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Jackson RJ, Hyman BT, Serrano-Pozo A. Multifaceted roles of APOE in Alzheimer disease. Nat Rev Neurol 2024:10.1038/s41582-024-00988-2. [PMID: 38906999 DOI: 10.1038/s41582-024-00988-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2024] [Indexed: 06/23/2024]
Abstract
For the past three decades, apolipoprotein E (APOE) has been known as the single greatest genetic modulator of sporadic Alzheimer disease (AD) risk, influencing both the average age of onset and the lifetime risk of developing AD. The APOEε4 allele significantly increases AD risk, whereas the ε2 allele is protective relative to the most common ε3 allele. However, large differences in effect size exist across ethnoracial groups that are likely to depend on both global genetic ancestry and local genetic ancestry, as well as gene-environment interactions. Although early studies linked APOE to amyloid-β - one of the two culprit aggregation-prone proteins that define AD - in the past decade, mounting work has associated APOE with other neurodegenerative proteinopathies and broader ageing-related brain changes, such as neuroinflammation, energy metabolism failure, loss of myelin integrity and increased blood-brain barrier permeability, with potential implications for longevity and resilience to pathological protein aggregates. Novel mouse models and other technological advances have also enabled a number of therapeutic approaches aimed at either attenuating the APOEε4-linked increased AD risk or enhancing the APOEε2-linked AD protection. This Review summarizes this progress and highlights areas for future research towards the development of APOE-directed therapeutics.
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Affiliation(s)
- Rosemary J Jackson
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Bradley T Hyman
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.
- Harvard Medical School, Boston, MA, USA.
- Massachusetts Alzheimer's Disease Research Center, Charlestown, MA, USA.
| | - Alberto Serrano-Pozo
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.
- Harvard Medical School, Boston, MA, USA.
- Massachusetts Alzheimer's Disease Research Center, Charlestown, MA, USA.
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2
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Liu LC, Liang JY, Liu YH, Liu B, Dong XH, Cai WH, Zhang N. The Intersection of cerebral cholesterol metabolism and Alzheimer's disease: Mechanisms and therapeutic prospects. Heliyon 2024; 10:e30523. [PMID: 38726205 PMCID: PMC11079309 DOI: 10.1016/j.heliyon.2024.e30523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 04/26/2024] [Accepted: 04/29/2024] [Indexed: 05/12/2024] Open
Abstract
Alzheimer's disease (AD) is a common neurodegenerative disease in the elderly, the exact pathogenesis of which remains incompletely understood, and effective preventive and therapeutic drugs are currently lacking. Cholesterol plays a vital role in cell membrane formation and neurotransmitter synthesis, and its abnormal metabolism is associated with the onset of AD. With the continuous advancement of imaging techniques and molecular biology methods, researchers can more accurately explore the relationship between cholesterol metabolism and AD. Elevated cholesterol levels may lead to vascular dysfunction, thereby affecting neuronal function. Additionally, abnormal cholesterol metabolism may affect the metabolism of β-amyloid protein, thereby promoting the onset of AD. Brain cholesterol levels are regulated by multiple factors. This review aims to deepen the understanding of the subtle relationship between cholesterol homeostasis and AD, and to introduce the latest advances in cholesterol-regulating AD treatment strategies, thereby inspiring readers to contemplate deeply on this complex relationship. Although there are still many unresolved important issues regarding the risk of brain cholesterol and AD, and some studies may have opposite conclusions, further research is needed to enrich our understanding. However, these findings are expected to deepen our understanding of the pathogenesis of AD and provide important insights for the future development of AD treatment strategies targeting brain cholesterol homeostasis.
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Affiliation(s)
- Li-cheng Liu
- Pharmaceutical Branch, Harbin Pharmaceutical Group Co., Harbin, Heilongjiang Province, China
| | - Jun-yi Liang
- Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang Province, China
| | - Yan-hong Liu
- Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang Province, China
| | - Bin Liu
- Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang Province, China
| | - Xiao-hong Dong
- Jiamusi College, Heilongjiang University of Traditional Chinese Medicine, Jiamusi, Heilongjiang Province, China
| | - Wen-hui Cai
- Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang Province, China
| | - Ning Zhang
- Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang Province, China
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3
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Henningfield CM, Soni N, Lee RW, Sharma R, Cleland JL, Green KN. Selective targeting and modulation of plaque associated microglia via systemic hydroxyl dendrimer administration in an Alzheimer's disease mouse model. Alzheimers Res Ther 2024; 16:101. [PMID: 38711159 PMCID: PMC11071231 DOI: 10.1186/s13195-024-01470-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 04/29/2024] [Indexed: 05/08/2024]
Abstract
BACKGROUND In Alzheimer's disease (AD), microglia surround extracellular plaques and mount a sustained inflammatory response, contributing to the pathogenesis of the disease. Identifying approaches to specifically target plaque-associated microglia (PAMs) without interfering in the homeostatic functions of non-plaque associated microglia would afford a powerful tool and potential therapeutic avenue. METHODS Here, we demonstrated that a systemically administered nanomedicine, hydroxyl dendrimers (HDs), can cross the blood brain barrier and are preferentially taken up by PAMs in a mouse model of AD. As proof of principle, to demonstrate biological effects in PAM function, we treated the 5xFAD mouse model of amyloidosis for 4 weeks via systemic administration (ip, 2x weekly) of HDs conjugated to a colony stimulating factor-1 receptor (CSF1R) inhibitor (D-45113). RESULTS Treatment resulted in significant reductions in amyloid-beta (Aβ) and a stark reduction in the number of microglia and microglia-plaque association in the subiculum and somatosensory cortex, as well as a downregulation in microglial, inflammatory, and synaptic gene expression compared to vehicle treated 5xFAD mice. CONCLUSIONS This study demonstrates that systemic administration of a dendranib may be utilized to target and modulate PAMs.
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Affiliation(s)
- Caden M Henningfield
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697, USA
| | - Neelakshi Soni
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697, USA
| | - Ryan W Lee
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697, USA
| | - Rishi Sharma
- Ashvattha Therapeutics, Inc, Redwood City, CA, 94065, USA
| | | | - Kim N Green
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697, USA.
