Stress-induced DNA damage biomarkers: applications and limitations

Lignin-Based Antioxidant Hydrogel Patch for the Management of Atopic Dermatitis by Mitigating Oxidative Stress in the Skin

Atopic dermatitis (AD), a chronic skin condition characterized by itching, redness, and inflammation, is closely associated with heightened levels of endogenous reactive oxygen species (ROS) in the skin. ROS can contribute to the onset and progression of AD through oxidative stress, which leads to the release of proinflammatory cytokines, T-cell differentiation, and the exacerbation of skin symptoms. In this study, we aim to develop a therapeutic antioxidant hydrogel patch for the potential treatment of AD using lignin, a biomass waste material. Lignin contains polyphenol groups that enable it to scavenge ROS and exhibit antioxidant properties. The lignin hydrogel patches, possessing optimized mechanical properties through the control of the lignin and cross-linker ratio, demonstrated high ROS-scavenging capabilities. Furthermore, the lignin hydrogel demonstrated excellent biocompatibility with the skin, exhibiting beneficial properties in protecting human keratinocytes under high oxidative conditions. When applied to an AD mouse model, the hydrogel patch effectively reduced epidermal thickness in inflamed regions, decreased mast cell infiltration, and regulated inflammatory cytokine levels. These findings collectively suggest that lignin serves as a therapeutic hydrogel patch for managing AD by modulating oxidative stress through its ROS-scavenging ability.

Integrating evolutionarily conserved mechanism of response to radiation for exploring novel Caenorhabditis elegans radiation-responsive genes for estimation of radiation dose associated with spaceflight

During space exploration, space radiation is widely recognized as an inescapable perilous stressor, owing to its capacity to induce genomic DNA damage and escalate the likelihood of detrimental health outcomes. Rapid and reliable estimation of space radiation dose holds paramount significance in accurately assessing the health risks associated with spaceflight. However, the identification of space radiation-responsive genes, with their potential to serve as early indicators for diagnosing radiation dose associated with spaceflight, continues to pose a significant challenge. In this study, based on the evolutionarily conserved mechanism of radiation response, an in silico analysis method of homologous comparison was performed to identify the Caenorhabditis elegans orthologues of human radiation-responsive genes with possible roles in the major processes of response to radiation, and thereby to explore the potential C. elegans radiation-responsive genes for evaluating the levels of space radiation exposure. The results showed that there were 60 known C. elegans radiation-responsive genes and 211 C. elegans orthologues of human radiation-responsive genes implicated in the major processes of response to radiation. Through an investigation of all available transcriptomic datasets obtained from space-flown C. elegans, it was observed that the expression levels of the majority of these putative C. elegans radiation-responsive genes identified in this study were notably changed across various spaceflight conditions. Furthermore, this study indicated that within the identified genes, 19 known C. elegans radiation-responsive genes and 40 newly identified C. elegans orthologues of human radiation-responsive genes exhibited a remarkable positive correlation with the duration of spaceflight. Moreover, a noteworthy presence of substantial multi-collinearity among the majority of these identified genes was observed. This observation lends support to the possibility of treating each identified gene as an independent indicator of radiation dose in space. Ultimately, a subset of 15 potential radiation-responsive genes was identified, presenting the most promising indicators for estimation of radiation dose associated with spaceflight in C. elegans.

DAMPs and radiation injury

The heightened risk of ionizing radiation exposure, stemming from radiation accidents and potential acts of terrorism, has spurred growing interests in devising effective countermeasures against radiation injury. High-dose ionizing radiation exposure triggers acute radiation syndrome (ARS), manifesting as hematopoietic, gastrointestinal, and neurovascular ARS. Hematopoietic ARS typically presents with neutropenia and thrombocytopenia, while gastrointestinal ARS results in intestinal mucosal injury, often culminating in lethal sepsis and gastrointestinal bleeding. This deleterious impact can be attributed to radiation-induced DNA damage and oxidative stress, leading to various forms of cell death, such as apoptosis, necrosis and ferroptosis. Damage-associated molecular patterns (DAMPs) are intrinsic molecules released by cells undergoing injury or in the process of dying, either through passive or active pathways. These molecules then interact with pattern recognition receptors, triggering inflammatory responses. Such a cascade of events ultimately results in further tissue and organ damage, contributing to the elevated mortality rate. Notably, infection and sepsis often develop in ARS cases, further increasing the release of DAMPs. Given that lethal sepsis stands as a major contributor to the mortality in ARS, DAMPs hold the potential to function as mediators, exacerbating radiation-induced organ injury and consequently worsening overall survival. This review describes the intricate mechanisms underlying radiation-induced release of DAMPs. Furthermore, it discusses the detrimental effects of DAMPs on the immune system and explores potential DAMP-targeting therapeutic strategies to alleviate radiation-induced injury.

Differential Gene Expression in Human Fibroblasts Simultaneously Exposed to Ionizing Radiation and Simulated Microgravity

During future space missions, astronauts will be exposed to cosmic radiation and microgravity (μG), which are known to be health risk factors. To examine the differentially expressed genes (DEG) and their prevalent biological processes and pathways as a response to these two risk factors simultaneously, 1BR-hTERT human fibroblast cells were cultured under 1 gravity (1G) or simulated μG for 48 h in total and collected at 0 (sham irradiated), 3 or 24 h after 1 Gy of X-ray or Carbon-ion (C-ion) irradiation. A three-dimensional clinostat was used for the simulation of μG and the simultaneous radiation exposure of the samples. The RNA-seq method was used to produce lists of differentially expressed genes between different environmental conditions. Over-representation analyses were performed and the enriched biological pathways and targeting transcription factors were identified. Comparing sham-irradiated cells under simulated μG and 1G conditions, terms related to response to oxygen levels and muscle contraction were identified. After irradiation with X-rays or C-ions under 1G, identified DEGs were found to be involved in DNA damage repair, signal transduction by p53 class mediator, cell cycle arrest and apoptosis pathways. The same enriched pathways emerged when cells were irradiated under simulated μG condition. Nevertheless, the combined effect attenuated the transcriptional response to irradiation which may pose a subtle risk in space flights.

Nanoparticles in plant resistance against bacterial pathogens: current status and future prospects

Nanoparticles (NPs) serve immense roles in various fields of science. They have vastly upgraded conventional methods in the fields of agriculture and food sciences to eliminate growing threats of crop damage and disease, caused by various phytopathogens including bacteria, fungi, viruses, and some insects. Bacterial diseases resulted in mass damage of crops by adopting antibacterial resistance, which has proved to be a major threat leading to food scarcity. Therefore, numerous NPs with antibacterial potentials have been formulated to overcome the problem of antibiotic resistance alongside an increase in crop yield and boosting plant immunity. NPs synthesized through green synthesis techniques have proved to be more effective and environment-friendly than those synthesized via chemical methods. NPs exhibit great roles in plants ranging from enhanced crop yield to disease suppression, to targeted drug and pesticide deliveries inside the plants and acting as biosensors for pathogen detection. NPs serves major roles in disruption of cellular membranes, ROS production, altering of DNA and protein entities and changing energy transductions. This review focuses on the antibacterial effect of NPs on several plant bacterial pathogens, mostly, against Pseudomonas syringe, Ralstonia solanacearum, Xanthomonas axonopodis, Clavibacter michiganensisand Pantoea ananatis both in vivo and ex vivo, thereby minimizing their antibacterial resistance and enhancing the plants acquired immunity. Therefore, NPs present a safer and more reliable bactericidal activity against various disease-causing bacteria in plants.

Discovery adductomics provides a comprehensive portrait of tissue-, age- and sex-specific DNA modifications in rodents and humans

DNA damage causes genomic instability underlying many diseases, with traditional analytical approaches providing minimal insight into the spectrum of DNA lesions in vivo. Here we used untargeted chromatography-coupled tandem mass spectrometry-based adductomics (LC-MS/MS) to begin to define the landscape of DNA modifications in rat and human tissues. A basis set of 114 putative DNA adducts was identified in heart, liver, brain, and kidney in 1-26-month-old rats and 111 in human heart and brain by 'stepped MRM' LC-MS/MS. Subsequent targeted analysis of these species revealed species-, tissue-, age- and sex-biases. Structural characterization of 10 selected adductomic signals as known DNA modifications validated the method and established confidence in the DNA origins of the signals. Along with strong tissue biases, we observed significant age-dependence for 36 adducts, including N2-CMdG, 5-HMdC and 8-Oxo-dG in rats and 1,N6-ϵdA in human heart, as well as sex biases for 67 adducts in rat tissues. These results demonstrate the potential of adductomics for discovering the true spectrum of disease-driving DNA adducts. Our dataset of 114 putative adducts serves as a resource for characterizing dozens of new forms of DNA damage, defining mechanisms of their formation and repair, and developing them as biomarkers of aging and disease.

