RESUMO
Three polar cyclic hexapeptides differently charged at physiological pH (1â¯=â¯neutral, 2â¯=â¯anionic, 3â¯=â¯cationic) were synthesized and their cell permeability measured. Lipophilicity in octanol/water didn't account for the higher permeability of the cationic derivative but three chromatographic indexes (log KwIAM, log k' HILIC and log k' c-HILIC) were more efficient to this respect. NMR amide chemical shift temperature coefficients (ΔδNH/ΔT) were used to explore the IMHB network of the backbone. MD simulations in different environments (water, chloroform and DMPC lipid bilayer) highlighted that the charged amino group of the lysine moiety of 3 is not involved in the formation of any IMHB in water whereas a different behavior is registered in chloroform and DMPC lipid bilayer. Overall this paper highlights how a combination of experimental and computational approaches could help in comparing permeability and physicochemical properties of neutral and charged cyclic peptides.
Assuntos
Peptídeos Cíclicos/química , 1-Octanol/química , Animais , Cães , Células Madin Darby de Rim Canino , Simulação de Dinâmica Molecular , Ressonância Magnética Nuclear Biomolecular , Peptídeos Cíclicos/administração & dosagem , Permeabilidade , Água/químicaRESUMO
The growing interest for peptide therapeutics calls for new strategies to determine the physico-chemical properties responsible for the interactions of peptides with the environment. This study reports about the lipophilicity of two fragments of the amyloid ß-peptide, Aß 25-35 and Aß 12-28. Firstly, computational studies showed the limits of log D(7.4)oct in describing the lipophilicity of medium-sized peptides. Chromatographic lipophilicity indexes (expressed as log k', the logarithm of the retention factor) were then measured in three different systems to highlight the different skills of Aß 25-35 and Aß 12-28 in giving interactions with polar and apolar environments. CD studies were also performed to validate chromatographic experimental conditions. Results show that Aß 12-28 has a larger skill in promoting hydrophobic and electrostatic interactions than Aß 25-35. This finding proposes a strategy to determine the lipophilicity of peptides for drug discovery purposes but also gives insights in unraveling the debate about the aminoacidic region of Aß responsible for its neurotoxicity.
Assuntos
Peptídeos beta-Amiloides/química , Interações Hidrofóbicas e Hidrofílicas , Fragmentos de Peptídeos/química , Eletricidade Estática , Cromatografia , Dicroísmo Circular , Concentração de Íons de Hidrogênio , Modelos Moleculares , Estrutura Secundária de ProteínaRESUMO
Molecular Interaction Fields (MIFs) based descriptors can be conveniently used to characterize and compare chromatographic scales. In this study, Quantitative Structure-Retention Relationships (QSRR) for eight different chromatographic systems were obtained with VolSurf+ descriptors and Partial Least Squares (PLS). A new and purpose-designed analysis tool highlights the different balance of intermolecular interactions governing solute retention, and estimates the similarity between chromatographic systems.
Assuntos
Cromatografia/métodos , Modelos Químicos , Amitrol (Herbicida)/química , Interações Hidrofóbicas e Hidrofílicas , Análise dos Mínimos Quadrados , Modelos Moleculares , Relação Quantitativa Estrutura-Atividade , TermodinâmicaRESUMO
Accumulating evidences indicate that the cellular and molecular microenvironment of follicular lymphoma (FL) has a key role in both lymphomagenesis and patient outcome. Malignant FL B cells are found admixed to specific stromal and immune cell subsets, in particular CD4(pos) T cells displaying phenotypic features of follicular helper T cells (T(FH)). The goal of our study was to functionally characterize intratumoral CD4(pos) T cells. We showed that CXCR5(hi)ICOS(hi)CD4(pos) T cells sorted from FL biopsies comprise at least two separate cell populations with distinct genetic and functional features: (i) CD25(pos) follicular regulatory T cells (T(FR)), and (ii) CD25(neg) T(FH) displaying a FL-B cell supportive activity without regulatory functions. Furthermore, despite their strong similarities with tonsil-derived T(FH), purified FL-derived T(FH) displayed a specific gene expression profile including an overexpression of several genes potentially involved directly or indirectly in lymphomagenesis, in particular TNF, LTA, IL4 or CD40LG. Interestingly, we further demonstrated that these two last signals efficiently rescued malignant B cells from spontaneous and rituximab-induced apoptosis. Altogether, our study demonstrates that tumor-infiltrating CD4(pos) T cells are more heterogeneous than previously presumed, and underlines for the first time the crucial role of T(FH) in the complex set of cellular interactions within FL microenvironment.
