Reactive oxygen intermediates activate NF-kappa B in a tyrosine kinase- dependent mechanism and in combination with vanadate activate the p56lck and p59fyn tyrosine kinases in human lymphocytes

Abstract

We have previously observed that ionizing radiation induces tyrosine phosphorylation in human B-lymphocyte precursors by stimulation of unidentified tyrosine kinases and this phosphorylation is substantially augmented by vanadate. Ionizing radiation generates reactive oxygen intermediates (ROI). Because H2O2 is a potent ROI generator that readily crosses the plasma membrane, we used H2O2 to examine the effects of ROI on signal transduction. We now provide evidence that the tyrosine kinase inhibitor herbimycin A and the free radical scavenger N- acetyl-cysteine inhibit both radiation-induced and H2O2-induced activation of NF-kappa B, indicating that activation triggered by ROI is dependent on tyrosine kinase activity. H2O2 was found to stimulate Ins-1,4,5-P3 production in a tyrosine kinase-dependent manner and to induce calcium signals that were greatly augmented by vanadate. The synergistic induction of tyrosine phosphorylation by H2O2 plus vanadate included physiologically relevant proteins such as PLC gamma 1. Although treatment of cells with H2O2 alone did not affect the activity of src family kinases, treatment with H2O2 plus vanadate led to activation of the p56lck and p59fyn tyrosine kinases. The combined inhibition of phosphatases and activation of kinases provides a potent mechanism for the synergistic effects of H2O2 plus vanadate. Induction of tyrosine phosphorylation by ROI may thus lead to many of the pleiotropic effects of ROI in lymphoid cells, including downstream activation of PLC gamma 1 and NF-kappa B.

Oxygen Free Radical Signaling in Ischemic Preconditioninga

“…A large number of studies from different laboratories including our own showed the induction of the expression of antioxidant genes during the preconditioning. 24 We recently demonstrated nuclear translocation and activation of NFκB in response to preconditioning. 25 Increased binding of NFκB was found to be dependent on both tyrosine kinase and p38 MAP kinase.…”

Oxidative stress triggers tyrosine phosphorylation in B cells through a redox‐ and inflammatory cytokine‐sensitive mechanism

“…Recent studies demonstrate that exposing B and T cells to oxidants such as hydrogen peroxide (H 2 O 2 ), 7-9 diamide 9,10 and phenylarsine oxide (PAO) [11][12][13] or to g -ray irradiation 14,15 results in an increase in tyrosine phosphorylation and two early biological responses, an elevation in intracellular calcium and increased phosphoinositide turnover PTK inhibitors such as herbimycin A and tyrphostin are reported to prevent tyrosine phosphorylation and the following cellular events caused by H 2 O 2 7 or ionizing irradiation, 14,15 suggesting that these agents induce tyrosine phosphorylation through PTK activation and that the activation may be an early and requisite signal for inducing these cellular events. In fact, several PTKs, such as p56/53 lyn and p72 syk , which are involved in transmembrane signalling triggered via surface immunoglobulin are also activated after the exposure to H 2 O 2 7 or ionizing irradiation.…”

“…In fact, several PTKs, such as p56/53 lyn and p72 syk , which are involved in transmembrane signalling triggered via surface immunoglobulin are also activated after the exposure to H 2 O 2 7 or ionizing irradiation. 14,15 Moreover, phospholipase C-g, a physiologically relevant protein, is tyrosine-phosphorylated after surface immunoglobulin engagement as well as after exposure to g -ray irradiation. 14 These facts suggest that similar cellular events may occur after cross-linking surface immunoglobulin and exposure to oxidative stress.…”

REDD‐1 aggravates endotoxin‐induced inflammationVIAatypical NF‐κB activation

“…For example, the DNA-damaging agent doxorubicin stimulates NF-kB activation in IKKa/b double-knockout cells (7), indicating that NF-kB can be activated without IKKa/b activation. Oxidative stress or H 2 O 2 phosphorylates IkBa at Tyr42, but not at the IKKb-dependent phosphorylation sites of Ser32/36 that are responsible for IkBa degradation (5,31), via certain tyrosine kinases, such as p56-lck, Syk, and c-Src (19,(32)(33)(34). The Tyr42-phosphorylated IkBa may not be degraded and is bound to the SH2 domain of the regulatory PI3K subunit p85, thus unmasking NF-kB and allowing it to translocate to the nucleus (19).…”