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  • 1.
    Brännström, Kristoffer
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Lindhagen Persson, Malin
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Gharabyan, A
    Vestling, M
    Brännström, Thomas
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Design of oligomer-specific antibodiesManuscript (preprint) (Other academic)
  • 2.
    Brännström, Kristoffer
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Lindhagen-Persson, Malin
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Gharibyan, Anna L.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Iakovleva, Irina
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Vestling, Monika
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Sellin, Mikael E.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Brännström, Thomas
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Forsgren, Lars
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    A Generic Method for Design of Oligomer-Specific Antibodies2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 3, p. e90857-Article in journal (Refereed)
    Abstract [en]

    Antibodies that preferentially and specifically target pathological oligomeric protein and peptide assemblies, as opposed to their monomeric and amyloid counterparts, provide therapeutic and diagnostic opportunities for protein misfolding diseases. Unfortunately, the molecular properties associated with oligomer-specific antibodies are not well understood, and this limits targeted design and development. We present here a generic method that enables the design and optimisation of oligomer-specific antibodies. The method takes a two-step approach where discrimination between oligomers and fibrils is first accomplished through identification of cryptic epitopes exclusively buried within the structure of the fibrillar form. The second step discriminates between monomers and oligomers based on differences in avidity. We show here that a simple divalent mode of interaction, as within e. g. the IgG isotype, can increase the binding strength of the antibody up to 1500 times compared to its monovalent counterpart. We expose how the ability to bind oligomers is affected by the monovalent affinity and the turnover rate of the binding and, importantly, also how oligomer specificity is only valid within a specific concentration range. We provide an example of the method by creating and characterising a spectrum of different monoclonal antibodies against both the A beta peptide and alpha-synuclein that are associated with Alzheimer's and Parkinson's diseases, respectively. The approach is however generic, does not require identification of oligomer-specific architectures, and is, in essence, applicable to all polypeptides that form oligomeric and fibrillar assemblies.

  • 3.
    Brännström, Kristoffer
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Öhman, Anders
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Lindhagen-Persson, Malin
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Ca2+ enhances Aβ polymerization rate and fibrillar stability in a dynamic manner2013In: Biochemical Journal, ISSN 0264-6021, E-ISSN 1470-8728, Vol. 450, p. 189-197Article in journal (Refereed)
    Abstract [en]

    Identifying factors that affect the self-assembly of the amyloid-β peptide (Aβ) is of utmost importance in the quest to understand the molecular mechanisms causing Alzheimer's disease (AD). Ca2+ has previously been shown to accelerate both Aβ fibril nucleation and maturation, and a dysregulated Ca2+ homeostasis frequently correlates with development of AD. The mechanisms regarding Ca2+ binding as well as its effect on fibril kinetics are not fully understood. Using a polymerization assay we show that Ca2+ in a dynamic and reversible manner enhances both the elongation rate and fibrillar stability, where specifically the "dock and lock" phase mechanism is enhanced. Through NMR analysis we found that Ca2+ affects the fibrillar architecture. In addition, and unexpectedly, we found that Ca2+ does not bind the free Aβ monomer. This implies that Ca2+ binding requires an architecture adopted by assembled peptides, and consequently is mediated through intermolecular interactions between adjacent peptides. This gives a mechanistic explanation to the enhancing effect on fibril maturation and indicates structural similarities between prefibrillar structures and mature amyloid. Taken together we expose how Ca2+ levels affect the delicate equilibrium between the monomeric and assembled Aβ and how fluctuations in vivo may contribute to development and progression of the disease.

  • 4.
    Iakovleva, Irina
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Begum, Afshan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Pokrzywa, Malgorzata
    Walfridsson, Malin
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Sauer-Eriksson, A Elisabeth
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    The flavonoid luteolin, but not luteolin-7-o-glucoside, prevents a transthyretin mediated toxic response2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 5, article id e0128222Article in journal (Refereed)
    Abstract [en]

    Transthyretin (TTR) is a homotetrameric plasma protein with amyloidogenic properties that has been linked to the development of familial amyloidotic polyneuropathy (FAP), familial amyloidotic cardiomyopathy, and senile systemic amyloidosis. The in vivo role of TTR is associated with transport of thyroxine hormone T4 and retinol-binding protein. Loss of the tetrameric integrity of TTR is a rate-limiting step in the process of TTR amyloid formation, and ligands with the ability to bind within the thyroxin binding site (TBS) can stabilize the tetramer, a feature that is currently used as a therapeutic approach for FAP. Several different flavonoids have recently been identified that impair amyloid formation. The flavonoid luteolin shows therapeutic potential with low incidence of unwanted side effects. In this work, we show that luteolin effectively attenuates the cytotoxic response to TTR in cultured neuronal cells and rescues the phenotype of a Drosophila melanogaster model of FAP. The plant-derived luteolin analogue cynaroside has a glucoside group in position 7 of the flavone A-ring and as opposed to luteolin is unable to stabilize TTR tetramers and thus prevents a cytotoxic effect. We generated high-resolution crystal-structures of both TTR wild type and the amyloidogenic mutant V30M in complex with luteolin. The results show that the A-ring of luteolin, in contrast to what was previously suggested, is buried within the TBS, consequently explaining the lack of activity from cynaroside. The flavonoids represent an interesting group of drug candidates for TTR amyloidosis. The present investigation shows the potential of luteolin as a stabilizer of TTR in vivo. We also show an alternative orientation of luteolin within the TBS which could represent a general mode of binding of flavonoids to TTR and is of importance concerning the future design of tetramer stabilizing drugs.

