RESUMEN
BACKGROUND: Prostaglandin D2 (PGD2) and cysteinyl leukotrienes (cysLTs) are lipid mediators derived from mast cells, which activate TH2 cells. The combination of PGD2 and cysLTs (notably cysteinyl leukotriene E4 [LTE4]) enhances TH2 cytokine production. However, the synergistic interaction of cysLTs with PGD2 in promoting TH2 cell activation is still poorly understood. The receptors for these mediators are drug targets in the treatment of allergic diseases, and hence understanding their interaction is likely to have clinical implications. OBJECTIVE: We aimed to comprehensively define the roles of PGD2, LTE4, and their combination in activating human TH2 cells and how such activation might allow the TH2 cells to engage downstream effectors, such as neutrophils, which contribute to the pathology of allergic responses. METHODS: The effects of PGD2, LTE4, and their combination on human TH2 cell gene expression were defined by using a microarray, and changes in specific inflammatory pathways were confirmed by means of PCR array, quantitative RT-PCR, ELISA, Luminex, flow cytometry, and functional assays, including analysis of downstream neutrophil activation. Blockade of PGD2 and LTE4 was tested by using TM30089, an antagonist of chemoattractant receptor-homologous molecule expressed on TH2 cells, and montelukast, an antagonist of cysteinyl leukotriene receptor 1. RESULTS: PGD2 and LTE4 altered the transcription of a wide range of genes and induced diverse functional responses in TH2 cells, including cell adhesion, migration, and survival and cytokine production. The combination of these lipids synergistically or additively enhanced TH2 responses and, strikingly, induced marked production of diverse nonclassical TH2 inflammatory mediators, including IL-22, IL-8, and GM-CSF, at concentrations sufficient to affect neutrophil activation. CONCLUSIONS: PGD2 and LTE4 activate TH2 cells through different pathways but act synergistically to promote multiple downstream effector functions, including neutrophil migration and survival. Combined inhibition of both PGD2 and LTE4 pathways might provide an effective therapeutic strategy for allergic responses, particularly those involving interaction between TH2 cells and neutrophils, such as in patients with severe asthma.
Asunto(s)
Comunicación Celular/inmunología , Leucotrieno E4/metabolismo , Neutrófilos/inmunología , Neutrófilos/metabolismo , Prostaglandina D2/metabolismo , Células Th2/inmunología , Células Th2/metabolismo , Apoptosis/efectos de los fármacos , Apoptosis/inmunología , Moléculas de Adhesión Celular/genética , Moléculas de Adhesión Celular/metabolismo , Comunicación Celular/efectos de los fármacos , Comunicación Celular/genética , Quimiotaxis de Leucocito/efectos de los fármacos , Quimiotaxis de Leucocito/genética , Quimiotaxis de Leucocito/inmunología , Análisis por Conglomerados , Sinergismo Farmacológico , Expresión Génica , Perfilación de la Expresión Génica , Humanos , Mediadores de Inflamación/metabolismo , Leucotrieno E4/farmacología , Neutrófilos/efectos de los fármacos , Prostaglandina D2/farmacología , Células Th2/efectos de los fármacosRESUMEN
PGD(2) exerts a number of proinflammatory responses through a high-affinity interaction with chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2) and has been detected at high concentrations at sites of allergic inflammation. Because cysteinyl leukotrienes (cysLTs) are also produced during the allergic response, we investigated the possibility that cysLTs may modulate the response of human Th2 cells to PGD(2). PGD(2) induced concentration-dependent Th2 cytokine production in the absence of TCR stimulation. Leukotrienes D(4) and E(4) (LTE(4)) also stimulated the cytokine production but were much less active than PGD(2). However, when combined with PGD(2), cysLTs caused a greater than additive enhancement of the response, with LTE(4) being most effective in activating Th2 cells. LTE(4) enhanced calcium mobilization in response to PGD(2) in Th2 cells without affecting endogenous PGD(2) production or CRTH2 receptor expression. The effect of LTE(4) was inhibited by montelukast but not by the P2Y(12) antagonist methylthioadenosine 5'-monophosphate. The enhancing effect was also evident with endogenous cysLTs produced from immunologically activated mast cells because inhibition of cysLT action by montelukast or cysLT synthesis by MK886, an inhibitor of 5-lipoxygenase-activating protein, reduced the response of Th2 cells to the levels produced by PGD(2) alone. These findings reveal that cysLTs, in particular LTE(4), have a significant proinflammatory impact on T cells and demonstrate their effects on Th2 cells are mediated by a montelukast-sensitive receptor.
