Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Mais filtros

Tipo de documento
Intervalo de ano de publicação
2.
J Immunol ; 185(6): 3593-601, 2010 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-20693420

RESUMO

To deepen our knowledge of the natural host response to pathogens, our team undertook an in vivo screen of mutagenized 129S1 mice with Salmonella Typhimurium. One mutation affecting Salmonella susceptibility was mapped to a region of 1.3 Mb on chromosome 6 that contains 15 protein-coding genes. A missense mutation was identified in the Usp18 (ubiquitin-specific peptidase 18) gene. This mutation results in an increased inflammatory response (IL-6, type 1 IFN) to Salmonella and LPS challenge while paradoxically reducing IFN-gamma production during bacterial infection. Increased STAT1 phosphorylation correlated with impaired STAT4 phosphorylation, resulting in overwhelming IL-6 secretion but reduced IFN-gamma production during infection. The reduced IFN-gamma levels, along with the increased inflammation, rationalize the S. Typhimurium susceptibility in terms of increased bacterial load in target organs and cytokine-induced septic shock and death.


Assuntos
Endopeptidases/genética , Etilnitrosoureia/toxicidade , Interferon-alfa/fisiologia , Interferon beta/fisiologia , Interferon gama/antagonistas & inibidores , Mutação de Sentido Incorreto , Fator de Transcrição STAT4/antagonistas & inibidores , Salmonelose Animal/imunologia , Transdução de Sinais/imunologia , Animais , Endopeptidases/deficiência , Feminino , Predisposição Genética para Doença , Imunidade Inata/genética , Imunidade Inata/imunologia , Interferon gama/biossíntese , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Camundongos Knockout , Mutagênicos/toxicidade , Mutação de Sentido Incorreto/efeitos dos fármacos , Fosforilação/genética , Fosforilação/imunologia , Fator de Transcrição STAT4/metabolismo , Fator de Transcrição STAT4/fisiologia , Salmonelose Animal/genética , Salmonelose Animal/microbiologia , Salmonella typhimurium/imunologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Ubiquitina/imunologia , Ubiquitina Tiolesterase
3.
BMC Pediatr ; 12: 74, 2012 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-22708988

RESUMO

BACKGROUND: Despite its high incidence among children under the age of five, little is known about the burden of pediatric gastroenteritis outside the medical setting. The objective of this study was to describe the burden of acute gastroenteritis among children residing in the United Arab Emirates, including those not receiving medical care. METHODS: A quantitative cross-sectional survey of 500 parents of children under 5 years of age who had suffered from acute gastroenteritis the preceding three months was conducted in the cities of Abu Dhabi and Al Ain. Data collected included respondent characteristics, disease symptoms, medical care sought, and parental expenditures and work loss. Data were analyzed using parametric and non-parametric statistical methods. RESULTS: Vomiting and diarrhea episodes lasted on average between 3 and 4 days. Overall, 87% of parents sought medical care for their children; 10% of these cases required hospitalization with an average length of stay of 2.6 days. When medical care was sought, the average parental cost per gastroenteritis episode was US$64, 4.5 times higher than with home care only (US$14). Nearly 60% of this difference was attributable to co-payments and medication use: 69% of children used oral rehydration solution, 68% antiemetics, 65% antibiotics and 64% antidiarrheals. Overall, 38 parents missed work per 100 gastroenteritis episodes for an average of 1.4 days. CONCLUSIONS: Given its high incidence, pediatric gastroenteritis has an important financial and productivity impact on parents in the United Arab Emirates. To reduce this impact, efforts should be made both to prevent acute gastroenteritis and to optimize its treatment.


