| 1. |
- Iashchishyn, Igor A., et al.
(author)
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Intranasally Administered S100A9 Amyloids Induced Cellular Stress, Amyloid Seeding, and Behavioral Impairment in Aged Mice
- 2018
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In: ACS Chemical Neuroscience. - : American Chemical Society (ACS). - 1948-7193. ; 9:6, s. 1338-1348
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Journal article (peer-reviewed)abstract
- Amyloid formation and neuroinflammation are major features of Alzheimer's disease pathology. Proinflammatory mediator S100A9 was shown to act as a link between the amyloid and neuroinflammatory cascades in Alzheimer's disease, leading together with Aβ to plaque formation, neuronal loss and memory impairment. In order to examine if S100A9 alone in its native and amyloid states can induce neuronal stress and memory impairment, we have administered S100A9 species intranasally to aged mice. Single and sequential immunohistochemistry and passive avoidance behavioral test were conducted to evaluate the consequences. Administered S100A9 species induced widespread cellular stress responses in cerebral structures, including frontal lobe, hippocampus and cerebellum. These were manifested by increased levels of S100A9, Box, and to a lesser extent activated caspase-3 immunopositive cells. Upon administration of S100A9 fibrils, the amyloid oligomerization was observed in the brain tissues, which can further exacerbate cellular stress. The cellular stress responses correlated with significantly increased training and decreased retention latencies measured in the passive avoidance test for the SI00A9 treated animal groups. Remarkably, the effect size in the behavioral tests was moderate already in the group treated with native S100A9, while the effect sizes were large in the groups administered S100A9 amyloid oligomers or fibrils. The findings demonstrate the brain susceptibility to neurotoxic damage of S100A9 species leading to behavioral and memory impairments. Intranasal administration of S100A9 species proved to be an effective method to study amyloid induced brain dysfunctions, and 5100A9 itself may be postulated as a target to allay early stage neurodegenerative and neuroinflammatory processes.
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| 2. |
- Minkevich, N. I., et al.
(author)
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Formation of amyloid-like fibrillar structures and destruction of fibroblasts of the Tenon's capsule in progressive myopia due to resistance of the pigment epithelium-derived factor to restricted proteolysis
- 2012
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In: Russian journal of bioorganic chemistry. - 1068-1620 .- 1608-330X. ; 38:6, s. 605-612
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Journal article (peer-reviewed)abstract
- We have previously shown that, normally, two forms of the pigment epithelium-derived factor (PEDF) with molecular weights of 50 and 45 kDa are present in the Tenon's capsule in equal amounts. These forms represent the full-length protein and a product of restricted proteolysis of PEDF. In persons with myopia, the full-length uncleaved factor was predominantly detected, which correlated with the disturbance of collagen fiber formation. An immunohistochemical study of the Tenon's capsule using polyclonal antibodies to PEDF showed that, in the control group, the factor is localized solely inside fibroblasts, whereas in patients with myopia, PEDF is distributed outside the cell as a halo around destroyed fibroblasts. It was shown in the present work using atomic force microscopy and immunodot assay with antibodies specific to amyloid fibrils that only the full-length PEDF is capable of forming amyloid-like fibrillar structures. The accumulation of fibrils leads to the destruction of fibroblasts and is a cause of changes in the biochemical composition and morphological structure of the Tenon's capsule in myopia.
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| 3. |
- Moskalenko, R. A., et al.
(author)
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Involvement of proinflammatory S100A9/A8 in the atherocalcinosis of aortic valves
- 2017
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In: Pathologia. - : Zaporizʹkyĭ derz͡havnyĭ medychnyĭ universytet. - 2306-8027. ; :1, s. 49-56
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Journal article (peer-reviewed)abstract
- According to the results of the Euro-Heart Survey on Vascular Heart Disease the most common pathology is nonrheumatic aortic stenosis, it is also called as calcific aortic valve stenosis (CAVS), as in its pathogenesis the process of biomineralization of valve cusps and ring plays the main role. The aim of the work is the immunohistochemical study of mineralized tissue of aortic heart valves, which are affected by atherocalcinosis. Materials and methods. 30 samples of mineralized aortic valves (I group) and 10 samples of aortic valve without evidence of biomineralization (II group - control) were studied. Immunohistochemical study of expression of collagen (Collagen I), CD68, myeloperoxidase (MPO), calgranulin A (S100A8), calgranulin B (8100A9), caspase 3 (Casp 3) and osteopontin (OPN) was conducted in AV tissue of both groups. Results. In CAV tissues the fibrillar component (collagen I) growths was found, but the quantitative and qualitative compositions of CD68+ circulating inflammatory cells are not significantly different from the control group. CAVs contain much more MPO+-cells (p <0.001) in comparison to the group of AVs without biomineralization. Our data show a significant increase of the S100A9 and OPN expression in the mineralized tissue of AVs (p <0.01). Also, a higher expression level of Casp3 and MPO was found in CAVs (p <0.05). Comparing the first and the second groups of AVs connection between the expression of S100A8 was not determined. Conclusion. High Casp 3 expression confirms the increased level of cell elimination in the CAVs tissue, which is obviously connected with the impact of high local concentrations of S100A9. These facts can contribute to the development of pathological biomineralization of AV. Since osteopontin inhibits the hydroxyapatite formation by binding to the surface of the crystals, its hyperproduction is a counteracting factor against biomineralization in AV tissue.
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| 4. |
- Chaudhary, Himanshu, et al.
(author)
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Polyoxometalates as Effective Nano-inhibitors of Amyloid Aggregation of Pro-inflammatory S100A9 Protein Involved in Neurodegenerative Diseases
- 2021
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In: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 13:23, s. 26721-26734
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Journal article (peer-reviewed)abstract
- Pro-inflammatory and amyloidogenic S100A9 protein is central to the amyloid-neuroinflammatory cascade in neurodegenerative diseases. Polyoxometalates (POMs) constitute a diverse group of nanomaterials, which showed potency in amyloid inhibition. Here, we have demonstrated that two selected nanosized niobium POMs, Nb10 and TiNb9, can act as potent inhibitors of S100A9 amyloid assembly. Kinetics analysis based on ThT fluorescence experiments showed that addition of either Nb10 or TiNb9 reduces the S100A9 amyloid formation rate and amyloid quantity. Atomic force microscopy imaging demonstrated the complete absence of long S100A9 amyloid fibrils at increasing concentrations of either POM and the presence of only round-shaped and slightly elongated aggregates. Molecular dynamics simulation revealed that both Nb10 and TiNb9 bind to native S100A9 homo-dimer by forming ionic interactions with the positively charged Lys residue-rich patches on the protein surface. The acrylamide quenching of intrinsic fluorescence showed that POM binding does not perturb the Trp 88 environment. The far and near UV circular dichroism revealed no large-scale perturbation of S100A9 secondary and tertiary structures upon POM binding. These indicate that POM binding involves only local conformational changes in the binding sites. By using intrinsic and 8-anilino-1-naphthalene sulfonate fluorescence titration experiments, we found that POMs bind to S100A9 with a Kd of ca. 2.5 μM. We suggest that the region, including Lys 50 to Lys 54 and characterized by high amyloid propensity, could be the key sequences involved in S1009 amyloid self-assembly. The inhibition and complete hindering of S100A9 amyloid pathways may be used in the therapeutic applications targeting the amyloid-neuroinflammatory cascade in neurodegenerative diseases.
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| 5. |
- Gruden, M. A., et al.
(author)
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Antibodies to Glutamate Reversed the Amnesic Effects of Proinflammatory S100A9 Protein Fibrils in Aged C57Bl/6 Mice
- 2017
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In: Bulletin of experimental biology and medicine. - : SPRINGER. - 0007-4888 .- 1573-8221. ; 162:4, s. 430-432
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Journal article (peer-reviewed)abstract
- Chronic intranasal administration of fibrillar structures of proinflammatory S100A9 protein impaired passive avoidance learning in old C57Bl/6 mice. Combined treatment with S100A9 fibrils and antibodies to glutamate was followed by an increase in horizontal locomotor activity of animals in the open-field test and did not disturb spatial memory.
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| 6. |
- Gruden, Marina A., et al.
(author)
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Immunoprotection against toxic biomarkers is retained during Parkinson's disease progression
- 2011
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In: Journal of Neuroimmunology. - : Elsevier. - 0165-5728 .- 1872-8421. ; 233:1-2, s. 221-227
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Journal article (peer-reviewed)abstract
- The aim was to ascertain any possible linkage between humoral immune responses to principal biomarkers (α-synuclein monomers, its toxic oligomers or fibrils, dopamine and S100B) and cellular immunity in Parkinson's disease development. There were elevated autoantibody titers to α-synuclein monomers, oligomers plus fibrils in 72%, 56%, and 17% of Parkinsonian patients respectively with a 5-year disease duration. Additionally, there were increased titers to dopamine and S100B (96% and 89%) in the 5-year patient group. All of these values subsided in 10-year sufferers. Furthermore, CD3+, CD4+, CD8+ T-lymphocyte and B-lymphocyte subsets declined in the patient cohort during Parkinsonism indicating disease associated reductions in these lymphocyte subsets.
