| 61. |
- Aoyagi, Atsushi, et al.
(författare)
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A beta and tau prion-like activities decline with longevity in the Alzheimer's disease human brain
- 2019
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Ingår i: Science Translational Medicine. - : AMER ASSOC ADVANCEMENT SCIENCE. - 1946-6234 .- 1946-6242. ; 11:490
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Tidskriftsartikel (refereegranskat)abstract
- The hallmarks of Alzheimer's disease (AD) are the accumulation of A beta plaques and neurofibrillary tangles composed of hyperphosphorylated tau. We developed sensitive cellular assays using human embryonic kidney-293T cells to quantify intracellular self-propagating conformers of A beta in brain samples from patients with AD or other neurodegenerative diseases. Postmortem brain tissue from patients with AD had measurable amounts of pathological A beta conformers. Individuals over 80 years of age had the lowest amounts of prion-like A beta and phosphorylated tau. Unexpectedly, the longevity-dependent decrease in self-propagating tau conformers occurred in spite of increasing amounts of total insoluble tau. When corrected for the abundance of insoluble tau, the ability of postmortem AD brain homogenates to induce misfolded tau in the cellular assays showed an exponential decrease with longevity, with a half-life of about one decade over the age range of 37 to 99 years. Thus, our findings demonstrate an inverse correlation between longevity in patients with AD and the abundance of pathological tau conformers. Our cellular assays can be applied to patient selection for clinical studies and the development of new drugs and diagnostics for AD.
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| 62. |
- Basun, Hans, et al.
(författare)
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Clinical and neuropathological features of the arctic APP gene mutation causing early-onset Alzheimer disease
- 2008
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Ingår i: Archives of neurology. - : American Medical Association (AMA). - 0003-9942 .- 1538-3687. ; 65:4, s. 499-505
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: A majority of mutations within the beta-amyloid region of the amyloid precursor protein (APP) gene cause inherited forms of intracerebral hemorrhage. Most of these mutations may also cause cognitive impairment, but the Arctic APP mutation is the only known intra-beta-amyloid mutation to date causing the more typical clinical picture of Alzheimer disease. OBJECTIVE: To describe features of 1 Swedish and 1 American family with the previously reported Arctic APP mutation. DESIGN, SETTING, AND PARTICIPANTS: Affected and nonaffected carriers of the Arctic APP mutation from the Swedish and American families were investigated clinically. In addition, 1 brain from each family was investigated neuropathologically. RESULTS: The clinical picture, with age at disease onset in the sixth to seventh decade of life and dysfunction in multiple cognitive areas, is indicative of Alzheimer disease and similar to the phenotype for other Alzheimer disease APP mutations. Several affected mutation carriers displayed general brain atrophy and reduced blood flow of the parietal lobe as demonstrated by magnetic resonance imaging and single-photon emission computed tomography. One Swedish case and 1 American case with the Arctic APP mutation came to autopsy, and both showed no signs of hemorrhage but revealed severe congophilic angiopathy, region-specific neurofibrillary tangle pathological findings, and abundant amyloid plaques. Intriguingly, most plaques from both of these cases had a characteristic ringlike character. CONCLUSIONS: Overall, our findings corroborate that the Arctic APP mutation causes a clinical and neuropathological picture compatible with Alzheimer disease.
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| 63. |
- Behere, Anish, et al.
(författare)
-
A proximity ligation assay recognizing phosphorylated α-syn reveals previously undetected α-syn pathology in the brains of synucleinopathy patients and mouse model.
