| 1. |
- Finckenberg, Piet, et al.
(författare)
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Caloric restriction ameliorates angiotensin II-induced mitochondrial remodeling and cardiac hypertrophy
- 2012
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Ingår i: Hypertension. - : Lippincott Williams & Wilkins. - 0194-911X .- 1524-4563. ; 59:1, s. 76-84
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Tidskriftsartikel (refereegranskat)abstract
- Angiotensin II-induced cardiac damage is associated with oxidative stress-dependent mitochondrial dysfunction. Caloric restriction (CR), a dietary regimen that increases mitochondrial activity and cellular stress resistance, could provide protection. We tested that hypothesis in double transgenic rats harboring human renin and angiotensinogen genes (dTGRs). CR (60% of energy intake for 4 weeks) decreased mortality in dTGRs. CR ameliorated angiotensin II-induced cardiomyocyte hypertrophy, vascular inflammation, cardiac damage and fibrosis, cardiomyocyte apoptosis, and cardiac atrial natriuretic peptide mRNA overexpression. The effects were blood pressure independent and were linked to increased endoplasmic reticulum stress, autophagy, serum adiponectin level, and 5' AMP-activated protein kinase phosphorylation. CR decreased cardiac p38 phosphorylation, nitrotyrosine expression, and serum insulin-like growth factor 1 levels. Mitochondria from dTGR hearts showed clustered mitochondrial patterns, decreased numbers, and volume fractions but increased trans-sectional areas. All of these effects were reduced in CR dTGRs. Mitochondrial proteomic profiling identified 43 dTGR proteins and 42 Sprague-Dawley proteins, of which 29 proteins were in common in response to CR. We identified 7 proteins in CR dTGRs that were not found in control dTGRs. In contrast, 6 mitochondrial proteins were identified from dTGRs that were not detected in any other group. Gene ontology annotations with the Panther protein classification system revealed downregulation of cytoskeletal proteins and enzyme modulators and upregulation of oxidoreductase activity in dTGRs. CR provides powerful, blood pressure-independent, protection against angiotensin II-induced mitochondrial remodeling and cardiac hypertrophy. The findings support the notion of modulating cardiac bioenergetics to ameliorate angiotensin II-induced cardiovascular complications.
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| 2. |
- Hosp, Fabian, et al.
(författare)
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Quantitative Interaction Proteomics of Neurodegenerative Disease Proteins
- 2015
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Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247. ; 11:7, s. 1134-1146
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Tidskriftsartikel (refereegranskat)abstract
- Several proteins have been linked to neurodegenerative disorders (NDDs), but their molecular function is not completely understood. Here, we used quantitative interaction proteomics to identify binding partners of Amyloid beta precursor protein (APP) and Presenilin-1 (PSEN1) for Alzheimer's disease (AD), Huntingtin (HTT) for Huntington's disease, Parkin (PARK2) for Parkinson's disease, and Ataxin-1 (ATXN1) for spinocerebellar ataxia type 1. Our network reveals common signatures of protein degradation and misfolding and recapitulates known biology. Toxicity modifier screens and comparison to genome-wide association studies show that interaction partners are significantly linked to disease phenotypes in vivo. Direct comparison of wild-type proteins and disease-associated variants identified binders involved in pathogenesis, highlighting the value of differential interactome mapping. Finally, we show that the mitochondrial protein LRPPRC interacts preferentially with an early-onset AD variant of APP. This interaction appears to induce mitochondrial dysfunction, which is an early phenotype of AD.
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| 3. |
- Kalimo, Hannu, et al.
