Latest ArticlesCytochrome P4502J2 (CYP2J2) is widely distributed in various human tissues and takes a part in the metabolism of endogenous compounds and drugs. CYP2J2 can convert arachidonic acid (AA) to expoxyeicosatrienoic acids (EETs), which have various biological effects, implying the important role of CYP2J2 in the regulation of cardiovascular system and promotion of tumor progression and metastasis. Additionally, CYP2J2 plays an indispensable role in the intestinal metabolism of various drugs, such as astemizole, terfenadine and ebastine. In this review, the metabolic function, characteristic of catalysis and tissue distribution of CYP2J2 are discussed with the latest literatures both in China and abroad. The state-of-the-art methods for characterization of CYP2J2 and current trend of substrate discovery as well as its relationship with disease are highlighted. This review gives in-depth understanding of the function of CYP2J2 and its role in disease advance. The information of ligand (substrate and inhibitor) will provide the theoretical guidance and reference to the development of novel drugs for CYP2J2.
P-glycoprotein (P-gp), an ATP binding cassette protein, plays a major role in efflux transport of drugs and xenobiotics due to its abundant expression on several barriers. This study aimed to investigate the potential role of PKC/NF-κB-PXR signaling pathway in modulation of P-gp gene expression in human colon adenocarcinoma LS174T. The effect of PMA on MDR1 luciferase activity was investigated by PXR-MDR1 dual luciferase reporter gene assay. Real-time qPCR assay and Western blot analysis were used to study the gene expression of P-gp and NF-κB, respectively. Compared to the vehicle-treated group, PMA statistically decreased P-gp luciferase activity, mRNA expression and protein expression. Moreover, PMA treatment yielded a significant and dose-dependent increase in RelA/p65 translocation to nucleus. Meanwhile, a remarkable increase of the pho-IκBα status was observed in LS174T cells after treatment with PMA (1-100 nmol·L-1). In addition, knockdown of PKCα, NF-κB or PXR can significantly attenuate PMA-induced P-gp suppression.These results suggested that PKC/NF-κB-PXR signaling pathway might play crucial roles in modulation of P-gp gene expression.
As important constituents of the first-line of host defense barrier, intestinal cytochrome P450 3A (CYP3A) and P-glycoprotein (P-gp) play important roles in disease pathogenesis as well as drug absorption and exposure. Clinical reports and experimental data revealed diminished intestinal CYP3A and P-gp expression accompanying with gut dysbiosis in inflammatory bowel disease. Yet whether gut dysbiosis is associated with the down-regulation of CYP3A and P-gp and the underlying mechanisms are unclear. In this study, daily administration of fresh feces from normal rats and rats with ulcerative colitis (UC) induced by dextran sulfate sodium to normal rats resulted in alterations of gut bacterial compositions. Intestinal CYP3A2 and P-gp were significantly down-regulated in rats receiving UC feces. Outer-membrane vesicles (OMVs) are nano-scale special buds of the outer membrane which are produced by Gram-negative bacteria and mediate diverse functions including interactions within bacterial communities and communications with host. Expressions of CYP3A4 and P-gp mRNA were diminished in human epithelial colorectal adenocarcinoma cells (Caco-2) treated by OMVs from all different groups with OMVs from UC rats or rats receiving UC feces showing more significant effects.Moreover, the OMVs fractions within 30 000-50 000 Daltons from both normal and UC rats elicited more effects than fractions of other molecular weights. Treatment of Caco-2 cells with toll like receptor 4 (TLR4) inhibitor resatorvid (TAK-242) or TLR4 silence RNA (siRNA) blocked CYP3A4 and P-gp down-regulation induced by bacterial OMVs. Taken together, we proved in this study that gut microbiota can down-regulate intestinal CYP3A and P-gp partially through producing OMVs to activate the TLR4 signaling pathway.
