The association between the genetic polymorphisms of LMP2/LMP7 and the outcomes of HCV infection among drug users

Objective：To investigate a possible association of LMP2/LMP7 genes with chronic hepatitis C virus（HCV） infection,and to assess whether LMP2/LMP7 genes could influence the outcomes of HCV infection among drug users.Methods：Genomic DNAs of 362 anti-HCV sero-positive drug users and 225 control drug users were extracted from the peripheral blood leukocytes.The sero-positive patients were divided into those who had persistent infection and those who had spontaneously cleared the infection.Polymorphisms of LMP genes were determined by PCR combined with restriction fragment length polymorphism（RFLP）.Results：The distribution of LMP2 genotypes among the control,persistent infection and spontaneous clearance groups were not different.However,the LMP7 codon 145 Gln/Lys,Lys/Lys,and Gln/Lys＋Lys/Lys genotypes were found significantly more frequent in the persistent infection group than in control group（OR=1.75,95%CI=1.06～2.90;OR=3.16,95%CI=1.23-8.12;OR=1.94,95%CI=1.21-3.12,respectively）.Similarly,the frequencies of the codon 145 Gln/Lys,Lys/Lys,and Gln/Lys＋Lys/Lys genotypes were found significantly more frequent in the persistent infection group than in the spontaneous clearance group（OR=1.64,95%CI=1.04-2.57;OR=2.40,95%CI=1.09-5.28;OR=1.76,95%CI=1.152.69,respectively）.Stratified analysis indicated that combined genotype Gln/Lys＋Lys/Lys of the LMP7 gene was related to an increasing susceptibility to HCV infection（OR=1.91,95%CI=1.02-3.55;OR=2.19,95%CI=1.243.89;OR=1.91,95%CI=1.05-3.48,OR=2.86,95%CI=1.41-5.78,respectively）and the risk of persistent HCV infection（OR=1.94,95%CI=1.12-3.34;OR=2.02,95%CI=1.21-3.38;OR=1.78,95%CI=1.12-2.85,OR=2.23,95%CI=1.09-4.58,respectively）among30-year-old,males,the injection drug user（IDU）subjects and/or the shorter duration drug users（≤5 y）.Conclusion：These results suggest that polymorphism of the LMP7 gene may have an influence on the outcomes of HCV infection,and is one of the factors accounting for the genetic susceptibility to HCV infection among drug users.

Screening Helicobacter pylori genes induced during infection of mouse stomachs

AIM:To investigate the effect of in vivo environment on gene expression in Helicobacter pylori(H.pylori) as it relates to its survival in the host.METHODS:In vivo expression technology(IVET) systems are used to identify microbial virulence genes.We modified the IVET-transcriptional fusion vector,pIVET8,which uses antibiotic resistance as the basis for selection of candidate genes in host tissues to develop two unique IVET-promoter-screening vectors,pIVET11 and pIVET12.Our novel IVET systems were developed by the fusion of random Sau3A DNA fragments of H.pylori and a tandem-reporter system of chloramphenicol acetyltransferase and beta-galactosidase.Additionally,each vector contains a kanamycin resistance gene.We used a mouse macrophage cell line,RAW 264.7 and mice,as selective media to identify specific genes that H.pylori expresses in vivo.Gene expression studies were conducted by infecting RAW 264.7 cells with H.pylori.This was followed by real time polymerase chain reaction(PCR) analysis to determine the relative expression levels of in vivo induced genes.RESULTS:In this study,we have identified 31 in vivo induced(ivi) genes in the initial screens.These 31 genes belong to several functional gene families,including several well-known virulence factors that are expressed by the bacterium in infected mouse stomachs.Virulence factors,vacA and cagA,were found in this screen and are known to play important roles in H.pylori infection,colonization and pathogenesis.Their detection validates the efficacy of these screening systems.Some of the identified ivi genes have already been implicated to play an important role in the pathogenesis of H.pylori and other bacterial pathogens such as Escherichia coli and Vibrio cholerae.Transcription profiles of allivi genes were confirmed by real time PCR analysis of H.pylori RNA isolated from H.pylori infected RAW 264.7 macrophages.We compared the expression profile of H.pylori and RAW 264.7 coculture with that of H.pylori only.Some genes such as cag A,vac A,lpx C,mur I,tlp C,trx B,sod B,tnp B,pgi,rbf A and inf B showed a 2-20 fold upregulation.Statistically significant upregulation was obtained for all the above mentioned genes(P < 0.05).tlp C,cag A,vac A,sod B,rbf A,inf B,tnp B,lpx C and mur I were also significantly upregulated(P < 0.01).These data suggest a strong correlation between results obtained in vitro in the macrophage cell line and in the intact animal.CONCLUSION:The positive identification of these genes demonstrates that our IVET systems are powerful tools for studying H.pylori gene expression in the host environment.

