Biomarker Of DNA Damage Research Articles

Next-Generation Sequencing-Based Analysis of the Roles of DNA Polymerases ν and θ in the Replicative Bypass of 8-Oxo-7,8-dihydroguanine in Human Cells.

DNA polymerase (Pol) ν and Pol θ are two specialized A-family DNA polymerases that function in the translesion synthesis of certain DNA lesions. However, the biological functions of human Pols ν and θ in cellular replicative bypass of 8-oxo-7,8-dihydroguanine (8-oxoG), an important carcinogenesis-related biomarker of oxidative DNA damage, remain unclear. Herein, we showed that depletion of Pols ν and θ in human cells could cause an elevated hypersensitivity to oxidative stress induced by hydrogen peroxide. Using next-generation sequencing-based lesion bypass and mutagenesis assay, we further demonstrated that Pols ν and θ had important roles in promoting translesion synthesis of 8-oxoG in human cells. We also found that the depletion of Pol ν, but not Pol θ, caused a substantial reduction in G → T mutation frequency for 8-oxoG. These findings provided novel insights into the involvement of A-family DNA polymerases in oxidative DNA damage response.

Chromosome length ratio as a biomarker of DNA damage in cells exposed to high dose ionizing radiation

The premature chromosome condensation (PCC) assay is considered as complementary bio-dosimetry tool for chromosome aberration assay and the PCC assay can be used to estimate high dose exposure. Though the PCC ring is considered as prospective biomarker, chromosome length ratio (ratio of longest and shortest chromosome length in PCC spreads) of chemically induced PCC is shown to be very good indicator of ionizing radiation. In view of this, an in-vitro study has been performed using PCC assay to suggest chromosome length ratio (LR) as potential bio-dosimeter induced by high dose ionizing radiation. Blood samples were collected from healthy subjects (n=3) after prior consent and irradiated to ten different doses ranging between 0 and 20Gy using 6MV LINAC X-rays with dose rate of 5.6Gy/min. Irradiated lymphocytes were cultured and calyculin induced PCC spreads were prepared. PCC spreads were captured using image analysis system and chromosome lengths were measured using open-source ImageJ software. For each dose, LR for 50 chromosome spreads were computed and mean LR value was calculated. LR varies between 6.0±0.08 and23.6±0.55 for the dose range between 2 and 20Gy. The dose response curve for LR was observed to be linear with y=1.02x+3.36, R2 =0.97. Linear dose response relationship obtained in the present study confirms the prospective use of LR measurement. This study is first of its kind to examine chromosome length ratio as a biomarker of DNA damage in cells exposed to high dose X-ray exposure.

Persistent γ-H2AX Formation and Expression of Stem Cell Markers in N-Butyl-N-(4-Hydroxybutyl)Nitrosamine-Induced Bladder Carcinogenesis in Rats.

We investigated γ-H2AX formation, a biomarker of DNA damage, and expression of stem cell markers (SCMs), including cytokeratin 14, aldehyde dehydrogenase 1A1 (ALDH1A1), and CD44, in the development of rat bladder tumors induced by short-term administration of N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN). Histopathological examination showed that diffuse simple hyperplasia of the bladder urothelium induced by BBN recovered to the normal-appearing urothelium after withdrawal, whereas focal proliferative lesions were newly developed and subsequently progressed to benign papilloma and carcinoma. Immunohistochemical analysis revealed that BBN-induced γ-H2AX formation and ALDH1A1 and CD44 expression persisted at higher levels in the normal-appearing urothelium than those in the control group for long periods after withdrawal. Since persistent chronic inflammation was observed even after withdrawal, targeted gene expression analysis of inflammation-related factors revealed 101 genes, including Stat3 and Myc, that showed persistent high expression. Pathway analysis suggested that Stat3 and/or Myc activation may be associated with SCM expression. We focused on hepatocyte growth factor (Hgf), one of the genes predicted in relation to Stat3/Myc, and confirmed that HGF-positive cells increased by BBN persisted in the normal-appearing urothelium after withdrawal and colocalized with γ-H2AX and SCMs. These results suggested that the long-term persistence of γ-H2AX formation and SCM expression, which occurred during the early stages of bladder tumorigenesis, is not a transient response to exposure and might contribute to bladder tumorigenesis. Although further studies are needed, BBN-induced rat bladder tumors may originate from focal hyperplasia arising from SCM-positive cells via activation of the STAT3/MYC pathway after DNA damage involving γ-H2AX formation.

Risk of Pulmonary-Reproductive Dysfunctions, Inflammation and Oxidative DNA Damage in Exposure to Polycyclic Aromatic Hydrocarbon in Cigarette Smokers.