(författare)
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The Arctic AβPP mutation leads to Alzheimer's disease pathology with highly variable topographic deposition of differentially truncated Aβ
- 2013
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Ingår i: Acta neuropathologica communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 1:1, s. 60-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The Arctic mutation (p.E693G/p.E22G)fs within the β-amyloid (Aβ) region of the β-amyloid precursor protein gene causes an autosomal dominant disease with clinical picture of typical Alzheimer's disease. Here we report the special character of Arctic AD neuropathology in four deceased patients.RESULTS: Aβ deposition in the brains was wide-spread (Thal phase 5) and profuse. Virtually all parenchymal deposits were composed of non-fibrillar, Congo red negative Aβ aggregates. Congo red only stained angiopathic vessels. Mass spectrometric analyses showed that Aβ deposits contained variably truncated and modified wild type and mutated Aβ species. In three of four Arctic AD brains, most cerebral cortical plaques appeared targetoid with centres containing C-terminally (beyond aa 40) and variably N-terminally truncated Aβ surrounded by coronas immunopositive for Aβx-42. In the fourth patient plaque centres contained almost no Aβ making the plaques ring-shaped. The architectural pattern of plaques also varied between different anatomic regions. Tau pathology corresponded to Braak stage VI, and appeared mainly as delicate neuropil threads (NT) enriched within Aβ plaques. Dystrophic neurites were scarce, while neurofibrillary tangles were relatively common. Neuronal perikarya within the Aβ plaques appeared relatively intact.CONCLUSIONS: In Arctic AD brain differentially truncated abundant Aβ is deposited in plaques of variable numbers and shapes in different regions of the brain (including exceptional targetoid plaques in neocortex). The extracellular non-fibrillar Aβ does not seem to cause overt damage to adjacent neurons or to induce formation of neurofibrillary tangles, supporting the view that intracellular Aβ oligomers are more neurotoxic than extracellular Aβ deposits. However, the enrichment of NTs within plaques suggests some degree of intra-plaque axonal damage including accumulation of hp-tau, which may impair axoplasmic transport, and thereby contribute to synaptic loss. Finally, similarly as the cotton wool plaques in AD resulting from exon 9 deletion in the presenilin-1 gene, the Arctic plaques induced only modest glial and inflammatory tissue reaction.
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| 4. |
- Makela, Johanna, et al.
(författare)
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Peroxisome proliferator-activated receptor-gamma coactivator-1 alpha mediates neuroprotection against excitotoxic brain injury in transgenic mice : role of mitochondria and X-linked inhibitor of apoptosis protein
- 2016
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Ingår i: European Journal of Neuroscience. - : WILEY. - 0953-816X .- 1460-9568. ; 43:5, s. 626-639
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Tidskriftsartikel (refereegranskat)abstract
- Peroxisome proliferator-activated receptor gamma coactivator-1 (PGC-1) is a transcriptional coactivator involved in the regulation of mitochondrial biogenesis and cell defense. The functions of PGC-1 in physiology of brain mitochondria are, however, not fully understood. To address this we have studied wild-type and transgenic mice with a two-fold overexpression of PGC-1 in brain neurons. Data showed that the relative number and basal respiration of brain mitochondria were increased in PGC-1 transgenic mice compared with wild-type mitochondria. These changes occurred concomitantly with altered levels of proteins involved in oxidative phosphorylation (OXPHOS) as studied by proteomic analyses and immunoblottings. Cultured hippocampal neurons from PGC-1 transgenic mice were more resistant to cell degeneration induced by the glutamate receptor agonist kainic acid. In vivo kainic acid induced excitotoxic cell death in the hippocampus at 48h in wild-type mice but significantly less so in PGC-1 transgenic mice. However, at later time points cell degeneration was also evident in the transgenic mouse hippocampus, indicating that PGC-1 overexpression can induce a delay in cell death. Immunoblotting showed that X-linked inhibitor of apoptosis protein (XIAP) was increased in PGC-1 transgenic hippocampus with no significant changes in Bcl-2 or Bcl-X. Collectively, these results show that PGC-1 overexpression contributes to enhanced neuronal viability by stimulating mitochondria number and respiration and increasing levels of OXPHOS proteins and the anti-apoptotic protein XIAP.
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| 5. |
- Philipson, Ola, 1979-, et al.
(författare)
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Biochemical and morphological analyses of Aβ deposits in postmortem brain of Arctic APP mutation carriers
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The clinical symptoms associated with the Arctic (E693G) mutation in the amyloid-β precursor protein (APP) are those of typical Alzheimer’s disease (AD), beginning with insidious loss of recent memories. However, an unusual neuropathology of ring-like amyloid-β (Aβ) plaques is identified in postmortem brain. Here, the neuropathology of subjects carrying the Arctic mutation was compared to that of sporadic AD. Different types of Aβ-deposits were examined with light, confocal and electron microscopy, and their composition was analyzed with biochemical techniques. Parenchymal deposits of the Arctic mutant brain were homogenous in structure, lacked an amyloid core and were immunostained differentially by antibodies recognizing C- or N-terminal epitopes of Aβ. Superficially, Arctic Aβ plaques bore considerable resemblance to cotton wool plaques (CWP), namely their large size, the presence of healthy neuronal nuclei and the absence of marked neuritic dystrophy within the plaques, and the sparsity of astro- or microgliosis in the surrounding tissue. Both parenchymal deposits and cerebral amyloid angiopathy of Arctic mutant brain contained a mixture of Arctic and wild-type Aβ. While Aβ peptides in parenchymal plaques were often N-terminally truncated, a substantial amount of full-length Aβ1-40 was deposited in the vessel walls as cerebral amyloid angiopathy (CAA). Thus, the absence of amyloid cores in parenchymal plaques of Arctic mutant brain was likely due to the scarcity of full-length Aβ species, although other mechanisms could also be involved. Our findings are discussed in relation to the clinical features of patients carrying the Arctic mutation and neuropathological observations made with other intra-Aβ mutations in human and transgenic mouse brain.