Analysis of nuclear maturation, DNA damage and repair gene expression of bovine oocyte and cumulus cells submitted to ionizing radiation

Radiotherapy causes destruction of tumor cells, but also threatens the integrity and survival of surrounding normal cells. Then, woman submitted to irradiation for cancer treatment may present permanent ovary damage, resulting in impaired fertility. The objective of this study was to investigate the effects of therapeutic doses of ionizing radiation (IR), used for ovarian cancer treatment in humans, on bovine cumulus-oocyte complexes (COCs) as experimental model. Bovine ovaries were exposed to 0.9 Gy, 1.8 Gy, 3.6 Gy or 18.6 Gy IR, and then COCs were collected and used to evaluate: (a) oocyte nuclear maturation; (b) presence of phosphorylated H2A.X (γH2AX), as an indicator of DNA double-strand breaks (DSBs); and (c) expression of genes involved in DNA repair (TP53BP1, RAD52, ATM, XRCC6 and XRCC5) and apoptosis (BAX). The radiation doses tested in this study had no detrimental effects on nuclear maturation and did not increase γH2AX in the oocytes. However, IR treatment altered the mRNA abundance of RAD52 (RAD52 homolog, DNA repair protein) and BAX (BCL2-associated X protein). We conclude that although IR doses had no apparent effect on oocyte nuclear maturation and DNA damage, molecular pathways involved in DNA repair and apoptosis were affected by IR exposure in cumulus cells.

Toxic effects of the wastewater produced by underwater hull cleaning equipment on the copepod Tigriopus japonicus

Unmanaged disposal of wastewater produced by underwater hull cleaning equipment (WHCE) is suspected to induce toxic effects to marine organisms because wastewater contains several anti-fouling compounds. To investigate the effects of WHCE on marine copepod, we examined the toxicity on life parameters (e.g. mortality, development, and fecundity) and gene expression changes of Tigriopus japonicus as model organism. Significant mortality and developmental time changes were observed in response to wastewater. No significant differences in fecundity were observed. Transcriptional profiling with differentially expressed genes from WHCE exposed T. japonicus showed WHCE may induce genotoxicity associated genes and pathways. In addition, potentially neurotoxic effects were evident following exposure to WHCE. The findings suggest that wastewater released during hull cleaning should be managed to reduce physiological and molecular deleterious effects in marine organisms.

DNA damage and up-regulation of PARP-1 induced by columbin in vitro and in vivo

Columbin (CLB) is the most abundant (>1.0%) furan-containing diterpenoid lactone in herbal medicine Tinospora sagittate (Oliv.) Gagnep. The furano-terpenoid was found to be hepatotoxic, but the exact mechanisms remain unknown. The present study demonstrated that administration of CLB at 50 mg/kg induced hepatotoxicity, DNA damage and up-regulation of PARP-1 in vivo. Exposure to CLB (10 μM) induced GSH depletion, over-production of ROS, DNA damage, up-regulation of PARP-1 and cell death in cultured mouse primary hepatocytes in vitro. Co-treatment of mouse primary hepatocytes with ketoconazole (10 μM) or glutathione ethyl ester (200 μM) attenuated the GSH depletion, over-production of ROS, DNA damage, up-regulation of PARP-1, and cell death induced by CLB, while co-exposure to L-buthionine sulfoximine (BSO, 1000 μM) intensified such adverse effects resulting from CLB exposure. These results suggest that the metabolic activation of CLB by CYP3A resulted in the depletion of GSH and increase of ROS formation. The resultant over-production of ROS subsequently disrupted the DNA integrity and up-regulated the expression of PARP-1 in response to DNA damage, and ROS-induced DNA damage was involved in the hepatotoxicity of CLB.

Preliminary Toxicological Analysis in a Safe-by-Design and Adverse Outcome Pathway-Driven Approach on Different Silver Nanoparticles: Assessment of Acute Responses in A549 Cells

Silver nanoparticles (Ag NPs) are among the most widely used metal-based nanomaterials (NMs) and their applications in different products, also as antibacterial additives, are increasing. In the present manuscript, according to an adverse outcome pathway (AOP) approach, we tested two safe-by-design (SbD) newly developed Ag NPs coated with hydroxyethyl cellulose (HEC), namely AgHEC powder and AgHEC solution. These novel Ag NPs were compared to two reference Ag NPs (naked and coated with polyvinylpyrrolidone-PVP). Cell viability, inflammatory response, reactive oxygen species, oxidative DNA damage, cell cycle, and cell-particle interactions were analyzed in the alveolar in vitro model, A549 cells. The results show a different toxicity pattern of the novel Ag NPs compared to reference NPs and that between the two novel NPs, the AgHEC solution is the one with the lower toxicity and to be further developed within the SbD framework.

A Review of Radiation-Induced Alterations of Multi-Omic Profiles, Radiation Injury Biomarkers, and Countermeasures

Increasing utilization of nuclear power enhances the risks associated with industrial accidents, occupational hazards, and the threat of nuclear terrorism. Exposure to ionizing radiation interferes with genomic stability and gene expression resulting in the disruption of normal metabolic processes in cells and organs by inducing complex biological responses. Exposure to high-dose radiation causes acute radiation syndrome, which leads to hematopoietic, gastrointestinal, cerebrovascular, and many other organ-specific injuries. Altered genomic variations, gene expression, metabolite concentrations, and microbiota profiles in blood plasma or tissue samples reflect the whole-body radiation injuries. Hence, multi-omic profiles obtained from high-resolution omics platforms offer a holistic approach for identifying reliable biomarkers to predict the radiation injury of organs and tissues resulting from radiation exposures. In this review, we performed a literature search to systematically catalog the radiation-induced alterations from multi-omic studies and radiation countermeasures. We covered radiation-induced changes in the genomic, transcriptomic, proteomic, metabolomic, lipidomic, and microbiome profiles. Furthermore, we have covered promising multi-omic biomarkers, FDA-approved countermeasure drugs, and other radiation countermeasures that include radioprotectors and radiomitigators. This review presents an overview of radiation-induced alterations of multi-omics profiles and biomarkers, and associated radiation countermeasures.

HslO ameliorates arrested ΔrecA polA cell growth and reduces DNA damage and oxidative stress responses

Chromosome damage combined with defective recombinase activity has been widely considered to render cells inviable, owing to deficient double-strand break repair. However, temperature-sensitive recAts polA cells grow well upon induction of DNA damage and supplementation with catalase at restrictive temperatures. These treatments reduce intracellular reactive oxygen species (ROS) levels, which suggests that recAts polA cells are susceptible to ROS, but not chronic chromosome damage. Therefore, we investigated whether polA cells can tolerate a complete lack of recombinase function. We introduced a ΔrecA allele in polA cells in the presence or absence of the hslO-encoding redox molecular chaperon Hsp33 expression plasmid. Induction of the hslO gene with IPTG resulted in increased cell viability in ΔrecA polA cells with the hslO expression plasmid. ΔrecA polA cells in the absence of the hslO expression plasmid showed rich medium sensitivity with increasing ROS levels. Adding catalase to the culture medium considerably rescued growth arrest and decreased ROS. These results suggest that hslO expression manages oxidative stress to an acceptable level in cells with oxidative damage and rescues cell growth. Overall, ROS may regulate several processes, from damage response to cell division, via ROS-sensitive cell metabolism.

