| 41. |
- Lill, Christina M., et al.
(författare)
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The role of TREM2 R47H as a risk factor for Alzheimer's disease, frontotemporal lobar degeneration, amyotrophic lateral sclerosis, and Parkinson's disease
- 2015
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Ingår i: Alzheimer's & Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 11:12, s. 1407-1416
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Tidskriftsartikel (refereegranskat)abstract
- A rare variant in TREM2 (p.R47H, rs75932628) was recently reported to increase the risk of Alzheimer's disease (AD) and, subsequently, other neurodegenerative diseases, i.e. frontotemporal lobar degeneration (FTLD), amyotrophic lateral sclerosis (ALS), and Parkinson's disease (PD). Here we comprehensively assessed TREM2 rs75932628 for association with these diseases in a total of 19,940 previously untyped subjects of European descent. These data were combined with those from 28 published data sets by meta-analysis. Furthermore, we tested whether rs75932628 shows association with amyloid beta (Ab42) and total-tau protein levels in the cerebrospinal fluid (CSF) of 828 individuals with AD or mild cognitive impairment. Our data show that rs75932628 is highly significantly associated with the risk of AD across 24,086 AD cases and 148,993 controls of European descent (odds ratio or OR = 2.71, P = 4.67 x 10(-25)). No consistent evidence for association was found between this marker and the risk of FTLD (OR = 2.24, P = .0113 across 2673 cases/9283 controls), PD (OR 5 1.36, P = .0767 across 8311 cases/79,938 controls) and ALS (OR 5 1.41, P = .198 across 5544 cases/7072 controls). Furthermore, carriers of the rs75932628 risk allele showed significantly increased levels of CSF-total-tau (P = .0110) but not Ab42 suggesting that TREM2's role in AD may involve tau dysfunction. (C) 2015 The Alzheimer's Association.
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| 42. |
- Lindgren, Hanna, et al.
(författare)
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L-DOPA-induced dopamine efflux in the striatum and the substantia nigra in a rat model of Parkinson's disease: temporal and quantitative relationship to the expression of dyskinesia.
- 2010
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Ingår i: Journal of neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 112:6, s. 1465-76
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Tidskriftsartikel (refereegranskat)abstract
- Abstract L-DOPA-induced dyskinesia in Parkinson's Disease (PD) is associated with large increases in brain dopamine (DA) levels following drug dosing, but the precise significance of this phenomenon is not understood. Here we compare DA efflux and metabolism in the striatum and the substantia nigra (SN) in dyskinetic and non-dyskinetic animals following a standard dose of L-DOPA. Rats with 6-OHDA lesions were treated chronically with L-DOPA, monitored on the abnormal involuntary movements (AIMs) scale, and then subjected to intracerebral microdialysis under freely-moving conditions. Following s.c. L-DOPA injection, peak extracellular DA levels in both striatum and SN were twice as large in dyskinetic animals compared to non-dyskinetic rats. This effect was not attributable to differences in DOPA levels or DA metabolism. The larger DA efflux in dyskinetic animals was blunted by 5-HT1A/5-HT1B receptor agonists and TTX infusion, reflecting release from serotonin neurons. Striatal levels of serotonin and its main metabolite, 5-hydroxyindolacetic acid were indeed elevated in dyskinetic animals compared to non-dyskinetic rats, indicating a larger serotonergic innervation density in the former group. High DA release was, however, not sufficient to explain dyskinesia. The AIMs output per unit concentration of striatal extracellular DA was indeed much larger in dyskinetic animals compared to non-dyskinetic cases at most time points examined. The present results indicate that both a high DA release post L-DOPA administration and an increased responsiveness to DA must coexist for a full expression of dyskinesia.
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| 43. |
- Niazi Shahabi, Haydeh, 1966, et al.
(författare)
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An investigation of dopaminergic metabolites in the striatum and in the substantia nigra in vivo utilising radiolabelled L-DOPA and high performance liquid chromatography: a new approach in the search for transmitter metabolites.