Asunto(s)
Citocinas/biosíntesis , Leucotrieno E4/fisiología , Activación de Linfocitos/inmunología , Prostaglandina D2/fisiología , Células Th2/inmunología , Células Th2/patología , Animales , Células CHO , Células Cultivadas , Cricetinae , Sinergismo Farmacológico , Humanos , Inflamación/inmunología , Inflamación/metabolismo , Inflamación/patología , Mastocitos/inmunología , Mastocitos/metabolismo , Células Th2/metabolismoRESUMEN
BACKGROUND: Isolated reactive serum treponemal chemiluminescence immunoassay (CIA) specimens cause clinical uncertainty. METHODS: Sera were screened by CIA, and reactive samples underwent reflex testing with rapid plasma reagin (RPR), Treponema pallidum particle agglutination (TPPA), and fluorescent treponemal antibody absorption (FTA Abs) assays. Samples reactive only on the CIA were deemed "isolated" reactive CIA samples. We undertook detailed review of a subset of subjects with isolated reactive CIA specimens. RESULTS: Of 28 261 specimens, 1171 (4.1%) were reactive on CIA, of which 133 (11.3%) had isolated CIA reactivity. Most subjects (66 of 82 [80.5%]) with isolated reactive CIA specimens were from high-prevalence populations. We found evidence of CIA, TPPA, and FTA Abs seroreversion. The median chemiluminescent signal-to-cutoff ratio was similar for isolated reactive CIA sera and sera that were reactive on either FTA Abs or TPPA assays (2.19 vs 2.32; P = .15) but lower than for sera reactive on both FTA Abs and TPPA assays (12.37; P < .001) or for sera reactive on RPR assays (25.53; P < .001). A total of 11 of 20 patients (55%) with an isolated reactive CIA specimen who underwent medical record review had previous or subsequent evidence of syphilis infection. CONCLUSIONS: Isolated reactive CIA specimens may represent true T. pallidum infection and may be found after seroreversion of traditional treponemal assays.
Asunto(s)
Luminiscencia , Serodiagnóstico de la Sífilis/métodos , Sífilis/diagnóstico , Treponema pallidum/inmunología , Adulto , Anciano , Femenino , Humanos , Recién Nacido , Masculino , Persona de Mediana Edad , Embarazo , Adulto JovenRESUMEN
D prostanoid receptor 2 (DP2) [also known as chemoattractant receptor-homologous molecule expressed on T helper 2 (Th2) cells (CRTH2)] is selectively expressed by Th2 lymphocytes, eosinophils, and basophils and mediates recruitment and activation of these cell types in response to prostaglandin D2 (PGD2). (5-Fluoro-2-methyl-3-quinolin-2-ylmethylindo-1-yl)-acetic acid (OC000459) is an indole-acetic acid derivative that potently displaces [³H]PGD2 from human recombinant DP2 (K(i) = 0.013 µM), rat recombinant DP2 (K(i) = 0.003 µM), and human native DP2 (Th2 cell membranes; K(i) = 0.004 µM) but does not interfere with the ligand binding properties or functional activities of other prostanoid receptors (prostaglandin E1â4 receptors, D prostanoid receptor 1, thromboxane receptor, prostacyclin receptor, and prostaglandin F receptor). OC000459 inhibited chemotaxis (IC50 = 0.028 µM) of human Th2 lymphocytes and cytokine production (IC50 = 0.019 µM) by human Th2 lymphocytes. OC000459 competitively antagonized eosinophil shape change responses induced by PGD2 in both isolated human leukocytes (pK(B) = 7.9) and human whole blood (pK(B) = 7.5) but did not inhibit responses to eotaxin, 5-oxo-eicosatetraenoic acid, or complement component C5a. OC000459 also inhibited the activation of Th2 cells and eosinophils in response to supernatants from IgE/anti-IgE-activated human mast cells. OC000459 had no significant inhibitory activity on a battery of 69 receptors and 19 enzymes including cyclooxygenase 1 (COX1) and COX2. OC000459 was found to be orally bioavailable in rats and effective in inhibiting blood eosinophilia induced by 13,14-dihydro-15-keto-PGD2 (DK-PGD2) in this species (ED50 = 0.04 mg/kg p.o.) and airway eosinophilia in response to an aerosol of DK-PGD2 in guinea pigs (ED50 = 0.01 mg/kg p.o.). These data indicate that OC000459 is a potent, selective, and orally active DP2 antagonist that retains activity in human whole blood and inhibits mast cell-dependent activation of both human Th2 lymphocytes and eosinophils.