Effects of elevated temperature on 8-OHdG expression in the American oyster (Crassostrea virginica): Induction of oxidative stress biomarkers, cellular apoptosis, DNA damage and γH2AX signaling pathways

Global temperature is increasing due to anthropogenic activities and the effects of elevated temperature on DNA lesions are not well documented in marine organisms. The American oyster (Crassostrea virginica, an edible and commercially important marine mollusk) is an ideal shellfish species to study oxidative DNA lesions during heat stress. In this study, we examined the effects of elevated temperatures (24, 28, and 32 °C for one-week exposure) on heat shock protein-70 (HSP70, a biomarker of heat stress), 8‑hydroxy-2'-deoxyguanosine (8-OHdG, a biomarker of pro-mutagenic DNA lesion), double-stranded DNA (dsDNA), γ-histone family member X (γH2AX, a molecular biomarker of DNA damage), caspase-3 (CAS-3, a key enzyme of apoptotic pathway) and Bcl-2-associated X (BAX, an apoptosis regulator) protein and/or mRNA expressions in the gills of American oysters. Immunohistochemical and qRT-PCR results showed that HSP70, 8-OHdG, dsDNA, and γH2AX expressions in gills were significantly increased at high temperatures (28 and 32 °C) compared with control (24°C). In situ TUNEL analysis showed that the apoptotic cells in gill tissues were increased in heat-exposed oysters. Interestingly, the enhanced apoptotic cells were associated with increased CAS-3 and BAX mRNA and/or protein expressions, along with 8-OHdG levels in gills after heat exposure. Moreover, the extrapallial (EP) fluid (i.e., extracellular body fluid) protein concentrations were lower; however, the EP glucose levels were higher in heat-exposed oysters. Taken together, these results suggest that heat shock-driven oxidative stress alters extracellular body fluid conditions and induces cellular apoptosis and DNA damage, which may lead to increased 8-OHdG levels in cells/tissues in oysters.

Clustered DNA Damage Patterns after Proton Therapy Beam Irradiation Using Plasmid DNA

Modeling ionizing radiation interaction with biological matter is a major scientific challenge, especially for protons that are nowadays widely used in cancer treatment. That presupposes a sound understanding of the mechanisms that take place from the early events of the induction of DNA damage. Herein, we present results of irradiation-induced complex DNA damage measurements using plasmid pBR322 along a typical Proton Treatment Plan at the MedAustron proton and carbon beam therapy facility (energy 137-198 MeV and Linear Energy Transfer (LET) range 1-9 keV/μm), by means of Agarose Gel Electrophoresis and DNA fragmentation using Atomic Force Microscopy (AFM). The induction rate Mbp^-1 Gy^-1 for each type of damage, single strand breaks (SSBs), double-strand breaks (DSBs), base lesions and non-DSB clusters was measured after irradiations in solutions with varying scavenging capacity containing 2-amino-2-(hydroxymethyl)propane-1,3-diol (Tris) and coumarin-3-carboxylic acid (C3CA) as scavengers. Our combined results reveal the determining role of LET and Reactive Oxygen Species (ROS) in DNA fragmentation. Furthermore, AFM used to measure apparent DNA lengths provided us with insights into the role of increasing LET in the induction of highly complex DNA damage.

Downhill running induced DNA damage enhances mitochondrial membrane permeability by facilitating ER-mitochondria signaling

To observe whether downhill running can lead to DNA damage in skeletal muscle cells and changes in mitochondrial membrane permeability and to explore whether the DNA damage caused by downhill running can lead to changes in mitochondrial membrane permeability by regulating the components of the endoplasmic reticulum mitochondrial coupling structure (MAM). A total of 48 male adult Sprague-Dawley rats were randomly divided into a control group (C, n = 8) and a motor group (E, n = 40). Rats in Group E were further divided into 0 h (E0), 12 h (E12), 24 h (E24), 48 h (E48) and 72 h (E72) after prescribed exercise, with 8 rats in each group. At each time point, flounder muscle was collected under general anaesthesia. The DNA oxidative damage marker 8-hydroxydeoxyguanosine (8-OHdG) was detected by immunofluorescence. The expression levels of the DNA damage-related protein p53 in the nucleus and the EI24 protein and reep1 protein in whole cells were detected by Western blot. The colocalization coefficients of the endoplasmic reticulum protein EI24 and the mitochondrial protein Vdac2 were determined by immunofluorescence double staining, and the concentration of Ca²⁺ in skeletal muscle mitochondria was detected by a fluorescent probe. Finally, the opening of the mitochondrial membrane permeability transition pore (mPTP) was detected by immunofluorescence. Twelve hours after downhill running, the mitochondrial membrane permeability of the mPTP opened the most (P < 0.05), the content of 8-OHdG in skeletal muscle peaked (P < 0.05), and the levels of the regulatory protein p53, mitochondrial Ca²⁺, and the EI24 and reep1 proteins peaked (P < 0.01). Moreover, the colocalization coefficients of EI24 and Vdac2 and the Mandes coefficients of the two proteins increased first and then recovered 72 h after exercise (P < 0.05). (1) Downhill running can lead to DNA damage in skeletal muscle cells, overload of mitochondrial Ca²⁺ and large opening of membrane permeability transformation pores. (2) The DNA damage caused by downhill running may result in p53 promoting the transcriptional activation of reep1 and EI24, enhancing the interaction between EI24 and Vdac2, and then leading to an increase in Ca²⁺ in skeletal muscle mitochondria and the opening of membrane permeability transition pores.

Development of an Adverse Outcome Pathway for radiation-induced microcephaly via expert consultation and machine learning

BACKGROUND

Brain development during embryogenesis and in early postnatal life is particularly complex and involves the interplay of many cellular processes and molecular mechanisms, making it extremely vulnerable to exogenous insults, including ionizing radiation (IR). Microcephaly is one of the most frequent neurodevelopmental abnormalities that is characterized by small brain size, and is often associated with intellectual deficiency. Decades of research span from epidemiological data on in utero exposure of the A-bomb survivors, to studies on animal and cellular models that allowed deciphering the most prominent molecular mechanisms leading to microcephaly. The Adverse Outcome Pathway (AOP) framework is used to organize, evaluate and portray the scientific knowledge of toxicological effects spanning different biological levels of organizations, from the initial interaction with molecular targets to the occurrence of a disease or adversity. In the present study, the framework was used in an attempt to organize the current scientific knowledge on microcephaly progression in the context of ionizing radiation (IR) exposure. This work was performed by a group of experts formed during a recent workshop organized jointly by the Multidisciplinary European Low Dose Initiative (MELODI) and the European Radioecology Alliance (ALLIANCE) associations to present the AOP approach and tools. Here we report on the development of a putative AOP for congenital microcephaly resulting from IR exposure based on discussions of the working group and we emphasize the use of a novel machine-learning approach to assist in the screening of the available literature to develop AOPs.

CONCLUSION

The expert consultation led to the identification of crucial biological events for the progression of microcephaly upon exposure to IR, and highlighted current knowledge gaps. The machine learning approach was successfully used to screen the existing knowledge and helped to rapidly screen the body of evidence and in particular the epidemiological data. This systematic review approach also ensured that the analysis was sufficiently comprehensive to identify the most relevant data and facilitate rapid and consistent AOP development. We anticipate that as machine learning approaches become more user-friendly through easy-to-use web interface, this would allow AOP development to become more efficient and less time consuming.

Worenine Prevents Solar Ultraviolet–Induced Sunburn by Inhibiting JNK2

Excessive solar ultraviolet (SUV) radiation often causes dermatitis, photoaging, and even skin cancer. In the pathological processes of SUV-induced sunburn, JNK is activated by phosphorylation, and it in turn phosphorylates its downstream transcription factors, such as ATF2 and c-jun. The transcription factors further regulate the expression of pro-inflammatory genes, such as IL-6 and TNF-α, which ultimately leads to dermatitis. Therefore, inhibiting JNK may be a strategy to prevent dermatitis. In this study, we screened for worenine as a potential drug candidate for inhibiting sunburn. We determined that worenine inhibited the JNK-ATF2/c-jun signaling pathway and the secretion of IL-6 and TNF-α in cell culture and in vivo, confirming the role of worenine in inhibiting sunburn. Furthermore, we determined that worenine bound and inhibited JNK2 activity in vitro through the MST, kinase, and in vitro kinase assays. Therefore, worenine might be a promising drug candidate for the prevention and treatment of SUV-induced sunburn.