Background: Exposure to cigarette smoke has been associated with pulmonary and reproductive dysfunctions; inflammatory response, oxidative stress and oxidative DNA damage induced by polycyclic aromatic hydrocarbons (PAHs) present in cigarette smoke have been implicated in the pathogenesis of these disorders. The peak expiratory flow rate (PEFR), a biomarker of inflammation and oxidative DNA damage (8-hydroxy-2-deoxyguanosine (8-OHdG), tumor necrosis factor alpha (TNF-α)), reproductive hormones (testosterone (TST), luteinizing hormone (LH), follicle stimulating hormone (FSH)) cotinine and urinary PAH metabolite (1-hydroxypyrene (1-HOP)) were estimated in male active smokers. Methods: One hundred men aged 20-47 years, comprising 50 active male smokers and 50 non-smokers, were randomly recruited into this comparative cross-sectional study. The PEFR was measured using a peak flow meter, serum levels of cotinine, FSH, LH, TST, TNF-α, and urine 8-OHdG by enzyme-linked immunosorbent assay and 1-HOP by high-performance liquid chromatography. Data analysis was done using a t-test and correlation analysis at p≤0.05. Results: Smokers had significantly higher cotinine (49.73±31.76 versus 0.51±0.69 ng/ml, p≤0.001), 8-OHdG (16.34±12.10 versus 5.79±2.14 ng/ml, p≤0.001) and lower PEFR (309.20±56.05 versus 452.80±45.76 L/min, p≤0.001) and LH (5.75±2.06 versus 6.97±2.79 mIU/ml, p=0.015) compared to non-smokers. Duration of exposure to cigarette smoke correlated positively with cotinine (r=0.937, p≤0.001) and 1-HOP (r=0.813, p≤0.001) while cotinine correlated positively with 1-HOP (r=0.863, p≤0.001) only in smokers. Conclusion: Reduced lung function and luteinizing hormone and concurrent increase in oxidative DNA damage associated with exposure to cigarette smoke may suggest the involvement of PAH-induced DNA damage in the development of pulmonary and reproductive impairment in smokers.

Associations of polychlorinated biphenyls exposure with plasma glucose and diabetes in general Chinese population: The mediating effect of lipid peroxidation

Polychlorinated biphenyls (PCBs) exposure has been related to the abnormal glucose metabolism and the risk of diabetes. However, the joint effects of various PCBs are uncertain and the potential mechanisms remain unclear. Our objectives were to evaluate the associations of serum PCBs with fasting plasma glucose (FPG) and the risk of diabetes among a general Chinese population, and to estimate the mediating effects of oxidative stress in the above associations. Serum levels of seven indicator-PCBs (PCB-28, 52, 101, 118, 138, 153, and 180) and FPG values were determined among 4498 subjects from the Wuhan-Zhuhai cohort. Oxidative DNA damage biomarker (urinary 8-hydroxy-2′-deoxyguanosine, 8-OHdG) and lipid peroxidation biomarker (urinary 8-isoprostane, 8-iso-PGF2α) were also measured. Positive relationships of serum PCBs with FPG values as well as the risk of diabetes were observed. With each 1% increment in the natural log-transformed values of wet weight serum PCBs, FPG levels increased a 0.125% for PCB-52, 0.168% for PCB-118, 0.221% for PCB-138, 0.273% for PCB-153, and 0.379% for ΣPCB (the sum of seven PCBs). The adjusted odds ratios of diabetes associated with wet weight PCBs were 1.186 for PCB-52, 1.373 for PCB-118, 1.635 for PCB-153, and 1.456 for ΣPCB. The seven serum PCBs showed positive overall effect on the risk of diabetes. Elevated PCB-28, PCB-52, PCB-118, PCB-138, PCB-153, and ΣPCB were associated with the increased urinary 8-iso-PGF2α, which was positively related with FPG values. Furthermore, urinary 8-iso-PGF2α partially mediated the positive associations between PCBs and FPG values, with the mediated proportions ranged from 3.20 to 12.93%. In conclusion, our results suggested that serum PCBs were positively related with increased oxidative stress, FPG values, and the risk of diabetes among a general Chinese population. Serum PCBs mixture had positive overall effect on the risk of diabetes. Lipid peroxidation partly mediated the FPG elevation induced by PCB exposure.

Combined therapy with dapagliflozin and entresto offers an additional benefit on improving the heart function in rat after ischemia-reperfusion injury

