PCR/RFLP-based cost-effective identification of SOD2 signal (leader) sequence polymorphism (Ala–9Val) using NgoM IV: a detailed methodological approach

Genetic Polymorphism of Manganese Superoxide Dismutase in Behçet's Disease

Objectives

This study aims to investigate the genetic association between single nucleotide mutation in mitochondrial manganese superoxide dismutase and a Behçet's disease (BD) population by using molecular techniques.

Patients and methods

Ninety-three BD patients (45 males, 48 females; mean age 33.15±8.99 years; range 17 to 65 years) and 125 controls (58 males, 67 females; mean age 28.33±7.31 years; range 18 to 62 years) were genotyped by polymerase chain reaction-restriction fragment length polymorphism method. The genotypic distributions in BD patients and controls were consistent with the Hardy-Weinberg equilibrium.

Results

Significant differences were observed between BD patients and controls in terms of genotypic distribution. Frequencies of alanine (Ala)/Ala, Ala/valine (Val), and Val/Val were 14.0% (n=13), 45.2% (n=42), and 40.9% (n=38) in BD patients and 21.6% (n=27), 53.6% (n=67), and 24.8% (n=31) in controls, respectively (p=0.033).

Conclusion

The Val/Val genotype of the manganese superoxide dismutase gene is associated with the physiopathology of BD in a group of Turkish patients.

Involvement of NAD(P)H:quinone oxidoreductase 1 and superoxide dismutase polymorphisms in ulcerative colitis

Inflammatory bowel disease is a multifactorial disease. Oxidative stress has been thought to be one of etiologic factor for inflammatory bowel disease. The genes superoxide dismutase (SOD2) and NAD(P)H:quinone oxidoreductase 1 (NQO1) are involved in inflammation and oxidative stress. The purpose of the present case-control study with 134 patients with ulcerative colitis (UC) and 125 healthy controls was to determine whether polymorphisms of these genes, the NQO1 C609T and the SOD2 Ala-9Val, are associated with the risk of UC and influence the clinical characteristics. These polymorphisms were examined by polymerase chain reaction-restriction fragment length polymorphisms and direct sequencing. In patients showing steroid resistance, the number with the NQO1 T/T genotype was significantly higher than other genotypes (odds ratio 9.45, 95% confidence interval 2.46-41.6, p = 0.002). In the patients whose onset of UC was age 20 years or younger, more patients had SOD2 T/T genotype than the other genotypes (odds ratio 6.46, 95% confidence interval 0.82-51.0). No association between these polymorphisms and UC risk was apparent. The NQO1 C609T polymorphism may influence steroid resistance of UC patients, while the SOD2 Ala-9Val polymorphism may influence age of onset of UC. Oxidative stress may influence the clinical features of UC.

Manganese and extracellular superoxide dismutase polymorphisms and risk for asbestosis

Manganese and extracellular superoxide dismutases (SOD2 and SOD3) are part of the enzymatic defence against reactive oxygen species, which are involved in the pathogenesis of asbestosis. This study investigates whether SOD2Ala − 9Val and SOD3 Arg213Gly genetic polymorphisms represent risk factors for asbestosis in workers exposed to asbestos. The study included 262 cases with asbestosis and 265 controls with no asbestos-related disease. Cumulative asbestos exposure was calculated for each subject. A real-time PCR assay was introduced for genotyping. Logistic regression analysis was used to assess asbestosis risk. Asbestosis was associated with the homozygous SOD2 − 9Ala/Ala genotype (OR = 1.50, 95% CI 1.01–2.24), whereas the association for the SOD3 Arg/Gly genotype was not significant (OR = 1.63, 95% CI 0.62–4.27). The finding that the SOD2 − 9Ala/Ala genotype increases the risk for asbestosis indicates that, in addition to asbestos exposure, genetic factors may also have a significant influence on the development of asbestosis.

Lack of Association Between Pseudoexfoliation Syndrome and Manganese Superoxide Dismutase Polymorphism

PURPOSE

The aim of this clinical study was to investigate the possible association between manganese superoxide dismutase (Mn-SOD) enzyme polymorphism in the mitochondrial targeting sequence and pseudoexfoliation syndrome.

