| 1. |
- Correa, Fernando, et al.
(författare)
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The Nrf2-inducible antioxidant defense in astrocytes can be both up- and down-regulated by activated microglia:Involvement of p38 MAPK.
- 2011
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Ingår i: Glia. - : Wiley. - 1098-1136 .- 0894-1491. ; 59:5, s. 785-99
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Tidskriftsartikel (refereegranskat)abstract
- The effects of microglia-conditioned medium (MCM) on the inducible Nrf2 system in astrocyte-rich cultures were investigated by determination of glutathione (GSH) levels, γglutamylcysteine ligase (γGCL) activity, the protein levels of Nrf2, Keap1, the modulatory subunit of γGCL (γGCL-M) and activated MAP kinases (ERK1/2, JNK and p38). Microglia were either cultured for 24 h in serum-free culture medium to achieve microglia-conditioned medium from non-activated cells (MCM(0) ), used as control condition, or activated with different concentrations (0.1-1,000 ng mL(-1) ) of lipopolysaccharide (LPS) to produce MCM(0.1-1,000) . Acute exposure (24 h) to MCM(100) increased GSH, γGCL activity, the protein levels of γGCL-M, Nrf2, and activated JNK and ERK1/2 in astrocyte-rich cultures. In contrast, treatment with MCM(10) for 24 h decreased components of the Nrf2 system in parallel with activation of p38 MAPK. Stimulation of the Nrf2 system by tBHQ was partly intact after 24 h but blocked after 72 h treatment with MCM(10) and MCM(100) . This down-regulation after 72 h correlated with activation of p38 MAPK and lack of ERK1/2 and JNK activation. The negative effects were partly reversed by an inhibitor of p38 which restored tBHQ mediated protection against oxidative stress. In conclusion, the study showed a negative effect of MCM(10) on the inducible anti-oxidant defense in astrocyte-rich cultures at both 24 and 72 h that correlated with activation of p38 and was partly reversed by a p38 inhibitor. A transient protective effect of MCM(100) on astrocyte-rich cultures against H(2)O(2) toxicity was observed at 24 h which coincided with activation of JNK and ERK1/2.
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| 2. |
- Correa, Fernando, et al.
(författare)
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Time-Dependent Effects of Systemic Lipopolysaccharide Injection on Regulators of Antioxidant Defence Nrf2 and PGC-1α in the Neonatal Rat Brain.
- 2013
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Ingår i: Neuroimmunomodulation. - : S. Karger AG. - 1423-0216 .- 1021-7401. ; 20:4, s. 185-193
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Tidskriftsartikel (refereegranskat)abstract
- Background/Aims: Both excitotoxicity and neuroinflammation are associated with oxidative stress. One transcription factor, nuclear factor E2-related factor 2 (Nrf2), and one transcription cofactor, peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α), increase the endogenous antioxidant defence and can thus modulate neuronal cell death. Here, we investigated the temporal effects (after 24 and 72 h) of systemic (i.p.) administration of lipopolysaccharide (LPS) on the cerebral Nrf2 and PGC-1α systems. Methods and Results: Seven-day-old rat pups were injected with LPS (0.3 mg/kg). After 24 h, the protein levels of γ-glutamylcysteine ligase modulatory subunit, γ-glutamylcysteine ligase catalytic subunit, Nrf2, PGC-1α and manganese superoxide dismutase (MnSOD) were increased in parallel with decreased levels of Keap1. These effects were correlated with an increased level of phosphorylated Akt and elevated acetylation of histone 4. In contrast, 72 h following LPS, a decrease in the components of the Nrf2 system in parallel with an increase in Keap1 was observed. The down-regulation after 72 h correlated with phosphorylation of p38 mitogen-activated protein kinase, while there were no changes in PGC-1α and MnSOD protein levels or the acetylation/methylation pattern of histones. Conclusion: Systemic LPS in neonatal rats induced time-dependent changes in brain Nrf2 and PGC-1α that correlated well with the protective effect observed after 24 h (pre-conditioning) and the deleterious effects observed after 72 h (sensitizing) of systemic LPS reported earlier. Collectively, the results point towards Nrf2 and PGC-1α as a possible mechanism behind these effects.
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| 3. |
- Estrada, Karol, et al.
(författare)
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Genome-wide meta-analysis identifies 56 bone mineral density loci and reveals 14 loci associated with risk of fracture.
