The APOE–Microglia Axis in Alzheimer’s Disease: Functional Divergence and Therapeutic Perspectives—A Narrative Review

Apolipoprotein E (APOE) alleles play distinct roles in the pathogenesis of Alzheimer’s disease (AD), with <i>APOE</i>ε4 being the strongest genetic risk factor for late-onset AD, while <i>APOE</i>ε2 appears protective. Despite extensive research, the precise mechanisms by whi...

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Main Authors: Aiwei Liu, Tingxu Wang, Liu Yang, Yu Zhou
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Brain Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3425/15/7/675
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author Aiwei Liu
Tingxu Wang
Liu Yang
Yu Zhou
author_facet Aiwei Liu
Tingxu Wang
Liu Yang
Yu Zhou
author_sort Aiwei Liu
collection DOAJ
description Apolipoprotein E (APOE) alleles play distinct roles in the pathogenesis of Alzheimer’s disease (AD), with <i>APOE</i>ε4 being the strongest genetic risk factor for late-onset AD, while <i>APOE</i>ε2 appears protective. Despite extensive research, the precise mechanisms by which <i>APOE</i> alleles contribute to AD pathology remain incompletely understood. Recent advances in multi-omics technologies and single-cell analyses have revealed that <i>APOE</i> alleles shape microglial phenotypes, thereby affecting amyloid clearance, inflammatory responses, tau pathology, and lipid metabolism. In this review, we provide a detailed overview of how <i>APOE</i> alleles differentially regulate microglial activation, inflammatory signaling, phagocytic activity, and lipid metabolism in the context of AD, with a particular focus on the <i>APOE</i>ε4-mediated disruption of microglial homeostasis via pathways such as TREM2 signaling, NF-κB/NLRP3 activation, ACSL1 upregulation, and HIF-1α induction. These insights not only advance our understanding of <i>APOE</i> allele-specific contributions to AD pathology, but also highlight novel therapeutic strategies targeting the APOE–microglia axis.
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spelling doaj-art-e370e9fa5a8946d89d3cc3a0ade56c872025-08-20T03:58:30ZengMDPI AGBrain Sciences2076-34252025-06-0115767510.3390/brainsci15070675The APOE–Microglia Axis in Alzheimer’s Disease: Functional Divergence and Therapeutic Perspectives—A Narrative ReviewAiwei Liu0Tingxu Wang1Liu Yang2Yu Zhou3School of Basic Medical Sciences, Qingdao University, Qingdao 266071, ChinaSchool of Basic Medical Sciences, Qingdao University, Qingdao 266071, ChinaDepartment of Physiology, Binzhou Medical University, Yantai 264003, ChinaSchool of Life Sciences and Health, University of Health and Rehabilitation Sciences, Qingdao 266000, ChinaApolipoprotein E (APOE) alleles play distinct roles in the pathogenesis of Alzheimer’s disease (AD), with <i>APOE</i>ε4 being the strongest genetic risk factor for late-onset AD, while <i>APOE</i>ε2 appears protective. Despite extensive research, the precise mechanisms by which <i>APOE</i> alleles contribute to AD pathology remain incompletely understood. Recent advances in multi-omics technologies and single-cell analyses have revealed that <i>APOE</i> alleles shape microglial phenotypes, thereby affecting amyloid clearance, inflammatory responses, tau pathology, and lipid metabolism. In this review, we provide a detailed overview of how <i>APOE</i> alleles differentially regulate microglial activation, inflammatory signaling, phagocytic activity, and lipid metabolism in the context of AD, with a particular focus on the <i>APOE</i>ε4-mediated disruption of microglial homeostasis via pathways such as TREM2 signaling, NF-κB/NLRP3 activation, ACSL1 upregulation, and HIF-1α induction. These insights not only advance our understanding of <i>APOE</i> allele-specific contributions to AD pathology, but also highlight novel therapeutic strategies targeting the APOE–microglia axis.https://www.mdpi.com/2076-3425/15/7/675Alzheimer’s diseaseapolipoprotein Emicrogliainflammationphagocytosislipid metabolism
spellingShingle Aiwei Liu
Tingxu Wang
Liu Yang
Yu Zhou
The APOE–Microglia Axis in Alzheimer’s Disease: Functional Divergence and Therapeutic Perspectives—A Narrative Review
Brain Sciences
Alzheimer’s disease
apolipoprotein E
microglia
inflammation
phagocytosis
lipid metabolism
title The APOE–Microglia Axis in Alzheimer’s Disease: Functional Divergence and Therapeutic Perspectives—A Narrative Review
title_full The APOE–Microglia Axis in Alzheimer’s Disease: Functional Divergence and Therapeutic Perspectives—A Narrative Review
title_fullStr The APOE–Microglia Axis in Alzheimer’s Disease: Functional Divergence and Therapeutic Perspectives—A Narrative Review
title_full_unstemmed The APOE–Microglia Axis in Alzheimer’s Disease: Functional Divergence and Therapeutic Perspectives—A Narrative Review
title_short The APOE–Microglia Axis in Alzheimer’s Disease: Functional Divergence and Therapeutic Perspectives—A Narrative Review
title_sort apoe microglia axis in alzheimer s disease functional divergence and therapeutic perspectives a narrative review
topic Alzheimer’s disease
apolipoprotein E
microglia
inflammation
phagocytosis
lipid metabolism
url https://www.mdpi.com/2076-3425/15/7/675
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