Reactive oxygen species accumulation is synchronised with growth inhibition of temperature-sensitive recAts polA Escherichia coli

When combined with recombinase defects, chromosome breakage and double-strand break repair deficiencies render cells inviable. However, cells are viable when an SOS response occurs in recAts polA cells in Escherichia coli. Here, we aimed to elucidate the underlying mechanisms of this process. Transposon mutagenesis revealed that the hslO gene, a redox chaperone Hsp33 involved in reactive oxidative species (ROS) metabolism, was required for the suppression of recAts polA lethality at a restricted temperature. Recently, it has been reported that lethal treatments trigger ROS accumulation. We also found that recAts polA cells accumulated ROS at the restricted temperature. A catalase addition to the medium alleviates the temperature sensitivity of recAts polA cells and decreases ROS accumulation. These results suggest that the SOS response and hslO manage oxidative insult to an acceptable level in cells with oxidative damage and rescue cell growth. Overall, ROS might regulate several cellular processes.

The “End Life” of the Grape Pomace Waste Become the New Beginning: The Development of a Virtuous Cycle for the Green Synthesis of Gold Nanoparticles and Removal of Emerging Contaminants from Water

During the last decades, the demand for processes developed according to the Circular Economy Principles has increased, searching for an alternative life for wastes. For this purpose, a one-pot green approach is exploited during this work to synthesize gold nanoparticles (AuNPs) by using grape pomace waste from Vitis vinifera. A raw aqueous extract of grape seeds, skin, and stems is used for AuNPs synthesis. UV-Vis, XPS, SEM, and ATR-FTIR spectroscopies demonstrate the main role of the extract’s polyphenolic components in stabilizing nanoparticles. XRD, DLS, and Zeta Potential analyses were used to characterize AuNPs. Moreover, the ionic strength, pH, and temperature role was investigated through the Surface Plasmon Resonance (SPR) band observation to assess AuNPs’ stability and photostability. For foreseeing the as-synthesized AuNPs’ potential use in cosmetic and biomedical fields as multifunctional platforms, their antioxidant, and skin-lightening properties were tested, together with their sunscreen ability. A preliminary in-vitro evaluation is reported about the AuNPs’ cytoprotective effects against H₂O₂ oxidative stress-induced in normal human dermal fibroblasts. Briefly, the possibility of reusing the grape pomace waste after the AuNPs synthesis as an adsorbent for the efficient removal of emergent contaminants is preliminarily discussed in the paper, further valorizing the use of waste according to a bio circular approach.

Recent Approaches to Determine Static and Dynamic Redox State-Related Parameters

Oxidative stress refers to an imbalance between oxidant and antioxidant molecules, which is usually associated with oxidative damage to biomolecules and mitochondrial malfunction. Redox state-related parameters include (1) the direct measurement of ROS, (2) the assessment of the antioxidant defense status, and (3) the analysis of the resulting oxidative damage to molecules. Directly measuring ROS appears to be the preferred method among scientists, but most ROS are extremely unstable and difficult to measure. The processes of determining both the oxidative damage to biomolecules and the antioxidant system status, although both are indirect approaches, provide a reliable method to measure oxidative stress on a given sample. Recently, the Seahorse XF and the Oroboros O2k systems have provided new insights into the redox state from a more dynamic point of view. These techniques assess mitochondrial oxidative phosphorylation function and bioenergetics on isolated mitochondria, cultured cells, or specific tissues such as permeabilized fibers. This review describes a range of methodologies to measure redox state-related parameters, their strengths, and their limitations. In conclusion, all these techniques are valid and none of them can be replaced by another. Indeed, they have the potential to complement each other for a complete evaluation of the redox state of a given sample.

DNA Double-Strand Breaks as Pathogenic Lesions in Neurological Disorders

The damage and repair of DNA is a continuous process required to maintain genomic integrity. DNA double-strand breaks (DSBs) are the most lethal type of DNA damage and require timely repair by dedicated machinery. DSB repair is uniquely important to nondividing, post-mitotic cells of the central nervous system (CNS). These long-lived cells must rely on the intact genome for a lifetime while maintaining high metabolic activity. When these mechanisms fail, the loss of certain neuronal populations upset delicate neural networks required for higher cognition and disrupt vital motor functions. Mammalian cells engage with several different strategies to recognize and repair chromosomal DSBs based on the cellular context and cell cycle phase, including homologous recombination (HR)/homology-directed repair (HDR), microhomology-mediated end-joining (MMEJ), and the classic non-homologous end-joining (NHEJ). In addition to these repair pathways, a growing body of evidence has emphasized the importance of DNA damage response (DDR) signaling, and the involvement of heterogeneous nuclear ribonucleoprotein (hnRNP) family proteins in the repair of neuronal DSBs, many of which are linked to age-associated neurological disorders. In this review, we describe contemporary research characterizing the mechanistic roles of these non-canonical proteins in neuronal DSB repair, as well as their contributions to the etiopathogenesis of selected common neurological diseases.

Effects of spawning stress on the immune capacity of blood cockle Tegillarca granosa occurring on the south coast of Korea

Spawning in marine bivalves is a great energy-demanding process, and it often results in lethal and sublethal stresses during the post-spawning period, including depressed immune capacity. The blood cockle Tegillarca granosa (Linnaeus, 1758) distributes widely in silty-mud tidal flats on the south coast of Korea, and they spawn in late summer. To understand the impacts of spawning on immune parameters, we analyzed the total hemocyte count (THC), hemocyte mortality, phagocytosis capacity, and reactive oxygen species (ROS) production of T. granosa in pre-, and post-spawning condition using a flow cytometer. Histology indicated that the blood cockles occurring on the south coast of Korea ripe and ready to spawn in July, and they spawned in August and September. The THC in the blood cockle hemolymph declined from pre-spawning (1.2 × 10⁸ cell mL^-1) to post-spawning (0.9 × 10⁸ cell mL^-1), possibly due to the spawning stress and the massive infiltration of hemocytes in the gonad to phagocytose and resorb the residual gametes during the post-spawning period. The hemocyte mortality increased linearly from August (4.1%) to November (9.1%), as the histology revealed that the blood cockle completed spawning, and they resorbed the relict gametes. The granulocyte phagocytosis capacity declined dramatically from July (12.7%) to September (6.0%), when the cockles were engaged in active spawning. The flow cytometry revealed that the production of reactive oxygen species (ROS) from the granulocytes and the erythrocytes type II increased linearly from August (0.8-0.9 × 10⁵ A U.) to December (2.1-2.8 × 10⁵ A U.), which may cause stresses at a cellular level during this period. As the data indicated, spawning is a stressful activity inducing depressed immunological capacities in the blood cockles.

The Use of ProteoTuner Technology to Study Nuclear Factor κB Activation by Heavy Ions

Nuclear factor κB (NF-κB) activation might be central to heavy ion-induced detrimental processes such as cancer promotion and progression and sustained inflammatory responses. A sensitive detection system is crucial to better understand its involvement in these processes. Therefore, a DD-tdTomato fluorescent protein-based reporter system was previously constructed with human embryonic kidney (HEK) cells expressing DD-tdTomato as a reporter under the control of a promoter containing NF-κB binding sites (HEK-pNFκB-DD-tdTomato-C8). Using this reporter cell line, NF-κB activation after exposure to different energetic heavy ions (¹⁶O, 95 MeV/n, linear energy transfer—LET 51 keV/µm; ¹²C, 95 MeV/n, LET 73 keV/μm; ³⁶Ar, 95 MeV/n, LET 272 keV/µm) was quantified considering the dose and number of heavy ions hits per cell nucleus that double NF-κB-dependent DD-tdTomato expression. Approximately 44 hits of ¹⁶O ions and ≈45 hits of ¹²C ions per cell nucleus were required to double the NF-κB-dependent DD-tdTomato expression, whereas only ≈3 hits of ³⁶Ar ions were sufficient. In the presence of Shield-1, a synthetic molecule that stabilizes DD-tdTomato, even a single particle hit of ³⁶Ar ions doubled NF-κB-dependent DD-tdTomato expression. In conclusion, stabilization of the reporter protein can increase the sensitivity for NF-κB activation detection by a factor of three, allowing the detection of single particle hits’ effects.

Primary Vestibular Schwannoma Cells Activate p21 and RAD51-Associated DNA Repair Following Radiation-Induced DNA Damage

HYPOTHESIS

Vestibular Schwannoma (VS) can avoid cell death following radiation injury by entering cell cycle arrest and activating RAD51-related DNA repair.

BACKGROUND

Although the radiobiology of various cancers is well-studied, the radiobiological effects in VS are poorly understood. In this study, we describe how VS cells enter cell cycle arrest (through p21 expression), activate DNA repair (through RAD51 upregulation), and avoid cell death after radiation-induced double-stranded breaks (DSB) in DNA (as measured by γ-H2AX).

