Date of Graduation

7-2020

Document Type

Thesis

Degree Name

Master of Science in Cell & Molecular Biology (MS)

Degree Level

Graduate

Department

Cell & Molecular Biology

Advisor/Mentor

Thallapuranam, Suresh

Committee Member

Hettiarachchy, Navam S.

Second Committee Member

Adams, Paul D.

Third Committee Member

Moradi, Mahmoud

Keywords

Alzheimer's disease; Amyloid-fibrils; FGF-1; Heparin-binding pocket; Sodium dodecyl sulfate (SDS); Sucrose octa sulfate (SOS)

Abstract

Human acidic fibroblast growth factor (aFGF/hFGF-1) is one of the promising molecules to be investigated to generate an in-depth understanding of the pathological mechanism of Alzheimer's disease (AD) neurodegenerative disorder characterized by the presence of amyloid fibrils. Some in vivo and human brain tissue studies proved the correlation of high-level expression of FGF-1-induced neuroinflammation and the occurrence of AD. The presence of amyloid fibrils as a hallmark of AD can be related to the generic property of the proteins to form amyloid fibrils; High level of FGF-1, in this case, may contribute to the formation of amyloid fibrils. As a heparin-binding protein, hFGF-1 requires heparin to bind in the heparin-binding pocket to provide protection from proteolysis and heat inactivation and potentiate the mitogenic activity of FGF-1. Due to the importance of heparin-binding pocket to the native structural stability of the FGF-1, we hypothesized that destabilization of heparin-binding pocket might facilitate amyloid fibrils formation in FGF-1.

We carried out in vitro studies by using sodium dodecyl sulfate (SDS) as an amyloid fibril inducer and sucrose octasulfate (SOS) to mimic the activity of heparin to prove our hypothesis. Our study can be a preliminary step to understand the significant role of heparin-binding pocket in amyloid fibrils formation and explore its potential as a druggable site in search of the cure of AD. Fluorescence spectroscopy, limited trypsin digestion, transmission electron microscopy, and mass spectrometry were performed to achieve the objective of this research project. The results of this study suggest that 0.2mM is the optimum concentration of SDS to induce amyloid-like fibrils formation in hFGF-1 (wild-type FGF-1). The presence of SOS is found to protect hFGF-1 from fibrillation induced by SDS, reduce, and disaggregate fibrils formation in hFGF-1. Stabilization of the heparin-binding pocket renders the ability of hFGF-1 to protect and reduce the chance of amyloid fibrils formation.

Keywords: Alzheimer's disease, amyloid-fibrils, FGF-1, sodium dodecyl sulfate (SDS), sucrose octa sulfate (SOS), heparin-binding pocket.

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