RESUMO
Zika virus (ZIKV), a mosquito-borne flavivirus, causes devastating congenital birth defects. We isolated a human monoclonal antibody (mAb), ZKA190, that potently cross-neutralizes multi-lineage ZIKV strains. ZKA190 is highly effective in vivo in preventing morbidity and mortality of ZIKV-infected mice. NMR and cryo-electron microscopy show its binding to an exposed epitope on DIII of the E protein. ZKA190 Fab binds all 180 E protein copies, altering the virus quaternary arrangement and surface curvature. However, ZIKV escape mutants emerged in vitro and in vivo in the presence of ZKA190, as well as of other neutralizing mAbs. To counter this problem, we developed a bispecific antibody (FIT-1) comprising ZKA190 and a second mAb specific for DII of E protein. In addition to retaining high in vitro and in vivo potencies, FIT-1 robustly prevented viral escape, warranting its development as a ZIKV immunotherapy.
Assuntos
Anticorpos Monoclonais/uso terapêutico , Anticorpos Neutralizantes/uso terapêutico , Anticorpos Antivirais/uso terapêutico , Infecção por Zika virus/terapia , Zika virus/química , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/química , Anticorpos Neutralizantes/administração & dosagem , Anticorpos Neutralizantes/química , Anticorpos Antivirais/administração & dosagem , Anticorpos Antivirais/química , Microscopia Crioeletrônica , Epitopos , Humanos , Espectroscopia de Ressonância Magnética , Camundongos , Modelos Moleculares , Alinhamento de Sequência , Proteínas do Envelope Viral/química , Zika virus/imunologiaRESUMO
BACKGROUND: The largest West African monkeypox outbreak began September 2017, in Nigeria. Four individuals traveling from Nigeria to the United Kingdom (n = 2), Israel (n = 1), and Singapore (n = 1) became the first human monkeypox cases exported from Africa, and a related nosocomial transmission event in the United Kingdom became the first confirmed human-to-human monkeypox transmission event outside of Africa. METHODS: Epidemiological and molecular data for exported and Nigerian cases were analyzed jointly to better understand the exportations in the temporal and geographic context of the outbreak. RESULTS: Isolates from all travelers and a Bayelsa case shared a most recent common ancestor and traveled to Bayelsa, Delta, or Rivers states. Genetic variation for this cluster was lower than would be expected from a random sampling of genomes from this outbreak, but data did not support direct links between travelers. CONCLUSIONS: Monophyly of exportation cases and the Bayelsa sample, along with the intermediate levels of genetic variation, suggest a small pool of related isolates is the likely source for the exported infections. This may be the result of the level of genetic variation present in monkeypox isolates circulating within the contiguous region of Bayelsa, Delta, and Rivers states, or another more restricted, yet unidentified source pool.
Assuntos
Monkeypox virus , Mpox , Surtos de Doenças , Humanos , Mpox/epidemiologia , Monkeypox virus/genética , Nigéria/epidemiologia , Reino UnidoRESUMO
Addressing climate change risks requires collaboration and engagement across all sectors of society. In particular, effective partnerships are needed between research scientists producing new knowledge, policy-makers and practitioners who apply conservation actions on the ground. We describe the implementation of a model for increasing the application and useability of biodiversity research in climate adaptation policy and practice. The focus of the program was to increase the ability of a state government agency and natural resource practitioners in Australia to manage and protect biodiversity in a changing climate. The model comprised a five-stage process for enhancing impact (i) initiation of research projects that addressed priority conservation policy and management issues; (ii) co-design of the research using a collaborative approach involving multiple stakeholders; (iii) implementation of the research and design of decision tools and web-based resources; (iv) collaborative dissemination of the tools and resources via government and community working groups; and (v) evaluation of research impact. We report on the model development and implementation, and critically reflect on the model's impact. We share the lessons learnt from the challenges of operating within a stakeholder group with diverse objectives and criteria for success, and provide a template for creating an environmental research program with real world impact.