METHODS

Primary human VS cells were cultured on 96-well plates and 16-well culture slides at 10,000 cells/well and exposed to either 0 or 18 Gray of radiation. Viability assays were performed at 96 h in vitro. Immunofluorescence for γ-H2AX, RAD51, and p21 was performed at 6 h.

RESULTS

Radiation (18 Gy) induced the expression of γ-H2AX, p21, and RAD51 in six cultured VS, suggesting that irradiated VS acquire DSBs, enter cell cycle arrest, and initiate RAD51 DNA repair to evade cell death. However, viability studies demonstrate variable responses in individual VS cells with 3 of 6 VS showing radiation resistance to 18 Gy. On further analyses, radiation-resistant VS cells expressed significantly more p21 than radiation-responsive tumors.

CONCLUSIONS

In response to radiation-induced DNA damage, primary VS cells can enter cell cycle arrest and express RAD51 DNA repair mechanisms to avoid cell death. Radioresistant VS cells may mount a more robust p21 response to ensure sufficient time for DNA repair. Further investigation into DNA repair proteins and cell cycle checkpoints may provide important insight on the radiobiology of VS and mechanisms for resistance.

Bioactivity of PEGylated Graphene Oxide Nanoparticles Combined with Near-Infrared Laser Irradiation Studied in Colorectal Carcinoma Cells

Central focus in modern anticancer nanosystems is given to certain types of nanomaterials such as graphene oxide (GO). Its functionalization with polyethylene glycol (PEG) demonstrates high delivery efficiency and controllable release of proteins, bioimaging agents, chemotherapeutics and anticancer drugs. GO-PEG has a good biological safety profile, exhibits high NIR absorbance and capacity in photothermal treatment. To investigate the bioactivity of PEGylated GO NPs in combination with NIR irradiation on colorectal cancer cells we conducted experiments that aim to reveal the molecular mechanisms of action of this nanocarrier, combined with near-infrared light (NIR) on the high invasive Colon26 and the low invasive HT29 colon cancer cell lines. During reaching cancer cells the phototoxicity of GO-PEG is modulated by NIR laser irradiation. We observed that PEGylation of GO nanoparticles has well-pronounced biocompatibility toward colorectal carcinoma cells, besides their different malignant potential and treatment times. This biocompatibility is potentiated when GO-PEG treatment is combined with NIR irradiation, especially for cells cultured and treated for 24 h. The tested bioactivity of GO-PEG in combination with NIR irradiation induced little to no damages in DNA and did not influence the mitochondrial activity. Our findings demonstrate the potential of GO-PEG-based photoactivity as a nanosystem for colorectal cancer treatment.

Bile reflux and hypopharyngeal cancer (Review)

Laryngopharyngeal reflux, a variant of gastroesophageal reflux disease, has been considered a risk factor in the development of hypopharyngeal cancer. Bile acids are frequently present in the gastroesophageal refluxate and their effect has been associated with inflammatory and neoplastic changes in the upper aerodigestive tract. Recent in vitro and in vivo studies have provided direct evidence of the role of acidic bile refluxate in hypopharyngeal carcinogenesis and documented the crucial role of NF-κB as a key mediator of early oncogenic molecular events in this process and also suggested a contribution of STAT3. Acidic bile can cause premalignant changes and invasive squamous cell cancer in the affected hypopharynx accompanied by DNA damage, elevated p53 expression and oncogenic mRNA and microRNA alterations, previously linked to head and neck cancer. Weakly acidic bile can also increase the risk for hypopharyngeal carcinogenesis by inducing DNA damage, exerting anti-apoptotic effects and causing precancerous lesions. The most important findings that strongly support bile reflux as an independent risk factor for hypopharyngeal cancer are presented in the current review and the underlying mechanisms are provided.

Low Dose Ionising Radiation-Induced Hormesis: Therapeutic Implications to Human Health

The concept of radiation-induced hormesis, whereby a low dose is beneficial and a high dose is detrimental, has been gaining attention in the fields of molecular biology, environmental toxicology and radiation biology. There is a growing body of literature that recognises the importance of hormetic dose response not only in the radiation field, but also with molecular agents. However, there is continuing debate on the magnitude and mechanism of radiation hormetic dose response, which could make further contributions, as a research tool, to science and perhaps eventually to public health due to potential therapeutic benefits for society. The biological phenomena of low dose ionising radiation (LDIR) includes bystander effects, adaptive response, hypersensitivity, radioresistance and genomic instability. In this review, the beneficial and the detrimental effects of LDIR-induced hormesis are explored, together with an overview of its underlying cellular and molecular mechanisms that may potentially provide an insight to the therapeutic implications to human health in the future.

Understanding the Radiobiology of Vestibular Schwannomas to Overcome Radiation Resistance

Vestibular schwannomas (VS) are benign tumors arising from cranial nerve VIII that account for 8-10% of all intracranial tumors and are the most common tumors of the cerebellopontine angle. These tumors are typically managed with observation, radiation therapy, or microsurgical resection. Of the VS that are irradiated, there is a subset of tumors that are radioresistant and continue to grow; the mechanisms behind this phenomenon are not fully understood. In this review, the authors summarize how radiation causes cellular and DNA injury that can activate (1) checkpoints in the cell cycle to initiate cell cycle arrest and DNA repair and (2) key events that lead to cell death. In addition, we discuss the current knowledge of VS radiobiology and how it may contribute to clinical outcomes. A better understanding of VS radiobiology can help optimize existing treatment protocols and lead to new therapies to overcome radioresistance.

Radiobiological risks following dentomaxillofacial imaging: should we be concerned?

OBJECTIVES

This review aimed to present studies that prospectively investigated biological effects in patients following diagnostic dentomaxillofacial radiology (DMFR).

METHODS

Literature was systematically searched to retrieve all studies assessing radiobiological effects of using X-ray imaging in the dentomaxillofacial area, with reference to radiobiological outcomes for other imaging modalities and fields.

RESULTS

There is a lot of variability in the reported radiobiological assessment methods and radiation dose measures, making comparisons of radiobiological studies challenging. Most radiological DMFR studies are focusing on genotoxicity and cytotoxicity, data for 2D dentomaxillofacial radiographs, albeit with some methodological weakness biasing the results. For CBCT, available evidence is limited and few studies include comparative data on both adults and children.

CONCLUSIONS

In the future, one will have to strive towards patient-specific measures by considering age, gender and other individual radiation sensitivity-related factors. Ultimately, future radioprotection strategies should build further on the concept of personalized medicine, with patient-specific optimization of the imaging protocol, based on radiobiological variables.

The Role of DNA Damage Response in Dysbiosis-Induced Colorectal Cancer

The high incidence of colorectal cancer (CRC) in developed countries indicates a predominant role of the environment as a causative factor. Natural gut microbiota provides multiple benefits to humans. Dysbiosis is characterized by an unbalanced microbiota and causes intestinal damage and inflammation. The latter is a common denominator in many cancers including CRC. Indeed, in an inflammation scenario, cellular growth is promoted and immune cells release Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS), which cause DNA damage. Apart from that, many metabolites from the diet are converted into DNA damaging agents by microbiota and some bacteria deliver DNA damaging toxins in dysbiosis conditions as well. The interactions between diet, microbiota, inflammation, and CRC are not the result of a straightforward relationship, but rather a network of multifactorial interactions that deserve deep consideration, as their consequences are not yet fully elucidated. In this paper, we will review the influence of dysbiosis in the induction of DNA damage and CRC.

Radiation-Induced Effect on Spin-Selective Electron Transfer through Self-Assembled Monolayers of ds-DNA

Stability of the DNA molecule is essential for the proper functioning and sustainability of all living organisms. In this study, we investigate the effect of gamma radiation (γ-radiation) on spin-selective electron transfer through double strand (ds)DNA molecules. Self-assembled monolayers (SAMs) of 21-base long DNA are prepared on Au-coated Ni thin film. We measure the spin polarization (%) of the SAMs of ds-DNA using the spin-dependent electrochemical technique. We use a Cs-based γ-radiation source to expose the SAMs of ds-DNA immobilized on thin films for various time intervals ranging from 0–30 min. The susceptibility of DNA to γ-radiation is measured by spin-dependent electrochemistry. We observe that the efficiency of spin filtering by ds-DNA gradually decreases when exposure (to γ-radiation) time increases, and drops below 1% after 30 min of exposure. The change in spin polarization value is related either to the conformational perturbation in DNA or to structural damage in DNA molecules caused by ionizing radiation.

