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1.
Improving oxidative stress resilience in plants.
Kerchev, PI, Van Breusegem, F
The Plant journal : for cell and molecular biology. 2022;(2):359-372
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Abstract
Originally conceived as harmful metabolic byproducts, reactive oxygen species (ROS) are now recognized as an integral part of numerous cellular programs. Thanks to their diverse physicochemical properties, compartmentalized production, and tight control exerted by the antioxidant machinery they activate signaling pathways that govern plant growth, development, and defense. Excessive ROS levels are often driven by adverse changes in environmental conditions, ultimately causing oxidative stress. The associated negative impact on cellular constituents have been a major focus of decade-long research efforts to improve the oxidative stress resilience by boosting the antioxidant machinery in model and crop species. We highlight the role of enzymatic and non-enzymatic antioxidants as integral factors of multiple signaling cascades beyond their mere function to prevent oxidative damage under adverse abiotic stress conditions.
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Therapeutic potential of flavonoids in cancer: ROS-mediated mechanisms.
Slika, H, Mansour, H, Wehbe, N, Nasser, SA, Iratni, R, Nasrallah, G, Shaito, A, Ghaddar, T, Kobeissy, F, Eid, AH
Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie. 2022;:112442
Abstract
Cancer is a leading cause of morbidity and mortality around the globe. Reactive oxygen species (ROS) play contradicting roles in cancer incidence and progression. Antioxidants have attracted attention as emerging therapeutic agents. Among these are flavonoids, which are natural polyphenols with established anticancer and antioxidant capacities. Increasing evidence shows that flavonoids can inhibit carcinogenesis via suppressing ROS levels. Surprisingly, flavonoids can also trigger excessive oxidative stress, but this can also induce death of malignant cells. In this review, we explore the inherent characteristics that contribute to the antioxidant capacity of flavonoids, and we dissect the scenarios in which they play the contrasting role as pro-oxidants. Furthermore, we elaborate on the pathways that link flavonoid-mediated modulation of ROS to the prevention and treatment of cancer. Special attention is given to the ROS-mediated anticancer functions that (-)-epigallocatechin gallate (EGCG), hesperetin, naringenin, quercetin, luteolin, and apigenin evoke in various cancers. We also delve into the structure-function relations that make flavonoids potent antioxidants. This review provides a detailed perspective that can be utilized in future experiments or trials that aim at utilizing flavonoids or verifying their efficacy for developing new pharmacologic agents. We support the argument that flavonoids are attractive candidates for cancer therapy.
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Hydrogen peroxide-induced stress acclimation in plants.
Qureshi, MK, GawroĊski, P, Munir, S, Jindal, S, Kerchev, P
Cellular and molecular life sciences : CMLS. 2022;(2):129
Abstract
Among all reactive oxygen species (ROS), hydrogen peroxide (H2O2) takes a central role in regulating plant development and responses to the environment. The diverse role of H2O2 is achieved through its compartmentalized synthesis, temporal control exerted by the antioxidant machinery, and ability to oxidize specific residues of target proteins. Here, we examine the role of H2O2 in stress acclimation beyond the well-studied transcriptional reprogramming, modulation of plant hormonal networks and long-distance signalling waves by highlighting its global impact on the transcriptional regulation and translational machinery.
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4.
Use of Thiols in the Treatment of COVID-19: Current Evidence.
Cazzola, M, Rogliani, P, Salvi, SS, Ora, J, Matera, MG
Lung. 2021;(4):335-343
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Abstract
There is a possible role for oxidative stress, a state characterized by an altered balance between the production of free radicals or reactive oxygen species (ROS) and antioxidant defences, in coronavirus disease 2019 (COVID-19), the genesis of which is quite complex. Excessive oxidative stress could be responsible for the alveolar damage, thrombosis, and red blood cell dysregulation observed in COVID-19. Apparently, deficiency of glutathione (GSH), a low-molecular-weight thiol that is the most important non-enzymatic antioxidant molecule and has the potential to keep the cytokine storm in check, is a plausible explanation for the severe manifestations and death in COVID-19 patients. Thiol drugs, which are considered mucolytic, also possess potent antioxidant and anti-inflammatory properties. They exhibit antibacterial activity against a variety of medically important bacteria and may be an effective strategy against influenza virus infection. The importance of oxidative stress during COVID-19 and the various pharmacological characteristics of thiol-based drugs suggest a possible role of thiols in the treatment of COVID-19. Oral and intravenous GSH, as well as GSH precursors such as N-acetylcysteine (NAC), or drugs containing the thiol moiety (erdosteine) may represent a novel therapeutic approach to block NF-kB and address the cytokine storm syndrome and respiratory distress observed in COVID-19 pneumonia patients.