Assuntos
Efeitos Psicossociais da Doença , Gastroenterite/economia , Doença Aguda , Pré-Escolar , Estudos Transversais , Diarreia/economia , Diarreia/etiologia , Diarreia/terapia , Gastroenterite/complicações , Gastroenterite/diagnóstico , Gastroenterite/terapia , Gastos em Saúde/estatística & dados numéricos , Inquéritos Epidemiológicos , Hospitalização/economia , Hospitalização/estatística & dados numéricos , Humanos , Lactente , Recém-Nascido , Licença Parental/estatística & dados numéricos , Emirados Árabes Unidos , Vômito/economia , Vômito/etiologia , Vômito/terapia
4.
NPJ Microgravity ; 8(1): 58, 2022 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-36550172

RESUMO

Knowledge transfer among research disciplines can lead to substantial research progress. At first glance, astronaut health and rare diseases may be seen as having little common ground for such an exchange. However, deleterious health conditions linked to human space exploration may well be considered as a narrow sub-category of rare diseases. Here, we compare and contrast research and healthcare in the contexts of rare diseases and space health and identify common barriers and avenues of improvement. The prevalent genetic basis of most rare disorders contrasts sharply with the occupational considerations required to sustain human health in space. Nevertheless small sample sizes and large knowledge gaps in natural history are examples of the parallel challenges for research and clinical care in the context of both rare diseases and space health. The two areas also face the simultaneous challenges of evidence scarcity and the pressure to deliver therapeutic solutions, mandating expeditious translation of research knowledge into clinical care. Sharing best practices between these fields, including increasing participant involvement in all stages of research and ethical sharing of standardized data, has the potential to contribute to humankind's efforts to explore ever further into space while caring for people on Earth in a more inclusive fashion.

5.
Biomed Hub ; 5(3): 1341-1363, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33564668

RESUMO

"A ship in the harbour is safe, but that is not what ships are built for," observed that sage 19th century philosopher William Shedd. In other words, technology of high potential is of little value if the potential is not exploited. As the shape of 2020 is increasingly defined by the coronavirus pandemic, digitalisation is like a ship loaded with technology that has a huge capacity for transforming mankind's combat against infectious disease. But it is still moored safely in harbour. Instead of sailing bravely into battle, it remains at the dockside, cowering from the storm beyond the breakwaters. Engineers and fitters constantly fine-tune it, and its officers and deckhands perfect their operating procedures, but that promise is unfulfilled, restrained by the hesitancy and indecision of officialdom. Out there, the seas of the pandemic are turbulent and uncharted, and it is impossible to know in advance everything of the other dangers that may lurk beyond those cloudy horizons. However, the more noble course is for orders to be given to complete the preparations, to cast off and set sail, and to join other vessels crewed by valiant healthcare workers and tireless researchers, already deeply engaged in a rescue mission for the whole of the human race. It is the destiny of digitalisation to navigate those oceans alongside other members of that task force, and the hour of destiny has arrived. This article focuses on the potential enablers and recommendation to maximise learnings during the era of COVID-19.

6.
Biomed Hub ; 5(2): 15-67, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32775335

RESUMO

The scope and potential of personalised health care are underappreciated and underrealised, often because of resistance to change. The consequence is that many inadequacies of health care in Europe persist unnecessarily, and many opportunities for improvement are neglected. This article identifies the principal challenges, outlines possible approaches to resolving them, and highlights the benefits that could result from greater adoption of personalised health care. It locates the discussion in the context of European policy, focusing particularly on the most recent and authoritative reviews of health care in the EU Member States, and on the newly acquired spirit of readiness and pragmatism among European officials to embrace change and innovative technologies in a new decade. It highlights the attention now being given by policymakers to incentives, innovation, and investment as levers to improve European citizens' prospects in a rapidly evolving world, and how these distinct and disruptive themes contribute to a renaissance in thinking about delivering optimal health care in Europe. It explores the chances offered to patients by specific initiatives in health domains such as cancer and antimicrobial resistance, and by innovative science, novel therapies, earlier diagnosis tools, and deeper understanding of health promotion and prevention. And it reflects on how health care providers could benefit from a shift towards better primary care and towards deploying health data more effectively, including the use of artificial intelligence, coupled with a move to a smoother organisational/regulatory structure and realigned professional responsibilities. The conclusion is that preparing Europe's health care systems for the inevitable strains of the coming years is both possible and necessary. A more courageous approach to embracing personalised health care could guarantee the sustainability of Europe's health care systems before rising demands and exponential costs overwhelm them - an exercise in future-proofing, in ensuring that they are equipped to withstand whatever lies ahead. A focus on the potential and implementation of personalised care would permit more efficient use of resources and deliver better quality health-preserving care.

