Biomimetic Microdroplet Membrane Interface: Detection of the Lateral Localization of Amyloid Beta Peptides

Abstract

Lateral membrane organization into domains, such as lipid rafts, plays an important role in the selective association of biological and nonbiological materials on heterogeneous membrane surfaces. The localization of such materials has profound influence on cellular responses. We constructed a biomimetic water-in-oil microdroplet membrane to study the lateral localization of these materials at heterogeneous biological interfaces. As a case study, we studied selective association of amyloid β peptide on the constructed membrane surface. Amyloid β peptide has attracted much attention as one of these membraneassociating proteins because of its "role" in Alzheimer's disease pathology. Ternary lipid membranes covering microdroplets successfully produced lipid ordered structures, which mimicked biological lipid rafts. We revealed that amyloid β peptide selectively localizes within nonraft fluid membrane regions. The successful lateral organization in microdroplet membrane systems may lead to new opportunities for the study of molecular associations within heterogeneous membranes.

Small Liposomes Accelerate the Fibrillation of Amyloid β (1–40)

“…Finally, although lipid rafts have been considered to play an important role in A␤ fibrillation (13, 16 -19), the underlying mechanism remains unclear (21,22). It is possible that the lipid raft carries the site of productive binding, as proposed here more than the other lipid membranes.…”

“…cholesterol, sphingomyelin, ganglioside, etc.) interact specifically with A␤ peptides, and this interaction has an important role in A␤ fibrillation (13, 16 -20); however, other studies challenged this proposal (21,22). Recently, a two-step mechanism of membrane disruption by A␤ peptides has been proposed in which (i) A␤ oligomers bind to the membrane to form ion-permeable pores, and (ii) the process of A␤ fibrillation causes membrane disruption mainly due to the interaction of A␤ fibrils with gangliosides (20,23).…”

Versatility of Reverse Micelles: From Biomimetic Models to Nano (Bio)Sensor Design

“…Their similarity with natural structures from the membranes of living cells unequivocally confers them with the status of a membrane-mimetic system. For example, Hamada et al constructed a biomimetic water-in-oil microdroplet membrane based on ternary lipids of dioleoyl L-α phosphatidylcholine/saturated dipalmitoyl L-α phosphatidylcholine/cholesterol, to study the lateral localization of the amyloid β peptide at this heterogeneous membrane interface in the presence and absence of a ganglioside lipid raft [155]. Amyloid β peptide was used for selective association on the constructed membrane surface, due to the important role of this peptide in Alzheimer's disease pathology, where it was considered that the interaction between this peptide and a lipid raft consisting of ganglioside leads to an acceleration of amyloid β peptide aggregation.…”

Amyloid – Membrane Interactions: Experimental Approaches and Techniques

“…Confocal microscopy was also used in that study for co-localization of IAPP aggregates and specific membrane lipids, in which the aggregates were dyed with Congo-red while the lipids were labeled with probe exhibiting different excitation/emission wavelengths. Hamada et al recently depicted a microscopy analysis of fluorescently-labeled A (1-40) segregated into fluid lipid domains formed within heterogeneous lipid layers in oil/water microdroplets [45].…”