Assuntos
Linfócitos B/patologia , Sobrevivência Celular/imunologia , Linfoma Folicular/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Antígenos CD4/imunologia , Citometria de Fluxo , Perfilação da Expressão Gênica , Humanos , Imuno-Histoquímica , Imunofenotipagem , Subunidade alfa de Receptor de Interleucina-2/imunologia , Linfoma Folicular/genética , Linfoma Folicular/patologia , Receptores CXCR5/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Follicular lymphoma (FL) B cells contract tight connections with their microenvironment, which governs the pathogenesis and progression of the disease. Indeed, specific immune response gene signatures, obtained from whole biopsy samples, have been associated with patient survival. In this study, we performed gene expression profiling of purified B cell and non-B cell compartments obtained from FL and reactive lymph nodes. We identified 677 non-redundant genes defining the FL interface and involving 26 FL-specific functional networks. This approach highlighted an interleukin-4 (IL-4)-centered pathway associated with an activation of signal transducer and activator of transcription 6 (STAT6), which favors overexpression of IL-4-target genes. In addition, FL microenvironment was characterized by a strong enrichment in follicular helper T cells (T(FH)), as demonstrated through transcriptomic and flow cytometry analyses. The majority of phospho-STAT6(pos) B cells were located at the vicinity of cells expressing the programmed death 1 (PD-1) T(FH) marker. Moreover, purified FL-derived T(FH), expressed IL4 at very high levels compared with purified tonsil-derived T(FH) or non-T(FH) microenvironment. Altogether, our study demonstrated that tumor-infiltrating T(FH) specifically express functional IL-4 in FL, creating an IL-4-dependent T(FH)-B cell axis. This cross talk could sustain FL pathogenesis and represent a new potential therapeutic target.
Assuntos
Linfócitos B/fisiologia , Interleucina-4/fisiologia , Linfócitos do Interstício Tumoral/fisiologia , Linfoma Folicular/imunologia , Linfócitos T Auxiliares-Indutores/fisiologia , Comunicação Celular , Separação Celular/métodos , Perfilação da Expressão Gênica , Humanos , Ativação Linfocitária , Linfoma Folicular/etiologia , Análise de Sequência com Séries de Oligonucleotídeos , Fator de Transcrição STAT6/fisiologiaRESUMO
OBJECTIVES: There are differences in symptoms, risk stratification, and efficacy of pharmacological treatments between men and women with coronary artery disease (CAD). The results of clinical studies of cell therapy in CAD patients are mixed. The relevance of sex to response to cell therapy is unknown. We investigated sex-based differences in response to bone marrow mononuclear cells (BM-MNCs) in atherosclerotic apoliproprotein E-knockout (ApoE -/-) mice. METHODS: Twenty-three male and 27 female ApoE -/- mice fed on a high-fat diet received four intravenous BM-MNC injections (C57BL6/J mice) starting at 14 weeks of age; male or female BM-MNCs were administered. Thirteen male and 20 female atherosclerotic ApoE -/- mice received vehicle. Aortic plaque burden (%), recipient bone marrow progenitor cell profiles (FACS-LSR II, FlowJo) and 22 circulating cytokine panel (LINCOplex) were quantified and analyzed statistically (SSPS, P < or 5). RESULTS: Quantitative and semiquantitative results are presented. Increased G-CSF levels correlated with plaque reduction (r = -.86, P = .0004). G-CSF was clustered with IL-15. CONCLUSIONS: Female but not male BM-MNCs exhibited atheroprotection in male atherosclerotic ApoE -/- mice. Plaque lesions did not attenuate atherosclerosis in female ApoE -/- mice with BM-MNCs of either donor sex. An increase in regulatory and in Th2-type response may be required for atheroprotection. Sex-based differences in vascular repair have implications for cell therapy trials in CAD.
