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BACKGROUND: The mRNA-1345 vaccine demonstrated efficacy against RSV disease with acceptable safety in adults ≥60 years in the ConquerRSV trial. Here, humoral immunogenicity results from the trial are presented. METHODS: This phase 2/3 trial randomly assigned adults (≥60 years) to mRNA-1345 50-µg encoding prefusion F (preF) glycoprotein (n = 17,793) vaccine or placebo (n = 17,748). RSV-A and RSV-B neutralizing antibody (nAb) and preF binding antibody (bAb) levels at baseline and day 29 post-vaccination were assessed in a per-protocol immunogenicity subset ([PPIS]; mRNA-1345, n = 1515; placebo, n = 333). RESULTS: Day 29 nAb geometric mean titers (GMTs) increased 8.4-fold against RSV-A and 5.1-fold against RSV-B from baseline. Seroresponses (4-fold rise from baseline) in the mRNA-1345 groups were 74.2% and 56.5% for RSV-A and RSV-B, respectively. Baseline GMTs were lower among participants who met the seroresponse criteria than those who did not. mRNA-1345 induced preF bAbs at day 29, with a pattern similar to nAbs. Day 29 antibody responses across demographic and risk subgroups were generally consistent with the overall PPIS. CONCLUSION: mRNA-1345 enhanced RSV-A and RSV-B nAbs and preF bAbs in adults (≥60 years) across various subgroups, including those at risk for severe disease, consistent with its demonstrated efficacy in the prevention of RSV disease.
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OBJECTIVES: Human metapneumovirus (hMPV) and parainfluenza virus type 3 (PIV3) are common respiratory illnesses in children. The safety and immunogenicity of an investigational mRNA-based vaccine, mRNA-1653, encoding membrane-anchored fusion proteins of hMPV and PIV3, was evaluated in hMPV/PIV3-seropositive children. METHODS: In this phase 1b randomized, observer-blind, placebo-controlled, dose-ranging study, hMPV/PIV3-seropositive children were enrolled sequentially into 2 dose levels of mRNA-1653 administered 2 months apart; children aged 12 to 36 months were randomized (1:1) to receive 10-µg of mRNA-1653 or placebo and children aged 12 to 59 months were randomized (3:1) to receive 30-µg of mRNA-1653 or placebo. RESULTS: Overall, 27 participants aged 18 to 55 months were randomized; 15 participants received 10-µg of mRNA-1653 (n = 8) or placebo (n = 7), whereas 12 participants received 30-µg of mRNA-1653 (n = 9) or placebo (n = 3). mRNA-1653 was well-tolerated at both dose levels. The only reported solicited local adverse reaction was tenderness at injection site; solicited systemic adverse reactions included grade 1 or 2 chills, irritability, loss of appetite, and sleepiness. A single 10-µg or 30-µg mRNA-1653 injection increased hMPV and PIV3 neutralizing antibody titers (geometric mean fold-rise ratio over baseline: hMPV-A = 2.9-6.1; hMPV-B = 6.2-13.2; PIV3 = 2.8-3.0) and preF and postF binding antibody concentrations (geometric mean fold-rise ratio: hMPV preF = 5.3-6.1; postF = 4.6-6.5 and PIV3 preF = 13.9-14.2; postF = 11.0-12.1); a second injection did not further increase antibody levels in these seropositive children. Binding antibody responses were generally preF biased. CONCLUSIONS: mRNA-1653 was well-tolerated and boosted hMPV and PIV3 antibody levels in seropositive children aged 12 to 59 months, supporting the continued development of mRNA-1653 or its components for the prevention of hMPV and PIV3.
