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| 2. |
- Hollerhage, M., et al.
(författare)
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Piericidin A Aggravates Tau Pathology in P301S Transgenic Mice
- 2014
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 9:12
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The P301S mutation in exon 10 of the tau gene causes a hereditary tauopathy. While mitochondrial complex I inhibition has been linked to sporadic tauopathies. Piericidin A is a prototypical member of the group of the piericidins, a class of biologically active natural complex I inhibitors, isolated from streptomyces spp. with global distribution in marine and agricultural habitats. The aim of this study was to determine whether there is a pathogenic interaction of the environmental toxin piericidin A and the P301S mutation. Methods: Transgenic mice expressing human tau with the P301S-mutation (P301S(+/+)) and wild-type mice at 12 weeks of age were treated subcutaneously with vehicle (N=10 P301S(+/+), N = 7 wild-type) or piericidin A (N = 9 P301S(+/+), N = 9 wild-type mice) at a dose of 0.5 mg/kg/d for a period of 28 days via osmotic minipumps. Tau pathology was measured by stereological counts of cells immunoreative with antibodies against phosphorylated tau (AD2, AT8, AT180, and AT100) and corresponding Western blot analysis. Results: Piericidin A significantly increased the number of phospho-tau immunoreactive cells in the cerebral cortex in P301S(+/+) mice, but only to a variable and mild extent in wild-type mice. Furthermore, piericidin A led to increased levels of pathologically phosphorylated tau only in P301S(+/+) mice. While we observed no apparent cell loss in the frontal cortex, the synaptic density was reduced by piericidin A treatment in P301S(+/+) mice. Discussion: This study shows that exposure to piericidin A aggravates the course of genetically determined tau pathology, providing experimental support for the concept of gene-environment interaction in the etiology of tauopathies.
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| 4. |
- Gozes, I, et al.
(författare)
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Tau Diagnostics and Clinical Studies
- 2017
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Ingår i: Journal of molecular neuroscience : MN. - : Springer Science and Business Media LLC. - 1559-1166 .- 0895-8696. ; 63:2, s. 123-130
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Keber, U., et al.
(författare)
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STRIATAL TYROSINE HYDROXYLASE-POSITIVE NEURONS ARE ASSOCIATED WITH L-DOPA-INDUCED DYSKINESIA IN HEMIPARKINSONIAN MICE
- 2015
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Ingår i: Neuroscience. - : Elsevier BV. - 0306-4522. ; 298, s. 302-317
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Tidskriftsartikel (refereegranskat)abstract
- L-3,4-Dihydroxyphenylalanine (L-DOPA) is the therapeutic gold standard in Parkinson's disease. However, long-term treatment is complicated by the induction of debilitating abnormal involuntary movements termed L-DOPA-induced dyskinesias (LIDs). Until today the underlying mechanisms of LID pathogenesis are not fully understood. The aim of this study was to reveal new factors, which may be involved in the induction of LID. We have focused on the expression of striatal tyrosine hydroxylase-positive (TH+) neurons, which are capable of producing either L-DOPA or dopamine (DA) in target areas of ventral midbrain DAergic neurons. To address this issue, a daily L-DOPA dose was administered over the course of 15 days to mice with unilateral 6-hydroxydopamine-induced lesions of the medial forebrain bundle and LIDs were evaluated. Remarkably, the number of striatal TH+ neurons strongly correlated with both induction and severity of LID as well as Delta FosB expression as an established molecular marker for LID. Furthermore, dyskinetic mice showed a marked augmentation of serotonergic fiber innervation in the striatum, enabling the decarboxylation of L-DOPA to DA. Axial, limb and orolingual dyskinesias were predominantly associated with TH+ neurons in the lateral striatum, whereas medially located TH+ neurons triggered locomotive rotations. In contrast, identified accumbal and cortical TH+ cells did not contribute to the generation of LID. Thus, striatal TH+ cells and serotonergic terminals may cooperatively synthesize DA and subsequently contribute to supraphysiological synaptic DA concentrations, an accepted cause in LID pathogenesis. (C) 2015 IBRO. Published by Elsevier Ltd. All rights reserved.