Assuntos
Biodiversidade , Recursos Naturais , Mudança Climática , Conservação dos Recursos Naturais , PolíticasRESUMO
Type I interferon receptor knockout mice (strain A129) were assessed as a disease model of hantavirus infection. A range of infection routes (intramuscular, intraperitoneal and intranasal) were assessed using minimally passaged Seoul virus (strain Humber). Dissemination of virus to the spleen, kidney and lung was observed at 5 days after intramuscular and intraperitoneal challenge, which was resolved by day 14. In contrast, intranasal challenge of A129 mice demonstrated virus tropism to the lung, which was maintained to day 14 post-challenge. These data support the use of the A129 mouse model for future infection studies and the in vivo evaluation of interventions.
Assuntos
Modelos Animais de Doenças , Infecções por Hantavirus , Orthohantavírus/fisiologia , Animais , Orthohantavírus/isolamento & purificação , Orthohantavírus/patogenicidade , Infecções por Hantavirus/patologia , Infecções por Hantavirus/virologia , Febre Hemorrágica com Síndrome Renal/patologia , Febre Hemorrágica com Síndrome Renal/virologia , Rim/virologia , Fígado/patologia , Pulmão/patologia , Pulmão/virologia , Masculino , Camundongos , Camundongos Knockout , RNA Viral/análise , RNA Viral/sangue , Receptor de Interferon alfa e beta/genética , Baço/patologia , Baço/virologia , Tropismo ViralRESUMO
Zika virus (ZIKV) is phylogenetically divided into two lineages comprising African (ZIKVAF) and Asian (ZIKVAS) genotypes. In the type-I interferon receptor deficient mouse model, ZIKVAF causes severe disease with all mice meeting humane endpoints with doses as low as 10 plaque-forming units (pfu) whereas a much milder infection is seen after challenge with ZIKVAS, including with doses as high as 106 pfu. Using this mouse model, the elucidation of cytokine, chemokine, growth factor and acute phase protein responses over the course of infection were studied to determine whether these analytes contributed to the stark difference in clinical outcome. Results demonstrated some significant differences, with the ZIKVAF infection being associated with increases in a higher number of biomarkers than ZIKVAS. When low (10 pfu) and high (106 pfu) challenge doses were compared, animals given the lower virus inoculum showed a wider range of responses, indicating a different disease progression compared to those challenged with high doses. These results aid with elucidating the different outcomes with the two lineages of ZIKV and with future work to assess pathogenicity of virus infection.
Assuntos
Proteínas de Fase Aguda/metabolismo , Quimiocinas/sangue , Citocinas/sangue , Peptídeos e Proteínas de Sinalização Intercelular/sangue , Infecção por Zika virus/metabolismo , Zika virus/patogenicidade , Animais , Quimiocinas/metabolismo , Citocinas/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Inflamação/metabolismo , Inflamação/virologia , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Masculino , Camundongos , Receptor de Interferon alfa e beta/deficiência , Receptor de Interferon alfa e beta/genética , Receptor de Interferon alfa e beta/metabolismo , Infecção por Zika virus/fisiopatologia , Infecção por Zika virus/virologiaRESUMO
In the UK, research on hazard group 4 (HG4) pathogens requires specialised Containment Level 4 (CL4) facilities. These differ from Biosafety Level 4 (BSL4) conditions in that work is conducted in class III microbiological safety cabinets for primary containment instead of using positive pressure suits. This presents unique challenges associated with the physical restrictions of working in a limited space, and prohibits the use of many techniques and specialist equipment. In consequence, detailed studies on the biology of HG4 pathogens and in particular their immunological relationships with the host are understudied in the UK; for example, the majority of immunological assays with which the immune system is interrogated require specialist equipment that is unsuitable for CL4. Multiplexing to simultaneously measure multiple analytes is increasingly being used in immunological studies. This assay is attractive for CL4 work because it reduces the time spent in the laboratory whilst maximising the use of valuable sample volume. The Luminex microsphere approach allows for the determination of many cytokines and chemokines, however, the detection system uses fixed aligned lasers and integrated computer systems which are unsuitable for use at CL4. Therefore, we have developed an approach in which the Luminex assay is conducted within the CL4 laboratory and a formalin-fixation stage is introduced to allow for analysis to be undertaken outside of containment. Quality control preparations allow the assay characteristics to be monitored and analysis of assay performance to be evaluated. Our data demonstrate that Luminex is an applicable tool for use at CL4 and that assays can be run reliably to generate reproducible standardised data across different plates and individual experiments.
