UDP-glucuronosyltransferases (UGTs) catalyze the glucuronidation of numerous endogenous and exogenous compounds to facilitate their excretion from the body. Because rats are commonly used in ...nonclinical studies, information regarding UGT species differences between rats and humans would be helpful for understanding human pharmacokinetics. In this study, we determined the absolute mRNA expressions of Ugt isoforms in the liver and small intestine of male and female Sprague-Dawley, Fischer 344, and Wistar rats. The sum of the mRNA levels of Ugt isoforms expressed in the liver was significantly (
< 0.005) higher than that in the small intestine regardless of the strain and sex. Ugt2b mRNA levels represented approximately 80% of total Ugt mRNA levels in the liver, whereas Ugt1a mRNA levels accounted for almost 90% in the small intestine. Ugt2b2 mRNA was specifically expressed in Wistar rat liver, resulting in 2-fold higher expression of total hepatic Ugt mRNA in Wistar rats than that in the other strains. Wistar rats showed prominently higher Ugt2b3 and Ugt2b8 mRNA levels in the small intestine than the other strains. The difference between sexes was remarkable with regard to hepatic Ugt1a10 in any of the strains, although slight differences between sexes were also observed in multiple Ugt isoforms. Taken together, this study revealed sex and strain differences in mRNA levels of rat Ugts. The data shown here would be useful for the selection of rat strains in nonclinical studies.
Glycosylation, the most common posttranslational modification of proteins, is a stepwise process that relies on tight regulation of subcellular glycosyltransferase location to control the addition of ...each monosaccharide. Glycosyltransferases primarily reside and function in the endoplasmic reticulum (ER) and the Golgi apparatus; whether and how they traffic beyond the Golgi, how this trafficking is controlled, and how it impacts glycosylation remain unclear. Our previous work identified a connection between N-glycosylation and Rab11, a key player in the post-Golgi transport that connects recycling endosomes and other compartments. To learn more about the specific role of Rab11, we knocked down Rab11 in HeLa cells. Our findings indicate that Rab11 knockdown results in a dramatic enhancement in the sialylation of N-glycans. Structural analyses of glycans using lectins and LC-MS revealed that α2,3-sialylation is selectively enhanced, suggesting that an α2,3-sialyltransferase that catalyzes the sialyation of glycoproteins is activated or upregulated as the result of Rab11 knockdown. ST3GAL4 is the major α2,3-sialyltransferase that acts on N-glycans; we demonstrated that the localization of ST3GAL4, but not the levels of its mRNA, protein, or donor substrate, was altered by Rab11 depletion. In knockdown cells, ST3GAL4 is densely distributed in the trans-Golgi network, compared with the wider distribution in the Golgi and in other peripheral puncta in control cells, whereas the α2,6-sialyltransferase ST6GAL1 is predominantly localized to the Golgi regardless of Rab11 knockdown. This indicates that Rab11 may negatively regulate α2,3-sialylation by transporting ST3GAL4 to post-Golgi compartments (PGCs), which is a novel mechanism of glycosyltransferase regulation.
Ubiquitination is a key post-translational modification in the regulation of numerous biological processes in eukaryotes. The primary roles of ubiquitination are thought to be the triggering of ...protein degradation and the regulation of signal transduction. During protein ubiquitination, substrate specificity is mainly determined by E3 ubiquitin ligase (E3). Although more than 600 genes in the human genome encode E3, the E3s of many target proteins remain unidentified owing to E3 diversity and the instability of ubiquitinated proteins in cell. We demonstrate herein a novel biochemical analysis for the identification of E3s targeting specific proteins. Using wheat cell-free protein synthesis system, a protein array containing 227 human and 23 mouse recombinant E3s was synthesized. To establish the high-throughput binding assay using AlphaScreen technology, we selected MDM2 and p53 as the model combination of E3 and its target protein. The AlphaScreen assay specifically detected the binding of p53 and MDM2 in a crude translation mixture. Then, a comprehensive binding assay using the E3 protein array was performed. Eleven of the E3s showed high binding activity, including four previously reported E3s (e.g., MDM2, MDM4, and WWP1) targeting p53. This result demonstrated the reliability of the assay. Another interactors, RNF6 and DZIP3-which there have been no report to bind p53-were found to ubiquitinate p53 in vitro. Further analysis showed that RNF6 decreased the amount of p53 in H1299 cells in E3 activity-dependent manner. These results suggest the possibility that the RNF6 ubiquitinates and degrades p53 in cells. The novel in vitro screening system established herein is a powerful tool for finding novel E3s of a target protein.