Asunto(s)
Eosinófilos/efectos de los fármacos , Ácidos Indolacéticos/farmacología , Activación de Linfocitos/efectos de los fármacos , Mastocitos/inmunología , Antagonistas de Prostaglandina/farmacología , Quinolinas/farmacología , Receptores Inmunológicos/metabolismo , Receptores de Prostaglandina/metabolismo , Células Th2/efectos de los fármacos , Animales , Apoptosis/efectos de los fármacos , Ácidos Araquidónicos/farmacología , Unión Competitiva , Células CHO , Señalización del Calcio/efectos de los fármacos , Membrana Celular/metabolismo , Forma de la Célula/efectos de los fármacos , Forma de la Célula/inmunología , Quimiocina CCL11/farmacología , Quimiotaxis/efectos de los fármacos , Quimiotaxis/inmunología , Complemento C5a/farmacología , Cricetinae , Medios de Cultivo Condicionados/farmacología , Eosinofilia/inducido químicamente , Eosinofilia/prevención & control , Eosinófilos/citología , Eosinófilos/inmunología , Cobayas , Humanos , Ácidos Indolacéticos/farmacocinética , Ácidos Indolacéticos/uso terapéutico , Interleucina-13/metabolismo , Interleucina-5/farmacología , Leucotrieno B4/farmacología , Activación de Linfocitos/inmunología , Mastocitos/metabolismo , Antagonistas de Prostaglandina/farmacocinética , Antagonistas de Prostaglandina/uso terapéutico , Prostaglandina D2/análogos & derivados , Prostaglandina D2/metabolismo , Prostaglandina D2/farmacología , Eosinofilia Pulmonar/inducido químicamente , Eosinofilia Pulmonar/prevención & control , Quinolinas/farmacocinética , Quinolinas/uso terapéutico , Ensayo de Unión Radioligante , Ratas , Ratas Sprague-Dawley , Receptores Inmunológicos/genética , Receptores de Prostaglandina/genética , Proteínas Recombinantes/metabolismo , Células Th2/citología , Células Th2/inmunología , Células Th2/metabolismo , TransfecciónRESUMEN
G-protein-coupled receptors are not only highly tractable drug targets but also attractive candidates for genetic association studies because they are more polymorphic than most other classes of gene and these polymorphisms frequently lead to functional changes in the levels of expression or biological activity that can predispose to common diseases. A large-scale study to identify functional variants in G-protein-coupled receptors associated with inflammatory diseases has highlighted a spectrum of novel biological insights that range from identifying the involvement of orphan receptors in certain diseases through to highlighting new therapeutic indications for existing drugs.
Asunto(s)
Predisposición Genética a la Enfermedad/genética , Inflamación/tratamiento farmacológico , Receptores Acoplados a Proteínas G/genética , Antiinflamatorios/uso terapéutico , Diseño de Fármacos , Humanos , Inflamación/genética , Inflamación/inmunología , Polimorfismo Genético , Receptores Acoplados a Proteínas G/agonistas , Receptores Acoplados a Proteínas G/antagonistas & inhibidores , Tecnología Farmacéutica/métodos , Tecnología Farmacéutica/tendenciasRESUMEN
Prostaglandin D2 (PGD2) acting at the CRTH2 receptor (chemoattractant receptor-homologous molecule expressed on Th2 cells) has been linked with a variety of allergic and other inflammatory diseases. We describe a family of indole-1-sulfonyl-3-acetic acids that are potent and selective CRTH2 antagonists that possess good oral bioavailability. The compounds may serve as novel starting points for the development of treatments of inflammatory disease such as asthma, allergic rhinitis, and atopic dermatitis.