- 2012
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Ingår i: Nature genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 44:5, s. 491-501
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Tidskriftsartikel (refereegranskat)abstract
- Bone mineral density (BMD) is the most widely used predictor of fracture risk. We performed the largest meta-analysis to date on lumbar spine and femoral neck BMD, including 17 genome-wide association studies and 32,961 individuals of European and east Asian ancestry. We tested the top BMD-associated markers for replication in 50,933 independent subjects and for association with risk of low-trauma fracture in 31,016 individuals with a history of fracture (cases) and 102,444 controls. We identified 56 loci (32 new) associated with BMD at genome-wide significance (P < 5 × 10(-8)). Several of these factors cluster within the RANK-RANKL-OPG, mesenchymal stem cell differentiation, endochondral ossification and Wnt signaling pathways. However, we also discovered loci that were localized to genes not known to have a role in bone biology. Fourteen BMD-associated loci were also associated with fracture risk (P < 5 × 10(-4), Bonferroni corrected), of which six reached P < 5 × 10(-8), including at 18p11.21 (FAM210A), 7q21.3 (SLC25A13), 11q13.2 (LRP5), 4q22.1 (MEPE), 2p16.2 (SPTBN1) and 10q21.1 (DKK1). These findings shed light on the genetic architecture and pathophysiological mechanisms underlying BMD variation and fracture susceptibility.
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| 4. |
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| 5. |
- Jonsson, Lina, 1982, et al.
(författare)
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Mutation screening of melatonin-related genes in patients with autism spectrum disorders.
- 2010
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Ingår i: BMC medical genomics. - : Springer Science and Business Media LLC. - 1755-8794. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: One consistent finding in autism spectrum disorders (ASD) is a decreased level of the pineal gland hormone melatonin and it has recently been demonstrated that this decrease to a large extent is due to low activity of the acetylserotonin O-methyltransferase (ASMT), the last enzyme in the melatonin synthesis pathway. Moreover, mutations in the ASMT gene have been identified, including a splice site mutation, that were associated with low ASMT activity and melatonin secretion, suggesting that the low ASMT activity observed in autism is, at least partly, due to variation within the ASMT gene. METHODS: In the present study, we have investigated all the genes involved in the melatonin pathway by mutation screening of AA-NAT (arylalkylamine N-acetyltransferase), ASMT, MTNR1A, MTNR1B (melatonin receptor 1A and 1B) and GPR50 (G protein-coupled receptor 50), encoding both synthesis enzymes and the three main receptors of melatonin, in 109 patients with autism spectrum disorders (ASD). A cohort of 188 subjects from the general population was used as a comparison group and was genotyped for the variants identified in the patient sample. RESULTS: Several rare variants were identified in patients with ASD, including the previously reported splice site mutation in ASMT (IVS5+2T>C). Of the variants affecting protein sequence, only the V124I in the MTNR1B gene was absent in our comparison group. However, mutations were found in upstream regulatory regions in three of the genes investigated, ASMT, MTNR1A, and MTNR1B. CONCLUSIONS: Our report of another ASD patient carrying the splice site mutation IVS5+2T>C, in ASMT further supports an involvement of this gene in autism. Moreover, our results also suggest that other melatonin related genes might be interesting candidates for further investigation in the search for genes involved in autism spectrum disorders and related neurobehavioral phenotypes. However, further studies of the novel variants identified in this study are warranted to shed light on their potential role in the pathophysiology of these disorders.
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| 6. |
- Liu, Ching-Ti, et al.
(författare)
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Assessment of gene-by-sex interaction effect on bone mineral density
- 2012
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Ingår i: Journal of Bone and Mineral Research. - : Wiley. - 1523-4681 .- 0884-0431. ; 27:10, s. 2051-2064
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Tidskriftsartikel (refereegranskat)abstract
- Sexual dimorphism in various bone phenotypes, including bone mineral density (BMD), is widely observed; however, the extent to which genes explain these sex differences is unclear. To identify variants with different effects by sex, we examined gene-by-sex autosomal interactions genome-wide, and performed expression quantitative trait loci (eQTL) analysis and bioinformatics network analysis. We conducted an autosomal genome-wide meta-analysis of gene-by-sex interaction on lumbar spine (LS) and femoral neck (FN) BMD in 25,353 individuals from 8 cohorts. In a second stage, we followed up the 12 top single-nucleotide polymorphisms (SNPs; p?
