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The Journal of Organic Chemistry Jul 20202'-Deoxyguanosin-1-yl radical (dG(-H)) is the thermodynamically favored one-electron oxidation product of 2'-deoxyguanosine (dG), the most readily oxidized native...
2'-Deoxyguanosin-1-yl radical (dG(-H)) is the thermodynamically favored one-electron oxidation product of 2'-deoxyguanosine (dG), the most readily oxidized native nucleoside. dG(-H) is produced by the formal dehydration of a hydroxyl radical adduct of dG as well as by deprotonation of the corresponding radical cation. dG(-H) were formed as a result of the indirect and direct effects of ionizing radiation, among other DNA damaging agents. dG(-H) was generated photochemically (λ = 350 nm) from an -aryloxy-naphthalimide precursor (). The quantum yield for photochemical conversion of is ∼0.03 and decreases significantly in the presence O, suggesting that bond scission occurs from a triplet excited state. dG is formed quantitatively in the presence of excess β-mercaptoethanol. In the absence of a reducing agent, dG(-H) oxidizes , decreasing the dG yield to ∼50%. Addition of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) as a sacrificial reductant results in a quantitative yield of dG and two-electron oxidation products of 8-oxodGuo. -Aryloxy-naphthalimide is an efficient and high-yielding photochemical precursor of dG(-H) that will facilitate mechanistic studies on the reactivity of this important reactive intermediate involved in DNA damage.
Topics: 8-Hydroxy-2'-Deoxyguanosine; DNA Damage; Deoxyguanosine; Hydroxyl Radical; Oxidation-Reduction
PubMed: 32525316
DOI: 10.1021/acs.joc.0c01095 -
Annals of Neurology Aug 2019Thymidine kinase 2, encoded by the nuclear gene TK2, is required for mitochondrial DNA maintenance. Autosomal recessive TK2 mutations cause depletion and multiple...
OBJECTIVE
Thymidine kinase 2, encoded by the nuclear gene TK2, is required for mitochondrial DNA maintenance. Autosomal recessive TK2 mutations cause depletion and multiple deletions of mtDNA that manifest predominantly as a myopathy usually beginning in childhood and progressing relentlessly. We investigated the safety and efficacy of deoxynucleoside monophosphate and deoxynucleoside therapies.
METHODS
We administered deoxynucleoside monophosphates and deoxynucleoside to 16 TK2-deficient patients under a compassionate use program.
RESULTS
In 5 patients with early onset and severe disease, survival and motor functions were better than historically untreated patients. In 11 childhood and adult onset patients, clinical measures stabilized or improved. Three of 8 patients who were nonambulatory at baseline gained the ability to walk on therapy; 4 of 5 patients who required enteric nutrition were able to discontinue feeding tube use; and 1 of 9 patients who required mechanical ventilation became able to breathe independently. In motor functional scales, improvements were observed in the 6-minute walk test performance in 7 of 8 subjects, Egen Klassifikation in 2 of 3, and North Star Ambulatory Assessment in all 5 tested. Baseline elevated serum growth differentiation factor 15 levels decreased with treatment in all 7 patients tested. A side effect observed in 8 of the 16 patients was dose-dependent diarrhea, which did not require withdrawal of treatment. Among 12 other TK2 patients treated with deoxynucleoside, 2 adults developed elevated liver enzymes that normalized following discontinuation of therapy.
INTERPRETATION
This open-label study indicates favorable side effect profiles and clinical efficacy of deoxynucleoside monophosphate and deoxynucleoside therapies for TK2 deficiency. ANN NEUROL 2019;86:293-303.
Topics: Adult; Child; Child, Preschool; Compassionate Use Trials; Deoxyribonucleosides; Female; Humans; Male; Muscular Diseases; Thymidine Kinase; Walk Test
PubMed: 31125140
DOI: 10.1002/ana.25506 -
Chemical Research in Toxicology Jun 2021The -alkylguanosine adduct -carboxymethyldeoxyguanosine (-CMdG) has been detected at elevated levels in blood and tissue samples from colorectal cancer patients and from...
The -alkylguanosine adduct -carboxymethyldeoxyguanosine (-CMdG) has been detected at elevated levels in blood and tissue samples from colorectal cancer patients and from healthy volunteers after consuming red meat. The diazo compound l-azaserine leads to the formation of -CMdG as well as the corresponding methyl adduct -methyldeoxyguanosine (-MedG) in cells and is therefore in wide use as a chemical probe in cellular studies concerning DNA damage and mutation. However, there remain knowledge gaps concerning the chemical basis of DNA adduct formation by l-azaserine. To characterize -CMdG formation by l-azaserine, we carried out a combination of chemical and enzymatic stability and reactivity studies supported by liquid chromatography tandem mass spectrometry for the simultaneous quantification of -CMdG and -MedG. We found that l-azaserine is stable under physiological and alkaline conditions as well as in active biological matrices but undergoes acid-catalyzed hydrolysis. We show, for the first time, that l-azaserine reacts directly with guanosine (dG) and oligonucleotides to form an -serine-CMdG (-Ser-CMdG) adduct. Moreover, by characterizing the reaction of dG with l-azaserine, we demonstrate that -Ser-CMdG forms as an intermediate that spontaneously decomposes to form -CMdG. Finally, we quantified levels of -CMdG and -MedG in a human cell line exposed to l-azaserine and found maximal adduct levels after 48 h. The findings of this work elucidate the chemical basis of how l-azaserine reacts with deoxyguanosine and support its use as a chemical probe for N-nitroso compound exposure in carcinogenesis research, particularly concerning the identification of pathways and factors that promote adduct formation.
Topics: Alkylation; Animals; Azaserine; Cells, Cultured; Deoxyguanosine; Humans; Hydrogen-Ion Concentration; Molecular Structure; Swine
PubMed: 34061515
DOI: 10.1021/acs.chemrestox.0c00471 -
Frontiers in Immunology 2022Adenosine synthase A (AdsA) is a key virulence factor of , a dangerous microbe that causes fatal diseases in humans. Together with staphylococcal nuclease, AdsA...
Adenosine synthase A (AdsA) is a key virulence factor of , a dangerous microbe that causes fatal diseases in humans. Together with staphylococcal nuclease, AdsA generates deoxyadenosine (dAdo) from neutrophil extracellular DNA traps thereby igniting caspase-3-dependent cell death in host immune cells that aim at penetrating infectious foci. Powered by a multi-technological approach, we here illustrate that the enzymatic activity of AdsA in abscess-mimicking microenvironments is not restricted to the biogenesis of dAdo but rather comprises excessive biosynthesis of deoxyguanosine (dGuo), a cytotoxic deoxyribonucleoside generated by to eradicate macrophages of human and animal origin. Based on a genome-wide CRISPR-Cas9 knock-out screen, we further demonstrate that dGuo-induced cytotoxicity in phagocytes involves targeting of the mammalian purine salvage pathway-apoptosis axis, a signaling cascade that is concomitantly stimulated by staphylococcal dAdo. Strikingly, synchronous targeting of this route by AdsA-derived dGuo and dAdo boosts macrophage cell death, indicating that multiplexes death-effector deoxyribonucleosides to maximize intra-host survival. Overall, these data provide unique insights into the cunning lifestyle of a deadly pathogen and may help to design therapeutic intervention strategies to combat multidrug-resistant staphylococci.
Topics: Animals; Deoxyadenosines; Mammals; Neutrophils; Staphylococcal Infections; Staphylococcus; Staphylococcus aureus
PubMed: 35355997
DOI: 10.3389/fimmu.2022.847171 -
Organic Letters Jul 2018The synthesis and characterization of a universal and fluorescent nucleoside, 4-cyanoindole-2'-deoxyribonucleoside (4CIN), and its incorporation into DNA is described....
The synthesis and characterization of a universal and fluorescent nucleoside, 4-cyanoindole-2'-deoxyribonucleoside (4CIN), and its incorporation into DNA is described. 4CIN is a highly efficient fluorophore with quantum yields >0.90 in water. When incorporated into duplex DNA, 4CIN pairs equivalently with native nucleobases and has uniquely high quantum yields ranging from 0.15 to 0.31 depending on sequence and hybridization contexts, surpassing that of 2-aminopurine, the prototypical nucleoside fluorophore. 4CIN constitutes a new isomorphic nucleoside for diverse applications.
Topics: DNA; Deoxyribonucleosides; Fluorescent Dyes; Indoles; Isomerism; Light; Nitriles; Nucleic Acid Hybridization
PubMed: 29989830
DOI: 10.1021/acs.orglett.8b01746 -
International Journal of Molecular... Oct 2022The lack of effective treatments for mitochondrial disease has seen the development of new approaches, including those that stimulate mitochondrial biogenesis to boost...
The lack of effective treatments for mitochondrial disease has seen the development of new approaches, including those that stimulate mitochondrial biogenesis to boost ATP production. Here, we examined the effects of deoxyribonucleosides (dNs) on mitochondrial biogenesis and function in Short chain enoyl-CoA hydratase 1 (ECHS1) 'knockout' (KO) cells, which exhibit combined defects in both oxidative phosphorylation (OXPHOS) and mitochondrial fatty acid β-oxidation (FAO). DNs treatment increased mitochondrial DNA (mtDNA) copy number and the expression of mtDNA-encoded transcripts in both CONTROL (CON) and ECHS1 KO cells. DNs treatment also altered global nuclear gene expression, with key gene sets including 'respiratory electron transport' and 'formation of ATP by chemiosmotic coupling' increased in both CON and ECHS1 KO cells. Genes involved in OXPHOS complex I biogenesis were also upregulated in both CON and ECHS1 KO cells following dNs treatment, with a corresponding increase in the steady-state levels of holocomplex I in ECHS1 KO cells. Steady-state levels of OXPHOS complex V, and the CIII/CIV and CI/CIII/CIV supercomplexes, were also increased by dNs treatment in ECHS1 KO cells. Importantly, treatment with dNs increased both basal and maximal mitochondrial oxygen consumption in ECHS1 KO cells when metabolizing either glucose or the fatty acid palmitoyl-L-carnitine. These findings highlight the ability of dNs to improve overall mitochondrial respiratory function, via the stimulation mitochondrial biogenesis, in the face of combined defects in OXPHOS and FAO due to ECHS1 deficiency.
Topics: Organelle Biogenesis; Enoyl-CoA Hydratase; DNA, Mitochondrial; Fatty Acids; Glucose; Carnitine; Deoxyribonucleosides; Adenosine Triphosphate
PubMed: 36293464
DOI: 10.3390/ijms232012610 -
Anaesthesia Aug 1987
Topics: Acquired Immunodeficiency Syndrome; Anesthesiology; Anesthetics; Antiviral Agents; Drug Interactions; Humans; Thymidine; Zidovudine
PubMed: 3477963
DOI: 10.1111/j.1365-2044.1987.tb04101.x -
The Yale Journal of Biology and Medicine Sep 2020The thyroid is not necessary to sustain life. However, thyroid hormones (TH) strongly affect the human body. Functioning of the thyroid gland affects the reproductive... (Review)
Review
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 (HO) is necessary. From the chemical point of view, TH is a reactive oxygen species (ROS) and serves as an oxidative stress (OS) promoter. HO 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.
Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Child; Deoxyguanosine; Female; Humans; Hydrogen Peroxide; Male; Pregnancy; Reactive Oxygen Species; Thyroid Diseases
PubMed: 33005115
DOI: No ID Found -
Molecules (Basel, Switzerland) Jun 2022An improved protocol for the transformation of ribonucleosides into 2',3'-dideoxynucleoside and 2',3'-didehydro-2',3'-dideoxynucleoside derivatives, including the...
An improved protocol for the transformation of ribonucleosides into 2',3'-dideoxynucleoside and 2',3'-didehydro-2',3'-dideoxynucleoside derivatives, including the anti-HIV drugs stavudine (d4T), zalcitabine (ddC) and didanosine (ddI), was established. The process involves radical deoxygenation of xanthate using environmentally friendly and low-cost reagents. Bromoethane or 3-bromopropanenitrile was the alkylating agent of choice to prepare the ribonucleoside 2',3'-bisxanthates. In the subsequent radical deoxygenation reaction, tris(trimethylsilyl)silane and 1,1'-azobis(cyclohexanecarbonitrile) were used to replace hazardous BuSnH and AIBN, respectively. In addition, TBAF was substituted for camphorsulfonic acid in the deprotection step of the 5'--silyl ether group, and an enzyme (adenosine deaminase) was used to transform 2',3'-dideoxyadenosine into 2',3'-dideoxyinosine (ddI) in excellent yield.
Topics: Anti-HIV Agents; Didanosine; Dideoxynucleosides; Stavudine; Zalcitabine; Zidovudine
PubMed: 35807233
DOI: 10.3390/molecules27133993 -
Redox Biology Jun 2021Oxidatively generated damage to DNA has been implicated in the pathogenesis of a wide variety of diseases. Increasingly, interest is also focusing upon the effects of...
Oxidatively generated damage to DNA has been implicated in the pathogenesis of a wide variety of diseases. Increasingly, interest is also focusing upon the effects of damage to the other nucleic acids, RNA and the (2'-deoxy-)ribonucleotide pools, and evidence is growing that these too may have an important role in disease. LC-MS/MS has the ability to provide absolute quantification of specific biomarkers, such as 8-oxo-7,8-dihydro-2'-deoxyGuo (8-oxodG), in both nuclear and mitochondrial DNA, and 8-oxoGuo in RNA. However, significant quantities of tissue are needed, limiting its use in human biomonitoring studies. In contrast, the comet assay requires much less material, and as little as 5 μL of blood may be used, offering a minimally invasive means of assessing oxidative stress in vivo, but this is restricted to nuclear DNA damage only. Urine is an ideal matrix in which to non-invasively study nucleic acid-derived biomarkers of oxidative stress, and considerable progress has been made towards robustly validating these measurements, not least through the efforts of the European Standards Committee on Urinary (DNA) Lesion Analysis. For urine, LC-MS/MS is considered the gold standard approach, and although there have been improvements to the ELISA methodology, this is largely limited to 8-oxodG. Emerging DNA adductomics approaches, which either comprehensively assess the totality of adducts in DNA, or map DNA damage across the nuclear and mitochondrial genomes, offer the potential to considerably advance our understanding of the mechanistic role of oxidatively damaged nucleic acids in disease.
Topics: 8-Hydroxy-2'-Deoxyguanosine; Biomarkers; Chromatography, Liquid; DNA Damage; Deoxyguanosine; Humans; Nucleic Acids; Oxidative Stress; Tandem Mass Spectrometry
PubMed: 33579665
DOI: 10.1016/j.redox.2021.101872