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Vírus da Parainfluenza 3 Humana , Humanos , Feminino , Masculino , Pré-Escolar , Lactente , Vírus da Parainfluenza 3 Humana/imunologia , Vírus da Parainfluenza 3 Humana/genética , Metapneumovirus/imunologia , Metapneumovirus/genética , Método Simples-Cego , Infecções por Paramyxoviridae/prevenção & controle , Infecções por Paramyxoviridae/imunologia , Anticorpos Antivirais/sangue , Vacinas contra Parainfluenza/imunologia , Vacinas contra Parainfluenza/administração & dosagem , Vacinas contra Parainfluenza/genética , Imunogenicidade da Vacina , RNA MensageiroRESUMO
BACKGROUND: An mRNA-based RSV vaccine, mRNA-1345, is under clinical investigation to address RSV disease burden in older adults. METHODS: This phase 1, randomized, observer-blind, placebo-controlled, dose-ranging study evaluated safety, reactogenicity, and immunogenicity of mRNA-1345 in adults 65-79 years (NCT04528719). Participants were randomized to receive 1-dose of mRNA-1345 (12.5, 25, 50, 100, or 200-µg) or placebo and matched mRNA-1345 booster or placebo at 12-months. RESULTS: Overall, 298 participants received the first injection; 247 received the 12-month booster injection. mRNA-1345 was generally well-tolerated after both injections, with the most frequently reported solicited adverse reactions being injection-site pain, fatigue, headache, arthralgia, and myalgia. Reactogenicity was higher after the booster injection than the first injection but similar severity, time-to-onset, and duration. A single mRNA-1345 injection boosted RSV-A and RSV-B neutralizing antibody titers (nAb) and prefusion-F-binding antibody (preF-bAb) concentrations at 1-month (geometric mean-fold rises: RSV-A, 10.2-16.5; RSV-B, 5.3-12.5; preF-bAb, 7.2-12.1). RSV antibody levels remained above baseline through 12-months, indicating immune persistence. A 12-month booster injection also increased RSV-A and RSV-B nAb titers and preF-bAb concentrations; titers post-booster injection were numerically lower compared to titers after the first-dose, with overlapping 95% CIs. CONCLUSIONS: mRNA-1345 was well-tolerated and immunogenic following a single injection and a 12-month booster. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04528719.
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BACKGROUND: Respiratory syncytial virus (RSV) presents a global health concern. A lipid nanoparticle-encapsulated mRNA-based RSV vaccine (mRNA-1345) encoding the membrane-anchored RSV prefusion stabilised F glycoprotein (preF) is under clinical investigation. METHODS: This phase 1, randomized, observer-blind, placebo-controlled dose escalation study assessed safety and immunogenicity of mRNA-1345 in healthy adults aged 18-49 years (NCT04528719). Participants were randomized to receive one dose of mRNA-1345 (50, 100, or 200â µg) or placebo, or 3 doses of mRNA-1345 (100â µg) or placebo 56 days apart. RESULTS: mRNA-1345 was well-tolerated at all dose levels. The most common solicited adverse reactions were pain, headache, fatigue, myalgia, or chills, which were all generally mild to moderate. A single injection of mRNA-1345 boosted RSV neutralizing antibody titers (geometric mean fold rise [GMFR]: RSV-A, 20.0 to 23.5; RSV-B, 11.7 to 16.0) and RSV preF binding antibody concentrations (GMFR: 16.1 to 21.8) at 1 month post injection, with no apparent dose response. Antibody levels remained above baseline through 6 months. Sequential doses of 100â µg were well tolerated but did not further boost antibody levels. CONCLUSIONS: A single mRNA-1345 injection demonstrated an acceptable safety profile in younger adults and induced a durable neutralizing antibody response, supporting its continued development.
