RESUMEN

Sepsis is controlled by endogenous glucocorticoids (GCs). Previous studies provided evidence that crosstalk of the monomeric GC receptor (GR) with proinflammatory transcription factors is the crucial mechanism underlying the suppressive GC effect. Here we demonstrate that mice with a dimerization-deficient GR (GR(dim)) are highly susceptible to sepsis in 2 different models, namely cecal ligation and puncture and lipopolysaccharide (LPS)-induced septic shock. TNF-α is normally regulated in these mice, but down-regulation of IL-6 and IL-1ß is diminished. LPS-treated macrophages derived from GR(dim) mice are largely resistant to GC actions in vitro in terms of morphology, surface marker expression, and gene expression. Treatment with recombinant IL-1 receptor antagonist improved survival of GR(dim) mice and mice lacking the GR in macrophages (GR(LysMCre)) mice. This suggests that regulation of IL-1ß in macrophages by GCs is pivotal to control sepsis.

Asunto(s)

Interleucina-1beta/metabolismo , Macrófagos/metabolismo , Receptores de Glucocorticoides/química , Receptores de Glucocorticoides/metabolismo , Choque Séptico/metabolismo , Animales , Dexametasona/farmacología , Dimerización , Modelos Animales de Enfermedad , Regulación hacia Abajo , Interleucina-1beta/genética , Interleucina-6/genética , Interleucina-6/metabolismo , Lipopolisacáridos/toxicidad , Macrófagos/efectos de los fármacos , Ratones , Ratones de la Cepa 129 , Ratones Endogámicos C57BL , Ratones Transgénicos , Mutación , Estructura Cuaternaria de Proteína , ARN/química , ARN/genética , ARN/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Receptores de Glucocorticoides/genética , Receptores de Interleucina-1/antagonistas & inhibidores , Choque Séptico/genética , Transducción de Señal , Transcriptoma , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/metabolismo

RESUMEN

Glucocorticoids (GCs) are widely used in the treatment of allergic skin conditions despite having numerous side effects. Here we use Cre/loxP-engineered tissue- and cell-specific and function-selective GC receptor (GR) mutant mice to identify responsive cell types and molecular mechanisms underlying the antiinflammatory activity of GCs in contact hypersensitivity (CHS). CHS was repressed by GCs only at the challenge phase, i.e., during reexposure to the hapten. Inactivation of the GR gene in keratinocytes or T cells of mutant mice did not attenuate the effects of GCs, but its ablation in macrophages and neutrophils abolished downregulation of the inflammatory response. Moreover, mice expressing a DNA binding-defective GR were also resistant to GC treatment. The persistent infiltration of macrophages and neutrophils in these mice is explained by an impaired repression of inflammatory cytokines and chemokines such as IL-1beta, monocyte chemoattractant protein-1, macrophage inflammatory protein-2, and IFN-gamma-inducible protein 10. In contrast TNF-alpha repression remained intact. Consequently, injection of recombinant proteins of these cytokines and chemokines partially reversed suppression of CHS by GCs. These studies provide evidence that in contact allergy, therapeutic action of corticosteroids is in macrophages and neutrophils and that dimerization GR is required.

Asunto(s)

Dermatitis Alérgica por Contacto/tratamiento farmacológico , Dermatitis Alérgica por Contacto/inmunología , Dexametasona/administración & dosificación , Inmunosupresores/uso terapéutico , Macrófagos/efectos de los fármacos , Neutrófilos/efectos de los fármacos , Animales , Antiinflamatorios/uso terapéutico , Células Cultivadas , Dermatitis Alérgica por Contacto/patología , Dexametasona/uso terapéutico , Sistemas de Liberación de Medicamentos , Macrófagos/inmunología , Macrófagos/patología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Transgénicos , Neutrófilos/inmunología , Neutrófilos/patología , Receptores de Glucocorticoides/antagonistas & inhibidores , Receptores de Glucocorticoides/genética

RESUMEN

We describe a proteomic approach for identifying bacterial surface-exposed proteins quickly and reliably for their use as vaccine candidates. Whole cells are treated with proteases to selectively digest protruding proteins that are subsequently identified by mass spectrometry analysis of the released peptides. When applied to the sequenced M1_SF370 group A Streptococcus strain, 68 PSORT-predicted surface-associated proteins were identified, including most of the protective antigens described in the literature. The number of surface-exposed proteins varied from strain to strain, most likely as a consequence of different capsule content. The surface-exposed proteins of the highly virulent M23_DSM2071 strain included 17 proteins, 15 in common with M1_SF370. When 14 of the 17 proteins were expressed in E. coli and tested in the mouse for their capacity to confer protection against a lethal dose of M23_DSM2071, one new protective antigen (Spy0416) was identified. This strategy overcomes the difficulties so far encountered in surface protein characterization and has great potential in vaccine discovery.

Asunto(s)

Vacunas Bacterianas/análisis , Vacunas Bacterianas/inmunología , Proteínas de la Membrana/análisis , Proteínas de la Membrana/inmunología , Proteoma/análisis , Infecciones Estreptocócicas/inmunología , Streptococcus pyogenes/metabolismo , Secuencia de Aminoácidos , Animales , Antígenos Bacterianos/análisis , Antígenos Bacterianos/química , Antígenos Bacterianos/inmunología , Vacunas Bacterianas/química , Vacunas Bacterianas/uso terapéutico , Sistemas de Liberación de Medicamentos/métodos , Diseño de Fármacos , Espectrometría de Masas/métodos , Proteínas de la Membrana/química , Ratones , Datos de Secuencia Molecular , Mapeo Peptídico/métodos , Proteoma/química , Proteoma/inmunología , Infecciones Estreptocócicas/prevención & control , Streptococcus pyogenes/inmunología

RESUMEN

Using electron diffraction on freestanding single-walled carbon nanotubes, we have determined the structural indices (n,m) of tubes in the diameter range from 1.4 to 3 nm. On the same freestanding tubes, we have recorded Raman spectra of the tangential modes and the radial breathing mode. For the smaller diameters (1.4-1.7 nm), these measurements confirm previously established radial breathing mode frequency versus diameter relations and would be consistent with the theoretically predicted proportionality to the inverse diameter. However, for extending the relation to larger diameters, either a yet unexplained environmental constant has to be assumed, or the linear relation has to be abandoned.