A Dynamic View of the Interaction of Histone Tails with Clustered Abasic Sites in a Nucleosome Core Particle

Apurinic/apyrimidinic sites are the most common forms of DNA damage under physiological conditions, yet their structural and dynamical behavior within nucleosome core particles has just begun to be investigated and is dramatically different from that of abasic sites in B-DNA. Clusters of two or more abasic sites are repaired even less efficiently and hence constitute hot spots of high mutagenicity notably due to enhanced double-strand break formation. On the basis of an X-ray structure of a 146 bp DNA wrapped onto a histone core, we investigate the structural behavior of two bistranded abasic sites positioned at mutational hot spots during microsecond-range molecular dynamics simulations. Our simulations allow us to probe interactions of histone tails at clustered abasic site locations, with a definitive assignment of the key residues involved in the NCP-catalyzed formation of DNA-protein cross-linking in line with recent experimental findings, and pave the way for a systematic assessment of the response of histone tails to DNA lesions.

Mechanistic Biomarkers in Toxicology

Biomarkers are important parameters that are reliable, applicable, reproducible, and generally inexpensive. All biomarkers have a significant role in human health, especially mechanistic biomarkers, which are the most important for the prevention of toxic effects and diseases. They demonstrate the possibility of diagnosis, prognosis, recurrence, and spread of disease. Furthermore, they show the exposure levels to numerous chemical, biological, and physical agents. To date, the development and application of biomarkers require the knowledge of mechanisms underlying their production. Therefore, the present study focused on the possible mechanistic biomarkers.

Evolution of core archetypal phenotypes in progressive high grade serous ovarian cancer

The evolution of resistance in high-grade serous ovarian cancer (HGSOC) cells following chemotherapy is only partially understood. To understand the selection of factors driving heterogeneity before and through adaptation to treatment, we profile single-cell RNA-sequencing (scRNA-seq) transcriptomes of HGSOC tumors collected longitudinally during therapy. We analyze scRNA-seq data from two independent patient cohorts to reveal that HGSOC is driven by three archetypal phenotypes, defined as oncogenic states that describe the majority of the transcriptome variation. Using a multi-task learning approach to identify the biological tasks of each archetype, we identify metabolism and proliferation, cellular defense response, and DNA repair signaling as consistent cell states found across patients. Our analysis demonstrates a shift in favor of the metabolism and proliferation archetype versus cellular defense response archetype in cancer cells that received multiple lines of treatment. While archetypes are not consistently associated with specific whole-genome driver mutations, they are closely associated with subclonal populations at the single-cell level, indicating that subclones within a tumor often specialize in unique biological tasks. Our study reveals the core archetypes found in progressive HGSOC and shows consistent enrichment of subclones with the metabolism and proliferation archetype as resistance is acquired to multiple lines of therapy.

Association between Food Intake, Clinical and Metabolic Markers and DNA Damage in Older Subjects

The use of DNA damage as marker of oxidative stress, metabolic dysfunction and age-related diseases is debated. The present study aimed at assessing the level of DNA damage (evaluated as DNA strand-breaks, endogenous and oxidatively-induced DNA damage) in a group of older subjects with intestinal permeability enrolled within the MaPLE (Gut and Blood Microbiomics for Studying the Effect of a Polyphenol-Rich Dietary Pattern on Intestinal Permeability in the Elderly) intervention trial, to evaluate its association with clinical, metabolic and dietary markers. DNA damage in peripheral blood mononuclear cells was assessed by the comet assay in 49 older subjects participating in the study. Clinical and metabolic markers, markers of inflammation, vascular function and intestinal permeability were determined in serum. Food intake was estimated by weighted food diaries. On the whole, a trend towards higher levels of DNA damage was observed in men compared to women (p = 0.071). A positive association between DNA damage and clinical/metabolic markers (e.g., uric acid, lipid profile) and an inverse association with dietary markers (e.g., vitamin C, E, B₆, folates) were found and differed based on sex. By considering the importance of DNA stability during aging, the results obtained on sex differences and the potential role of dietary and metabolic factors on DNA damage underline the need for further investigations in a larger group of older adults to confirm the associations found and to promote preventive strategies.

Common and Novel Markers for Measuring Inflammation and Oxidative Stress Ex Vivo in Research and Clinical Practice-Which to Use Regarding Disease Outcomes?

Many chronic conditions such as cancer, chronic obstructive pulmonary disease, type-2 diabetes, obesity, peripheral/coronary artery disease and auto-immune diseases are associated with low-grade inflammation. Closely related to inflammation is oxidative stress (OS), which can be either causal or secondary to inflammation. While a low level of OS is physiological, chronically increased OS is deleterious. Therefore, valid biomarkers of these signalling pathways may enable detection and following progression of OS/inflammation as well as to evaluate treatment efficacy. Such biomarkers should be stable and obtainable through non-invasive methods and their determination should be affordable and easy. The most frequently used inflammatory markers include acute-phase proteins, essentially CRP, serum amyloid A, fibrinogen and procalcitonin, and cytokines, predominantly TNFα, interleukins 1β, 6, 8, 10 and 12 and their receptors and IFNγ. Some cytokines appear to be disease-specific. Conversely, OS-being ubiquitous-and its biomarkers appear less disease or tissue-specific. These include lipid peroxidation products, e.g., F2-isoprostanes and malondialdehyde, DNA breakdown products (e.g., 8-OH-dG), protein adducts (e.g., carbonylated proteins), or antioxidant status. More novel markers include also -omics related ones, as well as non-invasive, questionnaire-based measures, such as the dietary inflammatory-index (DII), but their link to biological responses may be variable. Nevertheless, many of these markers have been clearly related to a number of diseases. However, their use in clinical practice is often limited, due to lacking analytical or clinical validation, or technical challenges. In this review, we strive to highlight frequently employed and useful markers of inflammation-related OS, including novel promising markers.

Using Machine Learning Techniques for Asserting Cellular Damage Induced by High-LET Particle Radiation

This is a study concerning the use of Machine Learning (ML) techniques to ascertain the impacts of particle ionizing radiation (IR) on cell survival and DNA damage. Current empirical models do not always take into account intrinsic complexities and stochastic effects of the interactions of IR and cell populations. Furthermore, these models often lack in biophysical interpretations of the irradiation outcomes. The linear quadratic (LQ) model is a common way to associate the biological response of a cell population with the radiation dose. The parameters of the LQ model are used to extrapolate the relation between the dosage and the survival fraction of a cell population. The goal was to create a ML-based model that predicts the α and β parameters of the well known and established LQ model, along with the key metrics of DNA damage induction. The main target of this effort was, on the one hand, the development of a computational framework that will be able to assess key radiobiophysical quantities, and on the other hand, to provide meaningful interpretations of the outputs. Based on our results, as some metrics of the adaptability and training efficiency, our ML models exhibited 0.18 median error (relative root mean squared error (RRMSE)) in the prediction of the α parameter and errors of less than 0.01 for various DNA damage quantities; the prediction for β exhibited a rather large error of 0.75. Our study is based on experimental data from a publicly available dataset of irradiation studies. All types of complex DNA damage (all clusters), and the number of double-stranded breaks (DSBs), which are widely accepted to be closely related to cell survival and the detrimental biological effects of IR, were calculated using the fast Monte Carlo Damage Simulation software (MCDS). We critically discussed the varying importance of physical parameters such as charge and linear energy transfer (LET); we also discussed the uncertainties of our predictions and future directions, and the dynamics of our approach.