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BACKGROUND: Respiratory syncytial virus (RSV) can cause substantial morbidity and mortality among older adults. An mRNA-based RSV vaccine, mRNA-1345, encoding the stabilized RSV prefusion F glycoprotein, is under clinical investigation. METHODS: In this ongoing, randomized, double-blind, placebo-controlled, phase 2-3 trial, we randomly assigned, in a 1:1 ratio, adults 60 years of age or older to receive one dose of mRNA-1345 (50 µg) or placebo. The two primary efficacy end points were the prevention of RSV-associated lower respiratory tract disease with at least two signs or symptoms and with at least three signs or symptoms. A key secondary efficacy end point was the prevention of RSV-associated acute respiratory disease. Safety was also assessed. RESULTS: Overall, 35,541 participants were assigned to receive the mRNA-1345 vaccine (17,793 participants) or placebo (17,748). The median follow-up was 112 days (range, 1 to 379). The primary analyses were conducted when at least 50% of the anticipated cases of RSV-associated lower respiratory tract disease had occurred. Vaccine efficacy was 83.7% (95.88% confidence interval [CI], 66.0 to 92.2) against RSV-associated lower respiratory tract disease with at least two signs or symptoms and 82.4% (96.36% CI, 34.8 to 95.3) against the disease with at least three signs or symptoms. Vaccine efficacy was 68.4% (95% CI, 50.9 to 79.7) against RSV-associated acute respiratory disease. Protection was observed against both RSV subtypes (A and B) and was generally consistent across subgroups defined according to age and coexisting conditions. Participants in the mRNA-1345 group had a higher incidence than those in the placebo group of solicited local adverse reactions (58.7% vs. 16.2%) and of systemic adverse reactions (47.7% vs. 32.9%); most reactions were mild to moderate in severity and were transient. Serious adverse events occurred in 2.8% of the participants in each trial group. CONCLUSIONS: A single dose of the mRNA-1345 vaccine resulted in no evident safety concerns and led to a lower incidence of RSV-associated lower respiratory tract disease and of RSV-associated acute respiratory disease than placebo among adults 60 years of age or older. (Funded by Moderna; ConquerRSV ClinicalTrials.gov number, NCT05127434.).
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Infecções por Vírus Respiratório Sincicial , Vacinas contra Vírus Sincicial Respiratório , Vírus Sincicial Respiratório Humano , Vacinas de mRNA , Idoso , Humanos , Anticorpos Antivirais , Método Duplo-Cego , Infecções por Vírus Respiratório Sincicial/epidemiologia , Infecções por Vírus Respiratório Sincicial/prevenção & controle , Vírus Sincicial Respiratório Humano/genética , Doenças Respiratórias/diagnóstico , Doenças Respiratórias/epidemiologia , Doenças Respiratórias/prevenção & controle , Resultado do Tratamento , Vacinas de mRNA/efeitos adversos , Vacinas de mRNA/uso terapêutico , Vacinas contra Vírus Sincicial Respiratório/efeitos adversos , Vacinas contra Vírus Sincicial Respiratório/uso terapêutico , Pessoa de Meia-IdadeRESUMO
The Health and environmental hazards of benzene and nitrobenzene (NB) derivatives have remained a topic of interest of researchers. In silico methods for prediction of toxicity of chemicals have proved their worth in accurate forecast of environmental as well as health toxicity and are strongly recommended by regulatory authorities. Two quantitative structure-toxicity relationship (QSTR) models explaining Scenedesmus obliquus toxicity trends among 39 benzene derivatives and Tetrahymena pyriformis toxicity of 103 NB and 392 benzene derivatives are developed using semiempirical quantum chemical parameters. The best constructed QSTR models have good fitting ability (R2 = 0.8053, 0.7591, and 0.8283) and robustness (Q2LOO = 0.7507, 0.7227, and 0.8194; Q2LMO = 0.7338, 0.7153, and 0.8172). The external predictivity of all the models are quite good (R2EXT = 0.8256, 0.9349, and 0.8698). Electronegativity, Cosmo volume, total energy, and molecular weight are responsible for the increase and decrease of toxicity of benzene derivatives against S. obliquus while electronegativity, electrophilicity index, the heat of formation, total energy, hydrophobicity, and cosmo volume are responsible for modulation of toxicity of NB and benzene derivatives toward T. pyriformis. These models fulfill the requirements of all the five OECD principles.