BackgroundThis study tested whether combined dapagliflozin and entresto treatment would be superior to either one alone for preserving the left-ventricular ejection-fraction (LVEF) in rat after ischemia-reperfusion (IR) injury. MethodsCell culture using H9C2 cells and IR injury in rat with dapagliflozin-entresto treatment were conducted in the present study. ResultsIn vitro flow-cytometric result showed that the intracellular and mitochondrial reactive oxygen species and mitochondrial permeability transition pore, and protein levels of oxidative-stress/DNA-damaged markers [NADPH-oxidase-1 (NOX-1)/NOX-2/oxidized-protein/γ-H2A-histone-family member X (γ-H2AX)] were significantly higher in hydrogen peroxide (H2O2) (300μM)-treated H9C2 cells as compared with the controls that were significantly reversed in sacubitril/valsartan and dapagliflozin therapy in the same H2O2-treated condition, whereas the protein expressions of antioxidants [Sirtuin-1 (SIRT1)/SIRT3/superoxide dismutase/catalase/glutathione peroxidase) exhibited an opposite pattern among the groups (all p<0.001). Adult-male-Sprague-Dawley rat (n=40) were equally categorized into group 1 (sham-operated control), group 2 (IR), group 3 (IR+dapagliflozin/20mg/kg/orally at 3h and post-days 1/2/3 after IR), group 4 (IR+entresto/100mg/kg/orally at 3h and post-days 1/2/3 after IR) and group 5 (IR+dapagliflozin+entresto) and the hearts were harvested by day 3 after IR. The 3rd day’s LVEF was highest in group 1, lowest in group 2 and significantly higher in group 5 than in groups 3/4, but it was similar between the latter two groups (p<0.001). The protein expressions of oxidative-stress (NOX-1/NOX-2/oxidized protein), fibrotic (transforming-growth factor-ß/phosphorylated-Smad3), apoptotic [mitochondrial-Bax/cleaved-caspase-3/cleaved-poly (ADP-ribose) polymerase], mitochondria/DNA damaged (cytosolic-cytochrome-c/γ-H2AX), pressure-overload/heart-failure [brain natriuretic peptide (BNP)/ß-myosin heavy chain] and autophagic (ratio of meiotic cyclins CLB3-II/CLB3-I) biomarkers, and the upstream (high-mobility group box 1/Toll-like receptor-4/MyD88/phosphorylated-nuclear factor-κB and downstream [interleukin (IL)-1ß/IL-6/tumor necrosis factor-α] inflammatory signalings revealed an antithetical features of LVEF among the groups (all p<0.0001). The cellular levels of inflammatory (myeloperoxidase+/CD68+), pressure-overload/heart-failure (BNP+) and DNA-damage (γ-H2AX+) biomarkers as well as infarct area demonstrated an opposite pattern of LVEF among the groups (all p<0.0001). ConclusionIncorporated entresto-dapagliflozin treatment was superior to either one alone on protecting the heart against IR injury.

Abstract LB520: A pharmacodynamic platform using liquid biopsy to support dose selection for the ATR inhibitor ART0380 (IACS-030380)

Abstract Inhibition of ataxia telangiectasia and Rad-3 related (ATR) kinase offers therapeutic promise for DNA damage response deficient tumors. In addition, ATR inhibitors may offer even broader clinical utility when combined with PARPi’s, chemo, immune or radiation therapy. Flat-fixed dosing of ATR inhibitors alone or in combination has provided clinical benefit but is associated with on target, dose limiting haematological toxicity. Strategies to refine dose selection of this class of medicine may further optimize clinical benefit. The aim of our ongoing investigation is to determine if the dose selection for clinical development of the novel ATR inhibitor ART0380 (IACS-030380) may be optimized based on the degree of PD engagement in both tumor and normal tissue from patients. To do this, we have utilized in vitro and in vivo cancer models to help us understand the dynamic and temporal response to several biomarkers of ATR inhibition and DNA damage. Once established in vitro, we selected key markers, such as γH2AX and pKAP1, to explore in vivo using doses predicted to be biologically effective in man and have shown that these are modulated following exposure to ART0380. To enable the serial assessment of PD engagement in both tumor and normal tissue, we have developed an assay in the phase 1 study of ART0380 (NCT04657068) to measure γH2AX levels in circulating tumor cells (CTC’s) and normal cells (PBMC’s). A significant advantage of this approach is that samples are taken from the same blood draw and at several timepoints following exposure to ART0380. So far, our studies have shown that in patients, who have experienced drug exposures predicted to be biologically effective, γH2AX levels in CTC’s increase by up to 20% respectively from baseline while γH2AX in PBMC’s remains unaffected. This observation may highlight that target engagement has taken place for ART0380 in the tumor without an effect in normal tissue, a phenomena perhaps explained by the pharmacokinetic profile of ART0380. The clinical study is ongoing and we continue to monitor individual patient responses, toxicity, and correlate with PD engagement in tumor and normal tissue circulating biopsies. In addition, we are now expanding our analysis into a multiplexed assay where we will measure pKAP1 as well as γH2AX to build a more detailed assessment of PD activity in patients. Updated data will be presented. Citation Format: Manish Patel, Kathleen N. Moore, Desiree Piscitello, Jayesh Majithiya, Marina Roy Luzarraga, Helen Millward, Sarah V. Holt, Melissa Johnson. A pharmacodynamic platform using liquid biopsy to support dose selection for the ATR inhibitor ART0380 (IACS-030380) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB520.

Abstract 5485: Discovery and preclinical evaluation of a novel highly selective and potent CDK12 inhibitor

