Proteomic analysis for the impact of hypercholesterolemia on expressions of hepatic drug transporters and metabolizing enzymes.

1. Our objective is to investigate the alterations of hepatic drug transporters and metabolizing enzymes in hypercholesterolemia. Male Sprague-Dawley rats were fed high-cholesterol chows for 8 weeks to induce hypercholesterolemia. Protein levels of hepatic drug transporters and metabolizing enzymes were analyzed by iTRAQ labeling coupled with LC TRIPLE-TOF. 2. Total 239 differentially expressed proteins were identified using proteomic analysis. Among those, protein levels of hepatic drug transporters (MRP2, ABCD3, OAT2, SLC25A12, SCL38A3, SLC2A2 and SLC25A5) and metabolizing enzymes (CYP2B3, CYP2C7, CYP2C11, CYP2C13, CYP4A2 and UGT2B) were markedly reduced, but the levels of CYP2C6 and CYP2E1 were increased in hypercholesterolemia group compared to control. Decreased expressions of drug transporters MRP2 and OAT2 were further confirmed by real time quantitative PCR (RT-qPCR) and western blot. 3. Ingenuity pathway analysis revealed that these differentially expressed proteins were regulated by various signaling pathways including nuclear receptors and inflammatory cytokines. One of the nuclear receptor candidates, liver X receptor alpha (LXRα), was further validated by RT-qPCR and western blot. Additionally, LXRα agonist T0901317 rescued the reduced expressions of MRP2 and OAT2 in HepG2 cells in hypercholesterolemic serum treatment. 4. Our present results indicated that hypercholesterolemia affected the expressions of various drug transporters and metabolizing enzymes in liver via nuclear receptors pathway. Especially, decreased function of LXRα contributes to the reduced expressions of MRP2 and OAT2.

Time-dependent inhibition of CYP3A4 by gallic acid in human liver microsomes and recombinant systems.

1.Gallic acid is a main polyphenol in various fruits and plants. Inhibitory characteristics of gallic acid on CYP3A4 were still unclear. The objective of this work is hence to investigate inhibitory characteristics of gallic acid on CYP3A4 using testosterone as the probe substrate in human liver microsomes (HLMs) and recombinant CYP3A4 (rCYP3A4) systems. 2.Gallic acid caused concentration-dependent loss of CYP3A4 activity with IC50 values of 615.2 µM and 669.5 µM in HLM and rCYP3A4 systems, respectively. IC50-shift experiments showed that pre-incubation with gallic acid in the absence of NADPH contributed to 12- or 14-fold reduction of IC50 in HLM and rCYP3A4 systems, respectively, supporting a time-dependent inhibition. In HLM, time-dependent inactivation variables KI and Kinact were 485.8 µM and 0.05 min(-1), respectively. 3.Compared with the presence of NADPH, pre-incubation of gallic acid in the absence of NADPH markedly increased its inhibitory effects in HLM and rCYP3A4 systems. Those results indicate that CYP3A4 inactivation by gallic acid was independent on NADPH and was mainly mediated its oxidative products. 4.In conclusion, we showed that gallic acid weakly and time-dependently inactivated CYP3A4 via its oxidative products.

Efficacy and Safety of Vonoprazan-Based versus Proton Pump Inhibitor-Based Triple Therapy for Helicobacter pylori Eradication: A Meta-Analysis of Randomized Clinical Trials.

AIMS: To compare the efficacy and safety of vonoprazan-based versus proton pump inhibitor (PPI)-based triple therapy in the eradication of Helicobacter pylori. METHODS: We performed a systematic search in PubMed, Embase, and the Cochrane Library databases for relevant randomized controlled trials up to March 2019. Studies were included if they compared the efficacy and safety of H. pylori eradication of vonoprazan-based and PPI-based triple therapy. RESULTS: Three studies with 897 patients were evaluated in this meta-analysis. The H. pylori eradication rate of vonoprazan-based triple therapy was higher than that of PPI-based triple therapy as first-line regimens (intention-to-treat analysis: pooled eradication rates, 91.4% vs 74.8%; odds ratio [OR], 3.68; 95% confidence interval (CI): [1.87-7.26]; P<0.05). The incidence of adverse events in vonoprazan-based triple therapy was lower than that in PPI-based triple therapy (pooled incidence, 32.7% vs 40.5%; OR, 0.71; 95%CI: [0.53-0.95]; P<0.05). CONCLUSIONS: Efficacy of vonoprazan-based triple therapy is superior to that of PPI-based triple therapy for first-line H. pylori eradication. Additionally, vonoprazan-based triple therapy is better tolerated than PPI-based triple therapy.

Bibliometric analysis of the top-cited articles on islet transplantation.

