Biological Function of CysR Domain of ADAMTS13 / 中国实验血液学杂志

OBJECTIVE@#To investigate the biological function of Cysteine rich (CysR) domain of a disintegrin and metalloprotease with thrombospondin type 1 repeats-13 (ADAMTS13) on cleavage of von Willebrand factor (vWF) and provide experimental evidence for exploring the pathogenesis of thrombotic thrombocytopenic purpura (TTP).@*METHODS@#The six amino acids (EDGTLS) in ADAMTS13 CysR domain were point mutated one by one, and the mutant ADAMTS13 proteins were expressed and purified. The cleavage products of vWF polymer by wild-type or mutant ADAMTS13 under denaturing condition or shear stress were separated by 1% SeaKem HGT agarose gel and detected by Western blot.@*RESULTS@#The mutant ADAMTS13 plasmids (M1: Glu515Ala; M2: Asp516Ala; M3: Gly517Ala; M4: Thr518Ala; M5: Leu519Ala; M6: Ser520Ala) were successfully constructed and the proteins of wild-type and mutant ADAMTS13 were purified. Wild-type ADAMTS13 almost completely cleaved the vWF polymer under denaturing condition, while the cleavage activity of M1 mutant was significantly reduced in the same condition (P<0.01). The cleavage activity of M1 mutant of ADAMTS13 was also significantly reduced compared with that of the wild-type under shear stress (P<0.01). The activity of M1 mutant to cleave the FRETS-vWF73 was dramatically reduced compared with that of wild-type ADAMTS13. However, the binding ability of M1 mutant to vWF was similar with that of wild-type ADAMTS13.@*CONCLUSION@#The CysR domain of ADAMTS13 plays an important role in the digestion of vWF under denaturing condition and shear stress. The Glu515 amino acid residue might be an important site for substrate recognition.

Caffeine-induced endothelial cell death and the inhibition of angiogenesis / 대한해부학회지

Numerous studies have shown that adenosine or adenosine agonists can stimulate angiogenesis. However, the effect of caffeine (a known adenosine receptor antagonist) on angiogenesis has not been previously studied. Accordingly, this study was undertaken to examine the effect of caffeine on angiogenesis and to clarify the mechanism involved. Chick chorioallantoic membrane assays were used to investigate the effect of caffeine on angiogenesis and proliferation assays using human umbilical vein endothelial cells (HUVECs), were used to study its effects on specific aspects of angiogenesis. The expressions of caspase-3 and Bcl-2 were examined by western blotting, immunofluorescence staining was used to identify HUVEC morphological changes, and fluorescence activated cell sorting (FACS) and DAPI staining were used to detect HUVEC apoptosis. Caffeine was found to inhibit blood vessel formation dose-dependently and to inhibit the proliferation of HUVECs time- and dose-dependently. FACS analysis and DAPI staining showed that inhibitory effect of caffeine on HUVEC proliferation was the result of apoptosis and the up-regulation of thrombospondin-1 (TSP-1). Furthermore, TSP-1 levels were down-regulated by NECA but were unaffected by CGS21680, indicating that caffeine regulated TSP-1 expression via adenosine A2B receptor. In addition, caffeine up-regulated caspase-3 and down-regulated Bcl-2 at the protein level. These results suggest that the inhibitory effect of caffeine on angiogenesis is associated, at least in part, with its induction of endothelial cell apoptosis, probably mediated by a caspase-3 dependent mechanism.

Analysis of the Monocyte Chemoattractant Protein 1 -2518 Promoter Polymorphism in Korean Patients with Alopecia Areata

Monocyte chemoattractant protein-1 (MCP-1) levels are increased in scalp lesions of patients with alopecia areata (AA), suggesting a role in the development of AA. Recently, a biallelic A/G polymorphism in the MCP-1 promoter at position -2518 has been found, influencing the level of MCP-1 expression in response to an inflammatory stimulus. We investigated whether the presence of these polymorphisms were associated with AA in Korean population. 145 Korean patients with AA, 246 healthy subjects without clinical evidence of AA were screened for genotype with a PCR-based assay. In the AA patients the frequency of the A and G alleles was 40.3 and 59.7%, respectively and the distribution of the A/A, A/G and G/G genotypes was 19.3, 42.1 and 38.6%, respectively. Amongst the controls the frequency of the A and G alleles was 39.8 and 60.2%, and the distribution of the A/A, A/G, G/G genotypes in the same group was 17.5, 44.7 and 37.8%, respectively. There was no significant difference in the allele frequencies and genotype distributions between the patients and the controls (p=0.889, p=0.848, respectively). Our data indicates that no association exists between the -2518A/G polymorphism of the MCP-1 gene and susceptibility to alopecia areata.

