ROS I

Reactive Oxygen Metabolite

ROMs are of special importance in inflammatory states, hypersensitivity responses, and in the conditions that result in diminished mucosal blood flow.

From: Comprehensive Toxicology, 2010

Related terms:

Nitric Oxide

Antioxidant

Enzyme

Protein

Hydrogen Peroxide

Superoxide

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The regulation of intracellular redox homeostasis in cancer progression and its therapy

Pritam Sadhukhan, Parames C. Sil, in Pathology, 2020

Abstract

Reactive oxygen species (ROS) are a group of chemically reactive species present in every living cell, with a very short half-life, generated in metabolic reactions. Cells possess endogenous machinery to neutralize ROS and inhibit their accumulation. At low to moderate levels these reactive species are essential for cells. However, at higher concentrations it impairs many life processes by affecting cellular biomolecules. Accumulation of intracellular ROS is regarded as one of the primary causes for oncogenic transformation and cancer progression. Therefore recent therapeutic strategies have been developed to target ROS production and its accumulation. The primary therapeutic goals are inhibiting the accumulation of ROS and induction of apoptosis in the transformed cells either by ROS scavenging or ROS inducing, as ROS can stimulate both proliferative and death signals in the cells. In this chapter, the oncogenic role of ROS and different plausible therapeutic strategies are comprehensively summarized.

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The Role of Reactive Oxygen and Nitrogen Species in Skeletal Muscle

Zsolt Radak, Erika Koltai, in Muscle and Exercise Physiology, 2019

14.5 Conclusions

RONS are necessary, product normal, physiological functions. In skeletal muscle, the production of RONS is increased as a result of muscle contraction and up to a certain level, RONS induce the force generation. Further elevation of RONS leads to fatigue. RONS can induce mitochondrial biogenesis, influence the levels of SIRT1 which controls vital metabolic processes, and is involved in hypertrophy of skeletal muscle. Massive elevation of RONS can lead to increased oxidative stress and alteration of lipids, proteins, and DNA. It is suggested that a moderate level of oxidative damage of lipids can be important to membrane remodeling; moderate level of protein modification by RONS could be important control of protein synthesis. Moreover, moderate level of oxidative DNA modification could be important to increased gene expression and cellular signaling. In skeletal muscle the age-associated decline in muscle mass and function is also related to RONS level and inflammation. Regular exercise has a powerful effect on RONS production, antioxidant, and oxidative damage repair systems. Moreover, regular exercise can attenuate the age-associated function deteriorations.

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Role of Autophagy in Cancer Development via Mitochondrial Reactive Oxygen Species

Bo Liu, Gu He, in Autophagy: Cancer, Other Pathologies, Inflammation, Immunity, Infection, and Aging, 2016

ROS-Regulated Other Autophagic Signaling Pathways

ROS can regulate autophagy through transcription factor activity such as NF-κB leading to the induction of autophagy gene expression (Beclin-1 or p62) in cancer cells. In addition, mitogen-activated protein kinases (MAPKs) are downstream effectors of ROS in autophagy induction, as a novel compound was recently found to induce autophagic cell death by stimulating ROS production and activation of ERK and JNK. ROS-induced ATG gene upregulation in skeletal cells requires p38 activation, p38 and p53 also regulate ROS production in turn as positive-feedback responses. One p53-target gene encodes TP53-induced glycolysis and apoptosis regulator (TIGAR), whose inhibition can increase ROS production and enhance ROS-dependent autophagy (Hoshino et al., 2012). The pro-autophagic Ca2+ channel IP(3)R can be affected by ROS to increase the intracellular Ca2+ level, which has been reported to induce autophagy (Raina et al., 2013) (Figure 12.2).

Figure 12.2. ROS-regulated autophagic pathways.

Autophagy can be divided into five steps: induction, nucleation, elongation, docking and fusion, degradation and recycling. ROS may regulate these five steps through activating or inhibiting various signaling pathways and manipulate autophagy as a survival or programmed cell death role.