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| 7. |
- Morozova-Roche, Ludmilla, et al.
(author)
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Fibrillation of Carrier Protein Albebetin and Its Biologically Active Constructs. Multiple Oligomeric Intermediates and Pathways
- 2004
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In: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 43:30, s. 9610-9619
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Journal article (peer-reviewed)abstract
- We showed that the genetically engineered carrier-protein albebetin and its biologically active constructs with interferon-2 octapeptide LKEKKYSP or differentiation factor hexapeptide TGENHR are inherently highly amyloidogenic at physiological pH. The kinetics of fibrillation were monitored by thioflavine-T (ThT) binding and the morphological changes by atomic force microscopy. Fibrillation proceeds via multiple pathways and includes a hierarchy of amyloid structures ranging from oligomers to protofilaments and fibrils. Comparative height and volume microscopic measurements allowed us to identify two distinct types of oligomeric intermediates: pivotal oligomers ca. 1.2 nm in height comprised of 10-12 monomers and on-pathway amyloid-competent oligomers ca. 2 nm in height constituted of 26-30 molecules. The former assemble into chains and rings with "bead-on-string morphology", in which a "bead" corresponds to an individual oligomer. Once formed, the rings and chains remain in solution simultaneously with fibrils. The latter give rise to protofilaments and fibrils, and their formation is concomitant with an increasing level of ThT binding. The amyloid nature of filamentous structures was confirmed by a pronounced ThT and Congo red binding and -sheet-rich far-UV circular dichroism. We suggest that transformation of the pivotal oligomers into the amyloid-prone ones is a limiting stage in amyloid assembly. Peptides, either fused to albebetin or added into solution, and an increased ionic strength promote fibrillation of albebetin (net charge of -12) by counterbalancing critical electrostatic repulsions. This finding demonstrates that the fibrillation of newly designed polypeptide-based products can produce multimeric amyloid species with a potentially "new" functionality, raising questions about their safety.
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| 8. |
- Wilhelm, Kristina R, 1976-, et al.
(author)
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Immune reactivity towards insulin, its amyloid and protein S100B in blood sera of Parkinson's disease patients
- 2007
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In: European Journal of Neurology. - : Wiley. - 1351-5101 .- 1468-1331. ; 14:3, s. 327-334
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Journal article (peer-reviewed)abstract
- Peripheral immune responses can be sensitive indicators of disease pathology. We evaluated the autoimmune reactions to endocrine (insulin) and astrocytical (S100B) biomarkers in the blood sera of 26 Parkinson's disease (PD) patients compared with controls by using ELISA. We found a statistically significant increase of the autoimmune responses to both antigens in PD patients compared with controls with a mean increase of 70% and 50% in the autoimmune reactions towards insulin and S100B, respectively. Heterogeneity of the immune responses observed in patients may reflect the modulating effect of multiple variables associated with neurodegeneration and also changes in the basic mechanisms of individual autoimmune reactivity. We did not detect any pronounced immune reactions towards insulin amyloid fibrils and oligomers in PD patients, indicating that an amyloid-specific conformational epitope is not involved in immune recognition of this amyloid type, while sequential epitope of native insulin is hidden within the amyloid structures. Immune reactions towards S100B and insulin may reflect the neurodegenerative brain damaging processes and impaired insulin homeostasis occurring in PD.
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| 9. |
- Åberg, Anna, et al.
(author)
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Helicobacter pylori adapts to chronic infection and gastric disease via ph-responsive baba-mediated adherence
- 2017
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In: Cell Host and Microbe. - : Elsevier BV. - 1931-3128 .- 1934-6069. ; 21:3, s. 376-389
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Journal article (peer-reviewed)abstract
- The BabA adhesin mediates high-affinity binding of Helicobacter pylori to the ABO blood group antigen-glycosylated gastric mucosa. Here we show that BabA is acid responsive-binding is reduced at low pH and restored by acid neutralization. Acid responsiveness differs among strains; often correlates with different intragastric regions and evolves during chronic infection and disease progression; and depends on pH sensor sequences in BabA and on pH reversible formation of high-affinity binding BabA multimers. We propose that BabA's extraordinary reversible acid responsiveness enables tight mucosal bacterial adherence while also allowing an effective escape from epithelial cells and mucus that are shed into the acidic bactericidal lumen and that bio-selection and changes in BabA binding properties through mutation and recombination with babA-related genes are selected by differences among individuals and by changes in gastric acidity over time. These processes generate diverse H. pylori subpopulations, in which BabA's adaptive evolution contributes to H. pylori persistence and overt gastric disease.
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| 10. |
- Blanch, Ewan W, et al.
(author)
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Is polyproline II helix the killer conformation? A Raman optical activity study of the amyloidogenic prefibrillar intermediate of human lysozyme.
- 2000
-
In: Journal of Molecular Biology. - : Elsevier BV. - 0022-2836 .- 1089-8638. ; 301:2, s. 553-563
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Journal article (peer-reviewed)abstract
- The amyloidogenic prefibrillar partially denatured intermediate of human lysozyme, prepared by heating the native protein to 57 degrees C at pH 2.0, was studied using Raman optical activity (ROA). A positive band in the room temperature ROA spectrum of the native protein at approximately 1345 cm(-1), assigned to a hydrated form of alpha-helix, is not present in that of the prefibrillar intermediate, where a new strong positive band at approximately 1318 cm(-1) appears instead that is assigned to the poly(l-proline) II (PPII)-helical conformation. A sharp negative band at approximately 1241 cm(-1) in the native protein, assigned to beta-strand, shows little change in the ROA spectrum of the prefibrillar intermediate. The disappearance of a positive ROA band at approximately 1551 cm(-1) assigned to vibrations of tryptophan side-chains indicates that major conformational changes have occurred among the five tryptophan residues present in human lysozyme, four of which are located in the alpha-domain. The various ROA data suggest that a substantial loss of tertiary structure has occurred in the prefibrillar intermediate and that this is located more in the alpha-domain than in the beta-domain. There is no evidence for any increase in beta-structure. The ROA spectrum of hen lysozyme, which does not form amyloid fibrils so readily, remains much more native-like on heating to 57 degrees C at pH 2.0. The thermal behaviour of the alanine-rich alpha-helical peptide AK21 in aqueous solution was found to be similar to that of human lysozyme. Hydrated alpha-helix therefore appears to readily undergo a conformational change to PPII structure on heating, which may be a key step in the conversion of alpha-helix into beta-sheet in the formation of amyloid fibrils in human lysozyme. Since it is extended, flexible, lacks intrachain hydrogen bonds and is fully hydrated in aqueous solution, PPII helix has the appropriate characteristics to be implicated as a critical conformational element in many conformational diseases. Disorder of the PPII type may be a sine qua non for the formation of regular fibrils; whereas the more dynamic disorder of the random coil may lead only to amorphous aggregates.
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| 11. |
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| 12. |
- Clementi, Emily A., et al.
(author)
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A Complex of Equine Lysozyme and Oleic Acid with Bactericidal Activity against Streptococcus pneumoniae
- 2013
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In: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 8:11, s. Article Number: UNSP e80649-
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Journal article (peer-reviewed)abstract
- HAMLET and ELOA are complexes consisting of oleic acid and two homologous, yet functionally different, proteins with cytotoxic activities against mammalian cells, with HAMLET showing higher tumor cells specificity, possibly due to the difference in propensity for oleic acid binding, as HAMLET binds 5-8 oleic acid molecules per protein molecule and ELOA binds 11-48 oleic acids. HAMLET has been shown to possess bactericidal activity against a number of bacterial species, particularly those with a respiratory tropism, with Streptococcus pneumoniae displaying the greatest degree of sensitivity. We show here that ELOA also displays bactericidal activity against pneumococci, which at lower concentrations shows mechanistic similarities to HAMLET's bactericidal activity. ELOA binds to S. pneumoniae and causes perturbations of the plasma membrane, including depolarization and subsequent rupture, and activates an influx of calcium into the cells. Selective inhibition of calcium channels and sodium/calcium exchange activity significantly diminished ELOA's bactericidal activity, similar to what we have observed with HAMLET. Finally, ELOA-induced death was also accompanied by DNA fragmentation into high molecular weight fragments - an apoptosis-like morphological phenotype that is seen during HAMLET-induced death. Thus, in contrast to different mechanisms of eukaryote cell death induced by ELOA and HAMLET, these complexes are characterized by rather similar activities towards bacteria. Although the majority of these events could be mimicked using oleic acid alone, the concentrations of oleic acid required were significantly higher than those present in the ELOA complex, and for some assays, the results were not identical between oleic acid alone and the ELOA complex. This indicates that the lipid, as a common denominator in both complexes, is an important component for the complexes' bactericidal activities, while the proteins are required both to solubilize and/or present the lipid at the bacterial membrane and likely to confer other and separate functions during the bacterial death.
