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1.
Am J Respir Cell Mol Biol ; 50(5): 995-1004, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24328793

RESUMO

Pneumococcal pneumonia is a leading cause of bacterial infection and death worldwide. Current diagnostic tests for detecting Streptococcus pneumoniae can be unreliable and can mislead clinical decision-making and treatment. To address this concern, we developed a preclinical model of pneumococcal pneumonia in nonhuman primates useful for identifying novel biomarkers, diagnostic tests, and therapies for human S. pneumoniae infection. Adult colony-bred baboons (n = 15) were infected with escalating doses of S. pneumoniae (Serotype 19A-7). We characterized the pathophysiological and serological profiles of healthy and infected animals over 7 days. Pneumonia was prospectively defined by the presence of three criteria: (1) change in white blood cell count, (2) isolation of S. pneumoniae from bronchoalveolar lavage fluid (BALF) or blood, and (3) concurrent signs/symptoms of infection. Animals given 10(9) CFU consistently met our definition and developed a phenotype of tachypnea, tachycardia, fever, hypoxemia, and radiographic lobar infiltrates at 48 hours. BALF and plasma cytokines, including granulocyte colony-stimulating factor, IL-6, IL-10, and IL-1ra, peaked at 24 to 48 hours. At necropsy, there was lobar consolidation with frequent pleural involvement. Lung histopathology showed alveolar edema and macrophage influx in areas of organizing pneumonia. Hierarchical clustering of peripheral blood RNA data at 48 hours correctly identified animals with and without pneumonia. Dose-dependent inoculation of baboons with S. pneumoniae produces a host response ranging from spontaneous clearance (10(6) CFU) to severe pneumonia (10(9) CFU). Selected BALF and plasma cytokine levels and RNA profiles were associated with severe pneumonia and may provide clinically useful parameters after validation.


Assuntos
Modelos Animais de Doenças , Pneumonia Pneumocócica/imunologia , Pneumonia Pneumocócica/microbiologia , Primatas/imunologia , Primatas/microbiologia , Animais , Líquido da Lavagem Broncoalveolar/imunologia , Líquido da Lavagem Broncoalveolar/microbiologia , Fator Estimulador de Colônias de Granulócitos/imunologia , Fator Estimulador de Colônias de Granulócitos/metabolismo , Interleucinas/imunologia , Interleucinas/metabolismo , Pulmão/imunologia , Pulmão/metabolismo , Pulmão/microbiologia , Papio/imunologia , Papio/metabolismo , Papio/microbiologia , Pneumonia Pneumocócica/metabolismo , Primatas/metabolismo , Streptococcus pneumoniae/imunologia
2.
Eukaryot Cell ; 12(11): 1439-50, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23975889

RESUMO

Cryptococcus neoformans and C. gattii cause meningoencephalitis and are an increasing human health threat. These pathogenic Cryptococcus species are neurotropic and persist in the cerebrospinal fluid (CSF) of the mammalian host during infection. In order to survive in the host, pathogenic fungi must procure nutrients, such as carbon and nitrogen, from the CSF. To enhance our understanding of nutrient acquisition during central nervous system infection by Cryptococcus species, we examined the utilization of nitrogen sources available in CSF. We screened for the growth and capsule production of 817 global environmental and clinical isolates on various sources of nitrogen. Both environmental and clinical strains grew robustly on uric acid, Casamino Acids, creatinine, and asparagine as sole nitrogen sources. Urea induced the greatest magnitude of capsule induction. This induction was greater in Cryptococcus gattii than in C. neoformans. We confirmed the ability of nonpreferred nitrogen sources to increase capsule production in pathogenic species of Cryptococcus. Since urea is metabolized to ammonia and CO(2) (a known signal for capsule induction), we examined urea metabolism mutants for their transcriptional response to urea regarding capsule production. The transcriptional profile of C. neoformans under urea-supplemented conditions revealed both similar and unique responses to other capsule-inducing conditions, including both intra- and extracellular urea utilization. As one of the most abundant nitrogen sources in the CSF, the ability of Cryptococcus to import urea and induce capsule production may substantially aid this yeast's survival and propagation in the host.