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4
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Vandermeulen L, Geric I, Fumagalli L, Kreir M, Lu A, Nonneman A, Premereur J, Wolfs L, Policarpo R, Fattorelli N, De Bondt A, Van Den Wyngaert I, Asselbergh B, Fiers M, De Strooper B, d'Ydewalle C, Mancuso R. Regulation of human microglial gene expression and function via RNAase-H active antisense oligonucleotides in vivo in Alzheimer's disease. Mol Neurodegener 2024; 19:37. [PMID: 38654375 PMCID: PMC11040766 DOI: 10.1186/s13024-024-00725-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 03/17/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND Microglia play important roles in maintaining brain homeostasis and neurodegeneration. The discovery of genetic variants in genes predominately or exclusively expressed in myeloid cells, such as Apolipoprotein E (APOE) and triggering receptor expressed on myeloid cells 2 (TREM2), as the strongest risk factors for Alzheimer's disease (AD) highlights the importance of microglial biology in the brain. The sequence, structure and function of several microglial proteins are poorly conserved across species, which has hampered the development of strategies aiming to modulate the expression of specific microglial genes. One way to target APOE and TREM2 is to modulate their expression using antisense oligonucleotides (ASOs). METHODS In this study, we identified, produced, and tested novel, selective and potent ASOs for human APOE and TREM2. We used a combination of in vitro iPSC-microglia models, as well as microglial xenotransplanted mice to provide proof of activity in human microglial in vivo. RESULTS We proved their efficacy in human iPSC microglia in vitro, as well as their pharmacological activity in vivo in a xenografted microglia model. We demonstrate ASOs targeting human microglia can modify their transcriptional profile and their response to amyloid-β plaques in vivo in a model of AD. CONCLUSIONS This study is the first proof-of-concept that human microglial can be modulated using ASOs in a dose-dependent manner to manipulate microglia phenotypes and response to neurodegeneration in vivo.
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Affiliation(s)
- Lina Vandermeulen
- Neuroscience Discovery, Janssen Research & Development, Janssen Pharmaceutica NV, 2340, Beerse, Belgium
| | - Ivana Geric
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, 3000, Belgium
- Laboratory for the Research of Neurodegenerative Diseases, Department of Neurosciences, Leuven Brain Institute (LBI), KU Leuven, Leuven, 3000, Belgium
| | - Laura Fumagalli
- MIND Lab, VIB Center for Molecular Neurology, VIB, 2610, Antwerp, Belgium
- Department of Biomedical Sciences, University of Antwerp, 2610, Antwerp, Belgium
| | - Mohamed Kreir
- Preclinical Development & Safety, Janssen Research & Development, Janssen Pharmaceutica NV, 2340, Beerse, Belgium
| | - Ashley Lu
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, 3000, Belgium
- Laboratory for the Research of Neurodegenerative Diseases, Department of Neurosciences, Leuven Brain Institute (LBI), KU Leuven, Leuven, 3000, Belgium
| | - Annelies Nonneman
- Neuroscience Discovery, Janssen Research & Development, Janssen Pharmaceutica NV, 2340, Beerse, Belgium
| | - Jessie Premereur
- MIND Lab, VIB Center for Molecular Neurology, VIB, 2610, Antwerp, Belgium
- Department of Biomedical Sciences, University of Antwerp, 2610, Antwerp, Belgium
| | - Leen Wolfs
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, 3000, Belgium
- Laboratory for the Research of Neurodegenerative Diseases, Department of Neurosciences, Leuven Brain Institute (LBI), KU Leuven, Leuven, 3000, Belgium
| | - Rafaela Policarpo
- Neuroscience Discovery, Janssen Research & Development, Janssen Pharmaceutica NV, 2340, Beerse, Belgium
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, 3000, Belgium
- Laboratory for the Research of Neurodegenerative Diseases, Department of Neurosciences, Leuven Brain Institute (LBI), KU Leuven, Leuven, 3000, Belgium
| | - Nicola Fattorelli
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, 3000, Belgium
- Laboratory for the Research of Neurodegenerative Diseases, Department of Neurosciences, Leuven Brain Institute (LBI), KU Leuven, Leuven, 3000, Belgium
| | - An De Bondt
- Discovery Sciences, Janssen Research & Development, Janssen Pharmaceutica NV, 2340, Beerse, Belgium
| | - Ilse Van Den Wyngaert
- Discovery Sciences, Janssen Research & Development, Janssen Pharmaceutica NV, 2340, Beerse, Belgium
| | - Bob Asselbergh
- Neuromics Support Facility, VIB Center for Molecular Neurology, University of Antwerp, 2610, Antwerp, Belgium
- Neuromics Support Facility, Department of Biomedical Sciences, University of Antwerp, 2610, Antwerp, Belgium
| | - Mark Fiers
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, 3000, Belgium
- Laboratory for the Research of Neurodegenerative Diseases, Department of Neurosciences, Leuven Brain Institute (LBI), KU Leuven, Leuven, 3000, Belgium
- UK Dementia Research Institute, University College London, London, W1T 7NF, UK
| | - Bart De Strooper
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, 3000, Belgium
- Laboratory for the Research of Neurodegenerative Diseases, Department of Neurosciences, Leuven Brain Institute (LBI), KU Leuven, Leuven, 3000, Belgium
- UK Dementia Research Institute, University College London, London, W1T 7NF, UK
| | - Constantin d'Ydewalle
- Neuroscience Discovery, Janssen Research & Development, Janssen Pharmaceutica NV, 2340, Beerse, Belgium.
| | - Renzo Mancuso
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, 3000, Belgium.
- Laboratory for the Research of Neurodegenerative Diseases, Department of Neurosciences, Leuven Brain Institute (LBI), KU Leuven, Leuven, 3000, Belgium.
- MIND Lab, VIB Center for Molecular Neurology, VIB, 2610, Antwerp, Belgium.
- Department of Biomedical Sciences, University of Antwerp, 2610, Antwerp, Belgium.