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| 6. |
- Philipson, Ola, et al.
(författare)
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The Arctic amyloid-β precursor protein (AβPP) mutation results in distinct plaques and accumulation of N- and C-truncated Aβ
- 2012
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 33:5, s. 1010.e1-1010.e13
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Tidskriftsartikel (refereegranskat)abstract
- The Arctic (p. E693G) mutation in the amyloid-β precursor protein (AβPP) facilitates amyloid-β (Aβ) protofibril formation and generates clinical symptoms of Alzheimer's disease (AD). Here, molecular details of Aβ in post mortem brain were investigated with biochemical and morphological techniques. The basic structure of Arctic plaques resembled cotton wool plaques. However, they appeared ring-formed with Aβ42-specific antibodies, but were actually targetoid, since the periphery and center of many parenchymal Aβ deposits stained differently with mid-domain, N- and C-terminal Aβ antibodies. Aβ fibrils were similar in shape, albeit shorter than in sporadic AD brain, when examined by electron microscopy. Aβwild-type and Aβarctic codeposited and parenchymal deposits were highly enriched in both N- and C-terminally truncated Aβ. In contrast, cerebral amyloid angiopathy (CAA) contained a substantial amount of Aβ1-40. The absence of plaques with cores of fibrillary Aβ might be due to the scarcity of full-length Aβ, although other mechanisms could be involved. Our findings are discussed in relation to mechanisms and relevance of amyloid formation and to the clinical features of AD.
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| 7. |
- Vanaveski, Taavi, et al.
(författare)
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PGC-1 alpha Signaling Increases GABA(A) Receptor Subunit alpha 2 Expression, GABAergic Neurotransmission and Anxiety-Like Behavior in Mice
- 2021
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Ingår i: Frontiers in Molecular Neuroscience. - : FRONTIERS MEDIA SA. - 1662-5099. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1 alpha) is a master regulator of mitochondria biogenesis and cell stress playing a role in metabolic and degenerative diseases. In the brain PGC-1 alpha expression has been localized mainly to GABAergic interneurons but its overall role is not fully understood. We observed here that the protein levels of gamma-aminobutyric acid (GABA) type A receptor-alpha 2 subunit (GABAR alpha 2) were increased in hippocampus and brain cortex in transgenic (Tg) mice overexpressing PGC-1 alpha in neurons. Along with this, GABAR alpha 2 expression was enhanced in the hippocampus of the PGC-1 alpha Tg mice, as shown by quantitative PCR. Double immunostaining revealed that GABAR alpha 2 co-localized with the synaptic protein gephyrin in higher amounts in the striatum radiatum layer of the hippocampal CA1 region in the Tg compared with Wt mice. Electrophysiology revealed that the frequency of spontaneous and miniature inhibitory postsynaptic currents (mIPSCs) was increased in the CA1 region in the Tg mice, indicative of an augmented GABAergic transmission. Behavioral tests revealed an increase for anxiety-like behavior in the PGC-1 alpha Tg mice compared with controls. To study whether drugs acting on PPAR gamma can affect GABAR alpha 2, we employed pioglitazone that elevated GABAR alpha 2 expression in primary cultured neurons. Similar results were obtained using the specific PPAR gamma agonist, N-(2-benzoylphenyl)-O-[2-(methyl-2-pyridinylamino) ethyl]-L-tyrosine hydrate (GW1929). These results demonstrate that PGC-1 alpha regulates GABAR alpha 2 subunits and GABAergic neurotransmission in the hippocampus with behavioral consequences. This indicates further that drugs like pioglitazone, widely used in the treatment of type 2 diabetes, can influence GABAR alpha 2 expression via the PPAR gamma/PGC-1 alpha system.
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