Assuntos
Cryptococcus/metabolismo , Cápsulas Fúngicas/metabolismo , Nitrogênio/metabolismo , Aminoácidos/metabolismo , Asparagina/metabolismo , Creatinina/metabolismo , Cryptococcus/citologia , Cryptococcus/genética , Mutação , Ureia/metabolismo , Ácido Úrico/metabolismo
3.
PLoS Pathog ; 6(8): e1001069, 2010 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-20865172

RESUMO

Fungal pathogens exploit diverse mechanisms to survive exposure to antifungal drugs. This poses concern given the limited number of clinically useful antifungals and the growing population of immunocompromised individuals vulnerable to life-threatening fungal infection. To identify molecules that abrogate resistance to the most widely deployed class of antifungals, the azoles, we conducted a screen of 1,280 pharmacologically active compounds. Three out of seven hits that abolished azole resistance of a resistant mutant of the model yeast Saccharomyces cerevisiae and a clinical isolate of the leading human fungal pathogen Candida albicans were inhibitors of protein kinase C (PKC), which regulates cell wall integrity during growth, morphogenesis, and response to cell wall stress. Pharmacological or genetic impairment of Pkc1 conferred hypersensitivity to multiple drugs that target synthesis of the key cell membrane sterol ergosterol, including azoles, allylamines, and morpholines. Pkc1 enabled survival of cell membrane stress at least in part via the mitogen activated protein kinase (MAPK) cascade in both species, though through distinct downstream effectors. Strikingly, inhibition of Pkc1 phenocopied inhibition of the molecular chaperone Hsp90 or its client protein calcineurin. PKC signaling was required for calcineurin activation in response to drug exposure in S. cerevisiae. In contrast, Pkc1 and calcineurin independently regulate drug resistance via a common target in C. albicans. We identified an additional level of regulatory control in the C. albicans circuitry linking PKC signaling, Hsp90, and calcineurin as genetic reduction of Hsp90 led to depletion of the terminal MAPK, Mkc1. Deletion of C. albicans PKC1 rendered fungistatic ergosterol biosynthesis inhibitors fungicidal and attenuated virulence in a murine model of systemic candidiasis. This work establishes a new role for PKC signaling in drug resistance, novel circuitry through which Hsp90 regulates drug resistance, and that targeting stress response signaling provides a promising strategy for treating life-threatening fungal infections.


Assuntos
Calcineurina/genética , Farmacorresistência Fúngica/genética , Proteínas Fúngicas/genética , Proteínas de Choque Térmico HSP90/genética , Proteínas Quinases Ativadas por Mitógeno/genética , Proteína Quinase C/metabolismo , Animais , Antifúngicos/farmacologia , Calcineurina/metabolismo , Candida albicans/genética , Candida albicans/metabolismo , Proteínas Fúngicas/metabolismo , Proteínas de Choque Térmico HSP90/metabolismo , Immunoblotting , Camundongos , Testes de Sensibilidade Microbiana , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Transdução de Sinais/fisiologia
4.
J Biol Chem ; 285(3): 1957-66, 2010 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-19903816

RESUMO

Synaptic transmission depends on neurotransmitter pools stored within vesicles that undergo regulated exocytosis. In the brain, the vesicular monoamine transporter-2 (VMAT(2)) is responsible for the loading of dopamine (DA) and other monoamines into synaptic vesicles. Prior to storage within vesicles, DA synthesis occurs at the synaptic terminal in a two-step enzymatic process. First, the rate-limiting enzyme tyrosine hydroxylase (TH) converts tyrosine to di-OH-phenylalanine. Aromatic amino acid decarboxylase (AADC) then converts di-OH-phenylalanine into DA. Here, we provide evidence that VMAT(2) physically and functionally interacts with the enzymes responsible for DA synthesis. In rat striata, TH and AADC co-immunoprecipitate with VMAT(2), whereas in PC 12 cells, TH co-immunoprecipitates with the closely related VMAT(1) and with overexpressed VMAT(2). GST pull-down assays further identified three cytosolic domains of VMAT(2) involved in the interaction with TH and AADC. Furthermore, in vitro binding assays demonstrated that TH directly interacts with VMAT(2). Additionally, using fractionation and immunoisolation approaches, we demonstrate that TH and AADC associate with VMAT(2)-containing synaptic vesicles from rat brain. These vesicles exhibited specific TH activity. Finally, the coupling between synthesis and transport of DA into vesicles was impaired in the presence of fragments involved in the VMAT(2)/TH/AADC interaction. Taken together, our results indicate that DA synthesis can occur at the synaptic vesicle membrane, where it is physically and functionally coupled to VMAT(2)-mediated transport into vesicles.


