However, in the latter model systems it is not clear whether leakage over the lysosomal membrane is due to ROS-mediated membrane damage.
In contrast to radiation-induced apoptosis of NPCs, which is mediated by p53, endothelial cell apoptosis is mediated by membrane damage through the second messenger ceramide generated from membrane sphingomyelin following activation of acid sphingomyelinase (ASMase).
As Aβ is generated in the extracellular space, or more likely within the lumen of endocytic vesicles (Koo & Squazzo, 1994; Refolo et al., 1995), its toxic effects may be mediated by membrane damage or by interactions with membrane-bound proteins.
The beneficial effect of argan oil can be mediated by prevention of membrane damage, as it significantly reduced lipid peroxidation, an effect that can be attributed to some components (vegetable oils, tocopherols, ascorbic acid) acting as neutralizers of lipid peroxyl radicals (Sies and Stahl 1995).
Lipid oxidation of rat blood erythrocyte membrane mediated by H2O2 induces membrane damage and subsequently hemolysis occurs.
Hla (α-haemolysin), a pore-forming toxin secreted by S. aureus, is required for the recruitment of LC3, suggesting the recruitment of autophagy components to membrane damage mediated by Hla (Mestre et al., 2010).
Cellular membrane damage is mediated by oxidative attack, which promotes phospholipid degradation and the loss of membrane organization (Pukacka and Ratajczak 2007).
Since HGF counteracted NOS inhibition and marcaine-induced membrane damage, data suggest that NO may mediate early steps in activation and precede HGF-mediated events.
In centrilobular hepatocytes of the liver, cytochrome P450 enzymes mediate metabolism of CCl4 into toxic free radicals which cause lipid peroxidation and membrane damage, eventually resulting in necrosis [ 18].
In plant cells, ROS can directly cause strengthening of host cell walls via cross-linking of glycoproteins, or lipid peroxidation and membrane damage; however, it is also evident that ROS are important signals mediating defense gene activation (Torres and Dangl 2005).
