Acrolein is a toxic, highly reactive alpha,beta-unsaturated
aldehyde that is present in high concentrations in cigarette
smoke. In the current study, the effect of
acrolein on
eicosanoid synthesis in stimulated human neutrophils was examined.
Eicosanoid synthesis in neutrophils was initiated by priming with
granulocyte-macrophage colony-stimulating factor (
GM-CSF) and subsequent stimulation with formyl-
methionyl-leucyl-phenylalanine (fMLP) and
5-lipoxygenase (5-LO) products in addition to small amounts of
cyclooxygenase (COX) products were detected using LC/MS/MS. A dose-dependent decrease in the formation of 5-LO products was observed in
GM-CSF/fMLP-stimulated neutrophils when
acrolein (0-50 microM) was present with almost complete inhibition at > or = 25 microM
acrolein. The production of COX products was not affected by
acrolein in these cells. The effect of
acrolein was examined on key parts of the
eicosanoid pathway, such as
arachidonic acid release, intracellular
calcium ion concentration, and
adenosine production. In addition, the direct effect of
acrolein on 5-LO enzymatic activity was probed using a recombinant
enzyme. Some of these factors were affected by
acrolein but did not completely explain the almost complete inhibition of 5-LO product formation in
GM-CSF/fMLP-treated cells with
acrolein. In addition, the effect of
acrolein on different stimuli that initiate the 5-LO pathway [
platelet-activating factor (PAF)/fMLP,
GM-CSF/PAF, opsonized
zymosan, and
A23187] was examined.
Acrolein had no significant effect on the
leukotriene production in neutrophils stimulated with PAF/fMLP,
GM-CSF/ PAF, or OPZ. Additionally, 50% inhibition of the 5-LO pathway was observed in A23187-stimulated neutrophils. Our results suggest that
acrolein has a profound effect on the 5-LO pathway in neutrophils, which may have implications in disease states, such as
chronic obstructive pulmonary disease and other
pulmonary disease, where both activated neutrophils and
acrolein are present.