Assuntos
Dopamina/biossíntese , Dopamina/metabolismo , Vesículas Sinápticas/metabolismo , Animais , Descarboxilases de Aminoácido-L-Aromático/imunologia , Descarboxilases de Aminoácido-L-Aromático/metabolismo , Transporte Biológico , Encéfalo/citologia , Encéfalo/enzimologia , Citosol/enzimologia , Citosol/metabolismo , Humanos , Imunoprecipitação , Masculino , Células PC12 , Estrutura Terciária de Proteína , Ratos , Vesículas Sinápticas/enzimologia , Tirosina 3-Mono-Oxigenase/imunologia , Tirosina 3-Mono-Oxigenase/metabolismo , Proteínas Vesiculares de Transporte de Monoamina/química , Proteínas Vesiculares de Transporte de Monoamina/metabolismo
5.
J Neurosci ; 29(14): 4592-604, 2009 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-19357284

RESUMO

Uptake through the dopamine transporter (DAT) represents the primary mechanism used to terminate dopaminergic transmission in brain. Although it is well known that dopamine (DA) taken up by the transporter is used to replenish synaptic vesicle stores for subsequent release, the molecular details of this mechanism are not completely understood. Here, we identified the synaptic vesicle protein synaptogyrin-3 as a DAT interacting protein using the split ubiquitin system. This interaction was confirmed through coimmunoprecipitation experiments using heterologous cell lines and mouse brain. DAT and synaptogyrin-3 colocalized at presynaptic terminals from mouse striatum. Using fluorescence resonance energy transfer microscopy, we show that both proteins interact in live neurons. Pull-down assays with GST (glutathione S-transferase) proteins revealed that the cytoplasmic N termini of both DAT and synaptogyrin-3 are sufficient for this interaction. Furthermore, the N terminus of DAT is capable of binding purified synaptic vesicles from brain tissue. Functional assays revealed that synaptogyrin-3 expression correlated with DAT activity in PC12 and MN9D cells, but not in the non-neuronal HEK-293 cells. These changes were not attributed to changes in transporter cell surface levels or to direct effect of the protein-protein interaction. Instead, the synaptogyrin-3 effect on DAT activity was abolished in the presence of the vesicular monoamine transporter-2 (VMAT2) inhibitor reserpine, suggesting a dependence on the vesicular DA storage system. Finally, we provide evidence for a biochemical complex involving DAT, synaptogyrin-3, and VMAT2. Collectively, our data identify a novel interaction between DAT and synaptogyrin-3 and suggest a physical and functional link between DAT and the vesicular DA system.


Assuntos
Proteínas da Membrana Plasmática de Transporte de Dopamina/fisiologia , Proteínas de Membrana/fisiologia , Proteínas do Tecido Nervoso/fisiologia , Vesículas Sinápticas/fisiologia , Animais , Proteínas da Membrana Plasmática de Transporte de Dopamina/genética , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Humanos , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Células PC12 , Ratos , Vesículas Sinápticas/genética , Vesículas Sinápticas/metabolismo , Sinaptogirinas , Transfecção
6.
J Neurochem ; 110(2): 581-94, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19457116

RESUMO

Synaptic transmission depends on the efficient loading of transmitters into synaptic vesicles by vesicular neurotransmitter transporters. The vesicular monoamine transporter-2 (VMAT2) is essential for loading monoamines into vesicles and maintaining normal neurotransmission. In an effort to understand the regulatory mechanisms associated with VMAT2, we have embarked upon a systematic search for interacting proteins. Glutathione-S-transferase pull-down assays combined with mass spectrometry led to the identification of the 70-kDa heat shock cognate protein (Hsc70) as a VMAT2 interacting protein. Co-immunoprecipitation experiments in brain tissue and heterologous cells confirmed this interaction. A direct binding was observed between the amino terminus and the third cytoplasmic loop of VMAT2, as well as, a region containing the substrate binding and the carboxy-terminal domains of Hsc70. Furthermore, VMAT2 and Hsc70 co-fractionated with purified synaptic vesicles obtained from a sucrose gradient, suggesting that this interaction occurs at the synaptic vesicle membrane. The functional significance of this novel VMAT2/Hsc70 interaction was examined by performing vesicular uptake assays in heterologous cells and purified synaptic vesicles from brain tissue. Recombinant Hsc70 produced a dose-dependent inhibition of VMAT2 activity. This effect was mimicked by the closely related Hsp70 protein. In contrast, VMAT2 activity was not altered in the presence of previously denatured Hsc70 or Hsp70, as well as the unrelated Hsp60 protein; confirming the specificity of the Hsc70 effect. Finally, a purified Hsc70 fragment that binds VMAT2 was sufficient to inhibit VMAT2 activity in synaptic vesicles. Our results suggest an important role for Hsc70 in VMAT2 function and regulation.