7.
Front Pediatr ; 8: 579924, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33381478

RESUMO

Advances in omics and specifically genomic technologies are increasingly transforming rare disease diagnosis. However, the benefits of these advances are disproportionately experienced within and between populations, with Indigenous populations frequently experiencing diagnostic and therapeutic inequities. The International Rare Disease Research Consortium (IRDiRC) multi-stakeholder partnership has been advancing toward the vision of all people living with a rare disease receiving an accurate diagnosis, care, and available therapy within 1 year of coming to medical attention. In order to further progress toward this vision, IRDiRC has created a taskforce to explore the access barriers to diagnosis of rare genetic diseases faced by Indigenous peoples, with a view of developing recommendations to overcome them. Herein, we provide an overview of the state of play of current barriers and considerations identified by the taskforce, to further stimulate awareness of these issues and the passage toward solutions. We focus on analyzing barriers to accessing genetic services, participating in genomic research, and other aspects such as concerns about data sharing, the handling of biospecimens, and the importance of capacity building.

9.
Biomed Hub ; 2(Suppl 1): 41-43, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-31988931

RESUMO

Personalized (or precision) medicine approaches are currently being introduced in healthcare delivery following the development of new technologies and of novel ways to integrate and analyze various data sources. This editorial describes the efforts invested since 2012 by the Canadian Institutes of Health Research (CIHR) to foster the development and implementation of personalized medicine in Canada. Success stories from past investments as well as future developments are presented from a Canadian perspective.

10.
Front Immunol ; 8: 498, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28507548

RESUMO

Retention of iron in tissue macrophages via upregulation of hepcidin (HAMP) and downregulation of the iron exporter ferroportin (FPN) is thought to participate in the establishment of anemia of inflammation after infection. However, an upregulation of FPN has been proposed to limit macrophages iron access to intracellular pathogens. Therefore, we studied the iron homeostasis and in particular the regulation of FPN after infection with Salmonella enterica serovar Typhimurium in mice presenting tissue macrophages with high iron (AcB61), basal iron (A/J and wild-type mice), or low iron (Hamp knock out, Hamp-/-) levels. The presence of iron in AcB61 macrophages due to extravascular hemolysis and strong erythrophagocytosis activity favored the proliferation of Salmonella in the spleen and liver with a concomitant decrease of FPN protein expression. Despite systemic iron overload, no or slight increase in Salmonella burden was observed in Hamp-/- mice compared to controls. Importantly, FPN expression at both mRNA and protein levels was strongly decreased during Salmonella infection in Hamp-/- mice. The repression of Fpn mRNA was also observed in Salmonella-infected cultured macrophages. In addition, the downregulation of FPN was associated with decreased iron stores in both the liver and spleen in infected mice. Our findings show that during Salmonella infection, FPN is repressed through an iron and hepcidin-independent mechanism. Such regulation likely provides the cellular iron indispensable for the growth of Salmonella inside the macrophages.

11.
Public Health Genomics ; 18(6): 372-80, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26565702

RESUMO

There is currently a rapid evolution of clinical practices based on the introduction of patient stratification and molecular diagnosis that is likely to improve health outcomes. Building on a strong research base, complemented by strong support from clinicians and health authorities, the oncology field is at the forefront of this evolution. Yet, clinical research is still facing many challenges that need to be addressed in order to conduct necessary studies and effectively translate medical breakthroughs based on personalized medicine into standards of care. Leveraging its universal health care system and on resources developed to support oncology clinical research, Canada is well positioned to join the international efforts deployed to address these challenges. Available resources include a broad range of structures and funding mechanisms, ranging from direct clinical trial support to post-marketing surveillance. Here, we propose a clinical model for the introduction of innovation for precision medicine in oncology that starts with patients' and clinicians' unmet needs to initiate a cycle of discovery, validation, translation and sustainability development.