Assuntos
Apolipoproteínas E/deficiência , Aterosclerose/prevenção & controle , Citocinas/fisiologia , Leucócitos Mononucleares/transplante , Células Th2/imunologia , Animais , Transplante de Medula Óssea , Feminino , Masculino , Camundongos , Camundongos Knockout , Caracteres SexuaisRESUMO
The role of the professional nurse in the perioperative care of the patient undergoing open heart surgery is beneficial for obtaining a positive outcome for the patient. This article focuses on the preoperative and postoperative nursing care of patients undergoing coronary artery bypass graft surgery. Risk assessment, preoperative preparation, current operative techniques, application of the nursing process immediately after surgery, and common postoperative complications will be explored.
Assuntos
Ponte de Artéria Coronária/enfermagem , Enfermagem Perioperatória/métodos , Ponte de Artéria Coronária/efeitos adversos , Gastroenteropatias/etiologia , Gastroenteropatias/enfermagem , Hemodinâmica , Hemorragia/etiologia , Hemorragia/enfermagem , Humanos , Cuidados Intraoperatórios/métodos , Cuidados Intraoperatórios/enfermagem , Pneumopatias/etiologia , Pneumopatias/enfermagem , Doenças do Sistema Nervoso/etiologia , Doenças do Sistema Nervoso/enfermagem , Dor/etiologia , Dor/enfermagem , Educação de Pacientes como Assunto/métodos , Cuidados Pós-Operatórios/métodos , Cuidados Pós-Operatórios/enfermagem , Cuidados Pré-Operatórios/métodos , Cuidados Pré-Operatórios/enfermagem , Insuficiência Renal/etiologia , Insuficiência Renal/enfermagemRESUMO
Listeria monocytogenes has previously been shown to adapt to a wide variety of environmental niches, principally those associated with low pH, and this compromises its control in food environments. An understanding of the mechanism(s) by which L. monocytogenes survives unfavourable environmental conditions will aid in developing new food processing methods to control the organism in foodstuffs. The present study aimed to gain a further understanding of the physiological basis for the differential effects of one control strategy, namely the use of the lantibiotic nisin. Using propidium iodide (PI) to probe membrane integrity it was shown that L. monocytogenes Scott A was sensitive to nisin (8 ng mL(-)) but this was growth phase dependent with stationary phase cells (OD600=1.2) being much more resistant than exponential phase cells (OD600=0.38). We demonstrate that, using a combination of techniques including fluorescence activated cell sorting (FACS), the membrane adaptations underpinning nisin resistance are triggered much earlier (OD600<0.5) than the onset of stationary phase. The significance of these findings in terms of mechanism and application are discussed.
Assuntos
Antibacterianos/farmacologia , Microbiologia de Alimentos , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/crescimento & desenvolvimento , Nisina/farmacologia , Contagem de Células , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Citometria de Fluxo , Listeria monocytogenes/ultraestrutura , Microscopia Eletrônica de Transmissão , Propídio/químicaRESUMO
AIMS: To investigate the production of bacteriocin-like compounds by Bacillus spp. isolated from the Amazon basin. METHODS AND RESULTS: An antimicrobial substance produced by Bacillus licheniformis strain P40 was inhibitory to a broad range of indicator strains, such as Listeria monocytogenes, Bacillus cereus and clinical isolates of Streptococcus spp. The compound was stable at 100 degrees C, but lost its activity when treated at 121 degrees C/103.5 kPa for 15 min. It was resistant to the proteolytic action of trypsin and papain but sensitive to pronase E and was stable within a wide range of pH (3-11). The substance was bactericidal and bacteriolytic to L. monocytogenes. CONCLUSIONS: An antibacterial peptide produced by Bacillus licheniformis was characterized, presenting a broad spectrum of activity against pathogenic and spoilage organisms. SIGNIFICANCE AND IMPACT OF THE STUDY: The identification of a substance active against important pathogens addresses an important aspect of food safety.