Assuntos
Contenção de Riscos Biológicos/normas , Ensaios de Triagem em Larga Escala/instrumentação , Laboratórios/normas , Microbiologia/normas , Microesferas , Serviços de Laboratório Clínico , Doenças Transmissíveis/diagnóstico , Doenças Transmissíveis/microbiologia , Fixadores/química , Formaldeído/química , Ensaios de Triagem em Larga Escala/métodos , Ensaios de Triagem em Larga Escala/normas , Humanos , Controle de Qualidade , Reprodutibilidade dos Testes , Fixação de Tecidos/métodos , Fixação de Tecidos/normasRESUMO
Zika virus RNA has been detected in semen samples collected <370 days after symptom onset. We report unusual persistence of Zika virus RNA in semen, confirmed by sequencing at 515 days after symptom onset and detectable for >900 days, in a patient with immunosuppression.
Assuntos
Hospedeiro Imunocomprometido , Sêmen/virologia , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/virologia , Zika virus/classificação , Zika virus/genética , Antirreumáticos/efeitos adversos , Antirreumáticos/uso terapêutico , Biópsia , Doenças Transmissíveis Importadas/diagnóstico , Doenças Transmissíveis Importadas/epidemiologia , Doenças Transmissíveis Importadas/transmissão , Doenças Transmissíveis Importadas/virologia , Feminino , Humanos , Imunossupressores/efeitos adversos , Imunossupressores/uso terapêutico , Masculino , RNA Viral , Doenças Reumáticas/complicações , Doenças Reumáticas/diagnóstico , Doenças Reumáticas/tratamento farmacológico , Doença Relacionada a Viagens , Carga Viral , Infecção por Zika virus/diagnóstico , Infecção por Zika virus/transmissãoRESUMO
Brain death is associated with significant inflammation within the kidneys, which may contribute to reduced graft survival. Direct peritoneal resuscitation (DPR) has been shown to reduce systemic inflammation after brain death. To determine its effects, brain dead rats were resuscitated with normal saline (targeted intravenous fluid) to maintain a mean arterial pressure of 80 mmHg; DPR animals also received 30 cc of intraperitoneal peritoneal dialysis solution. Rats were euthanized at 0, 2, 4, and 6 h after brain death. Pro-inflammatory cytokines were measured using ELISA. Levels of IL-1ß, TNF-α, and IL-6 in the kidney were significantly increased as early as 2 h after brain death and significantly decreased with DPR. Levels of leukocyte adhesion molecules ICAM and VCAM increased after brain death and were decreased with DPR (ICAM 2.33 ± 0.14 vs. 0.42 ± 0.04, P = 0.002; VCAM 82.6 ± 5.8 vs. 37.3 ± 1.9, P = 0.002 at 4 h) as were E-selectin and P-selectin (E-selectin 25,605 vs. 16,144, P = 0.005; P-selectin 82.5 ± 3.3 vs. 71.0 ± 2.3, P = 0.009 at 4 h). Use of DPR reduces inflammation and adhesion molecule expression in the kidneys, and is associated with reduced macrophages and neutrophils on immunohistochemistry. Using DPR in brain dead donors has the potential to reduce the immunologic activity of transplanted kidneys and could improve graft survival.