Abstract Recent research highlights that RNA processing is systematically altered in cancer, demonstrating the pivotal influence of RNA deregulation on tumorigenesis, growth and progression. Based on our expanding knowledge of RNA biology, RNA deregulation has drawn much attention from the perspective of cancer therapy. Indeed, small molecules that attack the RNA maturation processes and produce aberrant RNA are currently under development. The first step in gene expression is transcription, which involves copying a DNA sequence to make an RNA. Transcription is performed by enzymes called RNA polymerase (Pol II) that links nucleotides to form RNA strand. The C-terminal domain (CTD) of Pol II comprises heptapeptide Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7 repeats and is dynamically post-translationally phosphorylated to regulate the distinct stages of transcription initiation, elongation and termination steps. Particularly, Ser2 and Ser5 phosphorylation have the closest association with the regulation of transcription. Therefore, we focus on the kinases that carry out this modification. Cyclin-dependent kinase 12 (CDK12) belongs to the cyclin-dependent kinase (CDK) family of serine/threonine protein kinases. CDK12 regulates the elongation step of RNA transcription by phosphorylation of Ser2 on the CTD. CDK12 complexes with cyclin K to promote the elongation of transcripts, such as BRCA1 and BRCA2, involved in DNA damage responses. It is expected that the inhibition of CDK12 have a synergistic effect with PARP inhibitors and chemotherapeutic reagents. Here we present data on CRD-1835439, orally available, selective, and first in class CDK12 inhibitor with optimized drug-properties. Biochemically, CRD-1835439 is more than 300-fold selective over other CDK isoforms such as CDK7 and CDK9. Importantly, cell based assays showed CRD-1835439 has selective inhibitory activity for phosphorylation of Ser2 on the CTD but not for other Ser5 and Ser7 phosphorylation. Comprehensive analysis by PolyA-seq, Chip-seq and RNA-seq revealed that CRD-1835439 inhibits transcriptional elongation on DNA damage response genes including BRCA1 and BRCA2. The effects on DNA damage and repair were assessed by immunofluorescence staining for γH2AX and RAD51 proteins. In vivo, oral treatment with CRD-1835439 in cell line derived xenograft models, resulted in increase of DNA damage biomarkers, induction of apoptosis and tumor regressions in a dose-dependent fashion. Besides the efficacy as a single reagent, the efficacy was augmented when CRD-1835439 was combined with PARP inhibitors in in vitro and in vivo. In summary, the novel small-molecule CDK12 inhibitor CRD-1835439 demonstrated preclinical efficacy along with target engagement. Our results underscore the preclinical therapeutic potential of CRD-1835439 as a single-agent or in combination with PARP inhibitors for the treatment of intractable cancers. Citation Format: Hiroko Yamakawa, Akio Mizutani, Yasuyoshi Arikawa, Shunsuke Ebara, Yoshihiko Satoh, Daisuke Morishita. Discovery and preclinical evaluation of a novel highly selective and potent CDK12 inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5485.

Four-year population exposure study: Implications for the effectiveness of e-waste control and biomarkers of e-waste pollution

E-waste pollution has emerged as a significant environmental concern. To assess the impact of e-waste control on human pollutant exposure risk and identify appropriate biomarkers to classify e-waste pollution levels, we performed longitudinal population exposure monitoring research in an e-waste recycling area in China after e-waste control. The urinary levels of oxidative stress markers and typical pollutants emitted during e-waste recycling, including heavy metals, polycyclic aromatic hydrocarbons (PAHs), and volatile organic compounds (VOCs), were continuously monitored in the surrounding population (including 275 children and 485 adults) from 2016 to 2019 using high-performance liquid chromatography-tandem mass spectrometry and inductively coupled plasma–mass spectrometry. The results showed that exposure to PAHs, VOCs and heavy metals was significantly associated with oxidative stress levels in urine. After e-waste control, the exposure levels of most PAHs and VOCs and a few heavy metals in the population significantly decreased. Interestingly, the level of 8-hydroxy-2′-deoxyguanosine (a biomarker of oxidative DNA damage) in children significantly decreased by 17.6 %, from 9.45 μg/g CRE in 2017 to 7.79 μg/g CRE in 2019 (p < 0.01). Thus, implementing e-waste control measures effectively reduced the human exposure risk to e-waste pollutants. Urinary tin (Sn), s-phenylmercapturic acid (PMA), 2-&3-hydroxyfluorene (2-&3-OHF), 3-hydroxyphenanthrene (3-OHPhe), and 1-hydroxypyrene (1-OHP) levels decreased significantly and monotonically over time (p < 0.01). The levels of urinary Sn and PMA in combination with 1-OHP, 2-&3-OHF, or 3-OHPhe as biomarkers demonstrated an excellent ability to classify e-waste pollution. These biomarkers will facilitate evaluations of the effectiveness of the governmental pollution regulations and policy measures. Additionally, children were generally exposed to higher levels of heavy metals and VOCs and suffered higher levels of oxidative stress damage than adults, suggesting that children are more vulnerable to e-waste pollution. This work will provide a reference for e-waste management and control.

