OBJECTIVETo generate recombinant human tissue factor pathway inhibitor (TFPI) in Pichia pastoris.

METHODSTo improve the expression of TFPI, a silent mutation was generated at the specific site of TFPI cDNA. Both wild-type TFPI cDNA and mutated TFPI cDNA were cloned into the expression vector pPic9. The constructed plasmids were subsequently transformed into Pichia pastoris cells GS115 and KM71, and the transformants were confirmed by polymerase chain reaction and DNA sequencing. The expression of recombinant protein was induced by addition of 0.5% methanol in the culture medium. The cell culture medium after induction was concentrated through ultra filtration. The recombinant protein was further purified by a three-step process (Heparin-sepharose CL-6B affinity chromatography, DEAE-Sepharose Fast Flow affinity chromatography, and Sephadex G75-gel filtration). The amount of the recombinant protein was quantified with gel imaging system. The activity of the recombinant protein was analyzed by the chromogenic substrate assay.

RESULTSThe amount of TFPI expressed in the mutated clone (1 mg/L) was much higher than that in the wild type clone (0.1 mg/L). The TFPI activity in the recombinant GS115 cells could be detected 12 hours after induction and reached the peak at 36 hours, while the TFPI activity in the recombinant KM71 cells started to show up at 24 hours after induction and reached the peak at 72 hours. The expression of recombinant protein in the silent mutant was significantly higher than those of wild type clone in both GS115 and KM71 host cells. The relative molecular mass of recombinant TFPI was approximately 42 000.

CONCLUSIONIntroduction of the silent mutation at the specific site of TFPI cDNA can increase the recombinant protein expression in Pichia pastoris, which is much higher than that in insect cells or saccharomyces cerevisiae.

Humans ; Lipoproteins ; biosynthesis ; genetics ; Mutation ; Pichia ; genetics ; metabolism ; Recombinant Proteins ; biosynthesis ; genetics

Animals ; Atherosclerosis ; etiology ; metabolism ; Gene Expression Regulation ; Humans ; Lipase ; analysis ; genetics ; physiology ; Lipoproteins ; metabolism ; Lipoproteins, HDL ; metabolism ; Lipoproteins, LDL ; metabolism ; Polymorphism, Genetic ; Tissue Distribution

Apoptosis ; Human Umbilical Vein Endothelial Cells ; Humans ; Lipoproteins, LDL/adverse effects* ; MicroRNAs/genetics* ; Molecular Chaperones/genetics*

Tissue factor pathway inhibitor (TFPI) is one of the major physiological inhibitors of the human blood coagulation cascade and may have great potential in the prevention and therapy of diseases caused by thrombus formation. In this study, recombinant human tissue factor was generated in E. coli containing a recombinant vector constructed by inserting TFPI cDNA into pGEX-2T vector. The generated recombinant TFPI (rTFPI) could be simply purified with glutathione-agarose affinity method and maintained its biological function in terms of inhibition of tissue factor and factor Xa.
Escherichia coli ; genetics ; metabolism ; Humans ; Lipoproteins ; biosynthesis ; genetics ; pharmacology ; Peptide Fragments ; biosynthesis ; genetics ; pharmacology ; Plasmids ; Recombinant Proteins ; biosynthesis ; pharmacology ; Transfection

OBJECTIVETo express the recombinant D protein in prokaryotic expression system solubly and make preparation for producing D-carrier conjugate vaccine next step.

METHODSThe hpd gene fragment removed of signal peptide from genomic DNA of Hib CMCC was inserted into pET43. 1a. The recombinant plasmid was transformed to competent E. coli BL21 (DE3) for expression under induction of IPTG. The expressed recombination protein was precipitated with ammonium sulfate, purified by DEAE anion exchange column chromatography and identified for reactogenicity by Western Blot.

RESULTSThe expressed recombination protein, in a soluble form, constained about 50% of total somatic protein and showed specific reaction with the HIB antisera after preliminary purification.

CONCLUSIONThe D protein recombined expression plasmid was constructed successfully and expressed D protein in prokaryotic cells in a solube form.

