👤 Gaku Morinaga

Enzymes catalyzing the reduction reaction of xenobiotics are mainly members of the aldo-keto reductase (AKR) and short-chain dehydrogenase/reductase (SDR) superfamilies. The intestine, together with the liver, is responsible for first-pass effects and is an organ that determines the bioavailability of orally administered drugs. In this study, we evaluated the mRNA and protein expression levels of 12 AKR isoforms (AKR1A1, AKR1B1, AKR1B10, AKR1B15, AKR1C1, AKR1C2, AKR1C3, AKR1C4, AKR1D1, AKR1E2, AKR7A2, and AKR7A3) and 7 SDR isoforms (CBR1, CBR3, CBR4, DCXR, DHRS4, HSD11B1, and HSD17B12) in each region of the human intestine using next-generation sequencing and data-independent acquisition proteomics. At both the mRNA and protein levels, most AKR isoforms were highly expressed in the upper regions of the intestine, namely the duodenum and jejunum, and then declined toward the rectum. Among the members in the SDR superfamily, CBR1 and DHRS4 were highly expressed in the upper regions, whereas the expression levels of the other isoforms were almost uniform in all regions. Significant positive correlations between mRNA and protein levels were observed in AKR1A1, AKR1B1, AKR1B10, AKR1C3, AKR7A2, AKR7A3, CBR1, and CBR3. The mRNA level of AKR1B10 was highest, followed by AKR7A3 and CBR1, each accounting for more than 10% of the sum of all AKR and SDR levels in the small intestine. This expression profile in the human intestine was greatly different from that in the human liver, where AKR1C isoforms are predominantly expressed. SIGNIFICANCE STATEMENT: In this study comprehensively determined the mRNA and protein expression profiles of aldo-keto reductase (AKR) and short-chain dehydrogenase/reductase isoforms involved in xenobiotic metabolism in the human intestine and found that most of them are highly expressed in the upper region, where AKR1B10, AKR7A3, and CBR1 are predominantly expressed. Since the intestine is significantly involved in the metabolism of orally administered drugs, the information provided here is valuable for pharmacokinetic studies in drug development. Show less

Nabumetone, a nonsteroidal anti-inflammatory prodrug, is converted to a pharmacologically active metabolite, 6-methoxy-2-naphthylacetic acid (6-MNA); however, it is 11-fold more efficiently converted to 4-(6-methoxy-2-naphthyl)butan-2-ol (MNBO) via a reduction reaction in human hepatocytes. The goal of this study was to identify the enzyme(s) responsible for MNBO formation from nabumetone in the human liver. MNBO formation by human liver microsomes (HLM) was 5.7-fold higher than in the liver cytosol. In a panel of 24 individual HLM samples with quantitative proteomics data, the 17β-hydroxysteroid dehydrogenase 12 (HSD17B12) protein level had the high correlation coefficient (r = 0.80, P < 0.001) among 4457 proteins quantified in microsomal fractions during MNBO formation. Recombinant HSD17B12 expressed in HEK293T cells exhibited prominent nabumetone reductase activity, and the contribution of HSD17B12 to the activity in the HLM was calculated as almost 100%. MNBO formation in HepG2 and Huh7 cells was significantly decreased by the knockdown of HSD17B12. We also examined the role of HSD17B12 in drug metabolism and found that recombinant HSD17B12 catalyzed the reduction reactions of pentoxifylline and S-warfarin, suggesting that HSD17B12 prefers compounds containing a methyl ketone group on the alkyl chain. In conclusion, our study demonstrated that HSD17B12 is responsible for the formation of MNBO from nabumetone. Together with the evidence for pentoxifylline and S-warfarin reduction, this is the first study to report that HSD17B12, which is known to metabolize endogenous compounds, such as estrone and 3-ketoacyl-CoA, plays a role as a drug-metabolizing enzyme. Show less

