0376 genes were increased under a low concentration of dissolved inorganic carbon (Ci). Compared with the wild type, the mutant lacking slr0374 showed growth arrest under Ci-deficient conditions but not under iron-deficient or low-light conditions. In addition, the mutant grew more slowly than the wild type under pH 6.0 conditions in which CO2 was the dominant Ci source, indicating the mutant cells had weak CO2 uptake and/or utilization ability. Supplying a high concentration of CO2 (5 %, v/v) to the mutant restored its phenotype to the wild type level. The photosynthetic activity of the mutant was inhibited to a lesser extent by a carbonic anhydrase inhibitor than that of the wild type, which specifically blocked CO2 uptake. Inactivation of slr0374 decreased expression of the ecaB gene and reduced carbonic anhydrase activity. A subcellular localization assay indicated that the Ycf46 protein was soluble. By co-immunoprecipitation assay using Slr0374 as a bait-protein, potential interacting proteins in the size range of 30 kDa were identified. These results suggest that the Ycf46 protein plays a role in the regulation of photosynthesis in cyanobacteria, especially in CO2 uptake and utilization.
Assuntos
Proteínas de Bactérias/metabolismo , Dióxido de Carbono/metabolismo , Óperon , Synechocystis/metabolismo , Proteínas de Bactérias/genética , Carbono/metabolismo , Regulação Bacteriana da Expressão Gênica , Concentração de Íons de Hidrogênio , Imunoprecipitação , Mutação , Fotossíntese/genética , Fotossíntese/fisiologia , Ligação Proteica , Synechocystis/genéticaRESUMO
Cyanobacteria are important players in the global carbon cycle, accounting for approximately 25% of global CO2 fixation. Their CO2-concentrating mechanisms (CCMs) are thought to play a key role in cyanobacterial calcification, but the mechanisms are not completely understood. In Synechocystis sp. strain PCC 6803, a single Ca(2+)/H(+) exchanger (Slr1336) controls the Ca(2+)/H(+) exchange reaction. We knocked out the exchanger and investigated the effects on cyanobacterial calcification and CCMs. Inactivation of slr1336 significantly increased the calcification rate and decreased the zeta potential, indicating a relatively stronger Ca(2+)-binding ability. Some genes encoding CCM-related components showed increased expression levels, including the cmpA gene, which encodes the Ca(2+)-dependent HCO3(-) transporter BCT1. The transcript level of cmpA in the mutant was 30 times that in wild type. A Western blot analysis further confirmed that protein levels of CmpA were higher in the mutant than the wild type. Measurements of inorganic carbon fluxes and O2 evolution proved that both the net HCO3(-) uptake rate and the BCT1 transporter supported photosynthetic rate in the slr1336 mutant were significantly higher than in the wild type. This would cause the mutant cells to liberate more OH(-) ions out of the cell and stimulate CaCO3 precipitation in the microenvironment. We conclude that the mutation of the Ca(2+)/H(+) exchanger in Synechocystis promoted the cyanobacterial calcification process by upregulating CCMs, especially the BCT1 HCO3(-) transporter. These results shed new light on the mechanism by which CCM-facilitated photosynthesis promotes cyanobacterial calcification.