Assuntos
Pesquisa Biomédica/tendências , Oncologia/tendências , Medicina de Precisão/métodos , Medicina de Precisão/tendências , Pesquisa Biomédica/economia , Canadá , Ensaios Clínicos como Assunto , Atenção à Saúde , Humanos , Oncologia/economia , Patologia Molecular , Pediatria , Medicina de Precisão/economia , Vigilância de Produtos Comercializados , Pesquisa Translacional Biomédica/economia , Pesquisa Translacional Biomédica/tendências
12.
Public Health Genomics ; 18(5): 249-59, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26316202

RESUMO

Scientific knowledge and our understanding of the human body and diseases have limited any possible treatment tailoring to each patient. The technological advances enabling the integration of various data sets (e.g. '-omics', microbiome, epigenetics and environmental exposure) have facilitated a greater understanding of the human body, the molecular basis of disease and all the factors influencing disease onset, progression and response to treatment, thereby ushering in the era of personalized medicine. We evaluate the regulatory approaches available to facilitate early patient access to efficacious and safe compounds in the EU and the USA in order to make more informed recommendations in the future as to the gaps in regulations for early patient access. An in-depth analysis of conditional approvals (EU) and accelerated approvals (USA) is performed based on the publicly available information (European public assessment reports and a summary review of products approved under both programmes). The types of product, indications, time to approval and type of evidence submitted were analysed. Between 2007 and early 2015, 17 products were conditionally approved in the EU and 25 in the USA, most of them in the area of oncology and based on evidence from phase II clinical trial data. Early approval of promising products based on data from early phases of development is already possible in the EU and the USA. Some of the improvements could entail implementing a rolling assessment of evidence in Europe and extending the scope of early dialogues.


Assuntos
Aprovação de Drogas/organização & administração , Descoberta de Drogas/legislação & jurisprudência , Acessibilidade aos Serviços de Saúde , Medicina de Precisão , Pesquisa Biomédica/economia , Pesquisa Biomédica/organização & administração , Ensaios Clínicos como Assunto , Análise Custo-Benefício , Aprovação de Drogas/economia , Aprovação de Drogas/métodos , Descoberta de Drogas/economia , Europa (Continente) , União Europeia , Previsões , Humanos , Marketing de Serviços de Saúde/economia , Marketing de Serviços de Saúde/legislação & jurisprudência , Marketing de Serviços de Saúde/organização & administração , Medição de Risco , Sociedades Médicas , Estados Unidos , United States Food and Drug Administration
13.
PLoS One ; 8(2): e55331, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23390527

RESUMO

Salmonella, a ubiquitous Gram-negative intracellular bacterium, is a food borne pathogen that infects a broad range of hosts. Infection with Salmonella Typhimurium in mice is a broadly recognized experimental model resembling typhoid fever in humans. Using a N-ethyl-N-nitrosurea (ENU) mutagenesis recessive screen, we report the identification of Ity16 (Immunity to Typhimurium locus 16), a locus responsible for increased susceptibility to infection. The position of Ity16 was refined on chromosome 8 and a nonsense mutation was identified in the ankyrin 1 (Ank1) gene. ANK1 plays an important role in the formation and stabilization of the red cell cytoskeleton. The Ank1(Ity16/Ity16) mutation causes severe hemolytic anemia in uninfected mice resulting in splenomegaly, hyperbilirubinemia, jaundice, extramedullary erythropoiesis and iron overload in liver and kidneys. Ank1(Ity16/Ity16) mutant mice demonstrated low levels of hepcidin (Hamp) expression and significant increases in the expression of the growth differentiation factor 15 (Gdf15), erythropoietin (Epo) and heme oxygenase 1 (Hmox1) exacerbating extramedullary erythropoiesis, tissue iron deposition and splenomegaly. As the infection progresses in Ank1(Ity16/Ity16), the anemia worsens and bacterial load were high in liver and kidneys compared to wild type mice. Heterozygous Ank1(+/Ity16) mice were also more susceptible to Salmonella infection although to a lesser extent than Ank1(Ity16/Ity16) and they did not inherently present anemia and splenomegaly. During infection, iron accumulated in the kidneys of Ank1(+/Ity16) mice where bacterial loads were high compared to littermate controls. The critical role of HAMP in the host response to Salmonella infection was validated by showing increased susceptibility to infection in Hamp-deficient mice and significant survival benefits in Ank1(+/Ity16) heterozygous mice treated with HAMP peptide. This study illustrates that the regulation of Hamp and iron balance are crucial in the host response to Salmonella infection in Ank1 mutants.


