| 1. |
- Falsig, Jeppe, et al.
(författare)
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Chemical and biophysical insights into the propagation of prion strains
- 2008
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Ingår i: HFSP JOURNAL. - : Informa UK Limited. - 1955-2068. ; 2:6, s. 332-341
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Tidskriftsartikel (refereegranskat)abstract
- Transmissible spongiform encephalopathies (TSEs) are lethal infectious neurodegenerative diseases. TSEs are caused by prions, infectious agents lacking informational nucleic acids, and possibly identical with higher-order aggregates of the cellular glycolipoprotein PrPC. Prion strains are derived from TSE isolates that, even after inoculation into genetically identical hosts, cause disease with distinct patterns of protein aggregate deposition, incubation times, morphology of the characteristic brain damage, and cellular tropism. Most of these traits are relatively stable across serial passages. Here we review current techniques for studying prion strain differences in vivo and in cells, and discuss the strain phenomena in the general context of the knowledge gained from modeling prion fibril growth in vitro and in simple organisms.
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| 2. |
- Herrmann, Uli S., et al.
(författare)
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Structure-based drug design identifies polythiophenes as antiprion compounds
- 2015
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Ingår i: Science Translational Medicine. - : AMER ASSOC ADVANCEMENT SCIENCE. - 1946-6234 .- 1946-6242. ; 7:299, s. 299ra123-
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Tidskriftsartikel (refereegranskat)abstract
- Prions cause transmissible spongiform encephalopathies for which no treatment exists. Prions consist of PrPSc, a misfolded and aggregated form of the cellular prion protein (PrPC). We explore the antiprion properties of luminescent conjugated polythiophenes (LCPs) that bind and stabilize ordered protein aggregates. By administering a library of structurally diverse LCPs to the brains of prion-infected mice via osmotic minipumps, we found that antiprion activity required a minimum of five thiophene rings bearing regularly spaced carboxyl side groups. Solid-state nuclear magnetic resonance analyses and molecular dynamics simulations revealed that anionic side chains interacted with complementary, regularly spaced cationic amyloid residues of model prions. These findings allowed us to extract structural rules governing the interaction between LCPs and protein aggregates, which we then used to design a new set of LCPs with optimized binding. The new set of LCPs showed robust prophylactic and therapeutic potency in prion-infected mice, with the lead compound extending survival by greater than80% and showing activity against both mouse and hamster prions as well as efficacy upon intraperitoneal administration into mice. These results demonstrate the feasibility of targeted chemical design of compounds that may be useful for treating diseases of aberrant protein aggregation such as prion disease.
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| 3. |
- Keller, Annika, et al.
(författare)
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Mutations in the gene encoding PDGF-B cause brain calcifications in humans and mice
- 2013
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 45:9, s. 1077-
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Tidskriftsartikel (refereegranskat)abstract
- Calcifications in the basal ganglia are a common incidental finding and are sometimes inherited as an autosomal dominant trait ( idiopathic basal ganglia calcification (IBGC)). Recently, mutations in the PDGFRB gene coding for the platelet-derived growth factor receptor beta (PDGF-R beta) were linked to IBGC. Here we identify six families of different ancestry with nonsense and missense mutations in the gene encoding PDGF-B, the main ligand for PDGF-R beta. We also show that mice carrying hypomorphic Pdgfb alleles develop brain calcifications that show age-related expansion. The occurrence of these calcium depositions depends on the loss of endothelial PDGF-B and correlates with the degree of pericyte and blood-brain barrier deficiency. Thus, our data present a clear link between Pdgfb mutations and brain calcifications in mice, as well as between PDGFB mutations and IBGC in humans.
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| 4. |
- Kirschenbaum, Daniel, et al.
(författare)
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Whole-brain microscopy reveals distinct temporal and spatial efficacy of anti-A beta therapies
- 2023
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Ingår i: EMBO Molecular Medicine. - : WILEY. - 1757-4676 .- 1757-4684. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Many efforts targeting amyloid-beta (A beta) plaques for the treatment of Alzheimers Disease thus far have resulted in failures during clinical trials. Regional and temporal heterogeneity of efficacy and dependence on plaque maturity may have contributed to these disappointing outcomes. In this study, we mapped the regional and temporal specificity of various anti-A beta treatments through high-resolution light-sheet imaging of electrophoretically cleared brains. We assessed the effect on amyloid plaque formation and growth in Thy1-APP/PS1 mice subjected to beta-secretase inhibitors, polythiophenes, or anti-A beta antibodies. Each treatment showed unique spatiotemporal A beta clearance, with polythiophenes emerging as a potent anti-A beta compound. Furthermore, aligning with a spatial-transcriptomic atlas revealed transcripts that correlate with the efficacy of each A beta therapy. As observed in this study, there is a striking dependence of specific treatments on the location and maturity of A beta plaques. This may also contribute to the clinical trial failures of A beta-therapies, suggesting that combinatorial regimens may be significantly more effective in clearing amyloid deposition.