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Derivados de Benzeno , Tetrahymena pyriformis , Derivados de Benzeno/química , Derivados de Benzeno/toxicidade , Relação Quantitativa Estrutura-Atividade , NitrobenzenosRESUMO
Sesamol (SES) possesses remarkable chemotherapeutic activity, owing to its anti-inflammatory and antioxidant potential. However, the activity of SES is mainly hampered by its poor physicochemical properties and stability issues. Hence, to improve the efficacy of this natural anti-inflammatory and cytotoxic agent, it was loaded into ß-cyclodextrin nanosponges (NS) prepared using different molar ratios of polymer and crosslinker (diphenyl carbonate). The particle size of SES-laden NS (SES-NS) was shown to be in the nano range (200 to 500 nm), with a low polydispersity index, an adequate charge (-17 to -26 mV), and a high payload. Field emission scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy were used to characterize the bioactive-loaded selected batch (SES-NS6). This batch of nanoformulations showed improved solubilization efficacy (701.88 µg/mL) in comparison to bare SES (244.36 µg/mL), polymer (ß-CD) (261.43 µg/mL), and other fabricated batches. The drug release data displayed the controlled release behavior of SES from NS. The findings of the egg albumin denaturation assay revealed the enhanced anti-inflammatory potential of SES-NS as compared to bare SES. Further, the cytotoxicity assay showed that SES-NS was more effective against B16F12 melanoma cell lines than the bioactive alone. The findings of this assay demonstrated a reduction in the IC50 values of SES-NS (67.38 µg/mL) in comparison to SES (106 µg/mL). The present investigation demonstrated the in vitro controlled release pattern and the enhanced anti-inflammatory and cytotoxic activity of SES-NS, suggesting its potential as a promising drug delivery carrier for topical delivery.
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Monoamine oxidase enzyme is necessary for the management of brain functions. It oxidatively metabolizes monoamines and produces ammonia, aldehyde and hydrogen peroxide as by-products. Excessive production of by-products of monoamine metabolism generates free radicals which cause cellular apoptosis and several neurodegenerative disorders for example Alzheimer's disease, Parkinson's disease, depression and autism. The inhibition of MAOs is an attractive target for the treatment of neurological disorders. Clinically approved MAO inhibitors for example selegiline, rasagiline, clorgyline, pargyline etc. are irreversible in nature and cause some adverse effects while recently studied reversible MAO inhibitors are devoid of harmful effects of old monoamine oxidase inhibitors. In this review article we have listed various synthesized molecules containing different moieties like coumarin, chalcone, thiazole, thiourea, caffeine, pyrazole, chromone etc. along with their activity, mode of action, structure activity relationship and molecular docking studies.
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Chalconas , Inibidores da Monoaminoxidase , Aldeídos , Amônia , Cafeína , Cromonas , Clorgilina , Cumarínicos , Peróxido de Hidrogênio , Simulação de Acoplamento Molecular , Monoaminoxidase/metabolismo , Inibidores da Monoaminoxidase/química , Inibidores da Monoaminoxidase/farmacologia , Pargilina , Pirazóis , Selegilina/farmacologia , Relação Estrutura-Atividade , Tiazóis , TioureiaRESUMO
The present piece of research work is framed for improving the solubility of ketoprofen by forming co-crystal using fumaric acid as a coformer. Co-crystal of ketoprofen and fumaric acid was prepared by simple solvent-assisted grinding method, containing drug and coformer as independent variables and solubility and % drug release were assumed to be dependent variables. Differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, nuclear magnetic resonance and scanning electron microscopy techniques were used to characterize the preparation of optimized batch of co-crystal and further, evaluated for in vitro and in vivo anti-inflammatory and analgesic activities. Based on results of solubility and dissolution rate studies the formulation showed magnified improvement in both the properties on co-crystallization. The values of Gibbs free energy are negative at all levels of carrier demonstrating spontaneity of the drug solubilization process. The IC50 value of optimized batch of co-crystal formulation and the pure drug was observed as 327.33 µg/ml and 556.11 µg/ml, respectively, demonstrating that co-crystal formulation possesses more percentage protection against protein denaturation than the drug ketoprofen. In vivo (anti-inflammatory and analgesic) activities revealed that optimized batch of co-crystal formulation delivered a rapid pharmacological response in Wistar rats and albino mice when compared with standard drug.
