Effect of microtubule-disrupting agents on superoxide production in human polymorphonuclear leukocytes

Abstract

We explored the effects of compounds known or proposed to affect microtubule functions on superoxide (O 2 −) production in human polymorphonuclear leukocytes stimulated by N-formyl-methionyl-phenylalanine (f-Met-Phe), calcium ionophore A23187 and phorbol myristate acetate. F-Met-Phe-induced O 2 − production was markedly potentiated not only by microtubule-disrupting agents, including colchicine, vincristine, vinblastine, nocodazole, podophyllotoxin and griseofulvin, but also deuterium oxide ( 2H 2O), which is proposed to stabilize microtubules, and not affected by lumicolchicine. Ionophore A23187-induced O 2 − production was not influenced by colchicine, and markedly enhanced by 2H 2O, whereas phorbol myristate acetate-induced O 2 − production was not influenced by colchicine, and slightly inhibited by 2H 2O. 2H 2O did not counteract the effects of colchicine and vice versa. Dibutyryl cyclic AMP and prostaglandin E 1 inhibited O 2 − production stimulated by f-Met-Phe and ionophore A23187, whereas phorbol myristate acetate-induced O 2 − production was strongly resistant to the inhibitory effect of these agents. The enhancing effect of colchicine and 2H 2O on f-Met-Phe-induced O 2 − production was abolished by dibutyryl cyclic AMP. Colchicine promoted concanavalin A cap formation, and 2H 2O produced cancanavalin A patch formation, whereas dibutyryl cyclic AMP did not affect the distribution of concanavalin A receptors. In addition, 2H 2O and dibutyryl cyclic AMP did not interfere with the colchicine-induced concanavalin A cap formation. These findings suggest that f-Met-Phe, ionophore A23187 and phorbol myristate acetate may activate the oxidative metabolism of human polymorphonuclear leukocytes through different mechanisms, and that microtubule-disrupting agents, 2H 2O and cyclic AMP agonists may affect the different steps of the activating system of NAD(P)H oxidase.