Bacterial Proteins ; genetics ; Blotting, Western ; Carrier Proteins ; genetics ; Escherichia coli ; genetics ; Haemophilus influenzae type b ; genetics ; Immunoglobulin D ; genetics ; Lipoproteins ; genetics ; Plasmids ; Recombinant Proteins ; biosynthesis ; Solubility

OBJECTIVETo explore low density lipoprotein (LDL) oxidation by macrophage myeloperoxidase (MPO) at molecular level.

METHODSUsing a mouse macrophage model, we examined the relationship between LDL oxidation and macrophage MPO by measuring macrophage MPO activity, LDL oxidation products, MPO gene expression and cellular orientation of LDL oxidation.

RESULTSMPO gene expression increased to its maximum gradually when the concentration of LDL was increased, and then maintained at that level. NaN(3) inhibied the elevation of MPO activity and LDL oxidation, which was LDL concentration-dependent. After the composition of macrophage membrane was roughly analyzed, it was determined that the contents of MPO and LDL in 5% sucrose were 7.667 and 21 times higher than those in 10% sucrose, respectively.

CONCLUSIONLDL is attached to the "microdomain" of the macrophage membrane in which LDL is oxidized by MPO.

Animals ; Lipoproteins, LDL ; metabolism ; Macrophages ; metabolism ; Mice ; Oxidation-Reduction ; Peroxidase ; genetics ; metabolism

OBJECTIVETo determine expression changes of major outer membrane protein(OMP) antigens of Leptospira interrogans serogroup Icterohaemorrhagiae serovar Lai strain Lai during infection of human macrophages and its mechanism.

METHODSOmpR encoding genes and OmpR-related histidine kinase (HK) encoding gene of L.interrogans strain Lai and their functional domains were predicted using bioinformatics technique. mRNA level changes of the leptospiral major OMP-encoding genes before and after infection of human THP-1 macrophages were detected by real-time fluorescence quantitative RT-PCR. Effects of the OmpR-encoding genes and HK-encoding gene on the expression of leptospiral OMPs during infection were determined by HK-peptide antiserum block assay and closantel inhibitive assays.

RESULTSThe bioinformatics analysis indicated that LB015 and LB333 were referred to OmpR-encoding genes of the spirochete, while LB014 might act as a OmpR-related HK-encoding gene. After the spirochete infecting THP-1 cells, mRNA levels of leptospiral lipL21, lipL32 and lipL41 genes were rapidly and persistently down-regulated (P <0.01), whereas mRNA levels of leptospiral groEL, mce, loa22 and ligB genes were rapidly but transiently up-regulated (P<0.01). The treatment with closantel and HK-peptide antiserum partly reversed the infection-based down-regulated mRNA levels of lipL21 and lipL48 genes (P <0.01). Moreover, closantel caused a decrease of the infection-based up-regulated mRNA levels of groEL, mce, loa22 and ligB genes (P <0.01).

CONCLUSIONExpression levels of L.interrogans strain Lai major OMP antigens present notable changes during infection of human macrophages. There is a group of OmpR-and HK-encoding genes which may play a major role in down-regulation of expression levels of partial OMP antigens during infection.

Antigens, Bacterial ; genetics ; metabolism ; Bacterial Outer Membrane Proteins ; genetics ; metabolism ; Cell Line ; Chaperonin 60 ; genetics ; metabolism ; Humans ; Leptospira interrogans ; genetics ; immunology ; pathogenicity ; Lipoproteins ; genetics ; metabolism ; Macrophages ; microbiology

OBJECTIVETo analyze factors related to the virulence associated genes of Leptospires.

METHODSTwelve putative virulence associated genes were detected by polymerase chain reaction (PCR) method in 38 reference strains, 81 field strains of Leptospira interrogans isolated from patients or animals, and 12 avirulent strains of Leptospira biflexa.

RESULTSThese putative virulent genes were widely distributed among the strains of Leptospira interrogans, but only few of them were detected in Leptospira biflexa. Gene lipL32 was detected in all strains of Leptospira interrogans. Distribution of gene lipL36 was varied significantly with detected rates from 0 to 90.91%. Gene la1608 had a positive rate of 87.50% for strains of serogroup Icterohaemorrhagiae, but was only detected in few strains of other serogroups with a range from 0 to 25.00%. Rate of detection on gene sphA was 17.65% in Leptospira interrogans, and was absent in serovar hardjo reference strain.