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Cetoprofeno , Animais , Varredura Diferencial de Calorimetria , Camundongos , Ratos , Ratos Wistar , Solubilidade , Difração de Raios XRESUMO
Hereditary angioedema (HAE) types I and II are characterized by functional C1 inhibitor (fC1-INH) deficiency which results in bradykinin overproduction. Sensitive, specific and robust methods to quantitate fC1-INH in human samples are required for diagnosing HAE and/or to measure pharmacodynamic activity of C1-INH drugs in clinical studies. To date, three methods have been reported in literature to measure fC1-INH: conventional chromogenic assay measuring residual C1-esterase activity, and immunoassays based on functional binding to either activated complement C1s or Factor XIIa/kallikrein. We used three qualified/validated fit-for purpose methods to quantitate fC1-INH in human plasma and to conduct a parallel comparison for diagnostic purposes and as a read-out for pharmacodynamic activity. Sensitivity and specificity were determined from the Receiver Operator Characteristics (ROC) curve analysis of the three fC1-INH methods through testing of fifty healthy control vs. HAE plasma samples. fC1-INH profile of fifteen HAE subjects, who underwent different treatment regimen in a cross-over Shire C1-INH clinical study, was analyzed in these three methods in parallel. A correlation analysis performed between these methods using data generated from clinical samples showed that profiles obtained from different fC1-INH methods matched for individual HAE subjects. Our findings suggest that functional binding immunoassay methods serve as reliable alternates for conventional chromogenic method to quantitate fC1-INH in human plasma samples with a better dynamic range of detection and ease of use. Of the two immunoassays used in this study, FXIIa-binding method gave better sensitivity, specificity, and correlation to the chromogenic method as a diagnostic method to distinguish HAE samples from healthy controls.
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Angioedemas Hereditários/diagnóstico , Proteína Inibidora do Complemento C1/análise , Imunoensaio/métodos , Compostos Cromogênicos , Estudos Cross-Over , Progressão da Doença , Método Duplo-Cego , Feminino , Humanos , Masculino , Efeito Placebo , Curva ROC , Sensibilidade e EspecificidadeRESUMO
Early in pancreatic development, epithelial cells of pancreatic buds function as primary multipotent progenitor cells (1°MPC) that specify all three pancreatic cell lineages, i.e., endocrine, acinar and duct. Bipotent "Trunk" progenitors derived from 1°MPC are implicated in directly regulating the specification of endocrine progenitors. It is unclear if this specification process is initiated in the 1°MPC where some 1°MPC become competent for later specification of endocrine progenitors. Previously we reported that in Pdx1tTA/+;tetOMafA (bigenic) mice inducing expression of transcription factor MafA in Pdx1-expressing (Pdx1+) cells throughout embryonic development inhibited the proliferation and differentiation of 1°MPC cells, resulting in reduced pancreatic mass and endocrine cells by embryonic day (E) 17.5. Induction of the transgene only until E12.5 in Pdx1+ 1°MPC was sufficient for this inhibition of endocrine cells and pancreatic mass at E17.5. However, by birth (P0), as we now report, such bigenic pups had significantly increased pancreatic and endocrine volumes with endocrine clusters containing all pancreatic endocrine cell types. The increase in endocrine cells resulted from a higher proliferation of tubular epithelial cells expressing the progenitor marker Glut2 in E17.5 bigenic embryos and increased number of Neurog3-expressing cells at E19.5. A BrdU-labeling study demonstrated that inhibiting proliferation of 1°MPC by forced MafA-expression did not lead to retention of those progenitors in E17.5 tubular epithelium. Our data suggest that the forced MafA expression in the 1°MPC inhibits their competency to specify endocrine progenitors only until E17.5, and after that compensatory proliferation of tubular epithelium gives rise to a distinct pool of endocrine progenitors. Thus, these bigenic mice provide a novel way to characterize the competency of 1°MPC for their ability to specify endocrine progenitors, a critical limitation in our understanding of endocrine differentiation.