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Oxygen and reactive oxygen species-dependent regulation of plant growth and development.
Considine, MJ, Foyer, CH
Plant physiology. 2021;(1):79-92
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Abstract
Oxygen and reactive oxygen species (ROS) have been co-opted during evolution into the regulation of plant growth, development, and differentiation. ROS and oxidative signals arising from metabolism or phytohormone-mediated processes control almost every aspect of plant development from seed and bud dormancy, liberation of meristematic cells from the quiescent state, root and shoot growth, and architecture, to flowering and seed production. Moreover, the phytochrome and phytohormone-dependent transmissions of ROS waves are central to the systemic whole plant signaling pathways that integrate root and shoot growth. The sensing of oxygen availability through the PROTEOLYSIS 6 (PRT6) N-degron pathway functions alongside ROS production and signaling but how these pathways interact in developing organs remains poorly understood. Considerable progress has been made in our understanding of the nature of hydrogen peroxide sensors and the role of thiol-dependent signaling networks in the transmission of ROS signals. Reduction/oxidation (redox) changes in the glutathione (GSH) pool, glutaredoxins (GRXs), and thioredoxins (TRXs) are important in the control of growth mediated by phytohormone pathways. Although, it is clear that the redox states of proteins involved in plant growth and development are controlled by the NAD(P)H thioredoxin reductase (NTR)/TRX and reduced GSH/GRX systems of the cytosol, chloroplasts, mitochondria, and nucleus, we have only scratched the surface of this multilayered control and how redox-regulated processes interact with other cell signaling systems.
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Deterioration of orthodox seeds during ageing: Influencing factors, physiological alterations and the role of reactive oxygen species.
Zhang, K, Zhang, Y, Sun, J, Meng, J, Tao, J
Plant physiology and biochemistry : PPB. 2021;:475-485
Abstract
Seed viability is an important trait in agriculture which directly influences seedling emergence and crop yield. However, even when stored under optimal conditions, all seeds will eventually lose their viability. Our primary aims were to describe factors influencing seed deterioration, determine the morphological, physiological, and biochemical changes that occur during the process of seed ageing, and explore the mechanisms involved in seed deterioration. High relative humidity and high temperature are two factors that accelerate seed deterioration. As seeds age, frequently observed changes include membrane damage and the destruction of organelle structure, an increase in the loss of seed leachate, decreases of respiratory rates and ATP production, and a loss of enzymatic activity. These phenomena could be inter-related and reflect the general breakdown in cellular organization. Many processes can result in seed ageing; it is likely that oxidative damage caused by free radicals and reactive oxygen species (ROS) is primarily responsible. ROS can have vital interactions with any macromolecule of biological interest that result in damage to various cellular components caused by protein damage, lipid peroxidation, chromosomal abnormalities, and DNA lesions. Further, ROS may also cause programmed cell death by inducing the opening of mitochondrial permeability transition pores and the release of cytochrome C. Some repairs can occur in the early stages of imbibition, but repair processes fail if sufficient damage has been caused to critical functional components. As a result, a given seed will lose its viability and eventually fail to germinate in a relatively short time period.
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Oxidative damage and antioxidants in cervical cancer.
Preci, DP, Almeida, A, Weiler, AL, Mukai Franciosi, ML, Cardoso, AM
International journal of gynecological cancer : official journal of the International Gynecological Cancer Society. 2021;(2):265-271
Abstract
The pathogenesis of cervical cancer is related to oxidative damage caused by persistent infection by one of the oncogenic types of human papillomavirus (HPV). This damage comes from oxidative stress, which is the imbalance caused by the increase in reactive oxygen and nitrogen species and impaired antioxidant mechanisms, promoting tumor progression through metabolic processes. The incorporation of HPV into the cellular genome leads to the expression of oncoproteins, which are associated with chronic inflammation and increased production of reactive oxygen species, oxidizing proteins, lipids and DNA. The increase in these parameters is related, in general, to the reduction of circulating levels of enzymatic antioxidants-superoxide dismutase, catalase, glutathione peroxidase and glutathione-S-transferase; and non-enzymatic antioxidants-reduced glutathione, coenzyme Q10 and vitamins A, C and E, according to tumor staging. In contrast, some enzymatic antioxidants suffer upregulation in the tumor tissue as a way of adapting to the oxidative environment generated by themselves, such as glutathione-S-transferase, reduced glutathione, glutathione peroxidase, superoxide dismutase 2, induced nitric oxide synthase, peroxiredoxins 1, 3 and 6, and thioredoxin reductase 2. The decrease in the expression and activity of certain circulatory antioxidants and increasing the redox status of the tumor cells are thus key to cervical carcinoma prognosis. In addition, vitamin deficit is considered a possible modifiable risk factor by supplementation, since the cellular functions can have a protective effect on the development of cervical cancer. In this review, we will discuss the impact of oxidative damage on cervical cancer progression, as well as the main oxidative markers and therapeutic potentialities of antioxidants.