0025 Circadian Dysregulation of Human DNA Repair Genes and Elevated DNA Damage in Simulated Night Shift Schedule

Abstract Introduction Circadian misalignment from night shift (NS) work is associated with increased risk of cancer. In a simulated NS study, we sought to investigate the potential role of circadian disruption of cancer hallmark pathway genes. Methods N=14 healthy adults (aged 22-34) participated in a laboratory study. Seven were assigned to a simulated day shift (DS) schedule involving 3 days of daytime wakefulness (06:00-22:00); the other seven were assigned to a simulated NS schedule involving 3 days of nighttime wakefulness (18:00-10:00). Subjects then underwent a 24-hour constant routine protocol, during which blood was collected at 3-hour intervals. Leukocytes extracted from blood were subjected to transcriptomics using the NanoString nCounter PanCancer Pathways panel augmented with canonical clock genes. Statistical analysis involved mixed-effects cosinor analysis followed by functional enrichment analysis of rhythmic genes. Leukocytes were also subjected to endogenous DNA damage assessment through alkaline comet and immunofluorescence assays. Furthermore, exogenous DNA damage from exposure to ionizing radiation was investigated for blood collected at opposite times of day (07:30 and 19:30) based on DNA damage biomarkers assessed with immunofluorescence and immunoblot assays. Results Transcriptomics data showed that the simulated NS schedule, as compared to the simulated DS schedule, significantly altered the endogenous circadian rhythmicity of genes involved in cancer hallmark pathways, as measured under constant routine. A DNA repair pathway showed enrichment of rhythmic genes following the DS schedule (P&amp;lt;0.05), but not following the NS schedule. Functional assessments revealed that the NS schedule was associated with increased endogenous DNA damage, as evidenced by alkaline comet assay (P&amp;lt;0.001) and increased BRCA1 foci (P&amp;lt;0.01) and γH2AX foci by immunofluorescence assay (P&amp;lt;0.001). After exposure to ionizing radiation, there were increased BRCA1 foci (P&amp;lt;0.01) and γH2AX foci by immunofluorescence assay (P&amp;lt;0.005) and elevated DNA damage response signaling biomarkers by immunoblot assay, especially in the samples collected at 19:30. Conclusion These results suggest that a NS schedule causes circadian dysregulation of DNA repair genes and increases DNA damage – a primary hallmark of carcinogenesis – which may underlie the elevated cancer risk in NS workers. Support (If Any) WSU, CHHE P30ES025128, USAMRDC W81XWH-18-1-0100, NIH R01ES030113 and R21CA227381, CDMRP CA171123, DOE BRAVE DE-AC05-76RL01830.

Red orange and lemon extract preserve from oxidative stress, DNA damage and inflammatory status in lambs

Oxidative stress causes several pathological conditions in farm animals by inducing a reduction in animal welfare and production with major economic losses for livestock. The standardised phytoextract obtained by red orange and lemon processing has antioxidant and anti-inflammatory activities. In this study we have investigated whether treating lambs for 40 days with red orange and lemon extract (RLE) was able to prevent the antioxidant and anti-inflammatory mechanisms, typically in newborn period. For this purpose, at the end of treatment, redox status was assessed in plasma using oxidative stress markers: malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) activities. Moreover, 8-hydroxy-2’-deoxyguanosine (8-OHdG) in urine was measured as a biomarker of DNA damage and finally, the markers of inflammatory status, interleukin (IL) 1β and 6, were measured in plasma by using an enzyme-linked immunosorbent assay (ELISA). Results showed that RLE-treated lambs improved antioxidant mechanisms as demonstrated by the increase in SOD, CAT and GPx activities and, furthermore, a significant reduction in oxidative stress-induced damage was demonstrated through MDA and 8-OHdG measurements. Moreover, RLE was also able to prevent the increase of pro-inflammatory cytokines concentration, such as IL- 1 β and IL 6. Results showed in the present paper demonstrate the potential beneficial effects of the RLE in lambs. HIGHLIGHTS Oxidative stress causes economic loss and welfare impairment in livestock. Several oxidative markers can be used to assess the redox status in plasma. The activity of some antioxidant enzymes increased in RLE treated lambs. A reduction of pro-inflammatory cytokines was recorded in RLE treated lambs.

Urinary concentrations of amphenicol antibiotics in relation to biomarkers of oxidative DNA and RNA damage in school children

Previous studies implied that elevated exposure to amphenicol antibiotics may induce increased oxidative stress. However, the effects of amphenicol antibiotics exposure on oxidative stress damage in human have not been well studied. This study examined the associations between amphenicol antibiotics exposure and oxidative damage biomarkers in school children. Three major amphenicols including chloramphenicol (CAP), thiamphenicol (TAP), florfenicol (FF) and two biomarkers of 8-hydroxydeoxyguanosine (8-OHdG) for oxidative DNA damage and 8-oxo-7,8- dihydroguanosine (8-OHG) for oxidative RNA damage were measured in 414 morning urine samples collected from 70 school children in Shanghai, China. School children were exposed to CAP, TAP, and FF with median concentrations of 1.37, 0.36, and 0.06 μg/g Cre, respectively. Linear mixed models revealed that an interquartile range (IQR) increase of urinary TAP was positively associated with 7.75%(95% CI: 4.40%, 11.1%) increase of 8-OHdG and 7.48%(95% CI: 2.49%, 15.6%) increase of 8-OHG, respectively; in addition, CAP was associated with elevated 8-OHdG. Although FF was not found to be significantly associated with either 8-OHdG or 8-OHG, it is warranted to further investigate FF and its metabolites levels in relation to oxidative stress in future study. Our findings provide new evidence for the effects of exposure to TAP and CAP on nucleic acid oxidative damage in Children.

