Release of Mitochondrial Apoptogenic Factors and Cell Death are Mediated by CK2 and NADPH Oxidase

Abstract

Activation of the NADPH oxidase subunit, NOX2, and increased oxidative stress are associated with neuronal death after cerebral ischemia and reperfusion. Inhibition of NOX2 by casein kinase 2 (CK2) leads to neuronal survival, but the mechanism is unknown. In this study, we show that in copper/ zinc-superoxide dismutase transgenic (SOD1 Tg) mice, degradation of CK2a and CK2a 0 and dephosphorylation of CK2b against oxidative stress were markedly reduced compared with wildtype (WT) mice that underwent middle cerebral artery occlusion. Inhibition of CK2 pharmacologically or by ischemic reperfusion facilitated accumulation of poly(ADP-ribose) polymers, the translocation of apoptosis-inducing factor (AIF), and cytochrome c release from mitochondria after ischemic injury. The eventual enhancement of CK2 inhibition under ischemic injury strongly increased 8-hydroxy-2 0 -deoxyguanosine and phosphorylation of H2A.X. Furthermore, CK2 inhibition by tetrabromocinnamic acid (TBCA) in SOD1 Tg and gp91 knockout (KO) mice after ischemia reperfusion induced less release of AIF and cytochrome c than in TBCA-treated WT mice. Inhibition of CK2 in gp91 KO mice subjected to ischemia reperfusion did not increase brain infarction compared with TBCA-treated WT mice. These results strongly suggest that NOX2 activation releases reactive oxygen species after CK2 inhibition, triggering release of apoptogenic factors from mitochondria and inducing DNA damage after ischemic brain injury.

NADPH Oxidase-2: Linking Glucose, Acidosis, and Excitotoxicity in Stroke

“…Recent work showed that neuronal CK2 protein expression and kinase activity are significantly reduced in the ischemic cortex (90). Moreover, pharmacological or siRNA-mediated suppression of CK2 activity exacerbates neuronal death in both cell culture and animal models of brain ischemia (89,90). Decreased levels of CK2 correlated with increased NOX assembly and NOXdependent superoxide production.…”

“…Ischemiareperfusion increases the NOX2 activity in the brain, and both inhibitors of NOX2 activity and genetic downregulation or deficiency of NOX2 components reduce oxidative stress and infarct size in focal cerebral ischemia (81,89,90,178,186). These manipulations likewise reduce oxidative stress and neuronal death after transient forebrain ischemia (77,172,193,195 phox -/ -neurons, which cannot assemble a functional NOX2 complex, were transfected at low efficiency with GFP-labeled p47 phox (green) to reconstitute the NOX2 activity in a small fraction of cultured neurons.…”

Method parameters’ impact on mortality and variability in mouse stroke experiments: a meta-analysis

“…The Infarct size coefficient of variation (in the total 500 control groups9101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110…”

Malondialdehyde and SOD-induced changes of gastric tissues in acute gastric mucosal injury under positive acceleration

“…Neutrophils are the most active inflammation cells in vivo, and would be largely generated in such pathological environments as infection and ischemia, many studies have found that the neutrophil infiltration played an important role in gastric mucosal injury (Ichikawa et al, 2002;Jiménez et al, 2004;Sener et al, 2004). In the early stages of inflammation, neutrophils migration to the inflammation sites play an important defensive role (Cassatella, 1999), but when the ratio of neutrophils and the target cells achieves the non-physiological level (greater than 20:1), it can result in the gastric epithelial cell injuries, and the mechanism might be through activation of the non-active coenzyme II (reduced nicotinamide-adenine dinucleotide phosphate II, NADPH II) inside the cell membrane, thus inducing the neutrophil respiratory burst, releasing large amounts of oxygen free radicals, and resulting in damage of normal tissue (Kim et al, 2012). In this experiment, it was observed that the pathological section of gastric mucosa exhibited a large amount of inflammatory cell infiltration after +Gz exposure, indicating that +Gz exposure could induce the gastric mucosal injury, which might be related with the inflammatory chemotaxis cell-promoted lipid peroxidation.…”