- 2003
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Ingår i: Neuroscience. - 0306-4522. ; 120:2, s. 425-33
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Tidskriftsartikel (refereegranskat)abstract
- Although the major routes of dopamine metabolism seem to be established, at least in terminal regions such as the striatum, it is important to search for previously unknown metabolites and to investigate the relevance of previously suggested minor alternative pathways. An urgent issue is to verify and quantify the transformation of dopamine to putative toxic species, another is to further explore metabolism of dopamine located in cell bodies/dendrites, e.g. in the substantia nigra. We have developed a new method in order to widen the search for alternative metabolites of dopamine. The method is based on systemic injection of tritiated L-DOPA to rats in vivo. Brain tissue was homogenised and centrifuged and the resulting supernatant fractioned following passage through a liquid chromatography system. The radioactivity of each fraction was measured using a scintillation system. By identifying fractions containing major catecholamines and metabolites, according to a standard solution, novel metabolites can be searched for in the remaining fractions. It was possible to obtain sufficient radioactivity in separate fractions of supernatant of homogenised tissue, even from such a small brain nucleus as substantia nigra. Radioactivity was obtained in those fractions that contained the major catecholamines and their metabolites, as well as in other fractions where it may represent previously unknown metabolites of L-DOPA/dopamine. The method was used to evaluate the possibility that cytochrome P450 2E1 is involved in the metabolism of dopamine in the substantia nigra. Significant changes in the radioactivity pattern were induced by inhibition of the enzyme but conclusions about whether cytochrome P450 2E1 is involved in the metabolism of dopamine or not requires further studies. The method can be used to study the metabolism of dopamine and can be extended, by using other radiolabelled precursors, also to evaluate metabolism of other transmitters, e.g. serotonin.
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| 44. |
- Näslund, Jakob, et al.
(författare)
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Differences in anxiety-like behavior within a batch of wistar rats are associated with differences in serotonergic transmission, enhanced by acute sri administration, and abolished by serotonin depletion
- 2015
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Ingår i: International Journal of Neuropsychopharmacology. - : Oxford University Press (OUP). - 1461-1457 .- 1469-5111. ; 18:8, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Background: The anxiety-reducing effect of long-term administration of serotonin reuptake inhibitors is usually seen only in subjects with anxiety disorders, and such patients are also abnormally inclined to experience a paradoxical anxietyenhancing effect of acute serotonin reuptake inhibition. These unique responses to serotonin reuptake inhibitors in anxietyprone subjects suggest, as do genetic association studies, that inter-individual differences in anxiety may be associated with differences in serotonergic transmission. Methods: The one-third of the animals within a batch of Wistar rats most inclined to spend time on open arms in the elevated plus maze were compared with the one-third most inclined to avoid them with respect to indices of brain serotonergic transmission and how their behavior was influenced by serotonin-modulating drugs. Results: "Anxious" rats displayed higher expression of the tryptophan hydroxylase-2 gene and higher levels of the tryptophan hydroxylase-2 protein in raphe and also higher levels of serotonin in amygdala. Supporting these differences to be important for the behavioral differences, serotonin depletion obtained by the tryptophan hydroxylase-2 inhibitor p-chlorophenylalanine eliminated them by reducing anxiety in "anxious" but not "non-anxious" rats. Acute administration of a serotonin reuptake inhibitor, paroxetine, exerted an anxiety-enhancing effect in "anxious" but not "non-anxious" rats, which was eliminated by long-term pretreatment with another serotonin reuptake inhibitor, escitalopram. Conclusions: Differences in an anxiogenic impact of serotonin, which is enhanced by acute serotonin reuptake inhibitor administration, may contribute to differences in anxiety-like behavior amongst Wistar rats..
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| 45. |
- Patil, Jaspal, et al.