Assuntos
Morte Encefálica , Soluções para Diálise/administração & dosagem , Hidratação/métodos , Rim/metabolismo , Ressuscitação/métodos , Solução Salina/administração & dosagem , Doença Aguda , Animais , Pressão Arterial , Moléculas de Adesão Celular/metabolismo , Citocinas/metabolismo , Modelos Animais de Doenças , Frequência Cardíaca , Mediadores da Inflamação/metabolismo , Infusões Intravenosas , Injeções Intraperitoneais , Rim/patologia , Macrófagos/metabolismo , Masculino , Nefrite/etiologia , Nefrite/metabolismo , Nefrite/patologia , Nefrite/fisiopatologia , Infiltração de Neutrófilos , Neutrófilos/metabolismo , Ratos Sprague-Dawley , Transdução de Sinais , Fatores de TempoRESUMO
Conventional resuscitation (CR) of hemorrhagic shock (HS), a significant cause of trauma mortality, is intravenous blood and fluids. CR restores central hemodynamics, but vital organ flow can drop, causing hypoperfusion, hypoxia, damage-associated molecular patterns (DAMPs), and remote organ dysfunction (i.e., lung). CR plus direct peritoneal resuscitation (DPR) prevents intestinal and hepatic hypoperfusion. We hypothesized that DPR prevents lung injury in HS/CR by altering DAMPs. Anesthetized male Sprague-Dawley rats were randomized to groups ( n = 8/group) in one of two sets: 1) sham (no HS, CR, or DPR), 2) HS/CR (HS = 40% mean arterial pressure (MAP) for 60 min, CR = shed blood + 2 volumes normal saline), or 3) HS/CR + DPR. The first set underwent whole lung blood flow by colorimetric microspheres. The second set underwent tissue collection for Luminex, ELISAs, and histopathology. Lipopolysaccharide (LPS) and DAMPs were measured in serum and/or lung, including cytokines, hyaluronic acid (HA), high-mobility group box 1 (HMGB1), Toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 protein (MYD88), and TIR-domain-containing adapter-inducing interferon-ß (TRIF). Statistics were by ANOVA and Tukey-Kramer test with a priori P < 0.05. HS/CR increased serum LPS, HA, HMGB1, and some cytokines [interleukin (IL)-1α, IL-1ß, IL-6, and interferon-γ]. Lung TLR4 and MYD88 were increased but not TRIF compared with Shams. HS/CR + DPR decreased LPS, HA, cytokines, HMGB1, TLR4, and MYD88 levels but did not alter TRIF compared with HS/CR. The data suggest that gut-derived DAMPs can be modulated by adjunctive DPR to prevent activation of lung TLR-4-mediated processes. Also, DPR improved lung blood flow and reduced lung tissue injury. Adjunctive DPR in HS/CR potentially improves morbidity and mortality by downregulating the systemic DAMP response.
Assuntos
Hidratação , Lesão Pulmonar/prevenção & controle , Ressuscitação , Choque Hemorrágico/terapia , Animais , Pressão Sanguínea , Citocinas/metabolismo , Modelos Animais de Doenças , Proteína HMGB1/metabolismo , Lesão Pulmonar/metabolismo , Lesão Pulmonar/patologia , Lesão Pulmonar/fisiopatologia , Masculino , Fator 88 de Diferenciação Mieloide/metabolismo , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Choque Hemorrágico/metabolismo , Choque Hemorrágico/patologia , Choque Hemorrágico/fisiopatologia , Receptor 4 Toll-Like/metabolismoRESUMO
The sudden and explosive expansion of Zika virus (ZIKV) from the African continent through Oceania and culminating in the outbreak in South America has highlighted the importance of new rapid point-of-care diagnostic tools for the control and prevention of transmission. ZIKV infection has devastating consequences, such as neurological congenital malformations in infants born to infected mothers and Guillain-Barré syndrome in adults. Additionally, its potential for transmission through vector bites, as well as from person to person through blood transfusions and sexual contact, are important considerations for prompt diagnosis. Recombinase polymerase amplification (RPA), an isothermal method, was developed as an alternative field-applicable assay to PCR. Here we report the development of a novel ZIKV real-time reverse transcriptase RPA (RT-RPA) assay capable of detecting a range of different ZIKV strains from a variety of geographical locations. The ZIKV RT-RPA was shown to be highly sensitive, being capable of detecting as few as five copies of target nucleic acid per reaction, and suitable for use with a battery-operated portable device. The ZIKV RT-RPA demonstrated 100â% specificity and 83â% sensitivity in clinical samples. Furthermore, we determined that the ZIKV RT-RPA is a versatile assay that can be applied to crude samples, such as saliva and serum, and can be used as a vector surveillance tool on crude mosquito homogenates. Therefore, the developed ZIKV RT-RPA is a useful diagnostic tool that can be transferred to a resource-limited location, eliminating the need for a specialized and sophisticated laboratory environment and highly trained staff.
