title: What Can the Kinetics of Amyloid Fibril Formation Tell about Off-pathway Aggregation?
abstract: Some of the most prevalent neurodegenerative diseases are characterized by the accumulation of amyloid fibrils in organs and tissues. Although the pathogenic role of these fibrils has not been completely established, increasing evidence suggests off-pathway aggregation as a source of toxic/detoxicating deposits that still remains to be targeted. The present work is a step toward the development of off-pathway modulators using the same amyloid-specific dyes as those conventionally employed to screen amyloid inhibitors. We identified a series of kinetic signatures revealing the quantitative importance of off-pathway aggregation relative to amyloid fibrillization; these include non-linear semilog plots of amyloid progress curves, highly variable end point signals, and half-life coordinates weakly influenced by concentration. Molecules that attenuate/intensify the magnitude of these signals are considered promising off-pathway inhibitors/promoters. An illustrative example shows that amyloid deposits of lysozyme are only the tip of an iceberg hiding a crowd of insoluble aggregates. Thoroughly validated using advanced microscopy techniques and complementary measurements of dynamic light scattering, CD, and soluble protein depletion, the new analytical tools are compatible with the high-throughput methods currently employed in drug discovery.
authors.affiliation: From the Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia, Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
authors.forename: Rosa
authors.initials: R
authors.lastname: Crespo
authors.affiliation: the Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, 15782 Spain, and.
authors.forename: Eva
authors.initials: E
authors.lastname: Villar-Alvarez
authors.affiliation: the Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, 15782 Spain, and.
authors.forename: Pablo
authors.initials: P
authors.lastname: Taboada
authors.affiliation: From the Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia, Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
authors.forename: Fernando A
authors.initials: FA
authors.lastname: Rocha
authors.affiliation: the Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Damas
authors.affiliation: From the Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia, Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal,; the Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal. Electronic address: pmmartins@icbas.up.pt.
authors.forename: Pedro M
authors.initials: PM
authors.lastname: Martins
mesh_terms: D000682:Amyloid / Q000737:chemistry / Q000378:metabolism*; D002942:Circular Dichroism; D006207:Half-Life; D007700:Kinetics; D066329:Protein Aggregates; D017434:Protein Structure, Tertiary
chemical_list: D000682:Amyloid; D066329:Protein Aggregates
keywords: amyloid; biophysics; drug screening; kinetics; mathematical modeling; protein aggregation