Malin von Otter

Association of Nrf2-encoding NFE2L2 haplotypes with Parkinson's disease

BackgroundOxidative stress is heavily implicated in the pathogenic process of Parkinsons disease. Varying capacity to detoxify radical oxygen species through induction of phase II antioxidant enzymes in substantia nigra may influence disease risk. Here, we hypothesize that variation in NFE2L2 and KEAP1, the genes encoding the two major regulators of the phase II response, may affect the risk of Parkinsons disease.MethodsThe study included a Swedish discovery case-control material (165 cases and 190 controls) and a Polish replication case-control material (192 cases and 192 controls). Eight tag single nucleotide polymorphisms representing the variation in NFE2L2 and three representing the variation in KEAP1 were chosen using HapMap data and were genotyped using TaqMan Allelic Discrimination.ResultsWe identified a protective NFE2L2 haplotype in both of our European case-control materials. Each haplotype allele was associated with five years later age at onset of the disease (p = 0.001) in the Swedish material, and decreased risk of PD (p = 2 × 10-6), with an odds ratio of 0.4 (95% CI 0.3-0.6) for heterozygous and 0.2 (95% CI 0.1-0.4) for homozygous carriers, in the Polish material. The identified haplotype includes a functional promoter haplotype previously associated with high transcriptional activity. Genetic variation in KEAP1 did not show any associations.ConclusionThese data suggest that variation in NFE2L2 modifies the Parkinsons disease process and provide another link between oxidative stress and neurodegeneration.

Nrf2-encoding NFE2L2 haplotypes influence disease progression but not risk in Alzheimer's disease and age-related cataract.

Alzheimers disease (AD) and age-related cataract, disorders characterized by protein aggregation causing late-onset disease, both involve oxidative stress. We hypothesize that common variants of NFE2L2 and KEAP1, the genes encoding the main regulators of the Nrf2 system, an important defence system against oxidative stress, may influence risk of AD and/or age-related cataract. This case-control study combines an AD material (725 cases and 845 controls), and a cataract material (489 cases and 182 controls). Genetic variation in NFE2L2 and KEAP1 was tagged by eight and three tag single nucleotide polymorphisms (SNPs), respectively. Single SNPs and haplotypes were analyzed for associations with disease risk, age parameters, MMSE and AD cerebrospinal fluid biomarkers. NFE2L2 and KEAP1 were not associated with risk of AD or cataract. However, one haplotype allele of NFE2L2 was associated with 2 years earlier age at AD onset (p(c)=0.013) and 4 years earlier age at surgery for posterior subcapsular cataract (p(c)=0.019). Another haplotype of NFE2L2 was associated with 4 years later age at surgery for cortical cataract (p(c)=0.009). Our findings do not support NFE2L2 or KEAP1 as susceptibility genes for AD or cataract. However, common variants of the NFE2L2 gene may affect disease progression, potentially altering clinically recognized disease onset.

Proteomics Profiling of Single Organs from Individual Adult Zebrafish

The model organism zebrafish (Danio rerio) is extensively utilized in studies of developmental biology but is also being investigated in the context of a growing list of human age-related diseases. To facilitate such studies, we here present protein expression patterns of adult zebrafish organs, including blood, brain, fin, heart, intestine, liver, and skeletal muscle. Protein extracts were prepared from the different organs of two zebrafish and analyzed using liquid chromatography coupled to high-resolution tandem mass spectrometry. Zebrafish tissue was digested directly after minimal fractionation and cleaned up (the shotgun approach). Proteins were identified using Mascot software. In total, 1394 proteins were identified of which 644 were nonredundant. Of these, 373 demonstrated an organ-specific expression pattern and 57 had not been shown on protein level before. These data emphasize the need for increased research at the protein level to facilitate the selection of candidate proteins for targeted quantification and to refine systematic genetic network analysis in vertebrate development, biology, and disease.

Association of NFE2L2 and KEAP1 haplotypes with amyotrophic lateral sclerosis

Abstract Amyotrophic lateral sclerosis (ALS) is a degenerative motor neuron syndrome influenced by oxidative stress. The transcription factor Nrf2 and its repressor Keap1 constitute an important defence system in cellular protection against oxidative stress. Here we hypothesize that common genetic variations in the genes NFE2L2 and KEAP1, encoding Nrf2 and Keap1, may influence the risk and phenotype of ALS. Five hundred and twenty-two Swedish patients with sporadic ALS (SALS) and 564 Swedish control subjects were studied. Eight tag SNPs in NFE2L2 and three tag SNPs in KEAP1 were genotyped by allelic discrimination and three functional NFE2L2 promoter SNPs were genotyped by sequencing. One NFE2L2 haplotype (GGGAC) was associated with decreased risk of SALS (OR = 0.62 per allele, p = 0.003) and one haplotype in KEAP1 (CGG) was associated with later SALS onset (+3.4 years per allele, p = 0.015). When stratified by subgroup, one haplotype in NFE2L2, GAGCAGA including three functional promoter SNPs associated with high Nrf2 protein expression, was associated with 4.0 years later disease onset per allele in subgroup ALS (p = 0.008). In conclusion, these results suggest that variations in NFE2L2 and KEAP1, encoding two central proteins in cellular oxidative stress defence, may influence SALS pathogenesis.

Ubiquitin carboxy-terminal hydrolase L1 (UCHL1) S18Y polymorphism in Alzheimer's disease

Alzheimers disease (AD) is characterized by protein aggregates, i.e. senile plaques and neurofibrillary tangles. The ubiquitin-proteasome system has been proposed a role in proteolytic removal of these protein aggregates. Ubiquitin carboxy-terminal hydrolase L1 (UCHL1) is a de-ubiquitinating enzyme with important functions in recycling of ubiquitin. The S18Y polymorphism of the UCHL1 gene confers protection against Parkinsons disease. In this study, the genotype and allele frequencies of the UCHL1 S18Y polymorphism were investigated in 452 AD patients and 234 control subjects, recruited from four memory clinics in Sweden. Using a binary logistic regression model including UCHL1 allele A and APOE ε4 allele positivity, age and sex as covariates with AD diagnosis as dependent variable, an adjusted OR of 0.82 ([95% CI 0.55-1.24], P = 0.35) was obtained for a positive UCHL1 allele A carrier status. The present study thus do not support a protective effect of the UCHL1 S18Y polymorphism against AD.