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Epitélio/fisiologia , Pâncreas/fisiologia , Células-Tronco/fisiologia , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Diferenciação Celular/fisiologia , Linhagem da Célula/fisiologia , Células Endócrinas/metabolismo , Células Endócrinas/fisiologia , Sistema Endócrino/metabolismo , Sistema Endócrino/fisiologia , Células Epiteliais/metabolismo , Células Epiteliais/fisiologia , Epitélio/metabolismo , Feminino , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Transportador de Glucose Tipo 2/metabolismo , Fatores de Transcrição Maf Maior/metabolismo , Camundongos , Camundongos Transgênicos , Proteínas do Tecido Nervoso/metabolismo , Pâncreas/metabolismo , Gravidez , Células-Tronco/metabolismoRESUMO
Over the last decade, our knowledge of ß-cell biology has expanded with the use of new scientific techniques and strategies. Growth factors, hormones and small molecules have been shown to enhance ß-cell proliferation and function. Stem cell technology and research into the developmental biology of the pancreas have yielded new methods for in vivo and in vitro regeneration of ß cells from stem cells and endogenous progenitors as well as transdifferentiation of non-ß cells. Novel pharmacological approaches have been developed to preserve and enhance ß-cell function. Strategies to increase expression of insulin gene transcription factors in dysfunctional and immature ß cells have ameliorated these impairments. Hence, we suggest that strategies to minimize ß-cell loss and to increase their function and regeneration will ultimately lead to therapy for both Type 1 and 2 diabetes.
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Notch signaling inhibits differentiation of endocrine cells in the pancreas and intestine. In a number of cases, the observed inhibition occurred with Notch activation in multipotential cells, prior to the initiation of endocrine differentiation. It has not been established how direct activation of Notch in endocrine precursor cells affects their subsequent cell fate. Using conditional activation of Notch in cells expressing Neurogenin3 or NeuroD1, we examined the effects of Notch in both organs, on cell fate of early endocrine precursors and maturing endocrine-restricted cells, respectively. Notch did not preclude the differentiation of a limited number of endocrine cells in either organ when activated in Ngn3(+) precursor cells. In addition, in the pancreas most Ngn3(+) cells adopted a duct but not acinar cell fate; whereas in intestinal Ngn3(+) cells, Notch favored enterocyte and goblet cell fates, while selecting against endocrine and Paneth cell differentiation. A small fraction of NeuroD1(+) cells in the pancreas retain plasticity to respond to Notch, giving rise to intraislet ductules as well as cells with no detectable pancreatic lineage markers that appear to have limited ultrastructural features of both endocrine and duct cells. These results suggest that Notch directly regulates cell fate decisions in multipotential early endocrine precursor cells. Some maturing endocrine-restricted NeuroD1(+) cells in the pancreas switch to the duct lineage in response to Notch, indicating previously unappreciated plasticity at such a late stage of endocrine differentiation.
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Diferenciação Celular , Células Endócrinas/citologia , Intestinos/citologia , Pâncreas/citologia , Receptores Notch/metabolismo , Transdução de Sinais , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Linhagem da Célula , Células Endócrinas/metabolismo , Mucosa Intestinal/metabolismo , Camundongos , Camundongos Transgênicos , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Pâncreas/metabolismoRESUMO
The human pathogens enteropathogenic Escherichia coli (EPEC) and vaccinia virus trigger actin assembly in host cells by activating the host adaptor Nck and the actin nucleation promoter neural Wiskott-Aldrich syndrome protein (N-WASP). EPEC translocates effector molecules into host cells via type III secretion, and the interaction between the translocated intimin receptor (Tir) and the bacterial membrane protein intimin stimulates Nck and N-WASP recruitment, leading to the formation of actin pedestals beneath adherent bacteria. Vaccinia virus also recruits Nck and N-WASP to generate actin tails that promote cell-to-cell spread of the virus. In addition to Nck and N-WASP, WASP-interacting protein (WIP) localizes to vaccinia virus tails, and inhibition of actin tail formation upon ectopic expression of WIP mutants led to the suggestion that WIP is required for this process. Similar studies of WIP mutants, however, did not affect the ability of EPEC to form actin pedestals, arguing against an essential role for WIP in EPEC-induced actin assembly. In this study, we demonstrate that Nck and N-WASP are normally recruited by vaccinia virus and EPEC in the absence of WIP, and neither WIP nor the WIP family members CR16 and WIRE/WICH are essential for pathogen induced actin assembly. In addition, although Nck binds EPEC Tir directly, N-WASP is required for its localization during pedestal formation. Overall, these data highlight similar pathogenic strategies shared by EPEC and vaccinia virus by demonstrating a requirement for both Nck and N-WASP, but not WIP or WIP family members in pathogen-induced actin assembly.
