# the contribution of APOE4 mediated bioenergetic deficits in the cerebrovascular dysfunction in Alzheimer's disease

> **NIH VA I01** · JAMES A. HALEY VA MEDICAL CENTER · 2024 · —

## Abstract

The apolipoprotein E (APOE) E4 allele is one of the main genetic risk factors for Alzheimer’s disease (AD) and
an important contributor to cerebrovascular (CV) dysfunction, which is a major component of AD pathogenesis.
Recent advances in AD research suggest that E4 carriers have an age-dependent vulnerability in supplying
glucose to the brain, which corresponds with lower glucose metabolism and precedes brain amyloid and tau
pathologies. The CV system regulates nutrient transport to the brain to support neuronal bioenergetics, but
aging individuals with the E4 allele experience deficits in this process. This eventually forces neurons to
perform fatty acid (FA) metabolism, which is harmful if performed in neurons given that it can contribute to
oxidative stress. The process of FA metabolism requires L-carnitine for transporting FA as acylcarnitines
(CAR) into mitochondria (L-carnitine bioenergetics). The importance of this system in AD is highlighted by our
recent study showing that L-carnitine bioenergetic deficits are present among E4 carriers and correlate with CV
pathologies seen with AD. Our animal studies show that pathways that link glucose sensing with L-carnitine-
bioenergetics are dysregulated in the cerebrovasculature and the brain parenchyma of humanized APOE4
mouse models. This corresponds with a loss of aquaporin-4 (AQP4) that facilitates glymphatic clearance of
Abeta from the brain. Therefore, we hypothesize that E4 disrupts L-carnitine bioenergetics within the brain
endothelial cells (BEC) and the mural cells, thereby reducing glucose availability in neurons and astrocytes.
This would also hamper the ability of astrocytes to perform glycolysis and L-carnitine bioenergetics, which
consequently increases the reliance on L-carnitine bioenergetics within neurons and contributes to oxidative
stress, inflammation and poor Abeta clearance from the brain. Hence, abnormal L-carnitine bioenergetics
caused by E4 in the neurovascular unit cells (BEC, mural cells, and astroglia) increase the brain’s vulnerability
to developing AD. To test this hypothesis, we will first determine whether BEC or mural cells experience
altered L-carnitine bioenergetics and determine the differential impact of APOE genotypes throughout aging in
mouse and human BEC and mural cells. We will then determine if increasing L-carnitine bioenergetics helps
restore nutrient balance in the neurons and astrocytes by utilizing selective knockout (KO) of acetyl-CoA
carboxylase (ACC1) in the BEC of APOE and AD mouse models. We will also evaluate if selective KO of
ACC1 in BEC of APOE and AD mouse models improves astroglial and neuronal bioenergetics and glymphatic
function to facilitate Abeta clearance from the brain parenchyma. The proposed studies will provide novel
insights into identifying molecular mechanisms within the L-carnitine bioenergetics pathways in order to
develop therapeutic options that specifically target the E4 carriers who experience a significantly higher
c...

## Key facts

- **NIH application ID:** 10806372
- **Project number:** 1I01BX006079-01A2
- **Recipient organization:** JAMES A. HALEY VA MEDICAL CENTER
- **Principal Investigator:** Laila Abdullah
- **Activity code:** I01 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2024
- **Award amount:** —
- **Award type:** 1
- **Project period:** 2024-04-01 → 2028-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10806372

## Citation

> US National Institutes of Health, RePORTER application 10806372, the contribution of APOE4 mediated bioenergetic deficits in the cerebrovascular dysfunction in Alzheimer's disease (1I01BX006079-01A2). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10806372. Licensed CC0.

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