METHODS

Ala (GTT) or Val (GCT) polymorphism in the signal peptide of Mn-SOD gene was evaluated using a primer pair to amplify a 107-bp fragment followed by digestion with restriction enzyme NgoM IV.

RESULTS

The frequencies of Ala-9 and Val-9 variants and genotypes of Mn-SOD were similar in the controls and pseudoexfoliation syndrome patients.

CONCLUSIONS

These results suggest no major modifying role for the Mn-SOD gene polymorphism in patients with pseudoexfoliation syndrome.

Polymorphism in glutathione-S-transferases: a risk factor in alcoholic liver cirrhosis

In a case-control study, association of polymorphism in glutathione-S-transferases (GSTM1, GSTT1, GSTP1), involved in detoxification of reactive oxygen species (ROS), was studied with alcoholic liver cirrhosis. The study included 175 alcoholic cirrhotic patients (ACPs), 140 non-alcoholic cirrhotic patients (NACPs), visiting Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGI), Lucknow, India, 255 non-alcoholic controls and 140 alcoholic controls. The data showed an increase in risk to alcoholic cirrhosis in ACPs with GSTM1 (null) genotype when compared with non-alcoholic controls (OR: 1.7; 95% CI: 1.15-2.56) or alcoholic controls (OR: 1.7; 95% CI: 1.07-2.73). Significant increase in risk was also observed in ACPs with variant genotype of GSTP1 when compared with non-alcoholic controls (OR: 1.65; 95% CI: 1.12-2.43). A much higher risk to alcoholic liver cirrhosis was observed in patients carrying combination of null genotypes of GSTM1 and GSTT1 (OR: 2.8; 95% CI: 1.3-6.06) or variant genotype of GSTP1 and null genotype of GSTM1 (OR: 2.8; 95% CI: 1.58-4.90) or GSTT1 (OR: 2.16; 95% CI: 1.08-4.28). Likewise, greater risk for alcoholic cirrhosis was observed in patients carrying combination of GSTM1, GSTT1 (null) and variant genotype of GSTP1 (OR: 5.8; 95% CI: 2.17-15.80). Our data further showed that interaction of GSTs with variant genotype of manganese superoxide dismutase (MnSOD), which detoxifies free radicals, or cytochrome P450 2E1, which generates free radicals, resulted in several fold increase in risk to alcoholic liver cirrhosis in ACPs when compared with non-alcoholic controls thus demonstrating the role of gene-gene interactions in modulating the risk to alcoholic liver cirrhosis.

Age-dependent dichotomous effect of superoxide dismutase Ala16Val polymorphism on oxidized LDL levels

We investigated the association between superoxide dismutase (SOD) Ala16Val polymorphism and the levels of oxidized LDL lipoprotein-C (ox-LDL-C) in two age-different Greek cohorts. Four hundred fifteen middle-aged (n=147 females: 43.2+/-13 years, n=268 males: 43.3+/-14 years) Caucasian Greek subjects consisted the middle aged cohort. One hundred seventy five elderly (n=88 females: 79.9+/-4 years; n=87 males: 80.6+/-4 years) were selected from the elderly cohort. Genotype data were obtained for all of them. Multiple linear regression analysis, stratified by gender and adjusted for age, smoking habits and body mass index as covariates, showed higher ox-LDL-C levels for the middle aged men with the Val/Val genotype, compared to the other allele (Ala/Ala and Ala/Val) carriers (65.9+/-25.7 vs. 55.7+/-20.5 mg/dl; standardized beta coefficient=0.192, P=0.012). On the contrary, elderly women with the Val/Val genotype occurred with lower ox-LDL-C levels compared to the Ala/Ala or Ala/Val genotype (74.2+/-22.1 vs. 86.5+/-26.6 mg/dl; standardized beta coefficient= -0.269, P=0.015). The same trend was also recorded in elderly men, however without reaching statistical significance (standardized beta coefficient= -0.187, P=0.077). Moreover, elderly men and women with the Ala/Ala or Ala/Val genotype presented higher triglycerides levels compared to Val/Val (women: 145.2+/-68.7 vs. 114.3+/- 34.3 mg/dl, P= 0.027; men: 147.8+/-72.4 vs. 103.7 +/-38.0 mg/dl, P=0.002). Additionally, middle aged men with the Val/Val genotype had higher HDL-C levels compared to the Ala allele carriers. The results suggest that SOD Ala16Val polymorphism is an age-dependent modulator of ox-LDL-C levels in middle-aged men and elderly women.