Cloning and characterization of a novel barley gene,HvORG4,induced by Fusarium graminearum infection

Barley Fusarium head blight(FHB),caused by species of the Fusarium fungus,is a devastating disease that is reemerging worldwide in recent years.In this study,a novel gene,HvORG4,was cloned from barley by using cDNA library and suppression subtractive hybridization(SSH) library strategies.The SSH library and cDNA library were constructed from the Chinese barley cultivar Jing02-461(resistance to FHB) infected by Fusarium graminearum isolate Huanggang-1.For the SSH analysis,more than 120 differentially expressed cDNAs were identified and sequenced.One of them showed high homology to the AtORG4 gene and was used as a probe to screen the cDNA library of Jing02-461.Six positive clones were identified and one of them contained a full-length cDNA,which was named HvORG4.Sequence analysis showed that HvORG4 encoded a deduced basic protein of 197 amino acids.Northern blotting analysis showed that HvORG4 was constitutively expressed in root and stalk,not in leaf or spike,and strongly induced in barley spikelets in response to infection with F.graminearum isolate Huanggang-1.Its homology and expression profile suggest that the HvORG4 might function as a transcription factor,playing an important role in signal transduction pathway for defense against FHB in barley.

Association of NOD1 and NOD2 genes polymorphisms with Helicobacter pylori related gastric cancer in a Chinese population

AIM:To investigate the association between the tag single nucleotide polymorphisms(TagSNPs) of NOD1 and NOD2 and the risk of developing gastric cancer.METHODS:We conducted a hospital-based case-control study including 296 incident gastric cancer patients and 160 gastritis controls.Eight TagSNPs in the NOD1 and NOD2 genes were selected from the Hapmap database using the haploview software and genotyped by the Sequenom MassArray system.The serum levels of anti-Helicobacter pylori(H.pylori) IgG were measured by enzyme-linked immunosorbent assay to indicate H.pylori infection.The odds ratios(OR) and 95% confidence intervals(CI) were calculated by unconditional logistic regression,including sex and age as confounding factors.RESULTS:The NOD1 rs2907749 GG genotype showed a decreased risk for gastric cancer(OR 0.50,95% CI:0.26-0.95,P = 0.04) while the rs7789045 TT genotype showed an increased risk(OR 2.14,95% CI:1.20-3.82,P = 0.01).An elevated susceptibility to gastric cancer was observed in the subjects with H.pylori infection and the NaOD1 rs7789045 TT genotype(OR 2.05,95% CI:1.07-3.94,P = 0.03) or the NOD2 rs7205423 GC genotype(OR 2.52,95% CI:1.05-6.04,P = 0.04).Haplotype analysis suggested that the distribution of AGT(rs2907749,rs2075820 and rs7789045) in NOD1 between the cases and control groups was significantly different(P corrected:0.04),and the diplotype AGT/AGT was associated with an elevated gastric cancer risk(OR 1.98,95% CI:1.04-3.79,P = 0.04).The association of the NOD1 rs7789045 TT genotype and the diplotype AGT/AGT was significant with H.pylori-related diffuse-type gastric cancer(OR 3.00,95% CI:1.38-6.53,P = 0.01;OR 4.02,95% CI:1.61-10.05,P < 0.01,respectively).CONCLUSION:Genetic polymorphisms in NOD1 and NOD2 may interact with H.pylori infection and may play important roles in promoting the development of gastric cancer in the Chinese population.