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Actinas/metabolismo , Proteínas de Transporte/metabolismo , Escherichia coli Enteropatogênica/patogenicidade , Vaccinia virus/patogenicidade , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Células Cultivadas , Proteínas do Citoesqueleto , Escherichia coli Enteropatogênica/metabolismo , Fibroblastos , Camundongos , Camundongos Knockout , Proteínas Oncogênicas/metabolismo , Vaccinia virus/metabolismo , Proteína Neuronal da Síndrome de Wiskott-Aldrich/metabolismoRESUMO
Upon infection of mammalian cells, enterohemorrhagic E. coli (EHEC) O157:H7 utilizes a type III secretion system to translocate the effectors Tir and EspF(U) (aka TccP) that trigger the formation of F-actin-rich 'pedestals' beneath bound bacteria. EspF(U) is localized to the plasma membrane by Tir and binds the nucleation-promoting factor N-WASP, which in turn activates the Arp2/3 actin assembly complex. Although N-WASP has been shown to be required for EHEC pedestal formation, the precise steps in the process that it influences have not been determined. We found that N-WASP and actin assembly promote EHEC-mediated translocation of Tir and EspF(U) into mammalian host cells. When we utilized the related pathogen enteropathogenic E. coli to enhance type III translocation of EHEC Tir and EspF(U), we found surprisingly that actin pedestals were generated on N-WASP-deficient cells. Similar to pedestal formation on wild type cells, Tir and EspF(U) were the only bacterial effectors required for pedestal formation, and the EspF(U) sequences required to interact with N-WASP were found to also be essential to stimulate this alternate actin assembly pathway. In the absence of N-WASP, the Arp2/3 complex was both recruited to sites of bacterial attachment and required for actin assembly. Our results indicate that actin assembly facilitates type III translocation, and reveal that EspF(U), presumably by recruiting an alternate host factor that can signal to the Arp2/3 complex, exhibits remarkable versatility in its strategies for stimulating actin polymerization.
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Actinas/metabolismo , Escherichia coli Êntero-Hemorrágica/metabolismo , Infecções por Escherichia coli/metabolismo , Proteína Neuronal da Síndrome de Wiskott-Aldrich/metabolismo , Animais , Proteínas de Transporte/metabolismo , Escherichia coli Êntero-Hemorrágica/patogenicidade , Proteínas de Escherichia coli/metabolismo , Técnicas de Inativação de Genes , Humanos , Immunoblotting , Peptídeos e Proteínas de Sinalização Intracelular , Camundongos , Microscopia de Fluorescência , Transporte Proteico/fisiologia , Receptores de Superfície Celular/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/fisiologiaRESUMO
Although HIV in the Middle East and North Africa is currently characterized as a low seroprevalence epidemic, there are numerous factors that are present in the region that could prevent-or exacerbate-the epidemic. The time to invest substantially in prevention-and gender-specific prevention in particular-is now. Given that most policy makers do not make gender-specific plans as epidemics progress, our research team-which draws upon expertise from both within and outside the region-worked together to make programmatic and policy suggestions in the Middle East and North Africa region in 5 key areas: (1) gender-specific and gender transformative HIV prevention interventions; (2) access to quality education and improvements in life skills and sex education; (3) economic empowerment; (4) property rights; and (5) antiviolence. In short, this work builds upon many ongoing efforts in the region and elucidates some of the links between gendered empowerment and health outcomes around the world, particularly HIV and AIDS.