Assuntos
Bacillus/metabolismo , Bacteriocinas/biossíntese , Bacteriocinas/farmacologia , Antibiose , Bacillus cereus/efeitos dos fármacos , Bacteriocinas/química , Bacteriólise , Concentração de Íons de Hidrogênio , Listeria monocytogenes/efeitos dos fármacos , Papaína/metabolismo , Pronase/metabolismo , Streptococcus/efeitos dos fármacos , Temperatura , Tripsina/metabolismoRESUMO
Riparian Management Systems (RiMS) have been proposed to minimize the impacts of agricultural production and improve water quality in Iowa in the Midwestern USA. As part of RiMS, multispecies riparian buffers have been shown to decrease nutrient, pesticide, and sediment concentrations in runoff from adjacent crop fields. However, their effect on nutrients and pesticides moving in groundwater beneath buffers has been discussed only in limited and idealized hydrogeologic settings. Studies in the Bear Creek watershed of central Iowa show the variability inherent in hydrogeologic systems at the watershed scale, some of which may be favorable or unfavorable to future implementation of buffers. Buffers may be optimized by choosing hydrogeologic systems where a shallow groundwater flow system channels water directly through the riparian buffer at velocities that allow for processes such as denitrification to occur.
Assuntos
Conservação dos Recursos Naturais , Agricultura Florestal , Árvores , Poluição da Água/prevenção & controle , Biodegradação Ambiental , Monitoramento Ambiental , Filtração , Fenômenos Geológicos , Geologia , Concentração de Íons de Hidrogênio , Iowa , Nitrogênio/análise , Nitrogênio/metabolismo , Praguicidas/análise , Fósforo/análise , Poluentes do Solo/análise , Água/químicaRESUMO
Hydrogen bonds are major forces of recognition in biochemistry and molecular pharmacology; they are an essential component of intermolecular interactions and determine to a significant extent the 3D-structure of bio-macromolecules. To explore three-dimensional H-bonding properties, a new tool called Molecular Hydrogen-Bonding Potentials (MHBPs) was created. The development of this tool is based on a stepwise procedure similar to the one used successfully to generate the Molecular Lipophilicity Potential (MLP). First, a H-bonding fragmental system was developed starting from published solvatochromic parameters. An atomic H-bonding donor fragmental value (alpha) is associated to each hydrogen atom in a polar moiety. Similarly, an atomic H-bonding acceptor fragmental value (beta) is associated to each polar atom. A distance function and an angle function were defined to take into account variations of the MHBPs in space. The fragmental system and the geometric functions were then combined to generate the MHBPs. These are calculated at each point of an adequate molecular surface or on a three-dimensional grid. The MHBPs were compared with GRID interactions energies and correlated with success to oral drug absorption data. Available examples demonstrate that the MHBPs are a promising computational tool in drug design. Their combination with CoMFA and VolSurf is being studied.
Assuntos
Ligação de Hidrogênio , Algoritmos , Transferência de Energia , Concentração de Íons de Hidrogênio , Computação Matemática , Estrutura Molecular , Software , Relação Estrutura-AtividadeRESUMO
Allergic disorders are characterized by allergen-specific Th2-biased responses. Signals controlling Th2 cell polarization, especially those acting by polarizing dendritic cells (DC) into Th2-promoting DC (DC2), are not well known. Histamine, a mediator released by allergen-stimulated mast cells from allergic subjects, has been reported to activate human immature DC. We have therefore tested whether histamine affects DC polarization. We report here that histamine inhibits LPS-induced IL-12 production and polarizes uncommitted maturing DC into effector DC2. DC matured in the presence of histamine fail to produce IL-12 upon subsequent stimulation and prime Th2 responses, even in presence of IFN-gamma, a potent DC1-driving factor. All these effects are mediated through both H1 and H2 receptors. These data show that histamine is a potent DC2-polarizing factor and provide evidence for a novel mechanism that explains the initiation and maintenance of a predominant Th2 response in allergic disorders.
