Structure-function relationship of human apolipoproteins:ApoE4 and Alzheimer's disease

Doctoral Dissertation uoadl:1309435 469 Read counter

Unit:
Τομέας ΙΙ [Οργανική Χημεία – Οργανική Χημική Τεχνολογία – Χημεία Τροφίμων]
Library of the School of Science
Deposit date:
2016-03-16
Year:
2016
Author:
Αργύρη Λέττα
Dissertation committee:
Μαίρη Μαυρή Βαβαγιάννη Αναπλ. Καθηγήτρια ΕΚΠΑ (Επιβλέπουσα), Ντία Γαλανοπούλου Καθηγήτρια ΕΚΠΑ, Αγγελική Χρόνη Ερευνήτρια Α΄Ινστιτούτο Βιοεπιστημών και Εφαρμογών, Ε.Κ.Ε.Φ.Ε «Δημόκριτος»
Original Title:
Σχέση δομής και λειτουργία των ανθρώπινων απολοποπρωτεϊνών: ΑποΕ4 και νόσος Alzheimer
Languages:
Greek
Translated title:
Structure-function relationship of human apolipoproteins:ApoE4 and Alzheimer's disease
Summary:
Apolipoprotein E4 (apoE4) isoform has consistently emerged as a susceptibility
factor for sporadic Alzheimer’s disease (AD), although the exact mechanism is
not clear. The elucidation of the pathogenic role of apoE4 in AD requires the
production of large amounts of pure apoE4. For this purpose, we developed a
simple procedure for the expression and purification of recombinant apoE4. Our
approach is based on the expression of a thioredoxin-apoE4 fusion construct in
bacterial cells and subsequent removal of the fused thioredoxin using the
highly specific 3C protease. Our approach results in rapid, high-yield
production of structurally and functionally competent apoE4.
A rare apoE4 variant, apoE4[L28P], burdens carriers with added risk for
sporadic AD and may be a useful tool for gaining insight on the role of apoE4
in disease pathogenesis. Towards this end, we evaluated the effect of the L28P
mutation on the structural and functional properties of apoE4. ApoE4[L28P],
produced with our newly developed approach, was found to have reduced helical
content, to be thermodynamically destabilized and to expose a larger portion
of hydrophobic surface to the solvent. Furthermore, this variant is more prone
to proteolysis. When interacting with lipids, apoE4 [L28P] formed populations
of lipoprotein particles with structural defects. The structural perturbations
brought about by the mutation were accompanied by aberrant functions associated
with the pathogenesis of AD. Specifically, apoE4[L28P] promoted the cellular
uptake of extracellular Aβ42 by human neuroblastoma SK-N-SH cells and primary
mouse neuronal cells and led to increased formation of reactive oxygen species
(ROS) that persisted for at least 24hrs. Finally, lipoprotein particles
containing apoE4[L28P] promoted ROS formation and reduced SK-N-SH cell
viability. Overall, our data suggest that the L28P mutation significantly
affects the structure of apoE4 both in solution and in lipoprotein particles
and that these effects may underlie apoE4 functional disturbances in neurons
that could be associated with AD pathogenesis.
Keywords:
Apolipoprotein E4, Alzheimer’s disease, recombinant apoE production, apoE structure, apoE function
Index:
Yes
Number of index pages:
1-9
Contains images:
Yes
Number of references:
400
Number of pages:
218
File:
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