Activation of phospholipase D by interleukin-8 in human neutrophils

Abstract

Interleukin 8 (IL-8), a member of the C-X-C branch of the chemokine superfamily, stimulated the breakdown of 1-O-[3H]alkyl-2-acyl-sn- glycero-3-phosphocholine ([3H]EAPC) and the formation of 1-O-[3H]alkyl- 2-acyl-phosphatidic acid ([3H]-EAPA) in human polymorphonuclear leukocytes (PMN) in the presence of cytochalasin B. In addition, the mass of diradyl-PA was increased with similar kinetics. In the presence of ethanol, 1-O-[3H]alkyl-2-acyl-phosphatidylethanol ([3H]EAPEt) was formed at the expense of [3H]EAPA formation, indicating the activation of phospholipase D by the cytokine. The effect was time- and concentration-dependent, reaching a plateau at 30 seconds with the maximally activating concentration of 120 nmol/L IL-8. Preincubation of cells with 1 microgram/mL Bordetella pertussis toxin inhibited the breakdown of [3H]EAPC and [3H]EAPA formation, indicating a role for a pertussis toxin-sensitive guanosine triphosphate-binding protein. Formation of phosphatidic acid (PA) correlated with activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, the oxidative burst enzyme, with both events occurring in the same concentration range. Inhibition of PA formation, by the presence of ethanol, also inhibited the oxidative burst stimulation by IL-8. Pretreatment of PMN with 10 nmol/L platelet-activating factor potentiated both [3H]EAPA accumulation and activation of NADPD oxidase by IL-8. Collectively, these data show that IL-8 stimulates the metabolism of choline-containing phosphoglycerides in human PMN and support a role for PA in the signaling mechanisms used by IL-8 to stimulate PMN function.

Trp-Lys-Tyr-Met-Val-D-Met stimulates superoxide generation and killing of Staphylococcus aureus via phospholipase D activation in human monocytes

“…PLD has been implicated in a broad range of cellular functions, including cytoskeletal rearrangement, vesicle trafficking, and mitogenesis. PA formation is involved in the regulation of immune responses of phagocytic leukocytes, e.g., phagocytosis, and in the activation of a respiratory burst system in neutrophils [11][12][13][14]. In this study, we show that the peptide stimulates PLD activation, superoxide generation, and bactericidal activity as a downstream event of the binding to the peptide receptor on monocytes.…”

Molecular Cloning of a Novel T Cell-directed CC Chemokine Expressed in Thymus by Signal Sequence Trap Using Epstein-Barr Virus Vector

“…We, however, have not detected any Ca 2ϩ mobilization in response to TARC in T cells including Hut78 and Hut102 so far. The sensitivity of the assay may be too low to detect elevation of cytosolic calcium in restricted areas proximal to activated TARC receptors, or TARC-induced signal transduction may be independent of Ca 2ϩ mobilization as suggested for some other chemokines (46,47).…”

Activation effects of a prion protein fragment [PrP-(106-126)] on human leucocytes

“…Lymphocytes, monocytes and neutrophils from peripheral blood of healthy donors were obtained to greater than 95 % purity by dextran sedimentation and Ficoll separation [23]. Cells were kept in RPMI 1640 medium with 10 % fetal bovine serum (FBS) before experiments.…”