Assuntos
Proteínas de Choque Térmico HSC70/metabolismo , Chaperonas Moleculares/metabolismo , Proteínas Vesiculares de Transporte de Monoamina/metabolismo , Sequência de Aminoácidos , Animais , Células CHO , Cricetinae , Cricetulus , Proteínas de Choque Térmico HSC70/fisiologia , Humanos , Masculino , Chaperonas Moleculares/fisiologia , Dados de Sequência Molecular , Fragmentos de Peptídeos/metabolismo , Fragmentos de Peptídeos/fisiologia , Ratos , Ratos Sprague-Dawley , Proteínas Vesiculares de Transporte de Monoamina/antagonistas & inibidores
7.
Mol Pharmacol ; 74(6): 1521-32, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18768736

RESUMO

Rxt1/NTT4 (SLC6A17) belongs to a gene family of "orphan transporters" whose substrates and consequently functions remain unidentified. Although Rxt1/NTT4 was previously thought to function as a sodium-dependent plasma membrane transporter, recent studies localized the protein to synaptic vesicles of glutamatergic and GABAergic neurons. Here, we provide evidence indicating that Rxt1/NTT4 functions as a vesicular transporter selective for proline, glycine, leucine, and alanine. Using Western blot, immunoprecipitation, immunocytochemistry, and polymerase chain reaction approaches, we demonstrate that PC12 cells express the Rxt1/NTT4 gene and protein. Small interfering RNA (siRNA)-mediated knockdown of Rxt1/NTT4 in PC12 cells resulted in selective reductions in uptake levels for proline, glycine, leucine, and alanine. Likewise, gas chromatography analysis of amino acid content in an enriched synaptic vesicle fraction from wild-type and siRNA-Rxt1/NTT4 PC12 cells revealed that proline, glycine, leucine, and alanine levels were decreased in siRNA-treated cells compared with wild-type cells. Furthermore, Rxt1/NTT4-transfected Chinese hamster ovary (CHO) cells exhibited significant uptake increases of these amino acids compared with mock-transfected CHO cells. Finally, proline uptake in both PC12 cells and Rxt1/NTT4-transfected CHO cells was dependent on the electrochemical gradient maintained by the vacuolar-type H(+)-ATPase. These data indicate that the orphan Rxt1/NTT4 protein functions as a vesicular transporter for proline, glycine, leucine, and alanine, further suggesting its important role in synaptic transmission.


Assuntos
Sistemas de Transporte de Aminoácidos/metabolismo , Aminoácidos/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Vesículas Sinápticas/metabolismo , Alanina/metabolismo , Animais , Células CHO , Cricetinae , Cricetulus , Glicina/metabolismo , Humanos , Técnicas In Vitro , Leucina/metabolismo , Proteínas de Membrana Transportadoras/genética , Camundongos , Proteínas do Tecido Nervoso/genética , Células PC12 , Prolina/metabolismo , RNA Interferente Pequeno/genética , Ratos
8.
Curr Biol ; 14(14): 1222-31, 2004 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-15268851

RESUMO

BACKGROUND: The c-Abl and Arg proteins comprise a unique family of nonreceptor tyrosine kinases that have been implicated in the regulation of cell proliferation and survival, cytoskeletal reorganization, cell migration, and the response to oxidative stress and DNA damage. Targeted deletion or mutation of c-Abl in mice results in a variety of immune system phenotypes, including splenic and thymic atrophy, lymphopenia, and an increased susceptibility to infection. However, despite the generation of these mice over a decade ago, little is known regarding the mechanisms responsible for these phenotypes or the immune-related consequences of ablation of both the c-Abl and Arg kinases, which are coexpressed in lymphoid tissues. RESULTS: Here, we report that T cell receptor (TCR) stimulation results in activation of the endogenous Abl kinases. We demonstrate that Zap70 and the transmembrane adaptor linker for activation of T cells (LAT) are targets of the Abl kinases, and that loss of Abl kinase activity reduces TCR-induced Zap70 phosphorylation at tyrosine 319. This correlates with diminished LAT tyrosine phosphorylation, as well as reduced tyrosine phosphorylation and recruitment of phospholipase Cgamma1 to LAT. Significantly, we show that Abl kinase activity is required for maximal signaling leading to transcription of the IL-2 promoter, as well as TCR-induced IL-2 production and proliferation of primary T cells. CONCLUSIONS: We conclude that the Abl kinases have a role in the regulation of TCR-mediated signal transduction leading to IL-2 production and cell proliferation.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Regulação da Expressão Gênica , Ativação Linfocitária/fisiologia , Proteínas Tirosina Quinases/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Transdução de Sinais/fisiologia , Animais , Benzamidas , Western Blotting , Proteínas de Transporte/metabolismo , Células Cultivadas , Ativação Enzimática , Mesilato de Imatinib , Interleucina-2/metabolismo , Luciferases , Proteínas de Membrana/metabolismo , Camundongos , Mutagênese Sítio-Dirigida , Oligonucleotídeos , Fosfoproteínas/metabolismo , Fosforilação , Piperazinas/metabolismo , Plasmídeos/genética , Testes de Precipitina , Estrutura Terciária de Proteína , Pirimidinas/metabolismo , Proteína-Tirosina Quinase ZAP-70
9.
Mol Cell Biol ; 24(24): 10905-22, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15572692

