title: Citrate-stabilized gold nanoparticles hinder fibrillogenesis of a pathological variant of β2-microglobulin.
abstract: Nanoparticles have repeatedly been shown to enhance fibril formation when assayed with amyloidogenic proteins. Recently, however, evidence casting some doubt about the generality of this conclusion started to emerge. Therefore, to investigate further the influence of nanoparticles on the fibrillation process, we used a naturally occurring variant of the paradigmatic amyloidogenic protein β2-microglobulin (β2m), namely D76N β2m where asparagine replaces aspartate at position 76. This variant is responsible for aggressive systemic amyloidosis. After characterizing the interaction of the variant with citrate-stabilized gold nanoparticles (Cit-AuNPs) by NMR and modeling, we analyzed the fibril formation by three different methods: thioflavin T fluorescence, native agarose gel electrophoresis and transmission electron microscopy. The NMR evidence indicated a fast-exchange interaction involving preferentially specific regions of the protein that proved, by subsequent modeling, to be consistent with a dimeric adduct interacting with Cit-AuNPs. The fibril detection assays showed that AuNPs are able to hamper D76N β2m fibrillogenesis through an effective interaction that competes with protofibril formation or recruitment. These findings open promising perspectives for the optimization of the nanoparticle surface to design tunable interactions with proteins.
authors.affiliation: DSMB, Università di Udine, P.le Kolbe 4, 33100 Udine, Italy. rino.esposito@uniud.it.
authors.forename: Cristina
authors.initials: C
authors.lastname: Cantarutti
authors.affiliation: Dipartimento Medicina Molecolare, Università di Pavia, Via Taramelli 3, 27100 Pavia, Italy and INBB, Viale Medaglie d'Oro 305, 00136 Roma, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Raimondi
authors.affiliation: CNR Istituto Nanoscienze, Via Campi 213/A, 41125 Modena, Italy. giorgia.brancolini@nano.cnr.it.
authors.forename: Giorgia
authors.initials: G
authors.lastname: Brancolini
authors.affiliation: DSMB, Università di Udine, P.le Kolbe 4, 33100 Udine, Italy. rino.esposito@uniud.it and INBB, Viale Medaglie d'Oro 305, 00136 Roma, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Corazza
authors.affiliation: Dipartimento Medicina Molecolare, Università di Pavia, Via Taramelli 3, 27100 Pavia, Italy and INBB, Viale Medaglie d'Oro 305, 00136 Roma, Italy.
authors.forename: Sofia
authors.initials: S
authors.lastname: Giorgetti
authors.affiliation: Science and Math Division, New York University at Abu Dhabi, Abu Dhabi, United Arab Emirates.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Ballico
authors.affiliation: Science and Math Division, New York University at Abu Dhabi, Abu Dhabi, United Arab Emirates.
authors.forename: Stefano
authors.initials: S
authors.lastname: Zanini
authors.affiliation: Department of Chemical and Environmental Engineering, Masdar Institute of Science and Technology, PO Box 54224, Abu Dhabi, United Arab Emirates.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Palmisano
authors.affiliation: Dipartimento Scienze della Vita, Università di Trieste, Via Weiss 2, 34128 Trieste, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Bertoncin
authors.affiliation: Dipartimento Medicina Molecolare, Università di Pavia, Via Taramelli 3, 27100 Pavia, Italy and INBB, Viale Medaglie d'Oro 305, 00136 Roma, Italy.
authors.forename: Loredana
authors.initials: L
authors.lastname: Marchese
authors.affiliation: Dipartimento Medicina Molecolare, Università di Pavia, Via Taramelli 3, 27100 Pavia, Italy and INBB, Viale Medaglie d'Oro 305, 00136 Roma, Italy and Division of Medicine, University College of London, London NW3 2PF, UK.
authors.forename: P
authors.initials: P
authors.lastname: Patrizia Mangione
authors.affiliation: Dipartimento Medicina Molecolare, Università di Pavia, Via Taramelli 3, 27100 Pavia, Italy and INBB, Viale Medaglie d'Oro 305, 00136 Roma, Italy and Division of Medicine, University College of London, London NW3 2PF, UK.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Bellotti
authors.affiliation: CNR Istituto Nanoscienze, Via Campi 213/A, 41125 Modena, Italy. giorgia.brancolini@nano.cnr.it.
authors.forename: Stefano
authors.initials: S
authors.lastname: Corni
authors.affiliation: DSMB, Università di Udine, P.le Kolbe 4, 33100 Udine, Italy. rino.esposito@uniud.it and INBB, Viale Medaglie d'Oro 305, 00136 Roma, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Fogolari
authors.affiliation: DSMB, Università di Udine, P.le Kolbe 4, 33100 Udine, Italy. rino.esposito@uniud.it and INBB, Viale Medaglie d'Oro 305, 00136 Roma, Italy and Science and Math Division, New York University at Abu Dhabi, Abu Dhabi, United Arab Emirates.
authors.forename: Gennaro
authors.identifier: http://orcid.org/0000-0001-9353-5423
authors.initials: G
authors.lastname: Esposito
mesh_terms: D000682:Amyloid / Q000737:chemistry; D019343:Citric Acid; D005453:Fluorescence; D006046:Gold; D053768:Metal Nanoparticles; D062105:Molecular Docking Simulation; D011487:Protein Conformation; D001613:beta 2-Microglobulin / Q000737:chemistry*
chemical_list: D000682:Amyloid; D001613:beta 2-Microglobulin; D019343:Citric Acid; D006046:Gold