Bupleuri Radix is one of the most frequently used herbal medicines in China with a 2000-year medicinal history. However, the use of Bupleuri Radix is very confused. Twenty-five species and eight varieties of Bupleurum have been used as Bupleuri Radix in different regions of China. It is very difficult to identify these Bupleurum species using traditional morphological method. In order to establish a fast and effective method to identify these Bupleurum species, we collected 168 Bupleurum medicinal plants from 14 populations of 9 provinces, and amplified their ITS sequences. 168 ITS sequences with a full length of 600-606 bp were obtained. DNAMAN analyzing results showed that 86 variable sites were present in these sequences and 19 haplotypes (TH1-TH19) were determined. After calculating K2P distance and analyzing an NJ tree, we established a molecular identification method based on ITS sequence. Using this method,52 samples of Bupleuri Radix were identified successfully. Furthermore, we tested saikosaponin a, c, d contents in these Bupleuri Radix by HPLC and analyzed the results by ANOVA and LSD T test to evaluate the quality of Bupleuri Radix. This method is significant for effective identification of Bupleurum medicinal plants, and quality control of Bupleuri Radix in the market.
The major non-P450 enzymes involved in the oxidative metabolism of drugs are:the flavincontaining monooxygenase (FMO), the monoamine oxidase (MAO), the aldehyde oxidase (AO), the xanthine oxidase (XO), the alcohol dehydrogenase (ADH) and the aldehyde dehydrogenase (ALDH). In recent years, the role of non-P450 enzymes in drug oxidative metabolism has garnered increasing attention. However, the contribution of non-P450 enzymes to the drug oxidative metabolism is possibly underestimated in many cases, as most metabolism studies in drug discovery and lead optimization are conducted using in vitro test systems related to P450 enzymes. In this article, these non-P450 enzymes in terms of catalyzed reaction types, common substrates, gene polymorphism and drug interaction are reviewed, and the in vitro models and factors for non-P450-mediated oxidative metabolism are summarized. Similar to P450 enzymes, non-P450 enzymes can directly catalyze the oxidation of drugs, yielding therapeutically active metabolites or toxic metabolites. These enzymes can also oxidize the toxic metabolites, generated from P450-catalyzed reaction, to nontoxic metabolites. In general, most non-P450 enzymes (such as FMO and MAO) appear to be much less inducible than P450 enzymes.
This study was designed to clarify the chemical constituents in Yuanhu Zhitong prescription (YHZT), a rapid high performance liquid chromatography/electrospray ionization quadruple time-of-flight mass spectrometry (HPLC-QTOF/MS) method was established. Based on the high resolution MS spectra data, fragmentation ion information, reference standards data and literature reports, 51 peaks including 28 alkaloid compounds and 23 coumarin compounds were identified. The chemical constituents in YHZT were rapidly, accurately, systematically analyzed. The results lay a foundation for the quality control of effective compounds of YHZT.
Pharmacogenomics is defined as research into the relationship between inherited genetic variations in drug metabolizing enzymes, transporters and targets and individual variations in person's response to drugs (fate of drug in human body, safety and efficacy). Personalized dosing is pharmacogenomics-based therapeutic regimen tailored to other individual characteristics. This article summarizes the progress in clinical application of personalized dosing from the perspective of pharmacogenomics of drug metabolizing enzymes and transporters, and proposes to draw attention to key scientific issues (e.g., the effect of multi-genes and non-genetic factors on drug effects, the integration of therapeutic drug monitoring and pharmacogenomics); meanwhile, bottle necks in the clinical application and corresponding strategies are proposed.
