Biomedical subjects

Hua-Lin Wu

Publications and source records attributed to Hua-Lin Wu.

7 recordsLinked to original sources

PubMed2003

Thrombomodulin-mediated cell adhesion: involvement of its lectin-like domain.

Thrombomodulin (TM) is an integral membrane glycoprotein that is a potent anticoagulant factor. TM may also possess functions distinct from its anticoagulant activity. Here the influence of TM on cell adhesion was studied in TM-negative melanoma A2058 cells transfected with green fluorescent protein-tagged TM (TMG) or lectin domain-deleted TM (TMG(DeltaL)). Confocal microscopy demonstrated that both TMG and TMG(DeltaL) were distributed in the plasma membrane. TMG-expressed cells grew as closely clustered colonies, with TM localized prominently in the intercellular boundaries. TMG(DeltaL)-expressed cells grew singly. Overexpression of TMG, but not TMG(DeltaL), decreased monolayer permeability in vitro and tumor growth in vivo. The cell-to-cell adhesion in TMG-expressed cells was Ca2+-dependent and was inhibited by monoclonal antibody against the lectin-like domain of TM. The effects of TM-mediated cell adhesion were abolished by the addition of mannose, chondroitin sulfate A, or chondroitin sulfate C. In addition, anti-lectin-like domain antibody disrupted the close clustering of the endogenous TM-expressed keratinocyte HaCaT cell line derived from normal human epidermis. Double-labeling immunofluorescence staining revealed similar distributions of TM and actin filament in the cortex region of the TMG-expressed cells. Thus, TM can function as a Ca2+-dependent cell-to-cell adhesion molecule. Binding of specific carbohydrates to the lectin-like domain is essential for this specific function.

Calcium↗

PubMed2003

Synergistic effect of stromelysin-1 (matrix metallo-proteinase-3) promoter 5A/6A polymorphism with smoking on the onset of young acute myocardial infarction.

The objective of this study was to elucidate the association between the polymorphism of stromelysin-1, also called matrix metalloproteinases-3 (MMP-3), and smoking in the pathogenesis of young acute myocardial infarction (MI). Plaque rupture is well established as a critical factor in the pathogenesis of acute MI. MMP-3 can degrade extracellular matrix and are identified extensively in human coronary atheroslcerotic plaques, and may contribute to the weakening of the cap and subsequent rupture. We studied 150 consecutive patients with acute MI onset at age under 45 years (84% men) and 150 sex- and age-matched control subjects. 5A/6A genotype in the stromelysin-1 promoter was determined using polymerase chain reaction and direct sequencing. Results show that the frequency of the 5A allele and the prevalence of 5A/5A + 5A/6A genotypes were both significantly higher in the young MI than the control group (35.0% vs. 20.0%, odds ratio [OR] 2.15, 95% confidence interval [CI] 1.30 to 6.80, p<0.001; 44.7% vs. 27.4%, OR 2.19, 95% CI 1.21 to 3.98, p=0.009). Multiple logistic regression analysis showed that the 5A allele was an independent risk factor (OR 2.36, 95% CI 1.24 to 5.90, p=0.008) as were as smoking (OR 3.92, 95% CI 1.75 to 9.21, p=0.001), diabetes mellitus (OR 3.51, 95% CI 1.41 to 6.32, p=0.0068) and hypertension (OR 1.85, 95% CI 1.35 to 4.33, p=0.0025) for the premature onset of MI. Compared to 6A/6A subjects, among patients who did not smoke, the 5A allele polymorphism was associated with a higher risk of MI at a young age (OR 2.69, 95% CI 1.3 to 8.6), but smoking carriers of the 5A allele had a significantly 10-fold higher risk of MI (OR 9.98, 95% CI 2.3 to 12.5). We can conclude that there was a significant association between the 5A/6A polymorphism in the promoter region of stromelysin-1 gene and young MI in Taiwan. A synergistic effect between smoking and this polymorphism for the premature onset of MI had been shown in this study.

Adult↗

PubMed2002

The angiogenesis inhibitor protease-activated kringles 1-5 reduces the severity of murine collagen-induced arthritis.

