RESUMEN

OBJECTIVE: To assess the association of vascular endothelial growth factor (VEGF) gene polymorphisms with susceptibility to Crohn's disease (CD) in a Chinese population. METHODS: For 275 CD patients and 495 controls, the genotypes of VEGF gene rs699947 and rs3025039 loci were determined with a SNaPshot method. RESULTS: The allelic and genotypic frequencies of the rs699947 and rs3025039 loci did not differ between the two groups (all P>0.05). By stratification analysis, allele A and genotype CA+AA of rs699947 were more frequent in patients with colonic CD compared with the controls (P=0.006, 95%CI:1.143-2.234; P=0.005, 95%CI:1.203-2.900, respectively). Compared with the controls, the allele A and genotype CA+AA of rs699947 were less frequent in patients with ileal lesions including ileal CD and ileocolonic CD (P=0.033, 95%CI:0.524-0.974;P=0.043, 95%CI:0.481-0.989, respectively). The frequency of TT homozygote of rs3025039 was lower in patients with non-stricturing and non-penetrating CD compared with the controls (P=0.036, 95%CI:0.016-0.870). CONCLUSION: Polymorphisms of the VEGF gene rs699947 locus may contribute to an increased risk for colonic CD, but may play a protective role in patients with ileal lesion. Individuals carrying the TT genotype for VEGF rs3025039 locus may be less susceptible to non-stricturing and non-penetrating CD.

Asunto(s)

RESUMEN

Fibroblast growth factor 21 (FGF21) as a member of the FGFs serves a key role in glucose homeostasis and protection of the liver, heart, kidney and skin from damage as well as cancer cell development. In addition, transcription of FGF21 is sensitive to diverse damages; however, the role of the transcriptional regulator of FGF21 in cancer cells remains to be elucidated. FGFs were identified to have dominant expression in cancer cells; therefore, mouse forestomach carcinoma (MFC) cells were used in the present study, which is a mouse stomach cancer cell strain for identifying the FGF21 regulators. In promoter analysis of FGF21, the putative transcription factor 4 (TCF4) binding motifs (T/AC/GAAAG) were observed within 1.5 kb of the promoter region. Further chromatin immunoprecipitation and yeast-one hybrid assays identified that TCF4 directly bound to one of the two putative binding motifs observed. A co-immunoprecipitation assay identified that ß-catenin interacts with TCF4 in MFC cells, and the ß-catenin/TCF4 complex bound to the promoter of FGF21. In order to examine the function of TCF4 and ß-catenin in transcriptional regulation of FGF21, TCF4 and ß-catenin was transiently expressed in MFC cells. Reverse transcription-quantitative polymerase chain reaction results revealed that overexpression of TCF4 and ß-catenin activated FGF21 transcription. Besides, suppression of ß-catenin via a specific short interfering RNA resulted in reduction of FGF21 expression. Together these findings suggest that the ß-catenin/TCF complex directly activates FGF21 via promoter binding. The observations of the present study may help elucidate the regulatory mechanism of FGF21, which is a key pharmaceutical protein.

RESUMEN

Vibrio vulnificus is a virulent human pathogen causing gastroenteritis and possibly life threatening septicemia in patients. Most V. vulnificus are catalase positive and can deactivate peroxides, thus allowing them to survive within the host. In the study presented here, a catalase from V. vulnificus (CAT-Vv) was purified to homogeneity after expression in Escherichia coli. The kinetics and function of CAT-Vv were examined. CAT-Vv catalyzed the reduction of H2O2 at an optimal pH of 7.5 and temperature of 35°C. The Vmax and Km values were 65.8±1.2 U/mg and 10.5±0.7 mM for H2O2, respectively. Mutational analysis suggests that amino acids involved in heme binding play a key role in the catalysis. Quantitative reverse transcription-PCR revealed that in V. vulnificus, transcription of CAT-Vv was upregulated by low salinity, heat, and oxidative stresses. This research gives new clues to help inhibit the growth of, and infection by V. vulnificus.

Asunto(s)

RESUMEN

The Lon protease is highly evolutionarily conserved. However, little is known about Lon in the context of gut microbial communities. A gene encoding a Lon-like protease (Lon-like-Ms) was identified and characterized from Methanobrevibacter smithii, the predominant archaeon in the human gut ecosystem. Phylogenetic and sequence analyses showed that Lon-like-Ms and its homologs are newly identified members of the Lon family. A recombinant form of the enzyme was purified by affinity chromatography, and its catalytic properties were examined. Recombinant Lon-like-Ms exhibited ATPase activity and cleavage activity toward fluorogenic peptides and casein. The peptidase activity of Lon-like-Ms relied strictly on Mg(2+) (or other divalent cations) and ATP. These results highlight a new type of Lon-like protease that differs from its bacterial counterpart.

Asunto(s)

RESUMEN

Embelin is a small-molecule inhibitor of X­linked inhibitor of apoptosis protein (XIAP), and it induces apoptosis in tumor cells via the inhibition of XIAP. The aim of the present study was to investigate the anticancer effect of embelin on human gastric carcinoma cells and the mechanisms underlying this effect. Cell proliferation of SGC7901 human gastric carcinoma cells was measured using MTT assay, following treatment with embelin (5, 10 and 15 µM) on days 1, 3 and 5. Caspase­3 and nuclear factor (NF)­κB p65 activation in SGC7901 cells were assessed using commercial kits. Cellular and nuclear apoptosis were analyzed with an Annexin V­FITC/PI Apoptosis Detection kit and DAPI staining assay, respectively. Phospho (p)­p38 mitogen­activated protein kinase (MAPK), p­inhibitor of NF­κB (p­IκBα) and p­IκB kinase α/ß (p­IKKα/ß) protein expression levels were analyzed with western blot assay. In the present study, treatment with embelin decreased cell proliferation, induced caspase­3 activation and suppressed NF­κB p65 activation in SGC7901 cells. Furthermore, embelin administration reduced p­IκBα and p­IKKα/ß protein expression levels. In conclusion, embelin induces cell apoptosis in human gastric carcinoma through activation of p38 MAPK and inhibition of the NF­κB signaling pathways. It was further suggested that embelin may be used as a potential drug for the treatment of gastric carcinoma.

Asunto(s)

RESUMEN

Increased levels of homocysteine are found systemically and in intestinal mucosa of patients with inflammatory bowel disease, and, specifically, in ulcerative colitis (UC). However, there are controversial reports regarding the factors contributing to increased levels of homocysteine in UC. Furthermore, little information is available regarding the relationship between hyperhomocysteinemia (HHcy), vitamin status, and genetic polymorphisms of homocysteine-related enzymes in these patients. This study examined four functional polymorphisms linked to homocysteine metabolism (MTHFR C677T and A1298C, MTR A2756G and MTRR A66G), and evaluated plasma levels of homocysteine, folate, and vitamin B(12) in 310 consecutive patients with UC and 936 age- and sex-matched healthy controls from southeast China. The variant allele and genotypic frequencies in MTHFR A1298C, MTR A2756G and MTRR A66G genes were significantly higher in patients with UC compared to healthy controls. Further, HHcy and low levels of folate and vitamin B(12) were more frequent in patients with UC. The MTR 2756G allele, extent of the disease, and gender were the independent determinants of HHcy in these patients. These findings suggest that genetic and nutritional factors have a synergetic effect on HHcy in patients with UC. In conclusion, our data highlight a prevention strategy for moderation of HHcy and supplementation with folate and vitamine B(12) in patients with UC from Southeast China.

Asunto(s)