Investigation into the pro-inflammatory properties of TNF-alpha and heme in leukocytes in vitro and in vivo.

Abstract

During inflammatory responses, neutrophils and other leukocytes adhere to the endothelium, leaving the blood vessels and actively moving towards the inflammatory sites. At present, specific inflammatory mechanisms that operate in the neutrophil adhesive properties have not been completely described. Using a model of neutrophil activation by TNF-±, a potent inflammatory cytokine that induces a significant cell adhesion, we propose to investigate the mechanisms and signaling pathways that mediate this increase in neutrophil adhesion. We will investigate the role of the transcription factor, NFºB, in this mechanism and suggest the hypothesis that cellular proteins called Rho GTPases may be involved in the signaling pathway of these cells after their activation by TNF-±. In parallel with this objective, the effects of simvastatin, a drug class of statins, will be studied, aiming to identify new therapeutic targets for the development of anti-inflammatory agents. Results obtained by our research group suggest that simvastatin can directly inhibit the activation of neutrophils; further studies will be conducted to better understand the effect of this drug on the modulation of the adhesive properties of neutrophils. Accordingly, this study will investigate the signaling pathways involved in the mechanism of neutrophil adhesive under inflammatory conditions. For the development of this work, flow adhesion assays, flow cytometry, assessing the activity of cytoplasmic proteins involved in cytoskeletal changes, ELISA, real time PCR, confocal microscopy and intravital microscopy will be used. We hope that this study will help to better explain the behavior of neutrophils during an established inflammatory process. The knowledge of these signaling pathways may be important for developing therapeutic targets for diseases characterized by vascular inflammation.