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Li X.,Huazhong Agricultural University | Jin X.,Hubei Provincial Institute of Veterinary Drug Control | Zhou X.,Huazhong Agricultural University | Wang X.,Huazhong Agricultural University | And 3 more authors.
Biochemical and Biophysical Research Communications | Year: 2014

Pregnane X receptor (PXR) has been identified as a central mediator for coordinate responses to xenobiotic and drug metabolism, and is the major transcriptional regulator of cytochrome P-450 (CYP). Interferon (IFN)-α is known to induce antiviral mechanisms and exert immune regulatory capacity in various cell types. Here, we used primary porcine hepatocytes and a cultured hepatocyte cell line to identify the metabolic role of PXR in IFN-α-mediated CYP3A29 expression. We found that IFN-α could activate PXR in both time- and dose-dependent manners in pigs. Activation of PXR significantly increased CYP3A29 mRNA and protein expression. Meanwhile, the expression of CYP3A29 induced by IFN-α occurred after the increase of PXR expression in porcine hepatocytes. In addition, the IFN-α-induced CYP3A29 expression was blocked by PXR knockdown. The PXR-overexpressed cells (transfected with porcine PXR) increased CYP3A29 mRNA and protein expression. Furthermore, in animal experiments, we found that IFN-α increased both CYP3A29 mRNA and protein levels. Collectively, our results suggest that PXR plays an important role in IFN-α-mediated CYP3A29 expression in porcine hepatocytes. © 2014 Elsevier Inc. All rights reserved. Source


Li X.,Huazhong Agricultural University | Hu X.,Wuhan Institute of Animal Husbandry and Veterinary Science | Jin X.,Hubei Provincial Institute of Veterinary Drug Control | Zhou X.,Huazhong Agricultural University | And 3 more authors.
Xenobiotica | Year: 2015

1. The expression and the activity of cytochromes P450 (CYPs) can be elevated by the activation of nuclear receptors. The pregnane X receptor (PXR, or nuclear receptor NR1I2) is a ligand-activated transcription factor that mediates responses to diverse xenobiotics and endogenous chemicals. Here we investigated the regulatory role of PXR in IFN-γ-mediated CYP3A29 expression in pig liver microsomes, primary porcine hepatocytes, and a cultured hepatocyte cell line. 2. IFN-γ significantly up-regulated CYP3A29 and PXR expressions at mRNA and protein levels in a dose-dependent manner. IFN-γ treatment significantly increased the metabolism of nifedipine. PXR and IFN-γ treatments significantly enhanced the activity of CYP3A29 promoter and the upstream region from -1473 to -1021 of CYP3A29 might be PXR-binding site. Moreover, the IFN-γ-induced CYP3A29 expression was blocked by PXR knockdown, whereas CYP3A29 mRNA and protein expression levels were dramatically elevated by PXR overexpression. 3. The regulatory effect of IFN-γ on CYP3A29 expression is mediated via PXR. © 2014 Informa UK Ltd. All rights reserved: reproduction in whole or part not permitted. Source


Guo Y.,Huazhong Agricultural University | Ngom B.,Huazhong Agricultural University | Le T.,Huazhong Agricultural University | Le T.,Xinyang Agricultural College | And 5 more authors.
Analytical Chemistry | Year: 2010

A rapid and sensitive immunochromatographic assay (ICA) based on competitive format was developed and validated for simultaneous detection of sulfamethazine (SM2), sulfadiazine (SDZ), and sulfaquinoxaline (SQX) in chicken breast muscle and egg samples. For this purpose, three monoclonal antibodies raised against those three sulfonamides were conjugated to colloidal gold particles and applied to the conjugate pads of the test strip. The competitors of the sulfonamides (SM2/SDZ/SQX-bovine serum albumin conjugates) were immobilized onto a nitrocellulose membrane at three detection zones to form T1, T2, and T3, respectively. With this method, the cutoff values for the three test lines were achieved at 80 μg/kg, which is lower than the maximum residue levels (MRLs) established for sulfonamides. The recoveries in negative samples spiked at concentrations of 10, 50, and 100 μg/kg ranged from 75% to 82% for egg samples and from 78% to 81% for chicken samples. The method was compared with the HPLC method by testing 180 eggs and chicken breast samples from local markets, and an agreement rate of 99.7% was obtained between the two methods. © 2010 American Chemical Society. Source


Ngom B.,Huazhong Agricultural University | Guo Y.,Huazhong Agricultural University | Jin X.,Hubei Provincial Institute of Veterinary Drug Control | Shi D.,Huazhong Agricultural University | And 6 more authors.
Food and Agricultural Immunology | Year: 2011

A lateral flow immunoassay (LFIA) and a competitive indirect ELISA (ciELISA) were developed and validated for the quantitative analysis of sulfaquinoxaline (SQX) in chicken tissues. The limits of quantification of ciELISA were 5 ng/ml for muscle samples and 12.5 ng/ml for liver samples; recoveries in tissues spiked with SQX at 25, 40 and 50 ng/g were 73.4-87.4% (n=5). With LFIA, no matrix effect was noticed during sample analyses. The optimisation of components allowed a detection limit of 0.5 ng/ml in tissues, which was 10-25 times lower than ciELISA. The recoveries in tissues fortified at levels 5, 10, 25 and 50 ng/g were 75.8-98% (n=5). Using HPLC as confirmatory method, 70 chicken muscle and liver samples from animal experiments were analysed by two immunoassays. The assay time for LFIA was only five min, whereas the analyses by ciELISA and HPLC took several hours. Comparison of ELISA, LFIA and HPLC data showed good correlations (r2=0.99). © 2011 Taylor & Francis. Source

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