RESUMO

The Abl-interactor (Abi) family of adaptor proteins has been linked to signaling pathways involving the Abl tyrosine kinases and the Rac GTPase. Abi proteins localize to sites of actin polymerization in protrusive membrane structures and regulate actin dynamics in vitro. Here we demonstrate that Abi2 modulates cell morphogenesis and migration in vivo. Homozygous deletion of murine abi2 produced abnormal phenotypes in the eye and brain, the tissues with the highest Abi2 expression. In the absence of Abi2, secondary lens fiber orientation and migration were defective in the eye, without detectable defects in proliferation, differentiation, or apoptosis. These phenotypes were consistent with the localization of Abi2 at adherens junctions in the developing lens and at nascent epithelial cell adherens junctions in vitro. Downregulation of Abi expression by RNA interference impaired adherens junction formation and correlated with downregulation of the Wave actin-nucleation promoting factor. Loss of Abi2 also resulted in cell migration defects in the neocortex and hippocampus, abnormal dendritic spine morphology and density, and severe deficits in short- and long-term memory. These findings support a role for Abi2 in the regulation of cytoskeletal dynamics at adherens junctions and dendritic spines, which is critical for intercellular connectivity, cell morphogenesis, and cognitive functions.


Assuntos
Movimento Celular/genética , Espinhas Dendríticas/genética , Proteínas de Homeodomínio/genética , Aprendizagem , Memória , Morfogênese/genética , Proteínas Adaptadoras de Transdução de Sinal , Junções Aderentes/metabolismo , Animais , Linhagem Celular , Dendritos/genética , Cães , Embrião de Mamíferos/citologia , Fibroblastos/metabolismo , Deleção de Genes , Células HeLa , Hipocampo/citologia , Proteínas de Homeodomínio/metabolismo , Homozigoto , Humanos , Cristalino/embriologia , Cristalino/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neocórtex/citologia , Interferência de RNA , RNA Interferente Pequeno/metabolismo
10.
Leuk Res ; 28(3): 285-94, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-14687624

RESUMO

p185 Bcr-Abl has a more aggressive biological/clinical leukemia phenotype than p210 Bcr-Abl. In this study, we examined differential gene expression using microarrays to determine if upregulation or downregulation of specific genes may explain the distinct phenotypes produced by the two Bcr-Abl forms. RNA was collected from mouse bone marrow mononuclear cells expressing equivalent levels of p185 or p210, and the RNAs were subjected to microarray analysis. Significant differences in gene expression were observed on hierarchical clustering. A group of interferon-gamma-inducible genes, including those encoding a family of 47 kDa GTPases, were significantly increased in p185 versus p210. This family of GTPases has previously been implicated in interferon-gamma-induced resistance against intracellular pathogens, however their exact cellular functions are unknown. Our data suggest that their increased expression may contribute to the biological/clinical phenotype associated with p185.


Assuntos
Proteínas de Fusão bcr-abl/fisiologia , Regulação Leucêmica da Expressão Gênica , Interferon gama/fisiologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Proteínas de Neoplasias/biossíntese , Animais , Células da Medula Óssea/metabolismo , Células da Medula Óssea/patologia , Citocinas/farmacologia , Proteínas de Fusão bcr-abl/biossíntese , Proteínas de Fusão bcr-abl/genética , GTP Fosfo-Hidrolases/biossíntese , GTP Fosfo-Hidrolases/genética , Perfilação da Expressão Gênica , Regulação Leucêmica da Expressão Gênica/efeitos dos fármacos , Regulação Leucêmica da Expressão Gênica/fisiologia , Humanos , Interferon gama/análise , Leucemia Mielogênica Crônica BCR-ABL Positiva/enzimologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Camundongos , Peso Molecular , Proteínas de Neoplasias/genética , Análise de Sequência com Séries de Oligonucleotídeos , Fenótipo , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/genética , Isoformas de Proteínas/fisiologia , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/fisiologia , Proteínas Recombinantes/farmacologia , Transcrição Gênica , Transfecção
11.
J Am Heart Assoc ; 3(3): e000670, 2014 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-24922625