Assuntos
Antiporters/metabolismo , Calcificação Fisiológica/fisiologia , Ciclo do Carbono/fisiologia , Dióxido de Carbono/metabolismo , Proteínas de Transporte de Cátions/metabolismo , Synechocystis/metabolismo , Antiporters/genética , Western Blotting , Carbono/metabolismo , Proteínas de Transporte de Cátions/genética , Ensaio de Desvio de Mobilidade Eletroforética , Mutação/genética , Oxigênio/metabolismo , Fotossíntese/fisiologia , Plasmídeos/genética , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Heat shock protein 90ß (Hsp90ß, encoded by Hsp90ab1 gene) is the most abundant proteins in the cells and contributes to variety of biological processes including metabolism, cell growth and neural functions. However, genetic evidences showing Hsp90ß in vivo functions using tissue specific knockout mice are still lacking. Here, we showed that Hsp90ß exerted paralogue-specific role in osteoclastogenesis. Using myeloid-specific Hsp90ab1 knockout mice, we provided the first genetic evidence showing the in vivo function of Hsp90ß. Hsp90ß binds to Ikkß and reduces its ubiquitylation and proteasomal degradation, thus leading to activated NF-κB signaling. Meanwhile, Hsp90ß increases cholesterol biosynthesis by activating Srebp2. Both pathways promote osteoclastogenic genes expression. Genetic deletion of Hsp90ab1 in osteoclast or pharmacological inhibition of Hsp90ß alleviates bone loss in ovariectomy-induced mice. Therefore, Hsp90ß is a promising druggable target for the treatment of osteoporosis.
Assuntos
NF-kappa B , Osteogênese , Animais , Feminino , Camundongos , Colesterol/metabolismo , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Osteoclastos/metabolismo , Osteogênese/genética , Ligante RANK/metabolismo , Transdução de SinaisRESUMO
SCAP (SREBF chaperone) regulates SREBFs (sterol regulatory element binding transcription factors) processing and stability, and, thus, becomes an emerging drug target to treat dyslipidemia and fatty liver disease. However, the current known SCAP inhibitors, such as oxysterols, induce endoplasmic reticulum (ER) stress and NR1H3/LXRα (nuclear receptor subfamily 1 group H member 3)-SREBF1/SREBP-1 c-mediated hepatic steatosis, which severely limited the clinical application of this inhibitor. In this study, we identified a small molecule, lycorine, which binds to SCAP, which suppressed the SREBF pathway without inducing ER stress or activating NR1H3. Mechanistically, lycorine promotes SCAP lysosomal degradation in a macroautophagy/autophagy-independent pathway, a mechanism completely distinct from current SCAP inhibitors. Furthermore, we determined that SQSTM1 captured SCAP after its exit from the ER. The interaction of SCAP and SQSTM1 requires the WD40 domain of SCAP and the TB domain of SQSTM1. Interestingly, lycorine triggers the lysosome translocation of SCAP independent of autophagy. We termed this novel protein degradation pathway as the SQSTM1-mediated autophagy-independent lysosomal degradation (SMAILD) pathway. In vivo, lycorine ameliorates high-fat diet-induced hyperlipidemia, hepatic steatosis, and insulin resistance in mice. Our study demonstrated that the inhibition of SCAP through the SMAILD pathway could be employed as a useful therapeutic strategy for treating metabolic diseases.Abbreviation: 25-OHD: 25-hydroxyvitamin D; 3-MA: 3-methyladenine; ABCG5: ATP binding cassette subfamily G member 5; ABCG8: ATP binding cassette subfamily G member 8; ACACA: acetyl-CoA carboxylase alpha; AEBSF: 4-(2-aminoethyl) benzenesulfonyl fluoride hydrochloride; AHI: anhydroicaritin; AKT/protein kinase B: AKT serine/threonine kinase; APOE: apolipoprotein E; ATF6: activating transcription factor 6; ATG: autophagy-related; BAT: brown adipose tissue; CD274/PD-L1: CD274 molecule; CETSA: cellular thermal shift assay; CMA: chaperone-mediated autophagy; COPII: cytoplasmic coat protein complex-II; CQ: chloroquine; DDIT3/CHOP: DNA damage inducible transcript 3; DNL: de novo lipogenesis; EE: energy expenditure; EGFR: epithelial growth factor receptor; eMI: endosomal microautophagy; ERN1/IRE1α: endoplasmic reticulum to nucleus signaling 1; FADS2: fatty acid desaturase 2; FASN: fatty acid synthase; GOT1/AST: glutamic-oxaloacetic transaminase 1; GPT/ALT: glutamic-pyruvate transaminase; HMGCR: 3-hydroxy-3-methylglutaryl-CoA reductase; HMGCS1: 3-hydroxy-3-methylglutaryl-CoA synthase 1; HSP90B1/GRP94: heat shock protein 90 beta family member 1; HSPA5/GRP78: heat hock protein family A (Hsp70) member 5; HSPA8/HSC70: heat shock protein family A (Hsp70) member 8; INSIG1: insulin induced gene 1; LAMP2A: lysosomal associated membrane protein 2A; LDLR: low density lipoprotein receptor; LyTACs: lysosome targeting chimeras; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MBTPS1: membrane bound transcription factor peptidase, site 1; MEF: mouse embryonic fibroblast; MST: microscale thermophoresis; MTOR: mechanistic target of rapamycin kinase; MVK: mevalonate kinase; PROTAC: proteolysis targeting chimera; RQ: respiratory quotient; SCAP: SREBF chaperone; SCD1: stearoyl-coenzemy A desaturase 1; SMAILD: sequestosome 1 mediated autophagy-independent lysosomal degradation; SQSTM1: sequestosome 1; SREBF: sterol regulatory element binding transcription factor; TNFRSF10B/DR5: TNF receptor superfamily member 10b; TRAF6: TNF receptor associated factor 6; UPR: unfolded protein response; WAT: white adipose tissue; XBP1: X-box binding protein 1.
Assuntos
Alcaloides de Amaryllidaceae/farmacologia , Dieta Hiperlipídica/efeitos adversos , Hiperlipidemias/metabolismo , Resistência à Insulina , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Lisossomos/metabolismo , Proteínas de Membrana/antagonistas & inibidores , Obesidade/metabolismo , Fenantridinas/farmacologia , Animais , Regulação para Baixo , Células HEK293 , Células Hep G2 , Humanos , Hiperlipidemias/etiologia , Hiperlipidemias/fisiopatologia , Resistência à Insulina/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Lisossomos/fisiologia , Masculino , Proteínas de Membrana/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/etiologia , Obesidade/fisiopatologia , Proteína Sequestossoma-1/metabolismo , Transdução de Sinais/efeitos dos fármacosRESUMO
Osteoporosis develops because of impaired bone formation and/or excessive bone resorption. Several pharmacological treatment of osteoporosis has been developed; however, new treatments are still necessary. Cholesterol and estrogen receptor-related receptor alpha (ERRα) promote osteoclasts formation, survival, and cellular fusion and thus become high risk factors of osteoporosis. In this study, we identified that carnosic acid (CA) suppressed bone loss by dual-targeting of sterol regulatory element-binding protein 2 (SREBP2, a major regulator that regulates cholesterol synthesis) and ERRα. Mechanistically, CA reduced nuclear localization of mature SREBP2 and suppressed de novo biogenesis of cholesterol. CA subsequently decreased the interaction between ERRα and peroxisome proliferator-activated receptor gamma coactivator 1-beta (PGC1ß), resulting in decreased the transcription activity of ERRα and its target genes expression. Meanwhile, CA directly bound to the ligand-binding domain of ERRα and significantly promoted its ubiquitination and proteasomal degradation. Subsequently, STUB1 was identified as the E3 ligase of ERRα. The lysine residues (K51 and K68) are essential for ubiquitination and proteasomal degradation of ERRα by CA. In conclusion, CA dually targets SREBP2 and ERRα, thus inhibits the RANKL-induced osteoclast formation and improves OVX-induced bone loss. CA may serve as a lead compound for pharmacological control of osteoporosis.
