How epigallocatechin gallate binds and assembles oligomeric forms of human alpha-synuclein

Andersen, Camilla; Yoshimura, Yuichi; Nielsen, Janni; Otzen, Daniel E.; Mulder, Frans A. A.

doi:10.1016/j.jbc.2021.100788

Cited by 13 publications

(12 citation statements)

References 55 publications

(108 reference statements)

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“…Transmission electron microscopy (TEM) was performed as described previously 50 with minor modifications. In brief, a 5 µl sample was applied to a 400-mesh carbon-coated, glow-discharged Ni grids for 30 s. The grids were stained with 2% uranyl formate and dried.…”

Section: Methodsmentioning

confidence: 99%

Low dose DMSO treatment induces oligomerization and accelerates aggregation of α-synuclein

Reimer

Haikal

Gram

et al. 2022

Sci Rep

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Dimethyl sulfoxide (DMSO) is a highly utilized small molecule that serves many purposes in scientific research. DMSO offers unique polar, aprotic and amphiphilic features, which makes it an ideal solvent for a wide variety of both polar and nonpolar molecules. Furthermore, DMSO is often used as a cryoprotectant in cell-based research. However, recent reports suggest that DMSO, even at low concentration, might interfere with important cellular processes, and cause macromolecular changes to proteins where a shift from α-helical to β-sheet structure can be observed. To investigate how DMSO might influence current research, we assessed biochemical and cellular impacts of DMSO treatment on the structure of the aggregation-prone protein α-synuclein, which plays a central role in the etiology of Parkinson’s disease, and other brain-related disorders, collectively termed the synucleinopathies. Here, we found that addition of DMSO increased the particle-size of α-synuclein, and accelerated the formation of seeding-potent fibrils in a dose-dependent manner. These fibrils made in the presence of DMSO were indistinguishable from fibrils made in pure PBS, when assessed by proteolytic digestion, cytotoxic profile and their ability to seed cellular aggregation of α-synuclein. Moreover, as evident through binding to the MJFR-14-6-4-2 antibody, which preferentially recognizes aggregated forms of α-synuclein, and a bimolecular fluorescence complementation assay, cells exposed to DMSO experienced increased aggregation of α-synuclein. However, no observable α-synuclein abnormalities nor differences in neuronal survival were detected after oral DMSO-treatment in either C57BL/6- or α-synuclein transgenic F28 mice. In summary, we demonstrate that low concentrations of DMSO makes α-synuclein susceptible to undergo aggregation both in vitro and in cells. This may affect experimental outcomes when studying α-synuclein in the presence of DMSO, and should call for careful consideration when such experiments are planned.

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Section: Methodsmentioning

confidence: 99%

Low dose DMSO treatment induces oligomerization and accelerates aggregation of α-synuclein

Reimer

Haikal

Gram

et al. 2022

Sci Rep

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“…The structural homogeneity of both type A* and type B* oligomeric samples allowed their structural characterization by solution-state and solid-state NMR . The interaction of EGCG with monomeric and oligomeric αSyn has also been studied extensively by solution-state NMR . αSyn is disordered in type A* oligomers, and the disordered core included the N-terminal region (residues 1–36) among other sequence regions.…”

Section: Insights Obtained From αSyn Oligomersmentioning

confidence: 99%

Characterization of Pairs of Toxic and Nontoxic Misfolded Protein Oligomers Elucidates the Structural Determinants of Oligomer Toxicity in Protein Misfolding Diseases