RESUMO

BACKGROUND: Left ventricular heart failure (LVHF) remains progressive and fatal and is a formidable health problem because ever-larger numbers of people are diagnosed with this disease. Therapeutics, while relieving symptoms and extending life in some cases, cannot resolve this process and transplant remains the option of last resort for many. Our team has described a widely expressed cell surface receptor (CD47) that is activated by its high-affinity secreted ligand, thrombospondin 1 (TSP1), in acute injury and chronic disease; however, a role for activated CD47 in LVHF has not previously been proposed. METHODS AND RESULTS: In experimental LVHF TSP1-CD47 signaling is increased concurrent with up-regulation of cardiac histone deacetylase 3 (HDAC3). Mice mutated to lack CD47 displayed protection from transverse aortic constriction (TAC)-driven LVHF with enhanced cardiac function, decreased cellular hypertrophy and fibrosis, decreased maladaptive autophagy, and decreased expression of HDAC3. In cell culture, treatment of cardiac myocyte CD47 with a TSP1-derived peptide, which binds and activates CD47, increased HDAC3 expression and myocyte hypertrophy in a Ca(2+)/calmodulin protein kinase II (CaMKII)-dependent manner. Conversely, antibody blocking of CD47 activation, or pharmacologic inhibition of CaMKII, suppressed HDAC3 expression, decreased myocyte hypertrophy, and mitigated established LVHF. Downstream gene suppression of HDAC3 mimicked the protective effects of CD47 blockade and decreased hypertrophy in myocytes and mitigated LVHF in animals. CONCLUSIONS: These data identify a proximate role for the TSP1-CD47 axis in promoting LVHF by CaKMII-mediated up-regulation of HDAC3 and suggest novel therapeutic opportunities.


Assuntos
Antígeno CD47/fisiologia , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/fisiologia , Insuficiência Cardíaca/fisiopatologia , Histona Desacetilases/biossíntese , Animais , Células Cultivadas , Indução Enzimática/fisiologia , Insuficiência Cardíaca/etiologia , Histona Desacetilases/fisiologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Miócitos Cardíacos/fisiologia , Ratos Sprague-Dawley , Transdução de Sinais/fisiologia
12.
PLoS One ; 7(9): e44734, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22970302

RESUMO

The molecular chaperone Hsp90 orchestrates regulatory circuitry governing fungal morphogenesis, biofilm development, drug resistance, and virulence. Hsp90 functions in concert with co-chaperones to regulate stability and activation of client proteins, many of which are signal transducers. Here, we characterize the first Hsp90 co-chaperone in the leading human fungal pathogen, Candida albicans. We demonstrate that Sgt1 physically interacts with Hsp90, and that it governs C. albicans morphogenesis and drug resistance. Genetic depletion of Sgt1 phenocopies depletion of Hsp90, inducing yeast to filament morphogenesis and invasive growth. Sgt1 governs these traits by bridging two morphogenetic regulators: Hsp90 and the adenylyl cyclase of the cAMP-PKA signaling cascade, Cyr1. Sgt1 physically interacts with Cyr1, and depletion of either Sgt1 or Hsp90 activates cAMP-PKA signaling, revealing the elusive link between Hsp90 and the PKA signaling cascade. Sgt1 also mediates tolerance and resistance to the two most widely deployed classes of antifungal drugs, azoles and echinocandins. Depletion of Sgt1 abrogates basal tolerance and acquired resistance to azoles, which target the cell membrane. Depletion of Sgt1 also abrogates tolerance and resistance to echinocandins, which target the cell wall, and renders echinocandins fungicidal. Though Sgt1 and Hsp90 have a conserved impact on drug resistance, the underlying mechanisms are distinct. Depletion of Hsp90 destabilizes the client protein calcineurin, thereby blocking crucial responses to drug-induced stress; in contrast, depletion of Sgt1 does not destabilize calcineurin, but blocks calcineurin activation in response to drug-induced stress. Sgt1 influences not only morphogenesis and drug resistance, but also virulence, as genetic depletion of C. albicans Sgt1 leads to reduced kidney fungal burden in a murine model of systemic infection. Thus, our characterization of the first Hsp90 co-chaperone in a fungal pathogen establishes C. albicans Sgt1 as a global regulator of morphogenesis and drug resistance, providing a new target for treatment of life-threatening fungal infections.


