Evidence for age‐related contributions of DNA damage and epigenetics in brain tumorigenesis

Author(s):  
Adrian Tira ◽  
Lela Buckingham
Keyword(s):  
2019 ◽  
Vol 24 (40) ◽  
pp. 4726-4741 ◽  
Author(s):  
Orathai Tangvarasittichai ◽  
Surapon Tangvarasittichai

Background: Oxidative stress is caused by free radicals or oxidant productions, including lipid peroxidation, protein modification, DNA damage and apoptosis or cell death and results in cellular degeneration and neurodegeneration from damage to macromolecules. Results: Accumulation of the DNA damage (8HOdG) products and the end products of LPO (including aldehyde, diene, triene conjugates and Schiff’s bases) were noted in the research studies. Significantly higher levels of these products in comparison with the controls were observed. Oxidative stress induced changes to ocular cells and tissues. Typical changes include ECM accumulation, cell dysfunction, cell death, advanced senescence, disarrangement or rearrangement of the cytoskeleton and released inflammatory cytokines. It is involved in ocular diseases, including keratoconus, Fuchs endothelial corneal dystrophy, and granular corneal dystrophy type 2, cataract, age-related macular degeneration, primary open-angle glaucoma, retinal light damage, and retinopathy of prematurity. These ocular diseases are the cause of irreversible blindness worldwide. Conclusions: Oxidative stress, inflammation and autophagy are implicated in biochemical and morphological changes in these ocular tissues. The development of therapy is a major target for the management care of these ocular diseases.


Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 305
Author(s):  
John-Patrick Alao ◽  
Luc Legon ◽  
Charalampos Rallis

Cells have developed response systems to constantly monitor environmental changes and accordingly adjust growth, differentiation, and cellular stress programs. The evolutionarily conserved, nutrient-responsive, mechanistic target of rapamycin signaling (mTOR) pathway coordinates basic anabolic and catabolic cellular processes such as gene transcription, protein translation, autophagy, and metabolism, and is directly implicated in cellular and organismal aging as well as age-related diseases. mTOR mediates these processes in response to a broad range of inputs such as oxygen, amino acids, hormones, and energy levels, as well as stresses, including DNA damage. Here, we briefly summarize data relating to the interplays of the mTOR pathway with DNA damage response pathways in fission yeast, a favorite model in cell biology, and how these interactions shape cell decisions, growth, and cell-cycle progression. We, especially, comment on the roles of caffeine-mediated DNA-damage override. Understanding the biology of nutrient response, DNA damage and related pharmacological treatments can lead to the design of interventions towards improved cellular and organismal fitness, health, and survival.


Author(s):  
Jacek P. Szaflik ◽  
Katarzyna Janik-Papis ◽  
Ewelina Synowiec ◽  
Dominika Ksiazek ◽  
Magdalena Zaras ◽  
...  

2021 ◽  
Author(s):  
Jason L. Pugh ◽  
Christopher P. Coplen ◽  
Alona S. Sukhina ◽  
Jennifer L. Uhrlaub ◽  
Jose Padilla-Torres ◽  
...  

ABSTRACTA popular “DNA-damage theory” of aging posits that unrepaired DNA damage leads to cellular (and organismal) senescence. Indeed, some hallmarks of immune aging are more prevalent in individuals exposed to Whole-Body Irradiation (WBI). To test this hypothesis in a model relevant to human immune aging, we examined separate and joint effects of lifelong latent Murine Cytomegalovirus (MCMV) and early-life WBI (i) over the course of the lifespan; (ii) in response to a West Nile virus (WNV) live attenuated vaccine; and (iii) following lethal WNV challenge subsequent to vaccination. We recently published that a single dose of non-lethal WBI in youth, on its own, was not sufficient to accelerate aging of the murine immune system despite causing widespread DNA damage and repopulation stress in hematopoietic cells. However, 4Gy sub-lethal WBI caused manifest reactivation of MCMV. Following vaccination and challenge with WNV in the old age, MCMV-infected animals experiencing 4Gy, but not lower, dose of sub-lethal WBI in youth had reduced survival. By contrast, old irradiated mice lacking MCMV and MCMV-infected, but not irradiated, mice were both protected to the same high level as the old non-irradiated, uninfected controls. Analysis of the quality and quantity of anti-WNV immunity showed that higher mortality in MCMV-positive WBI mice correlated with increased levels of MCMV-specific immune activation during WNV challenge. Moreover, we demonstrate that infection, including that by WNV, led to MCMV reactivation. Our data suggest that MCMV reactivation may be an important determinant of increased late-life mortality following early-life irradiation and late-life acute infection.