Assuntos
Anemia Hemolítica/genética , Anquirinas/genética , Peptídeos Catiônicos Antimicrobianos/genética , Códon sem Sentido/efeitos dos fármacos , Etilnitrosoureia/toxicidade , Sobrecarga de Ferro/genética , Infecções por Salmonella/genética , Anemia Hemolítica/metabolismo , Anemia Hemolítica/microbiologia , Anemia Hemolítica/mortalidade , Animais , Anquirinas/metabolismo , Peptídeos Catiônicos Antimicrobianos/deficiência , Eritrócitos/metabolismo , Eritrócitos/patologia , Eritropoetina/genética , Eritropoetina/metabolismo , Expressão Gênica , Predisposição Genética para Doença , Fator 15 de Diferenciação de Crescimento/genética , Fator 15 de Diferenciação de Crescimento/metabolismo , Heme Oxigenase-1/genética , Heme Oxigenase-1/metabolismo , Hepcidinas , Heterozigoto , Homozigoto , Ferro/metabolismo , Sobrecarga de Ferro/metabolismo , Sobrecarga de Ferro/microbiologia , Sobrecarga de Ferro/mortalidade , Fígado/metabolismo , Fígado/patologia , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Infecções por Salmonella/metabolismo , Infecções por Salmonella/microbiologia , Infecções por Salmonella/mortalidade , Salmonella typhimurium/fisiologia , Análise de Sobrevida
14.
Mamm Genome ; 19(5): 309-17, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18560940

RESUMO

The perpetual evolution of drug-resistant microbes, the overwhelming burden of acquired immune suppression due to HIV, the emergence or re-emergence of various pathogens (West Nile virus, pandemic influenza, Creutzfeld-Jacob disease), and increased fears of bioterrorism has drawn a great deal of new attention to infectious diseases. The pathogenesis of infection is characterized by complex interactions of potentially virulent microorganisms with host genetic and acquired factors. Chemical mutagenesis of the mouse genome provides a robust method to unravel this challenging problem. To deepen our understanding of the natural host response to pathogens, our team and others are interrogating the mouse genome to define genes that are crucial to the defense against infectious diseases (pathogen recognition, viral defense, bacterial defense, prion infection). In this review we highlight the current progress of these efforts and propose a toolbox for other groups that are interested in this endeavor.


Assuntos
Doenças Transmissíveis Emergentes/prevenção & controle , Mutagênese/efeitos dos fármacos , Animais , Doenças Transmissíveis Emergentes/diagnóstico , Doenças Transmissíveis Emergentes/genética , Etilnitrosoureia/farmacologia , Programas de Rastreamento , Camundongos , Linhagem
15.
FEBS J ; 275(20): 5074-89, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18786141

RESUMO

The natural resistance-associated macrophage protein 1 (Nramp1), which belongs to a conserved family of membrane metal transporters, contributes to phagocyte-autonomous antimicrobial defense mechanisms. Genetic polymorphisms in the human NRAMP1 gene predispose to susceptibility to infectious or inflammatory diseases. To characterize the transcriptional mechanisms controlling NRAMP1 expression, we previously showed that a 263 bp region upstream of the ATG drives basal promoter activity, and that a 325 bp region further upstream confers myeloid specificity and activation during differentiation of HL-60 cells induced by vitamin D. Herein, the major transcription start site was mapped in the basal region by S1 protection assay, and two cis-acting elements essential for myeloid transactivation were characterized by in vitro DNase footprinting, electrophoretic mobility shift experiments, in vivo transfection assays using linker-mutated constructs, and chromatin immunoprecipitation assays in differentiated monocytic cells. One distal cis element binds Sp1 and is required for NRAMP1 myeloid regulation. Another site in the proximal region binds CCAAT enhancer binding proteins alpha or beta and is crucial for transcription. This study implicates Sp1 and C/EBP factors in regulating the expression of the NRAMP1 gene in myeloid cells.