Assuntos
Células Dendríticas/imunologia , Histamina/farmacologia , Células Th2/imunologia , Diferenciação Celular , Células Cultivadas , Células Dendríticas/efeitos dos fármacos , Humanos , Hipersensibilidade/imunologia , Interferon gama/biossíntese , Interleucina-12/biossíntese , Lipopolissacarídeos/farmacologia , Células Progenitoras Mieloides/efeitos dos fármacos , Células Progenitoras Mieloides/imunologiaRESUMO
PURPOSE: Model compounds containing NO-donor furoxan moieties at the 3-positioned basic lateral chain of 1, a 1,4-dihydropyridine related to nicardipine, were synthesized in order to study their vasodilating activity as well as their basic and lipophilic behaviour. METHODS: All the compounds were obtained by a modified Hantzsch approach. Potentiometry was used to determine pKa and lipophilicity descriptors. The furoxan 4-aryl-1,4-dihydropyridines were assessed for their ability to release nitrite, in the presence of a large excess of cysteine, by the Griess reaction. Vasodilating activity of the products in the absence and in the presence of ODQ, a well-known guanylate cyclase inhibitor, was evaluated on rat thoracic aorta. RESULTS: The compounds display low basicity values and for this reason their log Ds at physiological pH are identical to the log Ps of the neutral forms. Products 2, 3 display vasodilating action principally dependent on their Ca2+-antagonist properties, whereas 4 behaves as a well-balanced hybrid with mixed Ca2+-channel blocker and NO-dependent vasodilator activities. CONCLUSIONS. Nitrogen containing lateral chain at the 3-position of 1 is a suitable molecular region to be modified in order to obtain well-balanced furoxan NO-donor 1,4-DHPs. This manipulation produces a decrease in the basicity. General analysis of pKa and lipophilicity descriptors of these new DHPs suggest that molecular flexibility could influence both their basicity and log PI.
Assuntos
Bloqueadores dos Canais de Cálcio/síntese química , Di-Hidropiridinas/síntese química , Doadores de Óxido Nítrico/síntese química , Animais , Aorta Torácica/efeitos dos fármacos , Aorta Torácica/fisiologia , Bloqueadores dos Canais de Cálcio/química , Bloqueadores dos Canais de Cálcio/farmacologia , Di-Hidropiridinas/química , Di-Hidropiridinas/farmacologia , Relação Dose-Resposta a Droga , Nicardipino/química , Nicardipino/farmacologia , Óxido Nítrico/biossíntese , Doadores de Óxido Nítrico/química , Doadores de Óxido Nítrico/farmacologia , Ratos , Vasodilatação/efeitos dos fármacos , Vasodilatação/fisiologiaRESUMO
PURPOSE: The partitioning of cetirizine in a phosphatidylcholine liposomes/water system was compared with that of hydroxyzine and acrivastine to gain insight into the mechanisms of interaction of its various electrical species with membranes. METHODS: The lipophilicity profiles of the compounds were obtained from equilibrium dialysis and potentiometry, and compared with changes in NMR relaxation rates. RESULTS: The neutral form of hydroxyzine interacted mainly via hydrophobic interactions with the bilayer lipid core of the membrane, whereas for the cationic form both hydrophobic and electrostatic interactions were involved. Zwitterionic and anionic cetirizine were less lipophilic than its cation, which behaved like the corresponding species of hydroxyzine. Zwitterionic cetirizine interacted more by weak electrostatic interactions with the polar headgroups of phospholipids than by hydrophobic interactions with the membrane interior. The lipophilicity of its anion reflected the balance of repulsive electrostatic interactions between the carboxylate and phosphate groups and the hydrophobic interactions with the lipid core. CONCLUSION: The study confirms that various mechanisms influence the interaction of solutes with liposomes. Combining experimental techniques and using suitable reference compounds proves useful.