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| 5. |
- Margalith, Ilan, et al.
(författare)
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Polythiophenes Inhibit Prion Propagation by Stabilizing Prion Protein (PrP) Aggregates
- 2012
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Ingår i: Journal of Biological Chemistry. - : American Society for Biochemistry and Molecular Biology. - 0021-9258 .- 1083-351X. ; 287:23, s. 18872-18887
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Tidskriftsartikel (refereegranskat)abstract
- Luminescent conjugated polymers (LCPs) interact with ordered protein aggregates and sensitively detect amyloids of many different proteins, suggesting that they may possess antiprion properties. Here, we show that a variety of anionic, cationic, and zwitterionic LCPs reduced the infectivity of prion-containing brain homogenates and of prion-infected cerebellar organotypic cultured slices and decreased the amount of scrapie isoform of PrPC (PrPSc) oligomers that could be captured in an avidity assay. Paradoxically, treatment enhanced the resistance of PrPSc to proteolysis, triggered the compaction, and enhanced the resistance to proteolysis of recombinant mouse PrP(23-231) fibers. These results suggest that LCPs act as antiprion agents by transitioning PrP aggregates into structures with reduced frangibility. Moreover, ELISA on cerebellar organotypic cultured slices and in vitro conversion assays with mouse PrP(23-231) indicated that poly(thiophene-3-acetic acid) may additionally interfere with the generation of PrPSc by stabilizing the conformation of PrPC or of a transition intermediate. Therefore, LCPs represent a novel class of antiprion agents whose mode of action appears to rely on hyperstabilization, rather than destabilization, of PrPSc deposits.
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| 6. |
- Meisl, Georg, et al.
(författare)
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Scaling behaviour and rate-determining steps in filamentous self-assembly
- 2017
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Ingår i: Chemical Science. - : Royal Society of Chemistry (RSC). - 2041-6520 .- 2041-6539. ; 8:10, s. 7087-7097
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Tidskriftsartikel (refereegranskat)abstract
- The formation of filaments from naturally occurring protein molecules is a process at the core of a range of functional and aberrant biological phenomena, such as the assembly of the cytoskeleton or the appearance of aggregates in Alzheimer's disease. The macroscopic behaviour associated with such processes is remarkably diverse, ranging from simple nucleated growth to highly cooperative processes with a well-defined lagtime. Thus, conventionally, different molecular mechanisms have been used to explain the self-assembly of different proteins. Here we show that this range of behaviour can be quantitatively captured by a single unifying Petri net that describes filamentous growth in terms of aggregate number and aggregate mass concentrations. By considering general features associated with a particular network connectivity, we are able to establish directly the rate-determining steps of the overall aggregation reaction from the system's scaling behaviour. We illustrate the power of this framework on a range of different experimental and simulated aggregating systems. The approach is general and will be applicable to any future extensions of the reaction network of filamentous self-assembly.
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| 7. |
- Ni, Ruiqing, et al.
(författare)
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Multiscale optical and optoacoustic imaging of amyloid-beta deposits in mice
- 2022
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Ingår i: Nature Biomedical Engineering. - : NATURE PORTFOLIO. - 2157-846X. ; 6, s. 1031-1044
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Tidskriftsartikel (refereegranskat)abstract
- Large-field multifocal illumination fluorescence microscopy and panoramic volumetric multispectral optoacoustic tomography can be combined to longitudinally assess amyloid-beta deposits in transgenic mouse models of Alzheimers disease. Deposits of amyloid-beta (A beta) in the brains of rodents can be analysed by invasive intravital microscopy on a submillimetre scale, or via whole-brain images from modalities lacking the resolution or molecular specificity to accurately characterize A beta pathologies. Here we show that large-field multifocal illumination fluorescence microscopy and panoramic volumetric multispectral optoacoustic tomography can be combined to longitudinally assess A beta deposits in transgenic mouse models of Alzheimers disease. We used fluorescent A beta-targeted probes (the luminescent conjugated oligothiophene HS-169 and the oxazine-derivative AOI987) to transcranially detect A beta deposits in the cortex of APP/PS1 and arcA beta mice with single-plaque resolution (8 mu m) and across the whole brain (including the hippocampus and the thalamus, which are inaccessible by conventional intravital microscopy) at sub-150 mu m resolutions. Two-photon microscopy, light-sheet microscopy and immunohistochemistry of brain-tissue sections confirmed the specificity and regional distributions of the deposits. High-resolution multiscale optical and optoacoustic imaging of A beta deposits across the entire brain in rodents thus facilitates the in vivo study of A beta accumulation by brain region and by animal age and strain.