Polyamidoamine (PAMAM) dendrimers as synthetic gene vectors are efficient gene delivery systems. In this study, a kind of α-cyclodextrin-PAMAM conjugates polymer (CyD-G1) was synthesized as a gene delivery vector. Based on 1H NMR detectation, about 6.4 PAMAM-G1 molecules was grafted onto an α-CD core. Agarose gel electrophoresis revealed that CyD-G1 could efficiently bind with DNA to condense them into nano-scale particles, which showed a similar binding capacity of PEI-25K. Besides, it could protect DNA from DNase I degradation in a low N/P ratio. When N/P ratio in the CyD-G1/DNA polyplex was 40, the average particle size of CyD-G1/DNA polyplex was about 120 nm, and zeta potential was +21 mV. This polyplex could maintain its particle size in serum-containing solution within 360 min. In comparison with PEI-25K carrier, CyD-G1 showed low cytotoxicity in various cell lines. Cell transfection results showed that CyD-G1 efficiently delivered DNA into cells at N/P=80 compared with Lipofectamine 2000 and PEI-25K.Unlike Lipofectamine 2000 and PEI-25K, in serum-containing test condition, CyD-G1/DNA polyplex could maintain the transgene activities. The results of confocal laser scanning microscopy indicated that most DNA entered into cell nuclei within 4 h, and this phenomenon was consistent with the results calculated by flow cytometry. Taken together, CyD-G1 showed good transgene activities and the gene delivery vector could be used not only in vitro but also in vivo.
Tropane alkaloids are anticholinergic drugs widely used clinically. Biosynthesis of tropane alkaloids in planta involves a step of transamination of phenylalanine. Based on the sequenced transcriptomes of lateral roots and leaves of Hyoscyamus niger, we found three annotated aromatic amino acid aminotransferases, which were respectively named HnArAT1, HnArAT2 and HnArAT3. Sequence analysis showed that HnArAT3 had highest similarity with the reported Atropa belladonna AbArAT4, which was involved in tropane alkaloid (TA) to provide the precursor of the phenyllactic acid moiety. Tissue expression pattern analysis indicated that HnArAT3 was specifically expressed in lateral roots, where is the organ synthesizing tropane alkaloids. Then, method of virus induced gene silencing (VIGS) was used to characterize the function of HnArAT3 in H. niger. Gene expression analysis given by real-time quantitative PCR showed that all the transgenic lines had lower expression levels of HnArAT3 than the non-transgenic control, and HPLC analysis of alkaloids demonstrated significant decrease in the contents of hyoscyamine, anisodamine and scopolamine in planta. These results suggested that HnArAT3 was involved in the phenyllactic acid branch of TA biosynthetic pathway. Molecular cloning and functional identification of HnArAT3 laid the foundation for further understanding of TA biosynthesis and metabolic regulation, and also provided a new candidate gene for engineering biosynthetic pathway of tropane alkaloids.
This study was designed to screen the targets of bioactive ingredients of Baihe Dihuang Tang, and investigate the "multi-components, multi-targets and multi-pathways" intervention mechanism of Baihe Dihuang Tang on psychological sub-health. The ADME/T calculation method was used to screen the active ingredient of Baihe Dihuang Tang, and then using ADME/T calculation method to filtrate the active components of Baihe Dihuang Tang, then Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP), PharmMapper database and Medical Subject Headings (MeSH) were combined to forecast and filtrate the targets of the main active ingredients. In addition, the predicted targets were verified by the Surflex-dock in Sybyl. The Cytoscape software was used to construct the Baihe Dihuang Tang ingredients-targets-disease network, while ClueGO software was used to analyze the molecular function and biological process of the targets. There are total 11 active ingredients and 21 targets in Baihe Dihuang Tang. A good interaction between them was supported by the score. The 21 targets were mainly involved in gamma-aminobutyric acid signaling pathway, cAMP metabolic process and monoamine transport relevant biological processes. Thus, Baihe Dihuang Tang may play a role in the intervention of psychological sub-health by regulating the activity of G-protein coupled amine receptor and the expression of monoamine neurotransmitter, which reflects the features of traditional Chinese medicine multi-components, multi-targets and multi-pathways. This research provides evidences on the pharmacological mechanism of Baihe Dihuang Tang effect on psychological sub-health.