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| 6. |
- Klietz, M., et al.
(författare)
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L-DOPA-INDUCED DYSKINESIA IS ASSOCIATED WITH A DEFICIENT NUMERICAL DOWNREGULATION OF STRIATAL TYROSINE HYDROXYLASE mRNA-EXPRESSING NEURONS
- 2016
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Ingår i: Neuroscience. - : Elsevier BV. - 0306-4522. ; 331, s. 120-133
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Tidskriftsartikel (refereegranskat)abstract
- L-3,4-Dihydroxyphenylalanine (L-DOPA) is the therapeutic gold standard in Parkinson's disease. However, most patients develop debilitating abnormal involuntary movements termed L-DOPA-induced dyskinesia (LID) as therapy-complicating side effects. The underlying mechanisms of LID pathogenesis are still not fully understood. Recent evidence suggests an involvement of striatal tyrosine hydroxylase (TH) protein-expressing neurons, as they are capable of endogenously producing L-DOPA and possibly dopamine. The aim of this study was to elucidate changes of TH transcription in the striatum and nucleus accumbens that occur under experimental conditions of LID. Mice with a unilateral 6-hydroxydopamine-induced lesion of the medial forebrain bundle were treated daily with L-DOPA for 15 days to provoke dyskinesia. In situ hybridization analysis revealed a significant numerical decrease of TH mRNA-positive neurons in the striatum and nucleus accumbens of mice not exhibiting LID, whereas dyskinetic animals failed to show this reduction of TH transcription. Interestingly, similar changes were observed in intact non-deafferentiated striata, demonstrating an L-DOPA-responsive transcriptional TH regulation independently from nigrostriatal lesion severity. Consolidation with our previous study on TH protein level (Keber et al., 2015) impressively highlights that LID is associated with both a deficient downregulation of TH transcription and an excessive translation of TH protein in intrastriatal neurons. As TH protein levels in comparison to mRNA levels showed a stronger correlation with development and severity of LID, antidyskinetic treatment strategies should focus on translational and posttranslational modulations of TH as a promising target.
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| 8. |
- Xu, H., et al.
(författare)
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Tau Silencing by siRNA in the P301S Mouse Model of Tauopathy
- 2014
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Ingår i: Current Gene Therapy. - : Bentham Science Publishers Ltd.. - 1566-5232. ; 14:5, s. 343-351
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Tidskriftsartikel (refereegranskat)abstract
- Suppression of tau protein expression has been shown to improve behavioral deficits in mouse models of tauopathies, offering an attractive therapeutic approach. Experimentally this had been achieved by switching off the promoters controlling the transgenic human tau gene (MAPT), which is not possible in human patients. The aim of the present study was therefore to evaluate the effectiveness of small interfering RNAs (siRNAs) and their cerebral delivery to suppress human tau expression in vivo, which might be a therapeutic option for human tauopathies. We used primary cortical neurons of transgenic mice expressing P301S-mutated human tau and Lund human mesencephalic (LUHMES) cells to validate the suppressive effect of siRNA in vitro. For measuring the effect in vivo, we stereotactically injected siRNA into the brains of P301S mice to reveal the suppression of tau by immunochemistry (AT180, MC1, and CP13 antibodies). We found that the Accell((TM)) SMART pool siRNA against MAPT can effectively suppress tau expression in vitro and in vivo without a specific delivery agent. The siRNA showed a moderate distribution in the hippocampus of mice after single injection. NeuN, GFAP, Iba-1, MHC II immunoreactivities and the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay showed neither signs of neurotoxicity or neuroinflammation nor apoptosis when MAPT siRNA is present in the hippocampus. Our data suggest that siRNA against MAPT can serve as a potential tool for gene therapy in tauopathies.
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