Wasp Venom Relieves Alzheimer's Phenotypes in 5xFAD Transgenic Mice through Inhibition of Aβ Aggregation

Alzheimer’s disease (AD), a neurodegenerative disorder, has been known to be mostly commonly diagnosed in people over the age of 65. However, there is no drug that can cure AD. This study aimed to investigate if wasp venom (WV) can mitigate phenotypes of AD using a 5xFAD transgenic mouse model. The mice were administered intraperitoneally with WV obtained from Vespa velutina at a concentration of 250 or 400 μg/kg body weight (BW) once a week for a total of 14 weeks. WV treatment was shown to alleviate memory impairments in 5xFAD mice in behavioral tasks, including passive avoidance, Y‐maze and Morris water maze tests. In addition, we found that WV treatment decreased the level of 8‐hydroxy‐2′‐deoxyguanosine, a biomarker of oxidative DNA damage, in mouse plasma and the level of malondialdehyde, an indicative of lipid peroxidation, in liver and cerebral cortex, indicating that WV prevents oxidative damage. In particular, WV treatment increased expression of antioxidant‐associated proteins, a nuclear factor erythroid‐derived 2‐related factor 2 (Nrf2) and heme oxygenase‐1 (HO‐1), in the cerebral cortex and decreased inflammation‐associated protein, cyclooxygenase‐2 (COX‐2), amyloid beta (Aβ) plaque‐associated proteins, C‐terminal fragment (C99), and beta‐site amyloid precursor protein cleaving enzyme 1 (BACE1, β‐secretase) in the hippocampal tissue homogenates. Furthermore, we confirmed that WV treatment reduced the accumulation of Aβ plaque in the hippocampal area via thioflavin S staining. Taken together, these findings suggest that WV could ameliorate AD symptoms and delay AD onset and progression.

Effects of Concurrent Exposure to Chronic Restraint-Induced Stress and Total-Body Iron Ion Radiation on Induction of Kidney Injury in Mice.

Concurrent exposure to ionizing radiation (IR) and psychological stress (PS) may affect the development of adverse health consequences in scenarios such as space missions, radiotherapy and nuclear accidents. IR can induce DNA damage and cell apoptosis in the kidneys, thus potentially leading to renal fibrosis, which is the ultimate outcome of various chronic progressive nephropathies and the morphological manifestation of a continuous coordinated response after renal injury. However, little is known regarding the effects of concurrent IR exposure and PS on renal damage, particularly renal fibrosis. In this study, using a chronic restraint-induced PS (CRIPS) model, we exposed Trp53-heterozygous mice to total body irradiation with 0.1 or 2 Gy 56Fe ions on the eighth day of 28 consecutive days of a restraint regimen. At the end of the restraint period, the kidneys were collected. The histopathological changes and the degree of kidney fibrosis were assessed with H&E and Masson staining, respectively. Fibronectin (FN) and alpha smooth muscle actin (α-SMA), biomarkers of fibrosis, were detected by immunohistochemistry. Analysis of 8-hydroxy-2 deoxyguanosine (8-OHdG), a biomarker of oxidative DNA damage, was performed with immunofluorescence, and terminal deoxynucleotidyl transferase-mediated nick end labeling assays were used to detect apoptotic cells. Histopathological observations did not indicate significant structural damage induced by IR or CRIPS + IR. Western blotting revealed that the expression of α-SMA was much higher in the CRIPS + IR groups than the CRIPS groups. However, no differences in the average optical density per area were observed for FN, α-SMA and 8-OHdG between the IR and CRIPS + IR groups. No difference in the induction of apoptosis was observed between the IR and CRIPS + IR groups. These results suggested that exposure to IR (0.1 and 2 Gy 56Fe ions), 28 consecutive days of CRIPS or both did not cause renal fibrosis. Thus, CRIPS did not alter the IR-induced effects on renal damage in Trp53-heterozygous mice in our experimental setup.

Evaluation of heavy metals and biomarkers of deoxyribonucleic acid damage in state employment and expenditure for result contract workers in Yenagoa

&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;Youth unemployment and poverty in Southern Nigeria is high, thus many youths are easily recruited as dock workers and casual labourers without considering the occupational hazards associated with such jobs. This study evaluated some heavy metals and DNA damage biomarkers in state employment and expenditure for result (SEEFOR) contract workers, in Yenagoa.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Method: &lt;/strong&gt;One hundred subjects between the age range of 20 to 55 years, comprising fifty of SEEFOR contract workers and fifty unexposed individuals as control in the study. Blood samples were collected, separated and sera used for the analyses of heavy metals and DNA damaged biomarkers using enzyme linked immunosorbent assay and atomic absorption spectrophotometry.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;The result showed statistically non-significant difference (p&amp;gt;0.05) values of cadmium, chromium, vanadium, nickel, arsenic and DNA damage biomarkers at the baseline compared with the control group. Cadmium, vanadium and 8-NO&lt;sub&gt;2&lt;/sub&gt;-Gua at the 6&lt;sup&gt;th&lt;/sup&gt; month showed statistically significant difference (p&amp;lt;0.05). Statistically significant (p&amp;lt;0.05) increase at 12&lt;sup&gt;th&lt;/sup&gt; month were equally observed in cadmium, vanadium, nickel, arsenic, and 8-NO&lt;sub&gt;2&lt;/sub&gt;-Gua compared with the control. Heavy metals cadmium, chromium, Vanadium values showed statistically significant (p&amp;lt;0.005) increase in both the 18&lt;sup&gt;th&lt;/sup&gt; and 24&lt;sup&gt;th&lt;/sup&gt; month. DNA damage biomarkers 8-NO&lt;sub&gt;2&lt;/sub&gt;-Gua, 4HNE, and BPDE levels also showed a significant (p&amp;lt;0.005) increase at the 18&lt;sup&gt;th&lt;/sup&gt; and 24&lt;sup&gt;th&lt;/sup&gt; month when compared with the control group.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;The study suggest that the probability of occurrence of diseases related to heavy metal bioaccumulation and DNA damage originating from oxidative stress, might be higher among SEEFOR road construction workers with time.&lt;/p&gt;

