Dopamine up-regulates Th17 phenotype from individuals with generalized anxiety disorder

AbstractOur objective was to evaluate the effect of stress-related dose of dopamine (DA) on the in vitro proliferation and cytokine production in polyclonally-activated T cells from healthy individuals or individuals with generalized anxiety disorder (GAD). Our results demonstrated that cell cultures from GAD group proliferated less following T cell activation, as compared with control group. The addition of DA reduced the proliferative response in cell cultures from healthy but not from GAD individuals. The cytokine profile in GAD individuals revealed Th1 and Th2 deficiencies associated with a dominant Th17 phenotype, which was enhanced by DA. A similar DA-induced immunomodulation was also observed in PPD-activated cell cultures from GAD individuals. Unlike the control, DA-enhanced Th17 cytokine production in GAD individuals was not affected by glucocorticoid. In conclusion, our results show that the T cell functional dysregulation in GAD individuals is significantly amplified by DA. These immune abnormalities can have impact in increasing the susceptibility of individuals with anxiety disorders to infectious diseases and inflammatory/autoimmune disorders

Biochemical characterization of potential virulence markers in the human fungal pathogen Pseudallescheria boydii

The ubiquitous Pseudallescheria boydii (anamorph Scedosporium apiospermum) is a saprophytic filamentous fungus recognized as a potent etiologic agent of a wide variety of infections in immunocompromised as well as in immunocompetent patients. Very little is known about the virulence factors expressed by this fungal pathogen. The present review provides an overview of recent discoveries related to the identification and biochemical characterization of potential virulence attributes produced by P. boydii, with special emphasis on surface and released molecules. These structures include polysaccharides (glucans), glycopeptides (peptidorhamnomannans), glycolipids (glucosylceramides) and hydrolytic enzymes (proteases, phosphatases and superoxide dismutase), which have been implicated in some fundamental cellular processes in P. boydii including growth, differentiation and interaction with host molecules. Elucidation of the structure of cell surface components as well as the secreted molecules, especially those that function as virulence determinants, is of great relevance to understand the pathogenic mechanisms of P. boydii

Monoclonal Antibodies Against Peptidorhamnomannans of Scedosporium apiospermum Enhance the Pathogenicity of the Fungus

Scedosporium apiospermum is part of the Pseudallescheria-Scedosporium complex. Peptidorhamnomannans (PRMs) are cell wall glycopeptides present in some fungi, and their structures have been characterized in S. apiospermum, S. prolificans and Sporothrix schenckii. Prior work shows that PRMs can interact with host cells and that the glycopeptides are antigenic. In the present study, three monoclonal antibodies (mAbs, IgG1) to S. apiospermum derived PRM were generated and their effects on S. apiospermum were examined in vitro and in vivo. The mAbs recognized a carbohydrate epitope on PRM. In culture, addition of the PRM mAbs increased S. apiospermum conidia germination and reduced conidial phagocytosis by J774.16 macrophages. In a murine infection model, mice treated with antibodies to PRM died prior to control animals. Thus, PRM is involved in morphogenesis and the binding of this glycopeptide by mAbs enhanced the virulence of the fungus. Further insights into the effects of these glycopeptides on the pathobiology of S. apiospermum may lead to new avenues fo

O-glycosylation in cell wall proteins in Scedosporium prolificans is critical for phagocytosis and inflammatory cytokines production by macrophages.

In this study, we analyze the importance of O-linked oligosaccharides present in peptidorhamnomannan (PRM) from the cell wall of the fungus Scedosporium prolificans for recognition and phagocytosis of conidia by macrophages. Adding PRM led to a dose-dependent inhibition of conidia phagocytosis, whereas de-O-glycosylated PRM did not show any effect. PRM induced the release of macrophage-derived antimicrobial compounds. However, O-linked oligosaccharides do not appear to be required for such induction. The effect of PRM on conidia-induced macrophage killing was examined using latex beads coated with PRM or de-O-glycosylated PRM. A decrease in macrophage viability similar to that caused by conidia was detected. However, macrophage killing was unaffected when beads coated with de-O-glycosylated PRM were used, indicating the toxic effect of O-linked oligosaccharides on macrophages. In addition, PRM triggered TNF-α release by macrophages. Chemical removal of O-linked oligosaccharides from PRM abolished cytokine induction, suggesting that the O-linked oligosaccharidic chains are important moieties involved in inflammatory responses through the induction of TNF-α secretion. In summary, we show that O-glycosylation plays a role in the recognition and uptake of S. prolificans by macrophages, killing of macrophages and production of pro- inflammatory cytokines

Cytokine release induced by conidia and PRM from <i>S</i>. <i>prolificans</i>.

<p>(<b>A</b>) <i>O</i>-linked oligosaccharidic chains are crucial to the production of TNF-α. Both <i>S</i>. <i>prolificans</i> conidia and PRM were able to stimulate the production of TNF-α. This effect was abolished when the <i>O</i>-linked oligosaccharides were removed from PRM molecules. (<b>B</b>). <i>S</i>. <i>prolificans</i> conidia were able to stimulate the production of IL-10, but this effect was independent of PRM. Values are the means of three independent experiments. Asterisks denote values significantly different from control (** P = 0.002; *** P < 0.001).</p

Evaluation of macrophages viability.

<p>(<b>A</b>) <i>S</i>. <i>prolificans</i> conidia cells are able to kill macrophages during the first hour of interaction. (<b>B</b>) Cytotoxicity of soluble PRM accessed by the neutral red dye-uptake method on macrophages during 24 h of incubation was measured by the absorbance measured at 490 nm in a spectrophotometer. (<b>C</b>) Beads coated with PRM and de-<i>O</i>-PRM showed that <i>O</i>-linked oligosaccharides are responsible for the toxic effects of PRM on macrophages. Values are the means of three independent experiments. Asterisks denote values significantly different from control (* P < 0.05; *** P < 0.001).</p

PRM is on the fungal cell surface.

<p>Immune serum was able to bind to <i>S</i>. <i>prolificans</i> conidial forms (<b>Aa and Ab</b>), but pre-incubation with soluble pRM was able to inhibit the binding between <i>S</i>. <i>prolificans</i> conidia cells and immune serum (<b>Ac and Ad</b>), as observed by immunofluorescence microcopy. A similar data was observed by flow cytometry showing that conidia fluorescence is practically abolished when serum is pre-treated with PRM (<b>B</b>). Bar: 10 μm.</p

Effect of <i>O</i>-glycosylation on the release of nitric oxide (NO).

<p><i>S</i>. <i>prolificans</i> conidia and PRM led to a significant increase in the levels of NO during interaction with macrophages. <i>O</i>-linked oligosaccharides structures were not required for such induction, as observed in the graphs. Values are the means of three independent experiments. Asterisks denote values significantly different from control (*** P < 0.001).</p