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| 13. |
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| 14. |
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| 15. |
- Gruden, Marina A., et al.
(author)
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Correlation between Protective Immunity to alpha-Synuclein Aggregates, Oxidative Stress and Inflammation
- 2012
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In: Neuroimmunomodulation. - : S. Karger AG. - 1021-7401 .- 1423-0216. ; 19:6, s. 334-342
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Journal article (peer-reviewed)abstract
- Objective: Protein aggregation leading to central amyloid deposition is implicated in Parkinson's disease (PD). During disease progression, inflammation and oxidative stress may well invoke humoral immunity against pathological aggregates of PD-associated alpha-synuclein. The aim was to investigate any possible concurrence between autoimnnune responses to alpha-synuclein monomers, oligomers or fibrils with oxidative stress and inflammation.Methods: The formation of alpha-synuclein amyloid species was assessed by thioflavin-T assay and atomic force microscopy was employed to confirm their morphology. Serum autoantibody titers to alpha-synuclein conformations were determined by ELISA. Enzyme activity and concentrations of oxidative stress/inflammatory indicators were evaluated by enzyme and ELISA protocols.Results: In PD patient sera, a differential increase in autoantibody titers to alpha-synuclein monomers, toxic oligomers or fibrils was associated with boosted levels of the pro-inflammatory cytokine interleukin-6 and tumour necrosis factor-alpha, but a decrease in interferon-gamma concentration. In addition, levels of malondialdehyde were elevated whilst those of glutathione were reduced along with decrements in the activity of the antioxidants: superoxide dismutase, catalase and glutathione transferase.Conclusions: It is hypothesized that the generation of alpha-synuclein amyloid aggregates allied with oxidative stress and inflammatory reactions may invoke humoral immunity protecting against dopaminergic neuronal death. Hence, humoral immunity is a common integrative factor throughout PD progression which is directed towards prevention of further neurodegeneration, so potential treatment strategies should attempt to maintain PD patient immune status. Copyright (c) 2012 S. Karger AG, Basel
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| 16. |
- Gruden, Marina A, et al.
(author)
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Intranasal administration of alpha-synuclein aggregates : a Parkinson's disease model with behavioral and neurochemical correlates
- 2014
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In: Behavioural Brain Research. - : Elsevier. - 0166-4328 .- 1872-7549. ; 263, s. 158-168
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Journal article (peer-reviewed)abstract
- Parkinson's disease (PD) is a neurodegenerative disorder in which both alpha-synuclein (alpha-syn) and dopamine (DA) have a critical role. Our previous studies instigated a novel PD model based on nasal inoculation with alpha-syn aggregates which expressed parkinsonian-like behavioral and immunological features. The current study in mice substantiated the robustness of the amyloid nasal vector model by examining behavioral consequences with respect to DA-ergic neurochemical corollaries. In vitro generated alpha-syn oligomers and fibrils were characterized using atomic force microscopy and the thioflavin T binding assay. These toxic oligomers or fibrils administered alone (0.48 mg/kg) or their 50:50 combination (total dose of 0.48 mg/kg) were given intranasally for 14 days and "open-field" behavior was tested on days 0, 15 and 28 of the protocol. Behavioral deficits at the end of the 14-day dosing regime and on day 28 (i.e., 14 days after treatment completion) induced rigidity, hypokinesia and immobility. This was accompanied by elevated nigral but not striatal DA, DOPAC and HVA concentrations in response to dual administration of alpha-syn oligomers plus fibrils but not the oligomers by themselves. alpha-Syn fibrils intensified not only the hypokinesia and immobility 14 days post treatment, but also reduced vertical rearing and enhanced DA levels in the substantia nigra. Only nigral DA turnover (DOPAC/DA but not HVA/DA ratio) was augmented in response to fibril treatment but there were no changes in the striatum. Compilation of these novel behavioral and neurochemical findings substantiate the validity of the alpha-syn nasal vector model for investigating parkinsonian-like symptoms.(C) 2014 Elsevier B.V. All rights reserved.
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| 17. |
- Gruden, Marina A., et al.
(author)
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Nasal inoculation with a-synuclein aggregates evokes rigidity, locomotor deficits and immunity to such misfolded species as well as dopamine
- 2013
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In: Behavioural Brain Research. - : Elsevier BV. - 0166-4328 .- 1872-7549. ; 243, s. 205-212
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Journal article (peer-reviewed)abstract
- Animal models of Parkinson's disease (PD) have been widely used to investigate the pathogenesis of this neurodegenerative disorder which is typically associated with the specific and largely disordered protein alpha-synuclein (alpha-syn). In the current study, the nasal vector was used to deliver alpha-syn aggregates to the brain. Both alpha-syn oligomers and its fibrils were firstly characterized using atomic force microscopy and the thioflavin T binding assay. The toxic oligomers alone (0.48 mg/kg) or their 50:50 combination with fibrils (in a total dose of 0.48 mg/kg) were then given intranasally for ten days in mice and PD-mimetic symptoms as well as humoral immunity to these species and dopamine (DA) were evaluated simultaneously. Open-field behavioral deficits indicated by rigidity and reduced locomotor activity were induced by the dual administration of alpha-syn oligomers plus fibrils but not the oligomers by themselves under the 10-day dosing regimen. In contrast, using ELISA, high levels of serum autoantibodies to alpha-syn monomeric, oligomeric and fibrillar conformers as well as DA were observed in both treatment groups reflecting immune system activation and this substantiates previous clinical studies in Parkinson's disease patients. Thus, nasal administration of alpha-syn amyloidogenic species may be a potential experimental PD model which results not only in motor deficits but also incitement of humoral protection to mimic the disease. Such a paradigm may be exploitable in the quest for potential therapeutic strategies and further studies are warranted.
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| 18. |
- Gruden, Marina A, et al.
(author)
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Noradrenergic and serotonergic neurochemistry arising from intranasal inoculation with α-synuclein aggregates which incite parkinsonian-like symptoms
- 2015
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In: Behavioural Brain Research. - : Elsevier BV. - 0166-4328 .- 1872-7549. ; 279, s. 191-201
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Journal article (peer-reviewed)abstract
- Alpha-synuclein (α-syn) toxic aggregates delivered by the nasal vector have been shown to modify the neurochemistry of dopamine (DA) which is associated with parkinsonian-like motor symptoms. The aim was therefore to study the intranasal effects of α-syn oligomers, fibrils or their combination on the motor behavior of aged mice in relation to possible noradrenergic and serotonergic correlates. In vitro generated α-syn oligomers and fibrils were verified using atomic force microscopy and the thioflavin T binding assay. Levels of noradrenaline (NA), serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were detected using HPLC with electrochemical detection in the substantia nigra (SN) and striatum. The oligomers or fibrils administered alone or in a 50:50 combination (total dose of 0.48mg/kg) were given intranasally for 14 days and "open-field" behaviour was tested on days 0, 15 and 28 of the protocol, at which time brain structures were sampled. Behavioral deficits at the end of the 14-day dosing regime and on day 28 (i.e. 14 days after treatment completion) induced hypokinesia and immobility whilst the aggregate combination additionally produced rigidity. The α-Syn oligomer/fibril mixture also instigated PD-like motor symptoms which correlated heterochronically with elevated NA levels in the striatum but then later in the SN while intranasal fibrils alone augmented 5-HT and 5-HIAA nigral concentrations throughout the protocol. In contrast, α-syn oligomers displayed a delayed serotonin upsurge in the SN. Neurodegenerative and/or actions on neurotransmitter transporters (such as NET, SERT and VMAT2) are discussed as being implicated in these α-syn amyloid induced neurochemical and motoric disturbances.
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| 19. |
- Gruden, Marina A., et al.
