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Published on: May 22, 2018
Multifaceted Influences of Melanin-Like Particles on Amyloid-beta Aggregation
Haeun Song1, Yoonyoung Kim1, Inkyu Kim1
1Department of Applied Chemistry, Kyung Hee University, 1732 Deogyoung-daero, Yongin, Gyeonggi, 17104, Republic of Korea.
Abstract:
The properties of eumelanin-like particles (EMPs) and pheomelanin-like particles (PMPs) in regulating the process of amyloid formation of amyloid-beta 42 (Aβ42) were examined. EMPs and PMPs are effective both in interfering with amyloid aggregation of Aβ42 and in remodeling matured Αβ42 fibers. The results suggest that some (but not all) molecular species consisting of melanin-like particles (MPs) are responsible for their inhibiting property toward amyloid formation, and the influence is likely manifested by long-range interactions. Incubating preformed Aβ42 fibers with catechols or MPs leads to the formation of mesh-like, interconnected Aβ42 fibers encapsulated with melanin-like material. MPs are kinetically more effective than catechol monomers in this process, and a detailed investigation reveals that 4,5-dihydroxyindole, a major intermediate in the formation of melanin-like species, and its derivatives are mainly responsible for remodeling amyloid fibers.
Insights
Melanin-like particles (EMPs and PMPs) effectively inhibit amyloid-beta 42 (Aβ42) aggregation and remodel existing Aβ42 fibers. Specific melanin components, like 4,5-dihydroxyindole, drive this fiber remodeling process.
Area of Science:
- Biochemistry
- Materials Science
- Neuroscience
Background:
- Amyloid-beta 42 (Aβ42) aggregation is central to Alzheimer's disease pathogenesis.
- Melanin-like particles (MPs) are natural pigments with potential biological activities.
- Understanding interactions between MPs and amyloid proteins is crucial for therapeutic development.
Purpose of the Study:
- To investigate the role of eumelanin-like particles (EMPs) and pheomelanin-like particles (PMPs) in modulating Aβ42 amyloid formation.
- To identify the specific molecular species within MPs responsible for inhibiting and remodeling Aβ42 aggregates.
Main Methods:
- Incubation of Aβ42 monomers and preformed fibers with EMPs and PMPs.
- Characterization of Aβ42 aggregation and fiber morphology using various techniques.
- Analysis of the contribution of specific catechol derivatives to fiber remodeling.
Main Results:
- EMPs and PMPs significantly interfere with Aβ42 aggregation and remodel mature Aβ42 fibers.
- Melanin-like particles are more kinetically effective than catechol monomers in remodeling.
- 4,5-dihydroxyindole and its derivatives were identified as key agents in remodeling amyloid fibers.
Conclusions:
- Certain molecular species within melanin-like particles possess potent inhibitory effects on Aβ42 amyloidogenesis.
- Melanin-like particles, particularly 4,5-dihydroxyindole, can remodel existing amyloid structures, suggesting therapeutic potential.
- Long-range interactions are likely involved in the inhibitory mechanism of MPs on amyloid formation.
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