Related Experiment Videos
Priming of the neutrophil respiratory burst is species-dependent and involves MAP kinase activation
1Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Mass., USA.
Background:
Priming of the neutrophil respiratory burst has been implicated in the pathogenesis of multi-system organ failure (MSOF) after sepsis and trauma. The intracellular signal transduction pathways that mediate priming are unclear.
Methods:
Human, porcine, rabbit, rat, and mouse neutrophils were assayed by luminol-dependent chemiluminescence in whole blood and purified neutrophil preparations. Multiple priming agents and agonists were studied, as was inhibition of priming by the p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 and the Mek 1/2 inhibitor PD98059.
Results:
Priming by tumor necrosis factor alpha (TNF-alpha), interleukin-8 (IL-8), and granulocyte-macrophage colony-stimulating factor (GM-CSF) was significantly inhibited by SB203580, whereas platelet-activating factor (PAF) priming was unaffected. Neither TNF-alpha nor PAF primed polymorphonuclear neutrophils (PMNs) within whole blood for N-formyl-methionyl-leucyl-phenylalanine (f-MLP) activation, in contrast to activation by complement-opsonized zymosan (OPZ) or low-dose phorbolmyristate acetate (PMA). Both TNF-alpha and PAF, however, primed purified neutrophils for f-MLP activation. In contrast to human and porcine PMNs, rabbit, rat, and mouse PMNs could not be primed by TNF-alpha or PAF, regardless of the final agonist.
Conclusions:
Priming of the PMN respiratory burst proceeds through multiple signaling pathways, depending on the particular priming agent and agonist pair. Differences in priming between PMNs in whole blood and purified preparations may be physiologically significant. There is a pronounced species dependency in the ability to prime the neutrophil respiratory burst.
Insights
Neutrophil respiratory burst priming involves multiple pathways, varying by agent and species. Differences between whole blood and purified cells may impact physiology, highlighting species-specific responses in neutrophil activation.
Area of Science:
- Immunology
- Cellular Signaling
- Pathophysiology
Background:
- Neutrophil respiratory burst priming is linked to multi-system organ failure (MSOF) post-sepsis and trauma.
- Intracellular signal transduction pathways mediating neutrophil priming remain largely undefined.
Purpose of the Study:
- To investigate the intracellular signaling pathways involved in neutrophil respiratory burst priming.
- To determine the role of p38 MAPK and Mek1/2 in mediating neutrophil priming by various agents.
Main Methods:
- Human, porcine, rabbit, rat, and mouse neutrophils were analyzed using luminol-dependent chemiluminescence.
- Assays were conducted in both whole blood and purified neutrophil preparations.
- The effects of specific priming agents (TNF-alpha, IL-8, GM-CSF, PAF) and agonists (f-MLP, OPZ, PMA) were examined, along with inhibition by p38 MAPK inhibitor (SB203580) and Mek1/2 inhibitor (PD98059).
Main Results:
- SB203580 significantly inhibited priming by TNF-alpha, IL-8, and GM-CSF, but not PAF.
- Priming of neutrophils in whole blood differed from purified preparations, particularly with TNF-alpha and PAF.
- Rabbit, rat, and mouse neutrophils exhibited species-specific resistance to TNF-alpha and PAF priming compared to human and porcine neutrophils.
Conclusions:
- Neutrophil respiratory burst priming utilizes diverse signaling pathways contingent on the priming agent and agonist.
- Discrepancies in priming observed between whole blood and purified neutrophils may hold physiological significance.
- Significant species-dependent variations exist in the capacity to prime the neutrophil respiratory burst.