Asunto(s)
Antiinflamatorios no Esteroideos/síntesis química , Ácidos Indolacéticos/síntesis química , Receptores Inmunológicos/antagonistas & inhibidores , Receptores de Prostaglandina/antagonistas & inhibidores , Animales , Antiinflamatorios no Esteroideos/farmacocinética , Antiinflamatorios no Esteroideos/farmacología , Disponibilidad Biológica , Células CHO , Calcio/metabolismo , Cricetinae , Cricetulus , Humanos , Ácidos Indolacéticos/farmacocinética , Ácidos Indolacéticos/farmacología , Prostaglandina D2/farmacología , Ratas , Relación Estructura-Actividad , Sulfonas/síntesis química , Sulfonas/farmacocinética , Sulfonas/farmacologíaRESUMEN
BACKGROUND: HIV-positive adults are at risk of vaccine preventable infections including Streptococcus pneumoniae, hepatitis A virus (HAV) and hepatitis B virus (HBV). Uptake of immunisations in HIV patients is suboptimal despite evidence of efficacy. METHODS: An audit was made of the vaccination records in 200 adult HIV-positive regular clinic attendees, with a CD4+ count >200 cells µL(-1). RESULTS: Medical records or laboratory data revealed that 10% had been vaccinated against S. pneumoniae; 74% were immune or immunised against HAV; 40% had evidence of natural infection with HBV and 84% of nonimmune patients had been vaccinated. CONCLUSIONS: Strategies to improve vaccine uptake are required.
Asunto(s)
Infecciones Oportunistas Relacionadas con el SIDA/prevención & control , Instituciones de Atención Ambulatoria , Vacunas contra la Hepatitis A/administración & dosificación , Hepatitis A/prevención & control , Vacunas contra Hepatitis B/administración & dosificación , Hepatitis B/prevención & control , Auditoría Médica , Infecciones Neumocócicas/prevención & control , Vacunas Neumococicas/administración & dosificación , Infecciones Oportunistas Relacionadas con el SIDA/epidemiología , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Nueva Gales del Sur , Vacunas Combinadas/administración & dosificación , Adulto JovenRESUMEN
BACKGROUND: Lupus nephritis encompasses a wide range of parenchymal injuries and severity. Better predictors of outcome are needed for patients newly diagnosed with lupus nephritis, so that an appropriate management strategy may be selected. METHODS: A single-center cohort of first renal biopsies for lupus nephritis was chosen. Histologic sections of whole biopsy cores were stained with picro-Sirius red, and light microscopic images (x100) were digitally captured. Using a simple, freely available software package, the cortex of each biopsy was evaluated for four different parameters: area occupied by nuclei, intratubular space, fibrillary collagen, and collagenous matrix. Clinical and laboratory data were collected retrospectively from the time of biopsy and throughout follow-up. RESULTS: A high nuclear index at initial biopsy correlated with clinical parameters of disease activity, at the time of biopsy. High collagen matrix index predicted both relapse and progression to end-stage renal disease (ESRD). The fibrillary collagen index predicted progressive disease as assessed by doubling of serum creatinine, and relapse. Increased tubular space also predicted progressive disease as determined by doubling of creatinine and renal death. CONCLUSION: A simple automated system for objectively scoring biopsies of lupus nephritis predicts renal survival and may provide a useful adjunct to guide patient management.