Assuntos
Zika virus/isolamento & purificação , Animais , Sequência Conservada , Culicidae/virologia , Variação Genética , Técnicas de Amplificação de Ácido Nucleico , Sistemas Automatizados de Assistência Junto ao Leito , RNA Viral/genética , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Cardiac pacemaking is governed by specialized cardiomyocytes located in the sinoatrial node (SAN). SAN cells (SANCs) integrate voltage-gated currents from channels on the membrane surface (membrane clock) with rhythmic Ca(2+) release from internal Ca(2+) stores (Ca(2+) clock) to adjust heart rate to meet hemodynamic demand. Here, we report that stromal interaction molecule 1 (STIM1) and Orai1 channels, key components of store-operated Ca(2+) entry, are selectively expressed in SANCs. Cardiac-specific deletion of STIM1 in mice resulted in depletion of sarcoplasmic reticulum (SR) Ca(2+) stores of SANCs and led to SAN dysfunction, as was evident by a reduction in heart rate, sinus arrest, and an exaggerated autonomic response to cholinergic signaling. Moreover, STIM1 influenced SAN function by regulating ionic fluxes in SANCs, including activation of a store-operated Ca(2+) current, a reduction in L-type Ca(2+) current, and enhancing the activities of Na(+)/Ca(2+) exchanger. In conclusion, these studies reveal that STIM1 is a multifunctional regulator of Ca(2+) dynamics in SANCs that links SR Ca(2+) store content with electrical events occurring in the plasma membrane, thereby contributing to automaticity of the SAN.
Assuntos
Canais de Cálcio/metabolismo , Sinalização do Cálcio/fisiologia , Cálcio/metabolismo , Miócitos Cardíacos/metabolismo , Retículo Sarcoplasmático/metabolismo , Nó Sinoatrial/metabolismo , Animais , Canais de Cálcio/genética , Canais de Cálcio Tipo L/genética , Canais de Cálcio Tipo L/metabolismo , Camundongos , Camundongos Knockout , Miócitos Cardíacos/citologia , Proteína ORAI1 , Retículo Sarcoplasmático/genética , Nó Sinoatrial/citologia , Molécula 1 de Interação EstromalRESUMO
To support the licensure of a new and safer vaccine to protect people against smallpox, a monkeypox model of infection in cynomolgus macaques, which simulates smallpox in humans, was used to evaluate two vaccines, Acam2000 and Imvamune, for protection against disease. Animals vaccinated with a single immunization of Imvamune were not protected completely from severe and/or lethal infection, whereas those receiving either a prime and boost of Imvamune or a single immunization with Acam2000 were protected completely. Additional parameters, including clinical observations, radiographs, viral load in blood, throat swabs, and selected tissues, vaccinia virus-specific antibody responses, immunophenotyping, extracellular cytokine levels, and histopathology were assessed. There was no significant difference (P > 0.05) between the levels of neutralizing antibody in animals vaccinated with a single immunization of Acam2000 (132 U/ml) and the prime-boost Imvamune regime (69 U/ml) prior to challenge with monkeypox virus. After challenge, there was evidence of viral excretion from the throats of 2 of 6 animals in the prime-boost Imvamune group, whereas there was no confirmation of excreted live virus in the Acam2000 group. This evaluation of different human smallpox vaccines in cynomolgus macaques helps to provide information about optimal vaccine strategies in the absence of human challenge studies.
