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Biomedical subjects

Dong Xi

Publications and source records attributed to Dong Xi.

8 recordsLinked to original sources
PubMed2006

Novel mfgl2 antisense plasmid inhibits murine fgl2 expression and ameliorates murine hepatitis virus type 3-induced fulminant hepatitis in BALB/cJ mice.

Our previous reports, both experimental and human studies, have shown the importance of fibrinogen-like protein-2 (fgl2) prothrombinase in the development of fulminant viral hepatitis, a disease with a mortality of more than 80% in cases lacking immediate organ transplantation. To interfere with this potentially effective target, a 322-bp mouse fgl2 (mfgl2) antisense plasmid complementary to the exon 1 sequence of the gene, including the translation initiation site AUG, was successfully constructed. A dose-dependent inhibitory effect on mfgl2 expression by mfgl2 antisense plasmid was observed in interferon-gamma-treated RAW 264.7 cells. On hydrodynamic delivery, mfgl2 antisense plasmid significantly reduced mfgl2 expression in vivo; markedly ameliorated inflammatory cell infiltration, fibrin deposition, and hepatocyte necrosis; prolonged the survival time period; and elevated the survival rate among BALB/cJ mice with murine hepatitis virus type 3-induced fulminant hepatitis. This study may provide an effective way to interfere with the potential therapeutic target fgl2 gene for fulminant viral hepatitis and other diseases with similar pathological characteristics of microcirculation disorders, including acute rejection of xeno- or allograft transplantation and fetal loss syndrome, in which studies show fgl2 plays an important role.

Animals↗
PubMed2006

[Construction of the p-mfgl2shRNA and its effect on mfgl2 expression in vitro].

OBJECTIVE: To construct the siRNA plasmid for mfgl2 gene, which has been reported to be involved in a variety of disease developments including fulminant viral hepatitis, acute rejection of allo/zero transplantation and fetal loss syndrome, and to investigate its inhibitory effects on mfgl2 expression in vitro. METHODS: A plasmid p-mfgl2shRNA complimentary to the sequence responsible for the functional domain of mouse fgl2 (mfgl2) was constructed. The pcDNA3.1 mfgl2 expression construct was able to show a satisfactory fgl2 protein expression. The plasmid expression pEGFP and a construct expressing irrelevant shRNA with a random combination of the p-mfgl2shRNA sequence were used as controls. A pEGFP-mfgl2 expressing mfgl2-EGFP fusion protein was also constructed for screening of the effect of p-mfgl2shRNA on the mfgl2 expression. RESULTS: Cotransfection of p-mfgl2shRNA with pEGFP-mfgl2 decreased green fluorescent cells and the lightness of fluorescence within the cells at the 24 h, 48 h and 72 h post-transfection when compared with that in the control groups which were solely transfected with pEGFP-mfgl2. Furthermore the mfgl2 expression was significantly reduced when the pcDNA3.1 mfgl2 expression construct was cotransfected with p-mfgl2shRNA both at mRNA level by RT-PCR and protein level by RT-PCR, immunohistochemistry staining and FACS in both CHO cell and Hela cell lines. CONCLUSIONS: The study demonstrated that the construct of p-mfgl2shRNA successfully interfered in the mfgl2 expression in vitro. It provides a basis for a further investigation of effect in vivo.

Animals↗
PubMed2005

The N-terminal octapeptide acts as a dimerization inhibitor of SARS coronavirus 3C-like proteinase.

The 3C-like proteinase of severe acute respiratory syndrome (SARS) coronavirus has been proposed to be a key target for structural-based drug design against SARS. Accurate determination of the dimer dissociation constant and the role of the N-finger (residues 1-7) will provide more insights into the enzyme catalytic mechanism of SARS 3CL proteinase. The dimer dissociation constant of the wild-type protein was determined to be 14.0microM by analytical ultracentrifugation method. The N-finger fragment of the enzyme plays an important role in enzyme dimerization as shown in the crystal structure. Key residues in the N-finger have been studied by site-directed mutagenesis, enzyme assay, and analytical ultracentrifugation. A single mutation of M6A was found to be critical to maintain the dimer structure of the enzyme. The N-terminal octapeptide N8 and its mutants were also synthesized and tested for their potency as dimerization inhibitors. Peptide cleavage assay confirms that peptide N8 is a dimerization inhibitor with a K(i) of 2.20mM. The comparison of the inhibitory activities of N8 and its mutants indicates that the hydrophobic interaction of Met-6 and the electrostatic interaction of Arg-4 contribute most for inhibitor binding. This study describes the first example of inhibitors targeting the dimeric interface of SARS 3CL proteinase, providing a novel strategy for drug design against SARS and other coronaviruses.