(author)
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The misfolded pro-inflammatory protein S100A9 disrupts memory via neurochemical remodelling instigating an Alzheimer's disease-like cognitive deficit
- 2016
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In: Behavioural Brain Research. - : Elsevier BV. - 0166-4328 .- 1872-7549. ; 306, s. 106-116
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Journal article (peer-reviewed)abstract
- Memory deficits may develop from a variety of neuropathologies including Alzheimer's disease dementia. During neurodegenerative conditions there are contributory factors such as neuroinflammation and amyloidogenesis involved in memory impairment. In the present study, dual properties of S100A9 protein as a pro-inflammatory and amyloidogenic agent were explored in the passive avoidance memory task along with neurochemical assays in the prefrontal cortex and hippocampus of aged mice. S100A9 oligomers and fibrils were generated in vitro and verified by AFM, Thioflavin T and All antibody binding. Native S100A9 as well as S100A9 oligomers and fibrils or their combination were administered intranasally over 14 days followed by behavioral and neurochemical analysis. Both oligomers and fibrils evoked amnestic activity which correlated with disrupted prefrontal cortical and hippocampal dopaminergic neurochemistry. The oligomer-fibril combination produced similar but weaker neurochemistry to the fibrils administered alone but without passive avoidance amnesia. Native S100A9 did not modify memory task performance even though it generated a general and consistent decrease in monoamine levels (DA, 5-HT and NA) and increased metabolic marker ratios of DA and 5-HT turnover (DOPAC/DA, HVA/DA and 5-HIAA) in the prefrontal cortex. These results provide insight into a novel pathogenetic mechanism underlying amnesia in a fear-aggravated memory task based on amyloidogenesis of a pro-inflammatory factor leading to disrupted brain neurochemistry in the aged brain. The data further suggests that amyloid species of S100A9 create deleterious effects principally on the dopaminergic system and this novel finding might be potentially exploited during dementia management through a neuroprotective strategy.
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| 20. |
- Horvath, Istvan, et al.
(author)
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Immunochemical Detection of alpha-Synuclein Autoantibodies in Parkinson's Disease : Correlation between Plasma and Cerebrospinal Fluid Levels
- 2017
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In: ACS Chemical Neuroscience. - : American Chemical Society (ACS). - 1948-7193. ; 8:6, s. 1170-1176
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Journal article (peer-reviewed)abstract
- Autoantibodies to Parkinson's disease (PD) amyloidogenic protein, a-synuclein, were recognized as a prospective biomarker for early disease diagnostics, yet there is inconsistency in previous reports, potentially related to PD status. Therefore, plasma and cerebrospinal fluid (CSF) of the cross-sectional cohort of 60 individuals, including recently diagnosed PD patients with mild and moderate PD and age-matched controls, were examined by enzyme-linked immunosorbent assay (ELISA). Nonparametric statistics was used for data analysis. We found significantly elevated levels of a-synuclein autoantibodies in both plasma and CSF in mild PD compared to controls, followed by some decrease in moderate PD. Receiver operating characteristic and effect size analyses confirmed the diagnostic power of a-synuclein antibodies in both plasma and CSF. For the first time, we showed the correlation between plasma and CSF a-synuclein antibody levels for mild, moderate, and combined PD groups. This indicates the potentiality of a-synuclein antibodies as PD biomarker and the increased diagnostic power of their simultaneous analysis in plasma and CSF.
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| 21. |
- Iashchishyn, Igor A., et al.
(author)
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Finke-Watzky Two-Step Nucleation-Autocatalysis Model of S100A9 Amyloid Formation : Protein Misfolding as "Nucleation" Event
- 2017
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In: ACS Chemical Neuroscience. - : American Chemical Society (ACS). - 1948-7193. ; 8:10, s. 2152-2158
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Journal article (peer-reviewed)abstract
- Quantitative kinetic analysis is critical for understanding amyloid mechanisms. Here we demonstrate the application of generic Finke-Watzky (F-W) two-step nucleation-autocatalytic growth model to the concentration-dependent amyloid kinetics of proinflammatory alpha-helical S100A9 protein at pH 7.4 and at 37 and 42 degrees C. The model is based on two pseudoelementary reaction steps applied without further analytical constraints, and its treatment of S100A9 amyloid self-assembly demonstrates that initial misfolding and beta-sheet formation, defined as "nucleation" step, spontaneously takes place within individual S100A9 molecules at higher rate than the subsequent fibrillar growth. The latter, described as an autocatalytic process, will proceed if misfolded amyloid-prone S100A9 is populated on a macroscopic time scale. Short lengths of S100A9 fibrils are consistent with the F-W model. The analysis of fibrillar length distribution by the Beker-Doring model demonstrates independently that such distribution is solely determined by slow fibril growth and there is no fragmentation or secondary pathways decreasing fibrillar length.
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| 22. |
- Kaspersen, Jørn D., et al.
(author)
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Generic structures of cytotoxic liprotides : nano-sized complexes with oleic acid cores and shells of disordered proteins
- 2014
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In: ChemBioChem. - : Wiley-VCH Verlagsgesellschaft. - 1439-4227 .- 1439-7633. ; 15:18, s. 2693-2702
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Journal article (peer-reviewed)abstract
- The cytotoxic complex formed between alpha-lactalbumin and oleic acid (OA) has inspired many studies on protein-fatty acid complexes, but structural insight remains sparse. After having used small-angle X-ray scattering (SAXS) to obtain structural information, we present a new, generic structural model of cytotoxic protein-oleic acid complexes, which we have termed liprotides (lipids and partially denatured proteins). Twelve liprotides formed from seven structurally unrelated proteins and prepared by different procedures all displayed core-shell structures, each with a micellar OA core and a shell consisting of flexible, partially unfolded protein, which stabilizes the OA micelle. The common structure explains similar effects exerted on cells by different liprotides and is consistent with a cargo off-loading of the OA into cell membranes.
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| 23. |
- Morozova-Roche, Ludmilla A, et al.
(author)
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Independent nucleation and heterogeneous assembly of structure during folding of equine lysozyme
- 1999
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In: Journal of Molecular Biology. - : Elsevier BV. - 0022-2836 .- 1089-8638. ; 289:4, s. 1055-1073
-
Journal article (peer-reviewed)abstract
- The refolding of equine lysozyme from guanidinium chloride has been studied using hydrogen exchange pulse labelling in conjunction with NMR spectroscopy and stopped flow optical methods. The stopped flow optical experiments indicate that extensive hydrophobic collapse occurs rapidly after the initiation of refolding. Pulse labelling experiments monitoring nearly 50 sites within the protein have enabled the subsequent formation of native-like structure to be followed in considerable detail. They reveal that an intermediate having persistent structure within three of the four helices of the alpha-domain of the protein is formed for the whole population of molecules within 4 ms. Subsequent to this event, however, the hydrogen exchange protection kinetics are complex and highly heterogeneous. Analysis of the results by fitting to stretched exponential functions shows that a series of other intermediates is formed as a consequence of the stepwise assembly of independently nucleated local regions of structure. In some molecules the next step in folding involves the stabilisation of the remaining helix in the alpha-domain, whilst in others persistent structure begins to form in the beta-domain. The formation of native-like structure throughout the beta-domain is itself heterogeneous, involving at least three kinetically distinguishable steps. Residues in loop regions throughout the protein attain persistent structure more slowly than regions of secondary structure. There is in addition evidence for locally misfolded regions of structure that reorganise on much longer timescales. The results reveal that the native state of the protein is generated by the heterogeneous assembly of a series of locally cooperative regions of structure. This observation has many features in common with the findings of recent theoretical simulations of protein folding.
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| 24. |
- Pansieri, Jonathan, et al.
(author)
-
Templating S100A9 amyloids on Aβ fibrillar surfaces revealed by charge detection mass spectrometry, microscopy, kinetic and microfluidic analyses
- 2020
-
In: Chemical Science. - : Royal Society of Chemistry. - 2041-6520 .- 2041-6539. ; 11:27, s. 7031-7039
-
Journal article (peer-reviewed)abstract
- The mechanism of amyloid co-aggregation and its nucleation process are not fully understood in spite of extensive studies. Deciphering the interactions between proinflammatory S100A9 protein and Aβ42 peptide in Alzheimer's disease is fundamental since inflammation plays a central role in the disease onset. Here we use innovative charge detection mass spectrometry (CDMS) together with biophysical techniques to provide mechanistic insight into the co-aggregation process and differentiate amyloid complexes at a single particle level. Combination of mass and charge distributions of amyloids together with reconstruction of the differences between them and detailed microscopy reveals that co-aggregation involves templating of S100A9 fibrils on the surface of Aβ42 amyloids. Kinetic analysis further corroborates that the surfaces available for the Aβ42 secondary nucleation are diminished due to the coating by S100A9 amyloids, while the binding of S100A9 to Aβ42 fibrils is validated by a microfluidic assay. We demonstrate that synergy between CDMS, microscopy, kinetic and microfluidic analyses opens new directions in interdisciplinary research.
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| 25. |
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| 26. |
- Arabuli, Lili, et al.
