A ROLE FOR ENDOGENOUS MONO-HYDROXY-EICOSATETRAENOIC ACIDS (HETES) IN THE REGULATION OF HUMAN NEUTROPHIL MIGRATION

Abstract

The possibility that endogenous monohydroxy-eicosatetraenoic acids (HETE) derived from the lipoxygenation of arachidonic acid might serve a role in human neutrophil migration was examined by studying the effects of depletion of the intracellular HETE on random migration and chemotaxis. The intracellular contents of approximately 2000 ng of 11-HETE and 500 ng of 5-HETE/108 neutrophils are distributed preferentially in the cellular membranes and are increased by specific chemotactic factors. The depletion of intracellular HETE that resulted from pre-incubating, washing and resuspending neutrophils in 3-20 .mu.M, 5,8,11,14-eicosatetraynoic acid (TYA), an inhibitor of lipoxygenase and cyclooxygenase activity, or in 5-10 .mu.M nordihydroguaiaretic acid (NDGA), a selective inhibitor of lipoxygenase activity, was associated with suppression of neutrophil random migration and chemotaxis to several stimuli without evidence of cytotoxicity. Maximal suppression of migration was achieved by a 30-60 min preincubation with the inhibitors, a time-course analogous to that required for optimal depletion of the endogenous HETE. Inhibitors of cyclooxygenase activity enhanced random migration and, to a lesser extent, chemotaxis. The inhibition of migration achieved by pre-incubating and maintaining the neutrophils in TYA or NDGA was fully reversed by washing and resuspending the neutrophils in buffer or by the addition of purified neutrophil 5-HETE in quantities as small as 20 ng/2 .times. 106 neutrophils for random migration and 0.8 ng/2 .times. 106 neutrophils for chemotaxis; the addition of 11-HETE was less effective. The relationship of the intracellular concentrations of endogenous HETE to neutrophil migration is consistent with a potential role of the HETE as cellular mediators.