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Aim: To enhance detection sensitivity of phosphorylated α-synuclein (pSynS129) on post mortem synucleinopathy brains using the newly developed PLA and characterize possible ‘strain’-specific differences in the synucleinopathy brains.Experimental plan: Four different antibodies detecting different epitopes from N- to C- terminal of α-syn were paired systematically with an antibody detecting pSynS129 to reveal patho-morphological features of α-syn aggregates on post mortem brain tissue. In addition, we tested the application of our novel PLA technique in the A30P-tg mouse model that shows different types of pSynS129 aggregates in different stages of PD.Results: The PLA experiments revealed a wide distribution of pSynS129 aggregates in post mortem synucleinopathy-patient brains. We observed unique staining patterns on the brain tissue sections using only certain antibody combinations in a PLA setup, which could not be visualized using regular immunohistochemistry. In A30P-tg mice, the morphological pattern of PLA signal indicated an age-progressive, intracellular shift of pSynS129 aggregation species from periphery towards soma in the prefrontal cortex.Significance: Here we demonstrate that employing PLA with certain α-syn antibodies pair combinations can enhance detection sensitivity and specificity of α-syn pathology in the respective synucleinopathies. Additionally, it could be a useful tool to monitor the ‘strain’-specific aggregation and intracellular morphology of α-syn on post mortem brain tissue.
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| 64. |
- Behere, Anish, et al.
(författare)
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Alpha synuclein pre-formed fibrils trigger astrocytic activation prior to intra-neuronal deposition in a seeding mouse model of Parkinson’s disease
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Aim: To monitor temporal evolution of glial and peripheral events occurring, prior to pSynS129 inclusion formation, after a single intra-cranial injection of pre-formed fibrils (PFFs) in the wild-type (wt) mice.Experimental plan: Here we perform intracerebral inoculations with mouse PFFs in wt mice (n=30) to study early pathological and inflammatory events from 1 to 30 days post-injections (dpi) at regular time intervals. The paraffin-fixed brain sections were stained against pSynS129 species with the in house developed proximity ligation assay. Furthermore, studies using different glial and inflammatory markers revealed more information regarding the early cellular interactions involving formation and propagation pSynS129 species.Results: Already after 1 dpi, we observe strong pSynS129 immunoreactivity close the striatal injection site. Intriguingly, this type of staining disappeared with the concurrent formation of peri-nuclear pSynS129 inclusions in motor and piriform cortex, amygdala and periventricular hypothalamus after 14 dpi. Concomitantly, we observed astrocytic activation as early event happening prior to intracellular formation and propagation pSynS129 inclusions in the brain and peripheral organs.Significance: Our study elucidates the temporal relationship regarding inflammation and formation of pSynS129 inclusions. Our results indicate that a single PFF injection is enough to induce astrocytic activation and neuro-inflammatory response that occur prior to intra-neuronal accumulation of misfolded α-syn.
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| 65. |
- Behere, Anish, 1993-
(författare)
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Ex‘PLA’ining the progression of pathological proteins in Alzheimer’s and Parkinson’s diseases : see(d)ing is believing
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Alzheimer’s disease (AD) and Parkinson’s disease (PD) are the two most common forms of neurodegenerative disorders affecting approximately 50 million people worldwide. The underlying neuropathological processes leading to AD and PD share many similarities, i.e. aberrant protein aggregation of tau and alpha-synuclein (αSyn) in the brain. Monitoring tau and αSyn aggregation is challenging, due to morphological heterogeneity of the aggregating species and problems in preserving the antigen conformation ex vivo.In paper-I, we validated the usefulness of proximity ligation assay (PLA), a technique that enabled us to visualize previously undetected early αSyn pathology in the A30P-tg mouse model of PD. We observed an age-progressive increase in the levels of phosphorylated αSyn (pSynS129) and the compactness of aggregates in the brain. Although loss of dopaminergic neurons was not found, a subtle dysregulation of other catecholamines was recorded in the older mice.In paper-II, we revealed a wide distribution of pSynS129 aggregates in alpha-synucleinopathy-patient brains. By using a PLA setup with certain antibody pair combinations on brain sections, we observed unique staining patterns, which could not be visualized using regular immunohistochemistry (IHC). In A30P-tg mice, the morphological pattern of the PLA signals indicated an intracellular shift of pSynS129 from the periphery towards the neuronal soma.In Paper-III, we demonstrated that multiplex pTauS202,T205-pTauT231, singleplex pTauT231 and singleplex pSynS129 PLAs can recognize an extensive tau and αSyn pathology compared to regular IHC. We found that using our PLA approach we could differentiate between pTauS202,T205 and pTauT231 pathology in AD brains, whereas IHC could not. Similarly, in the PD brain, singleplex pSynS129 PLA detected novel structures, i.e. apparent thick intercellular tunnelling nanotubes and early aggregates; whereas pSynS129 IHC was limited to the detection of mature pathology. Lastly, we demonstrated that our multiplex PLA approach detected co-aggregates of pSynS129-pTau.In Paper-IV, in an αSyn seeding mouse model we observed pSynS129 immunoreactivity close to the striatal injection site one day post-injection (dpi). Intriguingly, this type of staining disappeared with the concurrent formation of peri-nuclear pSynS129 inclusions in specific brain regions after 14 dpi. In parallel, astrocytic activation prior to pSynS129 inclusion formation was observed.In conclusion, we have developed several novel PLAs that detect both tau and αSyn pathology with a higher ex vivo sensitivity and specificity than currently used immunostaining methods. This thesis work provides valuable insights that potentially could be used for the development of future biomarkers for tauopathies and synucleinopathies.