(författare)
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Sustained Effects of Neonatal Systemic Lipopolysaccharide on IL-1 beta and Nrf2 in Adult Rat Substantia Nigra Are Partly Normalized by a Spirulina-Enriched Diet
- 2016
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Ingår i: Neuroimmunomodulation. - : S. Karger AG. - 1021-7401 .- 1423-0216. ; 23:4, s. 250-259
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Tidskriftsartikel (refereegranskat)abstract
- Background/Aim: Neonatal infection can sensitize the adult substantia nigra (SN) to secondary insults, causing a decrease in antioxidant capacity which may lead to Parkinson's disease in adults. We studied the prolonged effect of systemic infection by (i.p.) administration of lipopolysaccharide (LPS) on interleukin (IL)-1 beta, the antioxidant regulator nuclear factor-erythroid 2-related factor 2 (Nrf2), and the peroxi-some proliferator-activated receptor gamma coactivator (PGC)-1 alpha in rat SN. Method and Results: Five-day-old rat pups were treated with LPS (i. p. 2 mg/kg). After 65 days, the mRNA level of IL-1 beta was significantly increased, in parallel with a decrease in that of the rate-limiting enzyme in glutathione synthesis, the gamma-glutamylcysteine ligase catalytic subunit (gamma GCLc), Nrf2, and brain-derived neurotrophic factor (BDNF). Protein levels of gamma GCLc and Nrf2 were decreased while IL-1 beta protein was significantly increased. These LPS-induced long-term changes correlated with a decrease in phosphorylated (active) AKT (pAKT) and phosphorylated (inactive) GSK-3 beta (pGSK-3 beta). In another set of experiments, a 0.1% Spirulina-containing diet was given to lactating mothers 24 h before the LPS treatment of the pups. The Spirulina-supplemented diet decreased IL-1 beta protein expression in SN and elevated the mRNA level of gamma GCLc, Nrf2 protein, PGC-1 alpha protein, and pAKT. Conclusion: Early-life infection can negatively affect Nrf2, pAKT, and pGSK-3 beta for a long time in SN. A diet en-riched with antioxidant and anti-inflammatory phytochemicals can partly restore some, but not all, of the effects on the antioxidant defense, possibly via normalizing effects on pAKT. (C) 2016 S. Karger AG, Basel
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| 46. |
- Pihlstrom, L., et al.
(författare)
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Fine mapping and resequencing of the PARK16 locus in Parkinson's disease
- 2015
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Ingår i: Journal of Human Genetics. - : Springer Science and Business Media LLC. - 1434-5161 .- 1435-232X. ; 60:7, s. 357-362
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Tidskriftsartikel (refereegranskat)abstract
- The PARK16 locus, spanning five genes on chromosome 1, was among the first genetic regions to show genome-wide association in Parkinson's disease (PD). Subsequent investigations have found variability in PARK16 top-hits and association patterns across populations, and the implicated genes and mechanisms are currently unclear. In the present study, we aimed to explore the contribution of PARK16 variability to PD risk in a Scandinavian population. We genotyped 17 single-nucleotide polymorphisms in a case-control sample set of 2570 individuals from Norway and Sweden to fine map the locus. Targeted resequencing of the full coding regions of SLC45A3, NUCKS1, RAB7L1, SLC41A1 and PM20D1 was performed in DNA pools from a subset of 387 patient samples. We find evidence for an association with PD for rs1775143 as well as a haplotype located around the 5' region of RAB7L1, implicating variants which are not in high linkage disequilibrium with the strongest signal from a recent large meta-analysis in Caucasians. We also provide suggestive support for epistasis between RAB7L1 and LRRK2 as previously hypothesized by others. Comparing our results with previous work, allelic heterogeneity at PARK16 appears likely, and further studies are warranted to disentangle the complex patterns of association and pinpoint the functionally relevant variants.
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| 47. |
- Pihlstrom, L., et al.
(författare)
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Supportive evidence for 11 loci from genome-wide association studies in Parkinson's disease
- 2013
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 34:6
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Tidskriftsartikel (refereegranskat)abstract
- enome-wide association studies have identified a number of susceptibility loci in sporadic Parkinson's disease (PD). Recent larger studies and meta-analyses have greatly expanded the list of proposed association signals. We performed a case-control replication study in a Scandinavian population, analyzing samples from 1345 unrelated PD patients and 1225 control subjects collected by collaborating centers in Norway and Sweden. Single-nucleotide polymorphisms representing 18 loci previously reported at genome-wide significance levels were genotyped, as well as 4 near-significant, suggestive, loci. We replicated 11 association signals at p < 0.05 (SNCA, STK39, MAPT, GPNMB, CCDC62/HIP1R, SYT11, GAK, STX1B, MCCC1/LAMP3, ACMSD, and FGF20). The more recently nominated susceptibility loci were well represented among our positive findings, including 3 which have not previously been validated in independent studies. Conversely, some of the more well-established loci failed to replicate. While future meta-analyses should corroborate disease associations further on the level of common markers, efforts to pinpoint functional variants and understand the biological implications of each risk locus in PD are also warranted.
