Induction of Reactive Oxygen Species

Besides these external processes, formation of ROS may also take place intrac-ellularly. Photooxidative stress, including UVB, stimulates various cellular processes leading to the production of superoxide radicals and hydrogen peroxide, as well as singlet-oxygen and hydroxyl radicals. The sources and production sites of ROS are mainly related to photosynthetic activities such as the pseudocyclic photophosphorylation and the Mehler reaction, which stimulate the accumulation of hydrogen peroxide (Asada 1994 Elstner 1990). 

UV-induced ROS are extremely toxic to cells by causing oxidative damage to all biomolecules (Sies 1991). For instance, lipids, which are major compounds of all biological membranes, may be destroyed by ROS. After a first initiation reaction an unsaturated fatty acid is converted to a peroxyl radical, which in turn attacks another unsaturated fatty acid finally leading to free radical cascades. This photochemical peroxidation of unsaturated fatty acids may be particularly damaging for membrane structure and function (Bischof et al 2006a). 

---

Wedgwood S, Dettman RW, Black SM ET-1 stimulates pulmonary arterial smooth muscle cell proliferation via induction of reactive oxygen species. Am J Physiol Lung Cell Mol Physiol 2001 28LL1058-L1067. 

Bagchi, M. and Stohs, S.J., In vitro induction of reactive oxygen species by 2,3,7,8-tetrachlorodibenzo-p-dioxin, endrin and lindane in rat peritoneal macrophages, and hepatic mitochondria and microsomes. Free RaJica/Bio/. ATeJ., 14,11,1993. 

P. Kama, S. Zughaier, V. Parmu, R. Simmons, S. Narzan, and R. Aneja, Induction of reactive oxygen species -mediated autophagy by a novel microtubule-modulating agent. J. Biol Chem., 285 (2010) 18737-48. 

Rugo, R. E., Secretan, M. B., Schiestl, R. H. (2009). X radiation causes a persistent induction of reactive oxygen species and a delayed reinduction of TP53 in normal human diploid fibroblasts. Radial Res., 158(2), 210-219. 

Chiu TL, Su CC (2010) Tanshinone IIA induces apoptosis in human lung cancer A549 cells through the induction of reactive oxygen species and decreasing the mitochondrial membrane potential. Int J Mol Med 25 231... 

Aerts, A.M., Francois, I.E., Meert, E.M., Li, Q.T., Cammue, B.P., and Thevissen, K. (2007) The antifungal activity of RsAFP2, a plant defensin from raphanus sativus, involves the induction of reactive oxygen species in Candida albicans. JMol Microbiol Biotechnol 13 243-247. 

Woo JH, Kim YH, Choi YJ, Kim DG, Lee KS, Bae JH, Min DS, Chang JS, Jeong YJ, Lee YH, Park JW, Kwon TK. 2003. Molecular mechanisms of curcumin-induced cytotoxicity induction of apoptosis through generation of reactive oxygen species, down-regulation of Bcl-XL and IAP, the release of cytochrome c and inhibition of Akt. Carcinogenesis 24 1199-1208. 

Figure 22.3 Signaling pathways activated by CpG DNA. CpG is thought to enter the cell via a pH-dependent step that may be receptor mediated. There is a possible role for the toll like receptor 9 (TLR-9). Once inside the cell, CpG DNA appears to act, through a number of signal transduction pathways, including the generation of reactive oxygen species (ROSs), the ubiquitination and degradation of IrcB, and activation of the mitogen-activated protein kinase (MAPK) pathways, which ultimately lead to the induction of activating protein 1 (AP-1) and nuclear factor kappa B (NF-kB).

Suzuki K, Hei TK. 1996. Induction of heme oxygenase in mammalian cells by mineral fibers distinctive effect of reactive oxygen species. Carcinogenesis 17(4) 661-667. 

Smith KR, Aust AE (1997) Mobilization of iron from urban particulates leads to generation of reactive oxygen species in vitro and induction of ferritin synthesis in human lung epithehal cells. Chem Res Toxicol 10 828-834... 

---