Na Knockdown of ATP1A1 expression was performed in human CC cell lines HT29 and Caco2 using small interfering RNA. The roles of ATP1A1 in various biological processes of cells (i.e., proliferation, cell cycle, apoptosis, migration, and invasion) were assessed. Microarray analysis was utilized for gene expression profiling. Samples obtained from 200 patients with CC who underwent curative colectomy were analyzed through immunohistochemistry. ATP1A1 knockdown suppressed cell proliferation, migration, and invasion and induced apoptosis. The results of the microarray analysis revealed that the upregulated or downregulated gene expression in ATP1A1-depleted cells was related to the extracellular signal-regulated kinase 5 (ERK5) signaling pathway [epidermal growth factor receptor (EGFR), mitogen-activated protein kinase kinase 5 (MAP2K5), mitogen-activated protein kinase 7 (MAPK7), FOS, MYC, and BCL2 associated agonist of cell death (BAD)]. Immunohistochemical analysis demonstrated a correlation between ATP1A1 expression and pathological T stage (p = 0.0054), and multivariate analysis identified high ATP1A1 expression as an independent predictor of poor recurrence-free survival in patients with CC (p = 0.0040, hazard ratio: 2.807, 95% confidence interval 1.376-6.196). ATP1A1 regulates tumor progression through the ERK5 signaling pathway. High ATP1A1 expression is associated with poor long-term outcomes in patients with CC. Show less

Angiopoietin-like proteins (ANGPTLs) 3, 4, and 8 reportedly contribute to progression of metabolic disease, a risk factor for cardiovascular disease (CVD). The purpose of this study was to investigate whether circulating ANGPTL levels are associated with CVD risk after adjustment for potential confounding factors. We conducted a single center, cross-sectional study of 988 Japanese subjects undergoing routine health checks. Serum ANGPTL3, 4, and 8 levels were measured using an enzyme-linked immunosorbent assay. Using multiple regression analysis we evaluated potential association of circulating ANGPTL3, 4, and 8 levels with general medical status including age, sex, smoking, drinking, obesity, hypertension, impaired glycometabolism, dyslipidemia, hyperuricemia, hepatic impairment, chronic kidney disease, anemia, cardiac abnormality, and inflammation. Circulating ANGPTL3 levels were relatively high in health-related categories of hepatic impairment and inflammation. Circulating ANGPTL4 levels were also significantly high in impaired glycometabolism or hepatic impairment but decreased in inflammation. Finally, increased ANGPTL8 levels were observed in obesity, impaired glycometabolism and dyslipidemia. Particularly, increased levels of circulating ANGPTL8 were positively correlated with circulating triglycerides and LDL-cholesterol levels and inversely correlated with circulating HDL-cholesterol levels. Circulating ANGPTL3, 4, and 8 levels reflect some risk factors for CVD development. Show less

Oxidative stress is involved in the progression of non-alcoholic steatohepatitis (NASH). However, there are few biomarkers that are easily measured and accurately reflect the disease states. The aim of this study was to identify novel oxidative stress markers using the 2-nitrobenzenesulfenyl (NBS) stable isotope labeling method and to examine the clinical utility of these diagnostic markers for NASH. Proteins extracted from phosphate buffered saline- and hydrogen peroxide-loaded human primary hepatocyte were labeled with the [(12)C]- and [(13)C]-NBS reagents, respectively. Pairs of peaks with 6-Da differences in which the [(13)C]-NBS labeling was more intense than the [(12)C]-NBS labeling were detected by MALDI-TOF/MS and identified by MS/MS ion searching. Four pairs of peaks, m/z 1705-1711, m/z 1783-1789, m/z 1902-1908 and m/z 2790-2796, were identified as cytochrome c oxidase VIb (COX6B), liver carboxylesterase 1 (CES1), carbamoyl-phosphate synthase 1 (CPS1) and superoxide dismutase (MnSOD), respectively. Furthermore, serum MnSOD protein levels were significantly higher in NASH patients than in simple steatosis (SS) patients. The serum MnSOD levels tended to increase in parallel with the stage of fibrosis. The NBS labeling technique was useful to identify biomarkers. Serum MnSOD may be a useful biomarker that can distinguish between SS and NASH. Show less