CONCLUSIONResults indicated that these genes might be of importance for the virulence and pathogenicity of Leptospira interrogans, while gene lipL32 might be one of the common antigens. Gene lipL36 might be involved in serogroup specificity with genetic diversity, but gene la1608 was as one of the genes with specificity for serogroup Icterohaemorrhagiae. However, serovar hadjo might hold quite different genetic characteristics when compared with the other serovars of Leptospires.

Bacterial Outer Membrane Proteins ; genetics ; Bacterial Proteins ; genetics ; Carbohydrate Dehydrogenases ; genetics ; Flagellin ; genetics ; Genes, Bacterial ; genetics ; Hemolysin Proteins ; genetics ; Leptospira ; genetics ; pathogenicity ; Lipoproteins ; genetics ; Polymerase Chain Reaction ; Virulence ; genetics ; Virulence Factors ; genetics

The preparation and cell transfection of chitosan-DNA nanoparticles were studied. The TFPI (tissue factor pathway inhibitor) or EGFP (enhanced green fluorescent protein) plasmid DNA was encapsulated with chitosan to form gene nanoparticles. The results with TEM showed that the nanoparticles were of sphere shape. The mean diameter of the nanoparticles was 149 nm and the diameter ranged from 80-250 nm, which were measured by the photo related spectrometry (PCS). The encapsulation efficiency of DNA was 96% +/- 1.38% and the DNA content in the nanoparticles was 37% +/- 3.0%. The encapsulated DNA could be protected from the degradation by DNase I. The transfection efficiency of chitosan nanoparticles were about equivalent to that of the LipofectAMINETM reagent. Our results also showed that chitosan nanoparticles were nontoxic to cultured cells.
Cells, Cultured ; Chitosan ; chemistry ; DNA ; chemistry ; genetics ; Genetic Vectors ; Green Fluorescent Proteins ; genetics ; Humans ; Lipoproteins ; genetics ; Muscle, Smooth, Vascular ; chemistry ; metabolism ; Nanoparticles ; chemistry ; Plasmids ; genetics ; Transfection

OBJECTIVE: To investigate the effect of miR-590-5p on the expression of lectin-like oxidized low density lipoprotein receptor 1 (LOX-1) in apoptotic human umbilical vein endothelial cells (HUVECs) induced by ox-LDL, and to explore the role of miR-590-5p in modulating HUVECs apoptosis. METHODS: HUVECs were exposed to ox-LDL (50 μg/mL) for 0 to 48 h. Apoptosis was detected by Annexin V-FITC stain and was distinguished from necrosis by propidium iodide (PI) staining. The relative expression level of miR-590-5p in HUVECs was analyzed using real-time quantitative PCR (RT-qPCR). HUVECs were transfected with miR-590-5p mimics or miRNA mimics control followed by 50 μg/mL ox-LDL stimulation for 48 h. LOX-1 mRNA and protein were measured by RT-qPCR and Western blot, and apoptosis in HUVECs was analyzed by flow ctyometry after Annexin V-FITC/PI double stain. RESULTS: Incubation of HUVECs with 50 μg/mL ox-LDL for 0 to 48 h resulted in a time-dependent induction of apoptotic cell death and down-regulation of miR-590-5p. Transfection of miR-590-5p mimics suppressed LOX-1 expression at both mRNA and protein levels, leading to a reduction of ox-LDL-induced apoptosis in HUVECs. CONCLUSION MiR-590-5p protects endothelial cells from ox-LDL induced apoptosis by inhibiting the expression of LOX-1.
Apoptosis ; genetics ; Cells, Cultured ; Human Umbilical Vein Endothelial Cells ; cytology ; Humans ; Lipoproteins, LDL ; pharmacology ; MicroRNAs ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Scavenger Receptors, Class E ; genetics ; metabolism ; Transfection