Assuntos
Abietanos/farmacologia , Reabsorção Óssea/prevenção & controle , Osteoclastos/metabolismo , Osteogênese , Ovariectomia , Ligante RANK/farmacologia , Receptores de Estrogênio/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo , Animais , Reabsorção Óssea/diagnóstico por imagem , Reabsorção Óssea/etiologia , Reabsorção Óssea/patologia , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Colesterol/metabolismo , Feminino , Humanos , Luciferases/metabolismo , Lisina/metabolismo , Camundongos Endogâmicos C57BL , Proteínas Nucleares/metabolismo , Osteoclastos/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Osteoporose/sangue , Osteoporose/diagnóstico por imagem , Osteoporose/etiologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteólise/efeitos dos fármacos , Fosfatase Ácida Resistente a Tartarato/metabolismo , Fatores de Transcrição/metabolismo , Ubiquitina-Proteína Ligases , Ubiquitinação/efeitos dos fármacos , Receptor ERRalfa Relacionado ao EstrogênioRESUMO
Defect-free graphene is impermeable to gases and liquids but highly permeable to thermal protons. Atomic-scale defects such as vacancies, grain boundaries, and Stone-Wales defects are predicted to enhance graphene's proton permeability and may even allow small ions through, whereas larger species such as gas molecules should remain blocked. These expectations have so far remained untested in experiment. Here, we show that atomically thin carbon films with a high density of atomic-scale defects continue blocking all molecular transport, but their proton permeability becomes â¼1000 times higher than that of defect-free graphene. Lithium ions can also permeate through such disordered graphene. The enhanced proton and ion permeability is attributed to a high density of eight-carbon-atom rings. The latter pose approximately twice lower energy barriers for incoming protons compared to that of the six-atom rings of graphene and a relatively low barrier of â¼0.6 eV for Li ions. Our findings suggest that disordered graphene could be of interest as membranes and protective barriers in various Li-ion and hydrogen technologies.
RESUMO
The title compound, C(20)H(14)N(4)O(2), crystallizes in the ortho-rhom-bic system with a crystallographic twofold axis through the N-N bond. The mol-ecule is non-planar and the dihedral angle between two amide groups is 74.9â (2)°. An intra-molecular N-Hâ¯N hydrogen bond is present. In the crystal, the mol-ecules are packed in chains running along the c axis through inter-molecular N-Hâ¯O hydrogen bonds. These chains are further stabilized by inter-molecular C-Hâ¯O hydrogen bonds and C-Hâ¯π inter-actions leading to the formation of a three-dimensional network.
RESUMO
Despite the massive efforts to develop the treatment of pancreatic cancers, no effective application exhibits satisfactory clinical outcome. Macropinocytosis plays a critical role for continuous proliferation of pancreatic ductal adenocarcinoma (PDAC). In this study, we generated a screening method and identified phellodendrine chloride (PC) as a potential macropinocytosis inhibitor. PC significantly inhibited the viability of KRAS mutant pancreatic cancer cells (PANC-1 and MiaPaCa-2) in a dose-dependent manner; however, it did not affect the wild type KRAS pancreatic cancer cells (BxPC-3). Further experiments indicated that PC reduced the growth of PANC-1 cells through inhibition of macropinocytosis and diminishing the intracellular glutamine level. Disruption of glutamine metabolism led to enhance the reactive oxygen species level and induce mitochondrial membrane potential depolarization in PANC-1 cells. PC treatment caused increased Bax and decreased Bcl-2 expression, along with the activation of cleaved caspase-3, 7, 9 and cleaved-PARP, thus induced mitochondrial apoptosis. Moreover, PC inhibited macropinocytosis in vivo and effectively reduced the growth of PANC-1 xenograft tumors. All together, we demonstrated that inhibition of macropinocytosis might be an effective strategy to treat pancreatic cancers. Thus, PC could be a potential compound with improved therapeutic efficacy in patients with pancreatic cancers.