  • 5.
    Lindhagen Persson, Malin
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Targeting cytotoxic species in amyloid diseases2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Amyloid diseases are a world-wide problem causing great human suffer and large economical costs. Although amyloid deposits, a common denominator in all amyloid disorders, are detrimental to the surrounding tissue, there is a poor correlation between total amyloid burden and clinical symptoms. Soluble oligomers are much more potent to exert a tissue damaging effect. 

    Alzheimer’s disease (AD) is strongly linked to self-assembly of the amyloid-β (Aβ) peptide. Antibodies selectively targeting cytotoxic Aβ-species are useful both for understanding oligomer formation and for their therapeutic abilities. We hypothesized that the effect of avidity would compensate for a low single site affinity and be enough to selectively target oligomers. To evaluate this hypothesis, we focused on the IgM isotype having ten antigen-binding sites. In accordance with the hypothesis, the IgM isotype effectively bound oligomeric Aβ also in presence of a vast excess of its monomeric counterpart, clearly illustrating the potentiating effect of avidity. As a continuation of this work, we have shown that the avidity effect from a bivalent binding is enough to induce oligomer specificity. This finding facilitates a direct application on the clinically more useful IgG isotype, where the binding properties now can be controlled in detail. The method is general and we have, using this technique, also designed oligomer specific antibodies targeting α-synuclein.

    Transthyretin (TTR) is an amyloidogenic protein involved in both hereditary and sporadic amyloidosis. The cytotoxicity of TTR is intriguing since studies have shown cytotoxic potential from oligomers, tetramers and even monomers. Elucidation of the molecular properties associated with TTR cytotoxicity is hence of interest. By preventing tetramer dissociation, TTR aggregation and TTR-induced cytotoxicity is abolished. Based on this rationale, a current therapeutic strategy is to stabilize the TTR tetramer with small molecules. The kinetic stability within the spectra of known TTR mutations spans more than three orders of magnitude. However, although the most stable mutants are inert, a poor correlation within the group of cytotoxic variants exists where the cytotoxic effect is not potentiated in proportion to their kinetic stability. Through analysis of a large spectra of TTR variants, our results indicate that TTR induced cytotoxicity requires an intermediate stability of the TTR molecule. The kinetic stability should be low enough to permit tetramer dissociation and the thermodynamic stability high enough to prevent instant aggregation and to allow formation of the cytotoxic fold. 

  • 6.
    Lindhagen Persson, Malin
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Diez, I
    Vestling, M
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Cytotoxic properties of transthyretin as a function of thermodynamic and kinetic stabilityManuscript (preprint) (Other academic)
  • 7.
    Lindhagen-Persson, Malin
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Brännström, Kristoffer
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Vestling, Monika
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Steinitz, Michael
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Amyloid-β oligomer specificity mediated by the IgM isotype: implications for a specific protective mechanism exerted by endogenous auto-antibodies2010In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 5, no 11, p. e13928-Article in journal (Refereed)
    Abstract [en]

    Background Alzheimers disease (AD) has been strongly linked to an anomalous self-assembly of the amyloid-β peptide (Aβ). The correlation between clinical symptoms of AD and Aβ depositions is, however, weak. Instead small and soluble Aβ oligomers are suggested to exert the major pathological effects. In strong support of this notion, immunological targeting of Aβ oligomers in AD mice-models shows that memory impairments can be restored without affecting the total burden of Aβ deposits. Consequently a specific immunological targeting of Aβ oligomers is of high therapeutic interest.

    Methodology/Principal Findings Previously the generation of conformational-dependent oligomer specific anti-Aβ antibodies has been described. However, to avoid the difficult task of identifying a molecular architecture only present on oligomers, we have focused on a more general approach based on the hypothesis that all oligomers expose multiple identical epitopes and therefore would have an increased binding to a multivalent receptor. Using the polyvalent IgM immunoglobulin we have developed a monoclonal anti-Aβ antibody (OMAB). OMAB only demonstrates a weak interaction with Aβ monomers and dimers having fast on and off-rate kinetics. However, as an effect of avidity, its interaction with Aβ-oligomers results in a strong complex with an exceptionally slow off-rate. Through this mechanism a selectivity towards Aβ oligomers is acquired and OMAB fully inhibits the cytotoxic effect exerted by Aβ(1-42) at highly substoichiometric ratios. Anti-Aβ auto-antibodies of IgM isotype are frequently present in the sera of humans. Through a screen of endogenous anti-Aβ IgM auto-antibodies from a group of healthy individuals we show that all displays a preference for oligomeric Aβ.