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5
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Zhang X, Chen C, Liu Y. Navigating the metabolic maze: anomalies in fatty acid and cholesterol processes in Alzheimer's astrocytes. Alzheimers Res Ther 2024; 16:63. [PMID: 38521950 PMCID: PMC10960454 DOI: 10.1186/s13195-024-01430-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 03/13/2024] [Indexed: 03/25/2024]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia, and its underlying mechanisms have been a subject of great interest. The mainstream theory of AD pathology suggests that the disease is primarily associated with tau protein and amyloid-beta (Aβ). However, an increasing body of research has revealed that abnormalities in lipid metabolism may be an important event throughout the pathophysiology of AD. Astrocytes, as important members of the lipid metabolism network in the brain, play a significant role in this event. The study of abnormal lipid metabolism in astrocytes provides a new perspective for understanding the pathogenesis of AD. This review focuses on the abnormal metabolism of fatty acids (FAs) and cholesterol in astrocytes in AD, and discusses it from three perspectives: lipid uptake, intracellular breakdown or synthesis metabolism, and efflux transport. We found that, despite the accumulation of their own fatty acids, astrocytes cannot efficiently uptake fatty acids from neurons, leading to fatty acid accumulation within neurons and resulting in lipotoxicity. In terms of cholesterol metabolism, astrocytes exhibit a decrease in endogenous synthesis due to the accumulation of exogenous cholesterol. Through a thorough investigation of these metabolic abnormalities, we can provide new insights for future therapeutic strategies by literature review to navigate this complex metabolic maze and bring hope to patients with Alzheimer's disease.
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Affiliation(s)
- Xiaoyu Zhang
- Department of Neurosurgery, Institute of Brain Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Chuanying Chen
- Department of Neurosurgery, Institute of Brain Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, 510515, China
- School of Traditional Chinese Medicine, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, Guangdong, 510515, People's Republic of China
| | - Yi Liu
- Department of Neurosurgery, Institute of Brain Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, 510515, China.
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6
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Sudwarts A, Thinakaran G. Alzheimer's genes in microglia: a risk worth investigating. Mol Neurodegener 2023; 18:90. [PMID: 37986179 PMCID: PMC10662636 DOI: 10.1186/s13024-023-00679-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Accepted: 11/07/2023] [Indexed: 11/22/2023] Open
Abstract
Despite expressing many key risk genes, the role of microglia in late-onset Alzheimer's disease pathophysiology is somewhat ambiguous, with various phenotypes reported to be either harmful or protective. Herein, we review some key findings from clinical and animal model investigations, discussing the role of microglial genetics in mediating perturbations from homeostasis. We note that impairment to protective phenotypes may include prolonged or insufficient microglial activation, resulting in dysregulated metabolomic (notably lipid-related) processes, compounded by age-related inflexibility in dynamic responses. Insufficiencies of mouse genetics and aggressive transgenic modelling imply severe limitations in applying current methodologies for aetiological investigations. Despite the shortcomings, widely used amyloidosis and tauopathy models of the disease have proven invaluable in dissecting microglial functional responses to AD pathophysiology. Some recent advances have brought modelling tools closer to human genetics, increasing the validity of both aetiological and translational endeavours.
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Affiliation(s)
- Ari Sudwarts
- Byrd Alzheimer's Center and Research Institute, University of South Florida, Tampa, FL, 33613, USA.
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA.
| | - Gopal Thinakaran
- Byrd Alzheimer's Center and Research Institute, University of South Florida, Tampa, FL, 33613, USA.
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA.
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7
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Abstract
All mammalian cell membranes contain cholesterol to maintain membrane integrity. The transport of this hydrophobic lipid is mediated by lipoproteins. Cholesterol is especially enriched in the brain, particularly in synaptic and myelin membranes. Aging involves changes in sterol metabolism in peripheral organs and also in the brain. Some of those alterations have the potential to promote or to counteract the development of neurodegenerative diseases during aging. Here, we summarize the current knowledge of general principles of sterol metabolism in humans and mice, the most widely used model organism in biomedical research. We discuss changes in sterol metabolism that occur in the aged brain and highlight recent developments in cell type-specific cholesterol metabolism in the fast-growing research field of aging and age-related diseases, focusing on Alzheimer's disease. We propose that cell type-specific cholesterol handling and the interplay between cell types critically influence age-related disease processes.
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Affiliation(s)
- Gesine Saher
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany;
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8
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Amontree M, Deasy S, Turner RS, Conant K. Matrix disequilibrium in Alzheimer's disease and conditions that increase Alzheimer's disease risk. Front Neurosci 2023; 17:1188065. [PMID: 37304012 PMCID: PMC10250680 DOI: 10.3389/fnins.2023.1188065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 04/20/2023] [Indexed: 06/13/2023] Open
Abstract
Alzheimer's Disease (AD) and related dementias are a leading cause of death globally and are predicted to increase in prevalence. Despite this expected increase in the prevalence of AD, we have yet to elucidate the causality of the neurodegeneration observed in AD and we lack effective therapeutics to combat the progressive neuronal loss. Throughout the past 30 years, several non-mutually exclusive hypotheses have arisen to explain the causative pathologies in AD: amyloid cascade, hyper-phosphorylated tau accumulation, cholinergic loss, chronic neuroinflammation, oxidative stress, and mitochondrial and cerebrovascular dysfunction. Published studies in this field have also focused on changes in neuronal extracellular matrix (ECM), which is critical to synaptic formation, function, and stability. Two of the greatest non-modifiable risk factors for development of AD (aside from autosomal dominant familial AD gene mutations) are aging and APOE status, and two of the greatest modifiable risk factors for AD and related dementias are untreated major depressive disorder (MDD) and obesity. Indeed, the risk of developing AD doubles for every 5 years after ≥ 65, and the APOE4 allele increases AD risk with the greatest risk in homozygous APOE4 carriers. In this review, we will describe mechanisms by which excess ECM accumulation may contribute to AD pathology and discuss pathological ECM alterations that occur in AD as well as conditions that increase the AD risk. We will discuss the relationship of AD risk factors to chronic central nervous system and peripheral inflammation and detail ECM changes that may follow. In addition, we will discuss recent data our lab has obtained on ECM components and effectors in APOE4/4 and APOE3/3 expressing murine brain lysates, as well as human cerebrospinal fluid (CSF) samples from APOE3 and APOE4 expressing AD individuals. We will describe the principal molecules that function in ECM turnover as well as abnormalities in these molecular systems that have been observed in AD. Finally, we will communicate therapeutic interventions that have the potential to modulate ECM deposition and turnover in vivo.
