Pharmacological comparison of LTB₄‐induced NADPH oxidase activation in adherent and non‐adherent guinea‐pig eosinophils

Abstract

1 Leukotriene B 4 (LTB 4 ) stimulation of guinea-pig peritoneal eosinophils, induced a biphasic activation of the NADPH oxidase composed of a rapid (53 min) phase mediated by non-adherent cells and a sustained (3 ± 120 min) phase mediated by CD11b/CD18 adherent eosinophils. Studies were undertaken to compare the intracellular mechanism that mediate these responses. 2 SB 203580 and PP1, inhibitors of p38 mitogen-activated protein (MAP) kinase and the src-family protein tyrosine kinases, respectively caused concentration-dependent attenuation of both the rapid (SB203580: pD 2 =76.31; PP1: pD 2 =75.50) and sustained (SB203580: pD 2 =76.50; PP1: pD 2 =75.73) phases. Similarly, the MAP kinase kinase-1 inhibitor, PD098059 produced partial inhibition of the both phases of superoxide generation. 3 The protein kinase C (PKC) inhibitors Ro-31 8220, GF 109203X and GoÈ 6976 attenuated the rapid NADPH oxidase response (pD 2 s=76.10, 76.72, 76.15 respectively) and, to a lesser extent, (pD 2 s=75.54, 76.02, 76.51 respectively) the sustained phase. 4 An inhibitor of phosphatidylinositol 3-kinase (PtdIns 3-kinase), wortmannin caused concentration dependent attenuation of the sustained (pD 2 =78.68) but not rapid phase of superoxide generation. In contrast, the syk kinase inhibitor, piceatannol abolished the rapid (pD 2 =76.43) but not sustained respiratory responses. 5 This study demonstrates that LTB 4 -induced superoxide generation from adherent and nonadherent eosinophils is mediated via both common (p38 MAP kinase, MEK-1, PKC and the src kinases) and divergent intracellular pathways (syk kinases and PtdIns 3-kinase). This suggests the possibility of therapeutic intervention to selective attenuate activation of adherent tissue eosinophils.

c-Src Induces Phosphorylation and Translocation of p47phox

“…19,35 However, our data together with those reported by others in osteoclasts, leukocytes, eosinophils, and macrophages clearly demonstrate that c-Src is upstream of NAD(P)H oxidase. 25,26,36 This may be explained by the feed-forward mechanism whereby low levels of H 2 O 2 activate c-Src, which in turn initiates a signaling cascade leading to NAD(P)H oxidase activation, generation of ROS, and additional c-Src activation. 19 Mechanisms underlying c-Src regulation of NAD(P)H oxidase remain obscure.…”

“…17,36,43 Because c-Src is important in growth signaling, we questioned whether c-Src could also influence NAD(P)H oxidase by modulating availability of membrane and cytosolic subunits. Long-term Ang II stimulation significantly increased content of NAD(P)H oxidase subunits.…”

Mustard Oil in “Shibori Daikon” a Variety of Japanese Radish, Selectively Inhibits the Proliferation of H-ras-Transformed 3Y1 Cells

“…4) Overactivation of NADPH oxidase and resulting ROS production play important roles in the abnormal growth of ras-transformed cells. [4][5][6][7] On the other hand, ras transformation The effects of 1.6 mg/ml of SMO on the intracellular GSH level after 0, 0.5, 1, 2, 3, 4, and 6 h are shown (A). Amelioration of the growth inhibitory effect of 1.6 mg/ml of SMO by GEE (3 mM) is apparent (B).…”

“…2,3) Recent data attribute this abnormal proliferation of cells by activating ras mutation to the overactivation of NADPH oxidase and resulting ROS production. [4][5][6][7] The HR-3Y1-2 cell line established by Kimura et al was derived from 3Y1 rat fibroblasts transformed with the v-H-ras oncogene. 8) Anchorageindependent proliferation and changed cellular morphology are known features of 3Y1 cells transformed with v-H-ras, 9) and our preliminary study has shown that HR-3Y1-2 cells were capable of proliferating faster than the parent 3Y1cell line.…”

Leukotrienes enhance the bactericidal activity of alveolar macrophages against Klebsiella pneumoniae through the activation of NADPH oxidase

“…35,36,44 Therefore, we evaluated the ability of LTs to modulate NADPHox activation during bacterial infection of the AM. In these experiments, we used the potent and specific NADPHox inhibitor DPI.…”