Assuntos
Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Proteínas de Choque Térmico HSP90/metabolismo , Adenilil Ciclases/metabolismo , Antifúngicos/farmacologia , Azóis/farmacologia , Candida albicans/genética , AMP Cíclico/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Farmacorresistência Fúngica , Morfogênese , Ligação Proteica , Transdução de Sinais
13.
PLoS One ; 7(6): e38326, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22719877

RESUMO

Ubiquitination is a reversible protein modification that influences various cellular processes in eukaryotic cells. Deubiquitinating enzymes remove ubiquitin, maintain ubiquitin homeostasis and regulate protein degradation via the ubiquitination pathway. Cryptococcus neoformans is an important basidiomycete pathogen that causes life-threatening meningoencephalitis primarily in the immunocompromised population. In order to understand the possible influence deubiquitinases have on growth and virulence of the model pathogenic yeast Cryptococcus neoformans, we generated deletion mutants of seven putative deubiquitinase genes. Compared to other deubiquitinating enzyme mutants, a ubp5Δ mutant exhibited severely attenuated virulence and many distinct phenotypes, including decreased capsule formation, hypomelanization, defective sporulation, and elevated sensitivity to several external stressors (such as high temperature, oxidative and nitrosative stresses, high salts, and antifungal agents). Ubp5 is likely the major deubiquitinating enzyme for stress responses in C. neoformans, which further delineates the evolutionary divergence of Cryptococcus from the model yeast S. cerevisiae, and provides an important paradigm for understanding the potential role of deubiquitination in virulence by other pathogenic fungi. Other putative deubiquitinase mutants (doa4Δ and ubp13Δ) share some phenotypes with the ubp5Δ mutant, illustrating functional overlap among deubiquitinating enzymes in C. neoformans. Therefore, deubiquitinating enzymes (especially Ubp5) are essential for the virulence composite of C. neoformans and provide an additional yeast survival and propagation advantage in the host.


Assuntos
Cryptococcus neoformans/crescimento & desenvolvimento , Cryptococcus neoformans/patogenicidade , Endopeptidases/metabolismo , Animais , Southern Blotting , Cryptococcus neoformans/enzimologia , Cryptococcus neoformans/fisiologia , Endopeptidases/genética , Endopeptidases/fisiologia , Deleção de Genes , Macrófagos/microbiologia , Camundongos , Reação em Cadeia da Polimerase em Tempo Real , Reprodução , Transcriptoma , Proteases Específicas de Ubiquitina , Urease/biossíntese , Virulência
14.
PLoS One ; 7(9): e45083, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23028773

RESUMO

BACKGROUND: A mouse brain transmigration assessment (MBTA) was created to investigate the central nervous system (CNS) pathogenesis of cryptococcal meningoencephalitis. METHODOLOGY/PRINCIPAL FINDINGS: Two cryptococcal mutants were identified from a pool of 109 pre-selected mutants that were signature-tagged with the nourseothricin acetyltransferase (NAT) resistance cassette. These two mutants displayed abnormal transmigration into the central nervous system. One mutant displaying decreased transmigration contains a null mutation in the putative FNX1 gene, whereas the other mutant possessing a null mutation in the putative RUB1 gene exhibited increased transmigration into the brain. Two macrophage adhesion-defective mutants in the pool, 12F1 and 3C9, showed reduced phagocytosis by macrophages, but displayed no defects in CNS entry suggesting that transit within macrophages (the "Trojan horse" model of CNS entry) is not the primary mechanism for C. neoformans migration into the CNS in this MBTA. CONCLUSIONS/SIGNIFICANCE: This research design provides a new strategy for genetic impact studies on how Cryptococcus passes through the blood-brain barrier (BBB), and the specific isolated mutants in this assay support a transcellular mechanism of CNS entry.


Assuntos
Sistema Nervoso Central/citologia , Sistema Nervoso Central/microbiologia , Cryptococcus neoformans/genética , Cryptococcus neoformans/fisiologia , Genes Fúngicos/genética , Migração Transendotelial e Transepitelial/genética , Acetiltransferases/metabolismo , Animais , Barreira Hematoencefálica/microbiologia , Adesão Celular , Cryptococcus neoformans/crescimento & desenvolvimento , Células Endoteliais/citologia , Células Endoteliais/microbiologia , Estudos de Associação Genética , Testes Genéticos , Camundongos , Microvasos/citologia , Modelos Biológicos , Mutação/genética , Reação em Cadeia da Polimerase , Reprodutibilidade dos Testes , Temperatura , Transcitose
15.
mBio ; 2(3): e00103-11, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21652778