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Cardiac Metabolism in Health and Disease

Lionel H. Opie, in Cellular and Molecular Pathobiology of Cardiovascular Disease, 2014

Reactive Oxygen Species

Reactive oxygen species (ROS, also called oxygen free radicals) are a side-product of sites on mitochondrial complexes I and III of the electron transmitter chain (see later in text). In excess, ROS contribute to membrane damage by lipid peroxide formation and are part of the signaling sequence leading to apoptosis. Excess ROS are also derived from many complex sources besides damaged myocyte mitochondria, such as from uncoupled nitric oxide synthase in heart and endothelial cells, from xanthine oxidase and stimulation of membrane NADPH oxidase (by angiotensin II, endothelin, cytokines) and from neutrophils.24 Excess ROS are formed particularly during the reperfusion phase of ischemic damage.25

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Fermented Rice Bran Attenuates Oxidative Stress

Dongyeop Kim, Gi Dong Han, in Wheat and Rice in Disease Prevention and Health, 2014

Inhibitory Effects of Fermented Rice Bran Extract and Ferulic Acid on ROS Generation

ROS generation was evaluated in 3T3-L1 adipocytes following induction of oxidative stress by hydrogen peroxide (100 µM) for 12 hours. Treatment with FRB extract or ferulic acid significantly reduced ROS generation to 92.97–94.54% and 103.79–104.69%, respectively. However, there was no significant difference in ROS reduction between ferulic acid and FRB extract at all concentrations (Fig. 36.1).

FIGURE 36.1. Inhibitory effects of ferulic acid and fermented rice bran extract on ROS generation in 3T3-L1 adipocytes treated with hydrogen peroxide. Measurement of cellular redox status with rates of dichlorofluorescein (DCF) oxidation.

Two different concentrations of fermented rice bran extract (FRB) and ferulic acid (FA) were applied: 1FRB (10 μg/mL), 5FRB (50 μg/mL), 1FA (10 μM), and 5FA (50 μM). The results as mean values are shown with SD (n = 3) (∗∗∗P < 0.001). ROS generation was assessed by DCFDA oxidation (carboxy-H2DCFDA). Cells were plated onto 24-well plates at an initial density of 1 × 104 cells per well, followed by induction of differentiation. Cells were washed three times with 0.5 mL of HBSS per well. Following the addition of 20 μM DCFDA (final concentration), DCF fluorescence was followed continuously for 1 hour using a thermostatic plate reading spectrofluorometer (TECAN, infinite M200, Austria) at excitation and emission wavelengths of 495 and 525 nm, respectively. The amounts of cell proteins in each well were measured by bicinchoninic acid reaction, and DCF fluorescence levels were corrected for variations in total protein content between wells.

NIDDM is associated with increased oxidative stress caused by accelerated production or reduced scavenging of ROS. Some studies have indicated that treatment with antioxidants such as cysteine or N-acetylcystein (NAC) protects β cells from ROS-mediated damage.84 Other studies have found evidence that diabetes is associated with an antioxidant/pro-oxidant imbalance. In addition to impaired antioxidant defense, increased production of ROS has also been proposed.131

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Hordeiviruses (Virgaviridae)☆

Zhihao Jiang, ... Dawei Li, in Reference Module in Life Sciences, 2020

ROS bursts

Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) or superoxide anions (O2-) are amongst the earliest cellular responses against pathogen infection. BSMV infection reduces both H2O2 and O2- elevation by ~10 fold in inoculated leaves compared with the empty vector. The γb protein has a major role in reduction of ROS bursts by interacting directly with glycolate oxidase (GOX), which is localized in peroxisomes and is a key constitutive enzyme in the photorespiration pathway. These results demonstrate that γb interacts with GOX to suppress peroxisomal ROS production and facilitate virus infection, and contributes to an understanding of roles played by ROS and plant ROS-producing enzymes during viral infection.