et al. 2023

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Conspectus The aberrant misfolding and aggregation of peptides and proteins into amyloid aggregates occurs in over 50 largely incurable protein misfolding diseases. These pathologies include Alzheimer’s and Parkinson’s diseases, which are global medical emergencies owing to their prevalence in increasingly aging populations worldwide. Although the presence of mature amyloid aggregates is a hallmark of such neurodegenerative diseases, misfolded protein oligomers are increasingly recognized as of central importance in the pathogenesis of many of these maladies. These oligomers are small, diffusible species that can form as intermediates in the amyloid fibril formation process or be released by mature fibrils after they are formed. They have been closely associated with the induction of neuronal dysfunction and cell death. It has proven rather challenging to study these oligomeric species because of their short lifetimes, low concentrations, extensive structural heterogeneity, and challenges associated with producing stable, homogeneous, and reproducible populations. Despite these difficulties, investigators have developed protocols to produce kinetically, chemically, or structurally stabilized homogeneous populations of protein misfolded oligomers from several amyloidogenic peptides and proteins at experimentally ameneable concentrations. Furthermore, procedures have been established to produce morphologically similar but structurally distinct oligomers from the same protein sequence that are either toxic or nontoxic to cells. These tools offer unique opportunities to identify and investigate the structural determinants of oligomer toxicity by a close comparative inspection of their structures and the mechanisms of action through which they cause cell dysfunction. This Account reviews multidisciplinary results, including from our own groups, obtained by combining chemistry, physics, biochemistry, cell biology, and animal models for pairs of toxic and nontoxic oligomers. We describe oligomers comprised of the amyloid-β peptide, which underlie Alzheimer’s disease, and α-synuclein, which are associated with Parkinson’s disease and other related neurodegenerative pathologies, collectively known as synucleinopathies. Furthermore, we also discuss oligomers formed by the 91-residue N-terminal domain of [NiFe]-hydrogenase maturation factor from E. coli, which we use as a model non-disease-related protein, and by an amyloid stretch of Sup35 prion protein from yeast. These oligomeric pairs have become highly useful experimental tools for studying the molecular determinants of toxicity characteristic of protein misfolding diseases. Key properties have been identified that differentiate toxic from nontoxic oligomers in their ability to induce cellular dysfunction. These characteristics include solvent-exposed hydrophobic regions, interactions with membranes, insertion into lipid bilayers, and disruption of plasma membrane integrity. By using these properties, it has been possible to rationalize in model systems the responses...

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“…Thus, it is critical to identify compounds that modulate the deleterious interactions of IDP oligomers with membranes. In this regard, several classes of compounds have been identified to date, including small molecules ( 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ), peptides/peptidomimetics ( 18 , 19 ), molecular chaperones ( 20 , 21 , 22 , 23 , 24 , 25 ), and antibodies ( 22 , 26 ). One notable ligand that has garnered significant attention in recent years is (-)-epigallocatechin-3-gallate (EGCG).…”

mentioning

confidence: 99%

Structural determinants of the interactions of catechins with Aβ oligomers and lipid membranes

Ahmed

Huang

Lifshitz

et al. 2022

Journal of Biological Chemistry

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The aberrant self-assembly of intrinsically disordered proteins (IDPs) into soluble oligomers and their interactions with biological membranes underlie the pathogenesis of numerous neurodegenerative diseases, including Alzheimer’s disease. Catechins have emerged as useful tools to reduce the toxicity of IDP oligomers by modulating their interactions with membranes. However, the structural determinants of catechin binding to IDP oligomers and membranes remain largely elusive. Here, we assemble a catechin library by combining several naturally occurring chemical modifications and, using a coupled NMR-statistical approach, we map at atomic resolution the interactions of such library with the Alzheimer’s-associated amyloid-beta (Aβ) oligomers and model membranes. Our results reveal multiple catechin affinity drivers and show that the combination of affinity-reducing covalent changes may lead to unexpected net gains in affinity. Interestingly, we find that the positive cooperativity is more prevalent for Aβ oligomers than membrane binding, and that the determinants underlying catechin recognition by membranes are markedly different from those dissected for Aβ oligomers. Notably, we find that the unanticipated positive cooperativity arises from the critical regulatory role of the gallate catechin moiety, which recruits previously disengaged substituents into the binding interface and leads to an overall greater compaction of the receptor-bound conformation. Overall, the previously elusive structural attributes mapped here provide an unprecedented foundation to establish structure-activity relationships of catechins.

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How epigallocatechin gallate binds and assembles oligomeric forms of human alpha-synuclein

Cited by 13 publications

References 55 publications

Low dose DMSO treatment induces oligomerization and accelerates aggregation of α-synuclein

Low dose DMSO treatment induces oligomerization and accelerates aggregation of α-synuclein

Characterization of Pairs of Toxic and Nontoxic Misfolded Protein Oligomers Elucidates the Structural Determinants of Oligomer Toxicity in Protein Misfolding Diseases

Structural determinants of the interactions of catechins with Aβ oligomers and lipid membranes

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