Construction of a targeting adenoviral vector carrying AFP promoter for expressing EGFP gene in AFP-producing hepatocarcinoma cell

AIM:To construct a recombinant adenoviral vector carrying AFP promoter and EGFP gene for specific expression of EGFP gene in AFP producing hepatocellular carcinoma (HCC) HepG2 cells.METHODS: Based on the Adeno-X^TM expression system, the human immediate early cytomegalovirus promoter (PCMV IE)was removed from the plasmid, pshuttle,and replaced by a 0.3 kb (α-fetoprotein (AFP) promoter that was synthesized by polymerase chain reaction (PCR).The enhanced green fluorescent protein (EGFP) gene was inserted into the multiclone site (MCS),and then the recombinant adenovirus vector carrying the 0.3kb AFP promoter and EGFP gene was constructed.Cells of a normal liver cell line (LO2),a hepatocarcinoma cell line (HepG2) and a cervical cancer cell line (HeLa) were transfected with the adenovirus.Northern blot and fluorescence microscopy were used to detect the expression of the EGFP gene at mRNA or protein level in three different cell lines.RESULTS:The 0.3kb AFP promoter was synthesized through PCR from the human genome.The AFP promoter and EGFP gene were directly inserted into the plasmid pshuttle as confirmed by restriction digestion and DNA sequencing.Northern blot showed that EGFP gene was markedly transcribed in HepG2 cells,but only slightly in LO2 and HeLa cells.In addition,strong green fluorescence was observed in HepG2 cells under a fluorescence microscopy,but fluorescence was very weak in LO2 and HeLa cells.CONCLUSION:Under control of the 0.3kb human AFP promoter, the recombinant adenovirus vector carrying EGFP gene can be specially expressed in AFP-producing HepG2 cells,Therefore,this adenovirus system can be used as a novel,potent and specific tool for gene-targeting therapy for the AFP positive primary hepatocellular carcinoma,

Synthesis of endotoxin receptor CD14 protein in Kupffer cells and its role in alcohol-induced liver disease

AIM: To observe the synthesis of endotoxin receptor CD14 protein and its mRNA expression in Kupffer cells (KCs), and evaluate the role of CD14 in the pathogenesis of liver injury in rats with alcohol-induced liver disease (ALD).METHODS: Twenty-eight Wistar rats were divided into two groups: ethanol-fed group and control group. Ethanol-fed group dextrose instead of ethanol. Two groups were sacrificed at 4 wk and 8 wk, respectively. KCs were isolated and the synthesis of CD14 protein and its mRNA expression in KCs were determined by flow cytometric analysis (FCM)or the reverse transcription polymerase chain reaction (RTPCR) analysis. The levels of plasma endotoxin and alanine transaminase (ALT) were measured by Limulus Amebocyte Lysate assay and standard enzymatic procedures respectively, and the levels of plasma tumor necosis factor (TNF)-α and interleukin (IL)-6 were both determined by ELISA. The liver pathology change was observed under light and electric microscopy.RESULTS: In ethanol-fed group, the percentages of FITCCD14 positive cells were 76.23 % and 89.42 % at 4 wk and 8 wk, respectively. Compared with control group (4.45 %and 5.38 %), the difference was significant (P＜0.05). The expressions of CD14 mRNA were 7.56±1.02 and 8.74±1.37 at 4 wk and 8 wk, respectively, which were significantly higher compared with the control group (1.77±0.21 and 1.98±0.23)(P＜0.05). Plasma endotoxin levels at 4 wk and 8 wk increased dramatically in ethanol-fed rats (112±15 IU/L and 147±22 IU/L) than those in the control animals (31±12 IU/L and 33±9 IU/L) (P＜0.05). In ethanol-fed rats, the levels of wk, respectively which were significantly higher than those fed rats, there were marked pathological changes including steatosis, cell infiltration and necrosis. No marked pathological changes were seen in control group.CONCLUSION: Ethanol administration led to a significantsynthesis of endotoxin receptor CD14 protein and its gene expression in KCs, which maybe result in the pathological changes of liver tissue and hepatic functional damages.

Effects of tumor necrosis factor,endothelin and nitric oxide on hyperdynamic circulation of rats with acute and chronic portal hypertension

