NF-κB site of promotor mediates nicotine-induced ICAM-1 expression in human umbilical vein endothelial cells

AIM:To study the mechanisms of nicotine-induced expression of intercellular adhesion molecule-1(ICAM-1).METHODS:Related luciferase reporter gene plasmids were constructed with molecular cloning techniques;above plasmids and intracontrol plasmid pSV-β-gal were co-transfected into human umbilical vein endothelial cells(HUVECs) with eukaryotic gene transfection techniques; the relative luciferase activities were detected in the transfected HUVECs.RESULTS:Series of luciferase reporter gene containing different sequences of human ICAM-1 promotor and site-directed mutants of NF-κB and Sp-1 in promotor were successfully constructed; Nicotine could increase the expression of luciferase reporter gene plasmid containing-579 bp(pGL3E-579/+36),-230 bp(pGL3E-230/+36) and mutated Sp-1 version(pGL3E-Sp-1-MU)(P＜0.05 vs control) of ICAM-1 promotor in the transfected HUVECs, whereas deletion derivative (pGL3E-134/+36) and mutation (pGL3E- NF-κB -MU) of downstream NF-κB site of ICAM-1 promotor prevent nicotine-induced increase in expression of luciferase reporter gene plasmid.CONCLUSION:NF-κB site of promotor mediates nicotine-induced ICAM-1 expression in human umbilical vein endothelial cells.     

Cholesterol-sensitive action sites in promoter of prohibitin gene

AIM: To verify the cholesterol-sensitive sites in the promoter of prohibitin (PHB) gene. METHODS: A series of successive PHB promoter truncated segments were amplified by PCR and cloned into pGL3-Basic luciferase reporter vector. Human prostate cancer PC-3 cells were transfected with the recombinant plasmids and then cultured in normal medium (NM) or cholesterol-depleted medium (CDM). The activity of PHB promoter was detected by luciferase activity analysis to find the cholesterol-sensitive region of approximately 200 bp in PHB promoter. Point mutations in sterol regulatory element (SRE) homologous loci of this 200　bp region were made to confirm the cholesterol-sensitive role of this SRE site. RESULTS: Plasmids with PHB promoter segments were successfully constructed. Luciferase activity in PC-3 cells transfected with PHB promoter segment pPHB-179 (-35/+138) plasmid was significantly decreased compared with the cells transfected with the whole PHB promoter pPHB-1192 plasmid (P<0.05). After point mutation was made in the SRE homologous locus located at -117 to -108 bp and this plasmid was transfected into PC-3 cells, the luciferase activity in these cells was significant decreased compared with the cells transfected with pPHB-1192 plasmid (P<0.05). CONCLUSION: Cholesterol regulates the activity of PHB promoter in human prostate cancer PC-3 cells. The cholesterol-sensitive site in PHB promoter is located at -117 to -108 bp of SRE homologous locus. PHB may become a new target of gene therapy for prostate cancer.     

Effect of NPPB and niflumic acid on expression of GCL and CLIC4 in H2O2 injured C6 glioma cells

AIM: To observe the effect of 5-nitro-2- (3-phenylpropylamino) benzoate acid (NPPB), niflumic acid (NFA) (chloride channel blockers) on malignant glioma C6 cells injured by hydrogen peroxide (H₂O₂). METHODS: The viability of C6 cells treated with NPPB, NFA and H₂O₂ was measured by MTT assay. LDH release rate and GSH contents were detected by ultraviolet spectrophotometry. mRNA levels of GCLC, GCLM and CLIC4 were determined by RT-PCR. CLIC4 protein level was detected by Western blotting. RESULTS: Compared to the control group, H₂O₂ treatment induced the decrease in cell viability and GSH contents, the increase in LDH release rate, the decrease in the expression of GCLC, GCLM and CLIC4 mRNA and the increase in CLIC4 protein level (P<0.05 ), respectively. Compared with the H₂O₂ group, H₂O₂ combined with NPPB or NFA treatment did not change the cell viability, the GSH contents and the GCLC, GCLM mRNA expression. However, the LDH release rate and CLIC4 protein level decreased (P<0.05). CONCLUSION: The chloride channel blockers NPPB or NFA lessen the oxidative injury of C6 cells through modulating the function of membrane and down-regulating the protein expression of CLIC4.     

Relationship between blood pressure and fibrinogenic expression of fibrinogen Bβ-chain gene polymorphisms

AIM: To study the correlation between blood pressure and 6 common fibrinogen (Fg) Bβ-chain gene polymorphisms (Bβ-854G/A,-455G/A,-249C/T,-148C/T, 448G/A, Bcl-1G/A), and to investigate the effect of blood pressure on plasma fibrinogen concentration and the functional expression of fibrinogen. METHODS: 1 391 subjects from Kailuan Group Corporation were enrolled for medical examination and questionnaire survey. Venous blood were collected in the early morning to measure Fg concentration, fibrin monomer polymerized velocity (FMPV), absorbance maximum (A_max) and FMPV/A_max. The blood pressure was also measured and the subjects were accordingly divided into hypertension group (HG) and the normal blood pressure group (NG). The 6 gene polymorphisms were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: No differences of the genotype frequencies of the 6 sites between hypertension group (HG) and normal blood pressure group (NG) were found (P>0.05). No differences of Fg concentration and FMPV/A_max between HG group and NG group were observed (P>0.05). However, FMPV and A_max in HG group were lower than those in NG group (P<0.05). In HG and NG group, the Fg concentration, FMPV, A_max, FMPV/A_max in the subjects with Bβ-854 mutated genotype were all higher than those in the subjects with wild genotype (P<0.05). In NG group, the Fg concentration and FMPV in the subjects with Bβ Bcl-1 mutated genotype were higher than those in the subjects with wild genotype (P<0.05). Fg, FMPV and A_max in the subjects with Bβ-854 and Bcl-1 mutated genotype in HG group were lower than those in NG group (P<0.05). CONCLUSION: Fg Bβ-854 is one of the main gene situs of regulating the functional expression of fibrinogen. Bcl-1 mutated genotype increases plasma Fg concentration and FMPV. Hypertension decreases the effect of this regulation, and affects the process of fibrin monomer aggregation into dimer, resulting in a special type of coagulation dysfunction.