Assuntos
Cetirizina/química , Antagonistas dos Receptores Histamínicos H1/química , Triprolidina/análogos & derivados , Fenômenos Químicos , Físico-Química , Diálise , Emulsões , Fluoresceínas/química , Hidroxizina/química , Indicadores e Reagentes , Lipossomos/química , Espectroscopia de Ressonância Magnética , Fosfatidilcolinas , Potenciometria , Triprolidina/química , ÁguaRESUMO
Animal and human studies have shown that greatly increasing the amounts of flax seed oil [rich in the (n-3) polyunsaturated fatty acid (PUFA) alpha-linolenic acid (ALNA)] or fish oil [FO; rich in the long chain (n-3) PUFA eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] in the diet can decrease mitogen-stimulated lymphocyte proliferation. The objective of this study was to determine the effect of dietary supplementation with moderate levels of ALNA, gamma-linolenic acid (GLA), arachidonic acid (ARA), DHA or FO on the proliferation of mitogen-stimulated human peripheral blood mononuclear cells (PBMC) and on the production of cytokines by those cells. The study was randomized, placebo-controlled, double-blinded and parallel. Healthy subjects ages 55-75 y consumed nine capsules/d for 12 wk; the capsules contained placebo oil (an 80:20 mix of palm and sunflower seed oils) or blends of placebo oil with oils rich in ALNA, GLA, ARA or DHA or FO. Subjects in these groups consumed 2 g of ALNA or 770 mg of GLA or 680 mg of ARA or 720 mg of DHA or 1 g of EPA plus DHA (720 mg of EPA + 280 mg of DHA) daily from the capsules. Total fat intake from the capsules was 4 g/d. The fatty acid composition of PBMC phospholipids was significantly changed in the GLA, ARA, DHA and FO groups. Lymphocyte proliferation was not significantly affected by the placebo, ALNA, ARA or DHA treatments. GLA and FO caused a significant decrease (up to 65%) in lymphocyte proliferation. This decrease was partly reversed by 4 wk after stopping the supplementation. None of the treatments affected the production of interleukin-2 or interferon-gamma by PBMC and none of the treatments affected the number or proportion of T or B lymphocytes, helper or cytotoxic T lymphocytes or memory helper T lymphocytes in the circulation. We conclude that a moderate level GLA or EPA but not of other (n-6) or (n-3) PUFA can decrease lymphocyte proliferation but not production of interleukin-2 or interferon-gamma.
Assuntos
Óleos de Peixe/administração & dosagem , Ativação Linfocitária/fisiologia , Subpopulações de Linfócitos/efeitos dos fármacos , Ácido gama-Linolênico/administração & dosagem , Idoso , Ácido Araquidônico/administração & dosagem , Ácido Araquidônico/farmacologia , Divisão Celular/efeitos dos fármacos , Suplementos Nutricionais , Ácidos Docosa-Hexaenoicos/administração & dosagem , Ácidos Docosa-Hexaenoicos/farmacologia , Método Duplo-Cego , Feminino , Óleos de Peixe/farmacologia , Humanos , Interferon gama/biossíntese , Interleucina-2/biossíntese , Leucócitos Mononucleares/metabolismo , Ativação Linfocitária/efeitos dos fármacos , Subpopulações de Linfócitos/fisiologia , Masculino , Pessoa de Meia-Idade , Ácido alfa-Linolênico/administração & dosagem , Ácido alfa-Linolênico/farmacologia , Ácido gama-Linolênico/farmacologiaRESUMO
BACKGROUND: When using traditional microbiological techniques to monitor cell proliferation and viability, stressed, sublethally injured, or otherwise "viable but nonculturable" cells often go undetected. Because of this, such cells often are not considered by mathematical models used to predict bioprocess performance on scale-up and inaccuracies result. Therefore, analytical techniques, decoupled from postsampling growth, are desirable to rapidly monitor individual cell physiologic states during microbial fermentations. METHODS: Microbial cells, including Escherichia coli, Rhodococus sp., and Sacharomyces cerevisiae, were taken at various stages from a range of fermentation processes and stained with one of three mixtures of fluorescent stains: rhodamine 123/propidium iodide, bis-oxonol/propidium iodide, or bis-oxonol/ethidium bromide/propidium iodide. An individual cell's physiologic state was assessed with a Coulter Epics Elite analyzer based on the differential uptakes of these fluorescent stains. RESULTS: It was possible to resolve an individual cell's physiologic state beyond culturability based on the functionality of dye extrusion pumps and the presence or absence of an intact polarized cytoplasmic membrane, enabling assessment of population heterogeneity. This approach allows the simultaneous differentiation of at least four functional subpopulations in microbial populations. CONCLUSIONS: Fluorescent staining methods used in our laboratories have led to a functional classification of the physiological state of individual microbial cells based on reproductive activity, metabolic activity, and membrane integrity. We have used these techniques extensively for monitoring the stress responses of microorganisms in such diverse areas as bioremediation, biotransformation, food processing, and microbial fermentation; microbial fermentation is discussed in this article.