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Affiliation(s)
- Matthew Amontree
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC, United States
| | - Samantha Deasy
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC, United States
| | - R. Scott Turner
- Department of Neurology, Georgetown University Medical Center, Washington, DC, United States
| | - Katherine Conant
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC, United States
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9
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Hua J, Garcia de Paco E, Linck N, Maurice T, Desrumaux C, Manoury B, Rassendren F, Ulmann L. Microglial P2X4 receptors promote ApoE degradation and contribute to memory deficits in Alzheimer's disease. Cell Mol Life Sci 2023; 80:138. [PMID: 37145189 PMCID: PMC10163120 DOI: 10.1007/s00018-023-04784-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 04/18/2023] [Accepted: 04/19/2023] [Indexed: 05/06/2023]
Abstract
Numerous evidences support that microglia contributes to the progression of Alzheimer's disease. P2X4 receptors are ATP-gated channels with high calcium permeability, which are de novo expressed in a subset of reactive microglia associated with various pathological contexts, contributing to microglial functions. P2X4 receptors are mainly localized in lysosomes and trafficking to the plasma membrane is tightly regulated. Here, we investigated the role of P2X4 in the context of Alzheimer's disease (AD). Using proteomics, we identified Apolipoprotein E (ApoE) as a specific P2X4 interacting protein. We found that P2X4 regulates lysosomal cathepsin B (CatB) activity promoting ApoE degradation; P2rX4 deletion results in higher amounts of intracellular and secreted ApoE in both bone-marrow-derived macrophage (BMDM) and microglia from APPswe/PSEN1dE9 brain. In both human AD brain and APP/PS1 mice, P2X4 and ApoE are almost exclusively expressed in plaque-associated microglia. In 12-month-old APP/PS1 mice, genetic deletion of P2rX4 reverses topographical and spatial memory impairment and reduces amount of soluble small aggregates of Aß1-42 peptide, while no obvious alteration of plaque-associated microglia characteristics is observed. Our results support that microglial P2X4 promotes lysosomal ApoE degradation, indirectly altering Aß peptide clearance, which in turn might promotes synaptic dysfunctions and cognitive deficits. Our findings uncover a specific interplay between purinergic signaling, microglial ApoE, soluble Aß (sAß) species and cognitive deficits associated with AD.
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Affiliation(s)
- Jennifer Hua
- IGF, Univ Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science and Therapeutics, Montpellier, France
| | - Elvira Garcia de Paco
- IGF, Univ Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science and Therapeutics, Montpellier, France
| | - Nathalie Linck
- IGF, Univ Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science and Therapeutics, Montpellier, France
| | - Tangui Maurice
- MMDN, Univ Montpellier, EPHE, INSERM, Montpellier, France
| | | | - Bénédicte Manoury
- Institut Necker Enfants Malades, INSERM, CNRS, Université de Paris, Paris, France
| | - François Rassendren
- IGF, Univ Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science and Therapeutics, Montpellier, France
| | - Lauriane Ulmann
- IGF, Univ Montpellier, CNRS, INSERM, Montpellier, France.
- LabEx Ion Channel Science and Therapeutics, Montpellier, France.
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10
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Fujikawa R, Tsuda M. The Functions and Phenotypes of Microglia in Alzheimer's Disease. Cells 2023; 12:cells12081207. [PMID: 37190116 DOI: 10.3390/cells12081207] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/17/2023] [Accepted: 04/20/2023] [Indexed: 05/17/2023] Open
Abstract
Alzheimer's disease (AD) is the most prevalent neurodegenerative disease worldwide, but therapeutic strategies to slow down AD pathology and symptoms have not yet been successful. While attention has been focused on neurodegeneration in AD pathogenesis, recent decades have provided evidence of the importance of microglia, and resident immune cells in the central nervous system. In addition, new technologies, including single-cell RNA sequencing, have revealed heterogeneous cell states of microglia in AD. In this review, we systematically summarize the microglial response to amyloid-β and tau tangles, and the risk factor genes expressed in microglia. Furthermore, we discuss the characteristics of protective microglia that appear during AD pathology and the relationship between AD and microglia-induced inflammation during chronic pain. Understanding the diverse roles of microglia will help identify new therapeutic strategies for AD.
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Affiliation(s)
- Risako Fujikawa
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Makoto Tsuda
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
- Kyushu University Institute for Advanced Study, Fukuoka 819-0395, Japan
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11
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Lou T, Tao B, Chen M. Relationship of Apolipoprotein E with Alzheimer's Disease and Other Neurological Disorders: An Updated Review. Neuroscience 2023; 514:123-140. [PMID: 36736614 DOI: 10.1016/j.neuroscience.2023.01.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 01/21/2023] [Accepted: 01/25/2023] [Indexed: 02/05/2023]
Abstract
Alzheimer's disease (AD) and other neurodegenerative diseases, for which there is no effective cure, cause great social burden. Apolipoprotein E (APOE) is an important lipid transporter, which has been shown to have a close relationship with AD and other neurological disorders in an increasing number of studies, suggesting its potential as a therapeutic target. In this review, we summarize the recent advances in clinical and basic research on the role of APOE in the pathogenesis of multiple neurological diseases, with an emphasis on the new associations between APOE and AD, and between APOE and depression. The progress of APOE research in Parkinson's disease (PD) and some other neurological diseases is briefly discussed.
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Affiliation(s)
- Tianwen Lou
- The First Clinical Medical College, Anhui Medical University, Hefei, China; Department of Pharmacology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Borui Tao
- The First Clinical Medical College, Anhui Medical University, Hefei, China; Department of Pharmacology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Ming Chen
- Department of Pharmacology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China.
