Inhibition of ACAT as a Therapeutic Target for Alzheimer's Disease Is Independent of ApoE4 Lipidation

© 2023. The Author(s)..

APOE4, encoding apolipoprotein E4 (apoE4), is the greatest genetic risk factor for Alzheimer's disease (AD), compared to the common APOE3. While the mechanism(s) underlying APOE4-induced AD risk remains unclear, increasing the lipidation of apoE4 is an important therapeutic target as apoE4-lipoproteins are poorly lipidated compared to apoE3-lipoproteins. ACAT (acyl-CoA: cholesterol-acyltransferase) catalyzes the formation of intracellular cholesteryl-ester droplets, reducing the intracellular free cholesterol (FC) pool. Thus, inhibiting ACAT increases the FC pool and facilitates lipid secretion to extracellular apoE-containing lipoproteins. Previous studies using commercial ACAT inhibitors, including avasimibe (AVAS), as well as ACAT-knock out (KO) mice, exhibit reduced AD-like pathology and amyloid precursor protein (APP) processing in familial AD (FAD)-transgenic (Tg) mice. However, the effects of AVAS with human apoE4 remain unknown. In vitro, AVAS induced apoE efflux at concentrations of AVAS measured in the brains of treated mice. AVAS treatment of male E4FAD-Tg mice (5xFAD+/-APOE4+/+) at 6-8 months had no effect on plasma cholesterol levels or distribution, the original mechanism for AVAS treatment of CVD. In the CNS, AVAS reduced intracellular lipid droplets, indirectly demonstrating target engagement. Surrogate efficacy was demonstrated by an increase in Morris water maze measures of memory and postsynaptic protein levels. Amyloid-beta peptide (Aβ) solubility/deposition and neuroinflammation were reduced, critical components of APOE4-modulated pathology. However, there was no increase in apoE4 levels or apoE4 lipidation, while amyloidogenic and non-amyloidogenic processing of APP were significantly reduced. This suggests that the AVAS-induced reduction in Aβ via reduced APP processing was sufficient to reduce AD pathology, as apoE4-lipoproteins remained poorly lipidated.

Medienart:

E-Artikel

Erscheinungsjahr:

2023

Erschienen:

2023

Enthalten in:

Zur Gesamtaufnahme - volume:20

Enthalten in:

Neurotherapeutics : the journal of the American Society for Experimental NeuroTherapeutics - 20(2023), 4 vom: 15. Juli, Seite 1120-1137

Sprache:

Englisch

Beteiligte Personen:

Valencia-Olvera, Ana C [VerfasserIn]
Balu, Deebika [VerfasserIn]
Faulk, Naomi [VerfasserIn]
Amiridis, Aspasia [VerfasserIn]
Wang, Yueting [VerfasserIn]
Pham, Christine [VerfasserIn]
Avila-Munoz, Eva [VerfasserIn]
York, Jason M [VerfasserIn]
Thatcher, Gregory R J [VerfasserIn]
LaDu, Mary Jo [VerfasserIn]

Links:

Volltext

Themen:

97C5T2UQ7J
ACAT-1
APOE4
APP processing
Alzheimer’s disease
Amyloid beta-Peptides
Apolipoprotein E3
Apolipoprotein E4
Apolipoproteins E
Cholesterol
Journal Article
Neuroinflammation
Oligomeric Aβ
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

Anmerkungen:

Date Completed 28.08.2023

Date Revised 16.02.2024

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1007/s13311-023-01375-3

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM356601706