Assuntos
Imunização/métodos , Orthopoxvirus/imunologia , Infecções por Poxviridae/prevenção & controle , Vacina Antivariólica/farmacologia , Animais , Anticorpos Neutralizantes/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Macaca fascicularis , Masculino , Reação em Cadeia da Polimerase em Tempo Real , Vacinas Atenuadas/farmacologia , Eliminação de Partículas Virais/imunologiaRESUMO
Crimean-Congo Haemorrhagic Fever Virus (CCHFV) is spread by infected ticks or direct contact with blood, tissues and fluids from infected patients or livestock. Infection with CCHFV causes severe haemorrhagic fever in humans which is fatal in up to 83 % of cases. CCHFV is listed as a priority pathogen by the World Health Organization (WHO) and there are currently no widely-approved vaccines. Defining a serological correlate of protection against CCHFV infection would support the development of vaccines by providing a 'target threshold' for pre-clinical and clinical immunogenicity studies to achieve in subjects and potentially obviate the need for in vivo protection studies. We therefore sought to establish titratable protection against CCHFV using pooled human convalescent plasma, in a mouse model. Convalescent plasma collected from seven individuals with a known previous CCHFV virus infection were characterised using binding antibody and neutralisation assays. All plasma recognised nucleoprotein and the Gc glycoprotein, but some had a lower Gn glycoprotein response by ELISA. Pooled plasma and two individual donations from convalescent donors were administered intraperitoneally to A129 mice 24 h prior to intradermal challenge with CCHFV (strain IbAr10200). A partial protective effect was observed with all three convalescent plasmas characterised by longer survival post-challenge and reduced clinical score. These protective responses were titratable. Further characterisation of the serological reactivities within these samples will establish their value as reference materials to support assay harmonisation and accelerate vaccine development for CCHFV.
Assuntos
Anticorpos Neutralizantes , Anticorpos Antivirais , Modelos Animais de Doenças , Vírus da Febre Hemorrágica da Crimeia-Congo , Febre Hemorrágica da Crimeia , Animais , Febre Hemorrágica da Crimeia/imunologia , Febre Hemorrágica da Crimeia/prevenção & controle , Camundongos , Vírus da Febre Hemorrágica da Crimeia-Congo/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Humanos , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Feminino , Testes de Neutralização , Plasma/imunologia , MasculinoRESUMO
RATIONALE: Fibroblast growth factor homologous factors (FHFs), a subfamily of fibroblast growth factors (FGFs) that are incapable of functioning as growth factors, are intracellular modulators of Na(+) channels and have been linked to neurodegenerative diseases. Although certain FHFs have been found in embryonic heart, they have not been reported in adult heart, and they have not been shown to regulate endogenous cardiac Na(+) channels or to participate in cardiac pathophysiology. OBJECTIVE: We tested whether FHFs regulate Na(+) channels in murine heart. METHODS AND RESULTS: We demonstrated that isoforms of FGF13 are the predominant FHFs in adult mouse ventricular myocytes. FGF13 binds directly to, and colocalizes with, the Na(V)1.5 Na(+) channel in the sarcolemma of adult mouse ventricular myocytes. Knockdown of FGF13 in adult mouse ventricular myocytes revealed a loss of function of Na(V)1.5-reduced Na(+) current density, decreased Na(+) channel availability, and slowed Na(V)1.5-reduced Na(+) current recovery from inactivation. Cell surface biotinylation experiments showed ≈45% reduction in Na(V)1.5 protein at the sarcolemma after FGF13 knockdown, whereas no changes in whole-cell Na(V)1.5 protein or in mRNA level were observed. Optical imaging in neonatal rat ventricular myocyte monolayers demonstrated slowed conduction velocity and a reduced maximum capture rate after FGF13 knockdown. CONCLUSION: These findings show that FHFs are potent regulators of Na(+) channels in adult ventricular myocytes and suggest that loss-of-function mutations in FHFs may underlie a similar set of cardiac arrhythmias and cardiomyopathies that result from Na(V)1.5 loss-of-function mutations.