(author)
-
Co-aggregation of S100A9 with DOPA and cyclen-based compounds manifested in amyloid fibril thickening without altering rates of self-assembly
- 2021
-
In: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 22:16
-
Journal article (peer-reviewed)abstract
- The amyloid cascade is central for the neurodegeneration disease pathology, including Alzheimer’s and Parkinson’s, and remains the focus of much current research. S100A9 protein drives the amyloid-neuroinflammatory cascade in these diseases. DOPA and cyclen-based compounds were used as amyloid modifiers and inhibitors previously, and DOPA is also used as a precursor of dopamine in Parkinson’s treatment. Here, by using fluorescence titration experiments we showed that five selected ligands: DOPA-D-H-DOPA, DOPA-H-H-DOPA, DOPA-D-H, DOPA-cyclen, and H-E-cyclen, bind to S100A9 with apparent Kd in the sub-micromolar range. Ligand docking and molecular dynamic simulation showed that all compounds bind to S100A9 in more than one binding site and with different ligand mobility and H-bonds involved in each site, which all together is consistent with the apparent binding determined in fluorescence experiments. By using amyloid kinetic analysis, monitored by thioflavin-T fluorescence, and AFM imaging, we found that S100A9 co-aggregation with these compounds does not hinder amyloid formation but leads to morphological changes in the amyloid fibrils, manifested in fibril thickening. Thicker fibrils were not observed upon fibrillation of S100A9 alone and may influence the amyloid tissue propagation and modulate S100A9 amyloid assembly as part of the amyloid-neuroinflammatory cascade in neurodegenerative diseases.
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| 27. |
- Baldassarre, Maurizio, et al.
(author)
-
Amyloid beta-peptides 1-40 and 1-42 form oligomers with mixed beta-sheets
- 2017
-
In: Chemical Science. - : Royal Society of Chemistry (RSC). - 2041-6520 .- 2041-6539. ; 8:12, s. 8247-8254
-
Journal article (peer-reviewed)abstract
- Two main amyloid-beta peptides of different length (A beta(40) and A beta(42)) are involved in Alzheimer's disease. Their relative abundance is decisive for the severity of the disease and mixed oligomers may contribute to the toxic species. However, little is know about the extent of mixing. To study whether A beta(40) and A beta(42) co-aggregate, we used Fourier transform infrared spectroscopy in combination with C-13-labeling and spectrum calculation and focused on the amide I vibration, which is sensitive to backbone structure. Mixtures of monomeric labeled A beta(40) and unlabeled A beta(42) (and vice versa) were co-incubated for similar to 20 min and their infrared spectrum recorded. The position of the main C-13-amide I' band shifted to higher wavenumbers with increasing admixture of C-12-peptide due to the presence of C-12-amides in the vicinity of C-13-amides. The results indicate that A beta(40) and A beta(42) form mixed oligomers with a largely random distribution of A beta(40) and A beta(42) strands in their beta-sheets. The structures of the mixed oligomers are intermediate between those of the pure oligomers. There is no indication that one of the peptides forces the backbone structure of its oligomers on the other peptide when they are mixed as monomers. We also demonstrate that isotope-edited infrared spectroscopy can distinguish aggregation modulators that integrate into the backbone structure of their interaction partner from those that do not. As an example for the latter case, the pro-inflammatory calcium binding protein S100A9 is shown not to incorporate into the b-sheets of A beta(42).
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| 28. |
- Baumann, Anne, et al.
(author)
-
Tyrosine Hydroxylase Binding to Phospholipid Membranes Prompts Its Amyloid Aggregation and Compromises Bilayer Integrity
- 2016
-
In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
-
Journal article (peer-reviewed)abstract
- Tyrosine hydroxylase (TH), a rate-limiting enzyme in the synthesis of catecholamine neurotransmitters and hormones, binds to negatively charged phospholipid membranes. Binding to both large and giant unilamellar vesicles causes membrane permeabilization, as observed by efflux and influx of fluorescence dyes. Whereas the initial protein-membrane interaction involves the N-terminal tail that constitutes an extension of the regulatory ACT-domain, prolonged membrane binding induces misfolding and self-oligomerization of TH over time as shown by circular dichroism and Thioflavin T fluorescence. The gradual amyloid-like aggregation likely occurs through cross-beta interactions involving aggregation-prone motives in the catalytic domains, consistent with the formation of chain and ring-like protofilaments observed by atomic force microscopy in monolayer-bound TH. PC12 cells treated with the neurotoxin 6-hydroxydopamine displayed increased TH levels in the mitochondrial fraction, while incubation of isolated mitochondria with TH led to a decrease in the mitochondrial membrane potential. Furthermore, cell-substrate impedance and viability assays showed that supplementing the culture media with TH compromises cell viability over time. Our results revealed that the disruptive effect of TH on cell membranes may be a cytotoxic and pathogenic factor if the regulation and intracellular stability of TH is compromised.
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| 29. |
- Blanch, Ewan W, et al.
(author)
-
Raman optical activity characterization of native and molten globule states of equine lysozyme : comparison with hen lysozyme and bovine alpha-lactalbumin
- 2000
-
In: Biopolymers. - 0006-3525 .- 1097-0282. ; 57:4, s. 235-248
-
Journal article (peer-reviewed)abstract
- Vibrational Raman optical activity (ROA) spectra of the calcium-binding lysozyme from equine milk in native and nonnative states are measured and compared with those of the homologous proteins hen egg white lysozyme and bovine alpha-lactalbumin. The ROA spectrum of holo equine lysozyme at pH 4.6 and 22 degrees C closely resembles that of hen lysozyme in regions sensitive to backbone and side chain conformations, indicating similarity of the overall secondary and tertiary structures. However, the intensity of a strong positive ROA band at approximately 1340 cm(-1), which is assigned to a hydrated form of alpha helix, is more similar to that in the ROA spectrum of bovine alpha-lactalbumin than hen lysozyme and may be associated with the greater flexibility and calcium-binding ability of equine lysozyme and bovine alpha-lactalbumin compared with hen lysozyme. In place of a strong sharp positive ROA band at approximately 1300 cm(-1) in hen lysozyme that is assigned to an alpha helix in a more hydrophobic environment, equine lysozyme shows a broader band centered at approximately 1305 cm(-1), which may reflect greater heterogeneity in some alpha-helical sequences. The ROA spectrum of apo equine lysozyme at pH 4.6 and 22 degrees C is almost identical to that of the holo protein, which indicates that loss of calcium has little influence on the backbone and side chain conformations, including the calcium-binding loop. From the similarity of their ROA spectra, the A state at pH 1.9 and both 2 and 22 degrees C and the apo form at pH 4.5 and 48 degrees C, which are partially folded denatured (molten globule or state A) forms of equine lysozyme, have similar structures that the ROA suggests contain much hydrated alpha helix. The A state of equine lysozyme is shown by these results to be more highly ordered than that of bovine alpha-lactalbumin, the ROA spectrum of which has more features characteristic of disordered states. A positive tryptophan ROA band at approximately 1551 cm(-1) in the native holo protein disappears in the A state, which is probably due to the presence of nonnative conformations of the tryptophans associated with a previously identified cluster of hydrophobic residues.
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| 30. |
- Botelho, Hugo M., et al.
(author)
-
S100A6 Amyloid Fibril formation is Calcium-modulated and enhances Superoxide Dismutase-1 (SOD1) aggregation
- 2012
-
In: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 287:50, s. 42233-42242
-
Journal article (peer-reviewed)abstract
- S100A6 is a small EF-hand calcium- and zinc-binding protein involved in the regulation of cell proliferation and cytoskeletal dynamics. It is overexpressed in neurodegenerative disorders and a proposed marker for Amyotrophic Lateral Sclerosis (ALS). Following recent reports of amyloid formation by S100 proteins, we investigated the aggregation properties of S100A6. Computational analysis using aggregation predictors Waltz and Zyggregator revealed increased propensity within S100A6 helices HI and HIV. Subsequent analysis of Thioflavin-T binding kinetics under acidic conditions elicited a very fast process with no lag phase and extensive formation of aggregates and stacked fibrils as observed by electron microscopy. Ca2+ exerted an inhibitory effect on the aggregation kinetics, which could be reverted upon chelation. An FT-IR investigation of the early conformational changes occurring under these conditions showed that Ca2+ promotes anti-parallel beta-sheet conformations that repress fibrillation. At pH 7, Ca2+ rendered the fibril formation kinetics slower: time-resolved imaging showed that fibril formation is highly suppressed, with aggregates forming instead. In the absence of metals an extensive network of fibrils is formed. S100A6 oligomers, but not fibrils, were found to be cytotoxic, decreasing cell viability by up to 40%. This effect was not observed when the aggregates were formed in the presence of Ca2+. Interestingly, native S1006 seeds SOD1 aggregation, shortening its nucleation process. This suggests a cross-talk between these two proteins involved in ALS. Overall, these results put forward novel roles for S100 proteins, whose metalmodulated aggregation propensity may be a key aspect in their physiology and function.
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| 31. |
- Bryan, Thomas, et al.