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12
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Logiacco F, Grzegorzek LC, Cordell EC, Popp O, Mertins P, Gutmann DH, Kettenmann H, Semtner M. Neurofibromatosis type 1-dependent alterations in mouse microglia function are not cell-intrinsic. Acta Neuropathol Commun 2023; 11:36. [PMID: 36890585 PMCID: PMC9996880 DOI: 10.1186/s40478-023-01525-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 02/05/2023] [Indexed: 03/10/2023] Open
Abstract
We previously discovered a sex-by-genotype defect in microglia function using a heterozygous germline knockout mouse model of Neurofibromatosis type 1 (Nf1 ± mice), in which only microglia from male Nf1 ± mice exhibited defects in purinergic signaling. Herein, we leveraged an unbiased proteomic approach to demonstrate that male, but not female, heterozygous Nf1 ± microglia exhibit differences in protein expression, which largely reflect pathways involved in cytoskeletal organization. In keeping with these predicted defects in cytoskeletal function, only male Nf1 ± microglia had reduced process arborization and surveillance capacity. To determine whether these microglial defects were cell autonomous or reflected adaptive responses to Nf1 heterozygosity in other cells in the brain, we generated conditional microglia Nf1-mutant knockout mice by intercrossing Nf1flox/flox with Cx3cr1-CreER mice (Nf1flox/wt; Cx3cr1-CreER mice, Nf1MG ± mice). Surprisingly, neither male nor female Nf1MG ± mouse microglia had impaired process arborization or surveillance capacity. In contrast, when Nf1 heterozygosity was generated in neurons, astrocytes and oligodendrocytes by intercrossing Nf1flox/flox with hGFAP-Cre mice (Nf1flox/wt; hGFAP-Cre mice, Nf1GFAP ± mice), the microglia defects found in Nf1 ± mice were recapitulated. Collectively, these data reveal that Nf1 ± sexually dimorphic microglia abnormalities are likely not cell-intrinsic properties, but rather reflect a response to Nf1 heterozygosity in other brain cells.
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Affiliation(s)
- Francesca Logiacco
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, 13125, Berlin, Germany
- Institute of Cell Biology and Neurobiology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, 10117, Berlin, Germany
| | - Laura Cathleen Grzegorzek
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, 13125, Berlin, Germany
- Institute of Cell Biology and Neurobiology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, 10117, Berlin, Germany
| | - Elizabeth C Cordell
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Oliver Popp
- Proteomics Platform, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, 13125, Berlin, Germany
| | - Philipp Mertins
- Proteomics Platform, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, 13125, Berlin, Germany
| | - David H Gutmann
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Helmut Kettenmann
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, 13125, Berlin, Germany
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Marcus Semtner
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, 13125, Berlin, Germany.
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13
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Koutsodendris N, Blumenfeld J, Agrawal A, Traglia M, Grone B, Zilberter M, Yip O, Rao A, Nelson MR, Hao Y, Thomas R, Yoon SY, Arriola P, Huang Y. Neuronal APOE4 removal protects against tau-mediated gliosis, neurodegeneration and myelin deficits. NATURE AGING 2023; 3:275-296. [PMID: 37118426 PMCID: PMC10154214 DOI: 10.1038/s43587-023-00368-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Accepted: 01/17/2023] [Indexed: 04/30/2023]
Abstract
Apolipoprotein E4 (APOE4) is the strongest known genetic risk factor for late-onset Alzheimer's disease (AD). Conditions of stress or injury induce APOE expression within neurons, but the role of neuronal APOE4 in AD pathogenesis is still unclear. Here we report the characterization of neuronal APOE4 effects on AD-related pathologies in an APOE4-expressing tauopathy mouse model. The selective genetic removal of APOE4 from neurons led to a significant reduction in tau pathology, gliosis, neurodegeneration, neuronal hyperexcitability and myelin deficits. Single-nucleus RNA-sequencing revealed that the removal of neuronal APOE4 greatly diminished neurodegenerative disease-associated subpopulations of neurons, oligodendrocytes, astrocytes and microglia whose accumulation correlated to the severity of tau pathology, neurodegeneration and myelin deficits. Thus, neuronal APOE4 plays a central role in promoting the development of major AD pathologies and its removal can mitigate the progressive cellular and tissue alterations occurring in this model of APOE4-driven tauopathy.
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Affiliation(s)
- Nicole Koutsodendris
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA, USA
- Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Jessica Blumenfeld
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA, USA
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Ayushi Agrawal
- Gladstone Institute of Data Science and Biotechnology, Gladstone Institutes, San Francisco, CA, USA
| | - Michela Traglia
- Gladstone Institute of Data Science and Biotechnology, Gladstone Institutes, San Francisco, CA, USA
| | - Brian Grone
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA, USA
- Gladstone Center for Translational Advancement, Gladstone Institutes, San Francisco, CA, USA
| | - Misha Zilberter
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA, USA
| | - Oscar Yip
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA, USA
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Antara Rao
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA, USA
- Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Maxine R Nelson
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA, USA
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Yanxia Hao
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA, USA
- Gladstone Center for Translational Advancement, Gladstone Institutes, San Francisco, CA, USA
| | - Reuben Thomas
- Gladstone Institute of Data Science and Biotechnology, Gladstone Institutes, San Francisco, CA, USA
| | - Seo Yeon Yoon
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA, USA
| | - Patrick Arriola
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA, USA
| | - Yadong Huang
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA, USA.
- Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, San Francisco, CA, USA.
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA.
- Gladstone Center for Translational Advancement, Gladstone Institutes, San Francisco, CA, USA.
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA, USA.
- Departments of Neurology and Pathology, University of California, San Francisco, San Francisco, CA, USA.