AIMS: To identify and characterize the top-cited articles in the field of islet transplantation. METHODS: We used the Science Citation Index Expanded database to identify the most frequently cited articles published after 1900. Articles were evaluated using the following characteristics: citation number, publication year, study design, references, country and institution of origin, authorship, and journal. Keyword analysis and citation networks were used to analyze research trends. RESULTS: The most frequently cited articles received between 146 and 2988 citations; the median was 291. All of the most frequently cited articles were published between 1972 and 2012, and 85 articles were published after 1990. The most popular study design involved basic science (75 articles). The leading countries were the United States (US) and Canada, and the leading institutions were the University of Alberta, Canada, and the University of Minnesota, in the US. Journals specializing in diabetes or transplantation published more than half of the articles (n = 53, 52%), with the journal Diabetes publishing the largest number (n = 30). No association was found between a journal's impact factor and the number of top-cited articles it published. There was no correlation between the number of citations and the number of years since publication, authors, participating institutions, or countries involved. Top-cited articles focused on 2 themes: the use of antirejection immunotherapy or biocompatible encapsulations to prolong graft survival, and assessments of the efficacy of islet transplants, in particular, islet allografts. CONCLUSIONS: Our study can help researchers to identify and decipher the characteristics of top-cited articles in the field of islet transplantation. Just as clinically successful allografts are carried out using the Edmonton protocol, autografts and xenografts should be similarly strengthened to solve problems relating to immune rejection and islet sources, respectively.

Bibliometric analysis of scientific publications in transplantation journals from Mainland China, Japan, South Korea and Taiwan between 2006 and 2015.

OBJECTIVES: The aim of this study is to compare the quantity and quality of scientific publications in transplantation fields that were written by researchers from Mainland China, Japan, South Korea and Taiwan in the East Asia region. SETTINGS: East Asia. PARTICIPANTS AND OUTCOME MEASURES: Articles except editorials, conference abstracts, letters, news and corrections published in 25 transplantation journals from 2006 to 2015 were screened with the Web of Science database. The number of total and annual articles, article types (study design and transplantation site), impact factor, citations and articles in the high-impact journals was determined to assess the quantity and quality of transplantation research from East Asia. The correlation of socioeconomic factors and annual publications was also analysed. RESULTS: From 2006 to 2015, there were 47 141 articles published in transplantation journals, of which researchers from Japan published 3694 articles, followed by Mainland China, South Korea and Taiwan with 2778, 1643 and 951 articles, respectively. Similar trends were observed in accumulated impact factor, accumulated citations, articles in the high-impact journals and articles on transplantation site. Publications from Japan had the highest average impact factor and citation, while those from Mainland China had the lowest. Additionally, in terms of study design, authors from Mainland China contributed to most clinical trials and randomised controlled trials, but authors from Japan contributed to most case reports. The annual numbers of articles from Mainland China and South Korea increased linearly (p<0.05), but those from Japan and Taiwan remained stable for the period studied. The annual numbers of articles from Mainland China and South Korea were positively correlated with gross domestic product (p<0.05). CONCLUSIONS: Transplantation research productivity in East Asia is highly skewed, with gross domestic product having a significant positive correlation. Mainland China still lags far behind Japan in most bibliometric indicators; thus, there is vast room for improvement.

iTRAQ-based proteomic analysis of tetramethylpyrazine inhibition on lipopolysaccharide-induced microglial activation.

AIMS: Neurodegenerative diseases are the leading cause of morbidity and mortality worldwide. Several studies have shown that tetramethylpyrazine (TMP) is an effective therapy for neurodegenerative diseases and that it acts by inhibiting the activation of microglial cells in response to inflammatory stimuli. However, the molecular mechanisms underlying the action of TMP remain unknown. MAIN METHODS: Proteomic analysis was used to generate novel insights into the mechanism by which TMP inhibits microglial activation, and western blotting was used to validate candidate proteins. KEY FINDINGS: To identify candidate proteins affected by TMP in lipopolysaccharide-activated microglia, we performed proteomic analysis using iTRAQ labelling coupled with LC TRIPLE-TOF, and we identified 5187 unique proteins. Among these, 266 proteins were differentially expressed and considered putative candidate proteins. Protein annotation revealed that the differentially expressed proteins, such as inducible nitric oxide synthase (iNOS) and ERO1-like protein (ERO1L), might be involved in reducing cellular oxidation in response to stress. Ingenuity pathway analysis revealed that the differentially expressed proteins were involved in a variety of signalling pathways, including liver X receptor/retinoid X receptor (LXR/RXR) activation and the production of nitric oxide and reactive oxygen species in macrophages. Furthermore, one of the differentially expressed protein candidates detected by iTRAQ, iNOS, was confirmed by western blotting. SIGNIFICANCE: Our data suggest that iTRAQ technology is an effective tool to study the mechanism by which TMP inhibits activated microglia. TMP decreased the expression of LXR/RXR-mediated iNOS, which reduced microglial activation in response to inflammatory stimuli.