Assuntos
Citometria de Fluxo/métodos , Microbiologia Industrial/métodos , Fenômenos Fisiológicos Celulares , Escherichia coli/crescimento & desenvolvimento , Fermentação , Luz , Rhodococcus/crescimento & desenvolvimento , Saccharomyces cerevisiae/crescimento & desenvolvimentoRESUMO
Mast cells and immature dendritic cells (DC) are in close contact in peripheral tissues. Upon activation, mast cells release histamine, a mediator involved in the immediate hypersensitivity reaction. We therefore tested whether histamine could affect human DC activation and maturation. Histamine induces CD86 expression on immature DC in a dose-dependent (significant at 10(-7) M) and transient manner (maximal after 24-h stimulation). Histamine also transiently up-regulates the expression of the costimulatory and accessory molecules, CD40, CD49d, CD54, CD80, and MHC class II. As a consequence, immature DC exposed for 24 h to histamine stimulate memory T cells more efficiently than untreated DC. In addition, histamine induces a potent production of IL-6, IL-8, monocyte chemoattractant protein 1, and macrophage-inflammatory protein 1alpha by immature DC and also up-regulates IL-1beta, RANTES, and macrophage-inflammatory protein 1beta but not TNF-alpha and IL-12 mRNA expression. Histamine activates immature DC through both the H1 and H2 receptors. However, histamine-treated DC do not have a phenotype of fully mature cells, as they do neither show significant changes in the expression of the chemokine receptors, CCR5, CCR7 and CXC chemokine receptor 4, nor expression of CD83 de novo. These data demonstrate that histamine activates immature DC and induces chemokine production, thereby suggesting that histamine, via stimulation of resident DC, may participate locally in T cell stimulation and in the late inflammatory reaction associated with allergic disorders.
Assuntos
Antígenos CD/biossíntese , Quimiocinas/biossíntese , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Histamina/farmacologia , Glicoproteínas de Membrana/biossíntese , Adjuvantes Imunológicos/farmacologia , Apresentação de Antígeno/efeitos dos fármacos , Antígeno B7-1/biossíntese , Antígeno B7-2 , Antígenos CD40/biossíntese , Diferenciação Celular/imunologia , Células Cultivadas , Técnicas de Cocultura , Citocinas/biossíntese , Células Dendríticas/patologia , Relação Dose-Resposta Imunológica , Antígenos HLA-DR/biossíntese , Histamina/metabolismo , Histamina/fisiologia , Humanos , Integrina alfa4 , Integrinas/biossíntese , Molécula 1 de Adesão Intercelular/biossíntese , Receptores Histamínicos H1/fisiologia , Receptores Histamínicos H2/fisiologia , Regulação para Cima/imunologiaRESUMO
BACKGROUND: Animal studies showed that dietary flaxseed oil [rich in the n-3 polyunsaturated fatty acid alpha-linolenic acid (ALA)], evening primrose oil [rich in the n-6 polyunsaturated fatty acid gamma-linolenic acid (GLA)], and fish oil [rich in the long-chain n-3 polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] can decrease natural killer (NK) cell activity. There have been no studies of the effect on NK cell activity of adding these oils to the diet of humans. OBJECTIVE: Our objective was to determine the effect of dietary supplementation with oil blends rich in ALA, GLA, arachidonic acid (AA), DHA, or EPA plus DHA (fish oil) on the NK cell activity of human peripheral blood mononuclear cells. DESIGN: A randomized, placebo-controlled, double-blind, parallel study was conducted. Healthy subjects aged 55-75 y consumed 9 capsules/d for 12 wk; the capsules contained placebo oil (an 80:20 mix of palm and sunflower seed oils) or blends of placebo oil and oils rich in ALA, GLA, AA, DHA, or EPA plus DHA. Subjects in these groups consumed 2 g ALA, 770 mg GLA, 680 mg AA, 720 mg DHA, or 1 g EPA plus DHA (720 mg EPA + 280 mg DHA) daily, respectively. Total fat intake from the capsules was 4 g/d. RESULTS: The fatty acid composition of plasma phospholipids changed significantly in the GLA, AA, DHA, and fish oil groups. NK cell activity was not significantly affected by the placebo, ALA, GLA, AA, or DHA treatment. Fish oil caused a significant reduction (mean decline: 48%) in NK cell activity that was fully reversed by 4 wk after supplementation had ceased. CONCLUSION: A moderate amount of EPA but not of other n-6 or n-3 polyunsaturated fatty acids can decrease NK cell activity in healthy subjects.
