Effects of chronic hepatitis B virus infection on human hepatic cytochrome P450 2C9 / 中华传染病杂志

Objective To investigate the effects of chronic hepatitis B virus (HBV) infection on human hepatic cytochrome P450 2C9 (CYP2C9).Methods Liver tissue samples and blood samples were obtained from 10 patients with chronic HBV infeetion and 10 healthy controls.CYP2C9 genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.The activity of CYP2C9 was detected utilizing high performance liquid chromatography (HPLC).The expressions of CYP2C9 mRNA and protein were determined by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western-blotting.The data were analyzed by t test.Results All the liver samples showed CYP2C9 wild-type (*1*1),while CYP2C9 (*2) and CYP2C9 (*3) were not detected.The maximum velocity (Vmax) of CYP2C9 in patients chronic HBV infection and healthy controls were (263.5±66.4) μmol/L and(284.6±85.9) μmol/L,respectively (t=0.614,P=0.5471).The expression of CYP2C9 mRNA in patients with chronic HBV infection (0.39±0.28) was significantly lower than that of healthy controls (0.65±0.13) (t=2.628,P=0.0171).Accordingly,the protein expression in patients with chronic HBV infection (0.26±0.13) was lower than that of healthy controls (0.60±0.19) (t=4.688,P=0.000 2).Conclusion The expressions of CYP2C9 mRNA and protein are decreased in chronic HBV infection which may down-regulate the enzyme activity.

The structure-function relationship analysis of VEGI: Y111 is an important residue in biological activity / 中国药理学通报

Aim Vascular endothelial cell growth inhibitor(VEGI) is a recently discovered novel member of the TNF superfamily,which is expressed predominantly in endothelial cells.As an endothelial cell-specific negative regulator of angiogenesis,the relationship between structure and function of VEGI is not understood at present.Methods In order to explore the functional key amino acids of VEGI,four mutants of VEGI(E45→R,G47→A,Y111→F,Y111→T) were construced by site-directed mutagenesis,and recombinant proteins were generated from E.coli.Four mutant proteins behaved similar to the wild type VEGI in various physico-chemical assays.The proliferation of HUVEC and chick choriallantic membrane assay were performed to study the activity of four mutants.Results The mutant E45→R significantly decreased the biological activity,and the mutant G47→A caused a slight drop on activity,but the mutants Y111→F,Y111→T almost completely abolished biological activity.Conclusion It suggests that Y111 is an important residue in biological activity,which may play a direct role in receptor recognition.Moreover,the tyrosine ring and hydroxy group of the amino acid are important determinant of biological activity.Additionally,E45 also plays an important role in biological activity of VEGI.