During rheumatoid arthritis there is enlargement and increased cellularity of the synovial lining of joints, before invasion by the synovium of the underlying cartilage and bone. This increased tissue mass requires a network of blood vessels to supply nutrients and oxygen. Disruption of synovial angiogenesis is thus a desirable aim of antiarthritic therapies. Protease-activated kringles 1-5 (K1-5) is an angiogenesis inhibitor related to angiostatin. In common with angiostatin, K1-5 contains the first four kringle domains of plasminogen, but also encompasses the kringle 5 domain, which confers enhanced antiangiogenic activity when compared with angiostatin. The purpose of the present study was to assess the effect on murine arthritis of K1-5. Arthritis was induced in DBA/1 mice by a single injection of bovine collagen. Treatment with K1-5 was commenced on the day of arthritis onset and continued for 10 days, until the end of the experiment. Daily intraperitoneal administration of K1-5 (2 mg/kg body weight) significantly reduced both paw swelling and clinical score (a composite index of the number of arthritic limbs and the severity of disease). The clinical efficacy of this treatment was reflected by a reduction in joint inflammation and destruction, as assessed histologically. These data suggest that antiangiogenic therapies, which block formation of new blood vessels and hence reduce synovial expansion, might be effective in treating rheumatoid arthritis.

Angiogenesis Inhibitors↗

PubMed2002

Identification of functionally important residues of the epidermal growth factor-2 domain of factor IX by alanine-scanning mutagenesis. Residues Asn(89)-Gly(93) are critical for binding factor VIIIa.

This paper describes the consequences of alanine-scanning mutagenesis on 28 positions of the second epidermal growth factor (EGF-2) domain of factor IX. We identified four positions of Gln(97), Phe(98), Tyr(115), and Leu(117) that are critical for secretion of factor IX. Of the remaining mutations, 4 mutants (V86A, E113A, K122A, and S123A) are as active as wild-type factor IX (IXwt); 16 (D85A, K100A, N101A, D104A, N105A, R116A, E119A, T87A, I90A, K91A, R94A, E96A, S102A, K106A, T112A, and N120A) retain reduced but detectable activity, and 4 (N89A, N92A, G93A, and V107A) are nearly inert in the clotting assay. Both factor XIa and the factor VIIa-tissue factor complex effectively catalyzed the activation of these mutants except N89A. The mutant V107A failed to form the factor tenase complex with factor VIIIa because of a 35-fold increase in K(d). The mutants N89A and N92A did not compete with factor IXwt for factor VIIIa binding, and G93A exhibited a 6-fold increase in K(i) values in the competitive binding assay. It appears that mutations at these positions have significantly affected the interaction between factor IX and factor VIIIa, although other mutations had little effect on the binding of factor IX to factor VIIIa. Mutations in two regions, Thr(87)-Gly(93) and Asn(101)-Val(107), significantly increased the K(m) value of factor IXa (2-10-fold) in cleavage of factor X in the absence of factor VIIIa. In the presence of factor VIIIa, the catalytic efficiency of each mutant toward factor X paralleled its clotting activity. Briefly, we propose two relatively distinctive functions of factor IX for two adjacent regions in the EGF-2 domain; the first loop region (residues 89-94) is involved with the binding of its cofactor, factor VIIIa, and the third loop with connected beta-sheets (residues 102-108) is involved in the proper binding to the substrate, factor X.

Alanine↗

PubMed2002

Decrease of fibrinolytic activity in human endothelial cells by arsenite.