Effects of sub-chronic exposure of male albino rats to some insecticides on mitochondrial dysfunction and oxidative stress in the kidney with molecular docking

The present study evaluated the adverse effects of three widely used insecticides in the Egyptian environment on mitochondrial bioenergetic and oxidative stress biomarkers in the rat kidney. Chlorpyrifos, cypermethrin, and imidacloprid were orally administrated to male albino rats at 1/50 of the LD50 for 28 days by 5 doses /week. The insecticides caused a significant in vivo decrease in the activities of mitochondrial bioenergetic biomarkers; NADH dehydrogenase, adenosine triphosphatase (ATPase) and mitochondrial oxidative stress biomarkers; superoxide dismutase (SOD), and glutathione S- transferase (GST) while the malondialdehyde (MDA) and protein carbonyl contents (PCC) were significantly increased. Further, chromatography analysis demonstrated that 8-hydroxy-2'-deoxyguanosine (8-OH-2DG) increased considerably in rat urine as a DNA damage biomarker. The kidney deficiency was confirmed by histological examination and in silico simulation analysis (Molecular docking and absorption, distribution, metabolism, excretion, and toxicity (ADMET)). The alterations in the tested parameters were confirmed by the symptoms of histological deformation in kidney tissues, demonstrating the hazardous effects. The laboratory results showed the impact of the tested insecticides in conformity with the in silico simulation analysis (molecular docking and ADMET).

Oxidative stress of glyphosate, AMPA and metabolites of pyrethroids and chlorpyrifos pesticides among primary school children in Cyprus

BackgroundExposure to various pesticides, such as pyrethroids and chlorpyrifos, has been previously associated with adverse effects on children's health. Scientific evidence on the human toxicity of glyphosate (GLY) and its primary metabolite, aminomethylphosphonic acid (AMPA) is limited, particularly for children. This study aimed to i) assess the exposure determinants of the studied pesticides measured in children in Cyprus, and ii) determine the association between the urinary pesticides and the biomarkers of DNA and lipid oxidative damage. MethodsA children's health study was set up in Cyprus (ORGANIKO study) by aligning it with the methodology and tools used in the European Human Biomonitoring Initiative (HBM4EU). Urinary GLY and AMPA, pyrethroid metabolites and the chlorpyrifos metabolite TCPy were measured in 177 children aged 10–11 years old, using mass spectrometry. Oxidative stress was assessed with 8-iso-prostaglandin F2a (8-iso-PGF2α) as a marker of lipid damage and 8-hydroxy-2′-deoxyguanosine (8-OHdG) as a DNA oxidative damage marker, both measured with immunoassays. Questionnaires about demographic characteristics, pesticide usage, and dietary habits were filled out by the parents. Μultivariable regression models examined associations between pesticides and biomarkers of effect using two creatinine adjustments (cr1: adding it as covariate and cr2: biomarkers of exposure and effect were creatinine-adjusted). ResultsParental educational level was a significant predictor of urinary pyrethroids but not for GLY/AMPA. Median [interquartile range, IQR] values for GLY and AMPA were <LOQ [<LOQ, 0.19] μg/L and 0.18 [0.10, 0.29] μg/L, respectively, while a moderate correlation was shown between GLY and AMPA (r = 0.45). 8-OHdG was positively associated with AMPA (beta = 0.17; 95% CI: 0.02, 0.31, p = 0.03 cr2, and beta = 0.12; 95% CI: 0.0,0.24, p = 0.06, cr1), albeit not with GLY (p > 0.05). Similar significant associations with 8-OHdG were shown for a pyrethroid metabolite (3-PBA) and the chlorpyrifos metabolite (TCPy). No associations were observed between the aforementioned pesticides and 8-iso-PGF2α (p > 0.05). ConclusionsThis is the first children's health dataset demonstrating the association between AMPA and DNA oxidative damage, globally. More data is needed to replicate the observed trends in other children's populations around the globe.

Melatonin Attenuates Inflammation, Oxidative Stress, and DNA Damage in Mice with Nonalcoholic Steatohepatitis Induced by a Methionine- and Choline-Deficient Diet.