2020 ◽  
Vol 295 (20) ◽  
pp. 6958-6971
Author(s):  
Chunyan Liao ◽  
Binxiang Cai ◽  
Yufeng Feng ◽  
Jingmeng Chen ◽  
Yiping Wu ◽  
...  

Disrupted clearance of all-trans-retinal (atRAL), a component of the visual (retinoid) cycle in the retina, may cause photoreceptor atrophy in autosomal recessive Stargardt disease (STGD1) and dry age-related macular degeneration (AMD). However, the mechanisms underlying atRAL-induced photoreceptor loss remain elusive. Here, we report that atRAL activates c-Jun N-terminal kinase (JNK) signaling at least partially through reactive oxygen species production, which promoted mitochondria-mediated caspase- and DNA damage-dependent apoptosis in photoreceptor cells. Damage to mitochondria in atRAL-exposed photoreceptor cells resulted from JNK activation, leading to decreased expression of Bcl2 apoptosis regulator (Bcl2), increased Bcl2 antagonist/killer (Bak) levels, and cytochrome c (Cyt c) release into the cytosol. Cytosolic Cyt c specifically provoked caspase-9 and caspase-3 activation and thereby initiated apoptosis. Phosphorylation of JNK in atRAL-loaded photoreceptor cells induced the appearance of γH2AX, a sensitive marker for DNA damage, and was also associated with apoptosis onset. Suppression of JNK signaling protected photoreceptor cells against atRAL-induced apoptosis. Moreover, photoreceptor cells lacking Jnk1 and Jnk2 genes were more resistant to atRAL-associated cytotoxicity. The Abca4−/−Rdh8−/− mouse model displays defects in atRAL clearance that are characteristic of STGD1 and dry AMD. We found that JNK signaling was activated in the neural retina of light-exposed Abca4−/−Rdh8−/− mice. Of note, intraperitoneal administration of JNK–IN-8, which inhibits JNK signaling, effectively ameliorated photoreceptor degeneration and apoptosis in light-exposed Abca4−/−Rdh8−/− mice. We propose that pharmacological inhibition of JNK signaling may represent a therapeutic strategy for preventing photoreceptor loss in retinopathies arising from atRAL overload.


Mutagenesis ◽  
2020 ◽  
Vol 35 (2) ◽  
pp. 169-177 ◽  
Author(s):  
Permal Deo ◽  
Caitlin L McCullough ◽  
Theodora Almond ◽  
Emma L Jaunay ◽  
Leigh Donnellan ◽  
...  

Abstract This study investigated the effect of glucose and fructose, and advanced glycation end-products (AGEs) on genome damage in WIL2-NS cells, measured using the cytokinesis-block micronucleus cytome (CBMN-Cyt) assay. The effect of AGEs was investigated using the bovine serum albumin (AGE-BSA) model system induced either with glucose (Glu–BSA) or with fructose (Fru–BSA). Liquid chromatography-mass spectrometry (LC-MS/MS) analysis showed higher Nε-carboxymethyllysine (CML; 26.76 ± 1.09 nmol/mg BSA) levels in the Glu–BSA model. Nε-Carboxyethyllysine (CEL; 7.87 ± 0.19 nmol/mg BSA) and methylglyoxal-derived hydroimidazolone-1 (MG-H1; 69.77 ± 3.74 nmol/mg BSA) levels were higher in the Fru–BSA model. Genotoxic effects were measured using CBMN-Cyt assay biomarkers [binucleated(BN) cells with micronuclei (MNi), BN with nucleoplasmic bridges (NPBs) and BN with nuclear buds (NBuds)] following 9 days of treatment with either glucose, fructose, Glu–BSA or Fru–BSA. Fructose treatment exerted a significant genotoxic dose–response effect including increases of BN with MNi (R2 = 0.7704; P = 0.0031), BN with NPBs (R2 = 0.9311; P < 0.0001) and BN with NBuds (R2 = 0.7118; P = 0.0091) on cells, whereas the DNA damaging effects of glucose were less evident. High concentrations of AGEs (400–600 µg/ml) induced DNA damage; however, there was no effect on cytotoxicity indices (necrosis and apoptosis). In conclusion, this study demonstrates a potential link between physiologically high concentrations of reducing sugars or AGEs with increased chromosomal damage which is an important emerging aspect of the pathology that may be induced by diabetes. Ultimately, loss of genome integrity could accelerate the rate of ageing and increase the risk of age-related diseases over the long term. These findings indicate the need for further research on the effects of glycation on chromosomal instability and to establish whether this effect is replicated in humans in vivo.


