scholarly journals Targeted Antioxidants in Exercise-Induced Mitochondrial Oxidative Stress: Emphasis on DNA Damage

Antioxidants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1142 ◽  
Author(s):  
Josh Williamson ◽  
Gareth Davison

Exercise simultaneously incites beneficial (e.g., signal) and harming (e.g., damage to macromolecules) effects, likely through the generation of reactive oxygen and nitrogen species (RONS) and downstream changes to redox homeostasis. Given the link between nuclear DNA damage and human longevity/pathology, research attempting to modulate DNA damage and restore redox homeostasis through non-selective pleiotropic antioxidants has yielded mixed results. Furthermore, until recently the role of oxidative modifications to mitochondrial DNA (mtDNA) in the context of exercising humans has largely been ignored. The development of antioxidant compounds which specifically target the mitochondria has unveiled a number of exciting avenues of exploration which allow for more precise discernment of the pathways involved with the generation of RONS and mitochondrial oxidative stress. Thus, the primary function of this review, and indeed its novel feature, is to highlight the potential roles of mitochondria-targeted antioxidants on perturbations to mitochondrial oxidative stress and the implications for exercise, with special focus on mtDNA damage. A brief synopsis of the current literature addressing the sources of mitochondrial superoxide and hydrogen peroxide, and available mitochondria-targeted antioxidants is also discussed.

2020 ◽  
Vol 21 (14) ◽  
pp. 5048
Author(s):  
Chih-Wei Chen ◽  
Ning Tsao ◽  
Wei Zhang ◽  
Zee-Fen Chang

NME3 is a member of the nucleoside diphosphate kinase (NDPK) family that binds to the mitochondrial outer membrane to stimulate mitochondrial fusion. In this study, we showed that NME3 knockdown delayed DNA repair without reducing the cellular levels of nucleotide triphosphates. Further analyses revealed that NME3 knockdown increased fragmentation of mitochondria, which in turn led to mitochondrial oxidative stress-mediated DNA single-strand breaks (SSBs) in nuclear DNA. Re-expression of wild-type NME3 or inhibition of mitochondrial fission markedly reduced SSBs and facilitated DNA repair in NME3 knockdown cells, while expression of N-terminal deleted mutant defective in mitochondrial binding had no rescue effect. We further showed that disruption of mitochondrial fusion by knockdown of NME4 or MFN1 also caused mitochondrial oxidative stress-mediated genome instability. In conclusion, the contribution of NME3 to redox-regulated genome stability lies in its function in mitochondrial fusion.


Hypertension ◽  
2017 ◽  
Vol 70 (suppl_1) ◽  
Author(s):  
Rodrigo O Maranon ◽  
Carolina Dalmasso ◽  
Chetal N Patil ◽  
Jane F Reckelhoff

Men have higher blood pressure (BP) than premenopausal women. Pressor response to oxidative stress may be a major contributor to the sex difference in BP control. Mitochondrial oxidative stress is associated with hypertension; however, whether mitochondrial oxidative stress plays a role in the sex difference in BP is unknown. In the present study, we tested the hypothesis that mitochondrial oxidative stress contributes to the sex difference in BP regulation in spontaneously hypertensive rats (SHR). Young intact (iYMSHR) and castrated males (cYMSHR), and females SHR (YFSHR) (3 mos of age) were implanted with radiotelemeters, and after a 4 day baseline BP, were treated with mitoTempo (0.75 mg/kg/d, sc minipumps), a specific scavenger of mitochondrial superoxide, for 7 days. Following 10 days washout of mito-tempo, rats were treated with Tempol (30 mg/kg/day, po drinking water) for 7 days. iYMSHR have higher blood pressure (by telemetry) than cYMSHR and YFSHR (148±1 mmHg, n=5, vs 132±1 mmHg, n=5, and 139±1 mmHg, n=5; p<0.01, respectively). MitoTempo reduced BP by 6% in iYMSHR (147±1 vs 139±1, n=5; p<0.05) compared to females (3%: 139±1 vs 136±1; n=5; p: NS) and castrated males (4.5%: 132±1 vs 126±1, n=5; p<0.05). After 10 days washout, tempol reduced BP only in iYMSHR (144±1 vs 130±1 mmHg, n=5; p<0.05). Our results suggest that mitochondrial oxidative stress may contribute to BP regulation in male SHR, but has no effect in females. The data also suggest that the presence of testosterone is necessary for the pressor response to oxidative stress in males since Tempol had no effect on BP in castrated males. Further studies examining the effect of steroid hormones and mitochondria in BP regulation are necessary to elucidate the importance of mitochondrial oxidative stress on sex difference of hypertension.