Assuntos
Mutação , Nutrientes/metabolismo , Neoplasias Pancreáticas/patologia , Pinocitose/efeitos dos fármacos , Proteínas Proto-Oncogênicas p21(ras)/genética , Quinolizinas/farmacologia , Animais , Apoptose/efeitos dos fármacos , Caspases/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Glutamina/metabolismo , Humanos , Espaço Intracelular/efeitos dos fármacos , Espaço Intracelular/metabolismo , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/patologia , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Human neuroglobin (Ngb) forms an intramolecular disulfide bond between Cys46 and Cys55, with a third Cys120 near the protein surface, which is a promising protein model for heme protein design. In order to protect the free Cys120 and to enhance the protein stability, we herein developed a strategy by designing an additional disulfide bond between Cys120 and Cys15 via A15C mutation. The design was supported by molecular modeling, and the formation of Cys15-Cys120 disulfide bond was confirmed experimentally by ESI-MS analysis. Molecular modeling, UV-Vis and CD spectroscopy showed that the additional disulfide bond caused minimal structural alterations of Ngb. Meanwhile, the disulfide bond of Cys15-Cys120 was found to enhance both Gdn·HCl-induced unfolding stability (increased by â¼0.64 M) and pH-induced unfolding stability (decreased by â¼0.69 pH unit), as compared to those of WT Ngb with a single native disulfide bond of Cys46-Cys55. Moreover, the half denaturation temperature (T m) of A15C Ngb was determined to be higher than 100 °C. In addition, the disulfide bond of Cys15-Cys120 has slight effects on protein function, such as an increase in the rate of O2 release by â¼1.4-fold. This study not only suggests a crucial role of the artificial disulfide in protein stabilization, but also lays the groundwork for further investigation of the structure and function of Ngb, as well as for the design of other functional heme proteins, based on the scaffold of A15C Ngb with an enhanced stability.
RESUMO
Rationale: Heat shock protein 9 (HSP90) are a family of the most highly expressed cellular proteins and attractive drug targets against cancer, neurodegeneration diseases, etc. HSP90 proteins have also been suggested to be linked to lipid metabolism. However, the specific function of HSP90 paralogs, as well as the underlying molecular cascades remains largely unknown. This study aims to unravel the paralog-specific role of HSP90 in lipid metabolism and try to discover paralog-specific HSP90 inhibitors. Methods: In non-alcohol fatty liver disease (NAFLD) patients, as well as in diet induced obese (DIO) mice, expression of HSP90 paralogs were analyzed by immunohistochemistry and western blot. In hepatocytes and in DIO mice, HSP90 proteins were knockdown by siRNAs/shRNAs, metabolic parameters, as well as downstream signaling were then investigated. By virtue screening, corylin was found to bind specifically to HSP90ß. Using photo-affinity labeling and mass spectrum, corylin binding proteins were identified. After oral administration of corylin, its lipid lowering effects in different metabolic disease mice models were evaluated. Results: We showed that hepatic HSP90ß, rather than HSP90α, was overexpressed in NAFLD patients and obese mice. Hepatic HSP90ß was also clinical relevant to serum lipid level. Depletion of HSP90ß promoted mature sterol regulatory element-binding proteins (mSREBPs) degradation through Akt-GSK3ß-FBW7 pathway, thereby dramatically decreased the content of neutral lipids and cholesterol. We discovered an HSP90ß-selective inhibitor (corylin) that only bound to its middle domain. We found that corylin treatment partially suppressed Akt activity only at Thr308 site and specifically promoted mSREBPs ubiquitination and proteasomal degradation. Corylin treatment significantly reduced lipid content in both liver cell lines and human primary hepatocytes. In animal studies, we showed that corylin ameliorated obesity-induced fatty liver disease, type 2 diabetes and atherosclerosis. Principle conclusions: HSP90ß plays a parolog-specific role in regulating lipid homeostasis. Compound that selectively inhibits HSP90ß could be useful in the clinic for the treatment for metabolic diseases.