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14
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Martinez AE, Weissberger G, Kuklenyik Z, He X, Meuret C, Parekh T, Rees JC, Parks BA, Gardner MS, King SM, Collier TS, Harrington MG, Sweeney MD, Wang X, Zlokovic BV, Joe E, Nation DA, Schneider LS, Chui HC, Barr JR, Han SD, Krauss RM, Yassine HN. The small HDL particle hypothesis of Alzheimer's disease. Alzheimers Dement 2023; 19:391-404. [PMID: 35416404 PMCID: PMC10563117 DOI: 10.1002/alz.12649] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 02/08/2022] [Accepted: 02/12/2022] [Indexed: 01/03/2023]
Abstract
We propose the hypothesis that small high-density lipoprotein (HDL) particles reduce the risk of Alzheimer's disease (AD) by virtue of their capacity to exchange lipids, affecting neuronal membrane composition and vascular and synaptic functions. Concentrations of small HDLs in cerebrospinal fluid (CSF) and plasma were measured in 180 individuals ≥60 years of age using ion mobility methodology. Small HDL concentrations in CSF were positively associated with performance in three domains of cognitive function independent of apolipoprotein E (APOE) ε4 status, age, sex, and years of education. Moreover, there was a significant correlation between levels of small HDLs in CSF and plasma. Further studies will be aimed at determining whether specific components of small HDL exchange across the blood, brain, and CSF barriers, and developing approaches to exploit small HDLs for therapeutic purposes.
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Affiliation(s)
- Ashley E. Martinez
- Department of Medicine, University of Southern California, Los Angeles, California, USA
| | - Gali Weissberger
- The Interdisciplinary Department of Social Sciences, Bar Ilan University, Israel
| | - Zsuzsanna Kuklenyik
- Clinical Chemistry Branch, Division of Laboratory Sciences, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Xulei He
- Department of Medicine, University of Southern California, Los Angeles, California, USA
| | - Cristiana Meuret
- Department of Medicine, University of Southern California, Los Angeles, California, USA
| | - Trusha Parekh
- Department of Medicine, University of Southern California, Los Angeles, California, USA
| | - Jon C. Rees
- Clinical Chemistry Branch, Division of Laboratory Sciences, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Bryan A. Parks
- Clinical Chemistry Branch, Division of Laboratory Sciences, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Michael S. Gardner
- Clinical Chemistry Branch, Division of Laboratory Sciences, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Sarah M. King
- Departments of Pediatrics and Medicine, University of California, San Francisco, California, USA
| | | | - Michael G. Harrington
- Department of Neurology, University of Southern California, Los Angeles, California, USA
| | - Melanie D. Sweeney
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, USA
| | - Xinhui Wang
- Department of Neurology, University of Southern California, Los Angeles, California, USA
| | - Berislav V. Zlokovic
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, USA
| | - Elizabeth Joe
- Department of Neurology, University of Southern California, Los Angeles, California, USA
| | - Daniel A. Nation
- Irvine, Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, California, USA
| | - Lon S. Schneider
- Department of Neurology, University of Southern California, Los Angeles, California, USA
- Department of Psychiatry and Behavioral Sciences, University of Southern California, Los Angeles, California, USA
| | - Helena C. Chui
- Department of Neurology, University of Southern California, Los Angeles, California, USA
| | - John R. Barr
- Clinical Chemistry Branch, Division of Laboratory Sciences, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - S. Duke Han
- Department of Family Medicine, University of Southern California, Los Angeles, California, USA
| | - Ronald M. Krauss
- Departments of Pediatrics and Medicine, University of California, San Francisco, California, USA
| | - Hussein N. Yassine
- Department of Medicine, University of Southern California, Los Angeles, California, USA
- Department of Neurology, University of Southern California, Los Angeles, California, USA
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15
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Liu Y, Tan Y, Zhang Z, Li H, Yi M, Zhang Z, Hui S, Peng W. Neuroimmune mechanisms underlying Alzheimer's disease: Insights into central and peripheral immune cell crosstalk. Ageing Res Rev 2023; 84:101831. [PMID: 36565960 DOI: 10.1016/j.arr.2022.101831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 12/15/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
Alzheimer's disease (AD) is a highly life-threatening neurodegenerative disease. Dysregulation of the immune system plays a critical role in promoting AD, which has attracted extensive attention recently. Central and peripheral immune responses are involved in the pathogenesis of AD. Immune changes precede Aβ-associated senile plaque formation and tau-related neurofibrillary tangles, which are the recognised pathological features of AD. Therefore, elucidating immune-related mechanisms underlying the development of AD can help to prevent and treat AD at the source by blocking its progression before the development of pathological changes. To understand the specific pathogenesis of AD, it is important to examine the role of central and peripheral immunity in AD. This review summarises immune-related mechanisms underlying the pathogenesis of AD, focusing on the effect of various central and peripheral immune cells, and describes the possible crosstalk between central and peripheral immunity during the development of AD. This review provides novel insights into the treatment of AD and offers a new direction for immune-related research on AD in the future.
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Affiliation(s)
- Yuqing Liu
- Department of Integrated Traditional Chinese & Western Medicine, The Second Xiangya Hospital, Central South University, Changsha 410011, China; National Clinical Research Center for Metabolic Diseases, Changsha 410011, China.
| | - Yejun Tan
- School of Mathematics, University of Minnesota Twin Cities, Minneapolis, MN, USA.
| | - Zheyu Zhang
- Department of Integrated Traditional Chinese & Western Medicine, The Second Xiangya Hospital, Central South University, Changsha 410011, China; National Clinical Research Center for Metabolic Diseases, Changsha 410011, China.
| | - Hongli Li
- Department of Integrated Traditional Chinese & Western Medicine, The Second Xiangya Hospital, Central South University, Changsha 410011, China; National Clinical Research Center for Metabolic Diseases, Changsha 410011, China.
| | - Min Yi
- Department of Integrated Traditional Chinese & Western Medicine, The Second Xiangya Hospital, Central South University, Changsha 410011, China; National Clinical Research Center for Metabolic Diseases, Changsha 410011, China.
| | - Zhen Zhang
- YangSheng College of Traditional Chinese Medicine, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, Guizhou, China.
| | - Shan Hui
- Department of Geratology, Hunan Provincial People's Hospital, The First Affiliated Hospital of Hunan Normal University, Changsha 410005, China.
| | - Weijun Peng
- Department of Integrated Traditional Chinese & Western Medicine, The Second Xiangya Hospital, Central South University, Changsha 410011, China; National Clinical Research Center for Metabolic Diseases, Changsha 410011, China.