(author)
-
The robust electrochemical detection of a Parkinson's disease marker in whole blood sera
- 2012
-
In: Chemical Science. - : Royal Society of Chemistry (RSC). - 2041-6520 .- 2041-6539. ; 3:12, s. 3468-3473
-
Journal article (peer-reviewed)abstract
- Protein aggregation, leading to amyloid deposition in the brain, is implicated in the pathology of a number of increasingly prevalent neurodegeneration states such as Parkinson's disease (PD), Alzheimer's disease and prion diseases. The body's protective response to the formation of such deposits is to generate specific autoimmune antibodies. Alpha-synuclein, a natively unfolded protein relatively abundant in the brain, is the main constituent of Lewy body amyloid dispositions in PD. Previous assays determining content of alpha-synuclein in bodily fluids have proven to be largely inconclusive. Here we have taken a novel approach in utilising alpha-synuclein modified electrodes to sample the autoantibodies generated as the body responds to changes in its homeostasis. We show that these electroanalytical assays not only robustly distinguish between disease state and control individuals but also map out disease progression with unprecedented sensitivity and clarity. The impedimetric electrode surfaces are highly specific, reusable, exhibit a linear range from 0.5 to 10 nM and a detection limit of 55 +/- 3 pM. We believe electroanalyses such as these, possible with less than 10 microlitres of fluid and a total assay time of only a few minutes, to be of value for early diagnosis of PD and possibly other alpha-synucleinopathies, and for monitoring disease progression and effects of possible disease modifying interventions.
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| 32. |
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| 33. |
- Casaite, Vida, et al.
(author)
-
Expression and purification of active recombinant equine lysozyme in Escherichia coli
- 2009
-
In: Protein Engineering Design & Selection. - : Oxford University Press (OUP). - 1741-0126 .- 1741-0134. ; 22:11, s. 649-654
-
Journal article (peer-reviewed)abstract
- Equine lysozyme (EL) is a calcium (Ca)-binding lysozyme and is an intermediary link between non-Ca-binding C-type lysozyme and alpha-lactalbumin. The feature of lysozymes to assemble into the fibrils has recently gained considerable attention for the investigation of the functional properties of these proteins. To study the structural and functional properties of EL, a synthetic gene was cloned and EL was overexpressed in Escherichia coli as a fused protein. The His-tagged recombinant EL was accumulated as inclusion bodies. Up to 50 mg/l of the recombinant EL could be achieved after purification by Ni(2+) affinity chromatography, refolding in the presence of arginine, CM-Sepharose column purification following TEV protease cleavage. The purified protein was functionally active, as determined by the lysozyme activity, proving the proper folding of protein. The purified lysozyme was used for the oligomerisation studies. The protein formed amyloid fibrils during incubation in acidic pH and elevated temperature. The recombinant EL forms two types of fibrils: ring shaped and linear, similar to the native EL.
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| 34. |
- Chamberlain, Aaron K, et al.
(author)
-
Ultrastructural organization of amyloid fibrils by atomic force microscopy
- 2000
-
In: Biophysical Journal. - : Cell Press. - 0006-3495 .- 1542-0086. ; 79:6, s. 3282-3293
-
Journal article (peer-reviewed)abstract
- Atomic force microscopy has been employed to investigate the structural organization of amyloid fibrils produced in vitro from three very different polypeptide sequences. The systems investigated are a 10-residue peptide derived from the sequence of transthyretin, the 90-residue SH3 domain of bovine phosphatidylinositol-3'-kinase, and human wild-type lysozyme, a 130-residue protein containing four disulfide bridges. The results demonstrate distinct similarities between the structures formed by the different classes of fibrils despite the contrasting nature of the polypeptide species involved. SH3 and lysozyme fibrils consist typically of four protofilaments, exhibiting a left-handed twist along the fibril axis. The substructure of TTR(10-19) fibrils is not resolved by atomic force microscopy and their uniform appearance is suggestive of a regular self-association of very thin filaments. We propose that the exact number and orientation of protofilaments within amyloid fibrils is dictated by packing of the regions of the polypeptide chains that are not directly involved in formation of the cross-beta core of the fibrils. The results obtained for these proteins, none of which is directly associated with any human disease, are closely similar to those of disease-related amyloid fibrils, supporting the concept that amyloid is a generic structure of polypeptide chains. The detailed architecture of an individual fibril, however, depends on the manner in which the protofilaments assemble into the fibrillar structure, which in turn is dependent on the sequence of the polypeptide and the conditions under which the fibril is formed.
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| 35. |
- Eremenko, Ekaterina, et al.
(author)
-
Aggregation of Human S100A8 and S100A9 Amyloidogenic Proteins Perturbs Proteostasis in a Yeast Model
- 2013
-
In: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 8:3, s. e58218-
-
Journal article (peer-reviewed)abstract
- Amyloid aggregates of the calcium-binding EF-hand proteins, S100A8 and S100A9, have been found in the corpora amylacea of patients with prostate cancer and may play a role in carcinogenesis. Here we present a novel model system using the yeast Saccharomyces cerevisiae to study human S100A8 and S100A9 aggregation and toxicity. We found that S100A8, S100A9 and S100A8/9 cotransfomants form SDS-resistant non-toxic aggregates in yeast cells. Using fluorescently tagged proteins, we showed that S100A8 and S100A9 accumulate in foci. After prolonged induction, S100A8 foci localized to the cell vacuole, whereas the S100A9 foci remained in the cytoplasm when present alone, but entered the vacuole in cotransformants. Biochemical analysis of the proteins indicated that S100A8 and S100A9 alone or coexpressed together form amyloid-like aggregates in yeast. Expression of S100A8 and S100A9 in wild type yeast did not affect cell viability, but these proteins were toxic when expressed on a background of unrelated metastable temperature-sensitive mutant proteins, Cdc53-1p, Cdc34-2p, Srp1-31p and Sec27-1p. This finding suggests that the expression and aggregation of S100A8 and S100A9 may limit the capacity of the cellular proteostasis machinery. To test this hypothesis, we screened a set of chaperone deletion mutants and found that reducing the levels of the heat-shock proteins Hsp104p and Hsp70p was sufficient to induce S100A8 and S100A9 toxicity. This result indicates that the chaperone activity of the Hsp104/Hsp70 bi-chaperone system in wild type cells is sufficient to reduce S100A8 and S100A9 amyloid toxicity and preserve cellular proteostasis. Expression of human S100A8 and S100A9 in yeast thus provides a novel model system for the study of the interaction of amyloid deposits with the proteostasis machinery.
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| 36. |
- Fritz, Günter, et al.
(author)
-
Natural and amyloid self-assembly of S100 proteins : structural basis of functional diversity
- 2010
-
In: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 277:22, s. 4578-4590
-
Journal article (peer-reviewed)abstract
- The S100 proteins are 10-12 kDa EF-hand proteins that act as central regulators in a multitude of cellular processes including cell survival, proliferation, differentiation and motility. Consequently, many S100 proteins are implicated and display marked changes in their expression levels in many types of cancer, neurodegenerative disorders, inflammatory and autoimmune diseases. The structure and function of S100 proteins are modulated by metal ions via Ca(2+) binding through EF-hand motifs and binding of Zn(2+) and Cu(2+) at additional sites, usually at the homodimer interfaces. Ca(2+) binding modulates S100 conformational opening and thus promotes and affects the interaction with p53, the receptor for advanced glycation endproducts and Toll-like receptor 4, among many others. Structural plasticity also occurs at the quaternary level, where several S100 proteins self-assemble into multiple oligomeric states, many being functionally relevant. Recently, we have found that the S100A8/A9 proteins are involved in amyloidogenic processes in corpora amylacea of prostate cancer patients, and undergo metal-mediated amyloid oligomerization and fibrillation in vitro. Here we review the unique chemical and structural properties of S100 proteins that underlie the conformational changes resulting in their oligomerization upon metal ion binding and ultimately in functional control. The possibility that S100 proteins have intrinsic amyloid-forming capacity is also addressed, as well as the hypothesis that amyloid self-assemblies may, under particular physiological conditions, affect the S100 functions within the cellular milieu.
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| 37. |
- Goldberg, Emily L., et al.
(author)
-
beta-Hydroxybutyrate deactivates Neutrophil NLRP3 inflammasome to relieve gout flares
- 2017
-
In: Cell Reports. - : Elsevier BV. - 2211-1247. ; 18:9, s. 2077-2087
-
Journal article (peer-reviewed)abstract
- Aging and lipotoxicity are two major risk factors for gout that are linked by the activation of the NLRP3 inflammasome. Neutrophil-mediated production of interleukin-1 beta (IL-1 beta) drives gouty flares that cause joint destruction, intense pain, and fever. However, metabolites that impact neutrophil inflammasome remain unknown. Here, we identified that ketogenic diet (KD) increases beta-hydroxybutyrate (BHB) and alleviates urate crystal-induced gout without impairing immune defense against bacterial infection. BHB inhibited NLRP3 inflammasome in S100A9 fibril-primed and urate crystal-activated macrophages, which serve to recruit inflammatory neutrophils in joints. Consistent with reduced gouty flares in rats fed a ketogenic diet, BHB blocked IL-1 beta in neutrophils in a NLRP3-dependent manner in mice and humans irrespective of age. Mechanistically, BHB inhibited the NLRP3 inflammasome in neutrophils by reducing priming and assembly steps. Collectively, our studies show that BHB, a known alternate metabolic fuel, is also an anti-inflammatory molecule that may serve as a treatment for gout.
