Project description:To investigate selectivity of mRNA oxidation, total RNA and oxidized RNA isolated from Neuro 2a cells before and after H2O2 treatment were employed for microarray analysis. It was found that selective oxidation of mRNA already occurs under normal culture conditions but was increased by H2O2, especially in a subset of mRNAs related to certain functions. Moreover, mRNA oxidation level is also related to its abundance or stability (half-life time). This shows for the first time that mRNA oxidation is associated with RNA homeostasis including function, stability and abundance depending on cellular redox status in a genome-wide scale.
Project description:To investigate selectivity of mRNA oxidation, total RNA and oxidized RNA isolated from Neuro 2a cells before and after H2O2 treatment were employed for microarray analysis. It was found that selective oxidation of mRNA already occurs under normal culture conditions but was increased by H2O2, especially in a subset of mRNAs related to certain functions. Moreover, mRNA oxidation level is also related to its abundance or stability (half-life time). This shows for the first time that mRNA oxidation is associated with RNA homeostasis including function, stability and abundance depending on cellular redox status in a genome-wide scale. Neuro 2a cells received hydrogen peroxide treatment or no treatment as a control. Samples were applied for RNA extraction and ARP labeling, which could bind with apurinic/apyrimidinic sites, and then a pull-down process to isolate oxidized RNA. Total RNA and oxidized RNA were used for subsequent transcriptomic profiling. 4 types of samples were analyzed: Basal-total: untreated N2a cells labeled with ARP, but not processed for the pull-down assay. Ox-total: hydrogen peroxide-treated N2a cells labeled with ARP, but not processed for the pull-down assay. Basal-ARP: untreated N2a cells labeled with ARP, and processed for the pull-down assay. ARP-derivatized RNA, which is also oxidized RNA, was concentrated and used for the microarray analysis. Ox-ARP: hydrogen peroxide-treated N2a cells labeled with ARP, and processed for the pull-down assay. ARP-derivatized RNA, which is also oxidized RNA, was concentrated and used for the microarray analysis.
Project description:RNA is more vulnerable to oxidation than other cellular components, which is linked to a range of diseases and pathological conditions, such as AKI. To identify the contribution of RNA oxidation to AKI, the mechanisms of how cells handle oxidized RNA should be elucidated. By RNA sequencing analysis in ischemia/reperfusion-induced AKI, we observed the significant changes of genes important in degradingting oxidative RNA.
Project description:By relating the numbers of oxidized guanines in different sequence contexts to the abundance of these contexts in the human genome, we observed that the probability of guanine to be or remain oxidized is low if this guanine is preceded by cytosine (CpG sites) compared to other nucleotides. As CpG sites are substrates of epigenetic cytosine methylation, we investigated the influence of cytosine methylation status on guanine oxidation level in CpG sites. For this, we exposed HAP1 and U2OS cells for three days to GSK-3484862, a novel DNA methyltransferase 1 (DNMT1) inhibitor causing the degradation of this enzyme within 24 hours and having low cellular toxicity. Using Infinium MethylationEPIC v2.0 array, we observed a drastic hypomethylation after the exposure in both cell lines such that the peak of highly methylated CpG sites (beta values 0.8–1) found in vehicle (DMSO) exposed cells is absent in GSK-3484862-exposed cells. In contrast, the oxidation level of guanines in the CpG sites profiled by the array did not change in response to the inhibitor and was virtually constant across CpG sites with different methylation levels. In addition, on the level of all CpG sites in the genome, guanine-oxidation did not differ between DMSO and GSK-3484862 exposures. Thus, in CpG sites, guanine oxidation level likely does not depend on cytosine methylation status. As a control for the click-code-seq protocol, we successfully called 8-oxoG incorporated at specific sites in a plasmid (~25 fmol) that was mixed with ~28-times bigger amount of the unmodified vector. As a control for click-code-seq detection of abasic sites, we inserted uracils in a plasmid, converted them to abasic sites by uracil-DNA glycosylase (UDG) and successfully called them in the expected locations.