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16
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Chen X, Holtzman DM. Emerging roles of innate and adaptive immunity in Alzheimer's disease. Immunity 2022; 55:2236-2254. [PMID: 36351425 PMCID: PMC9772134 DOI: 10.1016/j.immuni.2022.10.016] [Citation(s) in RCA: 67] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 08/15/2022] [Accepted: 10/18/2022] [Indexed: 11/09/2022]
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disease, with characteristic extracellular amyloid-β (Aβ) deposition and intracellular accumulation of hyperphosphorylated, aggregated tau. Several key regulators of innate immune pathways are genetic risk factors for AD. While these genetic risk factors as well as in vivo data point to key roles for microglia, emerging evidence also points to a role of the adaptive immune response in disease pathogenesis. We review the roles of innate and adaptive immunity, their niches, their communication, and their contributions to AD development and progression. We also summarize the cellular compositions and physiological functions of immune cells in the parenchyma, together with those in the brain border structures that form a dynamic disease-related immune niche. We propose that both innate and adaptive immune responses in brain parenchyma and border structures could serve as important therapeutic targets for treating both the pre-symptomatic and the symptomatic stages of AD.
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Affiliation(s)
- Xiaoying Chen
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - David M Holtzman
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA.
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17
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Heavener KS, Bradshaw EM. The aging immune system in Alzheimer's and Parkinson's diseases. Semin Immunopathol 2022; 44:649-657. [PMID: 35505128 PMCID: PMC9519729 DOI: 10.1007/s00281-022-00944-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 04/20/2022] [Indexed: 11/03/2022]
Abstract
The neurodegenerative diseases Alzheimer's disease (AD) and Parkinson's disease (PD) both have a myriad of risk factors including genetics, environmental exposures, and lifestyle. However, aging is the strongest risk factor for both diseases. Aging also profoundly influences the immune system, with immunosenescence perhaps the most prominent outcome. Through genetics, mouse models, and pathology, there is a growing appreciation of the role the immune system plays in neurodegenerative diseases. In this review, we explore the intersection of aging and the immune system in AD and PD.
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Affiliation(s)
- Kelsey S Heavener
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Elizabeth M Bradshaw
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, 10032, USA.
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18
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Huang J, Li C, Shang H. Astrocytes in Neurodegeneration: Inspiration From Genetics. Front Neurosci 2022; 16:882316. [PMID: 35812232 PMCID: PMC9268899 DOI: 10.3389/fnins.2022.882316] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 06/06/2022] [Indexed: 12/19/2022] Open
Abstract
Despite the discovery of numerous molecules and pathologies, the pathophysiology of various neurodegenerative diseases remains unknown. Genetics participates in the pathogenesis of neurodegeneration. Neural dysfunction, which is thought to be a cell-autonomous mechanism, is insufficient to explain the development of neurodegenerative disease, implying that other cells surrounding or related to neurons, such as glial cells, are involved in the pathogenesis. As the primary component of glial cells, astrocytes play a variety of roles in the maintenance of physiological functions in neurons and other glial cells. The pathophysiology of neurodegeneration is also influenced by reactive astrogliosis in response to central nervous system (CNS) injuries. Furthermore, those risk-gene variants identified in neurodegenerations are involved in astrocyte activation and senescence. In this review, we summarized the relationships between gene variants and astrocytes in four neurodegenerative diseases, including Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and Parkinson’s disease (PD), and provided insights into the implications of astrocytes in the neurodegenerations.
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19
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Xu YJ, Au NPB, Ma CHE. Functional and Phenotypic Diversity of Microglia: Implication for Microglia-Based Therapies for Alzheimer’s Disease. Front Aging Neurosci 2022; 14:896852. [PMID: 35693341 PMCID: PMC9178186 DOI: 10.3389/fnagi.2022.896852] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 05/05/2022] [Indexed: 12/21/2022] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disease and is closely associated with the accumulation of β-amyloid (Aβ) and neurofibrillary tangles (NFTs). Apart from Aβ and NFT pathologies, AD patients also exhibit a widespread microglial activation in various brain regions with elevated production of pro-inflammatory cytokines, a phenomenon known as neuroinflammation. In healthy central nervous system, microglia adopt ramified, “surveying” phenotype with compact cell bodies and elongated processes. In AD, the presence of pathogenic proteins such as extracellular Aβ plaques and hyperphosphorylated tau, induce the transformation of ramified microglia into amoeboid microglia. Ameboid microglia are highly phagocytic immune cells and actively secrete a cascade of pro-inflammatory cytokines and chemokines. However, the phagocytic ability of microglia gradually declines with age, and thus the clearance of pathogenic proteins becomes highly ineffective, leading to the accumulation of Aβ plaques and hyperphosphorylated tau in the aging brain. The accumulation of pathogenic proteins further augments the neuroinflammatory responses and sustains the activation of microglia. The excessive production of pro-inflammatory cytokines induces a massive loss of functional synapses and neurons, further worsening the disease condition of AD. More recently, the identification of a subset of microglia by transcriptomic studies, namely disease-associated microglia (DAM), the progressive transition from homeostatic microglia to DAM is TREM2-dependent and the homeostatic microglia gradually acquire the state of DAM during the disease progression of AD. Recent in-depth transcriptomic analysis identifies ApoE and Trem2 from microglia as the major risk factors for AD pathogenesis. In this review, we summarize current understandings of the functional roles of age-dependent microglial activation and neuroinflammation in the pathogenesis of AD. To this end, the exponential growth in transcriptomic data provides a solid foundation for in silico drug screening and gains further insight into the development of microglia-based therapeutic interventions for AD.