Binding Sites↗
PubMed2005

Fibrinogen-like protein 2 fibroleukin expression and its correlation with disease progression in murine hepatitis virus type 3-induced fulminant hepatitis and in patients with severe viral hepatitis B.

AIM: To evaluate the expression of fibrinogen-like protein 2 (fgl2) and its correlation with disease progression in both mice and patients with severe viral hepatitis. METHODS: Balb/cJ or A/J mice were infected intraperitoneally (ip) with 100 PFU of murine hepatitis virus type 3 (MHV-3), liver and serum were harvested at 24, 48, and 72 h post infection for further use. Liver tissues were obtained from 23 patients with severe acute chronic (AOC) hepatitis B and 13 patients with mild chronic hepatitis B. Fourteen patients with mild chronic hepatitis B with cirrhosis and 4 liver donors served as normal controls. In addition, peripheral blood mononuclear cells (PBMC) were isolated from 30 patients (unpaired) with severe AOC hepatitis B and 10 healthy volunteers as controls. Procoagulant activity representing functional prothrombinase activity in PBMC and white blood cells was also assayed. A polyclonal antibody against fgl2 was used to detect the expression of both mouse and human fgl2 protein in liver samples as well as in PBMC by immunohistochemistry staining in a separate set of studies. Alanine aminotransferase (ALT) and total bilirubin (TBil) in serum were measured to assess the severity of liver injury. RESULTS: Histological changes were found in liver sections 12-24 h post MHV-3 infection in Balb/cJ mice. In association with changes in liver histology, marked elevations in serum ALT and TBil were observed. Mouse fgl2 (mfgl2) protein was detected in the endothelium of intrahepatic veins and hepatic sinusoids within the liver 24 h after MHV-3 infection. Liver tissues from the patients with severe AOC hepatitis B had classical pathological features of acute necroinflammation. Human fgl2 (hfgl2) was detected in 21 of 23 patients (91.30%) with severe AOC hepatitis B, while only 1 of 13 patients (7.69%) with mild chronic hepatitis B and cirrhosis had hfgl2 mRNA or protein expression. Twenty-eight of thirty patients (93.33%) with severe AOC hepatitis B and 1 of 10 with mild chronic hepatitis B had detectable hfgl2 expression in PBMC. No hfgl2 expression was found either in the liver tissue or in the PBMC from normal donors. There was a positive correlation between hfgl2 expression and the severity of the liver disease as indicated by the levels of TBil. PCA significantly increased in PBMC in patients with severe AOC hepatitis B. CONCLUSION: The molecular and cellular results reported here in both mice and patients with severe viral hepatitis suggest that virus-induced hfgl2 prothrombinase/fibroleukin expression and the coagulation activity associated with the encoded fgl2 protein play a pivotal role in initiating severe hepatitis. The measurement of hfgl2/fibroleukin expression in PBMC may serve as a useful marker to monitor the severity of AOC hepatitis B and a target for therapeutic intervention.

Animals↗
PubMed2004

Association between IL-13 gene polymorphism and asthma in Han nationality in Hubei Chinese population.

In order to investigate whether Arg110Gln polymorphism in the coding region of the IL-13 gene is associated with asthma and total plasma IgE level in Han nationality in Hubei Chinese population, the allele frequency of 4257(g/a) site and Arg110Gln genotype of IL-13 was detected by using restriction fragment length polymorphism in Han nationality in Hubei Chinese population including 43 asthmatic children, 45 asthmatic adults, 31 control children and 46 control adults. Total plasma IgE was measured by Chemiluminescence assay. The results showed that the frequency of allele A at 4257 bp of IL-13 in children and adults was 0.39 and 0.32, respectively. The GlnGln form of Arg110Gln polymorphism of IL-13 gene was associated with susceptibility of asthma and elevated total plasma IgE in children (P=0.030 and 0.0009, respectively), but not with them in adults (P=0.219 and 0.174, respectively). Our results suggest that the Arg110Gln polymorphism of IL-13 gene is associated with susceptibility of asthma and elevated total plasma IgE in Chinese children of Han nationality in Hubei, but not with them in adults.

Adult↗
PubMed2004

[Hfgl2/fibroleukin expression in liver and peripheral blood mononuclear cells (PBMC) and its correlation with disease severity].