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| 7. |
- Paternoster, Lavinia, et al.
(författare)
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Genetic determinants of trabecular and cortical volumetric bone mineral densities and bone microstructure.
- 2013
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Ingår i: PLoS genetics. - : Public Library of Science (PLoS). - 1553-7404 .- 1553-7390. ; 9:2
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Tidskriftsartikel (refereegranskat)abstract
- Most previous genetic epidemiology studies within the field of osteoporosis have focused on the genetics of the complex trait areal bone mineral density (aBMD), not being able to differentiate genetic determinants of cortical volumetric BMD (vBMD), trabecular vBMD, and bone microstructural traits. The objective of this study was to separately identify genetic determinants of these bone traits as analysed by peripheral quantitative computed tomography (pQCT). Separate GWA meta-analyses for cortical and trabecular vBMDs were performed. The cortical vBMD GWA meta-analysis (n=5,878) followed by replication (n=1,052) identified genetic variants in four separate loci reaching genome-wide significance (RANKL, rs1021188, p=3.6×10⁻¹⁴; LOC285735, rs271170, p=2.7×10⁻¹²; OPG, rs7839059, p=1.2×10⁻¹⁰; and ESR1/C6orf97, rs6909279, p=1.1×10⁻⁹). The trabecular vBMD GWA meta-analysis (n=2,500) followed by replication (n=1,022) identified one locus reaching genome-wide significance (FMN2/GREM2, rs9287237, p=1.9×10⁻⁹). High-resolution pQCT analyses, giving information about bone microstructure, were available in a subset of the GOOD cohort (n=729). rs1021188 was significantly associated with cortical porosity while rs9287237 was significantly associated with trabecular bone fraction. The genetic variant in the FMN2/GREM2 locus was associated with fracture risk in the MrOS Sweden cohort (HR per extra T allele 0.75, 95% confidence interval 0.60-0.93) and GREM2 expression in human osteoblasts. In conclusion, five genetic loci associated with trabecular or cortical vBMD were identified. Two of these (FMN2/GREM2 and LOC285735) are novel bone-related loci, while the other three have previously been reported to be associated with aBMD. The genetic variants associated with cortical and trabecular bone parameters differed, underscoring the complexity of the genetics of bone parameters. We propose that a genetic variant in the RANKL locus influences cortical vBMD, at least partly, via effects on cortical porosity, and that a genetic variant in the FMN2/GREM2 locus influences GREM2 expression in osteoblasts and thereby trabecular number and thickness as well as fracture risk.
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| 8. |
- Penno, Hendrik, 1962-, et al.
(författare)
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Polymorphic variations in the gene for osteoprotegerin do not predict prostate cancer incidence: Data from MrOS Sweden.
- 2011
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background Prostate cancer cells have been shown to produce and secrete osteoprotegerin (OPG), that inhibits tumor cell death by binding to TNF-related anti apoptotic ligand (TRAIL), and also is a key regulator of bone turnover . Bone metastases play a central role in prostate cancer spreading. However, the mechanisms underlying the interaction between bone cells and prostate cancer cells are not known. The aim of this study was therefore to investigate whether polymorphic variations in the gene for OPG affect prostate cancer incidence, or extra prostatic disease and metastasis. Methods The study was performed in the MrOS-Sweden cohort consisting of 3,014 men aged 69-81 years. DNA was collected at the start of the study and the gene for OPG was investigated concerning SNPs previously shown to regulate bone mineral density (BMD), and therefore of biological importance. Data on prostate cancer prevalence at baseline, and incidence during a 3-year follow-up were collected from the Swedish Cancer Register. The association of six OPG polymorphisms with prostate cancer was evaluated. Results The association between six OPG polymorphisms and prostate cancer was evaluated. In these analyses there were no significant genotype differences between prostate cancer patients and controls. A tendency for an association between OPG genotypes and more severe disease (p=0.08-0.09) was found however regarding OPG genotypes. Conclusion Polymorphic variations in the gene for OPG are not associated with prostate cancer incidence. Our data on staging of prostate cancer at the diagnose according to the TNM system in regard to the variations in the OPG gene gave some tendencies to possible involvement but further studies are required to investigate the potential role of the OPG/RANK/RANKL system in the metastatic skeletal prostate cancer spreading, and growth, in bone.
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