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Cell structure, function and adaptation
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
Central to understanding many diseases is the appreciation that an oxygen-rich environment is potentially toxic and that protection against oxidant-induced stress is key to cell survival. The balance between oxidation and reduction is central to many processes including the reduction of ribose acids to generate deoxyribose, which is a critical component of DNA. Antioxidant enzymes are positioned throughout the cell to maximize protection. Superoxide dismutase 2 (SOD2) is located in mitochondria where it quickly takes reactive superoxide anions and converts them to the less potent hydrogen peroxide. This diffuses from mitochondria and can be destroyed by catalase. Within the soluble component of the cytoplasm (the cytosol) many peroxidases and transferases protect against oxidative species or make use of them in other cell reactions. Lipid peroxidation can occur as a chain reaction, as is seen in alcoholic liver disease (see Chapter 11), and there are many antioxidant enzymes associated with microsomes that can abort these reactions. In addition to enzymatic protection, which can also use hydrogen for reducing reactions, there are other molecules associated with reduced nicotinamide adenine dinucleotide (NADH) and reduced nicotinamide adenine dinucleotide phosphate (NADPH) that offer protection, notably the reduced tripeptide glutathione, uric acid, and vitamins E and C.
Mitochondrial Stress and Cellular Senescence
Published in Shamim I. Ahmad, Handbook of Mitochondrial Dysfunction, 2019
Irene L. Tan, Michael C. Velarde
The contribution of mitochondrial ROS to cellular senescence is supported by studies on mitochondrial antioxidants. Mitochondria-specific antioxidant mitoQ [10-(6ʹ-ubiquinonyl) decyltriphenylphosphonium bromide] inhibits telomere shortening and extends lifespan in fibroblasts exposed to mild oxidative stress (Saretzki, Murphy, and von Zglinicki 2003). Deficiency in the mitochondrial antioxidant enzyme superoxide dismutase 2 (SOD2) leads to senescence in mouse and human keratinocytes (Velarde et al. 2015, 2012). SOD2 deficiency hampers mitochondrial complex II activity and causes nuclear DNA damage, consequently leading to cellular senescence (Velarde et al. 2012). However, while SOD2 is important in limiting mitochondrial ROS-mediated senescence, excessive amounts of antioxidant proteins (e.g. SOD2 and catalase) do not necessarily inhibit the senescence phenotype in hyperoxia-induced senescent cells (Klimova et al. 2009), suggesting that endogenous levels of antioxidant proteins is sufficient to limit oxidative stress.
A Potential Natural Product Combination Targeting Memory Disorders
Published in Vikas Kumar, Addepalli Veeranjaneyulu, Herbs for Diabetes and Neurological Disease Management, 2018
Manju Bhaskar, Meena Chintamaneni, Addepalli Veeranjaneyulu
SODs are the main antioxidant enzymes that convert superoxide anions to H2O2, protecting cells and tissues from ROS generated from endogenous and exogenous sources. SODs consist of three types of isoforms expressed in mammalian cells: copper/zinc SOD (CuZn-SOD, SOD1), which is located in the cytoplasm, manganese SOD (Mn-SOD, SOD2), which exists in the mitochondrial matrix, and extracellular SOD (EC-SOD, SOD3).68 SOD is considered to be one of the most vulnerable indicators as an antioxidant enzyme in AD and cognitive dementia. Several studies have shown decreased SOD in the frontal cortex of AD patients. The SOD2 activity has been reported to be reduced in AD brains. The activity of SOD in serum was reduced in both MCI and AD patients compared to controls. The reduction in SOD activity was also reported in hippocampus from MCI patients; however, total levels of SOD were reduced as well.69
Saliva diagnostics: emerging techniques and biomarkers for salivaomics in cancer detection
Published in Expert Review of Molecular Diagnostics, 2022
Jieren Liu, Dongna Huang, Yuanzhe Cai, Zhihua Cao, Zhiyu Liu, Shuo Zhang, Lin Zhao, Xin Wang, Yuchuan Wang, Feijuan Huang, Zhengzhi Wu
Saliva contains proteins that provide information for disease detection. The study of saliva biomarkers can be convenient, quick and non-invasive to improve the diagnosis rate of diseases. The saliva samples can be used for genotyping, amplification or sequencing by nucleic acid detection, and can be stored for a long time without significant degradation [13]. In the detection of saliva samples, we can determine the physiological status of the body by detecting certain proteins in saliva. For example, the study by ISHIKAWA et al. showed that, the expression of a number of proteins such as α-2-macroglobulin-like protein 1, cornulin, hemoglobin subunit β, Igĸ chain V–II region Vĸ 167, kininogen-1 and transmembrane protease serine 11D has high accuracy for differentiating between patients with oral cancer (OC) and healthy controls (HCs). Among them, keratin has been regarded as a proteomic salivary biomarker to differentiate OC and HC patients [14]. SOD2 can be used as a potential salivary biomarker for liver cancer screening [15].