Polymorphism of UDP-glucuronosyltransferase Gene(UGT1A1) of Neonatal Hyperbilirubinemia in Korea / 소아과

PURPOSE: The incidence of neonatal hyperbilirubinemia is twice as high in East Asians as in whites and its metabolic basis has not been clearly explained. Recently, UDP-glucuronosyltransferase gene (UGT1A1) mutation was found to be a risk factor of neonatal hyperbilirubinemia in Japanese and Taiwanese Chinese. We studied whether neonatal hyperbilirubinemia is associated with mutation of UGT1A1, which is a key enzyme of bilirubin catabolism, in Korean. METHODS: The genomic DNA was isolated from 45 Korean full term neonates who had hyperbilirubinemia(serum bilirubin >12 mg/dL) with no obvious causes, and the 64 Korean neonates of the control population. We detected a missense mutation of Gly71Arg of UGT1A1 gene by using allele-specific polymerase chain reaction. Polymorphism was confirmed by direct sequencing. RESULTS: Two of the 45 neonates with serum bilirubin above 12 mg/dL had homozygous mutation and 16 neonates had heterozygous mutation. Two of the 31 neonates with serum bilirubin above 15 mg/dL had homozygous mutation and 13 neonates had heterozygous mutation. Thirteen of the control group had heterozygous mutation and homozygous mutation was not found. Allele frequency of Gly71Arg mutation in hyperbilirubinemia group was 0.22, which was significantly higher than 0.11 in the control group(P<0.0144). CONCLUSION: The missense mutation causing Gly71Arg of UGT1A1 was detected in the Korean neonatal hyperbilirubinemia. The high frequency of this missense mutation may be attributed to the high prevalence of hyperbilirubinemia in the Korean.

Expression Profiles of Immune-related Genes in Fluoxetine-treated Human Mononuclear Cells by cDNA Microarray

To investigate the effect of fluoxetine, one of selective serotonin reuptake inhibitors (SSRIs), on the immune system, human peripheral blood mononuclear cells (PBMC) were treated with fluoxetine (10 7 M) for 24 h, and immune-related genes were analyzed by cDNA microarray. Expression of the immune- related genes such as CD107b (LAMP-2), CD47 receptor (thrombospondin receptor), CD5 antigen-like (scavenger receptor cysteine rich family), copine III (CPNE3), interleukin (IL) -18 (interferon-gamma- inducing factor), integrin alpha 4 (CD49d), integrin alpha L subunit (CD11a), IL-3 receptor alpha subunit, L apoferritin, and small inducible cytokine subfamily A (Cys-Cys) member 13 (SCYA13) was induced by fluoxetine. This result suggests that fluoxetine may affect the immune system, and provides fundamental data for the involvement of SSRIs on immunoregulation.

Angiotensin converting enzyme gene polym orphism in Korean patients with primary knee osteoarthritis

Angiotensin converting enzyme (ACE) plays an important role in the physiology of vasculature, blood pressure and inflammation. ACE gene, known to have insertion/deletion (I/D) polymorphism, has been widely investigated in its relation with cardiovascular and neurodegenerative diseases and longevity. ACE gene polymorphism in an inflammation associated osteoarthritis (OA) patients is not known. Here we have investigated ACE gene polymorphism in 142 Korean primary knee OA patients and 135 healthy volunteers to establish any clinical correlates between ACE polymorphism and knee osteoarthritis. Clinical parameters such as disease onset age, Kellgren-Lawrence grade and Lequesne's functional index provided additional analysis of the relationship of ACE polymorphism and clinical features of OA. Early onset OA showed significantly higher allele frequency and carriage rate of I than late onset OA. Radiographically severe and functionally poor OA showed higher carriage rate of I allele than radiographically mild and functionally good OA, respectively. This study first reports ACE gene polymorphism to be a risk factor for early onset, severe form primary knee OA.