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Cytochrome P450 and Oxidative Stress in the Liver

A.I. Cederbaum, in Liver Pathophysiology, 2017

Nucleic Acids

ROS cleave the phosphodiester bonds holding bases in RNA and DNA together and break the chain structure of RNA and DNA. ROS oxidize the purine and pyrimidine bases and prevent appropriate base pairing. The carbon 8 position of purines is a very sensitive site for oxidation by ROS; formation of 8-hydroxyguanine or 8-hydroxyadenine, 8-hydroxy-deoxyguanine or 8-hydroxy-deoxyadenine are footprints of ROS attack on RNA or DNA, respectively. ROS can cause deaminations, e.g., remove the amino group from adenine or guanine to form hypoxanthine or xanthine, respectively, or remove the amino group from cytosine to form uracil. This alters correct base pairing in DNA. These reactions are major causes of mutations.

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Redox Signaling and the Onset of the Inflammatory Cascade

Jose P. Vazquez-Medina, in Immunity and Inflammation in Health and Disease, 2018

Abstract

Reactive oxygen species (ROS) generation is an intrinsic event that occurs during the onset of the inflammatory cascade. ROS are crucial for host defense and for the redox-dependent activation of proinflammatory mediators such as NF-κB and NLRP3 inflammasomes. Similarly, ROS can also activate antioxidant and anti-inflammatory transcription factors that control the expression of genes necessary for the resolution of inflammation and the prevention of oxidative stress. Dysregulation of ROS production or insufficient ROS scavenging, however, results in the oxidation of biomolecules and the structural modification of proteins triggering signaling cascades that lead to the onset and progression of inflammatory diseases. Peroxiredoxins regulate ROS levels and thus play a central role in redox signaling. Recent evidence suggests that peroxiredoxins can also activate proinflammatory pathways. The current knowledge of the redox signaling events that occur during the onset of inflammation is discussed in this chapter.

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Inflammasomes and Danger Signals in the Immune System

H.-C. Lai, ... M.A. Pettengill, in Reference Module in Biomedical Sciences, 2014

Reactive Oxygen Species

ROS are highly reactive molecules originating from molecular oxygen, and are involved in a broad variety of pathologies and aging. A major pool of ROS is produced during oxidative phosphorylation within mitochondria, where electrons are passed through a series of proteins until they reach their final destination on an oxygen molecule. In phagocytic cells, microbial internalization also leads to the activation of membrane-bound NADPH oxidase, which generates ROS mainly for killing invading microbes. Besides the damaging properties of these oxidant molecules, a growing number of studies have highlighted their importance at lower concentrations as cell signaling molecules mediating their effects in specific cellular subdomains. The multiple roles of ROS in secondary signaling, cross-linking of the cell wall, DNA laddering, protein modification, and cell death, are well established. In addition, a major role of ROS in the activation of an inflammasome has emerged recently.

The molecular mechanisms whereby ROS activate the NLRP3 inflammasome are not fully understood but may involve a thioredoxin-interacting protein (also known as VDuP1), which associates with NLRP3 in a ROS-dependent manner. Furthermore, autophagy, which is an evolutionarily conserved cellular process that promotes the turnover of damaged proteins and organelles, is involved in ROS production. The inhibition of autophagy disturbs mitochondrial integrity, leading to an increase in mitochondrial ROS production and the release of mitochondrial DNA, which is responsible for activation NLRP3-dependent caspase-1 activation. Mitochondrial DNA must in fact be oxidized in order to activate NLRP3.