World Trade Center dust induces nasal and neurological tissue injury while propagating reduced olfaction capabilities and increased anxiety behaviors
Published in Inhalation Toxicology, 2022
Michelle Hernandez, Joshua Vaughan, Terry Gordon, Morton Lippmann, Sam Gandy, Lung-Chi Chen
Dysregulation of intracellular calcium homeostasis or aberrant calcium signaling has been implicated in CNS dysfunction, affecting both neuronal and non-neuronal cells (Chakroborty and Stutzmann 2011; Magi et al. 2016). Aspartate Beta-Hydroxylase (Asph) gene involvement in calcium homeostasis has been greatly detailed throughout molecular literature but has not been extensively researched in the exposure sciences (Dinchuk et al. 2000; Yang et al. 2010). Preliminary evidence for calcium dysregulation has been presented with Asph mRNA transcript upregulation (15–20%) 90-days post-exposure in mice (Supplemental Figure 5). Equally, oxidative stress had also been implicated in early AD pathologies, linked to metal homeostatic imbalances (Miranda et al. 2000; Bayer et al. 2006). Despite unremarkable SOD2 mRNA transcripts at 90 days post-WTCPM exposure, SOD2 data are informative in terms of functional pathogenesis with respect to neurological disease manifestations. SOD2 is a major mitochondrial antioxidant defense enzyme involved in free radical detoxification with critical implications regarding calcium homeostasis maintenance in neuronal cells (Zhao et al. 2019).
Diet Supplementation with Pomegranate Peel Improves Embryonic Survival in a Mouse Model of Early Pregnancy Loss
Published in Journal of Dietary Supplements, 2022
Kaïs H. Al-Gubory, Catherine Garrel
Enzyme activities were determined as described previously (Al-Gubory et al. 2014, 2016). Activity of TSOD was measured using the pyrogallol assay based on the competition between pyrogallol oxidation by superoxide anion radical (•O2−), and •O2− dismutation by SOD. Activity of SOD2 was determined by assaying for SOD activity in the presence of sodium cyanide, which selectively inhibits SOD1 but not SOD2. Activity of SOD1 was calculated by subtracting SOD2 activity from TSOD activity. The rate of auto-oxidation is taken from the increase in the absorbance at 420 nm. Activity of GPX was measured using the GR-NADPH method. Activity was determined by a coupled assay system in which oxidation of glutathione (GSH) was coupled to NADPH oxidation catalyzed by GR. The rate of GSH oxidized by tertiary butyl hydroperoxide was evaluated by the decrease of NADPH in the presence of ethylenediaminetetraacetic acid (EDTA), excess GSH and GR. The rate of decrease in concentration of NADPH was recorded at 340 nm. Activity of GR was measured by the standard method of NADPH oxidation. In this assay, GSSG is reduced to GSH by GR, which oxidizes NADPH to NADP+. NADPH consumption was determined at 340 nm.