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| 8. |
- Nilsson, Peter, et al.
(författare)
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Structural typing of systemic amyloidoses by luminescent-conjugated polymer spectroscopy.
- 2010
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Ingår i: The American journal of pathology. - : Elsevier BV. - 1525-2191 .- 0002-9440. ; 176:2, s. 563-574
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Tidskriftsartikel (refereegranskat)abstract
- Most systemic amyloidoses are progressive and lethal, and their therapy depends on the identification of the offending proteins. Here we report that luminescent-conjugated thiophene polymers (LCP) sensitively detect amyloid deposits. The heterodisperse polythiophene acetic acid derivatives, polythiophene acetic acid (PTAA) and trimeric PTAA, emitted yellow-red fluorescence on binding to amyloid deposits, whereas chemically homogeneous pentameric formic thiophene acetic acid emitted green-yellow fluorescence. The geometry of LCPs modulates the spectral composition of the emitted light, thereby reporting ligand-induced steric changes. Accordingly, a screen of PTAA-stained amyloid deposits in histological tissue arrays revealed striking spectral differences between specimens. Blinded cluster assignments of spectral profiles of tissue samples from 108 tissue samples derived from 96 patients identified three nonoverlapping classes, which were found to match AA, AL, and ATTR immunotyping. We conclude that LCP spectroscopy is a sensitive and powerful tool for identifying and characterizing amyloid deposits.
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| 9. |
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| 10. |
- Ries, Jonas, et al.
(författare)
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Superresolution Imaging of Amyloid Fibrils with Binding-Activated Probes
- 2013
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Ingår i: ACS Chemical Neuroscience. - : American Chemical Society. - 1948-7193. ; 4:7, s. 1057-1061
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Tidskriftsartikel (refereegranskat)abstract
- Protein misfolding into amyloid-like aggregates underlies many neurodegenerative diseases. Thus, insights into the structure and function of these amyloids will provide valuable information on the pathological mechanisms involved and aid in the design of improved drugs for treating amyloid-based disorders. However, determining the structure of endogenous amyloids at high resolution has been difficult. Here we employ binding-activated localization microscopy (BALM) to acquire superresolution images of alpha-synuclein amyloid fibrils with unprecedented optical resolution. We propose that BALM imaging can be extended to study the structure of other amyloids, for differential diagnosis of amyloid-related diseases and for discovery of drugs that perturb amyloid structure for therapy.
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| 11. |
- Schuetz, Anne K., et al.
(författare)
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Binding of Polythiophenes to Amyloids : Structural Mapping of the Pharmacophore
- 2018
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Ingår i: ACS Chemical Neuroscience. - : American Chemical Society (ACS). - 1948-7193. ; 9:3, s. 475-481
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Tidskriftsartikel (refereegranskat)abstract
- Luminescent conjugated polythiophenes bind to amyloid proteins with high affinity. Their fluorescence properties, which are modulated by the detailed conformation in the bound state, are highly sensitive to structural features of the amyloid. Polythiophenes therefore represent diagnostic markers for the detection and differentiation of pathological amyloid aggregates. 560 We clarify the binding site and mode of two different polythiophenes to fibrils of the prion domain of the HET-s protein by solid-state NMR and correlate these findings with their fluorescence properties. We demonstrate how amyloid dyes recognize distinct binding sites with specific topological features. Regularly spaced surface charge patterns and well-accessible grooves on the fibril surface define the pharmacophore of the amyloid, which in turn determines the binding mode and fluorescence wavelength of the polythiophene.
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| 12. |
- Sigurdson, Christina J., et al.