2008 ◽  
Vol 29 (3) ◽  
pp. 794-807 ◽  
Author(s):  
Lyra M. Griffiths ◽  
Dan Swartzlander ◽  
Kellen L. Meadows ◽  
Keith D. Wilkinson ◽  
Anita H. Corbett ◽  
...  

ABSTRACT DNAs harbored in both nuclei and mitochondria of eukaryotic cells are subject to continuous oxidative damage resulting from normal metabolic activities or environmental insults. Oxidative DNA damage is primarily reversed by the base excision repair (BER) pathway, initiated by N-glycosylase apurinic/apyrimidinic (AP) lyase proteins. To execute an appropriate repair response, BER components must be distributed to accommodate levels of genotoxic stress that may vary considerably between nuclei and mitochondria, depending on the growth state and stress environment of the cell. Numerous examples exist where cells respond to signals, resulting in relocalization of proteins involved in key biological transactions. To address whether such dynamic localization contributes to efficient organelle-specific DNA repair, we determined the intracellular localization of the Saccharomyces cerevisiae N-glycosylase/AP lyases, Ntg1 and Ntg2, in response to nuclear and mitochondrial oxidative stress. Fluorescence microscopy revealed that Ntg1 is differentially localized to nuclei and mitochondria, likely in response to the oxidative DNA damage status of the organelle. Sumoylation is associated with targeting of Ntg1 to nuclei containing oxidative DNA damage. These studies demonstrate that trafficking of DNA repair proteins to organelles containing high levels of oxidative DNA damage may be a central point for regulating BER in response to oxidative stress.


2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Na Zhang ◽  
Lingyan Wang ◽  
Qi Duan ◽  
Laixiang Lin ◽  
Mohamed Ahmed ◽  
...  

Purpose. We aim to figure out the effect of metallothioneins on iodide excess induced oxidative stress in the thyroid.Methods. Eight-week-old MT-I/II knockout (MT-I/II KO) mice and background-matched wild-type (WT) mice were used. Mitochondrial superoxide production and peroxiredoxin (Prx) 3 expression were measured.Results. In in vitro study, more significant increases in mitochondrial superoxide production and Prx 3 expression were detected in the MT-I/II KO groups. In in vivo study, significantly higher concentrations of urinary iodine level were detected in MT-I/II KO mice in 100 HI group. Compared to the NI group, there was no significant difference existing in serum thyroid hormones level in either groups (P>0.05), while the mitochondrial superoxide production was significantly increased in 100 HI groups with significantly increased LDH activity and decreased relative cell viability. Compared to WT mice, more significant changes were detected in MT-I/II KO mice in 100 HI groups. No significant differences were detected between the NI group and 10 HI group in both the MT-I/II KO and WT mice groups (P>0.05).Conclusions. Iodide excess in a thyroid without MT I/II protection may result in strong mitochondrial oxidative stress, which further leads to the damage of thyrocytes.


2021 ◽  
Author(s):  
Yanying Huo ◽  
Akshada Sawant ◽  
Yongmei Tan ◽  
Amar H Mahdi ◽  
Tao Li ◽  
...  

The PALB2 tumor suppressor plays key roles in DNA repair and has been implicated in redox homeostasis. Autophagy maintains mitochondrial quality, mitigates oxidative stress and suppresses neurodegeneration. Here we show that Palb2 deletion in the mouse brain leads to motor deficits and that co-deletion of Palb2 with the essential autophagy gene Atg7 accelerates and exacerbates neurodegeneration induced by ATG7 loss. Palb2 deletion leads to elevated DNA damage, oxidative stress and mitochondrial markers, especially in Purkinje cells, and co-deletion of Palb2 and Atg7 results in accelerated Purkinje cell loss. Further analyses suggest that the accelerated Purkinje cell loss and severe neurodegeneration in the double deletion mice are due to oxidative stress and mitochondrial dysfunction, rather than DNA damage, and partially dependent on p53 activity. Our studies uncover a role of PALB2 in mitochondrial regulation and a cooperation between PALB2 and ATG7/autophagy in maintaining redox and mitochondrial homeostasis essential for neuronal survival.


Oncogene ◽  
2021 ◽  
Author(s):  
Xiaohe Hao ◽  
Wenqing Bu ◽  
Guosheng Lv ◽  
Limei Xu ◽  
Dong Hou ◽  
...  