Assuntos
Ácido Eicosapentaenoico/administração & dosagem , Células Matadoras Naturais/metabolismo , Idoso , Ácido Araquidônico/administração & dosagem , Suplementos Nutricionais , Ácidos Docosa-Hexaenoicos/administração & dosagem , Método Duplo-Cego , Ácido Eicosapentaenoico/farmacologia , Ácidos Graxos Ômega-3/administração & dosagem , Ácidos Graxos Ômega-6 , Ácidos Graxos Insaturados/administração & dosagem , Feminino , Óleos de Peixe/administração & dosagem , Humanos , Imunidade Celular/efeitos dos fármacos , Células Matadoras Naturais/efeitos dos fármacos , Subpopulações de Linfócitos/efeitos dos fármacos , Subpopulações de Linfócitos/metabolismo , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Ácido alfa-Linolênico/administração & dosagem , Ácido gama-Linolênico/administração & dosagemRESUMO
CD86 is a costimulatory molecule constitutively expressed by human antigen presenting cells which interacts with CD28 and CTLA-4 expressed by T cells. We have recently reported the identification of an alternatively spliced CD86 mRNA variant (CD86deltaTM) characterized by the deletion of exon 6 which encodes for the transmembrane domain. We report here the identification of an alternatively spliced variant (called CD86deltaEC) expressed by nonstimulated human monocytes and characterized by the deletion of exons 4 and 5 which encode for the extracellular V-like and C-like domains, respectively. The activation of monocytes by IFNgamma (i) induces the preferential expression of the transcript encoding for the membrane form and (ii) increases the expression of CD86 and of the accessory molecules CD40, CD49d and CD54. These results suggest that resting human monocytes may constitutively express different forms of CD86 which can then influence the activation of T cells.
Assuntos
Processamento Alternativo , Antígenos CD/genética , Glicoproteínas de Membrana/genética , RNA Mensageiro/genética , Sequência de Aminoácidos , Antígeno B7-2 , Sequência de Bases , Clonagem Molecular , DNA Complementar/química , DNA Complementar/genética , Regulação da Expressão Gênica , Humanos , Dados de Sequência Molecular , Monócitos/citologia , Monócitos/metabolismo , Análise de Sequência de DNARESUMO
Greatly increasing the amounts of flaxseed oil [rich in alpha-linolenic acid (ALNA)] or fish oil (FO); [rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] in the diet can decrease inflammatory cell functions and so might impair host defense. The objective of this study was to determine the effect of dietary supplementation with moderate levels of ALNA, gamma-linolenic acid (GLA), arachidonic acid (ARA), DHA, or FO on inflammatory cell numbers and functions and on circulating levels of soluble adhesion molecules. Healthy subjects aged 55 to 75 yr consumed nine capsules per day for 12 wk. The capsules contained placebo oil (an 80:20 mix of palm and sunflowerseed oils) or blends of placebo oil with oils rich in ALNA, GLA, ARA, or DHA or FO. Subjects in these groups consumed 2 g ALNA; approximately 700 mg GLA, ARA, or DHA; or 1 g EPA plus DHA (720 mg EPA + 280 mg DHA) daily from the capsules. Total fat intake from the capsules was 4 g per day. None of the treatments affected inflammatory cell numbers in the bloodstream; neutrophil and monocyte phagocytosis or respiratory burst in response to E. coli; production of tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6 in response to bacterial lipopolysaccharide; or plasma concentrations of soluble intercellular adhesion molecule-1. In contrast, the ALNA and FO treatments decreased the plasma concentrations of soluble vascular cell adhesion molecule-1 (16 and 28% decrease, respectively) and soluble E-selectin (23 and 17% decrease, respectively). It is concluded that, in contrast to previous reports using higher amounts of these fatty acids, a moderate increase in consumption of long-chain n-6 or n-3 polyunsaturated fatty acids does not significantly affect inflammatory cell numbers or neutrophil and monocyte responses in humans and so would not be expected to cause immune impairment. Furthermore, we conclude that moderate levels of ALNA and FO, which could be incorporated into the diet, can decrease some markers of endothelial activation and that this mechanism of action may contribute to the reported health benefits of n-3 fatty acids.