(författare)
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A molecular switch controls interspeciesprion disease transmission in mice
- 2010
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Ingår i: Journal of Clinical Investigation. - : American Society for Clinical Investigation. - 0021-9738 .- 1558-8238. ; 120, s. 2590-2599
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Tidskriftsartikel (refereegranskat)abstract
- Transmissible spongiform encephalopathies are lethal neurodegenerative disorders that present with aggregated forms of the cellular prion protein (PrPC), which are known as PrPSc. Prions from different species vary considerably in their transmissibility to xenogeneic hosts. The variable transmission barriers depend on sequence differences between incoming PrPSc and host PrPC and additionally, on strain-dependent conformational properties of PrPSc. The β2-α2 loop region within PrPC varies substantially between species, with its structure being influenced by the residue types in the 2 amino acid sequence positions 170 (most commonly S or N) and 174 (N or T). In this study, we inoculated prions from 5 different species into transgenic mice expressing either disordered-loop or rigid-loop PrPC variants. Similar β2-α2 loop structures correlated with efficient transmission, whereas dissimilar loops correlated with strong transmission barriers. We then classified literature data on cross-species transmission according to the 170S/N polymorphism. Transmission barriers were generally low between species with the same amino acid residue in position 170 and high between those with different residues. These findings point to a triggering role of the local β2-α2 loop structure for prion transmissibility between different species.
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| 13. |
- Sigurdson, Christina J, et al.
(författare)
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De novo generation of a transmissible spongiform encephalopathy by mouse transgenesis.
- 2009
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 106:1, s. 304-309
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Tidskriftsartikel (refereegranskat)abstract
- Most transmissible spongiform encephalopathies arise either spontaneously or by infection. Mutations of PRNP, which encodes the prion protein, PrP, segregate with phenotypically similar diseases. Here we report that moderate overexpression in transgenic mice of mPrP(170N,174T), a mouse PrP with two point mutations that subtly affect the structure of its globular domain, causes a fully penetrant lethal spongiform encephalopathy with cerebral PrP plaques. This genetic disease was reproduced with 100% attack rate by intracerebral inoculation of brain homogenate to tga20 mice overexpressing WT PrP, and from the latter to WT mice, but not to PrP-deficient mice. Upon successive transmissions, the incubation periods decreased and PrP became more protease-resistant, indicating the presence of a strain barrier that was gradually overcome by repeated passaging. This shows that expression of a subtly altered prion protein, with known 3D structure, efficiently generates a prion disease.
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| 14. |
- Sigurdson, Christina J, et al.
(författare)
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Spongiform Encephalopathy in Transgenic Mice Expressing a Point Mutation in the beta 2-alpha 2 Loop of the Prion Protein
- 2011
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Ingår i: Journal of Neuroscience. - : Society for Neuroscience. - 0270-6474 .- 1529-2401. ; 31:39, s. 13840-13847
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Tidskriftsartikel (refereegranskat)abstract
- Transmissible spongiform encephalopathies are fatal neurodegenerative diseases attributed to misfolding of the cellular prion protein, PrP(C), into a beta-sheet-rich, aggregated isoform, PrP(Sc). We previously found that expression of mouse PrP with the two amino acid substitutions S170N and N174T, which result in high structural order of the beta 2-alpha 2 loop in the NMR structure at pH 4.5 and 20 C, caused transmissible de novo prion disease in transgenic mice. Here we report that expression of mouse PrP with the single-residue substitution D167S, which also results in a structurally well ordered beta 2-alpha 2 loop at 20 degrees C, elicits spontaneous PrP aggregation in vivo. Transgenic mice expressing PrP(D167S) developed a progressive encephalopathy characterized by abundant PrP plaque formation, spongiform change, and gliosis. These results add to the evidence that the beta 2-alpha 2 loop has an important role in intermolecular interactions, including that it may be a key determinant of prion protein aggregation.
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| 15. |
- Sponarova, Jana, et al.
(författare)
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Efficient Amyloid A Clearance in the Absence of Immunoglobulins and Complement Factors
- 2013
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Ingår i: American Journal of Pathology. - : Elsevier BV. - 0002-9440 .- 1525-2191. ; 182:4, s. 1297-1307
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Tidskriftsartikel (refereegranskat)abstract
- Amyloid A amyloidosis is a protein misfolding disease characterized by deposition of extracellular aggregates derived from the acute-phase reactant serum amyloid A protein. If untreated, amyloid A amyloidosis leads to irreversible damage of various organs, including the kidneys, liver, and heart. Amyloid A deposits regress upon reduction of serum amyloid A concentration, indicating that the amyloid can be efficiently cleared by natural mechanisms. Clearance was proposed to be mediated by humoral immune responses to amyloid. Here, we report that amyloid clearance in mice Lacking complement factors 3 and 4 (C3C4(-/-)) was equally efficient as in wild-type mice (C57BL/6), and was only slightly delayed in agammaglobulinemic mice (J(H-/-)). Hence, antibodies or complement factors are not necessary for natural amyloid clearance, implying the existence of alternative physiological pathways for amyloid removal.