Assuntos
Fatores de Crescimento de Fibroblastos/metabolismo , Ventrículos do Coração/metabolismo , Ativação do Canal Iônico , Miócitos Cardíacos/metabolismo , Canais de Sódio/metabolismo , Sódio/metabolismo , Potenciais de Ação , Animais , Animais Recém-Nascidos , Biotinilação , Células Cultivadas , Fatores de Crescimento de Fibroblastos/genética , Cinética , Camundongos , Camundongos Endogâmicos C57BL , Mutação , Canal de Sódio Disparado por Voltagem NAV1.5 , Técnicas de Patch-Clamp , Ligação Proteica , Interferência de RNA , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Sarcolema/metabolismo , Canais de Sódio/genética , Transfecção , Imagens com Corantes Sensíveis à VoltagemRESUMO
During muscle development, the sarco/endoplasmic reticulum (SR/ER) undergoes remodeling to establish a specialized internal Ca(2+) store for muscle contraction. We hypothesized that store operated Ca(2+) entry (SOCE) is required to fill Ca(2+) stores and is, therefore, critical to creating a mature SR/ER. Stromal interaction molecule 1 (STIM1) functions as a sensor of internal Ca(2+) store content and an activator of SOCE channels. Myocytes lacking STIM1 display reduced SR Ca(2+) content and altered expression of key SR proteins. Sarcolipin (SLN), an inhibitor of the SR calcium pump, was markedly increased in the muscle of mutant STIM1 mice. SLN opposes the actions of STIM1 by limiting SOCE, reducing SR Ca(2+) content and delaying muscle differentiation. During mouse muscle development SLN is highly expressed in embryonic muscle, while the expression of STIM1 is up-regulated postnatally. These results suggest that SOCE regulates SR/ER specialization and that SLN and STIM1 act in opposing fashions to govern SOCE during myogenesis.
Assuntos
Cálcio/fisiologia , Retículo Endoplasmático/fisiologia , Glicoproteínas de Membrana/fisiologia , Desenvolvimento Muscular , Proteínas Musculares/fisiologia , Proteolipídeos/fisiologia , Animais , Canais de Cálcio , Sinalização do Cálcio , Diferenciação Celular , Células Cultivadas , Regulação da Expressão Gênica no Desenvolvimento , Camundongos , Músculo Esquelético/citologia , Músculo Esquelético/fisiologia , Molécula 1 de Interação EstromalRESUMO
Cardiomyocytes in the sinoatrial node (SAN) are specialized to undergo spontaneous diastolic depolarization (DD) to create action potentials (AP) that serve as the origin of the heartbeat. Two cellular clocks govern DD: the membrane clock where ion channels contribute ionic conductance to create DD and the Ca 2+ clock where rhythmic Ca 2+ release from sarcoplasmic reticulum (SR) during diastole contributes pacemaking. How the membrane and Ca 2+ clocks interact to synchronize and drive DD is not well understood. Here, we identified stromal interaction molecule 1 (STIM1), the activator of store operated Ca 2+ entry (SOCE), in the P-cell cardiomyocytes of the SAN. Functional studies from STIM1 KO mice reveal dramatic changes in properties of AP and DD. Mechanistically, we show that STIM1 regulates the funny currents and HCN4 channels that are required to initiate DD and maintain sinus rhythm in mice. Taken together, our studies suggest that STIM1 acts as a sensor for both the Ca 2+ and membrane clocks for mouse SAN for cardiac pacemaking.
RESUMO
Humanised antibodies targeting Crimean-Congo Haemorrhagic virus (CCHFV) are needed for the development and standardisation of serological assays. These assays are needed to address a shortfall in available tests that meet regulatory diagnostic standards and to aid surveillance activities to extend knowledge on the distribution of CCHFV. To generate a humanised monoclonal antibody against CCHFV, we have compared two methods: the traditional mouse hybridoma approach with subsequent sequencing and humanisation of antibodies versus a non-animal alternative using a human combinatorial antibody library (HuCAL). Our results demonstrated that the mouse hybridoma followed by humanisation protocol gave higher affinity antibodies. Whilst not yet able to demonstrate the generation of equivalent humanised antibodies without the use of animals, sequencing data enables the subsequent production of recombinant antibodies, thus providing a reduction in future animal usage for this application. Ultimately, our report provides information on development of a humanised standardised control, which can form an important positive control component of serological assays against CCHFV.