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Affiliation(s)
- Yi-Jun Xu
- Department of Neuroscience, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Ngan Pan Bennett Au
- Department of Neuroscience, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Chi Him Eddie Ma
- Department of Neuroscience, City University of Hong Kong, Kowloon, Hong Kong SAR, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
- *Correspondence: Chi Him Eddie Ma,
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20
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Mahan TE, Wang C, Bao X, Choudhury A, Ulrich JD, Holtzman DM. Selective reduction of astrocyte apoE3 and apoE4 strongly reduces Aβ accumulation and plaque-related pathology in a mouse model of amyloidosis. Mol Neurodegener 2022; 17:13. [PMID: 35109920 PMCID: PMC8811969 DOI: 10.1186/s13024-022-00516-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 01/13/2022] [Indexed: 12/11/2022] Open
Abstract
Background One of the key pathological hallmarks of Alzheimer disease (AD) is the accumulation of the amyloid-β (Aβ) peptide into amyloid plaques. The apolipoprotein E (APOE) gene is the strongest genetic risk factor for late-onset AD and has been shown to influence the accumulation of Aβ in the brain in an isoform-dependent manner. ApoE can be produced by different cell types in the brain, with astrocytes being the largest producer of apoE, although reactive microglia also express high levels of apoE. While studies have shown that altering apoE levels in the brain can influence the development of Aβ plaque pathology, it is not fully known how apoE produced by specific cell types, such as astrocytes, contributes to amyloid pathology. Methods We utilized APOE knock-in mice capable of having APOE selectively removed from astrocytes in a tamoxifen-inducible manner and crossed them with the APP/PS1-21 mouse model of amyloidosis. We analyzed the changes to Aβ plaque levels and assessed the impact on cellular responses to Aβ plaques when astrocytic APOE is removed. Results Tamoxifen administration was capable of strongly reducing apoE levels in the brain by markedly reducing astrocyte apoE, while microglial apoE expression remained. Reduction of astrocytic apoE3 and apoE4 led to a large decrease in Aβ plaque deposition and less compact plaques. While overall Iba1+ microglia were unchanged in the cortex after reducing astrocyte apoE, the expression of the disease-associated microglial markers Clec7a and apoE were lower around amyloid plaques, indicating decreased microglial activation. Additionally, astrocyte GFAP levels are unchanged around amyloid plaques, but overall GFAP levels are reduced in the cortex of female apoE4 mice after a reduction in astrocytic apoE. Finally, while the amount of neuritic dystrophy around remaining individual plaques was increased with the removal of astrocytic apoE, the overall amount of cortical amyloid-associated neuritic dystrophy was significantly decreased. Conclusion This study reveals an important role of astrocytic apoE3 and apoE4 on the deposition and accumulation of Aβ plaques as well as on certain Aβ-associated downstream effects. Supplementary Information The online version contains supplementary material available at 10.1186/s13024-022-00516-0.
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Affiliation(s)
- Thomas E Mahan
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
| | - Chao Wang
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
| | - Xin Bao
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
| | - Ankit Choudhury
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
| | - Jason D Ulrich
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO, 63110, USA
| | - David M Holtzman
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO, 63110, USA.
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21
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Paasila PJ, Aramideh JA, Sutherland GT, Graeber MB. Synapses, Microglia, and Lipids in Alzheimer's Disease. Front Neurosci 2022; 15:778822. [PMID: 35095394 PMCID: PMC8789683 DOI: 10.3389/fnins.2021.778822] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 12/06/2021] [Indexed: 12/17/2022] Open
Abstract
Alzheimer's disease (AD) is characterised by synaptic dysfunction accompanied by the microscopically visible accumulation of pathological protein deposits and cellular dystrophy involving both neurons and glia. Late-stage AD shows pronounced loss of synapses and neurons across several differentially affected brain regions. Recent studies of advanced AD using post-mortem brain samples have demonstrated the direct involvement of microglia in synaptic changes. Variants of the Apolipoprotein E and Triggering Receptors Expressed on Myeloid Cells gene represent important determinants of microglial activity but also of lipid metabolism in cells of the central nervous system. Here we review evidence that may help to explain how abnormal lipid metabolism, microglial activation, and synaptic pathophysiology are inter-related in AD.
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Affiliation(s)
- Patrick J. Paasila
- Charles Perkins Centre, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, Australia
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
| | - Jason A. Aramideh
- Brain and Mind Centre, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, Australia
| | - Greg T. Sutherland
- Charles Perkins Centre, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, Australia
| | - Manuel B. Graeber
- Brain and Mind Centre, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, Australia
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22
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Barahona RA, Morabito S, Swarup V, Green KN. Cortical diurnal rhythms remain intact with microglial depletion. Sci Rep 2022; 12:114. [PMID: 34997092 PMCID: PMC8742049 DOI: 10.1038/s41598-021-04079-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/01/2021] [Indexed: 12/15/2022] Open
Abstract
Microglia are subject to change in tandem with the endogenously generated biological oscillations known as our circadian rhythm. Studies have shown microglia harbor an intrinsic molecular clock which regulates diurnal changes in morphology and influences inflammatory responses. In the adult brain, microglia play an important role in the regulation of condensed extracellular matrix structures called perineuronal nets (PNNs), and it has been suggested that PNNs are also regulated in a circadian and diurnal manner. We sought to determine whether microglia mediate the diurnal regulation of PNNs via CSF1R inhibitor dependent microglial depletion in C57BL/6J mice, and how the absence of microglia might affect cortical diurnal gene expression rhythms. While we observe diurnal differences in microglial morphology, where microglia are most ramified at the onset of the dark phase, we do not find diurnal differences in PNN intensity. However, PNN intensity increases across many brain regions in the absence of microglia, supporting a role for microglia in the regulation of PNNs. Here, we also show that cortical diurnal gene expression rhythms are intact, with no cycling gene changes without microglia. These findings demonstrate a role for microglia in the maintenance of PNNs, but not in the maintenance of diurnal rhythms.
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Affiliation(s)
- Rocio A Barahona
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697, USA
| | - Samuel Morabito
- Mathematical, Computational and Systems Biology (MCSB) Program, University of California, Irvine, CA, USA
| | - Vivek Swarup
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697, USA
| | - Kim N Green
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697, USA.
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