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| 66. |
- Behere, Anish, et al.
(författare)
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Novel visualization of phosphorylated tau and alpha-synuclein aggregates in the Alzheimer’s disease and Parkinson’s disease brain
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Several neurodegenerative diseases, such as Alzheimer’s disease (AD) and Parkinson’s disease (PD), display deposits of phosphorylated tau (pTau) and/or alpha-synuclein (pSyn) in affected parts of the brain. However, the pathological and morphological properties of these protein aggregates remain poorly characterized, due to lack of specificity and sensitivity of in situ detection techniques. The aim of this study was to investigate the patho-morphological properties of phosphorylated tau and α-syn aggregates on AD and PD brain tissues with a novel sensitive in situ proximity ligation assay (PLA) technique. We took advantage of the sensitivity and <40 nm resolution of PLA, along with the selectivity of different antibodies directed against pTau and pSyn epitopes. Most notably, multiplex pTauS202, T205-pTauT231, singleplex pTauT231 and pSynS129 PLA recognized more extensive phosphorylated tau and αSyn pathology, compared to conventional immunohistochemistry (IHC) using the same antibodies on adjacent brain sections. Furthermore, singleplex pTauT231 PLA captured additional pathological aggregates compared to the singleplex pTauS202, T205 PLA in late Braak stage AD brains, where traditional IHC failed to distinguish between pTauS202, T205 and pTauT231 pathology. Similarly, in PD brains, singleplex pSynS129 PLA detected novel pathological structures, such as intercellular thick tunneling nanotubes and pre-Lewy body intracytoplasmic aggregates, whereas pSynS129 IHC was limited to the detection of mature Lewy body/neurite pathology. Lastly, we could demonstrate that our dual PLA approach also can be applied to detect co-aggregates of pSyn-pTau.
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| 67. |
- Behere, Anish, 1993-, et al.
(författare)
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Visualization of early oligomeric α‐synuclein pathology and its impact on the dopaminergic system in the (Thy‐1)‐h[A30P]α‐syn transgenic mouse model
- 2021
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Ingår i: Journal of Neuroscience Research. - : John Wiley & Sons. - 0360-4012 .- 1097-4547. ; 99:10, s. 2525-2539
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Tidskriftsartikel (refereegranskat)abstract
- Aggregation of alpha-synuclein (alpha-syn) into Lewy bodies and Lewy neurites is a pathological hallmark in the Parkinson ' s disease (PD) brain. The formation of alpha-syn oligomers is believed to be an early pathogenic event and the A30P mutation in the gene encoding alpha-syn, causing familial PD, has been shown to cause an accelerated oligomerization. Due to the problem of preserving antigen conformation on tissue surfaces, alpha-syn oligomers are difficult to detect ex vivo using conventional immunohistochemistry with oligomer-selective antibodies. Herein, we have instead employed the previously reported alpha-syn oligomer proximity ligation assay (ASO-PLA), along with a wide variety of biochemical assays, to discern the pathological progression of alpha-syn oligomers and their impact on the dopaminergic system in male and female (Thy-1)-h[A30P]alpha-syn transgenic (A30P-tg) mice. Our results reveal a previously undetected abundance of alpha-syn oligomers in midbrain of young mice, whereas phosphorylated (pS129) and proteinase k-resistant alpha-syn species were observed to a larger extent in aged mice. Although we did not detect loss of dopaminergic neurons in A30P-tg mice, a dysregulation in the monoaminergic system was recorded in older mice. Taken together, ASO-PLA should be a useful method for the detection of early changes in alpha-syn aggregation on brain tissue, from experimental mouse models in addition to post mortem PD cases.