Assuntos
Proteínas de Choque Térmico HSP90/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteínas de Ligação a Elemento Regulador de Esterol/metabolismo , Ubiquitina/metabolismo , Animais , Linhagem Celular Tumoral , Flavonoides/metabolismo , Células HEK293 , Humanos , Metabolismo dos Lipídeos/fisiologia , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica/metabolismo , Obesidade/metabolismo , Ligação ProteicaRESUMO
DL-mandelic acid (MA) has been intercalated into Zn-Al layered double hydroxide (LDH) by an anion-exchange reaction. After intercalation of MA anions, the basal spacing of the LDH increased from 0.75 to 1.46â¯nm, suggesting that the MA anions were successfully intercalated into the interlayer galleries of the LDH. The structure and the thermal stability of the samples were characterized by XRD, FT-IR, TG-DTA. Studies of MA release from ZnAl-MA-LDH in hydrochloric solution (pHâ¯=â¯4) imply that ZnAl-MA-LDH is a better controlled release system than pure MA. Meanwhile, the mechanisms of slow release were assessed by using four commonly kinetic models. Finally, the antimicrobial activity of ZnAl-MA-LDH was tested against two kinds of bacteria and a fungus. The study confirms that the mandelic ions intercalated LDHs have the potential application as a slow release preservative in the future.
Assuntos
Alumínio/química , Anti-Infecciosos/farmacologia , Hidróxidos/química , Substâncias Intercalantes/química , Ácidos Mandélicos/química , Zinco/química , Análise Diferencial Térmica , Liberação Controlada de Fármacos , Cinética , Testes de Sensibilidade Microbiana , Temperatura , Termogravimetria , Difração de Raios XRESUMO
The structure and function of heme proteins are regulated by diverse post-translational modifications including heme-protein cross-links, with the underlying mechanisms not well understood. In this study, we introduced a Cys (K42C) close to the heme 4-vinyl group in sperm whale myoglobin (Mb) and solved its X-ray crystal structure. Interestingly, we found that K42C Mb can partially form a Cys-heme cross-link (termed K42C Mb-X) under dithiothreitol-induced reductive conditions in presence of O2, as suggested by guanidine hydrochloride-induced unfolding and heme extraction studies. Mass spectrometry (MS) studies, together with trypsin digestion studies, further indicated that a thioether bond is formed between Cys42 and the heme 4-vinyl group with an additional mass of 16â¯Da, likely due to hydroxylation of the αcarbon. We then proposed a plausible mechanism for the formation of the novel Cys-heme cross-link based on MS, kinetic UV-vis and electron paramagnetic resonance (EPR) studies. Moreover, the Cys-heme cross-link was shown to fine-tune the protein reactivity toward activation of H2O2. This study provides valuable insights into the post-translational modification of heme proteins, and also suggests that the Cys-heme cross-link can be induced to form in vitro, making it useful for design of new heme proteins with a non-dissociable heme and improved functions.
Assuntos
Mioglobina/química , Oxigênio/química , Animais , Cristalografia por Raios X , Espectroscopia de Ressonância de Spin Eletrônica , Heme , Espectrometria de Massas , Oxirredução , CachaloteRESUMO
The effectiveness of rapid rail transit system is analyzed using tools of complex network for the first time. We evaluated the effectiveness of the system in Beijing quantitatively from different perspectives, including descriptive statistics analysis, bridging property, centrality property, ability of connecting different part of the system and ability of disease spreading. The results showed that the public transport of Beijing does benefit from the rapid rail transit lines, and the benefit of different regions from RRTS is gradually decreased from the north to the south. The paper concluded with some policy suggestions regarding how to promote the system. This study offered significant insight that can help understand the public transportation better. The methodology can be easily applied to analyze other urban public systems, such as electricity grid, water system, to develop more livable cities.