OBJECTIVE: Viral hepatitis remains a major public health problem and the most common type of liver disease worldwide. There are an increasing number of patients with chronic hepatitis B who develop acute hepatitis on chronic condition (AOC) and die of acute hepatic failure both as a result of lack of understanding of the pathogenesis of the disease and lack of effective treatment. The hallmark of AOC is the extreme rapidity of the necromicroinflammatory process resulting in widespread or total hepatocellular necrosis in weeks or even days. Our previous studies have shown in an experimental animal model of fulminant viral hepatitis caused by murine hepatitis virus strain 3, the importance of macrophage activation, and expression of a unique gene mfgl 2 which encodes a serine protease capable of directly cleaving prothrombin to thrombin, resulting in widespread fibrin deposition within the liver and hepatocyte necrosis. The undergoing study in this report is designed to identify the role of hfgl 2 (human fibrinogen like protein 2) /fibroleukin in patients with viral hepatitis. METHODS: Liver tissues were obtained from 23 patients with AOC hepatitis B, and from 13 patients with inactive chronic hepatitis B (CHB) and 14 patients with chronic hepatitis B with cirrhosis during the year of 1995 to the end of 2001. Liver biopsies were performed within 30 min after the patients were diagnosed with death as a result of acute hepatic failure. Liver samples were also obtained from 4 liver donors as normal controls. In addition, peripheral blood mononuclear cells (PBMC) were isolated from 30 patients (unpaired) with AOC hepatitis B and 10 patients with CHB during the May of 2001 to March of 2002 and 10 healthy volunteer as negative control. PBMCs were freshly isolated and smeared on slides and kept at -80 degree C for further use. Histological sections were stained with hemotoxylin and eosin. A 169 bp of hfgl 2 cDNA probe and a polyclonal or monoclonal antibody against hfgl 2 were used to detect the expression of hfgl 2 mRNA and protein in liver samples as well as PBMC by immune histochemistry separately. RESULTS: Liver tissues from the patients with acute on chronic hepatitis had classical pathological features of acute necroinflammation. Hfgl 2 was detected by immune histochemistry in 21 of 23 patients (91.3%) in liver sections from patients with acute on CHB, while only 1 of 13 patients (7.7%) with CHB and cirrhosis and no evidence of active disease had hfgl 2 mRNA or protein expression. 28 of 30 patients (93.3%) with acute on CHB and 1 of 10 with CHB were detected with hfgl 2 expression in PBMC. There was no hfgl 2 expression in either the liver tissue or the PBMC from the normal donors. There was positive correlation of hfgl 2 expression and the severity of the disease displayed by the value of bilirubin and PT. CONCLUSION: The molecular and cellular results reported here in patients with acute on chronic hepatitis and who died of acute hepatic failure correlates with previous report in 8 patients with fulminant hepatic failure (FHF) and mimic closely the changes observed in the murine model of fulminant viral hepatitis in which the pathogenesis of the disease has been studied in a stepwise fashion. This study further suggests that virus induced hfgl 2 prothrombinase/fibroleukin expression and the potent function of the protein it encodes plays a pivotal role in initiating acute severe hepatitis on the baseline of chronic hepatitis. The measurement of hfgl 2/fibroleukin expression in PBMC may serve as a useful marker to monitor the severity of disease in patients with the AOC hepatitis B and a target for therapeutic intervention.

Adolescent↗
PubMed2003

[Expression of human fibroleukin gene acute on chronic hepatitis B and its clinical significance].

OBJECTIVE: To investigate the mRNA and protein expressions of human fibroleukin gene (hfg12) in acute on chronic (AOC) hepatitis B and its clinical significance. METHODS: Liver tissues were obtained from 23 patients with AOC hepatitis B, 13 patients with chronic hepatitis, and 14 patients with cirrhosis to be examined histologically. Immunohistochemistry and in situ hybridization were used to detect the mRNA and protein expressions of hfg12 in the liver tissues. Double staining was used to the hfg12 positive samples to examine both the hfg12 and fibrin. Four specimens of liver tissue from normal donors were used as controls. RESULTS: Immunohistochemistry showed that hfg12 was expressed in the liver tissues of 21 out of the 23 patients with AOC hepatitis B (91.30%) and only one out of the 13 patients with chronic hepatitis (7.69%). In situ hybridization showed that hfg12 was expressed in the liver tissues of 13 out of he 23 patients with AOC hepatitis B and in none of the 27 patients with chronic hepatitis or cirrhosis. In patients with AOC hepatitis Kupffer's cell, CD68 positive, was numerous and big, mainly distributed in the necrosis areas. It was identified as the same of hfg12-expressing cells. CONCLUSION: High expression of hfg12 is one of the molecular mechanisms of necrosis of liver cells in AOC hepatitis.

Adolescent↗