A Meta-Analysis of the Effects of High-LET Ionizing Radiations in Human Gene Expression

The use of high linear energy transfer (LET) ionizing radiation (IR) is progressively being incorporated in radiation therapy due to its precise dose localization and high relative biological effectiveness. At the same time, these benefits of particle radiation become a high risk for astronauts in the case of inevitable cosmic radiation exposure. Nonetheless, DNA Damage Response (DDR) activated via complex DNA damage in healthy tissue, occurring from such types of radiation, may be instrumental in the induction of various chronic and late effects. An approach to elucidating the possible underlying mechanisms is studying alterations in gene expression. To this end, we identified differentially expressed genes (DEGs) in high Z and high energy (HZE) particle-, γ-ray- and X-ray-exposed healthy human tissues, utilizing microarray data available in public repositories. Differential gene expression analysis (DGEA) was conducted using the R programming language. Consequently, four separate meta-analyses were conducted, after DEG lists were grouped depending on radiation type, radiation dose and time of collection post-irradiation. To highlight the biological background of each meta-analysis group, functional enrichment analysis and biological network construction were conducted. For HZE particle exposure at 8–24 h post-irradiation, the most interesting finding is the variety of DNA repair mechanisms that were downregulated, a fact that is probably correlated with complex DNA damage formation. Simultaneously, after X-ray exposure during the same hours after irradiation, DNA repair mechanisms continue to take place. Finally, in a further comparison of low- and high-LET radiation effects, the most prominent result is that autophagy mechanisms seem to persist and that adaptive immune induction seems to be present. Such bioinformatics approaches may aid in obtaining an overview of the cellular response to high-LET particles. Understanding these response mechanisms can consequently aid in the development of countermeasures for future space missions and ameliorate heavy ion treatments.

Ionizing radiation-induced genotoxic and oxidative damage in peripheral lymphocytes and plasma of healthy donors

Biological dosimetry of ionizing radiation (IR) exposure relies on validated cytogenetic tests measuring the frequencies of micronuclei (MN) and dicentric chromosomes (DC). IR also causes oxidative damage of biomolecules, including DNA. We evaluated IR-induced genotoxic and oxidative damage in a carefully defined cohort of healthy donors, reducing confounding factors as much as possible. Frequencies of MN and DC (peripheral blood lymphocyte cultures) and oxidative stress parameters (plasma) were quantified. We observed dose dependence of both cytogenetic and biochemical endpoints, independent of age, sex, and smoking habits. Oxidative stress parameters, especially oxidative stress index, malondialdehyde, advanced oxidation protein products, and catalase, may be used confidently to assess IR-induced damage, if cytogenetic results are unavailable.

In Situ Detection of Complex DNA Damage Using Microscopy: A Rough Road Ahead

Complexity of DNA damage is considered currently one if not the primary instigator of biological responses and determinant of short and long-term effects in organisms and their offspring. In this review, we focus on the detection of complex (clustered) DNA damage (CDD) induced for example by ionizing radiation (IR) and in some cases by high oxidative stress. We perform a short historical perspective in the field, emphasizing the microscopy-based techniques and methodologies for the detection of CDD at the cellular level. We extend this analysis on the pertaining methodology of surrogate protein markers of CDD (foci) colocalization and provide a unique synthesis of imaging parameters, software, and different types of microscopy used. Last but not least, we critically discuss the main advances and necessary future direction for the better detection of CDD, with important outcomes in biological and clinical setups.

Antimycin A shows selective antiproliferation to oral cancer cells by oxidative stress-mediated apoptosis and DNA damage

The antibiotic antimycin A (AMA) is commonly used as an inhibitor for the electron transport chain but its application in anticancer studies is rare. Recently, the repurposing use of AMA in antiproliferation of several cancer cell types has been reported. However, it is rarely investigated in oral cancer cells. The purpose of this study is to investigate the selective antiproliferation ability of AMA treatment on oral cancer cells. Cell viability, flow cytometry, and western blotting were applied to explore its possible anticancer mechanism in terms of both concentration- and exposure time-effects. AMA shows the higher antiproliferation to two oral cancer CAL 27 and Ca9-22 cell lines than normal oral HGF-1 cell lines. Moreover, AMA induces the production of higher reactive oxygen species (ROS) levels and pan-caspase activation in oral cancer CAL 27 and Ca9-22 cells than in normal oral HGF-1 cells, providing the possible mechanism for its selective antiproliferation effect of AMA. In addition to ROS, AMA induces mitochondrial superoxide (MitoSOX) generation and depletes mitochondrial membrane potential (MitoMP). This further supports the AMA-induced oxidative stress changes in oral cancer CAL 27 and Ca9-22 cells. AMA also shows high expressions of annexin V in CAL 27 and Ca9-22 cells and cleaved forms of poly (ADP-ribose) polymerase (PARP), caspase 9, and caspase 3 in CAL 27 cells, supporting the apoptosis-inducing ability of AMA. Furthermore, AMA induces DNA damage (γH2AX and 8-oxo-2'-deoxyguanosine [8-oxodG]) in CAL 27 and Ca9-22 cells. Notably, the AMA-induced selective antiproliferation, oxidative stress, and DNA damage were partly prevented from N-acetylcysteine (NAC) pretreatments. Taken together, AMA selectively kills oral cancer cells in an oxidative stress-dependent mechanism involving apoptosis and DNA damage.

8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a Cause of Autoimmune Thyroid Diseases (AITD) During Pregnancy?

The thyroid is not necessary to sustain life. However, thyroid hormones (TH) strongly affect the human body. Functioning of the thyroid gland affects the reproductive capabilities of women and men, as well as fertilization and maintaining a pregnancy. For the synthesis of TH, hydrogen peroxide (H₂O₂) is necessary. From the chemical point of view, TH is a reactive oxygen species (ROS) and serves as an oxidative stress (OS) promoter. H₂O₂ concentration in the thyroid gland is much higher than in other tissues. Therefore, the thyroid is highly exposed to OS. 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) are DNA lesions resulting from ROS action onto guanine moiety. Due to their abundance, they are recognized as biomarkers of OS. As thyroid function is correlated with the level of OS, 8-oxodG and 8-OHdG has been taken under consideration. Studies correlate the oxidative DNA damage with various thyroid diseases (TD) such as Hashimoto's thyroiditis (HT), Graves' disease (GD), and thyroid cancer. Human sexual function and fertility are also affected by OS and TD. Hypothyroidism and hyperthyroidism diagnosed in pregnant women have a negative effect on pregnancy as it may increase the risk of miscarriage or fetus mortality. In the case of TD in the mother, fetal health is also at risk - neurodevelopment and cognitive function of the child may be impaired in its future life. This review presents thyroid function in the context of TD during pregnancy. The authors introduce OS and describe oxidative DNA lesions as a crucial marker of thyroid pathologies.

Role of DNA damage and repair in radiation cancer therapy: a current update and a look to the future

Radiation Therapy (RT), a widely used modality against cancer, depends its effectiveness on three pillars: tumor targeting precision, minimum dose determination and co-administrated agents. The underlying biological processes of the latter two pillars are DNA damage and repair. Hopefully, Radiation treatment has nowadays been improved a lot, in terms of tumor targeting precision as well as in minimization of side effects, by reducing normal tissue radiation exposure and therefore its occurred toxicity. Normal tissue toxicity is a major risk factor for induction of genomic instability which may lead to secondary cancer development, due to the radiation therapy itself. We discuss, in this review, the biological significance of IR-induced complex DNA damage, which is currently accepted as the definite regulator of biological response to radiation, as well as the regulator of the implications of this IR signature in radiation therapy. We unite accumulating evidence and knowledge over the last 20 years or so on the importance of radiation treatment of cancer. This radiation-based therapy comes unfortunately with a deficit and this is the radiation-induced genetic instability which can fuel radiation toxicity, even several years after the initial treatment on patients through the activation of DNA damage response (DDR) and the immune system.

Spontaneous and Radiation-Induced Chromosome Aberrations in Primary Fibroblasts of Patients With Pediatric First and Second Neoplasms

The purpose of the present study was to investigate whether former childhood cancer patients who developed a subsequent secondary primary neoplasm (SPN) are characterized by elevated spontaneous chromosomal instability or cellular and chromosomal radiation sensitivity as surrogate markers of compromised DNA repair compared to childhood cancer patients with a first primary neoplasm (FPN) only or tumor-free controls. Primary skin fibroblasts were obtained in a nested case-control study including 23 patients with a pediatric FPN, 22 matched patients with a pediatric FPN and an SPN, and 22 matched tumor-free donors. Clonogenic cell survival and cytogenetic aberrations in Giemsa-stained first metaphases were assessed after X-irradiation in G1 or on prematurely condensed chromosomes of cells irradiated and analyzed in G2. Fluorescence in situ hybridization was applied to investigate spontaneous transmissible aberrations in selected donors. No significant difference in clonogenic survival or the average yield of spontaneous or radiation-induced aberrations was found between the study populations. However, two donors with an SPN showed striking spontaneous chromosomal instability occurring as high rates of numerical and structural aberrations or non-clonal and clonal translocations. No correlation was found between radiation sensitivity and a susceptibility to a pediatric FPN or a treatment-associated SPN. Together, the results of this unique case-control study show genomic stability and normal radiation sensitivity in normal somatic cells of donors with an early and high intrinsic or therapy-associated tumor risk. These findings provide valuable information for future studies on the etiology of sporadic childhood cancer and therapy-related SPN as well as for the establishment of predictive biomarkers based on altered DNA repair processes.