Assuntos
Meios de Transporte/métodos , Algoritmos , Pequim , Modelos Teóricos , Meios de Transporte/legislação & jurisprudênciaRESUMO
INTRODUCTION: Massive transfusion protocol (MTP) is increasingly used in civilian trauma cases to achieve better haemostatic resuscitation in patients requiring massive blood transfusions (MTs), with improved survival outcomes. However, in non-trauma patients, evidence for MTP is lacking. This study aims to assess the outcomes of a newly established MTP in a civilian setting, for both trauma and non-trauma patients, in an acute surgical care unit. METHODS: A retrospective cohort analysis was performed on 46 patients for whom MTP was activated in Changi General Hospital, Singapore. The patients were categorised into trauma and non-trauma groups. Assessment of Blood Consumption (ABC) score was used to identify MTP trauma patients and analyse over-activation rates. RESULTS: Only 39.1% of all cases with MTP activation eventually received MTs; 39.8% of the MTs were for non-trauma patients. Mean fresh frozen plasma to packed red blood cells (pRBC) ratio achieved with MTP was 0.741, while mean platelet to pRBC ratio was 0.213. The 24-hour mortality rate for all patients who received an MT upon MTP activation was 33.3% (trauma vs. non-trauma group: 45.5% vs. 14.3%). The ABC scoring system used for trauma patients had a sensitivity and specificity of 81.8% and 41.2%, respectively. CONCLUSION: MTP may be used for both trauma and non-trauma patients in acute care surgery. Scoring systems to predict the need for an MT, improved compliance to predefined transfusion ratios and regular reviews of the MTP are necessary to optimise MTPs and to improve the outcomes of patients receiving MTs.
Assuntos
Transfusão de Sangue/métodos , Medicina de Emergência/métodos , Plasma , Ressuscitação/métodos , Ferimentos e Lesões/terapia , Adulto , Idoso , Medicina de Emergência/tendências , Feminino , Serviços de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde , Estudos Retrospectivos , Índice de Gravidade de Doença , Singapura , Resultado do TratamentoRESUMO
The EGFR and B-Raf(V600E) dual inhibition is a promising strategy in treatment of colorectal cancer patients with B-Raf(V600E) mutation. Previously, compound 3 was designed and synthesized as a novel B-Raf(V600E) and EGFR dual inhibitor with highly potency in both kinase and cell based assay. Herein, a sensitive and rapid HPLC-MS/MS quantitative method was developed and validated for the further pharmacokinetic evaluation of compound 3 in rats.
Assuntos
Receptores ErbB/antagonistas & inibidores , Inibidores de Proteínas Quinases/sangue , Inibidores de Proteínas Quinases/farmacocinética , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Espectrometria de Massas em Tandem/métodos , Animais , Cromatografia Líquida de Alta Pressão/métodos , Receptores ErbB/metabolismo , Feminino , Masculino , Proteínas Proto-Oncogênicas B-raf/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
Artocarpin, a natural prenylated flavonoid, has been shown to have various biological properties. However, its effects on human cutaneous squamous cell carcinoma (SCC) have not been previously investigated. We set out to determine whether artocarpin has cytotoxic effects on SCC cells and whether its pharmacological activity is dependent on protein-nutrient concentration. Our results showed that treatment of HSC-1 cells (a human cutaneous SCC cell line) with artocarpin decreased cell viability and induced cell apoptosis by increasing caspase 3/7 activity. These effects were more pronounced at low fetal bovine serum (FBS) concentrations. Artocarpin induced an increase in the level of phospho-p38 and a decrease in the levels of phospho-ERK, phospho-JNK, phospho-Akt, phospho-mTOR, and phospho-S6K. High FBS concentrations in the culture media inhibited and delayed the uptake of artocarpin from the extracellular compartment (culture media) into the intracellular compartment, as determined by high performance liquid chromatography (HPLC) analysis. In conclusion, artocarpin induces apoptosis in HSC-1 cells through modulation of MAPK and Akt/mTOR pathways. Binding of artocarpin to proteins in the FBS may inhibit cellular uptake and reduce the cytotoxic activity of artocarpin on HSC-1 cells. Therefore, artocarpin may have potential use in the future as a form of treatment for cutaneous SCC.