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Oxidative stress

About: Oxidative stress is a research topic. Over the lifetime, 86513 publications have been published within this topic receiving 3845790 citations. The topic is also known as: oxydative stress.


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Journal ArticleDOI
TL;DR: Remarkably, these two gene subsets separate antioxidant scavenging enzymes from the metabolic pathways regenerating the main cellular reducing power, glutathione and NADPH, and may explain, at least in part, the dissociated function of Yap1 and Skn7 in H2O2 and cadmium resistance.

566 citations

Journal ArticleDOI
TL;DR: The present review describes some of the redox-sensitive signaling pathways that are involved in the functional and structural vascular changes associated with hypertension.
Abstract: Diseases such as hypertension, atherosclerosis and diabetes are associated with vascular functional and structural changes including endothelial dysfunction, altered contractility and vascular remodeling. Cellular events underlying these processes involve changes in vascular smooth muscle cell (VSMC) growth, apoptosis/anoikis, cell migration, inflammation, and fibrosis. Many stimuli influence cellular changes, including mechanical forces, such as shear stress, and vasoactive agents, of which angiotensin II (Ang II) appears to be amongst the most important. Ang II mediates many of its pleiotropic vascular effects through NAD(P)H oxidase-derived reactive oxygen species (ROS). Mechanical forces, comprising both unidirectional laminar and oscillatory shear, are increasingly being recognized as important inducers of vascular NO and ROS generation. In general, laminar flow is associated with upregulation of eNOS and NO production and increased expression of antioxidants glutathione peroxidase and superoxide dismutase, thereby promoting a healthy vascular wall and protecting against oxidative vascular injury. On the other hand, oscillatory shear is linked to increased ROS production with consequent oxidative damage, as occurs in hypertension. ROS function as important intracellular and intercellular second messengers to modulate many downstream signaling molecules, such as protein tyrosine phosphatases, protein tyrosine kinases, transcription factors, mitogen-activated protein kinases, and ion channels. Induction of these signaling cascades leads to VSMC growth and migration, expression of pro-inflammatory mediators, and modification of extracellular matrix. In addition, ROS increase intracellular free Ca(2+) concentration, a major determinant of vascular reactivity. ROS influence signaling molecules by altering the intracellular redox state and by oxidative modification of proteins. In physiological conditions, low concentrations of intracellular ROS play an important role in normal redox signaling involved in maintaining vascular function and integrity. Under pathological conditions ROS contribute to vascular dysfunction and remodeling through oxidative damage. The present review describes some of the redox-sensitive signaling pathways that are involved in the functional and structural vascular changes associated with hypertension.

565 citations

Journal ArticleDOI
TL;DR: Results indicate that similar to the situation in the lens, AR is also the major contributor to hyperglycemia-induced oxidative stress in the nerve, although increased flux of glucose through the polyol pathway leads to diabetic lesions in both the lenses and nerve, the mechanisms may be different.
Abstract: Diabetes causes increased oxidative stress, which is thought to play an important role in the pathogenesis of various diabetic complications. However, the source of the hyperglycemia-induced oxidative stress is not clear. It was found that the polyol pathway is the major contributor to oxidative stress in the lenses and nerves of diabetic mice. The first enzyme in the pathway, aldose reductase (AR), reduces glucose to sorbitol, which is then converted to fructose by sorbitol dehydrogenase (SDH). Transgenic mice that overexpress AR specifically in their lenses showed a significant increase in oxidative stress when they became hyperglycemic, as indicated by a decrease in GSH and an increase in malondialdehyde in their lenses. Introducing an SDH-deficient mutation into these transgenic mice significantly normalized the GSH and malondialdehyde levels. These results indicate that both enzymes of the polyol pathway contributed to hyperglycemia-induced oxidative stress in the lens. In the wild-type mice, diabetes caused a significant decrease in GSH in their sciatic nerves, indicative of oxidative stress. In the AR null mutant mice, diabetes did not lead to any decrease in the nerve GSH level. These results indicate that similar to the situation in the lens, AR is also the major contributor to hyperglycemia-induced oxidative stress in the nerve. Although increased flux of glucose through the polyol pathway leads to diabetic lesions in both the lenses and nerve, the mechanisms may be different. AR-induced osmotic stress seems to be the cause of diabetic cataract, whereas AR-induced oxidative stress is probably the cause of neuronal dysfunction.

