Proteomic Analysis of Neutrophil Priming by PAF.

Polymorphonuclear neutrophils are the main cells of the innate immunity inflammatory response. Several factors can activate or stimulate neutrophils, including platelet-activating factor (PAF), a lipid mediator. Some authors consider the activation induced by PAF priming because it triggers limited production of reactive oxygen species (ROS) and it amplifies the response of the cell to a subsequent activator. The stimulation is reversible, which is critical for modulating the inflammatory response. Exacerbated inflammatory responses lead to serious diseases, such as systemic inflammatory response syndrome (SIRS), among others. Characterizing the stimulation of neutrophils during the possible reversion or prevention of an exaggerated inflammatory response is critical for the development of control strategies. In this study, a proteomic approach was used to identify 36 proteins that differ in abundance between quiescent neutrophils and PAFstimulated neutrophils. The identified proteins were associated with increased DNA repair processes, calcium flux, protein transcription, cytoskeleton alterations that facilitate migration and degranulation, and the release of proinflammatory cytokines and proteins that modulate the inflammatory response. Some of the identified proteins have not been previously reported in neutrophils.

Comparison of the neutrophil proteome in trauma patients and normal controls.

Neutrophils have an impressive array of microbicidal weapons, and in the presence of a pathogen, progress from a quiescent state in the bloodstream to a completely activated state. Failure to regulate this activation, for example, when the blood is flooded with cytokines after severe trauma, causes inappropriate neutrophil activation that paradoxically, is associated with tissue and organ damage. Acidic proteomic maps of quiescent human neutrophils were analyzed and compared to those of activated neutrophils from severe trauma patients. The analysis revealed 114 spots whose measured volumes differed between activated and quiescent neutrophils, with 27 upregulated and 87 downregulated in trauma conditions. Among the identified proteins, grancalcin, S100-A9 and CACNB2 reinforce observed correlations between motility and ion flux, ANXA3, SNAP, FGD1 and Zfyve19 are involved in vesicular transport and exocytosis, and GSTP1, HSPA1 HSPA1L, MAOB, UCH-L5, and PPA1 presented evidence that activated neutrophils may have diminished protection against oxidative damage and are prone to apoptosis. These are discussed, along with proteins involved in cytoskeleton reorganization, reactive oxygen species production, and ion flux. Proteins such as Zfyve19, MAOB and albumin- like protein were described for the first time in the neutrophil. In this work we achieved the identification of several proteins potentially involved in inflammatory signaling after trauma, as well as proteins described for the first time in neutrophils.