Assuntos
Proteínas Estimuladoras de Ligação a CCAAT/fisiologia , Proteínas de Transporte de Cátions/genética , Regulação da Expressão Gênica , Fator de Transcrição Sp1/fisiologia , Sítios de Ligação , Linhagem Celular , Elementos Facilitadores Genéticos , Humanos , Células Mieloides , Sítio de Iniciação de Transcrição , Transcrição Gênica
16.
J Mol Evol ; 57(4): 363-76, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-14708570

RESUMO

Eukaryotic Nramp genes encode divalent metal ion permeases important for nutrition and resistance to microbial infection. Bacterial homologs encode proton-dependent transporters of manganese (MntH), and other divalent metal ions. Bacterial MntH were classified in three homology groups (A, B, C) and MntH C further subdivided in Calpha, Cbeta, Cgamma. The proteins from C. tepidum (MntH B) and E. faecalis (MntH Cbeta1, 2), divergent in sequence and hydropathy profile, conferred increased metal sensitivity when expressed in E. coli, suggesting conservation of divalent metal transport function in MntH B and C. Several genomic evidence suggest horizontal gene transfer (HGT) of mntH C genes: (i) The enterobacteria Wigglesworthia mntH Cbeta gene is linked to an Asn t-RNA, and its sequence most conserved with Gram positive bacteria homologs; (ii) all the Cbeta genes identified in oral streptococcaceae are associated with different potentially mobile DNA elements; (iii) Lactococcus lactis and Burkholderia mallei genomes contain an mntH gene prematurely terminated and a novel full-length mntH C gene; (iv) remarkable sequence relatedness between the unicellular alga C. reinhardtii "prototype" Nramp and some MntH Calpha (e.g., Nostoc spp., Listeria spp.) suggests HGT between Eukarya and Bacteria. Other "prototype" Nramp genes (intronless, encoding proteins strongly conserved with MntH A and B proteins) identified in invertebrates represent a possible source for transfer of Nramp genes toward opportunistic bacteria. This study demonstrates complex evolution of MntH in Bacteria. It is proposed that "prototype" Nramp are ancestors of bacterial MntH C proteins, which could facilitate bacterial infection.


Assuntos
Bactérias/genética , Proteínas de Bactérias , Proteínas de Transporte de Cátions/genética , Proteínas de Escherichia coli , Transferência Genética Horizontal/genética , Genes Bacterianos/genética , Transporte Biológico , Proteínas de Transporte/classificação , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Elementos de DNA Transponíveis/genética , Escherichia coli/genética , Células Eucarióticas/metabolismo , Ligação Genética/genética , Metais/metabolismo , Fases de Leitura Aberta/genética , Filogenia , Streptococcaceae/genética , Wigglesworthia/genética
17.
Blood ; 100(1): 268-75, 2002 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-12070036

RESUMO

Mutations at the Nramp1 gene cause susceptibility to infections with intracellular pathogens. In human blood, polymorphonuclear (PMN) leukocytes are the most abundant site of NRAMP1 messenger RNA (mRNA) expression, suggesting that NRAMP1 plays an important role in the activity of these cells. By Northern blot analysis, NRAMP1 mRNA was only detected in most mature neutrophils from bone marrow (band and segmented cells). A high-affinity polyclonal rabbit antihuman NRAMP1 antibody directed against the amino terminus of the protein was produced and used to study cellular and subcellular localization of the protein in primary human neutrophils. Subcellular fractionation of granule populations together with immunoblotting studies with granule-specific markers indicate that NRAMP1 expression is primarily in tertiary granules. These granules are positive for the matrix enzyme gelatinase and the membrane subunit of the vacuolar H(+)/ATPase and can be recruited for exocytosis by treatment of neutrophils with phorbol myristate acetate. Immunogold studies by cryoelectron microscopy with primary neutrophils confirm that a majority (75%) of NRAMP1-positive granules are also positive for gelatinase, but they also suggest further heterogeneity in this granule population. Presence of NRAMP1 in tertiary granules is in agreement with the late-stage appearance of NRAMP1 mRNA during neutrophil maturation in bone marrow. Finally, immunofluorescence studies of Candida albicans-containing phagosomes formed in neutrophils indicate that NRAMP1 is recruited from tertiary granules to the phagosomal membrane on phagocytosis, supporting a role for NRAMP1 in the antimicrobial defenses of human neutrophils.


Assuntos
Proteínas de Transporte de Cátions/metabolismo , Grânulos Citoplasmáticos/metabolismo , Neutrófilos/ultraestrutura , Animais , Anticorpos/isolamento & purificação , Proteínas de Transporte de Cátions/genética , Compartimento Celular , Humanos , Immunoblotting , Neutrófilos/metabolismo , Fagossomos/metabolismo , RNA Mensageiro/metabolismo , Coelhos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA