Mammalian enzymes for preventing transcriptional errors caused by oxidative damage

Biomolecular Engineering Research Institute Suita, Osaka 565-0874, Japan.
Nucleic Acids Research (Impact Factor: 9.11). 02/2005; 33(12):3779-84. DOI: 10.1093/nar/gki682
Source: PubMed

ABSTRACT 8-Oxo-7,8-dihydroguanine (8-oxoGua) is produced in cells by reactive oxygen species normally formed during cellular metabolic processes. This oxidized base can pair with both adenine and cytosine, and thus the existence of this base in messenger RNA would cause translational errors. The MutT protein of Escherichia coli degrades 8-oxoGua-containing ribonucleoside di- and triphosphates to the monophosphate, thereby preventing the misincorporation of 8-oxoGua into RNA. Here, we show that for human the MutT-related proteins, NUDT5 and MTH1 have the ability to prevent translational errors caused by oxidative damage. The increase in the production of erroneous proteins by oxidative damage is 28-fold over the wild-type cells in E.coli mutT deficient cells. By the expression of NUDT5 or MTH1 in the cells, it is reduced to 1.4- or 1.2-fold, respectively. NUDT5 and MTH1 hydrolyze 8-oxoGDP to 8-oxoGMP with V(max)/K(m) values of 1.3 x 10(-3) and 1.7 x 10(-3), respectively, values which are considerably higher than those for its normal counterpart, GDP (0.1-0.5 x 10(-3)). MTH1, but not NUDT5, possesses an additional activity to degrade 8-oxoGTP to the monophosphate. These results indicate that the elimination of 8-oxoGua-containing ribonucleotides from the precursor pool is important to ensure accurate protein synthesis and that both NUDT5 and MTH1 are involved in this process in human cells.