2020 ◽  
Vol 21 (10) ◽  
pp. 3720 ◽  
Author(s):  
Kazuhiro Hitomi ◽  
Ryo Okada ◽  
Tze Mun Loo ◽  
Kenichi Miyata ◽  
Asako J. Nakamura ◽  
...  

DNA damage, caused by various oncogenic stresses, can induce cell death or cellular senescence as an important tumor suppressor mechanism. Senescent cells display the features of a senescence-associated secretory phenotype (SASP), secreting inflammatory proteins into surrounding tissues, and contributing to various age-related pathologies. In addition to this inflammatory protein secretion, the release of extracellular vesicles (EVs) is also upregulated in senescent cells. However, the molecular mechanism underlying this phenomenon remains unclear. Here, we show that DNA damage activates the ceramide synthetic pathway, via the downregulation of sphingomyelin synthase 2 (SMS2) and the upregulation of neutral sphingomyelinase 2 (nSMase2), leading to an increase in senescence-associated EV (SA-EV) biogenesis. The EV biogenesis pathway, together with the autophagy-mediated degradation pathway, functions to block apoptosis by removing cytoplasmic DNA fragments derived from chromosomal DNA or bacterial infections. Our data suggest that this SA-EV pathway may play a prominent role in cellular homeostasis, particularly in senescent cells. In summary, DNA damage provokes SA-EV release by activating the ceramide pathway to protect cells from excessive inflammatory responses.


Cells ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 597
Author(s):  
Vijayasree V. Giridharan ◽  
Vengadeshprabhu Karupppagounder ◽  
Somasundaram Arumugam ◽  
Yutaka Nakamura ◽  
Ashrith Guha ◽  
...  

Aging is a predominant risk factor for the development and progression of cardiovascular complications. Physiologically and anatomically, the heart undergoes numerous changes that result in poor cardiac function in the elderly population. Recently, several studies have provided promising results, confirming the ability of the senescence-accelerated mouse-prone 8 (SAMP8) model to accurately model age-related cardiovascular alterations. In this study, using a murine model of senescence, SAMP8, we aimed to investigate the effect of 3,4-dihydroxybenzalacetone (DBL), a catechol-containing phenylpropanoid derivative isolated from Inonotus obliquus (Chaga), on cardiac aging. DBL was administered at the doses of 10 mg/kg and 20 mg/kg by oral gavage to SAMP8 mice to examine aging-mediated cardiac changes, such as oxidative DNA damage, oxygen radical antioxidant capacity (ORAC) value, fibrosis, inflammation, and apoptosis. The treatment with DBL at both doses significantly reduced aging-mediated oxidative DNA damage, and simultaneously increased the ORAC value in the SAMP8 assay. Cardiac fibrosis was assessed with Azan-Mallory staining, and the number of cardiac remodeling markers was found to be significantly reduced after the treatment with DBL. We also observed a decrease in cardiomyocyte apoptosis as measured by the terminal transferase-mediated dUTP nick end labeling (TUNEL) staining method and the caspase-3 levels in SAMP8 mice compared with senescence-resistant control (SAMR1) mice. The findings from this study suggest that DBL has a potentially beneficial effect on aging-mediated myocardial alterations. Further studies are warranted to confirm the promising potential of this catechol compound against aging-associated myocardial dysfunction.


Open Biology ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 190168 ◽  
Author(s):  
Paulo F. L. da Silva ◽  
Björn Schumacher

Ageing appears to be a nearly universal feature of life, ranging from unicellular microorganisms to humans. Longevity depends on the maintenance of cellular functionality, and an organism's ability to respond to stress has been linked to functional maintenance and longevity. Stress response pathways might indeed become therapeutic targets of therapies aimed at extending the healthy lifespan. Various progeroid syndromes have been linked to genome instability, indicating an important causal role of DNA damage accumulation in the ageing process and the development of age-related pathologies. Recently, non-cell-autonomous mechanisms including the systemic consequences of cellular senescence have been implicated in regulating organismal ageing. We discuss here the role of cellular and systemic mechanisms of ageing and their role in ageing-associated diseases.


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