    Conclusions/Significance Taken together we provide a simple and general mechanism for targeting of oligomers without the requirement of conformational-dependent epitopes. In addition, our results suggest that IgM anti-Aβ auto-antibodies may exert a more specific protective mechanism in vivo than previously anticipated.

  • 8.
    Lindhagen-Persson, Malin
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Vestling, M
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Reixach, N
    Division of Rheumatology Research, W.M. Keck Autoimmune Disease Center, The Scripps Research Institute, La Jolla, CA, USA.
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Formation of cytotoxic transthyretin is not dependent on inter-molecular disulphide bridges commonly found within the amyloid form2008In: Amyloid: Journal of Protein Folding Disorders, ISSN 1350-6129, E-ISSN 1744-2818, Vol. 15, no 4, p. 240-245Article in journal (Refereed)
    Abstract [en]

    Familial amyloidotic polyneuropathy (FAP) is linked to destabilising point mutations in the human plasma protein transthyretin (TTR). Consistent with similar amyloid disorders, low molecular weight TTR oligomers have been shown to exert the major cytotoxic effect. The amyloid structure of TTR contains non-native inter-molecular disulphide linkages via the cysteine at position 10 (Cys10). Moreover, substitution of Cys10 in a mouse model for TTR-amyloidosis abolishes TTR deposits, indicating an important role of Cys10 in FAP pathogenesis. However, the role of disulphide bridges in TTR cytotoxicity has not been elucidated. By probing Cys10Ser TTR variants to the human neuroblastoma SH-SY5Y cell line, we have addressed this question, and our results clearly show that formation of an inter-molecular disulphide bridge is not a pre-requisite for TTR cytotoxicity. This finding suggests that prevention of inter-molecular TTR disulphide bridges as a therapeutic intervention will not impair the cytotoxic potential of TTR.

  • 9.
    Olofsson, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Lindhagen Persson, Malin
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Vestling, Monika
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Sauer-Eriksson, Elisabeth
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Öhman, Anders
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Quenched hydrogen/deuterium exchange NMR characterization of amyloid-β peptide aggregates formed in the presence of Cu2+ or Zn2+2009In: The FEBS Journal, ISSN 1742-464X, E-ISSN 1742-4658, Vol. 276, no 15, p. 4051-4060Article in journal (Refereed)
    Abstract [en]

    Alzheimer's disease, a neurodegenerative disorder causing synaptic impairment and neuronal cell death, is strongly correlated with aggregation of the amyloid-β peptide (Aβ). Divalent metal ions such as Cu2+ and Zn2+ are known to significantly affect the rate of aggregation and morphology of Aβ assemblies in vitro and are also found at elevated levels within cerebral plaques in vivo. The present investigation characterized the architecture of the aggregated forms of Aβ(1–40) and Aβ(1–42) in the presence or absence of either Cu2+ or Zn2+ using quenched hydrogen/deuterium exchange combined with solution NMR spectroscopy. The NMR analyses provide a quantitative and residue-specific structural characterization of metal-induced Aβ aggregates, showing that both the peptide sequence and the type of metal ion exert an impact on the final architecture. Common features among the metal-complexed peptide aggregates are two solvent-protected regions with an intervening minimum centered at Asn27, and a solvent-accessible N-terminal region, Asp1–Lys16. Our results suggest that Aβ in complex with either Cu2+ or Zn2+ can attain an aggregation-prone β-strand–turn–β-strand motif, similar to the motif found in fibrils, but where the metal binding to the N-terminal region guides the peptide into an assembly distinctly different from the fibril form.

  • 10. Treusch, Sebastian
    et al.
    Hamamichi, Shusei
    Goodman, Jessica L
    Matlack, Kent ES
    Chung, Chee Yeun
    Baru, Valeriya
    Shulman, Joshua M
    Parrado, Antonio
    Bevis, Brooke J
    Valastyan, Julie S
    Han, Haesun
    Lindhagen-Persson, Malin
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Reiman, Eric M
    Evans, Denis A
    Bennett, David A
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Dejager, Philip L
    Tanzi, Rudolph E
    Caldwell, Kim A
    Caldwell, Guy A
    Lindquist, Susan
    Functional links between Aβ toxicity, endocytic trafficking, and Alzheimer's disease risk factors in yeast2011In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 334, no 6060, p. 1241-1245Article in journal (Refereed)
    Abstract [en]

    Aβ (beta amyloid peptide) is an important contributor to Alzheimer's disease (AD). We modeled Aβ toxicity in yeast by directing the peptide to the secretory pathway. A genome-wide screen for toxicity modifiers identified the yeast homolog of phosphatidylinositol binding clathrin assembly protein (PICALM) and other endocytic factors connected to AD whose relationship to Aβ was previously unknown. The factors identified in yeast modified Aβ toxicity in glutamatergic neurons of Caenorhabditis elegans and in primary rat cortical neurons. In yeast, Aβ impaired the endocytic trafficking of a plasma membrane receptor, which was ameliorated by endocytic pathway factors identified in the yeast screen. Thus, links between Aβ, endocytosis, and human AD risk factors can be ascertained using yeast as a model system.

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