Assuntos
Vírus da Febre Hemorrágica da Crimeia-Congo , Febre Hemorrágica da Crimeia , Humanos , Animais , Camundongos , Febre Hemorrágica da Crimeia/diagnóstico , Febre Hemorrágica da Crimeia/epidemiologia , Hibridomas , Anticorpos Antivirais , Imunoglobulina GRESUMO
Nipah virus (NiV) is an emerging pathogen that can cause severe respiratory illness and encephalitis in humans. The main reservoir is fruit bats, distributed across a large geographical area that includes Australia, Southeast Asia, and Africa. Incursion into humans is widely reported through exposure of infected pigs, ingestion of contaminated food, or through contact with an infected person. With no approved treatments or vaccines, NiV poses a threat to human public health and has epidemic potential. To aid with the assessment of emerging interventions being developed, an expansion of preclinical testing capability is required. Given variations in the model parameters observed in different sites during establishment, optimisation of challenge routes and doses is required. Upon evaluating the hamster model, an intranasal route of challenge was compared with intraperitoneal delivery, demonstrating a more rapid dissemination to wider tissues in the latter. A dose effect was observed between those causing respiratory illness and those resulting in neurological disease. The data demonstrate the successful establishment of the hamster model of NiV disease for subsequent use in the evaluation of vaccines and antivirals.
RESUMO
The emergence of severe acute respiratory syndrome coronavirus (SARS-CoV-2) and its expansion to a worldwide pandemic resulted in efforts to assess and develop interventions to reduce the disease burden. Despite the introduction of vaccine programmes against SARS-CoV-2, global incidence levels in early 2022 remained high, demonstrating a need for the development of physiologically relevant models, which are essential for the identification of alternative antiviral strategies. The hamster model of SARS-CoV-2 infection has been widely adopted due to similarities with humans in terms of host cell entry mechanism (via ACE2), and aspects of symptomology and virus shedding. We have previously described a natural transmission hamster model that better represents the natural course of infection. In the present study, we have conducted further testing of the model using the first-in-class antiviral Neumifil, which has previously shown promise against SARS-CoV-2 after a direct intranasal challenge. Neumifil is an intranasally delivered carbohydrate-binding module (CBM) which reduces the binding of viruses to their cellular receptor. By targeting the host cell, Neumifil has the potential to provide broad protection against multiple pathogens and variants. This study demonstrates that using a combination of a prophylactic and therapeutic delivery of Neumifil significantly reduces the severity of clinical signs in animals infected via a natural route of transmission and indicates a reduction of viral loads in the upper respiratory tract. Further refinements of the model are required in order to ensure the adequate transmission of the virus. However, our results provide additional data to the evidence base of Neumifil efficacy against respiratory virus infection and demonstrate that the transmission model is a potentially valuable tool for testing antiviral compounds against SARS-CoV-2.
Assuntos
COVID-19 , SARS-CoV-2 , Animais , Cricetinae , Humanos , SARS-CoV-2/metabolismo , Antivirais/farmacologia , Antivirais/uso terapêutico , Antivirais/química , CarboidratosRESUMO
BACKGROUND: The tick-borne bunyavirus, Crimean-Congo Haemorrhagic Fever virus (CCHFV), can cause severe febrile illness in humans and has a wide geographic range that continues to expand due to tick migration. Currently, there are no licensed vaccines against CCHFV for widespread usage. METHODS: In this study, we describe the preclinical assessment of a chimpanzee adenoviral vectored vaccine (ChAdOx2 CCHF) which encodes the glycoprotein precursor (GPC) from CCHFV. FINDINGS: We demonstrate here that vaccination with ChAdOx2 CCHF induces both a humoral and cellular immune response in mice and 100% protection in a lethal CCHF challenge model. Delivery of the adenoviral vaccine in a heterologous vaccine regimen with a Modified Vaccinia Ankara vaccine (MVA CCHF) induces the highest levels of CCHFV-specific cell-mediated and antibody responses in mice. Histopathological examination and viral load analysis of the tissues of ChAdOx2 CCHF immunised mice reveals an absence of both microscopic changes and viral antigen associated with CCHF infection, further demonstrating protection against disease. INTERPRETATION: There is the continued need for an effective vaccine against CCHFV to protect humans from lethal haemorrhagic disease. Our findings support further development of the ChAd platform expressing the CCHFV GPC to seek an effective vaccine against CCHFV. FUNDING: This research was supported by funding from the Biotechnology and Biological Sciences Research Council (UKRI-BBSRC) [BB/R019991/1 and BB/T008784/1].