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

Alzheimer's 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 Parkinson's 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

Susceptibility genes in conformational diseases

Conformational diseases are characterized by protein misfolding and aggregation in the affected tissue. The aim of this thesis was to find genetic support for mechanisms in common for three prevalent confor-mational diseases: Alzheimer’s disease (AD), Parkinson’s disease (PD) and cataract. The influence of genetic variability in candidate genes hypothesized to be involved in protein aggregation was investigated for association with risk of the sporadic forms of AD, PD and cataract. Furthermore, analysis of association with age at onset (AAO) of disease, and, for AD, association with mini-mental state examination (MMSE) scores and levels of the cerebrospinal fluid (CSF) biomarkers: Aβ42 (the 42 amino acid form of amyloid β), T-tau (total tau, i.e. all isoforms of tau) and P-tau181 (hyper-phosphorylated tau protein as measured by phosphorylation on amino acid 181) was carried out. The kinesin protein is important for maintaining cell shape and function, especially in elongated cells such as neurons and lens cells. Previous molecular and genetic studies support impaired kinesin-mediated transport as a potential contributor in AD, PD and cataract. We analysed the contribution of variation in the kinesin light chain 1 gene (KLC1) encoding the kinesin light chain protein 1 protein (KLC1), initially by using a single nucleotide polymorphism (SNP) approach (paper I and II) and later in a haplotype study (paper III). Altogether, with the possible exception for cataract, the results of these papers do not support genetic influence of KLC1 on risk of disease. Oxidative stress is a contributing factor to aging and degenerative diseases. The proteins Nrf2 (nuclear factor (erythroid-derived 2)-like 2) and Keap1 (Kelch-like ECH-associated protein 1), constitute the two main regulators of the induced cellular oxidative stress defense called the phase II response. In paper IV and V we investigated their respective genes NFE2L2 (Nuclear factor (erythroid-derived 2)-like 2) and KEAP1 (Kelch-like ECH-associated protein 1) as possible susceptibility genes in AD, PD and cataract. We found that variation in one NFE2L2 haplotype window, which is in LD with functional promoter polymorphisms in the same gene, was associated with risk of PD in two independent European case-control materials (paper IV). In AD and cataract, variation in the same haplotype window was associated with AAO of the diseases (paper V). No association of KEAP1 with any of the studied diseases was found. The major finding of this thesis was the identification of NFE2L2 as a potential susceptibility gene in PD adding genetic support to current indications that Nrf2 may have an important function in the cellular defense against PD

Association of NFE2L2 and KEAP1 haplotypes with amyotrophic lateral sclerosis.

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

Association of the RAGE G82S polymorphism with Alzheimer\u27s disease

The receptor for advanced glycation end-products (RAGE) has been implicated in several pathophysiological processes relevant to Alzheimer\u27s disease (AD), including transport and synaptotoxicity of AD-associated amyloid beta (A beta) peptides. A recent Chinese study (Li et al. in J Neural Transm 117:97-104, 2010) suggested an association between the 82S allele of the functional single nucleotide polymorphism (SNP) G82S (rs2070600) in the RAGE-encoding gene AGER and risk of AD. The present study aimed to investigate associations between AGER, AD diagnosis, cognitive scores and cerebrospinal fluid AD biomarkers in a European cohort of 316 neurochemically verified AD cases and 579 controls. Aside from G82S, three additional tag SNPs were analyzed to cover the common genetic variation in AGER. The 82S allele was associated with increased risk of AD (P (c) = 0.04, OR = 2.0, 95% CI 1.2-3.4). There was no genetic interaction between AGER 82S and APOE epsilon 4 in producing increased risk of AD (P = 0.4), and none of the AGER SNPs showed association with A beta(42), T-tau, P-tau(181) or mini-mental state examination scores. The data speak for a weak, but significant effect of AGER on risk of AD

Genetic associations of Nrf2-encoding NFE2L2 variants with Parkinson s disease a multicenter study Genetic associations of Nrf2-encoding NFE2L2 variants with Parkinson s disease a multicenter study

Abstract Background: The transcription factor Nrf2, encoded by the NFE2L2 gene, is an important regulator of the cellular protection against oxidative stress. Parkinson? s disease is a neurodegenerative disease highly associated with oxidative stress. In a previously published study, we reported associations of NFE2L2 haplotypes with risk and age at onset of idiopathic Parkinson? s disease in a Swedish discovery material and a Polish replication material. Here, we have extended the replication study and performed meta-analyses including the Polish material and four new independent European patient-control materials. Furthermore, all SNPs included in the haplotype windows were investigated individually for associations with Parkinson? s disease in meta-analyses including all six materials

Association of Nrf2-encoding <it>NFE2L2 </it>haplotypes with Parkinson's disease

Abstract Background Oxidative stress is heavily implicated in the pathogenic process of Parkinson's 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 Parkinson's disease. Methods The 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. Results We 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. Conclusion These data suggest that variation in NFE2L2 modifies the Parkinson's disease process and provide another link between oxidative stress and neurodegeneration.</p

Association of Nrf2-encoding NFE2L2 haplotypes with Parkinson\u27s disease.

BACKGROUND: Oxidative stress is heavily implicated in the pathogenic process of Parkinson\u27s 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 Parkinson\u27s disease. METHODS: The 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. RESULTS: We 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 x 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. CONCLUSION: These data suggest that variation in NFE2L2 modifies the Parkinson\u27s disease process and provide another link between oxidative stress and neurodegeneration

A novel ARC gene polymorphism is associated with reduced risk of Alzheimer's disease

Alzheimer's disease (AD) is the most common neurodegenerative disease, and is clinically characterized by cognitive disturbances and the accumulation of the amyloid beta (A beta) peptides in plaques in the brain. Recent studies have shown the links between AD and the immediate-early gene Arc (activity-regulated cytoskeleton-associated protein), involved in synaptic plasticity and memory consolidation. For example, AD mouse models show a decreased expression of Arc mRNA in the brain. In additional, acute A beta application to brain slices leads to a widespread ARC protein diffusion, unlike the normal defined localization to synapses. In this study, we investigated genetic variation in human ARC and the risk of developing AD. To this end, we genotyped 713 subjects diagnosed with AD and 841 controls without dementia. ARC was sequenced in a group of healthy individuals, and seven previously known SNPs and three novel SNPs were identified. Two of the newly found SNPs were intronic and one, +2852(G/A), was located in the 3'UTR. Three tag SNPs were selected, including the novel SNP +2852(G/A), to relate to risk of AD, Mini Mental State Examination (MMSE) scores and cerebrospinal fluid (CSF) biomarker levels of total tau (T-tau), hyperphosphorylated tau181 (P-tau(181)) and A beta(1-42). The AA genotype of the newly found 3'-UTR SNP +2852(A/G), was associated with a decreased risk of AD (p (c) = 0.005; OR = 0.74; 95 % CI: 0.61-0.89). No associations of single SNPs or haplotypes with MMSE score or CSF biomarkers were found. Here we report a novel ARC SNP associated with a reduced risk of developing AD. To our knowledge, this is the first study associating a gene variant of ARC with any disease. The location of the SNP within the 3'UTR indicates that dendritic targeting of ARC mRNA could be involved in the molecular mechanisms underlying this protective function. However, further investigation of the importance of this SNP for ARC function, ARC processing and the pathology of AD is needed