563 citations

Journal ArticleDOI
TL;DR: The major beneficial effects of treatment with ursodeoxycholic acid are protection against cytotoxicity due to more toxic BAs; the stimulation of hepatobiliary secretion; antioxidant activity, due in part to an enhancement in glutathione levels; and the inhibition of liver cell apoptosis.
Abstract: Several studies have characterized the cellular and molecular mechanisms of hepatocyte injury caused by the retention of hydrophobic bile acids (BAs) in cholestatic diseases. BAs may disrupt cell membranes through their detergent action on lipid components and can promote the generation of reactive oxygen species that, in turn, oxidatively modify lipids, proteins, and nucleic acids, and eventually cause hepatocyte necrosis and apoptosis. Several pathways are involved in triggering hepatocyte apoptosis. Toxic BAs can activate hepatocyte death receptors directly and induce oxidative damage, thereby causing mitochondrial dysfunction, and induce endoplasmic reticulum stress. When these compounds are taken up and accumulate inside biliary cells, they can also cause apoptosis. Regarding extrahepatic tissues, the accumulation of BAs in the systemic circulation may contribute to endothelial injury in the kidney and lungs. In gastrointestinal cells, BAs may behave as cancer promoters through an indirect mechanism involving oxidative stress and DNA damage, as well as acting as selection agents for apoptosis-resistant cells. The accumulation of BAs may have also deleterious effects on placental and fetal cells. However, other BAs, such as ursodeoxycholic acid, have been shown to modulate BA-induced injury in hepatocytes. The major beneficial effects of treatment with ursodeoxycholic acid are protection against cytotoxicity due to more toxic BAs; the stimulation of hepatobiliary secretion; antioxidant activity, due in part to an enhancement in glutathione levels; and the inhibition of liver cell apoptosis. Other natural BAs or their derivatives, such as cholyl-N-methylglycine or cholylsarcosine, have also aroused pharmacological interest owing to their protective properties.

562 citations

Journal ArticleDOI
TL;DR: Oxidative activation offers a novel route for the involvement of TGF beta in tissue processes in which ROS are implicated and endows LTGF beta with the ability to act as a sensor of oxidative stress and to function as a signal for orchestrating the response of multiple cell types.
Abstract: Transforming growth factor beta 1 (TGF beta) is a multifunctional cytokine that orchestrates response to injury via ubiquitous cell surface receptors. The biological activity of TGF beta is restrained by its secretion as a latent complex (LTGF beta) such that activation determines the extent of TGF beta activity during physiological and pathological events. TGF beta action has been implicated in a variety of reactive oxygen-mediated tissue processes, particularly inflammation, and in pathologies such as reperfusion injury, rheumatoid arthritis, and atherosclerosis. It was recently shown to be rapidly activated after in vivo radiation exposure, which also generates reactive oxygen species (ROS). In the present studies, the potential for redox-mediated LTGF beta activation was investigated using a cell-free system in which ROS were generated in solution by ionizing radiation or metal ion-catalyzed ascorbate reaction. Irradiation (100 Gray) of recombinant human LTGF beta in solution induced 26% activation compared with that elicited by standard thermal activation. Metal-catalyzed ascorbate oxidation elicited extremely efficient recombinant LTGF beta activation that matched or exceeded thermal activation. The efficiency of ascorbate activation depended on ascorbate concentrations and the presence of transition metal ions. We postulate that oxidation of specific amino acids in the latency-conferring peptide leads to a conformation change in the latent complex that allows release of TGF beta. Oxidative activation offers a novel route for the involvement of TGF beta in tissue processes in which ROS are implicated and endows LTGF beta with the ability to act as a sensor of oxidative stress and, by releasing TGF beta, to function as a signal for orchestrating the response of multiple cell types. LTGF beta redox sensitivity is presumably directed toward recovery of homeostasis; however, oxidation may also be a mechanism of LTGF beta activation that can be deleterious during disease mechanisms involving chronic ROS production.

562 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20242
20238,839
202217,614
20216,457
20206,203
20195,669