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| 38. |
- Gruden, Marina A., et al.
(author)
-
S100A9 Protein Aggregates Boost Hippocampal Glutamate Modifying Monoaminergic Neurochemistry : A Glutamate Antibody Sensitive Outcome on Alzheimer-like Memory Decline
- 2018
-
In: ACS Chemical Neuroscience. - : American Chemical Society (ACS). - 1948-7193. ; 9:3, s. 568-577
-
Journal article (peer-reviewed)abstract
- Alzheimer's disease (AD) involves dementia conceivably arising from integrated inflammatory processes, amyloidogenesis, and neuronal apoptosis. Glutamate can also cause neuronal death via excitotoxicity, and this is similarly implicated in some neurological diseases. The aim was to examine treatment with in vitro generated proinflammatory protein S100A9 aggregate species alone or with glutamate antibodies (Glu-Abs) on Morris water maze (MWM) spatial learning and memory performance in 12 month old mice. Amino acid and monoamine cerebral neurotransmitter metabolic changes were concurrently monitored. Initially, S100A9 fibrils were morphologically verified by atomic force microscopy and Thioflavin T assay. They were then administered intranasally alone or with Glu-Abs for 14 days followed by a 5 day MWM protocol before hippocampal and prefrontal cortical neurochemical analysis. S100A9 aggregates evoked spatial amnesia which correlated with disrupted glutamate and dopaminergic neurochemistry. Hippocampal glutamate release, elevation of DOPAC and HVA, as well as DOPAC/DA and HVA/DA ratios were subsequently reduced by Glu-Abs which simultaneously prevented the spatial memory deficit. The present outcomes emphasized the pathogenic nature of S100A9 fibrillar aggregates in causing spatial memory amnesia associated with enhanced hippocampal glutamate release and DA-ergic disruption in the aging brain. This finding might be exploited during dementia management through a neuroprotective strategy.
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| 39. |
- Horvath, Istvan, et al.
(author)
-
Co-aggregation of pro-inflammatory S100A9 with alpha-synuclein in Parkinson's disease : ex vivo and in vitro studies
- 2018
-
In: Journal of Neuroinflammation. - : Springer Science and Business Media LLC. - 1742-2094. ; 15
-
Journal article (peer-reviewed)abstract
- Background: Chronic neuroinflammation is a hallmark of Parkinson's disease (PD) pathophysiology, associated with increased levels of pro-inflammatory factors in PD brain tissues. The pro-inflammatory mediator and highly amyloidogenic protein S100A9 is involved in the amyloid-neuroinflammatory cascade in Alzheimer's disease. This is the first report on the co-aggregation of alpha-synuclein (alpha-syn) and S100A9 both in vitro and ex vivo in PD brain. Methods: Single and sequential immunohistochemistry, immunofluorescence, scanning electron and atomic force (AFM) microscopies were used to analyze the ex vivo PD brain tissues for S100A9 and alpha-syn location and aggregation. In vitro studies revealing S100A9 and alpha-syn interaction and co-aggregation were conducted by NMR, circular dichroism, Thioflavin-T fluorescence, AFM, and surface plasmon resonance methods. Results: Co-localized and co-aggregated S100A9 and alpha-syn were found in 20% Lewy bodies and 77% neuronal cells in the substantia nigra; both proteins were also observed in Lewy bodies in PD frontal lobe (Braak stages 4-6). Lewy bodies were characterized by ca. 10-23 mu m outer diameter, with S100A9 and alpha-syn being co-localized in the same lamellar structures. S100A9 was also detected in neurons and blood vessels of the aged patients without PD, but in much lesser extent. In vitro S100A9 and alpha-syn were shown to interact with each other via the alpha-syn C-terminus with an apparent dissociation constant of ca. 5 mu M. Their co-aggregation occurred significantly faster and led to formation of larger amyloid aggregates than the self-assembly of individual proteins. S100A9 amyloid oligomers were more toxic than those of alpha-syn, while co-aggregation of both proteins mitigated the cytotoxicity of S100A9 oligomers. Conclusions: We suggest that sustained neuroinflammation promoting the spread of amyloidogenic S100A9 in the brain tissues may trigger the amyloid cascade involving alpha-syn and S100A9 and leading to PD, similar to the effect of S100A9 and A beta co-aggregation in Alzheimer's disease. The finding of S100A9 involvement in PD may open a new avenue for therapeutic interventions targeting S100A9 and preventing its amyloid self-assembly in affected brain tissues.
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| 40. |
- Horvath, Istvan, et al.
(author)
-
Pro-inflammatory S100A9 Protein as a Robust Biomarker Differentiating Early Stages of Cognitive Impairment in Alzheimer's Disease
- 2016
-
In: ACS Chemical Neuroscience. - : American Chemical Society (ACS). - 1948-7193. ; 7:1, s. 34-39
-
Journal article (peer-reviewed)abstract
- Pro-inflammatory protein S100A9 was established as a biomarker of dementia progression and compared with others such as Aβ1-42 and tau-proteins. CSF samples from 104 stringently diagnosed individuals divided into five subgroups were analyzed, including nondemented controls, stable mild cognitive impairment (SMCI), mild cognitive impairment due to Alzheimer's disease (MCI-AD), Alzheimer's disease (AD), and vascular dementia (VaD) patients. ELISA, dot-blotting, and electrochemical impedance spectroscopy were used as research methods. The S100A9 and Aβ1-42 levels correlated with each other: their CSF content decreased already at the SMCI stage and declined further under MCI-AD, AD, and VaD conditions. Immunohistochemical analysis also revealed involvement of both Aβ1-42 and S100A9 in the amyloid-neuroinflammatory cascade already during SMCI. Tau proteins were not yet altered in SMCI; however their contents increased during MCI-AD and AD, diagnosing later dementia stages. Thus, four biomarkers together, reflecting different underlying pathological causes, can accurately differentiate dementia progression and also distinguish AD from VaD.
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| 41. |
- Jakubec, Martin, et al.
(author)
-
Cholesterol-containing lipid nanodiscs promote an α-synuclein binding mode that accelerates oligomerization
- 2021
-
In: The FEBS Journal. - : John Wiley & Sons. - 1742-464X .- 1742-4658. ; 288:6, s. 1887-1905
-
Journal article (peer-reviewed)abstract
- Dysregulation of the biosynthesis of cholesterol and other lipids has been implicated in many neurological diseases, including Parkinson's disease. Misfolding of α‐synuclein (α‐Syn), the main actor in Parkinson's disease, is associated with changes in a lipid environment. However, the exact molecular mechanisms underlying cholesterol effect on α‐Syn binding to lipids as well as α‐Syn oligomerization and fibrillation remain elusive, as does the relative importance of cholesterol compared to other factors. We probed the interactions and fibrillation behaviour of α‐Syn using styrene–maleic acid nanodiscs, containing zwitterionic and anionic lipid model systems with and without cholesterol. Surface plasmon resonance and thioflavin T fluorescence assays were employed to monitor α‐Syn binding, as well as fibrillation in the absence and presence of membrane models. 1H‐15N‐correlated NMR was used to monitor the fold of α‐Syn in response to nanodisc binding, determining individual residue apparent affinities for the nanodisc‐contained bilayers. The addition of cholesterol inhibited α‐Syn interaction with lipid bilayers and, however, significantly promoted α‐Syn fibrillation, with a more than a 20‐fold reduction of lag times before fibrillation onset. When α‐Syn bilayer interactions were analysed at an individual residue level by solution‐state NMR, we observed two different effects of cholesterol. In nanodiscs made of DOPC, the addition of cholesterol modulated the NAC part of α‐Syn, leading to stronger interaction of this region with the lipid bilayer. In contrast, in the nanodiscs comprising DOPC, DOPE and DOPG, the NAC part was mostly unaffected by the presence of cholesterol, while the binding of the N and the C termini was both inhibited.
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| 42. |
- Jia, Xueen, et al.
(author)
-
Neuroprotective and nootropic drug noopept rescues α-synuclein amyloid cytotoxicity
- 2011
-
In: Journal of Molecular Biology. - : Elsevier BV. - 0022-2836 .- 1089-8638. ; 414:5, s. 699-712
-
Journal article (peer-reviewed)abstract
- Parkinson's disease is a common neurodegenerative disorder characterized by α-synuclein (α-Syn)-containing Lewy body formation and selective loss of dopaminergic neurons in the substantia nigra. We have demonstrated the modulating effect of noopept, a novel proline-containing dipeptide drug with nootropic and neuroprotective properties, on α-Syn oligomerization and fibrillation by using thioflavin T fluorescence, far-UV CD, and atomic force microscopy techniques. Noopept does not bind to a sterically specific site in the α-Syn molecule as revealed by heteronuclear two-dimensional NMR analysis, but due to hydrophobic interactions with toxic amyloid oligomers, it prompts their rapid sequestration into larger fibrillar amyloid aggregates. Consequently, this process rescues the cytotoxic effect of amyloid oligomers on neuroblastoma SH-SY5Y cells as demonstrated by using cell viability assays and fluorescent staining of apoptotic and necrotic cells and by assessing the level of intracellular oxidative stress. The mitigating effect of noopept against amyloid oligomeric cytotoxicity may offer additional benefits to the already well-established therapeutic functions of this new pharmaceutical.