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Nitrazepam (NZP) is a hypnotic agent that rarely causes liver injuries in humans and teratogenicity in rodents. In humans, NZP is primarily metabolized to 7-aminonitrazepam (ANZP) by ...reduction and subsequently to 7-acetylamino nitrazepam (AANZP) by acetylation. ANZP can be regenerated from AANZP by hydrolysis in rodents, but it is still unclear whether this reaction occurs in humans. In rodents, AANZP may be associated with teratogenicity, while in humans, it is known that drug-induced liver injuries may be caused by NZP reactive metabolite(s). In this study, we attempted to identify the enzymes responsible for NZP metabolism to obtain a basic understanding of this process and the associated metabolite toxicities. We found that the NZP reductase activity in human liver cytosol (HLC) was higher than that in human liver microsomes (HLM). We purified the responsible enzyme(s) from HLC and found that the NZP reductase was aldehyde oxidase 1 (AOX1). The role of AOX1 was confirmed by an observed increase in the NZP reductase activity upon addition of N1-methylnicotinamide, an electron donor of AOX1, as well as inhibition of this activity in HLC in the presence of AOX1 inhibitors. ANZP was acetylated to form AANZP by N-acetyltransferase (NAT) 2. An experiment using recombinant esterases in an inhibition study using HLM revealed that AANZP is hydrolyzed by arylacetamide deacetylase (AADAC) in the human liver. N-Hydroxylamino NZP, which is suspected to be a reactive metabolite, was detected as a conjugate with N-acetyl-l-cysteine through NZP reduction and ANZP hydroxylation reactions. In the latter reaction, the conjugate was readily formed by recombinant CYP3A4 among the various P450 isoforms tested. In sum, we found that AOX1, NAT2, AADAC, and CYP3A4 are the determinants for the pharmacokinetics of NZP and that they confer interindividual variability in sensitivity to NZP side effects.
Obesity is associated with various complications and decreased life expectancy, and substantial heterogeneity in complications and outcomes has been observed. However, the subgroups of obesity have ...not yet been clearly defined. This study aimed to identify the subgroups of obesity especially those for target of interventions by cluster analysis.
In this study, an unsupervised, data-driven cluster analysis of 9,494 individuals with obesity (body mass index ≥ 35 kg/m
) was performed using the data of ICD-10, drug, and medical procedure from the healthcare claims database. The prevalence and clinical characteristics of the complications such as diabetes in each cluster were evaluated using the prescription records. Additionally, renal and life prognoses were compared among the clusters.
We identified seven clusters characterised by different combinations of complications and several complications were observed exclusively in each cluster. Notably, the poorest prognosis was observed in individuals who rarely visited a hospital after being diagnosed with obesity, followed by those with cardiovascular complications and diabetes.
In this study, we identified seven subgroups of individuals with obesity using population-based data-driven cluster analysis. We clearly demonstrated important target subgroups for intervention as well as a metabolically healthy obesity group.
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Human arylacetamide deacetylase (AADAC) hydrolyzes various drugs containing an acetyl group, such as ketoconazole and rifampicin. Knowledge about the role of human AADAC in drug ...metabolism is accumulating, but the regulatory mechanism of its expression has not been elucidated. In mice, it has been suggested that Aadac expression may be regulated by peroxisome proliferator-activated receptor α (Pparα). This study examined whether human AADAC is regulated by PPARα, which widely regulates the expression of lipid metabolism-related genes. In human hepatoma Huh-7 cells, AADAC mRNA and protein levels were significantly increased by treatment with fenofibric acid and WY-14643, PPARα ligands. Knockdown and overexpression of PPARα resulted in decreased and increased expression of AADAC, respectively. Luciferase assays revealed that the direct repeat 1 (DR1) at −193/−181 in the AADAC promoter region is responsible for transactivation by PPARα. Chromatin immunoprecipitation assays revealed the binding of PPARα to DR1. Thus, it was demonstrated that human AADAC is regulated by PPARα through binding to DR1. Oil red O staining showed that overexpression of AADAC in Huh-7 cells suppressed lipid accumulation after treatment with free fatty acids. The suppression was restored by treatment with diisopropyl fluorophosphate, an AADAC inhibitor. The WY-14643-mediated suppression of lipid accumulation was restored by AADAC knockdown. These results suggested that AADAC has a role in suppressing cellular lipid accumulation. In conclusion, this study demonstrated the regulation of human AADAC by PPARα and its significance in lipid accumulation.
The Intergovernmental Panel on Climate Change recommends keeping the increase in temperature to less than a two-degree increase by the end of the century, but the direct impact of global warming on ...ecosystems including microbes has not been investigated. Here we performed thermal adaptation of two species and three strains of mesophilic microbes for improvement of the survival upper limit of temperature, and the improvement was evaluated by a newly developed method. To understand the limitation and variation of thermal adaptation, experiments with mutators and by multiple cultures were performed. The results of experiments including genome sequencing and analysis of the characteristics of mutants suggest that these microbes bear a genomic potential to endure a 2-3°C rise in temperature but possess a limited variation of strategies for thermal adaptation.
Objective: Assessments of diurnal awake bruxism (d-AB) using masseteric electromyogram (EMG) during various lengths of measurement time within a day were examined as the first step of research to ...clarify the minimum measurement time required for assessment of d-AB by subject.
Methods: Subjects were 33 outpatients. Assessment of d-AB by EMG during partial measurement time (PMT) with durations ranging from 30 minutes to 6 hours was compared with that during total measurement time (TMT) used as the reference standard.
Results: No significant difference was found between TMT data and PMT data. There were significant correlations in all combinations between TMT data and PMT data. Accuracy was 0.909 or more for 2.5 hours or longer.
Discussion: The results suggest that the tendency of daytime muscle activity in 1 day can be assessed even by using masseteric EMG data obtained during a relatively short measurement time.
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