Blockades of phospholipase A2 and platelet-activating factor receptors reduce the hemocyte phagocytosis in Rhodnius prolixus: In vitro experiments

Figueiredo, Marcela B.; Garcia, Elói S.; Azambuja, Patrı́cia

doi:10.1016/j.jinsphys.2007.10.004

Cited by 30 publications

(14 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This group also recognized the actions of another lipid mediator, platelet-activating factor, in R. prolixus hemocyte microaggregation reactions to T. rangeli infection [48] . In later work, they noted that both eicosanoids and platelet-activating factor act in R. prolixus hemocyte phagocytosis [49] . Their work is important because it expands the range of lipid mediators known to act in insect immunity.…”

Section: Protozoansmentioning

confidence: 98%

Eicosanoid Actions in Insect Immunity

2009

View full text Add to dashboard Cite

Insects express 3 lines of protection from infections and invasions. Their cuticles and peritrophic membranes are physical barriers. Infections and invasions are quickly recognized within insect bodies, and recognition launches 2 lines of innate immune reactions. Humoral reactions involve induced synthesis of antimicrobial peptides, the bacteriolytic enzyme lysozyme and activation of the prophenoloxidase system. Cellular immune reactions include phagocytosis, nodulation and encapsulation. These reactions entail direct interactions between circulating hemocytes and the invaders. Cellular immune reactions begin immediately after an invasion is detected while antimicrobial peptides typically appear in the hemolymph some hours after infection. Microaggregation is a step in the nodulation process, which is responsible for clearing the bulk of bacterial infections from circulation. Coordinated cellular actions lead to encapsulation of invaders, such as parasitoid eggs, that are very much larger than individual hemocytes. In this paper, we review the roles of eicosanoids as central mediators of insect immune reactions, particularly cellular reactions. We briefly describe insect immune functions, outline eicosanoid biosynthesis and treat eicosanoid actions in cellular immunity of insects. Eicosanoids act in several cellular defense functions, including phagocytosis, microaggregation, nodulation, encapsulation, cell spreading and hemocyte migration toward a source of a bacterial peptide. We also describe our most recent work on the influence of one group of eicosanoids, prostaglandins, on gene expression in an established insect cell line.

show abstract

Section: Protozoansmentioning

confidence: 98%

Eicosanoid Actions in Insect Immunity

2009

View full text Add to dashboard Cite

show abstract

“…The most exciting outcome in the investigation of T. rangeli in triatomines is the PAF influence on the hemocyte nodulation [ 79 ] and phagocytic responses of R. prolixus hemocytes against Saccharomyces cerevisiae [ 66 , 67 ]. These authors evaluated the effects of PAF and eicosanoids in the phagocytosis in hemocyte monolayers (the main cell type implicated in this process is plasmatocytes) of R. prolixus against the yeast S. cerevisiae .…”

Section: Trypanosoma Rangeli Infection and Rhodniumentioning

confidence: 99%

“…Phagocytosis decreases expressively in hemocyte monolayers treated with WEB 2086, a specific PAF receptor antagonist. Nevertheless, a decrease of phagocytosis with WEB 2086 is also counteracted by the treatment with PAF [ 66 , 67 ]. The authors suggest that these data on phagocytosis of yeast cells by hemocytes are related to the activation of PAF receptors and provides a novel insight into the cell signaling pathway of non-self recognition related to cellular immune reactions in the insect-parasite relationship.…”

Section: Trypanosoma Rangeli Infection and Rhodniumentioning

confidence: 99%

“…Finally, Figueiredo et al . [ 66 ] demonstrated that hemocyte phagocytosis was significantly reduced by oral infection with T. rangeli . These authors demonstrated that hemocyte phagocytosis inhibition caused by the parasite infection was rescued by exogenous arachidonic acid or PAF applied by hemocelic injection.…”

Section: Trypanosoma Rangeli Infection and Rhodniumentioning

confidence: 99%

See 1 more Smart Citation

Trypanosoma rangeli: a new perspective for studying the modulation of immune reactions of Rhodnius prolixus

et al. 2009

Self Cite

View full text Add to dashboard Cite

Insects are exposed to a wide range of microorganisms (bacteria, fungi, parasites and viruses) and have interconnected powerful immune reactions. Although insects lack an acquired immune system they have well-developed innate immune defences that allow a general and rapid response to infectious agents.Over the last few decades we have observed a dramatic increase in the knowledge of insect innate immunity, which relies on both humoral and cellular responses. However, innate reactions to natural insect pathogens and insect-transmitted pathogens, such as parasites, still remain poorly understood.In this review, we briefly introduce the general immune system of insects and highlight our current knowledge of these reactions focusing on the interactions of Trypanosoma rangeli with Rhodnius prolixus, an important model for innate immunity investigation.

show abstract

“…In addition, the phagocytosis of yeast cells in vitro has been suggested to be related to the activation of PAF receptors in R. prolixus hemocytes (Figueiredo et al 2008a). Furthermore, Figueiredo et al (2008b) showed that the inhibition of hemocyte phagocytosis caused by T. rangeli infection in vivo is rescued by either exogenous arachidonic acid or PAF applied by hemocelic injection.…”

Section: Resultsmentioning

confidence: 99%

Effects of platelet-activating factor on the interaction of Trypanosoma cruzi with Rhodnius prolixus

et al. 2010

View full text Add to dashboard Cite

We investigated the effects of platelet-activating factor (PAF) on the interaction of Trypanosoma cruzi with Rhodnius prolixus. The parasites (epimastigotes) were treated with PAF and/or WEB 2086 (PAF antagonist) for 1 h prior to the interaction experiments. PAF stimulated both in vivo and ex vivo interactions between T. cruzi and R. prolixus while WEB 2086 abrogated these effects. PAF-treated epimastigotes also showed an increase in surface negativity and in the amount of surface sialic acid. Neither of these effects was observed when the epimastigotes were treated with neuraminidase following PAF treatment. In the ex vivo interaction experiments, the number of epimastigotes bound to the midguts of the insects was reduced when the epimastigotes had been treated with neuraminidase. We conclude that PAF modulates the interaction of T. cruzi with R. prolixus by altering the amount of sialyl residues at the surface of the parasite.

show abstract

Blockades of phospholipase A2 and platelet-activating factor receptors reduce the hemocyte phagocytosis in Rhodnius prolixus: In vitro experiments

Cited by 30 publications

References 47 publications

Eicosanoid Actions in Insect Immunity

Eicosanoid Actions in Insect Immunity

Trypanosoma rangeli: a new perspective for studying the modulation of immune reactions of Rhodnius prolixus

Effects of platelet-activating factor on the interaction of Trypanosoma cruzi with Rhodnius prolixus

Contact Info

Product

Resources

About