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| 48. |
- Ran, Caroline, et al.
(författare)
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Glucocerebrosidase variant T369M is not a risk factor for Parkinson's disease in Sweden.
- 2022
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Ingår i: Neuroscience Letters. - : Elsevier. - 0304-3940 .- 1872-7972. ; 784
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Genetic variants in the Beta-glucocerebrosidase gene (GBA1) is a known risk factor for Parkinson's disease. The GBA1 mutations L444P, N370S and many other have been shown to associate with the disease in populations with diverse background. Some GBA1 polymorphisms have a less pronounced effect, and their pathogenicity has been debated. We have previously found associations with L444P, N370S and E326K and Parkinson's disease in Sweden.METHOD: In this study we used pyrosequencing to genotype the T369M variant in a large Swedish cohort consisting of 1,131 patients with idiopathic Parkinson's disease, and 1,594 control subjects to evaluate the possibility of this variant conferring an increased risk for Parkinson's disease.RESULTS: The minor allele frequency was 2.15% in patients and 1.76% in controls. Statistical analysis showed that there was no significant difference in allele frequency between patients and control subjects, p-value 0.37, Odds Ratio 1.23 with a 95% confidence interval of 0.82-1.83.CONCLUSION: Our results suggest that T369M is not a risk factor for Parkinson's disease in the Swedish population.
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| 49. |
- Ran, Caroline, et al.
(författare)
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No association between rs7077361 in ITGA8 and Parkinson’s disease in Sweden
- 2016
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Ingår i: Open Neurology Journal. - 1874-205X. ; 10, s. 25-29
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Tidskriftsartikel (refereegranskat)abstract
- Background: Integrin alpha 8 (ITGA8) encodes the alpha 8 subunit of the integrin alpha8beta1 protein and has recently been suggested as a new candidate gene for Parkinson’s disease, an age related neurodegenerative disease with unknown etiology. ITGA8 is a transmembrane protein involved in several cellular processes, such as cell adhesion, migration and cytoskeletal rearrangement. Objective: Screen a Swedish case control material for rs7077361, a genetic variant in ITGA8, in order to investigate its possible implication in Parkinson’s disease in Sweden. Method: Rs7077361 was genotyped using TaqMan quantitative Real-time PCR and tested for association using appropriate statistical methods. Results: We have screened 502 Swedish Parkinson patients and 599 healthy control individuals for rs7077361 in ITGA8. This genetic variant was in Hardy Weinberg equilibrium in the Swedish population. Allele and genotype frequencies were highly similar between the patients and controls and statistical testing showed that this genetic maker did not associate with Parkinson’s disease (p=0.67). Conclusion: Our results do not support the hypothesis of ITGA8 as a candidate gene for Parkinson’s disease in Sweden. © Ran et al.
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| 50. |
- Ran, C., et al.
(författare)
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Strong association between glucocerebrosidase mutations and Parkinson's disease in Sweden
- 2016
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 45
-
Tidskriftsartikel (refereegranskat)abstract
- Several genetic studies have demonstrated an association between mutations in glucocerebrosidase (GBA), originally implicated in Gaucher's disease, and an increased risk of Parkinson's disease (PD). We have investigated the possible involvement of genetic GBA variations in PD in the Swedish population. Three GBA variants, E326K, N370S, and L444P were screened in the largest Swedish Parkinson cohort reported to date; 1625 cases and 2025 control individuals. We found a significant association with high effect size of the rare variant L444P with PD (odds ratio 8.17; 95% confidence interval: 2.51-26.23; p-value = 0.0020) and a significant association of the common variant E326K (odds ratio 1.60; 95% confidence interval: 1.16-2.22; p-value = 0.026). The rare variant N370S showed a trend for association. Most L444P carriers (68%) were found to reside in northern Sweden, which is consistent with a higher prevalence of Gaucher's disease in this part of the country. Our findings support the role of GBA mutations as risk factors for PD and point to lysosomal dysfunction as a mechanism contributing to PD etiology. (C) 2016 The Author(s). Published by Elsevier Inc.
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