Nonalcoholic steatohepatitis (NASH) is a disease with a high incidence worldwide, but its diagnosis and treatment are poorly managed. In this study, NASH pathophysiology and DNA damage biomarkers were investigated in mice with NASH treated and untreated with melatonin (MLT). C57BL/6 mice were fed a methionine- and choline-deficient (MCD) diet for 4weeks to develop NASH. Melatonin was administered at 20mg/kg during the last 2weeks. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were measured, and hepatic tissue was dissected for histological analysis, evaluation of lipoperoxidation, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), as well as nuclear factor-erythroid 2 (Nrf2), tumor necrosis factor alpha (TNF-α), inducible nitric oxide synthase (iNOS), and transforming growth factor beta (TGF-β) expression by immunohistochemistry. DNA damage was evaluated using Comet assay, while a micronucleus test in bone marrow was performed to assess the genomic instability associated with the disease. Melatonin decreased AST and ALT, liver inflammatory processes, balloonization, and fibrosis in mice with NASH, decreasing TNF-α, iNOS, and TGF-β, as well as oxidative stress, shown by reducing lipoperoxidation and intensifying Nrf2 expression. The SOD and GPx activities were increased, while CAT was decreased by treatment with MLT. Although the micronucleus frequency was not increased in mice with NASH, a protective effect on DNA was observed with MLT treatment in blood and liver tissues using Comet assay. As conclusions, MLT slows down the progression of NASH, reducing hepatic oxidative stress and inflammatory processes, inhibiting DNA damage via anti-inflammatory and antioxidant actions.

Salinity gradients exacerbate the genotoxicity and bioaccumulation of silver nanoparticles in fingerling Persian sturgeon (Acipenser persicus)

As nanoparticles are extensively applied in a vast range of products and so are released into marine environments, their effects and the involved mechanisms on such ecosystems need to be further investigated. Therefore, the present study examined the effects of salinity on the toxicity of silver nanoparticles (AgNPs) using DNA damage biomarker and bioaccumulation process in fingerling Persian sturgeon (Acipenser persicus). A total of 360 fingerling fish with an average weight of 2.95 ± 0.25, 3.49 ± 0.35 and 4.04 ± 0.35 were used for the salinity gradients of 0.4, 6 and 12 g L−1 (ppt), respectively. Fish acclimated to freshwater (0.4 ppt) for 14 d were exposed to 0, 0.07, 0.1, and 0.2 mg L−1 AgNPs, while those kept in brackish water (6 and 12 ppt) were exposed to 0, 0.2, 0.3, and 0.6 mg L−1 AgNPs through a sub-chronic exposure test. Fish sampling was conducted on the day 0 and 14 and bioaccumulation and DNA damage tests were implemented using liver, gills and intestine organs. Results showed that AgNPs exposure could induce concentration-dependent DNA damage in the liver single cells, while elevating salinity significantly increased tail moment index in the fish. Ag bioaccumulation in the investigated tissues was greatest in liver, followed by gill, then intestine. Furthermore, elevated salinity significantly increased the bioaccumulation of Ag in the liver. Behavioral analysis showed the marked emergence of abnormal manners with the increase of salinity and AgNPs concentrations. Together, salinity changes, as one of the most important environmental stressors, can significantly affect the toxicity of emerging pollutants such as AgNPs in the marine biota, and ecologically- and commercially-important fish species like Persian sturgeon are in a cautious status in the Caspian Sea.

Antioxidant Potential, DNA Damage, Inflammation, Glycemic Control and Lipid Metabolism Alteration: A Mediation Analysis of Islamic Sunnah Intermittent Fasting on Cognitive Function among Older Adults with Mild Cognitive Impairment.

This study aimed to determine the relationship between oxidative stress, DNA damage, inflammation, and metabolic biomarkers as the mediating factor between Islamic Sunnah intermittent fasting (IF) practice and cognitive function among older adults with mild cognitive impairment (MCI). This study was a 36 months prospective cohort study. Community-dwelling older participants recruited through a stratified random sampling method from four states representing Malaysia's central, north-west, northeast and southern regions. Ninety-nine Malay Muslim older adults (n= 99) aged 60 and above with MCI and no known critical illnesses were included in the current analysis. The participants were divided into regularly practicing IF (r-IF), irregularly practicing IF (i-IF) and not practicing IF (n-IF) groups. Fasting venous blood was collected and used to determine the levels of oxidative stress, DNA damage, inflammatory and metabolic biomarkers. Mini-Mental State Examination, Montreal Cognitive Assessment, Rey Auditory Verbal Learning Test, Digit Span and Digit symbol were used to evaluate the cognitive function. Then, the mediation analysis was conducted using a multistep regression model to determine the mediating role of various biomarkers between IF practice and cognitive function. When comparing the r-IF and n-IF groups, higher SOD activity, lower DNA damage (percentage of DNA in tail), lower CRP levels and higher HDL-cholesterol levels established partial mediation while lower insulin levels established complete mediation between IF practice and better cognitive function. Meanwhile, when comparing the r-IF and i-IF groups, higher SOD activity and lower CRP levels completely mediated the effects of IF practice on better cognitive function. It can be concluded that changes in antioxidant function, DNA damage, inflammation and a limited set of metabolic biomarkers (insulin and HDL cholesterol) may mediate improvements in cognitive function among older participants with MCI who practice Islamic Sunnah IF.