Screening potential P-glycoprotein inhibitors by combination of a detergent-free membrane protein extraction with surface plasmon resonance biosensor

P-glycoprotein (P-gp) highly expressed in cancer cells can lead to multidrug resistance (MDR) and the combination of anti-cancer drugs with P-gp inhibitor has been a promising strategy to reverse MDR in cancer treatment. In this study, we established a label-free and detergent-free system combining surface plasmon resonance (SPR) biosensor with styrene maleic acid (SMA) polymer membrane proteins (MPs) stabilization technology to screen potential P-gp inhibitors. First, P-gp was extracted from MCF-7/ADR cells using SMA polymer to form SMA liposomes (SMALPs). Following that, SMALPs were immobilized on an SPR biosensor chip to establish a P-gp inhibitor screening system, and the affinity between P-gp and small molecule ligand was determined. The methodological investigation proved that the screening system had good specificity and stability. Nine P-gp ligands were screened out from 50 natural products, and their affinity constants with P-gp were also determined. The in vitro cell verification experiments demonstrated that tetrandrine, fangchinoline, praeruptorin B, neobaicalein, and icariin could significantly increase the sensitivity of MCF-7/ADR cells to Adriamycin (Adr). Moreover, tetrandrine, praeruptorin B, and neobaicalein could reverse MDR in MCF-7/ADR cells by inhibiting the function of P-gp. This is the first time that SMALPs-based stabilization strategy was applied to SPR analysis system. SMA polymer can retain P-gp in the environment of natural lipid bilayer and thus maintain the correct conformation and physiological functions of P-gp. The developed system can quickly and accurately screen small molecule ligands of complex MPs and obtain affinity between complex MPs and small molecule ligands without protein purification.

Clinical analysis of chronic active epstein-barr virus infection in children / 中国综合临床

Objective To study the clinical characteristics of chronic active Epstein-Barr virus (EBV) infection (CAEBV) in children and to provide a basis for the diagnosis and treatment of CAEBV.Methods Clinical data,laboratory serology,pathological examination,treatment and follow-up results of 10 cases with CAEBV infection who were treated in Xijing Hospital of the Fourth Military Medical University from January 2008 to January 2016 were analyzed retrospectively.Results CAEBV major manifestations were continuous or intermittent fever,hepatomegaly,splenomegaly and lymphadenopathy,and others,including general fatigue,cough,hematemesis,diarrhea,skin rash,jaundice,sore throat,muscle joint pain,and so on.And with liver dysfunction,hematologic abnormality,and so on.All patients in anti-EB virus capsid antigen IgG (EBVCA-IgG)antibodies and EBEA-IgG antibodies had positive,while all patients in EBVCA-IgM antibodies had negative.The median load of EBV-DNA detected by real-time polymerase chain reaction(PCR) in the peripheral blood was 7.15× 105 copies/ml.Six of 10 cases CAEBV patients presented a poor clinical course,1 case died from intracranial hemorrhage,2 cases from respiratory failure,1 case from gastrointestinal bleeding,1 case from liver failure,1 case from severe multiple pathogens infection,rest 3 cases showed an improvement and 1 cases had a recurrence.Conclusion CAEBV infection has varieties of clinical features,with poor prognosis and high mortality.If the patients had unexplained fever,hepatomegaly,splenomegaly and lymphadenectasis,we should be timely detect virology and histopathological to diagnosis as early as possible.

Construction of prokaryotic expression vector and expression of human beta defensin 4 gene / 生物医学工程学杂志

Human beta defensin 4 is a small cationic peptide with a broad range of antimicrobial activity. It plays an important role in innate immunity of human body, especially in mucosal and epithelial defense. In this study, the full-length encoding gene of HBD4 was synthesized by overlap extension polymerase chain reaction and inserted into cloning vector pMD18-T. The gene encoding mature peptide of HBD4 was amplified by PCR and cloned into prokaryotic expression vector pGEX-4T-2. Then pGEX-4T-2/mHBD4 was transformed into E. coli DH5 alpha, which was induced by isopropy-beta-D-thiogalactoside (IPTG). The identification was made by means of endonuclease digestion, DNA sequencing, sodium dodecyl sulphate-polyacrylamine gel electrophoresis (SDS-PAGE). The results showed that the synthesized gene and cloned gene were identical to the HBD4 gene sequence registered in GenBank and were successfully cloned into cloning vector pMD18-T and prokaryotic expression vector pGEX-4T-2. After IPTG induction, the GST-HBD4 fusion protein was successfully expressed in E. coli.

THE EXPRESSION OF GLUTAMATE TRANSPORTER IN PLASTIC ASTROCYTES IN FOCAL CEREBRAL INFARCT / 解剖学报

Objective To explore the role of plastic astrocytes in focal cerebral infarct. Methods Immunohistochemical and double immunofluorescence techniques were used in the study. Results The astrcytes positive for glial fibrillary acidic protein(GFAP) occurred in the periinfarct area appeared hypertrophy and proliferation,specially on their processes and formed a network,and the processes oriented toward the infarct center from the periinfarction.The expression of excitatory amino acid transporter 1( EAAT1) increased in the penumbra area of cerebral infarct and manifested spot and fibre.The confocal laser scanning microscopic analysis showed the double staining for EAAT1 and GFAP.Conclusion The plastic astrocytes might participate in the pathological process of cerebral infarct recovery by enhancing the expression of EAAT1.;