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| 68. |
- Belloy, Michael E., et al.
(författare)
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Challenges at the APOE locus : a robust quality control approach for accurate APOE genotyping
- 2022
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Ingår i: Alzheimer's Research & Therapy. - : Springer Nature. - 1758-9193. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Genetic variants within the APOE locus may modulate Alzheimer's disease (AD) risk independently or in conjunction with APOE*2/3/4 genotypes. Identifying such variants and mechanisms would importantly advance our understanding of APOE pathophysiology and provide critical guidance for AD therapies aimed at APOE. The APOE locus however remains relatively poorly understood in AD, owing to multiple challenges that include its complex linkage structure and uncertainty in APOE*2/3/4 genotype quality. Here, we present a novel APOE*2/3/4 filtering approach and showcase its relevance on AD risk association analyses for the rs439401 variant, which is located 1801 base pairs downstream of APOE and has been associated with a potential regulatory effect on APOE.Methods: We used thirty-two AD-related cohorts, with genetic data from various high-density single-nucleotide polymorphism microarrays, whole-genome sequencing, and whole-exome sequencing. Study participants were filtered to be ages 60 and older, non-Hispanic, of European ancestry, and diagnosed as cognitively normal or AD (n = 65,701). Primary analyses investigated AD risk in APOE*4/4 carriers. Additional supporting analyses were performed in APOE*3/4 and 3/3 strata. Outcomes were compared under two different APOE*2/3/4 filtering approaches.Results: Using more conventional APOE*2/3/4 filtering criteria (approach 1), we showed that, when in-phase with APOE*4, rs439401 was variably associated with protective effects on AD case-control status. However, when applying a novel filter that increases the certainty of the APOE*2/3/4 genotypes by applying more stringent criteria for concordance between the provided APOE genotype and imputed APOE genotype (approach 2), we observed that all significant effects were lost. Conclusions: We showed that careful consideration of APOE genotype and appropriate sample filtering were crucial to robustly interrogate the role of the APOE locus on AD risk. Our study presents a novel APOE filtering approach and provides important guidelines for research into the APOE locus, as well as for elucidating genetic interaction effects with APOE*2/3/4.
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| 69. |
- Beretta, Chiara, et al.
(författare)
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Extracellular vesicles from amyloid-beta exposed cell cultures induce severe dysfunction in cortical neurons
- 2020
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Ingår i: Scientific Reports. - : NATURE RESEARCH. - 2045-2322. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease (AD) is characterized by a substantial loss of neurons and synapses throughout the brain. The exact mechanism behind the neurodegeneration is still unclear, but recent data suggests that spreading of amyloid-beta (A beta) pathology via extracellular vesicles (EVs) may contribute to disease progression. We have previously shown that an incomplete degradation of A beta (42) protofibrils by astrocytes results in the release of EVs containing neurotoxic A beta. Here, we describe the cellular mechanisms behind EV-associated neurotoxicity in detail. EVs were isolated from untreated and A beta (42) protofibril exposed neuroglial co-cultures, consisting mainly of astrocytes. The EVs were added to cortical neurons for 2 or 4 days and the neurodegenerative processes were followed with immunocytochemistry, time-lapse imaging and transmission electron microscopy (TEM). Addition of EVs from A beta (42) protofibril exposed co-cultures resulted in synaptic loss, severe mitochondrial impairment and apoptosis. TEM analysis demonstrated that the EVs induced axonal swelling and vacuolization of the neuronal cell bodies. Interestingly, EV exposed neurons also displayed pathological lamellar bodies of cholesterol deposits in lysosomal compartments. Taken together, our data show that the secretion of EVs from A beta exposed cells induces neuronal dysfunction in several ways, indicating a central role for EVs in the progression of A beta -induced pathology.
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| 70. |
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