RESUMO

Cryptococcus neoformans is an important fungal pathogen of immunocompromised individuals, with a close relative, Cryptococcus gattii, emerging as a serious threat for the immunocompetent. During initial infection, C. neoformans colonizes the airspaces of the lungs, resulting in pneumonia, and subsequently migrates to the central nervous system (CNS). We sought to understand fungal carbon utilization during colonization of these fundamentally different niches within the host, in particular the roles of gluconeogenesis and glycolysis. We created mutants at key points in the gluconeogenesis/glycolysis metabolic pathways that are restricted for growth on lactate and glucose, respectively. A phosphoenolpyruvate carboxykinase mutant (the pck1Δ mutant), blocked for entry of 2- and 3-carbon substrates into gluconeogenesis and attenuated for virulence in a murine inhalation model, showed wild-type (WT) persistence in a rabbit cerebrospinal fluid (CSF) model of cryptococcosis. Conversely, both the pyruvate kinase (pyk1Δ) and the hexose kinase I and II (hxk1Δ/hxk2Δ) mutants, which show impaired glucose utilization, exhibited severely attenuated virulence in the murine inhalation model of cryptococcosis and decreased persistence in the CNS in both the rabbit CSF and the murine inhalation models while displaying adequate persistence in the lungs of mice. These data suggest that glucose utilization is critical for virulence of C. neoformans and persistence of the yeast in the CNS.


Assuntos
Criptococose/microbiologia , Cryptococcus neoformans/metabolismo , Cryptococcus neoformans/patogenicidade , Glicólise , Animais , Modelos Animais de Doenças , Feminino , Deleção de Genes , Genes Fúngicos , Gluconeogênese , Glucose/metabolismo , Humanos , Ácido Láctico/metabolismo , Masculino , Camundongos , Coelhos , Doenças dos Roedores/microbiologia , Doenças dos Roedores/patologia , Virulência , Fatores de Virulência/genética
16.
Managua; s.n; jun. 2012. iii, [93] p. ilus, tab, graf.
Tese em Espanhol | LILACS | ID: biblio-972254

RESUMO

Desde el punto de vista médico legal, este es el primer estudio de femicidio, realizadoen el Instituto de Medicina Legal de la sede Managua, Nicaragua. Es un estudio de tipodescriptivo; de corte transversal, el cual se realizó, mediante el análisis de losexpedientes médicos legales, como resultados de las autopsias, atendidos en elperíodo comprendido del 01 de enero de 1999 al 30 de junio 2011. El universo loconstituyeron 213 casos de homicidios, siendo la población de estudio representada por159 casos de femicidios, lo cual representó el 74,6% del total del universo.Los resultados concluyeron que la población afectada fueron mujeres en edadreproductiva entre los 18 y 30 años de edad, soltera, “ama de casa” o comerciantes,meseras, obreras, domesticas, habitantes de áreas predominantemente urbanas. En lagran mayoría los agresores de las victimas resultaron ser desconocidos. Así mismo lasarmas de fuego, armas blancas y las manos del agresor fueron los instrumentos másutilizados. Siendo el cuello y la cabeza los sitios anatómicos mayormente afectados,seguidos de tórax. Las tres principales causas de muerte reportadas fueron heridas porarma de fuego, herida por arma blanca y estrangulamiento, es importante mencionarque en este último se encontraron signos de agresión sexual en un 3,2%. Losresultados toxicológicos realizados a las víctimas en la mayoría fueron Negativos ysolamente un 20% del total reportaron ser Positivos. Así mismo las pruebas serológicosy citológicos resultaron positivos en el 14% del total de los casos...


Assuntos
Feminino , Humanos , Violência contra a Mulher , Violência Doméstica , Vítimas de Crime , Dissertações Acadêmicas como Assunto , Teses Eletrônicas
17.
Cochabamba; s.n; dic. 1994. 96 p. graf.
Tese em Espanhol | LIBOCS, LILACS, LIBOE | ID: biblio-1295731

RESUMO

El paro cardio-respiratorio es una situación de urgencia que pone en peligro la vida de los individuos si no se actúa en minutos; el diagnóstico y posibles causas son importantes para seguir con las acciones de primeros auxilios evitando complicaciones con el A B C de la reanimación cardio-respiratoria, la vía de aire permeable, respiración y circulación son fundamentales para mantener la vida del individuo; posteriormente se controlará la eficacia de las acciones valorando los signos de vida. La existencia de material y medicamentos para continuar con la fase II deben ser conocidos y manejados bien para evitar complicaciones o dejar morir a las personas


Assuntos
Humanos , Parada Cardíaca , Tratamento Farmacológico
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