Polymorphism in environment responsive genes and association with Parkinson disease

Attempts were made in the present case-control study to investigate the association of polymorphism in the genes encoding proteins involved in toxication-detoxication and dopaminergic pathways and susceptibility to Parkinson's disease (PD). Seventy patients suffering from PD and one hundred healthy controls belonging to the same geographical location and same ethnicity were included in the study. PCR-RFLP and allele-specific PCR-based methodology were used to identify the genotypes. Multivariate logistic regression analysis revealed that heterozygous genotypes of cytochrome P4502D6*4(CYP2D6*4), CYP2E1*5B (RsaI) polymorphism and homozygous mutant genotypes of CYP2E1*6 (Dra1) were found to be overrepresented in PD cases when compared to the controls. Risk was also found to be increased in patients carrying glutathione S-transferase T1 (GSTT1) null or homozygous variant genotypes of GSTP1. Significant association was observed for monoamine oxidase-B(MAO-B) variant allele G and PD, whereas no difference in genotype and allele frequencies was observed for manganese-superoxide dismutase (MnSOD), dopamine receptor-D2(DRD2), and dopamine transporter (DAT) genes between controls and PD cases. Genotype combinations characterized by the presence of two variant genotypes on their corresponding loci revealed that four combinations of GSTT1 null and MnSOD(-9Val) or GST null and MAOB-G or CYP2E1*5B and MAO-B-AG or CYP2E1*5B and DRD2 (Taq1A-het) genotypes in the patients exhibited severalfold higher and significant association with risk to PD. Our data suggest that polymorphism in the genes involved in detoxification and dopamine regulation may modulate the susceptibility to PD and could be important risk factors in the pathogenesis of PD.

The Ala-9Val polymorphism in the mitochondrial targeting sequence (MTS) of the manganese superoxide dismutase gene is not associated with juvenile-onset asthma

BACKGROUND

We aimed to investigate the possible association between Mn-SOD polymorphism in the mitochondrial targeting sequence and asthma.

METHODS

Alanine or valine polymorphism in the signal peptide of Mn-SOD gene was evaluated using a primer pair to amplify a 107-bp fragment followed by digestion with NgoM IV.

RESULTS

No significant difference in genotype frequencies was found between patients and controls.

CONCLUSION

These results suggest no major modifying role for the Mn-SOD gene polymorphism in patients with asthma.

Association between Ala-9Val polymorphism of Mn-SOD gene and schizophrenia

Reactive oxygen species (ROS) have been suggested to play an important role in physiopathology of schizophrenia. The major intracellular antioxidant enzymes, copper-zinc superoxide dismutase in the cytoplasm and manganese superoxide dismutase (Mn-SOD) in the mitochondria, rapidly and specifically reduce superoxide radicals to hydrogen peroxide. Polymorphisms in the genes encoding antioxidant enzymes should therefore result in predisposition to schizophrenia. The present study was performed to assess whether there is a genetic association between a functional polymorphism (Ala-9Val) in the human Mn-SOD gene in schizophrenic patients (n=153) and healthy controls (n=196) using a PCR/RFLP method. Significant differences in the genotypic distribution between schizophrenics and controls were observed. Genotypic distribution with 14 (9.2%) Ala/Ala, 106 (69.3%) Ala/Val and 33 (21.6%) Val/Val subjects in schizophrenia was different from those of controls with 46 (23.5%), 83 (42.3%) and 67 (34.2%), respectively (p<0.0001). When the patients with schizophrenia were divided into the subgroups as disorganized, paranoid and residual, there was a significant difference in genotypic distribution among the subgroups (chi2=11.35, df=4, p=0.023). This association between -9Ala Mn-SOD allele and schizophrenia suggests that -9Ala variant may have a contribution in the physiopathogenesis of schizophrenia. Further investigations are warranted in larger populations with other susceptible genes that might be associated with schizophrenia.