Characterizing the aggregation, intrinsic fluorescence, and cellular effects of the functional amyloid neurokinin B

Abstract

Amyloid fibrils are implicated in several human diseases, including Alzheimer's and Parkinson’s Disease. In contrast many amyloid proteins have not been associated with toxicity and form fibrils to fulfill physiological roles; they have been collectively named functional amyloids. Amyloid fibrils exhibit an intrinsic fluorescence which has the potential to permit characterization of fibrils in cellulo and in vivo, however research on this property has been limited. The spectral phasor analysis technique can extrapolate more information than fluorescence imaging by identifying the spectral properties of fluorescence emission at a pixel-resolution which enables for characterization of individual microenvironments. Hyperspectral characterization of amyloid protein structure, aggregation, and interaction with cell organelles, specifically mitochondria, is likely to yield more information on the complex nature of amyloid proteins. In this thesis the functional amyloid peptide Neurokinin B (NKB) was investigated to characterize the factors that contribute to its assembly into amyloid fibrils. NKB is of particular interest because it is non-toxic in the amyloid form yet has sequence similarity to the hydrophobic core of Aβ1-42, the toxic amyloid associated with Alzheimer's Disease. This research expands on our understanding of the aggregation of functional amyloids. It identifies the hydrophobic aromatic interactions essential for the assembly of the important neuropeptide NKB and provides some key characteristics that may differentiate functional and toxic amyloids. This research further cements the universal property of AIF to all amyloid proteins and highlights its potential for in vitro characterization of aggregation, or disaggregation of amyloid fibrils.

Date of Award	2023
Original language	English
Awarding Institution	Western Sydney University
Supervisor	Christopher Jones (Supervisor), Mark Jones (Supervisor) & Stephen Mieruszynski (Supervisor)