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Regulation of Reactive Oxygen Species and Antioxidant Defense in Plants under Salinity.
Hasanuzzaman, M, Raihan, MRH, Masud, AAC, Rahman, K, Nowroz, F, Rahman, M, Nahar, K, Fujita, M
International journal of molecular sciences. 2021;(17)
Abstract
The generation of oxygen radicals and their derivatives, known as reactive oxygen species, (ROS) is a part of the signaling process in higher plants at lower concentrations, but at higher concentrations, those ROS cause oxidative stress. Salinity-induced osmotic stress and ionic stress trigger the overproduction of ROS and, ultimately, result in oxidative damage to cell organelles and membrane components, and at severe levels, they cause cell and plant death. The antioxidant defense system protects the plant from salt-induced oxidative damage by detoxifying the ROS and also by maintaining the balance of ROS generation under salt stress. Different plant hormones and genes are also associated with the signaling and antioxidant defense system to protect plants when they are exposed to salt stress. Salt-induced ROS overgeneration is one of the major reasons for hampering the morpho-physiological and biochemical activities of plants which can be largely restored through enhancing the antioxidant defense system that detoxifies ROS. In this review, we discuss the salt-induced generation of ROS, oxidative stress and antioxidant defense of plants under salinity.
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Micronutrient fertilization enhances ROS scavenging system for alleviation of abiotic stresses in plants.
Tavanti, TR, Melo, AAR, Moreira, LDK, Sanchez, DEJ, Silva, RDS, Silva, RMD, Reis, ARD
Plant physiology and biochemistry : PPB. 2021;:386-396
Abstract
Reactive oxygen species (ROS) such as hydrogen peroxide at low concentrations act as signaling of several abiotic stresses. Overproduction of hydrogen peroxide causes the oxidation of plant cell lipid phosphate layer promoting senescence and cell death. To mitigate the effect of ROS, plants develop antioxidant defense mechanisms (superoxide dismutase, catalase, guaiacol peroxidase), ascorbate-glutathione cycle enzymes (ASA-GSH) (ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase and glutathione reductase), which have the function of removing and transforming ROS into non-toxic substances to maintain cellular homeostasis. Foliar or soil application of fertilizers containing B, Cu, Fe, Mn, Mo, Ni, Se and Zn at low concentrations has the ability to elicit and activate antioxidative enzymes, non-oxidizing metabolism, as well as sugar metabolism to mitigate damage by oxidative stress. Plants treated with micronutrients show higher tolerance to abiotic stress and better nutritional status. In this review, we summarized results indicating micronutrient actions in order to reduce ROS resulting the increase of photosynthetic capacity of plants for greater crop yield. This meta-analysis provides information on the mechanism of action of micronutrients in combating ROS, which can make plants more tolerant to several types of abiotic stress such as extreme temperatures, salinity, heavy metals and excess light.
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Melatonin interferes with COVID-19 at several distinct ROS-related steps.
Camp, OG, Bai, D, Gonullu, DC, Nayak, N, Abu-Soud, HM
Journal of inorganic biochemistry. 2021;:111546
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Abstract
Recent studies have shown a correlation between COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and the distinct, exaggerated immune response titled "cytokine storm". This immune response leads to excessive production and accumulation of reactive oxygen species (ROS) that cause clinical signs characteristic of COVID-19 such as decreased oxygen saturation, alteration of hemoglobin properties, decreased nitric oxide (NO) bioavailability, vasoconstriction, elevated cytokines, cardiac and/or renal injury, enhanced D-dimer, leukocytosis, and an increased neutrophil to lymphocyte ratio. Particularly, neutrophil myeloperoxidase (MPO) is thought to be especially abundant and, as a result, contributes substantially to oxidative stress and the pathophysiology of COVID-19. Conversely, melatonin, a potent MPO inhibitor, has been noted for its anti-inflammatory, anti-oxidative, anti-apoptotic, and neuroprotective actions. Melatonin has been proposed as a safe therapeutic agent for COVID-19 recently, having been given with a US Food and Drug Administration emergency authorized cocktail, REGEN-COV2, for management of COVID-19 progression. This review distinctly highlights both how the destructive interactions of HOCl with tetrapyrrole rings may contribute to oxygen deficiency and hypoxia, vitamin B12 deficiency, NO deficiency, increased oxidative stress, and sleep disturbance, as well as how melatonin acts to prevent these events, thereby improving COVID-19 prognosis.