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    • "NUDT5, which was down-regulated in TNF-␣-treated JMJD3- kd THP-1 cells, has an important role in the hydrolysis of 8-oxo guanosine diphosphate to 8-oxo guanosine monophosphate and therefore prevention of misincorporation of 8-oxo guanosine into RNA. The 8-oxo guanosine containing nucleotides can be incorporated into RNA or DNA, which can cause transcriptional and replicational errors, respectively (Ishibashi et al., 2005). In addition , recently, Zhang et al. (2012) reported that the cell cycle G1 phase was significantly delayed and that the cell numbers in both S and G2/M phases were reduced by NUDT5 suppression through induction of key proteins that prevent the G1-S transition, including p53, p16 and Rb. "
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    ABSTRACT: JMJD3, a Jumonji C family histone demethylase, plays an important role in the regulation of inflammation induced by the transcription factor nuclear factor-kappa B (NF-κB) in response to various stimuli. JMJD3 is a histone-3 lysine-27 trimethylation (H3K27me3) demethylase, a histone mark associated with transcriptional repression and activation of a diverse set of genes. The present study assessed stable JMJD3 knockdown (KD)-dependent proteomic profiling in human leukemia monocyte (THP-1) cells to analyze the JMJD3-mediated differential changes of marker expression in inflammatory cells. To analyze the protein expression profile of tumor necrosis factor-alpha (TNF-α)-stimulated JMJD3-kd THP-1 cells, we employed matrix-assisted-laser-desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Additionally, Ingenuity Pathways Analysis (IPA) was applied to establish the molecular networks. A comparative proteomic profile was determined in TNF-α-treated both of JMJD3-kd THP-1 cells and THP-1 scrambled (sc) cells. The expression of tripartite motif protein (TRIM5), glutathione peroxidase (GPx), glia maturation factor-γ (GMFG), caspase recruitment domain family, member 14 (CARMA2), and dUTP pyrophosphatase were significantly down-regulated, whereas heat shock protein beta-1 (HspB1) and prohibition were significantly up-regulated in JMJD3-kd THP-1 cells. The molecular and signaling networks of the differentially expressed proteins in JMJD3-kd THP-1 cells were determined by IPA. The molecular network signatures and functional proteomics obtained in this study may facilitate the suppression of different key inflammatory regulators through JMJD3-attenuation, which would be crucial to evaluate potential therapeutic targets and to elucidate the molecular mechanism of JMJD3-kd dependent effects in THP-1 cells.
    Molecular Immunology 05/2013; 56(1-2):113-122. DOI:10.1016/j.molimm.2013.04.013 · 3.00 Impact Factor
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    • "MutT protein in Escherichia coli and its mammalian homologues MutT homologue 1 (MTH1) and Nudix type 5 (NUDT5) proteins participate in this error-avoiding mechanism by hydrolyzing the oxidized nucleoside diphosphates and/or triphosphates to the monophosphates (Taddei et al. 1997; Hayakawa et al. 1999; Nakabeppu et al. 2004, 2006; Ishibashi et al. 2005; Ito et al. 2005). Indeed, the increase in the production of erroneous proteins by oxidative damage is 28-fold over the wild type cells in Escherichia coli mutT deficient cells, which is reduced to 1.2-or 1.4-fold by the expression of MTH1 or NUDT5, respectively (Ishibashi et al. 2005). Correspondingly, MTH1 deficiency augments the RNA oxidation induced by kainic acid treatment in MTH1-null mouse (Kajitani et al. 2006). "
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    ABSTRACT: An age-associated increase in oxidative damage to nucleic acids, predominantly to RNA, has been recently demonstrated in neurons of human and rodent brains, which may play a fundamental role in the development of age-associated neurodegeneration. Indeed, more prominent levels of neuronal RNA oxidation compared to normal aging have been described in neurodegenerative disorders including Alzheimer disease, Parkinson disease, dementia with Lewy bodies, and amyotrophic lateral sclerosis. Moreover, oxidative damage to RNA has been found also in cellular and animal model of neurodegeneration. Oxidative RNA modification can occur not only in protein-coding RNAs but also in non-coding RNAs that are recently revealed to contribute towards the complexity of the mammalian brain. It has been hypothesized that RNA oxidation causes aberrant expression of microRNAs and proteins and subsequently initiates inappropriate cell fate pathways. While less lethal than mutations in the genome and not inheritable, such sublethal damage to cells might be associated with underlying mechanisms of degeneration, especially age-associated neurodegeneration. Of particular interest, the accumulating evidence obtained from studies on either human samples or experimental models coincidentally suggests that RNA oxidation is a feature in neurons of aging brain and more prominently observed in vulnerable neurons at early-stage of age-associated neurodegenerative disorders, indicating that RNA oxidation actively contributes to the background, the onset, and the development of the disorders. Further investigations aimed at understanding of the processing mechanisms related to oxidative RNA damage and its consequences may provide significant insights into the pathogenesis of neurodegenerative disorders and lead to better therapeutic strategies.
    Neurotoxicity Research 06/2012; 22(3):231-48. DOI:10.1007/s12640-012-9331-x · 3.15 Impact Factor
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    • "Malondialdehyde, a potentially cytotoxic lipid peroxidation breakdown product, is known to accumulate in a range of disorders including bullous keratopathy, keratoconus, diabetic retinopathy and retinitis pigmentosa (Buddi et al. 2002; Johnsen-Soriano et al. 2008). DNA damage may act to destabilize cell function through an increased level of transcriptional errors (Ishibashi et al. 2005). Although some increase after EBOC was observed, we found a downregulation of p53, a sensor for cell and DNA damage and effector of cell cycle arrest and also of apoptosis. "
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    ABSTRACT: Purpose Storage time for donor corneas in Optisol GS is limited compared to Eye Bank Organ Culture (EBOC). We here examine the epithelium on donor corneoscleral rims after primary storage in Optisol GS and subsequent incubation in EBOC. Methods Morphology was monitored by light and electron microscopy, expression of phenotypic and genotypic markers by immunohistochemistry and RT-PCR and changes in oxidative lipid and DNA damage by ELISA and COMET assay. Results A prominent loss of cells was observed after storage in Optisol GS. After maintenance in EBOC, spreading apical cells were Occludin+, while the staining for E-cadherin and Connexin-43 was less intense. There were an upregulation of Occludin and a downregulation of E-cadherin and Connexin-43. Eye Bank Organ Culture was associated with an ongoing proliferative activity and a downregulation of putative progenitor/stem cell marker ABCG2 and p63. Staining for 8-OHdG and Caspase-3 did not increase, while levels of malondialdehyde and number of DNA strand breaks and oxidized bases increased. Conclusions This dual procedure should be pursued as an option to increase the storage time and the pool of available donor corneas. The observed downregulation of markers associated with stemness during EBOC is relevant considering the potential use of donor epithelium in the treatment of ocular surface disorders.
    Acta ophthalmologica 03/2012; 91(3). DOI:10.1111/j.1755-3768.2012.02390.x · 2.51 Impact Factor
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