RESUMO
BACKGROUND AND OBJECTIVES: One of the mechanisms proposed by which H. pylori causes gastric cancer (GC) is through DNA damage due to chronic inflammation. Genomic integrity is guaranteed by repair enzymes such as APE-1, OGG-1, and PARP-1. Host genetic polymorphisms associated with the bacterial strain may influence the ability to repair the damage, contributing to the development of H. pylori-associated GC. The aim of this study was to determine the association of the polymorphisms APE-1 (T2197G), OGG-1 (C1245G), and PARP-1 (A40676G) with H. pylori-genotype in 109 patients with GC. METHODS: Polymorphism was assessed by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) and H. pylori detection/genotyping by PCR. RESULTS: In the intestinal subtype, PARP-1 wild-type was more frequent (P=0.001) in patients >50 years old. The repair enzymes genotypes analyzed in combination showed that the less pathogenic strains are associated with the APE-1 polymorphic allele and, unexpectedly, with PARP-1 wild-type, but this last one associated with APE-1 polymorphic allele or in older patients. CONCLUSIONS: Our results indicate the importance of H. pylori and APE-1 genotypes in the gastric carcinogenesis. Also, support the hypothesis of a decrease of PARP-1 wild-type activity in older individuals. Taken together these data may be an important clue to understand the role of low-virulence strains of H. pylori in gastric carcinogenesis and point the importance to analyze the polymorphisms as a group.
Assuntos
Enzimas Reparadoras do DNA/genética , Helicobacter pylori/genética , Polimorfismo Genético , Neoplasias Gástricas/etiologia , Idoso , DNA Glicosilases/genética , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/genética , Genótipo , Helicobacter pylori/classificação , Humanos , Masculino , Poli(ADP-Ribose) Polimerase-1 , Poli(ADP-Ribose) Polimerases/genética , Neoplasias Gástricas/microbiologiaRESUMO
BACKGROUND: The kynurenine (KYN) pathway has been shown to be altered in several diseases which compromise the central nervous system (CNS) including infectious diseases such as bacterial meningitis (BM). The aim of this study was to assess single nucleotide polymorphisms (SNPs) in four genes of KYN pathway in patients with meningitis and their correlation with markers of immune response in BM. METHODS: One hundred and one individuals were enrolled in this study to investigate SNPs in the following genes: indoleamine-2,3-dioxygenase (IDO1 gene), kynureninase (KYNU gene), kynurenine aminotransferase I (CCBL1 gene), and kynurenine aminotransferase II (AADAT gene). SNP analyses were performed by primer-introduced restriction analysis-PCR (PIRA-PCR) followed by RFLP. Cytokines were measured using multiplex bead assay while immunoglobulins (IG) by immunodiffusion plates and NF-kappaB and c-Jun by dot blot assay. RESULTS: The variant allele of SNP AADAT+401C/T showed prevalent frequency in patients with BM. A significant decrease (p < 0.05) in TNF-α, IL-1ß, IL-6, MIP-1αCCL3 and MIP-1ß/CCL4 levels was observed in BM patients homozygous (TT) to the SNP AADAT+401C/T. Furthermore, a significant (p < 0.05) decrease in cell count was observed in cerebrospinal fluid (CSF) from patients with TT genotype. In addition, an increase in the IgG level in adults (p < 0.05) was observed. The variant allele for KYNU+715G/A was found with low frequency in the groups, and the SNPs in IDO1+434T/G, KYNU+693G/A, CCBL1+164T/C, and AADAT+650C/T had no frequency in this population. CONCLUSIONS: This study is the first report of an association of SNP AADAT+401C/T with the host immune response to BM, suggesting that this SNP may affect the host ability in recruitment of leukocytes to the infection site. This finding may contribute to identifying potential targets for pharmacological intervention as adjuvant therapy for BM.
Assuntos
Meningites Bacterianas/enzimologia , Meningites Bacterianas/imunologia , Polimorfismo de Nucleotídeo Único , Transaminases/genética , Adolescente , Adulto , Alelos , Sequência de Bases , Estudos de Casos e Controles , Quimiocinas/líquido cefalorraquidiano , Citocinas/líquido cefalorraquidiano , Primers do DNA/genética , Feminino , Frequência do Gene , Humanos , Hidrolases/genética , Indolamina-Pirrol 2,3,-Dioxigenase/genética , Masculino , Meningites Bacterianas/líquido cefalorraquidiano , Meningites Bacterianas/genética , Pessoa de Meia-Idade , Adulto JovemRESUMO
In vitro and in animal models, APE1, OGG1, and PARP-1 have been proposed as being involved with inflammatory response. In this work, we have investigated if the SNPs APE1 Asn148Glu, OGG1 Ser326Cys, and PARP-1 Val762Ala are associated to meningitis. The patient genotypes were investigated by PIRA-PCR or PCR-RFLP. DNA damages were detected in genomic DNA by Fpg treatment. IgG and IgA were measured from plasma and the cytokines and chemokines were measured from cerebrospinal fluid samples using Bio-Plex assays. A higher frequency (P<0.05) of APE1 Glu allele in bacterial meningitis (BM) and aseptic meningitis (AM) patients was observed. The genotypes Asn/Asn in control group and Asn/Glu in BM group was also higher. For the SNP OGG1 Ser326Cys, the genotype Cys/Cys was more frequent (P<0.05) in BM group. The frequency of PARP-1 Val/Val genotype was higher in control group (P<0.05). The occurrence of combined SNPs is significantly higher in BM patients, indicating that these SNPs may be associated to the disease. Increasing in sensitive sites to Fpg was observed in carriers of APE1 Glu allele or OGG1 Cys allele, suggesting that SNPs affect DNA repair activity. Alterations in IgG production were observed in the presence of SNPs APE1 Asn148Glu, OGG1 Ser326Cys or PARP-1 Val762Ala. Moreover, reduction in the levels of IL-6, IL-1Ra, MCP-1/CCL2 and IL-8/CXCL8 was observed in the presence of APE1 Glu allele in BM patients. In conclusion, we obtained indications of an effect of SNPs in DNA repair genes on the regulation of immune response in meningitis.