AbstractReactive oxygen species (ROS) serve as critical signals in various cellular processes. Excessive ROS cause cell death or senescence and mediates the therapeutic effect of many cancer drugs. Recent studies showed that ROS increasingly accumulate during G2/M arrest, the underlying mechanism, however, has not been fully elucidated. Here, we show that in cancer cells treated with anticancer agent TH287 or paclitaxel that causes M arrest, mitochondria accumulate robustly and produce excessive mitochondrial superoxide, which causes oxidative DNA damage and undermines cell survival and proliferation. While mitochondrial mass is greatly increased in cells arrested at M phase, the mitochondrial function is compromised, as reflected by reduced mitochondrial membrane potential, increased SUMOylation and acetylation of mitochondrial proteins, as well as an increased metabolic reliance on glycolysis. CHK1 functional disruption decelerates cell cycle, spares the M arrest and attenuates mitochondrial oxidative stress. Induction of mitophagy and blockade of mitochondrial biogenesis, measures that reduce mitochondrial accumulation, also decelerate cell cycle and abrogate M arrest-coupled mitochondrial oxidative stress. These results suggest that cell cycle progression and mitochondrial homeostasis are interdependent and coordinated, and that impairment of mitochondrial homeostasis and the associated redox signaling may mediate the antineoplastic effect of the M arrest-inducing chemotherapeutics. Our findings provide insights into the fate of cells arrested at M phase and have implications in cancer therapy.


2021 ◽  
Author(s):  
Victoriane Peugnet ◽  
Maggy Chwastyniak ◽  
Steve Lancel ◽  
Laurent Bultot ◽  
Natacha Fourny ◽  
...  

AbstractHeart failure, mostly associated with cardiac hypertrophy, is still a major cause of illness and death. Oxidative stress causes contractile failure and the accumulation of reactive oxygen species leads to mitochondrial dysfunction, associated with aging and heart failure, suggesting that mitochondria-targeted therapies could be effective in this context. The purpose of this work was to characterize how mitochondrial oxidative stress is involved in cardiac hypertrophy development and to determine if mitochondria-targeted therapies could improve cardiac phenotypes. We used neonatal and adult rat cardiomyocytes (NCMs and ACMs) hypertrophied by isoproterenol (Iso) to induce an increase of mitochondrial superoxide anion. Superoxide dismutase 2 activity and mitochondrial biogenesis were significantly decreased after 24h of Iso treatment. To counteract the mitochondrial oxidative stress induced by hypertrophy, we evaluated the impact of two different anti-oxidants, mitoquinone (MitoQ) and EUK 134. Both significantly decreased mitochondrial superoxide anion and hypertrophy in hypertrophied NCMs and ACMs. Conversely to EUK 134 which preserved cell functions, MitoQ impaired mitochondrial function by decreasing maximal mitochondrial respiration, mitochondrial membrane potential and mitophagy (particularly Parkin expression) and altering mitochondrial structure. The same decrease of Parkin was found in human cardiomyocytes but not in fibroblasts suggesting a cell specificity deleterious effect of MitoQ. Our data showed the importance of mitochondrial oxidative stress in the development of cardiomyocyte hypertrophy. Interestingly, we observed that targeting mitochondria by an anti-oxidant (MitoQ) impaired metabolism specifically in cardiomyocytes. Conversely, the SOD mimic (EUK 134) decreased both oxidative stress and cardiomyocyte hypertrophy and restored impaired cardiomyocyte metabolism and mitochondrial biogenesis.


Reproduction ◽  
2001 ◽  
pp. 497-506 ◽  
Author(s):  
RJ Aitken ◽  
C Krausz

Recent advances in understanding of male infertility have implicated two major causative factors, oxidative stress and Y chromosome deletions. A major cause of oxidative stress appears to be the high rate of reactive oxygen species generation associated with the retention of excess residual cytoplasm in the sperm midpiece. Other possible causes include the redox cycling of xenobiotics, and antioxidant depletion or apoptosis. Oxidative stress induces peroxidative damage in the sperm plasma membrane and DNA damage in both the mitochondrial and nuclear genomes. Nuclear DNA damage in the germ line of the father may be associated with pathology in the offspring, including childhood cancer and infertility. Gene deletions on the non-recombining region of the Y chromosome account for the infertility observed in about 15% of patients with azoospermia and 5-10% of subjects with severe oligozoospermia. The Y chromosome is particularly susceptible to gene deletions because of the inability of the haploid genome to deploy recombination repair in retrieving lost genetic information. Aberrant recombination, defective chromatin packaging, abortive apoptosis and oxidative stress may all be involved in the aetiology of DNA damage in the germ line. The factors responsible for Y chromosome deletions in spermatozoa remain unresolved but may be one facet of a central reproductive problem: controlling the amount of oxidative stress experienced by germ cells during their differentiation and maturation in the male reproductive tract.


2006 ◽  
Vol 8 (9-10) ◽  
pp. 1737-1744 ◽  
Author(s):  
Hiroyuki Tsutsui ◽  
Tomomi Ide ◽  
Shintaro Kinugawa

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