Activation of tracheal smooth muscle responsiveness by fMLP-treated HL-60 cells and neutrophils
Munoz, N.M.; Hamann, K.J.; Vita, A.; Cozzi, P.J.; Baranowski, S.; Solway, J.; Leff, A.R.
American Journal of Physiology 264(3 Pt 1): L222-L228
1993
ISSN/ISBN: 0002-9513 PMID: 8460711 Document Number: 414778
We assessed the effects of cultured human promyelocytic leukemia (HL-60) cells and polymorphonuclear leukocytes (neutrophils) isolated from peripheral human blood on tracheal smooth muscle responsiveness in 40 male Hartley guinea pigs. Undifferentiated HL-60 cells (16-25 passages) were activated in vitro by incubation with 1 mu-M f-Met-Leu-Phe (fMLP), and force of contraction was measured isometrically using an in situ preparation of tracheal smooth muscle. Increasing concentrations of acetylcholine (ACh; 10-10 to 10-6 mol/cm-2 tracheal surface) were applied topically to the epithelial surface pretreated with 4 times 10-6 fMLP-activated HL-60 cells, 4 times 10-6 fMLP-activated neutrophils, 4 times 10-6 sham-activated HL-60 cells, fMLP + vehicle, or vehicle control. Topical application of fMLP-activated HL-60 cells caused a maximum active tension (AT) of 1.13 +- 0.2 g/cm after 5 min; fMLP-activated neutrophils, sham-activated HL-60 cells, or fMLP + vehicle had no effect. The fMLP-activated HL-60 cells also caused substantial augmentation of tracheal contraction to ACh (P lt 0.05 vs. sham-activated cells for all concentrations gt 10-9 mol/cm-2). Although fMLP treatment caused 247 +- 28% increase from baseline level in 0-2- cntdot production, neither direct contraction nor augmentation of muscarinic stimulation was demonstrated after topical application of 4 times 10-6 neutrophils. In 12 other preparations, fMLP-activated HL-60 cells were pretreated with either 10 mu-M indomethacin (Indo) or 100 mu-M A63162, a 5-lipoxygenase inhibitor. Pretreatment with Indo caused complete blockade of direct tracheal contraction and 88 +- 13% blockade of muscarinic augmentation; there was no effect after A63162. We find that activated HL-60 cells but not activated neutrophils cause direct contraction of guinea pig tracheal smooth muscle and augmentation of the response caused by exogenous ACh. These effects depend on secretion of bronchoactive cyclooxygenase products caused by pretreatment with fMLP.