AIM:To evaluate the effect of tumor necrosis factor (TNF),endothelin (ET) and nitric oxide (NO) on hyperdynamic circulation (HC) of rats with acute and chronic portal hypertension (PHT).METHODS: Chronic portal hypertension was induced in Wistar rats by injection of carbon tetrachloride. After two weeks of cirrhosis formation, L-NMMA (25mg/kg) was injected into one group of cirrhotic rats via femoral vein and the experiment was begun immediately. Another group of cirrhotic rats was injected with anti-rat TNFα (300mg/kg) via abdominal cavity twice within 48h and the experiment was performed 24h after the second injection. The blood concentrations of TNFα, ET-1 and NO in portal vein and the nitric oxide synthase (NOS) activity in hepatic tissue were determined pre-and post-injection of anti-rat TNFα or LNMMA. Stroke volume (SV), cardiac output (CO), portal pressure (PP), superior mesenteric artery blood flow (SMA flow) and lilac artery blood flow (IAflow) were measured simultaneously. Acute portal hypertension was established in Wistar rats by partial portal-vein ligation (PVL). The parameters mentioned above were determined at 0.5h,24h, 48h, 72h and 120h after PVL. After the formation of stable PHT, the PVL rats were injected with anti-rat TNFα or L-NMMA according to different groups, the parameters mentioned above were also determined.RESULTS:In cirrhotic rats, the blood levels of TNFα, NO in portal vein and the liver NOS activity were significantly increased (P<0.05) while the blood level of ET-1 was not statistically different (P>0.05) from the control animals(477.67±83.81pg/mL vs 48.87±32.79pg/mL, 278.41±20.11μmol/L vs 113.28±14.51μmol/L, 1.81±0.06μ/mg.prot vs 0.87±0.03μ/mg.prot and 14.33±4.42pg/mL vs8.72±0.79pg/mL, respectively). After injection of anti-rat TNFα,the blood level of TNFα was lower than that in controls (15.17±18.79pg/mL vs 48.87±32.79pg/mL). The blood level of NO and the liver NOS activity were significantly decreased, but still higher than those of the controls. The blood level of ET-1 was not significantly changed. PP,SV,CO, SMAflow and IAflow were ameliorated. After injection of L-NMMA, the blood level of NO and the liver NOS activity were recovered to those of the controls. PP and CO were also recovered to those of the controls. SV, SMAflow and IAflow were ameliorated. In PVL rats, the blood levels of TNFα NO in portal vein and the liver NOS activity were gradually increased and reached the highest levels at 48h after PVL. The blood level of ET-1 among different staged animals was not significantly different from the control animals. PP among different staged animals (2.4±0.18kPa at 0.5h, 1.56±0.08kPa at 24h, 1.74±0.1kPa at 48h,2.38±0.05 kPa at 72h, 2.39±0.16 kPa at 120h) was significantly higher than that in controls (0.9±0.16kPa). After injection of anti-rat TNFα in 72h PVL rats, the blood level of TNFα was lower than that in controls (14±14pg/mL vs 48.87±32.79pg/mL). The blood level of NO and the liver NOS activity were significantly decreased, but still higher than those of the controls. The blood level of ET-1 was not significantly changed. PP was decreased from 2.38±0.05kPa to 1.68±0.12kPa, but significantly higher than that in controls. SV, CO, SMAflow and IAflow were ameliorated.After injection of L-NMMA in 72h PVL rats, the blood level of NO and the liver NOS activity were recovered to those of the controls. PP, SV, CO, SMAflow and IAflow were also recovered to those of the controls.CONCLUSION:NO plays a critical role in the development and maintenance of HC in acute PHT and is a key factor for maintenance of HC in chronic PHT. TNFα may not participate in the hemodynamic changes of HC directly, while play an indirect role by inducing the production of NO through activating NOS. No evidence that circulating ET-1 plays a role in both models of portal hypertension has been found.

Role of NF-kB in multiple organ dysfunction during acute obstructive cholangitis

AIM:To elucidate the role of NF-kB activation in the development of multiple organ dysfunction(MOD)during acute obstructive cholangitis(AOC)in rats. METHODS:Forty-two Wistar rats were divided into three groups:the AOC group,the group of bile duct ligation(BDL group),and the sham operation group(SO group).All the animals in the three groups were killed in the 6th and 48th hour after operation.Morphological changes of vital organs were observed under light and electron microscopy.NF-κB activation was determined with Electrophoretic Mobility Shift Assay(EMSA).Arterial blood gas analyses and the serum levels of lactate dehydrogenase(LDH),alanine aminotransferase(ALT),blood urea nitrogen(BUN)and creatinine were performed.The concentrations of TNF-α and IL-6 in plasma were also measured. RESULTS:The significant changes of histology and ultrastructure of vital organs were observed in AOC group. By contrast,in BDL group,all the features of organs damage were greatly reduced.Expression of NF-κB activation in various tissues increased in AOC group when compared to other two groups.At 6 h,the arterial pH in three groups was 7.52±0.01,7.46±0.02,and 7.45±0.02,and the blood pCO_2 was 33.9±0.95 mmHg,38.1±0.89 mmHg,38.9±0.94 mmHg,there was difference in three groups(P<0.05).At 48 h,the blood pH values in three groups was 7.33±0.07, 7.67±0.04,and 7.46±0.03,and blood HCO_3^- was 20.1±1.29 mmol·L^(-1),26.7±1.45 mmol·L^(-1)and 27.4±0.35 mmol·L^(-1),there was also difference in three groups(P<0.05).In AOC group, Levels of LDH,ALT,BUN and creatinine were 16359.9±2278.8 nkat·L^(-1),5796.2±941.9 nkat·L^(-1),55.7±15.3 mg/dl,and 0.72± 0.06 mg/dl,which were higher than in SO group(3739.1± 570.1 nkat·L^(-1),288.4±71.7 nkat·L^(-1),12.5±2.14 mg/dl,and 0.47±0.03 mg/dl)(P<0.05).Levels of plasma TNF-α and IL-6 in AOC at 48 h were 429±56.62 ng·L^(-1)and 562±57 ng·L^(-1), which increased greatly when compared to BDL group (139±16 ng·L^(-1),227±43 ng·L^(-1))and SO group(74±10 ng·L^(-1), 113±19 ng·L^(-1))(P<0.05). CONCLUSION:The pathological damages and the NF-κB activation of many vital organs exised during AOC.These findings have an important implication for the role of NF-κB activation in MOD during AOC.