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| 43. |
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| 44. |
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| 45. |
- Minkevich, Natalya I., et al.
(author)
-
Abnormal pigment epithelium-derived factor processing in progressive myopia
- 2016
-
In: Experimental Eye Research. - : Elsevier BV. - 0014-4835 .- 1096-0007. ; 152, s. 1-9
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Journal article (peer-reviewed)abstract
- Pigment Epithelium-Derived Factor (PEDF) is a secreted glycoprotein belonging to the family of non inhibitory serpins. It is known, that in cases of complicated myopia, the content of PEDF in aqueous humor of the anterior chamber is significantly reduced. Here we examined a bulk of Tenon's capsule samples obtained from various groups of myopes, to examine PEDF processing in progressive myopia. We have analyzed the distribution of full length PEDF50 and its truncated form PEDF45 in the soluble and insoluble fractions extracted from Tenon's capsule of myopic and control (non-myopic) patients using SDS-polyacrylamide gel electrophoresis, as well as monitored the proteolytic degradation of PEDF ex vivo by enzyme-linked immunosorbent assay. These results were complemented by PEDF mRNA analysis in correspondent tissues by using qPCR and immunohistochemistry analysis of PEDF distribution in normal and myopic specimens. We found that in the Tenon's capsule of patients suffering from a high myopia the level of "soluble" 45 kDa PEDF reduced by 2-fold, while the content of "insoluble" 50 kDa form of PEDF was increased by 4-fold compared to controls. Excessive amount of PEDF50 in myopic specimens have been shown to correlate with the abrogated PEDF processing rather than with an increase of its expression. Moreover, immunohistochemical staining of the myopic Tenon's capsule tissue sections revealed the halo of deposited PEDF50 in the fibroblast extracellular space. These findings suggest that in myopia limited proteolysis of PEDF is altered or abrogated. Accumulation of full-length PEDF insoluble aggregates in the fibroblast intercellular space may affect cell survival and consequently causes the destructive changes in the extracellular matrix of the eye connective tissues. As a result, the abrogation of full-length PEDF normal processing can be an important mechanism leading to biomechanical destabilization of the scleral capsule and myopia progression.
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| 46. |
- Morozova-Roche, Ludmilla A, et al.
(author)
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Amyloid fibril formation and seeding by wild-type human lysozyme and its disease-related mutational variants
- 2000
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In: Journal of Structural Biology. - : Elsevier BV. - 1047-8477 .- 1095-8657. ; 130:2-3, s. 339-351
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Journal article (peer-reviewed)abstract
- Wild-type human lysozyme and its two stable amyloidogenic variants have been found to form partially folded states at low pH. These states are characterized by extensive disruption of tertiary interactions and partial loss of secondary structure. Incubation of the proteins at pH 2.0 and 37 degrees C (Ile56Thr and Asp67His variants) or 57 degrees C (wild-type) results in the formation of large numbers of fibrils over several days of incubation. Smaller numbers of fibrils could be observed under other conditions, including neutral pH. These fibrils were analyzed by electron microscopy, Congo red birefringence, thioflavine-T binding, and X-ray fiber diffraction, which unequivocally show their amyloid character. These data demonstrate that amyloidogenicity is an intrinsic property of human lysozyme and does not require the presence of specific mutations in its primary structure. The amyloid fibril formation is greatly facilitated, however, by the introduction of "seeds" of preformed fibrils to the solutions of the variant proteins, suggesting that seeding effects could be important in the development of systemic amyloidosis. Fibril formation by wild-type human lysozyme is greatly accelerated by fibrils of the variant proteins and vice versa, showing that seeding is not specific to a given protein. The fact that wild-type lysozyme has not been found in ex vivo deposits from patients suffering from this disease is likely to be related to the much lower population of incompletely folded states for the wild-type protein compared to its amyloidogenic variants under physiological conditions. These results support the concept that the ability to form amyloid is a generic property of proteins, but one that is mitigated against in a normally functioning organism.
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| 47. |
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| 48. |
- Morozova-Roche, Ludmilla A, et al.
(author)
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Structural characterisation and comparison of the native and A-states of equine lysozyme
- 1997
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In: Journal of Molecular Biology. - : Elsevier BV. - 0022-2836 .- 1089-8638. ; 268:5, s. 903-921
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Journal article (peer-reviewed)abstract
- Native state 1H NMR resonance assignments for 125 of the 129 residues of equine lysozyme have enabled measurement of the hydrogen exchange kinetics for over 60 backbone amide and three tryptophan indole hydrogen atoms in the native state. Native holo equine lysozyme hydrogen exchange protection factors are as large as 10(6), the most protected residues being located in elements of secondary structure. High exchange protection in the domain interface correlates with the binding of Ca2+ in this region. Equine lysozyme differs from most non-Ca2+ binding lysozymes in forming a highly populated partially folded state at low pH. The protein in this A-state at pH 2.0 has been found to bind 1-anilino-naphthalene-8-sulphonate with the enhancement of fluorescent intensity and blue shift in the spectral maximum characteristic of molten globules. NMR spectra indicate that the A-state is globally much less ordered than native equine lysozyme but does not contain significant regions of random coil structure. The amides most protected against hydrogen exchange in the A-state (protection factors up to 10(2) at 5 degrees C) correspond to residues of three of the four alpha-helices of the native state; the side-chains of these residues form a hydrophobic cluster that includes five aromatic residues. Circular dichroism and tryptophan fluorescence indicate that these residues are substantially more constrained than similar residues in "classical" molten globules. Taken together, the data suggest a model for the A-state of equine lysozyme in which a more ordered core is surrounded by a less ordered but still compact polypeptide chain.
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| 49. |
- Morozova-Roche, Ludmilla, et al.
(author)
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Calcium-binding lysozymes
- 2012
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Book (other academic/artistic)abstract
- In this book, the authors describe an important class of calcium binding lysozymes that are evolutionarily related to the lysozyme superfamily and the lactalbumins. The authors take the reader through a journey from the evolution, then the structure and properties of the calcium binding lysozymes. They discuss new unique protein folding pathways with local cooperative, close related folding modes that exhibit multiple folding pathways which are not properties of the lactalbumins or non calcium binding lysozymes. They comprise one of the most diverse group of examples in protein folding. In addition this protein class, especially equine lysozyme, shows peculiar amyloid assembly properties that are not common with other fibril forming proteins. It is one of the first shown to form ring shaped amyloids and other complexes in vitro. Lastly equine lysozyme forms complex with oleic acid, a unique form ELOA, which contributes to the family of the human and bovine lactalbumin analogs HAMLET and BAMLET.
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| 50. |
- Mossberg, Anki, et al.
(author)
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Structure and function of human α-lactalbumin made lethal to tumor cells (HAMLET)-type complexes.
- 2010
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In: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 277:22, s. 4614-4625
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Research review (peer-reviewed)abstract
- Human α-lactalbumin made lethal to tumor cells (HAMLET) and equine lysozyme with oleic acid (ELOA) are complexes consisting of protein and fatty acid that exhibit cytotoxic activities, drastically differing from the activity of their respective proteinaceous compounds. Since the discovery of HAMLET in the 1990s, a wealth of information has been accumulated, illuminating the structural, functional and therapeutic properties of protein complexes with oleic acid, which is summarized in this review. In vitro, both HAMLET and ELOA are produced by using ion-exchange columns preconditioned with oleic acid. However, the complex of human α-lactalbumin with oleic acid with the antitumor activity of HAMLET was found to be naturally present in the acidic fraction of human milk, where it was discovered by serendipity. Structural studies have shown that α-lactalbumin in HAMLET and lysozyme in ELOA are partially unfolded, 'molten-globule'-like, thereby rendering the complexes dynamic and in conformational exchange. HAMLET exists in the monomeric form, whereas ELOA mostly exists as oligomers and the fatty acid stoichiometry varies, with HAMLET holding an average of approximately five oleic acid molecules, whereas ELOA contains a considerably larger number (11- 48). Potent tumoricidal activity is found in both HAMLET and ELOA, and HAMLET has also shown strong potential as an antitumor drug in different in vivo animal models and clinical studies. The gain of new, beneficial function upon partial protein unfolding and fatty acid binding is a remarkable phenomenon, and may reflect a significant generic route of functional diversification of proteins via varying their conformational states and associated ligands.
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