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Coenzyme Q10 as an Antioxidant in the Elderly

Elena M. Yubero-Serrano, ... Jose Lopez-Miranda, in Aging, 2014

Oxidative Stress and Antioxidant Defense

Reactive oxygen species (ROS) are produced from molecular oxygen as a result of normal cellular metabolism and they have beneficial effects at low concentrations. However, when there is an overproduction of ROS it produces adverse modifications to cell components, such as lipids, proteins and DNA, inhibiting their normal function.1 Organisms have developed a series of defense mechanisms against ROS (Fig. 11.1); the enzymatic antioxidant defenses include superoxide dismutase, catalase and glutathione peroxidase, while the non-enzymatic antioxidants include ascorbic acid, tocopherol, glutathione, coenzyme Q10 (CoQ10) and others. Oxidative stress (OS) is defined as the imbalance between ROS and antioxidant defenses, in favor of ROS. Oxidative stress is a condition associated with chronic degenerative diseases, such as cancer, metabolic disease and cardiovascular diseases, and also the aging process.

FIGURE 11.1. Enzymatic and non-enzymatic antioxidant defenses.

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Chemico-Biological Interactions

Volume 224, 5 December 2014, Pages 164-175

Mini-review

Free radicals, reactive oxygen species, oxidative stress and its classification

Author links open overlay panelVolodymyr I.Lushchak

Outline

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https://doi.org/10.1016/j.cbi.2014.10.016Get rights and content

Highlights

•

Generation and elimination of reactive oxygen species (ROS) are balanced under normal conditions.

•

ROS homeostasis disturbances may be provoked by diverse internal and external factors.

•

Disbalance between ROS generation and elimination in favor of the former may result in oxidative stress.

•

Classification of oxidative stress may based on its intensity is proposed.

Abstract

Reactive oxygen species (ROS) initially considered as only damaging agents in living organisms further were found to play positive roles also. This paper describes ROS homeostasis, principles of their investigation and technical approaches to investigate ROS-related processes. Especial attention is paid to complications related to experimental documentation of these processes, their diversity, spatiotemporal distribution, relationships with physiological state of the organisms. Imbalance between ROS generation and elimination in favor of the first with certain consequences for cell physiology has been called "oxidative stress". Although almost 30 years passed since the first definition of oxidative stress was introduced by Helmut Sies, to date we have no accepted classification of oxidative stress. In order to fill up this gape here classification of oxidative stress based on its intensity is proposed. Due to that oxidative stress may be classified as basal oxidative stress (BOS), low intensity oxidative stress (LOS), intermediate intensity oxidative stress (IOS), and high intensity oxidative stress (HOS). Another classification of potential interest may differentiate three categories such as mild oxidative stress (MOS), temperate oxidative stress (TOS), and finally severe (strong) oxidative stress (SOS). Perspective directions of investigations in the field include development of sophisticated classification of oxidative stresses, accurate identification of cellular ROS targets and their arranged responses to ROS influence, real in situ functions and operation of so-called "antioxidants", intracellular spatiotemporal distribution and effects of ROS, deciphering of molecular mechanisms responsible for cellular response to ROS attacks, and ROS involvement in realization of normal cellular functions in cellular homeostasis.

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Abbreviations

BOS

basal oxidative stress

ETC

electron transport chain

HOS

high intensity oxidative stress

8-OHG

8-hydroxyguanine

G6PDH

glucose-6-phosphate dehydrogenase

GPx

glutathione-dependent peroxidase

glutathione reductase

GSH

glutathione reduced

GSNO

S-nitrosoglutathione

GSSG

glutathione oxidized

IDH

NADP+-isocitrate dehydrogenase

IOS

intermediate intensity oxidative stress

LOOH

lipid peroxides

LOS

low intensity oxidative stress

MDA

malonic dialdehyde

NADP-ME

NADP-malic enzyme

NOE

no observable effect point

nitric oxide radical

6PGDH

6-phosphogluconate dehydrogenase

8-oxodG

8-oxo-7,8-dihydro-2′-deoxyguanosine

8-oxoGua

8-oxo-7,8-dihydroguanine

PPP

pentose phosphate pathway

RNS

reactive nitrogen species

ROS

reactive oxygen species

reactive species

O2−

superoxide anion radical

SOD

superoxide dismutase

TBA

thiobarbituric acid

TBARS

thiobarbituric acid reactive substances

TRR

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