Protective effect of the medicinal herb infusion "horchata" against oxidative damage in cigarette smokers: An ex vivo study

Cigarette smoking has been associated with an increase in oxidative stress (OS) and is considered a predisposing factor to chronic noncommunicable diseases, whilst dietary antioxidants has been proposed as an alternative to cope with this oxidative stress. In this study, 20 smokers and 20 non-smokers were studied with the aim of determining their antioxidant status, as well as the ability of an infusion of 23 medicinal plants, to counteract the damage caused by OS. The plasma, red blood cells (RBCs) and polymorphonuclear cells (PBMCs) of both groups were incubated or not with the horchata infusion extract and then the OS markers, genotoxicity, nanostructure of RBCs membrane and genes related to oxidative responses and cellular functionality were evaluated. Up to 33 different compounds, mainly quercetin glycosides, were identified in the extract. A significant deterioration in the antioxidant status in smokers compared to non-smokers was found. The horchata infusion extract improved the nanostructure of RBCs and DNA damage, as well as the activity of the endogenous antioxidant enzymes and markers of oxidative damage to lipid, and proteins in plasma, RBCs and PBMCs in both groups, whilst no significant changes were found in the expression of different genes related to OS response.

The role of the aqueous extract Polypodium leucotomos in photoprotection

Solar radiation in the ultraviolet (UV), visible (VIS), and infrared (IR) ranges produces different biological effects in humans. Most of these, particularly those derived from ultraviolet radiation (UVR) are harmful to the skin, and include cutaneous aging and increased risk of cutaneous diseases, particularly skin cancer. Pharmacological photoprotection is mostly topical, but it can also be systemic. Oral photoprotectives constitute a new generation of drugs to combat the deleterious effects of solar radiation. Among these, an extract of Polypodium leucotomos (PL/Fernblock®, IFC Group, Spain) contains a high content of phenolic compounds that endow it with antioxidant activity. PL can administered orally or topically and is completely safe. PL complements and enhances endogenous antioxidant systems by neutralizing superoxide anions, hydroxyl radicals, and lipoperoxides. In addition to its antioxidant activity, PL also improves DNA repair and modulates immune and inflammatory responses. These activities are likely due to its ability to inhibit the generation and release of reactive oxygen species (ROS) by UVR, VIS, and IR radiation. PL also prevents direct DNA damage by accelerating the removal of induced photoproducts and decreasing UV-induced mutations. Oral PL increases the expression of active p53, decreases cell proliferation, and inhibits UV-induced COX-2 enzyme levels. PL has been used to treat skin diseases such as photodermatoses and pigmentary disorders and recently as a complement of photodynamic phototherapy in actinic keratoses. The photoprotective capability of PL has been proven in a multitude of in vitro and in vivo studies, which include animal models and clinical trials with human subjects. Based on this evidence, PL is a new generation photoprotector with antioxidant and anti-inflammatory properties that also protects DNA integrity and enhances the immune response.

Adverse outcome pathways for ionizing radiation and breast cancer involve direct and indirect DNA damage, oxidative stress, inflammation, genomic instability, and interaction with hormonal regulation of the breast

Knowledge about established breast carcinogens can support improved and modernized toxicological testing methods by identifying key mechanistic events. Ionizing radiation (IR) increases the risk of breast cancer, especially for women and for exposure at younger ages, and evidence overall supports a linear dose-response relationship. We used the Adverse Outcome Pathway (AOP) framework to outline and evaluate the evidence linking ionizing radiation with breast cancer from molecular initiating events to the adverse outcome through intermediate key events, creating a qualitative AOP. We identified key events based on review articles, searched PubMed for recent literature on key events and IR, and identified additional papers using references. We manually curated publications and evaluated data quality. Ionizing radiation directly and indirectly causes DNA damage and increases production of reactive oxygen and nitrogen species (RONS). RONS lead to DNA damage and epigenetic changes leading to mutations and genomic instability (GI). Proliferation amplifies the effects of DNA damage and mutations leading to the AO of breast cancer. Separately, RONS and DNA damage also increase inflammation. Inflammation contributes to direct and indirect effects (effects in cells not directly reached by IR) via positive feedback to RONS and DNA damage, and separately increases proliferation and breast cancer through pro-carcinogenic effects on cells and tissue. For example, gene expression changes alter inflammatory mediators, resulting in improved survival and growth of cancer cells and a more hospitable tissue environment. All of these events overlap at multiple points with events characteristic of "background" induction of breast carcinogenesis, including hormone-responsive proliferation, oxidative activity, and DNA damage. These overlaps make the breast particularly susceptible to ionizing radiation and reinforce that these biological activities are important characteristics of carcinogens. Agents that increase these biological processes should be considered potential breast carcinogens, and predictive methods are needed to identify chemicals that increase these processes. Techniques are available to measure RONS, DNA damage and mutation, cell proliferation, and some inflammatory proteins or processes. Improved assays are needed to measure GI and chronic inflammation, as well as the interaction with hormonally driven development and proliferation. Several methods measure diverse epigenetic changes, but it is not clear which changes are relevant to breast cancer. In addition, most toxicological assays are not conducted in mammary tissue, and so it is a priority to evaluate if results from other tissues are generalizable to breast, or to conduct assays in breast tissue. Developing and applying these assays to identify exposures of concern will facilitate efforts to reduce subsequent breast cancer risk.

Adverse outcome pathways for ionizing radiation and breast cancer involve direct and indirect DNA damage, oxidative stress, inflammation, genomic instability, and interaction with hormonal regulation of the breast

Knowledge about established breast carcinogens can support improved and modernized toxicological testing methods by identifying key mechanistic events. Ionizing radiation (IR) increases the risk of breast cancer, especially for women and for exposure at younger ages, and evidence overall supports a linear dose-response relationship. We used the Adverse Outcome Pathway (AOP) framework to outline and evaluate the evidence linking ionizing radiation with breast cancer from molecular initiating events to the adverse outcome through intermediate key events, creating a qualitative AOP. We identified key events based on review articles, searched PubMed for recent literature on key events and IR, and identified additional papers using references. We manually curated publications and evaluated data quality. Ionizing radiation directly and indirectly causes DNA damage and increases production of reactive oxygen and nitrogen species (RONS). RONS lead to DNA damage and epigenetic changes leading to mutations and genomic instability (GI). Proliferation amplifies the effects of DNA damage and mutations leading to the AO of breast cancer. Separately, RONS and DNA damage also increase inflammation. Inflammation contributes to direct and indirect effects (effects in cells not directly reached by IR) via positive feedback to RONS and DNA damage, and separately increases proliferation and breast cancer through pro-carcinogenic effects on cells and tissue. For example, gene expression changes alter inflammatory mediators, resulting in improved survival and growth of cancer cells and a more hospitable tissue environment. All of these events overlap at multiple points with events characteristic of "background" induction of breast carcinogenesis, including hormone-responsive proliferation, oxidative activity, and DNA damage. These overlaps make the breast particularly susceptible to ionizing radiation and reinforce that these biological activities are important characteristics of carcinogens. Agents that increase these biological processes should be considered potential breast carcinogens, and predictive methods are needed to identify chemicals that increase these processes. Techniques are available to measure RONS, DNA damage and mutation, cell proliferation, and some inflammatory proteins or processes. Improved assays are needed to measure GI and chronic inflammation, as well as the interaction with hormonally driven development and proliferation. Several methods measure diverse epigenetic changes, but it is not clear which changes are relevant to breast cancer. In addition, most toxicological assays are not conducted in mammary tissue, and so it is a priority to evaluate if results from other tissues are generalizable to breast, or to conduct assays in breast tissue. Developing and applying these assays to identify exposures of concern will facilitate efforts to reduce subsequent breast cancer risk.