Asunto(s)
Colágeno/metabolismo , Nefritis Lúpica/metabolismo , Nefritis Lúpica/patología , Adulto , Biopsia , Estudios de Cohortes , Creatinina/metabolismo , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Inflamación/patología , Fallo Renal Crónico/etiología , Túbulos Renales/patología , Nefritis Lúpica/complicaciones , Nefritis Lúpica/mortalidad , Masculino , Persona de Mediana Edad , Pronóstico , Análisis de SupervivenciaRESUMEN
PGD2, produced by mast cells, has been detected in high concentrations at sites of allergic inflammation. It can stimulate vascular and other inflammatory responses by interaction with D prostanoid receptor (DP) and chemoattractant receptor-like molecule expressed on Th2 cells (CRTH2) receptors. A significant role for PGD2 in mediating allergic responses has been suggested based on the observation that enhanced eosinophilic lung inflammation and cytokine production is apparent in the allergen-challenged airways of transgenic mice overexpressing human PGD2 synthase, and PGD2 can enhance Th2 cytokine production in vitro from CD3/CD28-costimulated Th2 cells. In the present study, we investigated whether PGD2 has the ability to stimulate Th2 cytokine production in the absence of costimulation. At concentrations found at sites of allergic inflammation, PGD2 preferentially elicited the production of IL-4, IL-5, and IL-13 by human Th2 cells in a dose-dependent manner without affecting the level of the anti-inflammatory cytokine IL-10. Gene transcription peaked within 2 h, and protein release peaked approximately 8 h after stimulation. The effect of PGD2 was mimicked by the selective CRTH2 agonist 13,14-dihydro-15-keto-PGD2 but not by the selective DP agonist BW245C, suggesting that the stimulation is mediated by CRTH2 and not DP. Ramatroban, a dual CRTH2/thromboxane-like prostanoid receptor antagonist, markedly inhibited Th2 cytokine production induced by PGD2, while the selective thromboxane-like prostanoid receptor antagonist SQ29548 was without effect. These data suggest that PGD2 preferentially up-regulates proinflammatory cytokine production in human Th2 cells through a CRTH2-dependent mechanism in the absence of any other costimulation and highlight the potential utility of CRTH2 antagonists in the treatment of allergic diseases.
Asunto(s)
Citocinas/biosíntesis , Mediadores de Inflamación/metabolismo , Prostaglandina D2/farmacología , Receptores Inmunológicos/efectos de los fármacos , Receptores Inmunológicos/metabolismo , Receptores de Prostaglandina/efectos de los fármacos , Receptores de Prostaglandina/metabolismo , Células Th2/efectos de los fármacos , Células Th2/inmunología , Secuencia de Bases , Compuestos Bicíclicos Heterocíclicos con Puentes , Carbazoles/farmacología , Células Cultivadas , ADN/genética , Ácidos Grasos Insaturados , Humanos , Hidantoínas/farmacología , Hidrazinas/farmacología , Inflamación/tratamiento farmacológico , Inflamación/inmunología , Interleucina-13/biosíntesis , Interleucina-13/genética , Interleucina-4/biosíntesis , Interleucina-4/genética , Interleucina-5/biosíntesis , Interleucina-5/genética , Prostaglandina D2/análogos & derivados , Receptores Inmunológicos/agonistas , Receptores Inmunológicos/antagonistas & inhibidores , Receptores de Prostaglandina/agonistas , Receptores de Prostaglandina/antagonistas & inhibidores , Sulfonamidas/farmacología , Células Th2/metabolismo , Regulación hacia Arriba/efectos de los fármacosRESUMEN
Lipid A is the hydrophobic anchor of lipopolysaccharide (LPS) and forms the major lipid component of the outer monolayer of the outer membrane of gram-negative bacteria. Lipid A is required for bacterial growth and virulence, and inhibition of its biosynthesis is lethal to bacteria. UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase (LpxC) is a metalloenzyme that catalyzes the second step in the biosynthesis of lipid A. Inhibitors of LpxC have previously been shown to have antibiotic activities. We have screened a metalloenzyme inhibitor library for antibacterial activities against an Escherichia coli strain with reduced LpxC activity. From this screen, a series of sulfonamide derivatives of the alpha-(R)-amino hydroxamic acids, exemplified by BB-78484 and BB-78485, have been identified as having potent inhibitory activities against LpxC in an in vitro assay. Leads from this series showed gram-negative selective activities against members of the Enterobacteriaceae, Serratia marcescens, Morganella morganii, Haemophilus influenzae, Moraxella catarrhalis, and Burkholderia cepacia. BB-78484 was bactericidal against E. coli, achieving 3-log killing in 4 h at a concentration 4 times above the MIC, as would be predicted for an inhibitor of lipid A biosynthesis. E. coli mutants with decreased susceptibility to BB-78484 were selected. Analysis of these mutants revealed that resistance arose as a consequence of mutations in the fabZ or lpxC genes. These data confirm the antibacterial target of BB-78484 and BB-78485 and validate LpxC as a target for gram-negative selective antibacterials.