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| 16. |
- Zarb, Yvette, et al.
(författare)
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Ossified blood vessels in primary familial brain calcification elicit a neurotoxic astrocyte response
- 2019
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Ingår i: Brain. - : OXFORD UNIV PRESS. - 0006-8950 .- 1460-2156. ; 142:4, s. 885-902
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Tidskriftsartikel (refereegranskat)abstract
- Brain calcifications are commonly detected in aged individuals and accompany numerous brain diseases, but their functional importance is not understood. In cases of primary familial brain calcification, an autosomally inherited neuropsychiatric disorder, the presence of bilateral brain calcifications in the absence of secondary causes of brain calcification is a diagnostic criterion. To date, mutations in five genes including solute carrier 20 member 2 (SLC20A2), xenotropic and polytropic retrovirus receptor 1 (XPR1), myogenesis regulating glycosidase (MYORG), platelet-derived growth factor B (PDGFB) and platelet-derived growth factor receptor beta (PDGFRB), are considered causal. Previously, we have reported that mutations in PDGFB in humans are associated with primary familial brain calcification, and mice hypomorphic for PDGFB (Pdgfb(ret/ret)) present with brain vessel calcifications in the deep regions of the brain that increase with age, mimicking the pathology observed in human mutation carriers. In this study, we characterize the cellular environment surrounding calcifications in Pdgfb(ret/ret) animals and show that cells around vessel-associated calcifications express markers for osteoblasts, osteoclasts and osteocytes, and that bone matrix proteins are present in vessel-associated calcifications. Additionally, we also demonstrate the osteogenic environment around brain calcifications in genetically confirmed primary familial brain calcification cases. We show that calcifications cause oxidative stress in astrocytes and evoke expression of neurotoxic astrocyte markers. Similar to previously reported human primary familial brain calcification cases, we describe high interindividual variation in calcification load in Pdgfb(ret/ret) animals, as assessed by ex vivo and in vivo quantification of calcifications. We also report that serum of Pdgfb(ret/ret) animals does not differ in calcification propensity from control animals and that vessel calcification occurs only in the brains of Pdgfb(ret/ret) animals. Notably, ossification of vessels and astrocytic neurotoxic response is associated with specific behavioural and cognitive alterations, some of which are associated with primary familial brain calcification in a subset of patients.
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| 17. |
- Åslund, Andreas, et al.
(författare)
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Novel Pentameric Thiophene Derivatives for in Vitro and in Vivo Optical Imaging of a Plethora of Protein Aggregates in Cerebral Amyloidoses
- 2009
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Ingår i: ACS CHEMICAL BIOLOGY. - : American Chemical Society (ACS). - 1554-8929 .- 1554-8937. ; 4:8, s. 673-684
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Tidskriftsartikel (refereegranskat)abstract
- Molecular probes for selective Identification of protein aggregates are important to advance our understanding of the molecular pathogenesis underlying cerebral amyloidoses. Here we report the chemical design of pentameric thiophene derivatives, denoted luminescent conjugated oligothiophenes (LCOs), which could be used for real-time visualization of cerebral protein aggregates in transgenic mouse models of neurodegenerative diseases by multiphoton microscopy. One of the LCOs, p-FTAA, could be utilized for ex vivo spectral assignment of distinct prion deposits from two, mouse-adapted prion strains. p-FTAA also revealed a transient soluble pre-fibrillar non-thioflavinophilic A beta-assemblies during in vitro fibrillation of A beta peptides. In brain tissue samples, A beta deposits and neurofibrillary tangles (NFTs) were readily identified by a strong fluorescence from p-FTAA and the LCO staining showed complete co-localliation with conventional antibodies (6E10 and AT8). In addition, a patchy islet-like staining of individual A beta plaque was unveiled by the anti-oligomer A11 antibody during co-staining with p-FTAA. The major hallmarks of Alzheimers disease, namely, A beta aggregates versus NFTs, could also be distinguished because of distinct emission spectra from p-FTAA. Overall, we demonstrate that LCOs can be utilized as powerful practical research tools for studying protein aggregation diseases and facilitate the study of amyloid origin, evolution and maturation, A beta-tau interactions, and pathogenesis both ex vivo and in vivo.
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