Blackfoot disease (BFD) is an endemic peripheral vascular occlusive disease that occurred in the southwest coast of Taiwan. It is believed that arsenic in the drinking water from artesian wells plays an important role in the development of the disease. We have previously shown that BFD patients had significant lower tissue-type plasminogen activator (t-PA) antigen level and higher plasminogen activator inhibitor, Type 1 (PAI-1) antigen level than normal controls. The purpose of this study was to investigate the effects of arsenite on the fibrinolytic and anticoagulant activities of cultured macrovascular and microvascular endothelial cells. Incubation of human microvascular endothelial cells (HMEC-1), but not human umbilical vein endothelial cells (HUVECs), with arsenite caused a decrease of t-PA mRNA level, a rise of both PAI-1 mRNA level and PAI activity. Arsenite could also inhibit the thrombomodulin (TM) mRNA expression and reduce the TM antigen level in HMEC-1. In conclusion, arsenite had a greater effect on HMEC-1 as compared to HUVECs in lowering the fibrinolytic activity and may be responsible for the reduced capacity of fibrinolysis associated with BFD.

Arsenites↗

PubMed2002

Synergistic effect of thrombomodulin promoter -33G/A polymorphism and smoking on the onset of acute myocardial infarction.

Thrombomodulin is an endothelial cell surface receptor for thrombin. It plays an important role in the regulation of blood coagulation by decreasing thrombin activity and activating protein C. This study examined the possible association between the thrombomodulin -33G/A polymorphism and acute myocardial infarction. We recruited 278 patients (mean age 57.5 years, 241 men) with documented myocardial infarction and 450 age- and sex-matched control subjects. Polymerase chain reaction and single-strand conformation polymorphism was used to define the thrombomodulin -33G/A polymorphism. The frequency of the thrombomodulin GA+AA genotype among patients with myocardial infarction was higher than that in control subjects (22.7% vs. 16.2%, odds ratio [OR] 1.5, 95% confidence interval [CI] 1.0 to 2.2). The -33G/A polymorphism (GA+AA genotype) was significantly associated with myocardial infarction (OR 1.6, 95% CI 1.1 to 2.5) as was hypertension, diabetes mellitus and smoking. Among young myocardial infarction patients (age < or =45 years, n = 72), the frequency of -33G/A polymorphism was more significantly higher than that in control subjects (29.2% vs. 16.2%, OR 2.1, 95% CI 1.2 to 3.8). The -33G/A polymorphism (OR 2.3, 95% CI 1.3 to 4.1) and smoking (OR 4.5, 95% CI 2.5 to 7.9) were the only independent risk factors for young myocardial infarction. Furthermore, among patients who did not smoke, the polymorphism was associated with a nonsignificant increase in the risk of young myocardial infarction (OR 1.9, 95% CI 0.6 to 5.6); whereas, in the presence of smoking, the increase was statistically significant (OR 2.3, 95% CI 1.2 to 4.7). Smoking carriers of the thrombomodulin -33G/A polymorphism had a nearly 10-fold increased risk of young myocardial infarction (OR 9.8, 95% CI 4.3 to 22.4) when compared with nonsmoking non-carriers. We concluded that there was a significant association between the thrombomodulin -33G/A polymorphism and myocardial infarction in our population, especially in young patients. The clinical effect of this genetic factor was enhanced by smoking.

Adult↗

PubMedDate not supplied

Molecular evidence for transmission of GB virus-C/Hepatitis G virus infection within family: close relationship between mother and child.

BACKGROUND/AIMS: GBV-C/Hepatitis G virus (HGV) is transmitted parentally, but some of the transmitted routes are still unclear. This study was conducted to investigate the relationship of family members in the transmission of HGV. METHODOLOGY: The study group enrolled 11 children from four index mothers with HGV viremia, whereas the control group had 14 children from seven matched mothers without HGV infection. Detection of circulating HGV RNA and anti-E2 antibody was conducted. Comparison of partially HGV nucleotide sequences at the 5' non-coding and non-structure 5 regions was performed among the infected family members. RESULTS: There was higher HGV viremia in children from the index mothers with HGV infection than those from mothers in control (3/11 vs. 0/14, p < 0.05). Nucleotide sequences analysis showed higher similarity between mothers and their children in the same family (98.6% to 100%) than between mothers of different families (87.8% to 92.4%). The phylogenetic construction also demonstrated distinct sequence clusters for mother and child/children of each family. CONCLUSIONS: The relationship of HGV transmission between mother and children was closely related in family. Spread of HGV might occur intrafamilially.

Adolescent↗